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The newly identified Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has resulted in a global health emergency because of its rapid spread and high mortality. The molecular mechanism of interaction between host and viral genomic RNA is yet unclear. We demonstrate herein that SARS-CoV-2 genomic RNA, as well as the negative-sense RNA, is dynamically N 6 -methyladenosine (m 6 A)-modified in human and monkey cells. Combined RIP-seq and miCLIP analyses identified a total of 8 m 6 A sites at single-base resolution in the genome. Especially, epidemic strains with mutations at these identified m 6 A sites have emerged worldwide, and formed a unique cluster in the US as indicated by phylogenetic analysis. Further functional experiments showed that m 6 A methylation negatively regulates SARS-CoV-2 infection. SARS-CoV-2 infection also triggered a global increase in host m 6 A methylome, exhibiting altered localization and motifs of m 6 A methylation in mRNAs. Altogether, our results identify m 6 A as a dynamic epitranscriptomic mark mediating the virus–host interaction.

Antennae are often considered to be the nostrils of insects. Here, we sequenced the transcriptome of the pheromone gland-ovipositor complex of Helicoverpa assulta and discovered that an odorant receptor (OR) gene, HassOR31, had much higher expression in the ovipositor than in antennae or other tissues. To determine whether the ovipositor was involved in odorant detection, we co-expressed HassOR31 and its co-receptor, HassORco, in a Xenopus oocyte model system, and demonstrated that the OR was responsive to 12 plant odorants, especially Z-3-hexenyl butyrate. These odorants elicited electrophysiological responses of some sensilla in the ovipositor, and HassOR31 and HassORco were co-expressed within ovipositor sensilla. Two oviposition preference experiments showed that female moths lacking antennae still preferentially selected oviposition sites containing plant volatiles. We suggest that the expression of HassOR31 in the ovipositor of H. assulta helps females to determine precise egg-laying sites in host plants. When most insects reproduce they lay eggs that hatch into juveniles known as larvae. To provide good sources of food for the larvae, the adult insects have to carefully select where to lay the eggs. Host plants produce specific sets of chemicals known as odorants that the adult insects are able to smell using proteins called odorant receptors. It is generally thought that odorant receptors in the antennae on the head are responsible for guiding adult insects to good egg-laying sites. However, recent studies have reported that odorant receptors are also present in the egg-laying organs of several different species of moth. It remains unclear what role these odorant receptors may play in egg-laying. The oriental tobacco budworm (Helicoverpa assulta) is considered a serious pest in agriculture. The adult moths lay their eggs on a narrow range of plants in the nightshade family including tobacco and hot pepper. Li et al. have now investigated the odorant receptors of H. assulta and found that one gene for an odorant receptor called HassOR31 was expressed much more in the egg-laying organs of the moths than in the antennae. Further experiments showed that this receptor was tuned to respond to 12 odorants that also stimulated responses in the egg-laying organ of H. assulta. Together these findings suggest that this odorant receptor in the egg-laying organ helps the moths find suitable host plants to lay their eggs on. The work of Li et al. may help us understand how H. assulta evolved to lay its eggs on specific members of the nightshade family and lead to new methods of controlling this pest. An insect’s sense of smell guides many other behaviors including finding food, mates and avoiding enemies. Therefore, these findings may inspire researchers to investigate whether odorant receptors in the antennae or other organs guide these behaviors.

There is an urgent need for animal models to study SARS-CoV-2 pathogenicity. Here, we generate and characterize a novel mouse-adapted SARS-CoV-2 strain, MASCp36, that causes severe respiratory symptoms, and mortality. Our model exhibits age- and gender-related mortality akin to severe COVID-19. Deep sequencing identified three amino acid substitutions, N501Y, Q493H, and K417N, at the receptor binding domain (RBD) of MASCp36, during in vivo passaging. All three RBD mutations significantly enhance binding affinity to its endogenous receptor, ACE2. Cryo-electron microscopy analysis of human ACE2 (hACE2), or mouse ACE2 (mACE2), in complex with the RBD of MASCp36, at 3.1 to 3.7 Å resolution, reveals the molecular basis for the receptor-binding switch. N501Y and Q493H enhance the binding affinity to hACE2, whereas triple mutations at N501Y/Q493H/K417N decrease affinity and reduce infectivity of MASCp36. Our study provides a platform for studying SARS-CoV-2 pathogenesis, and unveils the molecular mechanism for its rapid adaptation and evolution. In this study, Qin et al. present a murine-adapted SARS-CoV-2 strain, MASCp36, as a model for studying the pathogenicity, evolution and adaptation of the virus to human and animal hosts.

