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Monkeypox (mpox) outbreak in 2022 has caused more than 91,000 cases, has spread to 115 countries, regions, and territories, and has thus attracted much attention. The stability of poxvirus particles in the environment is recognized as an important factor in determining their transmission. However, few studies have investigated the persistence of poxviruses on material surfaces under various environmental conditions, and their sensitivity to biocides. Here, we systematically measured the stability of vaccinia virus (VACV) under different environmental conditions and sensitivity to inactivation methods via plaque assay, quantitative real-time polymerase chain reaction (qPCR), and Gaussia luciferase (G-luciferase) reporter system. The results show that VACV is stable on the surface of stainless steel, glass, clothing, plastic, towel, A4 paper, and tissue and persists much longer at 4 °C and −20 °C, but is effectively inactivated by ultraviolet (UV) irradiation, heat treatment, and chemical reagents. Our study raises the awareness of long persistence of poxviruses in the environment and provides a simple solution to inactivate poxviruses using common disinfectants, which is expected to help the control and prevention of mpox virus and future poxvirus outbreaks.

Among persons born in China before 1980 and tested for vaccinia virus Tiantan strain (VVT), 28.7% (137/478) had neutralizing antibodies, 71.4% (25/35) had memory B-cell responses, and 65.7% (23/35) had memory T-cell responses to VVT. Because of cross-immunity between the viruses, these findings can help guide mpox vaccination strategies in China.

Summary: Mpox is caused by a zoonotic virus belonging to the Orthopoxvirus genus and the Poxviridae family. In this study, we develop a recombinase polymerase amplification (RPA)-coupled CRISPR-Cas12a detection assay for the mpox virus. We design and test a series of CRISPR-derived RNAs(crRNAs) targeting the conserved D6R and E9L genes for orthopoxvirus and the unique N3R and N4R genes for mpox viruses. D6R crRNA-1 exhibits the most robust activity in detecting orthopoxviruses, and N4R crRNA-2 is able to distinguish the mpox virus from other orthopoxviruses. The Cas12a/crRNA assay alone presents a detection limit of 108 copies of viral DNA, whereas coupling RPA increases the detection limit to 1–10 copies. The one-tube RPA-Cas12a assay can, therefore, detect viral DNA as low as 1 copy within 30 min and holds the promise of providing point-of-care detection for mpox viral infection. Motivation: The rise of mpox cases in many previously non-endemic countries in 2022 prompted the WHO to declare mpox as a public health emergency of international concern. Since it is difficult to detect mpox at the early stage of infection, a rapid and accurate diagnostic assay for the mpox virus is essential to control its spread and enable timely treatment. Here, we present an RPA-Cas12a ribonucleoprotein-based method for rapid and sensitive detection of mpox.

Serious harms of flash flood can be caused by heavy precipitation. Based on flash flood disasters, soil moisture information and the historical precipitation data, etc. from January 2013 to December 2016, the temporospatial distribution characteristics of precipitation and flash flood over China and in several typical regions (Yunnan Province, Guizhou Province, Sichuan Province and Chongqing Province) are preliminarily analyzed. The method of static critical precipitation of flash flood is developed by establishing the relationship between flash flood events and precipitation at different time-scales (1 h, 6 h, 12 h and 24 h) before each flash flood event. Combined with the characteristics of the relative soil moisture in different layers (10~50 cm) at different time period before disasters, the dynamic critical precipitation threshold is calculated as well. The dynamic critical precipitation threshold model of flash flood in national and regional domains is proposed in the paper. The results show that the models perform well, and the hit ratio of the dynamic model reaches 73%, which is better than the static model.

SERINC5 is a multi-span transmembrane protein that is incorporated into HIV-1 particles in producing cells and inhibits HIV-1 entry. Multiple retroviruses like HIV-1, equine infectious anemia virus and murine leukemia virus are subject to SERINC5 inhibition, while HIV-1 pseudotyped with envelope glycoproteins of vesicular stomatitis virus and Ebola virus are resistant to SERINC5. The antiviral spectrum and the underlying mechanisms of SERINC5 restriction are not completely understood. Here we show that SERINC5 inhibits influenza A virus infection by targeting virus-cell membrane fusion at an early step of infection. Further results show that different influenza hemagglutinin (HA) subtypes exhibit diverse sensitivities to SERINC5 restriction. Analysis of the amino acid sequences of influenza HA1 strains indicates that HA glycosylation sites correlate with the sensitivity of influenza HA to SERINC5, and the inhibitory effect of SERINC5 was lost when certain HA glycosylation sites were mutated. Our study not only expands the antiviral spectrum of SERINC5, but also reveals the role of viral envelope glycosylation in resisting SERINC5 restriction.

