Evolution of Mycosphaerella graminicola at the wheat leaf and field levels

The aim of this study was to compare Mycosphaerella graminicola populations at the field and lesion levels. The evolution of M. graminicola populations from a single field in the “Morbihan” county (France), between 2005 and 2006, was first investigated for 37 strains using molecular fingerprinting by microsatellite markers (ST1A4, ST1E3, ST1E7 and ST1D7) and SSCP analysis of partial actin and β-tubulin encoding sequences. Similar gene diversity was observed in the 2005 and 2006 populations, with no common clones between the two years. This indicates frequent sexual recombination by the fungus. When considering each marker independently and comparing marker genetic variability for the two populations, differences in the genetic variability were detected in 2006 population compared to the 2005 population. ST1A4, ST1D7 and the partial sequence of actin presented a decrease in genetic variability of the 2006 strains, while for ST1E3, ST1E7 and the partial sequence of β-tubulin showed an increase, revealing the importance of the chosen markers. In addition, 29 strains collected in 2006 from three distinct lesions on the same wheat leaf in the “Nord” county were also investigated for genetic diversity. MAT1-1 and MAT1-2 were found in the same lesion offering opportunities for sexual contact

Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis

Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base

Controlling the Response: Predictive Modeling of a Highly Central, Pathogen-Targeted Core Response Module in Macrophage Activation

We have investigated macrophage activation using computational analyses of a compendium of transcriptomic data covering responses to agonists of the TLR pathway, Salmonella infection, and manufactured amorphous silica nanoparticle exposure. We inferred regulatory relationship networks using this compendium and discovered that genes with high betweenness centrality, so-called bottlenecks, code for proteins targeted by pathogens. Furthermore, combining a novel set of bioinformatics tools, topological analysis with analysis of differentially expressed genes under the different stimuli, we identified a conserved core response module that is differentially expressed in response to all studied conditions. This module occupies a highly central position in the inferred network and is also enriched in genes preferentially targeted by pathogens. The module includes cytokines, interferon induced genes such as Ifit1 and 2, effectors of inflammation, Cox1 and Oas1 and Oasl2, and transcription factors including AP1, Egr1 and 2 and Mafb. Predictive modeling using a reverse-engineering approach reveals dynamic differences between the responses to each stimulus and predicts the regulatory influences directing this module. We speculate that this module may be an early checkpoint for progression to apoptosis and/or inflammation during macrophage activation

Coordinate regulation of tissue macrophage and dendritic cell population dynamics by CSF-1

CSF-1 drives the homeostatic expansion of macrophages within the growing myometrium of pregnant mice by stimulating in situ proliferation and inducing monocyte precursor recruitment from the blood

Characterization of the monocyte to macrophage differentiation (MMD) protein and its homologue MMD2

During the course of this work the monocyte to macrophage differentiation factor (MMD) and its homologue MMD2 were characterized. Both genes encodes for orphan proteins with a predicted seven transmembrane domain very well conserved between species. MMD mRNA expression could be shown to be upregulated in macrophages and to be ubiquitously distributed in mouse and human. In contrast, MMD2 mRNA was only detected in brain and testis and in none of the tested cell lines. This differential expression pattern indicates differences in gene regulation although MMD and MMD2 share about 68% sequence identity at the protein level. Furthermore, mouse MMD (mMMD) regulation on the mRNA level was investigated in bone marrow macrophages and found to be rapidly induced by LPS, associating MMD function with processes that occur during the first stage of the macrophage innate activation. At the protein level, mMMD cellular localization and topology were determined. For this purpose various tagged versions of the protein were generated, and used to determine its subcellular localization. Additionally, a retroviral transfection system was established in our lab, and used to generate two cell lines stably expressing two tagged versions of MMD. By performing immunocytochemistry, tagged MMD proteins were localized in perinuclear compartments with an N(cytosol) and C(lumen) orientation. The second and main aim of this project was to investigate the effect of a MMD null-mutation in mice in an attempt to elucidate its function. For this purpose ES cell culture was established, MMD targeting constructs were generated and transfected into ES cells with the aim to generate an ES knock-out cell line and to establish an MMD knock-out mouse line by blastocyst injection. As an alternative to gene targeting, an siRNA sequence was determined that can be used for further analysis of MMD function

Conditions françaises de l'intéraction entre Mycosphaerella graminicola, agent de la septoriose du blé, et le blé (diversité et structure d'une population du champignon et modalités de la résistance et de la tolérance chez le blé)

