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African swine fever virus (ASFV) is a large, double-stranded DNA virus that causes a fatal disease in pigs, posing a threat to the global pig industry. Whereas some ASFV proteins have been found to play important roles in ASFV–host interaction, the functional roles of many proteins are still largely unknown. In this study, we identified I73R , an early viral gene in the replication cycle of ASFV, as a key virulence factor. Our findings demonstrate that pI73R suppresses the host innate immune response by broadly inhibiting the synthesis of host proteins, including antiviral proteins. Crystallization and structural characterization results suggest that pI73R is a nucleic-acid-binding protein containing a Zα domain. It localizes in the nucleus and inhibits host protein synthesis by suppressing the nuclear export of cellular messenger RNA (mRNAs). While pI73R promotes viral replication, the deletion of the gene showed that it is a nonessential gene for virus replication. In vivo safety and immunogenicity evaluation results demonstrate that the deletion mutant ASFV-GZΔ I73R is completely nonpathogenic and provides effective protection to pigs against wild-type ASFV. These results reveal I73R as a virulence-related gene critical for ASFV pathogenesis and suggest that it is a potential target for virus attenuation. Accordingly, the deletion mutant ASFV-GZΔ I73R can be a potent live-attenuated vaccine candidate.

African swine fever (ASF) is a highly contagious disease of domestic and wild pigs caused by the African swine fever virus (ASFV). The current research on ASF vaccines focuses on the development of naturally attenuated, isolated, or genetically engineered live viruses that have been demonstrated to produce reliable immunity. As a result, a genetically engineered virus containing five genes deletion was synthesized based on ASFV Chinese strain GZ201801, named ASFV-GZΔI177LΔCD2vΔMGF. The five-gene-deleted ASFV was safe and fully attenuated in pigs and provides reliable protection against the parental ASFV strain challenge. This indicates that the five-gene-deleted ASFV is a potential candidate for a live attenuated vaccine that could control the spread of ASFV.

In 2018, a disease characterized by splenic hemorrhage and necrosis killed ducks in a duck farm in Guangxi province, China. A duck reovirus strain was isolated from the tissues of the dead ducks by inoculating duck embryos and BHK-21 cells. Electron microscopy of the cultured the isolate showed that the viral particles were nearly round in shape and approximately 70 nm in diameter, and they were designated DRV-GL18. Sequence analysis showed that the GL18 strain viral genome was 23,419 nt in length and had 10 dsRNA segments. Phylogenetic analysis of cDNA amplicons of segments encoding the protein σC which are outer capsid proteins showed that the isolate belongs to the branch of the epidemic strains of duck reovirus. The Recombination Detection Program (RDP) and SimPlot program analyses suggested potential genetic recombination events in the M2 segments. Pathogenicity experiments revealed that GL18 produced severe hemorrhaging in livers and necrosis in the spleen of infected SPF ducklings. A death rate of 50% in the experimental ducklings was calculated during the first 7 d, and the rest of the ducklings were observed to undergo spleen necrosis. These data suggested that GL18 is a duck reovirus isolate with severer pathogenicity, and it could be a candidate for development of vaccine. This is the first reported isolation of duck reovirus from mature ducks.

As the sand mass flux increases from zero at the leading edge of a saltating surface to the equilibrium mass flux at the critical fetch length, the wind flow is modified and then the relative contribution of aerodynamic and bombardment entrainment is changed. In the end the velocity, trajectory and mass flux profile will vary simultaneously. But how the transportation of different sand size groups varies with fetch distance is still unclear. Wind tunnel experiments were conducted to investigate the fetch effect on mass flux and its distribution with height of the total sand and each size group in transportation. The mass flux was measured at six fetch length locations (0.5, 1.2, 1.9, 2.6, 3.4 and 4.1 m) and at three free-stream wind velocities (8.8, 12.2 and 14.5 m/s). The results reveal that the total mass flux and the mass flux of each size group with height can be expressed by q=aexp(−bh), where q is the sand mass flux at height h, and a and b are regression coefficients. The coefficient b represents the relative decay rate. Both the relative decay rates of total mass flux and each size group are independent of fetch length after a quick decay over a short fetch. This is much shorter than that of mass flux. The equilibrium of the relative decay rate cannot be regarded as an equilibrium mass flux profile for aeolian sand transport. The mass fluxes of 176.0, 209.3 and 148.0 μm size groups increase more quickly than that of other size groups, which indicates strong size-selection of grains exists along the fetch length. The maximal size group in mass flux (176.0 μm) is smaller than the maximal size group of the bed grains (209.3 μm). The relative contribution of each size group to the total mass flux is not monotonically decreasing with grain size due to the lift-off of some small grains being reduced due to the protection by large grains. The results indicate that there are complex interactions among different size groups in the developmental process of aeolian sand transport and more attention should be focused on the fetch effect because it has different influences on the total mass flux, the mass flux profile and its relative decay rate.

