21 results on '"Shaojun Yang"'
Search Results
2. Noni ( Morinda citrifolia L.) wine prevents the oxidative stress and obesity in mice induced by high‐fat diet
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Shaojun Yang, Xue Tang, Kai Zhang, Xiaojuan Li, Jun Meng, Yipin Lv, and Shuhua Ma
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Taste ,Antioxidant ,030309 nutrition & dietetics ,medicine.medical_treatment ,Biophysics ,Wine ,Diet, High-Fat ,Mice ,03 medical and health sciences ,0404 agricultural biotechnology ,medicine ,Animals ,Morinda ,Obesity ,Food science ,Noni juice ,Pharmacology ,0303 health sciences ,Vitamin C ,biology ,food and beverages ,04 agricultural and veterinary sciences ,Cell Biology ,biology.organism_classification ,Fruit wine ,040401 food science ,Oxidative Stress ,Polyphenol ,Food Science - Abstract
Noni (Morinda citrifolia L.) is rich in polyphenols, flavonoids, terpenoids, and iridoids. However, its bad taste and smell make noni fruit unsuitable for consumption. After fermentation, noni wine becomes free from the undesirable smell. Nevertheless, it is still unclear whether processed noni could retain its original nutrients and effects. Therefore, we conducted a series of evaluations on the nutritional composition and efficacy of noni wine. Our results showed that the polyphenol, flavonoid, and vitamin C contents in noni wine were 558.80, 234.42, and 0.30 mg/L, respectively. Our animal experiments showed that 40 ml kg-1 day-1 noni wine could reduce bodyweight, as well as the levels of body fat, serum triglycerides, total cholesterol, and low-density lipoprotein, while it simultaneously increased the amount of energy expenditure and activity, and improved the systemic antioxidant capacity in mice following a high-fat diet. The results of the gene expression and western blot analyses showed that 40 ml kg-1 day-1 noni wine could regulate the Nrf2 pathway and improve the antioxidant enzyme gene expression in mice maintained on a high-fat diet, thereby improving body lipid metabolism, reducing fatty acid synthesis, and promoting fatty acid β-oxidation. Our study indicated that drinking 40 ml kg-1 day-1 noni wine could effectively prevent high-fat diet-induced oxidative stress and obesity in mice. PRACTICAL APPLICATIONS: Noni fruit is rich in nutrients but its bad smell and hardship of processing make its commercialization difficult. Previous studies mainly focused on fresh noni juice and its primary processed products, while few noni products, of poor taste and low quality, are available in the market. Therefore, the fruit wine with both the nutritive values and the special flavor of noni has broad market prospects. Our work provides a valuable reference for the commercialization of noni wine.
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- 2020
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3. Quinone and nitrofurantoin redox cycling by recombinant cytochrome b5 reductase
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Yi-Hua Jan, Jason R. Richardson, Yun Wang, Karma C. Fussell, John T. Szilagyi, Jeffrey D. Laskin, Diane E. Heck, Debra L. Laskin, Vladimir Mishin, Shaojun Yang, and Lauren M. Aleksunes
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0301 basic medicine ,Free Radicals ,Cytochrome ,Toxicology ,Redox ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Oxygen Consumption ,Menadione ,Cytochrome b5 ,Benzoquinones ,Humans ,Heme ,Cytochrome b5 reductase ,Pharmacology ,Flavin adenine dinucleotide ,biology ,Recombinant Proteins ,Kinetics ,030104 developmental biology ,Nitrofurantoin ,Biochemistry ,chemistry ,Microsomes, Liver ,biology.protein ,Reactive Oxygen Species ,Oxidation-Reduction ,Cytochrome-B(5) Reductase ,NADP ,Drug metabolism - Abstract
NADH cytochrome b(5) reductase mediates electron transfer from NADH to cytochrome b(5) utilizing flavin adenine dinucleotide as a redox cofactor. Reduced cytochrome b(5) is an important cofactor in many metabolic reactions including cytochrome P450-mediated xenobiotic metabolism, steroid biosynthesis and fatty acid metabolism, hemoglobin reduction, and methionine and plasmalogen synthesis. Using recombinant human enzyme, we discovered that cytochrome b5 reductase mediates redox cycling of a variety of quinones generating superoxide anion, hydrogen peroxide, and, in the presence of transition metals, hydroxyl radicals. Redox cycling activity was oxygen-dependent and preferentially utilized NADH as a co-substrate; NADH was 5–10 times more active than NADPH in supporting redox cycling. Redox cycling activity was greatest for 9,10-phenanthrenequinone and 1,2-naphthoquinone, followed by 1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone (menadione), nitrofurantoin and 2-hydroxyestradiol. Using menadione as the substrate, quinone redox cycling was found to inhibit reduction of cytochrome b(5) by cytochrome b(5) reductase, as measured by heme spectral changes in cytochrome b(5). Under anaerobic conditions where redox cycling is inhibited, menadione had no effect on the reduction of cytochrome b(5). Chemical redox cycling by cytochrome b(5) reductase may be important in generating cytotoxic reactive oxygen species in target tissues. This activity, together with the inhibition of cytochrome b(5) reduction by redox-active chemicals and consequent deficiencies in available cellular cytochrome b(5), are likely to contribute to tissue injury following exposure to quinones and related redox active chemicals.
