Search results for "Porte"

Violence scolaire en rapport avec supporteurs de football à Bogota

2013

El propósito de este estudio es caracterizar una de las formas de violencia escolar asociada al fenómeno de las barras del fútbol. Este ha venido tomando fuerza en Colombia, especialmente en Bogotá y las grandes ciudades del país. Así lo evidencian diversos hechos sucedidos en los últimos años, relacionados con la participación de jóvenes hinchas de equipos de fútbol. La aplicación de tipo cualitativo, se llevó a cabo en cinco colegios oficiales de las localidades de Usaquén, Santa fe, Usme, Fontibón y Suba, en Bogotá, con 68 jóvenes escolarizados, a través del modelo de los núcleos de educación social –NES- basados en la Investigación Acción –IA- que involucra a los miembros de la comunida…

Droit et gouvernance:l'apport du courant comportemental

2010

Under the dominant approach to corporate governance, the role of law is to help reduce the impact of conflicts of interest and intentional strategic behavior of the different actors, including managers. The managers' decisions that are detrimental to shareholders and other stakeholders do not all have their origin in an intentional behavior. Some of them result of misjudgment, cognitive and behavioral biases. Based on Behavioral Law and Economics, which has expanded greatly in the United States, the objective of the paper is to show that the role of law within the corporate governance system is also to contribute to "debias" managerial decisions or correct any adverse effects of these biase…

The L-tartrate/succinate antiporter TtdT (YgjE) of L-tartrate fermentation in Escherichia coli.

2007

ABSTRACT Escherichia coli ferments l -tartrate under anaerobic conditions in the presence of an additional electron donor to succinate. The carrier for l -tartrate uptake and succinate export and its relation to the general C 4 -dicarboxylate carriers DcuA, DcuB, and DcuC were studied. The secondary carrier TtdT, encoded by the ttdT (previously called ygjE ) gene, is required for the uptake of l -tartrate. The ttdT gene is located downstream of the ttdA and ttdB genes, encoding the l -tartrate dehydratase TtdAB. Analysis of mRNA by reverse transcription-PCR showed that ttdA , ttdB , and ttdT are cotranscribed. Deletion of ttdT abolished growth by l -tartrate and degradation of l -tartrate c…

Down-regulation of the MHC class I antigen-processing machinery after oncogenic transformation of murine fibroblasts

1998

Malignant transformation is often associated with genetic alterations providing tumor cells with mechanisms for escape from immune surveillance. Human and murine tumors of various origin as well as in vitro models of viral and oncogenic transformation express reduced levels of major histocompatibility complex (MHC) class I antigens resulting in decreased sensitivity to MHC class I-restricted cytotoxic T lymphocyte (CTL)-mediated lysis. We here investigate whether the suppressed MHC class I surface expression of ras-transformed fibroblasts is due to dysregulation of the genes of the antigen-processing machinery, the peptide transporters TAP-1 and TAP-2 and the proteasome subunits LMP-2 and L…

Activity of Drug Efflux Transporters in Tumor Cells Under Hypoxic Conditions

2008

Tumor cells exhibit mechanisms by which chemotherapeutic drugs can be actively pumped out of the cell (e.g., p-glycoprotein pGP, MRP1), resulting in a multidrug resistant phenotype. Many human tumors show pronounced hypoxia which can result in a local ATP depletion which in turn may compromise the efficacy of these transporters. The aim of this study was therefore to assess the transport activity and expression of drug transporters under hypoxic conditions. Prostate carcinoma cells (R3327-AT1) were exposed to hypoxia (pO2≶0.5 mmHg) for up to 24h and pump activity was determined by an efflux assay. The results showed that exposing cells to hypoxia for 3–6 h led to a moderate increase in pGP …

Screening for Solute Transporters in Plant Photosynthetic Membranes

2008

As compared to chloroplast envelope transporters, the field of thylakoid transporters is largely unexplored. There is evidence for several transport activities in the plant thylakoid membrane, but only a copper P-type ATPase and an ATP/ADP carrier have been so far identified at the gene level in Arabidopsis thaliana. Using in silico analyses, we have predicted the existence of approximately 15 thylakoid transporters, including phosphate transporters and cation channels. For experimental validation, we have used peptide- specific antibodies and functional analyses in heterologous system. These novel data are highly relevant to understand the transport network of the thylakoid membrane and it…

Dysfunction of Torr causes a Harlequin-type ichthyosis-like phenotype in Drosophila melanogaster

2019

AbstractPrevention of desiccation is a constant challenge for terrestrial organisms. Land insects have an extracellular coat, the cuticle, that plays a major role in protection against exaggerated water loss. Here, we report that the ABC transporter Torr - a human ABCA12 paralog - contributes to the waterproof barrier function of the cuticle in the fruit fly Drosophila melanogaster. We show that the reduction or elimination of Torr function provokes rapid desiccation. Torr is also involved in defining the inward barrier against xenobiotics penetration. Consistently, the amounts of cuticular hydrocarbons that are involved in cuticle impermeability decrease markedly when Torr activity is redu…

Coordinate downregulation of multiple MHC class I antigen processing genes in chemical-induced murine tumor cell lines of distinct origin

2000

In murine tumor cell lines, downregulation of MHC class I surface expression has been frequently detected, but the underlying molecular mechanisms of such deficiencies have not been defined. In this study, murine tumor cell lines of different histology derived from spontaneous or from chemical-induced tumors were analyzed for the expression of multiple components of the major histocompatibility complex (MHC) class I antigen-processing machinery (APM), including the peptide transporter TAP, the interferon (IFN)-gamma inducible proteasome subunits and several chaperones. The tumor cell lines analyzed demonstrated a heterogeneous expression pattern of various APM components. In comparison to c…

Intertissue Flow of Glutathione (GSH) as a Tumor Growth-promoting Mechanism

2011

B16 melanoma F10 (B16-F10) cells with high glutathione (GSH) content show high metastatic activity in vivo. An intertissue flow of GSH, where the liver is the main reservoir, can increase GSH content in metastatic cells and promote their growth. We have studied here possible tumor-derived molecular signals that could activate GSH release from hepatocytes. GSH efflux increases in hepatocytes isolated from mice bearing liver or lung metastases, thus suggesting a systemic mechanism. Fractionation of serum-free conditioned medium from cultured B16-F10 cells and monoclonal antibody-induced neutralization techniques facilitated identification of interleukin (IL)-6 as a tumor-derived molecule prom…

Behavioral genetics of suicidality in Bipolar Disorder: the interaction between SERT and CLOCK polymorphisms and early-life stress

Il suicidio è un problema di salute pubblica sottostimato, così come è un lutto almeno parzialmente prevenibile: ogni contributo alla conoscenza dei fattori di rischio ad esso associati possono aiutare lo sviluppo di interventi terapeutici efficaci rivolti a fasce vulnerabili della popolazione. Più del 90% delle persone che si suicidano, o provano a farlo, hanno una malattia psichiatrica diagnosticabile e circa il 60% di tutte le morti per suicidio si verificano nel contesto di un disturbo dell’umore, soprattutto di tipo bipolare. Il suicidio ha oltretutto alta familiarità: la suicidalità è ereditabile, indipendentemente dalla diagnosi associata. Lo stress è un fattore di rischio sia prossi…