Dissertations / Theses on the topic 'Bruce L'

Lo scopo della presente ricerca è sottolineare la tendenza alla ossessiva e spesso superflua ricerca del simbolismo nell’analisi di opere, specificatamente testi letterari e film, e proporre una possibile soluzione per porre fine o almeno diminuire gli effetti del fenomeno. A partire da una definizione esaustiva della parola simbolo, l’analisi verterà sull’evoluzione del concetto di simbolismo attraverso i media, e il cambiamento intrinseco causato da tale evoluzione. In seguito, analizzerò un semisconosciuto ma emblematico sondaggio, condotto nel 1973 da Bruce McAllister, all’epoca studente, che interrogò acutamente numerosi autori riguardo al loro rapporto con il simbolismo, ponendo l’accento su alcune delle risposte da lui ricevute, che gettano una luce rivelatrice sul symbol hunting e symbol planting. Dopodiché scenderò ancor più nel dettaglio, esemplificando con due storie brevi: Signs and Symbols (Segni e Simboli), di Vladimir Nabokov e Big Two-hearted River (Grande fiume a due cuori) di Hernest Hemingway. Dopodiché, analizzerò il falso simbolismo come luogo cinematografico, ponendo l’accento sugli aspetti di planting e hunting, e mi avvarrò dell’aiuto di due film significativi sul tema realizzati in tempi recenti, ovvero Inception (2010) e Memento (2000), di Christopher Nolan, che possono essere interpretati come una meta-critica dell’abuso di simboli, e rappresentano una pietra miliare nell’analisi di symbol planting e symbol hunting. In conclusione, proporrò la mia personale possibile soluzione, ovvero il prendere le opere d’arte in qualunque forma, specialmente di fiction, “così come sono”, separandole e scindendole dalle proprie aspettative. È necessario prendere in considerazione un ritorno alla letteralità, per poter avvicinarsi maggiormente alla vera anima di una storia, di un libro, di un film, altrimenti esiste la possibilità che tutto ciò che guardiamo o vediamo sia per sempre irrimediabilmente contaminato dalla nostra dimensione privata.

The purpose of this essay is to analyze the ideology of the cultural phenomenon, that is as political as it is controversial, the new atheism. By studying the ideas and values of four prominent new atheists, commonly referred to as the ‘four horsemen of the new atheism’, Richard Dawkins, Sam Harris, Christopher Hitchens, and Daniel Dennett, this study aims to, in some ways challenge, and in others, nuance, the categorization of the movement. Its adherents have often been labeled as, for example: ‘secular fundamentalists’, ‘evangelical’ and ‘radical secularists’. None of these designations are inherently wrong. But I think there is a more fitting term available: ‘societal secular maximalist’. This term is a modified version of ‘religious maximalism’, coined by the historian of religion at the University of Chicago, Bruce Lincoln. I argue that the new atheist ideology is not fundamentalistic because it admits fallibility if another theory where to disprove it within its own scientific discourse. Considering this fact, it does not hold is central ideological feature, most commonly a Darwinist theory of evolution, as absolute. Due to this, and some other factors, I argue that the societal secular maximalist categorization is more fitting because the scientific and humanistic views of the ‘four horsemen’ lay claim to all aspects of human existence, private and public, emotional, and factual along with the morals, ethics and aesthetics of our societies.

La structure génétique des trypanosomes du complexe brucei est toujours sujette à discussion. La définition classique des différentes sous espèces ne semble pas satisfaisante. Face à une diversité de formes cliniques (allant de formes asymptomatiques à des formes aigues) et une diversité de réponses aux tests de dépistage (malades, séropositifs et suspects sérologiques), il est important de mieux cerner la structure génétique et le mode de reproduction du pathogène. Nous avons, à partir de prospection médicales menées en Côte d’Ivoire et en Guinée, caractérisé les trypanosomes directement à partir des liquides biologiques en plus de la caractérisation des souches isolées par les différentes techniques d’isolement (KIVI et IR) et ceci avec des marqueurs microsatellites plus polymorphes que les isoenzymes. Il ressort de cette étude que les isoenzymes sont inadaptées pour caractériser les pathogènes d’un groupe assez homogène comme celui du groupe 1 de T. B. Gambiense. Les résultats obtenus avec les microsatellites montrent que le groupe 1 de T. B. Gambiense présente bien une structure clonale, monophylétique avec un génome assez stable dans le temps. Les microsatellites utilisés ont montré une bonne spécificité, permettant de rendre compte d’une structuration géographique entre différents foyers de THA. Ils ont également montré que des trypanosomes infectants pour l’homme circulent chez des patients non confirmés en parasitologie (qui pourraient agir comme réservoir humain de la maladie) et une aptitude différentielles des trypanosomes à l’isolement. En revanche, ces microsatellites se sont montré incapables de détecter des infections mixtes. Ces résultats permettent d’envisager des études visant à corréler la diversité génétique observée chez les pathogènes et la diversité de réponses à l’infection mais également de cibler les gènes qui confèrent la résistances des pathogènes au sérum humain et aux médicaments par l’élaboration d’un plus grand échantillon de marqueurs microsatellites<br>Genetic structure of Trypanosoma brucei complex is still under debate. Classical taxonomy of this parasite is far from relating actual situation in field. Indeed, regard to the diversity of response to diagnosis test, together with the diversity of symptoms encountered in HAT, it is important to elucidated population structure and mating system of this pathogen. We characterised trypanosomes both from stocks isolated by two techniques (KIVI and RI) and biological fluid, using polymorphic microsatellite markers and isoenzymes (gold standard). Isoenzymes were shown unsuitable to differentiate stocks from T. B. Gambiense group 1 since it’s homogeneous. Results from microsatellite markers are consistent with clonal structure, monophyletic and genome stability through time of T. B. Gambiense group 1 pathogens. Microsatellite markers displayed a high specificity which allowed geographic clusters among HAT foci. They also point out that human infectious trypanosomes circulate in parasitological non confirmed patient (who could act as human reservoir of HAT) and a fitness behaviour of trypanosome when face to isolation but could not detected multiple infections. Our results allow us to further investigate correlation between genetic diversity seen in Trypanosoma brucei and diversity of response observed in patients and characterised human serum and drug resistance genes with more microsatellite markers

