Changes in Electrophoretic Profiles of Proteins and Some Antioxidant Enzymes in Antarctic Alga Choricystis Minor and Chlorella Sp. as Affected by Temperature and Oxidative Stress

ABSTRACT

The change in electrophoretic profiles of polypeptides and isoenzymes of superoxide dismutase (SOD) and (CA) as affected by extreme temperature and the strong oxidant Sanosil were studied. The temperature (T^o) stress in Antarctic alga Choricystis minor and Chlorella sp. was caused by treatment with high T^o. The oxidative stress was caused by adding the algicide Sanosil which generates H₂O₂ in the nutrient medium. The influence of both types of stress was investigated by treatment with high T^o as well as in combination with Sanosil. The stress factors applied caused slight quantitative alterations in profiles of polypeptides in Chlorella cells. The presence of Sanosil in the medium decreased the polypeptide amounts in Choricystis cells as well as in high T^o-treated cells. The high T^o alone increased the amount of available polypeptide bands and the appearance of new bands occurred. In Choricystis cells two new CA isoenzymes appeared under the treatment of high T^o and Sanosil. High T^o alone caused slight decrease in CA activity. In high T^o treated Choricystis cells slight increase in SOD activity was observed. In Chlorella cells a new CA isoenzyme appeared under the influence of high T^o. At the low T^o Sanosil decreased the intensity of this band. New isoenzymes of SOD appeared in high T^o and Sanosil treated variants. In Chlorella high T^o increased the SOD activity. At the low T^o Sanosil caused the same effect as after treatment with high T^o.

Keywords:

• green algae
• catalase
• superoxide dismutase
• oxidative stress
• temperature stress