TY - JOUR
T1 - Virulence of an exotoxin A-deficient strain of Pseudomonas aeruginosa toward the silkworm, Bombyx mori
AU - Chieda, Yuuka
AU - Iiyama, Kazuhiro
AU - Lee, Jae Man
AU - Kusakabe, Takahiro
AU - Yasunaga-Aoki, Chisa
AU - Shimizu, Susumu
N1 - Funding Information:
We thank Dr. Mathias Keller for supplying pK18mobsacB and E. coli strain S17-1, and Dr. Marie-Héléne Blondelet-Rouault for pHP45Ωaac. We also thank Dr. Michael E. Kovach for pBBR1MCS2. Finally, we thank Dr. Junichi Kato for providing P. aeruginosa strain PAO1. The cost of publication was supported in part by a Research Grant for Young Investigators from the Faculty of Agriculture, Kyushu University .
PY - 2011/12
Y1 - 2011/12
N2 - We studied the contribution of exotoxin A to the virulence of Pseudomonas aeruginosa against the silkworm, Bombyx mori. First, an exotoxin A-deficient mutant strain (PAO1toxA) was created, and its virulence compared with that of the parental PAO1 strain. In a short-term mortality assay, the mutant harboring pBBR1MCS2 did not kill B. mori until 120 h after inoculation and complementation of the corresponding gene in trans restored the strain's virulence. Next, to ascertain whether or not it lost all virulence, PAO1toxA (pBBR1MCS2, pGFP) was used in a long-term mortality assay. B. mori inoculated with the mutant strain did not die until early in the 5th instar (240 h after inoculation). However, 50% of the inoculated B. mori died late in the 5th instar or in the early pupal stage (408 h after inoculation). All had died by the pupal stage (600 h after inoculation). The mutant strain was isolated from dead larvae and cocoons. The bacterial population of PAO1toxA in hemolymph reached 4.77 × 10 7 cfu/ml. These results indicated that exotoxin A acts as a virulence factor in B. mori and that other virulence factor(s) are involved during the late stages of infection.
AB - We studied the contribution of exotoxin A to the virulence of Pseudomonas aeruginosa against the silkworm, Bombyx mori. First, an exotoxin A-deficient mutant strain (PAO1toxA) was created, and its virulence compared with that of the parental PAO1 strain. In a short-term mortality assay, the mutant harboring pBBR1MCS2 did not kill B. mori until 120 h after inoculation and complementation of the corresponding gene in trans restored the strain's virulence. Next, to ascertain whether or not it lost all virulence, PAO1toxA (pBBR1MCS2, pGFP) was used in a long-term mortality assay. B. mori inoculated with the mutant strain did not die until early in the 5th instar (240 h after inoculation). However, 50% of the inoculated B. mori died late in the 5th instar or in the early pupal stage (408 h after inoculation). All had died by the pupal stage (600 h after inoculation). The mutant strain was isolated from dead larvae and cocoons. The bacterial population of PAO1toxA in hemolymph reached 4.77 × 10 7 cfu/ml. These results indicated that exotoxin A acts as a virulence factor in B. mori and that other virulence factor(s) are involved during the late stages of infection.
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U2 - 10.1016/j.micpath.2011.09.002
DO - 10.1016/j.micpath.2011.09.002
M3 - Article
C2 - 21945328
AN - SCOPUS:80054841862
SN - 0882-4010
VL - 51
SP - 407
EP - 414
JO - Microbial Pathogenesis
JF - Microbial Pathogenesis
IS - 6
ER -
