带分流叶片离心泵研究现状与发展

分析了低比转速离心泵水力性能方面存在的问题，阐述了低比转速离心泵水力设计主要方法，如加大流量设计法、无过载设计法、面积比设计法、偏置短叶片设计法，并就其相互关系进行了比较，着重分析介绍了国内外带分流叶片低比转速离心泵的研究成果和研究现状，最后对带分流叶片离心泵研究趋势做出了展望。     

以冻融法快速纯化高活力基因工程Taq DNA聚合酶

用含有TaqDNA聚合酶基因的pTaq表达质粒转化E.coli DH5α菌株，IPTG诱导表达Taq DNA聚合酶，利用该酶的热稳定性，反复2次－70℃，75℃交替冻融以裂解细胞释放胞浆；以高速离心除去冻融变性的细胞碎片及核酸蛋白的复合物以达到快速纯化Taq DNA聚合酶的目的。PCR扩增反应和SDS－PAGE分析表明所制备的Tap DNA聚合酶的纯度，活力，敏感性，特异性均达到试验要求。该方法具有快速简便的优点。     

变铅青链霉菌DNA的研究——Ⅱ.位点特异性降解与DNA修饰的关系

变铅青链霉菌的DNA上存在着一种异常的修饰,使其在含有微量Fe~(++)的缓冲液中电泳时,双链DNA遭到降解。DNA的切割是位点特异性的。与已知修饰特征的DNA进行同步试验发现,变铅青链霉菌的这种特异性修饰与目前所发现的修饰系统(如DNA甲基化)均不相同,很可能是一种新的修饰系统。     

Extensive dispersal of Roanoke logperch (Percina rex) inferred from genetic marker data

The dispersal ecology of most stream fishes is poorly characterised, complicating conservation efforts for these species. We used microsatellite DNA marker data to characterise dispersal patterns and effective population size (N_e) for a population of Roanoke logperch Percina rex, an endangered darter (Percidae). Juveniles and candidate parents were sampled for 2 years at sites throughout the Roanoke River watershed. Dispersal was inferred via genetic assignment tests (ATs), pedigree reconstruction (PR) and estimation of lifetime dispersal distance under a genetic isolation‐by‐distance model. Estimates of N_e varied from 105 to 1218 individuals, depending on the estimation method. Based on PR, polygamy was frequent in parents of both sexes, with individuals spawning with an average of 2.4 mates. The sample contained 61 half‐sibling pairs, but only one parent–offspring pair and no full‐sib pairs, which limited our ability to discriminate natal dispersal of juveniles from breeding dispersal of their parents between spawning events. Nonetheless, all methods indicated extensive dispersal. The AT indicated unrestricted dispersal among sites ≤15 km apart, while siblings inferred by the PR were captured an average of 14 km and up to 55 km apart. Model‐based estimates of median lifetime dispersal distance (6–24 km, depending on assumptions) bracketed AT and PR estimates, indicating that widely dispersed individuals do, on average, contribute to gene flow. Extensive dispersal of P. rex suggests that darters and other small benthic stream fishes may be unexpectedly mobile. Monitoring and management activities for such populations should encompass entire watersheds to fully capture population dynamics.     

转基因植物非预期效应检测评价技术的发展

检测和评价转基因植物非预期效应是转基因植物安全评价不可或缺的重要内容之一。介绍了转基因植物非预期效应的定义、成因及其检测评价技术的发展，指出了转基因植物非预期效应检测评价技术的难点和存在的问题。阐述了基因芯片分析技术在检测和评价转基因植物非预期效应中的应用前景，特别介绍了转基因植物在不同发育阶段和生长条件下差异表达基因的分布模型，并提出了利用基因芯片分析技术，从差异基因到代谢途径，再到非预期效应的转基因植物安全评价模式。这一评价模式可为今后创建高效、全面、客观、公正的转基因植物非预期效应检测和评价技术提供可能的实验模型和理论依据。     

