{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,8]],"date-time":"2025-11-08T12:20:03Z","timestamp":1762604403460,"version":"3.40.5"},"reference-count":32,"publisher":"Public Library of Science (PLoS)","issue":"8","license":[{"start":{"date-parts":[[2023,8,8]],"date-time":"2023-08-08T00:00:00Z","timestamp":1691452800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"East Tennessee State University Honors College"},{"name":"Impetus Foundation"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Gluconeogenesis (GNG) is the process of regenerating glucose and NAD+ that allows for continued ATP synthesis by glycolysis during fasting or in hypoxia. Recent data from <jats:italic>C<\/jats:italic>. <jats:italic>elegans<\/jats:italic> and crustaceans challenged with hypoxia show differential and tissue-specific expression of GNG-specific genes. Here we report differential expression of several GNG-specific genes in the head and body of a model organism, <jats:italic>Daphnia magna<\/jats:italic>, a planktonic crustacean, in normoxic and acute hypoxic conditions. We predict that GNG-specific transcripts will be enriched in the body, where most of the fat tissue is located, rather than in the head, where the tissues critical for survival in hypoxia, the central nervous system and locomotory muscles, are located. We measured the relative expression of GNG-specific transcripts in each body part by qRT-PCR and normalized them by either the expression of a reference gene or the rate-limiting glycolysis enzyme pyruvate kinase (PK). Our data show that of the three GNG-specific transcripts tested, pyruvate carboxylase (PC) showed no differential expression in either the head or body. Phosphoenolpyruvate carboxykinase (PEPCK-C), on the other hand, is upregulated in hypoxia in both body parts. Fructose-1,6-bisphosphatase (FBP) is upregulated in the body relative to the head and upregulated in hypoxia relative to normoxia, with a stronger body effect in hypoxia when normalized by PK expression. These results support our hypothesis that <jats:italic>Daphnia<\/jats:italic> can survive hypoxic conditions by implementing the Cori cycle, where body tissues supply glucose and NAD+ to the brain and muscles, enabling them to continuously generate ATP by glycolysis.<\/jats:p>","DOI":"10.1371\/journal.pone.0284679","type":"journal-article","created":{"date-parts":[[2023,8,8]],"date-time":"2023-08-08T17:27:50Z","timestamp":1691515670000},"page":"e0284679","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":4,"title":["Differential expression of gluconeogenesis-related transcripts in a freshwater zooplankton model organism suggests a role of the Cori cycle in hypoxia tolerance"],"prefix":"10.1371","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6796-1899","authenticated-orcid":true,"given":"Morad C.","family":"Malek","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jyoti R.","family":"Behera","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1270-2299","authenticated-orcid":true,"given":"Aruna","family":"Kilaru","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7680-6025","authenticated-orcid":true,"given":"Lev Y.","family":"Yampolsky","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2023,8,8]]},"reference":[{"key":"pone.0284679.ref001","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/S0021-9258(18)83822-4","article-title":"Glycogen formation in the liver from d- and l-lactic acid","volume":"81","author":"C.F. Cori","year":"1929","journal-title":"J Biol Chem"},{"key":"pone.0284679.ref002","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1016\/S0021-9258(18)81288-1","article-title":"Quantitative estimation of the Cori cycle in the human","volume":"238","author":"G. A. Reichard","year":"1963","journal-title":"J. Biol. Chem"},{"issue":"12","key":"pone.0284679.ref003","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1056\/NEJM197003192821209","article-title":"Starvation in Man.","volume":"282","author":"G. F. Cahill","year":"1970","journal-title":"New England Journal of Medicine"},{"key":"pone.0284679.ref004","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1016\/0014-5793(76)80532-7","article-title":"Effect