[Toxic effects of high concentrations of ammonia on Euglena gracilis].
Ammonia is among the common contaminants in aquatic environments. The present study aimed at evaluation of the toxicity of ammonia at high concentration by detecting its effects on the growth, pigment contents, antioxidant enzyme activities, and DNA damage (comet assay) of a unicellular microalga, Euglena gracilis. Ammonia restrained the growth of E. gracilis, while at higher concentrations, ammonia showed notable inhibition effect, the growth at 2 000 mg x L(-1) was restrained to 55.7% compared with that of the control; The contents of photosynthetic pigments and protein went up with increasing ammonia dosage and decreased when the ammonia concentration was above 1000 mg x L(-1); In addition, there was an obvious increase in SOD and POD activities, at higher concentration (2 000 mg x L(-1)), activities of SOD and POD increased by 30.7% and 49.4% compared with those of the control, indicating that ammonia could promote activities of antioxidant enzymes in E. gracilis; The degree of DNA damage observed in the comet assay increased with increasing ammonia concentration, which suggested that high dose of ammonia may have potential mutagenicity on E. gracilis.
State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China. huohuoliuyan@163.com
Yan
Y
Liu
State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Xiao-Rong
XR
Shi
State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Yi-Bin
YB
Cui
State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Mei
M
Li
D000641:Ammonia / Q000633:toxicity*; D020552:Comet Assay; D004249:DNA Damage; D005056:Euglena gracilis / Q000187:drug effects*; D009153:Mutagens; D010788:Photosynthesis; D013482:Superoxide Dismutase; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D009153:Mutagens; D014874:Water Pollutants, Chemical; D000641:Ammonia; D013482:Superoxide Dismutase