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Dye removal of AR27 with enhanced degradation and power generation in a microbial fuel cell using bioanode of treated clinoptilolite-modified graphite felt 全文
2017
Kardi, Seyedeh Nazanin | Ibrahim, Norahim | Najafpour-Darzi, Ghasem | Rashid, Noor Aini Abdul | Villaseñor, José
This work studied the performance of a laboratory-scale microbial fuel cell (MFC) using a bioanode that consisted of treated clinoptilolite fine powder coated onto graphite felt (TC-MGF). The results were compared with another similar MFC that used a bare graphite felt (BGF) bioanode. The anode surfaces provided active sites for the adhesion of the bacterial consortium (NAR-2) and the biodegradation of mono azo dye C.I. Acid Red 27. As a result, bioelectricity was generated in both MFCs. A 98% decolourisation rate was achieved using the TC-MGF bioanode under a fed-batch operation mode. Maximum power densities for BGF and TC-MGF bioanodes were 458.8 ± 5.0 and 940.3 ± 4.2 mW m⁻², respectively. GC-MS analyses showed that the dye was readily degraded in the presence of the TC-MGF bioanode. The MFC using the TC-MGF bioanode showed a stable biofilm with no biomass leached out for more than 300 h operation. In general, MFC performance was substantially improved by the fabricated TC-MGF bioanode. It was also found that the TC-MGF bioanode with the stable biofilm presented the nature of exopolysaccharide (EPS) structure, which is suitable for the biodegradation of the azo dye. In fact, the EPS facilitated the shuttling of electrons to the bioanode for the generation of bioelectricity.
显示更多 [+] 显示较少 [-]Toxic effect of nonylphenol on the marine macroalgae Gracilaria lemaneiformis (Gracilariales, Rhodophyta): antioxidant system and antitumor activity 全文
2017
Zhong, Mingqin | Yin, Pinghe | Zhao, Ling
The objective of the present work was to evaluate the toxic effect of nonylphenol (NP) on the antioxidant response and antitumor activity of Gracilaria lemaneiformis. An obvious oxidative damage was observed in this study. The thallus exposed to NP showed 1.2–2.0-fold increase in lipid peroxide and displayed a maximum level of 16.58 μmol g⁻¹ Fw on 0.6 mg L⁻¹ for 15-day exposure. The activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) enhanced significantly by 1.1–3.2-fold and subsequently diminished at the high concentrations and prolonged exposure. The results of DNA damage in comet assay also supported that NP was obviously toxic on G. lemaneiformis with increasing the percentage of tail DNA in a dose-dependent manner. Furthermore, the ethanol extract of G. lemaneiformis (EEGL) did exhibit antitumor potential against HepG-2 cells. While decreased in cell inhibition, ROS generation, apoptosis, and caspase-3 in HepG-2 cells treated with the EEGL were observed when G. lemaneiformis was exposed to NP for 15 days, and which were related to exposure concentration of NP. These suggested that NP has strongly toxic effect on the antitumor activity of G. lemaneiformis. The results revealed in this study imply that macroalgae can be useful biomarkers to evaluate marine pollutions.
显示更多 [+] 显示较少 [-]Atmospheric deposition of PBDEs and DPs in Dongjiang River Basin, South China 全文
2017
Wu, Xiaowei | Wang, Yan | Hou, Minmin | Luo, Chunling | Zhao, Hongxia | Zhang, Gan
The atmospheric deposition fluxes of polybrominated diphenyl ethers (PBDEs) and Dechlorane Plus (DPs) in Dongjiang River Basin of the Pearl River Delta in South China were investigated during winter and summer, respectively. The total deposition fluxes varied from 4.74 to 27.0 ng/m²/day for PBDEs and 8.77 to 206 ng/m²/day for DPs, respectively. The fractions of anti-DP to the total DPs (f ₐₙₜᵢ) varied from 0.28 to 0.63 (mean = 0.43 ± 0.06), i.e., generally lower than those in commercial products, which might be attributed to the different environmental fates of the two isomers. Significant seasonal and spatial variations of PBDEs and DPs were observed. The deposition fluxes in summer were generally higher than those in winter, which may be due to the relatively high temperature and rainfall in summer under the influence of prevailing subtropical monsoon climate. Moreover, high deposition fluxes of PBDEs and DPs in urban areas and significant urban/rural gradient implied that local industrial activities in the urban areas were primary sources, which were further confirmed by the results of principal component analysis. The highest deposition of PBDE and DP fluxes was found at different sampling sites, suggesting PBDEs and DPs may be derived from different industries or products.
