Physical Properties of Three Plasmids and the Presence of Interrelated Plasmids in Bacillus popilliae and Bacillus lentimorbus

Abstract

Three plasmids, pBP68, pBP88, and pBP94 (molecular sizes 6750 ± 100, 8810 ± 90, and 9420 ± 30 bp, respectively), have been identified in Bacillus popilliae strains KLN 4, NRRL B-2524, BpPa (Vm r), and Ch 1 and characterized by physical mapping and hybridization analysis. In addition, a single-stranded DNA form for each plasmid has been observed in plasmid preparations. No similarity between the three plasmids was evident from comparisons of restriction endonuclease maps. However, hybridization analysis showed that the plasmids shared regions of sequence homology and that pBP88 is possibly a chimera of pBP68 and pBP94. Hybridization of pBP68, pBP88, pBP94, and Bacillus lentimorbus KLN 2 plasmid DNA to other plasmids present in B. popilliae and B. lentimorbus suggested that an interrelated family of plasmids exists in these two microorganisms.