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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 96 (1974), S. 161-174 
    ISSN: 1432-072X
    Keywords: Membrane Proteins ; Reaction Center ; Intracytoplasmic Membrane ; Rhodopseudomonas capsulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intracytoplasmic membranes of wild type strain 37 b 4 and mutant strains A1a car-bchl-, A1a car-bchl+ ofRhodopseudomonas capsulata were isolated. The membrane proteins were solubilized and separated by polyacrylamide gel electrophoresis (methods of Takayamaet al., 1964; Weber and Osborn, 1969). The band patterns were compared with each other. From the strain A1a car-bchl+ reaction center particles were isolated by treatment of membrane with Triton X-100 followed by sucrose density gradient centrifugation. The reaction center particles were found to be enriched in reaction center bacteriochlorophyll. This pigment shows a reversible bleaching at 855 nm and a blue shift at 798 nm. The light harvesting bacteriochlorophyll portion of this fraction was 14–22% of the total bacteriochlorophyll content. The three main proteins of the reaction center particles amount to about 80% of the total protein of the particles. The molecular weights of the main proteins were estimated to be 32000, 27500 and 22500 daltons.
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  • 2
    ISSN: 1432-072X
    Keywords: Continuous Culture ; Rhodopseudomonas capsulata ; Bacteriochlorophyll ; Protein ; Poly-β-Hydroxybutyrate ; Nitrogen Limitation ; Oxygen Control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A continuous culture apparatus is described, which allows cultivation of photosynthetic bacteria anaerobically in the light and semiaerobically in the dark at constant oxygen tensions. The growth-parameters 1. substrate concentration at half maximum growth rate (K s) and 2. yield (Y) forRhodopseudomonas capsulata are calculated. An automatic control system of the oxygen partial pressure in the culture medium is elaborated. It is shown, that the discontinuous regulation with a control unit in connection with two magnetic valves, which give short pulses of either oxygen-free gas or gas mixed with oxygen, is an economic, practicable and reliable method. The yield coefficientY during growth limited by ammonium sulfate is variable due to the synthesis of nitrogen independent metabolites, such as poly-β-hydroxybutyrate. The storage of poly-β-hydroxybutyrate in continuous culture is a function of both the actual concentration of ammonia and of theC/N ratio. At very low growth rates (1/6 µ m ) the poly-β-hydroxybutyrate content increases amounting to 33% of the dry weight. In semiaerobically dark grown cells (pO2: 5 mm Hg) the protein and bacteriochlorophyll content increased definitely on dry weight basis with increasing growth rates. In contrast, in anaerobic light cultures only a small increase of the bacteriochlorophyll level but no change of the protein content per dry weight of cells was observed at increasing growth rates.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 145 (1986), S. 378-385 
    ISSN: 1432-072X
    Keywords: Transposon Tn5 ; Cytochrome oxidase ; Cytochrome c ; Respiratory mutants ; Rhodopseudomonas capsulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The facultative photosynthetic bacterium Rhodopseudomonas capsulata was mutagenized by transfer of the plasmid pSUP201::Tn5 from Escherichia coli to R. capsulata. Mutants defective in cytochrome oxidase and other respiratory functions were selected by replica plating, NADI-reaction and immunological methods. Among 20,000 mutants no clone was detected, which lacks the 65,000-protein of the cytochrome oxidase, but many mutants have been isolated which were cytochrome oxidase deficient (or inactive). Other mutants excrete heme and cytochrome c′ into the medium and lack cytochrome c 2.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 139 (1984), S. 319-325 
    ISSN: 1432-072X
    Keywords: Gene bank ; Plasmids pRK290 ; pRK2013 ; Rhodopseudomonas capsulata ; Reconstitution ; Phototroph negative mutants ; Absorption spectra ; Light harvesting complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene bank of the phototrophic bacterium Rhodopseudomonas capsulata was constructed using the binary plasmid system pRK290/pRK2013. Fragments of about 20 kb of chromosomal DNA of R. capsulata strain 37b4 were inserted into the cloning vector pRK290. The hybrid plasmids of the gene bank, maintained in Escherichia coli HB101 were transferred by conjugation to R. capsulata strains defective in the photosynthetic apparatus with frequencies of 5×10-4 to 5×10-2. Phototrophically growing transconjugants occurred with frequencies of 5×10-7 to 5×10-6. Recombination between the hybrid plasmids and the R. capsulata chromosome was shown. The hybrid plasmid pRCF1002, carrying a 25 kb insert of R. capsulata wild type DNA, was isolated from one E. coli clone of the gene bank. It reconstituted some bacteriochlorophyll- and photosynthetic negative mutants to phototrophic growth.
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  • 5
    ISSN: 1432-072X
    Keywords: Absorption spectra ; Fluorescence emission spectra ; Carotenoid band shift ; Excition transfer ; Light-harvesting complexes ; Rhodopseudomonas capsulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intracytoplasmic membranes of the mutant strain NK3 of Rhodopseudomonas capsulata lacking the lightharvesting complex B800-850 were fused with proteoliposomes containing the B800-850 complex. Fluorescence emission spectroscopy at 77K showed that after fusion the fluorescence of the B850 bacteriochlorophyll disappeared nearly completely and the B870 fluorescence became prominent. This result and control experiments with proteoliposome-chromatophore mixture and with chromatophore and solubilized B800-850 complexes, respectively, indicate that in fused membranes a reorientation of membrane particles took place and excitons migrated from B850 to B870 bacteriochlorophyll. In fused proteoliposome-chromatophore vesicles a light-induced carotenoid band shift was observed, reflecting the building of an electrical membrane potential due to chargeseparation. Carotenoid band shift was not observed in separated proteoliposomes and NK3 chromatophores. It is concluded that by membrane fusion and lateral diffusion of membrane particles reaction center-light-harvesting B870 complexes came in functional contact with B800-850 antenna complexes.
