| Protease activity is present in the excretory-secretory (ES) products and extracts (X) of Trichinella spiralis preadults (PA). However, other Trichinella life cycle stages invade host tissues. Migratory actions of the stages may dictate the method of cell invasion. We examined three life cycle stages of T. spriralis and T. pseudospiralis for protease activity using a fluorometric assay. Protease activity in the newborn larval (NBL) stage ES and X of both species was greater than PA and adult (A) stages. Diversity of proteases within each sample was demonstrated by different pH optima and zymogram gels which revealed multiple protease bands for each sample, some of which were unique between samples. The PA and NBL samples were partially inhibited by A-phenylmethansulfonyl floride, suggesting the presence of at least one serine class protease for both stages. Finally, the PA samples and the NBL X of both species showed cleavage of actin and myosin. |
