The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical in...The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical industry.Here,we precisely constructed carbon nitride supported Pd-based catalysts by a simple impregnation-reduction method.By changing the reduction temperature,catalysts with different oxidation state could be precisely constructed.Moreover,the important correlation between the ratio of Pd^(0)/Pd^(2+)and catalytic activity is revealed during the selective hydrogenation of HMF.The Pd/g—C_(3)N_(4)—300 catalyst with a Pd^(0)/Pd^(2+)ratio of 3/2 showed the highest catalytic activity,which could get 96.9%5-hydroxymethylfurfural conversion and 90.3%2,5-dihydroxymethylfuran selectivity.Further density functional theory calculation revealed that the synergistic effect between Pd0and Pd2+in Pd/g—C_(3)N_(4)—300 system could boost the adsorption of the substrate and the dissociation of hydrogen.In this work,we highlight the important correlation between metal oxidation state and catalytic activity,which provides valuable insights for the rational design of precious metal catalysts for hydrogenation reactions.展开更多
Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic ac...Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.展开更多
Biodiversity is the basis for ecosystem goods and services that provide for human survival and prosperity. With a rapidly increasing human population and its demands for natural resources, landscapes are being fragmen...Biodiversity is the basis for ecosystem goods and services that provide for human survival and prosperity. With a rapidly increasing human population and its demands for natural resources, landscapes are being fragmented, habitats are being destroyed, and biodiversity is declining. How can biodiversity be effec- tively conserved in the face of increasing human pressures? In this paper, I review changing perspectives on biodiversity conservation, and discuss their relevance to the practice of biodiversity conservation. The major points include: The notion of balance of nature is a myth rather than a scientific concept; the theory of island biogeography is useful heuristically but flawed practically; the SLOSS debate is intriguing in theory but ir- relevant in reality; the concept of minimum viable population and population viability analysis are useful, but technically inefficient and conceptually inadequate; metapopulation theory is mathematically elegant but ecologically oversimplistic; and integrative perspectives and approaches for biodiversity conservation are needed that incorporate insights from landscape ecology and sustainability science. I further discuss some key principles for regional conservation planning, and argue that the long-term success of biodiversity con- servation in any region will ultimately depend on the economic and social sustainability of that region. Both research and practice in biodiversity conservation, therefore, need to adopt a broader perspective of sustain- ability.展开更多
The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakeni...The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength,meanwhile,its effects on coal deformation are quantitatively evaluated.The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure.Compared with non-gas-saturated coals,the maximum weakening ratios of adsorbed gas to coal strength are 10.58%,18.12%,8.55%and 14.65%under the conditions of confining stress CS=3 MPa and gas pressure GP=1 MPa,CS=3 MPa and GP=2 MPa,CS=4 MPa and GP=1 MPa,and CS=4 MPa and GP=2 MPa,respectively.Furthermore,the maximum weakening ratios of free gas to coal strength are 18.27%,36.54%,14.79%and 29.58%,respectively,under above four conditions.The maximum coal bulk strain decreases as particle sizes of coal powders increase,and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm.Under the same conditions,the coal bulk strain increases with increasing gas pressure,revealing that coal deformation properties can be enhanced by gas.展开更多
Plants and viruses coexist in the natural ecosystem for extended periods of time,interacting with each other and even coevolving,maintaining a dynamic balance between plant disease resistance and virus pathogenicity.D...Plants and viruses coexist in the natural ecosystem for extended periods of time,interacting with each other and even coevolving,maintaining a dynamic balance between plant disease resistance and virus pathogenicity.During virus–host interactions,plants often exhibit abnormal growth and development.However,plants do not passively withstand virus attacks but have evolved sophisticated and effective defense mechanisms to resist,limit,or undermine virus infections.It is widely believed that the initial stage of infection features the most intense interactions between the virus and the host and the greatest variety of activated signal transduction pathways.This review describes the most recent findings in rice antiviral research and discusses a variety of rice antiviral molecular mechanisms,including those based on R genes and recessive resistance,RNA silencing,phytohormone signaling,autophagy and WUSmediated antiviral immunity.Finally,we discuss the challenges and future prospects of breeding rice for enhanced virus resistance.展开更多
A quantitative real time reverse-transcription polymerase chain reaction （qRT-PCR） assay with specific primers recommended by the World Health Organization （WHO） has been widely used successfully for detection and...A quantitative real time reverse-transcription polymerase chain reaction （qRT-PCR） assay with specific primers recommended by the World Health Organization （WHO） has been widely used successfully for detection and monitoring of the pandemic H1N1/2009 influenza A virus. In this study, we report the design and characterization of a novel set of primers to be used in a qRT-PCR assay for detecting the pandemic H1N1/2009 virus. The newly designed primers target three regions that are highly conserved among the hemagglutinin （HA） genes of the pandemic HlN1/2009 viruses and are different from those targeted by the WHO-recommended primers. The qRT-PCR assays with the newly designed primers are highly specific, and as specific as the WHO-recommended primers for detecting pandemic H1N1/2009 viruses and other influenza viruses including influenza B viruses and influenza A viruses of human, swine, and raccoon dog origin. Furthermore, the qRT-PCR assays with the newly designed primers appeared to be at least 10-fold more sensitive than those with the WHO-recommended primers as the detection limits of the assays with our primers and the WHO-recommended primers were 2.5 and 25 copies of target RNA per reaction, respectively. When tested with 83 clinical samples, 32 were detected to be positive using the qRT-PCR assays with our designed primers, while only 25 were positive by the assays with the WHO-recommended primers. These results suggest that the qRT-PCR system with the newly designed primers represent a highly sensitive assay for diagnosis of the pandemic HIN1/2009 virus infection.展开更多
Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design...Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design,which inevitably requires holistic analysis and limits parallel processing.Here,we developed a digital organ-on-a-chip by combining a microwell array with cellular microspheres,which significantly increased the parallelism over traditional organ-on-a-chip for drug development.Up to 127 uniform liver cancer microspheres in this digital organ-on-a-chip format served as individual analytical units,allowing for analysis with high consistency and quick response.Our platform displayed evident anti-cancer efficacy at a concentration of 10μM for sorafenib,and had greater alignment than the“single pot”organ-on-a-chip with a previous in vivo study.In addition,this digital organ-on-a-chip demonstrated the treatment efficacy of natural killer cell-derived extracellular vesicles for liver cancer at 50μg/mL.The successful development of this digital organ-on-a-chip platform provides high-parallelism and a low-variability analytical tool for toxicity assessment and the exploration of new anticancer modalities,thereby accelerating the joint endeavor to combat cancer.展开更多
The global climate has changed substantially over the last 100 years,and associated changes in species distribution limits have occurred in recent decades.Climate change presents a challenge for biodiversity conservat...The global climate has changed substantially over the last 100 years,and associated changes in species distribution limits have occurred in recent decades.Climate change presents a challenge for biodiversity conservation on a global scale.The ability to detect changes in species distributions and attribute them to past climate change is crucial for the accurate prediction of future species distributions and for biodiversity conservation.This study proposes a technique for the quantitative detection of species distribution changes and their attribution to past climate change.An attribution value was defined to describe the extent to which the distributional changes for observed species could be attributed to climate change.The calculation thereof involved the following steps:(1)construction of a time series of observed species distributions and climatic factors,(2)estimation of the correlations between changes in species distributions and climatic factors,(3)prediction of changes in species distributions as driven by climatic factors,(4)estimation of the consistency between observed and predicted changes in species distributions,and(5)estimation of the attribution value.Furthermore,using nine snake species found in China as examples,we demonstrated in detail the practical application of this technique.This technique can be used to identify,based on global species distribution and climate data,the effects of climate change on species distributions over the past years on a global scale.展开更多
Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer...Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer japonica rice lines along with their parents. Two genetic models and their corresponding statistical methods for quantitative traits of triploid seeds in cereal crops were used for the analysis. The first was the unconditional genetic model, which refers to the analysis of cumulative measurements (from flowering to a specific time) along the developmental stages, while the second was the conditional genetic model, which relates to analysis from one developmental stage to another stage (t - 1→t). The results showed that leucine content of indica-japonica hybrid rice was controlled by the expression of triploid endosperm effect (endosperm additive effect and endosperm dominant effect), cytoplasm effect, diploid maternal plant effect (maternal additive effect and maternal dominant effect) and their environmental interaction effects. Of these effects, endosperm dominant effect and maternal dominant effect were more important at the earlier stages, while endosperm additive effect and maternal additive effect were more important at the later stages of rice grain development under both unconditional and conditional genetic analyses. Due to the high heritabilities, which came from endosperm, maternal and cytoplasm effects for leucine content at different developmental stages, selection for leucine content of indica-japonica hybrid rice would be more efficient at early generations in breeding programs.展开更多
Plant viruses are a group of intracellular pathogens that persistently threaten global food security.Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years,including bas...Plant viruses are a group of intracellular pathogens that persistently threaten global food security.Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years,including basic research and technologies for preventing and controlling plant viral diseases.Here,we review these milestones and advances,including the identification of new crop-infecting viruses,dissection of pathogenic mechanisms of multiple viruses,examination of multilayered interactions among viruses,their host plants,and virus-transmitting arthropod vectors,and in-depth interrogation of plantencoded resistance and susceptibility determinants.Notably,various plant virus-based vectors have also been successfully developed for gene function studies and target gene expression in plants.We also recommend future plant virology studies in China.展开更多
Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to im...Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.展开更多
Viral infection in respiratory tract usually leads to cell death,impairing respiratory function to cause severe disease.However,the diversity of clinical manifestations of SARS-CoV-2 infection increases the complexity...Viral infection in respiratory tract usually leads to cell death,impairing respiratory function to cause severe disease.However,the diversity of clinical manifestations of SARS-CoV-2 infection increases the complexity and difficulty of viral infection prevention,and especially the high-frequency asymptomatic infection increases the risk of virus transmission.Studying how SARS-CoV-2 affects apoptotic pathway may help to understand the pathological process of its infection.Here,we uncovered SARS-CoV-2 imployed a distinct anti-apoptotic mechanism via its N protein.We found SARS-CoV-2 virus-like particles(trVLP)suppressed cell apoptosis,but the trVLP lacking N protein didn’t.Further study verified that N protein repressed cell apoptosis in cultured cells,human lung organoids and mice.Mechanistically,N protein specifically interacted with anti-apoptotic protein MCL-1,and recruited a deubiquitinating enzyme USP15 to remove the K63-linked ubiquitination of MCL-1,which stabilized this protein and promoted it to hijack Bak in mitochondria.Importantly,N protein promoted the replications of IAV,DENV and ZIKV,and exacerbated death of IAV-infected mice,all of which could be blocked by a MCL-1 specific inhibitor,S63845.Altogether,we identifed a distinct anti-apoptotic function of the N protein,through which it promoted viral replication.These may explain how SARS-CoV-2 effectively replicates in asymptomatic individuals without cuasing respiratory dysfunction,and indicate a risk of enhanced coinfection with other viruses.We anticipate that abrogating the N/MCL-1-dominated apoptosis repression is conducive to the treatments of SARS-CoV-2 infection as well as coinfections with other viruses.展开更多
The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work is supported by the US Nati...The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work is supported by the US National Institutes of Health(NIH)R01ES025909,R01DK104656,R01DK080440,R21AA022482,R21AA024935,VA Merit Award 1I01BX002634,P30 DK34989(Yale Liver Center)and the National Natural Scientific Foundation of China(Grant No.81572443).We sincerely thank Dr.Robert A.Harris(Indiana University School of Medicine)for the Pdk4/mice.>.The authors would like to apologise for any inconvenience caused.展开更多
The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work was supported by the Nation...The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work was supported by the National Institutes of Health(NIH)grants(R01DK104656,R01DK080440,R01ES025909,R21AA022482,R21AA024935,R01AA026322 to L.Wang);VA Merit Award(1I01BX002634 to L.Wang);the National Natural Scientific Foundation of China(Grant No.81572443),VA Merit Award(1I01CX000361 to S.Liangpunsakul),NIH(U01AA021840,R01DK107682,R01AA025208,R21AA024935 to S.Liangpunsakul),US DOD(W81XWH-12-1-0497 to S.Liangpunsakul).>.The authors would like to apologise for any inconvenience caused.展开更多
Unclean air discharge refers to the discharge phenomenon of a large number of polluting gases,droplets or solid particles floating in the air,which will cause insulation breakdown and safety accidents for the power tr...Unclean air discharge refers to the discharge phenomenon of a large number of polluting gases,droplets or solid particles floating in the air,which will cause insulation breakdown and safety accidents for the power transmission equipment that have been left outdoors for a long time.In order to investigate the effects of particle concentration,particle size and dielectric constant on DC breakdown characteristics of unclean air gap,a self-made discharge chamber was designed in this study.The air was filtered and passed into the discharge chamber to remove the influence of impurities contained in the air on the experimental results.Then,solid particles with different concentration,particle size and particle dielectric constant were added to the discharge chamber to carry out the DC positive polarity breakdown characteristic experiment.The experimental results show that compared with dry clean air,the presence of solid particle increases the breakdown voltage of the gap,and the increase proportion of breakdown voltage is related to the particle concentration,particle size and particle dielectric constant.With the same particle type and particle size,the increase proportion of breakdown voltage increases with the higher concentration,which up to 10.49%.For further investigating,the fluid mechanics model was selected to simulate the process of streamer discharge in unclean air.The results show that compared with dry clean air,the presence of particles enhances the gap discharge ionisation process,but also enhances the adsorption of particles,and the latter has stronger effect than the former,thus increases the gap breakdown voltage.At the same time,the enhancement of adsorption effect increases the electric field intensity of the gap and speeds up the development process of streamer discharge.展开更多
MicroRNAs （miRNAs） are pivotal modulators of plant development and host-virus interactions. However, the roles and action modes of specific miRNAs involved in viral infection and host susceptibility remain largely u...MicroRNAs （miRNAs） are pivotal modulators of plant development and host-virus interactions. However, the roles and action modes of specific miRNAs involved in viral infection and host susceptibility remain largely unclear. In this study, we show that Rice ragged stunt virus （RRSV） infection caused increased accumulation of miR319 but decreased expression of miR319-regulated TCP （TEOSINTE BRANCHED/ CYCLOIDEA/PCF） genes, especially TCP21, in rice plants. Transgenic rice plants overexpressing miP,319 or downregulating TCP21 exhibited disease-like phenotypes and showed significantly higher susceptibility to RRSV in comparison with the wild-type plants. In contrast, only mild disease symptoms were observed in RRSV-infected lines overexpressing TCP21 and especially in the transgenic plants overexpressing miR319- resistant TCP21. Both RRSV infection and overexpression of miR319 caused the decreased endogenous jasmonic acid （JA） levels along with downregulated expression of JA biosynthesis and signaling-related genes in rice. However, treatment of rice plants with methyl jasmonate alleviated disease symptoms caused by RRSV and reduced virus accumulation. Taken together, our results suggest that the induction of miR319 by RRSV infection in rice suppresses JA-mediated defense to facilitate virus infection and symp- tom development.展开更多
