Abstract

We propose to perform a genetic and biochemical analysis of the mechanisms of osmotic regulation in the bacterium Salmonella typhimurium. The project is based on the observations that exogenous proline is stimulatory to S. typhimurium during osmotic stress, and that osmotic stress enhances the activity of two proline permeases, the ProP and the ProU systems. We shall investigate the mechanism of osmoregulatin in S. typhimurium by these specific aims: 1) we shall determine the effect of osmotic stress on the kinetic parameters of the ProP system, 2) we shall determine the effect of mutations in various proline transport systems on the intracellular proline levels, 3) we shall isolate pleiotropic osmoregulatory mutations that alter the expression of the proU gene and other genes subject to osmotic regulation and 4) we shall isolate, clone, and sequence mutations in the promoter region of the proU gene. The results obtained in the study of osmoregulation in bacteria are of value not only from the standpoint of basic science, but also because they have potential applications to the understanding of osmoregulation in plants and the genetic engineering of plants with increased tolerance of osmotic stress.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031944-06
Application #
3280381
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1983-09-27
Project End
1990-08-31
Budget Start
1988-09-01
Budget End
1990-08-31
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost

  Institution

Name
Purdue University
Department
Type
Schools of Arts and Sciences
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907

  Publications

Frymier, J S; Reed, T D; Fletcher, S A et al. (1997) Characterization of transcriptional regulation of the kdp operon of Salmonella typhimurium. J Bacteriol 179:3061-3
Zhang, X; Fletcher, S A; Csonka, L N (1996) Site-directed mutational analysis of the osmotically regulated proU promoter of Salmonella typhimurium. J Bacteriol 178:3377-9
Gutierrez, J A; Csonka, L N (1995) Isolation and characterization of adenylate kinase (adk) mutations in Salmonella typhimurium which block the ability of glycine betaine to function as an osmoprotectant. J Bacteriol 177:390-400
Fletcher, S A; Csonka, L N (1995) Fine-structure deletion analysis of the transcriptional silencer of the proU operon of Salmonella typhimurium. J Bacteriol 177:4508-13
Csonka, L N; Ikeda, T P; Fletcher, S A et al. (1994) The accumulation of glutamate is necessary for optimal growth of Salmonella typhimurium in media of high osmolality but not induction of the proU operon. J Bacteriol 176:6324-33
Overdier, D G; Csonka, L N (1992) A transcriptional silencer downstream of the promoter in the osmotically controlled proU operon of Salmonella typhimurium. Proc Natl Acad Sci U S A 89:3140-4
Csonka, L N; Hanson, A D (1991) Prokaryotic osmoregulation: genetics and physiology. Annu Rev Microbiol 45:569-606
Csonka, L N (1989) Physiological and genetic responses of bacteria to osmotic stress. Microbiol Rev 53:121-47
Overdier, D G; Olson, E R; Erickson, B D et al. (1989) Nucleotide sequence of the transcriptional control region of the osmotically regulated proU operon of Salmonella typhimurium and identification of the 5' endpoint of the proU mRNA. J Bacteriol 171:4694-706
Csonka, L N (1988) Regulation of cytoplasmic proline levels in Salmonella typhimurium: effect of osmotic stress on synthesis, degradation, and cellular retention of proline. J Bacteriol 170:2374-8

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