Histological damage by the microbial metabolite and chitin synthesis inhibitor complex nikkomycin to the silk and salivary glands of the mite Tetranychus urticae

Abstract

The action of the chitin synthesis inhibitor complex nikkomycin on the silk and salivary glands of Tetranychus urticae (Acari, Tetranychidae) was examined with the electron microscope. Histological defects after nikkomycin treatment included a swelling of the cisterna of rough endoplasmic reticulum (ER). Subsequent defects were vacuolation, resulting from globular ER vesicles, and damage to the secretory grana of all the glands studied (the silk gland and the anterior and dorsal podocephalic glands). The consequences of the histological changes on the salivary secretions and the production of webs are discussed.

Comparative histopathology of the chitin synthesis inhibitors nikkomycin X/Z, nikkomycin Z and polyoxin D. I: Effects on moulting, reproduction and digestion in the spider mite Tetranychus urticae

“…Histological defects following nikkomycin X/Z uptake included swelling of the cisternae of rough ER, subsequent vesiculation, and damage to the secretory grana. 16 The effects of nikkomycin Z on the silk gland resembled those of nikkomycin X/Z. However, polyoxin D seriously damaged the ultrastructure of the gland.…”

“…Consequences may include firstly, effects on predigestion, food uptake and metabolism and, secondly, influences on egg deposition due to the lack of production of webs. 16 The sites of the first contact between ingested compounds and unprotected target tissue are the ventricle and the caeca. Here, there is no doubt about a difference in action between the nikkomycins and polyoxin D. Defects in the epithelial cells due to the nikkomycins are small.…”