三株产甲烷细菌表面层研究

STUDY ON THE SURFACE LAYERS OF THREE METHANOGENS

用电子显微镜的负染色技术，对史氏甲烷短杆菌Ｈ１３（ Ｍｅｔｈａｎｏｂｒｅｖｉｂａｃｔｅｒｓｍｉｔｈｉｉ Ｈ１３）、嗜热甲酸甲烷杆菌ＣＢ１２（ Ｍｅｔｈａｎｏｂａｃｔｅｒｉｕｍ ｔｈｅｒｍｏｆｏｒｍｉｃｉｃｕｍ ＣＢ１２） 、拉布雷甲烷粒菌Ｚ（ Ｍｅｔｈａｎｏｃｏｒｐｕｓｃｕｌｕｍ ｌａｂｒｅａｎｕｍ Ｚ） 的表面结构观察比较结果表明：史氏甲烷短杆菌Ｈ１３ 和嗜热甲酸甲烷杆菌ＣＢ１２ 的表面层由规则排列的四边形亚单位组成；前者每个亚单位直径为５～７ ｎｍ ，亚单位之间的中心距离为５ ～８ ｎｍ ，后者亚单位直径为９～１２ ｎｍ ，亚单位之间的中心距离为１１～１４ ｎｍ ．拉布雷甲烷粒菌Ｚ的表面层是条纹和颗粒状或丝状组成的网状结构．每根条纹宽３～４ ｎｍ ，条纹之间的距离为６～８ ｎｍ ．３ 株产甲烷细菌的表面层各不相同，其中嗜热甲酸甲烷杆菌ＣＢ１２ 和拉布雷甲烷粒菌Ｚ的表面层结构十分独特，明显不同于已报道的产甲烷细菌和古细菌的表面层结构．

The surface layers of three strains of methanogens,including Methanobrevibacter smithii H13, Methanobacterium thermoformicicum CB12 and Methanocorpusculum labreanum Z,were examined by negative staining preparation with electron microscope.Two types of crystallin protein array could be observed in the three methanogens.The surface layers of Methanobrevibacter smithii H13 and Methanobacterium thermoformicicum CB12 were tetragonally arranged by protein subunits.The diameter of each subunit of the former was 5～7 nm,and center to center space of subunits was 9～12 nm,and those of the latter were 9～12 nm and 11～14 nm,respectively.The surface layer of Methanocorpusculum labreanum Z was reticulate and consisted of a series of striae and irregular granules.Each stria was 3～4 nm wide and the distance between striae was 6～8 nm.This study showed that the surface layers of the three methanogens were different and also different from those of the reported methanogens and archaebacteria.