[Biology of spheroplast- and protoplast-like types of L-forms of Escherichia coli K12 converted with penicillin].

A total of 21 strains of stable L-forms were obtained under the action of penicillin on various Hfr and F- strains of E. coli K12. Three morphological types of the L-forms obtained differed by the character of the cell elements, sensitivity to chemical agents, antibiotics and to T4 and T6 phages. Cell wall was revealed in one type of the L-forms, but the rest L-form types were devoid of the cell walls. Reference of the L-forms which preserved the cell wall to the spheroplastic type, and the L-forms devoid of the cell wall to the protoplastic type is suggested. A possibility of L-forms of spheroplastic type obtained from the Hfr strains to retain the sensitivity to f2 phage and to transmit their chromosomes to bacterial recipients in conjugation was demonstrated. The results obtained are discussed.