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

Ethanol feeding to rats for 40 days enhanced (p < 0.001) the activities of alkaline phosphatase, sucrase, gamma-glutamyltransferase (GTP), and p-nitrophenyl (PNP)-beta-D-galactosidase (p < 0.05) with no change in leucine amino peptidase (LAP) and PNP-beta-D-glucosidase activities in intestine compared with control rats. The activities of alkaline phosphatase, sucrase, and GTP were diminished (p < 0.01) in ethanol-fed malnourished rats. There was no change in LAP activity, but the levels of glucosidase and galactosidase were elevated under these conditions. Brush-border sialic acid, fucose, hexose, and hexosamine contents were elevated in ethanol-fed protein-deficient animals. Ethanol administration to normally fed rats elevated the membrane sialic acid and hexose contents, reduced fucose content, and had no effect on brush-border hexosamine content compared with the control group. These results are in agreement with data on lectin binding to brush borders under these conditions. Alcohol ingestion reduced the incorporation of [14C]-glucosamine into brush borders in rats maintained on an 18% protein diet but augmented the incorporation of [14C]-glucosamine and [14C]-mannose in protein-malnourished membranes. These observations suggest that nutrition status influences the sensitivity of microvillus membrane glycosylation to ethanol feeding in rat intestine.
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PMID:Chronic ethanol feeding and microvillus membrane glycosylation in normal and protein-malnourished rat intestine. 142 85

Variations of glycoprotein components such as hexose, hexosamine, and sialic acid and lysosomal glycosidases such as beta-D-glucosidase, beta-D-galactosidase, and N-acetyl-beta-D-glucosaminidase were studied in the tumor tissue from various stages of cervical carcinoma of the uterus. Carbohydrate components of glycoprotein were found to be markedly reduced, and the reduction was very much significant in hexosamine and sialic acid in the advanced stages. Lysosomal glycosidases exhibited a significant increase, and among them N-acetyl-beta-D-glucosaminidase exhibited a prominent increase, in the advanced stages of cervical carcinoma of the uterus.
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PMID:Studies on variations of glycoproteins and lysosomal hydrolases in human uterine cervical carcinoma. 144 83

Phosphoglycans from the cell wall of many strains of Streptococci contain terminal carbohydrate units linked by phosphodiester bridges to other residues of the glycans. In the immune response to phosphoglycans, the terminal carbohydrate-phosphate moieties function as antigenic determinants and induce the synthesis of antibodies with specificity for the glycosyl-phosphoryl units. It has now been found that such terminal carbohydrate units can be removed by treatment of the glycans with appropriate glycosidases. Thus, an almond beta-glucosidase releases glucose from a streptococcal Group D phosphoglycan with beta-glucosyl phosphate units, a jack bean N-acetyl-beta-glucosaminidase releases N-acetylglucosamine from a streptococcal Group L phosphoglycan with N-acetyl-beta-glucosaminyl phosphate units, and a rice alpha-glucosidase releases glucose from a yeast phosphoglycan with alpha-glucosyl phosphate units. The glycosidases also hydrolyze the hexose phosphates of the proper anomeric configuration and structure. The preparations of glycosidases used in this study exhibit specificity for single types of carbohydrate residues and are devoid of phosphatase and phosphodiesterase activities. The glycosidases act on glycosyl-phosphoryl linkages by a stereospecific mechanism and can therefore be used for the determination of the anomeric configuration of glycosyl-phosphoryl units of complex carbohydrates.
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PMID:The determination of the anomeric configuration of glycosyl-phosphoryl linkages of immunogenic phosphoglycans. 240 37

The balanced polymorphism of glucose-6-phosphate dehydrogenase deficiency (G6PD-) is believed to have evolved through the selective pressure of malarial combined with consumption of fava beans. The implicated fava bean constituents are the hydroxypyrimidine glucosides vicine and convicine, which upon hydrolysis of their beta-O-glucosidic bond, became protein pro-oxidants. In this work we show that the glucosides inhibit the growth of Plasmodium falciparum, increase the hexose-monophosphate shunt activity and the phagocytosis of malaria-infected erythrocytes. These activities are exacerbated in the presence of beta-glucosidase, implicating their pro-oxidant aglycones in the toxic effect, and are more pronounced in infected G6PD- erythrocytes. These results suggest that G6PD- infected erythrocytes are more susceptible to phagocytic cells, and that fava bean pro-oxidants are more efficiently suppressing parasite propagation in G6PD- erythrocytes, either by directly affecting parasite growth, or by means of enhanced phagocytic elimination of infected cells. The present findings could account for the relative resistance of G6PD- bearers to falciparum malaria, and establish a link between dietary habits and malaria in the selection of the G6PD- genotype.
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PMID:Resistance of glucose-6-phosphate dehydrogenase deficiency to malaria: effects of fava bean hydroxypyrimidine glucosides on Plasmodium falciparum growth in culture and on the phagocytosis of infected cells. 871 Apr 17

