Genome structure and pathogenicity of the fungal wheat pathogen Mycosphaerella graminicola

The phytopathogenic fungus Mycosphaerella graminicola (Fuckel) J. Schröt. in Cohn (asexual stage: Zymoseptoria tritici (Desm.) Quaedvlieg & Crous) causes septoria tritici leaf blotch (STB) in wheat and is one of the most important diseases of this crop worldwide. However, STB control, mainly based on the use of resistant cultivars and fungicides, is significantly hampered by the limited understanding of the genetic and biochemical bases of pathogenicity, and mechanisms of infection and resistance in the host. M. graminicola has a very active sexual cycle under field conditions, which is an important driver of STB epidemics. Moreover, it results in high genetic diversity of field populations that causes a major challenge for the development and sustainable management of resistant cultivars and the discovery of new antifungal compounds. Understanding the role of the sexual and asexual life cycles on genome composition of this versatile pathogen and its infection strategy is crucial in order to develop novel control methods. Chapter 1 is an introduction to the biology and pathogenicity of M. graminicola. In addition, it shortly describes the impact of improved and novel technologies on the speed, scope and scale of comparative genomics research. Chapter 2 provides detailed genetic analyses of two M. graminicola mapping populations, using mainly DArT markers, and the analysis of the meiotic transmission of unequal chromosome numbers. Polymorphisms in chromosome length and number were frequently observed in progeny isolates, of which 15–20% lacked one or more chromosomes despite their presence in one or both parents, but these had no apparent effect on sexual and pathogenic fitness. M. graminicola has up to eight so called dispensable chromosomes that can be easily lost - collectively called the dispensome - which is, so far, the highest number of dispensable chromosomes reported in filamentous fungi. They represent small-sized chromosomes and make up 38% of the chromosome complement of this pathogen. Much of the observed genome plasticity is generated during meiosis and could explain the high adaptability of M. graminicola in the field. The generated linkage map was crucial for finishing the M. graminicola genome sequence. Chapter 3 describes the M. graminicola genome sequence with highlights on genome structure and organization including the eight dispensable chromosomes. The genome comprises a core set of 13 chromosomes and a dispensome, consisting of eight chromosomes that are distinct from the core chromosomes in structure, gene and repeat content. The dispensome contains a higher frequency of transposons and the genes have a different codon use. Most of the genes present one the dispensome are also present on the core chromosomes but little synteny is observed neither between the M. graminicola dispensome and the core chromosomes nor with the chromosomes of other related Dothideomycetes. The dispensome likely originates from ancient horizontal transfer(s) from (an) unknown donor(s). Chapter 4 shows a global analysis of proteins secreted by M. graminicola in apoplastic fluids during infection. It focuses mainly on fungal proteins secreted in a compatible interaction. The study showed that many of the annotated secreted proteins have putative functions in fungal pathogenicity, such as cell wall degrading enzymes and proteases, but the function of a substantial number of the identified proteins is unknown. During compatible interactions proteins are primarily secreted during the later stages. However, many pathogenesis-related host proteins, such as PR-2, PR-3 and PR-9, accumulated earlier and at higher concentrations during incompatible interactions, indicating that fungal effectors are recognized by resistant plants and trigger resistant gene-mediated defence responses, though without a visible hypersensitive response. Chapter 5 further details the initial identification and characterization of necrosis-inducing proteins that are produced in culture filtrates (CFs) of M. graminicola. The necrosis-inducing activity of CFs is light dependent and inactivated by proteinase K and heat treatment (100C). This is reminiscent of the necrosis-inducing properties of host selective toxins of other Dothideomycete pathogens such as Stagonospora nodorum and Pyrenophora tritici-repentis. Subsequent purifications of CFs and mass spectrometry identified several candidate proteins with necrosis-inducing activity. Heterologous expression of the two most prominent proteins in Pichia pastoris produced sufficient quantities for infiltration assays in a panel of wheat cultivars that showed differential responses, suggesting specific recognition. Chapter 6 provides a general discussion of the thesis and puts the results obtained in a broader perspective with a focus on the genome structure of M. graminicola and its function. In addition, aspects of the hemi-biotrophic lifestyle, the relevance of secreted proteins for the wheat-M. graminicola pathosystem in relation to gene-for-gene models and the potential implications for resistance breeding strategies are discussed. </p

Les facteurs explicatifs de la passivité ou de la neutralité des investisseurs institutionnels vis-àvis du contrôle des firmes de leurs portefeuilles.

