Antifreeze Activity in Temperate Fish from the East Sea, Korea

Abstract

Antifreeze proteins and glycoproteins [AF(G)Ps] constitute a group of proteins that lower the freezing but not the melting points of aqueous solutions, enabling polar and north-temperate fish to survive in ice-laden environments. However, little is known about antifreeze activity in temperate fish; such work would extend our knowledge on the functions and evolution of AF(G)Ps. In the present study, we screened for antifreeze activity in temperate fish caught off the coast of Jumunjin (37.89°N), Gangneung, Korea. Thermal hysteresis (TH) and the ability to inhibit ice recrystallization (IR) in blood, liver, and muscle samples from nine fish were examined to assess antifreeze activity. As the East Sea off the coast of Jumunjin is ice-free year round, we thought it most unlikely that the fish would express antifreeze proteins. Surprisingly, the blood of Pleurogrammus azonus and three types of tissue from Gymnocanthus herzensteini, Zoarces gilli and Kareius bicoloratus exhibited measurable TH values together with the ability to trigger characteristic morphological changes in ice crystals. Blood samples from the three species also evidenced ice recrystallization (IR) inhibition. This implies that AF(G)Ps or other antifreeze-like substances are present in temperate fish even under nonfreezing conditions. These results contribute to our understanding of the functions and origins of antifreeze activity in fish.

Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus)

“…Conversely, it is not likely that temperate and/ or subtropical fish require antifreeze activity for survival. However, contrary to our expectation, we observed antifreeze activity in some temperate and subtropical fish from the ice-free East Sea of Korea (Kim 2015). Among nine fish examined in that region, three fish, Gymnocanthus herzensteini, Zoarces gillii, and Kareius bicoloratus, exhibited antifreeze activity.…”

“…In addition, P. olivaceus did not initially demonstrate an antifreeze activity (Kim 2015). However, its EST analysis revealed that it carried a transcribable afp4 gene, which further raised the question of the function of this transcript.…”

“…Recently, AFPs and antifreeze activity have also been reported from fish living in regions other than polar regions such as north-temperate and temperate areas (Deng et al 1997;Gauthier et al 2008;Nishimiya et al 2008;Kim 2015). Conventionally, north-temperate fish off the east coast (50°N) of Canada and/or Hokkaido (43.06°N) have been suggested to possess AFPs as a result of convergent evolution (Cheng 1998;Cheng and Chen 1999;Cheng 1998;Cheng et al 2003;Graham et al 2008Graham et al , 2013, as sea ice forms in these coastal areas during winter similar to that in the austral winter at the Antarctic.…”

Molecular Characterization and mRNA Expression of ISP2 and ISP4 in the Large Yellow Croaker (Larimichthys Crocea) Under Acute Cold Stress

“…Based on these ndings, Gauthier et al (2008) speculated that ISP4 may not be a key antifreeze protein in the blood of polar sh when other types of antifreeze protein are present. Surprisingly, in addition to polar sh, ISP4 is also found in warm-temperate sh and freshwater sh (Nishimiya et al, 2008;Zhang et al, 2009;Kim, 2015;Lee and Kim, 2016). These reports indicate that ISP4 may have other effects as well as antifreeze activity in warm-temperate sh.…”