Transglutaminase 2 inhibits the proliferation of H1 subtype influenza virus in MDCK cells / 生物工程学报

Transglutaminase 2 (TGM2) is a ubiquitous multifunctional protein, which is related to the adhesion of different cells and tumor formation. Previous studies found that TGM2 is involved in the interaction between host cells and viruses, but the effect of TGM2 on the proliferation of influenza virus in cells has not been reported. To explore the effect of TGM2 during H1N1 subtype influenza virus infection, a stable MDCK cell line with TGM2 overexpression and a knockout cell line were constructed. The mRNA and protein expression levels of NP and NS1 as well as the virus titer were measured at 48 hours after pot-infection with H1N1 subtype influenza virus. The results showed that overexpression of TGM2 effectively inhibited the expression of NP and NS1 genes of H1N1 subtype influenza virus, while knockout of TGM2 up-regulated the expression of the NP and NS1 genes, and the expression of the NP at protein level was consistent with that at mRNA level. Virus proliferation curve showed that the titer of H1N1 subtype influenza virus decreased significantly upon TGM2 overexpression. On the contrary, the virus titer in TGM2 knockout cells reached the peak at 48 h, which further proved that TGM2 was involved in the inhibition of H1N1 subtype influenza virus proliferation in MDCK cells. By analyzing the expression of genes downstream of influenza virus response signaling pathway, we found that TGM2 may inhibit the proliferation of H1N1 subtype influenza virus by promoting the activation of JAK-STAT molecular pathway and inhibiting RIG-1 signaling pathway. The above findings are of great significance for revealing the mechanism underlying the interactions between host cells and virus and establishing a genetically engineering cell line for high-yield influenza vaccine production of influenza virus.

Molecular evolution of influenza A/H3N2 viruses HA and NA genes circulating in Shenzhen in 2017 / 中华疾病控制杂志

Objective To investigate the molecular evolution of the Hemagglutinin (HA) and Neuraminidase (NA) genes of influenza A/H3N2 viruses in Shenzhen in the first half of 2017, so as to provide scientific basis for predicating influenza epidemic and variation. Methods A total of 40 influenza A/H3N2 viruses strains were selected and the molecular phylogenetic trees were constructed by bioinformatics software DNAStar, MEGA 7.0, etc. Then, the genetic characteristics and variation of HA and NA genes along with corresponding amino acids were analyzed. Results The homology of Shenzhen isolates reached 97.8%-100.0%, which located in the human-derived branch of Asia and North America. Compared with the vaccine strains A/Switzerland/9715293/2013(H3N2) and A/Hong Kong 14801/2014(H3N2) recommended by world Health Oraganication (WHO), there was a higher sequence similarity. Compared with the vaccine strain, HA and NA proteins had a number of amino acid sites replaced, of which HA 6 antigen sites and 2 receptor binding sites change; NA had a mutation of D151N/G located in enzyme activity sites. Potential N-glycosylation sites for HA and NA also changed. Conclusions The influenza A/H3N2 viruses in Shenzhen in the first half of 2017 has not yet formed a new subtype in the epidemic. Currently, the recommended vaccine strains still have some protective effects on the population. The replacement mutation of multiple amino acids sites of HA and NA suggests that the dynamic monitoring of molecular level of influenza A/H3N2 viruses need to be strengthened.

Genetic evolution of HA and NA genes of H9N2 influenza viruses isolated in regions of Hunan Province, China, in 2015 / 生物工程学报

The high prevalence of influenza A virus is identified in Hunan Province because of the high density of poultry farms. To survey the variations of H9N2 subtype avian influenza virus in Hunan province, we analyzed HA and NA genes of 10 virus strains isolated from different areas of Hunan Province. All these strains belong to the Eurasian lineage, Y280-like sub-lineage. The cleavage sites in their HA genes were all RSSR↓GLT, corresponding to the feature of low pathogenic AIV. All strains had an L (Leu) at the site 234 in the HA genes, indicating the ability of binding with the SAα-2,6 receptor. NA gene stalk deletions at aa 63-65 were also detected from all the isolates, indicating a possibility of increased virus replication in mammals. Our findings suggest that more attention should be paid to the surveillance of H9N2 influenza virus and its direction of reassortment.

