邻苯二甲酸二甲酯对典型细菌生长和氧化应激酶系的影响

Impact of Dimethyl Phthalate on the Activities of Oxidative Stress Enzymes and Growth of Typical Bacteria

邻苯二甲酸二甲酯(DMP)是一种在环境中广泛存在的有毒有机化合物,已被中国列为优先控制污染物之一。为研究邻苯二甲酸二甲酯(DMP)对典型细菌的影响,将Bacillus subtilis B19(G+)和Escherichia coli K12(G-)暴露于含不同浓度DMP(0,5,10,20,40和80 mg·L-1)的培养基中,监测它们的生长状态以及氧化应激酶系的变化。结果表明:DMP能抑制细菌生长,且其抑制作用随DMP的浓度增大而增强。在相同的实验条件下,DMP对Escherichia coli K12的抑制作用比Bacillus subtilis B19更为显著,且会使菌体的长度增加。随着DMP浓度的逐渐增高,菌体内的SOD、CAT和GST的活性也随之上升。这一现象表明菌体内的ROS浓度有所升高。通过观察DMP的作用浓度及对时间的效应过程,发现菌体内的酶活性呈现低浓度促进,高浓度抑制的趋势,并伴随出现氧化应激反应,该研究结果为进一步研究DMP对微生物的影响提供了重要基础。

Dimethyl phthalate （DMP）, one of the phthalate esters, is ubiquitous environmental pollutant. It has been listed as an environmental priority pollutant by China State Environmental Protection Administration （SEPA）. To study the impacts of dimethyl phthalate contamination on the activities of oxidative stress enzymes and growth of typical bacteria, Escherichia coli K12 （a gram-negative bacterium） and Bacillus subtilis B 19 （a gram-positive bacte- rium） were exposed to the conditions with various DMP concentrations （0, 5, 10, 20, 40 and 80 mg ~ L-1, respective- ly）, and observed the status of their growth as well as monitored the enzyme activities. The results showed that the growth of Escherichia coli K12 and Bacillus subtilis B19 were inhibited by DMP. Under the equal conditions, it was more effective in E. coli K12 than in Bacillus subtilis B19. The evidences from electron microscopy （SEM） showed that DMP pollution increased the length of thallus for the two strains. In the meantime, the activities of SOD, CAT and GST in the two strains were increased along with the increase of DMP concentration, which meant that the con-centration of ROS raised up in the bacteria. Additionally, the phenomenon implies that the oxidative stress reaction was triggered by DMP contamination in bacteria. We propose that our results provided solid evidences for the fur- ther studies on the impact of dimethyl phthalate contamination on soil bacteria.