helgead

• Lau, Gigi Yik Chee; Gerber, Lucie; Johansen, Anette; Dahl, Helge Andre; Torp, May-Kristin & Bates, Georgina [Show all 11 contributors for this article] (2026). Mitochondrial responses to anoxia-reoxygenation exposure in crucian carp (Carassius carassius). Journal of Experimental Biology. ISSN 0022-0949. 229(4). doi: 10.1242/jeb.251839. Full text in Research Archive
• Dahl, Helge-Andre; Johansen, Anette; Nilsson, Göran Erik & Lefevre, Sjannie (2021). The Metabolomic Response of Crucian Carp (Carassius carassius) to Anoxia and Reoxygenation Differs between Tissues and Hints at Uncharacterized Survival Strategies. Metabolites. 11(7), p. 1–26. doi: 10.3390/metabo11070435. Full text in Research Archive Show summary

  The anoxia-tolerant crucian carp (Carassius carassius) has been studied in detail for numerous years, with particular focus on unravelling the underlying physiological mechanisms of anoxia tolerance. However, relatively little work has been focused on what occurs beyond anoxia, and often the focus is a single organ or tissue type. In this study, we quantified more than 100 metabolites by capillary electrophoresis-mass spectrometry (CE-MS) in brain, heart, liver, and blood plasma from four experimental groups, being normoxic (control) fish, anoxia-exposed fish, and two groups that had been exposed to anoxia followed by reoxygenation for either 3 h or 24 h. The heart, which maintains cardiac output during anoxia, unexpectedly, was slower to recover compared to the brain and liver, mainly due to a slower return to control concentrations of the energy-carrying compounds ATP, GTP, and phosphocreatine. Crucian carp accumulated amino acids in most tissues, and also surprisingly high levels of succinate in all tissues investigated during anoxia. Purine catabolism was enhanced, leading to accumulation of uric acid during anoxia and increasing urea formation that continued into 24 h of reoxygenation. These tissue-specific differences in accumulation and distribution of the metabolites may indicate an intricate system of transport between tissues, opening for new avenues of investigation of possible mechanisms aimed at reducing the generation of reactive oxygen species (ROS) and resultant tissue damage during reoxygenation.

• Malecki, Jedrzej Mieczyslaw; Dahl, Helge-Andre; Moen, Anders; Davydova, Erna & Falnes, Pål (2016). The METTL20 homologue from agrobacterium tumefaciens is a dual specificity protein-lysine methyltransferase that targets ribosomal protein L7/L12 and the β subunit of electron transfer flavoprotein (ETFβ). Journal of Biological Chemistry. ISSN 0021-9258. 291(18), p. 9581–9595. doi: 10.1074/jbc.M115.709261. Full text in Research Archive
• Malecki, Jedrzej Mieczyslaw; Ho, Angela Yeuan Yen; Moen, Anders; Dahl, Helge-Andre & Falnes, Pål (2015). Human METTL20 is a mitochondrial lysine methyltransferase that targets the β subunit of electron transfer flavoprotein (ETFβ) and modulates its activity. Journal of Biological Chemistry. ISSN 0021-9258. 290(1), p. 423–434. doi: 10.1074/jbc.M114.614115. Full text in Research Archive

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• Lefevre, Sjannie; Dahl, Helge Andre; Williams, Darryl; Jentoft, Sissel & Cossins, Andrew R. (2024). Changes in transcription-translation dynamics in crucian carp brain revealed by Riboseq. Full text in Research Archive Show summary

  The physiological adaptations allowing the crucian carp (Carassius carassius) to survive anoxia are well characterised. At the whole-animal level, these adaptations are well understood, but we know less about the cellular and molecular mechanisms involved in regulating the response to anoxia. Genes, through their transcription and translation to protein products, are (assumingly) central to molecular, cellular and ultimately tissue function. A timely and appropriate change in gene expression is expected to coordinate the more long-term physiological responses to anoxia, and next-generation sequencing techniques and bioinformatics can provide is a global view of these changes. While it is reasonable to assume that changes in gene expression for a majority of genes leads to matching changes in translation and synthesis of proteins, the picture and conclusions that can be drawn will be more complete by looking not only at gene expression but also translation. By sequencing and quantifying both mRNA and ribosome-protected mRNA fragments (RPFs) in brain tissue from crucian carp exposed to normoxia, anoxia and re-oxygenation, we can determine the genes that are differentially expressed, as well as the degree to which the changes in mRNA expression lead to a change in translation. We can also assess whether changes in expression of RPFs are the result of altered transcription or altered translation efficiency. The data so far reveal that translation efficiency for some genes changes more rapidly than transcription in response to anoxia and particularly re-oxygenation, giving the crucian carp finer temporal control of the protein pool and hence cellular activities.

• Lefevre, Sjannie & Dahl, Helge Andre (2022). Insights from ‘omics’ about crucian carp anoxia tolerance. Full text in Research Archive Show summary

  The crucian carp (Carassius carassius) is extremely tolerant to the absence of oxygen. Its metabolically most active organs, such as the brain, can maintain function over extended periods of anoxia. Our research seeks to understand the cellular and molecular mechanisms involved in regulating the response of the crucian carp to anoxia. We take a discovery-driven approach, using metabolomics, transcriptomics and translatomics, to identify key mechanisms and signalling pathways behind the extreme anoxia tolerance. In this talk, I will present results on sequencing and quantification of mRNA and ribosome-protected (i.e. translated) mRNA fragments in brain tissue from crucian carp exposed to normoxia, anoxia and re-oxygenation, as well as metabolites from multiple tissues.

• Gerber, Lucie; Helle-Valle, Tellef; Resseguier, Julien Alain Andre; Torp, May-Kristin; Dahl, Helge Andre & Nilsson, Göran Erik [Show all 8 contributors for this article] (2022). Prolyl Hydroxylase Domains in the Anoxia Tolerant Crucian Carp (c. carassius): Insights into the Regulation of the HIF Response to Anoxia-Reoxygenation. Full text in Research Archive
• Gerber, Lucie; Helle-Valle, Tellef; Resseguier, Julien Alain Andre; Torp, May-Kristin; Dahl, Helge Andre & Nilsson, Göran Erik [Show all 8 contributors for this article] (2022). Prolyl Hydroxylase Domains in the Anoxia Tolerant Crucian Carp (c. carassius): Insights into the Regulation of the HIF Response to Anoxia-Reoxygenation. Full text in Research Archive
• Lefevre, Sjannie; Lau, Gigi Yik Chee; Dahl, Helge-Andre & Nilsson, Göran Erik (2019). Crucian carp: mitochondria, anoxia and reoxygenation. Full text in Research Archive
• Lefevre, Sjannie; Lau, Gigi Yik Chee; Dahl, Helge-Andre & Nilsson, Göran Erik (2019). Re-oxygenation resilience - the other aspect of the crucian carp’s anoxia tolerance. Full text in Research Archive
• Dahl, Helge-Andre & Lefevre, Sjannie (2018). Protection against reperfusion injury: can insight be gained from crucian carp? Full text in Research Archive

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