[Cloning of the genes of hemolytic factors of Bordetella pertussis in Escherichia coli].

The gene library of B. pertussis strain No. 475 (serovar 1. 2. 3.) was obtained on plasmid pUC19 in E. coli strain JM107. The average size of the cloned fragments of chromosomal DNA was 4.9 Kb. Out of 1,700 tested recombinant clones, six caused visible hemolysis on petri dishes with agar containing 4% of sheep red blood cells after 16-hour incubation at 37 degrees C. Only two out of four isolated plasmids were similar in Pst I restriction. Consequently, the existence of several different genes responsible for the hemolytic factors of B. pertussis may be assumed. None of the cloned fragments had Hind III sites. Clones harboring hybrid plasmids possessed different modes of hemolysis, which may be indicative of gene expression in E. coli.