Expression analysis of the AtPHO1 gene family in Arabidopsis thaliana and the involvement of AtPHO1 in the regulation of stomatal movements

Résumé Le transfert du phosphate des racines vers les feuilles s'effectue par la voie du xylème. Il a été précédemment démontré que la protéine AtPHO1 était indispensable au transfert du phosphate dans les vaisseaux du xylème des racines chez la plante modèle Arabidopsis thaliana. Le séquençage et l'annotation du génome d'Arabidopsis ont permis d'identifier dix séquences présentant un niveau de similarité significatif avec le gène AtPHO1 et constituant une nouvelle famille de gène appelé la famille de AtPHO1. Basée sur une étude moléculaire et génétique, cette thèse apporte des éléments de réponse pour déterminer le rôle des membres de ia famille de AtPHO1 chez Arabidopsis, inconnue à ce jour. Dans un premier temps, une analyse bioinformatique des séquences protéiques des membres de la famille de AtPHO1 a révélé la présence dans leur région N-terminale d'un domaine nommé SPX. Ce dernier est conservé parmi de nombreuses protéines impliquées dans l'homéostasie du phosphate chez la levure, renforçant ainsi l'hypothèse que les membres de la famille de AtPHO1 auraient comme AtPHO1 un rôle dans l'équilibre du phosphate dans la plante. En parallèle, la localisation tissulaire de l'expression des gènes AtPHO dans Arabidopsis a été identifiée par l'analyse de plantes transgéniques exprimant le gène rapporteur uidA sous le contrôle des promoteurs respectifs des gènes AtPHO. Un profil d'expression de chaque gène AtPHO au cours du développement de la plante a été obtenu. Une expression prédominante au niveau des tissus vasculaires des racines, des feuilles, des tiges et des fleurs a été observée, suggérant que les gènes AtPHO pourraient avoir des fonctions redondantes au niveau du transfert de phosphate dans le cylindre vasculaire de ces différents organes. Toutefois, plusieurs régions promotrices des gènes AtPHO contrôlent également un profil d'expression GUS non-vasculaire, indiquant un rôle putatif des gènes AtPHO dans l'acquisition ou le recyclage de phosphate dans la plante. Dans un deuxième temps, l'analyse de l'expression des gènes AtPHO durant une carence en phosphate a établi que seule l'expression des gènes AtPHO1, AtPHO1; H1 et AtPHO1; H10 est régulée par cette carence. Une étude approfondie de leur expression en réponse à des traitements affectant l'homéostasie du phosphate dans la plante a ensuite démontré leur régulation par différentes voies de signalisation. Ensuite, une analyse détaillée de la régulation de l'expression du gène AtPHO1; H1O dans des feuilles d'Arabidopsis blessées ou déshydratées a révélé que ce gène constitue le premìer gène marqueur d'une nouvelle voie de signalisation induite par l'OPDA, pas par le JA et dépendante de la protéine COI1. Ces résultats démontrent pour la première fois que l'OPDA et le JA peuvent activer différents gènes via des voies de signalisation dépendantes de COI1. Enfin, cette thèse révèle l'identification d'un nouveau rôle de la protéine AtPHO1 dans la régulation de l'action de l'ABA au cours des processus de fermeture stomatique et de germination des graines chez Arabidopsis. Bien que les fonctions exactes des protéines AtPHO restent à être déterminées, ce travail de thèse suggère leur implication dans la propagation de différents signaux dans la plante via la modulation du potentiel membranaire et/ou l'affectation de la composition en ions des cellules comme le font de nombreux transporteurs ou régulateur du transport d'ions. Summary Phosphate is transferred from the roots to the shoot via the xylem. The requirement for AtPHO1 protein to transfer phosphate to the xylem vessels of the root has been previously demonstrated in Arabidopsis thaliana. The sequencing and the annotation of the Arabidopsis genome had allowed the identification of ten sequences that show a significant level of similarity with the AtPHO1 gene. These 10 genes, of unknown functions, constitute a new gene family called the AtPHO1 gene family. Based on a molecular and genetics study, this thesis reveals some information needed to understand the role of the AtPHO1 family members in the plant Arabidopsis. First, a bioinformatics study revealed that the AtPHO sequences contained, in the N-terminal hydrophilic region, a motif called SPX and conserved among multiple proteins involved in phosphate homeostasis in yeast. This finding reinforces the hypothesis that all AtPHO1 family members have, as AtPHO1, a role in phosphate homeostasis. In parallel, we identified the pattern of expression of AtPHO genes in Arabidopsis via analysis of transgenic plants expressing the uidA reporter gene under the control of respective AtPHO promoter regions. The results exhibit a predominant expression of AtPHO genes in vascular tissues of all organs of the plant, implying that these AtPHO genes could have redundant functions in the transfer of phosphate to the vascular cylinder of various organs. The GUS expression pattern for several AtPHO promoter regions was also detected in non-vascular tissue indicating a broad role of AtPHO genes in the acquisition or in the recycling of phosphate in the plant. In a second step, the analysis of the expression of AtPHO genes during phosphate starvation established that only the expression of the AtPHO1, AtPHO1; H1 and AtPHO1; H10 genes were regulated by Pi starvation. Interestingly, different signalling pathways appeared to regulate these three genes during various treatments affecting Pi homeostasis in the plant. The third chapter presents a detailed analysis of the signalling pathways regulating the expression of the AtPHO1; H10 gene in Arabidopsis leaves during wound and dehydrated stresses. Surprisingly, the expression of AtPHO1; H10 was found to be regulated by OPDA (the precursor of JA) but not by JA itself and via the COI1 protein (the central regulator of the JA signalling pathway). These results demonstrated for the first time that OPDA and JA could activate distinct genes via COI1-dependent pathways. Finally, this thesis presents the identification of a novel role of the AtPHO1 protein in the regulation of ABA action in Arabidopsis guard cells and during seed germination. Although the exact role and function of AtPHO1 still need to be determined, these last findings suggest that AtPHO1 and by extension other AtPHO proteins could mediate the propagation of various signals in the plant by modulating the membrane potential and/or by affecting cellular ion composition, as it is the case for many ion transporters or regulators of ion transport.

