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  • Cyanobacteria  (26)
  • Springer  (26)
  • Elsevier
  • National Academy of Sciences
  • 1985-1989  (26)
  • 1950-1954
  • 1985  (26)
Collection
Keywords
Publisher
Years
  • 1985-1989  (26)
  • 1950-1954
Year
  • 1
    Electronic Resource
    Electronic Resource
    Phylogeny of the 5S ribosomal RNA fromSynechococcus lividus II: The cyanobacterial/chloroplast 5S RNAs form a common structural class (1985)
    Springer
    Journal of molecular evolution 21 (1985), S. 334-337 
    Details
    ISSN: 1432-1432
    Keywords: 5S RNA ; Cyanobacteria ; Phylogeny ; Sequence ; Secondary structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The complete nucleotide sequence of the 5S ribosomal RNA from the cyanobacteriumSynechococcus lividus II has been determined. The sequence is 5′-UGCCUAGUGUUUAUGGCGCG-GUGGAACCACGCUGAUCCAUCCCGAACUC-AGAGGUGAAACAUCGCAGCGGUGAAGAU-AGUUGGAGGGUAGCCUCCUGCAAAAAUA-GCUCAAUGCUAGGCAOH-3′. This 5S RNA has the cyanobacterial- and chloroplast-specific nucleotide insertion between positions 30 and 31 (using the numbering system of the generalized eubacterial 5S RNA) and the chloroplast-specific nucleotide-deletion signature between positions 34 and 39. The 5S RNA ofS. lividus II has 27 base differences compared with the 5S RNA of the related strainS. lividus III. This large difference may reflect an ancient divergence between these two organisms. The electrophoretic mobilities on nondenaturing polyacrylamide gels of renatured 5S RNAs fromS. lividus II,S. lividus III, and spinach chloroplasts are identical, but differ considerably from that ofEscherichia coli 5S RNA. This most likely reflects differences in higher-order structure between the 5S RNA ofE. coli and these cyanobacterial and chloroplast 5S RNAs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02115651
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  • 2
    Electronic Resource
    Electronic Resource
    Immuno-gold localization of glutamine synthetase in a nitrogen-fixing cyanobacterium (Anabaena cylindrica) (1985)
    Springer
    Planta 166 (1985), S. 329-334 
    Details
    ISSN: 1432-2048
    Keywords: Anabaena ; Cyanobacteria ; Glutamine synthetase ; Immuno-gold localization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Localization of glutamine synthetase in thin sections of nitrogen-fixing Anabaena cylindrica was performed using immuno-gold/transmission electronmicroscopy. The enzyme was present in all of the three cell types possible; vegetative cells, heterocysts and akinetes. The specific gold label was always more pronounced in heterocysts compared with vegetative cells, and showed a uniform distribution in all three types. No specific label was associated with subcellular inclusions such as carboxysomes, cyanophycin granules and polyphosphate granules. When anti-glutamine synthetase antiserum was omitted, no label was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401169
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  • 3
    Electronic Resource
    Electronic Resource
    Interaction between photosynthetic and respiratory electron-transfer chains in the membranes of Anabaena variabilis (1985)
    Springer
    Planta 166 (1985), S. 182-186 
    Details
    ISSN: 1432-2048
    Keywords: Anabaena ; Cyanobacteria ; Electron transport ; Photosynthesis and respiration ; Respiration and photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rate of CO2- and p-benzoquione-dependent photosynthetic O2 evolution by Anabaena variabilis cells remained unaltered and the rate of O2 uptake observed after switching off the light (endogenous respiration) was enhanced by a factor of 6–8 when the O2 concentration was increased from 200 to 400 μM. Photosystem-I-linked O2 uptake and respiration of the cells incubated with ascorbate and N,N,N′N′-tetramethyl-p-phenylenediamine was not appreciable influenced by the O2 concentration. 2-Iodo-6-isopropyl-3-methyl-2′,4,4′-trinitrodiphenyl ether, blocking electron transfer at the plastoquinone level, suppressed O2 evolution and had no influence on endogenous respiration. 2-n-Heptyl-4-hydroxyquinoline-N-oxide, an inhibitor of electron transfer between photosystems II and I, as well as the cytochrome-oxidase inhibitors N 3 - , CN- and NH2OH, caused a 35–50% retardation of endogenous respiration and blocked photosynthetic O2 evolution. The molar ratio of cytochromes b6, f, c-553, aa3 and photosystem-I reaction centers in the isolated membranes equalled approx. 2:1:2:0.7:2. It is inferred that endogenous respiration of A. variabilis cells is inhibited by the light-induced electron flow through both photosystems at the level of the plastoquinone-plastocyanin-oxidoreductase complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397346
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  • 4
    Electronic Resource
    Electronic Resource
    Osmotic adjustment in Spirulina platensis (1985)
    Springer
    Planta 163 (1985), S. 424-429 
    Details
    ISSN: 1432-2048
