Meeting Abstract

P2.177  Monday, Jan. 5  Differential response of AMP activated protein kinase (AMPK) and HSP70 to temperature stress in a gastropod ZIMMERMANN, Emily *; DIONNE, Megan; FREDERICH, Markus; YUND, Philip O.; U. of New England; U. of New England; U. of New England; U. of New England ezimmermann@mail.une.edu

Nucella lapillus is a common gastropod in rocky intertidal habitats of the North Atlantic. Populations are polymorphic for shell color, with light-colored shells predominating on warmer, wave-protected shores and dark-colored shells limited primarily to cooler, wave-exposed shores. Color morphs exhibit differential heating during thermal stress, with darker shells attaining higher body temperatures than lighter shells. These results suggest that heat stress may determine field distribution patterns. However, there is currently little evidence of physiological consequences of thermal stress in these organisms. Following the guiding hypothesis that heat stress leads to cellular energy depletion, we explored whether AMPK is activated by heat stress, and compared this response in both color morphs to the expression of a heat shock protein (Hsp70). Hsp70 is widely used as an indicator of thermal stress, but it can also be induced by other stressors. AMPK is a central energy regulator in mammals that activates ATP-generating catabolic pathways and inactivates ATP-consuming anabolic pathways. Though AMPK is highly conserved during evolution, it has rarely been studied in invertebrates. Two color morphs of snails were tethered to a rock, exposed to varying levels of heat stress (within the range known to occur regularly in the field), and sampled at three time points. AMPK activity increased earlier and at lower temperatures than HSP, and was higher in dark vs. light color morphs. Furthermore, AMPK activity had decreased by the onset of HSP expression. Our results suggest that AMPK may be an early indicator of thermal stress in gastropods, and a useful tool for studying thermal stress in the field.