title: The interaction of Bacteroides fragilis with components of the human fibrinolytic system.
abstract: Bacteroides fragilis is a minor component of the intestinal microbiota and the most frequently isolated from intra-abdominal infections and bacteremia. Previously, our group has shown that molecules involved in laminin-1 (LMN-1) recognition were present in outer membrane protein extracts of B. fragilis MC2 strain. One of these proteins was identified and showed 98% similarity to a putative B. fragilis plasminogen-binding protein precursor, deposited in the public database. Thus, the objective of this work was to overexpress and further characterize this novel adhesin. The ability of B. fragilis MC2 strain and purified protein to convert plasminogen into plasmin was tested. Our results showed that B. fragilis strain MC2 strain adhered to both LMN-1 and plasminogen and this adhesion was inhibited by either LMN-1 or plasminogen. Regarding the plasminogen activation activity, both the whole bacterial cell and the purified protein converted plasminogen into plasmin similar to streptokinase used as a positive control. Bacterial receptors that recognize plasminogen bind to it and enhance its activation, transforming a nonproteolytic bacterium into a proteolytic one. We present in vitro evidence for a pathogenic function of the plasminogen receptor in promoting adherence to laminin and also the formation of plasmin by B. fragilis.
authors.affiliation: Laboratório Biologia de Anaeróbios, Departamento de Microbiologia Médica, UFRJ, Ilha do Fundão, CCS, Instituto de Microbiologia Prof. Paulo de Góes, Rio de Janeiro, Brazil. eliane_ferreirarj@yahoo.com
authors.forename: Eliane de Oliveira
authors.initials: Ede O
authors.lastname: Ferreira
authors.forename: Joyce Brito
authors.initials: JB
authors.lastname: de Carvalho
authors.forename: Rafael José M
authors.initials: RJ
authors.lastname: Peixoto
authors.forename: Leandro Araujo
authors.initials: LA
authors.lastname: Lobo
authors.forename: Russolina B
authors.initials: RB
authors.lastname: Zingalli
authors.forename: C Jeffrey
authors.initials: CJ
authors.lastname: Smith
authors.forename: Edson R
authors.initials: ER
authors.lastname: Rocha
authors.forename: Regina M C P
authors.initials: RM
authors.lastname: Domingues
mesh_terms: D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001442:Bacteroides Infections / Q000378:metabolism / Q000382:microbiology*; D001441:Bacteroides fragilis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000032:analysis; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D007797:Laminin / Q000378:metabolism; D013058:Mass Spectrometry; D010958:Plasminogen / Q000378:metabolism; D010960:Plasminogen Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D007797:Laminin; C121346:laminin 1; D010958:Plasminogen; D010960:Plasminogen Activators; D005341:Fibrinolysin