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Differential protein profile in zebrafish (Danio rerio) brain under the joint exposure of methyl parathion and cadmium
2012
Ling, Xue-Ping | Lu, Ying-Hua | Huang, He-Qing
As different chemicals, methyl parathion (MP) and cadmium (Cd) can induce neurotoxicity on the brain of aquatic ecosystems. This study aims to explore the differential expression proteins in the brain induced by their joint stress and their joint effects, which are poorly reported, and devotes finding novel biomarkers for monitoring their contamination in water and assessing their neurological effects. The bioaccumulation of MP and Cd in tissues after 96 h of exposure was first analyzed by GC and inductively coupled plasma–MS to provide insights into the interaction. Protein profile changes in the brains of the zebrafish (Danio rerio) exposed to MP and Cd were further investigated using the proteomic approach. The correlation of gene expression on the transcription level of mRNA and the translation level of protein was examined by real-time quantitative PCR and Western blotting analysis. It showed that Cd and MP have an interaction on their bioaccumulation, which suggests that their joint effect over 96 h might be antagonistic. Proteomics revealed that 22 protein spots changed their expression levels under stress, of which 16 proteins were identified using MS. These proteins were involved in oxidation/reduction, metabolism, energy production, receptor activity, and cytoskeleton assembly. Among them, five proteins with a remarkable abundance change are significantly suggested to play important roles in the joint effect. This work demonstrates that there exists an interaction between MP and Cd toxicities, which may aid in our understanding of the mechanism of neurotoxicity induced by joint stress. The results may also provide the possibility of the establishment of candidate biomarkers for monitoring MP and Cd contamination in water.
Show more [+] Less [-]Oxidative stress and detoxification biomarker responses in aquatic freshwater vertebrates exposed to microcystins and cyanobacterial biomass
2012
Paskerová, Hana | Hilscherová, Klára | Bláha, Luděk
Cyanobacterial blooms represent a serious threat to the aquatic environment. Among other effects, biochemical markers have been studied in aquatic vertebrates after exposures to toxic cyanobacteria. Some parameters such as protein phosphatases may serve as selective markers of exposure to microcystins, but under natural conditions, fish are exposed to complex mixtures, which affect the overall biomarker response. This review aims to provide a critical summary of biomarker responses in aquatic vertebrates (mostly fish) to toxic cyanobacteria with a special focus on detoxification and oxidative stress. Detoxification biomarkers such as glutathione (GSH) and glutathione-S-transferase (GST) showed very high variability with poor general trends. Often, stimulations and/or inhibitions and/or no effects at GSH or GST have been reported, even within a single study, depending on many variables, including time, dose, tissue, species, etc. Most of the oxidative stress biomarkers (e.g., superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) provided more consistent responses, but only lipid peroxidation (LPO) seemed to fulfill the criteria needed for biomarkers, i.e., a sufficiently long half-life and systematic response. Indeed, reviewed papers demonstrated that toxic cyanobacteria systematically elevate levels of LPO, which indicates the important role of oxidative damage in cyanobacterial toxicity. In summary, the measurement of biochemical changes under laboratory conditions may provide information on the mode of toxic action. However, comparison of different studies is very difficult, and the practical use of detoxification or oxidative stress biomarkers as diagnostic tools or early warnings of cyanobacterial toxicity is questionable.
