芽胞气溶胶表面滞留抗力预测模型研究

针对生物威胁的现场处置工作,建立气溶胶芽胞表面滞留抗力的智能预测模型,以准确预测环境表面芽胞污染状况,为大规模的现场洗消任务提供重要依据,有利于实现及时反应、恰当反应和准确防护的目标。以枯草杆菌芽胞为试验菌,在气溶胶实验室进行芽胞的环境因素暴露及活力测定,以模拟环境中芽胞抗力变化规律数据为依据,采用Matlab6.1软件包中的神经网络工具箱进行抗力预测模型研究。根据研究目的、模拟环境条件和数据训练的平滑曲线等特征,设定了5个输入神经元,8个隐层节点和1个输出神经元。‘tansig’、‘purelin’为传递函数,trainlm为训练函数,网络迭代100次。模型回顾预测效率达到100%,前瞻预测效率达到91%。以实验室数据为依据,利用Matlab平台中的BP神经网络建立的芽胞气溶胶表面滞留抗力预测模型能利用环境因素信息有效预测芽胞抗力。     

芽胞抗力快速弱化技术研究

以L-丙氨酸缓冲液为发芽剂,结合芬顿反应原理,观察发芽-氧化损伤效应对芽胞的杀灭效果,以期为新型炭疽疫源地净化方法的深入研究奠定基础。以腊样芽胞为试验菌,采用透射电镜、激光扫描共聚焦显微镜、活菌计数等方法观察芽胞发芽过程的超微结构、核酸含量变化,以及在芬顿反应的联合作用下发芽体的活性变化。在20~30 min的发芽过程中,芽胞核心密度降低,核心与皮质、皮质与外壁之间界限模糊,芽胞外壁和芽胞衣有破裂,通透性增加,进一步有皮质消失、细胞核与细胞质融合、细胞膜基本形成的现象;发芽体荧光强度不断增加,显示菌体中核酸的活性和含量不断增加;发芽体对化学因子的抗力明显下降,H2O2浓度为0.20 mol/L的Fenton反应系统作用60 min时,发芽体灭活可达到3.016个对数级。诱导发芽和反应的联合处理程序可显著提高芽胞的灭活水平。     

嗜铬颗粒蛋白A研究进展

嗜铬颗粒蛋白A(Chromogranin A,CGA)属于独特的酸性可溶性蛋白质家族,遍布于动物内分泌系统、神经系统和免疫系统,与其他激素和多肽共贮存、共分泌.在CGA上有许多碱性氨基酸对,成为潜在的激素原转化酶切割位点.很多切割产物已经被鉴定,其中有些具有生物学功能.近年的研究表明,在多种病理、生理状态下,CGA及其衍生片段在组织中含量升高,发挥抑制性生理功能或作为疾病诊断指标.嗜铬颗粒蛋白A的N端衍生片段在机体防御系统中的抗菌功能、在心血管系统中的抗血管收缩功能已被阐明,使其作为临床候选药物具有巨大潜力;CGA完整片段在内分泌肿瘤和神经内分泌肿瘤中含量升高,可作为内分泌肿瘤和神经内分泌肿瘤诊断指标,但其在肿瘤发生过程中的作用还未见报道.     

不同产地中华鳖的线粒体控制区序列分析及结构比较

采用PCR特异引物,扩增了两产地中华鳖（Pelodiscus sinensis）个体的mtDNA控制区（CR）及其邻近片段,测序获得了长度分别为1830bp和1630bp的序列。结合GenBank中已发表的韩国产中华鳖mtDNA的CR区序列,比较了3个产地中华鳖的CR区结构。分析显示：中华鳖不同产地mtDNA CR区DNA中的A＋T含量分别为60.5%、63.6%和64.8%,它们的5′、3′末端以及CSB1-CSB2之间均存在丰富的可变数目串联重复序列（variable numbers oftandem repeats,VNTR）。基于mtDNA CR区序列和结构分析,显示中华鳖不同产地的野生个体中存在丰富的遗传多样性。     

Numerical simulation of hemodynamics in stented internal carotid aneurysm based on patient-specific model

There is still a considerable lack of quantitative information concerning the effects of stent structures on blood flow in an aneurismal cavity. In this paper, five virtual stents with different structures and wire cross-sections were designed for incorporation into the same patient-specific aneurysm model. Computational fluid dynamics simulations were performed so as to study how these five types of stents modified hemodynamic parameters. Numerical results demonstrated that the mean flow rate in the aneurismal cavity decreased the most in the model that used a stent with a rectangular wire cross-section, and that the wall shear stresses at the dome and neck of the aneurysm decreased more in models that used a stent with a circular wire cross-section or a spiral stent with a rectangular wire cross-section compared to other models. In addition, the wall pressure on the aneurysm increased slightly after implantation of the stent in all five models. This result differs from that previously published, and may help guide the design and assist clinicians in selecting an appropriate stent for treating cerebral aneurysms.     

