借助生物工程技术，科学家将一种细菌“改造”出亲汞特性，希望借助这种转基因细菌帮助消除环境中的汞污染。
工业排放、金矿开采等人类活动极易给水和土壤环境造成汞污染。经由食物链，特定地区的汞污染威胁人类健康，而现有清除环境汞污染的方法成本异常高昂。
美国泛美波多黎各大学一个生物工程研究团队向一种埃希氏大肠杆菌内注入两种“亲汞”基因。两种基因转入埃希氏大肠杆菌体内后，分别生成一种名为金属硫蛋白的蛋白质和一种名为多磷酸盐激酶的生物酶。
金属硫蛋白和多磷酸盐激酶可有效固定进入大肠杆菌体内的金属物质，防止细胞中毒。
而后，研究者将两种转基因埃希氏大肠杆菌置入含有高剂量汞的营养液，结果发现，生成多磷酸盐激酶的转基因大肠杆菌的抗汞能力是普通大肠杆菌的16倍，而生成金属硫蛋白的转基因大肠杆菌的这一倍率则高达24倍。
在营养液内存活5天后，两种转基因大肠杆菌“吞噬”大约八成环境中的汞。
法新社8月16日援引研究团队的话报道，这种转基因大肠杆菌有望成为消除环境汞的新工具。尽管眼下团队尚未评估实际运用时的成本，但应当大大低廉于现有清除环境汞污染技术每千克10万美元至15万美元的耗费。
转基因大肠杆菌可协助清除环境汞污染
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The bacteria that ate mercury
SCIENTISTS have engineered bacteria that can mop up mercury, a step towards using "bioremediation" to cleanse toxic chemicals from the environment.
Mercury pollution of water and soil by industrial spills or goldmining is a significant hazard because the chemical accumulates up the food chain, and tackling the problem is prohibitively expensive.
A team led by Oscar Ruiz of the Inter-American University of Puerto Rico said they inserted two mercury-friendly genes into the common intestinal germ, Escherichia coli. The genes controlled a protein called metallothionein and an enzyme known as polyphosphate kinase, both of which bind to metals to prevent toxicity in cells.
The researchers immersed the engineered bugs in a nutrient solution to which high doses of mercury had been added.
After five days, the germs were spun in a centrifuge.
Chemical analysis showed the bacteria had absorbed up to 80 per cent of the mercury to which they had been exposed, BMC Biotechnology reported.
Mr Ruiz said the work could lead to a way not only to clean up mercury but also to recycle it, using electrochemistry to extract the chemical from the bacteria.
