Refine search
Results 2941-2950 of 5,151
Effects on Eichhornia crassipes under Zn stress Full text
2018
González, Cesar Iván | Maine, María Alejandra | Hadad, Hernán Ricardo | Sanchez, Gabriela Cristina | Benavides, María Patricia | Campagnoli, Marcelo Abel
Eichhornia crassipes is a macrophyte widely used in phytoremediation, demonstrating a high ability to remove metals from water. The aim of this work was to evaluate its enzymatic detoxification strategies and metal accumulation when it is exposed to different Zn concentrations (0, 2, 4, 6, and 9 ppm) for periods of 24, 48, and 72 h. Zn concentration in roots was significantly higher than in aerial parts. Independently of the treatment, in the first 48 h, concentrations of photosynthetic pigments were not affected. However, a significant increase (between 19 and 34%) in Chl-b concentrations for all treatments was observed at 72 h. Carotenoid concentration was not affected during the first 48 h, while at 72 h, there was a significant increase regarding the control (between 11 and 24%) for all treatments. Malondialdehyde concentration in aerial parts and roots was not affected during the experiment. Nonetheless, a significant increase in the enzymatic activity of the antioxidant system was observed. Results suggest that Zn could have potential antioxidant properties, which may result in the activation of different antioxidant enzymes involved in the protection against metal stress.
Show more [+] Less [-]Short-term biochar application induced variations in C and N mineralization in a compost-amended tropical soil Full text
2018
Jien, Shih-Hao | Chen, Wen-Chi | Ok, Yong Sik | Awad, Yasser Mahmoud | Liao, Chien-Sen
To mitigate food shortage due to global warming, developing sustainable management practices to stabilize soil organic matter (SOM) and sequester more carbon (C) in the cultivated soils is necessary, particularly in subtropical and tropical areas. A short-term (56 days) incubation experiment was conducted to evaluate the influences of rice husk biochar (RHB) and manure compost (MC) application on C mineralization and nitrogen (N) immobilization in a sandy loam soil. The RHB was separately incorporated into the soil at application rates of 2 and 4% (w/w) either with or without 1% (w/w) compost. Our results displayed that macroaggregates (≥2 mm) were obviously increased by 11% in soil amended with RHB + MC at the end of incubation. In addition, the experimental results presented that the C mineralization of the soil rapidly increased during the first week of incubation. However, the co-application of compost with biochar (RHB + MC) revealed that CO₂ emission was significantly decreased by 13–20% compared to the soil with only MC. In addition, the mineralized N in the soil was lower in RHB + MC-amended soil simultaneously than only MC-amended soil, indicating that biochar addition induced N immobilization. The physical protection of compost by its occlusion into aggregates or adsorption on surface of RHB as proved by the micromorphological observation was the main reason for lower C and N mineralization in soil amended with RHB + MC. Overall results revealed that RHB + MC treatment can decrease the decomposition of compost and sequester more C in the tropical agricultural soils.
Show more [+] Less [-]Different residue behaviors of four pesticides in mushroom using two different application methods Full text
2018
Du, Pengqiang | Wu, Xiaohu | Xu, Jun | Dong, Fengshou | Shi, Yingchun | Li, Yuanbo | Liu, Xingang | Zheng, Yongquan
Pesticide residue in mushrooms is less known. In this study, the risks of beta-cypermethrin, pyriproxyfen, avermectin, and diflubenzuron in oyster and shiitake mushrooms were evaluated using two different treatments: substrate mixture and surface spraying. Almost all the concentrations of these pesticides at day 90 were higher than 80% of the initial concentrations, while it was less than 45% for all cases within 35 days by spraying. For surface spraying, the residues of beta-cypermethrin were 0.0843–1.22 mg kg⁻¹ in shiitake mushrooms and below 0.005 mg kg⁻¹ in oyster mushrooms; the residues of pyriproxyfen, avermectin, and diflubenzuron were 0.122–4.84, 0.00501–0.111, and 0.0681–1.91 mg kg⁻¹, respectively. The residues of beta-cypermethrin, pyriproxyfen, and diflubenzuron in oyster mushrooms (in shiitake mushrooms) at interval of 0, 3, 5 days (1, 5, 7 days) were below their MRLs in China or Japan. The residue of avermectin in both mushrooms was lower than its limit of detection. These results provide information to safe and proper use of the pesticides in oyster and shiitake mushrooms.
