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A DNA Prime Immuno-Potentiates a Modified Live Vaccine against the Porcine Reproductive and Respiratory Syndrome Virus but Does Not Improve Heterologous Protection
No full textThe porcine reproductive and respiratory syndrome virus (PRRSV), an RNA virus inducing abortion in sows and respiratory disease in young pigs, is a leading infectious cause of economic losses in the swine industry. Modified live vaccines (MLVs) help in controlling the disease, but their efficacy is often compromised by the high genetic diversity of circulating viruses, leading to vaccine escape variants in the field. In this study, we hypothesized that a DNA prime with naked plasmids encoding PRRSV antigens containing conserved T-cell epitopes may improve the protection of MLV against a heterologous challenge. Plasmids were delivered with surface electroporation or needle-free jet injection and European strain-derived PRRSV antigens were targeted or not to the dendritic cell receptor XCR1. Compared to MLV-alone, the DNA-MLV prime- boost regimen slightly improved the IFNγ T-cell response, and substantially increased the antibody response against envelope motives and the nucleoprotein N. The XCR1-targeting of N significantly improved the anti-N specific antibody response. Despite this immuno-potentiation, the DNA-MLV regimen did not further decrease the serum viral load or the nasal viral shedding of the challenge strain over MLV-alone. Finally, the heterologous protection, achieved in absence of detectable effective neutralizing antibodies, was not correlated to the measured antibody or to the IFNγ T-cell response. Therefore, immune correlates of protection remain to be identified and represent an important gap of knowledge in PRRSV vaccinology. This study importantly shows that a naked DNA prime immuno-potentiates an MLV, more on the B than on the IFNγ T-cell response side, and has to be further improved to reach cross-protection
Pathogenicity and molecular‐phylogenetic analysis revealed a distinct position of the banana finger‐tip rot pathogen among the Burkholderia cenocepacia genomovars
No full textBanana (Musa spp.) is one of the most widely cultivated subtropical fruits around the globe. Banana cultivation has been extensively increased in southeastern Iran over the last two decades. Recently, banana fruits possessing rotten and blackened fingertip symptoms were observed in Sistan‐Baluchestan, Iran. Isolation and characterization of the causal agent showed that the pathogen belongs to the multifaceted bacterial species Burkholderia cenocepacia. Pathogenicity tests and host range assays showed that the strains were pathogenic on banana, as well as carrot, onion and potato. All the strains were resistant to 50 mg L−1 rifampicin and 200 mg L−1 copper sulphate. Phylogenetic analysis of 16S rRNA and recA gene sequences showed that the strains belong to two different genomovars of B. cenocepacia (III‐A and III‐B), which also include environmental and cystic fibrosis associated strains of the species. The results obtained from recA phylogeny were confirmed using multilocus sequence analysis (MLSA), although MLSA showed that the banana strains were clustered as a novel phylogroup among the members of both genomovars. Banana‐pathogenic B. cenocepacia strains isolated in Iran were different from the strains isolated in Taiwan, as the ‘B. cepacia epidemic strain marker’ reported in the Taiwanese strains was absent from Iranian strains. To the authors’ knowledge, this is the first MLSA‐based study on the banana‐pathogenic strains of B. cenocepacia. However, further in‐depth molecular studies are needed to decipher the relationships between the banana fingertip rot pathogen and the clinical strains of B. cenocepacia
The genome of cowpea (Vigna unguiculata [L.] Walp.)
