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1.
Manganese (Mn) is a trace element known to be essential for maintaining the proper function and regulation of many biochemical and cellular reactions. However, little is known about the effect of excessive amounts of Mn in immune damage of birds. The aim of this study was to investigate the effect of dietary Mn on immune damage in birds. 50-day-old male Hy-line cocks were fed either a commercial diet or a Mn-supplemented diet containing 600, 900, and 1800 mg kg ?1 MnCl 2. After being treated with Mn for 30, 60 and 90 d, the serum and immune organs (spleen, thymus, and bursa of Fabricius (BF)) were collected respectively and examined for Mn contents, activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), malondialdehyde (MDA) contents, ability to resist OH . In addition, DNA damage and apoptosis were observed in cock immune system treated with Mn. The results showed that the contents of Mn and MDA in immune organs and serum were increased, while the activities of SOD, GSH-Px, and ability to resist OH were decreased in the Mn treatment groups. The extensive damage was observed in the immune organs. DNA single strand break and DNA–protein crosslink showed time and dosage effect in lymphocytes of immune organs. It indicated that Mn exposure resulted in oxidative damage of birds immune system by altering antioxidant defense enzyme systems, lipid peroxidation, and apoptosis. 相似文献
3.
A mixture of pyrethroids plus organophosphates was assessed for their potential effects on lipid peroxidation, the antioxidant defense system and lactate dehydrogenase (LDH) in rat kidney in vitro. Various insecticide concentrations were incubated with kidney homogenate at 37°C for different incubation times. Treatment with fenitothion (FNT) plus lambda-cyhalothrin (LC) caused a significant induction ( P < 0.05) in thiobarbituric acid reactive substances (TBARS), which might be associated to decreased levels of reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) activities and protein content in rat kidney. However, a significant induction of lactate dehydrogenase (LDH) activity was observed. The effect was concentration and time dependent. It can be concluded that depletion of GSH might indicate that reactive oxygen species (ROS) could be involved in the toxic effects of FNT plus LC which lead to marked perturbations in antioxidant defense system. 相似文献
4.
Roundup® is a glyphosate-based herbicide containing a mixture of surfactants. This paper evaluates the toxic effects of Roundup® and its main constituents on the goldfish, Carassius auratus, after 7 days exposure. Fish were exposed to 0.16, 0.032 and 0.0064 mg/L of Roundup® [containing 41% isopropylamine salt of glyphosate (G.I.S) and 18% polyoxyethylene amine (POEA)], G.I.S, and POEA. Their livers were taken for determining reactive oxygen species (ROS), superoxide dismutase (SOD) activity, malondialdehye (MDA) content and acetylcholinesterase (AChE) activity. Hydroxyl radical (·OH) could be induced by exposing Roundup® at a rate of 43%–111%, G.I.S at 90%–124% and POEA at142%–157%. A decreased SOD activity was observed in fish exposed to G.I.S and POEA. The contents of MDA significantly increased when exposed to Roundup® at all concentrations, 0.16 mg/L G.I.S and 0.032 mg/L POEA. The exposure led to an inhibition of AChE in livers overall during the experimental periods. POEA was more toxic than Roundup® or G.I.S during this experiment. AChE and ·OH are supposed to be sensitive biomarkers of the exposure of Roundup® and its main constituents to C. auratus. 相似文献
5.
Pennisetum sp. was employed as a model species to detect the growth and physiological response to cadmium (Cd) stress at different Cd concentrations (0, 20, 50, and 100 mg kg−1) in three types of soils (yellow brown soil, yellow soil, and red soil). Results showed that the growth of Pennisetum sp. was not significantly influenced by Cd in 20 mg kg−1, but significantly inhibited at higher Cd concentrations in three types of soils. Besides, the higher Cd concentrations, the lower root, stem, and leaf biomass. With Cd concentration of soil increasing, Cd content of root, stem, and leaf increased. Compared with no Cd, high Cd concentrations (50 and 100 mg kg−1) induced the physiological indices (photosynthetic rate, stomatal conductance, transpiration rate) and biochemical indices (nitrate reductase, glutamine synthetase, and glutamate synthase activities) decreasing, but the concentration of NO3− and NH4+ increasing. The activity of antioxidative enzymes (SOD, POD, and CAT) was disrupted and the content of malondialdehyde (MDA) increasing. Pennisetum sp. could protect cells from damage and maintain normal physiological metabolism via increasing the production of soluble sugar and soluble protein, but soluble proteins and soluble sugars were limited in high concentrations of Cd (50 and 100 mg kg−1). Moreover, the growth and physiological response to Cd are different in the three types of soils. The growth of Pennisetum sp. in yellow brown soil was better than that in other two soils, and the gas exchange rate, antioxidant enzyme activity, and nitrogen metabolism in yellow soil and red soil were more affected by Cd stress than that in yellow brown soil. Overall, Pennisetum sp. had certain tolerance and biosorption ability to Cd in different Cd concentrations and different types of soil. Hence, Pennisetum sp. was a suitable choice for Cd remediation, especially in yellow brown soil. 相似文献
6.
