Glucose oxidase (GOD) is an important industrial enzyme with many potential applications. In order to increase the production and productivity of GOD by recombinant Pichia pastoris GS115, we investigated the feeding strategies of mixed carbon sources during induction phase, based on results of the optimization of initial cell and methanol concentration on GOD production. The optimal initial cell and methanol concentration were 100 g/L and 18 g/L. During induction phase, the mixed-carbon-sources strategies showed that glycerol, sorbitol or mannitol co-feeding with methanol could enhance GOD production. With mannitol co-feeding (20:1(W/W)), the maximum GOD production and maximum GOD productivity reached 711.3 U/mL and 4.60 U/(mL x h) after an induction period of 156 h. Compared to the control, the enhancements of GOD production and productivity were 66.3% and 67.9%, respectively. Meanwhile, we found an appropriate mannitol co-feeding strategy that would not inhibit the expression of promote. The activity of alcohol oxidase was 8.8 U/g, which was enhanced by 69.2% compared to the control (5.2 U/g). We can use the same optimization process to improve the production of other proteins from recombinant Pichia pastoris by changing the fermentation parameters.
Carbon ; metabolism ; Fermentation ; Glucose Oxidase ; biosynthesis ; Glycerol ; metabolism ; Industrial Microbiology ; Mannitol ; metabolism ; Methanol ; metabolism ; Pichia ; metabolism ; Sorbitol ; metabolism

Conducting polymers have stable long-chain structure and good electrical conductivity. They have been used in various types of biosensors because of their excellent characteristics of the immobilization and electrical signal transmission. In recent years, researchers mainly study on improving its micro-nano structures and its signal conductivity to enhance its effect on the enzyme immobilization and signal conductive properties. This paper reviews firstly the application of conducting polymer on enzyme-immobilized glucose biosensor and the new technologies and methods in this field. This paper also points out the future application of conducting polymers in enzyme immobilization and biosensor preparation areas.
Biosensing Techniques ; methods ; trends ; Blood Glucose ; metabolism ; Electric Conductivity ; Enzymes, Immobilized ; Glucose Oxidase ; metabolism ; Nanostructures ; Polymers ; chemistry

To enhance the production of glucose oxidase by recombinant Pichia pastoris, two strategies were developed, which were namely co-feeding of methanol and sorbitol and co-expressing of the protein disulfide isomerase (PDI) and Vitreoscialla hemoglobin (VHb). The volumetric activity reached 456 U/mL by using the strain X33/pPIC9k-GOD, in 5 liter fermentator, with the co-feeding of methanol and sorbitol, it was 0.2 fold higher than that only feeding by methanol. The improved strain was obtained by co-expressing PDI-VHb with GOD. While fermented in a 5 liter fermentator by feeding methanol and sorbitol, the activity of the improved strain reached 716 U/mL with a yield of 7 400 mg/L total soluble protein concentration. These results indicated that heterologous protein expression level can be enhanced by optimizing fermentation condition and co-expression molecular chaperon in Pichia pastoris.
Bioreactors ; Fermentation ; Glucose Oxidase ; biosynthesis ; Methanol ; Pichia ; metabolism ; Recombinant Proteins ; biosynthesis ; Sorbitol

BACKGROUND: Commutable reference materials (RMs) are suitable for end-users for evaluating the metrological traceability of values obtained using routine measurement systems. We assessed the performance of 6 routine measurement systems with validated secondary RMs. METHODS: We tested the homogeneity, stability, and commutability of 5 minimally processed human serum pools according to the standard guidelines. The serum pools were assigned values as per the reference procedure of the United States Centers for Disease Control and were used to evaluate the trueness of results from 6 commercial measurement systems based on enzymatic methods: 3 glucose oxidase (GOD) and 3 hexokinase (HK) methods. RESULTS: The prepared RMs were validated to be sufficiently homogenous, stable, and commutable with the patient samples. Method bias varied for different systems: GOD01, -0.17 to 2.88%; GOD02, 1.66 to 4.58%; GOD03, -0.17 to 3.14%; HK01, -3.48 to -0.85%; HK02, -3.83 to -0.11%, and HK03, -1.82 to -0.27%. CONCLUSIONS: We observed that the prepared serum glucose RMs were qualified for trueness assessment. Most of the measurement systems met the minimal quality specifications.
Blood Chemical Analysis/instrumentation/*standards ; Blood Glucose/*analysis ; Glucose Oxidase/metabolism ; Hexokinase/metabolism ; Humans ; Reagent Kits, Diagnostic ; Reference Standards ; Regression Analysis

