<1> UI - 553LM-0010 DD - ISI Document Solution: 553LM AU - Naidoo G AU - Tuffers AV AU - von Willert DJ MA - gnaidoo@pixie.udw.ac.za RA - Naidoo G TI - Changes in gas exchange and chlorophyll fluorescence characteristics of two mangroves and a mangrove associate in response to salinity in the natural environment SO - Trees-Structure & Function. 16(2-3):140-146, 2002 Mar. AS - Trees-Struct. Funct 2002 Mar;16(2-3):140-146 PU - SPRINGER-VERLAG, 175 FIFTH AVE, NEW YORK, NY 10010 USA. URL: http://www.springer-ny.com IS - 0931-1890 MH - A. marina MH - B. gymnorrhiza MH - H. tiliaceus MH - Photosynthesis MH - Fluorescence. MH - Photosynthetic electron-transport MH - Avicennia-marina MH - Field conditions MH - Salt tolerance MH - Leaf angle MH - Leaves MH - Photoinhibition MH - Drought MH - Light MH - Photoprotection. AB - Photosynthetic responses of two mangroves and a mangrove associate were investigated in a low salinity site at Beachwood (<12parts per thousand) and a high salinity site at Durban Bay (35parts per thousand). Measurements were made of CO2 exchange, chlorophyll fluorescence, ion and water relations of Avicennia marina, Bruguiera gymnorrhiza and Hibiscus tiliaceus at the two sites. At Beachwood, CO, exchange was highest in H. tiliaceus (9.12 mumol m(-2)s(-1)) and least in A. marina (3.27 mumol m(-2)s(-1)). At the Durban Bay site, CO2 exchange in A. marina was greater than that at Beachwood by 79%, that in H. tiliaceus decreased by 59% while that in B. gymnorrhiza remained unchanged. In all species, photosystem II (PSII) quantum yield decreased with increase in photon flux density (PFD) up to 2,000 mumol m(-2)s(-1). Electron transport rate (ETR) through PSII increased with increase in PFD, reaching saturation at 1000 mumol m(-2)s(-1). At saturating PFD, PSII quantum yield and ETR were higher in the mangroves but lower in H. tiliaceus at the high salinity site. Photochemical and non-photochemical quenching were, however, lower in the mangroves but higher in H. tiliaceus at the high salinity site. Predawn and midday leaf water potential were higher at Beachwood and significantly reduced at Durban Bay, values being highest in H. tiliaceus (-0.4 and -1.8 MPa) and least in A. marina (-2.5 and -3.8 MPa). Leaf concentrations of Na+, Cl-, Ca2+ and Mg2+ in mangroves were significantly higher at Durban Bay than at Beachwood. In H. tiliaceus there were no differences in ion concentrations between sites except for K+, which was significantly higher at Durban Bay. [References: 38] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Naidoo G Univ Durban Westville, Dept Bot Private Bag X54001 ZA-4000 Durban South Africa Univ Durban Westville, Dept Bot ZA-4000 Durban South Africa Univ Munster, Inst Okol Pflanzen D-48143 Munster Germany <2> UI - 554BW-0007 DD - ISI Document Solution: 554BW AU - Richardson AD AU - Berlyn GP MA - andrew.richardson@yale.edu RA - Richardson AD TI - Changes in foliar spectral reflectance and chlorophyll fluorescence of four temperate species following branch cutting SO - Tree Physiology. 22(7):499-506, 2002 May. AS - Tree Physiol 2002 May;22(7):499-506 PU - HERON PUBLISHING, 202, 3994 SHELBOURNE ST, VICTORIA, BC V8N 3E2, CANADA. URL: http://www.heronpublishing.com IS - 0829-318X MH - Abies balsamea MH - Balsam fir MH - Betula papyrifera MH - F-v/f-m MH - Leaf reflectance MH - Mountain-ash MH - Paper birch MH - Picea rubens MH - Red spruce MH - Sorbus americana MH - Stress. MH - Radiation-use efficiency MH - Stomatal conductance MH - Plant stress MH - Red spruce MH - Leaves MH - Photosynthesis MH - Index MH - Autumn MH - Pine MH - Edge. AB - Spectral reflectance and chlorophyll fluorescence are rapid non-invasive methods that can be used to quantify plant stress. Because variation in ambient light (e.g., diurnal patterns of solar radiation) may have a confounding effect on these measurements, branches are often excised in the field and then measured under controlled conditions in the laboratory. We studied four temperate tree species (Abies balsamea (L.) Mill. (balsam fir), Betula papyrifera var. cordifolia (Regel) Fern. (paper birch), Picea rubens Sarg. (red spruce) and Sorbus americana Marsh. (mountain-ash)) to determine how quickly reflectance and fluorescence change following branch cutting. We hypothesized that conifer species, which have tough xeromorphic foliage, would exhibit changes more slowly than broadleaf species. Furthermore, we hypothesized that keeping broadleaf samples cool and moist would delay the onset of reflectance and fluorescence changes. In one set of experiments, we did not use any treatments to maintain the freshness of cut branches. During the first 12 h following cutting, changes in reflectance and fluorescence were slight for all species. Two or 3 days after branch cutting, the two conifers still showed only small changes in the ratio of variable to maximum fluorescence (F-v/F-m) and most reflectance indices, whereas paper birch and mountain-ash showed larger and more rapid declines in F-v/F-m and most reflectance indices. We attribute these declines to loss of water. As a consequence of xeromorphic leaf structure, the conifers were better able to minimize water loss than the two broadleaf species. In another experiment, paper birch that had been kept cool and moist after cutting showed only slight changes in fluorescence and reflectance, even after 3 days, indicating that with careful handling the time interval between collection and measurement of reflectance and fluorescence of many broadleaf specimens can be extended to several days. We conclude that measurements of reflectance and fluorescence need not be made in situ to be accurate and reliable. [References: 36] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Richardson AD Yale Univ, Sch Forestry & Environm Studies 370 Prospect St New Haven, CT 06511 USA Yale Univ, Sch Forestry & Environm Studies New Haven, CT 06511 USA <3> UI - 553BW-0020 DD - ISI Document Solution: 553BW AU - Iwaki M AU - Andrianambinintsoa S AU - Rich P AU - Breton J MA - cadara3@dsvidf.cea.fr RA - Breton J TI - Attenuated total reflection Fourier transform infrared spectroscopy of redox transitions in photosynthetic reaction centers: comparison of perfusion- and light-induced difference spectra SO - Spectrochimica Acta Part A-Molecular Spectroscopy. 58(7):1523-1533, 2002 May. AS - Spectroc. Acta Pt. A-Molec. Biomolec. Spectr 2002 May;58(7):1523-1533 PU - PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND. URL: http://www.elsevier.nl IS - 1386-1425 MH - Fourier transform infrared difference spectroscopy MH - Photosynthetic reaction center MH - Attenuated total reflection. MH - Bacterial reaction centers MH - Primary electron-donor MH - Viridis reaction centers MH - Cytochrome-c-oxidase MH - Rhodobacter-sphaeroides MH - Photosystem-i MH - Ftir spectroscopy MH - Binding-sites MH - C-13-labeled ubiquinone MH - Structural-changes. AB - Chemically induced Fourier transform infrared difference spectra associated with redox transitions of several primary electron donors and acceptors in photosynthetic reaction centers (RCs) have been compared with the light-induced FTIR difference spectra involving the same cofactors. The RCs are deposited on an attenuated total reflection (ATR) prism and form a film that is enclosed in a flow cell. Redox transitions in the film of RCs can be repetitively induced either by perfusion of buffers poised at different redox potentials or by illumination. The perfusion-induced ATR-FTIR difference spectra for the oxidation of the primary electron donor P in the RCs of the purple bacteria Rb. sphaeroides and Rp. viridis and P700 in the photosystem I of Synechoeystis 6803, as well as the Q(A)(-)/Q(A) transition of the quinone acceptor (Q(A)) in Rb. sphaeroides RCs are reported for the first time. They are compared with the light-induced ATR-FTIR difference spectra P(+)Q(A)(-)/PQ(A) for the RCs of Rb. sphaeroides and P700+/P700 for photosystem 1. It is shown that the perfusion-induced and light-induced ATR-FTIR difference spectra recorded on the same RC film display identical signal to noise ratios when they are measured under comparable conditions. The ATR-FTIR difference spectra are very similar to the equivalent FTIR difference spectra previously recorded upon photochemical or electrochemical excitation of these RCs in the more conventional transmission mode. The ATR-FTIR technique requires a smaller amount of sample compared with transmission FTIR and allows precise control of the aqueous environment of the RC films. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 56] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Spectroscopy/Instrumentation/Analytical Sciences in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2002 week 24 IN - Reprint available from: Breton J CEA Saclay, DBCM, SBE Bat 532 F-91191 Gif Sur Yvette France CEA Saclay, DBCM, SBE F-91191 Gif Sur Yvette France Univ London Univ Coll, Dept Biol London WC1E 6BT England <4> UI - 554DN-0007 DD - ISI Document Solution: 554DN AU - Czerpak R AU - Dobrzyn P AU - Krotke A AU - Kicinska E RA - Czerpak R TI - The effect of auxins and salicylic acid on chlorophyll and carotenoid contents in Wolffia arrhiza (L.) Wimm. (Lemnaceae) growing on media of various trophicities SO - Polish Journal of Environmental Studies. 11(3):231-235, 2002. AS - Pol. J. Environ. Stud 2002;11(3):231-235 PU - HARD, POST-OFFICE BOX, 10-718 OLSZTYN 5, POLAND IS - 1230-1485 MH - Wolffia arrhiza MH - Nutrient availability MH - Pigments MH - Salicylic acid MH - Auxins. MH - Performance liquid-chromatography MH - Chlorella-pyrenoidosa chick MH - Growth MH - Pigments MH - Plants. AB - In Wolffia arrhiza (Lemnaceae) growing on municipal tap water (rich in mineral but poor in organic components) and thus being exclusively photoautotrophic, IAA (3-indolilacetic acid) and SA (salicylic acid) strongly stimulated action on the content of chlorophylls a and b and carotenoids (especially P-carotene and lutein + zeaxanthin). On the other hand, the chemical analogues of IAA, i.e. PAA (phenylacetic acid) and NAA (alpha-naphtylacetic acid), had a generally inhibitory effect on chlorophyll and carotenoid contents. In Wolffia arrhiza growing on raw waste water and a suspension of activated sludge from a sewage treatment plant (rich in organic substances) characterized by mixotrophism (that is photo- and heterotrophism) PAA had the highest stimulative action on the chlorophyll a and b content, SA negligible, whereas NAA had an inhibitory effect. IAA had a slight stimulative effect on raw sewage but inhibitory on activated sludge. Also, the greatest stimulative effect on carotenoids content was exerted by PAA; SA had a slight stimulative effect while IAA and, to a greater extent NAA had a clearly inhibitory influence. [References: 20] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Environment/Ecology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Czerpak R Univ Bialystok, Inst Biol Swierkowa 20B PL-15950 Bialystok Poland Univ Bialystok, Inst Biol PL-15950 Bialystok Poland Polish Acad Sci, Inst Ecol PL-05092 Lomianki Poland <5> UI - 553EQ-0001 DD - ISI Document Solution: 553EQ AU - Takeuchi A AU - Yamaguchi T AU - Hidema J AU - Strid A AU - Kumagai T MA - kumagai@ige.tohoku.ac.jp RA - Kumagai T TI - Changes in synthesis and degradation of Rubisco and LHCII with leaf age in rice (Oryza sativa L.) growing under supplementary UV-B radiation SO - Plant, Cell & Environment. 25(6):695-706, 2002 Jun. AS - Plant Cell Environ 2002 Jun;25(6):695-706 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0140-7791 MH - Oryza sativa l. MH - Leaf age MH - Light-harvesting chlorophyll a/b binding protein of psii MH - Protein synthesis and degradation MH - Ribulose-1 MH - 5-bisphosphate carboxylase/oxigenase MH - Transcription regulation MH - Ultraviolet-b radiation. MH - Ribulose 1,5-bisphosphate carboxylase MH - Messenger-rna transcripts MH - Pisum-sativum MH - Ribulose-1,5-bisphosphate carboxylase/oxygenase MH - Large subunit MH - 280-320 nm MH - Electrochromic shifts MH - Different irradiances MH - Japanese lowland MH - Gene-expression. AB - The effects of supplementary ultraviolet-B (UV-B) radiation on the changes in synthesis and degradation of ribulose -1,5-bisphosphate carboxylase/oxygenase (Rubisco) and light-harvesting chlorophyll a /b binding protein of PSII (LHCII) were examined, as well as mRNA levels for small and large subunits of Rubisco (rbcS and rbcL , respectively) and LHCII (cab ) with leaf age in UV-sensitive rice (Norin 1) and UV-resistant rice (Sasanishiki). Both Rubisco and LHCII were actively synthesized until the leaf had fully expanded, and then decreased with increasing leaf age. Synthesis of Rubisco, but not LHCII, was significantly suppressed by UV-B in Norin 1. The degradation of Rubisco was enhanced by UV-B around the time of leaf maturation in the two cultivars. The levels of rbcS and rbcL were reduced by UV-B at the early stages after leaf emergence in both cultivars. Cab transcripts were first present at high levels in the two cultivars, but drastically decreased due to UV-B treatment immediately after leaf emergence in Norin 1. It was shown that synthesis and degradation of Rubisco and LHCII greatly changed with leaf age: Rubisco synthesis was significantly suppressed by supplementary UV-B radiation at the transcription step during the early leaf stages. It was also suggested that the difference in UV-B sensitivity in Rubisco synthesis between the two rice cultivars might be due to specific suppression both transcriptionally and post-transcriptionally. [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 - 2002 week 24 IN - Reprint available from: Kumagai T Tohoku Univ, Grad Sch Life Sci, Dept Environm Life Sci Sendai Miyagi 9808577 Japan Tohoku Univ, Grad Sch Life Sci, Dept Environm Life Sci Sendai Miyagi 9808577 Japan Univ Gothenburg, Dept Chem S-40530 Gothenburg Sweden Univ Orebro, Dept Nat Sci S-70182 Orebro Sweden <6> UI - 553EQ-0005 DD - ISI Document Solution: 553EQ AU - Beligni MV AU - Lamattina L MA - lolama@mdp.edu.ar RA - Lamattina L TI - Nitric oxide interferes with plant photo-oxidative stress by detoxifying reactive oxygen species SO - Plant, Cell & Environment. 25(6):737-748, 2002 Jun. AS - Plant Cell Environ 2002 Jun;25(6):737-748 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0140-7791 MH - Antioxidant enzymes MH - D-1 protein MH - Lipid peroxidation MH - Nitric oxide MH - Oxidative stress MH - Protein oxidation MH - Reactive oxygen species MH - Rna degradation MH - Rubisco. MH - Ribulose-1,5-bisphosphate carboxylase oxygenase MH - Solanum-americanum MH - Cellular-damage MH - Paraquat MH - Radicals MH - Protects MH - Ozone MH - No MH - Chloroplasts MH - Degradation. AB - Oxidative stress within chloroplasts is originated due to light-dependent O-2 reduction. This may be exacerbated by bipyridinium herbicides, which act at photosystem I as artificial electron acceptors. Their oxidation produces a superoxide anion that further dismutates to H2O2 and then, by the Fenton reaction, H2O2 may be reduced to the hydroxyl radical (OH.). Reactive oxygen species (ROS), when produced in high amounts, provoke severe damage to the plant cell. Herein it is reported that two nitric oxide (NO) donors, sodium nitroprusside (100 mum) and S-nitroso-N-acetylpenicillamine (200 mum), greatly reduced lipid peroxidation and the protein loss caused by the application of a high dose of the bipyridinium herbicide diquat to potato leaf pieces or isolated chloroplasts. Nitric oxide donors also protected the RNA against oxidative damage. Photo-oxidative toxicity was correlated with an increase in photosynthetic electron transport and ROS production, but the rate of electron transport was restored and the ROS free amount was markedly reduced in the presence of NO. The specific activity of superoxide dismutase was not affected by diquat or NO donors, whereas just a small increase in catalase activity was observed after 24 h of treatment. These results provide strong evidence that NO is a potent antioxidant in plants and that its action may, at least in part, be explained by its ability to directly scavenge ROS. [References: 45] 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 - 2002 week 24 IN - Reprint available from: Lamattina L Univ Mar del Plata, Fac Ciencias Exactas & Nat, Inst Invest Biol CC 1245 RA-7600 Mar Del Plata Argentina Univ Mar del Plata, Fac Ciencias Exactas & Nat, Inst Invest Biol RA-7600 Mar Del Plata Argentina <7> UI - 553EQ-0006 DD - ISI Document Solution: 553EQ AU - Valladares F AU - Pearcy RW MA - valladares@ccma.csic.es RA - Valladares F TI - Drought can be more critical in the shade than in the sun: a field study of carbon gain and photo-inhibition in a Californian shrub during a dry El Nino year SO - Plant, Cell & Environment. 