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Find video protocols related to scientific articles indexed in Pubmed.
Differentiating surface and bulk interactions in nanoplasmonic interferometric sensor arrays.
Nanoscale
PUBLISHED: 11-20-2014
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Detecting specific target analytes and differentiating them from interfering background effects is a crucial but challenging task in complex multi-component solutions commonly encountered in environmental, chemical, biological, and medical sensing applications. Here we present a simple nanoplasmonic interferometric sensor platform that can differentiate the adsorption of a thin protein layer on the sensor surface (surface effects) from bulk refractive index changes (interfering background effects) at a single sensing spot, exploiting the different penetration depths of multiple propagating surface plasmon polaritons excited in the ring-hole nanoplasmonic sensors. A monolayer of bovine serum albumin (BSA) molecules with an effective thickness of 1.91 nm is detected and differentiated from a 10(-3) change in refractive index unit for the bulk solution. The noise level of the retrieved real-time sensor output compares favorably with that of traditional prism-based surface plasmon resonance sensors, but is achieved using a significantly simpler collinear transmission geometry and a miniaturized sensor footprint.
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Simultaneous Analysis of PhIP, 4'-OH-PhIP, and Their Precursors Using UHPLC-MS/MS.
J. Agric. Food Chem.
PUBLISHED: 11-20-2014
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A novel method allowing simultaneous analysis of PhIP, 4'-OH-PhIP, and their precursors (phenylalanine, tyrosine, creatine, creatinine, glucose) has been developed as a robust kinetic study tool by using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A direct hydrochloric acid (HCl) extraction was applied to achieve the simultaneous extraction of all seven analytes, with the mean recoveries ranging from 60% to 120% at two concentration levels. Then, an Atlantis dC18 column selected from four different chromatographic columns was ultimately used to separate these compounds within 15 min. The limits of detection range of allseven analytes were calculated as 0.14-325.00 ?g L(-1). The intra- and interday precision of the proposed method were less than 15.4 and 19.9%, respectively. The proposed method was successfully applied to depict the kinetic profiles of PhIP, 4'-OH-PhIP, and their precursors in pork model, reducing the analysis time and cost in the kinetic study.
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Structural dependence of silver nanowires on polyvinyl pyrrolidone (PVP) chain length.
Nanotechnology
PUBLISHED: 11-19-2014
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The effect of the chain length of polyvinyl pyrrolidone (PVP) on the structures of silver nanowires (AgNWs) is explored in this study. It was found in the experiments that PVP, when serving as a capping agent, has a great impact on the morphology and structure of AgNWs. By means of a series of experiments and the inquiry of the growth mechanism, the critical minimum PVP chain length for the successful formation of uniform nanowires was discovered, below which only nanoparticles or short nanorods can be obtained. Surprisingly, a core-shell structure of a nanowire with a polycrystal was observed when PVP with a very long chain length was employed in the processing.
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Stat3 promotes invasion of esophageal squamous cell carcinoma through up-regulation of MMP2.
Mol. Biol. Rep.
PUBLISHED: 11-10-2014
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Stat3 alters the expression of its downstream genes and is associated with tumor invasion and metastasis in several human cancers. Its role in esophageal squamous cell carcinoma (ESCC) has not been well characterized. We examined the tumor sections of 100 cases of ESCC by immunohistochemistry and observed significant overexpression of Stat3 in the cytoplasm of 89 % of ESCC cells and of phosphorylated Stat3 (p-Stat3) in the nuclei of 71 % of ESCC when compare with normal esophageal mucosa (72 %, p = 0.02; and 31 %, p = 0.001). Overexpression of Stat3 and p-Stat3 positively correlated with that of matrix metalloproteinase-2 (MMP2), a known regulator for cell migration, in 65 % of ESCC while only 26 % shown in benign esophageal mucosa. To further investigate the association of Stat3 with tumor metastasis in vitro, invasion of EC-1 cells (a human ESCC cell line) were investigated with Boyden chambers. The results showed that transfection of Stat3 not only promoted invasion of EC-1 cells but also significantly induced MMP2 expression in a dose-dependent manner. In contrast, suppressing expression of endogenous Stat3 mRNA and protein by Stat3 siRNA significantly reduced EC-1 cell invasion and MMP2 expression. A high-affinity Stat3-binding element was localized to the positions of 648-641 bp (TTCTCGAA) in the MMP2 promoter with electrophoretic mobility shift assay. Our results suggest that Stat3, p-Stat3, and MMP2 were overexpressed in ESCC and associated with invasion of ESCC; and Stat3 up-regulated expression of MMP2 in ESCC through directly binding to the MMP2 promoter.
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Evolution of invasion in a diverse set of fusobacterium species.
MBio
PUBLISHED: 11-06-2014
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The diverse Fusobacterium genus contains species implicated in multiple clinical pathologies, including periodontal disease, preterm birth, and colorectal cancer. The lack of genetic tools for manipulating these organisms leaves us with little understanding of the genes responsible for adherence to and invasion of host cells. Actively invading Fusobacterium species can enter host cells independently, whereas passively invading species need additional factors, such as compromise of mucosal integrity or coinfection with other microbes. We applied whole-genome sequencing and comparative analysis to study the evolution of active and passive invasion strategies and to infer factors associated with active forms of host cell invasion. The evolution of active invasion appears to have followed an adaptive radiation in which two of the three fusobacterial lineages acquired new genes and underwent expansions of ancestral genes that enable active forms of host cell invasion. Compared to passive invaders, active invaders have much larger genomes, encode FadA-related adhesins, and possess twice as many genes encoding membrane-related proteins, including a large expansion of surface-associated proteins containing the MORN2 domain of unknown function. We predict a role for proteins containing MORN2 domains in adhesion and active invasion. In the largest and most comprehensive comparison of sequenced Fusobacterium species to date, we have generated a testable model for the molecular pathogenesis of Fusobacterium infection and illuminate new therapeutic or diagnostic strategies.
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Sensitive impedimetric biosensor based on duplex-like DNA scaffolds and ordered mesoporous carbon nitride for silver(i) ion detection.
Analyst
PUBLISHED: 10-28-2014
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This study demonstrates a new, unlabeled immobilized DNA-based biosensor with ordered mesoporous carbon nitride material (MCN) for the detection of Ag(+) by electrochemical impedance spectroscopy (EIS) with [Fe(CN)6](4-/3-) as the redox couple. The unlabeled immobilized DNA initially formed the hairpin-like structure through hybridization with the probe, and then changed to duplex-like structure upon interaction with Ag(+) in solution to form a C-Ag(+)-C complex at electrode surface. As a result, the interfacial charge-transfer resistance of the electrode towards the [Fe(CN)6](4-/3-) redox couple was changed. Thus, a declined charge transfer resistance (Rct) was obtained, corresponding to Ag(+) concentration. MCN provide an excellent platform for DNA immobilization and faster electron transfer. Impedance data were analyzed with the help of Randles equivalent circuit. The lower detection limit of the biosensor for Ag(+) is 5 × 10(-11) M with good specificity. All results showed that this novel approach provides a reliable method for Ag(+) detection with sensitivity and specificity, potentially useful for practical applications. Moreover, other DNA detection methods for more heavy metals may be obtained from this idea and applied in the environmental field.
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The Effect of Heavy Metal-Induced Oxidative Stress on the Enzymes in White Rot Fungus Phanerochaete chrysosporium.
Appl. Biochem. Biotechnol.
PUBLISHED: 10-14-2014
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Prevalence of heavy metals in the living environment causes chemical stress and reactive oxygen species (ROS) formation in Phanerochaete chrysosporium (P. chrysosporium). However, the mechanisms involved in ROS defense are still under investigation. In the present study, we evaluated the effect of lead- and cadmium-induced oxidative stress on the activities of catalase (CAT), peroxidase (POD), lignin peroxidase (LiP), and manganese peroxidase (MnP). A time-dependent change in all enzyme activities was observed following exposure to 50 ?M cadmium and 25 ?M lead. The lowest values were recorded at 4 h after exposure. Both cadmium and lead inhibited CAT and POD. The cytochrome P450 (CYP450) levels increased under 50-100 ?M cadmium or lead exposure and decreased when heavy metal concentration was under 50 ?M; this suggested that ROS is not the only factor that alters the CYP450 levels. The cadmium removal rate in the sample containing 900 ?M taxifolin (inhibitor of CYP450) and 100 ?M cadmium was reduced to 12.34 %, 9.73 % lower than that of 100 ?M cadmium-induced sample, indicating CYP450 may play an indirect but key role in the process of clearance of heavy metals. The pH of the substrate solution decreased steadily during the incubation process.
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Mechanism of Cr(VI) reduction by Aspergillus niger: enzymatic characteristic, oxidative stress response, and reduction product.
Environ Sci Pollut Res Int
PUBLISHED: 10-13-2014
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Bioremediation of hexavalent chromium by Aspergillus niger was attributed to the reduction product (trivalent chromium) that could be removed in precipitation and immobilized inside the fungal cells and on the surface of mycelium. The site location of reduction was conducted with assays of the permeabilized cells, cell-free extracts, and cell debris, which confirmed that the chromate reductase was mainly located in the soluble fraction of cells. The oxidation-reduction process was accompanied by the increase of reactive oxygen species and antioxidant levels after hexavalent chromium treatment. Michaelis-Menten constant (K m) and maximum reaction rate (V max), obtained from the Lineweaver-Burk plot were 14.68 ?M and 434 ?M min(-1) mg(-1) of protein, respectively. Scanning electron microscopy and Raman spectra analyses manifested that both Cr(VI) and Cr(III) species were present on the mycelium. Fourier transform-infrared spectroscopy analysis suggested that carboxyl, hydroxide, amine, amide, cyano-group, and phosphate groups from the fungal cell wall were involved in chromium binding by the complexation with the Cr(III) and Cr(VI) species. A Cr(VI) removal mechanism of Cr(VI) reduction followed by the surface immobilization and intracellular accumulation of Cr(III) in living A. niger was present.
