Amounts Of D-glucose Research Articles

Enzymatic hydrolysis of the gelatinous layer in tension wood of Salix varieties as a measure of accessible cellulose for biofuels

BackgroundSalix (willow) species represent an important source of bioenergy and offer great potential for producing biofuels. Salix spp. like many hardwoods, produce tension wood (TW) characterized by special fibres (G-fibres) that produce a cellulose-rich lignin-free gelatinous (G) layer on the inner fibre cell wall. Presence of increased amounts of TW and G-fibres represents an increased source of cellulose. In the present study, the presence of TW in whole stems of different Salix varieties was characterized (i.e., physical measurements, histochemistry, image analysis, and microscopy) as a possible marker for the availability of freely available cellulose and potential for releasing d-glucose. Stem cross sections from different Salix varieties (Tora, Björn) were characterized for TW, and subjected to cellulase hydrolysis with the free d-glucose produced determined using a glucose oxidase/peroxidase (GOPOD) assay. Effect of cellulase on the cross sections and progressive hydrolysis of the G-layer was followed using light microscopy after staining and scanning electron microscopy (SEM).ResultsTension wood fibres with G-layers were developed multilaterally in all stems studied. Salix TW from varieties Tora and Björn showed fibre G-layers were non-lignified with variable thickness. Results showed: (i) Differences in total % TW at different stem heights; (ii) that using a 3-day incubation period at 50 °C, the G-layers could be hydrolyzed with no apparent ultrastructural effects on lignified secondary cell wall layers and middle lamellae of other cell elements; and (iii) that by correlating the amount of d-glucose produced from cross sections at different stem heights together with total % TW and density, an estimate of the total free d-glucose in stems can be derived and compared between varieties. These values were used together with a literature value (45%) for estimating the contribution played by G-layer cellulose to the total cellulose content.ConclusionsThe stem section-enzyme method developed provides a viable approach to compare different Salix varieties ability to produce TW and thus freely available d-glucose for fermentation and biofuel production. The use of Salix stem cross sections rather than comminuted biomass allows direct correlation between tissue- and cell types with d-glucose release. Results allowed correlation between % TW in cross sections and entire Salix stems with d-glucose production from digested G-layers. Results further emphasize the importance of TW and G-fibre cellulose as an important marker for enhanced d-glucose release in Salix varieties.

STUDY OF METHOD OF PROCESSING CELLULOSIC AND LIGNIN-CONTAINING RAW MATERIALS USING CELLULOLYTIC ENZYMES

In the research the results of bioethanol and other valuable products formation are described during peat hydrolytic formation. The factors of cellulose-lignin raw materials (peat and wood sawdust) stability to the action of various hydrolyzing agents were determined. The obtained experimental data indicate the efficiency of peat and sawdust samples pre-treatment with H2SO4 (90 wt.%), which is expressed in the highest yield of reducing substances during hydrolysis of the samples, in comparison with the results obtained with H2SO4 pretreatment of a lower concentration. The article shows the results of cellulose-containing raw materials hydrolysis process study with various ways, including enzymatic treatment. Enzyme complex sample of Celloviridine, containing both exo-and endo-enzymes, was used. Qualitative and quantitative analysis of the cellulose-lignin-containing raw materials hydrolysis products was carried out using high-performance liquid chromatography. It was found that the maximum rate of glucose accumulation (the final product of the hydrolytic process of cellulose-lignin raw materials) was observed when using samples of peat and sawdust pretreated with H2SO4 (90wt.%). As a result of cellulosulignin raw material subsequent enzymatic hydrolysis, the amount of D-glucose in the hydrolyzate increased with the help of the Celloviridin preparation in comparison with its amount in the H2SO4 pretreatment. A comparative characterization of the raw material efficiency for the yield of the desired product - D-glucose is shown. In the process of combined hydrolysis of cellulose and lignin-containing raw materials the maximum yield of the monosaccharide was observed during the hydrolysis of peat samples. After appropriate neutralization the resulting hydrolysis solution can be used to produce bioethanol and bacterial biomass in the microbial synthesis of products used for animal feed, as well as for pharmaceutical practice.Forcitation:Lakina N.V., Doluda V.Yu., Sulman E.M., Shkileva I.P., Burmatova O.S. Study of method of processing cellulosic and lignin-containing raw materials using cellulolytic enzymes. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 78-83

Effect of D-glucose feeding on mortality induced by sepsis.

