Genetic and biological properties of H9N2 avian influenza viruses isolated in central China from2020 to 2022

The H9N2 subtype of avian influenza virus(AIV)is widely prevalent in poultry and wild birds globally,and has become the predominant subtype circulating in poultry in China.The H9N2 AIV can directly or indirectly(by serving as a"donor virus")infect humans,posing a significant threat to public health.Currently,there is a lack of in-depth research on the prevalence of H9N2 viruses in Shanxi Province,central China.In this study,we isolated 14 H9N2 AIVs from October 2020 to April 2022 in Shanxi Province,and genetic analysis revealed that these viruses belonged to 7 different genotypes.Our study on animals revealed that the H9N2 strains we identified displayed high transmission efficiency among chicken populations,and exhibited diverse replication abilities within these birds.These viruses could replicate efficiently in the lungs of mice,with one strain also demonstrating the capacity to reproduce in organs like the brain and kidneys.At the cellular level,the replication ability of different H9N2 strains was evaluated using plaque formation assays and multi-step growth curve assays,revealing significant differences in the replication and proliferation efficiency of the various H9N2 viruses at the cellular level.The antigenicity analysis suggested that these isolates could be classified into 2 separate antigenic clusters.Our research provides crucial data to help understand the prevalence and biological characteristics of H9N2 AIVs in central China.It also highlights the necessity of enhancing the surveillance of H9N2 AIVs.

Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system

H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

Dairy cows inoculated with highly pathogenic avian influenza virus H5N1

Highly pathogenic avian influenza(HPAI)H5N1 hemagglutinin clade 2.3.4.4b was detected in the United States in 2021.These HPAI viruses caused mortality events in poultry,wild birds,and wild mammals.On March 25,2024,HPAI H5N1 clade 2.3.4.4b was confirmed in a dairy cow in Texas in response to a multi-state investigation into milk production losses.1 Over 200 positive herds were identified in 14 U.S.states.The case description included reduced feed intake and rumen motility in lactating cows,decreased milk production,and thick yellow milk.2,3 The diagnostic investigation revealed viral RNA in milk and mammary tissue with alveolar epithelial degeneration and necrosis and positive immunoreactivity of glandular epithelium.A single transmission event,likely from birds,was followed by limited local transmission and onward horizontal transmission of H5N1 clade 2.3.4.4b genotype B3.13.4 We sought to experimentally reproduce infection with genotype B3.13 in Holstein yearling heifers and lactating cows.Heifers were inoculated by aerosol respiratory route and cows by intramammary route.Clinical disease was mild in heifers,but infection was confirmed by virus detection,lesions,and seroconversion.Clinical disease in lactating cows included decreased rumen motility,changes to milk appearance,and production losses.Infection was confirmed by high levels of viral RNA detected in milk,virus isolation,lesions in mammary tissue,and seroconversion.This study provides the foundation to investigate additional routes of infection,pathogenesis,transmission,and intervention strategies.

2022-2023年山东省A(H1N1)pdm09流感病毒HA、NA基因变异特征分析

目的 了解山东省2022-2023流感监测年度分离的A(H1N1)pdm09亚型流感病毒血凝素(hemagglutinin,HA)和神经氨酸酶(neuraminidase,NA)基因的变异特征,为流感的防控提供科学依据。方法 从流感监测网络实验室分离的流感毒株中按地市随机选取14株A(H1N1)pdm09亚型流感毒株,以WHO推荐的当季疫苗株为参考进行全基因组测序,并采用荧光法开展神经氨酸酶抑制(neuraminidase inhibition,NI)实验以评估药物敏感性。结果 山东省2022-2023年度分离的A(H1N1)pdm09流感病毒属于6B.1A分支中的5a.2a进化簇,核苷酸序列比对分析显示,HA和NA基因与2021-2023年度北半球疫苗株A/Victoria/2570/2019的亲缘关系较为接近,同源性分别为98.5%~98.7%和98.8%~99.1%。氨基酸序列分析显示,HA蛋白有20个位点发生了氨基酸序列变异,并发现1株病毒可能发生抗原漂移,有3株病毒发生了HA蛋白糖基化位点的缺失。NA酶相关重要位点未发生变异。NI实验显示,所测流感毒株均对抗流感病毒药物敏感。结论 所监测毒株与疫苗株整体同源性很高,但氨基酸存在一定程度变异,今后有必要持续开展流感病毒基因变异特征监测以了解流感流行的风险,以及评价基因变异对流感疫苗和治疗药物效果的影响。

