Extrachromosomal DNA in Bacillus thuringiensis var. kurstaki, var. finitimus, var. sotto, and in Bacillus popilliae

Abstract

Four entomopathogenic bacteria contained extrachromosomal deoxyribonucleic acid (DNA) molecules of various sizes. Bacillus thuringiensis var. kurstaki contained twelve elements banding on agarose gels that ranged from 0.74 to > 50 × 10 6 daltons, three of which were giant extrachromosomal DNA elements. B. thuringiensis var. sotto contained one giant extrachromosomal DNA element with a molecular size of about 23.5 × 10 6 daltons and two lesser elements of 0.80 and 0.62 × 10 6 daltons. B. thuringiensis var. finitimus harbored two giant DNA elements corresponding to >50 × 10 6 daltons and two lesser bands with relative small size (0.98 and 0.97 × 10 6 daltons). B. popilliae contained no giant extrachromosomal DNA elements but did contain two smaller elements corresponding to 4.45 and 0.58 × 10 6 daltons. The possible use of extrachromosomal DNA elements that prove to be autonomous replicons for recombinant DNA studies is discussed.