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Owing to the strong Hg-Se interaction, Se-containing materials are promising for the uptake and immobilization of Hg(II) ions; compared with metal selenides or selenized compounds, elemental Se contains the highest ratio of Se. However, it remains a challenge to fully expose all the potential Se binding sites and achieve high utilization efficiency of elemental Se. Through rational design on the structure, dispersity, and size of materials, Se/CNF aerogels composed of abundant well-dispersed and amorphous nano-Se have been prepared and applied for the high-efficient uptake and immobilization of Hg(II) ions. The well-dispersion of nano-Se increases the exposure of Se sites, the amorphous structure benefits the easy cleavage of Se-Se bonds, the 3D porous networks of aerogels permit fast ions transport and easy operation. Benefiting from the combination effect of strong Hg-Se interaction and sufficient exposure of Se-enriched sites, the Se/CNF aerogels demonstrate strong binding ability (Kd = 3.8 ×105 mL·g-1), high capacity (943.4 mg·g-1), and preeminent selectivity (αMHg > 100) towards highly toxic Hg(II) ions. Notably, the utilization efficiency of Se in Se/CNF aerogels is as high as 99.5%. Moreover, the strong Hg-Se interaction and extraordinary stability of HgSe could minimize the environmental impact of the spent Se/CNF adsorbents after its disposal.
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Avian influenza virus (AIV) subtype H9N2 is the most widespread AIV in poultry worldwide, causing great economic losses in the global poultry industry. Chickens and ducks are the major hosts and play essential roles in the transmission and evolution of H9N2 AIV. Vaccines are considered an effective strategy for fighting H9N2 infection. However, due to the differences in immune responses to infection, vaccines against H9N2 AIV suitable for use in both chickens and ducks have not been well studied. This study developed an inactivated H9N2 vaccine based on a duck-origin H9N2 AIV and assessed its effectiveness in the laboratory. The results showed that the inactivated H9N2 vaccine elicited significant haemagglutination inhibition (HI) antibodies in both chickens and ducks. Virus challenge experiments revealed that immunization with this vaccine significantly blocked virus shedding after infection by both homogenous and heterologous H9N2 viruses. The vaccine was efficacious in chicken and duck flocks under normal field conditions. We also found that egg-yolk antibodies were produced by laying birds immunized with the inactivated vaccine, and high levels of maternal antibodies were detected in the serum of the offspring. Taken together, our study showed that this inactivated H9N2 vaccine could be extremely favourable for the prevention of H9N2 in both chickens and ducks.
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Goose astrovirus (GAstV) leads to viscera and joints urate deposition in 1- to 20-day-old goslings, with a mortality rate of up to 50%, posing a severe threat to entire colonies; however, there is no efficient prevention and control method for GAstV infection. This study describes a prophylactic anti-GAstV strategy based on the specific immunoglobulin Y (IgY) from egg yolk. The specific IgY was produced by 22-week-old laying hens intramuscularly immunized with the inactivated GAstV three consecutive times, with 2-week intervals. The egg yolk was collected weekly after the immunization and the anti-GAstV IgY titer was monitored using an agar gel immune diffusion assay (AGID). The results revealed that the AGID titer began to increase on day 7, reached a peak on day 49, and remained at a high level until day 77 after the first immunization. The specific IgY was prepared from the combinations of egg yolk from day 49 to day 77 through PEG-6000 precipitation. Animal experiments were conducted to evaluate the effects of prevention and treatment. The result of the minimum prophylactic dose of the IgY showed that the protection rate was 90.9% when 2.5 mg was administrated. Results of the prevention and the treatment experiments showed prevention and cure rates of over 80% when yolk antibody was administered in the early stages of the GAstV infection. These results suggested that the specific IgY obtained from immunized hens with the inactivated GAstV could be a novel strategy for preventing and treating GAstV infection.
