| Biography | |
|---|---|
 Dr. Jiqiu Li South China Normal University, China |
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| Title: Ecotoxicity assessment of fishery antibiotic by using protozoa as model organism | |
| Abstract:
With the intensive development of the aquaculture industry, the use of fishery antibiotics increased sharply. At present, antibiotics have been one of the main pollutants in the aquaculture environment. Ecotoxicity evaluation of antibiotics can provide important theoretical support for the sustainable development of aquaculture. Protozoa have been internationally recognized as an ideal indicator of water quality deterioration, because of their special biological properties and their important roles in ecological function and status in the water environment. However, studies on the evaluation of ecological toxicity induced by antibiotics by using protozoa as model organisms are still lacking.
In order to evaluate the ecotoxicity of antibiotic nitrofurazone, the exposure of nitrofurazone (factors involving dosage, exposure duration, species-specificity and so on) on biological response patterns were systematically studied by using protozoa as model organisms from different biological levels, including population, individual, molecular and gene levels.
The findings include: 1) RAPD expression patterns were determined in the tested protozoa for evaluating the nitrofurazone induced genotoxicity. Results demonstrated the potential of the RAPD assay as a powerful tool for detecting the genotoxicity of fishy nitrofurazone in the aquatic environment; 2) Genotoxicity was evaluated in the ciliated protozoa, Euplotes vannus and Pseudokeronopsis rubra, when exposed to graded doses of nitrofurazone for several discrete durations. Results confirmed nitrofurazone-induced genotoxicity and the important role of organism-specific factors in the selection of model organisms from ciliated protozoa for environmental monitoring and risk assessment for aquaculture; 3) Using antioxidant enzyme activity and its gene expression level as biomarkers, the effects of nitrofurazone dose and exposure duration on biological response patterns were determined in the tested protozoa. Results confirmed the potential of the antioxidant enzymes to be used as biomarkers to evaluate the ecotoxicity of nitrofurazone. However, differences among biomarkers were significant in the response patterns, which were affected by the dose of nitrofurazone, exposure duration and the determined endpoints; and the importance of dynamics and piecewise function was demonstrated in dose response pattern analysis.
In conclusion, the above results confirmed the ecotoxicity of antibiotic nitrofurazone and the feasibility of protozoa as an indicator of ecotoxicology. At the same time, it provides important theoretical support for the establishment of the index system for evaluating ecotoxicity of antibiotics with protozoa as indicator.
Finally, it is necessary for future research to use new research tools and more powerful mathematical statistical analysis methods to integrate biological responses from different levels of biological organization (determined endpoints), and to establish the relationships between biological response patterns and environmental pollutant dosages for practical application in environmental monitoring and risk assessment.
Key words: Ecotoxicity assessment; Fishery antibiotic; Protozoa; Model organism
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