Xin Li

Nanchang University, Nan-ch’ang-shih, Jiangxi Sheng, China

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Publications (14)33.32 Total impact

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    ABSTRACT: Backgroundβ-lactoglobulin is recognized as one of major allergens in milk and its epitopes include linear and conformational epitopes contributed to milk allergy. RESULTS: In our work, two types of epitopes have been identified. Linear epitopes identified by using SPOTTM peptide arrays approach and three common peptide sequences AA77-82 (KIPAVF), AA126-131 (PEVDNE) and AA142-147 (ALPMHI) were obtained by reacting with specific sera from two rabbits. At the same time, mimotopes were screened by the panning of phage display peptide library and the corresponding conformational epitopes were calculated by web tool of Peptiope server with Mapitope algorithm. Three conformational epitopes against two specific sera were identified, in which there were 15 common residues as well and located in the different position and appeared mainly as α-helix.Conclusion Common residues on the linear and conformational epitopes were identified in the first time, respectively, which could be regarded as informative epitopes for detection of allergen in dairy products.
    Journal of the Science of Food and Agriculture 12/2014; DOI:10.1002/jsfa.7033 · 1.88 Impact Factor
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    ABSTRACT: Peanut, as one of major food allergens, became an increasingly common life-threatening disorder. Although peanut allergens had been extensively identified, Ara h 1 is still too expensive to be applied in food safety or clinical utility. In this study, the purification, expression and immunological analyses of Ara h 1 were investigated.
    Preparative Biochemistry &amp Biotechnology 07/2014; DOI:10.1080/10826068.2014.940972 · 0.70 Impact Factor
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    ABSTRACT: In this work, a new method termed competitive fluorescence-linked immunosorbent assay (FLISA) was developed for specifically quantification of bovine α-lactalbumin (α-La) in dairy products. The monoclonal antibodies (mAbs) against α-La were produced through hybridoma technology, and the mAbs were covalently conjugated with the CdSe/ZnS quantum dots (QDs) using the crossing-linking reagents. Moreover, a competitive FLISA based on QD-mAb conjugates was established to detect α-La in dairy products. It was shown that there was a good linear relationship between inhibition efficiency, and logarithm of α-La concentration after the detection parameters were optimised in which the concentration of α-La varied from 0.1 to 1000 ng/mL. The value of IC50 was 0.03 μg/mL, and the FLISA method exhibited high sensitivity with the LOD at 0.1 ng/mL. The developed FLISA has been successfully applied to determine α-La in commercial dairy products, providing more sensitive analysis compared with the ELISA method.
    Food Chemistry 05/2014; 150:73–79. DOI:10.1016/j.foodchem.2013.10.137 · 3.26 Impact Factor
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    ABSTRACT: Until recently, celiac disease was considered to be rare in China. We aimed to estimate its true status. By searching the MEDLINE database and four Chinese full-text databases (CNKI, CBM, VIP and WANFANG) (up to August 2012), as well as two HLA allele frequency net databases and the Chinese Statistics Yearbook databases, we systematically reviewed the literature on definite and suspected cases of celiac disease, the predisposing HLA allele frequencies, and on gluten exposure in China. Meta-analysis was performed by analyzing DQ2, DQ8 and DQB1*0201 gene frequencies and heterogeneity in populations from different geographic regions and ethnicities in China. At present, the number of reported celiac disease cases is extremely low in China. The frequencies of the HLA-DQ2.5 and HLA-DQ8 haplotypes were 3.4% (95% confidence interval 1.3-5.5%) and 2.1% (0.1-4.1%), respectively. HLA-DQ2 and HLA-DQ8 antigen frequencies were 18.4% (15.0-21.7%) and 8.0% (4.5-11.4%), respectively. The frequency of the DQB1*0201 allele was 10.5% (9.3-11.6%) and it was more common in the northern Chinese than in the southern Chinese populations. The chance of being exposed to gluten is rapidly increasing all over China nowadays. The data on HLA haplotyping, in conjunction with increasing wheat consumption, strongly suggests that the occurrence of celiac disease is more common in China than currently reported. Coordinated measures by the Chinese government, medical and agricultural research institutions, and food industries, would be justified to create more awareness about celiac disease and to prevent it becoming a medical and societal burden.
    PLoS ONE 12/2013; 8(12):e81151. DOI:10.1371/journal.pone.0081151 · 3.53 Impact Factor
