title: Long-chain acyl-homoserine lactone quorum-sensing regulation of Rhodobacter capsulatus gene transfer agent production.
abstract: Many proteobacteria use acyl-homoserine lactones as quorum-sensing signals. Traditionally, biological detection systems have been used to identify bacteria that produce acyl-homoserine lactones, although the specificities of these detection systems can limit discovery. We used a sensitive approach that did not require a bioassay to detect production of long-acyl-chain homoserine lactone production by Rhodobacter capsulatus and Paracoccus denitrificans. These long-chain acyl-homoserine lactones are not readily detected by standard bioassays. The most abundant acyl-homoserine lactone was N-hexadecanoyl-homoserine lactone. The long-chain acyl-homoserine lactones were concentrated in cells but were also found in the culture fluid. An R. capsulatus gene responsible for long-chain acyl-homoserine lactone synthesis was identified. A mutation in this gene, which we named gtaI, resulted in decreased production of the R. capsulatus gene transfer agent, and gene transfer agent production was restored by exogenous addition of N-hexadecanoyl-homoserine lactone. Thus, long-chain acyl-homoserine lactones serve as quorum-sensing signals to enhance genetic exchange in R. capsulatus.
authors.affiliation: Department of Microbiology and W. M. Keck Foundation Microbial Communities & Cell Signaling Laboratory, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Schaefer
authors.forename: Terumi A
authors.initials: TA
authors.lastname: Taylor
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Beatty
authors.forename: E P
authors.initials: EP
authors.lastname: Greenberg
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D022761:Gene Transfer, Horizontal; D008025:Ligases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010231:Paracoccus denitrificans / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D016354:Rhodobacter capsulatus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D014161:Transduction, Genetic
chemical_list: D001426:Bacterial Proteins; C088386:homoserine lactone; D008025:Ligases; C449816:N-acylhomoserine lactone synthase; D015107:4-Butyrolactone