Development and verification of reference nucleic acid materials of H9N2 influenza viruses by real-time RT-PCR / 生物工程学报

The HA gene of H9N2 influenza virus (A/chicken/Hunan/04.14 (H9N2)) was amplified and sequenced. The RNA was synthesized by in vitro transcription. The RNA transcription solutions were diluted to 10⁹ copies/μL using the RNA storage solution. The aliquoted RNA solutions were used to evaluate the homogeneity and stability. The results were determined by the average value obtained from four independent laboratories. Furthermore, the fluorescence quantitative RT-PCR method was also developed to verify the detection accuracy of clinical samples. The detection limit of this method is approximately 10 copies. Taken together, the RNA transcription solution established in our study can used as positive standard reference for rapid detection of H9N2 influenza virus.

Phylogeographical characterization of H5N8 viruses isolated from poultry and wild birds during 2014–2016 in South Korea

During 2014–2016 HPAI outbreak in South Korea, H5N8 viruses have been mostly isolated in western areas of the country, which provide wintering habitats for wild birds and have a high density of poultry. Analysis of a total of 101 Korean isolates revealed that primitive H5N8 viruses (C0 group) have evolved into multiple genetic subgroups appearing from various epidemiological sources, namely, the viruses circulating in poultry farms (C1 and C5) and those reintroduced by migratory birds in late 2014 (C2 and C4). No C3 groups were detected. The results may explain the possible reasons of the recent long-term persistence of H5N8 viruses in South Korea, and help to develop the effective measures in controlling HPAI viruses.

Relacionamento entre bases de dados para vigilância da pandemia de influenza A(H1N1)pdm09, Brasil, 2009-2010 / Database linkage for surveillance of the influenza A(H1N1)pdm09 pandemic in Brazil, 2009-2010 / Relación entre bases de datos para la vigilancia de la pandemia de gripe A(H1N1)pdm09, Brasil, 2009-2010

Resumo: O objetivo deste estudo foi o de descrever, com base no relacionamento entre os sistemas de informação SINAN (Sistema de Informação de Agravos de Notificação) e SIM (Sistema de Informações sobre Mortalidade), o perfil epidemiológico dos casos notificados de influenza por novo subtipo viral que evoluíram para óbito, durante a pandemia da doença. Foram utilizados dados secundários de ambos os sistemas referentes aos anos de 2009 e 2010. O relacionamento identificou 5.973 óbitos de casos notificados como influenza pandêmica. Destes, 2.170 (36,33%) haviam sido classificados no SINAN como confirmados para a enfermidade; 215 (3,6%), como infecção por outro agente infeccioso; e 3.340 (55,92%), como descartados. Após o relacionamento, alguns casos, que, no SINAN, foram encerrados com evolução para óbito por influenza (n = 658) ou óbito por outras causas (n = 847), não foram encontrados no SIM. O relacionamento entre os bancos de dados pode aprimorar o sistema de vigilância e o dimensionamento da morbimortalidade. Recomendamos o fortalecimento da vigilância da influenza no país com o uso do relacionamento entre os sistemas de informação do Ministério da Saúde.

Abstract: Based on database linkage, the objective of this study was to describe the epidemiological profile of notified cases and deaths from the new viral subtype of influenza during the influenza pandemic. Secondary data were used from the SINAN (Information System for Notifiable Diseases) and SIM (Mortality Information System) for the years 2009 and 2010. Linkage identified 5,973 deaths of cases notified as pandemic influenza. Of these, 2,170 (36.33%) had been classified in the SINAN as confirmed pandemic influenza, 215 (3.6%) as due to other infectious agents, and 3,340 (55.92%) as ruled out. After linkage, some cases in the SINAN database that were closed as death from influenza (n = 658) or death from other causes (n = 847) could not be located in the SIM database. Database linkage can improve the surveillance system and monitoring of morbidity and mortality. We recommend strengthening influenza surveillance in Brazil using linkage of Ministry of Health databases.