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  • 6
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas capsulata ; Pigment-protein complexes ; Bacteriochlorophyll synthesis ; Levulinic acid ; α,α′-dipyridyl ; δ-aminolevulinic acid ; Regulation of complex formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The synthesis of bacteriochlorophyll (Bchl) was inhibited in wild type strain of Rhodopseudomonas capsulata by levulinic acid (LA), δ-aminolevulinic acid of α,α′-dipyridyl. The transcription of genes for pigment-binding proteins, the synthesis and incorporation of these proteins into the membrane and the assembly of photosynthetic complexes were studied. Inhibition of Bchl synthesis did not impair formation of mRNA for pigment-binding polypeptides, but inhibited the synthesis of these proteins as well as stable incorporation into the membrane. The results let suggest, that Bchl is necessary for the stabilization of pigment-binding proteins in the membrane, and that intermediates of Bchl-synthesis affect the synthesis of these proteins. The same experiments were carried out with mutant strains blocked in Bchl synthesis. All Bchl-less mutant strains investigated here, showed transcription of photosynthetic genes at a rate which was independent of oxygen tension. The synthesis of polypeptides of reaction center, B870 and B800-850 complexes were differently affected by blocks in Bchl-synthesis. LA inhibited the synthesis of pigment-binding proteins in mutant strains similarly as in wild-type strain.
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  • 7
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas capsulata ; Photosynthetic apparatus ; Continuous culture ; Differentiation ; Influence of ammonium ; Oxygen tension ; Light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhodopseudomonas capsulata was grown either phototropically in the light or chemotrophically in the dark at oxygen tensions of 5 mm and 3 mm Hg in ammonium-limited continuous culture. During growth limitation bacteriochlorophyll content of cells and membranes varied dependent on growth rate drastically in chemotrophic cultures. Concomittantly, the ratio of membrane protein to total protein varied in the range of 30–41%. This dependence of membrane differentiation on growth rate was less evident in phototrophically grown cells. The incorporation of the bulk of bacteriochlorophyll was shown to be quantitatively correlated to the incorporation of 1–3 low molecular weight proteins with molecular weights in the range of 14 to less than 10 k daltons. Supported by similar findings of other authors it is proposed, that these proteins are to be attributed to the species of antenna bacteriochlorophyll and represent components of the photosynthetic apparatus. With decreasing growth rates the size of the photosynthetic unit with respect to the population of bacteriochlorophyll-and protein molecules was reduced subsequent to a reduction in the rate of incorporation of antenna-bacteriochlorophyll and the low molecular weight proteins, the reaction-center bacteriochlorophyll content of the membranes remaining constant. A parallel decrease in potential phosphorylating capacity was observed. It is concluded, that under these conditions, primary photochemical reactions in the reaction center were not the rate-limiting step in photophosphorylation. The interaction of growth limitation by an anabolic precursor (NH 4 + ) and control of membrane differentiation by light intensity or oxygen tension is discussed.
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  • 8
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas capsulata ; Membrane differentiation ; Photophosphorylation ; Succinate dehydrogenase ; NADH dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By means of sucrose density centrifugation three membrane fractions, named “light, medium and heavy” have been isolated from cells of Rhodopseudomonas capsulata strain 37b4, adapting from chemotrophic to phototrophic growth conditions. Succinate dehydrogenase activity of aerobically grown cells was mainly confined to the heavy (chromatophore) fraction. Upon changing to phototrophic conditions the activity of the succinate dehydrogenase increased in the medium and light fraction. All fractions contain bacteriochlorophyll. NADH dehydrogenase of chemotrophically grown cells was enriched in the light and medium fraction but is increased in the heavy fraction under phototrophic growth conditions. The capacity of photophosphorylation is high in the light and heavy fraction. The results indicate a differentially incorporation of functional subunits into specific parts of the membrane system during membrane differentiation.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 128 (1981), S. 376-383 
    ISSN: 1432-072X
    Keywords: Bacteriochlorophyll a ; Associated polypeptides ; Rhodopseudomonas capsulata ; Membrane differentiation ; Photosynthetic apparatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Early stages in the formation of membranes and photosynthetic units were studied under growth-limiting phototrophic and chemotrophic conditions in cells of Rhodopseudomonas capsulata. The incorporation of polypeptides, forming bacteriochlorophyll-carotinoid-protein complexes in the membrane, was followed by use of pulse-labeling and immunoprecipitation techniques. The newly synthesized polypeptides were inserted into two distinct membrane fractions at both different rates and proportions. The two membrane fractions differed in sedimentation behavior, absorption spectra and activities of the respiratory chain. The individual pigment-associated proteins did not exhibit precursor-product relationship between the two membrane fractions. The data suggest that newly synthesized polypeptides were integrated both into cytoplasmic and pre-existing intracytoplasmic membranes, where the proteins and pigments were assembled to form reaction centers and light-harvesting pigment-protein complexes.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 128 (1981), S. 390-393 
    ISSN: 1432-072X
    Keywords: Conjugational transfer ; R plasmids ; Rhodopseudomonas capsulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plasmids RP1, R68.45 and RP4::Mu cts 61 were transferred into Rhodopseudomonas capsulata from Escherichia coli. The frequency of intraspecies transfer of these plasmids in R. capsulata was 10-4–10-5 per donor. The plasmids also mobilized chromosomal genes at a low frequency. Phototrophic recombinants from matings between recipient strains defective in the photosynthetic-apparatus and wild type donors were obtained at a frequency of 10-7–10-8 per donor.
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