Preparation of artificial antigen and egg yolk-derived immunoglobulin (IgY) of citrinin for enzyme-linked immunosorbent assay / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To prepare artificial antigens and anti-citrinin egg yolk-derived immunoglobulin (IgY) to build an enzyme-linked immunosorbent assay (ELISA) for citrinin (CTN).</p><p><b>METHODS</b>CTN was conjugated with bovine serum albumin (BSA), ovalbumin (OVA) with formaldehyde condensation method to prepare artificial antigens and identified by ultraviolet (UV) spectrometry and Infrared (IR) spectrometry. Artificial antigens for CTN and anti-CTN IgY were purified with polyethylene glycol two-step precipitation method and identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). ELISA with IgY was established. Cross-reactivity of IgY with various structural similarities to CTN and possible co-occurrence with CTN in agricultural commodities were studied.</p><p><b>RESULTS</b>UV and IR absorption spectra suggested that CTN was correlated with the carrier protein of BSA or OVA. SDS-PAGE patterns showed that the anti-CTN IgY was almost pure with a molecular weight of approximate 100 KD. The indirect competitive ELISA showed that the detection limit of CTN was 10 ng x mL(-1), with a good linearity ranging 20-640 ng x mL(-1).</p><p><b>CONCLUSION</b>Artificial antigens of CTN can be successfully synthesized. The established ELISA can be used to determine CTN- contaminated samples.</p>

Comparative proteomic analysis of B. henselae Houston and B. henselae Marseille by two-dimensional gel electrophoresis / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the protein difference between B. henselae Houston and B. henselae Marseille by two-dimensional gel electrophoresis.</p><p><b>METHOD</b>Protein samples were prepared by vorterx, ultrasonic treatment, and centrifugation. Protein concentrations were determined by Bradford method. Protein difference was compared by the first IEF and the second SDS-polyacrylamide gel electrophoresis.</p><p><b>RESULTS</b>Protein concentrations in samples of Bartonella henselae Houston and Bartonella henselae Marseille were 2.117 microg/microL and 2.200 microg/microL respectively. Sample protein of 40 microg for IPG strips loading was perfect. The results of 2-DE in pH 4 to 7 IPG strips showed that the total protein spots of Bartonella henselae Houston and Bartonella henselae Marseille were 375 and 379 respectively, 95% of the spots were the same between the two strains of Bartonella henselae.</p><p><b>CONCLUSION</b>The procedure of 2-DE may prove successful for the proteomic analysis of Bartonella henselae. Bartonella henselae Houston and Bartonella henselae Marseille are different genotypes.</p>

Studies on purification of methamidophos monoclonal antibodies and comparative immunoactivity of purified antibodies / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To purify Methamidophos (Met) monoclonal antibodies with two methods and compare immune activity of purified antibodies.</p><p><b>METHOD</b>Caprylic acid ammonium sulphate precipition (CAASP) method and Sepharose protein-A (SPA) affinity chromatography method were used to purify Met monoclonal antibodies, UV spectrum scanning was used to determine protein content and recovery of purified antibodies, sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the purity of purified antibodies, and enzyme-linked immunosorbent assay (ELISA) was used to determine immune activity of purified antibodies.</p><p><b>RESULTS</b>Antibody protein content and recovery rate with CAASP method were 7.62 mg/mL and 8.05% respectively, antibody protein content and recovery rate with SPA method were 6.45 mg/mL and 5.52% respectively. Purity of antibodies purified by SPA method was higher than that by CAASP method. The half-maximal inhibition concentration (IC50) of antibodies purified by SPA to Met was 181.26 microg/mL, and the linear working range and the limit of quantification (LOD) were 2.43-3896.01 microg/mL and 1.03 microg/mL, respectively. The IC50 of antibodies purified by CAASP to Met was 352.82 microg/mL, and the linear working range and LOD were 10.91-11412.29 microg/mL and 3.42 microg/mL, respectively.</p><p><b>CONCLUSION</b>Antibodies purified by SPA method are better than those by CAASP method, and Met monoclonal antibodies purified by SPA method can be used to prepare gold-labelled testing paper for analyzing Met residue in vegetable and drink water.</p>