Characterization of chromosomal and membrane associated plasmid in Bacillus brevis ATCC 9999.

Abstract
A covalently closed circular(ccc)DNA, with MW of 44.7 .times. 106 daltons, was isolated from B. brevis ATCC 9999 (a gramicidin S producer) and from the gramicidin S-negative mutant EB16. The cccDNA in the case of the parent strain is mainly (99%) attached to the chromosomal and membrane fraction. A restriction enzyme map of the plasmid DNA was constructed for the enzymes SalI, SmaI and BamHI, which cleaved the plasmid DNA into 2, 2 and 6 fragments, respectively. Further digestion with the endonucleases EcoRI and HindIII cleaved the plasmid into 17 and 22 fragments.