Molecular and Sensory Basis of a Food Related Two-State Behavior in C. elegans

Most animals display multiple behavioral states and control the time allocation to each of their activity phases depending on their environment. Here we develop a new quantitative method to analyze Caenorhabditis elegans behavioral states. We show that the dwelling and roaming two-state behavior of C. elegans is tightly controlled by the concentration of food in the environment of the animal. Sensory perception through the amphid neurons is necessary to extend roaming phases while internal metabolic perception of food nutritional value is needed to induce dwelling. Our analysis also shows that the proportion of time spent in each state is modulated by past nutritional experiences of the animal. This two-state behavior is regulated through serotonin as well as insulin and TGF-beta signaling pathways. We propose a model where food nutritional value is assessed through internal metabolic signaling. Biogenic amines signaling could allow the worm to adapt to fast changes in the environment when peptide transcriptional pathways may mediate slower adaptive changes

The missing <i>Myopus</i>:plugging the gaps in Late Pleistocene small mammal identification in western Europe with geometric morphometrics

15 pagesInternational audienceLemmus and Myopus are two lemming species with distinct habitat requirements but which show very similar dental morphologies. They are thus extremely difficult to distinguish from one another in the fossil record on the basis of their dental remains, leading to poor understanding of the palaeobiogeographical evolution of Myopus as well as inaccurate palaeoenvrionmental reconstructions. Currently, the presence of Myopus in the fossil register from the Pleistocene is still debated and no firm occurrence of this lemming in western Europe has yet been confirmed for the Late Pleistocene. In this paper, we used geometric morphometrics on modern material to establish morphological differences between Lemmus and Myopus teeth (first lower and third upper molars). Morphological data were then used to build a robust linear discriminant model able to confidently classify isolated teeth of these two genera, and finally, linear discriminant models were used on fossil remains of Lemmus/Myopus from two Late Pleistocene archaeological/palaeontological sites (Grotte des Gorges and Gully Cave). This study demonstrates, for the first time, the presence of Myopus schisticolor in west European Late Pleistocene sites between the end of Marine Isotope Stage 3 and the beginning of the Holocene, during climatic events that favoured the development of taiga forest of birch and pine in these regions

Utility of Quantitative 99mTc-MAA SPECT/CT for 90yttrium-Labelled Microsphere Treatment Planning: Calculating Vascularized Hepatic Volume and Dosimetric Approach

Objectives. The aim of this study was to assess the effectiveness of SPECT/CT for volume measurements and to report a case illustrating the major impact of SPECT/CT in calculating the vascularized liver volume and dosimetry prior to injecting radiolabelled yttrium-90 microspheres (Therasphere). Materials and Methods. This was a phantom study, involving volume measurements carried out by two operators using SPECT and SPECT/CT images. The percentage of error for each method was calculated, and interobserver reproducibility was evaluated. A treatment using Therasphere was planned in a patient with three hepatic arteries, and the quantitative analysis of SPECT/CT for this patient is provided. Results. SPECT/CT volume measurements proved to be accurate (mean error <6% for volumes ≥16 cm3) and reproductive (interobserver agreement = 0.9). In the case report, 99mTc-MAA SPECT/CT identified a large liver volume, not previously identified with angiography, which was shown to be vascularized after selective MAA injection into an arterial branch, resulting in a large modification in the activity of Therasphere used. Conclusions. MAA SPECT/CT is accurate for vascularized liver volume measurements, providing a valuable contribution to the therapeutic planning of patients with complex hepatic vascularization

Effect of cooling rate and aluminium addition on graphite growth during solidification and graphitization

Even using high inoculation levels, mottled structures are often obtained when casting Mg-treated cast irons in thin wall parts. For full graphitization of the cast components, this calls for a subsequent heat-treatment which is generally achieved in the austenite field. The aim of this work was investigating the impact of the process and the cooling rate on the graphite structure for two different casting conditions. The influence of the cooling rate on graphite degeneracy due to the presence of impurity was also investigated considering low-level additions of aluminium. Extensive metallographic investigation has been carried out from which it is concluded that the internal graphite structure is the same for the two studied cooling conditions. Accordingly, the growth mechanism of graphite should be the same when it precipitates from liquid, during eutectic reaction or else solid-state graphitization. Finally, microanalyses suggest magnesium and aluminium do not interact in the same way with graphite during its growth

