Growth Inhibition and Oxidative Stress Caused by 4,4'-dibromodiphenyl Ether (BDE-15) on a Marine Diatom Phaeodactylum Tricornutum

Abstract

In this work, Phaeodactylum tricornutum was used to investigate the toxicity of 4,4'-dibromodiphenyl ether (BDE-15). Results showed that BDE-15 inhibited the photosynthetic activity and growth of P. tricornutum significantly with 24, 48, 72, and 96 h EC50 values of 1.03, 0.44, 0.41, and 0.42 mg L-1, respectively, indicating that it was a highly toxic substance. Moreover, BDE-15 could cause cell deformation, and a series of physiological, biochemical, and molecular changes in the cells. Under the exposure of BDE-15, contents of chlorophyll a and soluble protein decreased significantly, but reactive oxygen species (ROS) were accumulated in the algal cells, which may cause or intensify the peroxidation of membrane lipids. For alleviating the toxicity of excessive ROS, activities of antioxidant enzymes increased dramatically when this diatom was exposed to BDE-15. Thus, it is concluded that the overproduction of ROS may be regarded as one of the major factors in BDE-15 toxicity.