Tianhou Wang

A novel highly pathogenic H5N8 avian influenza virus isolated from a wild duck in China

Migrating wild birds are considered natural reservoirs of influenza viruses and serve as a potential source of novel influenza strains in humans and livestock. During routine avian influenza surveillance conducted in eastern China, a novel H5N8 (SH‐9) reassortant influenza virus was isolated from a mallard duck in China. blast analysis revealed that the HA, NA, PB1, PA, NP, and M segments of SH‐9 were most closely related to the corresponding segments of A/duck/Jiangsu/k1203/2010 (H5N8). The SH‐9 virus preferentially recognized avian‐like influenza virus receptors and was highly pathogenic in mice. Our results suggest that wild birds could acquire the H5N8 virus from breeding ducks and spread the virus via migratory bird flyways.

Monoclonal antibody recognizing SLLTEVET epitope of M2 protein potently inhibited the replication of influenza A viruses in MDCK cells

The ectodomain of influenza A virus M2 protein (M2e) is composed of 24 amino acids and induces antibodies with inhibitory effect against a broad spectrum of influenza A subtypes in vitro and in vivo. Although relatively conserved, 21 M2e variants emerged in recent influenza A strains, most of the mutations appeared in the middle part of M2e domain. In this study, we characterized the in vitro inhibition efficacy of a monoclonal antibody (mAb) M2e8-7 recognizing the N terminus highly conserved epitope SLLTEVET (aa 2-9) which is common for both M1 and M2 proteins. Peptide binding assay showed that mAb M2e8-7 reacted strongly with M2e and 19 M2e variant peptides. The mAb M2e8-7 potently inhibited the replication of influenza A virus H1 and H3 subtypes in MDCK cells. Two important amino acids in M2e epitope, Threonine at position five and the Glutamic acid at position six, were identified to lead antibody-escaping variants. These results brought new insight in developing vaccine and therapeutic agents against influenza A virus infections.

Nsp1 proteins of group I and SARS coronaviruses share structural and functional similarities

Abstract The nsp1 protein of the highly pathogenic SARS coronavirus suppresses host protein synthesis, including genes involved in the innate immune system. A bioinformatic analysis revealed that the nsp1 proteins of group I and SARS coronaviruses have similar structures. Nsp1 proteins of group I coronaviruses interacted with host ribosomal 40S subunit and did not inhibit IRF-3 activation. However, synthesis of host immune and non-immune proteins was inhibited by nsp1 proteins at both transcriptional and translational levels, similar to SARS coronavirus nsp1. These results indicate that different coronaviruses might employ the same nsp1 mechanism to antagonize host innate immunity and cell proliferation. However, nsp1 may not be the key determinant of viral pathogenicity, or the factor used by the SARS coronavirus to evade host innate immunity.

Seasonal change and habitat selection of shorebird community at the South Yangtze River Mouth and North Hangzhou Bay, China

Abstract Coastal regions are important habitats for migratory shorebirds. The aim of the study is to understand habitat use by migratory shorebirds and to develop a conservation strategy in the sustainable use of wetlands. From March 2004 to January 2005, we conducted a seasonal shorebirds census in ten coastal habitats along the South Yangtze River mouth and North Hangzhou Bay, simultaneously examining the relative seasonal abundance of shorebirds and their spatial distribution. A total of 25 species were identified, the dominant seasonal species were Great Knot ( Calidris tenuirostris ), Sharp-tailed Sandpiper ( Calidris alpine ) and Red-necked Stint ( Calidris ruficollis ) in spring; Kentish Plover ( Charadrius alexandrinus ), Common Greenshank( Tringa nebularia ) and Lesser Sand Plover ( Charadrius mongolus ) in summer; Kentish Plover, Red-necked Stint and Common Greenshank in autumn; Dunlin( Calidris alpine ), Kentish Plover and Marsh Sandpiper ( Tringa stagnatilis ) in winter. These species accounted for more than 85% of the total shorebirds. The numbers of shorebirds counted was highest in spring and then in autumn, winter and summer respectively. Among the four seasons, there were few significant differences in the number of bird species between the sites outside the seawall (intertidal mudflat) and the sites inside the seawall (artificial wetland), but the average density of shorebirds was obviously different. The habitat-selection analysis of the environmental factors (outside and inside the seawall) impacting on the shorebird community was made in the 10 study sites with Canonical Correspondence Analysis. The study results indicated that: (1) Outside the seawall, the widths of the total intertidal mudflat and bare mudflat were the key factors affecting the shorebirds; the proportion of bulrush ( Scirpus×mariquete ) covering and supertidal mudflat width had a positive correlation with the abundance of birds, while human disturbance and the proportion of both reed ( Phragmites communis ) and smooth cord-grass ( Spartina alterniflora ) covering in total surveyed areas had negative impacts on bird numbers; (2) Inside the seawall, the proportions of areas with shallow water and mudflats occupying the total surveyed area were key factors influencing the number of birds; the size of the bulrush area should have a positive impact on the appearance of shorebirds. Habitats with heavy human disturbance, dense reed and smooth cord-grass or a high water level were not conducive to be inhabited by shorebirds.

