Department of Biological Engineering, Seokyeong University, Seoul 136-704, Republic of Korea.
J Microbiol. 2009 Dec;47(6):721-7. doi: 10.1007/s12275-009-0146-2. Epub 2010 Feb 4.
A bacterium growing inside yeast cytoplasm was observed by light microscope without staining. The bacterium was separately stained from yeast cell by a fluorescent dye, 4',6-diamidino-2-phenylindole (DAPI). The bacterium actively moved inside yeast cytoplasm and propagated in company with the yeast growth. The bacterium was separated from the yeast cytoplasm by selective disruption of yeast cells and the yeast without the intracellular bacterium (YWOB) was obtained by selective inactivation of bacterial cells. The yeast and the intracellular bacterium were identified as Candida tropicalis and Microbacterium sp., respectively. The length of Microbacterium sp. and C. tropicalis measured with SEM image was smaller than 0.5 microm and was larger than 5 microm, respectively. The yeast with the intracellular bacterium (YWIB) grew in a starch-based medium but the YWOB was not C. tropicalis has neither extracellular nor intracellular saccharification enzyme. Glucose was produced from starch by the extracellular crude enzyme (culture fluid) of Microbacterium sp. YWIB produced significantly more ethanol from glucose than YWOB but did not from starch. Conclusively, C. tropicalis is thought to catabolize starch dependent upon Microbacterium sp. growing in its cytoplasm and furnish stable habitat for the Microbacterium sp.
在不染色的情况下，用光学显微镜观察到在酵母细胞质内生长的细菌。该细菌通过荧光染料 4',6-二脒基-2-苯基吲哚 (DAPI) 从酵母细胞中被单独染色。该细菌在酵母细胞质内活跃移动，并与酵母生长一起繁殖。通过选择性破坏酵母细胞，将细菌与酵母细胞质分离，获得了没有细胞内细菌的酵母（YWOB）。酵母和细胞内细菌分别被鉴定为热带假丝酵母和微杆菌。用扫描电子显微镜 (SEM) 图像测量的微杆菌和热带假丝酵母的长度小于 0.5 微米，分别大于 5 微米。有细胞内细菌的酵母（YWIB）在淀粉为基础的培养基中生长，但 YWOB 不是热带假丝酵母既没有细胞外也没有细胞内糖化酶。葡萄糖由微杆菌的细胞外粗酶（培养液）从淀粉中产生，YWIB 从葡萄糖中产生的乙醇明显多于 YWOB，但从淀粉中则不然。综上所述，认为热带假丝酵母依赖于在其细胞质内生长的微杆菌来分解淀粉，并为微杆菌提供稳定的栖息地。
