细菌对重金属的抗性及解毒机理研究进展

On the research advances of the resistance and de-toxicity power of bacteria from heavy metals

重金属污染物随工业废水排放到环境中,并通过生物链的富集作用,对环境和人类健康造成极大危害。自然界中很多微生物对重金属具有吸附性、耐受性和减小毒性损伤的特点。其中,细菌因其结构简单且易于培养,被广泛应用于研究对重金属的抗性及解毒。选取银(Ag)、铜(Cu)、铅(Pb)和铬(Cr)4种重金属,结合国内外的研究成果,系统地探讨了细菌对重金属的抗性及解毒机理。

The present paper aims to introduce some mechanisms on the resistance and de-toxic power against the heavy metal contamination in bacteria.As is known,the fast expansion of industrial scale and the multiplicity of industrial products have brought about more and more serious environmental problems that are threatening the human living condition and public health for the vast social members.The ever increasing serious environment pollution and the ecological damage have mainly been brought about by heavy metals and other industrial wastes and emissions discharged into the water bodies and farmland soils.However,some microorganism which was absorbable and detoxifies this poisons to attenuation the toxic of heavy metal in environment.Therefore,we would like to focus our exploration to disclose some molecular mechanisms of heavy metals potential resistance in bacteria.In the paper,we have chosen four heavy metals,that is,silver（Ag）,copper（Cu）,lead（Pb） and chromate（Cr）,which can be the objects for the bacteria to resist and detoxify.The said mechanism or function may include ABC-transport system,the oxidation-reduction reactions,the complex reactions and so on.It is more attractive for us researchers that there exist different mechanisms matching between the heavy metals and the microorganisms.In addition,even for the same kind of heavy metal ion in a certain microorganism,there may be different mechanisms.Another example is the resistance and de-toxic power of Ag,which may have three main models,that is,some proteins fixed Ag~＋,ABC transport system and some extracellular substance fixed Ag~＋ to result from the inorganic chemical reaction.The same is with Pb.But resistance and de-toxicity of Cu can be of the reduction-oxidation reaction and ABC transport system.On the other hand,the resistance and de-toxicity of Cr may also involve substitution by the metabolic regulation of iron-sulfur protein.Therefore,in order to discover resistance and de-toxicification of heavy metals in bacteria,it is recommended to adopt some suitable ways to the sample,though the best approach is a combined method with some other means.In doing so,it is critical to have a sound knowledge of the detailed mechanisms of resistance and de-toxicification.Hence,this paper can be regarded as a basis for further study on the structure mechanism and gene-cloning engineering.