1 UI - 387UL-0022 AU - Zarco-Tejada PJ AU - Miller JR AU - Mohammed GH AU - Noland TL TI - Chlorophyll fluorescence effects on vegetation apparent reflectance: I. Leaf-level measurements and model simulation SO - Remote Sensing of Environment 2000 Dec;74(3):582-595 IS - 0034-4257 MH - Radiation-use-efficiency MH - Mediterranean trees MH - Pigment content MH - Spectra MH - Resolution MH - Physiology MH - Index AB - Results from a series of laboratory measurements of spectral reflectance and transmittance of individual leaves and from a modeling study are presented which demonstrate that effects of natural chlorophyll fluorescence (CF) are observable in the red edge spectral region. Measurements have been made with a Li-Cor Model 1800 integrating sphere apparatus coupled to an Ocean Optics Model ST1000 fiber spectrometer in which the same leaves are illuminated alternately with and without fluorescence-exciting radiation in order to separate the fluorescence emission component from the reflectance spectrum. The resulting difference spectrum is shown experimentally to be consistent with a fluorescence signature imposed on the inherent leaf reflectance signature. A study of the diurnal change in leaf reflectance spectra, combined with fluorescence measurements with the PAM-20000 Fluorometer, show that the difference spectra are consistent with observed diurnal changes in steady-state fluorescence. In addition, the time decay in the difference signature from repetitive leaf spectral reflectance measurements is seen to be consistent with the time decay of the leaf fluorescence signal (Kautsky effect) of dark-adapted leaves. The expected effects of chlorophyll fluorescence emission on the apparent spectral reflectance from a single leaf are also simulated theoretically using the doubling radiative transfer method. These modeling results demonstrate that the laboratory observations of a difference spectrum with broad peak at about 750 nm and a much smaller peak near 690 nm are in agreement with theory. Model simulation shows that chlorophyll pigment and fluorescence each affect indices that are being used in optical remote sensing to characterize pigment levels and stress in vegetation canopies. Implications for high spectral resolution remote sensing of forest canopies are presented in a companion paper. (C) 2000 Elsevier Science Inc. [References: 43] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences IN - Miller JR York Univ, Ctr Res Earth & Space Sci 4700 Keele St Toronto ON M3J 1PE Canada York Univ, Ctr Res Earth & Space Sci Toronto ON M3J 1PE Canada York Univ, Dept Phys & Astron Toronto ON M3J 2R7 Canada Ontario Minist Nat Resources, Ontario Forest Res Inst Sault Ste Marie ON Canada 2 UI - 387UL-0023 AU - Zarco-Tejada PJ AU - Miller JR AU - Mohammed GH AU - Noland TL AU - Sampson PH TI - Chlorophyll fluorescence effects on vegetation apparent reflectance: II. Laboratory and airborne canopy-level measurements with hyperspectral data SO - Remote Sensing of Environment 2000 Dec;74(3):596-608 IS - 0034-4257 MH - Spectral measurements MH - Mediterranean trees MH - Light-scattering MH - Pigment content MH - Red edge MH - Plants MH - Leaves MH - Field MH - Model MH - Photosynthesis AB - Relationships found between Compact Airborne Spectrographic Imager (CASI) hyperspectral canopy reflectance measurements at laboratory and field levels with PAM-2000 chlorophyll fluorescence data are presented. This is a continuation of the paper where relationships at the leaf level between leaf reflectance and chlorophyll fluorescence were found and demonstrated to the consistent with theory using the Fluorescence-Reflectance-Transmittance (FRT) model. Experiments using the hyperspectral CASI sensor in the laboratory to observe a canopy of maple seedlings are performed as an intermediate step to demonstrate the link between the results at leaf-level and the CASI field canopy levels. Scene observations of the seedling utilizing a long-pass blocking filter showed that apparent canopy reflectance in the laboratory is affected by changes in fluorescence emissions. A laboratory experiment on seedlings on seedlings subjected to diurnally induced change shows the strong link between CASI canopy reflectance optical indices in the 680-690-nm region and Fv/Vm dark-adapted chlorophyll fluorescence. Stressed and healthy maple seedlings are used to demonstrate the use of optical indices calculated from the 680-690-nm spectral region to track changes in steady-state fluorescence: the curvature index R6832/(R675-691) and the R685/R655 ratio calculated from the canopy reflectance are related to leaf-measured Ft, Fm' and DeltaF/Fm' steady-state features, and are in agreement with theoretical simulations using the leaf Fluorescence-Reflectance-Transmittance model. To test these findings in a field setting, airborne field hyperspectral CASI data of 2-m spatial resolution, 7.5-nm spectral resolution, and 72 channels was used, collected in deployments over 12 sites of Acer saccharum M. in the Algoma Region, Ontario (Canada) in 1997 and 1998. A field sampling campaign was carried out for biochemical contents of leaf chlorophyll and carotenoids, chlorophyll fluorescence, and leaf reflectance and transmittance. Leaf-level relationships obtained between optical indices and physiological indicators were scaled up to canopy level through canopy reflectance models using input model parameters related to the canopy structure and viewing geometry at the time of data acquisition. Results show that scaled-up optical indices in the 680-690-nm region are related to Fv/Fm chlorophyll fluorescence measured in the 20x20-m study sites. Consistency between leaf, laboratory, and field canopy hyperspectral data is shown in this and the previous paper, demonstrating the effect of fluorescence on observations of apparent vegetation reflectance. (C) Elsevier Science Inc., 2000. [References: 44] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences IN - Miller JR York Univ, Dept Phys & Astron 4700 Keele St Toronto ON M3J 1PE Canada York Univ, Dept Phys & Astron Toronto ON M3J 1PE Canada York Univ, Ctr Res Earth & Space Sci Toronto ON M3J 2R7 Canada Ontario Minist Nat Resources, Ontario Forest Res Inst Sault St Marie ON Canada 3 UI - 389DD-0016 AU - Omura S AU - Miyadera H AU - Ui H AU - Shiomi K AU - Yamaguchi Y AU - Masuma R AU - Nagamitsu T AU - Takano D AU - Sunazuka T AU - Harder A AU - Kolbl H AU - Namikoshi M AU - Miyoshi H AU - Sakamoto K AU - Kita K TI - An anthelmintic compound, nafuredin, shows selective inhibition of complex I in helminth mitochondria SO - Proceedings of the National Academy of Sciences of the United States of America 2001 Jan 2;98(1):60-62 IS - 0027-8424 MH - Fumarate reductase MH - Ascaris-suum MH - Respiratory-chain MH - Ubiquinone oxidoreductase MH - Parasitic nematode MH - Electron-transfer MH - Resistance MH - Subunit AB - Infections with parasitic helminths are important causes of morbidity and mortality worldwide. New drugs that are parasite specific and minimally toxic to the host are needed to counter these infections effectively. Here we report the finding of a previously unidentified compound, nafuredin, from Aspergillus niger. Nafuredin inhibits NADH-fumarate reductase (complexes I + II) activity, a unique anaerobic electron transport system in helminth mitochondria, at nM order. It competes for the quinone-binding site in complex I and shows high selective toxicity to the helminth enzyme. Moreover, nafuredin exerts anthelmintic activity against Haemonchus contortus in in vivo trials with sheep. Thus, our study indicates that mitochondrial complex I is a promising target for chemotherapy, and nafuredin is a potential lead compound as an anthelmintic isolated from microorganisms. [References: 26] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Omura S Kitasato Inst, Biol Funct Res Ctr, Minato Ku Tokyo 1088642 Japan Kitasato Inst, Biol Funct Res Ctr, Minato Ku Tokyo 1088642 Japan Univ Tokyo, Grad Sch Med, Dept Biomed Chem, Bunkyo Ku Tokyo 1130033 Japan Kitasato Univ, Sch Pharmaceut Sci, Minato Ku Tokyo 1088641 Japan Bayer AG, Biol Technol Ctr, Business Grp Anim Hlth D-51368 Leverkusen Germany Tokyo Univ Fisheries, Dept Ocean Sci, Minato Ku Tokyo 1088477 Japan Kyoto Univ, Grad Sch Agr, Div Appl Life Sci, Sakyo Ku Kyoto 6068502 Japan 4 UI - 389VF-0010 AU - Kim YH AU - Jeong DH AU - Kim D AU - Jeoung SC AU - Cho HS AU - Kim SK AU - Aratani N AU - Osuka A TI - Photophysical properties of long rodlike meso-meso-linked zinc(II) porphyrins investigated by time-resolved laser spectroscopic methods SO - Journal of the American Chemical Society 2001 Jan 10;123(1):76-86 IS - 0002-7863 MH - Photosynthetic reaction-center MH - Pump-probe spectroscopy MH - Resonance raman-spectra MH - Energy-transfer MH - Zn-tetraphenylporphyrin MH - Hybrid diporphyrins MH - Antenna complexes MH - Electron-transfer MH - Dimers MH - Arrays AB - The molecular design of directly meso-meso-linked porphyrin arrays as a new model of light-harvesting antenna as well as a molecular photonic wire was envisaged to bring the porphyrin units closer for rapid energy transfer. For this purpose, zinc(II) 5,15-bis(3,5-bis(octyloxy)phenyl)porphyrin (Z1) and its directly meso-meso-linked porphyrin arrays up to Z128 (Zn, n represents the number of porphyrins) were synthesized. The absorption spectra of these porphyrin arrays change in a systematic manner with an increase in the number of porphyrins; the high-energy Soret bands remain at nearly the same wavelength (413-414 nm), while the low-energy exciton split Soret bands are gradually red-shifted, resulting in a progressive increase in the exciton splitting energy. The exciton splitting is nicely correlated with the values of cos[pi/(N + 1)] according to Kasha's exciton coupling theory, providing a value of 4250 cm(-1) for the exciton coupling energy in the St state. The increasing red-shifts for the Q-bands are rather modest. The fluorescence excitation anisotropy spectra of the porphyrin arrays show that the photoexcitation of the high-energy Soret bands exhibits a large angle difference between absorption and emission dipoles in contrast with the photoexcitation of the low-energy exciton split Soret and Q-bands. This result indicates that the high-energy Soret bands are characteristic of the summation of the individual monomeric transitions with its overall dipole moment deviated from the array chain direction, while the low-energy Soret bands result from the exciton splitting between the monameric transition dipoles in line with the array chain direction. From the fluorescence quantum yields and fluorescence lifetime measurements, the radiative coherent length was estimated to be 6-8 porphyrin