Molecular genetic characterization of H5N1 influenza virus strains isolated from poultry in the Kurgan region in 2005

In the second half of 2005, a large-scale outbreak of influenza in poultry and wild birds was caused by a highly pathogenic H5N1 influenza virus in Russia. The level of pathogenicity is a polygenic trait, and most individual genes contribute to the influenza A virus pathogenicity in birds, animals, and humans. The full-length nucleotide sequences were determined for H5N1 strains isolated in the Kurgan region (Western Siberia). The structure of viral proteins was analyzed using the deduced amino acid sequences. The receptor-binding site of hemagglutinin (HA) in strains A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005 was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. The structure of the basic amino acid cluster located within the HA cleavage site was identical in all isolates: QGERRRKKR. According to the neuraminidase structure, all H5N1 isolates from the Kurgan region were assigned to the Z genotype. Amino acid residues typical for the avian influenza virus were revealed in 30 out of 32 positions of M1, M2, NP, PA, and PB2, determining the host range specificity. One of the strains contained Lys at position 627 of PB2. Isolates from the Kurgan region were shown to have a remantadine-sensitive genotype. Both strains contained Glu at position 92 of NS1, indicating that the virus is interferon-resistant. Phylogenetic analysis related the Kurgan isolates to subclade 2 of clade 2 of highly pathogenic H5N1 influenza viruses.     

Host cellular signaling induced by influenza virus

A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell’s innate immune response against influenza virus, while others are essential for efficient influenza virus replication. This review examines the cellular signaling induced by influenza virus infection in host cells, including host pattern recognition receptor (PRR)-related signaling, protein kinase C (PKC), Raf/MEK/ERK and phosphatidylinositol- 3-kinase (PI3K)/Akt signaling, and the corresponding effects on the host cell and/or virus, such as recognition of virus by the host cell, viral absorption and entry, viral ribonucleoprotein (vRNP) export, translation control of cellular and viral proteins, and virus-induced cell apoptosis. Research into influenza virus-induced cell signaling promotes a clearer understanding of influenza virus-host interactions and assists in the identification of novel antiviral targets and antiviral strategies.     

Climatic adaptations in the Drosophila immigrans species group: seasonal migration and thermal tolerance

Abstract. 1. In central Japan, Drosophila curviceps Okada and Kurokawa was collected in spring and autumn but not in summer at lowlands (alt. 500–1200 m), while it was collected only in summer at highlands (1500–2000 m). Experiments on its thermal tolerance suggested that summer heat at the lowlands and winter low temperatures at the highlands were adverse to this species. It is considered that this species escapes from these extreme temperatures by undergoing seasonal migration between the lowlands and the highlands. This species had no photo-periodic diapause and bred at both lowlands and highlands.
2. D.immigrans Sturtevant was less cold-hardy but more heat-tolerant than D.curviceps. It is considered that this species is unable to overwinter outdoors at least in the study areas (i.e. alt. 500m or higher in central Japan) and its populations in these areas originate with migrants from warmer areas.
3. D.albomicans Duda, a subtropical species, was less cold-hardy but more heat-tolerant than the above two species.
4. Climatic adaptations and distributions of these species are discussed with reference to their thermal tolerance.     

Highly pathogenic H5N1 influenza virus causes coagulopathy in chickens

Severe hemorrhage at multiple organs is frequently observed in chickens infected with highly pathogenic avian influenza (HPAI) A viruses. In this study we examined whether HPAI virus infection leads to coagulation disorder in chickens. Pathological examinations showed that the fibrin thrombi were formed in arterioles at the lung, associated with the viral antigens in endothelial cells of chickens infected intravenously with HPAI virus. Hematological analyses of peripheral blood collected from the chickens revealed that coagulopathy was initiated at early stage of infection when viral antigens were detected only in the endothelial cells and monocytes/macrophages. Furthermore, gene expression of the tissue factor, the main initiator of blood coagulation, was upregulated in the spleen, lung, and brain of HPAI virus-infected chickens. These results suggest that dysfunction of endothelial cells and monocytes/macrophages upon HPAI virus infection may induce hemostasis abnormalities represented by the excessive blood coagulation and consumptive coagulopathy in chickens.     

The Marine Component of Ichthyofauna in the Mouth Area and Lower Course of the Tumen River

The species composition of typically marine fishes in the lower course and mouth area of the Tumen River (Sea of Japan) is examined based on original faunistic collections and literature data. Thirty-three species belonging to 19 families were recorded. The ratio of species of boreal and subtropical origins was found; temporary and seasonal migrants were identified. Some species (Platichthys stellatus, Myoxocephalus stelleri, Strongylura anastomella, and Mugil cephalus) can be considered indicators of the state of the environment. It is noted that yearly surveys of the marine fish composition in the river zone are needed for monitoring climatic and anthropogenic influences.     

五种温带森林土壤微生物生物量碳氮的时空格局

土壤微生物是森林生态系统中的重要分解者,在碳和氮循环中起着重要作用,同时也是对环境变化的敏感指示者。采用氯仿熏蒸浸提法测定了我国东北地区5种温带森林土壤微生物生物量碳(Cmic)和氮(Nmic)的季节动态及其在土壤中的垂直变化。结果表明:林型之间Cmic和Nmic差异显著(P0.01)。落叶松林、红松林、蒙古栎林、杨桦林、硬阔叶林的Cmic的变化范围依次为:278937mgkg-1、2181020mgkg-1、313891mgkg-1、5101092mgkg-1、4401911mgkg-1;其Nmic的变化范围依次为:1872mgkg-1、18103mgkg-1、2495mgkg-1、43125mgkg-1、40208mgkg-1。所有林型的Cmic和Nmic均随土壤深度的增加而下降。Cmic和Nmic基本上呈现出生长季开始之前下降、生长季结束时上升、其中出现12个峰值的季节变化格局,但峰值大小和出现时间随林型和土壤层次而变。010cm土层的Cmic和Nmic季节变化较大。Cmic和Nmic与凋落叶量、土壤有机碳含量和土壤总氮含量呈显著正相关。Cmic与土壤含水量呈正相关,而与土壤温度呈负相关。不同林型凋落物数量和组成、土壤理化性质的差异是导致其土壤微生物生物量时空格局差异的主要因素。     

枸杞多糖对H5N1流感全病毒灭活疫苗的体液免疫增强作用

探讨枸杞多糖(Lycium barbarum polysaccharide,LBP)作为佐剂对H5亚型流感病毒全病毒灭活疫苗的体液免疫增强效果。将流感病毒A/Vietnam/1194/2004(H5N1)灭活疫苗与不同剂量的枸杞多糖混合后以腹腔注射的方式共同免疫小鼠,免疫后三周收集血清用于特异性抗体检测。实验中设立氢氧化铝佐剂组作对照共同评价LBP作为佐剂的免疫增强效果。结果显示,小鼠血清中针对H5灭活疫苗的特异性抗体水平在一定范围内随着LBP剂量的增加而提高。LBP在800μg剂量时血清特异性抗体水平较无佐剂组显著增强,并与氢氧化铝佐剂组大致相当。因而,LBP有可能成为一种有效的流感灭活疫苗免疫佐剂。