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- 2018
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4. Reduced graphene oxide-supported methylene blue nanocomposite as a glucose oxidase-mimetic for electrochemical glucose sensing
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Shaojun Yang, Shuyao Wu, Daliang Liu, Xi-Ming Song, and Qing Bo Meng
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Detection limit ,Nanocomposite ,biology ,Chemistry ,Graphene ,General Chemical Engineering ,Oxide ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Ascorbic acid ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,law ,Electrode ,biology.protein ,Glucose oxidase ,0210 nano-technology ,Methylene blue ,Nuclear chemistry - Abstract
In this paper, a hybrid nanocomposite (MB-rGO) was synthesized based on the π–π stacking interactions between methylene blue (MB) and reduced graphene oxide (rGO). The as-synthesized nanocomposite was characterized by SEM, TEM, XRD, FTIR, UV-vis and XPS spectra. UV-vis spectroscopy and electrochemical tests suggested the MB-rGO modified on the electrode exhibited glucose oxidase-mimetic catalytic activity towards glucose, and displayed excellent electrocatalytic performance for electrochemical detection of glucose with a wide linear range from 1.04 to 17.44 mM, a low detection limit of 45.8 μM and a large sensitivity of 13.08 μA mM−1 cm−2. The proposed glucose sensor also showed high stability, reproducibility and good abilities of anti-interference to dopamine, ascorbic acid and uric acid. Moreover, the modified electrode was used to determine glucose concentration in human blood serum samples with satisfactory results.
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- 2018
5. Early Secreted Antigen ESAT-6 of Mycobacterium Tuberculosis Promotes Apoptosis of Macrophages via Targeting the MicroRNA155-SOCS1 Interaction
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Ming Chen, Ya Shang, Wenbing Jiang, Fake Li, Shuangrong Jia, Shaojun Yang, Shaoli Deng, Kejun Zhang, and Kai Chang
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Physiology ,medicine.medical_treatment ,microRNA-155 ,Suppressor of Cytokine Signaling Proteins ,Apoptosis ,Biology ,lcsh:Physiology ,Cell Line ,Mycobacterium tuberculosis ,lcsh:Biochemistry ,Mice ,Immune system ,Antigen ,ESAT-6 ,medicine ,Animals ,Humans ,Tuberculosis ,SOCS1 ,TLR2 ,lcsh:QD415-436 ,Antigens, Bacterial ,lcsh:QP1-981 ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Macrophages ,Transcription Factor RelA ,Immunotherapy ,biology.organism_classification ,Molecular biology ,Recombinant Proteins ,Toll-Like Receptor 2 ,MicroRNAs ,Real-time polymerase chain reaction ,Cancer research ,Leukocytes, Mononuclear ,RNA Interference - Abstract
Background: The early secreted antigenic target 6-kDa protein (ESAT-6) of Mycobacterium tuberculosis (Mtb) not only acts as a key player for virulence but also exhibits a strong immunotherapeutic potential against Mtb. However, little is known about the molecular basis for its potential in immunotherapy. The present study was designed to unravel the role of miRNA-155 in ESAT-6-mediated enhancement of host immunity and apoptosis in macrophages. Methods: Lentivirus-mediated miR-155 sponge and miR-155 and SOCS1 overexpression vectors were developed in macrophages. TLR2- or p65-specific siRNA knockdown was employed to silence TLR2 or p65. Quantitative polymerase chain reaction and western blotting analyses were performed to determine mRNA and protein expression levels, respectively. Macrophage apoptosis was analyzed by flow cytometry. Results: ESAT-6 significantly increased miR-155 expression, which was dependent on TLR2/NF-κB activation in macrophages. Induced expression of miRNA-155 was required for the ESAT-6-mediated protective immune response and macrophage apoptosis. ESAT-6 promoted macrophage apoptosis by targeting the miR-155-SOCS1 pathway. The differential expression levels of TLR2, BIC, and SOCS1 were involved in regulating the immune response in human peripheral blood mononuclear cells of patients with active tuberculosis (TB) and latent TB (LTB). Conclusion: ESAT-6 promotes apoptosis of macrophages via targeting the miRNA155-SOCS1 interaction.
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- 2015
6. Diacetyl/L-Xylulose Reductase Mediates Chemical Redox Cycling in Lung Epithelial Cells
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Shaojun Yang, Jeffrey D. Laskin, Vladimir Mishin, Diane E. Heck, Debra L. Laskin, and Yi-Hua Jan
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0301 basic medicine ,Carbonyl Reductase ,Dehydrogenase ,Reductase ,Toxicology ,Cofactor ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Structure-Activity Relationship ,Menadione ,Humans ,L-xylulose reductase ,Lung ,chemistry.chemical_classification ,biology ,Dose-Response Relationship, Drug ,Molecular Structure ,Superoxide ,Quinones ,Epithelial Cells ,General Medicine ,030104 developmental biology ,Enzyme ,Biochemistry ,chemistry ,A549 Cells ,biology.protein ,Oxidation-Reduction ,Sugar Alcohol Dehydrogenases - Abstract
Reactive carbonyls such as diacetyl (2,3-butanedione) and 2,3-pentanedione in tobacco and many food and consumer products are known to cause severe respiratory diseases. Many of these chemicals are detoxified by carbonyl reductases in the lung, in particular, dicarbonyl/L-xylulose reductase (DCXR), a multifunctional enzyme important in glucose metabolism. DCXR is a member of the short-chain dehydrogenase/reductase (SDR) superfamily. Using recombinant human enzyme, we discovered that DCXR mediates redox cycling of a variety of quinones generating superoxide anion, hydrogen peroxide, and, in the presence of transition metals, hydroxyl radicals. Redox cycling activity preferentially utilized NADH as a cosubstrate and was greatest for 9,10-phenanthrenequinone and 1,2-naphthoquinone, followed by 1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone (menadione). Using 9,10-phenanthrenequinone as the substrate, quinone redox cycling was found to inhibit DCXR reduction of L-xylulose and diacetyl. Competitive inhibition of enzyme activity by the quinone was observed with respect to diacetyl (Ki = 190 μM) and L-xylulose (Ki = 940 μM). Abundant DCXR activity was identified in A549 lung epithelial cells when diacetyl was used as a substrate. Quinones inhibited reduction of this dicarbonyl, causing an accumulation of diacetyl in the cells and culture medium and a decrease in acetoin, the reduced product of diacetyl. The identification of DCXR as an enzyme activity mediating chemical redox cycling suggests that it may be important in generating cytotoxic reactive oxygen species in the lung. These activities, together with the inhibition of dicarbonyl/L-xylulose metabolism by redox-active chemicals, as well as consequent deficiencies in pentose metabolism, are likely to contribute to lung injury following exposure to dicarbonyls and quinones.
