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Antibiotic resistance pattern and gene expression of non-typhoid Salmonella in riversheds Texte intégral
2015
Hsu, Chao-Yu | Hsu, Bing-Mu | Ji, Wen-Tsai | Chen, Jung-Sheng | Hsu, Tsui-Kang | Ji, Dar-Der | Tseng, Shao-Feng | Chiu, Yi-Chou | Kao, Po-Min | Huang, Youli
In this study, antibiotic resistance and major phenol and genotypes of non-typhoid Salmonella spp. from riversheds in Taiwan were examined. In 236 water samples tested, 54 (22.9 %) contained Salmonella spp. Fifteen Salmonella serovars were identified from the Salmonella isolates, and some common serovars are associated with infections of human and livestock, including Albany (27.8 %), Newport (14.8 %), Bareilly (13.0 %), Derby (11.1 %), and Typhimurium (7.4 %). Various environmental factors may also affect the presence and proportion of different serovars in the receiving waters. In contrast, serovars with narrower range of hosts, e.g., Dublin, were rarely detected. The Salmonella isolates were subjected to eight antibiotics for drug resistance, and 51.9 % of the samples were resistant to at least one tested antibiotics. Tetracycline and sulfadiazine were the two most ineffective antibiotics against the Salmonella isolates, and the results were indicative of long-term antibiotics abuse as fodder supplements in animal husbandry. The more commonly detected serovars such as Albany, Derby, and Typhimurium were also more likely to be resistant to multiple antibiotics. Finally, a significant correlation was observed between resistance to chloramphenicol and the resistance gene cmlA, suggesting that the resistance genotypes could persist in the environment even long after prohibition of the drug use. The high prevalence of antibiotic-resistant Salmonella spp. infers elevated infection risks that must be further examined.
Afficher plus [+] Moins [-]The endocrine-disrupting effect and other physiological responses of municipal effluent on the clam Ruditapes decussatus Texte intégral
2015
Mezghani-Chaari, Sawssan | Machreki-Ajmi, Monia | Tremolet, Gauthier | Kellner, Kristell | Geffard, Alain | Minier, Christophe | Hamza-Chaffai, Amel
In order to document the potential endocrine disrupting and toxic effect of the municipal wastewater effluents discharged into the Sfax coastal area (South of Tunisia), specimens of clam R. decussatus were collected from a reference site and were in vivo exposed to treated sewage effluent for 30 days. To this end, estrogenic and androgenic activities were measured in the gills to assess potential accumulation and regulation of active compounds. After effluent exposure androgenic activity in organic extracts increased up to fivefold compared to controls and remained elevated, while estrogenic activity was not significantly affected by exposure. As a consequence, remarkable disruptions in the gametogenesis activity, glycogen content, and Vitellogenin-like protein levels in male clams were observed. A parallel analysis of heavy metals in clam tissues was determined. A significant uptake of Ni, Zn, and Pb in soft tissues of exposed clams was observed. The significant increase of malondialdehyde (MDA) concentrations as a function of exposure time implies that clams have been exposed to an oxidative stress probably due to the presence of high metal concentrations in sewage effluent. Correlation analysis has revealed a statistically significant and positive relationship between MDA levels and metal concentrations in clams’ tissues. The acetylcholinesterase activity was not significantly affected by exposure. Altogether, these results showed that a short-term exposure to a mixture of chemical compounds released by the Sfax wastewater treatment plant induce adverse physiological and reproductive effects in R. decussatus. Further studies are underway in order to evaluate its long-term impacts on aquatic wildlife in the gulf of Gabes area.
Afficher plus [+] Moins [-]BFCOD activity in fish cell lines and zebrafish embryos and its modulation by chemical ligands of human aryl hydrocarbon and nuclear receptors Texte intégral
2015
Creusot, N. | Brion, F. | Piccini, B. | Budzinski, H. | Porcher, J. M. | Aït-Aïssa, S.
BFCOD activity in fish cell lines and zebrafish embryos and its modulation by chemical ligands of human aryl hydrocarbon and nuclear receptors Texte intégral
2015
Creusot, N. | Brion, F. | Piccini, B. | Budzinski, H. | Porcher, J. M. | Aït-Aïssa, S.