Show more [+] Less [-]Metals in a northern Nile Delta lake: water, suspended particulates, sediments, and biota Full text
2018
Okbah, Mohamed A. | Abdelhalim, Ahmed M. | Abu El-Regal, Mohamed A. | Soliman, Naglaa F. | Nassar, Mohammed E. M.
Lake Edku is one of the important fishing areas in the Nile Delta. It is exposed to different quantities of serious pollutants in particular metals. To overall appraise the risk and status of metals in the lake, a comprehensive study of total concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in sediments and spatial-temporal variations of these metals in the dissolved and suspended particulates, and some tissues of Tilapias niloticus, was conducted from ten sampling sites during 2016. Results showed that none of the investigated metals exceeded the limits considered as hazardous for aquatic life in water. The highest concentrations of Cd, Cu, Ni, and Zn were observed in suspended particulate matter, which may precipitate on the surface of the sediments. Potential ecological risk analysis of the majority of the investigated metals in the sediment indicated that Lake Edku posed a low ecological risk. The estimated values of all metals in tissues of Tilapia niloticus were below the international permissible limits. Moreover, the potential risk of metals to human via the consumption of Tilapia niloticus was estimated using the weekly intake levels, which was lower than the WHO’s safe provisional tolerant weekly intake levels. These results prove the importance of performing measurements of contaminants in various compartments of Lake Ecosystem including sediment, biota, and suspended particulate matter for proper management.
Show more [+] Less [-]Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.) Full text
2018
Drąg-Kozak, Ewa | Socha, Magdalena | Gosiewski, Grzegorz | Łuszczek-Trojnar, Ewa | Chyb, Jarosław | Popek, Wlodzimierz
Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.) Full text
2018
Drąg-Kozak, Ewa | Socha, Magdalena | Gosiewski, Grzegorz | Łuszczek-Trojnar, Ewa | Chyb, Jarosław | Popek, Wlodzimierz
The aim of this study was to determine whether melatonin (Mel), which is a known antioxidant and free radical scavenger, could perform the role of a preventive agent against the toxic effects of cadmium (Cd²⁺) on mortality, fish growth, gonadosomatic index (GSI), luteinizing hormone (LH) secretion, the response to hormonal stimulation of spawning, and also tissue accumulation of Cd in Prussian carp females. These females received melatonin implants and were exposed to 0.4 or 4.0 mg/L of Cd (as CdCl₂·2.5H₂O) over either a 5- or 3-month period, followed by further 2 months of purification in clear water. Negative changes caused by exposure to cadmium in the water were as follows: higher fish mortality, lower body weight, increased accumulation of cadmium in the brain and ovary, lowered GSI, impaired spontaneous LH secretion during exposure, and impaired LH secretion during stimulation of spawning. All of these effects were observed in the group of fish exposed to 0.4 and/or 4.0 mg Cd/L but did not occur or were less pronounced in the groups exposed to cadmium in the presence of melatonin released from the implants. During depuration, in the group of fish which had been exposed to the highest Cd concentration, we observed a significant improvement in fish survival rate, body growth, inhibition of further cadmium accumulation in tissues, and gradual return of spontaneous LH secretion as well as normalization of the GSI value to the control group levels. In conclusion, these findings indicate that melatonin can be a preventive agent for some toxic effects on fish reproduction induced by environmental cadmium contamination.