Liposomes loaded with the nonionic iodinated contrast agent iodixanol were injected i.v. into monkeys, rats, and dogs, and liver samples were analyzed by HPLC and mass spectrometry. Two metabolites (M1 and M2), with UV spectra identical to those of the iodixanol isomers (exo and endo) and with a mass increase of 162 compared with iodixanol, were detected. Incubations of iodixanol-liposomes or iodixanol in rat liver homogenates resulted in large amounts of iodixanol metabolites, whereas no metabolites were formed in other organ or tissue homogenates. Four groups of unidentified HPLC peaks were detected: M1 and M2 with a relative retention similar to the metabolite peaks of the in vivo samples, and in addition the minor M3 and M4. UV spectrum analysis indicated that M1 and M3 were structurally related to the iodixanol exo-isomer, whereas M2 and M4 were related to the endo-isomer. Mass spectrometry techniques indicated that the metabolites were conjugates containing one or two hexose residues, which by carbohydrate analysis and experiments with concanavalin A-Sepharose and alpha- and beta-glucosidase were shown to be glucose residues bound to iodixanol through O-alpha1-glycoside-like linkages. Metabolites with similar mass increments also were detected for several other nonionic contrast agents after in vitro incubations in liver homogenates. In conclusion, M1 and M3 are conjugates of the iodixanol exo-isomer with one and two glucose adducts, respectively. M2 and M4 are similar conjugates of the iodixanol endo-isomer. This is the first report on hepatic biotransformation of this class of X-ray contrast agents.
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PMID:Biotransformation of nonionic X-Ray contrast agents In vivo and In vitro. 1049 49

The production of cellulases on minimal medium in the edible mushroom Agaricus bisporus is regulated by the carbon source: induced by cellulose and repressed by glucose. In order to isolate cellulose-growth specific sequences, a cDNA library from A. bisporus using suppression subtractive hybridization (SSH) was constructed. Northern blot analysis indicated that a high level of enrichment was achieved; 183 clones were isolated. A preliminary screen with cellulose-specific genes of A. bisporus (cel1, cel2, cel3 and cel4) using Southern hybridization resulted in 28 clones to be cel3, and 5 clones were cel2. The remaining 144 clones were sequenced. Partial sequences of the following genes were found: a beta-glucosidase homologue of the blvk gene of Kluyveromyces marxianus; a cellulase homologue of an endoglucanase (avicellase III) of Aspergillus aculeatus, four different xylanases homologue of the xyn genes of different fungi, and one hexose transporter homologue to the hxtA gene of Aspergillus parasiticus. The apparent full-length of two hydrophobins homologue to the abh3 gene of A. bisporus and one histone homologue to the h2a gene of Aspergillus niger were also found. The remaining sequences did not have homology to any known genes.
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PMID:Efficient isolation of genes differentially expressed on cellulose by suppression subtractive hybridization in Agaricus bisporus. 1282 11

MacQuillan, Anthony M. (University of Wisconsin, Madison) and Harlyn O. Halvorson. Metabolic control of beta-glucosidase synthesis in yeast. J. Bacteriol. 84:23-30. 1962-The hybrid Saccharomyces fragilis x S. dobzhanskii produced a constitutive beta-glucosidase when grown in succinate synthetic medium. Upon addition of beta-glucosides, thio-beta-glucosides, or low concentrations of glucose, a further induction of enzyme synthesis was observed. Studies with other sugars revealed some specificity in response to hexose induction. Phenyl-thio-beta-d-glucoside did not affect constitutive synthesis nor induction by glucosides, thio-glucosides, or glucose. Repression of beta-glucosidase synthesis is brought about by high concentrations of glucose and other carbon compounds. Preinduction does not confer resistance to catabolic repression of enzyme synthesis; this leads to the conclusion that two sites of control for beta-glucosidase synthesis are present in yeast. Multiplicity of control is further suggested from: (i) the properties of the inducing system; (ii) semiconstitutive nature of enzyme synthesis; (iii) the repression of constitutive synthesis by glucose; (iv) the elevated derepressed rates of enzyme synthesis after glucose inhibition; and (v) the selection of a family of low constitutive mutants with variable inducibility.
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PMID:Metabolic control of beta-glucosidase synthesis in yeast. 1446 63

