Ecological notes of the alien species Godiva quadricolor (Gastropoda: Nudibranchia) occurring in Faro Lake (Italy)

The first record from Sicily of the introduced facelinid nudibranch Godiva quadricolor allowed the detection of trophic relationships with the polycerid Polycera hedgpethi, another non-native nudibranch, and with two bryozoan species, namely the naturalized Cheilostomatida Bugula neritina and the cryptogenic Ctenostomatida Amathia verticillata. The settlement of both nudibranchs was presumably promoted by a trophic shift of P. hedgpethi from the natural prey B. neritina towards the largely available and not exploited A. verticillata. This short food web, without evident links with native fauna and having G. quadricolor as the top predator, is described. A DNA barcoding approach was used to confirm the identity of this facelinid species and to explore the possible genetic divergence occurring among the samples analysed.     

基于DNA-AuNCs的荧光传感新方法灵敏检测胰蛋白酶活性

以DNA模板金纳米簇(DNA-AuNCs)作为荧光探针,发展了一种灵敏检测胰蛋白酶活性的荧光分析新方法.在胰蛋白酶存在条件下,牛血清白蛋白水解成多肽片段,释放出游离的半胱氨酸残基.半胱氨酸残基与金纳米簇通过Au-S键形成非荧光的配合物,导致金纳米簇的荧光强度显著降低.该方法对胰蛋白酶的线性检测范围为0.1～2.0mg/L,检出限为20μg/L(R_(SN)=3).此外,该方法被成功应用于人血清样品中胰蛋白酶含量的测定.     

一种三维DNA构象的交互式参数化模拟方法

提出一种适用于移动平台的交互式参数化DNA三维动态模拟方法.依据不同的DNA模式参数,利用基于自然特征的AR识别技术和曲线,直观形象地展示DNA的多种三维构象,动态模拟碱基互补配对、碱基对边堆叠边螺旋、 DNA复制的边解旋边半保留半不连续复制等微观过程.研发DNA三维动态模拟原型系统,实验结果表明,通过视、听、触、实物等多通道交互,有利于用户随时随地自主使用,增强用户对DNA知识的理解、掌握,引导用户进行更深层次的思考,提高知识的传递效率.     

Photosensitized splitting of cis-syn 1,3-dimethyluracil dimer by tryptophan and its peptides

Photosensitized splitting of cis-syn 1,3-dimethyluracil dimer by tryptophan (Trp) and its peptides (Trp-Tyr and Trp-Phe) is studied by fluorescence quenching experiments and irradiation experiments.It reveals that 1,3-dimethyluracil dimer is mainly split by e?-?aq resulting from two-photon ionization of Trp and its peptides under irradiation with light (λ>290 nm).Moreover,the excited singlet state of Trp and its peptides can transfer an electron to the dimer,which splits and gives two pyrimidines.In addition,because of its lower oxidative potential,the excited triplet state of Trp-Tyr can also split the dimer via transfering an electron to the dimer.     

基于DNA序列的信息隐藏

研究了以DNA序列为载体的信息隐藏,提出了一个信息隐藏算法.该算法首先将秘密信息经预处理、编码、调制变成一维随机DNA序列;然后由一个随机数序列决定隐藏信息在载体的高复杂性区域的位置;最后在隐藏信息的位置,秘密信息字符替代载体字符.由该算法实现的信息隐藏既具有一定的稳健性和安全性,又符合生物学意义.实验结果也证明了该算法的有效性.     

诺氟沙星——铽（Ⅲ）与核酸的相互作用研究及其应用

研究了诺氟沙星—铽(Tb^3 )络合物与核酸(DNA)的相互作用，据此建立了核酸的测定方法，讨论了诺氟沙星—铽与DNA分子之间的结合方式。     

Improving the thermal stability of lactate oxidase by directed evolution

Lactate oxidase is used in biosensors to measure the concentration of lactate in the blood and other body fluids. Increasing the thermostability of lactate oxidase can significantly prolong the lifetime of these biosensors. We have previously obtained a variant of lactate oxidase from Aerococcus viridans with two mutations (E160G/V198I) that is significantly more thermostable than the wild-type enzyme. Here we have attempted to further improve the thermostability of E160G/V198I lactate oxidase using directed evolution. We made a mutant lactate oxidase gene library by applying error-prone PCR and DNA shuffling, and screened for thermostable mutant lactate oxidase using a plate-based assay. After three rounds of screening we obtained a thermostable mutant lactate oxidase, which has six mutations (E160G/V198I/G36S/T103S/A232S/F277Y). The half-life of this lactate oxidase at 70 °C was about 2 times that of E160G/V198I and about 36 times that of the wild-type enzyme. The amino acid mutation process suggests that the combined neutral mutations are important in protein evolution. Received 15 September 2006; received after revision 21 October 2006; accepted 2 November 2006     

DNA聚合酶链反应鉴测梨树火疫病

对细菌Ｅ．ａｍｙｌｏｖｏｒａ，Ｅ．ｈｅｒｂｉｃｏｌａ和Ｐｓｅｕｄｏｍｏｎａｓｓｙｒｉｎｇａｅ的ＤＮＡ提纯，并通过聚合酶链反应，发现引物Ｂ＿５等可用以有效地鉴别Ｅ．ａｍｙｌｏｖｏｒａ．对Ｅ．ａｍｙｌｏｖｏｒａ细胞培养液直接稀释，加清洁剂处理后进行聚合酶链反应（ＰＣＲ）．据引物Ｂ＿５测定，得到清晰而强烈的相同的ＤＮＡ分子电泳光带，可有效反应测定５００个细菌细胞；用引物Ｂ＿５和Ｂ＿６进一步测定细菌Ｅ．ａｍｙｌｏｖｏｒａ。Ｅ．ｈｅｒｂｉｃｏｌａ和Ｐ．ｓｙｒｉｎｇａｅ，从Ｅ．ｈｅｒｂｉｃｏｄａ反应获得一个电泳光谱，从Ｐ．ｓｙｒｉｎｇａｅ获得３个泳谱；用引物Ｂ＿５和Ｂ＿７与细菌Ｅ．ａｍｙｌｏｖｏｒａ和Ｐ．ｓｙｒｉｎｇａｅ反应，从Ｅ．Ｅ．ａｍｙｌｏｖｏｒａ得到两条相同光带，从Ｐ．ｓｙｒｉｎｇａｅ反应获得了相似的带谱分布。     

单核苷酸多态性研究进展及其在法庭科学中的应用

单核苷酸多态性(Singlenucleotidepolymorphism,SNP)是人类基因组中单个碱基的变异,其最低基因频率不低于1%,是倍受关注的第三代多态性遗传标记,为法医物证检验提供了新的方向,本文就其研究最新进展、应用及检测手段作一综述.