Germination response of Bacillus subtilis PCI219 Spores to Caramelized Sugar and l-Asparagine

In presence of L-asparagine, effective substances in caramelized sugar were primarily glucose and fructose; isomerization of glucose/fructose was observed after autoclaving (120°C, 20 min, pH 7.2). Glucose and fructose were 63 to 24 in caramelized glucose and 12 to 44 in caramelized fructose. Apparent dissociation constants were: glucose 2.2 × 10^?4, fructose 1.3 × 10^?4, L-asparagine 2.2 × 10^?4. Hydroxymethylfurfural and maltol were not effective. Aging and heat activation of spores contributed to germination, especially for response to L-asparagine and/or fructose, but not glucose. The initiation mechanism was distinguishable from the L-alanine system in requirement for aging, heat activation of spores and response to inhibitor. L-AS-paragine could be partially replaced by NH₄⁺, but not by L-glutamine.     

Rag−mutations involved in glucose metabolism in yeast: Isolation and genetic characterization

Some natural isolates and many laboratory strains of the yeast Kluyveromyces lactis cannot grow on glucose when respiration is inhibited by antimycin A. The ability or inability to grow on glucose in the absence of mitochondrial respiration has been called Rag⁺ or Rag^? phenotype (resistance to antimycin on glucose, respectively). Rag^? strains, unable to grow on glucose in the presence of the respiratory drug, behave as if they were defective in fermentation. The Rag phenotype was first found to be determined by variant alleles of either of the two nuclear genes, RAG1 and RAG2, which code for a low-affinity glucose transport protein and for phosphoglucose isomerase, respectively. These findings suggested that the Rag^? phenotype can be used to obtain mutations of genes involved in glucose metabolism in K. lactis. We thus looked for other Rag^? mutants. Seventy-four mutants were isolated and genetically characterized. All of the mutations were nuclear recessive alleles, defining 11 new complementation groups, which we designate rag3 through rag13.     

Determination of sulphadimidine in animal feedstuffs by an enzyme-linked immunoassay

An enzyme immunoassay technique for the determination of sulphadimidine in animal feedstuffs has been developed. The antibody showed limited cross-reactivity with other drugs, including sulphonamides, used as feed additives. Using spiked samples recoveries of 80-88% were obtained. The limit of detection of the assay was 70 ng/g.     

Rapid Detection of Excessive CFU Counts of Enterobacteriaceae, S. aureus and Yeasts by Nitrate Reduction/Glucose Dissimilation (NGD) Monitoring in Selective Media

A technique was developed for the approximate selective estimation of CFU loads of thermotrophic Enterobacteriaceae and S. aureus in foods and meals, relying on rate of nitrate reduction and glucose dissimilation (NGD test) in lauryl sulfate nitrate glucose broth and modified liquid Baird Parker medium with nitrate and glucose added, respectively, both incubated at 42.5°C. Yeast CFU could be assessed similarly in oxytetracyclin gentamicin glucose broth at 30°C. The fate of nitrate and glucose was monitored by urinanalysis dip sticks. Response times were 7 and 2 hr for CFU levels of 10⁵ and 10⁸ g^?1, respectively, allowing feedback to production lines within one working day. The procedure requiring no other instrumentation than a centrifuge, also has been applied successfully as a field test procedure.     

Sulphonamide residues in milk of dairy cows following intravenous injection

An investigation was conducted into the elimination into milk of four sulphonamides (sulphadimidine, sulphamethoxypyridazine, sulphadimethoxine and sulphadoxine) after intravenous injections of drugs available in France. Sulphonamide determination in milk was performed using a high-performance liquid chromatography (HPLC) method with detection limit of 0.01 micrograms/ml. These results were used to determine the withdrawal times (two to six milkings) required for these drugs with a tolerance of 0.1 micrograms/ml as proposed by the European countries.     

Stability of sulphadimidine during raw fermented sausage preparation: reaction of sulphadimine with nitrite

 Raw fermented sausage was prepared from a dough to which sulphadimidine (SDM), a drug frequently used in animal husbandry, was added. With the aid of thermospray-mass spectroscopy further evidence was obtained that, during preparation, reactions with nitrite added to the dough resulted in the formation of desamino-SDM and 4-hydroxydesamino-SDM. An indication was obtained that traces of chlorodesamino-SDM were present in the brine, but this observation could not be established. Received: 22 March 1999 / Revised version: 10 May 1999     

Effects of bacterial cellulose on glucose metabolism in an in vitro chyme model and its rheological evaluation