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Recovery of phosphorus from sewage sludge in combination with the supercritical water process.
Water Sci. Technol.
PUBLISHED: 09-27-2014
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In this paper, the fraction transformation and recovering of phosphorus (P) from sewage sludge (SS) residues, derived from supercritical water process, was investigated by extraction and precipitation processes. In addition, the form of heavy metals existing during the recovery process is also discussed. First, P in the solid residues was recovered by acid leaching with HCl, and then the derived P was adsorbed by activated alumina (Al(2)O(3)). Finally, the Al2O3 was desorbed with low concentration of NaOH. Results showed that 80% organic P was converted into HCl-P. The total P (the chief ingredient of HCl-P) in solid residue increased from 86.1 to 95.6% as temperature increased from 350 to 400 °C. The amount of P in the solid residue that was dissolved by 1 M HCl was 97.8%, and over 95% of P in the leaching solution (15 mg/L for P concentration) was adsorbed after 5.0 g of Al(2)O(3) powder was added. The amount of P desorbed from Al(2)O(3) with 0.1 M NaOH was 98.7%. Ultimately, over 85% of TP in SS was recovered. Moreover, the proportion of Cu, Zn and Pb in the extracted P products was lower than 5%.
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Soil organic carbon loss and selective transportation under field simulated rainfall events.
PLoS ONE
PUBLISHED: 08-28-2014
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The study on the lateral movement of soil organic carbon (SOC) during soil erosion can improve the understanding of global carbon budget. Simulated rainfall experiments on small field plots were conducted to investigate the SOC lateral movement under different rainfall intensities and tillage practices. Two rainfall intensities (High intensity (HI) and Low intensity (LI)) and two tillage practices (No tillage (NT) and Conventional tillage (CT)) were maintained on three plots (2 m width × 5 m length): HI-NT, LI-NT and LI-CT. The rainfall lasted 60 minutes after the runoff generated, the sediment yield and runoff volume were measured and sampled at 6-min intervals. SOC concentration of sediment and runoff as well as the sediment particle size distribution were measured. The results showed that most of the eroded organic carbon (OC) was lost in form of sediment-bound organic carbon in all events. The amount of lost SOC in LI-NT event was 12.76 times greater than that in LI-CT event, whereas this measure in HI-NT event was 3.25 times greater than that in LI-NT event. These results suggest that conventional tillage as well as lower rainfall intensity can reduce the amount of lost SOC during short-term soil erosion. Meanwhile, the eroded sediment in all events was enriched in OC, and higher enrichment ratio of OC (ERoc) in sediment was observed in LI events than that in HI event, whereas similar ERoc curves were found in LI-CT and LI-NT events. Furthermore, significant correlations between ERoc and different size sediment particles were only observed in HI-NT event. This indicates that the enrichment of OC is dependent on the erosion process, and the specific enrichment mechanisms with respect to different erosion processes should be studied in future.
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Cadmium induced oxalic acid secretion and its role in metal uptake and detoxification mechanisms in Phanerochaete chrysosporium.
Appl. Microbiol. Biotechnol.
PUBLISHED: 08-09-2014
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This study examines the role of oxalic acid in the uptake of Cd and participation in detoxification process in Phanerochaete chrysosporium. Cd-induced oxalic acid secretion was observed with growth inhibition and enzyme inactivation (LiP and MnP) of P. chrysosporium. The peak value of oxalic acid concentration was 16.6 mM at initial Cd concentration of 100 mg L(-1). During the short-term uptake experiments, the uptake of Cd was enhanced and accelerated in the presence of oxalic acid and resulted in alleviated growth and enzyme inhibition ratios. The formation of a metal-oxalate complex therefore may provide a detoxification mechanism via effect on metal bioavailability, whereby many fungi can survive and grow in environments containing high concentrations of toxic metals. The present findings will advance the understanding of fungal resistance to metal stress, which could show promise for a more useful application of microbial technology in the treatment of metal-polluted waste.
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Effects of Sodium Fluoride Treatment In Vitro on Cell Proliferation, BMP-2 and BMP-3 Expression in Human Osteosarcoma MG-63 Cells.
Biol Trace Elem Res
PUBLISHED: 08-05-2014
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Chronic excessive fluoride intake may cause fluorosis, which chiefly manifests as bone damage (or skeletal fluorosis). However, the molecular mechanism of skeletal fluorosis has not been clarified up to the present. The objective of this study was to analyze the effects of fluoride treatment on two of bone morphogenetic protein family member (BMP-2 and BMP-3) expression and cell viability using human osteosarcoma MG-63 cells as a model. Sodium fluoride (NaF) had pro-proliferation effects at relatively moderate concentration, with 5?×?10(3) ?mol/L having the best effects. At 2?×?10(4) ?mol/L, NaF inhibits cell proliferation. BMP-2 and BMP-3 expression was significantly induced by 5?×?10(3) ?mol/L NaF and, to lesser extent, by 2?×?10(4) ?mol/L NaF. Correspondingly, mothers against decapentaplegic homolog 1 (Smad-1) increased at both doses of NaF, which indicated the BMP signaling pathway was activated. Notable increases in secreted alkaline phosphatase (ALP) were observed when cells were treated with 5?×?10(3) ?mol/L NaF. A BMP specific inhibitor LDN193189 suppressed cell proliferation induced by 5?×?10(3) ?mol/L NaF. Also, 2?×?10(4) ?mol/L NaF induced apoptosis but likely through a mechanism unrelated to the BMP pathway. Collectively, data show that NaF had dose-dependent effects on cell proliferation as well as BMP-2 and BMP-3 expression in MG-63 cells and suggested that cell proliferation enhanced by NaF-induced BMP members may be a molecular mechanism underlying skeletal fluorosis.
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Fast adsorption of Cd²? and Pb²? by EGTA dianhydride (EGTAD) modified ramie fiber.
J Colloid Interface Sci
PUBLISHED: 08-04-2014
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In this study, the removal of Cd(2+) and Pb(2+) from aqueous solutions was investigated using a novel chelating material. The first part described the synthesis of ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid dianhydride (EGTAD), mercerization treatment of ramie fiber (MRF), and the MRF was then reacted with EGTAD to prepare the new material (ERF). The obtained material was characterized by weight gain, SEM, FTIR, and elemental analysis. The results of FTIR and elemental analysis confirmed that ester bond, carboxyl and amine groups were introduced onto ERF. The adsorption capacity of metals on ERF was evaluated at different contact times, pH values, initial metal concentrations, and temperatures in the second part. The adsorption equilibrium was reached within 5 min for Cd(2+) and Pb(2+). Adsorption isotherm could be well fitted by the Langmuir model, and the maximum adsorption capacities were 159.11 and 273.78 mg g(-1) for Cd(2+) and Pb(2+) at 298 K, respectively. Thermodynamic analysis showed that the adsorption process was spontaneous and endothermic. The molar ratio of adsorbed cation to grafted EGTA is close to 1.8:1, which confirmed that the adsorption was chemical process involving both surface chelation reaction and ion exchange. In addition, the absorbent was successfully regenerated using HCl and ultrasonic treatment.
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Genome Sequence of Fusarium oxysporum f. sp. melonis Strain NRRL 26406, a Fungus Causing Wilt Disease on Melon.
Genome Announc
PUBLISHED: 08-02-2014
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Horizontal chromosome transfer introduces host-specific pathogenicity among members of the Fusarium oxysporum species complex and is responsible for some of the most destructive and intractable plant diseases. This paper reports the genome sequence of F. oxysporum f. sp. melonis (NRRL 26406), a causal agent of Fusarium wilt disease on melon.
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A restoration-promoting integrated floating bed and its experimental performance in eutrophication remediation.
J Environ Sci (China)
PUBLISHED: 08-01-2014
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Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the processes of water purification and macrophyte restoration simultaneously. Two outdoor experiments were conducted to evaluate the ecological functions of the RPIFB. Trial 1 was conducted to compare the eutrophication purification among floating bed, gradual-submerging bed (GSB) and RPIFB technologies. The results illustrated that RPIFB has the best purification capacity. Removal efficiencies of RPIFB for TN, TP, NH(+)4-N, NO(-)3-N, CODCr, Chlorophyll-a and turbidity were 74.45%, 98.31%, 74.71%, 88.81%, 71.42%, 90.17% and 85%, respectively. In trial 2, influences of depth of GSB and photic area in RPIFB on biota were investigated. When the depth of GSB decreased and the photic area of RPIFB grew, the height of Potamogeton crispus Linn. increased, but the biomass of Canna indica Linn. was reduced. The mortalities of Misgurnus anguillicaudatus and Bellamya aeruginosa in each group were all less than 7%. All results indicated that when the RPIFB was embedded into the eutrophic water, the regime shift from phytoplankton-dominated to macrophyte-dominated state could be promoted. Thus, the RPIFB is a promising remediation technology for eutrophication and submerged macrophyte restoration.
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[Purification and characterization of the biosurfactant rhamnolipid].
Se Pu
PUBLISHED: 07-03-2014
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Biosurfactant rhamnolipid is a metabolic intermediate produced by microorganisms under a certain condition. There are the polar hydrophilic group and the non-polar hydrophobic group in rhamnolipid molecule which always exhibits high surface or interfacial activity. A reliable separation and purification method as well as component identification technique is essential for success of production process. The rhamnolipid was produced by aerobic fermentation using Pseudomonas aeruginosa CCTCC AB93066 in this study. It was separated from the culture by acid precipitation and purified by column chromatography until two groups of monorhamnolipid and dirhamnolipid were obtained. High performance liquid chromatography with mass spectrometry (HPLC-MS) examination showed that either the monorhamnolipid or the dirhamnolipid contained three major species. They were RhaC10C10, RhaC10C12-H2, RhaC10C12 for monorhamnolipid and Rha2C10 C10, Rha2C10 C12-H2, Rha2 C10 C12 for dirhamnolipid. The results of the study suggested that Pseudomonas aeruginosa CCTCC AB93066 is a good strain for rhamnolipid production. Acid precipitation-column chromatography technique is good for purification of rhamnolipid. Meanwhile, HPLC-MS is a reliable method for identifying components of rhamnolipid with high sensitivity and accuracy.
