| Coal mining and utilization will release a lot of arsenic into the earth surface. Huainan is a typical city for coal resources, so it is of great environmental significance to carry out distribution research, source study, and speciation analysis of arsenic in Huainan soils. Arsenic poisoning can cause immune response and oxidative stress. Insulin pathway, evolutionarily conserved from yeast to mammals, can regulate innate immunity and oxidative stress.The research of arsenic stress resistance via insulin pathway is very useful for mitigating the effects of arsenic poisoning.According to the different utilization, Huainan soils were divided into industrial area, coal mining area, agricultural area and living area.The arsenic content in soils from different functional areas of Huainan was studied; the relationship between arsenic and the chemical nature of the soils were explored; the speciation of arsenic in soils were revealed, and the potential ecological and health risks were assessed. The anti-arsenic screening model was established by using C.elegans to propose the function and molecular mechanism of insulin pathway. First of all, we use heat shock to simulation "fever", activate the innate immune regulation function, observe the changes of arsenic tolerances, explore the mechanisms of daf-2、hsf-1、daf-16 gene and the responses of HSP-6、HSP-16.2、HSP-60'HSP-70. Next, we choose antioxidant capsaicin, take lifespan, survival time, ROS levels, lipofuscin accumulation physiological indexes, discuss the mechanisms of daf-2、hsf-1、daf-16 gene and the expressions of antioxidant enzymes superoxide dismutase-3(SOD-3)、Glutathione S transferase-4(GST-4) and Glutamine cysteine synthase-1(GCS-1). The major results can be summarized as follows:1. The content of arsenic varies vastly in different function areas, and increases in a sequence from industrial area, coal mining area, agricultural area and to living area, which is higher than Huainan soils background values and China soils background values. The artificial pollutions is the major source compared with the natural pollutions. The occurrence mode of arsenic in Huainan soils mainly exist in the state of residual and Fe-Mn oxidation., accounted for 48.3% and 21.5%, organic combination state, carbonate state and exchangeable state, accounted for 11.6%、11.0% and 7.6%, respectively. According to the risk assessment index method, the Huainan soils achieve the medium risk.2. Potential ecological risk and health risk posed by arsenic in different functional areas were at high levels. The results of potential ecological risk index showed that due to the coal mining, transportation and utilization, industrial area and coal mining area were exposed to high-level pollution. The results of health risk assessment showed that arsenic content in the industrial area was far beyond the acceptable risk limit. Special attention should be paid to industrial area and coal mining area.3. Heat shock can activate the insulin pathway to regulate innate immunity. With utilization of nematodes as model organism,48h LC50 show heat shock enhances 51.0% immune response against arsenic. The resistance of hsf-1、daf-16、hsp-4' hsp-16.2 mutants were reduced. Over-expression of HSF-1 can restore the tolerance level under arsenic exposure. Heat shock improved the time and rate of DAF-16 nuclear localization and enhanced the activity of insulin pathway crucial transcription factor DAF-16 and downstream HSPs expression. Meanwhile, heat shock reduced protein misfolding from endoplasmic reticulum and mitochondria.4. Capsaicin can activate the insulin pathway to regulate oxidative stress. With oxidative stress triggered by Arsenic as the starting point, capsaicin can extend survival time, reduce ROS level and lipofuscin accumulation and delay aging. It indicated that DAF-16 and SKN-1 maybe involved in the antioxidant mechanism of capsaicin. SOD-3, GST-4 and GCS-lwere inhibited in arsenic-exposed group, while in capsaicin-treated group, they were improved significantly.Based on this research, we should pay more attention to soils arsenic pollution of the industrial area and coal mine area in Huainan, and support application of capsaicin as an auxiliary treatment after arsenic exposure. Furthermore, we also need to monitor the arsenic pollution in these areas and carry out genetic screening work of arsenic stress resistance positively. The research provided a scientific basis and theoretical basis for the prevention and treatment of arsenic poisoning. |
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