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Phytophthora alni Infection Reinforces the Defense Reactions in Alnus glutinosa - Frankia Roots to the Detriment of Nodules

International audienceAlnus glutinosa, able to establish symbiosis with mutualistic bacteria of the genus Frankia, is one of the main species in European riparian environments, where it performs numerous biological and socio-economic functions. However, riparian ecosystems face a growing threat from Phytophthora alni, a highly aggressive waterborne pathogen causing severe dieback in A. glutinosa. To date, the tripartite interaction between the host plant, the symbiont Frankia and the pathogen remains unexplored but is critical for understanding how pathogen-induced stress influences the nodule molecular machinery and so on the host-symbiont metabolism. In the present study, we aimed to explore for the first time how P. alni affects the overall molecular processes of Alnus glutinosa – Frankia nodules, with a special focus on unraveling the spatial expression of defense mechanisms within these tissues. We conducted a laboratory experiment based on P. alni infection of young A. glutinosa seedlings nodulated with Frankia alni ACN14a, non-infected or infected with the pathogen P. alni. Multi-omics analyses were carried out on nodules (N) and associated roots (AR) of the same plant in order to underline the impact on the nodule molecular processes (i.e. N/AR markers) when the host plant is infected compared to non-infected plants. Our results revealed that P. alni infection modified the molecular nodule processes and induced reprograming of defense-related markers by a shift in associated roots to the detriment of nodules. These findings suggest that A. glutinosa reinforces locally its immune responses in roots but moderates this activation in nodule to preserve its Frankia symbiont

Mesoscale dynamics and transport in the North Brazil Current as revealed by the EUREC4A-OA experiment

International audienceThe North Brazil Current (NBC) rings are key features for interhemispheric water transport, facilitating exchange between the South Atlantic and North Atlantic Ocean. However, significant uncertainties persist regarding the total volume transported by these structures and the water masses they advect. In this study, we integrate high-resolution in situ observations from the EUREC4A-OA field experiment with satellite altimetry to address these knowledge gaps. Using a novel methodology, we estimate that surface NBC rings transport approximately 1.5 Sv, while subsurface eddies contribute between 0.4 and 9.7 Sv, underscoring their critical role in the regional total transport. Combined, these transports may significantly contribute to closing the Atlantic Meridional Overturning Circulation transport at low latitudes. Surface NBC rings predominantly advect Salinity Maximum Waters and fresh waters from the Amazon River, whereas subsurface NBC rings play a critical role in transporting Eastern South Atlantic Central Waters, Western South Atlantic Central Waters, and Antarctic Intermediate Waters northward. We estimate that the heat transport by surface and subsurface NBC rings is 5.8 and 0.3 TW, respectively, which is significantly lower than previous findings. Overall, these findings underscore the pivotal role of subsurface NBC rings as conduits for South Atlantic Waters across the Equator to the tropical North Atlantic. This study confirms the intricate dynamics of NBC rings and their essential role in interhemispheric water transport

Prévalence des maladies oculaires liées à l'exposition aux ultraviolets à Mayotte

Background: Mayotte is characterized by intense sun exposure throughout the year. Its intertropical geographic location exposes the population to high levels of ultraviolet radiation, which can have harmful effects not only on the skin but also on the eyes. This study aims to describe ocular lesions related to sun exposure in Mayotte.Method: Retrospective, multisite, and observational study based on anonymized patient records from october 2022 to november 2023. The prevalence of ocular diseases was expressed in absolute number and the rate as percentage. Variables significantly associated with the presence of the studied ocular disease (p ≤ 0,2) in the univariate model or deemed clinically relevant were included in a multivariate logistic regression model. Analyses were performed using R® software.Results: Among the 2,704 patients included, cataract had the highest prevalence of all observed ocular lesions, with n = 381 (14.1%), followed by dry eye syndrome n = 199 (7.4%), pterygium n = 170 (6.3%), photokeratitis n = 107 (4.0%), pinguecula n = 19 (0.7%), keratoconus n = 9 (0.3%), age-related macular degeneration (AMD) n = 6 (0.2%), and nevus/melanoma n = 5 (0.2%). High myopia had a prevalence of n = 46 (1.7%).Conclusion: This first study on the island of Mayotte highlights the impact of sun exposure on the eye. Raising awareness among health authorities to consider appropriate prevention measures appears necessary. The strength of this study lies in the near-exhaustiveness of ophtalmology consultations during the study period.Introduction : Mayotte est caractérisée par son exposition solaire intense tout au long de l’année. La situation géographique intertropicale expose sa population à des hauts niveaux de rayonnements ultraviolets qui peuvent entraîner des conséquences délétères sur la peau mais aussi sur les yeux. Cette étude a pour objectif de décrire les lésions oculaires liées à l’exposition solaire à Mayotte.Méthode : Étude rétrospective, multisite et observationnelle sur dossiers de patients anonymisés d’octobre 2022 à novembre 2023. La prévalence des maladies oculaires était exprimée en valeur absolue et son taux en pourcentage. Les variables significativement associées à la présence de la maladie oculaire étudiée (p ≤ 0,2) dans le modèle univarié ou cliniquement pertinentes ont été incluses dans un modèle de régression logistique multivarié. Les analyses ont été effectuées à l'aide du logiciel R®.Résultats : Sur les 2704 patients inclus de plus de 18 ans, l’âge moyen était de 48 ans (ET=16), la prévalence de la cataracte était la plus élevée des lésions oculaires observées n = 381 (14,1 %), suivie du syndrome sec n = 199 (7,4 %), du ptérygion n = 170 (6,3 %), de la photokératite n = 107 (4,0 %), de la pinguecula n = 19 (0,7 %), du kératocône n = 9 (0,3 %), de la DMLA n = 6 (0,2 %) et du naevus/mélanome n = 5 (0,2 %). La myopie forte a une prévalence de n = 46 (1,7 %).Conclusion : Cette première étude sur l'ile de Mayotte souligne l'impact du soleil sur l'œil. Une sensibilisation des instances sanitaires pour envisager des moyens de prévention adaptés semble nécessaire. La force de cette étude est d’avoir la quasi-exhaustivité des consultations en ophtalmologie sur cette période

