Decoding astrocyte heterogeneity: New tools for clonal analysis.

The importance of astrocyte heterogeneity came out as a hot topic in neurosciences especially over the last decades, when the development of new methodologies allowed demonstrating the existence of big differences in morphological, neurochemical and physiological features between astrocytes. However, although the knowledge about the biology of astrocytes is increasing rapidly, an important characteristic that remained unexplored, until the last years, has been the relationship between astrocyte lineages and cell heterogeneity. To fill this gap, a new method called StarTrack was recently developed, a powerful genetic tool that allows tracking astrocyte lineages forming cell clones. Using StarTrack, a single astrocyte progenitor and its progeny can be specifically labeled from its generation, during embryonic development, to its final fate in the adult brain. Because of this specific labeling, astrocyte clones, exhibiting heterogeneous morphologies and features, can be easily analyzed in relation to their ontogenetic origin. This review summarizes how astrocyte heterogeneity can be decoded studying the embryonic development of astrocyte lineages and their clonal relationship. Finally, we discuss about some of the challenges and opportunities emerging in this exciting area of investigation.

Reference-frame-independent quantum-key-distribution server with a telecom tether for an on-chip client.

We demonstrate a client-server quantum key distribution (QKD) scheme. Large resources such as laser and detectors are situated at the server side, which is accessible via telecom fiber to a client requiring only an on-chip polarization rotator, which may be integrated into a handheld device. The detrimental effects of unstable fiber birefringence are overcome by employing the reference-frame-independent QKD protocol for polarization qubits in polarization maintaining fiber, where standard QKD protocols fail, as we show for comparison. This opens the way for quantum enhanced secure communications between companies and members of the general public equipped with handheld mobile devices, via telecom-fiber tethering.

Peripheral contributions to olfactory bulb cell populations (migrations towards the olfactory bulb).

The olfactory system represents one of the most suitable models to study interactions between the peripheral and central nervous systems. The developing olfactory epithelium (olfactory placode and pit) gives rise to several cell populations that migrate towards the telencephalic vesicle. One of these cell populations, called the Migratory Mass (MM), accompanies the first emerging olfactory axons from the olfactory placode, but the fate of these cells and their contribution to the Olfactory Bulb (OB) populations has not been properly addressed. To asses this issue we performed ultrasound-guided in utero retroviral injections at embryonic day (E) 11 revealing the MM as an early source of Olfactory Ensheathing Cells in later postnatal stages. Employing a wide number of antibodies to identify the nature of the infected cells we described that those cells generated within the MM at E11 belong to different cell populations both in the mesenchyma, where they envelop olfactory axons and express the most common glial markers, and in the olfactory bulb, where they are restricted to the Olfactory Nerve and Glomerular layers. Thus, the data reveal the existence of a novel progenitor class within the MM, potentially derived from the olfactory placode which gives rise to different neural cell population including some CNS neurons, glia and olfactory ensheathing cells.