Novel duck reovirus (NDRV), the prototype strain of the species Avian orthoreovirus (ARV), is associated with high mortality in Pekin ducklings. σC is an outer capsid protein encoded by the S1 genome segment of NDRV which mediates attachment to host cells. Our previous studies using immunoprecipitation and mass spectrometry found that σC coprecipitated with some host proteins including Translocation-associated membrane protein 1 (TRAM1). However, the interaction between σC and TRAM1 has not been further confirmed experimentally. In this study, we utilized coimmunoprecipitation assays, glutathione S-transferase pull-down, and confocal microscopy to confirm the interaction between σC and TRAM1. In addition, knockdown of TRAM1 using siRNA and overexpression of TRAM1 gene were conducted to explore its effect on virus replication. The result showed that TRAM1 silencing benefits while overexpression inhibits viral replication. This study confirms the important role TRAM1 during NDRV infection which can help develop new approaches for NDRV disease prevention and control.

Duck adenoviruses (DAdVs) include serotype 1 (DAdV-1) in the genus Atadenovirus and serotypes 2-4 (DAdV-2, 3, and 4) in the genus Aviadenovirus. DAdV-3 was initially isolated from Chinese Muscovy ducks in 2014, whereby the infected ducks exhibited yellowing and hemorrhaging in the liver, along with slight pericardial effusion, swelling, and hemorrhaging in the kidneys. In recent years, duck adenovirus infections have appeared in Muscovy duck farms in Fujian, Zhejiang, Anhui, Guangdong, and other places in China. They have an incidence rate of 40 to 55% and a mortality rate of 35 to 43%, resulting in great losses to the duck breeding industry. In this study, 7 DAdV-3 strains, designated as TZ193, FJPT20161124, GX20170519, FJZZ, GDMM, AHAQ, and GDHS were isolated from Muscovy ducks in different provinces of China during 2016–2019, and their complete genomics were sequenced. Their genomes all exhibited significant deletions in ORF67, which also had G to A transitions at the 41st and 977th nt positions, resulting in a stop codon. The pathogenicity of TZ193, a novel isolate of DAdV-3, was investigated in Muscovy ducks. TZ193 caused characteristic lesions of swelling as well as hemorrhagic liver and kidney in the infected ducklings. Moreover, the mortality rate of TZ193 in 5-day-old domestic ducks was 100%. Our data provide concrete evidence for the identification of the DAdV-3 novel variant mutant in China, which effects increased mortality in ducks. This highlights the necessity for monitoring the specific molecular epidemiology of novel DAdV-3 mutants and the development of new vaccines in the future.

During epidemiological surveillance of Feline calicivirus (FCV) isolates in Shanghai, China, a natural mutant of FCV, designated SH1909, was successfully isolated from a stray cat. The complete genome sequence of SH1909 was determined in this study. Sequence comparison and analysis showed that thirteen unique aa residues substitutions and single-aa insertion of N or Y were observed in SH1909, which indicated that SH1909 was a novel and natural mutant of FCV. Interestingly, phylogenetic analysis based on LC-VP1 showed SH1909 could be clustered into an independent evolutionary branch with some Chinese isolates and was more distantly related to vaccine strains, indicating its potential to escape from vaccine-elicited immunity. According to the predicted B-cell epitopes of LC-VP1, amino acid mutation sites and positive selective sites, peptide C (aa sites: 445–460) and, peptide D (aa sites: 425–440) located in the hypervariable regions of LC-VP1, may result in the decreased immunological protection. Moreover, amino acid sites 439 and 449 may be responsible for the potential immune escape of SH1909. This study provides an important insight into genetic variations of FCV and vaccine development.