Resumen: El objetivo de este estudio fue el de describir, a partir de la relación entre los sistemas de información, el perfil epidemiológico de los casos notificados y que evolucionaron hacia el óbito por gripe, debido a un nuevo subtipo viral durante la pandemia de gripe. Se utilizaron datos secundarios, años 2009 y 2010, del Sistema de Información sobre Enfermedades de Notificación Obligatoria (SINAN) y Sistema de Información sobre Mortalidad (SIM). La relación identificó 5.973 óbitos de casos notificados como gripe pandémica. De esos, 2.170 (36,33%) habían sido clasificados en el SINAN y confirmados como gripe pandémica, 215 (3,6%) como infección por otro agente infeccioso y 3.340 (55,92%) como descartados. Tras la relación, algunos casos en el SINAN que fueron cerrados con la evolución, donde el óbito por gripe (n = 658) u óbito por otras causas (n = 847) no se encontraron en el banco del SIM. La relación entre los bancos de datos puede perfeccionar el sistema de vigilancia y el dimensionamiento de la morbimortalidad. Recomendamos el fortalecimiento de la vigilancia de la gripe en el país con el uso de la relación entre los sistemas de información del Ministerio de la Salud.

Manifestaciones clínicas y radiológicas de infección respiratoria por virus de influenza A H1N1 / Influenza A H1N1 virus respiratory infection: Clinical and radiological manifestations

Entre junio de 2009 y agosto de 2010 la Organización Mundial de la Salud (OMS) declaró una pandemia por el virus de infl uenza AH1N1. Para junio 2010 se habían confi rmado en Colombia 3.572 casos de infección respiratoria por el virus de infl uenza AH1N1 con una mortalidad de 239 pacientes. Objetivos: Describir las manifestaciones radiológicas de un grupo de 38 pacientes con diagnóstico confirmado de infección respiratoria por influenza A(H1N1) que requirieron hospitalización. Correlacionar las alteraciones radiológicas con la presentación clínica de los pacientes estudiados en la serie. Metodología: Análisis retrospectivo de historias clínicas y estudios de imágenes de una cohorte de 38 pacientes con diagnóstico confirmado de infección por influenza A (H1N1) hospitalizados en el Hospital Universitario Mayor - Méderi en Bogotá entre junio de 2009 y marzo de 2010. Los pacientes fueron divididos en dos grupos de acuerdo a la necesidad de soporte ventilatorio durante la hospitalización. Los estudios de imágenes fueron revisados en consenso por dos radiólogos con experiencia en radiología torácica. Resultados: De las 38 radiografías de tórax analizadas, 23 (60%) fueron normales. En las radiografías anormales (40% de los casos), las alteraciones más importantes fueron consolidación y vidrio esmerilado. En el grupo que requirió ventilación mecánica, todas las radiografías fueron anormales. Conclusiones: En nuestra serie, los hallazgos en los estudios de imágenes se correlacionaron con la severidad del cuadro clínico. En los pacientes que no requirieron ventilación mecánica, la radiografía de tórax fue normal en un 60%. Todos los pacientes que necesitaron soporte ventilatorio tenían alteraciones radiológicas al ingreso. En los pacientes que requirieron ventilación mecánica, la alteración radiológica predominante fue consolidación de predominio basal.

Between June 2009 and August 2010, the World Health Organization (WHO) declared a pandemic of the influenza H1N1 virus. Until June 2010, there were 3,572 confirmed cases of influenza AH1N1 virus respiratory infection in Colombia, with 239 deaths. Objectives: To describe the radiological studies of a group of 38 patients with a confirmed influenza A(H1N1) respiratory infection diagnosis who required hospitalization. The radiology results were correlated with clinical symptoms. Methodology: Medical records and image studies retrospective analysis of a 38 patient cohort with confirmed influenza A H1N1 infection diagnosis, who were hospitalized at the Universitario Mayor - Méderi Hospital in Bogota, Colombia between June 2009 and March 2010. Patients were divided into two groups according to the need for ventilatory support during hospitalization. The image studies were reviewed by two radiologists with thoracic radiology experience. Results: Of 38 chest radiographs analyzed, 23 (60%) were normal. Of the 40% abnormal radiographs, the findings were consolidation and ground glass images. In the group requiring mechanical ventilation, all radiographs were abnormal. Conclusions: In our series, the image study findings were correlated with the severity of the clinical symptoms. Among the patients requiring mechanical ventilation, the thoracic radiography was normal in 79% of the cases. All patients who required mechanical ventilation had radiological alterations at admission. The most common radiographic finding in the group of patients who required mechanical ventilation was basal parenchymal consolidation.

