Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO42- mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO42- ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate.

[Effects of Goethite, Magnetite and Gypsum on the Anaerobic Degradation of 2,4-Dichlorophenol].

2,4-dichlorophenol(2,4-DCP), a highly toxic and refractory organic compound, was commonly used in pesticide production and thus widely distributed in water and soil. Goethite, magnetite and gypsum were added into the anaerobic system which simulated the natural anaerobic process to evaluate their effects on the anaerobic degradation of 2,4-DCP. It indicated that goethite, magnetite and gypsum had no appreciable adsorption ability toward 2,4-DCP under anaerobic condition. Mass balance analysis showed that only the transformation of 2,4-DCP to 4-chlorophenol(4-CP) occurred in all experimental groups. The addition of sodium acetate doubled the reductive dechlorination rate of 2,4-DCP in comparison with the groups without exogenous carbon source. The reductive dechlorination rate of 2,4-DCP was enhanced by the addition of goethite and magnetite, which was caused by the improved metabolic activity of dechlorination bacteria that played an important role in the anaerobic degradation of 2,4-DCP. Gypsum greatly inhibited or even stopped the degradation process of 2,4-DCP through restraining the growth and activity of dechlorination bacteria. This study will shed light on the migration and degradation of refractory chlorinated organic contaminants in anaerobic sedimentary environment, and the treatment of such matters in environmental technology.

Carvacrol attenuates traumatic neuronal injury through store-operated Ca(2+) entry-independent regulation of intracellular Ca(2+) homeostasis.

Searching for effective pharmacological agents for traumatic brain injury (TBI) treatment has largely been unsuccessful. The transient receptor potential melastatin 7 (TRPM7), a TRP channel that is essential for embryonic development, has been shown to mediate ischemic neuronal injury in vivo and in vitro, but global deletion of TRPM7 in mice is lethal. Here, carvacrol was used to investigate the protective effect of TRPM7 inhibition in an in vitro traumatic neuronal injury model. Carvacrol (0.5 and 1 mM) reduced lactate dehydrogenase (LDH) release, apoptosis and caspase-3 activation after traumatic injury in cortical neurons. These neuroprotective effects were accompanied by alleviated cytoplasmic calcium levels as measured by calcium imaging. In contrast, the thapsigargin (TG) induced store-operated calcium entry (SOCE) and the expression of SOCE related proteins in neurons were not altered by carvacrol treatment. The involvement of TRPM7 sensitive calcium influx in our in vitro model was confirmed by the results that bradykinin induced calcium influx was prevented by carvacrol in neurons. Furthermore, carvacrol significantly inhibited the induction of neuronal nitric oxide synthase (nNOS) after traumatic injury, and treatment with carvacrol and the nNOS inhibitor NLPA together had no extra effect on calcium concentration and neuronal injury. Thus, inhibition of TRPM7 function by carvacrol protects against traumatic neuronal injury, and might be a potential drug development strategy for the treatment of TBI.

NBM-T-BMX-OS01, an Osthole Derivative, Sensitizes Human Lung Cancer A549 Cells to Cisplatin through AMPK-Dependent Inhibition of ERK and Akt Pathway.

BACKGROUND: Drug combination therapies using cisplatin and natural products are common practice in the treatment of human lung cancer. Osthole is a natural compound extracted from a number of medicinal plants and has been shown to exert strong anticancer activities with low toxicity. METHODS: In the present study, NBM-T-BMX-OS01 (BMX), derived from the semi-synthesis of osthole, was evaluated in cisplatin treated A549 cells to investigate its effect on cisplatin resistance in human lung cancer. The anticancer effect of BMX were measured by cell viablity' colony formation' TUNEL staining' flow cytometry and cell cycle assay. The fluorescence staining was performed to detect intracellular and mitochondrial reactive oxygen species (ROS) generation. Western blot analysis, antagonists pretreatment and small interfering RNA (siRNA) transfection were used to determine the potential mechanism. RESULTS: It was found that, in comparison with single cisplatin treatment, the combination of BMX and cisplatin resulted in greater efficacy in inhibition of proliferation and colony formation, apoptosis induction and cell cycle arrest. The results of fluorescence staining showed that the combination effect of BMX and cisplatin was due to oxidative stress induced by mitochondrial ROS generation. In addition, BMX significantly attenuated the phosphorylation of ERK and Akt, two important pro-survival kinases. In contrast, BMX inhibited the activation of AMPK, and knockdown of AMPK using specific siRNA partially reversed BMX-induced inhibition of ERK and Akt, as well as its synthetic effects on cisplatin induced anticancer activity in A549 cells. CONCLUSION: Taken together, this study provides that BMX might modulate cisplatin resistance through AMPK-ERK and AMPK-Akt pathways. These results also support the role of BMX as a potential drug candidate for use in combination with cisplatin in the treatment of human lung cancer.

