[Osmotic modification of thermal damage in Escherichia coli bacteria at various pH values of the media].
A study was made of the influence of media with different osmotic pressure on cell survival and on optic density of supernatants from Escherichia coli B/r and E. coli Bs-1 cell suspensions heated under different pH values of media. Hyperthermia induced cell death accompanied with the loss of optically active (lambda = 260 nm) material. Both cell damage effects were increased in acid and alkaline conditions, compared to neutral condition of heating. Hypertonic media results in a decrease in thermic cell death and loss of cell substances. Under this condition, the protection influence of high osmotic pressure was seen to increase significantly in acid and alkaline conditions of heating, compared to neutral condition. It has been proposed that a higher thermal damage of microorganisms in acid and alkaline beating conditions and protection influence of hypertonic media, especially expressed in acid and alkaline medium, is caused to a great extent by the status of osmotic cell homeostasis.
Morozov
I I
II
Medical Radiology Research Centre, Russian Academy of Medical Sciences, Obninsk.
Petin
V G
VG
D003470:Culture Media; D004926:Escherichia coli / Q000502:physiology*; D018869:Heat-Shock Response; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D009997:Osmotic Pressure
D003470:Culture Media