title: The signalling molecule Autoinducer-2 is not internalised in Campylobacter jejuni.
abstract: Bacteria recognise and constantly adjust to changing situations by sensing environmental and self-produced signals. Autoinducer-2 (AI-2) is a signal molecule, found in many bacterial species and thus proposed to enable interspecies com- munication. Two classes of AI-2 receptors have been identified so far. One class of AI-2 receptors sense AI-2 by a two component signalling system.The other class, the LsrB family, internalises and phosphorylates AI-2. Campylobacter (C.) jejuni is known to produce AI-2, but no AI-2 receptor in C. jejuni has been found yet.Therefore, all research on AI-2 dependent phenotypes has been conducted with AI-2 synthase (luxS) mutants. This mutation also leads to a disruption of the activated methyl cycle. Most studies lack sufficient complementation result- ing in not knowing whether phenotypes of luxS mutants depend on disrupted metabolism or lack of AI-2. All this contributes to an intensive discussion, about the exact role of AI-2 in C. jejuni. Our previous study showed altering phenotypes (growth and motility) of the Cjejuni NCTC 11168ΔluxS mutant in contrast to wild type, which could be complemented with synthetic AI-2. To assess how AI-2 induces the altering phenotypes during complementation assays, we performed an AI-2 uptake assay. Our data show, that AI-2 is not internalised by C. jejuni.These data suggest, that yet unknown AI-2 receptors are present on the cell surface of C. jejuni. Therefore further search of AI-2 receptors in C. jejuni should focus on two component signalling systems and not on transporter systems.
authors: Linda
authors: L
authors: Adler
authors: Thomas
authors: T
authors: Alter
authors: Soroush
authors: S
authors: Sharbati
authors: Greta
authors: G
authors: Gölz
mesh_terms: D016123:Campylobacter jejuni / Q000378:metabolism*; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D007783:Lactones / Q000378:metabolism*; D008958:Models, Molecular; D053038:Quorum Sensing; D015398:Signal Transduction
chemical_list: D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine