Laccase-induced decontamination and humification mechanisms of estrogen in water-crop matrices.

Enzymatic humification plays a crucial biogeochemical role in eliminating steroidal estrogens and expanding organic carbon stocks. Estrogenic contaminants in agroecosystems can be taken up and acropetally translocated by crops, but the roles of laccase-triggered rhizospheric humification (L-TRH) in pollutant dissipation and plant uptake remain poorly understood. In this study, the laccase-induced decontamination and humification mechanisms of 17ß-estradiol (E2) in water-crop media were investigated by performing greenhouse pot experiments with maize seedlings (Zea mays L.). The results demonstrated that L-TRH effectively dissipated E2 in the rhizosphere solution and achieved the kinetic constants of E2 dissipation at 10 and 50 µM by 8.05 and 2.75 times as much as the treatments without laccase addition, respectively. The copolymerization of E2 and root exudates (i.e. phenols and amino acids) consolidated by L-TRH produced a larger amount of humified precipitates with the richly functional carbon architectures. The growth parameters and photosynthetic pigment levels of maize seedlings were greatly impeded after a 120-h exposure to 50 µM E2, but L-TRH motivated the detoxication process and thus mitigated the phytotoxicity and bioavailability of E2. The tested E2 contents in the maize tissues initially increased sharply with the cultivation time but decreased steadily. Compared with the treatment without laccase addition, the uptake and accumulation of E2 in the maize tissues were obviously diminished by L-TRH. E2 oligomers such as dimer, trimer, and tetramer recognized in the rhizosphere solution were also detected in the root tissues but not in the shoots, demonstrating that the acropetal translocation of E2 oligomers was interrupted. These results highlight a promising strategy for decontaminating estrogenic pollutants, boosting rhizospheric humification, and realizing low-carbon emissions, which would be beneficial for agroenvironmental bioremediation and sustainability.

Biochar decreased the bioavailability of Zn to rice and wheat grains: Insights from microscopic to macroscopic scales.

Zn deficiency is a critical problem for many crops and human populations worldwide. Soil biochar amendment has recently been promoted as a sustainable agricultural practice. However, its effect on the bioavailability of micronutrients (especially Zn) to crops has not been fully addressed. This study investigated the impact of long-term biochar application in soils on Zn bioavailability to rice and wheat, using field experiments, and batch sorption/desorption experiments, in combination with extended X-ray absorption fine structure spectroscopy (EXAFS). In field soils biochar amendment increased total Zn content, but significantly decreased CaCl2-extractable Zn concentrations. Intriguingly, the uptake of Zn to wheat and rice grains was decreased. At high biochar application rates of 124 and 270t/ha the Zn concentrations in wheat grains (36.6 and 37.5mg/kg) reached a deficient level, lower than the recommended concentration of 45mg/kg. The batch experiments showed that biochar application at a cumulative rate of 10.5, 15.8, 31.5, 124, and 270t/ha significantly increased soil pH and soil organic matter (SOM) content, resulting in greater sorption and lower desorption of Zn. The EXAFS results demonstrated that the main forms of sorbed Zn were outer-sphere Zn complexes, Zn-illite, Zn-kaolinite and Zn-OM. The proportion of Zn-OM increased with increasing biochar application rates, suggesting that higher SOM might be more effective in immobilizing Zn and thus decreasing the Zn bioavailability. These results on the microscopic and macroscopic scales improved our understanding of the Zn bioavailability to crops, and raised potential concerns on the Zn deficiency in agricultural soils with long-term biochar application.

[Intervention Effect of Modified Dachengqi Decoction on Intestinal Mucosal Barrier of Severe Acute Pancreatitis Model Rats].

