Membrane systems in endocytobiosis iii. Ultrastructural features of symbionts and vacuolar membrane in bactériocytes of the wood-eating cockroach cryptocercus punctulatus (dictyoptera, cryptocercidae)

This paper reports the first ultrastructural investigation of bactériocytes of a member of the genus Cryptocercus. The study of thin sections and freeze-fracture replicas revealed that the symbionts are sequestered intracellularly within a vacuolar system. Aggregates of intra-membrane particles on the E-fracture face, close sites of adhesion, and a process of vésiculation have been evidenced on the vacuolar membrane. Moreover, a blebbing process of the symbiont outer membrane is described and the results are compared to those obtained from previously examined cockroaches.