Use of tetrazolium compounds in oxidative enzyme histo- and cytochemistry

Leptin receptor defect with diabetes causes skeletal muscle atrophy in female obese Zucker rats where peculiar depots networked with mitochondrial damages

Tibialis anterior muscles of 45-week-old female obese Zucker rats with defective leptin receptor and non-insulin dependent diabetes mellitus (NIDDM) showed a significative atrophy compared to lean muscles, based on histochemical-stained section's measurements in the sequence: oxidative slow twitch (SO, type I) < oxidative fast twitch (FOG, type IIa) < fast glycolytic (FG, type IIb). Both oxidative fiber's outskirts resembled 'ragged' fibers and, in these zones, ultrastructure revealed small clusters of endoplasm-like reticulum filled with unidentified electron contrasted compounds, contiguous and continuous with adjacent mitochondria envelope. The linings appeared crenated stabbed by circular patterns resembling those found of ceramides. The same fibers contained scattered degraded mitochondria that tethered electron contrasted droplets favoring larger depots while mitoptosis were widespread in FG fibers. Based on other interdisciplinary investigations on the lipid depots of diabetes 2 muscles made us to propose these accumulated contrasted contents to be made of peculiar lipids, including acyl-ceramides, as those were only found while diabetes 2 progresses in aging obese rats. These could interfere in NIDDM with mitochondrial oxidative energetic demands and muscle functions.

Using (1)H magnetic resonance imaging and complementary analytical techniques to characterize developmental changes in the Zantedeschia Spreng. tuber

Nuclear magnetic resonance imaging (MRI) and complementary analytical techniques were used to examine tissue structure and developmental changes occurring during active growth in the root tuber of ZANTEDESCHIA: Spreng. cv. Chianti, a commercially significant cut flower. Plants were observed during the period of leaf senescence and tuberization at the end of the first growth cycle of micropropagated plantlets and, following cool storage to break endodormancy, during development occurring after the replanting of ecodormant tubers. MRI distinguished two distinct regions within the tuber, and the differences in the binding state of water in the two regions were reflected in differences in tissue morphology and function. An abundance of free water was observed in tissue comprised of large parenchyma cells, at the base of the tuber. This tissue appeared to be involved in maintaining the viability of the plant during the period of dormancy, a function indicated primarily by increased metabolic activity in this tissue during dormancy, and reduced metabolic activity during periods of active growth. In contrast, water was more tightly bound in tissue comprised of small parenchyma cells. This tissue appeared to operate as a region for dynamic carbohydrate storage. The initial increase in the free water content of this tissue during the growth phase was linked to the mobilization of starch during canopy development. The subsequent decrease in free water in the remainder of the growth period was linked to the reaccumulation of starch while the tuber functioned as a sink for photosynthate prior to canopy senescence.

The use of formalin fixation in the cytochemical demonstration of succinic and DPN- and TPN-dependent dehydrogenases in mitochondria

Brief formalin fixation in the cold prior to histochemical assay of rat liver and pancreas for various dehydrogenases has been used successfully to circumvent the structural damage and enzymatic loss to which mitochondria of frozen sections would otherwise be subject. To obtain an optimal result a single set of conditions has been devised, including fixation prior to freezing of minute (finely diced) organ blocks in graded concentrations (0.7 to 2.0 per cent) of formaldehyde in chilled (1–4°C) Hanks' balanced salt solution, freezing at not higher than -70°C, and use of nitro-BT or, preferably, tetranitro-BT. The present histochemical study of hepatic and acinar cells indicates that not only are succinic and D-β-hydroxybutyric dehydrogenases located exclusively in the mitochondria but so are lactic, malic, and the isocitric dehydrogenases.

The use of tetranitro-blue tetrazolium for the cytochemical localization of succinic dehydrogenase. Cytochemical and cytological studies of sarcoma 37 ascites tumor cells

Succinic dehydrogenase (SDH) was localized in the mitochondria of Sarcoma 37 ascites tumor cells by the use of tetranitro-BT (TNBT) and nitro-BT (NBT) in smear preparations. Results with each tetrazolium salt as electron acceptor were evaluated with respect to: (a) size and shape of the formazan precipitate relative to standard mitochondrial morphology; (b) crystallization phenomena of reduced dye; (c) lipid adsorption of formazan. The association of formazan- or iron hematoxylin-stained mitochondria with lipid droplets within the cells was investigated, as was also the influence of formalin fixation, with and without cold acetone pretreatment, on mitochondrial morphology and enzymatic staining. Data from these studies appear to indicate that TNBT is more suitable than NBT for use as a cytochemical reagent in oxidative and/or dehydrogenase enzyme histochemistry and cytochemistry.

LOCALIZATION OF THE SUCCINIC DEHYDROGENASE SYSTEM IN ESCHERICHIA COLI USING COMBINED TECHNIQUES OF CYTOCHEMISTRY AND ELECTRON MICROSCOPY

The activity of the succinic dehydrogenase system was studied in Escherichia coli utilizing combined techniques of cytochemistry and electron microscopy. Organisms were incubated in a medium containing tetranitro-blue tetrazolium (TNBT) which served as an electron acceptor. Enzymatic activity, as evidenced by the deposition of aggregates of TNBT-formazan, was found associated with the site of the plasma membrane of the bacterium.

Effects of superior mesenteric and coeliac ganglionectomy on the small intestinal mucosa in the Hanford mini pig. I. Histological and enzyme-histochemical study

The effects of total superior mesenteric and coeliac ganglionectomy on the thickness of the mucosa, the cell composition of the epithelium and the enzyme activity of the absorptive cells was studied in 10 Hanford mini pigs 3 weeks and 6 months after ganglionectomy. The mucosal thickness increased after ganglionectomy by 10-33% (P less than 0.02) mainly due to increase in the villus height. Differential cell counts showed a postganglionectomy decrease in percentage of goblet cells of 20-40%. Absorptive cell counts increased significantly (P less than 0.05). Enterochromaffin cells (stained with the Masson-Fontana method) and 5-hydroxytryptamine (5-HT)-immunoreactive cells did not change significantly in the small intestine. The activity of L-leucine-amino-peptidase, non-specific alkaline phosphatase, adenosintriphosphatase, non-specific acid phosphatase, non-specific esterase and succinate dehydrogenase, as assessed by absorption photometry, increased by 2-18% (P less than 0.01) after ganglionectomy. Total ganglionectomy thus results in a rise in villus height and in an increase in the number of absorptive cells which, by their enzymatic activity, appear to be fully mature.

The demonstration of the succinic dehydrogenase system in Bacillus subtilis using tetranitro--blue tetrazolium combined with techniques of electron microscopy

Activity of the succinic dehydrogenase system was studied in Bacillus subtilis utilizing combined techniques of cytochemistry and electron microscopy. Organisms were incubated in a medium containing tetranitro-blue tetrazolium (TNBT) which served as an electron acceptor. Enzymatic activity, as evidenced by deposition of TNBT-formazan, was found on membranous organelles associated with the cytoplasmic membrane and septal plasma membrane, the nuclear area, and the plasma membrane. Flagella, approximately 190 A in diameter, with thorn-like projections protruded through the cell wall. Tangential-oblique sections of the cell wall showed many pores approximately 220 A in diameter with a center-to-center spacing of approximately 450 A.