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1.
Environ Pollut ; 290: 118032, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34467886

RESUMO

The annual mean PM2.5 mass concentration has decreased because of the stringent emission controls implemented in Beijing, China in recent years, whereas the nitrate NO3- mass fraction in PM2.5 increases gradually. Low-visibility events occur frequently even though PM2.5 pollution has been mitigated significantly, with the daily mean PM2.5 mass concentration mostly less than 75 µg/m3. In this study, the non-linear relationship was analyzed between atmospheric visibility and PM2.5 based on chemical composition from a two-year field observation. Our results showed that NO3- became the main constituent of PM2.5, especially during the haze pollution episodes. A localized parameterization scheme was proposed between the atmospheric extinction coefficient (σext) and major chemical constituents of PM2.5 by multiple linear regression (MLR). The contribution of NO3- to σext increased with increasing air pollution, and NO3- became the most important contributor for PM2.5 above 75 µg/m3. The visibility decreased with increasing NO3- mass fraction for the same PM2.5 mass concentration when PM2.5 was above 20 µg/m3. The hygroscopicity of PM2.5 increased with increasing mass fraction of hygroscopic NO3-. These results stressed the importance of reducing particulate NO3- and its precursors (for instance, NH3) through effective emission control measures as well as the tightening of PM2.5 standards to further improve air quality and visibility in Beijing.

2.
Science ; 373(6557): 918-922, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34413236

RESUMO

Zoonotic avian influenza A virus (IAV) infections are rare. Sustained transmission of these IAVs between humans has not been observed, suggesting a role for host genes. We used whole-genome sequencing to compare avian IAV H7N9 patients with healthy controls and observed a strong association between H7N9 infection and rare, heterozygous single-nucleotide variants in the MX1 gene. MX1 codes for myxovirus resistance protein A (MxA), an interferon-induced antiviral guanosine triphosphatase known to control IAV infections in transgenic mice. Most of the MxA variants identified lost the ability to inhibit avian IAVs, including H7N9, in transfected human cell lines. Nearly all of the inactive MxA variants exerted a dominant-negative effect on the antiviral function of wild-type MxA, suggesting an MxA null phenotype in heterozygous carriers. Our study provides genetic evidence for a crucial role of the MX1-based antiviral defense in controlling zoonotic IAV infections in humans.


Assuntos
Subtipo H7N9 do Vírus da Influenza A , Influenza Humana/genética , Influenza Humana/virologia , Proteínas de Resistência a Myxovirus/genética , Doenças dos Trabalhadores Agrícolas/genética , Doenças dos Trabalhadores Agrícolas/virologia , Animais , Linhagem Celular , Predisposição Genética para Doença , Variação Genética , Heterozigoto , Humanos , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Vírus da Influenza A/fisiologia , Mutação de Sentido Incorreto , Proteínas de Resistência a Myxovirus/química , Proteínas de Resistência a Myxovirus/metabolismo , Aves Domésticas , Zoonoses Virais , Sequenciamento Completo do Genoma
3.
Sci Total Environ ; 795: 148809, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34328915

RESUMO

Chassis dynamometer experiments were conducted to investigate the effect of vehicle speed and usage of ethanol-blended gasoline (E10) on formation and evolution of gasoline vehicular secondary organic aerosol (SOA) using a Gothenburg Potential Aerosol Mass (Go: PAM) reactor. The SOA forms rapidly, and its concentration exceeds that of primary organic aerosol (POA) at an equivalent photochemical age (EPA) of ~1 day. The particle effective densities grow from 0.62 ± 0.02 g cm-3 to 1.43 ± 0.07 g cm-3 with increased hydroxyl radical (OH) exposure. The maximum SOA production under idling conditions (4259-7394 mg kg-fuel-1) is ~20 times greater than under cruising conditions. There was no statistical difference between SOA formation from pure gasoline and its formation from E10. The slopes in Van Krevelen diagram indicate that the formation pathways of bulk SOA includes the addition of both alcohol/peroxide functional groups and carboxylic acid formation from fragmentation. A closure estimation of SOA based on bottom-up and top-down methods shows that only 16%-38% of the measured SOA can be explained by the oxidation of measured volatile organic compounds (VOCs), suggesting the existence of missing precursors, e.g. unmeasured VOCs and probably semivolatile or intermediate volatile organic compounds (S/IVOCs). Our results suggest that applying parameters obtained from unified driving cycles to model SOA concentrations may lead to large discrepancies between modeled and ambient vehicular SOA. No reduction in vehicular `SOA production is realized by replacing normal gasoline with E10.


