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:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influences of Zn and Cu on soil enzyme activities (acid phosphatase, alkaline phosphatase, arylsulfatase, cellulase, dehydrogenase, protease (z-FLase), urease, beta-D-glucosidase and beta-D-fructofuranosidase (invertase)) and microbial biomass carbon were investigated in agricultural soils amended with municipal sewage sludge or compost since 1978. The trace metals in the soils were fractionated using a sequential extraction method. Long-term application of the sewage sludge and composts caused accumulations of Cu and Zn in the soils, ranging from 140 to 144 and from 216 to 292 mg kg(-1), respectively. The percentage of Cu was highest in the NaOH- and HNO3-extractable fractions (44-51% and 38-46%, respectively), while the percentage of Zn was highest in the HNO3- and EDTA-extractable fractions (65-83% and 11-32%, respectively). Although the percentage of the bioavailable fractions (sum of KNO3 + H2O-, NaOH-, and EDTA-extractable amounts) of Cu (53-64%) was higher than that of Zn (15-37%), the percentage of the most labile fractions (KNO3 + H2O) of Zn (2.1-5.9%) was larger than that of Cu (1.1-2.4%). The size of the microbial biomass carbon increased with the application of sewage sludge or compost. For some enzymes, however, the ratio of the enzyme activity to microbial biomass was lower in the soils amended with sewage sludge or compost than that in the control soil. The soil enzyme activities were more adversely affected by Zn than by Cu. From a multiple regression analysis, it was found that dehydrogenase, urease, and beta-D-glucosidase activities were reduced by the KNO3 + H2O-extractable fraction of Zn in the soils. These microbial activities seem to be sensitive to Zn stress, indicating the possibility that they might be useful bioindicators for evaluation of the toxic effects of Zn on microorganisms in the soils.
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PMID:Copper and zinc fractions affecting microorganisms in long-term sludge-amended soils. 1148 Sep 22

Bird-pollinated flowers are known to secrete relatively dilute nectars (with concentrations averaging 20-25% w/w). Many southern African plants that are pollinated by passerine birds produce nectars with little or no sucrose. Moreover, these hexose nectars are extremely dilute (10-15%). This suggests a link between sugar composition and nectar concentration. Nectar originates from sucrose-rich phloem sap, and the proportion of monosaccharides depends on the presence and activity of invertase in the nectary. Hydrolysis of sucrose increases nectar osmolality and the resulting water influx can potentially convert a 30% sucrose nectar into a 20% hexose nectar, with a 1.56 times increase in volume. Hydrolysis may also increase the gradient for sucrose transport and thus the rate of sugar secretion. When sucrose content and refractometer data were compared, some significant correlations were seen, but the occurrence of sucrose-rich or hexose-rich nectars can also be explained on phylogenetic grounds (e.g. Erythrina and Protea). Hexose nectars may be abundant enough to drip from open flowers, but evaporation leads to much variability in nectar concentration and increases the choices available to pollinators.
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PMID:Pollination by passerine birds: why are the nectars so dilute? 1192 80

The relationships between cellulose accumulation, changes in specific activities of enzymes of sucrose catabolism, levels of UDP-glucose and rate of dark respiration were investigated in the subapical 1 cm-hypocotyl region of 10- to 14-day-old-sunflower seedlings (Helianthus annuus L). The plants were grown under a light/dark regime in vermiculite that was soaked either with distilled water or half-strength Hoagland nutrient solution. At this stage of seedling development, the hypocotyl had ceased to elongate but increased in width. Stem thickening and the rate of cellulose accumulation were promoted by nutrient solution. The levels of the soluble (vacuolar) and wall-associated acid invertases (EC 3.2.1.26) were not correlated with these processes. However, the activities of the soluble (cytoplasmic) and membrane-bound sucrose synthases (EC 2.4.1.13) were larger in hypocotyls that were grown in the presence of nutrient solution. The concentration of UDP-glucose was reduced, and the rate of dark respiration was enhanced in the hypocotyls that were grown in Hoagland solution. The results support the hypothesis that both forms of the enzyme sucrose synthase play a critical role in cellulose biosynthesis of hypocotyl cells that had ceased to elongate and continue to grow by wall thickening.
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PMID:Sucrose metabolism and cellulose biosynthesis in sunflower hypocotyls. 1206 Feb 59