25(6):749-759, 2002 Jun. AS - Plant Cell Environ 2002 Jun;25(6):749-759 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0140-7791 MH - Heteromeles arbutifolia MH - Chlorophyll fluorescence MH - Drought MH - Light utilization efficiency MH - Mediterranean-type ecosystems MH - Photo-inhibition MH - Photosynthesis MH - Stomatal conductance MH - Sunflecks MH - Water potential. MH - Heteromeles arbutifolia MH - High light MH - Photosynthetic apparatus MH - Arisaema-heterophyllum MH - Leaf photosynthesis MH - Co2 assimilation MH - Photoinhibition MH - Photorespiration MH - Stress MH - Leaves. AB - Diurnal courses of leaf water potential (Psi(l)), gas exchange and chlorophyll fluorescence were measured in natural sun and shade populations of Heteromeles arbutifolia throughout the seasons of an unusually dry El Nino year in Central California. The onset of drought resulted in decreased stomatal conductance and net photosynthesis in both sun and shade plants. However, the decline in Psi(l) was much greater and carbon gain was much more strongly limited by the development of drought stress in the shade than in the sun. Photorespiratory energy dissipation was significantly higher in the sun than in the shade in spring and autumn, but not during the summer. Pre-dawn photochemical efficiency (F-v/F-m) was significantly higher in the shade than in the sun during the spring but the differences disappeared during the summer and autumn. The strong irradiance in the open field site studied led to a chronic but only mild reduction in F-v/F-m, with values around 0.79. Summer sunflecks led to a sustained photo-inhibition in shade plants, which exhibited a significant reduction in pre-dawn F-v/F-m of 10% with the onset of drought. Photo-inhibition became relatively more important for carbon gain in the shade than in the sun due to the low photochemical efficiency under the low light that follows sunflecks. Sun plants of H. arbutifolia exhibited a rather efficient photoprotection against strong irradiance conferred by both the architecture of the crown and the physiology of the leaves. There is evidence that El Nino events and the associated droughts have become more frequent and severe. Counter-intuitively, the effects on plant performance of such extreme droughts could be more critical in the shade than in the sun. [References: 51] 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 - 2002 week 24 IN - Reprint available from: Valladares F CSIC, Ctr Ciencias Medioambientales Serrano 115 Dpdo E-28006 Madrid Spain CSIC, Ctr Ciencias Medioambientales E-28006 Madrid Spain Univ Calif Davis, Sect Evolut & Ecol Davis, CA 95616 USA <8> UI - 553EQ-0007 DD - ISI Document Solution: 553EQ AU - Savitch LV AU - Leonardos ED AU - Krol M AU - Jansson S AU - Grodzinski B AU - Huner NPA AU - Oquist G MA - gunnar.oquist@plantphys.umu.se RA - Oquist G TI - Two different strategies for light utilization in photosynthesis in relation to growth and cold acclimation SO - Plant, Cell & Environment. 25(6):761-771, 2002 Jun. AS - Plant Cell Environ 2002 Jun;25(6):761-771 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0140-7791 MH - Pinus contorta MH - Triticum aestivum MH - Cold acclimation MH - Dormancy MH - Evergreen MH - Frost hardening MH - Photo-inhibition MH - Photosynthesis MH - Psbs protein MH - Xanthophyll cycle. MH - Pine pinus-sylvestris MH - Pigment-binding protein MH - Winter-wheat MH - Scots pine MH - Energy-dissipation MH - Xanthophyll cycle MH - Seasonal-changes MH - Low-temperature MH - Photoinhibition MH - Rye. AB - Seedlings of Lodgepole pine (Pinus contorta L.) and winter wheat (Triticum aestivum L. cv. Monopol) were cold acclimated under controlled conditions to induce frost hardiness. Lodgepole pine responded to cold acclimation by partial inhibition of photosynthesis with an associated partial loss of photosystem II reaction centres, and a reduction in needle chlorophyll content. This was accompanied by a low daily carbon gain, and the development of a high and sustained capacity for non-photochemical quenching of absorbed light. This sustained dissipation of absorbed light as heat correlated with an increased de-epoxidation of the xanthophyll cycle pigments forming the quenching forms antheraxanthin and zeaxanthin. In addition, the PsbS protein known to bind chlorophyll and the xanthophyll cycle pigments increased strongly during cold acclimation of pine. In contrast, winter wheat maintained high photosynthetic rates, showed no loss of chlorophyll content per leaf area, and exhibited a high daily carbon gain and a minimal non-photochemical quenching after cold acclimation. In accordance, cold acclimation of wheat neither increased the de-epoxidation of the xanthophylls nor the content of the PsbS protein. These different responses of photosynthesis to cold acclimation are correlated with pine, reducing its need for assimilates when entering dormancy associated with termination of primary growth, whereas winter wheat maintains a high need for assimilates as it continues to grow and develop throughout the cold-acclimation period. It appears that without evolving a sustained ability for controlled dissipation of absorbed light as heat throughout the winter, winter green conifers would not have managed to adapt and establish themselves so successfully in the cold climatic zones of the northern hemisphere. [References: 41] 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 - 2002 week 24 IN - Reprint available from: Oquist G Umea Univ, Dept Plant Physiol, Umea Plant Sci Ctr S-90187 Umea Sweden Umea Univ, Dept Plant Physiol, Umea Plant Sci Ctr S-90187 Umea Sweden Univ Western Ontario, Dept Plant Sci London ON N6A 5B7 Canada Univ Guelph, Dept Plant Agr Guelph ON N1G 2W1 Canada <9> UI - 552PA-0013 DD - ISI Document Solution: 552PA AU - Burke DJ AU - Hamerlynck EP AU - Hahn D MA - djburke@pegasus.rutgers.edu RA - Burke DJ TI - Effect of arbuscular mycorrhizae on soil microbial populations and associated plant performance of the salt marsh grass Spartina patens SO - Plant & Soil. 239(1):141-154, 2002 Feb. AS - Plant Soil 2002 Feb;239(1):141-154 PU - KLUWER ACADEMIC PUBL, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS. URL: http://www.wkap.nl IS - 0032-079X MH - Chlorophyll fluorescence MH - In situ hybridization MH - Microbial diversity MH - Nifh MH - Nitrogen-fixing bacteria MH - Oligonucleotide probes MH - Rrna. MH - Diazotroph assemblage composition MH - Natural bacterial communities MH - Nonmycorrhizal control MH - Nitrogen-fixation MH - Rhizosphere MH - Carbon MH - Hybridization MH - Alterniflora MH - Exudation MH - Biomass. AB - The effect of arbuscular mycorrhizae (AM) on soil microbial populations and on growth performance of the high salt marsh plant Spartina patens was investigated in a AM suppression study on field-collected soil cores with S. patens. The application of benomyl resulted in a significant reduction of AM colonization on roots of S. patens, but did not completely suppress AM. Non-treated cores had significantly greater colonization (26+/-6%) than either benomyl-(12+/-7%) or benomyl-phosphorus-treated (7+/-3%) cores at a depth of 2.5 cm. Colonization differences between cores declined with depth (5.0 and 7.5 cm). however, so that at 7.5 cm there was no difference between treatments. This decline was attributed to a reduction in oxygen availability with depth as evidenced by decreasing redox potential. Basic environmental conditions generally resembled those found at the field site. There were no environmental differences between treatments at the depths examined. Cell numbers and specific biomass of DAPI-stained organisms as well as members of the Domain Bacteria were significantly higher when AM colonization was suppressed. while those of the Domains Eucarya and Archaea were not significantly influenced. The increase in both microbial and bacterial population size and biomass in the presence of lower levels of AM colonization is most likely due to increases in carbon exudation to soil and rhizosphere populations that accompany AM suppression. PCR-RFLP analysis of nifH amplicons in bulk soil and rhizosphere at varying depths through the soil cores showed differences in banding patterns between rhizosphere and soil material in the presence of AM. The lack of such strong differences in the benomyl-treated cores suggests that AM colonization more strongly affects the nitrogen-fixing population than do physicochemical conditions (e.g. redox potential) alone. Plant growth performance assessed by analyzing root and leaf biomass, as well as excitation transfer efficiency of open photosynthesis system II (PS II) reaction centers (Fv/Fm) was not significantly influenced by AM. Significant differences were found between treatments for C/N ratios and nitrogen content in leaf tissue. indicating that suppression of AM increased plant nitrogen acquisition. [References: 61] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Environment/Ecology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Burke DJ Rutgers State Univ, Dept Biol Sci 101 Warren St,Smith Hall 135 Newark, NJ 07102 USA Rutgers State Univ, Dept Biol Sci Newark, NJ 07102 USA New Jersey Inst Technol, Dept Chem Engn Newark, NJ 07102 USA <10> UI - 553ZT-0030 DD - ISI Document Solution: 553ZT AU - Lakhno VD RA - Lakhno VD TI - Oscillations in the primary charge separation in bacterial photosynthesis SO - Physical Chemistry Chemical Physics. 4(11):2246-2250, 2002. AS - Phys. Chem. Chem. Phys 2002;4(11):2246-2250 PU - ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND. URL: http://www.rsc.org IS - 1463-9076 MH - Primary electron-transfer MH - Reaction centers MH - Rhodobacter-sphaeroides MH - Femtosecond spectroscopy MH - Numerical experiments MH - Absorption lineshape MH - Lattice-vibrations MH - Molecular wires MH - Primary donor MH - Mechanism. AB - This paper examines the temporal evolution of an electron in a photosynthetic reaction center. A model based on self-consistent quantum-mechanical equations is suggested to describe the picosecond transfer of an electron from an excited primary donor, the excited bacteriochlorophyll dimer (P*), to bacteriopheophytin ( H). This transfer is shown to have an oscillation behavior. The results obtained offer an explanation for oscillations in the emission kinetics of the primary donor excited state. [References: 31] 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 - 2002 week 24 IN - Reprint available from: Lakhno VD Russian Acad Sci, Inst Math Problems Biol Pushchino 142290 Moscow Region Russia Russian Acad Sci, Inst Math Problems Biol Pushchino 142290 Moscow Region Russia <11> UI - 552FW-0002 DD - ISI Document Solution: 552FW AU - Brusque AM AU - Rosa RB AU - Schuck PF AU - Dalcin KB AU - Ribeiro CAJ AU - Silva CG AU - Wannmacher CMD AU - Dutra CS AU - Wyse ATS AU - Briones P AU - Wajner M MA - mwajner@vortex.ufrgs.br RA - Wajner M TI - Inhibition of the mitochondrial respiratory chain complex activities in rat cerebral cortex by methylmalonic acid SO - Neurochemistry International. 40(7):593-601, 2002 Jun. AS - Neurochem. Int 2002 Jun;40(7):593-601 PU - PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND. URL: http://www.elsevier.nl IS - 0197-0186 MH - Propionic acid MH - Methylmalonic acid MH - Respiratory chain MH - Propionic acidemia MH - Methylmalonic acidemia. MH - 3-hydroxyacyl-coa dehydrogenase-deficiency MH - Human skeletal-muscle MH - 3-nitropropionic acid MH - Energy-metabolism MH - Propionic-acid MH - Neurological dysfunction MH - Succinate-dehydrogenase MH - Parkinsons-disease MH - Suckling rats MH - Brain. AB - Propionic and methylmalonic acidemic patients have severe neurologic symptoms whose etiopathogeny is still obscure. Since increase of lactic acid is detected in the urine of these patients, especially during metabolic decompensation when high concentrations of methylmalonate (MMA) and propionate (PA) are produced, it is possible that cellular respiration may be impaired in these individuals. Therefore, we investigated the effects of NIMA and PA (1, 2.5 and 5 mM), the principal metabolites which accumulate in these conditions, on the mitochondrial respiratory chain complex activities succinate: 2,6-dichloroindophenol (DCIP) oxireductase (complex II); succinate: cytochrome c oxireductase (complex II + CoQ + III); NADH: cytochrome c oxireductase (complex I + CoQ + complex III); and cytochrome c oxidase (COX) (complex IV) from cerebral cortex homogenates of young rats. The effect of NIMA on ubiquinol: cytochrome c oxireductase (complex III) and NADH: ubiquitione oxireductase (complex I) activities was also tested. Control groups did not contain MMA and PA in the incubation medium. MMA significantly inhibited complex I + III (32-46%), complex I (61-72%), and complex II + III (15-26%), without affecting significantly the activities of complexes II, III and IV. However, by using I mM succinate in the assay instead of the usual 16 mM concentration, MMA was able to significantly inhibit complex II activity in the brain homogenates. In contrast, PA did not affect any of these mitochondrial enzyme activities. The effect of MMA and PA on succinate: phenazine oxireductase (soluble succinate dehydrogenase (SDH)) was also measured in mitochondrial preparations. The results showed significant inhibition of the soluble SDH activity by MMA (11-27%) in purified mitochondrial fractions. Thus, if the in vitro inhibition of the oxidative phosphorylation system is also expressed under in vivo conditions, a deficit of brain energy production might explain some of the neurological abnormalities found in patients with methylmalonic acidemia (MMAemia) and be responsible for the lactic acidemia/aciduria identified in some of them. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 46] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Neurosciences & Behavior in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Wajner M UFRGS, Inst Ciencias Basicas Saude, Dept Bioquim Rua Ramiro Barcelos 2600 BR-90035003 Porto Alegre RS Brazil UFRGS, Inst Ciencias Basicas Saude, Dept Bioquim BR-90035003 Porto Alegre RS Brazil Hosp Clin Porto Alegre, Serv Genet Med Porto Alegre RS Brazil Inst Bioquim Clin Barcelona Spain <12> UI - 556QK-0036 DD - ISI Document Solution: 556QK AU - Herek JL AU - Wohlleben W AU - Cogdell RJ AU - Zeidler D AU - Motzkus M MA - mcm@mpq.mpg.de RA - Motzkus M TI - Quantum control of energy flow in light harvesting SO - Nature. 417(6888):533-535, 2002 May 30. AS - Nature 2002 May 30;417(6888):533-535 PU - NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND. URL: www.nature.com IS - 0028-0836 MH - Laser-pulses MH - Photosynthetic unit MH - Phase MH - Frequency MH - Bacteria MH - Complex MH - Domain MH - Lh2. AB - Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes. The adaptive shaping of laser pulses is a particularly powerful tool in this context: experimental output as feedback in an iterative learning loop refines the applied laser field to render it best suited to constraints set by the experimenter(1,2). This approach has been experimentally implemented to control a variety of processes(3-9), but the extent to which coherent excitation can also be used to direct the dynamics of complex molecular systems in a condensed-phase environment remains unclear. Here we report feedback-optimized coherent control over the energy-flow pathways in the light-harvesting antenna complex LH2 from Rhodopseudomonas acidophila, a photosynthetic purple bacterium. We show that phases imprinted by the light field mediate the branching ratio of energy transfer between intra- and intermolecular channels in the complex's donor-acceptor system. This result illustrates that molecular complexity need not prevent coherent control, which can thus be extended to probe and affect biological functions. [References: 30] 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 - 2002 week 24 IN - Reprint available from: Motzkus M Max Planck Inst Quantum Opt D-85748 Garching Germany Max Planck Inst Quantum Opt D-85748 Garching Germany Lund Univ S-22100 Lund Sweden Vrije Univ Amsterdam, Dept Biophys NL-1081 HV Amsterdam Netherlands Univ Glasgow, IBLS, Div Biochem & Mol Biol Glasgow G12 8QQ Lanark Scotland <13> UI - 556QK-0046 DD - ISI Document Solution: 556QK AU - Gupta R AU - He ZY AU - Luan S MA - sluan@nature.berkeley.edu RA - Luan S TI - Functional relationship of cytochrome c(6) and plastocyanin in Arabidopsis SO - Nature. 417(6888):567-571, 2002 May 30. AS - Nature 2002 May 30;417(6888):567-571 PU - NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND. URL: www.nature.com IS - 0028-0836 MH - Protein phosphatase MH - Gene-expression MH - Photosystem-i MH - Synechocystis-6803 MH - Plants MH - Copper MH - Cyanobacterium MH - Chlamydomonas MH - Specificity MH - Thaliana. AB - Photosynthetic electron carriers are important in converting light energy into chemical energy in green plants. Although protein components in the electron transport chain are largely conserved among plants, algae and prokaryotes, there is thought to be a major difference concerning a soluble protein in the thylakoid lumen. In cyanobacteria and eukaryotic algae, both plastocyanin and cytochrome c(6) mediate electron transfer from cytochrome b(6)f complex to photosystem I1-4. In contrast, only plastocyanin has been found to play the same role in higher plants. It is widely accepted that cytochrome c(6) has been evolutionarily eliminated from higher-plant chloroplasts(5,6). Here we report characterization of a cytochrome c(6)-like protein from Arabidopsis (referred to as Atc6). Atc6 is a functional cytochrome c localized in the thylakoid lumen. Electron transport reconstruction assay showed that Atc6 replaced plastocyanin in the photosynthetic electron transport process. Genetic analysis demonstrated that neither plastocyanin nor Atc6 was absolutely essential for Arabidopsis growth and development. However, plants lacking both plastocyanin and Atc6 did not survive. [References: 27] 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 - 2002 week 24 IN - Reprint available from: Luan S Univ Calif Berkeley, Dept Plant & Microbial Biol Berkeley, CA 94720 USA Univ Calif Berkeley, Dept Plant & Microbial Biol Berkeley, CA 94720 USA <14> UI - 551XE-0006 DD - ISI Document Solution: 551XE AU - Figueroa FL AU - Jimenez C AU - Vinegla B AU - Perez-Rodriguez E AU - Aguilera J AU - Flores-Moya A AU - Altamirano M AU - Lebert M AU - Hader DP MA - felix_lopez@uma.es RA - Figueroa FL TI - Effects of solar UV radiation on photosynthesis of the marine angiosperm Posidonia oceanica from southern Spain SO - Marine Ecology-Progress Series. 