The L-gulono-gamma-lactone oxidase gene (Gulo) encodes an essential enzyme in the synthesis of ascorbic acid from glucose. On the basis of previous findings of bone abnormalities in Gulo-/- mice under conditions of ascorbic acid insufficiency, we investigated the effect of ascorbic acid insufficiency on factors related to bone metabolism in Gulo-/- mice. Four groups of mice were raised for 4 weeks under differing conditions of ascorbic acid insufficiency, namely, wild type; ascorbic acid-sufficient Gulo-/- mice, 3-week ascorbic acid-insufficient Gulo-/- mice, and 4-week ascorbic acid-insufficient Gulo-/- mice. Four weeks of ascorbic acid insufficiency resulted in significant weight loss in Gulo-/- mice. Interestingly, average plasma osteocalcin levels were significantly decreased in Gulo-/- mice after 3 weeks of ascorbic acid insufficiency. In addition, the tibia weight in ascorbic acid-sufficient Gulo-/- mice was significantly higher than that in the other three groups. Moreover, significant decreases in trabecular bone volume near to the growth plate, as well as in trabecular bone attachment to the growth plate, were evident in 3- or 4-week ascorbic acid-insufficient Gulo-/-. In summary, ascorbic acid insufficiency in Gulo-/- mice results in severe defects in normal bone formation, which are closely related to a decrease in plasma osteocalcin levels.
Animals ; Ascorbic Acid* ; Down-Regulation* ; Glucose ; Growth Plate ; L-Gulonolactone Oxidase ; Metabolism ; Mice ; Osteocalcin* ; Osteogenesis* ; Plasma ; Tibia ; Weight Loss

OBJECTIVE: To investigate the mechanism of high glucose affecting the apoptosis of schwann cells through Nox4 NADPH oxidase. METHODS: The schwann cells of newborn Wistar rats were cultured in vitro. The cultured cells were divided into four groups: control group, high-glucose group, NOX4 siRNA group and control siRNA group (n=10). The WST-1 method was used to detect the cell vitality, and the DCFH-DA method was used to detect the contents of intracellular reactive oxygen free radicals (ROS). Nox4 and Caspase3 mRNA expressions were detected by real-time fluorescence quantitative RT-PCR. Nox4 and Caspase3 protein expressions were determined by Western blot. RESULTS: High glucose culture up-regulated Nox4 mRNA and protein expressions of schwann cells, decreased activity of schwann cells, increased intracellular ROS content, and promoted apoptosis by increasing Caspase3 mRNA and protein expressions. NOX4 siRNA blocked the accumulation of ROS in the high glucose cultured schwann cells, and reduced the damage of glucose on cell viability, by inhibiting NOX4 gene expression. NOX4 siRNA also reduced cell apoptosis by down-regulating Caspase3 mRNA and protein expressions. CONCLUSION Nox4 was involved in the hyperglycemic-induced apoptosis of schwann cells through ROS. The regulation of Nox4 expression or function might be a new way to treat diabetic peripheral neuropathy.
Animals ; Apoptosis ; Caspase 3 ; metabolism ; Cells, Cultured ; Culture Media ; Glucose ; NADPH Oxidase 4 ; metabolism ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Schwann Cells ; cytology ; metabolism

