RESUMEN
Infrared evanescent wave sensing based on chalcogenide fiber is an emerging technology for qualitative and quantitative analysis of most organic compounds. Here, a tapered fiber sensor made from Ge10As30Se40Te20 glass fiber was reported. The fundamental modes and intensity of evanescent waves in fibers with different diameters were simulated with COMSOL. The 30 mm length tapered fiber sensors with different waist diameters, 110, 63, and 31 µm, were fabricated for ethanol detection. The sensor with a waist diameter of 31 µm has the highest sensitivity of 0.73 a.u./% and a limit of detection (LoD) of 0.195 vol.% for ethanol. Finally, this sensor has been used to analyze alcohols, including Chinese baijiu (Chinese distilled spirits), red wine, Shaoxing wine (Chinese rice wine), Rio cocktail, and Tsingtao beer. It is shown that the ethanol concentration is consistent with the nominal alcoholicity. Moreover, other components such as CO2 and maltose can be detected in Tsingtao beer, demonstrating the feasibility of its application in detecting food additives.
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Therapeutic antibodies-F(ab')2 obtained from hyperimmune equine plasma could treat emerging infectious diseases rapidly because of their high neutralization activity and high output. However, the small-sized F(ab')2 is rapidly eliminated by blood circulation. This study explored PEGylation strategies to maximize the half-life of equine anti-SARS-CoV-2 specific F(ab')2. Equine anti-SARS-CoV-2 specific F(ab')2 were combined with 10 KDa MAL-PEG-MAL in optimum conditions. Specifically, there were two strategies: Fab-PEG and Fab-PEG-Fab, F(ab')2 bind to a PEG or two PEG, respectively. A single ion exchange chromatography step accomplished the purification of the products. Finally, the affinity and neutralizing activity was evaluated by ELISA and pseudovirus neutralization assay, and ELISA detected the pharmacokinetic parameters. The results displayed that equine anti-SARS-CoV-2 specific F(ab')2 has high specificity. Furthermore, PEGylation F(ab')2-Fab-PEG-Fab had a longer half-life than specific F(ab')2. The serum half-life of Fab-PEG-Fab, Fab-PEG, and specific F(ab')2 were 71.41 h, 26.73 h, and 38.32 h, respectively. The half-life of Fab-PEG-Fab was approximately two times as long as the specific F(ab')2. Thus far, PEGylated F(ab')2 has been prepared with high safety, high specificity, and a longer half-life, which could be used as a potential treatment for COVID-19.
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COVID-19 , SARS-CoV-2 , Animales , Caballos , SARS-CoV-2/metabolismo , Semivida , Anticuerpos , Ensayo de Inmunoadsorción Enzimática , Fragmentos Fab de InmunoglobulinasRESUMEN
In this study, a ratiometric optical fiber dissolved oxygen sensor based on dynamic quenching of fluorescence from a ruthenium complex is reported. Tris(4,7-diphenyl-1,10-phenanthrolin) ruthenium(II) dichloride complex (Ru(dpp)32+) is used as an oxygen-sensitive dye, and semiconductor nanomaterial CdSe/ZnS quantum dots (QDs) are used as a reference dye by mixing the two substances and coating it on the plastic optical fiber end to form a composite sensitive film. The linear relationship between the relative fluorescence intensity of the ruthenium complex and the oxygen concentration is described using the Stern-Volmer equation, and the ruthenium complex doping concentration in the sol-gel film is tuned. The sensor is tested in gaseous oxygen and aqueous solution. The experimental results indicate that the measurement of dissolved oxygen has a lower sensitivity in an aqueous environment than in a gaseous environment. This is due to the uneven distribution of oxygen in aqueous solution and the low solubility of oxygen in water, which results in a small contact area between the ruthenium complex and oxygen in solution, leading to a less-severe fluorescence quenching effect than that in gaseous oxygen. In detecting dissolved oxygen, the sensor has a good linear Stern-Volmer calibration plot from 0 to 18.25 mg/L, the linearity can reach 99.62%, and the sensitivity can reach 0.0310/[O2] unit. The salinity stability, repeatability, and temperature characteristics of the sensor are characterized. The dissolved oxygen sensor investigated in this research could be used in various marine monitoring and environmental protection applications.
