Cytochemistry of Gastrodermal Autophagy Following Starvation in Schistosoma mansoni

Abstract

The gastrodermis of adult Schistosoma mansoni was examined by electron microscopy to determine the effects of starvation and the effects of hycanthone, administered in vitro. Special attention was focused on the relationship of the Golgi complexes with the process of autophagy. In general, autophagy was increased in the gastrodermis when it was exposed to stress conditions such as starvation and hycanthone. Acid phosphatase and thiamine pyrophosphatase activities were used as enzyme markers for the Golgi complexes and lysosomes. During the early stages of starvation, there was a 4-fold increase in the number of Golgi complexes per unit area in the gastrodermis. A progressive increase in the number of secondary lysosomes was evident as starvation time was increased. Hycanthone accelerated the effects of starvation. It was hypothesized that acid hydrolases are passed to the Golgi complexes via ER-derived vesicles. The enzymes are subsequently released as primary lysosomes from the Golgi complex to fuse with cytosegresomes and form secondary lysosomes (cytosomes).

Transmission electron microscopic observations on ultrastructural alterations in Schistosoma mansoni adult worms recovered from C57BL/6 mice treated with radiation-attenuated vaccine and/or praziquantel in addition to passive immunization with normal and vaccinated rabbit sera against infection

“…Finally, the lumen of gastrodermis in the VR group appeared narrow with high intensity of cytoplasmic extensions and amoeboid shape of nucleus. The increase in number of gastrodermal vacuoles has been documented by Bogitsh (1975) and Clarkson and Erasmus (1984).…”

The proteasome-ubiquitin pathway in the Schistosoma mansoni egg has development- and morphology-specific characteristics

“…Autophagy is a more feasible process than apoptosis for vitelline cell degradation because almost all of the autophagic components have been found in the transcriptome and autophagy is known to occur in adult schistosomes [42,44,45]. Autophagy eliminates unwanted cells during developmental cell death in various taxa, including the ovarian nurse cells in Bombyx mori and Ceratitis capitata [46][47][48].…”

Anti-Schistosomal Activity of Cinnamic Acid Esters: Eugenyl and Thymyl Cinnamate Induce Cytoplasmic Vacuoles and Death in Schistosomula of Schistosoma mansoni

“…However, only the bornyl (3), menthyl (25,26), thymyl (23) and eugenyl cinnamates (27) induced the severest phenotypes. Accordingly, the existence of a Michael system does not necessarily lead to anti-schistosomal activity.…”

“…There are few reports on autophagy in S. mansoni. Autophagy is inducible in S. mansoni schistosomula upon starvation [25] and large acidophilic compartments [26,27] are detectable using the fluorescent dye monodansylcadaverine, a relatively specific dye for autophagosomes [28]. Exposure of S. mansoni adult worms to astiban, lucanthone, hycanthone, and niridazole generate autophagic activities in the gastrodermis (gut) of S. mansoni and induce autophagic vacuoles [29].…”