title: Unusual long-chain N-acyl homoserine lactone production by and presence of quorum quenching activity in bacterial isolates from diseased tilapia fish.
abstract: Growth-dependent cell-cell communication termed quorum sensing is a key regulatory system in bacteria for controlling gene expression including virulence factors. In this study five potential bacterial pathogens including Bacillus sp. W2.2, Klebsiella sp. W4.2, Pseudomonas sp. W3 and W3.1 and Serratia sp. W2.3 were isolated from diseased Tilapia fish in Malaysia, supplied by the leading global fish supplier. Proteolytic activity assays confirmed that with the exception of Klebsiella sp. W4.2, all isolates showed distinct proteolytic activity. Furthermore Bacillus sp. W2.2 and Pseudomonas sp. strains W3 and W3.1 also displayed haemolytic activity. By using high resolution liquid chromatography mass spectrometry, we revealed the presence of unusually long-chain N-(3-oxohexadecanoyl)-homoserine lactone (3-oxo-C16-HSL) from Pseudomonas sp. W3.1 and N-dodecanoyl-homoserine lactone (C12-HSL) from Serratia sp. W2.3, respectively. Interestingly, Pseudomonas sp. W3.1 also produced a wide range of Pseudomonas quinolone signalling (PQS) molecules. Pseudomonas sp. W3 did not show any quorum sensing properties but possessed quorum quenching activity that inactivated AHLs. This study is the first documentation that shows unusual long-chain AHLs production in Serratia sp. and Pseudomonas sp. isolated from diseased fish and the latter also produce a wide range of PQS molecules.
authors.affiliation: School of Molecular Medical Sciences, Centre for Biomolecular Science, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Chien-Yi
authors.initials: CY
authors.lastname: Chang
authors.forename: Chong-Lek
authors.initials: CL
authors.lastname: Koh
authors.forename: Choon-Kook
authors.initials: CK
authors.lastname: Sam
authors.forename: Xin-Yue
authors.initials: XY
authors.lastname: Chan
authors.forename: Wai Fong
authors.initials: WF
authors.lastname: Yin
authors.forename: Kok Gan
authors.initials: KG
authors.lastname: Chan
mesh_terms: D054742:Acyl-Butyrolactones / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001419:Bacteria / Q000166:cytology* / Q000302:isolation & purification* / Q000378:metabolism / Q000472:pathogenicity; D001483:Base Sequence; D015374:Biosensing Techniques; D002855:Chromatography, Thin Layer; D004275:DNA, Ribosomal / Q000235:genetics; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology; D005393:Fish Diseases / Q000382:microbiology*; D008296:Malaysia; D013058:Mass Spectrometry; D010641:Phenotype; D010802:Phylogeny; D053038:Quorum Sensing; D017210:Tilapia / Q000382:microbiology*; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D054742:Acyl-Butyrolactones; D004275:DNA, Ribosomal; D037521:Virulence Factors