<1> UI - 491XV-0001 DD - ISI Document Solution: 491XV AU - Niinemets U AU - Ellsworth DS AU - Lukjanova A AU - Tobias M RA - Niinemets U TI - Site fertility and the morphological and photosynthetic acclimation of Pinus sylvestris needles to light SO - Tree Physiology. 21(17):1231-1244, 2001 Nov. AS - Tree Physiol 2001 Nov;21(17):1231-1244 PU - HERON PUBLISHING, 202, 3994 SHELBOURNE ST, VICTORIA, BC V8N 3E2, CANADA. URL: http://www.heronpublishing.com IS - 0829-318X MH - Leaf density MH - Leaf thickness MH - Leaf structure MH - Light acclimation MH - Nitrogen availability MH - Phosphorus availability MH - Photosynthetic capacity. MH - Temperate deciduous trees MH - Leaf nitrogen concentration MH - Picea-abies seedlings MH - Electron-transport MH - Norway spruce MH - Phosphorus-nutrition MH - Scots pine MH - Chlorophyll fluorescence MH - Stomatal conductance MH - Eucalyptus-grandis. AB - Morphological and photosynthetic acclimation of current-year needles to canopy gradients in light availability (seasonal mean integrated quantum flux density, Q(int)) was studied in the temperate conifer, Pinus sylvestris L., at two sites of contrasting nutrient availability. The nutrient-rich site supported a monospecific P. sylvestris stand on an old-field. The trees were approximately 30 years old and 19-21 m tall. Mean foliar N and P contents (+/- SD) were 1.53 +/- 0.11 % and 0.196 +/- 0.017%, respectively. The nutrient-poor site was located on a raised bog supporting a sparse stand of 50- to 100-year-old trees, with a height of 1-2 m, and mean needle N and P contents of 0.86 +/- 0.12% and 0.074 +/- 0.010%, respectively. At both sites, needle thickness (T) and width (W) increased with increasing Q(int), and leaf dry mass per unit leaf area (M-A) was also greater at higher irradiance. The light effects on M-A-the product of needle density (D) and volume to total area ratio (V/A(T))-resulted primarily from large increases in V/A(T) with Q(int) rather than from modifications of D, which was relatively insensitive to light. Although needle morphology versus light relationships were qualitatively similar at both sites, needles were shorter, and the slopes of W, T, M-A and V/A(T) versus light relationships were lower, at the nutrient-poor than at the nutrient-rich site, indicating that the plasticity of foliar morphological characteristics was affected by nutrient availability. As a result of lower plasticity, needles at the nutrient-poor site were narrower, thinner, and had lower MA at high irradiance than needles at the nutrient-rich site. The maximum carboxylase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (V-cmax) and the maximum photosynthetic electron transport rate (J(max)) scaled positively with foliar N and P contents. The correlations were generally stronger with P than with N, suggesting that needle photosynthetic capacity was more heavily limited by the availability of P than of N. The J(max)/V-cmax ratio was positively related to the foliar P/N ratio, indicating that J(max) was more strongly suppressed than V-cmax under conditions of low P availability. Phosphorus and N deficiency also limited the plasticity of foliar photosynthetic characteristics. There was a moderate increase in needle photosynthetic capacity of up to 1.6-fold from the bottom to the top of the canopy at the nutrient-rich site, but net assimilation rates were essentially independent of canopy position at the nutrient-poor site. Stomatal constraints on photosynthesis were similar between the sites, indicating that photosynthetic acclimation was curtailed at the biochemical level. We conclude that the foliar capacity for morphological and physiological acclimation to high light significantly decreases with decreasing nutrient availability in P. sylvestris, and that both N and P availability are potentially important determinants of foliar carbon gain capacities. [References: 99] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Niinemets U Univ Tartu, Inst Mol & Cell Biol, Dept Plant Physiol Riia 23 EE-51011 Tartu Estonia Univ Tartu, Inst Mol & Cell Biol, Dept Plant Physiol EE-51011 Tartu Estonia Univ Michigan, Sch Nat Resources & Environm Ann Arbor, MI 48109 USA Tallinn Univ Educ Sci, Dept Ecophysiol, Inst Ecol EE-10137 Tallinn Estonia <2> UI - 491DR-0008 DD - ISI Document Solution: 491DR AU - Thomas DS AU - Turner DW MA - d.thomas@uws.edu.au RA - Thomas DS TI - Banana (Musa sp.) leaf gas exchange and chlorophyll fluorescence in response to soil drought, shading and lamina folding SO - Scientia Horticulturae. 90(1-2):93-108, 2001 Oct 29. AS - Sci. Hortic 2001 Oct 29;90(1-2):93-108 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0304-4238 MH - Banana MH - Musa MH - Photosynthesis MH - Photoinhibition MH - Chlorophyll fluorescence. MH - Photosynthetic reactions MH - Water-stress MH - Leaves MH - Photoinhibition MH - Temperature MH - Light MH - Inhibition MH - Depression MH - Plant MH - Spp.. AB - Reductions in net photosynthesis of banana (Musa sp.) leaves may be due to both stomatal and non-stomatal limitations. To evaluate the significance of photochemical damage, we measured chlorophyll fluorescence in conjunction with net photosynthesis. Photochemical damage was reflected in either an increase in original fluorescence (F-O), or decreases in maximum fluorescence (F-M) or in the ratio of variable (F-V = F-M - F-O) to maximal fluorescence (F-V/F-M). The leaf surface receiving direct sunlight (adaxial) was more photochemically damaged, as measured by declines in chlorophyll fluorescence parameters than the abaxial leaf surface that received transmitted and indirect light. Damage increased over a diurnal period and was greater in droughted compared with irrigated plants. F-V/F-M ratio declined significantly as plant water status, measured as relative leaf water content or leaf water potential, declined. The decrease in the F-V/F-M ratio was due more to a decline in F-M than an increase in F-O. Shading of plants decreased photochemical damage in leaves but net photosynthesis (P-n) was lower than in sunlit plants because of the limitation of P-n by low photosynthetic photon flux density. A combination of stomatal and non-stomatal factors reduced P-n in droughted or shaded plants. Excessive sunlight can cause photochemical damage to banana leaves but this damage does not appear to be a limitation of P-n in well-irrigated plants. The natural folding of banana laminae (not caused by wilting) reduces photochemical damage by reducing the flux density of radiation intercepted by the lamina surface. (C) 2001 Elsevier Science B.V All rights reserved. [References: 21] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Thomas DS Univ Western Sydney Hawkesbury, Ctr Hort & Plant Sci Locked Bag 1 Richmond NSW 2753 Australia Univ Western Australia, Fac Agr Nedlands WA 6907 Australia <3> UI - 493TX-0051 DD - ISI Document Solution: 493TX AU - Berman-Frank I AU - Lundgren P AU - Chen YB AU - Kupper H AU - Kolber Z AU - Bergman B AU - Falkowski P MA - irfrank@imcs.rutgers.edu RA - Berman-Frank I TI - Segregation of nitrogen fixation and oxygenic photosynthesis in the marine cyanobacterium Trichodesmium SO - Science. 294(5546):1534-1537, 2001 Nov 16. AS - Science 2001 Nov 16;294(5546):1534-1537 PU - AMER ASSOC ADVANCEMENT SCIENCE, 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA. URL: http://www.aaas.org IS - 0036-8075 MH - Nonheterocystous cyanobacterium MH - Chlorophyll fluorescence MH - Fixing microorganisms MH - N-2 fixation MH - Thiebautii MH - Expression MH - Rhythm MH - Oceans MH - Genes MH - Cells. AB - In the modern ocean, a significant amount of nitrogen fixation is attributed to filamentous, nonheterocystous cyanobacteria of the genus Trichodesmium. In these organisms, nitrogen fixation is confined to the photoperiod and occurs simultaneously with oxygenic photosynthesis. Nitrogenase, the enzyme responsible for biological N-2 fixation, is irreversibly inhibited by oxygen in vitro. How nitrogenase is protected from damage by photosynthetically produced O-2 was once an enigma. Using fast repetition rate fluorometry and fluorescence kinetic microscopy, we show that there is both temporal and spatial segregation of N-2 fixation and photosynthesis within the photoperiod. Linear photosynthetic electron transport protects nitrogenase by reducing photosynthetically evolved O-2 in photosystem I (PSI). We postulate that in the early evolutionary phase of oxygenic photosynthesis, nitrogenase served as an electron acceptor for anaerobic heterotrophic metabolism and that PSI was favored by selection because it provided a micro-anaerobic environment for N-2 fixation in cyanobacteria. [References: 35] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences Current Contents(R)/Physical, Chemical & Earth Sciences CC - Multidisciplinary in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Multidisciplinary in Current Contents(R)/Life Sciences. Multidisciplinary in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Berman-Frank I Rutgers State Univ, Inst Marine & Coastal Sci, Environm Biophys & Mol Ecol Program 71 Dudley Rd New Brunswick, NJ 08901 USA Rutgers State Univ, Inst Marine & Coastal Sci, Environm Biophys & Mol Ecol Program New Brunswick, NJ 08901 USA Stockholm Univ, Dept Bot SE-10691 Stockholm Sweden Inst Microbiol, Photosynth Res Ctr CZ-37981 Trebon Czech Republic Univ S Bohemia, Lab Biomembranes CZ-37005 Ceske Budejovice Czech Republic Univ Konstanz, Fac Sci, Dept Biol D-78457 Constance Germany <4> UI - 493KF-0032 DD - ISI Document Solution: 493KF AU - Mamleeva NA AU - Kropacheva TN AU - Mitrofanova AN AU - Ben'ko EM AU - Pryakhin AN RA - Mamleeva NA TI - Energy transfer in adsorption layers of chlorophyll a on the surface of a protein SO - Russian Journal of Physical Chemistry. 75(11):1917-1923, 2001 Nov. AS - Russ. J. Phys. Chem 2001 Nov;75(11):1917-1923 PU - INTERPERIODICA, PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA. URL: http://www.maik.rssi.ru/eng/dist.htm IS - 0036-0244 MH - Spectral characteristics MH - Photosystem-ii MH - Fluorescence MH - Absorption. AB - Absorption and fluorescence spectra of chlorophyll a (Chl a) adsorbed on the surface of bovine serum albumin (BSA) were measured and decomposed into Gaussian components. The contributions from the individual components to the absorption and fluorescence spectra as functions of the Chl a surface concentration were determined. It was shown that a decrease in the average distances between the molecules of the pigment in the system results in the transfer of singlet excitation energy from Chl a monomers to various associates of the pigment. Energy transfer in adsorption layers of the pigment on BSA involves Chl a forms characteristic of the chloroplast membranes of higher plants. [References: 20] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Physical Chemistry/Chemical Physics in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Mamleeva NA Moscow MV Lomonosov State Univ, Fac Chem Vorobevy Gory Moscow 119899 Russia Moscow MV Lomonosov State Univ, Fac Chem Moscow 119899 Russia Udmurt State Univ Izhevsk 426034 Russia <5> UI - 490WM-0109 DD - ISI Document Solution: 490WM AU - Zak E AU - Norling B AU - Maitra R AU - Huang F AU - Andersson B AU - Pakrasi HB MA - Pakrasi@biology.wustl.edu RA - Pakrasi HB TI - The initial steps of biogenesis of cyanobacterial photosystems occur in plasma membranes SO - Proceedings of the National Academy of Sciences of the United States of America. 98(23):13443-13448, 2001 Nov 6. AS - Proc. Natl. Acad. Sci. U. S. A 2001 Nov 6;98(23):13443-13448 PU - NATL ACAD SCIENCES, 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA. URL: http://www4.nationalacademies.org/nas/nashome.nsf IS - 0027-8424 MH - Terminal processing protease MH - Ii reaction-center MH - Scenedesmus-obliquus MH - Anacystis-nidulans MH - Pcc 6803 MH - Complex MH - D1 MH - Gene MH - Organization MH - Proteins. AB - During oxygenic photosynthesis in cyanobacteria and chloroplasts of plants and eukaryotic algae, conversion of light energy to biologically useful chemical energy occurs in the specialized thylakoid membranes. Light-induced charge separation at the reaction centers of photosystems I and II, two multisubunit pigment-protein complexes in the thylakoid membranes, energetically drive sequential photosynthetic electron transfer reactions in this membrane system. In general, in the prokaryotic cyanobacterial cells, the thylakoid membrane is distinctly different from the plasma membrane. We have recently developed a two-dimensional separation procedure to purify thylakoid and plasma membranes from the genetically widely studied cyanobacterium Synechocystis sp. PCC 6803. Immunoblotting analysis demonstrated that the purified plasma membrane contained a number of protein components closely associated with the reaction centers of both photosystems. Moreover,these proteins were assembled in the plasma membrane as chlorophyll-containing multiprotein complexes, as evidenced from nondenaturing green gel and low-temperature fluorescence spectroscopy data. Furthermore, electron paramagnetic resonance spectroscopic analysis showed that in the partially assembled photosystem I core complex in the plasma membrane, the P700 reaction center was capable of undergoing light-induced charge separation. Based on these data, we propose that the plasma membrane, and not the thylakoid membrane, is the site for a number of the early steps of biogenesis of the photosynthetic reaction center complexes in these cyanobacterial cells. [References: 40] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Multidisciplinary in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Pakrasi HB Washington Univ, Dept Biol Campus Box 1137,1 Brookings Dr St Louis, MO 63130 USA Washington Univ, Dept Biol St Louis, MO 63130 USA Stockholm Univ, Arrhenius Labs Nat Sci, Dept Biochem SE-10691 Stockholm Sweden Linkoping Univ, Div Cell Biol SE-58185 Linkoping Sweden <6> UI - 492AY-0015 DD - ISI Document Solution: 492AY AU - Ruffle SV AU - Wang J AU - Johnston HG AU - Gustafson TL AU - Hutchison RS AU - Minagawa J AU - Crofts A AU - Sayre RT MA - sayre.2@osu.edu RA - Sayre RT TI - Photosystem II peripheral accessory chlorophyll mutants in Chlamydomonas reinhardtii. Biochemical characterization and sensitivity to photo-inhibition SO - Plant Physiology. 127(2):633-644, 2001 Oct. AS - Plant Physiol 2001 Oct;127(2):633-644 PU - AMER SOC PLANT BIOLOGISTS, 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA. URL: http://www.aspp.org IS - 0032-0889 MH - Reaction center complex MH - Donor side MH - 3-dimensional model MH - Thylakoid membrane MH - D1 protein MH - Photoinhibition MH - Excitation MH - Cytochrome-b-559 MH - Chloroplast MH - Mutagenesis. AB - In addition to the four chlorophylls (Chls) involved in primary charge separation, the photosystem II (PSII) reaction center polypeptides, D1 and D2, coordinate a pair of symmetry-related, peripheral accessory Chls. These Chls are axially coordinated by the D1-H118 and D2-H117 residues and are in close association with the proximal Chl antennae proteins, CP43 and CP47. To gain insight into the function(s) of each of the peripheral Chls, we generated site-specific mutations of the amino acid residues that coordinate these Chls and characterized their energy and electron transfer properties. Our results demonstrate that D1-H118 and D2-H117 mutants differ with respect to: (a) their relative numbers of functional PSII complexes, (b) their relative ability to stabilize charge-separated states, (c) light-harvesting efficiency, and (d) their sensitivity to photo-inhibition. The D2-H117N and D2-H117Q mutants had reduced levels of functional PSII complexes and oxygen evolution capacity as well as reduced light-harvesting efficiencies relative to wild-type cells. In contrast, the D1-H118Q mutant was capable of near wild-type rates of oxygen evolution at saturating light intensities. The D1-H118Q mutant also was substantially more resistant to photo-inhibition than wild type. This reduced sensitivity to photo-inhibition is presumably associated with a reduced light-harvesting efficiency in this mutant. Finally, it is noted that the PSII peripheral accessory Chls have similarities to a to a pair of Chls also present in the PSI reaction center complex. [References: 47] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Sayre RT Ohio State Univ, Dept Plant Biol 1735 Neil Ave Columbus, OH 43210 USA Ohio State Univ, Dept Plant Biol Columbus, OH 43210 USA Ohio State Univ, Dept Chem Columbus, OH 43210 USA Univ Exeter, Sch Biol Sci Exeter EX4 4PS Devon England N Dakota State Univ, Dept Biol Fargo, ND 58105 USA Hokkaido Univ, Inst Low Temp Sci Sapporo Hokkaido 0600819 Japan Univ Illinois, Dept Biophys Urbana, IL 61801 USA Univ Illinois, Dept Computat Biol & Microbiol Urbana, IL 61801 USA <7> UI - 492AY-0020 DD - ISI Document Solution: 492AY AU - Veljovic-Jovanovic SD AU - Pignocchi C AU - Noctor G AU - Foyer CH MA - christine.foyer@bbsrc.ac.uk RA - Foyer CH TI - Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system SO - Plant Physiology. 127(2):426-435, 2001 Oct. AS - Plant Physiol 2001 Oct;127(2):426-435 PU - AMER SOC PLANT BIOLOGISTS, 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA. URL: http://www.aspp.org IS - 0032-0889 MH - Photosynthetic electron-transport MH - Hydrogen-peroxide MH - 2-cysteine peroxiredoxin MH - Vitamin-c MH - Glutathione MH - Leaves MH - Biosynthesis MH - Chloroplasts MH - Expression MH - Isozymes. AB - Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This lesion was associated with a slight increase in total glutathione but no change in the redox state of either ascorbate or glutathione. In vtc-1, total ascorbate in the apoplast was decreased to 23% of the wild-type value. The mutant displayed much slower shoot growth than the wild type when grown in air or at high CO2 (3 mL L-1), where oxidative stress is diminished. Leaves were smaller, and shoot fresh weight and dry weight were lower in the mutant. No significant differences in the light saturation curves for CO, assimilation were found in air or at high CO2, suggesting that the effect on growth was not due to decreased photosynthetic capacity in the mutant. Analysis of chlorophyll a fluorescence quenching revealed only a slight effect on non-photochemical energy dissipation. Hydrogen peroxide contents were similar in the leaves of the vtc-1 mutant and the wild type. Total leaf peroxidase activity was increased in the mutant and compartment-specific differences in ascorbate peroxidase (APX) activity were observed. In agreement with the measurements of enzyme activity, the expression of cytosolic APX was increased, whereas that for chloroplast APX isoforms was either unchanged or slightly decreased. These data implicate ascorbate concentration in the regulation of the compartmentalization of the antioxidant system in Arabidopsis. [References: 39] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Foyer CH Inst Arable Crops Res Rothamsted, Dept Biochem & Physiol Harpenden AL5 2JQ Herts England Inst Arable Crops Res Rothamsted, Dept Biochem & Physiol Harpenden AL5 2JQ Herts England Univ Belgrade, Ctr Multidisciplinary Studies YU-11030 Belgrade Yugoslavia <8> UI - 492AY-0031 DD - ISI Document Solution: 492AY AU - Feild TS AU - Lee DW AU - Holbrook NM MA - tfeild@oeb.harvard.edu RA - Feild TS TI - Why leaves turn red in autumn. The role of anthocyanins in senescing leaves of red-osier dogwood SO - Plant Physiology. 127(2):566-574, 2001 Oct. AS - Plant Physiol 2001 Oct;127(2):566-574 PU - AMER SOC PLANT BIOLOGISTS, 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA. URL: http://www.aspp.org IS - 0032-0889 MH - Low-temperature stress MH - Chlorophyll fluorescence MH - Leaf senescence MH - Light-stress MH - Electron-transport MH - Optical-properties MH - Photoinhibition MH - Plants MH - Photosynthesis MH - Photoprotection. AB - Why the leaves of many woody species accumulate anthocyanins prior to being shed has long puzzled biologists because it is unclear what effects anthocyanins may have on leaf function. Here, we provide evidence for red-osier dogwood (Cornus stolonifera) that anthocyanins form a pigment layer in the palisade mesophyll layer that decreases light capture by chloroplasts. Measurements of leaf absorbance demonstrated that red-senescing leaves absorbed more light of blue-green to orange wavelengths (495-644 nm) compared with yellow-senescing leaves. Using chlorophyll a fluorescence measurements, we observed that maximum photosystem II (PSII) photon yield of red-senescing leaves recovered from a high-light stress treatment, whereas yellow-senescing leaves failed to recover after 6 h of dark adaptation, which suggests photo-oxidative damage. Because no differences were observed in light response curves of effective PSII photon yield for red- and yellow-senescing leaves, differences between red- and yellow-senescing cannot be explained by differences in the capacities for photochemical and non-photochemical light energy dissipation. A role of anthocyanins as screening pigments was explored further by measuring the responses PSII photon yield to blue light, which is preferentially absorbed by anthocyanins, versus red light, which is poorly absorbed. We found that dark-adapted PSII photon yield of red-senescing leaves recovered rapidly following illumination with blue light. However, red light induced a similar, prolonged decrease in PSII photon yield in both red- and yellow-senescing leaves. We suggest that optical masking of chlorophyll by anthocyanins reduces risk of photo-oxidative damage to leaf cells as they senesce, which otherwise may lower the efficiency of nutrient retrieval from senescing autumn leaves. [References: 65] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Feild TS Univ Calif Berkeley, Dept Integrat Biol 3060 Valley Life Sci Bldg 3140 Berkeley, CA 94720 USA Fairchild Trop Garden Miami, FL 33199 USA Florida Int Univ, Dept Biol Sci Miami, FL 33199 USA Harvard Univ, Dept Organism & Evolutionary Biol Cambridge, MA 02138 USA <9> UI - 493AF-0003 DD - ISI Document Solution: 493AF AU - Dring MJ AU - Wagner A AU - Luning K MA - m.dring@qub.ac.uk RA - Dring MJ TI - Contribution of the UV component of natural sunlight to photoinhibition of photosynthesis in six species of subtidal brown and red seaweeds SO - Plant, Cell & Environment. 