Room Temperature Preparation of Surface-Clean Hydrogen-Doped Plasmonic Molybdenum Oxide as a High-Efficient and Degradable Reactive Oxygen Species Scavenger

Considerable efforts have been made to develop reactive oxygen species (ROS) scavengers for removing high level of ROS. However, most of the reported ROS scavengers are nondegradable and involve harsh reaction conditions as well as utilize various surface ligands. In order to overcome these drawbacks, in the present work, we develop a facile and mild synthesis avenue for preparation of surface-clean hydrogen-doped molybdenum oxide (H_0.34MoO₃) via simply mixing MoO₃ dispersion with aluminum foil under an acidic environment without any surface capping reagents at room temperature. The resulting H_0.34MoO₃ can act as a broad-spectrum ROS scavenger, including ^.OH, H₂O₂, O₂⁻, and ¹O₂ as well as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The free radical scavenging activity of H_0.34MoO₃ achieves as high as 71.6% and 99.1% for ^.OH and DPPH scavenging, which is comparable and superior to that of ascorbic acid that is a classic free radical scavenger. More significantly, the resulting H_0.34MoO₃ is degrade, which can be degraded into molybdate ions under a neutral environment (pH 7.4).

     

长角血蜱卵泡抑素相关蛋白的定性

参照GenBank中长角血蜱致病性Okayama株卵泡抑素基因的核苷酸序列(GenBank Accession No.DQ248886)设计合成一对引物,从本实验室保藏的单克隆洁净长角血蜱饥饿成蜱中快速提取总RNA,通过RT-PCR扩增出814bp的卵泡抑素基因,序列比对结果显示:与长角血蜱致病性Okayama株的核苷酸序列及氨基酸序列一致性分别为97.8%和99%,将其亚克隆到表达载体pGEX-4T-1中进行表达,GST融合重组蛋白预期分子量为57kD。表达重组蛋白经MagneGSTTM蛋白纯化系统纯化后作为抗原分别与抗不同发育阶段长角血蜱(卵、幼蜱、若蜱、成蜱)多克隆抗体作为一抗进行免疫印迹,结果表明:与长角血蜱卵制备的多克隆抗体有很强的免疫反应,而与其他发育阶段(幼蜱、若蜱、成蜱)饥饿长角血蜱制备的多克隆抗体反应性很弱。以上结果表明:长角血蜱卵泡抑素蛋白在长角血蜱产卵及卵成熟发育时期的表达水平较其他发育阶段(幼蜱、若蜱、成蜱)的蛋白表达水平高。     

Purification and Characterization of Cold Adapted Trypsins from Antarctic krill (Euphausia superba)

Three trypsins (TRY-ES) were purified from Antarctic krill (Euphausia superba) by ammonium sulfate precipitation, ion-exchange and gel-filtration chromatography, with relative molecular mass of 28.7, 28.8 and 29.2 kDa respectively. The TRY-ES was inhibited by specific trypsin inhibitors (benzamidine, STI, CHOM and TLCK), with optimum temperature at 40 (Trypsin I), 45 (Trypsin II) and 40 °C (Trypsin III) repetitively. The TRY-ES was stabled between 5 and 40 °C, which was consistent with the red shift in fluorescence intensity peak at 40 °C (Trypsin I) and 45 °C (Trypsin II and Trypsin III) and blue shift at 40 °C (Trypsin II and Trypsin III). The K _cat/K _m values of the TRY-ES was 14.28, 9.46 and 5.93 mM^?1s^?1 respectively, 1.1–10.2 folds higher than trypsins from other crustacean and mammal, which was supported by the differences in thermodynamics parameters, the free energy, enthalpy, and entropy of benzamidine and the TRY-ES system.     

Intervention of Selenium on Chronic Fluorosis-Induced Injury of Blood Antioxidant Capacity in Rats

This study was conducted to further explore the effects of selenium on the blood antioxidant capacity in rats exposed to fluoride to find out the optimal dosage level of selenium. Animals were divided into prevention sequence (Selenium?→?NaF, water?→?NaF) and treatment sequence (NaF?→?Selenium, NaF?→?water) (sodium fluoride 50?mg/L; sodium selenite 0.375, 0.75, 1.5?mg/L). The exposure time was 12?months. Then, the fluidity of erythrocyte membrane by electron spin resonance was analyzed, and the blood was collected for GSH-Px and SOD activity, total antioxidant capacity (T-AOC) and uric acid assay, sialic acid and MDA content. The results showed that, compared with control group, GSH-Px activity and T-AOC level increased significantly (P??0.05). The fluidity of erythrocyte membrane showed significant increase (P?相似文献   

