The Influence of NaCl Concentration of the Medium on the Potassium Content of Aerobacter aerogenes and on the Inter-relationships between Potassium, Magnesium and Ribonucleic Acid in the Growing Bacteria

Tempest, D. W.; Meers, J.

doi:10.1099/00221287-54-3-319

Cited by 47 publications

(15 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(These calculations assume that cytoplasmic MOPS is 70% anionic [11].) The amounts of Mg2+ and nucleic acid, the other major ionic species in the cytoplasm, also do not appear to vary with external osmolarity (12,23,49). The invariance of the excess cationic charge of osmotically regulated cytoplasmic solutes with accumulation of osmoprotectants argues against a variation in the cytoplasmic amounts of inorganic ions other than K+.…”

Section: Discussionmentioning

confidence: 99%

Origins of the osmoprotective properties of betaine and proline in Escherichia coli K-12

1992

View full text Add to dashboard Cite

The amounts of cytoplasmic water and of all osmotically significant cytoplasmic solutes were determined for Escherichia coli K-12 grown in 3-(N-morpholino)propane sulfonate (MOPS)-buffered glucose-minimal medium containing 0.5 M NaCl in the presence and absence of the osmoprotectants betaine and proline. The goal of this work is to correlate the effects of osmoprotectants on the composition of the cytoplasm with their ability to increase the growth rate of osmotically stressed cells. At a concentration of 1 mM in the growth medium, betaine increases the growth rate more than does proline; choline, which is converted to betaine by E. coli, appears to have an intermediate effect on growth rate. The accumulation of either betaine or proline reduces the cytoplasmic amounts of K+, glutamate, trehalose, and MOPS (the major cytoplasmic osmolytes accumulated in the absence of osmoprotectants), so that at this external osmolarity the total amount of cytoplasmic solutes is essentially the same in the presence or absence of either osmoprotectant. More betaine than proline is accumulated, so the extent of replacement of cytoplasmic solutes is greater for betaine than for proline. Accumulation of these osmoprotectants is accompanied by a large (20 to 50%) increase in the volume of cytoplasmic water per unit of cell dry weight (Vcyt.). This effect, which appears to result from an increase in the volume of free water, V. (as opposed to water of hydration, or bound water), is greater for betaine than for proline. Taken together, these results indicate that the molar effects of betaine and proline on water activity and on the osmotic pressure of the cytoplasm must be significantly larger than those of the solutes they replace. Biol. 222:281-300, 1991) observed that, in cells grown in the absence of osmoprotectants, both growth rate and Vcyt. decreased, whereas the amount of cytoplasmic K+ (nK+) increased, with increasing external osmolarity. We predicted that the observed changes in nK+ and Vcyto would have large and approximately compensating effects on key proteinnucleic acid interactions of gene expression, and we proposed that Vf was the fundamental determinant of growth rate in osmotically stressed cells. The properties of cells cultured in the presence of betaine and proline appear completely consistent with our previous work and proposals. Accumulation of betaine and, to a lesser extent, proline shifts the set of linked physiological parameters (nK+, Vcyto, growth rate) to those characteristic of growth at lower osmolarity in the absence of osmoprotectants. Models for the thermodynamic basis and physiological consequences of the effect of osmoprotectants on Vcyt. and Vf are discussed.Living cells adapt to osmotic stress by varying the intracellular concentration (i.e., thermodynamic activity) of osmotically active solutes (osmolytes). A variety of organisms accumulate the so-called osmoprotectants betaine and proline to prevent dehydration when placed under the stress of high-osmolarity environments (16,22,43,45,52). ...

show abstract

Section: Discussionmentioning

confidence: 99%

Origins of the osmoprotective properties of betaine and proline in Escherichia coli K-12

1992

View full text Add to dashboard Cite

show abstract

“…Possibly high external K+ concentrations may slow down the K+ loss from damaged cells. The K+ ion pool concentration is related to the medium sodium chloride content (21). High external sodium chloride concentrations may therefore magnify the physiological consequences of K+ loss from the osmoregulatory pool.…”

Section: Discussionmentioning

confidence: 99%

Influence of Suspending Media upon the Susceptibility of Pseudomonas aeruginosa NCTC 6750 and Its Spheroplasts to Polymyxin B

