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Authors
Advisor(s)
Abstract(s)
The yeast Saccharomyces cerevisiae is a useful
model organism for studying lead (Pb) toxicity. Yeast cells
of a laboratory S. cerevisiae strain (WT strain) were incubated
with Pb concentrations up to 1,000 μmol/l for 3 h. Cells
exposed to Pb lost proliferation capacity without damage to
the cell membrane, and they accumulated intracellular superoxide
anion (O2
.−) and hydrogen peroxide (H2O2). The involvement
of the mitochondrial electron transport chain
(ETC) in the generation of reactive oxygen species (ROS)
induced by Pb was evaluated. For this purpose, an isogenic
derivative ρ0 strain, lacking mitochondrial DNA, was used.
The ρ0 strain, without respiratory competence, displayed a
lower intracellular ROS accumulation and a higher resistance
to Pb compared to the WT strain. The kinetic study of ROS
generation in yeast cells exposed to Pb showed that the production
of O2
.− precedes the accumulation of H2O2, which is
compatible with the leakage of electrons from the mitochondrial
ETC. Yeast cells exposed to Pb displayed mutations at
the mitochondrial DNA level. This is most likely a consequence
of oxidative stress. In conclusion, mitochondria are an
important source of Pb-induced ROS and, simultaneously, one
of the targets of its toxicity.
Description
Keywords
Lead (Pb) toxicity Mitochondria Reactive oxygen species (ROS) Respiratory-deficient cells Viability Yeast
Pedagogical Context
Citation
Publisher
Springer Verlag