Synthese von Speicherstoffen aus Pyruvat durch Rhodospirillum rubrum

Bosshard-Heer, Elisabeth; Bachofen, Reinhard

doi:10.1007/bf00412065

Cited by 12 publications

(5 citation statements)

References 17 publications

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“…To our knowledge, this is the first report of poly-,B-hydroxybutyric acid synthesis in fermentative me-tabolism. The data suggest that an pyruvate clastic reaction may function dark growth, electrons being transferred drogenase as well as to the polymer-forming system (2,7,27).…”

Section: Figmentioning

confidence: 94%

Mutants of Rhodospirillum rubrum Obtained After Long-Term Anaerobic, Dark Growth

1971

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Rhodospirillum rubrum S, cells were grown for more than 100 generations under strict anaerobic, dark conditions in liquid medium with sodium pyruvate. During this time, growth became nonpigmented. When cells were streaked onto the surface of solid growth medium in anaerobic bottles and placed in the dark, a few light-red colonies developed, but the majority was nonpigmented. Mutants were obtained from colonies selected on the basis of pigmentation and bacteriochlorophyll a content. The growth, ultrastructure, and light reactivity of two mutants were examined. Mutant C synthesized bacteriochlorophyll a (7.2 itmoles per mg of protein), altered membrane structures, and chromatophores during dark growth. Examination of light-induced changes of the absorption spectrum of this mutant suggested that only an electron transport pathway, which included the low potential cytochrome-like pigment C428, could be detected. Mutant C grew anaerobically in the light, whereas mutant GI was light sensitive and produced only trace amounts of bacteriochlorophyll a (0.6 gmole per ml of protein). Poorly pigmented G1 cells contained unusual membrane structures. When dark-grown G1 colonies were placed in the light, deep-red colored papillae developed in the nonpigmented colonies. During anaerobic, dark growth with sodium pyruvate, both C and G1 synthesized poly-,3-hydroxybutyrate and produced acetate, carbon dioxide, and hydrogen gas. were collected by centrifugation and washed in distilled water. Bacteriochlorophyll a was extracted as pre-1348

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Section: Figmentioning

confidence: 94%

Mutants of Rhodospirillum rubrum Obtained After Long-Term Anaerobic, Dark Growth

1971

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“…1) and by the observation that cell extracts from anaerobic, dark-grown R. rubrum catalyzed the production of small amounts of C02, but not H2, from sodium pyruvate even during incubation with sodium hypophosphite (unpublished data). In addition to NAD(P)+ re- on October 6, 2020 by guest http://jb.asm.org/ Downloaded from duction, the pyruvate:ferredoxin oxidoreductase pathway could operate, as in light-brown R. rubrum (2), and help explain the accumulation of poly-,6-hydroxybutyrate in cells during anaerobic dark development (34,35).…”

Section: Fig 5 Production Of ['4cmentioning

confidence: 99%

Fermentative metabolism of pyruvate by Rhodospirillum rubrum after anaerobic growth in darkness

Gorrell¹,

Uffen²

1977

J Bacteriol

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Rhodospirillum rubrum grew anaerobically in darkness and fermented sodium pyruvate by a pyruvate formate-lyase reaction. During 30 min of anaerobic dark or light incubation with sodium pyruvate, crude extracts from fermentatively grown cells produced about 6 yimol of acetylphosphate and formate per mg of protein in reactions performed at pH 8.3. Cell extracts also catalyzed the exchange of sodium [14C]formate into sodium pyruvate at an apparent pH optimum of 7.3 to 7.5, but only about 2.5 ,zmol of acetylphosphate was produced at this lower pH value. R. rubrum may also form pyruvate:ferredoxin oxidoreductase activity, as evidenced by low bicarbonate exchange activity. However, its participation in pyruvate metabolism in anaerobic dark-grown cells was not understood. During anaerobic, dark growth with pyruvate, formate was an intermediate in H2 and C02 gas evolution. In contrast with H2 production by a light-dependent H2-nitrogenase system in photosynthetically grown cells, H2 formation in fermenting R. rubrum occurred through a carbon monoxidesensitive formic hydrogenlyase reaction not influenced by light.

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“…Cells produced less hydrogen than CO2 during pyruvate fermentation ( Table 5). The lowered amount of H2 evolved could be expected to arise, in part, during synthesis of poly-Bhydroxybutyric acid (6,12) and reduction of pyridine nucleotides during synthesis of cell material. The ratio of oxidized versus reduced J. BACrERIOL.…”

Section: Resultsmentioning

confidence: 99%

“…R. rubrum may not be unique in possessing two energy-yielding pathways for pyruvate degradation during fermentative growth; a similar situation was reported for Sarcina maxima (27) and Micrococcus lactilyticus (28,47). Moreover, from numerous investigations on carbon metabolism in light-grown R. rubrum (3,6,(15)(16)(17), it appeared that both pathways might function in different aspects of photosynthetic cell growth. The process whereby one or both pathways became the primary energy evolving system(s) during anaerobic, dark growth was the intriguing question.…”

Section: Resultsmentioning

confidence: 99%

Growth Properties of Rhodospirillum rubrum Mutants and Fermentation of Pyruvate in Anaerobic, Dark Conditions

Uffen

1973

J Bacteriol

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Mutant C and G1 were obtained earlier from Rhodospirillum rubrum S 1 during growth in the dark under strict anaerobic conditions in medium containing sodium pyruvate. Mutant C and mutant G1 grew in the dark with generation times of 5.8 h and 4.6 h, respectively. Mutant C cells grew equally well when switched between anaerobic (dark or light) or aerobic, dark conditions. Mutant G1 cells grew only in the dark (anaerobic or aerobic conditions), but a fraction of cells in anaerobic, dark cultures grew when placed in light. This number increased about 3,000-fold when G1 cells were incubated aerobically in the dark. During anaerobic, dark growth, C and G1 organisms incorporated similar amounts of [2- 14 C ]sodium pyruvate. About 34% of the incorporated radioactivity was found in lipid fractions from C cells that developed chromatophores during dark growth. Similar results were obtained using G1 cells, which formed only trace amounts of photosynthetic structures. Both mutants fermented sodium pyruvate and produced acetate, formate, carbon dioxide, and hydrogen gas. Molar growth yield coefficients indicated that the cells obtained about 1 mol of adenosine triphosphate per mol of sodium pyruvate fermented. Results suggested that pyruvate fermentation during dark growth occurred via a pyruvate formate-lyase or the pyruvate ferredoxin-oxidoreductase pathway, or both.

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Synthese von Speicherstoffen aus Pyruvat durch Rhodospirillum rubrum

Cited by 12 publications

References 17 publications

Mutants of Rhodospirillum rubrum Obtained After Long-Term Anaerobic, Dark Growth

Mutants of Rhodospirillum rubrum Obtained After Long-Term Anaerobic, Dark Growth

Fermentative metabolism of pyruvate by Rhodospirillum rubrum after anaerobic growth in darkness

Growth Properties of Rhodospirillum rubrum Mutants and Fermentation of Pyruvate in Anaerobic, Dark Conditions

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