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Sorption of his-tagged Protein G and Protein G onto chitosan/divalent metal ion sorbent used for detection of microcystin-LR
2017
Demey, Hary | Tria, Scherrine A. | Soleri, Romain | Guiseppi-Elie, Anthony | Bazin, Ingrid
A highly sensitive, specific, simple, and rapid chemiluminescence enzyme immunoassay (CLEIA) was developed for the determination of microcystin-LR (MC-LR) by using strategies for oriented immobilization of functionally intact polyclonal antibodies on chitosan surface. Several physicochemical parameters such as metal ion adsorption, hexahistidine-tagged Protein G sorption, the dilution ratio polyclonal antibody concentration, and peroxidase-labeled MC-LR concentration were studied and optimized. The sorption in batch system of G-histidine and G-proteins was studied on a novel sorbent consisting of chitosan/divalent metal ions. Transition metals as Ni⁺⁺ and Zn⁺⁺ were immobilized through interaction with –NH₂ groups of chitosan in order to supply a material capable to efficiently remove the proteins from aqueous solutions. The maximum uptake of divalent metals onto the chitosan material was found to be 230 mg g⁻¹ for Zn⁺⁺ and 62 mg g⁻¹ for Ni⁺⁺. Experimental data were evaluated using the Langmuir and Freundlich models; the results were well fitted with the Langmuir model; chitosan/Ni⁺⁺ foam was found to be the best sorbent for G-protein, maximum sorption capacity obtained was 17 mg g⁻¹, and chitosan/Zn⁺⁺ was found to be the best for G-histidine with a maximum sorption capacity of 44 mg g⁻¹. Kinetic data was evaluated with pseudo-first- and pseudo-second-order models; the sorption kinetics were in all cases better represented by a pseudo-second-order model. Under optimum conditions, the calibration curve obtained for MC-LR gave detection limits of 0.5 ± 0.06 μg L⁻¹, the 50 % inhibition concentration (IC50) was 2.75 ± 0.03 μg L⁻¹, and the quantitative detection range was 0.5–25 μg L⁻¹. The limit of detection (LOD) attained from the calibration curves and the results obtained demonstrate the potential use of CLEIA with chitosan support as a screening tool for the analysis of pollutants in environmental samples.
Afficher plus [+] Moins [-]A bioluminescent arsenite biosensor designed for inline water analyzer
2017
Prévéral, Sandra | Brutesco, Catherine | Descamps, Elodie C. T. | Escoffier, Camille | Pignol, David | Ginet, Nicolas | Garcia, Daniel
Whole-cell biosensors based on the reporter gene system can offer rapid detection of trace levels of organic or metallic compounds in water. They are well characterized in laboratory conditions, but their transfer into technological devices for the surveillance of water networks remains at a conceptual level. The development of a semi-autonomous inline water analyzer stumbles across the conservation of the bacterial biosensors over a period of time compatible with the autonomy requested by the end-user while maintaining a satisfactory sensitivity, specificity, and time response. We focused here on assessing the effect of lyophilization on two biosensors based on the reporter gene system and hosted in Escherichia coli. The reporter gene used here is the entire bacterial luciferase lux operon (luxCDABE) for an autonomous bioluminescence emission without the need to add any substrate. In the cell-survival biosensor that is used to determine the overall fitness of the bacteria when mixed with the water sample, lux expression is driven by a constitutive E. coli promoter PᵣₚₒD. In the arsenite biosensor, the arsenite-inducible promoter P ₐᵣₛ involved in arsenite resistance in E. coli controls lux expression. Evaluation of the shelf life of these lyophilized biosensors kept at 4 °C over a year evidenced that about 40 % of the lyophilized cells can be revived in such storage conditions. The performances of the lyophilized biosensor after 7 months in storage are maintained, with a detection limit of 0.2 μM arsenite for a response in about an hour with good reproducibility. These results pave the way to the use in tandem of both biosensors (one for general toxicity and one for arsenite contamination) as consumables of an autonomous analyzer in the field.
