Design of Fe3–xO4 raspberry decorated graphene nanocomposites with high performances in lithium-ion battery

Fe3–xO4 raspberry shaped nanostructures/graphene nanocomposites were synthesized by a one-step polyol-solvothermal method to be tested as electrode materials for Li-ion battery (LIB). Indeed, Fe3–xO4 raspberry shaped nanostructures consist of original oriented aggregates of Fe3–xO4 magnetite nanocrystals, ensuring a low oxidation state of magnetite and a hollow and porous structure, which has been easily combined with graphene sheets. The resulting nanocomposite powder displays a very homogeneous spatial distribution of Fe3–xO4 nanostructures at the surface of the graphene sheets. These original nanostructures and their strong interaction with the graphene sheets resulted in very small capacity fading upon Li+ ion intercalation. Reversible capacity, as high as 660 mAh/g, makes this material promising for anode in Li-ion batteries application

A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing

Purpose Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the “ClinVar low-hanging fruit” reanalysis, reasons for the failure of previous analyses, and lessons learned. Methods Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. Results We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). Conclusion The “ClinVar low-hanging fruit” analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock

- Aux temps du sans-abrisme. Enquêtes de terrain, problème public, Pichon P., Girola C., Jouve E. (dir.), Saint-Étienne, PUSE, 454 p.

International audienc

Wheat cultivars and natural‐based substances: Impacts on epidemiological parameters of yellow dwarf disease

International audienceFor many years, control methods against aphid-transmitted barley/cereal yellow dwarf viruses (B/CYDV) in cereal fields were mainly based on the use of neonicotinoid (NNI)-coated seeds. The ban of NNI by the EU in 2018 has reinforced the interest of the scientific community in the characterization of genetic resources and biological protections to find alternatives to chemicals for the management of B/CYDV. Eleven BYDV-susceptible wheat varieties were tested using a set of experimental procedures to evaluate their potential to alter parameters linked to the biology of aphids (Rhopalosiphum padi) and spread of virus (BYDV-PAV). Moreover, two natural-based substances (azadirachtin and mineral oil) were tested for their impact on the ability of aphids to survive, colonize and transmit the virus. Results showed that the 11 genotypes tested have a level of susceptibility to virus infection similar to the susceptible reference cv. Rubisko. However, when characterization focused on virus load, latency period and aphid fecundity, partial resistance phenotypes were observed for some cultivars. Furthermore, azadirachtin increased aphid mortality and decreased aphid fecundity. Thus, in addition to genes described for their ability to limit B/CYDV infections, the genetic backgrounds of B/CYDV-susceptible wheat cultivars and azadirachtin-based treatment should be considered for future management strategies against yellow dwarf disease

Fine Characterization of a Resistance Phenotype by Analyzing TuYV-Myzus persicae-Rapeseed Interactions

International audienceTurnip yellows virus (TuYV), transmitted by Myzus persicae, can be controlled in rapeseed fields by insecticide treatments. However, the recent ban of the neonicotinoids together with the description of pyrethrinoid-resistant aphids has weakened insecticide-based control methods available to farmers. Since the deployment of insecticides in the 1980s, few research efforts were made to breed for rapeseed cultivars resistant to aphid-borne viral diseases. Thus, only few rapeseed cultivars released in Europe were reported to be TuYV-resistant, and the resistance phenotype of these cultivars was poorly characterized. In this study, several epidemiological parameters (infection rate, latency period, etc.) associated to the TuYV-resistance of the cv. Architect were estimated. Results showed a partial resistance phenotype for plants inoculated at the 2-/4-leaves stages and a resistance phenotype for plants inoculated at a more advanced growing stage. Moreover, analysis of infected plants highlighted (i) a poor quality of infected cv. Architect as a source of virus for transmission and (ii) an extended latency period for infected plants. Thus, dynamics of virus spread in the field should to be slower for Architect compared to susceptible rapeseed cultivars, which should lead to the maintenance of a higher proportion of healthy plants in the field

L'agriculture néolithique à la loupe (série Past and Curious)

