Meeting Abstract

79.5  Monday, Jan. 6 11:00  Acclimation to aerial exposure in the long-jawed mudsucker (Gillichthys mirabilis) JEW, CJ*; GRACEY, AY; YANAGITSURU, Y; GRAHAM, JB; TRESGUERRES, M; Scripps Institution of Oceanography, Univ. of California, San Diego; University of Southern California cjjew@uci.edu

The long-jawed mudsucker (Gillichthys mirabilis) is an intertidal wetland goby that frequently experiences aquatic hypoxia and, in response, has been known to gulp air in water or emerge onto land. G. mirabilis is however limited in its terrestrial capacity, having a quiescent behavior out of water and eliciting a similar transcriptional response as aquatic hypoxia. This study aims to test if and how G. mirabilis can acclimate to air-exposure after repeated emersion events. G. mirabilis was exposed to air for eight hours daily over 20 days while control fish were left submerged. On day 21 both groups experienced a hypoxia challenge of 24 hours of emersion. Muscle and liver were sampled from control fish on days 20 and 21 and from experimental fish on day 21 for transcriptomic, metabolomic, and enzymatic assays. During acute air exposure (control day 20 vs. control day 21), metabolomic data showed oxygen limitation of carbohydrate metabolism in the muscle, elevated lipid breakdown in liver, and reduction of protein synthesis in both tissues. Acclimated mudsuckers exposed to air (experimental day 21 vs. control day 21) showed a general blunted effect compared to acute exposure suggesting increased air breathing ability. Transcriptomics data showed similar trends as metabolomic data, however, enzymatic activity showed no change in aerobic (citric synthase) or anaerobic (lactate dehydrogenase) ability. This suggests that G. mirabilis may already be enzymatically poised, in terms of the glycolytic pathway, to deal with the eight hours of air exposure used for the acclimation treatment but were not able to quickly increase the enzyme activity over the hypoxia challenge.