    Keywords: Cyanobacteria ; Glucosyl-glycerol ; Osmotic adjustment ; Spirulina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The filamentous cyanobacterium Spirulina platensis has been examined for salt tolerance and osmotic adjustment. Salinities up to 150% seawater had little effect on growth yield or photosynthetic O2 evolution; higher salinities were markedly inhibitory. Osmotic adjustment was achieved by the intracellular accumulation of the low-molecular-weight carbohydrate glucosyl-glycerol in response to increased external salinity: in fullstrength (100%) seawater glucosyl-glycerol accounted for approximately 5.0% of the dry weight of the cyanobacterium. Trehalose was also present, particularly in cells at low salt concentration, and in 50% seawater medium accounted for up to 1.0% of the dry weight of the cyanobacterium. For cells grown in 100% seawater the ratio of trehalose to glucosyl-glycerol varied with temperature: at 37°C trehalose comprised 31% (w/w) of the low-molecular-weight carbohydrates while at 20°C only 9% of the total was trehalose. When subjected to hypo-osmotic shock the intracellular concentration of glucosyl-glycerol decreased and this was mirrored by an increase in glycogen. An understanding of the osmotic adjustment of S. platensis has implications both for the mass culturing of this and other strains of Spirulina and possibly also for the quality of the harvested product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395153
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of temperature and light on the toxicity and growth of the blue-green alga Microcystis aeruginosa (UV-006) (1985)
    Springer
    Planta 163 (1985), S. 55-59 
    Details
    ISSN: 1432-2048
    Keywords: Cyanobacteria ; Light and toxicity ; Microcystis ; Temperature and toxicity ; Toxicity (cyanobacterium)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The toxicity and growth of Microcystis aeruginosa (UV-006) from the Hartbeespoort Dam, South Africa were investigated at different temperatures and photon fluence rates under laboratory conditions. Cells harvested in late logarithmic growth phase were most toxic when grown at 20°C (LD50) median lethal dose [IP, mouse]=25.4 mg kg-1). Toxicity was markedly reduced at growth temperatures above 28° C. Fluence rate had a smaller effect on the toxicity of the cells, but toxicity tended to be less at the very low and high light fluences. Optimal conditions for growth did not coincide with those for toxin production. Well-aerated cultures of this isolate kept at pH 9.5 by CO2 addition, a temperature of 20–24° C, a fluence rate of 145 μmol photons m-2 s-1 and harvested in the late logarithmic growth phase yielded the maximum quantity of toxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395897
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  • 6
    Electronic Resource
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    Evidence of β-carotene 7,8(7′,8′) oxygenase (β-cyclocitral, crocetindial generating) in Microcystis (1985)
    Springer
    Archives of microbiology 141 (1985), S. 337-343 
    Details
    ISSN: 1432-072X
    Keywords: β-Carotene oxygenase ; β-Cyclocitral ; Crocetindial ; 18O2 Labelling ; Microcystis ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A β-carotene oxygenase is described which occurs in the Cyanobacterium Microcystis. It cleaves β-carotene and zeaxanthin specifically at the positions 7,8 and 7′,8′, while echinenone and myxoxanthophyll are not affected. The oxidative cleavage of β-carotene leads to the formation of β-cyclocitral and crocetindial and that of zeaxanthin to hydroxy-β-cyclocitral and crocetindial in nearly stoichiometric amounts. Oxidant is dioxygen as has been demonstrated by high incroporation (86%) of 18O2 into β-cyclocitral. β-Carotene oxygenase is membrane bound, sensitive to sulfhydryl reagents, antioxidants and chelating agents. Iron seems to be an essential part of the enzyme activity. Cofactors necessary for the reaction could not be detected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428846
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  • 7
    Electronic Resource
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    Assimilation of exogenous and dinitrogen-derived13NH 4 + byAnabaena azollae separated fromAzolla caroliniana Willd (1985)
    Springer
    Archives of microbiology 142 (1985), S. 229-233 
    Details
    ISSN: 1432-072X
    Keywords: Ammonium assimilation ; Excretion ; Anabaena azollae ; Azolla caroliniana ; Cyanobacteria ; Glutamine ; Glutamate formation ; Nitrogen fixation ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Anabaena azollae was isolated fromAzolla caroliniana by the “gentle roller” method and differential centrifugation. Incubation of suchAnabaena preparations for 10 min with [13N]N2 resulted in the formation of four radioactive compounds; ammonium, glutamine, glutamate and alanine. Ammonium accounted for 66% of the total radioactivity recovered and 58% of the ammonium was in an extracellular fraction. Since essentially no extracellular13N-labeled organic compounds were found, it appears that ammonium is the compound most probably made available toAzolla during dinitrogen-dependent growth of the association. The kinetics of incorporation of exogenous13NH 4 + into glutamine and glutamate were characteristic of a precursor (glutamine)-product (glutamate) relationship and consistent with assimilation by the glutamine synthetase-glutamate synthase pathway. The results of experiments using the glutamine synthetase inhibitor, methionine sulfoximine, the glutamate synthase inhibitor, diazo-oxonorleucine, and increasing the ammonium concentration to greater than 1 mM, provided evidence for assimilation primarily by the glutamine synthetase-glutamate synthase pathway with little or no contribution from biosynthetic glutamate dehydrogenase. While showing that N2 fixation and NH 4 + assimilation were not tightly coupled metabolic processes in symbioticAnabaena, these results reflect a composite picture and do not indicate the extent to which ammonium assimilatory enzymes might be regulated in filaments associated with specific stages in theAzolla-Anabaena developmental profile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00693395