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Effect of exogenous nitric oxide on antioxidative system and S-nitrosylation in leaves of Boehmeria nivea (L.) Gaud under cadmium stress.
Environ Sci Pollut Res Int
PUBLISHED: 06-28-2014
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Cadmium (Cd)-induced growth inhibition is one of the primary factors limiting phytoremediation effect of Boehmeria nivea (L.) Gaud in contaminated soil. Sodium nitroprusside (SNP), a donor of nitric oxide (NO), has been evidenced to alleviate Cd toxicity in many plants. However, as an important mechanism of NO in orchestrating cellular functions, S-nitrosylation is still poorly understood in its relation with Cd tolerance of plants. In this study, higher exogenous NO levels were found to coincide with higher S-nitrosylation level expressed as content of S-nitrosothiols (SNO). The addition of low concentration (100 ?M) SNP increased the SNO content, and it simultaneously induced an alleviating effect against Cd toxicity by enhancing the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) and reduced the accumulation of H2O2 as compared with Cd alone. Application of S-nitrosoglutathione reductase (GSNOR) inhibitors dodecanoic acid (DA) in 100 ?M SNP group brought in an extra elevation in S-nitrosylation level and further reinforced the effect of SNP. While the additions of 400 ?M SNP and 400 ?M SNP?+?50 ?M DA further elevated the S-nitrosylation level, it markedly weakened the alleviating effect against Cd toxicity as compared with the addition of 100 ?M SNP. This phenomenon could be owing to excess consumption of glutathione (GSH) to form SNO under high S-nitrosylation level. Therefore, the present study indicates that S-nitrosylation is involved in the ameliorating effect of SNP against Cd toxicity. This involvement exhibited a concentration-dependent property.
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IL17A gene polymorphisms, serum IL-17A and IgE levels, and hepatocellular carcinoma risk in patients with chronic hepatitis B virus infection.
Mol. Carcinog.
PUBLISHED: 06-25-2014
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Interleukin (IL)-17A plays important roles in hepatitis B virus (HBV)-induced liver diseases. This study aims to investigate IL17A single nucleotide polymorphisms (SNPs) and the predispositions to chronic HBV infection and hepatocellular carcinoma (HCC) risk and the correlations to IL-17A and IgE levels. Three hundred ninety-five chronic HBV patients, 75 HBV infection resolvers, and 174 healthy controls were included. IL17A SNPs rs8193036 (C/T) and rs2275913 (A/G) and serum IL-17A and IgE levels were determined. HBV infection resolvers had higher rs8193036 allele T and allele T-containing genotypes than HBV patients or controls. Compared with chronic hepatitis, HCC patients had more frequent rs2275913 genotype GG (odds ratios [OR] 3.317, 95% confidence interval [CI] 1.663-6.617, P?=?0.001) and allele G (OR 1.844, 95% CI 1.311-2.595, P?
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Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.
Environ Int
PUBLISHED: 06-20-2014
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Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections.
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[Establishment of a lentivirus-mediated rapid eukaryotic expression system of novel avian influenza H7N9 virus hemagglutinin gene].
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi
PUBLISHED: 06-10-2014
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To establish a rapid eukaryotic expression system of hemagglutinin (HA) gene of novel avian influenza H7N9 using lentiviral vector, express the recombinant protein and study its functions in human embryonic kidney HEK293T cells.
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Authentication of Polygonati Odorati Rhizoma and other two Chinese Materia Medica of the Liliaceae family by pharmacognosy technique with GC-MS analysis.
Microsc. Res. Tech.
PUBLISHED: 05-29-2014
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Yuzhu (Polygonati Odorati Rhizoma), Kangdingyuzhu (Polygonati Prattii Rhizoma), and zhugenqiyuzhu (Disporopsis Fuscopictae Rhizoma) are of the same family, but of different genera. They have all often used in Chinese Materia Medica (CMM) as Polygonati Odorati Rhizoma in China market. Three species of CMM are confused. For better application, we need to identify these plants accurately. This study use pharmacognosy technique and GC-MS analysis, three species of CMM were authenticated. In macroscopic characteristics, the fruit of Polygonati Odorati Rhizoma is blue-black, while the other two are maroon and dark purple orderly. Nodes of Polygonati Odorati Rhizoma are upward and light uplift, about 1 cm spacing, while the other are not. As for microscopic characteristics, the cortex of Polygonati Odorati Rhizoma only occupies about 1/5 of the radius of the transverse section with inconspicuous endodermis, which is much smaller than others. The type of vascular bundles of Polygonati Odorati Rhizoma is closed collateral, but the other is amphivasal. Raphides of calcium oxalate are scattered, but Raphides of the other two are like brooms and neat rows. GC-MS analysis of essential oil could provide different characteristics to distinguish three species. Twenty-three compounds were identified from essential oil of Polygonati Odorati Rhizoma and the main components were n-hexadecanoic acid (49.45%), while n-hexadecanoic acid of the other two are 23.92% and 9.45%. The content of n-hexadecanoic is strongly different. This research was aimed to establish a method by pharmacognosy and GC-MS analysis to identify three CMM and for providing scientifical data to ensure accuracy of origin of three species. Microsc. Res. Tech., 2014. © 2014 Wiley Periodicals, Inc.
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Genome Sequence of the Pathogenic Fungus Sporothrix schenckii (ATCC 58251).
Genome Announc
PUBLISHED: 05-24-2014
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Sporothrix schenckii is a pathogenic dimorphic fungus that grows as a yeast and as mycelia. This species is the causative agent of sporotrichosis, typically a skin infection. We report the genome sequence of S. schenckii, which will facilitate the study of this fungus and of the Sporothrix schenckii group.
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Study on biodegradation process of lignin by FTIR and DSC.
Environ Sci Pollut Res Int
PUBLISHED: 05-19-2014
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The biodegradation process of lignin by Penicillium simplicissimum was studied to reveal the lignin biodegradation mechanisms. The biodegradation products of lignin were detected using Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer, different scanning calorimeter (DSC), and stereoscopic microscope. The analysis of FTIR spectrum showed the cleavage of various ether linkages (1,365 and 1,110 cm(-1)), oxidation, and demethylation (2,847 cm(-1)) by comparing the different peak values in the corresponding curve of each sample. Moreover, the differences (Tm and ?Hm values) between the DSC curves indirectly verified the FTIR analysis of biodegradation process. In addition, the effects of adding hydrogen peroxide (H2O2) to lignin biodegradation process were analyzed, which indicated that H2O2 could accelerate the secretion of the MnP and LiP and improve the enzymes activity. What is more, lignin peroxidase and manganese peroxidase catalyzed the lignin degradation effectively only when H2O2 was presented.
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Fate and risk assessment of heavy metals in residue from co-liquefaction of Camellia oleifera cake and sewage sludge in supercritical ethanol.
Bioresour. Technol.
PUBLISHED: 05-06-2014
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The fate and risk assessment of heavy metals (HMs) in solid residue from co-liquefaction of sewage sludge (SS) and Camellia oleifera cake (COC) in supercritical ethanol (SCE) were investigated. SCE effectively stabilized HMs in solid residues and a better stabilization was presented on Zn than Cd. Moreover, SCE significantly transformed Cd, Cu and Zn into F4, which reduced the risk to the environment. Furthermore, risk assessments of Igeo, Er(i), RI and RAC demonstrated that the addition of COC was beneficial to the contamination decrement of HMs since pollution levels of HMs all decreased after treatment, and the lowest pollution level was obtained with SC-350. Therefore, SS treated by SCE with the addition of COC could be a promising technology for disposal of SS, especially considering the safety of COC as regards HMs problem.
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Quantum dots and p-phenylenediamine based method for the sensitive determination of glucose.
Talanta
PUBLISHED: 05-02-2014
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By introducing p-phenylenediamine (PPD) to the hybrid system of Mn-doped CdS/ZnS quantum dots (QDs) and glucose oxidase (GOD), a sensitive label-free method was proposed for direct detection of glucose. With glucose and PPD as substrates, 2,5-diamino-N,N'-di-(4-aminophenyl)-2,5-cyclohexadiene-1,4-diimine (DDACD) that intensively quenches the fluorescence of QDs can be produced by the catalysis of GOD. A detection limit as low as 3.2 ?M was obtained with the high-efficient fluorescence quencher. Two linear ranges, from 5.0 ?M to 1000 ?M and from 1.0 mM to 10.0 mM, were identified between time-gated fluorescence intensity and the concentration of glucose. It is shown that the newly proposed methods have high selectivity for glucose over other saccharides and coexisting biological species in serum. The method can be used directly to determine glucose in normal adult human serum without any complicated sample pretreatments. The recovery rate and repeatability of the method were also shown to be satisfactory.
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Role of low-concentration monorhamnolipid in cell surface hydrophobicity of Pseudomonas aeruginosa: adsorption or lipopolysaccharide content variation.
Appl. Microbiol. Biotechnol.
