Comparative Embryonic Spatio-Temporal Expression Profile Map of the Xenopus P2X Receptor Family

International audienceP2X receptors are ATP-gated cations channels formed by the homo or hetero-trimeric association from the seven cloned subunits (P2X1-7). P2X receptors are widely distributed in different organs and cell types throughout the body including the nervous system and are involved in a large variety of physiological but also pathological processes in adult mammals. However, their expression and function during embryogenesis remain poorly understood. Here, we report the cloning and the comparative expression map establishment of the entire P2X subunit family in the clawed frog Xenopus. Orthologous sequences for 6 mammalian P2X subunits were identified in both X. laevis and X. tropicalis, but not for P2X3 subunit, suggesting a potential loss of this subunit in the Pipidae family. Three of these genes (p2rx1, p2rx2, and p2rx5) exist as homeologs in the pseudoallotetraploid X. laevis, making a total of 9 subunits in this species. Phylogenetic analyses demonstrate the high level of conservation of these receptors between amphibian and other vertebrate species. RT-PCR revealed that all subunits are expressed during the development although zygotic p2rx6 and p2rx7 transcripts are mainly detected at late organogenesis stages. Whole mount in situ hybridization shows that each subunit displays a specific spatio-temporal expression profile and that these subunits can therefore be grouped into two groups, based on their expression or not in the developing nervous system. Overlapping expression in the central and peripheral nervous system and in the sensory organs suggests potential heteromerization and/or redundant functions of P2X subunits in Xenopus embryos. The developmental expression of the p2rx subunit family during early phases of embryogenesis indicates that these subunits may have distinct roles during vertebrate development, especially embryonic neurogenesis

Feeding ecology of Southern Ocean seastars inferred from stable isotopes ratios

The Southern Ocean is currently subjected to strong and contrasted impacts of climate change. The Western Antarctic Peninsula is one of the most rapidly warming regions of the world, resulting in sea ice cover decreases. Increasing seawater temperature and sea ice cover reduction in Western Antarctic Peninsula and associated regions will likely impact food web functioning through temperature-related changes in consumer physiology, modifications of benthic community structure (e.g. expansion of exogenous species such as predatory crabs), modifications of benthic-pelagic coupling intensity or disruption of benthic production. Asteroids (Echinoderms) are an important group of southern benthos. This group also has a great trophic variability and is potentially more resistant than other organisms to temperature changes (Peck et al. 2008). Consequently, they will be likely impacted by modifications in food webs functioning rather by direct warming and investigating their trophic ecology is necessary to infer how climate change will impact them. In this context, the aim of this study is to use stable isotopes ratios of C, N and S to infer sea stars trophic ecology. 16 species of sea stars spanning 10 different families sampled in multiple and contrasted habitats across Subantarctic (South Georgia, South Sandwich Islands, Falkland Islands) and Antarctic (South Shetland Islands, South Orkney Islands, Western Antarctic Peninsula) locations. In total, tegument samples from 213 specimens was analysed. Diversity and plasticity of asteroid diet along Southern Ocean coasts were explored through isotopic niche parametrisation (e.g. niche width and overlap between species and/or populations; Jackson et al. 2011). The data will also be used in a larger scale research project on the trophic ecology of Antarctic sea stars. This project will notably compare trophic resources supporting asteroid communities in Western Antarctic Peninsula, where sea ice cover is decreasing, and in Terre Adélie, where sea ice cover is increasing (Parkinson & Cavalieri 2012). Ultimately, this project will help understanding which ecological processes determine how an animal group copes with environmental modifications linked to climate change