Competitive adsorption of heavy metal by extracellular polymeric substances (EPS) extracted from sulfate reducing bacteria.

Competitive adsorption of heavy metals by extracellular polymeric substances (EPS) extracted from Desulfovibrio desulfuricans was investigated. Chemical analysis showed that different EPS compositions had different capacities for the adsorption of heavy metals which was investigated using Cu(2+) and Zn(2+). Batch adsorption tests indicated that EPS had a higher combined ability with Zn(2+) than Cu(2+). This was confirmed and explained by Fourier transform infrared (FTIR) and excitation-emission matrix (EEM) spectroscopy analysis. FTIR analysis showed that both polysaccharides and protein combined with Zn(2+) while only protein combined with Cu(2+). EEM spectra further revealed that tryptophan-like substances were the main compositions reacted with the heavy metals. Moreover, Zn(2+) had a higher fluorescence quenching ability than Cu(2+).

Synthetic effect between iron oxide and sulfate mineral on the anaerobic transformation of organic substance.

Synthetic effect between sulfate minerals (gypsum) and iron oxide (hematite) on the anaerobic transformation of organic substance was investigated in the current study. The results showed that gypsum was completely decomposed while hematite was partially reduced. The mineral phase analysis results showed that FeS and CaCO3 was the major mineralization product. Methane generation process was inhibited and inorganic carbon contents in the precipitates were enhanced compared to the control without hematite and gypsum. The inorganic carbon content increased with the increasing of hematite dosages. Co-addition of sulfate minerals and iron oxide would have a potential application prospect in the carbon sequestration area and reduction of the greenhouse gas release. The results would also reveal the role of inorganic mineral in the global carbon cycle.

Allicin protects rat cortical neurons against mechanical trauma injury by regulating nitric oxide synthase pathways.

Allicin, a small molecule that is responsible for the typical smell and most of the functions of garlic, possesses a broad spectrum of pharmacological activities and is considered to have therapeutic potential in many pathologic conditions. In the present study, we investigated the potential protective effect of allicin in an in vitro model of traumatic brain injury (TBI) using primary cultured rat cortical neurons. We found that allicin treatment significantly reduced mechanical trauma-induced lactate dehydrogenase (LDH) release and inhibited apoptotic neuronal death in a dose-dependent manner. These protective effects were observed even if allicin treatment was delayed to 2h after injury. Allicin significantly decreased the expression of inducible nitric oxide synthase (iNOS) and increased the phosphorylation of endothelial NOS (eNOS) but had no effect on neuronal NOS (nNOS) expression. Allicin-induced protection in cortical neurons was augmented by iNOS and nNOS antagonists and was partly reversed by blocking eNOS phosphorylation. In addition, allicin treatment inhibited the TBI-induced activation of ERK and further enhanced the phosphorylation of Akt in TBI-injured neurons. The Akt inhibitor LY294002 attenuated the allicin-induced increase in eNOS expression and phosphorylation, whereas the ERK inhibitor PD98059 had opposite effects on the expression of iNOS and eNOS. Pretreatment with LY294002 or PD98059 partly prevented or further enhanced allicin-induced neuroprotection, respectively. Collectively, these data demonstrate that allicin treatment may be an effective therapeutic strategy for traumatic neuronal injury and that the potential underlying mechanism involves Akt- and ERK-mediated regulation of NOS pathways.

[Effect of the interaction of microorganisms and iron oxides on arsenic releasing into groundwater in Chinese Loess].

