Degradation and adsorption of tralkoxydim in Chinese soils and water-sediment environments.

Tralkoxydim is a cyclohexanedione herbicide primarily used for gramineous weed control in China. In this paper, we present results of a tralkoxydim laboratory environmental fate study characterizing its degradation, adsorption, and mobility behavior in three different soils and two water-sediment systems (river and lake) in China. Degradation half-life of tralkoxydim in soil under aerobic conditions was 5.1, 7.7, and 7.9 days in Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Under anaerobic and flooding conditions, half-life values were 6.2, 15.1, and 19.8 days for the same three soils, respectively. Soil pH was the major factor effecting tralkoxydim degradation. In the aerobic water-sediment experiments, tralkoxydim degraded faster in the river system (total system half-life 43.3 days) than the lake system (total system half-life 99.0 days). Correspondingly, its anaerobic degradation half-life values were 46.2 and 53.3 days for the river and lake systems, respectively. Tralkoxydim adsorption in the three soils was found to follow the empirical Freundlich isotherm. The adsorption coefficient (K d ) was 8.60, 1.00, and 1.57 for Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Soil pH was the major factor effecting tralkoxydim adsorption. Adsorption free energy change was less than 40 kJ mol-1 in all three soils, indicating a physical mechanism in the process. Thin-layer chromatography (TLC) tests showed that relative to the solvent transport to 11.5 cm, the travel distance of tralkoxydim was 8-10 cm in the three soils, corresponding Rf values at 0.05, 0.35, and 0.75 for Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Results of this work suggest that under alkaline conditions, tralkoxydim adsorption becomes smaller; thus, assessments on its mobility and potential groundwater impact should focus on these soil types.

Influence of overexpression of SOCS2 on cells of DN rat.

OBJECTIVE: To explore the influence and mechanism of overexpression of SOCS2 on diabetic nephropathy (DN) rats and cells. METHODS: STZ was used to induce male SD rats and SOCS2 was injected into left renal vein. Rats were divided into DN group, DN-Ad-null group and DN-Ad-SOCS2 group. Glucose with high and normal concentration was used to culture HBZY-1 cells and then transfect Ad-SOCS2. HG group, HG-Ad-null group, HG-Ad-SOCS2 group, CG group, CG-Ad-null group, and CG-Ad-SOCS2 group were created. The expression of inflammatory cytokines (MCP-1, TNF-α and IL-6) in kidney tissue of rats, fibrosis related protein (FN, Collagen IV and TGF-ß) in kidney tissue and cells of rats, and JAK/STAT signaling pathway related proteins (p-JAK2 and p-STAT3) were tested by western blot. ELISA was used to test the expression of inflammatory cytokines (TNF-α and IL-6) in cells. RESULTS: The expression of inflammatory cytokines in DN rats (MCP-1, TNF-α and IL-6) and cell (TNF-α and IL-6) were increased (P < 0.01) significantly. However, SOCS2 could decrease the overexpression of mediated inflammatory cytokines in DN animal models and cell models (P < 0.01). The expression of fibrosis related protein in DN rats and cells increased while SOCS2 decreased the overexpression of mediated fibrosis related protein in DN model rats and cells (P < 0.01). The expression of JAK/STAT pathway related protein in both DN rats and cells increased and the JAK/STAT signaling pathway was activated. Yet, SOCS2 obviously suppressed the expression of the JAK/STAT signaling pathway as well as the related proteins (p-JAK2 and p-STAT3) in both DN rats and cells. CONCLUSIONS: The overexpression of SOCS2 can decrease the expression of inflammatory cytokines and fibrosis related proteins in DN rats and cells, and meanwhile suppress the activation of JAK/STAT signaling pathway mediated by DN.

Comparison of two fluid solutions for resuscitation in a rabbit model of crush syndrome.