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Anthocyanins can help plants adapt and resist adverse environments and have important nutritional and medicinal effects on human beings. However, how environmental factors affect the anthocyanins accumulation of plants and how to improve the anthocyanins content of plants in different soils needs further exploration. Hence, this study aimed to investigate the effects of environmental factors on the accumulation of cyanidin, petunidin, malvidin, and delphinidin in the fruits of Lycium ruthenicum in sandy desert grassland (SS), gravel desert grassland (GD), and saline-alkali desert grassland (SD) in the lower reaches of the Shiyang River Basin. The variable importance screened the key environmental factors affecting anthocyanin accumulation in projection (VIP) and multiple stepwise regressions. The structural equation model (SEM) was established to understand how the climate and soil factors affect the total anthocyanin accumulation. For establishing soil nutrient optimization schemes by partial least squares regression (PLS) and the simplex algorithm used to improve the anthocyanin content in different types of desert grassland. In SS, electrical conductivity (EC) and microbial biomass carbon (SMBC) showed highly significant and positive effects on the content of total anthocyanin, cyanidin, and petunidin. In GD, soil moisture and microbial biomass nitrogen (SNBN) significantly negatively affected total anthocyanin content. In SD, catalase (CAT), phosphatase (PHO), and total potassium (TK) had the greatest impact on total anthocyanin content. It is indicated that the targeted improvement measures are necessary to increase anthocyanin content in the fruit of Lycium ruthenicum.
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Antocianinas , Lycium , Humanos , Antocianinas/química , Lycium/química , Frutas , Pradera , SueloRESUMEN
Kinetic and affinity analysis of protein interactions reveals information on their related activities in biological processes. Herein, we established a system for evaluating the kinetics and affinity of the interaction between protein A and various IgG species on the surface of silica spheres of silica colloidal crystal (SCC) films by the extraordinary optical interference capabilities of 190 nm silica spheres after self-assembly. The equilibrium association constant (KA) was calculated by the equilibrium Langmuir model and nonlinear least-squares analysis of time-dependent data. The relative protein A/IgG binding affinity is human > rabbit >cow >goat. In addition, the competitive interaction of distinct species of IgG with protein A at the interface of SCC films was studied and performed. These findings may help with the use of protein A and other recognition components in a number of sensor types. Furthermore, this research might offer a novel approach to determining the kinetics and affinity of proteins on the surface of spheres particles, which may contribute to the development of the application of spheres particles in pharmaceutical science, biomedical engineering, and other techniques.
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Tembusu virus (TMUV) is an avian-origined flavivirus that is prevalent in ducks and geese. TMUV causes reduced egg production and neurological problems, resulting in profound economic losses to the waterfowl industry. In the viral life cycle, cellular factors are required for viral entry, replication, assembly, release and so on. Heat shock protein 70 (HSP70) is reported to be involved in the replication of multiple viruses. In this study, we explored the roles of HSP70 in the TMUV life cycle. The results showed that TMUV infection induced HSP70 expression starting 12 h post-infection. An HSP70 inhibitor reduced TMUV viral RNA production and the number of virus particles, whereas an HSP70 activator enhanced the amount of viral RNA and virions that released from the cells. Further analysis revealed that HSP70 played important roles in the postentry stages of the TMUV life cycle, including viral replication, assembly and release. We also found that inhibition of HSP70 expression significantly reduced TMUV-induced apoptosis. Additionally, incubation of TMUV particles with an anti-HSP70 antibody significantly reduced viral infectivity, suggesting an association between HSP70 and TMUV particles. These results implicate HSP70 in the life cycle of TMUV, and therefore, targeting HSP70 may be a strategy for developing an anti-TMUV therapy.
