Expression of Outer Capsid Protein VP5 of Grass Carp Reovirus in E.coli and Analysis of its Immunogenicity

Grass carp reovirus (GCRV) is a tentative member of the Aquareovirus genus in the family Reoviridae. The mature virion comprises 11 dsRNA genomes enclosed by two concentric icosahedral proteins shells that is comprised of five core proteins and two outer capsid proteins. The genome sequence and 3D structure demonstrate there is a higher level of sequence homology in structural proteins between GCRV and mammalian orthoreoviruses (MRV) compared to other members of the family. To understand the pathogenesis of GCRV infection, the outer capsid protein VP5, a homology of the μ1 protein of MRV, was expressed in E.coli. It was found that the recombinant VP5 was highly expressed, and the expressed His-tag fusion protein was involved in the formation of the inclusion body. Additionally, specific anti-VP5 serum was prepared from purified protein and western blot demonstrated that the expressed protein was able to bind immunologically to rabbit anti GCRV particle serum and the immunogenicity was determined by ELISA assay. Additional experiments in investigating the functional properties of VP5 will further elucidate the role of the GCRV outer capsid protein VP5 during entry into host cells, and its interaction among viral proteins and host cells during the infection process.

Pharmacokinetic Disposition of Streptomycin Sulfate in Japanese Eel (<i>Anguilla japonica</i>) after Oral and Intramuscular Administrations

Pharmacokinetics and residue elimination of streptomycin sulfate (STR) are important in the determination of optimal dosage regimens and in establishing safe withdrawal periods in farmed fishes. The pharmacokinetics of STR was studied after a single dose (50 mg/kg) of intramuscular (i.m.) or oral gavage (p.o.) administration to Japanese eel (Anguilla japonica) in freshwater at 25°C. Eight fish per sampling point were examined after treatment. Plasma and muscle were collected and analyzed by high-performance liquid chromatography (HPLC) method with 0.05 μg/ml detection limit. The data of pharmacokinetics conformed to the two-compartment open model for intramuscular and one-compartment open model for oral administrations. After intramuscular administration, the elimination half-life (t1/2β) was calculated to be 11.346 h, the maximum plasma concentration (Cmax) to be 29.524 μg/ml, the time to peak plasma streptomycin concentration (Tmax) to be 0.218 h, and the area under the plasma concentration-time curve (AUC) to be 90.206 μg/ml?h. Following p.o. administration, the corresponding estimates were 13.239 h, 0.346 μg/ml, 11.960 h, and 12.356 μg/ml?h. After intramuscular administration, a therapeutic concentration of the drug was maintained for 12 hours in the plasma, however, a therapeutic level could not be achieved after oral administration, and the results suggest that the drug can be used clinically by intramuscular administration against streptomycin susceptible systemic infections in Japanese eel.