盐藻DNA对水稻幼苗在低盐中生长的影响

[目的]分析盐藻DNA对水稻幼苗在低盐中生长的影响。[方法]将刚萌发的水稻幼苗根系浸入5 mg/L盐藻DNA溶液中培养2d,以蒸馏水培养为对照,处理后的水稻幼苗栽于含有氯化钠3 g/L的MS培养液中培养,分析盐藻DNA对水稻幼苗在低盐中生长的影响。[结果]水稻幼苗用5 mg/L盐藻DNA处理后,在含氯化钠3 g/L的MS培养液中培养15 d,其平均株重为150.7 mg,比对照增加了10.3%;平均株高为15.28 cm,比对照增加了6.1%;平均存活率为45.0%,比对照增加了125.0%;平均根数为7.15条,比对照减少了2.8%;平均根长为3.83 cm,比对照缩短了8.4%。说明盐藻DNA提高了水稻幼苗的耐盐适应性。[结论]盐藻DNA可提高水稻的耐盐适应性。     

一种用于桑RAD-Seq高通量测序的基因组DNA提取方法

[目的]筛选一种能够得到高质量桑树基因组DNA的方法。[方法]采用天根试剂盒法(Plant Genomic DNA Kit离心柱型),并稍加改进,从11个桑种的新鲜嫩叶中提取DNA。[结果]该方法简单快速,不需要复杂仪器,且能有效地除去桑叶中的多糖、多酚、蛋白质等杂质,得到的DNA能够满足RAD-Seq高通量的测序要求。[结论]建立了一种用于桑RAD-Seq高通量测序的基因组DNA提取方法。     

DNA折纸术的研究进展

为了帮助广大研究者在短时间内了解DNA折纸术的最新研究现状,掌握DNA折纸术相关软件的应用,本论文将DNA折纸术的相关内容进行了归纳。首先介绍了DNA折纸术的起源与基本原理;然后综述了近几年国内外的研究进展与取得的成果;接下来对DNA折纸术相关软件-Tiamat和Cadnano的应用和功能进行了简单的介绍,并对不同的软件进行了比较;最后对DNA折纸术的应用前景进行了展望。DNA折纸术虽然取得了一定的研究进展,但其未来的发展和应用前景将更广阔。     

小型猪复合麻醉剂及其特异性颉颃剂交互作用对大鼠不同脑区iNOSmRNA转录的影响

为研究小型猪专用复合麻醉剂（XFM）及其特异性颉颃剂交互应用对大鼠不同脑区iNOS mRNA转录的影响,将48只SD大鼠随机分为生理盐水对照组（C）和XFM与颉颃剂交互作用组（MJ）,MJ组分为早期交互（MJ1、MJ2）和晚期交互（MJ3、MJ4）2个亚组。各组大鼠到达预定时间点后分别采取脑组织,应用实时荧光定量PCR技术检测各组织中iNOS mRNA表达量。结果显示,XFM及其特异性颉颃剂交互应用时,大脑、小脑、海马、脑干和丘脑中iNOS mRNA转录均受到显著抑制（P〈0.01）,虽能逐渐回升,但在试验选取时间点内只有小脑与海马中iNOS mRNA转录恢复正常。结果表明,XFM及其特异性颉颃剂在交互作用时能够显著抑制中枢神经系统中iNOS mRNA的转录,部分脑区可以完全恢复,这可能与XFM及其特异性颉颃剂交互作用机制有关。     

Comparison of DNA probe test and cultivation methods for detection of Mycobacterium avium subsp paratuberculosis in caprine and ovine faeces

OBJECTIVE: To compare a DNA probe test with two cultivation methods for the detection of Mycobacterium avium subsp paratuberculosis in goat and sheep faeces. DESIGN: Comparison of the results of the three methods with histological examination as the reference standard. PROCEDURE: Faecal specimens were obtained from goats and sheep originating from flocks known to be affected with paratuberculosis and tested for Mycobacterium avium subsp paratuberculosis with a DNA probe test and two cultivation methods (old conventional culture and new double incubation method in Herrold's and Lowenstein-Jensen medium). RESULTS: In goats, the sensitivity of the various tests were for the DNA probe test 17.2%, for the double incubation culture method 25.4% and for the old conventional culture method 22.8% using the histopathological results as reference. In sheep the sensitivity of the various tests were for the DNA probe test 13.2%, for the double incubation culture method 8.8% and for the old conventional culture method 5.9% using the histopathological results as reference. The specificity of the above tests was 100% in goats and sheep and the specificity of the double incubation culture method in goats was 91%. CONCLUSIONS: The DNA probe test is a rapid and specific test that could be used in a control program if the sensitivity of the test were improved and possibly in combination with another test.