Abstract

The Antarctic ecosystems are undergoing the effects of global climate change. Consequently, Antarctic ecosystems are changing, some at a rapid rate while others are relatively stable. The ocean surface temperatures in the Antarctic Peninsula have increased by approximately 2°C. In addition, the increasing ocean surface pCO2 in the polar ocean could be enhancing the stress on the Antarctic marine ecosystem. Several marine invertebrates have some molecular adaptations like an antifreeze protein, but others don’t have the capacity to cope with the warming temperatures. At a molecular level, this situation is related to incapability to express the heat shock proteins which are involved in cellular protection. On the other hand, the relatively high oxygen solubility at cold-sea water temperatures, produce an elevated tissue oxidative stress. In this way, Antarctic marine invertebrates may be detrimental of other marine organisms if they can not express these stress proteins or if they expressed constitutively other proteins associated with stress like antioxidants proteins. The role of these stress proteins is not completely understood in these stenothermal invertebrates because the molecular information is limited and their association is not well known in their physiological mechanism. This proposal will be focused in performing physiological measurements and molecular characterization of the thermal stress response in two Antarctic marine invertebrates (Sterechinus neumayeri and Glyptonotus antarcticus). The aim of this application is to provide explanations of how thermal stress could globally affect the physiological response including metabolism measurements like oxygen consumption,and gene and protein expression linked to thermal stress and antioxidant defense. The specific aims of this proposal are: 1. To perform a physiological measure related to metabolic rate during thermal stress. 2. To carry out an Express Sequence Tag (EST) program of the tissues of the Antarctic sea urchin and isopod. 3. To evaluate the expression patterns of different genes encoding antioxidant enzymes and heat shock proteins (HSP 70 and 90) by qPCR. 4. To evaluate the HSP protein expression and antioxidant enzymes like superoxide dismutase, catalase and NKEF by immunological techniques. In this proposal, we will try to establish if these two key species are capable to over-express the heat shock proteins and antioxidant enzymes in the context of global climate change. In addition, the genome information that will be produced for us will help increase our knowledge about the other genes involved in cold adaptation and stress response in this extreme environment.