Oxidative stress tolerance in the filamentous green algae Cladophora glomerata and Enteromorpha ahlneriana

Cladophora glomerata (L.) Kütz. and Enteromorpha ahlneriana Bliding are morphologically similar filamentous green algae that are dominants in the upper littoral zone of the brackish Baltic Sea. As these two species co-exist in a continuously fluctuating environment, we hypothesised that they may have different strategies to cope with oxidative stress. This was tested in laboratory experiments through stressing the algae by high irradiance (600 μmol photons PAR m⁻² s⁻¹) at two different temperatures (15 and 26 °C) in a closed system. Thus, oxidative stress was created by high irradiance (photo-oxidative stress) and/or carbon depletion. The extent of lipid oxidative damage, antioxidant enzyme activities and the amount of hydrogen peroxide excreted by the algae to the surrounding seawater medium were measured. The results suggest that the two species have different strategies: the annual C. glomerata could be classified as a more stress-tolerant species and the ephemeral E. ahlneriana as a more stress-susceptible species. Low temperature in combination with high irradiance created less lipid oxidative damage in C. glomerata than in E. ahlneriana, which was probably related to the higher regular activities of the hydrogen peroxide scavenging enzymes catalase and ascorbate peroxidase in C. glomerata, whereas in E. ahlneriana high activities of these enzymes were only obtained after the induction of oxidative stress. Superoxide dismutase activities were similar in both species, but the mechanisms to remove the hydrogen peroxide produced by the action of this enzyme were different: more through scavenging enzymes in C. glomerata and more through excretion to the seawater medium in E. ahlneriana. The high excretion of hydrogen peroxide, possibly in combination with brominated volatile halocarbons, by E. ahlneriana may have a negative effect on epiphytes and may partly explain why this alga is usually remarkably devoid of epiphytes and grazers compared to C. glomerata.     

四川省老河沟自然保护区兽类多样性红外相机调查

自然保护区的生物物种编目是区域性和全国性生物多样性研究与监测的基础,而红外相机调查技术已成为兽类物种编目的重要手段之一。老河沟自然保护区位于四川省岷山北部,位于大熊猫岷山种群分布核心地区,是2012年新建保护区。从2011-2014年,我们把保护区划分为1km×1km的方格,采用红外相机技术,对区内的兽类多样性进行了系统全面的调查。经过9,188个相机日的调查,共记录到分属7目18科的兽类。其中,有81,709份记录可以鉴定出具体物种,包括野生兽类24种,家畜1种（家狗）,分属5目14科,独立探测数总计1,766次。其余未能鉴定出具体物种的兽类记录为小型翼手目、食虫目和啮齿目动物。在24种野生兽类中,食肉目物种数最多,共4科9种;其次为偶蹄目（4科7种）与啮齿目（3科6种）。就独立探测数而言,偶蹄目兽类是记录到次数最多的类群（占总探测数43.97%）,其次是啮齿目（25.61%）和食肉目（22.44%）。被IUCN红色名录评估为“濒危EN”、“易危VU”和“近危NT”级别的物种各3种,被列为国家I级和II级重点保护野生动物的分别为4种和5种。本次调查对老河沟自然保护区内的大中型兽类进行了首次系统性编目,了解了区内兽类群落的物种组成、空间分布与相对多度,为后续的科研项目和保护管理提供了本底数据和基础信息。     

不同森林管理预案对松鼠生境的影响

应用空间直观的森林景观干扰演替模型（LANDIS）模拟了2000—2200年间小兴安岭友好林区4种森林管理预案（无采伐、皆伐、择伐Ⅰ和择伐Ⅱ）下的森林景观变化,并结合景观尺度的生境适宜度指数（HSI）模型评估了不同管理预案对研究区松鼠生境的影响.结果表明：研究期间,无采伐下松鼠适宜生境面积的增幅最快,而勉强适宜生境的降幅最快;皆伐下,松鼠适宜生境面积的增幅最慢,而勉强适宜生境的后期降幅最小;择伐Ⅰ下松鼠适宜生境面积的增幅高于择伐Ⅱ,而其勉强适宜生境面积的降幅低于择伐Ⅱ.整体而言,松鼠生境最优化的管理方案依次为无采伐、择伐Ⅰ、择伐Ⅱ和皆伐.     

