Camu-Camu Reduces Obesity and Improves Diabetic Profiles of Obese and Diabetic Mice : A Dose-Ranging Study

Overweight, obesity, and their comorbidities are currently considered a major public health concern. Today considerable efforts are still needed to develop efficient strategies able to attenuate the burden of these diseases. Nutritional interventions, some with plant extracts, present promising health benefits. In this study, we evaluated the action of Camu-Camu (Myrciaria dubia), an Amazonian fruit rich in polyphenols and vitamin C, on the prevention of obesity and associated disorders in mice and the abundance of Akkermansia muciniphila in both cecum and feces. Methods: We investigated the dose-response effects of Camu-Camu extract (CCE) in the context of high-fat-diet (HFD)-induced obesity. After 5 weeks of supplementation, we demonstrated that the two doses of CCE differently improved glucose and lipid homeostasis. The lowest CCE dose (62.5 mg/kg) preferentially decreased non-HDL cholesterol and free fatty acids (FFA) and increased the abundance of A. muciniphila without affecting liver metabolism, while only the highest dose of CCE (200 mg/kg) prevented excessive body weight gain, fat mass gain, and hepatic steatosis. Both doses decreased fasting hyperglycemia induced by HFD. In conclusion, the use of plant extracts, and particularly CCE, may represent an additional option in the support of weight management strategies and glucose homeostasis alteration by mechanisms likely independent from the modulation of A. muciniphila abundance.Peer reviewe

Dissolved inorganic carbon and alkalinity fluxes from coastal marine sediments: model estimates for different shelf environments and sensitivity to global change

We present a one-dimensional reactive transport model to estimate benthic fluxes of dissolved inorganic carbon (DIC) and alkalinity (<i>A</i><sub>T</sub>) from coastal marine sediments. The model incorporates the transport processes of sediment accumulation, molecular diffusion, bioturbation and bioirrigation, while the reactions included are the redox pathways of organic carbon oxidation, re-oxidation of reduced nitrogen, iron and sulfur compounds, pore water acid-base equilibria, and dissolution of particulate inorganic carbon (calcite, aragonite, and Mg-calcite). The coastal zone is divided into four environmental units with different particulate inorganic carbon (PIC) and particulate organic carbon (POC) fluxes: reefs, banks and bays, carbonate shelves and non-carbonate shelves. Model results are analyzed separately for each environment and then scaled up to the whole coastal ocean. The model-derived estimate for the present-day global coastal benthic DIC efflux is 126 Tmol yr<sup>−1</sup>, based on a global coastal reactive POC depositional flux of 117 Tmol yr<sup>−1</sup>. The POC decomposition leads to a carbonate dissolution from shallow marine sediments of 7 Tmol yr<sup>−1</sup> (on the order of 0.1 Pg C yr<sup>−1</sup>. Assuming complete re-oxidation of aqueous sulfide released from sediments, the effective net flux of alkalinity to the water column is 29 Teq. yr<sup>−1</sup>, primarily from PIC dissolution (46%) and ammonification (33%). Because our POC depositional flux falls in the high range of global values given in the literature, the reported DIC and alkalinity fluxes should be viewed as upper-bound estimates. Increasing coastal seawater DIC to what might be expected in year 2100 due to the uptake of anthropogenic CO<sub>2</sub> increases PIC dissolution by 2.3 Tmol yr<sup>−1</sup>and alkalinity efflux by 4.8 Teq. yr<sup>−1</sup>. Our reactive transport modeling approach not only yields global estimates of benthic DIC, alkalinity and nutrient fluxes under variable scenarios of ocean productivity and chemistry, but also provides insights into the underlying processes

Les environnements des Kerguelen : étude des amibes à thèque et des caractéristiques géochimiques