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Puntos Cuánticos , Rutenio , Fibras Ópticas , Oxígeno , Espectrometría de Fluorescencia/métodosRESUMEN
BACKGROUND: In 2011, a new influenza virus, named Influenza D Virus (IDV), was isolated from pigs, and then cattle, presenting influenza-like symptoms. IDV is one of the causative agents of Bovine Respiratory Disease (BRD), which causes high morbidity and mortality in feedlot cattle worldwide. To date, the molecular mechanisms of IDV pathogenicity are unknown. Recent IDV outbreaks in cattle, along with serological and genetic evidence of IDV infection in humans, have raised concerns regarding the zoonotic potential of this virus. Influenza virus polymerase is a determining factor of viral pathogenicity to mammals. METHODS: Here we take a prospective approach to this question by creating a random mutation library about PB2 subunit of the IDV viral polymerase to test which amino acid point mutations will increase viral polymerase activity, leading to increased pathogenicity of the virus. RESULTS: Our work shows some exact sites that could affect polymerase activities in influenza D viruses. For example, two single-site mutations, PB2-D533S and PB2-G603Y, can independently increase polymerase activity. The PB2-D533S mutation alone can increase the polymerase activity by 9.92 times, while the PB2-G603Y mutation increments the activity by 8.22 times. CONCLUSION: Taken together, our findings provide important insight into IDV replication fitness mediated by the PB2 protein, increasing our understanding of IDV replication and pathogenicity and facilitating future studies.
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Infecciones por Orthomyxoviridae , Orthomyxoviridae , Thogotovirus , Aminoácidos/genética , Animales , Bovinos , Mutación , Porcinos , Thogotovirus/genética , Replicación ViralRESUMEN
Ebola virus (EBOV) infections result in aggressive hemorrhagic fever in humans, with fatality rates reaching 90% and with no licensed specific therapeutics to treat ill patients. Advances over the past 5 years have firmly established monoclonal antibody (MAb)-based products as the most promising therapeutics for treating EBOV infections, but production is costly and quantities are limited; therefore, MAbs are not the best candidates for mass use in the case of an epidemic. To address this need, we generated EBOV-specific polyclonal F(ab')2 fragments from horses hyperimmunized with an EBOV vaccine. The F(ab')2 was found to potently neutralize West African and Central African EBOV in vitro Treatment of nonhuman primates (NHPs) with seven doses of 100 mg/kg F(ab')2 beginning 3 or 5 days postinfection (dpi) resulted in a 100% survival rate. Notably, NHPs for which treatment was initiated at 5 dpi were already highly viremic, with observable signs of EBOV disease, which demonstrated that F(ab')2 was still effective as a therapeutic agent even in symptomatic subjects. These results show that F(ab')2 should be advanced for clinical testing in preparation for future EBOV outbreaks and epidemics.IMPORTANCE EBOV is one of the deadliest viruses to humans. It has been over 40 years since EBOV was first reported, but no cure is available. Research breakthroughs over the past 5 years have shown that MAbs constitute an effective therapy for EBOV infections. However, MAbs are expensive and difficult to produce in large amounts and therefore may only play a limited role during an epidemic. A cheaper alternative is required, especially since EBOV is endemic in several third world countries with limited medical resources. Here, we used a standard protocol to produce large amounts of antiserum F(ab')2 fragments from horses vaccinated with an EBOV vaccine, and we tested the protectiveness in monkeys. We showed that F(ab')2 was effective in 100% of monkeys even after the animals were visibly ill with EBOV disease. Thus, F(ab')2 could be a very good option for large-scale treatments of patients and should be advanced to clinical testing.
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Anticuerpos Neutralizantes/inmunología , Vacunas contra el Virus del Ébola/inmunología , Ebolavirus/inmunología , Fiebre Hemorrágica Ebola/prevención & control , Fragmentos Fab de Inmunoglobulinas/inmunología , Macaca mulatta/virología , Animales , Anticuerpos Antivirales/inmunología , Fiebre Hemorrágica Ebola/inmunología , Fiebre Hemorrágica Ebola/veterinaria , Caballos/inmunología , Inmunización , Fragmentos Fab de Inmunoglobulinas/administración & dosificación , Inmunoterapia/métodosRESUMEN
BACKGROUND: Feline calicivirus (FCV) is a common and highly prevalent pathogen causing upper respiratory diseases in kittens and felines in recent years. Due to the substantial genetic variability of the viral genes, existing vaccines cannot provide complete protection. Therefore, research on FCV antiviral drugs has received much attention. RESULTS: In this study, we found that copper chloride had dose-dependent antiviral effects on FCV in F81 cells. We also found that the combination of copper chloride and ribavirin had a synergistic protective effect against FCV in F81 cells. In contrast, the combination of copper chloride and horse anti-FCV immunoglobulin F (ab')2 showed an antagonistic effect, likely because copper chloride has an effect on F (ab')2 immunoglobulin; however, further research is needed to clarify this supposition. CONCLUSIONS: In summary, we found that copper chloride had low cytotoxicity and significant antiviral effects on FCV in F81 cells, providing a new drug candidate for the prevention and treatment of FCV infection.
