UBC Theses and Dissertations
The role of cytoplasmic protrusions in the intercellular adhesion of rat leukemia cells (line irc 741) Yit, Dominic Kwok-Wo
I. The function, structure and response to environmental factors of a cytoplasmic protrusion found in rat leukemia cells IRC 741 were investigated. A greater rigidity and adhesiveness of the protrusions, as compared to the main cell body, was demonstrated by time-lapse cinematography, and this functional difference was correlated with localized ultrastructural differences in the cytoplasm and on the cell surface, and with higher negative surface-charge density, as shown by cell electrophoresis. The formation or maintenance of the cytoplasmic protrusions depended on adequate nutritional conditions, and was interfered with by diminished intercellular contact, by environmental temperatures below 37°C, by alkaline pH and by calcium-ion depletion. The protrusion appears to represent a type of adhesive organelle not previously described in either cancer cells or normal cells. II. In the course of the above work, a method was developed whereby the differential staining of viable and nonviable unfixed cells, as observed by the dye-exclusion method, can be reproduced in glutaraldehyde-fixed preparations by staining with alcian blue. The results suggest that the differential staining is due, at least in part, to structural differences that are retained following aldehyde-fixation.
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