Correlation of Hyperthermic Sensitivity and Membrane Microviscosity in<i>E. Coli</i>K1060

Dennis, Warren H.; Yatvin, Milton B.

doi:10.1080/09553008114550341

Cited by 37 publications

(20 citation statements)

References 13 publications

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“…These results support the hypothesis that fluidity has a greater effect in determining the resistance of exponential-phase cells than that of stationary-phase cells. It is worth noting that membrane fluidity affects cellular heat resistance in a manner that is opposite to its effect on pressure resistance, i.e., cells with more-fluid membranes are more heat sensitive (12,15,20).…”

Section: Vol 68 2002 Membrane Fluidity and Pressure Resistance Of Ementioning

confidence: 99%

Role of Membrane Fluidity in Pressure Resistance of Escherichia coli NCTC 8164

Casadei

Mañas

Niven

et al. 2002

Appl Environ Microbiol

200

119

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The relationship among growth temperature, membrane fatty acid composition, and pressure resistance was examined in Escherichia coli NCTC 8164. The pressure resistance of exponential-phase cells was maximal in cells grown at 10°C and decreased with increasing growth temperatures up to 45°C. By contrast, the pressure resistance of stationary-phase cells was lowest in cells grown at 10°C and increased with increasing growth temperature, reaching a maximum at 30 to 37°C before decreasing at 45°C. The proportion of unsaturated fatty acids in the membrane lipids decreased with increasing growth temperature in both exponential- and stationary-phase cells and correlated closely with the melting point of the phospholipids extracted from whole cells examined by differential scanning calorimetry. Therefore, in exponential-phase cells, pressure resistance increased with greater membrane fluidity, whereas in stationary-phase cells, there was apparently no simple relationship between membrane fluidity and pressure resistance. When exponential-phase or stationary-phase cells were pressure treated at different temperatures, resistance in both cell types increased with increasing temperatures of pressurization (between 10 and 30°C). Based on the above observations, we propose that membrane fluidity affects the pressure resistance of exponential- and stationary-phase cells in a similar way, but it is the dominant factor in exponential-phase cells whereas in stationary-phase cells, its effects are superimposed on a separate but larger effect of the physiological stationary-phase response that is itself temperature dependent

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Section: Vol 68 2002 Membrane Fluidity and Pressure Resistance Of Ementioning

confidence: 99%

Role of Membrane Fluidity in Pressure Resistance of Escherichia coli NCTC 8164

Casadei

Mañas

Niven

et al. 2002

Appl Environ Microbiol

200

119

View full text Add to dashboard Cite

show abstract

“…Bacterial cytoplasmic membranes consist mainly of lipids and have been shown to be a site for thermal injury (12,28,75). The cytoplasmic membrane represents the boundary between the cytoplasm and the external environment and regulates the flow of nutrients and metabolic products in and out of the cell, thereby permitting homeostasis of the cytoplasmic environment (10,35).…”

mentioning

confidence: 99%

Treatment ofSalmonella entericaSerovar Enteritidis with a Sublethal Concentration of Trisodium Phosphate or Alkaline pH Induces Thermotolerance

Balamurugan

Khachatourians

Korber

2004

Appl Environ Microbiol

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The responses of Salmonella enterica serovar Enteritidis to a sublethal dose of trisodium phosphate (TSP) and its equivalent alkaline pH made with NaOH were examined. Pretreatment of S. enterica serovar Enteritidis cells with 1.5% TSP or pH 10.0 solutions resulted in a significant increase in thermotolerance, resistance to 2.5% TSP, resistance to high pH, and sensitivity to acid and H 2 O 2 . Protein inhibition studies with chloramphenicol revealed that thermotolerance, unlike resistance to high pH, was dependent on de novo protein synthesis. Two-dimensional polyacrylamide gel electrophoresis (PAGE) of total cellular proteins from untreated control cells resolved as many as 232 proteins, of which 22 and 15% were absent in TSP-or alkaline pH-pretreated cells, respectively. More than 50% of the proteins that were either up-or down-regulated by TSP pretreatment were also up-or down-regulated by alkaline pH pretreatment. Sodium dodecyl sulfate-PAGE analysis of detergent-insoluble outer membrane proteins revealed the up-regulation of at least four proteins. Mass spectrometric analysis showed the up-regulated proteins to include those involved in the transport of small hydrophilic molecules across the cytoplasmic membrane and those that act as chaperones and aid in the export of newly synthesized proteins by keeping them in open conformation. Other up-regulated proteins included common housekeeping proteins like those involved in amino acid biosynthesis, nucleotide metabolism, and aminoacyl-tRNA biosynthesis. In addition to the differential expression of proteins following TSP or alkaline pH treatment, changes in membrane fatty acid composition were also observed. Alkaline pH-or TSP-pretreated cells showed a higher saturated and cyclic to unsaturated fatty acid ratio than did the untreated control cells. These results suggest that the cytoplasmic membrane could play a significant role in the induction of thermotolerance and resistance to other stresses following TSP or alkaline pH treatment.

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“…When the irradiation was performed under hypoxic conditions a small increase in radioresistance was observed. As expected [8], linolenic acid grown bacteria are more heat sensitive than oleic acid grown bacteria. Both types of 100- supplemented cells are more thermoresistant after 10 mM DEM treatment (Fig.…”

Section: Resultsmentioning

confidence: 67%

Radio- and thermosensitivity of E. coli K1060 after thiol depletion by diethylmaleate

Konings

Gipp

Yatvin

1984

Radiat Environ Biophys

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The Escherichia coli auxotroph K1060 has been grown in a medium supplemented with either oleic acid (18:1) or linolenic acid (18:3) and its radiosensitivity and thermosensitivity established using bacterial cell survival as the assay system. No difference in radiosensitivity was observed when oleic and linolenic grown cells were exposed to gamma-radiation at room temperature. When heated at 49 degrees C linolenic grown cells were more sensitive than oleic grown cells. To investigate whether soluble -SH compounds, e.g., glutathione (GSH), were critical in protecting cells against radiation or heat, studies were performed using cells depleted of -SH by incubation with diethylmaleate (DEM). After reduction of water-soluble non-protein thiol compounds to 25% (10 mM DEM treatment) of control value, no major changes in radiosensitivity under oxic conditions were found. Radioresistance increased slightly when irradiation was performed under hypoxic conditions. Thermoresistance was clearly stimulated after DEM treatments between 1 and 10 mM DEM. The main conclusion of these experiments is that lowering the cellular level of reduced glutathione may not generally be correlated with a higher radio- and thermosensitivity.

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Correlation of Hyperthermic Sensitivity and Membrane Microviscosity inE. ColiK1060

Cited by 37 publications

References 13 publications

Role of Membrane Fluidity in Pressure Resistance of Escherichia coli NCTC 8164

Role of Membrane Fluidity in Pressure Resistance of Escherichia coli NCTC 8164

Treatment ofSalmonella entericaSerovar Enteritidis with a Sublethal Concentration of Trisodium Phosphate or Alkaline pH Induces Thermotolerance

Radio- and thermosensitivity of E. coli K1060 after thiol depletion by diethylmaleate

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