| Popis: |
This study of the effect of caffeine upon the physiological processes underlying fertilization in the Arbacia egg by means of the physical changes in the finer structure of the cell, as revealed by electron microscopy, indicates the following. Negative results were obtained with reference to mitochondria and to the beaded, sheet-partition-like, double membranes scattered through the cytoplasm. These structures have been called sheets, fibers, endoplasmic reticulum, etc. These synonomous terms of different authors have been shown by Bernhard et al. (2) to be basophilic substances. No evidence was obtained that caffeine affects them. Positive results were observed showing caffeine effects as follows: 1. 1. The most drastic alteration of the ultramicroscopic structure of the mature, unfertilized Arbacia egg as shown by the electron micrographs of caffeine-treated eggs, is the disappearance of the papillated surface border. 2. 2. The degree of modification of the finer structural details is directly proportional to the concentration of the caffeine employed. 3. 3. The groundwork matrix of the egg becomes more compact and more minutely vacuolated. 4. 4. Pigment granules possess a double membrane which becomes more permeable to the release of echinochrome molecules; and the granule itself becomes swollen. 5. 5. The cortical granule matrix, especially the “Hub” area of the wheel-like “Hub” and “Spokes” configuration of the normal cell, becomes disorganized into one of three variations of its original form. 6. 6. An explanation is suggested for the change in the papilla-like border. |