It was expected that recombinant Aspergillus niger glucose oxidase could be expressed in Trichoderma reesei with stable activity. T. reesei CBHI promoter--CBHI ss. gene--A. niger glucose oxidase gene--T. reesei CBHI terminator--A. nidulans gpd promoter--E. coli Hygromycin B phosphotransferase gene--A. nidulans trpC terminator--pUC19 (pCBHGOD) vector was constructed in E. coli DH5alpha by PCR application and gene cloning methods. T. reesei QM9414 protoplast was transformed by T. reesei CBHI promoter-CBHI ss. Gene--A. niger glucose oxidase gene--T. reesei CBHI terminator-A. nidulans gpd promoter--E. coli Hygromycin B phosphotransferase gene--A. nidulans trpC terminator linear DNA fragment (CBHGOD fragment) that was made by digestion of pCBHGOD with Kpn I. T. reesei mutant clone with homologous recombinant A. niger glucose oxidase gene was selected by PCR method. Recombinant glucose oxidase was produced by mutant T. reesei strain under induction of wheat straw for 5 days. Recombinant glucose oxidase molecular mass was showed the same as native A. niger glucose oxidase standard from Sigma company by Western blot analysis. Recombinant glucose oxidase activity was 25u/mL in medium. The yield was 0.5 g/L in comparison with Sigma company glucose oxidase standard. There was no recombinant GOD degradation during Trichoderma reesei cultivation that was showed in Western blot analysis. Trichoderma reesei has capability to be a new recombinant host for Aspergillus niger GOD production.
Aspergillus niger ; enzymology ; genetics ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Fungal Proteins ; genetics ; metabolism ; Glucose Oxidase ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Trichoderma ; genetics ; metabolism

This study was designed to test the effect of Korean traditional tea materials on oxygen-free radical metabolism in lead (Pb) -administered rats. Male rats were divided into normal, Pb-control (Pb-Con) and Pb-water extract of green tea (Camellia sinensis; GT) , persimmon leaf (Diospyros kaki; PL) , safflower seed (Carhamus tinctorius: SS) , Du-Zhong (Eucommia ulmoides; EU) groups, respectively. Pb intoxication was induced by administration of lead acetate (25 mg/kg. B.W., oral) weekly. The extract was administered based on 1.26 g of raw material/kg B.W./day for 4 weeks. When the GT, PL, SS and EU were supplemented to the Pb-administered rats, hepatic lipid peroxide levels were significantly lower compared to the Pb-Con group. Hepatic cytochrom P-450 content and aminopyrine N-demethylase activity was lower in the Pb-Con group than in the normal group, whereas xanthine oxidase activity was significantly elevated in Pb-administered rats. The water extract of GT, PL, SS and EU supplementation attenuated changes in enzyme activities generating reactive oxygen species in the liver. Hepatic superoxide dismutase, catalase and glucose 6-phosphate dehydrogenase activities were significantly higher in the Pb-Con group than in the normal group, while monoamine oxidase activity also tended to increase in the Pb-administered rats. However, glutathione peroxidase and glutathione S-transferase activities, and glutathione content significantly decreased through Pb intoxication. The supplementation of GT, PL, SS and EU induced alleviation changes of hepatic antioxidant enzyme activity.
Aminopyrine N-Demethylase ; Animals ; Carthamus tinctorius ; Catalase ; Diospyros ; Eucommiaceae ; Glucose ; Glutathione ; Glutathione Peroxidase ; Glutathione Transferase ; Humans ; Liver ; Male ; Metabolism ; Monoamine Oxidase ; Oxidoreductases ; Oxygen* ; Rats* ; Reactive Oxygen Species ; Superoxide Dismutase ; Tea* ; Water* ; Xanthine Oxidase

