Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changing patterns of enzyme activity and solute transport in response to washing were investigated in red beet (Beta vulgaris L.) storage tissue. Washing had a pronounced effect on the plasma membrane (PM) H+-ATPase with an increase in both hydrolytic and proton-pumping activities. Immunoblotting indicated that this may be due, in part, to a higher amount of this enzyme in the PM of washed tissue. Activities of the tonoplast (V)H+-ATPase and pyrophosphatase fluctuated during a 4-d washing period, but overall showed no marked change in activity. In tissue discs sucrose (Suc), glucose (Glc), and fructose uptakes increased significantly in response to washing. Cycloheximide, cordycepin, and tunicamycin inhibited both Glc- and Suc-inducible uptake. Monensin also strongly inhibited inducible Glc uptake, but the effect on Suc was less marked. N-Ethylmaleimide inhibited both Suc and Glc uptake, with its effects being more pronounced in fresh tissue. Other protein-modifying reagents showed no significant difference in their level of inhibition between fresh and washed tissue. Transport studies, carried out using energized PM vesicles from fresh and washed tissue, indicated that there was no rise in Suc and Glc uptake rates in response to washing. Results with a range of inhibitors indicated that there was no marked change in transporter sensitivity in vesicles isolated from fresh and washed tissue. The results indicate that the well-described enhancement of solute transport in washed storage tissue may be due to an increased PM H+-ATPase activity rather than to changes in PM carrier activity or to changes in metabolism such as invertase activity.
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PMID:Effects of Prolonged Washing on Primary and Secondary Transport Processes at the Plasma Membrane in Red Beet Storage Tissue. 1222 6

The rat undergoes profound maturational changes in the intestinal structure and function during the third week of its life. To investigate the role of peripheral glucocorticoid metabolism in this process, we studied the postnatal maturation of intestinal structure and function. The peripheral metabolism of glucocorticoids depends on enzyme 11beta-hydroxysteroid dehydrogenase (11betaHSD), which is responsible for the interconversion of corticosterone to 11-dehydrocorticosterone and thus for the modulation of glucocorticoid access to corticosteroid receptors. The pups were treated with carbenoxolone (CBX), an inhibitor of 11betaHSD, for 10 d during the suckling (days 8-18) or weaning period (days 14-24 or days 20-30), and we determined the parameters of intestinal growth and activities of sucrase, alkaline phosphatase, and Na,K-ATPase. The CBX treatment increased plasma concentrations of corticosterone as a result of a significant reduction of peripheral degradation of corticosterone catalyzed by 11betaHSD. This also stimulated intestinal growth without changing somatic growth. The mucosal cell mass was significantly higher in CBX-treated suckling rats, whereas the effect of this treatment was less obvious in weanling animals. CBX increased the crypt depth and villus height in 18- and 24-d-old pups but not in 30-d-old animals. The small intestinal activities of sucrase, alkaline phosphatase, and Na,K-ATPase were not influenced by CBX. In contrast, colonic Na,K-ATPase was stimulated by CBX. We conclude that the administration of CBX results in acceleration of intestinal growth and structural maturation without any influence on the developmental pattern of brush-border hydrolases. The results indicate an important role of peripheral glucocorticoid metabolism in the regulation of intestinal growth during early postnatal life.
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PMID:Carbenoxolone accelerates maturation of rat intestine. 1262 Nov 20

Glycosphingolipids are widely viewed as integral components of the Golgi-based machinery by which membrane proteins are targeted to compartments of the endosomal/lysosomal system and to the surface domains of polarized cells. The yeast Saccharomyces cerevisiae creates glycosphingolipids by transferring mannose to the head group of inositol phosphorylceramide (IPC), yielding mannosyl-IPC (MIPC). Addition of an extra phosphoinositol group onto MIPC generates mannosyldi-IPC (M(IP)2C), the final and most abundant sphingolipid in yeast. Mannosylation of IPC is partially dependent on CSG1, a gene encoding a putative sphingolipidmannosyltransferase. Here we show that open reading frame YBR161w, renamed CSH1, is functionally homologous to CSG1 and that deletion of both genes abolishes MIPC and M(IP)2C synthesis without affecting protein mannosylation. Csg1p and Csh1p are closely related polytopic membrane proteins that co-localize with IPC synthase in the medial-Golgi. Loss of Csg1p and Csh1p has no effect on clathrin- or AP-3 adaptor-mediated protein transport from the Golgi to the vacuole. Moreover, segregation of the periplasmic enzyme invertase, the plasma membrane ATPase Pma1p and the glycosylphosphatidylinositol-anchored protein Gas1p into distinct classes of secretory vesicles occurs independently of Csg1p and Csh1p. Our results indicate that protein sorting in the late Golgi of yeast does not require production of mannosylated sphingolipids.
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PMID:Protein sorting in the late Golgi of Saccharomyces cerevisiae does not require mannosylated sphingolipids. 1458 28

