title: A correlation between mode of growth and regional ultrastructure of the plasma membrane of Schizosaccharomyces pombe as revealed by freeze-fracturing before and after filipin treatment.
abstract: The ultrastructure of the plasma membrane of Schizosaccharomyces pombe was studied by freeze-fracture using invaginations of the plasma membrane as natural markers and filipin-induced deformations as artificial markers. In accord with the mode of growth of this organism, ultrastructural aspects of the plasma membrane were related to the following ring zones: the growing pole, adjacent regions, proximal regions, the new cell pole, and the middle in dividing cells. The growing pole and adjacent regions had no or only a few invaginations. Filipin induced numerous deformations in these regions. By contrast, the proximal regions of the plasma membrane had several invaginations and resisted filipin-induced deformation. Concomitantly with commitment to cytokinesis, both the invaginations and the resistance to filipin-induced deformation disappeared in the middle. The results presented here strongly suggest the existence of two states of the plasma membrane of S. pombe, a fact which correlates well with the mode of growth of this organism.
mesh_terms: D001203:Ascomycota / Q000648:ultrastructure*; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D004072:Digitonin / Q000494:pharmacology; D005372:Filipin / Q000494:pharmacology*; D005614:Freeze Fracturing; D011090:Polyenes / Q000494:pharmacology*; D012568:Schizosaccharomyces / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure*
chemical_list: D011090:Polyenes; D005372:Filipin; D004072:Digitonin