【作者】 曹甲；

【导师】 刘朝良；

【作者基本信息】 安徽农业大学 ， 生物物理学， 2010， 硕士

【摘要】 蚕丝由丝胶和丝素两部分组成。丝胶主要是由中部丝腺合成,约占重量的25 %,包裹着丝素蛋白。丝素蛋白主要是在后部丝腺合成,是蚕丝中主要的组成部分,约占重量的70%。丝素重链(Fib-H)作为丝素蛋白中主要的组成部分,与丝素轻链(Fib-L)和P25蛋白以6∶6∶1的摩尔比组成复合体,构成丝素的基本结构单位。研究丝素重链对于提高蚕丝的产量和质量、生产有特殊用途的丝产品、提高蚕的抗病能力和抵抗不良环境的能力以及弄清物种之间的同源性与进化关系等方面具有重要的理论和实际应用价值。本研究利用反转录PCR的方法首次在柳蚕丝腺中获得了Fib-H基因的5’端序列,片段长2801bp,编码933个氨基酸,包含起始密码子ATG,具有野蚕Fib-H保守结构特征,经过与柞蚕、天蚕、樟蚕、印度柞蚕等昆虫的丝素基因对比,发现有高度的同源性,尤其与同为大蚕蛾科的樟蚕的关系最近。GenBank登录号:GU212855.1。利用半定量PCR对五龄期不同时间Fib-H基因的表达情况进行分析,结果表明:柳蚕幼虫5龄期第1日、第3日、第6日、第9日、第12日的后部丝腺中,Fib-H基因的表达量呈逐渐增加的趋势,与丝腺发育的生理特征相符合。通过对五龄期第1日、第3日、第6日、第9日、第12日中部丝腺、脂肪体等不同组织Fib-H基因的表达情况进行分析,发现Fib-H基因在中部丝腺中也存在一定程度的表达,且变化趋势大致是:低—高—低-高。脂肪体中未检测到该基因表达,表明Fib-H基因的表达具有组织特异性,这与早期的关于Fib-H基因的研究结果基本是一致的。更多还原

【Abstract】 Silk contains two main parts, sericin and fibroin.Sericin produced in mid-silk glang encapsulates fibroin which takes up 25% of the total weight. Fibroin produced in post-silk gland is the main part of silk which takes up 70% of the total weight.Fibroin-H as the main part of silk、fibroin-L and P25 with a 6:6:1 molar ratio make up the fundamental structural unit of fibroin.Rearch of fibroin-H has important theoretical and practical value. From theoretical sense, we can ascertain the homology and evolution relationship of different species. From practical possibilities ,we can increase output and quality of silk, produce special silk product,raise silkworm ablility of resistance to disease and the ability to resist bad environment and development new applications.This experiment cloned Fibroin-H gene sequence of the 5’flanking from Actias selene firstly. This sequence of 2801bp long contains start codon and encodes 933 amino acids with Fibroin-H conservative structural characteristics.We have found that the sequence has a high homology with that of Antheraea pernyi、Antheraea yamamai、Saturnia japonica、Anthereaea mylitta, especially Saturnia japonica.It shows the result is right.The accesssion number is GU212855.1. Through expression analysis of semi-quantitative PCR towards fibroin-H of different time in the fifth instar, we have found expession of fibroin-H from the first day,third day, sixth day, ninth day and twelfth day in the fifth instar of A.selene in post-silk gland increases day by day.It is credible.Through analysis we have detected fibroin-H from the first day,third day, sixth day, ninth day and twelfth day in the fifth instar of A.selene in mid-silk gland and the trend is:low-high-low-high.We have not detected fibroin-H in fat body.It shows expression of fibroin-H has organization specificity which is in accord with previous study.更多还原