خيارات البحث
النتائج 3581 - 3590 من 4,033
Dietary unsaponifiable fraction of extra virgin olive oil supplementation attenuates lung injury and DNA damage of rats co-exposed to aluminum and acrylamide
2016
Ghorbel, Imen | Chaâbane, Mariem | Boudawara, Ons | Kamoun, Naziha Grati | Boudawara, Tahia | Zeghal, Najiba
Aluminum chloride (AlCl₃) and acrylamide (ACR) are well known as environmental pollutants inducing oxidative stress. Our study investigated the effects of these contaminants and if the hydrophilic fraction of extra virgin olive oil was able to prevent lung oxidative stress and DNA damage. Animals were divided into four groups of six each: group 1, serving as controls, received distilled water; group 2 received in drinking water aluminum chloride (50 mg/ kg body weight) and by gavage acrylamide (20 mg/kg body weight); group 3 received both aluminum and acrylamide in the same way and the same dose as group 2 and hydrophilic fraction from olive oil (OOHF) (1 ml) by gavage; group 4 received only OOHF by gavage. Exposure of rats to both aluminum and acrylamide provoked oxidative stress in lung tissue based on biochemical parameters and histopathological alterations. In fact, we have observed an increase in malondialdehyde (MDA), H₂O₂, and advanced oxidation protein product (AOPP) and a decrease in reduced glutathione (GSH), non-protein thiols (NPSH), and vitamin C levels. Activities of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were also decreased. Histopathological changes in lung tissue were noted like emphysema, vascular congestion, and infiltration of inflammatory cells. A random DNA degradation was observed on agarose gel in the lung of AlCl₃ and acrylamide (ACR)-treated rats. Co-administration of OOHF to treated rats improved biochemical parameters to near control values and lung histoarchitecture. The smear formation of genomic DNA was reduced. The hydrophilic fraction of extra virgin olive oil might provide a basis for developing a new dietary supplementation strategy in order to prevent lung tissue damage.
اظهر المزيد [+] اقل [-]Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis
2016
Zhou, Qiongzhi | Li, Feng | Ge, Fei | Liu, Na | Kuang, Yangduo
Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H⁺-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH₄ ⁺) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows () represent the increase and the red arrow () represents the decrease.
اظهر المزيد [+] اقل [-]Application of gas diffusion biocathode in microbial electrosynthesis from carbon dioxide
2016
Bajracharya, Suman | Vanbroekhoven, Karolien | Buisman, Cees J.N. | Pant, Deepak | Strik, David P. B. T. B.
Microbial catalysis of carbon dioxide (CO₂) reduction to multi-carbon compounds at the cathode is a highly attractive application of microbial electrosynthesis (MES). The microbes reduce CO₂ by either taking the electrons or reducing the equivalents produced at the cathode. While using gaseous CO₂ as the carbon source, the biological reduction process depends on the dissolution and mass transfer of CO₂ in the electrolyte. In order to deal with this issue, a gas diffusion electrode (GDE) was investigated by feeding CO₂ through the GDE into the MES reactor for its reduction at the biocathode. A combination of the catalyst layer (porous activated carbon and Teflon binder) and the hydrophobic gas diffusion layer (GDL) creates a three-phase interface at the electrode. So, CO₂ and reducing equivalents will be available to the biocatalyst on the cathode surface. An enriched inoculum consisting of acetogenic bacteria, prepared from an anaerobic sludge, was used as a biocatalyst. The cathode potential was maintained at −1.1 V vs Ag/AgCl to facilitate direct and/or hydrogen-mediated CO₂ reduction. Bioelectrochemical CO₂ reduction mainly produced acetate but also extended the products to ethanol and butyrate. Average acetate production rates of 32 and 61 mg/L/day, respectively, with 20 and 80 % CO₂ gas mixture feed were achieved with 10 cm² of GDE. The maximum acetate production rate remained 238 mg/L/day for 20 % CO₂ gas mixture. In conclusion, a gas diffusion biocathode supported bioelectrochemical CO₂ reduction with enhanced mass transfer rate at continuous supply of gaseous CO₂. Graphical abstract ᅟ
اظهر المزيد [+] اقل [-]Exploratory study on the presence of GM oilseed rape near German oil mills
2016
Franzaring, J. | Wedlich, K. | Fangmeier, A. | Eckert, S. | Zipperle, J. | Krah-Jentgens, I. | Hünig, C. | Züghart, W.
