Live Imaging at the Onset of Cortical Neurogenesis Reveals Differential Appearance of the Neuronal Phenotype in Apical versus Basal Progenitor Progeny

The neurons of the mammalian brain are generated by progenitors dividing either at the apical surface of the ventricular zone (neuroepithelial and radial glial cells, collectively referred to as apical progenitors) or at its basal side (basal progenitors, also called intermediate progenitors). For apical progenitors, the orientation of the cleavage plane relative to their apical-basal axis is thought to be of critical importance for the fate of the daughter cells. For basal progenitors, the relationship between cell polarity, cleavage plane orientation and the fate of daughter cells is unknown. Here, we have investigated these issues at the very onset of cortical neurogenesis. To directly observe the generation of neurons from apical and basal progenitors, we established a novel transgenic mouse line in which membrane GFP is expressed from the beta-III-tubulin promoter, an early pan-neuronal marker, and crossed this line with a previously described knock-in line in which nuclear GFP is expressed from the Tis21 promoter, a pan-neurogenic progenitor marker. Mitotic Tis21-positive basal progenitors nearly always divided symmetrically, generating two neurons, but, in contrast to symmetrically dividing apical progenitors, lacked apical-basal polarity and showed a nearly randomized cleavage plane orientation. Moreover, the appearance of beta-III-tubulin–driven GFP fluorescence in basal progenitor-derived neurons, in contrast to that in apical progenitor-derived neurons, was so rapid that it suggested the initiation of the neuronal phenotype already in the progenitor. Our observations imply that (i) the loss of apical-basal polarity restricts neuronal progenitors to the symmetric mode of cell division, and that (ii) basal progenitors initiate the expression of neuronal phenotype already before mitosis, in contrast to apical progenitors

Selective hydrogenation of cinnamaldehyde to cinnamyl alcohol on L-zeolite supported catalysts

The selective hydrogenation of cinnamaldehyde was studied on Al2O3 and L zeolites supported catalysts. The addition of Sn improves the selectivity to cinnamyl alcohol on Pt/Al2O3 catalysts while the reaction activity has a maximum at Sn/Pt atomic ratio of 0.5. It is interesting to find that Pt/L catalysts show both high activities and selectivities to carbonyl hydrogenated product cinnamyl alcohol. On Pt/RbL and Pt/SrL catalysts, the selectivities to cinnamyl alcohol are higher than 90% even with the cinnamaldehyde conversion of 95%. The effects of metal morphology, channel structures and basicities of L-zeolites are discussed

FPGA-based trigger system for the LUX dark matter experiment

LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be >99% efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since its full underground deployment in early 2013. This document is an overview of the systems capabilities, its inner workings, and its performance

The caudal ganglionic eminence is a source of distinct cortical and subcortical cell populations

During development, the mammalian ventral telencephalon is comprised of three major proliferative zones: the medial (MGE), lateral (LGE) and caudal (CGE) ganglionic eminences. Through gene expression studies, in vitro migration assays, genetic mutant analysis and in vivo fate mapping in mice, we found that the CGE is a progenitor region that is distinct from both the MGE and LGE. Notably, CGE cells showed a unique in vivo pattern of migration, and the CGE contributed cells to nuclei distinct from those populated by the MGE and LGE. Moreover, we report that the migratory fate of cells from the CGE is intrinsically determined by embryonic day 13.5 (E13.5). Together, these results provide the first insights into the development and fate of the CGE