African trypanosomiasis is a neglected tropical disease affecting both animals and humans in sub-Saharan Africa. The disease is caused bythe protozoan parasite Trypanosoma brucei, which is transmitted by the tsetse fly (Glossina sp.) vector. In animals, infection leads to severe muscle atrophy and anaemia resulting in significant production and economic losses. In humans, infection leads to both neurological and cardiac dysfunction and can be fatal if untreated. While the neurological-related pathogenesis is well studied, and indeed is responsible for the colloquial name “Sleeping Sickness”, the cardiac pathogenesis remains unknown. Previous studies interpreted cardiac dysfunction as being due to immune/inflammatory responses. However, recent work examining the parasite’s interaction with the blood brain barrier, the traversal of which is important for development of neurological signs, has identified direct immune/inflammatory independent mechanisms involving calcium (Ca2+) signalling. The current study exposed isolated ventricular cardiomyocytes and adult rat hearts to T. brucei to test whether trypanosomes can alter Ca2+ signalling and cardiac function independent of a systemic immune/inflammatory response. Using a high-throughput method of observing spontaneous contractile activity in isolated cardiomyocytes, we were able to determine that the presence of T. b. brucei parasites resulted in more cardiomyocytes exhibiting spontaneous contractile events. Moreover, when the parasites were removed by careful centrifugation, the culture supernatant had the same effect. Confocal Ca2+ imaging identified an increase in the frequency of arrhythmogenic spontaneous diastolic sarcoplasmic reticulum (SR)-mediated Ca2+ release (Ca2+ waves). Studies utilising specific inhibitors, recombinant protein and RNA interference all demonstrated that this altered SR function was due to cathepsin-L; a cysteine protease produced by T. brucei (TbCatL). Experiments utilising a Langendorff perfusion method revealed that trypanosome culture supernatant could induce ventricular premature contractions in 50% of a cohort of ex vivo whole rat hearts. Mechanistic experiments were performed on single isolated cardiomyocytes stimulated at 1.0 Hz and perfused first with control media followed by trypanosome culture supernatant. The protocol utilised triple caffeine applications: (i) prior to stimulation to empty the SR of Ca2+, (ii) after perfusion with control media and after supernatant to determine the SR Ca2+ content and sarcolemmal extrusion of Ca2+ following each solution. Results were normalised to a parallel set of cardiomyocytes perfused with control media only as time controls. These experiments revealed a 10-15% increase in SR Ca2+ reuptake by the SR Ca2+ ATPase (SERCA) but a reduced SR Ca2+ content suggesting a concomitant increase in SR-mediated Ca2+ leak. This conclusion was supported by the data demonstrating that TbCatL increased Ca2+ wave frequency. These effects were abolished by autocamtide-2-related inhibitory peptide (AIP), highlighting a role for Ca2+/calmodulin kinase II (CaMKII) in the TbCatL action on SR function. When cytosolic diastolic Ca2+ was measured in cardiomyocytes with SR function inhibited by ryanodine and thapsigargin, trypanosome supernatant prevented a decline in cytosolic diastolic Ca2+ that was observed in control media. AIP did not abolish this effect suggesting that TbCatL may raise diastolic Ca2+ that could activate CaMKII leading to the observed effects. These data demonstrated for the first time that African trypanosomes alter cardiac function independent of a systemic immune response via a mechanism involving extracellular cathepsin-L-mediated changes in SR function. Utilising the same (culture adapted and monomorphic) strain of T. brucei as the in vitro experiments, Lister 427, in a rat model of infection we found no significant increase in the arrhythmia frequency as measured by a 15 min electrocardiogram (ECG). However, when hearts were removed and Langendorff perfused with the addition of isoproterenol the arrhythmia frequency was increased. When the pleomorphic strain T. b. brucei TREU 927 was used in rats with continuous ECG recording from biopotential telemetry there was a significant increase in arrhythmia frequency in the infected rats. When hearts were removed and Langendorff perfused with isoproterenol there was a similar increase in arrhythmia frequency as observed with the 427 infected hearts. This suggests that a cardiac dysfunction phenotype is present during trypanosome infections in an animal model providing the basis for future therapeutic work. The relationship between arrhythmogenic SR-mediated Ca2+ release and TbCatL has parallels with endogenous extracellular cathepsin-L (CatL). It has been demonstrated that a basal level of CatL is necessary for normal cardiac function. However, in coronary heart disease (CHD) CatL levels are increased in the serum of patients correlating with the severity of disease. The effects of raised CatL on cardiac function remain unknown. Work in our lab has identified that ex vivo Langendorff perfused hearts that have undergone a 30 min period of ischaemia followed by 90 min reperfusion show greater CatL activity in coronary effluent than hearts perfused without ischaemia. In addition, preliminary data collected in this thesis suggest that human patients that have suffered a myocardial infarction and have undergone reperfusion via percutaneous coronary intervention (PCI) showed higher CatL levels in post-reperfusion serum samples compared to pre-reperfusion serum. When severity of heart function in patients (measured as left ventricular volume at systole and diastole, ejection fraction, infarct size and area at risk) was assessed by magnetic resonance imaging (MRI) in a preliminary study, there was a positive correlation with serum CatL levels. Using recombinant CatL on isolated rat ventricular cardiomyocytes it was found that the SR Ca2+ content and the stimulated Ca2+ transient were significantly reduced in a concentration dependent manner. This suggests a CatL dependent SR dysfunction. This conclusion was supported by an increase in Ca2+ wave frequency measured by confocal Ca2+ imaging in isolated cardiomyocytes. The work in this thesis demonstrates a role for both mammalian-derived and exogenous extracellular cathepsin-L proteases in arrhythmogenic SR-mediated Ca2+ release.

