Over the past several decades, rapid decline in adult stony-coral (comprising the Orders Scleractinia and Anthomedusae, specifically Family Milleporidae) cover has occurred concurrent with an increase in adult octocoral (Octocorallia/gorgonian) cover along the Florida Reef Tract. In January 2010, the Florida Keys experienced extremely cold air and water temperatures, below the lethal threshold for many reef organisms including corals. Very high stony-coral mortality occurred on some patch reefs. The newly-available space created by this disturbance event provided the opportunity for recruitment and settlement of new coral larvae and other reef organisms. The goal of this study was to examine post-disturbance recruitment and survival of juvenile stony corals and octocorals on patch reefs in the Middle and Upper Florida Reef Tract. Permanent quadrats were established at eight patch-reef sites. Stony-coral and octocoral juveniles, visible to the naked eye and having a maximum 4 cm diameter for stony corals or 4 cm height for octocorals, were identified, measured, and photographed to track each colony through spring and fall for two years. Juvenile densities increased significantly over that time; octocoral density increased with higher significance (p Opportunistic and/or hardy organisms are re-populating patch-reef sites, whereas slower growing, massive stony-coral species are declining. When a reef environment is plagued with chronic stressors, such as terrestrial runoff, overfishing, high temperature fluctuations and turbidity, the succession process may be inhibited following acute disturbances such as cold-water events. Patch reefs of the Florida Reef Tract now appear to be caught in a perpetually disturbed state, which supports opportunistic and hardy taxa and inhibits recovery of slower-growing climax taxa that dominated until the past few decades.

Le glioblastome (GBM) est la tumeur cérébrale primaire la plus agressive comportant une sous-population de cellules souches tumorales (CSG). Elles sont capables d’auto-renouvellement, de prolifération, de différenciation en cellules exprimant les marqueurs neuraux et de trans-différenciation en cellules de types vasculaires. Dans ce contexte, j’ai dérivé et caractérisé plusieurs lignées de CSG à partir de biopsies de patients. Puis j’ai évalué l’impact des peptides thérapeutiques transmembranaires développés au laboratoire, visant les plateformes de récepteurs de neuropiline-1 et de plexine-A1 surexprimées dans les CSG. Les deux peptides diminuent la croissance des CSG in vitro et in vivo. Finalement, j’ai développé un outil génétique fluorescent permettant de suivre le destin des CSG en direct. Basé sur l’expression de 4 rapporteurs fluorescents contrôlés par des promoteurs spécifiques des types cellulaires, il permet d’identifier l’hétérogénéité de ces cellules en différenciation. / The glioblastoma multiforme (GBM) is the most aggressive primary brain tumor and includes a subpopulation of tumoral stem cells (CSG). Those cells can self-renew, proliferate and differentiate by expressing specific neural markers and/or transdifferentiate into vascular-like cells. In this context, my work consisted first to produce and characterize several CSG lines from patient biopsies to constitute a bank of cell lines with different properties. We also evaluated the impact of in house therapeutic transmembrane peptides targeting the neuropilin-1 / plexin-A1 receptor platforms overexpressed in GBM. We thus showed that both targeting peptides decrease the growth of GSC in in vitro and in vivo models. Finally, I developed an inducible mosaic expression system to track the live differentiation of CSG. This system is based on the expression of four different fluorescent reporters controlled by the activity of cell type specific promoters.