The branched mitochondrial respiratory chain from the jellyfish Stomolophus sp2 as an adaptive response to environmental changes

Abstract

Abstract During their long evolutionary history, jellyfish have faced changes in multiple environmental factors, to which they may selectively fix adaptations allowing some species to survive and inhabit diverse environments. Previous findings have confirmed the jellyfish’s ability to synthesize large ATP amounts, mainly produced by mitochondria, in response to environmental challenges. This study characterized the respiratory chain from the mitochondria of the jellyfish Stomolophus sp2 (previously misidentified as Stomolophus meleagris). The isolated mitochondrial oxygen consumption rates, multimeric complexes’ in-gel activity, immunodetection, and mass spectrometry identification confirmed that the jellyfish mitochondrial respiratory chain contains the five canonical complexes I to IV and F0F1-ATP synthase. In addition, our results confirmed the occurrence of four alternative enzymes integrated into a branched mitochondrial respiratory chain of Stomolophus sp2: an alternative oxidase and three dehydrogenases (two NADH type II enzymes and a mitochondrial glycerol-3-phosphate dehydrogenase). Significant differences in the transcript abundance of each alternative enzyme from jellyfish transcriptomes were detected after jellyfish were exposed to three different temperatures. These first-time reported enzymes in cnidarians suggest the mitochondrial adaptative ability allowing jellyfish rapid metabolic responses to maintain energetic homeostasis and to face the temperature variations due to climate change.