Toxoplasma gondii in beef consumed in France: Regional variation in seroprevalence and parasite isolation

In France, the consumption of cattle and sheep meat appears to be a risk factor for infection of pregnant women with Toxoplasma gondii. Several nation-wide surveys in France have investigated the prevalence of T. gondii in sheep and pig meat, but little is known at present about the prevalence of the parasite in beef. The main objective of the present cross-sectional survey was to estimate the seroprevalence of T. gondii infection in beef consumed in France. A secondary objective was to attempt to isolate T. gondii from cattle tissues and to study the geographical and age variations of this seroprevalence. The overall estimate of seroprevalence of T. gondii in bovine carcasses (n = 2912), for a threshold of 1:6 was 17.38%. A strong age effect was observed (p lt 0.0001) with a seroprevalence of 5.34% for calves ( lt 8 months) and 23.12% for adults ( gt 8 months). Seroprevalence estimates given by area of birth and area of slaughtering for adults showed that the areas with the highest seroprevalence were not the same between these two variables. Only two strains, corresponding to genotype II, were isolated from heart samples, indicating that there is a limited risk of human infection with T. gondii, which needs to be correlated with the food habit of consuming raw or undercook (bleu or saignant) beef. However, new questions have emerged, especially concerning the isolation of parasites from beef and the precise role of bovines, generally described as poor hosts for T. gondii, in human infection

Anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs

Consumption of raw or undercooked meat containing Toxoplasma gondii tissue cysts is one of the main sources of infection for humans worldwide. Among the various species intended for human consumption, sheep appear to be a high risk for human infection. The present study focused on the detailed anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs using fresh and frozen samples of various pieces of meat, from a public health perspective. The first objective was to rank the edible parts intended for human consumption according to the detectable parasite burden by real-time PCR targeting the 529-bp repeated element. The second objective was to evaluate the impact of freezing by comparing the detection efficiency of the quantitative PCR between fresh and frozen tissues, as imports of lamb carcasses/cuts may arrive frozen or chilled. The highest estimated parasite loads were observed in skeletal muscles, and more particularly in edible portions such as quadriceps femoris muscle, intercostal muscles, deltoid muscle and diaphragm, with a significant difference in detectable parasite burden between fresh and frozen samples (p < 0.0001) or natural and experimental infection (p < 0.0001). Thoracic and pelvic limbs (3278–1048 parasites/g muscle) were ranked at the top of the list. Toxoplasma gondii DNA was detected in all the edible parts of lamb studied. These results suggest that lamb meat represents a risk for consumers. Further investigations are needed in order to confirm these differences in larger numbers of animals and in different breeds

Effect of fenfluramine on caloric intake and macronutrient selection in Lou/c rats during aging

Previous studies have shown a shift of preferences from carbohydrate to fat and a decrease in protein intake in self-selected Lou/c rats with advancing age. This study investigated a potential neurochemical mechanism underlying age-related modifications by evaluating the effects of fenfluramine (dl-F), a drug that enhances 5-HT release and blocks its re-uptake by presynaptic terminals, on macronutrient selection. The drug dl-F (1.5 and 3mg/kg s.c.) induces a dose-related hypophagia with the oldest animals being the most sensitive. The main decrease is in fat consumption with minor changes in carbohydrate and protein consumptions. Young, but not old animals, compensate during the day the nocturnal intake decrease induced by dl-F. The plasma concentration of dexfenfluramine (d-F) was higher as the rats aged. The icv administrations of dl-F induced a caloric intake decrease in the oldest groups and a differential effect on protein intake between old and young rats. Metergoline induced a partial reversion of dl-F effect on food intake but this effect was not age related. These data suggest a possible implication of serotoninergic system in modifications of food behavior during aging. However, further studies are needed

Zinc(II) modulates specifically amyloid formation and structure in model peptides

