The effect of juvenile hormone analog fenoxycarb on the posterior silk gland during larval pupal development period of silkworm Bombyx mori

Silk gland has a structure which continues through the body on the silkworm Bombyx mori and it is degenerated during the larval pupal metamorphosis. This degeneration controlled by the endocrine system occurs via programmed cell death. The two main hormones that control this process are 20-hydroxyecdysone and juvenile hormones. The silk gland is an ectodermal originated tissue which is characterized by nuclei with branched structure. The posterior side of the gland is closed. On the other hand the anterior side provides release out the silk secretion in a single fiber by combining just before the opening out the of the front. Posterior silk gland is responsible for the secretion of fibroin protein. In order to identify the relation between endocrine system and the metamorphic changes in posterior silk gland during larval-pupal metamorphosis, juvenile hormone analogue fenoxycarb was applied with a single dose at the beginning of the last larval stage. In our study, the morphological changes in the posterior silk gland were shown during larval-pupal metamorphosis by using histological techniques. The activity of acid phosphatase enzyme, which is a lysosomal enzyme, was measured. Furthermore, the total protein profile of the posterior silk gland was revealed by the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method. In the study, the role of the endocrine system was investigated during the programmed cell death in the posterior silk gland of silkworm Bombyx mori. Keywords: Bombyx mori, fenoxycarb, silk gland, apoptosis, autophagy, acid phosphatase, SDS-PAGE