N-acyl Homoserine Lactone-Producing or -Degrading Bacteria Isolated from the Intestinal Microbial Flora of Ayu Fish {Plecoglossus altivelis)

Abstract

A number of gram-negative fish pathogens have a quorum-sensing system. These bacteria produce N-acyl-L-homoserine lactone (AHL) as a quorum-sensing signal molecule. We isolated AHL-producing and degrading bacteria from the intestinal microbial flora of Ayu fish {Plecoglossus altivelis). AHL-producing and degrading isolates were identified as members of the genus Aeromonas and Shewanella, respectively. Aeromonas sp. Strain MIB010 produced at least three kinds of AHLs and it was predicted that the production of extracellular protease in strain MIB010 was regulated through quorum sensing. Shewanella sp. Strain MIB015 showed obvious AHL-degrading activity and interrupted the AHL-mediated production of protease by the Aeromonas sp. Intestinal Shewanella strains might be useful as probiotic bacteria effective in the prevention of bacterial infectious diseases controlled by quorum sensing. © 2005, Japanese Society of Microbial Ecology & The Japanese Society of Soil Microbiology. All rights reserved.