Increased activity of respiratory enzymes from photosynthetically grown Rhodopseudomonas capsulata in response to small amounts of oxygen

Distribution and Capacity for Utilization of Lower Fatty Acids of Phototrophic Purple Nonsulfur Bacteria in Wastewater Environments

“…The differences between the Rhodopseudomonas and Rhodobacter species in affinity for acetate may be partly derived from the difference in the metabolic pathway for acetate, e.g., the glyoxylate cycle. The key enzymes of this pathway, isocitrate lyase and malate synthase, could be detected in Rhodopseudomonas palustris grown on acetate but were not detectable in Rhodobacter sphaeroides 1,6,31) .…”

Deodorization of swine sewage by addition of a phototrophic bacterium,Rhodopseudomonas capsulata

“…Accumulated data suggest that the growth of R. capsulata in the photosynthetic activated-sludge system depends on the concentration of organic carbon sources in wastewater, particularly short chain fatty acids (Hiraishi and Kitamura 1984). It was also reported that acetate, propionate, butyrate, and some higher homologues were good substrates as carbon sources for R. capsulata under anaerobic and aerobic conditions (Cox et al 1983). Thus, it is suggested that the addition of R. capsulata to swine sewage may result in the utilization of these volatile short chain fatty acids as carbon sources, leading to the reduction of the amounts of VFAs.…”

Cloning, sequencing, and oxygen regulation of the Rhodobacter capsulatus alpha-ketoglutarate dehydrogenase operon

“…It has been reported that the activities of KGD and other enzymes involved in respiration, although present, are lower in cultures of R. capsulatus grown under anaerobic photosynthetic growth conditions than under aerobic conditions (4,12). These changes in KGD and other respiratory enzyme activities suggest that although the CAC functions under photosynthetic growth conditions, its activity is reduced because it is required only for the generation of biosynthetic precursors.…”

“…During aerobic respiratory growth, R. capsulatus uses the citric acid cycle (CAC) to produce reducing equivalents for ATP synthesis by oxidative phosphorylation (4,12). When the oxygen tension in the growth environment drops below a critical concentration, cells of R. capsulatus respond by modification of metabolic pathways and synthesis of differentiated membrane structures for photosynthetic energy transduction (14).…”

“…These three proteins form a large complex with a molecular weight in excess of 10 6 and a normalized protein stoichiometry of 1E1o:2E2o:1E3 (for summaries of ␣-keto acid dehydrogenase complexes, see reference 29). Oxygen regulation of KGD enzymatic activity appears to be important for the modulation of CAC activity in organisms (such as R. capsulatus and Escherichia coli) that are capable of aerobic and anaerobic growth, and the KGD activity generally reflects overall CAC activity and respiration (4,12,35,38). The E. coli genes sucA, sucB, and lpd (which encode the E1o, E2o, and E3 proteins, respectively) have been cloned and sequenced, and their structures, as well as aspects of their regulation of expression, have been elucidated in a series of elegant publications by Guest and colleagues (25).…”