Prediction and Characterization of A Cationic Arginine-rich

发布时间：2022-07-03 22:03

　　抗菌肽（AMPs）被视为植物防御系统的一部分,是一种可抑制多种植物病原菌的活性物质。从细菌到植物,抗菌肽可以存在于所有形式的生命中。SM-985是从大刍草（Zea mays ssp.mexicana）c DNA文库中分离的阳离子抗菌肽。使用具有不同算法的计算预测服务器来筛选大刍草c DNA文库中的抗菌肽,并且预测结果表明,SM-985具有高概率为抗菌肽。SM-985是一种富含精氨酸的肽,由21个氨基酸组成（分子量:2671.06 Da）,作为抗菌肽其物理化学性质非常理想,净电荷（+8）,疏水率23%,Boman指数5.19 kcal/mol,等电点12.95。SM-985肽具有两亲性α-螺旋构象。SM-985对6种植物病原细菌具有抗菌活性,对革兰氏阳性指示菌Clavibacter fangii,C.michiganesis ssp.michiganesis和B.subtilis 168的MIC为8μM,MBC为16μM;SM-985对革兰氏阴性指示菌Pseudomonas syringae pv.tomato DC3000,Ralstonia solanacearum,Xanthomo... 

【文章页数】：102 页

【学位级别】：硕士

【文章目录】：
摘要
Abstract
List of abbreviations
1 INTRODUCTION
    1.1 Literature review
        1.1.1 Teosinte as its relationship with maize
        1.1.2 Complementary DNA(c DNA)library
        1.1.3 Antimicrobial peptides(AMPs)
        1.1.4 Prediction of AMPs
        1.1.5 Different techniques of AMPs isolation
        1.1.6 Antimicrobial activity
        1.1.7 AMPs and plant protection
    1.2 Objectives of the study
2 MATERIALS AND METHODS
    2.1 Construction of induced c DNA library
        2.1.1 The preparation of teosinte c DNA
        2.1.2 Cloning of teosinte c DNAs
    2.2 Screening of c DNA library and bioinformatic analysis
        2.2.1 c DNAs sequencing and analysis
        2.2.2 In silico prediction-based screening for AMPs and bioinformatic analysis
    2.3 In vitro antimicrobial activity
        2.3.1 SM-985 peptide
        2.3.2 Minimal Inhibition Concentration(MIC)and Minimal Bactericidal Concentration(MBC)assays
        2.3.3 Minimal Lethal Concentration(MLC)assay
        2.3.4 Cell membrane integrity assay
    2.4 FITC-Labeled-SM-985 peptide
    2.5 In vivo antimicrobial activity assay
    2.6 Scanning Electron Microscopy(SEM) &Transmission Electron Microscopy assays(TEM)
        2.6.1 Scanning Electron Microscopy
        2.6.2 Transmission Electron Microscopy
    2.7 Influence of calcium chloride on SM-985 antimicrobial activity
3 RESULTS
    3.1 Construction of c DNA library
    3.2 In silico AMP prediction and characteristics of SM-989 peptide
    3.3 In vitro antimicrobial activity
        3.3.1 Determination of MICs and MBCs of SM-985 peptide
        3.3.2 The MLC of SM-985 peptide causes complete death for all bacterial indicators
        3.3.3 SM-985 increases the cell membrane permeability
    3.4 SM-985 localization
        3.4.1 FITC-Labeled SM-985 peptide interacts with bacterial cell membrane
        3.4.2 FITC-SM-985 maintains the antimicrobial activity
    3.5 In vivo antimicrobial activity
    3.6 SM-985 causes distinct damage to the bacterial cell membrane
    3.7 Calcium chloride inhibits the SM-985 antimicrobial activity
4 DISCUSSION
5 CONCLUSIONS,SIGNIFICANCE,AND RESEARCH PROSPECTS
    5.1 Conclusions
    5.2 Significance
    5.3 Research prospects
References
Appendices
Acknowledgments



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