不同分离方法对子实体形成和粘细菌分离的影响

Effects of different methods on the formation of fruiting bodies and isolation of myxobacteria

【目的】基于模拟原位环境策略、可培养粘细菌的营养策略及细菌互作网络,改良分离培养基,以提高分离粘细菌的多样性。【方法】通过添加土壤浸提液、使用不同种类的诱导菌和改变诱导菌的接种方式设置分离方法,同时以传统的分离方法作对照。【结果】改良的分离方法比对照组诱导出了更多粘细菌子实体种类,采自4个地区的9份样品共分离纯化出40株粘细菌,按形态学和分子生物学,将其归类于原囊菌属(Archangium)、珊瑚菌属(Corallococcus)、软骨霉状菌属(Chondromyces)、粘球菌属(Myxococcus)、侏囊菌属(Nannocystis)、多囊菌属(Polyangium)、匣状球菌属(Pyxidicoccus)。【结论】与传统分离方法相比,添加土壤浸提液,诱导菌点接法能大大提高诱导出的粘细菌子实体种类的数目,革兰氏阳性菌和革兰氏阴性菌作为诱导菌对子实体种类影响较小,但是也发现革兰氏阳性菌特异性诱导出的子实体。虽然本研究通过对分离培养基的改良大大增加了子实体种类,但是纯化出的粘细菌种类远少于观察到的子实体种类,说明除改良分离方法外,还需进一步研究粘细菌的纯化方法,提高分离所得粘细菌的多样性,获取更多粘细菌新资源。

[Objective]We modified myxobacterial isolation methods based on the in-situ simulation,the nutritional requirements of cultured myxobacteria and myxobacterial interactions with bacteria inferred from co-occurrence network,to obtain more cultured myxobacteria.[Methods]We set experiment by adding soil extract into isolation medium,using Gram-positive bacteria as bait and changing the inoculation method of bait,with traditional methods as control.[Results]More types of myxobacteria fruiting bodies were induced by the modified methods than traditional methods.A total of 40 myxobacteria strains were isolated from 9 soil samples including subtropical forest soil,saline-alkaline soil,and wetland sediment.The isolated myxobacteria were from genera of Archangium,Chondromyces,Corallococcus,Myxococcus,Nannocystis,Polyangium and Pyxidicoccus.[Conclusion]Compared with traditional methods,the addition of soil extract and bait inoculated by spotting can obviously increase the types of fruiting bodies.Although the strains of bait showed little effect on the fruiting bodies,Gram-positive bacteria could induce specific fruiting bodies.In this study,we modified isolation methods of myxobacteria and greatly increased the types of fruiting bodies,but the number of purified myxobacteria were far less than that of fruiting bodies observed,indicating that the improvement of purification is required to obtain more cultured myxobacteria.