A large part of groundwater in the Chinese Loess Plateau area is characterized by high arsenic concentration. Anaerobic bacteria have been considered to play key roles in promoting arsenic releasing from loess to groundwater. However, this hypothesis remains unconfirmed. Based on modeling experiments, this study investigated the speciation of arsenic in loess, and then determined the release rates and quantities of arsenic with the mediation of anaerobic bacteria. The results showed that arsenic contents in loess were between 23 mg.kg-1 and 30 mg.kg-1. No obvious arsenic content difference among loess samples was observed. The ratios for specific adsorbed, iron oxides co-precipitated and silicate co-precipitated arsenic were 37.76% , 36. 15% and 25. 69% , respectively. Indigenous microorganisms, dissimilatory iron reducing bacteria (DIRB) and sulfate reducing bacteria (SRB) could all promote the release of arsenic from loess. Organic matters highly affected the release rates. More than 100 mg.L-1 sodium lactate was required for all bacterial experiments to facilitate obvious arsenic release. Considering the redox condition in loess, the contribution of SRB to arsenic release in loess area was less feasible than that of DIRB and indigenous microorganisms.

Osthole attenuates spinal cord ischemia-reperfusion injury through mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction in rats.

BACKGROUND: Osthole, the main bioactive compounds isolated from the traditional Chinese medical herb broad Cnidium monnieri (L.) cusson, has been shown to exert spectrum of pharmacologic activities. The aim of this study was to investigate the potential neuroprotective effects of osthole against spinal cord ischemia-reperfusion injury in rats. MATERIALS AND METHODS: Osthole was administrated at the concentration of 0.1, 1, 10, 50, or 200 mg/kg (intraperitoneally) 1 h before spinal cord ischemia. The effects on spinal cord injury were measured by spinal cord water content, infarct volume, hematoxylin and eosin staining, and neurologic assessment. Mitochondria were purified from injured spinal cord tissue to determine mitochondrial function. RESULTS: We found that treatment with osthole (10 and 50 mg/kg) significantly decreased spinal cord water content and infarct volume, preserved normal motor neurons, and improved neurologic functions. These protective effects can be also observed even if the treatment was delayed to 4 h after reperfusion. Osthole treatment preserved mitochondrial membrane potential level, reduced reactive oxygen species production, increased adenosine triphosphate generation, and inhibited cytochrome c release in mitochondrial samples. Moreover, osthole increased mitochondria respiratory chain complex activities in spinal cord tissue, with no effect on mitochondrial DNA content and the expression of mitochondrial-specific transcription factors. CONCLUSIONS: All these findings demonstrate the neuroprotective effect of osthole in spinal cord ischemia-reperfusion injury model and suggest that oshtole-induced neuroprotection was mediated by mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction.

[Effect of natural and hydrothermal synthetic goethite on the release of methane in the anaerobic decomposition process of organic matter].

The effects of natural goethite (NGt) and synthetic goethite (SGt) on the release of methane in the anaerobic biochemical system consisted of dissimilatory iron-reducing bacteria (DIRB) and methane-producing bacteria (MPB) were investigated through batch tests with sodium acetate as the carbon source. To explore the effects and mechanisms of both mineral materials on the release of methane in the anaerobic decomposition process of organic matter in the presence of DIRB, the main gas components and total organic carbon (TOC) , total inorganic carbon (TIC), and Fe2+ in the aqueous phase of the experimental process were determined and XRD analyses were conducted for the solid-phase product. Moreover, the minerals were analyzed by specific surface area (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF). Modified Gompertz equation was used to fit the cumulative methane and carbon dioxide. Results showed that the maximum cumulative production of methane was brought forward by 60-78 days by the addition of goethite and CO2 was effectively reduced by 30% - 67% compared with the control samples. SGt was more effective than NGt in promoting the release of CH4 and reducing the CO, emission. Furthermore, the analysis of the solid product showed that the addition of goethite can fix part of CO2 by the formation of siderite.

[Experimental study on acid mine drainage treatment using mine tailings of Xiangsi Valley, Tongling, China].