Sepsis is the life-threatening response to infection which can lead to tissue damage, organ failure, and death. In the current study, the effect of orally administered D-glucose on the mortality and the blood glucose level induced by D-Galactosamine (GaLN)/lipopolysaccharide (LPS)-induced sepsis was examined in ICR mice. After various amounts of D-glucose (from 1 to 8 g/kg) were orally fed, sepsis was induced by injecting intraperitoneally (i.p.) the mixture of GaLN /LPS. Oral pre-treatment with D-glucose dose-dependently increased the blood glucose level and caused a reduction of sepsis-induced mortality. The oral post-treatment with D-glucose (8 g/kg) up to 3 h caused an elevation of the blood glucose level and protected the mortality observed in sepsis model. However, D-glucose post-treated at 6, 9, or 12 h after sepsis induction did not affect the mortality and the blood glucose level induced by sepsis. Furthermore, the intrathecal (i.t.) pretreatment once with pertussis toxin (PTX; 0.1 µg/5 ml) for 6 days caused a reduction of D-glucose-induced protection of mortality and hyperglycemia. Furthermore, once the hypoglycemic state is continued up to 6 h after sepsis initiated, sepsis-induced mortality could not be reversed by D-glucose fed orally. Based on these findings, it is assumed that the hypoglycemic duration between 3 and 6 h after the sepsis induction may be a critical time of period for the survival. D-glucose-induced protective effect against sepsis-induced mortality appears to be mediated via activating PTX-sensitive G-proteins in the spinal cord. Finally, the production of hyperglycemic state may be critical for the survival against the sepsis-induced mortality.

Accumulation of d-glucose from pentoses by metabolically engineered Escherichia coli.

Escherichia coli that is unable to metabolize d-glucose (with knockouts in ptsG, manZ, and glk) accumulates a small amount of d-glucose (yield of about 0.01 g/g) during growth on the pentoses d-xylose or l-arabinose as a sole carbon source. Additional knockouts in the zwf and pfkA genes, encoding, respectively, d-glucose-6-phosphate 1-dehydrogenase and 6-phosphofructokinase I (E. coli MEC143), increased accumulation to greater than 1 g/liter d-glucose and 100 mg/liter d-mannose from 5 g/liter d-xylose or l-arabinose. Knockouts of other genes associated with interconversions of d-glucose-phosphates demonstrate that d-glucose is formed primarily by the dephosphorylation of d-glucose-6-phosphate. Under controlled batch conditions with 20 g/liter d-xylose, MEC143 generated 4.4 g/liter d-glucose and 0.6 g/liter d-mannose. The results establish a direct link between pentoses and hexoses and provide a novel strategy to increase carbon backbone length from five to six carbons by directing flux through the pentose phosphate pathway.

One-pot hydrothermal synthesis of MoS 2 nanosheets/C hybrid microspheres

Uniform MoS 2 nanosheets/C hybrid microspheres with mean diameter of 320 nm have been successfully synthesized via a facile one-pot hydrothermal route by sodium molybdate reacting with sulfocarbamide in d-glucose solutions. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). XRD patterns showed that the MoS 2 was kept as a two-dimensional nanosheet crystal and C was retained as amorphous even after their annealing treatment at 800 °C. TEM and SEM images indicated that the MoS 2 nanosheets were uniformly dispersed in the amorphous carbon. The experiment results also revealed that the appropriate amount of d-glucose had an obvious effect on the formation of uniform MoS 2 nanosheets/C hybrid microspheres. A possible formation process of MoS 2 nanosheets/C hybrid microspheres was preliminarily presented.

