Ultraviolet irradiation induced oxidative stress and response of antioxidantsystem in an intertidal macroalgae Corallina o cinalis L.
Lixia Li , Jiqiang Zhao , Xuexi Tang
DOI:
Received July 21, 2009,Revised December 22, 2009, Accepted , Available online
Volume 22,2010,Pages 716-722
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The response of the antioxidant defense system of an intertidal macroalgae Corallina o cinalis L. to di erent dosages of UV-B
irradiation was investigated. Results showed that superoxide dimutase (SOD) and peroxidase (POX) increased and then maintained
at a relatively stable level when subjected to UV-B irradiation. Catalase (CAT) activity under medium dosage of UV-B irradiation
(Muv) and high dosage of UV-B irradiation (Huv) treatments were significantly decreased. Ascorbate peroxidase (APX) activity first
remained unaltered and then increased in Huv treatment. In addition, the assay on isozymes was carried out using non-denaturing
polyacrylamide gel electrophoresis (PAGE). The activities of some SOD isoforms were altered by UV-B. Two new bands (POX V and
POX VII) appeared upon exposure to all three UV-B dosages. CAT III activity was increased by low dosage of UV-B irradiation (Luv),
whereas CAT III and CAT IV disappeared when the alga was exposed to Muv and Huv. Two bands of APX (APX VI and APX VII)
were increased and a new band (APX X) was observed under Huv exposure. H2O2 and thiobarbituric acid reacting substance (TBARS)
increased under Muv and Huv treatments. Overall, UV-B protection mechanisms are partly inducible and to a certain extent su cient
to prevent the accumulation of damage in C. o cinalis.