230:59-70, 2002. AS - Mar. Ecol.-Prog. Ser 2002;230:59-70 PU - INTER-RESEARCH, NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY. URL: http://www.int-res.com IS - 0171-8630 MH - Marine angiosperms MH - Pam-fluorometry MH - Posidonia oceanica MH - Uv radiation. MH - Modulated pam fluorometry MH - Ultraviolet-b radiation MH - Chlorophyll fluorescence MH - Seagrass photosynthesis MH - Absorbing compounds MH - Depth distribution MH - Photosystem-ii MH - In-vivo MH - Photoinhibition MH - Macroalgae. AB - The effects of solar irradiance on the photosynthesis of the marine angiosperm Posidonia oceanica L. Delile were investigated by means of pulse amplitude - modulated (PAM) fluorescence in the Natural Park of Cabo de Gata-Nijar, southern Spain. The study was conducted in 2 different seasons, summer (September 1996) and winter (February 1997). Daily variation in the effective quantum yield (DeltaF/F-m') was determined in plants growing at 2.5 m and in plants transferred from 15 m to 0.5 and 2.5 m depth. Three different experimental designs were conducted: (1) Incubation of shoots under 3 different solar radiation treatments using cut-off UV filters: full solar radiation (PAR + UV-A + UV-B), solar radiation without UV-B (PAR + UV-A) and solar radiation without UV (PAR); (2) short-term exposure (30 min) to high solar irradiance (photoinhibitory phase) under all treatments followed by transfer fo the plants to low irradiance for 4 h (recovery phase); (3) Preincubation of plants for 4 d under the 3 cited treatments followed by short-term exposure (30 min) to high solar irradiance under PAR + UV-A + UV-B, PAR + UV-A and PAR. A significant decrease in DeltaF/F-m' occurred from dawn to noon (18% in September and only 6% in February), followed by total recovery during the afternoon in both seasons. The highest decrease in DeltaAF/F-m' occurred in shoots illuminated with PAR + UV-A radiation, This decrease was more pronounced in winter than in summer, and was substantially higher in plants transferred from deep (15 m) to shallow water than in plants harvested at 2.5 m. Moreover, the recovery in the afternoon was higher in plants incubated at 15 m than in those transferred from 15 m to shallow waters. In the second set of experiments, short exposure (30 min) of plants collected from 2.5 m confirmed that inhibition under PAR + UV-A was higher than under PAR + UV-A + UV-B. In general, full recovery after exposure to high solar irradiance (PAR + UVA + UV-B) occurred only in PAR-treated plants in September, Finally, when shoots of P. oceanica were preincubated for 4 d under PAR, PAR + UV-A or PAR + UV-A + UV-B and then submitted to full solar irradiance at the water surface, the greatest reduction in DeltaF/F-m' was seen in plants grown under PAR, while the lowest occurred in PAR + UV-A + UV-B pretreated plants in both seasons, Recovery was higher in PAR + UV-A + UV-B pretreated plants. UV solar irradiance also affected both maximal electron transport rate (ETR) and the initial slope of the ETR-irradiance curves. P. oceanica seems to be well acclimated to high solar irradiance, showing a high capacity for recovery. Solar UV-B might be involved in the impairment and recovery of photosynthesis, since removal of UV-B promoted higher inhibition by solar irradiance. The absence of UV under high PAR for several days resulted in a partial loss of the capacity for photoprotection. We conclude that UV radiation could act in the natural habitat as a trigger for the induction of photoprotective mechanisms against high solar irradiance. The ecological implication of the beneficial role of UV-B in well-acclimated marine plants to high irradiance is discussed. [References: 61] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Aquatic Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Figueroa FL Univ Malaga, Fac Ciencias, Dept Ecol Campus Univ de Teatinos S-N E-29071 Malaga Spain Univ Malaga, Fac Ciencias, Dept Ecol E-29071 Malaga Spain Univ Malaga, Fac Ciencias, Dept Biol Vegetal E-29071 Malaga Spain Univ Erlangen Nurnberg, Inst Bot & Pharmazeut Biol D-91058 Erlangen Germany <15> UI - 552VP-0016 DD - ISI Document Solution: 552VP AU - Kurata H AU - Azuma R AU - Nakabayashi K AU - Shimokawa K AU - Adachi M RA - Shimokawa K TI - Water soluble fluorescent substances in Citrus unshiu fruit and their possible participation in chlorophyll catabolism SO - Journal of the Japanese Society for Horticultural Science. 71(3):391-393, 2002 May. AS - J. Jpn. Soc. Hortic. Sci 2002 May;71(3):391-393 PU - JAPAN SOC HORTICULTURAL SCI, KYOTO UNIV, FACULTY AGRICULTURE, SAKYOKU, KYOTO, JAPAN IS - 0013-7626 MH - Chlorophyll catabolism MH - Citrus unshiu MH - Ethylene MH - Fluorescence substances. MH - In-vitro MH - Accumulation. AB - Changes in levels of fluorescence substances (FS) in aqueous extracts of Citrus unshiu (C. unshiu) peels were measured by the 3 -dimensional (3 - D) fluorescence spectrophotometer. FS, extracted from C. unshiu peels, have characteristic fluorescence at excitation (Ex) 320 - 330 nm and emission (Em) 420- 440 nm. Ex and Ern of FS are very similar to those of lipofucsin - like - compounds known to accumulate in tissues during aging and fluorescent -chlorophyll -catabolites (FCC) appeared to be a product of oxidative cleavage of chlorophyll (Chl)-porphyrin. The amount of FS increased in yellow -green C. unshiu peels and decreased in yellow C. unshiu peels. In ethylene- treated C. unshiu peels, the amount of ITS increased at the time of rapid disappearance of Chl, and decreased after that, whereas FS of non - treated C. unshiu peels did not change during incubation. A possible participation of FS in Chl catabolism is discussed. [References: 9] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Plant Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Shimokawa K Miyazaki Univ, Fac Agr Miyazaki 8892192 Japan Miyazaki Univ, Fac Agr Miyazaki 8892192 Japan Miyazaki Univ, Fac Educ & Culture Miyazaki 8892192 Japan <16> UI - 552YU-0033 DD - ISI Document Solution: 552YU AU - Jeuken LJC AU - Jones AK AU - Chapman SK AU - Cecchini G AU - Armstrong FA MA - Fraser.Armstrong@chem.ox.ac.uk RA - Armstrong FA TI - Electron-transfer mechanisms through biological redox chains in multicenter enzymes SO - Journal of the American Chemical Society. 124(20):5702-5713, 2002 May 22. AS - J. Am. Chem. Soc 2002 May 22;124(20):5702-5713 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 0002-7863 MH - Zinc cytochrome-c MH - Photosynthetic reaction-center MH - Self-assembled monolayers MH - Protein-film voltammetry MH - Coli fumarate reductase MH - Square-wave voltammetry MH - Blue copper protein MH - Crystal-structure MH - Charge-transfer MH - Shewanella-putrefaciens. AB - A new approach for studying intramolecular electron transfer in multicenter enzymes is described. Two fumarate reductases, adsorbed on an electrode in a fully active state, have been studied using square-wave voltammetry as a kinetic method to probe the mechanism of the long-range electron transfer to and from the buried active site. Flavocytochrome c(3) (Fcc(3)), the globular fumarate reductase from Shewanella frigidimarina, and the soluble subcomplex of the membrane-bound fumarate reductase of Escherichia coli (FrdAB) each contain an active site FAD that is redox-connected to the surface by a chain of hemes or Fe-S clusters, respectively. Using square-wave voltammetry with large amplitudes, we have measured the electron-transfer kinetics of the FAD cofactor as a function of overpotential. The results were modeled in terms of the FAD group receiving or donating electrons either via a direct mechanism or one involving hopping via the redox chain. The FrdAB kinetics could be described by both models, while the Fcc(3) data could only be fit on the basis of a direct electron-transfer mechanism. This raises the likelihood that electron transfer can occur via a superexchange mechanism utilizing the heme groups to enhance electronic coupling. Finally, the FrdAB data show, in contrast to Fcc3, that the maximum ET rate at high overpotential is related to the turnover number for FrdAB measured previously so that electron transfer is the limiting step during catalysis. [References: 60] 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 - 2002 week 24 IN - Reprint available from: Armstrong FA Univ Oxford, Inorgan Chem Lab S Parks Rd Oxford OX1 3QR England Univ Oxford, Inorgan Chem Lab Oxford OX1 3QR England Univ Edinburgh, Dept Chem Edinburgh EH9 3JJ Midlothian Scotland Univ Calif San Francisco, Div Mol Biol, DVA Med Ctr San Francisco, CA 94121 USA Univ Calif San Francisco, Dept Biochem & Biophys San Francisco, CA 94121 USA <17> UI - 553YY-0006 DD - ISI Document Solution: 553YY AU - Bergo E AU - Pursiheimo S AU - Paakkarinen V AU - Giacometti GM AU - Donella-Deana A AU - Andreucci F AU - Barbato R AU - Aro EM MA - roberto.barbato@unipm.it RA - Barbato R TI - Rapid and highly specific monitoring of reversible thylakoid protein phosphorylation by polyclonal antibody to phosphothreonine-containing proteins SO - Journal of Plant Physiology. 159(4):371-377, 2002 Apr. AS - J. Plant Physiol 2002 Apr;159(4):371-377 PU - URBAN & FISCHER VERLAG, BRANCH OFFICE JENA, P O BOX 100537, D-07705 JENA, GERMANY. URL: http://www.urbanfischer.de IS - 0176-1617 MH - Cucurbita pepo MH - Hordeum vulgare MH - Photosystem ii MH - Secale cereale MH - Thylakoid phosphoproteins. MH - Ii reaction-center MH - Harvesting complex-ii MH - Photosystem-ii MH - Subunit cp29 MH - Light MH - Membranes MH - Chloroplasts MH - Phosphoproteins MH - Polypeptides MH - Plastoquinol. AB - Reversible thylakoid protein phosphorylation in plant chloroplast probably plays an important role in acclimation of the photosynthetic apparatus to changes in environmental conditions. Studies of regulation and the significance of these reactions have in vivo greatly benefited from recent availability of phosphothreonine antibodies. To verify the specificity of these polyclonal antibodies, leaves were treated in conditions expected to induce either phosphorylation or dephosphorylation of thylakoid proteins D1, D2 and CP43 of the photosystem 11 core as well as light harvesting polypeptides of 27 and 25 kDa; subsequently, the proteins were isolated to homogeneity. Immunoreactions of these purified proteins with phosphothreonine antibodies were very similar to those observed with intact thylakoids. Moreover, their positive immunoresponse could be totally abolished by treating the thylakoid samples or purified photosystem 11 core preparations with acid phosphatase before immunoblotting. We conclude that the analytical method of using polyclonal phosphothreonine antibodies will turn out to be a highly specific and valuable tool in monitoring changes in the phosphorylation patterns of individual thylakoid phosphoproteins, both in vivo and in vitro. [References: 33] 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 - 2002 week 24 IN - Reprint available from: Barbato R Univ Piemonte Orientale Amedeo Avogadro, Dipartimento Sci & Tecnol Avanzate Corso Borsalino 54 I-15100 Alessandria Italy Univ Piemonte Orientale Amedeo Avogadro, Dipartimento Sci & Tecnol Avanzate I-15100 Alessandria Italy Univ Padua, CNR, Dipartimento Chim Biol I-35131 Padua Italy Univ Padua, CNR, Ctr Studio Biomembrane I-35131 Padua Italy Univ Turku, Dept Biol FIN-20014 Turku Finland Univ Padua, Dipartimento Biol I-35131 Padua Italy <18> UI - 552CR-0008 DD - ISI Document Solution: 552CR AU - D'Souza F AU - Deviprasad GR AU - Zandler ME AU - El-Khouly ME AU - Fujitsuka M AU - Ito O RA - D'Souza F TI - Electronic interactions and photoinduced electron transfer in covalently linked porphyrin-C-60(pyridine) diads and supramolecular triads formed by self-assembling the diads and zinc porphyrin SO - Journal of Physical Chemistry B. 106(19):4952-4962, 2002 May 16. AS - J. Phys. Chem. B 2002 May 16;106(19):4952-4962 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 1089-5647 MH - Laser flash-photolysis MH - Charge separation MH - Artificial photosynthesis MH - Fullerene dyad MH - Photophysical properties MH - Cyclic voltammetry MH - Solvent dependence MH - Tail-on MH - Systems MH - C-60. AB - Supramolecular triads of the type (donor-1)-acceptor:(donor-2) composed of free-base porphyrin, fullerene, and zinc porphyrin, have been formed by a "covalent-coordinate" approach. Toward this, two diads, namely, 5-(3'-(2"-(3'" or 4"'-pyridyl)fulleropyrrolidinyl-N)ethoxyphenyl)-10,15,20-triphenylpo rphyrin, bewing C-60 as acceptor and free-base porphyrin, H2P, as donor were first synthesized. The diads and self-assembled supramolecular triads, which were formed by coordinating the pyridine group located on the diads to zinc tetraphenylporphyrin, ZnP, have been characterized by semiempirical PM3, electrochemistry, and steady-state and time-revolved spectroscopic techniques. Subpicosecond and nanosecond transient absorption spectral studies of diads revealed the occurrence of the electron transfer from the H2P Moiety to the C-60 entity via the excited singlet state of H2P. Clear evidence for the formation of triads in o-dichlorobenzene was obtained from the steady-state and time-resolved fluorescence measurements, which revealed quenching of the ZnP emission on addition of the pyridine bearing diads. Semiempirical PM3 energy optimized structures of the triads suggested substantial intramolecular interactions between the H2P and C-60 entities. Cyclic voltammetric studies on these triads exhibited a total of 12 one-electron redox processes involving the three redox active ZnP, H2P, and C60 entities. Nanosecond transient absorption studies revealed additional charge separation in the triads as compared to that observed for the diads, suggesting that the coordinated ZnP accelerates the charge-separation process. However, in a coordinating solvent such as benzonitrile, intermolecular electron transfer from the (ZnP)-Zn-3* to the diads is shown to take place. [References: 73] 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 - 2002 week 24 IN - Reprint available from: D'Souza F Wichita State Univ, Dept Chem 1845 Fairmount Wichita, KS 67260 USA Wichita State Univ, Dept Chem Wichita, KS 67260 USA Tohoku Univ, Inst Multidisciplinary Res Adv Mat Sendai Miyagi 9808577 Japan <19> UI - 552UW-0019 DD - ISI Document Solution: 552UW AU - Sinnecker S AU - Koch W AU - Lubitz W RA - Koch W TI - Chlorophyll a radical ions: A density functional study SO - Journal of Physical Chemistry B. 106(20):5281-5288, 2002 May 23. AS - J. Phys. Chem. B 2002 May 23;106(20):5281-5288 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 1089-5647 MH - Photosynthetic reaction centers MH - Hyperfine coupling-constants MH - Primary electron-donor MH - Triple-resonance MH - Photosystem-i MH - Cation radicals MH - Plant photosynthesis MH - Single-crystals MH - Anion-radicals MH - Endor. AB - The chlorophyll a radical cation, Chl a(+.), and the corresponding radical anion, Chl a(-.), have been investigated applying density functional methods. Furthermore, the C-10 epimer Chl a' and O-1 Chl a enol radical cations have been studied, which have been proposed to play a role in photosystem I of oxygenic photosynthesis. Isotropic hyperfine coupling constants (hfcs) and related spin density distributions calculated at the B3LYP/EPR-II//BLYP/DZVP(D) level of theory are reported. For Chl a(+.) and Chl a(-.), good agreement is observed between calculated and experimental hfes. Whereas no larger differences in the hfcs between Chl a(+.) and (Chl a')(+.) are predicted to occur, the enol forms of Chl a(+.) give rise to significantly altered hyperfine coupling constants in comparison with the respective keto form. In addition to the chlorophyll systems, the epimer and 01 enol of bacteriochlorophyll a have also been calculated. From a comparison with experimental data it is concluded that the enol forms do not occur in photosynthetic reaction centers. [References: 54] 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 - 2002 week 24 IN - Reprint available from: Koch W Max Planck Inst Strahlenchem Postfach 101365 D-45413 Mulheim Germany Max Planck Inst Strahlenchem D-45413 Mulheim Germany Tech Univ Berlin, Inst Chem D-10623 Berlin Germany Tech Univ Berlin, Max Volmer Lab Biophys Chem D-10623 Berlin Germany <20> UI - 552CQ-0004 DD - ISI Document Solution: 552CQ AU - Josue JS AU - Frank HA MA - harry.frank@uconn.edu RA - Frank HA TI - Direct determination of the S-1 excited-state energies of xanthophylls by low-temperature fluorescence spectroscopy SO - Journal of Physical Chemistry. 