Structural Variants Selected during Yak Domestication Inferred from Long-Read Whole-Genome Sequencing

Structural variants (SVs) represent an important genetic resource for both natural and artificial selection. Here we present a chromosome-scale reference genome for domestic yak (Bos grunniens) that has longer contigs and scaffolds (N50 44.72 and 114.39 Mb, respectively) than reported for any other ruminant genome. We further obtained long-read resequencing data for 6 wild and 23 domestic yaks and constructed a genetic SV map of 372,220 SVs that covers the geographic range of the yaks. The majority of the SVs contains repetitive sequences and several are in or near genes. By comparing SVs in domestic and wild yaks, we identified genes that are predominantly related to the nervous system, behavior, immunity, and reproduction and may have been targeted by artificial selection during yak domestication. These findings provide new insights in the domestication of animals living at high altitude and highlight the importance of SVs in animal domestication.     

玉米黄尾球跳甲的发生与防治

调查研究玉米黄尾球跳甲Sphaeroderma apicaleBaly的自然种群动态、自然种群生命表并对其药剂防治策略进行探讨。结果表明:玉米黄尾球跳甲在湖北宜昌1年发生1~2代,以成虫和蛹越冬。越冬代成虫4月中旬始现于田边的杂草,5月上旬迁入大田。百株成虫高峰出现在6月15日和8月7日;性比为0.491;卵始现于5月19日,产卵高峰出现在6月18日;平均卵量123.5粒,单雌最大卵量212粒;6月22日出现最高百株幼虫量。自然种群增长指数(I)为16.20。在发生盛期、高峰期、盛末期,玉米黄尾球跳甲被异角短胸姬小蜂Hemiptarsenus variconisGirault的寄生率分别为14.6,33.6和77.0%。马.辛硫磷1 000倍液和毒死蜱1 000倍液是防治玉米黄尾球跳甲比较理想的农药,校正防治效果分别为76.3%和66.5%;卵和1、2龄幼虫对化学药剂敏感性高,3龄幼虫对化学药剂敏感性低。结合以上的研究,提出玉米黄尾球跳甲的防治策略。     

云南抚仙湖沉水植物分布及群落结构特征

2005年6～7月对抚仙湖沉水植物进行了调查。共采集到沉水植物12种。沉水植物在抚仙湖沿岸浅水区均有不同程度的分布,主要分布在北岸、南岸、河口以及湖湾。分布区内平均水深4．27m,平均透明度2．96m。优势种为黑藻、穗状狐尾藻、篦齿眼子菜、金鱼藻和苦草,其优势度分别为59．08％、54．47％、54．26％、48．71％和48．30％,占群落总优势度的65．19％。根据优势种及组成特征,可将沉水植物群落分为11个类型。全湖沉水植物分布区面积318．8hm^2,资源量19502．79t,平均生物量6118g/m^2。2005年与1980年前后和2003年的调查结果相比,抚仙湖沉水植物、生物量和分布范围显著增加。     

Expression of Discoidin Domain Receptor 2 (DDR2) Extracellular Domain in Pichia Pastoris and Functional Analysis in Synovial Fibroblasts and NIT3T3 Cells

Discoidin domain receptor 2 (DDR2) is a kind of protein tyrosine kinases associated with cell proliferation and tumor metastasis, and collagen, identified as a ligand for DDR2, up-regulates matrix metallloproteinase 1 (MMP-1) and MMP-2 expression in cellular matrix. To investigate the roles of DDR2 in destruction of cartilage in rheumatoid arthritis (RA) and tumor metastasis, we tried to express extracellular domain of DDR2 fused with a His tag to increase protein solubility and facilitate purification (without signal peptide and transmembrane domain, designated DR) in Pichia pastoris, purify the expressed protein, and characterize its function, for purpose of future application as a specific DDR2 antagonist. Two clones of relative high expression of His-DR were obtained, After purification by a Ni-NTA (nitric-tri-acetic acid) chromatographic column, soluble fused His-DR over 90% purity were obtained. Competitive binding inhibition assay demonstrated that expressed His-DR could block the binding of DDR2 and natural DDR2 receptors on NIT3T3 and synovial cell surfaces. Results of RT-PCR, Western blotting, and gelatinase zymography showed that His-DR was capable of inhibiting MMP-1 and MMP-2 secretion from NIT3T3 cells and RA synoviocytes stimulated by collagen II. For MMP-1, the inhibitory effect was displayed at the levels of mRNA and protein, whereas for MMP-2 it was demonstrated at the level of protein physiological activity. All these findings suggested that the fused expressed His-DR inhibited the activity of natural DDR2, and relevant MMP-1 and MMP-2 expression in synoviocytes and NIH3T3 cells provoked by collagen II. Wei Zhang and Tianbing Ding equally contributed to this work.