Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.5 (5'-nucleotidase)
3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

After stimulation of the mouse peritoneal cavity with newborn calf serum (NBCS), four types of monocyte and macrophage were distinguished on the basis of peroxidase (PO) patterns. Cytochemically, these cells showed strong heterogeneity in 5'-nucleotidase (5'N) activity. Monocytes and monocyte-derived macrophages with PO activity in granules lacked 5'N activity. Resident macrophages (with PO activity in RER and nuclear envelope) generally had significant 5'N activity on the plasma membrane, the pattern showing close correlation with the biochemical findings. The group of PO-negative macrophages comprised both 5'N-negative and 5'N-positive cells. These findings suggest two possibilities, i.e., that monocytes (5'N-)transform via PO-negative cells (5'N -/+) into resident macrophages (5'N +), or that the monocytes and monocyte-derived macrophages and the resident macrophages represent separate lineages. The fourth type of macrophage, the exudate-resident cell (with PO activity both in granules and in the RER and nuclear envelope), occurred only in low numbers and very late after NBCS stimulation, and is therefore considered not to be a transitional cell between monocytes and resident macrophages.
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PMID:Heterogeneity in 5'-nucleotidase activity of mouse peritoneal macrophages. An EM-cytochemical and biochemical study. 631 16

In the present report the characteristics of nonepithelial phagocytic cells of the murine thymic reticulum are described. Primary cultures were established from thymic fragments. Nonadherent cells with hairy membranes proliferated on the surface of established primary monolayers. These cells were recovered and replated in secondary cultures were they appeared as large adherent cells with dendritic shape. At the electron microscopic level, phagocytic cells of the thymic reticulum in culture (P-TR-C) appear as clear vacuolated cells with an indented nucleus and few lysosomes; this morphological aspect makes them different from the common macrophage, despite their phagocytic capacity. P-TR-C are positive for nonspecific esterase, acid phosphatase which is found in the few lysosomes present, 5'-nucleotidase and alpha-D-mannosidase, but negative for peroxidase. A high proportion of alpha-mannosidase-positive cells is inconsistent with the common macrophage, but in common with other cells with dendritic shape such as Langerhans cells. They are Thy-1-, Ig- and nearly half of them are IA+. P-TR-C can be defined as the stimulator cells for syngeneic stimulation; they are able to induce the proliferation of lymphocytes enriched in mature syngeneic medullary thymocytes, but not in immature cortical ones. Characteristics of P-TR-C make them very similar to the interdigitating cells described in the peripheral lymphoid organs and in the thymus in situ.
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PMID:Thymic reticulum in mice. II. Culture and characterization of nonepithelial phagocytic cells of the thymic reticulum: their role in the syngeneic stimulation of thymic medullary lymphocytes. 660 Oct 9

A membrane fraction denoted N2 upper was isolated from homogenates of rat liver by sucrose gradient centrifugation. This fraction, which was enriched 65-fold over the homogenate in 5'-nucleotidase activity, was used as an immunogen in goats. The antisera obtained contained antibodies to three predominant polypeptides in the N2 upper membrane fraction, as shown by crossed immunoelectrophoresis. These polypeptides had molecular weights of 105,000, 110,000, and 160,000 after recovery from the crossed immunoelectrophoretic gels and are denoted PM105, PM110, and PM160. Each was a distinct polypeptide, as shown by the distinct peptide patterns resulting from limited proteolysis in the presence of detergents. The three polypeptides were synthesized by primary cultures of hepatocytes and were externally oriented at the surface of these cells, as shown by their accessibility in situ to iodination catalyzed by lactoperoxidase. They were not detectable in the serum by crossed immunoelectrophoresis. The three antigens were present at very low (PM110) or nondetectable (PM105, PM160) concentrations in intracellular membrane fractions derived from the Golgi and smooth and rough endoplasmic reticulum of liver. The antigens also were reduced in concentration in a plasma membrane fraction most likely derived from the sinusoidal surface of the hepatocyte. The three membrane antigens bind to concanavalin A; hence, they are probably glycoprotein constituents of a discrete domain of the hepatocyte plasma membrane. Immune complexes were isolated after crossed immunoelectrophoresis and injected into rabbits. Each of the antisera obtained was reactive to one of the membrane polypeptides. Sections of fixed rat livers were reacted with each of the antibodies and then the primary antibody was localized by indirect immunocytochemical methods using horseradish peroxidase or colloidal gold as labels. Each of the three antigens was localized by this method to the bile canalicular domain of the hepatocyte plasma membrane.
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PMID:Establishment of plasma membrane domains in hepatocytes. I. Characterization and localization to the bile canaliculus of three antigens externally oriented in the plasma membrane. 664 79