Lipase dissolution and stabilization in ether-functionalized ionic liquids

Ionic liquids (ILs) with various structures and properties have been extensively investigated in many biocatalytic reactions and processes. However, although hydrophobic ILs tend to stabilize the insoluble (suspended) enzymes, they usually have low hydrogen-bonding basicity with solutes, which limits the solubility of many substrates (such as D-glucose, ascorbic acid, and cellulose). In contrast, hydrophilic ILs (such as those based on chloride, acetate and dicyanamide) are able to dissolve many of these substances that are not quite soluble in common organic solvents. Unfortunately, enzymes are not always active in these hydrophilic media due to strong interactions (such as H-bonding) between proteins and ILs. To resolve this dilemma, we recently synthesized new acetate-based ILs carrying a long alkyloxyalkyl chain in their cations, and found that these ether-functionalized solvents are lipase-compatible and can dissolve considerable amounts of D-glucose and cellulose (Green Chem., 2008, 10, 696). In this study, we further observed that these ILs could dissolve high concentrations of lipase B from Candida antarctica (CALB) (> 5 mg/mL at 50 °C), as well as other substrates including amino acids and betulinic acid. Therefore, these novel media offer new opportunities for carrying out homogeneous enzymatic reactions, which is practically important for large substrate molecules. In this article, we further confirmed the lipase compatibility of these ILs through the transesterification between ethyl butyrate and 1-butanol. The second derivative infrared spectra of CALB suggest the conservation of secondary structures of proteins in these ILs. We further investigated these ether-functionalized ILs in two important biocatalytic reactions: enzymatic synthesis of methyl-phthalate of betulinic acid, and CALB-catalyzed synthesis of D-glucose fatty acid esters. These substrates are not very soluble in conventional organic solvents, but very soluble in ILs, which improved the catalytic efficiency of these reactions. Moderate to high conversions were achieved in both reactions.

Plasma D-Glucose, D-Fructose and Insulin Responses after Oral Administration of D-Glucose, D-Fructose and Sucrose to Normal Rats

Objective: To assess whether oral D-fructose modifies the plasma D-glucose and insulin responses to oral D-glucose administration in normal rats.Design: Oral D-glucose (1.7, 3.5, 6.9 or 13.9 μmol/g body weight), D-fructose (6.9 μmol/g), both D-glucose and D-fructose (1.7 or 3.5 μmol/g of each hexose) or sucrose (3.7 μmol/g) were administered intragastrically to overnight fasted rats and the plasma concentration of D-glucose, D-fructose and insulin measured over the ensuing 120 minutes. Control experiments were conducted after oral administration of H2O or saline.Results: The administration of D-fructose, given as the free hexose or as sucrose, instead of augmenting the plasma D-glucose concentration evoked by the concomitant administration of D-glucose, tended both to improve the insulin response of the pancreatic B-cell and to minimize hyperglycemia, when compared to the results of experiments including the administration of equimolar amounts of D-glucose alone. For instance, the area under the plasma D-glucose curve was comparable in the rats receiving both D-glucose and D-fructose (3.5 μmol/g of each hexose) and the rats receiving only D-glucose (3.5 μmol/g), averaging respectively 836 ± 32 and 850 ± 34 mM · min each. Likewise, the paired ratio between the areas under the plasma insulin and D-glucose curves, when corrected for the threshold concentration for the insulinotropic action of the hexose (2.05 ± 0.10 mM), averaged 44.3 ± 3.0 nmol/mol in the 16 rats receiving D-fructose alone, sucrose alone or both D-glucose and D-fructose, as compared to 37.7 ± 2.9 nmol/mol in the 22 rats receiving increasing amounts of D-glucose alone.Conclusions: The intake of D-fructose, as the free hexose or as sucrose, favours D-glucose homeostasis. This is likely to be attributable to the reciprocal effects of the aldose and ketose upon their respective phosphorylation by glucokinase in both hepatocytes and insulin-producing pancreatic islet cells.

