RESUMO
It has been the purpose of this paper to study molecular-biological features of the Bordetella bacteriophage interaction with the host cell during lysogeny and conversion as well as to determine the degree of homology between genomes of homologous and heterologous bacteriophages. Genomes of bacteriophages from B. pertussis 134, 41405 and B. bronchiseptica 214 were studied. Heteroduplex and restriction analyses revealed a heterogeneity of bacteriophage populations, and their DNAs were found to differ in size and position of inserts. As shown by blot hybridization, the bacteriophage genome is not inserted into the chromosome of the lysogenic cell but apparently exists as an autonomous plasmid replicon. It has been established that during conversion only a part of the phage genome is inserted into the chromosome of the recipient cell.
Assuntos
Bacteriófagos/genética , DNA Viral/ultraestrutura , Lisogenia , Autorradiografia , Bacteriófagos/fisiologia , Bacteriófagos/ultraestrutura , Southern Blotting , Bordetella , Bordetella pertussis , DNA Viral/genética , Desoxirribonucleases de Sítio Específico do Tipo II , Microscopia Eletrônica , Hibridização de Ácido NucleicoRESUMO
A molecular probe for the PT-operon of B. pertussis hybridized with 4.7 Kb EcoRI-fragments of chromosomal DNAs of B. pertussis strain 475 phase I, phase IV, B. parapertussis strains 504 and 17903, B. bronchiseptica strain 214, B. parapertussis strain 17903-convertant of B. pertussis phage 134 but not with phage 134 DNA under stringent conditions of DNA-DNA hybridization. This fact indicates the presence of PT-genes in all Bordetella species. Since there is no production of PT in B. parapertussis and B. bronchiseptica, a presence of regulatory mutations in the PT-operon or absence of the functionally active vir-gene product in these species is suggested.