units in the porphyrin arrays. Ultrafast fluorescence decay measurements shaw that the S-2 --> S-1 internal conversion process occurs in less than 1 ps in the porphyrin arrays due to the existence of exciton split band as a ladder-type deactivation channel, while this process is relatively slow in Z1 (similar to1.6 ps). The rate of this process seems to follow the energy gap law, which is mainly determined by the energy gap between the two Soret bands of the porphyrin arrays. [References: 51] LG - English PT - Article SB - Current Contents(R)/Life Sciences Current Contents(R)/Physical, Chemical & Earth Sciences IN - Kim D Yonsei Univ, Dept Chem, Ctr Ultrafast Opt Characterist Control Seoul 120749 South Korea Yonsei Univ, Dept Chem, Ctr Ultrafast Opt Characterist Control Seoul 120749 South Korea Korea Res Inst Stand & Sci Taejon 305600 South Korea Seoul Natl Univ, Dept Chem Seoul 151742 South Korea Kyoto Univ, Grad Sch Sci, Dept Chem Kyoto 6068502 Japan 5 UI - 389VF-0013 AU - Imahori H AU - Norieda H AU - Yamada H AU - Nishimura Y AU - Yamazaki I AU - Sakata Y AU - Fukuzumi S TI - Light-harvesting and photocurrent generation by cold electrodes modified with mixed self-assembled monolayers of boron-dipyrrin and ferrocene-porphyrin-fullerene triad SO - Journal of the American Chemical Society 2001 Jan 10;123(1):100-110 IS - 0002-7863 MH - Charge separation MH - Artificial photosynthesis MH - Polycrystalline gold MH - Chain-length MH - Thin-films MH - Energy MH - Systems MH - Arrays MH - Photodimerization MH - Photochemistry AB - Three different kinds of mixed self-assembled monolayers have been prepared to mimic photosynthetic energy and electron transfer on a gold surface. Pyrene and boron-dipyrrin were chosen as a light-harvesting model. The mixed self-assembled monolayers of pyrene (or boron-dipyrrin) and porphyrin (energy acceptor model) reveal photoinduced singlet-singlet energy transfer from the pyrene (or boron-dipyrrin) to the porphyrin on the gold surface. The boron-dipyrrin has also been combined with a reaction center model, ferrocene-porphyrin-fullerene triad, to construct integrated artificial photosynthetic assemblies on a gold electrode using mixed monolayers of the respective self-assembled unit. The mixed self-assembled monolayers on the gold electrode have established a cascade of photoinduced energy transfer and multistep electron transfer, leading to the production of photocurrent output with the highest quantum yield (50 +/- 8%), based on the adsorbed photons ever reported for photocurrent generation at monolayer-modified metal electrodes and across artificial membranes using donor-acceptor linked molecules. The incident photon-to-current efficiency (IPCE) of the photoelectrochemical cell at 510 and 430 nm was determined as 0.6% and 1.6%, respectively. Thus, the present system provides the first example of an artificial photosynthetic system, which not only mimics light-harvesting and charge separation processes in photosynthesis but also acts as an efficient light-to-current converter in molecular devices. [References: 83] LG - English PT - Article SB - Current Contents(R)/Life Sciences Current Contents(R)/Physical, Chemical & Earth Sciences IN - Imahori H Osaka Univ, Japan Sci & Technol Corp, CREST, Grad Sch Engn,Dept Mat & Life Sci 2-2 Yamadaoka Suita Osaka 5650871 Japan Osaka Univ, Japan Sci & Technol Corp, CREST, Grad Sch Engn,Dept Mat & Life Sci Suita Osaka 5650871 Japan Hokkaido Univ, Grad Sch Engn, Dept Mol Chem Sapporo Hokkaido 0608628 Japan Osaka Univ, Inst Sci & Ind Res Ibaraki Osaka 5670047 Japan 6 UI - 387XN-0005 AU - Koniger M AU - Harris GC AU - Kibler E TI - Seasonal changes in the physiology of shade leaves of Acer saccharum SO - Journal of Plant Physiology 2000 Dec;157(6):627-636 IS - 0176-1617 MH - Acer saccharum MH - Photosynthesis MH - Pigments MH - Proteins MH - Psii MH - Leaf development MH - Photosynthetic electron-transport MH - Chlorophyll fluorescence MH - Leaf senescence MH - Differential changes MH - Rice seedlings MH - Gas-exchange MH - Nitrogen MH - Plants MH - Chloroplasts MH - Capacity AB - Changes in the physiology of shade leaves of sugar maple trees (Acer saccharum Marsh.) in eastern Massachusetts were monitored throughout several growing seasons. In the late spring, following leaf expansion, the sugar maple leaves showed high photosynthetic rates and a high carboxylation efficiency which increased only slightly into the early part of summer. in contrast, pigment and protein concentrations increased sharply from late spring to mid summer. The average photosynthetic rates remained fairly high during the summer and started to decrease in early September. This decrease was accompanied by decreases in leaf pigment, protein and nitrogen concentrations. In the last few weeks before leaf abscission photosynthesis was not limited by stomatal conductance as indicated by high internal CO2 concentrations. However, photosynthesis may have been CO2 limited at times during the summer. Low quantum yields of carbon fixation and low photosynthetic rates on some days during the summer indicated temporary stress. Experiments revealed that maple leaves responded to short-term stress by temporarily downregulating PSII. In general, leaves exhibited high Fv/Fm values throughout most of the year. Sustained photoinhibition as indicated by reduced Fv/Fm was only observed during the last few weeks before leaf abscission. Photochemical quenching remained high throughout the fall, indicating that the efficiency of excitation energy capture by open PSII reaction centers was the major reason for the decrease in photochemical efficiency of PSII during the last few weeks before the leaves were shed. At the same time the non-photochemical quenching increased throughout the fall and was only low in extremely yellow leaves. [References: 38] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences IN - Koniger M Wellesley Coll, Dept Biol Sci Wellesley, MA 02481 USA Wellesley Coll, Dept Biol Sci Wellesley, MA 02481 USA 7 UI - 387XN-0014 AU - Sherameti I AU - Oelmuller R TI - Newly synthesized PsbO is reversibly attached to the thylakoid membrane and released from the membrane under light stress SO - Journal of Plant Physiology 2000 Dec;157(6):699-706 IS - 0176-1617 MH - Oxygen-evolving complex MH - Photosystem ii MH - Psbo MH - 33 kda polypeptide MH - Tobacco MH - Manganese-stabilizing protein MH - Oxygen-evolving complex MH - 33-kda extrinsic protein MH - Photosystem-ii complex MH - Isolated-chloroplasts MH - Enzyme complex MH - Nuclear genes MH - D1 protein MH - Evolution MH - Binding AB - The 33 kDa protein (PsbO) is an important component of the photosystem II reaction center and located at the lumenal side of the thylakoid membrane. in vivo labelling assays of tobacco seedlings and subsequent immunoprecipitation of PsbO revealed that newly synthesized PsbO is present in the lumen as soluble and membrane-associated forms. The latter form appears to be associated with photosystem II. Since membrane association also occurs in darkness and in the presence of chloramphenicol, no newly-formed photosystem II particles are required. Comparable features with regard to the membrane association and membrane release of PsbO were obtained with an in vitro reconstitution system. In contrast to the D1 protein, the overall amount of PsbO does not change significantly under light stress; however, the polypeptide appears to be released from the membranes and accumulates in the thylakoid lumen. Re-association with the membrane does not occur under light-stress conditions. The conclusion is that membrane association of PsbO is sensitive to high light intensitites. [References: 43] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Life Sciences IN - Oelmuller R Univ Jena, Lehrstuhl Pflanzenphysiol, Inst Allgemeine Bot, Biol Pharmazeut Fak Dornburger Str 159 D-07743 Jena Germany Univ Jena, Lehrstuhl Pflanzenphysiol, Inst Allgemeine Bot, Biol Pharmazeut Fak D-07743 Jena Germany 8 UI - 389HE-0016 AU - Sagert S AU - Schubert H TI - Acclimation of Palmaria palmata (Rhodophyta) to light intensity: Comparison between artificial and natural light fields SO - Journal of Phycology 2000 Dec;36(6):1119-1128 IS - 0022-3646 MH - Acclimation MH - Field investigation MH - Light dose MH - Light intensity MH - Palmaria palmata MH - Photosynthesis MH - Pigmentation MH - Rhodophyta MH - Zonation MH - Alga porphyridium-cruentum MH - Term pigment response MH - Xanthophyll-cycle MH - Photosystem-ii MH - Phytoplankton photosynthesis MH - Chlorophyll fluorescence MH - Chromatic adaptation MH - Corallina-elongata MH - Growth irradiance MH - Chondrus-crispus AB - The acclimation of the photosynthetic apparatus of Palmaria palmata (L.) to light intensity was examined in the field and under laboratory conditions. Algae from 3 different shore levels and from laboratory cultures adapted to 6 different photon flux densities were compared. This was done on the basis of light doses, which were delivered by different light regimes in the field and in the laboratory. Laboratory samples were adjusted to constant photon flux densities between 7 and 569 mu mol photons(.)m(-2.)s(-1) in a 16:8 light:dark photoperiod, Under field conditions the daily amplitudes reached up to approximately 2000 mu mol photons(.)m(-2 .)s(-1) within a natural daily light course. Over the course of 14 days the light doses resulting from those different regimes are similar for both treatments, An increasing growth rate per day with increasing light doses was observed in the laboratory, Growth was saturated at 113 mol photons(.)m(-2) 14 d(-1). Light saturation points (E-k) of photosynthesis increased with increasing light doses for both field and laboratory samples, and all E-k values were significantly related to the growth light dose. A correlation between fresh weight-related lutein content and growth light dose was found for laboratory samples only, whereas the lutein:chlorophyll a (chl a) ratio was strongly correlated with E-k for laboratory and field samples, The content of chi a and phycoerythrin (PE) per fresh weight decreased significantly with increasing light doses under field conditions. Simultaneously, the PE:chl a ratio increased, whereas this ratio was not influenced by laboratory treatments. The correspondence of E-k values for field and laboratory treatments: indicated that they were affected mainly by light dose. However, the variability in pigmentation was mainly dependent on temporal variability in light intensity (the amplitude of variations in incident light). [References: 61] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences IN - Sagert S Univ Greifswald, Inst Ecol Grimmer Str 88 D-17487 Greifswald Germany