Conformational stability of proteins and peptide-peptide interactions in the presence of carbohydrates

The denaturation temperatures and enthalpies of bovine pancreatic RNAase A in the presence of different amounts of D-glucose or its oligomers have been determined from DSC measurements and compared with literature results for other globular proteins in the presence of oligosaccharides or polyhydroxylated compounds. Both parameters increase almost proportionally for RNAase A at increasing sugar concentration (the denaturation appearing as a reversible, one-step process) and the evaluated Gibbs energy-temperature plots show an expansion of the stability range and an increase in relative stability. Isothermal measurements were also obtained by dilution-flow calorimetry to determine the virial coefficients of the excess enthalpies for aqueous solutions of some model peptides (N-acetylamides of simple amino acids) in the presence of l M D-glucose. These results provide an insight into the role of sugars in preventing peptide-peptide interactions.

Effect of medium-chain glycerides on the membrane transport of D-glucose and sulfanilic acid in the intestinal brush-border membrane vesicles.

To clarify the influence of medium-chain glycerides (MCG) on a biological membrane, we investigated the membrane transport of D-glucose and sulfanilic acid in the brush-border membrane (BBM) vesicles pretreated with MCG. The size distribution of the BBM vesicles determined by electron microscopic observation was not significantly different between the vesicles incorporated with MCG and those of the control. However, the amount of D-glucose taken up by the vesicles at an equilibrated stage (30 min) was significantly decreased in the MCG-treated ones based on unit content of protein. Based on these results we estimated the membrane transport of D-glucose and sulfanilic acid in consideration of vesiculation or filter-capturing efficiency in MCG-treated vesicles. The rates of Na+ gradient-independent D-glucose transport and sulfanilic acid transport were significantly greater in MCG-treated vesicles than in the control. On the other hand, the magnitude of overshooting effect in Na+ gradient-dependent uptake of D-glucose in MCG-treated vesicles was maintained similar to the control. Comparison of kinetic parameters for active D-glucose transport at different concentrations indicated that Km and Vmax were not significantly different between MCG-treated and the control vesicles. These results indicated that passive diffusion of D-glucose and sulfanilic acid was significantly increased but Na(+)-glucose cotransporter was not significantly changed by the incorporation of MCG in the intestinal BBM vesicles.

Untersuchungen über die Schleimpolysaccharide aus Lindenblüten

Linden flowers are known to contain considerable amounts of mucilage. Quantitative determinations of these water soluble polysaccharides were carried out by viscosimetric measurements. It was shown that the mucilage after total hydrolysis in trifluoracetic acid was composed of D-galactose, L-arabinose and L-rhamnose and minor amounts of D-glucose, D-mannose and D-xylose. The high percentage of uronic acid (52%) was due to the presence of both, D-galacturonic acid and D-glucuronic acid. Fractionation of the mucilage polysaccharides on DEAE-cellulose resulted in a separation of five distinct polysaccharide fractions, which showed different sugar compositions and uronic acid content. The homogeneity of the polysaccharide fractions 1-5 was further examined by high voltage electrophoresis and analytical ultracentrifugation.

The uptakein vitroof monosaccharides, disaccharide and nucleic acid precursors by adultDirofilaria immitis

The uptake of glucose, sucrose, thymidine and adenosine by adult male and female worms of Dirofilaria immitis was investigated using scintillation counting techniques. No evidence of L-glucose, sucrose and thymidine uptake was obtained. In contrast, large amounts of D-glucose and adenosine were taken up by both male and female worms.No demonstrable dye was found in the gut lumen of worms incubated in medium containing 1% (w/v) trypan blue for six hours.By exposing different portions of D. immitis adults to radioactively-labelled medium containing D-glucose or adenosine, a transcuticular uptake of these nutrients by the worms was demonstrated.

