Murviel-lès-Montpellier, France
Murviel-lès-Montpellier, France

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Doucoure S.,Universities of Montpellier 1 and 2 | Cornelie S.,Universities of Montpellier 1 and 2 | Patramool S.,Universities of Montpellier 1 and 2 | Mouchet F.,Universities of Montpellier 1 and 2 | And 9 more authors.
Insect Molecular Biology | Year: 2013

Study of the human antibody (Ab) response to Aedes salivary proteins can provide new biomarkers to evaluate human exposure to vector bites. The identification of genus- and/or species-specific proteins is necessary to improve the accuracy of biomarkers. We analysed Aedes albopictus immunogenic salivary proteins by 2D immunoproteomic technology and compared the profiles according to human individual exposure to Ae. albopictus or Ae. aegypti bites. Strong antigenicity to Ae. albopictus salivary proteins was detected in all individuals whatever the nature of Aedes exposure. Amongst these antigenic proteins, 68% are involved in blood feeding, including D7 protein family, adenosine deaminase, serpin and apyrase. This study provides an insight into the repertoire of Ae. albopictus immunogenic salivary proteins for the first time. © 2013 Royal Entomological Society.


Moriarty R.D.,Dublin City University | Martin A.,Dublin City University | Adamson K.,Dublin City University | Adamson K.,Royal College of Surgeons in Ireland | And 10 more authors.
Journal of Microscopy | Year: 2014

BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorophores are widely used in bioimaging to label proteins, lipids and nucleotides, but in spite of their attractive optical properties they tend to be prone to self-quenching because of their notably small Stokes shift. Herein, we compare two BODIPY compounds from a recently developed family of naphthyridine substituted BODIPY derivatives, one a visible emitting derivative (BODIPY-VIS) and one a near-infrared emitting fluorophore with a Stokes shift of approximately 165 nm as contrast reagents for live mammalian cells and murine brain tissue. The compounds were rendered water soluble by their conjugation to polyethylene glycol (PEG). Both PEGylated compounds exhibited good cell uptake compared with their parent compounds and confocal fluorescence microscopy revealed all dyes explored to be nuclear excluding, localizing predominantly within the lipophilic organelles; the endoplasmic reticulum and mitochondria. Cytotoxicity studies revealed that these BODIPY derivatives are modestly cytotoxic at concentrations exceeding 10 μM where they induce apoptosis and necrosis. Although the quantum yield of emission of the visible emitting fluorophore was over an order of magnitude greater than the Mega-Stokes shifted probe, the latter showed considerably reduced tendency to self quench and less interference from autofluorescence. The near-infrared probe also showed good penetrability and staining in live tissue samples. In the latter case similar tendency to exclude the nucleus and to localize in the mitochondria and endoplasmic reticulum was observed as in live cells. This to our knowledge is the first demonstration of such a Mega-Stokes BODIPY probe applied to cell and tissue imaging. Lay Description: BODIPY (4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene) is a widely used fluorescence molecule which can be used to label biological material such as proteins, lipids and nucleotides. Their optical properties are very attractive (for example they are very bright), however in spite of this they have a small separation between their maximum excitation and emission wavelengths (Stokes shift), which leads to a decrease in emission signal due to what is known as self quenching. Furthermore ideally they should emit in the Near Infra Red Region, where tissue transmits light well. Herein, we compare two BODIPY compounds from a recently developed family of naphthyridine substituted BODIPY derivatives, one with emission in the visible region of the spectra (BODIPY-VIS) and another with a near-infrared (NIR) emission. This NIR flourophore has a large Stokes shift of approximatly 165 nm in water, which overcomes the self quenching effect and can be used as a contrast reagent for live mammalian cells and murine brain tissue. The compounds were rendered water soluble by their bonding to polyethelene glycol (PEG). Both PEGylated compounds exhibited good cell uptake compared with their parent compounds and confocal fluorescence microscopy revealed all dyes explored to be nuclear excluding, localising predominantly within the lipophillic ("fat loving") organelles of the cells; the endoplasmic reticulum (ER) and mitochondria. Cytotoxicity studies revealed that these BODIPY derivatives induce modest cell death at concentrations exceeding 10 mM where each derivative induces a different mode of cell death, either by apoptotic or necrotic cell death pathways. Whereas the quantum yield (or brightness) of emission of the visible emitting fluorphore was over an order of magnitude greater than the large Stokes shifted NIR probe, the latter showed considerably reduced tendancy to self quench and less interference from autofluorescence. The NIR probe also showed good penetrability and staining in fixed and especially live tissue samples. In the latter case, a similar tendency to exclude the nucleus and to localise in the mitochondria and ER was observed as in live single cells. This to our knowledge is the first demonstration of such a larege Stokes shifted NIR BODIPY probe applied to cell and tissue imaging. © 2014 Royal Microscopical Society.


