SMRT Sequencing of Long Tandem Nucleotide Repeats in SCA10 Reveals Unique Insight of Repeat Expansion Structure

A large, non-coding ATTCT repeat expansion causes the neurodegenerative disorder, spinocerebellar ataxia type 10 (SCA10). In a subset of SCA10 patients, interruption motifs are present at the 5’ end of the expansion and strongly correlate with epileptic seizures. Thus, interruption motifs are a predictor of the epileptic phenotype and are hypothesized to act as a phenotypic modifier in SCA10. Yet, the exact internal sequence structure of SCA10 expansions remains unknown due to limitations in current technologies for sequencing across long extended tracts of tandem nucleotide repeats. We used the third generation sequencing technology, Single Molecule Real Time (SMRT) sequencing, to obtain full-length contiguous expansion sequences, ranging from 2.5 to 4.4 kb in length, from three SCA10 patients with different clinical presentations. We obtained sequence spanning the entire length of the expansion and identified the structure of known and novel interruption motifs within the SCA10 expansion. The exact interruption patterns in expanded SCA10 alleles will allow us to further investigate the potential contributions of these interrupting sequences to the pathogenic modification leading to the epilepsy phenotype in SCA10. Our results also demonstrate that SMRT sequencing is useful for deciphering long tandem repeats that pose as “gaps” in the human genome sequence.     

Hymeniacidon perleve associated bioactive bacterium pseudomonas sp. NJ6-3-1

Among the marine bacteria isolated from cytotoxic sponge Hymeniacidon perleve, one strain NJ6-3-1 classified as Pseudomonas sp. showed both cytotoxic and antimicrobial activities. Fatty acid analysis indicated that the bacterial strain consists mainly of C16:1, C16:0, C18:1, C18:0, C15:0, C14:0. One unusual 9,10-cyclopropane-C17:0 fatty acid, and C26:0 also constitute as major component as well as the existence of squalene, the precursor of triterpenoids. The major metabolites in the culture broth were identified as alkaloids, including diketopiperazines and indole compounds, namely 3,6-diisopropylpiperazin-2,5-dione, 3-benzyl-3-isopropylpiperazin-2,5-dione, 3,6-bis-(2-methylpropyl)-piperazin-2,5-dione, indole-3-carboxaldehyde, indole-3-caroxylic acid methyl ester, indole-3-ethanol, and quinazoline-2,4-dione.     

Lipid membrane immobilized horseradish peroxidase biosensor for amperometric determination of hydrogen peroxide

Stable films of didodecyldimethylammonium bromide (DDAB, a synthetic lipid) and horseradish peroxidase (HRP) were made by casting the mixture of the aqueous vesicle of DDAB and HRP onto the glassy carbon (GC) electrode. The direct electron transfer between electrode and HRP immobilized in lipid film has been demonstrated. The lipid films were used to supply a biological environment resembling biomembrane on the surface of the electrode. A pair of redox peaks attributed to the direct redox reaction of HRP were observed in the phosphate buffer solution (pH 5.5). The cathodic peak current increased dramatically while anodic peak decreased by addition of small amount H(2)O(2). The pH effect on amperometric response to H(2)O(2) was studied. The biosensor also exhibited fast response (5 s), good stability and reproducibility.     

Atomic force microscopy imaging and single molecule recognition force spectroscopy of coat proteins on the surface of Bacillus subtilis spore

Coat assembly in Bacillus subtilis serves as a tractable model for the study of the self-assembly process of biological structures and has a significant potential for use in nano-biotechnological applications. In the present study, the morphology of B. subtilis spores was investigated by magnetically driven dynamic force microscopy (MAC mode atomic force microscopy) under physiological conditions. B. subtilis spores appeared as prolate structures, with a length of 0.6-3 microm and a width of about 0.5-2 microm. The spore surface was mainly covered with bump-like structures with diameters ranging from 8 to 70 nm. Besides topographical explorations, single molecule recognition force spectroscopy (SMRFS) was used to characterize the spore coat protein CotA. This protein was specifically recognized by a polyclonal antibody directed against CotA (anti-CotA), the antibody being covalently tethered to the AFM tip via a polyethylene glycol linker. The unbinding force between CotA and anti-CotA was determined as 55 +/- 2 pN. From the high-binding probability of more than 20% in force-distance cycles it is concluded that CotA locates in the outer surface of B. subtilis spores.     

