title: In situ analysis of Bacillus licheniformis biofilms: amyloid-like polymers and eDNA are involved in the adherence and aggregation of the extracellular matrix.
abstract: OBJECTIVE
  This study attempts to determine which of the exopolymeric substances are involved in the adherence and aggregation of a Bacillus licheniformis biofilm.
  
  
  RESULTS
  The involvement of extracellular proteins and eDNA were particularly investigated using DNase and proteinase K treatment. The permeability of the biofilms increased fivefold after DNase I treatment. The quantification of the matrix components showed that, irrespective to the enzyme tested, eDNA and amyloid-like polymers were removed simultaneously. Size-exclusion chromatography analyses supported these observations and revealed the presence of associated nucleic acid and protein complexes in the biofilm lysates. These data suggest that some extracellular DNA and amyloid-like proteins were closely interlaced within the matrix. Finally, confocal laser scanning microscopy imaging gave supplementary clues about the 3D organization of the biofilms, confirming that eDNA and exoproteins were essentially layered under and around the bacterial cells, whereas the amyloid-like fractions were homogeneously distributed within the matrix.
  
  
  CONCLUSIONS
  These results confirm that some DNA-amyloid complexes play a key role in the modulation of the mechanical resistance of B. licheniformis biofilms.
  
  
  CONCLUSIONS
  The study highlights the need to consider the whole structure of biofilms and to target the interactions between matrix components. A better understanding of B. licheniformis biofilm physiology and the structural organization of the matrix will strengthen strategies of biofilm control.
authors.affiliation: LBAE, Laboratoire de Biotechnologies Agroalimentaire et Environnementale, Institut Universitaire de Technologie, Université de Toulouse, UPS, Auch, France.
authors.forename: I
authors.initials: I
authors.lastname: Randrianjatovo-Gbalou
authors.affiliation: LBAE, Laboratoire de Biotechnologies Agroalimentaire et Environnementale, Institut Universitaire de Technologie, Université de Toulouse, UPS, Auch, France.
authors.forename: P
authors.initials: P
authors.lastname: Rouquette
authors.affiliation: LBAE, Laboratoire de Biotechnologies Agroalimentaire et Environnementale, Institut Universitaire de Technologie, Université de Toulouse, UPS, Auch, France.
authors.forename: D
authors.initials: D
authors.lastname: Lefebvre
authors.affiliation: LBAE, Laboratoire de Biotechnologies Agroalimentaire et Environnementale, Institut Universitaire de Technologie, Université de Toulouse, UPS, Auch, France.
authors.forename: E
authors.initials: E
authors.lastname: Girbal-Neuhauser
authors.affiliation: LBAE, Laboratoire de Biotechnologies Agroalimentaire et Environnementale, Institut Universitaire de Technologie, Université de Toulouse, UPS, Auch, France.
authors.forename: C-E
authors.initials: CE
authors.lastname: Marcato-Romain
mesh_terms: D000069976:Bacillus licheniformis / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D001422:Bacterial Adhesion; D018441:Biofilms; D001704:Biopolymers / Q000096:biosynthesis*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000382:microbiology*
chemical_list: D001704:Biopolymers; D004269:DNA, Bacterial
keywords: 
  Bacillus
  ; 3D organization; biofilms; biopolymers; enzymes