TY - JOUR
T1 - Effects of warming rates on physiological and molecular components of response to CTMax heat stress in the Antarctic fish Harpagifer antarcticus
AU - Saravia, Julia
AU - Paschke, Kurt
AU - Oyarzún-Salazar, Ricardo
AU - Cheng, C. H.Christina
AU - Navarro, Jorge M.
AU - Vargas-Chacoff, Luis
N1 - Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/7
Y1 - 2021/7
N2 - Maximum and minimum Critical thermal limits (CTMax and CTMin) have been studied extensively to assess thermal tolerance in ectotherms by means of ramping assays. Notothenioid fish have been proposed as particularly sensitive to temperature increases related to global climate change. However, there are large gaps in our understanding of the thermal responses of these extreme cold-adapted fish in assays with heating rates. We evaluated the effects of two commonly used heating rates (0.3 and 1 °C/min) on the cellular stress responses in the intertidal Antarctic fish Harpagifer antarcticus immediately after CTMax was reached, and at 2 and 4 h of recovery time in ambient water. We compared CTMax values, the relative transcript expression of genes relvant to heat shock response (Hsc70, Hsp70, Grp78), hypoxia (Hif1-α, LDHa, GR), ubiquitination (Ube2), and apoptosis (SMAC/DIABLO), and five plasma parameters - glucose, lactate, total protein, osmolality and cortisol. CTMax values between the two heating rates are not significantly different, and both rates elicited a similar stress response at molecular and physiological levels. We found a lack of up-regulated response of heat shock proteins, consistent with other Antarctic notothenioids. The general transcriptional pattern trended to downregulation, which was more evident in the slower 0.3 °C/min rate, and instances of upregulation were mainly related to ubiquitination. The faster 1 °C/min rate, rarely used for Antarctic fish, can be suitable for studying cold-adapted stenothermic fish without overestimating thermal tolerance or inducing damage from longer heat exposure.
AB - Maximum and minimum Critical thermal limits (CTMax and CTMin) have been studied extensively to assess thermal tolerance in ectotherms by means of ramping assays. Notothenioid fish have been proposed as particularly sensitive to temperature increases related to global climate change. However, there are large gaps in our understanding of the thermal responses of these extreme cold-adapted fish in assays with heating rates. We evaluated the effects of two commonly used heating rates (0.3 and 1 °C/min) on the cellular stress responses in the intertidal Antarctic fish Harpagifer antarcticus immediately after CTMax was reached, and at 2 and 4 h of recovery time in ambient water. We compared CTMax values, the relative transcript expression of genes relvant to heat shock response (Hsc70, Hsp70, Grp78), hypoxia (Hif1-α, LDHa, GR), ubiquitination (Ube2), and apoptosis (SMAC/DIABLO), and five plasma parameters - glucose, lactate, total protein, osmolality and cortisol. CTMax values between the two heating rates are not significantly different, and both rates elicited a similar stress response at molecular and physiological levels. We found a lack of up-regulated response of heat shock proteins, consistent with other Antarctic notothenioids. The general transcriptional pattern trended to downregulation, which was more evident in the slower 0.3 °C/min rate, and instances of upregulation were mainly related to ubiquitination. The faster 1 °C/min rate, rarely used for Antarctic fish, can be suitable for studying cold-adapted stenothermic fish without overestimating thermal tolerance or inducing damage from longer heat exposure.
KW - Ectotherms
KW - Global climate change
KW - Physiology
KW - Plunder fish
KW - mRNA
UR - http://www.scopus.com/inward/record.url?scp=85107430035&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85107430035&partnerID=8YFLogxK
U2 - 10.1016/j.jtherbio.2021.103021
DO - 10.1016/j.jtherbio.2021.103021
M3 - Article
C2 - 34420652
AN - SCOPUS:85107430035
SN - 0306-4565
VL - 99
JO - Journal of Thermal Biology
JF - Journal of Thermal Biology
M1 - 103021
ER -