• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of aemPermissionsJournals.ASM.orgJournalAEM ArticleJournal InfoAuthorsReviewers
Appl Environ Microbiol. Feb 1990; 56(2): 488–494.
PMCID: PMC183366

Osmoregulation in Rhizobium meliloti: Production of Glutamic Acid in Response to Osmotic Stress

Abstract

Rhizobium meliloti, like many other bacteria, accumulates high levels of glutamic acid when osmotically stressed. The effect was found to be proportional to the osmolarity of the growth medium. NaCl, KCI, sucrose, and polyethylene glycol elicited this response. The intracellular levels of glutamate and K+ began to increase immediately when cells were shifted to high-osmolarity medium. Antibiotics that inhibit protein synthesis did not affect this increase in glutamate production. Cells growing in conventional media at any stage in the growth cycle could be suspended in medium causing osmotic stress and excess glutamate accumulated. The excess glutamate did not appear to be excreted, and the intracellular level eventually returned to normal when osmotically stressed cells were suspended in low-osmolarity medium. A glt mutant lacking glutamate synthase and auxotrophic for glutamate accumulated excess glutamate in response to osmotic stress. Addition of isoleucine, glutamine, proline, or arginine stimulated glutamate accumulation to wild-type levels when the mutant cells were suspended in minimal medium with NaCl to cause osmotic stress. In both wild-type and mutant cells, inhibitors of transaminase activity, including azaserine and aminooxyacetate, reduced glutamate levels. The results suggest that the excess glutamate made in response to osmotic stress is derived from degradation of amino acids and transamination of 2-ketoglutarate.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.2M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Boos W, Ehmann U, Bremer E, Middendorf A, Postma P. Trehalase of Escherichia coli. Mapping and cloning of its structural gene and identification of the enzyme as a periplasmic protein induced under high osmolarity growth conditions. J Biol Chem. 1987 Sep 25;262(27):13212–13218. [PubMed]
  • Brenchley JE. Effect of methionine sulfoximine and methionine sulfone on glutamate synthesis in Klebsiella aerogenes. J Bacteriol. 1973 May;114(2):666–673. [PMC free article] [PubMed]
  • Csonka LN. Physiological and genetic responses of bacteria to osmotic stress. Microbiol Rev. 1989 Mar;53(1):121–147. [PMC free article] [PubMed]
  • Dendinger SM, Patil LG, Brenchley JE. Salmonella typhimurium mutants with altered glutamate dehydrogenase and glutamate synthase activities. J Bacteriol. 1980 Jan;141(1):190–198. [PMC free article] [PubMed]
  • Ditta G, Stanfield S, Corbin D, Helinski DR. Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7347–7351. [PMC free article] [PubMed]
  • Giaever HM, Styrvold OB, Kaasen I, Strøm AR. Biochemical and genetic characterization of osmoregulatory trehalose synthesis in Escherichia coli. J Bacteriol. 1988 Jun;170(6):2841–2849. [PMC free article] [PubMed]
  • Gober JW, Kashket ER. K regulates bacteroid-associated functions of Bradyrhizobium. Proc Natl Acad Sci U S A. 1987 Jul;84(13):4650–4654. [PMC free article] [PubMed]
  • Hua SS, Tsai VY, Lichens GM, Noma AT. Accumulation of Amino Acids in Rhizobium sp. Strain WR1001 in Response to Sodium Chloride Salinity. Appl Environ Microbiol. 1982 Jul;44(1):135–140. [PMC free article] [PubMed]
  • Leirmo S, Harrison C, Cayley DS, Burgess RR, Record MT., Jr Replacement of potassium chloride by potassium glutamate dramatically enhances protein-DNA interactions in vitro. Biochemistry. 1987 Apr 21;26(8):2095–2101. [PubMed]
  • Le Rudulier D, Strom AR, Dandekar AM, Smith LT, Valentine RC. Molecular biology of osmoregulation. Science. 1984 Jun 8;224(4653):1064–1068. [PubMed]
  • LOWRY OH, ROSEBROUGH NJ, FARR AL, RANDALL RJ. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed]
  • Ludwig RA. Physiological roles of glutamine synthetases I and II in ammonium assimilation in Rhizobium sp. 32H1. J Bacteriol. 1980 Mar;141(3):1209–1216. [PMC free article] [PubMed]
  • Magasanik B. Genetic control of nitrogen assimilation in bacteria. Annu Rev Genet. 1982;16:135–168. [PubMed]
  • Measures JC. Role of amino acids in osmoregulation of non-halophilic bacteria. Nature. 1975 Oct 2;257(5525):398–400. [PubMed]
  • Miller KJ, Kennedy EP, Reinhold VN. Osmotic adaptation by gram-negative bacteria: possible role for periplasmic oligosaccharides. Science. 1986 Jan 3;231(4733):48–51. [PubMed]
  • Miller RE, Stadtman ER. Glutamate synthase from Escherichia coli. An iron-sulfide flavoprotein. J Biol Chem. 1972 Nov 25;247(22):7407–7419. [PubMed]
  • Osburne MS, Signer ER. Ammonium assimilation in Rhizobium meliloti. J Bacteriol. 1980 Sep;143(3):1234–1240. [PMC free article] [PubMed]
  • Perroud B, Le Rudulier D. Glycine betaine transport in Escherichia coli: osmotic modulation. J Bacteriol. 1985 Jan;161(1):393–401. [PMC free article] [PubMed]
  • Pocard JA, Bernard T, Smith LT, Le Rudulier D. Characterization of three choline transport activities in Rhizobium meliloti: modulation by choline and osmotic stress. J Bacteriol. 1989 Jan;171(1):531–537. [PMC free article] [PubMed]
  • Postma PW, Keizer HG, Koolwijk P. Transport of trehalose in Salmonella typhimurium. J Bacteriol. 1986 Dec;168(3):1107–1111. [PMC free article] [PubMed]
  • Richey B, Cayley DS, Mossing MC, Kolka C, Anderson CF, Farrar TC, Record MT., Jr Variability of the intracellular ionic environment of Escherichia coli. Differences between in vitro and in vivo effects of ion concentrations on protein-DNA interactions and gene expression. J Biol Chem. 1987 May 25;262(15):7157–7164. [PubMed]
  • Smith LT, Pocard JA, Bernard T, Le Rudulier D. Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti. J Bacteriol. 1988 Jul;170(7):3142–3149. [PMC free article] [PubMed]
  • Smith LT, Smith GM. An osmoregulated dipeptide in stressed Rhizobium meliloti. J Bacteriol. 1989 Sep;171(9):4714–4717. [PMC free article] [PubMed]
  • Snapp SS, Vance CP. Asparagine Biosynthesis in Alfalfa (Medicago sativa L.) Root Nodules. Plant Physiol. 1986 Oct;82(2):390–395. [PMC free article] [PubMed]
  • Styrvold OB, Falkenberg P, Landfald B, Eshoo MW, Bjørnsen T, Strøm AR. Selection, mapping, and characterization of osmoregulatory mutants of Escherichia coli blocked in the choline-glycine betaine pathway. J Bacteriol. 1986 Mar;165(3):856–863. [PMC free article] [PubMed]
  • Tempest DW, Meers JL, Brown CM. Influence of environment on the content and composition of microbial free amino acid pools. J Gen Microbiol. 1970 Dec;64(2):171–185. [PubMed]
  • Yancey PH, Clark ME, Hand SC, Bowlus RD, Somero GN. Living with water stress: evolution of osmolyte systems. Science. 1982 Sep 24;217(4566):1214–1222. [PubMed]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...