Rat liver organelles involved in receptor-mediated endocytosis were labeled with a conjugate of galactosylated BSA to horseradish peroxidase [( 3H]galBSA-HRP), injected 10 min before sacrifice. These organelles were recovered at low density (1.11-1.13 g/ml) in sucrose gradients (Quintart, J., P. J. Courtoy, J. N. Limet, and P. Baudhuin, 1983, Eur. J. Biochem., 131:105-112). Upon incubation of such low density fractions in 3,3'-diaminobenzidine (DAB) and H2O2 and equilibration in a second sucrose gradient, galBSA-HRP-containing particles selectively shifted towards heavier densities (Courtoy, P. J., J. Quintart, and P. Baudhuin, 1984, J. Cell Biol., 98:870-876, companion paper), resulting in up to 250-to 300-fold purification with respect to the homogenate. The most purified preparations, wherein DAB-stained structures represented approximately 85% of the total volume of particles, contained only trace activities of enzymes usually regarded as markers for other subcellular entities. These minor activities could reflect either contamination or true enzyme association to the ligand-containing structures. Considering the latter hypothesis, at most 1.0% of alkaline phosphodiesterase I and 2.6% of 5'-nucleotidase (markers for plasma membrane), 3.6% of N-acetyl-beta-glucosaminidase (lysosomes), and 6.0% of galactosyltransferase (Golgi complex) from the homogenate would be associated with the whole population of ligand-containing organelles. After DAB cytochemistry on liver fixed 10 min after galBSA-HRP injection, ligand-containing structures accounted for 0.78-0.89% of the fractional volume of the hepatocytes and displayed a membrane area of 2,100 cm2/cm3, compared with 6,700 cm2/cm3 for the pericellular membrane. Altogether, our data support the hypothesis that these ligand-containing organelles are structurally distinct from plasma membrane, lysosomes, and Golgi complex.
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PMID:Receptor-mediated endocytosis in rat liver: purification and enzymic characterization of low density organelles involved in uptake of galactose-exposing proteins. 669 90

Alkaline phosphatase(AP),5'-nucleotidase(5'N) and nucleoside diphosphatase (NDPase) activities were studied by cytochemical methods applied to light and electron microscopy in the microvasculature of spinal cord leptomeningeal strips of normal and protamine sulfate (PS) treated rats. The increased permeability to intravenously injected horseradish peroxidase was observed in some segments of microvessels of PS treated rats. Enhanced formation of plasmalemmal pits and deep invaginations, formation of numerous pinocytic vesicles and the appearance of channel-like structures in the cytoplasm of endothelial cells were the most striking ultrastructural evidence of increased permeability of the affected microvessels. All of these structures also showed activity of AP, and to lesser extent, of NDPase; 5'N activity was mainly associated with the delimiting membranes of pinocytic vesicles. Our data present evidence that a shift of enzymatic activity from luminal to abluminal surface of affected endothelial cells results from membrane flow accompanying increased transport activity via formation of pinocytic vesicles and channel-like structures.
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PMID:Ultracytochemical studies of the blood-meningeal barrier (BMB) in rat spinal cord. 731 99

