Detoxification and elimination of nicotine by nectar-feeding birds

dc.contributor.authorLerch-Henning, Sara
dc.contributor.authorDu Rand, Esther Elizabeth
dc.contributor.authorNicolson, Sue W.
dc.contributor.emailezette.durand@up.ac.zaen_ZA
dc.date.accessioned2017-03-09T09:39:49Z
dc.date.issued2017-05
dc.description.abstractMany dilute nectars consumed by bird pollinators contain secondary metabolites, potentially toxic chemicals produced by plants as defences against herbivores. Consequently, nectar-feeding birds are challenged not only by frequent water excess, but also by the toxin content of their diet. High water turnover, however, could be advantageous to nectar consumers by enabling them to excrete secondary metabolites or their transformation products more easily. We investigated how the alkaloid nicotine, naturally present in nectar of Nicotiana species, influences osmoregulation in white-bellied sunbirds Cinnyris talatala and Cape white-eyes Zosterops virens.We also examined the metabolic fate of nicotine in these two species to shed more light on the post-ingestive mechanisms that allow nectar-feeding birds to tolerate nectar nicotine. A high concentration of nicotine (50 μM) decreased cloacal fluid output and increased its osmolality in both species, due to reduced food intake that led to dehydration. White-eyes excreted a higher proportion of the ingested nicotine-containing diet than sunbirds. However, sugar concentration did not affect nicotine detoxification and elimination. Both species metabolised nicotine, excreting very little unchanged nicotine. Cape white-eyes mainly metabolised nicotine through the cotinine metabolic pathway, with norcotinine being the most abundant metabolite in the excreta, while white-bellied sunbirds excreted mainly nornicotine. Both species also utilized phase II conjugation reactions to detoxify nicotine, with Cape white-eyes depending more on the mercapturic acid pathway to detoxify nicotine than white-bellied sunbirds. We found that sunbirds and white-eyes, despite having a similar nicotine tolerance, responded differently and used different nicotine-derived metabolites to excrete nicotine.en_ZA
dc.description.departmentBiochemistryen_ZA
dc.description.departmentZoology and Entomologyen_ZA
dc.description.embargo2018-05-28
dc.description.librarianhb2017en_ZA
dc.description.urihttp://link.springer.com/journal/360en_ZA
dc.identifier.citationLerch-Henning, S., Du Rand, E.E. & Nicolson, S.W. Detoxification and elimination of nicotine by nectar-feeding birds. Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology (2017) 187: 591-602. https://doi.org/10.1007/s00360-016-1055-4.en_ZA
dc.identifier.issn0174-1578 (print)
dc.identifier.issn1432-136X (online)
dc.identifier.other10.1007/s00360-016-1055-4
dc.identifier.urihttp://hdl.handle.net/2263/59346
dc.language.isoenen_ZA
dc.publisherSpringeren_ZA
dc.rights© Springer-Verlag Berlin Heidelberg 2017. The original publication is available at : http://link.springer.comjournal/360.en_ZA
dc.subjectDetoxificationen_ZA
dc.subjectExcretionen_ZA
dc.subjectNectaren_ZA
dc.subjectNectar-feeding birdsen_ZA
dc.subjectNicotineen_ZA
dc.subjectOmoregulationen_ZA
dc.titleDetoxification and elimination of nicotine by nectar-feeding birdsen_ZA
dc.typePostprint Articleen_ZA

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