カツオ・マグロかん詰のかっ変（オレンジミート）防止 Ｉ 解凍および製造工程中のグリコーゲン分解物量の変化

The browning of canned skipjack and albacore is called “orange discoloration” and it is well-known that the appearance of orange discolored meat is particularly noted in brine frozen fish. It has been shown by YAMANAKA et al. that glucose-6-phosphate (G6P) is the sugar primarily responsible for orange discoloration. In this paper, changes in the amounts of glycolytic intermediates in skipjack meat during its canning process were examined in connection with the extent of the discoloration.The amounts of glycolytic intermediates in skipjack meat obtained from canning factories were 9-253mg/100g for glycogen, 8 ?? 319mg/100g for D-glucose, 22 ?? 229 mg/100g for G6P, and 237 ?? 858mg/100g for lactic acid.There existed a linear relation with a high correlation coefficient between the amount of D-glucose or G6P in defrozen meat and the intensity of orange discoloration. The most intense discoloration occurred in all skipjack meats with more than 150 ?? 200mg of G6P per 100g of meat.

Uptake of d-Glucose by Renal Tubule Membranes: I. EVIDENCE FOR TWO TRANSPORT SYSTEMS

Abstract d-[14C]Glucose was taken up by a cell-free, membrane-rich, particulate fraction prepared from isolated rabbit renal tubules by processes which showed temperature and phlorizin sensitivity, stereospecificity, sodium dependence, and saturability. The amount of d-glucose taken up and metabolized by the membrane preparation as well as the time course observed indicate that this uptake process represents transport into membrane-lined vesicles rather than binding to membrane fragments. Kinetic analyses in the presence and absence of sodium revealed that the uptake of d-glucose was mediated by two distinct systems: one with a high affinity and low capacity for glucose and a requirement for sodium ions; a second with low affinity and high capacity for glucose and no sodium requirement. Additional evidence for these two systems was obtained from experiments with other unlabeled sugars which showed qualitative and quantitative differences in inhibition of d-[14C]glucose uptake.

A Rapid Polarographic Microdetermination of Glucose with Glucose Oxidase

A rapid polarographic microdetermination of D-glucose with β-D-glucose oxidase in direct oxygen consumption mode is described. The apparatus composed of polarographic oxygen electrode, recorder (2 mV full scale), voltage prebox for increasing the sensitivity by cancelling unnecessary voltage of the output voltage of oxygen analyzer, and specially designed vial fixed on the magnetic stirrer. A trace amount of sodium azide was used to inhibit catalase contained in the biological sample and crude glucose oxidase. In this method, the relation between the amount of D-glucose and the amount of consumed oxygen gave a straight line at the range of 0.5 to 600 μg of D-glucose. The results obtained by this method on serum glucose with internal standard were enough consistent with those obtained by o-toluidine-borate method. The result on blood is obtainable within 5 min after a blood sample (5 μl) was collected from a patient.

Cell wall lipopolysaccharides from Neisseria catarrhalis

Lipopolysaccharides (LPS) prepared from N. catarrhalis cells were separated into a chloroform-soluble fraction (26%) and a chloroform-insoluble fraction (74%). Both LPS fractions contained D-glucose, D-galactose, D-glucosamine, galactosamine, lipid A, ethanolamine, fatty acids, acetyl, phosphate, and protein in approximately equal proportions. The lipid A moieties prepared from the two LPS fractions were also similar in composition to each other. The fatty acids and galactosamine of the LPS fractions were recovered quantitatively in their lipid A fractions. The major fatty acid component was β-hydroxylauric acid in contrast with β-hydroxymyristic acid, which is the major fatty acid component of the lipid A of N. perflava and other Gram-negative bacteria. The lipid A of N. catarrhalis also contained a considerable amount of D-glucose and D-galactose, which are not normal constituents of lipid A fractions. The presence of amino acids (ca. 2%) in all fractions suggested that proteins were an integral part of the LPS molecules. The absence of heptose and 3-deoxyoctulosonic acid (KDO) from the N. catarrhalis LPS shows that it lacks a lipopolysaccharide "core" structure similar to that present in the LPS of N. perflava; the polysaccharide part of the LPS molecule is also compositionally different from that of N. perflava. These differences may provide additional evidence to that already accumulated from other sources that N. catarrhalis is taxonomically a "false neisseria".

