Use este identificador para citar ou linkar para este item: https://repositorio.inpa.gov.br/handle/1/15225
Título: Dissolved organic carbon from the upper Rio Negro protects zebrafish (Danio rerio) against ionoregulatory disturbances caused by low pH exposure
Autor: Duarte, Rafael Mendonça
Smith, Donald Scott
Val, Adalberto Luis
Wood, Chris M.
Palavras-chave: Calcium
Carbon
Ion
Sodium
Animals
Chemistry
Growth, Development And Aging
Ph
Stress, Physiological
River
Zebrafish
Animal
Calcium
Carbon
Hydrogen-ion Concentration
Ions
Rivers
Sodium
Stress, Physiological
Zebrafish
Data do documento: 2016
Revista: Scientific Reports
É parte de: Volume 6
Abstract: The so-called â œ blackwatersâ of the Amazonian Rio Negro are rich in highly coloured dissolved organic carbon (DOC), but ion-poor and very acidic, conditions that would cause fatal ionoregulatory failure in most fish. However these blackwaters support 8% of the worldâ ™ s ichthyofauna. We tested the hypothesis that native DOC provides protection against ionoregulatory dysfunction in this extreme environment. DOCs were isolated by reverse-osmosis from two Rio Negro sites. Physico-chemical characterization clearly indicated a terrigenous origin, with a high proportion of hydroxyl and phenolic sites, high chemical reactivity to protons, and unusual proteinaceous fluorescence. When tested using zebrafish (a model organism), Rio Negro DOC provided almost perfect protection against ionoregulatory disturbances associated with acute exposure to pH 4.0 in ion-poor water. DOC reduced diffusive losses of Na + and Cl â', and promoted a remarkable stimulation of Na + uptake that otherwise would have been completely inhibited. Additionally, prior acclimation to DOC at neutral pH reduced rates of branchial Na + turnover, and provided similar protection against acid-induced ionoregulatory disturbances, even if the DOC was no longer present. These results reinforce the important roles that DOC molecules can play in the regulation of gill functions in freshwater fish, particularly in ion-poor, acidic blackwaters.
DOI: 10.1038/srep20377
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