[Morphological and physiological peculiarities of spherical (11r) mutants of Escherichia coli K12].

A study was made of morphology, character and the rate of reproduction in 8 11r mutants obtained from Hfr and F--strains of E. coli K12 under the effect of N-nitroso-N-methylurea. The capacity of 11r mutants to realize several types of reproduction: transverse division, budding, asymmetrical division, and formation of granular forms was demonstrated. The rate of cell division, total DNA, RNA and protein synthesis were lower at the phase of rest and early exponential growth phase in the 11r mutants than in the parent cultures. Hyperosmotic conditions created by various stabilizers, media with increased viscosity and of different chemical composition, and also cell wall hydrolysate and their precursors failed to stimulate the 11r mutant reversion. A change of morphology, but not the reversion was seen on the media containing glycine and penicillin. Reversion was spontaneous with low frequency; it was observed in induction of inverse mutations with N-nitroso-N-methylurea.