MEMBRANE SYSTEMS IN ENDOCYTOBIOSIS .3. ULTRASTRUCTURAL FEATURES OF SYMBIONTS AND VACUOLAR MEMBRANE IN BACTERIOCYTES OF THE WOOD-EATING COCKROACH CRYPTOCERCUS-PUNCTULATUS (DICTYOPTERA, CRYPTOCERCIDAE)

This paper reports the first ultrastructural investigation of bacterio cytes of a member of the genus Cryptocercus. The study of thin section s and freeze-fracture replicas revealed that the symbionts are sequest ered intracellularly within a vacuolar system. Aggregates of intra-mem brane particles on the E-fracture face, close sites of adhesion, and a process of vesiculation have been evidenced on the vacuolar membrane. Moreover, a blebbing process of the symbiont outer membrane is descri bed and the results are compared to those obtained from previously exa mined cockroaches.