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Abstract |
Polar Regions suffer first the effects of global warming. In Antarctica, the Peninsula region already undergoes a seawater elevation of temperature of 1°C, and in the Arctic, sea ice cover is decreasing due to an enhanced input of warm Atlantic waters. In that context, assessment of the physiological impact of a potential increase in temperature on polar species is a priority in term of biodiversity management. Euphausiids (krill) constitute keystone species in the Antarctic and Arctic trophic chains and feed zooplankton as well as large carnivorous mammals and birds. The physiological response of krill (i.e Euphausia superba , E. crystallorophias and Thysanoessa inermis) facing an increase in ocean temperature is then a primordial marker to predict evolution of polar animal communities. An approach combining animals conditioning on the field and transcriptomic has been implemented to study molecular capacities to respond to heat stress. So, CTmax have first been estimated with each species. Then, to characterise the molecular response, heat shock proteins (HSPs) have been chosen at first sight as molecular marker for their chaperoning role in thermal stress response. The high-throughput sequencing (Illumina) permitted to identify, members of HSP family in the three species, focusing on HSP70. Quantitative PCR is used to quantify HSP70 isoforms expression levels, after an artificial heat stress, in order to establish species stress tolerance. |
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