Laminaria digitata est une algue brune au cycle de vie digenetique tres heteromorphe. Le sporophyte diploide est macroscopique, le gametophyte haploide est microscopique. Le sporophyte concentre l'iode jusqu'a 30,000 fois sa teneur dans l'eau de mer et produit en grande quantite l'alginate, son polysaccharide parietal majeur. Le gametophyte comme le tres jeune sporophyte sont des plantes d'ombre extreme, necessitant tres peu de lumiere pour croitre. Les genomes exprimes dans les deux phases du cycle de vie ont ete etudies et compares par une strategie est (etiquette de sequence transcrite). Pres de 700 sequences differentes ont ete produites, dont la moitie a ete identifiee par similitude avec des sequences presentes dans les banques de donnees. A la vue des transcriptomes, le sporophyte apparait comme un organisme en croissance active investissant la plupart des ses ressources dans la synthese proteique. Un transcrit codant une haloperoxydase est majoritairement exprime. Le gametophyte investi principalement ses ressources dans la synthese proteique, mais aussi dans la photosynthese. Ces resultats sont accord avec les donnees ecophysiologiques. Le gametophyte apparait comme un organisme moins differencie qui exprime peu de transcrits abondants et aucun transcrit majoritaire. L'analyse des donnees de sequencage, a permis de mieux connaitre la structure du genome transcrit de cette algue dont l'utilisation des codons ou la sequence de kozak qui sont directement applicables dans le laboratoire. Pour gerer l'ensemble des donnees, une base de donnees relationnelle et un ensemble de logiciels connexes ont ete mis en place formant un lims (laboratory information management system). Cette strategie a permis d'isoler de nombreux clones codant des proteines d'interet. Certains, impliques dans le metabolisme du carbone, ont ete caracterises. Pour d'autres, comme la bromoperoxydase probablement impliquee dans le metabolisme de l'iode ou la c-5-epimerase impliquee dans le metabolisme de l'alginate, l'etude des proteines et des familles multigeniques est en cours. Les resultats obtenus ont permis de developper de nouvelles thematiques au laboratoire. De plus, l'acces par d'autres laboratoires a ces resultats devrait permettre de nouveaux developpements de la connaissance de la biologie des algues brunes.

La diversite genetique des isolats de phytophthora megakarya provenant de quelques pays d'afrique centrale (cameroun, gabon et sao tome) et d'afrique de l'ouest (nigeria, togo et ghana) a ete etudiee par des marqueurs biochimiques (isozymes) et moleculaires (rapd). La separation de cette espece en deux grands groupes correspond bien a la separation biogeographique observee chez d'autres plantes et organismes en afrique, ce qui amene a supposer l'existence de deux sous-especes de p. Megakarya. La reproduction sexuee existerait chez cette espece, et la localite de ibule au nigeria semble etre le centre de diversite pour la sous-espece afrique de l'ouest. Un test d'inoculation artificielle de feuilles de cacaoyer a ete developpe et utilise pour caracteriser les relations hote-parasite. De tres faibles effets d'interactions entre souches et clones ont ete deceles. Cependant, ils ne modifient pas significativement les classements de clones, confirmant l'absence de pathotypes chez p. Megakarya avec l'echantillon etudie. Differents niveaux d'agressivite ont ete observes entre les souches, mais ne semblent pas lies a leur origine geographique. Le test feuille a ete mis en oeuvre sur le terrain, en comparaison avec le test d'inoculation artificielle sur fruits et le taux de pourriture observe au champ, sur des clones et sur des descendances provenant d'un essai diallele. Les resultats du test d'inoculation sur feuille s'averent plus stables que ceux du test sur fruit. Les correlations genetiques entre le test feuille et le test fruit sont positives, tandis que les correlations environnementales sont negatives. La resistance evaluee par le test feuille est fortement correlee aux taux de pourriture lorsqu'on etudie les effets moyens d'un clone ou d'une descendance ; par contre le niveau de cette correlation diminue quand on etudie les effets d'arbres individuels a l'interieur d'un clone ou d'une descendance. Le test sur feuille semble donc adapte a la caracterisation en pepiniere de clones ou de familles hybrides par leur sensibilite moyenne.

