Genetic diversity of avian infectious bronchitis coronavirus in recent years in China

Fifty-six isolates of avian infectious bronchitis virus (IBV) were obtained from different field outbreaks in China in 2010, and they were genotyped by comparison with 19 reference strains in the present study. The results showed that LX4-type isolates are still the predominant IBVs circulating in chicken flocks in China, and these isolates could be grouped further into two clusters. Viruses in each cluster had favored amino acid residues at different positions in the S1 subunit of the spike protein. In addition, a recombination event was observed to have occurred between LX4- and tl/CH/LDT3/03I-type strains, which contributed to the emergence of a new strain. The most important finding of the study is the isolation and identification of Taiwan II-type (TW II-type) strains of IBV in mainland China in recent years. The genome of TW II-type IBV strains isolated in mainland China has experienced mutations and deletions, as demonstrated by comparison of the entire genome sequence with those of IBV strains isolated in Taiwan. Pathogenicity testing and sequence analysis of the 3' terminal untranslated region revealed that TW II-type IBV strains isolated in mainland China have a close relationship with the embryo-passaged, attenuated TW2296/95.     

黄芪多糖、淫羊萑多糖和淫羊萑总黄酮的城疫毒感染细胞的影响

将黄芪多糖（APS）、淫羊萑多糖（EPS）、淫羊萑总黄酮（EF）分别与新城疫病毒（NDV）Ⅰ、Ⅳ系以3种顺序加入到培养24h的鸡胚成纤维细胞（CEF）中，即先加中药后接种病毒、先接种病毒后加中药、病毒和中药混合感作后同时加入。于病毒接种后72h测定NDVⅠ系的半数组织培养感染剂量（TCID50）和NDVⅣ系的血凝效价，以评价3种中药成分对NDV感染细胞的影响。结果表明，APS和EPS仅在先于病毒加入时对NDV有抑制作用，而EF无论以何种方式给药均呈抑制作用。提示它们有一定的抗病毒作用，且与其浓度有相关性。     

龛沟是崩岗早期发育的形态标志

为探究我国南方花岗岩红壤地区崩岗的起始标志和发育阶段。在湖北省通城县和广西岑溪市2个典型崩岗区调查崩岗的发育过程。结果表明,2个调查区都存在一种细沟发育而来的龛状浅沟,将其命名为龛沟。龛沟具有3个特征：上游有明显细沟,沟壁陡峭且具有上窄下宽的宽深梯形形态。龛沟主要发生在砂土层裸露、具有一定汇水面积和局地坡度>30°的裸露坡面。龛沟是一种特殊形态的浅沟,其定义、形态和侵蚀营力都不同于常规浅沟、切沟和Amphitheatershaped canyons等沟蚀地貌。龛沟是沟道侵蚀从水力侵蚀为主变为水力和重力复合侵蚀的过程,是崩岗起始发育的启动标志,其发生原因与花岗岩红壤上红（黏）下砂的土层结构有关。以龛沟出现为标志,将崩岗的发育阶段重新划分为早期准备阶段、初期启动阶段、中期发展阶段和后期成熟阶段。龛沟的特点和研究区的崩岗治理效果表明,削坡开级的治理方式不适合在红土层较薄的花岗岩红壤地区使用。龛沟的发现将推进对崩岗早期发育的研究,并为崩岗的预防和治理提供新的理论依据。     

不同覆盖方式对旱作农田土壤碳氮含量及玉米产量的影响

设置垄膜沟播(R)、平作全覆膜(P)和平作秸秆覆盖(S)3种不同覆盖栽培模式,以传统平作(CK)为对照,通过3 a大田定位试验,研究不同覆盖方式对农田土壤碳氮及其组分变化、玉米干物质积累和籽粒产量的影响。结果表明:连续覆盖3 a后,R和P处理土壤有机碳和全氮含量及储量均呈逐渐下降趋势,而S处理则呈上升趋势且每年的增幅逐渐增大;各处理0～40 cm土层土壤有机碳储量均表现为S>R>P>CK,全氮储量表现为S>CK>R>P,S处理有机碳和全氮储量分别较CK提高3.4%和7.5%;与CK相比,R和P处理可提高土壤碳氮比,在0～20 cm土层平均分别提高7.9%和9.6%(P<0.05),而S处理0～20 cm土层土壤碳氮比平均降低了9.9%(P<0.05);各覆膜处理(R和P)均较CK显著降低了0～40 cm土层土壤可溶性有机碳(DOC)和土壤可溶性有机氮(DON)含量,而S处理较CK处理0～60 cm土层DOC和DON含量2 a平均均提高6.2%;各处理收获期硝态氮含量在0～100 cm剖面中的垂直分布与CK无明显差异;各处理土壤铵态氮含量均...     

