High genetic diversity of Tibetan Mastiffs revealed by mtDNA sequences

Many studies have been reported the origin and evolution of domesticated animals, particularly dogs, however, few have system-atically examined the Tibetan Mastiff (TM), a dog that lives primarily in the Qing-Tibet Plateau. Here, we study the origin and evolution of TM based on the population comparison of mtDNA D-loop sequences from TM and other dogs across the world. Intriguingly, non-simultaneous arrivals of Tibetan Mastiffs ancestors to Tibet occurred, which may result from continuous Tibetans’ settlement on Qing-Tibet Plateau supported by archaeological and genetic evidence. High genetic and haplotype diversity and robust haplotypes sharing with other dogs unique to East Asia are observed in Tibetan Mastiff, supporting that it is a very archaic breed derived probably from East Asia.     

游泳训练联合补充α-硫辛酸对WistarⅡ型糖尿病大鼠心肌线粒体的保护作用

将60只wistar大鼠糖尿病造模完成后随机分成4组,即对照组(CON)、α-硫辛酸(LA)组、游泳训练组(SEX)和α-硫辛酸+游泳训练组(SEX+ LA)进行训练,训练结束后,检测大鼠心肌线粒体呼吸功能、氧化磷酸化蛋白表达及氧化应激相关指标,以便对游泳训练及联合补充α-硫辛酸对Ⅱ型糖尿病大鼠心肌线粒体的保护作用的内在影响机制进行探索.结果显示:α-硫辛酸和游泳运动均可以显著性改善糖尿病引起的3态呼吸水平、呼吸控制率及磷氧比值降低(P ＜0.05);联合作用在提高3态呼吸及降低4态呼吸方面存在增强作用(P＜0.05).在对氧化磷酸化蛋白表达的影响方面,α-硫辛酸可有效提高complex Ⅰ、Ⅲ蛋白表达;游泳训练具有和α-硫辛酸相似的作用效果,且能显著性地上调complex Ⅳ表达水平(P＜0.05),联合作用在提高complexⅠ、Ⅲ蛋白表达水平上存在加强作用(P ＜0.05).在降低组织氧化应激水平方面,各种干预方式均可降低ROS含量,提高抗氧化蛋白SOD和GSH-Px水平(P＜0.05);联合作用方式在降低ROS,增强SOD水平上有叠加作用(P＜0.05).以上结果说明,游泳训练及联合补充α-硫辛酸可能通过对抗氧化酶活性的提高,进一步降低ROS对呼吸链复合物及膜结构的损伤而实现线粒体呼吸功能的增强.     

细胞应激条件下嗜热四膜虫线粒体膜电位变化研究

单细胞线虫纲原生动物四膜虫(Tetrahymena),在H2O2的诱导下可发生凋亡样死亡.另外,最新研究表明细胞中活性氧簇(ROS)的积累可有效地诱导细胞自噬途径的发生.通过流式细胞技术和荧光显微技术,检测了经饥饿和ROS诱导剂处理后,线粒体内膜电位变化及细胞内ROS的积累.此外,应用两种抗氧化剂氮乙酰半胱氨酸(NAC)和过氧化氢酶(Catalase)分别对四膜虫细胞进行处理,检测了在氧化应激条件下的抗氧化作用效果.结果表明,Oligomycin和Menadione可有效抑制线粒体膜电位的维持,从而导致细胞内ROS积累.同时,H2O2处理和饥饿处理可以导致嗜热四膜虫细胞线粒体膜电位丧失以及细胞质ROS积累.另外,N-acetylcystine和Catalase可有效地降低四膜虫细胞内ROS的积累,以及保持四膜虫细胞线粒体内膜电位,维持通透性.     

猛禽和夜鹰类的线粒体DNA序列比较和分子进化关系的研究

测定和比对了隼形目、鸮形目、夜鹰目的12SrRNA基因片段，长度为415bp．使用MEGA2．1软件构建分子系统树并分析其系统进化关系．数据显示，该基因片段的DNA序列变异丰富，转换和颠换数未随着遗传距离的增加而出现饱和现象，反映出较高真实水平的鸟类系统发育关系．重建系统进化树表明：与隼形目隼科相比，隼形目鹰科与鸮形目、夜鹰目的亲缘关系更近，提示了隼形目隼科和鹰科之间可能存在着较大的遗传变异；与夜鹰目相比，鸮形目和隼形目鹰科鸟类的亲缘关系较近，与传统分类观点相同，不支持将鸮形目和夜鹰目合并为鸮形目的观点．     

Species-specific aminoacylation of Oryza sativa mitochondrial tRNA^Trp

Accuracy in protein synthesis is essential to the survival of all organisms. Aminoacyl-tRNA synthetases catalyzed aminoacylation is the basis of the fidelity of protein synthesis[1]. In recent years, the identification of nucleotide determinants, specific…     

