Zhang, BaoZhuang, XiyiGuo, LiyunMcLean, Robert J. C.Chu, Weihua2019-09-062019-09-062019-08Zhang, B., Zhuang, X., Guo, L., McLean, R. J. C., & Chu, W. (2019). Recombinant N-acyl homoserine lactone-Lactonase AiiAQSI-1 Attenuates Aeromonas hydrophila Virulence Factors, Biofilm Formation and Reduces Mortality in Crucian Carp. Marine Drugs, 17(9): 499.https://hdl.handle.net/10877/8603Quorum quenching (QQ) is a promising alternative infection-control strategy to antibiotics that controls quorum-regulated virulence without killing the pathogens. Aeromonas hydrophila is an opportunistic gram-negative pathogen living in freshwater and marine environments. A. hydrophila possesses an N-acyl homoserine lactone (AHL)-based quorum-sensing (QS) system that regulates virulence, so quorum signal-inactivation (i.e., QQ) may represent a new way to combat A. hydrophila infection. In this study, an AHL lactonase gene, aiiA was cloned from Bacillus sp. strain QSI-1 and expressed in Escherichia coli strain BL21(DE3). The A. hydrophila hexanoyl homoserine lactone (C6-HSL) QS signal molecule was degraded by Aii AQSI-1, which resulted in a decrease of bacterial swimming motility, reduction of extracellular protease and hemolysin virulence factors, and inhibited the biofilm formation of A. hydrophila YJ-1 in a microtiter assay. In cell culture studies, Aii AQSI-1 decreased the ability of A. hydrophila adherence to and internalization by Epithelioma papulosum cyprini (EPC) cells. During in vivo studies, oral administration of AiiA QSI-1 via feed supplementation attenuated A. hydrophila infection in Crucian Carp. Results from this work indicate that feed supplementation with Aii AQSI-1 protein has potential to control A. hydrophila aquaculture disease via QQ.Text12 pages1 file (.pdf)encrucian CarpN-acyl homoserine lactone lactonasebiofilmvirulence factorsaeromonas hydrophilaBiologyArticle© 2019 The Authors.https://doi.org/10.3390/md17090499This work is licensed under a Creative Commons Attribution 4.0 International License.