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Add To Calendar 28/04/2016 08:50:0028/04/2016 09:10:00Africa/JohannesburgAsian-Pacific Aquaculture 2016ISOLATION OF NATURAL pirA-/pirB+ Vibrio parahaemolyticus STRAIN AND THE REQUIREMENT OF BINARY PIR TOXINS IN CAUSING ACUTE HEPATOPANCREATIC NECROSIS DISEASE PATHOGENESIS IN SHRIMP Diamond 1The World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY

ISOLATION OF NATURAL pirA-/pirB+ Vibrio parahaemolyticus STRAIN AND THE REQUIREMENT OF BINARY PIR TOXINS IN CAUSING ACUTE HEPATOPANCREATIC NECROSIS DISEASE PATHOGENESIS IN SHRIMP

Walaiporn Charoensapsri*, Kornsunee Phiwsaiya, Suwimon Thaengphu, Ha T. Dong, Pakkakul Sangsuriya, Giang T.T. Nguyen, Piti Amparyup, Suparat Taengchaiyaphum, Kallaya Sritunyalucksana, Timothy W. Flegel, and Saengchan Senapin
 
Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Rama VI Rd., Bangkok, 10400, Thailand and National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, 12120, Thailand
walaiporn.cha@biotec.or.th

Acute hepatopancreatic necrosis disease (AHPND) in shrimp is an emerging disease caused by the virulence strains of the bacterium Vibrio parahaemolyticus. The histological characteristic of AHPND pathogenesis is typically defined by sloughing of the hepatopancreas tubule epithelial cells into the lumen in which is caused by the binary toxin Photorhabdus insect-related (Pir) encoded by pirA and pirB genes resided in the virulence plasmid of the bacterial V. parahaemolyticus cells. In the present study, a natural V. parahaemolyticus lacking of pirA (pirA-/pirB+) was identified among pirA+/pirB+ isolates obtained from Vietnam. Genetic variation of the virulence plasmids was initially observed among the isolates using nested PCR with primers targeting to the binary Pir toxin genes and the absence of pirA gene in the pirA-/pirB+ isolate was subsequently confirmed by a previously established duplex PCR detection. Sequence analysis revealed the absence of pirA gene in the pirA-/pirB+ isolate was due to a 1053 bp-fragment containing a putative transposase gene insertion. The requirement of both pirA and pirB encoding binary toxins in causing AHPND pathology in shrimp was subsequently examined by performing virulence assay using the immersion method followed by histological examination. The results confirmed that V. parahaemolyticus strains harboring both pirA and pirB caused typical deadly APHND pathology while pirA-/pirB+ strain was less pathogenic and caused collapse epithelium instead of cell sloughing in the shrimp hepatopancreatic tubules.




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