The membrane-associated RING-CH (MARCH) proteins are E3 ligases regulating stability of plasma membrane (PM) proteins. Here, Liu et al. show that MARCH8 suppresses Influenza A virus infection in vitro and in vivo through redirecting M2 protein from the PM to lysosomes for degradation.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines provide essential tools for the control of the COVID-19 pandemic. A number of technologies have been employed to develop SARS-CoV-2 vaccines, including the inactivated SARS-CoV-2 particles, mRNA to express viral spike protein, recombinant spike proteins, and viral vectors. Here, we report the use of the vaccinia virus Tiantan strain as a vector to express the SARS-CoV-2 spike protein. When it was used to inoculate mice, robust SARS-CoV-2 spike protein-specific antibody response and T-cell response were detected. Sera from the vaccinated mice showed strong neutralizing activity against the ancestral Wuhan SARS-CoV-2, the variants of concern (VOCs) B.1.351, B.1.617.2, and the emerging B.1.1.529 (omicron). This finding supports the possibility of developing a new type of SARS-CoV-2 vaccine using the vaccinia virus vector.

Long interspersed element type 1 (LINE-1, also L1 for short) is the only autonomously transposable element in the human genome. Its insertion into a new genomic site may disrupt the function of genes, potentially causing genetic diseases. Cells have thus evolved a battery of mechanisms to tightly control LINE-1 activity. Here, we report that a cellular antiviral protein, myxovirus resistance protein B (MxB), restricts the mobilization of LINE-1. This function of MxB requires the nuclear localization signal located at its N-terminus, its GTPase activity and its ability to form oligomers. We further found that MxB associates with LINE-1 protein ORF1p and promotes sequestration of ORF1p to G3BP1-containing cytoplasmic granules. Since knockdown of stress granule marker proteins G3BP1 or TIA1 abolishes MxB inhibition of LINE-1, we conclude that MxB engages stress granule components to effectively sequester LINE-1 proteins within the cytoplasmic granules, thus hindering LINE-1 from accessing the nucleus to complete retrotransposition. Thus, MxB protein provides one mechanism for cells to control the mobility of retroelements. Author summary Retrotransposons occupy more than 40% of human genome, and have co-evolved with humans for millions of years. Long interspersed element type 1 (LINE-1, or L1) is the only retrotransposon that is able to jump to a new locus. LINE-1 retrotransposition causes genome instability, and is associated with genetic diseases including autoimmune diseases and cancer. To suppress this genome toxicity caused by LINE-1, humans have developed multi-layered mechanisms to control LINE-1 activity. MxB has been previously shown to inhibit LINE-1 mobility, thus contributing to host restriction of LINE-1. Here, we further demonstrate that MxB effectively restricts LINE-1 retrotransposition by sequestering LINE-1 ribonucleoprotein (RNP) within the cytoplasmic stress granules, thus guards genome stability. Hence our data attribute the restriction function of MxB to sequestering LINE-1 RNP to stress granules.

Long interspersed element type 1 (LINE-1, also L1 for short) is the only autonomously transposable element in the human genome. Its insertion into a new genomic site may disrupt the function of genes, potentially causing genetic diseases. Cells have thus evolved a battery of mechanisms to tightly control LINE-1 activity. Here, we report that a cellular antiviral protein, myxovirus resistance protein B (MxB), restricts the mobilization of LINE-1. This function of MxB requires the nuclear localization signal located at its N-terminus, its GTPase activity and its ability to form oligomers. We further found that MxB associates with LINE-1 protein ORF1p and promotes sequestration of ORF1p to G3BP1-containing cytoplasmic granules. Since knockdown of stress granule marker proteins G3BP1 or TIA1 abolishes MxB inhibition of LINE-1, we conclude that MxB engages stress granule components to effectively sequester LINE-1 proteins within the cytoplasmic granules, thus hindering LINE-1 from accessing the nucleus to complete retrotransposition. Thus, MxB protein provides one mechanism for cells to control the mobility of retroelements.

