Synchronous cultures of Bacillus subtilis 168 M were obtained from light-density spores germinated at 46 C and grown at 37 C. This procedure synchronizes both cell division and chromosome replication. The chromosome synchrony was demonstrated by using transformation to measure changes in marker frequency during the cell cycle. The synthesis of two enzymes and of bacterial flagellar protein was ...

Polyploid organisms contain a number of chromosomes that is some multiple of x (basic chromosome number) greater than the 2 x content of related diploid species. Winkler (1916) introduced the term in a study of vegetative grafts in Solanum, when he discovered tetraploid plants regenerated from callus tissue on cut stems of diploid S. nigrum . Winge (1917) observed that interspecific hybrids giv...