显示更多 [+] 显示较少 [-]Ecotoxicity evaluation of a WWTP effluent treated by solar photo-Fenton at neutral pH in a raceway pond reactor 全文
2017
Freitas, A. M. | Rivas, G. | Campos-Mañas, M. C. | Casas López, J. L. | Agüera, A. | Sánchez Pérez, J. A.
Some pollutants can be resistant to wastewater treatment, hence becoming a risk to aquatic and terrestrial biota even at the very low concentrations (ng L⁻¹–μg L⁻¹) they are commonly found at. Tertiary treatments are used for micropollutant removal but little is known about the ecotoxicity of the treated effluent. In this study, a municipal secondary effluent was treated by a solar photo-Fenton reactor at initial neutral pH in a raceway pond reactor, and ecotoxicity was evaluated before and after micropollutant removal. Thirty-nine micropollutants were identified in the secondary effluent, mainly pharmaceuticals, with a total concentration of ≈80 μg L⁻¹. After treatment, 99 % microcontaminant degradation was reached. As for ecotoxicity reduction, the assayed organisms showed the following sensitivity levels: Tetrahymena thermophila > Daphnia magna > Lactuca sativa > Spirodela polyrhiza ≈ Vibrio fischeri. The initial effluent showed an inhibitory effect of 40 % for T. thermophila and 20 % for D. magna. After 20 min of photo-Fenton treatment, no toxic effect was observed for T. thermophila and toxicity dropped to 5 % for D. magna. Graphical abstract Ecotoxicity removal by solar photo-Fenton at neutral pH. ᅟ
显示更多 [+] 显示较少 [-]Modifications of the chemical structure of phenolics differentially affect physiological activities in pulvinar cells of Mimosa pudica L. II. Influence of various molecular properties in relation to membrane transport 全文
2017
Rocher, Françoise | Roblin, Gabriel | Chollet, Jean-François
Early prediction of compound absorption by cells is of considerable importance in the building of an integrated scheme describing the impact of a compound on intracellular biological processes. In this scope, we study the structure-activity relationships of several benzoic acid-related phenolics which are involved in many plant biological phenomena (growth, flowering, allelopathy, defense processes). Using the partial least squares (PLS) regression method, the impact of molecular descriptors that have been shown to play an important role concerning the uptake of pharmacologically active compounds by animal cells was analyzed in terms of the modification of membrane potential, variations in proton flux, and inhibition of the osmocontractile reaction of pulvinar cells of Mimosa pudica leaves. The hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA), polar surface area (PSA), halogen ratio (Hal ratio), number of rotatable bonds (FRB), molar volume (MV), molecular weight (MW), and molar refractivity (MR) were considered in addition to two physicochemical properties (logD and the amount of non-dissociated form in relation to pKa). HBD + HBA and PSA predominantly impacted the three biological processes compared to the other descriptors. The coefficient of determination in the quantitative structure-activity relationship (QSAR) models indicated that a major part of the observed seismonasty inhibition and proton flux modification can be explained by the impact of these descriptors, whereas this was not the case for membrane potential variations. These results indicate that the transmembrane transport of the compounds is a predominant component. An increasing number of implicated descriptors as the biological processes become more complex may reflect their impacts on an increasing number of sites in the cell. The determination of the most efficient effectors may lead to a practical use to improve drugs in the control of microbial attacks on plants.