Preparation of gem-difluorinated retrohydroxamic-fosmidomycin

International audienceFrom several decades, some organophosphorus compounds specifically designed to alterbiological systems were introduced on market as agrochemicals (ie glyphosate and glufosinate asherbicides). Nevertheless, it becomes necessary to find new compounds in order to counter plantresistances already observed with glyphosate. Fosmidomicyn and its N-acetyl analogues FR-900098 were perceived as starting points for elaboration of new herbicide candidates, targetingthe second enzyme of the non-mevalonate pathway in plants, the 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DOXP reductoisomerase or DXR). It is expected that theenhancement of bioactivity compared to the parent compounds, might be reached by insertion oftwo fluorine atoms close to the phosphonate function. Indeed, the presence of both fluorineatoms could improve the lipophilicity, affect the pKa of the phosphonic acid function and theninduce better activities. Herein, the synthesis of gem-difluorinated analogues of retrohydroxamicfosmidomycin and FR-900098-ester is reported using a radical addition mediated by acobaloxime comple

Self-reported taste and smell alterations and the liking of oral nutritional supplements with sensory-adapted flavors in cancer patients receiving systemic antitumor treatment

Purpose Taste and smell alterations (TAs and SAs) are often reported by patients with cancer receiving systemic antitumor therapy and can negatively impact food intake and quality of life. This study aimed to examine the occurrence of TAs and SAs and investigate the impact of TAs on overall liking of oral nutritional supplements (ONS) with warming and cooling sensations. Methods Patients receiving systemic antitumor therapy completed a questionnaire on sensory alterations and evaluated overall liking of 5 prototype flavors of Nutridrink (R) Compact Protein (hot tropical ginger (HTG), hot mango (HM), cool red fruits (CRF), cool lemon (CL), and neutral (N)) on a 10-point scale via a sip test. Differences between patients with and without TAs were investigated using permutation analysis. Results Fifty patients with various cancer types and treatments were included. Thirty patients (60%) reported TAs and 13 (26%) experienced SAs. Three flavors were rated highly with a liking score > 6 (CRF 6.8 +/- 1.7; N 6.5 +/- 1.9; HTG 6.0 +/- 2.0). Larger variation in ONS liking scores was observed in patients with TAs with or without SAs (4.5-6.9 and 4.6-7.2, respectively) vs. patients without TAs (5.9-6.5). TAs were associated with increased liking of CRF (Delta = + 0.9) and N (Delta = + 1.0) flavors. Conclusions TAs and SAs are common in patients with cancer undergoing systemic antitumor therapy. Patients with TAs were more discriminant in liking of ONS flavors compared to patients without TAs, and sensory-adapted flavors appeared to be appreciated. The presence of TAs should be considered when developing or selecting ONS for patients with cancer

Trophic ecology of Southern Ocean sea stars inferred from stable isotopes ratios of C and N

The Southern Ocean undergoes strong and contrasted impacts of climate change. Increasing seawater temperature and sea ice cover reduction in Western Antarctic Peninsula and associated regions will likely impact food web structure and function. Sea stars (Echinoderms: Asteroidea) are an important group of the Southern Ocean benthos. They typically have highly variable feeding habits and are potentially more resistant than other organisms to temperature changes. Consequently, they will likely be impacted by modifications of the food web rather than by direct warming. Investigating their trophic ecology is therefore necessary to infer how climate change will impact them. In this context, the aim of this study was to use stable isotopes ratios of C, N and S to infer sea stars trophic ecology. During austral summers 2006 and 2009, sea stars were sampled in Subantarctic and Antarctic locations, with most of the samples coming from South Shetland Islands and South Georgia. The isotopic niche (proxy of the trophic niche) associated to each sea star population was explored through SIBER (Stable Isotope Bayesian Ellipses in R) metrics. Stable isotope ratios of sea stars were clearly different between South Shetland Islands and South Georgia. Sea stars of South Shetland Islands had smaller isotopic niches than sea stars of South Georgia. The overlap between the isotopic niches of sea star species was also important in South Shetland Islands, while isotopic niches of South Georgia were well separated. Difference of niche width and overlap between the two regions may be the result of different environmental conditions. In South Shetland Islands, sea star species may exploit a common benthic community relying on organic matter released during sea ice summer melting. In contrast, South Georgia is an oligotrophic environment with no sea ice. As resources are more limited, a higher trophic segregation between sea stars may appear to limit competition. Ultimately, this project highlighted the importance of sea ice in the trophic ecology of Antarctic sea stars. Our results suggest that future reduction of sea ice extent in Western Antarctica may have deleterious effect on sea star populations