OBJECTIVE: To study the effect of Modified Dachengqi Decoction (MDD) as whole course therapy on mediators of inflammation in severe acute pancreatitis (SAP) model rats, and to compare interventional advantages over intestinal mucosal barrier (IMB) of SAP rats between whole course therapy of MDD and early stage therapy of MDD. METHODS: Totally 190 SD rats were divided into five groups according to random digit table, i.e., the sham-operation group, the model group, the octreotide (OT) group, the early stage MDD treatment group, the whole course MDD treatment group, 38 in each group. SAP models were established with retrograde injection of 5% sodium taurocholate into the pancreaticobiliary duct. Three hours after modeling normal saline (NS) was administered to rats in the sham-operation group and the model group by gastrogavage, once per 12 h.1.35 µg/100 g OT was subcutaneously injected to rats in the OT group, once every 8 h. 0.4 mL/100 g MDD was administered to rats in the early stage MDD treatment group, and 6 h later changed to NS (once per 12 h).0.4 mL/100 g MDD was administered to rats in the whole course MDD treatment group, once every 12 h. The accumulative survival rate and morphological manifestations of pancreas and small intestine were observed under microscope 48 h after modeling. Pathologic scores of the pancreas and small intestine were conducted at 4, 6, 24, and 48 h after modeling. Contents of serum amylase (AMY), alanine transaminase (ALT), and TNF-α were also detected. The expression of high mobility group box protein 1 (HMGB1) in the small intestine tissue was also detected by Western blot. The positive rate of bacterial translocation in mesenteric lymph nodes (MLNs) was observed within 48 h. Correlations between serum TNF-α or HMGB1 in small intestinal tissue and pathological scores of the pancreas or the small intestine were analyzed. RESULTS: The accumulative survival rate was 100. 0% in the sham-operation group, 79. 2% in the whole course MDD treatment group, 70. 8% in the OT group, 45. 8% in the early stage MDD treatment group, and 37.5% in the model group. At 6 h after modeling, pathological scores decreased more in the whole course MDD treatment group, the early stage MDD treatment group, the OT group than in the model group (P < 0.05). At 24 and 48 h after modeling, pathological scores of the pancreas and the small intestine decreased more in the whole course MDD treatment group and the OT group than in the early stage MDD treatment group (P <0. 05). At 6, 24, and 48 h after modeling, serum contents of AMY and ALT both decreased more in the whole course MDD treatment group, the early stage MDD treatment group, the OT group than in the model group (P < 0.05). At 48 h after modeling serum contents of AMY and ALT both decreased more in the whole course MDD treatment group and the OT group than in the early stage MDD treatment group (P < 0.05). At 6 h after modeling serum TNF-α levels decreased more in the whole course MDD treatment group, the early stage MDD treatment group, the OT group than in the model group (P < 0.05). At 6, 24, and 48 h after modeling the level of HMGB1 in the small intestinal tissue decreased more in the whole course MDD treatment group, the early stage MDD treatment group, the OT group than in the model group (P < 0.05). Of them, HMGB1 levels at 24 and 48 h were lower in the whole course MDD treatment group and the OT group than in the early stage MDD treatment group (P < 0.05). The number of MLNs bacterial translocation at 48 h after modeling was lower in the whole course MDD treatment group and the OT group than in the early stage MDD treatment group and the model group (P < 0.05). Serum TNF-α contents within 6 h were positively correlated with pathological scores of pancreas (r = 0.579, P < 0.01). ROC curve showed that serum TNF-α contents could predict the severity of SAP (ROC = 0.990, 95% Cl: 0.971 to 1.000). HMGB1 in the small intestine was positively correlated with pathological scores of the small intestine (r = 0.620, P < 0.01). CONCLUSIONS: Early stage use of MDD could effectively reduce the release of TNF-α, while whole course use of MDD could effectively inhibit the expression of HMGB1. The latter could preferably attenuate injuries of the pancreas and the small intestine, lower MLNs bacterial translocation, and elevate the survival rate.

[Study on effects of Tripterygium wilfordii polycoride in resisting macrophage inflammation and regulating inflammation via TLR4/NF-κB].

To investigate the effect of Tripterygium wilfordii polycoride (TWP) on LPS-induced macrophage inflammatory response, particularly the inhibitory effect on inflammatory factors TNF-α and IL-1ß and the regulatory effect on inflammation via TLR4/NF-κB. The MTT method was adopted to test the effects of tested drugs, TWP, dexamethasone (DXM) and azathioprine (AZA) on cell growth to define the appropriate concentration. LPS was used to induce the inflammatory reaction in mouse RAW264. 7 cell lines. The Elisa kit was adopted to test the release level of TNF-α and IL-1ß. The Western blotting was applied to test the protein expressions of TNF-α and IL-1ß. The RT-PCR was adopted to test the expressions of TLR4 and NF-κB. According to the results, TWP could inhibit the release of macrophage inflammatory factors TNF-α and IL-1ß in a dose dependent manner. All of TWP groups showed a weaker efficacy than that of the DXM group. But the TWP high dose group revealed a better effect on TNF-α and equal effect on IL-1ß compared with the AZA group. TWP show an equal or better effect in down-regulating TLR4 and NF-κB p65 expressions in a dose dependent manner than DXM and AZA. In conclusion, TWP could inhibit TLR4 and NF-κB p65, which may be related to the down-regulation of TLR4 and NF-κB p65 receptor expressions.

