Wang Jing-Yan, Zhang Li-Hua, Hong Yue-Huan, Cai Ling-Na, Storey Kenneth B, Zhang Jia-Yong, Zhang Shu-Sheng, Yu Dan-Na
College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China.
Taishun County Forestry Bureau, Wenzhou 325000, China.
Animals (Basel). 2023 Sep 25;13(19):3015. doi: 10.3390/ani13193015.
Unusual climates can lead to extreme temperatures. , one of the most prevalent anurans in the paddy fields of tropical and subtropical regions in Asia, is sensitive to climate change. The present study focuses primarily on a single question: how do the 13 mitochondrial protein-coding genes (PCGs) respond to extreme temperature change compared with 25 °C controls? Thirty-eight genes including an extra tRNA-Met gene were identified and sequenced from the mitochondrial genome of . Evolutionary relationships were assessed within the Dicroglossidae and showed that Dicroglossinae is monophyletic and is a sister group to the clade of ( + ). Transcript levels of mitochondrial genes in liver were also evaluated to assess responses to 24 h exposure to low (2 °C and 4 °C) or high (40 °C) temperatures. Under 2 °C, seven genes showed significant changes in liver transcript levels, among which transcript levels of , , , , , and increased, respectively, and decreased. However, exposure to 4 °C for 24 h was very different in that the expressions of ten mitochondrial protein-coding genes, except , and , were significantly downregulated. Among them, the transcript level of was most significantly downregulated, decreasing by 0.28-fold. Exposure to a hot environment at 40 °C for 24 h resulted in a marked difference in transcript responses with strong upregulation of eight genes, ranging from a 1.52-fold increase in to a 2.18-fold rise in transcript levels, although and were reduced to 0.56 and 0.67, respectively, compared with the controls. Overall, these results suggest that at 4 °C, appears to have entered a hypometabolic state of hibernation, whereas its mitochondrial oxidative phosphorylation was affected at both 2 °C and 40 °C. The majority of mitochondrial PCGs exhibited substantial changes at all three temperatures, indicating that frogs such as that inhabit tropical or subtropical regions are susceptible to ambient temperature changes and can quickly employ compensating adjustments to proteins involved in the mitochondrial electron transport chain.
异常气候会导致极端温度。泽蛙是亚洲热带和亚热带地区稻田中最常见的无尾目动物之一，对气候变化很敏感。本研究主要聚焦于一个问题：与25°C的对照组相比，13个线粒体蛋白质编码基因（PCGs）如何应对极端温度变化？从泽蛙的线粒体基因组中鉴定并测序了包括一个额外的tRNA-Met基因在内的38个基因。评估了叉舌蛙科内部的进化关系，结果表明叉舌蛙亚科是单系的，泽蛙是（倭蛙属+姬蛙属）分支的姐妹群。还评估了肝脏中线粒体基因的转录水平，以评估对24小时暴露于低温（2°C和4°C）或高温（40°C）的反应。在2°C下，七个基因的肝脏转录水平出现显著变化，其中，泽蛙ND1、ND2、COX1、ATP8、ATP6和CYTB的转录水平分别升高，而ND5降低。然而，暴露于4°C 24小时的情况则大不相同，除了ND4、ND6和CYTB外，十个线粒体蛋白质编码基因的表达均显著下调。其中，ND1的转录水平下调最为显著，下降了0.28倍。暴露于40°C的炎热环境24小时导致转录反应有显著差异，八个基因强烈上调，从ND2转录水平增加1.52倍到CYTB转录水平上升2.18倍，尽管与对照组相比，ND4和ND6分别降至0.56和0.67。总体而言，这些结果表明，在4°C时，泽蛙似乎进入了冬眠的低代谢状态，而其线粒体氧化磷酸化在2°C和40°C时均受到影响。大多数线粒体PCGs在所有三个温度下都表现出显著变化，这表明像泽蛙这样栖息在热带或亚热带地区的青蛙易受环境温度变化的影响，并且可以迅速对参与线粒体电子传递链的蛋白质进行补偿性调整。
