Determination of protein concentration
Total protein concentration was determined by the Bradford microassay protocol (Bradford, 1976) using the Quick Startâ„¢ Bradford reagent (BioRad, Hercules, CA, USA). The samples used were crude larval extract and the purified S fraction. Additionally, the concentration of purified S protein was determined in an SDS-PAGE image with a diluted series of control bovine serum albumin.