Assuntos
Poluentes Atmosféricos , Gasolina , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Gasolina/análise , Emissões de Veículos/análise
4.
Sci Total Environ ; 786: 147418, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-33975110

RESUMO

Links between the optical properties and chemical compositions of brown carbon (BrC) are poorly understood because of the complexity of BrC chromophores. We conducted field studies simultaneously at both vehicle-influenced site and biomass burning-affected site in China in polluted winter. The chemical compositions and light absorption values of functionalized aromatic compounds, including phenyl aldehyde, phenyl acid, and nitroaromatic compounds, were measured. P-phthalic acid, nitrophenols and nitrocatechols were dominant BrC species, accounting for over 50% of the concentration of identified chromophores. Nitrophenols and nitrocatechols contributed more than 50% of the identified BrC absorbance between 300 and 400 nm. Oxidation of biomass burning-related products (e.g., pyrocatechol and methylcatechols) and anthropogenic volatile organic compounds (e.g., benzene and toluene) generated similar BrC chromophores, implying that these functionalized aromatic compounds play an important role in both environments. Compared with the biomass burning-affected site (22%), functionalized aromatic compounds at vehicle-influenced site accounted for a higher percentage of BrC absorption (25%). This research improves our understanding of the links between optical properties and composition of BrC, and the difference between BrC chromophores from BB-influenced area and vehicle-affected area under polluted atmospheric conditions.

5.
Sci Total Environ ; 771: 144948, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33736152

RESUMO

The variations of non-refractory submicron aerosol (NR-PM1) were characterized using an high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and other online instruments measurements sampled at an urban site in Shanghai from 2016 to 2017. Spring (from 18 May to 4 June 2017), summer (from 23 August to 10 September 2017) and winter (from 28 November 2016 to 23 January 2017) seasons were chosen for detail investigating the seasonal variations in the aerosol chemical characteristics. The average PM1 (NR-PM1 + BC) mass concentration showed little difference in the three seasons in Shanghai. The average mass concentrations of total PM1 during spring, summer, and winter observations in Shanghai were 23.9 ± 20.7 µg/m3, 28.5 ± 17.6 µg/m3, and 31.9 ± 22.7 µg/m3, respectively. The seasonal difference on chemical compositions was more significant between them. Organic aerosol (OA) and sulfate were dominant contributor of PM1 in summer, whereas OA and nitrate primarily contribution to the increase of PM1 mass loading in spring and winter. As an abundant component in PM1 (accounting for 39%-49%), OA were resolved into two primary organic aerosol (POA) factors and two secondary aerosol (SOA) factors by using positive matrix factorization (PMF), of which OA was overwhelmingly dominated by the SOA (50-60%) across the three seasons in Shanghai. Correlation analysis with relative humidity and odd oxygen indicated that aqueous-phase processing and played an important role in more aged SOA formation in summer and winter. In spring, both aqueous-phase and photochemical processing contributed significantly to fresh SOA formation. Our results suggest the significant role of secondary particles in PM pollution in Shanghai and highlight the importance of control measures for reducing emissions of gaseous precursors, especially need to consider seasonal characteristics.

6.
Virol Sin ; 36(1): 43-51, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32638231

RESUMO

Eurasian avian-like H1N1 (EA H1N1) swine influenza virus (SIV) outside European countries was first detected in Hong Kong Special Administrative Region (Hong Kong, SAR) of China in 2001. Afterwards, EA H1N1 SIVs have become predominant in pig population in this country. However, the epidemiology and genotypic diversity of EA H1N1 SIVs in China are still unknown. Here, we collected the EA H1N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features, and key molecular markers of these EA H1N1 SIVs. Our results showed that EA H1N1 SIVs distributed in nineteen provinces/municipalities of China. After a long-time evolution and transmission, EA H1N1 SIVs were continuously reassorted with other co-circulated influenza viruses, including 2009 pandemic H1N1 (A(H1N1)pdm09), and triple reassortment H1N2 (TR H1N2) influenza viruses, generated 11 genotypes. Genotype 3 and 5, both of which were the reassortments among EA H1N1, A(H1N1)pdm09 and TR H1N2 viruses with different origins of M genes, have become predominant in pig population. Furthermore, key molecular signatures were identified in EA H1N1 SIVs. Our study has drawn a genotypic diversity image of EA H1N1 viruses, and could help to evaluate the potential risk of EA H1N1 for pandemic preparedness and response.