24(11):1153-1164, 2001 Nov. AS - Plant Cell Environ 2001 Nov;24(11):1153-1164 PU - BLACKWELL SCIENCE LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0140-7791 MH - Pam fluorometry MH - Phaeophyceae MH - Rhodophyceae MH - Uv radiation. MH - Ultraviolet-b radiation MH - Liquidambar styraciflua hamamelidaceae MH - Fluorescence measurements MH - Chlorophyll fluorescence MH - Arctic macroalgae MH - Solar irradiation MH - Growth MH - Field MH - Sensitivity MH - Inhibition. AB - Field-collected specimens of three species of Laminaria and three species of subtidal red algae (Delesseria sanguinea, Plocamium cartilagineum and Phyllophora pseudoceranoides) were exposed to natural summer sunlight on Helgoland (southern North Sea) for up to 4 h at 15 degreesC. Dark-adapted variable fluorescence (F-v : F-m) was measured immediately after these treatments, and following 6, 24 and 48 h of recovery in moderate irradiances of white light. The response of plants to the full spectrum of natural sunlight was compared with that to PAR alone, UV-A + visible, UV-A + UV-B, or UV-A alone. The F-v:F-m values of all species were reduced to minimal values after 4 h in all of these treatments, but those of the more resistant species (Laminaria spp. and P. pseudoceranoides) were higher after shorter exposures to UV radiation alone than to PAR with or without UV. The recovery of F-v:F-m in all species was also more rapid in the two treatments that contained UV radiation alone than in those that included PAR. These results suggest that it is the high irradiances of PAR in natural sunlight which are responsible for the photoinhibition of photosynthesis of subtidal seaweeds and that the current ambient irradiances of UV radiation (either UV-B or UV-A) in northern temperate latitudes would not contribute significantly to this photoinhibition. [References: 39] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Dring MJ Queens Univ, Marine Lab Portaferry BT22 1PF Down North Ireland Meeresstn Helgoland, Biol Anstalt Helgoland Helgoland Germany <10> UI - 493HT-0004 DD - ISI Document Solution: 493HT AU - Kornyeyev D AU - Logan BA AU - Payton P AU - Allen RD AU - Holaday AS MA - bdash@ttacs.ttu.edu RA - Holaday AS TI - Enhanced photochemical light utilization and decreased chilling-induced photoinhibition of photosystem II in cotton overexpressing genes encoding chloroplast-targeted antioxidant enzymes SO - Physiologia Plantarum. 113(3):323-331, 2001 Nov. AS - Physiol. Plant 2001 Nov;113(3):323-331 PU - MUNKSGAARD INT PUBL LTD, 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK. URL: http://www.munksgaard.dk IS - 0031-9317 MH - Photosynthetic electron-transport MH - Chlorophyll fluorescence MH - Superoxide-dismutase MH - Low-temperature MH - Glutathione-reductase MH - Transgenic plants MH - Oxidative stress MH - Ascorbate peroxidase MH - Active oxygen MH - Leaves. AB - The aim of this study was to determine whether increases in stromal superoxide dismutase (SOD; EC 1.15.1.1), ascorbate peroxidase (APX; EC 1.11.1.11) and glutathione reductase (GR; EC 1.6.4.2) via transformation could reduce photosystem (PS) II photoinhibition at low temperature for cotton (Gossypium hirsutum L.) plants and to determine by what mechanism this protection may be realized. During 3-h exposures of lincomycin-treated leaf discs to 10 degreesC and a photon flux density of 500 pmol m(-2) s(-1), all transgenic plants exhibited significantly greater PSII activity and O-2 evolution than did wild-type plants. Also, the rate constant of PSII photoinactivation was significantly lower for all transgenic plants than for wild-type plants. No significant differences existed between genotypes in non-photochemical quenching of chlorophyll a fluorescence and the regulated component of the thermal dissipation of excitation energy. The relationship between changes in variable to maximum chlorophyll fluorescence (F-v/F-m) and the time-dependent averaged excessive light exposure was similar for all genotypes. This observation excluded the possibility that differences in PSII photodamage were due to improvements in the direct protection of PSII from active oxygen by antioxidant enzyme overproduction. Similar decreases in F-v/F-m during the stress treatment for all genotypes when leaves were pre-treated with 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU) suggested that the effect of overproduction involved events downstream of PSH in the electron transfer pathway. Since all transgenic plants exhibited a significantly higher photochemical quenching of chlorophyll fluorescence during the chilling treatment, we concluded that, under the conditions used in this study, the enhancement of the protection of PSII from photodamage by increasing the stromal antioxidant enzyme activity in cotton leaves was due to the maintenance of a higher rate of electron transport and, consequently, a lower reduction state of QA. [References: 60] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Holaday AS Texas Tech Univ, Dept Biol Sci Lubbock, TX 79409 USA Texas Tech Univ, Dept Biol Sci Lubbock, TX 79409 USA Bowdoin Coll, Dept Biol Brunswick, ME 04011 USA <11> UI - 493HT-0006 DD - ISI Document Solution: 493HT AU - Michaeli R AU - Philosoph-Hadas S AU - Riov J AU - Shahak Y AU - Ratner K AU - Meir S MA - soniap@netvision.net.il RA - Meir S TI - Chilling-induced leaf abscission of Ixora coccinea plants. III. Enhancement by high light via increased oxidative processes SO - Physiologia Plantarum. 113(3):338-345, 2001 Nov. AS - Physiol. Plant 2001 Nov;113(3):338-345 PU - MUNKSGAARD INT PUBL LTD, 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK. URL: http://www.munksgaard.dk IS - 0031-9317 MH - Glutathione-s-transferase MH - Low-temperature MH - Lipid-peroxidation MH - Hydrogen-peroxide MH - Maize seedlings MH - Active oxygen MH - Stress MH - Photoinhibition MH - Reductase MH - Sensitivity. AB - The role of increased oxidation induced by successive stresses of chilling and high light in the induction of leaf abscission was studied in Ixora coccinea plants in relation to auxin metabolism and oxidative processes. Exposure of plants following dark chilling (7 degreesC for 3 days) to high light (500-700 mu mol m(-2) s(-1) photosynthetically active radiation) for 5 h at 20-25 degreesC enhanced chilling-induced leaf abscission. This abscission was inhibited by pretreatment with the antioxidant butylated hydroxyanisole, ae-naphthaleneacetic acid or the ethylene action inhibitor, 1-methylcyclopropene. The oxidative processes initiated during the low light period following the dark chilling period, such as indoleacetic acid (IAA) decarboxylation and lipid peroxidation, were further enhanced by subsequent exposure to high light. Photoinhibition, expressed by the reduction of the chlorophyll fluorescence parameter Fv/Fm, was evident following exposure to high light, irrespective of the temperature of the pretreatment, but this reduction persisted only in chilled plants. This suggests that oxidative processes generated during and after the chilling period might have inhibited the recovery from photoinhibition. The chilling stress under darkness induced a 60%, reduction in superoxide dismutase (SOD) activity and significant increases (130-600%) in the activities of several other antioxidative enzymes. These data suggest that the chilling-induced reduction in SOD activity may well be responsible for the increase in the oxidative stress induced by the subsequent light treatment, as expressed by the increased enzymatic activities. Taken together, this study provides further support for the involvement of oxidative processes in the events occurring in tissues exposed to sequential chilling and light stresses, leading to reduction in free IAA content in the abscission zone and to leaf abscission. [References: 43] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Meir S Agr Res Org, Volcani Ctr, Dept Postharvest Sci Fresh Produce POB 6 IL-50250 Bet Dagan Israel Agr Res Org, Volcani Ctr, Dept Postharvest Sci Fresh Produce IL-50250 Bet Dagan Israel Hebrew Univ Jerusalem, Fac Agr, Kennedy Leigh Ctr Hort Res IL-76100 Rehovot Israel Agr Res Org, Volcani Ctr, Inst Hort IL-50250 Bet Dagan Israel <12> UI - 493HT-0018 DD - ISI Document Solution: 493HT AU - Padmavathi L AU - Raghavendra AS MA - asrsl@uohyd.ernet.in RA - Raghavendra AS TI - Importance of the cytochrome pathway of mitochondrial electron transport over the alternative pathway during the Kok effect in leaf discs of pea (Pisum sativum) SO - Physiologia Plantarum. 113(3):430-434, 2001 Nov. AS - Physiol. Plant 2001 Nov;113(3):430-434 PU - MUNKSGAARD INT PUBL LTD, 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK. URL: http://www.munksgaard.dk IS - 0031-9317 MH - Dark respiration MH - Oxidative-phosphorylation MH - Mesophyll protoplasts MH - Quantum yield MH - Light MH - Photosynthesis MH - Plants MH - Chloroplasts MH - Interdependence MH - Temperature. AB - The Kok effect refers to the progressive light-induced inhibition of dark respiration at low light intensities, which saturates around the light compensation point. This appears as a sudden break around the light compensation point in the plot of photosynthesis versus light intensity. The magnitude of the break can be considered as a measure of the Kok effect. In the present work, the importance of different components of dark respiration during the Kok effect was investigated by using low concentrations of mitochondrial inhibitors in leaf discs of pea (Pisum sativum L. cv. Azad PI). The effects of glucose (stimulates respiration) and 0.8 M sorbitol (imposes osmotic stress and inhibits photosynthesis) were also studied for comparison. The magnitude of the break decreased significantly in the presence of antimycin A or oligomycin (inhibitors of cytochrome pathway of mitochondrial electron transport and ATP synthase, respectively). In contrast, there was no significant change with salicylhydroxamic acid (SHAM; an inhibitor of alternative pathway of mitochondrial electron transport). The magnitude of the break increased significantly with glucose, and decreased on exposure to osmotic stress. Our results suggest that the Kok effect (inhibition of dark respiration in light) is modulated by inhibitors of cytochrome pathway and ATP synthesis, but not that of the alternative pathway. [References: 35] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Raghavendra AS Univ Hyderabad, Sch Life Sci, Dept Plant Sci Hyderabad 500046 Andhra Pradesh India Univ Hyderabad, Sch Life Sci, Dept Plant Sci Hyderabad 500046 Andhra Pradesh India <13> UI - 491MJ-0001 DD - ISI Document Solution: 491MJ AU - Lidon FC AU - Loureiro AS AU - Vieira DE AU - Bilho EA AU - Nobre P AU - Costa R MA - fjl@mail.fct.unl.pt RA - Lidon FC TI - Photoinhibition in chilling stressed wheat and maize SO - Photosynthetica. 39(2):161-166, 2001. AS - Photosynthetica 2001;39(2):161-166 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Carotenoids MH - Chlorophyll MH - Cytochrome b(559) MH - Lipid peroxidation MH - Photosystems 1 and 2 MH - Proteins MH - Quinones MH - Triticum MH - Xanthophyll cycle MH - Zea. MH - Ii reaction center MH - Photosystem-ii MH - Electron-transport MH - Beta-carotene MH - Excess copper MH - Rice plants MH - Photosynthesis MH - Chloroplasts MH - Light MH - Leaves. AB - At chilling stress. the contents of photosynthetic pigments decreased significantly in maize, but in wheat the contents of chlorophyll (Chi) remained unchanged whereas the contents of total carotenoids (Car) increased. In both species the contents of alpha+beta carotene and lutein + lutein-5,6-epoxide remained unaffected, but the de-epoxidation state involving the components of the xanthophyll cycle increased. Under chilling stress the photosynthetic electron transport also displayed a general failure in maize but in wheat only photosystem (PS) 2 coupled to the water oxidation complex was inhibited. Moreover, in stressed maize the quinone pool decreased, while the low and high potential forms of cytochrome b(559) increased. In wheat only the contents of cytochrome b(559LP) decreased. Peroxidation of acyl lipids in the chloroplast lamellae became more distinct in chilling stressed maize but could also be detected in wheat. Thus in chilling stressed maize prevails an impairment of the acceptor site of PS2 while in wheat photodamage is restricted to the electron donation pathway from water to P680 or to the oxygen evolving complex. [References: 35] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Lidon FC Grp Disciplinas Ecol Hidrosfera Quinta Torre P-2825114 Caparica Portugal Grp Disciplinas Ecol Hidrosfera P-2825114 Caparica Portugal <14> UI - 491MJ-0002 DD - ISI Document Solution: 491MJ AU - Jiao DM AU - Li X MA - photosyn@public1.ptt.js.cn RA - Jiao DM TI - Cultivar differences in photosynthetic tolerance to photooxidation and shading in rice (Oryza sativa L.) SO - Photosynthetica. 39(2):167-175, 2001. AS - Photosynthetica 2001;39(2):167-175 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll MH - Grain MH - Irradiance MH - Net photosynthetic rate MH - Photooxidation MH - Photosynthetic characteristics MH - Photosystems 1 and 2 MH - Ribulose-1,5-bisphosphate carboxylase MH - Shoot dry mass MH - Superoxide dismutase. MH - Ribulose-1,5-bisphosphate carboxylase MH - Growth irradiance MH - Low-temperature MH - Protein damage MH - Photoinhibition MH - Plants MH - Photoprotection MH - Acclimation MH - Chloroplast MH - Increase. AB - Forty-four genotypes from the rice germplasm were identified under photoinhibition/photooxidation and shade conditions and divided into four basic types: (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to both photooxidation and shading. Photosynthetic characteristics of a cultivar tolerant (cv. Wuyugeng 3) and a cultivar sensitive (cv. Xiangxian) to photooxidation and shading were compared. The photochemical efficiency (F-v/F-m) of photosystem 2 (PS2) and the content of PS2-D1 protein in the tolerant cultivar Wuyugeng 3 decreased less under photooxidative conditions as compared with Xiangxian. Under similar conditions, superoxide dismutase was induced rapidly to a higher activity and the active oxygen (O-) built up to a lower level in Wuyugeng 3 than in Xiangxian. Net photosynthetic rate (P-N) decreased by 23 % in Wuyugeng 3 vs. 64 % in Xiangxian. Shading (80 %) during the booting stage caused only small decreases (7-13 %) in ribulose-1,5-bisphosphate carboxylase activity and P-N in Wuyugeng 3 but severe, decreases (57-64 %) were observed in Xiangxian which corresponded to the decreases in grain yield of the two cultivars. (38 and 73 %, respectively). We describe a simple and effective screening method and physiological basis for breeding crops for enhanced tolerance to both high and low irradiance. [References: 41] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Jiao DM Jiangsu Acad Agr Sci, Inst Agrobiol Genet & Physiol Nanjing 210014 Peoples R China Jiangsu Acad Agr Sci, Inst Agrobiol Genet & Physiol Nanjing 210014 Peoples R China <15> UI - 491MJ-0004 DD - ISI Document Solution: 491MJ AU - Zhu XY AU - Chen GC AU - Zhang CL MA - zhangcl@lzu.edu.cn RA - Zhang CL TI - Photosynthetic electron transport, photophosphorylation, and antioxidants in two ecotypes of reed (Phragmites communis Trin.) from different habitats SO - Photosynthetica. 39(2):183-189, 2001. AS - Photosynthetica 2001;39(2):183-189 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Antioxidant MH - Ascorbate peroxidase MH - Chloroplast MH - Cyclic electron flow MH - Mg2+-atpase MH - Natural drought MH - Photosystem 1 and 2 activities MH - Stomatal resistance MH - Superoxide dismutase MH - Transpiration rate. MH - Water-stress MH - Spinach-chloroplasts MH - Photosystem-ii MH - Metabolism MH - Leaves MH - Expression MH - Cycle MH - Illumination MH - Protoplasts MH - Carboxylase. AB - We compared chloroplast photochemical properties and activities of some chloroplast-localised enzymes in two ecotypes of Phragmites communis, swamp reed (SR, C-3-like) and dune reed (DR, C-4-like) plants growing in the desert region of north-west China. Electron transport rates of whole electron transport chain and photosystem (PS) 2 were remarkably lower in DR chloroplasts. However, the electron transport rate for PS1 in DR chloroplasts was more than 90 % of the activity similar in the SR chloroplasts. Activities of Mg2+-ATPase and cyclic and non-cyclic photophosphorylations were higher in DR chloroplasts than in the SR ones. The activities of chloroplast superoxide dismutase (SOD) and ascorbate peroxidase (APX), both localised at or near the PS1 complex and serving to scavenge active oxygen around PS1, and the content of ascorbic acid, a special substrate of APX in chloroplast, were all higher in DR chloroplasts. Hence reed, a hydrophytic plant, when subjected to intense selection pressure in dune habitat, elevates its cyclic electron flow around PS1. In consequence, it provides extra ATP required by C-4 photosynthesis. Combined high activities of active oxygen scavenging components in DR chloroplasts might improve protection of photosynthetic apparatus, especially PS1, from the damage of reactive oxygen species. This offers new explanation of photosynthetic performance of plant adaptation to long-term natural drought habitat, which is different from those, subjected to the short-term stress treatment or even to the artificial field drought. [References: 49] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Zhang CL Lanzhou Univ, Dept Biol Lanzhou 730000 Gansu Peoples R China Lanzhou Univ, Dept Biol Lanzhou 730000 Gansu Peoples R China <16> UI - 491MJ-0010 DD - ISI Document Solution: 491MJ AU - Li Y AU - Zhang JP AU - Zhao JQ AU - Jiang LJ MA - zhaojq@ipc.ac.cn RA - Zhao JQ TI - Regulation mechanism of excitation energy transfer in phycobilisome-thylakoid membrane complexes SO - Photosynthetica. 39(2):227-232, 2001. AS - Photosynthetica 2001;39(2):227-232 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Absorption spectra MH - Allophycocyanin MH - Betaine MH - Dcmu MH - Fluorescence spectra MH - Models of energy transfer MH - N-ethylmaleimide MH - Photosystems 1 and 2 MH - State transition. MH - Cyanobacterium-synechococcus 6301 MH - State-ii MH - Porphyridium-cruentum MH - Photosystem-ii MH - Transition MH - Phosphorylation MH - Photosynthesis MH - Polypeptides MH - Spectra MH - Alga. AB - Regulation mechanism of excitation energy transfer between phycobilisomes (PBS) and the photosynthetic reaction centres was studied by the state transition techniques in PBS-thylakoid membrane complexes. DCMU, betaine, and N-ethylmaleimide were applied to search for the details of energy transfer properties based on the steady fluorescence measurement and individual deconvolution spectra at state 2 or state 1. The closure of photosystem (PS) 2 did not influence on fluorescence yields of PS1, i.e., energy could not spill to PS1 from PS2. When the energy transfer pathway from PBS to PS1 was disturbed, the relative fluorescence yield of PS2 was almost the same as that of PS2 in complexes without treatment. If PBSs were fixed by betaine, the state transition process was restrained. Hence PBS may detach from PS2 and become associated to PS1 at state 2. Our results contradict the proposed "spill-over" or "PBS detachment" models and support the mobile "PBS model". [References: 22] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Zhao JQ Chinese Acad Sci, Inst Photog Chem Beijing 100101 Peoples R China Chinese Acad Sci, Inst Chem, Ctr Mol Sci Beijing 100080 Peoples R China <17> UI - 491MJ-0012 DD - ISI Document Solution: 491MJ AU - Wang ZM AU - Wei AL AU - Zheng DM MA - zhimin206@263.net RA - Wang ZM TI - Photosynthetic characteristics of non-leaf organs of winter wheat cultivars differing in ear type and their relationship with grain mass per ear SO - Photosynthetica. 39(2):239-244, 2001. AS - Photosynthetica 2001;39(2):239-244 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll MH - Net photosynthetic rate MH - Photosystem 2 MH - Ribulose-1,5-bisphosphate carboxylase/oxygenase MH - Triticum aestivum. MH - Flag leaf. AB - Chlorophyll content, photosystem 2 functioning (F-v/F-m, F-v/F-0), activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, and net photosynthetic rates (P-N) of flag leaf blade, sheath, peduncle, and ear organs were assessed in large-ear type (Pin 7) and small-ear type (ND93) wheat cultivars. Some differences were found in photosynthetic properties between different green plant parts, the values of all studied parameters in ear parts being higher in Pin7 than in ND93. Furthermore, ear surface areas and ear P-N in 26 wheat genotypes measured at anthesis showed highly significant positive correlation with grain mass per ear. Hence a greater capability of car photosynthesis may result in a greater grain yield in large-ear type cultivars. [References: 13] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Wang ZM China Agr Univ, Dept Agron Beijing 100094 Peoples R China China Agr Univ, Dept Agron Beijing 100094 Peoples R China <18> UI - 491MJ-0013 DD - ISI Document Solution: 491MJ AU - Serret MD AU - Trillas MI AU - Matas J AU - Araus JL MA - josel@porthos.bio.ub.es RA - Araus JL TI - The effect of photoautotrophy on photosynthesis and photoinhibition of gardenia plantlets during micropropagation SO - Photosynthetica. 