L’Indice de Biodiversité Potentielle (IBP) dans les SLDF. Synthèse de 12 projets

Les 7 et 8 avril 2015 à Paris, le ministère de l'Ecologie a organisé, avec l'appui de la Fédération nationale des Communes forestières et en lien avec la Fédération des Parcs naturels régionaux, le séminaire de clôture de l'appel à projet sur « la prise en compte de la biodiversité dans les Stratégies locales de développement forestier (SLDF) ». Les SLDF désignent des outils de développement tels que les Chartes forestières de territoires (CFT) et les Plans de Développement de Massif (PDM). Animatrice du réseau des CFT, la Fédération nationale des Communes forestières a suivi l'appel à projet depuis son lancement en 2012, dans le cadre de la Stratégie nationale de la Biodiversité (SNB). En présence des ministères en charge de la biodiversité (MEDDE) et de la forêt (MAAF), ce séminaire a d'abord présenté un panorama des projets réalisés. Les objectifs: évaluer les résultats, les facteurs de réussites et les difficultés rencontrées, valoriser les expériences menées et en tirer des enseignements pour une diffusion des méthodes et des pratiques pour d'autres territoires. Ont ainsi témoigné des porteurs de démarches territoriales forêt-bois, des élus et des acteurs de l'environnement et de la recherche. La qualité des projets en termes de partenariat, de sensibilisation sur le terrain et de dialogue entre les différents acteurs a été unanimement soulignée. Les collectivités locales ont été identifiées comme cheffes de file de ces initiatives pionnières. L'accent a été mis la première journée sur les moyens de connaissance de la biodiversité et sa prise en compte dans la gestion forestière : production de données, d'informations et appropriation par les acteurs concernés. Mais aussi la diffusion de cette connaissance, notamment auprès des professionnels de la filière comme les Entrepreneurs de Travaux forestiers (ETF) et sa concrétisation dans les documents de gestion forestière: plans simples de gestion, documents d'aménagement. Pour poursuivre ces démarches, un lien plus fort doit être créé entre les territoires forestiers et la recherche qui dispose de méthodes et de connaissances approfondies, notamment sur les questions climatiques. Les retours d'expériences ont confirmé la nécessité d'intégrer la biodiversité dans des démarches plus transversales. Elle ne doit pas être "sacralisée" en forêt mais "socialisée", ont rappelé plusieurs intervenants. De plus, ces démarches doivent être incitatives plutôt que prescriptives et règlementaires. Il faut "donner envie" et même proposer des outils "ludiques", adaptés à un public large de propriétaires. Les projets ont aussi montré que la biodiversité apporte une vraie plus-value économique sur les territoires: résilience des forêts, respect des sols et qualité de l'eau, meilleure adaptation aux changements climatiques. Un bon exemple : les Projets Sylvicoles Territoriaux (PST) de la région Rhône-Alpes vise, au-delà de la production de bois d'œuvre, à optimiser les services écosystémiques rendus par la forêt et à décloisonner les approches : prise en compte dans les actions sylvicoles du carbone, de l'eau, de la biodiversité, des paysages ou encore des besoins économiques de la filière locale. La dernière journée était consacrée à la présentation des outils et des financements européens ainsi que les politiques publiques menées en France en faveur de la biodiversité. Les participants ont souligné que les actions pionnières menées sur le terrain nécessitent une animation importante et demande des moyens. Dans ce domaine, les Régions apparaissent comme les pilotes des futures politiques publiques de la biodiversité en cohérence attendue avec la politique nationale. Michaël Weber, vice-président de la Fédération des Parcs Naturels Régionaux et président de l'association des Communes forestières de Moselle, a ajouté que "les communes forestières, en tant que propriétaires de forêts et acteur indispensable des territoires, étaient au carrefour de ces préoccupations et force de concertation"