显示更多 [+] 显示较少 [-]Investigation of diethylstilbestrol residue level in human urine samples by a specific monoclonal antibody 全文
2017
Zhang, Dai | Zhou, Lifang | Lei, Yajing | Zhou, Zhan | Zhou, Jie | Chen, Shuqing
Diethylstilbestrol (DES) is used as a kind of animal feed additive and affects people’s health through the food chain. The purpose of this study is to detect the residue level of DES in 576 human urine samples directly. DES-BSA was used to immunize Balb/c mice. The monoclonal antibody was produced by hybridoma that was screened through cell fusion techniques. Finally, we developed the indirect competitive ELISA method to analyze 576 human urine samples from Zhejiang Province, China. The IC₅₀ of this method was 3.33 ng/mL. The LOD and LOQ were 0.16 and 0.54 ng/mL. Linear range of the standard curve was from LOD to 12.50 ng/mL. There was no cross-reactivity with two kinds of estrogens and two structural analogs with DES. Five hundred seventy-six urine samples were analyzed by the indirect competitive ELISA method, and the detection rate was 98.78%. The mean concentration and geometric mean were 4.70 and 3.50 ng/mL. The indirect competitive ELISA method based on monoclonal antibody was sensitive and reliable for the detection of DES in human urine samples. The results warned us to pay more attention to human health and food safety.
显示更多 [+] 显示较少 [-]Bioprospecting hot spring metagenome: lipase for the production of biodiesel 全文
2017
Sahoo, Rajesh Kumar | Mohit, Kumar | Sukla, Lala Behari | Subudhi, Enketeswara
Screening of metagenomic library from Taptapani Hot Spring (Odisha) yielded a positive lipase clone (pUC-lip479). Sequence analysis showed an ORF (RK-lip479) of 416 amino acid residues which was overexpressed in Escherichia coli BL21 (DE3). Optimum pH and temperature of purified lipase RK-lip479 were 8.0 and 65 °C, respectively, and found to be stable over a pH range of 7.0–9.0 and temperatures 55–75 °C. RK-lip479 could hydrolyse a wide range of 4-nitrophenyl esters (4-nitrophenyoctanoate, 4-nitrophenyldodecanoate, 4-nitrophenylpalmitate, 4-nitrophenylmyristate and 4-nitrophenylstearate), and maximum activity was observed with 4-nitrophenyldodecanoate. RK-lip479 was resistant to many organic solvents, especially isopropanol, DMSO, methanol, DMF, ethanol, dichloromethane, acetone, glycerol and ethyl acetate. RK-lip479 also showed activity in the presence of monovalent (Na⁺ and K⁺), divalent (Mg²⁺, Mn²⁺, Ca²⁺, Hg²⁺, Cu²⁺, Co²⁺, Zn²⁺ and Ag²⁺) and trivalent cations (Fe³⁺ and Al³⁺). Yield of biodiesel production was in the range of 40–76% using various waste oils with RK-Lip479 under optimized conditions.
显示更多 [+] 显示较少 [-]Biosurfactant production by the crude oil degrading Stenotrophomonas sp. B-2: chemical characterization, biological activities and environmental applications 全文
2017
Gargouri, Boutheina | Contreras, María del Mar | Ammar, Sonda | Segura-Carretero, Antonio | Bouaziz, Mohamed
In this work, biosurfactant-producing microorganisms were isolated from hydrocarbon-contaminated water collected from Tunisian oilfield. After enrichment and isolation, different bacterial strains were preliminary studied for their biosurfactant/bioemulsifier properties when using crude oil as the unique carbon source. In particular, the isolate strain B-2, a Gram-negative, rod-shaped bacterium, efficiently emulsified crude oil. The extracellular biosurfactant product from this strain presented an emulsification activity above 70% and a hydrophobicity of 71%. In addition, a diameter of 6 cm was observed in the oil displacement test. The characterization of B-2 strain using 16S rDNA sequencing enables us to find a high degree of similarity with various members of the genus Stenotrophomonas (with a percentage of similarity of 99%). The emulsification activity of Stenotrophomonas biosurfactant B-2 was maintained in a wide range of pH (2 to 6), temperature (4 to 55 °C), and salinity (0 to 50 g L⁻¹) conditions. It also enhanced the solubility of phenanthrene in water and could be used in the re-mobilization of hydrocarbon-contaminated environment. In addition, this biosurfactant exhibited antimicrobial and antioxidant properties. Infrared spectroscopy suggested potential lipidic and peptidic moieties, and mass spectrometry-based analyses showed that the biosurfactant contains mainly cyclic peptidic structures belonging to the class of diketopiperazines. Therefore, the B-2 strain is a promising biosurfactant-producing microorganism and its derived biosurfactant presents a wide range of industrial applications.