La diagnose de phytophthora megakarya et de p. Palmivora agents de la pourriture brune des cabosses du cacaoyer (theobroma cacao l. ) a d'abord ete verifiee a l'aide des electrophoretypes enzymatiques notamment avec les phosphogluco-isomerases (pgi) et les malate-deshydrogenases (mdh). Les travaux qui ont suivi ont eu alors pour objectifs l'utilisation de facteurs pouvant influencer l'expression specifique ou non specifique des caracteres observables, mycologiques et pathogeniques: croissances et caracteres morphoculturaux sur milieu de culture semi-naturel a des ph et sous des eclairements differents, developpements sur milieu synthetique en presence de differents additifs (oligoelements, beta-sitosterol), glucides ou polysaccharides, composes phenoliques. Quelques activites enzymatiques et le comportement infectieux sur epicotyles de semenceaux de cacaoyer ont ete egalement etudies alors que les donnees quantitatives ont ete exploitees par les methodes statistiques inferentielles et que les classements statistiques ont ete obtenus par differents tests (de duncan, de newman et keuls), les donnees qualitatives ont ete analysees, seules ou conjointement avec les donnees quantitatives, par des methodes descriptives comme l'analyse factorielle par composantes principales (acp) et les analyses factorielles des correspondances (afc) ou discriminantes (afd). Les typologies obtenues ont permis d'identifier des axes possibles de differenciations ou de strategies adaptatives de la pathogenie

La production des cals depend de l'origine spatiale des explants et de la periode de recolte de l'algue. Ainsi, seuls les dix premiers centimetres de la zone meristematique stipofrondale fournissent le maximum de cals et le printemps est la meilleure periode pour la culture in vitro. Les cals sont constitues soit d'une masse indifferenciee de cellules, soit de cellules filamenteuses dont certaines montrent des structures ressemblant a des gametophytes males et femelles capables d'initier des plantules. Les milieux de culture employes montrent qu'il n'est pas necessaire d'utiliser un milieu complexe pour que les cals se developpent, l'addition de sucres ou d'hormones n'apportant aucune amelioration. Les semences obtenues peuvent etre utilisees pour l'etude de la parthenogenese, de la cryoconservation ou de la bioencapsulation tout comme des prothalles issus de spores. L'obtention de plantules par germination parthenogenetique des gametophytes femelles n'est possible qu'a condition de les isoler avant la maturation des males. L'utilisation d'un gradient discontinu de percoll permet de les separer des le stade embryospore, avant un ultime tri sur plaque de gelose. L'apparition et la croissance des parthenosporophytes depend de la temperature et de l'eclairement. Trois types morphologiques sont rencontres: des plantules normales, des plantules depourvues de tout systeme de fixation et des plantules ayant perdu partiellement ou totalement leur polarite. L'analyse structurale et l'etude des proprietes photosynthetiques des parthenosporophytes n'ont montre aucune difference significative avec les sporophytes issus d'une fusion des gametes. L'analyse des noyaux au cytometre de flux montre que ce sont des diploides faibles faisant penser a une duplication spontanee des chromosomes, indispensable pour la viabilite des plantules. La cryoconservation des gametophytes de cette algue revele que le taux de survie estime soit par microscopie, soit par fluorescence est fonction de la quantite et de la nature du cryoprotecteur. Ces gametophytes peuvent etre encapsules dans des billes d'alginate de calcium avant la cryoconservation

Myo-inositol is ubiquitous in nature and is found at the structural core of a diverse range of biologically important derivatives, including phosphatidylinositols, inositol phosphates and mycothiol. The synthesis of myo-inositol derivatives is notoriously difficult due to the need to control both regio- and enantioselectivity. As a result, synthetic routes to derivatives of this type are often lengthy and low yielding. The first biosynthetic step in the production of all myo-inositol metabolites is the isomerisation of D-glucose 6- phosphate to L-myo-inositol 1-phosphate as mediated by L-myo-inositol 1-phosphate synthase (INO1). For the protozoan parasite Trypanosoma brucei, INO1 is essential for survival and its version of the enzyme (TbINO1) has a high turnover. This makes TbINO1 an attractive candidate for the biocatalytic production of L-myo-inositol 1- phosphate, and a potential starting point for drastically shortened syntheses of important myo-inositol derivatives. The production of L-myo-inositol 1-phosphate by TbINO1 has been optimised to achieve complete conversion in reaction conditions that facilitate product isolation. Due to problems with an in-batch process, the TbINO1 enzyme was immobilised and the process was transferred to a flow system. This has allowed for production of significant quantities of L-myo-inositol 1-phosphate with a high level of purity. L-myo-inositol 1- phosphate obtained from the flow system has been used to prepare mycothiol glycosylation acceptor, 1,2,4,5,6-penta-O-acetyl-D-myo-inositol, in a concise synthesis with a greatly improved yield over the literature.