Show more [+] Less [-]Algae community and trophic state of subtropical reservoirs in southeast Fujian, China
2012
Yang, Jun | Yu, Xiaoqing | Liu, Lemian | Zhang, Wenjing | Guo, Peiyong
BACKGROUND,: aim, and scope Fujian reservoirs in southeast China are important water resources for economic and social sustainable development, although few have been studied previously. In recent years, growing population and increasing demands for water shifted the focus of many reservoirs from flood control and irrigation water to drinking water. However, most of them showed a rapid increase in the level of eutrophication, which is one of the most serious and challenging environmental problems. In this study, we investigated the algae community characteristics, trophic state, and eutrophication control strategies for typical subtropical reservoirs in southeast Fujian. MATERIALS AND METHODS: Surface water samples were collected using polyvinyl chloride (PVC) plastic bottles from 11 Fujian reservoirs in summer 2010. Planktonic algae were investigated by optical microscopy. Water properties were determined according to the national standard methods. RESULTS AND DISCUSSION: Shallow reservoirs generally have higher values of trophic state index (TSI) and appear to be more susceptible to anthropogenic disturbance than deeper reservoirs. A total of 129 taxa belonging to eight phyla (i.e., Bacillariophyta, Chlorophyta, Chrysophyta, Cryptophyta, Cyanophyta, Euglenophyta, Pyrrophyta, Xanthophyta) were observed and the most diverse groups were Chlorophyta (52 taxa), Cyanophyta (20 taxa), Euglenophyta (17 taxa), Chrysophyta (14 taxa). The dominant groups were Chlorophyta (40.58%), Cyanophyta (22.91%), Bacillariophyta (21.61%), Chrysophyta (6.91%). The species richness, abundance, diversity, and evenness of algae varied significantly between reservoirs. TSI results indicated that all 11 reservoirs were eutrophic, three of them were hypereutrophic, six were middle eutrophic, and two were light eutrophic. There was a strong positive correlation between algal diversity and TSI at P < 0.05. Our canonical correspondence analysis (CCA) results illustrated that temperature, transparency, conductivity, DO, TC, NH4-N, NO x -N, TP, and chlorophyll a were significant environmental variables affecting the distribution of algae communities. The transparency and chlorophyll a were the strongest environmental factors in explaining the community data. Furthermore, the degradation of water quality associated with excess levels of nitrogen and phosphorus in Fujian reservoirs may be impacted by interactions among agriculture and urban factors. A watershed-based management strategy, especially phosphorus control, should be developed for drinking water source protection and sustainable reservoirs in the future. CONCLUSION AND RECOMMENDATIONS: All investigated reservoirs were eutrophicated based on the comprehensive TSI values; thus, our results provided an early warning of water degradation in Fujian reservoirs. Furthermore, the trophic state plays an important role in shaping community structure and in determining species diversity of algae. Therefore, long-term and regular monitoring of Euglenophyta, Cyanophyta, TN, TP and chlorophyll a in reservoirs is urgently needed to further understand the future trend of eutrophication and to develop a watershed-based strategy to manage the Cyanophyta bloom hazards.
Show more [+] Less [-]Removal of genotoxicity in chlorinated secondary effluent of a domestic wastewater treatment plant during dechlorination
2012
Wu, Qian-Yuan | Li, Yi | Hu, Hong-Ying | Ding, Ya-Nan | Huang, Huang | Zhao, Feng-Yun
PURPOSE: Dechlorination with tetravalent sulfur is widely used in wastewater treatment processes after chlorination. Dechlorination can remove certain genotoxic disinfection by-products (DBPs). However, the reactions occurring during dechlorination of chlorinated secondary effluent and their genotoxic chemicals are still very complex, and the related genotoxicity changes remain unknown. Therefore, the effects of dechlorination on genotoxicity in secondary effluent and its fractions and typical genotoxic chemical after chlorination were evaluated. METHODS: The dissolved organic matter in the secondary effluent sample was separated into four fractions with XAD-8 resin. Genotoxicity of secondary effluent and its fractions was evaluated by SOS/umu test, an ISO standard method. The concentration of typical genotoxic chemical named ofloxacin was determined by liquid chromatography with a mass spectrometer and a fluorescence detector. RESULTS: Dechlorination with the addition of Na2SO3 notably decreased the genotoxicity in the chlorinated secondary effluent, especially in the presence of high ammonia nitrogen concentration in the sample before chlorination. The Na2SO3 addition significantly decreased the genotoxicity of the secondary effluent and its genotoxic ofloxacin prior to chlorination. The genotoxicity in the fractions containing hydrophobic acids (HOA) increased after chlorination, while addition of Na2SO3 decreased the genotoxicity induced by chlorination. Tryptophan found in HOA exhibited genotoxicity after chlorination, while dechlorination decreased the genotoxicity in chlorinated tryptophan induced by DBPs. CONCLUSIONS: Dechlorination was found to decrease the genotoxicity of chlorinated secondary effluent. The decrease was associated with the reduction of genotoxicity in genotoxic chemicals in secondary effluent prior to chlorination and DBPs.