PUBLISHED: 04-20-2014
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A role of rhamnolipid biosurfactant to enhance the biodegradation of hydrocarbons is known to be enhancing bacterial cell surface hydrophobicity (CSH) and adhesion of cells to hydrocarbons. Assumptions regarding the mechanism for rhamnolipid in changing CSH of Gram-negative bacteria are rhamnolipid-induced release of lipopolysaccharide (LPS) from the cell's outer membrane and adsorption/orientation of rhamnolipid on the cell surface. In this study, the relation between cell-wall LPS or rhamnolipid content and CSH of a Pseudomonas aeruginosa bacterium subjected to rhamnolipid treatment was investigated to add insights to the mechanism. Results showed that the initial CSH was determined by the type of substrate the cells grow on and the stage of growth. For glucose-grown cells with low initial CSH and high LPS content, rhamnolipid sorption in cell wall had no discernable effect on CSH. For cells grown on glycerol with medium initial CSH and low LPS content, rhamnolipid sorption increased CSH of exponential-phase cells but decreased that of stationary-phase cells. For hexadecane-grown cells with high initial CSH and high LPS content, rhamnolipid sorption decreased CSH of both exponential-phase and stationary-phase cells. The results indicated that CSH has a better correlation to the content of rhamnolipid in the cell wall than to the content of LPS in the presence of rhamnolipid treatment and that rhamnolipid adsorption may be an important mechanism for rhamnolipid to alter CSH of P. aeruginosa.
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Adsorptive removal of methylene blue by rhamnolipid-functionalized graphene oxide from wastewater.
Water Res.
PUBLISHED: 04-19-2014
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In this article, a rhamnolipid-functionalized graphene oxide (RL-GO) hybrid was prepared by one-step ultrasonication and adsorptive removal of methylene blue (MB) from both artificial and real wastewater by the RL-GO was investigated. The Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) area and Zeta potential analysis were used to characterize the adsorbent. The results showed that RL-GO had abundant functional groups and a mesopores feature. MB adsorption by the RL-GO increased with increase in adsorbent dose, pH, temperature and initial MB concentration, while it was insensitive to ionic strength variation. The adsorption kinetics fitted well to the pseudo-second-order model with correlation coefficients greater than 0.999. The Intra-particle diffusion and Boyd's film-diffusion models showed that the rate-controlled step was dominated by film-diffusion in the beginning and then followed by intra-particle diffusion. The adsorption isotherm was fitted by adsorption models with the suitability in order of BET > Freundlich > Langmuir > Temkin, based on comparison between correlation coefficients. Thermodynamic analysis of equilibriums suggested that the adsorption MB on RL-GO was spontaneous and endothermic. The adsorption mechanism was also proposed to be electrostatic attraction, ?-? interaction and hydrogen bond. In addition, the real wastewater experiment, the regeneration study and the comparative cost analysis showed that the RL-GO composites could be a cost-effective and promising sorbent for MB wastewater treatment owing to its high efficiency and excellent reusability.
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The migration and transformation behavior of heavy metals during the liquefaction process of sewage sludge.
Bioresour. Technol.
PUBLISHED: 04-08-2014
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Bio-oils and bio-chars were obtained from sewage sludge (SS) by liquefaction with ethanol (or acetone) as the solvent at the temperature of 280, 320 and 360°C. The migration and transformation of HMs as Pb, Zn, Cu and Ni during liquefaction were thoroughly investigated. Meanwhile, the environmental risk of HMs in the bio-oils and bio-chars was assessed according to the risk assessment code (RAC). The results showed that the liquefaction solvent and temperature significantly affected the redistribution of HMs. HMs distributed mainly into the bio-chars, with less than 10% into the bio-oils. Increasing liquefaction temperature would promote a higher HM content in bio-oils. The environmental risk of HMs in bio-chars was mitigated compared to SS, especially for Ni. However, the environmental risk of Zn and Ni in bio-oils was undesirably high in comparison with bio-chars. It was suggested that the bio-oil should be pretreated before utilization.
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Pyrolysis Oil-Based Lipid Production as Biodiesel Feedstock by Rhodococcus opacus.
Appl. Biochem. Biotechnol.
PUBLISHED: 04-01-2014
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Light oil from pyrolysis, which accounts for ?10 % carbon yield of the starting biomass, is a complex aqueous product that is difficult to utilize and usually discarded. This work presents the feasibility of light oil as a sole carbon source to support the growth of Rhodococcus opacus (R. opacus) that in turn accumulate triacylglycerols as biodiesel feedstock. Two types of bacteria (R. opacus PD630 and DSM 1069) were selected in this study. Research results showed that after short adaption periods both strains can grow well on this complex carbon source, as proved by the consumption of oligomers and monomers in light oil. Lipid content by R. opacus PD630 and DSM 1069 was observed up to 25.8 % and 22.0 % of cell dry weight, respectively. Palmitic and stearic acids were found to be the predominant fatty acids in these bacterial cells. In addition, the light oil-based lipid production can be enhanced by reducing the pH value from 7 to 4, especially in case of DSM 1069.
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Analysis of the genome and transcriptome of Cryptococcus neoformans var. grubii reveals complex RNA expression and microevolution leading to virulence attenuation.
PLoS Genet.
PUBLISHED: 04-01-2014
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Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence.
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Effects of d-menthol stress on the growth of and microcystin release by the freshwater cyanobacterium Microcystis aeruginosa FACHB-905.
Chemosphere
PUBLISHED: 03-27-2014
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The effects of d-menthol on the growth of Microcystis aeruginosa FACHB-905 and microcystin (MCY) concentration were evaluated by batch culture experiments. The algal biomass and the intracellular and extracellular MCY concentrations were evaluated during 5d incubation. After the d-menthol exposure, the dry weight of the cells gradually decreased; the decrease in the dry weight after 5d exposure was 29, 12, and 2mgL(-1) when the initial cell densities were 1.4×10(7), 1.2×10(6), and 2.9×10(5)cellmL(-1), respectively. The results indicate that the d-menthol exposure inhibited the cellular growth, thus also inhibiting the increase of the total MCY concentration. In the presence of d-menthol, the intracellular MCY was gradually released into the medium after the cell lysis. The extracellular MCY concentration in the medium was significantly higher in the d-menthol-exposed samples than in the control samples, confirming that d-menthol cannot decompose the extracellular MCY.
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Phanerochaete chrysosporium inoculation shapes the indigenous fungal communities during agricultural waste composting.
Biodegradation
PUBLISHED: 03-27-2014
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Inoculation with exogenous white-rot fungi has been proven to be an efficient method to promote lignocellulose biodegradation during agricultural waste composting. Indigenous fungal communities, the most important organisms responsible for mineralization and decomposition of lignocellulosic materials in composts, can be affected by sample properties and other biotic factors. This research was conducted to determine the effects of the Phanerochaete chrysosporium inoculation on the indigenous fungal communities during agricultural waste composting. Fungal communities in samples with different inoculation regimes were investigated by sequencing and quantitative PCR. Results showed that P. chrysosporium inoculants produced significant negative effects on the indigenous fungal community abundance during the thermophilic stage. Samples inoculated during Phase II contained higher proportion of Acremonium chrysogenum and Galactomyces geotrichum, while those non-inoculated samples were dominated by Coprinopsis cinerea and Scytalidium thermophilum. Moreover, the indigenous fungal community abundance was significantly correlated with the C/N ratio, water soluble carbon and moisture content (P < 0.05). Redundancy analysis indicated that the most variation in distribution of indigenous fungal community structure was statistically explained by nitrate, C/N ratio, and moisture content, factors which solely explained 29.6 % (F = 30.316, P = 0.002), 25.6 % (F = 26.191, P = 0.002) and 10.0 % (F = 10.249, P = 0.002) of the variation in the indigenous fungal community structure, respectively.
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Diversity of two-domain laccase-like multicopper oxidase genes in Streptomyces spp.: identification of genes potentially involved in extracellular activities and lignocellulose degradation during composting of agricultural waste.
Appl. Environ. Microbiol.
PUBLISHED: 03-21-2014
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Traditional three-domain fungal and bacterial laccases have been extensively studied for their significance in various biotechnological applications. Growing molecular evidence points to a wide occurrence of more recently recognized two-domain laccase-like multicopper oxidase (LMCO) genes in Streptomyces spp. However, the current knowledge about their ecological role and distribution in natural or artificial ecosystems is insufficient. The aim of this study was to investigate the diversity and composition of Streptomyces two-domain LMCO genes in agricultural waste composting, which will contribute to the understanding of the ecological function of Streptomyces two-domain LMCOs with potential extracellular activity and ligninolytic capacity. A new specific PCR primer pair was designed to target the two conserved copper binding regions of Streptomyces two-domain LMCO genes. The obtained sequences mainly clustered with Streptomyces coelicolor, Streptomyces violaceusniger, and Streptomyces griseus. Gene libraries retrieved from six composting samples revealed high diversity and a rapid succession of Streptomyces two-domain LMCO genes during composting. The obtained sequence types cluster in 8 distinct clades, most of which are homologous with Streptomyces two-domain LMCO genes, but the sequences of clades III and VIII do not match with any reference sequence of known streptomycetes. Both lignocellulose degradation rates and phenol oxidase activity at pH 8.0 in the composting process were found to be positively associated with the abundance of Streptomyces two-domain LMCO genes. These observations provide important clues that Streptomyces two-domain LMCOs are potentially involved in bacterial extracellular phenol oxidase activities and lignocellulose breakdown during agricultural waste composting.
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Mesoporous carbon nitride based biosensor for highly sensitive and selective analysis of phenol and catechol in compost bioremediation.
Biosens Bioelectron
PUBLISHED: 03-19-2014
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Herein, we reported here a promising biosensor by taking advantage of the unique ordered mesoporous carbon nitride material (MCN) to convert the recognition information into a detectable signal with enzyme firstly, which could realize the sensitive, especially, selective detection of catechol and phenol in compost bioremediation samples. The mechanism including the MCN based on electrochemical, biosensor assembly, enzyme immobilization, and enzyme kinetics (elucidating the lower detection limit, different linear range and sensitivity) was discussed in detail. Under optimal conditions, GCE/MCN/Tyr biosensor was evaluated by chronoamperometry measurements and the reduction current of phenol and catechol was proportional to their concentration in the range of 5.00 × 10(-8)-9.50 × 10(-6)M and 5.00 × 10(-8)-1.25 × 10(-5)M with a correlation coefficient of 0.9991 and 0.9881, respectively. The detection limits of catechol and phenol were 10.24 nM and 15.00 nM (S/N=3), respectively. Besides, the data obtained from interference experiments indicated that the biosensor had good specificity. All the results showed that this material is suitable for load enzyme and applied to the biosensor due to the proposed biosensor exhibited improved analytical performances in terms of the detection limit and specificity, provided a powerful tool for rapid, sensitive, especially, selective monitoring of catechol and phenol simultaneously. Moreover, the obtained results may open the way to other MCN-enzyme applications in the environmental field.
