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  • Photosynthesis
  • Springer  (46)
  • American Association of Petroleum Geologists (AAPG)
  • American Geophysical Union
  • Elsevier
  • Periodicals Archive Online (PAO)
  • 1980-1984  (46)
Collection
Keywords
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Compartmentation and fluxes of inorganic phosphate in photosynthetic cells (1984)
    Springer
    Planta 161 (1984), S. 525-530 
    Details
    ISSN: 1432-2048
    Keywords: Asparagus ; Inorganic phosphate ; Ion flux ; Photosynthesis ; Relaxation kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An analysis of the compartmentation and fluxes of inorganic phosphate in isolated cladophyll cells from Asparagus officinalis was made in parallel with an ultrastructural study. The elution pattern of labelled inorganic phosphate (which indicates that the asparagus cells are behaving as a system of three compartments in series) was used to quantify the fluxes between the vacuole, cytoplasm and free space. A relaxation time of 198 min was calculated for inorganic phosphate exchange between the vacuole and cytoplasm. It is, therefore, suggested that the vacuole serves to buffer the cytoplasmic inorganic phosphate concentration in the long term. However, in the short term, exchange with the vacuole will not appreciably affect the cytoplasmic inorganic phosphate concentration and thus the partitioning of photosynthetically fixed carbon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407084
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  • 2
    Electronic Resource
    Electronic Resource
    Photosynthesis and plasmamembrane permeability properties of Prochloron (1984)
    Springer
    Archives of microbiology 138 (1984), S. 247-250 
    Details
    ISSN: 1432-072X
    Keywords: Prochloron ; Photosynthesis ; Electron transport ; CO2 fixation ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic carbon fixation of freshly isolated cells of Prochloron, the symbiont of Lissoclinum patella, proceeded at high rates (80–180 μmol O2·mgChl-1·h-1) in buffered seawater and showed a typical light response, saturating at about 300 μE·m-2·s-1. However, in NaCl solutions osmotically equivalent to seawater CO2-dependent O2 evolution ceased or was severely inhibited. Hypotonic or hypertonic conditions induce degrees of swelling or shrinkage, respectively, apparently causing similar increases in the plasmamembrane's permeability to ferricyanide. Initially high, but rapidly declining, rates of electron transport were observed when the cells were suspended in distilled water. This inhibition was not caused by rupture of the cells, indicating instead diffusive loss of some essential factor(s) which normally exchange easily and rapidly between the cells and/or the host environment. Such rapid exchange may be part of the mechanism of this symbiosis and, if not adequately understood, may frustrate attempts to culture Prochloron away from its host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402130
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  • 3
    Electronic Resource
    Electronic Resource
    Glycogen content and nitrogenase activity in Anabaena variabilis (1984)
    Springer
    Archives of microbiology 140 (1984), S. 120-125 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Glycogen ; Fructose ; Reductant supply ; Nitrogenase ; Oxygen protection ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogenase (=acetylene-reducing activity) was followed during photoautotrophic growth of Anabaena variabilis (ATCC 29413). When cell density increased during growth, (1) inhibition of light-dependent activity by DCMU, an inhibitor of photosynthesis, increased, and (2) nitrogenase activity in the dark decreased. Addition of fructose stabilized dark activity and alleviated the DCMU effect in cultures of high cell density. The resistance of nitrogenase towards oxygen inactivation decreased after transfer of autotrophically grown cells into the dark at subsequent stages of increasing culture density. The inactivation was prevented by addition of fructose. Recovery of acetylene-reducing activity in the light, and in the dark with fructose present, was suppressed by ammonia or chloramphenicol. In the light, also DCMU abolished recovery. To prove whether the observed effects were related to a lack of photosynthetic storage products, glycogen of filaments was extracted and assayed enzymatically. The glycogen content of cells was highest 10 h after inoculation, while light-dependent nitrogenase activity was at its maximum about 24 h after inoculation. Glycogen decreased markedly as growth proceeded and dropped sharply when the cells were transferred to darkness. Thus, when C-supply (by photosynthesis or added fructose) was not effective, the glycogen content of filaments determined the activity of nitrogenase and its stability against oxygen. In cells lacking glycogen, nitrogenase activity recovered only when carbohydrates were supplied by exogenously added fructose or by photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454913
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  • 4
    Electronic Resource
    Electronic Resource
    Inhibition of electron transfer through the cytochrome b-c 1 complex by nitric oxide in a photodenitrifier, Rhodopseudomonas sphaeroides forma sp. denitrificans (1984)
    Springer
    Archives of microbiology 139 (1984), S. 179-183 
    Details
    ISSN: 1432-072X
    Keywords: NO inhibition ; b-c 1 complex ; Photosynthesis ; Nitrite reduction ; Denitrifying Rhodopseudomonas sphaeroides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitric oxide (NO) on electron transfer were studied with a photodenitrifier, Rhodopseudomonas sphaeroides forma sp. denitrificans. NO inhibited the oxidation of cytochrome c induced by continuous illumination in intact cells. NO inhibited the re-reduction of cytochrome c, the slow phase of the carotenoid bandshift, and the oxidation of cytochrome b after a flash illumination, suggesting that NO inhibited the photosynthetic cyclic electron transfer through the cytochrome b-c 1 region. NO also inhibited the nitrite (NO 2 - ) and NO reductions with succinate as the electron donor in intact cells, but did not inhibit the NO 2 - and NO reductions in chromatophore membranes with ascorbate and phenazine methosulfate as the electron donors. NO reversibly inhibited the ubiquinol: cytochrome c oxidoreductase of the membranes, suggesting that NO inhibited the electron transfer through the cytochrome b-c 1 region and that the cytochrome b-c 1 complex also was involved in the electron transport in both NO 2 - and NO reductions. The catalytic site of NO reduction was distinct from the inhibitory site of NO.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401996
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  • 5
    Electronic Resource
    Electronic Resource
    Site of action of the natural algicide, cyanobacterin, in the blue-green alga, Synechococcus sp. (1984)
    Springer
    Archives of microbiology 138 (1984), S. 273-277 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Secondary metabolite ; Allelopathy ; Photosynthesis ; Electron transport ; Thylakoids ; Herbicides ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterin is a secondary metabolite produced by the cyanobacterium, Scytonema hofmanni. Highly purified cyanobacterin was found to inhibit the growth of many cyanobacteria at a minimum effective dose of 2 μg/ml (4.6 μM). The antibiotic had no effect on eubacteria including the photosynthetic Rhodospirillum rubrum. The site of action of cyanobacterin was further investigated in the unicellular cyanobacterium, Synechococcus sp. Electron micrographs of antibiotic-treated Synechococcus cells indicated that cyanobacterin affects thylakoid membrane structure. The antibiotic also inhibited light-dependent oxygen evolution in Synechococcus cells and in spheroplasts. These data support our conclusion that cyanobacterin specifically inhibits photosynthetic electron transport. This activity is similar to herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). The anhydro analog of cyanobacterin had no biological activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402134
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  • 6
    Electronic Resource
    Electronic Resource
    Contrasting modes of photosynthetic enzyme regulation in oxygenic and anoxygenic prokaryotes (1984)
    Springer
    Archives of microbiology 139 (1984), S. 124-129 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Regulation ; Thioredoxin ; Cyanobacterium ; Chromatium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enzymes that are regulated by the ferredoxin/thioredoxin system in chloroplasts — fructose-1,6-bisphosphatase (FBPase), sedoheptulose-1,7-bisphosphatase purified from two different types of photosynthetic prokaryotes (cyanobacteria, purple sulfur bacteria) and tested for a response to thioredoxins. Each of the enzymes from the cyanobacterium Nostoc muscorum, an oxygenic organism known to contain the ferredoxin/thioredoxin system, was activated by thioredoxins that had been reduced either chemically by dithiothreitol or photochemically by reduced ferredoxin and ferredoxin-thioredoxin reductase. Like their chloroplast counterparts, N. muscorum FBPase and SBPase were activated preferentially by reduced thioredoxin f. SBPase was also partially activated by thioredoxin m. PRK, which was present in two regulatory forms in N. muscorum, was activated similarly by thioredoxins f and m. Despite sharing the capacity for regulation by thioredoxins, the cyanobacterial FBPase and SBPase target enzymes differed antigenically from their chloroplast counterparts. The corresponding enzymes from Chromatium vinosum, an anoxygenic photosynthetic purple bacterium found recently to contain the NADP/thioredoxin sytem, differed from both those of cyanobacteria and chloroplasts in showing no response to reduced thioredoxin. Instead, C. vinosum FBPase, SBPase, and PRK activities were regulated by a metabolite effector, 5′-AMP. The evidence is in accord with the conclusion that thioredoxins function in regulating the reductive pentose phosphate cycle in oxygenic prokaryotes (cyanobacteria) that contain the ferredoxin/thioredoxin system, but not in anoxygenic prokaryotes (photosynthetic purple bacteria) that contain the NADP/thioredoxin system. In organisms of the latter type, enzyme effectors seem to play a dominant role in regulating photosynthetic carbon dioxide assimilation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401986