No full textCowpea (Vigna unguiculata [ L.] Walp.) is a major crop for worldwide food and nutritional security, especially in sub-Saharan Africa, that is resilient to hot and drought-prone environments. A high-quality assembly of the single-haplotype inbred genome of cowpea IT97K-499-35 was developed by exploiting the synergies between single molecule real-time sequencing, optical and genetic mapping, and a novel assembly reconciliation algorithm. A total of 519 Mb is included in the assembled sequences. Nearly half of the assembled sequence is composed of repetitive elements, which are enriched within recombination-poor pericentromeric regions. A comparative analysis of these elements suggests that genome size differences between Vigna species are mainly attributable to changes in the amount of Gypsy retrotransposons. Conversely, genes are more abundant in more distal, high-recombination regions of the chromosomes; there appears to be more duplication of genes within the NBS-LRR and the SAUR-like auxin superfamilies compared to other warm-season legumes that have been sequenced. A surprising outcome of this study is the identification of a chromosomal inversion of 4.2 Mb among landraces and cultivars, which includes a gene that has been associated in other plants with interactions with the parasitic weed Striga gesnerioides. The genome sequence also facilitated the identification of a putative syntelog for multiple organ gigantism in legumes. A new numbering system has been adopted for cowpea chromosomes based on synteny with common bean (Phaseolus vulgaris)
Orchard Conditions and Fruiting Body Characteristics Drive the Microbiome of the Black Truffle Tuber aestivum
No full textTruffle fungi are well known for their enticing aromas partially emitted by microbes colonizing truffle fruiting bodies. The identity and diversity of these microbes remain poorly investigated, because few studies have determined truffle-associated bacterial communities while considering only a small number of fruiting bodies. Hence, the factors driving the assembly of truffle microbiomes are yet to be elucidated. Here we investigated the bacterial community structure of more than 50 fruiting bodies of the black truffle Tuber aestivum in one French and one Swiss orchard using 16S rRNA gene amplicon high-throughput sequencing. Bacterial communities from truffles collected in both orchards shared their main dominant taxa: while 60% of fruiting bodies were dominated by alpha-Proteobacteria, in some cases the beta-Proteobacteria or the Sphingobacteriia classes were the most abundant, suggesting that specific factors (i.e., truffle maturation and soil properties) shape differently truffle-associated microbiomes. We further attempted to assess the influence in truffle microbiome variation of factors related to collection season, truffle mating type, degree of maturation, and location within the truffle orchards. These factors had differential effects between the two truffle orchards, with season being the strongest predictor of community variation in the French orchard, and spatial location in the Swiss one. Surprisingly, genotype and fruiting body maturation did not have a significant effect on microbial community composition. In summary, our results show, regardless of the geographical location considered, the existence of heterogeneous bacterial communities within T. aestivum fruiting bodies that are dominated by three bacterial classes. They also indicate that factors shaping microbial communities within truffle fruiting bodies differ across local conditions
Effets de l’exposition maternelle aux nanoparticules d’or par ingestion, pendant la gestation, sur le développement foeto-placentaire et la fonction placentaire, dans un modèle lapin.
No full textVariabilité de l'expression vocale des porcelets lors de l'anticipation d'évènements positifs et négatifs
No full textL'utilisation des vocalisations en tant que marqueurs fiables et non invasifs des états émotionnels présente une opportunité de suivi et d'amélioration du bien-être animal en élevage. Le porc possède un grand répertoire vocal qui reflète son état interne, cependant l'expression vocale dans des contextes sociaux ou pseudo-sociaux
perçus positivement a été peu étudiée, notamment par la difficulté de générer expérimentalement de tels contextes. L'anticipation d'évènements positifs (récompense alimentaire par exemple) génère des émotions positives qui peuvent être plus intenses que l'évènement lui-même. Nous cherchons donc à quantifier la flexibilité
vocale exprimée lors de l'anticipation d'évènements sociaux positifs, de différentes valences et intensités. Un apprivoisement à l'humain a d'abord été réalisé sur la moitié des 60 porcelets testés. Au sein des loges d'élevage où les animaux ont été élevés par trois, des sessions d'interactions positives entre l'humain et les trois porcelets ont été menées, celles-ci étant connues pour susciter des réactions positives. Suite à cela un double conditionnement associatif a été réalisé. Nous avons, pour chaque cochon, diffusé un stimulus audiovisuel avant une réunion avec ses congénères de loge, et un autre stimulus audiovisuel à l'arrivée d'une expérimentatrice. Pour générer une phase d'anticipation de l'arrivée de l'évènement, la durée du stimulus a progressivement été
