Abstract: Described herein are recombinant Newcastle disease viruses (“NDVs”) comprising a packaged genome, wherein the packaged genome comprises a transgene comprising a nucleotid sequence encoding a SARS-CoV-2 spike protein or nucleocapsid protein. Also described herein are recombinant NDVs comprising a packaged genome, wherein the packaged genome comprises a transgene encoding a chimeric F protein, wherein the chimeric F protein comprises a SARS-CoV-2 spike protein ectodomain and NDV F protein transmembrane and cytoplasmic domains. The recombinant NDVs and compositions thereof are useful for the immunizing against SARS-CoV-2 as well as the prevention of COVID-19.

Abstract: An active or inactivated recombinant vaccine against COVID-19 is described that comprises a Newcastle disease viral vector and a pharmaceutically acceptable carrier, adjuvant and/or excipient, characterized in that the viral vector is a virus capable of generating a cellular immune response that has a SARS-CoV-2 exogenous nucleotide sequence inserted,

Abstract: In one aspect, provided herein are mutated influenza virus neuraminidase polypeptides, wherein the mutated influenza virus neuraminidase polypeptides comprise a first cytoplasmic domain, a first transmembrane domain, a first stalk domain, and a first globular head domain of a first neuraminidase of a first influenza virus with an insertion of 15 to 45 or 1 to 50 amino acid residues in the first stalk domain of the first neuraminidase. In another aspect, provided herein is an influenza virus comprising such a mutated influenza virus neuraminidase polypeptide, a genome comprising a nucleotide sequence encoding such a mutated influenza virus neuraminidase polypeptide or both. In another aspect, provided herein is an immunogenic composition comprising such an influenza virus, and optionally an adjuvant.

Abstract: In one aspect, provided herein is a mosaic influenza virus hemagglutinin (HA) polypeptide comprising an influenza A virus HA ectodomain of an influenza A virus strain HA, wherein the HA ectodomain comprises an HA stem domain of the influenza A virus strain HA and an HA globular head domain of the influenza A virus strain HA, wherein the HA globular head domain of the influenza A virus strain HA has been engineered to comprise one or more amino acid substitutions in one, two, three, four or all of the antigenic sites. In another aspect, provided herein are immunogenic compositions comprising such a mosaic influenza virus HA polypeptide or an influenza A virus comprising such a mosaic influenza virus HA polypeptide. In yet another aspect, provided herein are methods for immunizing a subject against an influenza A vims in a subject comprising administering such an immunogenic composition to the subject.

Abstract: The present invention relates to a dual-arm clamping type holder for transmission electron microscopy grids and preparation method thereof. The preparation method comprises: firstly manufacturing a frame with two adjacent arms located on a same plane and have a clamping structure by a hard material; then putting the frame in a molten adhering liquid so that the frame is dipped with the adhering liquid; and finally, taking out the frame dipped with the adhering liquid, and waiting for the adhering liquid to solidify into adhering layers along the arms. The dual-arm clamping type holder manufactured by the method of the present invention comprises a frame and adhering layers; and the adhering layers adhere to the inner sides of the clamping structure between the two adjacent arms of the frame.

Abstract: The present invention relates to a dual-arm clamping type holder for transmission electron microscopy grids and preparation method thereof. The preparation method comprises: firstly manufacturing a frame with two adjacent arms located on a same plane and have a clamping structure by a hard material; then putting the frame in a molten adhering liquid so that the frame is dipped with the adhering liquid; and finally, taking out the frame dipped with the adhering liquid, and waiting for the adhering liquid to solidify into adhering layers along the arms. The dual-arm clamping type holder manufactured by the method of the present invention comprises a frame and adhering layers; and the adhering layers adhere to the inner sides of the clamping structure between the two adjacent arms of the frame.