Functional characterization of extracellular vesicles produced by Bacteroides gingivalis

Abstract

Extracellular vesicles of Bacteroides gingivalis (type strain 33277) were isolated, and some of their biological activities were characterized. The vesicles were obtained from a 2-day culture after ammonium sulfate precipitation, differential centrifugation, and dialysis. When viewed by electron microscopy, vesicles of approximately 50 nm predominated. The results indicated that the enriched vesicle fraction had a high proteolytic activity against collagen, Azocoll, and N-a-benzoyl-DL-arginine p-nitroanilide. The polypeptide pattern of the vesicles was similar but not identical to that of the outer membrane. The membrane vesicles could also promote bacterial adherence between homologous cells as well as mediate attachment between two noncoaggregating bacterial species. These vesicles could thus play an important role in periodontal diseases by serving as a vehicle for toxins and various proteolytic enzymes, as well as being involved in adherence.

Surface properties and ultrastructure of Porphyromonas gingivalis W50 and pleiotropic mutants

“…It seems likely therefore that the haemagglutinin receptor is associated with the outer membrane proteins of P. gingwalis. Haemagglutinin is inhibited at low concentrations of arginine (7,17) and it has been suggested that arginine ftmctions as an active residue between the haeterial receptor and erythrocytes (3).…”

Arginine-specific gingipains from Porphyromonas gingivalis deprive protective functions of secretory leucocyte protease inhibitor in periodontal tissue

“…Bacterial vesicles were prepared according to the method described by Grenier and Mayrand [47]. Briefly, bacterial cells were first removed from the growth media by centrifugation (10 000 g for 15 min) and then ammonium sulphate was added to the culture supernatant.…”

Adherence and invasion of Bacteroidales isolated from the human intestinal tract

“…Surface vesicles have been observed in oral bacteria, e.g. Porphyromonas gingivalis, and it has been suggested that there is an association between those structures and biological activities, such as proteolysis, haemagglutination and co-aggregation [28]. Encapsulated Bacteroides species are most often found in abdominal abscesses and the bloodstream, but have been reported in isolates from resident intestinal microbiota [20].…”