ANIMALIZATION AND VEGETALIZATION
169
different parts of the embryo is possible. The formation of new proteins
during development has been analysed by various methods. The study
of soluble specific proteins by Abderhalden^ protective enzyme test has
shown that changes in protein specificity are most marked at the stage
of primary mesenchyme formation (Ishida and Yasumasu, 1957).
With immunological methods, Perlmann and Gustafson (1948),
Perlmann (1953), and Perlmann and Couffer-Kaltenbach (1957) have
observed that the unfertilized eggs and the first stages of development
have practically the same antigens, which show quantitative
fluctuations
during development. New soluble antigens have been detected in the
pluteus stage. The antigenic constitution of larvae vegetalized by
lithium does not differ from that of normal larvae. The antigens of
animalized larvae have not yet been studied.
This research has provided a useful indication of protein metabolism
during normal development. Their extension to the study of animalized
and vegetalized embryos should suggest the precise relationship existing
between protein metabolism on the one hand and animalization and
vegetalization on the other. These problems have been approached in an
indirect manner by the study of the effects of amino-acids and of their
analogues on the development. The analogues of amino-acids present a
possible means of interfering with amino-acids and protein metabolism.
Gustafson and Hörstadius (1957) have examined the effects of various
amino-acids on the isolated animal halves. Indeed, the latter prove more
sensitive to the experimental modification of determination than the
whole egg. L-Glutamine and L-lysine exert a clear animalizing effect ; the
other amino-acids studied exert either weak or no vegetalizing effects.
The results obtained are, on the whole, not very consistent. Moreover,
they vary with the species of the sea urchin used. Recently Fudge (1959)
has shown that tyrosine isomers produce consistent vegetalization both
of whole eggs and of animal and vegetal halves. Respiration is inhibited
by tyrosine, but contrary to lithium, this inhibition does not affect the
exponential increase of the respiration. The action of tyrosine on respiration, therefore, is unlike that of lithium. Gustafson and Hörstadius
(1955) have also examined the effects of several structural analogues of
amino-acids. Their experiments were undertaken on isolated animal
halves and on whole eggs treated with lithium. Except for an analogue
of the arginine, canavanine, which was animalizing, all the other
analogues studied had vegetalizing effects. This is true in the case of
allyglycine, an analogue of cysteine, of DL-ß-phenyllactic acid and of
j8-2-thienylalanine, both analogues of the phenylalanine, of D-leucine, an
analogue of leucine, of ethionine and of DL-norleucine, both analogues of
methionine. Bosco and Monroy (1960) have observed that short treatments with ethionine inhibit the differentiation of the primary mesen-
169
different parts of the embryo is possible. The formation of new proteins
during development has been analysed by various methods. The study
of soluble specific proteins by Abderhalden^ protective enzyme test has
shown that changes in protein specificity are most marked at the stage
of primary mesenchyme formation (Ishida and Yasumasu, 1957).
With immunological methods, Perlmann and Gustafson (1948),
Perlmann (1953), and Perlmann and Couffer-Kaltenbach (1957) have
observed that the unfertilized eggs and the first stages of development
have practically the same antigens, which show quantitative
fluctuations
during development. New soluble antigens have been detected in the
pluteus stage. The antigenic constitution of larvae vegetalized by
lithium does not differ from that of normal larvae. The antigens of
animalized larvae have not yet been studied.
This research has provided a useful indication of protein metabolism
during normal development. Their extension to the study of animalized
and vegetalized embryos should suggest the precise relationship existing
between protein metabolism on the one hand and animalization and
vegetalization on the other. These problems have been approached in an
indirect manner by the study of the effects of amino-acids and of their
analogues on the development. The analogues of amino-acids present a
possible means of interfering with amino-acids and protein metabolism.
Gustafson and Hörstadius (1957) have examined the effects of various
amino-acids on the isolated animal halves. Indeed, the latter prove more
sensitive to the experimental modification of determination than the
whole egg. L-Glutamine and L-lysine exert a clear animalizing effect ; the
other amino-acids studied exert either weak or no vegetalizing effects.
The results obtained are, on the whole, not very consistent. Moreover,
they vary with the species of the sea urchin used. Recently Fudge (1959)
has shown that tyrosine isomers produce consistent vegetalization both
of whole eggs and of animal and vegetal halves. Respiration is inhibited
by tyrosine, but contrary to lithium, this inhibition does not affect the
exponential increase of the respiration. The action of tyrosine on respiration, therefore, is unlike that of lithium. Gustafson and Hörstadius
(1955) have also examined the effects of several structural analogues of
amino-acids. Their experiments were undertaken on isolated animal
halves and on whole eggs treated with lithium. Except for an analogue
of the arginine, canavanine, which was animalizing, all the other
analogues studied had vegetalizing effects. This is true in the case of
allyglycine, an analogue of cysteine, of DL-ß-phenyllactic acid and of
j8-2-thienylalanine, both analogues of the phenylalanine, of D-leucine, an
analogue of leucine, of ethionine and of DL-norleucine, both analogues of
methionine. Bosco and Monroy (1960) have observed that short treatments with ethionine inhibit the differentiation of the primary mesen-