Résumé
Climate change that we are facing is expected to influence multiple environmental processes, including weathering and
soil formation. While temperature and partial pressure of CO2 in the atmosphere are expected to directly influence
dissolution, in the soils their effect is compounded by plant response to environmental change. In order to evaluate effect
of temperature and CO on rock dissolution, plant growth and nutrient uptake, we conducted mesocosm experiments
2where we exposed three different plants grown in unweathered basalt tephra, as well as unplanted but not sterilized
control, to following conditions: two different CO2 levels, 400 ppm and 800 ppm, and two climate regimes, with ambient
(21-25°C) and elevated (25-30°C) temperatures. Tight control on the environmental variables was possible by conducting
experiments at the ECOTRON Ile-De-France facility, France. Studied plants included velvet mesquite (Prosopis velutina),
green spangletop (Leptochloa dubia), and alfalfa (Medicago sativa). Both mesquite and alfalfa were inoculated with the
nitrogen-fixing bacteria. Pore water solution and leachates were collected at set intervals and analyzed to determine pH,
conductivity, and concentrations of C, N, and lithogenic elements. At the end of the experiment, all plant biomass was
collected, dried, weighed, and subsamples digested to determine nutrient uptake by the plants. Soils were also analyzed
for changes in organic and inorganic C and total N content. We observed significant increase in solution concentrations for
several lithogenic elements, such as Si, Mg, and P with increase in temperature. Concentrations in the biomass were also
increased for many elements. However, biomass production was smaller at elevated temperature for alfalfa, resulting in
less treatment difference when total uptake by the plants was compared. Fewer effects of elevated CO were measured;
2among them was greater carbonate precipitation in the soil. This study indicates that climate change would affect both abiotic and biotic components of soil formation.
Auteurs, date et publication :
Auteurs K. Dontsova , Sabrina Juarez , E. Villasenor , J.-F. Le Galliard , Simon Chollet , Mathieu Llavata , Florent Massol , E. Hunt , Pierre Barré , D. Daval , A. Gelabert , G. Barron-Gafford , J. van Haren , P. Troch , R. Ferriere
Date : 2025
Catégorie(s)
#⛔ No DOI found #CNRS #Ecotron IleDeFrance #ENSAuteurs, date et publication :
Auteurs Béatrice Allard , Michaël Danger , Loïc Ten-Hage , Gérard Lacroix
Publication : Aquatic Sciences
Date : 2025
Volume : 73
Issue : 1
Pages : 113-126
Catégorie(s)
#CNRS #ENS #PLANAQUARésumé
Understanding the external stimuli and natural contexts that elicit complex behaviours, such as parental care, is key in linking behavioural mechanisms to their real-life function. Poison frogs provide obligate parental care by shuttling their tadpoles from terrestrial clutches to aquatic nurseries, but little is known about the proximate mechanisms that control these behaviours. In this study, we used Allobates femoralis, a poison frog with predominantly male parental care, to investigate whether tadpole transport can be induced in both sexes by transferring unrelated tadpoles to the backs of adults in the field. Specifically, we asked whether the presence of tadpoles on an adult’s back can override the decisionmaking rules preceding tadpole pick-up and induce the recall of spatial memory necessary for finding tadpole deposition sites. We used telemetry to facilitate accurate tracking of individual frogs and spatial analysis to compare movement trajectories. All tested individuals transported their foster-tadpoles to water pools outside their home area. Contrary to our expectation, we found no sex difference in the likelihood to transport or in the spatial accuracy of finding tadpole deposition sites. We reveal that a stereotypical cascade of parental behaviours that naturally involves sex-specific offspring recognition strategies and the use of spatial memory can be manipulated by experimental placement of unrelated tadpoles on adult frogs. As individuals remained inside their home area when only the jelly from tadpole-containing clutches was brushed on the back, we speculate that tactile rather than chemical stimuli trigger these parental behaviours.
Auteurs, date et publication :
Auteurs Andrius Pašukonis , Kristina Barbara Beck , Marie-Therese Fischer , Steffen Weinlein , Susanne Stückler , Eva Ringler
Publication : The Journal of Experimental Biology
Date : 2017
Pages : jeb.165126
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Early nutrition plays a dominant role in infant development and health. It is now understood that the infant diet impacts the gut microbiota and its relationship with gut function and brain development. However, its impact on the microbiota-gut-brain axis has not been studied in an integrative way. The objective here was to evaluate the effects of human milk (HM) or cow’s milk based infant formula (IF) on the relationships between gut microbiota and the collective host intestinal-brain axis. Eighteen 10-day-old Yucatan mini-piglets were fed with HM or IF. Intestinal and fecal microbiota composition, intestinal phenotypic parameters, and the expression of genes involved in several gut and brain functions were determined. Unidimensional analyses were performed, followed by multifactorial analyses to evaluate the relationships among all the variables across the microbiota-gut-brain axis. Compared to IF, HM decreased the α-diversity of colonic and fecal microbiota and modified their composition. Piglets fed HM had a significantly higher ileal and colonic paracellular permeability assessed by
ex vivo
analysis, a lower expression of genes encoding tight junction proteins, and a higher expression of genes encoding pro-inflammatory and anti-inflammatory immune activity. In addition, the expression of genes involved in endocrine function, tryptophan metabolism and nutrient transport was modified mostly in the colon. These diet-induced intestinal modifications were associated with changes in the brain tissue expression of genes encoding the blood-brain barrier, endocrine function and short chain fatty acid receptors, mostly in hypothalamic and striatal areas. The integrative approach underlined specific groups of bacteria (Veillonellaceae, Enterobacteriaceae, Lachnospiraceae, Rikenellaceae, and Prevotellaceae) associated with changes in the gut-brain axis. There is a clear influence of the infant diet, even over a short dietary intervention period, on establishment of the microbiota-gut-brain axis.