39(2):245-255, 2001. AS - Photosynthetica 2001;39(2):245-255 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll fluorescence MH - Gardenia jasminoides MH - In vitro culture MH - Irradiance MH - Photosynthetic pigments MH - Respiration MH - Root induction MH - Saccharose MH - Shoot multiplication MH - Vapour pressure deficit. MH - Grown in-vitro MH - Juglans-regia plantlets MH - Chlorophyll fluorescence MH - Ex-vitro MH - Co2 concentration MH - High-temperature MH - Rose shootlets MH - O-2 evolution MH - Photon yield MH - Light. AB - We studied the relationships between the degree of photoautotrophy, photosynthetic capacity, and extent of photoinhibition of Gardenia jasminoides Ellis plantlets. in vitro. Two successive micropropagation stages (shoot multiplication and root induction), and three culture conditions [tube cap closure, photosynthetic photon flux density (PPFD), and sucrose concentration] which may influence the development of photoautotrophy in vitro were assayed. The ratios of variable chlorophyll fluorescence to either maximal (F-v/F-m) or ground (F-v/F-0) values were low, irrespective of the culture stage or growing conditions. Incomplete development of the photosynthetic apparatus and permanent photoinhibition may be involved. However, F-v/F-m and F-v/F-0 increased from shoot multiplication to root induction owing to a decrease in F-0 and an increase in F-m. This suggests that photoinhibition decreases later during micropropagation, when the photoautotrophy of plantlets is more advanced. The low sucrose content and high PPFD increased the photoinhibition of plantlets, whereas growth in tubes with permeable caps showed the opposite effect. The only culture factor with a significant (positive) effect on maximum photosynthetic rate (P-max) was PPFD. At shoot multiplication net photosynthetic rate (P-N) was positively correlated with the half time of the increase from F-0 to F-m (t(1/2)). Such association may be mainly due to a common response of both traits to higher PPFD in culture. Within each culture stage, no relationship was observed between P-N and the degree of photoautotrophy, which was positively correlated with F-v/F-m and F-v/F-0 during root induction. During shoot multiplication, these correlations were not significant, or were even negative. Hence during the last stage of micropropagation, plantlets with a higher degree of photoautotrophy are less photoinhibited, whereas they do not follow this pattern at the earlier stage. [References: 64] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Araus JL Univ Barcelona, Fac Biol, Unitat Fisiol Vegetal Avgda Diagonal 645 E-08028 Barcelona Spain Univ Barcelona, Fac Biol, Unitat Fisiol Vegetal E-08028 Barcelona Spain <19> UI - 491MJ-0014 DD - ISI Document Solution: 491MJ AU - Jiang GM AU - Zhu GJ MA - jgm@ht.rol.cn.net RA - Jiang GM TI - Different patterns of gas exchange and photochemical efficiency in three desert shrub species under two natural temperatures and irradiances in Mu Us Sandy Area of China SO - Photosynthetica. 39(2):257-262, 2001. AS - Photosynthetica 2001;39(2):257-262 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Artemisia ordosia MH - Chlorophyll fluorescence MH - Diurnal courses MH - Hedysarum fruticosum var. mongolicum MH - High irradiance MH - High temperature MH - Photosynthetic rate MH - Photosystem 2 MH - Stomatal conductance MH - Salix pasmmophylla. MH - Chlorophyll fluorescence MH - Seasonal-changes MH - Drought stress MH - Quercus-ilex MH - Water-stress MH - Photosynthesis MH - Co2 MH - Capacity MH - Fixation. AB - Field studies of gas exchange and chlorophyll fluorescence of three desert shrub species, Hedysarum fruticosum var. mongolicum, Artemisia ordosia, and Salix pasmmophylla, showed different patterns under different leaf temperature (T-1) and incident photosynthetic photon flux density (PPFD). H. fruticosum var. mongolicum and A. ordosia exhibited higher P-N and g(s) than S. pasmmophylla, especially under very high T-1 (> 46 degreesC) and high PPFD (>2 100 mu mol m(-2) s(-1)) in hot summer. The decreases of P-N with the diurnal course were due mainly to stomata closure. However, P-N of S. pasmmophylla was seriously depressed by very high temperature from midday to evening as shown by the negative PN in hot summer, whereas none of such depression was found in spring. Maximal spring photochemical efficiency of photosystem 2 (PS2), i.e., F-v/F-m, was the lowest at 16:00, indicating the injury of PS2 by heat at this stage. In hot summer again, all the three shrubs underwent pronounced midday depression of P-N and g(s), while in spring they showed a one-peak response. And the first peak appeared 2 h earlier in hot summer than in spring for all the three shrubs. It was the high temperature that led to the different patterns of gas exchange and the serious depression of P-N in S. pasmmophylla. H. fruticosum var. mongolicum and A. ordosia were much more tolerant to heat and high irradiance than S. pasmmophylla, which fixed most of CO2 at the fast growing stage in spring. Nevertheless, in hot summer it had to survive the severe hot environment through strong respiration and storage of CO2 only in the early morning. [References: 25] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Jiang GM Chinese Acad Sci, Inst Bot, Lab Quantitat Vegetat Ecol 20 Nanxincun Beijing 100093 Peoples R China Chinese Acad Sci, Inst Bot, Lab Quantitat Vegetat Ecol Beijing 100093 Peoples R China <20> UI - 491MJ-0015 DD - ISI Document Solution: 491MJ AU - Kalapos T AU - Mazsa K MA - kalapos@ludens.elte.hu, mazsa@botanika.hu RA - Kalapos T TI - Juniper shade enables terricolous lichens and mosses to maintain high photochemical efficiency in a semiarid temperate sand grassland SO - Photosynthetica. 39(2):263-268, 2001. AS - Photosynthetica 2001;39(2):263-268 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Bryophytes MH - Chlorophyll a fluorescence MH - Cladonia MH - Diplosichtes MH - Hypnum MH - Neofuscelia MH - Polytrichum MH - Tortula. MH - Chlorophyll fluorescence MH - Hydric environments MH - Lobaria-pulmonaria MH - High-light MH - Desiccation MH - Forest MH - Cyanobacterial MH - Photosynthesis MH - Responses MH - Growth. AB - On a semiarid sand grassland (Festucetum vaginatae) colonised by juniper (Juniperus communis L.) shrubs terricolous lichens and mosses segregate strongly between microhabitats: certain species grow in the open grassland, others almost exclusively in the shade of junipers. The contrasting irradiances of these microhabitats influence much the metabolism of these organisms, and thus affect their small-scale distribution. This was confirmed by determining the efficiency of photochemical energy conversion by measuring chlorophyll a fluorescence parameters. In the open grassland maximum photochemical efficiency of photosystem 2 (PS2, F-v/F-m) declined from the humid spring to the hot and dry summer in all species, and this was caused by an increase in base fluorescence (F-0), but not by the decrease in fluorescence maximum (F-m). In summer, mosses and lichens growing in the open grassland generally possessed lower F-v/F-m than cryptogams growing in the shade cast by juniper shrubs. Thus mosses and lichens in the open grassland suffer lasting reduction in photochemical efficiency in summer, which is avoided in the shade of junipers. Juniper shrubs indeed influence the composition and small-scale spatial pattern of sympatric terricolous lichen and moss communities by-among others-providing a shelter against high light in summer. [References: 34] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Kalapos T Lorand Eotvos Univ, Dept Plant Taxonomy & Ecol Ludovika Ter 2 H-1083 Budapest Hungary Lorand Eotvos Univ, Dept Plant Taxonomy & Ecol H-1083 Budapest Hungary <21> UI - 491MJ-0016 DD - ISI Document Solution: 491MJ AU - Jiang CD AU - Gao HY AU - Zou Q MA - zouqi@sdau.edu.cn RA - Zou Q TI - Enhanced thermal energy dissipation depending on xanthophyll cycle and D1 protein turnover in iron-deficient maize leaves under high irradiance SO - Photosynthetica. 39(2):269-274, 2001. AS - Photosynthetica 2001;39(2):269-274 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Carboxylation efficiency MH - Carotenoids MH - Chlorophyll MH - Co2 concentration MH - Fluorescence kinetics MH - Energy dissipation MH - Net photosynthetic rate MH - Photosystems MH - Zea mays. MH - Photosystem-ii MH - Chlorophyll fluorescence MH - In-vivo MH - Photoinhibition MH - Chloroplasts MH - Plants MH - Photoprotection MH - Photosynthesis MH - Stress MH - Temperature. AB - Pigment contents of chloroplasts and net photosynthetic rate were dramatically reduced in maize leaves suffering from iron deficiency. However, the reduction in photosynthesis was probably not caused by decreased contents of chlorophylls and carotenoids. and by photon absorption; the primary limiting factor for photosynthesis may rather be the decrease of electron transport activity in photosystem 1. Iron-deficient leaves suffered serious acceptor-side photoinhibition, and more than 60 % of absorbed photons were dissipated, while less than 40 % was used in photochemical reaction. Thermal energy dissipation depending on xanthophyll cycle and D1 protein turnover was enhanced when acceptor-side photoinhibition occurred in iron-deficient maize leaves. [References: 22] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Zou Q Shandong Agr Univ, Dept Plant Sci Shandong 271018 Peoples R China Shandong Agr Univ, Dept Plant Sci Shandong 271018 Peoples R China <22> UI - 491MJ-0017 DD - ISI Document Solution: 491MJ AU - Urban L AU - Barthelemy L AU - Bearez P AU - Pyrrha P RA - Urban L TI - Effect of elevated CO2 on photosynthesis and chlorophyll fluorescence of rose plants grown at high temperature and high photosynthetic photon flux density SO - Photosynthetica. 39(2):275-281, 2001. AS - Photosynthetica 2001;39(2):275-281 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Carotenoids MH - Chlorophyll MH - Cultivar differences MH - Leaf conductance to water vapour MH - Rosa hybrida MH - Saccharides MH - Stomata. MH - Atmospheric co2 MH - Long-term MH - Electron-transport MH - Carbon-dioxide MH - Water-stress MH - Carboxylase oxygenase MH - Stomatal conductance MH - Net photosynthesis MH - Greenhouse roses MH - Quantum yield. AB - Gas exchange and chlorophyll (Chl) fluorescence were measured on young mature leaves of rose plants (Rosa hybrida cvs. First Red and Twingo) grown in two near-to-tight greenhouses, one under control ambient CO2 concentration, AC (355 mu mol mol(-1)) and one under CO2 enrichment, EC (700 mu mol mol(-1)), during four flushes from late June to early November. Supply of water and mineral elements was non-limiting while temperature was allowed to rise freely during daytime. Leaf diffusive conductance was not significantly reduced at EC but net photosynthetic rate increased by more than 100 %. Although the concentration of total non-structural saccharides was substantially higher in the leaves from the greenhouse with EC, Phi (PS2) (quantum efficiency of radiation use) around noon was not significantly reduced at EC indicating that there was no down-regulation of electron transport. Moreover, CO2 enrichment did not cause any increase in the risk of photo-damage, as estimated by the 1 - q(P) parameter. Non-photochemical quenching was even higher in the greenhouse with EC during the two summer flushes, when temperature and photosynthetic photon flux density (PPFD) were the highest. Hence rose photosynthesis benefits strongly from high concentrations of atmospheric CO2 at both high and moderate temperatures and PPFD. [References: 56] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Urban L Ctr Cooperat Int Rech Agron Dev, Stn Bassin Martin BP 180 F-97455 St Pierre France Ctr Cooperat Int Rech Agron Dev, Stn Bassin Martin F-97455 St Pierre France Inst Natl Rech Agron, Unite Rech Integree Hort F-06410 Biot France <23> UI - 491MJ-0019 DD - ISI Document Solution: 491MJ AU - Druta A MA - a.druta@uasm.moldnet.md RA - Druta A TI - Effect of long term exposure to high CO2 concentrations on photosynthetic characteristics of Prunus avium L. plants SO - Photosynthetica. 39(2):289-297, 2001. AS - Photosynthetica 2001;39(2):289-297 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll fluorescence MH - Compensation irradiance MH - Dry mass MH - Growth MH - Photochemical efficiency MH - Stomatal conductance MH - Sweet cherry. MH - Elevated co2 MH - Atmospheric co2 MH - Gas-exchange MH - Chlorophyll fluorescence MH - Growth MH - Leaves MH - Acclimation MH - Parameters MH - Biochemistry MH - Expression. AB - The effect of two elevated carbon dioxide concentrations, 700 mu mol(CO2) mol(-1) (C700) and 1400 mu mol(CO2) mol(-1) (C1400), on photosynthetic performances of 1-year-old Prunus avium L. plant was studied. Plants grown at C700 were characterised by increased net photosynthetic rate (P-N) as compared to those grown at C1400. Plant photosynthetic adjustment to C1400 resulted in 27 % higher P-N than in control at atmospheric CO2 concentration (C-a) at the beginning of the experiment (3-4 weeks) with a consequent decline to the end of the experiment. Thus, 1 400 mu mol(CO2) mol(-1) had short-term stimulatory effect on plant P-N. Both chlorophyll (Chl) a and b concentrations dramatically decreased during exposure to C1400. Compensation irradiance was increased by 57 % in C700 and by 87 % in C1400. Photochemical efficiency (phi) was affected by balloon environment, however, a clear stimulatory effect of C700 was detected. Opposite influence of both elevated CO2 concentrations on P-Nmax was established: slight increase by C700 (2.7 % at C-a), but considerable decrease by C1400 (63 % at C-a). Exposure to C700 enhanced compensation irradiance by 42 %, while C1400 by only 21 %. Either C700 or C1400 did not reduce stomatal conductance (g(s)). Leaf area per plant (LAR) was more stimulated by C700 than by C1400. High unit area leaf mass, specific leaf area, and dry matter accumulation in roots without affecting tissue density characterised plants grown in C1400. However, when considering the root: shoot ratio, these plants allocated less carbon to the roots than plants from others treatments. [References: 37] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Druta A State Agrarian Univ Moldova, Dept Bot & Plant Physiol Mircesti Str 44 Kishinev 2049 Moldova State Agrarian Univ Moldova, Dept Bot & Plant Physiol Kishinev 2049 Moldova <24> UI - 491MJ-0021 DD - ISI Document Solution: 491MJ AU - Shirke PA MA - pashirke@yahoo.com RA - Shirke PA TI - Leaf photosynthesis, dark respiration and fluorescence as influenced by leaf age in an evergreen tree, Prosopis juliflora SO - Photosynthetica. 39(2):305-311, 2001. AS - Photosynthetica 2001;39(2):305-311 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll fluorescence kinetics MH - Photochemical efficiency MH - Photosystem 2 MH - Transpiration rate MH - Water use efficiency. MH - Chlorophyll fluorescence MH - Electron-transport MH - Gas-exchange MH - Leaves MH - Photoinhibition MH - Forest MH - Co2 MH - Capacity MH - Turnover MH - Position. AB - P. juliflora trees produce leaves during two growth periods. The first cohort of leaves is produced during spring in cool conditions, while the second cohort is produced during monsoon under warm conditions. I studied photosynthetic characteristics of young, mature, and old leaves of the previous season (monsoon) in the spring season. Maximum net photosynthetic rate of a young leaf was lower than that of the mature and old leaves. The total CO2 fixed per day by the young leaves was just 36 % of that in the mature leaves while the old leaves fixed 76 % of that of the mature leaf. The total transpiration rate and water use efficiency (WUE) were similar in the mature and old leaves, while they were much lower in the young leaves. Dark respiration rate was maximal in the young leaves as compared to the mature and old leaves. About 92 % of the total CO2 fixed per day were respired by the young leaves. The diurnal fluorescence characteristics (DeltaF/F-m, q(p), and q(N)) of the young, mature, and old leaves showed that photochemical efficiency of photosystem 2 during midday decreased more in the young and old leaves than in the mature ones. However, the fluorescence characteristics showed that in all the three leaf types there was complete recovery of the photochemical efficiency at sunset from the midday depression. F-v/F-m in the young and mature leaves also confirmed this. Hence the young and old leaves were photosynthetically less efficient than mature leaves, but they were well adapted to withstand the harsh environmental conditions. [References: 22] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Shirke PA Natl Bot Res Inst Rana Pratap Marg Lucknow 226001 Uttar Pradesh India Natl Bot Res Inst Lucknow 226001 Uttar Pradesh India <25> UI - 491MJ-0022 DD - ISI Document Solution: 491MJ AU - Yordanova E AU - Georgieva K AU - Gorinova N AU - Yordanov Y MA - geneng@mtel.net RA - Yordanova E TI - Influence of the herbicide chlortoluron on photosynthetic activity in transgenic tobacco plants SO - Photosynthetica. 39(2):313-316, 2001. AS - Photosynthetica 2001;39(2):313-316 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll fluorescence MH - Photosystem 2 activity MH - Rat cytochrome p4501a1. MH - Cytochrome p450 oxidoreductase MH - Chlorophyll fluorescence MH - Fused enzyme MH - Resistant. AB - Photosynthetic activity of leaf disks from chlortoluron (2 mu mol per plant) treated and non-treated non-transgenic and trans,genic (PGF-6) tobacco plants was measured from 1 up to 21 d after treatment under greenhouse conditions. PGF-6 plants, expressing the fused rat cytochrome P4501A1/yeast reductase genes were used. PGF-6 plants were much more chlortoluron-resistant than control plants. In non-transgenic tobacco plants the electron transport flow to PQ pool was strongly inhibited 1 d after treatment with herbicide whereas it was still existing in PGF-6 plants although some reduction was observed. The quantum yield of photosystem 2 (Phi PS2) which is related to the quantum yield of whole-chain electron transfer was much more inhibited by chlortoluron than the primary PS2 photochemistry, measured by the ratio F-v/F-m, Lower PS2 activity was found for herbicide-treated non-transgenic plants up to the 9(th) day. Then it started to increase in both control and PGF-6 plants, but more rapidly in PGF-6 ones, and its values were near to the control level at the 21(st) d after chlortoluron treatment. [References: 19] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Yordanova E Inst Genet Engn BG-2232 Kostinbrod 2 Bulgaria Inst Genet Engn BG-2232 Kostinbrod 2 Bulgaria Bulgarian Acad Sci, Inst Plant Physiol BU-1113 Sofia Bulgaria <26> UI - 491MJ-0023 DD - ISI Document Solution: 491MJ AU - Csintalan Z AU - Tuba Z AU - Takacs Z AU - Laitat E MA - csintalan@fau.gau.hu RA - Csintalan Z TI - Responses of nine bryophyte and one lichen species from different microhabitats to elevated UV-B radiation SO - Photosynthetica. 39(2):317-320, 2001. AS - Photosynthetica 2001;39(2):317-320 PU - ACAD SCI CZECH REPUBLIC, INST EXPERIMENTAL BOTANY, NA KARLOVCE 1A, PRAGUE 6 CZ-160 00, CZECH REPUBLIC. URL: http://www.ueb.cas.cz/bp IS - 0300-3604 MH - Chlorophyll fluorescence induction MH - Desiccation tolerance MH - Fluorescence emission spectrum. MH - Chlorophyll fluorescence MH - Water-deficit MH - Leaves MH - Plants MH - Desiccation MH - Rehydration MH - Components MH - Tolerance MH - Emission MH - Defense. AB - Chlorophyll fluorescence parameters (F-v/F-m, R-Fd) of nine bryophyte and one lichen species were investigated after prolonged exposure to elevated UV-B radiation. The majority of the investigated bryophytes showed a prompt or inducible tolerance to increased U-V-B irradiation. Among the investigated species high degree of UV-tolerance coincides with strong desiccation tolerance. [References: 23] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Csintalan Z St Istvan Univ, Fac Agr & Environm Sci, Dept Bot & Plant Physiol Pater K U 1 H-2103 Godollo Hungary St Istvan Univ, Fac Agr & Environm Sci, Dept Bot & Plant Physiol H-2103 Godollo Hungary Fac Agr Sci, Unit Plant Biol B-5030 Gembloux Belgium <27> UI - 492YR-0031 DD - ISI Document Solution: 492YR AU - Ting CS AU - Rocap G AU - King J AU - Chisholm SW MA - chisholm@mit.edu RA - Chisholm SW TI - Phycobiliprotein genes of the marine photosynthetic prokaryote Prochlorococcus: evidence for rapid evolution of genetic heterogeneity SO - MICROBIOLOGY-SGM. 147(Part 11):3171-3182, 2001 Nov. AS - Microbiology-(UK) 2001 Nov;147(Part 11):3171-3182 PU - SOC GENERAL MICROBIOLOGY, MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AE, BERKS, ENGLAND. URL: http://www.socgenmicrobiol.org.uk/default.htm IS - 1350-0872 MH - Cyanobacteria MH - Light-harvesting complex MH - Phycoerythrin MH - Phylogeny MH - Relative rates of evolution. MH - Divinyl chlorophyll-a MH - Unicellular cyanobacteria MH - 2 strains MH - Phycoerythrins MH - Prochlorophytes MH - Substitutions MH - Sequences MH - Numbers MH - Origins MH - Dna. AB - Prochlorococcus is a major photosynthetic prokaryote in nutrient-limited, open ocean environments and an important participant in the global carbon cycle. This phototroph is distinct from other members of the cyanobacterial lineage to which it belongs because it utilizes a chlorophyll alpha (2)/b((2)) light-harvesting complex as its major antenna, instead of phycobilisomes. Recently, genes encoding the phycobiliprotein phycoerythrin were identified in several Prochlorococcus isolates, thus making it the only extant photosynthetic prokaryote to possess a chlorophyll alb antenna as well as phycobiliprotein genes. In order to understand the evolution of phycobiliproteins in this genus, the authors have sequenced the phycoerythrin genes of two isolates that are the most deeply branching in the Prochlorococcus lineage and share the highest degree of 16S rDNA sequence similarity to phycobilisome-containing marine Synechococcus. Sequence analyses suggest that within the Prochlorococcus lineage, the selective forces shaping the evolution of the phycoerythrin gene set have not been uniform. Although strains that are most closely related to marine Synechococcus possess genes (cpeB, cpeA) encoding both subunits of phycoerythrin, a more recently evolved strain is shown to cpeA and to possess a degenerate form of cpeB. Differences in phycoerythrin gene sequences between Prochlorococcus and Synechococcus appear to be consistent with a model of elevated mutation rates rather than relaxed selection. This suggests that although phycoerythrin is not a major constituent of the light-harvesting apparatus in Prochlorococcus, as it is in Synechococcus, the cpeB and cpeA genes are still under selection, albeit a different type of selection than in Synechococcus. The evolution of the Prochlorococcus light-harvesting antenna complex provides an important system for understanding the origins and scope of phylogenetic diversity in ocean ecosystems. [References: 38] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Chisholm SW MIT, Dept Biol 77 Massachusetts Ave Cambridge, MA 02139 USA MIT, Dept Biol Cambridge, MA 02139 USA MIT, Dept Civil & Environm Engn Cambridge, MA 02139 USA <28> UI - 492PM-0009 DD - ISI Document Solution: 492PM AU - Rae R AU - Hanelt D AU - Hawes I RA - Rae R TI - Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake SO - Marine & Freshwater Research. 