稻田土壤细菌对重金属镉的氧化应激反应研究

研究重金属镉胁迫下稻田土壤大肠杆菌K12、枯草芽孢杆菌B19及Ralstonia eutropha DKC1中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和ATP酶活性等应激酶活性的短期(46 h)变化.结果表明,不同浓度镉对E.coli K12,B.subtilisB19和R.eutrophaDKC1培养不同时间的SOD、CAT和ATP酶活性均有不同程度的诱导作用,表现在前期、低浓度时激活,后期、高浓度时抑制,体现了不同微生物间的差异以及抗镉潜力的不同.3种指标间接地反映了环境中有毒有害物质的存在,且能在早期较灵敏地指示污染的影响,作为环境受到污染胁迫的细胞生化指标具有一定可行性.

Response of bacteria in oxidative stress by Cd

The present article introduces the authors' study on the physiological toxicity of Cd~(2+) to SOD, CAT and ATPase enzyme activities of \%Escherichia coli\% K12, \%Bacillus subtilis\% B19 and \%Ralstonia eutropha\% DKC1 through pure bacteria cultivation, because such activities are typical microbial species in submerged paddy soil when they are exposed to Cadmium (Cd) in short term (about 46 h). The results show that the influence of Cd~(2+) on the SOD, CAT and ATPase activities of bacteria was various. According to our observation, different concentrations of cadmium may appear to have different derivational effects on the three enzyme activities of \%E.coli\% K12, \%B. subtilis\% B19 and \%R. eutropha\% DKC1 at the different growing stages. They would keep activated when exposed to low concentrations of cadmium or at the earlier growth stage, nevertheless, they were inhabited when done to higher concentrations of cadmium or at the latter growth stage, which suggest the difference and the potential to resist cadmium among different bacteria. The above three mentioned enzyme activities could report indirectly the existence of noxious substance in environment, sensitively indicating the effect of Cd contamination. Therefore, the result may account for the physiological toxicity of the typical microbial species from Cd~(2+) and therefore can be used as cell biochemical index to indicate the Cd contamination.