施氏屋顶鼠和海南屋顶鼠的线粒体12S rRNA基因序列的歧异及其系统进化关系

屋顶鼠的两个亚种--施氏屋顶鼠和海南屋顶鼠的外形和毛色相似,在一些标本的测量记录中,它们间的主要区别特征之一的尾长与体长比却是不肯定的.在广东,海南屋顶鼠仅分布于粤西区,而施氏屋顶鼠则分布于其余区域.在我们的这项研究中,采用了9个分别来自于施氏屋顶鼠(龙门种群和香港种群)及海南屋顶鼠的样品进行了线粒体12S rRNA 基因的测序,在所分析的 385个核苷酸位点长度的片段中,包含有26个变异位点和14个简约信息点,观察到3个插入/缺失位点.通过邻接法和最大简约法重建这些鼠类样品的系统进化关系.相比于施氏屋顶鼠的香港种群,海南屋顶鼠与施氏屋顶鼠的龙门种群有着更紧密的亲缘关系.基于12S rRNA 基因片段的序列数据,本项分析不赞同把海南屋顶鼠分类成为一个亚种的观点,认为海南屋顶鼠的形态变化是自然选择的结果,并由此导致当地适应和地理隔离.     

Phylogenetic relationships of host insects of Cordyceps sinensis inferred from mitochondrial Cytochrome b sequences

This study used the sequence of the mitochondrial Cytochrome b (Cytb) to estimate phylogenetic relationships among host Hepialidae insects of Cordyceps sinensis. Genome DNA of host insect was extracted from the dead larva head part of 18 cordyceps populations and 2 species of Hepialus, and the Cytb fragment of host insect was amplified with PCR technique. The nucleotide sequence alignments and their homologous sequences of 24 species host Hepialidae insects of Cordyceps sinensis were obtained from GenBank and were used to construct phylogenetic trees based on neighbor-joining method. The results showed that genus Bipectilus diverged earlier than genus Hepialus and Hepialiscus. Hepialus host insects of Cordyceps sinensis have multitudinous species with different morphological characteristics and geographical distributions. The interspecific genetic differentiations are obvious in Hepialus. Thus, the genus Hepialus might be considered as polyphyletic origin. Cytb sequences have abundant variations among the host insects of Cordyceps sinensis on specific and generic level. The divergence rate of Cytb sequences among the species in Hepialus ranged from 0.23% to 9.24%, except that Hepialus pratensis and Hepialus jinshaensis have the same sequence. Cytb sequence can be used for species identification of host insects of Cordyceps sinensis, but further confirmation in more host insect species is needed. To obtain the Cytb sequence of host insect by amplifying DNA extracted from the head part of dead larva in cordyceps turns out to be an effective and accurate approach, which will be useful for studies on phylogeny and genetic structure of host insects of cordyceps populations, especially for analyzing relationships between C. sinensis and its host insects.     

Mitochondrial DNA analysis of ancient Sampula population in Xinjiang

The archaeological site of Sampula cemetery was located about 14 km to the southwest of the Luo County in Xinjiang Khotan, China, belonging to the ancient Yutian kingdom. ¹⁴C analysis showed that this cemetery was used from 217 B.C. to 283 A.D. Ancient DNA was analyzed by 364 bp of the mitochondrial DNA hypervariable region I (mtDNA HVR-I), and by six restriction fragment length polymorphism (RFLP) sites of mtDNA coding region. We successfully extracted and sequenced intact stretches of maternally inherited mtDNA from 13 out of 16 ancient Sampula samples. The analysis of mtDNA haplogroup distribution showed that the ancient Sampula was a complex population with both European and Asian characteristics. Median joining network of U3 sub-haplogroup and multi-dimensional scaling analysis all showed that the ancient Sampula had maternal relationship with Ossetian and Iranian.     

Seasonal changes in the critical arousal temperature of the marsupialSminthopsis crassicaudata correlate with the thermal transition in mitochondrial respiration

Summary During periods of torporSminthopsis crassicaudata, a dasyurid marsupial, regulated its body temperature above about 16.3°C in summer and 13.0°C in winter. Animals with lower body temperatures were unable to arouse. Liver, heart and brain mitohondrial succinate:cytochrome c reductase showed a thermal transition at 16°C in summer and at 12.5°C in winter. Thus the lowest regulated body temperature was just above the temperature where changes were detected in mitochondrial respiration.Acknowledgments. This work was supported by a Flinders University Research Scholarship Award to F. Geiser. We thank Prof. J. H. Bennett for the supply of animals and M. O'Driscoll for the animal maintenance.