Alpha Amylase Development in Embryos of Crassostrea virginica

Numerous investigations of changes in enzyme activity during development have been made during recent years. Such studies have been reviewed by Moog (1958, 1959), LØvtrup (1959) and Brachet (1960). Relatively few quantitative investigations have been made of enzymes in embryonic invertebrates; we there fore have little knowledge of enzymic changes which are temporally associated with visible morphogenetic events in these embryos. In this paper, data on the levels of alpha amylase in several developmental stages of the oyster are presented. This enzyme is present in considerable concen tration in the crystalline style, a mucoprotein rod secreted in a diverticulum of the intestine of adult pelecypods and some gastropods (Yonge, 1926; Prosser and Brown, 1961). It was therefore of interest to determine whether any change in amylase activity accompanied the development of the larval intestine. It was also of some interest to determine whether a high activity of this enzyme would be found in larvae which had not yet begun feeding, since the levels of digestive enzymes in various adult animals sometimes depend on the presence of appropriate foods (cf. van Weel, 1961; Prosser and Brown, 1961)