Role of mitochondrial quality control in exercise-induced health adaptation

Long-term endurance training or physical activity has been confirmed not only to improve physical performance, but to bring about an obvious beneficial effect on human health; however, the mechanism of this effect is not clear. The most studied health adaptations in skeletal muscle response to endurance exercise are increased muscle glycogen level and insulin sensitivity, fiber type transformation toward oxi- dative myofibers, and increased mitochondrial content/function. Mitochondria are dynamic organelles in eukaryotic cells critical in physical performance and disease occurrence. The mitochondrial life cycle spans biogenesis, maintenance, and clearance. Exercise training may promote each of these processes and confer positive impacts on skeletal muscle contractile and metabolic functions. This review focused on the regula- tion of these processes by endurance exercise and discussed its potential benefits in health and disease. We presented evidence suggesting that exercise training potentiates not only the biogenesis of mitochondria but also the removal of old and unhealthy mitochondria through mitochondrial quality control.     

中国地鼠线粒体DNA 16S rRNA基因序列分析及分子系统发育研究

目的通过克隆分析中国地鼠16S基因的部分序列,对中国地鼠16S基因的结构和功能进行初步探索和揭示。方法从GenBank中已报道的啮齿动物16S基因保守区设计一对引物,进行PCR扩增,测序。用Blastn与GenBank中七种啮齿类动物的16S基因进行序列比较,分析其碱基组成及变异情况,并用邻接法(NJ)、非加权组平均法(UPGMA)构建分子系统树,在分子水平上探讨中国地鼠和其他啮齿类动物的进化关系,对中国地鼠的种属地位进行了进一步验证。结果获得了中国地鼠线粒体16S基因的部分序列,其碱基组成A、T、C、G分别为40.5%、24.5%、18.7%、16.3%,与其他七种啮齿类动物的碱基含量相比,各碱基含量基本相似。NJ进化树表明,中国地鼠、金黄地鼠与欧洲仓鼠先聚为一支,小鼠与大鼠先聚为一支,东方田鼠、台湾田鼠与东欧田鼠先聚为一支。结论中国地鼠和金黄地鼠的亲缘关系最近,与传统的分类地位基本吻合。     

Systematics and Species Validity of the Dabieshan Pit Viper Protobothrops dabieshanensis Huang et al. 2012: Evidence from a Mitochondrial Gene Sequence Analysis

Aimed to evaluate the phylogenetic position of the recently described Protobothrops dabieshanensis Huang et al. （2012）, phylogenic relationships of 12 species within Protobothrops based on four mtDNA gene fragments （12S RNA, 16S RNA, ND4 and Cyt b） were reconstructed in our study. The result indicates a clade composed ofP dabiesha- nensis, P. jerdonii and P xiangchengsis with strong support. The genetic distance among P dabieshanensis, P jerdonii and P xiangchengsis was much lower than other congeners. Based on the data from the phylogenetic analysis and pre- viously described morphological differences, we conclude that P dabieshanensis is a valid species with close affinities to P jerdonii and P xiangchengsis.     

Differences in Incubation Length and Hatchling Morphology among Five Species of Oviparous Phrynocephalus Lizards （Agamidae） from China

We incubated eggs of five Phrynocephalus species （P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii） at three constant temperatures （24℃, 28℃ and 32℃） to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size （snout-vent length and body mass） and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.     

一个马铃薯种质资源圃致病疫霉群体的分析

由致病疫霉Phytophthora infestans引起的晚疫病是马铃薯生产上最严重的病害之一,认识其群体结构特征,可为晚疫病防控策略的制定以及抗病品种的合理布局提供指导。对2009年采自宁夏一个种植有93个品种(品系)的马铃薯种质资源圃的致病疫霉进行了交配型、致病型和线粒体DNA单倍型分析,结果表明,116个致病疫霉菌株中存在A1、A2和自育型3种交配型,发生频率分别为24.1%、57.8%和18.1%,A2交配型为优势类型;对其中43个菌株的致病型进行测试,检测到两种致病类型:1.2.3.4.5.6.7.8.9.10.11和3.4.10,发生频率分别为95.3%和4.7%,可克服所有11个抗病基因的1.2.3.4.5.6.7.8.9.10.11类型占绝对优势;对62个菌株的线粒体DNA单倍型进行分析,检测到Ia和IIa两种类型,发生频率分别为74.2%和25.8%。综合表型和基因型数据分析发现,该马铃薯种质资源圃中致病疫霉群体致病型单一,但致病型毒力因子高度复合;线粒体DNA分析表明,该马铃薯种质资源圃引入了遗传背景较为复杂的致病疫霉"新"群体。     

Expression and signal regulation of the alternative oxidase genes under abiotic stresses

Plants in their natural environment frequently face various abiotic stresses, such as drought, high salinity, and chilling. Plant mitochondria contain an alternative oxidase （AOX）, which is encoded by a small family of nuclear genes. AOX genes have been shown to be highly responsive to abiotic stresses. Using transgenic plants with varying levels of AOX expression, it has been confirmed that AOX genes are im- portant for abiotic stress tolerance. Although the roles of AOX under abiotic stresses have been extensively studied and there are several excellent reviews on this topic, the differential expression patterns of the AOX gene family members and the signal regulation of AOX gene（s） under abiotic stresses have not been extensively summarized. Here, we review and discuss the current progress of these two important issues.     