Abibliometric analysis of the international literatures on avian influenza / 第二军医大学学报

Objective To conduct a bibliometric analysis of international scientific literatures on research of avian influenza. Methods We performed a search in the Web of Science (WoS) database and analyzed the relevant records with Thomson Data Analyzer (TDA) and citation trees. Results Due to the rapid growth in publications by the United States and China, the number of publications on research of avian influenza has increased remarkably since 2005. The publication of Japan and Netherlands were of high quality due to support of international research programs. The researches about H5N1 virus mutation by the United States, Japan and Netherlands were the typical achievement of the area but also triggered arguments. Conclusion More international efforts arewarranted on research of H7N9 and other influenza viruses.

Evolutionary analysis of neuraminidase gene of the novel avian influenza virus A/H7N9 / 第二军医大学学报

Objective To investigate the evolutionary characteristics and important amino acid sites of the neuraminidase (NA) gene of the novel influenza virus A/H7N9 in 2013 epidemic. Methods The NA gene sequences of influenza virus A N9 subtype of different times and areaswere downloaded from the database of The National Center for Biotechnology Information (NCBI) and The Global Initiative on Sharing All Influenza Data (GISAID). MEGA 5. 05 and BioEdit softwares were used for phylogenetic tree construction and nucleotide/protein sequence analysis. Results The NA gene sequence of the novel influenza virus A/H7N9 in 2013 shared a 96% similarity with that of the H11N9 avian strain found in Czech Republic in 2010. There were 5 amino acid deletions in this novel influenza virus,and one of the new strains had a variation in potential enzymatic active sites. Conclusion The NA gene of this 2013 novel influenza virus might originate from the avian H11N9 strains detected in Czech Republic. The deletion of amino acid might result in human infection and high fatality rate.

Phylogenetic analysis of hemagglutinin (HA) gene of the novel avian influenza virus A/H7n9 / 第二军医大学学报

Objective To investigate the evolution and variations in coding amino acids of hemagglutinin (HA) gene of the novel avian influenza virus H7N9 in 2013 epidemic. Methods The HA gene sequences of influenza virus H7N9, H7N2, H7N3 and H7N7 subtypeswere downloaded from the database of The National Center for Biotechnology Information (NCBI) and The Global Initiative on Sharing All Influenza Data (GISAID). MEGA 5. 05 software was used for sequence analysis and N- J method was used for constructing the phylogenetic trees. The amino acid sequences at the receptor binding sites, glycosylation sites, and cleavage siteswas aligned and analyzed. Results The HA genes this novel A/H7N9 virus in 2013 shared a 95. 3%- 95. 6% similarity with JQ906573. 1| Zhejiang (H7N3 virus) isolated in 2011. The most important variation in this novel H7N9 isolates was found at the receptor binding site: Q226L. The 5 glycosylation sites were highly conservative. One basic amino acid (R) at the HA cleavage sites, located between aa339 and aa340, was also found in this novel isolate. Conclusion The HA gene of this novel H7N9 isolate might originate from H7 subtypes carried by birds in China. Thebinding site change caused by Q226L variation might be responsible for human infection of this novel H7N9 isolate.

Novel avian influenza A H7N9 virus? viral feature and potential threat to human health / 第二军医大学学报

H7N9 virus is a novel avian-origin virus. The hemagglutinin (HA) and neuraminidase (NA) of the virus play key roles in the interspecies transmission, viral replication and pathogenicity. One of significant characters of H7N9 is that it has no noticeable pathogenicity among poultry, but is highly pathogenic for human being and is associated with high mortality. H7 subtype avian virus can be compatible with different NA subtypes, and has caused many infection events in human being. It can be predicted that the influence ofH7 subtype avian influenza A virus will persist and lead to serious public health problem, and therefore deserves more attention. Establishment of prevetion and control network can help to reduce the threat of H7N9 virus to human health.

