Carp oogenesis and the environment
111
Stage I. Oogonia of different sizes; most are in mitosis. 00gonium diameter:
8—12 um;
nucleus diameter:
6—8 Um.
Stage II. Primary oocytes still have only one nucleolus in the nucleus. Oocyte
diameter:
12—40 Um; nucleus diameter:
10—12 um.
Stage III. Growing oocytes diminate. The number of nucleoli in the nucleus
begins to increase. Lampbrush chromosonæs observed in the nucleus. Oocytes
diameter: 40—200 um; nucleus diameter: 12—17 um.
Stage
row
of vacuoles
appears
on
the periphery of the oocyte cytoplasm.
Later, the vacuoles divide into sheaths. Oocyte diameter: ZOO—300 um; nucleus
diameter:
80—150 um.
-
Stage IVb. The vacuoles increase in size and constitute several layers on the
cell periphery. The first round yolk particles containing lipoprotein appear
in the perinuclear cytoplasm… Oocyte diameter: 300—350 um; nucleus diameter:
150—180 Um.
Stage V. Vacuole size reaches a maximum and the vacuoles almost completely
fill the cytoplasm. A few yolk particles are scattered among the vacuoles,
driving them towards the periphery. Oocyte diameter: 350—600 um; nucleus diame—
ter:
150—200 Um.
Stage VI. The vacuoles are arranged in two to three rows throughout the cyto—
plasm together with the growing yolk particles. The nucleus is still in the
center
of the oocyte and contains many nucleoli attached to the cell membrane.
Oocyte diameter: 600—900 um; nucleus diameter: ISO—200 um.
Stage VIIa. The oocyte and the yolk particles hardly grow any more. Moving
away from the nuclear membrane, the nucleoli migrate to the center. Sometimes
the nucleus begins to move towards the micropyle that is already present.
Oocyte diameter: 900—1000 um; nucleus diameter: 200 um.
Stage VIIb. The nucleus is on the periphery of the oocyte, immediately under
the micropyle. All the nucleoli are concentrated in the center of the nucleus.
Neither the oocyte nor the nucleus increases any more.
Stage VIIe. Vitellogenesis is completed in the oocytes; the nuclear membrane
and the nucleoli have been eliminated. Near the micropyle, in the cytoplasm
Of the animal pole, the chromosomes are in an early metaphase of the first
ripening distribution. As a result of hydration, the oocytes increase to about
1200 um in diameter.
Bieniarz and Epler (1976) have reported a simple, rapid method for stur
dying the nuclear processes occurring before and during ovulation. A piece of
ovary obtained by biopsy or dissection is placed in Serra fixative. Then, the
CYt0plasm becomes transparent in a few minutes and the site of the nucleus lS
easy to see. As ovulation progresses,
the nuclear membrane is elinunated
and
the whole oocyte is hydrated, and the oocyte nucleus cannot be
any longer in the Serra fixative.
_
‘
THE DYNAMICS OF OOGENESIS IN NATURAL CONDITIONS
Figures for oogenesis observed during ontogeny are shown using
the data
of a 7—Year experiment (Horvath, 1985) (Tabl. 1). There are con81derable
ferences in the developmental stage of the ovary and oocyte in carp of identi—
age and from the same population. Irichimovich and Zelenin (1959) empha—
that great discrepancies are found in populations of third—summer fish
W1th a quicker increase in weight. This is the stage when yolk accumulation
111
Stage I. Oogonia of different sizes; most are in mitosis. 00gonium diameter:
8—12 um;
nucleus diameter:
6—8 Um.
Stage II. Primary oocytes still have only one nucleolus in the nucleus. Oocyte
diameter:
12—40 Um; nucleus diameter:
10—12 um.
Stage III. Growing oocytes diminate. The number of nucleoli in the nucleus
begins to increase. Lampbrush chromosonæs observed in the nucleus. Oocytes
diameter: 40—200 um; nucleus diameter: 12—17 um.
Stage
row
of vacuoles
appears
on
the periphery of the oocyte cytoplasm.
Later, the vacuoles divide into sheaths. Oocyte diameter: ZOO—300 um; nucleus
diameter:
80—150 um.
-
Stage IVb. The vacuoles increase in size and constitute several layers on the
cell periphery. The first round yolk particles containing lipoprotein appear
in the perinuclear cytoplasm… Oocyte diameter: 300—350 um; nucleus diameter:
150—180 Um.
Stage V. Vacuole size reaches a maximum and the vacuoles almost completely
fill the cytoplasm. A few yolk particles are scattered among the vacuoles,
driving them towards the periphery. Oocyte diameter: 350—600 um; nucleus diame—
ter:
150—200 Um.
Stage VI. The vacuoles are arranged in two to three rows throughout the cyto—
plasm together with the growing yolk particles. The nucleus is still in the
center
of the oocyte and contains many nucleoli attached to the cell membrane.
Oocyte diameter: 600—900 um; nucleus diameter: ISO—200 um.
Stage VIIa. The oocyte and the yolk particles hardly grow any more. Moving
away from the nuclear membrane, the nucleoli migrate to the center. Sometimes
the nucleus begins to move towards the micropyle that is already present.
Oocyte diameter: 900—1000 um; nucleus diameter: 200 um.
Stage VIIb. The nucleus is on the periphery of the oocyte, immediately under
the micropyle. All the nucleoli are concentrated in the center of the nucleus.
Neither the oocyte nor the nucleus increases any more.
Stage VIIe. Vitellogenesis is completed in the oocytes; the nuclear membrane
and the nucleoli have been eliminated. Near the micropyle, in the cytoplasm
Of the animal pole, the chromosomes are in an early metaphase of the first
ripening distribution. As a result of hydration, the oocytes increase to about
1200 um in diameter.
Bieniarz and Epler (1976) have reported a simple, rapid method for stur
dying the nuclear processes occurring before and during ovulation. A piece of
ovary obtained by biopsy or dissection is placed in Serra fixative. Then, the
CYt0plasm becomes transparent in a few minutes and the site of the nucleus lS
easy to see. As ovulation progresses,
the nuclear membrane is elinunated
and
the whole oocyte is hydrated, and the oocyte nucleus cannot be
any longer in the Serra fixative.
_
‘
THE DYNAMICS OF OOGENESIS IN NATURAL CONDITIONS
Figures for oogenesis observed during ontogeny are shown using
the data
of a 7—Year experiment (Horvath, 1985) (Tabl. 1). There are con81derable
ferences in the developmental stage of the ovary and oocyte in carp of identi—
age and from the same population. Irichimovich and Zelenin (1959) empha—
that great discrepancies are found in populations of third—summer fish
W1th a quicker increase in weight. This is the stage when yolk accumulation