In this paper, the content and speciation of Cd, Cr, Pb, As, Cu, Zn and Ni in 87 groups of soil samples collected by grid method were determined by Inductively Coupled Plasma-Atomic Emission Spectrometry, to explore the speciation characteristics and ecological risk status of heavy metals in surface soil around Qinghai Lake. The results show that: Cd and Pb, compared with Cr, As, Cu, Zn and Ni, in the surface soil around Qinghai Lake are the most seriously polluted, Heavy metal speciation analysis showed that the proportion of weak acid soluble components of Cd was relatively high, with strong mobility and high environmental risk. The reducible components of Zn and Pb account for a relatively high proportion, while the oxidizable components of Cu, Cd and Pb account for a relatively high proportion. The high percentage of residual Cr, Ni and As indicates that they are relatively stable. The extractable content of Cd, Pb and Zn is relatively high, and their activities are strong, which have a great impact on the food chain. The results of Inductively Coupled Plasma-Atomic Emission Spectrometry and the ratio of secondary phase and primary phase showed that Cd and Pb had more serious ecological risk than other heavy metals. According to the results of soil speciation and ecological risk assessment of heavy metals around Chinese and foreign lakes, although the speciation characteristics of heavy metals are different, the pollution of Cd is relatively large. To sum up, heavy metal pollution in soil around Qinghai Lake area has occurred, and there is a serious ecological risk, so it is urgent to take corresponding monitoring and formulate treatment plan.

Duck short beak and dwarf syndrome (SBDS) is a viral infectious disease caused by novel duck parvovirus (NDPV). It has brought serious economic losses to the Chinese duck industry in recent years. Currently, there exists no effective vaccine against this disease. In this study, we developed an inactivated virus vaccine based on NDPV-DS15 for SBDS. Immune efficacy was evaluated in 112 ducks, which were randomly divided into vaccination, challenge control, vaccination-challenge, and blank control groups (n = 28 each). Clinical characteristics, antibodies, viral excretion, viremia, and pathological changes were monitored and analyzed. No morbidity or death was observed in the immunized ducks, which showed normal weight and good mental state. High levels of serum antibodies (OD450 nm: ~0.63) were detected in ducks immunized with inactivated vaccine at 7 days post-vaccination (dpv), and the amount of virus neutralizing antibodies increased from 1:23 to 1:28.5 from 7 dpv to 42 dpv. The anal swab, serum, and tissue viral load tests showed that vaccination could significantly inhibit the replication of NDPV in immunized ducks. Moreover, NDPV could not be isolated from the spleens of immunized or vaccination-challenged ducks. Our results show that the developed inactivated NDPV vaccine, administered in an oil emulsion adjuvant, possesses good immunogenicity and represents a potentially powerful tool for SBDS prevention and control.

Duck short beak and dwarfism syndrome (SBDS) is a viral infectious disease caused by novel goose parvovirus (NGPV), which has been responsible for serious economic losses to the Chinese duck industry in recent years. Currently, there is no effective vaccine against this disease. In this study, we developed an inactivated virus vaccine candidate for SBDS based on NGPV strain DS15 isolated from a duck in China. Immune efficacy was evaluated in 112 ducks, which were randomly divided into vaccination, challenge-control, vaccination-challenge, and blank control groups (28 per group). Clinical characteristics, antibodies, virus excretion, viremia, and pathological changes were monitored. No morbidity or death was observed in the immunized ducks, which showed normal weight and a good mental state. High levels of serum antibodies (optical density at 450 nm of ~ 0.63) were detected in ducks immunized with the inactivated vaccine at 7 days post-vaccination (dpv), and the titer of virus-neutralizing antibodies increased from 1:2

Goose nephritic astrovirus (GNAstV) has recently been identified, which causes kidney swelling and visceral gout in goslings. However, the pathological changes in kidney tissue due to GNAstV infection have not yet been described. In the study, fifty goslings were orally infected with GNAstV, and fifty goslings received PBS as a control. Kidney tissue was collected at different days following infection (dpi) to assess the injury. GNAstV infection reduced body weight, increased the relative weight of the kidney, and increased serum uric acid and creatinine levels. GNAstV was found within renal epithelial cells, and the viral load in the kidney peaked at 7 dpi. Pale and swollen kidney tissue was observed in infected goslings, especially at 5 and 7 dpi. GNAstV infection caused degeneration and necrosis of renal epithelial cells, structural destruction of the brush border, glycogen deposition in the glomerular mesangium, increased fibrosis, and infiltration of inflammatory cells into the renal interstitium. Moreover, swollen mitochondria, broken mitochondrial ridges, autophagosomes, and autophagolysosomes were observed under ultrahistopathological examination. GNAstV infection increased levels of LC3B, ATG5, and Beclin 1, and decreased p62, and downregulated WT1 mRNA and upregulated desmin mRNA. At early stages, GNAstV infection decreased expression of intercellular junction-related genes, including ZO-1, occludin, claudin-10, and catenin-α2. In conclusion, GNAstV infection causes renal epithelial cell autophagy, destruction of brush border and intercellular junctions, podocyte damage, and increased fibrosis, ultimately resulting in damage to the kidney.

The variability and the intrinsically high mutation rate of canine parvovirus type 2(CPV-2) increased the diversity of CPV-2 in canine populations. Since the first occurrence of CPV-2, three antigenic variants (2a, 2b and 2c) were detected and distributed worldwide. CPV-2c infection has been detected and increasingly reported in China. Here, a CPV-2c strain CPV-SH1516 was isolated and its complete genome sequence was first characterized. Compared with other CPV-2c isolates, CPV-2c isolates from China continued to evolve into divergent CPV-2c variants with specific unique amino acid substitutions under purifying selection. Emergence of CPV-2c isolates from China was driven by the unique gradual point mutations in key sites of VP2 rather than introduction from outside China. Combining sequence comparison with phylogenetic analysis based on the amino acid sequences of VP2, the vast majority of CPV-2c isolates from China formed a monophyletic cluster and CPV-SH1516 was a representative isolate of CPV-2c circulating in China. Overall, our study provides valuable insight into the evolutionary mechanism of CPV-2c.

During the period of the epidemiological surveillance of Feline calicivirus (FCV) isolates, a natural mutant of FCV, designated SH1909, was successfully isolated from a stray cat in Shanghai, China. The complete genome sequence of SH1909 was also determined in this study. Sequence comparison and analysis show that thirteen unique aa residues substitutions and single-aa insertion of N or Y were observed in SH1909 when compared with other FCV isolates. Phylogenetic analysis showed that SH1909 was assigned into a major evolutionary branch and distantly related to vaccine strains. These results indicated that SH1909 was a natural mutant of FCV circulating in China, which has the potential to escape from immunity of FCV vaccine.

A new canine picornavirus (CanPV) variant, designated as dog/SH1901/CHN/2019, was detected in a pool of various canine fecal samples in the mainland of China using a viral metagenomic analysis, and its nearly complete genome sequence was determined and analyzed. Sequence analyses revealed that it had a standard picornavirus genome organization, a type I internal ribosome entry site (IRES) in the 5'UTR. However, dog/SH1901/CHN/2019 has generated a serial of unique aa mutations and 7aa insertion when compared with the closely related CanPVs. Phylogenetic analysis and pairwise sequence comparisons based on the P1, 2C, 3C, and 3D protein sequences showed that dog/SH1901/ CHN/2019 was closely related to CanPV strains 244 F, 325 F and 6D, which clustered into an independent evolutionary clade and distantly related to CanPV strain A128thr of the genus Mischivirus, which indicated the unclassified CanPV strains may belong to a novel species or genus in the family Picornaviridae. This study extends our knowledge on the evolution and genetic diversity of CanPVs.

In order to reveal the pollution characteristics and sources of heavy metals in surface soil of the region around the Qinghai Lake in Tibet Plateau, improve the prevention awareness and measures of local residents and urge the local government to implement necessary prevention and control measures, nine heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in the surface soil samples of the region around the Qinghai Lake have been collected and analyzed. The methods such as statistic method, geo-accumulation index method, Nemerow index method, potential ecological risk index method, human health risk evaluation method and positive matrix factor analysis model (PMF) have been used to evaluate pollution characteristics and potential risks and analyze the sources of heavy metals. The results are shown below. First, the average contents of heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in soil are 11.73 &plusmn, 3.78, 0.62 &plusmn, 1.40, 12.38 &plusmn, 3.68, 41.35 &plusmn, 13.01, 19.33 &plusmn, 8.92, 546.96 &plusmn, 159.28, 21.18 &plusmn, 7.04, 21.86 &plusmn, 6.61 and 63.51 &plusmn, 19.71 mg&middot, kg&minus, 1, respectively. Compared with the background values of the soil environment in Qinghai Province, it can be seen that there is an accumulation of these heavy metals to varying degrees, which is the most serious in Cd, Co and Pb. Second, the analysis of the geo-accumulation index and Nemerow index indicates that the heavy metals in the surface soil of the region around the Qinghai Lake have reached the level of heavy pollution, mainly polluted by Cd, and the accumulation of heavy metal pollution in the north, south, southwest and southeast of the study area is more serious. Third, the results of potential ecological risk evaluation show that the study area as a whole is classified as an area with high ecological risk, and Cd contributes the most to the overall risk. In fact, the heavy metals in the soil of the study area produce no noncarcinogenic and carcinogenic health risks to human health, and children and adults may be exposed to these risks by the mouth. Finally, the PMF results reveal that the sources of heavy metals in the study area include the sources of agricultural production, the nature, coal burning and transportation, with a contribution rate of 43.10%, 25.34%, 19.67% and 11.89%, respectively.

