Auxotrophy accounts for nodulation defect of most Sinorhizobium meliloti mutants in the branched-chain amino acid biosynthesis pathway

Some Sinorhizobium meliloti mutants in genes involved in isoleucine, valine, and leucine biosynthesis were previously described as being unable to induce nodule formation on host plants. Here, we present a reappraisal of the interconnection between the branched-chain amino acid biosynthesis pathway and the nodulation process in S. meliloti. We characterized the symbiotic phenotype of seven mutants that are auxotrophic for isoleucine, valine, or leucine in two closely related S. meliloti strains, 1021 and 2011. We showed that all mutants were similarly impaired for nodulation and infection of the Medicago sativa host plant. In most cases, the nodulation phenotype was fully restored by the addition of the missing amino acids to the plant growth medium. This strongly suggests that auxotrophy is the cause of the nodulation defect of these mutants. However, we confirmed previous findings that ilvC and ilvD2 mutants in the S. meliloti 1021 genetic background could not be restored to nodulation by supplementation with exogenous amino acids even though their Nod factor production appeared to be normal.Instituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Exacta

A Scalable Genome-Editing-Based Approach for Mapping Multiprotein Complexes in Human Cells

SummaryConventional affinity purification followed by mass spectrometry (AP-MS) analysis is a broadly applicable method used to decipher molecular interaction networks and infer protein function. However, it is sensitive to perturbations induced by ectopically overexpressed target proteins and does not reflect multilevel physiological regulation in response to diverse stimuli. Here, we developed an interface between genome editing and proteomics to isolate native protein complexes produced from their natural genomic contexts. We used CRISPR/Cas9 and TAL effector nucleases (TALENs) to tag endogenous genes and purified several DNA repair and chromatin-modifying holoenzymes to near homogeneity. We uncovered subunits and interactions among well-characterized complexes and report the isolation of MCM8/9, highlighting the efficiency and robustness of the approach. These methods improve and simplify both small- and large-scale explorations of protein interactions as well as the study of biochemical activities and structure-function relationships

Intermediate-term results after en bloc double-lung transplantation with bronchial arterial revascularization

AbstractObjective: Between May 1990 and January 1994, 18 patients underwent en bloc double-lung transplantation with tracheal anastomosis and bronchial arterial revascularization. Because at that time it was already suggested that chronic ischemia could be a contributing factor in occurrence of obliterative bronchiolitis, the purpose of this study was to evaluate, with a follow-up ranging from 22 to 69 months, the midterm effects of bronchial arterial revascularization on development of obliterative bronchiolitis. Results: Results were assessed according to tracheal healing, functional results, rejection, infection, and incidence of obliterative bronchiolitis. There were no intraoperative deaths or reexplorations for bleeding related to bronchial arterial revascularization, but there were three hospital deaths and five late deaths, two of them related to obliterative bronchiolitis. According to the criteria previously defined, tracheal healing was assessed as grade I, IIa, or IIb in 17 patients and grade IIIa in only one patient. Early angiography (postoperative days 20 to 40) demonstrated a patent graft in 11 of the 14 patients in whom follow-up information was obtained. Ten patients are currently alive with a 43-month mean follow-up. Among the 15 patients surviving more than 1 year, functional results have been excellent except in five in whom obliterative bronchiolitis has developed and who had an early or late graft thrombosis. Furthermore, those patients had a significantly higher incidence of late acute rejection (p < 0.02), cytomegalovirus disease (p < 0.006), and bronchitis episodes (p < 0.0008) than patients free from obliterative bronchiolitis. Conclusion: We conclude that besides its immediate beneficial effect on tracheal healing, long-lasting revascularization was, at least in this small series, associated with an absence of obliterative bronchiolitis, thus suggesting but not yet proving the possible role of chronic ischemia in this multifactorial disease. (J THORAC CARDIOVASC SURG 1996;112:1292-300

Utilisation des données Google Street View pour cartographier la distribution géographique des espèces. Une étude préliminaire de la processionnaire du pin (Thaumetopoea pityocampa)

Article publié suite à l'événement : MEDINSECT 3 ; Hammamet-Tunis (Tunisie) - (2012-05-08 - 2012-05-11).Mapping species distribution is an important and useful task to monitor invasive species spread or native species expansion under climate change. Unfortunately it requires a lot of occurrence data that are not easily available from literature and that are very time-consuming to collect in the field. For that reason, we designed a survey with the aim to explore to which extent large-scale databases such as Google Street View could be used to derive valid occurrence data. We worked with an insect species, the Pine Processionary Moth (PPM) Thaumetopoea pityocampa because the larvae of that moth build silk nests on its host tree that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google Street View. We designed a standardized procedure allowing the evaluation of the presence of the PPM on a large sampling grid (covering 46 848 km2) located in France. Field sampling has been conducted in parallel, which allowed a straightforward comparison between field and Google-derived datasets. Data derived from Google Street View were highly similar to field data as we found an accuracy (percentage of field values correctly predicted using Google Street View) of 92.9%. We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. More data are needed, however, to assess the range of spatial scales at which Google Street View actually provides reliable occurrence data.La cartographie de la distribution géographique des espèces est importante pour suivre l’évolution des aires de distribution d’espèces invasives ou d’espèces natives en expansion géographique. Malheureusement, les données nécessaires sont parfois difficilement accessibles à partir de la littérature et sont coûteuses à collecter sur le terrain. Pour cette raison, nous avons conçu une étude dans le but d'explorer dans quelle mesure il est possible d’utiliser les bases de données telles que Google Street View (GSV) pour obtenir des données d’occurrence valides. Nous avons choisi de travailler avec une espèce d’insecte, la chenille processionnaire du pin (PP) Thaumetopoea pityocampa car les larves de cette espèce se développent dans le feuillage des arbres hôtes et tissent un nid blanc aisément visible. La présence de l'espèce dans un site donné peut donc être facilement renseignée en examinant les vues panoramiques disponibles pour de nombreuses localités dans la base de données de Google Street View. Nous avons conçu une procédure standardisée permettant d'évaluer la présence de la PP à partir des données GSV et nous l’avons mise en oeuvre sur une aire d’étude couvrant 46 848 km2dans la région Centre en France. La distribution de l’espèce a également été décrite à l’aide d’échantillonnages réalisés sur le terrain. Les données issues de l’examen des images Google Street View ont été comparées aux données de terrain et se sont révélées de bons estimateurs de la présence de la processionnaire du pin avec une précision (proportion de valeurs correctement estimées) de 92.9% sur notre zone d’étude pour un maillage de 16 km x 16 km. Ces résultats suggèrent que l’exploitation des bases de données de GSV pourrait permettre de produire des données écologiques intéressantes pour les espèces dont la présence peut être estimée visuellement à partir de photographies. Des études complémentaires sont cependant nécessaires pour mieux cerner la gamme d’échelles spatiales auxquelles GSV fournit des données d’occurrence fiables

