Mishra Seema, Tripathi R D, Srivastava Sudhakar, Dwivedi Sanjay, Trivedi Prabodh Kumar, Dhankher O P, Khare A
Ecotoxicology and Bioremediation Group, National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India.
Bioresour Technol. 2009 Apr;100(7):2155-61. doi: 10.1016/j.biortech.2008.10.041. Epub 2008 Dec 16.
In the present study, the level of thiols and activity of related enzymes were investigated in coontail (Ceratophyllum demersum L.) plants to analyze their role in combating the stress caused upon exposure to cadmium (Cd; 0-10 microM) for a duration up to 7d. Plants showed the maximum accumulation of 1293 microg Cd g(-1)dw after 7d at 10 microM. Significant increases in the level of total non-protein thiols (NP-SH) including phytochelatins (PCs) as well as upstream metabolites of the PC biosynthetic pathway, cysteine and glutathione (GSH) were observed. In addition, significant increases in the activities of cysteine synthase (CS), glutathione-S-transferase (GST), glutathione reductase (GR), as well as in vitro activation of phytochelatin synthase (PCS), were noticed in response to Cd. In conclusion, under Cd stress, plants adapted to a new metabolic equilibrium of thiols through coordinated synthesis and consumption to combat Cd toxicity and to accumulate it.
在本研究中，对金鱼藻（Ceratophyllum demersum L.）植株中的硫醇水平和相关酶活性进行了研究，以分析它们在抵御暴露于镉（Cd；0 - 10微摩尔）长达7天所引起的胁迫中的作用。在10微摩尔浓度下处理7天后，植株中镉的最大积累量达到1293微克/克干重。观察到包括植物螯合肽（PCs）以及PC生物合成途径的上游代谢物半胱氨酸和谷胱甘肽（GSH）在内的总非蛋白硫醇（NP - SH）水平显著增加。此外，还注意到半胱氨酸合酶（CS）、谷胱甘肽 - S - 转移酶（GST）、谷胱甘肽还原酶（GR）的活性显著增加，以及植物螯合肽合酶（PCS）的体外活性增强，以响应镉胁迫。总之，在镉胁迫下，植物通过协调合成和消耗来适应硫醇的新代谢平衡，以对抗镉毒性并积累镉。
