Difference between revisions of "Team:FAFU-CHINA"

    Continued worldwide industrialization has caused extensive environmental and human health problems. A wide variety of chemicals, e.g., heavy metals, pesticides, chlorinated solvents, etc., have been detected in different natural resources such as soil, water, and air. Among the pollutants, the heavy metals are of concern to human health due to their cytotoxicity,mutagenicity, and carcinogenicity.
    Soil polluted by heavy metals represent an important environmental problem due to the toxic effects of metals, their accumulations throughout the food chain and the additional risk of groundwater contamination.
    Metal remediation through common physico-chemical techniques is expensive and unsuitable in the case of extensive areas. Therefore biotechnological approaches have received a great deal of attention in recent years. Bioremediaton, as a way of natural attenuation, adds phytoremediation, the use of plants for reclamation and microbe(PSB) together as a strategy for either enhancing uptake(PSB-assisted Phytoextraction) or reducing the bioavailability of metal contaminants(PSB-immobilized Phyto-promotion mechanism) in the soil, especially in the rhizosphere to accelerate plant biomass production and root enlongation.

    In this module, our team designed a pathway that the Pb ions will bind to PbR protein when activated ions are in the soil environment. It induces downstream gene expression, and results in the tetR protein inhibition promoter PltetO1 expression. At the same time, the strong promoter P43 of B.megaterium stimulated the expression of MBP in the downstream lead-producing peptide. It makes the chelating peptide of Pb metal, which reduced the total amount of heavy metals in the soil to be harmless level. When there is no Pb ions presented in the environment, the expression of tetR was blocked and the inhibition of PltetO1 was released. It results in the lacI repressor binding to the lacO sequence, and leads to blocking the expression of MBP. This mechanism is effective in preventing the infinite expression of MBP against the B. megaterium itself.