Show more [+] Less [-]Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.) Full text
Ewa Drąg-Kozak | Magdalena Socha | Grzegorz Gosiewski | Ewa Łuszczek-Trojnar | Jarosław Chyb | Włodzimierz Popek
The aim of this study was to determine whether melatonin (Mel), which is a known antioxidant and free radical scavenger, could perform the role of a preventive agent against the toxic effects of cadmium (Cd2+) on mortality, fish growth, gonadosomatic index (GSI), luteinizing hormone (LH) secretion, the response to hormonal stimulation of spawning, and also tissue accumulation of Cd in Prussian carp females. These females received melatonin implants and were exposed to 0.4 or 4.0 mg/L of Cd (as CdCl2·2.5H2O) over either a 5- or 3-month period, followed by further 2 months of purification in clear water. Negative changes caused by exposure to cadmium in the water were as follows: higher fish mortality, lower body weight, increased accumulation of cadmium in the brain and ovary, lowered GSI, impaired spontaneous LH secretion during exposure, and impaired LH secretion during stimulation of spawning. All of these effects were observed in the group of fish exposed to 0.4 and/or 4.0 mg Cd/L but did not occur or were less pronounced in the groups exposed to cadmium in the presence of melatonin released from the implants. During depuration, in the group of fish which had been exposed to the highest Cd concentration, we observed a significant improvement in fish survival rate, body growth, inhibition of further cadmium accumulation in tissues, and gradual return of spontaneous LH secretion as well as normalization of the GSI value to the control group levels. In conclusion, these findings indicate that melatonin can be a preventive agent for some toxic effects on fish reproduction induced by environmental cadmium contamination. | Melatonin, Cadmium, LH, Bioaccumulation, Depuration, Prussian carp | 30 | 9915-9927 | 10
Show more [+] Less [-]Do aeration conditions affect arsenic and phosphate accumulation and phosphate transporter expression in rice (Oryza sativa L.)? Full text
2018
Wu, Chuan | Wang, Qiongli | Xue, Shengguo | Pan, Weisong | Lou, Laiqing | Li, Daojun | Hartley, William
Widespread contamination of rice with arsenic (As) has revealed a major exposure pathway to humans. The present study aimed to investigate the effects of oxygen in the rhizosphere on phosphate (P) transporter (for arsenate transportation) expressions, on As and P accumulation and As speciation in four rice genotypes. Oxygenation marginally increased root and shoot length. Total As concentrations in rice roots were dramatically reduced following aeration compared to stagnant treatments (p < 0.001). Aeration treatments significantly increased arsenate while reducing arsenite concentrations in roots (p < 0.001). Root arsenite concentrations were 1.5–2.5 times greater in stagnant than in aeration treatments. Total P concentrations in rice roots were dramatically increased following aeration compared to stagnant treatments. The relative abundance of phosphate transporter (inorganic phosphate transporter and phosphate/H⁺ symporter family protein) expressions showed downregulation in aeration treatments, particularly for SY-9586, XWX-17, and XWX-12 in inorganic phosphate transporter expressions and XWX-17 in phosphate/H⁺ symporter family protein expression (p < 0.05). The relative abundance of phosphate carrier protein expressions were relatively higher than the other phosphate transporters, showing upregulation in aeration treatments.
Show more [+] Less [-]In vitro elicitation, isolation, and characterization of conessine biomolecule from Holarrhena antidysenterica (L.) Wall. callus and its larvicidal activity against malaria vector, Anopheles stephensi Liston Full text
2018
Kumar, Dinesh | Kumar, Gaurav | Das, Ram | Ravindra Kumar, | Agrawal, Veena
In vitro elicitation of an important compound conessine has been done in the bark-derived callus culture of Holarrhena antidysenterica (L.) Wall. employing different elicitors. For induction of callus, green bark explants excised from field-grown plants were cultured on MS medium augmented with different concentrations (0, 1, 2.5, 5, and 10 μM) of various growth regulators such as BA, IBA, NAA, and 2,4-D either alone or in combinations. The maximum amount of conessine (458.18 ± 0.89ᵈ μg/g dry wt.) was achieved in callus developed on MS medium supplemented with 5 μM BA and 5 μM 2,4-D through HPLC analysis. Elicitation in conessine content in the above callus was achieved employing a variety of organic (phenylalanine, tyrosine, chitosan, tryptophan, casein hydrolysate, proline, sucrose, and yeast extract) as well as inorganic elicitors (Pb(NO₃)₂, As₂O₃, CuSO₄, NaCl, and CdCl₂) in different concentrations. The optimum enhancement in conessine content (3518.58 ± 0.28ᵍ μg/g dry wt.) was seen at the highest concentration (200 mg/L) of phenylalanine. The enhancement was elicitor specific and dose dependent. The overall increment of the conessine content was seen in the order of phenylalanine > tryptophan > Pb(NO₃)₂ > sucrose > NaCl > As₂O₃ > casein hydrolysate > CdCl₂ > chitosan > proline > yeast extract > CuSO₄ > tyrosine. The isolation and purification of conessine was done using methanol as a solvent system through column chromatography (CC) and TLC. The isolated compound was characterized by FT-IR, ¹H-NMR, and HRMS which confirmed with the structure of conessine. The bioassays conducted with the isolated compound revealed a strong larvicidal activity against Anopheles stephensi Liston with LC₅₀ and LC₉₀ values being 1.93 and 5.67 ppm, respectively, without harming the nontarget organism, Mesocyclops thermocyclopoides Harada, after 48 h of treatment. This is our first report for the isolation and elicitation of conessine in the callus culture of H. antidysenterica.
Show more [+] Less [-]Simultaneous purifying of Hg0, SO2, and NOx from flue gas by Fe3+/H2O2: the performance and purifying mechanism Full text
2018
Xing, Yi | Li, Liuliu | Lu, Pei | Cui, Jiansheng | Li, Qianli | Yan, Bojun | Jiang, Bo | Wang, Mengsi
Hg⁰, SO₂, and NOx result in heavily global environmental pollution and serious health hazards. Up to now, how to efficiently remove mercury with SO₂ and NOx from flue gas is still a tough task. In this study, series of high oxidizing Fenton systems were employed to purify the pollutants. The experimental results showed that Fe³⁺/H₂O₂ was more suitable to purify Hg⁰ than Fe²⁺/H₂O₂ and Cu²⁺/H₂O₂. The optimal condition includes Fe³⁺ concentration of 0.008 mol/L, Hg⁰ inlet concentration of 40 μg/m³, solution temperature of 50 °C, pH of 3, H₂O₂ concentration of 0.7 mol/L, and O₂ percentage of 6%. When SO₂ and NOx were taken into account under the optimal condition, Hg⁰ removal efficiency could be enhanced to 91.11% while the removal efficiency of both NOx and SO₂ was slightly declined, which was consistent to the analysis of purifying mechanism. The removal efficiency of Hg⁰ was stimulated by accelerating the conversion of Fe²⁺ to Fe³⁺, which resulted from the existence of SO₂ and NOx. The results of this study suggested that simultaneously purifying Hg⁰, SO₂, and NOx from flue gas is feasible.
Show more [+] Less [-]Bayesian inference for the genetic control of water deficit tolerance in spring wheat by stochastic search variable selection Full text
2018
Safari, Parviz | Danyali, Syyedeh Fatemeh | Raḥīmī, Mahdī
Drought is the main abiotic stress seriously influencing wheat production. Information about the inheritance of drought tolerance is necessary to determine the most appropriate strategy to develop tolerant cultivars and populations. In this study, generation means analysis to identify the genetic effects controlling grain yield inheritance in water deficit and normal conditions was considered as a model selection problem in a Bayesian framework. Stochastic search variable selection (SSVS) was applied to identify the most important genetic effects and the best fitted models using different generations obtained from two crosses applying two water regimes in two growing seasons. The SSVS is used to evaluate the effect of each variable on the dependent variable via posterior variable inclusion probabilities. The model with the highest posterior probability is selected as the best model. In this study, the grain yield was controlled by the main effects (additive and non-additive effects) and epistatic. The results demonstrate that breeding methods such as recurrent selection and subsequent pedigree method and hybrid production can be useful to improve grain yield.
Show more [+] Less [-]Long non-coding RNA CASC15 promotes tongue squamous carcinoma progression through targeting miR-33a-5p Full text
2018
Zuo, Zhibin | Ma, Long | Gong, Zuode | Xue, Lande | Wang, Qibao
Long non-coding RNAs (lncRNAs) have gained a lot of attention because they participate in several human disorders, including tumors. This study determined the role of LncRNA CASC15 (cancer susceptibility candidate 15) in the development of tongue squamous cell carcinoma (TSCC). Here, we identified that CASC15 expression was upregulated in TSCC samples and cell lines. We showed that overexpression of CASC15 promoted cell proliferation, cycle, and migration in TSCC. In addition, we revealed that miR-33a-5p expression was downregulated in TSCC tissues and cell lines. Moreover, we showed that the expression of CASC15 was negatively related with miR-33a-5p expression in TSCC tissues. Ectopic expression of miR-33a-5p suppressed cell proliferation, cycle, and migration in TSCC. Elevated expression of CASC15 suppressed miR-33a-5p expression and promoted ZEB1 expression in SCC4 cell. Ectopic expression of CASC15 promoted TSCC cell proliferation, cycle, and migration through targeting miR-33a-5p. These results suggested that lncRNA CASC15 and miR-33a-5p might be exploited as new markers of TSCC and were potential treatment targets for TSCC patients.
Show more [+] Less [-]