Univ Greifswald, Inst Ecol D-17487 Greifswald Germany 9 UI - 388XR-0014 AU - Letelier RM AU - Karl DM AU - Abbott MR AU - Flament P AU - Freilich M AU - Lukas R AU - Strub T TI - Role of late winter mesoscale events in the biogeochemical variability of the upper water column of the North Pacific Subtropical Gyre SO - Journal of Geophysical Research-Oceans 2000 Dec 15;105(C12):28723-28739 IS - 0148-0227 MH - Central equatorial pacific MH - Sargasso sea MH - Phytoplankton community MH - Station aloha MH - Chlorophyll-a MH - Upper ocean MH - Photosynthesis MH - Fluorescence MH - Model MH - Productivity AB - Continuous records of upper water column (0-150 m) temperature profiles, spectral distribution of downwelling irradiance, and phytoplankton solar-induced fluorescence at 25 m depth were obtained during the inaugural deployment of the Hawaii Air-sea Logging Experiment, A Long-term Oligotrophic Habitat Assessment (HALE ALOHA) mooring, near the Hawaii Ocean Time-series (HOT) Station ALOHA (22 degrees 45'N; 158 degrees 00'W). The temperature record showed a strong upwelling event in March-April 1997, displacing the thermocline by 120 m. Remote sensing satellite (NSCAT and TOPEX/ERS 2) analyses suggest that the observed upwelling was a result of strong wind divergence and the passage of a cyclonic eddy through the HOT program study area, At the onset of the upwelling event increases in colored dissolved organic matter (CDOM) and chlorophyll fluorescence efficiency in the upper water column were detected by changes in the spectral distribution of the downwelling irradiance. The 0-25 m mean chlorophyll a (chl a) concentration increased threefold toward the end of the upwelling period. Water column samples collected during the monthly HOT cruises also indicate that the relative contribution of diatoms to total chi a increased twofold inside the eddy. The long-term temporal variability in frequency and intensity of these poorly resolved mesoscale events might be key factors determining the structure of the pelagic ecosystem in the North Pacific Subtropical Gyre. Integrating multi-year remote sensing satellite, moored, and vessel-based time series records permits a quantification of the spatial and temporal scale of upper water column perturbations and the characterization of the pelagic ecosystem response at various timescales. [References: 77] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences IN - Letelier RM Oregon State Univ, Coll Ocean & Atmospher Sci 104 Ocean Adm Bldg Corvallis, OR 97331 USA Oregon State Univ, Coll Ocean & Atmospher Sci Corvallis, OR 97331 USA Univ Hawaii, Sch Ocean & Earth Sci & Technol Honolulu, HI 96822 USA 10 UI - 388DB-0006 AU - Lisdiyanti P AU - Kawasaki H AU - Seki T AU - Yamada Y AU - Uchimura T AU - Komagata K TI - Systematic study of the genus Acetobacter with descriptions of Acetobacter indonesiensis sp nov., Acetobacter tropicalis sp nov., Acetobacter orleanensis (Henneberg 1906) comb. nov., Acetobacter lovaniensis (Frateur 1950) comb. nov., and Acetobacter estunensis (Carr 1958) comb. nov. SO - Journal of General & Applied Microbiology 2000 Jun;46(3):147-165 IS - 0022-1260 MH - Acetobacter aceti MH - Acetobacter estunensis MH - Acetobacter indonesiensis MH - Acetobacter lovaniensis MH - Acetobacter orleanensis MH - Acetobacter pasteurianus MH - Acetobacter peroxydans MH - Acetobacter tropicalis MH - Acetic-acid bacteria MH - Dna-base composition MH - Allied organisms MH - Ribosomal-rna MH - Relatedness MH - Sequences MH - Strains MH - Xylinus AB - Thirty-one Acetobacter strains obtained from culture collections and 45 Acetobacter strains isolated from Indonesian sources were investigated for their phenotypic characteristics, ubiquinone systems, DNA base compositions, and levels of DNA-DNA relatedness. Of 31 reference strains, six showed the presence of ubiquinone 10 (Q-10). These strains were eliminated from the genus Acetobacter. The other 25 reference strains and 45 Indonesian isolates were subjected to a systematic study and separated into 8 distinct groups on the basis of DNA-DNA relatedness. The known species, Acetobacter aceti, A. pasteurianus, and A. peroxydans are retained for three of these groups. New combinations, A. orleanensis (Henneberg 1906) comb. nov., A. lovaniensis (Frateur 1950) comb. nov., and A. estunensis (Carr 1958) comb. nov. are proposed for three other groups. Two new species, A. indonesiensis sp. nov. and A. tropicalis sp. nov. are proposed for the remaining two. No Indonesian isolates were identified as A. aceti, A. estunensis, and A. peroxydans. Phylogenetic analysis on the basis of 16S rDNA sequences was carried out for representative strains from each of the groups. This supported that the eight species belonged to the genus Acetobacter. Several strains previously assigned to the species of A. aceti and A. pasteurianus were scattered over the different species. It is evident that the value of DNA-DNA relatedness between strains comprising a new species should be determined for the establishment of the species. Thus current bacterial species without data of DNA-DNA relatedness should be reexamined for the stability of bacterial nomenclature. [References: 44] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Lisdiyanti P Tokyo Univ Agr, Fac Appl Biosci, Dept Appl Biol & Chem, Lab Gen & Appl Microbiol,Setagaya Ku Tokyo 1568502 Japan Tokyo Univ Agr, Fac Appl Biosci, Dept Appl Biol & Chem, Lab Gen & Appl Microbiol,Setagaya Ku Tokyo 1568502 Japan Osaka Univ, Int Ctr Biotechnol Suita Osaka 5650871 Japan 11 UI - 388ZM-0010 AU - Kumar ATN AU - Rosca F AU - Widom A AU - Champion PM TI - Investigations of amplitude and phase excitation profiles in femtosecond coherence spectroscopy SO - Journal of Chemical Physics 2001 Jan 8;114(2):701-724 IS - 0021-9606 MH - Pump-probe spectroscopy MH - Stimulated light-scattering MH - Dynamic absorption-spectra MH - Electronic ground-state MH - Impulsive excitation MH - Vibrational motion MH - Nuclear motion MH - Heme-proteins MH - Line-shapes MH - Rhodobacter-sphaeroides AB - We present an effective linear response approach to pump-probe femtosecond coherence spectroscopy in the well-separated pulse limit. The treatment presented here is based on a displaced and squeezed state representation for the nonstationary states induced by an ultrashort pump laser pulse or a chemical reaction. The subsequent response of the system to a delayed probe pulse is modeled using closed form nonstationary linear response functions, valid for a multimode vibronically coupled system at arbitrary temperature. When pump-probe signals are simulated using the linear response functions, with the mean nuclear positions and momenta obtained from a rigorous moment analysis of the pump induced (doorway) state, the signals are found to be in excellent agreement with the conventional third-order response approach. The key advantages offered by the moment analysis-based linear response approach include a clear physical interpretation of the amplitude and phase of oscillatory pump-probe signals, a dramatic improvement in computation times, a direct connection between pump-probe signals and equilibrium absorption and dispersion lineshapes, and the ability to incorporate coherence associated with rapid nonradiative surface crossing. We demonstrate these aspects using numerical simulations, and also apply the present approach to the interpretation of experimental amplitude and phase measurements on reactive and nonreactive samples of the heme protein myoglobin. The role played by inhomogeneous broadening in the observed amplitude and phase profiles is discussed in detail. We also investigate overtone signals in the context of reaction driven coherent motion. (C) 2001 American Institute of Physics. [References: 78] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences IN - Kumar ATN Northeastern Univ, Dept Phys Boston, MA 02115 USA Northeastern Univ, Dept Phys Boston, MA 02115 USA Northeastern Univ, Ctr Interdisciplinary Res Complex Syst Boston, MA 02115 USA 12 UI - 390DP-0015 AU - He QF AU - Dolganov N AU - Bjorkman O AU - Grossman AR TI - The high light-inducible polypeptides in Synechocystis PCC6803 - Expression and function in high light SO - Journal of Biological Chemistry 2001 Jan 5;276(1):306-314 IS - 0021-9258 MH - Iron superoxide-dismutase MH - Membrane-protein damage MH - Photosystem-ii MH - Xanthophyll cycle MH - In-vivo MH - Chloroplast membranes MH - Nucleotide-sequence MH - Excitation-energy MH - Stress MH - Plants AB - There are five Synechocystis PCC6803 genes encoding polypeptides with similarity to the Lhc polypeptides of plants. Four of the polypeptides, designated HliA-D (Dolganov, N. A M., Bhaya, D., and Grossman, A. R. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 636-640) (corresponding to ScpC, ScpD, ScpB, and ScpE in Funk, C., and Vermaas, W. (1999) Biochemistry 38, 9397-9404) contain a single transmembrane domain. The fifth polypeptide (HemH) represents a fusion between a ferrochelatase and an Hli-like polypeptide. By using an epitope tag to identify specifically the different Hli polypeptides, the accumulation of each (excluding HemH) was examined under various environmental conditions. The levels of all of the Hli polypeptides were elevated in high light and during nitrogen limitation, whereas HliA, HliB, and HliC also accumulated to high levels following exposure to sulfur deprivation and low temperature. The temporal pattern of accumulation was significantly different among the different Hli polypeptides. HliC rapidly accumulated in high light, and its level remained high for at least 24 h. HliA and HliB also accumulated rapidly, but their levels began to decline 9-12 h following the imposition of high light. HliD was transiently expressed in high light and was not detected 24 h after the initiation of high light exposure. These results demonstrate that there is specificity to the accumulation of the Hli polypeptides under a diverse range of environmental conditions. Furthermore, mutants for the individual and combinations of the hli genes were evaluated for their fitness to grow in high light. Although all of the mutants grew as fast as wild-type cells in low light, strains inactivated for hliA or hliC/hliD were unable to compete with wild-type cells during co-cultivation in high light. A mutant lacking all four hli genes gradually lost its photosynthesis capacity and died in high light. Hence, the Hli polypeptides are critical for survival when Synechocystis PCC6803 is absorbing excess excitation energy and may allow the cells to cope more effectively with the production of reactive oxygen species. [References: 79] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - He QF