Abstract
It is possible that the methane oxidising bacteria M. capsulatus synthesise in the course of their development and secrete into the culture liquid extracellular metabolites – membranotropic autoregulatory factors d1 and d2 the synthesis of which had been observed earlier in other groups of microorganisms. It is shown that the physiological effect of the factor d2 is due to the influence of the fraction comprising free aliphatic acids and containing mainly palmitic and palmitoleic acids. One of the manifestations of the effect of the specific autoregulatory factor d1 as its concentration increases in the culture medium is the transition of the vegetative cells to a hypometabolic state. The active principle of the factor d1 is the lactone of 3-deoxypentonic acid. A practical use for the chemical analogues of the autoregulatory factors d1 and d2 is suggested. The bibliography includes 25 references.