By virtue of nicotinic acid as precursor compound,N saccinimidylnicotinizute has been synthesized through eletrophilic reaction and then esterified,one kind of conjugate reagent adapted to all kinds of protein can be ...By virtue of nicotinic acid as precursor compound,N saccinimidylnicotinizute has been synthesized through eletrophilic reaction and then esterified,one kind of conjugate reagent adapted to all kinds of protein can be obtained.Moreover,a quick and convenient way of labell antibody has been established,combining this conjugate reagent with the technique of the fixed phrase separation.The rate of its protein labell thus reached could be over 30% averagely.展开更多
The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to ded...The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory.展开更多
AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A contr...AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. RESULTS: Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. CONCLUSION: Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.展开更多
Escherichia coli BW25113 was metabolically engineered for CoQ10 production by replacing ispB with ddsA from Gluconobacter suboxydans.Effects of precursor balance and reduced nicotinamide-adenine dinucleotide phosphate...Escherichia coli BW25113 was metabolically engineered for CoQ10 production by replacing ispB with ddsA from Gluconobacter suboxydans.Effects of precursor balance and reduced nicotinamide-adenine dinucleotide phosphate （NADPH） availability on CoQ10 production in E.coli were investigated.The knockout of pykFA along with pck overexpression could maintain a balance between glyceraldehyde 3-phosphate and pyruvate,increasing CoQ10 production.Replacement of native NAD-dependent gapA with NADP-dependent gapC from Clostridium acetobutylicum,together with the overexpression of gapC,could increase NADPH availability and then enhanced CoQ10 production.Three effects,overexpressions of various genes in CoQ biosynthesis and central metabolism,different vectors and culture conditions on CoQ10 production in E.coli,were all investigated.The investigation of different vectors indicated that low copy number vector may be more beneficial for CoQ10 production in E.coli.The recombinant E.coli （△ispB：：ddsA,△pykFA and △gapA：：gapC）,harboring the two plasmids encoding pck,dxs,idi and ubiCA genes under the control of PT5 on pQE30,ispA,ddsA from Gluconobacter suboxydans and gapC from Clostridium acetobutylicum under the control of PBAD on pBAD33,could produce CoQ10 up to 3.24 mg·g-1 dry cell mass simply by changing medium from M9YG to SOB with phosphate salt and initial culture pH from 7.0 to 5.5.The yield is unprecedented and 1.33 times of the highest production so far in E.coli.展开更多
Alcoholism is a major health problem in the United States and worldwide,and alcohol remains the single most significant cause of liver-related diseases and deaths.Alcohol is known to influence nutritional status at ma...Alcoholism is a major health problem in the United States and worldwide,and alcohol remains the single most significant cause of liver-related diseases and deaths.Alcohol is known to influence nutritional status at many levels including nutrient intake,absorption,utilization,and excretion,and can lead to many nutritional disturbances and deficiencies.Nutrients can dramatically affect gene expression and alcohol-induced nutrient imbalance may be a major contributor to pathogenic gene expression in alcohol-induced liver disease(ALD).There is growing interest regarding epigenetic changes,including histone modifications that regulate gene expression during disease pathogenesis.Notably,modifications of core histones in the nucleosome regulate chromatin structure and DNA methylation,and control gene transcription.This review highlights the role of nutrient disturbances brought about during alcohol metabolism and their impact on epigenetic histone modifications that may contribute to ALD.The review is focused on four critical metabolites,namely,acetate,S-adenosylmethionine,nicotinamide adenine dinucleotide and zinc that are particularly relevant to alcohol metabolism and ALD.展开更多
Reactive oxygen species （ROS） attack guanine bases in DNA easily and form 8-hydroxydeoxyguanosine （8-OHdG）, which can bind to thymidine rather than cytosine, based on which, the level of 8-OHdG is gen- erally rega...Reactive oxygen species （ROS） attack guanine bases in DNA easily and form 8-hydroxydeoxyguanosine （8-OHdG）, which can bind to thymidine rather than cytosine, based on which, the level of 8-OHdG is gen- erally regarded as a biomarker of mutagenesis conse- quent to oxidative stress. For example, higher levels of 8-OHdG are noted in Helicobacter pylori-associated chronic atrophic gastritis as well as gastric cancer. However, we have found that exogenous 8-OHdG can paradoxically reduce ROS production, attenuate the nuclear factor-KB signaling pathway, and ameliorate the expression of proinflammatory mediators such as interleukin （IL）-I, IL-6, cyclo-oxygenase-2, and induc- ible nitric oxide synthase in addition to expression of nicotinamide adenine dinucleotide phosphate oxidase （NOX）-I, NOX organizer-1 and NOX activator-1 in vari- ous conditions of inflammation-based gastrointestinal （GI） diseases including gastritis, inflammatory bowel disease, pancreatitis, and even colitis-associated carci- nogenesis. Our recent finding that exogenous 8-OHdG was very effective in either inflammation-based or oxidative-stress-associated diseases of stress-related mucosal damage has inspired the hope that synthetic 8-OHdG can be a potential candidate for the treatment of inflammation-based GI diseases, as well as the pre- vention of inflammation-associated GI cancer. In this editorial review, the novel fact that exogenous 8-OHdG can be a functional molecule regulating oxidative- stress-induced gastritis through either antagonizing Rac-guanosine triphosphate binding or blocking the signals responsible for gastric inflammatory cascade is introduced.展开更多