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  • 7
    Electronic Resource
    Electronic Resource
    Chloroplast thylakoid membrane fluidity and its sensitivity to temperature (1984)
    Springer
    Planta 161 (1984), S. 375-380 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast (membrane fluidity ; Fluorescence (polarization, temperature) ; Lipid (thylakoid membrane) ; Membrane (fluidity, temperature) ; Photosynthesis ; Pisum (thylakoid membrane) ; Thylakoid membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to investigate membrane fluidity, the hydrophobic probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), has been incorporated into intact isolated thylakoids and separated granal and stromal lamellae obtained from the chloroplasts of Pisum sativum. The steady-state polarization of DPH fluorescence was measured as a function of temperature and indicated that at physiological values the thylakoid membrane is a relatively fluid system with the stromal lamellae being less viscous than the lamellae of the grana. According to the DPH technique, neither region of the membrane, however, showed a sharp phase transition of its bulk lipids from the liquid-crystalline to the gel state for the temperature range -20° to 50° C. Comparison of intact thylakoids isolated from plants grown at cold (4°/7°C) and warm (14°/17° C) temperatures indicate that there is an adaptation mechanism operating which seems to maintain an optimal membrane viscosity necessary for growth. Using a modified Perrin equation the optimal average viscosity for the thylakoid membrane of the chill-resistant variety used in the study (Feltham First) is estimated to be about 1.8 poise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398729
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of sediment moisture on carbon dioxide exchange inSpartina alterniflora (1984)
    Springer
    Plant and soil 79 (1984), S. 291-293 
    Details
    ISSN: 1573-5036
    Keywords: Photosynthesis ; Salt marsh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Effect of moisture stress on photosynthesis activity ofSpartina alterniflora was studied using sediment cores taken from a Louisiana Gulf Coast salt marsh. Moisture stress was induced by evapotranspiration losses which simulate conditions that can occur when a salt marsh is not inundated by tidal cycles for extended periods. Changes in the sediment moisture from 70% to 28% when expressed as a percentage of the wet weight resulted in a rapid decrease in net CO2 fixation. The moisture content of this sediment remained above saturation throughout the experiment although the solute or osmotic potential was equivalent to being in the range between field capacity and permanent willing. Net fixation was correlated with the moisture content (r=0.92**). Plant photosynthetic activity decreased at sediment moisture levels below 70%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182352
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  • 9
    Electronic Resource
    Electronic Resource
    Purification and properties of the adenylate kinases from Rhodopseudomonas palustris, Rhodopseudomonas sphaeroides and Rhodopseudomonas rubrum (1983)
    Springer
    Archives of microbiology 134 (1983), S. 153-157 
    Details
    ISSN: 1432-072X
    Keywords: Adenylate kinase ; Chromatophores ; Membranes ; Photosynthesis ; Rhodopseudomonas ; Rhodospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The adenylate kinases (EC 2.7.4.3) from photosynthetically grown Rhodopseudomonas palustris, Rhodopseudomonas sphaeroides and Rhodospirillum rubrum were purified to homogeneity by the same procedure. The purified enzymes showed optimal rates of activity with MgCl2 at 25° C and pH 8.0. They were found to be heat labile and were characterized by pI-values of 4.5. Apparent molecular weights of 33 500 for R. palustris, 34 400 for R. sphaeroides and 32 100 for R. rubrum were determined by high performance liquid chromatography. No separation into subunits was observed by use of sodium dodecylsulfate polyacrylamide gel electrophoresis. The apparent K m -values for ADP corresponded to 0.26 mM for R. palustris, 0.27 mM for R. sphaeroides and 0.24 mM for R. rubrum. ADP in excess had a strong inhibitory effect. Competitive product inhibition was found for AMP, with K i-values of 0.017 mM for R. palustris, 0.018 mM for R. sphaeroides and 0.014 mM for R. rubrum. A competitive inhibitor likewise was P1,P5-di(adenosine-5′)pentaphosphate with K i-values of 0.020 μM for R. palustris and R. sphaeroides, and 0.017 μM for R. rubrum. Sulfhydryl-reacting reagents like p-chloromercuribenzoate and iodoacetic acid were found to be non-inhibitory. All measurements of adenylate kinase activity were carried out with the stabilized and most sensitive luciferin-luciferase system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407949
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  • 10
    Electronic Resource
    Electronic Resource
    Chromatographic and spectroscopic analysis of phycoerythrin 545 and its subunits (1983)
    Springer
    Archives of microbiology 135 (1983), S. 194-198 
    Details
    ISSN: 1432-072X
    Keywords: Cryptomonads ; Biliproteins ; Photosynthesis ; Accessory pigments ; Phycoerythrin ; Confirmation of biliproteins ; Solar energy harvesting ; Billins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phycoerythrin 545 is a light-harvesting biliprotein isolated from the cryptomonad Rhodomonas lens. Although the absorption spectrum of the native protein suggests that this protein has only phycoerythrobilins for its chromophores, the denaturated protein shows a small near ultraviolet absorption band with a maximum at 333 nm which is not present in phycoerythrobilin. Two methods were employed to separate the α and β subunits of this protein: chromatography with Sephacryl S-200 in acidic urea or centrifugation in a sucrose density gradient at pH 3.0. The chromatography experiments yielded two bands, which were shown to be pure α or β subunits by sodium dodecyl sulfate gel electrophoresis. The absorption spectrum of β showed only phycoerythrobilins, but the spectrum of α was not like that of any known bilin chromophore. Its absorption spectrum could be constructed by a combination of phycoerythrobilin and cryptoviolin. The β subunit separated on the sucrose density gradient was highly aggregated. Circular dichroism and fluorescence polarization spectroscopy indicated that this aggregated β subunit has chromophores in atypical environments. Comparison of the absorption, spectra of native and denatured phycoerythrin 545 suggests that chromophores in the native state are held by the protein in a more linear confirmation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414479
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  • 11
    Electronic Resource
    Electronic Resource
    Nitrogen nutrition, photosynthesis and carbon allocation in ectomycorrhizal pine (1983)
    Springer
    Plant and soil 71 (1983), S. 415-431 
    Details
    ISSN: 1573-5036
    Keywords: Carbon allocation ; Light Mycorrhizas ; Nitrogen ; Phosphorus ; Photosynthesis ; Pinus contorta ; Pinus taeda ; Pisolithus tinctorius ; Respiration ; Source-sink ; Suillus granulatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies examined net photosynthesis (Pn) and dry matter production of mycorrhizal and nonmycorrhizalPinus taeda at 6 intervals over a 10-month period. Pn rates of mycorrhizal plants were consistently greater than nonmycorrhizal plants, and at 10 months were 2.1-fold greater. Partitioning of current photosynthate was examined by pulse-labelling with14CO2 at each of the six time intervals. Mycorrhizal plants assimilated more14CO2, allocated a greater percentage of assimilated14C to the root systems, and lost a greater percentage of14C by root respiration than did nonmycorrhizal plants. At 10 months, the quantity of14CO2 respired by roots per unit root weight was 3.6-fold greater by mycorrhizal than nonmycorrhizal plants. Although the stimulation of photosynthesis and translocation of current photosynthate to the root system by mycorrhiza formation was consistent with the source-sink concept of sink demand, foliar N and P concentrations were also greater in mycorrhizal plants. Further studies examined Pn and dry matter production ofPinus contorta in response to various combinations of N fertilization (3, 62, 248 ppm), irradiance and mycorrhizal fungi inoculation. At 16 weeks of age, 6 weeks following inoculation with eitherPisolithus tinctorius orSuillus granulatus, Pn rates and biomass were significantly greater in mycorrhizal than nonmycorrhizal plants. Mycorrhizal plants had significantly greater foliar %P, but not %N, than did nonmycorrhizal plants. Fertilization with 62 ppm N resulted in greater mycorrhiza formation than either 3 or 248 ppm. Increased irradiance resulted in increased mycorrhiza formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182683