Changes in the spatial distribution of migratory shorebirds along the Shanghai shoreline, China, between 1984 and 2004

Abstract Migratory shorebirds in the East Asian—Australasian Flyway use the Shanghai shoreline as an important stopover site. Until recently, little was known about the influence of intensive reclamation on the shorebirds using this shoreline. We investigated the distribution of shorebirds in 10 fixed-sample sites in 2004–05 and compared the results with those of surveys at the same sites in 1984–85; we also examined physical changes in intertidal wetlands and coastal land-use at these sites. In 2004–05, 25 shorebird species were recorded, and the seasonal abundance of shorebirds in 2004–05 was similar to that recorded in the 1980s, but the number of species observed in both northern and southern migration periods declined between 1984–85 and 2004–05 even though the overall numbers of birds had not. Since the 1980s, over 500 km2 of intertidal mudflats along the Shanghai shoreline have been reclaimed, though ∼190 km2 of these mudflats have been reclaimed but not yet developed and could be considered fairly high-value habitat for shorebirds. Most of the shore-birds that were observed were on these reclaimed but undeveloped mudflats. The physical characteristics of the mudflats had been transformed over the preceding two decades through reclamation, siltation, erosion and, at some sites, artificial vegetation planting, and two habitat variables—the width of mudflats and the width of the upper intertidal zone—significantly affect the abundance and distribution of shorebirds. We discuss some implications for conservation related to rules and guidelines for reclamation of wetlands, and make recommendations on land-use procedures for artificial wetlands.

Characterization of the Antiviral Activity for Influenza Viruses M1 Zinc Finger Peptides

We sought to investigate the cellular uptake and antiviral activity for the M1 zinc finger peptides derived from influenza A and influenza B viruses in vitro. No cellular uptake was detected by fluorescent microscopy for the synthetic zinc finger peptides. When flanked to a cell permeable peptide Tp10, the zinc finger recombinant proteins were efficiently internalized by MDCK cells. However, no antiviral activity was detected against homologous or heterologous virus infections for the synthetic peptides or the Tp10-flanked recombinant proteins, regardless treated with or without Zn2+. Nevertheless, MDCK cell constitutively expressing the M1 zinc finger peptides in cell nuclei potently inhibited replication of homologous, but not heterologous influenza viruses. Adenoviral vector delivered M1 zinc finger peptides also exhibited potent antiviral activity against homologous viruses challenge. Transduction at 100 PFU dose of recombinant adenovirus efficiently protected 99% of the cells from 100 TCID50 of different virus infections for both peptides. These results brought new insight to the antiviral researches against influenza virus infections.

Identification of two novel avian influenza a (H5N6) viruses in wild birds, Shanghai, in 2016

The H5N6 avian influenza virus (AIV) has been continuously reported in wild birds, which may contribute to further geographical spread during their long-distance migrations. Active AIV surveillance in wild birds was conducted during October and November 2016 in Shanghai, China. Two novel influenza A (H5N6) viruses were detected in samples from migratory waterfowl that are genetically similar to recent South Korea and Japan H5N6 viruses collected in 2016 and 2017, highlighting the role of migratory waterfowl in the dissemination of H5N6 viruses along migratory flyways.

Migratory Waterbirds Response to Coastal Habitat Changes: Conservation Implications from Long-term Detection in the Chongming Dongtan Wetlands, China

Changes in waterbird populations in relation to changes in their habitat are of great concern in the Chongming Dongtan wetlands, one of the most important stopovers for migrating waterbirds in the East Asian–Australasian Flyway. We analyzed the relationship between the changes in the dominant waterbird populations (Charadriidae, Anatidae, Ardeidae, and Laridae) and the changes in their corresponding habitats from 2000 to 2012. In natural wetlands, the species number of Anatidae was significantly positively correlated with the Scirpus mariqueter (hereafter Scirpus) habitat but significantly negatively correlated with the Phragmites australis (hereafter Phragmites) habitat. The densities of Charadriidae and Laridae were both significantly positively correlated with the deep water habitat but significantly negatively correlated with the Spartina alterniflora (hereafter Spartina) habitat. The density of Charadriidae, however, also exhibited significantly positive correlation with the Scirpus habitat. In the aquaculture ponds, the changes in the density of Anatidae in the winter were significantly negatively correlated with the changes in aquaculture ponds. Other waterbirds only exhibited positive or negative correlation trends with their habitats, which did not reach the statistically significant levels. Consequently, changes in waterbird populations are significantly correlated with changes in natural wetlands and aquaculture ponds in the Chongming Dongtan wetlands. Natural wetlands and aquaculture ponds are important to migratory waterbirds during the peak of migration and wintering. Our results promote the development of wetland management strategies for protecting migratory waterbirds in the coastal area of the Yangtze River.

Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory seasons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habitats (intertidal bare mudflat and Scirpus × mariqueter/Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13–0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds’ utilization efficiency of the resources in the Jiuduansha Wetland.