Interbedded history of Holocene tufa and alkaline peat formations in the Somme valley (France)

International audienceDuring the Holocene, concomitant formations of peat and calcareous tufas are recorded on chalky basins of north-west Europe (Belgium, Netherlands, Germany, Poland). Since the 19th century, geologists have recorded tufa-peat formations on the valley floor of the Middle Somme valley. Two systems of calcareous tufa have been identified in the midst of the peat deposits: 1) in dome-shaped tufas that wind through the valley and overhang the actual peaty valley floor by about three metres and 2) in lateral banks below the chalky cliffs. The interstratification with the peat deposits shows both simultaneous growth and different hydraulic conditions. The relationship between these sediments is still poorly documented, but offers possibilities for complementary palaeoenvironmental reconstruction.New fieldworks have provided a better understanding of these tufa-peat alternations. Stratigraphic surveys (tufa-peat sections and auger coring) of the Bourdon-Tirancourt sector and a GIS study of the valley floor were carried out, in order to characterise the geometry of the deposits and the environmental evolution during the Holocene. These surveys showed that the tufa domes developed in a paleochannel and at the bottom of dry valleys. Supplemented by a malacological study of a tufa dome in Bourdon and radiocarbon dating on peat, a first chronology of interstratification and environmental conditions is emerging to document the evolution of the water regime and aquifers of the valley floor during the Holocene.The development of tufas begins in the Preboreal period, according to the dating and several archaeological artefacts embedded in tufas. From 2300 BP the deposits became more silty and their formation was interrupted during the Iron Age. The peat preserved alongside the tufa dates from the Subboreal (around 3500 BP). Thus, the altitude of the top of tufas would indicate a more important peaty filling which has undergone a strong degradation (erosion, mineralization) and heights of water tables much higher than those observed nowadays

Heterozygous Mutant Mice Have a Subtle Locomotor Phenotype

Axon guidance receptors such as deleted in colorectal cancer (DCC) contribute to the normal formation of neural circuits, and their mutations can be associated with neural defects. In humans, heterozygous mutations in have been linked to congenital mirror movements, which are involuntary movements on one side of the body that mirror voluntary movements of the opposite side. In mice, obvious hopping phenotypes have been reported for bi-allelic mutations, while heterozygous mutants have not been closely examined. We hypothesized that a detailed characterization of heterozygous mice may reveal impaired corticospinal and spinal functions. Anterograde tracing of the motor cortex revealed a normally projecting corticospinal tract, intracortical microstimulation (ICMS) evoked normal contralateral motor responses, and behavioral tests showed normal skilled forelimb coordination. Gait analyses also showed a normal locomotor pattern and rhythm in adult mice during treadmill locomotion, except for a decreased occurrence of out-of-phase walk and an increased duty cycle of the stance phase at slow walking speed. Neonatal isolated spinal cords had normal left-right and flexor-extensor coupling, along with normal locomotor pattern and rhythm, except for an increase in the flexor-related motoneuronal output. Although mice do not exhibit any obvious bilateral impairments like those in humans, they exhibit subtle motor deficits during neonatal and adult locomotion

Targeted panel sequencing establishes the implication of planar cell polarity pathway and involves new candidate genes in neural tube defect disorders

International audienceNeural tube defect disorders are developmental diseases that originate from an incomplete closure of the neural tube during embryogenesis. Despite high prevalence-1 out of 3000 live births-their etiology is not yet established and both environmental and genetic factors have been proposed, with a heritability rate of about 60%. Studies in mouse models as well as in human have further suggested a multifactorial pattern of inheritance for neural tube defect disorders. Here, we report results obtained from clinical diagnosis and NGS analysis of a cohort composed of 52 patients. Using a candidate gene panel approach, we identified variants in known genes of planar cell polarity (PCP) pathway, although with higher prevalence than previously reported. Our study also reveals variants in novel genes such as FREM2 and DISP1. Altogether, these results confirm the implication of the PCP genes and involve the FRAS/FREM2 complex and Sonic Hedgehog signaling as novel components in the appearance of NTDs

Comparative constraint‐based modelling of fruit development across species highlights nitrogen metabolism in the growth‐defence trade‐off

Although primary metabolism is well conserved across species, it is useful to explore the specificity of its network to assess the extent to which some pathways may contribute to particular outcomes. Constraintbased metabolic modelling is an established framework for predicting metabolic fluxes and phenotypes and helps to explore how the plant metabolic network delivers specific outcomes from temporal series. After describing the main physiological traits during fruit development, we confirmed the correlations between fruit relative growth rate (RGR), protein content and time to maturity. Then a constraint-based method is applied to a panel of eight fruit species with a knowledge-based metabolic model of heterotrophic cells describing a generic metabolic network of primary metabolism. The metabolic fluxes are estimated by constraining the model using a large set of metabolites and compounds quantified throughout fruit development. Multivariate analyses showed a clear common pattern of flux distribution during fruit development with differences between fast-and slow-growing fruits. Only the latter fruits mobilise the tricarboxylic acid cycle in addition to glycolysis, leading to a higher rate of respiration. More surprisingly, to balance nitrogen, the model suggests, on the one hand, nitrogen uptake by nitrate reductase to support a high RGR at early stages of cucumber and, on the other hand, the accumulation of alkaloids during ripening of pepper and eggplant. Finally, building virtual fruits by combining 12 biomass compounds shows that the growthdefence trade-off is supported mainly by cell wall synthesis for fast-growing fruits and by total polyphenols accumulation for slow-growing fruits.Modélisation intégrative du fruit pour un système de sélection unifiéDéveloppement d'une infrastructure française distribuée pour la métabolomique dédiée à l'innovationCentre français de phénomique végétal

Erythematous maculopapular rash in monkeypox virus infection: A retrospective case series of 30 patients

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Genetic insights into biological mechanisms governing human ovarian ageing.

Reproductive longevity is essential for fertility and influences healthy ageing in women1,2, but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations3. The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease.Cambridge: Claudia Langenberg and Nicholas J Wareham are funded by the Medical Research Council (MC_UU_12015/1 and MC_UU_00006/1). Nicholas J Wareham is a NIHR Senior Investigator. Ken Ong, John Perry, Stasa Stankovic and Felix Day are supported by the Medical Research Council (Unit programmes: MC_UU_12015/2 and MC_UU_00006/2)