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Objective@#To optimize the sample pretreatment and establish an ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap-MS) assay based on the parallel reaction monitoring (PRM) mode for determination of antibiotic residues in chicken meat.@*Methods@#Blank matrix-spiked chicken meat samples were extracted with 95% acetonitrile aqueous solution containing Na2EDTA and formic acid. The extraction solutions were cleaned up using different combinations of C18, PSA and GCB fillers, and the combinations with a higher antibiotic recovery rate was screened. The residues of 32 antibiotics were determined using UPLC-Q-Orbitrap-MS based on the PRM mode.@*Results@#If the extraction solution was cleaned up using the C18 filler, the largest number of antibiotics with a spiked recovery rate of >80% was seen, with matrix effects of 82.2% to 112.6%. The detection limits of 32 antibiotics were 0.8 to 5.8 μg/kg, with linear correlation coefficients of >0.99, spiked recovery rates of 71.3% to 111.5% and relative standard deviations of 3.2% to 14.2%.@*Conclusion@#The UPLC-Q-Orbitrap-MS assay is suitable for determination and quantitative analysis of multiple antibiotics in chicken meat. Key words： high-resolution mass spectrometry orbitrap antibiotic residue parallel reaction monitoring
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Objective@#To optimize the enzymatic digestion conditions of trypsin, so as to improve the testing capacity of mass spectrometry for shrimp allergens.@*Methods@#The enzymatic digestion test was carried out by response surface methodology for optimizing pH, temperature and time. After enzymatic hydrolysis, the peptides were separated by chromatography and determined by high-resolution mass spectrometry with Q-orbitrap. The allergen protein was identified and quantified by UniProt database and MaxQuant software.@*Results@#Two allergen proteins, tropomyosin and arginine kinase, were isolated from shrimp, and their intensities ranged from 100.2×106 to 436.5×106. Response surface analysis showed that when the digestion time was 4.29 hours, the temperature was 44.15 ℃ and pH value was 6.55, the maximal intensity of the allergen proteins was 457.48×106. The experiment was validated with the digestion time of 4.2 h, pH value of 6.5, and temperature of 44 ℃, then resulted in the average intensity of 448.1×106. The deviation from the predicted value was 2.1%.@*Conclusions@#The conditions of enzymatic digestion can be optimized by response surface methodology. The enzyme may have the best performance with the pH value of 6.5, temperature of 44 ℃ and digestion time of 4.2 hours.
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Objective@#To establish the ultra-high performance liquid chromatography coupled with quadrupole orbitrap mass spectrometry ( UPLC-Q-Orbitrap-MS ) for the analysis of allergen protein in Macrobrachium. @*Methods@#Based on the strategy of bottom-up protein analysis, the proteins in Macrobrachium samples were extracted by Tris-HCl, digested by trypsin at 40 ℃ for 6 hours, separated by chromatography, and analyzed by Q-Orbitrap-MS spectrometry ( Full MS/dd-MS2, TopN=10 ) . Allergen proteins were identified with UniProt protein database and Proteome Discoverer software. @*Results@# Four kinds of allergen proteins were obtained, which were tropomyosin, arginine kinase, sarcoplasmic calcium binding protein and hemocyanin. The coverage rates of peptides in proteins were 53%, 36%, 12% and 12%, respectively. Post translation modifications were methylation of aspartic acid (D), deacylylation of aspartic acid ( N ) , glutamyl ammonia ( Q ) and oxidation of methionine ( M ) .@*Conclusions@#The UPLC-Q-Orbitrap-MS can identified abundant peptide and fragment information with high sensitivity and resolution, which provides a technical support for the analysis of shrimp allergens.
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@# Objective: To assess the association between interleukin-17 (IL-17) gene rs763780 polymorphism and susceptibility of gastric cancer using Meta-analysis. Methods: A comprehensive search was performed on PubMed, EMBASE, the Cochrane Library, Web of Science, Wanfang Database, Chinese Biomedical Literature Database, Chinese Science and Technology Academic Journal and Chinese Journal Full-text Database from their inception to December 2017 to identify relevant case-control studies on association between interleukin-17 (IL-17) gene rs763780 polymorphism and susceptibility of gastric cancer. Meta-analysis was performed using STATA 12.0 software. Results: A total of 10 case-control studies were included in this Meta-analysis, involving 3 892 gastric cancer cases and 4 627 controls. The results showed that there was association between IL-17 rs763780 polymorphism and gastric cancer risk in allele genetic model (C vs T: OR=1.90, 95% CI=1.73-2.08), additive model (CC vs TT: OR=1.76, 95% CI=1.45-2.14), codominant model (CC vs CT: OR =1.26, 95% CI=1.13-1.42), dominant model (CC vs CT+TT: OR=1.93, 95% CI=1.65-2.26) and recessive model (TT vs CT+CC: OR=1.67, 95% CI=1.38-2.03). Conclusion: IL-17 rs763780 polymorphism increases the risk of gastric cancer.