Many xenobiotics cause hepatobiliary toxicity and cholestasis in the rat. Initial assessment of hepatobiliary damage in rats can be accomplished by measuring serum concentrations of bile acids and bilirubin, serum activities of liver-associated enzymes such as 5'-nucleotidase, alkaline phosphatase, gamma-glutamyltranspeptidase, and plasma clearances of dyes [e.g., bromosulfophthalein (BSP)] excreted primarily through the bile. More detailed evaluation of hepatobiliary disturbances involves cannulation of the bile duct of anesthetized rats and subsequent measurement of rates of bile flow, bile acid excretion, and bile composition. Canalicular bile flow can be estimated from clearances of nonmetabolized sugars (i.e., erythritol) which enter bile via paracellular transport. Tight junction permeability also can be assessed by either biliary excretion of such a marker as horseradish peroxidase or sucrose following portal vein infusion or via retrograde biliary infusion. Subsequent morphologic evaluation of the liver provides information on damage to cells which may contribute to hepatobiliary dysfunction (i.e., bile duct obstruction). Isolated perfused livers offer the ability to measure all of the above mentioned parameters as well as to make a more accurate determination of the effects of xenobiotics on bile acid-dependent and -independent bile flow. A good example of the advantage of combining techniques as well as following complete time courses of changes in hepatobiliary function is provided by using studies of alpha-naphthylisothiocyanate-induced hepatotoxicity.
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PMID:Assessment of hepatobiliary function in vivo and ex vivo in the rat. 818 40

This study was done to determine glucagon's effect on protein biliary excretion in anesthetized, bile duct-cannulated guinea pigs. Glucagon (1.4 nmol.min-1.kg-1) induced choleresis and increased protein biliary concentration from 0.12 +/- 0.04 to 0.20 +/- 0.6 mg/ml and protein output from 22.8 +/- 3.8 to 54.5 +/- 16.1 micrograms.kg-1.min-1. Protein biliary excretion increased during the first 10 min of glucagon infusion and progressively declined thereafter. Biochemical analysis of biliary protein revealed that the increase could be accounted for primarily by an increase in the lysosomal enzymes acid phosphatase and beta-glucuronidase. Biliary excretion of the canalicular membrane enzymes 5'-nucleotidase and alkaline phosphatase only modestly increased, whereas that of [14C]sucrose, a marker of paracellular fluid transport, was unaffected. On the other hand, glucagon enhanced biliary entry of horseradish peroxidase in a fashion similar to that observed with total endogenous protein. These effects were mediated by the adenosine 3',5'-cyclic monophosphate (cAMP) system, since infusion of dibutyryl-cAMP at 0.5 mumol.kg-1.min-1 increased bile flow and biliary protein excretion in a time-dependent manner, as observed with glucagon. Glucagon's failure to sustain enhanced protein biliary output was not due to declining hepatic concentrations of cAMP or to depletion of hepatocellular lysosomal enzymes. These studies provide evidence that glucagon stimulates biliary excretion of protein in guinea pigs that can be accounted for by biliary discharge of enzyme originating from the canalicular membrane and, primarily, from the lysosomal compartment. Although the precise mechanism(s) underlying these effects remains to be elucidated, it is suggested that the increase in canalicular membrane enzyme excretion is due to glucagon's effect on exocytosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glucagon induces biliary protein excretion in guinea pigs. 838 43

The role of AMP and adenosine was investigated in the radiosensitization of normal brain tissues by chlorpromazine. Their metabolism was evaluated by estimating the levels of 5'-nucleotidase and adenosine deaminase activity in the brains of rats treated with chlorpromazine alone or chlorpromazine and irradiation. The extent of lipid peroxidation, measured in terms of the lipid peroxidase enzyme formed, increased with chlorpromazine treatment and irradiation. Chlorpromazine treatment was found to decrease AMP and adenosine metabolism, as shown by a marked reduction in the level of 5'-nucleotidase and ADA activity which was accompanied by a marked curtailment in the DNA, RNA and protein contents of the brain. Chlorpromazine was also found to increase the radiation-induced activity of acid phosphatase, indicating its action on the lysosomal activity of the brain cells. In the present study a low dose of chlorpromazine, i.e. 17 mg/kg body weight, was found to be more effective than a high dose of 34 mg/kg. The results of this study suggest that chlorpromazine probably sensitizes normal brain tissues to radiation by inhibiting AMP and adenosine metabolism via a hydroxy-radical induced decrease in DNA, RNA and protein metabolism with a concomitant increase in lysosomal activity.
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PMID:Effect of chlorpromazine as a sensitizer of rat brain on radiation-induced AMP and adenosine metabolism. 862 92

Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.
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PMID:Nitric oxide plays a role as second messenger in the ultraviolet-B irradiated green alga Chlorella pyrenoidosa. 2033 5


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