Exogenous prostaglandin F 2α as a mediator in the regulation of silkworm growth and silk gland genome

Abstract

Prostaglandins are locally acting hormones that have remarkable variety of physiological functions. They are rapidly synthesized in several types of vertebrate cells as oxygenated metabolites of arachidonic acid in response to various stimuli. In many insect species they are biosynthesized in fat body and hemocytes mainly in response to bacterial infections. In the present study, we administered synthetic analog of prostaglandin F 2α, the most prominent of the prostaglandins to the 48 h old fifth instar silkworm, Bombyx mori L. at a single dose of 4 μg per larva to study its effects on the larval growth pattern and silk synthesis. The possible role of PGF 2α at altering the quantum of silk synthesis by controlling the silk gene expression was also studied. The genomic DNA was isolated from the posterior silk gland on Days 5 and 7 of the fifth instar from the prostaglandin treated and the control larvae and were random amplified with arbitrary primers. The result presented notable variation in the amplified product suggesting the participation of PGF 2α in the silk biosynthesis controlling the silk gene expression. The feeding period of treated larvae was unaffected while the cocoon characters exhibited considerable improvement. The filament traits also were improved notably in the treated larvae. The participation of PGF 2α analog in the silk biosynthetic process with its physiological and molecular implications are discussed.