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Source identification and potential ecological risk assessment of heavy metals in PM2.5 from Changsha.
Sci. Total Environ.
PUBLISHED: 03-18-2014
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The probable sources and potential ecological risks of Cu, Zn, Cd and Pb in PM2.5 in Changsha were analyzed. The intelligent medium-flow total suspended particle sampler was used to collect the PM2.5 samples from Yuelu (YL), Kaifu (KF), and Yuhua (YH) districts of Changsha in March-April of 2013. The total concentration of heavy metals (HMs) in PM2.5 was used for source identification by correlation coefficients and principal component analysis (PCA). Otherwise the potential ecological risks indices (RIs) were calculated based on the bioavailable fractions of HMs which were obtained through BCR sequential extraction. Almost 50% of Cu, Cd and Pb in PM2.5 of all sites were accumulated in soluble and reducible fractions by speciation analysis. The correlation coefficients and PCA analysis showed that HMs in PM2.5 of Changsha in spring were mainly from vehicular emissions, fuel combustion, resuspension of dust and other pollution sources. The average potential ecological RIs of HMs in PM2.5 of Changsha were 6193.80 which suggests that HMs in PM2.5 was extremely serious. These results would be a good reference for health studies and formulation of environmental regulations.
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Co-pelletization of sewage sludge and biomass: the density and hardness of pellet.
Bioresour. Technol.
PUBLISHED: 03-12-2014
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In the present study, the effects of process parameters on pellet properties were investigated for the co-pelletization of sludge and biomass materials. The relaxed pellet density and Meyer hardness of pellets were identified. Scanning electron microscopy, FT-IR spectra and chemical analysis were conducted to investigate the mechanisms of inter-particular adhesion bonding. Thermogravimetric analysis was applied to investigate the combustion characteristics. Results showed that the pellet density was increased with the parameters increasing, such as pressure, sludge ratio and temperature. High hardness pellets could be obtained at low pressure, temperature and biomass size. The optimal moisture content for co-pelletization was 10-15%. Moreover, the addition of sludge can reduce the diversity of pellet hardness caused by the heterogeneity of biomass. Increasing ratio of sludge in the pellet would slow down the release of volatile. Synergistic effects of protein and lignin can be the mechanism in the co-pelletization of sludge and biomass.
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Removal of malachite green dye from wastewater by different organic acid-modified natural adsorbent: kinetics, equilibriums, mechanisms, practical application, and disposal of dye-loaded adsorbent.
Environ Sci Pollut Res Int
PUBLISHED: 03-11-2014
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Natural adsorbent (Cinnamomum camphora sawdust) modified by organic acid (oxalic acid, citric acid, and tartaric acid) was investigated as a potential adsorbent for the removal of hazardous malachite green (MG) dye in aqueous media in a batch process. The extent of MG adsorption onto modified sawdust increased with increasing organic acid concentrations, pH, contact time, and temperature but decreased with increasing adsorbent dosage and ionic strength. Kinetic study indicated that the pseudo-second-order kinetic model could best describe the adsorption kinetics of MG. Equilibrium data were found to fit well with the Langmuir model, and the maximum adsorption capacity of the three kinds of organic acid-modified sawdust was 280.3, 222.8, and 157.5 mg/g, respectively. Thermodynamic parameters suggested that the sorption of MG was an endothermic process. The adsorption mechanism, the application of adsorbents in practical wastewater, the prediction of single-stage batch adsorption system, and the disposal of depleted adsorbents were also discussed.
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Estrogen is a novel regulator of Tnfaip1 in mouse hippocampus.
Int. J. Mol. Med.
PUBLISHED: 02-26-2014
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Tumor necrosis factor?induced protein 1 (Tnfaip1), also known as B12, has been previously identified as a tumor necrosis factor-? (TNF-?)-inducible protein and is involved in the cytokinesis signaling pathway, DNA synthesis, innate immunity, cell apoptosis, Alzheimer's disease (AD) and type 2 diabetic nephropathy. However, little is known regarding the expression of Tnfaip1 in various tissues or its accurate role in these physiological functions. The focus of this study was on Tnfaip1 expression in different tissues, with a high expression in mouse hippocampus being identified. The age- and gender?related expression of Tnfaip1 in hippocampus was also investigated. The distribution of Tnfaip1 was mapped using fluorescent immunostaining. Although immunoactivity was found in the CA1, CA3 and DG subregions of the hippocampus in E17.5 and P6 mice, strong staining was only detected in the CA3 subregion in adult mice. These data suggested that Tnfaip1 expression in hippocampus may be regulated by estrogen. Further study showed that the expression of Tnfaip1 in the hippocampus was significantly increased in ovariecto-mized mice compared to Sham mice. In cultured primary hippocampal cells, Tnfaip1 showed different expression levels in different treatments of estrogen or estrogen receptor antagonists. Additional experiments demonstrated the existence of a binding site of ER? in the Tnfaip1 promoter region, and that ER? was able to upregulate Tnfaip1 expression. Our study identified a new regulatory factor and a primary regulatory mechanism of Tnfaip1 expression in hippocampus. Since both hippocampus and estrogen are crucial in AD, the results also showed a potential association between Tnfaip1 and hippocampal-related diseases, such as AD, which may be affected by the estrogen level.
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Iron improving bio-char derived from microalgae on removal of tetracycline from aqueous system.
Environ Sci Pollut Res Int
PUBLISHED: 02-19-2014
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Novel magnetic carbonaceous bio-char was hydrothermal prepared from microalgae under different loadings of iron and its structures and surface chemistry were characterized with Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm (BET). The morphology of bio-char changed from sheet to particle as iron loading increased and its surface area also increased. When 3.0 g of dried microalgae and 6.0 mmol iron salt ((NH4)2SO4·FeSO4·6H2O) were mixed and treated, the obtained bio-char possessing the highest amount of oxygen-containing functional groups resulted in the best adsorption performance on tetracycline (TC). This adsorption process was fitted to Langmuir adsorption isotherm and the maximum adsorption capacity was 95.86 mg/g, which is higher than other bio-char reported. The iron loading contributed to the higher adsorption capacity of bio-char, which may be due to three factors, the high surface area, more hydrogen bonding, and bridging effects of the structural Fe for TC. Our data suggest that bio-char may have more important role in stabilization of pollutants in the environment.
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Influence of sewage sludge-based activated carbon and temperature on the liquefaction of sewage sludge: yield and composition of bio-oil, immobilization and risk assessment of heavy metals.
Bioresour. Technol.
PUBLISHED: 02-12-2014
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The influence of sewage sludge-based activated carbons (SSAC) on sewage sludge liquefaction has been carried out at 350 and 400°C. SSAC increased the yield and energy density of bio-oil at 350°C. The metallic compounds were the catalytic factor of SSAC obtained at 550°C (SSAC-550), while carbon was the catalytic factor of SSAC obtained at 650°C. Liquefaction with SSAC redistributed the species of heavy metals in solid residue (SR). With the addition of SSAC, the risk of Cu, Zn and Pb decreased at 350°C, while at 400°C the risk of Cd, Cu, and Zn were decreased. Ecological risk index indicated that 400°C was preferable for the toxicity decrement of SR, while risk assessment code indicated that SR obtained at 350°C contained lower risk. Considering the bio-oil yield, liquefaction at 350°C with SSAC-550 was preferable.
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Comparative genomic and transcriptomic analysis of wangiella dermatitidis, a major cause of phaeohyphomycosis and a model black yeast human pathogen.
G3 (Bethesda)
PUBLISHED: 02-06-2014
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Black or dark brown (phaeoid) fungi cause cutaneous, subcutaneous, and systemic infections in humans. Black fungi thrive in stressful conditions such as intense light, high radiation, and very low pH. Wangiella (Exophiala) dermatitidis is arguably the most studied phaeoid fungal pathogen of humans. Here, we report our comparative analysis of the genome of W. dermatitidis and the transcriptional response to low pH stress. This revealed that W. dermatitidis has lost the ability to synthesize alpha-glucan, a cell wall compound many pathogenic fungi use to evade the host immune system. In contrast, W. dermatitidis contains a similar profile of chitin synthase genes as related fungi and strongly induces genes involved in cell wall synthesis in response to pH stress. The large portfolio of transporters may provide W. dermatitidis with an enhanced ability to remove harmful products as well as to survive on diverse nutrient sources. The genome encodes three independent pathways for producing melanin, an ability linked to pathogenesis; these are active during pH stress, potentially to produce a barrier to accumulated oxidative damage that might occur under stress conditions. In addition, a full set of fungal light-sensing genes is present, including as part of a carotenoid biosynthesis gene cluster. Finally, we identify a two-gene cluster involved in nucleotide sugar metabolism conserved with a subset of fungi and characterize a horizontal transfer event of this cluster between fungi and algal viruses. This work reveals how W. dermatitidis has adapted to stress and survives in diverse environments, including during human infections.
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[Expression and identification of enterohemorrhagic Escherichia coli O157:H7 Shiga toxin1A subunit].
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi
PUBLISHED: 02-05-2014
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To express and identify enterohemorrhagic Escherichia coli (EHEC) O157:H7 Shiga toxin 1 A subunit (Stx1A).
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Characterization and application of bioflocculant prepared by Rhodococcus erythropolis using sludge and livestock wastewater as cheap culture media.
Appl. Microbiol. Biotechnol.