川西林线交错带岷江冷杉幼苗异龄叶形态对长期模拟增温的响应

全球气候变暖对高纬度、高海拔地区的植物形态产生强烈影响。川西林线交错带是青藏高原东部高寒生态系统的重要组成部分,对全球变化极度敏感。以川西林线交错带岷江冷杉(Abies faxoniana)幼苗异龄叶为对象,采用原位开顶式生长室(Open-top chamber,OTCs)模拟增温,研究了长期模拟增温下岷江冷杉幼苗异龄叶片叶长、叶厚等叶形态的响应,采用表型可塑性指数和变异系数对叶形态的可塑性进行分析。结果表明:增温限制岷江冷杉幼苗叶片的增长、增宽和叶面积、体积的扩大,使叶长、叶宽、叶面积、叶体积分别较对照减小12.77%、11.86%、17.76%、11.49%;增温促进叶片厚度的增加,较对照增加7.27%;除叶长宽比外,增温对其余叶形态均产生显著影响(P0.05)。叶形态对模拟增温的响应具有显著的年龄差异(P0.05)。温度、叶龄的交互效应对叶长和叶面积影响显著(P0.05),对叶宽和叶厚影响不显著(P0.05)。两种表型可塑性分析结果表明,除1 a叶叶长外,增温不同程度增大各叶形态可塑性。长期增温使冷杉幼苗叶片有旱生倾向且形态值更发散。研究提供了岷江冷杉幼苗叶片对长期增温的差异性响应证据,为评估青藏高原东缘优势植物对响应气候变暖提供了基础数据和理论参考。     

林窗对岷江冷杉幼苗生存过程的影响

岷江冷杉林是我国西南亚高山暗针叶林的主体之一,其健康的种群动态和更新策略在维持长江上游生态安全方面具有重要意义。为了解岷江冷杉更新过程中林窗对幼苗种群动态的影响,通过调查林窗内和林下岷江冷杉更新幼苗的存活情况,采用数量分析方法研究了幼苗的年龄结构和动态特征。结果表明:林窗内和林下岷江冷杉幼苗的年龄结构金字塔均为两头小中间大的纺锤型,存活曲线均为DeeveyⅡ,生命期望以1龄级的最高、林下种群的高于林窗种群。幼苗的死亡率、消失率、累计死亡率和危险率均随龄级的增加而增大,生存率和死亡密度随龄级的增加而减小;岷江冷杉幼苗种群的数量化动态指数Vpi=0.1059,为增长型种群,在外界随机事件干扰时也可持续增长,尤以林窗种群抵御随机干扰、持续增长的特点更为突出;岷江冷杉幼苗种群的周期波动主要受基波控制,林窗种群在9龄级和11龄级处的波动还受谐波的影响。林窗扩大了岷江冷杉更新幼苗的数量规模、提高了种群抵御外界随机干扰的能力。因此,在岷江冷杉林更新管理中,应高度重视林窗的作用。     

The internal transcribed spacer 1 (ITS-1), a controversial marker for the genetic diversity of Trypanosoma evansi

Seven Trypanosoma evansi isolates from China and a Trypanosoma congolense sp. gifted from Kenya were characterized genetically by the internal transcribed spacer 1 (ITS-1) of nuclear ribosomal DNA (rDNA). The ITS-1 rDNA with the length of 338–342 bp was amplified by polymerase chain reaction (PCR) and sequenced from individual isolates of T. evansi. Although sequence variation between T. evansi isolates from China only was 0.3–3.8%, the constructed phylogenetic tree based on the ITS-1 rDNA sequence by the method of neighbor-joining and maximum parsimony revealed the genetic diversity among T. evansi isolates from China. For T. congolense sp., the most phylogenetically related species was T. congolense IL1180. Although the sequence variation ranged 0.8–14.5% between T. congolense isolates, the phylogenetic tree can not reflected the genetic diversity among T. congolense isolates perhaps because of the fewer number of isolates and sequences. The data could be applicable for the survey of parasite dynamics, epidemiological studies as well as prevention and control of the disease.     

川西亚高山针叶林林窗特征的研究

为探讨川西亚高山针叶林的林窗干扰特征 ,对王朗自然保护区的这一植被类型进行了调查 ,分析了该类型森林中林窗的数量、大小、形状及其成因 ;林窗形成木 (GM )的类型、数量和物种构成。结果表明 ,在川西亚高山原始针叶林林区 ,大多数形成木都是因树木达到一定年龄后衰老等原因引起其抗性下降而死亡的 ;由树木基折形成的林窗最为普遍 ,占 5 1 2 3% ,由干折形成的占 2 0 37% ;单株形成木林窗几乎达到所调查林窗的一半 (占总数的 4 6 99% ) ,平均每个林窗拥有 1 95株形成木。扩展林窗大小多在 10 0～ 4 0 0m2 ,10 0～ 2 0 0m2 所占的数量比例最大 ,占 2 6 5 1% ;而 30 0～ 4 0 0m2 所占的面积比例则最大 ,占 2 2 6 4 %。冠空隙的面积多在 2 0 0m2 以下 ,其中以 5 0～ 10 0m2 所占的数量比例和面积比例均为最大 ,分别为 32 5 3%、17 72 %。冠空隙、扩展林窗的平均面积为 71 6 8m2 、15 4 14m2 。