Silk proteins were isolated from the silk glands and cocoons by the method described by Rajan et al. (1992). Briefly 1-
g of silk gland or 1-g of cocoons from each from each hybrid was suspended in 50 ml 0.025 N NaOH solution and
stirred for 12 hours at 4 0C. The soluble protein was extensively dialyzed against double distilled water, concentrated
under vacuum and stored at -20oC until use. Alternatively, sericin was extracted by boiling the cocoon fibers in 0.025
percent Na2CO3 solution for 1 hour followed by dialysis and concentration, as described by Tashiro et al. (1968).