Cell staining materials

Figure 9.1. Thin section of compact bone from Schleswig (cf. Table 9.1), after application of a cell stain (methylene blue). Besides the bone cells, exogenous cellular material in the hollow spaces (shown by arrows) indicates previous microbial invasions.

During primary wall formation the plastids contain starch and other materials which stain heavily with uranyl acetate and lead citrate. When the tracheid starts to form the Si layer, the plastid becomes surrounded by an endoplasmic reticulum. While the fate of these compounds is unknown, it can be envisaged that they are used for generation of energy and/or a source of cell wall materials. 

In this protocol additional steps are taken to eliminate starch from the isolated cell wall material to minimize erroneous estimations of glucose in later analytical procedures. In some plant material only small numbers of very tiny starch granules may be found after staining with iodine in potassium iodide (see Basic Protocol 1) and these may be deemed too few to warrant the drastic action necessary to remove the large amounts of starch found in cells of potatoes for example. If the starch granules are small in size (e.g., <10 pm), then they are likely pass though the 11 -pm nylon mesh and be lost from the cell wall material however, to remove large amounts of starch, additional treatments with dimethyl sulfoxide (DMSO) and/or a-amylase are required. 

In both the studies of Wight and Ross, and of Eisenstein and Kuettner, ruthenium red staining material was also found in the plasma membranes of endothelial cells and smooth muscle cells which was not removed with chondroitinase ABC and is therefore not chon-droitin sulfate or dermatan sulfate. 

Observations by several workers suggest that at least some of the ruthenium red staining material found in the plasma membranes of cells is heparan sulfate-containing proteoglycan. Cells in culture appear to synthesize three discreet pools of glycosaminoglycans ... 

Figure 4.2. Electron micrograph showing a cytoplasmic lipid droplet (cld) in a cell fixed with potassium ferrocyanide. Dark-staining material of variable thickness coats the surface of the droplet (arrows). The alveolar lumen (1) is denoted. Bar = 1 p.m. From Dylewski et al. (1984a) with permission.

Figure 8. Histochemical studies of alfalfa callus cells. A. Normal callus cells stained with aniline blue black for total protein before induction of regeneration. B. Callus cells stained with aniline blue black after induction of regeneration very darkly staining material is protein.

Pathologically, it consists of two populations of cells—epithelial and myoepithelial—arranged in a tubular, cribriform, and/or solid pattern (Fig. 9.20). Stromal deposits are usually either myxoid or hyaline material that is deposited with the lumens of cribriform spaces. The epithelial cells stain with a variety of cytokeratins... 

Fig. 1. Set up for sample staining and washing. Materials for cell staining, washing, and mounting coverslips are shown.

The presence of a nucleolus in most nuclei is so obvious that it is not surprising that its description appeared in the literature long ago as early as 1781 Fontana described nucleoli. The word nucleolus means little nucleus and, to be sure, on stained material nucleoli appear in the nucleoplasm as basophilic round or ovoid masses. With the aid of the light microscope and refined staining techniques, Cajal demonstrated that the nucleolus of the intestinal cell of the larvae of Diptera has a filamentous structure. Thirty years later, it was concluded from observations of a variety of tissues stained by silver impregnation or examined with the phase contrast microscope that nucleoli have a dual composition that includes a filamentous structure, or nucleolonema, and a homogenous inconsistent part, or the pars amorpha. ... 

Liver biopsy specimens from the two adult patients of Hoffman and Fredrickson (1965) showed mild intralobular accumulation of foam cells. Histochemically, the foam cells as well as a granular material within parenchymal cells stained well with oil-red and were weakly PAS-positive. The Schultz reaction for cholesterol revealed small foci of blue-green coloration in the parenchymal cells and brillant blue-green staining of the foam cells. 

Although osmium tetroxide stains the majority of cell components, a further staining procedure is needed in order to give the structure a sharper contrast, permitting better definition and resolution of the pictures. After several experimoits, uranium and lead salts were found to be the best staining materials however, their staining is rather aspecific and the chemical intoaction with the substrate is thus far not very clear. 

---