Development and Protein Synthesis of Colleterial Glands in the Female Silkmoth, Bombyx mori (Lepidoptera: Bombycidae)

Abstract

The daily changes of the weight, protein concentration and nucleic acids content in the colleterial glands of the female silkmoth, Bombyx mori, were investigated. The weight of the glands increased lineally up to the adult eclosion, and then decreased with age. The protein content in the glands increased in parallel with the change of the weight of the glands. The ratio of the protein content to the weight of glands was almost constant, with values of 4 to 6%. On day 6 of pupal-adult development, the RNA content in the glands increased rapidly, then dropped after eclosion. However, the daily changes of the DNA content in the glands were scarce. High rates of the incorporation of labelled amino acid (¹⁴C-U-leucine) into the protein fraction were observed in the arborescent regions of the glands. This result confirmed that these regions were the source of the protein synthesis and that the colleterial substances were stored in the gland reservoir. Although about 40 bands on the SDS-PAGE were detected in the homogenates of the glands, it seems likely that a protein with 300kd molecular weight was the main product of the colleterial glands.