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Infecciones por Flavivirus , Flavivirus , Enfermedades de las Aves de Corral , Animales , Línea Celular , Patos , Flavivirus/genética , Infecciones por Flavivirus/veterinaria , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismoRESUMEN
Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused significant economic losses to the duck industry in China since 2010 due to egg production losses and neurological dysfunction. DTMUV is a public health concern because the infection spreads rapidly among birds. Retinoic acid-inducible gene-I (RIG-I)serves as an innate immune sensor and plays a key role in host antiviral defenses. Tripartite motif-containing protein 25 (TRIM25), an E3 ubiquitin ligase, is pivotal for RIG-I ubiquitination and activation. In addition, TRIM25 acts as an interferon-stimulated gene and mediates the antiviral activity. However, the effect of duck TRIM25 on DTMUV has not been assessed. Herein, we reportthe antiviral function of TRIM25 against DTMUV. First, we constructed the pcDNA3.1-c-myc-duTRIM25 plasmid. TRIM25 has a 2052 bp open reading frame that encodes a predicted 684 amino acid protein consisting of a RING finger domain, a B-box domain, a coiled-coil domain, and a PRY/SPRY domain. The protein sequence identity with chicken, mouse, and human TRIM25 is 69.7, 47.8, and 48.3%, respectively. TRIM25 was upregulated in BHK-21 cells, duck embryo fibroblasts, and 293T cellsupon DTMUV infection. The expression of viral RNA and proteins was significantly lower in cells over expressing TRIM25 than in control cells. Furthermore, siRNA-mediated silencing of TRIM25 increased the production of viral progeny. These results help elucidate the molecular mechanisms underlying the host response to DTMUV infection and suggest potential control measures for DTMUV outbreaks.
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Relationships between biodiversity and multiple ecosystem functions (that is, ecosystem multifunctionality) are context-dependent. Both plant and soil microbial diversity have been reported to regulate ecosystem multifunctionality, but how their relative importance varies along environmental gradients remains poorly understood. Here, we relate plant and microbial diversity to soil multifunctionality across 130 dryland sites along a 4,000 km aridity gradient in northern China. Our results show a strong positive association between plant species richness and soil multifunctionality in less arid regions, whereas microbial diversity, in particular of fungi, is positively associated with multifunctionality in more arid regions. This shift in the relationships between plant or microbial diversity and soil multifunctionality occur at an aridity level of â¼0.8, the boundary between semiarid and arid climates, which is predicted to advance geographically â¼28% by the end of the current century. Our study highlights that biodiversity loss of plants and soil microorganisms may have especially strong consequences under low and high aridity conditions, respectively, which calls for climate-specific biodiversity conservation strategies to mitigate the effects of aridification.
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Biodiversidad , Clima Desértico , Hongos/metabolismo , Desarrollo de la Planta , Plantas/metabolismo , Suelo/química , China , Ecosistema , Hongos/clasificación , Hongos/crecimiento & desarrollo , Geografía , Concentración de Iones de Hidrógeno , Modelos Teóricos , Plantas/clasificación , Microbiología del Suelo , Especificidad de la Especie , Agua/metabolismoRESUMEN
Given the fact that excessive levels of reactive oxygen species (ROS) induce damage to proteins, lipids, and DNA, various ROS-generating agents and strategies have been explored to induce cell death and tumor destruction by generating ROS above toxic threshold. Unfortunately, hypoxia in tumor microenvironment (TME) not only promotes tumor metastasis but also enhances tumor resistance to the ROS-generated cancer therapies, thus leading to ineffective therapeutic outcomes. A variety of nanotechnology-based approaches that generate or release O2 continuously to overcome hypoxia in TME have showed promising results to improve the efficacy of ROS-generated cancer therapy. In this minireview, we present an overview of current nanomaterial-based strategies for advanced cancer therapy by modulating the hypoxia in the TME and promoting ROS generation. Particular emphasis is put on the O2 supply capability and mechanism of these nanoplatforms. Future challenges and opportunities of design consideration are also discussed. We believe that this review may provide some useful inspiration for the design and construction of other advanced nanomaterials with O2 supply ability for overcoming the tumor hypoxia-associated resistance of ROS-mediated cancer therapy and thus promoting ROS-generated cancer therapeutics.
