马圆形线虫和马尖尾线虫线粒体全基因组扩增与序列分析

发布时间：2018-06-21 04:37

本文选题：马圆形线虫 + 马尖尾线虫　；参考：《黑龙江八一农垦大学》2015年硕士论文

【摘要】：马圆形线虫（Strongylus equinus）是寄生于马、骡、驴等马属动物结肠和盲肠内的一种线虫，引起贫血、腹泻、水肿等症状。马尖尾线虫(Oxyuris equi)俗称马蛲虫，也寄生于马、驴等马属动物的结肠和盲肠内，引起胃肠道障碍、营养不良、消瘦等症状。感染两种线虫均能导致马属动物生产性能的下降，且广泛流行于世界各地，给畜牧业生产造成严重的经济损失。目前对马圆形线虫和马尖尾线虫的研究仅限于虫体形态学、流行病学、病原诊断及综合防治等方面，而关于两者的线粒体基因组序列分析及进化的研究还未见报道。本研究首先从自然感染的马大肠内采集马圆形线虫和马尖尾线虫虫体，经形态学鉴定后，采用步移PCR方法扩增马圆形线虫和马尖尾线虫线粒体全基因组，同时进行序列分析。结果表明，获得的马圆形线虫和马尖尾线虫线粒体基因组全长分别为14545bp和13641bp，均含有12个蛋白编码基因（protein-coding gene）、2个rRNA基因（rRNA gene）、22个tRNA基因以及分别为3个（马圆形线虫）和1个（马尖尾线虫）非编码区（noncodingregion）。马圆形线虫线粒体全基因组核苷酸组成为：A=31.06%, G=15.72%, C=6.18%,T=47.07%, A+T含量为78.10%。马尖尾线虫线粒体全基因组核苷酸组成为：A=18.89%,G=26.31%, C=5.87%, T=48.93%, A+T含量为67.82%。马圆形线虫的线粒体基因组碱基组成明显偏好碱基T和A，而马尖尾线虫明显偏好碱基T和G，二者的线粒体全基因组中碱基T的含量最高，碱基C的含量最低。马圆形线虫的基因排列顺序属GA3型，马尖尾线虫的基因排列顺序属GA13型。其次，利用线粒体基因组12个蛋白质编码基因的氨基酸序列构建进化系统发生树，探讨马圆形线虫和马尖尾线虫在线虫中的分类地位。以串联的12个蛋白质编码基因氨基酸序列为基因标记，采MP、ML及BI法分别对两种虫体构建系统发生树。马圆形线虫的进化树形成两个大的分支，，寄生于消化系统的线虫为一个分支，寄生于呼吸系统的为另一分支；马圆形线虫位于消化系统的分支上，与普通圆线虫的亲缘关系最近。马尖尾线虫进化树也形成两个大的分支，丝虫目为一个分支，蛔目、圆形目和尖尾目为另一分支，且各目又单独形成一个小的分支，马尖尾线虫位于尖尾目的分支上，与Wellcomia siamensis和蠕形住肠线虫有较近的亲缘关系。通过本研究，首次获得了马圆形线虫和马尖尾线虫的线粒体全基因组序列，进一步丰富了寄生线虫的线粒体基因组库。同时，基于线粒体基因氨基酸序列构建的系统发生树，从分子水平上探讨马圆形线虫和马尖尾线虫在线虫中的分类地位和进化关系。
[Abstract]:Strongylus equinus) is a nematode parasitic in the colon and cecum of horses, mules, donkeys, and so on, causing anemia, diarrhea, edema and other symptoms. Oxyuris equi) commonly known as pinworm, also parasitic in the colonic and cecum of horses, such as horses, donkeys, causing gastrointestinal disorders, malnutrition, wasting and other symptoms. The infection of two nematode species can lead to the decline of the production performance of equine, and it is widespread all over the world, causing serious economic loss to animal husbandry production. At present, the studies on the nematodes and nematodes are limited to the aspects of morphology, epidemiology, pathogen diagnosis and integrated control. However, the studies on their mitochondrial genome sequence analysis and evolution have not been reported. In this study, the circular nematode and the nematode were collected from the naturally infected large intestine of the horse. After morphological identification, the whole mitochondrial genome of the circular nematode and the nematode were amplified by step polymerase chain reaction (PCR), and the sequence analysis was carried out at the same time. The results show that The full-length mitochondrial genomes of nematode rotunda and nematode equina were 14545bp and 13641 BP, respectively, containing 12 protein coding genes, two rRNA genes, 22 tRNA genes, and three rRNA genes and one rRNA gene, respectively. The noncoding region of Nematomyces cuspidata is noncoding region. The nucleotide composition of the whole mitochondrial genome of nematode rotunda was: 1: An31.06.The content of T was 78.10, and the content of T was 78.10. The nucleotide composition of the whole mitochondrial genome of nematode equina was: 1: A0 18.89 and GN 26.31. The content of T was 67.82, and the content of T was 48.93, and the content of T was 67.82. The base composition of mitochondrial genome of nematode equina was obviously preferred to base T and A, while the content of base T and G in the whole mitochondrial genome was the highest, and the content of base C was the lowest in the whole mitochondrial genome. The gene sequence of rotund nematode belongs to GA3 type, and the gene sequence of P. equina belongs to GA13 type. Secondly, phylogenetic tree was constructed by using amino acid sequences of 12 protein coding genes in mitochondrial genome, and the taxonomic status of rotund nematode and online nematode was discussed. The phylogenetic tree of 12 protein coding genes were constructed by MPN ML and BI method respectively using the amino acid sequences of 12 protein coding genes as gene markers. The evolutionary tree of the orbicular nematode forms two large branches, one branch of the nematode parasitic to the digestive system and the other branch of the respiratory system; the nematode is located on the branch of the digestive system. It has the closest relationship with the common nematode. The phylogenetic tree also forms two large branches, one branch of filariformes, another branch of orbicular and acuminata, and a small branch of each order, and the nematode is located on the branch of the order Acanthoptera. It has close relationship with Wellcomia siamensis and peristaltic nematode. In this study, the whole mitochondrial genome sequences were obtained for the first time, which further enriched the mitochondrial genome library of parasitic nematodes. At the same time, the phylogenetic tree was constructed based on the amino acid sequence of mitochondrial gene. The taxonomic position and evolutionary relationship of rotund nematode and online nematode were discussed from the molecular level.
【学位授予单位】：黑龙江八一农垦大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S852.7

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