7.
J Epidemiol Glob Health ; 11(1): 26-33, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32959611

RESUMO

BACKGROUND: Restricted outdoor activities and online learning during COVID-19 pandemic may pose threats on the physical and mental health of Chinese adolescents in middle schools. The study was to explore the relationship of Physical Activity (PA) and Sedentary Time (SED) with mood states among Chinese adolescents during the pandemic. METHODS: A total of 4898 adolescents (16.3 ± 1.3 years old) from 49 middle schools in 13 urban and rural areas in Yan'an, China volunteered to participate in this study and completed online questionnaires. International Physical Activity Questionnaire (IPAQ) were used to measure PA and SED, and Profile of Mood States were used to evaluate mood states. We used Mann-Whitney U-test and Kruskal-Wallis test to assess differences in PA and SED in different sex and grade group, respectively. Mixed linear regression was used to analyze the relationship between PA/SED and mood states. RESULTS: Participants in our study accumulated 23.4 ± 52.5 min of moderate-to-vigorous PA and 363.6 ± 148.4 min of SED per day. The mood states of boys were better than that of girls (p < 0.01). The mood states of the students in Senior High School Grade 3 were at the highest level of mood disturbance. Higher levels of PA were significantly associated with lower levels of total mood disturbance in this population (High PA group according to IPAQ: B = -3.22, SE = 0.40, p < 0.001; Moderate: B = -1.47, SE = 0.37, p < 0.001, compared to Low PA group). CONCLUSION: Chinese adolescents maintained a sedentary lifestyle during the COVID-19 pandemic. Girls and students in Grade 3 Senior High School had higher level of mood disturbance. More PA was associate with improving mood state among adolescents in the pandemic. The present study may assist policymakers and healthcare professionals understand PA and mood states of Chinese adolescents during the epidemic and take targeted actions in case of emergencies in future.


Assuntos
Sintomas Afetivos , COVID-19 , Educação à Distância/métodos , Exercício Físico/psicologia , Saúde Mental/estatística & dados numéricos , Estudantes , Adolescente , Comportamento do Adolescente/fisiologia , Comportamento do Adolescente/psicologia , Afeto/fisiologia , Sintomas Afetivos/diagnóstico , Sintomas Afetivos/etiologia , Sintomas Afetivos/prevenção & controle , COVID-19/epidemiologia , COVID-19/prevenção & controle , COVID-19/psicologia , China/epidemiologia , Feminino , Humanos , Controle de Infecções/métodos , Masculino , Saúde da População Rural , SARS-CoV-2 , Comportamento Sedentário , Fatores Sexuais , Estudantes/psicologia , Estudantes/estatística & dados numéricos , Inquéritos e Questionários , Saúde da População Urbana
8.
Artigo em Inglês | MEDLINE | ID: mdl-31964651

RESUMO

Influenza is a global challenge, and future pandemics of influenza are inevitable. One of the lessons learned from past pandemics is that all pandemic influenza viruses characterized to date possess viral genes originating from avian influenza viruses (AIVs). During the past decades, a wide range of AIVs have overcome the species barrier and infected humans with different clinical manifestations ranging from mild illness to severe disease and even death. Understanding the mechanisms of infection in the context of clinical outcomes, the mechanism of interspecies transmission, and the molecular determinants that confer interspecies transmission is important for pandemic preparedness. Here, we summarize the epidemiology, virology, and pathogenicity of human infections with AIVs to further our understanding of interspecies transmission.

