Preparation of Artificial Antigen and Egg Yolk-derived Immunoglobulin(IgY) of Citrinin for Enzyme-Linked Immunosorbent Assay

Objective To prepare artificial antigens and anti-citrinin egg yolk-derived immunoglobulin （IgY） to build an enzyme-linked immunosorbent assay （ELISA） for citrinin （CTN）. Methods 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. Results 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·mL^-1, with a good linearity ranging 20-640 ng·mL^-1. Conclusion Artificial antigens of CTN can be successfully synthesized. The established ELISA can be used to determine CTN- contaminated samples.

Ubc9 expression predicts chemoresistance in breast cancer

Ubiquitin-conjugating enzyme 9(Ubc9),the sole conjugating enzyme for sumoylation,regulates protein function and plays an important role in tumorigenesis.Whether Ubc9 is involved in the chemoresistance of breast cancer remains unknown.In this study,we aimed to evaluate the contribution of Ubc9 in the chemoresistance of breast cancer.Immunohistochemistry(IHC) was used to examine the expression level of Ubc9.Chi-square test,Wilcoxon test,and one-way ANOVA were applied to analyze the relationship between Ubc9 expression,clinicopathologic features,and clinical response to neoadjuvant chemotherapy.The significance of variables for survival was analyzed by the Cox proportional hazards model in a multivariate analysis.Kaplan-Meier survival curves were plotted and log-rank test was performed.The proportion of Ubc9-positive cells was higher in invasive ductal carcinoma than in normal breast tissues [(48.48 ± 17.94)% vs.(5.82 ± 2.80)%,P < 0.001].High Ubc9 expression was associated with poor differentiation(χ2 = 6.538,P = 0.038),larger tumor size(χ2 = 4.701,P = 0.030),advanced clinical stage(χ2 = 4.651,P = 0.031),lymph node metastasis(χ2 = 9.913,P = 0.010),basal-like phenotype(χ2 = 8.660,P = 0.034),and poor clinical response to neoadjuvant chemotherapy(χ2 = 11.09,P = 0.001).The expected 6-year cumulative disease-free survival rate was 87.32% in patients with low Ubc9 expression compared to 68.78% in those with high Ubc9 expression(χ2 = 4.289,P = 0.038).These data indicate that high Ubc9 expression correlates with poor response to chemotherapy and poor clinical prognosis.