Identification of cistrons involved in conjugal transfer of narrow-host-range R plasmid R91-5 of Pseudomonas aeruginosa.
The development of a transductional method for complementation tests between transfer-deficient mutants of the narrow-host-range R plasmic R91-5 of Pseudomonas aeruginosa has allowed the indentification of cistrons involved in the conjugal transfer of this plasmid. Complementation tests performed between transfer-deficient mutants characterized phenotypically with respect to sensitivity to donor-specific phage, ability to inhibit the replication of phage G101, and expression of entry-exclusion has identified a minimum of 10 transfer cistrons. Although most mutagen-induced mutants were relatively heterogeneous and appeared to be affected in a single cistron only, a high proportion of mutants isolated after selection for donor-specific phage resistance had deletions but always included tra Y. Mutants selected directly on the basis of transfer deficiency which also became donor-specific phage resistant fell into all 10 cistrons, suggesting that many R91-5 transfer cistrons are concerned with the synthesis of sex pili and other surface structures necessary for conjugal transfer. Conversely, most retaining donor-specific phage sensitivity belonged to one cistron, whereas transfer-deficient mutants which had also lost the ability to inhibit the replication of phage G101 comprised four cistrons.
D001435:Bacteriophages / Q000254:growth & development; D003227:Conjugation, Genetic; D005796:Genes; D005816:Genetic Complementation Test; D008769:Methylnitronitrosoguanidine; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D011815:R Factors; D014161:Transduction, Genetic; D014779:Virus Replication
D008769:Methylnitronitrosoguanidine