Organelles and the Cytoskeleton in Mammalian Cells
Dr. B.J. Soltys
This page is dedicated to Keith Porter, pioneer of electron microscopy and one of the most eminent
cell biologists of the century. Few may know that Porter was born a Canadian, born in the east coast province of Nova Scotia which is known principally for its lobster and fishing industry, picturesque coastline and quaint towns. There he attended Acadia
University and later went on to doctoral studies at Harvard. Here you will see contemporary imaging of mammalian cells that was influenced directly or indirectly by Keith Porter's own very early work.
1. Below is fluorescence imaging of endoplasmic reticulum and mitochondria at the peripheral edge of a human fibroblast cell, Staining was done using the cyanine dye DiOC6(3). Endoplasmic reticulum was first discovered by Porter in his electron microscopic studies on mammalian cells. In this micrograph both mitochondria, which are the more strongly fluorescent tubular structures, and endoplasmic reticulum, which forms a meshwork, are labeled by the dye.
2. Whole mount electron microscopy of cells: a method first used by Porter to obtain the first electron micrograph of a cell. Shown here are cells growing on (A) glass coverslips and (B) EM grids. Cells in A and B are being microinjected (see the tip of the needle in B?). Part C is a low magnification whole mount electron micrograph of a human fibroblast taken at 80 kV.
3. Electron microscopy of the cytoskeleton. (a) Correlative fluorescence and electron microscopy of microtubules (left) and F-actin (right). Cells grown on EM grids were microinjected with fluorescent tubulin or actin, photographed first using fluorescence microscopy and then whole mounts were immunogold labeling using antibody against the fluorescent dye. (b) Immunogold labeled microtubules in a human fibroblast whole mount preparation.
4. A drug-induced mitochondrial reticulum. The drug used was ethacrynic acid. Mitochondria in these whole mounts are observed as electron-dense tubular structures. Part A shows the edge of a control cell, while part B shows a drug-treated cell in which mitochondria have become elongated and apparently fused to each other.
5. First identification of endoplasmic reticulum in
Giardia lamblia, the most primitive eukaryote (see Giardia website).
6. Historical electron micrographs taken by Keith Porter. Below are Figures 2 and 10 from the classic 1945 paper by Porter, Claude and Fullam showing two of the first electron micrographs ever obtained of a tissue culture cell. The figure on the right is a higher magnification of the top right of the cell on the left. Reproduced from The Journal of Experimental Medicine (1945) Vol 81, pg. 233 by copyright permission of The Rockefeller University Press.
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