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  • 12
    Electronic Resource
    Electronic Resource
    Influence of methionine sulfoximine on the photosynthesis of isolated chloroplasts (1983)
    Springer
    Photosynthesis research 4 (1983), S. 241-244 
    Details
    ISSN: 1573-5079
    Keywords: Chloroplasts ; Methionine sulfoximine ; Photosynthesis ; Pisum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methionine sulfoximine provided at a concentration which inhibits photosynthesis in intact leaves (10 mM) had no significant influence on the rate of photosynthesis of isolated pea leaf chloroplasts. In contrast, ammonium, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and D,L-glyceraldehyde all strongly inhibited the photosynthesis of isolated chloroplasts. We conclude that low concentrations of methionine sulfoximine (up to 10 mM) have no direct effect on the photosynthetic process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00041819
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  • 13
    Electronic Resource
    Electronic Resource
    Influence of Methionine sulfoximine on the photosynthesis of isolated chloroplasts (1983)
    Springer
    Photosynthesis research 4 (1983), S. 241-244 
    Details
    ISSN: 1573-5079
    Keywords: Chloroplasts ; Methionine sulfoximine ; Photosynthesis ; Pisum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methionine sulfoximine provided at a concentration which inhibits photosynthesis in intact leaves (10 mM) had no significant influence on the rate of photosynthesis of isolated pea leaf chloroplasts. In contrast, ammonium, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and D,L-glyceraldehyde all strongly inhibited the photosynthesis of isolated chloroplasts. We conclude that low concentrations of methionine sulfoximine (up to 10 mM) have no direct effect on the photosynthetic process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00052127
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  • 14
    Electronic Resource
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    ESR and ENDOR of primary reactants in photosynthesis (1982)
    Springer
    European biophysics journal 8 (1982), S. 107-150 
    Details
    ISSN: 1432-1017
    Keywords: Photosynthesis ; Primary reactions ; ESR ; ENDOR ; Chlorophyll ; Bacteriochlorophyll ; Pheophytin ; Bacteriopheophytin ; Ferredoxin ; Iron-sulfur protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The primary reactants in photosynthesis are defined as the chemical entities on which charges are generated and stabilized after capture of a photon by the photochemical trap: PIX → hv P * IX → P + I − X→ P + IX −, where P stands for the primary electron donor, P * for its excited singlet state, I for the ‘first’ (ESR-detectable) electron acceptor and X for the secondary acceptor complex. The ESR and ENDOR experiments which have played a rÔle in the identification and characterization of P, I, and X in the bacterial and plant photosystems are comprehensively reviewed. The structural and kinetic information obtained with magnetic resonance techniques are integrated with results obtained with optical spectroscopy to give a unified picture of the pathway of primary photochemistry in photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535455
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  • 15
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    Comparative immunological characterization of various photosynthetic cytochromes c from pro- and eukaryotic algae (1982)
    Springer
    Archives of microbiology 131 (1982), S. 356-359 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Cytochrome c ; Radioimmunoassay ; Prokaryotic/eukaryotic algae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic c-type cytochromes isolated from various pro- and eukaryotic algae have been compared by an immunochemical method. Thereby the extent of cross-reactivity of several cytochromes with antisera to cytochrome c from Spirulina platensis, Bumilleriopsis filiformis, and Scenedesmus acutus was quantitatively determined by antigen-binding tests. When immunological relationship is taken as a measure of structural relationship, the following conclusions can be drawn: (1) c-type cytochromes from Anabaena variabilis, Nostoc muscorum, Calothrix membranacea, and Spirulina platensis show large differences in cross-reactivity. (2) The acidic Spirulina cytochrome c is fairly closely related to the two eukaryotic cytochromes assayed here.
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    URL: http://dx.doi.org/10.1007/BF00411186
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  • 16
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    Energetic and metabolic requirements for the germination of akinetes of the cyanobacteriumNostoc PCC 7524 (1982)
    Springer
    Archives of microbiology 133 (1982), S. 44-49 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Akinete ; Germination ; Respiration ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although akinetes ofNostoc PCC 7524 lost little of their main photosynthetic pigments, phycocyanin and chlorophyll, with increasing age after the onset of sporulation, they lost at least 90% of their photosynthetic and respiratory capacities. Germination needed the supply of light throughout the process, though previous dark metabolism accelerated the following light process. In standard conditions, both respiratory and photosynthetic capacities increased markedly during the first 9–10 h, a time sufficient for the first doublets to appear, but when pigment contents had not yet changed. However, while respiratory capacity could be reacquired without de nove metabolism, resumption of photosynthetic capacity needed RNA and protein synthesis. The energetic requirement for germination was not efficiently fulfilled by cyclic photosynthesis on PSI alone or respiration alone. In the presence of both PSI and respiratory activities only 21% of the akinetes germinated, their endogenous carbon reserves thus being inadequate to support the process to completion. The addition of sucrose to such cultures permitted all of the akinetes to germinate, but at a very slow rate. Rapid and complete germination was only observed when both photosystem operated.
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    URL: http://dx.doi.org/10.1007/BF00943768
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  • 17
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    Loop currents in chlorophyll a (1982)
    Springer
    Theoretical chemistry accounts 61 (1982), S. 105-133 
    Details
    ISSN: 1432-2234
    Keywords: Chlorophyll ; Loop currents ; Möbius loops ; Photosynthesis ; Exciton ; Antiparamagnetism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Loop currents involve the circulation of electrons (or holes) around closed conjugated-bond loops. From the length of the orbital perimeter the kinetic energy per electron can be calculated. In chlorophyll a, four electronic excitations have been analyzed, including: (1) a single positive charge (hole) circling a 19-bond orbit with a Möbius twist (this is proposed as the effective ground state); (2) nine electrons, unevenly spaced, circling the same 19-bond orbit but without the Möbius twist (proposed as the red excited state); (3) nine electrons in the same orbit but evenly spaced and vibrationless (the hopping exciton); (4) ten electrons, unevenly spaced, in a 16-bond orbit (the blue excited state). The fit of theory to experiment is examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549138
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  • 18
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    Correlation between changes in photosynthetic activity and changes in total protoplast volume in leaf tissue from hygro-, meso- and xerophytes under osmotic stress (1982)
    Springer
    Planta 154 (1982), S. 538-545 
    Details
    ISSN: 1432-2048
    Keywords: Leaf slices ; Photosynthesis ; Protoplast volume ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of photosynthesis of leaf slices from various hygro-, meso- and xerophytes were measured in the absence of stomatal control in various stages of osmotic dehydration. The external osmotic potential π° for a 50% inhibition of photosynthesis varied between 20 bar in some hygrophytes up to 50 bar in xerophytes. The response of photosynthetic enzymes to increased salt concentrations in the reaction medium was similar in leaf extracts from hygro-, meso- and xerophytes. The total protoplast volume in vacuum-infiltrated leaf discs from various plants was measured as the difference between 3H2O-labeled space and [14C]sorbitol-labeled space. In all plants, the protoplast volume could be reduced to about 55% of the maximum volume of tissue in equilibrium with water, without decreasing photosynthesis. Reduction of the maximal protoplast volume below 55% decreased photosynthesis in all tissues to the same decreased photosynthesis in all tissues to the same degree. At 20% maximal volume, photosynthesis of all plants was completely inhibited. The differential decrease of protoplast volumes of various leaf tissues in response to changes in π° was mainly due to the different osmotic potential of the cell sap (πcs). The relative contribution of sugars to the overall osmolarity of the cell sap was up to nineteen times higher in xerophytes than in hygrophytes. Short-term recovery of photosynthesis after hypertonic stress was good in xerophytes, incomplete in mesophytes and absent in hygrophytes. There was also a large discrepancy between the partial recovery of protoplast volumes and the complete absence of a recovery of photosynthesis in hygrophytes.