Rates of CO 2 production in the reaction CO + OH and CO + OH + halocarbon have been used to determine rate constants for some OH + halocarbon reactions at 29.5°C relative to that of k(CO + OH) = 2.69 × 10 ?13 cm 3 molecule ?1 sec ?1. The following rate constants were obtained: k(OH + CH 3Cl) = 3.1 ± 0.8, k(OH + CH 2Cl 2) = 2.7 ± 1.0, k(OH + C 2H 5Cl) = 44.0 ± 25, k(OH + CICH 2CH 2CI) = 6.5, (<29) and k(OH + CH 3CCl 3) = 2.1 (<5.7) cm 3 molecule ?1 sec ?1 × 10 ?14. The k values, CH 2Cl 2 excepted, are in substantial agreement with determinations made in nonoxygen environments. The present results for CH 2Cl 2 are almost certainly in error due to difficulties with the competitive approach used. 相似文献
7.
ABSTRACT Water is effective in leaching out Cr 6+ from a mixture of paint powders and abrasive blast media. However, acids such as HNO 3, HCl, and H 2SO 4 significantly enhance the leaching procedure. Cr ions in the leaching solutions are successfully removed by electrochemical precipitation. The consumable Fe electrodes generate ferrous ions to cause the reduction of Cr 6+ to Cr 3+. Cr 3+ ions along with Fe 2+ and Fe 3+ are then removed mainly by precipitation as Cr(OH) 3, Fe(OH) 2, and Fe(OH) 3 near the cathode where OH - ions are generated by water electrolysis. The electrochemical process is capable of discharging low levels of Cr 6+, less than 1 mg/L, without pH adjustment. 相似文献
8.
In this study, crucian carp (Carassius auratus) was exposed to the increasing concentrations of municipal sewage treatment plant effluent (MSTPE) for 15 days, and the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and acetylcholinesterase (AChE), together with the contents of malondialdehyde (MDA) and glutathione (GSH) in the liver of C. auratus were investigated. Moreover, the integrated biomarker response (IBR) approach was applied to assess the adverse effects of MSTPE in freshwater. The aim of the study was to provide an effective biological indicator for evaluating the toxicity effects and ecological risks of MSTPE in the freshwater environment quantitatively. Results showed that MSTPE could cause oxidative damage to the liver of C. auratus, which reflected through the increasing MDA content over the exposure period. MSTPE also led to the biochemical responses of antioxidant defense in C. auratus liver, such as the enhancement of SOD, CAT, and GPx activities, as well as the inhibition of AChE activity and GSH content. It was found that MDA, SOD, GPx, and GSH could be used as the biomarkers for reflecting the adverse effects of MSTPE in the receiving freshwater on the 12th day of exposure. A significant increase of IBR values was observed as the increasing concentration of MSTPE, and the IBR values presented a significant positive correlation (r?=?0.891, P?<?0.05) with the increasing concentrations of MSTPE, indicating that IBR approach is a promising tool for assessing the toxicity effects of MSTPE in environmental freshwater. 相似文献
9.
The aquatic plant Pistia stratiotes L. (water lettuce) was studied due to its capability of absorption of contaminants in water and its subsequent use in wetlands constructed for wastewater treatment. The effects of Cd on root growth, accumulation of Cd, antioxidant enzymes, and malondialdehyde (MDA) content in P. stratiotes were investigated. The results indicated that P. stratiotes has considerable ability to accumulate Cd. Cadmium induced higher superoxide dismutase (SOD) and peroxidase (POD) activities than catalase activity, suggesting that SOD and POD provided a better defense mechanism against Cd-induced oxidative damage. The accumulation of Cd promoted MDA production. 相似文献
10.