of fasting on the Cori cycle in rats","volume":"66","author":"A. Freminet","year":"1976","journal-title":"FEBS Lett"},{"key":"pone.0284679.ref005","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1016\/B978-0-12-152818-8.50028-1","article-title":"The glucose-lactic acid cycle and gluconeogenesis","volume":"18","author":"C.F. Cori","year":"1981","journal-title":"Current Topics in Cellular Regulation"},{"key":"pone.0284679.ref006","first-page":"543","volume-title":"Lehninger Principles of Biochemistry (Fourth ed.).","author":"D.L. Nelson","year":"2005"},{"issue":"Pt 5","key":"pone.0284679.ref007","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1242\/jeb.01476","article-title":"Glucose production and substrate cycle activity in a fasting adapted animal, the northern elephant seal","volume":"208","author":"C.D. Champagne","year":"2005","journal-title":"J Exp Biol."},{"issue":"10","key":"pone.0284679.ref008","doi-asserted-by":"crossref","first-page":"1548","DOI":"10.3390\/biom11101548","article-title":"New insights to regulation of fructose-1,6-bisphosphatase during anoxia in red-eared slider, Trachemys scripta elegans","volume":"11","author":"A. Gupta","year":"2021","journal-title":"Biomolecules"},{"issue":"13","key":"pone.0284679.ref009","doi-asserted-by":"crossref","first-page":"2795","DOI":"10.1016\/j.febslet.2005.03.097","article-title":"Molecular mechanism of hypoxia-mediated hepatic gluconeogenesis by transcriptional regulation","volume":"579","author":"J.H. Choi","year":"2005","journal-title":"FEBS Lett."},{"issue":"7","key":"pone.0284679.ref010","doi-asserted-by":"crossref","first-page":"e04334","DOI":"10.1016\/j.heliyon.2020.e04334","article-title":"Changes in expression of genes related to glucose metabolism in liver and skeletal muscle of rats exposed to acute hypoxia","volume":"6","author":"Y. Hara","year":"2020","journal-title":"Heliyon"},{"issue":"172","key":"pone.0284679.ref011","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.biochi.2020.02.002","article-title":"Hypoxia increases the rate of renal gluconeogenesis via hypoxia-inducible factor-1-dependent activation of phosphoenolpyruvate carboxykinase expression","volume":"171","author":"A. Owczarek","year":"2020","journal-title":"Biochimie"},{"key":"pone.0284679.ref012","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1242\/jeb.037523","article-title":"Oxygen\u2010 and capacity limitation of thermal tolerance: A matrix for integrating climate related stressor effects in marine ecosystem","volume":"213","author":"P\u00f6rtner, H. O","year":"2010","journal-title":"Journal of Experimental Biology"},{"key":"pone.0284679.ref013","article-title":"Limits of the thermal tolerance of two lentic crustaceans: The role of lactate dehydrogenase","author":"B. Zeis","year":"2023","journal-title":"J Exp Zool A Ecol Integr Physiol. In press"},{"key":"pone.0284679.ref014","doi-asserted-by":"crossref","first-page":"111212","DOI":"10.1016\/j.cbpa.2022.111212","article-title":"The anaplerotic pyruvate carboxylase from white shrimp Litopenaeus vannamei: Gene structure, molecular characterization, protein modelling and expression during hypoxia","volume":"269","author":"O.N. 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Krycer","year":"2020","journal-title":"J Biol Chem"}],"container-title":["PLOS ONE"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0284679","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,8,8]],"date-time":"2023-08-08T17:28:18Z","timestamp":1691515698000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0284679"}},"subtitle":[],"editor":[{"given":"Bashir Sajo","family":"Mienda","sequence":"first","affiliation":[],"role":[{"role":"editor","vocabulary":"crossref"}]}],"short-title":[],"issued":{"date-parts":[[2023,8,8]]},"references-count":32,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2023,8,8]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0284679","relation":{},"ISSN":["1932-6203"],"issn-type":[{"type":"electronic","value":"1932-6203"}],"subject":[],"published":{"date-parts":[[2023,8,8]]}}}