Thermal variations due to global climate change are expected to modify the distributions of marine ectotherms, with potential pathogen translocations. This is of particular concern at high latitudes where cold-adapted stenothermal fish such as the Notothenioids occur. However, little is known about the combined effects of thermal fluctuations and immune challenges on the balance between cell damage and repair processes in these fish. The aim of this study was to determine the effect of thermal variation on specific genes involved in the ubiquitination and apoptosis pathways in two congeneric Notothenioid species, subjected to simulated bacterial and viral infections. Adult fish of Harpagifer bispinis and Harpagifer antarcticus were collected from Punta Arenas (Chile) and King George Island (Antarctica), respectively, and distributed as follows: injected with PBS (control), LPS (2.5 mg/kg) or Poly I:C (2 mg/kg) and then submitted to 2, 5 and 8 °C. After 1 week, samples of gills, liver and spleen were taken to evaluate the expression by real-time PCR of specific genes involved in ubiquitination (E3-ligase enzyme) and apoptosis (BAX and SMAC/DIABLO). Gene expression was tissue-dependent and increased with increasing temperature in the gills and liver while showing an opposite pattern in the spleen. Studying a pair of sister species that occur across the Antarctic Polar Front can help us understand the particular pressures of intertidal lifestyles and the effect of temperature in combination with biological stressors on cell damage and repair capacity in a changing environment.

全球气候变化引起的热变化预计将改变海洋变温带的分布，并可能导致病原体易位。这在高纬度地区尤其令人担忧，因为那里出现了适应寒冷的窄温鱼，例如Notothenioids。然而，人们对热波动和免疫挑战对这些鱼细胞损伤和修复过程之间平衡的综合影响知之甚少。本研究的目的是确定热变化对参与模拟细菌和病毒感染的两种同属 Notothenioids 物种的泛素化和凋亡途径的特定基因的影响。分别从蓬塔阿雷纳斯（智利）和乔治王岛（南极洲）收集Harpagifer bispinis和Harpagifer antarcticus成鱼，并按如下方式分配：注射 PBS（对照）、LPS（2.5 mg/kg）或 Poly I:C (2 mg/kg)，然后置于 2、5 和 8 °C。 1周后，采集鳃、肝脏和脾脏样本，通过实时PCR评估涉及泛素化（E3-连接酶）和细胞凋亡（BAX和SMAC/DIABLO）的特定基因的表达。基因表达具有组织依赖性，并且随着鳃和肝脏温度的升高而增加，而在脾脏中则表现出相反的模式。研究出现在南极极锋的一对姐妹物种可以帮助我们了解潮间带生活方式的特殊压力，以及温度与生物应激源相结合对不断变化的环境中细胞损伤和修复能力的影响。