{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T16:26:15Z","timestamp":1783441575615,"version":"3.54.6"},"posted":{"date-parts":[[2026,7,3]]},"group-title":"Evolutionary Biology","reference-count":86,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T00:00:00Z","timestamp":1783036800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"U.S. National Science Foundation","doi-asserted-by":"crossref","award":["IOS-1750322"],"award-info":[{"award-number":["IOS-1750322"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,7,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  Redox balance is central to aerobic metabolism, yet acute heat stress can destabilize this balance by increasing metabolic rates and shifting the balance of critical electron carriers such as NADH. In early\n                  <jats:italic>Drosophila melanogaster<\/jats:italic>\n                  embryos, maintaining redox balance is particularly critical as embryos undergo a developmental redox shift and rely on oxidative phosphorylation to power nuclear divisions. Here, we assayed six isofemale\n                  <jats:italic>D. melanogaster<\/jats:italic>\n                  lines from temperate (Vermont, USA; France; Japan) and tropical (St. Kitts; Ghana; India) climates to assess metabolic responses to heat in heat-sensitive versus heat-tolerant embryos. We used untargeted LC\u2013MS to measure 33 metabolites and the major redox couples (NADH\/NAD\n                  <jats:sup>+<\/jats:sup>\n                  , NADPH\/NADP\n                  <jats:sup>+<\/jats:sup>\n                  , and GSH\/GSSG) at 25\u00b0C and after a 32\u00b0C heat shock. In all embryos, heat shock induced shared shifts in metabolic profiles, with increases in nucleotide monophosphates (\n                  <jats:italic>e.g.<\/jats:italic>\n                  , AMP, CMP, and GMP) and amino acids (\n                  <jats:italic>e.g.<\/jats:italic>\n                  , alanine, glutamic acid, serine). In contrast, redox metabolites diverged by region: heat-sensitive temperate embryos shifted toward a more oxidized state (46.6% decrease in NADH\/NAD\n                  <jats:sup>+<\/jats:sup>\n                  ratio and 4-fold increase in oxidized glutathione), while heat-tolerant tropical embryos maintained glutathione balance and increased the NADH\/NAD\n                  <jats:sup>+<\/jats:sup>\n                  ratio by 52.9%, indicating a more reduced state. These patterns are consistent with higher NADH oxidation and greater oxidative stress (inferred from oxidized glutathione) in the temperate embryos, versus better maintenance of redox balance in tropical embryos. Together, our results suggest that maintaining redox balance is a key determinant of acute heat tolerance, and healthy development overall, during early embryogenesis.\n                <\/jats:p>","DOI":"10.64898\/2026.06.30.733001","type":"posted-content","created":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T02:05:12Z","timestamp":1783130712000},"source":"Crossref","is-referenced-by-count":0,"title":["Heat stress drives opposing redox shifts in temperate versus tropical\n                  <i>Drosophila melanogaster<\/i>\n                  embryos"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5297-3777","authenticated-orcid":false,"given":"Thomas S.","family":"O\u2019Leary","sequence":"first","affiliation":[{"name":"Department of Biology, University of Vermont, Burlington, VT, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4694-5897","authenticated-orcid":false,"given":"Brent L.","family":"Lockwood","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Vermont, Burlington, VT, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026070709000658000_2026.06.30.733001v1.1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tips.2006.10.005"},{"key":"2026070709000658000_2026.06.30.733001v1.2","doi-asserted-by":"crossref","unstructured":"Arrhenius, S. (1889). \u00dcber