Seed losses from imported oilseed rape (OSR) and the genetically modified (GM) admixtures therein may potentially lead to the establishment of transgenic plants and their hybridization with wild crucifers. The post-market environmental monitoring (PMEM) must therefore also address problems related to seed spillages of GM OSR. Since detailed information on imported commodity flows, GM contents, means of transport, downstream users and efficient containment of GM OSR was lacking, we performed a field study in the vicinity of large oil mills and seed processing industries at the harbours along the river Rhine. One hundred thirty-six composite samples taken from one to 20 plants per site were collected near roads, railways and waterways. Individuals or large groups of feral OSR plants were detected in all of the nine study areas, but only one plant out of 1918 tested was confirmed to be transgenic (GT73). The results suggest that a spread of herbicide tolerant GM OSR has not occurred to date. In order to confirm the absence of GM feral OSR and potentially adverse effects of GM plants in the future, we recommend monitoring feral OSR on a routine basis. We present an approach for the sampling and testing of feral OSR that is based on floristic mapping and rapid tests for the determination of herbicide tolerances.
اظهر المزيد [+] اقل [-]Influence of soil contamination with PAH on microbial community dynamics and expression level of genes responsible for biodegradation of PAH and production of rhamnolipids
2016
Szczepaniak, Zuzanna | Czarny, Jakub | Staninska-Pięta, Justyna | Lisiecki, Piotr | Zgoła-Grześkowiak, Agnieszka | Cyplik, Paweł | Chrzanowski, Łukasz | Wolko, Łukasz | Marecik, Roman | Juzwa, Wojciech | Glazar, Katarzyna | Piotrowska-Cyplik, Agnieszka
The aim of this study was to evaluate the effect of bioaugmentation and addition of rhamnolipids on the biodegradation of PAHs in artificially contaminated soil, expression of genes crucial for the biodegradation process (PAHRHDαGN, PAHRHDαGP), and the synthesis of rhamnolipids as well as population changes in the soil bacterial metabiome. The positive effect of bioaugmentation and addition of rhamnolipids on the bioremediation of the majority of PAHs was confirmed during the early stages of treatment, especially in case of the most structurally complicated compounds. The results of metagenomic analysis indicated that the initial changes in the soil metabiome caused by bioaugmentation diminished after 3 months and that the community structure in treated soil was similar to control. The survival period of bacteria introduced into the soil via bioaugmentation reached a maximum of 3 months. The increased expression of genes observed after addition of PAH into the soil also returned to the initial conditions after 3 months.
اظهر المزيد [+] اقل [-]Fluorescent components and spatial patterns of chromophoric dissolved organic matters in Lake Taihu, a large shallow eutrophic lake in China
2016
Yao, Bo | Hu, Chunming | Liu, Qingquan
Water samples at both surface and bottom layers were taken from 102 sites in Lake Taihu to study the fluorescent components and spatial patterns of chromophoric dissolved organic matters (CDOM). Three-dimensional excitation-emission matrix data obtained from the samples were analyzed by parallel factor approach in which four humic-like and two protein-like fluorescent components (named C1–C6) were identified. The results showed that fluorescence intensities were higher in the northern and western lake regions, and notable declines of fluorescence maxima (F ₘₐₓ) were observed from the northwest to the center and then to the southeast of the lake. Calculated biological index (BIX) values ranged from 0.88 to 1.44 and humification index (HIX) values from 0.64 to 3.37 for all the samples. The spatial variations of BIX and HIX values suggested stronger allochthonous CDOM characteristics in Zhushan Bay and the western area and autochthonous characteristics in the southern and eastern areas. Vertically, the average F ₘₐₓ value of the surface samples was about 6 % less than that of the bottom samples, but noticeable variations existed among different sampling sites and components. These distribution characteristics of CDOM were mainly attributed to the spatial heterogeneity of sources and wind-induced transportation process. Interestingly, the C6 component (Exₘₐₓ/Emₘₐₓ = 250/455 nm) seemed to be unique in samples from Zhushan Bay and probably resulted from the discharge of the Taige River. Therefore, it could be used as an indicator of point-source discharge and a tracer to study the fate of CDOM in the lake.
اظهر المزيد [+] اقل [-]A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry
2016
Li, Baosheng | Wang, Yicheng | Li, Zhengqiang
A method for measurements of mass concentration of black carbon particulate matter (PM) is proposed based on photothermal interferometry (PTI). A folded Jamin photothermal interferometer was used with a laser irradiation of particles deposited on a filter paper. The black carbon PM deposited on the filter paper was regarded as a film while the quartz filter paper was regarded as a substrate to establish a mathematical model for measuring the mass concentration of PM using a photothermal method. The photothermal interferometry system was calibrated and used to measure the atmospheric PM concentration corresponding to different dust-treated filter paper. The measurements were compared to those obtained using β ray method and were found consistent. This method can be particularly relevant to polluted atmospheres where PM is dominated by black carbon.
