Narrow Results

Since the cellular metabolism has not yet been fully elucidated, it is very useful to get the information of elemental distributions in a single cell. We applied a micro-PIXE camera to obtain a picture presented with density of an element in a cell. Our micro-PIXE camera is on the basis of PIXE analysis using micro ion beams with the spot size of less than 1 μ m and the samples can be analyzed in air, so the size and the state of samples are not limited. Here, we analyzed the spatial distributions of elements in a single cell of animal for a medical application. Bovine aortic endothelial cells(BAECs) were cultured in culture medium containing bromodeoxyuridine(BrdU) which is known to be used in the DNA synthesis. We could take the elemental maps of phosphorus, potassium and sulfur which present well a shape of cell and a position of nucleus in this cell. Moreover, we obtained the picture of Br, that is, BrdU. It was found that BrdU was locally concentrated in two or three regions in the nucleus.

To produce precise number of neurons and glial cells from neuroepithelial cells, the progeression and exit of the cell cycle should accurately be coordinated. In mammalian neuroepithelial cells, the molecular and cellular mechanisms coordinating the cell cycle progression and neuronal differentiation is yet unknown. Recently, we noticed that a certain cell cycle regulator protein localized in the basal endfeet of the mouse neuroepithelial cells. However, it is difficult to know in which cell cycle phase the protein localizes, because suitable cell cycle markers expressed at the endfeet of the neuroepithelial cells are missing. To address this issue, we performed sequential labeling of neuroepithelial cells by introducing EGFP-F cDNA into cultured mouse embryos using electroporation and short pulse labeling of S-phase cells by incorporating BrdU, and analyzed the cell cycle phase of EGFP-F labeled cells by using antibodies to BrdU and PH3 (a M-phase marker). We found that EGFP-F-labled cells were in S-phase to Gl-phase, but not in G2-phase to M-phase 6 hours after electroporation, and that both of the nucleus and the whole outline of neuroepithelial cell including bipolar processes were clearly visualized. These results suggest that our labeling strategy makes it possible to characterize the cell cycle of neuroepithelial cells, and therefore the cell cycle-dependent distribution of cytoplasmic proteins at the endfeet would be elucidated in the future.