Determination of turgor pressure in Bacillus subtilis: a possible role for K+ in turgor regulation

Whatmore, Adrian M.; Reed, Robert H.

doi:10.1099/00221287-136-12-2521

Cited by 200 publications

(165 citation statements)

References 16 publications

(8 reference statements)

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“…This phenomenon is probably connected with the maintenance of the very high turgor found in B. subtilis (55). The maintenance of high turgor would most likely favor the accumulation of osmotically active solutes compatible with the normal functioning of the cell instead of ionic osmolytes which are deleterious at high concentrations (4,15,29).…”

Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5127mentioning

confidence: 99%

“…Exposure of Bacillus subtilis to a hypersaline environment incites an integrated physiological adaptation reaction that is aimed at restoring the disturbed cellular water balance, maintaining optimal turgor, and protecting cell components from the detrimental effects of high ionic strength. It consists of an initial rapid influx of K ϩ ions and the onset of increased proline biosynthesis (54,55). In addition, the expression of a general stress regulon that is also responsive to other growth-limiting conditions and to stationary-phase signals is induced (20).…”

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confidence: 99%

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Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

et al. 1996

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Synthesis of the osmoprotectant glycine betaine from the exogenously provided precursor choline or glycine betaine aldehyde confers considerable osmotic stress tolerance to Bacillus subtilis in high-osmolarity media. Using an Escherichia coli mutant (betBA) defective in the glycine betaine synthesis enzymes, we cloned by functional complementation the genes that are required for the synthesis of the osmoprotectant glycine betaine in B. subtilis. The DNA sequence of a 4.1-kb segment from the cloned chromosomal B. subtilis DNA was established, and two genes (gbsA and gbsB) whose products were essential for glycine betaine biosynthesis and osmoprotection were identified. The gbsA and gbsB genes are transcribed in the same direction, are separated by a short intergenic region, and are likely to form an operon. The deduced gbsA gene product exhibits strong sequence identity with members of a superfamily of specialized and nonspecialized aldehyde dehydrogenases. This superfamily comprises glycine betaine aldehyde dehydrogenases from bacteria and plants with known involvement in the cellular adaptation to high-osmolarity stress and drought. The deduced gbsB gene product shows significant similarity to the family of type III alcohol dehydrogenases. B. subtilis mutants with defects in the chromosomal gbsAB genes were constructed by marker replacement, and the growth properties of these mutant strains in high-osmolarity medium were analyzed. Deletion of the gbsAB genes destroyed the cholineglycine betaine synthesis pathway and abolished the ability of B. subtilis to deal effectively with high-osmolarity stress in choline-or glycine betaine aldehyde-containing medium. Uptake of radiolabelled choline was unaltered in the gbsAB mutant strain. The continued intracellular accumulation of choline or glycine betaine aldehyde in a strain lacking the glycine betaine-biosynthetic enzymes strongly interfered with the growth of B. subtilis, even in medium of moderate osmolarity. A single transcription initiation site for gbsAB was detected by high-resolution primer extension analysis. gbsAB transcription was initiated from a promoter with close homology to A -dependent promoters and was stimulated by the presence of choline in the growth medium.

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Section: Vol 178 1996 Glycine Betaine Synthesis In B Subtilis 5127mentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

et al. 1996

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“…Bacillus subtilis NCIB 1650, obtained from the National Collection of Industrial Bacteria, Aber: deen, UK, was routinely maintained on nutrient agar at 25 "C. The defined liquid medium used in this study is described in the preceding paper (Whatmore & Reed, 1990); the K+-free medium used was as above with the omission of the KCl. All experimental flasks were inoculated with exponentially growing cultures (10 h).…”

Section: Methodsmentioning

confidence: 99%

“…Cells were sized and counted using a Coulter counter (ZBI) and ClOOO Channelyzer linked to an Acorn microcomputer as described by Whatmore & Reed (1990).…”

Section: Methodsmentioning

confidence: 99%

The effects of osmotic upshock on the intracellular solute pools of Bacillus subtilis

Whatmore

Chudek²,

Reed

1990

Journal of General Microbiology

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260

335

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The effects of hypersaline treatment (osmotic upshock) on solute accumulation have been studied in the Grampositive bacterium BaciZZus subtiZis. Natural abundance 3C NMR spectroscopy studies revealed only proline as a major organic osmoticum in cells grown in defined medium (no exogenous organic solutes) and this finding was confirmed by amino acid analysis. Intracellular concentrations of both K+ and proline rose markedly after osmotic upshock. K+ influx from the medium was rapid (< 1 h) but proline synthesis was a slower process (5-9 h). Proline synthesis appeared to be dependent on the prior accumulation of K+ and it is possible that K+ serves in some manner as the signal for increased proline synthesis. In cells upshocked in medium enriched in glycine betaine the endogenous synthesis of proline was repressed and glycine betaine served as the sole organic osmoticum. K+ was also accumulated under these conditions.

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“…This osmotic pressure gradient is counterbalanced by a hydrostatic pressure differential (turgor) [23] that enables the cell to enlarge during growth [26]. Gram-positive cells, such as Bacillus subtilis, the host for phage SPP1, have much higher turgor: ∼19 atm [27]. When the cell membrane is breached by an infecting phage, a new conduit opens up for water to enter from the environment into the cell cytoplasm by passing through the phage capsid.…”

Section: Hydrodynamic Model For In Vivo Ejectionmentioning

confidence: 99%

Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

2013

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A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution or culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection in vivo; the mechanism is perfectly consistent with phage genome ejection in vitro.

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Determination of turgor pressure in Bacillus subtilis: a possible role for K+ in turgor regulation

Cited by 200 publications

References 16 publications

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

The effects of osmotic upshock on the intracellular solute pools of Bacillus subtilis

Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

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