粘质沙雷氏菌的电镜观察

Electron Microscopic Observations On Serratia Marcescens

用扫描电镜和透射电镜对粘质沙雷氏菌(Serratia marcescens)的临界点干燥标本和负染标本作了观察,均可见到细胞表面常有一至二个直径为0.12～0.24μm的颗粒。在超薄切片中颗粒则有两种不同的结构:一种是外膜泡(Outer membrane vesicle);另一种是致密体(Dense body)。致密体可能是一种分泌性颗粒,它既不是内部的贮存物,也不似外部进来的异物。它们看来形成于细胞质内后分泌到细胞外。在细菌中这是一种罕见现象。有关致密体的化学性质和功能尚不清楚。文中指出粘质沙雷氏菌的纲胞表面也具有茂密的菌毛(Pili)。

The critical-point drying/negative staining samples of Serratia marcescens cells were observed by SEM/TEM. One or two granules 0.12-0,24μm in diameter were seen on the cell surface in both samples. In ultrathin sections granules possess two different kinds of structures: One is a Outer-membrane vesicle: another is a Dense body. The Dense body might be a secretory granule, neither like an internal store nor like an external foreignstuff. It seemed that they were formed in the cytoplasm and secreted out of the cell. They appeared to be a rare phenomenon in bacteria. the chemical composition and physiological function of the Dense body are not known. this paper also presented evidence of thick Pili existing on the cell surface of Serratia marcescens.