This study aims to establish an indirect ELISA method for detecting RVFV antibodies u-sing recombinant proteins of Rift Valley fever virus(RVFV)Gn protein Ⅱ-Ⅲ structural domains as the encapsulated antigen which was expressed by the Escherichia coli(E.coli)expression sys-tem.The gene sequences encoding the Ⅱ and Ⅲ subdomains of RVFV Gn protein were inserted in-to pET-30a(+)to construct the recombinant plasmid pET-RVFV Gn-D Ⅱ-Ⅲ.After transforma-tion of the recombinant plasmid into DE3(BL21)competent cells,the recombinant Gn-D Ⅱ-Ⅲ protein was induced with IPTG and purified using affinity chromatography.An indirect ELISA method for the detection of RVFV antibodies was developed using purified recombinant protein as coating antigen and SPA-HRP as the enzyme-labelled secondary antibody.Western blot analysis confirmed that the RVFV Gn-D Ⅱ-Ⅲ protein was successfully expressed.The optimal expression conditions for RVFV Gn-D Ⅱ-Ⅲ protein were induced with 0.8 mmol/L IPTG at 37 ℃ for 5 h.The Gn-D Ⅱ-Ⅲ protein was purified using affinity chromatography with a purity of 91.9％,and the purified protein was used as the encapsulated antigen to develop an ELISA assay for RVFV anti-bodies.The specificity evaluation showed that the method specifically detected RVFV-positive sera and did not cross-react with sera positive for West Nile virus(WNV),Ebola virus(EBOV),Mar-burg virus(MARV)and tick-borne encephalitis virus(TBEV).When the RVFV Gn-D Ⅲ-Ⅲ posi-tive serum was diluted to 6 400 times,the test result still showed positive results,demonstrating the method had good sensitivity.The repeatability evaluation results indicated that the variation co-efficients for both intra-and inter-batch responses was less than 10％,indicating that the method had good repeatability.In conclusion,the RVFV Gn-D Ⅱ-Ⅲ protein was successfully expressed u-sing the E.coli expression system.The purified recombinant Gn-D Ⅱ-Ⅲ protein was used as the encapsulated antigen to develop an indirect ELISA assay for RVFV antibodies,which provides a preliminary basis for the diagnosis of RVF and the research and development of RVF vaccines.

To establish an indirect enzyme linked immunosorbent assay(ELISA)method for the detection of Zaire Ebola virus(ZEBOV)specific antibodies,the full-length of ZEBOV GP1 gene was amplified by PCR and cloned into pET-30a(+)vector to generate the pET-30a(+)-GP1 plasmid.After expressed in the E.coli expression system,the purified GP1 protein was used as coating antigen to establish the indirect ELISA method for detection of ZEBOV antibody.The con-ditions including concentration of coating antigen and serum dilution were determined by chess-board titration.Specificity,sensitivity,and reproducibility of the established ELISA detection meth-od were evaluated.GP1 protein was successfully prepared by prokaryotic expression,and was used as the coatingantigen for indirect ELISA.By optimizing the reaction conditions,the optimal concen-tration of the coating antigen was determined to be 0.5 g/L;the optimal dilution of serum was cal-culated to be 1∶3 200;the optimal dilution of enzyme-labeled secondary antibody was measured to be 1∶20 000.The established method exhibited excellent specificity,sensitivity,and reproducibili-ty.In the present study,the GP1 protein was successfully expressed in the E.coli expression sys-tem and the high purity GP1 protein was used as the coating protein to establish an indirect ELISA assay for ZEBOV antibody.This method is highly specific,sensitive,and reproducible,which provides technical support for the fur-ther study of the biological function of GP1 and the detection of ZEBOV antibody in serum.

