【摘要】 介绍了共生菌固氮涉及的动物和微生物类群、动物共生菌固氮的性质和机理。应用乙炔还原法和固氮酶基因检测等研究表明,所涉及的动物有7门13纲23目50科99属174种。动物肠道具有丰富的微生境,供不同生理需求的固氮菌生长发育,所蕴含的共生固氮菌类群也十分丰富,涵盖植物共生固氮菌、植物内生固氮菌、植物根际固氮菌、自生固氮菌等生态类型。一般认为动物共生固氮菌来源于环境,其性质属于联合共生固氮。动物共生固氮菌一般与其他共生生物形成复合体,以满足固氮过程中对电子和质子供体、能量供给、固氮酶活性保护以及氨阻遏解除等方面的需求。动物共生菌固氮产物氨的同化也需要多种共生物的协同作用,可能通过谷氨酰胺合成酶/谷氨酸合成酶等途径。总体上,食物氮、非蛋白氮和共生菌固氮相互协调,形成营养和解毒的代谢网络,共同维持动物体内氮素营养的动态平衡,并对未来研究提出展望。更多还原

【Abstract】 In this paper, we reviewed the symbiotic association between animals and nitrogen-fixing bacteria and the nature and mechanism of symbiosis. A total of 174 species of animals in 7 phyla, 13 classes, 23 orders, 50 families, and 99 genera were evaluated in this paper, and they were found to use acetylene reduction and gene detection of nitrogenase. The animal gut has a rich microbial environments, which meets the growth and development demands of nitrogen-fixing bacteria. As a result, the animal guts were rich with symbiotic nitrogen-fixing bacteria of different ecological types, such as those that are symbiotic with plants, those that are endophytic diazotrophs, nitrogen-fixing bacteria from the rhizospheres, and Azotobacter. It is generally believed that animal symbiosis with nitrogen-fixing bacteria stems from the environment. The nature of animal symbiosis with nitrogen-fixing bacteria belongs to associative nitrogen fixation. Nitrogen-fixing bacteria that are symbiotic with animals coordinate with other symbiotic organisms to meet the needs of electron and proton donors, energy supply, nitrogenase activity protection, and ammonia repression relief during nitrogen fixation. The assimilation of ammonia during nitrogen fixation is also involved in the synergies of different symbiotic organisms and might be carried out through the pathway of glutamine synthetase/glutamate synthetase.In general, food nitrogen, non-protein nitrogen, and nitrogen-fixing symbiotic bacteria coordinate with each other to form a metabolic network of nutrition and detoxification to maintain the homeostasis of nitrogen nutrition in animals. The prospects of nitrogen fixation of animal symbionts were also identified in this paper.更多还原