Afficher plus [+] Moins [-]The effect of the feeding pattern of complex industrial wastewater on activated sludge characteristics and the chemical and ecotoxicological effluent quality
2017
Caluwé, Michel | Dobbeleers, Thomas | Daens, Dominique | Blust, Ronny | Geuens, Luc | Dries, Jan
Research has demonstrated that the feeding pattern of synthetic wastewater plays an important role in sludge characteristics during biological wastewater treatment. Although considerable research has been devoted to synthetic wastewater, less attention has been paid to industrial wastewater. In this research, three different feeding strategies were applied during the treatment of tank truck cleaning (TTC) water. This industry produces highly variable wastewaters that are often loaded with hazardous chemicals, which makes them challenging to treat with activated sludge (AS). In this study, it is shown that the feeding pattern has a significant influence on the settling characteristics. Pulse feeding resulted in AS with a sludge volume index (SVI) of 68 ± 15 mL gMLSS⁻¹. Slowly and continuously fed AS had to contend with unstable SVI values that fluctuated between 100 and 600 mL gMLSS⁻¹. These fluctuations were clearly caused by the feeding solution. The obtained settling characteristics are being supported by the microscopic analysis, which revealed a clear floc structure for the pulse fed AS. Ecotoxicological effluent assessment with bacteria, Crustacea and algae identified algae as the most sensitive organism for all effluents from all different reactors. Variable algae growth inhibitions were measured between the different reactors. The chemical and ecotoxicological effluent quality was comparable between the reactors.
Afficher plus [+] Moins [-]Estrogen receptor beta mediates hepatotoxicity induced by perfluorooctane sulfonate in mouse
2017
Xu, Cheng | Jiang, Zhao-Yan | Liu, Qian | Liu, Hui | Gu, Aihua
Perfluorooctane sulfonate (PFOS), an artificial fluorosurfactant and global contaminant, is used widely in various consumer products. In this study, we investigated the function of estrogen receptor β (ERβ) in PFOS-induced bile acid and cholesterol metabolism disorders and gut microbiome using ERβ knockout mice that were exposed to PFOS by gavage. Our results showed that a daily dose of 5 mg PFOS/kg significantly induced hydropic degeneration and vacuolation in hepatic cells, reduced bile acid, and cholesterol levels in liver tissue, and influenced the abundance and composition of gut microbiota. Notably, ERβ deficiency not only ameliorated morphological alterations of hepatocytes but also relieved disorders in bile acids and cholesterol metabolism caused by PFOS. Furthermore, the changes in the gut microbiome by PFOS were also modulated. The relative transcript abundance of key genes involved in bile acid and cholesterol metabolism exhibited similar changes. In HepG2 cells, PFOS increased ERβ expression, which could be blocked by adding PHTPP (a selective antagonist of ERβ). Our study thus provides new evidence that ERβ mediates PFOS-induced hepatotoxicity.
Afficher plus [+] Moins [-]Migration of nitrate, nitrite, and ammonia through the municipal solid waste incinerator bottom ash layer in the simulated landfill
2017
Yao, Jun | Chen, Luxi | Zhu, Huayue | Shen, Dongsheng | Qiu, Zhanhong
Simulated landfill was operated for 508 days to investigate the effect of municipal solid waste incinerator (MSWI) bottom ash layer on the migration of nitrate, nitrite, and ammonia when it was used as the intermediate layer in the landfill. The result suggested that the MSWI bottom ash layer could capture the nitrate, nitrite, and ammonia from the leachate. The adsorption of the nitrate, nitrite, and ammonia on the MSWI bottom ash layer was saturated at the days 396, 34, and 97, respectively. Afterwards, the nitrogen species were desorbed from the MSWI bottom ash layer. Finally, the adsorption and desorption could reach the equilibrium. The amounts of adsorbed nitrate and nitrite on the MSWI bottom ash layer were 1685.09 and 7.48 mg, respectively, and the amount of the adsorbed and transformed ammonia was 13,773.19 mg, which was much higher than the desorbed. The water leaching test and synthetic precipitation leaching procedure (SPLP) results showed that the leachable nitrate, nitrite, and ammonia in the MSWI bottom ash were greatly increased after the landfill operation, suggesting that the adsorbed nitrogen could be finally leached out. Besides, the results also showed that MSWI bottom ash layer could affect the release of nitrate and ammonia at the initial stage of the landfill. However, it had little effect on the release of nitrite.