Previously, we demonstrated that maternal exposure to high, intermediate, or lowly contaminated European eels with a mixture of chemicals, during pregnancy and lactation, resulted in adult despair-like behavior, selectively in male offspring mice. Here, we investigate if depression-like behavior in offspring males was transient or permanent by monitoring immobility behavior, a measure of behavioral despair, at three distinct stages of life, including young adult (post-natal day (PND) 55), mature adult (PND 200) and middle (PNDs 335–336) age, in the forced swimming (FST) and the tail suspension (TST) tests. Oxidative stress markers including malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were evaluated in the hippocampus, prefrontal cortex, and cerebellum of middle-aged animals. Findings showed a significant enhancement of immobility behavior in the TST performed at young adult age (all p < 0.05) in the FST carried out at mature adult age (all p < 0.001) and in both behavioral tests realized at middle age (all p < 0.05, except one p = 0.06) in mice perinatally exposed to eels compared with non-exposed controls. Antioxidant-related enzyme activities, including SOD and CAT, were only elevated in the hippocampus of middle-aged males perinatally exposed to the two more polluted eels (all p < 0.05). Further, lipid peroxidation, assessed by MDA levels, was not found to be differentially regulated in the selected areas of middle-aged brains of exposed mice (all p > 0.05). Collectively, this suggested limited oxidative metabolism disturbances in middle-aged brains exposed to eels. In summary, our results highlighted that offspring males perinatally exposed to naturally contaminated reared and river eels with persistent organic pollutants (POPs) and heavy metals displayed chronic depression-like phenotype. As extrapolation of data to humans should be done with precaution, retrospective and prospective epidemiological studies are needed to clarify this potential relationship, stressed in our animal model, between maternal polluted fish consumption and chronically low mood in offspring. 相似文献
11.
The effects and associated toxicological mechanisms of five phthalate esters (PAEs) on abalone embryonic development were investigated by exposing the embryos to a range of PAEs concentrations (0.05, 0.2, 2 and 10 μg/mL). The results showed that PAEs could significantly reduce embryo hatchability, increase developmental malformations, and suppress the metamorphosis of abalone larvae. The possible toxicological mechanisms of PAEs to abalone embryos included, affecting the Na +-K +-pump and Ca 2+-Mg 2+-pump activities, altering the peroxidase (POD) level and the malondialdehyde (MDA) production, damaging the extraembryonic membranes structure, as well as disrupting endocrine-related genes ( gpx, cyp3a, and 17β-hsd 12) expression properties. Taken together, this work showed that PAEs adversely affected the embryonic ontogeny of abalone. The abilities of PAEs affecting the osmoregulation, inducing oxidative stress, damaging embryo envelope structure, and causing physiological homeostasis disorder, are likely to be a part of the common mechanisms responsible for their embryonic toxicity. 相似文献
12.
This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride–induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L?1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L?1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg?1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride–induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride–induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride–induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens. 相似文献
13.
Abstract The effects of divalent cations on gluconeogenesis in enzy‐matically isolated rat hepatic parenchymal cells were examined. Cadmium, zinc and copper decreased glucose production from lactate (10 mM). However, manganese at 0.05 to 1.0 mM levels stimulated gluconeogenesis by the cells and reduced the effects of the Cd +2, Zn +2 and Cu +2 on gluconeogenesis. The results indicate that under these in vitro conditions the cations altered an aspect of hepatic function—gluconeogenesis from lactate. 相似文献
14.
The oxidation capacity of the highly polluted urban area of Santiago de Chile has been evaluated during a winter measurement campaign from May 25 to June 07, 2005, with the results compared and contrasted with those previously evaluated during a summer campaign from March 8 to 20, 2005. The OH radical budget was evaluated in both campaigns employing a simple quasi-photostationary state model (PSS) constrained with simultaneous measurements of HONO, HCHO, O 3, NO, NO 2, j(O 1D), j(NO 2), 13 alkenes and meteorological parameters. In addition, a zero dimensional photochemical box model based on the Master Chemical Mechanism (MCMv3.1) has been used for the analysis of the radical budgets and concentrations of OH, HO 2 and RO 2. Besides the above parameters, the MCM model has been constrained by the measured CO and other volatile organic compounds (VOCs) including alkanes and aromatics. Total production and destruction rates of OH and HO 2 in winter are about two times lower than that during summer. Simulated OH levels by both PSS and MCM models are similar during the daytime for both winter and summer indicating that the primary OH sources and sinks included in the simple PSS model are predominant. On a 24 h basis, HONO photolysis was shown to be the most important primary OH radical source comprising 81% and 52% of the OH initiation rate during winter and summer, respectively followed by alkene ozonolysis (12.5% and 29%), photolysis of HCHO (6.1% and 15%), and photolysis of O 3 (<1% and 4%), respectively. During both winter and summer, there was a balance between the OH secondary production (HO 2 + NO) and destruction (OH + VOCs) showing that initiation sources of RO 2 and HO 2 are no net OH initiation sources. This result was found to be fulfilled also for all other studies investigated. Seasonal impacts on the radical budgets are also discussed. 相似文献
15.
