Biggar Kyle K, Zhang Jing, Storey Kenneth B
Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada.
The hospital for sick children, Neuroscience and Mental Health, Toronto, Ontario, Canada.
PeerJ. 2019 Nov 26;7:e8144. doi: 10.7717/peerj.8144. eCollection 2019.
The best facultative anaerobes among vertebrates are members of the genera (pond slider turtles) and (painted turtles), and are able to survive without oxygen for up to 12 to 18 weeks at ∼3 °C. In this study, we utilized RNAseq to profile the transcriptomic changes that take place in response to 20 hrs of anoxia at 5 °C in the liver of the red eared slide turtle (). Sequencing reads were obtained from at least 18,169 different genes and represented a minimum 49x coverage of the exome. A total of 3,105 genes showed statistically significant changes in gene expression between the two animal groups, of which 971 also exhibited a fold change equal to or greater than 50% of control normoxic values. This study also highlights a number of anoxia-responsive molecular pathways that are may be important to navigating anoxia survival. These pathways were enriched in mRNA found to significantly increase in response to anoxia and included molecular processes such as DNA damage repair and metabolic reprogramming. For example, our results indicate that the anoxic turtle may utilize succinate metabolism to yield a molecule of GTP in addition to the two molecules that results from lactate production, and agrees with other established models of anoxia tolerance. Collectively, our analysis provides a snapshot of the molecular landscape of the anoxic turtle and may provide hints into the how this animal is capable of surviving this extreme environmental stress.
脊椎动物中最佳的兼性厌氧菌是锦龟属（滑龟）和彩龟属（彩龟）的成员，它们能够在约3°C的无氧环境中存活长达12至18周。在本研究中，我们利用RNA测序来描绘红耳滑龟肝脏在5°C下缺氧20小时后发生的转录组变化。测序读数来自至少18,169个不同的基因，代表了滑龟外显子组至少49倍的覆盖度。共有3,105个基因在两组动物之间表现出具有统计学意义的基因表达变化，其中971个基因的变化倍数也等于或大于对照常氧值的50%。本研究还突出了一些对缺氧有反应的分子途径，这些途径可能对指导缺氧生存很重要。这些途径在对缺氧有显著增加反应的mRNA中富集，包括DNA损伤修复和代谢重编程等分子过程。例如，我们的结果表明，缺氧的乌龟除了通过乳酸生成产生两个分子外还可能利用琥珀酸代谢产生一个GTP分子，这与其他已建立的缺氧耐受模型一致。总的来说，我们的分析提供了缺氧乌龟分子图景的快照，并可能为了解这种动物如何能够在这种极端环境压力下生存提供线索。
