The Physiological Bases for Microbial Barotolerance.
Technical rept. (Annual) no. 1, 1 Jun 72-31 May 73,
ROCHESTER UNIV N Y DEPT OF MICROBIOLOGY
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The aim of the project is to determine the biochemical and physiological bases for the wide variations in barotolerance among microorganisms. Hydrostatic pressure potentiates the growth inhibitory actions of acids and bases, and this potentiation appears to be related to membrane damage. The effect of pressure on protonation and deprotonation reactions is of considerable ecological significance in marine sediments where the ambient pressure is high and the pH is displaced from neutrality. Pressure inhibits bacterial motility both by inhibiting the activity of preformed flagella and by inhibiting the synthesis of new flagella. The latter process was found to be very sensitive to pressure, much more so than growth or protein synthesis in general. Other projects on which progress is reported include a study of the adverse effects of pressure on ATP supply in Streptococcus faecalis cells and the activation of the membrane ATPase of the bacterium by pressure a study of the potentiating effects of pressure on antibiotic action a study of the amelioration by deuterium oxide of the adverse effects of pressure on bacterial growth and attempts to isolate barotolerant bacterial variants. Modified author abstract