Rabbit haemorrhagic virus (RHDV) is a highly infectious and fatal pathogen to rabbits. Classic RHDV is mainly pathogenic to adult rabbits; however, it is not lethal to young rabbits. Since 2010, a RHDV variant has become prevalent in Europe and the Australian continent. This variant, which was named RHDV2 (GI.2/RHDVb), is highly infectious and fatal to both adult and young rabbits; moreover, its host range is broader than that of classic RHDV (GI.1/G1-6). In May 2020, the first RHDV2 case in China was reported. Here, we report and describe the first RHDV2 case in China. We amplified its complete genome sequence (named SC20-01 strain). The phylogenetic tree showed that the SC20-01 strain is mostly related to two strains isolated in Europe, which indicated that it might have spread from Europe to China. Moreover, Recombination Detection Program software showed that the SC20-01 strain is a G6/RHDV2 recombinant strain. Animal experiments showed that the SC20-01 strain is a highly fatal pathogen to specific-pathogen-free (SPF) rabbits and induces typical clinical symptoms of RHD. Our findings highlight RHDV2 emergence in China and its potential to spread widely. There is a need for more attention on the RHDV2 threat in China and the development of new diagnostic methods and vaccines for preventing the spread of RHDV2.

A novel duck picornavirus, designated as duck/AH15/CHN/2015, was isolated and identified from Cherry Valley ducks with short beak and dwarfism syndrome in 2015 in Anhui province of China. Duck/AH15/CHN/2015 has the highest degree of amino acid sequence identity (approximately 43 %) with duck hepatitis A viruses (DHAV) Complete genome analysis revealed that duck/AH15/CHN/2015 possesses a typical picornavirus-like genomic organization, 5' UTR-L-P1 (VP0-VP3-VP1)-P2 (2A1-2A2- 2B-2C)-P3 (3A-3B-3C-3D)-3'UTR-poly (A). The 5'UTR contains a potential type IV internal ribosome entry site, while a conserved "barbell"-like structure is found at the 3'UTR, which is similar to DHAV. Compared to the closest related DHAVs, two unrelated 2A proteins were predicted in duck/AH15/CHN/2015, while three unrelated 2A proteins were presented in DHAVs. Based on the amino acid identity comparison and phylogenetic analysis of P1, 2C, and 3CD (3C and 3D), duck/AH15/CHN/2015 was closely related to but distinct from DHAVs, and it was proposed to be a member of a novel species in the genus Avihepatovirus of the family Picornaviridae.

Novel duck reovirus (NDRV), the prototype strain of the species Avian orthoreovirus (ARV), is currently an infectious agent for ducks. Studies on NDRV replication and pathogenesis have been hampered by the lack of an available reverse-genetics system. In this study, a plasmid-based reverse-genetics system that is free of helper viruses has been developed. In this system, 10 full-length gene segments of wild-type NDRV TH11 strain are transfected into BSR-T7/5 cells that express bacteriophage T7 RNA polymerase. Production of infectious virus was shown by the inoculation of cell lysate derived from transfected cells into 10-day-old duck embryos. The in vivo growth kinetics and infectivity of the recombinant strains were identical to those of the wild-type strain. These viruses grew well and were genetically stable both in vitro and in vivo. Altogether, these results show the successful production of an infectious clone for NDRV. The infectious clone reported will be further used to elucidate the mechanisms of host tropism, viral replication and pathogenesis, as well as immunological changes induced by NDRV.