Afficher plus [+] Moins [-]Life cycle environmental impacts of bioethanol production from sugarcane molasses in Iran
2017
Farahani, SaeidShahvarooghi | Asoodar, MohammadAmin
In recent years, bioethanol from sugarcane molasses has been produced on an industrial scale in Iran. The aim of this study was to evaluate molasses-based bioethanol production from an environmental point of view. Data were collected from Debel Khazai agro-industry situated in southern region of Iran by using face-to-face interviews and annual statistics of 2010 to 2016 (6-year life cycle of sugarcane cultivation). Ten impact categories including abiotic depletion (AD), acidification (AC), eutrophication (EP), global warming potential (GWP), ozone layer depletion (OLD), human toxicity (HT), freshwater aquatic ecotoxicity (FE), marine aquatic ecotoxicity (ME), terrestrial ecotoxicity (TE), and photochemical oxidation (PO) were selected based on CML methodology. Inventory data for production of the inputs were taken from Ecoinvent, BUWAL 250, and IDMAT 2001 databases. The results revealed that in sugarcane cultivation process, electricity and trash burning were the most important contributors to all impact categories except OLD and TE. In industrial phase, natural gas had the highest contribution to the most impact categories. Greenhouse gas (GHG) emission for production of 1000 L molasses-based bioethanol was 1322.78 kg CO₂ eq. By comparing total GHG emissions from 1000 L bioethanol to gasoline, the net avoided GHG emissions came out at 503.17 kg CO₂ eq. According to results, it is clear that with increasing irrigation efficiency and improving performance of heating systems in industrial phase, environmental burdens would be significantly reduced.
Afficher plus [+] Moins [-]Association of lead exposure with cardiovascular risk factors and diseases in Chinese adults
2017
Chen, Chi | Li, Qin | Nie, Xiaomin | Han, Bing | Chen, Yi | Xia, Fangzhen | Zhai, Hualing | Wang, Ningjian | Lu, Yingli
We aimed to determine whether lead exposure was associated with cardiovascular diseases (CVD) and risk factors in Chinese adults. Five thousand three hundred and forty-eight subjects were enrolled from 16 sites in China. Blood lead level (BLL) was measured by atomic absorption spectrometry. Cardiovascular diseases included coronary heart disease, stroke, and myocardial infarction. Cardiovascular risk factors included body mass index (BMI), fasting plasma glucose (FPG), lipid profile, and blood pressure. We found that 5.9% of the study population had prevalent CVD. Medians (interquartile range) of BLLs were 44.00 μg/L (29.00–62.48) for men and 37.70 μg/L (25.00–54.60) for women. The prevalence of CVD gradually and markedly increased with increasing BLL quartiles in women (P for trend < 0.01), but not in men. After adjustment for age, current smoking, and drinking, BLLs were independently associated with cardiovascular risk factors including BMI, FPG, and blood pressure in women (all P < 0.05), but not in men. Binary logistic regression showed that increased quartiles of BLL were significantly and positively associated with increased odds ratio of prevalent CVD (P for trend < 0.01) in women. This association was independent of age, smoking, drinking, education, diabetes, obesity, hypertension, and lipid profile. In conclusion, BLL in the range currently considered acceptable is independently associated with CVD, which is the leading cause of death in China. Further practical and cost-effective efforts to reduce lead exposure may be warranted.