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    URL: http://dx.doi.org/10.1007/BF00402997
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  • 19
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    Purine alkaloid formation and CO2 gas exchange in dependence of development and of environmental factors in leaves of Coffea arabica L. (1982)
    Springer
    Planta 156 (1982), S. 295-301 
    Details
    ISSN: 1432-2048
    Keywords: Caffeine ; Coffea ; Leaf development ; Photosynthesis ; Purine alkaloids and light ; Purine alkaloids and temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the leaves of Coffea arabica L., purine alkaloid formation was estimated by analyzing the theobromine and caffeine content and by measuring the methylation rate of [2-14C]theobromine to [2-14C]caffeine in short-term experiments (6–24 h). At the same time, growth (in terms of dry weight and area), net photosynthesis (NPS), and dark respiration were determined. During leaf development, which was considered to be terminated when NPS was at a maximum (60–80 μmol g-1 s-1) and dark respiration at a minimum (5–7.5 μmol g-1 s-1), the content of theobromine and the velocity of caffeine formation were both found to decrease by a factor of more than 100. The close correlation between the theobromine content and the methylation rate is suspended when purine alkaloid formation is influenced by factors other than leaf development. Among these factors, temperature is the most effective: the velocity of caffeine biosynthesis is increased by raising the temperature and vice versa. Although the plants were well irrigated, a drastic decrease of NPS in the afternoon was observed under all environmental conditions tested. Light saturation was reached between 170–360 μmol m-2 s-1. The temperature optimum of NPS was shown to be very broad (24–33°C)m provided the adaptation time was sufficiently long.
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    URL: http://dx.doi.org/10.1007/BF00397466
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    Effect of the D genome and of selection on photosynthesis in wheat (1982)
    Springer
    Theoretical and applied genetics 61 (1982), S. 359-365 
    Details
    ISSN: 1432-2242
    Keywords: Triticum ; D genome ; Photosynthesis ; Transpiration ; Water use efficiency ; Wheat evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Photosynthesis and transpiration in wheats and in their progenitors were analyzed in relation to their genome, ploidy and selection. The values of these parameters markedly depend on a specific effect of the D genome and on leaf enlargement in the course of evolution in wheats. Leaf enlargement has had a marked effect on photosynthesis in the genotypes that are devoid of the D genome; in addition, their photosynthetic capacity is greater in forms with lower leaf area. The increase in the mesophyll resistance rm to CO2 transfer is in relation to the increase in leaf area and is mainly responsible for the decrease in photosynthesis rate. Owing to its stomatal regulation, Triticum aestivum L. is characterized by good water use efficiency in spite of its large leaves and of its low net photosynthesis. On the basis of the photosynthesis rate, the “large leaf factor does not appear to be a good selection criterion for the Triticum durum genotypes that are devoid of the D genome.
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    URL: http://dx.doi.org/10.1007/BF00272857
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    Effects of hydroxylamine and silicomolybdate on the decay in delayed light emission in the 6–100 μs range after a single 10 ns flash in pea thylakoids (1982)
    Springer
    Photosynthesis research 3 (1982), S. 161-177 
    Details
    ISSN: 1573-5079
    Keywords: Delayed light Emission ; Hydroxylamine ; Photosynthesis ; Photosystem II ; Sillicomolybdate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Measurements are reported on μs delayed light emission, following a single 10 ns excitation flash, in Alaska pea thylakoids treated with hydroxylamine (NH2OH) or with silicomolybdate. 1. In thylakoids treated with 2 mM NH2OH in the light, or in the dark, the quantum yield of delayed light emission is considerably enhanced. A 10 μs lifetime component of delayed light emission is not significantly changed, whereas a 50–70 μs lifetime component is increased. MnCl2 and diphenylcarbazide are unable to reverse the above effects of NH2OH treatment. Thus Mn2+ and diphenylcarbazide must not donate electrons directly to reaction center II but on the oxygen-evolution side of the NH2OH block. 2. When the closed form of photosystem II reaction centers (P680Q-), where P680 is the reaction center chlorophyll and Q is a ‘stable’ electron acceptor, is generated by preillumination of NH2OH-treated thylakoids with diuron present, the μs delayed light emission is inhibited, but a low level residual delayed light emission remains. Possible origins of this emission are discussed. It is believed that the best explanation for residual DLE is the existence of another acceptor besides Q that partakes in charge separation and rapid dissipative recombination when the reaction center is in the P680Q- state. 3. The quantum yield of delayed light emission from ‘closed’ reaction centers (P680 +Q-) that have all charge stabilization reactions (i.e., flow of electrons to P680 + and out of Q-) blocked by NH2OH treatment and addition of diuron is 1.1×10-3 for components measured in a range from 6 to 400 μs and extrapolated to zero time. 4. The addition of silicomolybdate, which accepts electron from Q-, causes delayed light emission in the μs range to be greatly inhibited.
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    URL: http://dx.doi.org/10.1007/BF00032254
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    Light quantity and quality interactions in the control of elongation growth in light-grown Chenopodium rubrum L. seedlings (1981)
    Springer
    Planta 153 (1981), S. 556-560 
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    ISSN: 1432-2048
    Keywords: Chenopodium ; Cryptochrome ; Elongation growth and light ; Photoreceptor ; Photosynthesis ; Phytochrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spectral control of hypocotyl elongation in light-grown Chenopodium rubrum L. seedlings has been studied. The results showed that although the seedlings responded to changes in the quantity of combined red and far-red radiation, they were also very sensitive to changes in the quantity of blue radiation reaching the plant. Altering the proportion of red: far-red radiation in broad waveband white light caused marked differences in hypocotyl extension. Comparison of the responses of green and chlorophyll-free seedlings indicated no qualitative difference in the response to any of the light sources used, although photosynthetically incompetent plants were more sensitive to all wavelengths. Blue light was found to act primarily of a photoreceptor which is different from phytochrome. It is concluded that hypocotyl extension rate in vegetation shade is photoregulated by the quantity of blue light and the proportion of red: far-red radiation. In neutral shade, such as that caused by stones or overlying soil, hypocotyl extension appears to be regulated primarily by the quantity of light in the blue waveband and secondarily by the quantity of light in the red and far-red wavebands.
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    URL: http://dx.doi.org/10.1007/BF00385541
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    Photosynthesis and respiration of Griffithsia monilis (Rhodophyceae): Effect of light, salinity, and oxygen (1981)
    Springer
    Planta 151 (1981), S. 281-288 
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    ISSN: 1432-2048
    Keywords: CO2 Fixation ; Griffithsia ; Photorespiration ; Photosynthesis ; Respiration ; Satinity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The giant-celled alga Griffithsia monilis has a low light compensation point and saturates photosynthesis at 60–90 μmol photons m-2s-1 (oxygen evolution and CO2 fixation). Under dark and low light intensities 14C is preferentially incorporated into amino acids (mainly aspartate and alanine). With increasing light a gradual change was observed and, under light saturation, compounds of the anionic fraction (digeneaside and hexosephosphates) were the most strongly labeled compounds, together with the amino acids glycine and serine. To a large extent (30–40% of the total) 14C was fixed into EtOH-insoluble products, the hydrolysates of which consisted mainly of glucose and mannose. In the steady state the rates of photosynthesis and respiration decreased with increasing salinity. Changes in the rates after hyperosmotic shocks were less severe in cells adapted to high salinities. Photorespiration exists in Griffithsia: Glycine and serine are the major labeled compounds in O2-saturated media.
