日本骈文述略(下)

日本骈文的发展,一直延续到十二世纪。而菅原道真、纪谷长雄和三善清行可以代表前一个时代,而与上述三人相差二三十年的纪贯之,则属于后一个时代。     

Hybrid capillary-inserted microfluidic device for sheathless particle focusing and separation in viscoelastic flow

A novel microfluidic device which consists of two stages for particle focusing and separation using a viscoelastic fluid has been developed. A circular capillary tube was used for three-dimensional particle pre-alignment before the separation process, which was inserted in a polydimethylsiloxane microchannel. Particles with diameters of 5 and 10 μm were focused at the centerline in the capillary tube, and the location of particles was initialized at the first bifurcation. Then, 5 and 10 μm particles were successfully separated in the expansion region based on size-dependent lateral migration, with ∼99% separation efficiency. The proposed device was further applied to separation of MCF-7 cells from leukocytes. Based on the cell size distribution, an approximate size cutoff for separation was determined to be 16 μm. At 200 μl/min, 94% of MCF-7 cells were separated with the purity of ∼97%. According to the trypan blue exclusion assay, high viability (∼90%) could be achieved for the separated MCF-7 cells. The use of a commercially available capillary tube enables the device to be highly versatile in dealing with particles in a wide size range by using capillary tubes with different inner diameters.     

论大学校园文化中的公寓文化建设

公寓文化是校园文化的重要组成部分。目前在校园文化特别是公寓文化建设中存在着一些问题,如学校对公寓文化建设重视不够,公寓文化活动仍处于自发性和盲目性状态,缺乏有效的管理监督机制,内涵相对贫乏,网络文化的消极影响严重等。高校应加强对学生公寓的管理,在提升公寓后勤管理队伍的整体素质的同时,通过加强公寓硬件、精神文明、管理服务等方面的建设,营造一个优秀健康、和谐向上的大学生公寓文化氛围,促进大学生的全面健康发展。     

贵州金沙方言与普通话声母之对比

金沙方言属于西南官话川黔片成渝小片,虽然其基本特点与普通话一致性较高,但其语音、词汇、语法与普通话都存在一定的差异。就语音方面的声母看,两者共同的声母有17个,普通话特有的声母有5个,金沙方言特有的声母有3个。金沙方言特有的声母与普通话有比较复杂的对应关系,厘清这种对应关系,对于金沙方言区的人学习和推广普通话具有一定现实意义。     

大学生英语口语学习困境与对策

欠发达地区新建地方高校的大学生英语口语学习始终难以克服本土化困境,如语言环境差、高中英语学习的惯性、特殊的心理障碍、教育评价系缺失等不利因素一直制约着他们英语口语学习成效的提高.大学生们只有针对这些在在的问题,有针对性地加以解决,才能提高英语口语的交际能力.     

茶树中咖啡酰辅酶A氧甲基转移酶的基因克隆及其催化活性研究(英文)

目的:从茶树中克隆一种可以催化表没食子儿茶素没食子酸酯(EGCG)生成甲基化EGCG的酶——咖啡酰辅酶A氧甲基转移酶(CCo AOMT),实现甲基化EGCG的酶学合成,为甲基化EGCG的进一步开发利用提供理论依据和技术指导。创新点:本研究首次从茶树中克隆了一条CCo AOMT基因组序列;分析了CCo AOMT基因在不同茶树品种和不同成熟度茶鲜叶中的基因表达规律;证明了CCo AOMT具有催化合成甲基化EGCG的生物活性。方法:采用聚合酶链式反应(PCR)和序列分析获得CCo AOMT的编码序列和基因组序列;采用高效液相色谱-四级杆-飞行时间串联质谱技术(HPLC-QTOF-MS)分析酶促反应生成的甲基化EGCG产物(图4);采用实时荧光定量PCR分析CCo AOMT基因的表达差异(图5)。结论:本研究从茶树中克隆了CCo AOMT基因的编码序列(738 bp)和基因组序列(2678 bp),明确了该基因具有4个内含子和5个外显子;揭示了CCo AOMT可以催化EGCG生成EGCG4"Me、EGCG3"Me和EGCG3’Me等多种甲基化产物;证明了CCo AOMT具有催化生成甲基化EGCG的活性;并发现该基因的表达量高低与茶鲜叶的成熟度呈正相关关系。     

