The Cd resistant mechanism of Proteus mirabilis Ch8 through immobilizing and detoxifying.

Cadmium (Cd) pollution is a serious global environmental problem, which requires a global concern and practical solutions. Microbial remediation has received widespread attention owing to advantages, such as environmental friendliness and soil amelioration. However, Cd toxicity also severely deteriorates the remediation performance of functional microorganisms. Analyzing the mechanism of bacterial resistance to Cd stress will be beneficial for the application of Cd remediation. In this study, the bacteria strain, up to 1400 mg/L Cd resistance, was employed and identified as Proteus mirabilis Ch8 (Ch8) through whole genome sequence analyses. The results indicated that the multiple pathways of immobilizing and detoxifying Cd maintained the growth of Ch8 under Cd stress, which also possessed high Cd extracellular adsorption. Firstly, the changes in surface morphology and functional groups of Ch8 cells were observed under different Cd conditions through SEM-EDS and FTIR analyses. Under 100 mg/L Cd, Ch8 cells exhibited aggregation and less flagella; the Cd biosorption of Ch8 was predominately by secreting exopolysaccharides (EPS) and no significant change of functional groups. Under 500 mg/L Cd, Ch8 were present irregular polymers on the cell surface, some cells with wrapping around; the Cd biosorption capacity exhibited outstanding effects (38.80 mg/g), which was mainly immobilizing Cd by secreting and interacting with EPS. Then, Ch8 also significantly enhanced the antioxidant enzyme activity and the antioxidant substance content under different Cd conditions. The activities of SOD and CAT, GSH content of Ch8 under 500 mg/L Cd were significantly increased by 245.47%, 179.52%, and 241.81%, compared to normal condition. Additionally, Ch8 significantly induced the expression of Acr A and Tol C (the resistance-nodulation-division (RND) efflux pump), and some antioxidant genes (SodB, SodC, and Tpx) to reduce Cd damage. In particular, the markedly higher expression levels of SodB under Cd stress. The mechanism of Ch8 lays a foundation for its application in solving soil remediation.

[Huaier triggering mitochondria apoptosis in colorectal cancer cells through oxidative stress].

This study investigates the specific mechanisms of Huaier-induced mitochondrial apoptosis in colorectal cancer. HCT116 and SW480 cells were subjected to Huaier treatment. Cell proliferation and migration capabilities were examined through CCK-8 and scratch experiments, respectively. Apoptotic cells were clarified with Annexin-PE staining. DCFH-DA staining, malondialdehyde(MDA), and glutathione(GSH) were used to evaluate the oxidative stress damage level of cells. MitoSOX and JC-1 probes were used to selectively target mitochondria reactive oxygen species(mtROS) and mitochondria membrane potential(MMP) for the evaluation of mitochondria damage. Western blot(WB) experiment was performed to determine apoptosis proteins and PINK1/Parkin pathway. Experiments reveal that in different concentrations of Huaier treatment, the proliferation and migration capabilities of HCT116 and SW480 cells were both restrained. Additionally, mitochondrial apoptosis was activated. Compared with the control group, excessive ROS in colorectal cancer cells was generated in the Huaier group, while MDA increased, and GSH decreased, indicating oxidative stress damage. mtROS increased, and MMP decreased in colorectal cancer cells treated with Huaier, indicating mitochondrial damage. WB result revealed that Huaier suppressed the PINK1/Parkin pathway, hindered the clearance of impaired mitochondria, and subsequently facilitated apoptosis. In conclusion, Huaier impairs colorectal cancer cells through oxidative stress and mitochondria damage. Furthermore, it suppressed the PINK1/Parkin pathway, promoting mitochondria apoptosis in colorectal cancer cells.