ANIMALIZATION AND VEGETALIZATION
165
facts suggest that lithium ions may be able to interfere with potassium
distribution in the egg. Potassium ions are closely associated with the
metabolism of glucides and they participate in transphosphorylation
reactions (Pressman and Lardy, 1955; Gamble, 1957). Numerous
enzymes are activated by potassium. ATP-phosphopyruvic transphosphorylase, an enzyme functioning in glycolysis, requires the
presence of potassium ions. A study of the enzymatic systems whose
activity depends upon potassium ions should give some useful indications
as to the mode of action of lithium.
C. Animalization
The animalizing effects of sodium, thiocyanate and iodide are only
obtained in aerobiosis. Cyanide or partial anaerobiosis suppresses the
animalizing action of these agents (Lindahl, 1936).
The stimulation of oxidation favours animalization. Pyocyanine
increases oxidation and enhances the animalizing effects of thiocyanate
(Runnström and Thörnblom, 1938). According to Tamini (1941),
methylene blue and p-nitrophenol animalize the sea urchin egg.
Some substrates of carbohydrate catabolism favour animalization.
Glucose exerts a radializing action on the sand-dollar egg (Rulon, 1952b).
Hörstadius (1959) has shown that glucose and different mono- and
disaccharides enhance the animalization of isolated animal halves and
favour the development of the ectodermal structures in whole eggs.
These effects are obtained only with rather strong concentrations of
sugars. Sodium pyruvate has an animalizing effect (Hörstadius and
Strömberg, 1940). Moreover, this agent seems able to act as an animalizing agent in weak concentrations, and as a vegetalizing agent in strong
concentrations (Arosio et al., 1949). Propanediol phosphate, phosphogluconic acid and lactate tend to cause the animalization of isolated
animal halves (Hörstadius and Gustafson, 1947). The need for oxygen,
the favourable action caused by the stimulation of oxidation, and the
animalizing influence of the substrates of carbohydrate catabolism
suggest that animalization is related to the processes of oxidation and
more particularly with carbohydrate catabolism.
The study of the different stages of carbohydrate catabolism during
animalization is only just beginning and information is still rare and
very incomplete.
Horowitz (1940) has studied the respiration of permanent blastulae
obtained by the action of thiocyanate. The respiratory rate of the
treated eggs does not rise above the level characteristic of normal
blastulae. Bäckström (1955), using iodosobenzoic acid as an animalizing
agent, notes that the inhibition of respiration, weak during cleavage,
rises afterwards, especially after hatching. Thus inhibition of respiration
F2
165
facts suggest that lithium ions may be able to interfere with potassium
distribution in the egg. Potassium ions are closely associated with the
metabolism of glucides and they participate in transphosphorylation
reactions (Pressman and Lardy, 1955; Gamble, 1957). Numerous
enzymes are activated by potassium. ATP-phosphopyruvic transphosphorylase, an enzyme functioning in glycolysis, requires the
presence of potassium ions. A study of the enzymatic systems whose
activity depends upon potassium ions should give some useful indications
as to the mode of action of lithium.
C. Animalization
The animalizing effects of sodium, thiocyanate and iodide are only
obtained in aerobiosis. Cyanide or partial anaerobiosis suppresses the
animalizing action of these agents (Lindahl, 1936).
The stimulation of oxidation favours animalization. Pyocyanine
increases oxidation and enhances the animalizing effects of thiocyanate
(Runnström and Thörnblom, 1938). According to Tamini (1941),
methylene blue and p-nitrophenol animalize the sea urchin egg.
Some substrates of carbohydrate catabolism favour animalization.
Glucose exerts a radializing action on the sand-dollar egg (Rulon, 1952b).
Hörstadius (1959) has shown that glucose and different mono- and
disaccharides enhance the animalization of isolated animal halves and
favour the development of the ectodermal structures in whole eggs.
These effects are obtained only with rather strong concentrations of
sugars. Sodium pyruvate has an animalizing effect (Hörstadius and
Strömberg, 1940). Moreover, this agent seems able to act as an animalizing agent in weak concentrations, and as a vegetalizing agent in strong
concentrations (Arosio et al., 1949). Propanediol phosphate, phosphogluconic acid and lactate tend to cause the animalization of isolated
animal halves (Hörstadius and Gustafson, 1947). The need for oxygen,
the favourable action caused by the stimulation of oxidation, and the
animalizing influence of the substrates of carbohydrate catabolism
suggest that animalization is related to the processes of oxidation and
more particularly with carbohydrate catabolism.
The study of the different stages of carbohydrate catabolism during
animalization is only just beginning and information is still rare and
very incomplete.
Horowitz (1940) has studied the respiration of permanent blastulae
obtained by the action of thiocyanate. The respiratory rate of the
treated eggs does not rise above the level characteristic of normal
blastulae. Bäckström (1955), using iodosobenzoic acid as an animalizing
agent, notes that the inhibition of respiration, weak during cleavage,
rises afterwards, especially after hatching. Thus inhibition of respiration
F2