title: Isolation and partial characterization of four plasmids from antibiotic-resistant thermophilic bacilli.
abstract: Twenty-nine antibiotic-resistant isolates of thermophilic bacilli were examined for the presence of covalently closed circular duplex DNA molecules by agarose-gel electrophoresis and caesium chloride-ethidium bromide density gradient centrifugation. Five of the 29 strains tested contained covalently closed circular molecules. Two of the streptomycin-resistant strains contained the same two plasmids: pAB118A of molecular weight 4.9 X 10(6) (7.0 kilobases) and pAB118B of molecular weight 3.0 X 10(6) (4.3 kilobases). Two of the tetracycline-resistant strains each contained a plasmid (pAB124) of molecular weight 2.9 X 10(6) (4.14 kilobases), while a third harboured a small plasmid (pAB128) of molecular weight 2.5 X 10(6) (3.57 kilobases). These plasmids were digested with 19 different restriction endonucleases and the numbers of cleavage sites were determined. Transformation of Bacillus subtilis (168 (Trp-) with purified plasmid DNA indicated that pAB124 conferred tetracycline resistance on the host.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001407:Bacillus / Q000032:analysis / Q000187:drug effects / Q000235:genetics*; D001412:Bacillus subtilis / Q000235:genetics; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification*; D004270:DNA, Circular / Q000032:analysis / Q000302:isolation & purification*; D006358:Hot Temperature; D011815:R Factors; D012722:Sewage; D014169:Transformation, Bacterial; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004270:DNA, Circular; D012722:Sewage; D004262:DNA Restriction Enzymes