title: The effect of polymyxin B nonapeptide (PMBN) on transformation.
abstract: The effect of the outer membrane permeabilizing polycation, polymyxin B nonapeptide (PMBN) on the transformation of E. coli HB101 with pBR322 plasmid DNA was investigated. Pretreatment of cells with PMBN (followed by suspending the cells in PMBN-free medium) did not stimulate the development of competence induced by the calcium heat pulse. In the absence of calcium-ions, a high PMBN concentration (1 mM) was able to induce a low transformation frequency provided that PMBN was not removed before the addition of DNA.
mesh_terms: D002122:Calcium Chloride / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D006358:Hot Temperature; D010957:Plasmids; D011112:Polymyxin B / Q000031:analogs & derivatives / Q000494:pharmacology*; D011113:Polymyxins / Q000494:pharmacology*; D014170:Transformation, Genetic / Q000187:drug effects*
chemical_list: D004269:DNA, Bacterial; D011113:Polymyxins; C038934:polymyxin B nonapeptide; D011112:Polymyxin B; D002122:Calcium Chloride