A rapid and accurate diagnosis of mixed viral infections is important for providing timely therapeutic interventions. The aim of this study was to develop a highly sensitive and specific method for the simultaneous detection of canine distemper virus (CDV), canine parvovirus (CPV) and canine coronavirus (CCV) in mixed infections by combining the high specificity of a dual priming oligonucleotide (DPO) primer system with the high sensitivity of a nanoparticle-assisted PCR (nanoPCR) assay. Under the optimised assay conditions, the multiplex DPO-nanoPCR assay developed using DPO primers was 100-fold more sensitive than the multiplex PCR assay using conventional primers. The detection limits of the multiplex DPO-nanoPCR assay for the recombinant plasmids containing the cloned CDV, CPV and CCV target sequences were 5.4 × 102, 6.5 × 102 and 1.6 × 102 copies in a 25 μL assay, respectively. No cross-reaction with other canine viruses was observed. This is the first reported use of a multiplex nanoPCR assay with the DPO primer system for the simultaneous detection of CDV, CPV and CCV in mixed infections. The high sensitivity and specificity of the assay indicated its potential for use in clinical diagnosis and field surveillance of animal epidemics.

Small ruminant morbillivirus (SRMV) is a highly contagious and economically important viral disease of small domestic and wild ruminants. Difficulty with its stable proliferation in ovis aries-derived cells has led to a relative lag in the study of its natural immunity and pathogenesis. Here we report the antiviral properties of ZAP against SRMV, a single-stranded negative-stranded RNA virus of the genus Morbillivirus. ZAP expression was significantly induced in sheep endometrial epithelial cells following SRMV infection. ZAP inhibited SRMV replication in cells after infection, while its overexpression in Vero-SLAM cells significantly increased their resistance to SRMV replication. The ZAP protein co-localized with SRMV RNA in the cytoplasm and ZAP-responsive elements were mapped to the 5' untranslated region of SRMV nucleocapsid, phosphoprotein, matrix, and fusion. In summary, ZAP confers resistance to SRMV infection by directly targeting viral RNA and inhibiting viral replication. Our findings further extend the ranges of viral targets of ZAP and help elucidate the mechanism of SRMV replication.

A field canine parvovirus (CPV) strain, CPV-SH14, was previously isolated from an outbreak of severe gastroenteritis in Shanghai in 2014. The complete genome of CPV-SH14 was determined by using PCR with modified primers. When compared to other CPV-2 strains, several insertions, deletions, and point mutations were identified in the 5' and 3' UTR, with key amino acid (aa) mutations (K19R, E572K in NS1 and F267Y, Y324I and T440A in VP2) also being observed in the coding regions of CPV-SH14. These results indicated that significant and unique genetic variations have occurred at key sites or residues in the genome of CPV-SH14, suggesting the presence of a novel genetic variant of new CPV-2a. Phylogenetic analysis of the VP2 gene revealed that CPV-SH14 may have the potential to spread worldwide. In conclusion, CPV-SH14 may be a novel genetic variant of new CPV-2a, potentially with a selective advantage over other strains.

Currently, both goose astrovirus (GoAstV) and goose-origin Newcastle disease virus (NDV) are widely infectious agents for goslings. There is no vaccine for GoAstV. Capsid protein can elicit a neutralizing antibody in human astroviruses (HAstV). Molecular analysis of the genomic region encoding the capsid protein(ORF2) of goose astrovirus has revealed that it contains neutralizing epitopes. Goose-origin NDV is also an infectious agent. A wide range of NDV strains exist that can be commonly used as vaccine vectors. In the present study, the fusion protein cleavage site RRQKR↓F in a backbone of the virulent goose-origin NDV SH-12 was changed into an avirulent motif GRQGR↓L. The modified goose-origin NDV recombinant vaccine virus expressing the Capsid protein (Cap) of GoAstV was generated as a bivalent vaccine using a reverse-genetics approach. The recombinant virus, rNDV/GoAstV-Cap, was attenuated and similar growth dynamics, cytopathic effects, and virus titers in vitro were maintained when compared to the LaSota strain. Expression of the GoAstV-Cap protein in rNDV/GoAstV-Cap infected cells was detected by an immunofluorescence assay and Western blotting. Goslings inoculated with rNDV/GoAstV-Cap showed no apparent signs of disease and induced GoAstV-Cap-specific immune responses and NDV-specific serum antibody responses to a LaSota vaccination control. Complete protection against a pathogenic GoAstV challenge and avelogenic NDV challenge was conferred. The results of the study suggested that rNDV/GoAstV-Cap viruses have the potential to be the safe, stable, and effective bivalent vaccines.

