Induced enzyme synthesis in cell-free preparations of Escherichia coli

Biochemical and cytological observations during the reversing process from spheroplasts to rod-form cells in Escherichia coli

Hirokawa, Hideo (National Institute of Health, Tokyo, Japan). Biochemical and cytological observations during the reversing process from spheroplasts to rod-form cells in Escherichia coli. J. Bacteriol. 84:1161-1168. 1962.-Spheroplasts of Escherichia coli B-054 were formed by penicillin, and the reversing process from spheroplasts to rod-form cells was examined. The amount of DNA, RNA, and protein in a single spheroplast increased to four to five times more than that of a rod-form cell during the spheroplast formation. Ultraviolet-absorptive particles, probably nuclei, were localized in several regions within a spheroplast. Morphological changes during the process of spheroplast reversion to rod-form cells were precisely followed. The number of rod-form cells, determined by colony counting according to the time course of reversion, increased very rapidly from the beginning of reversion, without a lag phase. From this evidence, it was concluded that a single spheroplast germinates into several rod-form cells.