The action of buffered potassium permanganate as a fixative for electron microscopy has been investigated. Electron contrast has been shown to be produced by the deposition of granular material in the tissue. The particles are about 50 A in diameter. Actual fixation of the tissue is performed by the dehydrating alcohol. Histochemical studies have shown that RNA and histones are removed, whereas...

The effect of potassium supply of Vicia faba on the fixation of molecular nitrogen by root nodules was studied by using (15)N-labeled molecular nitrogen. Plants well supplied with potassium showed higher contents of (15)N in the soluble amino fraction and in the protein fraction of various plant organs as compared with plants of a lower potassium status. This effect was evident particularly in ...

Tissue from 73 chick embryos incubated for periods between 1 and 13 days has been studied. Before fixation each specimen was staged according to the normal table of Hamburger & Hamilton (1951). The tissue was fixed either in osmium tetroxide, or in potassium permanganate (Luft, 1956). In either case the pH was buffered to 7-4 with sodium veronal (Palade, 1952) and fixation was at 0° C. In the e...

Tissue from 73 chick embryos incubated for periods between 1 and 13 days has been studied. Before fixation each specimen was staged according to the normal table of Hamburger & Hamilton (1951). The tissue was fixed either in osmium tetroxide, or in potassium permanganate (Luft, 1956). In either case the pH was buffered to 7-4 with sodium veronal (Palade, 1952) and fixation was at 0° C. In the e...

No significant change was found in the electrolytes and lipids of the brain analyzed after glutaraldehyde fixation by perfusion of laboratory animals; such fixation also satisfactorily preserves neural tissues for electron microscopy. The brains of normal and tumor-bearing C3H mice, Wistar rats, and New Zealand rabbits were studied. Little difference was found in the dry weight and the content ...