The 2002–3 pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV) was one of the most significant public health events in recent history1. An ongoing outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV)2 suggests that this group of viruses remains a major threat and that their distribution is wider than previously recognized. Although bats have been suggested as the natural reservoirs of both viruses3–5, attempts to isolate the progenitor virus of SARS-CoV from bats have been unsuccessful. Diverse SARS-like coronaviruses (SL-CoVs) have now been reported from bats in China, Europe and Africa5–8, but none are considered a direct progenitor of SARS-CoV because of their phylogenetic disparity from this virus and the inability of their spike proteins (S) to use the SARS-CoV cellular receptor molecule, the human angiotensin converting enzyme II (ACE2)9,10. Here, we report whole genome sequences of two novel bat CoVs from Chinese horseshoe bats (Family: Rhinolophidae) in Yunnan, China; RsSHC014 and Rs3367. These viruses are far more closely related to SARS-CoV than any previously identified bat CoVs, particularly in the receptor binding domain (RDB) of the S protein. Most importantly, we report the first recorded isolation of a live SL-CoV (bat SL-CoV-WIV1) from bat fecal samples in Vero E6 cells, which has typical coronavirus morphology, 99.9% sequence identity to Rs3367 and uses the ACE2s from human, civet and Chinese horseshoe bat for cell entry. Preliminary in vitro testing indicates that WIV1 also has a broad species tropism. Our results provide the strongest evidence to date that Chinese horseshoe bats are natural reservoirs of SARS-CoV, and that intermediate hosts may not be necessary for direct human infection by some bat SL-CoVs. They also highlight the importance of pathogen discovery programs targeting high-risk wildlife groups in emerging disease hotspots as a strategy for pandemic preparedness.

Bats are presumed reservoirs of diverse coronaviruses (CoVs) including progenitors of Severe Acute Respiratory Syndrome (SARS)-CoV and SARS-CoV-2, the causative agent of COVID-19. However, the evolution and diversification of these coronaviruses remains poorly understood. Here we use a Bayesian statistical framework and a large sequence data set from bat-CoVs (including 630 novel CoV sequences) in China to study their macroevolution, cross-species transmission and dispersal. We find that host-switching occurs more frequently and across more distantly related host taxa in alpha-than beta-CoVs, and is more highly constrained by phylogenetic distance for beta-CoVs. We show that inter-family and-genus switching is most common in Rhinolophidae and the genus Rhinolophus. Our analyses identify the host taxa and geographic regions that define hotspots of CoV evolutionary diversity in China that could help target bat-CoV discovery for proactive zoonotic disease surveillance. Finally, we present a phylogenetic analysis suggesting a likely origin for SARS-CoV-2 in Rhinolophus spp. bats.

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BackgroundRodents represent around 43% of all mammalian species, are widely distributed, and are the natural reservoirs of a diverse group of zoonotic viruses, including hantaviruses, Lassa viruses, and tick-borne encephalitis viruses. Thus, analyzing the viral diversity harbored by rodents could assist efforts to predict and reduce the risk of future emergence of zoonotic viral diseases.ResultsWe used next-generation sequencing metagenomic analysis to survey for a range of mammalian viral families in rodents and other small animals of the orders Rodentia, Lagomorpha, and Soricomorpha in China. We sampled 3,055 small animals from 20 provinces and then outlined the spectra of mammalian viruses within these individuals and the basic ecological and genetic characteristics of novel rodent and shrew viruses among the viral spectra. Further analysis revealed that host taxonomy plays a primary role and geographical location plays a secondary role in determining viral diversity. Many viruses were reported for the first time with distinct evolutionary lineages, and viruses related to known human or animal pathogens were identified. Phylogram comparison between viruses and hosts indicated that host shifts commonly happened in many different species during viral evolutionary history.ConclusionsThese results expand our understanding of the viromes of rodents and insectivores in China and suggest that there is high diversity of viruses awaiting discovery in these species in Asia. These findings, combined with our previous bat virome data, greatly increase our knowledge of the viral community in wildlife in a densely populated country in an emerging disease hotspot.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0554-9) contains supplementary material, which is available to authorized users.

CdS-reduced graphene oxide (RGO) composites are successfully synthesized via the microwave-assisted reduction of graphite oxide in a CdS precursor solution using a microwave synthesis system. The photocatalytic performances of CdS-RGO composites in the reduction of Cr(VI) are investigated. The results show that CdS-RGO composites exhibit enhanced photocatalytic performance for the reduction of Cr(VI) with a maximum removal rate of 92% under visible light irradiation as compared with pure CdS (79%) due to the increased light absorption intensity and the reduction of electron-hole pair recombination in CdS with the introduction of RGO.

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Large noncoding RNA HOTAIR, transcribed from the antisense strand of HOXC12, interacts with Polycomb Repressive Complex 2 (PRC2) in the regulation of gene activities. Recent work suggests that it may have effects on breast cancer progression and survival. We evaluated HOTAIR expression and the methylation status of its downstream intergenic CpG island in primary breast cancers, and examined associations of these factors with clinical and pathologic features and patient survival. HOTAIR expression and DNA methylation were analyzed in tissue from 348 primary breast cancers with quantitative RT-PCR and methylation-specific PCR, respectively. HOTAIR expression and methylation varied widely in the tissues. A positive correlation was found between DNA methylation and HOTAIR expression. Methylation was associated with unfavorable disease characteristics, whereas no significant associations were found between HOTAIR expression and clinical or pathologic features. In multivariate, but not in univariate, Cox proportional hazard regression models, patients with high HOTAIR expression had lower risks of relapse and mortality than those with low HOTAIR expression. These findings suggest that the intergenic DNA methylation may have important biologic relevance in regulating HOTAIR expression, and that HOTAIR expression may not be an independent prognostic marker in breast cancer, but needs further validation in independent studies.

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