Cobalt and manganese stress in the microalga Pavlova viridis(Prymnesiophyceae): Effects on lipid peroxidation and antioxidant enzymes
LI Mei , ZHU Qin , HU Chang-wei , CHEN Li , LIU Zhi-li , KONG Zhi-ming
DOI:
Received January 23, 2007,Revised April 26, 2007, Accepted , Available online
Volume 19,2007,Pages 1330-1335
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Pollution of marine environment has become an issue of major concern in recent years. Serious environmental pollution by heavy
metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine
environment and accumulated without decomposition. The aim of the present study is to investigate the e ects on growth, pigments,
lipid peroxidation, and some antioxidant enzyme activities of marine microalga Pavlova viridis, in response to elevated concentrations
of cobalt (Co) and manganese (Mn), especially with regard to the involvement of antioxidative defences against heavy metal-induced
oxidative stress. In response to Co2+, lipid peroxidation was enhanced compared to the control, as an indication of the oxidative
damage caused by metal concentration assayed in the microalgal cells but not Mn2+. Exposure of Pavlova viridis to the two metals
caused changes in enzyme activities in a di erent manner, depending on the metal assayed: after Co2+ treatments, total superoxide
dismutase (SOD) activity was irregular, although it was not significantly a ected by Mn2+ exposure. Co2+ and Mn2+ stimulated the
activities of catalase (CAT) and glutathione (GSH), whereas, glutathione peroxidase (GPX) showed a remarkable increase in activity in
response to Co2+ treatments and decreased gradually with Mn2+ concentration, up to 50 mol/L, and then rose very rapidly, reaching to
about 38.98% at 200 mol/L Mn2+. These results suggest that an activation of some antioxidant enzymes was enhanced, to counteract
the oxidative stress induced by the two metals at higher concentration.
