Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Na+ absorption across Aplysia gut was mediated by a Na+/K+-ATPase located in the enterocyte basolateral membrane. 2. In the absence of Na+ in the bathing medium, net Cl- absorption across Aplysia gut wall was identical to the SCC. 3. Intracellular Cl- was at a lower electrochemical potential in Aplysia enterocytes than in either the mucosal or serosal medium. 4. Cl--stimulated ATPase activity was localized in the basolateral membrane of Aplysia enterocytes. 5. ATP-dependent Cl- transport was localized in the basolateral membrane of Aplysia enterocytes. 6. In Aplysia gut primary active transport systems for both Na+ and Cl- are postulated based on the evidence presented.
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PMID:Sodium and chloride transport across the molluscan gut. 290 69

Mucosal loperamide caused a dose dependent reduction in the absorption of actively transported hexoses and amino acids, together with the associated rise in short circuit current. Na+ and fluid movement were also inhibited. Serosal application of the drug was without effect on these processes. The passive movement of fructose across the gut was not affected by loperamide which is therefore unlikely to act by reducing tissue permeability. In low Na+ conditions the inhibitory actions of loperamide on glycine absorption were reduced. Loperamide reduced basal Na+ transport although it did not affect the stimulation of Na+ absorption caused by mannose. Loperamide had no effect on the total ATPase activity nor on the Na+, K+-ATPase activity of mucosal homogenates. The effects of loperamide were not mimicked by morphine nor were they antagonised by naloxone and hence do not seem to involve an opiate receptor. It is concluded that loperamide exerts its inhibitory effects by an interaction with the Na+ sites of the nutrient carriers.
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PMID:Inhibitory actions of loperamide on absorptive processes in rat small intestine. 372 Dec 92

The contractile axostyle is a ribbon-shaped organelle present in certain species of flagellates found in the hindgut of wood eating insects. This organelle propagates an undulatory wave whose motion, like flagella and cilia, is related to microtubules. Unlike the axoneme of cilia and flagella, however, the axostyle is composed of singlet microtubules linked together in parallel rows. Axostyles were isolated from Cryptocercus gut protozoa with Triton X-100. Normal motility of the isolated axostyle could be restored with adenosine triphosphate (ATP); the specific conditions necessary for this reactivation were essentially identical with those reported for the reactivation of isolated flagella or whole sperm. ATPase activity of the isolated axostyle was comparable to the values reported for ciliary or flagellar axonemes. The axostyle was reasonably specific for ATP. Most of the proteins of the isolated axostyle comigrated with proteins of the ciliary axoneme on sodium dodecyl sulfate (SDS) polyacrylamide gels (i e. equivalent molecular weights). These included the following: the higher molecular weight component of dynein, tubulin, linkage protein (nexin), and various secondary proteins. Evidence for dynein in the axostyle is presented and a model proposed to explain how repeated propagated waves can be generated.
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PMID:Isolation and reactivation of the axostyle. Evidence for a dynein-like ATPase in the axostyle. 434 62

The exchange of labelled calcium between the external medium and the whole body was investigated in the larva of Aedes aegypti (L.) using a closed, two-compartmental model. The transport system for the uptake of Ca2+ was found to be saturable and obeyed Michaelis-Menten kinetics. The efficiency of the inward transport of calcium from dilute solutions was markedly reduced by starvation or by ruthenium-red, a selective inhibitor of Ca2+ activated ATPase, indicating that this transport system is energy dependent. Unlike transport systems for the major monovalent ions, the Ca2+ transport system is not located in the anal papillae, since removal of these organs resulted in enhanced Ca2+ fluxes. While over 95% of the calcium in the larva appeared to be distributed in the extracellular haemolymph, only 16% of the total calcium was readily exchangeable with the external medium; thus the majority of the calcium is apparently bound to haemolymph constituents. The results suggest that calcium pumps consisting of Ca2+ activated ATPases play an important role in the absorption of Ca2+ from dilute solutions in the gut and its reabsorption from the urine in the rectum.
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PMID:The exchange of calcium in larvae of the mosquito Aedes aegypti. 619 97

The long term (90 days) effects of medroxyprogesterone acetate (MPA) administration on the digestive and absorptive functions of the small gut have been investigated in female albino rats. The uptake of glucose and amino acids was found to be significantly increased while Ca++ uptake decreased following MPA treatment (35 mg/kg body weight). The observed increase in glucose uptake might be due to carrier mediated transport in enterocytes and not to a change in cell number. The Michaelis constant for glucose uptake was not altered by MPA. Activities of brush border membrane disaccharidases, leucine aminopeptidase and basolateral membrane enzyme Na+, K+-ATPase were significantly increased in response to MPA treatment. It was observed that these biochemical alterations caused by MPA in intestinal digestive and absorptive functions were reversible by 5 weeks after termination of the drug treatment. The action of the drug appears to closely resemble that of known effects of glucocorticoids on intestinal mucosa.
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PMID:Alterations and reversibility of digestive and absorptive functions of rat intestine following medroxyprogesterone acetate administration. 623 20

The lipid composition and fluidity of basolateral membranes prepared from the mucosa of the proximal, middle and distal thirds of the rat small intestine were determined. Fluidity, as assessed by the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene and a series of anthroyloxy fatty acid derivatives, is decreased in the distal third as compared to the proximal segments. This pattern is similar to that described previously for microvillus membranes. The decrease in fluidity of the distal as compared to the proximal membranes results from an increase in cholesterol content, cholesterol/phospholipid molar ratio and degree of saturation of the fatty acid residues. In the middle and distal thirds of the gut, the degree of saturation of the fatty acid residues is higher in microvillus as compared to basolateral membranes, accounting in part for the characteristically lower fluidity of the luminal membranes. The specific activity of the basolateral membrane (Na+ + K+)-dependent adenosine triphosphatase is significantly lower in the distal as compared to the proximal and middle thirds of the intestinal mucosa. Studies of the binding of [3H]ouabain indicate that this pattern results from fewer enzyme sites in the distal membranes.
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PMID:Lipid composition and fluidity of rat enterocyte basolateral membranes. Regional differences. 632 92