die Dissociationsw\u00e4rme und den Einfluss der Temperatur auf den Dissociationsgrad der Elektrolyte. Zeitschrift f\u00fcr Physikalische Chemie 4U, 96\u2013116.","DOI":"10.1515\/zpch-1889-0408"},{"key":"2026070709000658000_2026.06.30.733001v1.3","doi-asserted-by":"publisher","DOI":"10.1016\/j.cbpb.2015.10.001"},{"key":"2026070709000658000_2026.06.30.733001v1.4","doi-asserted-by":"publisher","DOI":"10.3109\/02656736.2014.971446"},{"key":"2026070709000658000_2026.06.30.733001v1.5","doi-asserted-by":"publisher","DOI":"10.1016\/j.exger.2010.01.003"},{"key":"2026070709000658000_2026.06.30.733001v1.6","doi-asserted-by":"publisher","DOI":"10.1152\/nips.01514.2003"},{"key":"2026070709000658000_2026.06.30.733001v1.7","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-017-05679-1"},{"key":"2026070709000658000_2026.06.30.733001v1.8","doi-asserted-by":"crossref","unstructured":"Chung, D. J. and Schulte, P. M . (2020). Mitochondria and the thermal limits of ectotherms. J. Exp. Biol. 223,.","DOI":"10.1242\/jeb.227801"},{"key":"2026070709000658000_2026.06.30.733001v1.9","doi-asserted-by":"crossref","first-page":"886","DOI":"10.1111\/1365-2435.12264","article-title":"Thermal adaptation of cellular membranes in natural populations of Drosophila melanogaster","volume":"28","year":"2014","journal-title":"Funct. Ecol"},{"key":"2026070709000658000_2026.06.30.733001v1.10","doi-asserted-by":"publisher","DOI":"10.1242\/dev.02744"},{"key":"2026070709000658000_2026.06.30.733001v1.11","doi-asserted-by":"crossref","first-page":"bio061815","DOI":"10.1242\/bio.061815","article-title":"GSK3 coordinately regulates mitochondrial activity and nucleotide metabolism in quiescent oocytes","volume":"14","year":"2025","journal-title":"Biol. Open"},{"key":"2026070709000658000_2026.06.30.733001v1.12","doi-asserted-by":"publisher","DOI":"10.1038\/nrmicro.2017.26"},{"key":"2026070709000658000_2026.06.30.733001v1.13","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0228104"},{"key":"2026070709000658000_2026.06.30.733001v1.14","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.physiol.61.1.243"},{"key":"2026070709000658000_2026.06.30.733001v1.15","first-page":"1197","article-title":"Glutathione Depletion Disrupts Redox Homeostasis in an Anoxia-Tolerant Invertebrate","volume":"12","year":"2023","journal-title":"Antioxid. Redox Signal"},{"key":"2026070709000658000_2026.06.30.733001v1.16","doi-asserted-by":"publisher","DOI":"10.1002\/joc.5086"},{"key":"2026070709000658000_2026.06.30.733001v1.17","doi-asserted-by":"publisher","DOI":"10.1016\/j.mam.2008.08.006"},{"key":"2026070709000658000_2026.06.30.733001v1.18","doi-asserted-by":"publisher","DOI":"10.3109\/10409238.2013.764840"},{"key":"2026070709000658000_2026.06.30.733001v1.19","doi-asserted-by":"crossref","first-page":"1961","DOI":"10.1007\/s11357-022-00555-x","article-title":"Mitochondrial ROS signalling requires uninterrupted electron flow and is lost during ageing in flies","volume":"44","year":"2022","journal-title":"GeroScience"},{"key":"2026070709000658000_2026.06.30.733001v1.20","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbrc.2022.08.098"},{"key":"2026070709000658000_2026.06.30.733001v1.21","doi-asserted-by":"publisher","DOI":"10.1016\/j.celrep.2017.12.042"},{"key":"2026070709000658000_2026.06.30.733001v1.22","doi-asserted-by":"crossref","unstructured":"Han, X. , Sun, B. , Zhang, Q. , Teng, L. , Zhang, F. and Liu, Z . (2023). Metabolic regulation reduces the oxidative damage of arid lizards in response to moderate heat events. Integr. Zool.","DOI":"10.1111\/1749-4877.12784"},{"key":"2026070709000658000_2026.06.30.733001v1.23","doi-asserted-by":"crossref","unstructured":"Hasanuzzaman, M. , Bhuyan, M. H. M. B. , Zulfiqar, F. , Raza, A. , Mohsin, S. M. , Mahmud, J. A. , Fujita, M. and Fotopoulos, V . (2020). Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator. Antioxidants (Basel ) 9,.","DOI":"10.3390\/antiox9080681"},{"key":"2026070709000658000_2026.06.30.733001v1.24","doi-asserted-by":"publisher","DOI":"10.1016\/0169-5347(89)90211-5"},{"key":"2026070709000658000_2026.06.30.733001v1.25","doi-asserted-by":"publisher","DOI":"10.1016\/j.cmet.2011.08.012"},{"key":"2026070709000658000_2026.06.30.733001v1.26","first-page":"956","article-title":"Effects of Thermal Stress on Lipid Peroxidation and Antioxidant Enzyme Activities of Oriental Fruit Fly","volume":"94","year":"2011","journal-title":"Bactrocera dorsalis (Diptera: Tephritidae). flen"},{"key":"2026070709000658000_2026.06.30.733001v1.27","doi-asserted-by":"publisher","DOI":"10.1007\/s00227-016-2828-8"},{"key":"2026070709000658000_2026.06.30.733001v1.28","doi-asserted-by":"crossref","unstructured":"J\u00f8rgensen, L. B. , Overgaard, J. , Hunter-Manseau, F. and Pichaud, N . (2021). Dramatic changes in mitochondrial substrate use at critically high temperatures: a comparative study using Drosophila. J. Exp. Biol. 224,.","DOI":"10.1242\/jeb.240960"},{"key":"2026070709000658000_2026.06.30.733001v1.29","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2011.09.030"},{"key":"2026070709000658000_2026.06.30.733001v1.30","doi-asserted-by":"publisher","DOI":"10.1038\/srep33667"},{"key":"2026070709000658000_2026.06.30.733001v1.31","doi-asserted-by":"crossref","first-page":"7162","DOI":"10.3390\/molecules26237162","article-title":"Modified Arrhenius equation in materials science, chemistry and biology","volume":"26","year":"2021","journal-title":"Molecules"},{"key":"2026070709000658000_2026.06.30.733001v1.32","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.96.10.5452"},{"key":"2026070709000658000_2026.06.30.733001v1.33","doi-asserted-by":"publisher","DOI":"10.1046\/j.0022-3042.2002.00744.x"},{"key":"2026070709000658000_2026.06.30.733001v1.34","doi-asserted-by":"publisher","DOI":"10.1111\/jeb.13234"},{"key":"2026070709000658000_2026.06.30.733001v1.35","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2013.07.036"},{"key":"2026070709000658000_2026.06.30.733001v1.36","doi-asserted-by":"publisher","DOI":"10.1038\/srep28999"},{"key":"2026070709000658000_2026.06.30.733001v1.37","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmb.2006.10.033"},{"key":"2026070709000658000_2026.06.30.733001v1.38","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.00867.2005"},{"key":"2026070709000658000_2026.06.30.733001v1.39","first-page":", Unit7.2","article-title":"Measurement of glutathione reductase activity","volume":"7","year":"2001","journal-title":"Curr. Protoc. Toxicol. Chapter"},{"key":"2026070709000658000_2026.06.30.733001v1.40","doi-asserted-by":"crossref","first-page":"641","DOI":"10.1007\/s00775-024-02076-8","article-title":"Electron transfer in biological systems","volume":"29","year":"2024","journal-title":"J. Biol. Inorg. Chem"},{"key":"2026070709000658000_2026.06.30.733001v1.41","first-page":"20240973","article-title":"Heat tolerance, oxidative stress response tuning and robust gene activation in early-stage Drosophila melanogaster embryos","volume":"291","year":"2024","journal-title":"Proc. Biol. Sci"},{"key":"2026070709000658000_2026.06.30.733001v1.42","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbabio.2005.08.003"},{"key":"2026070709000658000_2026.06.30.733001v1.43","doi-asserted-by":"publisher","DOI":"10.1016\/S0891-5849(03)00464-7"},{"key":"2026070709000658000_2026.06.30.733001v1.44","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbrc.2007.04.106"},{"key":"2026070709000658000_2026.06.30.733001v1.45","doi-asserted-by":"publisher","DOI":"10.1042\/BJ20081386"},{"key":"2026070709000658000_2026.06.30.733001v1.46","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1038\/s42255-022-00591-z","article-title":"Guidelines for measuring reactive oxygen species and oxidative damage in cells and in