PUBLISHED: 01-22-2014
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A new bioflocculant was produced by culturing Rhodococcus erythropolis in a cheap medium. When culture pH was 7.0, inoculum size was 2 % (v/v), Na2HPO4 concentration was 0.5 g L(-1), and the ratio of sludge/livestock wastewater was 7:1 (v/v), a maximum flocculating rate of 87.6 % could be achieved. Among 13 different kinds of pretreatments for sludge, the optimal one was the thermal-alkaline pretreatment. Different from a bioflocculant produced in a standard medium, this bioflocculant was effective over a wide pH range from 2 to 12 with flocculating rates higher than 98 %. Approximately, 1.6 g L(-1) of crude bioflocculant could be harvested using cold ethanol for extraction. This bioflocculant showed color removal rates up to 80 % when applied to direct and disperse dye solutions, but only 23.0 % for reactive dye solutions. Infrared spectrum showed that the bioflocculant contained functional groups such as -OH, -NH2, and -CONH2. Components in the bioflocculant consisted of 91.2 % of polysaccharides, 7.6 % of proteins, and 1.2 % of DNA. When the bioflocculant and copper sulfate (CuSO4) were used together for decolorization in actual dye wastewater, the optimum decolorization conditions were specified by the response surface methodology as pH 11, bioflocculant dosage of 40 mg/L, and CuSO4 80 mg/L, under which a decolorization rate of 93.9 % could be reached.
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Hydrogen sulfide alleviates 2,4-dichlorophenol toxicity and promotes its degradation in Phanerochaete chrysosporium.
Chemosphere
PUBLISHED: 01-21-2014
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In this study, the H2S donor, sodium hydrosulfide (NaHS) was used to pretreat Phanerochaete chrysosporium in order to improve its ability to degrade 2,4-dichlorophenol (2,4-DCP). When pretreated with 100?M NaHS, P. chrysosporium was able to degrade 2,4-DCP completely in 24h, whereas the degradation efficiency of the untreated control was only 57%. The 2,4-DCP-induced oxidative stress was alleviated by NaHS, and the percentage of surviving cells increased by 32%. H2S or HS(-), rather than other compounds derived from NaHS, were responsible for promoting 2,4-DCP degradation by P. chrysosporium. The results of this study suggest that H2S treatment is a potential strategy to alleviate environmental stress and improve the efficiency of the biological removal of pollutants from wastewater.
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Nitrite reductase genes as functional markers to investigate diversity of denitrifying bacteria during agricultural waste composting.
Appl. Microbiol. Biotechnol.
PUBLISHED: 01-19-2014
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The purpose of this study was to investigate the diversity of denitrifier community during agricultural waste composting. The diversity and dynamics of the denitrifying genes (nirK and nirS) were determined using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Relationships between physico-chemical parameters and denitrifying genes structures were simultaneously evaluated by redundancy analysis (RDA). Phylogenetic analysis indicated that nirK clones grouped into six clusters and nirS clones into two major clusters, respectively. The results showed a very high diversity of nir gene sequences within composting samples. RDA showed that the nirK and nirS gene structures were significantly related to pH and pile temperature (P?
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Facile green extracellular biosynthesis of CdS quantum dots by white rot fungus Phanerochaete chrysosporium.
Colloids Surf B Biointerfaces
PUBLISHED: 01-14-2014
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This study details a novel method for the extracellular microbial synthesis of cadmium sulfide (CdS) quantum dots (QDs) by the white rot fungus Phanerochaete chrysosporium. P. chrysosporium was incubated in a solution containing cadmium nitrate tetrahydrate, which became yellow from 12h onwards, indicating the formation of CdS nanocrystals. The purified solution showed a maximum absorbance peak between 296 and 298 nm due to CdS particles in the quantum size regime. The fluorescence emission at 458 nm showed the blue fluorescence of the nanoparticles. X-ray analysis of the nanoparticles confirmed the production of CdS with a face-centered cubic (fcc) crystal structure. The average grain size of the nanoparticles was approximately 2.56 nm, as determined from the full width at half-maximum (FWHM) measurement of the most intense peak using Scherer's equation. Transmission electron microscopic analysis showed the nanoparticles to be of a uniform size with good crystallinity. The changes to the functional groups on the biomass surface were investigated through Fourier transform infrared spectroscopy. Furthermore, the secretion of cysteine and proteins was found to play an important role in the formation and stabilization of CdS QDs. In conclusion, our study outlines a chemical process for the molecular synthesis of CdS nanoparticles.
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Effects of limonene stress on the growth of and microcystin release by the freshwater cyanobacterium Microcystis aeruginosa FACHB-905.
Ecotoxicol. Environ. Saf.
PUBLISHED: 01-13-2014
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The effects of limonene exposure on the growth of Microcystisaeruginosa and the release of toxic intracellular microcystin (MCY) were tested by evaluating the results obtained from the batch culture experiments with M. aeruginosa FACHB-905. The time series of cell as well as intracellular and extracellular MCY concentrations were evaluated during 5d of the incubation. After exposure to limonene, the number of cells gradually diminished; the net log cell reduction after 5d of the exposure was 3.0, 3.6, and 3.8log when the initial cell densities were set at 1.6×10(7), 1.1×10(6) and 4.1×10(5)cell/mL, respectively. Limonene was found to significantly influence the production and release of MCY. As the limonene exposure could inhibit the increase in the number of cells, the increase in the total MCY concentration in the medium was also inhibited. In the presence of limonene, the intracellular MCY was gradually released into the medium through a gradual reduction in the number of cells. The extracellular MCY concentration in the medium was significantly higher in the limonene-exposed samples than in the control samples, which confirmed that limonene cannot decompose the extracellular MCY.
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Heavy metal-induced glutathione accumulation and its role in heavy metal detoxification in Phanerochaete chrysosporium.
Appl. Microbiol. Biotechnol.
PUBLISHED: 01-13-2014
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Phanerochaete chrysosporium are known to be vital hyperaccumulation species for heavy metal removal with admirable intracellular bioaccumulation capacity. This study analyzes the heavy metal-induced glutathione (GSH) accumulation and the regulation at the intracellular heavy metal level in P. chrysosporium. P. chrysosporium accumulated high levels of GSH, accompanied with high intracellular concentrations of Pb and Cd. Pb bioaccumulation lead to a narrow range of fluctuation in GSH accumulation (0.72-0.84 ?mol), while GSH plummeted under Cd exposure at the maximum value of 0.37 ?mol. Good correlations between time-course GSH depletion and Cd bioaccumulation were determined (R (2) > 0.87), while no significant correlations have been found between GSH variation and Pb bioaccumulation (R (2) < 0.38). Significantly, concentration-dependent molar ratios of Pb/GSH ranging from 0.10 to 0.18 were observed, while molar ratios of Cd/GSH were at the scope of 1.53-3.32, confirming the dominant role of GSH in Cd chelation. The study also demonstrated that P. chrysosporium showed considerable hypertolerance to Pb ions, accompanied with demand-driven stimulation in GSH synthesis and unconspicuous generation of reactive oxygen stress. GSH plummeted dramatically response to Cd exposure, due to the strong affinity of GSH to Cd and the involvement of GSH in Cd detoxification mechanism mainly as Cd chelators. Investigations into GSH metabolism and its role in ameliorating metal toxicity can offer important information on the application of the microorganism for wastewater treatment.
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Pilon: An Integrated Tool for Comprehensive Microbial Variant Detection and Genome Assembly Improvement.
PLoS ONE
PUBLISHED: 01-01-2014
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Advances in modern sequencing technologies allow us to generate sufficient data to analyze hundreds of bacterial genomes from a single machine in a single day. This potential for sequencing massive numbers of genomes calls for fully automated methods to produce high-quality assemblies and variant calls. We introduce Pilon, a fully automated, all-in-one tool for correcting draft assemblies and calling sequence variants of multiple sizes, including very large insertions and deletions. Pilon works with many types of sequence data, but is particularly strong when supplied with paired end data from two Illumina libraries with small e.g., 180 bp and large e.g., 3-5 Kb inserts. Pilon significantly improves draft genome assemblies by correcting bases, fixing mis-assemblies and filling gaps. For both haploid and diploid genomes, Pilon produces more contiguous genomes with fewer errors, enabling identification of more biologically relevant genes. Furthermore, Pilon identifies small variants with high accuracy as compared to state-of-the-art tools and is unique in its ability to accurately identify large sequence variants including duplications and resolve large insertions. Pilon is being used to improve the assemblies of thousands of new genomes and to identify variants from thousands of clinically relevant bacterial strains. Pilon is freely available as open source software.
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Antibody recognition of Shiga toxins (Stxs): computational identification of the epitopes of Stx2 subunit A to the antibodies 11E10 and S2C4.
PLoS ONE
PUBLISHED: 01-01-2014
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We have recently developed a new method to predict the epitopes of the antigens that are recognized by a specific antibody. In this work, we applied the method to identify the epitopes of the Shiga toxin (Stx2 subunit A) that were bound by two specific antibodies 11E10 and S2C4. The predicted epitopes of Stx2 binding to the antibody 11E10 resembles the recognition surface constructed by the regions of Stx2 identified experimentally. For the S2C4, our results indicate that the antibody recognizes the Stx2 at two different regions on the protein surface. The first region (residues 246-254: ARSVRAVNE) is similar to the recognition region of the 11E10, while the second region is formed by two epitopes. The second region is particularly significant because it includes the amino acid sequence region that is diverse between Stx2 and other Stx (residues 176-188: QREFRQALSETAPV). This new recognition region is believed to play an important role in the experimentally observed selectivity of S2C4 to the Stx2.
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High-Quality Draft Genome Sequence of Vagococcus lutrae Strain LBD1, Isolated from the Largemouth Bass Micropterus salmoides.
Genome Announc
PUBLISHED: 12-28-2013
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Vagococci are usually isolated from marine hosts and occasionally from endodontic infections. Using 16S rRNA gene comparison, the closest relatives are members of the genera Enterococcus and Carnobacterium. A draft sequence of Vagococcus lutrae was generated to clarify the relationship of Vagococcus to these and other related low-G+C Gram-positive bacteria.