Water deficit during meiosis in pollen mother cells of wheat (Triticum aestivum L.) induces male sterility, which can reduce grain set by 40 to 50%. In plants stressed during meiosis and then rewatered, division of pollen mother cells proceeds normally but subsequent pollen development is arrested 3 or 4 d later. An inhibition of starch accumulation within the pollen grain suggested that an alteration in carbohydrate metabolism or assimilate supply may be involved in pollen abortion. We measured levels of various carbohydrates and activities of key enzymes of Suc metabolism and starch synthesis at different stages of pollen development in anthers collected from well-watered and water-stressed plants. Compared to controls, soluble sugars increased in anthers stressed during meiosis, then decreased at later poststress stages. Sucrose and myoinositol accounted for part of the sugar accumulation. The activity of soluble acid invertase declined 4-fold during the stress period and never recovered thereafter. Sucrose synthase activity during starch accumulation in pollen was also lower in the anthers of plants stressed at meiosis. Stress had little negative effect on the activities of ADP-glucose pyrophosphorylase or soluble and granule-bound starch synthase during starch accumulation in pollen, although at the earlier stages, ADP-glucose pyrophosphorylase activity in stressed anthers was slightly lower compared to controls. The results suggest that carbohydrate starvation per se and inhibition of the enzymes of starch synthesis probably were not responsible for the stress-induced pollen abortion. Instead, an inability to metabolize incoming sucrose to hexoses may be involved in this developmental lesion.
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PMID:Induction of Male Sterility in Wheat by Meiotic-Stage Water Deficit Is Preceded by a Decline in Invertase Activity and Changes in Carbohydrate Metabolism in Anthers. 1222 80

Water deficit during pollination increases the frequency of kernel abortion in maize (Zea mays L.). Much of the kernel loss is attributable to lack of current photosynthate, but a large number of kernels fail to develop on water-deficient plants even when assimilate supply is increased. We examined the possibility that assimilate utilization by developing ovaries might be impaired at low water potential ([Psi]w). Plants were grown in the greenhouse in 20-L pots containing 22 kg of amended soil. Water was withheld on the first day silks emerged, and plants were hand-pollinated 4 d later when leaf [Psi]w decreased to approximately - 1.8 MPa and silk [Psi]w was approximately -1.0 MPa. Plants were rehydrated 2 d after pollination. The brief water deficit inhibited ovary growth (dry matter accumulation) and decreased kernel number per ear by 60%, compared to controls. Inhibition of ovary growth was associated with a decrease in the level of reducing sugars, depletion of starch, a 75-fold increase in sucrose concentration (dry weight basis), and inhibition of acid invertase (EC 3.2.1.26) activity. These results indicate that water deficits during pollination disrupt carbohydrate metabolism in maize ovaries. They suggest that acid invertase activity is important for establishing and maintaining reproductive sink strength during pollination and early kernel development.
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PMID:Low Water Potential Disrupts Carbohydrate Metabolism in Maize (Zea mays L.) Ovaries. 1222 65

Sucrose:sucrose 6-fructosyltransferase, an enzyme activity recently identified in fructan-accumulating barley (Hordeum vulgare) leaves, was further characterized. The purified enzyme catalyzed the transfer of a fructosyl group from sucrose to various acceptors. It displayed some [beta]-fructosidase (invertase) activity, indicating that water could act as fructosyl acceptor. Moreover, it transferred the fructosyl residue of unlabeled sucrose to [U-14C]Glc, producing [U-14C]sucrose and unlabeled glucose. Most significantly for fructan synthesis, the enzyme used as acceptors but not as donors a variety of oligofructans containing [beta](2->1)- and [beta](2->6)-linked fructosyl moieties. Thus, it acted as a general sucrose:fructan fructosyltransferase. The products formed by the enzyme from sucrose and various purified, structurally characterized oligofructans were analyzed by liquid chromatography and identified by comparison with structurally characterized standards. The results showed that the enzyme formed exclusively [beta](2->6) fructosyl-fructose linkages, either initiating or elongating a fructan chain of the phlein type. We propose, therefore, to rename the purified enzyme sucrose:fructan 6-fructosyltransferase.
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PMID:Sucrose:Fructan 6-Fructosyltransferase, a Key Enzyme for Diverting Carbon from Sucrose to Fructan in Barley Leaves. 1222 31

