The nerves were found to linearly increase in length at an average rate of

9.24 mu m h(-1) over the 96 h period of larval life. Further, mitochondrial density increases over this period at an average rate of 4.49 x 10(-3) (mitochondria mu m(-1))h(-1). Mitochondria in the nerves had a half-life CAL 101 of 35.2 h. To account for the distribution of the mitochondria we observe, we derived a mathematical model which suggests that cellular production of mitochondria increases quadratically over time and that a homeostatic mechanism maintains a constant density of mitochondria along the nerve. These data suggest a complex relationship between axonal length and mass production and that the neuron may have an “”axonal length sensor.”" (C) 2008 Elsevier Ltd. All rights reserved.”
“The adult newt retinal regeneration is an ideal model for studying retinal regeneration by transdifferentiation of the retinal pigment epithelium (RPE) cells. Accumulated BMS-777607 molecular weight evidence suggests that the RNA-binding protein Musashi-1 (Msi1) is expressed in mature photoreceptors and RPE cells as well as in retinal stem/progenitor cells, being essential for vision.

We have been investigating whether Msi1 is also essential for retinal regeneration. In the last paper [K. Susaki.J. Kaneko.Y. Yamano, K. Nakamura, W. Inami.T. Yoshikawa, Y. Ozawa, S. Shibata, O. Matsuzaki, H. Okano, C. Chiba, Musashi-1, an RNA-binding protein, is indispensable for survival of photoreceptors. Exp. Eye Res. (in press)], we showed that the expression profiles of Msi1 transcripts and protein isoforms change during retinal

regeneration. In the current report, we show by immunohistochemistry that Msi1 is expressed in transdifferentiating cells or cells of regenerating retinal tissues. Upon retinectomy, Msi1 protein, which is expressed in the nuclei of intact (stage E-0) RPE cells, changed its subcellular localization, being expressed in both the nucleus and cytoplasm of the RPE-derived stern-like Cell Penetrating Peptide cells at stage E-1. As the retinal rudiment/regenerating retina (rR) and renewing RPE (rRPE) are specified from the stem-like cell population (stage E-2). Msi1 expression was maintained or up-regulated in the rR. while clown-regulated in the rRPE. During further retinal regeneration, Msi1 expression was decreased in association with cell differentiation, except for photoreceptors and RPE cells whose Msi1 expression increased as they differentiate. Thus, Msi1 is likely to be regulated at various cellular events during retinal regeneration, implying that Msi1 may have multi-functions in retinal regeneration. All together, it is probable that Msi1 is one of the essential factors that need to be regulated in retinal regeneration. (C) 2008 Elsevier Ireland Ltd. All rights reserved.