Objective: To investigate the effect of neurite outgrowth inhibitor extracellular peptide residues 1-40 (NEP1-40) combined with poly (lactic-co-glycolic acid) (PLGA) and gelatin electrospun fiber membrane on facial nerve repair in rats. Methods: According to the principle of random grouping, 108 male SD rats were divided into four groups (n = 27 in each group, approved by the ethics committee), namely, the sham group, control group, PLGA group, and NEP1-40 + PLGA group. A facial nerve fracture model was established for all of the groups except for the sham group. The control group received no further treatment, the PLGA group and the NEP1-40+PLGA group were supported by PLGA membrane, and the NEP1-40+PLGA group received one immediate local injection of NEP1-40 (5 μg/μL) at a dose of 10 μL. Facial nerve function analysis, electrophysiological examination, transmission electron microscope observation, HE staining, and immunohistochemical staining of myelin marker S100β and axonal marker β3-tubulin were used to evaluate the recovery of injured facial nerves of rats at 2, 4 and 8 weeks. Results : At 8 weeks, the facial nerve function score of the NEP1-40+PLGA group was better than that of the control group and PLGA group (P < 0.001), and facial nerve function was significantly restored. Electrophysiological examination of nerve action potentials at the injured facial nerve showed that the amplitude in the NEP1-40+PLGA group was higher than that of the control group and PLGA group (P < 0.001), but there was no significant difference in latency and conduction velocity results between the groups (P > 0.05). At 2, 4, and 8 weeks, transmission electron microscopy showed that the number of myelinated nerve fibers and myelin sheath thickness in the cross-section of the injured facial nerve in the NEP1-40+PLGA group were greater than those in the other groups (P < 0.05). At 8 weeks, HE staining showed that the facial nerves in the control group had partially recovered, but the overall cell distribution was uneven and the boundary with surrounding tissues was slightly blurred. In contrast, the NEP1-40+PLGA group had a relatively uniform cell distribution and a clearer boundary with surrounding tissues. At 2, 4, and 8 weeks, the immunohistochemical results showed that in the cross-section of the injuried facial nerve, NEP1-40 increased the expression of neural markers S100 β and β3-tubulin, especially β3-tubulin, which was close to normal levels (P > 0.05) Conclusion NEP1-40 is beneficial for the generation of new myelin sheaths and axons at the site of injury, and it can promote the repair and regeneration of injured facial nerves to a certain extent, thus accelerating the recovery of injured nerve function.

To understand the current epidemiological status and biological characteristics of avian paramyxoviruses(APMV)in wild birds in China,a total of 1 384 fecal samples of wild birds were collected in eight provinces(autonomous regions),including Ningxia,in 2023,to detect avian pa-ramyxovirus infections by viral isolation and RT-PCR.Positive samples were subjected to F gene sequence amplification and genetic evolutionary analyses.The results showed that 10 strains of APMV were isolated and identified from 1 384 wild bird feces samples with a positive rate of 0.72％.Out of the 10 strains,4 strains were APMV-1,which was in the same branch to the Ameri-can goose APMV-1 strain and had the homology ranging from 93％to 97.3％.Three strains of APMV-4 were in the same branch with the Russian duck APMV-4 strain and the Russian pintail APMV-4 strain,with homology ranging from 99.1％to 99.5％.Three strains were APMV-6,they were in the same branch with the Russian ruddy bladdered duck APMV-6 strain,with homology ranging from 98.7％to 99.20％.The intracerebral inoculatable pathogenicity index(ICPI)of the four strains for 1-day-old chicks ranged from 0 to 0.48,which was low in pathogenicity for chick-ens.The above results enriches the epidemiological information and the biological characteristics of avian paramyxovirus in wild birds in China,which provides a reference for the early warning,scien-tific prevention and control of this disease.