Auxotrophy accounts for nodulation defect of most Sinorhizobium meliloti mutants in the branched-chain amino acid biosynthesis pathway

Some Sinorhizobium meliloti mutants in genes involved in isoleucine, valine, and leucine biosynthesis were previously described as being unable to induce nodule formation on host plants. Here, we present a reappraisal of the interconnection between the branched-chain amino acid biosynthesis pathway and the nodulation process in S. meliloti. We characterized the symbiotic phenotype of seven mutants that are auxotrophic for isoleucine, valine, or leucine in two closely related S. meliloti strains, 1021 and 2011. We showed that all mutants were similarly impaired for nodulation and infection of the Medicago sativa host plant. In most cases, the nodulation phenotype was fully restored by the addition of the missing amino acids to the plant growth medium. This strongly suggests that auxotrophy is the cause of the nodulation defect of these mutants. However, we confirmed previous findings that ilvC and ilvD2 mutants in the S. meliloti 1021 genetic background could not be restored to nodulation by supplementation with exogenous amino acids even though their Nod factor production appeared to be normal.Instituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Exacta

Grey matter density changes of structures involved in Posttraumatic Stress Disorder (PTSD) after recovery following Eye Movement Desensitization and Reprocessing (EMDR) therapy

International audienc

Metabolic adaptation to a high-fat diet is associated with a change in the gut microbiota

Objective The gut microbiota, which is considered a causal factor in metabolic diseases as shown best in animals, is under the dual influence of the host genome and nutritional environment. This study investigated whether the gut microbiota per se, aside from changes in genetic background and diet, could sign different metabolic phenotypes in mice. Methods The unique animal model of metabolic adaptation was used, whereby C57Bl/6 male mice fed a high-fat carbohydrate-free diet (HFD) became either diabetic (HFD diabetic, HFD-D) or resisted diabetes (HFD diabetes-resistant, HFD-DR). Pyrosequencing of the gut microbiota was carried out to profile the gut microbial community of different metabolic phenotypes. Inflammation, gut permeability, features of white adipose tissue, liver and skeletal muscle were studied. Furthermore, to modify the gut microbiota directly, an additional group of mice was given a glucooligosaccharide (GOS)-supplemented HFD (HFD+GOS). Results Despite the mice having the same genetic background and nutritional status, a gut microbial profile specific to each metabolic phenotype was identified. The HFD-D gut microbial profile was associated with increased gut permeability linked to increased endotoxaemia and to a dramatic increase in cell number in the stroma vascular fraction from visceral white adipose tissue. Most of the physiological characteristics of the HFD-fed mice were modulated when gut microbiota was intentionally modified by GOS dietary fibres. Conclusions The gut microbiota is a signature of the metabolic phenotypes independent of differences in host genetic background and diet

The genomic basis of color pattern polymorphism in the Harlequin ladybird

© 2018 The Authors Many animal species comprise discrete phenotypic forms. A common example in natural populations of insects is the occurrence of different color patterns, which has motivated a rich body of ecological and genetic research [1–6]. The occurrence of dark, i.e., melanic, forms displaying discrete color patterns is found across multiple taxa, but the underlying genomic basis remains poorly characterized. In numerous ladybird species (Coccinellidae), the spatial arrangement of black and red patches on adult elytra varies wildly within species, forming strikingly different complex color patterns [7, 8]. In the harlequin ladybird, Harmonia axyridis, more than 200 distinct color forms have been described, which classic genetic studies suggest result from allelic variation at a single, unknown, locus [9, 10]. Here, we combined whole-genome sequencing, population-based genome-wide association studies, gene expression, and functional analyses to establish that the transcription factor Pannier controls melanic pattern polymorphism in H. axyridis. We show that pannier is necessary for the formation of melanic elements on the elytra. Allelic variation in pannier leads to protein expression in distinct domains on the elytra and thus determines the distinct color patterns in H. axyridis. Recombination between pannier alleles may be reduced by a highly divergent sequence of ∼170 kb in the cis-regulatory regions of pannier, with a 50 kb inversion between color forms. This most likely helps maintain the distinct alleles found in natural populations. Thus, we propose that highly variable discrete color forms can arise in natural populations through cis-regulatory allelic variation of a single gene. More than 200 distinct color forms have been described in natural populations of the harlequin ladybird, Harmonia axyridis. Gautier et al. show that this variation is controlled by the transcription factor Pannier. Pannier is necessary to produce black pigment, and its expression pattern prefigures the coloration pattern in each color form