Meeting Abstract
P2.106 Wednesday, Jan. 5 Differential hypoxia tolerance and AMPK activity in two color morphs of the green crab, Carcinus maenas TOOMBS, C.A.*; JOST, J.A.; FREDERICH, M.; Univ. of New England, Biddeford; Univ. of New England, Biddeford; Univ. of New England, Biddeford mfrederich@une.edu
Carcinus maenas is an invasive species in intertidal habitats and occurs in a green and a red color morph. Earlier studies suggest that the green morph is more tolerant to stress than the red morph, but the cellular mechanism of that difference is still unclear. Recent studies show that in different species energy metabolism is regulated during stress by the enzyme AMP-activated protein kinase, AMPK. It is unknown whether AMPK plays a role in the differential stress tolerance of the two morphs. We tested the hypothesis that the discrepancy in stress tolerance is reflected in differential AMPK activity. Red and green morphs were exposed to anoxia (<0.3mg/dl O2) for 2h, or to hypoxia (1.7mg/dl O2) for 24h. We analyzed motor activity, heart rate, lactate accumulation, AMPK activity and mRNA expression, and HSP70 in heart tissue. During anoxia all animals showed a progressive decrease in reaction time and heart rate. More importantly, the green morph, compared to the red, accumulated more lactate (p<0.05), had higher AMPK activity (p<0.05), but similar HSP70 protein levels. Additionally, after 24h hypoxia the green morphs had higher AMPK activity than the red (p<0.05) and similar HSP70 levels. During normoxia green morphs used more oxygen than the red morphs (p<0.05). This contradicts earlier publications, which describe green morphs as being more tolerant to stress and using less oxygen. Our data confirm AMPK as a cellular marker for stress in crabs, and provide evidence for physiological differences at the cellular level between the color morphs. Elucidating the detailed physiology of this species is important for understanding how this species could become such a successful invader and might be applied to other invasive species. Funded by NSF-IOB0640478.