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- 2017
7. Neuroprotective effects of the SCR1–3 functional domain of CR1 on acute cerebral ischemia and reperfusion injury in rats
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Xiaoyan Wang, Xuan Zhang, Zhengqing Wang, Shaojun Yang, and Yanzhi Lu
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Male ,Neutrophils ,Blotting, Western ,Ischemia ,Inflammation ,Pharmacology ,Severity of Illness Index ,Neuroprotection ,Rats, Sprague-Dawley ,Random Allocation ,Complement Receptor Type 1 ,Consensus Sequence ,Complement C4b ,medicine ,Animals ,Protein Interaction Domains and Motifs ,Receptor ,Movement Disorders ,biology ,business.industry ,Brain ,Infarction, Middle Cerebral Artery ,General Medicine ,medicine.disease ,Immunohistochemistry ,Rats ,Receptors, Complement ,Complement system ,Neuroprotective Agents ,Neurology ,Reperfusion Injury ,Myeloperoxidase ,Anesthesia ,biology.protein ,Neurology (clinical) ,medicine.symptom ,business ,Reperfusion injury - Abstract
Complement receptor type 1 (CR1), one of the most potent inhibitors in complement activation, shows a protective effect on cerebral ischemia/reperfusion (CI/R) injury due to its ability to bind C3b and C4b and to inactivate C3/C5 convertases. So far, no study assessed the effect of the first three short consensus repeats (SCR1-3) with low molecular weight, one of the most active functional domains of CR1, binding C4b with a powerful decay-acceleration effect on classical and alternative C3/C5 convertases pathways. Therefore, we aim to assess this effect on CI/R injury in the present study.Seventy-five adult male Sprague-Dawley rats were randomly divided into three groups: sham operation group (n = 15), CI/R group (n = 30), and CI/R group treated with CR1-SCR1-3 protein (n = 30). After middle cerebral artery occlusion (MCAO) for 1 hour and reperfusion for 24 hours, neurological motor deficits, cerebral infarct size, and biochemical parameters including myeloperoxidase (MPO), malondialdehyde (MDA), and superoxide dismutase (SOD) were assessed. Meanwhile, tissues in cerebral cortex were collected and processed for western blotting, immunohistochemistry, and HE staining.CR1-SCR1-3 could improve neurological functions in brain with a 26.8% decrease in neurological motor deficit score and could lead to a 63.8% reduction in cerebral infarct size. Besides, pretreatment using CR1-SCR1-3 could prevent neutrophil infiltration and alleviate inflammation severity and subsequent tissue damage. Decreased C4b expression and action, as well as improved morphological changes, were also observed in cerebral tissues of CI/R+CR1-SCR1-3 rats.CR1-SCR1-3 protein could possess a neuroprotective effect on acute CI/R injury.
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- 2013
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8. EFFECTS OF P DEFICIENCY ON PROTECTIVE ENZYME ACTIVITY AND MEMBRANE LIPID PEROXIDATION IN DIFFERENT TOMATO GENOTYPES
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Weimin Zhu, Yanhui Wan, Zhijie Yang, Shaojun Yang, and Longying Zhu
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biology ,Phosphorus ,food and beverages ,chemistry.chemical_element ,Horticulture ,Enzyme assay ,Lipid peroxidation ,Superoxide dismutase ,chemistry.chemical_compound ,chemistry ,Catalase ,biology.protein ,Phosphorus deficiency ,Plant nutrition ,Peroxidase - Abstract
The protective enzyme activity and membrane lipid peroxidation in leaves at different P levels in nine tomato genotypes collected from the world were studied in nutrient solution culture. Phosphorus deficiency decreased leaf Chl contents. Compared with the control, there was a slight change of catalase activities in tomato seedlings under P deficiency, but superoxide dismutase activities, peroxidase activities and membrane-lipid peroxidation contents increased in phosphorus deficiency seedlings. There were differences in SOD activities, POD activities and MDA contents among tomato genotypes. The SOD activities under P deficiency stress in No. 4 and No. 54 increased more than that in No. 46, No. 2738 and No. 37 as compared with control seedlings. POD activities under P deficiency stress in No. 27, No. 37 and No. 46 increased more than that in No. 4, No. 25 and No. 2738. MDA contents under P deficiency stress in No. 2, No. 4 and No. 2738 increased more than that in No. 25, No. 27 and No. 37 as compared with control seedlings. These results indicated that the possible role of SOD activities, POD activities and MDA contents as anti-oxidant protector systems for tomato plants under phosphorus deficiency. Moreover, they suggest the possibility of using these enzyme activities as an additional screening criterion for detecting phosphorus efficiency in tomato genotypes.
