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

Abstract

During their long evolutionary history, jelly sh have faced changes in multiple environmental factors, to which they may selectively x adaptations allowing some species to survive and inhabit diverse environments. Previous ndings have con rmed the jelly sh'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 jelly sh Stomolophus sp2 (previously misidenti ed as Stomolophus meleagris). The isolated mitochondrial oxygen consumption rates, multimeric complexes' in-gel activity, immunodetection, and mass spectrometry identi cation con rmed that the jelly sh mitochondrial respiratory chain contains the ve canonical complexes I to IV and F 0 F 1 -ATP synthase. In addition, our results con rmed 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). Signi cant differences in the transcript abundance of each alternative enzyme from jelly sh transcriptomes were detected after jelly sh were exposed to three different temperatures. These rst-time reported enzymes in cnidarians suggest the mitochondrial adaptative ability allowing jelly sh rapid metabolic responses to maintain energetic homeostasis and to face the temperature variations due to climate change.