Michelle Clement - Cutaneous water loss and covalently bound lipids of the stratum corneum in nestling house sparrows (Passer domesticus) from desert and mesic habitats

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      Publication Details (including relevant citation   information):

      Michelle E. Clement, Agusti Munoz-Garcia, Joseph B. Williams,   Journal of Experimental Biology (in press).


      Lipids   of the stratum corneum (SC), the outer layer of the epidermis of   birds and mammals, provide a barrier to water vapor diffusion   through the skin. The SC of birds consists of flat dead cells,   called corneocytes, and two lipid compartments: an intercellular   matrix and a monolayer of covalently bound lipids (CBL) attached   to the outer surface of corneocytes. We previously found two   classes of sphingolipids, ceramides and cerebrosides, covalently   bound to corneocytes in the SC of house sparrows (Passer   domesticus, L.); these lipids were associated with cutaneous   water loss (CWL). In this study, we collected adult and nestling   house sparrows from Ohio and nestlings from Saudi Arabia,   acclimated them to either high or low humidity, and measured   their rates of CWL. We also measured CWL for natural populations   of nestlings from Ohio and Saudi Arabia, beginning when chicks   were 2 days old until they fledged. We then evaluated the   composition of the CBL of the SC of sparrows using thin layer   chromatography. We found that adult house sparrows had a greater   diversity of CBLs in their SC than previously described. During   ontogeny, nestling sparrows increased the amount of CBL and   developed their CBL differently, depending on their habitat.   Acclimating nestlings to different humidity regimes did not alter   the ontogeny of CBL, suggesting that these lipids represent a   fundamental component of SC organization that does not respond to   short-term environmental changes.

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