Age-related changes in cell proliferation and stem cell activity. Mitotic cells were labeled through administration of a single pulse of BrdU, followed by a survival time of 2 hours. To identify proliferating stem cells, double immunostaining against BrdU and Sox2 was performed. A-A”: Overview of the distribution of mitotic cells and/or stem cells in the molecular layer of the valvula cerebelli pars medialis, a proliferation zone displaying high mitotic activity in the brain of A. leptorhynchus. The majority of the BrdU-positive cells also express Sox2 (arrows), indicating that they are active stem cells. Note the abundance of cells undergoing mitosis and/or expressing Sox2 in this section, which was taken from the brain of one of the oldest fish used in the present study. Scale bar = 40 μm. B: High-magnification confocal image illustrating actively proliferating (arrows) and quiescent (arrowheads) Sox2-positive stem cells. Scale bar = 5 μm. C-C’: Total and relative numbers of BrdU-labeled cells in the whole brain, as a function of total length of the fish. D-D’: Total and relative numbers of BrdU/Sox2 double-labeled cells in the whole brain, as a function of total length. Closed lines indicate linear regression fits. Dashed lines represent the 90% confidence bounds of these fits. The red dotted lines indicate 2.5-fold decreases over the examined range. (From Traniello et al., 2014.)


Traniello, I.M.*, Sîrbulescu, R.F.*, Ilieş, I.*, Zupanc, G.K.H.: Age-related changes in stem cell dynamics, neurogenesis, apoptosis, and gliosis in the adult brain: A novel teleost fish model of negligible senescence. Developmental Neurobiology 74, 514-530 (2014), doi:10.1002/dneu.22145 (* equal contributions)

Ilieş, I.*, Traniello, I.M.*, Sîrbulescu, R.F.*, Zupanc, G.K.H.: Determination of relative age using growth increments of scales as a minimally invasive method in the tropical freshwater Apteronotus leptorhynchus. Journal of Fish Biology 84, 1312-1325 (2014), doi:10.1111/jfb.12354 (* equal contributions)

Ilieş, I.*, Sîrbulescu, R.F.*, Zupanc, G.K.H.: Indeterminate body growth and lack of gonadal decline in the brown ghost knifefish (Apteronotus leptorhynchus), an organism exhibiting negligible brain senescence. Canadian Journal of Zoology 92, 947-953 (2014), doi:10.1139/cjz-2014-0109 (* equal contributions)