首页|Toluene induces hormetic response of soil alkaline phosphatase and the potential enzyme kinetic mechanism

Toluene induces hormetic response of soil alkaline phosphatase and the potential enzyme kinetic mechanism

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  • NSTL
  • Elsevier
Hormesis of soil enzyme that involved in heavy metal has been attracting much more attention for risk assessment of heavy metal toxicity, but insufficient studies were conducted to define the hormetic responses induced by toluene or other organic pollutions. The objectives of this study were to investigate the hormetic responses of soil enzyme induced by toluene and explore the potential enzyme kinetic mechanism. Soil alkaline phosphatase (ALP) activity was regarded as the endpoint to explore the hormetic responses under different doses of toluene (0.0, 0.1, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 50.0 and 100.0 mu L g(-1)). Subsequently, we conducted the experiments of enzymatic reaction kinetics and pure enzyme to further verify the potential mechanisms of soil ALP's hormesis. Results showed that ALP activities at 0.1-1.0 mu L g(-1) toluene were significantly increased in contrast to the control (0 mu L g(-1) toluene) (P < 0.05) at the exposure time of 30, 36, 48 and 54 h, with the maximum stimulation magnitudes of 24-43%. ALP activities were almost not affected by toluene (2-100 mu L L-1) in the whole experimental period (6-54 h). Meanwhile, the values of catalytic efficiency (the radio V-max/K-m, V-max: maximum reaction velocity and K-m: Michaelis constant) and V-max significantly increased compared with the control, but the value of K-m decreased from 2.5 to 1.6. Overall, low dose toluene can induce hormesis of soil ALP. The potential reason is that low-dose toluene could enhance the combination of soil ALP and substrates. We believe that this study will provide a new viewpoint for ecological risk assessment of toluene contaminated soils.

HormesisSoil alkaline phosphataseTolueneEnzymatic reaction kineticEcological risk assessment

Fan, Diwu、Jing, Yujing、Zhu, Yongli、Ahmad, Sajjad、Han, Jiangang

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Nanjing Forestry Univ, Coll Biol & Environm, Nanjing 210037, Peoples R China

Jiangsu Univ, Coll Environm & Safety Engn, Zhenjiang 212013, Jiangsu, Peoples R China

Nanjing Forestry Univ, Collaborat Innovat Ctr Sustainable Forestry South, Nanjing 210037, Peoples R China|Nanjing Forestry Univ, Coll Biol & Environm, Nanjing 210037, Peoples R China

Univ Nevada, Dept Civil & Environm Engn, Las Vegas, NV 89154 USA

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2020

10.1016/j.ecoenv.2020.111123

Ecotoxicology and environmental safety

Ecotoxicology and environmental safety

ISSN：0147-6513
年,卷(期)：2020.206(Dec.)
  • 8
  • 52