2023年湖州市区pdm09 H1N1流感病毒NA基因特征分析

pdm09 H1N1流感病毒自2009年爆发引起全球大流行,目前已成为流感流行常见亚型之一[1]。该病毒包含由8个基因片段,其中神经氨酸酶(neuraminidase,NA)是嵌入流感病毒包膜表面的一种重要的功能糖蛋白[2]。主要负责成熟病毒从宿主细胞中释放,在感染下一个宿主细胞进行复制转录,最终使机体出现临床症状和体征[3]。

基于UPLC-Q-Exactive-Orbitrap-MS、网络药理学和实验验证探讨裸花紫珠抗H1N1活性成分及其作用机制

本实验首先对裸花紫珠的提取物进行萃取,得到不同的萃取部位,然后对各部位进行抗甲型流感病毒H1N1型(H1N1)活性筛选,确定裸花紫珠乙酸乙酯萃取部位(EACN)具有较好的体外抗H1N1的活性。采用超高效液相色谱-四级杆-静电场轨道阱联用(UPLC-Q-Exactive-Orbitrap-MS)技术对EACN进行定性分析。基于定性分析的结果,进一步使用数据挖掘和网络药理学,评估药物的活性成分、关键靶点和关键通路,最后使用H1N1感染BALB/c小鼠模型对预测结果进行验证。结果显示,在各个萃取部位中,乙酸乙酯部位体外抗H1N1效果最佳,半数抑制浓度(IC_(50))为51μg/mL,半数细胞毒浓度(CC_(50))为859.4μg/mL,选择指数(SI,CC_(50)/IC_(50))为16.85。从EACN中鉴定出34种化合物,在此基础上,利用网络药理学,筛选出和EACN抗H1N1相关的药物靶点67个,靶点共涉及生物过程491个,与抗H1N1相关的通路147个。H1N1感染BALB/c小鼠实验结果发现,EACN能改善H1N1感染引起的体重降低和肺指数的增加,降低小鼠肺组织的病毒载量,减轻小鼠肺组织的病理损伤,降低外周血血清中TNF-α、IFN-γ、IL-1β水平。实验结果提示EACN可能从直接抑制病毒、抗炎作用和免疫调节作用等多个途径发挥抗H1N1的作用。

壮宣饮通过调节p38MAPK信号介导的肠道菌群治疗小儿H1N1肺炎的机制

目的探究壮宣饮通过调节p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38 MAPK)信号介导的肠道菌群治疗小儿甲型流感病毒H1N1肺炎的机制。方法取BALB/c小鼠采用H1N1流感病毒尿囊液滴鼻法制备H1N1肺炎小鼠模型,随机分为5组:模型组,壮宣饮低、中、高剂量组,壮宣饮高剂量(28.66 g·kg^(-1))+茴香霉素(10 mg·kg^(-1))组。对照组采用同法滴入等体积无菌生理盐水。使用壮宣饮和茴香霉素分组处理后,测定各组小鼠肺系数并以HE染色检测其肺与大肠组织病理形态;以16SrRNA基因测序检测各组小鼠肠道菌群结构差异改变;以酶联免疫吸附法(ELASA)测定各组小鼠肺泡灌洗液(BALF)及大肠组织中炎症因子肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-4、IL-6、IL-1β水平;以蛋白免疫印迹法检测各组小鼠肺与大肠组织中p38 MAPK通路相关蛋白表达。结果与对照组比较,模型组小鼠肺与大肠组织发生明显病理损伤,肺系数,肺与大肠病理评分,ACE指数,Shannon指数,梭菌目丰度,肺泡灌洗液与大肠组织中TNF-α、IL-4、IL-6、IL-1β水平,肺与大肠组织p-p38 MAPK/p38 MAPK水平均升高(P<0.05);拟杆菌目丰度降低(P<0.05)。与模型组比较,壮宣饮低、中、高剂量组小鼠肺与大肠组织病理损伤均减轻,肺系数,肺与大肠病理评分,ACE指数,Shannon指数,梭菌目丰度,肺泡灌洗液与大肠组织TNF-α、IL-4、IL-6、IL-1β水平,肺与大肠组织p-p38 MAPK/p38 MAPK水平均降低(P<0.05),且均呈剂量依赖性(P<0.05)。拟杆菌目丰度均升高(P<0.05),与壮宣饮高剂量组比较,壮宣饮高剂量+茴香霉素组小鼠肺与大肠组织病理损伤加重,肺系数,肺与大肠病理评分,ACE指数,Shannon指数,梭菌目丰度,肺泡灌洗液与大肠组织TNF-α、IL-4、IL-6、IL-1β水平,肺与大肠组织p-p38 MAPK/p38 MAPK水平均升高(P<0.05);拟杆菌目丰度降低(P<0.05)。结论壮宣饮可通过抑制p38 MAPK信号激活而改善H1N1肺炎小鼠肠道菌群失衡,从而抑制小鼠炎症并减轻其肺与大肠组织损伤,对小儿H1N1肺炎起到治疗作用。

