Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

New pyridine monoterpene alkaloids (PMTAs) have been synthesized from the iridoid glycosides 8-epi-loganin, cornin, and antirrinoside by treatment with beta-glucosidase and aqueous NH4-OAc. The PMTA from antirrinoside contained an 8-alpha-OAc group from the opened 7,8-epoxide moiety. Treatment of genipin, the aglycone of geniposide, with HCl(g) and NH3(g) yielded the PMTA racemigerine, a known plant isolate, in which the C=C-CH2OH side chain was converted to C=C-CH3. Reaction of geniposide with beta-glucosidase and aqueous NH4OAc led to oligomeric alkaloids, but at high dilution a dimer was obtained whose structure was formally that of a Diels-Alder adduct between racemigerine and a dihydropyridine. These biomimetic semisyntheses were analyzed in terms of reaction mechanisms and the relative paucity of known plant PMTAs in comparison with the multitudinous occurrence of their presumed iridoid glycoside precursors.
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PMID:Pyridine monoterpene alkaloid formation from iridoid glycosides. A novel PMTA dimer from geniposide. 898 52

Rice straw pretreated with liquid anhydrous ammonia was hydrolyzed with cellulase, cellobiase, and hemicellulase. Ammonia-processing conditions were 1.5 g of NH3/g of dry matter, 85 degrees C, and several sample moisture contents. There were four ammonia addition time (min)-processing time (min) combinations. Sugars produced were analyzed as reducing sugars (dinitrosalicylic acid method) and by high-performance liquid chromatography. Monomeric sugars increased from 11% in the nontreated rice straw to 61% of theoretical in treated rice straw (79.2% conversion as reducing sugars). Production of monosaccharides was greater at higher moisture content and was processing time dependent. Glucose was the monosaccharide produced in greater amounts, 56.0%, followed by xylose, arabinose, and fructose, with 35.8, 6.6, and 1.4%, respectively.
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PMID:Enzymatic hydrolysis of ammonia-treated rice straw. 1272 82

Due to its low digestibility in the small intestine, a major fraction of the polyol isomalt reaches the colon. However, little is known about effects on the intestinal microflora. During two 4-week periods in a double-blind, placebo-controlled, cross-over design, nineteen healthy volunteers consumed a controlled basal diet enriched with either 30 g isomalt or 30 g sucrose daily. Stools were collected at the end of each test phase and various microbiological and luminal markers were analysed. Fermentation characteristics of isomalt were also investigated in vitro. Microbiological analyses of faecal samples indicated a shift of the gut flora towards an increase of bifidobacteria following consumption of the isomalt diet compared with the sucrose diet (P<0.05). During the isomalt phase, the activity of bacterial beta-glucosidase decreased (P<0.05) whereas beta-glucuronidase, sulfatase, nitroreductase and urease remained unchanged. Faecal polyamines were not different between test periods with the exception of cadaverine, which showed a trend towards a lower concentration following isomalt (P=0.055). Faecal SCFA, lactate, bile acids, neutral sterols, N, NH3, phenol and p-cresol were not affected by isomalt consumption. In vitro, isomalt was metabolized in several bifidobacteria strains and yielded high butyrate concentrations. Isomalt, which is used widely as a low-glycaemic and low-energy sweetener, has to be considered a prebiotic carbohydrate that might contribute to a healthy luminal environment of the colonic mucosa.
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PMID:Effect of isomalt consumption on faecal microflora and colonic metabolism in healthy volunteers. 1644 15

The aim of the present study was to determine the effects of dietary administration of a fructooligosaccharide preparation rich in kestose and nestose on growth performance and gastrointestinal parameters in young turkeys. The kestose and nestose preparation was obtained through bioconversion of sucrose using fungi fructosyl transferase and contained in DM 39.9% of kestose, 17.6% of nystose, as well as 26.5% of glucose and 14.7% of sucrose. Three dietary levels of the sum of kestose and nystose (0.3, 0.6, and 1.2%) were fed to growing turkeys for 8 wk. When compared with the control treatment, addition of the kestose and nestose preparation had no effect on feed intake, feed conversion, and BW. The kestose and nestose-supplemented diet, especially the medium level of kestose and nystose, influenced microbial metabolism, especially in the ceca. Compared with the control group, the medium level of kestose and nestose decreased relative weight of gizzard (from 18.67 to 16.51 g/kg of BW) and weight of small intestine tissue (from 23.3 to 19.6 g/kg of BW) and increased weight of ceca digesta (from 3.51 to 4.77 g/kg of BW) as well as activities of microbial beta-glucosidase (an increase from 0.22 to 0.38 U/g) and alpha-galactosidase (an increase from 0.90 to 1.61 U/g), pH of digesta (a decrease from 6.13 to 5.79), concentration of NH3 (an increase from 0.60 to 0.98 mg/g), and concentration of total short-chain fatty acids (an increase from 81.1 to 107.7 micromol/g) in the cecal digesta. A high content of kestose and nestose in the diet caused a decrease in ileal and cecal pH (to 5.42 and 5.49, respectively).
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PMID:Effect of a kestose and nystose preparation on growth performance and gastrointestinal tract function of turkeys. 1749 83