scholarly journals LEBENDNACHWEIS VON EINZELELEMENTEN DES ENDOPLASMATISCHEN RETIKULUMS

1965 ◽  
Vol 27 (2) ◽  
pp. 433-440 ◽  
Author(s):  
Manfred Girbardt
Keyword(s):  
Electron Microscopy ◽  
Phase Contrast ◽  
Preparation Technique ◽  
Phase Contrast Microscopy ◽  
Membrane Systems ◽  
Thin Sections ◽  
Living State ◽  
Contrast Microscopy ◽  
Cell Components ◽  
A Cell

By means of a special selective preparation technique, it is possible to investigate in thin sections, by electron microscopy, areas of a cell that have been observed in the living state, by phase-contrast microscopy, up to the time of fixation. Structures recorded in the living state can thus be compared to structures seen in electron micrographs. In cells of the fungus Polystictus versicolor, aggregates of membrane systems as well as single cisternae with a diameter of approximately 200 to 300 A can be detected with phase optics. It can be shown, by calculation, that these structures, which are far below the limit of resolution of the light optical system, give enough contrast to be discernible by phase optics. Thus a basis is provided for observing the dynamics of membrane systems which perhaps may contribute to the analysis of the functional significance of these cell components.

scholarly journals STUDIES ON THE MODE OF ACTION OF EXCESS OF VITAMIN A

1963 ◽  
Vol 17 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Audrey M. Glauert ◽  
Mary R. Daniel ◽  
J. A. Lucy ◽  
J. T. Dingle
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Vitamin A ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Intact Cells ◽  
Thin Sections ◽  
Initial Effect ◽  
Contrast Microscopy ◽  
Site Of Action

Rabbit erythrocytes have been haemolysed by treatment with vitamin A alcohol and the sequence of changes in the fine structure of the cells during lysis has been investigated by phase contrast microscopy of intact cells and electron microscopy of thin sections. The initial effect of the vitamin, which occurs within 1 minute, is the production of cells of bizarre appearance which have a greatly increased surface area relative to untreated cells. Large indentations appear in the surfaces of the cells, and vacuoles are formed from the indentations by a process that resembles micropinocytosis. The cells then become spherical and loss of haemoglobin begins as breaks appear in the membranes of some cells; finally, ghosts are produced that are no longer spherical but still contain numerous vacuoles. These observations support the thesis that one site of action of vitamin A is at lipoprotein membranes.

Some Applications of Phase-Contrast Microscopy

1947 ◽  
Vol s3-88 (4) ◽  
pp. 491-499
Author(s):  
ROBERT BARER
Keyword(s):  
No Value ◽  
Phase Contrast ◽  
Limiting Factor ◽  
Phase Contrast Microscopy ◽  
Insect Larvae ◽  
Valuable Adjunct ◽  
Living State ◽  
Contrast Microscopy ◽  
Physical Case ◽  
Successful Employment

Some extensions of the simple theory of phase-contrast microscopy are considered. It is emphasized that transparency, rather than thickness, is the limiting factor for the successful employment of the method. Certain transparent insect larvae (Chaoborus, Chironomus) can be observed in the living state by phase-contrast illumination. The statement that the method is of no value for the examination of fixed and stained sections is based on consideration of an ideal physical case. In practice the method may be a valuable adjunct to routine examination of such material. Examples are given of the application of phase-contrast microscopy to normal and pathological stained sections.

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