Avian influenza virus ecology in wild birds of Western Siberia

Background:The aim of the study was to explore the ecological diversity of wild birds in Siberia, which are the natural reservoir of avian influenza virus(AIV).Methods:Cloacal swabs and intestinal fragments were collected from wild migratory birds from 2007-2014. Isolated viruses were grown in the allantoic cavity of embryonated chicken eggs. The presence of virus was determined using hemagglutination assays. Primary identification and subtyping of influenza viruses was confirmed by RT-PCR.Results:A total of 2300 samples obtained from wild migratory birds of 8 orders were collected and tested. Influenza was detected in 185 birds of 3 orders. Species of family Anatidae(order Anseriformes) such as European Teal(Anas crecca), Garganey Teal(A. querquedula), and Shoveler(A. clypeata) play the main role in AIV circulation in the south of Western Siberia. The proportion of viral carriers among waterfowl ranged from 5.6 to 20% in 2007-2014. The order Charadriiformes had lower virus isolation rates of not more than 1.4%.Conclusions:Wild migratory waterfowl of orders Anseriformes and Charadriiformes are the main reservoir of AIV in the south of Western Siberia. This area plays a key role in persistence, evolution, and geographical distribution of avian influenza.

An infectious clone of the highly pathogenic porcine reproductive and respiratory syndrome virus: Topology of glycoprotein 3 (GP3) addressing the intrachain disulfide bonds

The highly pathogenic porcine reproductive and respiratory virus (hpPRRSV) with discontinuous 30 amino acid (aa) deletion as a gene marker has caused great economic loss in pig industry and since 2007 has become the dominant strain prevalent in China and Vietnam since 2007.Reverse genetics method is a powerful tool urgently needed to be used on the hpPRRSV to study the intriguing molecular mechanism of transcription,replication and the virulence determinant factors.In our study,we successfully constructed a fulllength infectious clone,prBJSY07,based on hpPRRSV isolate,BJSY07.The rescued virus,vrBJSY07,showed similar growth characters to those of the parental virus,BJSY07.We also found that a rescued virus vBJSY07 generated from pBJSY07 was viable but displayed decreased and delayed reproductive capacity,which might be caused by two amino acids mutations,S83C and S117C in glycoprotein 3 (GP3),acquired during the preparation of the infectious clone.The topology of the wild type GP3 and the mutant were further analyzed by bioinformatics and revealed that the mutated GP3 possessed slightly altered structure,most likely by forming a new disulfide bond between the two new cysteine residues.As GP3 is a cysteine-rich glycoprotein,common for viral glycoproteins,our results show that GP3 can accommodate even more cysteine mutations.Based on this,a topological model of GP3 is proposed by addressing the intrachain disulfides.

Interspecies transmission and host restriction of avian H5N1 influenza virus

Long-term endemicity of avian H5N1 influenza virus in poultry and continuous sporadic human infections in several countries has raised the concern of another potential pandemic influenza. Suspicion of the avian origin of the previous pandemics results in the close investigation of the mechanism of interspecies transmission. Entry and fusion is the first step for the H5N1 influenza virus to get into the host cells affecting the host ranges. Therefore receptor usage study has been a major focus for the last few years. We now know the difference of the sialic acid structures and distributions in different species, even in the different parts of the same host. Many host factors interacting with the influenza virus component proteins have been identified and their role in the host range expansion and interspecies transmission is under detailed scrutiny. Here we review current progress in the receptor usage and host factors.

Highly pathogenic avian influenza H5N1 Clade 2.3.2.1c virus in migratory birds,2014–2015

A novel Clade 2.3.2.1c H5N1 reassortant virus caused several outbreaks in wild birds in some regions of China from late 2014 to 2015.Based on the genetic and phylogenetic analyses,the viruses possess a stable gene constellation with a Clade 2.3.2.1c HA,a H9N2-derived PB2 gene and the other six genes of Asian H5N1-origin.The Clade 2.3.2.1c H5N1 reassortants displayed a high genetic relationship to a human H5N1 strain(A/Alberta/01/2014).Further analysis showed that similar viruses have been circulating in wild birds in China,Russia,Dubai(Western Asia),Bulgaria and Romania(Europe),as well as domestic poultry in some regions of Africa.The affected areas include the Central Asian,East Asian-Australasian,West Asian-East African,and Black Sea/Mediterranean flyways.These results show that the novel Clade 2.3.2.1c reassortant viruses are circulating worldwide and may have gained a selective advantage in migratory birds,thus posing a serious threat to wild birds and potentially humans.

Website for avian flu information and bioinformatics

Highly pathogenic influenza A virus H5N1 has spread out worldwide and raised the public concerns. This increased the output of influenza virus sequence data as well as the research publication and other reports. In order to fight against H5N1 avian flu in a comprehensive way, we designed and started to set up the Website for Avian Flu Information (http://www.avian-flu.info) from 2004. Other than the influenza virus database available, the website is aiming to integrate diversified information for both researchers and the public. From 2004 to 2009, we collected information from all aspects, i.e. reports of outbreaks, scientific publications and editorials, policies for prevention, medicines and vaccines, clinic and diagnosis. Except for publications, all information is in Chinese. Till April 15, 2009, the cumulative news entries had been over 2000 and research papers were approaching 5000. By using the curated data from Influenza Virus Resource, we have set up an influenza virus sequence database and a bioinformatic platform, providing the basic functions for the sequence analysis of influenza virus. We will focus on the collection of experimental data and results as well as the integration of the data from the geological information system and avian influenza epidemiology.

hNUDT16:a universal decapping enzyme for small nucleolar RNA and cytoplasmic mRNA

Human NUDT16(hNUDT16)is a decapping enzyme initially identified as the human homolog to the Xenopus laevis X29.As a metalloenzyme,hNUDT16 relies on divalent cations for its cap-hydrolysis activity to remove m7 GDP and m227GDP from RNAs.Metal also determines substrate specificity of the enzyme.So far,only U8 small nucleolar RNA(snoRNA)has been identified as the substrate of hNUDT16 in the presence of Mg2+.Here we demonstrate that besides U8,hNUDT16 can also actively cleave the m7 GDP cap from mRNAs in the presence of Mg2+or Mn2+.We further show that hNUDT16 does not preferentially recognize U8 or mRNA substrates by our cross-inhibition and quantitative decapping assays.In addition,our mutagenesis analysis identifies several key residues involved in hydrolysis and confirms the key role of the REXXEE motif in catalysis.Finally an investigation into the subcellular localization of hNUDT16 revealed its abundance in both cytoplasm and nucleus.These findings extend the substrate spectrum of hNUDT16 beyond snoRNAs to also include mRNA,demonstrating the pleiotropic decapping activity of hNUDT16.

Highly diversified Zika viruses imported to China, 2016

Dear Editor, First discovered during 1947 in Uganda from febrile rhesus macaques, Zika virus （ZIKV） is a mosquito-borne, reemerging flavivirus historically known to be present in much of Africa and Asia, occasionally causing outbreaks amongst the local populace （Haddow et al., 2012）. ZIKV infections in humans are mostly asymptomatic, but a small percentage of patients may show clinical symptoms such as a fever and rash, which resolve within a week or less.