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 Visualization of nucleolar substructure in cultured human fibroblasts by magnesium-activated adenosine triphosphatase reaction.

1981 ◽  
Vol 29 (10) ◽  
pp. 1115-1120 ◽  
Author(s):  
N Fox ◽  
C Fernandez ◽  
G P Studzinski
Keyword(s):  
Adenosine Triphosphatase ◽  
Divalent Cations ◽  
Human Fibroblasts ◽  
Lead Nitrate ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Atpase Reaction ◽  
Cultured Human Fibroblasts ◽  
A Minor

Discrete sites of adenosine triphosphatase (ATPase) activity were demonstrated within the nucleoli of unfixed cultured human fibroblasts (IMR90, VA13, and AG2804 cells) by an adaptation, for electron microscopic cyto-chemistry, of Wachstein and Meisel's lead nitrate method. The majority of nucleoli contained more than one ATPase-positive region, but the total ATPase-positive material appeared to occupy only a minor portion of the nucleolar volume. These regions were roughly spherical with an irregular contour, and at times appeared to be components of perinucleolar chromatin or to be located adjacent to nucleolar interstices. The distribution of these regions within the nucleolus and their segregation by actinomycin D suggested that the ATPase-positive regions correspond to the fibrillar centers, which represent nucleolar organizer regions. The cytochemically demonstrable nucleolar ATPase was strictly dependent on the presence of divalent cations. Optimal reactions was seen at 5 mM Mg2+, but near optimal activity was obtained with lower concentrations of Mg2+ in the presence of Ca2+. Calcium alone and Mn2+ alone produced suboptimal reaction. Studies with different nucleoside phosphates as reaction substrates showed that the enzyme is specific for adenosine derivatives, ATP and dATP being equally good substrates. Guanosine triphosphate, cytidine triphosphate, uridine triphosphate, and d-thymidine triphosphate were ineffective as substrates, as were nucleoside mono- and diphosphates and other phosphate esters tested. It is suggested that the cytochemical ATPase reaction visualized the regions of the nucleolus in which ribosomal DNA of intranucleolar chromatin is undergoing conformational alterations.

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.

The Growth of Herpesvirus mulatto in Human Fibroblast

1974 ◽  
Vol 32 ◽  
pp. 244-245
Author(s):  
Glennelle Washington ◽  
Philip P. McGrath ◽  
Peter R. Graze ◽  
Ivor Royston
Keyword(s):  
Rhesus Monkey ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Peripheral Blood ◽  
Human Fibroblast ◽  
Rhesus Monkeys ◽  
Human Fibroblasts ◽  
Electron Microscopic ◽  
Specific Antisera ◽  
Peripheral Blood Leucocytes

Herpes-like viruses were isolated from rhesus monkey peripheral blood leucocytes when co-cultivated with WI-38 cells. The virus was originally designated rhesus leucocyte-associated herpesvirus (LAHV) and subsequently called Herpesvirus mulatta (HVM). The original isolations were from juvenile rhesus monkeys shown to be free of antibody to rhesus cytomegalic virus. The virus could only be propagated in human or simian fibroblasts. Use of specific antisera developed from HVM showed no relationship between this virus and other herpesviruses. An electron microscopic study was undertaken to determine the morphology of Herpesvirus mulatta (HVM) in infected human fibroblasts.

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.

Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism

1989 ◽  
Vol 47 ◽  
pp. 848-849
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
L. Stefaneanu ◽  
N. Losinski
Keyword(s):  
Nucleolar Organizer ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Ectopic Acth Syndrome ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Ectopic Acth ◽  
Crooke’S Hyalinization

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.

scholarly journals PROBLEMS ASSOCIATED WITH THE DEMONSTRATION BY LEAD METHODS OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN RESIDENT PERITONEAL MACROPHAGES AND EXUDATE MONOCYTES OF THE GUINEA PIG

1973 ◽  
Vol 21 (5) ◽  
pp. 488-498 ◽  
Author(s):  
R. E. POELMANN ◽  
W. T. DAEMS ◽  
E. J. VAN LOHUIZEN
Keyword(s):  
Plasma Membrane ◽  
Guinea Pig ◽  
Microscopic Study ◽  
Heterogeneous Nucleation ◽  
Adenosine Triphosphatase ◽  
Peritoneal Macrophages ◽  
Electron Microscopic ◽  
Adenosine Triphosphatase Activity ◽  
Eosinophilic Granulocytes ◽  
Membrane Bound

This cytochemical and electron microscopic study on peritoneal macrophages of the guinea pig has raised doubts concerning the validity of lead methods for the demonstration of plasma membrane-bound adenosine triphosphatase activity. The problems encountered are inherent in the use of lead ions as a capture reagent. The nonenzymatically formed precipitates reflect sites of heterogeneous nucleation specific for certain kinds of cells, e.g., resident peritoneal macrophages, eosinophilic granulocytes and, to a lesser degree, exudate monocytes. This type of precipitation is also catalyzed on the surface of nonbiologic matrices such as latex particles. Enzymatic processes may well occur, but they cannot be distinguished from nonenzymatic processes.

Sign in / Sign up

Export Citation Format

Share Document