Cell Division in Micrococcus Pyogenes Var. Aureus

PLOIDY STUDIES ON THE LARGE CELLS OF MICROCOCCUS AUREUS

“…In no case was any clear evidence of "classical mitosis or meiosis" observed, and the additional stain work supported the earlier concept (Webb and Clark, 1954) that the nuclear membrane normally remains intact during nuclear division in bacteria. A similar concept has also been postulated by DeLamater (1954).…”

“…Lindegren (1942) presented cytological evidence for a meiotic division in Micrococcus orchraceous. Webb and Clark (1954) found evidence of a diploid or polyploid phase in a life cycle of M. aureus. These large cells appeared cytologically to undergo a meiotic division to yield normal haploid cells.…”

“…on September 30, 2020 by guest http://jb.asm.org/ Downloaded from nuclear stain (Webb and Clark, 1954) except that no cell plates were stained. The nucleus appeared elliptical in resting cells and became round prior to division.…”

“…Clumps were broken up as indicated in "Materials and Methods" and no culture was used in an irradiation experiment unless it revealed at least 90 per cent single cells. "Multicellularity" has been shown to occur in M. aureus and multinuclearity also can exist (Webb and Clark, 1954). The extent of "multicellularity" was checked on all suspensions by the cell wall stain and was found to be less than 1 per cent after 24 hours' incubation, and normally from 5 to 20 per cent in young cultures; however, under certain conditions the percentage was found to exceed 50.…”

ELECTRON MICROSCOPY OF ULTRATHIN SECTIONS OF SCHIZOSACCHAROMYCES OCTOSPORUS I

“…There are no indications of the prior formation of a cell plate as described in bacteria (Knaysi, 1941(Knaysi, , 1949; Chance, 1953;Webb and Clark, 1954;Bisset, 1955;Clark et al, 1957). The position of various cytoplasmic inclusions within the region of cross wall formation, and absence of an observable cross plate supports this contention.…”