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- 2010
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9. Inhibition of Sepiapterin Mediated Formation of Dihydrobiopterin and Chemical Redox Cycling by Sulfa Drugs
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Vladimir Mishin, Jason R. Richardson, Diane E. Heck, Jeffrey D. Laskin, Shaojun Yang, Debra L. Laskin, Yi-Hua Jan, and Ned D. Heindel
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chemistry.chemical_classification ,Sepiapterin ,biology ,Tetrahydrobiopterin ,Metabolism ,Biochemistry ,Cofactor ,Amino acid ,chemistry.chemical_compound ,chemistry ,Dihydrobiopterin ,Genetics ,biology.protein ,medicine ,One-electron reduction ,Sepiapterin reductase ,Molecular Biology ,Biotechnology ,medicine.drug - Abstract
Sepiapterin reductase (SPR) catalyzes the reduction of sepiapterin to dihydrobiopterin (BH2), a precursor for tetrahydrobiopterin (BH4), a cofactor critical for nitric oxide biosynthesis and alkylglycerol and aromatic amino acid metabolism. SPR also mediates chemical redox cycling, catalyzing one electron reduction of redox active chemicals including quinones; rapid reaction of these radicals with molecular oxygen generates reactive oxygen species (ROS). Using recombinant human SPR, sulfonamide and sulfonylurea based sulfa drugs were found to be potent non-competitive inibitors of both sepiapterin reduction and redox cycling. The most active inhibitors of sepiapterin reduction (IC50's = 31-180 nM) were sulfasalazine, sulfathiazole, sulfapyridine, sulfamethoxazole and chlorpropamide. Higher concentrations of the sulfa drugs (IC50's = 0.37-19.4 µM) were required to inhibit redox cycling. In PC12 cells, which generate catecholamine and monoamine neurotransmitters via BH4-dependent amino acid hydroxylases, su...
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- 2015
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10. Sulfa drugs inhibit sepiapterin reduction and chemical redox cycling by sepiapterin reductase
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Ned D. Heindel, Vladimir Mishin, Muhammad M. Hossain, Diane E. Heck, Jason R. Richardson, Yi-Hua Jan, Jeffrey D. Laskin, Debra L. Laskin, and Shaojun Yang
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Sepiapterin ,Toxicology ,PC12 Cells ,Cofactor ,Protein Structure, Secondary ,chemistry.chemical_compound ,Mice ,Sulfathiazole ,Menadione ,Dihydrobiopterin ,medicine ,Animals ,Humans ,Sepiapterin reductase ,Pharmacology ,chemistry.chemical_classification ,Sulfathiazoles ,biology ,Chemistry ,Metabolism ,Tetrahydrobiopterin ,Pterins ,Rats ,Sulfasalazine ,Alcohol Oxidoreductases ,Enzyme ,Biochemistry ,biology.protein ,Molecular Medicine ,Oxidation-Reduction ,medicine.drug - Abstract
Sepiapterin reductase (SPR) catalyzes the reduction of sepiapterin to dihydrobiopterin (BH2), the precursor for tetrahydrobiopterin (BH4), a cofactor critical for nitric oxide biosynthesis and alkylglycerol and aromatic amino acid metabolism. SPR also mediates chemical redox cycling, catalyzing one-electron reduction of redox-active chemicals, including quinones and bipyridinium herbicides (e.g., menadione, 9,10-phenanthrenequinone, and diquat); rapid reaction of the reduced radicals with molecular oxygen generates reactive oxygen species (ROS). Using recombinant human SPR, sulfonamide- and sulfonylurea-based sulfa drugs were found to be potent noncompetitive inhibitors of both sepiapterin reduction and redox cycling. The most potent inhibitors of sepiapterin reduction (IC50s = 31–180 nM) were sulfasalazine, sulfathiazole, sulfapyridine, sulfamethoxazole, and chlorpropamide. Higher concentrations of the sulfa drugs (IC50s = 0.37–19.4 μM) were required to inhibit redox cycling, presumably because of distinct mechanisms of sepiapterin reduction and redox cycling. In PC12 cells, which generate catecholamine and monoamine neurotransmitters via BH4-dependent amino acid hydroxylases, sulfa drugs inhibited both BH2/BH4 biosynthesis and redox cycling mediated by SPR. Inhibition of BH2/BH4 resulted in decreased production of dopamine and dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, and 5-hydroxytryptamine. Sulfathiazole (200 μM) markedly suppressed neurotransmitter production, an effect reversed by BH4. These data suggest that SPR and BH4-dependent enzymes, are “off-targets” of sulfa drugs, which may underlie their untoward effects. The ability of the sulfa drugs to inhibit redox cycling may ameliorate ROS-mediated toxicity generated by redox active drugs and chemicals, contributing to their anti-inflammatory activity.