海洋科技期刊新时代办刊优化策略分析

新时代科技期刊承担着以科技成果的应用传播服务于实现现代化伟大事业的使命,面临着更广阔的发展空间。文章分析海洋科技期刊当前面临的国内外形势,明确了新时代任务,提出学科出版的时代理念和学科期刊的办刊优化方法。分别从打造顶级期刊、创建专业特色期刊、发挥行业合力作用、研发优化出版方法4方面探讨了具备一流引领性和话语权的策略;从聚焦学科前沿、驱动行业发展和科学普及应用3方面探讨提供一流影响力和服务能力的策略。     

Effect of microcystin-LR on protein phosphatase 2A and its function in human amniotic epithelial cells

Due to their toxicity, the increased distribution of microcystins (MCs) has become an important worldwide problem. MCs have been recognized as inhibitors of protein phosphatase 2A (PP2A) through their binding to the PP2A catalytic subunit. However, the exact mechanism of MC toxicity has not been elucidated, especially concerning the cellular response and its autoregulation. To further dissect the role of PP2A in MC-induced toxicity, the present study was undertaken to determine the response of PP2A in human amniotic epithelial (FL) cells treated with microcystin-LR (MCLR), one of the MC congeners. The results show that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity, and a high-dose treatment of MCLR for 24 h decreased the activity of PP2A, as expected. The increased mRNA and protein levels of the PP2A C subunit may explain the increased activity of PP2A. Furthermore, MCLR altered microtubule post-translational modifications through PP2A. These results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity of MCLR.     

Cloning and efficient expression of <Emphasis Type="Italic">Bacillus sp.</Emphasis> BH072 <Emphasis Type="Italic">tasA</Emphasis> gene in <Emphasis Type="Italic">Escherichia coli</Emphasis>

The Bacillus strain BH072 isolated from a honey sample showed strong antifungal activity against phytopathogen. Gene cloning test demonstrated that the strain had a tasA gene encoding an antifungal TasA protein. Although the wild strain simultaneously produced various antifungal substances, only the physicochemical property and antifungal activity of TasA protein were unclear due to the difficulty in extraction. In this study, tasA gene encoding the protein from Bacillus sp. BH072 was amplified by using the polymerase chain reaction (PCR) method and cloned into pET 28a (+) vector, and then expressed in host cells Escherichia coli BL21 (DE3). The expressed proteins were collected by centrifugation and ultrasonic treatment, and then purified by using nickel-nitrilotriacetic acid (Ni-NTA) metal affinity column and dialysis methods. The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test showed that an expected protein band appeared with a size of 31 kDa. The expressed products possessed antifungal activity against the phytopathogenic indicator strain Botrytis cinerea. A genetically engineered strain tasA of E. coli was established in this study which can efficiently express Tas A protein.     

AtHsfAla 对拟南芥幼苗在干旱中生理指标的影响

以过量表达 AtHsfAla 及 AtHsfAla 基因沉默的转基因植株为材料,通过控制土壤水分进行干旱处理,结果显示,过量表达型干旱处理后的存活率最大,而基因沉默型最小,表明 AtHsfA1a 能增强植物的抗旱性。为了从生理水平研究 AtHsfA1a 提高抗旱性的机制,研究发现过量表达型的叶片相对含水量和叶绿素含量最高,而沉默型最低。不同基因型植株的 H2 O2和 MDA 的含量正好相反,说明 AtHsfA1a 通过保护细胞膜而减小细胞所受氧化伤害来提高抗旱能力。