Carnegie Inst Washington, Dept Plant Biol 290 Panama St Stanford, CA 94305 USA Carnegie Inst Washington, Dept Plant Biol Stanford, CA 94305 USA Stanford Univ, Sch Med, Dept Microbiol & Immunol Stanford, CA 94305 USA 13 UI - 390DP-0060 AU - Kruk J AU - Strzalka K TI - Redox changes of cytochrome b(559) in the presence of plastoquinones SO - Journal of Biological Chemistry 2001 Jan 5;276(1):86-91 IS - 0021-9258 MH - Ii reaction center MH - Alpha-tocopherol quinone MH - Electron-transport properties MH - Charge-transfer complexes MH - Photosystem-ii MH - Oxygen evolution MH - Photoinhibition MH - Particles MH - Plants AB - We have found that short chain plastoquinones effectively stimulated photoreduction of the low potential form of cytochrome b(559) and were also active in dark oxidation of this cytochrome under anaerobic conditions in Triton X-100-solubilized photosystem II (PSII) particles. It is also shown that molecular oxygen competes considerably with the prenylquinones in cytochrome b(559) oxidation under aerobic conditions, indicating that both molecular oxygen and plastoquinones could be electron accepters from cytochrome b(559) in PSII preparations. alpha -Tocopherol quinone was not active in the stimulation of cytochrome photoreduction but efficiently oxidized it in the dark. Both the observed photoreduction and dark oxidation of the cytochrome were not sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea. It was concluded that both quinone-binding sites responsible for the redox changes of cytochrome b(559) are different from either the Q(A) or Q(B) site in PSII and represent new quinone-binding sites in PSII. [References: 31] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Strzalka K Jagiellonian Univ, Jan Zurzycki Inst Mol Biol, Dept Plant Physiol & Biochem Aleja Mickiewicza 3 PL-31120 Krakow Poland Jagiellonian Univ, Jan Zurzycki Inst Mol Biol, Dept Plant Physiol & Biochem PL-31120 Krakow Poland 14 UI - 388LE-0026 AU - Forney CF AU - Jordan MA AU - Nicholas KUKG AU - DeEll JR TI - Volatile emissions and chlorophyll fluorescence as indicators of freezing injury in apple fruit SO - Hortscience 2000 Dec;35(7):1283-1287 IS - 0018-5345 MH - Ethanol MH - Ethyl acetate MH - Ethylene MH - Respiration MH - Firmness MH - Browning MH - Malus xdomestica MH - Stress MH - Acetaldehyde MH - Atmospheres MH - Induction MH - Ethanol AB - Use of volatile emissions and chlorophyll fluorescence as indicators of freezing injury were investigated for apple fruit (Malus xdomestica Borkh.). 'Northern Spy' and 'Delicious' apples were kept at -8.5 degreesC far 0, 6, or 24 h, and then at 20 degreesC. After 1, 2, 5, and 7 d at 20 degreesC, fruit were analyzed for firmness, skin and flesh browning, soluble solid content, titratable acidity, ethanol, ethyl acetate, ethylene, respiration rate, and chlorophyll fluorescence. Freezing caused skin and flesh browning and a loss of fruit firmness, which was greater in 'Northern Spy' than in 'Delicious'. In 'Northern Spy' fruit subjected to the freezing treatments, ethanol and ethyl acetate concentrations mere as much as 37- and 300- fold greater, respectively, than in control fruit. 'Delicious' fruit showed similar patterns of ethanol and ethyl acetate increase, but of lower magnitude, as a result of freezing. Higher fruit respiratory quotients were associated with increased ethanol and ethyl acetate concentrations. Ethylene production and chlorophyll fluorescence of fruit were reduced by freezing. [References: 26] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences IN - Forney CF Agr & Agri Food Canada, Atlantic Food & Hort Res Ctr 32 Main St Kentville NS B4N 1J5 Canada Agr & Agri Food Canada, Atlantic Food & Hort Res Ctr Kentville NS B4N 1J5 Canada Agr & Agri Food Canada, Hort Res & Dev Ctr St Jean PQ J3B 3E6 Canada 15 UI - 390HJ-0002 AU - Krieger-Liszkay A AU - Kienzler K AU - Johnson GN TI - Inhibition of electron transport at the cytochrome b(6)f complex protects photosystem II from photoinhibition SO - FEBS Letters 2000 Dec 15;486(3):191-194 IS - 0014-5793 MH - Photoinhibition MH - 2 ' iodo-6-isopropyl-3-methyl-2 ',4,4 '-trinitrodiphenylether MH - Reactive oxygen species MH - D1 protein MH - In-vivo MH - Degradation MH - Mechanism MH - Photosynthesis MH - Chloroplasts MH - Inactivation MH - Chlorophyll MH - Acceptor MH - Fluorescence AB - Photoinhibition of photosystem II (PS II) activity was studied in thylakoid membranes illuminated in the presence of the inhibitor of the cytochrome b(6)f complex 2'iodo-6-isopropyl-3-methyl-2',4,4'-trinitrodiphenylether (DNP-INT), DNP-INT was found to decrease photoinhibition. In the absence of DNP-INT, anaerobosis, superoxide dismutase and catalase protected against photoinhibition. No effect of these treatments was observed in the presence of DNP-INT. These data demonstrate that photoinhibition under these conditions is caused by reactive oxygen species which are formed most probably by the reduction of oxygen at photosystem I. The results are discussed in terms of the importance of photosynthetic control in protection against photoinhibition in vivo. (C) 2000 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 IN - Johnson GN Univ Manchester, Sch Biol Sci 3-614 Stopford Bldg,Oxford Rd Manchester M13 9PT Lancs England Univ Manchester, Sch Biol Sci Manchester M13 9PT Lancs England Univ Freiburg, Inst Biol 2 D-79104 Freiburg Germany 16 UI - 390HJ-0012 AU - Schoefs B AU - Bertrand M TI - The formation of chlorophyll from chlorophyllide in leaves containing proplastids is a four-step process SO - FEBS Letters 2000 Dec 15;486(3):243-246 IS - 0014-5793 MH - Pigment biosynthesis MH - Hplc MH - Greening MH - Chlorophyll MH - Esterification MH - Last step of the chlorophyll biosynthetic pathway MH - Prolamellar bodies MH - Bean-leaves MH - Photosynthetic pigments MH - Photosystem-ii MH - Dark MH - Protochlorophyllide MH - Photoreduction MH - Precursors MH - Synthetase MH - Phytol AB - The time course of the different esters of chlorophyllide (Chlide) during the formation of chlorophyll a (Chl) in embryonic bean leaves containing proplastids was investigated by HPLC. After the reduction of photoactive Pchlide (Pchlide) to Chlide, three intermediates, i.e. Chlide geranylgeraniol, Chlide dihydrogeranylgeraniol and Chlide tetrahydrogeranylgeraniol were detected before the formation of Chlide phytol, i.e. authentic Chl. The transformation of Chlide to Chl was found to be much faster in leaves containing proplastids than in etiolated leaves with etioplasts. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. [References: 41] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Bertrand M Conservatoire Natl Arts & Metiers, Inst Natl Sci & Tech Mer Digue Collignon F-50110 Tourlaville France Conservatoire Natl Arts & Metiers, Inst Natl Sci & Tech Mer F-50110 Tourlaville France Univ S Bohemia, Lab Biomembranes CZ-37005 Ceske Budejovice Czech Republic 17 UI - 390HJ-0023 AU - Carrozzo R AU - Murray J AU - Santorelli FM AU - Capaldi RA TI - The T9176G mutation of human mtDNA gives a fully assembled but inactive ATP synthase when modeled in Escherichia coli SO - FEBS Letters 2000 Dec 15;486(3):297-299 IS - 0014-5793 MH - F1f0 atp synthase MH - Mitochondrial MH - Subunit 6 MH - T8993g MH - Escherichia coli MH - Bilateral striatal necrosis MH - Mitochondrial-dna MH - Atpase-6 gene MH - Epsilon-subunit MH - Point mutation MH - F1 AB - A new mutation in human F1F0 ATPase6 T9176G, which changes Leu 217 to an Arg, has been described in two siblings with Leigh syndrome [Carrozzo et al. (2000) Neurology, in press]. This mutation was modeled in Escherichia coli by changing Leu 259 (the equivalent residue) to Arg and the properties of the altered ECF1F0 were compared to those of previously characterized ATPase6 mutants also modeled in the E. coli enzyme. The L259R change produced a fully assembled ECF1F0 which had no significant ATP hydrolysis, ATP synthesis or proton pumping functions. This is very different from previously described human ATPase6 mutations. The presence of Arg at position 259 in subunit a did not make membranes permeable to protons. We conclude that the mutation inhibits functioning by blocking the rotary motor action of the enzyme. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. [References: 23] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Capaldi RA Univ Oregon, Inst Mol Biol Eugene, OR 97403 USA Univ Oregon, Inst Mol Biol Eugene, OR 97403 USA Osped Pediat Bambino Gesu, Mol Med Unit I-00165 Rome Italy 18 UI - 390EA-0006 AU - Silva JE TI - Uncoupling proteins 2 and 3 and their potential role in human obesity [Review] SO - Drug Development Research 2000 Oct;51(2):112-123 IS - 0272-4391 MH - Energy metabolism MH - Thermogenesis MH - Mitochondria MH - Mitochondrial proteins MH - Oxidative phosphorylation MH - Lipid metabolism MH - Resting metabolic-rate MH - Messenger-rna expression MH - White adipose-tissue MH - Diabetic fatty rats MH - Ob gene-expression MH - Body-mass index MH - Skeletal-muscle MH - Thyroid-hormone MH - Energy-metabolism MH - Up-regulation AB - The recently cloned uncoupling proteins 2 and 3 (UCP2, UCP3) cDNAs encode for proteins with 57-59% homology with brown adipose tissue uncoupling protein (UCP1). As this latter, the novel UCPs can reduce the proton motive force across the inner membrane of the mitochondria, but whether or not they function as uncouplers under physiological conditions has not been unequivocally confirmed. Low resting energy expenditure and difficulty oxidizing fat are potential risk factors for the development of obesity, and they could potentially be affected by the novel UCPs. However, studies largely focused on gene expression regulation do not support a role for the level of expression of these proteins in determining energy balance. Overall, the information available suggests more complexity than anticipated and many of the observations are hard to reconcile with a simple role for these proteins in energy dissipation. The possibility that these proteins, particularly the ubiquitous UCP2, have unsuspected functions, some of them cell-specific, remains open. One such function could be the reduction of the formation of reactive oxygen species during mitochondrial respiration. It is necessary to define the physiological role of these proteins in the cell and how their activity is regulated. Only when this information is available will we be in a position to determine whether they could be the targets for pharmacological intervention in the treatment or prevention of obesity, and perhaps to influence other metabolic processes. (C) 2000 Wiley-Liss, Inc. [References: 101] LG - English PT - Review SB - Current Contents(R)/Life Sciences IN - Silva JE Jewish Gen