Synthesis and chemical composition of mucus gland secretions in Apis cerana indica

The columnar epithelial cells of the mucus gland begin to synthesize secretory material in the late pupal stage, and this material gradually accumulates in the lumen, beginning soon after emergence of the adult drones. Histochemical tests demonstrated secretory activity in the epithelial cells and revealed the biochemical nature of the secretions as a mixture of proteins, carbohydrates and lipids. Total proteins, lipids and carbohydrates were detected in concentrations of 333.2 +/- 13.883, 208.60 +/- 11.69 and 44.82 +/- 2.94 mu g/mg, respectively, showing that proteins form the major constituents of the mucus gland secretory material. SDS-PAGE of mucus gland secretory material revealed about 15 proteins of molecular weight ranging from 2.5 to 151.2 kDa. Three proteins of 45, 43 and 37 kDa were stained intensely and can be considered as the major class of mucus proteins.