title: Bacillus pumilus plasmid pPL10: properties and insertion into Bacillus subtilis 168 by transformation.
abstract: Bacillus pumilus ATCC 12140 harbors 10 or more copies per chromosome of each two small plasmids. Variants of this strain were isolated which were sensitive to a killing activity produced by the plasmid-containing parent. Each of 24 such sensitive (S) variants tested lacked detectable levels of supercoiled deoxyribonucleic acid. Transduction of S variants to the Kill+ phenotype was performed using phage PBP1 propagated on a mutant of ATCC 12140, designated strain L10, that remained Kill+ but retained only a single plasmid species (plasmid pPL10; molecular weight, approximately 4.4 X 10(6), approximately 20 copies per chromosome; RHO = 1.698). Resulting Kill+ transductants of S variants contained a single plasmid species having a size and copy number comparable to that of pPL10. Transfer of pPL10 from strain L10 TO B. pumilus strain NRS 576 was accomplished by transduction with selection for the Kill+ phenotype. Strain NRS 576 naturally harbors about two copies per chromosome of a 28-million-dalton plasmid, pPL576. In Kill + transductants of NRS 576, plasmids pPL10 and pPL576 stably coexisted at a ratio of about 11 molecules of pPL10 to 1 molecule of pPL576. Therefore, pPL576 and pPL10 are compatible plasmids. B. subtilis 168 is naturally resistant to pPl10- determined killing activity. Plasmid pPl10 was therefore inserted into B-subtilis 168 by transformation, using an indirect selection procedure and a spoB mutant as recipient. The plasmid is stably maintained at an estimated 10 copies per chromosome in the spore- recipient and in spore+ transformants. pPL10 is sensitive to cleavage by the endonucleases Hind III and EcoR1.
mesh_terms: D001407:Bacillus / Q000032:analysis*; D001412:Bacillus subtilis / Q000032:analysis* / Q000254:growth & development; D001435:Bacteriophages / Q000254:growth & development; D004269:DNA, Bacterial / Q000032:analysis; D004270:DNA, Circular / Q000032:analysis; D005111:Extrachromosomal Inheritance; D014644:Genetic Variation; D008242:Lysogeny; D010641:Phenotype; D010957:Plasmids; D014161:Transduction, Genetic; D014170:Transformation, Genetic
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular