Novel reassortant H5N6 highly pathogenic influenza A viruses in Vietnamese quail outbreaks     

《Comparative immunology, microbiology and infectious diseases》2018

Avian influenza A H5N6 virus is a highly contagious infectious agent that affects domestic poultry and humans in South Asian countries. Vietnam may be an evolutionary hotspot for influenza viruses and therefore could serve as a source of pandemic strains. In 2015, two novel reassortant H5N6 influenza viruses designated as A/quail/Vietnam/CVVI01/2015 and A/quail/Vietnam/CVVI03/2015 were isolated from dead quails during avian influenza outbreaks in central Vietnam, and the whole genome sequences were analyzed. The genetic analysis indicated that hemagglutinin, neuraminidase, and polymerase basic protein 2 genes of the two H5N6 viruses are most closely related to an H5N2 virus (A/chicken/Zhejiang/727079/2014) and H10N6 virus (A/chicken/Jiangxi/12782/2014) from China and an H6N6 virus (A/duck/Yamagata/061004/2014) from Japan. The HA gene of the isolates belongs to clade 2.3.4.4, which caused human fatalities in China during 2014–2016. The five other internal genes showed high identity to an H5N2 virus (A/chicken/Heilongjiang/S7/2014) from China. A whole-genome phylogenetic analysis revealed that these two outbreak strains are novel H6N6-like PB2 gene reassortants that are most closely related to influenza virus strain A/environment/Guangdong/ZS558/2015, which was detected in a live poultry market in China. This report describes the first detection of novel H5N6 reassortants in poultry during an outbreak as well as genetic characterization of these strains to better understand the antigenic evolution of influenza viruses.  相似文献   

不同温度下圆叶决明降解过程红壤可溶性氮及氮水解酶动态变化研究   总被引：1，自引：0，他引：1  

钟珍梅  游小凤  翁伯琦  邢世和  应朝阳 《草地学报》2020,28(1):95-103

为了探明圆叶决明（Chamaecrista rotundifolia）降解过程果园红壤供氮水平的变化规律，本研究采用模拟培养试验，研究15℃和25℃培养果园红壤硝态氮、铵态氮、可溶性总氮、可溶性有机氮含量的变化及脲酶、蛋白酶、天冬酰胺酶活性的变化。结果表明，圆叶决明降解过程果园红壤4种可溶性氮含量均显著提高，且在培养140 d达到最大值，25℃培养的效果更佳。其中，可溶性总氮、可溶性有机氮和硝态氮含量随时间的动态变化可用三次曲线方程来拟合。圆叶决明降解过程还能显著提高脲酶、蛋白酶和天冬酰胺酶的活性，其中蛋白酶活性和脲酶活性的变化可用指数方程和三次曲线方程来拟合。本研究认为圆叶决明降解过程可提高果园红壤可溶性氮含量，因此可通过翻压圆叶决明提高土壤的供氮水平。  相似文献   

