Graduate School of Engineering, Tokai University, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan.
J Synchrotron Radiat. 2013 Jul;20(Pt 4):581-6. doi: 10.1107/S0909049513008467. Epub 2013 May 1.
This paper reports X-ray microtomographic visualization of the microorganism Escherichia coli overexpressing a metalloprotein ferritin. The three-dimensional distribution of linear absorption coefficients determined using a synchrotron radiation microtomograph with a simple projection geometry revealed that the X-ray absorption was homogeneously distributed, suggesting that every E. coli cell was labeled with the ferritin. The ferritin-expressing E. coli exhibited linear absorption coefficients comparable with those of phosphotungstic acid stained cells. The submicrometer structure of the ferritin-expressing E. coli cells was visualized by Zernike phase contrast using an imaging microtomograph equipped with a Fresnel zone plate. The obtained images revealed curved columnar or bunching oval structures corresponding to the E. coli cells. These results indicate that the metalloprotein overexpression facilitates X-ray visualization of three-dimensional cellular structures of biological objects.
本文报道了过度表达金属结合蛋白铁蛋白的微生物大肠杆菌的 X 射线显微断层成像。使用具有简单投影几何形状的同步辐射微断层扫描仪确定的线性吸收系数的三维分布表明，X 射线吸收是均匀分布的，这表明每个大肠杆菌细胞都被铁蛋白标记。表达铁蛋白的大肠杆菌表现出与磷钨酸染色细胞相当的线性吸收系数。通过使用配备菲涅耳带板的成像微断层扫描仪，使用泽尼克相衬技术对表达铁蛋白的大肠杆菌细胞的亚微米结构进行了可视化。获得的图像显示了与大肠杆菌细胞相对应的弯曲柱状或束状椭圆形结构。这些结果表明，金属蛋白的过表达有利于生物物体的三维细胞结构的 X 射线可视化。