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  • 8
    Electronic Resource
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    Pathways of hydrogen uptake in the cyanobacterium Nostoc muscorum (1985)
    Springer
    Archives of microbiology 142 (1985), S. 349-353 
    Details
    ISSN: 1432-072X
    Keywords: Hydrogen uptake ; Hydrogenase and nitrogenase activity (cellular, cell-free) ; Photosynthetic oxygen evolution ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two pathways of hydrogen uptake in Nostoc muscorum are apparent using either oxygen or nitrogen as electron acceptor. Hydrogen uptake (under argon with some oxygen as electron acceptor assayed in the dark; oxyhydrogen reaction) is found to be more active in dense, light-limited cultures than in thin cultures when light is not limiting. Addition of bicarbonate inhibits this hydrogen uptake, because photosynthesis is stimulated. In a cell-free hydrogenase assay, a 10-fold increase of the activity can be measured, after the cells having been kept under lightlimiting conditions. After incubation under light-saturating conditions, no hydrogen uptake is found, when filaments are assayed under argon plus some oxygen. Assaying these cells under a nitrogen atmosphere, a strong hydrogen uptake occurs. The corresponding cell-free hydrogenase assay exhibits low hydrogenase activity. Furthermore, the hydrogen uptake by intact filaments under nitrogen in the light apparently is correlated with nitrogenase activity. These studies give evidence that, under certain physiological conditions, hydrogen uptake of heterocysts proceeds directly via nitrogenase, with no hydrogenase involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00491902
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  • 9
    Electronic Resource
    Electronic Resource
    Oxygen protection of nitrogenase in the aerobically nitrogen fixing, non-heterocystous cyanobacterium Oscillatoria sp. (1985)
    Springer
    Archives of microbiology 143 (1985), S. 72-76 
    Details
    ISSN: 1432-072X
    Keywords: Oscillatoria ; Cyanobacteria ; Nitrogen fixation ; Oxygen protection of N2-ase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oscillatoria sp. strain 23 is a filamentous, non-heterocystous cyanobacterium that fixes nitrogen aerobically. Although, in this organism nitrogenase is inactivated by oxygen a high tolerance is observed. Up to a pO2 of 0.15 atm, oxygen does not have any measurable effects on acetylene reduction. Higher concentrations of oxygen inhibited the activity to a relatively high degree. Evidence for two mechanisms of oxygen protection of nitrogenase in this cyanobacterium was obtained. A high rate of synthesis of nitrogenase may allow the organism to maintain a certain amount of active enzyme under aerobic conditions. Secondly, a switch off/on mechanism may reversibly convert the active enzyme into a non-active form which is insensitive to oxygen inactivation after a sudden and short-term exposure to high oxygen concentrations. It is conceived that these mechanisms in addition to a temporal separation of nitrogen fixation from oxygenic photosynthesis sufficiently explain the regulation process of aerobic nitrogen fixation in this organism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414771
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  • 10
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    Nitrogenase activity in the non-heterocystous cyanobacterium Oscillatoria sp. grown under alternating light-dark cycles (1985)
    Springer
    Archives of microbiology 143 (1985), S. 67-71 
    Details
    ISSN: 1432-072X
    Keywords: Oscillatoria ; Cyanobacteria ; Nitrogen fixation ; Light-dark cycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The non-heterocystous cyanobacterium Oscillatoria sp. strain 23 fixes nitrogen under aerobic conditions. If nitrate-grown cultures were transferred to a medium free of combined nitrogen, nitrogenase was induced within about 1 day. The acetylene reduction showed a diurnal variation under conditions of continuous light. Maximum rates of acetylene reduction steadily increased during 8 successive days. When grown under alternating light-dark cycles, Oscillatoria sp. fixes nitrogen preferably in the dark period. For dark periods longer than 8 h, nitrogenase activity is only present during the dark period. For dark periods of 8 h and less, however, nitrogenase activity appears before the beginning of the dark period. This is most pronounced in cultures grown in a 20 h light – 4 h dark cycle. In that case, nitrogenase activity appears 3–4 h before the beginning of the dark period. According to the light-dark regime applied, nitrogenase activity was observed during 8–11 h. Oscillatoria sp. grown under 16 h light and 8 h dark cycle, also induced nitrogenase at the usual point of time, when suddenly transferred to conditions of continuous light. The activity appeared exactly at the point of time where the dark period used to begin. No nitrogenase activity was observed when chloramphenicol was added to the cultures 3 h before the onset of the dark period. This observation indicated that for each cycle, de novo nitrogenase synthesis is necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414770