Klemperer

Gilbert

Meier

et al. 1979

Antimicrob Agents Chemother

View full text Add to dashboard Cite

The lytic and bactericidal actions of polymyxin B on whole cells and spheroplasts of Pseudomonas aeruginosa varied markedly with the suspending media, and there was little correlation between them. Relative rates of lysis of these preparations and also of Bacillus megaterium protoplasts suggested that polymyxin causes progressive damage to the cytoplasmic membrane, such that membrane permeability towards various ions increased as follows: K + > Na + > NO 3 − > Cl − , Ca 2+ , H 2 PO 4 − /HPO 4 2− . Impermeant compounds, such as NaCl and sucrose, protected whole cells against lysis but not against death. It is suggested that lysis of whole cells by polymyxin is a secondary effect, resulting from entry of solutes normally excluded by the cytoplasmic membrane and the fragility of the damaged outer membrane. Because the degree of lysis varies with the external solutes, it should be treated with caution as a descriptor of polymyxin activity.

show abstract

“…The above mentioned adsorption experiments were made with organisms grown in Mg2+-limited culture only; but since the wall composition of organisms is known to vary with the chemical nature of the environment (Ellwood & Tempest, 1967;Tempest, Dicks & Ellwood, I 968), it was of interest to determine whether the affinity with which organisms bound Mg2+ at their surfaces also varied with changes in the nature of the growth limitation. In this connexion, Tempest & Meers (1968) reported that A. aerogenes had a lower tolerance for NaCl when its growth was limited by Mg2+ availability than when its growth was limited by the availability of any other essential nutrient. This suggested that sodium ions impeded Mg2+ assimilation, possibly by competing for adsorption sites on the bacterial surface.…”

Section: Introductionmentioning

confidence: 99%

“…A preliminary account of this work has been published (Meers & Tempest, 1969 Growth conditions. Organisms were grown in 0.5 1. chemostats (Herbert, Phipps & Tempest, 1965) in the simple salts media described by Tempest & Meers (1968) and by . The chemostat was operated at a dilution rate of 0.3 h.-l and at a temperature of 35"; the pH value was automatically maintained throughout at pH 7-0 f 0.05.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Growth-limiting Substrate and Medium NaCl Concentration on the Synthesis of Magnesium-binding Sites in the Walls of Bacillus subtilis var. niger

Meers¹,

Tempest²

1970

Journal of General Microbiology

Self Cite

View full text Add to dashboard Cite

A comparative study has been made of the influence of growth environment on the properties of the walls of Bacillus subtilis var. niger organisms, particularly with respect to ability to bind magnesium ions. The medium NaCl concentration and the nature of the growth-limiting substrate, in chemostat cultures, both affected markedly the subsequent affinity and capacity of the bacterial walls for Mg2+ adsorption. These changes correlated with differences in the phosphate content of the walls, which in turn related largely to changes in wall teichoic acid content. Thus it seemed that whenever a constraint to the adsorption of Mg2+ was applied (either by growing the organisms in a Mg2+-limited environment, or in one containing high concentrations of a competing ion), walls were synthesized that had an increased teichoic acid content and an increased affinity for magnesium ions. These results support the thesis that anionic polymers in the walls of Bacillus organisms (i.e. teichoic acids and teichuronic acids) are involved in cation assimilation.

show abstract

The Influence of NaCl Concentration of the Medium on the Potassium Content of Aerobacter aerogenes and on the Inter-relationships between Potassium, Magnesium and Ribonucleic Acid in the Growing Bacteria

Cited by 47 publications

References 13 publications

Origins of the osmoprotective properties of betaine and proline in Escherichia coli K-12

Origins of the osmoprotective properties of betaine and proline in Escherichia coli K-12

Influence of Suspending Media upon the Susceptibility of Pseudomonas aeruginosa NCTC 6750 and Its Spheroplasts to Polymyxin B

The Influence of Growth-limiting Substrate and Medium NaCl Concentration on the Synthesis of Magnesium-binding Sites in the Walls of Bacillus subtilis var. niger

Contact Info

Product

Resources

About