ABSTRACT
Research on molecular mechanisms of carcinogenesis plays an important role in diagnosing and treating gastric cancer. Metabolic profiling may offer the opportunity to understand the molecular mechanism of carcinogenesis and help to non-invasively identify the potential biomarkers for the early diagnosis of human gastric cancer. The aims of this study were to explore the underlying metabolic mechanisms of gastric cancer and to identify biomarkers associated with morbidity. Gas chromatography/mass spectrometry (GC/MS) was used to analyze the serum metabolites of 30 Chinese gastric cancer patients and 30 healthy controls. Diagnostic models for gastric cancer were constructed using orthogonal partial least squares discriminant analysis (OPLS-DA). Acquired metabolomic data were analyzed by the nonparametric Wilcoxon test to find serum metabolic biomarkers for gastric cancer. The OPLS-DA model showed adequate discrimination between cancer and non-cancer cohorts while the model failed to discriminate different pathological stages (I-IV) of gastric cancer patients. A total of 44 endogenous metabolites such as amino acids, organic acids, carbohydrates, fatty acids, and steroids were detected, of which 18 differential metabolites were identified with significant differences. A total of 13 variables were obtained for their greatest contribution in the discriminating OPLS-DA model [variable importance in the projection (VIP) value >1.0], among which 11 metabolites were identified using both VIP values (VIP >1) and the Wilcoxon test. These metabolites potentially revealed perturbations of glycolysis and of amino acid, fatty acid, cholesterol, and nucleotide metabolism of gastric cancer patients. These results suggest that gastric cancer serum metabolic profiling has great potential in detecting this disease and helping to understand its metabolic mechanisms.
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Middle Aged , Metabolome , Stomach Neoplasms/blood , Biomarkers, Tumor/blood , Adenocarcinoma , Case-Control Studies , Gas Chromatography-Mass Spectrometry , Neoplasm Staging , Stomach Neoplasms/diagnosis , Stomach Neoplasms/pathologyABSTRACT
<p><b>BACKGROUND</b>Gastric cancer (GC) is one of the most common types of cancer in the world. A change in the metabolism of lipids in tumor cells could lead to the pathogenesis of cancer. In this study, we investigated fatty acid and fatty acid amide metabolic perturbations associated with GC morbidity.</p><p><b>METHODS</b>Gas chromatography/mass spectrometry (GC/MS) was utilized to analyze fatty acids (FAs) and fatty acid amides (FAAs) of GC tissues and matched normal mucosae from 30 GC patients. Acquired lipid data was analyzed using non parametric Wilcoxon rank sum test to find the differential biomarkers for GC and diagnostic models for GC were established by using orthogonal partial least squares discriminant analysis (OPLS-DA).</p><p><b>RESULTS</b>A total of 13 FAs and 4 FAAs were detected using GC/MS and 5 differential FAs as well as oleamide were identified with significant difference (P<0.05). The OPLS-DA model generated from lipid profile showed adequate discrimination of GC tissues from normal mucosae while the OPLS-DA model failed to separate GC specimens of different TNM stages. A total of 8 variables were obtained for their most contribution in the discriminating model (Variable importance in the projection (VIP) value>1.0), five of which were detected with significant difference (P<0.05).</p><p><b>CONCLUSIONS</b>FA and FAA metabolic profiles have great potential in detecting GC and helping understand perturbations of lipid metabolism associated with GC morbidity.</p>
Subject(s)
Female , Humans , Male , Amides , Metabolism , Fatty Acids , Metabolism , Gas Chromatography-Mass Spectrometry , In Vitro Techniques , Metabolic Diseases , Stomach Neoplasms , Metabolism , PathologyABSTRACT
A novel biosensor for aflatoxin B1 detecting has been reported. The biosensor electrode for AFB1 detecting was assembled by immobilized aflatoxin-oxidoreductase using open-ended multi-walled carbon nanotubes as matrix. Its linear range was between 0.16μM and 3.2μM. And if the specific anti-aflatoxin B1 antibody and aflatoxin oxidoreductase were both immobilized on the electrode with Multi-Walled carbon nanotubes, the detection limit of the modified electrode could be 16 nM with a 10 times improved sensitivity. The aflatoxin enzyme biosensor assembled this way strode one step forward its practical application.
ABSTRACT
A novel biosensor for aflatoxin B1 detecting has been reported. The biosensor electrode for AFB1 detecting was assembled by immobilized aflatoxin-oxidoreductase using open-ended multi-walled carbon nanotubes as matrix. Its linear range was between 0.16μM and 3.2μM. And if the specific anti-aflatoxin B1 antibody and aflatoxin oxidoreductase were both immobilized on the electrode with Multi-Walled carbon nanotubes, the detection limit of the modified electrode could be 16 nM with a 10 times improved sensitivity. The aflatoxin enzyme biosensor assembled this way strode one step forward its practical application.
