摘要： 新冠病毒的起源仍不清楚。了解新冠病毒如何、何时以及在何处从其天然宿主传播给人类对于预防未来由冠状病毒引发的疫情至关重要。 从与病原体无休止的战斗中吸取教训，结合目前已知的关于新冠病毒起源和中间宿主的研究数据，我们提出全球多个地点都有可能是新冠病毒的起源地。
摘要： In the comparison with SARS-CoV of 2003, SARS-CoV-2 is extremely well adapted to the human populations and its adaptive shift from the animal host to humans must have been even more extensive. By the blind watchmaker argument, such an adaptive shift can only happen prior to the onset of the current pandemic and with the aid of step-by-step selection. In this view, SARS-CoV-2 could not have possibly evolved in an animal market in a big city and even less likely in a laboratory. Discussions of the origin of SARS-CoV-2 need to factor in the long process of adaptive shift and some models have indeed advanced in that direction.
摘要：The ongoing outbreak of Coronavirus Disease 2019 (COVID-19) has become a global pandemic and crisis. SARS-coronavirus-2 (SARS-CoV-2), the causative pathogen of COVID-19, is a positive-sense single-stranded RNA virus belonging to the family Coronaviridae. For RNA viruses, virus-encoded RNA helicases have long been recognized to play pivotal roles during viral life cycles by facilitating the correct folding and replication of viral RNAs. Here, our studies show that SARS-CoV-2-encoded nonstructural protein 13 (nsp13) possesses the nucleoside triphosphate hydrolase (NTPase) and RNA helicase activities that can hydrolyze all types of NTPs and unwind RNA helices dependently of the presence of NTP, and further characterize the biochemical characteristics of these two enzymatic activities associated with SARS-CoV-2 nsp13. Moreover, we found that some bismuth salts could effectively inhibit both the NTPase and RNA helicase activities of SARS-CoV-2 nsp13 in a dose-dependent manner. Thus, our findings demonstrate the NTPase and helicase activities of SARS-CoV-2 nsp13, which may play an important role in SARS-CoV-2 replication and serve as a target for antivirals.
摘要： Frequent outbreaks of coronavirus make the development of an effective vaccine imperative. Recently, vaccines based on in-vitro transcribed messenger RNA (mRNA) have shown great potential. The streamlined manufacturing of mRNA molecules, combined with the superior flexibility in the antigen screening, greatly accelerates the development process. When using an mRNA platform to develop a vaccine, initial antigen choice plays a crucial role in determining the final efficacy and safety of the vaccine. Furthermore, mRNA sequences that encode antigens require extensive optimization to ensure highly efficient and sustained expression. Our ongoing efforts to develop an effective mRNA vaccine against 2019-nCoV place emphasis on the virus-like particles (VLPs) as the presenting antigen. At the same time, our second fast track uses mRNA to express the receptor-binding domain of the spike protein(S-RBD). After extensive optimization, an mRNA cocktail containing three genes is able to produce 2019-nCoV virus-like particles highly similar to the native 2019-nCoV. Meanwhile, an mRNA vaccine candidate expressing S-RBD is being tested in mice for its immunogenicity. We will next compare both the efficacy and the safety of the two mRNA vaccines based on S-RBD and VLPs, respectively.
摘要： 新型冠状病毒肺炎目前仍在武汉和中国其他地区持续。在目前的形势下，进一步了解新型冠状病毒（SARS-CoV-2）的病毒学和病毒与宿主的相互作用，对控制感染、开发有效的治疗方法具有重要意义。RNA干扰（RNA interference，RNAi）是一种进化上保守的真核生物抗病毒免疫机制，目前已发现许多病毒编码自身的RNA干扰抑制因子作为对抗措施。在这项研究中，我们发现SARS-CoV-2编码的核衣壳蛋白（N）有效地抑制了shRNAs或siRNAs触发的RNAi。此外，与许多由其他病毒编码的VSR类似，SARS-CoV-2的VSR在体外与人类细胞中与dsRNA相互作用，显示出双链RNA（dsRNA）结合活性。综上所述，我们的研究结果表明，SARS-CoV-2的N蛋白在人类细胞中表现出VSR活性，这可能是新型冠状病毒的一个关键免疫逃避因子。
摘要：Background. The outbreak of COVID-19 started in mid-December 2019 in Wuhan, Central China. Up to February 18, 2020, SARS-CoV-2 has infected more than 70,000 people in China, and another 25 countries across five continents. In this study, we used 93 complete genomes of SARS-CoV-2 from the GISAID EpiFluTM database to decode the evolution and human-to-human transmissions of SARS-CoV-2 in the recent two months. Methods. Alignment of coding-regions was conducted haplotype analyses using DnaSP. Substitution sites were analyzed in codon. Evolutionary analysis of haplotypes used NETWORK. Population size changes were estimated using both DnaSP and Arlequin. Expansion date of population size was calculated based on the expansion parameter tau (τ) using the formula t=τ/2u. Findings. Eight coding-regions have 120 substitution sites, including 79 non-synonymous and 40 synonymous substitutions. Forty-two non-synonymous substitutions changed the biochemical property of amino acids. No evident combination was found. Fifty-eight haplotypes were classified as five groups, and 31 haplotypes were found in samples from both China and other countries, respectively. The rooted network suggested H13 and H35 to be ancestral haplotypes, and H1 (and its descendent haplotypes including all samples from the Hua Nan market) was derived H3 haplotype. Population size of SARS-CoV-2 were estimated to have a recent expansion on 6 January 2020, and an early expansion on 8 December 2019. Interpretation. Genomic variations of SARS-CoV-2 are still low in comparisons with published genomes of SARS-CoV and MERS-CoV. Phyloepidemiologic analyses indicated the SARS-CoV-2 source at the Hua Nan market should be imported from other places. The crowded market boosted SARS-CoV-2 rapid circulations in the market and spread it to the whole city in early December 2019. Furthermore, phyloepidemiologic approaches have recovered specific direction of human-to-human transmissions, and the import sources of international infectious cases.
