[Detection of two new extracellular adaptogenic factors in Escherichia coli K-12].

The culture liquid of Escherichia coli K-12 was able to promote the adaptation of this bacterium to various stress factors. Exponentially growing E. coli cells were found to secrete an extracellular "factor of accelerated adaptation to new media," capable of shortening by several hours the lag phase of LB-grown cells transferred to minimal medium with glucose. At sublethal temperatures, E. coli cells secreted a "growth rate reducer," capable of slowing down the growth rate and enhancing the resistance of cells to bactericidal concentrations of N-ethylmaleimide. Such factors have not yet been described in the literature.