Meeting Abstract

10.1  Monday, Jan. 4  Salinity acclimation in sea snakes: A comparison of specialized and unspecialized cephalic glands BABONIS, L.S.*; EVANS, D.H.; Univ. of Florida; Univ. of Florida babonis@ufl.edu

Laticaudine sea snakes experience frequent fluctuations in environmental salinity, making them valuable models for studies of salt gland (SG) function. Though the SG is known to function primarily in osmoregulation, little is known about the osmoregulatory capacity of other cephalic secretory glands. The functional difference between SGs and other cephalic secretory glands may derive from the abundance/distribution of ion transporters like Na⁺/K⁺-ATPase (NKA), Na⁺/K⁺/2Cl^– cotransporter (NKCC), and cystic fibrosis transmembrane conductance regulator (CFTR). After 7 days in 100% seawater (SW; time 0) we acclimated sea snakes (Laticauda semifasciata) to 0, 50 or 100% SW (n = 6 per treatment) for 14 days. We then compared the abundance/distribution of NKA, NKCC, and CFTR in the SG and the (unspecialized) Harderian gland (HG) across treatments. As HGs are not known to be involved in osmoregulation, we expected expression of NKA, NKCC, and CFTR to be low in all treatments. In contrast, NKA, NKCC, and CFTR were expected to show greater expression in the SG from 100% SW animals than either 50% or 0% SW animals. Using quantitative real-time PCR, we found expression of NKA to be higher in the SG in all treatments than it was in the HG. Additionally, in the SG, expression of all genes was highest in the control group (100% SW, time 0) and decreased in all remaining groups. Expression of NKCC and CFTR did not vary with salinity in the HG but decreased with increasing salinity in the SG. These results suggest that the osmoregulatory capacity of the SG may lie in the overall abundance/response of NKA to variations in salinity. This research was funded by the National Science Foundation (IOB-0519579 to DHE and EAPSI to LSB).