PROTEINS IN DEVELOPMENT
231
Storari Offer (1946). These alterations involve an increase in hindbrain
dimensions, the formation of ganglia from the roof of the hindbrain,
duplication of the epiphysis, the hyperdevelopment of lateral line organs,
the formation of epithelial vesicles from the epidermis, and abnormal
FIG. 20. Section of urea-treated ventral explants of young gastrula of Rana. c: notochord; 1: lentoid (from Leone, 1952).
proliferation of epidermis. Rana esculenta embryos treated with IB A
show the same kinds of alteration.
Whether the alterations in the nervous system are induced by the
enlargement of the notochord or by an excess of active evocating substances is a problem which seems to be solved by the presence of nervous rudiments in axolotl ventral explants treated with NaSCN (Ranzi
and Tamini, 1940). In this instance the notochord rudiment is absent
and evocating substances must originate from materials other than the
normal. The paper of Holtfreter (1944), showing that by the action of
several substances and physical agents the same results may be obtained,
supports the interpretation of the liberation of evocating substances
from abnormal materials.
Vegetalizing and animalizing substances induce changes in the initial
determination of many animals. Petromyzon, chick, ascidian, cephalopod, and gasteropod eggs or embryos treated with NaSCN or LiCl
develop peculiar malformations. Elsewhere, I have already summarized
and compared these data (Ranzi, 1957).
B. Differences in Proteins from Embryos
Showing Different Malformations
Research carried out in our laboratory many years ago showed that
ions inducing colloid precipitation induce sea urchin vegetalization
(Tamini, 1943b) and amphibian cyclopic monsters (Tamini, 1943a).
Vice-versa, swelling ions induce sea urchin animalization and the enlargement of the amphibian notochord (Ranzi, 1942). When the various
231
Storari Offer (1946). These alterations involve an increase in hindbrain
dimensions, the formation of ganglia from the roof of the hindbrain,
duplication of the epiphysis, the hyperdevelopment of lateral line organs,
the formation of epithelial vesicles from the epidermis, and abnormal
FIG. 20. Section of urea-treated ventral explants of young gastrula of Rana. c: notochord; 1: lentoid (from Leone, 1952).
proliferation of epidermis. Rana esculenta embryos treated with IB A
show the same kinds of alteration.
Whether the alterations in the nervous system are induced by the
enlargement of the notochord or by an excess of active evocating substances is a problem which seems to be solved by the presence of nervous rudiments in axolotl ventral explants treated with NaSCN (Ranzi
and Tamini, 1940). In this instance the notochord rudiment is absent
and evocating substances must originate from materials other than the
normal. The paper of Holtfreter (1944), showing that by the action of
several substances and physical agents the same results may be obtained,
supports the interpretation of the liberation of evocating substances
from abnormal materials.
Vegetalizing and animalizing substances induce changes in the initial
determination of many animals. Petromyzon, chick, ascidian, cephalopod, and gasteropod eggs or embryos treated with NaSCN or LiCl
develop peculiar malformations. Elsewhere, I have already summarized
and compared these data (Ranzi, 1957).
B. Differences in Proteins from Embryos
Showing Different Malformations
Research carried out in our laboratory many years ago showed that
ions inducing colloid precipitation induce sea urchin vegetalization
(Tamini, 1943b) and amphibian cyclopic monsters (Tamini, 1943a).
Vice-versa, swelling ions induce sea urchin animalization and the enlargement of the amphibian notochord (Ranzi, 1942). When the various