The kinetics of OH oxidation of several organic compounds of atmospheric relevance were measured in the aqueous phase. Relative kinetics were performed using various organic references and OH sources. After validation of the protocol, temperature-dependent rate constants for the reactions of OH radical with ethyl ter-butyl ether (, Ea/ R=580 (±560) K), n-butyl acetate ( (±0.4)×10 9 M −1 s −1, Ea/ R=1000 (±200) K), acetone ( (±0.05)×10 9 M −1 s −1, Ea/ R=1400 (±500) K), methyl ethyl ketone (, Ea/ R=1200 (±200) K), methyl iso-butyl ketone (, Ea/ R=1200 (±300) K) and methylglyoxal (, Ea/ R=1100 (±300) K) were determined. A non-Arrhenius behavior was found for phenol, in good agreement with the contribution of an OH addition to the mechanism, which also includes H-abstraction by OH radicals. Global rate constants of acetaldehyde, propionaldehyde, butyraldehyde and valeraldehyde were studied at 298 K only, as these compounds partly hydrate in the aqueous phase. All the obtained data (except those of phenol) complemented by literature data were used to investigate three methods to estimate rate constants for H-abstraction reactions of OH radicals in aqueous solutions when measured data were not available: Evans-Polanyi-type correlations, comparisons with gas-phase data, structure activity relationships (SAR). The results show that the SAR method is promising; however, the data set is currently too small to extend this method to temperatures other than 298 K. The atmospheric impact of aqueous phase OH oxidation of water-soluble organic compounds is discussed with the determination of their global atmospheric lifetimes, taking into account both gas- and aqueous-phase reactivities. The results show that atmospheric droplets can act as powerful photoreactors to eliminate soluble organic compounds from the atmosphere. 相似文献
16.
In order to remove high concentrations of hydrogen sulfide (H 2S) gas from anaerobic wastewater treatments in livestock farming, a novel process was evaluated for H 2S gas abatement involving the combination of chemical absorption and biological oxidation processes. In this study, the extensive experiments evaluating the removal efficiency, capacity, and removal characteristics of H 2S gas by the chemical absorption reactor were conducted in a continuous operation. In addition, the effects of initial Fe 2 + concentrations, pH, and glucose concentrations on Fe 2 + oxidation by Thiobacillus ferrooxidans CP9 were also examined. The results showed that the chemical process exhibited high removal efficiencies with H 2S concentrations up to 300 ppm, and nearly no acclimation time was required. The limitation of mass‐transfer was verified as the rate‐determining step in the chemical reaction through model validation. The Fe 2 + production rate was clearly affected by the inlet gas concentration as well as flow rate and a prediction equation of ferrous production was established. The optimal operating conditions for the biological oxidation process were below pH 2.3 and 35°C in which more than 90% Fe 3 + formation ratio was achieved. Interestingly, the optimal glucose concentration in the medium was 0.1%, which favored Fe 2 + oxidation and the growth of T. ferrooxidans CP9. 相似文献
17.
