[Experimental induction of rotund bodies in Thermus equaticus].

With several isolates of T. aquaticus rotund bodies (rbs) have been artificially induced. The most active agents were lysozyme, pronase (not trypsin), cellulase (not alpha-amylase or beta-glucosidase), penicillin and some mineral salts. Two modifications of rbs were observed: the vesticular type arising from single cells or filaments and the aggregate-rbs resulting from secondary associations of several cells or filaments. In both cases the primary event is a partial detachment of the outer layer of cell envelopes followed by its swelling to form a hyaline bleb. Within these osmotically stable blebs cells and/or filaments involved in the ribs production become irreversibly trapped. Appearance of filaments and rbs in stationary phase cultures are discussed as a consequence of unbalanced growth culminating in abnormal autolytic reactions.