PLOIDY STUDIES ON THE LARGE CELLS OF MICROCOCCUS AUREUS

CARBOMYCIN REQUIRING MUTANTS OF MICROCOCCUS PYOGENES VAR. AUREUS

“…Similar large and pleomorphic forms of drug-resistant bacteria have been reported by many investigators (Hunter et al., 1950;Clark and Webb, 1955;Stempen, 1955). As suggested by Clark and Webb (1955), the "drug induced" large cells of Staphylococcus aureus may result from "intracellular nuclear fusion to yield a diploid or polyploid nucleus." The size and shape of the nucleus of the carbomycin dependent mutant is revealed in figure 3 following Lindegren's nuclear staining technique (Lindegren, 1942).…”

EFFECT OF SUCCESSIVE X-IRRADIATION ON NOCARDIA CORALLINA

“…The result of four successive irradiations of Micrococcus aureus is shown in figure 4. This culture was grown to yield haploid cells (Clark and Webb, 1955) and shows the stability of radiation resistance in a haploid cell.…”

CYTOGENETIC STUDY OF NOCARDIA CORALLINA ,

“…The comparisons revealed consistent and unequivocal differences in the nuclear appearance of these two forms but failed to explain the ploidy of the cultures on a cytological basis. Clark and Webb (1955a) studied the large cells of Micrococcus aureus cytologically and radiobiologically, and presented evidence for the diploid and triploid nature of these forms.…”