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    URL: http://dx.doi.org/10.1007/BF00395181
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    The role of endosymbiotic algae in photoaccumulation of green Paramecium bursaria (1981)
    Springer
    Planta 152 (1981), S. 268-271 
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    ISSN: 1432-2048
    Keywords: Chlorella ; Endosymbiosis ; Paramecium bursaria ; Photoaccumulation ; Photoreceptor ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The endosymbiotic unit of Paramecium bursaria with Chlorella sp. photoaccumulates in white, blue-green, and red light (λ〈700 nm), whereas alga-free Paramecia never do. The intensity of photoaccumulation depends on both the light fluence rate and the size of the symbiotic algal population. Photoaccumulation can be stopped completely with 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosynthetic electron transport. Hence the photosynthetic pigments of the algae act as receptors of the light stimulus for photomovement and a close connection must exist between photosynthesis of the algae and ciliary beating of the Paramecium.
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    URL: http://dx.doi.org/10.1007/BF00385155
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    Comparative analyses of the effect of triacontanol on photosynthesis, photorespiration and growth of tomato (C3-plant) and maize (C4-plant) (1981)
    Springer
    Planta 152 (1981), S. 44-49 
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    ISSN: 1432-2048
    Keywords: Lycopersicon ; Phetorespiration ; Photosynthesis ; Triacontanol ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato (C3-plants) and maize (C4-plants) were grown in a nutrient solution to which triacontanol was added twice a week. After about 4 weeks the triacontanol treatment caused a significant increase in the dry weight of the tomato plants. Leaf area and dry weight measurements of tomato leaves at different stages of development showed that the largest increase in growth was obtained when triacontanol treatment was initiated before bud formation. In maize, no effect of the triacontanol treatment on dry wieght was observed. Photosynthesis was inhibited by 27% in young leaves from triacontanol-treated tomato plants and 39% in the controls, when the oxygen concentration was raised from 2% to 21%. In maize no change in photosynthesis could be observed, neither after altered oxygen concentration nor after triacontanol treatment. The difference in the response of C3- and C4-plants to triacontanol indicates that it regulates processes related to photosynthesis.
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    Evidence for a dual role of cytochrome c-553 and plastocyanin in photosynthesis and respiration of the cyanobacterium, Anabaena variabilis (1981)
    Springer
    Archives of microbiology 128 (1981), S. 336-340 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Anabaena variabilis ; Electron flow ; Photosynthesis ; Respiration ; Cytochrome oxidase ; Cytochrome c-553 ; Plastocyanin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cytochrome oxidase activity (oxygen uptake in the dark) of a membrane preparation from Anabaena variabilis was found to be stimulated by cytochrome c-553 and plastocyanin obtained from this alga. Cytochrome c from horse heart was as active as cytochrome c-553, whereas little or no stimulation of oxygen uptake was obtained with cytochromes c 2 from two Rhodospirillaceae, the plastidic cytochrome c-552 from Euglena, and plastocyanin from spinach. Cytochrome c-553 (A. variabilis) stimulated photosystem 1 activity in the same preparation much more than cytochrome c (horse heart). The results indicate that cytochrome c-553 and plastocyanin, besides their established function as electron donors of photosystem 1, participate in respiratory electron transport as reductants of a terminal oxidase. Photooxidation and dark oxidation show a different donor specificity.
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    The effects of sublethal concentrations of zinc, cadmium and mercury on Euglena (1981)
    Springer
    Archives of microbiology 128 (1981), S. 407-411 
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    ISSN: 1432-072X
    Keywords: Cadmium ; Euglena ; Mercury ; Photochemical activities ; Photosynthesis ; Respiration ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Results on the effect of sub-lethal concentrations of zinc chloride (ZnCl2), cadmium chloride (CdCl2), and mercuric chloride (HgCl2) on Euglena are presented. During the growth cycle respiratory oxygen uptake and photosynthetic oxygen evolution in the light are initially strongly inhibited by Zn, Cd and Hg. The effects of the three metals on photosynthesis, using oxygen evolution as a criterion was confirmed by carbon fixation techniques. Photosystem I (PSI) associated electron transport 2,6-dichlorophenol indophenol (DCPIP)red. → methyl viologen (MV) → O2, in contrast to total photosynthetic capacity, was only slightly inhibited by Zn, Cd and Hg, whereas the levels of activity of NADP-oxidoreductase in cells untreated or treated with heavy metals showed development like total photosynthesis. Metals strongly inhibited this enzyme which means that the supply of NADPH is lowered due to the action of Zn, Cd and Hg. Photosystem II (PSII) associated electron transport (H2O → dibromothymoquinone/2,3-dimethyl-5,6-methylenedioxy-D-benzoquinone → O2), however, was severely inhibited in a way similar to total photosynthesis. Effects on the cooperation of PSI + II showed patterns similar to PSII alone, i.e., heavy metals strongly reduced PSI + II dependent activities.
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    The enzymatic system thiosulfate: Cytochrome c oxidoreductase from photolithoautotrophically grown Rhodopseudomonas palustris (1981)
    Springer
    Archives of microbiology 130 (1981), S. 328-333 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Rhodopseudomonas palustris ; Thiosulfate ; Cytochrome c ; Oxidoreductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhodopseudomonas palustris cells, characterized by a lamellar type intracytoplasmic chromatophore membrane system after phototrophic growth, yielded a crude supernatant cell-free fraction (S-144) after ultracentrifugation which retained the contents of both the cell compartments. After thiosulfate-dependent growth, a protein system was isolated from S-144 which catalyzed the thiosulfate-linked reduction of an endogenous c-type cytochrome. — The colorless oxidoreductase protein, after purification to homogeneity, revealed a molecular weight of 93,000 and, after SDS treatment, a particle weight of 48,000. It was focused at an average pI of 5.45. Apparent K m values for several substrates were in the μM range. The electron acceptor for thiosulfate oxidation was found to be a cytochrome c from S-144. The homogeneous acceptor protein, at liquid nitrogen temperature, exhibited absorption maxima at 549.0, 518.5 and 418.0 nm, and shoulders at 525.5, 512.0 and 508.0 nm. Its molecular weight was found to be 17,000 (gel filtration) and 16,000 (SDS gel electrophoresis). It was characterized by a pI of 10.0. Its midpoint redox potential of E m,7.0=+228 mV was determined by redox titrations and the value of +205 mV by spectrophotometric calculations.
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    The enzymatic system thiosulfate: Cytochrome c oxidoreductase from photolithoautotrophically grown Chromatium vinosum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 334-338 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Chromatium vinosum ; Thiosulfate ; Cytochrome c ; Oxidoreductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromatium vinosum cells form a vesicular type intracytoplasmic membrane system during phototrophic growth on thiosulfate.—An enzyme protein transferring electrons from thiosulfate to cytochromes of type c was enriched from S-144. The colorless thiosulfate: cytochrome c oxidoreductase was characterized by a molecular weight of 36,000 (after dodecylsulfate treatment) and 35,000 (by gel filtration). Isoelectric focusing revealed a pI range of 4.4 to 4.7. Apparent K m values for the cytochromes tested were in the μM range. — The endogenous electron acceptor compound, isolated from the chromatophore fraction P-144, was found to be a membrane-bound cytochrome c-552. The homogeneous cytochrome protein had an average pI value of 4.65 and a molecular weight of 71,500 determined by gel filtration. By dodecylsulfate electrophoresis it was cleaved into two proteins representing particle weights of 45,000 and 20,000.