اظهر المزيد [+] اقل [-]Ionic liquid-modified silica-coated magnetic nanoparticles: promising adsorbents for ultra-fast extraction of paraquat from aqueous solution
2016
Latifeh, Farzad | Yamini, Yadollah | Seidi, Shahram
In the present study, ionic liquid-modified silica-coated magnetic nanoparticles (Fe₃O₄@SiO₂@IL) were synthesized and applied as adsorbents for extraction and determination of paraquat (PQ) followed by high-performance liquid chromatography. For assurance of the extraction efficiency, the obtained results were compared with those obtained by bared magnetic nanoparticles (MNPs). Experimental design and response surface methodology were used for optimization of different parameters which affect extraction efficiency of paraquat using both adsorbents. Under the optimized conditions, extraction recoveries in the range of 20–25 and 35–40 % with satisfactory repeatability values (RSDs%, n = 4) less than 5.0 % were obtained for bared MNPs and Fe₃O₄@SiO₂@IL, respectively. The limits of detection were 0.1 and 0.25 μg/L using Fe₃O₄@SiO₂@IL and bared MNPs, respectively. The linearity was obtained in the range of 0.25 to 25 μg/L and 0.5 to 25 μg/L for Fe₃O₄@SiO₂@IL and bared MNPs, respectively, with the coefficients of determination better than 0.9950. Finally, Fe₃O₄@SiO₂@IL was chosen as superior adsorbent due to more dispersion ability, higher extraction recovery, lower detection limit, as well as better linearity and repeatability. Calculated errors (%) were in the range of 3 to 10 % depicting acceptable accuracy for the analysis of PQ by the proposed method. Finally, the method was successfully applied for extraction and determination of PQ in some water and countryside soil samples.
اظهر المزيد [+] اقل [-]Ce-Fe-reduced graphene oxide nanocomposite as an efficient catalyst for sulfamethazine degradation in aqueous solution
2016
Wan, Zhong | Wang, Jianlong
A heterogeneous Fenton catalyst Ce⁰–Fe⁰-reduced graphene oxide (Ce–Fe–RGO) was synthesized with chemical reduction methods and used for degradation of sulfamethazine. The introduction of Ce and graphene increased the dispersibility of iron particles which was confirmed by SEM and TEM. The results of VSM analysis showed good magnetism of Ce–Fe–RGO. The catalyst performance was compared with other kinds of catalysts (Fe⁰ and Ce⁰–Fe⁰) for degradation of sulfamethazine. The results showed that Ce⁰–Fe–RGO had good catalytic performance and adsorption. X-ray diffraction showed the change of iron oxide on catalyst surface after use. The total sulfur (TS), total nitrogen (TN), total organic carbon (TOC), and intermediates, such as small organic molecular and anion ions, were analyzed by IC under different pH conditions. Finally, the possible catalytic mechanism was tentatively proposed based on inhibitor experimental results and XPS characterization. The main active species was hydroxyl radical on catalyst surface and the transition between Ce³⁺ and Ce⁴⁺ which enhanced the reduction from Fe³⁺ to Fe²⁺ and formation of ·OH and ·O₂ ⁻.
اظهر المزيد [+] اقل [-]Microbenthic community structure and trophic status of sediments in the Mar Piccolo of Taranto (Mediterranean, Ionian Sea)
2016
Rubino, F. | Cibic, T. | Belmonte, M. | Rogelja, M.
This study aimed to assess the benthic ecosystem trophic status in a heavily polluted marine area and the response of the microbenthic community to multiple and diffuse anthropogenic impacts, integrating information coming from the active and resting (plankton’s cysts) components of microbenthos. Two sampling campaigns were carried out in the period 2013–2014 and four sampling sites at different levels of industrial contamination were chosen within the first and second inlet of the Mar Piccolo of Taranto. The chemical contamination affected to a higher extent the active microbenthos than the resting one. In the central part of the first inlet, characterised by more marine features, thrives a very rich and biodiverse microbenthic community. In contrast, at the polluted site near the military navy arsenal, extremely low densities (9576 ± 1732 cells cm⁻³) were observed for active microbenthos, but not for the resting community. Here, the high level of contamination selected for tychopelagic diatom species, i.e., thriving just above the surface sediments, while the other life forms died or moved away. Following the adoption of a 10 μm mesh, for the first time, resting spores produced by small diatoms of the genus Chaetoceros were found. Our results further indicate that although the Mar Piccolo is very shallow, the benthic system is scarcely productive, likely as a consequence of the accumulated contaminants in the surface sediments that probably interfere with the proper functioning of the benthic ecosystem.
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