The coronavirus disease 2019 pandemic caused by the novel coronavirus SARS‐CoV‐2 (severe acute respiratory syndrome coronavirus 2) has claimed many lives worldwide. Wearing medical masks (MMs) or N95 masks ([N95Ms] namely N95 respirators) can slow the virus spread and reduce the infection risk. Reuse of these masks can minimize waste, protect the environment, and help solve the current imminent shortage of masks. Disinfection of used masks is needed for their reuse with safety, but improper decontamination can damage the blocking structure of masks. In this study, we demonstrated using the avian coronavirus of infectious bronchitis virus to mimic SARS‐CoV‐2 that MMs and N95Ms retained their blocking efficacy even after being steamed on boiling water for 2 hours. We also demonstrated that three brands of MMs blocked over 99% viruses in aerosols. The avian coronavirus was completely inactivated after being steamed for 5 minutes. Altogether, this study suggested that MMs are adequate for use on most social occasions and both MMs and N95Ms can be reused for a few days with steam decontamination between use.

The prevalence of avian H9N2 viruses throughout Asia, along with their demonstrated ability to infect mammals, puts them high on the list of influenza viruses with pandemic potential for humans. In this study, we investigated whether H9N2 viruses could infect farmed minks. First, we conducted a serological survey for avian influenza virus antibodies on a random sample of the field-trial population of farmed minks. Then we inoculated farmed minks with A/Chicken/Hebei/4/2008 H9N2 viruses and observed the potential pathogenicity of H9N2 virus and virus shedding in infected minks. H9 influenza antibodies could be detected in most farmed minks with a higher seropositivity, which indicated that farmed minks had the high prevalence of exposure to H9 viruses. After infection, the minks displayed the slight clinical signs including lethargy and initial weight loss. The infected lungs showed the mild diffuse pneumonia with thickened alveolar walls and inflammatory cellular infiltration. Influenza virus detection showed that viruses were detected in the allantoic fluids inoculated supernatant of lung tissues at 3 and 7 days post-infection (dpi), and found in the nasal swabs of H9N2-infected minks at 3–11 dpi, suggesting that H9N2 viruses replicated in the respiratory organ, were then shed outwards. HI antibody test showed that antibody levels began to rise at 7 dpi. Our data provided the serological and experimental evidences that strongly suggested farmed minks under the natural state were susceptible to H9N2 viral infection and might be the H9N2 virus carriers. It is imperative to strengthen the H9N2 viral monitoring in farmed minks and pay urgent attention to prevent and control new influenza viruses pandemic prevalence.

How conformational signals initiated from one end of the integrin are transmitted to the other end remains elusive. At the ligand-binding βI domain, the α1/α1′-helix changes from a bent to a straightened α-helical conformation upon integrin headpiece opening. We demonstrated that a conserved glycine at the α1/α1′ junction is critical for maintaining the bent conformation of the α1/α1′-helix in the resting state. Mutations that facilitate α1/α1′-helix unbending rendered integrin constitutively active. However, mutations that block the α1/α1′-helix unbending abolished soluble ligand binding upon either outside or inside stimuli. Such mutations also blocked ligand-induced integrin extension from outside the cell, but had no effect on talin-induced integrin extension from inside the cell. In addition, integrin mediated cell spreading, F-actin stress fiber and focal adhesion formation, and focal adhesion kinase activation were also defective in these mutant integrins, although the cells still adhered to immobilized ligands at a reduced level. Our data establish the structural role of the α1/α1′ junction that allows relaxation of the α1/α1′-helix in the resting state and transmission of bidirectional conformational signals by helix unbending upon integrin activation.

Feline panleukopenia, caused by feline parvovirus (FPV), is a highly infectious disease characterized by leucopenia and hemorrhagic gastroenteritis that severely affects the health of large wild Felidae. In this study, tiger FPV virus-like particles (VLPs) were developed using the baculovirus expression system. The VP2 gene from an infected Siberian tiger (Panthera tigris altaica) was used as the target gene. The key amino acids of this gene were the same as those of FPV, whereas the 101st amino acid was the same as that of canine parvovirus. Indirect immunofluorescence assay (IFA) results demonstrated that the VP2 protein was successfully expressed. SDS-PAGE and Western blotting (WB) results showed that the target protein band was present at approximately 65 kDa. Electron micrograph analyses indicated that the tiger FPV VLPs were successfully assembled and were morphologically similar to natural parvovirus particles. The hemagglutination (HA) titer of the tiger FPV VLPs was as high as 1:2¹⁸. The necropsy and tissue sections at the cat injection site suggested that the tiger FPV VLPs vaccine was safe. Antibody production was induced in cats after subcutaneous immunization, with a >1:2¹⁰ hemagglutination inhibition (HI) titer that persisted for at least 12 months. These results demonstrate that tiger FPV VLPs might provide a vaccine to prevent FPV-associated disease in the tiger.