RESUMO
PS17 is a bacteriophage of Pseudomonas aeruginosa that is serologically cross-reactive with phage tail-like bacteriocins called R-type pyocins. In addition to having immunological cross-reactivity, certain genes are functionally complementable between PS17 and R-type pyocins. To compare the genetic structures of PS17 and R-type pyocins, a physical map of PS17 genes was constructed by cloning phage DNA fragments on RSF1010-derived vector plasmids. The head and tail gene clusters were tandemly arrayed and together occupied about half of the 41-kilobase-pair PS17 chromosome. With use of these phage clones, the following results were obtained with respect to the genetic relationship between PS17 and R-type pyocins: (i) serological cross-reaction between PS17 and pyocin occurred for the major sheath protein and two components of the fiber, (ii) a certain pyocin mutation was complemented by cloned phage fragments, and (iii) the phage DNA fragment carrying sheath and core tube genes was shown to hybridize to the DNA fragment carrying the pyocin R2 genes.
Assuntos
Bacteriocinas/genética , Bacteriófagos/genética , Pseudomonas aeruginosa/genética , Piocinas/genética , Western Blotting , Clonagem Molecular , DNA Viral/genética , Genes Bacterianos , Genes Virais , Teste de Complementação Genética , Peso Molecular , Hibridização de Ácido Nucleico , Piocinas/imunologia , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Proteínas Virais/genéticaRESUMO
The genetic determinant for pyocin AP41 , a bacteriocin produced by Pseudomonas aeruginosa PAF, was transferred to P. aeruginosa PAO and analyzed. By conjugation experiments, the pyocin determinant was found to be located on the chromosome, being closely linked to argG at about 45 min on the genetic map. Cloning of the pyocin AP41 gene into the plasmid R68.45 was attempted in vivo by taking advantage of its linkage at argG. R' argG+ plasmids were isolated by interspecific conjugation between P. aeruginosa and Escherichia coli recA argG strains. Some of the R' argG+ plasmids did contain the pyocin AP41 determinant. Genetic and physical analyses of these R' plasmids indicated that the pyocin AP41 determinant was located within a 2.9-kilobase extra segment found at a certain position of the chromosome of various pyocin AP41 producer strains.
Assuntos
Bacteriocinas/genética , Cromossomos Bacterianos , Genes Bacterianos , Pseudomonas aeruginosa/genética , Piocinas/genética , Mapeamento Cromossômico , Clonagem Molecular , Conjugação Genética , DNA Bacteriano/genética , Ligação Genética , Marcadores Genéticos , Mitomicina , Mitomicinas/farmacologia , Hibridização de Ácido Nucleico , Plasmídeos , Pseudomonas aeruginosa/metabolismo , Piocinas/biossíntese , RNA Bacteriano/genéticaRESUMO
Previous results indicate that a group of bacteriocins in Pseudomonas aeruginosa, named R-type pyocins, have a structure resembling bacteriophage tails and share some serological homology with certain bacteriophages. This paper presents genetic evidence which strongly suggests that components of pyocin R2, an R-type pyocin of P. aeruginosa PAO, and tail components of bacteriophage PS17 are interchangeable. Complementation tests with pyocin R2-deficient mutants of PAO and ts mutants of PS17 revealed that various phenotypic interactions occur between the pyocin and bacteriophage in PAO cells lysogenized or infected with PS17. (i) Certain pyocin R2-deficient mutations were phenotypically suppressed in cells carrying PS17 prophage. (ii) A temperature-sensitive mutant of PS17, tsQ31, was phenotypically suppressed in PAO cells treated with mitomycin C. (iii) Phenotypically mixed phages with receptor and serological specificities of pyocin R2 were formed in PS17 lysogens of certain pyocin R2-deficient mutants.
Assuntos
Bacteriocinas/genética , Bacteriófagos/genética , Pseudomonas aeruginosa/genética , Piocinas/genética , Genes Bacterianos , Genes Virais , Teste de Complementação Genética , Genótipo , Mutação , Fenótipo , Especificidade da EspécieRESUMO
Thirty-seven mutants defective in pyocin R2 production in the P. aeruginosa PAO strain were subjected to fine mapping of pyocin R2 genes by transduction with phage F116L. Sixteen complementation groups (designated prtA through prtP) involved in pyocin R2 production were tentatively identified by complementation tests using phage F116L. Their linkages to trpC and trpE markers and fine mapping by three point crosses demonstrated that most of the mutations (prtA through prtN) were located in between trpC and trpE, and that the prtP mutation was localized outside this major prt cluster but in the proximity of the rifA and strA region.
Assuntos
Bacteriocinas/genética , Genes Bacterianos , Pseudomonas aeruginosa/genética , Piocinas/genética , Mapeamento Cromossômico , Cromossomos Bacterianos , Teste de Complementação Genética , Ligação Genética , Mutação , Pseudomonas aeruginosa/ultraestruturaRESUMO
The chromosome segment which contains the genes responsible for production of pyocin R2 in P. aeruginosa PAO was defined physically using R-prime plasmids constructed in vivo from R68.45. The previous conclusion from genetic mapping that the cluster of pyocin R2 genes is located in between trpC and trpE genes was confirmed by deletion mapping of various R prime plasmids bearing the trpC gene. The pyocin R2 gene cluster was further localized on two contiguous HindIII fragments of 16 kb and 8.0 kb. PML14 strain, in which R-type pyocin genes were completely deleted, had only one 11 kb HindIII fragment instead. Heteroduplexes between this 11 kb fragment with the two HindIII fragments of PAO revealed that the cluster of pyocin R2 genes was an insertion 13 kb long.