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Calicivirus Felino/efectos de los fármacos , Cobre/farmacología , Ribavirina/farmacología , Animales , Antivirales/farmacología , Infecciones por Caliciviridae/tratamiento farmacológico , Infecciones por Caliciviridae/veterinaria , Enfermedades de los Gatos/tratamiento farmacológico , Gatos , Línea Celular , Sinergismo Farmacológico , Técnicas In VitroRESUMEN
We previously obtained mouse-adapted variants of H1N2 avian influenza virus that contained PB2-L134H, PB2-I647L, PB2-D701N, HA-G228S, and M1-D231N mutations. Here, we analyzed the effects of these mutations on viral pathogenicity in a mammalian model. By evaluating the virulence of mouse-adapted H1N2 variants at different generations, we found that the PB2-D701N and HA-G228S mutations both contribute to the virulence of this virus in mammals. Furthermore, we found that the PB2-D701N and HA-G228S mutations both enhance the ability of the virus to replicate in vivo and in vitro and that the PB2-D701N substitution results in an expansion of viral tissue tropism. These results suggest that the PB2-D701N mutation and the HA-G228S mutation are the major mammalian determinants of H1N2 virus. These results help us to understand more about the mechanisms by which influenza viruses adapt to mammals, and monitoring of these mutations can be used in continuous influenza surveillance to assess the pandemic potential of avian influenza virus variants.
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Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H1N2 del Virus de la Influenza A/genética , Gripe Aviar/virología , Mutación/genética , Proteínas Virales/genética , Virulencia/genética , Adaptación Biológica/genética , Sustitución de Aminoácidos/genética , Animales , Aves , Línea Celular , Perros , Femenino , Células de Riñón Canino Madin Darby , Mamíferos/virología , Ratones , Ratones Endogámicos BALB C , Infecciones por Orthomyxoviridae/virología , Fenotipo , Replicación Viral/genéticaRESUMEN
Feline panleukopenia virus (FPV) infects cats and can be fatal to kittens. There is evidence that canine parvovirus originated from FPV, which makes FPV important in studies of the family Parvoviridae. In the present study, the entire genome of FPV strain HH-1/86 was converted into a full-length infectious clone (pFPV). The FPV strain HH-1/86 has a 5123-nt single stranded DNA genome with a Y-shaped inverted 3' terminal repeat (ITR) and a U-shaped inverted 5' ITR. Feline kidney cells (F81) were transfected with the pFPV clone which contained a genetic marker, and a rescued virus was obtained (rFPV). The rFPV was identified by its cytopathic effects, indirect immunofluorescence, growth curve analysis, western blot assay and hemagglutination, and was indistinguishable from the parent virus. The FPV infectious clone will facilitate the study of pathogenicity and viral replication of FPV and the inter-species transmission of parvoviruses.
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Virus de la Panleucopenia Felina/genética , Panleucopenia Felina/virología , Genética Inversa , Animales , Gatos , Clonación Molecular , ADN Viral , Marcadores Genéticos , Genoma Viral , Genómica/métodos , Hemaglutinación , Hemaglutininas Virales/metabolismo , Genética Inversa/métodos , Secuenciación Completa del GenomaRESUMEN
Japanese encephalitis virus SA14-14-2 (JEV SA14-14-2) is a widely used vaccine in China and other southeastern countries to prevent Japanese encephalitis in children. In this study, a stable infectious cDNA clone of JEV SA14-14-2 with a low copy number pACYC177 vector dependent on the T7 promoter and T7 terminator was developed. Two introns were inserted into the capsid gene and envelope gene of JEV cDNA for gene stability. Hepatitis delta virus ribozyme (HDVr) was engineered into the 3' UTR cDNA of JEV for authentic 3' UTR transcription. The rescued virus showed biological properties indistinguishable from those of the parent strain (JEV SA14-14-2). The establishment of a JEV SA14-14-2 reverse genetics system lays the foundation for the further development of other flavivirus vaccines and viral pathogenesis studies.