派盾螨科二新种(蜱螨亚纲:革螨股)

本文记述派盾螨科２新种：副变革板螨Ｇａｍａｓｈｏｌａｓｐｉｓｐａｒａｖａｒｉａｂｉｌｉｓ,ｓｐ．ｎｏｖ．和陈氏讷派螨Ｎｅｐａｒｈｏｌａｓｐｉｓｃｈｅｎｐｅｎｇｉ,ｓｐ．ｎｏｖ．。模式标本存吉林省白城市全国鼠疫布氏菌病防治基地。     

偃麦草与小偃麦染色体组构成的细胞遗传学研究Ⅱ.八倍体小偃麦与四倍体小麦杂种的减数分裂观察

在获得八倍体小偃麦“小偃7430”与二个四倍体小麦物种,硬粒小麦和提摩菲维小麦的杂种的基础上,观察了F_1的减数分裂。中期Ⅰ不仅出现许多单价体,还观察到极复杂的多价体,二个杂种平均每细胞构型分别为13.5Ⅰ+11.1Ⅱ+1.67Ⅲ+0.24Ⅳ+0.02Ⅴ+0.04Ⅵ和19.8Ⅰ+7.01Ⅱ+2.16Ⅲ+0.27Ⅳ+0.10Ⅴ+0.01Ⅵ+0.004Ⅶ。后一杂种后期Ⅰ细胞中观察到平均7.14个单价体排列于赤道板,其分裂过程显然与由交叉维系的染色体不同。对此杂种作了花药培养,得到了绿苗。讨论了以这种“8×4”杂种形成具有重建型染色体组的次级六倍体的可能性。     

黑龙江渐新世银杏大化石及其古气候和植物地理意义

首次报道我国渐新世银杏属植物叶化石。化石采自黑龙江汤原县太平川剖面宝泉岭组,角质层保存状态良好。叶为下气孔式。上表皮细胞垂周壁平直,平周壁较平。下表皮大量气孔器不规则地散布于脉间区,形成气孔带;气孔密度约为117个/mm2;气孔器为单环式,保卫细胞下陷,侧副卫细胞角质化强烈并形成乳突。当前材料的形态及显微构造特征与古近纪北半球广泛分布的铁线蕨型银杏Ginkgo adiantoides(Ung.)Heer emend.Flo-rin(auctorum multorum)基本一致。这是我国目前已知年代最新的银杏大化石记录,对于探究银杏属在我国新生代的分布、迁徙以及当时相关的古植物地理和气候环境等具有重要意义。     

偃麦草属遗传资源的应用研究

偃麦草属(Elytrigia)是小麦的野生近缘属,具有许多优良基因,是小麦的三级基因库和小麦性状改良的优异供体之一。综述了偃麦草属基因组的研究和其在小麦遗传育种中的应用。     

偃麦草与小偃麦染色体组构成的细胞遗传学研究——Ⅱ.八倍体小偃麦与四倍体小麦杂种的减数分裂观察

在获得八倍体小偃麦“小偃7430”与二个四倍体小麦物种,硬粒小麦和提摩菲维小麦的杂种的基础上,观察了F₁的减数分裂。中期Ⅰ不仅出现许多单价体,还观察到极复杂的多价体,二个杂种平均每细胞构型分别为13.5Ⅰ+11.1Ⅱ+1.67Ⅲ+0.24Ⅳ+0.02Ⅴ+0.04Ⅵ和19.8Ⅰ+7.01Ⅱ+2.16Ⅲ+0.27Ⅳ+0.10Ⅴ+0.01Ⅵ+0.004Ⅶ。后一杂种后期Ⅰ细胞中观察到平均7.14个单价体排列于赤道板,其分裂过程显然与由交叉维系的染色体不同。对此杂种作了花药培养,得到了绿苗。讨论了以这种“8×4”杂种形成具有重建型染色体组的次级六倍体的可能性。     

Determination of oxidized scytonemin in Nostoc commune Vauch cultured on different conditions by high performance liquid chromatography coupled with triple quadrupole mass spectrometry

A facile method based on high performance liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-QqQ-MS) has been established to investigate the production of the oxidized scytonemin by Nostoc commune Vauch in different environmental conditions. In optimized HPLC-ESI-QqQ-MS conditions, the oxidized scytonemin can be effectively detected in selected reaction monitoring (SRM) mode. After regression, high linearity of the calibration curve was achieved with a correlation coefficient (r ²) at 0.99. The limit of detection and limit of quantification were 0.03 and 0.10 ng mL^?1, respectively. The recovery of the oxidized scytonemin was at 76.90 %, and the relative standard deviations of inter- and intraday precisions were lower than 8.95 % (n?=?4). Subsequently, the production of the oxidized scytonemin from N. commune has been investigated in different culture conditions. High culture temperature, strong illumination intensity, and light–dark cycle (12:12 h) were found to be good for producing the oxidized scytonemin by N. commune. In short, the HPLC-QqQ-SRM-MS method is a powerful tool for comprehensive analysis of the oxidized scytonemin from N. commune, owing to its excellent selectivity and sensitivity.