1. Intestinal brush border membrane vesicles (BBMV) were prepared from 3-week-old broiler chickens. 2. Electron microscopy of the BBMV fraction showed single membrane vesicles of different sizes with no electron dense material inside. No other organelles were observed. The sucrase and maltase activities were enriched by factors of 16 and 18, respectively, in the BBMV fraction in comparison with the homogenate. On the other hand, the Na+/K+-ATPase sensitivity to ouabain was increased by a factor of 0.8. 3. The BBMV showed a maximum L-[14C]-arginine uptake (944.9 +/- 22.9 pmoles/mg protein) at 45 s and thereafter it declined slowly. In the presence of 0.5 mM L-canavanine, the L-[14C]-arginine uptake by BBMV was reduced by 43.6% at 45 s. 4. It is concluded that L-canavanine inhibits L-arginine Na+-dependent transport across the enterocyte apical membrane in a highly purified intestinal BBMV from broiler chickens.
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PMID:L-canavanine inhibits L-arginine uptake by broiler chicken intestinal brush border membrane vesicles. 1458 53

Epithelial cells were successfully isolated along the intestine of the gilthead seabream using a dissociation method based on intracellular-like solutions. Biochemical and physiological tests revealed highly viable cells from all intestinal segments. Image analysis was used to identify cell types in the epithelial preparations which were highly enriched in enterocytes (>95%) over mucous cells. Several digestive hydrolases were determined in the isolated cells. Maltase (M), sucrase (S), leucine aminopeptidase (LA), 5'nucleotidase (5'N), but not gamma-glutamyl transferase (gamma-GT) or alkaline phosphatase (AP) activities were found to be enriched in the epithelial preparations versus the corresponding intestinal homogenates. Comparison of digestive hydrolases revealed the existence of a clear heterogeneity in their expression pattern in the enterocytes, along the intestine. Na(+)-K(+)-ATPase, Na(+)-ATPase and Cl(-)-ATPase activities were also determined in the membrane fraction of isolated cells. Analyses of enzymatic profiles revealed a clear asymmetry in the distribution of all Mg(2+)-dependent ATPases; that is, maximal Na(+)-K(+)- and Na(+)-ATPase activities were observed in the enterocytes from pyloric caeca, while Cl(-)-ATPase activity was about twice as high in the enterocytes from anterior and posterior intestines compared with pyloric caeca. This is the first report demonstrating the existence of heterogeneous metabolic and enzymatic profiles in different enterocyte populations from euryhaline teleosts.
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PMID:Isolation and characterization of enterocytes along the intestinal tract of the gilthead seabream (Sparus aurata L.). 1547 77

Brush border membrane vesicles (BBMV) enriched in sucrase, maltase and alkaline phosphatase, and impoverished in Na(+)-K(+)-ATPase, were isolated from proximal and distal intestine of the gilthead sea bream (Sparus aurata) by a MgCl(2) precipitation method. Vesicles were suitable for the study of the characteristics of D-glucose apical transport. Only one D-glucose carrier was found in vesicles from each intestinal segment. In both cases, the D-glucose transport system was sodium-dependent, phlorizin-sensitive, significantly inhibited by D-glucose, D-galactose, alpha-methyl-D-glucose, 3-O-methyl-D-glucose and 2-deoxy-D-glucose, and showed stereospecificity. Apparent affinity constants of D-glucose transport (K(t)) were 0.24 +/- 0.03 mM in proximal and 0.18 +/- 0.03 mM in distal intestine. Maximal rate of influx (Jmax) was 47.3 +/- 2.2 pmols. mg(-1) protein for proximal and 27.3 +/- 3.6 pmols. mg(-1) protein for distal intestine. Specific phlorizin binding and relative abundance of an anti-SGLT1 reactive protein were significantly higher in proximal than in distal BBMV. These results suggest the presence of the same D-glucose transporter along the intestine, with a higher density in the proximal portion. This transporter is compatible with the sodium-dependent D-glucose carrier described for other fish and with the SGLT1 of higher vertebrates.
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PMID:Na-dependent D-glucose transport by intestinal brush border membrane vesicles from gilthead sea bream (Sparus aurata). 1563 May 46

Actin filaments are thought to play an important role in intracellular trafficking in various eukaryotic cells. However, their involvement in intracellular trafficking in plant cells has not been clearly demonstrated. Here, we investigated the roles actin filaments play in intracellular trafficking in plant cells using latrunculin B (Lat B), an inhibitor of actin filament assembly, or actin mutants that disrupt actin filaments when overexpressed. Lat B and actin2 mutant overexpression inhibited the trafficking of two vacuolar reporter proteins, sporamin:green fluorescent protein (GFP) and Arabidopsis thaliana aleurain-like protein:GFP, to the central vacuole; instead, a punctate staining pattern was observed. Colocalization experiments with various marker proteins indicated that these punctate stains corresponded to the Golgi complex. The A. thaliana vacuolar sorting receptor VSR-At, which mainly localizes to the prevacuolar compartment, also accumulated at the Golgi complex in the presence of Lat B. However, Lat B had no effect on the endoplasmic reticulum (ER) to Golgi trafficking of sialyltransferase or retrograde Golgi to ER trafficking. Lat B also failed to influence the Golgi to plasma membrane trafficking of H+-ATPase:GFP or the secretion of invertase:GFP. Based on these observations, we propose that actin filaments play a critical role in the trafficking of proteins from the Golgi complex to the central vacuole.
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PMID:Actin filaments play a critical role in vacuolar trafficking at the Golgi complex in plant cells. 1572 71

