title: Biofilm formation is not a prerequisite for production of the antibacterial compound tropodithietic acid in Phaeobacter inhibens DSM17395.
abstract: OBJECTIVE
  The goal of this study was to investigate if biofilm formation on population level is a physiological requirement for antagonism in Phaeobacter inhibens DSM17395, since the antibiotic compound tropodithietic acid (TDA) is produced by several Roseobacter clade species during growth as multicellular aggregates or biofilms at the air-liquid interface and is induced on single cell level upon attachment.
  
  
  RESULTS
  A mutant library was created by Tn5 transposon insertion and 22 TDA-positive (brown) mutants with decreased biofilm formation or adhesion, and eight TDA-negative (white) mutants with increased biofilm formation or adhesion were selected. None of the selected biofilm-overproducing white mutants showed any antibiotic activity, while all brown mutants with reduced or disabled biofilm formation produced the antibacterial compound. Sequencing analysis indicated that genes that are likely involved in EPS/LPS production, motility and chemotaxis, and redox regulation play a role in biofilm formation and/or adhesion in P. inhibens DSM17395.
  
  
  CONCLUSIONS
  Cell aggregation and biofilm formation are not physiological prerequisites for TDA production.
  
  
  CONCLUSIONS
  This study contributes to the understanding of TDA production in P. inhibens, which has great potential as a probiotic in marine larviculture.
authors.affiliation: National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: M J
authors.initials: MJ
authors.lastname: Prol García
authors.forename: P W
authors.initials: PW
authors.lastname: D'Alvise
authors.forename: A M
authors.initials: AM
authors.lastname: Rygaard
authors.forename: L
authors.initials: L
authors.lastname: Gram
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001422:Bacterial Adhesion / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D005798:Genes, Bacterial; D016296:Mutagenesis; D041902:Rhodobacteraceae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014334:Tropolone / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; C527336:tropodithietic acid; D014334:Tropolone
keywords: Phaeobacter; biofilms; mutagenesis; rosettes; tropodithietic acid