SPECTROSCOPY, IMAGING, OTHER TECHNIQUES |
Subcellular in vivo 1H MR spectroscopy of Xenopus laevis oocytes
Seung-Cheol Lee 1, Jee-Hyun Cho 1, Daniel Mietchen 2, Young-Sook Kim 1, Kwan Soo Hong 1, Chulhyun Lee 1, Dongmin Kang 1, Ki Deok Park 1, Byong-Seok Choi 3 and Chaejoon Cheong 1*
1 Korea Basic Science Institute
2 Fraunhofer Institute for Biomedical Engineering
3 KAIST
* To whom correspondence should be addressed. E-mail: cheong{at}kbsi.re.kr.
Submitted on September 1, 2005
Revised on October 12, 2005
Accepted on 16 November 2005
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Abstract |
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In vivo magnetic resonance (MR) spectra are typically obtained from voxels whose spatial dimensions far exceed those of the cells they contain. This study was designed to evaluate the potential of localized MR spectroscopy to investigate subcellular phenomena. Using a high magnetic field and a home-built microscopy probe with large gradient field strengths, we achieved voxel sizes of (180 µm)3. In the large oocytes of the frog Xenopus laevis, this was small enough to allow the recording of the first compartment-selective in vivo MR spectra from the animal and vegetal cytoplasm as well as the nucleus. The two cytoplasmic regions differed in their lipid contents and NMR lineshape characteristics - differences that are not detectable with whole-cell NMR techniques. In the nucleus, the signal appeared to be dominated by water, whereas other contributions were negligible. We also used localized spectroscopy to monitor the uptake of diminazene acturate, an anti-trypanosomal agent, into compartments of a single living oocyte. The resulting spectra from the nucleus and cytoplasm revealed different uptake kinetics for the two components of the drug and demonstrate that MR technology is on the verge of becoming a tool for cell biology.
Key Words:
Xenopus laevis, cell compartments, drug uptake, magnetic resonance, single cell