Using monoclonal antibodies on fresh frozen endoscopically obtained oesophageal biopsies the distribution of Langerhans cells, B lymphocytes, and various subpopulations of T lymphocytes was studied in the normal human oesophageal mucosa and in oesophagitis. Identification of the lymphocytes was carried out by an immunoperoxidase technique using OKT3 (antihuman T cell antibody), OKT4 (antihuman helper T cell antibody), OKT8 (antihuman cytotoxic T cell) and OKT10 (antihuman null cell antibody). Identification of the Langerhans cells was carried out using an ATPase stain and OKIa (Ia like antigen) and OKT6 (antihuman thymocyte). In the normal oesophageal epithelium cytotoxic T lymphocytes are found as well as Ia positive Langerhans cells. Helper T lymphocytes and B lymphocytes are present mainly in the lamina propria. In oesophagitis an increase in Langerhans cells and cytotoxic T lymphocytes within the epithelium is found. From these findings it can be concluded that the oesophagus contains a reticuloepithelial system as well as a lymphocytic population which are a part of the gut-associated lymphoid tissue.
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PMID:Lymphocytes and Langerhans cells in the human oesophageal epithelium. 641 48

Calcium ATPase, an enzyme involved in intestinal calcium transport, was measured in homogenates of duodenal mucosal scrapings of normal and uremic rats. The effects of calcium deprivation and treatment with 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] were investigated as well. Uremia decreased the enzyme activity and impaired the rise after calcium deprivation as observed in intact rats. The 1,25-(OH)2D3 treatment increased the enzyme activity in uremic animals and resulted in an identical response to calcium deprivation as observed in intact rats; parathyroidectomy abolished this effect. A striking correlation between everted duodenal gut sac calcium transport and calcium ATPase activity could be demonstrated for all groups of rats studied. It is concluded that the calcium ATPase activity is linked to the production of 1,25-(OH)2D3 as well as to an additional factor, probably parathyroid hormone. The close relationship between enzyme activity and in vitro calcium transport, even during constant physiological supplementation with 1,25-(OH)2D3, suggests an autonomous role of the calcium ATPase activity for mediation of calcium transport in the duodenum in addition to the well-known mechanisms related to vitamin D and its metabolites.
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PMID:Calcium ATPase and intestinal calcium transport in uremic rats. 644 89

A new giant Gram-negative non-cultivatable symbiotic endospore-forming bacterium was found in the gut of the European hamster. This "Metabacterium" sp., provisionally named "Metabacterium criceti", sp. n., has a length of approximately 20 microns and thickness of 4 microns. It forms 1 to 2 cylindrical endospores, approximately 9 microns long and 1.4 microns thick. TEM-micrographs show a cell wall structure characteristic of Gram-negative bacteria. Vegetative cells are filled with granules 0.3 micron in diameter which resemble starch granules. The reproduction occurs with binary fission and by formation of two endospores. Of thirteen biochemical components sought, four, i.e. glycogen, triacylglycerols, peroxidase and alkaline phosphatase, were not found. Starch, acid mucosubstances, DNA, RNA, lipids, proteins, adenosine triphosphatase and acid phosphatase were found in different patterns, depending on the developmental stage of the bacterium. In the vegetative cell stage all these components, with the exception of starch, were found. In the endospore-bearing cell stage, only the starch-like cell component granules could be detected. In free endospores only DNA, RNA and acid phosphatase were found. Some of the components, i.e. DNA, lipids, starch-like granules, were linked to certain cell substructures, the distribution of others, viz. polysaccharides, RNA, adenosine triphosphatase and proteins was diffuse. The lipids, found only in vegetative cells, were associated with the cell wall.
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PMID:Characterization of two Metabacterium sp. from the gut of rodents. 1. Morphology and histochemical examination of a new Metabacterium sp. from the gut of the European hamster (Cricetus cricetus) 769 4

1. The absorption mechanism of polaprezinc (zinc-carnosine chelate compound) was studied in rat by an everted gut sac method. The rates of transport and accumulation of 14C-L-carnosine were proportional to the mucosal concentration of L-carnosine, whereas the rates of transport and accumulation of 65ZnCl2 had become saturated. The Michaelis-Menten constant (Km) = 4.41 mM and maximal rate (Vmax) = 71.83 nmol/min/g for zinc transport and, similarly, Km = 6.21 mM and Vmax = 92.51 mumol/30 min/g for accumulation. 2. The addition of ouabain, 2,4-dinitrophenol (2,4-DNP) and low temperatures reduced the rate of zinc uptake, indicating that zinc transport was considered to be a carrier-mediated process based on Na+,K(+)-ATPase-dependent mechanisms. 3. The concentration of zinc in the gut of the non-fasted rat was greater than that of the fasted rat, suggesting different rates of transport and accumulation. It is suggested that zinc intestinal uptake in rat is regulated by zinc content in the gut. 4. A pharmacokinetic model for transport and accumulation of zinc saturation from the lumen side to the gut was designed, and the calculated values obtained by simultaneous multiline fitting of transport and accumulation of zinc data were in good agreement with the observed values.
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PMID:Absorption mechanism of polaprezinc (zinc L-carnosine complex) by an everted sac method. 770 50


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