L’objet de cet article est de déterminer les principaux facteurs qui empêchent les investisseurs institutionnels d’exercer leur rôle d’actionnaire dans les firmes de leurs portefeuilles. L’étude montre que la passivité ou la neutralité des actionnaires institutionnels vis à vis du système du contrôle de la firme peut être expliquée par quatre facteurs principaux : les contraintes légales et réglementaires, les problèmes de l’action collective de contrôle, les problèmes d’agence et de groupes d’intérêt et l’insuffisance du système d’évaluation et d’incitation des dirigeants des institutions financières.investisseurs institutionnels, contrôle, portefeuille, finance

Relations entre les firmes et les actionnaires institutionnels : promotion de l'investissement relationnel.

L’investissement relationnel est un nouveau mécanisme de contrôle des dirigeants par les investisseurs institutionnels. La pratique de cette forme de contrôle suppose la détention d'une part importante de capital, sur un horizon long et un engagement réciproque entre les investisseurs institutionnels, les administrateurs et les dirigeants sur la politique de la firme et les prises des décisions. L’investissement relationnel est basé sur la construction d’une relation capital / gestion étroite et durable. Il s’exerce surtout au moyen de la négociation. La pratique de l’investissement relationnel permet de réduire l’asymétrie informationnelle, les coûts de transaction et les coûts d’agence. Du côté de l’entreprise, ce mécanisme de contrôle permet de protéger les dirigeants contre les prises de contrôle hostiles et donc d’avoir une vision de long terme sur l’industrie. Toutefois, les investisseurs relationnels peuvent être opportunistes et cherchent de profiter de leurs relations aux dirigeants pour réaliser des gains privés. Enfin, les investisseurs institutionnels peuvent ne pas avoir de l'expertise suffisante pour gérer l'entreprise.investisseurs institutionnels, investissement relationnel, contrôle, entreprise, relation

Characterizations environmental and energy of the biomethanisation industrial applied to avicolous biomass in Tunisia

This work consists in studying the alkaline fermentation, applied to the avicolous droppings, established on the level of the digester controls industrial Sousse Hammam. The analytical follow-up of this digester related, on the one hand, to the determination of certain characteristics of the avicolous effluent by the analysis of the physicochemical parameters (pH and Dry Matter: DM) and environmental (Suspended matter: SM and Asks Biological out of Oxygen: DBO5), and in addition, on the energy follow-up by the appreciation of the qualitative productivity (Composition in Biomethane and Calorific value) of produced biogas. At the end of the experimentation implemented, the synthesis of the principal results is the following one: - The best assessments of depollution are obtained on the level of the mud tank as well concerning SM as the DBO5. - The interest of the recourse to the purification of produced biogas was shown by comparing the results before and after purification as well on gas the composition plan as on the calorific value level. - The installation of Biomethanisation considered requires some improvements for a better qualitative energy productivity, a better reduction of the power polluting of the droppings and a better valorization of the solid and liquid residues

Le principe d'individualisation à l'épreuve des peines minimales d'emprisonnement : étude comparée des systèmes de justice pénale français et canadien

Le terme d’individualisation désigne la faculté de modulation de la peine par le juge selon la nature de l’infraction et les caractéristiques propres au contrevenant. Cette faculté du juge fera l’objet d’une étude comparée sous le prisme des peines minimales d’emprisonnement : peines obligatoires imposées par le législateur pour certaines infractions et qui s’imposent aux juges. Ces dernières, très controversées en France comme au Canada, semblent constituer un obstacle à la personnalisation de la sanction entrainant déséquilibres et injustices dans la détermination de la peine

