| 摘要: |
| 采用正交试验的方法优化磁小体培养条件, 结果使趋磁细菌 OD600 达到 0.440 (生物量为1.166×109 cells/ml), 同时运用磁收集传代法, 使趋磁细菌 Cmag 值稳定在 1.9—2.0。培养时用透射电镜观察磁小体形成过程, 结果发现培养 24h 细菌体内已有较小晶体形成且沿长轴分布; 48h 晶体长大且形成分段链沿长轴排列; 72h晶体进一步成熟仍以分段链沿长轴排列; 随后细菌逐渐衰亡磁小体变小, 168h 可见部分自溶细菌中仍有磁小体链; 192h 细菌自溶磁小体链分散到环境中。还观察到磁小体在细菌分裂时采用两种分离方式, 一种为磁小体分配到两个子细胞; 另一种为磁小体只分配到一个子细胞。无磁小体的子细胞, 一部分逐渐产生磁小体, 另一部分不产生磁小体。
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| 关键词: 趋磁细菌, 磁小体, 优化培养, 功能材料 |
| DOI：10.11693/hyhz201004020020 |
| 分类号: |
| 基金项目:人类前沿科学研究计划, HFSP RGP0035/2004-C号; 中国科学院海外杰出学者基金, 2006-1-15号; 国家自然科学基金项目资助, 40776094 号 |
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| OBSERVATION OF THE ASSEMBLING PROCESS OF MAGNETOSOME AND OPTIMIZATION OF THE CULTURING CONDITIONS |
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ZHANG Yu-Hong1,2, WU Hong-Qing1,3, XIAO Tian1
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1.Key Laboratory of Marine Ecology & Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences;2.Liaoning Province Key Laboratory of Basin Pollution Control, Liaoning Academy of Environmental Sciences;3.School of Chemical Engineering and Technology, Hebei University of Technology
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| Abstract: |
| Orthogonal experimental design was used to optimize growth conditions of magnetosome in Magnetospirillum magneticum AMB-1. Iron resource, volume, pH and temperature were chosen as influencing factors to optimize the growth condition of M. magneticum AMB-1. The optimal growth conditions were ferric quinine 0.02mmol/L, 75% occupation of the bioreactor, pH 6.7 and 25℃; and cells were harvested at OD600 0.44 (cell density, 1.166×109 cells/ml). Cmag value was used to characterize the magnetite in magnetotactic bacterial cells. M. magneticum AMB-1 cells were collected by magnet before inoculation. After magnetic enrichment and cultivation for ten generations, Cmag value was stabilized at 1.9—2.0. Magnetosome assembling was observed under Transmission Electron Microscope. Small crystals appeared after a 24-h cultivation. At 48h, crystals grew larger and assembled into chains along the long axis in subsections. At 72h, crystals matured and still arranged along the long axis in subsections. At 168h, crystals in liner magnetosome chains were observed in partly-autolyzed cells. At 192h, magnetic cells were fully autolyzed, and magnetosome chains were released to culture medium. Two magnetosome separation modes in dividing M. magneticum AMB-1 cells were observed. One was symmetric separation of magnetosome into daughter cells. The other was asymmetric separation, and only one daughter cell was the heritor of magnetosome. Part of the non-magnetosome daughter cells could produce magnetosome later, but part of non-magnetosome daughter cells might never produce magnetosome, even after they divided again.
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| Key words: Magnetotactic bacteria, Magnetosomes, Optimizing culturing, Functional Materials |
