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SAUL WISCHNITZER
involved in the formation of this organelle. After its organization, the yolk
nucleus gradually moves toward the periphery of the oocyte and gives off
small numbers of mitochondria along the way. Finally, the remaining
mitochondria become distributed in the peripheral cytoplasm.
3. The Golgi complex is present in linear, arc, and C-shaped formations.
Prior to yolk formation, each mass of Golgi mass consists primarily of a
cluster of vesicles; during yolk formation, each mass consists of several
cisternae.
4. Annulate lamellae are present as isolated sheets or as complex systems
of membranes. Each lamella, apparently, is formed by blebbing of rows of
vesicles from the nuclear envelope. As the vesicles undergo fusion to form
cisternae, the rows of vesicles become organized into groups. The annulate
lamellae, when thus organized, move toward the periphery and apparently
are broken up there into vesicles at that site. The function of this apparently
transient organelle is obscure.
5. The oocyte cytoplasm contains numerous optically empty vesicles
ranging in size up to 200 ιημ in diameter. These may be derived by blebbing
from the nuclear envelope, by becoming detached from the annulate lamellae, or arising by micropinocytosis from the plasmalemma. An organized
endoplasmic reticulum is absent in developing oocytes.
6. Cytosomes, which are vesicles containing dense material, are reportedly present in the cytoplasm. Similar bodies called chromidia have
also been seen, and these presumably are of nuclear origin. These two types
of structures, as well as small vesicles from the Golgi and mitochondria,
have been postulated to become organized into complex cytosomes in
certain forms.
7. Yolk platelets are the most prominent inclusion bodies found in
the cytoplasm. Each consists of a dense, crystalline core, a granular cortex,
and an outer membrane. The method of formation of the yolk platelets
varies in different species, with intramitochondrial deposition of yolk
occurring most frequently. It has been suggested that platelets also are
derivatives of multivesicular bodies as well as of complex cytosomes.
8. Lipochondria are irregularly shaped bodies having a homogeneous
consistency. They are the first type of inclusion body to form and appear
initially as clusters. Later they multiply and form a peripheral ring which
migrates inward to break up and be distributed throughout the cytoplasm.
Their mode of formaton is not clear.
9. Cortical granules apparently are present only in anurans. They
appear to be formed from the small vesicles of the Golgi complex which
are peripherally located. The granules disappear during fertilization and
reportedly are broken up into the fine material present in the perivitelline
space.
SAUL WISCHNITZER
involved in the formation of this organelle. After its organization, the yolk
nucleus gradually moves toward the periphery of the oocyte and gives off
small numbers of mitochondria along the way. Finally, the remaining
mitochondria become distributed in the peripheral cytoplasm.
3. The Golgi complex is present in linear, arc, and C-shaped formations.
Prior to yolk formation, each mass of Golgi mass consists primarily of a
cluster of vesicles; during yolk formation, each mass consists of several
cisternae.
4. Annulate lamellae are present as isolated sheets or as complex systems
of membranes. Each lamella, apparently, is formed by blebbing of rows of
vesicles from the nuclear envelope. As the vesicles undergo fusion to form
cisternae, the rows of vesicles become organized into groups. The annulate
lamellae, when thus organized, move toward the periphery and apparently
are broken up there into vesicles at that site. The function of this apparently
transient organelle is obscure.
5. The oocyte cytoplasm contains numerous optically empty vesicles
ranging in size up to 200 ιημ in diameter. These may be derived by blebbing
from the nuclear envelope, by becoming detached from the annulate lamellae, or arising by micropinocytosis from the plasmalemma. An organized
endoplasmic reticulum is absent in developing oocytes.
6. Cytosomes, which are vesicles containing dense material, are reportedly present in the cytoplasm. Similar bodies called chromidia have
also been seen, and these presumably are of nuclear origin. These two types
of structures, as well as small vesicles from the Golgi and mitochondria,
have been postulated to become organized into complex cytosomes in
certain forms.
7. Yolk platelets are the most prominent inclusion bodies found in
the cytoplasm. Each consists of a dense, crystalline core, a granular cortex,
and an outer membrane. The method of formation of the yolk platelets
varies in different species, with intramitochondrial deposition of yolk
occurring most frequently. It has been suggested that platelets also are
derivatives of multivesicular bodies as well as of complex cytosomes.
8. Lipochondria are irregularly shaped bodies having a homogeneous
consistency. They are the first type of inclusion body to form and appear
initially as clusters. Later they multiply and form a peripheral ring which
migrates inward to break up and be distributed throughout the cytoplasm.
Their mode of formaton is not clear.
9. Cortical granules apparently are present only in anurans. They
appear to be formed from the small vesicles of the Golgi complex which
are peripherally located. The granules disappear during fertilization and
reportedly are broken up into the fine material present in the perivitelline
space.