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  • 11
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    A simple and rapid method for screening bacteria for type II restriction endonucleases: enzymes in Aphanothece halophytica (1985)
    Springer
    Archives of microbiology 141 (1985), S. 70-74 
    Details
    ISSN: 1432-072X
    Keywords: Restriction-modification ; Site-specific endonuclease ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method is described which allows a large number of bacterial strains to be rapidly and easily screened for the presence of site-specific endonucleases. The method involves selective permeabilization of the bacterial cell and analysis of the exuded material. Type II restriction endonucleases from cyanobacteria and Gram-negative eubacteria have been detected and new enzymes have been found. The method should be widely applicable and easy to modify for use in genera other than those tested. Three-site-specific endonuclease activities, detected by this method in Aphanothece halophytica PCC 7412, were purified and their recognition and cleavage specificities were determined AhaI and AhaII recognise and cleave the same DNA sequences as CauII and AcyI respectively; the specificity of AhaIII (TTT↓AAA) has been reported previously (Whitehead and Brown, 1982, FEBS Letters 143:296–300).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446742
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  • 12
    Electronic Resource
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    Modes of proton translocation across the cell membrane of respiring cyanobacteria (1985)
    Springer
    Archives of microbiology 141 (1985), S. 330-336 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Proton translocation ; Cell membrane ; Respiratory chain ; F0F1-ATPase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acidification of weakly buffered suspensions of the cyanobacteria Anacystis nidulans, Nostoc sp. strain MAC, Dermocarpa sp. and Anabaena variabilis was observed after the application of oxygen pulses to anaerobic cells. The acidification was caused by proton extrusion from the oxygen pulsed cells since it was eliminated by the uncoupler (H+ ionophore) carbonyl cyanide m-chlorophenylhydrazone. Results with the inhibitors dicyclohexylcarbodiimide or 7-chloro-4-nitrobenz-2-oxa-1,3-diazole, orthovanadate and cyanide indicated the association of various fractions of the observed proton extrusion with different activities of the cell membrane, viz. a H+-translocating reversible F0F1-ATPase, a unidirectional H+-translocating ATP hydrolase, and a respiratory electron transport system, respectively. Further parameters investigated were the pH dependence and the H+/O stoichiometry of the H+ extrusion from oxygen pulsed cyanobacteria. H+/O ratios at neutral pH were between 4 (Anacystis nidulans) and 0.3 (Dermocarpa) with uninhibited, actively phosphorylating cells and between 2 (Anacystis nidulans) and 0.4 (Dermocarpa) with ATPase-inhibited (ATP-depleted) cells, respectively. It is significant that with all four cyanobacteria tested a major fraction of the observed H+ ejection remained unaffected by ATPase inhibitors even at concentration which completely abolished all oxidative phosphorylation. Vanadate had a major effect on the H+ extrusion from Anabaena only. From this it is concluded that in the cyanobacterial species investigated part of the H+ extrusion from oxygen pulsed cells is directly linked to some H+-translocating respiratory electron transport chain present in the cell membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428845
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  • 13
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    Modulation of cell surface hydrophobicity in the benthic cyanobacterium Phormidium J-1 (1985)
    Springer
    Archives of microbiology 142 (1985), S. 21-27 
    Details
    ISSN: 1432-072X
    Keywords: Cell-surface modulation ; Hydrophobicity ; Cyanobacteria ; Phormidium J-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A shift from cell-surface hydrophobicity to hydrophilicity was experimentally induced in the benthic hydrophobic cyanobacterium Phormidium sp. strain J-1, by mechanical shearing, chloramphenicol, and proteolytic treatment after preincubation with sodium dodecyl sulfate (SDS). Treatment with SDS alone, while releasing large amounts of protein and carbohydrates from the cell wall, did not affect cell surface hydrophobicity. Ultrastructural analysis showed the cells, to be enveloped by a double-layered minicapsule. Treatments affecting cellsurface hydrophobicity also caused changes in capsular components. A model, describing cell-surface structure, composition and properties in Phormidium J-1, was constructed by correlating ultrastructural data with surface properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409231
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  • 14
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    Electron donation to nitrogenase in heterocysts of cyanobacteria (1985)
    Springer
    Archives of microbiology 143 (1985), S. 185-191 
    Details
    ISSN: 1432-072X