Epidemiological characteristics and control strategies of avian influenza A (H7N9) / 第二军医大学学报

A novel avian influenza was discovered in Mainland China in March 2013, and the virus was identified as avian influenza A (H7N9)-anew virus that has not been reported previously before. Further research showed that the virus was probably a combination of three different subtypes of influenza A virus. By May 31, a total of 131 confirmed cases have been reported in China, including 39 deaths. Shanghai reported 33 confirmed cases, with the onset of 29 cases found before closing the live poultry markets by the municipal government on April 6. The onsets of the rest 4 cases were all found during the first incubation period after the closure. We found that 66. 7% (22/33) of the confirmed cases in Shanghai were above 60 years of age, and of the 15 deaths, 80% (12/15) were aged above 60 years old. It was also noted that 90. 9% (30/33) of the confirmed cases had an exposure history to susceptible animals orenvironmental circumstances. The cases appeared to be sporadic; although there were two family clusters, no evidence of human-to-human transmission has been found so far. Shanghai municipal government activated the Flu Pandemic Preparedness and Response Plan (Level IH ) onApril 2, 2013, timely after the first few cases was identified. The rapid responses of public health emergencies included citywide suspending of live poultry markets, health education, and risk communication; the epidemic was controlled effectively and timely. In this paper we analyzed the pros and cons of our prevention and control strategies, hoping to provide reference for future epidemics.

Prevention and control of the novel H7N9 influenza in 2013: Public health issue and coping strategies / 第二军医大学学报

In March 2013, death caused by infection with the novel H7N9 avian influenza virus was firstly reported in China. In addition to the viral evolution factors such as gene recombination and variation in key amino acid sites, social factors also contribute to human infection of the deadly virus. By now China still needs a standardized poultry breeding process, an orderly poultry trade market, a strong health awareness among poultry-related workers, and a strong sel--protection awareness among all citizens. Social factors may increase the chance of influenza virus transmission from birds to humans via increasing close contact. Therefore, a close joint effort of related government departments, including the agriculture, forestry, and medication, is needed for effective control and surveillance of H7N9 epidemic. The health protection and risk awareness should be upgraded among the citizens through health education. Meanwhile, research and development of influenza vaccine should be accelerated based on the surveillance data of the influenza virus evolution. Public health prophylaxis based on social influencing factors should be important in reducing the incidence of avian flu infection in human.

Novel Influenza A (H1N1)-Associated Acute Necrotizing Encephalopathy: A Case Report

Several cases of acute necrotizing encephalopathy (ANE) with influenza A (H1N1) have been reported to date. The prognosis of ANE associated with H1N1 is variable; some cases resulted in severe neurologic complication, whereas other cases were fatal. Reports mostly focused on the diagnosis of ANE with H1N1 infection, rather than functional recovery. We report a case of ANE with H1N1 infection in a 4-year-old Korean girl who rapidly developed fever, seizure, and altered mentality, as well as had neurologic sequelae of ataxia, intentional tremor, strabismus, and dysarthria. Brain magnetic resonance imaging showed lesions in the bilateral thalami, pons, and left basal ganglia. To our knowledge, this is the first report of ANE caused by H1N1 infection and its long-term functional recovery in Korea.

Evaluation of pregnancy as a risk factor in the outcomes of influenza A (H1N1)/2009 in women of childbearing age / Avaliação da gestação como fator de risco nos desfechos da influenza A (H1N1)/2009 em mulheres em idade fértil

The aim of this study was to verify whether pregnancy was a risk factor for death in influenza A (H1N1)/2009 infection. We compared the case-fatality rates for pandemic influenza among non-pregnant women of childbearing age and pregnant women, besides investigating other factors that differentiated the groups in relation to the outcomes. The data were collected from the National Information System on Diseases of Notification (SINAN), of the Ministry of Health. The study used cases with laboratory confirmation and included 1,861 women from 10 to 49 years of age, of whom 352 were pregnant. The case-fatality rate during the 2009 pandemic was 4.5 percent for pregnant women and 6.4 percent for non-pregnant women (p = 0.197). Logistic regression did not show an association between pregnancy and death (OR = 0.7; 95 percentCI: 0.41-1.21). However, there were significant differences between the two groups in relation to mean age, treatment with oseltamivir, schooling, and presence of other risk factors.