AIM:To evaluate the effect of autoclaved diet on the jejunum neurons of the myenteric plexus of rats during their growth.METHODS:The experimental groups were made up of rats going through weaning whose mothers receive...AIM:To evaluate the effect of autoclaved diet on the jejunum neurons of the myenteric plexus of rats during their growth.METHODS:The experimental groups were made up of rats going through weaning whose mothers received either an autoclaved or a non-autoclaved diet during gestation and lactation,and rats that were fed the same diet as their mothers during the post-weaning period.In order to measure the neurons'body profile and to quantify the number of neurons per area,preparations were stained by the nicotinamide adenine dinucleotide-diaphorase method.RESULTS:No significant changes were observed in rats'body weight or in the number of neurons regardless of the diet used(P>0.05) .There was a decrease in the jejunum-ileum length in rats treated with an autoclaved diet(P<0.05) .An increase in the neuronal cross-sectional area was seen in rats that had received the autoclaved diet,an effect that was significant for animals undergoing weaning.In addition,all observed factors showed significant differences when related to the age of the animals.CONCLUSION:The autoclaved diet did not alter the quantity of neurons,but increased their cell body area,suggesting changes similar to those observed in protein deficiency.展开更多
Objective: The elevated incidence of obesity has been paralleled with higher risks of breast cancer. High adiposity increases leptin secretion from adipose tissue, which in turn increases cancer cell proliferation. Th...Objective: The elevated incidence of obesity has been paralleled with higher risks of breast cancer. High adiposity increases leptin secretion from adipose tissue, which in turn increases cancer cell proliferation. The interplay between leptin and estrogen is one of the mechanisms through which leptin influences breast carcinogenesis. An unbalanced estrogen metabolism increases the formations of catechol estrogen quinones, DNA adducts, and cancer mutations. This study aims to investigate the effect of leptin on some estrogen metabolic enzymes and DNA adduction in breast cancer cells.Methods: High performance liquid chromatography(HPLC) was performed to analyze the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine. Reporter gene assay, real time reverse transcription polymerase chain reaction(real time RT-PCR), and Western blot were used to assess the expression of estrogen metabolizing genes and enzymes: Cytochrome P-4501B1(CYP1B1), Nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase1(NQO1), and Catechol-O-methyl transferase(COMT).Results: Leptin significantly increased the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine.Furthermore, leptin significantly upregulated CYP1B1 promoter activity and protein expression. The luciferase promoter activities of NQO1 and m RNA levels were significantly reduced. Moreover, leptin greatly reduced the reporter activities of the COMT-P1 and COMT-P2 promoters and diminished the protein expression of COMT.Conclusions: Leptin increases DNA adduct levels in breast cancer cells partly by affecting key genes and enzymes involved in estrogen metabolism. Thus, increased focus should be directed toward leptin and its effects on the estrogen metabolic pathway as an effective approach against breast cancer.展开更多
We report a general method to graft aromatic molecules onto graphene thin film electrodes through a simple immersion process. Large-area electroactive graphene thin films grafted with methylene blue （MB） have been d...We report a general method to graft aromatic molecules onto graphene thin film electrodes through a simple immersion process. Large-area electroactive graphene thin films grafted with methylene blue （MB） have been developed as electrocatalytic electrodes for the oxidation of β-nicotinamide adenine dinucleotide （NADH）. The oxidation of NADH starts from -0.08 V （vs. Ag/AgC1） at the graphene-MB thin film electrodes, showing a decrease of 530 mV in overpotential compared to a Ti metal electrode. The graphene-MB thin films have promising applications in biosensors and biofuel cells due to their ability to promote NADH electron transfer reaction.展开更多
文摘By virtue of nicotinic acid as precursor compound,N saccinimidylnicotinizute has been synthesized through eletrophilic reaction and then esterified,one kind of conjugate reagent adapted to all kinds of protein can be obtained.Moreover,a quick and convenient way of labell antibody has been established,combining this conjugate reagent with the technique of the fixed phrase separation.The rate of its protein labell thus reached could be over 30% averagely.
