AMPHIBIAN AND INVERTEBRATE DEVELOPMENT 9 5
material were studied in our laboratory, and sufficient data are not yet
available to provide a comprehensive picture of hydrolase activity
during embryonic development. AG dipeptidases and Upases show a
remarkable similarity in the pattern of activity; both decrease during
the initial stages of embryonic development and then increase rapidly;
after complete yolk resorption, there is a rapid fall in activity.
Amylase activity is relatively constant during the first half of
embryonic development, and then increases sharply. This increase can
almost certainly be attributed to the differentiation of the gut.
The changes are shown graphically in Fig. 18. We should add that
Bombyx mori
1 Lipase
2 AG dipeptidase
Time of development
FIG. 18. Enzyme activity, expressed in arbitrary units, during the embryonic development (E) and larval growth (L) of Bombyx mori (Urbani and Rossi, 1959; Oaeta and
Zappanico, 1959; Magni-Polzonetti and Pettinari, 1960).
Time of development
FIG. 19. Changes in total nitrogen (TN), total carbohydrates (TC) and total lipids (TL)
during the embryonic development (E) and larval growth (L) of Bombyx mori. Initial
content: 100 (Urbani and Bellini, 1959).