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Results for “Methylglucosides”

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At least 19 recordsLinked to original sources
PubMed2004

Chemoenzymatic synthesis of sugar-containing biocompatible hydrogels: crosslinked poly(beta-methylglucoside acrylate) and poly(beta-methylglucoside methacrylate).

Sugar-containing biocompatible hydrogels were synthesized chemoenzymatically by the following two steps: 1. lipase-catalyzed esterification of beta-methylglucoside with acrylic acid/methacrylic acid/vinyl acrylate/vinyl methacrylate in solvent as well as solvent-free process for the formation of sugar-containing monomers; and 2. polymerization process by free-radical polymerization with and without a crosslinker, ethylene glycol dimethacrylate (EGDMA). The solvent-free process resulted in an initial reaction rate approximately 1.5-2 times faster than that of the solvent process along with a complete consumption of beta-methylglucoside during the alcoholysis. The presence of pendant vinyl groups in beta-methylglucoside acrylate (MGAA) and beta-methylglucoside methacrylate (MGMAA) was confirmed by (1)H/(13)C NMR analysis, whereas the successful polymerization with the consumption of the vinyl groups was confirmed by Fourier transform infrared spectroscopy and (13)C NMR spectra. The surfaces of both poly(MGAA) and poly(MGMAA) were analyzed using scanning electron microscopy. The increased contents of EGDMA resulted in a higher tensile strength as well as a reduced swelling ratio of poly(MGAA) and poly(MGMAA). The swelling exponents were within the range of 0.53 and 0.98. In vitro cytotoxicity tests by MTT assay exhibited >90% cell viability in the poly(MGAA) and poly(MGMAA) without EGDMA, whereas a significantly decreased cell viability was observed for those with EGDMA.

Acrylates↗
PubMed2004

Enzymatic esterification of beta-methylglucoside with acrylic/methacrylic acid in organic solvents.

The enzymatic esterifications of beta-methylglucoside with acrylic acid/methacrylic acid were carried out using Novozym 435. t-Butanol indicating the highest conversion value was determined as an optimal solvent. The molar ratio (beta-methylglucoside:acids) of 1:15 was most favorable to the esterification. The enzyme concentration of 5% (w/v), and the temperature (50 degrees C for beta-methylglucoside:acrylic acid, 45 degrees C for beta-methylglucoside:methacrylic acid) resulted in the highest final conversion. Beta-methylglucoside of 60gl(-1) was found to be most effective in terms of short reaction time as well as product concentrations. Under these conditions, the maximum conversions for the esterification of beta-methylglucoside with acrylic acid and beta-methylglucoside with methacrylic acid were 59.3% after 12h and 71.3% after 72h, respectively. The structural analysis of the products was performed by FT-IR spectroscopy and (1)H NMR.

Acrylates↗
PubMed1971

Efflux and the steady state in alpha-methylglucoside transport in Escherichia coli.

Efflux and the steady state in a group translocation system, the alpha-methylglucoside (alphaMG) transport system, were investigated. The maximum intracellular level of alpha-methylglucoside is a function of a steady state. There is no inhibition of alphaMG influx as the intracellular pool of alphaMG, and alpha-methylglucoside-6-phosphate (alphaMGP) rises. This steady state has three components: alphaMG influx, action of an alphaMGP phosphatase, and alphaMG efflux. The phosphatase is the rate-limiting step (half-time = 5.0 min); thus, the true efflux rate (half-time = 2.0 min) cannot be simply measured from the kinetics of alphaMG loss from the cell. Under our steady-state conditions the percentage of intracellular radioactivity present as alphaMGP was 71%. Under conditions of zero influx, after an efflux of 12 min the percentage present as alphaMGP fell to 55%. However, when fluoride was present during the efflux period, the percentage of the sugar as alphaMGP increased to about 85%. Fluoride greatly inhibits both influx and phosphatase activity (half-time = 50 min). The efflux of alphaMG from the cell is apparently also fluoride-sensitive but to a lesser extent (half-time = 4.1 min). These data are summarized in a model describing the three components of the steady-state and effect of fluoride.

Azides↗
PubMed1983

Phosphoenolpyruvate-dependent phosphorylation of alpha-methylglucoside in Streptococcus sanguis ATCC 10556.

Spontaneous mutants defective in some undefined membrane components of the phosphoenolpyruvate:glucose phosphotransferase system were isolated by plating cells of Streptococcus sanguis ATCC 10556 onto an agar containing lactose and 10 mM 2-deoxyglucose. Toluenized cells of these mutants were defective in their ability to catalyse the phosphoenolpyruvate-dependent phosphorylation of 2-deoxyglucose but were still able to phosphorylate alpha-methylglucoside. The phosphorylation of alpha-methylglucoside was essentially dependent on phosphoenolpyruvate and required the presence of both soluble and membrane components. It was concluded that S. sanguis possessed two different phosphoenolpyruvate:glucose phosphotransferase systems.

