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OXPHOS capacity is diminished and the phosphorylation system inhibited during diapause in an extremophile, embryos of Artemia franciscana.
Patil, Yuvraj N; Gnaiger, Erich; Landry, Alexander P; Leno, Zachary J; Hand, Steven C.
Afiliación
  • Patil YN; Department of Biological Sciences, Division of Cellular, Developmental and Integrative Biology, Louisiana State University, Baton Rouge, LA 70803, USA.
  • Gnaiger E; Oroboros Instruments GmbH, 6020 Innsbruck, Austria.
  • Landry AP; Department of Biological Sciences, Division of Cellular, Developmental and Integrative Biology, Louisiana State University, Baton Rouge, LA 70803, USA.
  • Leno ZJ; Department of Biological Sciences, Division of Cellular, Developmental and Integrative Biology, Louisiana State University, Baton Rouge, LA 70803, USA.
  • Hand SC; Department of Biological Sciences, Division of Cellular, Developmental and Integrative Biology, Louisiana State University, Baton Rouge, LA 70803, USA.
J Exp Biol ; 227(2)2024 01 15.
Article en En | MEDLINE | ID: mdl-38099471
ABSTRACT
Diapause exhibited by embryos of Artemia franciscana is accompanied by severe arrest of respiration. A large fraction of this depression is attributable to downregulation of trehalose catabolism that ultimately restricts fuel to mitochondria. This study now extends knowledge on the mechanism by revealing metabolic depression is heightened by inhibitions within mitochondria. Compared with that in embryo lysates during post-diapause, oxidative phosphorylation (OXPHOS) capacity P is depressed during diapause when either NADH-linked substrates (pyruvate and malate) for electron transfer (electron transfer capacity, E) through respiratory Complex I or the Complex II substrate succinate are used. When pyruvate, malate and succinate were combined, respiratory inhibition by the phosphorylation system in diapause lysates was discovered as judged by P/E flux control ratios (two-way ANOVA; F1,24=38.78; P<0.0001). Inhibition was eliminated as the diapause extract was diluted (significant interaction term; F2,24=9.866; P=0.0007), consistent with the presence of a diffusible inhibitor. One candidate is long-chain acyl-CoA esters known to inhibit the adenine nucleotide translocator. Addition of oleoyl-CoA to post-diapause lysates markedly decreased the P/E ratio to 0.40±0.07 (mean±s.d.; P=0.002) compared with 0.79±0.11 without oleoyl-CoA. Oleoyl-CoA inhibits the phosphorylation system and may be responsible for the depressed P/E in lysates from diapause embryos. With isolated mitochondria, depression of P/E by oleoyl-CoA was fully reversed by addition of l-carnitine (control versus recovery with l-carnitine, P=0.338), which facilitates oleoyl-CoA transport into the matrix and elimination by ß-oxidation. In conclusion, severe metabolic arrest during diapause promoted by restricting glycolytic carbon to mitochondria is reinforced by depression of OXPHOS capacity and the phosphorylation system.
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Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Extremófilos / Diapausa Límite: Animals Idioma: En Revista: J Exp Biol Año: 2024 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Extremófilos / Diapausa Límite: Animals Idioma: En Revista: J Exp Biol Año: 2024 Tipo del documento: Article País de afiliación: Estados Unidos