Schaeffer M.,French National Center for Scientific Research | Schaeffer M.,French Institute of Health and Medical Research | Schaeffer M.,Universities of Montpellier 1 and 2 | Schaeffer M.,Royal College of Surgeons in Ireland | And 19 more authors.
Endocrinology | Year: 2011

The secretion of endocrine hormones from pituitary cells finely regulates a multitude of homeostatic processes. To dynamically adapt to changing physiological status and environmental stimuli, the pituitary gland must undergo marked structural and functional plasticity. Endocrine cell plasticity is thought to primarily rely on variations in cell proliferation and size. However, cell motility, a process commonly observed in a variety of tissues during development, may represent an additional mechanism to promote plasticity within the adult pituitary gland. To investigate this, we used multiphoton time-lapse imaging methods, GH-enhanced green fluorescent protein transgenic mice and sexual dimorphism of the GH axis as a model of divergent tissue demand. Using these methods to acutely (12 h) track cell dynamics, we report that ovariectomy induces a dramatic and dynamic increase in cell motility, which is associated with gross GH-cell network remodeling. These changes can be prevented by estradiol supplementation and are associated with enhanced network connectivity as evidenced by increased coordinated GH-cell activity during multicellular calcium recordings. Furthermore, cell motility appears to be sex-specific, because reciprocal alterations are not detected in males after castration. Therefore, GH-cell motility appears to play an important role in the structural and functional pituitary plasticity, which is evoked in response to changing estradiol concentrations in the female. Copyright © 2011 by The Endocrine Society.


Hodson D.J.,CNRS Lyon Institute of Functional Genomics | Hodson D.J.,French National Center for Scientific Research | Hodson D.J.,French Institute of Health and Medical Research | Hodson D.J.,Universities of Montpellier 1 and 2 | And 16 more authors.
Journal of Neuroendocrinology | Year: 2010

Endocrine cells in the mammalian pituitary are arranged into three-dimensional homotypic networks that wire the gland and act to optimise hormone output by allowing the transmission of information between cell ensembles in a temporally precise manner. Despite this, the structure-function relationships that allow cells belonging to these networks to display coordinated activity remain relatively uncharacterised. This review discusses the recent technological advances that have allowed endocrine cell network structure and function to be probed and the mathematical models that can be used to analyse and present the resulting data. In particular, we focus on the mechanisms that allow endocrine cells to dynamically function as a population to drive hormone release as well as the experimental and theoretical methods that are used to track and model information flow through the network. © 2010 The Authors. Journal of Neuroendocrinology © 2010 Blackwell Publishing Ltd.


Andoniadou C.L.,University College London | Matsushima D.,University of North Carolina at Chapel Hill | Mousavy Gharavy S.N.,University College London | Signore M.,University College London | And 14 more authors.
Cell Stem Cell | Year: 2013

Sox2+ adult mouse pituitary cells can self-renew and terminally differentiate in vitro, but their physiological role in vivo and possible contribution to oncogenesis remain largely unknown. Using genetic lineage tracing, we show here that the Sox2+ cell compartment of both the embryonic and adult pituitary contains stem/progenitor cells that are able to differentiate into all hormone-producing lineages and contribute to organ homeostasis during postnatal life. In addition, we show that targeted expression of oncogenic β-catenin in Sox2+ cells gives rise to pituitary tumors, but, unexpectedly, the tumor mass is not derived from the Sox2 + mutation-sustaining cells, suggesting a paracrine role of Sox2 + cells in pituitary oncogenesis. Our data therefore provide in vivo evidence of a role for Sox2+ stem/progenitor cells in long-term physiological maintenance of the adult pituitary, and highlight an unexpected non-cell-autonomous role for these cells in the induction of pituitary tumors. Video Abstract © 2013 Elsevier Inc.