Nous avons étudié les particularités françaises de l interaction entre le blé et M. graminicola. Dans un premier temps, l étude de la diversité et de la structuration de sous-populations françaises du champignon a été effectuée sur 364 souches provenant de 17 départements, en utilisant 4 marqueurs microsatellites (ST1A4, ST1E3, ST1E7 et ST1D7) et deux séquences partielles des gènes d actine et de b-tubuline analysées par PCR-SSCP. Les résultats obtenus ont confirmé le potentiel adaptatif du champignon en France, avec un faible flux de gène et une différenciation génétique modérée. La population française du champignon s est avérée plus structurée que les populations précédemment étudiées et nous suggérons la présence de deux populations fondatrices avec une région d admixion. Dans un second temps, nous avons étudié aux niveaux cytologique et biochimique les mécanismes de défenses chez 5 cultivars de blé français possédants différents profils de résistance (R) ou de tolérance (T) vis-à-vis de M. graminicola. Nous avons constaté que la R est liée à la présence de rares papilles, la sensibilité (S) est caractérisée par un développement intercellulaire du champignon alors que la T ne présente aucun impact sur le processus infectieux du champignon. Au niveau biochimique, les activités lipoxygénase (LOX), peroxydase (PO) et glutathion-S-transférase (GST) ne discriminent pas, à elles seules, les profils de R ou de T. Les études de corrélations entre les observations cytologiques et biochimiques et les différents profils permettent de lier la nécrose à l activité LOX chez les cultivars NT, l enroulement du tube germinatif autour du stomate à l activité PO chez les cultivars R et les pénétrations directes à l activité de la GST chez les cultivars S. En outre nous discriminons les cultivars S par leurs profils de T.We studied the interaction wheat-M. graminicola in the French conditions. At first, we looked at the diversity and the structure of M. Graminicola French populations. 364 strains collected from 17 counties were investigated using 4 microsatellite markers (ST1A4, ST1E3, ST1E7 et ST1D7) and 2 actin and b-tubuline partial sequences analyzed with PCR-SSCP. The obtained results confirmed the fungus high adaptation potential in France. We revealed a moderate genetic differentiation with a low gene flow. The population was found to be more structured than previously investigated ones, with 3 groups corresponding to 2 major clusters and a zone of admixture. We then looked at this interaction at cytological and biochemical level. We investigated 5 French wheat cultivars presenting different resistance (R) and tolerance (T) profiles towards M. Graminicola. We noticed that R whereas T presented no impact on the fungal infection process. Lipoxygenase (LOX), peroxidase (PO), and glutathione-S-transferase (GST) activities did not discriminate between R and T profiles. Correlations between cytological and biochemical data with the different R and T profiles revealed that necrosis correlates with LOX in NT cultivars, mycelia surrounding of stomata correlates with PO in R cultivars and direct penetrations correlates with GST in S cultivars. Moreover, we discriminated between S cultivars according to their T profile.CALAIS-BU Sciences (621932101) / SudocSudocFranceF

Allele-specific DNA methylation in mouse strains is mainly determined by cis-acting sequences

DNA methylation is a vital epigenetic mark that participates in establishing and maintaining chromatin structures and regulates gene transcription during mammalian development and cellular differentiation. Differences in epigenetic patterns between individuals may contribute to phenotypic variation and disease susceptibility; however, little is known about the extent of such variation or how different epigenetic patterns are established. Here we have compared DNA methylation profiles of macrophages from two inbred mouse strains (C57BL/6 and BALB/c) at 181 large genomic intervals that were selected based on differential gene expression patterns. Using a DNA methylation-dependent fractionation approach based on a combination of methyl-CpG immunoprecipitation and locus-wide tiling arrays, we identified several hundred differentially methylated regions, and simultaneously uncovered previously unrecognized genetic variability between both mouse strains at the studied loci. DNA sequence and methylation differences were validated by DNA sequencing and mass spectrometry analysis of bisulfite-treated DNA for a subset of regions. Importantly, we show that in F1 hybrids, the majority of strain-specific methylation patterns in somatic cells were maintained on the parental allele, regardless of their status in the male germ line. The common association of differentially methylated regions with sequence polymorphisms suggests that the genomic context determines the developmentally regulated epigenetic status at most nonimprinted regions of mammalian genomes

High power NVPF/HC-based sodium-ion batteries

International audienceThe Na-ion battery consisting of Na3V2(PO4)2F3 (NVPF) cathode and hard carbon (HC) anode has been developed and commercialized by Tiamat. This study focuses on the assessments of NVPF/HC-based prototype cells in a cylindrical cell format. The specific cell for this investigation has a capacity of 0.61 Ah, a specific energy of 68 Wh/kg, and an energy density of 135 Wh/L at 1C. The cycle life of this specific cell generation (2020) shows 1600 cycles at 5C charge and 5C discharge, but more recent cell generations show improved cycle stability: a trend of enhancement in cell cycle life is presented in the development timeline, and the latest version cell achieves a cycle life of 3200 cycles at 2C charge and 5C discharge. The cell shows excellent power rate capabilities up to 20C discharge and 10C charge. It is highlighted that >90 % of capacity and >80 % of energy (compared to 1C) can still be accessed at 20C discharge. Safety tests with different abuse conditions (overcharge, external heating, short circuit, and nail penetration) were performed. For all these abuse conditions, the specific cell version showed no thermal runaway. Thus, the NVPF/HC-based Na-ion technology seems to develop towards a well-suited candidate for high-power energy storage applications

Evolution of Mycosphaerella graminicola at the wheat leaf level and at the field level.

International audienceEvolution of M. graminicola wheat field populations from a given French county (Morbihan, 56) between years 2005 and 2006 was investigated for thirty seven strains using molecular fingerprinting by microsatellite markers (ST1A4, ST1E3, ST1E7, and ST1D7), and SSCP analysis study of partial actin and beta-tubulin encoding sequences. In addition, twenty nine strains collected from 3 distinct lesions on a same wheat leaf in 2006 in another French county (Nord, 59) were also investigated for genetic diversity. At the field level, we observed similar gene diversity in the 2005 and in the 2006 populations, with no common clones between the two years. This indicates frequent sexual recombination undergone by the fungus. When considering each marker independently and comparing genetic variability of the two populations, we noticed a decrease in genetic variability of the 2006 strains for three of them (ST1A4, ST1D7 and the partial sequence of actin) and an increase for ST1E3, ST1E7 and the partial sequence of beta-tubulin, revealing the importance of the chosen markers. At the lesion level, 69% of the studied strains were haplotypes with 31% of the clonal population found in 2 lesions out of 3. This suggests that at least parts of the lesions were formed after asexual reproduction and dissemination of pycnidiospores by splashing. We also confirmed the exploitative competition that exists between the strains at the lesion level