ISSN:
1432-072X
Keywords:
Desulfovibrio
;
Chemolithotrophic growth
;
Acetate and CO2 assimilation
;
Amino acid synthesis
;
(R)-Citrate sythase
;
Pentose phosphates synthesis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Desulfovibrio vulgaris (Marburg) was grown on hydrogen plus sulfate as sole energy source and acetate plus CO2 as the sole carbon sources. The incorporation of U-14C acetate into alanine, aspartate, glutamate, and ribose was studied. The labelling data show that alanine is synthesized from one acetate (C-2 + C-3) and one CO2 (C-1), aspartate from one acetate (C-2 + C-3) and two CO2 (C-1 + C-4), glutamate from two acetate (C-1−C-4) and one CO2 (C-5), and ribose from 1.8 acetate and 1.4 CO2. These findings indicate that in Desulfovibrio vulgaris (Marburg) pyruvate is formed via reductive carboxylation of acetyl-CoA, oxaloacetate via carboxylation of pyruvate or phosphoenol pyruvate, and α-ketoglutarate from oxaloacetate plus acetyl-CoA via citrate and isocitrate. Since C-5 of glutamate is derived from CO2, citrate must have been formed via a (R)-citrate synthase rather than a(S)-citrate synthase. The synthesis of ribose from 1.8 mol of acetate and 1.4 mol of CO2 excludes the operation of the Calvin cycle in this chemolithotrophically growing bacterium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00406665
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