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Virus de la Encefalitis Japonesa (Especie)/genética , Genética Inversa/métodos , Línea Celular , ADN Complementario , ADN Viral , Virus de la Encefalitis Japonesa (Especie)/ultraestructura , Vectores Genéticos , Genoma Viral , Regiones Promotoras Genéticas , Secuenciación del ExomaRESUMEN
BACKGROUND: Marburg virus (MARV) causes severe haemorrhagic fever in humans and nonhuman primates and has a high mortality rate. However, effective drugs or licensed vaccines are not currently available to control the outbreak and spread of this disease. METHODS: In this study, we generated MARV virus-like particles (VLPs) by co-expressing the glycoprotein (GP) and matrix protein (VP40) using the baculovirus expression system. MARV VLPs and three adjuvants, Poria cocos polysaccharide (PCP-II), poly(I:C) and aluminium hydroxide, were evaluated after intramuscular vaccination in mice. RESULTS: Murine studies demonstrated that vaccination with the MARV VLPs induce neutralizing antibodies and cellar immune responses. MARV VLPs and the PCP-II adjuvant group resulted in high titres of MARV-specific antibodies, activated relatively higher numbers of B cells and T cells in peripheral blood mononuclear cells (PBMCs), and induced greater cytokine secretion from splenocytes than the other adjuvants. CONCLUSION: MARV VLPs with the PCP-II adjuvant may constitute an effective vaccination and PCP-II should be further investigated as a novel adjuvant.
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Glicoproteínas/inmunología , Enfermedad del Virus de Marburg/prevención & control , Marburgvirus/inmunología , Vacunas de Partículas Similares a Virus/inmunología , Proteínas de la Matriz Viral/inmunología , Vacunas Virales/inmunología , Adyuvantes Inmunológicos , Animales , Anticuerpos Antivirales/inmunología , Antígenos Virales/inmunología , Linfocitos B/inmunología , Citocinas/sangre , Citocinas/metabolismo , Expresión Génica , Glicoproteínas/genética , Inmunidad Celular , Marburgvirus/genética , Ratones , Células Sf9 , Linfocitos T/inmunología , Vacunas de Partículas Similares a Virus/genética , Vacunas de Partículas Similares a Virus/ultraestructura , Proteínas de la Matriz Viral/genética , Vacunas Virales/genéticaRESUMEN
Porcine epidemic diarrhea virus (PEDV), which causes 80-100% mortality in neonatal piglets, is one of the most devastating viral diseases affecting swine worldwide. To date, the lack of effective vaccines and drugs is the main problem preventing control of the global spread of PEDV. In this study, we produced PEDV virus-like particles (VLPs) composed of S, M, and E proteins with a baculovirus expression system and tested them via indirect immunofluorescence assay (IFA)and Western blot analysis. Electron microscopy showed that the morphological structure of the PEDV VLPs was similar to that of the protovirus. Microneutralization assays and ELISpot analysis demonstrated that PEDV VLPs induced highly specific antibody responses and Th2-mediated humoral immunity. As a result, the PEDV VLPs displayed excellent immunogenicity in mice. Therefore, a VLP-based vaccine has the potential to prevent PEDV infection.
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Infecciones por Coronavirus/veterinaria , Inmunidad Humoral , Virus de la Diarrea Epidémica Porcina/inmunología , Enfermedades de los Porcinos/inmunología , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/virología , Femenino , Ratones , Ratones Endogámicos BALB C , Virus de la Diarrea Epidémica Porcina/genética , Porcinos , Enfermedades de los Porcinos/prevención & control , Enfermedades de los Porcinos/virología , Vacunas Virales/administración & dosificación , Vacunas Virales/genética , Vacunas Virales/inmunologíaRESUMEN
Canine parvovirus (CPV) can cause severe disease in animals and continuously generates new variant and recombinant strains in dogs that have a strong impact on sanitation. It is therefore necessary to investigate epidemic CPV strains to improve our understanding of CPV transmission and epidemic behavior. However, most studies have focused on the analysis of VP2, and therefore, information about recombination and relationships between strains is still lacking. Here, 14 strains of CPV were isolated from domestic dogs suspected of hosting CPV between 2013 and 2014 in China. The complete NS1 and VP2 genes were sequenced and analyzed. The results suggest that the new CPV-2a and new CPV-2b types are the prevalent strains in China. In addition to a few mutations (residues 19, 544, 545, 572 and 583 of NS1 and residues 267, 370, 377 and 440 of VP2) that were preserved during transmission, new mutations (residues 60, 630 of NS1, and residues 21, 310 of VP2) were found in the isolated strains. A phylogenetic tree based on VP2 sequences illustrated that the new CPV-2a and new CPV-2b strains from China form single clusters that are distinct from lineages from other countries. Moreover, recombination between the new CPV-2a and new CPV-2b types was also identified in the isolated strains. Due to differences in selection pressures or recombination, there were a small number of inconsistencies between the phylogenetic trees for VP2 and NS1, which indicated that phylogenetic relationships based on VP2 might not be representative of those based on NS1. The data indicated that mutations and recombination are constantly occurring along with the spread of CPV in China.
