The Barrier Properties of the Skin of Aquatic and Semi-Aquatic Vertebrates

Vertebrate skin is a heterogeneous organ that acts as a barrier to the external environment. A crucial structure for skin barrier function is the tight junction (TJ) complex that links skin epidermal cells. TJ proteins have been examined in mammalian skin but little is known about skin TJ proteins of vertebrates residing permanently or semi-permanently in water. This thesis provides new insights into the effect of abiotic and biotic factors on skin of fishes and amphibians using rainbow trout and the Australian green tree frog as models. The effects of water ion content and photoperiod on skin barrier properties and TJ proteins of trout are reported. Additionally, the effects of a deadly amphibian fungus, Batrachochytrium dendrobatidis, on skin TJ proteins of a frog are documented for the first time. This thesis provides novel information on skin TJ proteins of aquatic and semi-aquatic vertebrates and how they respond to environmental change.