Experimental Study of Magnetic Near-Field Microstrip Electronic Probe for PCB EMC Emission Measurement

International audienceAn experimental study on magnetic near-field (NF) scanning of printed circuit board (PCB) emission radiation is developed in this paper. The design and installation of the electromagnetic (EM) NF scanner is introduced. The test bed of magnetic NF emission in the microwave frequency range is described. The methodology of the microstrip magnetic NF probe is discussed. The probe calibration process was performed following the IEC 61967-1 NF scanning standard. The NF scanner functioning is tested with passive microstrip circuit square loop probe and device under test (DUT) PCB radiation in the test plan positioned at 1-mm above the ground plane. Based on the standard test with I-shape 50-Ω transmission line (TL), the calibration process of radiated magnetic field was validated by comparison between HFSS® simulation and experimentation in very wideband frequency from 0.1-GHz to 3-GHz. Then, a nonstandard TL based DUT was experimented. Accordingly, the cartographies of scanned magnetic NF at two different test frequencies, 2 GHz and 3 GHz, are discussed. The NF scanner is under development for targeting the EMC radiated emission of PCB dedicated to operate in 6G wireless communication.</div

Transcriptomic analyses in thirteen Tephritidae species provide molecular insights into the ecological driving force behind odorant receptor evolution

Source Agritrop Cirad (https://agritrop.cirad.fr/612486/)International audienceThe insect olfactory system has evolved while guiding species to specific mating partners, different food sources, and oviposition sites. How species repertoires of odorant receptors (ORs), responsible for the detection of volatile cues, have been shaped by ecologically driven forces remains poorly understood. Due to several host switches back and forth throughout their evolutionary history, fruit flies of the Tephritidae family (Diptera) show highly diverse host preferences, making them good models to address this question. For instance, a comparative analysis of genomic and transcriptomic resources on a large variety of fruit fly species could provide statistical conclusions. Here, we used a RNAseq approach to identify the OR repertoires of thirteen Tephritidae species with different host ranges, namely Bactrocera curvipennis, Bactrocera dorsalis, Bactrocera psidii, Bactrocera tryoni, Bactrocera umbrosa, Bactrocera zonata, Ceratitis capitata, Ceratitis catoirii, Ceratitis quilicii, Dacus ciliatus, Dacus demmerezi, Neoceratitis cyanescens, and Zeugodacus cucurbitae. Manual curation allowed us to annotate 60–80 OR transcripts per species, including the obligatory coreceptor Orco. In total, we reported 698 new OR sequences. Differential expression analyses between antennae and maxillary palps and between the two sexes, performed in three species, revealed some organ- and sex-biased OR expression. Moreover, after adjusting for phylogenetic distance, we found significant correlations between some characteristics of the OR repertoire and species host range: sequences and relative expression level of several ORs were more conserved in polyphagous than in oligophagous species and, in addition, other ORs were found specifically in polyphagous species. Our results provide molecular insights into the ecological driving forces behind Tephritidae OR evolution

A one health approach for integrated vector management monitoring and evaluation

International audienceThe French Agency for Food, Environmental and Occupational Health &amp; Safety (Anses) has set up a multidisciplinary working group (WG) to develop an innovative One Health approach for the monitoring and evaluation of an integrated vector management system (IVMS) on a territorial scale. Four existing evaluation guidelines and methods have been combined into a semi-quantitative evaluation approach that takes into account all the dimensions of an integrated process. We propose a set of 34 criteria divided into three sections (obj19ectives and management, implementation, integration) that correspond to the main functional components of an IVMS. Each criterion is assigned a score based on the results of a scoring questionnaire completed by the system's stakeholders, and two graphical outputs are generated using a specific combination of these scores. An overview of the system's performance is provided through a series of pie charts synthesizing the scores for each of the three sections and the corresponding eleven subsections. A radar chart further combines the results according to eight attributes chosen to characterize the qualities of the system. Our approach was tested for the invasive mosquito Aedes albopictus, a main vector of arboviruses, in two French territories with contrasting dengue epidemiology. This approach is intended to be generic and usable in all territories that are at risk of being affected by arboviruses, whether in tropical or temperate regions. Beyond a conventional assessment of the various components of an IVMS, our interdisciplinary and multisectoral approach aims to gain a better understanding of such a system in its environment, its overall functioning and its mechanisms for adapting to contextual change. It also aims to identify avenues for improvement as part of a continuous quality process, and to facilitate comparisons between territories and the cross-fertilization of knowledge between stakeholders