ABSTRACT
OBJECTIVE:To establish a method for the determination of related substances in bifonazole raw material. METH-ODS:HPLC method was performed on the column of Kromasil C18 with mobile phase of methanol-0.02 mol/L phosphoric acid(ad-justed pH to 7.5 with triethylamine)(70:30,V/V)at a flow rate of 1.0 ml/min,detection wavelength was 258 nm,volume injection was 20 μl,and the column temperature was 40 ℃. RESULTS:The linear range was 0.05-0.25 μg/ml for bifonazole(r=0.9996), 0.05-0.25 μg/ml for impurity A(bifonol)(r=0.9997)and 0.05-0.25 μg/ml for impurity B(4-C isomer)(r=0.9995);the detec-tion limits were 8.2 ng/ml,7.5 ng/ml and 8.4 ng/ml,and the quantification limits were 27.1 ng/ml,24.7 ng/ml and 27.8 ng/ml,re-spectively;RSDs of precision and reproducibility tests were lower than 1%;recovery of impurity B was 95.13%-101.29%(RSD=1.89%,n=9);both impurity A and impurity B were were detected in the 3 batches of samples. CONCLUSIONS:The method is accurate,sensitive and reproducible,and can be used for the determination of the related substances in bifonazole raw material.
ABSTRACT
A truncated mutant of the Open Reading Frame 2 (ORF2, aa384-606) was amplified from cDNA of genotype IV hepatitis E virus (HEV) by polymerase chain reaction (PCR), subcloned to expression plasmid pTO-T7, and expressed in Escherichia coli. SDS-PAGE and Western blotting were used to detect and identify the recombinant protein, namely rP24. After washing of inclusion bodies, dissolving in denaturing agents, refoldeding by dialysis, ion exchange chromatography and gel chromatography, dynamic light scatter was used to study the hydrated radius of rP24. Western blotting was applied to detect the immunoreactivity of rP24, and mouse immunity test and indirect enzyme linked immunosorbent assay (ELISA) were applied to evaluate the immunogenicity and the detection rate of HEV positive and negative serum. SDS-PAGE and Western blotting show that rP24 was highly expressed in the form of inclusion bodies after induction, and had strong immunoreactivity to monoclonal antibody (McAb) 15B2. After a multi-step purification of rP24, Western blotting indicated that the purified rP24 also had strong immunoreactivity to neutralizing McAb 8C11 and HEV positive serum, suggesting that rP24 simulated the nature structure of HEV capsid protein. Dynamic light scatter demonstrated that the average hydration radius of purified rP24 was 7.48 nm. The mouse immunity test showed that the purified rP24 also had good immunogenicity, and the period of serum antibodies converted from negative to positive was very short, but the antibodies maintained more than 20 weeks. Indirect ELISA tests showed that the detection rate of was the same as anti-HEV-IgG diagnostic kit (Wan Tai corporation). Taken together, the rP24 simulated the neutralizing epitopes of natural HEV, and had strong immunoreactivity and immunogenicity. It provided a basis for the further investigation of the difference of infection mechanism between genotype I and genotype IV HEV.
Subject(s)
Animals , Mice , Antibodies, Monoclonal , Antibodies, Neutralizing , Blotting, Western , Capsid Proteins , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Epitopes , Genotype , Hepatitis E virus , Mutant Proteins , Open Reading Frames , Recombinant ProteinsABSTRACT
Hepatitis B virus (HBV) infection can cause the severe threat to the health of the people around the world. It depends upon the development of efficient diagnostic reagent and vaccine to prevent the prevalence of HB. In this study, we constructed the high expression recombinant Pichia pastoris and performed the screening tests in shake flasks to obtain the optimal values of several key fermentation parameters. Based on their effects on the growth and expression level of recombinant strains, FBS was the optimal industrial medium. The optimal values for the dissolve oxygen (DO), the final concentrations of methanol and the pH values were 50 mL, 1% (V/V) and 5.4-6.0, respectively. The optimal values of the parameters simulated in shake flasks were successfully scaled up to 10 L bioreactors to achieve high-throughput production: 310 OD600 in biomass and 27 mg/L in recombinant HBsAg. The expressed recombinant HBsAg in P. Pastoris was confirmed by SDS-PAGE and Western blotting. Electron microscopy examination showed that the purified protein could be self-assembled to 22 nm virus-like particles. The results provided a basis for industrial scale-up production of diagnostic reagent and vaccine of next generation against HB.