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Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused huge economic losses to the duck industry in China since 2010. Moreover, the infection has spread rapidly, resulted in a potential public health concern. To improve our understanding of the host cellular responses to virus infection and the pathogenesis of DTMUV infection, we used RNA-Seq to detect the gene changes in DF-1 cells infected and mock-infected with DTMUV. A total of 663 differentially-expressed genes (DEGs) were identified in DTMUV-infected compared with mock-infected DF-1 cells at 24 h post-infection (hpi), among which 590 were up regulated and 73 were down regulated. Gene Ontology analysis indicated that the DEGs were mainly involved in cellular process, immune system processes, metabolic processes, and signal-organism process. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DEGs were mainly involved in several signaling pathways such as Toll-like receptor signaling, Jak-STAT signaling, RIG-I-like receptor signaling and AGE-RAGE signaling pathway. Moreover, some selected DEGs were further confirmed by real-time PCR and the results were consistent with the sequencing data. To our knowledge, this study is the first to analyze the transcriptomic change in DF-1 cells following DTMUV infection. We believe that our research provides useful information in better understanding the host response to DTMUV infection and the inherent mechanism of DTMUV replication and pathogenicity.
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Patos/virología , Flavivirus/fisiología , Animales , Línea Celular , China , Fibroblastos/virología , Flavivirus/patogenicidad , Expresión Génica , Perfilación de la Expresión Génica/veterinaria , RNA-Seq , Receptores Toll-Like/metabolismo , Replicación ViralRESUMEN
MicroRNA (miRNA) plays a key role in virus-host interactions. Here, we employed deep sequencing technology to determine cellular miRNA expression profiles in chicken dendritic cells infected with H9N2 avian influenza virus (AIV). A total of 66 known and 36 novel miRNAs were differently expressed upon H9N2 infection, including 72 up-regulated and 30 down-regulated miRNAs. Functional analysis showed that the predicted targets of these miRNAs were significantly enriched in several pathways including endocytosis, notch, lysosome, p53, RIG-I-like and NOD-like receptor signaling pathways. These data provide valuable information for further investigating the roles of miRNA in AIV pathogenesis and host defense response.
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Pollos/genética , Regulación de la Expresión Génica , Subtipo H9N2 del Virus de la Influenza A/fisiología , Gripe Aviar/virología , MicroARNs/genética , Enfermedades de las Aves de Corral/virología , Animales , Pollos/metabolismo , Regulación hacia Abajo , Interacciones Huésped-Patógeno , MicroARNs/metabolismo , Regulación hacia Arriba , Replicación ViralRESUMEN
Tembusu virus (TMUV) is a newly emerging flavivirus and has caused significant economic loss to the poultry industry in China. To date, the entry of TMUV into host cells remains poorly understood. Here, the mechanism of TMUV entry into BHK-21 cells was investigated. The depletion of cellular cholesterol by methyl-ß-cyclodextrin led to a significant decline in the titers and RNA levels of the infectious TMUV. This reduction was restored by supplementation of exogenous cholesterol. Membrane cholesterol depletion mainly blocked viral internalization but not attachment. However, viral infection was unaffected by genistein treatment or caveolin-1 silencing by small interfering RNA. In addition, clathrin-mediated endocytosis might be utilized in TMUV entry given that the viral infection was inhibited by knockdown of clathrin heavy chain and treatment of chlorpromazine (CPZ). Moreover, the number of internalized virus particles decreased under CPZ treatment. Dynasore inhibited TMUV entry suggesting a role for dynamin. Our results reveal that TMUV entry into BHK-21 cells is dependent on cholesterol, clathrin and dynamin but not caveolae.