橡胶树HbREF3基因的克隆及功能初步分析

橡胶延伸因子（REFs）是橡胶粒子上的一种主要膜蛋白,在橡胶生物合成途径中具有延伸橡胶烃和稳定橡胶粒子等重要作用。对橡胶树不同组织的转录组测序发现,HbREF3在胶乳中具有特异性的高表达,且其在HbREFs基因家族中表达水平也相对较高,仅次于表达丰度最高的HbREF1。HbREF3的开放阅读框为528 bp,编码175个氨基酸,对应的蛋白相对分子质量为19.62 kDa,理论等电点（pI）为5.28。系统进化树分析表明,HbREF3与橡胶树其他HbREFs虽均属于分组Ⅰ,但与HbREF1明显属于不同分支。HbREFs均含有REF保守结构域,但在保守motif的分布上,不同HbREFs蛋白含有保守motif数量不等,HbREF3比HbREF1多了一个motif。生信预测分析表明,该蛋白属于亲水性蛋白,无跨膜结构域,具有14个磷酸化位点。亚细胞定位分析发现HbREF3蛋白定位在内质网上,推测其可能参与橡胶粒子的形成和胶乳的再生。本研究结果为进一步阐明HbREF3基因在橡胶树胶乳再生中的作用机制奠定了基础。     

高温和干旱胁迫对马铃薯生长的影响及响应机制研究进展

全球气候变暖已成为当今世界重要的环境问题之一,对植物生长发育造成严重影响。马铃薯性喜冷凉,为浅根系作物,高温、干旱是马铃薯生长过程中面临的主要非生物胁迫,马铃薯生长发育与生理代谢直接受到其影响。笔者讨论了当前高温和干旱耐受性的鉴定方法,从马铃薯植株形态特征、细胞生理生化变化、分子水平响应等方面系统概述了马铃薯对高温和干旱胁迫的响应机制。从选育耐热抗旱新品种、应对高温干旱的栽培调控技术及基因工程等方面论述了提高马铃薯耐热抗旱的途径和措施,为马铃薯高温干旱研究提供理论参考,并对未来马铃薯耐高温和干旱研究方向和发展趋势进行了展望。     

Mapinfo在全国营造林综合核查中的应用

尝试性地将地理信息软件Mapinfo应用到全国营造林核查工作中。对应用Mapinfo地理信息软件,生成造林地块属性数据和空间数据进行了探讨,同时利用生成的数据对两期造林地块进行核查分析。     

无人机在林业调查中的应用实验

通过实验,研究了无人飞机在林业调查中的应用技术。整个实验完成了从数据获取、数据处理、与实测数据对比、分析试验数据误差、寻找试验误差原因的全过程,论证了无人机在林业调查中应用的可行性。     

Discovery,Isolation,Identification and Characterization of Novel Non-ribosomal Peptide Antibacterial Active Substances in Bacillus

The aim of this study was to search for novel non-ribosomal peptide antimicrobial substances based on the screening of bacterial secondary metabolites.The bacteria isolated from soil,sea water and common marine organisms in Yantai coastal area were isolated and purified.E.coli ATCC 25922 and Staphylococcus aureus ATCC 29213 were selected as indicator bacteria,and E.coli B2 (bla_NDM-5+mcr-1) and methicillin-resistant Staphylococcus aureus (MRSA) T144 were used as indicator for secondary screening.The genome was extracted and the PCR products were sequenced to determine the active species.The secondary metabolites of bacteria were extracted by organic extraction,purified by gel chromatography and preparative liquid chromatography,and purity was detected by analytical liquid chromatography.The results of sequencing showed that the active strain belonged to Bacillus amyloliquefaciens sp.,and was named as Bacillus amyloliquefaciens 9-14 (active bacterium 9-14).The results of antibacterial test showed that the metabolites of active bacterium 9-14 had high inhibitory effect on Staphylococcus aureus ATCC 29213,MRSA T144,E.coli ATCC 25922 and E.coli B2.The metabolites of active bacterium 9-14 were cyclic lipopeptides composed of amino acid chains,which belonged to the derivatives of ibuprofen.The biological characteristics and antibacterial spectrum of the metabolites of active bacterium 9-14 were studied.The results showed that the metabolites of active bacterium 9-14 had good thermal stability and acid-base stability.And the antibacterial activity of the antibacterial substance treated with trypsin,pepsin,protease K and papain was not significantly weakened and had good stability.The antibacterial substance also had inhibitory effect on Staphylococcus aureus and E.coli,but had no activity against Pseudomonas aeruginosa,Klebsiella pneumoniae,Enterococcus faecalis and Bacillus cereus.In this study,a new antibacterial substance was obtained,which could be used as the precursor of antibacterial drugs,and could provide certain reference for food safety and disease control.