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ALBERTO MONROY AND RACHELE MAGGIO
substantial activity. In the course of development the activity of
glutathione decreases while the proteins become labelled (Nakano and
Monroy, 1958b), thus suggesting that this peptide must play some role
as an intermediary product for the synthesis of the embryonic proteins.
The observations on the development of Oryzias previously mentioned
(Monroy etal., 1961a), certainly indicate that some peptide may be an
obligatory intermediate step between the high molecular yolk and the
embryonic proteins. However, all this does not add to our knowledge of
the actual mechanisms and pathways of yolk utilization.
E. The Pigment Granules
In most sea urchins, the eggs contain a certain amount of pigment
granules of unknown function. In the eggs of Paracentrotus the pigment
granules have been isolated in what seems a condition of relative purity
(Monroy and De Nicola, 1952) and proved to consist of carotenoids
attached to protein(s) with a fairly high carbohydrate content (8-5% of
the dry weight) which is suggestive of a metabolic function. Electrophoretic analysis and salting-out fractionation indicated the presence of
three components. The puzzling observation was also made that, though
the preparations from unfertilized eggs proved to be free of nucleic acid,
those from mesenchyme blastulae and older stages always contained
some nucleic acid which appeared in quite constant amounts in the
different preparations. Should it be possible to show that this is not a
contamination, the observation would certainly be of interest. Whether
the pigment granules are somehow involved in the life-cycle of the
mitochondria (Gustafson, 1954) is at present unknown. It is not even
known whether the pigment granules are all alike in their chemical
constitution. Recently there has been the interesting suggestion (Nass,
1962) that the enzyme phosphoprotein phosphatase, which is important
for the utilization of yolk, is contained, in the amphibian egg, in the
pigment granules. This is actually the first evidence that pigment
granules may participate in the metabolism of the embryo. The pigment
of Paracentrotus and of other sea urchin eggs is a complex mixture of
several carotenoids (De Nicola and Monroy-Oddo, 1952; De Nicola and
Goodwin, 1954). Among them two yet unidentified types—named
Paracentrotin A and Β—were described. The interesting, although
unexplained result, is that these two pigments are missing in the testes
which raises the problem of their possible function in the metabolism of
the egg. However, no quantitative changes of the Paracentrotins were
found in the course of early development (De Nicola and Goodwin, 1954)
which may suggest either a non-utilization or an equilibrium between
utilization and neoformation. On the other hand, a general decrease in
the total pigments has been found to occur between fertilization and the
ALBERTO MONROY AND RACHELE MAGGIO
substantial activity. In the course of development the activity of
glutathione decreases while the proteins become labelled (Nakano and
Monroy, 1958b), thus suggesting that this peptide must play some role
as an intermediary product for the synthesis of the embryonic proteins.
The observations on the development of Oryzias previously mentioned
(Monroy etal., 1961a), certainly indicate that some peptide may be an
obligatory intermediate step between the high molecular yolk and the
embryonic proteins. However, all this does not add to our knowledge of
the actual mechanisms and pathways of yolk utilization.
E. The Pigment Granules
In most sea urchins, the eggs contain a certain amount of pigment
granules of unknown function. In the eggs of Paracentrotus the pigment
granules have been isolated in what seems a condition of relative purity
(Monroy and De Nicola, 1952) and proved to consist of carotenoids
attached to protein(s) with a fairly high carbohydrate content (8-5% of
the dry weight) which is suggestive of a metabolic function. Electrophoretic analysis and salting-out fractionation indicated the presence of
three components. The puzzling observation was also made that, though
the preparations from unfertilized eggs proved to be free of nucleic acid,
those from mesenchyme blastulae and older stages always contained
some nucleic acid which appeared in quite constant amounts in the
different preparations. Should it be possible to show that this is not a
contamination, the observation would certainly be of interest. Whether
the pigment granules are somehow involved in the life-cycle of the
mitochondria (Gustafson, 1954) is at present unknown. It is not even
known whether the pigment granules are all alike in their chemical
constitution. Recently there has been the interesting suggestion (Nass,
1962) that the enzyme phosphoprotein phosphatase, which is important
for the utilization of yolk, is contained, in the amphibian egg, in the
pigment granules. This is actually the first evidence that pigment
granules may participate in the metabolism of the embryo. The pigment
of Paracentrotus and of other sea urchin eggs is a complex mixture of
several carotenoids (De Nicola and Monroy-Oddo, 1952; De Nicola and
Goodwin, 1954). Among them two yet unidentified types—named
Paracentrotin A and Β—were described. The interesting, although
unexplained result, is that these two pigments are missing in the testes
which raises the problem of their possible function in the metabolism of
the egg. However, no quantitative changes of the Paracentrotins were
found in the course of early development (De Nicola and Goodwin, 1954)
which may suggest either a non-utilization or an equilibrium between
utilization and neoformation. On the other hand, a general decrease in
the total pigments has been found to occur between fertilization and the