BACKGROUND: Crush syndrome is a common injury, the main characteristics of which include acute kidney injury. However, there is still lack of reliable animal model of crush syndrome, and it also remains controversial as to which type of fluid should be chosen as a more appropriate treatment option for prevention and treatment of acute kidney injury. METHODS: The rabbits were crushed at the lower limbs for 6 h with 36 times the body weight, which means the pressure of each leg was also 36 times the body weight. Fluid resuscitation was performed from 1 h prior to the end of the crush treatment until 24 h after the reperfusion. Tissue, blood and urine samples were collected at predetermined time points before and after reperfusion. Twelve rabbits in each group were taken for survival observation for 72 h. RESULTS: The model group showed elevated serum creatine kinase, aspartate aminotransferase, alanine aminotransferase, and K(+) level, reduced serum Ca(2+) level and Na(+) level, and increased serum creatinine and blood urea nitrogen levels, neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 (p < 0.05). The 0.9 % normal saline (SAL) group and SAL plus 6 % hydroxyethyl starch 130/0.4 SAL/HES group showed reduced serum creatinine and blood urea nitrogen levels (p < 0.05). The SAL/HES group also showed reduced serum IL-6 and IL-10 levels (p < 0.05). The 72 h survival rate of the SAL/HES group was higher than that of the model group (p < 0.05). CONCLUSION: The rabbit model of crush syndrome showed clinical features consistent with those of crush syndrome. There was no significant difference in the ability of preventing AKI after a crush injury between the two fluid solutions, while SAL/HES can improve the survival rate.

[Removal of estrogens in laccase catalyzed oxidative processes].

The removal of 5 estrogens (bisphenol A, estradiol, ethinylestradiol, estrone and octylphenol) in laccase catalyzed oxidative processes was studied. The effects of pH and NOM on the removal of EDCs were discussed in detail, as well as the kinetics of EE2 removal and the reaction products. The results indicated that laccase was capable of removing estrogens efficiently. The optimal pH was between 4 and 6. NOM significantly inhibited the removal of estrogens at the initial stage of the reaction. However, the adverse effect of NOM was not obvious after 24 h treatment. The removal of EE2 obeyed the second-order kinetics. The activity of laccase remained stable during the reactions and the stability was higher than that of peroxidase. MS analysis demonstrated that the EE2 dimer formed through radical coupling mechanism was the main reaction product.

[Chlorination of ethynyl estradiol: a kinetic and mechanistic study].

The objective of this research is to explore the fundamentals of reactions between chlorine and ethynyl estradiol (EE2), which is expected to occur during the drinking water treatment. The first step of EE2 chlorination was shown to follow the second-order kinetics with the first order to concentrations of both target compound and chlorine, respectively. Apparent rate constants of EE2 chlorination exhibit the pH-dependent profile which indicates that the phenolic ring is the preferred site of attack by Cl. The transformation of EE2 is governed by 3 elementary reactions between different species of EE2 and HClO. The deprotonated EE2 anion is significantly more reactive than its neutral conjugate. HPLC/MS analysis revealed that several Cl atoms can be incorporated into this site via complex multi-step pathways, resulting in the formation of mono and di-chlorine substituted EE2. The incorporation of the third Cl is accompanied by immediate broken down of the ring via hydrolysis. The results of this study are helpful to fully understand the behavior of EE2 in chlorinated drinking water disinfection, provide the basis for evaluating the potential exposure of this contaminant to human. The data of this work also give insights to the formation of chlorinated drinking water disinfection by-products (DBPs).

[Effects of multiple environmental factors on triflulsulfuron-methyl degradation in soils].

Triflulsulfuron-methyl, a widely used sulfonylurea herbicide, has done harm to the soil and crop. Its environment fate was affected by many factors such as physicochemical or biological factors. In order to understand the effects of different environmental factors on the degradation of triflulsulfuron-methyl in soil, simulated indoor incubation experiments were carried out to explore the effects of soil microbe, soil type, dissolved organic matter (DOM), temperature, and soil moisture on triflulsulfuron-methyl degradation in soils. The results showed that different environmental factors such as temperature, soil moisture, soil microorganisms and soil type influenced triflulsulfuron-methyl degradation in different degrees. The increased soil microbial biomass, soil organic matters and DOM were beneficial to the soil degradation of triflulsulfuron-methyl, meanwhile, the decrease in soil pH could accelerate its degradation in soils. The results showed that soil microorganisms were the main factor effecting the degradation of triflulsulfuron-methyl in soil. Our results provided initial data for the conclusion that a set of biological and physiochemical factors coordinately regulate the decay of triflulsulfuron-methyl in soils.