Concentrations of cytokinin-like compounds were measured in root tips of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) collected in spring. Cytokinin bases and ribosides were estimated by radioimmunoassay after purification by immunoaffinity (zeatin riboside and isopentenyladenosine antibodies coupled to cellulose gel) and high performance liquid chromatography. Cytokinin glucosides were similarly analyzed in root extracts treated with beta-glucosidase and octadecyl-silica column chromatography in conjunction with immunoaffinity purification. The identity of predominant cytokinins obtained after enzymatic degradation was confirmed by gas chromatography-mass spectrometry. Each of the observed cytokinin bases and ribosides seemed to have a corresponding hexose conjugate form. Total quantity of cytokinin glucosides was twice that of cytokinin bases and ribosides, and the major compound was isopentenyladenosine hexose conjugate.
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PMID:Evidence of cytokinin bases, ribosides and glucosides in roots of Douglas-fir, Pseudotsuga menziesii. 1497 99

The streptococcal group E cell wall polysaccharide antigen was extracted from strain K129 cells with hot trichloroacetic acid and purified. It contained rhamnose and glucose in a 2:1 molar ratio, 2% protein, 1% phosphorus, and was free of muramic acid and glycerol. No type polysaccharide antigen was present. The reaction of specific group E rabbit antiserum with the polysaccharide was effectively inhibited by d-glucose and beta-glucosides such as 1-methyl-beta-d-glucose, cellobiose, and gentiobiose. The 1-methyl-alpha-d-glucose was one-half as effective as the beta isomer. l-Rhamnose and N-acetyl-d-glucosamine were ineffective. Partial acid hydrolysis of the antigen followed by chromatographic separation of the oligosaccharides resulted in the isolation and analysis of five fractions. These fractions were di-, tri-, and tetrasaccharides. A study of these fractions by chemical analysis, reduction with borohydride, inhibition of the antigen-antibody reaction, release of glucose by beta-glucosidase, and other evidence indicate that beta-d-glucose is the immunodominant sugar in the antigen. A glucose-rhamnose trisaccharide (1:2 molar ratio) was the most effective inhibitor of the precipitin reaction; the glucose was readily released by beta-glucosidase, and one-half of the rhamnose was reduced with borohydride. This trisaccharide is considered to be a repeating unit in the native polysaccharide and probably has the following structure: O-beta-d-glucosyl-(1-2)-O-alpha-l-rhamnosyl- (1-4)-l-rhamnose. A glucose-rhamnose disaccharide in which the hexose and pentose are linked as in the trisaccharide was an effective inhibitor of the precipitin reaction. Strain K129 cells do not appear to contain a type polysaccharide antigen.
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PMID:Chemical structure and immunological specificity of the streptococcal group e cell wall polysaccharide antigen. 1655 32

Sorghum is a tropical grass grown primarily in semiarid and drier parts of the world, especially areas too dry for corn. Sorghum production also leaves about 58 million tons of by-products composed mainly of cellulose, hemicellulose, and lignin. The low lignin content of some forage sorghums such as brown midrib makes them more digestible for ethanol production. Successful use of biomass for biofuel production depends on not only pretreatment methods and efficient processing conditions but also physical and chemical properties of the biomass. In this study, four varieties of forage sorghum (stems and leaves) were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy and X-ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and the enzymatic hydrolysis process. Forage sorghums with a low syringyl/guaiacyl ratio in their lignin structure were easy to hydrolyze after pretreatment despite the initial lignin content. Enzymatic hydrolysis was also more effective for forage sorghums with a low crystallinity index and easily transformed crystalline cellulose to amorphous cellulose, despite initial cellulose content. Up to 72% hexose yield and 94% pentose yield were obtained using modified steam explosion with 2% sulfuric acid at 140 degrees C for 30 min and enzymatic hydrolysis with cellulase (15 filter per unit (FPU)/g cellulose) and beta-glucosidase (50 cellobiose units (CBU)/g cellulose).
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PMID:Evaluation and characterization of forage Sorghum as feedstock for fermentable sugar production. 1875 81


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