黄芪生真菌的分离纯化及发酵产物活性的研究

发布时间：2022-11-05 02:36

　　目的从黄芪根、叶中分离内生真菌,并对其抗菌、总还原力和α-葡萄糖苷酶抑制活性进行评价。方法对黄芪的根、叶进行表面消毒、无菌处理,采用组织块培养分离和亚培养的方法分离纯化黄芪根、叶内生真菌。用形态学方法和分子生物学方法对纯化后的菌落进行鉴定。对发酵液的提取物进行了抗菌、还原力和-葡萄糖苷酶抑制等多种生物活性测试。采用滤纸圆盘法对四种指示菌进行抑菌活性筛选,并测定抑菌区的直径。采用铁氰化钾法和PNPG法测定了次生代谢产物α-糖苷酶的总还原力和抑制率。结果从黄芪根、叶中分离出72株内生真菌。根内生植物56种,叶内生植物16种。这些内生真菌首先通过研究其表面特征,然后通过分子生物学进行鉴定,并据此进行分类。抑菌区直径表明,乙酸乙酯提取物具有较好的抑菌活性。HQ_R-PDA13对四种菌株均具有较高的抑制活性。另外四种提取物对这四种菌株都有中度抑制作用。此外,16种提取物具有一定的抗氧化活性,其中HQ_L-PDA1具有最强的还原能力。10个样品的α-糖苷酶抑制率≥80%,最佳抑制率为HQ_R-SDA1 96.1。结论黄芪具有丰富的内生真菌... 

【文章页数】：70 页

【学位级别】：硕士

【文章目录】：
Abstract
摘要
Chapter 1 Introduction
    1.1 Literature review on Astragalus membranaceus
    1.2 Literature review on Root-Associated Bacterial diversityin Astragalus membranaceus
    1.3 Literature review on Endophytic Fungi
        1.3.1 Research status and definition of endophytic fungi
        1.3.2 Endophytic fungi-plant symbiosis
        1.3.3 Distribution of endophytic fungi in plants
        1.3.4 Biodiversity of endophytic fungi in plants
        1.3.5 Bioactivities of secondary metabolites isolated from endophyticfungi of medicinal plants
            1.3.5.1 Antimicrobial activities of microbial secondary metabolites
            1.3.5.2 Antioxidant activities of microbial secondary metabolites
            1.3.5.3 Inhibition ofα-glucosidase activities of microbial secondary metabolites
            1.3.5.4 Anti-cancer activities of microbial secondary metabolites
    1.4 Problems and prospects of secondary metabolites of endophytic fungi research
    1.5 Research content,purpose and significance
Chapter 2 Preliminary examination of the Endophytic bacterialComposition of Astragalus membranaceus
    2.1 Test materials
        2.1.1 Plant and soil samples
    2.2 Test method
        2.2.1 Sampling of plant and soil
        2.2.2 Characterization of soil sample
        2.2.3 High-thorough sequencing
        2.2.4 Bioinformatic analysis
    2.3 Results and discussion
        2.3.1.Physicochemical properties of the soil
        2.3.2.Diversity of the bacterial community
        2.3.3.Effects of soil physic-chemical factors on bacterialcommunity composition
        2.3.4.Analysis of the correlation of bacterial communities
    2.4 Discussion
    2.5 Summary
Chapter 3 Isolation and purification of endophytic fungi fromAstragalus membranaceus
    3.1 Test material
        3.1.1 Plant sample
        3.1.2 Reagents
        3.1.3 Instruments/Apparatus
        3.1.4 Culture media composition
    3.2 Test method
        3.2.1 Isolation and purification of endophytic fungi
        3.2.2 Preservation of endophytic fungi
        3.2.3 Morphological identification of endophytic fungi
        3.2.4 Molecular identification of endophytic fungi
    3.3 Results and Discussion
        3.3.1 Isolation,purification and preservation of endophytic fungi
        3.3.2 Morphological characteristics of endophytic fungiisolated from Astragalus membranaceus
            3.3.2.1 Growth pattern and surface morphology characteristics
            3.3.2.2 Microscopic identification of endophytic fungi isolatedfrom Astragalus membranaceus
        3.3.3 Molecular biology identification of endophytic fungi isolated fromAstragalus membranaceus
    3.4 Summary
Chapter 4 Antibacterial activities of secondary metabolitesisolated from endophytic fungi of Astragalus membranaceus
    4.1 Test Material
        4.1.1 Test strains
        4.1.2 Culture medium
        4.1.3 Reagents
        4.1.4 Instruments/Apparatus
    4.2 Test method
        4.2.1 Culture and fermentation of endophytic fungi
        4.2.2 Antibacterial activity test
    4.3 Results and Discussion
    4.4 Summary
Chapter 5 Antioxidant andα-glucosidase inhibition activity of secondaryMetabolites isolated from endophytic fungi of Astragalus membranaceus
    5.1 Test Materials
        5.1.1 Test samples
        5.1.2 Reagents
    5.2 Test method
        5.2.1 Determination of Total Reduction Force
        5.2.2 Screening ofα-glucosidase inhibition activity
    5.3 Results and Discussion
        5.3.1 Total Reductive Force
        5.3.2 Inhibition ofα-glucosidase
Discussion
Conclusion
References



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