Hosp, Div Endocrinol, Dept Med Room E-162,3755 Chemin Cote Ste Catherine Montreal PQ H3T 1E2 Canada Jewish Gen Hosp, Div Endocrinol, Dept Med Montreal PQ H3T 1E2 Canada Jewish Gen Hosp, Lady Davis Inst Med Res Montreal PQ H3T 1E2 Canada McGill Univ Montreal PQ Canada 19 UI - 388VV-0008 AU - Gibb SW AU - Cummings DG AU - Irigoien X AU - Barlow RG AU - Fauzi R AU - Mantoura C TI - Phytoplankton pigment chemotaxonomy of the northeastern Atlantic SO - Deep-Sea Research Part II-Topical Studies in Oceanography 2001;48(4-5):795-823 IS - 0967-0645 MH - Subtropical north-atlantic MH - Coccolithophore bloom MH - Marine-phytoplankton MH - Chlorophyll maximum MH - Community structure MH - Mediterranean-sea MH - Euphotic zone MH - Ocean MH - Hplc MH - Carbon AB - Phytoplankton pigment distributions were studied between 62 and 37 degreesN in the northeastern Atlantic as a component of the NERC PRIME programme. At the northern end of the transect, waters were characterised by a surface chlorophyll a (CHLa) maximum of 500-700 ng l(-1) (0-40 mj. At the southern end, surface waters were virtually devoid of nutrients (NO3- < 0.5 M, NH4+ < 50 nM), and surface CHLa concentrations were < 50 ng l(-1). At 37 degreesN a well-defined deep CHLa maximum (DCM) was recorded between 60 and 100 m (similar to 350 ng l(-1)). Highest concentrations of CHLa (1500 mug l(-1)) were measured in the surface mixed layer to the south of a. well-defined salinity and temperature front at 52.5 degreesN. Overall, 19'-hexanoyloxyfucoxanthin (HEX, up to 1120 ng l(-1)) was the dominant accessory pigment, although zeaxanthin (ZEA) was the major accessory pigment at 37 degreesN. Conversion of pigment data into quantitative estimates of algal class abundances indicated the composition of phytoplankton population was relatively stable in surface waters between 62 and 52.5 degreesN: Prymnesiophytes were the most abundant class, contributing a mean of 38% of the total CHLa, while cryptophytes (20%), chlorophytes (14%) and diatoms (15 %) contributed the bulk of the remaining CHLa. Together, these four classes accounted for 79-92% of the total CHLa in this section of the transect. Immediately south of the front (52-50 degreesN), prymnesiophytes contributed approximately half of the total CHLa, while south of 50 degreesN there was a shift to a population dominated by cyanobacteria and prochlorophytes, which together accounted for a mean of 53% of the measured total CHLa at 37 degreesN. At 37 degreesN the contribution of cyanobacteria to total CHLa declined significantly with depth, and the DCM was dominated by prochlorophytes, prymnesiophytes and cryptophytes. Below the DCM, chrysophytes were the most abundant class of phytoplankton, contributing 30% of the total CHLa, with prymnesiophytes, prochlorophytes and cryptophytes also making significant contributions. The contribution of prymnesiophytes to total CHLa was found to be relatively stable throughout the water column (23%, SD 3 %). Although highest concentrations of divinyl chlorophyll n (dvCHLa) were recorded in the DCM, the contribution of dvCHLa to total CHLa (dvCHLa + CHLa) was only 21-26% here compared to up to 48% (mean = 33 +/- 9.6%) in surface waters. The ratio of [dvCHLa]: prochlorophyte biomass increased from 10 ng mug C-1 in the surface 40 M to 56.9 ng mug C-1 between 50 and 100 m. This corresponded to a rise in cellular dvCHLa from 0.215 to 1.83 mug cell(-1) and thus significant photo-adaptation with depth. Hence, a component of the DCM fluorescence and pigment signals is the result of increased cellular pigmentation rather than from increases in biomass alone. On the basis of inter-pigment ratios, we suggest that the DCM was dominated by an Atlantic strain of prochlorophytes, adapted to lower light levels, while the surface oligotrophic layer was composed of a mixed population of both Atlantic and a higher light adapted Mediterranean strain. Correlation studies indicated the potential of CHLa, fucoxanthin (FUC) and HEX to serve as respective proxy markers of POC and the biominerals silicate (SiO2) and calcite (CaCO3) in surface waters (r = 0.49-0.78, p < 0.001) and in depth profiles at northern latitudes (59N, r = 0.74-0.75, p < 0.001). However, poor correlations were observed in depth profiles at the southern end of the transect. (C) 2001 Published by Elsevier Science Ltd. [References: 53] LG - English PT - Article SB - Current Contents(R)/Agriculture, Biology & Environmental Sciences Current Contents(R)/Physical, Chemical & Earth Sciences IN - Gibb SW Univ Highlands & Isl, N Highland Coll, ERI Castle St Thurso Caithness Scotland Plymouth Marine Lab Plymouth PL1 3DH Devon England 20 UI - 389JV-0009 AU - Pasimeni L AU - Ruzzi M AU - Prato M AU - Da Ros T AU - Barbarella G AU - Zambianchi M TI - Spin correlated radical ion pairs generated by photoinduced electron transfer in composites of sexithiophene/fullerene derivatives: a transient EPR study SO - Chemical Physics 2001 Jan 1;263(1):83-94 IS - 0301-0104 MH - Sexithiophene/fullerene composites MH - Photoinduced electron transfer MH - Spin correlated radical ion pairs MH - Transient epr spectroscopy MH - Photosynthetic reaction centers MH - Bacterial reaction centers MH - Paramagnetic-resonance MH - Triplet-state MH - Photosystem-i MH - Fullerene derivatives MH - Polymers MH - Photoexcitations MH - Polarization MH - Resolution AB - Photoinduced electron transfer was observed in a series of methylsulfanyl sexithiophene/fulleropyrrolidine composites deposited as films. Paramagnetic states were observed by transient EPR spectroscopy in the microseconds time domain. The spectra displayed polarized lines with characteristic antiphase emission/absorption pattern of spin polarization and were assigned to spin correlated radical ion pairs (SCRP) formed by intermolecular electron transfer from sexithiophene donor to C-60 fullerene acceptor molecules. Also transient signals detected at selected magnetic fields showed phase effects that are typical of SCRPs, Spectrum simulation was obtained by allowing for a distribution of respective orientations of the dipolar axes and g-tensors of partners in a pair. Fitting parameters used for one composite were D/g beta = -135 muT and J/g beta = 2.5 muT for dipolar and spin exchange coupling constants, corresponding to an interradical mean distance of 27.4 Angstrom. Similar values were obtained for the other examined systems. Pair structure and dynamics suggest to ascribe the charge-separated state to a radical pair generated after a hopping of the electron-hole charges from a primary pair originated in neighbor molecular sites. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 43] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences IN - Pasimeni L Univ Padua, Dept Chem Phys Via Loredan 2 I-35131 Padua Italy Univ Padua, Dept Chem Phys I-35131 Padua Italy Univ Trieste, Dept Pharmaceut Sci I-34127 Trieste Italy CNR, Area Ric, ICo CEA I-40129 Bologna Italy 21 UI - 388TY-0004 AU - Minami N AU - Sasaki K AU - Aizawa A AU - Miyamoto M AU - Imai H TI - Analysis of gene expression in mouse 2-cell embryos using fluorescein differential display: Comparison of culture environments SO - Biology of Reproduction 2001 Jan;64(1):30-35 IS - 0006-3363 MH - Gametogenesis MH - Implantation/early development MH - Nuclear autoantigenic protein MH - Translation initiation-factor MH - One-cell embryos MH - Messenger-rna MH - In-vitro MH - Saccharomyces-cerevisiae MH - Mammalian development MH - Histone-binding MH - Major products MH - Xenopus-laevis AB - The effect of the oviductal environment on gene expression in 2-cell mouse embryos was examined with mRNA differential display. Embryos used for experiments were cultured in modified Whitten medium with or without oviductal tissue until late 2-cell stage. The results of sequencing indicated that the genes for ATP synthase (ATPase 6), S-adenosylmethionine decarboxylase (S-AMDC) and nuclear autoantigenic sperm protein (NASP) were differentially expressed in embryos cultured in the oviductal environment (nonblocking culture condition). The ATPase 6 gene is encoded by mitochondrial DNA and is essential for the production of ATP. This indicates that the expression of ATP synthesis-related genes at the 2-cell stage may be required to maintain normal development in vitro. S-Adenosylmethionine decarboxylase decarboxylates adenosylmethionine, which is a substrate of DNA methylation. The expression of S-AMDC may be responsible for the low level of methylation of preimplantation development. As NASP is a histone-binding protein that is thought to be testis and sperm specific, its function in embryos remains unclear. On the other hand, the Tell gene and a novel gene, the c-1 gene, were strongly expressed in embryos cultured without oviductal tissue (blocking culture condition). The expression patterns of these genes are quite similar. However, the detailed functions of these genes in embryos remain to be determined. [References: 50] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Minami N Kyoto Univ, Grad Sch Agr, Reprod Physiol Lab Kyoto 6068502 Japan Kyoto Univ, Grad Sch Agr, Reprod Physiol Lab Kyoto 6068502 Japan Livestock Improvement Assoc JAPAN Inc, Maebashi Inst Anim Sci Maebashi Gumma 3710121 Japan 22 UI - 389PE-0005 AU - Bagramyan K AU - Vassilian A AU - Mnatsakanyan N AU - Trchounian A TI - Participation of hydrogenase 4, encoded by hyf operon, in liberation of molecular hydrogen and proton-potassium exchange by Escherichia coli [Russian] SO - Biologicheskie Membrany 2000 Nov-Dec;17(6):604-615 IS - 0233-4755 MH - Formate-hydrogenlyase MH - Nucleotide-sequence MH - Direct transduction MH - Large subunit MH - Atp-synthase MH - System MH - Lyase MH - Transport MH - Ph MH - Fermentation AB - An interplay between production of H-2 and H+-K+-exchange with stable stoichiometry of N,N'-dicyclohexylcarbodiimide.(DCC)-inhibited ion fluxes that is equal to 2H(+)/K+ under different external pH and Kt activity has been established for fermenting Escherichia coli grown under anaerobic conditions at pH 7.5 (Trchounian et al./ Biol. Membrany. 