International audienceMetal ions such as zinc and copper can have dramatic effects on the aggregation kinetics of and the structures formed by several amyloidogenic peptides/proteins. Depending on the identity of the amyloidogenic peptide/protein and the conditions, Zn(II) and Cu(II) can promote or inhibit fibril formation, and in some cases these metal ions have opposite effects. To better understand this modulation of peptide aggregation by metal ions, the impact of Zn(II) binding to three amyloidogenic peptides (Aβ14-23, Aβ11-23, and Aβ11-28) on the formation and structure of amyloid-type fibrils was investigated. Zn(II) was able to accelerate fibril formation for all three peptides as measured by thioflavin T fluorescence and transmission electron microscopy. The effects of Zn(II) on Aβ11-23 and Aβ11-28 aggregation were very different compared with the effects of Cu(II), showing that these promoting effects were metal-specific. X-ray absorption spectroscopy suggested that the Zn(II) binding to Aβ11-23 and Aβ11-28 is very different from Cu(II) binding, but that the binding is similar in the case of Aβ14-23. A model is proposed in which the different coordination chemistry of Zn(II) compared with Cu(II) explains the metal-specific effect on aggregation and the difference between peptides Aβ14-23 and Aβ11-23/Aβ11-28

Structural study of selenium(IV) substitutions in calcite

In this work we present the results of a crystallographic study of synthetic calcite co-precipitated with selenium. We investigated both at a macroscopic and nanoscopic level, whether Se(IV) can be incorporated to bulk calcite by substitution at carbon sites. Neutron diffraction experiments, EXAFS spectroscopy and a theoretical modeling of the crystallographic structure using VASP are reported. We have found that the calcite unit cell volume obtained from the VASP simulations increases linearly with Se content in the structure. This allows estimating the Se content effectively incorporated into calcite based on volume measurements. Diffraction results are combined with VASP modeling to estimate a concentration of Se(IV) co-precipitated with calcite of 30–75 mmol/kg solid. EXAFS spectroscopy, in combination with our theoretical model of the local structure surrounding the Se atom, confirms the possibility of selenite ion substituting for carbonate anion in the calcite structure.Fil: Aurelio, Gabriela. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Fernández Martínez, Alejandro. Universite Grenoble Alpes; Francia. Institut Laue Langevin; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cuello, Gabriel Julio. Institut Laue Langevin; Francia. Universidad del País Vasco; España. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Roman Ross, Gabriela. Universidad de Girona; EspañaFil: Alliot, Isabelle. European Synchrotron Radiation Facility; FranciaFil: Charlet, Laurent. Universite Grenoble Alpes; Franci

Signes extra-oraux à rechercher face à des signes bucco-dentaires d’alerte de maladies d’origine génétique

International audienceThis article is aimed at defining guidelines for dental surgeons to manage patients with warning signs of rare genetic diseases. Anomalies of tooth development may occur as an isolated condition or in association with other symptoms in syndromes. In many cases, dental anomalies may be the first manifestations of a genetic disease. The dentist can contribute to the diagnosis, and hence to an early treatment of this syndrome. When one or more dental anomalies are found, practitioners should refer patients to a genetic clinic or a specialized reference center to diagnose genetic diseases. Therefore, we provide, for the first time, a table of extra-oral signs that dental surgeons can look for in patients exhibiting heritable dental developmental anomalies

Muscle proteome and transcriptome during aging of LOU/c/jall rats

National audienc

Effects of DEHP on the ecdysteroid pathway, sexual behavior and offspring of the moth Spodoptera littoralis