106(19):4815-4824, 2002 May 16. AS - J. Phys. Chem. A 2002 May 16;106(19):4815-4824 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 1089-5639 MH - Light-harvesting complexes MH - Resolution optical spectroscopy MH - Photosystem-ii MH - Higher-plants MH - Carotenoid spheroidene MH - Electronic states MH - Long polyenes MH - Green plants MH - One-photon MH - Gap law. AB - The xanthophylls, violaxanthin, lutein, and zeaxanthin, associated with the antenna protein assembly of Photosystem II (PS II) play roles as light-harvesting pigments and protective agents in the photosynthetic apparatus of higher plants. The dissipation of excitation energy exceeding that needed for photosynthesis is thought to be regulated by an enzymatic process known as the xanthophyll cycle where violaxanthin and zeaxanthin are reversibly interconverted, but the role of the cycle in controlling the process in vivo is not clear. The two hypotheses are (i) direct quenching of chlorophyll excited states by the xanthophylls and (ii) indirect quenching via carotenoid-mediated changes in the structure of the light-harvesting complexes. These mechanisms depend on the structures and/or energetics of the xanthophyll pigments, which have not yet been fully elucidated. In this work, fluorescence spectroscopy at 77 K has been used to determine the energies of the S-1 excited states of violaxanthin, zeaxanthin, and the major xanthophyll component of green plants, lutein. High performance liquid chromatography (HPLC) was carried out just prior to the spectroscopic experiments to obtain isomerically pure samples devoid of fluorescent contaminants. The experiments at cryogenic temperatures provide enhanced resolution compared to room-temperature studies, reveal clearly the vibronic features of the fluorescence line shapes, and allow precise, direct assignments of the spectral origins and electronic-state energies of the molecules. The results are important for broadening our understanding of the mechanisms of light-harvesting and nonphotochemical dissipation of excess energy in plants. [References: 64] 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 - 2002 week 24 IN - Reprint available from: Frank HA Univ Connecticut, Dept Chem U-3060,55 N Eagleville Rd Storrs, CT 06269 USA Univ Connecticut, Dept Chem Storrs, CT 06269 USA <21> UI - 552UU-0010 DD - ISI Document Solution: 552UU AU - Fukuzumi S AU - Ohkubo K AU - Chen YH AU - Pandey RK AU - Zhan RQ AU - Shao JG AU - Kadish KM MA - fukuzumi@ap.chem.eng.osaka-u.ac.jp, Ravindra.Pandey@RoswellPark.org, KKadish@uh.edu RA - Fukuzumi S TI - Photophysical and electrochemical properties of new bacteriochlorins and characterization of radical cation and radical anion species SO - Journal of Physical Chemistry. 106(20):5105-5113, 2002 May 23. AS - J. Phys. Chem. A 2002 May 23;106(20):5105-5113 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 1089-5639 MH - Electron-transfer MH - Photodynamic therapy MH - Reaction centers MH - Model compounds MH - Chlorophyll-a MH - Chlorin MH - Porphyrin MH - Series MH - Epr MH - Photosensitization. AB - The synthesis, photophysical, and photochemical properties of a series of stable bacteriochlorins containing a fused six-member anhydride or an imide ring are discussed. The Q(y) band (a(1u) --> e(gx) transition) in the near-infrared region (NIR) lies between 788 and 831 nm depending upon the macrocycle substituents. Compounds with such a long-wavelenth absorption are highly promising for their potential use in photodynamic therapy. Fluorescence maxima are also observed in the long-wavelength region of the spectrum, between 804 and 842 nm, and have lifetimes between 1.1 and 1.4 ns. The phosphorescence maxima are red-shifted to 840-870 nm. The triplet-triplet transient absorption spectra are observed to have maxima between 570 and 640 nm with lifetimes between 72 and 150 mus. The triplet excited states are efficiently quenched by oxygen to produce singlet oxygen. The quantum yields of the generated singlet oxygen were determined to be in the range of 0.33-0.55. The bacteriochlorin derivatives are easy to oxidize by one electron, and reversible half-wave potentials range between 0.65 and 0.82 V vs SCE in benzonitrile containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). The second oxidation is irreversible and occurs at a rather constant potential of 1.17-1.22 V independent of the macrocycle substituents. The bacteriochlorin derivatives are also easy to reduce, and the reversible first and second one-electron reduction potentials range between -0.53 and -0.80 V and between -0.95 and -1.28 V vs SCE, respectively. Spectroelectrochemical measurements reveal the expected pi radical cation and pi radical anion marker bands of the bacteriochlorin derivatives. The electron spin resonance (ESR) spectra of the radical cations and radical anions produced by the chemical oxidation and reduction are reported, and the experimental and calculated spin densities are compared to each other. [References: 48] 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 - 2002 week 24 IN - Reprint available from: Fukuzumi S Osaka Univ, CREST, Japan Sci & Technol Corp,JST, Dept Mat & Life Sci,Grad Sch Engn 2-1 Yamadaoka Suita Osaka 5650871 Japan Osaka Univ, CREST, Japan Sci & Technol Corp,JST, Dept Mat & Life Sci,Grad Sch Engn Suita Osaka 5650871 Japan Roswell Pk Canc Inst, Photodynam Therapy Ctr, Div Chem Buffalo, NY 14263 USA Roswell Pk Canc Inst, Dept Nucl Med Buffalo, NY 14263 USA Univ Houston, Dept Chem Houston, TX 77204 USA <22> UI - 553AQ-0004 DD - ISI Document Solution: 553AQ AU - Ralph PJ AU - Polk SM AU - Moore KA AU - Orth RJ AU - Smith WO MA - Peter.Ralph@uts.edu.au RA - Ralph PJ TI - Operation of the xanthophyll cycle in the seagrass Zostera marina in response to variable irradiance SO - Journal of Experimental Marine Biology & Ecology. 271(2):189-207, 2002 May 24. AS - J. Exp. Mar. Biol. Ecol 2002 May 24;271(2):189-207 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0022-0981 MH - Carotenoids MH - Xanthophyll MH - Non-photochemical quenching MH - Chlorophyll-a fluorescence MH - Light stress. MH - Photosystem-ii MH - High light MH - Pigments MH - Fluorescence MH - Stress MH - Leaves MH - Photoinhibition MH - Dissipation MH - Efficiency MH - Sunlight. AB - Changes in the photobiology and photosynthetic pigments of the seagrass Zostera marina from Chesapeake Bay (USA) were examined under a range of natural and manipulated irradiance regimes. Photosynthetic activity was assessed using chlorophyll-a fluorescence, and photosynthetic pigments were measured by HPLC. Large changes in the violaxanthin, zeaxanthin, and antheraxanthin content were concomitant with the modulation of non-photochemical quenching (NPQ). Photokinetics (F-v/F-m rapid light curves (RLC), and non-photochemical quenching) varied as a result of oscillating irradiance and were highly correlated to xanthophyll pigment content. Zeaxanthin and antheraxanthin concentrations increased under elevated light conditions, while violaxanthin increased in darkened conditions. Unusually high concentrations of antheraxanthin were found in Z. marina under a wide range of light conditions, and this was associated with the partial conversion of violaxanthin to zeaxanthin. These results support the idea that xanthophyll intermediate pigments induce a photoprotective response during exposure to high irradiances in this seagrass. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 27] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Aquatic Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Ralph PJ Univ Technol Sydney, Inst Coastal Resource Management, Dept Envir Biol & Hort Westbourne St,Gore Hill Sydney NSW 2065 Australia Univ Technol Sydney, Inst Water & Environm Resource Management St Leonards NSW 2065 Australia Coll William & Mary, Virginia Inst Marine Sci, Sch Marine Sci Williamsburg, VA 23602 USA <23> UI - 553UJ-0004 DD - ISI Document Solution: 553UJ AU - Fryer MJ AU - Oxborough K AU - Mullineaux PM AU - Baker NR MA - baken@essex.ac.uk RA - Baker NR TI - Imaging of photo-oxidative stress responses in leaves SO - Journal of Experimental Botany. 53(372):1249-1254, 2002 May. AS - J. Exp. Bot 2002 May;53(372):1249-1254 PU - OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND. URL: http://www.oup.co.uk IS - 0022-0957 MH - Ascorbate peroxidase MH - Chlorophyll fluorescence MH - Hydrogen peroxide MH - Singlet oxygen MH - Superoxide. MH - Singlet oxygen MH - Intact leaves MH - Photoinhibition MH - Superoxide MH - Plants MH - Antioxidants MH - Maize MH - Photosynthesis MH - Localization MH - Fluorescence. AB - High resolution digital imaging was used to identify sites of photo-oxidative stress responses in Arabidopsis leaves non-invasively, and to demonstrate the potential of using a suite of imaging techniques for the study of oxidative metabolism in planta. Tissue-specific photoinhibition of photosynthesis in individual chloroplasts in leaves was imaged by chlorophyll fluorescence microscopy. Singlet oxygen production was assessed by imaging the quenching of the fluorescence of dansyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole (DanePy) that results from its reaction with singlet oxygen. Superoxide and hydrogen peroxide accumulation were visualized by the reduction of nitroblue tetrazolium (NBT) to formazan deposits and by polymerization with 3,3'-diaminobenzidine (DAB), respectively. Stress-induced expression of a gene involved with antioxidant metabolism was imaged from the bioluminescence from leaves of an Arabidopsis APX2-LUC transformant, which co-expresses an ascorbate peroxidase (APX2) with firefly luciferase. Singlet oxygen and superoxide production were found to be primarily located in mesophyll tissues whereas hydrogen peroxide accumulation and APX2 gene expression were primarily localized in the vascular tissues. [References: 26] 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 - 2002 week 24 IN - Reprint available from: Baker NR Univ Essex, Dept Biol Sci Colchester CO4 3SQ Essex England Univ Essex, Dept Biol Sci Colchester CO4 3SQ Essex England John Innes Ctr Plant Sci Res Norwich NR4 7UH Norfolk England <24> UI - 553PR-0053 DD - ISI Document Solution: 553PR AU - Bottcher B AU - Scheide D AU - Hesterberg M AU - Nagel-Steger L AU - Friedrich T MA - tfriedri@uni-freiburg.de RA - Friedrich T TI - A novel, enzymatically active conformation of the Escherichia coli NADH : ubiquinone oxidoreductase (complex I) SO - Journal of Biological Chemistry. 277(20):17970-17977, 2002 May 17. AS - J. Biol. Chem 2002 May 17;277(20):17970-17977 PU - AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA. URL: http://www.asbmb.org IS - 0021-9258 MH - Proton-translocating nadh MH - Mitochondrial nadh MH - 3-dimensional structure MH - Neurospora-crassa MH - Electron-microscopy MH - Respiratory nadh MH - Membrane MH - Dehydrogenase MH - Subunit MH - Transition. AB - Electron microscopy has demonstrated the unusual L-shaped structure of the respiratory complex I consisting of two arms, which are arranged perpendicular to each other. We found that the Escherichia coli complex I has an additional stable conformation, with the two arms arranged side by side, resulting in a horseshoe-shaped structure. The structure of both conformations was determined by means of electron microscopy of gold thioglucose-stained single particles. They were distinguished from each other by titration of the complex with polyethylene glycol and by means of analytical ultracentrifugation. The transition between the two conformations is induced by the ionic strength of the buffer and is reversible. Only the horseshoe-shaped complex I exhibits enzyme activity in detergent solution, which is abolished by the addition of salt. Therefore, it is proposed that this structure is the native conformation of the complex in the membrane. [References: 41] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Friedrich T Univ Freiburg, Inst Org Chem & Biochem Albertstr 21 D-79104 Freiburg Germany European Mol Biol Lab, Struct Biol & Biocomp Programme D-69117 Heidelberg Germany Univ Dusseldorf, Inst Phys Biol D-40225 Dusseldorf Germany <25> UI - 552AP-0005 DD - ISI Document Solution: 552AP AU - Lux R AU - Sim JH AU - Tsai JP AU - Shi W MA - wenyuan@ucla.edu RA - Shi W TI - Construction and characterization of a cheA mutant of Treponema denticola SO - Journal of Bacteriology. 184(11):3130-3134, 2002 Jun. AS - J. Bacteriol 2002 Jun;184(11):3130-3134 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Oral spirochete MH - Borrelia-burgdorferi MH - Escherichia-coli MH - Intestinal-mucosa MH - Insertional inactivation MH - Rhodobacter-sphaeroides MH - Signal-transduction MH - Chemotaxis operon MH - Filamentous cells MH - Motile bacteria. AB - The Treponema denticola cheA gene, encoding the central kinase of the general chemotaxis pathway, was analyzed for its role in chemotaxis and tissue penetration. The cheA gene was interrupted by insertion of an ermF-ermAM gene cassette. Reverse transcription-PCR confirmed that the other downstream chemotaxis genes within the same operon (cheW, cheX, and cheY were still expressed in the cheA mutant strain. Lack of cheA resulted in decreased swarming on soft-agar swarm plates and failure to respond chemotactically to a mixture of nutrients. Behavioral analyses using video microscopy revealed that the cheA mutant exhibited coordinated cell movement. The cellular reversal frequency, however, was severely reduced, indicating that CheA in T. denticola mainly controls cellular reversal and that active chemotaxis signaling input is not required for coordination of flagellar rotation at both cell poles. [References: 51] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Shi W Univ Calif Los Angeles, Sch Dent Los Angeles, CA 90095 USA Univ Calif Los Angeles, Sch Dent Los Angeles, CA 90095 USA Univ Calif Los Angeles, Inst Mol Biol Los Angeles, CA 90095 USA <26> UI - 552AP-0029 DD - ISI Document Solution: 552AP AU - Anjum MF AU - Stevanin TM AU - Read RC AU - Moir JWB MA - T.Stevanin@sheffield.ac.uk RA - Stevanin TM TI - Nitric oxide metabolism in Neisseria meningitidis SO - Journal of Bacteriology. 184(11):2987-2993, 2002 Jun. AS - J. Bacteriol 2002 Jun;184(11):2987-2993 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Anaerobic growth MH - Paracoccus-denitrificans MH - Rhodobacter-capsulatus MH - S-nitrosothiols MH - Cytochrome c' MH - Gonorrhoeae MH - Gene MH - Reductase MH - Macrophages MH - Mutagenesis. AB - Neisseria meningitidis, the causative agent of meningococcal disease in humans, is likely to be exposed to nitrosative stress during natural colonization and disease. The genome of N. meningitidis includes the genes aniA and norB, predicted to encode nitrite reductase and nitric oxide (NO) reductase, respectively. These gene products should allow the bacterium to denitrify nitrite to nitrous oxide. We show that N. meningitidis can support growth microaerobically by the denitrification of nitrite via NO and that norB is required for anaerobic growth with nitrite. NorB and, to a lesser extent, the cycP gene product cytochrome c' are able to counteract toxicity due to exogenously added NO. Expression of these genes by N. meningitidis during colonization and disease may confer protection against exogenous or endogenous nitrosative stress. [References: 35] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Stevanin TM Univ Sheffield, Sch Med, Div Genom Med Beech Hill Rd Sheffield S10 2RX S Yorkshire England Univ Sheffield, Sch Med, Div Genom Med Sheffield S10 2RX S Yorkshire England Univ Sheffield, Dept Mol Biol & Biotechnol Sheffield S10 2TN S Yorkshire England <27> UI - 552AP-0032 DD - ISI Document Solution: 552AP AU - Stingl K AU - Uhlemann EM AU - Schmid R AU - Altendorf K AU - Bakker EP MA - stingl@biologie.uni-osnabrueck.de RA - Stingl K TI - Energetics of Helicobacter pylori and its implications for the mechanism of urease-dependent acid tolerance at pH 1 SO - Journal of Bacteriology. 184(11):3053-3060, 2002 Jun. AS - J. Bacteriol 2002 Jun;184(11):3053-3060 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Proton-motive force MH - Acidophilic bacteria MH - Cytoplasmic urease MH - Membrane MH - Homeostasis MH - Resistance MH - Acidocaldarius MH - Bioenergetics MH - Difference MH - Transport. AB - In the presence of urea the neutrophilic human pathogen Helicobacterpylori survives for several hours at pH I with concomitant cytoplasmic pH homeostasis. To study this effect in detail, the transmembrane proton motive force and cytoplasmic urease activity of H. pylori were determined at various pH values. In the absence of urea, the organism maintained a close-to-neutral cytoplasm and an internally negative membrane potential at external pH values greater than 4 to 5. In the presence of urea, H. pylori accomplished cytoplasmic pH homeostasis down to an external pH of 1.2. At this external pH, the cytoplasmic pH was 4.9 and the membrane potential was slightly negative inside. The latter finding is in contrast to the situation in acidophiles, which develop inside-positive membrane potentials under similar conditions. Measurements of the time course of the membrane potential confirmed that addition of urea to the cells led to hyperpolarization. Most likely, this effect was due to electrogenic export of ammonium cations from the cytoplasm. The urease activity of intact cells increased nearly exponentially with decreasing external pH. This activation was not due to enhanced gene expression at low external pH values. In cell extracts the pH optimum of urease activity was dependent on the buffer system and was about pH 5 in sodium citrate buffer. Since this is the cytoplasmic pH of the cells at pH I to 2, we propose that cytoplasmic pH is a factor in the in vivo activation of the urease at low external pH values. The mechanism by which urease activity leads to cytoplasmic pH homeostasis in H. pylori is discussed. [References: 39] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Stingl K Univ Osnabruck, Abt Mikrobiol D-49069 Osnabruck Germany Univ Osnabruck, Abt Mikrobiol D-49069 Osnabruck Germany <28> UI - 552AP-0033 DD - ISI Document Solution: 552AP AU - Grammann K AU - Volke A AU - Kunte HJ MA - kunte@uni-bonn.de RA - Kunte HJ TI - New type of osmoregulated solute transporter identified in halophilic members of the Bacteria domain: TRAP transporter TeaABC mediates uptake of ectoine and hydroxyectoine in Halomonas elongata DSM 2581(T) SO - Journal of Bacteriology. 