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Enfermedades de los Perros/virología , Infecciones por Parvoviridae/veterinaria , Parvovirus Canino/genética , Parvovirus Canino/aislamiento & purificación , Animales , China/epidemiología , Análisis por Conglomerados , ADN Viral/química , ADN Viral/genética , Enfermedades de los Perros/epidemiología , Perros , Variación Genética , Epidemiología Molecular , Datos de Secuencia Molecular , Mutación , Infecciones por Parvoviridae/epidemiología , Infecciones por Parvoviridae/virología , Filogenia , Recombinación Genética , Análisis de Secuencia de ADN , Homología de Secuencia , Proteínas Virales/genéticaRESUMEN
Rabies virus infection is a major public health concern because of its wide host-interference spectrum and nearly 100 % lethality. However, the interactions between host and virus remain unclear. To decipher the authentic response in the central nervous system after rabies virus infection, a dynamic analysis of brain proteome alteration was performed. In this study, 104 significantly differentially expressed proteins were identified, and intermediate filament, interferon-inducible GTPases, and leucine-rich repeat-containing protein 16C were the three outstanding groups among these proteins. Interferon-inducible GTPases were prominent because of their strong upregulation. Moreover, quantitative real-time PCR showed distinct upregulation of interferon-inducible GTPases at the level of transcription. Several studies have shown that interferon-inducible GTPases are involved in many biological processes, such as viral infection, endoplasmic reticulum stress response, and autophagy. These findings indicate that interferon-inducible GTPases are likely to be a potential target involved in rabies pathogenesis or the antiviral process.
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GTP Fosfohidrolasas/fisiología , Interacciones Huésped-Patógeno/fisiología , Interferones/fisiología , Rabia/metabolismo , Animales , Química Encefálica , Femenino , GTP Fosfohidrolasas/análisis , Ratones , Ratones Endogámicos BALB C , Proteómica/métodos , Virus de la Rabia/fisiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Espectrometría de Masas en TándemRESUMEN
Ebola virus (species Zaire ebolavirus) (EBOV) is highly virulent in humans. The largest recorded outbreak of Ebola hemorrhagic fever in West Africa to date was caused by EBOV. Therefore, it is necessary to develop a detection method for this virus that can be easily distributed and implemented. In the current study, we developed a visual assay that can detect EBOV-associated nucleic acids. This assay combines reverse transcription loop-mediated isothermal amplification and nucleic acid strip detection (RT-LAMP-NAD). Nucleic acid amplification can be achieved in a one-step process at a constant temperature (58 °C, 35 min), and the amplified products can be visualized within 2-5 min using a nucleic acid strip detection device. The assay is capable of detecting 30 copies of artificial EBOV glycoprotein (GP) RNA and RNA encoding EBOV GP from 10(2) TCID50 recombinant viral particles per ml with high specificity. Overall, the RT-LAMP-NAD method is simple and has high sensitivity and specificity; therefore, it is especially suitable for the rapid detection of EBOV in African regions.