Assessment of exposure and effect of fish to pharmaceuticals that contaminate aquatic environment is a current major issue in ecotoxicology and there is a need to develop specific biological marker to achieve this goal. Benzyloxy-4-trifluoromethylcoumarin-O-debenzyloxylase (BFCOD) enzymatic activity has been commonly used to monitor CYP3A activity in fish. In this study, we assessed the capacity of a panel of toxicologically relevant chemicals to modulate BFCOD activity in fish, by using in vitro and in vivo bioassays based on fish liver cell lines (PLHC-1, ZFL, RTL-W1) and zebrafish embryos, respectively. Basal BFCOD activity was detectable in all biological models and was differently modulated by chemicals. Ligands of human androgens, glucocorticoids, or pregnanes X receptors (i.e., dexamethasone, RU486, rifampicin, SR12813, T0901317, clotrimazole, ketoconazole, testosterone, and dihydrotestosterone) moderately increased or inhibited BFCOD activity, with some variations between the models. No common feature could be drawn by regards to their capacity to bind to these receptors, which contrasts with their known effect on mammalian CYP3A. In contrast, dioxins and polycyclic aromatic hydrocarbons (PAHs) strongly induced BFCOD activity (up to 30-fold) in a time- and concentration-dependent manner, both in vitro in all cell lines and in vivo in zebrafish embryos. These effects were AhR dependent as indicated by suppression of induced BFCOD by the AhR pathway inhibitors 8-methoxypsoralen and α-naphthoflavone. Altogether our result further question the relevance of using liver BFCOD activity as a biomarker of fish exposure to CYP3A-active compounds such as pharmaceuticals.
Afficher plus [+] Moins [-]BFCOD activity in fish cell lines and zebrafish embryos and its modulation by chemical ligands of human aryl hydrocarbon and nuclear receptors Texte intégral
2015
Creusot, Nicolas | Brion, F. | Piccini, B. | Budzinski, H. | Porcher, J. | Aït-Aïssa, S.
An integrated GIS-based interval-probabilistic programming model for land-use planning management under uncertainty—a case study at Suzhou, China Texte intégral
2015
Lu, Shasha | Zhou, Min | Guan, Xingliang | Tao, Lizao
A large number of mathematical models have been developed for supporting optimization of land-use allocation; however, few of them simultaneously consider land suitability (e.g., physical features and spatial information) and various uncertainties existing in many factors (e.g., land availabilities, land demands, land-use patterns, and ecological requirements). This paper incorporates geographic information system (GIS) technology into interval-probabilistic programming (IPP) for land-use planning management (IPP-LUPM). GIS is utilized to assemble data for the aggregated land-use alternatives, and IPP is developed for tackling uncertainties presented as discrete intervals and probability distribution. Based on GIS, the suitability maps of different land users are provided by the outcomes of land suitability assessment and spatial analysis. The maximum area of every type of land use obtained from the suitability maps, as well as various objectives/constraints (i.e., land supply, land demand of socioeconomic development, future development strategies, and environmental capacity), is used as input data for the optimization of land-use areas with IPP-LUPM model. The proposed model not only considers the outcomes of land suitability evaluation (i.e., topography, ground conditions, hydrology, and spatial location) but also involves economic factors, food security, and eco-environmental constraints, which can effectively reflect various interrelations among different aspects in a land-use planning management system. The case study results at Suzhou, China, demonstrate that the model can help to examine the reliability of satisfying (or risk of violating) system constraints under uncertainty. Moreover, it may identify the quantitative relationship between land suitability and system benefits. Willingness to arrange the land areas based on the condition of highly suitable land will not only reduce the potential conflicts on the environmental system but also lead to a lower economic benefit. However, a strong desire to develop lower suitable land areas will bring not only a higher economic benefit but also higher risks of violating environmental and ecological constraints. The land manager should make decisions through trade-offs between economic objectives and environmental/ecological objectives.
Afficher plus [+] Moins [-]Leydig cell number and sperm production decrease induced by chronic ametryn exposure: a negative impact on animal reproductive health Texte intégral
2015
Dantas, T. A. | Cancian, G. | Neodini, D. N. R. | Mano, D. R. S. | Capucho, C. | Predes, F. S. | Pulz, R Barbieri | Pigoso, A. A. | Dolder, H. | Severi-Aguiar, G. D. C.