CRISPR-Cas provides bacteria and archaea with immunity against invading phages and foreign plasmid DNA and has been successfully adapted for gene editing in a variety of species. The class 2 type VI CRISPR-Cas effector Cas13a targets and cleaves RNA, providing protection against RNA phages. Here we report the repurposing of CRISPR-Cas13a to inhibit human immunodeficiency virus type 1 (HIV-1) infection through targeting HIV-1 RNA and diminishing viral gene expression. We observed strong inhibition of HIV-1 infection by CRISPR-Cas13a in human cells. We showed that CRISPR-Cas13a not only diminishes the level of newly synthesized viral RNA, either from the transfected plasmid DNA or from the viral DNA, which is integrated into cellular DNA, but it also targets and destroys the viral RNA that enters cells within viral capsid, leading to strong inhibition of HIV-1 infection. Together, our results suggest that CRISPR-Cas13a provides a potential novel tool to treat viral diseases in humans.

SARS-CoV-2 has become a global threat to public health. Infected individuals can be asymptomatic or develop mild to severe symptoms, including pneumonia, respiratory distress, and death. This wide spectrum of clinical presentations of SARS-CoV-2 infection is believed in part due to the polymorphisms of key genetic factors in the population. In this study, we report that the interferon-induced antiviral factor IFITM3 inhibits SARS-CoV-2 infection by preventing SARS-CoV-2 spike-protein-mediated virus entry and cell-to-cell fusion. Analysis of a Chinese COVID-19 patient cohort demonstrates that the rs12252 CC genotype of IFITM3 is associated with SARS-CoV-2 infection risk in the studied cohort. These data suggest that individuals carrying the rs12252 C allele in the IFITM3 gene may be vulnerable to SARS-CoV-2 infection and thus may benefit from early medical intervention.

Gynostemma pentaphyllum (GP), known as “southern ginseng”, can reduce the blood pressure and blood lipid levels. In this study, 300 layer chicks of one day old were divided randomly into three groups (control group (base diet), high addition group (base diet with 1% GP), and low addition group (base diet with 0.5% GP)). After 29 weeks, the growth performance, egg quality, and serum index were determined. Additionally, liver mRNA was identified using RNA-seq to investigate the molecular mechanisms. The results indicated that the serum total cholesterol and triglycerides decreased significantly in the GP addition group. The addition of GP increased the egg weight, Haugh unit and redness (a*) of the egg yolk color, and reduced the yolk cholesterol concentration. Moreover, 95 differentially expressed genes (DEGs) were screened between the control and GP addition group. GO and the KEGG analysis showed that the PPAR pathway was significantly enriched. Five fatty acid metabolism-related genes (FABP3, CYP7A1, ANKRD22, SCD1, and PCK1) were validated by qRT-PCR analysis, which confirmed the tendency of the expression. These DEGs in the PPAR pathway may be the key factors of GP affecting fatty acid metabolism. These results may provide a theoretical basis for further research and new insights into GP as a feed additive.

The SAM domain and HD domain containing protein 1 (SAMHD1) inhibits retroviruses, DNA viruses and long interspersed element 1 (LINE-1). Given that in dividing cells, SAMHD1 loses its antiviral function yet still potently restricts LINE-1, we propose that, instead of blocking viral DNA synthesis by virtue of its dNTP triphosphohydrolase activity, SAMHD1 may exploit a different mechanism to control LINE-1. Here, we report a new activity of SAMHD1 in promoting cellular stress granule assembly, which correlates with increased phosphorylation of eIF2α and diminished eIF4A/eIF4G interaction. This function of SAMHD1 enhances sequestration of LINE-1 RNP in stress granules and consequent blockade to LINE-1 retrotransposition. In support of this new mechanism of action, depletion of stress granule marker proteins G3BP1 or TIA1 abrogates stress granule formation and overcomes SAMHD1 inhibition of LINE-1. Together, these data reveal a new mechanism for SAMHD1 to control LINE-1 by activating cellular stress granule pathway.