基金Supported by the Ministry of Education of Henan Province in China (2011A610004)
文摘The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory.
文摘AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. RESULTS: Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. CONCLUSION: Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.
基金Supported by the National Natural Science Foundation of China（30970089 200876181 20831006） the Natural Science Foundation of Guangdong Province（9351027501000003） the Project of Science and Technology of Guangdong Province（2007A010900001）
文摘Escherichia coli BW25113 was metabolically engineered for CoQ10 production by replacing ispB with ddsA from Gluconobacter suboxydans.Effects of precursor balance and reduced nicotinamide-adenine dinucleotide phosphate （NADPH） availability on CoQ10 production in E.coli were investigated.The knockout of pykFA along with pck overexpression could maintain a balance between glyceraldehyde 3-phosphate and pyruvate,increasing CoQ10 production.Replacement of native NAD-dependent gapA with NADP-dependent gapC from Clostridium acetobutylicum,together with the overexpression of gapC,could increase NADPH availability and then enhanced CoQ10 production.Three effects,overexpressions of various genes in CoQ biosynthesis and central metabolism,different vectors and culture conditions on CoQ10 production in E.coli,were all investigated.The investigation of different vectors indicated that low copy number vector may be more beneficial for CoQ10 production in E.coli.The recombinant E.coli （△ispB：：ddsA,△pykFA and △gapA：：gapC）,harboring the two plasmids encoding pck,dxs,idi and ubiCA genes under the control of PT5 on pQE30,ispA,ddsA from Gluconobacter suboxydans and gapC from Clostridium acetobutylicum under the control of PBAD on pBAD33,could produce CoQ10 up to 3.24 mg·g-1 dry cell mass simply by changing medium from M9YG to SOB with phosphate salt and initial culture pH from 7.0 to 5.5.The yield is unprecedented and 1.33 times of the highest production so far in E.coli.
基金Supported by The National Institute of Alcohol Abuse and Alcoholism grants AA014371 (to Joshi-Barve S),AA015970 (to McClain CJ), and Office of Dietary Supplements, NIH
文摘Alcoholism is a major health problem in the United States and worldwide,and alcohol remains the single most significant cause of liver-related diseases and deaths.Alcohol is known to influence nutritional status at many levels including nutrient intake,absorption,utilization,and excretion,and can lead to many nutritional disturbances and deficiencies.Nutrients can dramatically affect gene expression and alcohol-induced nutrient imbalance may be a major contributor to pathogenic gene expression in alcohol-induced liver disease(ALD).There is growing interest regarding epigenetic changes,including histone modifications that regulate gene expression during disease pathogenesis.Notably,modifications of core histones in the nucleosome regulate chromatin structure and DNA methylation,and control gene transcription.This review highlights the role of nutrient disturbances brought about during alcohol metabolism and their impact on epigenetic histone modifications that may contribute to ALD.The review is focused on four critical metabolites,namely,acetate,S-adenosylmethionine,nicotinamide adenine dinucleotide and zinc that are particularly relevant to alcohol metabolism and ALD.