International audienc

Anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs

International audienceConsumption of raw or undercooked meat containing Toxoplasma gondii tissue cysts is one of the main sources of infection for humans worldwide. Among the various species intended for human consumption, sheep appear to be a high risk for human infection. The present study focused on the detailed anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs using fresh and frozen samples of various pieces of meat, from a public health perspective. The first objective was to rank the edible parts intended for human consumption according to the detectable parasite burden by real-time PCR targeting the 529-bp repeated element. The second objective was to evaluate the impact of freezing by comparing the detection efficiency of the quantitative PCR between fresh and frozen tissues, as imports of lamb carcasses/cuts may arrive frozen or chilled. The highest estimated parasite loads were observed in skeletal muscles, and more particularly in edible portions such as quadriceps femoris muscle, intercostal muscles, deltoid muscle and diaphragm, with a significant difference in detectable parasite burden between fresh and frozen samples ( p < 0.0001) or natural and experimental infection ( p < 0.0001). Thoracic and pelvic limbs (3278–1048 parasites/g muscle) were ranked at the top of the list. Toxoplasma gondii DNA was detected in all the edible parts of lamb studied. These results suggest that lamb meat represents a risk for consumers. Further investigations are needed in order to confirm these differences in larger numbers of animals and in different breeds.La consommation de viande crue ou insuffisamment cuite contenant des kystes tissulaires de Toxoplasma gondii est l’une des principales sources d’infection pour l’homme dans le monde. Parmi les différentes espèces destinées à la consommation humaine, le mouton apparaît à haut risque d’infection humaine. La présente étude s’est concentrée sur une distribution anatomique détaillée de Toxoplasma gondii chez des agneaux infectés naturellement et expérimentalement à l’aide d’échantillons frais et congelés de divers morceaux de viande, du point de vue de la santé publique. Classer les parties comestibles destinées à la consommation humaine, selon la charge parasitaire détectable par une PCR en temps réel ciblant l’élément répété de 529 pb était un premier objectif. Un second objectif était d’évaluer l’impact de la congélation en comparant l’efficacité de détection de la PCR quantitative entre les tissus frais et congelés, car les importations de carcasses/coupes d’agneau peuvent arriver congelées ou réfrigérées. Les charges parasitaires estimées les plus élevées ont été observées dans les muscles squelettiques et plus particulièrement dans les parties comestibles telles que le quadriceps fémoral, les muscles intercostaux, le deltoïde et le diaphragme avec une différence significative de charge parasitaire détectable entre les échantillons frais et congelés (p < 0,0001) ou l’infection naturelle et expérimentale (p < 0,0001). Les membres thoraciques et pelviens (3278 à 1048 parasites/g de muscle) ont été classés en tête de liste. L’ADN de T. gondii a été détecté dans toutes les parties comestibles étudiées de l’agneau. Ces résultats suggèrent que l’agneau représente un risque pour les consommateurs. Des investigations supplémentaires doivent être effectuées afin de confirmer les différences mentionnées ci-dessus chez plus d’animaux et dans différentes races

Effects of DEHP on post-embryonic development, nuclear receptor expression, metabolite and ecdysteroid concentrations of the moth Spodoptera littoralis

International audienceDi (2-ethylhexyl) phthalate (DEHP) is recognized in vertebrates as an Endocrine Disrupting Chemical (EDC). DEHP can alter steroid hormones production, development, reproduction and behavior in vertebrates. Only few studies investigated DEHP effects on insects. However, some recent studies on aquatic insects showed that DEHP could also act as an EDC by interfering with the signaling pathways of ecdysteroids, the main hormones involved in the control of insect post-embryonic development and physiology. The aim of the study was to investigate (1) the fate of DEHP within a terrestrial insect species by exposing larvae to food containing a wide range of DEHP concentrations and (2) the effects of this chemical on their post-embryonic development and metamorphosis, by using a multi-level approach. DEHP was shown to be present both in larvae and resulting stages, with higher concentrations in chrysalises and adults than in larvae. DEHP concentrations also decreased at the end of the last larval instar, suggesting the metabolic transformation or excretion of this chemical during this time. Only the two highest DEHP doses induced higher insect mortality, whereas low and intermediate concentrations increased larval food consumption without affecting body weight. Metabolic profiles showed that in control insects, the last three days before metamorphosis correspond to a metabolic transition, but with time-dependent changes in treated insects. Interestingly, DEHP treatments also alter both hemolymphatic ecdysteroid titers and expression levels of ecdysteroid response genes. These results confirm that DEHP can alter insect post-embryonic development and metamorphosis, by interfering with ecdysteroid pathways