Study on the Complete Mitochondrial Genome of Qaidam Cattle(Bos taurus)

Qaidam cattle(Bos taurus) is an important endemic breed in Northwest China, which is mainly distributed in the northwest of Qinghai-Tibet Plateau. It has strong adaptive ability to plateau and swamp conditions, such as cold tolerance and insect resistance. In this study, the first complete mitochondrial genome of Qaidam cattle was reported. The circular double-stranded genome is 16 340 bp in size, and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop region. The overall nucleotide composition is 33.4% A, 27.2% T, 26.0% C and 13.4% G, with a total A +T content of60.6%. The gene order and composition are similar to those of other B. taurus breeds. Molecular phylogenetic analysis indicated that Qaidam cattle was split as an independent clade and nested within Asian cattle breeds.

Study on Complete Mitochondrial Genome of Oula Sheep(Ovis aries)

Mitochondrial genome has been widely used in species identification and gene conservation.In the present study,the complete mitochondrial genome of Oula sheep(Ovis aries)was determined using next-generation sequencing.This genome was16 618 bp(NCBI accession number:KU575248)and contained 13 protein coding genes,22 transfer RNA genes,two ribosomal RNA genes,and a typical control region.The overall nucleotide composition was 33.7%A,27.4%T,25.8%C,and 13.1%G,with a total A+T content of 61.1%.The phylogenetic analysis of selected sheep breeds showed that Oula sheep were clustered within branch A and originated from approximately 6 ka.This mitochondrial genome will provide valuable information for molecular genetic research of Oula sheep.

Characterization of the Complete Mitochondrial Genome of Przewalski's Gazelle Procapra przewalskii in Bovidae Family of Artiodactyla

The Przewalski's gazelle,Procapra przewalskii,is one of the most endangered species in China,and is now found only in a single small area around the Lake Qinghai.In this study,the complete mitochondrial genome of P.przewalskii was determined and annotated.The circular genome is 16 547-bp long,containing13 protein-coding genes,22 transfer RNA genes,2 ribosomal RNA genes,and a predicted control region.The overall base composition was 34.0% A,24.7% C,28.3% T,and 13.0% G,with a total A + T content of 62.3%.Phylogenetic analysis of all 19 Bovidae species indicated that P.przewalskii showed a close relationship to Procapra gutturosa.Our results provide a great deal of useful information on further studies for conservation biology of Przewalski's gazelle.

fcl基因对须糖多孢菌丁烯基多杀菌素生物合成及生长发育的影响

fcl基因编码的GDP-岩藻糖合成酶(GDP fucose synthetase,GFS),能催化由GDP-D-甘露糖合成GDP-L-岩藻糖过程中的两步差向异构酶和还原酶反应;还参与氨基糖和核糖的生物合成,是调控生物体糖代谢、核苷酸代谢的关键酶之一。通过前期基因组测序表明须糖多孢菌Saccharopolyspora pogona中存在fcl基因。利用基因工程技术构建了fcl基因的过表达菌株S. pogona-fcl和敲除菌株S. pogona-Δfcl。结果表明该基因对菌株生长发育、蛋白表达及其转录水平、杀虫活性、丁烯基多杀菌素的生物合成均存在影响。经HPLC分析显示,S. pogona-Δfcl的丁烯基多杀菌素产量增加为野生型菌株的130%,S.pogona-fcl的丁烯基多杀菌素产量降低了25%。生测结果显示,与野生型菌株相比S.pogona-Δfcl对棉铃虫的杀虫活性明显增强,而S.pogona-fcl的杀虫活性降低。利用扫描电镜观察发现,S. pogona-Δfcl菌丝体表面出现褶皱,呈现短棒状,S. pogona-fcl菌丝形态与野生型菌株一致。以上结果表明,fcl基因的敲除影响菌丝体的生长发育,能促进丁烯基多杀菌素的生物合成和增强杀虫活性,该基因的过表达抑制了丁烯基多杀菌素的生物合成和降低了杀虫活性。SDS-PAGE结果表明,三株菌株在96 h时蛋白表达差异最为明显。对差异蛋白通过实时荧光定量聚合酶链式反应结果显示,三菌株蛋白的转录水平存在显著表达差异。通过研究结果构建了网络代谢调控图,分析fcl基因对须糖多孢菌生长发育及丁烯基多杀菌素生物合成代谢调控网络途径的影响,初步构建了fcl基因调控的代谢途径,为揭示丁烯基多杀菌素生物合成的调控机制及相关后续研究提供了实验依据。