title: A TonB-dependent outer membrane protein as a Bacteroides fragilis fibronectin-binding molecule.
abstract: The binding of Bacteroides fragilis to plasmatic fibronectin was investigated using strains isolated from healthy subjects and from patients with bacteremia. They were cultivated in a synthetic media in which variations in cysteine concentrations determined alterations in the oxidation-reduction potential (Eh). All the strains assayed were capable of adhering to plasmatic fibronectin when cultivated under oxidizing and reducing conditions. Bacteroides fragilis 1405 showed the greatest difference when the results under these conditions were compared and it was selected for further investigations. Chemical treatments suggested the involvement of a protein in the interaction between B. fragilis and plasmatic fibronectin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of outer membrane proteins (OMPs) revealed differences between the extracts obtained from cultures grown under the two conditions. Protein bands of c. 102, 100, 77, 73, 50 and 40 kDa were more highly expressed under oxidizing than reducing conditions. Dot blot analysis showed a stronger recognition of plasmatic fibronectin by OMPs obtained from cultures grown under higher Eh, and Western blot assays confirmed a band of c. 102 kDa as fibronectin-binding protein. This protein was sequenced and revealed to be a putative TonB-dependent OMPs. PCR analysis confirmed the presence of this gene in all the studied strains.
authors.affiliation: Departamento de Microbiologia Médica, Laboratório de Biologia de Protistas, Instituto de Microbiologia Prof Paulo de Góes/UFRJ, Rio de Janeiro, Brazil. heidipauer@gmail.com
authors.forename: Heidi
authors.initials: H
authors.lastname: Pauer
authors.forename: Eliane de Oliveira
authors.initials: Ede O
authors.lastname: Ferreira
authors.forename: Joaquim
authors.initials: J
authors.lastname: dos Santos-Filho
authors.forename: Maristela Barbosa
authors.initials: MB
authors.lastname: Portela
authors.forename: Russolina Benedeta
authors.initials: RB
authors.lastname: Zingali
authors.forename: Rosangela Maria Araújo
authors.initials: RM
authors.lastname: Soares
authors.forename: Regina Maria Cavalcanti Pilotto
authors.initials: RM
authors.lastname: Domingues
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001441:Bacteroides fragilis / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D004269:DNA, Bacterial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008970:Molecular Weight; D016133:Polymerase Chain Reaction / Q000379:methods; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D005353:Fibronectins; D037521:Virulence Factors; C078635:fibronectin-binding proteins, bacterial