L'écologie alimentaire d'Eucladoceros ctenoides : un outil pour suivre les variations environnementales régionales en Europe au Pléistocène inférieur

The early Pleistocene is represented by a succession of glacial-interglacial cycles character-ized by a general tendency towards global cooling, with increasing aridity and seasonality.The large deer Eucladoceros is found in abundance in Europe during this period of faunaldispersions. The dietary plasticity of Eucladoceros and how it can mirror early Pleistoceneclimatic variations will be explored here using Dental Microwear Texture Analysis. Thewide range of dental microwear textures for Eucladoceros reflects a low selectivity and highplasticity in its diet. It is an appropriate proxy to track vegetal resource availability. Oscil-lations were identified between a browsing and a grazing signal. This study proposes thata browsing signal is associated with a fossil assemblage deposited during an interglacialevent characterized by warmer temperatures and deciduous vegetation. A grazing signalmore likely indicates a glacial event with cooler temperatures and a developed herbaceous,bushy layer.Le Pléistocène inférieur correspond à une succession de cycles glaciaires-interglaciairescaractérisée par une tendance générale au refroidissement global, avec une aridité et unesaisonnalité croissantes. Le cervidé de grande taille Eucladoceros est abondant en Europedurant cette période de dispersions fauniques. Grâce à l'analyse de texture de la micro-usuredentaire, nous explorons la plasticité alimentaire d'Eucladoceros et la manière dont celle-ci reflète les variations climatiques du Pléistocène inférieur. La large gamme de texturesde micro-usure dentaire d'Eucladoceros reflète sa faible sélectivité et sa forte plasticité ali-mentaire. De fait, il constitue un outil approprié pour aborder la disponibilité en ressources végétales dans le milieu. Nous identifions des oscillations entre un signal brouteur et unsignal paisseur. Nous proposons qu'un signal brouteur soit associé à un assemblage fossiledéposé lors d'un évènement interglaciaire caractérisé par des températures plus chaudeset une végétation décidue, tandis qu'un signal paisseur correspondrait plutôt à un évène-ment glaciaire, avec des températures plus froides et la présence d?une strate herbacée etarbustive développée.This project was supported by the “Agence nationale dela recherche” (ANR TRIDENT: grant number: ANR-13-JSV7-0008-01; PI.: Gildas Merceron)

Using springbok (Antidorcas) dietary proxies to reconstruct inferred palaeovegetational changes over 2 million years in Southern Africa

The reconstruction of past vegetation and climatic conditions of the Cradle of Humankind, Gauteng Province, South Africa, has been approached using various proxies (such as micromammals, speleothems, faunal and floral presence and stable carbon isotopes). Elisabeth Vrba's seminal studies (1974; 1975) on the fossil record of this region indicated dramatic faunal turnover based on species extinction and speciation data. This turnover was thought to have been driven by increasing aridity and spreading grasslands. These reconstructions however, are continuously being refined and adapted in light of advancing techniques (such as dental microwear textural analysis) and terrestrial proxies, such as speleothems. However, more recent studies show varying proportions from wooded towards more grassland-dominated habitats, with the most common reconstruction being the heterogeneous ‘mosaic’ habitat. Here we re-evaluate the findings of a transition from woodland to grassland conditions in the fossil record from Member 4 Sterkfontein to Member 5 Sterkfontein and the deposits of Swartkrans. To approach the palaeovegetation changes through time via a different angle, we focus on the diet of the springbok (genus Antidorcas), represented throughout this temporal period from geological members dating from 2.8–0.8 Ma. We use detailed dietary methods (dental linear measurements, mesowear, microwear, and stable carbon isotope analysis) to explore past changes in diets of springbok that can be used to indicate the prevailing vegetation conditions. Our results presented here broadly agree with previous palaeoenvironmental reconstructions, in indicating increased grassland post ca 1.7 Ma, with some suggestion of more heterogeneous habitats for Swartkrans Member 2 (ca 1.65–1.07 Ma). We find that there is support for the implementation of a multi-disciplinary approach to produce more accurate and robust reconstructions of past diets and by extension, of palaeovegetation conditions, if the selected herbivore species is a mixed-feeder, like the springbok

Transformation around intruders in granular media

Sintering, glass melting and other industrially relevant processes turn batches of grains into homogeneous products. Such processes involve coupled chemical and physical transformations of the granular packing. For sake of simplicity, we study how local evolutions on grains (volume decreases for example) entail mechanical rearrangements in the overall pile. Inert bidisperse metallic disks are mixed and confined in a vertical 2D cell. At the bottom of this set-up, initial intruders (one or two) have been previously set and mechanically linked to a linear motorized jack. While we quasi-statically pull the intruder(s) downward out of the cell at constant speed and constant liberated surface, we tracked the surrounding granular packing. Events largely distributed both spatially and temporally occur around intruders. We focus on the influence of the distance between the intruders on the local dynamic of the packing. We compare the distribution of the size of the event and their frequency as function of the relative position of the intruder, as a function of their radius. We show that their influence decreases rapidly. At short distance the mechanical perturbation induced by one intruder can destabilize the packing around the other