Auteurs, date et publication :
Auteurs Elise Charton , Alexandre Bourgeois , Amandine Bellanger , Yann Le-Gouar , Patrice Dahirel , Véronique Romé , Gwenaelle Randuineau , Armelle Cahu , Paul J. Moughan , Carlos A. Montoya , Sophie Blat , Didier Dupont , Amélie Deglaire , Isabelle Le Huërou-Luron
Publication : Frontiers in Nutrition
Date : 2022
Volume : 9
Pages : 976042
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Intact tropical rainforests have been exposed to severe droughts in recent decades, which may threaten their integrity, their ability to sequester carbon, and their capacity to provide shelter for biodiversity. However, their response to droughts remains uncertain due to limited high-quality, long-term observations covering extensive areas. Here, we examined how the upper canopy of intact tropical rainforests has responded to drought events globally and during the past 3 decades. By developing a long pantropical time series (1992 to 2018) of monthly radar satellite observations, we show that repeated droughts caused a sustained decline in radar signal in 93%, 84%, and 88% of intact tropical rainforests in the Americas, Africa, and Asia, respectively. Sudden decreases in radar signal were detected around the 1997–1998, 2005, 2010, and 2015 droughts in tropical Americas; 1999–2000, 2004–2005, 2010–2011, and 2015 droughts in tropical Africa; and 1997–1998, 2006, and 2015 droughts in tropical Asia. Rainforests showed similar low resistance (the ability to maintain predrought condition when drought occurs) to severe droughts across continents, but American rainforests consistently showed the lowest resilience (the ability to return to predrought condition after the drought event). Moreover, while the resistance of intact tropical rainforests to drought is decreasing, albeit weakly in tropical Africa and Asia, forest resilience has not increased significantly. Our results therefore suggest the capacity of intact rainforests to withstand future droughts is limited. This has negative implications for climate change mitigation through forest-based climate solutions and the associated pledges made by countries under the Paris Agreement.
Auteurs, date et publication :
Auteurs Shengli Tao , Jérôme Chave , Pierre-Louis Frison , Thuy Le Toan , Philippe Ciais , Jingyun Fang , Jean-Pierre Wigneron , Maurizio Santoro , Hui Yang , Xiaojun Li , Nicolas Labrière , Sassan Saatchi
Publication : Proceedings of the National Academy of Sciences
Date : 2022
Volume : 119
Issue : 37
Pages : e2116626119
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Human activities are enriching many of Earth’s ecosystems with biologically limiting mineral nutrients such as nitrogen (N) and phosphorus (P). In grasslands, this enrichment generally reduces plant diversity and increases productivity. The widely demonstrated positive effect of diversity on productivity suggests a potential negative feedback, whereby nutrient-induced declines in diversity reduce the initial gains in productivity arising from nutrient enrichment. In addition, plant productivity and diversity can be inhibited by accumulations of dead biomass, which may be altered by nutrient enrichment. Over longer timeframes, nutrient addition may increase soil fertility by increasing soil organic matter and nutrient pools. We examined the effects of 5-11 years of nutrient addition at 47 grasslands in twelve countries. Nutrient enrichment increased aboveground live biomass and reduced plant diversity at nearly all sites, and these effects became stronger over time. We did not find evidence that nutrient-induced losses of diversity reduced the positive effects of nutrients on biomass, however nutrient effects on live biomass increased more slowly at sites where litter was also increasing, regardless of plant diversity. This work suggests that short-term experiments may underestimate the long-term nutrient enrichment effects on global, grassland ecosystems.
