title: Isolation of plasmid deoxyribonucleic acid from two strains of Bacteroides.
abstract: Two clinical isolates of Bacteroides contained covalently closed circular deoxyribonucleic acid (DNA) as shown by sedimentation in an alkaline sucrose gradient, CsCl ethidium bromide equilibrium centrifugation, and electron microscopy. Bacteriodes fragilis N1175 contained a homogeneous species of plasmid DNA with a molecular weight of 25 x 10(6). Bacteroides ochraceus 2228 contained two distinct, covalently closed circular DNA elements. The larger cosedimented with the covalently closed circular DNA form of the R plasmid, R100, corresponding to a molecular weight of 70 x 10(6); the smaller sedimented as a 58S molecule with a calculated molecular weight of 25 x 10(6). The roles of these plasmids are unknown. Neither strain transferred antibiotic resistance to plasmid-negative Bacteroides or Escherichia coli, and neither produced bacteriocins active against other Bacteroides or sensitive indicator strains of E. coli.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001430:Bacteriocins / Q000096:biosynthesis; D001439:Bacteroides / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D001441:Bacteroides fragilis / Q000032:analysis* / Q000187:drug effects* / Q000378:metabolism; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000302:isolation & purification; D004270:DNA, Circular / Q000302:isolation & purification; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D005111:Extrachromosomal Inheritance; D008970:Molecular Weight; D010957:Plasmids; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004269:DNA, Bacterial; D004270:DNA, Circular; D013752:Tetracycline