Effects of heat treatment on the symbiotic system of blattoidea: Morphofunctional alterations of bacteriocytes

Abstract

The purpose of the research was to study the morphological alterations that were produced in the symbiotic equilibrium of individuals of Leucophaea maderae, Periplaneta americana and Nauphoeta cinerea heat-treated at + 39° C. The bacteria localized in the bacteriophorous vacuoles in the bacteriocytes of the samples treated underwent a series of structural modifications that led to protoplast formation. This phenomenon is similar to that which occurs in free-living bacteria. The protoplasts were then further digested into the bacteriophorous vacuoles which had become cytolysosomes, to the point that they became residual bodies. When the process of endocellular lysis involved the whole symbiotic complement, the nucleus and the cytoplasmatic organelles of the bacteriocyte began to degenerate. These alterations were irreversible and could lead to the death of the cell. As a result, the number of bacteriocytes diminished. Heat treatment, which had lethal effects on the bacteria, altered the equilibrium which was established during the process of coevolution between the symbiotic prokaryote and the host cell. The bacteriocyte, deprived of its symbiotic complement, did not survive the loss of its morphofunctional equilibrium. © 1993 Taylor & Francis Group, LLC.