Making Room for Horror: The Adversity of Genre in the French Film Industry

This dissertation examines the lack of legitimacy that French horror cinema encounters within France’s domestic industry. In a country dominated by a cultural elitism that values art films over genre films, French horror faces multiple challenges from its initial funding to its final reception as a result of rigid television broadcast rules, strict exhibition visa authorizations, and moral conflicts regarding their use of violence. Building on historical and theoretical research as well as empirical data from institutional reports, roundtables, interviews and audience surveys, this dissertation investigates the invisibility of horror in the processes of the French film industry and seeks to find alternate circuits of production, distribution and exhibition that could benefit the genre. The second chapter (the introduction being the first) delves into the history of the horror genre in France in order to understand the lack of recognition it suffers from. Chapter 3 discusses the modes of financing and production operating in France and draws a comparison with the American film industry through the dual experience of director Alexandre Aja who has worked in both countries. Chapter 4 analyzes the regulation of cinematic violence imposed by the state and its unfortunate consequences on the distribution of horror films while considering the notion of affect that is especially relevant to the visceral content of the genre. Chapter 5 deconstructs the French preference for theatrical release by focusing on other modes of distribution like festivals, video-on-demand and streaming platforms. It also includes an interview of Frédéric Garcia who developed a French horror show with Netflix. The last chapter shifts the focus to spectators and addresses their viewing habits and appraisal of French horror by way of a survey distributed online

Reconfiguration de l'ordre mondial de l'information et de la communication: implications et incidences de la chaine Al Jazira

Reconfiguración del orden mundial de la información y de la comunicación: implicaciones e incidencias de la cadena Al Yazira La información es la base de la toma de decisión. Los gobiernos a través de la Historia entendieron la influencia de este soft power en su política interior como exterior. Los Estados nacidos de la descolonización notaron sobre todo el desequilibrio de sus fuentes y sus consecuencias en términos de dominación cultural e intelectual. Esta tesis entonces pregunta cómo dar una voz al « Sur ». Analiza el enfoque de los principales actores implicados en el ideal de un « Nuevo orden mundial de la información y de la comunicación »: el Movimiento de los No-alineados y la UNESCO. Sus aproximaciones siendo inter-gubernamentales, la cuestión de la voluntad política se subraya. Así aparece en nuestro pensamiento un actor no-intergubernamental sobrepasando el consentimiento estatal y modificando el orden establecido: la cadena Al Yazira que emite una información internacional por profesionales árabes. Iniciada antes de las revoluciones árabes, esta tesis pregunta finalmente en qué medida el reequilibrio de la información mundial por la cadena catarí ayuda en la democratización tanto de la sociedad internacional como de los Estados que ella cubre principalmente : los del mundo árabe.Reconfiguration of the World Order of Information and Communication: implication and impact of the channel Al Jazeera Information is the basis for decision making. Governments throughout History have understood the impact of this soft power in their domestic and foreign policy. States emerging from decolonization have especially noted the imbalance of its sources and its consequences in terms of cultural and intellectual domination. This thesis investigates on how to give a voice to the "South". It analyzes the approach of the main actors involved in the ideal of a "New World Order of Information and Communication", the Non-Aligned Movement and UNESCO. They adopted an inter-governmental approach so the issue of the States’ political will is emphasized. Then a non-intergovernmental actor bypassing the States’ consent has been launched and has changed the established order: the channel Al Jazeera broadcasted international information made by Arab professionals. Started before the Arab revolutions, this thesis eventually asks to what extent Al Jazeera’s rebalancing of global information helps democratizing both the international society and the States the channel mainly covers: those of the Arab world

Valorisations environnementale, énergétique et agronomique de la biométhanisation industrielle appliquée à la biomasse avicole récupérée en Tunisie

This work consists on the study of the methanic fermentation, applied to the chicken manure, at an industrial pilot digester of Hammam Sousse (Tunisia). The analytical monitoring of the digester has focused on the one hand, on the determination of certain characteristics of the chiken effluent by the analysis of the physicochemical and environmental parameters, and on the other hand, on energy monitoring by assessing the qualitative productivity of the produced biogas. Furthermore, the present study focused on the partial substitution of the Gross Sylvicole Compost (CSB), produced locally, by the chicken methacompost. The agronomic evaluation of the chicken methacompost was based on Acacia cyanophylla germination and plant growth. Upon completion of the experiment, the best assessments of the depollution on the liquid digestate are obtained at the setting basin. The interest of purification of the biogas was shown by comparing the results before and after purification in terms of gaseous composition and calorific value. The incorporation of chicken methacompost with the CSB haa a remarkable positive effect on germination, and consequently, on the growth of the seedlings, in terms of height and diameter. Keywords: Industrial digester, chicken manure, depollution balances, gaseous composition, Calorific value, chicken methacompost.&nbsp;Le présent travail consiste à étudier la fermentation méthanique, appliquée aux fientes avicoles, établie au niveau du digesteur pilote industriel de Hammam Sousse (Tunisie). Le suivi analytique de ce digesteur a porté, d’une part, sur la détermination de certaines caractéristiques de l’effluent avicole par l’analyse des paramètres physico-chimiques et environnementaux, et d’autre part, sur le suivi énergétique par l’appréciation de la productivité qualitative du biogaz produit. En outre, la présente étude s’est intéressée à la substitution partielle du Compost Sylvicole Brut (CSB), produit localement, par le méthacompost avicole. Le suivi a porté sur la germination et la croissance des plants d’Acacia cyanophylla. Au terme de l’expérimentation mise en œuvre, les meilleurs bilans de dépollution quant au digestat liquide sont obtenus au niveau du bassin de décantation. L’intérêt du recours à l’épuration du biogaz a été démontré en comparant les résultats avant et après épuration tant sur le plan composition gazeuse que sur le plan pouvoir calorifique. L’incorporation du méthacompost avicole avec le CSB a un effet positif remarquable sur la germination, et par suite, sur la croissance des plants, en termes de hauteur et de diamètre. Mots-Clés: Digesteur industriel, fientes avicoles, bilans de dépollution, composition gazeuse, pouvoir calorifique, méthacompost avicole. &nbsp