vivo","volume":"4","year":"2022","journal-title":"Nat Metab"},{"key":"2026070709000658000_2026.06.30.733001v1.47","doi-asserted-by":"crossref","first-page":"e2518358123","DOI":"10.1073\/pnas.2518358123","article-title":"Early life-stage thermal resilience is determined by climate-linked regulatory variation","volume":"123","year":"2026","journal-title":"Proc. Natl. Acad. Sci. U. S. A"},{"key":"2026070709000658000_2026.06.30.733001v1.48","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1807918115"},{"key":"2026070709000658000_2026.06.30.733001v1.49","unstructured":"R Core Team (2025). R: A Language and Environment for Statistical Computing."},{"key":"2026070709000658000_2026.06.30.733001v1.50","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2010.09.014"},{"key":"2026070709000658000_2026.06.30.733001v1.51","doi-asserted-by":"crossref","unstructured":"Ritz, C. , Baty, F. , Streibig, J. C. and Gerhard, D . (2015). Dose-Response Analysis Using R. PLOS ONE 10,.","DOI":"10.1371\/journal.pone.0146021"},{"key":"2026070709000658000_2026.06.30.733001v1.52","doi-asserted-by":"crossref","first-page":"coae031","DOI":"10.1093\/conphys\/coae031","article-title":"Heat exposure limits pentose phosphate pathway activity in bumblebees","volume":"12","year":"2024","journal-title":"Conserv. Physiol"},{"key":"2026070709000658000_2026.06.30.733001v1.53","doi-asserted-by":"crossref","first-page":"873","DOI":"10.1007\/s10522-016-9657-5","article-title":"Mild heat treatments induce long-term changes in metabolites associated with energy metabolism in Drosophila melanogaster","volume":"17","year":"2016","journal-title":"Biogerontology"},{"key":"2026070709000658000_2026.06.30.733001v1.54","doi-asserted-by":"publisher","DOI":"10.1016\/S0891-5849(01)00480-4"},{"key":"2026070709000658000_2026.06.30.733001v1.55","doi-asserted-by":"crossref","first-page":"934","DOI":"10.1111\/1365-2435.12782","article-title":"Linear reaction norms of thermal limits in Drosophila : predictable plasticity in cold but not in heat tolerance","volume":"31","year":"2017","journal-title":"Funct. Ecol"},{"key":"2026070709000658000_2026.06.30.733001v1.56","doi-asserted-by":"publisher","DOI":"10.1126\/science.1850548"},{"key":"2026070709000658000_2026.06.30.733001v1.57","first-page":"1","article-title":"Reactive oxygen species, oxidative damage, and antioxidative defense mechanism in plants under stressful conditions","volume":"2012","year":"2012","journal-title":"J. Bot"},{"key":"2026070709000658000_2026.06.30.733001v1.58","doi-asserted-by":"publisher","DOI":"10.1098\/rstb.1985.0168"},{"key":"2026070709000658000_2026.06.30.733001v1.59","doi-asserted-by":"publisher","DOI":"10.1038\/s41580&ndash;020&ndash;0230&ndash;3"},{"key":"2026070709000658000_2026.06.30.733001v1.60","doi-asserted-by":"publisher","DOI":"10.1046\/j.1432-1327.2001.02179.x"},{"key":"2026070709000658000_2026.06.30.733001v1.61","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2012.11.022"},{"key":"2026070709000658000_2026.06.30.733001v1.62","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.ph.57.030195.000355"},{"key":"2026070709000658000_2026.06.30.733001v1.63","unstructured":"Somero, G. N. , Lockwood, B. L. and Tomanek, L . (2017). Biochemical Adaptation: Response to Environmental Challenges, from Life\u2019s Origins to the Anthropocene. Sunderland, MA: Sinauer Associates, Inc."