Detection of stress proteins inPorphyromonas gingivalisand other oral bacteria by Western immunoblotting analysis

Detection of stress proteins in Porphyromonas gingivalis was investigated by SDS-PAGE and Western immunoblotting procedure using a polyclonal antibody (anti hsp60) and a monoclonal antibody (anti-Dnak). Results indicate that P. gingivalis can elicit a hsp60-like stress protein when submitted to different environmental stresses such as a heat shift from 35 degrees C to 43 degrees C, a pH drop from 7.2 to 6.0 or an increase in oxygen concentration. Virulent and non-virulent strains of P. gingivalis responded the same way. The other bacterial species tested also showed an increased synthesis of a GroEL-like protein after heat shock, as detected by the anti hsp60 antibody. However, the monoclonal anti-Dnak recognized an hsp70-like protein only in two of the tested species.