Photocatalytic four-component reaction is an efficient and environmentally friendly synthetic strategy known for its step economy and operational simplicity, enabling the preparation of diverse organic products. However, its application in synthesizing covalent organic frameworks (COFs) remains unexplored. Here, we report the rational synthesis of a class of functionalized COFs with high crystallinity and permanent porosity via the photocatalytic four-component reaction. This strategy not only addresses the long-standing challenge of harsh reaction conditions in conventional COFs synthesis methods, but also enables the integration of four different types of monomers in a one-pot process to create structurally diverse COFs. Furthermore, the resulting Cp-tBu-N 3 -COF can function as an efficient photocatalyst for the visible-light-driven synthesis of benzimidazoles. This work provides a promising strategy to access COFs in a mild and sustainable way. Photocatalytic four-component reaction is a green and efficient synthetic strategy. Here, the authors report a series of covalent organic frameworks via the photocatalytic four-component reaction, which are used for photocatalysis.

Dengue virus (DENV) poses a major global health threat, affecting an estimated 100 to 400 million people annually. The infection and pathogenesis remain incompletely understood, and no antiviral drug is currently approved for DENV treatment. Here, we develop a human pluripotent stem cell (hPSC)-derived liver organoid (hPLO) model to characterize DENV infection and screen for antivirals. The hPLOs, containing various liver cell types, are highly susceptible to DENV-2 infection, resulting in severe cell death and morphological changes that mimic the pathology observed in severe dengue cases. Single-cell RNA sequencing (scRNA-seq) of DENV-2 infected hPLOs reveals that proliferating hepatocyte-like cells are the primary target cells of DENV-2, with significant mitochondrial damage and alterations in cell-type composition. Further drug screening in hPLOs identifies oxyresveratrol (Oresveratrol, ORES) and omaveloxolone (RTA 408) as potent anti-DENV candidates. These compounds enhance resistance to DENV-2 infection by activating the NRF2 pathway, reducing oxidative stress, and preserving mitochondrial function. The efficacy of ORES and RTA 408 is further validated in the established AG6 mouse model. Our study not only establishes hPLOs as a valuable platform for studying DENV infection and pathogenesis, but also highlights the vital role of NRF2-mediated mitochondrial function for antiviral development. Here, Li et al. develop a human liver organoid model to elucidate Dengue virus infection dynamics and identify oxyresveratrol as a potential antiviral candidate, highlighting the NRF2 pathway’s crucial role in mitigating mitochondrial damage and enhancing cellular resistance.

Increasing evidence shows the African lineage Zika virus (ZIKV) displays a more severe neurovirulence compared to the Asian ZIKV. However, viral determinants and the underlying mechanisms of enhanced virulence phenotype remain largely unknown. Herein, we identify a panel of amino acid substitutions that are unique to the African lineage of ZIKVs compared to the Asian lineage by phylogenetic analysis and sequence alignment. We then utilize reverse genetic technology to generate recombinant ZIKVs incorporating these lineage-specific substitutions based on an infectious cDNA clone of Asian ZIKV. Through in vitro characterization, we discover a mutant virus with a lysine to arginine substitution at position 101 of capsid (C) protein (termed K101R) displays a larger plaque phenotype, and replicates more efficiently in various cell lines. Moreover, K101R replicates more efficiently in mouse brains and induces stronger inflammatory responses than the wild type (WT) virus in neonatal mice. Finally, a combined analysis reveals the K101R substitution promotes the production of mature C protein without affecting its binding to viral RNA. Our study identifies the role of K101R substitution in the C protein in contributing to the enhanced virulent phenotype of the African lineage ZIKV, which expands our understanding of the complexity of ZIKV proteins. The neurovirulence determinants of Zika virus remain not fully established. Song et al identified a single K101R substitution in the capsid protein that contributes to the lineage-specific virulence phenotypes.