Ametryn is an herbicide used to control broadleaf and grass weeds and its acute and chronic toxicity is expected to be low. Since toxicological data on ametryn is scarce, the aim of this study was to evaluate rat reproductive toxicity. Thirty-six adult male Wistar rats (90 days) were divided into three groups: Co (control) and T1 and T2 exposed to 15 and 30 mg/kg/day of ametryn, respectively, for 56 days. Testicular analysis demonstrated that ametryn decreased sperm number per testis, daily sperm production, and Leydig cell number in both treated groups, although little perceptible morphological change has been observed in seminiferous tubule structure. Lipid peroxidation was higher in group T2, catalase activity decreased in T1 group, superoxide dismutase activity diminished, and a smaller number of sulphydryl groups of total proteins were verified in both exposed groups, suggesting oxidative stress. These results showed negative ametryn influence on the testes and can compromise animal reproductive performance and survival.
Afficher plus [+] Moins [-]Total mercury and methylmercury distributions in surface sediments from Kongsfjorden, Svalbard, Norwegian Arctic Texte intégral
2015
Liu, Yang | Chai, Xiaoli | Hao, Yongxia | Gao, Xiaofeng | Lu, Zhibo | Zhao, Youcai | Zhang, Jie | Cai, Minghong
The total mercury (THg) and methylmercury (MeHg) distributions in the surface sediments of Kongsfjorden, Svalbard, in the Norwegian Arctic were investigated in this study. The results showed that THg concentrations ranged from 9.11 to 86.73 ng g⁻¹, whereas MeHg concentrations had an average of only 0.11 ng g⁻¹. Factors that control the distribution and methylated transformation of mercury were examined, and the results suggested that the movements of ocean currents and glaciers affect the THg distribution. The total organic carbon (TOC) and N contents in the sediments were positively correlated with THg concentration, which indicated that the THg distribution at these stations was primarily controlled by organic matter in the sediments. A complex relationship was observed between the THg and S contents, possibly due to anthropogenic activities involved in the perennial scientific expedition. MeHg and THg exhibited similar correlations with the sediment chemical characteristics for all stations suggesting that MeHg may be produced locally through the microbial methylation of mercury.
Afficher plus [+] Moins [-]Biodegradation of a biochar-modified waterborne polyacrylate membrane coating for controlled-release fertilizer and its effects on soil bacterial community profiles Texte intégral
2015
Zhou, Zijun | Du, Changwen | Li, Ting | Shen, Yazhen | Zeng, Yin | Du, Jie | Zhou, Jianmin
Biochar-modified polyacrylate-like polymers are promising waterborne polymer-based membrane coatings for controlled-release fertilizers. However, the effect of these membrane polymers on paddy soil is unknown. A soil incubation experiment was conducted using Fourier transform infrared photoacoustic spectroscopy to monitor the changes in the polymer-coated membranes in paddy soil, and Biolog EcoPlates and polymerase chain reaction-denaturing gradient gel electrophoresis were used to detect the effects of the membranes on soil bacterial community profiles. Compared to unmodified membranes, the biodegradation rate of the biochar-modified membrane was slower, and the membrane was more intact, which improved and guaranteed the controlled release of nutrients. Compared to the soil without membranes, the biochar-modified membranes, as well as unmodified ones, showed no significant impacts on the composition diversity of soil dominant bacterial community. The activity and functional diversity of soil culturable microbial community during the early stage of incubation were reduced by biochar-modified membranes due to the release of small amount of soluble organic materials but were both recovered in the 12ᵗʰ month of the incubation period. Therefore, the biochar-modified waterborne polyacrylate was environmentally friendly, demonstrating its potential both in the development of coated controlled-release fertilizers and in the utilization of crop residue.