New Sorex araneus karyotypes from Germany and the postglacial recolonization of central Europe

New G-banded karyotypes from populations of the common shrew Sorex araneus Linnaeus, 1758 provide a clearer picture of the distribution of chromosome races in central Europe. As expected according to their occurrence in neighbouring countries, the Jutland (kq, no), Laska (k/o) and Drnholec (ko, nr) races are also found in Germany. A new chromosome race "Rugen" (kq) is described from this Baltic Island. Together with the previously recorded races Ulm and Mooswald (kr), six chromosome races are now known from Germany. The resulting distribution pattern is characterized by high frequencies of different race-specific metacentrics at the periphery of the country and clines with decreasing frequencies towards the centre which is occupied by the Ulm race. This race is acrocentric for all chromosome arms involved in the observed race-specific fusions and represents a buffer between the surrounding, more metacentric races. According to the present distribution of these metacentrics, a scenario for the postglacial recolonization of central Europe by S. araneus populations on three different routes is proposed: from the east along the northern slopes of the Carpathian Arc, from the south-east along the Danube Valley and from the south-west through the Upper Rhine Valley.

An extension of the Marsden-Ratiu reduction for Poisson manifolds

We propose a generalization of the reduction of Poisson manifolds by distributions introduced by Marsden and Ratiu. Our proposal overcomes some of the restrictions of the original procedure, and makes the reduced Poisson structure effectively dependent on the distribution. Different applications are discussed, as well as the algebraic interpretation of the procedure and its formulation in terms of Dirac structures.

Remeis casolans per a bèsties i humans: medicina i veterinària popular a la catalunya central

Treball de recerca realitzat per un alumne d’ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l’any 2008. Consisteix en un diccionari informàtic que recull plantes i productes, cadascun amb les seves propietats medicinals i altres usos que se’ls atribueixen popularment i la forma de preparar remeis i aplicar-los per a cada malaltia o afecció. La informació s’ha extret de les entrevistes fetes a informants d’entre 60 i 90 anys del Bages, Berguedà i Solsonès, i es complementa amb un herbari i una mostra de preparacions dels remeis.

