Abstract
The pathway by which glutamate is degraded as a carbon source has not previously been elucidated, but enzymatic analysis of Rhizobium meliloti CMF1 indicated that both glutamate dehydrogenase (GDH) and gamma-aminobutyrate (GABA) bypass activities were present in free living cells. However, when similar studies were performed on R. meliloti CMF1 bacteroids, isolated from alfalfa nodules, only GABA bypass activities were detectable. Both GDH and GABA bypass activities were influenced by the carbon source provided, with maximum activities being detected when glutamate was present as sole carbon and nitrogen source. Addition of a second carbon source, such as succinate, to the growth medium did not influence GDH activity but substantially decreased levels of the first enzyme of the GABA bypass, glutamate decarboxylase (GDC). Cyclic adenosine 3′5′-monophosphate (cAMP) failed to increase GDC activities in R. meliloti CMF1 cells grown in the presence of an additional carbon source. It is proposed that the GABA bypass is a major mechanism of glutamate carbon degradation in R. meliloti CMF1, a system whose enzymatic activities are influenced by the nature of the carbon source present in the growth environment.
Similar content being viewed by others
References
Bolton E, Higgisson B, Harrington A, O'Gara F (1986) Dicarboxylic acid transport in Rhizobium meliloti; isolation of mutants and cloning of dicarboxylic acid transport genes. Arch Microbiol 144: 142–146
Cooper AJL (1985) Glutamate-aspartate transaminase and glutamate alanine transaminase. In: Meister A (ed) Methods in enzymology, vol. 113. Academic Press, Orlando, Florida, pp 66–71
Donnelly I, Cooper RA (1981) Succinic semialdehyde dehydrogenases of Escherichia coli. Their role in the degradation of p-hydroxy-phenylacetate and gamma-aminobutyrate. J Biochem 13: 555–561
Dover S, Halpern YS (1972) Control of the pathway of gamma-aminobutyrate breakdown in Escherichia coli K-12. J Bacteriol 109: 165–170
Finan TM, Wood JM, Jordan DC (1983) Symbiotic properties of C4 dicarboxylic acid transport mutants of Rhizobium leguminosarum. J Bacteriol 154: 1403–1413
Fitzmaurice AM, O'Gara F (1988) Involvement of glutamate as a carbon source in supporting nitrogen fixation activity in R. meliloti. In: Bothe H, Bruijn FJ de, Newton WE (eds) Proceedings of 7th International Congress on Nitrogen Fixation. Fischer, Stuttgart New York, p 558
Freney JR, Gibson AH (1975) Accumulation of 4-aminobutyrate in Trifolium subterraneum root nodules: effect of Rhizobium trifolii on aminotransferase activity. Aust J Plant Physiol 2: 663–668
Halpern YS (1962) Induction and repression of glutamic acid decarboxylase in Escherichia coli. Biochim Biophys Acta 61: 953–962
Jin HN, Glenn AR, Dilworth MJ (1988) Metabolism of 4-aminobutyrate (GABA) by cowpea Rhizobium MNF2030. In: Bothe H, Bruijn FJ de, Newton WE (eds) Proceedings of 7th International Congress on Nitrogen Fixation. Fischer, Stuttgart New York, p 560
Kahn ML, Kraus J, Somerville JE (1985) A model of nutrient exchange in the Rhizobium-legume symbiosis. In: Evans HJ, Bottomley PJ, Newton WE (eds) Nitrogen Fixation Research Progress. Nijhoff, Dordrecht, pp 193–199
Kahn ML, Kraus J, Shatters RG (1988) Bacterial catabolism of nitrogen containing compounds in symbiotic nitrogen fixation. In: O'Gara F, Manian SS, Drevon JJ (eds) Physiological limitations and the genetic improvement of symbiotic nitrogen fixation. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp 21–27
Kohl DH, Schubert KR, Carter MB, Hagedorn CH, Shearer G (1988) Proline metabolism in N2-fixing nodules: energy transfer and regulation of purine synthesis. Proc Natl Acad Sci USA 85: 2036–2040
Kouchi H, Fukai K (1988) Absorption and utilisation of aspartate and glutamate by soybean nodule bacteroids. In: Bothe H, Bruijn FJ de, Newton WE (eds) Proceedings of 7th International Congress on Nitrogen Fixation. Fischer, Stuttgart New York, p 561
Lowry OH, Rosenbrugh NJ, Farr AL, Randall RJ (1951) Protein measurement with the folin phenol reagent. J Biol Chem 193: 265–275
Manian SS, O'Gara F (1982) Derepression of bisphosphate carboxylase activity in Rhizobium meliloti. FEMS Microbiol Lett 14: 95–99
Manian SS, Gumbleton R, O'Gara F (1982) The role of formate metabolism in nitrogen fixation in Rhizobium spp. Arch Microbiol 133: 312–317
O'Gara F, Shanmugam KT (1976) Control of symbiotic nitrogen fixation in Rhizobia. Regulation of NH +4 assimilation. Biochim Biophys Acta 437: 313–321
Pain AN (1979) Symbiotic properties of antibiotic resistant and auxotrophic mutants of Rhizobium leguminosarum J Appl Bacteriol 47: 53–64
Ronson CW, Lyttleton P, Robertson JG (1981) C4-dicarboxylate transport mutants of Rhizobium trifolii form ineffective nodules on Trifolium repens. Proc Natl Acad Sci USA 78: 4284–4288
Saier MH, Jenkins WT (1967) Alanine aminotransferase (1) purification and properties. J Biol Chem 242: 91–101
Salminen SO, Streeter JG (1987) Involvement of glutamate in the respiratory metabolism of Bradyrhizobium japonicum bacteroids. J Bacteriol 169: 495–499
Stowers MD (1985) Carbon metabolism in Rhizobium species. Ann Rev Microbiol 39: 89–108
Streeter JG (1987) Carbohydrate, organic acid and amino acid composition of bacteroids and cytosol from soybean nodules. Plant Physiol 85: 768–773
Streeter JG, Salminen SO (1988) Carbon metabolism and the exchange of metabolites between symbionts in legume nodules. In: O'Gara F, Manian SS, Drevon JJ (eds) Physiological Limitations and the Genetic Improvement of Symbiotic Nitrogen Fixation. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp 11–20
Tyler B (1978) Regulation of the assimilation of nitrogen compounds. Ann Rev Biochem 47: 1127–1162
Udvardi MK, Day DA (1988) Metabolite transport across the peribacteroid membrane from soybean root nodules. In: Bothe H, Bruijn FJ de, Newton WE (eds) Proceedings of 7th International Congress on Nitrogen Fixation. Fischer, Stuttgart New York, p 534
Wang YP, Birkenhead K, Boesten B, Manian SS, O'Gara F (1989) Genetic analysis and regulation of the Rhizobium meliloti genes controlling C4-dicarboxylic acid transport. Gene 85: 135–144
Yonaha K, Toyama S (1980) Gamma-aminobutyrate: α-ketoglutarate aminotransferase from Pseudomonas sp. F-126: purification, crystallization and enzymological properties. Arch Biochim Biophys 200: 156–164
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Fitzmaurice, A.M., O'Gara, F. Glutamate catabolism in Rhizobium meliloti . Arch. Microbiol. 155, 422–427 (1991). https://doi.org/10.1007/BF00244956
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00244956