PROTEASES RELEASED BY LUCILIA-CUPRINA DURING EGG HATCH

Products released by Luclia cuprina (sheep blowfly) during egg hatch a nd early larval development were found to contain a variable number of proteases, probably reflecting their different functions during these developmental phases. Moreover, a number of the developmentally regul ated proteases produced only during egg hatch appeared to be strongly egg shell associated, indicating the egg shell proteins to be their sp ecific substrates. Several proteases were tested for their ability to enhance the rate of egg hatch. The commercial proteases chymotrypsin a nd trypsin were able to significantly enhance (p less than or equal to 0.01) egg hatch by 36% and 44%, respectively, when compared to an unt reated control. Interestingly, fluids containing the egg shell associa ted proteases were able to significantly (p less than or equal to 0.00 1) enhance L. cuprina egg hatch by up to 70%, This hatch enhancement a ctivity could be significantly (p less than or equal to 0.001) reverse d by the addition of Phenylmethylsulphonyl fluoride (PMSF), Fractionat ion of the egg-associated proteases by gelatin affinity chromatography suggested that gelatin-binding molecules were responsible for the maj ority of the egg hatch enhancement activity in this preparation. (C) 1 998 Elsevier Science Ltd. All rights reserved.