Increase in Osmotolerance of Rhizobium fredii Soybean Isolate BD32 by the proB proA Operon of Escherichia coli

Neumivakin, L. V.; Solovjev, V. P.; Sokhansanj, A.; Тильба, В А; Moseiko, N. A.; Shachbasian, R. V.; Пирузян, Е. С.

doi:10.1006/bbrc.1995.2842

Cited by 2 publications

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“…However, we believe that preventing the catabolism of glycine betaine might not be the most judicious approach because betaines, such as stachydrine (N,N-dimethylproline), trigonelline, and possibly glycine betaine itself, also function as valuable nutritional mediators and nod gene inducers during the symbiosis between alfalfa and S. meliloti (12)(13)(14). Alternatively, the osmotolerance of Rhizobium species could be increased through genetic engineering of metabolic pathways encoding the synthesis of new osmolytes which do not play a crucial role in nutrition and/or in symbiosis in these species (22).…”

Section: Discussionmentioning

confidence: 99%

Transient Accumulation of Glycine Betaine and Dynamics of Endogenous Osmolytes in Salt-Stressed Cultures of Sinorhizobium meliloti

Talibart

Jebbar

Gouffi

et al. 1997

Appl Environ Microbiol

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The fate of exogenously supplied glycine betaine and the dynamics of endogenous osmolytes were investigated throughout the growth cycle of salt-stressed cultures of strains of Sinorhizobium meliloti which differ in their ability to use glycine betaine as a growth substrate, but not as an osmoprotectant. We present (sup13)C nuclear magnetic resonance spectral and radiotracer evidence which demonstrates that glycine betaine is only transiently accumulated as a cytoplasmic osmolyte in young cultures of wild-type strains 102F34 and RCR2011. Specifically, these strains accumulate glycine betaine as a preferred osmolyte which virtually prevents the accumulation of endogenous osmolytes during the lag and early exponential phases of growth. Then, betaine levels in stressed cells decrease abruptly during the second half of the exponential phase. At this stage, the levels of glutamate and the dipeptide N-acetylglutaminylglutamine amide increase sharply so that the two endogenous solutes supplant glycine betaine in the ageing culture, in which it becomes a minor osmolyte because it is progressively catabolized. Ultimately, glycine betaine disappears when stressed cells reach the stationary phase. At this stage, wild-type strains of S. meliloti also accumulate the disaccharide trehalose as a third major endogenous osmolyte. By contrast, glycine betaine is always the dominant osmolyte and strongly suppresses the buildup of endogenous osmolytes at all stages of the growth cycle of a mutant strain, S. meliloti GMI766, which does not catabolize this exogenous osmoprotectant under any growth conditions.

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Section: Discussionmentioning

confidence: 99%

Transient Accumulation of Glycine Betaine and Dynamics of Endogenous Osmolytes in Salt-Stressed Cultures of Sinorhizobium meliloti

Talibart

Jebbar

Gouffi

et al. 1997

Appl Environ Microbiol

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Insights into Pseudomonas putida KT2440 response to phenol‐induced stress by quantitative proteomics

Santos¹,

2004

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To gain insight into the global mechanism underlying phenol toxicity and tolerance in bacteria, we have generated a two-dimensional protein reference map and used it to identify variations in protein expression levels in Pseudomonas putida KT2440 following exposure to sub-lethal inhibitory concentrations of this solvent. Inspection of the two-dimensional gel electrophoresis gels revealed that 1 h following sudden cell exposure to two different concentrations of phenol, leading to the inhibition of exponential growth (600 mg/L) or to growth arrest for, at least, 4 h before inhibited growth resumption (800 mg/L), the amount of 68 proteins was increased while the amount of 13 proteins was reduced. The up-regulated proteins include proteins involved in the: (i) oxidative stress response (AhpC, SodB,Tpx and Dsb); (ii) general stress reponse (UspA, HtpG, GrpE and Tig); (iii) energetic metabolism (AcnB, AtpH, Fpr, AceA, NuoE, and MmsA-1); (iv) fatty acid biosynthesis (FabB, AccC-1 and FabBx1); (v) inhibition of cell division (MinD); (vi) cell envelope biosynthesis (LpxC, VacJ, and MurA); (vii) transcription regulation (OmpR and Fur); and (viii) transport of small molecules (TolC, BraC, AotJ, AapJ, FbpA and OprQ). Among the down-regulated proteins are those involved in nucleotide biosynthesis (PurM, PurL, PyrH and Dcd) and cell motility (FliC). The information emerging from this genome expression profiling and the detailed investigation of the biological role of candidate genes, as targets of phenol toxicity or as determinants of phenol resistance in P. putida KT2440, will allow more rationale strategies for developing bacteria with greater solvent tolerance with impact in bioremediation and whole-cell biotransformations in media with organic solvents.

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Increase in Osmotolerance of Rhizobium fredii Soybean Isolate BD32 by the proB proA Operon of Escherichia coli

Cited by 2 publications

References 0 publications

Transient Accumulation of Glycine Betaine and Dynamics of Endogenous Osmolytes in Salt-Stressed Cultures of Sinorhizobium meliloti

Transient Accumulation of Glycine Betaine and Dynamics of Endogenous Osmolytes in Salt-Stressed Cultures of Sinorhizobium meliloti

Insights into Pseudomonas putida KT2440 response to phenol‐induced stress by quantitative proteomics

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