TY - JOUR
T1 - The structure of cytoplasm in directly frozen cultured cells. I. Filamentous meshworks and the cytoplasmic ground substance
AU - Bridgman, P. C.
AU - Reese, T. S.
PY - 1984
Y1 - 1984
N2 - Cultured fibroblasts or epithelial cells derived from Xenopus laevis embryos were directly frozen, freeze-substituted by an improved method, and then either critical-point-dried and viewed as whole mounts, or embedded and thin sectioned. In thin regions of these cells, where ice crystal artifacts are absent, the cytoplasm consisted of a dense, highly interconnected meshwork of filaments, embedded in a finely granular ground substance. The meshwork in directly frozen, intact cells was compared with that in cells that were lysed (physically, with detergents, or with filipin), or fixed with glutaraldehyde before freezing. Although filaments tended to be less numerous in lysed cells, their overall organization was the same as that in intact cells. However, fixation with glutaraldehyde before freezing distorted the meshwork to variable degrees depending on the osmolarity of the fixation buffer, and also obscured the granular ground substance which is obvious in directly frozen cells. With optimal preparative methods, the cytoplasm of these directly frozen cells is shown to consist of a cytoskeleton composed of discrete interwoven filaments interconnected by numerous finer filaments and a readily extractable granular matrix which presumably represents aggregations of cytoplasmic proteins.
AB - Cultured fibroblasts or epithelial cells derived from Xenopus laevis embryos were directly frozen, freeze-substituted by an improved method, and then either critical-point-dried and viewed as whole mounts, or embedded and thin sectioned. In thin regions of these cells, where ice crystal artifacts are absent, the cytoplasm consisted of a dense, highly interconnected meshwork of filaments, embedded in a finely granular ground substance. The meshwork in directly frozen, intact cells was compared with that in cells that were lysed (physically, with detergents, or with filipin), or fixed with glutaraldehyde before freezing. Although filaments tended to be less numerous in lysed cells, their overall organization was the same as that in intact cells. However, fixation with glutaraldehyde before freezing distorted the meshwork to variable degrees depending on the osmolarity of the fixation buffer, and also obscured the granular ground substance which is obvious in directly frozen cells. With optimal preparative methods, the cytoplasm of these directly frozen cells is shown to consist of a cytoskeleton composed of discrete interwoven filaments interconnected by numerous finer filaments and a readily extractable granular matrix which presumably represents aggregations of cytoplasmic proteins.
UR - http://www.scopus.com/inward/record.url?scp=0021734135&partnerID=8YFLogxK
U2 - 10.1083/jcb.99.5.1655
DO - 10.1083/jcb.99.5.1655
M3 - Article
C2 - 6436253
AN - SCOPUS:0021734135
SN - 0021-9525
VL - 99
SP - 1655
EP - 1668
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 5
ER -