Cross-species transmission and host range genes in poxviruses.

The persistent epidemic of human mpox, caused by mpox virus (MPXV), raises concerns about the future spread of MPXV and other poxviruses. MPXV is a typical zoonotic virus which can infect human and cause smallpox-like symptoms. MPXV belongs to the Poxviridae family, which has a relatively broad host range from arthropods to vertebrates. Cross-species transmission of poxviruses among different hosts has been frequently reported and resulted in numerous epidemics. Poxviruses have a complex linear double-strand DNA genome that encodes hundreds of proteins. Genes related to the host range of poxvirus are called host range genes (HRGs). This review briefly introduces the taxonomy, phylogeny and hosts of poxviruses, and then comprehensively summarizes the current knowledge about the cross-species transmission of poxviruses. In particular, the HRGs of poxvirus are described and their impacts on viral host range are discussed in depth. We hope that this review will provide a comprehensive perspective about the current progress of researches on cross-species transmission and HRG variation of poxviruses, serving as a valuable reference for academic studies and disease control in the future.

Boron Dopants in Red-Emitting B and N Co-Doped Carbon Quantum Dots Enable Targeted Imaging of Lysosomes.

Lysosomes are of great significance to cell growth, metabolism, and survival, as they independently maintain acidity and regulate various balances in cells. Therefore, it is essential to develop advanced probes for lysosome visualization and live tracking. Herein, a type of lysosome-targeting probe based on boron (B) and nitrogen (N) co-doped carbon quantum dots (B/N-CQDs) is presented, which exhibits red emission at 618 nm, high quantum yield (28%), and excellent fluorescence stability (97% at 1 h). These B/N-CQDs are prepared by a novel and green solid-state reaction and purified using a simple extraction process without additional chemical modifications. It is found that the boron dopants in the structure play a crucial role in the resultant lysosome-specific targeting property through borate esterification between boronic acid groups in the sample and diol structures in glycoproteins. This can be applied as a powerful tool for cell apoptosis, necrosis, and endosomal escape tracking. This work not only offers a new concept for targeted subcellular probe designs via chemical doping but also demonstrates the feasibility of these tools for analyzing complex cellular physiological activities.

Key mutations in the spike protein of SARS-CoV-2 affecting neutralization resistance and viral internalization.

To control the ongoing COVID-19 pandemic, a variety of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines have been developed. However, the rapid mutations of SARS-CoV-2 spike (S) protein may reduce the protective efficacy of the existing vaccines which is mainly determined by the level of neutralizing antibodies targeting S. In this study, we screened prevalent S mutations and constructed 124 pseudotyped lentiviral particles carrying these mutants. We challenged these pseudoviruses with sera vaccinated by Sinovac CoronaVac and ZF2001 vaccines, two popular vaccines designed for the initial strain of SARS-CoV-2, and then systematically assessed the susceptivity of these SARS-CoV-2 variants to the immune sera of vaccines. As a result, 14 S mutants (H146Y, V320I + S477N, V382L, K444R, L455F + S477N, L452M + F486L, F486L, Y508H, P521R, A626S, S477N + S698L, A701V, S477N + T778I, E1144Q) were found to be significantly resistant to neutralization, indicating reduced protective efficacy of the vaccines against these SARS-CoV-2 variants. In addition, F486L and Y508H significantly enhanced the utilization of human angiotensin-converting enzyme 2, suggesting a potentially elevated infectivity of these two mutants. In conclusion, our results show that some prevalent S mutations of SARS-CoV-2 reduced the protective efficacy of current vaccines and enhance the infectivity of the virus, indicating the necessity of vaccine renewal and providing direction for the development of new vaccines.