Afficher plus [+] Moins [-]X-ray metal assessment and ovarian ultrastructure alterations of the beetle, Blaps polycresta (Coleoptera, Tenebrionidae), inhabiting polluted soil
2017
Osman, Wafaa | Shonouda, Mourad
X-ray analysis was applied to estimate the percentages of heavy metals in ovarian tissues of the tenebrionid beetle, Blaps polycresta. Calcium, phosphorus, sulfur, cadmium, copper, and zinc were the most common detected metals in ovaries of insects collected from reference and polluted sites. Only cadmium showed significantly higher percentages in the polluted ovaries compared with the reference ones. Ultrastructure investigation revealed severe alterations in polluted ovaries both in the tropharium and in the vitellarium. Contraction of nuclear membrane of trophocytes was observed; therefore, cavities and spaces appeared in the cytoplasm followed by nuclear pyknosis. In the vitellarium, fragmentation of chromatin materials in nuclei of the follicular cells was detected. The cytoplasm was poor in the rough endoplasmic reticulum and mitochondria. Damage of yolk bodies occurred in addition to break off in the layer of microvilli. Accumulation of electron-dense vesicles and multivesicular bodies were observed in both reference and polluted ovaries. These alterations in ovarian ultrastructure of B. polycresta show the severe impact of cadmium pollution on cell organelles of insects and could be used as an interesting tool for monitoring heavy metals inside the body organs due to soil pollution.
Afficher plus [+] Moins [-]Silicon and Rhizophagus irregularis: potential candidates for ameliorating negative impacts of arsenate and arsenite stress on growth, nutrient acquisition and productivity in Cajanus cajan (L.) Millsp. genotypes
2017
Garg, Neera | Kashyap, Lakita
Arsenic (As) gets accumulated in plants via phosphorous transporters and water channels and interferes with nutrient and water uptake, adversely affecting growth and productivity. Although, Si and AM have been reported to combat arsenic stress, their comparative and interactive roles in ameliorating As V and As III toxicities have not been reported. Study evaluated effects of Si and Rhizophagus irregularis on growth, As uptake and yield under arsenate and arsenite stress in two pigeonpea genotypes (metal tolerant—Pusa 2002 and metal sensitive—Pusa 991). Higher As accumulation and translocation was observed in As III treated roots of Pusa 991 than those of Pusa 2002 when compared with As V. Roots were more negatively affected than shoots which led to a significant decline in nutrient uptake, leaf chlorophylls, and yield, with As III inducing more negative effects. Pusa 2002 established more effective mycorrhizal symbiosis and had higher biomass than Pusa 991. Si was more effective in inducing shoot biomass while AM inoculation significantly improved root biomass. AM enhanced Si uptake in roots and leaves in a genotype dependent manner. Combined application of Si and AM were highly beneficial in improving leaf water status, chlorophyll pigments, biomass, and productivity. Complete amelioration of negative impacts of both concentrations of As V and lower concentration of As III were recorded under +Si +AM in Pusa 2002. Results highlighted great potential of Si in improving growth and productivity of pigeonpea through R. irregularis under As V and As III stresses.
Afficher plus [+] Moins [-]Palm oil mill effluent treatment and CO2 sequestration by using microalgae—sustainable strategies for environmental protection
2017
Hariz, Harizah Bajunaid | Takriff, Mohd Sobri
In this era of globalization, various products and technologies are being developed by the industries. While resources and energy are utilized from processes, wastes are being excreted through water streams, air, and ground. Without realizing it, environmental pollutions increase as the country develops. Effective technology is desired to create green factories that are able to overcome these issues. Wastewater is classified as the water coming from domestic or industrial sources. Wastewater treatment includes physical, chemical, and biological treatment processes. Aerobic and anaerobic processes are utilized in biological treatment approach. However, the current biological approaches emit greenhouse gases (GHGs), methane, and carbon dioxide that contribute to global warming. Microalgae can be the alternative to treating wastewater as it is able to consume nutrients from wastewater loading and fix CO₂ as it undergoes photosynthesis. The utilization of microalgae in the system will directly reduce GHG emissions with low operating cost within a short period of time. The aim of this review is to discuss the uses of native microalgae species in palm oil mill effluent (POME) and flue gas remediation. In addition, the discussion on the optimal microalgae cultivation parameter selection is included as this is significant for effective microalgae-based treatment operations.
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