Show more [+] Less [-]Metal contamination of soils and plants associated with the glass industry in North Central India: prospects of phytoremediation
2012
Varun, Mayank | D’Souza, Rohan | Pratas, João | Paul, Manoj S.
INTRODUCTION: The effect of the glass industry on urban soil metal characterization was assessed in the area of Firozabad, India. A comprehensive profile of metal contamination was obtained in five zones each containing five specific sites. FINDINGS: Zn, Cd, and As showed a greater accumulation, whereas accumulation of Ni and Cu was high in limited samples. Positive correlation was found for the metal pairs Cu-Zn, Cu-Co, and Cu-Cr at P < 0.01. Moderate positive correlation was also observed between Zn-Co, Mn-Cd, Mn-As, Pb-As, and Ni-Cu at P < 0.05. Integrated contamination indices indicate that 60% of the sites were heavily contaminated while 28% were moderately contaminated. Phytoremedial potential of native flora (twenty herbs, three shrubs, and two grasses) was also assessed by analyzing their metal uptake. Individual elements displayed remarkably different patterns of accumulation in soils as well as in plants. Mn, Zn, Cu, and As were predominantly partitioned in shoots, Co and Cd in roots while Pb, Cr, and Ni almost equally between shoots and roots. Most plants exhibited capabilities in mobilizing Co, Pb, Cr, and Ni in the root zone. CONCLUSION: Potential phytoextractors include Datura stramonium and Chenopodium murale while phytostabilizers include Calotropis procera and Gnaphalium luteo-album. Poa annua showed potential in both categories. None of the species showed phytoremedial potential for Co and Ni.
Show more [+] Less [-]Efficacy of sludge and manure compost amendments against Fusarium wilt of cucumber
2012
Huang, Xiao | Strehlneek, E. A. | Sun, Faqian | Lu, Haohao | Liu, Jingjing | Wu, Weixiang
Fusarium wilt of cucumber caused by the fungus, Fusarium oxysporum, is one of the most destructive soilborne diseases and can result in serious economic loss. No efficient fungicide is currently available to control the disease. The aim of this study was to examine the disease suppression ability of pig manure and sludge composts in peat-based container media and explore the possible disease suppression mechanisms. Pig manure and sewage sludge compost were made in laboratory-scale tanks. Plant growth media were formulated with peat mixture and compost (or 60 °C heated compost) in a 4:1 ratio (v/v). Cucumber seedlings were artificially inoculated with F. oxysporum conidia (5 × 105 conidia mL−1) by the root-dip method. Cucumber Fusarium wilt was effectively suppressed in sludge compost-amended media, while the disease suppression effect of pig manure compost was limited. The ammonia levels in the manure compost-amended media were significantly higher than those of sludge compost-amended media, which could explain its lower disease suppression ability. Heated composts behaved similarly with respect to disease suppression. Adding composts increased microbial biomass, microbial activity, and the microbial diversity of the growth media. PCR-DGGE results indicated that the fungal community had a significant correlation to the disease severity. The artificially inoculated pathogen was retrieved in all treatments and one possible biocontrol agent was identified as a strain of F. oxysporum by phylogenetic analyses. The results indicated that the sludge compost used in this study could be applied as a method for biocontrol of cucumber Fusarium wilt.