线粒体分裂蛋白抑制剂在大鼠脑缺血再灌注损伤中的作用及其机制

目的:观察线粒体分裂蛋白抑制剂在大鼠脑缺血再灌注损伤中的作用,并初步探讨其在线粒体凋亡途径中的作用机制.方法:雄性Wistar大鼠48只,体重250～300 g,随机分为三组(n=16):假手术组(Sham组)、脑缺血再灌注组(I/R组)和mdivi-1预处理组(mdivi-1组),线栓法建立大鼠大脑中动脉闭塞(MCAO)模型,缺血2小时,再灌注24小时后应用流式细胞术检测神经元凋亡;Western blot法检测Cyt C蛋白的表达;RT-PCR法检测Cyt C mRNA的表达.结果:与Sham组比较,I/R组神经细胞凋亡率与CytC蛋白以及mRNA表达水平显著升高(P＜0.01).应用mdivi-1预处理后细胞凋亡率与CytC蛋白以及mRNA表达水平明显降低(P＜0.01).结论:线粒体分裂蛋白抑制剂可以明显减轻脑缺血再灌注损伤,其作用机制可能通过阻断线粒体-细胞色素C途径来抑制细胞凋亡.     

MiR-210在缺氧中调控机制的研究进展

MicroRNA(miRNA)是一类包含21-25个核苷酸的单链非编码小RNA.研究表明,miR-210可直接抑制线粒体内铁硫蛋白(Fe-S)的支架蛋白ISCUl/2的表达从而抑制线粒体代谢;miR-210对DNA损伤修复基因-RAD家族有抑制作用,减弱了DNA修复能力;miR-210可以通过调节E2F3、纤维母细胞生长因子受体1(FGFRL1)、同源域基因A1(HOXA1)等阻止细胞增殖,调控细胞周期;缺氧刺激可上调miR-210表达,这对促进血管再生有重要作用.miR-210的表达受缺氧诱导,调控缺氧反应相关基因的表达,提示miR-210有可能成为诊治包括缺血性损伤、肿瘤在内等多种疾病的新靶点.     

一种适用于双向电泳分析的高效真菌线粒体提取及蛋白质制样方法

用液氮冷冻研磨法破碎真菌菌丝细胞,通过差速和蔗糖密度梯度离心分离纯化板栗疫病菌线粒体,所得线粒体产率(质量比)约为1/10~4。电子显微镜观察和蛋白印迹表明,所制备的线粒体完整性好,没有检测到其它细胞成分的污染。使用膜蛋白裂解液溶解线粒体制备蛋白样品,将蛋白样品200μg上样于pH3~10,24cm的非线性胶条进行等电聚焦,电聚焦后再进行第二向SDS-PAGE电泳分离,经银染获得重复性好、背景清晰、分辨率高(680±15个蛋白质点)的凝胶图谱。随机选择10个蛋白质点进行质谱分析,9个获得有效注释,均为线粒体特异性蛋白质,表明所制备的蛋白样品非常适合双向电泳分析及其后续的质谱鉴定。     

基于诱导性多潜能干细胞的亨廷顿舞蹈病发病机制研究

目的:基于诱导性多潜能干细胞(induced pluripotent stem cells,i PSC)多潜能性的特点将亨廷顿舞蹈病(Huntington disease,HD)患者和正常人特异性i PSC定向诱导分化成运动神经元,并在运动神经元的基础上探讨HD的发病机制。方法:将HD患者和正常人的i PS细胞在特定的生长因子和神经因子的作用下定向诱导分化成运动神经元。然后用免疫荧光染色检测运动神经元特异性标记物HB9和ISL1的表达。以DCFH-DA和JC-1为荧光探针,利用流式分析法分别对正常人和HD患者运动神经元细胞活性氧和线粒体膜电位进行检测。结果:经过25天诱导分化成功得到HD患者和正常人的运动神经元,并且免疫荧光染色显示,βIII-微管蛋白阳性的神经细胞同时表达运动神经元特异性的标志物HB9和ISL1。此外,经实验统计发现HD患者运动神经元细胞内代表活性氧水平的荧光强度(4704.33±390.50)较正常组(2840.33±166.20)有明显增强(P=0.002),而且代表线粒体膜电位红绿荧光强度比(2.74±0.13)较正常组(3.97±0.29)相比有明显降低(P=0.03)。结论:HD患者特异性i PSC能够诱导分化成运动神经元,为实验提供研究模型。HD的发病与运动神经元细胞线粒体功能障碍有关。