       Document 0592
 DOCN  M9620592
 TI    Characterization of the hemolytic activity of Haemophilus ducreyi.
 DT    9602
 AU    Totten PA; Norn DV; Stamm WE; Department of Medicine, University of
       Washington, Seattle 98104,; USA.
 SO    Infect Immun. 1995 Nov;63(11):4409-16. Unique Identifier : AIDSLINE
       MED/96029737
 AB    H. ducreyi is the causative agent of chancroid, a genital ulcer disease
       most prevalent in developing countries. Chancroid enhances the
       heterosexual transmission of human immunodeficiency virus and is
       identified in focal outbreaks in the United States, but little is known
       about its pathogenesis. We studied the hemolysin produced by H. ducreyi
       because this molecule might be an important virulence factor in the
       pathogenesis of chancroid. Ten strains of H. ducreyi were tested on
       newly devised blood agar plates and were found to have hemolytic
       activity. We examined the hemolytic activity of H. ducreyi 35000 further
       and found that it was heat labile, cell associated, greatest at pH 7.0,
       and produced in logarithmic- but not stationary-phase cultures. Using
       transposons Tn916 and Tn1545-delta 3, we have isolated three classes of
       transposon mutants of strain 35000: those with no detectable hemolytic
       activity, those with reduced hemolytic activity, and those with enhanced
       hemolytic activity. Transposon insertions in the nonhemolytic mutants
       were located in a DNA sequence which hybridized to the Proteus mirabilis
       hemolysin gene. Analysis of clones containing overlapping sections of
       this region served to further localize the H. ducreyi hemolysin gene and
       allow its expression in Escherichia coli and complementation of the
       nonhemolytic defect in an H. ducreyi mutant. These experiments indicate
       that H. ducreyi 35000 produces a hemolysin that is related to the
       calcium-independent hemolysin produced by P. mirabilis. Further
       experiments are needed to define the similarity of the H. ducreyi
       hemolysin to other calcium-independent hemolysins and to determine its
       role in the pathogenesis of chancroid.
 DE    Cloning, Molecular  DNA Insertion Elements  Genes, Structural, Bacterial
       Genetic Complementation Test  Haemophilus
       ducreyi/GENETICS/*PATHOGENICITY  Hemolysins/*GENETICS  Hemolysis
       Mutagenesis  Restriction Mapping  Support, U.S. Gov't, P.H.S.  JOURNAL
       ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