},{"key":"2026070709000658000_2026.06.30.733001v1.64","doi-asserted-by":"publisher","DOI":"10.1111\/brv.12140"},{"key":"2026070709000658000_2026.06.30.733001v1.65","first-page":"20","article-title":"Management of heat stress in Drosophila melanogaster with Abhrak bhasma and ascorbic acid as antioxidant supplements","volume":"6","year":"2018","journal-title":"J. Appl. Biol. Biotechnol"},{"key":"2026070709000658000_2026.06.30.733001v1.66","doi-asserted-by":"crossref","first-page":"e23362","DOI":"10.1002\/dvg.23362","article-title":"Reactive oxygen species signaling in primordial germ cell development in Drosophila embryos","volume":"58","year":"2020","journal-title":"Genesis"},{"key":"2026070709000658000_2026.06.30.733001v1.67","doi-asserted-by":"publisher","DOI":"10.1262\/jrd.11-138N"},{"issue":"4","key":"2026070709000658000_2026.06.30.733001v1.68","first-page":"839","article-title":"Coordinated metabolic transitions during Drosophila embryogenesis and the onset of aerobic glycolysis","volume":"3","year":"2014","journal-title":"G"},{"key":"2026070709000658000_2026.06.30.733001v1.69","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2013.06.011"},{"key":"2026070709000658000_2026.06.30.733001v1.70","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M111.252502"},{"key":"2026070709000658000_2026.06.30.733001v1.71","doi-asserted-by":"publisher","DOI":"10.1016\/S0076-6879(05)01013-X"},{"key":"2026070709000658000_2026.06.30.733001v1.72","doi-asserted-by":"publisher","DOI":"10.3389\/fnmol.2011.00012"},{"key":"2026070709000658000_2026.06.30.733001v1.73","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2164-7-142"},{"key":"2026070709000658000_2026.06.30.733001v1.74","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.2023.2700"},{"key":"2026070709000658000_2026.06.30.733001v1.75","doi-asserted-by":"crossref","first-page":"1447","DOI":"10.3390\/molecules28031447","article-title":"Glutathione-related enzymes and proteins: A review","volume":"28","year":"2023","journal-title":"Molecules"},{"key":"2026070709000658000_2026.06.30.733001v1.76","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbabio.2008.04.014"},{"key":"2026070709000658000_2026.06.30.733001v1.77","doi-asserted-by":"publisher","DOI":"10.1038\/nprot.2009.197"},{"key":"2026070709000658000_2026.06.30.733001v1.78","doi-asserted-by":"crossref","first-page":"1686","DOI":"10.21105\/joss.01686","article-title":"Welcome to the tidyverse","volume":"4","year":"2019","journal-title":"Journal of Open Source Software"},{"key":"2026070709000658000_2026.06.30.733001v1.79","doi-asserted-by":"publisher","DOI":"10.1093\/nar\/gkab1062"},{"key":"2026070709000658000_2026.06.30.733001v1.80","doi-asserted-by":"publisher","DOI":"10.2174\/2213235X11301010092"},{"key":"2026070709000658000_2026.06.30.733001v1.81","doi-asserted-by":"publisher","DOI":"10.1089\/ars.2017.7216"},{"key":"2026070709000658000_2026.06.30.733001v1.82","doi-asserted-by":"crossref","first-page":"4541","DOI":"10.3390\/ijms26104541","article-title":"Changes in metabolomics profiles of Propylea japonica in response to acute heat stress","volume":"26","year":"2025","journal-title":"Int. J. Mol. Sci"},{"key":"2026070709000658000_2026.06.30.733001v1.83","doi-asserted-by":"publisher","DOI":"10.1089\/ars.2007.1672"},{"key":"2026070709000658000_2026.06.30.733001v1.84","doi-asserted-by":"crossref","unstructured":"Zhang, Y. and Wong, H. S . (2021). Are mitochondria the main contributor of reactive oxygen species in cells? J. Exp. Biol. 224,.","DOI":"10.1242\/jeb.221606"},{"key":"2026070709000658000_2026.06.30.733001v1.85","doi-asserted-by":"publisher","DOI":"10.3892\/ijmm.2019.4188"},{"key":"2026070709000658000_2026.06.30.733001v1.86","doi-asserted-by":"crossref","first-page":"13381","DOI":"10.1038\/s41598-017-13560-4","article-title":"Effects of short-term heat shock and physiological responses to heat stress in two Bradysia adults, Bradysia odoriphaga and Bradysia difformis","volume":"7","year":"2017","journal-title":"Sci. Rep"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.06.30.733001","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T16:00:40Z","timestamp":1783440040000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.06.30.733001"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,3]]},"references-count":86,"URL":"https:\/\/doi.org\/10.64898\/2026.06.30.733001","relation":{},"subject":[],"published":{"date-parts":[[2026,7,3]]},"subtype":"preprint"}}