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    ABSTRACT: Ovotransferrin is one of the major allergens in egg white. To define the properties of ovotransferrin, a simple protocol for ovotransferrin purification was developed and a broad physicochemical and immunological assay were used for the characterization. The prepared ovotransferrin revealed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis, and had an estimated purity of more than 97%. The identity of the prepared protein identified by mass spectrometry analysis demonstrated that it was iron-free ovotransferrin with a molecular weight of 77,726 Da and pI value of 6.85, respectively, and its nature folded structure was kept well as defined by circular dichroism spectroscopy. Western blotting and enzyme-linked immunosorbent assays showed strong immune reactions between the prepared ovotransferrin and rabbit polyclonal antibody against ovotransferrin/egg-allergic patients' sera, suggesting that the prepared ovotransferrin bound to IgG and IgE strongly. In addition, 24 of the potential linear IgE binding epitopes on the prepared ovotransferrin were predicted using a web-based allergen database for food safety. The preparation method of ovotransferrin in the present work might provide scientific support to the authenticity of ovotransferrin for developing certified reference materials.
    International Journal of Food Properties 10/2013; 17(2):293-308. DOI:10.1080/10942912.2011.631249 · 0.91 Impact Factor
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    ABSTRACT: Peanut allergen Ara h 6 was isolated and irradiated at 1, 3, 5, or 10kGy, and a whole peanut protein extract (WPPE) was also treated by irradiation. Alteration in structure of Ara h 6 was characterised by circular dichroism (CD) spectroscopy, ultraviolet (UV) absorption spectroscopy, fluorescence spectroscopy and SDS-PAGE, and antigenicity was evaluated by immunoblotting and indirect ELISA with anti-Ara h 6 polyclonal antibody. Irradiation induced significant changes in the secondary and tertiary structures of Ara h 6, and the antigenicity of both purified Ara h 6 and WPPE were reduced upon increasing the irradiation doses. Moreover, a good correlation between the loss in α-helix and IgG binding to Ara h 6 was observed. This indicated that irradiation might be an efficient approach to reduce or eliminate peanut allergenicity.
    Food Chemistry 02/2013; 136(3-4):1141-7. DOI:10.1016/j.foodchem.2012.09.091 · 3.26 Impact Factor
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    ABSTRACT: Field amplified sample stacking (FASS) was combined with a simple, rapid, sensitive CE-ESI-MS method to achieve the on-line enrichment and simultaneous determination of Clenbuterol (CLE), Salbutamol (SAL), Terbutaline (TER) and Formoterol (FOR). Samples were diluted in deionized water, and electrokinetic injection (10kV×50s) was employed to carry out FASS. With FASS, the four β2-agonists had simultaneously baseline enhancement as much as 319, 332, 297 and 115 fold, respectively. Consequently, satisfactory LODs (S/N=3) of 0.08, 0.1, 0.1 and 0.5ng/mL for CLE, SAL, TER and FOR were obtained. The separation of the four analytes was performed at 22kV in ammonium acetate/ammonia (20mmol/L, pH 9.0), using 7.5mmol/L acetic acid in isopropanol/water 50/50% (v/v) as sheath liquid. In addition, an excellent linear response was obtained with RSD less than 1.3% for migration times and less than 6.7% for peak areas (n=5). The recoveries of spiked urine samples were in the range of 82.7-101% with RSD lower than 9.8%. The proposed method has been applied to analyze human urine samples successfully.
    Talanta 01/2013; 104C:97-102. DOI:10.1016/j.talanta.2012.11.041 · 3.51 Impact Factor
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    ABSTRACT: The aim of this research was to assess heat induced changes of the potential allergenicity and the structure of ovotransferrin (OVT). Changes in conformational structure of OVT were characterised by circular dichroism (CD) spectroscopy, ultraviolet (UV) absorption spectroscopy and fluorescence spectroscopy. A reversible unfolding structure was found at 55–60 C, followed by the loss of secondary structure at 70–80 C. Cleavage and rearrangements of disulphide bonds occurred when heated above 80 C. The indirect enzyme-linked immunosorbent assay (ELISA) of heat-treated OVT with egg allergic patients’ sera and specific rabbit polyclonal antibodies against native OVT showed that the potential allergenicity of OVT correlated well with the structural changes. Allergenicity increased with the unfolding of its structure, and decreased with the cleavage of disulphide bonds and the rearrangements of disulphide bonds. The results suggested that conformational changes of OVT induced by heat treatment significantly influenced the allergenicity of OVT, and the potential allergenicity of heated OVT is related to individual patient characteristics.
    Food Chemistry 03/2012; 131(2):603-610. DOI:10.1016/j.foodchem.2011.08.084 · 3.26 Impact Factor
