Electrophysical analysis of Escherichia coli cell damage caused by silver ions]

The influence of Ag+ (0.5-10 microM) on Escherichia coli K-12 cells was studied by electrophoresis and electro-orientation spectroscopy methods. It was shown that the pH-dependency of the cell electrokinetic potential (phosphate-citrate buffer with ion strength 0.02) practically didn't changed after Ag+ treatment, but in low-conductive media electrophoretical mobility of intact and inactivated by heat (70 degrees, 15 min) cells gradually decreased as the Ag+ concentration increased. It was due to the Ag+ adsorption on the cell surface and could not be used for the definite characterization of the cell damage. The high-frequency decrease in the cell electro-orientation spectrum shifted to the region of lower frequencies, K+ was excreted by cells, slight raise of the medium pH occurred and significant changes of cell osmotic properties were observed as a result of Ag+ action. All these changes showed the disturbance of barrier properties of the cytoplasmic membrane. Besides the damaging action of Ag+ on cell membranes increased with the decrease of pH and decreased after the addition of Mg2+, Ca2+ and Sr2+ in low concentrations.     

Stereological analysis of ultrastructural changes in cardiomyocytes during adriblastina-induced cardiomyopathy

Both single and graded administration of an anthracycline antibiotic adriablastine at a dose of 20 mg/kg to white rats have resulted in cardiomyocyte volume decrease, dystrophia and lysis of myofibrils, and reduction of mitochondrial surface density volume. Accumulations of myelin bodies of different configuration and diffuse myolysis were observed. Myelin bodies and diffuse myolysis of cardiomyocytes in adriablastine-induced cardiomyopathy are believed to be a morphological sign of lipid peroxidation.     

Immunomodulating effect of cyclophosphamide on cytotoxic activity of rat and mouse splenocytes

The goal of this work consisted in study of the immunomodulating action of the cytostatic drug cyclophosphamide (CP) on the natural cytotoxic activity of rat and mice splenocytes. The cytotoxicity of effector cells (EC) with respect to monolayer cell lines of the Zajdela rat hepatoma and the HTC rat hepatoma and of the MH-22a mouse hepatoma was determined with the aid of morphometric analysis. CP at a dose of 100 mg/kg 48 h after administration to animals has been shown to produce an immunomodulating effect on cytotoxicity of splenocytes—a suppressive one with respect to cell-targets (CT) of Zajdela hepatoma and an immunopotentiating one with respect to CT of HTC and MH-22 hepatomas. Possible mechanisms of the CP immunopotentiating action are discussed.     

构建基于CRISPR/Cas9技术敲除ALOX5的质粒

旨在利用CRISPR/Cas9技术构建敲除花生四烯5-脂氧合酶基因(Arachidonate 5-lipoxygenase gene,ALOX5)的重组质粒。设计合成3对靶向敲除ALOX5第六外显子的sgRNA,将其分别插入到CRISPR/Cas9质粒骨架pX458载体中,转化感受态大肠杆菌DH5α后挑取克隆,通过测序评估重组质粒是否构建成功。将构建好的重组质粒转染293T细胞,在荧光显微镜下观察转染效果,挑取转染成功的细胞,用试剂盒提取转染细胞基因组DNA,PCR扩增含敲除位点的DNA片段,用测序技术获得核苷酸序列,用DNAStar软件分析转染细胞中ALOX5基因敲除情况。测序结果表明2对双链sgRNA寡核苷酸已插入质粒,且序列正确,靶向ALOX5基因的重组质粒pX458-sgRNAs-ALOX5构建成功。其在293T细胞中的转染效率约为50%,用一代测序法未检测到sgRNAs的切割效果。初步表明利用CRISPR/Cas9技术成功构建靶向ALOX5基因的重组质粒pX458-sgRNAs-ALOX5。     

Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates

Plant and Soil - In water-limited areas, shrubs influence biological soil crust (biocrust) composition and diversity via soil microenvironment alterations and through modifying biotic interactions...     

中国三种常见蒿属植物潜在地理分布及其主导气候因子

裂叶蒿(Artemisia tanacetifolia)、大籽蒿(Artemisia sieversiana)和艾(Artemisia argyi)是我国常见的蒿属(Artemisia)植物,其分布区域遍布全国。本文利用MaxEnt模型预测3种蒿属植物在当前气候条件以及未来两种气候情景下的潜在分布区。采用受试者工作特征曲线(receiver operating characteristic curve,ROC)检验模型精度。训练数据和测试数据的AUC值均在0.8以上,表明预测结果可靠性良好。在当前的气候条件下,裂叶蒿最适分布区主要为黄土高原、内蒙古高原和东北平原;大籽蒿的最适分布区为西藏南部谷地、横断山地区、黄土高原、内蒙古高原和东北平原;艾的最适分布区有两个,一个位于台湾岛南部,另一个为大巴山、巫山、云贵高原北部、黄土高原和东北平原南部区域。2070年RCP2.6和RCP8.5情景下,裂叶蒿及大籽蒿的高适宜区面积减小,艾的最适分布区面积增加。Jackknife检验结果表明,年均降水量是预测裂叶蒿分布最有效的气候因子,5月降水是预测大籽蒿分布的最显著的气候因子,8月水汽压对艾的影响最大。本研究结果为蒿属植物资源的合理利用提供了科学依据。