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ANTIOXIDANT ENZYME RESPONSE AND REACTIVE OXYGEN SPECIES PRODUCTION IN MARINE RAPHIDOPHYTES 1
Author(s) -
Portune Kevin J.,
Craig Cary Stephen,
Warner Mark E.
Publication year - 2010
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2010.00906.x
Subject(s) - heterosigma akashiwo , catalase , superoxide dismutase , reactive oxygen species , biology , antioxidant , exponential growth , oxidative stress , biochemistry , radical , superoxide , hydrogen peroxide , enzyme , botany , nutrient , ecology , algal bloom , phytoplankton , mathematical analysis , mathematics
Raphidophytes (class Raphidophyceae) produce high levels of reactive oxygen species (ROS), yet little is known regarding cellular scavenging mechanisms needed for protection against these radicals. Enzymatic activities of the antioxidants superoxide dismutase (SOD) and catalase (CAT) were measured in conjunction with the production of superoxide (O 2 •− ) and hydrogen peroxide (H 2 O 2 ) in batch cultures of five different raphidophytes species during early exponential, late‐exponential, and stationary growth phases. The greatest concentrations of O 2 •− per cell were detected during exponential growth with reduced levels in stationary phases in raphidophytes Heterosigma akashiwo (Hada) Hada ex Y. Hara et Chihara, Chattonella marina (Subrahman.) Y. Hara et Chihara, and Chattonella antiqua (Hada) Ono (strain 18). Decreasing trends from exponential to stationary phases for SOD activity and H 2 O 2 per cell were observed in all species tested. Significant correlations between O 2 •− per cell and SOD activity per cell over growth phase were only observed in three raphidophytes ( Heterosigma akashiwo , Chattonella marina , and Chattonella antiqua strain 18), likely due to different cellular locations of externally released O 2 •− radicals and intracellular SOD enzymes measured in this study. CAT activity was greatest at early exponential phase for several raphidophytes, but correlations between H 2 O 2 per cell and CAT activity per cell were only observed for Fibrocapsa japonica Toriumi et Takano, Chattonella antiqua (strain 18), and Chattonella subsalsa Biecheler. Our results suggest that SOD and CAT play important protective roles against ROS during exponential growth of several raphidophytes, while other antioxidant pathways may play a larger role for scavenging ROS during later growth.