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 to 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.
@article{arxiv.1609.02642,
title = {X-ray microtomographic visualization of Escherichia coli by metalloprotein overexpression},
author = {Ryuta Mizutani and Keisuke Taguchi and Masato Ohtsuka and Minoru Kimura and Akihisa Takeuchi and Kentaro Uesugi and Yoshio Suzuki},
journal= {arXiv preprint arXiv:1609.02642},
year = {2016}
}