显示更多 [+] 显示较少 [-]Investigation of selenium pretreatment in the attenuation of lung injury in rats induced by fine particulate matters 全文
2017
Liu, Jie | Yang, Yingying | Zeng, Xuejiao | Bo, Liang | Jiang, Shuo | Du, Xihao | Xie, Yuquan | Jiang, Rongfang | Zhao, Jinzhuo | Song, Weimin
Selenium (Se) is vital for health because of its antioxidative and anti-inflammation functions. The aim of this study was to determine if dietary selenium could inhibit the rat lung injury induced by ambient fine particulate matter (PM₂.₅). Sprague-Dawley rats were randomly allocated in seven groups (n = 8). The rats in PM₂.₅ exposure group were intratracheally instilled with 40 mg/kg of body weight (b.w.) of PM₂.₅ suspension. The rats in Se prevention groups were pretreated with 17.5, 35, or 70 μg/kg b.w. of Se for 4 weeks, respectively. Then, the rats were exposed to 40 mg/kg b.w. of PM₂.₅ in the fifth week. The bronchoalveolar lavage fluid (BALF) was collected to count the neutrophil numbers and to analyze the cytokines (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), soluble intercellular adhesion molecule-1 (sICAM-1)) related to inflammation, the markers related to oxidative stress (total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA)), and the indicators related to cell damage (lactate dehydrogenase (LDH), total protein (TP), alkaline phosphatase (AKP)). The lung lobe that has not undergone bronchoalveolar lavage was processed for light microscopic examination. The results showed that the proportions of neutrophils in the BALF and the pathologic scores of the lung in PM₂.₅-exposed groups were higher than that in the control group (P < 0.05). Se pretreatment caused a dose-dependent decrease in TNF-α, IL-1β, sICAM-1, LDH, TP, AKP, and MDA when compared with the PM₂.₅-only exposure group. Meanwhile, the dose-dependent increase in T-AOC, T-SOD, and GSH-Px activities were observed in rats pretreated with Se. In conclusion, Se pretreatment may protect rat lungs against inflammation and oxidative stress induced by PM₂.₅, which suggests that Se plays an important role as a kind of potential preventative agent to inhibit the PM₂.₅-induced lung injury.
显示更多 [+] 显示较少 [-]Aquatic environmental assessment of Lake Balaton in the light of physical-chemical water parameters 全文
2017
Sebestyén, Vitkor | Németh, József | Juzsakova, Tatjana | Domokos, Endre | Kovács, Zsófia | Rédey, Ákos
One of the issues of the Hungarian Water Management Strategy is the improvement and upgrading of the water of Lake Balaton. The Water Framework Directive (WFD) specifies and sets forth the achievement of the good ecological status. However, the assessment of the water quality of the lake as a complex system requires a comprehensive monitoring and evaluation procedure. Measurements were carried out around the Lake Balaton at ten different locations/sites and 13 physical-chemical parameters were monitored at each measurement site.For the interpretation of the water chemistry parameters the Aquatic Environmental Assessment (AEA) method devised by authors was used for the water body of the Lake Balaton. The AEA method can be used for all types of the water bodies since it is flexible and using individual weighting procedure for the water chemistry parameters comprehensive information can be obtain. The AEA method was compared with existing EIA methods according to a predefined criterion system and proved to be the most suitable tool for evaluating the environmental impacts in our study.On the basis of the results it can be concluded that the status of the quality of studied area on the Lake Balaton can be categorized as proper quality (from the outcome of the ten measurement sites this conclusion was reached at seven sites).
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