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    Glycolate excretion by Rhodospirillum rubrum (1981)
    Springer
    Archives of microbiology 129 (1981), S. 317-320 
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    ISSN: 1432-072X
    Keywords: Glycolate excretion ; Rhodospirillum rubrum ; Rihulose bisphosphate carboxylase/oxygenase ; Photorespiration ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Glycolate can be measured in the supernatant fraction after incubation of butyrate-grown cells of Rhodospirillum rubrum either colorimetrically by the Calkins method or enzymatically using glycolate oxidase. Under optimal conditions, half-maximal excretion occurs at 11% O2 and the maximal rate is 6.9 nmol of glycolate min-1 mg protein-1 at 30°C. The pH and temperature optima are 7.6 and 30°C and light intensity is saturating in the range of 2–10×104 lux. Carbon dioxide inhibits glycolate excretion and exogenous butyrate stimulates. Glycolate excretion is maximal by butyrate-light grown cells harvested in the early stationary phase and under all conditions is proportional to the cellular content of ribulose 1,5-bisphosphate carboxylase/oxygenase.
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    Effects of water stress on cryptoendolithic cyanobacteria from hot desert rocks (1981)
    Springer
    Archives of microbiology 130 (1981), S. 267-271 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Chroococcidiopsis ; Chroococcus ; Water stress ; Photosynthesis ; Endolithic ; Matric ; Osmotic ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four strains of Chroococcidiopsis and one Chroococcus, all isolated from extreme arid desert rocks, and one marine Chroococcus, were subjected to water stress using both matric and osmotic control methods. For all Chroococcidiopsis strains, photosynthetic rates decreased with decreasing water potential. After 24h preincubation the decrease was linear but after 72h there was a sharp drop below-3400 kPa (a w≏0.976). In contrast, the two Chroococcus strains showed optimum photosynthesis between-3000 and-4000 KPa. It appears, therefore, that Chroococcidiopsis in deserts may have a different survival strategy in response to aridity than Chroococcus (rare in deserts). Absolute rates of 14CO2 uptake were higher in matric than in osmotic control systems. It is suggested that, in a matric experimental system, the water status is more representative of the natural conditions in arid environments. The consistent differences between different strains in their response to water stress suggest that this character in Cyanobacteria may be of taxonomic significance.
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    Salt relations of Dunaliella. Transitional changes in glycerol content and oxygen exchange reactions on water stress (1981)
    Springer
    Archives of microbiology 129 (1981), S. 154-159 
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    ISSN: 1432-072X
    Keywords: Compatible solute ; Dunaliella ; Glycerol ; Osmoregulation ; Osmotic shock ; Photosynthesis ; Respiration ; Salt stress ; Salt tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in glycerol content are reported for Dunaliella tertiolecta over an 8 h period after a salt stress or dilution stress. Under the experimental conditions, the new glycerol level was reached in about 30 min in light or dark but there was evidence of oscillations after that, particularly on dilution stress. Glycerol disappearance on dilution stress is caused predominantly by dissimilation. A salt stress immediately inhibited photosynthetic oxygen evolution and caused net oxygen uptake for a period of about 36 h after the stress. Oxygen evolution was reestablished after that and the process of recovery to the point of resumption of net evolution was not affected by conditions designed to inhibit protein synthesis. Dilution stress of comparable magnitude diminished but did not eliminate photosynthetic oxygen evolution and recovery to a pre-stress level took about 18 h. Effects of HCO 3 - concentration suggested that photorespiration was not the sole determinant of oxygen uptake induced by salt stress but it was not possible to apportion with confidence the contribution of mitochondrial and other types of respiration. There was no evidence that modification by stress of energy-induced proton fluxes across the plasma membrane constituted an osmoregulatory signal in either species.
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    The intracellular pH of isolated, photosynthetically active Asparagus mesophyll cells (1981)
    Springer
    Planta 153 (1981), S. 210-216 
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    ISSN: 1432-2048
    Keywords: Asparagus ; 5,5-Dimethyloxazolidine-2,4-dione ; Mesophyll ; Photosynthesis ; pH, intracellular
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intracellular pH of isolated, photosynthetically active mesophyll cells of Asparagus sprengeri Regel has been determined, in the light and dark, by the distribution of the weak acid 5,5-dimethyl-[2-14C]oxazolidine-2,4-dione ([14C]DMO) between the cells and the liquid medium. [14C]DMO was taken up rapidly, reaching equilibrium in 7–10 min of incubation, but was not metabolized by the cells, and intracellular binding of the compound was minimal. The intracellular pH, measured at saturating light fluence and 1.5 mM sodium bicarbonate, was found to remain relatively constant at 6.95–7.21 over the external pH range of 5.5–7.2. Illumination of the cells increased the intracellular pH compared to dark controls. The pH of the cytoplasm, excluding and including the chloroplasts (“cytoplasmic” and “bulk cytoplasmic”, respectively) was calculated from the experimentally derived intracellular [14C]DMO concentration and estimates of the vacuolar, chloroplastic and cytoplasmic volumes. The calculated cytoplasmic pH was similar in the light and dark, being 7.75 and 7.74, respectively, while the calculated pH of bulk cytoplasm was 7.85 in the light and 7.49 in the dark. Theoretical analysis indicated that intracellular pH is a good indicator of changes in the bulk cytoplasmic pH but insensitive to changes in vacuolar pH. The external pH optimum for photosynthesis (O2 evolution) of isolated Asparagus cells was pH 7.2. At pH 8.0 photosynthesis was inhibited by 30% and at pH 5.25 by 45%. Inhibition at alkaline pH may be the result of a decrease in the pH gradient between the cells and the medium, causing CO2 limitation in the cell. At acid pH, decrease in internal pH caused by substantial accumulation of inorganic carbon may account for the loss in photosynthetic activity.
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    On the dynamics of internal leaf carbon dioxide uptake (1981)
    Springer
    Journal of mathematical biology 11 (1981), S. 181-191 
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    ISSN: 1432-1416
    Keywords: Photosynthesis ; Mathematical models ; Reaction-diffusion equations ; Varying environments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A model is proposed to investigate the hypothesis that the observed time course of whole leaf photosynthetic responses to changes in incident light energy are caused by diffusional limitations. The model leaf consists of a continuously distributed mesophyll with diffusion of CO2 in the leaf interior governed by a reaction-diffusion equation. Biochemical activation is assumed to occur on a fast time scale. Both the cases of a homogeneous and a nonhomogeneous leaf interior are investigated. Using parameter estimates available in the literature, the model predicts CO2 uptake equilibration times which are much smaller than those observed. The results strongly suggest that diffusional limitations do not significantly affect photosynthetic dynamics in variable light environments.
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    The role of ‘Norin 10’ dwarfing genes in photosynthetic and respiratory activity of wheat leaves (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 81-84 
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    ISSN: 1432-2242
    Keywords: Wheat ; ‘Norin 10’ dwarfing genes ; Photosynthesis ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparative analysis of eight cultivars of spring wheat (Triticum aestivum) classified by height as tall (T), semi-dwarf (D1), dwarf (D2) and very dwarf (D3) was conducted to study their efficiency of oxygen exchange during photosynthesis and dark respiration. Two cultivars were included in each height group. Cultivars carrying ‘Norin 10’ dwarfing genes (D1, D2 and D3) were found to have a significantly higher photosynthetic rate per unit leaf area than talls (T) that lack these genes. Among the ‘Norin’ gene carriers, dwarf group (D2) was most efficient, followed by very dwarf (D3) and semi-dwarf (D1). Photosynthetic rate and respiratory rate were found to have a positive relationship.
