Meeting Abstract
P2.130 Sunday, Jan. 5 15:30 Hydrogen sulfide signaling in the hypoxia responses of the Atlantic blue crab DEREX, RL*; BURNETT, KG; BURNETT, LE; College of Charleston; College of Charleston; College of Charleston derexrl@g.cofc.edu
Across many animal phyla, responses to environmental hypoxia can be observed at the behavioral, organ system, molecular, and biochemical levels. Brachyuran crustaceans exhibit altered ventilation patterns that correlate to hemolymph O2 tensions, supporting the existence of a cellular O2 sensor that activates hypoxia-response signaling pathways. Recent studies implicate H2S as a putative signal that mediates the global response to hypoxia in all vertebrate classes, and it has been demonstrated that invertebrates produce H2S via the same enzymatic pathways. We are interested in seeing if H2S production influences the ventilatory patterns produced by exposure to hypoxia in the Atlantic blue crab, Callinectes sapidus. The frequency (fbeat) and bilaterality of scaphognathite beating, and the frequency (fpause) and duration (Tpause) of ventilatory pauses, were measured in crabs acutely exposed to hypoxia (10.0 and 6.7 kPa) or to H2S (10, 25, and 100 mM) under normoxic conditions. We found fbeat increases with hypoxia (77.1 BPM±15.7SEM, 103.0±5.4, and 122.8±7.1 in 20.6, 10.0, and 6.7 kPa, respectively), while fpause and Tpause are greatly reduced in hypoxia. Injections of H2S into the branchial chamber transiently increase ventilation rates, and normal ventilation patterns resume seconds after completion of H2S injections. In vivo inhibition of H2S-producing enzymes did not reduce changes in ventilatory patterns under hypoxia, although we have not yet confirmed that this inhibition was successful. Future objectives include quantifying changes in the gene transcripts and enzymatic activity of the H2S-producing enzymes in crabs exposed to normoxia or chronic hypoxia. Evaluating the potential for H2S to act as a signal will provide valuable insight to the mechanisms underlying crustacean O2 sensing. (NSF IOS-1147008)