    Keywords: Heterocyst ; Pyruvate: ferredoxin oxidoreductase ; Nitrogen fixation ; Electron transport to nitrogenase ; Ferredoxin ; Cyanobacteria ; Anabaena cylindrica ; Anabaena variabilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Various electron donors were found to stimulate C2H2 reduction (N2 fixation) by isolated heterocysts from Anabaena variabilis and Anabaena cylindrica. Intermediates of glycolysis and the tricarboxylic acid cycle as well as unphosphorylated sugars like glucose, fructose and erythrose were among these electron donors. The transfer of electrons from donors like H2, NADH, glyoxylate and glycollate was strictly light-dependent, whereas others like NADPH or pyruvate plus coenzyme A supported C2H2 reduction also in the dark. In all cases, the overall activity was enhanced by light. The stimulation by light was more distinct with heterocysts from A. variabilis than with heterocysts from A. cylindrica. The present communication establishes that pyruvate supports C2H2 reduction by heterocysts from either A. variabilis or A. cylindrica with rates comparable to those with other electron donors. Pyruvate could, however, support C2H2 reduction only in the presence of coenzyme A, and the concentrations of both coenzyme A and pyruvate were crucial. A pyruvate-dependent reduction of ferredoxin by extracts from heterocysts was recorded spectrophotometrically. Glyoxylate, which is an inhibitor of thiamine pyrophosphate-dependent decarboxylations, inhibited pyruvate-dependent C2H2 reduction. This result supports the conclusion that pyruvate is metabolised by pyruvate: ferredoxin oxidoreductase in heterocysts. High concentrations of pyruvate and other electron donors inhibited C2H2 reduction which suggests that nitrogenase activity in heterocysts may be controlled by the availability of electron donors.
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    URL: http://dx.doi.org/10.1007/BF00411045
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  • 15
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    Inhibition of nitrate utilization by amino acids in intact Anacystis nidulans cells (1985)
    Springer
    Archives of microbiology 142 (1985), S. 1-5 
    Details
    ISSN: 1432-072X
    Keywords: Anacystis nidulans ; Cyanobacteria ; Amino acids ; Nitrate utilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In an attempt to establish the nature of the ammonium-assimilation products which mediate the inhibition by ammonium of nitrate uptake in cyanobacteria, the effect of different amino acids on nitrate utilization by intact Anacystis nidulans cells has been assayed. To exclude an indirect inhibition of nitrate uptake through the ammonium which the amino acids might release, the cells were pretreated with l-methionine-d,l-sulfoximine (MSX), a potent inactivator of glutamine synthetase. Under these conditions, several l-amino acids, but not the corresponding d-isomers, affected nitrate utilization to a variable extent, causing inhibitions ranging between 20 and 80% when added at 20 mM concentration. For most of the inhibitory amino acids, including l-isoleucine, l-leucine and l-valine, a correlation was found between their ability to act as amino group donors to α-ketoglutarate, in reactions catalyzed by A. nidulans cell-free extracts, and their inhibitory effect on nitrate utilization. l-Glutamine, l-asparagine and glycine, being effective inhibitors of nitrate utilization, were poor substrates for the transaminating activity to α-ketoglutarate, however. The possible role of the latter amino acids as mediators in the ammonium-promoted inhibition of nitrate uptake is discussed.
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    URL: http://dx.doi.org/10.1007/BF00409227
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  • 16
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    A model of the phototactic reaction chain of the cyanobacterium Anabaena variabilis (1985)
    Springer
    Archives of microbiology 142 (1985), S. 180-184 
    Details
    ISSN: 1432-072X
    Keywords: Anabaena variabilis ; Cyanobacteria ; Cyanophyceae ; Phototaxis ; Singlet oxygen ; Carotenoids ; Furan derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hypothesis has been proposed that in Anabaena variabilis the phototactic reaction sign is regulated by an unknown reaction sign reversal generator which is controlled by the intracellular level of singlet molecular oxygen (1O2). This hypothesis is supported by the following findings presented in this paper: Gassing with N2 and Ar shifts the phototactic transition point at which the positive reaction becomes negative to higher fluence rates. Surprisingly this is true also for gassing with molecular oxygen 3O2. Since 1O2 is produced in photosynthesis, the availability of external molecular oxygen seems not to be important. Apparently, a stream of any gas which is fast enough to remove 1O2 from the surface of the Anabaena trichomes decreases the internal 1O2 concentration and this way acts on the reaction sign reversal generator. Moreover, several carotenoids such as the water-soluble crocetin and preparations of solubilized β-carotene, canthaxanthine and the C30-ester ethyl-β-apo-8′-carotenoate shift the transition point of phototaxis to higher fluence rates by about one order of magnitude. Several tested furan derivatives, such as dimethylfuran, diphenylisobenzofuran, and furfuryl ethanol, are either cytotoxic or not water-soluble at the concentrations necessary for an effective 1O2 quenching. Based one these results a model of the phototactic reaction chain of A. variabilis is proposed.
