扁形动物降解组的比较分析和寄生适应性研究
发布时间：2019-01-30 10:06
【摘要】：一个生物体内所有的蛋白水解酶(protease)(简称蛋白酶)的总和称为降解组(degradome)。蛋白酶能够水解蛋白质底物中的肽键,从而参与种种重要的生命活动功能。扁形动物包括三个大的类别的生物,分别是营自由生活的涡虫,寄生生活的吸虫与绦虫,吸虫与绦虫虽然都是寄生生活,但寄生环境与营养取食方式迥然不同。扁形动物的这些不同可能会导致它们的降解组产生与之相适应的不同生物学特点,为寄生适应性的研究提供了一个理想的模型。本文选择了七种扁形动物作为研究对象,构建了它们的降解组,进行了降解组之间的比较基因组学分析,调查蛋白酶在不同类型的扁形动物中的多样性及各自的特点,并对寄生扁形动物在降解组方面的寄生适应性做了一些探讨。获得如下主要结果和结论:首先通过对几种扁形动物的基因组的同源搜索寻找基因组中的蛋白酶,构建了七个扁形动物的降解组。对三类扁形动物两两之间特有的蛋白酶进行种类和功能上的比对,发现涡虫相比于吸虫和绦虫具有更多特有的蛋白酶,并且这些蛋白酶的功能更宽泛,参与的生物过程也更多样;吸虫与绦虫各自所特有的蛋白酶相对涡虫较少,所执行的功能基本和涡虫相应功能一致。相对于吸虫和绦虫,涡虫独特的蛋白酶的功能体现在诸如运动,与神经系统发生相关的生物粘附等方面。这些差别与涡虫和两类寄生虫之间的生理特点和生活环境的差异相一致:涡虫营自由生活,运动机能和神经系统等方面更加发达,而吸虫和绦虫因为.寄生,这些机能相对退化,因此涡虫的蛋白酶系统比吸虫和绦虫更加发达。两类同是寄生虫的吸虫和绦虫之间的比较结果表明:它们各自特有的蛋白酶在功能上也有所不同,但都是参与基本的生命活动相关的蛋白酶。同属于吸虫的血吸虫与华支睾吸虫相比,蛋白酶数目和种类都很相似,这与它们较近的亲缘关系及相似的生活方式是一致的。对吸虫类降解组的进一步比较分析发现,血吸虫蛋白酶发生了 一系列与该生物特定的寄生生活相关的适应性进化,主要体现在与消化和入侵两个相关方面。吸虫为了高效消化血红蛋白,参与消化的组织蛋白酶B、D发展出新的酶亚型,而且有的酶分子亚型有复制现象,产生了了多个拷贝,选择压力分析发现组织蛋白酶D明显受到正选择作用。华支睾吸虫参与消化的天冬氨酸蛋白酶A01家族有扩增现象。入侵宿主方面,血吸虫产生了几个新酶:S01家族中的弹性蛋白酶和尾蚴蛋白酶,M08家族中的入侵蛋白酶。而绦虫降解组中以丢失一些酶为主,基因组间的比较发现绦虫发生了相关酶的基因甚至整个代谢途径的丢失。在氨基酸和核酸代谢方面,绦虫和吸虫一样均丢失了一些相似的蛋白酶。
[Abstract]:The sum of all the proteolytic enzymes (protease) (in an organism is called the degradation group (degradome). Proteases can hydrolyze peptide bonds in protein substrates, thus participating in important biological activities. Flattened animals include three large groups of organisms, which are trematodes, trematodes and tapeworms, and trematodes and tapeworms, both of which are parasitic, but the parasitic environment and feeding patterns are very different. These differences in flattened animals may lead to different biological characteristics of their biodegradable groups, which provide an ideal model for the study of parasitic adaptation. In this paper, seven kinds of flattened animals were selected as research objects, their degradation groups were constructed, comparative genomics analysis was carried out among the degradation groups, and the diversity and characteristics of protease in different types of flattened animals were investigated. The parasitic adaptability of parasitic flattened animals in degradation group was also discussed. The main results and conclusions are as follows: firstly, seven degradation groups of flattened animals were constructed by homologous searching for the protease in the genome of several flattened animals. By comparing the types and functions of the proteases peculiar to each other in three groups of flat animals, we found that the trematode has more specific proteases than the trematodes and tapeworms, and that these proteases have more extensive functions. The biological processes involved are also more diverse; The specific proteases of paragonimiasis and tapeworm were less than that of trematode, and the function of trematode was basically the same as that of trematode. Compared with paragonimiasis and tapeworm, the unique protease function of the trematode is embodied in such aspects as movement, biological adhesion related to nervous system, and so on. These differences are consistent with the differences in physiological characteristics and living environment between the two parasites: free living, motor function and nervous system, while trematode and tapeworm are more developed. Parasitism, these functions are relatively degraded, so the protease system of the paragonimus is more developed than the trematode and tapeworm. The comparison between the two parasites, trematode and tapeworm, showed that their specific proteases were different in function, but they were all proteases involved in basic life activities. Compared with Schistosoma sinensis and Clonorchis sinensis, the number and species of protease are similar, which is consistent with their close relationship and similar lifestyle. Further comparative analysis of trematode degradation group showed that Schistosoma japonicum protease had a series of adaptive evolution related to the specific parasitic life of the organism, mainly in the aspects of digestion and invasion. In order to digest hemoglobin efficiently, a new enzyme subtype, cathepsin Bad, was developed, and some enzyme molecular subtypes were duplicated, resulting in multiple copies. Selection pressure analysis showed that cathepsin D was significantly affected by positive selection. The aspartate proteinase A 01 family involved in digestion by Clonorchis sinensis was amplified. In invading host, Schistosoma japonicum produced several new enzymes: elastase and cercariin in S01 family and invasive protease in M08 family. In the degradation group of tapeworm, some enzymes were mainly lost, and the genome comparison showed that the genes of the related enzymes and even the whole metabolic pathway were lost in Taenia solium. In amino acid and nucleic acid metabolism, tapeworm and trematode have lost some similar protease.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q95
