Tylosin Inhibited Growth of Chlorella Vulgaris and Raphidocelis Subcapitata by Inducing Oxidative Stress

Abstract

Two model algae Chlorella vulgaris (C. vulgaris) and Raphidocelis subcapitata (R. subcapitata) were generally used to test chemicals with antimicrobial properties during registration process. However, it has been reported that significant sensitivity difference in two algae when exposure to antibiotics. Furthermore, the selection of an appropriate test species play a vital role in evaluate of environmental hazards and risks of compounds. Since the balance between oxidative stress and antioxidant is a crucial factor on alga growth. This experiment is performed to investigate the working of oxidative stress and mechanism of antioxidant defense system of algae under antibiotic stress. A series of concentration of Tylosin (TYN), a macrolide antibiotic, were used to test in this study. Oxidative stress biomarkers (Malondialdehyde (MDA)), non-enzymatic antioxidants (Reduced glutathione (GSH)), antioxidant enzymes (Superoxide dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GP), Glutathione S-transferase (GST)) and photosynthetic pigments were measured to investigate antioxidant defense system. R. subcapitata was significantly inhibited with increasing concentration of TYN, whereas no effects on C. vulgaris. The contents of MDA increased significantly when species were inhibited, and thus, activating the antioxidant system, companying with the significantly increasing of SOD and CAT.