9.
Environ Pollut ; 270: 116209, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33360069

RESUMO

In the present work, we propose a novel algorithm to determine the scattering coefficient of OA by evaluating the relationships of the MSEs for primary organic aerosol (POA) and secondary organic aerosol (SOA) with their mass concentrations at three distinct sites, i.e. an urban site, a rural site, and a background site in China. Our results showed that the MSEs for POA and SOA increased rapidly as a function of mass concentration in low mass loading. While the increasing rate declined after a threshold of mass loading of 50 µg/m3 for POA, and 15 µg/m3 for SOA, respectively. The dry scattering coefficients of submicron particles (PM1) were reconstructed based on the algorithm for POA and SOA scattering coefficient and further verified by using multi-site data. The calculated dry scattering coefficients using our reconstructing algorithm have good consistency with the measured ones, with the high correlation and small deviation in Shanghai (R2 = 0.98; deviations: 2.9%) and Dezhou (R2 = 0.90; deviations: 4.7%), indicating that our algorithms for OA and PM1 are applicable to predict the scattering coefficient of OA and Submicron particle (PM1) in China.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , Algoritmos , China , Tamanho da Partícula
10.
Artigo em Inglês | MEDLINE | ID: mdl-33096659

RESUMO

The COVID-19 epidemic adversely affects the lifestyle of people. This study aimed to examine the impacts of social isolation on physical activity (PA) levels and mood states of children and adolescents and to explore the correlation between them during the COVID-19 epidemic. A total of 9979 children and adolescents (11.63 ± 1.23 years old) from Yan'an, China volunteered to participate in this study and completed online questionnaires. PA and mood states were measured by International Physical Activity Questionnaire Short Form (IPAQ-SF) and Profile of Mood States (POMS), respectively. The results showed that the mean of students' moderate-to-vigorous PA (MVPA) was 23.19 min per day. The total mood disturbance in the moderate and high-level PA groups were significantly lower than those in the low-level PA group (p < 0.05). Additionally, boys and girls had significant differences in PA levels (p < 0.01), and the PA levels of students in different grades were also significantly different (p < 0.01). Meanwhile, boys' mood states were worse than girls'. The Grade 4 in primary schools had the worst mood states while Grade 5 had the best mood states. The results suggested that the MVPA of students has dropped badly, compared with the results of previous studies investigated in normal times. In addition, the PA level had a significantly positive impact on the mood states of children and adolescents during the COVID-19 epidemic. Sex and grades were factors which affected the PA levels and mood states. This study can help policymakers and healthcare professionals understand PA and mood states of Chinese children and adolescents during the epidemic. We should pay attention to the changes in PA levels and mood states of children and adolescents.


Assuntos
Infecções por Coronavirus/epidemiologia , Exercício Físico , Pneumonia Viral/epidemiologia , Isolamento Social , Adolescente , Betacoronavirus , COVID-19 , Criança , China/epidemiologia , Feminino , Humanos , Masculino , Pandemias , SARS-CoV-2
11.
Emerg Microbes Infect ; 9(1): 1853-1863, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32746754

RESUMO

Influenza B virus (IBV) is one of the most important human respiratory viruses: it causes approximately one-third of the global influenza-related disease burden each year. However, compared with the several pathogenicity-related molecular markers that have been identified for influenza A virus (IAV), little is known about potential IBV pathogenicity-related markers. Here, although the IBV strain B/Anhui-Tunxi/1528/2014 (AH1528/14) exhibited a more efficient replication ability in vitro and higher pathogenicity in vivo compared with IBV strain B/Anhui-Baohe/127/2015 (AH127/15), only three amino acids differences (HAA390E, NAN342D and PB1V212I) were observed among their full genomes. The contributions of each amino acid difference to the virus pathogenicity were further investigated. Compared with the wild type IBV virus rAH127, the recombinant virus harbouring a single substitution of HAA390E had a similar phenotype, whereas the recombinant virus harbouring PB1V212I replicated to a moderately higher titre in both MDCK cells and in mice. Notably, the virus harbouring NAN342D showed significantly better growth properties in MDCK cells and higher fatality rates in mice. In addition, the presence of NAN342D dramatically enhanced the viral neuraminidase activity. In conclusion, our study identified a novel IBV molecular marker, NAN342D, that could significantly increase the virulence of IBV in mice.