Feline herpesvirus type Ⅰ(FHV-1)was used as the vector.The gI and gE genes of FHV-1 were replaced with the feline calicivirus(FCV)VP1 gene and the red fluorescent protein(mCherry)gene by CRISPR/Cas9 systems and homologous recombination technology,and the re-combinant virus strain FHV △gI&gE/VP1-mCherry+was successfully rescued.The recombinant virus strain was purified by plaque assay.The biological characteristics and genetic stability of the recombinant virus were analyzed by indirect immunofluorescence assay,plaque morphological anal-ysis,and PCR.The results of the indirect immunofluorescence identification showed that the re-combinant virus FHV △gI&gE/VP1-mCherry+could express the VP1 protein in F81 cells,and the growth characteristics of the recombinant virus were not significantly different from those of the parent virus FHV-1.The plaque morphology and staining results indicated that the area of the plaque formed by the recombinant virus was smaller than that of the parent virus,suggesting that the spread ability of the recombinant virus between cells was reduced after the deletion of the gI and gE genes.The result of PCR showed that the VP1 gene could still be detected after 15 succes-sive passages of the recombinant virus,indicating that the recombinant virus had good genetic stability.In this study,the recombinant virus strain expressing the FCV VP1 protein was successfully prepared,which will lay a foundation for the development of engineered FCV and FHV-1 vaccine.

Moloney leukemia virus 10(MOV10)gene knockout(MKO)mouse neuro 2a(N2a)cell lines was constructed by CRISPR/Cas9(clustered regularly interspaced short palindromic repeat/CRISPR-associated protein 9)gene editing technology.First,a recombinant plasmid pMD18T-U6-sgRNA expressing MOV10 gene-specific guide RNA(sgRNA)was constructed,and then pMD18T-U6-sgRNA and pMJ920-Cas9-eGFP were co-transfected into N2a.The results showed that the MKO N2a cell line had normal cell activity and cell proliferation ability.The infection test of the MKO N2a cell line was carried out using the rabies virus(RABV)and vesicular stomatitis virus(VSV)of the Rhabdoviridae family.The results showed that the replication level of the Rhabdoviridae virus in the MKO N2a cell line was significantly enhanced.The results showed that a MKO N2a cell line was successfully constructed in this study,which provided a preliminary basis for the exploration of the biological function and antiviral mechanism of MOV10 and the develop-ment of a recombinant viral vector vaccine with RABV/VSV as the vector.

This study aims to establish an indirect ELISA method for detecting RVFV antibodies u-sing recombinant proteins of Rift Valley fever virus(RVFV)Gn protein Ⅱ-Ⅲ structural domains as the encapsulated antigen which was expressed by the Escherichia coli(E.coli)expression sys-tem.The gene sequences encoding the Ⅱ and Ⅲ subdomains of RVFV Gn protein were inserted in-to pET-30a(+)to construct the recombinant plasmid pET-RVFV Gn-D Ⅱ-Ⅲ.After transforma-tion of the recombinant plasmid into DE3(BL21)competent cells,the recombinant Gn-D Ⅱ-Ⅲ protein was induced with IPTG and purified using affinity chromatography.An indirect ELISA method for the detection of RVFV antibodies was developed using purified recombinant protein as coating antigen and SPA-HRP as the enzyme-labelled secondary antibody.Western blot analysis confirmed that the RVFV Gn-D Ⅱ-Ⅲ protein was successfully expressed.The optimal expression conditions for RVFV Gn-D Ⅱ-Ⅲ protein were induced with 0.8 mmol/L IPTG at 37 ℃ for 5 h.The Gn-D Ⅱ-Ⅲ protein was purified using affinity chromatography with a purity of 91.9％,and the purified protein was used as the encapsulated antigen to develop an ELISA assay for RVFV anti-bodies.The specificity evaluation showed that the method specifically detected RVFV-positive sera and did not cross-react with sera positive for West Nile virus(WNV),Ebola virus(EBOV),Mar-burg virus(MARV)and tick-borne encephalitis virus(TBEV).When the RVFV Gn-D Ⅲ-Ⅲ posi-tive serum was diluted to 6 400 times,the test result still showed positive results,demonstrating the method had good sensitivity.The repeatability evaluation results indicated that the variation co-efficients for both intra-and inter-batch responses was less than 10％,indicating that the method had good repeatability.In conclusion,the RVFV Gn-D Ⅱ-Ⅲ protein was successfully expressed u-sing the E.coli expression system.The purified recombinant Gn-D Ⅱ-Ⅲ protein was used as the encapsulated antigen to develop an indirect ELISA assay for RVFV antibodies,which provides a preliminary basis for the diagnosis of RVF and the research and development of RVF vaccines.