184(11):3078-3085, 2002 Jun. AS - J. Bacteriol 2002 Jun;184(11):3078-3085 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Gram-negative bacteria MH - Escherichia-coli k-12 MH - Compatible solutes MH - Glycine betaine MH - Ectothiorhodospira-halochloris MH - Corynebacterium-glutamicum MH - Rhodobacter-capsulatus MH - Protein MH - Mutagenesis MH - Sequence. AB - The halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. We constructed a deletion mutant of H. elongata, KB1, defective in ectoine synthesis and tolerating elevated salt concentrations only in the presence of external compatible solutes. The dependency of KB1 on solute uptake for growth in high-salt medium was exploited to select insertion mutants unable to accumulate external solutes via osmoregulated transporters. One insertion mutant out of 7,200 failed to accumulate the osmoprotectants ectoine and hydroxyectoine. Genetic analysis of the insertion site proved that the mutation affected an open reading frame (ORF) of 1,281 bp (teaC). The nucleotide sequence upstream of teaC was determined, and two further ORFs of 603 bp (teaB) and 1,023 bp (tea,4) were identified. Deletion of teaA and teaB proved that all three genes are mandatory for ectoine uptake. Sequence comparison showed significant identity of TeaA, TeaB, and TeaC to the transport proteins of the recently identified tripartite ATP-independent periplasmic transporter family (TRAP-T). The affinity of the cells for ectoines was determined (K-s = 21.7 muM), suggesting that the transporter TeaABC exhibits high affinity for ectoines. An elevation of the external osmolarity resulted in a strong increase in ectoine uptake via TeaABC, demonstrating that this transporter is osmoregulated. Deletion of teaC and teaBC in the wild-type strain led to mutants which excreted significant amounts of ectoine into the medium when cultivated at high salt concentrations. Therefore, the physiological role of TeaABC may be primarily to recover ectoine leaking through the cytoplasmic membrane. [References: 57] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Kunte HJ Univ Bonn, Inst Mikrobiol & Biotechnol Meckenheimer Allee 168 D-53115 Bonn Germany Univ Bonn, Inst Mikrobiol & Biotechnol D-53115 Bonn Germany <29> UI - 552AP-0037 DD - ISI Document Solution: 552AP AU - Sluis MK AU - Larsen RA AU - Krum JG AU - Anderson R AU - Metcalf WW AU - Ensign SA MA - ensigns@cc.usu.edu RA - Ensign SA TI - Biochemical, molecular, and genetic analyses of the acetone carboxylases from Xanthobacter autotrophicus strain Py2 and Rhodobacter capsulatus strain B10 SO - Journal of Bacteriology. 184(11):2969-2977, 2002 Jun. AS - J. Bacteriol 2002 Jun;184(11):2969-2977 PU - AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA. URL: http://www.asmusa.org IS - 0021-9193 MH - Pathogen helicobacter-pylori MH - Sulfate-reducing bacterium MH - D-hydantoinase gene MH - Denitrifying bacteria MH - Microbial-metabolism MH - Cytochrome-p450 2e1 MH - Pseudomonas-putida MH - Catabolic pathway MH - Bacillus-subtilis MH - Escherichia-coli. AB - Acetone carboxylase is the key enzyme of bacterial acetone metabolism, catalyzing the condensation of acetone and CO2 to form acetoacetate. In this study, the acetone carboxylase of the purple nonsulfur photosynthetic bacterium Rhodobacter capsulatus was purified to homogeneity and compared to that of Xanthobacter autotrophicus strain Py2, the only other organism from which an acetone carboxylase has been purified. The biochemical properties of the enzymes were virtually indistinguishable, with identical subunit compositions (alpha(2)beta(2)gamma(2) multimers of 85-, 78-, and 20-kDa subunits), reaction stoichiometries (CH3COCH3 + CO2 + ATP-->CH3COCH2COO- + H+ + AMP + 2P(i)), and kinetic properties (K-m for acetone, 8 muM; k(cat) = 45 min(-1)). Both enzymes were expressed to high levels (17 to 25% of soluble protein) in cells grown with acetone as the carbon source but were not present at detectable levels in cells grown with other carbon sources. The genes encoding the acetone carboxylase subunits were identified by transposon mutagenesis of X. autotrophicus and sequence analysis of the R. capsulatus genome and were found to be clustered in similar operons consisting of the genes acxA (beta subunit), acxB (alpha subunit), and acxC (gamma subunit). Transposon mutagenesis of X. autotrophicus revealed a requirement of sigma(54) and a sigma(54)-dependent transcriptional activator (AcxR) for acetone-dependent growth and acetone carboxylase gene expression. A potential sigma(54)-dependent promoter 122 bp upstream of X. autotrophicus acxABC was identified. An AcxR gene homolog was identified 127 bp upstream of acxA in R. capsulatus, but this activator lacked key features of sigma(54)-dependent activators, and the associated acxABC lacked an apparent sigma(54)-dependent promoter, suggesting that sigma(54) is not required for expression of acxABC in R. capsulatus. These studies reveal a conserved strategy of ATP-dependent acetone carboxylation and the involvement of transcriptional enhancers in acetone carboxylase gene expression in gram-negative acetone-utilizing bacteria. [References: 52] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Ensign SA Utah State Univ, Dept Chem & Biochem Logan, UT 84322 USA Utah State Univ, Dept Chem & Biochem Logan, UT 84322 USA Univ Illinois, Dept Microbiol Urbana, IL 61801 USA <30> UI - 553MY-0009 DD - ISI Document Solution: 553MY AU - Levy SB MA - stuart.levy@tufts.edu RA - Levy SB TI - Active efflux, a common mechanism for biocide and antibiotic resistance SO - Journal of Applied Microbiology. 92(Suppl 1):65S-71S, 2002. AS - J. Appl. Microbiol 2002;92(Suppl 1):65S-71S PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 1364-5072 MH - Hybrid tet proteins MH - Escherichia-coli MH - Tetracycline resistance MH - Mar mutants MH - Gene MH - Determinants MH - Mutations MH - Locus MH - Tn10 MH - Complementation. AB - Energy-driven drug efflux systems are increasingly recognized as mechanisms of antibiotic resistance. Chromosomally located or acquired by bacteria, they can either be activated by environmental signals or by a mutation in a regulatory gene. Two major categories exist: those systems energized by proton motive force and those dependent on ATP. The pumps may have limited or broad substrates, the so-called multiple drug resistance pumps, which themselves form a number of related families. The multiple antibiotic resistance (mar) locus and mar regulon in Escherichia coli and other members of the Enterobacteriaceae is a paradigm for a generalized response locus leading to increased expression of efflux pumps. One such pump, the AcrAB pump extrudes biocides such as triclosan, chlorhexidine and quaternary ammonium compounds as well as multiple antibiotics. In Pseudomonas aeruginosa, a number of multidrug efflux pumps export a broad range of substrates. Since bacteria expressing these pumps thwart the efficacy of both kinds of therapeutic agents which control infectious diseases biocides which prevent transmission of infectious disease agents and antibiotics which treat and cure infectious diseases - they are of particular concern. The prudent use of antibiotics and biocides will guard against the selection and propagation of drug - resistant mutants and preserve the efficacy of these valuable anti-infective agents. [References: 42] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Biology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Levy SB Tufts Univ, Sch Med, Ctr Adaptat Genet & Drug Resistance Boston, MA 02111 USA Tufts Univ, Sch Med, Ctr Adaptat Genet & Drug Resistance Boston, MA 02111 USA Tufts Univ, Sch Med, Dept Mol Biol Boston, MA 02111 USA Tufts Univ, Sch Med, Dept Microbiol Boston, MA 02111 USA Tufts Univ, Sch Med, Dept Med Boston, MA 02111 USA <31> UI - 554AR-0006 DD - ISI Document Solution: 554AR AU - Suzuki K AU - Sami M AU - Kadokura H AU - Nakajima H AU - Kitamoto K MA - koji.suzuki@asahibeer.co.jp RA - Suzuki K TI - Biochemical characterization of horA-independent hop resistance mechanism in Lactobacillus brevis SO - International Journal of Food Microbiology. 76(3):223-230, 2002 Jun 25. AS - Int. J. Food Microbiol 2002 Jun 25;76(3):223-230 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0168-1605 MH - Hop resistance MH - Lactobacillus brevis MH - Multidrug resistance. MH - Lactic-acid bacteria MH - Multidrug-resistance MH - Trans-isohumulone MH - Escherichia-coli MH - Transporters MH - Systems MH - Ability MH - Locus MH - Beer MH - Gene. AB - We isolated a strain from hop-resistant Lactobacillus brevis ABBC45, which had lost a plasmid (pRH45) harboring a putative hop resistance gene, horA. The hop resistance level of this horA-deficient strain, named ABBC45(C), was initially low but gradually induced by repeated growth in media containing progressively increasing levels of hop compounds. Although the hop resistance level was substantially lower than that of the hop-adapted wild type strain, hop-adapted ABBC45(C) (ABBC45(CR)) was still capable of growing in beer, suggesting ABBC45 possesses at least two hop resistance mechanisms. Hop resistance acquired by ABBC45(CR) gradually diminished to the pre-adapted level, when the strain was grown repeatedly in the absence of hop compounds. ABBC45(CR) was found to be cross-resistant to several structurally unrelated drugs, including ethidium. bromide, daunomycin and nisin. In addition, ABBC45(CR) was shown to extrude ethidium in an energy-dependent manner, while ABBC45(C) did not show such activity. This indicates that the efflux pump was induced by adaptation to hop compounds. The efflux activity of ethidium was reduced by the addition of hop compounds, suggesting hop compounds are also the substrate of the efflux pump. It was also shown that the efflux activity was completely dissipated with the abolition of proton motive force (PMF). These results, taken together, suggest the hop resistance mechanism of ABBC45(C) is mediated by PMF-dependent multidrug efflux pump. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 23] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Food Science/Nutrition in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Suzuki K Asahi Brewery Co Ltd, Corp Prod Evaluat Ctr Midori 1-1-21 Moriya Ibaraki 3020106 Japan Asahi Brewery Co Ltd, Corp Prod Evaluat Ctr Moriya Ibaraki 3020106 Japan Asahi Brewery Co Ltd, Key Technol Res Lab Moriya Ibaraki 3020106 Japan Univ Tokyo, Dept Biotechnol, Bunkyo Ku Tokyo 1138567 Japan <32> UI - 553EX-0003 DD - ISI Document Solution: 553EX AU - Norris TB AU - McDermott TR AU - Castenholz RW MA - rcasten@darkwing.uoregon.edu RA - Castenholz RW TI - The long-term effects of UV exclusion on the microbial composition and photosynthetic competence of bacteria in hot-spring microbial mats SO - FEMS Microbiology Ecology. 39(3):193-209, 2002 Mar. AS - FEMS Microbiol. Ecol 2002 Mar;39(3):193-209 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0168-6496 MH - Ultraviolet radiation MH - Hot spring MH - Microbial mat MH - Cyanobacteria MH - Photosynthesis MH - Denaturing gradient gel electrophoresis. MH - 16s ribosomal-rna MH - Gradient gel-electrophoresis MH - Ultraviolet-b radiation MH - Visible irradiance MH - Cyanobacterial mat MH - Photosystem-ii MH - Synechococcus populations MH - Defined populations MH - Solar uv MH - Community. AB - The primary objective of this study was to determine whether the long-term exclusion of ultraviolet (UV) radiation (UVR) from hot-spring microbial mats resulted in an alteration of microbial composition. such as a shift to more UV-sensitive species, Over a 1-3-month period, microbial mats in two alkaline geothermal streams in Yellowstone National Park were covered with filters that excluded or transmitted UVR. Over some, 2511,, transmission neutral density screens were also used. In the 40-47degreesC range, there were no apparent changes in community composition during the summer with or without high or low UVR, as assessed by denaturing gradient gel electrophoresis (DGGE) profiles after polymerase chain reaction amplification of 16S-rRNA genes with general Bacteria and Cyanobacteria primers. Major bands were purified from the DGGE gels and sequenced. Only one of the cyanobacterial sequences matched known strains in the database: the others appear to be unique, Although the bacterial composition of these communities was apparently stable, surface layers of cyanobacteria protected from UVR were not as competent photosynthetically as those that had been maintained under UVR. This decrease in competence was expressed as a loss of the ability to perform at a maximum rate under full UVR plus visible irradiance. However, even +UV-maintained cyanobacteria performed better when UVR was excluded during the photosynthesis tests. It is probable that the large differences in photosynthetic competence observed reflect changes at the level of gene expression in the dominant species rather than changes in species composition. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved. [References: 45] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences CC - Biology in Current Contents(R)/Agricultural, Biology & Environmental Sciences. Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Castenholz RW Univ Oregon, Dept Biol, Ecol & Evolut Program Eugene, OR 97403 USA Univ Oregon, Dept Biol, Ecol & Evolut Program Eugene, OR 97403 USA Montana State Univ, Thermal Biol Inst Bozeman, MT 59717 USA <33> UI - 551TR-0003 DD - ISI Document Solution: 551TR AU - McEwan AG AU - Lewin A AU - Davy SL AU - Boetzel R AU - Leech A AU - Walker D AU - Wood T AU - Moore GR MA - mcewan@mailbox.uq.edu.au, g.moore@uea.ac.uk RA - McEwan AG TI - PrrC from Rhodobacter sphaeroides, a homologue of eukaryotic Sco proteins, is a copper-binding protein and may have a thiol-disulfide oxidoreductase activity SO - FEBS Letters. 518(1-3):10-16, 2002 May 8. AS - FEBS Lett 2002 May 8;518(1-3):10-16 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0014-5793 MH - Prrc MH - Sco MH - Cytochrome oxidase MH - Photosynthesis response regulation MH - Copper protein. MH - Cytochrome-c-oxidase MH - Gene-expression MH - Saccharomyces-cerevisiae MH - Chaperone MH - Yeast MH - Hsp33 MH - Metabolism MH - Domain MH - Cox17 MH - Motif. AB - PrrC from Rhodobacter sphaeroides provides the signal input to a two-component signal transduction system that senses changes in oxygen tension and regulates expression of genes involved in photosynthesis (Eraso, J.M. and Kaplan, S. (2000) Biochemistry, 39, 2052-2062; Oh, J.-I. and Kaplan, S. (2000) EMBO J. 19, 42374247). It is also a homologue of eukaryotic Sco proteins and each has a C-x-x-x-C-P sequence. In mitochondrial Sco proteins these cysteines appear to be essential for the biogenesis Of the Cu-A centre of respiratory cytochrome oxidase. Overexpression and purification of a water-soluble and monomeric form of PrrC has provided sufficient material for a chemical and spectroscopic study of the properties of the four cysteine residues of PrrC, and its ability to bind divalent cations, including copper. PrrC expressed in the cytoplasm of Escherichia coli binds Ni2+ tightly and the data are consistent with a mononuclear metal site. Following removal of Ni2+ and formation of renatured metal-free rPrrC (apo-PrrC), Cu2+ could be loaded into the reduced form of PrrC to generate a protein with a distinctive UV-visible spectrum, having absorbance with a lambda(max) of 360 nm. The copper:PrrC ratio is consistent with the presence of a mononuclear metal centre. The cysteines of metal-free PrrC oxidise in the presence of air to form two intramolecular disulfide bonds, with one pair being extremely reactive. The cysteine thiols with extreme O-2 sensitivity are involved in copper binding in reduced PrrC since the same copper-loaded protein could not be generated using oxidised PrrC. Thus, it appears that PrrC, and probably Sco proteins in general, could have both a thiol-disulfide oxidoreductase function and a copper-binding role. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies. [References: 36] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: McEwan AG Univ Queensland, Sch Mol & Microbial Sci Brisbane Qld 4072 Australia Univ Queensland, Sch Mol & Microbial Sci Brisbane Qld 4072 Australia Univ E Anglia, Sch Chem Sci Norwich NR4 7TJ Norfolk England Univ E Anglia, Sch Biol Sci Norwich NR4 7TJ Norfolk England <34> UI - 551TR-0018 DD - ISI Document Solution: 551TR AU - Conrad C AU - Schmitt JG AU - Evguenieva-Hackenberg E AU - Klug G MA - gabriele.klug@mikro.bio.uni-giessen.de RA - Klug G TI - One functional subunit is sufficient for catalytic activity and substrate specificity of Escherichia coli endoribonuclease III artificial heterodimers SO - FEBS Letters. 