Recombinant myelin oligodendrocyte glycoprotein quality modifies evolution of experimental autoimmune encephalitis in macaques

The authors describe quantitatively and qualitatively different forms of experimental autoimmune encephalitis (EAE) in cynomolgus macaques. They found that bacterial contaminants within recombinant human myelin oligodendrocyte glycoprotein seemed to aggravate disease evolution. They provide anatomopathological features of fulminant and progressive forms of EAE, allowing them to distinguish specific factors influencing the evolution of this model of autoimmune demyelinating disease. Experimental autoimmune encephalitis (EAE) is a well-recognized model for the study of human acquired demyelinating diseases (ADD), a group of inflammatory disorders of the central nervous system (CNS) characterized by inflammation, myelin loss, and neurological impairment of variable severity. In rodents, EAE is typically induced by active immunization with a combination of myelin-derived antigen and a strong adjuvant as complete Freund's adjuvant (CFA), containing components of the mycobacterial wall, while myelin antigen alone or associated with other bacterial components, as lipopolysaccharides (LPS), often fails to induce EAE. In contrast to this, EAE can be efficiently induced in non-human primates by immunization with the recombinant human myelin oligodendrocyte glycoprotein (rhMOG), produced in Escherichia coli (E. coli), purified and formulated with incomplete Freund's adjuvant (IFA), which lacks bacterial elements. Here, we provide evidence indicating how trace amounts of bacterial contaminants within rhMOG may influence the course and severity of EAE in the cynomolgus macaque immunized with rhMOG/IFA. The residual amount of E. coli contaminants, as detected with mass spectrometry within rhMOG protein stocks, were found to significantly modulate the severity of clinical, radiological, and histologic hallmarks of EAE in macaques. Indeed, animals receiving the purest rhMOG showed milder disease severity, increased numbers of remissions, and reduced brain damage. Histologically, these animals presented a wider diversity of lesion types, including changes in normal-appearing white matter and prephagocytic lesions. Non-human primates EAE model with milder histologic lesions reflect more accurately ADD and permits to study of the pathogenesis of disease initiation and progression

Feeding behavior of neonate oblique banded leafroller: determination of ingested volumes by fluorescence spectroscopy

International audienc

Spécialisation d’hôte et structure des populations de Mycosphaerella graminicola, agent de la Septoriose du blé

National audienc

Population genetic structure and host specialization in the fungal plant pathogen Zymoseptoria tritici

National audienc

Population genetic structure and host specialization in the fungal plant pathogen Zymoseptoria tritici

National audienceZymoseptoria tritici causes Septoria tritici blotch of wheat, one of the most important diseases of this crop worldwide. Yield losses can reach 50% in disease-conducive climates and epidemics occur regularly both on hexaploid bread wheat (Triticum aestivum) and tetraploid durum wheat (Triticum turgidum ssp. durum). Isolates of Z. tritici exhibit both cultivar specificity (ability to infect only some cultivars of either bread or durum wheat) and host species specificity (ability to only infect one or the other wheat species). In France, the major bread wheat growing areas are located in the northern regions of the country whereas durum wheat is mainly cropped in the southern regions. Besides these traditional growing regions, both species are also cultivated in the ‘Centre’ region and in the southwestern region of France. In this study, we exploited these contrasted agrosystems to investigate, at a population level, the extent of host specialization in Z. tritici and to test whether this specificity towards bread or durum wheat had a significant effect on the genetic structure of the fungal populations. A set of 700 isolates were sampled from naturally infected fields of bread and durum wheat in four main French growing regions and genotyped using 12 microsatellite markers. The level of host specialization of 72 isolates from these populations was also determined by cross inoculation experiments on a panel of bread and durum wheat varieties

Influence of stress variation on radar wave propagation in concrete: Application to the monitoring of nuclear containment building