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    URL: http://dx.doi.org/10.1007/BF00447064
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  • 17
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    Comparison of Photosystem-I and Photosystem-II activities of spheroplasts from normal and photobleached Anabaena cylindrica (1985)
    Springer
    Archives of microbiology 141 (1985), S. 112-115 
    Details
    ISSN: 1432-072X
    Keywords: Anabaena cylindrica ; Cyanobacteria ; Photochemical activity ; Energy transfer ; Functional condition of photosystems ; Carotenoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The analysis of photochemical activities of Photosystem I and Photosystem II in spheroplasts from normal and photobleached Anabaena cylindrica showed an increase in Photosystem II activity relative to Photosystem I in photobleached cells. We suggest that the reasons for this modification in photochemical activity are, (i) a rearrangement of pigments between the two photosystems, and (ii) improved functional condition of the photosynthetic units in Photosystem II.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00423269
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  • 18
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    Changes in turgor pressure in response to increases in external NaCl concentration in the gas-vacuolate cyanobacterium Microcystis sp. (1985)
    Springer
    Archives of microbiology 143 (1985), S. 290-296 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Turgor pressure ; Salt shock ; Turgor regulation ; K+ uptake, Microcystis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in cell turgor pressure have been followed in cells of Microcystis sp. transferred to culture medium containing added NaCl at osmolalities of 30–1,500 mosmol kg-1 (≡ 74–3,680 kPa). Upon upshock turgor decreased, due to osmotically-induced water loss from the cell. However, partial recovery of turgor was then observed in illuminated cells, with maximum turgor regain in media containing 30–500 mosmol kg-1 NaCl. The lightdependent recovery of turgor pressure was completed within 60 min, with no evidence of further changes in cell turgor up to 24 h. This is the first direct evidence that turgor regulation may occur in a prokaryotic organism. Short-term increases in cell K+ content were also observed upon upshock in NaCl, indicating that turgor regain may involve a turgorsensitive K+ uptake system. Estimation of internal K+ concentration in cells transferred to 250 mosmol kg-1 NaCl showed that changes in cell K+ may account for at least half of the observed turgor regain up to 60 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411252
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  • 19
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    Regulation of nitrogenase levels in Anabaena sp. ATCC 33047 and other filamentous cyanobacteria (1985)
    Springer
    Archives of microbiology 141 (1985), S. 105-111 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia ; Anabaena ; Cyanobacteria ; Nitrogen fixation ; Nitrogenase ; Nostoc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Incubation in the dark of photoautotrophically grown N2-fixing heterocystous cyanobacteria leads to a loss of nitrogenase activity. Original levels of nitrogenase activity are rapidly regained upon re-illumination of the filaments, in a process dependent on de novo protein synthesis. Ammonia, acting indirectly through some of its metabolic derivatives, inhibits the light-promoted development of nitrogenase activity in filaments of Anabaena sp. ATCC 33047 and several other cyanobacteria containing mature heterocysts. The ammonia-mediated control system is also operative in N2-fixing filaments in the absence of any added source of combined nitrogen, with the ammonia resulting from N2-fixation already partially inhibiting full expression of nitrogenase. High nitrogenase levels, about two-fold higher than those in normal N2-fixing Anabaena sp. ATCC 33047, are found in cell suspensions which have been treated with the glutamine synthetase inhibitor l-methionine-d,l-sulfoximine or subjected to nitrogen starvation. Filaments treated in either way are insensitive to the ammonia-promoted inhibition of nitrogenase development, although this insensitivity is only transitory for the nitrogen-starved filaments, which become ammonia-sensitive once they regain their normal nitrogen status.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00423268
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  • 20
    Electronic Resource
    Electronic Resource
    Unsaturated fatty acid composition and biosynthesis in Oscillatoria limnetica and other cyanobacteria (1985)
    Springer
    Archives of microbiology 141 (1985), S. 138-142 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Oscillatoria limnetica ; Polyunsaturated fatty acids ; Anoxygenic photosynthesis ; Anaerobic growth ; Hydrophobicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A number of cyanobacteria showing a high degree of adaptation to life under reduced oxygen tensions as witnessed by their potency of facultative anoxygenic CO2 photoassimilation with sulfide as electron donor were found to lack polyunsaturated fatty acids in their lipids. Lack of polyunsaturated fatty acids was found in representatives of different taxonomic groups. One of the strains lacking polyenoic acids was Oscillatoria limnetica, which can alternatively grow acrobically or anaerobically with sulfide as electron donor. This organism was found to synthesize monounsaturated fatty acids by desaturation of their saturated counterparts, in the presence as well as in the absence of molecular oxygen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00423274
