發(fā)布時(shí)間：2018-05-18 11:17

  本文選題：黑斑側(cè)褶蛙 + 抗菌肽��； 參考：《東北林業(yè)大學(xué)》2016年碩士論文

【摘要】：抗菌肽是兩棲類免疫系統(tǒng)的第一道防線,抗菌肽通常具有較高的多樣性。關(guān)于多樣性形成的機(jī)制已提出三類機(jī)制：抗菌肽基因不斷復(fù)制產(chǎn)生新的座位,堿基具有高于其他基因的突變率,并受正選擇的驅(qū)動(dòng)。但是這些過程是如何實(shí)現(xiàn)的還不能很好的解釋。我們研究發(fā)現(xiàn),野外環(huán)境下黑斑側(cè)褶蛙(Pelophylax nigromaculata)的抗菌肽譜中Temporin-1N表達(dá)量最高,且受到強(qiáng)烈的負(fù)選擇作用,而其他的抗菌肽則受到不同程度的中性或正選擇作用。我們推測(cè)Temporin-1N在整個(gè)抗菌譜中起著支柱性作用,為其他抗菌肽減輕了選擇壓力,促進(jìn)其實(shí)現(xiàn)快速進(jìn)化。為了驗(yàn)證這一推測(cè),本研究以1只黑斑側(cè)褶蛙為材料,通過染色體步移技術(shù)解析Temporin-1N抗菌肽的基因及5'-UTR的結(jié)構(gòu),并對(duì)其表達(dá)速度及進(jìn)化機(jī)制進(jìn)行研究。主要結(jié)果如下：1. Temporin-1N抗菌肽的基因結(jié)構(gòu)：5'-UTR+編碼信號(hào)肽和部分酸性前肽的外顯子1+內(nèi)含子+編碼剩余酸性前肽和完整成熟肽的外顯子2+3'-UTR。2.一只個(gè)體中發(fā)現(xiàn)4個(gè)不同的Temporin-1N基因,4個(gè)基因的成熟肽編碼區(qū)未發(fā)現(xiàn)堿基突變,顯示極低的遺傳多樣性。3.基于cDNA序列的預(yù)測(cè)表明,黑斑側(cè)褶蛙的Temporin-1N由15個(gè)氨基酸殘基組成,為螺旋結(jié)構(gòu)的堿基陽離子肽,與其他物種Temporin理化性質(zhì)相似,推測(cè)其具有廣譜且高效的抗菌活性。4. Neural Network Promoter Prediction預(yù)測(cè)顯示,Temporin-1N基因5'-UTR和內(nèi)含子區(qū)均含有多個(gè)啟動(dòng)子區(qū),提示其有快速轉(zhuǎn)錄的能力。5. TRANSFAC預(yù)測(cè)顯示,該基因5'-UTR和內(nèi)含子區(qū)均含有若干個(gè)TATA-box、GC-box和CAAT-box真核生物基礎(chǔ)順式作用元件和調(diào)控免疫特異性表達(dá)及組織特異性表達(dá)相關(guān)的轉(zhuǎn)錄因子結(jié)合位點(diǎn),預(yù)示Temporin-1N基因可參與多種生理過程。上述結(jié)果表明,Temporin-1N具有廣譜的抗菌活性,由多個(gè)基因編碼,每個(gè)基因具有快速轉(zhuǎn)錄能力,并參與諸多生理過程,提示Temporin-1N具備在整個(gè)抗菌肽譜中起著支柱性作用的條件,預(yù)示著正因其庇護(hù),其他抗菌肽才能在輕微選擇壓力下快速積累突變,從而實(shí)現(xiàn)快速進(jìn)化,推動(dòng)多樣性的形成。
[Abstract]:Antimicrobial peptides are the first line of defense of amphibian immune system. Antimicrobial peptides usually have high diversity. Three mechanisms have been proposed for the formation of diversity: the antimicrobial peptide gene replicates to produce new loci, the base has a higher mutation rate than other genes, and is driven by positive selection. But how these processes are implemented is not well explained. We found that in the field, the Temporin-1N expression of Pelophylax nigromaculata was the highest and strongly negative selection, while the other antimicrobial peptides were neutral or positive selective to varying degrees. We speculate that Temporin-1N plays a columnar role in the whole antimicrobial spectrum, which reduces the selection pressure and promotes the rapid evolution of other antimicrobial peptides. In order to verify this hypothesis, the gene of Temporin-1N antimicrobial peptide and the structure of 5'-UTR were analyzed by chromosome step technique, and the expression rate and evolutionary mechanism of 5'-UTR were studied. The main results are as follows: 1. The gene structure of Temporin-1N antimicrobial peptide encoding signal peptide and exon 1 of partial acidic propeptide encodes exon 23 of the remaining acidic propeptide and the exon 23 of the intact mature peptide. Four different Temporin-1N genes were found in one individual, and no base mutation was found in the mature peptide coding region of 4 genes, indicating very low genetic diversity. The prediction based on cDNA sequence showed that the Temporin-1N of Rana nigra was composed of 15 amino acid residues and was a base cationic peptide with helical structure, which was similar to the physical and chemical properties of other species Temporin, and its antibacterial activity was presumed to be broad spectrum and high efficiency. 4. Neural Network Promoter Prediction prediction showed that both the 5'-UTR and intron regions of the gene had multiple promoter regions, indicating that they had the ability of rapid transcription. TRANSFAC prediction showed that both the 5'-UTR and intron regions of the gene contained several basic cis-acting elements of TATA-boxbox and CAAT-box eukaryotes and transcription factor binding sites related to the regulation of immuno-specific expression and tissue specific expression. It is suggested that Temporin-1N gene may be involved in many physiological processes. These results suggest that Temporin-1N has broad-spectrum antibacterial activity and is encoded by multiple genes. Each gene has a rapid transcription ability and participates in many physiological processes, suggesting that Temporin-1N has the condition of playing a columnar role in the whole antimicrobial peptide spectrum. It is indicated that other antimicrobial peptides can rapidly accumulate mutations under mild selection pressure and thus achieve rapid evolution and promote the formation of diversity.
【學(xué)位授予單位】：東北林業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：Q953

