title: Production of acylated homoserine lactones by Aeromonas and Pseudomonas strains isolated from municipal activated sludge.
abstract: Up to now, the production and role of N-acyl homoserine lactones (AHLs) in activated sludge have been poorly understood. In this study, cross-feeding assays with the reporter strains Agrobacterium tumefaciens NTL4 and Chromobacterium violaceum CV026 were used to investigate AHL signal production by municipal activated sludge samples. AHL signal production was consistently detected from municipal activated sludge when different samples were incubated on nutrient media. From one municipal activated sludge sample, 10 strains producing AHL-like auto inducers were isolated by an overlay technique. 16S rDNA-based phylogenetic analysis showed that eight of the isolates belonged to Aeromonas spp. and two to Pseudomonas spp. Box-PCR indicated that six of these Aeromonas isolates were different strains and the two Pseudomonas strains were identical. The production of AHL or AHL-like compounds by these strains was confirmed by thin layer chromatography and biosensor overlays. The six different Aeromonas strains were found to produce the same set of AHLs, including N-hexanoyl-L-homoserine lactone. These results may indicate the possible presence of AHLs in municipal activated sludge. The potential roles of AHL in this eco system are briefly discussed.
authors.affiliation: Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Fernando
authors.initials: F
authors.lastname: Morgan-Sagastume
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Sofie
authors.initials: S
authors.lastname: Dobbelaere
authors.forename: Tom
authors.initials: T
authors.lastname: Defoirdt
authors.forename: Willy
authors.initials: W
authors.lastname: Verstraete
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry; D000333:Aeromonas / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D016960:Agrobacterium tumefaciens / Q000254:growth & development; D015373:Bacterial Typing Techniques / Q000379:methods; D002855:Chromatography, Thin Layer; D002861:Chromobacterium / Q000254:growth & development; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D011549:Pseudomonas / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C088386:homoserine lactone; D015107:4-Butyrolactone