L'utilisation de l'aromathérapie dans les élevages français : état des lieux, efficacité et limites

En France, plusieurs facteurs incitent actuellement les éleveurs à modifier leurs pratiques de gestion de la santé animale. Les plans d'action EcoAntibio mis en place par le ministère de l'agriculture visent une diminution de l'utilisation des antibiotiques dans le secteur de l'élevage. En agriculture biologique, le cahier des charges limite l'utilisation de traitements vétérinaires conventionnels et sollicite les éleveurs à utiliser des traitements curatifs alternatifs. Les éleveurs conventionnels et biologiques s'intéressent donc de plus en plus à des médecines dites "alternatives". Parmi elles, l'aromathérapie se base sur l'utilisation des huiles essentielles pour leurs propriétés thérapeutiques. Dans les élevages français, cette pratique semble relativement développée dans certains secteurs, notamment en élevages bovins laitiers. Cette utilisation est d'autant plus marquée dans les élevages biologiques. Dans ces élevages laitiers, l'utilisation de l'aromathérapie se fait principalement dans le cas des mammites. L'efficacité de cette pratique sur les mammites n'est pas scientifiquement prouvée. Quelques essais ont été menés en collaboration avec des éleveurs pour essayer de mettre en évidence cette efficacité. Les résultats sont mitigés, avec une guérison clinique satisfaisante mais une guérison bactériologique peu concluante. Outre le manque de preuves en termes d'efficacité, l'aromathérapie est confrontée à un autre point de blocage : la règlementation. En élevage, l'utilisation thérapeutique de certaines substances végétales, dont un grand nombre d'huiles essentielles, n'entre pas dans le cadre de la médecine vétérinaire légale.In France, several factors currently encourage breeders to modify their animal health management practices. The EcoAntibio Action Plans launched by the Ministry of Agriculture aim to reduce use of antibiotics in livestock. In organic farming, the specification limits use of conventional veterinary treatments and ask breeders to use alternative curative treatments. Conventional and organic breeders are increasingly interested in so-called "alternative" medicines. Among them, aromatherapy is based on use of essential oils for their therapeutic properties. In French farms, this practice has developed in some sectors, particulary dairy cattle farms. This use is even more marked in organic farms. In these dairy farms, aromatherapy is mainly use for mastitis treatment. The effectiveness of this practice on mastitis is not scientifically proven. Some trials have been conduced in collaboration with breeders to highlight this effectiveness. The results are lukewarm, with a clinical cure but an inconclusive bacteriological cure. In addition to the lack of evidence in terms of efficiency, aromatherapy is facing antoher blocking point : regulation. In the breeding, the therapeutic use of certain substances, including many essential oils, does not fall within the scope of legal veterinary medicine

Utilisation d'isotope stable pour l'étude de la biodisponibilité orale de l'amitriptyline (application à l'influence d'un inhibiteur de la glycoprotéine-P)

POITIERS-BU Médecine pharmacie (861942103) / SudocSudocFranceF

Differential interactions of the beta-lactam cloxacillin with human renal organic anion transporters (OATs)

International audienceThe beta-lactam penicillin antibiotic cloxacillin (CLX) presents wide inter-individual pharmacokinetics variability. To better understand its molecular basis, the precise identification of the detoxifying actors involved in CLX disposition and elimination would be useful, notably with respect to renal secretion known to play a notable role in CLX elimination. The present study was consequently designed to analyze the interactions of CLX with the solute carrier transporters organic anion transporter (OAT) 1 and OAT3, implicated in tubular secretion through mediating drug entry at the basolateral pole of renal proximal cells. CLX was first shown to block OAT1 and OAT3 activity in cultured OAT-overexpressing HEK293 cells. Half maximal inhibitory concentration (IC50) value for OAT3 (13 mu m) was however much lower than that for OAT1 (560 mu m); clinical inhibition of OAT activity and drug-drug interactions may consequently be predicted for OAT3, but not OAT1. OAT3, unlike OAT1, was next shown to mediate CLX uptake in OAT-overexpressing HEK293 cells. Kinetic parameters for this OAT3-mediated transport of CLX (K-m = 10.7 mu m) were consistent with a possible in vivo saturation of this process for high CLX plasma concentrations. OAT3 is consequently likely to play a pivotal role in renal CLX secretion and consequently in total renal CLX elimination, owing to the low plasma unbound fraction of the antibiotic. OAT3 genetic polymorphisms as well as co-administered drugs inhibiting in vivo OAT3 activity may therefore be considered as potential sources of CLX pharmacokinetics variability

Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti-Legionella Agents

Legionella pneumophila, the causative agent of Legionnaires’ disease, is a waterborne bacterium mainly found in man-made water systems in close association with free-living amoebae and multispecies biofilms. Pseudomonas strains, originating from various environments including freshwater systems or isolated from hospitalized patients, were tested for their antagonistic activity towards L. pneumophila. A high amount of tested strains was thus found to be active. This antibacterial activity was correlated to the presence of tensioactive agents in culture supernatants. As Pseudomonas strains were known to produce biosurfactants, these compounds were specifically extracted and purified from active strains and further characterized using reverse-phase HPLC and mass spectrometry methods. Finally, all biosurfactants tested (lipopeptides and rhamnolipids) were found active and this activity was shown to be higher towards Legionella strains compared to various other bacteria. Therefore, described biosurfactants are potent anti-Legionella agents that could be used in the water treatment industry although tests are needed to evaluate how effective they would be under field conditions

Robustness analysis of metabolic predictions in algal microbial communities based on different annotation pipelines

International audienceAnimals, plants, and algae rely on symbiotic microorganisms for their development and functioning. Genome sequencing and genomic analyses of these microorganisms provide opportunities to construct metabolic networks and to analyze the metabolism of the symbiotic communities they constitute. Genome-scale metabolic network reconstructions rest on information gained from genome annotation. As there are multiple annotation pipelines available, the question arises to what extent differences in annotation pipelines impact outcomes of these analyses. Here, we compare five commonly used pipelines (Prokka, MaGe, IMG, DFAST, RAST) from predicted annotation features (coding sequences, Enzyme Commission numbers, hypothetical proteins) to the metabolic network-based analysis of symbiotic communities (biochemical reactions, producible compounds, and selection of minimal complementary bacterial communities). While Prokka and IMG produced the most extensive networks, RAST and DFAST networks produced the fewest false positives and the most connected networks with the fewest dead-end metabolites. Our results underline differences between the outputs of the tested pipelines at all examined levels, with small differences in the draft metabolic networks resulting in the selection of different microbial consortia to expand the metabolic capabilities of the algal host. However, the consortia generated yielded similar predicted producible compounds and could therefore be considered functionally interchangeable. This contrast between selected communities and community functions depending on the annotation pipeline needs to be taken into consideration when interpreting the results of metabolic complementarity analyses. In the future, experimental validation of bioinformatic predictions will likely be crucial to both evaluate and refine the pipelines and needs to be coupled with increased efforts to expand and improve annotations in reference databases

Inheritance of Secondary Metabolites and Gene Expression Related to Tomato Fruit Quality

International audienceFlavour and nutritional quality are important goals for tomato breeders. This study aimed to shed light upon transgressive behaviors for fruit metabolic content. We studied the metabolic contents of 44 volatile organic compounds (VOCs), 18 polyphenolics, together with transcriptome profiles in a factorial design comprising six parental lines and their 14 F1 hybrids (HF1) among which were five pairs of reciprocal HF1. After cluster analyses of the metabolome dataset and co-expression network construction of the transcriptome dataset, we characterized the mode of inheritance of each component. Both overall and per-cross mode of inheritance analyses revealed as many additive and non-additive modes of inheritance with few reciprocal effects. Up to 66% of metabolites displayed transgressions in a HF1 relative to parental values. Analysis of the modes of inheritance of metabolites revealed that: (i) transgressions were mostly of a single type whichever the cross and poorly correlated to the genetic distance between parental lines; (ii) modes of inheritance were scarcely consistent between the 14 crosses but metabolites belonging to the same cluster displayed similar modes of inheritance for a given cross. Integrating metabolome, transcriptome and modes of inheritance analyses suggested a few candidate genes that may drive important changes in fruit VOC contents

25 years of light-induced petrel groundings in Reunion Island: Retrospective analysis and predicted trends

Artificial lights are known to induce mass mortality of petrels. This study analyzes this phenomenon in Reunion Island, where four species are impacted: the endemic Barau’s petrel (Pterodroma baraui) and Mascarene petrel (Pseudobulweria aterrima), the tropical shearwater (Puffinus bailloni) and the wedge-tailed shearwater (Ardenna pacifica). 40,036 birds were found grounded between January 1996 and December 2021, most of which were fledglings. Spatial distribution of groundings matched with the distribution and intensity of light pollution. With a mark and recapture method, we estimated that at least 3.93 % of Barau's petrels fledglings are affected by light-induced groundings each year. This method was also used to estimate Barau’s Petrel population around 33,000 breeding pairs. Time series analyses showed strong positive trends of the number of groundings for all species, which were positively correlated with the intensity of light pollution. All species showed a seasonal increase in groundings coinciding with their fledging periods. Interannual variations of Barau's petrel and wedge-tailed shearwater groundings were explained by moon phase at their fledging peaks. We built statistical models to explain year-to-year changes in the number of groundings for each species, and used them to predict the number of groundings in the next decades. We predicted that up to 87,000 petrels may be found grounded from 2022 to 2050 if nothing is done to reduce light pollution. These results and predictions underline the urgent need to strengthen the rescue campaign and to implement strong light reduction measures

Insights into the potential for mutualistic and harmful host‐microbe interactions affecting brown alga freshwater acclimation

International audienceMicrobes can modify their hosts' stress tolerance, thus potentially enhancing their ecological range. An example of such interactions is Ectocarpus subulatus, one of the few freshwater-tolerant brown algae. This tolerance is partially due to its (un)cultivated microbiome. We investigated this phenomenon by modifying the microbiome of laboratory-grown E. subulatus using mild antibiotic treatments, which affected its ability to grow in low salinity. Low salinity acclimation of these algal-bacterial associations was then compared. Salinity significantly impacted bacterial and viral gene expression, albeit in different ways across algal-bacterial communities. In contrast, gene expression of the host and metabolite profiles were affected almost exclusively in the freshwater-intolerant algal-bacterial communities. We found no evidence of bacterial protein production that would directly improve algal stress tolerance. However, vitamin K synthesis is one possible bacterial service missing specifically in freshwater-intolerant cultures in low salinity. In this condition, we also observed a relative increase in bacterial transcriptomic activity and the induction of microbial genes involved in the biosynthesis of the autoinducer AI-1, a quorum-sensing regulator. This could have resulted in dysbiosis by causing a shift in bacterial behavior in the intolerant algal-bacterial community. Together, these results provide two promising hypotheses to be examined by future targeted experiments. Although they apply only to the specific study system, they offer an example of how bacteria may impact their host's stress response

Metabolic Complementarity Between a Brown Alga and Associated Cultivable Bacteria Provide Indications of Beneficial Interactions

Brown algae are key components of marine ecosystems and live in association with bacteria that are essential for their growth and development. Ectocarpus siliculosus is a genetic and genomic model for brown algae. Here we use this model to start disentangling the complex interactions that may occur between the algal host and its associated bacteria. We report the genome-sequencing of 10 alga-associated bacteria and the genome-based reconstruction of their metabolic networks. The predicted metabolic capacities were then used to identify metabolic complementarities between the algal host and the bacteria, highlighting a range of potentially beneficial metabolite exchanges between them. These putative exchanges allowed us to predict consortia consisting of a subset of these ten bacteria that would best complement the algal metabolism. Finally, co-culture experiments were set up with a subset of these consortia to monitor algal growth as well as the presence of key algal metabolites. Although we did not fully control but only modified bacterial communities in our experiments, our data demonstrated a significant increase in algal growth in cultures inoculated with the selected consortia. In several cases, we also detected, in algal extracts, the presence of key metabolites predicted to become producible via an exchange of metabolites between the alga and the microbiome. Thus, although further methodological developments will be necessary to better control and understand microbial interactions in Ectocarpus, our data suggest that metabolic complementarity is a good indicator of beneficial metabolite exchanges in the holobiont

Genome–Scale Metabolic Networks Shed Light on the Carotenoid Biosynthesis Pathway in the Brown Algae Saccharina japonica and Cladosiphon okamuranus

International audienceUnderstanding growth mechanisms in brown algae is a current scientific and economic challenge that can benefit from the modeling of their metabolic networks. The sequencing of the genomes of Saccharina japonica and Cladosiphon okamuranus has provided the necessary data for the reconstruction of Genome–Scale Metabolic Networks (GSMNs). The same in silico method deployed for the GSMN reconstruction of Ectocarpus siliculosus to investigate the metabolic capabilities of these two algae, was used. Integrating metabolic profiling data from the literature, we provided functional GSMNs composed of an average of 2230 metabolites and 3370 reactions. Based on these GSMNs and previously published work, we propose a model for the biosynthetic pathways of the main carotenoids in these two algae. We highlight, on the one hand, the reactions and enzymes that have been preserved through evolution and, on the other hand, the specificities related to brown algae. Our data further indicate that, if abscisic acid is produced by Saccharina japonica, its biosynthesis pathway seems to be different in its final steps from that described in land plants. Thus, our work illustrates the potential of GSMNs reconstructions for formalizing hypotheses that can be further tested using targeted biochemical approaches