Tillering is a major determinant of rice plant architecture and grain yield.Here,we report that depletion of rice OsNRPD1a and OsNRPD1b,two orthologs of the largest subunit of RNA polymerase IV,leads to a high-tilleri...Tillering is a major determinant of rice plant architecture and grain yield.Here,we report that depletion of rice OsNRPD1a and OsNRPD1b,two orthologs of the largest subunit of RNA polymerase IV,leads to a high-tillering phenotype,in addition to dwarfism and smaller panicles.OsNRPD1a and OsNRPD1b are required for the production of 24-nt small interfering RNAs that direct DNA methylation at transposable elements(TEs)including miniature inverted-repeat TEs(MITEs).Interestingly,many genes are regulated either positively or negatively by TE methylation.Among them,OsMIR156d and OsMIR156j,which promote rice tillering,are repressed by CHH methylation at two MITEs in the promoters.By contrast,D14,which suppresses rice tillering,is activated by CHH methylation at an MITE in its downstream.Our findings reveal regulation of rice tillering by RNA-directed DNA methylation at MITEs and provide potential targets for agronomic trait enhancement through epigenome editing.展开更多
Many microRNAs (miRNAs) are critical regulators of plant antiviral defense.However,little is known about how these miRNAs respond to virus invasion at the transcriptional level.We previously show that defense against ...Many microRNAs (miRNAs) are critical regulators of plant antiviral defense.However,little is known about how these miRNAs respond to virus invasion at the transcriptional level.We previously show that defense against Rice stripe virus (RSV) invasion entailed a reduction of miR528 accumulation in rice,alleviating miR528-mediated degradation of L-Ascorbate Oxidase (AO) mRNA and bolstering the antiviral activity of AO.Here we show that the miR528-A0 defense module is regulated by the transcription factor SPL9.SPL9 displayed high-affinity binding to specific motifs within the promoter region of miR528 and activated the expression of miR528 gene in vivo.Loss-of-function mutations in SPL9 caused a significant reduction in miR528 accumulation but a substantial increase of AO mRNA,resulting in enhanced plant resistance to RSV.Conversely,transgenic overexpression of SPL9 stimulated the expression of miR528 gene,hence lowering the level of AO mRNA and compromising rice defense against RSV.Importantly,gain in RSV susceptibility did not occur when SPL9 was overexpressed in mir528 loss-of-function mutants,or in transgenic rice expressing a miR528-resistant AO.Taken together,the finding of SPL9-mediated transcriptional activation of miR528 expression adds a new regulatory layer to the miR528-A0 antiviral defense pathway.展开更多
The World Health Organization(WHO) has declared coronavirus disease 2019(COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Currently, there is no ...The World Health Organization(WHO) has declared coronavirus disease 2019(COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents,network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs,we focus on the most promising drugs(such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1 a, remdesivir, etc.) that have or will enter the final stage of human testing—phase Ⅲ–Ⅳ clinical trials.展开更多
The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigati...The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigation aimed at identifying the transmission sources in this dengue epidemic. To analyze the phylogenetics of the 2014 dengue strains, the envelope （E） gene sequences from 17 viral strains isolated from 168 dengue patient serum samples were sequenced and a phylogenetic tree was reconstructed. All 17 strains were serotype I strains, including 8 genotype I and 9 genotype V strains. Additionally, 6 genotype I strains that were probably introduced to China from Thailand before 2009 were widely transmitted in the 2013 and 2014 epidemics, and they continued to circulate until 2015, with one affinis strain being found in Singapore. The other 2 genotype I strains were introduced from the Malaya Peninsula in 2014. The transmission source of the 9 genotype V strains was from Malaysia in 2014. DENVs of different serotypes and genotypes co-circulated in the 2014 dengue outbreak in Guangzhou. Moreover, not only had DENV been imported to Guangzhou, but it had also been gradually exported, as the viruses exhibited an enzootic transmission cycle in Guangzhou.展开更多
基金supported by the National Key Research and Development Program of China(2021YFA1500500)。
文摘The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical industry.Here,we precisely constructed carbon nitride supported Pd-based catalysts by a simple impregnation-reduction method.By changing the reduction temperature,catalysts with different oxidation state could be precisely constructed.Moreover,the important correlation between the ratio of Pd^(0)/Pd^(2+)and catalytic activity is revealed during the selective hydrogenation of HMF.The Pd/g—C_(3)N_(4)—300 catalyst with a Pd^(0)/Pd^(2+)ratio of 3/2 showed the highest catalytic activity,which could get 96.9%5-hydroxymethylfurfural conversion and 90.3%2,5-dihydroxymethylfuran selectivity.Further density functional theory calculation revealed that the synergistic effect between Pd0and Pd2+in Pd/g—C_(3)N_(4)—300 system could boost the adsorption of the substrate and the dissociation of hydrogen.In this work,we highlight the important correlation between metal oxidation state and catalytic activity,which provides valuable insights for the rational design of precious metal catalysts for hydrogenation reactions.