N6-methyladenosine methylation regulates the tumor microenvironment of Epstein-Barr virus-associated gastric cancer

BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric cancer(EBVaGC)is a distinctive molecular subtype of GC.We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.AIM To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.METHODS First,The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC(EBVnGC).Second,we identified Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional enrichment of m6A-related differentially expressed genes.We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment(TME).Finally,cell counting kit-8 cell proliferation test,transwell test,and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1(IGFBP1)in EBVaGC cell lines.RESULTS m6A methylation regulators were involved in the occurrence and development of EBVaGC.Compared with EBVnGC,the expression levels of m6A methylation regulators Wilms tumor 1-associated protein,RNA binding motif protein 15B,CBL proto-oncogene like 1,leucine rich pentatricopeptide repeat containing,heterogeneous nuclear ribonucleoprotein A2B1,IGFBP1,and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC(P<0.05).The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher(P=0.046).GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC.Compared with EBVnGC,the infiltration of activated CD4+T cells,activated CD8+T cells,monocytes,activated dendritic cells,and plasmacytoid dendritic cells were significantly upregulated in EBVaGC(P<0.001).In EBVaGC,the expression level of proinflammatory factors interleukin(IL)-17,IL-21,and interferon-γ and immunosuppressive factor IL-10 were significantly increased(P<0.05).In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line(SNU719)than in an EBVnGC cell line(AGS)(P<0.05).IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719.Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.CONCLUSION m6A regulators could remodel the TME of EBVaGC,which is classified as an immune-inflamed phenotype and referred to as a“hot”tumor.Among these regulators,we demonstrated that IGFBP1 affected proliferation,migration,and apoptosis.

Stop H5N1 influenza in US cattle now

The relentless march of a highly pathogenic avian influenza virus(HPAIV)strain,known as H5N1,to become an unprecedented panzootic continues unchecked.The leap of H5N1 clade 2.3.4.4b from Eurasia and Africa to North America in 2021 and its further spread to South America and the Antarctic have exposed new avian and mammalian populations to the virus and led to outbreaks on an unrivaled scale.The virus has infected wild birds across vast geographic regions and caused wildlife deaths in some of the world's most biodiverse ecosystems.

Antiviral activity of Basidiomycete mycelia against influenza type A(serotype H1N1) and herpes simplex virus type 2 in cell culture

In this study, we investigated the in vitro antiviral activity of the mycelia of higher mushrooms against influenza virus type A(serotype H1N1) and herpes simplex virus type 2(HSV-2), strain BH. All 10 investigated mushroom species inhibited the reproduction of influenza virus strain A/FM/1/47(H1N1) in MDCK cells reducing the infectious titer by 2.0–6.0 lg ID50. Four species, Pleurotus ostreatus, Fomes fomentarius, Auriporia aurea, and Trametes versicolor, were also determined to be effective against HSV-2 strain BH in RK-13 cells, with similar levels of inhibition as for influenza. For some of the investigated mushroom species—Pleurotus eryngii, Lyophyllum shimeji, and Flammulina velutipes—this is the first report of an anti-influenza effect. This study also reports the first data on the medicinal properties of A. aurea, including anti-influenza and antiherpetic activities. T. versicolor 353 mycelium was found to have a high therapeutic index(324.67), and may be a promising material for the pharmaceutical industry as an anti-influenza and antiherpetic agent with low toxicity. Mycelia with antiviral activity were obtained in our investigation by bioconversion of agricultural wastes(amaranth flour after CO2 extraction), which would reduce the cost of the final product and solve some ecological problems.