Auteurs, date et publication :
Auteurs Eric W. Seabloom , Peter B. Adler , Juan Alberti , Lori Biederman , Yvonne M. Buckley , Marc W. Cadotte , Scott L. Collins , Laura Dee , Philip A. Fay , Jennifer Firn , Nicole Hagenah , W. Stanley Harpole , Yann Hautier , Andy Hector , Sarah E. Hobbie , Forest Isbell , Johannes M. H. Knops , Kimberly J. Komatsu , Ramesh Laungani , Andrew MacDougall
Publication : Ecology
Date : 2025
Volume : n/a
Issue : n/a
Catégorie(s)
#CEREEP #CNRS #ENSAuteurs, date et publication :
Auteurs Ethan E. Butler , Kirk R. Wythers , Habacuc Flores‐Moreno , Daniel M. Ricciuto , Abhirup Datta , Arindam Banerjee , Owen K. Atkin , Jens Kattge , Peter E. Thornton , Madhur Anand , Sabina Burrascano , Chaeho Byun , J.H.C. Cornelissen , Estelle Forey , Steven Jansen , Koen Kramer , Vanessa Minden , Peter B. Reich
Publication : Journal of Geophysical Research: Biogeosciences
Date : 2025
Catégorie(s)
#CIRAD #CNRS #FORET Paracou #FORET PuechabonRésumé
Clear cell renal cell carcinoma (ccRCC) is an aggressive tumor that is characterized in most cases by inactivation of the tumor suppressor gene VHL. The VHL/HIF/VEGF pathway thus plays a major role in angiogenesis and is currently targeted by anti-angiogenic therapy. The emergence of resistance is leading to the use of targeted immunotherapy against immune checkpoint PD1/PDL1 that restores antitumor immune response. The correlation between VHL status and PD-L1 expression has been little investigated. In this study, we retrospectively reviewed 98 consecutive cases of ccRCC and correlated PD-L1 expression by immunohistochemistry (IHC) with clinical data (up to 10-year follow-up), pathological criteria, VEGF, PAR-3, CAIX and PD-1 expressions by IHC and complete VHL status (deletion, mutation and promoter hypermethylation). PD-L1 expression was observed in 69 ccRCC (70.4%) and the corresponding patients had a worse prognosis, with a median specific survival of 52 months (p = 0.03). PD-L1 expression was significantly associated with poor prognostic factors such as a higher ISUP nucleolar grade (p = 0.01), metastases at diagnosis (p = 0.01), a sarcomatoid component (p = 0.04), overexpression of VEGF (p = 0.006), and cytoplasmic PAR-3 expression (p = 0.01). PD-L1 expression was also associated with dense PD-1 expression (p = 0.007) and with ccRCC with 0 or 1 alteration(s) (non-inactivated VHL tumors; p = 0.007) that remained significant after multivariate analysis (p = 0.004 and p = 0.024, respectively). Interestingly, all wild-type VHL tumors (no VHL gene alteration, 11.2%) expressed PD-L1. In this study, we found PD-L1 expression to be associated with noninactivated VHL tumors and in particular wild-type VHL ccRCC, which may benefit from therapies inhibiting PD-L1/PD-1.
Auteurs, date et publication :
Auteurs Solène-Florence Kammerer-Jacquet , Laurence Crouzet , Angélique Brunot , Julien Dagher , Adélaïde Pladys , Julien Edeline , Brigitte Laguerre , Benoit Peyronnet , Romain Mathieu , Grégory Verhoest , Jean-Jacques Patard , Alexandra Lespagnol , Jean Mosser , Marc Denis , Yosra Messai , Sophie Gad-Lapiteau , Salem Chouaib , Marc-Antoine Belaud-Rotureau , Karim Bensalah , Nathalie Rioux-Leclercq
Publication : International Journal of Cancer
Date : 2017
Volume : 140
Issue : 1
Pages : 142-148
Catégorie(s)
#CNRS #EcoGenO #Université de RennesAuteurs, date et publication :
Auteurs Nicolas Labriere , Shengli Tao , Jerome Chave , Klaus Scipal , Thuy Le Toan , Katharine Abernethy , Alfonso Alonso , Nicolas Barbier , Pulcherie Bissiengou , Tania Casal , Stuart J. Davies , Antonio Ferraz , Bruno Herault , Gaelle Jaouen , Kathryn J. Jeffery , David Kenfack , Lisa Korte , Simon L. Lewis , Yadvinder Malhi , Herve R. Memiaghe
Publication : IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date : 2025
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesRésumé
Alpine plants like Soldanella alpina L. are subjected to high PAR and high UV radiation. Among the important photoprotective mechanisms that prevent photoinhibition under such conditions, passive optical barriers such as UV-absorbing compounds were investigated. In this study, temporal and spatial patterns of epidermal UV-A absorbance for S. alpina leaves were investigated with a combination of absorbance measurements at 375 nm and imaging methods. UV-A absorbance was highest in plants acclimated to full sunlight and was markedly stable during the leaves’ lifetime. UV-A absorbance was correlated with leaf structure (leaf mass per area ratio, density of epidermal cells and stomata) and biochemical features such as chlorophyll and carotenoid content and ratio, which are characteristics of light acclimation. UV-A-absorbing compounds were mainly localised in the epidermal vacuoles and trichomes. Leaves with low UV-A absorbance were significantly more photosensitive than leaves with high UV-A absorbance. However, the epidermal UV-A absorbance increased in low-absorbance leaves under full sunlight even in the absence of UV radiation. Results suggest that high epidermal UV-A absorbance protects S. alpina leaves from photoinactivation, which is especially important after snowmelt, when plants are suddenly exposed to full sunlight.
Auteurs, date et publication :
Auteurs Constance Laureau , Sylvie Meyer , Xavier Baudin , Christophe Huignard , Peter Streb
Publication : Functional Plant Biology
Date : 2025
Volume : 42
Issue : 7
Pages : 599