Cytochemical localization of Ca2+-Mg2+ adenosine triphosphatase in rat incisor ameloblasts during enamel secretion and maturation.

1987 ◽  
Vol 35 (4) ◽  
pp. 471-482 ◽  
Author(s):  
A H Salama ◽  
A E Zaki ◽  
D R Eisenmann
Keyword(s):  
Adenosine Triphosphatase ◽  
Cell Membranes ◽  
Developmental Stages ◽  
Electron Microscopic ◽  
Enamel Formation ◽  
Rat Incisor ◽  
Cytochemical Localization ◽  
Intense Reaction ◽  
Enamel Mineralization ◽  
Electron Microscopic Cytochemistry

A modified Wachstein-Meisel medium containing lead or cerium as capturing ions was used to localize Ca2+-Mg2+ adenosine triphosphatase (ATPase; EC 3.6.1.3) in rat incisor ameloblasts during enamel formation. Sections representing different developmental stages were processed for electron microscopic cytochemistry. Distribution and intensity of the observed reaction product, which was almost exclusively associated with cell membranes, varied according to the stage of enamel formation. During the secretory stage, intense reaction product was evident along the entire plasma membrane of ameloblasts and papillary cells. The early transitional ameloblasts showed reaction product on their proximal and lateral cell membranes, but not distally. In late transitional (pre-absorptive) ameloblasts, distal cell membranes exhibited intense reaction product. During enamel maturation, smooth-ended ameloblasts showed reaction product proximally and laterally, but not distally. Ruffle-ended maturative ameloblasts exhibited intense reaction product along their lateral and distal membranes. The intensity of the latter was decreased but not eliminated by levamisole. In the transition from smooth-ended to ruffle-ended cells, the reaction product became evident distally, concomitant with the appearance of cell membrane invaginations. These data are consistent with a possible role for Ca2+-Mg2+ ATPase in controlling calcium availability at the enamel mineralization front.

scholarly journals Cytochemical localization of calcium and Ca2+,Mg2(+)-adenosine triphosphatase in colchicine-altered rat incisor ameloblasts.

1990 ◽  
Vol 38 (10) ◽  
pp. 1469-1478 ◽  
Author(s):  
D R Eisenmann ◽  
A H Salama ◽  
A M Zaki ◽  
S H Ashrafi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Adenosine Triphosphatase ◽  
Morphological Changes ◽  
Rat Incisor ◽  
Cytochemical Localization ◽  
Early Maturation ◽  
Transmission Electron ◽  
Maturation Stages ◽  
Secretory Transport

Colchicine is known to affect secretory, transport, and degradative functions of ameloblasts. The effects of colchicine on membrane-associated calcium and Ca2+,Mg2(+)-ATPase in secretory and maturation ameloblasts were investigated cytochemically. The pyroantimonate (PPA) method was used for localizing calcium and a modified Wachstein-Meisel medium was used to localize Ca2+,Mg2(+)-ATPase. Sections representing secretory and early maturation stages were examined by transmission electron microscopy. Morphological changes induced by colchicine included dislocated organelles and other well-established reactions to such anti-microtubule drugs. Calcium pyroantimonate (Ca-PA) deposits in most ameloblast types were markedly reduced, with the greater reduction occurring in those cells more severely altered morphologically. However, the cell membranes of both control and experimental smooth-ended maturation ameloblasts were essentially devoid of Ca-PA. The normal distribution and intensity of Ca2+,Mg2(+)-ATPase was not affected by colchicine. Because the observed reduction of membrane-associated calcium is apparently not mediated by Ca2+,Mg2(+)-ATPase in this case, other aspects of the calcium regulating system of ameloblasts are apparently targeted by colchicine.

Electron microscopic cytochemical localization of a basolateral calcium adenosine triphosphatase in vitamin D replete chick enterocytes

1987 ◽  
Vol 219 (4) ◽  
pp. 384-393 ◽  
Author(s):  
Walter L. Davis ◽  
Ruth Gwendolyn Jones ◽  
Gene R. Farmer ◽  
James L. Matthews ◽  
James H. Martin ◽  
...  
Keyword(s):  
Vitamin D ◽  
Adenosine Triphosphatase ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Calcium Adenosine Triphosphatase

scholarly journals DNA dependence and inhibition by novobiocin and coumermycin of the nucleolar adenosine triphosphatase (ATPase) of human fibroblasts.

1982 ◽  
Vol 30 (4) ◽  
pp. 364-370 ◽  
Author(s):  
N Fox ◽  
G P Studzinski
Keyword(s):  
Adenosine Triphosphatase ◽  
Elevated Temperatures ◽  
Human Fibroblasts ◽  
Nucleolar Organizer ◽  
Electron Microscopic ◽  
Dna Topoisomerase ◽  
B Subunit ◽  
Electron Microscopic Cytochemistry ◽  
Nucleolar Chromatin ◽  
A Subunit

We have recently demonstrated by electron microscopic cytochemical methods that unfixed human fibroblasts exhibit intense MG2+ dependent adenosine triphosphatase (nATPase) activity in circumscribed areas of the cell nucleoli. The nATPase was specific for ATP and dATP and was inhibited by other ribonucleoside triphosphates. Its intranucleolar localization relative to nucleolar chromatin, and segregation into nucleolar zones after actinomycin treatment of the cells, suggested that the reaction took place in fibrillar centers. This ATPase has now been further characterized by electron microscopic cytochemistry. It was determined that short fixation permitted retention of most of the ATPase activity, and that the enzyme was active at high ionic strength (up to 400 mM KCl), but that the enzyme activity was very sensitive to elevated temperatures. DNA dependence of the enzyme was shown by inhibition of the reaction by DNase pretreatment in parallel with the removal of DNA from the cell, while pretreatment with RNase had no significant effect. The nATPase activity was also selectively inhibited by treatment of the cells with antagonists of the B subunit of DNA gyrase, novobiocin, and coumermycin, but not by nalidixic or oxolinic acids, which interfere with the A subunit of gyrase. Inhibitors of RNA synthesis, actinomycin D and aminonucleoside of puromycin, potentiate rather than inhibit nATPase reaction. The results suggest that nATPase functions to alter the degree of supercoiling or catenation of nucleolar organizer DNA, and is in reality a DNA topoisomerase that hydrolyzes ATP during its action.

scholarly journals Cytochemical localization of malate synthase in amphibian fat body adipocytes: possible glyoxylate cycle in a vertebrate.