基金financially supported by National Natural Science Foundation of China(81700524)Natural Science Foundation of Fujian Province(2022J01866)from Fujian Provincial Department of Science and Technology+1 种基金Key Project of Fujian University of Traditional Chinese Medicine(X2021019)Collaborative Innovation and Platform Establishment Project of Department of Science and Technology of Guangdong Province(2019A050520003)。
文摘Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.
基金the US National Science Foundation and the National Natural Science Foundation of China.
文摘Biodiversity is the basis for ecosystem goods and services that provide for human survival and prosperity. With a rapidly increasing human population and its demands for natural resources, landscapes are being fragmented, habitats are being destroyed, and biodiversity is declining. How can biodiversity be effec- tively conserved in the face of increasing human pressures? In this paper, I review changing perspectives on biodiversity conservation, and discuss their relevance to the practice of biodiversity conservation. The major points include: The notion of balance of nature is a myth rather than a scientific concept; the theory of island biogeography is useful heuristically but flawed practically; the SLOSS debate is intriguing in theory but ir- relevant in reality; the concept of minimum viable population and population viability analysis are useful, but technically inefficient and conceptually inadequate; metapopulation theory is mathematically elegant but ecologically oversimplistic; and integrative perspectives and approaches for biodiversity conservation are needed that incorporate insights from landscape ecology and sustainability science. I further discuss some key principles for regional conservation planning, and argue that the long-term success of biodiversity con- servation in any region will ultimately depend on the economic and social sustainability of that region. Both research and practice in biodiversity conservation, therefore, need to adopt a broader perspective of sustain- ability.
基金financial support from the National Natural Science Foundation of China(Nos.51904310and 51874314)the Fundamental Research Funds for the Central Universities(No.2020YQAQ03)+2 种基金the Open Funds of Key Laboratory of Safety and High-efficiency Coal MiningMinistry of Education(Anhui University of Science and Technology)(No.JYBSYS2019204)the Open Funds of State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University)(No.WS2018B06)。
文摘The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength,meanwhile,its effects on coal deformation are quantitatively evaluated.The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure.Compared with non-gas-saturated coals,the maximum weakening ratios of adsorbed gas to coal strength are 10.58%,18.12%,8.55%and 14.65%under the conditions of confining stress CS=3 MPa and gas pressure GP=1 MPa,CS=3 MPa and GP=2 MPa,CS=4 MPa and GP=1 MPa,and CS=4 MPa and GP=2 MPa,respectively.Furthermore,the maximum weakening ratios of free gas to coal strength are 18.27%,36.54%,14.79%and 29.58%,respectively,under above four conditions.The maximum coal bulk strain decreases as particle sizes of coal powders increase,and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm.Under the same conditions,the coal bulk strain increases with increasing gas pressure,revealing that coal deformation properties can be enhanced by gas.
基金supported by the National Natural Science Foundation of China(32025031,U1905203,31772128,and 32072381)the Fok Ying Tung Education Foundation(161024)the Outstanding Youth Research Program of Fujian Agriculture and Forestry University(xjq202003)。
文摘Plants and viruses coexist in the natural ecosystem for extended periods of time,interacting with each other and even coevolving,maintaining a dynamic balance between plant disease resistance and virus pathogenicity.During virus–host interactions,plants often exhibit abnormal growth and development.However,plants do not passively withstand virus attacks but have evolved sophisticated and effective defense mechanisms to resist,limit,or undermine virus infections.It is widely believed that the initial stage of infection features the most intense interactions between the virus and the host and the greatest variety of activated signal transduction pathways.This review describes the most recent findings in rice antiviral research and discusses a variety of rice antiviral molecular mechanisms,including those based on R genes and recessive resistance,RNA silencing,phytohormone signaling,autophagy and WUSmediated antiviral immunity.Finally,we discuss the challenges and future prospects of breeding rice for enhanced virus resistance.
基金supported by grants from National Basic Research Program of China (No.2011CB504800)National Natural Science Foundation of China (No. 31100128 and 81030031)+3 种基金National Mega Project on Major Drug Development (2009ZX09103-678)National Small Business Innovation and Research (SBIR) Program of Chinathe Technology R & D Program of Jiangsu Province, China (BG20077035 and BG2008662)NIH (RO1-AI041927,RO1-AI050468, RO1-DE014145, and RO1-DE014842)
文摘A quantitative real time reverse-transcription polymerase chain reaction （qRT-PCR） assay with specific primers recommended by the World Health Organization （WHO） has been widely used successfully for detection and monitoring of the pandemic H1N1/2009 influenza A virus. In this study, we report the design and characterization of a novel set of primers to be used in a qRT-PCR assay for detecting the pandemic H1N1/2009 virus. The newly designed primers target three regions that are highly conserved among the hemagglutinin （HA） genes of the pandemic HlN1/2009 viruses and are different from those targeted by the WHO-recommended primers. The qRT-PCR assays with the newly designed primers are highly specific, and as specific as the WHO-recommended primers for detecting pandemic H1N1/2009 viruses and other influenza viruses including influenza B viruses and influenza A viruses of human, swine, and raccoon dog origin. Furthermore, the qRT-PCR assays with the newly designed primers appeared to be at least 10-fold more sensitive than those with the WHO-recommended primers as the detection limits of the assays with our primers and the WHO-recommended primers were 2.5 and 25 copies of target RNA per reaction, respectively. When tested with 83 clinical samples, 32 were detected to be positive using the qRT-PCR assays with our designed primers, while only 25 were positive by the assays with the WHO-recommended primers. These results suggest that the qRT-PCR system with the newly designed primers represent a highly sensitive assay for diagnosis of the pandemic HIN1/2009 virus infection.