International audienceLes amibes à thèques sont des microorganismes cosmopolites dont la répartition est dépendante de l’hygrométrie, de la température et des facteurs biogéographiques. Une seule étude focalisée sur la diversité des amibes à thèque des Kerguelen a été réalisée en 1981. L’objectif est ici de cartographier les communautés d’amibes à thèques présentes et de comprendre les paramètres structurants (gradients de précipitations, variabilité des substrats). Pour extraire les amibes à thèque, 236 échantillons de bryophytes et de sol ont été prélevés sur l’archipel en novembre et décembre 2019 dans le cadre du programme de l’IPEV 1200 ENVIKER. L’observation des amibes à thèque réalisée à l’aide d’un microscope optique a permis de mettre en évidence une diversité spécifique importante tant dans le Loranchet que les sites proches de la base, comme l’Isthme bas. En parallèle, l’analyse géochimique des éléments traces et majeurs a pu être réalisée et comparée avec la distribution des amibes à thèque

Ségrégation urbaine et éducation : quels enjeux pour les politiques publiques ?

Compte rendu et analyses, Séminaire PUCA, 20 mars 2014, Paris La Défense

Ségrégation urbaine et éducation : quels enjeux pour les politiques publiques ?

Compte rendu et analyses, Séminaire PUCA, 20 mars 2014, Paris La Défense

Variation in the content of naphthoquinones in seeds and seedlings of Euclea natalensis

A correlation between plant growth and accumulation of naphthoquinones (shinanolone (1), 7-methyljuglone (2) and diospyrin (3)) was investigated in seeds and seedlings of Euclea natalensis A.DC. In this study, the seeds represented the first stage whereas the second seedling stage was defined as the stage, when the radicles were about 6 cm in length. The lengths of the seedlings at the third, fourth and fifth seedling stages were 9 cm, 12 cm and 16 cm respectively. Plant materials collected from the five seedling stages were separately extracted using chloroform and the naphthoquinones were then quantified by means of High Performance Liquid Chromatography (HPLC). Shinanolone (1), which was the only naphthoquinone detectible from seeds, accumulated at variable rates (P < 0.01) and no trend could be established between its synthesis and seedling growth. The content of shinanolone (1) ranged from 87.5 mg/kg in seeds (first stage) to a high mean value of 1047 mg/kg during the fourth seedling stage. A significant correlation (P < 0.01) was found between the mean concentrations of 7-methyljuglone (2) and seedling growth. 7-Methyljuglone (2) was quantified at a high mean level of 5003 mg/kg during the third seedling stage and was not detected from the seed samples. A positive correlation (P < 0.01) was established between the concentration of diospyrin (3) and seedling stages. Diospyrin (3) was detected at an elevated mean concentration of 6182 mg/kg during the fifth seedling stage, which was higher than the other quantified naphthoquinones

Local IFNα enhances the anti-tumoral efficacy of systemic anti-PD1 to prevent tumor relapse

International audienceBackground Tumor relapse constitutes a major challenge for anti-tumoral treatments, including immunotherapies. Indeed, most cancer-related deaths occur during the tumor relapse phase. Methods We designed a mouse model of tumor relapse in which mice transplanted with E7 + TC1 tumor cells received a single therapeutic vaccination of STxB-E7+IFNα. Unlike the complete regression observed after two vaccinations, such a treatment induced a transient shrinkage of the tumor mass, followed by a rapid tumor outgrowth. To prevent this relapse, we tested the efficacy of a local administration of IFNα together with a systemic therapy with anti-PD1 Ab. The immune response was analyzed during both the tumor regression and relapse phases. Results We show that, during the regression phase, tumors of mice treated with a single vaccination of STxB-E7 + IFNα harbor fewer activated CD8 T cells and monocytes than tumors doomed to fully regress after two vaccinations. In contrast, the systemic injection of an anti-PD1 Ab combined with the peri-tumoral injection of IFNα in this time frame promotes infiltration of activated CD8 T cells and myeloid cells, which, together, exert a high cytotoxicity in vitro against TC1 cells. Moreover, the IFNα and anti-PD1 Ab combination was found to be more efficient than IFNα or anti-PD1 used alone in preventing tumor relapse and was better able to prolong mice survival. Conclusions Together, these results indicate that the local increase of IFNα in combination with an anti-PD1 therapy is an effective way to promote efficient and durable innate and adaptive immune responses preventing tumor relapse