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Ebolavirus , Fiebre Hemorrágica Ebola/diagnóstico , Técnicas de Amplificación de Ácido Nucleico/métodos , Ebolavirus/genética , Humanos , ARN Viral/genética , ARN Viral/aislamiento & purificación , Transcripción Reversa , Sensibilidad y Especificidad , Alineación de SecuenciaRESUMEN
BACKGROUND: In 2008, an outbreak of canine distemper virus (CDV) infection in monkeys was reported in China. We isolated CDV strain (subsequently named Monkey-BJ01-DV) from lung tissue obtained from a rhesus monkey that died in this outbreak. We evaluated the ability of this virus on Vero cells expressing SLAM receptors from dog, monkey and human origin, and analyzed the H gene of Monkey-BJ01-DV with other strains. RESULTS: The Monkey-BJ01-DV isolate replicated to the highest titer on Vero cells expressing dog-origin SLAM (10(5.2±0.2) TCID50/ml) and monkey-origin SLAM (10(5.4±0.1) TCID50/ml), but achieved markedly lower titers on human-origin SLAM cells (10(3.3±0.3) TCID50/ml). Phylogenetic analysis of the full-length H gene showed that Monkey-BJ01-DV was highly related to other CDV strains obtained during recent CDV epidemics among species of the Canidae family in China, and these Monkey strains CDV (Monkey-BJ01-DV, CYN07-dV, Monkey-KM-01) possessed a number of amino acid specific substitutions (E276V, Q392R, D435Y and I542F) compared to the H protein of CDV epidemic in other animals at the same period. CONCLUSIONS: Our results suggested that the monkey origin-CDV-H protein could possess specific substitutions to adapt to the new host. Monkey-BJ01-DV can efficiently use monkey- and dog-origin SLAM to infect and replicate in host cells, but further adaptation may be required for efficient replication in host cells expressing the human SLAM receptor.
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Virus del Moquillo Canino/aislamiento & purificación , Virus del Moquillo Canino/fisiología , Enfermedades de los Monos/virología , Receptores de Superficie Celular/genética , Replicación Viral/fisiología , Animales , China , Chlorocebus aethiops/virología , Perros , Interacciones Huésped-Patógeno/genética , Humanos , Pulmón/virología , Células VeroRESUMEN
The worldwide circulation of H9N2 avian influenza virus in poultry, the greater than 2.3 % positive rate for anti-H9 antibodies in poultry-exposed workers, and several reports of human infection indicate that H9N2 virus is a potential threat to human health. Here, we found three mutations that conferred high virulence to H9N2 virus in mice after four passages. The PB2-E627K substitution rapidly appeared at the second passage and played a decisive role in virulence. Polymerase complexes possessing PB2-E627K displayed 16.1-fold higher viral polymerase activity when compared to the wild-type virus, which may account for enhanced virulence of this virus. The other two substitutions (HA-N313D and HA-N496S) enhanced binding to both α2,3-linked and α2,6-linked sialic acid receptors; however, the HA-N313D and N496S substitutions alone decreased the virulence of mouse-adapted virus. Furthermore, this mouse-adapted virus was still not transmissible among guinea pigs by direct contact (0/3 pairs). Our findings show that adaption in mice enhanced the viral polymerase activity and receptor-binding ability, which resulted in a virulent phenotype in mice but not a transmissible phenotype in guinea pigs, indicating that host factors play an important role in adaptive evolution of influenza in new hosts.
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Adaptación Biológica , Sustitución de Aminoácidos , Subtipo H9N2 del Virus de la Influenza A/aislamiento & purificación , Infecciones por Orthomyxoviridae/virología , ARN Polimerasa Dependiente del ARN/genética , Proteínas Virales/genética , Animales , Femenino , Cobayas , Subtipo H9N2 del Virus de la Influenza A/genética , Subtipo H9N2 del Virus de la Influenza A/crecimiento & desarrollo , Subtipo H9N2 del Virus de la Influenza A/fisiología , Ratones Endogámicos BALB C , Mutación Missense , Infecciones por Orthomyxoviridae/transmisión , ARN Polimerasa Dependiente del ARN/metabolismo , Pase Seriado , Proteínas Virales/metabolismo , Virulencia , Acoplamiento Viral , Replicación ViralRESUMEN
Rabies virus (RABV) can cause a fatal neurological disease in human and animals, and vaccines were generally applied for the immunoprophylaxis of rabies. Here, a recombinant viral vector carrying the exogenous gene expression component between phosphoprotein (P) and matrix protein (M) genes of RABV was constructed based on the vaccine strain SRV9 used in China. To develop a reverse genetic system, the full-length cDNA plasmids of SRV9 were constructed using the eukaryotic expression vector pCI or pcDNA3.1(+). However, recovery efficiency based on the pcDNA3.1 vector was significantly higher than that of the pCI vector. The exogenous gene expression component PE-PS-BsiWI-PmeI or PS-BsiWI-PmeI-PE was introduced in different locations between the P and M genes of SRV9. When the enhanced green fluorescent protein (eGFP) was used as a reporter gene, both locations could rescue recombinant RABV (rRABV) expressing eGFP with high efficiency. Characterization of rRABV expressing eGFP in vitro revealed that its growth was similar to that of the parental virus. Animal experiments showed that rRABV expressing eGFP could replicate and express eGFP in the brains of suckling mice. Furthermore, rRABV of SRV9 was nonpathogenic for 3-week-old mice and could be cleared from the central nervous system at 5 days post-inoculation. Our results showed that the recombinant SRV9 virus could be used as a useful viral vector for exogenous gene expression.
