A fine structural study of the formation of temporary swellings (Herring bodies) and reversible degeneration of neurosecretory axons following microiontophoretic ejection of vinblastine into the hypothalamo-neurohypophysial tract of the frog (Rana pipiens)

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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An Ultra-Structural Study of Human Melanoma in Vivo and Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091275 ◽

1976 ◽

Vol 34 ◽

pp. 258-259

Author(s):

James R. Gaylor ◽

Fredda Schafer ◽

Robert E. Nordquist

Keyword(s):

Endoplasmic Reticulum ◽

Golgi Apparatus ◽

Protein Aggregation ◽

Structural Study ◽

Human Melanoma ◽

Protein Matrix ◽

Early Form ◽

Endoplasmic Reticulum Protein ◽

Mitochondrial Origin

Several theories on the origin of the melanosome exist. These include the Golgi origin theory, in which a tyrosinase-rich protein is "packaged" by the Golgi apparatus, thus forming the early form of the melanosome. A second theory postulates a mitochondrial origin of melanosomes. Its author contends that the melanosome is a modified mitochondria which acquires melanin during its development. A third theory states that a pre-melanosome is formed in the smooth or rough endoplasmic reticulum. Protein aggregation is suggested by one author as a possible source of the melanosome. This fourth theory postulates that the melanosome originates when the protein products of several genetic loci aggregate in the cytoplasm of the melanocyte. It is this protein matrix on which the melanin is deposited. It was with these theories in mind that this project was undertaken.

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