Made available in DSpace on 2014-07-29T15:16:27Z (GMT). No. of bitstreams: 1 Ariane_Castro_Mendes_Leao[1].pdf: 899082 bytes, checksum: 0b19f24baa0e56f0caae9f29a959bb7a (MD5) Previous issue date: 2006-12-15<br>The common bean besides being one of the basic meals of brazilian´s population, it is one of the main products that provide protein in the nutritional diet from the society share which is economically less favorable. The identification of molecular markers linked to controlling genes of the protein content in common beans (Phaseolus vulgaris L.) is a very important tool to help breeding programs, raising the efficiency and agility. This way, this work was made with two main goals: a) to map SSR and RAPD markers linked to loci (QTLs) that control protein content in two generations of a segregating population of common beans and b) to compare detection procedures of markers linked to QTLs using the ANOVA method and the process of interval mapping. For that reason, 94 families were taken from the F2 generation and 90 families from the F2:3 generation derived from the cross of genitors CNFC 7812 e CNFC 8056. Results indicated that there is the possibility of identifying molecular markers related to protein content in common beans, utilizing both detection procedures. The ANOVA method identified a greater number of QTLslinked markers than the process of interval mapping in both generations. There was coincidence between the identified loci obtained with the two methods for each generation. Loci that were associated with protein content were different for the F2 and F2:3 generations. However, there was a stable detection of a genomic region of the linkage group 4, indicating a possible role of this region of the common bean genome in the control of seed protein content. The proportion of the trait s phenotypic variation explained by QTLs varied from 5,5% to 9,5%, considering both generation.<br>O feijão, além de se constituir um dos alimentos básicos da população brasileira, é um dos principais produtos fornecedores de proteína na dieta alimentar dos estratos sociais economicamente menos favorecidos. A identificação de marcadores moleculares ligados a genes controladores de teor de proteína em feijoeiro-comum (Phaseolus vulgaris L.) é uma importante ferramenta para auxiliar os programas de melhoramento, aumentando sua eficiência e agilidade. Desta forma, este trabalho foi realizado com os objetivos: a) mapear marcadores SSR e RAPD ligados aos locos gênicos (QTLs) controladores de teor de proteína em duas gerações de uma população segregante de feijoeiro-comum e b) comparar os processos de detecção dos marcadores ligados aos QTLs utilizando o método de ANOVA e o método de mapeamento por intervalo. Para tanto, foram utilizadas 94 famílias da geração F2 e 90 famílias da geração F2:3 provenientes do cruzamento entre os genitores CNFC 7812 e CNFC 8056. Os resultados mostraram a possibilidade de identificar marcadores moleculares ligados ao teor de proteína em feijoeiro, utilizando ambos os métodos. O método de ANOVA identificou mais marcadores ligados a QTLs do que o processo de mapeamento por intervalo em ambas as gerações. Houve concordância entre os locos identificados pelos dois métodos para cada geração. Os locos que foram associados com o teor de proteína foram distintos para as gerações F2 e F2:3. Entretanto, houve uma detecção estável de uma região genômica do grupo de ligação 4, indicando um possível papel desta região do genoma do feijoeiro no controle do teor de proteína no grão. A proporção da variância fenotípica desta característica explicada pelos QTLs variou de 5,5% a 9,5%, considerando as duas gerações.

L'influence de fractions aqueuses (5000, 10000, 20000 da) de l'algue brune ascophyllum nodosum et de conservateurs antimicrobiens a ete testee sur deux lignees fibroblastiques (l. 929, humaine). Les effets de ces produits ont ete recherches par l'evaluation de certaines criteres tels que la croissance (numeration, taux de proteines totales) et la viabilite (rouge neutre, tetrazolium) cellulaires. Le travail mene sur les extraits de l'ascophyllum a ete complete par des observations de l'ultrastructure et de la morphologie des deux types fibroblastiques. L'optimisation de la sensibilite du test au tetrazolium a ete abordee par la methodologie de la recherche experimentale: matrices d'hadamard et de doelhert. L'etude menee sur l'ascophyllum nodosum revele d'une part un effet stimulant important de la fraction a 5000 da sur la croissance cellulaire et la capacite d'endocytose lysosomale et, d'autre part une inhibition des diverses activites cellulaires plus marquee si le poids moleculaire de la fraction aqueuse augmente. Cependant, il faut noter que l'inhibition de la croissance cellulaire est un phenomene reversible. La classification des esters de l'acide parahydroxybenzoique (methyle, propyle, benzyle) fait apparaitre un accroissement de leur potentiel cytotoxique en fonction de l'augmentation de la longueur de la chaine alkyle. De plus, une comparaison entre les index de cytotoxicite de ces conservateurs montre une bonne correlation entre les trois tests colorimetriques utilises (bleu de coomassie, rouge neutre, tetrazolium)

