Proteomic Analysis of Rta2p-Dependent Raft-Association of Detergent-Resistant Membranes in Candida albicans

In Candida albicans, lipid rafts (also called detergent-resistant membranes, DRMs) are involved in many cellular processes and contain many important proteins. In our previous study, we demonstrated that Rta2p was required for calcineurin-mediated azole resistance and sphingoid long-chain base release in C. albicans. Here, we found that Rta2p was co-localized with raft-constituted ergosterol on the plasma membrane of C. albicans. Furthermore, this membrane expression pattern was totally disturbed by inhibitors of either ergosterol or sphingolipid synthesis. Biochemical fractionation of DRMs together with immunoblot uncovered that Rta2p, along with well-known DRM-associated proteins (Pma1p and Gas1p homologue), was associated with DRMs and their associations were blocked by inhibitors of either ergosterol or sphingolipid synthesis. Finally, we used the proteomic analysis together with immunoblot and identified that Rta2p was required for the association of 10 proteins with DRMs. These 5 proteins (Pma1p, Gas1p homologue, Erg11p, Pmt2p and Ali1p) have been reported to be DRM-associated and also that Erg11p is a well-known target of azoles in C. albicans. In conclusion, our results showed that Rta2p was predominantly localized in lipid rafts and was required for the association of certain membrane proteins with lipid rafts in C. albicans

Observing “Weeds” to Understand Local Perceptions of Environmental Change in a Temperate Rural Area of Southwestern France

International audienceRural areas of the temperate European countries are affected by climate changes that are not always perceived by local communities. We focus on how local discourses on biodiversity, in our case wild flora, provide insight into what people see as changing in their environment. We conducted ethnographic research, including interviews and participant observation, on perceptions of biodiversity change in Bas-Comminges, a rural area of France where agriculture consists primarily of extensive mixed farming. Wild flora management there is shaped by traditional agricultural practices, rural and agricultural policies, and warmer temperatures and other climatic changes. We will show that (1) wild flora is seen as growing and expanding due to changes in local institutions in charge of green spaces, changes in agriculture, and warmer temperatures; (2) discourses on those impacts reveal different types of knowledge and uses of local flora; and (3) social conflicts are emerging around local flora management, and these conflicts reveal tensions between different objectives for the land within a changing community. We will demonstrate that warmer temperatures are not always linked to global climate changes by local residents and that environmental and social changes cannot be apprehended separately from climatic ones. More broadly, we want to understand how rural populations are facing and adapting to the major transformations of their land and society, and we show that conflicts can be used by different types of local residents to take back control of their land and maintain their communities. This research is part of a larger interdisciplinary and comparative program on local perceptions of environmental change funded by the French Agence Nationale de la Recherche (ANR)