The Ultrastructure of the Cytoplasm of the Developing Amphibian Egg

Wischnitzer, Saul

doi:10.1016/b978-1-4831-9952-8.50008-0

Cited by 83 publications

(34 citation statements)

References 59 publications

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“…They give two reasons: (a) from kinetic studies they claim that 15 % of oocyte Na lies in reality in the follicular cell layer on the surface of the oocyte; (b) an Na-sensitive glass micro-electrode detected 79 % of the total Na in the oocyte (or 94 % if it is supposed that 15 % of Na is in the follicle cells). Morrill (Wischnitzer, 1966) (Dick & Lea, 1964, 1967Dick & Fry, 1975) in smaller cells (800-1000 tm diameter) of much lower Na concentration obtained from animals kept at room temperature similar to those used in the present experiments. Even if the data of Morrill et al were reliable (which seems unlikely), the comparison which they make would not be valid.…”

Section: Discussionmentioning

confidence: 83%

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

Dick¹

1978

The Journal of Physiology

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Section: Discussionmentioning

confidence: 83%

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

Dick¹

1978

The Journal of Physiology

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“…In the literature there exist only very vague data about the duration of specific oogenesis phases in amphibians (e.g., Grant, 1953;Wischnitzer, 1966). According to Gall and Callan (1962) and Callan (1963) the lampbrush stage in Triturus cristatus takes about 7 moo The same period lasts ca.…”

Section: Temporal Sequence Of Oocyte Growthmentioning

confidence: 99%

“…Yolk platelets and ribosomes are the two quantitatively dominant products which are stored in the growing oocyte (for an extensive review see Wischnitzer, 1966) . While the yolk protein is synthesized in the liver and selectively taken up by the oocytes from the circulation as a Ca-lipophosphoprotein complex (e.g., Wallace and Dumont, 1968;Wallace and Jared, 1969;Jared and Wallace, 1970;Wallace, 1970), there is no indication for extraoocyte production of RNA and subsequent transfer to the oocyte in amphibians (Brown, 1966; see also Panje and Kessel, 1968).…”

Section: Introductionmentioning

confidence: 99%

Nuclear pore flow rate of ribosomal RNA and chain growth rate of its precursor during oogenesis of Xenopus laevis

Scheer

1973

Developmental Biology

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The numb er of ribosomal RNA mol ecules which are transferred through an average nuclear pore complex per minute into the cytoplasm (nuclear pore flow rate, NPFR) during oocyte growth of Xenopus laevis is estimated. The NPFR calculations are based on determinations of the increase of cytoplasm ic rRNA conten t during defined time intervals and of the total number of pore complexes in the respective oogenesis stages. In the mid-la mpbrush stage (500:"700 I'm oocyte diameter) the NPFR is maximal with 2.62 rRNA molecules/ pore/ minute. Then it decreases to zero at the end of oogenesis. The nucleocytoplasmic RNA f10w rates determined are compared with corresponding va lues of other cell types. The molecular weight of the rRNA precursor transcribed in t he extrachromosomal nucleoli of Xenopus la mpbrush stage oocytes is determined by acrylamide ge l electrophoresis to be 2.5 x 10· daltons. From the temporal increase of cytoplasmic rRNA (3.8 I'g per oocyte in 38 days) and the known number of simultaneously grow ing precursor molecules in the nucleus the chain growth rate of the 40 S precursor RNA is estimated to be 34 nucleotides per second.

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“…Although they and others (20,21) The effect of progesterone stimulation (2 y/ml) on the rate of in vitro incorporation of leucine-3H into purified total protein of OTMO mentioned the outer coverings of the follicle, primary emphasis has been placed on the relations between the follicular epithelium and the developing oocyte . Accordingly, we shall describe in some detail the ultrastructure of the normal, unstimulated follicle envelopes.…”

Section: Effects Of Hormonal Stimulation and Of Antibiotic Treatmentmentioning

confidence: 99%

Metabolic and Ultrastructural Changes in the Frog Ovarian Follicle in Response to Pituitary Stimulation

Anderson

Yatvin

1970

The Journal of Cell Biology

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Frog ovarian fragments were prevented from ovulating in vitro by the addition of actinomycin D up to 3 hr following pituitary stimulation ; but addition of Actinomycin D 6 hr after stimulation was far less effective . Puromycin, on the other hand, effectively inhibited ovulation when added as late as 6 hr after pituitary stimulation . Although actinomycin D reduced uptake of uridine-3H, and puromycin reduced uptake of leucine 8H and lysine-14C by pituitary-stimulated ovarian tissue minus oocytes (OTMO) in vitro, it was found that pituitary stimulation did not significantly increase uptake of these compounds by OTMO . Radioautographs of ovarian follicles fixed 6 hr after the addition of pituitary extract and uridine sH in vitro revealed increased RNA synthesis in the peritoneal surface epithelium, compared with unstimulated controls, while the ovarian sac epithelium showed no increase . Gross ultrastructural changes occurred in the peritoneal area of ovarian follicles following pituitary stimulation in vivo, including loss of collagen fibrils, and general disorganization of the connective tissue theca . Changes in the rough endoplasmic reticulum of the peritoneal epithelial cells, while frequently encountered, were less pronounced . None of these changes was observed in the ovarian sac area, or in the interfollicular region . The above data are consistent with the hypothesis that pituitary stimulation of the frog ovary results in increased synthesis of RNA and protein by the peritoneal epithelial cells, and that the protein may be collagenase .

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The Ultrastructure of the Cytoplasm of the Developing Amphibian Egg

Cited by 83 publications

References 59 publications

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

Nuclear pore flow rate of ribosomal RNA and chain growth rate of its precursor during oogenesis of Xenopus laevis

Metabolic and Ultrastructural Changes in the Frog Ovarian Follicle in Response to Pituitary Stimulation

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