Development of colloidal gold test strip based on the BsVg819 gene fragment of vitellogenin of Bostrichthys sinensis for the detection of vitellogenin in multiple fish species.

As an environmental estrogen biomarker, the yolk precursor, vitellogenin (Vtg) is widely used in the assessment of estrogen pollution in aquatic environment. Currently, the detection of Vtg in plasma is mainly achieved by enzyme-linked immunosorbent assay (ELISA) method based on Vtg antibodies. However, due to differences in the immunological epitopes of Vtg from various species, Vtg antibodies have low universality. Therefore, identifying a universal antigenic epitopes of Vtg from multiple fish species and designing a tools that can be applied in the field can promote the use of Vtg in monitoring estrogenic contamination in aquatic environments. Bioinformatics analysis of the Vtg of Bostrichthys sinensis revealed that the protein is highly conserved in structure. The results of PCR showed that the amino acid sequence encoded by the BsVg819 gene fragment from the Vtg gene of Bostrichthys sinensis could have more than 97% similarity with the amino acid sequences of the PCR products of ten fish species. Development of a colloidal gold immunochromatographic test strip using recombinant proteins was expressed in BsVg819 gene fragments. The test strip was able to detect Vtg in the plasma of untreated female Bostrichthys sinensis and ten different female fish species. Vtg in the plasma of juvenile Bostrichthys sinensis treated with estrogen is elevated and can be detected by test strips. The results show that the test strips have good usability. Compared to ELISA, the strip is prospective for field applications. It provides a portable tool for future rapid detection of estrogenic contamination in the field.