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Advisor(s)
Abstract(s)
Algal cells can be exposed to toxicants for a short-term due to accidental discharges or,
more commonly, for a long-term. The present work aimed to assess the ability of Cd, Cr,
Cu, and Zn to induce accumulation of reactive oxygen species (ROS) in the alga
Pseudokirchneriella subcapitata after a short (6 h) or a long (72 h) exposure time. The
relationship between the ROS induction and the content of reduced glutathione (GSH)
was also examined. For this purpose, three nominal concentrations of each metal were
used corresponding approximately to 72 h-EC10 and 72 h-EC50 values and a high
concentration (>72 h-EC90 values). Intracellular ROS accumulation and GSH content
were evaluated using a fluorescent-based approach. A long-term (chronic) exposure of
algal cells to Cd, Cu, and Zn, at the highest concentrations tested, induced an increase
of intracellular ROS and GSH content. The increase of GSH content might be a form of
algal cells to redress the imbalance caused by the oxidative stress. However, the
increase of GSH was not enough to protect the algal cells against the long-term
exposure to oxidative stress. The exposure of algal cells to low or intermediate metals
concentrations induced a modification of GSH content; however, no increase of ROS
production was detected, which indicates that the toxic symptoms exhibited by algal
cells, under these conditions, cannot be attributed to intracellular ROS accumulation.
Description
Keywords
20,70-Dichlorodihydrofluorescein diacetate (H2DCFDA) Monochlorobimane (mBCl) Reactive oxygen species (ROS) Reduced glutathione (GSH) Toxicity
Citation
Publisher
Wiley-VCH Verlag