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Colesterol , Clatrina , Endocitosis , Flavivirus , Internalización del Virus , Animales , Línea Celular , Cricetinae , Flavivirus/fisiologíaRESUMEN
The outbreak and spread of Tembusu virus (TMUV) has caused very large losses in the waterfowl-breeding industry since 2010. The viral envelope (E) protein, the principal surface protein of viral particles, plays a vital role in viral entry and fusion. In this study, two peptides derived from domain II (DII) and the stem of the TMUV envelope protein, TP1 and TP2, respectively, were tested for their antiviral activity. TP1 and TP2 inhibited TMUV infection in BHK-21 cells, and their 50% inhibitory concentrations (IC50) were 14.19 mg/L and 7.64 mg/L, respectively. Viral inhibition assays in different cell lines of avian origin showed that the inhibitory effects of TP1 and TP2 are not cell type dependent. Moreover, TP2 also exhibited inhibitory activity against Japanese encephalitis virus (JEV) infection. The two peptides inhibited antibody-mediated TMUV infection of duck peripheral blood lymphocytes. Co-immunoprecipitation assays and indirect enzyme-linked immunosorbent assays (ELISAs) indicated that both peptides interact with the surface of the TMUV virion. RNase digestion assays confirmed the release of viral RNA following incubation with TP1, while incubation with TP1 or TP2 interfered with the binding between TMUV and cells. Taken together, these results show that TP1 and TP2 may be developed into antiviral treatments against TMUV infection.
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Antivirales/farmacología , Flavivirus/efectos de los fármacos , Péptidos/farmacología , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/farmacología , Animales , Acrecentamiento Dependiente de Anticuerpo , Antivirales/química , Línea Celular , Cricetinae , Patos , Concentración 50 Inhibidora , Linfocitos/inmunología , Linfocitos/virología , Péptidos/química , ARN Viral/metabolismo , Organismos Libres de Patógenos EspecíficosRESUMEN
This data article reports the global gene expression analysis data of chicken DCs infected with H9N2 avian influenza virus (AIV) compared with mock infection. The differentially expressed genes (DEGs), and the data of GO enrichment analysis and KEGG pathway analysis for DEGs were reported here. In addition, some of these DEGs associated with innate immune response and antigen presentation were also verified by qPCR. The replication of H9N2 AIV in DCs, and the viability kinetic of DCs during H9N2 AIV infection, and the primers for qPCR were also reported in this data article. The data presented here was used on the research article entitled "Transcriptomic profile of chicken bone marrow-derive dendritic cells in response to H9N2 avianinfluenza A virus".
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Precipitation is known to have legacy effects on plant diversity and production of many terrestrial ecosystems. Precipitation regimes are expected to become more variable with increasing extreme precipitation events. However, how previous-year precipitation regimes affect the current-year aboveground biomass (AGB) remains largely unknown. Here we measured long-term (2004-2017) AGB in a semi-arid grassland of the Chinese Loess Plateau to evaluate the impact of previous-year precipitation amount on current-year AGB. Furthermore, to assess the response of current-year AGB to previous-year precipitation regimes, we conducted a field manipulation experiment that included three precipitation regimes during 2014-2017: (i) ambient precipitation, (ii) monthly added four 5 mm rain events, and (iii) monthly added one 20 mm event. Both the long-term (2004-2017) observations under ambient precipitation and short-term (2014-2017) measurements under manipulative treatments showed significant positive effects of previous-year precipitation on current-year AGB. Our path analysis suggested that previous-year precipitation frequency had negative effects on the current-year density and mean height of grass (Leymus secalinus) while had positive effects on forb (Artemisia capillaris). The forb had much smaller height and AGB (65% and 53% less, respectively) than the grass. Consequently, the AGB reduced in the weekly small events treatment, causing the sensitivity of AGB to precipitation to decrease. Therefore, our findings indicated that the impacts of precipitation regimes on plant community dynamics should be taken into consideration while assessing the precipitation legacy effect on ecosystem production.