Afficher plus [+] Moins [-]Phenol degradation using the mixed material clay/Fe immobilized on glass slides Texte intégral
2015
Taketa, Lidiane Yumi | Ignachewski, Franciély | Villalba, Juan Carlo | Anaissi, Fauze Jacó | Fujiwara, Sérgio Toshio
The mixed material clay/Fe was prepared and immobilized on glass slides and calcined at 550 and 750 °C. The calcined material X-ray powder pattern (XRD) diffractograms indicate that there is no intercalation of iron compounds inside the lamella clay. The experimental design revealed that the most suitable phenol degradation conditions were obtained using the material calcined at 750 °C in a pH 7 and 140 mg/L of hydrogen peroxide solution. The material MMAFe750 showed excellent performance as a catalyst for Fenton-like reaction; in 125 min, 50 % of phenol was removed in the absence of leaching-supported iron. These results indicate that the reaction occurs by a heterogeneous process. Furthermore, the material showed no loss of catalytic activity after five degradation studies. It was noted that the adsorption of phenol in the synthesized materials does not occur and the mixed material is strongly adsorbed onto glass slides.
Afficher plus [+] Moins [-]Effect of different sulfides on cadmium distribution during sludge combustion based on experimental and thermodynamic calculation approaches Texte intégral
2015
Liu, Jing-Yong | Fu, Jie-Wen | Sun, Shui-Yu | Ning, Xun-An | Wang, Yu-Jie | Chen, Tao | Luo, Guang-Qian | Xie, Wu-Ming | Yang, Zuo-Yi | Zhuo, Zhong-Xu
The effects of sulfur compounds on the migration of a semi-volatile heavy metal (cadmium) during sludge incineration were investigated with two methods, i.e., experiments in a tubular furnace reactor and thermodynamic equilibrium calculations. The representative typical sludge with and without the addition of sulfur compounds was incinerated at 850 °C. The partitioning of Cd among the solid phase (bottom ash) and gas phase (fly ash and flue gas) was quantified. The results indicate that sulfur compounds in the elemental form and a reduced state could stabilize Cd in the form of CdS, aluminosilicate minerals, and polymetallic sulfides, whereas sulfur in the oxidized forms slightly increases Cd volatilization during incineration. For Cd solidification points, the inhibition effect on the volatilization of Cd is as follows: S > Na₂SO₄> Na₂S. Chemical equilibrium calculations indicate that sulfur binds with Cd and alters Cd speciation at low temperatures (<950 K). Furthermore, SiO₂- and Al₂O₃-containing minerals can function as sorbents stabilizing Cd as condensed phase solids (CdSiO₄and CdAl₂O₄) according to the results of equilibrium calculations. These findings provide useful information for understanding the partitioning of Cd and thus facilitate the development of strategies to control Cd volatilization during sludge incineration.
Afficher plus [+] Moins [-]The use of vertical constructed wetland and ultrasound in aquaponic systems Texte intégral
2015
Krivograd Klemenčič, A. | Griessler Bulc, T.
Treatment performance, fish production, crop plant biomass production, water consumption, and water use efficiency of a pilot aquaponic system for small-scale land-based cyprinid fish farms were evaluated. The system consisted of a 36 m³Pond A with an initial carp load of 0.6 kg/m³; of a treatment chain with a lamellar settler, a roughing filter, a vertical constructed wetland filled with expanded clay and planted with tomatoes; and of a low power ultrasound unit installed in the corner of the pond. The average circulation of the water in the system was 1.2 times per day. Pond A was compared with Pond B of the same dimensions and fish load but with no treatment chain or ultrasound. The treatment chain was efficient in mass removal of total suspended solids , biochemical oxygen demand, chemical oxygen demand, NH₄-N, total nitrogen, and total phosphorous (57, 49, 35, 42, 31, and 25 %, respectively). Negative removal of NO₃-N, NO₂-N, and PO₄-P indicated the need for the introduction of additional hydroponic beds in the system. Pond A had markedly lower nutrient concentrations compared with Pond B. Fish body weight increase and specific growth rate in Pond A were higher than in Pond B (102.6 %, 72.1 %; 0.19 %/day, 0.14 %/day, respectively) indicating better rearing conditions in Pond A. Tomato biomass production was high. Water use efficiency was higher in Pond A compared with Pond B (0.31 kg of produced fish/m³inflow water and 0.22 kg of produced fish/m³inflow water, respectively). The presented aquaponic system could be useful for semi-natural fish farming with fish loads up to 2 kg/m³.
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