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- 2015
11. Using DNA microarray to study human cytomegalovirus gene expression
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Anthony Galante, Fenyong Liu, Patricia Soteropoulos, Shaojun Yang, Weijia Wang, Saleena Ghanny, Walter Dunn, and Hua Zhu
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Human cytomegalovirus ,Microarray ,viruses ,Cytomegalovirus ,Gene Expression ,Biology ,medicine.disease_cause ,Herpesviridae ,Cell Line ,Virology ,Gene expression ,medicine ,Humans ,RNA, Messenger ,Gene ,Oligonucleotide Array Sequence Analysis ,Gene Expression Profiling ,Reproducibility of Results ,Fibroblasts ,medicine.disease ,Molecular biology ,Open reading frame ,RNA, Viral ,DNA microarray ,Functional genomics - Abstract
DNA microarray technology has become one of the most widely used tools for functional genomics and is playing an ever increasing role in the study of viral infections and host–pathogen interactions. This paper describes the development of an oligonucleotide microarray representing all the predicted open reading frames of the human cytomegalovirus (HCMV) and an established protocol for simultaneously measuring the expression of all HCMV genes. To evaluate the performance of the HCMV array, human foreskin fibroblasts were either mock infected or infected with the HCMV AD169 or Toledo strains. Hybridizations were performed to determine the level of detection of HCMV transcripts from both the AD169 and Toledo strains and to assess reproducibility within and between slides. Overall, approximately 95% of the predicted HCMV genes produced detectable levels of mRNA, with median signal to noise and signal to background ratios of 41 and 14, respectively. Scatter plots of samples within an array and between two arrays resulted in average linear regressions above 0.95 and 0.9, respectively, indicating that data from the arrays are highly reproducible. In addition, transcripts from genes found in the Toledo strain but not in AD169 were specifically detected.
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- 2006
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12. Postattachment Events Associated with Viral Entry Are Necessary for Induction of Interferon-Stimulated Genes by Human Cytomegalovirus
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Thomas R. Jones, James R. Netterwald, Ian P. McCrone, Shaojun Yang, William J. Britt, and Hua Zhu
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Human cytomegalovirus ,viruses ,Immunology ,Cytomegalovirus ,Biology ,medicine.disease_cause ,Membrane Fusion ,Microbiology ,Herpesviridae ,Virus ,Viral Envelope Proteins ,Viral entry ,Interferon ,Virology ,medicine ,Humans ,Cells, Cultured ,Regulation of gene expression ,Virion ,Proteins ,virus diseases ,Lipid bilayer fusion ,Fibroblasts ,medicine.disease ,Virus-Cell Interactions ,Gene Expression Regulation ,Insect Science ,biology.protein ,Interferons ,Antibody ,medicine.drug - Abstract
Utilizing a human cytomegalovirus-specific fusion inhibitor and an antiglycoprotein H antibody, we studied the role of virion fusion in interferon-stimulated gene (ISG) induction. Our results indicate that ISG induction does not occur when virion-mediated, post-high-affinity attachment events are inhibited by either reagent. Thus, virion-mediated postattachment events, such as fusion, are required for ISG induction.
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- 2004
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13. Salicylic acid alleviates cadmium-induced inhibition of growth and photosynthesis through upregulating antioxidant defense system in two melon cultivars (Cucumis melo L.)
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Shaojun Yang, Chen Youyuan, Shuang Xu, and Yongping Zhang
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Chlorophyll ,Antioxidant ,Light ,Proline ,Melon ,medicine.medical_treatment ,Plant Science ,Plant Roots ,Antioxidants ,Fluorescence ,Superoxide dismutase ,Lipid peroxidation ,chemistry.chemical_compound ,Cucumis melo ,Superoxides ,Malondialdehyde ,Botany ,medicine ,Biomass ,Photosynthesis ,Plant Proteins ,biology ,food and beverages ,Photosystem II Protein Complex ,Cell Biology ,General Medicine ,Up-Regulation ,Plant Leaves ,Horticulture ,chemistry ,Solubility ,Catalase ,biology.protein ,Gases ,Lipid Peroxidation ,Salicylic Acid ,Salicylic acid ,Plant Shoots ,Cadmium - Abstract
Cadmium (Cd) is a widespread toxic heavy metal that usually causes deleterious effects on plant growth and development. Salicylic acid (SA), a naturally existing phenolic compound, is involved in specific responses to various environmental stresses. To explore the role of SA in the tolerance of melon (Cucumis melo L.) to Cd stress, the influence of SA application on the growth and physiological processes was compared in the two melon cultivars Hamilv (Cd-tolerant) and Xiulv (Cd-sensitive) under Cd stress. Under 400-μM Cd treatment, Hamilv showed a higher biomass accumulation, more chlorophyll (Chl), greater photosynthesis, and less oxidative damage compared to Xiulv. Foliar spraying of 0.1 mM SA dramatically alleviated Cd-induced growth inhibition in the two melon genotypes. Simultaneously, SA pretreatment attenuated the decrease in Chl content, photosynthetic capacity, and PSII photochemistry efficiency in Cd-stressed plants. Furthermore, exogenous SA significantly reduced superoxide anion production and lipid peroxidation, followed by increase in the activities of antioxidant enzyme superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase, and content of soluble protein and free proline in both the genotypes under Cd stress. The effect of SA was more conspicuous in Xiulv than Hamilv, reflected in the biomass, photosynthetic pigments, stomatal conductance, water use efficiency, and antioxidant enzymes. These results suggest that exogenous spray of SA can alleviate the adverse effects of Cd on the growth and photosynthesis of both the melon cultivars, mostly through promoting antioxidant defense capacity. It also indicates that SA-included protection against Cd damage is to a greater extent more pronounced in Cd-sensitive genotype than Cd-tolerant genotype.