International audienceContainment buildings of nuclear power plants are made of prestressed concrete. Maintaining the tension in prestressing tendons is essential for the safety of these structures. However, steel and concrete can be subject to ageing and pathology (creep, shrinkage, corrosion…), this can lead to prestressing losses. It is then crucial to be able to know the tension state of tendons. Current techniques used to evaluate tension in cables are semi-destructive and are then unusable on containment buildings. This is why it is relevant to develop non-destructive techniques to evaluate potential prestressing losses. Based on the inaccessibility of the cables, this study suggests evaluating concrete stress rather than cable tension. This work particularly focuses on the influence of stress on radar wave propagation in concrete. Tests show that a compressive stress increase on concrete slabs leads to an isotropic delay in the electromagnetic signal and an anisotropic decrease in amplitude, more pronounced in the direction normal to the stress direction. These variations highly depend on concrete hydric state, as it is observed that an increase in stress on a near-saturation or an oven-dried concrete does not induce a signal variation. Finally, in-situ tests performed onto a mock-up of a nuclear containment building built by EDF confirm the sensitivity of radar waves to a variation of concrete stress

Septoriose et résistance aux fongicides. Enseignements de la saison 2010, notamment concernant les souches émergentes sur blé

Septoria tritici, champignon responsable de septoriose du blé, a continué à évoluer en 2010 malgré une faible pression globale de maladie. Les résistances spécifiques aux fongicides benzimidazoles et strobilurines restent bien implantées. Les résistances spécifiques aux SDHI restent absentes. En revanche les résistances aux IDM ont évolué notamment concernant les phénotypes émergents. Ces phénotypes, décelés en France depuis 2008, représentent 8 nouvelles souches identifiées. Elles sont toutes plus résistantes que les 8 phénotypes peu ou moyennement résistants connus auparavant. Elles sont classées en trois catégories dont une MDR. En 2010, la fréquence de ces souches émergentes, tant MDR que "non MDR" a augmenté. Elle reste faible. L'efficacité des fongicides n'a pas été affectée en pratique. Les raisons de cette situation et les évolutions probables sont discutées. Les stratégies anti-résistances envisageables pour préserver l'efficacité des produits sont évoquées

Evoked Potentials in Motor Cortical Local Field Potentials Reflect Task Timing and Behavioral Performance

Evoked potentials (EPs) are observed in motor cortical local field potentials (LFPs) during movement execution (movement-related potentials [MRPs]) and in response to relevant visual cues (visual evoked potentials [VEPs]). Motor cortical EPs may be directionally selective, but little is known concerning their relation to other aspects of motor behavior, such as task timing and performance. We recorded LFPs in motor cortex of two monkeys during performance of a precued arm-reaching task. A time cue at the start of each trial signaled delay duration and thereby the pace of the task and the available time for movement preparation. VEPs and MRPs were strongly modulated by the delay duration, VEPs being systematically larger in short-delay trials and MRPs larger in long-delay trials. Despite these systematic modulations related to the task timing, directional selectivity was similar in short and long trials. The behavioral reaction time was positively correlated with MRP size and negatively correlated with VEP size, within sessions. In addition, the behavioral performance improved across sessions, in parallel with a slow decrease in the size of VEPs and MRPs. Our results clearly show the strong influence of the behavioral context and performance on motor cortical population activity during movement preparation and execution

Oïdium, le cas triticale est riche d'enseignements. Caractérisation des populations d'oïdium infestant le triticale : révélation d'une nouvelle entité à l'origine de cette maladie émergente, et ses conséquences pour la sélection variétale

Depuis le début des années 2000. Les agronomes observent régulièrement de fortes infestations d'oïdium sur le triticale dans plusieurs pays européens, dont la France. Des variétés qui étaient résistantes lors de leurs inscription au catalogue sont maintenant totalement sensibles et nécessitent l'utilisation de fongicides. Cette maladie émergente peut se montrer très nuisible. Des pertes de rendement allant jusqu'à 20 % ont pu être observées dans de nombreuses situations d'infestation par l'oïdium. Parfois, cela va jusqu'à remettre en cause l'intérêt de l'utilisation du triticale

Leaf blotch on durum wheat in France:characterization of the species complex responsible of the disease with a focus on Parastagonospora nodorum

National audienc