Rabbit hemorrhagic disease virus (RHDV) is an important member of the caliciviridae family. Currently, no suitable tissue culture system is available for proliferating RHDV, which limits the study of its pathogenesis. To bypass this obstacle, we established a cell line, RK13-VPg, stably expressing the VPg gene with a lentivirus packaging system in this study. In addition, the recently constructed RHDV replicon in our laboratory provided an appropriate model for studying the pathogenesis of RHDV without in vitro RHDV propagation and culture. Using this RHDV replicon and RK13-VPg cell line, we further demonstrated that the presence of VPg protein is essential for efficient translation of an RHDV replicon. Therefore, the RK13-VPg cell line is a powerful tool for studying the replication and translation mechanisms of RHDV.

Current studies have revealed the immune effects of graphene oxide (GO) and have utilized them as vaccine carriers and adjuvants. However, GO easily induces strong oxidative stress and inflammatory reaction at the site of injection. It is very necessary to develop an alternative adjuvant based on graphene oxide derivatives for improving immune responses and decreasing side effects. Carnosine (Car) is an outstanding and safe antioxidant. Herein, the feasibility and efficiency of ultrasmall graphene oxide decorated with carnosine as an alternative immune adjuvant were explored. OVA@GO-Car was prepared by simply mixing ovalbumin (OVA, a model antigen) with ultrasmall GO covalently modified with carnosine (GO-Car). We investigated the immunological properties of the GO-Car adjuvant in model mice. Results show that OVA@GO-Car can promote robust and durable OVA-specific antibody response, increase lymphocyte proliferation efficiency, and enhance CD4(+) T and CD8(+) T cell activation. The presence of Car in GO also probably contributes to enhancing the antigen-specific adaptive immune response through modulating the expression of some cytokines, including IL-6, CXCL1, CCL2, and CSF3. In addition, the safety of GO-Car as an adjuvant was evaluated comprehensively. No symptoms such as allergic response, inflammatory redness swelling, raised surface temperatures, physiological anomalies of blood, and remarkable weight changes were observed. Besides, after modification with carnosine, histological damages caused by GO-Car in lung, muscle, kidney, and spleen became weaken significantly. This study sufficiently suggest that GO-Car as a safe adjuvant can effectively enhance humoral and innate immune responses against antigens in vivo.

In the present work, a multifunctional nanomaterial, methylene blue-incorporated folate-functionalized Fe3O4/mesoporous silica core/shell magnetic nanoparticles, has been developed. Firstly, highly biocompatible monodisperse superparamagnetic Fe3O4@mSiO2 core/shell nanoparticles with mesoporous silica shells were synthesized. Then these particles were coated with the covalently bonded biocompatible polymer poly(ethylene glycol) (PEG) and modified with the cancer targeting ligand folic acid (FA). Finally, the water-soluble photosensitizer methylene blue (MB) was loaded into the mesoporous silica shell. Systematic experiments were performed to carefully evaluate the physical and chemical properties, cytotoxicity and cellular uptake of the multifunctional nanomaterial.

As ferrite nanoparticles (MFe2O4) have been widely used in biomedical field, their safety evaluation has been paid great attention both in vitro and in vivo. In this paper, the ultra-small MFe2O4 (M = Fe, Mn, Co) nanoparticles with the average size less than 5 nm were prepared by thermal decomposition method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and vibrating sample magnetometry (VSM). The toxic effect on human lung epithelial A549 cells treated with MFe2O4 nanoparticles at the different concentrations was evaluated in vitro. Mitochondrial function (MTT assay), cellular morphology, reactive oxygen species (ROS), superoxide dismutase (SOD), membrane lipid peroxidation (LPO) and glutathione (GSH) were assessed as toxicity end points. The results showed that the cytotoxicity of ultra-small MFe2O4 nanoparticles was in a dose- and time-dependent manner. Moreover, ultra-small Fe3O4 nanoparticles were found to be nearly non-toxic in A549 cells, while MnFe2O4 nanoparticles exhibited cytotoxic effects, and CoFe2O4 nanoparticles exerted higher cytotoxic effects among the three studied particles at the same concentration.