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- 2014
14. Rapid Detection of Hepatitis B Virus Variants Associated with Lamivudine and Adefovir Resistance by Multiplex Ligation-Dependent Probe Amplification Combined with Real-Time PCR
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Shaojun Yang, Kejun Zhang, Feng Wang, Ming Chen, Shaoli Deng, Wenbin Jiang, Fake Li, Shuangrong Jia, Ya Shang, and Kai Chang
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Microbiology (medical) ,Hepatitis B virus ,Organophosphonates ,Microbial Sensitivity Tests ,Biology ,medicine.disease_cause ,Real-Time Polymerase Chain Reaction ,Antiviral Agents ,Sensitivity and Specificity ,Time ,Hepatitis B, Chronic ,Virology ,Multiplex polymerase chain reaction ,Drug Resistance, Viral ,medicine ,Adefovir ,Humans ,Multiplex ,Multiplex ligation-dependent probe amplification ,Adenine ,Lamivudine ,Hepatitis B ,medicine.disease ,Molecular biology ,Real-time polymerase chain reaction ,Molecular Diagnostic Techniques ,Mutation ,Multiplex Polymerase Chain Reaction ,medicine.drug - Abstract
Drug-resistant mutations of hepatitis B virus (HBV) are the major obstacles to successful therapy for chronic hepatitis B infection. Although there are many methods for detecting the antiviral drug-resistant mutations of HBV, their applications are restricted because of their shortcomings, such as low sensitivity, the time required, and the high cost. For this study, a multiplex ligation-dependent probe real-time PCR (MLP-RT-PCR) method was developed to simultaneously detect lamivudine (LAM)- and adefovir (ADV)-resistant HBV mutants (those with the mutations rtM204V/I, rtA181V/T, and rtN236T). The new method combined the high-throughput nature of multiplex ligation-dependent probe amplification (MLPA) with the rapid and sensitive detection of real-time PCR. In this report, MLP-RT-PCR was evaluated by detecting drug-resistant mutants in 116 patients with chronic hepatitis B infection. By MLP-RT-PCR analysis, LAM-resistant mutations were detected in 41 patients (35.3%), ADV-resistant mutations were detected in 17 patients (14.7%), and LAM- and-ADV-resistant mutations were detected in 5 patients (4.3%). Based on the results of MLP-RT-PCR, the mutations rtM204V, rtM204I, rtA181T, rtA181V, and rtN236T were 95.7% (111/116 patients), 98.3% (114/116 patients), 99.1% (115/116 patients), 98.3% (114/116 patients), and 99.1% (115/116 patients) concordant, respectively, with those of direct sequencing. The MLP-RT-PCR assay was more sensitive than direct sequencing for detecting mutations with low frequencies. Four samples containing the low-frequency (
- Published
- 2014
15. Process conditions affecting proteolysis of recombinant proteins in Escherichia coli
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Sven-Olof Enfors and Shaojun Yang
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Chromatography ,medicine.diagnostic_test ,biology ,Proteolysis ,Binding protein ,Bioengineering ,General Medicine ,equipment and supplies ,medicine.disease_cause ,biology.organism_classification ,complex mixtures ,Applied Microbiology and Biotechnology ,Enterobacteriaceae ,law.invention ,Biochemistry ,law ,medicine ,Bioreactor ,Recombinant DNA ,biology.protein ,Protein A ,Escherichia coli ,Bacteria ,Biotechnology - Abstract
The effects of process conditions on proteolysis of three recombinant IgG-binding proteins ZT3, ZZT3 and protein A in E. coli were studied. SDS/PAGE shows that the relative amount of degradation intermediates of ZT3 in a shake flask cultivation is much higher than that in a bioreactor culture. The rate of proteolysis of ZZT3 and protein A was also higher in shake flask cultures than in bioreactor cultures. The proteolysis rate constant of ZZT3 was 12/h in a shake flask but only 2.1/h in a bioreactor. Corresponding values for protein A were 2.4/h and 1.0/h, respectively. High proteolysis rate constants correlated with lower product yields.
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- 1996
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16. Coupling generation of cytomegalovirus deletion mutants and amplification of viral BAC clones
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Shaojun Yang, Catherine E. Patterson, Weijia Wang, and Hua Zhu
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Human cytomegalovirus ,DNA, Bacterial ,Chromosomes, Artificial, Bacterial ,viruses ,Clone (cell biology) ,Drug Resistance ,Cytomegalovirus ,Replication Origin ,Biology ,medicine.disease_cause ,Origin of replication ,law.invention ,Open Reading Frames ,law ,Virology ,medicine ,Escherichia coli ,Humans ,Cloning, Molecular ,Gene ,Cells, Cultured ,Recombination, Genetic ,Mutation ,Circular bacterial chromosome ,medicine.disease ,Molecular biology ,Deletion Mutagenesis ,Recombinant DNA ,Transformation, Bacterial ,Gene Deletion - Abstract
Human cytomegalovirus (HCMV) genome manipulation has always been difficult. Recently, the introduction of full-length HCMV DNA into Escherichia coli as an artificial bacterial chromosome (BAC) clone has allowed reliable targeted mutagenesis. Here, we show the next generation of improvement in designing recombinant HCMV, which will also be applicable to other viral BAC clones. An inducible origin of replication linked with an antibiotic resistance marker was used as a cassette for targeted replacement of sequences within a HCMV BAC clone, TowneBAC. The origin of replication allowed for the induction of increased amounts BAC DNA that improved recovery, ease of use and transfections for mutant viruses. By specific deletion of UL147 and the recombinant GFP gene, we have shown that targeted deletion of a gene and selection for a recombinant genome are coupled with the ability to amplify the BAC clone DNA. These HCMV BAC clones were amplified approximately 10-fold. In the case of the removal of GFP from the clone TowneBAC shown in this study, the resulting BAC DNA preparation following amplification was used for successful primary cell transfection. Both parental and deletion BAC clone transfections gave similar levels of recombinant HCMV, and the GFP deletion virus replicated the same as the TowneBAC in a multi-step growth curve analysis.