1999. V. 16. P. 416-428 (Russian)). In the present study, the production of H-2 was observed in fermenting bacteria grown at pH 7.5 or 6.5 and inhibited by DCC. H-2 production was absent when bacteria were grown at pH 7.5 in the medium containing formate or upon hypo-osmotic stress. It had no sensitivity to osmotic stress when bacteria were grown at pH 6.5. Formation of H-2 and 2H(+)/K+-exchange were not observed in mutants with deletions:of hyf operon genes, encoding membrane-associated hydrogenase 4. Unlike parental strain, valinomycin had no effect on K+ influx by these mutants. When bacteria were grown at pH 6.5 and upon hyper-osmotic stress, these mutants produced HL, and carried out 2H(+)/K+-exchange. Participation of hydrogenase 4 in the production of H-2 and proton-potassium exchange by fermenting E. coli grown at pH 7.5 is suggested. It is possible that the other hydrogenase - hydrogenase 3, is responsible for the production of H-2, when bacteria were grown at pH 6.5 or in the medium containing formate. [References: 29] LG - Russian PT - Article SB - Current Contents(R)/Life Sciences IN - Bagramyan K Yerevan State Univ, Fac Biol, Dept Biophys Yerevan 375049 Armenia Yerevan State Univ, Fac Biol, Dept Biophys Yerevan 375049 Armenia Yerevan State Univ, Fac Biol, Dept Biochem Yerevan 375049 Armenia 23 UI - 388JT-0014 AU - Ducarme P AU - Thomas A AU - Brasseur R TI - The optimisation of the helix/helix interaction of a transmembrane dimer is improved by the IMPALA restraint field SO - Biochimica et Biophysica Acta - Biomembranes 2000 Dec 20;1509(1-2):148-154 IS - 0005-2736 MH - Membrane MH - Protein MH - Structure MH - Prediction MH - Hydrophobicity MH - Computer MH - Glycophorin MH - Light-harvesting complexes MH - Membrane-protein MH - Escherichia-coli MH - Reconstitution AB - A continuous membrane model (IMPALA) was previously developed to predict how hydrophobic spans of proteins insert in membranes (Mol. Mod. 2 (1996) 27). Using that membrane model, we looked for the interactions between several hydrophobic spans. We used the glycophorin A dimer as an archetype of polytopic protein to validate the approach. We find that the native complex do not dislocate when it is submitted to a 10(5) steps optimisation whereas separated spans converge back to a native-like complex in the same conditions. We also observe that IMPALA restraints are not strictly mandatory but do increase the efficiency of the procedure. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 17] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Brasseur R Univ Gembloux, Fac Sci Agron Gembloux, Ctr Biophys Mol Numer Passage Deportes 2 B-5030 Gembloux Belgium Univ Gembloux, Fac Sci Agron Gembloux, Ctr Biophys Mol Numer B-5030 Gembloux Belgium INSERM U410, IFR Bichat 10 F-75018 Paris France 24 UI - 388JT-0021 AU - Okulski W AU - Sujak A AU - Gruszecki WI TI - Dipalmitoylphosphatidylcholine membranes modified with zeaxanthin: numeric study of membrane organisation SO - Biochimica et Biophysica Acta - Biomembranes 2000 Dec 20;1509(1-2):216-228 IS - 0005-2736 MH - Carotenoid MH - Xanthophyll pigment MH - Lipid membrane MH - Monte carlo simulation MH - Molecular aggregate MH - Beta-carotene MH - Lipid-membranes MH - Monte-carlo MH - Phosphatidylcholine liposomes MH - Phospholipid-vesicles MH - Phase-transitions MH - Lateral diffusion MH - Polar carotenoids MH - Spin-label MH - Bilayers AB - The model of a dipalmitoylphosphatidylcholine (DPPC) bilayer containing a xanthophyll pigment zeaxanthin (ZEA) is proposed. The model is based on the ten-state Pink-Green-Chapman model of a lipid monolayer. The Monte Carlo method of computer simulation has been applied. Our model of the lipid membrane consists of two lipid monolayers with ZEA molecules spanning the lipid bilayer. The concentration of ZEA molecules is assumed to be conserved. Within the model, the interactions between lipid monolayers in a bilayer exist through ZEA molecules only. The experimental data concerning the aggregation of ZEA in DPPC from the literature and from our research were applied as a criterion to fit the model parameters. The model gives the dependences of the main phase transition temperature on ZEA/DPPC molar ratio, the percentage of ZEA in a monomeric form on ZEA/DPPC molar ratio and on temperature. The dependences obtained within the model and the experimental ones are in qualitative agreement. The influence of intermolecular interaction parameters on ZEA aggregation has been discussed. The differences between the model and the experimental results concerning mainly the pattern of ZEA aggregation have been discussed. Analyses of the lipid microconfiguration allow to advance the hypothesis concerning the influence of ZEA on the membrane permeability. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 33] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Gruszecki WI Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys PL-20031 Lublin Poland Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys PL-20031 Lublin Poland Med Acad, Dept Biophys PL-20059 Lublin Poland 25 UI - 388JT-0025 AU - Sujak A AU - Okulski W AU - Gruszecki WI TI - Organisation of xanthophyll pigments lutein and zeaxanthin in lipid membranes formed with dipalmitoylphosphatidylcholine SO - Biochimica et Biophysica Acta - Biomembranes 2000 Dec 20;1509(1-2):255-263 IS - 0005-2736 MH - Carotenoid MH - Xanthophyll pigment MH - Lipid membrane MH - Molecular aggregate MH - Retina MH - Oxidative damage MH - Macular pigment MH - Carotenoids MH - Organization MH - Liposomes AB - Carotenoid pigments and in particular xanthophylls play several physiological functions in plant and animal membranes. Xanthophylls are present in biological membranes in the form of pigment-protein complexes but also as direct components of lipid phase. The biological activity of carotenoids in membranes depends on a molecular organisation of pigments in lipid bilayers, in particular the localisation, orientation and aggregational state. In the present work the organisation of lutein- and zeaxanthin-containing lipid membranes was analysed with the application of electronic absorption spectroscopy. Both xanthophyll pigments incorporated to the dipalmitoylphosphatidylcholine (DPPC) unilamellar liposomes form I-I-type molecular aggregates, manifested by the hypsochromic shift of the main absorption band of carotenoids. The aggregation of lutein and zeaxanthin in DPPC membranes was observed even at relatively low concentrations of a pigment in the lipid phase (1-5 mol%). Gaussian analysis of the absorption spectra of lutein and zeaxanthin in DPPC membranes in terms of the exciton splitting theory revealed the formation of different molecular structures of pigments interpreted as dimers, trimers, tetramers and large aggregates. The fraction of lutein and zeaxanthin in the monomeric form was found to depend on the physical state of the lipid phase. Pronounced monomerisation of lutein and zeaxanthin was observed as accompanying the transition from the P-beta' phase to the L-alpha phase of DPPC, mostly at the expense of the trimeric and tetrameric forms. The fraction of monomers of lutein is always lower by 10-30% than that of zeaxanthin under the same experimental conditions. Different organisational forms of lutein and zeaxanthin in the model system studied are discussed in terms of possible physiological functions of these pigments in the membranes of the retina: zeaxanthin in the protection of the lipid phase against oxidative damage and lutein in absorbing short wavelength radiation penetrating retina membranes. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 26] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Gruszecki WI Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys PL-20031 Lublin Poland Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys PL-20031 Lublin Poland Med Acad, Dept Biophys PL-20059 Lublin Poland 26 UI - 389HT-0001 AU - Gilderson G AU - Aagaard A AU - Gomes CM AU - Adelroth P AU - Teixeira M AU - Brzezinski P TI - Kinetics of electron and proton transfer during O-2 reduction in cytochrome aa(3) from A-ambivalens: an enzyme lacking Glu(I-286) SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):261-270 IS - 0005-2728 MH - Cytochrome c oxidase MH - Quinol oxidase MH - Flow flash MH - Proton pumping MH - Gating MH - C-oxidase MH - Quinol oxidase MH - Acidianus-ambivalens MH - Desulfurolobus-ambivalens MH - Thermus-thermophilus MH - Escherichia-coli MH - Paracoccus-denitrificans MH - Rhodobacter-sphaeroides MH - 2.8 angstrom MH - Dioxygen AB - Acidianus ambivalens is a hyperthermoacidophilic archaeon which grows optimally at similar to 80 degreesC and pH 2.5. The terminal oxidase of its respiratory system is a membrane-bound quinol oxidase (cytochrome aa(3)) which belongs to the heme-copper oxidase superfamily. One difference between this quinol oxidase and a majority of the other members of this family is that it lacks the highly-conserved glutamate (Glu(I-286), E. coli ubiquinol oxidase numbering) which has been shown to play a central role in controlling the proton transfer during reaction of reduced oxidases with oxygen. In this study we have investigated the dynamics of the reaction of the reduced A. ambivalens quinol oxidase with O-2. With the purified enzyme, two kinetic phases were observed with rate constants of 1.8 . 10(4) s(-1) (at 1 mM O-2, pH 7.8) and 3.7 x 10(3) s(-1), respectively. The first phase is attributed to binding of O-2 to heme a(3) and oxidation of both hemes forming the 'peroxy' intermediate. The second phase was associated with proton uptake from solution and it is attributed to formation of the 'oxo-ferryl' state, the final state in the absence of quinol. In the presence of bound caldariella quinol (QH(2)), heme a was re-reduced by QH(2) with a rate of 670 s(-1), followed by transfer of the fourth electron to the binuclear center with a rate of 50 s(-1). Thus, the results indicate that the quinol donates electrons to heme a, followed by intramolecular transfer to the binuclear center. Moreover, the overall electron and proton-transfer kinetics in the A. ambivalens quinol oxidase are the same as those in the E. coli ubiquinol oxidase, which indicates that in the A. ambivalens enzyme a different pathway is used for proton transfer to the binuclear center and/or other protonatable groups in an equivalent pathway are involved. Potential candidates in that pathway are two glutamates at positions (I-80) and (I-83) in the A. ambivalens enzyme (corresponding to Met(I-116) and Val(I-119), respectively, in E. coli cytochrome bos). (C) 2001 Elsevier Science B.V. All rights reserved. [References: 43] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Brzezinski P Univ Calif San Diego, Dept Phys La Jolla, CA 92093 USA Stockholm Univ, Arrhenius Labs Nat Sci, Dept Biochem SE-10691 Stockholm Sweden Univ Nova Lisboa, Inst Tecnol Quim & Biol P-2780156 Oeiras Portugal Univ Gothenburg, Dept Biochem & Biophys SE-40530 Gothenburg Sweden 27 UI - 389HT-0002 AU - Wunschiers R AU - Senger H AU - Schulz R TI - Electron pathways involved in H-2-metabolism in the green alga Scenedesmus obliquus SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):271-278 IS - 0005-2728 MH - Ferredoxin MH - Green alga MH - Hydrogenase MH - Mehler reaction MH - Photosynthesis MH - Chlorophyll fluorescence MH - Hydrogen-production MH - Purification MH - Fluorometer MH - Mechanism MH - Proteins MH - Nickel AB - The green alga Scenedesmus obliquus is capable of both uptake and production of H-2 after anaerobic adaptation (photoreduction of CO2 or photohydrogen production). The essential enzyme for H-2-metabolism is a NiFe-hydrogenase with a [2Fe-2S]-ferredoxin as its natural redox partner. Western blot analysis showed that the hydrogenase is constitutively expressed. The K-m values were 79.5 muM and 12.5 muM, determined with ferredoxin and H-2, respectively, as electron donor for the hydrogenase. In vitro, NADP(+) was reduced by H-2 in the presence of the hydrogenase, the ferredoxin and a ferredoxin-NADP reductase. From these results and considerations on the stoichiometry we propose that this light-independent electron transfer is part of the photoreduction of CO2 in vivo. For ATP synthesis, necessary for the photoreduction of CO2, light-dependent cyclic electron transfer around Photosystem (PS) I accompanies this 'dark reaction'. PS II fluorescence data suggest that (a) in S. obliquus H-2-reduction might function as the anaerobic counterpart of the O-2-dependent Mehler reaction, and (b) the presence of either a ferredoxin quinone-reductase or NAD(P)-dehydrogenase (complex I) in S. obliquus chloroplasts. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 35] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Wunschiers R Uppsala Univ, Dept Plant Physiol, EBC Villavagen 6 S-75236 Uppsala Sweden Univ Marburg, Fachbereich Biol Bot D-35032 Marburg Germany 28 UI - 389HT-0003 AU - Sone N AU - Nagata K AU - Kojima H AU - Tajima J AU - Kodera Y AU - Kanamaru T AU - Noguchi S AU - Sakamoto J TI - A novel hydrophobic diheme c-type cytochrome. Purification from Corynebacterium glutamicum and analysis of the QcrCBA operon encoding three subunit proteins of a putative cytochrome reductase complex SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):279-290 IS - 0005-2728 MH - Quinol cytochrome c reductase MH - Cytochrome cc MH - Glutamate fermentation MH - (corynebacterium glutamicum) MH - Thermophilic bacterium ps3 MH - Rieske fes-protein MH - Bacillus-stearothermophilus MH - Electron-transfer MH - Mycobacterium-tuberculosis MH - Proton translocation MH - Energy transduction MH - Bc complex MH - Q-cycle MH - Sequence AB - Electrophoresis of a Corynebacterium glutamicum membrane preparation in the presence of sodium dodecyl sulfate, followed by staining for peroxidase activity theme staining), showed only one band at about 28 kDa. This 28 kDa protein was purified from C. glutamicum membranes by chromatography in the presence of decylglucoside using DEAE-Toyopearl and hydroxylapatite columns, as the sole c-type cytochrome in the bacterium. The cytochrome showed an alpha band at 551 nm, and its E-m,E-7 was about 210 mV. A QcrCAB operon encoding the subunits of a putative quinol cytochrome c reductase was found 3'-downstream of ctaE encoding subunit III of cytochrome aa(3) in the C. glutamicum genome. The deduced amino acid sequence of qcrC, composed of 283 amino acid residues, contained two heme C-binding motifs and was in agreement with partial peptide sequences obtained from the 28 kDa protein after V8 protease digestion. We propose to name this protein cytochrome cc, The presence of cytochrome cc is a common feature of high G+C content Gram-positive bacteria, since we could confirm this protein by electrophoresis; homologous QcrCAB operons are also known in Mycobacterium and Streptomyces. On A and qcrB of C, glutamicum encode the Rieske Fe-S protein and cytochrome b, respectively, although these proteins were not co-purified with cytochrome cc. The phylogenetic tree of cytochromes b and bs show that C. glutamicum cytochrome b, along with those of other bacteria in the high G+C group, is rather different from the Bacillus counterparts, but highly similar to the Deinococci and Thermus cytochromes. This indicates that there is a fourth group of bacteria in addition to the three clades: proteobacterial cytochrome b, cyanobacterial bs and green sulfur-low G+C Grampositive bacteria. (C) 2001 Published by Elsevier Science B.V. [References: 40] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Sone N Kyushu Inst Technol, Dept Biochem Engn & Sci 680-4 Kawazu Iizuka Fukuoka 8208502 Japan Kyushu Inst Technol, Dept Biochem Engn & Sci Iizuka Fukuoka 8208502 Japan Hyogo Med Univ, Dept Bacteriol Nishinomiya Hyogo 663 Japan 29 UI - 389HT-0004 AU - Grudzinski W AU - Matula M AU - Sielewiesiuk J AU - Kernen P AU - Krupa Z AU - Gruszecki WI TI - Effect of 13-cis violaxanthin on organization of light harvesting complex II in monomolecular layers SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):291-302 IS - 0005-2728 MH - Xanthophyll cycle MH - Violaxanthin MH - Photoisomerization MH - Lhcii MH - Photosystem-ii MH - Higher-plants MH - Xanthophyll cycle MH - Chlorophyll-a MH - Lhc-ii MH - Membranes MH - Oligomerization MH - Fluorescence MH - Carotenoids MH - Zeaxanthin AB - Lutein, neoxanthin and violaxanthin are the main xanthophyll pigment constituents of the largest light-harvesting pigment-protein complex of photosystem II (LHCII). High performance liquid chromatography analysis revealed photoisomerization of LHCII-bound violaxanthin from the conformation all-trans to the conformation 13-cis and 9-cis. Maximally, the conversion of 15% of all-trans violaxanthin to a cis form could be achieved owing to the light-driven reactions. The reactions were dark-reversible. The all-trans to cis isomerization was found to be driven by blue light, absorbed by chlorophylls and carotenoids, as well as by red light, absorbed exclusively by chlorophyll pigments. This suggests that the photoisomerization is a carotenoid triplet-sensitized reaction. The monomolecular layer technique was applied to study the effect of the 13-cis conformer of violaxanthin and its de-epoxidized form, zeaxanthin, on the organization of LHCII as compared to the all-trans stereoisomers. The specific molecular areas of LHCII in the two-component system composed of protein and exogenous 13-cis violaxanthin or 13-cis zeaxanthin show overadditivity, which is an indication of the xanthophyll-induced disassembly of the aggregated forms of the protein. Such an effect was not observed in the monomolecular layers of LHCII containing all-trans conformers of violaxanthin and zeaxanthin. 77 K chlorophyll a fluorescence emission spectra recorded from the Langmuir-Blodgett (L-B) films deposited to quartz from monomolecular layers formed with LHCII and LHCII in the two-component systems with all-trans and 13-cis isomers of violaxanthin and zeaxanthin revealed opposite effects of both conformers on the aggregation of the protein. The cis isomers of both xanthophylls were found to decrease the aggregation level of LHCII and the all-trans isomers increased the aggregation level. The calculated efficiency of excitation energy transfer to chlorophyll a from violaxanthin assumed to remain in two steric conformations was analyzed on the basis of the chlorophyll a fluorescence excitation spectra and the mean orientation of violaxanthin molecules in LHCII (71 degrees with respect to the normal to the membrane), determined recently in the linear dichroism experiments [Gruszecki et al., Biochim. Biophys. Acta 1412 (1999) 173-183]. The calculated efficiency of excitation energy transfer from the violaxanthin pool assumed to remain in conformation all-trans was found to be almost independent on the orientation angle within a variability range. In contrast the calculated efficiency of energy transfer from the form cis was found to be strongly dependent on the orientation and varied between 1.0 (at 67.48 degrees) and 0 (at 70.89 degrees). This is consistent with two essentially different, possible functions of the cis forms of violaxanthin: as a highly efficient excitation donor (and possibly energy transmitter between other chromophores) or purely as a LHCII structure modifier. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 36] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Gruszecki WI Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys Pl M Curie Sklodowskiej 1 PL-20031 Lublin Poland Marie Curie Sklodowska Univ, Inst Phys, Dept Biophys PL-20031 Lublin Poland EMPA, Swiss Fed Labs Mat Testing & Res CH-9014 St Gallen Switzerland Marie Curie Sklodowska Univ, Inst Biol, Dept Plant Physiol PL-20031 Lublin Poland 30 UI - 389HT-0006 AU - Jekabsons MB AU - Horwitz BA TI - Nucleotide effects on liver and muscle mitochondrial non-phosphorylating respiration and membrane potential SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):314-328 IS - 0005-2728 MH - Proton leak MH - Uncoupling protein MH - Ucp2 MH - Ucp3 MH - Cytochrome-c-oxidase MH - Uncoupling protein-2 expression MH - Brown adipose-tissue MH - Rat skeletal-muscle MH - Protonmotive force MH - Thyroid-hormone MH - Transport MH - Binding MH - Atp MH - Thermogenesis AB - Uncoupling protein-1 homologs are hypothesized to mediate mitochondrial proton leak. To test this hypothesis, we determined the effects of ATP and other nucleotides on liver and skeletal muscle mitochondrial non-phosphorylating respiration (VO2), membrane potential, FCCP-stimulated respiratory control ratios, and swelling. Neither ATP nor CTP affected liver or muscle proton leak, but both inhibited the respiratory chain. Unexpectedly, CMP stimulated liver proton leak (EC50 approximate to 4.4 +/- 0.5 mM). Using CMP chromatography, we identified two proteins (M-r = 31.2 and 32.6 kDa) from liver mitochondria that are similar in size to members of the mitochondrial carrier protein family. We conclude (a) liver and muscle mitochondrial proton leak is insensitive to ATP and CTP, and (b) CMP activates a leak in liver mitochondria. The CMP-inducible leak may be mediated by a 30-32 kDa protein. Based on the high concentrations required, CMP is unlikely to be a physiologically important leak regulator. Nonetheless, our results show that tissues other than brown fat have inducible leaks that may be protein-mediated. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 34] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Jekabsons MB MRC, Dunn Human Nutr Unit MRC Wellcome Trust Bldg,Hills Rd Cambridge CB2 2XY England Univ Calif Davis, Div Biol Sci, Sect Neurobiol Physiol & Behav Davis, CA 95616 USA 31 UI - 389HT-0008 AU - Steglich C AU - Behrenfeld M AU - Koblizek M AU - Claustre H AU - Penno S AU - Prasil O AU - Partensky F AU - Hess WR TI - Nitrogen deprivation strongly affects Photosystem II but not phycoerythrin level in the divinyl-chlorophyll b-containing cyanobacterium Prochlorococcus marinus SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):341-349 IS - 0005-2728 MH - Cyanobacteria MH - Phycoerythrin MH - Photosynthesis MH - Light-harvesting complex MH - Variable fluorescence MH - Nitrogen deprivation MH - Synechococcus MH - Fluorescence MH - Light MH - Phytoplankton MH - Carotenoids MH - Prokaryote MH - Physiology MH - Chlorosis MH - Pcc-7942 MH - Antenna AB - Effects of nitrogen limitation on Photosystem II (PSII) activities and on phycoerythrin were studied in batch cultures of the marine oxyphotobacterium Prochlorococcus marinus. Dramatic decreases in photochemical quantum yields (F-V/F-M), the amplitude of thermoluminescence (TL) B-band, and the rate of QA reoxidation were observed within 12 h of growth in nitrogen-limited conditions. The decline in F-V/F-M paralleled changes in the TL B-band amplitude, indicative of losses in PSII activities and formation of non-functional PSII centers. These changes were accompanied by a continuous reduction in D1 protein content. In contrast, nitrogen deprivation did not cause any significant reduction in phycoerythrin content. Our results refute phycoerythrin as a nitrogen storage complex in Prochlorococcus. Regulation of phycoerythrin gene expression in Prochlorococcus is different from that in typical phycobilisome-containing cyanobacteria and eukaryotic algae investigated so far. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 34] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Hess WR Humboldt Univ, Dept Biol Chausseestr 117 D-10115 Berlin Germany Humboldt Univ, Dept Biol D-10115 Berlin Germany US NASA, Goddard Space Flight Ctr Greenbelt, MD 20771 USA Ctr Photosynth, Inst Microbiol Trebon 37981 Czech Republic Univ Paris 06 F-06238 Villefranche Sur Mer France INSU, CNRS, Phys & Chim Marines Lab F-06238 Villefranche Sur Mer France Interuniv Inst Marine Sci, H Steinitz Marine Biol Lab IL-88103 Eilat Israel INSU, CNRS, Biol Stn F-29682 Roscoff France Univ Paris 06 F-29682 Roscoff France 32 UI - 389HT-0011 AU - Joliot P AU - Joliot A TI - Electrogenic events associated with electron and proton transfers within the cytochrome b(6)/f complex SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):369-376 IS - 0005-2728 MH - Cytochrome b/f complex MH - Electrogenic reaction MH - Electron transfer MH - Proton pump MH - B/f complex MH - Chlorella-sorokiniana MH - Transfer chain MH - Green-algae MH - Bf complex MH - Q-cycle MH - Chlamydomonas MH - Chloroplasts MH - Mechanism AB - The kinetics and amplitude of the membrane potential changes associated with electron and proton transfers within the cytochrome b(6)/f(cyt b/f) complex (phase b) are measured in vivo in Chlamydomonas reinhardtii under anaerobic conditions. Upon saturating flash excitation, fast components in the membrane potential decay superimposed on phase b lead to an underestimation of the amplitude of this phase. In the FUD50 mutant strain, which lacks the ATP synthase, the decay of the membrane potential is slowed down compared to the wild type, and the kinetics and amplitude of phase b may be accurately determined. This amplitude corresponds to the transfer of at least 1.5 charges across the membrane per positive charge transferred to photosystem I, whatever the flash energy. This value largely exceeds that predicted by a Q-cycle process. Similar conclusions are reached using the wild type strain in the presence of 9 muM dicyclohexylcarbodiimide, which specifically inhibits the ATP synthase. It is concluded that a proton pumping process is operating in parallel with the Q-cycle, with a yield of similar to 0.5 proton pumped by cyt b/f complex turnover, irrespective of the flash energy. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 25] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Joliot A Inst Biol Physicochim, CNRS, UPR 1261 13 Rue Pierre & Marie Curie F-75005 Paris France Inst Biol Physicochim, CNRS, UPR 1261 F-75005 Paris France 33 UI - 389HT-0012 AU - Seo D AU - Tomioka A AU - Kusumoto N AU - Kamo M AU - Enami I AU - Sakurai H TI - Purification of ferredoxins and their reaction with purified reaction center complex from the green sulfur bacterium Chlorobium tepidum SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):377-384 IS - 0005-2728 MH - Ferredoxin MH - Green sulfur bacterium MH - Nadp(+) reduction MH - Photosynthesis MH - Reaction center MH - Polypeptide MH - Vibrioforme MH - Proteins MH - Acceptor AB - Four ferredoxin (Fd) fractions, namely, FdA-D were purified from the green sulfur bacterium Chlorobium tepidum. Their absorption spectra are typical of 2[4Fe-4S] cluster type Fds with peaks at about 385 and 280 nm and a shoulder at about 305 nm. The A(385)/A(280) ratios of the purified Fds were 0.76-0.80. Analysis of the N-terminal amino acid sequences of these Fds (15-25 residues) revealed that those of FdA and FdB completely agree with those deduced from the genes, fdx3 and fdx2, respectively, found in this bacterium (Chung and Bryant, personal communication). The N-terminal amino acid sequences of FdC and FdD (15 residues) were identical, and agree with that deduced from the gene fdx1 (Chung and Bryant, personal communication). The A(385) values of these Fds were unchanged when they were stored for a month at -80 degreesC under aerobic conditions and decreased by 10-15% when they were stored for 6 days at 4 degreesC under aerobic conditions, indicating that they are not extremely unstable. In the presence of Fd-NADP(+) reductase from spinach, and a purified reaction center (RC) preparation from C. tepidum composed of five kinds of polypeptides, these Fds supported the photoreduction of NADP(+) at room temperature with the following K-m and V-max (in mu mol NADP(+) mu mol BChl a(-1) h(-1)): FdA, 2.0 muM and 258; FdB, 0.49 muM and 304; FdC, 1.13 muM and 226; FdD, 0.5 muM and 242; spinach Fd, 0.54 muM and 183. The V-max value of FdB was more than twice that previously reported for purified RC preparations from green sulfur bacteria. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 27] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Seo D Waseda Univ, Sch Educ, Dept Biol, Shinjuku Ku 1-6-1 Nishiwaseda Tokyo 1698050 Japan Waseda Univ, Sch Educ, Dept Biol, Shinjuku Ku Tokyo 1698050 Japan Waseda Univ, Grad Sch Sci & Engn, Dept Pure & Appl Phys, Shinjuku Ku Tokyo 1698555 Japan Iwate Med Univ, Sch Dent, Dept Biochem Morioka Iwate 0208505 Japan Sci Univ Tokyo, Fac Sci, Dept Biol, Shinjuku Ku Tokyo 1628601 Japan 34 UI - 389HT-0013 AU - Ferjani A AU - Abe S AU - Ishikawa Y AU - Henmi T AU - Tomokawa Y AU - Nishi Y AU - Tamura N AU - Yamamoto Y TI - Characterization of the stromal protease(s) degrading the cross-linked products of the D1 protein generated by photoinhibition of photosystem II SO - Biochimica et Biophysica Acta - Bioenergetics 2001 Jan 19;1503(3):385-395 IS - 0005-2728 MH - D1 protein MH - Cytochrome b(559) MH - Cross-linked product MH - Stromal protease MH - Photoinhibition MH - Photosystem ii MH - Escherichia-coli MH - Reaction centers MH - Side photoinhibition MH - Singlet oxygen MH - Alpha-subunit MH - Turnover MH - Light MH - Degradation MH - Identification MH - Inactivation AB - When photosystem (PS) II-enriched membranes are exposed to strong light, cross-linking of the intrinsic D1 protein with the surrounding polypeptides and degradation of the D1 protein take place. The cross-linking of the D1 protein with the alpha -subunit of cytochrome b(559) is suggested to be an early event of photoinduced damage to the D1 protein (Barbato et al., FEES Lett. 309 (1992) 165-169). The relationship between the cross-linking and the degradation of the D1 protein, however, is not yet clear. In the present study, we show that the addition of stromal extract from chloroplasts degrades the 41 kDa crosslinked product of D1/cytochrome b(559) alpha -subunit and enhances the degradation of the D1 protein. Incubation of the preilluminated PS II-enriched membranes with the stromal extract at 25 degreesC causes the degradation of the cross-linked product by more than 70%. The activity of the stromal extract showed a pH optimum at 8.0, and was enhanced by the addition of ATP or GTP. Consistent with the nucleotide effect, this stromal activity was eliminated by the preincubation of the stromal extract with apyrase, which hydrolyzes nucleotides. Also, the stromal activity was nearly fully inhibited by a serine-type protease inhibitor, 3,4-dichloroisocoumarin, which suggests participation of a serine-type protease(s). (C) 2001 Elsevier Science B.V. All rights reserved. [References: 26] LG - English PT - Article SB - Current Contents(R)/Life Sciences IN - Yamamoto Y Okayama Univ, Fac Sci, Dept Biol 2-5-1 Shikata Cho Okayama 7008530 Japan Okayama Univ, Fac Sci, Dept Biol Okayama 7008530 Japan Fukuoka Womans Univ, Dept Human & Environm Sci Fukuoka 8138529 Japan 35 UI - 388VB-0019 AU - Kim MS AU - McMurtrey JE AU - Mulchi CL AU - Daughtry CST AU - Chappelle EW AU - Chen YR TI - Steady-state multispectral fluorescence imaging system for plant leaves SO - Applied Optics 2001 Jan 1;40(1):157-166 IS - 0003-6935 MH - Laser-induced fluorescence MH - Leaf gas-exchange MH - Chlorophyll fluorescence MH - Green plants MH - Crop residue MH - Co2 MH - Blue MH - Reflectance MH - Signatures MH - Responses AB - We present a detailed description of a laboratory-based multispectral fluorescence imaging system (MFIS) for plant leaves. Fluorescence emissions with 360-nm excitation are captured at four spectral bands in the blue, green, red, and far-red regions of the spectrum centered at 450, 550, 680, and 740 nm, respectively. Preliminary experiments conducted with soybean leaves treated with a herbicide (DCMU) and short-term exposures to moderately elevated tropospheric ozone environment demonstrated the utilities of the newly developed MFIS. In addition, with the aid of fluorescence images of normal soybean leaves, several mechanisms governing the fluorescence emissions are discussed. Imaging results illustrate the versatility of fluorescence imaging, which provides information on the spatial variability of fluorescence patterns over leaf samples. OCIS codes: 170.0110, 170.6280, 300.2140, 300.2530, 040.1520. [References: 30] LG - English PT - Article SB - Current Contents(R)/Physical, Chemical & Earth Sciences Current Contents(R)/Engineering, Computing & Technology IN - Kim MS USDA, Beltsville Agr Res Ctr, Instrumentat & Sensing Lab 10300 Baltimore AVe Beltsville, MD 20705 USA USDA, Beltsville Agr Res Ctr, Instrumentat & Sensing Lab Beltsville, MD 20705 USA USDA, Beltsville Agr Res Ctr, Remote Sensing & Modeling Lab Beltsville, MD 20705 USA Univ Maryland, Dept Nat Resource Sci & Landscape Architecture College Pk, MD 20742 USA NASA, Goddard Space Flight Ctr, Biospher Sci Branch Greenbelt, MD 20771 USA