Hyperglycaemia affects the health of people worldwide. The study investigated the effects of bacterial cellulose (BC) on glucose metabolism using an in vitro chyme model, including glucose adsorption, glucose diffusion, kinetics model of glucose and rheological properties of BC. The results indicated that BC exhibited significant inhibition of α-amylase in a dose-dependent manner (IC₅₀ = 7.86 mg mL⁻¹) and could significantly adsorb glucose by binding to the glucose molecules (4.11 ± 0.18 mmol g⁻¹) (P < 0.05). The BC chyme system was a non-Newtonian fluid showing shear thinning and has the characteristics of elastic solid. The diffusion behaviour of glucose in the BC chyme system conformed to first-order release kinetics model, indicating its inhibition of glucose diffusion by changing the rheological properties of chyme. This study provides a theoretical basis for dietary intervention and nutritional support for patients with hyperglycaemia.     

An optical flow injection analysis system for measurement of glucose in tomato

An optical flow injection analysis (FIA) system for glucose measurement in tomato was constructed by using a glucose oxidase (GOD) immobilized reactor and a photodiode sensor, a peristaltic pump and a personal computer. The GOD reactor was crammed with strip-shaped of a GOD immobilized membrane to an acrylic pipe. The GOD was immobilized on polytetrafluoroethylene membrane by crosslinking with glutaraldehyde. Hydrogen peroxide generated by the GOD reaction oxidized luminol to produce chemiluminescence in the presence of horseradish peroxide. The chemiluminescence was detected by using the photodiode. The glucose measurement system was calibrated with standard glucose solutions. The calibration range of the system for glucose was 2.0–100.0 mmol L⁻¹. Measurement time for every sample was within 3 min. Glucose concentrations of a fresh and processed tomato samples measured with this glucose measurement system could be evaluated rapidly and non-laboriously.     

Amino acid-dependent formation pathways of 2-acetylfuran and 2,5-dimethyl-4-hydroxy-3[2H]-furanone in the Maillard reaction

The formation pathways of two furanoids, 2-acetylfuran and 2,5-dimethyl-4-hydroxy-3[2H]-furanone (DMHF) were studied by GC–MS in the Maillard-type model system based on glucose and selected amino acids. The reaction was performed in 0.01 M phosphate buffer by heating a 1:1 mixture of [¹³C6] glucose and [¹²C6] glucose with amino acid. There is only one major formation pathway for DMHF in which the glucose carbon skeleton stayed intact. Formation pathways for 2-acetylfuran were more complicated. They formed either from glucose or from glucose and glycine. In the presence of glycine, the [C-5] unit of glucose combined with formaldehyde from glycine leads to 2-acetylfuran. For other amino acids, either cyclisation of intact glucose or recombination of glucose fragments can lead to 2-acetylfuran formation. These results indicate a competitive trend in controlling Maillard reaction. Therefore, besides changing Miallard reaction impact factors (temperature, time, pH etc.), inhibiting or preventing the competitive reaction cascade may direct desired pathways of Maillard reaction.     

Plasma potassium-lowering effect of oral glucose, sodium bicarbonate, and the combination thereof in healthy neonatal dairy calves

Hyperkalemia is a common complication in neonatal diarrheic dairy calves and is corrected by administration of glucose or sodium bicarbonate. Although the hypokalemic effect of glucose is well established in other species, controversial results are reported for sodium bicarbonate. Our objective was to study the effect and mechanism of action of glucose and sodium bicarbonate on the potassium homeostasis of healthy neonatal dairy calves. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2 L of NaHCO₃ (150 mmol/L), glucose (300 mmol/L), and glucose + NaHCO₃ solution (300 mmol/L + 150 mmol/L) in randomized order. Blood was obtained before treatment (T₀) and at 30-min intervals thereafter. Changes between each time point and T₀ were determined for all parameters. Urine was collected volumetrically to determine total renal potassium excretion over an 8-h posttreatment period. Plasma volume changes were extrapolated from changes in plasma protein concentration. Treatment and time effects were tested with repeated-measures ANOVA. Multivariate stepwise regression analysis using dummy variable coding was conducted to identify associations between changes in plasma potassium concentration ([K]) and changes in plasma glucose concentration ([glucose]), blood base excess, and plasma volume. Oral glucose and sodium bicarbonate treatments decreased [K] by 25 and 19%, respectively, whereas the combination of both compounds caused an intermediate [K] decline (22%). For the glucose treatment, the decline in [K] was only associated with changes in plasma [glucose] (partial R² = 0.19). In NaHCO₃-treated calves, [K] decline was associated with change of extracellular volume (partial R² = 0.31) and blood base excess (partial R² = 0.19). When glucose and NaHCO₃ were combined, [K] decline was associated with changes in plasma volume (partial R² = 0.30), BE (R² = 0.22), and [glucose] (partial R² = 0.03). Our results indicate that glucose lowers plasma [K] mainly through an insulin-dependent intracellular translocation of K, whereas NaHCO₃ causes hypokalemia through hemodilution followed by intracellular translocation of K caused by the strong ion effect. The combination of glucose and NaHCO₃ at the dosage used in this study does not have an additive hypokalemic effect. When combined, hemodilution and strong ion effect have the strongest effect on plasma [K], whereas the insulin-dependent effect of glucose appears to be blunted.     

