Article Abstract:
Amino acid uptake by the general amino acid permease (Aap) of Rhizobium leguminosarum strain 3841 was greatly reduced by the presence of aspartate in the growth medium when glucose was the carbon source. This was due to the prevention of uptake and not by transcriptional repression. However, the Ntr-regulated gene glnII was repressed by aspartate. The negative regulatory effect on both the Aap and glnII was prevented by mutation of any component of the dicarboxylate transport system or by the inclusion of a C4-dicarboxylate in the growth medium, including the non-metabolizable analogue 2-methylsuccinate.
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Article Abstract:
A comparative analysis was made between the MCP-independent systems in enteric bacteria and the chemotactic systems in Rhodobacter sphaeroides. In this study, chemotaxis was mediated through transport and phosphorylation via phosphoenolpyruvate-dependent phosphotransferase system or through chemotaxis pathway. Results show that chemotactic signal in R. sphaeroides will most likely be created through activities of the electron-transport chain or metabolic intermediates.
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Article Abstract:
The regulation of the uptake activity of the amino acid permease (Aap) in Rhizobium leguminosarum by the TCA cycle via the synthesis of the amino acids was demonstrated. The 2-oxoglutarate dehydrogenase was found to be the main enzyme. Results reveal that the TCA cycle in R. leguminosorum is regulated by the amino acid excretion and polyhydroxybutyrate biosynthesis which act as overflow pathways for excess carbon and reductant.
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