扁形動物降解組的比較分析和寄生適應(yīng)性研究
發(fā)布時間：2019-01-30 10:06
【摘要】：一個生物體內(nèi)所有的蛋白水解酶(protease)(簡稱蛋白酶)的總和稱為降解組(degradome)。蛋白酶能夠水解蛋白質(zhì)底物中的肽鍵,從而參與種種重要的生命活動功能。扁形動物包括三個大的類別的生物,分別是營自由生活的渦蟲,寄生生活的吸蟲與絳蟲,吸蟲與絳蟲雖然都是寄生生活,但寄生環(huán)境與營養(yǎng)取食方式迥然不同。扁形動物的這些不同可能會導(dǎo)致它們的降解組產(chǎn)生與之相適應(yīng)的不同生物學(xué)特點,為寄生適應(yīng)性的研究提供了一個理想的模型。本文選擇了七種扁形動物作為研究對象,構(gòu)建了它們的降解組,進(jìn)行了降解組之間的比較基因組學(xué)分析,調(diào)查蛋白酶在不同類型的扁形動物中的多樣性及各自的特點,并對寄生扁形動物在降解組方面的寄生適應(yīng)性做了一些探討。獲得如下主要結(jié)果和結(jié)論:首先通過對幾種扁形動物的基因組的同源搜索尋找基因組中的蛋白酶,構(gòu)建了七個扁形動物的降解組。對三類扁形動物兩兩之間特有的蛋白酶進(jìn)行種類和功能上的比對,發(fā)現(xiàn)渦蟲相比于吸蟲和絳蟲具有更多特有的蛋白酶,并且這些蛋白酶的功能更寬泛,參與的生物過程也更多樣;吸蟲與絳蟲各自所特有的蛋白酶相對渦蟲較少,所執(zhí)行的功能基本和渦蟲相應(yīng)功能一致。相對于吸蟲和絳蟲,渦蟲獨特的蛋白酶的功能體現(xiàn)在諸如運動,與神經(jīng)系統(tǒng)發(fā)生相關(guān)的生物粘附等方面。這些差別與渦蟲和兩類寄生蟲之間的生理特點和生活環(huán)境的差異相一致:渦蟲營自由生活,運動機(jī)能和神經(jīng)系統(tǒng)等方面更加發(fā)達(dá),而吸蟲和絳蟲因為.寄生,這些機(jī)能相對退化,因此渦蟲的蛋白酶系統(tǒng)比吸蟲和絳蟲更加發(fā)達(dá)。兩類同是寄生蟲的吸蟲和絳蟲之間的比較結(jié)果表明:它們各自特有的蛋白酶在功能上也有所不同,但都是參與基本的生命活動相關(guān)的蛋白酶。同屬于吸蟲的血吸蟲與華支睪吸蟲相比,蛋白酶數(shù)目和種類都很相似,這與它們較近的親緣關(guān)系及相似的生活方式是一致的。對吸蟲類降解組的進(jìn)一步比較分析發(fā)現(xiàn),血吸蟲蛋白酶發(fā)生了 一系列與該生物特定的寄生生活相關(guān)的適應(yīng)性進(jìn)化,主要體現(xiàn)在與消化和入侵兩個相關(guān)方面。吸蟲為了高效消化血紅蛋白,參與消化的組織蛋白酶B、D發(fā)展出新的酶亞型,而且有的酶分子亞型有復(fù)制現(xiàn)象,產(chǎn)生了了多個拷貝,選擇壓力分析發(fā)現(xiàn)組織蛋白酶D明顯受到正選擇作用。華支睪吸蟲參與消化的天冬氨酸蛋白酶A01家族有擴(kuò)增現(xiàn)象。入侵宿主方面,血吸蟲產(chǎn)生了幾個新酶:S01家族中的彈性蛋白酶和尾蚴蛋白酶,M08家族中的入侵蛋白酶。而絳蟲降解組中以丟失一些酶為主,基因組間的比較發(fā)現(xiàn)絳蟲發(fā)生了相關(guān)酶的基因甚至整個代謝途徑的丟失。在氨基酸和核酸代謝方面,絳蟲和吸蟲一樣均丟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.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：Q95
本文編號：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.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：Q95
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