Characterisation of an oleuropein degrading strain of Lactobacillus plantarum. Combined effects of compounds present in olive fermenting brines (phenols,glucose and NaCl) on bacterial activity

This study aims to examine the effects of glucose and NaCl on the ability of an oleuropein degrading strain of Lactobacillus plantarum, strain B21, to grow in the presence of oleuropein, its degradation product, hydroxytyrosol, and p-coumaric acid. Oleuropein (10 g litre⁻¹) and 2 g litre⁻¹ hydroxytyrosol combined with NaCl did not inhibit bacterial growth, whereas 1 g litre⁻¹ p-coumaric acid showed low inhibitory activity. This study also presents that bacterial β-glucosidase and esterase are involved in the breakdown of oleuropein. Oleuropein (10 g litre⁻¹) incorporated in the cultivation medium without glucose was completely degraded to derivative products within 20 days, whereas in the presence of glucose, at concentrations up to 50 g litre⁻¹ β-glucosidase activity was partially inhibited, and 30–70% of oleuropein residual content remained in the cultivation medium. Esterase activity involved in the second step of biodegradation process, was not influenced by glucose. Incorporation of glucose in the growth medium adversely affected the ability of L plantarum to break-down oleuropein. The findings of this study are significant since it could lead to the development of a new biotechnology for removing the bitter principle, oleuropein, from olives replacing the traditional alkali treatment used for debittering olives. © 1998 SCI.     

Some Properties of Whole-Cell Glucose Isomerase Immobilized in Polyacrylamide Gel by Radiation

The whole-cell glucose isomerase was immobilized by the method of block polymerization of acrylamide initiated by ⁶⁰Co irradiation. Some properties of immobilized glucose isomerase were studied under various reaction conditions, in respect of its use as industrial catalyst. It was established that Co²⁺ ions did not increase stability of the immobilized enzyme at pH above 8.0. The half-life of the immobilized glucose isomerase was found to be 24 days at 60°C.     

Enhancement of glucose production from maltodextrin hydrolysis by optimisation of saccharification process using mixed enzymes involving novel pullulanase

Pullulanase is important to enhance the production and quality of glucose from starch hydrolysis by mixed enzymatic saccharification. To improve glucose production, it would be necessary to manipulate the enzymatic saccharification process and conditions. For enzymatic saccharification involving the newly identified recombinant pullulanase, glucose, maltose and isomaltose were detected, and glucose was the main product from maltodextrin hydrolysis, with the dextrose equivalent value over 99.5%. During the saccharification process, there would be a balance between glucose and disaccharides due to enzymatic hydrolysis and its reverse reaction. With the optimised ratio of glucoamylase to pullulanase (50:1) and dry maltodextrin concentration (20%, w/w), the glucose content (DX) around 99% was obtained with the space‐time yield of 6 mg g^?1·h. After optimisation by orthogonal design and response surface methodology, the DX value of 99.35% was achieved with enzyme loading 75 U g^?1 at 55 °C and pH 4.5 for 36 h.     

Visible micro-Raman spectroscopy for determining glucose content in beverage industry

The potential of Raman spectroscopy with excitation in the visible as a tool for quantitative determination of single components in food industry products was investigated by focusing the attention on glucose content in commercial sport drinks. At this aim, micro-Raman spectra in the 600–1600 cm⁻¹ wavenumber shift region of four sport drinks were recorded, showing well defined and separated vibrational fingerprints of the various contained sugars (glucose, fructose and sucrose). By profiting of the spectral separation of some peculiar peaks, glucose content was quantified by using a multivariate statistical analysis based on the interval Partial Least Square (iPLS) approach. The iPLS model needed for data analysis procedure was built by using glucose aqueous solutions at known sugar concentrations as calibration data. This model was then applied to sport drink spectra and gave predicted glucose concentrations in good agreement with the values obtained by using a biochemical assay. These results represent a significant step towards the development of a fast and simple method for the on-line glucose quantification in products of food and beverage industry.     

