COMPARATIVE-STUDY OF 2 EXTRACELLULAR PROTECTANTS SECRETED BY ESCHERICHIA-COLI-CELLS AT ELEVATED-TEMPERATURES

The regularities of the formation and action, as well as some physicoc hemical properties, of two extracellular protectants secreted by Esche richia coli cells under the condition of heat shock (a temperature inc rease from 37 to 46-49 degrees C), were investigated. Both factors, '' antilysin'' (factor X-I), either protecting from, or diminishing, cell lysis under the action of 9 mu M N-ethylmaleimide (NEM), and ''mu-red ucer'' (factor X-II), reducing the rate of culture growth after 60-min incubation and increasing culture viability in the presence of 200 mu M NEM, were shown to be low-molecular substances (less than 10 kDa), stable at extreme pH values (pH 1 and pH 11). Factors X-I and X-II dif fered in the dynamics of their accumulation in the culture liquid unde r unfavorable conditions and in the dependence pattern of their action upon concentration. Unlike factor X-II, factor X-I was highly unstabl e during heating and storage. By their characteristics, X-I should be considered a protectant, or an adaptogen of direct action, and X-II an inductor activating the cellular system to enhance cell viability.