Molecular Characterization of Avian-like H1N1 Swine Influenza A Viruses Isolated in Eastern China, 2011

Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide： H1N1, H3N2, and H1N2. European avian-Hke H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3＇ end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation （S31N）, a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.

Influenza virus H1N1 induced apoptosis of mouse astrocytes and the effect on protein expression

Objective:To investigate the effects of influenza A virus H1N1 infection on the proliferation and apoptosis of mouse astrocytes cells and its protein expression.Methods:After mouse astrocytes was infected with purified influenza A virus H1N1 in vitro,viral integration and replication status of the cells were detected by RT-PCR assay,cell proliferation and apoptosis was determined by MTT method and flow cytometry,respectively.Associated protein expression was delected by Western blotting.Results:Agarose gel electrophoresis showed H1N1 virus can infect astrocytes and can be copied.MTT staining showed H1N1 virus infection can inhibit the proliferation of mouse astrocytes,which makes cell viability decreased significantly.Flow cytometry showed that the proportion of Annein V staining positive vascular endothelial cells in the influenza A virus group was significantly higher than that in the control group.Western blot analysis showed after24 h and 32 h of infection,there were cells caspase-3 protein and the expression of its active form(lysed caspase-3 protein)increased.The proportion of Bax/Bcl-2 also increased.Conclusions:Influenza A virus can infect human vascular endothelial cells and proliferation and it can induce apoptosis of endothelial cells.

Structure and Anti-influenza A(H1N1) Virus Activity of Three Polysaccharides from Eucheuma denticulatum

Three polysaccharides （EW, EH and EA） were prepared from a red alga Eucheuma denticulatum by sequential extraction with cold water, hot water and sodium hydroxide water solution. Their monosaccharide compositions, relative molecular mass and structural characterization were determined by gas chromatography, high performance liquid chromatography, fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods. EW was hybrid l/k/v-carrageenan （701/17k/13v-car- rabiose）, EH was mainly t-carrageenan, and EA was mainly α-1,4-Glucan （88%） but mixed with small amount of t-carrageenan （12%）. The relative molecular mass ofEW, EH and EA was 480, 580 and 510kDa, respectively. The anti-influenza A （H1N1） virus activity of these three polysaccharides was evaluated using the Madin-Darby canine kidney cells model. EW showed good anti-H1N1 virus activity, its ICso was 276.5 μg mL-1, and the inhibition rate to H1N1 virus was 52% when its concentration was 250 μgmL-1. The ICs0 of t-carrageenan EH was 366.4 μgmL1, whereas EA showed lower anti-H1N1 virus activity （IC50〉430μgmL-1）. Available data obtained give positive evidence that the hybrid carrageenan EW from Eueheuma denticulatum can be used as potential anti-H1N1 virus inhibitor in future.

Genetic Characteristics of 2009 Pandemic H1N1 Influenza A Viruses Isolated from China's Mainland

A total of 100 H1N1 flu real-time-PCR positive throat swabs collected from fever patients in Zhejiang, Hubei and Guangdong between June and November 2009, were provided by local CDC laboratories. After MDCK cell culture, 57 Influenza A Pandemic （H1N1） viruses were isolated and submitted for whole genome sequencing. A total of 39 HA sequences, 52 NA sequences, 36 PB2 sequences, 31 PB1 sequences, 40 PA sequences, 48 NP sequences, 51 MP sequences and 36 NS sequences were obtained, including 20 whole genome sequences. Sequence comparison revealed they shared a high degree of homology （96%-99%） with known epidemic strains （A/Califomia/04/2009（H1N1）. Phylogenetic analysis showed that although the sequences were highly conserved, they clustered into a small number of groups with only a few distinct strains. Site analysis revealed three substitutions at loop 220 （221-228） of the HA receptor binding site in the 39 HA sequences： A/Hubei/86/2009 PKVRDQEG→PKVRDQEA, A/Zhejiang/08/2009 PKVRDQEG→PKVRDQER, A/Hubei/75/2009 PKVRDQEG→PKVRDQGG, the A/Hubei/75/2009 was isolated from an acute case, while the other two were from patients with mild symptoms. Other key sites such as 119, 274, 292 and 294 amino acids of NA protein,627 of PB2 protein were conserved. Meanwhile, all the M2 protein sequences possessed the Ser32Asn mutation, suggesting that these viruses were resistant to adamantanes. Comparison of these sequences with other H1N1 viruses collected from the NCBI database provides insight into H1N1 transmission and circulation patterns.