南果梨周年干物质与氮磷钾积累动态   总被引：3，自引：0，他引：3  

刘秀春  陈丽楠  王炳华  范业宏  陈清 《植物营养与肥料学报》2016,22(3):786-793

【目的】明确南果梨干物质积累特征和氮磷钾养分周年动态积累规律,为南果梨优化施肥量和施肥时期提供依据。【方法】以12年生南果梨树为试材,采用田间采样和树体分解方法,分别于萌芽后10 d(萌芽期)、 30 d(花期)、 65 d(幼果膨大期)、 100 d(果实膨大或新稍停止生长期)、 130 d(果实着色前)、 155 d(果实采收期)、 185 d(采收后)、 210 d(落叶前)8个生育期,选干周和树高一致的3株树,将树体连根从土壤中挖出,分出果实、 叶片、 枝条、 主干、 主根、 侧根、 须根,各器官单独称重,并取200 g左右的鲜样按清水、 洗涤剂、 清水、 1%盐酸、 3次去离子水冲洗、 杀青、 烘干后,电磨粉碎过0.15 mm筛,测定样品中氮、 磷、 钾含量。【结果】1)南果梨周年生育期内,树体干物质当年净积累量为18.4 kg/plant,干物质累积速率出现两次累积高峰,分别是幼果膨大期(0.15 kg/d)和采收期(0.11 kg/d)。2)南果梨树体总氮周年积累量为154.0~301.0 g,新生器官为0~116.2 g,果实膨大期达到最高;多年生器官氮积累量为154.0~194.8 g,落叶前达到最高。3)南果梨树体总磷周年积累量为17.1~37.2 g,果实着色前最高。其中新生器官为13.7 g,果实采收期最高;多年生器官为17.1~24.9 g,果实转色期最高。4)南果梨树体总钾周年积累量为27.9~174 g。新生器官钾为97.3 g,采收期最高;多年生器官钾为27.6~76.6 g,落叶前最高。5)产量大约为17 t/hm2的12年生南果梨从萌芽到落叶前树体当年氮磷钾的单株净累积量分别为146.2、 20.1、 146.1 g,折合1000 kg果实经济产量需吸收氮(N)、 磷(P)、 钾(K)5.4、 0.7、 5.4 kg。【结论】南果梨周年干物质单株积累总量为41.4 kg,当年净积累量为19.7 kg。南果梨干物质积累主要集中在花期到果实膨大期和果实转色到落叶前,分别占47.3% 和47.5%。南果梨从萌芽到落叶前氮、 磷、 钾的单株净累积量分别为146.2、 20.1、 146.1 g,每1000 kg果实经济产量需吸收氮(N)、 磷(P)、 钾(K)5.4、 0.7、 5.4 kg。从开花到果实膨大期和从果实着色到采收后30天对氮吸收分别占总氮累积量的39.0%和49.0%,而磷、 钾的累积从萌芽到开花较快,到果实膨大期磷的累积达67.4%,钾的累积达65.1%,果实膨大期是干物质和氮磷钾积累的关键时期。  相似文献   

Bird flu (H7N9) outbreak and its implications on the supply chain of poultry meat in China     

《The Journal of Applied Poultry Research》2015,24(2):215-221

During the past two decades, food safety issues in China not only posed serious threats to Chinese consumers but also damaged the image of Chinese products internationally. In China, food safety is not only about scientific discoveries, advanced laboratories, and sanitation equipment; it is more about the role of different players in the food supply chain. The poultry meat supply chain is instrumental in the spread of the avian influenza A virus (H7N9), raising questions about how policymakers respond to such threats and whether industries need to be restructured to manage and control this epidemic so that it does not recur. As a short-term measure, to prevent the spread of this disease, government authorities enforced the closure of live bird markets (LBM) in disease-affected areas of China. However, in the long term, the poultry meat supply chain needs to be restructured. The aim of the current study was to analyze distribution channels for chicken meat in China and then describe arrangements in poultry meat sectors that incorporate small- and medium-scale producers into the supply chain while responding to shifts in LBMs. We also assessed the role of LBMs in spreading H7N9 and how these interventions affect the poultry meat supply chain in the Chinese market.  相似文献   

Proton accumulation accelerated by heavy chemical nitrogen fertilization and its long-term impact on acidifying rate in a typical arable soil in the Huang-Huai-Hai Plain     

HUANG Ping  ZHANG Jia-bao  XIN Xiu-li  ZHU An-ning  ZHANG Cong-zhi  MA Dong-hao  ZHU Qiang-gen  YANG Shan  WU Sheng-jun 《中国农业科学(英文版)》2015,(1)

Cropland productivity has been signiifcantly impacted by soil acidiifcation resulted from nitrogen (N) fertilization, especialy as a result of excess ammoniacal N input. With decades’ intensive agricul...  相似文献   

外源氮添加对湿地土壤N_2O排放量的影响     

史昊先  高晓霞  于景丽  赵吉 《农业环境与发展》2014,(5)

