3,371 research outputs found
An integrated study of the development of organic rice cultivation in the Camargue (France)-
In the Camargue, rice and durum wheat are associated in rotations that have an ambivalent ecological impact: on the one hand, these two crops contribute to the preservation of the surrounding ecosystem, while on the other hand, when cropped intensively, they can threaten the ecological equilibrium of this protected area. In this context, organic agriculture would seem to be an alternative adopted by a certain number of producers and processors. However, the pioneers of this practice encounter numerous problems, both agronomic and economic. The study presented here aims: to construct a pluridisciplinary approach to analyse the conditions of the development of organic cereal cultivation in the Camargue: to identify the principal factors that limit the development of this new practice: to produce knowledge useful in helping ricegrowers put into practice organic cropping systems
Regulated release of BDNF by cortical oligodendrocytes is mediated through metabotropic glutamate receptors and the PLC pathway
A number of studies suggest that OLGs (oligodendrocytes), the myelinating cells of the central nervous system, are also a source of trophic molecules, such as neurotrophins that may influence survival of proximate neurons. What is less clear is how the release of these molecules may be regulated. The present study investigated the effects of BDNF (brain-derived neurotrophic factor) derived from cortical OLGs on proximate neurons, as well as regulatory mechanisms mediating BDNF release. Initial work determined that BDNF derived from cortical OLGs increased the numbers of VGLUT1 (vesicular glutamate transporter 1)-positive glutamatergic cortical neurons. Furthermore, glutamate acting through metabotropic, and not AMPA/kainate or NMDA (N-methyl-d-aspartate), receptors increased BDNF release. The PLC (phospholipase C) pathway is a key mediator of metabotropic actions to release BDNF in astrocytes and neurons. Treatment of OLGs with the PLC activator m-3M3FBS [N-(3-trifluoromethylphenyl)-2,4,6-trimethylbenzenesulfonamide] induced robust release of BDNF. Moreover, release elicited by the metabotropic receptor agonist ACPD [trans-(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid] was inhibited by the PLC antagonist U73122, the IP3 (inositol triphosphate 3) receptor inhibitor 2-APB (2-aminoethoxydiphenylborane) and the intracellular calcium chelator BAPTA/AM [1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid tetrakis(acetoxymethyl ester)]. Taken together, these results suggest that OLG lineage cells release BDNF, a molecule trophic for proximate neurons. BDNF release is regulated by glutamate acting through mGluRs (metabotropic glutamate receptors) and the PLC pathway. Thus glutamate and BDNF may be molecules that support neuron–OLG interactions in the cortex
Use of recombinant ApxIV in serodiagnosis of Actinobacillus pleuropneumoniae infections and development of an ApxIV ELISA
Actinobacillus pleuropneumoniae (App) is the etiological agent of porcine pleuropneumonia. The virulence of the fifteen serotypes of App is mainly determined by the three major RTX toxins ApxI, ApxII and ApxIII, which are secreted by the different serotypes in various combinations. A fourth RTX toxin, ApxIV, is produced by all 15 serotypes specifically during infection of pigs, but not under in vitro conditions. Pigs infected with App show specific antibodies directed against ApxIV. The analysis of sera of experimentally infected pigs revealed that ApxIV-immunoblots detected App infections in the second to third week post infection. We developed an indirect ELISA based on purified recombinant N’-terminal moiety of ApxIV that showed a specificity of 100% and a sensitivity of 93.8%
Peuplements forestiers artificiels en région méditerranéenne : vers une re-naturalisation.
Les reboisements ont longtemps fait partie des politiques sylvicoles en région méditerranéenne, où la restauration de peuplements forestiers a été réalisée avec succès par les générations passées, grâce à des essences pionnières, dont plusieurs espèces de Pins. Or, on constate qu'après la reconstitution d'un sol et d'une ambiance forestière, ces forêts sont entrées depuis plusieurs décennies dans un processus lent de maturation sylvigénétique se traduisant, dans l'étage montagnard sub-méditerranéen, par l'apparition ou la réapparition d'essences telles que le Hêtre ou le Sapin, notamment. Peut-on alors parler de naturalisation de ces peuplements artificiels ? Une étude menée de 1998 à 2001 dans les pinèdes artificielles du Mont-Ventoux a permis d'explorer quelques pistes permettant de contribuer à la connaissance d'une telle évolution. À terme, on souhaite aboutir à des outils d'aide à la décision vraiment opérationnels, couplant simulateurs et SIG
Les dynamiques en cours et l'impact des pratiques sylvicoles.
Sous l'action des processus naturels et en interaction avec la gestion forestière, plusieurs dynamiques forestières sont à l' uvre sur le mont Ventoux. Suivant ses objectifs, le gestionnaire en accompagne certaines, lutte contre d'autres ou encore se contente de les observer. Dans le contexte des changements environnementaux (notamment climatiques), il est primordial de mieux connaître ces dynamiques, afin de pouvoir élaborer des stratégies de gestion anticipatives
El cinema y la guerra. A propĂłsito de "Las Cruces de Madera"
Dreyfus, JP. (1932). El cinema y la guerra. A propĂłsito de "Las Cruces de Madera". Nuestro cinema. (1):21-23. http://hdl.handle.net/10251/42783.ImportaciĂłn Masiva2123
The Syndrome of Arthrogryposis and Palatoschisis (SAP) in Charolais cattle; Abnormal motor innervation and defect in the focalization of 16 S acetylcholinesterase in the end-plates rich regions of the muscle
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