The trypanolytic factor of human serum :a trojan horse.<p><p><p>African trypanosomes, the prototype of which is Trypanosoma brucei, are protozoan parasites of huge clinical, veterinary and economical importance. They develop in the body fluids of various mammals (including humans) where they face and manipulate many different aspects of the immune system. The extent of this interplay is pivotal to both host and parasite survival, and depending on parasite virulence and host susceptibility, infection duration ranges from some months to several years. At the end, host survival is invariably compromised.<p><p>Humans and few other primates provide however a striking exception to this fatal outcome. They are indeed fully protected against most trypanosome infections through the presence in their blood of a so-called trypanosome lytic factor (TLF). The TLF is known to circulate mainly in the form of a high density lipoprotein particle characterized by the simultaneous presence of two primate-specific proteins: haptoglobin-related protein (Hpr) and apolipoprotein L-I (apoL-I).<p><p>We have contributed to delineate the respective roles played by Hpr and apoL-I in the lysis process.<p><p>ApoL-I was shown to be the exclusive toxin of the TLF. In its absence humans get fully susceptible to any trypanosome infection. The toxin was shown to kill the parasite after endocytosis through the generation of ionic pores in the lysosomal membrane. Those pores dissipate membrane potential and trigger the influx of chloride ions from the cytoplasm into the lysosomal compartment, leading to an eventually fatal uncontrolled osmotic phenomenon. <p><p>ApoL-I efficient delivery to the parasite relies on Hpr. African trypanosomes indeed fulfil their heme nutritional requirements by receptor-mediated internalization of the complex formed by haptoglobin, an evolutionary conserved acute-phase protein, and hemoglobin, resulting from physiological intravascular hemolysis. This heme uptake by the auxotrophic parasites contributes to both growth rate and resistance against host oxidative burst. In human serum, the trypanosome receptor is unable to discriminate between Hp and the closely related TLF-bound Hpr, explaining TLF efficient endocytosis.<p><p>As such, the TLF acts as a Trojan horse, killing the parasite from inside the cell after having deceived its vigilance through the high similarity between heme-delivering haptoglobin and toxin-associated Hpr. <p><br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished

L'arachide (Arachis Hypogea), principale culture de rapport au Sénégal, subit lors des longs stockages (8 a 13 mois) de redoutables infestations de la bruche Caryedon Serratus (OL. ). Ces contaminations peuvent se développer à partir des adultes qui subsistent dans les lieux de stockage, mais comme c'est le cas chez d'autres bruchidae, l'hypothèse d'une préinfestation en plein champ n'est pas à exclure. En effet, après arrachage, les arachides sont laissés sur le champ 1 a 2 mois en andains pour le séchage, puis en meule avec leurs stockages ultérieurs. On sait par ailleurs que C. Serratus peut se développer sur plusieurs espèces de Caesalpiniaceae sauvages, dont nous avons régulièrement suivi la phénologie et le niveau d'infestation des gousses par cette bruche. L'étude de la biologie, au laboratoire, ne fait pas apparaître de différences majeures selon l'origine de la souche, mais nos résultats semblent montrer une importance particulière de Tamarindus Indica dans la biologie de C. Serratus pour la zone d'étude considérée. Nos résultats indiquent également : - que les Caesalpiniaceae sauvages suivies dans le site d'étude, restent infestées d'une année sur l'autre, malgré l'absence (parfois 3 a 5 mois) de toute gousse sur certains arbres (durant la saison des pluies, par exemple); - le niveau de pré-infestation des arachides au champ, dépend de la distance des andains à ces Caesalpiniaceae hôtes (cet effet se mesure sur des distances assez courtes, de l'ordre d'une dizaine de mètres), et du temps d'exposition des arachides durant le séchage au champ. Les adultes responsables de cette pré-infestation proviendraient des Caesalpiniaceae hôtes des T. Indica en particulier. La simulation au laboratoire de stocks paysans montre une grande variabilité dans l'évolution de la contamination : chaque stock semble constituer un cas particulier. La prise en compte de l'incidence des Caesalpiniaceae hôtes sur la dynamique de contamination des arachides pourrait aider à mieux raisonner la lutte contre C. Serratus.

