特征菌筛选及其协同远盲蚓活化土壤锌镉的生物化学机制

Although it is considered as an important theoretical basis for the earthworm bioremediation technology in polluted soil, the activition mechanism of earthworms on heavy metals is not completely clear until now. It is supposed that soil microorganism could take part in this process by the synergistic effects with earthworm.However,are there some special strains in such a process? And how could these strains act in synergy with earthworms on an increase of heavy metal bioavailability in soil? They are both unwell known..In this project, three ecological species of Amynthas sp. are introduced into two kinds of soil contaminated by Zn and Cd in the lab. Microbial population characteristics and Zn/Cd speciation are analyzed by those methods of soil science,microbiology,molecular biology and metallomics. The relationship between microbial populations and heavy metal speciation are evaluated in depth, while particular functional strains are selected according to their significant influences.Moreover, GFP-tagged particular strains are inoculated into sterile soil with earthworm together again in the lab. The dynamic process and the features of its' temporal and spatial variation are observed by the fluorescence microscopy; while its relationships with heavy metal speciation, those related physical and chemical properties are analyzed as well. It aims to further reveal effects of particular strains on the activition biochemical mechanism of earthworm on heavy metal bioavailability..The project provides new ideas for understanding in-depth of the activition mechanism of earthworm on heavy metal bioavailability. It also helpful to provide scientific basis for the application of earthworm-bioremediation technology in soil contaminated by heavy metal.

"蚯蚓活化土壤重金属的机制"是构建蚯蚓生物修复技术的至关重要的理论依据，然而其至今尚未阐明。与蚯蚓互惠共生的土壤微生物可能影响这一机制。但是，这一过程中是否存在特征菌？其怎样协同蚯蚓活化土壤重金属？目前仍不清楚。.本项目通过室内微宇宙模拟试验，接种三种生态类型远盲蚓于两种锌镉污染特征土壤进行动态观测。运用土壤学、微生物学、分子生物学和金属组学等多种技术，探明不同类型蚯蚓的消化作用对土壤的微生物种群和锌镉形态转化特征的影响，深入剖析二者的相互关系，进而筛选出特殊功能菌种。通过绿色荧光蛋白法标记特征菌，将其与蚯蚓一同回接于无菌土壤进行48h动态培养，重点观察菌种在蚓体内和土壤中生长、聚集的时空变化特征，建立菌种、锌镉形态以及相关理化特征变化的关联，进一步揭示特征菌协同远盲蚓活化土壤锌镉的生物化学机制。.本研究将从新的角度阐明蚯蚓活化重金属的机制，为应用新型蚯蚓修复污染土壤技术提供科学依据。

土壤微生物在“蚯蚓活化土壤重金属的机制”中起了重要作用。本项目设置多组试验，将不同生态类型远盲蚓接种于污染土壤进行观测，研究其对土壤理化和微生物特征的影响，并探明微生物种群和金属形态转化的关系。研究结果显示不同类型蚯蚓的消化作用提高土壤的微生物种群活性、改变其种群结构和增加生物多样性。筛选出特殊功能菌种鞘氨醇杆菌属(Sphingobacterium sp.)、金黄杆菌属(Chryseobacterium sp.)、香味菌属(Myroides sp.)、芽孢杆菌属(Bacillus sp.)、假单胞杆菌属(Pseudomonas sp.)和丛毛单胞菌属(Comamonas sp.)等与金属迁移转化相关菌种。试验进一步通过菌种、锌镉形态以及相关理化特征等变化的相互关联，揭示了微生物协同远盲蚓活化土壤锌镉的生物化学机制。本研究阐明蚯蚓活化重金属的机制，为应用新型蚯蚓修复污染土壤技术提供科学依据。