BACKGROUND/OBJECTIVES: Mulberry leaves contain quercetin derivatives, which have the effects of reducing obesity and improving lipid and glucose metabolism in mice with obesity. It is not clear whether or not mulberry leaves can directly affect metabolic disorders, in the presence of obesity, because of the interaction between obesity and metabolic disorders. The aim of the current study was to assess the direct action of quercetin derivatives on metabolic disorders in non-obese conditions in short-term high-fat diet fed mice. MATERIALS/METHODS: C57BL/6N mice were fed a high-fat diet, supplemented with either 0% (control), 1%, or 3% mulberry leaf powder (Mul) or 1% catechin powder for five days. Anthropometric parameters and blood biochemistry were determined, and hepatic gene expression associated with lipid and glucose metabolism was analyzed. RESULTS: Body and white fat weights did not differ among the four groups. Plasma triglycerides, total cholesterol, and free fatty acids in the 1%, 3% Mul and catechin groups did not differ significantly from those of the controls, however, plasma glucose and 8-isoprostane levels were significantly reduced. Liver gene expression of gp91phox, a main component of NADPH oxidase, was significantly down-regulated, and PPAR-alpha, related to beta-oxidation, was significantly up-regulated. FAS and GPAT, involved in lipid metabolism, were significantly down-regulated, and Ehhadh was significantly up-regulated. Glucose-metabolism related genes, L-PK and G6Pase, were significantly down-regulated, while GK was significantly up-regulated in the two Mul groups compared to the control group. CONCLUSIONS: Our results suggest that the Mul quercetin derivatives can directly improve lipid and glucose metabolism by reducing oxidative stress and enhancing beta-oxidation. The 1% Mul and 1% catechin groups had similar levels of polyphenol compound intake (0.4 x 10(-5) vs 0.4 x 10(-5) mole/5 days) and exhibited similar effects, but neither showed dose-dependent effects on lipid and glucose metabolism or oxidative stress.
Adipose Tissue, White ; Animals ; Biochemistry ; Blood Glucose ; Catechin ; Cholesterol ; Diet, High-Fat ; Fatty Acids, Nonesterified ; Gene Expression* ; Glucose* ; Lipid Metabolism ; Liver ; Metabolism* ; Mice* ; Morus* ; NADPH Oxidase ; Obesity ; Oxidative Stress ; Plasma ; Quercetin* ; Triglycerides ; Weights and Measures

BACKGROUND/OBJECTIVES: Mulberry leaves contain quercetin derivatives, which have the effects of reducing obesity and improving lipid and glucose metabolism in mice with obesity. It is not clear whether or not mulberry leaves can directly affect metabolic disorders, in the presence of obesity, because of the interaction between obesity and metabolic disorders. The aim of the current study was to assess the direct action of quercetin derivatives on metabolic disorders in non-obese conditions in short-term high-fat diet fed mice. MATERIALS/METHODS: C57BL/6N mice were fed a high-fat diet, supplemented with either 0% (control), 1%, or 3% mulberry leaf powder (Mul) or 1% catechin powder for five days. Anthropometric parameters and blood biochemistry were determined, and hepatic gene expression associated with lipid and glucose metabolism was analyzed. RESULTS: Body and white fat weights did not differ among the four groups. Plasma triglycerides, total cholesterol, and free fatty acids in the 1%, 3% Mul and catechin groups did not differ significantly from those of the controls, however, plasma glucose and 8-isoprostane levels were significantly reduced. Liver gene expression of gp91phox, a main component of NADPH oxidase, was significantly down-regulated, and PPAR-alpha, related to beta-oxidation, was significantly up-regulated. FAS and GPAT, involved in lipid metabolism, were significantly down-regulated, and Ehhadh was significantly up-regulated. Glucose-metabolism related genes, L-PK and G6Pase, were significantly down-regulated, while GK was significantly up-regulated in the two Mul groups compared to the control group. CONCLUSIONS: Our results suggest that the Mul quercetin derivatives can directly improve lipid and glucose metabolism by reducing oxidative stress and enhancing beta-oxidation. The 1% Mul and 1% catechin groups had similar levels of polyphenol compound intake (0.4 x 10(-5) vs 0.4 x 10(-5) mole/5 days) and exhibited similar effects, but neither showed dose-dependent effects on lipid and glucose metabolism or oxidative stress.
Adipose Tissue, White ; Animals ; Biochemistry ; Blood Glucose ; Catechin ; Cholesterol ; Diet, High-Fat ; Fatty Acids, Nonesterified ; Gene Expression* ; Glucose* ; Lipid Metabolism ; Liver ; Metabolism* ; Mice* ; Morus* ; NADPH Oxidase ; Obesity ; Oxidative Stress ; Plasma ; Quercetin* ; Triglycerides ; Weights and Measures