Assuntos
Vírus da Influenza B/patogenicidade , Neuraminidase/genética , Infecções por Orthomyxoviridae/patologia , Vírus Reordenados/patogenicidade , Proteínas Virais/genética , Sequência de Aminoácidos/genética , Animais , Linhagem Celular , Cães , Feminino , Genoma Viral/genética , Células HEK293 , Humanos , Vírus da Influenza B/genética , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/virologia , Vírus Reordenados/genética , Replicação Viral/genética
12.
BMC Geriatr ; 20(1): 257, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32723295

RESUMO

BACKGROUND: Many older adults in the U.S. do not achieve the recommended amount of physical activity (PA) to fully realize a myriad of health benefits. Adiposity is one of those important correlates of PA and sedentary behaviors. However, the full extent to which adiposity is associated with PA and stationary time (STA) is uncertain. Therefore, we examined the association of adiposity with objectively measured PA and STA in black and white older adults. METHODS: We conducted a cross-sectional study of older adults enrolled in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study 2003-2007 who participated in an ancillary accelerometer study 2009-2013. Assessment of body mass index (BMI) and waist circumference (WC) was completed during an in-home visit in the parent study. PA was measured by Actical™ accelerometers, which provided estimates of moderate-to-vigorous-intensity PA (MVPA), light-intensity PA (LPA), and STA for 4-7 consecutive days. Data from accelerometers were standardized to square root percentages of total wear time per day (SqrtMVPA%, SqrtLPA%, and SqrtSTA%). Interactions were tested for BMI and WC by race and sex, separately. RESULTS: Data were available for 7873 participants (69.8 ± 8.7 yr, 54.2% women, 31.5% African American). In mixed linear regression models, significant interactions existed in BMI by race and sex for the SqrtMVPA%, WC by race and sex for the SqrtMVPA% and the SqrtLPA% model(p < 0.05). No interaction was significant for the logistic model of meeting the PA guideline or not. In subgroup analyses, BMI was inversely associated with SqrtMVPA%, SqrtLPA%, and positively related to SqrtSTA% in black women, white men and white women after adjustments. Similar patterns were observed between WC and SqrtMVPA%, SqrtLPA%, and SqrtSTA% in all groups, respectively. However, BMI was not associated with SqrtMVPA% in black men. Those with higher BMI or WC were less likely to meet the PA guideline in all groups. CONCLUSIONS: Adiposity was inversely associated with higher levels of MVPA/LPA and positively associated with higher levels of STA among black and white older adults. Prevention efforts aimed at promoting weight control may be beneficial to prevent physical inactivity and sedentary lifestyle among older adults.


Assuntos
Adiposidade , Comportamento Sedentário , Acelerometria , Idoso , Índice de Massa Corporal , Estudos Transversais , Exercício Físico , Feminino , Humanos , Masculino
13.
Artigo em Inglês | MEDLINE | ID: mdl-32659921

RESUMO

This study was to investigate the association of built environment (BE) with physical activity (PA) and physical fitness of residents inside the city wall of Xi'an, one of the most historic cities in China. The cross-sectional study was conducted among 728 adults in this area. BE and PA were measured by Neighborhood Environment Walkability Scale and International Physical Activity Questionnaire, respectively. Body mass index (BMI), body fat percentage, blood pressure (BP), lung capacity, curl up, sit and reach, reaction time, balance, and grip strength were also measured. The results showed, for men, aesthetics was positively associated with total and leisure-time PA, and curl-up tests, respectively. Walking/cycling facilities were positively associated with leisure-time PA. Street connectivity was negatively associated with leisure-time PA and BMI. Residential density was positively correlated with BMI. Access to service was positively associated with lung capacity. Crime safety was negatively correlated with reaction time. For women, residential density was negatively associated with transportation PA and BP. Street connectivity was positively associated with curl-up test. The results suggest some BE attributes are positively related to PA and physical fitness in this population. Creating more PA-supportive BEs is recommended in this historic area along with urban conservation.