O objetivo deste estudo foi verificar se a gestação esteve associada como fator de risco para o óbito na infecção por Influenza A (H1N1)/2009. Comparou-se a letalidade da influenza pandêmica entre mulheres em idade fértil e gestantes, realizando ainda a busca por outros fatores que diferenciem os grupos em relação aos desfechos. Os dados foram coletados no Sistema de Informação de Agravos de Notificação (SINAN), do Ministério da Saúde. Foram utilizados os casos confirmados laboratorialmente, sendo incluídas 1.861 mulheres com idades entre 10 e 49 anos, das quais 352 eram gestantes. A taxa de letalidade observada durante a pandemia de 2009 foi de 4,5 por cento para as gestantes e 6,4 por cento para as não gestantes (p = 0,197). O resultado da regressão logística não evidenciou associação entre a presença de gestação e o óbito (OR = 0,7; IC95 por cento: 0,41-1,21). No entanto, houve diferenças significativas entre os dois grupos em relação à idade média, ao tratamento com oseltamivir, à escolaridade e à presença de outros fatores de risco.

Recurrent Plastic Bronchitis in a Child with 2009 Influenza A (H1N1) and Influenza B Virus Infection

Plastic bronchitis is an uncommon disorder characterized by the formation of bronchial casts. It is associated with congenital heart disease or pulmonary disease. In children with underlying conditions such as allergy or asthma, influenza can cause severe plastic bronchitis resulting in respiratory failure. A review of the literature showed nine cases of plastic bronchitis with H1N1 including this case. We report a case of a child with recurrent plastic bronchitis with eosinophilic cast associated with influenza B infection, who had recovered from plastic bronchitis associated with an influenza A (H1N1) virus infection 5 months previously. To the best of our knowledge, this is the first case of recurrent plastic bronchitis related to influenza viral infection. If patients with influenza virus infection manifest acute respiratory distress with total lung atelectasis, clinicians should consider plastic bronchitis and early bronchoscopy should be intervened. In addition, management for underlying disease may prevent from recurrence of plastic bronchitis.

Recombination analysis of full-length genomic sequences of novel influenza virus A/H1N1 in 2009 pandemic / 第二军医大学学报

Objective: To analyze the recombination of full-length genomic sequences of novel influenza virus A/H1N1 in 2009 pandemic. Methods: The full-length sequences of the novel A/H1N1 and reference sequences were downloaded from NCBI database. MEGA4.0 software was used to connect, align sequences, and analyze the similarity between the full-length sequences of the novel virus and each of the reference strains. Recombination was analyzed by Simplot software (version 3.5.1). Results: Simplot analysis indicated that the PB1 genes (polymerase B1, PB1) of the novel A/H1N1 viruses might evolve from human H3N2 virus (identity: 93.7%); the PB2 genes (polymerase B2, PB2) and the PA genes (polymerase A, PA) might evolve from avian H5N1 viruses (identity: 89.0%, 89.9%, respectively); the HA genes (hemagglutinin, HA), the NP genes (nucleoprotein, NP) and the NS genes (non-structural protein, NS) showed high similarities with those of swine H1N1 viruses isolated in North America (identity: 91.7%, 93.1%, and 93.1%, respectively); and the NA genes (neuraminidase, NA) and the MP genes (matrix protein, MP) might evolve from European swine H1N1 viruses (identity: 90.5%, 95.5%, respectively). The full-length sequence of the novel A/H1N1 viruses had a highest similarities with swine H1N1 viruses isolated in North America (identity: 83.9%). Conclusion: The novel influenza virus A/H1N1 is a recombinant virus evolving from human H3N2 viruses, swine H1N1 from North America, swine H1N1 from Europe, and swine H5N1 from Asia.

Evolutionary characteristics of polymerase PA, PB1, and PB2 genes of novel influenza virus A/H1N1 in 2009 pandemic / 第二军医大学学报

