Cell-autonomous and environmental contributions to the interstitial migration of T cells

A key to understanding the functioning of the immune system is to define the mechanisms that facilitate directed lymphocyte migration to and within tissues. The recent development of improved imaging technologies, most prominently multi-photon microscopy, has enabled the dynamic visualization of immune cells in real-time directly within intact tissues. Intravital imaging approaches have revealed high spontaneous migratory activity of T cells in secondary lymphoid organs and inflamed tissues. Experimental evidence points towards both environmental and cell-intrinsic cues involved in the regulation of lymphocyte motility in the interstitial space. Based on these data, several conceptually distinct models have been proposed in order to explain the coordination of lymphocyte migration both at the single cell and population level. These range from “stochastic” models, where chance is the major driving force, to “deterministic” models, where the architecture of the microenvironment dictates the migratory trajectory of cells. In this review, we focus on recent advances in understanding naïve and effector T cell migration in vivo. In addition, we discuss some of the contradictory experimental findings in the context of theoretical models of migrating leukocytes

Local Abundance Patterns of Noctuid Moths in Olive Orchards: Life-History Traits, Distribution Type and Habitat Interactions

Local species abundance is related to range size, habitat characteristics, distribution type, body size, and life-history variables. In general, habitat generalists and polyphagous species are more abundant in broad geographical areas. Underlying this, local abundance may be explained from the interactions between life-history traits, chorological pattern, and the local habitat characteristics. The relationship within taxa between life-history traits, distribution area, habitat characteristics, and local abundance of the noctuid moth (Lepidoptera: Noctuidae) assemblage in an olive orchard, one of the most important agro-ecosystems in the Mediterranean basin, was analyzed. A total of 66 species were detected over three years of year-round weekly samplings using the light-trap method. The life-history traits examined and the distribution type were found to be related to the habitat-species association, but none of the biological strategies defined from the association to the different habitats were linked with abundance. In contrast to general patterns, dispersal ability and number of generations per year explained differences in abundance. The relationships were positive, with opportunistic taxa that have high mobility and several generations being locally more abundant. In addition, when the effect of migrant species was removed, the distribution type explained abundance differences, with Mediterranean taxa (whose baricenter is closer to the studied area) being more abundant

Barcoding T Cell Calcium Response Diversity with Methods for Automated and Accurate Analysis of Cell Signals (MAAACS)

International audienceWe introduce a series of experimental procedures enabling sensitive calcium monitoring in T cell populations by confocal video-microscopy. Tracking and post-acquisition analysis was performed using Methods for Automated and Accurate Analysis of Cell Signals (MAAACS), a fully customized program that associates a high throughput tracking algorithm, an intuitive reconnection routine and a statistical platform to provide, at a glance, the calcium barcode of a population of individual T-cells. Combined with a sensitive calcium probe, this method allowed us to unravel the heterogeneity in shape and intensity of the calcium response in T cell populations and especially in naive T cells, which display intracellular calcium oscillations upon stimulation by antigen presenting cells

Two-photon microscopy analysis of leukocyte trafficking and motility

During the last several years, live tissue imaging, in particular using two-photon laser microscopy, has advanced our understanding of leukocyte trafficking mechanisms. Studies using this technique are revealing distinct molecular requirements for leukocyte migration in different tissue environments. Also emerging from the studies are the ingenious infrastructures for leukocyte trafficking, which are produced by stromal cells. This review summarizes the recent imaging studies that provided novel mechanistic insights into in vivo leukocyte migration essential for immunosurveillance

Un dernier mot sur l’enseignement des langues vivantes à l’École normale

Boursin P. Un dernier mot sur l’enseignement des langues vivantes à l’École normale. In: Manuel général de l'instruction primaire : journal hebdomadaire des instituteurs. 74e année, tome 43, 1906. pp. 579-580

A l'étranger

Boursin P. A l'étranger. In: Manuel général de l'instruction primaire : journal hebdomadaire des instituteurs. 73e année, tome 42, 1905. pp. 621-623

La réforme de l’enseignement du dessin dans les écoles primaires élémentaires

Boursin P. La réforme de l’enseignement du dessin dans les écoles primaires élémentaires. In: La revue pédagogique, tome 58, Janvier-Juin 1911. pp. 320-334

La méthode directe dans l’enseignement des langues

Boursin P. La méthode directe dans l’enseignement des langues. In: Manuel général de l'instruction primaire : journal hebdomadaire des instituteurs. 74e année, tome 43, 1906. pp. 386-388

La réforme de l’enseignement du dessin dans les écoles primaires élémentaires

Boursin P. La réforme de l’enseignement du dessin dans les écoles primaires élémentaires. In: La revue pédagogique, tome 58, Janvier-Juin 1911. pp. 320-334