Functional analysis of AI-2/LuxS from bacteria in Chinese fermented meat after high nitrate concentration shock

Abstract

LuxS-mediated quorum-sensing mechanism, which was based on the production of universal signal molecule called autoinducer-2 (AI-2), regulates important physiological traits and a variety of adaptive processes in different bacteria. But little was known about AI-2/LuxS of lactobacillus bacteria from fermented meat. Bacterial strains of the species Lactobacillus sakei; Lactobacillus sp. and Lactobacillus plantarum, all isolated from Chinese fermented meat, were found to possess AI-2 activity and LuxS every 3 h during 36 h. In contrast, all the strains were found to have AI-2 activity and the full-length cDNA sequences of LuxS gene were obtained. The qRT-PCR analysis indicated that all LuxS gene showed strongly up-regulated after high nitrate concentration shock. The changes of LuxS during 36 h were shown in wavy curve rather than parabolic curve different from the lasted reports. The fact that AI-2 activity and LuxS gene are produced by bacterial strains found in the Chinese fermented meat. And also increased by meat-relevant stress conditions, indicated that AI-2/LuxS signaling might be important in regulation of microbial succession during ripened of Chinese fermented meat.