Capnocytophaga gingivalis aminopeptidase: a potential virulence factor

Abstract

The production and properties of an aminopeptidase from Capnocytophaga gingiwalis were studied. C. gingiveris was grown in continuous culture over a range of dilution rates and the cell-bound and extracellular levels of Frenchay Campus, . Coldharbour Lane, Bristol BS16 lQY, UK aminopeptidase and trypsin-like protease (TLPase) measured. A t high growth rates (06 pm,) TLPase specific activity was low and found exclusively as cellbound activity; at low growth rates (09375 pd), specific activity was high and 26 O/ O was found as extracellular activity. In contrast, aminopeptidase specific activity was highest at 0-3 pm, and the ratio of cell-bound to extracellular activity was relatively constant at all growth rates. Only about 5% of the total activity was extracellular. The aminopeptidase, which has a wide specificity towards artificial substrates, was purified to homogeneity, as judged by SDS-PAGE, from the supernatant fluid of cells grown in continuous culture in a tryptone/glucose!thiamine medium. The enzyme has a molecular mass of 61 kDa, a pl of 63, a pH optimum close to 7.5 and showed a requirement for magnesium or calcium ions. The N-terminal sequence of the first 10 amino acids (Asp-Val-Asn-Met-Leu-Trp-Tyr-Val-x-Arg ...) showed no similarity to any published sequence. This enzyme in its cell-bound or extracellular form may be important in the nutrition and pathogenesis of C. gingiwdis in the human oral cavity.

The presence of bacteria within tissue provides insights into the pathogenesis of oral lichen planus

“…Among the bacterial species increased in the OLP mucosa, a periodontal pathogen T. denticola damages the epithelial physical barriers, which involves bacterial proteases 28 . C. gingivalis has a trypsin-like protease 29 that may degrade the junctional proteins. Therefore, the bacterial invasion of mucosal tissues observed in OLP may be associated with the changes in the mucosal microbiota as well as with degeneration/atrophy of epithelial cells.…”

Microbiological, immunological and genetic factors in family members with periodontitis as a manifestation of systemic disease, associated with hematological disorders

“…Ashimoto et al (16) also suggested that C. rectus may be an endogenous pathogen that occasionally contributes to the development of periodontitis, while Hinode et al (38) reported that GroEL-like protein might be a virulence factor of C. rectus in periodontal disease. Spratt et al (39) suggested that trypsin-like protease might be important in the pathogenesis of C. gingivalis in the human and oral cavity, and Okuda et al (40) found that C. gingivalis possessed a hemagglutinating activity, while C. ochracea did not. Conrads et al (17) reported that, with a PCR approach, C. gingivalis was not detected in children aged 3-10 years.…”

Role of bacterial proteinases in matrix destruction and modulation of host responses

“…However, before they can be utilized by any bacterium they must first be degraded into free amino acid, which can then enter the fermentation pathway inside the organism (112). This process is achieved by the joint action of oligopeptidases and exopeptidases that are commonly produced by microorganisms, including bacterial species frequently found in subgingival dental plaque such as Fusobacterium nucleatum (300), Capnocytophaga gingivalis (336), B. forsythus, T. denticola and P. gingivalis ( Table 2). In the two latter species, both exopeptidases and endopeptidases form a complex proteolytic system that may play a major role in periodontitis.…”