| Abstract: | The 4.7 Kb EcoRI-fragment of phase I B. pertussis 475 (serovar 1.2.3) chromosome DNA carrying the pertussis toxin (PT) operon was cloned on vector plasmid pUC19 in Escherichia coli. Three fragments (1.14 Kb KpnI-PstI, 1.27 Kb PstI-PstI, and 0.96 Kb PstI-PstI) were obtained from the resulting hybrid plasmid, coded pRH119, by electrophoretic techniques and used as a combined molecular probe for analysis of the EcoRI-digested and PstI-digested chromosomal DNA of B. pertussis strain 475 in phase I, B. pertussis in phase IV, B. parapertussis strains 504 and 17903, B. bronchiseptica strain 214, and B. parapertussis strain 17903 (a convertant obtained by means of B. pertussis phage 134), as well as B. pertussis phage 134. Southern blot hybridization under the conditions of 100% DNA-DNA homology showed the presence of DNA sequences characteristic of the PT operon in all cases except the DNA of phage 134; moreover, the use of the above-mentioned probe made it possible to hybridize all EcoRI-fragments of chromosomal DNA, having the same molecular size (4.7 Kb). Consequently, the PT genes in the above Bordetella species were mapped in identical loci.(ABSTRACT TRUNCATED AT 250 WORDS) |