Gene Expression Profiles Comparison between 2009 Pandemic and Seasonal H1N1 Influenza Viruses in A549 Cells

Objective To perform gene expression profiles comparison so that to identify and understand the potential differences in pathogenesis between the pandemic and seasonal A （H1N1） influenza viruses. Methods A549 cells were infected with A/California/07/09 （H1N1） and A/GuangdongBaoan/51/08 （H1N1） respectively at the same MOI of 2 and collected at 2, 4, 8, and 24 h post infection （p.i.）. Gene expression profiles of A549 cells were obtained using the 22 K Human Genome Oligo Array, and differentially expressed genes were analyzed at selected time points. Results Microarrays results indicated that both of the viruses suppressed host immune response related pathways including cytokine production while pandemic H1N1 virus displayed weaker suppression of host immune response than seasonal H1N1 virus. Observation on similar anti-apoptotic events such as activation of apoptosis inhibitor and down-regulation of key genes of apoptosis pathways in both infections showed that activities of promoting apoptosis were different in later stage of infection. Conclusion The immuno-suppression and anti-apoptosis events of pandemic H1N1 virus were similar to those seen by seasonal H1N1 virus. The pandemic H1N1 virus had an ability to inhibit biological pathways associated with cytokine responses, NK activation and macrophage recognition .

Identification of an H1N1 subtype of swine influenza virus and serological analysis

To investigate the epizootic of swine influenza virus(SIV),60 nasal swabs were collected from a clinical cases of pig farm in Tai’an City,Shandong Province of China in April 2017.SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced.An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1).Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch,seven genome segments belonged to avian-like H1N1 influenza virus lineage.The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G,which is a typical molecular biological characteristic.Five potential N-glycosylation sites(N14,N26,N277,N484 and N543) were found in the HA gene.To further investigate the epidemiology of SIV in this farm,the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens.The results showed that the total positive rate was 65.43%.The positive rates of single virus infection detected by EAH1N1,2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35,30.85 and 7.47%,respectively.The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm.These data provide evidence of an epizootic of SIV.

New mutational trends in the HA protein of 2009 H1N1 pandemic influenza virus from May 2010 to February 2011

As we enter the year of 2011, the 2009 H1N1 pandemic influenza virus is in the news again. At least 20 people have died of this virus in China since the beginning of 2011 and it is now the predominant flu strain in the country. Although this novel virus was quite stable during its run in the flu season of 2009-2010, a genetic variant of this virus was found in Singapore in early 2010, and then in Australia and New Zealand during their 2010 winter influenza season. Several critical mutations in the HA protein of this variant were uncovered in the strains collected from January 2010 to April 2010. Moreover, a structural homology model of HA from the A/Brisbane/10/2010(H1N1) strain was made based on the structure of A/California/04/2009 (H1N1). The purpose of this study was to investigate mutations in the HA protein of 2009 H1N1 from sequence data collected worldwide from May 2010 to February 2011. A fundamental problem in bioinformatics and biology is to find the similar gene sequences for a given gene sequence of interest. Here we proposed the inverse problem, i.e., finding the exemplars from a group of related gene sequences. With a clustering algorithm affinity propagation, six exemplars of the HA sequences were identified to represent six clusters. One of the clusters contained strain A/Brisbane/12/2010(H1N1) that only differed from A/Brisbane/10/2010 in the HA sequence at position 449. Based on the sequence identity of the six exemplars, nine mutations in HA were located that could be used to distinguish these six clusters. Finally, we discovered the change of correlation patterns for the HA and NA of 2009 H1N1 as a result of the HA receptor binding specificity switch, revealing the balanced interplay between these two surface proteins of the virus.

