Meeting Abstract

48.4  Saturday, Jan. 5  Hemoglobin Gelation in Arcto-Boreal Fishes: To Sickle or not to Sickle? HUNT VON HERBING, Ione*; CASHON , Robert; BABCOCK, Mike; University of North Texas; University of Maine; Dahl-Chase Diagnostic Services vonherbing@unt.edu

Recent observations of red blood cells in teleost fishes have shown the formation of regular paracrystalline arrays of hemoglobin (Hb) tetramers formed under low oxygen conditions in several species of boreal fishes, including Atlantic cod (Gadus morhua) and Atlantic Toadfish (Opsanus tau). This phenomenon is termed hemoglobin gelation and/or sickling. Its physiological characteristics and importance to fish survival is unknown. In the present study, data were obtained on the frequency and physiological nature of the phenomenon of hemoglobin (Hb) of fishes that inhabit cold-water temperate and Arctic environments. More than twenty-seven fish species were examined for the incidence of gelation and of these only the cold-water boreal fishes have exhibited Hb gelation. Evidence for the formation and presence of the paracrystalline Hb matrix in whole red blood cells was provided by optical microscopy, transmission electron microscopy and was supported by in situ observations. Data provided by purification and subsequent polymerization of the Hb extracted from whole blood showed that gelation is an instrinsic property of the Hb, and not dependent on the surrounding intracellular matrix. These findings suggest that gelation is an instrinic property of the Hb and occurs under conditions that are likely to be found in vivo. The scientific relevance of these findings was to determine if there are common morphological and physiological traits among hemoglobins of boreal fishes that exhibit gelation/sickling and whether these traits may be adaptive under the frequent extreme environments characteristic of boreal and polar regions.