Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/50889
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dc.contributor.authorDortch, Quayen_US
dc.contributor.authorAhmed, S. I.en_US
dc.contributor.authorPackard, T. T.en_US
dc.date.accessioned2018-11-24T19:40:24Z-
dc.date.available2018-11-24T19:40:24Z-
dc.date.issued1979en_US
dc.identifier.issn0142-7873en_US
dc.identifier.urihttp://hdl.handle.net/10553/50889-
dc.description.abstractNitrate reductase (NADH-NR) and glutamate dehydrogenase (NADPH-GDH) activities were measured in Skeletonema costatum (Grev.) Cleve in ammonium and nitrate limited continuous cultures before and after additions of nitrate and/or ammonium. Comparisons of enzymic activity with nitrogen uptake and assimilation rates, external and internal nitrate concentrations, and external ammonium concentrations were made in order to assess the roles of NR and GDH in nitrogen assimilation and to determine their suitability as measures of nitrogen assimilation rates. NR activity appeared to be induced by internal rather than external nitrate concentrations. Ammonium in the medium reduced NR activity under some environmental conditions, but not others. However, ammonium acted indirectly, perhaps by causing the accumulation of an internal pool of an intermediate of ammonium assimilation. NR activity was found to approximate nitrate assimilation rates during growth limited by the nitrate supply and undeT some conditions in the presence of high nitrate and ammonium concentrations in the medium. Under other environmental conditions, NR activity did not agree with nitrate assimilation rates; a second nitrate reducing mechanism may operate when these conditions prevail. GDH activities were consistently low, representing less than 5% of the ammonium uptake and assimilation rates. Consequently, it is proposed that ODH is not the primary ammonium assimilating enzyme under most environmental conditions and cannot be used as a measure of ammonium assimilation.en_US
dc.languageengen_US
dc.publisher0142-7873-
dc.relation.ispartofJournal of Plankton Researchen_US
dc.sourceJournal of Plankton Research [ISSN 0142-7873], v. 1, p. 169-186en_US
dc.subject251001 Oceanografía biológicaen_US
dc.subject2302 Bioquímicaen_US
dc.titleNitrate reductase and glutamate dehydrogenase activities in Skeletonema costatum as measures of nitrogen assimilation ratesen_US
dc.typeinfo:eu-repo/semantics/articleen_US
dc.typeArticleen_US
dc.identifier.doi10.1093/plankt/1.2.169en_US
dc.identifier.scopus0000528514-
dc.contributor.authorscopusid6701785246-
dc.contributor.authorscopusid8973803500-
dc.contributor.authorscopusid7004249480-
dc.description.lastpage186-
dc.description.firstpage169-
dc.relation.volume1-
dc.investigacionCienciasen_US
dc.type2Artículoen_US
dc.utils.revisionen_US
dc.identifier.ulpgces
dc.description.scieSCIE
item.fulltextSin texto completo-
item.grantfulltextnone-
crisitem.author.orcid0000-0002-5880-1199-
crisitem.author.fullNamePackard, Theodore Train-
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