ANALYSIS OF A HERTWIG EFFECT INDUCED BY THE IRRADIATION OF RANA PIPIENS SPERM WITH ULTRAVIOLET

In an attempt to examine genomic function of the oocyte nucleus during meiotic maturation, the effects of X-irradiation on the oocyte of the frog (Rana pipiens) were studied. When oocytes were irradiated with 6000–36000 R before initiation of maturation, the ovulated eggs frequently failed to be fertilized and the jelly surrounding the unfertilizable eggs was always damaged. However, the egg itself proved to retain the capability of cleaving when a nucleus was transplanted from a blastula. Also, X-irradiated eggs when invested with the jelly from unirradiated frogs recovered their capacity for fertilization. The eggs thus fertilized developed and exhibited abnormalities characteristic of X-irradiation such as arrest of gastrulation and neurulation as well as production of haploidy. Irradiation of oocytes after completion of maturation brought about developmental abnormalities more frequently than irradiation before initiation of maturation. The Hertwig effect was found only when oocytes were irradiated after completion of maturation. However, no qualitative differences were found in the developmental abnormalities produced by irradiation before maturation and those produced by irradiation after maturation.

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Comparative Morphology of Intercellular Bridges Between Developing Germ Cells of the Ovary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068631 ◽

1970 ◽

Vol 28 ◽

pp. 328-329

Author(s):

J. R. Ruby ◽

R. F. Dyer ◽

R. G. Skalko ◽

R. F. Gasser ◽

E. P. Volpe

Keyword(s):

Germ Cells ◽

Rana Pipiens ◽

Comparative Morphology ◽

Dense Material ◽

Individual Species ◽

Microscope Examination ◽

Electron Dense Material ◽

Intercellular Bridges ◽

Cytoplasmic Side ◽

Intercellular Connections

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.

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The application of video-enhanced constrast/differential interference constrast microscopy in conjunction with whole mount electron microscopy to the study of organelle transport

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102419 ◽

1988 ◽

Vol 46 ◽

pp. 66-67

Author(s):

J. H. Hayden

Keyword(s):

Electron Microscopy ◽

Rana Pipiens ◽

Silver Film ◽

Immunofluorescence Microscopy ◽

Organelle Transport ◽

Linear Element ◽

Whole Mount ◽

Carbon Coated ◽

Linear Elements ◽

Dic Microscopy

In a previous study, Allen video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with immunofluorescence microscopy to demonstrate that organelles and vesicle move in either direction along linear elements composed of microtubules. However, this study was limited in that the number of microtubules making up a linear element could not be determined. To overcome this limitation, we have used AVEC-DIC microscopy in conjunction with whole mount electron microscopy.Keratocytes from Rana pipiens were grown on glass coverslips as described elsewhere. Gold London Finder grids were Formvar- and carbon coated, and sterilized by exposure to ultraviolet light. It is important to select a Formvar film that gives a grey reflection when it is floated on water. A silver film is too thick and will detract from the image in the light microscope.

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