Resumé<p>La pourriture brune de la cabosse de Theobroma cacao L. induite par Phytophthora palmivora est un maladie qui à l’échelle mondiale, cause de sérieuses pertes dans les plantations de cacao. L'utilisation de fongicides est coûteuse et est nuisible pour l'environnement. L'utilisation de micro-organismes est une alternative écologique<p>attractive pour les producteurs. L’objectif de ce travail est d’isoler et de caractériser des rhizobactéries de T. cacao avec une activité antagoniste contre Phytophthora palmivora, l'agent causal de la pourriture des cabosses. Parmi les 127 rhizobactéries isolés, trois isolats CP07, CP24 et CP30, identifiées comme Pseudomonas chlororaphis, ont montré une activité<p>antagoniste in vitro et in vivo contre P. palmivora. <p>La production d'enzymes lytiques, de sidérophores, de biosurfactants et d’HCN, ainsi que la détection de gènes codant pour des antibiotiques, la formation de biofilm et la mobilité des bactéries ont également été évalués pour les trois souches de rhizobactérie.<p>Le séquençage du génome de CP07 a confirmé la présence de gènes codant pour trois types de sidérophores, d’HCN, de phénazines et de biosurfactants de la famille de la viscosine, notamment. Un mutant de CP07 déficient dans la production viscosine a été généré et les études effectuées sur ce mutant indiquent que ce bio-tensioactif particulier est essentiel à la fois pour la mobilité bactérienne et pour la formation de biofilm, mais pas pour l'antagonisme in vitro contre Phytophthora, bien qu'il puisse contribuer à la bioprotection de T. cacao.<p>Cette étude fournit une base théorique pour l'utilisation potentielle de P. chlororaphis<p>CP07 comme un agent de lutte biologique pour la protection des plantes de cacao contre l'infection par P. palmivora.<p><p><p>Abstract<p>The black pod rot in Theobroma cacao L. is a major problem worldwide and in Cuba, is<p>one of the most important diseases. The use of chemical fungicides is expensive and<p>harmful to the environment. The use of microorganisms is an environmentally<p>attractive alternative for producers. In this work, fluorescent Pseudomonas strains were<p>isolated from cocoa rhizosphère. The in vitro antagonistic activity and bioprotection<p>against Phytophthora palmivora (Butler) was evaluated. Three strains with in vitro<p>antagonistic activity and bioprotection, CP07, CP24 and CP30, belonging to the species Pseudomonas chlororaphis, were obtained. P. chlororaphis CP07 was highlighted for the best behavior in vitro and in vivo. P. chlororaphis CP07 produces siderophores, HCN,<p>biosurfactants, exoproteases, lipases and motility (swarming and twitching). Genome<p>sequencing confirmed the presence of genes encoding three types of siderophores, HCN, phenazines, the biosurfactant viscosin, and exoproteases, among others. A mutant impaired in biosurfactant production was constructed. When the mutant was characterized, it was evident that the biosurfactant was not involved in the antagonistic effect in vitro against P. palmivora Mab1, although it is crucial to the motility and the ability to form biofilms. P. chlororaphis CP07 was selected as a potential biological control agent against Phytophthora.<br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished

De nombreuses etudes ont ete realisees sur la vigne, le mout ou le vin, mais peu de recherches ont ete consacrees a la seve. Les stades phenologiques majeurs : debourrement, floraison, veraison et maturite ont ete parfaitement decrits mais aucune etude ne recense les differentes substances presentes a ces epoques. L'analyse de la seve brute du cepage cabernet franc aux quatre stades phenologiques, sur plusieurs millesimes, dans la region de bordeaux, montre que la teneur globale en acides amines varie avec l'annee. La presence constante, en quantite significative d'un groupe de huit acides amines a ete notee : asparagine/glutamine, tyrosine, arginine, acide aspartique, acide glutamique, histidine et proline. Les concentrations de ces constituants dans la seve varient en fonction du millesime pour un meme stade phenologique. Aussi, une differenciation, par analyse statistique, des stades phenologiques est possible. De meme, des acides amines specifiques pour chaque millesime ont ete mis en evidence. L'influence du sol sur la composition en acides amines de la seve a egalement ete etudiee. La seve brute du cepage cabernet franc de trois types de sols de precocite differente, dans la region de saumur, a ete analysee. Les teneurs globales en acides amines varient pour un meme stade en fonction de cette precocite. La nature des acides amines dominants reste inchangee par rapport a bordeaux. Les memes acides amines sont presents aux divers stades pour les trois parcelles. Certains acides amines pourraient etre en relation avec la precocite de la vigne, a l'exemple de l'asparagine/glutamine, l'acide aspartique, la proline et la valine. D'autres (serine, acide glutamique, threonine, glycine, alanine, histidine et tyrosine) semblent au contraire etre en relation avec le caractere tardif de la parcelle au debourrement.

Concernant le domaine des relations plantes-insectes, ce travail montre qu'Acanthoscelides obtectus say, coléoptère, bruchidae, est un insecte phytophage ravageur bien adapté à sa plante-hôte, Phaseolus vulgaris L. , même s'il peut aisément se reproduire sur d'autres espèces de légumineuses d'intérêt alimentaire pour les pays en développement, comme le Niebe (vigna unguiculata) et la fève (vicia faba). Des plantes et extraits aromatiques de la flore tempérée, appartenant en particulier a la faille des labiées, et leurs molécules allèlochimiques exercent un effet protecteur, résultat d'un effet létal sur les insectes adultes et d'une inhibition de la reproduction (diminution de la ponte, effets ovicides et larvicides) limitant le renouvellement des générations. L'activité des huiles essentielles et de leurs composés majoritaires monoterpénoïques déterminés par chromatographie en phase gazeuse est mise en evidence ainsi que celles des composes allelochimiques de nature polyphénolique qui perturbent la physiologie de l'insecte. Ainsi les plantes aromatiques possèdent en leur sein un véritable arsenal moléculaire de défense contre cet insecte et peuvent révéler ainsi un caractère protecteur pour les graines de légumineuses.