基金supports from the General Program (No. 31871016)the National Key Scientific Instrument and Equipment Development Projects (No. 61827806) from the National Natural Science Foundation of China+3 种基金the National Major Science and Technology Projects (No. 2018ZX10732401-003-007)the National Key Research and Development Program (No. 2016YFC1101302) from the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China (No. 81770719)Science and Technology Department of Zhejiang Province (No. 2019C03029)
文摘Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a“single pot”design,which inevitably requires holistic analysis and limits parallel processing.Here,we developed a digital organ-on-a-chip by combining a microwell array with cellular microspheres,which significantly increased the parallelism over traditional organ-on-a-chip for drug development.Up to 127 uniform liver cancer microspheres in this digital organ-on-a-chip format served as individual analytical units,allowing for analysis with high consistency and quick response.Our platform displayed evident anti-cancer efficacy at a concentration of 10μM for sorafenib,and had greater alignment than the“single pot”organ-on-a-chip with a previous in vivo study.In addition,this digital organ-on-a-chip demonstrated the treatment efficacy of natural killer cell-derived extracellular vesicles for liver cancer at 50μg/mL.The successful development of this digital organ-on-a-chip platform provides high-parallelism and a low-variability analytical tool for toxicity assessment and the exploration of new anticancer modalities,thereby accelerating the joint endeavor to combat cancer.
文摘The global climate has changed substantially over the last 100 years,and associated changes in species distribution limits have occurred in recent decades.Climate change presents a challenge for biodiversity conservation on a global scale.The ability to detect changes in species distributions and attribute them to past climate change is crucial for the accurate prediction of future species distributions and for biodiversity conservation.This study proposes a technique for the quantitative detection of species distribution changes and their attribution to past climate change.An attribution value was defined to describe the extent to which the distributional changes for observed species could be attributed to climate change.The calculation thereof involved the following steps:(1)construction of a time series of observed species distributions and climatic factors,(2)estimation of the correlations between changes in species distributions and climatic factors,(3)prediction of changes in species distributions as driven by climatic factors,(4)estimation of the consistency between observed and predicted changes in species distributions,and(5)estimation of the attribution value.Furthermore,using nine snake species found in China as examples,we demonstrated in detail the practical application of this technique.This technique can be used to identify,based on global species distribution and climate data,the effects of climate change on species distributions over the past years on a global scale.
文摘Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer japonica rice lines along with their parents. Two genetic models and their corresponding statistical methods for quantitative traits of triploid seeds in cereal crops were used for the analysis. The first was the unconditional genetic model, which refers to the analysis of cumulative measurements (from flowering to a specific time) along the developmental stages, while the second was the conditional genetic model, which relates to analysis from one developmental stage to another stage (t - 1→t). The results showed that leucine content of indica-japonica hybrid rice was controlled by the expression of triploid endosperm effect (endosperm additive effect and endosperm dominant effect), cytoplasm effect, diploid maternal plant effect (maternal additive effect and maternal dominant effect) and their environmental interaction effects. Of these effects, endosperm dominant effect and maternal dominant effect were more important at the earlier stages, while endosperm additive effect and maternal additive effect were more important at the later stages of rice grain development under both unconditional and conditional genetic analyses. Due to the high heritabilities, which came from endosperm, maternal and cytoplasm effects for leucine content at different developmental stages, selection for leucine content of indica-japonica hybrid rice would be more efficient at early generations in breeding programs.
基金the National Natural Science Foundation of China for financial support(31530062 and 32025031)。
文摘Plant viruses are a group of intracellular pathogens that persistently threaten global food security.Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years,including basic research and technologies for preventing and controlling plant viral diseases.Here,we review these milestones and advances,including the identification of new crop-infecting viruses,dissection of pathogenic mechanisms of multiple viruses,examination of multilayered interactions among viruses,their host plants,and virus-transmitting arthropod vectors,and in-depth interrogation of plantencoded resistance and susceptibility determinants.Notably,various plant virus-based vectors have also been successfully developed for gene function studies and target gene expression in plants.We also recommend future plant virology studies in China.
基金supported by the National Natural Science Foundation of China(81730061,81802008)the Guangdong Basic and Applied Basic Research Foundation(2021A1515011272).
文摘Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.