Il y a 11 000 ans, au Proche-Orient, se produit un changement fondamental dans l’histoire de l’humanité : la naissance de l'agriculture. En devenant agriculteurs, nos ancêtres du Néolithique ont profondément bouleversé leur mode de vie. Partons à la rencontre des premiers paysans du monde

Les sciences sociales et le sans-abrisme

International audienc

A fluorescent infectious clone of Turnip yellows virus to study the effect of aphid infestation on virus distribution in planta

BGPI : équipe 2Turnip yellows virus (TuYV) is a polerovirus (family Luteoviridae) restricted to phloem tissue and obligatorily transmitted by aphids in a circulative and non-propagative mode. This virus infects several plant species of economic importance. The icosahedral viral particles contain a single positive strand RNA genome. In order to track virus movement in plants and to measure the impact of aphids presence on virus distribution in plants, a GFP-tagged virus was engineered (TuYV-GFP). In this construct, the GFP sequence was inserted in a non-structural protein sequence involved, to some extent, in virus movement. The fluorescent signal is expected to label virus replicating cells. The TuYV-GFP sequence was introduced into a binary vector to inoculate several plant species by agro infiltration. TuYV-GFP was able to replicate and to move in A. thaliana, N.benthamiana and M. perfoliata. Accumulation of TuYV-GFP was however reduced when compared to the wild type virus. The impaired ability of the recombinant virus to reach efficiently non inoculated leaves is likely due to the insertion of the GFP sequence in the viral genome. The TuYVGFP genome was stable in N. benthamiana while it was subjected to partial deletions in A. thalianaand in M. perfoliata. Nevertheless, we observed fluorescent phloem cells in non-inoculated leaves of the three plant species. Importantly, fluorescent phloem cells were also observed after virus acquisition and inoculation by aphids, both in inoculated and non-inoculated leaves. This major breakthrough in the study of poleroviruses persistently transmitted by aphids will now be used to address whether the virus localisation in planta is affected following aphid infestation

Knockdown of cuticular transcripts in aphids: the ups and downs

BGPI : équipe 2Aphids are vectors for numerous viruses, most of them being transmitted in a non-circulative manner. Viruses bind to specific receptors located in the aphid stylets, from which they can be released to infect new hosts. The acrostyle is an organ located at the tip of maxillary stylets, which contains cuticular proteins, among which are the receptors of Cauliflower mosaic virus(CaMV) and potentially those of other non-circulative viruses1,2. Long term research to characterize these receptors has allowed us to identify one cuticular protein, Stylin-1, present in the acrostyle. Additionally this is the first protein specifically identified in insect stylets. Indirect evidence indicates a probable involvement of this protein in CaMV transmission. In order to validate the role of this candidate in non-circulative transmission we decided to set up silencing experiments to decrease the expression of the stylin-1 gene in the head of aphid, where the target organs – the retort glands which synthesize the stylets prior to the aphid moutling– are located. The amount of stylin-1 and the protein in the stylets should be negatively impacted upon treatment. Associated phenotypes, if any, will then be characterized. Even though RNAi technology has been successfully implemented in many insect species, silencing genes in aphids still remains challenging. Several approaches have thus been developed in our study on two different aphid species, Acyrthosiphon pisum and Myzus persicae, to maximize the chance of achieving our goal. Double stranded RNA (dsRNA)has been delivered by either injection into the insect abdomen, or by ingestion of artificial diets. Here we discuss our approaches and the problems we have faced, such as a high variability in the transcript levels measured by RT-qPCR and variable performance of housekeeping genes in control experiments. These issues can prevent accurate interpretation of the experiments. Several parameters such as the rearing of aphids, the choice of aphid larval stage, the concentration and mode of delivery of dsRNA molecules, the choice of housekeeping genes and negative controls, as well as methods of RTqPCR analyses by individual or pools have been optimized. An overview of the experiments conducted, which have led us to successfully reducing the accumulation of Stylin-1, in both aphid species will be presented along with the challenges overcome..