AUTHOR=Yang Yang , Zhou Mingxu , Hardwidge Philip R. , Cui Hengmi , Zhu Guoqiang 

TITLE=Isolation and Characterization of N-acyl Homoserine Lactone-Producing Bacteria From Cattle Rumen and Swine Intestines

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=8

YEAR=2018

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2018.00155

DOI=10.3389/fcimb.2018.00155

ISSN=2235-2988

ABSTRACT=<p>Quorum sensing systems regulate gene expression in response to bacterial population density. Acyl-homoserine lactones are a class of quorum sensing molecules found in cattle rumen that are thought to regulate the gene expression of enterohemorrhagic <italic>Escherichia coli</italic> and thus help this pathogen survive in animal gastrointestinal tracts. However, the specific bacteria that produce these signaling molecules in bovine and porcine gastrointestinal tracts are unknown. Here we developed methods to concentrate gastrointestinal fluids and screen the bacteria that produce acyl-homoserine lactones. We isolated a <italic>Pseudomonas aeruginosa</italic> strain YZ1 from cattle rumen, and an <italic>Aeromonas hydrophila</italic> strain YZ2 from pig intestine. Mass spectrometry analysis of culture supernatants indicated at least three specific classes of acyl-homoserine lactones produced by YZ1, and a C4-acyl-homoserine lactone produced by YZ2. Transformation of <italic>E. coli</italic> with <italic>P. aeruginosa</italic> or <italic>A. hydrophila luxI</italic> homologs,which can produce short- or long-chain acyl-homoserine lactones conferred upon <italic>E. coli</italic> the ability to synthesize acyl-homoserine lactones and affected gene expression, motility, and acid tolerance of <italic>E. coli</italic>. This is the first study reporting the isolation and characterization of acyl-homoserine lactone synthase-positive bacteria from cattle rumen and swine intestines.</p>