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  • 21
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    Sensitivity of Nostoc commune UTEX 584 (Cyanobacteria) to water stress (1985)
    Springer
    Archives of microbiology 141 (1985), S. 51-56 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Immobilised cells ; Desiccation ; Water stress ; Nitrogenase ; ATP pool ; Photooxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cells of Nostoc commune UTEX 584 from liquid cultures expressed an upshift in nitrogenase activity when immobilised on inert supports and exposed to matric water potentials between -1.10 and -99.5 MPa. Cells incubated at 0.10 MPa (aw=c 1.0) maintained increased activity for at least 48 h following immobilization. At water potentials below -23.1 MPa (aw=0.85), the upshift was transitory. Nitrogenase activity decreased rapidly when immobilised cells were incubated at lower values of ψm. Desiccated cells stored at -99.5 MPa (aw=0.50) underwent an upshift in nitrogenase activity, and in the size of the intracellular ATP pool, when rewetted with either distilled water or liquid MBo medium (ψo =-0.18 MPa). The upshift in nitrogenase activity was chloramphenicol-sensitive and was preceeded by a lag. The duration of the lag depended on the time taken to equilibrate cells to-99.5 MPa, the time desiccated, and the conditions of storage and rewetting. Cells that had no, or very low, nitrogenase activity when rewetted in air, showed a marked stimulation of nitrogenase activity in the presence of 5% v/v CO2 under both aerobic and anerobic conditions. When rewetted in the presence of 1% w/v glucose (ψo =-0.14 MPa), vegetative cells remained intact, but heterocysts underwent autolysis and nitrogenase activity was not detected, even in the presence of 5% v/v CO2.
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    URL: http://dx.doi.org/10.1007/BF00446739
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  • 22
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    Ethylenediamine uptake and metabolism in the cyanobacterium Anabaena variabilis (1985)
    Springer
    Archives of microbiology 141 (1985), S. 244-248 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia analogues ; Anabaena variabilis ; Cyanobacteria ; Ethylenediamine ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cyanobacterium Anabaena variabilis showed a pH dependent uptake of ethylenediamine. No uptake of ethylenediamine was detected at pH 7.0. At higher pH values (e.g. pH 8.0 and pH 9.0) accumulation did occur and was attributed to diffusion of uncharged ethylenediamine in response to a pH gradient. A biphasic pattern of uptake was observed at these higher pH values. Treatment with l-methionine-d,l-sulphoximine (MSX) to inactivate glutamine synthetase (GS) inhibited the second slower phase of uptake without any significant alteration of the initial uptake. Therefore for sustained uptake, metabolism of ethylenediamine via GS was required. NH 4 + did not alter the uptake of ethylenediamine. Ethylenediamine was converted in the second phase of uptake to an analogue of glutamine which could not be detected in uptake experiments at pH 7.0 or in uptake experiments at pH 9.0 following pretreatment of cells with MSX. Ethylenediamine treatment inhibited nitrogenase activity and this inhibition was greatest at high pH values.
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    URL: http://dx.doi.org/10.1007/BF00408066
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  • 23
    Electronic Resource
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    Akinetes of the cyanobacteriumNostoc PCC 7524: morphological changes during synchronous germination (1985)
    Springer
    Archives of microbiology 142 (1985), S. 269-274 
    Details
    ISSN: 1432-072X
    Keywords: Nostoc ; Akinetes ; Germination ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Following dilution into fresh medium in the light, akinetes ofNostoc PCC 7524 germinated synchronously. Synchrony was maintained at a high level during the first 24 h, at which time the young filaments were composed either of three cells (with N2 as nitrogen source) or four cells (with NO 3 - or NH 4 + ), and at a slightly lower level during the next 24 h of growth. The pattern of cell division was similar in media containing the different nitrogen sources although the timing of the major events varied. In the presence of N2 or NO 3 - , heterocysts differentiated synchronously; the first developed invariably from a terminal cell of the young filament at approximately 19 h, the second from the other terminal cell after further vegetative cell division. Heterocyst differentiation did not occur in the presence of NH 4 + . In the absence of nitrogen (gas phase argon: CO2) akinete germination initially followed the same pattern as that observed in N2, this early stage probably occurring at the expense of intracellular reserve materials. During germination, a new laminated layer, similar in structure and position to that found in the heterocyst envelope, appeared in the akinete envelope. This layer was not present in the germinating akinetes of a mutant which was incapable of forming heterocysts.
