Multiple amino acid substitutions are involved in the adaptation of H9N2 avian influenza virus to mice

To explore adaptation of avian influenza virus to mice we previously performed serial lung-to-lung passages of the influenza A/Chicken/Jiangsu/7/2002 (H9N2) strain, resulting in the isolation of a variant influenza strain lethal for mice. We now report that virulence correlates with improved growth characteristics on mammalian cells and extended tissue tropism in vivo. Sequencing of the complete genomes of the wild-type and mouse-adapted viruses revealed 25 amino acid substitutions. Some were found to reiterate known substitutions in human and swine H9N2 influenza isolates. Functions affected include nuclear localization signals and sites of protein and RNA interaction, while others are known determinants of pathogenicity and host specificity such as the viral polymerase PB2 E627K substitution. These observations suggest that enhanced growth characteristics and modified cell tropism may contribute to increased virulence in mice. We conclude that multiple amino acid substitutions are likely to be involved in the adaptation of H9N2 avian influenza virus to mice.     

雷公山雉类猎捕状况调查报告

本文对雷公山地区的２５个村寨、６９位猎人自１９８９～１９９３年４年来的雉类猎捕状况作了调查统计，面积４７３ｋｍ２。结果表明：４年来雉类猎捕方法有８种，猎捕量计７３２只，年平均１８３只，平均狩猎强度为３．９５只／（人·ａ），均逐年下降，这对该地区雉类资源的现状和今后的保护提供了依据。     

Association of polymorphisms for nuclear receptor coactivator 1 gene with egg production traits in the maternal line of Shaobo hens

1. The objectives of the study were to find polymorphic sites and elucidate the association between SNPs in the nuclear receptor coactivator 1 (NCOA1) gene and reproductive traits. 2. SNPs were detected by PCR-SSCP and DNA sequencing. Four SNPs were detected, including T10155007A, T10125838C, G10118492A and G10109315T. Three polymorphisms were associated with total egg production at the age of 300 d and the G10109315T polymorphism was associated with age at first egg. 3. In conclusion, the NCOA1 gene can be used as a molecular marker for reproductive traits in hens.     

DNA Methylation Pattern in Pronuclear-Stage Mouse Embryos: Effect of Oocyte Vitrification

This study was conducted to investigate the pattern of DNA methylation in pronuclearstage mouse embryos derived from vitrified-warmed oocytes.Mouse oocytes at metaphase Ⅱ (MⅡ) stage of meiosis were all...     

Green tea polyphenols supplementation alters immunometabolism and oxidative stress in dairy cows with hyperketonemia

Peripartal cows often experience negative energy balance, and are therefore prone to suffering from metabolic diseases such as hyperketonemia, which causes financial losses in dairy farms. This study aimed to investigate the effect of green tea polyphenol (GTP) supplementation during the periparturient period on production performance, oxidative stress and immunometabolism in dairy cows with hyperketonemia. One hundred Holstein cows were assigned to GTP (0.2 g/kg DM; n = 50) or control (without GTP; n = 50) group based on body weight, previous milk yield, and parity on d 15 before expected parturition. Subsequently, 10 cows with hyperketonemia were selected from each group, according to blood β-hydroxybutyric acid (BHBA) concentration between 1.2 and 2.9 mmol/L from 2 to 3 d postpartum. All cows were fed a close-up diet and a lactation diet with or without GTP supply from 15 d prepartum until 30 d postpartum. Milk and blood samples were obtained from 20 cows selected with hyperketonemia on 10, 20, and 30 d postpartum. Compared with control cows, greater milk yield and lower somatic cell count were observed in GTP cows. The GTP group had lower concentrations of BHBA, free fatty acids, cholesterol, triglyceride, reactive oxygen species, malondialdehyde, and hydrogen peroxide, greater concentrations of glucose, lower activities of aspartate aminotransferase, alanine aminotransferase, and glutamyl transpeptidase, alongside greater activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity. Additionally, GTP supplementation up-regulated concentrations of interleukin-6 and interleukin-10, but down-regulated concentrations of tumor necrosis factor-α, interleukin-1β, interleukin-2, interleukin-8, and interferon-γ in plasma. Greater concentrations of plasma immunoglobulin G were also detected in the GTP group. Overall, the data suggested that GTP supplementation from 15 d prepartum to 30 d postpartum improved the milk yield and health status in cows with hyperketonemia during early lactation.     

科技扶贫种桑养蚕新技术下乡活动在阳山县举行

2002年1月30日广东省丝绸(集团)公司、广东省扶贫开发领导小组办公室在阳山县文化中心广场联合举办了《科技扶贫种桑养蚕新技术》下乡活动。承办这次活动的是广东省蚕业集团有限公司,同时阳山县委县政府、阳山县丝绸公司和阳山     

奶牛的有机锌应用效果研究进展

就有机锌对奶牛的营养作用效果、影响有机锌作用效果的因素进行综述。认为添加有机锌可提高奶牛的产奶性能、免疫机能、繁殖性能,改善体健康。同时影响有机锌作用效果的因素有:有机锌的产品质量、添加量和添加时期、饲料营养水平、参照物类型和评价指标等。     

江西省萍乡市某羊场布鲁菌病的流行病学分析

江西省萍乡市某山羊场妊娠母羊散发流产,为了分析该羊场流产的发生是否与布鲁菌感染有关,同时掌握该羊场布鲁菌病的流行情况,随机抽样采血共分离得到100份山羊血清,首先使用虎红平板凝集试验进行初步鉴定,然后通过试管凝集试验重新检测阳性血清。结果表明,该羊场布鲁菌病阳性率为20％。由此可以得出,该羊场的布鲁菌病防控工作存在较严重的问题,应制定有效的防治措施,将山羊布鲁菌病的检测纳入日常疾病监测工作中,最终达到净化该病的目的。