Spectrophotometric determination of glucose in foods by flow injection analysis with an immobilized glucose oxidase reactor

 A stopped-flow injection analysis system for the determination of glucose is described, based on the iodometric measurement of hydrogen peroxide generated in a glucose oxidase reactor. The detection of the iodine–starch complex was carried out spectrophotometrically. The calibration curve was linear up to 2 mmol l^-1 glucose, with a correlation coefficient, r, of 0.9996. The relative standard deviation was 1.6% (n=5) for 1.0 mmol l^-1 glucose. A sample frequency of 25 samples h^-1 was achieved. This method was applied to the determination of glucose in fruit products and the results obtained using this method were in good agreement with those of a routine enzymatic method. A high dilution of the sample avoided interference from ascorbic acid. The enzyme reactor was stable for 1 month after 200 measurements with no loss of activity. Received: 22 March 1996     

Effects of monensin on glucose metabolism in transition dairy cows

Eight multiparous periparturient Holstein cows fitted with ruminal cannula were used in a split plot design to evaluate the effects of monensin on plasma glucose metabolism. Diets were top-dressed daily with 0 mg/cow of monensin (control) or 300 mg/cow of monensin (MON) both pre- and postpartum. Plasma glucose kinetic parameters on d ?13 ± 2.0 and 19 ± 1.6 relative to parturition were determined by using stable isotopes. Na-1-¹³C₃-Propionate (labeled propionate) was infused into the rumen to measure glucose synthesis originating from ruminal propionate, and U-¹³C-glucose (labeled glucose) was injected into the jugular vein to determine total glucose kinetics. A sampling period of 480 min following labeled glucose injection was implemented. A compartmental analysis was employed to determine steady state glucose kinetic parameters. To develop a steady state glucose model, the Windows version of SAAM software (WinSAAM) was used. A 4-compartment model was adequate to comprehensively describe plasma glucose metabolism. The main model compartments consisted of propionate and plasma glucose. The time frame of the 480-min sampling period post-tracer glucose infusion allowed accurate quantification of glucose metabolism. The model estimated that glucose input from sources other than ruminal propionate decreased with MON, from 2.26 to 1.09 g/min postpartum. Gluconeogenesis, expressed as the propionate contribution to the plasma glucose pool, increased in cows fed MON (22 vs. 31%), whereas glucose oxidation, expressed as the glucose disposal rate, significantly decreased (1.67 vs. 0.92 g/min). In conclusion, MON may improve the energy status of transition cows by (1) improving the efficiency of propionate to produce glucose and (2) decreasing glucose oxidation in body tissues.     

Stability of sulphadimidine during raw fermented sausage preparation

The transformation of sulphadimidine (SDM) during raw fermented suasage preparation was studied to elucidate the SDM decrease found in an earlier study. The raw fermented sausages were prepared from batters containing 1 and 10 mg [¹⁴C]-SCM kg^–1. The sausages and the brines were analysed using methods based on solid-phase extraction followed by HPLC combined with liquid scintillation counting. It can be concluded that the decrease in SDM level is mainly caused by (i) leaching into the brine (approx. 25%), (ii) transformation of SDM, possibly by reactions with components in the sausage or the brine, as the presence of five reaction products from SDM could be demonstrated, and (iii) formation of bound residues (approx. 20%).

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Stabilität von Sulfadimidin während der Rohwurstherstellung

Zusammenfassung Die Transformation von Sulfadimidin (SDM) während der Rohwurstherstellung wurde untersucht um die bei vorhergehenden Untersuchungen gefundene SDM-Abnahme zu klären. Die Rohwurst wurde mit 1 und 10 mg¹⁴C-SDM pro kg bereitet. Die Analyse der Wurst und Pökellake erfolgte Fest-Flüssig-Extraktion und HPLC, kombiniert mit Flüssigkeits-Szintillation-Zählung. Die Abnahme des SDM-Gehaltes in der Wurst wurde hauptsächlich verursacht durch: Auslaugen (ungefähr 25%), Reaktionen von SDM mit Komponenten in der Wurst und in der Lake (fünf Reaktionsprodukte wurden gefunden), und Bildung von gebundenen Rückständen (ungefähr 20%).