To establish an indirect enzyme linked immunosorbent assay(ELISA)method for the detection of Zaire Ebola virus(ZEBOV)specific antibodies,the full-length of ZEBOV GP1 gene was amplified by PCR and cloned into pET-30a(+)vector to generate the pET-30a(+)-GP1 plasmid.After expressed in the E.coli expression system,the purified GP1 protein was used as coating antigen to establish the indirect ELISA method for detection of ZEBOV antibody.The con-ditions including concentration of coating antigen and serum dilution were determined by chess-board titration.Specificity,sensitivity,and reproducibility of the established ELISA detection meth-od were evaluated.GP1 protein was successfully prepared by prokaryotic expression,and was used as the coatingantigen for indirect ELISA.By optimizing the reaction conditions,the optimal concen-tration of the coating antigen was determined to be 0.5 g/L;the optimal dilution of serum was cal-culated to be 1∶3 200;the optimal dilution of enzyme-labeled secondary antibody was measured to be 1∶20 000.The established method exhibited excellent specificity,sensitivity,and reproducibili-ty.In the present study,the GP1 protein was successfully expressed in the E.coli expression sys-tem and the high purity GP1 protein was used as the coating protein to establish an indirect ELISA assay for ZEBOV antibody.This method is highly specific,sensitive,and reproducible,which provides technical support for the fur-ther study of the biological function of GP1 and the detection of ZEBOV antibody in serum.

Feline herpesvirus type Ⅰ(FHV-1)was used as the vector.The gI and gE genes of FHV-1 were replaced with the feline calicivirus(FCV)VP1 gene and the red fluorescent protein(mCherry)gene by CRISPR/Cas9 systems and homologous recombination technology,and the re-combinant virus strain FHV △gI&gE/VP1-mCherry+was successfully rescued.The recombinant virus strain was purified by plaque assay.The biological characteristics and genetic stability of the recombinant virus were analyzed by indirect immunofluorescence assay,plaque morphological anal-ysis,and PCR.The results of the indirect immunofluorescence identification showed that the re-combinant virus FHV △gI&gE/VP1-mCherry+could express the VP1 protein in F81 cells,and the growth characteristics of the recombinant virus were not significantly different from those of the parent virus FHV-1.The plaque morphology and staining results indicated that the area of the plaque formed by the recombinant virus was smaller than that of the parent virus,suggesting that the spread ability of the recombinant virus between cells was reduced after the deletion of the gI and gE genes.The result of PCR showed that the VP1 gene could still be detected after 15 succes-sive passages of the recombinant virus,indicating that the recombinant virus had good genetic stability.In this study,the recombinant virus strain expressing the FCV VP1 protein was successfully prepared,which will lay a foundation for the development of engineered FCV and FHV-1 vaccine.

Moloney leukemia virus 10(MOV10)gene knockout(MKO)mouse neuro 2a(N2a)cell lines was constructed by CRISPR/Cas9(clustered regularly interspaced short palindromic repeat/CRISPR-associated protein 9)gene editing technology.First,a recombinant plasmid pMD18T-U6-sgRNA expressing MOV10 gene-specific guide RNA(sgRNA)was constructed,and then pMD18T-U6-sgRNA and pMJ920-Cas9-eGFP were co-transfected into N2a.The results showed that the MKO N2a cell line had normal cell activity and cell proliferation ability.The infection test of the MKO N2a cell line was carried out using the rabies virus(RABV)and vesicular stomatitis virus(VSV)of the Rhabdoviridae family.The results showed that the replication level of the Rhabdoviridae virus in the MKO N2a cell line was significantly enhanced.The results showed that a MKO N2a cell line was successfully constructed in this study,which provided a preliminary basis for the exploration of the biological function and antiviral mechanism of MOV10 and the develop-ment of a recombinant viral vector vaccine with RABV/VSV as the vector.