人的重组促黄体生成素对小鼠卵母细胞体外受精的影响

目的探讨人的重组促黄体生成素(r-hLH)对性成熟前的小鼠卵母细胞体外受精(invitrofertilization,IVF)后的分裂、以及IVF胚的体外培养(invitroculture,IVC)过程中发育状况的影响.方法选用性成熟前的清洁级昆明小鼠,分别用r-hFSH(人的重组促卵泡素20IU),r-hFSH+r-hLH(各20IU)或20IUr-hLH对其进行超排处理,通过对从各处理组小鼠卵巢中手工器械分离出来的卵丘-卵母细胞复合体(cumulusenclosedoocyte,CEO)进行体外受精之后,进一步观察这些CEO经IVF后的受精分裂状况,以及IVC后的发育情况.结果r-hFSH+r-hLH处理组小鼠卵母细胞IVF率(72.2%)极显著高于r-hFSH单独处理组(39.9%)或r-hLH单独处理组(37.2%)的相应指标;r-hFSH+r-hLH处理组和r-hFSH单独处理组的IVF胚,发育至8～16细胞阶段的比例(8～16细胞率)趋于一致(25.15%∶27.18%),但是都极显著高于r-hLH处理组的8～16细胞率(17.24%);r-hFSH处理组IVF胚发育至16～32细胞阶段的总比例(16～32细胞率∶33.01%),极显著高于r-hFSH+r-hLH处理组及r-hLH单独处理组的指标(1.75%和0).结论在IVF条件下,r-hLH对小鼠卵母细胞的受精有明显的促进作用,同时却对相应IVF胚的进一步发育产生明显的抑制作用.     

Molecular modeling and dynamics studies of Shikimate Kinase from Bacillus anthracis

Bacillus anthracis has been used as weapon in bioterrorist activities, with high mortality, despite anti-microbial treatment, which strongly indicates a need of new drugs to treat anthrax. Shikimate Pathway is a seven-step biosynthetic route which generates chorismic acid. The shikimate pathway is essential for many pathological organisms, whereas it is absent in mammals. Therefore, these enzymes are potential targets for the development of non-toxic anti-microbial agents and herbicides and have been submitted to intensive structural studies. Shikimate Kinase is the fifth enzyme of shikimate pathway and catalyzes the specific phosphorylation of the 3-hydroxyl group of shikimate using ATP as a co-substrate, resulting in shikimate-3-phosphate and ADP. The present work describes for the first time a structural model for the Shikimate Kinase from B. anthracis using molecular modeling approach and molecular dynamics simulations. This study was able to identify the main residues of the ATP-binding and the shikimate pockets responsible for ligand affinities. Analysis of the molecular dynamics simulations indicates the structural features responsible for the stability of the structure. This study may help in the identification of new inhibitors for this enzyme.     

间歇性低压低氧与连续性低压低氧对大鼠血液动力学作用的比较(英文)

本研究旨在探讨并比较慢性间歇性低压低氧（intermitten thypobaric hypoxia,IHH）和慢性连续性低压低氧（continuous hypobaric hypoxia,CHH）对大鼠血液动力学作用的影响。40只成年Sprague—Dawley大鼠随机分为5组：对照组（CON）,28天IHH处理组（IHH28）,42天IHH处理组（IHH42）,28天CHH组（CHH28）和42天CHH组（CHH42）。IHH火鼠于低压氧舱分别接受28或42天模拟5000m海拔高度低氧（11．1％O2）处理、每天6h。CHH处理大鼠生活在低压氧舱环境中,除每天半小时常氧供食、供水和清洁外,其余时间均分别接受时程为28或42天的模拟5000m海拔高度低氧（11．1％O2）处理。每周定时测定大鼠体重。通过导管法测定基础常氧和急性低氧状态下的血液动力学,包括半均动脉压（meanartery blood pressure,MAP）、心率（heartrate,HR）、左审收缩峰压（1eft ventricular systolic pressure,LVSP）、正负左率最人压力变化速率（maximum change rate of left ventricular pressure,±LVdP／dtmax）。通过生物化学方法测定大鼠心肌超氧化物岐化酶活性和丙二醛含量。并分别测定全心、左心室和右心室重量。结果显示：（1）CHH42大鼠基础HR和MAP低于CON,IHH和CHH28大鼠（P〈0．05）。（2）IHH大鼠表现出明显的抗心肌缺氧／复氧损伤作用,表现为急性低氧状态下的HR、MAP、LVSP和＋LVdP/dtmax,改变明显低于CON大鼠（P〈0．05）;CHH大鼠表现出更为明显的抗急性低氧心脏保护作用,表现为急性低氧的HR、MAP、LVSP和±LVdP/dtmax;改变明显低于CON和IHH火鼠（P〈0．05）,但出现复氧损伤作用,表现为复氧过程中血液动力学的恢复明显低于CON和IHH大鼠（P〈0．05）。（3）与CON大鼠相比较,IHH和CHH大鼠心肌抗氧化能力明显增强（P〈0．05,P〈0．01）。（4）与IHH和CON大鼠相比较,CHH大鼠表现明显的右心室肥厚（P〈0．01）。结果表明,IHH可诱导有效的心脏保护作用,而无明显的不良反应,因而具有潜在的实际应用价值。     

