Occurrence of apoptosis in serosa of Periplaneta americana l. (Blattaria: blattidae): ultrastructural and biochemical features.

In 16-17-day-old embryos of Periplaneta americana, the amnion-serosa penetrates the cavity of the middle intestine, where it forms a cluster of compressed roundish cells. We demonstrated that these cells degenerate throughout apoptosis. The programmed cell death revealed by morphological and biochemical approaches showed all the apoptotic steps: chromatin fragmentation and pyknosis, cytoplasm condensation, karyorrhexis, cytoplasm cleavage.

Some aspects of intracellular symbiosis during embryo development of Mastotermes darwiniensis (Isoptera: Mastotermitidae).

All examined species of cockroaches have been shown to harbour intracellular bacteria in specialized cells (bacteriocytes) of the fat body. In termites, bacteria in specialized cells have been observed only in Mastotermes darwiniensis (Isoptera: Mastotermitidae). All of these bacteria have been assigned to the same eubacterial lineage, with the bacteria of M.

The establishment of intracellular symbiosis in an ancestor of cockroaches and termites.

All cockroaches examined so far have been found to harbour a bacterial endosymbiont in specialized cells of the fat body, whereas Mastotermes darwiniensis is the only termite currently known to harbour an intracellular symbiont. The localization and mode of transmission of these bacteria are surprisingly similar, but so far no data have been published on their phylogenetic relationships. To address this issue, molecular sequence data were obtained from the genes encoding the small subunit ribosomal RNA of the M.

Distribution and pharmacological properties of the GABAA/benzodiazepine/chloride ionophore receptor complex in the brain of the fish Anguilla anguilla.

In the present study, we characterized the distribution and the pharmacological properties of the different components of the GABAA receptor complex in the brain of the eel (Anguilla anguilla). Benzodiazepine recognition sites labeled "in vitro" with [3H]flunitrazepam ([3H]FNT) were present in highest concentration in the optic lobe and in lowest concentration in the medulla oblongata and spinal cord. A similar distribution was observed in the density of gamma-[3H]aminobutyric acid ([3H]GABA) binding sites.

Histochemical demonstration of oxidoreductase activities in the fat body and symbionts of Blattella germanica (Blattodea) following chlortetracycline-treatment.

The metabolic apport of prokaryotic symbionts in the fat body of Blattella germanica was investigated by histoenzymatic methods, using chlortetracycline-treated and normal strains. In the experimental insects, bacteriocytes showed a decreased oxidoreductase activity, whereas the staining intensity of the other cell types was generally unchanged. Electron microscopic observations showed that some bacteria were still present in the bacteriocytes of the treated insects, but exhibited degeneration patterns to a different extent; therefore, they are not likely to carry on any enzymatic activity.