Superoxide mediated production of hydroxyl radicals by magnetite nanoparticles: demonstration in the degradation of 2-chlorobiphenyl.

Increasing attention has been paid to magnetite nanoparticles (MNPs) due to their highly reductive reactivity toward environmental contaminants. However, there is little information related to the generation of reactive oxygen species (ROS) by MNPs, which in fact plays a vital role for the transformation of contaminants. In this paper, the degradation of 2-chlorobiphenyl (2-CB) by MNPs was investigated. The role of ROS generated by MNPs in this process was elucidated. The results demonstrated that hydroxyl radicals (OH) generated by MNPs at low pH could efficiently degrade 2-CB. The mechanism of the formation of OH by MNPs was divided into two steps: (i) the superoxide radical anion (O2(-)) mediated production of hydrogen peroxide (H2O2), and (ii) the reaction of formed H2O2 with Fe(II) dissolved from MNPs to produce OH through Fenton reaction. Comparison of the degradation products of 2-CB by MNPs with MNPs/ethanol and Fenton reagents further supported the involvement of OH in the degradation of 2-CB. The degradation efficiency of 2-CB by MNPs under acidic conditions was higher than that in alkaline solution. These findings provide a new insight into the understanding of reactivity of MNPs for the transformation of 2-CB and possibly other relevant environmental contaminants.

Reducing the bioavailability of PCBs in soil to plant by biochars assessed with triolein-embedded cellulose acetate membrane technique.

Coupling with triolein-embedded cellulose acetate membrane (TECAM) technique, hydroxypropyl ß-cyclodextrins (HPCD) extraction method, and the greenhouse pot experiments, the influences of biochars on polychlorinated biphenyls (PCBs) bioavailability in soil to plant (Brassica chinensis L. and Daucus carota) were investigated. Addition of 2% biochars to soils significantly reduced the uptake of PCBs in plant, especially for di-, tri- and tetra-chlorobiphenyls. PCBs concentrations in the roots of B. chinensis and D. carota were reduced for 61.5-93.7%, and 12.7-62.4%, respectively in the presence of biochars. The kinetic study showed that in the soils amended with/without biochars, PCBs concentrations accumulated in TECAM, as well as in the HPCD extraction solution, followed significant linear relationships with those in plant roots. Application of biochars to soil is a potentially promising method to reduce PCBs bioavailability whereas TECAM technique can be a useful tool to predict the bioavailability of PCBs in soil.

Transformation of polychlorinated biphenyls by persulfate at ambient temperature.

Increasing attention has been paid to persulfate due to its high efficiency in degrading organic pollutants. This paper investigated the transformation of a selected polychlorinated biphenyl (PCB) by sodium persulfate without activators at near ambient temperature (10-40°C). The results showed that 2,4,4'-CB was completely decomposed by persulfate at 30°C in 8 h. The products were identified by gas chromatography-mass spectrometry (GC-MS), and transformation pathways could be divided into two steps as dechlorination and hydroxylation. Electron paramagnetic resonance (EPR) technique was used to identify the generated radical species at different pH values at ambient temperature. The results showed that sulfate radicals (SO(4)(•-)) were predominant under acidic condition and hydroxyl radicals ((•)OH) were predominant under basic condition. This behavior was also confirmed by the quenching studies and kinetic model. Decreasing the solution pH resulted in increasing the degradation efficiency of 2,4,4'-CB. Moreover, the degradation of other PCBs such as 2-CB, 4-CB, 2,4-CB, 2,4'-CB, and 2,4,6-CB with persulfate was examined. The findings of this study can provide guidance in the remediation of PCBs contaminated soil and water with persulfate.

Sulfate radical-based degradation of polychlorinated biphenyls: effects of chloride ion and reaction kinetics.

