Virus diversity, wildlife-domestic animal circulation and potential zoonotic viruses of small mammals, pangolins and zoo animals.

Wildlife is reservoir of emerging viruses. Here we identified 27 families of mammalian viruses from 1981 wild animals and 194 zoo animals collected from south China between 2015 and 2022, isolated and characterized the pathogenicity of eight viruses. Bats harbor high diversity of coronaviruses, picornaviruses and astroviruses, and a potentially novel genus of Bornaviridae. In addition to the reported SARSr-CoV-2 and HKU4-CoV-like viruses, picornavirus and respiroviruses also likely circulate between bats and pangolins. Pikas harbor a new clade of Embecovirus and a new genus of arenaviruses. Further, the potential cross-species transmission of RNA viruses (paramyxovirus and astrovirus) and DNA viruses (pseudorabies virus, porcine circovirus 2, porcine circovirus 3 and parvovirus) between wildlife and domestic animals was identified, complicating wildlife protection and the prevention and control of these diseases in domestic animals. This study provides a nuanced view of the frequency of host-jumping events, as well as assessments of zoonotic risk.

Using Self-Assembling ADDomer Platform to Display B and T Epitopes of Type O Foot-and-Mouth Disease Virus.

Foot-and-mouth disease virus (FMDV) is a highly contagious and devastating virus that infects cloven-hoofed livestock and various wildlife species. Vaccination is the best measure to prevent FMD. ADDomer, as a kind of non-infectious adenovirus-inspired nanoparticle, has the advantage of high thermal stability. In this study, two dominant B-cell antigen epitopes (residues 129~160 and 200~213) and a dominant T-cell antigen epitope (residues 16~44) of type O FMDV were inserted into the ADDomer variable loop (VL) and arginine-glycine-aspartic acid (RGD) loop. The 3D structure of the recombinant protein (ADDomer-RBT) was simulated by homology modeling. First, the recombinant proteins were expressed by the baculovirus expression system and detected by western blot and Q Exactive mass spectrometry. Then the formation of VLPs was observed under a transmission electron micrograph (TEM). Finally, we evaluated the immunogenicity of chimeric VLPs with a murine model. Bioinformatic software analysis preliminarily corroborated that the chosen epitopes were successfully exposed on the surface of ADDomer VLPs. The TEM assay demonstrated the structural integrity of the VLPs. After immunizing, it was found that FMDV-specific antibodies can be produced in mice to induce humoral and cellular immune responses. To sum up, the ADDomer platform can be used as an effective antigen carrier to deliver antigen epitopes. This study presents one of the candidate vaccines to prevent and control FMDV.

Construction of bifunctional electrochemical biosensors for the sensitive detection of the SARS-CoV-2 N-gene based on porphyrin porous organic polymers.

In this study, a novel porphyrin-based porous organic polymer (POP) was constructed using 5,10,15,20-tetramine (4-aminophenyl) porphyrin (TAPP) and 5,5'-diformyl-2,2'-bipyridine (DPDD) as organic ligands via a solvothermal method (represented as TAPP-DPDD-POP). Then, it was utilized as a bifunctional scaffold for constructing a sensitive sensing strategy toward the nucleocapsid phosphoprotein (N-gene) of SARS-CoV-2. The obtained TAPP-DPDD-POP is composed of nanospheres with a size of 100-300 nm and possesses a highly conjugated and π-π stacking network. The coexistence of the porphyrin and bipyridine moieties of TAPP-DPDD-POP afforded considerable electrochemical activity and a strong binding interaction toward the SARS-CoV-2 N-gene-targeted antibody and targeted the aptamer strands of the N-gene. The TAPP-DPDD-POP-based aptasensor and immunosensor were manufactured for the sensitive analysis of SARS-CoV-2 N-gene, and exhibited the limit of detection (LOD) of 0.59 fg mL-1 and 0.17 fg mL-1, respectively, within the range of 0.1 fg mL-1 to 1 ng mL-1 of N-gene. The sensing performances of both the TAPP-DPDD-POP-based aptasensor and immunosensor were better than those of existing electrochemical biosensors for analyzing the N-gene, accompanied with excellent stability, high selectivity and reproducibility. The TAPP-DPDD-POP-based aptasensor and immunosensor were then employed to detect the N-gene from various environments, including human serum, river water, and seafoods. This work provides a new method of using an electrochemically active POP to sensitively and selectively analyze SARS-CoV-2 in diverse environments.