The structure of the major cell processes of BHK21/C13 fibroblasts was examined by phase contrast, differential interference and polarization optics and by the electron microscopy of thin sections and whole cell replicas. In living cells, the optical studies revealed a birefringent streak extending along the length of the processes. In fixed cells, in addition to endoplasmic reticulum and filamentous mitochondria, microtubules and smaller tubular filaments were seen within the cytoplasm and bundles of microfilaments just under the cell membrane. The latter structures could be correlated with oriented, fibrous material seen in the whole cell replicas. The microtubules and filaments were frequently associated with each other. Possible functions for these filamentous structures in producing and maintaining cell processes and in intra- and extracellular motility are proposed and the relationship of these structures to the birefringence seen in living cells is discussed.
ASJC Scopus subject areas
- Cell Biology