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    URL: http://dx.doi.org/10.1007/BF00693402
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  • 24
    Electronic Resource
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    Fixation of [13N]N2 and transfer of fixed nitrogen in the Anthoceros-Nostoc symbiotic association (1985)
    Springer
    Planta 164 (1985), S. 406-414 
    Details
    ISSN: 1432-2048
    Keywords: Ammonia/ammonium (assimilation, excretion) ; Anthoceros ; Bryophyta ; Cyanobacteria ; Nitrogen fixation ; Nostoc ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The initial product of fixation of [13N]N2 by pure cultures of the reconstituted symbiotic association between Anthoceros punctatus L. and Nostoc sp. strain ac 7801 was ammonium; it accounted for 75% of the total radioactivity recovered in methanolic extracts after 0.5 min and 14% after 10 min of incubation. Glutamine and glutamate were the primary organic products synthesized from [13N]N2 after incubation times of 0.5–10 min. The kinetics of labeling of these two amino acids were characteristic of a precursor (glutamine) and product (glutamate) relationship. Results of inhibition experiments with methionine sulfoximine (MSX) and diazo-oxonorleucine were also consistent with the assimilation of N2-derived NH 4 + by Anthoceros-Nostoc through the sequential activities of glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.7.1), with little or no assimilation by glutamate dehydrogenase (EC 1.3.1.3). Isolated symbiotic Nostoc assimilated exogenous 13NH 4 + into glutamine and glutamate and their formation was inhibited by MSX, indicating operation of the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway: However, relative to free-living cultures, isolated symbiotic Nostoc assimilated 80% less exogenous ammonium into glutamine and glutamate, implying that symbiotic Nostoc could assimilate only a fraction of N2-derived NH 4 + . This implication was tested by using Anthoceros associations reconstituted with wild-type or MSX-resistant strains of Nostoc incubated with [13N]N2 in the presence of MSX. The results of these experiments indicated that, in situ, symbiotic Nostoc assimilated about 10% of the N2-derived NH 4 + and that NH 4 + was made available to Anthoceros tissue where it was apparently assimilated by the GS-GOGAT pathway. Since less than 1% of the fixed N2 was lost to the suspension medium, it appears that transfer of NH 4 + from symbiont to host tissue was very efficient in this extracellular symbiotic association.
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    URL: http://dx.doi.org/10.1007/BF00402954
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  • 25
    Electronic Resource
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    Blue-green algae (cyanobacteria): prospects and perspectives (1985)
    Springer
    Plant and soil 89 (1985), S. 97-106 
    Details
    ISSN: 1573-5036
    Keywords: Blue-green algae ; Cyanobacteria ; Osmotic responses ; Salinity tolerance ; Spirulina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Photosynthetic, prokaryotic blue-green algae (cyanobacteria) occur in a wide range of natural habitats of diverse ionic composition and as such, represent an important source of biological material for biosolar energy conversion programs using saline water. The gasvacuolate, filamentous Spirulina is grown in ‘seminatural’ culture in Lake Texcoco, Mexico, as a major source of single-cell protein for animal nutrition. Pilot-scale trials in other areas of the world have also demonstrated the suitability of blue-green algae, including Spirulina, for growth under brackish conditions. The carbohydrate accumulation profiles of blue-green algae differ in isolates from freshwater, marine and hypersaline habitats, with a trend towards sucrose or trehalose accumulation in stenohaline freshwater strains grown in media containing NaCl, while euryhaline and marine forms frequently accumulate glucosylglycerol. Many halotolerant isolates from hypersaline habitats accumulate glycinebetaine in response to osmotic stress. This knowledge may provide scope for future improvement in the N2 fixation rates of blue-green algae in saline media, using betaine-accumulating N2-fixing strains in preference to other, saltsensitive isolates.
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    URL: http://dx.doi.org/10.1007/BF02182236
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  • 26
    Electronic Resource
    Electronic Resource
    Cyanobacterial biomass production in saline media (1985)
    Springer
    Plant and soil 89 (1985), S. 107-116 
    Details
    ISSN: 1573-5036
    Keywords: Cyanobacteria ; Ferredoxin-NADP reductase ; Malate dehydrogenase ; Respiration ; Salt tolerance ; Spirulina subsalsa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The cultivation, growth patterns, and physiological activities of the marine cyanobacterium (blue-green alga)Spirulina subsalsa were studied. A comparison of its growth in three different media (diluted seawater, seawater, and seawater +0.5M NaCl) revealed a faster growth in the hypersaline medium. In the hypersaline medium, the culture was homogeneous, in contrast to the aggretates formed in the lower-salt media. Enzymic analysis of the cells demonstrated selective sensitivity of soluble malate dehydrogenase to sodium ions, while chloride ions or nonionic solutes caused no inhibition. The membrane-associated enzyme ferredoxin-NADP reductase was only partially sensitive to sodium ions. The respiratory enzymes exhibited well-coupled activity, and faster respiration was observed with the preparation from the hypersaline culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182237
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