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Plasmonic interferometric sensor arrays for high-performance label-free biomolecular detection.
Lab Chip
PUBLISHED: 11-01-2013
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A plasmonic interferometric biosensor that consists of arrays of circular aperture-groove nanostructures patterned on a gold film for phase-sensitive biomolecular detection is demonstrated. The phase and amplitude of interfering surface plasmon polaritons (SPPs) in the proposed device can be effectively engineered by structural tuning, providing flexible and efficient control over the plasmon line shape observed through SPP interference. Spectral fringes with high contrast, narrow linewidth, and large amplitude have been experimentally measured and permit the sensitive detection of protein surface coverage as low as 0.4 pg mm(-2). This sensor resolution compares favorably with commercial prism-based surface plasmon resonance systems (0.1 pg mm(-2)) but is achieved here using a significantly simpler collinear transmission geometry, a miniaturized sensor footprint, and a low-cost compact spectrometer. Furthermore, we also demonstrate superior sensor performance using the intensity interrogation method, which can be combined with CCD imaging to upscale our platform to high-throughput array sensing. A novel low-background interferometric sensing scheme yields a high sensing figure of merit (FOM*) of 146 in the visible region, surpassing that of previous plasmonic biosensors and facilitating ultrasensitive high-throughput detection.
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Adsorption characteristics of Cu and Zn onto various size fractions of aggregates from red paddy soil.
J. Hazard. Mater.
PUBLISHED: 09-02-2013
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Soil aggregate is the basic structure unit of soils and the ability of various size fractions are different in the aspect of adsorbing and transferring heavy metals in the environment. In this study, bulk soil from red paddy field was partitioned into four aggregate-size fractions and their adsorption characteristics for Cu and Zn were studied. Our results showed that: Pseudo-second order model was more successful to fit the adsorption process in the kinetic experiments and the isothermal experiments data can be described well with the Freundlich model as a whole. Due to higher contents in organic matter, CEC and free iron oxide, the <0.002mm fraction was found to have the highest initial sorption rate and maximum adsorption capacity. The adsorption amount of metals increased as the increasing of pH and the percentage of adsorbed metal susceptible to desorption into 0.01M NaNO3 was greater for Zn than for Cu, while their variation trends were quite opposite. More specific adsorption sites in the <0.002mm fraction lead to more desorption amount for this particle size of soil at low pH condition. After 60 days of incubation, Cu and Zn were observed to enrich in the clay-size aggregates with fractions more stable than other particles.
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Emergence of epidemic multidrug-resistant Enterococcus faecium from animal and commensal strains.
MBio
PUBLISHED: 08-22-2013
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Enterococcus faecium, natively a gut commensal organism, emerged as a leading cause of multidrug-resistant hospital-acquired infection in the 1980s. As the living record of its adaptation to changes in habitat, we sequenced the genomes of 51 strains, isolated from various ecological environments, to understand how E. faecium emerged as a leading hospital pathogen. Because of the scale and diversity of the sampled strains, we were able to resolve the lineage responsible for epidemic, multidrug-resistant human infection from other strains and to measure the evolutionary distances between groups. We found that the epidemic hospital-adapted lineage is rapidly evolving and emerged approximately 75 years ago, concomitant with the introduction of antibiotics, from a population that included the majority of animal strains, and not from human commensal lines. We further found that the lineage that included most strains of animal origin diverged from the main human commensal line approximately 3,000 years ago, a time that corresponds to increasing urbanization of humans, development of hygienic practices, and domestication of animals, which we speculate contributed to their ecological separation. Each bifurcation was accompanied by the acquisition of new metabolic capabilities and colonization traits on mobile elements and the loss of function and genome remodeling associated with mobile element insertion and movement. As a result, diversity within the species, in terms of sequence divergence as well as gene content, spans a range usually associated with speciation.
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Kinannote, a computer program to identify and classify members of the eukaryotic protein kinase superfamily.
Bioinformatics
PUBLISHED: 07-31-2013
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Kinases of the eukaryotic protein kinase superfamily are key regulators of most aspects eukaryotic cellular behavior and have provided several drug targets including kinases dysregulated in cancers. The rapid increase in the number of genomic sequences has created an acute need to identify and classify members of this important class of enzymes efficiently and accurately.
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Human antibody neutralizes severe Fever with thrombocytopenia syndrome virus, an emerging hemorrhagic Fever virus.
Clin. Vaccine Immunol.
PUBLISHED: 07-17-2013
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Severe fever with thrombocytopenia syndrome virus (SFTSV), a newly discovered member of the Bunyaviridae family, is the causative agent of an emerging hemorrhagic fever, SFTS, in China. Currently, there are no vaccines or effective therapies against SFTS. In this study, a combinatorial human antibody library was constructed from the peripheral lymphocytes of 5 patients who had recovered from SFTS. The library was screened against purified virions for the production of single-chain variable-region fragments (ScFv). Of the 6 positive clones, one clone (monoclonal antibody [MAb] 4-5) showed neutralizing activity against SFTSV infection in Vero cells. MAb 4-5 was found to effectively neutralize all of the clinical isolates of SFTSV tested, which were isolated from patients in China from 2010 to 2012. MAb 4-5 was found to bind a linear epitope in the ectodomain of glycoprotein Gn. Its neutralizing activity is attributed to blockage of the interactions between the Gn protein and the cellular receptor, indicating that inhibition of virus-cell attachment is its main mechanism. These data suggest that MAb 4-5 can be used as a promising candidate molecule for immunotherapy against SFTSV infection.
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Experimental study on a room temperature urea-SCR of NO over activated carbon fibre-supported CeO2-CuO.
Environ Technol
PUBLISHED: 07-11-2013
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In order to establish a desirable method for NO reduction, selective catalytic reduction (SCR) of NO by urea-CeO2/ACF and urea-CeO2-CuO/ACF was carried out at room temperature. The experimental results showed that 10% urea-9% CeO2/ACF could yield the highest NO conversion of 85% among the series of urea-CeO2/ACF prepared. When urea-CeO2-CuO/ACF was compared with urea-CeO2/ACF, it achieved higher NO conversion to a certain degree with the addition of CuO, which was attributed to the synergistic effect between cerium and copper. The effect of the mass ratio of CeO2 and CuO was also observed. The desirable mass ratio of CeO2 and CuO was 1:1, which yielded about 90% NO conversion when ACF was loaded with 10% urea. Furthermore, the influence of O2 concentration and NO concentration was also observed. In this study, NO conversion increased with increasing O2 concentration. In addition, some samples were further characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared methods.
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The adsorption behavior and mechanism investigation of Pb(II) removal by flocculation using microbial flocculant GA1.
Bioresour. Technol.
PUBLISHED: 06-26-2013
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In this work, microbial flocculant GA1 (MBFGA1) was used to remove Pb(II) ions from aqueous solution. A series of experimental parameters including initial pH, MBFGA1 dose, temperature and initial calcium ions concentration on Pb(II) uptake was evaluated. Meanwhile, the flocculation mechanism of MBFGA1 was investigated. The removal efficiency of Pb(II) reached up to 99.85% when MBFGA1 was added in two stages, separately. The results indicated that Pb(II) adsorption could be described by the Langmuir adsorption model, and being the monolayer capacity negatively affected with an increase in temperature. The adsorption process could be described by pseudo-second-order kinetic model. Fourier transform-infrared spectra and environmental scanning electron microscope analysis indicated that MBFGA1 had a large number of functional groups, which had strong capacity for removing Pb(II). The main mechanisms of Pb(II) removal by MBFGA1 could be charge neutralization and adsorption bridging.
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Inhibitory effects of sanguinarine against the cyanobacterium Microcystis aeruginosa NIES-843 and possible mechanisms of action.
Aquat. Toxicol.
PUBLISHED: 06-26-2013
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Sanguinarine showed strong inhibitory effect against Microcystis aeruginosa, a typical water bloom-forming and microcystins-producing cyanobacterium. The EC50 of sanguinarine against the growth of M. aeruginosa NIES-843 was 34.54±1.17 ?g/L. Results of chlorophyll fluorescence transient analysis indicated that all the electron donating side, accepting side, and the reaction center of the Photosystem II (PS II) were the targets of sanguinarine against M. aeruginosa NIES-843. The elevation of reactive oxygen species (ROS) level in the cells of M. aeruginosa NIES-843 upon exposure indicated that sanguinarine induced oxidative stress in the active growing cells of M. aeruginosa NIES-843. Further results of gene expression analysis indicated that DNA damage and cell division inhibition were also involved in the inhibitory action mechanism of sanguinarine against M. aeruginosa NIES-843. The inhibitory characteristics of sanguinarine against M. aeruginosa suggest that the ecological- and public health-risks need to be evaluated before its application in cyanobacterial bloom control to avoid devastating events irreversibly.
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Computational identification of epitopes in the glycoproteins of novel bunyavirus (SFTS virus) recognized by a human monoclonal antibody (MAb 4-5).
J. Comput. Aided Mol. Des.
PUBLISHED: 06-24-2013
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In this work, we have developed a new approach to predict the epitopes of antigens that are recognized by a specific antibody. Our method is based on the "multiple copy simultaneous search" (MCSS) approach which identifies optimal locations of small chemical functional groups on the surfaces of the antibody, and identifying sequence patterns of peptides that can bind to the surface of the antibody. The identified sequence patterns are then used to search the amino-acid sequence of the antigen protein. The approach was validated by reproducing the binding epitope of HIV gp120 envelop glycoprotein for the human neutralizing antibody as revealed in the available crystal structure. Our method was then applied to predict the epitopes of two glycoproteins of a newly discovered bunyavirus recognized by an antibody named MAb 4-5. These predicted epitopes can be verified by experimental methods. We also discuss the involvement of different amino acids in the antigen-antibody recognition based on the distributions of MCSS minima of different functional groups.
