254
SILVIO RANZI
Amphibians (Fig. 43): The formation of the grey crescent, which
appears after fertilization, is related to movements of the egg cortex.
These movements induce a local centre of high metabolism shown by
Child (1943) which is dependent on the maintenance of a high respiratory rate (Lovtrup, 1958). This centre seems to correspond, from a
Interpretation
FIG. 43. Effects of different experimental conditions on explants of amphibian embryos
and tentative interpretation of the determination processes.
physiological point of view, to the animal pole of the sea urchin (Ranzi,
1953) and we can imagine it as a centre of protein denaturation. Consequently notochord determination and neural induction are effects of
protein denaturation. The experiments leading to this conclusion are
summarized in Fig. 43 which shows that protein denaturation produces
notochord determination or nervous system induction and protein
stabilization induces transformation of notochord rudiments into
somites.
SILVIO RANZI
Amphibians (Fig. 43): The formation of the grey crescent, which
appears after fertilization, is related to movements of the egg cortex.
These movements induce a local centre of high metabolism shown by
Child (1943) which is dependent on the maintenance of a high respiratory rate (Lovtrup, 1958). This centre seems to correspond, from a
Interpretation
FIG. 43. Effects of different experimental conditions on explants of amphibian embryos
and tentative interpretation of the determination processes.
physiological point of view, to the animal pole of the sea urchin (Ranzi,
1953) and we can imagine it as a centre of protein denaturation. Consequently notochord determination and neural induction are effects of
protein denaturation. The experiments leading to this conclusion are
summarized in Fig. 43 which shows that protein denaturation produces
notochord determination or nervous system induction and protein
stabilization induces transformation of notochord rudiments into
somites.