【相似文獻(xiàn)】

相關(guān)期刊論文 前8條

1 應(yīng)浩;陳曉萍;陳曉虹;;河南新鄉(xiāng)段衛(wèi)河水對(duì)黑斑側(cè)褶蛙早期胚胎發(fā)育的影響[J];四川動(dòng)物;2008年05期

2 鄭榮泉,杜衛(wèi)國,壽鹿;黑斑側(cè)褶蛙的兩性異形和雌性繁殖特征[J];動(dòng)物學(xué)雜志;2002年04期

3 季菁菁;夏睿;李曉平;蘭天明;徐艷春;;黑斑側(cè)褶蛙5類抗菌肽基因的克隆及其成熟肽理化性質(zhì)的預(yù)測(cè)[J];野生動(dòng)物;2012年03期

4 金晨晨;瞿康山;張志強(qiáng);;黑斑側(cè)褶蛙肥滿度及臟器重量的性別和季節(jié)差異[J];四川動(dòng)物;2014年01期

5 賈迪;李丕鵬;王勇;周正彥;蘇若萍;韓琳;陸宇燕;;3種無尾兩棲類腎形態(tài)結(jié)構(gòu)及其對(duì)環(huán)境的適應(yīng)性[J];動(dòng)物學(xué)雜志;2011年02期

6 張雄飛,周開亞,常青;中國大陸黑斑側(cè)褶蛙基于mtDNA控制區(qū)序列的種群遺傳結(jié)構(gòu)[J];遺傳學(xué)報(bào);2004年11期

7 郭靜;侯國賓;孟慶雄;宋玉竹;;黑斑側(cè)褶蛙抗菌肽Pelophylaxin 2PG的cDNA篩選與性質(zhì)研究[J];昆明理工大學(xué)學(xué)報(bào)(自然科學(xué)版);2012年03期

8 ;[J];;年期

相關(guān)博士學(xué)位論文 前2條

1 王超飛;黑斑側(cè)褶蛙和中華大蟾蜍的特征、功能、力學(xué)特性及其仿生分析[D];吉林大學(xué);2011年

2 龔杰;黑斑側(cè)褶蛙SSR位點(diǎn)分離及種群遺傳結(jié)構(gòu)分析[D];浙江大學(xué);2012年

相關(guān)碩士學(xué)位論文 前8條

1 樊捷;黑斑側(cè)褶蛙形態(tài)地理變異的研究[D];東北林業(yè)大學(xué);2015年

2 來冉冉;黑斑側(cè)褶蛙Temporin-1N抗菌肽基因結(jié)構(gòu)與進(jìn)化方式的研究[D];東北林業(yè)大學(xué);2016年

3 陳賽鶴;造紙工業(yè)廢水對(duì)黑斑側(cè)褶蛙皮膚影響的定量組織學(xué)研究[D];東北林業(yè)大學(xué);2016年

4 王昊;低溫脅迫下東北林蛙和黑斑側(cè)褶蛙組織可溶性蛋白適應(yīng)性應(yīng)答[D];東北林業(yè)大學(xué);2009年

5 張華;中國大陸黑斑側(cè)褶蛙種群的線粒體DNA分岐與建群歷史：上新世隔離事件與獨(dú)立的避難所擴(kuò)張[D];南京師范大學(xué);2005年

6 張雄飛;中國大陸黑斑側(cè)褶蛙種群遺傳結(jié)構(gòu)及與金線側(cè)褶蛙的種間遺傳變異[D];南京師范大學(xué);2004年

7 張國強(qiáng);ISSR分子標(biāo)記揭示黑斑側(cè)褶蛙中國種群的遺傳結(jié)構(gòu)和遺傳多樣性[D];南京師范大學(xué);2005年

8 孫啟鵬;基于微衛(wèi)星與線粒體控制區(qū)探討長江流域黑斑側(cè)褶蛙種群遺傳結(jié)構(gòu)[D];浙江大學(xué);2013年

，

本文編號(hào)：1905626