3D Bioprinted Human Skeletal Muscle Constructs for Muscle Function Restoration

A bioengineered skeletal muscle tissue as an alternative for autologous tissue flaps, which mimics the structural and functional characteristics of the native tissue, is needed for reconstructive surgery. Rapid progress in the cell-based tissue engineering principle has enabled in vitro creation of cellularized muscle-like constructs; however, the current fabrication methods are still limited to build a three-dimensional (3D) muscle construct with a highly viable, organized cellular structure with the potential for a future human trial. Here, we applied 3D bioprinting strategy to fabricate an implantable, bioengineered skeletal muscle tissue composed of human primary muscle progenitor cells (hMPCs). The bioprinted skeletal muscle tissue showed a highly organized multi-layered muscle bundle made by viable, densely packed, and aligned myofiber-like structures. Our in vivo study presented that the bioprinted muscle constructs reached 82% of functional recovery in a rodent model of tibialis anterior (TA) muscle defect at 8 weeks of post-implantation. In addition, histological and immunohistological examinations indicated that the bioprinted muscle constructs were well integrated with host vascular and neural networks. We demonstrated the potential of the use of the 3D bioprinted skeletal muscle with a spatially organized structure that can reconstruct the extensive muscle defects

Applying FAIR Principles to plant phenotypic data management in GnpIS

GnpIS is a data repository for plant phenomics that stores whole field and greenhouse experimental data including environment measures. It allows long-term access to datasets following the FAIR principles: Findable, Accessible, Interoperable, and Reusable, by using a flexible and original approach. It is based on a generic and ontology driven data model and an innovative software architecture that uncouples data integration, storage, and querying. It takes advantage of international standards including the Crop Ontology, MIAPPE, and the Breeding API. GnpIS allows handling data for a wide range of species and experiment types, including multiannual perennial plants experimental network or annual plant trials with either raw data, i.e., direct measures, or computed traits. It also ensures the integration and the interoperability among phenotyping datasets and with genotyping data. This is achieved through a careful curation and annotation of the key resources conducted in close collaboration with the communities providing data. Our repository follows the Open Science data publication principles by ensuring citability of each dataset. Finally, GnpIS compliance with international standards enables its interoperability with other data repositories hence allowing data links between phenotype and other data types. GnpIS can therefore contribute to emerging international federations of information systems

Abrasive, Silica Phytoliths and the Evolution of Thick Molar Enamel in Primates, with Implications for the Diet of Paranthropus boisei

Background: Primates—including fossil species of apes and hominins—show variation in their degree of molar enamel thickness, a trait long thought to reflect a diet of hard or tough foods. The early hominins demonstrated molar enamel thickness of moderate to extreme degrees, which suggested to most researchers that they ate hard foods obtained on or near the ground, such as nuts, seeds, tubers, and roots. We propose an alternative hypothesis—that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species ’ degree of folivory. Methodology/Principal Findings: From a combination of dietary data and evidence for the levels of phytoliths in plant families in the literature, we calculated the percentage of plant foods rich in phytoliths in the diets of twelve extant primates with wide variation in their molar enamel thickness. Additional dietary data from the literature provided the percentage of each primate’s diet made up of plants and of leaves. A statistical analysis of these variables showed that the amount of abrasive silica phytoliths in the diets of our sample primates correlated positively with the thickness of their molar enamel, constrained by the amount of leaves in their diet (R 2 = 0.875; p,.0006). Conclusions/Significance: The need to resist abrasion from phytoliths appears to be a key selective force behind the evolution of thick molar enamel in primates. The extreme molar enamel thickness of the teeth of the East African homini

Palaeogenomics of Upper Palaeolithic to Neolithic European hunter-gatherers

Modern humans have populated Europe for more than 45,000 years1,2. Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period3. Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe4, but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants

Multiscale multifactorial approaches for engineering tendon substitutes

The physiology of tendons and the continuous strains experienced daily make tendons very prone to injury. Excessive and prolonged loading forces and aging also contribute to the onset and progression of tendon injuries, and conventional treatments have limited efficacy in restoring tendon biomechanics. Tissue engineering and regenerative medicine (TERM) approaches hold the promise to provide therapeutic solutions for injured or damaged tendons despite the challenging cues of tendon niche and the lack of tendon-specific factors to guide cellular responses and tackle regeneration. The roots of engineering tendon substitutes lay in multifactorial approaches from adequate stem cells sources and environmental stimuli to the construction of multiscale 3D scaffolding systems. To achieve such advanced tendon substitutes, incremental strategies have been pursued to more closely recreate the native tendon requirements providing structural as well as physical and chemical cues combined with biochemical and mechanical stimuli to instruct cell behavior in 3D architectures, pursuing mechanically competent constructs with adequate maturation before implantation.Authors acknowledge the project “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marinederived biomaterials and stem cells,” supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Authors acknowledge the H2020 Achilles Twinning Project No. 810850, and also the European Research Council CoG MagTendon No. 772817, and the FCT Project MagTT PTDC/CTM-CTM/ 29930/2017 (POCI-01-0145-FEDER-29930