title: Impact of the exopolysaccharide layer on biofilms, adhesion and resistance to stress in Lactobacillus johnsonii FI9785.
abstract: BACKGROUND
  The bacterial cell surface is a crucial factor in cell-cell and cell-host interactions. Lactobacillus johnsonii FI9785 produces an exopolysaccharide (EPS) layer whose quantity and composition is altered in mutants that harbour genetic changes in their eps gene clusters. We have assessed the effect of changes in EPS production on cell surface characteristics that may affect the ability of L. johnsonii to colonise the poultry host and exclude pathogens.
  
  
  RESULTS
  Analysis of physicochemical cell surface characteristics reflected by Zeta potential and adhesion to hexadecane showed that an increase in EPS gave a less negative, more hydrophilic surface and reduced autoaggregation. Autoaggregation was significantly higher in mutants that have reduced EPS, indicating that EPS can mask surface structures responsible for cell-cell interactions. EPS also affected biofilm formation, but here the quantity of EPS produced was not the only determinant. A reduction in EPS production increased bacterial adhesion to chicken gut explants, but made the bacteria less able to survive some stresses.
  
  
  CONCLUSIONS
  This study showed that manipulation of EPS production in L. johnsonii FI9785 can affect properties which may improve its performance as a competitive exclusion agent, but that positive changes in adhesion may be compromised by a reduction in the ability to survive stress.
authors: Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Colney, Norwich, NR4 7UA, UK. edertli@bayburt.edu.tr.|Department of Food Engineering, Faculty of Engineering, Bayburt University, Bayburt, Turkey. edertli@bayburt.edu.tr.
authors: Enes
authors: E
authors: Dertli
authors: Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Colney, Norwich, NR4 7UA, UK. melinda.mayer@ifr.ac.uk.
authors: Melinda J
authors: MJ
authors: Mayer
authors: Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Colney, Norwich, NR4 7UA, UK. arjan.narbad@ifr.ac.uk.
authors: Arjan
authors: A
authors: Narbad
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D002645:Chickens; D007422:Intestines / Q000382:microbiology; D007778:Lactobacillus / Q000378:metabolism / Q000502:physiology*; D050296:Microbial Viability; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D011135:Polysaccharides, Bacterial
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