70 research outputs found

    Phospholipase C is required for glucose-induced calcium influx in budding yeast

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    AbstractIntracellular calcium is a second messenger involved in several processes in yeast, such as mating, nutrient sensing, stress response and cell cycle events. It was reported that glucose addition stimulates a rapid increase in free calcium level in yeast. To investigate the calcium level variations induced by different stimuli we used a reporter system based on the photoprotein aequorin. Glucose addition (50 mM) to nutrient-starved cells induced an increase in free intracellular calcium concentration, mainly due to an influx from external medium. The increase of calcium reached its maximum 100–120 s after the stimulus. A concentration of about 20 mM glucose was required for a 50% increase in intracellular calcium. This response was completely abolished in strain plc1Δ and in the isogenic wild-type strain treated with 3-nitrocoumarin, a phosphatidylinositol-specific phospholipase C inhibitor, suggesting that Plc1p is essential for glucose-induced calcium increase. This suggests that Plc1p should have a significant role in transducing glucose signal. The calcium influx induced by addition of high glucose on cells previously stimulated with low glucose levels was inhibited in strains with a deletion in the GPR1 or GPA2 genes, which suggests that glucose would be detected through the Gpr1p/Gpa2p receptor/G protein-coupled (GPCR) complex. Moreover, the signal was completely abolished in a strain unable to phosphorylate glucose, which is consistent with the reported requirement of glucose phosphorylation for GPCR complex activation

    Organic and inorganic mineral sources for weanling piglets

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    A presente pesquisa foi realizada com o objetivo de comparar os efeitos de fontes orgânicas e inorgânicas de microminerais sobre o desempenho, os parâmetros sanguíneos e a deposição de minerais em tecidos e órgãos de leitões desmamados. Foram utilizados 54 leitões de genética comercial, desmamados com idade média de 24 dias e peso médio de 7,35±0,88kg, num delineamento experimental de blocos ao acaso, com dois tratamentos, nove repetições e três animais por parcela. Os tratamentos foram representados pelo uso de rações suplementadas com minerais de fontes orgânicas ou inorgânicas (Cu, Zn, Fe, Mn e Se) no período dos 24 aos 57 dias de idade. Foram avaliados o consumo diário de ração, o ganho diário de peso, a conversão alimentar, os parâmetros hematológicos e a deposição de minerais em tecidos e órgãos. As fontes orgânicas de minerais nas rações fornecidas dos 24 aos 57 dias de idade melhoraram o ganho diário de peso (P=0,06) e a conversão alimentar (P=0,05) e aumentaram o número de hemáceas (P=0,10), contudo não influenciaram a deposição de minerais no músculo masseter, fígado, coração, baço e rim. Portanto, o suplemento de minerais de fontes orgânicas foi mais eficiente para o desempenho dos leitões na fase de creche.This research was conducted in order to compare the effects of organic and inorganic sources of mineral sources on performance, blood parameters and deposition of minerals in tissues and organs of nursery piglets. This experiment used 54 piglets from a commercial line, which were weaned at the mean age of 24 days and mean weight of 7.35±0,88kg, in a randomized block design with two treatments, nine replicates and three animals per replicate. The treatments consisted of rations supplemented with either organic or inorganic mineral sources (Cu, Zn, Fe, Mn and Se) during the 24 to 57 days old. It was evaluated daily feed intake, daily weight gain, gain ratio, hematological parameters, mineral deposition in tissues and organs. The organic mineral sources fed from 24 to 57 days of age improved daily weight gain (P=0.06) and feed: gain ratio (P=0.05) and also raised red blood cell count (P=0.10); however, no effect was found on mineral deposition in the masseter muscle, liver, heart, spleen or kidneys. Therefore, organics minerals sources increased performance of nursery piglets

    Voltage-gated Na<sup>+</sup> channel activity increases colon cancertranscriptional activity and invasion via persistent MAPK signaling

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    © 2015 Macmillan Publishers Limited. All rights reserved. Functional expression of voltage-gated Na+ channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using pharmacological inhibitors/activators and siRNA-mediated gene knockdowns, we correlated channel activity with Rap1-dependent persistent MAPK activation in the SW620 human colon cancer cell line. We further demonstrated that VGSC activity induces downstream changes in invasion-related gene expression via a PKA/ERK/c-JUN/ELK-1/ETS-1 transcriptional pathway. This is the first study illustrating a molecular mechanism linking functional activity of VGSCs to transcriptional activation of invasion-related genes

    Axon growth and guidance genes identify nascent, immature, and mature olfactory sensory neurons

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    Neurogenesis of projection neurons requires that axons be initiated, extended, and connected. Differences in the expression of axon growth and guidance genes must drive these events, but comprehensively characterizing these differences in a single neuronal type has not been accomplished. Guided by a catalog of gene expression in olfactory sensory neurons (OSNs), in situ hybridization and immunohistochemistry revealed that Cxcr4 and Dbn1 , two axon initiation genes, marked the developmental transition from basal progenitor cells to immature OSNs in the olfactory epithelium. The CXCR4 immunoreactivity of these nascent OSNs overlapped partially with markers of proliferation of basal progenitor cells and partially with immunoreactivity for GAP43, the canonical marker of immature OSNs. Intracellular guidance cue signaling transcripts Ablim1, Crmp1, Dypsl2, Dpysl3, Dpysl5, Gap43, Marcskl1, and Stmn1–4 were specific to, or much more abundant in, the immature OSN layer. Receptors that mediate axonal inhibition or repulsion tended to be expressed in both immature and mature OSNs ( Plxna1, Plxna4, Nrp2, Efna5 ) or specifically in mature OSNs ( Plxna3, Unc5b, Efna3, Epha5, Epha7 ), although some were specific to immature OSNs ( Plxnb1, Plxnb2, Plxdc2, Nrp1 ). Cell adhesion molecules were expressed either by both immature and mature OSNs ( Dscam, Ncam1, Ncam2, Nrxn1 ) or solely by immature OSNs ( Chl1, Nfasc1, Dscaml1 ). Given the loss of intracellular signaling protein expression, the continued expression of guidance cue receptors in mature OSNs is consistent with a change in the role of these receptors, perhaps to sending signals back to the cell body and nucleus. © 2010 Wiley‐Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106698/1/22497_ftp.pd
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