PROTEINS IN DEVELOPMENT
253
J. Conclusion
All this evidence seems to show that animalization and vegetalization
originates from the enlargement or inhibition of the areas in which a
process of protein denaturation, necessary for new protein synthesis, is
acting. I think that the following tentative interpretation of development may be formulated.
Sea urchins (Fig. 42): Fertilization, by activating certain enzymic
systems, according to the data of the school of Runnström (1949),
FIG. 42. Tentative interpretation of the behaviour of protein molecules, represented
by helixes, during normal development of sea urchins and under experimental conditions.
activates a higher metabolism at the animal pole, where there are more
easily digested proteins. Bearing in mind the fact that several metabolites are animalizing substances, the activation of the enzymes and
subsequent formation of metabolites occurring at the animal pole seem
to lead to the development of the animal hemisphere, while the vegetative pole is stabilized because of failure to form these metabolites. Some
regulative processes are acting: for example pyruvate in low concentration animalizes and in high concentration it vegetalizes. We can tentatively recognize here a phenomenon acting in normal development.
Small amounts of pyruvate formed during animal development lead to
protein denaturation and increase in the animal structures. After a
certain stage in animal development the amount of pyruvate formed
is in excess of that required and vegetal structures are induced. Processes of this kind may be the basis of the animal-vegetative balance.
This balance is changed if artificial animalizing substances such as
NaSCN or vegetalizing substances such as LiCl are allowed to act.
12
A.M. 2
253
J. Conclusion
All this evidence seems to show that animalization and vegetalization
originates from the enlargement or inhibition of the areas in which a
process of protein denaturation, necessary for new protein synthesis, is
acting. I think that the following tentative interpretation of development may be formulated.
Sea urchins (Fig. 42): Fertilization, by activating certain enzymic
systems, according to the data of the school of Runnström (1949),
FIG. 42. Tentative interpretation of the behaviour of protein molecules, represented
by helixes, during normal development of sea urchins and under experimental conditions.
activates a higher metabolism at the animal pole, where there are more
easily digested proteins. Bearing in mind the fact that several metabolites are animalizing substances, the activation of the enzymes and
subsequent formation of metabolites occurring at the animal pole seem
to lead to the development of the animal hemisphere, while the vegetative pole is stabilized because of failure to form these metabolites. Some
regulative processes are acting: for example pyruvate in low concentration animalizes and in high concentration it vegetalizes. We can tentatively recognize here a phenomenon acting in normal development.
Small amounts of pyruvate formed during animal development lead to
protein denaturation and increase in the animal structures. After a
certain stage in animal development the amount of pyruvate formed
is in excess of that required and vegetal structures are induced. Processes of this kind may be the basis of the animal-vegetative balance.
This balance is changed if artificial animalizing substances such as
NaSCN or vegetalizing substances such as LiCl are allowed to act.
12
A.M. 2