Polar coastal seawaters are saturated by high oxygen concentrations, which impose very effective adaptive strategies to strive against a continuous environmental oxidative stress. We studied these strategies in Euplotes nobilii (Ciliophora: Spirotrichea), a ciliate species dwelling in Antarctic and Arctic coastal seawaters, in comparison with Euplotes raikovi, a sister species living in temperate seawaters. Cell samples of the two species were exposed to hydrogen peroxide (H2O2)-induced oxidative stress and analyzed for their survival rates and levels of expression of the genes encoding the enzyme methionine-sulfoxide reductase (Msr) A, which restores oxidized methionines (in their S form) of damaged proteins to the status of functional methionines. While 6 h of exposure to a 750-µM concentration of H2O2 did not affect E. nobilii viability, these conditions were lethal to E. raikovi. In correlation with this inter-specific difference in the cell survival to oxidative stress, the MsrA-coding genes of the two species showed different mechanisms of expression: constitutive in E. nobilii, elicited by induction in E. raikovi.

Polar and non-polar species of the protozoan ciliate Euplotes behave differently in response to environmental oxidative stress

DOBRI, NICOLETA;ALIMENTI, Claudio;VALLESI, Adriana
2014-01-01

Abstract

Polar coastal seawaters are saturated by high oxygen concentrations, which impose very effective adaptive strategies to strive against a continuous environmental oxidative stress. We studied these strategies in Euplotes nobilii (Ciliophora: Spirotrichea), a ciliate species dwelling in Antarctic and Arctic coastal seawaters, in comparison with Euplotes raikovi, a sister species living in temperate seawaters. Cell samples of the two species were exposed to hydrogen peroxide (H2O2)-induced oxidative stress and analyzed for their survival rates and levels of expression of the genes encoding the enzyme methionine-sulfoxide reductase (Msr) A, which restores oxidized methionines (in their S form) of damaged proteins to the status of functional methionines. While 6 h of exposure to a 750-µM concentration of H2O2 did not affect E. nobilii viability, these conditions were lethal to E. raikovi. In correlation with this inter-specific difference in the cell survival to oxidative stress, the MsrA-coding genes of the two species showed different mechanisms of expression: constitutive in E. nobilii, elicited by induction in E. raikovi.
2014
262
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11581/333991
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