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    Effect of phytotoxic metabolites ofFusarium culmorum on growth and physiology of barley plants (1981)
    Springer
    Plant and soil 60 (1981), S. 377-384 
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    ISSN: 1573-5036
    Keywords: Barley seedlings ; Chlorophyll ; Fusarium culmorum ; Organic acids ; Photosynthesis ; Phytotoxicity ; Transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two unidentified organic acids isolated from the culture filtrate ofFusarium culmorum, grown in glucose-limited continuous culture, produced phytotoxic effects on growth and physiology of barley seedlings. Stomatal diffusion resistance and chlorophyll content of shoots were increased, but the rate of photosynthesis per unit area of leaf did not change. Although total carbon and nitrogen composition of treated seedlings was not significantly affected, phosphorus uptake was greatly increased. Toxicity of the acids was promoted at low pH.
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    Three chloroplast membrane models corresponding to different photosynthetic potentialities in the same plant (1980)
    Springer
    Planta 149 (1980), S. 34-43 
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    ISSN: 1432-2048
    Keywords: Chloroplast membrane models ; Lipids ; Lycopersicum ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biochemical characteristics and photosynthetic activities of chloroplast membranes of the two regions of the green tomato fruit were compared to those of the leaves which were taken as controls. Membranes may have qualitatively (and even quantitatively) identical components, such as lipids and chlorophylls, and yet have different photosynthetic abilities. Three models then are proposed.
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    The role of monovalent cations for photosynthesis of isolated intact chloroplasts (1980)
    Springer
    Planta 149 (1980), S. 170-175 
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    ISSN: 1432-2048
    Keywords: Cations and photosynthesis ; Chloroplast (low-salt effects) ; Light activation (photosynthesis enzymes) ; Photosynthesis ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of monovalent cations in the photosynthesis of isolated intact spinach chloroplasts was investigated. When intact chloroplasts were assayed in a medium containing only low concentrations of mono- and divalent cations (about 3 mval l-1), CO2-fixation was strongly inhibited although the intactness of chloroplasts remained unchanged. Addition of K+, Rb+, or Na+ (50–100 mM) fully restored photosynthesis. Both the degree of inhibition and restoration varied with the plant material and the storage time of the chloroplasts in “low-salt” medium. In most experiments the various monovalent cations showed a different effectiveness in restoring photosynthesis of low-salt chloroplasts (K+〉Rb+〉Na+). Of the divalent cations tested, Mg2+ also restored photosynthesis, but to a lesser extent than the monovalent cations. In contrast to CO2-fixation, reduction of 3-phosphoglycerate was not ihibited under low-salt conditions. In the dark, CO2-fixation of lysed chloroplasts supplied with ATP, NADPH, and 3-phosphoglycerate strictly required the presence of Mg2+ but was independent of monovalent cations. This finding excludes a direct inactivation of Calvin cycle enzymes as a possible basis for the inhibition of photosynthesis under low-salt conditions. Light-induced alkalization of the stroma and an increase in the concentration of freely exchangeable Mg2+ in the stroma, which can be observed in normal chloroplasts, did not occur under low-salt conditions but were strongly enhanced after addition of monovalent cations (50–100 mM) or Mg2+ (20–50 mM). The relevance of a light-triggered K+/H+ exchange at the chloroplast envelope is discussed with regard to the light-induced increase in the pH and the Mg2+ concentration in the stroma, which are thought to be obligatory for light activation of Calvincycle enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380879
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  • 39
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    Protein deficient chloroplast ribosomes in a yellow mutant of Chlamydomonas reinhardii (1980)
    Springer
    Planta 147 (1980), S. 287-294 
    Details
    ISSN: 1432-2048
    Keywords: Chlamydomonas ; Chloroplast mutant ; Mutant (chloroplast ribosomes) ; Photosynthesis ; Ribosomes ; Ribulosebiophosphate carboxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribosomes and ribosomal proteins from wild-type and a yellow mutant of Chlamydomonas reinhardii were analyzed and compared by two-dimensional gel electrophoresis. The mixothrophically grown yellow-76 mutant differs from wild-type cells in lowered chlorophyll content and photosynthetic activity per chlorophyll unit. The latter is connected with the decreased activity of the ribulose-I,5-diphosphate-carboxylase enzyme. Analytical ultracentrifugation of cell extracts shows a normal amount of free 70S ribosomes and 50S subunit in the mutant cells. Two-dimensional gel electrophoresis shows considerable alterations in the protein composition of the 70S ribosomes of the mutant. Two proteins are absent from the electrophoretograms of the yellow-76 mutant, and seven proteins are present in reduced amounts. The genetical analysis shows a Mendelian pattern of inheritance, indicating that protein alterations presumably are localized in nuclear DNA.
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    URL: http://dx.doi.org/10.1007/BF00379835
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  • 40
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    Photosynthetic activities of a membrane preparation of the thermophilic cyanobacterium Mastigocladus laminosus (1980)
    Springer
    Archives of microbiology 124 (1980), S. 155-160 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Thylakoid membranes ; Electron transport ; Photophosphorylation ; Thermophily ; Proton uptake ; Cyanobacteria ; Matigocladus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetically active membranes have been prepared from the thermophilic cyanobacterium Mastigogladus laminosus by treatment with lysozyme. The membranes were active in electron transport through photosystem I and II as well as in photophosphorylation and proton uptake. Cells were grown at 40°, 45° and 55°C respectively. The temperature optimum of oxygen evolution of whole cells was about 10°C higher than the growth temperature. In isolated membranes the temperature optimum for cyclic photophosphorylation was identical to the growth temperature of the cells whereas the optimum for photosystem II electron transport never exceeded 40°C. Photophosphorylation was inhibited by N, N′-dicyclohexyl carbodiimide (DCCD), carbonyl-cyanide-m-chlorophenylhydrazone and NH4Cl, whereas proton uptake was enhanced by DCCD. Electron transport was slightly inhibited by these treatments. The membranes could be stored for several weeks at-20°C in 50% glycerol without any loss in the activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427721
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  • 41
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    Molecular hydrogen: A new inhibitor of photosynthesis in the blue-green alga (cyanobacterium), Anabaena sp. TA 1 (1980)
    Springer
    Archives of microbiology 126 (1980), S. 1-10 
    Details
    ISSN: 1432-072X
    Keywords: Anabaena sp. ; Nitrogenase ; H2-inhibition ; Photosynthesis ; Pigment concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molecular hydrogen strongly inhibits C2H2-reducing activity in intact cells of Anabaena sp. TA 1 in the light under anaerobic conditions. The inhibitory effect can be partially relieved by supplying the cells with molecular oxygen. When cells of Anabaena sp. TA 1 were grown under anaerobic N2-fixation conditions in the presence of 0.05 bar H2 with white light a pronounced decrease of growth rate occurred. With ammonium ions as nitrogen source the inhibitory effect of H2 was less pronounced. Concomitant with the reduced growth under N2 in the presence of H2 a loss of blue-green pigmentation was observed due to a diminished phycocyanin content. On the other hand, the concentration of carotenoids and chlorophyll remained nearly constant. With NH 4 + as nitrogen source nearly no alteration of phycocyanin content occurred upon incubation with H2. In addition, H2 induced a random distribution of thylakoid membranes in vegetative cells which normally exhibited a curved, parallel pattern. In heterocysts, however, photosynthetic membranes were always arranged randomly. Under far red light, growth and activity of photosystem II were largely diminshed. Under these conditions H2 exhibits an additional inhibitory effect. However, compared to 62% growth inhibition under white light, a decrease of only 20% occurred. Measurements of the photosynthetic electron flow with isolated thylakoid membranes showed that oxidation of diphenylcarbazide (DCP) by membranes from H2-grown cells was inhibited by 28% compared to membranes from control cells. Using ascorbate/DCPIP as electron donor an inhibition of only 1–4% was measured. It is concluded, that H2 inhibits electron flow in the photosynthetic electron transport chain at a site between photosystem II and photosystem I.
