Abstract：
Tetrahymenosis is caused by the ciliated protozoan Tetrahymena and is responsible for serious economic losses to the aquaculture industry worldwide. However, information regarding the molecular mechanism leading to tetrahymenosis is limited. In previous transcriptome sequencing work, it was found that one of the two β-tubulin genes in T. pyriformis was significantly expressed in infected fish, we speculated that β-tubulin is involved in T. pyriformis infecting fish. Herein, the potential biological function of the β-tubulin gene in Tetrahymena species when establishing infection in guppies was investigated by cloning the full-length cDNA of this T. pyriformis β-tubulin (BTU1) gene. The full-length cDNA of T. pyriformis BTU1 gene was 1873 bp, and the ORF occupied 1134 bp, whereas 5\' UTR 434 bp, and 3\' UTR 305 bp whose poly (A) tail contained 12 bases. The predicted protein encoded by T. pyriformis BTU1 gene had a calculated molecular weight of 42.26 kDa and pI of 4.48. Moreover, secondary structure analysis and tertiary structure prediction of BTU1 protein were also conducted. In addition, morphology, infraciliature, phylogeny, and histopathology of T. pyriformis isolated from guppies from a fish market in Harbin were also investigated. Furthermore, qRT-PCR analysis and experimental infection assays indicated that the expression of BTU1 gene resulted in efficient cell proliferation during infection. Collectively, our data revealed that BTU1 is a key gene involved in T. pyriformis infection in guppies, and the findings discussed herein provide valuable insights for future studies on tetrahymenosis.
摘要：
四膜病是由纤毛原生动物四膜虫引起的，对全球水产养殖业造成严重的经济损失。然而,有关导致四膜病的分子机制的信息有限。在以前的转录组测序工作中，研究发现，在感染的鱼中显著表达了木梨状芽孢杆菌中的两个β-微管蛋白基因之一，我们推测β-微管蛋白参与了梨状芽孢杆菌感染鱼类。在这里，通过克隆该T.pyriformisβ-微管蛋白（BTU1）基因的全长cDNA，研究了四膜虫物种在孔雀鱼中感染时β-微管蛋白基因的潜在生物学功能。梨状芽孢杆菌BTU1基因的cDNA全长为1873bp,ORF占1134个基点，而5UTR434bp，和3个UTR305bp，其poly（A）尾包含12个碱基。由梨状芽孢杆菌BTU1基因编码的预测蛋白质具有42.26kDa的计算分子量和4.48的pI。此外，对BTU1蛋白进行二级结构分析和三级结构预测。此外,形态学,Infriciature,系统发育,并对从哈尔滨某鱼类市场的孔雀鱼中分离出的梨状芽孢杆菌进行了组织病理学研究。此外，qRT-PCR分析和实验性感染实验表明，BTU1基因的表达导致感染期间细胞有效增殖。总的来说，我们的数据显示，BTU1是参与孔雀鱼中的T.pyriformis感染的关键基因，本文讨论的发现为未来对四膜病的研究提供了有价值的见解。
