title: Are there acyl-homoserine lactones within mammalian intestines?
abstract: Many Proteobacteria are capable of quorum sensing using N-acyl-homoserine lactone (acyl-HSL) signaling molecules that are synthesized by LuxI or LuxM homologs and detected by transcription factors of the LuxR family. Most quorum-sensing species have at least one LuxR and one LuxI homolog. However, members of the Escherichia, Salmonella, Klebsiella, and Enterobacter genera possess only a single LuxR homolog, SdiA, and no acyl-HSL synthase. The most obvious hypothesis is that these organisms are eavesdropping on acyl-HSL production within the complex microbial communities of the mammalian intestinal tract. However, there is currently no evidence of acyl-HSLs being produced within normal intestinal communities. A few intestinal pathogens, including Yersinia enterocolitica, do produce acyl-HSLs, and Salmonella can detect them during infection. Therefore, a more refined hypothesis is that SdiA orthologs are used for eavesdropping on other quorum-sensing pathogens in the host. However, the lack of acyl-HSL signaling among the normal intestinal residents is a surprising finding given the complexity of intestinal communities. In this review, we examine the evidence for and against the possibility of acyl-HSL signaling molecules in the mammalian intestine and discuss the possibility that related signaling molecules might be present and awaiting discovery.
authors.affiliation: Department of Microbiology, The Ohio State University, Columbus, OH, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Swearingen
authors.forename: Anice
authors.initials: A
authors.lastname: Sabag-Daigle
authors.forename: Brian M M
authors.initials: BM
authors.lastname: Ahmer
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism*; D000818:Animals; D004755:Enterobacteriaceae / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D015398:Signal Transduction
chemical_list: D054742:Acyl-Butyrolactones