本文编号：2418020
[Abstract]:The sum of all the proteolytic enzymes (protease) (in an organism is called the degradation group (degradome). Proteases can hydrolyze peptide bonds in protein substrates, thus participating in important biological activities. Flattened animals include three large groups of organisms, which are trematodes, trematodes and tapeworms, and trematodes and tapeworms, both of which are parasitic, but the parasitic environment and feeding patterns are very different. These differences in flattened animals may lead to different biological characteristics of their biodegradable groups, which provide an ideal model for the study of parasitic adaptation. In this paper, seven kinds of flattened animals were selected as research objects, their degradation groups were constructed, comparative genomics analysis was carried out among the degradation groups, and the diversity and characteristics of protease in different types of flattened animals were investigated. The parasitic adaptability of parasitic flattened animals in degradation group was also discussed. The main results and conclusions are as follows: firstly, seven degradation groups of flattened animals were constructed by homologous searching for the protease in the genome of several flattened animals. By comparing the types and functions of the proteases peculiar to each other in three groups of flat animals, we found that the trematode has more specific proteases than the trematodes and tapeworms, and that these proteases have more extensive functions. The biological processes involved are also more diverse; The specific proteases of paragonimiasis and tapeworm were less than that of trematode, and the function of trematode was basically the same as that of trematode. Compared with paragonimiasis and tapeworm, the unique protease function of the trematode is embodied in such aspects as movement, biological adhesion related to nervous system, and so on. These differences are consistent with the differences in physiological characteristics and living environment between the two parasites: free living, motor function and nervous system, while trematode and tapeworm are more developed. Parasitism, these functions are relatively degraded, so the protease system of the paragonimus is more developed than the trematode and tapeworm. The comparison between the two parasites, trematode and tapeworm, showed that their specific proteases were different in function, but they were all proteases involved in basic life activities. Compared with Schistosoma sinensis and Clonorchis sinensis, the number and species of protease are similar, which is consistent with their close relationship and similar lifestyle. Further comparative analysis of trematode degradation group showed that Schistosoma japonicum protease had a series of adaptive evolution related to the specific parasitic life of the organism, mainly in the aspects of digestion and invasion. In order to digest hemoglobin efficiently, a new enzyme subtype, cathepsin Bad, was developed, and some enzyme molecular subtypes were duplicated, resulting in multiple copies. Selection pressure analysis showed that cathepsin D was significantly affected by positive selection. The aspartate proteinase A 01 family involved in digestion by Clonorchis sinensis was amplified. In invading host, Schistosoma japonicum produced several new enzymes: elastase and cercariin in S01 family and invasive protease in M08 family. In the degradation group of tapeworm, some enzymes were mainly lost, and the genome comparison showed that the genes of the related enzymes and even the whole metabolic pathway were lost in Taenia solium. In amino acid and nucleic acid metabolism, tapeworm and trematode have lost some similar protease.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q95
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