Mechanisms and regulation of monosaccharide transport in suspension cultured cells of Vitis Vinifera

Apresentação efectuada no "14th Congress of the Federation of European Societies of Plant Biology", em Cracow, Polland em 2004.Fundação para a Ciência e a Tecnologia (FCT) - grant SFRH/BD/10689/2002

Utilization and transport of mannitol in Olea europaea and their implications on salt stress tolerance

Comunicação em painel no congresso "14th Congress of the Federation of European Societies of Plant Biology". August 23-27. 2004. Cracow. Poland.Fundação para a Ciência e a Tecnologia (FCT

Tumor necrosis factor-alpha modulates survival, proliferation, and neuronal differentiation in neonatal subventricular zone cell cultures

Tumor necrosis factor (TNF)- has been reported to modulate brain injury, but remarkably, little is known about its effects on neurogenesis. We report that TNF- strongly influences survival, proliferation, and neuronal differentiation in cultured subventricular zone (SVZ) neural stem/progenitor cells derived from the neonatal P1-3 C57BL/6 mice. By using single-cell calcium imaging, we developed a method, based on cellular response to KCl and/or histamine, that allows the functional evaluation of neuronal differentiation. Exposure of SVZ cultures to 1 and 10 ng/ml mouse or 1 ng/ml human recombinant TNF- resulted in increased differentiation of cells displaying a neuronal-like profile of [Ca2+]i responses, compared with the predominant profile of immature cells observed in control, nontreated cultures. Moreover, by using neutralizing antibodies for each TNF- receptor, we found that the proneurogenic effect of 1 ng/ml TNF- is mediated via tumor necrosis factor receptor 1 activation. Accordingly, the percentage of neuronal nuclear protein-positive neurons was increased following exposure to mouse TNF-. Interestingly, exposure of SVZ cultures to 1 ng/ml TNF- induced cell proliferation, whereas 10 and 100 ng/ml TNF- induced apoptotic cell death. Moreover, we found that exposure of SVZ cells to TNF- for 15 minutes or 6 hours caused an increase in the phospho-stress-activated protein kinase/c-Jun N-terminal kinase immunoreactivity initially in the nucleus and then in growing axons, colocalizing with tau, consistent with axonogenesis. Taken together, these results show that TNF- induces neurogenesis in neonatal SVZ cell cultures of mice. TNF-, a proinflammatory cytokine and a proneurogenic factor, may play a central role in promoting neurogenesis and brain repair in response to brain injury and infectio

Biochemical changes throughout grape berry development and fruit and wine quality

Wine is made up of more than one thousand compounds, the majority of which, such as vitamins and minerals, come from the grapes, while others, like ethanol and glycerol, are products of the winemaking process. Although sugars are either partially or completely transformed, sugar import and accumulation into the ripening berry is a major parameter of wine quality. Sugar status is directly related to the final alcoholic content of wine, and regulates several genes responsible for the development of its aromatic and organoleptic properties. Physiological ripeness is reached when the grapes achieve sufficiently high sugar levels without loosing too much acidity; however, aromatic and phenolic compound content must also be taken into account. Softening and water content are other essential characteristics of a ripe berry. From a winemaker point of view, optimal grape maturity is essential for wine quality, but is difficult to assess because it is under multifactorial control, involving grapevine cultivar variety and environmental parameters such as soil, temperature, exposure to sun, and hormonal regulation. Continued study of the key control points in grape ripening is crucial if we ultimately hope to improve grape and wine quality.Fundação para a Ciência e a Tecnologia (FCT)(research project ref. POCI/AGR/56378/2004; to C.C., grant ref. SFRH/BD/10689/2002, to P.S. grant ref. SFRH/BD/13460/2003, to N.F. grant ref. SFRH/BD/23169/2005, and to A.A., grant ref. SFRH/PBD/17166/2004

Activation of Type 1 Cannabinoid Receptor (CB1R) promotes neurogenesis in murine subventricular zone cell cultures

The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+](i)) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.Fundacao para a Ciencia e a Tecnologia - Portugal [POCTI/SAU-NEU/68465/2006, PTDC/SAU-NEU/104415/2008, PTDC/SAU-NEU/101783/2008, POCTI/SAU-NEU/110838/2009]; Fundacao Calouste Gulbenkian [96542]; Fundacao para a Ciencia e Tecnologiainfo:eu-repo/semantics/publishedVersio

Mannitol transport and mannitol dehydrogenase activities are coordinated in olea europaea under salt and osmotic stresses

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Plant and Cell Physiology following peer review. The definitive publisher-authenticated version is available online at http://pcp.oxfordjournals.org/cgi/content/abstract/pcr121? ijkey=6orgUM5fkIjedYn&keytype=refThe intracellular accumulation of organic compatible solutes functioning as osmoprotectants, such as polyols, is an important response mechanism of several plants to drought and salinity. In Olea europaea a mannitol transport system (OeMaT1) was previously characterised as a key player in plant response to salinity. In the present study, heterotrophic sink models, such as olive cell suspensions and fruit tissues, and source leaves were used for analytical, biochemical and molecular studies. The kinetic parameters of mannitol dehydrogenase (MTD) determined in mannitol-growing cells, at 25 °C and pH 9.0, were as follows: Km, 54.5 mM mannitol and Vmax, 0.47 μmol h-1 mg-1 protein. The corresponding cDNA was cloned and named OeMTD1. OeMTD1 expression was correlated with MTD activity, OeMaT1 expression and carrier-mediated mannitol transport, in mannitol- and sucrose-growing cells. Furthermore, sucrosegrowing cells displayed only residual OeMTD activity, even though high levels of OeMTD1 transcription were observed. There is evidence OeMTD is regulated at both transcriptional and post-transcriptional levels. MTD activity and OeMTD1 expression were repressed after Na+, K+ and PEG treatments, both in mannitol- and sucrose-growing cells. In contrast, salt and drought significantly increased mannitol transport activity and OeMaT1 expression. Altogether, these studies support that olive tree copes with salinity and drought by coordinating mannitol transport with intracellular metabolism.This work was supported by the Portuguese Foundation for Science and Technology (FCT) (research project ref. PTDC/AGR-ALI/100636/2008; to A. Conde, grant ref. SFRH/BD/47699/2008; to C. Conde, grant ref. SFRH/BPD/34998/2007; to P. Silvagrant ref. SFRH/BD/13460/2003)

N,N′-Dimethyl­ethylenediammonium dioxalatocuprate(II)

The asymmetric unit of the title salt, (C4H14N2)[Cu(C2O4)2], consists of one complex anion and two cationic half-mol­ecules, the other halves being generated by inversion symmetry. The CuII atom in the anion is coordinated by two bidentate oxalate ligands in a distorted square-planar geometry. Inter­molecular hydrogen bonds, involving the NH groups as donors and O atoms as acceptors, are observed, which lead to the formation of a three-dimensional network structure