52(7):1023-1032, 2001. AS - Mar. Freshw. Res 2001;52(7):1023-1032 PU - C S I R O PUBLISHING, 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA. URL: http://www.publish.csiro.au IS - 1323-1650 MH - Variable fluorescence MH - Photoinhibition MH - Uvr-absorbing compounds. MH - Solar ultraviolet-radiation MH - High light stress MH - Chlorophyll fluorescence MH - Amino-acids MH - Species composition MH - Chondrus-crispus MH - Photosystem-ii MH - South-island MH - B radiation MH - Short-term. AB - The ultraviolet radiation ( UVR) responses of photosynthesis by two freshwater vascular plants, Potamogeton cheesemanii and Isoetes alpinus, and the characean algae Chara fibrosa and C. corallina in Lake Coleridge, New Zealand, were investigated. Experiments comprised 4-5 h of exposure to different UV wavelengths followed by 17 h of recovery in low light. Photosynthetic competence was assessed by pulse-amplitude-modulated fluorometry. The four species showed different sensitivities to UVR, which were consistent with their upper depth limits. The shallowest-growing species, P. cheesemanii, was uninhibited by UVR, whereas after 5 h of exposure to UVR, inhibition of 15%, 38% and 48% was measured for I. alpinus, C. fibrosa and C. corallina collected from 4 m, 6.2 m and 16.5 m, respectively. Not all plants recovered fully from UVR inhibition. Plants from upper and lower depths of their growth range did not generally differ in inhibition sustained or ability to recover photosynthesis. The species with greatest tolerance of UVR also contained the highest concentrations of UVR-absorbing pigments. Freshwater macrophytes have differing abilities to tolerate UVR exposure through repair and or protection strategies and these may be related to their vertical zonation. [References: 43] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Aquatic Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Rae R Natl Inst Water & Atmospher Res POB 8602 Christchurch New Zealand Natl Inst Water & Atmospher Res Christchurch New Zealand Alfred Wegener Inst Polar & Marine Res D-27570 Bremerhaven Germany <29> UI - 491VZ-0028 DD - ISI Document Solution: 491VZ AU - Del Castillo CE AU - Coble PG AU - Conmy RN AU - Muller-Karger FE AU - Vanderbloemen L AU - Vargo GA RA - Del Castillo CE TI - Multispectral in situ measurements of organic matter and chlorophyll fluorescence in seawater: Documenting the intrusion of the Mississippi River plume in the West Florida Shelf SO - Limnology & Oceanography. 46(7):1836-1843, 2001 Nov. AS - Limnol. Oceanogr 2001 Nov;46(7):1836-1843 PU - AMER SOC LIMNOLOGY OCEANOGRAPHY, 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA IS - 0024-3590 MH - Orinoco-river MH - Optical-properties MH - Sea MH - Absorption MH - Spectra MH - Waters. AB - We performed multispectral, in situ fluorescence measurements of detrital colored organic matter (COM) and chlorophyll a (Chi a) in surface waters of the West Florida Shelf using the Wet Labs spectral absorption and fluorescence instrument (SAFIre). Continuous underway measurements allowed simultaneous mapping of the dispersal pattern of riverine organic material and Chl a on the shelf. We used two fluorescence emission ratios to differentiate between riverine and marine COM. The data showed unusually high concentrations of COM offshore. These were attributed to an offshore extension of the Mississippi River plume. Comparisons between in situ Chl a concentrations measured with the SAFIre and Chl a values obtained from the sea-viewing wide field-of-view sensor (SeaWiFS) satellite data using OC4 and MODIS algorithms showed that, although both algorithms overestimated Chi a, MODIS performed better than OC4, particularly in areas with high COM concentrations. Analysis of the relationship between Chl a and COM concentrations within the study area showed regional variability probably caused by differences in river source. [References: 28] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Aquatic Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Del Castillo CE NASA Code MA00 Bldg 1100 202-B Stennis Space Ctr, MS 39529 USA NASA Stennis Space Ctr, MS 39529 USA Univ S Florida, Coll Marine Sci St Petersburg, FL 33701 USA <30> UI - 492YW-0004 DD - ISI Document Solution: 492YW AU - Atsumi T MA - atsumi@npn.jst.jo.jp RA - Atsumi T TI - An ultrasonic motor model for bacterial flagellar motors SO - Journal of Theoretical Biology. 213(1):31-51, 2001 Nov 7. AS - J. Theor. Biol 2001 Nov 7;213(1):31-51 PU - ACADEMIC PRESS LTD, 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND. URL: http://www.apnet.com IS - 0022-5193 MH - Force-generating units MH - Salmonella-typhimurium MH - Escherichia-coli MH - Protonmotive force MH - Rotary motor MH - Vibrio-alginolyticus MH - Stochastic resonance MH - Energy transduction MH - Torque generation MH - Rotation rate. AB - A model for the transduction of energy occurring in bacterial flagellar motors is presented. In this model, the influx of ions across the channel causes the cyclic conformational change of the channel itself, which in turn produces travelling waves in one of the subcomponents of the motor, the C ring. This wave stabilizes the cyclical movement of the channel which generates the rotating force. The estimated frequency of cyclic conformational change is between 36 kHz and 6.3 MHz, i.e. in the ultrasonic range. This phenomenon is therefore referred to as the ultrasonic micromotor of microorganisms. (C) 2001 Academic Press. [References: 78] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Multidisciplinary in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Atsumi T ERATO, JST, Proton NanoMachine Project 1-7 Hikaridai Kyoto 6190237 Japan ERATO, JST, Proton NanoMachine Project Kyoto 6190237 Japan <31> UI - 493LL-0015 DD - ISI Document Solution: 493LL AU - Li JC AU - Zhao XH AU - Matsui S RA - Li JC TI - Hydrogen peroxide contents and activities of antioxidative enzymes among C-3, C-4 and CAM plants [Japanese] SO - Journal of the Japanese Society for Horticultural Science. 70(6):747-752, 2001 Nov. AS - J. Jpn. Soc. Hortic. Sci 2001 Nov;70(6):747-752 PU - JAPAN SOC HORTICULTURAL SCI, KYOTO UNIV, FACULTY AGRICULTURE, SAKYOKU, KYOTO, JAPAN IS - 0013-7626 MH - Antioxidative enzyme MH - C-3 MH - C-4 MH - Cam MH - Hydrogen peroxide. MH - Leaves MH - Oxygen MH - Chloroplasts MH - Stress MH - Cycle MH - Photoinhibition MH - Dissipation MH - Zeaxanthin MH - Catalase MH - Light. AB - Leaves of nine, seven and nine species, respectively, of C-3, C-4 and CAM plants, under usual growing conditions, were collected to determine H2O2 content and the activities of oxygen-scavenging enzymes. H2O2 content in leaves of C-4 plants was similar to that of C-3 plants, whereas that of CAM plants was higher. The superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) activities were higher in C-3 plants compared to those of CAM plants. C-4 plants exhibited higher APX but lower CAT activities than C-3 plants; however, both activities were higher than those of CAM plants. Our findings indicate that oxygen-scavenging systems in plants, such as those involving H2O2, differ from their photosynthetic capacities. [References: 22] LG - Japanese PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Li JC Gifu Univ, United Grad Sch Agr Sci Yanagido 1-1 Gifu 5011193 Japan Gifu Univ, United Grad Sch Agr Sci Gifu 5011193 Japan Gifu Univ, Fac Agr Gifu 5011193 Japan <32> UI - 490JR-0032 DD - ISI Document Solution: 490JR AU - O'Malley PJ AU - Collins SJ RA - O'Malley PJ TI - The effect of axial Mg ligation on the geometry and spin density distribution of chlorophyll and bacteriochlorophyll cation free radical models: A density functional study SO - Journal of the American Chemical Society. 123(44):11042-11046, 2001 Nov 7. AS - J. Am. Chem. Soc 2001 Nov 7;123(44):11042-11046 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.acs.org IS - 0002-7863 MH - Nuclear double-resonance MH - Triple-resonance MH - Primary donor MH - Reaction centers MH - Endor MH - Photosynthesis MH - Sphaeroides MH - Dimer. AB - Density functional calculations are performed on models of chlorophyll and bacterio chlorophyll to examine the effect of Mg ligation on the geometry and spin density distribution of the cation free radicals formed. It is shown that, whereas the properties of the bacteriochlorophyll model can be explained on the basis of the electron density distribution of the highest occupied molecular orbital (HOMO), for the chlorophyll model the geometry and spin density properties of the ligated species do not follow this trend. For the ligated chlorophyll models it is shown that, due to the closeness in energy of the HOMO and HOMO-1 orbitals, a Jahn-Teller distortion occurs on one-electron oxidation, leading to an admixed hybrid orbital for the cation radical form. Orbital mixing is shown to lead to significant changes in the geometry and spin density distribution of the cation free radical formed. It is also shown that orbital mixing does not lead to an increase in the magnitude of the N-14 hyperfine couplings thereby invalidating reports in the literature which have dismissed mixed orbital states for the primary donor cation radicals of photosynthetic reaction centers based on this criterion. [References: 20] LG - English PT - Article SB - Current Contents(R)/Life Sciences Current Contents(R)/Physical, Chemical & Earth Sciences CC - Chemistry & Analysis in Current Contents(R)/Life Sciences. Chemistry in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: O'Malley PJ Univ Manchester, Inst Sci & Technol, Dept Chem Manchester M60 1QD Lancs England Univ Manchester, Inst Sci & Technol, Dept Chem Manchester M60 1QD Lancs England <33> UI - 490JQ-0037 DD - ISI Document Solution: 490JQ AU - Hsu CP AU - Walla PJ AU - Head-Gordon M AU - Fleming GR RA - Fleming GR TI - The role of the S-1 state of carotenoids in photosynthetic energy transfer: The light-harvesting complex II of purple bacteria SO - Journal of Physical Chemistry B. 105(44):11016-11025, 2001 Nov 8. AS - J. Phys. Chem. B 2001 Nov 8;105(44):11016-11025 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.acs.org IS - 1089-5647 MH - Density-functional theory MH - Excitation-energies MH - Antenna complex MH - Rhodopseudomonas-acidophila MH - Rhodobacter-sphaeroides MH - To-bacteriochlorophyll MH - Femtosecond dynamics MH - Crystal-structure MH - Response theory MH - Lh2 complexes. AB - Using time-dependent density functional theory (TDDFT), we obtained the excitation energy transfer coupling (Coulombic coupling) between the S-1 state of rhodopin glucoside (RG) and the Q(y) state of bacteriochlorophylls (BCh1) in the light-harvesting complex II (LH2) of purple photosynthetic bacterium Rhodopseudomonas (Rps.) acidophila. Our results suggest that the small mixing of S-2 character arising from symmetry-breaking of the carotenoid plays an important role in the Coulombic coupling. As a result the carotenoid (car) S-1 couplings to chlorophylls are similar to a set of scaled down Car(S2)-BCh1(Q(y)) couplings. We also report results for 6,10,15,19-tetramethyl-2-cis-4,6,8,10,12,14,16,18,20-all trans-22-cis-tetracosaundecaene, the polyene backbone of RG with six methyl groups attached, in two different structures: an optimized planar structure and the crystal structure of RG with hydrogen atoms replacing the two end groups, which is distorted from its planar structure. The mixing of S-2 configuration is strictly forbidden in the planar structure due to symmetry. In this case the polyene still couples moderately strongly to the nearby BCh1s. In the distorted structure derived from RG crystal structure, coupling strengths and the role of S-2 character mixing are similar to those of the full RG. Using an exciton model simulation, the calculated coupling strengths yield Car(S-1)-to-BCh1(Q(y)) excitation energy transfer times that are in good agreement with recent experimental results. [References: 57] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Physical Chemistry/Chemical Physics in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Fleming GR Univ Calif Berkeley, Dept Chem Berkeley, CA 94720 USA Univ Calif Berkeley, Dept Chem Berkeley, CA 94720 USA Lawrence Berkeley Natl Lab, Div Chem Sci Berkeley, CA 94720 USA Lawrence Berkeley Natl Lab, Phys Biosci Div Berkeley, CA 94720 USA <34> UI - 493DE-0016 DD - ISI Document Solution: 493DE AU - Zigmantas D AU - Polivka T AU - Hiller RG AU - Yartsev A AU - Sundstrom V MA - villy.sundstrom@chemphys.lu.se RA - Sundstrom V TI - Spectroscopic and dynamic properties of the peridinin lowest singlet excited states SO - Journal of Physical Chemistry. 105(45):10296-10306, 2001 Nov 15. AS - J. Phys. Chem. A 2001 Nov 15;105(45):10296-10306 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.acs.org IS - 1089-5639 MH - Chlorophyll-protein complexes MH - Energy-transfer MH - Amphidinium-carterae MH - Internal-conversion MH - Solvent dependence MH - Beta-carotene MH - A protein MH - S-1 state MH - Bacteriochlorophyll MH - Photosynthesis. AB - Spectroscopic properties as well as excited state dynamics of the carotenoid peridinin in several solvents of different polarities were investigated by time-resolved fluorescence and transient absorption techniques. A strong dependence of the peridinin lowest excited states dynamics on solvent polarity was observed after excitation into the strongly allowed S-2 state. Peridinin relaxes to the ground state within 10 ps in the strongly polar solvent methanol, while in the nonpolar solvent n-hexane a 160 ps lifetime was observed, thus confirming the previous observations revealed by transient absorption spectroscopy in the visible region (Bautista, J. A.; et al. J. Phys. Chem. B 1999, 103, 8751). In addition, the solvent dependence in the near-IR region is demonstrated by a strong negative feature in the transient absorption spectrum of peridinin in methanol, which is not present in n-hexane. This band, characterized by a 1 ps rise time, is ascribed to stimulated emission from an intramolecular charge-transfer (ICT) state. Time-resolved fluorescence data support assignment of this band to the emissive singlet state, whose dynamic characteristics depend strongly on the dielectric strength of the medium. On the basis of all our time-resolved measurements combined with simulations of the observed kinetics, we propose the following model: the initially populated S-2 state decays to the S-1 state within less than 100 fs for both solvents. Then, the population is transferred from the S-1 state to the S-0 and ICT states. The S1 --> ICT transfer is controlled by a solvent polarity dependent barrier. In n-hexane the barrier is high enough to prevent the S-1 --> ICT transfer and only S-1 --> S-0 relaxation characterized by a time constant of 160 ps is observed. An increase of solvent polarity leads to a significant decrease of the barrier, enabling a direct quenching of the S-1 state by means of the S-1 --> ICT transfer, which is characterized by a time constant of 148 ps for tetrahydrofuran, 81 ps for 2-propanol, and 11 ps for the most polar solvent methanol. The ICT state is then rapidly depopulated to the ground state. This relaxation also exhibits solvent dependence, having a time constant of 1 ps in methanol, 2.5 ps in 2-propanol, and 3.5 ps in tetrahydrofuran. [References: 38] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Physical Chemistry/Chemical Physics in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Sundstrom V Lund Univ, Dept Chem Phys Box 124 S-22100 Lund Sweden Lund Univ, Dept Chem Phys S-22100 Lund Sweden Macquarie Univ, Dept Biol Sci N Ryde NSW 2109 Australia <35> UI - 490NA-0009 DD - ISI Document Solution: 490NA AU - Iida A AU - Saito S AU - Sekine A AU - Mishima C AU - Kondo K AU - Kitamura Y AU - Harigae S AU - Osawa S AU - Nakamura Y MA - yusuke@ims.u-tokyo.ac.jp RA - Nakamura Y TI - Catalog of 258 single-nucleotide polymorphisms (SNPs) in genes encoding three organic anion transporters, three organic anion-transporting polypeptides, and three NADH : ubiquinone oxidoreductase flavoproteins SO - Journal of Human Genetics. 46(11):668-683, 2001. AS - J. Hum. Genet 2001;46(11):668-683 PU - SPRINGER-VERLAG TOKYO, 3-3-13, HONGO, BUNKYO-KU, TOKYO, 113, JAPAN IS - 1434-5161 MH - Single-nucleotide polymorphisms (snps) MH - High-density snp map MH - Nonsynonymous substitutions MH - Insertion-deletion polymorphism MH - Japanese population MH - Human organic-anion transporter genes MH - Human organic anion-transporting polypeptide genes MH - Nadh : ubiquinone oxidoreductase flavoprotein genes. MH - Mitochondrial complex-i MH - Human liver MH - Functional-characterization MH - Molecular-cloning MH - 51-kda subunit MH - Identification MH - Family MH - Localization MH - Disease MH - Ndufv1. AB - We present here a series of high-density maps of single-nucleotide polymorphisms (SNPs) detected in genes encoding three organic-anion transporters, three organic anion-transporting polypeptides, and three nicotinamide adenine dinucleotide. reduced:ubiquinone oxidoreductase flavoproteins. A total of 258 SNPs were identified among these nine genes through systematic screening of DNA from 48 Japanese individuals: 17 in 5' flanking regions, three in 5' untranslated regions, 13 in coding regions, 211 in introns, six in 3' untranslated regions, and 8 in 3' flanking regions. By comparing our data with SNPs deposited in the dbSNP database in the National Center for Biotechnology Information, we determined that 236 (91.5%) were novel. In addition, 46 genetic variations of other types were discovered within these loci. These high-resolution maps will serve as a useful resource for analyzing potential associations between variations in these nine genes and differences in human susceptibilities to common diseases or response to drug therapies. [References: 31] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Molecular Biology & Genetics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Nakamura Y Univ Tokyo, Inst Med Sci, Ctr Human Genome, Mol Med Lab,Minato Ku 4-6-1 Shirokanedai Tokyo 1088639 Japan Univ Tokyo, Inst Med Sci, Ctr Human Genome, Mol Med Lab,Minato Ku Tokyo 1088639 Japan RIKEN SNP Res Ctr, Lab Genotyping Tokyo Japan <36> UI - 492PN-0002 DD - ISI Document Solution: 492PN AU - Lisdiyanti P AU - Kawasaki H AU - Seki T AU - Yamada Y AU - Uchimura T AU - Komagata K MA - 38990006@nodai.ac.jp RA - Lisdiyanti P TI - Identification of Acetobacter strains isolated from Indonesian sources, and proposals of Acetobacter syzygii sp nov., Acetobacter cibinongensis sp nov., and Acetobacter orientalis sp nov. SO - Journal of General & Applied Microbiology. 