Search results for "fer"

Aplidin® induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 ph…

2006

Aplidin® is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin® alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin® generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin® activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulatio…

Tiam1 as a Signaling Mediator of Nerve Growth Factor-Dependent Neurite Outgrowth

2010

Nerve Growth Factor (NGF)-induced neuronal differentiation requires the activation of members of the Rho family of small GTPases. However, the molecular mechanisms through which NGF regulates cytoskeletal changes and neurite outgrowth are not totally understood. In this work, we identify the Rac1-specific guanine exchange factor (GEF) Tiam1 as a novel mediator of NGF/TrkA-dependent neurite elongation. In particular, we report that knockdown of Tiam1 causes a significant reduction in Rac1 activity and neurite outgrowth induced by NGF. Physical interaction between Tiam1 and active Ras (Ras- GTP), but not tyrosine phosphorylation of Tiam1, plays a central role in Rac1 activation by NGF. In add…

Rac1 and PAK1 are upstream of IKK-ε and TBK-1 in the viral activation of interferon regulatory factor-3

2004

The anti-viral type I interferon (IFN) response is initiated by the immediate induction of IFN beta, which is mainly controlled by the IFN-regulatory factor-3 (IRF-3). The signaling pathways mediating viral IRF-3 activation are only poorly defined. We show that the Rho GTPase Rac1 is activated upon virus infection and controls IRF-3 phosphorylation and activity. Inhibition of Rac1 leads to reduced IFN beta promoter activity and to enhanced virus production. As a downstream mediator of Rac signaling towards IRF-3, we have identified the kinase p21-activated kinase (PAK1). Furthermore, both Rac1 and PAK1 regulate the recently described IRF-3 activators, I kappa B kinase- and TANK-binding kina…

Rho GTPases in human breast tumours: expression and mutation analyses and correlation with clinical parameters

2002

In the present study, we addressed the question of a putative relevance of Rho proteins in tumour progression by analysing their expression on protein and mRNA level in breast tumours. We show that the level of RhoA, RhoB, Rac1 and Cdc42 protein is largely enhanced in all tumour samples analysed (n=15) as compared to normal tissues originating from the same individual. The same is true for 32P-ADP-ribosylation of Rho proteins which is catalysed by Clostridium botulinum exoenzyme C3. Also the amount of Rho-GDI and ERK2 as well as the level of overall 32P-GTP binding acvitity was tumour-specific elevated, yet to a lower extent than Rho proteins. Although the amount of Rho proteins was enhance…

Modificētās L-ornitīna δ-aminotransferāzes strukturālie pētījumi jaunu diazonamīda A struktūranalogu dizainam

2015

Darba mērķi ir izstrādāt metodi rekombinantas modificētās ornitīna δ-aminotransferāzes (MOAT) produkcijai un kristalizēšanai, analizēt MOAT strukturālās atšķirības no ornitīna δ-aminotransferāzes (OAT), kā arī noteikt MOAT kristālu struktūru kompleksā ar Latvijas Organiskās sintēzes institūta pētnieku sintezētajiem diazonamīda A struktūranalogiem. Tādejādi, varētu noteikt MOAT un diazonamīda A struktūranalogu ķīmisko mijiedarbību veidu, iegūstot zināšanas jaunu MOAT inhibitoru dizainam. Bakalaura darba laikā tika iegūts rekombinants, E.coli producēts, MOAT, kā arī MOAT kristālstruktūra kompleksā ar piridoksāla 5´ fosfātu. Bakalaura darbs tika izstrādāts Latvijas Biomedicīnas pētījumu un stu…

Dažas racionālu diferenču vienādojumu problēmas

2015

Bakalaura darba mērķis ir izpētīt globālo raksturu noteiktam racionālam trešās kārtas diferenču vienādojumam ar konverģentiem koeficientiem {\beta_n} un {B_n} un ar patvaļīgiem nenegatīviem sākuma nosacījumiem x_{-2}; x_{-1}; x_0. Darbā ir aplūkoti daži racionāli trešās kārtas diferenču vienādojumi, to līdzsvara punktu stabilitāti, teorēmas un jēdzieni, kuri palīdz analizēt vienādojumu atrisinājumus. Bakalaura darbs ir papildināts ar vienādojumu atrisinājumu grafiskiem attēliem, kā arī ar formulu izvedumiem un teorēmu pierādījumu paplašinājumiem. Iegūtie rezultāti un secinājumi par noteiktu diferenču vienādojumu palīdz izprast tā atrisinājuma izturēšanos un līdzsvara punktu stabilitāti. Apr…

Incidence de la clarification des moûts de raisin sur les fermentescibilltés alcoolique et malolactique

1993

<p style="text-align: justify;">Des essais de débourbage en vinification en blanc, réalisés de 1988 à 1992, mettent en évidence le rôle important joué par la teneur en macromolécules solubles dans le moût de raisin. Les moûts de faible turbidité conduisent en effet à des fermentations alcooliques lentes en relation avec de faibles populations levuriennes. Il est également confirmé que la libération de polysaccharides exocellulaires par les levures au cours de la fermentation alcoolique est d'autant plus élevée que le moût de départ a été fortement appauvri en colloïdes de raisin. Par contre, ce sont dans les lots les plus clarifiés que l'on observe la meilleure fermentescibilité malol…

Nuove tecnologie radar per il monitoraggio delle deformazioni superficiali del terreno: casi di studio in Sicilia

2009

Radial symmetry of p-harmonic minimizers

2017

"It is still not known if the radial cavitating minimizers obtained by Ball [J.M. Ball, Discontinuous equilibrium solutions and cavitation in nonlinear elasticity, Phil. Trans. R. Soc. Lond. A 306 (1982) 557--611] (and subsequently by many others) are global minimizers of any physically reasonable nonlinearly elastic energy". The quotation is from [J. Sivaloganathan and S. J. Spector, Necessary conditions for a minimum at a radial cavitating singularity in nonlinear elasticity, Ann. Inst. H. Poincare Anal. Non Lineaire 25 (2008), no. 1, 201--213] and seems to be still accurate. The model case of the $p$-harmonic energy is considered here. We prove that the planar radial minimizers are indee…

Numerical treatment of radiation processes in the internal shocks of magnetized relativistic outflows

2017

Los blázares son un tipo de núcleo activo de galaxia (AGN, por sus siglas en inglés) que se encuentran entre los objetos astrofísicos más energéticos y violentos, a la par de los brotes de rayos gamma (GRB por sus siglas en inglés). Los procesos físicos y, en particular, el escenario del chorro relativista en el que se genera la radiación ultraenergética detectada por observatorios terrestres y en órbita, han conseguido atraer la atención e interés de los astrónomos y astrofísicos desde su descubrimiento. En la presente tesis investigamos el modelo de choques internos (IS) cuya hipótesis consta del choque de dos capas de plasma con geometría cilíndrica, formando dos ondas de choque que atra…