1986 ◽  
Vol 34 (5) ◽  
pp. 689-692 ◽  
Author(s):  
W L Davis ◽  
R G Jones ◽  
D B Goodman
Keyword(s):  
Fat Body ◽  
Glyoxylate Cycle ◽  
Malate Synthase ◽  
Biochemical Pathway ◽  
Marker Enzymes ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Electron Microscopic Cytochemistry ◽  
Fat Bodies ◽  
The Glyoxylate Cycle

The adipocytes of amphibian abdominal fat bodies contain typical microperoxisomes, as indicated by their fine structure. Electron microscopic cytochemistry showed that these organelles contain the enzymes catalase, typical for peroxisomes, and malate synthase. The latter is an enzymatic component characteristic of the glyoxylate cycle, a biochemical pathway known to exist in plant glyoxysomes (peroxisomes). This metabolic pathway makes possible the net conversion of lipid to carbohydrate. Toad adipocytes may represent yet another example of vertebrate peroxisomes which contain one of the marker enzymes (malate synthase) characteristic of the glyoxylate shunt.

EM of human atherosclerosis: Aortic fatty streaks with transitional lesion features

1992 ◽  
Vol 50 (1) ◽  
pp. 622-623
Author(s):  
K. Florian Klemp ◽  
J.R. Guyton
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Processing Technique ◽  
Foam Cell Formation ◽  
Tissue Preparation ◽  
Electron Microscopic ◽  
Extracellular Lipid ◽  
Electron Microscopic Cytochemistry ◽  
Human Atherosclerosis ◽  
Clinically Significant

The earliest distinctive lesions in human atherosclerosis are fatty streaks (FS), characterized initially by lipid-laden foam cell formation. Fibrous plaques (FP), the clinically significant lesions, differ from FS in several respects. In addition to foam cells, the FP also exhibit fibromuscular proliferation and a necrotic core region rich in extracellular lipid. The possible transition of FS into mature FP has long been debated, however. A subset of FS described by Katz etal., was intermediate in lipid composition between ordinary FS and FP. We investigated this hypothesis by electron microscopic cytochemistry by employing a tissue processing technique previously described by our laboratory. Osmium-tannic acid-paraphenylenediamine (OTAP) tissue preparation enabled ultrastructural analysis of lipid deposits to discern features characteristic of mature fibrous plaques.

Ultrastructural Cytochemical Study of Human Gastric Cancer: Observation of AKP ase,ACP ase,G6P ase,TPP ase and CO ase

1990 ◽  
Vol 48 (3) ◽  
pp. 254-255
Author(s):  
Dong Yuming ◽  
Yang Guanglin ◽  
Du Wei Dong ◽  
Xu Ai Liam
Keyword(s):  
Gastric Cancer ◽  
Gastric Epithelium ◽  
Human Gastric Cancer ◽  
Electron Microscopic ◽  
Cytochemical Study ◽  
Electron Microscopic Cytochemistry ◽  
Cytochemical Reaction ◽  
Set Up ◽  
Cancer Tissues ◽  
Cytochemical Technique

The activities and distributions of AKPase ,ACPase,G6Pase,TPPase and COase in human normal gastric mucosa and gastric cancer tissues were studied histochemically at light microscopic level. These enzymes are the marker enzymes of cell membrane lysosome endoplasmic reticulum, Golgi apparatus and mitochondrion objectively. On the basis of the research we set up a special ultrastructural cytochemical technique and first researched into gastric cancer domesticly. Ultrastructural cytochemistry is also called electron microscopic cytochemistry. This new technique possesses both the sensitivity of cytochemical reaction andi the high resolution of electron microscope. It is characterized by direct observation,exact localization and the combination morphology with function.The distributions of AKPase,ACPase,G6Pase,TPPase and COase in 14 cases of gastric cancer and 1 case of gastric Denign lesion were studied ultrastructurally. The results showed: 1. normal gastric epithelium had no AKPase reaction. The reaction of ACPase,G6Pase,TPPase and Coase were found in the corresponding organella, which were consistent with their function.

BRIEF REPORT: Freeze-Cleaving of Red Cell Membranes in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
1967 ◽  
Vol 30 (6) ◽  
pp. 785-791 ◽  
Author(s):  
RONALD S. WEINSTEIN ◽  
ROGER A. WILLIAMS
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Membranes ◽  
Red Cells ◽  
Red Cell ◽  
Electron Microscopic ◽  
Structural Differences ◽  
Microscopic Studies ◽  
Red Cell Membranes

Abstract Electron microscopic studies on dried isolated red cell ghosts have been reported to show lesions associated with cell membranes in paroxysmal nocturnal hemoglobinuria (PNH). In this study, carbon-platinum replicas of membranes of freeze-cleaved, partially hydrated PNH red cells and isolated PNH cell ghosts failed to confirm the existence of these abnormalities. This suggests that the previously described lesions are the products of drying artifacts, although they may reflect hidden structural differences between PNH and normal red cell membranes.

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