title: Inactivation of pyocyanin synthesis genes has no effect on the virulence of Pseudomonas aeruginosa PAO1 toward the silkworm, Bombyx mori.
abstract: The contribution of pyocyanin to the virulence of Pseudomonas aeruginosa against the silkworm Bombyx mori was studied. First, purified pyocyanin was injected into the hemocoel of B. mori. Acute toxicity was observed only when a high dose of pyocyanin was injected. The lethal dose 50% value of pyocyanin was found to be 9.52 microg per larva. Next, mutant strains of phzM and phzS, which encode putative phenazine-specific methytransferase and flavin-containing monooxygenase, respectively, were created, and their virulence was compared with that of the PAO1 parent strain. Although the ability to produce pyocyanin was completely lost in the phz-mutant strains, they maintained the same level of virulence as the PAO1 parent strain. In addition, the complementation of the corresponding gene in trans in the mutant strains did not have any effect on the virulence of those mutant strains. These results indicated that pyocyanin does not act as a virulence factor in B. mori after invasion, which was different from the results obtained in other Lepidopteran host models.
authors.affiliation: Laboratory of Insect Pathology and Microbial Control, Institute of Biological Control, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan.
authors.forename: Yuuka
authors.initials: Y
authors.lastname: Chieda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Iiyama
authors.forename: Jae Man
authors.initials: JM
authors.lastname: Lee
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusakabe
authors.forename: Chisa
authors.initials: C
authors.lastname: Yasunaga-Aoki
authors.forename: Susumu
authors.initials: S
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D012831:Bombyx / Q000382:microbiology*; D004195:Disease Models, Animal; D054884:Host-Pathogen Interactions / Q000235:genetics; D007814:Larva; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009026:Mortality; D016296:Mutagenesis; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D011710:Pyocyanine / Q000096:biosynthesis; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D011710:Pyocyanine; D006899:Mixed Function Oxygenases; C439053:PhzS protein, Pseudomonas aeruginosa; D008780:Methyltransferases; C439052:PhzM protein, Pseudomonas aeruginosa