title: Mercury species, selenium, metallothioneins and glutathione in two dolphins from the southeastern Brazilian coast: Mercury detoxification and physiological differences in diving capacity.
abstract: In the present study, the concentration of trace elements, total mercury (Hg) and selenium (Se) and mercury forms (MeHg, Hginorg and HgSe) in the vulnerable coastal dolphins Pontoporia blainvillei and Sotalia guianensis were appraised and compared, using metallothioneins (MT) and glutathione (GSH) as biomarkers for trace element exposure. The trace element concentrations varied between muscle and liver tissues, with liver of all dolphin specimens showing higher Hg and Se concentrations than those found in muscle. Hg, MeHg and Hginorg molar concentrations showed a clear increase with Se molar concentrations in the liver of both dolphins, and Se concentrations were higher than those of Hg on a molar basis. Se plays a relevant role in the detoxification of MeHg in the hepatic tissue of both dolphins, forming Hg-Se amorphous crystals in liver. In contrast, MT were involved in the detoxification process of Hginorg in liver. GSH levels in P. blainvillei and S. guianensis muscle tissue suggest that these dolphins have different diving capacities. Muscle Hg concentrations were associated to this tripeptide, which protects dolphin cells against Hg stress.
authors.affiliation: Universidade Estadual do Norte Fluminense, Laboratório de Ciências Ambientais, 28013-602 Campos dos Goytacazes, RJ, Brazil; Universidade Federal do Rio de Janeiro, IBCCF, Laboratório de Radioisótopos, 21941-902 Rio de Janeiro, RJ, Brazil. Electronic address: helena.kehrig@pq.cnpq.br.
authors.forename: Helena A
authors.initials: HA
authors.lastname: Kehrig
authors.affiliation: Universidade Federal do Estado do Rio de Janeiro, Programa de Pós-Graduação em Ciências Biológicas, Biodiversidade Neotropical, 22290-240 Rio de Janeiro, RJ, Brazil. Electronic address: rachel.hauser.davis@gmail.com.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Hauser-Davis
authors.affiliation: Universidade Federal do Rio de Janeiro, IBCCF, Laboratório de Radioisótopos, 21941-902 Rio de Janeiro, RJ, Brazil. Electronic address: terciaguedes@gmail.com.
authors.forename: Tercia G
authors.initials: TG
authors.lastname: Seixas
authors.affiliation: PUC - Rio, Dep. de Química, 22453-900 Rio de Janeiro, RJ, Brazil. Electronic address: abiapinheiro@gmail.com.
authors.forename: Ana Beatriz
authors.initials: AB
authors.lastname: Pinheiro
authors.affiliation: Universidade Estadual do Norte Fluminense, Laboratório de Ciências Ambientais, 28013-602 Campos dos Goytacazes, RJ, Brazil. Electronic address: anadibeneditto@gmail.com.
authors.forename: Ana Paula M
authors.initials: APM
authors.lastname: Di Beneditto
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001938:Brazil; D004242:Diving / Q000502:physiology*; D004289:Dolphins / Q000378:metabolism*; D005260:Female; D005978:Glutathione / Q000378:metabolism*; D008658:Inactivation, Metabolic; D008099:Liver / Q000378:metabolism; D008297:Male; D008628:Mercury / Q000032:analysis* / Q000493:pharmacokinetics; D017669:Mercury Compounds / Q000032:analysis / Q000493:pharmacokinetics; D008668:Metallothionein / Q000378:metabolism*; D008767:Methylmercury Compounds / Q000032:analysis / Q000493:pharmacokinetics; D009132:Muscles / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D012643:Selenium / Q000032:analysis* / Q000493:pharmacokinetics; D018036:Selenium Compounds / Q000032:analysis / Q000493:pharmacokinetics; D014131:Trace Elements / Q000032:analysis / Q000493:pharmacokinetics; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics
chemical_list: D015415:Biomarkers; D017669:Mercury Compounds; D008767:Methylmercury Compounds; D018036:Selenium Compounds; D014131:Trace Elements; D014874:Water Pollutants, Chemical; C032901:mercury-selenium complex; D008668:Metallothionein; D008628:Mercury; D005978:Glutathione; D012643:Selenium
keywords: Biomarkers; Detoxification; Hg-Se granules; Marine mammals; Oxidative stress; South Atlantic Ocean