This study aims to develop a high-efficiency radical oxidation process for enhancing the dewaterability of waste activated sludge (WAS). Radical scavenging studies combined with electron paramagnetic resonance (EPR) were carried out for the direct radical identification and effectiveness evaluation of radical oxidation. The results indicated that Fe(II)-activated CaO 2 can pose a superior effect on dewatering WAS due to its distinctive capacity of stable ?OH production and the high reaction efficiency of regulated-released ?OH with water-holding organics. The mechanism for the enhanced dewatering performance was also explored. The rupture of sludge colloidal flocs and the reduction of hydrophilic functional groups in loosely bound extracellular polymeric substances (LB-EPS) were found to be mainly responsible for the release of interstitial water and improved dewaterability, respectively. In addition, an inference about the relationship between interfacial water and zeta potential of different EPS fractions was established by the simultaneous measurement of the binding affinities of Ca 2+ and Fe 2+/Fe 3+ for EPS and bound water content. All these results provide the direct evidence that Fe(II)-activated CaO 2 is a promising pretreatment reagent for sludge disposal. Implications: Fe(II)-activated CaO 2 was first proposed to be highly effective in enhancing the dewaterability of waste activated sludge. Electron paramagnetic resonance (EPR) spectroscopy provided the direct evidence for the specific advantages of CaO 2, especially the capacity of durable and efficacious ?OH production leading to the excellent conditioning performance. 相似文献
18.
We present one of the most comprehensive studies of night-time radical chemistry to date, from the Tropospheric ORganic CHemistry experiment (TORCH) in the summer of 2003. TORCH provided a wealth of measurements with which to study the oxidizing capacity of the atmosphere. The measurements provided input to a zero-dimensional box model which has been used to study night-time radical chemistry during the campaign. Average night-time predicted concentrations of OH (2.6 × 10 5 molecule cm ?3), HO 2 (2.9 × 10 7 molecule cm ?3) and [HO 2+ΣRO 2] radicals (2.2 × 10 8 molecule cm ?3) were an order of magnitude smaller than those predicted during the daytime. The model under-predicted the night-time measurements of OH, HO 2 and [HO 2+ΣRO 2] radicals, on average by 41%, 16% and 8% respectively. Whilst the model captured the broad features of night-time radical behaviour, some of the specific features that were observed are hard to explain. A rate of radical production assessment was carried out for the whole campaign between the hours of 00:00 and 04:00. Whilst radical production was limited owing to the absence of photolytic reactions, production routes via the reactions of alkenes with O 3 provided an effective night-time radical source. Nitrate radical concentrations were predicted to be 0.6 ppt on average with a peak of 18 ppt on August 9th during a polluted heat wave period. Overall, the nitrate radical contributes about a third of the total initiation via RO 2, mostly through reaction with alkenes. 相似文献
19.
An observation-based method (OBM) is developed to evaluate the ozone (O 3) production efficiency (O 3 molecules produced per NO x molecule consumed) and O 3 production rate ( P(O 3)) during a field campaign in southern Taiwan. The method can also provide an estimate of the concentration of OH. A key step in the method is to use observed concentrations of two aromatic hydrocarbons, namely ethylbenzene and m, p-xylene, to estimate the degree of photochemical processing and amounts of photochemically consumed NO x and NMHCs by OH. In addition, total oxidant (O 3+NO 2) instead of O 3 itself turns out to be very useful for representing ozone production in the OBM approach. The average O 3 production efficiency during the field campaign in Fall (2003) is found to be about 10.2±3.9. The relationship of P(O 3) with NO x is examined and compared with a one-dimensional (1D) photochemical model. Values of P(O 3) derived from the OBM are slightly lower than those calculated in the 1D model. However, OH concentrations estimated by the OBM are about a factor of 2 lower than the 1D model. Fresh emissions, which affect the degree of photochemical processing appear to be a major cause of the underestimate. We have developed a three-dimensional (3D) OBM O 3 production diagram that resembles the EKMA ozone isopleth diagram to study the relationship of the total oxidant versus O 3 precursors. The 3D OBM O 3 production diagram suggests that reducing emissions of NMHCs are more effective in controlling O 3 than reducing NO x. However, significant uncertainties remain in the OBM, and considerable more work is required to minimize these uncertainties before a definitive control strategy can be reached. The observation-based approach provides a good alternative to measuring peroxy radicals for evaluating the production of O 3 and formulating O 3 control strategy in urban and suburban environments. 相似文献
20.
A method is presented for determining production and consumption rates of .OH radicals produced photochemically in natural surface waters. It is based on the determination of the kinetics by which the concentration of a specified trace compound decreases during irradiation. In samples from Lake Greifensee (Switzerland) low production rates for .OH limit its possible effects. In addition, fast consumptions by the natural dissolved organic solutes and by the bicarbonate protect organic micropollutants from oxidation by .OH. Neither direct nor indirect H 2O 2 photolysis was a significant source of .OH in the lakewater studied lacking iron, whereas nitrate photolysis could have been a source. Comparison with reaction kinetic formulations allows generalizations for other types of waters. 相似文献
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