ABSTRACT
Armillariella tabescens EJLY2098 was induced to produce ?-mannanase with konjac fine flour (Amorphopallus rivieri) as single carbon source. This induced enzyme was then purified using DEAE ion exchange chromatography and named atMAN47. Zymologic analysis showed that the molecular weight of this ?-mannanase was approximately 47 kD. The enzyme was stable when pH ranged from 5.0 to 6.5 and could be activated by Na+ and Ba2+. With an optimal temperature of 50?C. Action mode analysis of TLC revealed that the enzyme belonged to the endo-?-mannanase family. Being a meta-acid endo-?-mannanase, it was suitable to be applied to feed industry with a promising future as an enzyme preparation.
ABSTRACT
A novel biosensor for aflatoxin B1 detecting has been reported. The biosensor electrode for AFB1 detecting was assembled by immobilized aflatoxin-oxidoreductase using open-ended multi-walled carbon nanotubes as matrix. Its linear range was between 0.16?M and 3.2?M. And if the specific anti-aflatoxin B1 antibody and aflatoxin oxidoreductase were both immobilized on the electrode with Multi-Walled carbon nanotubes, the detection limit of the modified electrode could be 16 nM with a 10 times improved sensitivity. The aflatoxin enzyme biosensor assembled this way strode one step forward its practical application.
ABSTRACT
Armillariella tabescens EJLY2098 was capable of secreting p-mannanase by konjac inducement. A 34 orthogonal design was applied to determine the optimum medium of inducing mannanase by Armillariella tabescens EJLY2098. The results suggested that Armillariella tabescens EJLY2098 secreted the high-activity enzyme in the optimum medium, which was composed of 2% konjac, 1% peptone, 25% potato juice,0.3% KH2PO4,15% MgSO4?7H2O, 0.01% VitB1. Purified by DEAE-anion exchange chromatography, two eluting peaks (P1 and P2) with the p-mannanase activity were obtained, and one of them (named?-mannanase P2) was a single band by the SDS-PAGE, and the molecular weight of?-mannanase P2 was 78. 9kDa. The isoelectric point of?-mannanase P2 was estimated to be 4.0-4. 1. The optimum activity for the enzyme was found at 60℃and pH4. 0 - 6. 0, and the enzyme was stable between pH4. 5 - 6. 0. The activity of?-mannanase P2 were enhanced by Na+ and Ba2+ . This?-mannanase can be used in feed industy. a new fungi secreting?-mannanase was obtained, providing an important base for cloning mannanase gene and constructing recombin microbe expressing?-mannanase .
ABSTRACT
SMART-RACE was performed after isolating the total RNA of Armillariella tabescens to amplify the full-length cDNA of arabinosidase (GenBank Accession No. AJ620046). Bioinformatics analysis was used to analyze the code frame of arabinosidase, to predict its structure and function. Recombinant plasmid pPIC9-AF was constructed and then electroporated into methylotrophic yeast Pichia pastoris GS115. The secreted 6 ? His fusion protein was purified to analyze its enzymology property. This arabinosidase had high activity at 30-35℃ under acid condition, and was stable within wide range of pH and temperature. It maintained about 80% activity at the range of pH4. 0-8.0 and 20-40℃,wider than many other cloned arabinosidase. So it was worthy to go step further to study this enzyme, and recombinant expression provided a chance of highly expressing arabinosidase.
ABSTRACT
The expression cDNA library of A. tabescens was constructed by SMART technique, which useλTriplEx2 as a vector. The titer and the percentage of the constructed library were about 1.0 × 106pfu/mland 98.3% respectively, and the titer and the capacity of the amplified library were about 3.1 × 108pfu/mland 4.2 × 1010. The library was used to provide expressed sequence tags (ESTs). 147 Expressed SequenceTaqs (ESTs) were gained from 176 clones, which were selected randomly and sequenced at the 5'end. Thesequences were submitted to the EMBL database. Blasting the sequences in the GenBank, 43 of them werefound that they have significant similarity with data in GenBank. EST AJ620046 was has significantsimilarity with the arabinosidase of Bacteroides thetaiotaomicron. Using SMART-RACE a full-length cDNA ofAJ620046 was successfully obtained. In order to initially characterize the biochemical properties ofAJ620046, the ORF of AJ620046 named AF was cloned and expressed in Pichia Pastoris yeast.Recombinant pHIL-S1-AF constructed by inserting AF into pHIL-S1 was transformed into Pichia PastorisGS115. Preliminary experiments indicated that AJ620046 was expressed as a 32 kDa protein in recombinantyeast.
