铅胁迫对节杆菌(Arthrobacter sp.)和芽孢杆菌(Bacillus sp.)生理生化特性的影响

Impacts of Pb(Ⅱ) on the physio-biochemical features of Arthrobacter sp. and Bacillus sp.

将节杆菌和芽孢杆菌分别暴露于不同浓度的铅溶液中,并进行不同暴露时间的急性毒性试验。结果表明,500 mg/kg的Pb(II)处理会使节杆菌中的细胞膜脂质过氧化产物——硫代巴比妥酸活性物质(TBARS)浓度显著降低(p<0.05),而Pb(II)质量比变化对其他指标无显著影响(p<0.05);铅处理会使芽孢杆菌中可溶性蛋白质量浓度、GSH质量浓度和超氧化物歧化酶(SOD)活性显著升高,而过氧化氢酶(CAT)活性显著降低(p<0.05)。节杆菌的可溶性糖质量浓度、GSH质量浓度、SOD活性和TBARS浓度随暴露时间延长而显著增加;芽孢杆菌的可溶性糖质量浓度、GSH质量浓度和SOD活性随暴露时间延长而显著增加,TBARS浓度随暴露时间延长呈先增后减的变化趋势,CAT活性也表现出先增后降的变化趋势。铅处理对节杆菌和芽孢杆菌具有一定的胁迫作用,两种菌通过启动不同的抗性系统来抵抗外界胁迫。

This paper is engaged in a study of the effects of Pb（Ⅱ） on the physico-biochemical behaviors of Arthrobacter sp. and Bacillus sp. through toxicity testing. The toxicity test has been arranged by putting the antioxidant system of Arthrobacter sp. and Bacillus sp. in case of being exposed to the different concentrations of Pb（Ⅱ） for dif- ferent lengths of testing time. The results of our test show that Pb（Ⅱ） has a strong impact on the antioxidant system of Arthrobacter sp. and Bacillus sp. , though it is possible to reduce the TBARS content of Arthrobacter sp. significantly by letting Pb （Ⅱ） treated with 500 mg/kg. Nevertheless, no significant effect has been found by means of other indicators. Our testing results prove that it is possible to in- crease the soluble protein, the GSH content and the SOD activity of Bacillus sp. significantly by treating Pb（Ⅱ）, for it is possible to in- crease the time of exposure of the contents of the aforementioned com- pounds. On the contrary, it is also possible to increase the GSH con- tent and the SOD activity by means of prolonging the exposure, for the said soluble sugar contents tend to increase first and decrease lat- er, consequently. Besides, the protein has also been found decreased first and then increased. However, the increase of Pb（Ⅱ） concentra- tion proves to promote the SOD activity. What is more, Pb（It） is al- so found having effect on inducing Bacillus sp. Furthermore, it has also to be pointed out that the enhancement of SOD activity would like to result in a self-protective effect of the stress response. With the prolonging of exposure of Pb （Ⅱ） solution to Arthrobacter sp. and Bacillus sp. indifferent durations, it is favorable to increase the GSH content and SOD activity. Therefore, bacterial SOD and GSH synthe- sis has been found inducing metal toxicity. It is just for this reason that it is necessary for us to reduce the TBARS content to inhibit the soluble protein synthesis of Pb （II） ions with Bacillus sp.. Hence, the results of our testing demonstrate that the two kinds of bacteria can both be used in the different resistance systems for their resistant stress.