HIV-2 Protease resistance defined in yeast cells

BACKGROUND: Inhibitors of the HIV-1 Protease currently used in therapeutic protocols, have been found to inhibit, although at higher concentrations, the HIV-2 encoded enzyme homologue. Similar to observations in HIV-1 infected individuals, therapeutic failure has also been observed for some patients infected with HIV-2 as a consequence of the emergence of viral strains resistant to the anti-retroviral molecules. In order to be able to define the specific mutations in the Protease that confer loss of susceptibility to Protease Inhibitors, we set up an experimental model system based in the expression of the viral protein in yeast. RESULTS: Our results show that the HIV-2 Protease activity kills the yeast cell, and this process can be abolished by inhibiting the viral enzyme activity. Since this inhibition is dose dependent, IC(50 )values can be assessed for each anti-retroviral molecule tested. We then defined the susceptibility of HIV-2 Proteases to Protease Inhibitors by comparing the IC(50 )values of Proteases from 7 infected individuals to those of a sensitive wild type laboratory adapted strain. CONCLUSION: This functional assay allowed us to show for the first time that the L90M substitution, present in a primary HIV-2 isolate, modifies the HIV-2 Protease susceptibility to Saquinavir but not Lopinavir. Developing a strategy based on the proposed yeast expressing system will contribute to define amino acid substitutions conferring HIV-2 Protease resistance

Ga and Gß Proteins Regulate the Cyclic AMP Pathway That Is Required for Development and Pathogenicity of the Phytopathogen Mycosphaerella graminicola

We identified and functionally characterized genes encoding three G alpha proteins and one G beta protein in the dimorphic fungal wheat pathogen Mycosphaerella graminicola, which we designated MgGpa1, MgGpa2, MgGpa3, and MgGpb1, respectively. Sequence comparisons and phylogenetic analyses showed that MgGPA1 and MgGPA3 are most related to the mammalian G alpha(i) and G alpha(s) families, respectively, whereas MgGPA2 is not related to either of these families. On potato dextrose agar (PDA) and in yeast glucose broth (YGB), MgGpa1 mutants produced significantly longer spores than those of the wild type (WT), and these developed into unique fluffy mycelia in the latter medium, indicating that this gene negatively controls filamentation. MgGpa3 mutants showed more pronounced yeast-like growth accompanied with hampered filamentation and secreted a dark-brown pigment into YGB. Germ tubes emerging from spores of MgGpb1 mutants were wavy on water agar and showed a nested type of growth on PDA that was due to hampered filamentation, numerous cell fusions, and increased anastomosis. Intracellular cyclic AMP (cAMP) levels of MgGpb1 and MgGpa3 mutants were decreased, indicating that both genes positively regulate the cAMP pathway, which was confirmed because the WT phenotype was restored by adding cAMP to these mutant cultures. The cAMP levels in MgGpa1 mutants and the WT were not significantly different, suggesting that this gene might be dispensable for cAMP regulation. In planta assays showed that mutants of MgGpa1, MgGpa3, and MgGpb1 are strongly reduced in pathogenicity. We concluded that the heterotrimeric G proteins encoded by MgGpa3 and MgGpb1 regulate the cAMP pathway that is required for development and pathogenicity in M. graminicola