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    ABSTRACT: We aim to map immunoglobulin G (IgG)‐binding linear epitopes on buffalo β‐lactoglobulin by prediction through bioinformatics analysis and screening from phage library. Five possible regions on buffalo β‐lactoglobulin were predicted as epitope candidates by LaserGene software and web service. Six mimic epitope regions, AA14‐20, AA26‐32, AA36‐42, AA70‐80, AA82‐86 and AA149‐156 were obtained by the panning of phage display peptide library with specific rabbit sera against buffalo β‐lactoglobulin with AA70‐80 and AA149‐156 as the major ones. Compared with the results of prediction and panning, 30% of predicted epitope regions accorded with the ones by panning, however, the 40% of panned epitopes were not predicted by bioformatics analysis. Additionally, two rabbit IgG‐binding regions on buffalo β‐lactoglobulin, AA134‐143(EKFDKALKAL) and AA149‐156 (LAFNPTQL), were found not to be reported on bovine β‐lactoglobulin. PRACTICAL APPLICATIONSMolecular biology and biochemical techniques have considerably advanced the knowledge of allergens and supported the characterization of isoforms and the determination of the primary, secondary and tertiary structures of these proteins. It has been explained that allergic disease is induced by the following mechanisms: Exogeneous antigens are processed by endosomal proteases to peptides in antigen presenting cells, and are presented to T cells by appropriate major histocompatability complex class II molecules present on the cell surface. For understanding of the mechanism of allergy, allergen epitopes should be known. So here we aim to map the epitopes of buffalo β‐lactoglobulin.
    Journal of Food Biochemistry 02/2012; 36(1). DOI:10.1111/j.1745-4514.2010.00502.x · 0.85 Impact Factor
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    ABSTRACT: A new pressure-assisted capillary electrochromatography coupled with electrospray ionization-mass spectrometry method using a silica-based monolithic column as separation media was developed for the analysis of β2-agonists in human urine. Experimental conditions including the mobile phase, separation voltage, assisted pressure, and sheath liquid were optimized for the analysis: mobile phase composed of 82% (v/v) ACN and 18% (v/v) 20mmol/L ammonium acetate (pH 6.0); separation voltage 25kV; assisted pressure 2bar; and the sheath liquid consisting of 7.5mmol/L acetic acid in isopropanol/water 50/50% (v/v) that was delivered at a flow rate of 3.0μL/min. Six β2-agonists were separated within 12.5min with LODs (defined as S/N=3) in the range of 0.25–2.0ng/mL. The absolute LODs of the developed method for analyzing six β2-agonists ranged from 5.75 to 46.0fg. Method repeatability of run-to-run and column-to-column was satisfactory. The recovery obtained from the analysis of spiked urine samples was between 88.2% and 106% with RSDs lower than 6.68%. The method was successfully applied to the analysis of real urine sample from volunteers.
    Talanta 06/2010; 81(4):1655-1661. DOI:10.1016/j.talanta.2010.03.020 · 3.51 Impact Factor
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    ABSTRACT: A new method for analyzing diuretics by capillary electrochromatography using poly (1-hexadecene-co-TMPTMA) monolithic column was established. Experimental conditions including the mobile phase, separation voltage, and injection condition were optimized for the analysis. Under optimized experimental conditions, six diuretics were separated within 11.0 min with the limits of detection (LODs) (S/N = 3) in the range of 0.35 - 0.65 microg/mL. The method showed good linearity (R2 > or = 0.990 8) in the range 1.15 and 86.0 microg/mL. The recoveries obtained from the analysis of spiked urine sample were between 81.9% and 105% with the relative standard deviations (RSDs) lower than 4.7%. It can be concluded that this new method possessed good repeatability and stability in analyzing diuretics, and was successfully applied to the analysis of real urine samples from volunteers. Therefore, this method could be applied to scanning diuretics in human urine samples.
    Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 03/2010; 28(3):253-9. DOI:10.3724/SP.J.1123.2010.00253
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    ABSTRACT: Buffalo -lactoglobulin in phosphate buffer (0.02 M, pH6.8) was adsorbed on DEAE-Sepharose Fast Flow gel, and eluted with a linear gradient of NaCl (0-0.5 M) in 0.02 M phosphate buffer, pH 6.8. A further purification was performed on Sephadex G-75 gel by loading a concentrated and dialyzed fraction of samples containing buffalo -lactoglobulin from ion-exchange chromatography, and seperating at a flow rate of 0.15 ml/min in 0.02 M phosphate buffer, pH 6.8. The purity of the isolated buffalo -lactoglobulin was above 90% in comparison to the standard bovine -lactoglobulin by SDS-PAGE and IEF-PAGE. The antigencity of the buffalo -lactoglobulin was evualuted by indirect ELISA, Western-blotting and inhibition ELISA with anti-buffalo and anti-bovine -lactoglobulin rabbit serum. The results showed that buffalo -lactoglobulin could be seperated and purified by anion-exchange chromatography combined with gel filtration chromatography, and with a well-preserved antigenicity.
    Journal of Biotechnology 10/2008; 136. DOI:10.1016/j.jbiotec.2008.07.1723 · 2.88 Impact Factor
  • Journal of Biotechnology 10/2008; 136. DOI:10.1016/j.jbiotec.2008.07.541 · 2.88 Impact Factor
  • Journal of Biotechnology 10/2008; 136. DOI:10.1016/j.jbiotec.2008.07.1710 · 2.88 Impact Factor

Publication Stats

47 Citations
33.32 Total Impact Points


  • 2008–2014
    • Nanchang University
      Nan-ch’ang-shih, Jiangxi Sheng, China
  • 2013
    • Fuzhou University
      • Department of Chemical Engineering
      Min-hou, Fujian, China