title: Characterization of pili expressed by Haemophilus ducreyi.
abstract: Twelve strains of Haemophilus ducreyi isolated primarily from chancroid outbreaks in North America were examined for the presence of pili by transmission electron microscopy. We identified piliated cells in 10 of the 12 strains. Pilin extracts were prepared from the mechanically sheared cells of the 12 H. ducreyi strains as well as the stably piliated H. influenzae strain R890 and its non-piliated parent R906. Pili were present in 12 out of 12 H. ducreyi extracts and in the R890 extract but not in the R906 preparation. Pili were purified by cycles of differential pH solubilization and crystallization. In SDS-PAGE, the preparation consisted predominantly of a protein whose apparent relative molecular mass was 24,000 (24 k), and an electron micrograph showed that the preparation contained pili. Three H. ducreyi strains were passed 52 times on agar plates, and extracts prepared from these strains contained pili. There was no evidence of binding of erythrocytes obtained from nine mammalian and avian species to colonies of one of the stably piliated H. ducreyi strains. We conclude that H. ducreyi expressed pili, that the relative molecular mass of the pilin monomer was 24 k, that pilus expression was not readily lost in passage and that H. ducreyi pili may not bind to an erythrocyte receptor.
authors.affiliation: Department of Medicine, School of Medicine, State University of New York, Buffalo.
authors.forename: S M
authors.initials: SM
authors.lastname: Spinola
authors.forename: A
authors.initials: A
authors.lastname: Castellazzo
authors.forename: M
authors.initials: M
authors.lastname: Shero
authors.forename: M A
authors.initials: MA
authors.lastname: Apicella
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D002602:Chancroid / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000648:ultrastructure*; D006191:Haemophilus ducreyi / Q000145:classification / Q000648:ultrastructure*; D006382:Hemadsorption; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: C095247:24kDa surface protein, Haemophilus ducreyi; D000596:Amino Acids; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D036781:Fimbriae Proteins