[Individual and joint stress of lead and mercury on growth, glutathione and glutathione-related enzymes of Scenedesmus quadricauda].
To understand the toxicity mechanisms of mixed heavy metals on aquatic plant, indicators of algea growth rate,content of reduced glutathione (GSH), activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx) of green algae, Scenedesmus quadricauda were measured to analyze the individual and joint toxic effects of lead and mercury. The results show that the 96h EC50 of algae growth inhibition by lead [Pb(NO3)2] and mercury (HgCl2) are 0.6789 mg/L and 0.1401 mg/L respectively. After 12 h individual and joint lead and mercury exposure, the content of GSH in alga cells is decreased to about 70% of the level of the control, and keeps a steady level with the increase of the exposure concentration. The GST activities are increased to a peak in lower concentration groups and then decrease with the increase of the exposure concentration. Indeed,the higher concentration of lead and mercury combined-poisoning can inhibit the activities of GST significantly, with 13.04% inhibitory rate. The activity of GPx is almost suppressed continuously with the increase of the exposure concentration, and the lowest activity is only 38.77% of the control. The toxic action of the mixture of Pb and Hg on growth inhibition,GSH content,activities of GST and activities of GPx for Scenedesmus quadricauda are addition.
Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. hjxyliyan@mail.nankai.edu.cn
Yan
Y
Li
Lin
L
Zhu
Shuo
S
Liu
D004347:Drug Interactions; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism*; D007854:Lead / Q000633:toxicity*; D008628:Mercury / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D044444:Scenedesmus / Q000201:enzymology / Q000254:growth & development*; D014874:Water Pollutants, Chemical / Q000633:toxicity
D014874:Water Pollutants, Chemical; D007854:Lead; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D008628:Mercury; D005978:Glutathione