Estrogen receptor-dependent modulation of dendritic cell biology of mice and women

Autoimmune and infectious diseases differentially affect women from men. Women tend to develop stronger immune responses and thus in general men are more susceptible to infectious diseases whereas women are more likely to develop autoimmune diseases. These differences could be in part attributable to the pro-inflammatory role of the female sex hormone estrogen on immunity and particularly on dendritic cells (DCs), a key subset of innate immune cells. For several years now, we have undertaken studies to understand how estrogens influence the biology of murine and human DCs. We and others have demonstrated that estradiol (E2) was required for the optimal in vitro differentiation of murine DCs and acquisition of their effector functions. These effects on DC biology were dependent on the activation of the estrogen receptor a (ERa). More recently, we focused our interest on plasmacytoid dendritic cells (pDCs). Indeed, this subset that produces large amounts of IFN-a/b in response to viral or endogenous nucleic acids through activation of their TLR-7 and TLR-9 show gender differences with enhanced IFN-a production by pDCs from women, compared to men. We could establish, in Human and in mice, that in vivo treatment with E2 enhanced the TLR-dependent production of IFNa by pDCs. In mice, we demonstrated that the amplifying effect of endogenous and exogenous estrogens is dependent on the intrinsic activation of ERα by hormone in the pDCs. To further characterize the mechanisms underlying this sex-based difference in pDC innate functions, we investigated the respective contribution of X chromosome dosage versus sex hormones using a humanized mouse model in which male or female NOD-SCID-ß2m-/- mice were transplanted with human progenitor cells (HPCs) purified from either male (XY) or female (XX) donors. We could show that cell-intrinsic ER-signaling and X chromosome complement both independently contribute to the enhanced TLR-7-mediated response of pDCs in women, which may account for the sex-based differences in autoimmune and infectious diseases. Altogether, our work demonstrates that estrogen-mediated activation of ER signaling is a key regulator of DC biology both in Human and in mouse

Rôle des lymphocytes cytotoxiques T CD8 et NK dans le contrôle des réponses T CD4 alloréactives

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Analyse des contours de la troisième molaire inférieure de boeuf : un moyen d'appréhender la variabilité morphologique du boeuf gallo-romain ?

10 pagesNational audienceÀ l'âge du Fer, en Europe occidentale, les animaux domestiques sont caractérisés par des dimensions réduites : ils sont petits et graciles. Or, à la période romaine, les animaux domestiques deviennent plus robustes et plus grands, et les morphologies se diversifient. Pour expliquer ce phénomène, les archéozoologues évoquent la diffusion de nouvelles pratiques d'élevage en Gaule, et / ou l'importation d'animaux italiens améliorés par le savoir-faire romain en matière d'élevage. De nouvelles méthodes apportent des éléments originaux pour appréhender cette " révolution zootechnique", contemporaine de la " romanisation " des Gaules. L'étude des variations de la taille et de la forme de la molaire 3 de boeuf, animal de grande valeur économique et symbolique durant l'Antiquité, a ainsi révélé une hétérogénéité des morphologies bovines en Gaule. Il n'existe donc pas une morphologie bovine gauloise versus une morphologie bovine romaine, et seule une approche interdisciplinaire, incluant entre autres des analyses isotopiques, permet d'associer une morphologie à une origine géographique

Sex hormone regulation of innate lymphoid cells

International audienceInnate lymphoid cell (ILC) subsets at barrier surfaces contribute to maintain tissue homeostasis and appropriate responses to infection. ILCs respond to environmental factors produced by non-hematopoietic cells within tissues, but also circulating cytokines or dietary compounds which allow them to adapt to organ milieu. Among these extrinsic signals, evidence is emerging that sex steroid hormones may act in a cell-intrinsic manner to regulate the development, maintenance in tissues and effector functions of specific subsets of ILCs. Understanding the nature and molecular mechanisms of sex steroid hormone actions on ILCs is important to unravel the cause of sexual disparity in human diseases and could lead to new drug development for the treatment of chronic inflammatory diseases or cancers. This review discusses the recent development in our understanding of the cell-intrinsic actions of sex steroid hormones on ILCs and their consequences on tissue-specific immunity with a particular focus on group 2 innate lymphoid cells and NK cells