     

Sulphonamide residues in eggs following drug administration via the drinking water

The aim was to determine concentrations of sulphadimidine (SDM) and sulphadimethoxine (SDT) in eggs following oral administration through drinking water for 5 days (0.5g^-1 for SDT, 1 and 2gl^-1 for SDM). Residues of sulphonamides in albumen and yolk were monitored by high-performance liquid chromatography with UV detection. The limit of quantification was 0.005 μg g^-1 for the two egg components. The results indicate that 0.9-1.4% of the dose administered was deposited in eggs. Maximum concentrations in albumen were much higher than those in yolk. More than 75% of the overall sulphonamides detected in eggs was concentrated in the albumen. The residue levels declined below the limit of quantification within 12-20 days for albumen and 14-15 days for yolk after treatment was discontinued.     

Stimulation of glucose uptake by Musa sp. (cv. elakki bale) flower and pseudostem extracts in Ehrlich ascites tumor cells

BACKGROUND: Glucose uptake study plays a major role in diabetes research. Impaired glucose uptake has been implicated in the development of hyperglycemia during diabetes. Banana plant is known for its anti‐diabetic properties and our earlier report revealed that banana flower and pseudostem of Musa sp. cv. elakki bale is beneficial during diabetes in rat models. The present study was designed to evaluate the potential effect of banana flower and pseudostem extracts on glucose uptake in Ehrlich ascites tumor (EAT) cells using 2‐[N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)amino]‐2‐deoxy‐D ‐glucose (2‐NBDG), a fluorescent analogue of 2‐deoxyglucose. RESULTS: Methanol and aqueous extracts of banana flower and pseudostem were more potent in promoting glucose uptake in EAT cells, in comparison to acetone and ethanol extracts. At 20 µg dosage, highest net glucose uptake was observed in aqueous extracts of banana flower (18.17 ± 0.43 nmol L^?1) and pseudostem (19.69 ± 0.41 nmol L^?1). Total polyphenol content was higher in methanol (9.031 ± 0.036 g kg^?1) and aqueous (6.862 ± 0.024 g kg^?1) extracts of banana flower compared to pseudostem, which were 0.442 ± 0.006 and 0.811 ± 0.011 g kg^?1, respectively. CONCLUSION: Banana flower and pseudostem extracts are able to promote glucose uptake into the cells, presumably through glucose transporters 1 and 3, which could be beneficial in diabetes. Glucose uptake is likely promoted by phenolic acids besides other bioactives. It can be hypothesized that consumption of nutraceutical‐rich extract of banana flower and pseudostem could replace some amount of insulin being taken for diabetes. Copyright © 2011 Society of Chemical Industry     

Evaluation of glucose dose on intravenous glucose tolerance test traits in Holstein-Friesian heifers

Glucose metabolism in dairy and beef cattle has received considerable attention because balanced blood glucose is essential for numerous processes, such as milk production and general health. The glucose tolerance test measures the ability of an organism to regulate blood glucose levels. Glucose half-life time (GHLT) has high heritability and could serve as a potential parameter to breed for metabolic resistance. However, studies focusing on identification of an adequate glucose dose have not yet been conducted in cattle. The objective of this study was to analyze the effect of 5 different glucose doses (0.5, 1, 1.5, 2, and 3 g/kg of body weight^0.75) on intravenous glucose tolerance test (ivGTT) traits and insulin responses in nongestating heifers. A total of 150 tests were performed in 30 Holstein-Friesian heifers aged 13 to 15 mo. Blood samples were obtained every 7 min after glucose injection until min 63. Glucose traits and insulin parameters included blood serum glucose and insulin concentration at min 0 (basal concentration), min 7 to 21 (peak glucose and insulin concentration), and min 63 (last sampling) relative to glucose administration, glucose and insulin area under the curve (GAUC and IAUC), and GHLT estimated between min 14 and 42. Serum glucose and insulin concentrations were measured according to the hexokinase colorimetric method and radioimmunoassay, respectively. Generalized linear mixed model was used to test for significant differences in ivGTT traits, insulin responses, and glucose elimination rates (k) over time at different glucose doses. Maximum glucose and insulin concentrations at min 63 increased with higher glucose doses. Significantly lower GHLT were obtained at increasing glucose doses, whereas GAUC and IAUC were significantly higher at increasing doses. The k values were affected by glucose dose and by time interval. Glucose dose greatly affected most ivGTT traits, insulin responses, and glucose elimination rates. Therefore, researchers should standardize their methods to achieve repeatable results and use the same time points for GHLT calculation. Higher glucose doses (≥1.5 g/kg of body weight^0.75) triggered glucose concentrations above the glucose renal threshold during the initial 42 min, whereas the lowest glucose concentration failed to induce a maximum insulin response. Further research is necessary to determine an adequate dose inducing maximum insulin responses with minimum renal glucose losses.