Assuntos
Ambiente Construído , Planejamento Ambiental , Exercício Físico , Aptidão Física , Adulto , China , Cidades , Estudos Transversais , Feminino , Humanos , Masculino , Características de Residência , Transportes , Caminhada
15.
J Virol ; 94(8)2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-31996432

RESUMO

Genetic reassortments occurred continuously among multiple subtypes or genotypes of influenza viruses prevalent in pigs. Of note, some reassortant viruses bearing the internal genes of the 2009 pandemic H1N1 (2009/H1N1) virus sporadically caused human infection, which highlights their potential threats to human public health. In this study, we performed phylogenetic analysis on swine influenza viruses (SIVs) circulating in Liaoning Province, China. A total of 22 viruses, including 18 H1N1 and 4 H1N2 viruses, were isolated from 5,750 nasal swabs collected from pigs in slaughterhouses from 2014 to 2016. H1N1 viruses formed four genotypes, which included Eurasian avian-like H1N1 (EA H1N1) and double/triple reassortant H1N1 derived from EA H1N1, 2009/H1N1, and triple reassortant H1N2 (TR H1N2) viruses. H1N1 SIVs with different genotypes and even those within the same genotypes represented different pathogenicities in mice. We further characterized two naturally isolated H1N1 SIVs that had similar viral genomes but differed substantially in their virulence in mice and found that a single amino acid at position 431 in the basic polymerase 2 (PB2) protein significantly affected the viral replication capacity and virulence of these two viruses. Taken together, our findings revealed the diverse genomic origins and virulence of the SIVs prevalent in Liaoning Province during 2014 to 2016, which highlights that continuous surveillance is essential to monitor the evolution of SIVs. We identified a naturally occurring amino acid mutation in the PB2 protein of H1N1 SIVs that impacts the viral replication and virulence in mice by altering the viral polymerase activity.IMPORTANCE The frequent reassortment among different influenza viruses in pigs adds complexity to the epidemiology of swine influenza. The diverse viral virulence phenotypes underline the need to investigate the possible genetic determinants for evaluating the pandemic potential to human public health. Here, we found that multiple genotypes of influenza viruses cocirculate in the swine population in Liaoning Province, China. Furthermore, we pinpointed a single amino acid at position 431 in the PB2 protein which plays a critical role in the virulence of H1N1 viruses in mice and found that the alteration of viral polymerase activities is the cause of the different virulence. Our study further indicated that the virulence of influenza virus is a polygenic trait, and the newly identified virulence-related residue in the PB2 provides important information for broadening knowledge on the genetic basis of viral virulence of influenza viruses.


Assuntos
Aminoácidos/genética , Genótipo , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Filogenia , Vírus Reordenados/genética , Doenças dos Suínos/virologia , Animais , China , Modelos Animais de Doenças , Feminino , Genes Virais/genética , Genoma Viral , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H1N2/genética , Cinética , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Análise de Sequência de Proteína , Suínos , Virulência/genética , Replicação Viral , Sequenciamento Completo do Genoma
16.
Emerg Microbes Infect ; 8(1): 989-999, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31267843

RESUMO

It has recently been proposed that the Eurasian avian-like H1N1 (EA H1N1) swine influenza virus (SIV) is one of the most likely zoonotic viruses to cause the next influenza pandemic. Two main genotypes EA H1N1 viruses have been recognized to be infected humans in China. Our study finds that one of the genotypes JS1-like viruses are avirulent in mice. However, the other are HuN-like viruses and are virulent in mice. The molecular mechanism underlying this difference shows that the NP gene determines the virulence of the EA H1N1 viruses in mice. In addition, a single substitution, Q357K, in the NP protein of the EA H1N1 viruses alters the virulence phenotype. This substitution is a typical human signature marker, which is prevalent in human viruses but rarely detected in avian influenza viruses. The NP-Q357K substitution is readily to be occurred when avian influenza viruses circulate in pigs, and may facilitate their infection of humans and allow viruses also carrying NP-357K to circulate in humans. Our study demonstrates that the substitution Q357K in the NP protein plays a key role in the virulence phenotype of EA H1N1 SIVs, and provides important information for evaluating the pandemic risk of field influenza strains.