518(1-3):93-96, 2002 May 8. AS - FEBS Lett 2002 May 8;518(1-3):93-96 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0014-5793 MH - Rnase iii heterodimer MH - Rna processing MH - Dimeric enzyme. MH - Stranded-rna cleavage MH - Ribonuclease-iii MH - Rhodobacter-capsulatus MH - Processing signal MH - Binding domain MH - Dsrna-binding MH - Gene MH - Bacteriophage-t7 MH - Interference MH - Mechanism. AB - To study the intersubunit communication required for the activity of the normally homodimeric enzyme endoribonuclease III of Escherichia coli we have constructed and analysed an artificial heterodimer. This heterodimer is composed of one wild-type and one catalytically inactive subunit. The inactive subunit has one amino acid exchanged (E117K, rnc70 mutant) which abolishes cleavage activity but still allows substrate binding of a rnc70-homodimer. Our results show that one functional active site is sufficient for cleavage activity of the heterodimer. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. [References: 22] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Klug G Univ Giessen, Inst Mikro & Mol Biol Heinrich Buff Ring 26-32 D-35392 Giessen Germany Univ Giessen, Inst Mikro & Mol Biol D-35392 Giessen Germany <35> UI - 554HK-0007 DD - ISI Document Solution: 554HK AU - Talaga P AU - Cogez V AU - Wieruszeski JM AU - Stahl B AU - Lemoine J AU - Lippens G AU - Bohin JP MA - Jean-Pierre.Bohin@univ-lille1.fr RA - Bohin JP TI - Osmoregulated periplasmic glucans of the free-living photosynthetic bacterium Rhodobacter sphaeroides SO - European Journal of Biochemistry. 269(10):2464-2472, 2002 May. AS - Eur. J. Biochem 2002 May;269(10):2464-2472 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0014-2956 MH - Periplasm MH - Osmoregulation MH - Cyclic glucans. MH - Ionization mass-spectrometry MH - Assisted laser-desorption MH - Syringae pv syringae MH - Bradyrhizobium-japonicum MH - Burkholderia-solanacearum MH - Pseudomonas-syringae MH - Xanthomonas-campestris MH - Erwinia-chrysanthemi MH - Escherichia-coli MH - Beta-glucans. AB - The osmoregulated periplasmic glucans (OPGs) produced by Rhodobacter sphaeroides , a free-living organism, were isolated by trichloracetic acid treatment and gel permeation chromatography. Compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry and nuclear magnetic resonance. R. sphaeroides predominantly synthesizes a cyclic glucan containing 18 glucose residues that can be substituted by one to seven succinyl esters residues at the C-6 position of some of the glucose residues, and by one or two acetyl residues. The glucans were subjected to a mild alkaline treatment in order to remove the succinyl and acetyl substituents, analyzed by MALDI mass spectrometry and purified by high-performance anion-exchange chromatography. Methylation analysis revealed that this glucan is linked by 17 1,2 glycosidic bonds and one 1,6 glycosidic bond. Homonuclear and H-1/C-13 heteronuclear NMR experiments revealed the presence of a single alpha-1,6 glycosidic linkage, whereas all other glucose residues are beta-1,2 linked. The different anomeric proton signals allowed a complete sequence-specific assignment of the glucan. The structural characteristics of this glucan are very similar to the previously described OPGs of Ralstonia solanacearum and Xanthomonas campestris , except for its different size and the presence of substituents. Therefore, similar OPGs are synthesized by phytopathogenic as well as free-living bacteria, suggesting these compounds are intrinsic components of the Gram-negative bacterial envelope. [References: 37] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Bohin JP USTL, CNRS, UMR 8576, Unite Glycobiol Struct & Fonct Bat C9 F-59655 Villeneuve Dascq France USTL, CNRS, UMR 8576, Unite Glycobiol Struct & Fonct F-59655 Villeneuve Dascq France Inst Pasteur, Inst Biol Lille, CNRS, UMR 8525 F-59019 Lille France Milupa GmbH & Co KG, Res Int Friedrichsdorf Germany <36> UI - 554HK-0008 DD - ISI Document Solution: 554HK AU - Cogez V AU - Gak E AU - Puskas A AU - Kaplan S AU - Bohin JP MA - Jean-Pierre.Bohin@univ-lille1.fr RA - Bohin JP TI - The opgGIH and opgC genes of Rhodobacter sphaeroides form an operon that controls backbone synthesis and succinylation of osmoregulated periplasmic glucans SO - European Journal of Biochemistry. 269(10):2473-2484, 2002 May. AS - Eur. J. Biochem 2002 May;269(10):2473-2484 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0014-2956 MH - Periplasm MH - Osmoregulation MH - Cyclic glucans MH - Glucosyl transferase MH - Operon. MH - Escherichia-coli MH - Erwinia-chrysanthemi MH - Pseudomonas-syringae MH - Membrane-protein MH - Chromosome-ii MH - Pathogenicity MH - Locus MH - Dna MH - Biosynthesis MH - Mutagenesis. AB - Osmoregulated periplasmic glucans (OPGs) of Rhodobacter sphaeroides are anionic cyclic molecules that accumulate in large amounts in the periplasmic space in response to low osmolarity of the medium. Their anionic character is provided by the substitution of the glucosidic backbone by succinyl residues. A wild-type strain was subject to transposon mutagenesis, and putative mutant clones were screened for changes in OPGs by thin layer chromatography. One mutant deficient in succinyl substitution of the OPGs was obtained and the gene inactivated in this mutant was characterized and named opgC . opgC is located downstream of three ORFs, opgGIH , two of which are similar to the Escherichia coli operon, mdoGH , governing OPG backbone synthesis. Inactivation of opgG , opgI or opgH abolished OPG production and complementation analysis indicated that the three genes are necessary for backbone synthesis. In contrast, inactivation of a gene similar to ndvB , encoding the OPG-glucosyl transferase in Sinorhizobium meliloti , had no consequence on OPG synthesis in Rhodobacter sphaeroides . Cassette insertions in opgH had a polar effect on glucan substitution, indicating that opgC is in the same transcription unit. Expression of opgIHC in E. coli mdoB/mdoC and mdoH mutants allowed the production of slightly anionic and abnormally long linear glucans. [References: 35] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Bohin JP USTL, CNRS, UMR 8576, Unite Glycobiol Struct & Fonct Bat C9 F-59655 Villeneuve Dascq France USTL, CNRS, UMR 8576, Unite Glycobiol Struct & Fonct F-59655 Villeneuve Dascq France Univ Texas, Hlth Sci Ctr, Dept Microbiol & Mol Genet Houston, TX USA <37> UI - 554HK-0018 DD - ISI Document Solution: 554HK AU - Wehrle F AU - Appoldt Y AU - Kaim G AU - Dimroth P MA - dimroth@micro.biol.ethz.ch RA - Dimroth P TI - Reconstitution of F-o of the sodium ion translocating ATP synthase of Propionigenium modestum from its heterologously expressed and purified subunits SO - European Journal of Biochemistry. 269(10):2567-2573, 2002 May. AS - Eur. J. Biochem 2002 May;269(10):2567-2573 PU - BLACKWELL PUBLISHING LTD, P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND. URL: http://www.blackwell-science.com IS - 0014-2956 MH - Atp synthase MH - F-o MH - Reconstitution MH - Na+ translocation MH - Subunit a MH - Subunit b. MH - Escherichia-coli MH - Over-production MH - Cross-linking MH - Delta-subunit MH - B-subunit MH - F-0 motor MH - 2nd stalk MH - Na+ MH - F1f0 MH - Dicyclohexylcarbodiimide. AB - The atp B and atp F genes of Propionigenium modestum were cloned as His-tag fusion constructs and expressed in Escherichia coli. Both recombinant subunits a and b were purified via Ni2+ chelate affinity chromatography. A functionally active F-o complex was reassembled in vitro from subunits a, b and c, and incorporated into liposomes. The F-o liposomes catalysed Na-22(+) uptake in response to an inside negative potassium diffusion potential, and the uptake was prevented by modification of the c subunits with N,N'- dicyclohexylcarbodiimide (DCCD). In the absence of a membrane potential the F-o complexes catalysed Na-22(+) (out) /Na+ (in)-exchange. After F-1 addition the F1Fo complex was formed and the holoenzyme catalysed ATP synthesis, ATP dependent Na+ pumping, and ATP hydrolysis, which was inhibited by DCCD. Functional F-o hybrids were reconstituted with recombinant subunits a and b from P. modestum and c(11) from Ilyobacter tartaricus . These F-o hybrids had Na+ translocation activities that were not distinguishable from that of P. modestum F-o . [References: 36] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Dimroth P ETH Zentrum, Inst Mikrobiol CH-8092 Zurich Switzerland ETH Zentrum, Inst Mikrobiol CH-8092 Zurich Switzerland <38> UI - 554BX-0006 DD - ISI Document Solution: 554BX AU - Singh DP AU - Kshatriya K RA - Singh DP TI - NaCl-induced oxidative damage in the cyanobacterium Anabaena doliolum SO - Current Microbiology. 44(6):411-417, 2002 Jun. AS - Curr. Microbiol 2002 Jun;44(6):411-417 PU - SPRINGER-VERLAG, 175 FIFTH AVE, NEW YORK, NY 10010 USA. URL: http://www.springer-ny.com IS - 0343-8651 MH - Anacystis-nidulans MH - Superoxide-dismutase MH - Tolerant mutant MH - Photosystem-ii MH - Salt stress MH - Photosynthesis MH - Oxygen MH - Light MH - Chloroplasts MH - Fluorescence. AB - Results obtained with graded concentrations of NaCl (20-200 mm) show decrease in the chlorophyll 'a' contents of Anabaena with increasing concentration of NaCl except at extremely low concentration of NaCl (5-20 mm). The rate of Hill activity and oxygen evolution are found to be stimulated by lower concentrations of NaCl, but not at higher concentrations of NaCl. Results have demonstrated that the O-2 evolution process is relatively more sensitive to NaCl stress than the Hill activity. Further, the results show NaCl induced an increase in the rate of RNO bleaching and loss of total thiol (-SH) contents. Taken together, these results suggest a NaCl-induced general oxidative stress. Results on the effect of oxygen radical quenchers reveal a predominant role of singlet oxygen in the NaCl-induced general oxidative stress as evident from a higher quenching effect of sodium azide than formate and histidine on the rate of RNO bleaching in Anabaena cells. However, the rate of lipid peroxidation and SOD activity show a declining pattern in response to increasing concentrations of NaCl. There is the possibility of a NaCl-induced decrease in the rate of lipid peroxidation when the SOD activity is also lower. But the NaCl-induced decline in the SOD activity does suggest that symptoms of general oxidative stress at elevated levels of NaCl are apparently owing to collapse of intracellular defense of the cells against the toxic oxygen radicals, not because of the higher rate of photosynthetic activity. [References: 37] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Microbiology in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Singh DP Babasaheb Bhimrao Ambedkar Univ, Sch Environm Sci Rae Bareli Rd Lucknow 226025 Uttar Pradesh India Dr RML Avadh Univ, Dept Microbiol Faizabad 224001 Uttar Pradesh India <39> UI - 552CF-0009 DD - ISI Document Solution: 552CF AU - Lin RC AU - Li LB AU - Kuang TY MA - lbli@ns.ibcas.ac.cn, kuangty@ns.ibcas.ac.cn RA - Li LB TI - Molecular cloning, in vitro expression and enzyme activity analysis of violaxanthin de-epoxidase from Oryza sativa L. SO - Chinese Science Bulletin. 47(11):915-917, 2002 Jun. AS - Chin. Sci. Bull 2002 Jun;47(11):915-917 PU - SCIENCE PRESS, 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA. URL: http://www.scichina.com IS - 1001-6538 MH - Oryza sativa l. MH - Violaxanthin de-epoxidase MH - Clone MH - Expression MH - Enzyme activity. MH - Xanthophyll cycle MH - Escherichia-coli MH - Light. AB - The violaxanthin de-epoxidase gene was cloned from rice (Oryza sativa subsp. japonica). The full length of the cDNA is 1887 bp, encoding a 446-amino acids protein with the transit peptide of 98 amino acids. The bacterial expression vector pET-Rvde was constructed and the expression quantity of the exogenous protein increased with the induction time by 0.4 mmol/L IPTG. Its molecular weight was similar with that of the native VDE. Western blotting indicated that the expressed protein has immunological reaction with the VDE polyclonal antibody. The absorbance spectrum together with xanthophyll pigments quantification by HPLC demonstrated that the expressed VDE has its enzyme activity, which can de-epoxidate violaxanthin into antheraxanthin and zeaxanthin in vitro. [References: 12] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences CC - Multidisciplinary in Current Contents(R)/Physical, Chemical & Earth Sciences. EW - 2002 week 24 IN - Reprint available from: Li LB Chinese Acad Sci, Photosynth Res Ctr, Inst Bot Beijing 100093 Peoples R China Chinese Acad Sci, Photosynth Res Ctr, Inst Bot Beijing 100093 Peoples R China <40> UI - 552PX-0007 DD - ISI Document Solution: 552PX AU - Jemiola-Rzeminska M AU - Mysliwa-Kurdziel B AU - Strzalka K MA - strzalka@mol.uj.edu.pl RA - Strzalka K TI - The influence of structure and redox state of prenylquinones on thermotropic phase behaviour of phospholipids in model membranes SO - Chemistry & Physics of Lipids. 114(2):169-180, 2002 Feb. AS - Chem. Phys. Lipids 2002 Feb;114(2):169-180 PU - ELSEVIER SCI IRELAND LTD, CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND. URL: http://www.elsevier.nl IS - 0009-3084 MH - Plastoquinone MH - Ubiquinone MH - Liposome MH - Phospholipid bilayer MH - Phase transition MH - Dsc. MH - Differential scanning calorimetry MH - Coenzyme-q MH - Phosphatidylcholine bilayers MH - Fluorescence anisotropy MH - Alpha-tocopherol MH - Chain-length MH - Side-chain MH - Ubiquinones MH - Plastoquinone MH - Vesicles. AB - Our study was aimed to investigate the significance of the isoprenoid side chain size as well as redox state of the quinone ring for interaction of two main classes of prenylquinones: plastoquinones (PQ) and ubiquinones (UQ) with lipid bilayers. By use of differential scanning calorimetry (DSC) we have followed the thermotropic behaviour of multilamellar vesicles prepared from dipalmitoylphosphatidylcholine (DPPC) upon incorporation of increasing amount (1.3-12 mol%) of quinone (quinol) molecules. Our studies reveal that as the side chain is shorter (from 9 to 2 isoprenoid units) the height of the calorimetric profiles is reduced and the temperature of the main transition of DPPC (T-m) decreases (T-m = 39.4 degreesC for a sample with 12 mol% of PQ-2), and then increases up to 39.8 degreesC for PQ-1. For the samples containing quinols the effect is more pronounced even at lower concentration. The greater influence of the added prenylquinones on the pretransition demonstrates a stronger distortion of the DPPC packing in the gel state. It seems that this is the isoprenoid side chain length rather than the redox state of prenylquinones that determines their effectiveness in perturbation of thermotropic properties of lipid bilayer. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. [References: 50] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Strzalka K Jagiellonian Univ, Dept Plant Physiol & Biochem, Jan Zurzycki Inst Mol Biol Ul Gronostajowa 7 PL-30387 Krakow Poland Jagiellonian Univ, Dept Plant Physiol & Biochem, Jan Zurzycki Inst Mol Biol PL-30387 Krakow Poland <41> UI - 553TH-0010 DD - ISI Document Solution: 553TH AU - Vimalabai CPM AU - Kulandaivelu G MA - gkplant1@sify.com RA - Kulandaivelu G TI - Effects of prolonged UV-B enhanced fluorescent radiation on some marine microalgae SO - Biologia Plantarum. 45(3):389-394, 2002. AS - Biol. Plant 2002;45(3):389-394 PU - KLUWER ACADEMIC PUBL, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS. URL: http://www.wkap.nl IS - 0006-3134 MH - Chlorophyll MH - Fluorescence spectra MH - Photosynthetic electron transport MH - Phytoplankton MH - Thylakoid proteins. MH - Photosynthetic electron-transport MH - Flagellate cryptomonas-maculata MH - Protein complexes MH - Oxygen production MH - Euglena-gracilis MH - Chlorophyll MH - Phytoplankton MH - Assimilation MH - Chloroplasts MH - Inhibition. AB - The eukaryotic unicellular microalgae Chlorella salina, Dicrateria inornata, and Isochrysis galbana were grown under control (fluorescent 20 W m(-2)) and UV-B enhanced (UV-B-E, 0.5 W m(-2)) fluorescent radiation. The growth rate showed marginal increase under UV-B-E. Decrease in protein content was observed in Dicrateria cells but in Chlorella an initial increase up to 4 d and in Isochrysis an increase at days 4 and 5 was noted. The chlorophyll a content showed marked increase in Chlorella and Isochrysis but in Dicrateria a decline was found. UV-B-E reduced the photosynthetic activity in all three species, but the reduction was larger in Chlorella and Dicrateria. Fluorescence excitation spectra for F-682 in Chlorella cells grown for 5 d under UV-B-E showed reduction in all peaks. In contrast to this, in Dicrateria and Isochrysis cells, the 530 and 590 rim excitation peaks increased with an appreciable decrease in the 466 nm peak. SDS-PAGE analysis revealed significant decrease in the contents of 47, 33, and 23 kDa polypeptides in Chlorella cells. In Dicrateria cells, significant loss in the content of 55, 38, and 18 kDa polypeptides was observed. The content of low molecular mass polypeptides (15 kDa) remained unaffected. Isochrysis cells were more stable in preserving the content of thylakoid polypeptides. [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 - 2002 week 24 IN - Reprint available from: Kulandaivelu G Madurai Kamaraj Univ, Sch Biol Sci Madurai 625021 Tamil Nadu India Madurai Kamaraj Univ, Sch Biol Sci Madurai 625021 Tamil Nadu India <42> UI - 552FB-0016 DD - ISI Document Solution: 552FB AU - Yu M AU - Jaradat SA AU - Grossman LI MA - l.grossman@wayne.edu RA - Grossman LI TI - Genomic organization and promoter regulation of human cytochrome c oxidase subunit VII heart/muscle isoform (COX7AH) SO - Biochimica et Biophysica Acta - Gene Structure & Expression. 