Integrated analysis of human influenza A(H1N1)virus infectionrelated genes to construct a suitable diagnostic model

The genome characteristics and structural functions of coding proteins correlate with the genetic diversity of the H1N1 virus,which aids in the understanding of its underlying pathogenic mechanism.In this study,analyses of the characteristic of the H1N1 virus infection-related genes,their biological functions,and infection-related reversal drugs were performed.Additionally,we used multi-dimensional bioinformatics analysis to identify the key genes and then used these to construct a diagnostic model for the H1N1 virus infection.There was a total of 169 differently expressed genes in the samples between 21 h before infection and 77 h after infection.They were used during the protein-protein interaction(PPI)analysis,and we obtained a total of 1725 interacting genes.Then,we performed a weighted gene co-expression network analysis(WGCNA)on these genes,and we identified three modules that showed significant potential for the diagnosis of the H1N1 virus infection.These modules contained 60 genes,and they were used to construct this diagnostic model,which showed an effective prediction value.Besides,these 60 genes were involved in the biological functions of this infectious virus,like the cellular response to type I interferon and in the negative regulation of the viral life cycle.However,20 genes showed an upregulated expression as the infection progressed.Other 36 upregulated genes were used to examine the relationship between genes,human influenza A virus,and infection-related reversal drugs.This study revealed numerous important reversal drug molecules on the H1N1 virus.They included rimantadine,interferons,and shikimic acid.Our study provided a novel method to analyze the characteristic of different genes and explore their corresponding biological function during the infection caused by the H1N1 virus.This diagnostic model,which comprises 60 genes,shows that a significant predictive value can be the potential biomarker for the diagnosis of the H1N1 virus infection.

Novel H1N1 influenza A virus infection in a patient with acute rejection after liver transplantation

BACKGROUND:The 2009 H1N1 influenza A virus was first identified in April 2009 and rapidly evolved into a pandemic. Recipients of solid-organ transplants have a higher risk for severe infection because of immunosuppression.There are limited reports of 2009 H1N1 influenza in liver transplant recipients,especially in China. METHODS:We present a case of a 48-year-old male liver transplant recipient with 2009 H1N1 influenza A virus.He received therapy for acute rejection after transplantation and was confirmed with H1N1 virus infection. RESULTS:The patient was started on oseltamivir(75 mg, orally twice daily)and had a benign hospital course,with defervescence and resolution of symptoms within 72 hours. The follow-up chest radiograph after discharge was normal. CONCLUSIONS:The 2009 H1N1 influenza in this hospitalized transplant recipient was relatively mild,and prolonged viral shedding was not noted.Oseltamivir can be a valid measure in immunocompromised individuals.

First isolation and identification of H1N1 swine influenza viruses in Colombian pig farms

The pig industry in Colombia has grown 30% in the last decade achieving high levels of technology and efficiency;in spite of that, respiratory diseases remain a constraint. Since 1970, serological evidence and histological findings suggested the role of swine influenza virus (SIV) as part of the porcine respiratory disease complex;nevertheless, elusive and molecular typing isolates are missing. This study was aimed at isolating SIV from intensive pig farms and to achieve molecular characterization to determine strains circulating in the field. In order to accomplish this goal, 242 samples were taken from nasal swabs, 25 from bronchial washes and 8 from lung tissue. Samples were collected during a period of three years, between 2008 and 2010 and were originated from 78 farms of the three main pig production regions of the country. The samples were transported in BHI broth with 2% antibiotic and antimycotic solution and stored at –70?C until processed. The swabs were inoculated in 9 - 11 days old embryo chicken eggs and in MDCK (Madin Darby Canine Kidney) cell cultures with the addition of trypsin. The isolates were identified by the HA (hemoagglutination) test and by RT-PCR targeting the HA (hemagglutinin), NA (Neuraminidase) and M (Matrix) genes. Full length sequence of the HA and NA glycoproteins from four selected virus isolates was conducted (Macrogen?. USA). As a result, fifteen SIV isolates from nine farms distributed in the three regions were obtained. Twelve of the isolates are related to the swine origin H1N1 virus that caused the 2009 influenza pandemic. The remaining three viruses were related to classical swine influenza viruses.