为搞清湿地土壤驱动N2O排放的关键氮源类型,有效减少湿地N2O的排放,本文通过室内控制温湿度,用气相色谱法分析不同外源氮素对湿地N2O排放的影响。结果表明:外加氮源组总是高于对照组N2O排放量(4.4 mg·m-3)。在设定的剂量范围内,单独添加尿素或尿素与硝酸铵1∶1配合时N2O排放量呈现先增后减的单峰分布趋势,峰值分别为10.6 mg·m-3和229.0 mg·m-3;单独添加硝酸铵时N2O排放量(32.6~111.0 mg·m-3)随着氮素添加量增加呈现持续上升趋势。单独添加尿素或硝酸铵、尿素与硝酸铵1∶1配合均促进N2O的排放,但硝酸铵尿素混合添加对N2O排放量的贡献单独添加硝酸铵单独添加尿素。这为预测内蒙古高原区农牧交错带湿地氮素输入可能带来的温室效应和有效减排提供科学依据。  相似文献   

优化施肥对春小麦产量、氮素利用及氮平衡的影响   总被引：3，自引：0，他引：3  

赵营  周涛  郭鑫年  梁锦秀  吴霞  冀宏杰  张维理 《干旱地区农业研究》2011,29(6):119-124

2009 ～ 2010年,在宁夏引黄灌区分别以宁春11号和宁春16号小麦为供试作物,利用田间试验研究了优化施肥(OPT)和习惯施肥(CON)对春小麦产量、氮素吸收利用和土壤硝态氮累积的影响,表观评估了土壤—小麦体系氮素平衡.结果表明,相对于CK处理,OPT和CON都显著提高春小麦籽粒产量地上部生物量,并促进籽粒N和地上...  相似文献   

新型尿素对冬小麦产量及氮素吸收利用的影响     

尹焕丽  岳艳军  常凤  王海标  苗玉红  王宜伦 《中国农业科技导报》2020,22(5):145-152

为明确新型尿素在冬小麦的应用效果，采用田间试验，研究了普通尿素（Urea）、控失尿素（LC Urea）、海藻酸尿素（H Urea）、聚能网尿素（N Urea）、含锰尿素（Mn Urea）、控失尿素一次施肥（LC Urea 1）、普通尿素+等量锰（Urea+Mn）和不施肥（CK）对冬小麦产量、叶片SPAD、叶片光合生理特性和氮素吸收利用的影响。结果表明，LC Urea和H Urea处理较Urea处理的小麦拔节期叶片SPAD分别显著提高1500%和1300%，灌浆期净光合速率分别显著增加3304%和2076%，气孔导度分别显著提高2609%和2174%，氮素积累量分别显著增加1439%和1236%，氮肥利用率分别提高4575%和3902%。N Urea和Mn Urea处理与Urea处理的产量无显著差异，LC Urea和H Urea处理较Urea处理显著增产1449%和1333%。控失尿素和海藻酸尿素能够有效提高穗数，改善冬小麦光合生理特性，促进氮素吸收利用，提高冬小麦产量和氮肥利用率，可在豫北潮土区推广应用。  相似文献   

不同肥料对毛竹冬笋品质特征的影响   总被引：3，自引：0，他引：3  

郑林水  周紫球  陆媛媛  吴礼栋 《林业科技》2011,36(4):43-45

连续使用3种不同肥料3年后对冬笋品质特征影响的研究结果表明：蛋白质平均含量的百分比比对照减少0.2～0.35,还原米糖含量的百分比比对照减少0.05～0.12,脂肪平均含量中只有处理C的百分比比对照减少0.1,可溶性固形物的含量没有明显变化均为7.5%,粗纤维含量的百分比比对照增加0.07～0.1,砷（As）含量为绿色食品控制标准的12%～20%,铅（Pb）含量为绿色食品控制标准的51%～97%,镉（Cd）含量为绿色食品控制标准的58%～74%。  相似文献   

Screening and Identification of Candidate Proteins Interacting with BmHSP60 in the Silkworm (Bombyx mori)     

DONG ZhanQi  JIANG YaMing  PAN MinHui 《中国农业科学》2019,52(2):376-384

  相似文献