1574(3):345-353, 2002 Apr 12. AS - Biochim. Biophys. Acta-Gene Struct. Expression 2002 Apr 12;1574(3):345-353 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0167-4781 MH - Complex iv MH - Basal promoter MH - Gene sequence. MH - Dna-binding domain MH - Iv gene MH - Structural organization MH - Transcription factors MH - Nucleotide-sequence MH - Gel-electrophoresis MH - Heart isoform MH - Atp synthase MH - Bovine gene MH - Expression. AB - We have isolated and characterized the human gene (COX7AH) for the contractile muscle isoform of cytochrome c oxidase (COX) subunit VIIa. This subunit is one of the 10 nuclear encoded subunits of the 13-subunit holoenzyme that carries out the terminal step in the electron transport chain. Using transient transfection assays, we have located a 5'-flanking region sufficient to direct high level, skeletal myotube-specific reporter gene expression. This 792 bp basal promoter, which contains the single transcription start but no canonical TATA or CCAAT boxes, contains one MEF2 site, three E boxes, and an Spl site that show binding to their cognate factors, and are all required for full expression. Mutation and transactivation analysis suggest that there is functional interaction between these binding sites. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 48] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Molecular Biology & Genetics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Grossman LI Wayne State Univ, Sch Med, Ctr Mol Med & Genet Detroit, MI 48201 USA Wayne State Univ, Sch Med, Ctr Mol Med & Genet Detroit, MI 48201 USA <43> UI - 552FA-0001 DD - ISI Document Solution: 552FA AU - Klishin SS AU - Junge W AU - Mulkidjanian AY MA - mulkidjanian@biologie.uni-osnabrueck.de RA - Mulkidjanian AY TI - Flash-induced turnover of the cytochrome bc1 complex in chromatophores of Rhodobacter capsulatus: binding of Zn2+ decelerates likewise the oxidation of cytochrome b, the reduction of cytochrome c(1) and the voltage generation SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):177-182, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):177-182 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Electron transfer MH - Proton transfer MH - Coupling MH - Protonmotive force MH - Rhodobacter sphaeroides. MH - Iron-sulfur protein MH - Bc(1) complex MH - Electron-transfer MH - Rhodopseudomonas-sphaeroides MH - Oxygenic photosynthesis MH - Proton release MH - B(6)f complex MH - Bovine heart MH - Q-cycle MH - Chain. AB - The effect of Zn2+ on the rates of electron transfer and of voltage generation in the cytochrome bc(1) complex (bc(1)) was investigated under excitation of Rhodobacter capsulatus chromatophores with flashing light. When added, Zn2+ retarded the oxidation of cytochrome b and allowed to monitor (at 561-570 nm) the reduction of its high potential heme b(h) (in the absence of Zn2+ this reaction vas masked by the fast re-oxidation of the heme). The effect was accompanied by the deceleration of both the cytochrome c(1) reduction (as monitored at 552-570 nm) and the generation of transmembrane voltage (monitored by electrochromism at 522 nm). At Zn2+ < 100 muM the reduction of heme b(h) remained 10 times faster than other reactions. The kinetic discrepancy was observed even after an attenuated flash, when bc(1) turned over only once. These observations (1) raise doubt on the notion that the transmembrane electron transfer towards heme b(h) is the main electrogenic reaction in the cytochrome bc(1) complex, (2) imply an allosteric link between the site of heme b(h) oxidation and the site of cytochrome c(1) reduction at the opposite side of the membrane, and (3) indicate that the internal redistribution of protons might account for the voltage generation by the cytochrome bc(1) complex. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 30] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Mulkidjanian AY Univ Osnabruck, Dept Biol & Chem, Div Biophys D-49069 Osnabruck Germany Univ Osnabruck, Dept Biol & Chem, Div Biophys D-49069 Osnabruck Germany Moscow MV Lomonosov State Univ, AN Belozersky Inst Physicochem Biol Moscow 119899 Russia <44> UI - 552FA-0003 DD - ISI Document Solution: 552FA AU - Senior AE AU - Nadanaciva S AU - Weber J MA - alan_senior@urmc.rochester.edu RA - Senior AE TI - The molecular mechanism of ATP synthesis by F1F0-ATP synthase [Review] SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):188-211, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):188-211 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Atp synthesis MH - Oxidative phosphorylation MH - F1f0-atp synthase MH - Molecular mechanism MH - Catalytic site MH - Subunit rotation. MH - Escherichia-coli f1-atpase MH - Thermophilic bacillus ps3 MH - Heart mitochondrial atpase MH - Catalytic transition-state MH - Nucleotide-binding-sites MH - Defective proton-atpase MH - C-subunit oligomer MH - Gamma-subunit MH - Delta-subunit MH - Beta-subunit. AB - ATP synthesis by oxidative phosphorylation and photophospliorylation. catalyzed by F1F0-ATP synthase, is the fundamental means of cell energy production. Earlier mutagenesis studies had gone some way to describing the mechanism. More recently, several Xray structures at atomic resolution have pictured the catalytic sites, and real-time video recordings of subunit rotation have left no doubt of the nature of energy coupling between the transmembrane proton gradient and the catalytic sites in this extraordinary molecular motor. Nonetheless, the molecular events that are required to accomplish the chemical synthesis of ATP remain undefined. In this review we summarize current state of knowledge and present a hypothesis For the molecular mechanism of ATP synthesis. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 152] LG - English PT - Review SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Senior AE Univ Rochester, Med Ctr, Dept Biochem & Biophys Box 712,601 Elmwood Ave Rochester, NY 14642 USA Univ Rochester, Med Ctr, Dept Biochem & Biophys Rochester, NY 14642 USA <45> UI - 552FA-0004 DD - ISI Document Solution: 552FA AU - O'Malley PJ MA - p.o'malley@umist.ac.uk RA - O'Malley PJ TI - Density functional calculations modelling tyrosine oxidation in oxygenic photosynthetic electron transfer SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):212-217, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):212-217 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Photosystem-ii MH - Difference spectroscopy MH - Complexes MH - Phenoxyl MH - Oxidase. AB - Hybrid density functional calculations are used to model tyrosine oxidation during electron transfer reactions of photosystem II. The predicted frequency values tor the 7a and deltaCOH modes of the reduced form and the 7a mode of the oxidised radical form are in excellent agreement with experimental data obtained for Mn and Ca depleted systems by Hienerwadel et al. [Biochemistry 36 (1997) 15447] and Berthomieu et al. [Biochemistry 37 (1998) 105471, The calculations confirm that the two tyrosines Y-D and Y-Z are protonated in the reduced form. On oxidation the larger 7a frequency value observed experimentally for Y-Z. can be best explained by a greater localisation of the protonic charge released on formation of this tyrosyl free radical. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 22] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 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 <46> UI - 552FA-0011 DD - ISI Document Solution: 552FA AU - David P AU - Baumann M AU - Wikstrom M AU - Finel M MA - moshe.finel@helsinki.fi RA - Finel M TI - Interaction of purified NDH-1 from Escherichia coli with ubiquinone analogues SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):268-278, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):268-278 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Complex i MH - Nadh dehydrogenase MH - Matrix assisted laser desorption/ionization time of flight MH - Ubiquinone-2 MH - Respiratory chain MH - Phospholipid. MH - Oxidoreductase complex-i MH - Proton-translocating nadh MH - Dihydroorotate dehydrogenase MH - Proteins MH - Gene MH - Dicyclohexylcarbodiimide MH - Electrophoresis MH - Components MH - Reduction MH - Sequence. AB - The NADH:ubiquinone oxidoreductase (NDH-1 or Complex I) of Escherichia coli is a smaller version of the mitochondrial enzyme, being composed of 13 protein subunits in comparison to the 43 of bovine heart complex I. The bacterial NDH-1 from an NDH-2-deficient strain was purified using a combination of anion exchange chromatography and sucrose gradient centrifugation. All 13 different subunits were detected in the purified enzyme by either N-terminal sequencing or matrix-assisted laser desorption/ionization time-of-flight mass spectral analysis, In addition, some minor contaminants were observed and identified. The activity of the enzyme was studied and the effects of phospholipid and dodecyl maltoside were characterized. Kinetic analyses were performed for the enzyme in the native membrane as well as for the purified NDH-1. using ubiquinone-1. ubiquinone-2 or decylubiquinone as the electron acceptors. The purified enzyme exhibited between 1.5- and 4-fold increase in the apparent K-m for these acceptors. Both ubiquinone-2 and decylubiquinone are good acceptors for this enzyme, while affinity of NDH-1 for ubiquinone-1 is clearly lower than for the other two, particularly in the purified state. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 27] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Finel M Univ Helsinki, Dept Pharm, Mol Biol Unit, Viikki DDTC,Dept Pharm POB 56 Viikinkaari 5F FIN-00014 Helsinki Finland Univ Helsinki, Bioctr 2, Inst Biotechnol, Helsinki Bioenerget Grp FIN-00014 Helsinki Finland Univ Helsinki, Inst Biomed, Prot Chem Unit FIN-00014 Helsinki Finland <47> UI - 552FA-0012 DD - ISI Document Solution: 552FA AU - Neuschaefer-Rube O AU - Boger P AU - Ernst A MA - olaf.neuschaefer.rube@folkehelsa.no RA - Neuschaefer-Rube O TI - Interference of an apcA insertion with complementary chromatic adaptation in the diazotrophic Synechocystis sp strain BO 8402 SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):279-295, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):279-295 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Nitrogen metabolism MH - Phycoerythrin MH - Complementary chromatic adaptation MH - Internal signaling MH - Cyanobacterium MH - Synechocystis. MH - Cyanobacterium fremyella-diplosiphon MH - P-ii protein MH - Photosynthetic apparatus MH - Regulated expression MH - Rod substructure MH - Lake constance MH - Photosystem-i MH - Light signal MH - Phycoerythrin MH - Phycobilisomes. AB - Complementary chromatic adaptation was studied in two unicellular diazotrophic Synechocystis-type cyanobacteria. strains BO 8402 and BO 9201. Strain BO 8402 was isolated from Lake Constance as a mutant lacking phycobilisomes due to an insertion sequence element in the gene apcA. encoding alpha-allophycocyanin. Strain BO 9201 recovered the ability to assemble functional phycobilisomes after a spontaneous excision of the insertion sequence element in apcA. Simultaneously, the strain became able to perform group 11 complementary chromatic adaptation by regulating the synthesis of phycoerythrin. The two strains had identical phycoerythrin operons, cpeBA. and similar-sized transcripts were formed upon induction by green light, However. in strain BO 8402 the cpeBA transcript level was approx. 20-fold lower than in strain BO 9201. Because strain BO 8402 cannot synthesize allophycocyanin and phycocyanin is sequestered in paracrystalline inclusion bodies, non-assembled phycoerythrin may accumulate inside the cells. It as examined whether non-assembled phycoerythrin or other effects caused by the absence of phycobilisomes. such as a permanently oxidized redox status of the photosynthetic electron transport chain or a distorted ratio of C and N assimilation mediated the repression of cpeBA transcription in strain BO 8402. No such links could be established. We therefore concluded that in these diazotrophic Synechocystis-type cyanobacteria the green light-induced transcription of the cpe operon directly required a functional apc operon. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 48] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Neuschaefer-Rube O Natl Inst Publ Hlth POB 4404 N-0403 Oslo Norway Univ Konstanz, Lehrstuhl Physiol & Biochem Pflanzen D-78457 Constance Germany NIOO, Ctr Estuarine & Coastal Ecol NL-4400 AC Yerseke Netherlands <48> UI - 552FA-0013 DD - ISI Document Solution: 552FA AU - Valiyaveetil F AU - Hermolin J AU - Fillingame RH MA - rhfillin@facstaff.wisc.edu RA - Fillingame RH TI - pH dependent inactivation of solubilized F1F0 ATP synthase by dicyclohexylcarbodiimide: pK(a) of detergent unmasked aspartyl-61 in Escherichia coli subunit c SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):296-301, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):296-301 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Atp synthase MH - Subunit c MH - Essential carboxyl MH - Dicyclohexylcarbodiimide MH - Ph dependence MH - Atpase inhibition MH - Proton transport. MH - Water-soluble carbodiimides MH - H+-atpase MH - Oxidative-phosphorylation MH - Propionigenium-modestum MH - Essential carboxyl MH - Coupling ions MH - F-atpase MH - Oligomer MH - Motor MH - F-0. AB - The pH dependence of the reaction of dicyclohexylcarbodiimide with the essential aspartyl-61 residue in subunit c of Escherichia coli ATP synthase was compared in membranes and in a detergent dispersed preparation of the enzyme. The rate of reaction was estimated by measuring the inactivation of ATPase activity. The reaction with the detergent dispersed form of the enzyme proved to be pH sensitive with the essential aspartyl group titrating A with a pK(a), = 8. However, when measured with E. coli membranes, the reaction proved to be pH insensitive. The results suggest that the reacting aspartyl-61 residues are shielded from the bulk aqueous solvent when in the membrane, but then become aqueous-accessible following detergent solubilization. (C) 2002 Published by Elsevier Science B.V. [References: 38] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Fillingame RH Univ Wisconsin, Sch Med, Dept Biomol Chem 1300 Univ Ave Madison, WI 53706 USA Univ Wisconsin, Sch Med, Dept Biomol Chem Madison, WI 53706 USA <49> UI - 552FA-0015 DD - ISI Document Solution: 552FA AU - Lokstein H AU - Tian L AU - Polle JEW AU - DellaPenna D MA - lokstein@mbi-berlin.de RA - Lokstein H TI - Xanthophyll biosynthetic mutants of Arabidopsis thaliana: altered nonphotochemical quenching of chlorophyll fluorescence is due to changes in Photosystem II antenna size and stability SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):309-319, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):309-319 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Antenna size MH - Carotenoid MH - Lutein MH - Nonphotochemical quenching of chlorophyll fluorescence MH - Photoprotection MH - Xanthophyll MH - Arabidopsis thaliana. MH - Light-harvesting complex MH - Photosynthetic membranes MH - Scenedesmus-obliquus MH - Binding proteins MH - Higher-plants MH - Green-alga MH - Photoprotection MH - Stoichiometry MH - Lutein MH - Leaves. AB - Xanthophylls (oxygen derivatives of carotenes) are essential components of the plant photosynthetic apparatus. Lutein. the most abundant xanthophyll. is attached primarily to the bulk antenna complex. light-harvesting complex (LHC) II. We have used mutations in Arabidopsis thaliana that selectively eliminate (and substitute) specific xanthophylls in order to study their function(s) in vivo. These include two lutein-deficient mutants, lut1 and lut2, the epoxy xanthophyll-deficient aba1 mutant and the lut2aba1 double mutant, Photosystem stoichiometry. antenna sizes and xanthophyll cycle activity have been related to alterations in nonphotochemical quenching of chlorophyll fluorescence (NPQ). Nondenaturing polyacrylamide gel electrophoresis indicates reduced stability of trimeric LHC II in the absence of lutein (and/or epoxy xanthophylls). Photosystem (antenna) size and stoichiometry is altered in all mutants relative to wild type (WT). Maximal DeltapH-dependent NPQ (qE) is reduced in the following order: WT > aba1 > lut1 = lut2 > lut2aba1. paralleling reduction in Photosystem (PS) II antenna size. Finally, light-activation of NPQ shows that zeaxanthin and antheraxanthin present constitutively in lut mutants are not qE active. and hence. the same can be inferred of the lutein they replace. Thus, a direct involvement of lutein in the mechanism of qE is unlikely. Rather. altered NPQ in xanthophyll biosynthetic mutants is explained by disturbed macro-organization of LHC II and reduced PS II-antenna size in the absence of the optimal, wildtype xanthophyll composition. These data suggest the evolutionary conservation of lutein content in plants was selected for due to its unique ability to optimize antenna structure. stability and macro-organization for efficient regulation of light-harvesting under natural environmental conditions. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 32] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Lokstein H Humboldt Univ, Inst Biol Pflanzenphysiol Untere Linden 6 Sitzl Philippstr 13 D-10099 Berlin Germany Humboldt Univ, Inst Biol Pflanzenphysiol D-10099 Berlin Germany Michigan State Univ, Dept Biochem & Mol Biol E Lansing, MI 48824 USA Univ Calif Berkeley, Dept Plant & Microbial Biol Berkeley, CA 94720 USA <50> UI - 552FA-0016 DD - ISI Document Solution: 552FA AU - Mezzetti A AU - Nabedryk E AU - Breton J AU - Okamura MY AU - Paddock ML AU - Giacometti G AU - Leibl W MA - leibl@dsvidf.cea.fr RA - Leibl W TI - Rapid-scan Fourier transform infrared spectroscopy shows coupling of GLu-L212 protonation and electron transfer to Q(B) in Rhodobacter sphaeroides reaction centers SO - Biochimica et Biophysica Acta - Bioenergetics. 1553(3):320-330, 2002 Feb 15. AS - Biochim. Biophys. Acta-Bioenerg 2002 Feb 15;1553(3):320-330 PU - ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS. URL: http://www.elsevier.nl IS - 0005-2728 MH - Proton uptake MH - Bacterial photosynthesis MH - Proton-coupled electron transfer MH - Site-directed mutation MH - Rhodobacter sphaeroides. MH - Bacterial reaction centers MH - Photosynthetic reaction-center MH - Ftir difference spectroscopy MH - R26 reaction centers MH - Rhodopseudomonas-sphaeroides MH - Binding-sites MH - Quinones MH - Protein MH - Pathway MH - Reduction. AB - Rapid-scan Fourier transform infrared (FTIR) difference spectroscopy was used to investigate the electron transfer reaction Q(A)(-)Q(B) --> Q(A)Q(B) (k(AB)) in mutant reaction centers of Rhodobacter sphaeroides, where Asp-L210 and/or Asp-M17 hake been replaced with Asn. Mutation of both residues decreases drastically k(AB), attributed to slow proton transfer to Glu-L212, which becomes rate limiting for electron transfer to Q(B) [M.L Paddock et al. Biochemistry 40 (2001) 6893]. In the double mutant, the FTIR difference spectrum recorded during the time window 4-29 ms following a flash showed peaks at 1670 (-), 1601 (-) and 1467 (+) cm(-1) characteristic of Q(A) reduction. The time evolution of the spectra shows reoxidation of Q(A)(-) and concomitant reduction of Q(B) with a kinetics of about 40 ms. In native reaction centers and in both single mutants. formation of Q(B) occurs much faster than in the double mutant. Within the time resolution of the technique. protonation of Glu-L212, as characterized by an absorption increase at 1728 cm(-1) [E. Nabedryk et al., Biochemistry 34 (1995) 14722]. was found to proceed with the same kinetics as reduction of Q(B) in all samples. These rapid-scan FTIR results support the model of proton uptake being rate limiting for the First electron transfer from Q(A) to Q(B) and the identification of Glu-L212 as the main proton acceptor in the state Q(A)Q(B)(-). (C) 2002 Elsevier Science B.V. All rights reserved. [References: 44] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Leibl W CEA Saclay, Sect Bioenerget Bat 532 F-91191 Gif Sur Yvette France CEA Saclay, Sect Bioenerget F-91191 Gif Sur Yvette France Dept Phys Chem A Miolati I-35100 Padua Italy Univ Calif San Diego, Dept Phys La Jolla, CA 92093 USA <51> UI - 552ZX-0032 DD - ISI Document Solution: 552ZX AU - Johnson ET AU - Parson WW MA - parsonb@u.washington.edu RA - Parson WW TI - Electrostatic interactions in an integral membrane protein SO - Biochemistry. 41(20):6483-6494, 2002 May 21. AS - Biochemistry 2002 May 21;41(20):6483-6494 PU - AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA. URL: http://www.pubs.acs.org IS - 0006-2960 MH - Photosynthetic reaction centers MH - Bacterial reaction centers MH - Molecular-dynamics simulation MH - Charge-charge interactions MH - Amino-acid-residues MH - Rhodobacter-sphaeroides MH - Free-energy MH - Dielectric-constants MH - Proton-transfer MH - Solvent models. AB - The effects of charge-charge interactions on the midpoint reduction potential (E) of the primary electron donor (P) in the photosynthetic reaction center of Rhodobacter sphaeroides were investigated by introducing mutations of ionizable amino acids at selected sites. The mutations were designed to alter the electrostatic environment of P, a bacteriochlorophyll dimer, without greatly affecting its structure or molecular orbitals. Two arginine residues at homologous positions in the L and M subunits [residues (L135) and (M164)], Asp (L155), Tyr (L164), and Cys (L247) were changed independently. Arginine (L135) was replaced by Lys, Leu, Gln, or Glu; Arg (M164), by Leu or Glu; Asp (L155), by Asn; Tyr (L164), by Phe; and Cys (L247), by Lys or Asp. The R(L135)E/C(L247)K double mutant also was made. The shift in the E-m of P/P+ was measured in each mutant and was compared with the effect predicted by electrostatics calculations using several different computational approaches. A simple distance-dependent dielectric screening factor reproduced the effects remarkably well. By contrast, microscopic methods that considered the reaction field in the protein and solvent but did not include explicit counterions overestimated the changes in the E,, considerably. Including counterions for the charged residues reduced the calculated effects of the mutations in molecular dynamics calculations. The results show that electrostatic interactions of P with ionizable amino acid residues are strongly screened, and suggest that counterions make major contributions to this screening. The screening also could reflect penetration of water or other relaxations not taken into account because of incomplete sampling of configurational space. [References: 85] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Parson WW Univ Washington, Dept Biochem Box 357350 Seattle, WA 98195 USA Univ Washington, Dept Biochem Seattle, WA 98195 USA <52> UI - 552ZZ-0043 DD - ISI Document Solution: 552ZZ AU - Butler CS AU - Fairhurst SA AU - Ferguson SJ AU - Thomson AJ AU - Berks BC AU - Richardson DJ AU - Lowe DJ MA - david.lowe@bbsrc.ac.uk RA - Butler CS TI - Mo(V) co-ordination in the periplasmic nitrate reductase from Paracoccus pantotrophus probed by electron nuclear double resonance (ENDOR) spectroscopy SO - Biochemical Journal. 363(Part 3):817-823, 2002 May 1. AS - Biochem. J 2002 May 1;363(Part 3):817-823 PU - PORTLAND PRESS, 59 PORTLAND PLACE, LONDON W1N 3AJ, ENGLAND. URL: http://www.portlandpress.co.uk IS - 0264-6021 MH - Cysteine MH - Epr MH - Molybdoenzymes MH - Molybdopterin guanine dinucleotide (mgd) MH - Protons. MH - Crystal-structure MH - Thiosphaera-pantotropha MH - Rhodobacter-capsulatus MH - Xanthine-oxidase MH - Angstrom resolution MH - Molybdenum center MH - Dmso reductase MH - Denitrificans MH - Signals MH - Cluster. AB - The first electron nuclear double resonance (ENDOR) study of a member of the Mo-bis-molybdopterin guanine dinucleotide family of molybdoenzymes is presented, using the periplasmic nitrate reductase from Paracoccus pantotrophus. Rapid freeze-quenched time-resolved EPR revealed that during turnover the intensity of a Mo(V) EPR signal known as High-g [resting] increases. This signal is split by two interacting protons that are not solvent-exchangeable. X-band proton-ENDOR analysis resolved broad symmetrical resonance features that arose from four classes of protons weakly coupled to the Mo(V). Signals from two of these were lost upon exchange into deuterated buffer, suggesting that they may originate from OH- or H2O groups. One of these signals was also lost when the enzyme was redox-cycled in the presence of azide. Since these protons are very weakly coupled OH/H2O groups, they are not likely to be ligated directly to the Mo(V). This suggests that protonation of a Mo(VI)=O group does not occur on reduction to Mo(V), but most probably accompanies reduction of Mo(V) to Mo(IV). A resonance feature from a more strongly coupled proton, that was not lost following exchange into deuterated buffer, could also be resolved at 22-24 MHz. The anisotropy of this feature, determined from ENDOR spectra collected at a range of field positions, indicated a Mo-proton distance of approx. 3.2 Angstrom, consistent with this being one of the beta-methylene protons of a Mo-Cys ligand. [References: 26] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Butler CS John Innes Ctr, Dept Biol Chem Colney Lane Norwich NR4 7UH Norfolk England John Innes Ctr, Dept Biol Chem Norwich NR4 7UH Norfolk England Univ E Anglia, Sch Biol Sci, Ctr Metalloprot Spect & Biol Norwich NR4 7TJ Norfolk England Univ E Anglia, Sch Chem Sci, Ctr Metalloprot Spect & Biol Norwich NR4 7TJ Norfolk England Univ Oxford, Dept Biochem Oxford OX1 3QU England <53> UI - 554CT-0021 DD - ISI Document Solution: 554CT AU - Cook RW AU - Jolly RD AU - Palmer DN AU - Tammen I AU - Broom MF AU - McKinnon R RA - Cook RW TI - Neuronal ceroid lipofuscinosis in Merino sheep SO - Australian Veterinary Journal. 80(5):292-297, 2002 May. AS - Aust. Vet. J 2002 May;80(5):292-297 PU - AUSTRALIAN VETERINARY ASSN, 272 BRUNSWICK RD BRUNSWICK, MELBOURNE, VIC 3056, AUSTRALIA. URL: http://www.ava.com.au IS - 0005-0423 MH - Mitochondrial atp synthase MH - Battens-disease MH - Variant cln6 MH - Ovine model MH - Protein MH - Storage MH - Pathogenesis MH - Subunit MH - Ncl. AB - Objective To characterise neuronal ceroid lipofuscinosis (NCL) in Merino sheep. Design A prospective clinical, pathological, biochemical and genetic study. Procedure NCL cases were studied from a medium-wool Merino flock, the stud of origin of its replacement rams, and an experimental flock established at the University of Sydney. Results Behavioural changes and visual impairment were first detected at 7 to 12 months of age and progressed, with associated motor disturbances and at later stages seizures, to premature death by 27 months of age. At necropsy there was severe cerebrocortical atrophy associated with neuronal loss, astrocytosis and the presence in neurons of eosinophilic intracytoplasmic storage bodies with the characteristics of a lipopigment. In the retina there was progressive loss of photoreceptor cells. Storage bodies isolated from fresh brain, liver and pancreas formed electron-dense aggregates and coarse multilamellar and fine fingerprint profiles ultrastructurally, and consisted mainly of the hydrophobic protein, subunit c of mitochondrial ATP synthase. A homozygosity mapping approach localised the gene causing the disease in Merino sheep to the chromosomal region (OAR7q13-15) associated with NCL in South Hampshire sheep. Conclusion NCL in Merino sheep is a subunit c-storing disease, clinically and pathologically similar to NCL in South Hampshire sheep. We propose that the disease in both breeds represents mutation at the same gene locus in chromosomal region OAR7q13-15. [References: 26] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences CC - Veterinary Medicine/Animal Health in Current Contents(R)/Agricultural, Biology & Environmental Sciences. EW - 2002 week 24 IN - Reprint available from: Cook RW NSW Agr, Reg Vet Lab Wollongbar NSW 2477 Australia NSW Agr, Reg Vet Lab Wollongbar NSW 2477 Australia Massey Univ, Inst Vet Anim & Biomed Sci Palmerston North New Zealand Lincoln Univ, Anim & Food Sci Div Canterbury New Zealand Univ Sydney, Ctr Adv Technol Anim Genet & Reprod ReproGen, Dept Vet Clin Sci Camden NSW 2570 Australia Univ Otago, Dept Biochem Dunedin New Zealand Rural Lands Protect Board Tamworth NSW 2340 Australia <54> UI - 551ZY-0017 DD - ISI Document Solution: 551ZY AU - Mecocci P AU - Polidori MC AU - Cherubini A AU - Ingegni T AU - Mattioli P AU - Catani M AU - Rinaldi P AU - Cecchetti R AU - Stahl W AU - Senin U AU - Beal MF MA - mecocci@unipg.it RA - Mecocci P TI - Lymphocyte oxidative DNA damage and plasma antioxidants in Alzheimer disease SO - Archives of Neurology. 59(5):794-798, 2002 May. AS - Arch. Neurol 2002 May;59(5):794-798 PU - AMER MEDICAL ASSOC, 515 N STATE ST, CHICAGO, IL 60610 USA. URL: http://www.ama-assn.org IS - 0003-9942 MH - Central-nervous-system MH - C supplement use MH - Vitamin-c MH - Lipid-peroxidation MH - Cognitive function MH - Mitochondrial-dna MH - Stress MH - Carotenoids MH - Beta MH - Tissues. AB - Context: A large body of experimental evidence suggests that in Alzheimer disease (AD) pathogenesis an important role is played by oxidative stress, but there is still a lack of data on in vivo markers of free radical-induced damage. Objectives: To evaluate levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative damage to DNA, in peripheral lymphocytes; to measure plasma concentrations of several nonenzymatic antioxidants; and to assess the relationships between any observed changes in lymphocyte DNA 8-OHdG content and plasma antioxidant levels in patients with AD and healthy aged control subjects. Subjects: Forty elderly outpatients with AD and 39 healthy age- and sex-matched controls were studied. Main Outcome Measures: The level of 8-OHdG was determined in DNA extracted from lymphocytes and plasma levels of vitamin C, vitamin A, vitamin E, and carotenoids (zeaxanthin, beta-cryptoxanthin, lycopene, lutein, and alpha- and beta-carotene) were measured by high-performance liquid chromatography. Results: Lymphocyte DNA 8-OHdG content was significantly higher and plasma levels of antioxidants (with the exception of lutein) were significantly lower in patients with AD compared with controls, In patients with AD, a significant inverse relationship between lymphocyte DNA 8-OHdG content and plasma levels of lycopene, lutein, alpha-carotene, and beta-carotene, respectively, was observed. Conclusions: Markers of oxidative damage are increased in AD and correlate with decreased levels of plasma antioxidants. These findings suggest that lymphocyte DNA 8-OHdG content in patients with AD reflects a condition of increased oxidative stress related to a poor antioxidant status. [References: 54] LG - English PT - Article SB - Current Contents(R)/Clinical Medicine Current Contents(R)/Life Sciences CC - Neurology in Current Contents(R)/Clinical Medicine. Neurosciences & Behavior in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Mecocci P Univ Perugia, Inst Gerontol & Geriatr Via Eugubina 42 I-06122 Perugia Italy Univ Perugia, Inst Gerontol & Geriatr I-06122 Perugia Italy Univ Dusseldorf, Inst Physiol Chem D-4000 Dusseldorf Germany Cornell Univ, Dept Neurol & Neurosci, Weill Med Coll New York, NY USA Cornell Med Ctr, New York Hosp New York, NY USA <55> UI - 552BC-0011 DD - ISI Document Solution: 552BC AU - Thelen JJ AU - Ohlrogge JB MA - ohlrogge@pilot.msu.edu RA - Ohlrogge JB TI - The multisubunit acetyl-CoA carboxylase is strongly associated with the chloroplast envelope through non-ionic interactions to the carboxyltransferase subunits SO - Archives of Biochemistry & Biophysics. 400(2):245-257, 2002 Apr 15. AS - Arch. Biochem. Biophys 2002 Apr 15;400(2):245-257 PU - ACADEMIC PRESS INC ELSEVIER SCIENCE, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA. URL: http://www.apnet.com IS - 0003-9861 MH - Plants MH - Fatty acid synthesis MH - Plastids MH - Envelope membrane MH - Acetyl-coa carboxylase MH - Membrane association MH - Triton insoluble. MH - Coenzyme-a carboxylase MH - Fatty-acid synthesis MH - Carrier protein MH - Biotin carboxylase MH - Lipid biosynthesis MH - Spinacia-oleracea MH - Pisum-sativum MH - Dna-synthesis MH - Higher-plants MH - Membranes. AB - The committed step for de novo fatty acid biosynthesis is the carboxylation of acetyl-CoA catalyzed by acetyl-CoA carboxylase (ACCase). Plastidial ACCase from most plants is a multisubunit complex composed of multiple copies of four different polypeptides, biotin carboxyl carrier protein (BCCP), biotin carboxylase (BC), and carboxyltransferase (alpha-CT and beta-CT). Immunoblot analyses revealed these four proteins were mostly (69% of total) associated with a 17,000 g insoluble fraction from lysed pea chloroplasts. Under the same conditions only 8% of ribulose-1,5-bisphosphate carboxylase was associated with this insoluble fraction. BCCP and biotin carboxylase BC subunits freely dissociated from 17 kg insoluble fractions under high ionic strength conditions, whereas alpha-CT and beta-CT subunits remained tightly associated. Both CT subunits were highly enriched in envelope versus stroma and thylakoid preparations whereas BC and BCCP subunits were predominantly stromal-localized due to partial dissociation. Rapid solubilization of intact chloroplasts with Triton X-100 followed by centrifugation at 30 kg resulted in a pellet that was up to 8-fold enriched in ACCase activity and 21-fold enriched in BC activity. Triton-insoluble 30 kg pellets were reduced in lipid and chlorophyll content but enriched in chloroplast DNA due to the isolation of nucleoid particles. However, ACCase was not directly associated with nucleoids since enzymatic digestion of DNA or RNA had no effect on the association with Triton-in soluble matter. The amount of Triton-insoluble ACCase was similar in chloroplasts isolated from dark- or light-adaptated leaves suggesting transitory starch granules were also not involved in this association. It is proposed that ACCase is associated with envelope membranes through interactions with an unidentified integral membrane protein. (C) 2002 Elsevier Science (USA). All rights reserved. [References: 41] LG - English PT - Article SB - Current Contents(R)/Life Sciences CC - Biochemistry & Biophysics in Current Contents(R)/Life Sciences. EW - 2002 week 24 IN - Reprint available from: Ohlrogge JB Michigan State Univ, Dept Plant Biol E Lansing, MI 48824 USA Michigan State Univ, Dept Plant Biol E Lansing, MI 48824 USA