Absence of plastin 1 causes abnormal maintenance of hair cell stereocilia and a moderate form of hearing loss in mice

Hearing relies on the mechanosensory inner and outer hair cells (OHCs) of the organ of Corti, which convert mechanical deflections of their actin-rich stereociliary bundles into electrochemical signals. Several actin-associated proteins are essential for stereocilia formation and maintenance, and their absence leads to deafness. One of the most abundant actin-bundling proteins of stereocilia is plastin 1, but its function has never been directly assessed. Here, we found that plastin 1 knock-out (Pls1 KO) mice have a moderate and progressive form of hearing loss across all frequencies. Auditory hair cells developed normally in Pls1 KO, but in young adult animals, the stereocilia of inner hair cells were reduced in width and length. The stereocilia of OHCs were comparatively less affected; however, they also showed signs of degeneration in ageing mice. The hair bundle stiffness and the acquisition of the electrophysiological properties of hair cells were unaffected by the absence of plastin 1, except for a significant change in the adaptation properties, but not the size of the mechanoelectrical transducer currents. These results show that in contrast to other actin-bundling proteins such as espin, harmonin or Eps8, plastin 1 is dispensable for the initial formation of stereocilia. However, the progressive hearing loss and morphological defects of hair cells in adult Pls1 KO mice point at a specific role for plastin 1 in the preservation of adult stereocilia and optimal hearing. Hence, mutations in the human PLS1 gene may be associated with relatively mild and progressive forms of hearing loss

Etude à l'échelle de la plante entière du fonctionnement hydrique et photosynthétique de la vigne: comparaison des systèmes de conduite traditionnel et en Lyre

Le fonctionnement hydrique et photosynthétique à l'échelle des ceps entiers a été suivi simultanément en milieu naturel sur des vignes étroites traditionnelles et conduites en Lyre. Cette étude a été réalisée sur Cabernet Sauvignon/101-14, planté en sol de graves. Les observations relatives au comportement hydrique (potentiel hydrique et foliaire, transpiration, par unite de surface foliaire) des deux systèmes de conduite utilisés indiquent que la vigne traditionnelle se trouve dans un meilleur état hydrique comparativement à la vigne conduite en Lyre. Cette différence est en rapport avec les valeurs de l'assimilation nette par unité de surface foliaire, nettement supérieures sur la vigne traditionnelle. Il semble toutefois que l'existence d'une surface foliaire par surface de sol plus importante chez la vigne conduite en Lyre compense le taux réduit de photosynthèse par unité de surface folaire. Cette compensation conduit à une production agronomique voisine chez les deux systèmes de conduite.La conclusion principale de cette étude est qu'une contrainte hydrique ayant un effet dépressif sur l'assimilation nette peut avoir, en revanche, des conséqences favorables sur l'élaboration des critères qualitatifs, notamment la synthèse des polyphénols.Photosynthesis and transpiration studies with traditionally and lyre-trained vinesWater and photosynthetic functions on a plant scale were studied simultaneously on traditionally and lyre-shaped grapevines grown in field conditions. The study was carried out on Cabernet Sauvignon/101-14 planted in gravelly soil. Observations concerning the water behavior (leaf water potential, transpiration per leaf surface unit) of both training systems used indicate that the traditional vine manifests a better water status when compared with the lyre-shaped vine. The difference is in agreement with net photosynthesis values per leaf surface unit, clearly superior on the traditional vine. It seems, however, that the existence of a greater leaf surface per soil surface in the lyre-shaped vine compensates the reduction in photosynthesis per leaf surface. The compensation results in very close agronomical yield for both training systems. The main conclusion of this study is that a water constraint having a diminishing effect on net photosynthesis can, on the other hand, have favorable consequences on the elaboration of qualitative criteria, in particular, the synthesis of polyphenols

Proceedings of the second "international Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST'14)

The implicit objective of the biennial "international - Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST) is to foster collaboration between international scientific teams by disseminating ideas through both specific oral/poster presentations and free discussions. For its second edition, the iTWIST workshop took place in the medieval and picturesque town of Namur in Belgium, from Wednesday August 27th till Friday August 29th, 2014. The workshop was conveniently located in "The Arsenal" building within walking distance of both hotels and town center. iTWIST'14 has gathered about 70 international participants and has featured 9 invited talks, 10 oral presentations, and 14 posters on the following themes, all related to the theory, application and generalization of the "sparsity paradigm": Sparsity-driven data sensing and processing; Union of low dimensional subspaces; Beyond linear and convex inverse problem; Matrix/manifold/graph sensing/processing; Blind inverse problems and dictionary learning; Sparsity and computational neuroscience; Information theory, geometry and randomness; Complexity/accuracy tradeoffs in numerical methods; Sparsity? What's next?; Sparse machine learning and inference.Comment: 69 pages, 24 extended abstracts, iTWIST'14 website: http://sites.google.com/site/itwist1

Pattern formation in 2-frequency forced parametric waves

We present an experimental investigation of superlattice patterns generated on the surface of a fluid via parametric forcing with 2 commensurate frequencies. The spatio-temporal behavior of 4 qualitatively different types of superlattice patterns is described in detail. These states are generated via a number of different 3--wave resonant interactions. They occur either as symmetry--breaking bifurcations of hexagonal patterns composed of a single unstable mode or via nonlinear interactions between the two primary unstable modes generated by the two forcing frequencies. A coherent picture of these states together with the phase space in which they appear is presented. In addition, we describe a number of new superlattice states generated by 4--wave interactions that arise when symmetry constraints rule out 3--wave resonances.Comment: The paper contains 34 pages and 53 figures and provides an extensive review of both the theoretical and experimental work peformed in this syste

MRI of intact plants

Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transport in the stem, e.g., as a function of environmental (stress) conditions. Non-spatially resolved portable NMR is becoming available to study leaf water content and distribution of water in different (sub-cellular) compartments. These parameters directly relate to stomatal water conductance, CO2 uptake, and photosynthesis. MRI applied on plants is not a straight forward extension of the methods discussed for (bio)medical MRI. This educational review explains the basic physical principles of plant MRI, with a focus on the spatial resolution, factors that determine the spatial resolution, and its unique information for applications in plant water relations that directly relate to plant photosynthetic activity

Early effects of increased CO2 on growth and metabolism of young walnut

National audienc

El Nabab : novela

Tradutor tomado do verso da portadaBNE, 10/11/2016, da como data probable da edición 194