A novel method of determining the number-average degree of polymerization of linear maltodextrins and amylose

An enzymic method for determining the number-average degree of polymerization ( D P ¯ n ) of maltodextrins and amylose is described. In this technique, the D-glucans are treated with β-amylase under conditions in which enzymic degradation is complete, i.e., molecules having an even number of residues form maltose, and molecules having an odd number of residues yield maltose and one D-glucose unit. The amount of D-glucose is estimated by using glucose oxidase. The total concentration of the D-glucan itself is measured by use of amyloglucosidase. Hence, on the basis that the sample contains equal numbers of molecules having odd and even numbers of D-glucose residues, D P ¯ n can be calculated. Experimental conditions for this assay are discussed, and the accuracy of the technique has been confirmed by using ( a) pure maltodextrins, and ( b) synthetic mixtures of two degraded amyloses of D P ¯ n ca. 400 and 8. The method has been found to be applicable to linear amylose; D P ¯ n values greater than 1000 can be obtained to within 5%.

Induced Autolysis of Aspergillus oryzae ( A. niger group)

The examination of substances formed during induced autolysis by Aspergillus niger was continued in this work, which dealt in particular with carbohydrates. The autolysate contained a large amount of d -glucose (14 to 20% dry wt) and traces of glycolic aldehyde, dihydroxyacetone, ribose, xylose, and fructose. It also contained glycopeptides (about 10% dry wt), which were split from the cell wall during autolysis and which differed from one another in their level of polymerization and their composition. They were constituted by glucose and mannose, glucose and galactose, or mannose, glucose, and galactose (mannose being the most abundant in this case), and amino acids (chiefly alanine, serine, glutamic acid, and aspartic acid). During autolysis, only a part of the cell wall was dissolved, since it retained its shape. Upon further chemical hydrolysis, it produced mostly glucose and glucosamine, and smaller amounts of mannose, galactose, and amino acids. Presumably, glucomannoproteins and glucogalactoproteins were present in the intact cell as a macromolecular complex, constituting, together with chitin, the major part of the cell wall of Aspergillus .

THE POOL SIZE, TURNOVER RATE, AND OXIDATION RATE OF BODY GLUCOSE IN ANESTHETIZED WARM- AND COLD-ACCLIMATED RATS EXPOSED TO A WARM ENVIRONMENT

The size and space of the body glucose pool along with its turnover and oxidation rates have been measured in anesthetized 30° and 6 °C acclimated rats by a method involving continuous intravenous injection of small amounts of D-glucose uniformly labelled with C14and attainment of relatively constant specific activities of plasma glucose and respiratory CO2. Values of glucose pool space in warm-acclimated rats (essentially normal animals) were in accord with those found in the dog by a similar method. Results obtained on warm-acclimated rats indicated that previous published values of turnover and oxidation rates of glucose for normal rats were high by a factor of approximately 2 to 4. There was, however, close agreement between the values of turnover time of body glucose pool measured by the continuous infusion procedure and those obtained by others with the single intravenous or intraperitoneal injection procedure. In cold-acclimated rats, average absolute values of glucose pool size were significantly smaller than in warm-acclimated rats but the difference was lost when results were related to body weight. Small, non-significant differences in values of glucose pool size per 100 g body weight and in plasma glucose concentration combined to give a significantly larger glucose space in cold-than in warm-acclimated rats. Glucose turnover and oxidation rates, the ratio between these two quantities, and the proportion of respiratory CO2derived from glucose oxidation were not significantly different in the two groups of rats, thus indicating that cold acclimation is not associated with major alterations in glucose metabolism at least when studied on fully fed anesthetized animals at 30 °C.