Salt tolerance in Rhizobium: A possible role for betaines

Rudulier, Daniel Le

doi:10.1016/0378-1097(86)90062-5

Cited by 30 publications

(18 citation statements)

References 19 publications

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“…It has no net charge, does not inhibit cytosolic enzymes, and even appears to protect them against salt damage [82,97]. This compound confers osmotolerance to a wide variety of organisms, including prokaryotes [reviewed in 82,87,91,92,[98][99][100][101]. In E. coli low-level osmotic stress results in increased K ÷ uptake by its two uptake transport systems, Kdp and Trk; the Kdp system is induced by low turgor pressure [85,102].…”

Section: Osmotolerancementioning

confidence: 99%

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Kashket¹

1987

FEMS Microbiology Letters

350

209

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Lactic acid bacteria maintain a cytoplasm that is more alkaline than the medium, but whose pH decreases as the medium is acidified during growth and fermentation. Streptococci generally acidify the cytoplasm from approximately pH 7.6 to 5.7 (external pH 4.5) before growth and then fermentation cease. The internal enzyme machinery of these anaerobic fermenters thus tolerates a fairly wide range in internal proton concentration. Lactobacilli tolerate a significantly more acidic cytoplasmic pH of 4.4 (external pH 3.5). However, when the cytoplasmic pH decreases below a threshold pH, which depends on the organism cellular functions are inhibited. Fermentation end‐products, such as organic acids or alcohols, exert their deleterious effects by bringing about acidification of the cytoplasm below the permissible pH. Organic acids, which act as protonophores, or solvents, which perturb membrane phospholipids, at high concentrations increase the inward leak of H+ so that H+ efflux is not rapid enough to alkalinize the cytoplasm. The membrane pH gradient is thus dissipated. A specific strain of Lactobacillus acidophilus has been found to be unusually osmotolerant. The osmoresistance is due to the cells' capacity to accumulate glycine betaine by a transport carrier that is activated, but not induced, by high medium osmotic pressure.

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Section: Osmotolerancementioning

confidence: 99%

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Kashket¹

1987

FEMS Microbiology Letters

350

209

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“…Investigations into the de nouo synthesis of compatible solutes have so far concentrated on non-halophilic bacteria like Escherichia coli and Rhizobium meliloti (Larsen et af., 1987;Smith & Smith, 1989), where the accumulation of glutamate and trehalose were observed, whilst proline and betaine were only used as osmotica when supplemented in the media (Grothe et al, 1986;Le Rudulier & Bernard, 1986; Smith et a/., 1988). Biosynthesis of proline under osmotic stress has only been reported for some halotolerant Bacillus species (Tempest et al, 1970;Whatmore et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Severin

Wohlfarth

Galinski

1992

Journal of General Microbiology

177

144

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The aim of this investigation was to perform an extensive screening using HPLC and I3C-NMR spectroscopy to disclose the spectrum of osmolytes produced by aerobic heterotrophic and anoxygenic phototrophic eubacteria. The most predominant solutes detected within a wide range of marine and halophilic micro-organisms were two recently discovered tetrahydropyrimidines ectoine and hydroxyectoine, which were synthesized in response to osmotic stress.

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“…Several authors have reported the formation of compatible solutes in the cytoplasm of cells grown under conditions of high osmotic pressure (Le Rudulier & Bernard, 1986;Czonka, 1989). At concentrations up to 1-3;/, NaCl growth of R. meliloti is not affected, while growth of R. leguminosarum biovar trifolii is impaired at 0.4% NaCl (Vincent, 1974).…”

Section: Introductionmentioning

confidence: 99%

Osmotically induced oligo- and polysaccharide synthesis by Rhizobium meliloti SU-47

Breedveld¹,

Zevenhuizen²,

Zehnder³

1990

Journal of General Microbiology

106

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In standard liquid medium containing 5 g mamitoll-' and 1 g glutamic acid 1-l, Rhizobium mefifoti SU-47 cells accumulated 350 mg cyclic 1,2-Q-glucans (g protein)-'. The cyclic glucans were 36 % glycerol-1-phosphatesubstituted and 64% were uncharged. In the same medium with 10 g mamitoll-' , repeating units of succinoglycan (1110 mg 1-l) were found as extracellular carbohydrates, and only low amounts of the succinoglycan polymer (up to 300 mg 1-l) were excreted. By raising the osmotic pressure of the medium by the addition of NaCl or other ionic and non-ionic osmolytes, succinoglycan production could be stimulated: up to 2.4 g 1-1 at 0.2 M-NaCI was produced at the expense of the repeating units. Above 0.2 M-NaCl growth was slowed down, and succinoglycan excretion diminished. At 1 M-NaCl growth stopped completely. In standard medium containing 0.6 M-NaCl the amount of cellular cyclic l,2-Q-glucans was lowered to 150 mg (g protein)-l out of which the glycerol-1-phosphatesubstituted glucan fraction was reduced to 15%. Instead, high amounts of oligosaccharides were synthesized as osmoprotectants, with trehalose as the major component [up to 200 mg (g protein)-']. Glycogen synthesis was completely suppressed at this salt concentration, while p l y Q-hydroxybutyric acid synthesis was unaffected.

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Salt tolerance in Rhizobium: A possible role for betaines

Cited by 30 publications

References 19 publications

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Osmotically induced oligo- and polysaccharide synthesis by Rhizobium meliloti SU-47

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