Agriculture urbaine : un outil multidimensionnel pour le développement des quartiers

Depuis plus de 30 ans différentes expériences en agriculture urbaine (AU) ont eu lieu à Montréal (Québec, Canada). Le programme des jardins communautaires, géré par la Ville, et 6 jardins collectifs, gérés par des organisations communautaires, sont examinés dans le cadre de cet article. Ces expériences visent différents objectifs dont la sécurité alimentaire, la sociabilisation et l’éducation. Ceux-ci évoluent au niveau temporel mais se différencient aussi géographiquement (quartiers). Il en ressort que les initiatives en AU à Montréal s’avère un lieu de production de légumes non négligeable, un lieu de sociabilisation et d’éducation favorisant un développement social individuel et collectifs des quartiers ayant une forte présence de population économique défavorisée. ABSTRACT: For over 30 years, different urban agriculture (UA) experiments have been undertaken in Montreal (Quebec, Canada). The Community Gardening Program, managed by the City, and 6 collective gardens, managed by community organizations, are discussed in this article. These experiments have different objectives, including food security, socialization and education. Although these have changed over time, they have also differed depending on geographic location (neighbourhood). The UA initiatives in Montreal have resulted in the development of a centre with a significant vegetable production and a socialization and education environment that fosters individual and collective social development in districts with a significant economically disadvantaged population. The various approaches attain the established objectives and these are multi-dimensional tools used for the social development of disadvantaged populations

Mapping CRMP3 domains involved in dendrite morphogenesis and voltage-gated calcium channel regulation

Although hippocampal neurons are well-distinguished by the morphological characteristics of their dendrites and their structural plasticity, the mechanisms involved in regulating their neurite initiation, dendrite growth, network formation and remodeling are still largely unknown, in part because the key molecules involved remain elusive. Identifying new dendrite-active cues could uncover unknown molecular mechanisms that would add significant understanding to the field and possibly lead to the development of novel neuroprotective therapy because these neurons are impaired in many neuropsychiatric disorders. In our previous studies, we deleted the gene encoding CRMP3 in mice and identified the protein as a new endogenous signaling molecule that shapes diverse features of the hippocampal pyramidal dendrites without affecting axon morphology. We also found that CRMP3 protects dendrites against dystrophy induced by prion peptide PrP106-126. Here, we report that CRMP3 has a profound influence on neurite initiation and dendrite growth of hippocampal neurons in vitro. Our deletional mapping revealed that the C-terminus of CRMP3 probably harbors its dendritogenic capacity and supports an active transport mechanism. By contrast, overexpression of the C-terminal truncated CRMP3 phenocopied the effect of CRMP3 gene deletion with inhibition of neurite initiation or decrease in dendrite complexity, depending on the stage of cell development. In addition, this mutant inhibited the activity of CRMP3, in a similar manner to siRNA. Voltage-gated calcium channel inhibitors prevented CRMP3-induced dendritic growth and somatic Ca2+ influx in CRMP3-overexpressing neurons was augmented largely via L-type channels. These results support a link between CRMP3-mediated Ca2+ influx and CRMP3-mediated dendritic growth in hippocampal neurons

Agriculture urbaine : un outil multidimensionnel pour le développement des quartiers

For over 30 years, different urban agriculture (UA) experiments have been undertaken in Montreal (Quebec, Canada). The Community Gardening Program, managed by the City, and 6 collective gardens, managed by community organizations, are discussed in this article. These experiments have different objectives, including food security, socialization and education. Although these have changed over time, they have also differed depending on geographic location (neighbourhood). The UA initiatives in Montreal have resulted in the development of a centre with a significant vegetable production and a socialization and education environment that fosters individual and collective social development in districts with a significant economically disadvantaged population. The various approaches attain the established objectives and these are multi-dimensional tools used for the social development of disadvantaged populations

The repair rate of radiation-induced DNA damage: a stochastic interpretation based on the gamma function.

International audienceThere is a large body of evidence that stress-induced DNA damage may be responsible for cell lethality, cancer proneness and/or immune reaction. However, statistical features of their repair rate remain poorly documented. In order to interpret the shape of the radiation-induced DNA damage repair curves with a minimum of biological assumptions, we introduced the concept of repair probability, specific to any individual radiation-induced DNA damage, whatever its biochemical type. We strengthened the apparent paradox that the repair rate of a population of DNA damage is time-dependent even if the repair rate of the individual DNA damage is constant. Hence, the existing models, based on a dual approach of the DNA repair may be insufficient for describing the DNA repair rate over a large range of repair times. Since the repair probability of DNA damage cannot be assessed individually, the measurement of the DNA repair rate is assumed to consist in determining the instantaneous mean of all repair probabilities. The relevance of this model was examined with different endpoints: cell species, genotypes, radiation type and chromatin condensation. The Euler's Gamma function was shown to provide the distribution the most consistent with such hypotheses. Furthermore, formulas, deduced from the Gamma distribution, were found to be compatible with our previous model, empirically defined but based on a variable repair half-time

Involvement Of Collapsin Response Mediator Proteins In The Neurite Extension Induced By Neurotrophins In Dorsal Root Ganglion Neurons

The pattern of sensory neuron extensions and connections is established during embryonic development through complex and varied guidance cues that control motility of growth cones and neurite morphogenesis. Semaphorins and neurotrophins are molecules that act as such cues. Collapsin response mediator proteins (CRMPs) are thought to be part of the semaphorin signal transduction pathway implicated in semaphorin-induced growth cone collapse. In this report, we present evidence that CRMPs are also involved in the neurite extension controlled by neurotrophins. We found that specific antibodies and the dominant-negative mutant protein for CRMP2 both potentiated the neurite extension induced by NGF, while specific antibodies and the corresponding mutant protein for CRMP1 both abolished the neurite extension induced by NT3. Our data suggest that CRMP2 has a negative effect on neurite extension induced by NGF and CRMP1 participates in the neurite formation/extension induced by NT3. These results point to a function for CRMPs in the regulation of neurite outgrowth induced by neurotrophins in sensory neurons. © 2004 Elsevier Inc. All rights reserved

Opposing Morphogenetic Defects on Dendrites and Mossy Fibers of Dentate Granular Neurons in CRMP3-Deficient Mice

Collapsin response mediator proteins (CRMPs) are highly expressed in the brain during early postnatal development and continue to be present in specific regions into adulthood, especially in areas with extensive neuronal plasticity including the hippocampus. They are found in the axons and dendrites of neurons wherein they contribute to specific signaling mechanisms involved in the regulation of axonal and dendritic development/maintenance. We previously identified CRMP3's role on the morphology of hippocampal CA1 pyramidal dendrites and hippocampus-dependent functions. Our focus here was to further analyze its role in the dentate gyrus where it is highly expressed during development and in adults. On the basis of our new findings, it appears that CRMP3 has critical roles both in axonal and dendritic morphogenesis of dentate granular neurons. In CRMP3-deficient mice, the dendrites become dystrophic while the infrapyramidal bundle of the mossy fiber shows aberrant extension into the stratum oriens of CA3. This axonal misguided projection of granular neurons suggests that the mossy fiber-CA3 synaptic transmission, important for the evoked propagation of the activity of the hippocampal trisynaptic circuitry, may be altered, whereas the dystrophic dendrites may impair the dynamic interactions with the entorhinal cortex, both expected to affect hippocampal function.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]