Abstract
Large quantities of Prevotella nigrescens ATCC 25261 (P. nigrescens) cells adhere to hydroxyapatite (HA) treated with extract from Porphyromonas gingivalis 381 (Pg-Ext), but not to HA coated with human serum albumin (HSA) or human serum globulin (HSG). The duration of HA treatment with Pg-Ext and several other conditions were tested to determine the factors causing Pg-Ext to promote P. nigrescens cell adhesion. Pg-Ext adsorbed rapidly to HA in less than 5 min. The maximum adherence of P. nigrescens cells to HA was observed after treatment of HSA and HSG and then retreatment of HA with Pg-Ext. It was found that Pg-Ext heated at 80°C for 30 min did not lose its propensity to promote attachment of P. nigrescens to HA and that it also remained stable at 4°C for at least 6 days. The trypsin-like enzyme activity of Pg-Ext was also measured, with BAPNA as the substrate and commercially purchased trypsin as the standard, and was approximately 0.12 units/mg. These data suggest that the presence of Pg-Ext is one of the essential factors responsible for P. nigrescens cell attachment to apatitic surfaces, and that with its trypsin-like activity, Pg-Ext may be considered an extremely important substance for the establishment of P. nigrescens in the periodontal pocket and the development of periodontal disease. (J. Oral Sci. 45, 99-106, 2003)