基金supported by the National Natural Science Foundation of China(81730061 to J.W.,82072834 to X.C.,32100697 to L.Z.and 32200117 to P.P.)China Postdoctoral Science Foundation(2020M683177 to P.P.,2020T130046ZX to P.P.)+2 种基金Open Research Fund Program of the State Key Laboratory of Virology of China(2021KF003 to P.P.)Open Research Fund Program of Guangdong Provincial Key Laboratory of Virology(2022KF003 to P.P.)R&D Program of Guangzhou Laboratory(SRPG22-006 to Q.Z.)。
文摘Viral infection in respiratory tract usually leads to cell death,impairing respiratory function to cause severe disease.However,the diversity of clinical manifestations of SARS-CoV-2 infection increases the complexity and difficulty of viral infection prevention,and especially the high-frequency asymptomatic infection increases the risk of virus transmission.Studying how SARS-CoV-2 affects apoptotic pathway may help to understand the pathological process of its infection.Here,we uncovered SARS-CoV-2 imployed a distinct anti-apoptotic mechanism via its N protein.We found SARS-CoV-2 virus-like particles(trVLP)suppressed cell apoptosis,but the trVLP lacking N protein didn’t.Further study verified that N protein repressed cell apoptosis in cultured cells,human lung organoids and mice.Mechanistically,N protein specifically interacted with anti-apoptotic protein MCL-1,and recruited a deubiquitinating enzyme USP15 to remove the K63-linked ubiquitination of MCL-1,which stabilized this protein and promoted it to hijack Bak in mitochondria.Importantly,N protein promoted the replications of IAV,DENV and ZIKV,and exacerbated death of IAV-infected mice,all of which could be blocked by a MCL-1 specific inhibitor,S63845.Altogether,we identifed a distinct anti-apoptotic function of the N protein,through which it promoted viral replication.These may explain how SARS-CoV-2 effectively replicates in asymptomatic individuals without cuasing respiratory dysfunction,and indicate a risk of enhanced coinfection with other viruses.We anticipate that abrogating the N/MCL-1-dominated apoptosis repression is conducive to the treatments of SARS-CoV-2 infection as well as coinfections with other viruses.
文摘The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work is supported by the US National Institutes of Health(NIH)R01ES025909,R01DK104656,R01DK080440,R21AA022482,R21AA024935,VA Merit Award 1I01BX002634,P30 DK34989(Yale Liver Center)and the National Natural Scientific Foundation of China(Grant No.81572443).We sincerely thank Dr.Robert A.Harris(Indiana University School of Medicine)for the Pdk4/mice.>.The authors would like to apologise for any inconvenience caused.
文摘The authors regret<the text“to L.Wang”should be removed from the National Natural Scientific Foundation of China(Grant No.81572443).The correct acknowledgement should read as:This work was supported by the National Institutes of Health(NIH)grants(R01DK104656,R01DK080440,R01ES025909,R21AA022482,R21AA024935,R01AA026322 to L.Wang);VA Merit Award(1I01BX002634 to L.Wang);the National Natural Scientific Foundation of China(Grant No.81572443),VA Merit Award(1I01CX000361 to S.Liangpunsakul),NIH(U01AA021840,R01DK107682,R01AA025208,R21AA024935 to S.Liangpunsakul),US DOD(W81XWH-12-1-0497 to S.Liangpunsakul).>.The authors would like to apologise for any inconvenience caused.
基金National Natural Science Foundation of China,Grant/Award Number:52077018。
文摘Unclean air discharge refers to the discharge phenomenon of a large number of polluting gases,droplets or solid particles floating in the air,which will cause insulation breakdown and safety accidents for the power transmission equipment that have been left outdoors for a long time.In order to investigate the effects of particle concentration,particle size and dielectric constant on DC breakdown characteristics of unclean air gap,a self-made discharge chamber was designed in this study.The air was filtered and passed into the discharge chamber to remove the influence of impurities contained in the air on the experimental results.Then,solid particles with different concentration,particle size and particle dielectric constant were added to the discharge chamber to carry out the DC positive polarity breakdown characteristic experiment.The experimental results show that compared with dry clean air,the presence of solid particle increases the breakdown voltage of the gap,and the increase proportion of breakdown voltage is related to the particle concentration,particle size and particle dielectric constant.With the same particle type and particle size,the increase proportion of breakdown voltage increases with the higher concentration,which up to 10.49%.For further investigating,the fluid mechanics model was selected to simulate the process of streamer discharge in unclean air.The results show that compared with dry clean air,the presence of particles enhances the gap discharge ionisation process,but also enhances the adsorption of particles,and the latter has stronger effect than the former,thus increases the gap breakdown voltage.At the same time,the enhancement of adsorption effect increases the electric field intensity of the gap and speeds up the development process of streamer discharge.
文摘MicroRNAs （miRNAs） are pivotal modulators of plant development and host-virus interactions. However, the roles and action modes of specific miRNAs involved in viral infection and host susceptibility remain largely unclear. In this study, we show that Rice ragged stunt virus （RRSV） infection caused increased accumulation of miR319 but decreased expression of miR319-regulated TCP （TEOSINTE BRANCHED/ CYCLOIDEA/PCF） genes, especially TCP21, in rice plants. Transgenic rice plants overexpressing miP,319 or downregulating TCP21 exhibited disease-like phenotypes and showed significantly higher susceptibility to RRSV in comparison with the wild-type plants. In contrast, only mild disease symptoms were observed in RRSV-infected lines overexpressing TCP21 and especially in the transgenic plants overexpressing miR319- resistant TCP21. Both RRSV infection and overexpression of miR319 caused the decreased endogenous jasmonic acid （JA） levels along with downregulated expression of JA biosynthesis and signaling-related genes in rice. However, treatment of rice plants with methyl jasmonate alleviated disease symptoms caused by RRSV and reduced virus accumulation. Taken together, our results suggest that the induction of miR319 by RRSV infection in rice suppresses JA-mediated defense to facilitate virus infection and symp- tom development.
