Investigation of the Interaction between Fat body and Ovary Development during Pupal Transformation in Silkworm, Bombyx mori

The insect fat body is the major biosynthetic and storage organ involved in lipid, carbohydrate, amino acid and nitrogen metabolism and protein synthesis. It also actively participates in vitellogenesis and ovary development, synthesizing the soluble precursor for yolk, i.e., vitellogenin in stage specific manner. The continual substance exchange among fat body, hemolymph and ovary is controlled by hormones, ecdysteroids and juvenile hormone, during metamorphosis of Bombyx mori (L.). The aim of the present study was to clarify the interactions between major proteins of fat body and hemolymph and their effect on ovarian development under hormonal factors during pupal-adult transformation. Detected fat body, hemolymph and ovary proteins are grouped as follows by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE): storage proteins (72 kDa and 76 kDa), 30 kDa proteins, ApoLp-I (230-250 kDa), egg specific protein (72 kDa and 64 kDa) and vitellogenins (178 kDa). Our results suggest that changes in the well-defined and characterized protein fractions quality and quantity of the fat body had a direct effect under hormonal factors on the ovary and egg development during metamorphosis.