47(3):119-131, 2001 Jun. AS - J. Gen. Appl. Microbiol 2001 Jun;47(3):119-131 PU - MICROBIOL RES FOUNDATION, JAPAN ACADEMIC SOC CENTER BLDG 4-16 YAYOI 2-CHOME, TOKYO, TOKYO 113, JAPAN IS - 0022-1260 MH - Acetobacter MH - Acetobacter cibinongensis MH - Acetobacter orientalis MH - Acetobacter syzygii MH - Distribution of acetobacter strains in indonesia. MH - Acetic-acid bacterium MH - Genus MH - Proteobacteria MH - Gluconobacter. AB - Forty-six strains of acetic acid bacteria newly isolated from flowers, fruits, and fermented foods collected in Indonesia were taxonomically studied. They were Gram-negative rods, produced acetic acid from ethanol, oxidized acetate and lactate to CO2 and H2O, and had 0-9 as the major ubiquinone system. On the basis of DNA-DNA similarity, all strains studied, including type strains and reference strains of the genus Acetobacter, were separated into eleven groups (Groups I to XI). Of the 46 isolates, two isolates were included in Group II and identified as Acetobacter pasteurianus, five in Group IV as A. orleanensis, 16 in Group V as A. lovaniensis, five in Group VII as A. indonesiensis, and three in Group VIII as A. tropicalis. The remaining 15 isolates constituted three new groups based on DNA-DNA similarity; four isolates were included in Group IX, two in Group X, and nine in Group XI. No isolates were identified as A. aceti (Group I), A. peroxydans (Group III), and A. estunensis (Group VI). Phylogenetic analysis based on 16S rDNA sequences of representative strains of the Groups indicated belonging to the strains of the genus Acetobacter. On the basis of DNA base composition, DNA-DNA similarity, and 16S rDNA sequences, three new species of the genus Acetobacter are proposed: Acetobacter syzygii sp. nov. for Group IX, Acetobacter cibinongensis sp. nov. for Group X, and Acetobacter orientalis sp. nov. for Group XI. The distribution of Acetobacter strains in Indonesia is discussed in light of isolation sources. [References: 15] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Lisdiyanti P Tokyo Univ Agr, Fac Appl Biosci, Dept Appl Biol & Chem, Lab Gen & Appl Microbiol,Setagaya Ku 1-1-1 Sakuragaoka Tokyo 1568502 Japan Tokyo Univ Agr, Fac Appl Biosci, Dept Appl Biol & Chem, Lab Gen & Appl Microbiol,Setagaya Ku Tokyo 1568502 Japan Osaka Univ, Int Ctr Biotechnol Suita Osaka 5650871 Japan <37> UI - 492LF-0044 DD - ISI Document Solution: 492LF AU - Bibby TS AU - Nield J AU - Barber J MA - j.barber@ic.ac.uk RA - Barber J TI - Three-dimensional model and characterization of the iron stress-induced CP43 '-photosystem I supercomplex isolated from the cyanobacterium Synechocystis PCC 6803 SO - Journal of Biological Chemistry. 276(46):43246-43252, 2001 Nov 16. AS - J. Biol. Chem 2001 Nov 16;276(46):43246-43252 PU - AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA. URL: http://www-jbc.stanford.edu/jbc IS - 0021-9258 MH - Photosynthetic reaction-center MH - Equatorial pacific-ocean MH - Anacystis-nidulans r2 MH - Photosystem-ii MH - Synechococcus sp MH - Angular reconstitution MH - Chlorophyll-protein MH - Isia gene MH - Resolution MH - Complex. AB - The cyanobacterium Synechocystis PCC 6803 has been subjected to growth under iron-deficient conditions. As a consequence, the isiA gene is expressed, and its product, the chlorophyll a-binding protein CP43', accumulates in the cell. Recently, we have shown for the first time that 18 copies of this photosystem II (PSII)-like chlorophyll a-binding protein forms a ring around the trimeric photosystem I (PSI) reaction center (Bibby, T. S., Nield, J., and Barber, J. (2001) Nature, 412, 743-745). Here we further characterize the biochemical and structural properties of this novel CP43'-PSI supercomplex confirming that it is a functional unit of approximately 1900 kDa where the antenna size of PSI is increased by 70% or more. Using electron microscopy and single particle analysis, we have constructed a preliminary three-dimensional model of the CP43'-PSI supercomplex and used it as a framework to incorporate higher resolution structures of PSI and CP43 recently derived from x-ray crystallography. Not only does this work emphasize the flexibility of cyanobacterial light-harvesting systems in response to the lowering of phycobilisome and PSI levels under iron-deficient conditions, but it also has implications for understanding the organization of the related chlorophyll a/b-binding Pcb proteins of oxychlorobacteria, formerly known as prochlorophytes. [References: 40] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Barber J Univ London Imperial Coll Sci Technol & Med, Dept Biol Sci, Wolfson Labs London SW7 2AY England Univ London Imperial Coll Sci Technol & Med, Dept Biol Sci, Wolfson Labs London SW7 2AY England <38> UI - 490WC-0015 DD - ISI Document Solution: 490WC AU - Ichikawa N AU - Karaki A AU - Kawabata M AU - Ushida S AU - Mizushima M AU - Hashimoto T MA - ichikawa@life.osaka-cu.ac.jp RA - Ichikawa N TI - The region from phenylalanine-17 to phenylalanine-28 of a yeast mitochondrial ATPase inhibitor is essential for its ATPase inhibitory activity SO - Journal of Biochemistry. 130(5):687-693, 2001 Nov. AS - J. Biochem. (Tokyo) 2001 Nov;130(5):687-693 PU - JAPANESE BIOCHEMICAL SOC, ISHIKAWA BLDG-3F, 25-16 HONGO-5-CHOME, BUNKYO-KU, TOKYO, 113, JAPAN. URL: http://www.bcasj.or.jp/jb/jbshome/jbs-home.html IS - 0021-924X MH - Atpase inhibitor (if1) MH - Atp synthase MH - F1f0-atpase MH - Mitochondria MH - Regulation. MH - Amino-acid-sequence MH - Adenosine-triphosphatase inhibitor MH - Protein inhibitor MH - Heart-mitochondria MH - Synthase MH - Binding MH - Ph MH - F1-atpase MH - Cloning MH - Complex. AB - Mitochondrial ATP synthase (F1F0-ATPase) is regulated by an intrinsic ATPase inhibitor protein. In the present study, we investigated the structure-function relationship of the yeast ATPase inhibitor by amino acid replacement. A total of 22 mutants were isolated and characterized. Five mutants (F17S, R20G, R22G, E25A, and F28S) were entirely inactive, indicating that the residues, Phe17, Arg20, Arg22, Glu25, and Phe28, are essential for the ATPase inhibitory activity of the protein. The activity of 7 mutants (A23G, R30G, R32G, Q36G, L37G, L40S, and L44G) decreased, indicating that the residues, Ala23, Arg30, Arg32, Gln36, Leu37, Leu40, and Leu44, are also involved in the activity. Three mutants, V29G, K34Q, and K41Q, retained normal activity at pH 6.5, but were less active at pH 7.2, indicating that the residues, Val29, Lys34, and Lys41, are required for the protein's action at higher pH. The effects of 6 mutants (D26A, E35V, H39N, H39R, K46Q, and K49Q) were slight or undetectable, and the residues Asp26, Glu35, His39, Lys46, and Lys49 thus appear to be dispensable. The mutant E21A retained normal ATPase inhibitory activity but lacked pH-sensitivity. Competition experiments suggested that the 5 inactivated mutants (F17S, R20G, R22G, E25A, and F28S) could still bind to the inhibitory site on F1F0-ATPase. These results show that the region from the position 17 to 28 of the yeast inhibitor is the most important for its activity and is required for the inhibition of F-1, rather than binding to the enzyme. [References: 32] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Ichikawa N Osaka City Univ, Fac Human Life Sci, Dept Food & Nutr 3-3-138 Sugimoto Osaka 5588585 Japan Osaka City Univ, Fac Human Life Sci, Dept Food & Nutr Osaka 5588585 Japan Muroran Inst Technol, Dept Appl Chem Muroran Hokkaido 0508585 Japan <39> UI - 492FW-0026 DD - ISI Document Solution: 492FW AU - Bertsova YV AU - Bogachev AV AU - Skulachev VP MA - skulach@head.genebee.msu.su RA - Skulachev VP TI - Noncoupled NADH : ubiquinone oxidoreductase of Azotobacter vinelandii is required for diazotrophic growth at high oxygen concentrations SO - Journal of Bacteriology. 183(23):6869-6874, 2001 Dec. AS - J. Bacteriol 2001 Dec;183(23):6869-6874 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Cytochrome-bd MH - Terminal oxidase MH - Respiratory protection MH - Up-regulation MH - Mutagenesis MH - Nitrogen MH - Fixation MH - Mutants MH - Transformation MH - Genes. AB - The gene encoding the noncoupled NADH:ubiquinone oxidoreductase (NDH II) from Azotobacter vinelandii was cloned, sequenced, and used to construct an NDH II-deficient mutant strain. Compared to the wild type, this strain showed a marked decreased in respiratory activity. It was unable to grow diazotrophically at high aeration, while it was fully capable of growth at low aeration or in the presence of NH4+. This result suggests that the role of NDH II is as a vital component of the respiratory protection mechanism of the nitrogenase complex in A. vinelandii. It was also found that the oxidation of NADPH in the A. vinelandii respiratory chain is catalyzed solely by NDH II. [References: 26] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Skulachev VP Moscow MV Lomonosov State Univ, Dept Bioenerget, AN Belozersky Inst Physicochim Biol Moscow 119899 Russia Moscow MV Lomonosov State Univ, Dept Bioenerget, AN Belozersky Inst Physicochim Biol Moscow 119899 Russia <40> UI - 492FW-0029 DD - ISI Document Solution: 492FW AU - Oh JI AU - Ko IJ AU - Kaplan S MA - samuel.kaplan@uth.tmc.edu RA - Kaplan S TI - The default state of the membrane-localized histidine kinase PrrB of Rhodobacter sphaeroides 2.4.1 is in the kinase-positive mode SO - Journal of Bacteriology. 183(23):6807-6814, 2001 Dec. AS - J. Bacteriol 2001 Dec;183(23):6807-6814 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Photosynthesis gene-expression MH - 2-component regulatory system MH - Signal-transduction system MH - Gram-negative bacteria MH - Rhodobacter-sphaeroides-2.4.1 MH - Capsulatus MH - Mutant MH - Complementation MH - Fixation MH - Protein. AB - The PrrBA two-component activation system of Rhodobacter sphaeroides plays a major role in the induction of photosynthesis gene expression under oxygen-limiting or anaerobic conditions. The PrrB histidine kinase is composed of two structurally identifiable regions, the conserved C-terminal kinase/phosphatase domain and the N-terminal membrane-spanning domain with six transmembrane helices framing three periplasmic and two cytoplasmic loops. Using a set of PrrB mutants with lesions in the transmembrane domain, we demonstrate that the central portion of the PrrB transmembrane domain including the second periplasmic loop plays an important role in both sensing and signal transduction. Signal transduction via the transmembrane domain is ultimately manifested by controlling the activity of the C-terminal kinase/phosphatase domain-The extent of signal transduction is determined by the, ability of the transmembrane domain to sense the strength of the inhibitory signal received from the ebb, terminal oxidase (J.-I Oh, and S. Kaplan, EMBO J. 19:4237-4247, 2000). Therefore, the intrinsic ("default") state of PrrB is in the kinase-dominant mode. It is also demonstrated that the extent of prrB gene expression is subject to the negative autoregulation of the PrrBA system. [References: 33] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Kaplan S Univ Texas, Hlth Sci Ctr, Sch Med, Dept Microbiol & Mol Genet 6431 Fannin Houston, TX 77030 USA Univ Texas, Hlth Sci Ctr, Sch Med, Dept Microbiol & Mol Genet Houston, TX 77030 USA <41> UI - 492DK-0013 DD - ISI Document Solution: 492DK AU - Laney SR AU - Letelier RM AU - Desiderio RA AU - Abbott MR AU - Kiefer DA AU - Booth CR MA - sam@hawkeye.dmc.maine.edu RA - Laney SR TI - Measuring the natural fluorescence of phytoplankton cultures SO - Journal of Atmospheric & Oceanic Technology. 18(11):1924-1934, 2001. AS - J. Atmos. Ocean. Technol 2001;18(11):1924-1934 PU - AMER METEOROLOGICAL SOC, 45 BEACON ST, BOSTON, MA 02108-3693 USA IS - 0739-0572 MH - Biooptical drifters MH - Chlorophyll-a MH - Photosynthesis MH - Pacific MH - Scales MH - Ocean MH - Sea. AB - A laboratory instrument, the Natural Fluorescence Chemostat, was developed to measure the natural fluorescence of phytoplankton cultures. With this instrument, the physical and chemical environment of a culture can be manipulated with respect to temperature, pH, nutrient delivery rate, and light intensity, while the natural fluorescence and a weak stimulated fluorescence are continuously recorded with high temporal resolution. The geometry and spectral distribution of the artificial light field minimize the contribution of scattering to the natural fluorescence signal. Preliminary investigations with the marine diatom T. weissflogii (Bacillariophyceae) indicate that the instrument can detect natural fluorescence signals in broadband artificial light fields as bright as 1250 mmol quanta m(-2) s(-1). Since the influence of environmental factors on natural fluorescence is not well understood, laboratory experiments are essential for investigating how ocean physics and chemistry influence this signal. This instrument provides a quantitative means to examine how the magnitude and kinetics of phytoplankton natural fluorescence vary in response to changes in the physical and chemical environment. [References: 19] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Earth Sciences in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Laney SR Univ Maine, Darling Marine Ctr 193 Clarks Cove Rd Walpole, ME 04573 USA Oregon State Univ, Coll Ocean & Atmospher Sci Corvallis, OR 97331 USA Univ So Calif, Dept Biol Sci San Diego, CA USA Biospher Inc San Diego, CA USA <42> UI - 492RM-0003 DD - ISI Document Solution: 492RM AU - Agondanou JH AU - Spyroulias GA AU - Purans J AU - Tsikalas G AU - Souleau C AU - Coutsolelos AG AU - Benazeth S MA - coutsole@chemistry.uoc.gr RA - Coutsolelos AG TI - XAFS study of gadolinium and samarium bisporphyrinate complexes SO - Inorganic Chemistry. 40(24):6088-6096, 2001 Nov 19. AS - Inorg. Chem 2001 Nov 19;40(24):6088-6096 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.acs.org IS - 0020-1669 MH - X-ray-absorption MH - Photosynthetic reaction center MH - Porphyrin sandwich complexes MH - Tetrapyrrole ligands MH - Metal-complexes MH - Fine-structure MH - Double-deckers MH - Rhodopseudomonas-viridis MH - Deprotonated forms MH - Redox potentials. AB - The comparative X-ray absorption spectroscopy study of gadolinium and samarium bisporphyrinate complexes represented by the formulas (GdH)-H-III(oep)(tpp), Gd-III(oep)(2), (GdH)-H-III(tpp)(2) and (SmH)-H-III(oep)(tpp), Sm-III(oep)(2), (SmH)-H-III(tpp)(2) is reported. The XAFS spectra are recorded on the LURE-DCI storage ring (Orsay, France) in transmission mode on the microcrystalline samples at the Gd and Sin L-3 edges. The local environment for Ln(3+) ions has been reconstructed applying one-shell and two-shell XAFS analysis procedures. The protonated and nonprotonated bisporphyrinate complexes present different XAFS features. After our analysis on the title derivatives, the gadolinium ion (at 80 K) is found to be bonded: (i) to eight nitrogen atoms at R(Gd-N) 2.50 Angstrom, for (GdH)-H-III(oep)(2) [Debye-Waller (DW) factor 0.004 Angstrom (2)]; (ii) to Seven nitrogen atoms at R(Gd-N) 2.49 Angstrom, for (GdH)-H-III(oep)(tpp) [DW factor 0.005 Angstrom (2)] and one nitrogen at long distance; and (iii) to six nitrogen atoms at R(Gd-N) 2.50 Angstrom [DW factor 0.006 Angstrom (2)] and two nitrogen atoms at Iona distance for (GdH)-H-III(tpp)(2). A similar coordination sphere has been detected for the corresponding Sm derivatives. So, the samarium ion (at room temperature) is bonded: (i) to eight nitrogen atoms at R(Sm-N) 2.53 Angstrom, for Sm-III(oep)(2) [DW factor 0.006 Angstrom (2)]; (ii) to seven nitrogen atoms at R(Sm-N) 2.53 Angstrom, for (SmH)-H-III(oep)(tpp) [DW factor 0.006 Angstrom (2)] and one nitrogen at long distance; and (iii) to six nitrogen atoms at R(Sm-N) 2.50 Angstrom, for (SmH)-H-III(tpp)(2) [DW factor 0.006 Angstrom (2)] and two nitrogen atoms at long distance. As far as concerns Ln(III)(oep)(2) complexes, the increase of Ln-N distance in the series Gd3+ < Eu3+ < Sm3+ reflects an increase in the ionic radii, which are in good agreement with previously published XRD data on Eu-III(oep)(2). Moreover, the protonated, Ln(III)H(oep)(tpp) and Ln(III)H(tpp)(2) complexes possess systematically shorter distances of about 0.02 Angstrom between the XAFS and XRD data. This difference is attributed to the asymmetry of the distribution concerning Ln-N distances. [References: 46] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Inorganic & Nuclear Chemistry in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Coutsolelos AG Univ Paris 11, UFR Pharm, EA401, Lab Chim Phys Minerale & Bioinorgan F-92296 Chatenay Malabry France Univ Paris 11, UFR Pharm, EA401, Lab Chim Phys Minerale & Bioinorgan F-92296 Chatenay Malabry France Univ Crete, Dept Chem, Lab Bioinorgan Coordinat Chem GR-71409 Iraklion Crete Greece Univ Paris 05, Fac Pharm, Lab Biomath F-75006 Paris France Ctr Univ Paris XI, LURE F-91405 Orsay France Latvian State Univ, Inst Solid State Phys LV-1063 Riga Latvia <43> UI - 490JV-0019 DD - ISI Document Solution: 490JV AU - Maki DS AU - Colombo SJ MA - steve.colombo@mnr.gov.on.ca RA - Colombo SJ TI - Early detection of the effects of warm storage on conifer seedlings using physiological tests SO - Forest Ecology & Management. 154(1-2):237-249, 2001 Nov 15. AS - For. Ecol. Manage 2001 Nov 15;154(1-2):237-249 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0378-1127 MH - Chlorophyll fluorescence MH - Electrolyte leakage MH - Ethanol MH - Root growth potential MH - Seedling quality MH - Temperature. MH - Stock quality assessment MH - Chlorophyll fluorescence MH - Stress MH - Photoinhibition MH - Tolerance MH - Ontario MH - Spruce MH - Damage. AB - Four species of conifer seedlings were more tolerant of pre-planting within-package warm storage than suggested by the literature and physiological tests were highly predictive of incipient damage and growth potential. Bareroot white pine (Pinus strobus L.), red pine (Pinus resinosa Ail.), white spruce (Picea glauca (Moench.) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) seedlings in sealed polyethylene bags were stored at 15 degreesC from 5 to 13 days or at 30 degreesC from 12 h to 4 days. Seedling performance potential was evaluated after warm storage based on height increment, survival, and foliar damage in a 7-week greenhouse growth trial. White pine, white spruce, and black spruce seedlings were unaffected by storage at 15 degreesC storage for up to 13 days whereas red pine tolerated up to 5 days storage at 15 degreesC without damage or loss of growth. Red pine, black spruce, and white spruce could tolerate at least 12 h storage at 30 degreesC with no appreciable loss of performance potential while white pine suffered impairment even with the shortest period of storage (12 h) at 30 degreesC. The survival and growth of seedlings was accurately predicted by within-package ethanol concentration, shoot tip electrolyte leakage, chlorophyll fluorescence, and root growth potential. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 31] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Colombo SJ Ontario Forest Res Inst 1235 Queen St E Sault St Marie ON P6A 2E5 Canada Ontario Forest Res Inst Sault St Marie ON P6A 2E5 Canada <44> UI - 491FM-0017 DD - ISI Document Solution: 491FM AU - Fukuda E AU - Kino H AU - Matsuzawa H AU - Wakagi T MA - atwakag@mail.ecc.u-tokyo.ac.jp RA - Wakagi T TI - Role of a highly conserved YPITP motif in 2-oxoacid : ferredoxin oxidoreductase - Heterologous expression of the gene from Sulfolobus sp strain 7, and characterization of the recombinant and variant enzymes SO - European Journal of Biochemistry. 268(21):5639-5646, 2001 Nov. AS - Eur. J. Biochem 2001 Nov;268(21):5639-5646 PU - BLACKWELL SCIENCE LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0014-2956 MH - Archaea MH - Ferredoxin MH - Oxidoreductase MH - Pyruvate MH - Themophile. MH - Desulfovibrio-africanus MH - Rhodospirillum-rubrum MH - Trichomonas-vaginalis MH - Electron-transport MH - Nitrogen-fixation MH - Escherichia-coli MH - Citrate synthase MH - Pyruvate MH - Purification MH - Sequence. AB - 2-Oxoacid:ferredoxin oxidoreductase from Sulfolobus sp. strain 7, an aerobic and thermoacidophilic crenoarchaeon, catalyses the coenzyme A-dependent oxidative decarboxylation of pyruvate and 2-oxoglutarate, a cognate Zn-7Fe-ferredoxin serving as an electron acceptor. It comprises two subunits, a (632 amino acids) and b (305 amino acids). To further elucidate its structure and function, we constructed a gene expression system. The wild-type recombinant enzyme was indistinguishable from the natural one in every criterion investigated. A series of variants was constructed to elucidate the role of the YPITP-motif (residues 253-257) in subunit a, which is conserved universally in the 2-oxoacid:ferredoxin oxidoreductase (OFOR) family. Single amino-acid replacements at Y253 and P257 by other amino acids caused a drastic loss of enzyme activity. T256, the hydroxyl group of which has been proposed to be essential for binding of the 2-oxo group of the substrate in the Desulfovibrio africanus enzyme, was unexpectedly replaceable with Ala, the k(cat) and K-m for 2-oxoglutarate being approximate to 33% and approximate to 51%, respectively, as compared with that of the wild-type enzyme. Replacement at other positions resulted in a significant decrease in the k(cat) of the reaction while the Km for 2-oxoacid was only slightly affected. Thus, the YPITP-motif is essential for the turnover of the reaction rather than the affinity toward 2-oxoacid. [References: 40] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Wakagi T Univ Tokyo, Dept Biotechnol, Bunkyo Ku 1-1-1 Yayoi Cho Tokyo 1138657 Japan Univ Tokyo, Dept Biotechnol, Bunkyo Ku Tokyo 1138657 Japan Aomori Univ, Dept Biosci & Biotechnol Kohbata Japan <45> UI - 491HY-0032 DD - ISI Document Solution: 491HY AU - Moolenaar GF AU - Hoglund L AU - Goosen N MA - N.Goosen@chem.leidenuniv.nl RA - Goosen N TI - Clue to damage recognition by UvrB: residues in the beta-hairpin structure prevent binding to non-damaged DNA SO - EMBO Journal. 