Objective: To elucidate the evolutionary characteristics of polymerase PA, PB1, and PB2 genes of the novel influenza virus A/H1N1 in 2009 pandemic. Methods: The sequences of the PA, PB1, and PB2 genes of the novel H1N1 strains in 2009 pandemic, and the reference sequences of human, swine, and avian influenza viruses isolated during different years at different locations were retrieved from NCBI. Molecular Evolutionary Genetics Analysis version 4.0 (MEGA4.0) software was employed to align and blunt nucleotide sequences, construct phylogenetic tree, deduce and align PB2 protein sequences, and the results were compared between the novel A/H1N1 and each of the reference strains. Results: The sequences of the PA, PB1, and PB2 genes of 2009 novel A/H1N1 strains isolated from different locations shared a high homology and clustered in a unique new clade, and were close to the swine influenza viruses. The PA, PB1, and PB2 genes of the novel H1N1 viruses had a high similarity with the corresponding sequences of a human H1N1 strain isolated in Iowa State of USA in 2005 (A/Iowa/CEID23/2005/H1N1). Alignments of the deduced protein sequences showed that the 627th amino acid of PB2 of the novel H1N1 strains and A/Iowa/CEID23/2005/H1N1 were glutamic acid (Glu), which was the same as that in the avian influenza virus in Iowa State of USA in 2005 (DQ889682), and was different from those of the reference sequences of human A/H1N1 strains isolated from 1918 to 2008, which were lysine (Lys). Conclusion: The 2009 novel A/H1N1 virus might be originated from the human A/H1N1 strains isolated in 2005 in Iowa State of America (A/Iowa/CEID23/2005/H1N1), and the polymerase gene of the novel H1N1 virus might re-assort with avian A influenza virus.

Genetic characteristics and deduced protein variation of nonstructural protein of novel influenza virus A/H1N1 in 2009 pandemic / 第二军医大学学报

Objective: To elucidate the genetic characteristics and deduced protein variation of nonstructural protein (NS) gene of the novel influenza virus A/H1N1 in 2009 pandemic. Methods: The sequence of NS gene of A/H1N1 viruses isolated in North America, Europe, and Asia during 1930-2009 were downloaded from NCBI database. MEGA4.0 software and NJ method were used for sequence alignment, protein sequence alignment, and the phylogenetic tree construction. Results: The NS genes of novel influenza virus A/H1N1 in 2009 pandemic were originated from A/swine/H1N1 virus of 2005-2007; they shared a high homology of 97.5%-97.6%. There was an obvious evolutionary relationship between the NS genes of novel A/H1N1 virus and those of the influenza A/swine/H1N1 viruses isolated in North America from 1930 to 2007. No obvious changes were found in the amino acid sites for the antagonistic function of NS1 against the host antiviral capacity among these viruses. Conclusion: The NS gene of novel influenza virus A/H1N1 in 2009 pandemic might evolve from swine A/H1N1 influenza viruses isolated in the United States. The antagonistic function of NS1 against the host antiviral capacity is not changed.

Molecular evolutionary analysis of matrix protein and nucleoprotein genes of novel influenza virus A/H1N1 in 2009 pandemic / 第二军医大学学报

Objective: To analyze evolutionary characteristics of the matrix protein (M) and nucleoprotein (NP) genes of influenza virus A/H1N1 in 2009 pandemic. Methods: The M and NP genes of A/H1N1 viruses were downloaded from NCBI database. MEGA4.0 software and NJ method were used for sequence alignment, protein sequence alignment, and the phylogenetic tree construction. Meanwhile, Epi Info software was used to analyze the linear trend of evolutionary distance of the M and NP genes of human H1N1 strains isolated during 1918 to 2009. Results: The M and NP gene sequences were similar among the novel A/H1N1 viruses, but different from those of the previous influenza H1N1 viruses. Using reference sequences of human H1N1 strains isolated during 1918 to 2008, we found that changes in evolutionary distances of the M genes between novel A/H1N1 strains and each of the reference A/H1N1 strains increased with increasing year intervals (Ptrend = 0.001). Compared with the amino acid sequence of M2 protein of reference human A/H1N1 virus strains isolated during 1918 to 2008, the novel A/H1N1 viruses had the amino acid substitutions at 6 sites: 11, 43, 54, 57, 77, and 78. Compared with swine and avian A/H1N1, the novel A/H1N1 virus only had the amino acid substitutions at 43 and 77. Conclusion: The NP gene of novel A/H1N1 virus, which is routinely considered as a conserved sequence, is different from those of the previously isolated human H1N1 influenza viruses; the related mechanisms and consequences on viral activity remain to be elucidated. The substitution to threonine at 11 and 43 amino acids of M2 protein might contribute to amantadine resistance of the novel H1N1 virus pandemic in 2009.