Histochemical Demonstration of the Sites of Activity of Dehydrogenase Systems With the Electron Microscope

Abstract

During an attempt to test current, and develop new, histochemical methods applicable to electron microscopy, early success was obtained with a method for demonstrating the activity of dehydrogenase systems. This method depends on the fact that potassium tellurite (K2TeOa) is reduced (hydrogenated) by living tissues to a product of high electron-scattering power. More specifically, this reagent will accept electrons indirectly from respiratory enzyme systems (dehydrogenases and associated enzymes) as metabolites are oxidized by dehydrogenation. The dehydrogenases or transhydrogenases (1) are reversibly oxidized and reduced, whereas the reduced tellurite is stable and insoluble.Klett (2) was the first to notice the reduction of tellurite to a black, insoluble compound by living bacteria and proposed the reaction as a viability criterion. Subsequent studies used this reagent or selenite on bacteria (3), plant cells (4), seeds (5, 6), and yeasts (7), and Lakon (6) attributed the reaction to the activity of dehydrogenases. Recently, Wachstein (8) revived the use of tellurite as a histochemical reagent for demonstrating the presence of endogenous dehydrogenase systems in fresh animal tissues.The tellurite reaction has certain features which render it potentially adaptable to electron microscopy. For instance, the final product, reduced tellurite, formed during this reaction, is extremely insoluble and hence, can be expected to precipitate in the immediate vicinity of the reaction sites. This metallic precipitate is opaque to electrons, thus satisfying a basic requirement for any product of a histochemical reaction to be used in electron microscopy. Consequently, the tellurite could be adopted if the preparative procedures could be rendered satisfactory for electron microscopy. The requirements to be met in enzyme histochemistry are numerous and varied. As shown in detail in a recent

Histochemistry and Cytochemistry of Experimentally Denervated Guinea Pig Muscle. I.

“…(Sedar and liosa [ 19501 rat m yocardium ;Barrnett and Palade [ 1957] heart muscle, kidney and other tissues; Oda [1958]; Walker and Seligman [1961] rat duodenum ; George and Talesara [1961] pigeon breast m uscle; Walker and Seligman [1963] liver and pancreas of rat; Ilitzeman [1963] Lcydig cells of testis.) Biochemical studies by Knouilton and Hines 119341 revealed a 55% decrease of SDH seven days after denervation in the rat gastrocnem ius muscle, but Levine, Hechter and Soskin [1941] failed to find any decrease by use of a different biochemical technique.…”

The Endoplasmic Reticulum as the Site of Potassium Tellurite Reduction in Yeasts

“…Barnett & Palade (1957) showed that in mammalian heart tissue with succinate as substrate tellurite was reduced mainly in the mitochondria, and this observation was interpreted as providing a basis for a histochemical method for demonstrating the presence of a mitochondria1 succinic dehydrogenase.…”

Tellurite reductase activity of nitrate reductase is responsible for the basal resistance of Escherichia coli to tellurite

“…Resistance to tellurite is conferred by highly specific genetic determinants (Walter & Taylor, 1992). Historically, tellurite has been used as an indicator for the localization of reducing activity in bacteria (Barrnett & Palade, 1957;Van Iterson & Leene, 1964). However, the enzymes responsible for this tellurite to tellurium reduction were unknown.…”