augmentée. La réunion avec des congénères a été considérée comme équitablement positive et de forte intensité pour les deux groupes. La réunion avec l'expérimentatrice a été considérée comme positive pour les animaux apprivoisés, et neutre ou négative pour les animaux non apprivoisés. Les caractéristiques spectro-temporelles des vocalisations ont été analysés de concert avec des données de comportement spatial pour classer les contextes selon leur valence et intensité et quantifier la flexibilité vocale exprimée. Les résultats préliminaires montrent une interaction statistique significative, à la fin du conditionnement entre le groupe expérimental (apprivoisement ou pas) et le type d'évènement anticipé (congénères ou expérimentatrice). Nous démontrons donc une flexibilité vocale à l'échelle individuelle. Cette étude est une première étape dans le décodage de la communication des émotions positives chez le porc
Effets de la nutrition et de l’obésité maternelle sur la fonction placentaire, la croissance, la santé métabolique et ostéoarticulaire du poulain
No full textCulicoides Latreille in the sun: faunistic inventory of Culicoides species (Diptera: Ceratopogonidae) in Mayotte (Comoros Archipelago, Indian Ocean)
No full textBackground: The south-west insular territories of the Indian Ocean have recently received attention concerning the diversity of arthropods of medical or veterinary interest. While a recent study highlighted the circulation of Culicoidesborne viruses, namely bluetongue and epizootic hemorrhagic disease, with clinical cases in Mayotte (comprising two islands, Petite-Terre and Grand-Terre), Comoros Archipelago, no data have been published concerning the species diversity of Culicoides present on the two islands.
Results: A total of 194,734 biting midges were collected in 18 sites, covering two collection sessions (April and
June) in Mayotte. Our study reports for the first time livestock-associated Culicoides species and recorded at least 17 described Afrotropical species and one undescribed species. The most abundant species during the April collection session were C. trifasciellus (84.1%), C. bolitinos (5.4%), C. enderleini (3.9%), C. leucostictus (3.3%) and C. rhizophorensis (2.1%). All other species including C. imicola represented less than 1% of the total collection. Abundance ranged between 126–78,842 females with a mean and median abundance of 14,338 and 5111 individuals/night/site, respectively. During the June collection, the abundance per night was low, ranging between 6–475 individuals. Despite low abundance, C. trifasciellus and C. bolitinos were still the most abundant species. Culicoides sp. #50 is recorded for the first time outside South Africa.
Conclusions: Our study reports for the first time the Culicoides species list for Mayotte, Comoros Archipelago, Indian Ocean. The low abundance and rare occurrence of C. imicola, which is usually considered the most abundant species in the Afrotropical region, is unexpected. The most abundant and frequent species is C. trifasciellus, which is not considered as a vector species so far, but its role needs further investigation. Further work is needed to describe Culicoides sp. #50 and to carry on faunistic investigations on the other islands of the archipelago as well as in neighboring countries
Population management using gene drive: molecular design, models of spread dynamics and assessment of ecological risks
No full textCRISPR gene drive has recently been proposed as a promising technology for population management, including in conservation genetics. The technique would consist in releasing genetically engineered individuals that are designed to rapidly propagate a desired mutation or transgene into wild populations. Potential applications in conservation biology include the control of invasive pest populations that threaten biodiversity (eradication and suppression drives), or the introduction of beneficial mutations in endangered populations (rescue drives). The propagation of a gene drive is affected by different factors that depend on the drive construct (e.g. its fitness effect and timing of expression) or on the target species (e.g. its mating system and population structure). We review potential applications of the different types of gene drives for conservation. We examine the challenges posed by the evolution of resistance to gene drives and review the various molecular and environmental risks associated with gene drives (e.g. propagation to non target populations or species and unintended detrimental ecosystem impacts). We provide some guidelines for future gene drive research and discuss ethical, biosafety and regulation issue