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Biomasa , Pradera , Poaceae , LluviaRESUMEN
Avian influenza subtype H9N2 infection is a mild but highly contagious disease that is associated with a decrease in the efficacy of vaccine interventions, and an increase in susceptibility to secondary infections in poultry. However, the immune evasion mechanism of H9N2 avian influenza viruses (AIVs) in chickens is poorly understood. Dendritic cells (DCs) are immune cells of major importance, involved in innate immune responses against viruses, but also in the setting of adaptive immune response due to their high ability to present viral antigen. Therefore, in the present study we used high-throughput RNA-sequencing technology at the transcriptome level to identify the differentially expressed genes (DEGs) between chicken DCs infected with H9N2 virus and mock-infected DCs. We identified 4151 upregulated DEGs and 2138 downregulated DEGs. Further enrichment analysis showed that the upregulated DEGs were enriched in the biological processes mainly involved in signal transduction, transmembrane transport, and innate immune/inflammatory responses. In contrast, the downregulated DEGs were associated with the biological processes mainly including metabolic process, and MHC class I antigen processing and presentation. In addition, 49 of these immune-related DEGs were validated by reverse transcription quantitative PCR (RT-qPCR). Collectively, these data suggest that H9N2 virus infection may enhance the signal transduction, and innate immune responses in chicken DCs, but impair their metabolic functions and antigen-presenting responses, which provide helpful insight into the pathogenesis of H9N2 AIVs in chickens and managing this infection in poultry farms.
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Células de la Médula Ósea/virología , Células Dendríticas/inmunología , Células Dendríticas/virología , Inmunidad Innata/genética , Subtipo H9N2 del Virus de la Influenza A/inmunología , Animales , Células de la Médula Ósea/inmunología , Células Cultivadas , Pollos , Regulación hacia Abajo , Perfilación de la Expresión Génica , Evasión Inmune/genética , Organismos Libres de Patógenos Específicos , Regulación hacia ArribaRESUMEN
Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused massive economic losses to the duck industry in China. The cellular factors required for DTMUV replication have been poorly studied. The ubiquitin-proteasome system (UPS), the major intracellular proteolytic pathway, mediates diverse cellular processes, including endocytosis and signal transduction, which may be involved in the entry of virus. In the present study, we explored the interplay between DTMUV replication and the UPS in BHK-21â¯cells and found that treatment with proteasome inhibitor (MG132 and lactacystin) significantly decreased the DTMUV progency at the early infection stage. We further revealed that inhibition of the UPS mainly occurs on the level of viral protein expression and RNA transcription. In addition, using specific siRNAs targeting ubiquitin reduces the production of viral progeny. In the presence of MG132 the staining for the envelope protein of DTMUV was dramatically reduced in comparison with the untreated control cells. Overall, our observations reveal an important role of the UPS in multiple steps of the DTMUV infection cycle and identify the UPS as a potential drug target to modulate the impact of DTMUV infection.
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Flavivirus/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina/metabolismo , Replicación Viral/fisiología , Acetilcisteína/análogos & derivados , Acetilcisteína/antagonistas & inhibidores , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Patos , Flavivirus/efectos de los fármacos , Flavivirus/patogenicidad , Técnicas de Silenciamiento del Gen , Leupeptinas/antagonistas & inhibidores , Enfermedades de las Aves de Corral/virología , Complejo de la Endopetidasa Proteasomal/efectos de los fármacos , ARN Interferente Pequeño , Transfección , Ubiquitina/efectos de los fármacos , Ubiquitina/genética , Proteínas del Envoltorio Viral , Internalización del VirusRESUMEN
BACKGROUND: Tembusu virus (TMUV), classified in the genus Flavivirus, causes reduced egg production and neurological problems in poultry. Flavivirus replication depends on the host endoplasmic reticulum (ER) and induces ER stress that leads to activation of the cellular unfolded protein response (UPR), an important signalling pathway that regulates many biological functions involved in viral pathogenesis and innate immunity. However, the mechanism of TMUV-induced UPR activation remains unclear. RESULTS: In this study, we systematically investigated the three UPR pathways in TMUV-infected BHK-21 cells. Our results showed that expression of glucose-related protein 78 (GRP78) and GRP94 was upregulated during the course of TMUV infection. We then demonstrated that TMUV activated the PERK pathway in the early stage of infection, resulting in upregulation of ATF4, GADD34 and CHOP, with CHOP induction leading to caspase-3 activation. We also found the IRE1 pathway to be activated, leading to splicing of X box binding protein 1 (XBP1) mRNA and enhanced expression of p58IPK. Finally, we observed increased expression of ATF6 and activity of ER stress-response elements, suggesting stimulation of the ATF6 pathway. In addition, ATF6 pathway activation correlated with the induction of downstream chaperones calnexin, calreticulin, ERp57 and PDI. UPR activity was also observed by the marked elevation in GRP78 and sXBP1 levels in TMUV-infected DF-1 cells. CONCLUSIONS: This is the first report that TMUV infection-induced ER stress activates three branches of the UPR, and these results lay the foundation for elucidating the pathogenesis of TMUV and understanding the inherent mechanism of TMUV infection as well as the host response.
