title: A marine Mesorhizobium sp. produces structurally novel long-chain N-acyl-L-homoserine lactones.
abstract: Our study focused on a Mesorhizobium sp. that is phylogenetically affiliated by 16S rRNA gene sequence to other marine and saline bacteria of this genus. Liquid chromatography-mass spectrometry investigations of the extract obtained from solid-phase extraction of cultures of this bacterium indicated the presence of several N-acyl homoserine lactones (AHLs), with chain lengths of C(10) to C(16). Chromatographic separation of the active bacterial extract yielded extraordinarily large amounts of two unprecedented acylated homoserine lactones, 5-cis-3-oxo-C(12)-homoserine lactone (5-cis-3-oxo-C(12)-HSL) (compound 1) and 5-cis-C(12)-HSL (compound 2). Quorum-sensing activity of compounds 1 and 2 was shown in two different biosensor systems [Escherichia coli MT102(pSB403) and Pseudomonas putida F117(pKR-C12)]. Furthermore, it was shown that both compounds can restore protease and pyoverdin production of an AHL-deficient Pseudomonas aeruginosa PAO1 lasI rhlI double mutant, suggesting that these signal molecules maybe used for intergenus signaling. In conclusion, these data indicate that the quorum-sensing activity of compounds 1 and 2 is modulated by the chain length and functional groups of the acyl moiety. Additionally, compound 1 showed antibacterial and cytotoxic activities.
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, D-53115 Bonn, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Krick
authors.forename: Stefan
authors.initials: S
authors.lastname: Kehraus
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Kathrin
authors.initials: K
authors.lastname: Riedel
authors.forename: Heidrun
authors.initials: H
authors.lastname: Anke
authors.forename: Ines
authors.initials: I
authors.lastname: Kaesler
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Graeber
authors.forename: Ulrich
authors.initials: U
authors.lastname: Szewzyk
authors.forename: Gabriele M
authors.initials: GM
authors.lastname: König
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001407:Bacillus / Q000187:drug effects; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002853:Chromatography, Liquid; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects; D017353:Gene Deletion; D020459:Genes, rRNA; D008025:Ligases / Q000235:genetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009664:Norway; D010802:Phylogeny; D011161:Porifera / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D016958:Pseudomonas putida / Q000187:drug effects; D053038:Quorum Sensing / Q000187:drug effects; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; C081237:LasI protein, Pseudomonas aeruginosa; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D014157:Transcription Factors; D008025:Ligases; C096955:RHLI protein, Pseudomonas aeruginosa