基金This work was supported by grants from National Natural Science Foundation of China(grant no.31788103)to J.L.and Y.Q.and the National Key R&D Program of China(grant no.2016YFA0500800)to Y.Q.Y.Q.is a visiting investigator of the CAS Center for Excellence in Molecular Plant Sciences.
文摘Tillering is a major determinant of rice plant architecture and grain yield.Here,we report that depletion of rice OsNRPD1a and OsNRPD1b,two orthologs of the largest subunit of RNA polymerase IV,leads to a high-tillering phenotype,in addition to dwarfism and smaller panicles.OsNRPD1a and OsNRPD1b are required for the production of 24-nt small interfering RNAs that direct DNA methylation at transposable elements(TEs)including miniature inverted-repeat TEs(MITEs).Interestingly,many genes are regulated either positively or negatively by TE methylation.Among them,OsMIR156d and OsMIR156j,which promote rice tillering,are repressed by CHH methylation at two MITEs in the promoters.By contrast,D14,which suppresses rice tillering,is activated by CHH methylation at an MITE in its downstream.Our findings reveal regulation of rice tillering by RNA-directed DNA methylation at MITEs and provide potential targets for agronomic trait enhancement through epigenome editing.
基金supported by grants from the Natural Science Foundation of China (31530062,31420103904 and 31722045)Transgenic Research Program (2016ZX08010-001,2016ZX08009003-001)Y.L.,and GARS- 01-06 to 乙H.X.,and Y.L.:ZY was supported by the National Postdoctoral Program for Innovative Talents (BX201700004).
文摘Many microRNAs (miRNAs) are critical regulators of plant antiviral defense.However,little is known about how these miRNAs respond to virus invasion at the transcriptional level.We previously show that defense against Rice stripe virus (RSV) invasion entailed a reduction of miR528 accumulation in rice,alleviating miR528-mediated degradation of L-Ascorbate Oxidase (AO) mRNA and bolstering the antiviral activity of AO.Here we show that the miR528-A0 defense module is regulated by the transcription factor SPL9.SPL9 displayed high-affinity binding to specific motifs within the promoter region of miR528 and activated the expression of miR528 gene in vivo.Loss-of-function mutations in SPL9 caused a significant reduction in miR528 accumulation but a substantial increase of AO mRNA,resulting in enhanced plant resistance to RSV.Conversely,transgenic overexpression of SPL9 stimulated the expression of miR528 gene,hence lowering the level of AO mRNA and compromising rice defense against RSV.Importantly,gain in RSV susceptibility did not occur when SPL9 was overexpressed in mir528 loss-of-function mutants,or in transgenic rice expressing a miR528-resistant AO.Taken together,the finding of SPL9-mediated transcriptional activation of miR528 expression adds a new regulatory layer to the miR528-A0 antiviral defense pathway.
基金supported by grants from the National Key Research and Development Program of China(2018YFE0204503)Natural Science Foundation of Guangdong Province (20183030312010)the Guangzhou Healthcare Collaborative Innovation Major Project (201803040004 and201803040007)。
文摘The World Health Organization(WHO) has declared coronavirus disease 2019(COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents,network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs,we focus on the most promising drugs(such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1 a, remdesivir, etc.) that have or will enter the final stage of human testing—phase Ⅲ–Ⅳ clinical trials.
基金supported by the Guangdong Natural Science Foundation (No. S2012030006598)the Science & Technology Planning Project of Guangdong Province of China (No. 2013A020229007)the Innovative Program of the State Key Laboratory of Virology (No. 2016KF001)
文摘The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigation aimed at identifying the transmission sources in this dengue epidemic. To analyze the phylogenetics of the 2014 dengue strains, the envelope （E） gene sequences from 17 viral strains isolated from 168 dengue patient serum samples were sequenced and a phylogenetic tree was reconstructed. All 17 strains were serotype I strains, including 8 genotype I and 9 genotype V strains. Additionally, 6 genotype I strains that were probably introduced to China from Thailand before 2009 were widely transmitted in the 2013 and 2014 epidemics, and they continued to circulate until 2015, with one affinis strain being found in Singapore. The other 2 genotype I strains were introduced from the Malaya Peninsula in 2014. The transmission source of the 9 genotype V strains was from Malaysia in 2014. DENVs of different serotypes and genotypes co-circulated in the 2014 dengue outbreak in Guangzhou. Moreover, not only had DENV been imported to Guangzhou, but it had also been gradually exported, as the viruses exhibited an enzootic transmission cycle in Guangzhou.
