Journal of Pure and Applied MicrobiologyVol. 8 No. May 2014 Special Edition

Inhibition of Quorum Sensing-mediated Bioluminescence in Vibrio harveyi by a Recombinant AHL-lactonase from Bacillus cereus

Nguyen Thi Ngoc Tinh*, Nguyen Viet Dung, Van Thi Thuy and Nguyen Thao Suong

Research Institute for Aquaculture No. 2, Hochiminh City, Vietnam.

Received on 12 April 2014 and accepted on 09 May 2014



Quorum sensing is a cell-to-cell communication process in bacterial kingdom, in which the expression of genetic information is controlled via the production and detection of ?signal molecules? in a population density-dependent manner. Quorum sensing system has been discovered and shown to control virulence factors in several Gram-negative bacterial pathogens in aquaculture, including Vibrio harveyi, a harmful bacterium in shrimp. It has been shown that the ability to inactivate AHL signal molecules may be useful in controlling the AHL-mediated virulence in many Gram-negative pathogenic bacteria. AHL-lactonase, one of the three AHL-disrupting enzyme classes, attracts significant interest of researchers due to its high substrate specificity toward AHL signals. In this study, a recombinant and purified AHL-lactonase (AiiAN26.2 protein) was verified for its ability to inhibit bioluminescence of V. harveyi cultures. AiiAN26.2 protein at a concentration of 15 ?g ml-1 could significantly attenuate the luminescence intensity of V. harveyi cultures over a 6-hour period. The findings of the study are important for future research as it was proven that recombinant AHL-lactonase can be used to control infectious diseases in aquaculture which are related to the AHL-mediated quorum sensing system.

Keywords : AHL-lactonase; AHL-mediated quorum sensing; bioluminescence; Vibrio harveyi.