20(21):6140-6149, 2001 Nov 1. AS - Embo J 2001 Nov 1;20(21):6140-6149 PU - OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND. URL: http://www.oup.co.uk IS - 0261-4189 MH - Damage recognition MH - Dna repair MH - Nucleotide flipping MH - Uvrb. MH - Nucleotide excision-repair MH - Coli uvrabc endonuclease MH - Escherichia-coli MH - Crystal-structure MH - Protein complex MH - Thermus-thermophilus MH - Preincision complex MH - (a)bc excinuclease MH - Helicase MH - Mechanism. AB - UvrB, the ultimate damage-recognizing component of bacterial nucleotide excision repair, contains a flexible beta -hairpin rich in hydrophobic residues. We describe the properties of UvrB mutants in which these residues have been mutated. The results show that Y101 and F108 in the tip of the hairpin are important for the strand-separating activity of UvrB, supporting the model that the beta -hairpin inserts between the two DNA strands during the search for DNA damage. Residues Y95 and Y96 at the base of the hairpin have a direct role in damage recognition and are positioned close to the damage in the UvrB-DNA complex. Strikingly, substituting Y92 and Y93 results in a protein that is lethal to the cell. The mutant protein forms pre- incision complexes on non-damaged DNA, indicating that Y92 and Y93 function in damage recognition by preventing UvrB binding to non-damaged sites. We propose a model for damage recognition by UvrB in which, stabilized by the four tyrosines at the base of the hairpin, the damaged nucleotide is flipped out of the DNA helix. [References: 33] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Molecular Biology & Genetics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Goosen N Leiden Univ, Gorlaeus Labs, Leiden Inst Chem, Genet Mol Lab Einsteinweg 55 NL-2300 RA Leiden Netherlands Leiden Univ, Gorlaeus Labs, Leiden Inst Chem, Genet Mol Lab NL-2300 RA Leiden Netherlands <46> UI - 493GX-0008 DD - ISI Document Solution: 493GX AU - Zhao JQ AU - Zou YL AU - Liu BH AU - Peng XS AU - Xu CH AU - Kong JL RA - Kong JL TI - Studies on the electron transfer for reaction center isolated from Rhodobacter sphaeroides in self-assembly composite film [Chinese] SO - Chemical Journal of Chinese Universities-Chinese. 22(9):1486-1491, 2001 Sep. AS - Chem. J. Chin. Univ.-Chin 2001 Sep;22(9):1486-1491 PU - HIGHER EDUCATION PRESS, SHATANHOU ST 55, BEIJING 100009, PEOPLES R CHINA. URL: http://www.hep.edu.cn IS - 0251-0790 MH - Electron transfer MH - Electrochemistry MH - Rhodobacter sphaeroides MH - Reaction center. MH - Photosynthetic reaction centers MH - Acceptor. AB - The composite ordered protein film was assemblied on the surface of a gold electrode by self-assembly mono-layer approach using meso-2, 3-dimercaptosuccinic acid (DMSA), poly-dimethyldiallylammonium chloride (PDDA) and reaction center membrane protein purified from purple bacteria (Rhodobacter sphaeroides). Square wave voltammetry(SWV) was employed to study the electrochemical behavior of the protein composite film. The reversible or quasi-reversible electron transfer for redox couples therein was successfully detected. The reduction potential for each redox couple and the electrochemically-driven effect was also discussed. The typical SWV results were non-linearly fitted to get the kinetic parameters for the composite protein film. [References: 17] LG - Chinese PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Chemistry in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2001 week 50 IN - Reprint available from: Kong JL Fudan Univ, Dept Chem Shanghai 200433 Peoples R China Fudan Univ, Dept Chem Shanghai 200433 Peoples R China Chinese Acad Sci, Shanghai Inst Plant Physiol Shanghai 200032 Peoples R China <47> UI - 492DX-0016 DD - ISI Document Solution: 492DX AU - Schiff MA AU - Patterson RE AU - Baumgartner RN AU - Masuk M AU - van Asselt-King L AU - Wheeler CM AU - Becker TM MA - rpatters@fhcrc.org RA - Patterson RE TI - Serum carotenoids and risk of cervical intraepithelial neoplasia in Southwestern American Indian women SO - Cancer Epidemiology, Biomarkers & Prevention. 10(11):1219-1222, 2001 Nov. AS - Cancer Epidemiol. Biomarkers Prev 2001 Nov;10(11):1219-1222 PU - AMER ASSOC CANCER RESEARCH, PO BOX 11806, BIRMINGHAM, AL 35202 USA. URL: http://www.aacr.org IS - 1055-9965 MH - Beta-carotene MH - Cancer prevention MH - Alpha-tocopherol MH - Plasma MH - Retinol MH - Fruit MH - Micronutrients MH - Vegetables MH - Dysplasia MH - Dietary. AB - The objective of this research was to evaluate the association between serum carotenoids and cervical intraepithelial neoplasia (CIN) among Southwestern American Indian women. Cases were American Indian women with biopsy-proven CIN II/III cervical lesions (n = 81) diagnosed between November 1994 and October 1997. Controls were American Indian women from the same clinics with normal cervical epithelium (n = 160). All of the subjects underwent interviews and laboratory evaluations. Interviews evaluated demographic information, sexual history, and cigarette smoking. Serum concentrations of alpha -carotene, beta -carotene, beta -cryptoxanthin, lycopene, and lutein/zeaxanthin were measured by high performance liquid chromatography. Cervical human papillomavirus infection was detected using a PCR-based test. Increasing levels of alpha -carotene, beta -cryptoxanthin, and lutein/zeaxanthin were associated with decreasing risk of CIN II/III. In addition, the highest tertiles of beta -cryptoxanthin (odds ratio = 0.39, 95% confidence interval = 0.17-0.91) and lutein/zeaxanthin (odds ratio = 0.40, 95% confidence interval = 0.17-0.95) were associated with the lowest risk of CIN. In conclusion, specially targeted intervention efforts to increase consumption of fruits and vegetables may protect Southwestern American Indian women from developing CIN. [References: 23] LG - English PT - Article SB - Current Contents(R)/Clinical Medicine Current Contents(R)/Life Sciences CC - Oncology in Current Contents(R)/Clinical Medicine. Oncogenesis & Cancer Research in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Patterson RE Fred Hutchinson Canc Res Ctr, Canc Prevent Res Program 1100 Fairview Ave N MP-1002 Seattle, WA 98109 USA Fred Hutchinson Canc Res Ctr, Canc Prevent Res Program Seattle, WA 98109 USA Univ Washington, Dept Epidemiol Seattle, WA 98115 USA Univ New Mexico, Sch Med, Dept Internal Med Albuquerque, NM 87131 USA First Choice Community Hlth Clin Los Lunas, NM 87031 USA Rehoboth Med Ctr Gallup, NM 87301 USA Univ New Mexico, Hlth Sci Ctr, Dept Mol Genet & Microbiol Albuquerque, NM 87131 USA Oregon Hlth Sci Univ, Dept Publ Hlth & Prevent Med Portland, OR 97201 USA <48> UI - 492CT-0022 DD - ISI Document Solution: 492CT AU - Reboredo F RA - Reboredo F TI - Cadmium uptake by Halimioune portulacoides: An ecophysiological study SO - Bulletin of Environmental Contamination & Toxicology. 67(6):926-933, 2001 Dec. AS - Bull. Environ. Contam. Toxicol 2001 Dec;67(6):926-933 PU - SPRINGER-VERLAG, 175 FIFTH AVE, NEW YORK, NY 10010 USA. URL: http://www.springer-ny.com IS - 0007-4861 MH - Chlorophyll fluorescence MH - Tomato plants MH - Localization MH - Accumulation. LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Environment/Ecology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Pharmacology & Toxicology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Reboredo F Univ Nova Lisboa, Fac Ciencias & Tecnol, Microbiol Resource Ctr, CREM P-2825114 Monte De Caparica Portugal Univ Nova Lisboa, Fac Ciencias & Tecnol, Microbiol Resource Ctr, CREM P-2825114 Monte De Caparica Portugal <49> UI - 492LH-0051 DD - ISI Document Solution: 492LH AU - Giardi MT AU - Koblizek M AU - Masojidek J MA - mariateresa.giardi@mlib.cnr.it RA - Giardi MT TI - Photosystem II-based biosensors for the detection of pollutants SO - Biosensors & Bioelectronics. 16(9-12 Special Issue SI):1027-1033, 2001 Dec. AS - Biosens. Bioelectron 2001 Dec;16(9-12 Special Issue SI):1027-1033 PU - ELSEVIER ADVANCED TECHNOLOGY, OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND. URL: http://www.elsevier.nl IS - 0956-5663 MH - Photosystem ii MH - Photosynthetic herbicides MH - Biosensors MH - Heavy metals MH - Clark and printed electrodes. MH - Chlorophyll-a fluorescence MH - Electron-transport MH - Reaction centers MH - Selenastrum-capricornutum MH - Photosynthetic membranes MH - Herbicide inhibition MH - Triazine herbicides MH - Phaseolus-vulgaris MH - Protein-turnover MH - Cadmium. AB - Photosystem II (PSII) is the supramolecular pigment-protein complex in the chloroplast, which catalyses the light-induced transfer of electrons from water to plastoquinone (PQ) in a process that evolves oxygen. The PSII complex is also known to bind some groups of (photosynthetic) herbicides, heavy metals and other chemical substances that affect its activity. The objective of this study is to provide an overview of the systems available for the bioassay of pollutants using biosensors that are based on the photochemical activity of PSII Some applications of the PSII-based biosensors including herbicide, heavy metal monitoring and the detection of radiation in space experiments are reported. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 73] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Biotechnology & Applied Microbiology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Giardi MT Inst Plant Biochem & Ecophysiol, CNR Via Salaria Km 29-3 I-00016 Rome Italy Inst Plant Biochem & Ecophysiol, CNR I-00016 Rome Italy Inst Microbiol, Photosynth Res Ctr Trebon 37981 Czech Republic Inst Landscape Ecol, Photosynth Res Ctr Nove Hrady 37333 Czech Republic Univ S Bohemia, Photosynth Res Ctr Ceske Budejovice 37005 Czech Republic <50> UI - 492WN-0007 DD - ISI Document Solution: 492WN AU - Skulachev VP MA - skulach@genebee.mus.su RA - Skulachev VP TI - Barbara Cannon's data on the UCP1-ablated mice: "Non-cannonical" point of view [Review] SO - Bioscience Reports. 21(2):189-194, 2001 Apr. AS - Biosci. Rep 2001 Apr;21(2):189-194 PU - KLUWER ACADEMIC/PLENUM PUBL, 233 SPRING ST, NEW YORK, NY 10013 USA. URL: http://www.wkap.nl IS - 0144-8463 MH - Uncoupling proteins MH - Thermoregulation MH - Fatty acids MH - Mitochondria MH - Skeletal muscle MH - Brown fat. MH - Uncoupling protein-3 MH - Skeletal-muscle MH - Fatty-acids MH - Mitochondria MH - Ucp1 MH - Bioenergetics MH - Brown. AB - The data of Cannon and co-workers on UCP1-ablated mice are interpreted assuming that UCP2 and UCP3 are involved in thermoregulation as fatty acid-dependent uncouplers although they are not sufficient, in the absence of UCP1, for long term maintenance of normal body temperature of mice after sudden and strong decrease in the ambient temperature. I would like to suggest that in brown fat of control mice, UCP1 is present in an amount higher than UCP2 and 3 and, therefore, is able to cause (a) some fatty acid-mediated decrease in proton motive force in resting state and, hence, (b) oxidation of CoQH(2) to CoQ which is shown by Klingenberg and coworkers to be cofactor for UCPs. This results in strong uncoupling and thermogenesis mediated by UCP1, 2 and 3. In the UCP1-ablated mice, activity of UCP2 and 3 appears to be insufficient to induce CoQH(2) oxidation in resting brown fat mitochondria, which results in hypothermia. [References: 24] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Cell & Developmental Biology in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Skulachev VP Moscow MV Lomonosov State Univ, AN Berlozersky Inst Physicochem Biol, Dept Bioenerget Moscow 119899 Russia Moscow MV Lomonosov State Univ, AN Berlozersky Inst Physicochem Biol, Dept Bioenerget Moscow 119899 Russia <51> UI - 491DB-0016 DD - ISI Document Solution: 491DB AU - Velasco L AU - Mesa S AU - Delgado MJ AU - Bedmar EJ MA - ejbedmar@eez.csic.es RA - Bedmar EJ TI - Characterization of the nirK gene encoding the respiratory, Cu-containing nitrite reductase of Bradyrhizobium japonicum SO - Biochimica et Biophysica Acta - Gene Structure & Expression. 1521(1-3):130-134, 2001 Oct 31. AS - Biochim. Biophys. Acta-Gene Struct. Expression 2001 Oct 31;1521(1-3):130-134 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0167-4781 MH - Denitrification MH - Microaerobiosis MH - Nitrite reduction MH - Respiratory nitrite reductase MH - Amino acid sequence MH - Bradyrhizobium japonicum. MH - Gram-negative bacteria MH - Paracoccus-denitrificans MH - Cloning MH - Expression MH - Oxide MH - Rhodobacter-sphaeroides-2.4.3 MH - Metabolism MH - Pathway. AB - The structural gene. nirK. for the respiratory Cu-containing nitrite reductase from Bradyrhizobium japonicum USDA110 has been isolated and sequenced. The deduced amino acid sequence exhibited a high degree of similarity to other Cu-containing nitrite reductases from various sources. The full-length protein included a signal peptide for protein export. Analysis of the sequence upstream from the structural nirK gene revealed the presence of an anaerobox located 83 base pairs from the putative translational start codon. Cells of strain GRK308, a nitrite reductase-deficient derivative of strain USDA110, were unable to grow when cultured under microaerobic conditions (1% O-2) in the presence of either nitrate or nitrite. Maximal expression of a nirK-lacZ fusion in strain USDA110 required simultaneously both low level oxygen conditions and the presence of nitrate. Expression of beta -galactosidase activity was not detected in the B. japonicum fixL 7403, fixJ 7360 and fixK(2) 9043 mutants transformed with the nirK-lacZ fusion after incubation of the cells under oxy en-limiting conditions either with or without nitrate. Complementation of B. japonicum 9043 with the fixK(2) gene restored beta -galactosidase activity to levels similar to those found in the parental strain. These results suggest that nirK expression depends on the low-oxygen-responsive two-component regulatory system FixLJ and on the Fnr/FixK-like DNA binding protein FixK(2). (C) 2001 Elsevier Science B.V. All rights reserved. [References: 33] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Molecular Biology & Genetics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Bedmar EJ CSIC, Estac Expt Zaidin, Dept Microbiol Suelo & Sistemas Simbiot POB 419 E-18080 Granada Spain CSIC, Estac Expt Zaidin, Dept Microbiol Suelo & Sistemas Simbiot E-18080 Granada Spain <52> UI - 491CZ-0003 DD - ISI Document Solution: 491CZ AU - Fromme P AU - Jordan P AU - Krauss N MA - fromme@phosis1.chem.tu-berlin.de, norbert.krauss@charite.de RA - Fromme P TI - Structure of photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):5-31, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):5-31 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - X-ray crystallography MH - Photosystem i MH - Structure MH - Electron transfer chain MH - Core antenna MH - Membrane protein. MH - Cyanobacterium synechocystis sp MH - Photosynthetic reaction-center MH - Reaction-center complexes MH - Chemical cross-linking MH - Electron-paramagnetic-resonance MH - Flash absorption-spectroscopy MH - Site-directed mutagenesis MH - Primary charge separation MH - Synechococcus sp pcc-7002 MH - Light-harvesting complex. LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Fromme P Tech Univ Berlin, Inst Chem, Max Volmer Lab Biophys Chem Str 17 Juni 135 D-10623 Berlin Germany Tech Univ Berlin, Inst Chem, Max Volmer Lab Biophys Chem D-10623 Berlin Germany Free Univ Berlin, Inst Chem Kristallog D-14195 Berlin Germany Arizona State Univ, Dept Chem & Biochem Tempe, AZ 85287 USA <53> UI - 491CZ-0004 DD - ISI Document Solution: 491CZ AU - Xu W AU - Tang HD AU - Wang YC AU - Chitnis PR MA - chitnis@iastate.edu RA - Chitnis PR TI - Proteins of the cyanobacterial photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):32-40, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):32-40 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Cyanobacteria MH - Mutant MH - Posttranslational modification MH - Structure-function study. MH - Synechocystis sp pcc-6803 MH - Sp strain pcc-7002 MH - Reaction-center subunits MH - Chemical cross-linking MH - Chlamydomonas-reinhardtii MH - Synechococcus-elongatus MH - Targeted inactivation MH - Mass-spectrometry MH - Electron-transfer MH - Mutational analysis. AB - Cyanobacterial photosystem (PS) I is remarkably similar to its counterpart in the chloroplast of plants and algae. Therefore, it has served as a prototype for the type I reaction centers of photosynthesis. Cyanobacterial PS I contains 11-12 proteins. Some of the cyanobacterial proteins are modified post-translationally. Reverse genetics has been used to generate subunit-deficient cyanobacterial mutants, phenotypes of which have revealed the functions of the missing proteins. The cyanobacterial PS I proteins bind cofactors, provide docking sites for electron transfer proteins, participate in tertiary and quaternary organization of the complex and protect the electron transfer centers. Many of these mutants are now being used in sophisticated structure-function analyses. Yet, the roles of some proteins of the cyanobacterial PS I are unknown. It is necessary to examine functions of these proteins on a global scale of cell physiology, biogenesis and evolution. (C) 2001 Published by Elsevier Science B.V. [References: 67] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Chitnis PR Iowa State Univ Sci & Technol, Dept Biochem Biophys & Mol Biol 4156 Mol Biol Bldg Ames, IA 50011 USA Iowa State Univ Sci & Technol, Dept Biochem Biophys & Mol Biol Ames, IA 50011 USA <54> UI - 491CZ-0005 DD - ISI Document Solution: 491CZ AU - Scheller HV AU - Jensen PE AU - Haldrup A AU - Lunde C AU - Knoetzel J MA - hvs@kvl.dk RA - Scheller HV TI - Role of subunits in eukaryotic Photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):41-60, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):41-60 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosynthesis MH - Photosystem i MH - Light harvesting complex MH - Plant MH - Topology MH - Electron transport. MH - Light-harvesting complex MH - Signal recognition particle MH - Site-directed mutagenesis MH - Barley hordeum-vulgare MH - Synechocystis sp pcc-6803 MH - Thylakoid protein-phosphorylation MH - Ferredoxin-nadp+ oxidoreductase MH - Wavelength chlorophyll forms MH - Immediate electron-donor MH - Energy-transfer dynamics. AB - Photosystem I (PSI) of eukaryotes has a number of features that distinguishes it from PSI of cyanobacteria. In plants, the PSI core has three subunits that are not found in cyanobacterial PSI. The remaining I I subunits of the core are conserved but several of the subunits have a different role in eukaryotic PSI. A distinguishing feature of eukaryotic PSI is the membrane-imbedded peripheral antenna. Light-harvesting complex I is composed of four different subunits and is specific for PSI. Light-harvesting complex II can be associated with both PSI and PSII Several of the core subunits interact with the peripheral antenna proteins and are important for proper function of the peripheral antenna. The review describes the role of the different subunits in eukaryotic PSI. The emphasis is on features that are different from cyanobacterial PSI. (C) 2001 Elsevier Science BN. All rights reserved. [References: 151] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Scheller HV Royal Vet & Agr Univ, Dept Plant Biol, Plant Biochem Lab 40 Thorvaldsensvej DK-1871 Copenhagen Denmark Royal Vet & Agr Univ, Dept Plant Biol, Plant Biochem Lab DK-1871 Copenhagen Denmark <55> UI - 491CZ-0006 DD - ISI Document Solution: 491CZ AU - Webber AN AU - Lubitz W MA - andrew.webber@asu.edu RA - Webber AN TI - P700: the primary electron donor of photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):61-79, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):61-79 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem i MH - P700 MH - Electron nuclear double resonance. MH - Photosynthetic reaction-center MH - Rhodobacter-sphaeroides r-26 MH - Chlorophyll cation radicals MH - Time-resolved fluorescence MH - Site-directed mutagenesis MH - High-field epr MH - Magnetic-resonance MH - Triple-resonance MH - Single-crystals MH - G-tensor. AB - The primary electron donor of photosystem I, P700, is a chlorophyll species that in its excited state has a potential of approximately -1.2 V. The precise chemical composition and electronic structure of P700 is still unknown. Recent evidence indicates that P700 is a dimer of one chlorophyll (Chl) a and one Chl a'. The Chl a' and Chl a are axially coordinated by His residues provided by protein subunits PsaA and PsaB, respectively. The Chl a', but not the Chl a, is also H-bonded to the protein. The H-bonding is likely responsible for selective insertion of Chl a' into the reaction center. EPR studies of P700(+.) in frozen solution and single crystals indicate a large asymmetry in the electron spin and charge distribution towards one Chl of the dimer. Molecular orbital calculations indicate that H-bonding will specifically stabilize the Chl a'-side of the dimer, suggesting that the unpaired electron would predominantly reside on the Chl a. This is supported by results of specific mutagenesis of the PsaA and PsaB axial His residues, which show that only mutations of the PsaB subunit significantly alter the hyperfine coupling constants associated with a single Chl molecule. The PsaB mutants also alter the microwave induced triplet-minus-singlet spectrum indicating that the triplet state is localized on the same Chl. Excitonic coupling between the two Chl a of P700 is weak due to the distance and overlap of the porphyrin planes. Evidence of excitonic. coupling is found in PsaB mutants which show a new bleaching band at 665 nin that likely represents an increased intensity of the upper exciton band of P700. Additional properties of P700 that may give rise to its unusually low potential are discussed. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 96] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Webber AN Arizona State Univ, Dept Plant Biol POB 871601 Tempe, AZ 85287 USA Arizona State Univ, Dept Plant Biol Tempe, AZ 85287 USA Arizona State Univ, Ctr Study Early Events Photosynth Tempe, AZ 85287 USA Tech Univ Berlin, Max Volmer Lab Biophys Chem D-10623 Berlin Germany <56> UI - 491CZ-0007 DD - ISI Document Solution: 491CZ AU - Gobets B AU - van Grondelle R MA - rienk@nat.vu.nl RA - van Grondelle R TI - Energy transfer and trapping in photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):80-99, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):80-99 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem i MH - Excitation energy transfer MH - Trapping MH - Time-resolved fluorescence MH - Target analysis. MH - Light-harvesting complex MH - Synechocystis sp pcc-6803 MH - Cyanobacterium spirulina-platensis MH - Photosynthetic reaction-center MH - Time-resolved fluorescence MH - Wavelength antenna chlorophylls MH - Primary charge separation MH - Excited-state dynamics MH - Core antenna MH - Synechococcus-elongatus. LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: van Grondelle R Free Univ Amsterdam, Fac Exact Sci, Div Phys & Astron De Boelelaan 1081 NL-1081 HV Amsterdam Netherlands Free Univ Amsterdam, Fac Exact Sci, Div Phys & Astron NL-1081 HV Amsterdam Netherlands Free Univ Amsterdam, Inst Mol Biol Sci NL-1081 HV Amsterdam Netherlands <57> UI - 491CZ-0008 DD - ISI Document Solution: 491CZ AU - Brettel K AU - Leibl W MA - brettel@dsvidf.cea.fr RA - Brettel K TI - Electron transfer in photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):100-114, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):100-114 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem i MH - Electron transfer MH - Phylloquinone MH - Iron-sulfur cluster. MH - Iron-sulfur centers MH - Photosynthetic reaction-center MH - Flash absorption-spectroscopy MH - Biosynthetic-pathway mutants MH - Synechocystis sp pcc-6803 MH - Clusters f-a MH - Rhodopseudomonas-viridis MH - Soluble ferredoxin MH - Foreign quinone MH - Acceptor a(1). AB - This mini-review focuses on recent experimental results and questions, which came up since the last more comprehensive reviews on the subject. We include a brief discussion of the different techniques used for time-resolved studies of electron transfer in photosystem I (PS I) and relate the kinetic results to new structural data of the PS I reaction centre. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 71] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Brettel K CEA Saclay, Dept Biol Cellulaire & Mol, Sect Bioenerget F-91191 Gif Sur Yvette France CEA Saclay, Dept Biol Cellulaire & Mol, Sect Bioenerget F-91191 Gif Sur Yvette France CEA Saclay, Dept Biol Cellulaire & Mol, CNRS, URA 2096 F-91191 Gif Sur Yvette France <58> UI - 491CZ-0009 DD - ISI Document Solution: 491CZ AU - Itoh S AU - Iwaki M AU - Ikegami I MA - itoh@bio.pphys.nagoya-u.ac.jp RA - Itoh S TI - Modification of photosystem I reaction center by the extraction and exchange of chlorophylls and quinones [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):115-138, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):115-138 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Electron transfer MH - Chlorophyll MH - Quinone MH - P700 MH - Photosystem i MH - Reaction center. MH - Biosynthetic-pathway mutants MH - Reaction-center complex MH - Resolved fluorescence spectroscopy MH - Oxygenic photosynthetic prokaryote MH - Bacterium heliobacterium-chlorum MH - Wavelength antenna chlorophylls MH - Electron-paramagnetic-resonance MH - Spinach-chloroplasts MH - P-700-enriched particles MH - Low-temperature. AB - The photosystem. (PS) I photosynthetic reaction center was modified thorough the selective extraction and exchange of chlorophylls and quinones. Extraction of lyophilized photosystem I complex with diethyl ether depleted more than 90% chlorophyll (Chl) molecules bound to the complex, preserving the photochemical electron transfer activity from the primary electron donor P700 to the acceptor chlorophyll A(0). The treatment extracted all the carotenoids and the secondary acceptor phylloquinone (A(1)), and produced a PS I reaction center that contains nine molecules of Chls including P700 and A(0), and three Fe-S clusters (F-X, F-A and F-B). The ether-extracted PS I complex showed fast electron transfer from P700 to A(0) as it is, and to FeS clusters if phylloquinone or an appropriate artificial quinone was reconstituted as A(1) The ether-extracted PS I enabled accurate detection of the primary photoreactions with little disturbance from the absorbance changes of the bulk pigments. The quinone reconstitution created the new reactions between the artificial cofactors and the intrinsic components with altered energy gaps. We review the studies done in the ether-extracted PS I complex including chlorophyll forms of the core moiety of PS I, fluorescence of P700, reaction rate between A(0) and reconstituted A(1) and the fast electron transfer from P700 to A(0). Natural exchange of chlorophyll a to 710-740 mn absorbing chlorophyll d in PS I of the newly found cyanobacteria-like organism Acaryochloris marina was also reviewed. Based on the results of exchange studies in different systems, designs of photosynthetic reaction centers are discussed. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 105] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Itoh S Nagoya Univ, Grad Sch Sci, Div Mat Sci Phys, Lab Photobioenerget,Chikusa Ku Nagoya Aichi 4460826 Japan Nagoya Univ, Grad Sch Sci, Div Mat Sci Phys, Lab Photobioenerget,Chikusa Ku Nagoya Aichi 4460826 Japan CEA Saclay F-91191 Gif Sur Yvette France Teikyo Univ, Fac Pharmaceut Sci, Chem Lab Sagamiko Kanagawa 1990195 Japan <59> UI - 491CZ-0010 DD - ISI Document Solution: 491CZ AU - Vassiliev IR AU - Antonkine ML AU - Golbeck JH MA - jh5@psu.edu RA - Golbeck JH TI - Iron-sulfur clusters in type I reaction centers [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):139-160, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):139-160 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem 1 MH - Electron paramagnetic resonance (epr) MH - Nuclear magnetic resonance (nmr) MH - Electron transfer MH - Charge recombination MH - Kinetics MH - Equilibrium MH - Iron-sulfur cluster MH - F-a MH - F-b MH - F-x MH - Psac. MH - Photosynthetic reaction-center MH - Primary electron-acceptor MH - Reaction-center complex MH - Synechocystis sp pcc-6803 MH - Reaction-center core MH - Peptococcus-aerogenes ferredoxin MH - Bacterium chlorobium-vibrioforme MH - Cyanobacterium synechococcus sp MH - Site-directed mutagenesis MH - Spinach photosystem-i. AB - Type I reaction centers (RCs) are multisubunit chlorophyll-protein complexes that function in photosynthetic organisms to convert photons to Gibbs free energy. The unique feature of Type I RCs is the presence of iron-sulfur clusters as electron transfer cofactors. Photosystem I (PS I) of oxygenic phototrophs is the best-studied Type I RC. It is comprised of an interpolypeptide [4Fe-4S] cluster, F-X, that bridges the PsaA and PsaB subunits, and two terminal [4Fe-4S] clusters, F-A and F-B, that are bound to the PsaC subunit. In this review, we provide an update on the structure and function of the bound iron-sulfur clusters in Type I RCs. The first new development in this area is the identification of F-A as the cluster proximal to F-X and the resolution of the electron transfer sequence as F-X --> F-A --> F-B --> soluble ferredoxin. The second new development is the determination of the three-dimensional NNM solution structure of unbound PsaC and localization of the equal- and mixed-valence pairs in F-A(-) and F-B(-). We provide a survey of the EPR properties and spectra of the iron-sulfur clusters in Type I RCs of cyanobacteria, green sulfur bacteria, and heliobacteria, and we summarize new information about the kinetics of back-reactions involving the iron-sulfur clusters. (C) 2001 Published by Elsevier Science B.V. [References: 125] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Golbeck JH Penn State Univ, Dept Biochem & Mol Biol 310 S Frear Bldg University Pk, PA 16802 USA Penn State Univ, Dept Biochem & Mol Biol University Pk, PA 16802 USA <60> UI - 491CZ-0012 DD - ISI Document Solution: 491CZ AU - Breton J MA - cadara3@dsvidf.cea.fr RA - Breton J TI - Fourier transform infrared spectroscopy of primary electron donors in type I photosynthetic reaction centers [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):180-193, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):180-193 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosynthesis MH - Photosystem i MH - Type i reaction center MH - Primary electron donor MH - Fourier transform infrared spectroscopy. MH - Resonance-raman-spectroscopy MH - Bacterial reaction centers MH - Ftir difference spectroscopy MH - Photosystem-i MH - Chlorophyll-a MH - Triplet-state MH - Heliobacillus-mobilis MH - Spinach-chloroplasts MH - Magnetic-resonance MH - Axial ligands. AB - The vibrational properties of the primary electron donors (P) of type I photosynthetic reaction centers, as investigated by Fourier transform infrared (FTIR) difference spectroscopy in the last 15 years, are briefly reviewed. The results obtained on the microenvironment of the chlorophyll molecules in P700 of photosystem. I and of the bacteriochlorophyll molecules in P840 of the green bacteria (Chlorobium) and in P798 of heliobacteria are presented and discussed with special attention to the bonding interactions with the protein of the carbonyl groups and of the central Mg atom of the pigments. The observation of broad electronic transitions in the mid-IR for the cationic state of all the primary donors investigated provides evidence for charge repartition over two (B)Chl molecules. In the green sulfur bacteria and the heliobacteria, the assignments proposed for the carbonyl groups of P and P+ are still very tentative. In contrast, the axial ligands of P700 in photosystem I have been identified and the vibrational properties of the chlorophyll (Chl) molecules involved in P700, P700(+), and (3)P700 are wen described in terms of two molecules, denoted P-1 and P-2, with very different hydrogen bonding patterns. While P, has hydrogen bonds to both the 9-keto and the 10a-ester C = O groups and bears all the triplet character in (3)P700, the carbonyl groups Of P-2 are free from hydrogen bonding. The positive charge in P700(+) is shared between the two Chl molecules with a ratio ranging from 1:1 to 2:1, in favor of P-2, depending on the temperature and the species. The localization of the triplet in (3)P700 and of the unpaired electron in P700(+) deduced from FTIR spectroscopy is in sharp contrast with that resulting from the analysis of the magnetic resonance experiments. However, the FTIR results are in excellent agreement with the most recent structural model derived from X-ray crystallography of photosystem I at 2.5 Angstrom resolution that reveals the hydrogen bonds to the carbonyl groups of the Chl in P700 as well as the histidine ligands of the central Mg atoms predicted from the FTIR data. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 60] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Breton J CEA Saclay, DBCM, SBE F-91191 Gif Sur Yvette France CEA Saclay, DBCM, SBE F-91191 Gif Sur Yvette France <61> UI - 491CZ-0013 DD - ISI Document Solution: 491CZ AU - Bittl R AU - Zech SG MA - robert.bittl@tu-berlin.de RA - Bittl R TI - Pulsed EPR spectroscopy on short-lived intermediates in photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):194-211, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):194-211 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Pulsed epr spectroscopy MH - Short-lived intermediates MH - Angular dependence MH - Radical pair p(700)(center dot+)a(1)(center dot-). MH - Electron-spin echo MH - Correlated radical pairs MH - Photosynthetic reaction centers MH - Bacterial reaction centers MH - Paramagnetic-resonance spectroscopy MH - Multiple-quantum echoes MH - Time-resolved epr MH - W-band epr MH - Transient epr MH - State p(700)(center-dot+)a(1)(center-dot-). AB - The application of pulsed electron paramagnetic resonance spectroscopy on short-lived intermediates in Photosystem I is reviewed. The spin polarization in light-induced radical pairs gives rise to a phase shifted 'out-of-phase' electron spin echo signal. This echo signal shows a prominent modulation of its intensity as a function of the spacing between the two microwave pulses. Its modulation frequency is determined by the electron-electron spin couplings within the radical pair. Thereby, the measurement of the dipolar coupling gives direct information about the spin-spin distance and can therefore be used to determine cofactor distances with high precision. Application of this technique to the radical pair F-700(.+) A(1)(.-) in Photosystem I is discussed. Moreover, if oriented samples (e.g. single crystals) are used, the angular dependence of the dipolar coupling can be used to derive the orientation of the axis connecting donor and acceptor with respect to an external (crystal) axes system. Using out-of-phase electron spin echo envelope modulation spectroscopy, the localization of the secondary acceptor quinone A(1) has become possible. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 73] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Bittl R Tech Univ Berlin, Max Volmer Inst Str 17 Juni 135 D-10623 Berlin Germany Tech Univ Berlin, Max Volmer Inst D-10623 Berlin Germany Free Univ Berlin, Fachbereich Phys D-14195 Berlin Germany <62> UI - 491CZ-0014 DD - ISI Document Solution: 491CZ AU - van der Est A MA - avde@spartan.ac.brocku.ca RA - van der Est A TI - Light-induced spin polarization in type I photosynthetic reaction centres [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):212-225, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):212-225 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Electron spin resonance MH - Electron transfer MH - Quinone MH - Radical pair MH - Iron-sulphur center. MH - Bacterial reaction centers MH - Correlated radical pairs MH - Electron-paramagnetic-resonance MH - Transient epr spectroscopy MH - Biosynthetic-pathway mutants MH - Iron-sulfur centers MH - W-band epr MH - Rhodobacter-sphaeroides r-26 MH - Time-resolved epr MH - Photosystem-i. AB - The use of light-induced spin polarization to study the structure and function of type I reaction centres is reviewed. The absorption of light by these systems generates a series of sequential radical pairs, which exhibit spin polarization as a result of the correlation of the unpaired electron spins. A description of how the polarization patterns can be used to deduce the relative orientation of the radicals is given and the most important structural results from such studies on photosystem I (PS I) are summarized. Quinone exchange experiments which demonstrate the influence of protein-cofactor interactions on the polarization patterns are discussed. The results show that there are significant differences between the binding sites of the primary quinone acceptors in PS I and purple bacterial reaction centres and suggest that pi-pi interactions probably play a more important role in PS I. Studies using spin-polarized EPR transients and spectra to investigate the electron transfer pathway and kinetics are also reviewed. The results from PS I, green-sulphur bacteria and Heliobacteria are compared and the controversy surrounding the role of a quinone in the electron transfer in the latter two systems is discussed. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 88] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: van der Est A Brock Univ, Dept Chem 500 Glenridge Ave St Catharines ON L2S 3A1 Canada Brock Univ, Dept Chem St Catharines ON L2S 3A1 Canada <63> UI - 491CZ-0015 DD - ISI Document Solution: 491CZ AU - Deligiannakis Y AU - Rutherford AW MA - ideligia@cc.uoi.gr RA - Deligiannakis Y TI - Electron spin echo envelope modulation spectroscopy in photosystem I [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):226-246, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):226-246 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Electron spin echo envelope modulation MH - Hyperfine sublevel correlation spectroscopy MH - Photosystem i MH - N-14 MH - N-15 MH - A(1) MH - P-700. MH - Photosynthetic reaction-center MH - N-15-labeled radical cations MH - Primary donor p-700 MH - Chlorophyll-a MH - Rhodobacter-sphaeroides MH - Oxidized chlorophyll MH - Disordered-systems MH - Axial ligands MH - P700 centers MH - Resonance. AB - The applications of electron spin echo envelope modulation (ESEEM) spectroscopy to study paramagnetic centers in photosystem. I (PSI) are reviewed with special attention to the novel spectroscopic techniques applied and the structural information obtained. We briefly summarize the physical principles and experimental techniques of ESEEM, the spectral shapes and the methods for their analysis. In PSI, ESEEM spectroscopy has been used to the study of the cation radical form of the primary electron donor chlorophyll species, P-700(+) and the phyllosemiquinone anion radical, A(1)(-), that acts as a low I potential electron carrier. For P-700(+) ESEEM has contributed to a debate concerning whether the cation is localized on a one or two chlorophyll molecules. This debate is treated in detail and relevant data from other methods, particularly electron nuclear double resonance (ENDOR), are also discussed. It is concluded that the ESEEM and ENDOR data can be explained in terms of five distinct nitrogen couplings, four from the tetrapyrrole ring and a fifth from an axial ligand. Thus the ENDOR and ESEEM data can be fully accounted for based on the spin density being localized on a single chlorophyll molecule. This does not eliminate the possibility that some of the unpaired spin is shared with the other chlorophyll of P-700(+); so far, however, no unambiguous evidence has been obtained from these electron paramagnetic resonance methods, The ESEEM of the phyllosemiquinone radical A(1)(-) provided the first evidence for a tryptophan molecule pi -stacked over the semiquinone and for a weaker interaction from an additional nitrogen nucleus. Recent site-directed mutagenesis studies verified the presence of the tryptophan close to A(1), while the recent crystal structure showed that the tryptophan was indeed pi -stacked and that a weak potential H-bond from an amide backbone to one of the (semi)quinone carbonyls is probably the origin of the to the second nitrogen coupling seen in the ESEEM. ESEEM has already played an important role in the structural charaterization on PSI and since it specifically probes the radical forms of the chromophores and their protein environment, the information obtained is complimentary to the crystallography. ESEEM then will continue to provide structural information that is often unavailable using other methods. (C) 2001 Published by Elsevier Science B.V. [References: 78] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Deligiannakis Y Univ Ioannina, Dept Environm & Nat Resources, Chem Phys Lab Pyllinis 9 Agrinion 30100 Greece Univ Ioannina, Dept Environm & Nat Resources, Chem Phys Lab Agrinion 30100 Greece CEA Saclay, Dept Biol Cellulaire & Mol, CNRS, URA 2096,Sect Bioenerget F-91191 Gif Sur Yvette France <64> UI - 491CZ-0016 DD - ISI Document Solution: 491CZ AU - Rigby SEJ AU - Evans MCW AU - Heathcote P MA - s.e.rigby@qmw.ac.uk RA - Rigby SEJ TI - Electron nuclear double resonance (ENDOR) spectroscopy of radicals in photosystem I and related Type 1 photosynthetic reaction centres [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):247-259, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):247-259 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem i MH - Green sulfur bacterium MH - Heliobacterium MH - A(1) MH - A(0) MH - P-700 MH - P-840 MH - P-798. MH - Special triple-resonance MH - Chlorophyll cation radicals MH - Bacterial reaction centers MH - Green sulfur bacteria MH - Primary donor MH - Excited-states MH - Binding-site MH - Rhodobacter-sphaeroides MH - 4-angstrom resolution MH - Heliobacillus-mobilis. LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Rigby SEJ Univ London, Sch Biol Sci Mile End Rd London E1 4NS England Univ London, Sch Biol Sci London E1 4NS England Univ Coll London, Dept Biol London WC1E 6BT England <65> UI - 491CZ-0017 DD - ISI Document Solution: 491CZ AU - Hauska G AU - Schoedl T AU - Remigy H AU - Tsiotis G MA - guenther.hauska@biologie.uni-regensburg.de RA - Hauska G TI - The reaction center of green sulfur bacteria [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):260-277, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):260-277 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Green sulfur bacteria MH - Homodimeric p840 reaction center MH - Fes type reaction center MH - Photosynthetic electron transport MH - Energy transfer MH - Bacteriochlorophyll protein MH - Menaquinone MH - Cytochrome MH - Scanning transmission electron microscopy particle analysis. MH - Photosynthetic reaction-center MH - Reaction-center complex MH - Biosynthetic-pathway mutants MH - Center core complexes MH - Electron-paramagnetic-resonance MH - Chlorobium-tepidum MH - Photosystem-i MH - Prosthecochloris-aestuarii MH - A(1) site MH - Foreign quinone. AB - The composition of the P840-reaction center complex (RC), energy and electron transfer within the RC, as well as its topographical organization and interaction with other components in the membrane of green sulfur bacteria are presented, and compared to the FeS-type reaction centers of Photosystem I and of Heliobacteria. The core of the RC is homodimeric, since pscA is the only gene found in the genome of Chlorobium tepidum which resembles the genes psaA and -B for the heterodimeric core of Photosystem I. Functionally intact RC can be isolated from several species of green sulfur bacteria. It is generally composed of five subunits, PscA-D plus the BChl a-protein FMO. Functional cores, with PscA and PscB; only, can be isolated from Prostecochloris aestuarii. The PscA-dimer binds P840, a special pair of BChl a-molecules, the primary electron acceptor A(0), which is a Chl a-derivative and FeS-center F-X. An equivalent to the electron acceptor A, in Photosystem I, which is tightly bound phylloquinone acting between A(0) and F-X, is not required for forward electron transfer in the RC of green sulfur bacteria. This difference is reflected by different rates of electron transfer between A(0) and F-X in the two systems. The subunit PscB contains the two FeS-centers F-A and F-B. STEM particle analysis suggests that the core of the RC with PscA and PscB resembles the PsaAB/PsaC-core of the P700-reaction center in Photosystem 1. PscB may form a protrusion into the cytoplasmic space where reduction of ferredoxin occurs, with FMO trimers bound on both sides of this protrusion. Thus the subunit composition of the RC in vivo should be 2(FMO)(3)(PscA)(2)PscB(PScC)(2)PscD. Only 16 BChl a-, four Chl a-molecules and two carotenoids are bound to the RC-core, which is substantially less than its counterpart of Photosystem I, with 85 Chl a-molecules and 22 carotenoids. A total of 58 BChl a/RC are present in the membranes of green sulfur bacteria outside the chlorosomes, corresponding to two trimers of FMO (42 Bchl a) per RC (16 BChl a), The question whether the homodimeric RC is totally symmetric is still open. Furthermore, it is still unclear which cytochrome c is the physiological electron donor to P840(+). Also the way of NAD(+)-reduction is unknown, since a gene equivalent to ferredoxin-NADP(+) reductase is not present in the genome. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 116] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Hauska G Univ Regensburg, Fak Biol & Vorklin Med, Lehrstuhl Zellbiol & Pflanzenphysiol D-93040 Regensburg Germany Univ Regensburg, Fak Biol & Vorklin Med, Lehrstuhl Zellbiol & Pflanzenphysiol D-93040 Regensburg Germany Univ Basel, Biozentrum, ME Muller Inst Microscop Struct Biol CH-4056 Basel Switzerland Univ Crete, Dept Chem, Div Biochem Iraklion 71409 Greece <66> UI - 491CZ-0018 DD - ISI Document Solution: 491CZ AU - Neerken S AU - Amesz J MA - sigi@biophys.leidenuniv.nl RA - Neerken S TI - The antenna reaction center complex of heliobacteria: composition, energy conversion and electron transfer [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):278-290, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):278-290 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Heliobacterium MH - Electron transfer MH - Energy transfer MH - Bacteriochlorophyll g. MH - Photosynthetic reaction centers MH - Green-sulfur bacteria MH - Time-resolved spectroscopy MH - Center core complexes MH - C-type cytochromes MH - Heliobacillus-mobilis MH - Photosystem-i MH - Bacteriochlorophyll-g MH - Sp-nov MH - Chlorobium-tepidum. AB - A survey is given of various aspects of the photosynthetic processes in heliobacteria. The review mainly refers to results obtained since 1995, which had not been covered earlier. It first discusses the antenna organization and pigmentation. The pigments of heliobacteria include some unusual species: bacteriochlorophyll (BChl) g, the main pigment, 8(1) hydroxy chlorophyll a, which acts as primary electron acceptor, and 4,4'-diaponeurosporene, a carotenoid with 30 carbon atoms. Energy conversion within the antenna is very fast: at room temperature thermal equilibrium among the approx. 35 BChls g of the antenna is largely completed within a few ps. This is then followed by primary charge separation, involving a dimer of BChl g (P798) as donor, but recent evidence indicates that excitation of the acceptor pigment 8(1) hydroxy chlorophyll a gives rise to an alternative primary reaction not involving excited P798. The final section of the review concerns secondary electron transfer, an area that is relatively poorly known in heliobacteria. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 115] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Neerken S Leiden Univ, Huygens Lab, Dept Biophys POB 9504 NL-2300 RA Leiden Netherlands Leiden Univ, Huygens Lab, Dept Biophys NL-2300 RA Leiden Netherlands <67> UI - 491CZ-0019 DD - ISI Document Solution: 491CZ AU - Baymann D AU - Brugna M AU - Muhlenhoff U AU - Nitschke W MA - nitschke@ibsm.cnrs-mrs.fr RA - Nitschke W TI - Daddy, where did (PS)I come from? [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1507(1-3 Special Issue SI):291-310, 2001 Oct 30. AS - Biochim. Biophys. Acta-Bioenerg 2001 Oct 30;1507(1-3 Special Issue SI):291-310 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem i MH - Rci type reaction centre MH - Bioenergetics MH - Electron transport MH - Evolution. MH - Photosynthetic reaction-center MH - Cyanobacterium synechocystis sp MH - Site-directed mutagenesis MH - Reaction-center complexes MH - Fast-electron transfer MH - Photosystem-i complexes MH - Green sulfur bacterium MH - Cytochrome c(6) MH - Synechococcus sp MH - Early evolution. AB - The reacton centre I (RCI)-type photosystems from plants, cyano-, helio- and green sulphur bacteria are compared and the essential properties of an archetypal RCI are deduced. Species containing RCI-type photosystems most probably cluster together on a common branch of the phylogenetic tree. The predicted branching order is green sulphur, helio- and cyanobacteria. Striking similarities between RCI- and RCII-type photosystems recently became apparent in the three-dimensional structures of photosystem I (PSI), PSII and RCII The phylogenetic relationship between all presently known photosystems is analysed suggesting (a) RCI as the ancestral photosystem and (b) the descendence of PSII from RCI via gene duplication and gene splitting. An evolutionary model trying to rationalise available data is presented. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 88] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Nitschke W Inst Biol Struct & Microbiol, UPR 9036, Lab Bioenerget & Ingenierie Prot 31 Chemin Joseph Aiguier F-13402 Marseille 20 France Inst Biol Struct & Microbiol, UPR 9036, Lab Bioenerget & Ingenierie Prot F-13402 Marseille 20 France Univ Marburg, Inst Zytobiol D-35037 Marburg Germany <68> UI - 490NC-0027 DD - ISI Document Solution: 490NC AU - Hendriks JHM AU - Prior L AU - Baker AR AU - Thomson AJ AU - Saraste M AU - Watmough NJ MA - n.watmough@uea.ac.uk RA - Watmough NJ TI - Reaction of carbon monoxide with the reduced active site of bacterial nitric oxide reductase SO - Biochemistry. 40(44):13361-13369, 2001 Nov 6. AS - Biochemistry 2001 Nov 6;40(44):13361-13369 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.acs.org IS - 0006-2960 MH - Cytochrome-c-oxidase MH - Magnetic circular-dichroism MH - Heme-copper oxidases MH - Ligand-binding properties MH - Escherichia-coli MH - Paracoccus-denitrificans MH - Rhodobacter-sphaeroides MH - Terminal oxidases MH - Flash-photolysis MH - Dinuclear center. AB - Bacterial nitric oxide reductase (NOR), a member of the superfamily of heme-copper oxidases, catalyzes the two-electron reduction of nitric oxide to nitrous oxide. The key feature that distinguishes NOR from the typical heme-copper oxidases is the elemental composition of the dinuclear center, which contains non-heme iron (Fe-B) rather than copper (Cu-B). UV-vis electronic absorption and room-temperature magnetic circular dichroism (RT-MCD) spectroscopies showed that CO binds to Fe(II) heme b(3) to yield a low-spin six-coordinate species. Photolysis of the Fe(II)-CO bond is followed by CO recombination (k(on) = 1.7 x 10(8) M-1 s(-1)) that is approximately 3 orders of magnitude faster than CO recombination to the active site of typical heme-copper oxidases (k(on) = 7 x 10(4) M-1 s(-1)). This rapid rate of CO recombination suggests an unimpeded pathway to the active site that may account for the enzyme's high affinity for substrate, essential for maintaining denitrification at low concentrations of NO. In contrast, the initial binding of CO to reduced heme b3 measured by stopped-flow spectroscopy is much slower (k(on) = 1.2 x 10(5) M-1 s(-1)). This suggests that an existing heme distal ligand (water/OH-) may be displaced to elicit the spin-state change observed in the RT-MCD spectrum. [References: 53] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Watmough NJ Univ E Anglia, Sch Biol Sci, Ctr Metalloprot Spect & Biol Norwich NR4 7TJ Norfolk England Univ E Anglia, Sch Biol Sci, Ctr Metalloprot Spect & Biol Norwich NR4 7TJ Norfolk England Univ E Anglia, Sch Chem Sci Norwich NR4 7TJ Norfolk England European Mol Biol Lab D-69126 Heidelberg Germany <69> UI - 492QC-0009 DD - ISI Document Solution: 492QC AU - Close DC AU - Beadle CL AU - Hovenden MJ MA - dugald.close@ffp.csiro.au RA - Close DC TI - Cold-induced photoinhibition and foliar pigment dynamics of Eucalyptus nitens seedlings during establishment SO - Australian Journal of Plant Physiology. 28(11):1133-1141, 2001. AS - Aust. J. Plant Physiol 2001;28(11):1133-1141 PU - C S I R O PUBLISHING, 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA. URL: http://www.publish.csiro.au IS - 0310-7841 MH - Beta-carotene MH - Chlorophyll MH - Chlorophyll fluorescence MH - Frost MH - Lutein MH - Neoxanthin MH - Nutrient-deprived MH - Photosynthesis MH - Shade MH - Xanthophyll cycle. MH - Dependent energy-dissipation MH - Chilling-enhanced photooxidation MH - Different light environments MH - Xanthophyll cycle activity MH - Photosystem-ii efficiency MH - Carotenoid composition MH - Higher-plants MH - Nitrogen nutrition MH - Seasonal-changes MH - Singlet oxygen. AB - The effects of cold-induced photoinhibition on chlorophyll and carotenoid dynamics and xanthophyll cycling in Eucalyptus nitens (Deane and Maiden) Maiden were assessed between planting and 32 weeks after planting. The seedlings were fertilised or nutrient-deprived (non-fertilised) before planting and shaded or not shaded after planting. The experimental site was 700 m a. s. l., which is considered marginal for establishment of E. nitens plantations in Tasmania due to low mean annual minimum temperatures. Low temperature-high light conditions caused a reduction in variable to maximal chlorophyll fluorescence ratio (F-v/F-m), which was more pronounced in non-fertilised than in fertilised seedlings. Shadecloth shelters alleviated this depression. Except in shaded fertilised seedlings, F-v/F-m did not recover to the level before planting until after 20 weeks. Total chlorophyll content was initially reduced in shaded treatments but subsequently increased with increasing temperatures and F-v/F-m. Total xanthophyll content and xanthophylls per unit chlorophyll remained relatively constant in fertilised seedlings but decreased in non-fertilised seedlings within 2 weeks after planting. Total xanthophyll and xanthophylls per unit chlorophyll subsequently recovered in non-shaded, non-fertilised seedlings with increasing temperatures and F-v/F-m. Diurnal [yield and non-photochemical quenching (NPQ] and seasonal (F-v/F-m) variation in chlorophyll fluorescence parameters were not reflected in xanthophyll cycling during the period of most severe photoinhibition. This result may indicate that chlorophyll-xanthophylls protein complexes form in winter-acclimated E. nitens foliage as have been demonstrated to occur in Eucalyptus pauciflora Sieb. ex Spreng. (Gilmore and Ball 2000, Proceedings of the National Academy of Sciences USA 97, 11098-11101). [References: 63] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Close DC Cooperat Res Ctr Sustainable Prod Forestry GPO Box 252-12 Hobart Tas 7001 Australia Cooperat Res Ctr Sustainable Prod Forestry Hobart Tas 7001 Australia Univ Tasmania, Sch Plant Sci Hobart Tas 7001 Australia Univ Tasmania, Sch Agr Sci Hobart Tas 7001 Australia CSIRO Hobart Tas 7001 Australia <70> UI - 492QC-0011 DD - ISI Document Solution: 492QC AU - Tomek P AU - Lazar D AU - Ilik P AU - Naus J MA - tomekp@prfnw.upol.cz RA - Tomek P TI - On the intermediate steps between the O and P steps in chlorophyll alpha fluorescence rise measured at different intensities of exciting light SO - Australian Journal of Plant Physiology. 28(11):1151-1160, 2001. AS - Aust. J. Plant Physiol 2001;28(11):1151-1160 PU - C S I R O PUBLISHING, 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA. URL: http://www.publish.csiro.au IS - 0310-7841 MH - Chlorophyll alpha fluorescence induction MH - Intensity of exciting light MH - Mathematical simulation MH - O-j-i-p transient MH - Psii heterogeneity MH - Q(a) reduction. MH - Radical-pair equilibrium MH - Strong continuous illumination MH - Restricted energy-transfer MH - Inactive photosystem-ii MH - A fluorescence MH - Numerical-simulation MH - Polyphasic rise MH - Photosynthetic units MH - Spinach-chloroplasts MH - Induction kinetics. AB - It is known that the characteristic O-I-P transient of the fast chlorophyll a fluorescence rise (FR) detected under low intensity of exciting light, changes to the O-J-I-P (O-I-1-I-2-P) transient under higher intensity of exciting light. In this work, we extend an application of the mathematical model of FR [Lazar et al. (1997) Pesticide Biochemistry and Physiology 57, 200-210], involving photosystem II (PSII) heterogeneity and simulating the O-J-I-P transient, for modeling of FR under different intensities of exciting light. Our simulations qualitatively agree well with experimental FR curves obtained with wheat leaves. The simulations demonstrate that the first step after the O fluorescence level (the I step and the J step under lower and higher intensities of exciting light, respectively) is caused mainly by the accumulation of reduced Q(A) electron acceptors without reduction of subsequent electron acceptors. The first step appears at shorter times with increasing intensity of exciting light as reported previously [Strasser et al. (1995) Photochemistry and Photobiology 61, 32-42]. Our simulations also demonstrate, in accordance with previous publications, that the O-I phase in FR detected under low intensity of exciting light, reflects mainly the accumulation of Q(A)(-) in the Q(B)-non-reducing PSII centers and partly also the accumulation of Q(A)(-) in the Q(B)-reducing PSII centers. In our model, the accumulation of Q(A)- in the Q(B)-non-reducing PSII centers gradually shifts with increasing intensity of exciting light to shorter times and participates in the formation of the O-J phase; this is also supported by measurements of FR with wheat leaves treated with 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU). Under high intensity of exciting light, the O-J phase in FR also markedly reflects the accumulation of Q(A)(-) in the Q(B)-reducing PSII centers. Our simulations also support the previously reported suggestion of Strasser's group that the I step in FR obtained under high intensity of exciting light (in the position of the I step detected under lower intensity of exciting light) appears mainly owing to the accumulation of the Q(A)-Q(B)(2-) and Q(A)(-)Q(B)H(2) forms. [References: 52] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Animal & Plant Sciences in Current Contents(R)/Life Sciences. EW - 2001 week 50 IN - Reprint available from: Tomek P Palacky Univ, Fac Sci, Dept Expt Phys Tr Svobody 26 Olomouc 77146 Czech Republic Palacky Univ, Fac Sci, Dept Expt Phys Olomouc 77146 Czech Republic Univ S Bohemia, Photosynth Res Ctr Ceske Budejovice 37005 Czech Republic <71> UI - 493CY-0008 DD - ISI Document Solution: 493CY AU - Inouye CY AU - Hill GE AU - Stradi RD AU - Montgomerie R MA - ghill@acesag.auburn.edu RA - Hill GE TI - Carotenoid pigments in male House Finch plumage in relation to age, subspecies, and ornamental coloration SO - Auk. 118(4):900-915, 2001 Oct. AS - AUK 2001 Oct;118(4):900-915 PU - AMER ORNITHOLOGISTS UNION, ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA. URL: http://www.nmnh.si.edu/BIRDNET/AOU/index.html IS - 0004-8038 MH - Bird plumage MH - Carpodacus-mexicanus MH - Geographic-variation MH - Sexual selection MH - Male quality MH - Absorption MH - Metabolism MH - Chickens MH - Transport MH - Pattern. AB - Like males of many bird species, male House Finches (Carpodacus mexicanus) have patches of feathers with ornamental coloration that are due to carotenoid pigments. Within populations, male House Finches vary in expression of ornamental coloration from pale yellow to bright red, which previous research suggested was the result of variation in types and amounts of carotenoid pigments deposited in feathers. Here we used improved analytical techniques to describe types and amounts of carotenoid pigments present in that plumage. We then used those data to make comparisons of carotenoid composition of feathers of male House Finches at three levels: among individual males with different plumage hue and saturation, between age groups of males from the same population, and between males from two subspecies that differ in extent of ventral carotenoid pigmentation (patch size): large-patched C. in. frontalis from coastal California and small-patched C. in. griscomi from Guerrero, Mexico. In all age groups and populations, the ornamental plumage coloration of male House Finches resulted from the same 13 carotenoid pigments, with 3-hydroxy echinenone and lutein being the most abundant carotenoid pigments. The composition of carotenoids in feathers suggested that House Finches are capable of metabolic transformation of dietary forms of carotenoids. The hue of male plumage depended on component carotenoids, their relative concentrations, and total concentration of all carotenoids. Most 4-keto (red) carotenoids were positively correlated with plumage redness, and most yellow carotenoid pigments were negatively associated with plumage redness, although the strength of the relationship for specific carotenoid pigments varied among age groups and subspecies. Using age and subspecies as factors and concentration of each component carotenoid as dependent variables in a MANOVA, we found a distinctive pigment profile for each age group within each subspecies. Among frontalis males, hatch-year birds did not differ from adults in mean plumage hue, but they had a significantly lower proportion of red pigments in their plumage, and significantly lower levels of the red piments adonirubin and astaxanthin, but significantly higher levels of the yellow pigment zeaxanthin, than adult males. Among griscomi males, hatch-year birds differed from adults in plumage hue but not significantly in pigment composition, though in general their feathers had lower concentrations of red pigments and higher concentrations of yellow pigments than adult males. Both adult and hatch-year frontalis males differed from griscomi males in having significantly higher levels of most yellow carotenoid pigments and significantly lower levels of most red carotenoid pigments. Variation in pigment profiles of subspecies and age classes may reflect differences among the groups in carotenoid metabolism, in dietary access to carotenoids, or in exposure to environmental factors, such as parasites, that may affect pigmentation. [References: 60] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Animal Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Hill GE Auburn Univ, Dept Biol Sci 331 Funchess Hall Auburn, AL 36849 USA Auburn Univ, Dept Biol Sci Auburn, AL 36849 USA Auburn Univ, Alabama Agr Expt Stn Auburn, AL 36849 USA Univ Calif Los Angeles, Dept Organism Biol Ecol & Evolut Los Angeles, CA 90095 USA Univ Milan, Inst Chim Organ I-20133 Milan MI Italy Queens Univ, Dept Biol Kingston ON K7L 3N6 Canada <72> UI - 493CJ-0009 DD - ISI Document Solution: 493CJ AU - Kromkamp JC AU - Domin A AU - Dubinsky Z AU - Lehmann C AU - Schanz F MA - kromkamp@cemi.nioo.knaw.nl RA - Kromkamp JC TI - Changes in photosynthetic properties measured by oxygen evolution and variable chlorophyll fluorescence in a simulated entrainment experiment with the cyanobacterium Planktothrix rubescens SO - Aquatic Sciences. 63(3):363-382, 2001. AS - Aquat. Sci 2001;63(3):363-382 PU - BIRKHAUSER VERLAG AG, VIADUKSTRASSE 40-44, PO BOX 133, CH-4010 BASEL, SWITZERLAND. URL: http://www.birkhauser.ch IS - 1015-1621 MH - Entrainment MH - Planktothrix rubescens MH - Variable chlorophyll fluorescence MH - Photosynthesis MH - Photosystem ii MH - Quantum requirement MH - Lake zurich. MH - Electron-transport MH - Quantum yield MH - Lake-zurich MH - Phytoplankton photosynthesis MH - Carbon assimilation MH - Eukaryotic algae MH - Photosystem-ii MH - Depth MH - Dependence MH - Irradiance. AB - The metalimnion of lake Zurich is dominated by the red coloured cyanobacterium Planktotrix rubescens, where it lives in an extremely low light environment. Photosynthesis of the organism was studied using oxygen evolution and variable fluorescence. After transfer to 2 in depth in the epilimnion. simulating an entrainment event that normally occurs in late summer, photoacclimation was followed. The metalimnetic population had a very high photosynthetic efficiency, and the minimum quantum requirement varied between 7-12 photons (mol O-2)(-1). Upon transfer to high light the quantum requirement increased, which was interpreted as inactivation of a number of photosystem II (PSII) units. At the first entrainment we observed only inactivation of PSII, causing a decrease in the slope of the photosynthesis light curve (both for oxygen evolution and photosynthetic electron transport by PSII (ETR)), without affecting the maximal rate of oxygen evolution (PBmaxB), suggesting no effect on CO2-fixation. During the 2(nd) entrainment experiment we observed both an inactivation of the number of PSII as well as a decrease in P-max(B). In both cases the ETR-based estimates of oxygen evolution (P-B) overestimated the measured rate of P-B, indicating the operation of alternative electron sinks. Especially at high light respiratory processes were seemingly stimulated. [References: 32] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Aquatic Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2001 week 50 IN - Reprint available from: Kromkamp JC NIOO, Ctr Estuarine & Coastal Ecol POB 140 NL-4400 AC Yerseke Netherlands NIOO, Ctr Estuarine & Coastal Ecol NL-4400 AC Yerseke Netherlands Univ Leipzig, Inst Allgemeine Bot D-04103 Leipzig Germany Bar Ilan Univ, Dept Life Sci IL-52100 Ramat Gan Israel Univ Zurich, Inst Pflanzenbiol, Limnol Stn CH-8802 Zurich Switzerland