- Published
- 2004
17. Impact of plasmid presence and induction on cellular responses in fed batch cultures of Escherichia coli
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Lena Andersson, Peter Neubauer, Sven-Olof Enfors, and Shaojun Yang
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Cell division ,Stringent response ,Population ,lac operon ,Gene Expression ,Bioengineering ,Guanosine Tetraphosphate ,Biology ,medicine.disease_cause ,Applied Microbiology and Biotechnology ,Microbiology ,Plasmid ,medicine ,Escherichia coli ,education ,education.field_of_study ,General Medicine ,biology.organism_classification ,Enterobacteriaceae ,Recombinant Proteins ,Culture Media ,Kinetics ,Biochemistry ,Bacteria ,Cell Division ,Biotechnology ,Plasmids - Abstract
Fed batch cultivations of plasmid-free and recombinant Escherichia coli were employed in order to determine cellular responses and effects of plasmid presence and induction on the host cell physiology. While plasmid presence was shown to have minor influence on overall biomass yield, induction with 0.1 mM IPTG led to a marked reduction. The number of dividing cells, measured as colony forming ability, was influenced by plasmid presence and to a larger extent by induction. The latter caused a decline in the number of dividing cells to less than 10% of the population within 10 h. However, this cell segregation did not affect the specific rate of product formation, which was approximately constant throughout the cultivations. Analysis of the in vivo degradation rate of the product indicated that it was proteolytically stable. The cellular content of the stringent response signal substance, ppGpp, peaked immediately after transition from batch to fed batch mode to stabilise at a higher value than in the batch phase. When the specific growth rate declined below 0.06 h-1 an additional rise in ppGpp concentration was observed.
- Published
- 1996
18. The Escherichia Coli. Chaperone DnaK: Properties and Potentials
- Author
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Kristina Gustavsson, Andres Veide, Shaojun Yang, and Sven-Olof Enfors
- Subjects
medicine.diagnostic_test ,biology ,Proteolysis ,genetic processes ,Ion chromatography ,medicine.disease_cause ,Plasmid ,Affinity chromatography ,Biochemistry ,IgG binding ,Chaperone (protein) ,biological sciences ,medicine ,biology.protein ,bacteria ,Protein A ,Escherichia coli - Abstract
A method to produce native DnaK from E. coli was developed based on induction of DnaK production by heat shock in E. coli cells furnished with a plasmid coding for a truncated staphylococcal protein A. DnaK forms a complex with this protein A molecule and the complex could be purified by IgG affinity chromatography. The two molecules of the complex were then separated by ion exchange chromatography. The DnaK did not bind to the ZZTO molecule, which is an IgG binding derivative of the B domain of protein A. Insertion of tryptophan residues into ZZTO induced DnaK complex formation as well as proteolysis of the product. The technical perspectives of utilizing the selective binding of chaperones like DnaK to proteins with nonper-missible structure is discussed.
- Published
- 1996
- Full Text
- View/download PDF
19. The influence of energy sources on the proteolysis of a recombinant staphylococcal protein A in Escherichia coli
- Author
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Shaojun Yang and Sven-Olof Enfors
- Subjects
medicine.diagnostic_test ,Proteolysis ,Temperature ,Biology ,medicine.disease_cause ,Biochemistry ,Recombinant Proteins ,law.invention ,Culture Media ,chemistry.chemical_compound ,Kinetics ,L-Glucose ,chemistry ,law ,medicine ,Recombinant DNA ,biology.protein ,Escherichia coli ,Sodium azide ,Fermentation ,Energy source ,Protein A ,Staphylococcal Protein A - Abstract
The kinetics of proteolysis of a recombinant staphylococcal protein A in Escherichia coli were studied by a Western-blotting-based method. The proteolysis constants obtained from this method are very close to those obtained from the traditional radioactive pulse-chase technique. Protein A was selectively degraded to a great extent, while host proteins were quite stable after heat induction of protein A expression. The proteolysis of protein A was much faster in the presence of energy sources compared to when cells were starved of energy. The degradation rate constants are 2.8 h-1 in the presence of 10 g/l glucose and about 0.4 h-1 in the absence of any external carbon source. The supplementation of glucose to the medium at 0-100 mg/l caused a gradual increase of proteolysis of protein A, but the proteolysis was saturated when the concentration of glucose exceeded 200 mg/l at a cell concentration of about 0.36 g/l. The respiration inhibitor sodium azide completely inhibited the degradation of protein A in glucose-free salt medium but had almost no effect in the presence of glucose. Therefore, the proteolysis process is energy dependent but the energy supply rate obtained by fermentation of glucose is enough to meet this requirement. The proteolysis rate increased with the temperature in the interval 5-45 degrees C but was then reduced due to damage of the proteolysis system by high temperature. At 60 degrees C, the proteolysis ceased completely within 30 min.
