The heating of S. aureus MF-31 and S. typhimurium 7136 at 52C and 48C respectively, produced a sublethal heat injury. When injured cells were placed in fresh growth medium they recovered. The recovery of S. aureus was not inhibited by chloramphenicol. The metabolic activities of tricarboxylic acid (TCA) cycle enzymes, as well as other selected enzymes in crude extracts of normal and heat-injured cells of both microorganisms were assayed. In extracts from S. typhimurium there was some loss of specific activity with fumarate hydratase, glutamate dehydrogenase, fructose diphosphate aldolase, lactate dehydrogenase, and the NAD(P) oxidases as a result of heating. In extracts from S. aureus oxoglutarate dehydrogenase, malate dehydrogenase and lactate dehydrogenase were severely inactivated after heating. Other enzymes in comparison were only moderately sensitive to heat. No significant increase in enzyme activity was observed in extracts from injured cells of either microorganism. Re-naturation of lactate dehydrogenase and malate dehydrogenase occurred during the recovery of S. aureus both in the presence and absence of chloramphenicol. No renaturation of oxoglutarate dehydrogenase was found under the same conditions.
No takes yet. Share an insight, caveat, or question.
Tomlins et al. (1971) studied this question.