Integumentary Pigmentation in the Frog, Rana Pipiens, during Metamorphosis, with Especial Reference to Tail-Skin Histolysis

1929 ◽  
Vol 2 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Verlus F. Lindeman
Keyword(s):  
Rana Pipiens ◽  
Especial Reference

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

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.

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

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.

scholarly journals NUTRITIONAL STUDIES ON THE GROWTH OF FROG LARVÆ (RANA PIPIENS)

1919 ◽  
Vol 38 (2) ◽  
pp. 325-344
Author(s):  
A.D. Emmett ◽  
Floyd P. Allen ◽  
G.O. Luros ◽  
M. Sturtevant
Keyword(s):  
Rana Pipiens ◽  
Nutritional Studies

scholarly journals EFFECTS OF LIGHT ON NORMAL RABBITS, WITH ESPECIAL REFERENCE TO THE ORGANIC REACTION

1926 ◽  
Vol 44 (4) ◽  
pp. 483-502
Author(s):  
Louise Pearce ◽  
Chester M. Van Allen
Keyword(s):  
Physical State ◽  
Marked Decrease ◽  
Organ Weight ◽  
Ultraviolet Rays ◽  
Constant Darkness ◽  
Organic Reaction ◽  
Constant Illumination ◽  
Organ Weights ◽  
Especial Reference ◽  
Concrete Form

An analysis has been made of the organ weights of normal rabbits exposed to a constant illumination having none of the shorter ultraviolet rays and of other rabbits kept in darkness for periods of 2 to 12 weeks. The environment of constant illumination was associated with a well marked decrease in the relative weights of most organs, and in certain instances this occurred when the organ weights of the controls were becoming increasingly large. There was also an associated effect of stabilization of organ weight. The majority of the organs of rabbits caged in constant darkness also showed a tendency toward decreased and stabilized weights, but these effects were less pronounced than in the rabbits caged under conditions of constant illumination. A notable exception to this general result was the weight of the liver which was markedly increased. The results of this experiment support the conception that there is a relationship between light and the physical state of the animal organism which may be expressed in the concrete form implied by the trend or direction of organ weight.

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