Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/5/2008
Publication Date: 10/18/2009
Citation: Schrader, K., Dayan, F.E. 2009. Antioxidant Enzyme Activities in the Cyanobacteria Planktothrix Agardhii, Planktothrix Perornata, Raphidiopsis Brookii, and the Green Alga Selenastrum Capricornutum In Handbook on Cyanobacteria. P.M. Gault and H.J. Marler, eds., Nova Science Publishers, Inc., Hauppauge, NY. PP. 474-483. Interpretive Summary: A type of blue-green alga that causes musty off-flavor in farm-raised channel catfish in Mississippi was studied and found to have deficiencies of certain enzyme activities that help protect it. Such deficiencies are believed to be the reason for the selective toxicity of a novel natural-based algicide. A green alga found in Mississippi catfish ponds was not deficient in certain enzyme activities when compared to the musty-odor producing blue-green alga.
Technical Abstract: Previous studies have demonstrated that compounds generating reactive oxygen species (ROS) are selectively toxic towards certain species of cyanobacteria (blue-green algae) when compared to green algae (e.g., Selenastrum capricornutum). The antioxidant enzyme activities of S. capricornutum and several species of cyanobacteria (Planktothrix agardhii, Planktothrix perornata, and Raphidiopsis brookii) previously isolated from catfish aquaculture ponds were measured to help determine the cause for the selective toxicity of ROS-generating compounds. Enzyme assays were performed to quantify the specific enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The cyanobacteria used in this study had much lower specific activities of superoxide dismutase, catalase, and ascorbate peroxidase compared to S. capricornutum. Glutathione peroxidase activity was not detected in the cyanobacteria or S. capricornutum. The deficiency of antioxidant enzyme activities in the cyanobacteria is at least one reason for the selective toxicity of ROS-generating compounds towards these microorganisms compared to other types of phytoplankton such as S. capricornutum.