title: Modulation of violacein production and phenotypes associated with biofilm by exogenous quorum sensing N-acylhomoserine lactones in the marine bacterium Pseudoalteromonas ulvae TC14.
abstract: Various phenotypes ranging from biofilm formation to pigment production have been shown to be regulated by quorum sensing (QS) in many bacteria. However, studies of the regulation of pigments produced by marine bacteria in saline conditions and of biofilm-associated phenotypes are scarcer. This study focuses on the demonstration of the existence of a QS communication system involving N-acylhomoserine lactones (AHLs) in the Mediterranean Sea strain Pseudoalteromonas ulvae TC14. We have investigated whether TC14 produces the violacein pigment, and whether intrinsic or exogenous AHLs could influence its production and modulate biofilm-associated phenotypes. Here, we demonstrate that the purple pigment produced by TC14 is violacein. The study shows that in planktonic conditions, TC14 produces more pigment in the medium in which it grows less. Using different approaches, the results also show that TC14 does not produce intrinsic AHLs in our conditions. When exogenous AHLs are added in planktonic conditions, the production of violacein is upregulated by C6-, C12-, 3-oxo-C8 and 3-oxo-C12-HSLs (homoserine lactones), and downregulated by 3-oxo-C6-HSL. In sessile conditions, 3-oxo-C8-HSL upregulates the production of violacein. The study of the biofilm-associated phenotypes shows that oxo-derived-HSLs decrease adhesion, swimming and biofilm formation. While 3-oxo-C8 and 3-oxo-C12-HSLs decrease both swimming and adhesion, 3-oxo-C6-HSLs decrease not only violacein production in planktonic conditions but also swimming, adhesion and more subtly biofilm formation. Therefore, TC14 may possess a functional LuxR-type QS receptor capable of sensing extrinsic AHLs, which controls violacein production, motility, adhesion and biofilm formation.
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Armande
authors: A
authors: Mireille Ayé
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.|Unité Biochimie des Produits Aquatiques (BPA), Université du Littoral Côte d'Opale, Institut Charles Viollette, EA 7394, 62327 Boulogne sur Mer, France.
authors: Maryse
authors: M
authors: Bonnin-Jusserand
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Florence
authors: F
authors: Brian-Jaisson
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Annick
authors: A
authors: Ortalo-Magné
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Gérald
authors: G
authors: Culioli
authors: Laboratoire de Microbiologie et Biotechnologie, Université Nangui-Abrogoua 02 BP 801, Abidjan 02, Côte d'Ivoire.
authors: Rose
authors: R
authors: Koffi Nevry
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Nadia
authors: N
authors: Rabah
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Yves
authors: Y
authors: Blache
authors: Université de Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
authors: Maëlle
authors: M
authors: Molmeret
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism*; D059001:Aquatic Organisms / Q000187:drug effects / Q000502:physiology; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D007211:Indoles / Q000378:metabolism*; D008124:Locomotion; D008522:Mediterranean Sea; D010860:Pigments, Biological / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000187:drug effects* / Q000502:physiology*; D053038:Quorum Sensing
chemical_list: D054742:Acyl-Butyrolactones; D007211:Indoles; D010860:Pigments, Biological; C063155:violacein