title: Role of LuxIR Homologue AnoIR in Acinetobacter nosocomialis and the Effect of Virstatin on the Expression of anoR Gene.
abstract: Quorum sensing is a process of cell-to-cell communication in which bacteria produce autoinducers as signaling molecules to sense cell density and coordinate gene expression. In the present study, a LuxI-type synthase, AnoI, and a LuxR-type regulator, AnoR, were identified in Acinetobacter nosocomialis, an important nosocomial pathogen, by sequence analysis of the bacterial genome. We found that N-(3-hydroxy-dodecanoyl)-L-homoserine lactone (OH-dDHL) is a quorum-sensing signal in A. nosocomialis. The anoI gene deletion was responsible for the impairment in the production of OH-dDHL. The expression of anoI was almost abolished in the anoR mutant. These results indicate that AnoI is essential for the production of OH-dDHL in A. nosocomialis, and its expression is positively regulated by AnoR. Moreover, the anoR mutant exhibited deficiency in biofilm formation. In particular, motility of the anoR mutant was consistently and significantly abolished compared with that of the wild type. The deficiency in the biofilm formation and motility of the anoR mutant was significantly restored by a functional anoR , indicating that AnoR plays important roles in the biofilm formation and motility. Furthermore, the present study showed that virstatin exerts its effects on the reduction of biofilm formation and motility by inhibiting the expression of anoR . Consequently, the combined results suggest that AnoIR is a quorum-sensing system that plays important roles in the biofilm formation and motility of A. nosocomialis, and virstatin is an inhibitor of the expression of anoR.
authors.affiliation: Department of Nanobiomedical Science, Dankook University, Cheonan 330-714, Republic of Korea.
authors.forename: Man Hwan
authors.initials: MH
authors.lastname: Oh
authors.affiliation: Department of Microbiology and Research Institute for Medical Sciences, College of Medicine, Chungnam National University, Daejeon 301-747, Republic of Korea.
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Choi
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D002087:Butyrates / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D016680:Genome, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D008124:Locomotion; D008969:Molecular Sequence Data; D053644:Naphthalimides / Q000378:metabolism*; D053038:Quorum Sensing; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D002087:Butyrates; D004269:DNA, Bacterial; D007783:Lactones; D053644:Naphthalimides; C505381:virstatin; C085113:Pseudomonas aeruginosa autoinducer; D006714:Homoserine
keywords: Acinetobacter nosocomialis; AnoIR; biofilm, motility; quorum sensing; virstatin