Calcineurin primes immature gonadotropin-releasing hormone-secreting neuroendocrine cells for migration

During development, many neurons display calcium- dependent migration, but the role of this messenger in regulating gene expression leading to this event has not yet been elucidated. Among the decoders of calcium signals is calcineurin, a Ca2 / calmodulin serine/threonine phosphatase that has been involved in both short-term and long-term cellular changes. By using immortalized GnRH-secreting neurons, we now show that, in vitro, Ca2 - dependent gene expression, proceeding via calcineurin and the transcription factor nuclear factor of activated T cells, is a key player controlling the chemomigratory potential of developing GnRH-secreting neurons. Furthermore, our data highlight the switch nature of this phosphatase, whose activation or inactivation guides cells to proceed from one genetic program to the nex

Global observational needs and resources for marine biodiversity

Otros autores: Best, B., Brandt, A., Goodwin, K., Iken, A., Marques, A., Miloslavich, P., Ostrowski, M., Turner, W., Achterberg, E., Barry, T., Bigatti, G., Henry, L.A., Ramiro-Sánchez, B., Durán, P., Morato, T., Murray Roberts, J., García-Alegre, A., Cuadrado, M., Murton, B.The diversity of life in the sea is critical to the health of ocean ecosystems that support living resources and therefore essential to the economic, nutritional, recreational, and health needs of billions of people. Yet there is evidence that the biodiversity of many marine habitats is being altered in response to a changing climate and human activity. Understanding this change, and forecasting where changes are likely to occur, requires monitoring of organism diversity, distribution, abundance, and health. It requires a minimum of measurements including productivity and ecosystem function, species composition, allelic diversity, and genetic expression. These observations need to be complemented with metrics of environmental change and socio-economic drivers. However, existing global ocean observing infrastructure and programs often do not explicitly consider observations of marine biodiversity and associated processes. Much effort has focused on physical, chemical and some biogeochemical measurements. Broad partnerships, shared approaches, and best practices are now being organized to implement an integrated observing system that serves information to resource managers and decision-makers, scientists and educators, from local to global scales. This integrated observing system of ocean life is now possible due to recent developments among satellite, airborne, and in situ sensors in conjunction with increases in information system capability and capacity, along with an improved understanding of marine processes represented in new physical, biogeochemical, and biological models

Activation of excitatory amino acid receptors increases intracellular free [3H]arachidonate levels in cultured cerebellar neurons

[No abstract available

PHORBOL ESTERS ATTENUATE GLUTAMATE-STIMULATED INOSITOL PHOSPHOLIPID HYDROLYSIS IN NEURONAL CULTURES

The phorbol diesters 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-dibutyrate, but not 4-α-phorbol-didecanoate, inhibited the stimulation of inositol phospholipid hydrolysis by excitatory amino acids and carbamylcholine in primary cultures of cerebellar neurons. This inhibition was mimicked by the synthetic diacylglycerol 1,2-dioleoyl-rac-glycerol (DOG) and was selective for a specific glutamate-phosphoinositide receptor subtype (GP2 receptor) activated by glutamate and quisqualate. TPA was nearly inactive in inhibiting the stimulation of inositol phospholipid hydrolysis by N-methyl-D-aspartate, a selective agonist of the GP1 receptor. Phorbol diesters and DOG attenuated the stimulation of inositol phospholipid hydrolysis by glutamate and quisqualate also in cerebellar slices from 9-15-day-old rats; however, using this preparation, their action was weak and required high concentrations (>1 μM). The inhibition of signal transduction by phorbol diesters was not consequent to a reduced binding of glutamate to its membrane recognition sites. In fact, TPA induced only a small increase in the K(D) but not change in the B(max) of [3H]glutamate binding in cerebellar membranes. Phorbol diesters may act to inhibit specific GTP-binding proteins or particular forms of phosphoinositidase C associated with GP2 or muscarinic cholinergic receptors