490 likes | 993 Views
Biofilms. Dental plaque. Problems associated to biofilms. 1- Physical effects: ships, tubing…. 2- Metal surface corrosion . 3- Development on medical implants. 4- Associated diseases. Tubing obstruction. Equipamiento dental >30años. M +. MS 2-. Biofilm formation on a voice implant.
E N D
Problems associated to biofilms 1- Physical effects: ships, tubing… 2- Metal surface corrosion 3- Development on medical implants 4- Associated diseases
Tubing obstruction Equipamiento dental >30años
M+ MS2-
Genetic analysis of biofilm formation WT LBF MBF HBF Citrate Glucose+Caa
Genetic characterization of biofilm formation - Requirement of movement - Adhesins -Signaling -Glycocalyx formation
Movement requirement • Flagelar-mediated mobility • Non-motile mutants in P. Fluorescens • Twitching • Mutants in type IV pili in P. aeruginosa • Suppression by cells “stickier” • ompR and adhesin Curli in E. coli
Adhesins • Type I pilus (fimH) in E. coli • Type IV (MSHA) pilus in V. cholerae • Curli adhesin
Signaling • Quorum sensing
QUORUM SENSING:DENSITY-DEPENDENT EXPRESSION TRESHOLD AUTOINDUCER CULTURE DENSITY
GRAM-NEGATIVE COMMUNICATION: THE LuxI/LuxR LANGUAGE LuxR LuxR LuxI Target gene
GRAM-NEGATIVE COMMUNICATION: THE LuxI/LuxR LANGUAGE • Light production in Vibrio fisheri • Virulence in Pseudomonas aeruginosa (LasI/R, RhlI/R) • Opine formation in Agrobacterium tumefaciens (TraR/I)
GRAM-positive COMMUNICATION: THE PHEROMONE LANGUAGE H ABC D Pheromone gene Target gene
HYBRID LANGUAGES: THE CASE OF Vibrio harvey LuxQ LuxN LuxLM LuxS LuxO Target gene
GRAM-positive COMMUNICATION: THE PHEROMONE LANGUAGE • Competence for DNA uptake in Bacillus subtilis and Streptoccocus pneumoniae (ComX/ComP/ComA) • Sporulation in Bacillus subtilis • Conjugation in Enteroccus fecalis • Virulence in Staphylococus areus
Glycocalyx formation • Alginate production in P. aeruginosa • EPS in V. cholerae (vps)
lasI rhl vps Curli fimA fimH alg flagella
Natural process of biofilm formation / Control by a blocking analogue