title: Mapping of transfer and H pilus coding regions of the IncHII plasmid pHH1508a.
abstract: The IncHII plasmid pHH1508a (208 kilobases) encodes resistance to potassium tellurite, trimethoprim, and streptomycin. Conjugative pili encoded by pHH1508a were isolated, purified, and used for preparation of anti-H pilus antiserum. Immuno-gold labelling experiments using H pilus specific antiserum showed that antigenic determinants were located along the entire length of the H pilus. Immuno-gold labelling and lysis studies using pilH alpha, a bacteriophage specific for H pili, were used to investigate transfer-deficient mutants of pHH1508a obtained by Tn5 mutagenesis and an in vitro constructed derivative of 96 kilobases, pDT1178, which also conferred resistance to potassium tellurite, trimethoprim, and streptomycin. The transfer-deficient mutants did not specify H pili, whereas pDT1178, which transferred at low frequency (1 x 10(-4) transconjugants per recipient), specified a small number of H pili. A naturally occurring plasmid, pMG110, was found to encode the production of H pili, but was completely transfer deficient (less than 1 x 10(-7) transconjugants per recipient). This study suggests that genes required for H pilus production and assembly as well as low level transfer are located separately within the 96-kilobase fragment of pDT1178 and that other genes, located outside this region, are essential for the regulation and full expression of conjugative transfer.
authors: Department of Medical Microbiology and Infectious Diseases, University of Alberta, Edmonton, Canada.
authors: W
authors: W
authors: Yan
authors: D E
authors: DE
authors: Taylor
mesh_terms: D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D004352:Drug Resistance, Microbial / Q000235:genetics; D000939:Epitopes / Q000032:analysis; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000276:immunology / Q000648:ultrastructure; D010861:Fimbriae, Bacterial / Q000276:immunology* / Q000648:ultrastructure; D007106:Immune Sera / Q000276:immunology; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009154:Mutation; D011815:R Factors; D015183:Restriction Mapping; D013307:Streptomycin / Q000494:pharmacology; D013691:Tellurium / Q000494:pharmacology; D014295:Trimethoprim / Q000494:pharmacology
chemical_list: D004251:DNA Transposable Elements; D000939:Epitopes; D007106:Immune Sera; C026899:potassium tellurate(IV); D014295:Trimethoprim; D013691:Tellurium; D013307:Streptomycin