VITELLINE MEMBRANE AND CORTICAL PARTICLES 257
evidence favors the conclusion that masked sulfated polysaccharides
are present within the cytoplasmic region. This is the region where the
cortical particles are found. In the oocytes they probably contain sulfated polysaccharides, intimately bound to proteins or other compounds.
The strong labeling of the cytoplasm with S
3 5 0 4 indicates a rather
rapid synthesis of the masked sulfated polysaccharide. According to
autoradiographic evidence, the corresponding proteins arise mainly
within the nucleus. The question arises whether the ribosomes that undoubtedly (Section I,B,2) are contained in, or connected with, the cortical particles are actively engaged in protein synthesis in situ, or whether
they are merely carriers of protein molecules that are released within or
at the surface of the cortical particles. It follows also from the data presented in Section I,B,2 that the ribosomes are delivered from the nucleus
in the form of composite operational units. Within this also proteins
may be transported. The evidence at hand, however, does not exclude a
continued local protein synthesis. The use of a higher resolution autoradiography will be necessary in further investigation of the matter. The
situation is also complicated by the possibility that conditions may vary
in different steps of development of the oocyte.
In connection with the maturation of the oocytes, the cortical particles
are moving to the egg surface, as described in Section I,B,3. As found by
Immers (1961b), the material incorporating sulfate is simultaneously
displaced in the direction of the egg surface. During the maturation divisions of the oocyte, the S
3 5
0 4 -labeled material has shifted its position
so as to form a layer below the cell surface. In the stage represented in
Immers' Fig. 7 (loc. cit.), its thickness amounts to about one-third of
the egg radius. This egg had probably just passed through the maturation
divisions. The cortical particles resided now, to a large extent, in the outmost cortical layer. A minor number of them probably still remained in
an inner region of the cortex. The autoradiogram, however, strongly
gave the impression that cytoplasm outside the cortical particles becomes labeled by S
3 5 0 4 ; in other words, the sulfated polysaccharides are
not only limited to the cortical particles. In the fully mature egg, the
labeled region was more limited to the outer cortex.
With the migration of the cortical particles to the cortex they also
attain an affinity to certain dyes such as the Hale reagent and Alcian
blue. This affinity to Hale reagent is different in different species; it is
strong in Arbacia, Echinocardium,
and Echinus. In all these species, the
Hale reaction was negative in the oocyte. The change upon maturation
is thus particularly striking. In Paracentrotus
lividus a definite Hale
staining reaction of the surface of the mature eggs occurs, but it is comparatively weak (cf. Immers, 1956, Fig. 1). Alcian blue proved, how-
evidence favors the conclusion that masked sulfated polysaccharides
are present within the cytoplasmic region. This is the region where the
cortical particles are found. In the oocytes they probably contain sulfated polysaccharides, intimately bound to proteins or other compounds.
The strong labeling of the cytoplasm with S
3 5 0 4 indicates a rather
rapid synthesis of the masked sulfated polysaccharide. According to
autoradiographic evidence, the corresponding proteins arise mainly
within the nucleus. The question arises whether the ribosomes that undoubtedly (Section I,B,2) are contained in, or connected with, the cortical particles are actively engaged in protein synthesis in situ, or whether
they are merely carriers of protein molecules that are released within or
at the surface of the cortical particles. It follows also from the data presented in Section I,B,2 that the ribosomes are delivered from the nucleus
in the form of composite operational units. Within this also proteins
may be transported. The evidence at hand, however, does not exclude a
continued local protein synthesis. The use of a higher resolution autoradiography will be necessary in further investigation of the matter. The
situation is also complicated by the possibility that conditions may vary
in different steps of development of the oocyte.
In connection with the maturation of the oocytes, the cortical particles
are moving to the egg surface, as described in Section I,B,3. As found by
Immers (1961b), the material incorporating sulfate is simultaneously
displaced in the direction of the egg surface. During the maturation divisions of the oocyte, the S
3 5
0 4 -labeled material has shifted its position
so as to form a layer below the cell surface. In the stage represented in
Immers' Fig. 7 (loc. cit.), its thickness amounts to about one-third of
the egg radius. This egg had probably just passed through the maturation
divisions. The cortical particles resided now, to a large extent, in the outmost cortical layer. A minor number of them probably still remained in
an inner region of the cortex. The autoradiogram, however, strongly
gave the impression that cytoplasm outside the cortical particles becomes labeled by S
3 5 0 4 ; in other words, the sulfated polysaccharides are
not only limited to the cortical particles. In the fully mature egg, the
labeled region was more limited to the outer cortex.
With the migration of the cortical particles to the cortex they also
attain an affinity to certain dyes such as the Hale reagent and Alcian
blue. This affinity to Hale reagent is different in different species; it is
strong in Arbacia, Echinocardium,
and Echinus. In all these species, the
Hale reaction was negative in the oocyte. The change upon maturation
is thus particularly striking. In Paracentrotus
lividus a definite Hale
staining reaction of the surface of the mature eggs occurs, but it is comparatively weak (cf. Immers, 1956, Fig. 1). Alcian blue proved, how-