ABSTRACT
The expression cDNA library of A. tabescens was constructed by SMART technique, which useλTriplEx2 as a vector. The titer and the percentage of the constructed library were about 1.0 × 106pfu/mland 98.3% respectively, and the titer and the capacity of the amplified library were about 3.1 × 108pfu/mland 4.2 × 1010. The library was used to provide expressed sequence tags (ESTs). 147 Expressed SequenceTaqs (ESTs) were gained from 176 clones, which were selected randomly and sequenced at the 5'end. Thesequences were submitted to the EMBL database. Blasting the sequences in the GenBank, 43 of them werefound that they have significant similarity with data in GenBank. EST AJ620046 was has significantsimilarity with the arabinosidase of Bacteroides thetaiotaomicron. Using SMART-RACE a full-length cDNA ofAJ620046 was successfully obtained. In order to initially characterize the biochemical properties ofAJ620046, the ORF of AJ620046 named AF was cloned and expressed in Pichia Pastoris yeast.Recombinant pHIL-S1-AF constructed by inserting AF into pHIL-S1 was transformed into Pichia PastorisGS115. Preliminary experiments indicated that AJ620046 was expressed as a 32 kDa protein in recombinantyeast.
ABSTRACT
Sterigmatocystin (ST), the secondary metabolite of many kinds of filamentous fungi, is a potent carcinogen structurally related to the aflatoxins (AFT). With similar chemical structure, sterigmatocystion behaves much the homogeneous properties to aflatoxins, both of these mycotoxins exhibit similar biological properties due to their bisfuranoid structure. Since the common, and even heavier pollution, found in foods and feeds-stuff, sterigmatocystion is more harmful than aflatoxins. The reported detection methods of sterigmatocystion included the Thin-layer Chromatography, the High-Performance-Liquid Chromatography, the Enzyme-Linked Immunosorbant Assay and the PCR detection to the toxic gene, however studies about both easy and inexpensive electro-chemical methods have not been found. Our previous studies had discovered that Sterigmatocystin (ST) exist similar sensitivity towards aflatoxin-detoxifizyme (ADTZ), which we had isolated from a fungus, as aflatoxin does. In this work, the preliminary study on electrochemical analysis and determination of ST with triplet electrode enzyme-biosensor system (Ag/AgCl as the reference electrode, Pt and Au as the pair and work electrode, respectively) was carried out. Multiwall-carbon-nanotube (MWNT) had been used to increase the electron transportation on electrode. In the research, the Au electrode was modified by MWNT-immobilized ADTZ, and then the voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. Autoprobe CP Research Atomic Force Microscope and TECNAI 10 Transmission Electron Microscope, had been used to detect the MWNT as well as the surface of MWNT-modified ADTZ. The voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. The results show that the red-ox peak potential of ST is at the point of -600 mV, the linear detection range is from 8.32 x 10(-5) to 66.56 x 10(-5) mg/mL, the detection limit is at 8.32 x 10(-5) mg/mL, and the response time is 10 seconds. This study provided a good basic work for further research.
Subject(s)
Biosensing Techniques , Methods , Electrochemistry , Microscopy, Atomic Force , Microscopy, Electron, Transmission , Nanotubes, Carbon , Chemistry , SterigmatocystinABSTRACT
Aflatoxins, found in contaminated food, are potent hepatocarcinogen. The aflatoxin-detoxiczyme (ADTZ) isolated from the edible fungus Armillariella sp., detoxifies aflatoxin B1 (AFB1). This paper reports on the characterization of immobilized ADTZ using a hydrophobic adsorption method. The ADTZ was isolated from cryo-homogenated fungus, previously cultivated at 24 - 28 degrees C for 20 - 30 days, using n-alkyl amino-agar beads. Various adsorption conditions of the enzyme to n-alkyl or n-octyl amino-agar beads were carried out. The effects of enzyme immobilization on different alkyl amino-agar beads, at different pH values (5.5 - 7.5), at different temperature (20 - 40 degrees C) and at different salt concentrations were investigated. The enzyme activity was measured at OD360 by reacting 133.3 ng/mL of AFB1 at 30 degrees C for 30 min with the immobilized ADTZ. The Km value of the immobilized enzyme, determined using Schematic Linewearver-Burk plot, is 3.308 x 10(-3) mol/L, lower than that of free enzyme, which is 2.16 x 10(-6) mol/L. This indicated the affinity of the detoxiczyme to AFB1 decreased after immobilization. The immobilized enzyme activity in oil-phase (n-hexane) was also studied with different concentration of water. After the treatment of the immobilized ADTZ, the toxin no longer causes liver toxicity in the rat toxicity test, no longer causes mutagenicity in Ames test and is no longer toxic in the chicken embryo test. Results also indicated that the pH stability, the thermostability and the freezing stability of ADTZ were improved after the immobilization.