Rognon P.,University Paris Diderot | Rognon P.,CNRS Paul Pascal Research Center | Molino F.,Universities of Montpellier 1 and 2 | Gay C.,University Paris Diderot | Gay C.,University of Sydney
EPL | Year: 2010

Liquid foams have been observed to behave like immersed granular materials in at least one respect: deformation tends to raise their liquid contents, a phenomenon called dilatancy. While experimental observations evidenced the effect of a continuous deformation rate (dynamic dilatancy), we present a geometrical interpretation of both main contributions to elastic dilatancy (during elastic deformation) in foams squeezed between two solid plates (2D GG foams), which contain pseudo Plateau borders along the plates, and in 3D foams. The positive contribution is related to the increase in total Plateau border length while the negative contribution reflects the increase in total surface area of the foam. In 2D, we show that the negative dilatancy predicted by Weaire and Hutzler (Philos. Mag., 83 (2003) 2747) at very low liquid fractions is specific to ideal 2D foams (with no glass plates). In 3D, we predict that dilatancy should be positive at low liquid fractions (below 1%) and negative at moderate liquid fractions (above 4%). Copyright © EPLA, 2010.


Gay C.,University Paris Diderot | Rognon P.,University Paris Diderot | Rognon P.,CNRS Paul Pascal Research Center | Reinelt D.,Southern Methodist University | Molino F.,Universities of Montpellier 1 and 2
European Physical Journal E | Year: 2011

Up to a global scaling, the geometry of foams squeezed between two solid plates (2D GG foams) essentially depends on two independent parameters: the liquid volume fraction and the degree of squeezing (bubble thickness to diameter ratio). We describe it in two main asymptotic regimes: fully dry floor tiles, where the Plateau border radius is smaller than the distance between the solid plates, and dry pancakes, where it is larger. We predict a rapid variation of the Plateau border radius in one part of the pancake regime, namely when the Plateau border radius is larger than the inter-plate distance but smaller than the geometric mean of that distance and the bubble perimeter. This rapid variation is not related to any topological change in the foam: in all the regimes we consider, the bubbles remain in mutual lateral contact through films located at mid-height between both plates. We provide asymptotic predictions in different types of experiments on such 2D GG foams: when foam is being progressively dried or wetted, when it is being squeezed further or stretched, when it coarsens through film breakage or through inter-bubble gas diffusion. Our analysis is restricted to configurations close to equilibrium, as we do not include stresses resulting from bulk viscous flow or from non-homogeneous surfactant concentrations. We also assume that the inter-plate distance is sufficiently small for gravity to be negligible. The present work does not provide a method for measuring small Plateau border radii experimentally, but it indicates that large (and easily observable) Plateau borders should appear or disappear rather suddenly in some types of experiments with small inter-plate gaps. It also gives expected orders of magnitude that should be helpful for designing experiments on 2D GG foams. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


PubMed | Universities of Montpellier 1 and 2
Type: Journal Article | Journal: Endocrinology | Year: 2011

The secretion of endocrine hormones from pituitary cells finely regulates a multitude of homeostatic processes. To dynamically adapt to changing physiological status and environmental stimuli, the pituitary gland must undergo marked structural and functional plasticity. Endocrine cell plasticity is thought to primarily rely on variations in cell proliferation and size. However, cell motility, a process commonly observed in a variety of tissues during development, may represent an additional mechanism to promote plasticity within the adult pituitary gland. To investigate this, we used multiphoton time-lapse imaging methods, GH-enhanced green fluorescent protein transgenic mice and sexual dimorphism of the GH axis as a model of divergent tissue demand. Using these methods to acutely (12 h) track cell dynamics, we report that ovariectomy induces a dramatic and dynamic increase in cell motility, which is associated with gross GH-cell network remodeling. These changes can be prevented by estradiol supplementation and are associated with enhanced network connectivity as evidenced by increased coordinated GH-cell activity during multicellular calcium recordings. Furthermore, cell motility appears to be sex-specific, because reciprocal alterations are not detected in males after castration. Therefore, GH-cell motility appears to play an important role in the structural and functional pituitary plasticity, which is evoked in response to changing estradiol concentrations in the female.

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