Proteases released by Lucilia cuprina during egg hatch

Products released by Luclia cuprina (sheep blowfly) during egg hatch and 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 regulated proteases produced only during egg hatch appeared to be strongly egg shell associated, indicating the egg shell proteins to be their specific substrates. Several proteases were tested for their ability to enhance the rate of egg hatch. The commercial proteases chymotrypsin and trypsin were able to significantly enhance (p≤0.01) egg hatch by 36% and 44%, respectively, when compared to an untreated control. Interestingly, fluids containing the egg shell associated proteases were able to significantly (p≤0.001) enhance L. cuprina egg hatch by up to 70%. This hatch enhancement activity could be significantly (p≤0.001) reversed by the addition of Phenylmethylsulphonyl fluoride (PMSF). Fractionation of the egg-associated proteases by gelatin affinity chromatography suggested that gelatin-binding molecules were responsible for the majority of the egg hatch enhancement activity in this preparation.