The recent worldwide outbreaks of mpox prioritize the development of a safe and effective mRNA vaccine. The contemporary mpox virus (MPXV) exhibits changing virological and epidemiological features, notably affecting populations already vulnerable to human immunodeficiency virus (HIV). Herein, we profile the immunogenicity of AR-MPXV5, a penta-component mRNA vaccine targeting five specific proteins (M1R, E8L, A29L, A35R, and B6R) from the representative contemporary MPXV clade II strain, in both naive and simian immunodeficiency virus (SIV)-infected nonhuman primates. Immunization with two doses of AR-MPXV5 to cynomolgus macaques effectively elicits antibody responses and cellular responses. Importantly, based on the challenge model with a contemporary MPXV clade II strain, AR-MPXV5 demonstrates effective efficacy in preventing skin lesions, eliminating viremia and reducing viral loads in multiple tissues after challenge in naive male animals. More importantly, AR-MPXV5 is well-tolerated in stable chronic SIV-infected rhesus monkeys, while eliciting comparable MPXV-specific humoral and cellular responses in both naive and SIV-infected monkeys. Together, these results support further clinical development of the AR-MPXV5 vaccine. Here, the authors report immunogenicity and safety of AR-MPXV5, a penta-component mRNA vaccine, in naive and simian immunodeficiency virus infected nonhuman primates (NHPs), and demonstrate protection in naïve male NHPs after immunization with two doses of AR-MPXV5.

Human RNA binding protein Musashi-1 (MSI1) plays a critical role in neural progenitor cells (NPCs) by binding to various host RNA transcripts. The canonical MSI1 binding site (MBS), A/GU (1-3) AG single-strand motif, is present in many RNA virus genomes, but only Zika virus (ZIKV) genome has been demonstrated to bind MSI1. Herein, we identified the AUAG motif and the AGAA tetraloop in the Xrn1-resistant RNA 2 (xrRNA2) as the canonical and non-canonical MBS, respectively, and both are crucial for ZIKV neurotropism. More importantly, the unique AGNN-type tetraloop is evolutionally conserved, and distinguishes ZIKV from other known viruses with putative MBSs. Integrated structural analysis showed that MSI1 binds to the AUAG motif and AGAA tetraloop of ZIKV in a bipartite fashion. Thus, our results not only identified an unusual viral RNA structure responsible for MSI recognition, but also revealed a role for the highly structured xrRNA in controlling viral neurotropism. Human RNA binding protein Musashi-1 binds various host transcripts as well as Zika virus RNA in neural progenitor cells. Here, Chen et al . characterise the interactions between Musashi-1 and its binding site using a combination of molecular and biophysical methods to shed light on its role in viral neurotropism.

As societal perceptions of pet ownership shift, an increasing number of individuals are choosing to keep pets, leading to various challenges. In Taiwan, the growing population of stray dogs and cats is largely attributed to insufficient education and inadequate management practices among pet owners, posing public health and safety concerns. This issue primarily stems from a lack of understanding regarding proper pet care. In response, awareness of animal protection and life education has been gaining traction, drawing attention to these concerns. To address this, this study introduces an augmented reality (AR) pet care teaching system aimed at enhancing pet care knowledge through smartphones or tablets. Utilizing interactive AR technology, students are able to meet learning objectives related to pet care and foundational knowledge. This study adopts a quasi-experimental design and incorporates questionnaire surveys involving 61 college students and 8 teachers. The findings indicate that while both AR and traditional teaching methods are effective, the AR group exhibited superior learning outcomes. Furthermore, teacher feedback emphasized that the AR system fosters greater student engagement and significantly improves learning effectiveness.

SARS-CoV-2 infection causes a wide spectrum of clinical manifestations in humans, and olfactory dysfunction is one of the most predictive and common symptoms in COVID-19 patients. However, the underlying mechanism by which SARS-CoV-2 infection leads to olfactory disorders remains elusive. Herein, we demonstrate that intranasal inoculation with SARS-CoV-2 induces robust viral replication in the olfactory epithelium (OE), not the olfactory bulb (OB), resulting in transient olfactory dysfunction in humanized ACE2 (hACE2) mice. The sustentacular cells and Bowman’s gland cells in the OE were identified as the major target cells of SARS-CoV-2 before invasion into olfactory sensory neurons (OSNs). Remarkably, SARS-CoV-2 infection triggers massive cell death and immune cell infiltration and directly impairs the uniformity of the OE structure. Combined transcriptomic and quantitative proteomic analyses revealed the induction of antiviral and inflammatory responses, as well as the downregulation of olfactory receptor (OR) genes in the OE from the infected animals. Overall, our mouse model recapitulates olfactory dysfunction in COVID-19 patients and provides critical clues for understanding the physiological basis for extrapulmonary manifestations of COVID-19.