摘要：摘要：2019年12月，中国武汉报道了2019新型冠状病毒（2019 novel Coronavirus，2019-nCoV）引起的肺炎。基于基因组信息，我们前期研究结果显示2019-nCoV与SARS冠状病毒虽然同属于Beta冠状病毒B亚群（BB冠状病毒），但两种病毒差异很大，这一结果与两者临床症状差异一致。前期研究还发现了BB冠状病毒存在大量的可变翻译，并从分子水平揭示了BB冠状病毒变异快、多样性高的特点。本研究在国际上首次报道BB冠状病毒S蛋白上的一个重要突变，这个突变使2019-nCoV具有了一个可供Furin蛋白酶切的位点，是除鼠肝炎冠状病毒外所有的其它BB冠状病毒（包括SARS和SARS样（SARS-like）冠状病毒）所不具有的。这个突变有可能增强了2019-nCoV侵染细胞的效率，进而使其传播力显著大于SARS冠状病毒。由于这个突变，2019冠状病毒的包装机制也会不同于SARS等其它大部分Beta冠状病毒，而有可能与鼠肝炎冠状病毒、HIV、埃博拉病毒和一些禽流感病毒的包装机制相同。作为一个意外发现，一些禽流感病毒也可以通过突变获得Furin蛋白酶切位点。对这个重要突变的后续研究将为揭示2019-nCoV传播力强的原因，以及为药物、抗体和疫苗的开发等工作奠定基础。
摘要： 本研究的主要目的是检测硬蜱携带的病毒。作为一个意外发现，检测到一个235 bp的来自非洲猪瘟病毒基因组的特异性片段。随后的测序发现，蜱和羊都具有这个片段，特别是共有一个特异性突变C38T，是目前已发布的非洲猪瘟病毒基因组上对应片段都没有的。
摘要：Objective: Viral clearance of human HBV infection largely depends on the age of exposure, so a mouse model with age-dependent immune response and immune-tolerance for HBV infection is essential. Methods: HBVRag1 mice were generated by crossing Rag1-/- mice with HBV-Tg mice. The differences between adult and young HBVRag1 mice were detected after adoptive transfer of splenocytes. Immune tolerance was evaluated by quantitative hepatitis B core antibody (qAnti-HBc) assay, adoptive transfer, and modulation of gut microbiota with antibiotic. Results: After HBVRag1 mouse reconstitution, adult mice showed obvious HBV-dependent inflammation and hepatocytes damage, cleared HBsAg and generated HBsAb and HBcAb, but young mice never developed ALT elevation, and only generated HBcAb with persistence of HBsAg. In addition, for adult mice, more hepatic CD8+T and B cells promoted clearance of HBsAg 30 days after lymphocytes transfer, and for young mice, higher levels of cytokines link to the persistence of viral antigens during initiation of immune response towards HBV. The level of qAnti-HBc increased significantly with the time of adoptive transfer in young mice, but decreased significantly in adult within our model. This mimics kinetic changes of human HBV infection regarding qAnti-HBc level. Also, the age-related tolerance in this model was different from which was in HBV-Tg mice, and can be regulated through modulation of gut microbiota. Meanwhile, GS-9620 can achieve inhibition of HBsAg, but HBV vaccine just clears limited HBsAg within the model. Conclusions: Here, we described a mouse model with age-dependent immune response and immune tolerance of HBV infection which could mimic chronic HBV infection in human. It will open a door for evaluating new therapeutic approaches before clinical trials.