Orthopoxvirus Detection in Environmental Specimens during Suspected Bioterror Attacks: Inhibitory Influences of Common Household Products

After terrorists attacked the United States in 2001, the appearance of letters and other objects containing powdery substances with unknown potentials for biological threat focused attention on the speed, sensitivity, and reliability of diagnostic methods. This study summarizes the abilities and limitations of real-time PCR, electron microscopy (EM), and virus isolation when used to detect potential bioweapons. In particular, we investigated the inhibitory influences of different common household products present in environmental specimens on PCR yield, EM detection, and virus isolation. We used vaccinia virus as a model for orthopoxviruses by spiking it into specimens. In the second part of the study, we describe modifications of diagnostic methods to overcome inhibitory effects. A variety of PCR amplification enhancers, DNA extraction protocols, and applications of internal controls were evaluated to improve diagnostic simplicity, speed, and reliability. As a result, we strongly recommend using at least two different frontline techniques in parallel, e.g., EM and PCR. A positive result obtained by any one of these techniques should be followed by a biological method to confirm the putative diagnosis. Confirmatory methods include virus isolation followed by an agent-specific immunofluorescence assay to confirm the presence of replication-competent particles.     

牲畜粪便与麦秆混合厌氧发酵的产气量、发酵时间及最优温度

探索牲畜粪便与作物秸秆混合发酵的产气量和发酵时间与发酵温度之间的关系,是解决农村户用沼气原料选择、确定最优发酵温度和提高农作物秸秆资源化利用效率的关键.采用可控型恒温发酵装置,以猪粪、牛粪和麦秆作为发酵原料,以常温厌氧发酵池的底物为接种物,在总固体（total solid,TS）质量分数为8%的条件下进行批量试验,研究了混合发酵的产气量、发酵时间及最优温度.结果表明：粪便与麦秆混合发酵明显提高了原料的产气效率,其中猪粪与麦秆混合发酵的累积产气量比猪粪作为单一发酵原料高24倍,而牛粪与麦杆混合发酵的累积产气量与单一牛粪无显著差异.猪粪、牛粪与麦秆混合发酵的最优温度均在30 ℃以上,发酵时间在60 d左右.厌氧发酵的发酵时间不总是随着温度的升高而缩短,单一以温度来断定厌氧发酵时间的长短是不可行的.     

人hIL-24Δ103重组腺病毒感染诱导A549细胞凋亡

白细胞介素24（interleukin 24,IL-24）是近年来新发现的1个IL-10家族细胞因子,具有明显的抗肿瘤活性．为了研究开发高活性、低分子量的IL-24,并探讨其用于肿瘤靶向治疗的可能性,本研究在前期基础上,进一步构建并制备了缺失N端103个氨基酸残基的IL-24（hIL-24Δ103）重组腺病毒,并观察了其对A549细胞生长增殖和凋亡的影响．首先,采用PCR技术扩增IL-24第104位至第206位氨基酸区域的编码序列,制备hIL-24Δ103重组腺病毒．用Ad-hIL-24Δ103重组腺病毒感染肺癌A549细胞. MTT分析结果表明,Ad-hIL-24Δ103感染显著抑制了A549细胞的生长．Hoechst 33258染色和流式细胞仪分析结果表明,Ad-hIL 24Δ103感染导致细胞凋亡．Western 印迹分析结果表明,Ad-hIL-24Δ103感染导致了PKR和eIF-2α蛋白的表达上调与磷酸化激活,提示PKR和eIF-2α参与了hIL-24Δ103导致的细胞生长抑制和细胞凋亡过程的调节．关键词 人白介素24;腺病毒;细胞增殖;细胞凋亡     

针对SARS冠状病毒重要蛋白的siRNA设计(英)

RNA干涉(RNA interference, RNAi)是一种特异性地导致转录后基因沉默的现象,在哺乳动物细胞中小分子干扰RNA双链体(small interfering RNA duplexes, siRNA duplexes)可以有效地诱导RNAi现象,为一些疾病的治疗开辟了新的途径.针对SARS冠状病毒(SARS coronavirus, SARS-CoV)中编码5个主要蛋白质的基因,用生物信息学的方法设计了348条候选siRNA靶标.在理论上,相应的siRNA双链体能特异地抑制SARS-CoV靶基因的表达,同时不会影响人体细胞基因的正常表达,这为进一步siRNA类药物的实验研究提供了理论基础.