Invertase production by Aspergillus niger grown by solid-state fermentation was found to be higher than by conventional submerged fermentation. The haploid mutant strains Aw96-3 and Aw96-4 showed better productivity of various enzymes, as compared to wild-type parental strain A. niger C28B25. Here we use parasexual crosses of those mutants to increase further the productivity of invertase in solid-state fermentation. We isolated both a diploid (DAR2) and an autodiploid (AD96-4) strain, which were able to grow in minimal medium after mutation complementation of previously isolated haploid auxotrophic strains. Invertase production was measured in solid-state fermentation cultures, using polyurethane foam as an inert support for fungal growth. Water activity value (Aw) was adjusted to 0.96, since low Aw values are characteristic in some solid-state fermentation processes. Such diploid strains showed invertase productivity levels 5-18 times higher than levels achieved by the corresponding haploid strains. For instance, values for C28B25, Aw96-3, Aw96-4, DAR2, and AD96-4 were 441, 254, 62, 1324, and 2677 IU/(L x h), respectively. These results showed that genetic recombination, achieved through parasexual crosses in A. niger, results in improved strains with potential applications for solid-state fermentation processes.
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PMID:Invertase production on solid-state fermentation by Aspergillus niger strains improved by parasexual recombination. 1239 11

The development of immune-mediated diabetes in BB rats may involve a defect of the gastrointestinal tract (GI), as suggested by increased gut permeability. This study aimed at measuring invertase, maltase, lactase, and peroxidase activities in the duodenum of diabetesprone BioBreeding (BBdp) rats and control BioBreeding rats (BBc) given free access to NIH-07 diet up to the time of killing at 60 66 d of age. After washing the entire small intestine, the duodenal mucosa was scraped off in the first 5-cm segment from the pylorus and frozen in distilled water. Invertase, maltase, and lactase activities were measured by monitoring the conversion of [U-(14)C]sucrose, [U-(14)C]maltose, and [D-[1-(14)C]glucose] lactose to radioactive hexoses, which were phosphorylated in the presence of adenosine triphosphatase and yeast hexokinase and then separated from their precursor by ion-exchange chromatography. Peroxidase activity was measured by a spectrophotometric procedure. In the BBdp rats, the activity of invertase, maltase, and lactase averaged, respectively, 70.2 +/- 4.4, 81.2 +/- 4.3, and 75.7 +/- 4.1% (n = 16 and p < 0.001 in all cases) of the control values found in BBc rats of the same sex. Inversely, after exclusion of two female BBc rats with abnormally high plasma D-glucose concentration, the activity of peroxidase in the BBdp rats averaged 157.4 +/- 20.0% (n = 16; p < 0.02) of the mean control value recorded in BBc rats of the same sex (100.0 +/- 9.3%; n = 14). These findings are compatible with the view that a proinflammatory state of the GI associated with compromise function may precede the occurrence of pancreatic insulitis in BBdp rats and, possibly, human subjects with type 1 diabetes.
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PMID:Invertase, maltase, lactase, and peroxidase activities in duodenum of BB rats. 1262 29

A biohydrogen production system coupling the polysaccharide such as sucrose and maltose degradation with invertase and glucose dehydrognase (GDH) and hydrogen production with colloidal platinum as hydrogen-evolved catalyst using the visible light-induced photosensitization of water-soluble zinc porphyrin, zinc tetraphenylporphyrin tetrasulfonate (ZnTPPS) has been investigated. Continuous hydrogen gas production was observed when the sample solution containing polysaccharide, invertase, GDH, nicotinamide adenine dinucreotide (NAD(+)), ZnTPPS, methylviologen (an electron relay reagent), and colloidal platinum was irradiated by visible light. After 240-min irradiation, the amount of hydrogen production in the system using sucrose and maltose was estimated to be 3.1 and 0.35 micromol, respectively.
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PMID:Bio-mimetic hydrogen production from polysaccharide using the visible light sensitization of zinc porphyrin. 1267 71

Among the numerous molecular and physiological modifications induced by water deficit, one of the earliest events observed in maize mature leaves subjected to water deprivation was a strong enhancement of acid vacuolar invertase activity, which occurred before the classical reduction in gas exchange due to stomatal closure. The increase in invertase activity coincided with the rapid accumulation of glucose and fructose that reached 8-fold the control leaf value. In addition, acid vacuolar invertase activity appeared to be highly correlated with xylem sap ABA concentration. In order to investigate the nature of the relationship between ABA and invertase activity, and to disconnect ABA from a likely sucrose side-effect, excised leaves were supplied with ABA or sucrose. As a consequence of ABA supply, a peak in leaf ABA appeared 4 h later which was followed by an enhancement of vacuolar invertase activity. ABA supply also produced a second maximum in leaf ABA. The transcript level of the Ivr2 gene encoding one vacuolar invertase presented the same two peaks pattern as leaf ABA, with a 2 h lag. This response was specific since the other invertase genes were not responding. Thus, ABA appeared to be a powerful enhancer of the IVR2 vacuolar invertase activity and expression. In the present conditions, the addition of sucrose had no effect on the enzyme activity.
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PMID:The role of abscisic acid in the response of a specific vacuolar invertase to water stress in the adult maize leaf. 1292 69


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