Assuntos
Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/virologia , Mutação de Sentido Incorreto , Infecções por Orthomyxoviridae/veterinária , Proteínas de Ligação a RNA/genética , Doenças dos Suínos/virologia , Proteínas do Core Viral/genética , Animais , China , Feminino , Genótipo , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Nucleocapsídeo , Infecções por Orthomyxoviridae/virologia , Filogenia , Proteínas de Ligação a RNA/metabolismo , Suínos , Proteínas do Core Viral/metabolismo , Virulência , Replicação Viral
17.
Virol J ; 16(1): 87, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31266524

RESUMO

BACKGROUND: Human infection with avian influenza H7N9 virus was first reported in 2013. Since the fifth epidemic, a highly pathogenic avian influenza (HPAI) H7N9 virus has emerged and caused 33 human infections. Several potential NAI resistance sites have been found in human cases. However, the drug susceptibility and replication ability of HPAI H7N9 virus with such substitutions have not yet been studied. METHODS: Thirty-three HPAI H7N9 virus strains were isolated from human cases in China, and then sequences were analyzed to identify potential NAI resistance sites. Recombinant influenza viruses were generated to evaluate the effect of NA amino acid substitutions on NAI (oseltamivir or zanamivir) susceptibility and viral replication efficiency in MDCK cells. RESULTS: Four potential NAI resistance sites, R292 K, E119V, A246T or H274Y, were screened. All four substitutions conferred either reduced or highly reduced susceptibility to oseltamivir or zanamivir. 292 K not only highly reduced the susceptibility of HPAI H7N9 to oseltamivir but also induced an increase in the IC50 of zanamivir. 119 V or 274Y conferred reduced susceptibility of HPAI H7N9 to oseltamivir. Additionally, 246 T conferred reduced susceptibility to zanamivir. All tested NAI-resistant viruses were capable of replication in MDCK cells. The virus yields of rg006-NA292K were lower than those of rg006-NA292R at 24, 48, 72 and 96 h postinfection (P<0.05). Rg006-NA119V, rg006-NA246T or rg006-NA274Y showed comparable replication capacity to wild-type virus (except for rg006-NA274Y at 96 h, P<0.05). CONCLUSIONS: All 4 amino acid substitutions (R292 K, E119V, A246T or H274Y) in NA reduced the susceptibility of HPAI H7N9 to NAIs. The NAI-resistant mutations in HPAI H7N9, in most cases, did not reduce the replication ability of the virus in mammalian cells. Special attention needs to be paid to these mutations, and the development of new anti-H7N9 drugs is of great importance.


Assuntos
Antivirais/farmacologia , Inibidores Enzimáticos/farmacologia , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Humana/virologia , Replicação Viral/efeitos dos fármacos , Substituição de Aminoácidos , Animais , Galinhas , Cães , Farmacorresistência Viral/genética , Humanos , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Influenza Aviária , Células Madin Darby de Rim Canino , Neuraminidase/antagonistas & inibidores , Oseltamivir/farmacologia , Zanamivir/farmacologia
18.
Bioorg Med Chem ; 27(17): 3846-3852, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31324565

RESUMO

The stems of Dryopteris crassirhizoma, one of the main components of Lianhua-Qingwen Formula (LQF) was traditionally used for heat-clearing and detoxifying. Dryocrassin ABBA is a key antiviral component in the herbal medicine while the compound is hard to get in large amounts with the features of homologous compounds, polyphenol groups, and low contents. Therefore, the present work aims to seek influenza H7N9 virus inhibitors from natural source by synthesis of dryocrassin ABBA and its analogues. As a result, total synthesis of the compound was achieved in nine steps with an over-all yield of 4.6%. Neuraminidases (NAs) inhibitory activities of the synthesized product and its analogues were evaluated afterward. Comparing with the positive control, OSV (9.6 µM), it was very exciting that dryocrassin ABBA and its analogues (b5 and e2) showed better NAs inhibitory activity against Anhui H7N9 with IC50 values of 3.6 µM, 2.5 µM and 1.6 µM. For the highly resistant Shanghai N9, these compounds can also show medium inhibitory activities. Docking results indicated the direct interaction of synthesized 3 hits with the key K294 by hydrogen bonds, but no direct interaction of OSV with the key K294 was observed in Shanghai N9. This study suggested that dryocrassin ABBA and its analogues especially AB, which consisted of polyphenol groups may have beneficial effects on treating avian influenza H7N9 virus.


