生物磁性纳米材料——磁小体培养优化及形成过程研究  

OBSERVATION OF THE ASSEMBLING PROCESS OF MAGNETOSOME AND OPTIMIZATION OF THE CULTURING CONDITIONS

作　　者：张宇红[1,2] 武洪庆[1,3] 肖天[1] 

机构地区：[1]中国科学院海洋研究所海洋生态与环境科学重点实验室,青岛266071 [2]辽宁省环境科学研究院辽宁省流域污染控制重点实验室,沈阳110031 [3]河北工业大学化工学院,天津300130

出　　处：《海洋与湖沼》2010年第4期597-605,共9页Oceanologia Et Limnologia Sinica

基　　金：人类前沿科学研究计划;HFSPRGP0035/2004-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

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1.166×109cells/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。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,1.166×109cells/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.

关 键 词：趋磁细菌 磁小体 优化培养 功能材料 

分 类 号：Q93[生物学—微生物学]