The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birth. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infection, or antibiotic therapy was commenced on day 5 and the animals killed on day 14 (n = 5). Compared with the non-infected controls, infected animals had reduced mucosal lactase and sucrase, but not maltase activity, while after antibiotic therapy, previously infected piglets had a lower lactase and a higher maltase and sucrase activity. Lactase activity was significantly reduced in the duodenum and jejunum, and mean values were lower in the ileum, but the difference did not reach significance; maltase activity was greater at all ages from the distal jejunum to the mid-ileum; sucrase activity was reduced in all segments up to day 5 but after antibiotic therapy was increased in the jejunum and appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. There was a reduced villus height:crypt depth ratio, crypt hyperplasia and increased crypt cell proliferation. Morphological maturation, indicated by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 14 days of age when only the ileum remained immature. In infected piglets, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected piglets appears to be due to physical damage to the mucosa resulting in faster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impair the ability to utilise dietary carbohydrate and may have long-term effects on growth and immunological responses of the gut.
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PMID:Impact of Yersinia enterocolitica enteritis on disaccharidase activity and small intestinal morphology in colostrum-deprived newborn piglets. 1603 44

Cadmium (Cd) uptake effects on sucrose content, invertase activities, and plasma membrane functionality were investigated in Rangpur lime roots ( CITRUS LIMONIA L. Osbeck). Cadmium accumulation was significant in roots but not in shoots and leaves. Cadmium produced significant reduction in roots DW and increment in WC. Leaves and shoots did not show significant differences on both parameters. Sucrose content was higher in control roots than in Cd-exposed ones. Apoplastic sucrose content was much higher in Cd-exposed roots than in control ones. Cd-exposed roots showed a significant decrease in both cell wall-bound and cytoplasmic (neutral) invertase activities; while the vacuolar isoform did not show any change. Alterations in lipid composition and membrane fluidity of Cd-exposed roots were also observed. In Cd-exposed roots phospholipid and glycolipid contents decreased about 50 %, while sterols content was reduced about 22 %. Proton extrusion was inhibited by Cd. Lipid peroxidation and proton extrusion inhibition were also detected by histochemical analysis. This work's findings demonstrate that Cd affects sucrose partitioning and invertase activities in apoplastic and symplastic regions in Rangpur lime roots as well as the plasma membrane functionality and H (+)-ATPase activity.
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PMID:Cadmium induces changes in sucrose partitioning, invertase activities, and membrane functionality in roots of Rangpur lime (Citrus limonia L. Osbeck). 1688 81

The effect of dietary phytate and phytase on carbohydrase activity and hexose transport was investigated in broiler chickens. Diets containing phytate P (2.2 or 4.4 g/kg) with different phytase dose rates (0, 500, or 1,000 phytase units/kg) were fed to 504 female Cobb chicks for 3 wk. Diets containing high phytate concentrations depressed (P < 0.05) BW and G:F, whereas phytase supplementation improved (P < 0.05) the performance of birds. In the duodenum, phytate decreased (P < 0.05) the activities of disaccharidases, Na(+)K(+)-ATPase, and glucose concentrations by 5 to 11%, but phytase enhanced (P < 0.05) the concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose by 5 to 30%. In the jejunum, phytate decreased (P < 0.05) the concentrations of amylase, sucrase, Na(+)K(+)-ATPase, and glucose by 10 to 22%, and phytase alleviated the negative effect of phytate on the above variables. Ingestion of diets containing phytate also decreased (P < 0.05) serum amylase activity and glucose concentration, and phytase enhanced (P < 0.05) serum concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose. There were also interactions (P < 0.05) between phytate and phytase on the concentrations of serum amylase, duodenal amylase, sucrase, and jejunal glucose. Enzymatic analysis at a molecular level showed that neither phytate nor phytase influenced the mRNA expression of sucrase-isomaltase in the small intestine. Also, the investigation into the sodium glucose cotransporter gene may challenge the mechanism by which phytate interferes with glucose utilization, as partly indicated by bird performance, and transmembrane transport because diets containing increased phytate upregulated (P < 0.05) the mRNA expression of the sodium glucose cotransporter gene in duodenum and did not influence it in the jejunum. These results indicate that phytate can impair endogenous carbohydrase activity and digestive competence, and phytase can ameliorate these effects for chickens.
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PMID:Effect of diet containing phytate and phytase on the activity and messenger ribonucleic acid expression of carbohydrase and transporter in chickens. 1870 94


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