Assuntos
Antivirais/farmacologia , Compostos de Benzilideno/farmacologia , Cicloexanonas/farmacologia , Farmacorresistência Viral/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Neuraminidase/antagonistas & inibidores , Antivirais/síntese química , Antivirais/química , Compostos de Benzilideno/síntese química , Compostos de Benzilideno/química , Cicloexanonas/síntese química , Cicloexanonas/química , Relação Dose-Resposta a Droga , Dryopteris/química , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Subtipo H7N9 do Vírus da Influenza A/enzimologia , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Neuraminidase/metabolismo , Relação Estrutura-Atividade
19.
Environ Pollut ; 253: 439-448, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31325889

RESUMO

Ambient submicron particles (PM1) exert significant impacts on visibility degradation during severe pollution episodes of urban China. The U.S. IMPROVE algorithms are widely used for assessing the extinction effect of atmospheric aerosols, but only suitable for fine particulate matter. A proper algorithm for PM1 extinction estimation is lacking and becomes urgent, especially after the online measurement of PM1 species is routine by aerosol mass spectrometers. Here we conducted three-month in-situ measurements to explore mass scattering efficiencies (MSE) of PM1 major species at a supersite of eastern China. Results indicated that MSEs of ammonium sulfate and nitrate increase quickly and then keep stable with the mass accumulation, while those of organic matter keep at ∼5.5 m2/g but with a large vibration in the whole mass range. The algorithm for reconstructing PM1 dry scattering coefficient was derived from the integral of the variation patterns for the three PM1 species. The algorithm was then validated and compared with other empirical algorithms through separate field measurements. Good correlations between the reconstructed and measured dry scattering coefficient were observed with R square higher than 0.9 and slope of 1.01-1.05, indicating that the reconstructed algorithm can predict the dry scattering coefficient well based on PM1 chemical composition measurements in urban China. Our study is expected to provide observed insights on the variation of MSE in the wide mass range especially in the high region, as well as accurate formulas for ambient PM1 dry scattering apportionment.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Aerossóis/análise , Algoritmos , China , Espectrometria de Massas/métodos , Nitratos/análise , Óxidos de Nitrogênio , Tamanho da Partícula , Material Particulado/análise
20.
Influenza Other Respir Viruses ; 13(5): 496-503, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31187583

RESUMO

BACKGROUND: Highly pathogenic avian influenza (HPAI) A(H7N9) virus emerged and caused human infections during the 2016-2017 epidemic wave of influenza A(H7N9) viruses in China. We report a human infection with HPAI H7N9 virus and six environmental isolates in Fujian Province, China. METHODS: Environmental surveillance was conducted in live poultry markets and poultry farms in Fujian, China. Clinical and epidemiologic data and samples were collected. Real-time RT-PCRs were conducted for each sample, and H7-positive samples were isolated using embryonated chicken eggs. Full genomes of the isolates were obtained by next-generation sequencing. Phylogenetic analysis and antigenic analysis were conducted. RESULTS: A 59-year-old man who raised about 1000 ducks was identified as HPAI H7N9 infection. Six HPAI H7 viruses were isolated from environmental samples, including five H7N9 viruses and one H7N6 virus. Phylogenetic results showed the human and environmental viruses are highly genetically diverse and containing significantly different gene constellation from that of other HPAI H7N9 previously reported. The internal genes derived from H7N9/H9N2, H5N6, and the Eurasian wild-bird gene pool, indicating waterfowl-originated genotypes, have emerged in HPAI H7N9/N6 viruses and caused human infection. CONCLUSION: The new genotypes raise the concern that these HPAI H7 viruses might transmit back into migratory birds and spread to other countries as the HPAI H5Nx viruses. Considering their capability of causing severe infections in both human and poultry, the HPAI H7 viruses in this study pose a risk to public health and the poultry industry and highlight the importance of sustained surveillance of these viruses.


Assuntos
Patos/virologia , Genoma Viral , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Animais , China/epidemiologia , Epidemias , Monitoramento Epidemiológico , Humanos , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Masculino , Pessoa de Meia-Idade , Filogenia , Aves Domésticas/virologia , Doenças das Aves Domésticas/virologia , Saúde Pública
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