The added value from adopting a CGE approach to analyse changes in environmental trade balances

The application of multi-region environmental input-output (IO) analysis to the problem of accounting for emissions generation (and/or resource use) under different accounting principles has become increasingly common in the ecological and environmental economics literature in particular, with applications at the international and interregional subnational level. However, while environmental IO analysis is invaluable in accounting for pollution flows in the single time period that the accounts relate to, it is limited when the focus is on modelling the impacts of any marginal change in activity. This is because a conventional demand-driven IO model assumes an entirely passive supply-side in the economy (i.e. all supply is infinitely elastic) and is further restricted by the assumption of universal Leontief (fixed proportions) technology implied by the use of the A and multiplier matrices. Where analysis of marginal changes in activity is required, extension from an IO accounting framework to a more flexible interregional computable general equilibrium (CGE) approach, where behavioural relationships can be modelled in a more realistic and theory-consistent manner, is appropriate. Our argument is illustrated by comparing the results of introducing a positive demand stimulus in the UK economy using IO and CGE interregional models of Scotland and the rest of the UK. In the case of the latter, we demonstrate how more theory consistent modelling of both demand and supply side behaviour at the regional and national levels effect model results, including the impact on the interregional CO2 ‘trade balance’.

Official Central Bank Interventions in the Foreign Exchange Markets: A DCC Approach with Exogenous Variables

This paper assesses the impact of official central bank interventions (CBIs) on exchange rate returns, their volatility and bilateral correlations. By exploiting the recent publication of intervention data by the Bank of England, this study is able to investigate fficial interventions by a total number of four central banks, while the previous studies have been limited to three (the Federal Reserve, Bundesbank and Bank of Japan). The results of the existing literature are reappraised and refined. In particular, unilateral CBI is found to be more successful than coordinated CBI. The likely implications of these findings are then discussed.

Does the euro dominate Central and Eastern European money markets?

The so-called German Dominance Hypothesis (GDH) claimed that Bundesbank policies were transmitted into other European Monetary System (EMS) interest rates during the pre-euro era. We reformulate this hypothesis for the Central and Eastern European (CEE) countries that are on the verge of accessing the eurozone. We test this \Euro Dominance Hypothesis (EDH)" in a novel way using a global vector autoregressive (GVAR) approach that combines country-speci c error correction models in a global system. We nd that euro area monetary policies are transmitted into CEE interest rates which provides evidence for monetary integration between the eurozone and CEE countries. Our framework also allows for introducing global monetary shocks to provide empirical evidence regarding the e ects of the recent nancial crisis on monetary integration in Europe.

Flebotomíneos (Diptera: Psychodidae) no estado de Roraima, Brasil: I. espécies coletadas nas regiões sul e central

Durante 1987, nas regiões sul e central do Estado de Roraima, foram realizadas coletas de flebotomineos nas bases de árvores e em armadilhas CDC colocadas a 1,5 e 10m de altura do solo. Foram obtidos 2812 espécimes, de 45 espécies: 35 na região sul e 27 na região cental; 18 espécies foram comuns as duas áreas e 21 estão sendo aqui assinaladas pela primeira vez no Estado. A presente publicação eleva a 54 o número de espécies conhecidad no Estado.

Evolució del poblament i organització del territori a la Catalunya interior durant l'Antiguitat Tardana i l'Alta Edat Mitjana: els casos de la Catalunya Central (Bages, Berguedà i Solsonès) i la Garrotxa (segles V-X)

Projecte de recerca elaborat a partir d’una estada a la Université de Toulouse 2 – Le Mirail entre gener i juny del 2007. En concret, l’estada efectuada ha suposat la integració de qui signa aquesta memòria dins l’equip al-Andalus/Hispaniae, dirigit pel professor Philippe Sénac, una de les diverses branques que conformen el grup FRAMESPA d’aquella universitat, unitat de recerca adscrita al CNRS (UMR 5136). El títol proposat per al contingut de la recerca en la sol•licitud presentada, Evolució del poblament i organització del territori a la Catalunya interior a l’Alta Edat Mitjana, encapçalava un pla de treball que tenia per objectiu la recopilació i l’anàlisi de dades arqueològiques i textuals que oferissin un escenari a partir del qual establir una seqüència evolutiva en relació a les diferents tendències pel que fa al poblament tardoantic i altmedieval en dues zones diferenciades com són les conques mitjanes dels rius Llobregat i Cardener, a la Catalunya Central, i la capçalera del riu Fluvià, a la Garrotxa. Així, s’han pogut detectar, a partir de la contrastació de les diferents dades, fenòmens diversos que reflecteixen la incidència dels successius canvis històrics a nivell territorial i de poblament.