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Distinctive expansion of potential virulence genes in the genome of the oomycete fish pathogen Saprolegnia parasitica.
PLoS Genet.
PUBLISHED: 06-01-2013
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Oomycetes in the class Saprolegniomycetidae of the Eukaryotic kingdom Stramenopila have evolved as severe pathogens of amphibians, crustaceans, fish and insects, resulting in major losses in aquaculture and damage to aquatic ecosystems. We have sequenced the 63 Mb genome of the fresh water fish pathogen, Saprolegnia parasitica. Approximately 1/3 of the assembled genome exhibits loss of heterozygosity, indicating an efficient mechanism for revealing new variation. Comparison of S. parasitica with plant pathogenic oomycetes suggests that during evolution the host cellular environment has driven distinct patterns of gene expansion and loss in the genomes of plant and animal pathogens. S. parasitica possesses one of the largest repertoires of proteases (270) among eukaryotes that are deployed in waves at different points during infection as determined from RNA-Seq data. In contrast, despite being capable of living saprotrophically, parasitism has led to loss of inorganic nitrogen and sulfur assimilation pathways, strikingly similar to losses in obligate plant pathogenic oomycetes and fungi. The large gene families that are hallmarks of plant pathogenic oomycetes such as Phytophthora appear to be lacking in S. parasitica, including those encoding RXLR effectors, Crinklers, and Necrosis Inducing-Like Proteins (NLP). S. parasitica also has a very large kinome of 543 kinases, 10% of which is induced upon infection. Moreover, S. parasitica encodes several genes typical of animals or animal-pathogens and lacking from other oomycetes, including disintegrins and galactose-binding lectins, whose expression and evolutionary origins implicate horizontal gene transfer in the evolution of animal pathogenesis in S. parasitica.
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Ultrathin nanostructured metals for highly transmissive plasmonic subtractive color filters.
Sci Rep
PUBLISHED: 05-28-2013
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Plasmonic color filters employing a single optically-thick nanostructured metal layer have recently generated considerable interest as an alternative to colorant-based color filtering technologies, due to their reliability, ease of fabrication, and high color tunability. However, their relatively low transmission efficiency (~30%) needs to be significantly improved for practical applications. The present work reports, for the first time, a novel plasmonic subtractive color filtering scheme that exploits the counter-intuitive phenomenon of extraordinary low transmission (ELT) through an ultrathin nanostructured metal film. This approach relies on a fundamentally different color filtering mechanism than that of existing plasmonic additive color filters, and achieves unusually high transmission efficiencies of 60 ~ 70% for simple architectures. Furthermore, owing to short-range interactions of surface plasmon polaritons at ELT resonances, our design offers high spatial resolution color filtering with compact pixel size close to the optical diffraction limit (~?/2), creating solid applications ranging from imaging sensors to color displays.
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Recent development in the treatment of oily sludge from petroleum industry: a review.
J. Hazard. Mater.
PUBLISHED: 05-21-2013
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Oily sludge is one of the most significant solid wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. In this review, the origin, characteristics, and environmental impacts of oily sludge were introduced. Many methods have been investigated for dealing with PHCs in oily sludge either through oil recovery or sludge disposal, but little attention has been paid to handle its various heavy metals. These methods were discussed by dividing them into oil recovery and sludge disposal approaches. It was recognized that no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Future efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The comprehensive examination of oily sludge treatment methods will help researchers and practitioners to have a good understanding of both recent developments and future research directions.
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Effects of surfactant and Zn (II) at various concentrations on microbial activity and ethylbenzene removal in biotricking filter.
Chemosphere
PUBLISHED: 05-20-2013
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The effects of Tween-20, a non-ionic surfactant, and Zn (II) on microbial activity and removal performance for ethylbenzene in a biotrickling filter (BTF) were evaluated. Batch experiments were conducted to evaluate the surfactant and Zn (II) at various concentrations for their toxicity to microorganisms, and results indicated that Tween-20 was beneficial to microbial activity at all the tested concentration, while Zn (II) affected adversely when the concentration overpassed 5.0mgL(-1). Then effects of the two additives on removal efficiency of ethylbenzene were evaluated in a BTF at an empty-bed retention time of 30s and an ethylbenzene concentration of 1100mgm(-3). Results showed that the optimal concentrations of Tween-20 and Zn (II) were about 12 and 1.0mgL(-1), respectively. Compared to the results when neither of the two additives was added, Tween-20 improved ethylbenzene removal efficiency from 67% to 86% at the optimal condition, while on that basis, Zn (II) just increased the removal efficiency from 86% to 90%. The promoting effects of the two additives on recovering microbial activity and removing excessive biomass were also observed in this article.
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A tyrosinase biosensor based on ordered mesoporous carbon-Au/L-lysine/Au nanoparticles for simultaneous determination of hydroquinone and catechol.
Analyst
PUBLISHED: 05-13-2013
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A novel biosensor was developed based on tyrosinase immobilization with ordered mesoporous carbon-Au (OMC-Au), L-lysine membrane and Au nanoparticles on a glassy carbon electrode (GCE). It was applied for the simultaneous determination of dihydroxybenzene isomers using differential pulse voltammetry (DPV). The tyrosinase/OMC-Au/L-lysine/Au film was characterized by scanning electron microscopy (SEM) and impedance spectra. Under optimized conditions, the DPV study results for two isomers, hydroquinone (HQ, 1,4-dihydroxybenzene) and catechol (CC, 1,2-dihydroxybenzene) showed low peak potentials, and the peak-to-peak difference was about 135.85 mV, which ensured the anti-interference ability of the biosensor and made simultaneous detection of dihydroxybenzene isomers possible in real samples. DPV peak currents increased linearly with concentration over the range of 4.0 × 10(-7) to 8.0 × 10(-5) M, and the detection limits of hydroquinone and catechol were 5 × 10(-8) M and 2.5 × 10(-8) M (S/N = 3), respectively. The tyrosinase biosensor exhibited good repeatability and stability. In addition, the response mechanism of enzyme catalysed redox on the OMC-Au/L-lysine/Au film modified electrode based on electrochemical study was discussed. The proposed method could be extended for the development of other enzyme-based biosensors.
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La-EDTA coated Fe3O4 nanomaterial: preparation and application in removal of phosphate from water.
J Environ Sci (China)
PUBLISHED: 04-20-2013
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La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4, and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.
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Statin therapy improves response to interferon alfa and ribavirin in chronic hepatitis C: a systematic review and meta-analysis.
Antiviral Res.
PUBLISHED: 04-07-2013
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The treatment of interferon alfa (IFN-?) and ribavirin for chronic hepatitis C virus (HCV) infection achieves limited sustained virological response (SVR). We conducted a systematic review and meta-analysis to explore the efficacy of adding statins to IFN-? and ribavirin therapy for chronic hepatitis C. Studies with data pertinent to the effect of statins on chronic hepatitis C were reviewed, and randomized controlled trials (RCTs) evaluating the efficacy of the addition of statins to IFN-? and ribavirin were included in meta-analysis. The primary outcome measure was SVR. Secondary outcome measures were rapid virological response (RVR) and early virological response (EVR). The literature was systematically searched through October 2012. After screening of the 1724 non-duplicated entries, 54 potentially relevant studies were fully reviewed. Of those, 18 studies were relevant and 5 RCTs met the inclusion criteria for meta-analysis. In comparison with IFN-? and ribavirin therapy, the addition of statins significantly increased SVR (OR=2.02, 95% CI: 1.38-2.94), RVR (OR=3.51, 95% CI: 1.08-11.42) and EVR (OR=1.89, 95% CI: 1.20-2.98). The SVR increase remained significant for HCV genotype 1 (OR=2.11, 95% CI: 1.40-3.18). There were no significant increases in adverse events and withdrawals with the addition of statins. In conclusion, the addition of statins to IFN-? and ribavirin improves SVR, RVR, and EVR without additional adverse events and thus may be considered as adjuvant to IFN-? and ribavirin for chronic hepatitis C. Statins might also be used for HCV genotypes other than genotype 1, or in patients in whom the use of protease inhibitors is contraindicated or not indicated.
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Highly sensitive strategy for Hg2+ detection in environmental water samples using long lifetime fluorescence quantum dots and gold nanoparticles.
Environ. Sci. Technol.
PUBLISHED: 04-03-2013
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The authors herein described a time-gated fluorescence resonance energy transfer (TGFRET) sensing strategy employing water-soluble long lifetime fluorescence quantum dots and gold nanoparticles to detect trace Hg(2+) ions in aqueous solution. The water-soluble long lifetime fluorescence quantum dots and gold nanoparticles were functionalized by two complementary ssDNA, except for four deliberately designed T-T mismatches. The quantum dot acted as the energy-transfer donor, and the gold nanoparticle acted as the energy-transfer acceptor. When Hg(2+) ions were present in the aqueous solution, DNA hybridization will occur because of the formation of T-Hg(2+)-T complexes. As a result, the quantum dots and gold nanoparticles are brought into close proximity, which made the energy transfer occur from quantum dots to gold nanoparticles, leading to the fluorescence intensity of quantum dots to decrease obviously. The decrement fluorescence intensity is proportional to the concentration of Hg(2+) ions. Under the optimum conditions, the sensing system exhibits the same liner range from 1 × 10(-9) to 1 × 10(-8) M for Hg(2+) ions, with the detection limits of 0.49 nM in buffer and 0.87 nM in tap water samples. This sensor was also used to detect Hg(2+) ions from samples of tap water, river water, and lake water spiked with Hg(2+) ions, and the results showed good agreement with the found values determined by an atomic fluorescence spectrometer. In comparison to some reported colorimetric and fluorescent sensors, the proposed method displays the advantage of higher sensitivity. The TGFRET sensor also exhibits excellent selectivity and can provide promising potential for Hg(2+) ion detection.
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Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.
Bioresour. Technol.
PUBLISHED: 03-29-2013
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Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3.
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