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Infecciones por Flavivirus/metabolismo , Flavivirus/metabolismo , Respuesta de Proteína Desplegada , Animales , Western Blotting , Caspasa 1/metabolismo , Línea Celular , Pollos/virología , Cricetinae/virología , Retículo Endoplásmico/metabolismo , Retículo Endoplásmico/virología , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal , eIF-2 Quinasa/metabolismoRESUMEN
BACKGROUND: Tembusu virus is a newly emerging flavivirus that caused egg-drop syndrome in ducks in China. TMUV envelope protein is a major structural protein locates at the surface of tembusu virus particle. During tembusu virus infection, envelope protein plays a pivotal role in induction of neutralizing antibody. However, B cell epitopes within envelope protein have not been well studied. METHOD: A series of 13 peptides derived from E protein of tembusu virus were synthesized and screened by Dot blot with tembusu virus-positive duck serum. Potential B-cell epitopes were respectively fused with GST tag and expressed in E. coli. The immunogenicity and protective efficiency of epitopes were assessed in ducks. RESULTS: Dot blot assay identified the peptides P21 (amino acids 301-329), P23 (amino acids 369-387), P27 (amino acids 464-471) and P28 (amino acids 482-496) as potential B-cell epitopes within the envelope protein of tembusu virus. Immunization of prokaryotically expressed epitopes elicited specific antibodies in ducks and the specific antibody elicited by P21, P27 and P28 could neutralized tembusu virus. In addition, protective test suggested that P21 and P27 could completely protect immunized ducks from TMUV challenge. CONCLUSION: Four potential B cell epiotpes within tembusu virus envelope protein were identified and analyzed in vitro and in vivo. It was demonstrated that two of them (P21 and P27) could elicit neutralizing antibodies in ducks and offer complete protection against tembusu virus challenge. This findings will contribute to the development of epitope vaccine for tembusu virus prevention.
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Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Epítopos de Linfocito B/inmunología , Flavivirus/inmunología , Proteínas del Envoltorio Viral/inmunología , Animales , China , Patos , Infecciones por Flavivirus/inmunología , Infecciones por Flavivirus/veterinaria , Infecciones por Flavivirus/virología , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/virologíaRESUMEN
Newly emerging tembusu virus (TMUV) is a severe threat to poultry industry and causes huge economic losses. Humoral and cell-mediated immunity are both play vital roles in TMUV infection. Up to now, there has been no report on identification of T cell epitopes of the TMUV. In this work, we identified T cell epitopes within TMUV envelope (E) protein using synthesized peptides predicted in silico. A total of ten peptides could stimulate TMUV-specific T cells in murine ELISPOT and duck lymphocyte proliferation assay. Subsequently, DNA vaccine containing these T cell epitopes was constructed (pVAX-T) and the expression of multiepitope protein was confirmed by transfection of BHK-21 cells in vitro. Ducks were administrated intramusclarly to evaluated the immunologic effect of pVAX-T. In ducks immunized with pVAX-T, antibody against TMUV was undetectable, but the expression level of cytokines (IL-2, IL-6, IFN-γ) was upregulated both in peripheral blood lymphocytes and spleen. Furthermore, TMUV challenge revealed that cell-mediated immune response sitmulated by pVAX-T contributed to protection against TMUV infection. The identification of these T cell epitopes will contribute to designing epitope vaccine for preventing infection of TMUV and possibly provide the basis for further studies on cell-mediate immune response activated by TMUV.