On an extension of the notion of Reedy category

"Vegeu el resum a l'inici del document del fitxer adjunt."

GLUTX1, a novel mammalian glucose transporter expressed in the central nervous system and insulin-sensitive tissues.

Based on homology with GLUT1-5, we have isolated a cDNA for a novel glucose transporter, GLUTX1. This cDNA encodes a protein of 478 amino acids that shows between 29 and 32% identity with rat GLUT1-5 and 32-36% identity with plant and bacterial hexose transporters. Unlike GLUT1-5, GLUTX1 has a short extracellular loop between transmembrane domain (TM) 1 and TM2 and a long extracellular loop between TM9 and TM10 that contains the only N-glycosylation site. When expressed in Xenopus oocytes, GLUTX1 showed strong transport activity only after suppression of a dileucine internalization motif present in the amino-terminal region. Transport activity was inhibited by cytochalasin B and partly competed by D-fructose and D-galactose. The Michaelis-Menten constant for glucose was approximately 2 mM. When translated in reticulocytes lysates, GLUTX1 migrates as a 35-kDa protein that becomes glycosylated in the presence of microsomal membranes. Western blot analysis of GLUTX1 transiently expressed in HEK293T cells revealed a diffuse band with a molecular mass of 37-50 kDa that could be converted to a approximately 35-kDa polypeptide following enzymatic deglycosylation. Immunofluorescence microscopy detection of GLUTX1 transfected into HEK293T cells showed an intracellular staining. Mutation of the dileucine internalization motif induced expression of GLUTX1 at the cell surface. GLUTX1 mRNA was detected in testis, hypothalamus, cerebellum, brainstem, hippocampus, and adrenal gland. We hypothesize that, in a similar fashion to GLUT4, in vivo cell surface expression of GLUTX1 may be inducible by a hormonal or other stimulus.

Prevalence of frailty indicators and association with socioeconomic status in middle-aged and older adults in a swiss region with universal health insurance coverage : a population-based cross-sectional study

Frailty prevalence in older adults has been reported but is largely unknown in middle-aged adults. We determined the prevalence of frailty indicators among middle-aged and older adults from a general Swiss population characterized by universal health insurance coverage and assessed the determinants of frailty with a special focus on socioeconomic status. Participants aged 50 and more from the population-based 2006-2010 Bus Santé study were included (N = 2,930). Four frailty indicators (weakness, shrinking, exhaustion, and low activity) were measured according to standard definitions. Multivariate logistic regressions were used to determine associations. Overall, 63.5%, 28.7%, and 7.8% participants presented no frailty indicators, one frailty indicator, and two or more frailty indicators, respectively. Among middle-aged participants (50-65 years), 75.1%, 22.2%, and 2.7% presented 0, 1, and 2 or more frailty indicators. The number of frailty indicators was positively associated with age, hypertension, and current smoking and negatively associated with male gender, body mass index, waist-to-hip ratio, and serum total cholesterol level. Lower income level but not education was associated with higher number of frailty indicators. Frailty indicators are frequently encountered in both older and middle-aged adults from the Swiss general population. Despite universal health insurance coverage, household income is independently associated with frailty.

Synanthropic trends in urban andextraurban taxocenoses of Sarcophaginae (Diptera) in three central european cities

An attempt has been made to characterize the synanthropic trends in Sarcophaginae of three Central European cities, viz. Brno, Bratislava and Budapest. The polar ordination of both sarcophagine taxa and of their taxocenoses revealed clear-cut trends towards culturophily and synanthropy in the male preconnubial aggregations of Sarchophaginae evidencing that this group of high Diptera represent an excellent model for the study of this phenomenon.