Copies of author's previously published works inserted.<br>Bibliography: leaves 160-168.<br>v, 183 leaves : ill. ; 30 cm.<br>Title page, contents and abstract only. The complete thesis in print form is available from the University Library.<br>Describes the preparation and characterization of a series of 6A-amino-substituted {beta}-cyclodextrins<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999

In conclusion, the present study successfully demonstrate BJ as a potent anti-pancreatic cancer herb; BD is the main ingredient for its cytotoxic and apoptotic effects on the pancreatic cancer cells through activation of the redox-sensitive p38-MAPK signaling pathway and reduction of anti-apoptotic activity by inhibition of NF-kappaB activation in pancreatic cancer cells. The in vivo efficacy and low toxicity of BD render this chemical compound to be a potential for its further development into an anti-pancreatic cancer agent.<br>In recent decades, the application of Chinese herbal medicine has become an increasingly popular approach and alternative to treating cancer. Moreover, Chinese herbal medicine is the source for the discovery of novel anti-cancer drugs. For example, irinotecan and topotecan, the analogues of camptothecin which is isolated from the bark and stem of Camptotheca acuminate are found to be effective in ovarian, lung and colon cancers. Given that Chinese medicine is commonly used in the treatment of cancers, we postulate that Chinese herbs are a valuable source to possess anti-pancreatic cancer compounds. Accordingly, the aims of the present project are: (1) to screen Chinese medicinal herbs which has the most potent cytotoxic activity in pancreatic cancer cells in vitro; (2) to isolate and identify the effective compound in Brucea javanica (BJ) which mediates apoptosis in pancreatic cancer cell lines; (3) to study the mechanistic pathways involved in brucein D - (BD, a quassinoid found in abundance in BJ) mediated apoptosis in pancreatic cancer in vitro; and (4) to evaluate the efficacy of BD in pancreatic cancer using an xenograft animal model of pancreatic cancer.<br>In vivo study demonstrated that daily administration of BD through intravenous injection for ten days in nude mice bearing pancreatic cancer cells effectively reduced tumor growth in terms of tumor weight and size, while showing no significant toxicity in heart, liver and kidney tissues of the mice.<br>Nine Chinese medicinal herbs were selected for the screening experiment and, among them, BJ exhibited the most potent cytotoxic action on the three pancreatic adenocarcinoma cell lines, namely PANC-1, SW-1990 and CAPAN-1, with IC50 values of 2.5mug/ml, 5.1mug/ml and 1.5mug/ml, respectively. BD, one of the main chemical compounds found in BJ was found to possess strong apoptogenic effect in PANC-1 cells, as evidenced by DNA condensation and fragmentation, sub-G1 phase formation, proteolytic activation of caspase 3, 8 and 9, and attenuation of bcl-2 activity. Further mechanistic studies revealed that the apoptotic signals generated by BD were transduced from the cell membrane to nucleus via the mediation of p38-MAPK signaling pathway while the reactive oxygen species (ROS) was found to accumulate in BD-treated PANC-1 cells. The activation p38-MAPK phosphorylation was inhibited by pretreatment with an antioxidant. However, the inhibition of NF-kappaB activity and downregulation of anitapoptotic genes in BD-treated cells was independent of the ROS changes.<br>Pancreatic cancer is the forth and sixth leading cause of cancer deaths in the United States and Hong Kong, respectively. The morbidity of pancreatic cancer is almost equal to its mortality rate. Poor diagnosis and intrinsic resistance to chemotherapy are the major characteristics for pancreatic cancer. Therefore, new therapeutic strategy is urgently warranted to overcome the drug-resistance challenge in the management of pancreatic cancer.<br>Lau Sin Ting Cynthia.<br>Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: .<br>Thesis (Ph.D.)--Chinese University of Hong Kong, 2009.<br>Includes bibliographical references (leaves 228-271).<br>Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Abstract also in Chinese.

Summaries in Afrikaans and English<br>In hierdie navorsingsverslag word die representasie van die reg en die verskynsel van die verhoor as romangegewe in enkele tekste van André P. Brink ondersoek. Die studie vind plaas binne die interdissiplinêre konteks van die reg en die letterkunde. Die studie: (i) fokus op die rol wat die reg in die literêre teks vervul; (ii) ondersoek uitbeeldings van die verhoor soos wat dit in Brink se romankuns aangetref word; en (iii) ondersoek die fiksionalisering van historiese en dokumentêre regsbronne met spesifieke verwysing na sekere eksemplariese Brink-­‐romans.<br>In this research report, representations of the law and of the trial, as embedded in certain novels by André P. Brink, are explored. The study is structured within the interdisciplinary field of law and literature. This study: (i) focuses on the role of law within the literary text; (ii) explores the legal delineation of a trial in novels by Brink; and (iii) explores the fictionalisation of historic and documentary judicatory resources with specific reference to exemplary texts by Brink.<br>Afrikaans & Theory of Literature<br>M.A. (Afrikaans)