The fact that rabbit hemorrhagic disease virus (RHDV), an important member of the Caliciviridae family, cannot be propagated in vitro has greatly impeded the progress of investigations into the mechanisms of pathogenesis, translation, and replication of this and related viruses. In this study, we have successfully bypassed this obstacle by constructing a mutant RHDV (mRHDV) by using a reverse genetics technique. By changing two amino acids (S305R,N307D), we produced a specific receptor-recognition motif (Arg-Gly-Asp; called RGD) on the surface of the RHDV capsid protein. mRHDV was recognized by the intrinsic membrane receptor (integrin) of the RK-13 cells, which then gained entry and proliferated as well as imparted apparent cytopathic effects. After 20 passages, the titers of RHDV reached 1 × 104.3 50% tissue culture infectious dose (TCID50)/ml at 72 h. Furthermore, mRHDV-infected rabbits showed typical rabbit plague symptoms and died within 48–72 h. After immunization with inactivated mRHDV, the rabbits survived wild-type RHDV infection, indicating that mRHDV could be a candidate virus strain for producing a vaccine against RHDV infection. In summary, this study offers a novel strategy for overcoming the challenges of proliferating RHDV in vitro. Because virus uptake via specific membrane receptors, several of which specifically bind to the RGD peptide motif, is a common feature of host cells, we believe that this the strategy could also be applied to other RNA viruses that currently lack suitable cell lines for propagation such as hepatitis E virus and norovirus.

Cancer theranostics, the ability to simultaneously diagnose and treat cancer, has become one of the major driving forces in nanobiotechnology. In the present work, a multifunctional system, methylene blue-incorporated folate-functionalized Fe3O4/mesoporous silica core–shell magnetic nanoparticles (MNPs), for simultaneous near-infrared (NIR) fluorescence imaging and targeting photodynamic therapy (PDT) has been developed. The core Fe3O4 MNPs offers the function of magnetically guided drug delivery, the mesoporous silica shell acts as an efficient drug loaded carrier, the photosensitizer methylene blue (MB) exhibits excellent NIR fluorescence imaging and PDT efficiency, and the folic acid (FA) can effectively enhance the delivery of MB to the targeting cancer cells, which overexpress the folate receptor. The results indicated that the multifunctional system could effectively be used in NIR fluorescence imaging. Moreover, it exhibited a synergistic effect of magnetic targeted PDT of cancer under NIR laser irradiation. Thus, the multifunctional system is promising for simultaneous cancer diagnosis and therapy.

Novel duck reovirus (NDRV) disease emerged in China in 2011 and continues to cause high morbidity and about 5.0 to 50% mortality in ducklings. Currently there are no approved vaccines for the virus. This study aimed to assess the efficacy of a new vaccine created from the baculovirus and sigma C gene against NDRV. In this study, a recombinant baculovirus containing the sigma C gene was constructed, and the purified protein was used as a vaccine candidate in ducklings. The efficacy of sigma C vaccine was estimated according to humoral immune responses, cellular immune response and protection against NDRV challenge. The results showed that sigma C was highly expressed in Sf9 cells. Robust humoral and cellular immune responses were induced in all ducklings immunized with the recombinant sigma C protein. Moreover, 100% protection against lethal challenge with NDRV TH11 strain was observed. Summary, the recombinant sigma C protein could be utilized as a good candidate against NDRV infection.

Peste des petits ruminants (PPR), an acute and highly contagious disease, affects sheep, goats, and some small ruminants. The hemagglutinin (H) glycoprotein of the PPR virus (PPRV) is considered important for inducing protective immune responses. In this study, a suicidal DNA vaccine based on the Semliki Forest virus (SFV) replicon was constructed and tested for its ability to induce immunogenicity in a mouse model. For this, the H gene of PPRV was cloned and inserted into pSCA1, an SFV replicon vector. The resultant plasmid named pSCA1-H was then transfected into BHK-21 cells following which the antigenicity of the expressed protein was confirmed by Western blotting and immunofluorescence. The pSCA1-H plasmid was then injected intramuscularly into BALB/c mice thrice at 2-week intervals. To evaluate the immunogenicity of pSCA1-H, specific antibodies and neutralizing antibodies against PPRV-H were measured using an indirect enzyme-linked immunosorbent assay and a microneutralization test, respectively. Cell-mediated immune responses were also examined using a lymphocyte proliferation assay. The results showed that pSCA1-H could express the H protein in BHK-21 cells. Specific antibodies, neutralizing antibodies, and lymphocyte proliferation responses were all induced in mice. Thus, this suicidal DNA vaccine could be a promising new approach for vaccine development against PPR.