title: The marine bacteria Shewanella frigidimarina NCIMB400 upregulates the type VI secretion system during early biofilm formation.
abstract: Shewanella sp. are facultative anaerobic Gram-negative bacteria, extensively studied for their electron transfer ability. Shewanella frigidimarina has been detected and isolated from marine environments, and in particular, from biofilms. However, its ability to adhere to surfaces and form a biofilm is poorly understood. In this study, we show that the ability to adhere and to form a biofilm of S. frigidimarina NCIMB400 is significantly higher than that of Shewanella oneidensis in our conditions. We also show that this strain forms a biofilm in artificial seawater, whereas in Luria-Bertani, this capacity is reduced. To identify proteins involved in early biofilm formation, a proteomic analysis of sessile versus planktonic membrane-enriched fractions allowed the identification of several components of the same type VI secretion system gene cluster: putative Hcp1 and ImpB proteins as well as a forkhead-associated domain-containing protein. The upregulation of Hcp1 a marker of active translocation has been confirmed using quantitative reverse transcription polymerase chain reaction. Our data demonstrated the presence of a single and complete type VI secretion system in S. frigidimarina NCIMB400 genome, upregulated in sessile compared with planktonic conditions. The fact that three proteins including the secreted protein Hcp1 have been identified may suggest that this type VI secretion system is functional.
authors.affiliation: Université de Toulon, MAPIEM, EA4323, 83957, La Garde, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Linares
authors.affiliation: PROTEE, EA3819, 83957, La Garde, France.
authors.forename: Natacha
authors.initials: N
authors.lastname: Jean
authors.affiliation: Université de Toulon, MAPIEM, EA4323, 83957, La Garde, France.
authors.forename: Perrine
authors.initials: P
authors.lastname: Van Overtvelt
authors.affiliation: UMR 6270 CNRS, Laboratoire Polymères, Biopolymères, Surfaces, Université de Rouen, Mont-Saint-Aignan, F-76820, France.
authors.forename: Tassadit
authors.initials: T
authors.lastname: Ouidir
authors.affiliation: UMR 6270 CNRS, Laboratoire Polymères, Biopolymères, Surfaces, Université de Rouen, Mont-Saint-Aignan, F-76820, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Hardouin
authors.affiliation: Université de Toulon, MAPIEM, EA4323, 83957, La Garde, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Blache
authors.affiliation: Université de Toulon, MAPIEM, EA4323, 83957, La Garde, France.
authors.forename: Maëlle
authors.initials: M
authors.lastname: Molmeret
mesh_terms: D000693:Anaerobiosis; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D002462:Cell Membrane / Q000737:chemistry; D003470:Culture Media / Q000737:chemistry; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000032:analysis; D020543:Proteome / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012623:Seawater / Q000382:microbiology; D020592:Shewanella / Q000235:genetics* / Q000502:physiology*; D000069376:Type VI Secretion Systems / Q000235:genetics* / Q000378:metabolism*
chemical_list: D003470:Culture Media; D008565:Membrane Proteins; D020543:Proteome; D000069376:Type VI Secretion Systems