- Published
- 1995
20. Effects of amino acid insertions on the proteolysis of a staphylococcal protein A derivative in Escherichia coli
- Author
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Tomas Bergman, Andres Veide, Sven-Olof Enfors, and Shaojun Yang
- Subjects
Proteolysis ,Molecular Sequence Data ,Biology ,medicine.disease_cause ,Biochemistry ,Structure-Activity Relationship ,Endopeptidases ,medicine ,Protein biosynthesis ,Escherichia coli ,HSP70 Heat-Shock Proteins ,Amino Acid Sequence ,Staphylococcal Protein A ,chemistry.chemical_classification ,medicine.diagnostic_test ,Tetrapeptide ,Escherichia coli Proteins ,Tryptophan ,Chaperonin 60 ,Hydrogen-Ion Concentration ,Molecular biology ,GroEL ,Peptide Fragments ,Recombinant Proteins ,Amino acid ,Kinetics ,chemistry ,Immunoglobulin G ,Electrophoresis, Polyacrylamide Gel ,Isoleucine - Abstract
In vivo proteolysis of protein ZZT0, derived from the B domain of staphylococcal protein A, was investigated in Escherichia coli before and after insertion of 1 – 3 multiples of the tetrapeptide Ala-Trp-Trp-Pro close to the C-terminus of ZZT0. Before insertion, ZZT0 was proteolytically stable as judged from the purity of IgG binding proteins up to 1 h after inhibition of protein synthesis with chloramphenicol. Insertion of 1 – 3 units of Ala-Trp-Trp-Pro into ZZT0 increased progressively the sensitivity to proteolysis and induced DnaK and GroEL binding to the protein. The time for 50%in vivo hydrolysis of the full length protein derivative that was most susceptible to proteolysis, i.e. with three tetrapeptide units, was about 40 min when cultivated in a bioreactor and about 4 min in a shaken flask culture. Molecular masses and N-terminal sequences of the main degradation products indicated that protein ZZT0 is cleaved at identical sites irrespective of the number of inserted tetrapeptide units and that the cleavage sites are located far from the insertion point. Insertion of another hydrophobic amino acid, isoleucine, as the tetrapeptide Ala-Ile-Ile-Pro, only induced a slight proteolysis of the ZZT0 molecule under similar conditions. This indicates that the insertion of tryptophan residues, rather than of a general hydrophobic segment, plays an essential role in the induced proteolysis of the ZZT0 protein.
- Published
- 1994
21. Fabrication of an electrochemical platform based on the self-assembly of graphene oxide–multiwall carbon nanotube nanocomposite and horseradish peroxidase: direct electrochemistry and electrocatalysis
- Author
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Jing Zhang, Ling Zhang, Qian Zhang, Shaojun Yang, Hua Zhou, Jinghong Li, Pingli Kang, Xi-Ming Song, and Jingwei Xu
- Subjects
medicine.medical_specialty ,Materials science ,Inorganic chemistry ,Bioengineering ,Biosensing Techniques ,Carbon nanotube ,Glassy carbon ,Electrocatalyst ,Horseradish peroxidase ,Catalysis ,law.invention ,Nanomaterials ,law ,medicine ,General Materials Science ,Electrical and Electronic Engineering ,Electrodes ,Horseradish Peroxidase ,Nanocomposite ,Sodium Nitrite ,biology ,Nanotubes, Carbon ,Graphene ,Mechanical Engineering ,Reproducibility of Results ,Oxides ,Electrochemical Techniques ,Hydrogen Peroxide ,General Chemistry ,Enzymes, Immobilized ,Mechanics of Materials ,Bioelectrochemistry ,biology.protein ,Graphite ,Oxidation-Reduction - Abstract
A novel hybrid nanomaterial (GO-MWNTs) was explored based on the self-assembly of multiwall carbon nanotubes (MWNTs) and graphene oxide (GO). Compared with pristine MWNTs, such a nanocomposite could be well dispersed in aqueous solution and exhibit a negative charge. Driven by the electrostatic interaction, positively charged horseradish peroxidase (HRP) could then be immobilized onto GO-MWNTs at the surface of a glassy carbon (GC) electrode to form a HRP/GO-MWNT/GC electrode under mild conditions. TEM was used to characterize the morphology of the GO-MWNT nanocomposite. UV-vis and FTIR spectra suggested that HRP was immobilized onto the hybrid matrix without denaturation. Furthermore, the immobilized HRP showed enhanced direct electron transfer for the HRP-Fe(III)/Fe(II) redox center. Based on the direct electron transfer of the immobilized HRP, the HRP/GO-MWNT/GC electrode exhibited excellent electrocatalytic behavior to the reduction of H(2)O(2) and NaNO(2), respectively. Therefore, GO-MWNTs could provide a novel and efficient platform for the immobilization and biosensing of redox enzymes, and thus may find wide potential applications in the fabrication of biosensors, biomedical devices, and bioelectronics.
- Published
- 2011
- Full Text
- View/download PDF
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