基金Supported by A grant from the Ministry of Education and Science Technology,South Korea,No.2010-0002052
文摘Reactive oxygen species （ROS） attack guanine bases in DNA easily and form 8-hydroxydeoxyguanosine （8-OHdG）, which can bind to thymidine rather than cytosine, based on which, the level of 8-OHdG is gen- erally regarded as a biomarker of mutagenesis conse- quent to oxidative stress. For example, higher levels of 8-OHdG are noted in Helicobacter pylori-associated chronic atrophic gastritis as well as gastric cancer. However, we have found that exogenous 8-OHdG can paradoxically reduce ROS production, attenuate the nuclear factor-KB signaling pathway, and ameliorate the expression of proinflammatory mediators such as interleukin （IL）-I, IL-6, cyclo-oxygenase-2, and induc- ible nitric oxide synthase in addition to expression of nicotinamide adenine dinucleotide phosphate oxidase （NOX）-I, NOX organizer-1 and NOX activator-1 in vari- ous conditions of inflammation-based gastrointestinal （GI） diseases including gastritis, inflammatory bowel disease, pancreatitis, and even colitis-associated carci- nogenesis. Our recent finding that exogenous 8-OHdG was very effective in either inflammation-based or oxidative-stress-associated diseases of stress-related mucosal damage has inspired the hope that synthetic 8-OHdG can be a potential candidate for the treatment of inflammation-based GI diseases, as well as the pre- vention of inflammation-associated GI cancer. In this editorial review, the novel fact that exogenous 8-OHdG can be a functional molecule regulating oxidative- stress-induced gastritis through either antagonizing Rac-guanosine triphosphate binding or blocking the signals responsible for gastric inflammatory cascade is introduced.
基金Supported by The State of So Paulo Research Foundation (FAPESP),that partially funded this study
文摘AIM:To evaluate the effect of autoclaved diet on the jejunum neurons of the myenteric plexus of rats during their growth.METHODS:The experimental groups were made up of rats going through weaning whose mothers received either an autoclaved or a non-autoclaved diet during gestation and lactation,and rats that were fed the same diet as their mothers during the post-weaning period.In order to measure the neurons'body profile and to quantify the number of neurons per area,preparations were stained by the nicotinamide adenine dinucleotide-diaphorase method.RESULTS:No significant changes were observed in rats'body weight or in the number of neurons regardless of the diet used(P>0.05) .There was a decrease in the jejunum-ileum length in rats treated with an autoclaved diet(P<0.05) .An increase in the neuronal cross-sectional area was seen in rats that had received the autoclaved diet,an effect that was significant for animals undergoing weaning.In addition,all observed factors showed significant differences when related to the age of the animals.CONCLUSION:The autoclaved diet did not alter the quantity of neurons,but increased their cell body area,suggesting changes similar to those observed in protein deficiency.
基金supported by a grant from University of Texas Medical Branch National Institute of Environmental Health Sciences Center Pilot Project E506676
文摘Objective: The elevated incidence of obesity has been paralleled with higher risks of breast cancer. High adiposity increases leptin secretion from adipose tissue, which in turn increases cancer cell proliferation. The interplay between leptin and estrogen is one of the mechanisms through which leptin influences breast carcinogenesis. An unbalanced estrogen metabolism increases the formations of catechol estrogen quinones, DNA adducts, and cancer mutations. This study aims to investigate the effect of leptin on some estrogen metabolic enzymes and DNA adduction in breast cancer cells.Methods: High performance liquid chromatography(HPLC) was performed to analyze the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine. Reporter gene assay, real time reverse transcription polymerase chain reaction(real time RT-PCR), and Western blot were used to assess the expression of estrogen metabolizing genes and enzymes: Cytochrome P-4501B1(CYP1B1), Nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase1(NQO1), and Catechol-O-methyl transferase(COMT).Results: Leptin significantly increased the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine.Furthermore, leptin significantly upregulated CYP1B1 promoter activity and protein expression. The luciferase promoter activities of NQO1 and m RNA levels were significantly reduced. Moreover, leptin greatly reduced the reporter activities of the COMT-P1 and COMT-P2 promoters and diminished the protein expression of COMT.Conclusions: Leptin increases DNA adduct levels in breast cancer cells partly by affecting key genes and enzymes involved in estrogen metabolism. Thus, increased focus should be directed toward leptin and its effects on the estrogen metabolic pathway as an effective approach against breast cancer.
文摘We report a general method to graft aromatic molecules onto graphene thin film electrodes through a simple immersion process. Large-area electroactive graphene thin films grafted with methylene blue （MB） have been developed as electrocatalytic electrodes for the oxidation of β-nicotinamide adenine dinucleotide （NADH）. The oxidation of NADH starts from -0.08 V （vs. Ag/AgC1） at the graphene-MB thin film electrodes, showing a decrease of 530 mV in overpotential compared to a Ti metal electrode. The graphene-MB thin films have promising applications in biosensors and biofuel cells due to their ability to promote NADH electron transfer reaction.