Show more [+] Less [-]Pharmaceuticals on a sewage impacted section of a Mediterranean River (Llobregat River, NE Spain) and their relationship with hydrological conditions
2012
INTRODUCTION: Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain). METHODS: River fresh water samples were collected twice a week over a period of 5 weeks at three sampling points. Sixty-six pharmaceutical compounds belonging to different therapeutical classes were analyzed by LC-MS/MS. RESULTS AND DISCUSSION: Positive and negative correlations between the concentrations of the target analytes and hydrological variables like river flow and dissolved organic matter were observed pointing out the relevance of different hydrological phenomena like dilution effects or sediment re-suspension. Sensitivity calculations showed that the majority of compounds were sensitive to flow variations
Show more [+] Less [-]Reduction of dinitrotoluene sulfonates in TNT red water using nanoscale zerovalent iron particles
2012
PURPOSE: This research was designed to investigate the feasibility of converting the dinitrotoluene sulfonates (DNTS) in TNT red water into the corresponding aromatic amino compounds using nanoscale zerovalent iron (NZVI). METHODS: NZVI particles were simultaneously synthesized and stabilized by sodium borohydride reduction in a nondeoxygenated system. The morphology, elemental content, specific surface area, and crystal properties of the NZVI were characterized before and after the reaction by environmental scanning electron microscope; energy dispersive X-ray; Brunauer, Emmett, and Teller; and X-ray diffraction, respectively. The reduction process was conducted at pH = 6.3 at ambient temperature. The efficiency of the NZVI-mediated DNTS reduction process was monitored by HPLC, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses. RESULTS: The properties of the NZVI particles prepared were found to be similar to those obtained through oxygen-free preparation and inert stabilization processes. Both 2,4-DNT-3-sulfonate (2,220 mg L−1) and 2,4-DNT-5-sulfonate (3,270 mg L−1) in TNT red water underwent a pseudo-first-order transformation when mixed with NZVI at room temperature and near-neutral pH. Their observed rate constants were 0.11 and 0.30 min−1, respectively. Within 1 h of processing, more than 99% of DNTS was converted by NZVI-mediated reduction into the corresponding diaminotoluene sulfonates. CONCLUSIONS: NZVI can be simultaneously prepared and stabilized in a nondeoxygenated system. NZVI reduction is a highly efficient method for the conversion of DNTS into the corresponding diaminotoluene sulfonates under near-neutral pH conditions. Therefore, NZVI reduction may be useful in the treatment of TNT red water and subsequent recovery of diaminotoluene from explosive wastewater.
Show more [+] Less [-]Fallout traces of the Fukushima NPP accident in southern West Siberia (Novosibirsk, Russia)
2012
Melgunov, M. S. | Pokhilenko, N. P. | Strakhovenko, V. D. | Sukhorukov, F. V. | Chuguevskii, A. V.
BACKGROUND: The fallout of artificially produced radioactive isotopes has been recorded at a site in southern West Siberia (54°50′43.6″ N, 083°06′22.4″ E, Novosibirsk, Russia). DISCUSSION: The highest activities of 131I, 134Cs, and 136Cs were found in fresh snow precipitated on 02 April 2011, at 0.83, 0.092, and 0.002 Bq L−1 of meltwater, respectively. The 131I/134Cs ratio decreased from 9.0 on 02 April to 1.2 on 27 April, which is consistent with the radioactive decay of 131I. This fallout can only have originated from the accidental emission of Fukushima Nuclear Power Plant, Japan, in March 2011.
Show more [+] Less [-]Chemometric evaluation for the relation of BCR sequential extraction method and in vitro gastro-intestinal method for the assessment of metal bioavailability in contaminated soils in Turkey
2012
INTRODUCTION: A chemometric evaluation has been done to classify metal ions in soils and to determine whether or not the gastric and intestinal phases of a physiologically based extraction test bear any relation to any of the phases of the four-stage Community Bureau of Reference (BCR) extraction protocol. MATERIALS AND METHODS: Nine trace analytes (As, Ba, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were determined in extracts obtained from the BCR sequential extraction procedure as well as from in vitro gastro-intestinal experiments. The results showed that high As, Pb, Zn and Cd concentrations were found in these soils. Principal component analysis (PCA) and linear discriminant analysis were used as classification techniques. Stepwise multiple linear regression analysis was applied to the data set to determine how the bioaccessibility of a metal is linked to the operationally defined fractions of metal speciation in soil. RESULTS AND DISCUSSION: This analysis showed that the metal concentrations in the intestinal and gastric extracts are mainly dependent on the concentrations found in BCR phases 1 and 2 for each metal ion except for Cr, which was mainly dependent on the concentrations found in BCR phase 3. From the chemometric technique of correlation analysis, it was concluded that the metals extracted using BCR phases 1 and 2 are more likely to be bioaccessible, i.e. are also extracted by gastric and intestinal digestion solutions. When the correlation and PCA results were interpreted together, it indicated that the bioaccessiblity of Zn, Pb, Mn and Cd were higher than As, Ba, Cr, Ni and Cu for these soils.
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