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    URL: http://dx.doi.org/10.1007/BF00421884
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  • 42
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    Autotrophic CO2 fixation in Chlorobium limicola. Evidence against the operation of the Calvin cycle in growing cells (1980)
    Springer
    Archives of microbiology 128 (1980), S. 56-63 
    Details
    ISSN: 1432-072X
    Keywords: Chlorobium limicola ; Autotrophic CO2 fixation ; Calvin cycle ; Reductive tricarboxylic acid cycle ; Pyruvate assimilation ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorobium limicola has been proposed to assimilate CO2 autotrophically via a reductive tricarboxylic acid cycle rather than via the Calvin cycle. This proposal has been a matter of considerable controversy. In order to determine which pathway is operative, the bacterium was grown on a mineral salts medium with CO2 as the main carbon source supplemented with specifically labeled 14C-pyruvate, and the incorporation of 14C into alanine (≙intracellular pyruvate), aspartate (≙oxaloacetate), glutamate (≙α-ketoglutarate), and glucose (≙hexosephosphate) was measured in exponentially growing cells in long term labeling experiments. During growth in presence of pyruvate, 20% of the cell carbon were derived from pyruvate in the medium, 80% from CO2. Since pyruvate was not oxidized to CO2, only those compounds should become labeled which were synthesized from CO2 via pyruvate. The three amino acids and glucose were found to be labeled. Alanine had one fifth the specific radioactivity of the extracellular pyruvate, indicating that 20% of the intracellular pyruvate pool were derived from pyruvate in the medium, 80% were synthesized from CO2. Glucose had twice the specific radioactivity of alanine, showing that hexosephosphate synthesis from CO2 proceeded via the pyruvate pool. The latter finding is not consistent with the operation of the Calvin cycle, in which pyruvate is not an intermediate. The specific radioactivities of aspartate (≙oxaloacetate) and of glutamate (≙α-ketoglutarate) were practically identical but considerably lower than that of alanine (≙ intracellular pyruvate). These findings are compatible with the operation of a reductive tricarboxylic acid cycle as mechanism of autotrophic CO2 fixation. Degradation studies of the cell components support this interpretation.
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    URL: http://dx.doi.org/10.1007/BF00422306
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  • 43
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    Nitrogen fixation associated with a hotspring green alga (1980)
    Springer
    Archives of microbiology 124 (1980), S. 161-167 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Photosynthesis ; Green alga ; Chl a and b ; DCMU ; Light and O2 dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A unicellular alga which can grow in the light without a combined nitrogen source was isolated from a hot spring. The cells were almost spherical, usually 5–10 μm in diameter. Absorption spectra of the watersoluble pigments and of the acetone-extracted ones revealed the existence of chlorophyll a and b and the absence of phycobilins. Thin sections examined by electron microscopy revealed an eukaryotic organization with features typical of the coccoid green algae (the Chlorococcales). Cells divided by internal cytokinesis and subsequent liberation of daughter cells from the parental wall, in a way similar to Chlorella. The alga reduced acetylene to ethylene and incorporated 15N2 into cell protoplasm when incubated in a low oxygen atmosphere. Nitrogenase activity was light-dependent, microaerophilic and thermophilic. Although the association of symbiotic nitrogen fixing prokaryotes with the cells may still be possible, any such organisms have not so far been detected.
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    URL: http://dx.doi.org/10.1007/BF00427722
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  • 44
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    The metabolic interactions between Paramecium bursaria Ehrbg. and Chlorella spec. in the Paramecium bursaria-symbiosis (1980)
    Springer
    Archives of microbiology 125 (1980), S. 291-293 
    Details
    ISSN: 1432-072X
    Keywords: Paramecium bursaria ; Chlorella spec. ; Symbiosis ; CO2-supply ; Glucose ; Photosynthesis ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rates of the photosynthetic oxygen production of the green Paramecium bursaria and of the symbiotic Chlorella spec. isolated from it were measured at various CO2-concentrations in the incubation medium. Due to the respiration of the ciliate the amount of CO2 offered to the symbiotic algae in situ is higher than in water under normal atmospheric conditions. So the algae within the symbiotic unit show a higher rate of photosynthetic oxygen production than in the isolated state and thus guarantee the supply with oxygen for the Paramecium. In the green Paramecium the rate of photosynthetic oxygen production is increased by the addition of glucose. In the dark the incubation with glucose increases the rate of respiratory oxygen consumption in alga-free Paramecium bursaria to a much greater extent than in green Paramecia.
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    URL: http://dx.doi.org/10.1007/BF00446890
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  • 45
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    Changes in ultrastructure and photosynthetic capacity withinScenedesmus obliquus mutants C-2 A′, C-6 D, and C-6 E on transfer from dark grown to illuminated conditions (1980)
    Springer
    Protoplasma 103 (1980), S. 35-54 
    Details
    ISSN: 1615-6102
    Keywords: Algal mutants ; Chlorophyll ; Greening ; Photosynthesis ; Ribosome associations ; Thylakoid development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure, pigments and photosynthetic capacities of 3 X-ray induced mutants (C-2 A′, C-6 D, and C-6 E) ofScenedesmus obliquus were studied whilst growing heterotrophically in the dark and upon transfer into the light (10,000 lux). Dark grown C-2 A′, having no photosynthetic capacity and sparse amounts of chlorophylls a and b, greened at a faster rate than mutant C-6 D which already had photosystem I activity and chlorophyll a in the dark. Ultrastructural development to the wild-type situation was similar in both, but again much faster in C-2 A′ (24 hours) than in C-6 D (48 hours). In the dark grown C-2 A′ mutant the single lamellae differed from C-6 D in that they were already perforated. In the light, membrane overlapping took place in both to form first double, and later triple, thylakoid bands. A distinct phase of association of plastid ribosomes in a whorl-like arrangement with the developing thylakoids was shown by both only during the greening process. Over a similar period, mitochondrial appressions to these plastids were observed. In the dark, mutant C-6 E resembled dark grown C-6 D and possessed considerable photosystem I activity but no carotenoids. In the light it did not green, no ultrastructural changes were apparent and the unprotected chlorophyll a was photo-oxidized. All mutants in the dark showed tubular connections, resembling but not identical with the prolamellar bodies of higher plant etioplasts. Occasionally tubular connections similar to those in the dark-grown mutants were also found in the light.
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    URL: http://dx.doi.org/10.1007/BF01276740
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  • 46
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    Metabolism of poly-\-hydroxybutyric acid in bacteroids ofRhizobium lupini in connection with nitrogen fixation and photosynthesis (1980)
    Springer
    Plant and soil 56 (1980), S. 379-390 
    Details
    ISSN: 1573-5036
    Keywords: Bacteroids ; Enzymes ; Photosynthesis ; Poly-\-hydroxybutyrate metabolism ; Rhizobium lupini ; Symbiotic nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The darkening of lupin plants grown in a sand culture on a nitrogen-free medium at a stage of initial flowering led to a sharply decreased nitrogen fixation intensity which eventually ceased. Decreased intensity of nitrogen fixation in bacteroids was accompanied by an accumulation of poly-β-hydroxybutyric acid (PHB); in the course of 10–20 h (depending upon temperature) its content increased by 2.5–3.0 times. If, following darkening, the plants were once again exposed to light, an abrupt increase of nitrogen fixation intensity was observed and a simultaneous decrease of PHB content. It has been shown that lupin's exposure to light in14CO2 atmosphere lasting 19 h resulted in the latter's incorporation into PHB, bacteroids and into the entire nodule; these processes developed almost in parallel. During the early period of vegetation growth prior to flowering, the PHB content of bacteroids decreased from 13–14 to 3–4% of dry weight, whereas the intensity of nitrogen fixation was raised. Concurrently increase of the activity of some enzymes connected with the PHB metabolism (acetoacetyl-CoA-reductase, acetyl-CoA-acetyl transferase, PHB-depolymerase, CoA-transferase of 3-ketoacids) occured. The plants' subsequent ageing and reduction of nitrogen fixation intensity led to a noticeable increase of PHB content and a decrease of the above mentioned enzymes' activity. The specific activity of \-hydroxybutyric dehydrogenase involved with PHB catabolism was high and was maintained at a constant level throughout the entire vegetative period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02143032
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