固着目缘毛类纤毛虫部分类群的分子系统学研究

发布时间：2018-06-20 04:39

  本文选题：纤毛虫 + 缘毛类　； 参考：《烟台大学》2017年硕士论文

【摘要】：纤毛虫隶属于原生生物界,纤毛门,是形态最复杂和最高等的单细胞真核生物。纤毛虫不仅在生态圈内的能量传递过程中起着重要的作用,同时也是微食物网的重要组成部分。纤毛虫作为一种良好的模式生物被广泛应用于细胞生物学、分子生物学、和分子系统学等科学领域中,且在生物的起源与进化等方向上具有独特的研究地位。本研究以固着缘毛类纤毛虫为研究对象,通过多基因(核糖体小亚基基因SSU rDNA,ITS1-5.8S-ITS2转录间隔区基因,核糖体大亚基基因LSU rDNA)测序,进行了相关的分子系统学研究,分析固着目缘毛类纤毛虫部分类群的系统发育关系,并建立了一个新种。主要研究成果如下:1.共新测得68条序列,包括31条SSU rDNA序列,21条ITS1-5.8S-ITS2转录区序列,16条LSU rDNA序列,涉及4个科,6个属,32个种。所有序列已提交至GenBank数据库,文章发表后可释放。2.利用蛋白银染色结合分子测序的鉴定方法建立了一个新种。主要研究结论为:1.分析系统发育树后得出进化假设和观点:(1)在聚缩虫科中,聚缩虫属是祖先型,完整分布的肌丝是祖征;(2)裂肌虫属以及累枝虫属都是由聚缩虫属的肌丝基因的不表达或不完全表达进化而来,拟聚缩虫属也是由聚缩虫属进化而来;(3)累枝虫科是多源进化的,在基部进化枝的累枝虫科纤毛虫应是固着缘毛类的祖先型;(4)鞘居虫科是单源发生的,且应是固着缘毛类的一种祖先种;(5)如果要研究更准确的缘毛类纤毛虫进化史,则需要有包含更多更完整的多基因序列的数据集。2.建立一个新种——盐靴纤虫Cothurnia salina。形态学定义描述如下:虫体为细长的柱形,大小80~98×12~19μm。壳室筒状,底部为双层结构。柄极短,约?在壳室内。大核呈蠕虫状,纵向排列。一个伸缩泡位于腹位。虫体表膜有明显的横纹,从反口纤毛环到口围缘有62~73条,从反口纤毛环到帚胚有32~38条。第3小膜由两列相互平行近等长的动基列组成,动基列下端终止于小膜1和小膜2之间。超盐水种(盐度120‰)。本研究首次完成对固着缘毛类内部系统地位不明确的纤毛虫之间的分子系统学分析,并完善了GenBank中该类群的分子数据库;首次用现代分类学方法完整研究并报道了一种靴纤虫属纤毛虫,增加了该属的物种多样性及分子数据。
[Abstract]:Ciliates belong to protozoa and cilium phylum. They are the most complex and advanced unicellular eukaryotes. Ciliates not only play an important role in the energy transfer in the ecosphere, but also play an important role in the microfood web. Ciliates, as a good model organism, have been widely used in cell biology, molecular systematics and other scientific fields, and have a unique position in the origin and evolution of organisms. In this study, the molecular phylogeny of ciliate ciliates was studied by sequencing polygenes (ribosomal small subunit gene SSU rDNA-ITS1-5.8S-ITS2 transcriptional spacer gene, ribosomal large subunit gene LSU rDNA). The phylogenetic relationship of some groups of ciliates was analyzed and a new species was established. The main research results are as follows: 1. A total of 68 new sequences were obtained, including 31 SSU rDNA sequences, 21 ITS1-5.8S-ITS2 transcriptional region sequences and 16 LSU rDNA sequences, involving 32 species, 6 genera and 4 families. All the sequences were submitted to the GenBank database and released after the article was published. A new species was established by using the method of protein silver staining and molecular sequencing. The main conclusion is: 1: 1. After analyzing the phylogenetic tree, the evolutionary hypothesis and viewpoint were obtained. (1) in the family of pyramidaceae, the genus pyrola is an ancestral type. The complete distribution of myofilms is Echinotrichidae 2) and the genus Cladosporus evolved from the non-expression or incomplete expression of the myofilament genes of the genus Polycystis, and the genus Polycystis was evolved from the genus Polycystis, and the family Cladosporidae evolved from multiple sources. If we want to study the evolution history of ciliates more accurately, they should be the ancestral type of ciliates that are fixed at the base of their branches. (4) the sphingophoraceae is a monogeny, and it should be an ancestor species of the family Ciliformis, which is fixed on the fringes, if we want to study the evolution history of ciliates more accurately. A data set containing more complete polygenic sequences. 2. 2. A new species, Cothurnia salinina, was established. The morphological description is as follows: the insect is a slender column with a size of 80 ~ 98 脳 12 ~ (19) 渭 m. The shell chamber is cylindrical and the bottom is a double-layer structure. The handle is very short, about? In the shell room. The large nuclei are wormlike and arranged longitudinally. A telescopic bubble is located in the abdomen. There were obvious transverse lines on the surface membrane of the insect, with 622 ciliates from the reactile cilium to the perioral rim, and 32, 38 from the reactile ciliate ring to the broom embryo. The third membrane consists of two parallel and nearly equal length moving bases, the lower end of the moving base terminates between the small membrane 1 and the small membrane 2. Superbrine species (salinity 120 鈥，

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