Deoxyglucose↗
PubMed1985

Effect of 2-deoxyglucose, alpha-methylglucoside, and glucosamine on aflatoxin production by Aspergillus parasiticus.

The effects of 2-deoxyglucose (2-DOG), alpha-methylglucoside (alpha-MG), and glucosamine (GA) on aflatoxin production by Aspergillus parasiticus were studied using conidia-initiated and replacement cultures. In conidia-initiated, 2-DOG, alpha-MG, and GA supported varying amounts of growth when employed as sole carbon sources. In both conidia-initiated and replacement cultures, 2-DOG, but not alpha-MG nor GA, as sole carbon sources support toxin formation. None of the compounds inhibited aflatoxin production when used in combination with glucose. It appears that neither 2-DOG, alpha-MG, nor GA can be considered nonmetabolizable analogs of glucose in A. parasiticus.

Aflatoxins↗
PubMed1981

alpha-Methylglucoside satisfies only Na+-dependent transport system of intestinal epithelium.

The unidirectional influx of alpha-methylglucoside (alpha-MG) by isolated chicken intestinal epithelial cells is 98% inhibited by phlorizin. The remaining 2% of the total influx occurs in the absence of Na+, is not sensitive to phloretin, and is equal to the diffusional entry rate for 2-deoxyglucose. The glucoside is much more strongly accumulated (75-fold) than 3-O-methylglucose (3-OMG) (10-fold). Inhibitors of the serosal sugar carrier (phloretin, cytochalasin B, theophylline, and flavanoids) do not enhance alpha-MG accumulation. It is concluded that the glycoside is not a substrate for the intestinal serosal transport system. Steady-state gradients of the sugar can be represented accurately by a concentrative, phlorizin-sensitive system that is opposed by a diffusional efflux process.

3-O-Methylglucose↗
PubMed1977

[The alpha-methylglucoside transport in Escherichia coli K12 cells].

The transport of alpha-methylglucoside (MG) in the wild type cells of Escherichia coli K12 and the isogenic mutant strains, defective in the activity of phosphoenolpyruvate: sugar phosphotransferase system components was studied. It was shown that the enzyme IIB' in the absence of enzyme I and HPr is able to transport MG into the cells by a "facilitated" diffusion mechanism. Compounds which dissipate the energy of membrane protone potential such as NaN3, carbonylcyanide-m-chlorophenylhydrasone, dicyclohexylcarbodiimide, enhance the utilization of MG by the wild-type cells. However, the cells retaining intact enzyme IIB' but deficient in the phospho approximately HPr-generating system, were not sensitive to the action of poisons. The cells possessing the intact phospho HPr-generating system and inactive enzyme IIB' are also unaffected by the poisons. It seems that these results do not confirm the hypothesis of the direct delta mu H+ involvement in the regulation of transmembrane phosphorylation. The hypothesis is postulated that the energy metabolism inhibitors influence the phosphatase activity of factor III of the phosphotransferase system. The present data are well explained by this hypothesis.

Biological Transport↗
PubMed1984

[Comparative genetics of yeasts. XXII. The determination of alpha-methylglucoside fermentation by the maltose genes MAL6c2 and malx in the offspring of Saccharomyces cerevisiae N. C. Y. C. 74 strain].

In offsprings of N.C.Y.C. 74, maltose regulatory constitutive MAL6C2 mutation controls alpha-methylglucoside (alpha-mgl) fermentation in the presence of MALx. MAL6C2 MALx system described by ten Berge et al, is analogous in function (polymeric interaction) to, at least, one MGLa gene from the system of complementary alpha-mgl genes MGLa MGLb MGLc identified by ten Berge. Suppressor malx mutation inhibits both the maltose and alpha-mgl activity of MAL6C2 allele. A brief review on participation of maltose genes in alpha-mgl fermentation is presented.

Alleles↗
PubMed1980

[Alpha-methylglucoside transmembrane phosphorylation and regulation of the beta-galactoside permease activity in E. coli K12].

The interaction between alpha-methylglucoside (MeGlc) and beta-galactoside transport systems in E. coli K12 was studied. It was shown that an addition of MeGlc to bacterial cells leads to repression of [14C] lactose accumulation and o-nitrophenyl-beta-D-galactopyranoside (NO2PheGal) hydrolysis. The mutational damage of one of the components of the MeGlc transport system is accompanied by elimination of the glucoside inhibitory action. Intracellular MeGlcP and GlcP lower the efficiency of the transmembraneous transfer of beta-galactosides. The data obtained suggest that repression of the beta-galactoside permease activity during transport of the MeGlc is a result of two processes: i.e. phosphorylation-coupled translocation of MeGlc and intracellular accumulation of MeGlcP. An assumption on the intramembraneous interaction of enzyme IIGlc with beta-galactoside permease is made.

Bacterial Proteins↗