Mine tailings in Xiangsi Valley, Tongling, China, is a typical skarn-type tailing with high contents of carbonates. This study designed dynamic leaching experiments to investigate the efficiency of this tailing under the acid mine drainage treatment. During 80 d trial period, the physical and chemical properties of influents were fixed and the effluents were monitored. After the trial, the speciation of Fe, Cu and Zn in solid was analyzed. The results showed that during the trial period, pH value maintained above 7.5. Moreover, the concentrations of Cu, Zn, Fe ions in effluents kept below 0.1, 0.4 and 1 mg x L(-1), respectively. In addition, the permeability coefficient of experimental column kept decreasing during the experimental period (from 0.23 cm x s(-1) to 0.10 cm x s(-1)). Five-step sequential extraction method was employed to study the distribution of elements at different depths. The results showed that Cu2+, Zn2+ were removed mainly through sorption and precipitation. This study indicates that Tongling skarn mine tailings have strong acid neutralization as well as heavy metal binding capacities. Therefore, the authors suggest that this mine tailing, which used to be waste, has a potential in AMD control and treatment.

[Effect of Zn(II) on microbial activity in anaerobic acid mine drainage treatment system with biomass as carbon source].

In this study, with rape straw as carbon source, anaerobic batch experiments were executed to investigate the effect of Zn (II) on the activity of sulphate reducing bacteria (SRB) in the microbial treatment of simulative acid mine drainage (AMD). The results showed that during the 60 experimental days, when initial Zn2+ concentrations were in the range of 73.7 to 196.8 mg x L(-1), SRB had high culturalbility. At the end of these experiments, pH values rose from initial 5.0 to neutral, about 96% of sulphate was reduced and the concentrations of Zn2+ reduced to 0.05 mg x L(-1). The results of Tessier sequential extraction, field emission scanning electron microscope (FE-SEM) and X-ray diffraction(XRD) showed that Zn was found to be fixed through forming organic and sulphide (mainly sphalerite) compounds. For the experiment with high Zn2+ concentration (262.97 mg x L(-1)), at the end of experiments, pH values dropped from initial 5.0 to 4.0, only 27% of sulphate was only reduced and the concentrations of Zn2+ kept in high range (25 mg x L(-1)), the activity of SRB significantly inhibited. This study indicated that: (1) Rape straw can be used as slow-release carbon source for long-term anaerobic AMD treatment; (2) Rape straw can decrease the toxicity of Zn2+ to SRB through adsorption; (3) In anaerobic AMD treatment system, Zn can be fixed by sulphide minerals with mediation of SRB.

[Formation and environmental implications of iron-enriched precipitates derived from natural neutralization of acid mine drainage].

Acid mine drainage (AMD) and its natural neutralizing products in Wangjiatan iron mine were collected and analyzed by using spectroscopic and electron microanalytic methods. The results show that after natural neutralization of AMD by surface water of the stream, acidity and electric conductivity of AMD are both decreased. While for dissolved elements, no other element is obviously decreased except for Fe3+, SO4(2-), and Ca2+. For precipitates formed by natural neutralization, Fe is enriched and ferrihydrite is the main iron mineral, with little amount of goethite and fibroferrite contained in downstream precipitates. To ferrihydrite, 2-line and 6-line ferrihydrite are the main mineral type in upstream and downstream precipitates, respectively. Furthermore, for all precipitates, two layers are observed. In outer layer 2-line ferrihydrite is the main mineral, while in inner layer 6-line ferrihydrite and goethite are the main minerals. Ferrihydrite dominated precipitates are favorable in immobilizing toxic and hazardous elements. Furthermore, it is demonstrated that pH and the concentration of SO4(2-) are decisive factors for ferrihydrite formation. The ferrihydrite translocation and its attenuation for toxic elements are, to a great extent, affected by hydrodynamics in neutralization zone.

Optimized enzymatic preparation of 1-deoxy-d-xylulose 5-phosphate.

The preparation of 1-deoxy-d-xylulose 5-phosphate, the key intermediate of MEP biosynthetic pathway for terpenoids by using recombinant 1-deoxy-d-xylulose 5-phosphate synthase of Rhodobacter capsulatus was optimized. The simple one-pot synthesis coupling with a newly established ion-exchange purification process affords the target compound with more than 80% yield and high purity (>95%). The procedure can also be employed to synthesize isotope labeled 1-deoxy-d-xylulose 5-phosphate by using isotope labeled starting materials.