不同破壁方法对活性污泥总DNA提取效果的影响

分别采用酶法、化学法、珠磨匀浆法和反复冻融法对活性污泥样品进行破壁，提取总DNA，并通过提取的核酸总量、纯度、片段分布情况、是否含有聚合酶链反应抑制剂以及基因间隔序列(ITS)扩增产物多态性等5个指标来评价不同的细胞破壁方法对活性污泥总DNA提取效果的影响。结果表明，化学法的优势最明显，提取的总量最多，大片段提取效果好，虽然杂质较多，但不影响聚合酶链反应，方法的偏倚性最小。     

一种新的彩色图像降维方法

基于内容的图像检索(CBIR)是图像检索的重要分支，而基于颜色的特征提取是CBIR的常用方法之一．如果对图像颜色的特征数提取过多、维数过大，则不利于对图像的快速匹配．本文将图像的色彩直方图作为输入向量，然后采用局部线性映射(LLE)算法对原始数据进行降维，并分别在4种色彩空间下对降维后的彩色图像进行分类．实验证明，在处理非线性数据降维时，LLE较主成分分析(PCA)具有明显的优势．     

Poly(dimethylsiloxane) based microchip for DNA electrophoresis

A novel poly(dimethylsiloxane)(PDMS) -based microchip for DNA separation through electrophoresis has been developed using a micro-electro-mechanical-system(MEMS) technology. Unlike previous hybrid PDMS microchip, one PDMS film is first created on glass support by pressing method in our microchip. Thus, increased band-broadening phenomena, arising from the material nonuniformity at the walls of microchannel, can be avoided in electrophoresis process. A low-viscosity hydroxypropylmethylcellulose-100 (HPMC-100) is used as the separation medium for fluorescent intercalator-labeled double-stranded DNA (dsDNA) fragments. Mannitol is introduced to PDMS-based microchip as a separation medium additive to enhance separation efficiency. At applied electric field strength of 150 V/cm, excellent separations of the PCR marker could be achieved with an effective separation distance of 25mm .     

基因组学与地球科学迅猛发展,古生物学进入纵深发展新时代——2017年古生物学热点回眸

 古生物学是以化石为主要研究对象,研究地质历史时期的生物界及其发展的科学,属于地球科学与生命科学之间的交叉学科。随着生命科学基因组学与地球系统科学的迅猛发展,古生物学这门古老学科进入了纵深发展的新时代,不断涌现振奋人心的研究进展与新发现。本文回顾了2017年国际古生物研究领域取得的重要进展与研究热点,并介绍了中国古生物学界2017年在早期生命、早期后口动物、古脊椎动物、古人类、古DNA以及演化古生物学等研究方向做出的重要贡献。     

Wnt/β-catenin信号途径在DDR和氧化应激中的作用

Wnt/β-catenin信号途径在调控基因表达与DNA损伤反应(DNA damage response,DDR)中具有重要作用.氧化应激是导致DNA损伤的主要原因,且可以影响Wnt信号.首先总结了Wnt/β-catenin信号途径和DDR,然后综述了Wnt/β-catenin信号途径在DDR和氧化应激中的作用及分子机制,以期为DNA修复缺陷性肿瘤提供更有效的治疗策略.     

染色体结构维持蛋白Smc5/6复合体的结构与功能

真核生物基因组DNA主要以染色体的形式存在于细胞核中，染色体结构的稳定及其动态变化对于真核生物遗传信息从亲代到子代中的准确传递和维持细胞的正常功能是必不可少的。染色体结构维持蛋白（Structure Maintenance of Chromosome，Smc）在染色体结构维持及DNA损伤修复方面发挥着关键性的作用。Smc蛋白家族包括3类：黏连蛋白（Cohesin）、凝缩蛋白（Condesin）和Smc5/6复合体（Smc5/6 complex）。Smc5/6复合体在真核生物中分布广泛且高度保守，在DNA损伤同源重组修复、DNA复制、端粒长度维持及胚胎发育中发挥重要作用。本文系统介绍了Smc5/6复合体结构特征和生物学功能领域的相关进展，为深入研究Smc5/6复合体提供理论参考。     

Diversity and dispersal history of the talitrids (Crustacea: Amphipoda: Talitridae) of Bermuda

Five taxa of talitrid amphipods were found in the archipelago of Bermuda, of which three were recorded there for the first time. Four of these are supralittoral wrack generalists: Platorchestia monodi BOLD:AAB3402, (a unique Molecular Operational Taxonomic Unit according to the Barcode Index Number system), a related species recognized by molecular methods, Platorchestia platensis BOLD:AAA2949, Mexorchestia carpenteri carpenteri BOLD:AAC1491 and Tethorchestia antillensis; and one a terrestrial leaf-litter generalist: Talitroides alluaudi. A key is provided to discriminate between the formally described talitrids of Bermuda. Dispersal mechanisms from the American continent to Bermuda were considered for all taxa based on species distributions along the North American Atlantic coast and also investigated by molecular methods, using genetic population differentiation and haplotype network analysis based on the barcode region of cytochrome c oxidase subunit I gene. For P. monodi BOLD:AAB3402 the genetic results suggest that some dispersal events occurred before human colonization of Bermuda but are equivocal about the source population and therefore the direction of dispersal. Some very recent synanthropic dispersal is possible with this species. For the other two species studied genetically, P. platensis BOLD:AAA2949 and M. c. carpenteri BOLD:AAC1491, the small population samples analysed support dispersal to Bermuda from the American mainland, before human occupation of Bermuda, although the available sample size was limited for these species. The available limited direct, non-genetic evidence supports synanthropic transport for Talitroides alluaudi. Platorchestia monodi BOLD:AAB3402 is found in the same wrack habitat as P. platensis BOLD:AAA2949 on Bermuda, apparently without interbreeding. No evidence was found that driftwood specialist talitrids had become established in Bermuda.     

Nine new species of the subgenus Stegana (Oxyphortica) from the Oriental region,with morphological and molecular evidence based on Chinese species (Diptera: Drosophilidae)

Nine new species of the subgenus Stegana (Oxyphortica) have been discovered from the Oriental Region: S. (O.) chuanjiangi Zhang and Chen, sp. nov., S (O.) dainuo Wang and Chen, sp. nov., S. (O.) dawa Zhang and Chen, sp. nov., S. (O.) laohlie Zhang and Chen, sp. nov., S. (O.) luchun Wang and Chen, sp. nov., S. (O.) mengwan Wang and Chen, sp. nov., S. (O.) triodonta Cheng and Chen, sp. nov. from southern China; S. (O.) dehiscens Cheng and Chen, sp. nov. and S. (O.) spinosa Cheng and Chen, sp. nov. from eastern Malaysia. One newly recorded species from China: S. (O.) maichouensis Sidorenko is re-described. The DNA sequences of the mitochondrial COI gene with BOLD Process ID and GenBank accession numbers are provided for the above seven new species and five known species from China: S. (O.) acutipenis Xu, Gao and Chen, S. (O.) adentata Toda and Peng, S. (O.) hirtipenis Xu, Gao and Chen, S. (O.) latipenis Xu, Gao and Chen, and S. (O.) maichouensis Sidorenko. Intra- and interspecific pairwise K-2P distances among these species are summarized and the phylogenetic relationships are reconstructed based on the neighbour-joining (NJ) analyses.

www.zoobank.org/urn:lsid:zoobank.org:pub:2FA403F6-5535-40A4-9FD0-ADB9913EDE83.     

An important functional group,benzo[1,3]dioxole,of alkaloids induces the formation of the human telomeric DNA G-quadruplex

Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.