ABSTRACT
Toxoplasmosis is one of the most common parasitic infections of humans and other mammals. This study was aimed to understand the mechanism of action of veterinary medicine-sulfachloropyrazine [SPZ, 99.97%] against Toxop/asma gondii. T. gondii tachyzoites were soaked in PBS [as a control] or SPZ [250 mg/mL] for 2 h at 37 °C. After being processed, any ultrastructural changes of the tachyzoites that had occurred were observed by Scanning Electron Microscopy [SEM] and Transmission Electron Microscopy [TEM]. The tachyzoites from control groups with a uniform size had a smooth surface and intact cell or nuclear membranes. In addition, an oval-shaped nucleus, conoids and micronemes were also observed. By contrast, many parasites from the SPZ-treated groups were detrimentally affected by the treatment. Some appeared to be of the vacuolization in their cytoplasm, with the substantial reduction in the number of dense granules and the blur of some organelles. The morphology and ultrastructure of tachyzoites can be affected significandy by SPZ, which might kill the parasite by inhibiting its energy metabolism, inducing apoptosis and damaging its structure. The study provides an experimental basis for further study on the mechanism of SPZ against T. gondii
ABSTRACT
This research describes application of laccase from white-rot fungi [polyporus] to remove dichlorodiphenyltrichloroethane in soil. The degradation kinetics of dichlorodiphenyltrichloroethane in soil was also investigated by laboratory batch experiments. The results showed that laccase from white-rot fungi can effectively degrade dichlorodiphenyltrichloroethane and the degradation of total dichlorodiphenyltrichloroethane [the sum of the four dichlorodiphenyltrichloroethane compounds in a sample] was pseudo-first-order kinetics. The residues of almost all the dichlorodiphenyltrichloroethane components and total dichlorodiphenyltrichloroethane in soils treated with laccase decreased rapidly during first 15 days and then kept at a stable level during next 10 days. The residues of total dichlorodiphenyltrichloroethane in soils with different dosages laccase decreased by about 21-32%, 29-45%, 35-51% and 36-51% after 5, 10, 15 and 25 days of incubation, respectively. The half-life of total dichlorodiphenyltrichloroethane in soils with different dosages laccase ranged from 24.75 to 41.75 days. The residues of total dichlorodiphenyltrichloroethane in three different types of soils decreased by 25-29%, 39-43%, 44-47% and 47-52% after 5, 10, 15 and 25 days of incubation with laccase, respectively. The half-life of total dichlorodiphenyltrichloroethane in different types of soil ranged from 24.71 to 27.68 days. The residues of total dichlorodiphenyltrichloroethane in soils with different pH levels decreased by 18-24%, 29-39%, 36-39% and 39-50% after 5, 10, 15 and 25 days of incubation with laccase, respectively. The half-life of total dichlorodiphenyltrichloroethane ranged from 25.63 to 36.42 days. Laccase can be an efficient and safe agent for remediation of dichlorodiphenyltrichloroethane-contaminated soil