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Expresión Génica , Vectores Genéticos/genética , Proteínas Fluorescentes Verdes/genética , Vacunas Antirrábicas/genética , Virus de la Rabia/genética , Animales , Femenino , Vectores Genéticos/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Ratones , Ratones Endogámicos BALB C , Plásmidos/genética , Plásmidos/metabolismo , Vacunas Antirrábicas/metabolismo , Virus de la Rabia/metabolismo , Genética InversaRESUMEN
Two new coumarins, (E)-2-(4-hydroxy-3-methoxybenzylidene)-5-methoxy-2H-[1,4]dioxino[2,3-h]chromene-3,9-dione (indicumin E, 1) and 7-hydroxy-6,8-dimethoxy-3-(4'-hydroxy-3'-methoxyphenyl)-coumarin (2), together with two known coumarins isofraxidin (3) and fraxetin (4), were isolated from the Solanum indicum seeds. Their structures were established on the basis of 1D and 2D spectroscopic data. Compound 1 was the rarest coumarinolignoid known to date.
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Cumarinas/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Solanum/química , Cumarinas/química , Medicamentos Herbarios Chinos/química , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Semillas/químicaRESUMEN
The neural control of human quiet stance remains controversial, with classic views suggesting a limited role of the brain and recent findings conversely indicating direct cortical control of muscles during upright posture. Conceptual neural feedback control models have been proposed and tested against experimental evidence. The most renowned model is the continuous impedance control model. However, when time delays are included in this model to simulate neural transmission, the continuous controller becomes unstable. Another model, the intermittent control model, assumes that the central nervous system (CNS) activates muscles intermittently, and not continuously, to counteract gravitational torque. In this study, a delayed reinforcement learning algorithm was developed to seek optimal control policy to balance a one-segment inverted pendulum model representing the human body. According to this approach, there was no a-priori strategy imposed on the controller but rather the optimal strategy emerged from the reward-based learning. The simulation results indicated that the optimal neural controller exhibits intermittent, and not continuous, characteristics, in agreement with the possibility that the CNS intermittently provides neural feedback torque to maintain an upright posture.
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Postura , Humanos , Postura/fisiología , Refuerzo en Psicología , Aprendizaje , Factores de Tiempo , Modelos Biológicos , TorqueRESUMEN
Nipah virus (NiV) is a virulent zoonotic disease whose natural host is the fruit bat (Pteropus medius), which can coexist with and transmit the virus. Due to its high pathogenicity, wide host range, and pandemic potential, establishing a sensitive, specific, and rapid diagnostic method for NiV is key to preventing and controlling its spread and any outbreaks. Here, we established a luciferase immunosorbent assay (LISA) based on the NiV attachment glycoprotein (G) to detect NiV-specific immunoglobulin G by expressing a fusion protein of nanoluciferase (NanoLuc) and the target antigen. Sensitivity analysis was performed and compared to an indirect enzyme-linked immunosorbent assay (ELISA), and specificity and cross-reactivity assessments were performed using NiV-positive horse serum and Ebola virus-, Crimean-Congo hemorrhagic fever virus-, and West Nile virus-positive horse sera. The optimal structural domain for NiV detection was located within amino acids 176-602 of the NiV G protein head domain. Moreover, the LISA showed at least fourfold more sensitivity than the indirect ELISA, and the cross-reactivity results suggested that the LISA had good specificity and was capable of detecting NiV-specific immunoglobulin G in both mouse and horse serum. In conclusion, the establishment of a rapid, simple NiV LISA using the G protein head domain provides a resource for NiV monitoring.