Advanced oxidation processes (AOPs) based on sulfate radical (SO(4)(·-)) have been recently used for soil and groundwater remediation. The presence of chloride ion in natural or wastewater decreases the reactivity of sulfate radical system, but explanations for this behavior were inconsistent, and the mechanisms are poorly understood. Therefore, in this paper we investigated the effect of chloride ion on the degradation of 2,4,4'-CB (PCB28) and biphenyl (BP) by persulfate, based on the produced SO(4)(·-). The results showed that the presence of chloride ion greatly inhibited the transformation of PCB28 and BP. Transformation intermediates of BP were monitored, suggesting that the chloride ion can react with SO(4)(·-) to produce chlorine radical, which reacts with BP to generate chlorinated compounds. To better understand the underlying mechanisms of these processes, a kinetic model was developed for predicting the effect of chloride ion on the types of radical species and their distributions. The results showed that chloride ion could influence the selectivity of radical species and their distribution, and increase the concentration of the sum of radical species. In addition, the second-order rate constants of sulfate radical with PCBs were determined, and quantum-chemical descriptors were introduced to predict the rate constants of other PCBs based on our experimental data.

[Dechlorination degradation of 2,4-D by nanoscale Fe3O4].

Reductive transformation of 2,4-Dichlorophenoxyacetic acid (2,4-D) by nanoscale Fe3O4 was studied, and the effects of 2,4-D initial concentration, the dosage of nanoscale Fe3O4, pH and temperature on degradation rate of 2,4-D were investigated. The results showed that 48% 2,4-D with initial concentration of 10 mg/L was transformed within 48 h in the presence of 300 mg/L nanoscale Fe3O4. The degradation of 2,4-D was a reductive dechlorination process, and the concentration of chloride ion increased sharply with the degration of the 2,4-D. Disappearance of parent species and formation of reaction intermediates and products were analyzed by LC/MS. The transformation of 2,4-D followed a primary pathway of its complete reduction to phenol and a secondary pathway of sequential reductive hydrogenolysis to 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) or 2-chlorophenol (2-CP) and phenol. The degradation equations of 2,4-D by nanoscale Fe3O4 conformed to pseudo-first-order kinetics, and the reaction rate constant (K) of 4-CP, 2,4-DCP and phenol were 0.0043 h(-1), 0.0026 h(-1) and 0.0032 h(-1), respectively. The degradation rate increased with an increase in initial concentration of 2,4-D from 0 mg/L to 10 mg/L, and increasing the dosage of nanoscale Fe3O4 from 0 mg/L to 300 mg/L. The pH of reaction solution significantly influenced reductive degradation of 2,4-D, and the optimum pH value was 3.0. Besides, high temperature could improve dechlorination rate of 2,4-D.

Inhibiting the inflammatory response in joint sepsis.

PURPOSE: We created a rabbit model of infectious arthritis to test the effects of WRC-0470 (2-cyclohexylmethylidenehydarazinoadenosine), an adenosine analogue, and rolipram, a type IV phosphodiesterase inhibitor, on intra-articular white blood cell recruitment. Type of Study: Randomized trial involving mature rabbits. METHODS: Intra-articular injections ranging from 0 to 2,000 ng of Escherichia coli lipopolysaccharide (LPS) were tested as the infectious stimulus. The optimal LPS amount was determined based on synovial fluid analysis for white blood cell counts. A separate cohort of rabbits then received various intravenous concentrations of either rolipram, WRC-0470, or a combination of the 2 medications. Synovial fluid aspirations after a 6-hour incubation were analyzed for white blood cell counts. RESULTS: Intra-articular injections of 200 ng of LPS reproducibly generated an inflammatory response of 4,000 cells/mL of synovial fluid, establishing the use of this dose of LPS for our septic arthritis model. Following infusions of 10 µg/kg/min, the average white blood cell count dropped to 800 cells/mL for WRC-0470 (P <.01) and 1,225 cells/mL for rolipram (P <.05). A synergistic effect was seen with the combination of both medications at just 1.0 µg/kg/min, with a mean white blood cell count of 1,090 cells/mL (P <.01). CONCLUSIONS: Septic arthritis is a common clinical entity that frequently results in major long-term morbidity. Although bacteria can directly damage the articular surface, the cytokine-mediated immune response to the infection can exacerbate the insult by promoting the release of proteolytic enzymes by white blood cells. Currently, no established intervention exists that will decrease the inflammatory response to infectious challenges. Our study shows that WRC-0470 and rolipram effectively reduce the intra-articular recruitment of white blood cells in a septic arthritis model. Future investigations of these drugs will determine their ultimate degree of efficacy at limiting the joint destruction associated with septic arthritis.