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International audience; The Alps are a hotspot of biodiversity in Europe with many Lepidoptera species still to be discovered. Here we describe a new gracillariid genus and species, Mercantouria neli gen. n. and sp. n. The morphology of the male genitalia is highly differentiated with unique features. DNA barcodes show that its nearest neighbor is the North American species ‘Caloptilia’ scutellariella (Braun, 1923). M. neli is known from four adults (two males and two females) collected at two localities in the French Alps. Its host plant and life cycle remain unknown.

We studied the interaction between energy metabolism and mitochondrial biogenesis during myogenesis in C2C12 myoblasts. Metabolic rate was nearly constant throughout differentiation, although there was a shift in the relative importance of glycolytic and oxidative metabolism, accompanied by increases in pyruvate dehydrogenase activation state and total activity. These changes in mitochondrial bioenergetic parameters observed during differentiation occurred in the absence of a hypermetabolic stress. A chronic (3 day) energetic stress was imposed on differentiated myotubes using sodium azide to inhibit oxidative metabolism. When used at low concentrations, azide inhibited more than 70% of cytochrome oxidase (COX) activity without changes in bioenergetics (either lactate production or creatine phosphorylation) or mRNA for mitochondrial enzymes. Higher azide concentrations resulted in changes in bioenergetic parameters and increases in steady state COX II mRNA levels. Azide did not affect mtDNA copy number or mRNA levels for other mitochondrial transcripts, suggesting azide affects stability, rather than synthesis, of COX II mRNA. These results indicate that changes in bioenergetics can alter mitochondrial genetic regulation, but that mitochondrial biogenesis accompanying differentiation occurs in the absence of hypermetabolic challenge.

Phosphorylation of respiratory chain components has emerged as a mode of regulation of mitochondrial energy metabolism, but its mechanisms are still largely unexplored. A recently discovered intramitochondrial signalling pathway links CO(2) generated by the Krebs cycle with the respiratory chain, through the action of a mitochondrial soluble adenylyl cyclase (mt-sAC). Cytochrome oxidase (COX), whose deficiency causes a number of fatal metabolic disorders, is a key mitochondrial enzyme activated by mt-sAC. We have now discovered that the mt-sAC pathway modulates mitochondrial biogenesis in a reactive oxygen species dependent manner, in cultured cells and in animals with COX deficiency. We show that upregulation of mt-sAC normalizes reactive oxygen species production and mitochondrial biogenesis, thereby restoring mitochondrial function. This is the first example of manipulation of a mitochondrial signalling pathway to achieve a direct positive modulation of COX, with clear implications for the development of novel approaches to treat mitochondrial diseases.