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Результаты 4841-4850 из 6,560
Does ozone exposure affect herbivore-induced plant volatile emissions differently in wild and cultivated plants? Полный текст
2020
Brosset, Agnès | Saunier, Amélie | Kivimäenpää, Minna | Blande, James D.
Concentrations of tropospheric ozone have more than doubled in the Northern Hemisphere since pre-industrial times. Plant responses to single abiotic or biotic stresses, such as ozone exposure and herbivore-feeding, have received substantial attention, especially for cultivated plants. Modern cultivated plants have been subjected to selective breeding that has altered plant chemical defences. To understand how ozone might affect plant responses to herbivore-feeding in wild and cultivated plants, we studied the volatile emissions of brassicaceous plants after exposure to ambient (~ 15 ppb) or elevated ozone (80 ppb), with and without Plutella xylostella larvae-feeding. Results indicated that most of the wild and cultivated plants increased volatile emissions in response to herbivore-feeding. Ozone alone had a weaker and less consistent effect on volatile emissions, but appeared to have a greater effect on wild plants than cultivated plants. This study highlights that closely related species of the Brassicaceae have variable responses to ozone and herbivore-feeding stresses and indicates that the effect of ozone may be stronger in wild than cultivated plants. Further studies should investigate the mechanisms by which elevated ozone modulates plant volatile emissions in conjunction with biotic stressors.
Показать больше [+] Меньше [-]DNA methylation of JAK3/STAT5/PPARγ regulated the changes of lipid levels induced by di (2-ethylhexyl) phthalate and high-fat diet in adolescent rats Полный текст
2020
Xu, Qi | Qi, Wen | Zhang, Yuezhu | Wang, Qi | Ding, Shuang | Han, Xu | Zhao, Yaming | Song, Xinyue | Zhao, Tianyang | Zhou, Liting | Ye, Lin
Di (2-ethylhexyl) phthalate (DEHP) and high-fat diet (HFD) could induce lipid metabolic disorder. This study was undertaken to identify the effect of DNA methylation of JAK3/STAT5/PPARγ on lipid metabolic disorder induced by DEHP and HFD. Wistar rats were divided into a normal diet (ND) group and HFD group. Each diet group treated with DEHP (0, 5, 50, 500 mg/kg/d) for 8 weeks’ gavage. The DNA-methylated levels of PPARγ, JAK3, STAT5a, and STAT5b in rats’ livers and adipose were analyzed with MethylTarget. The lipid levels of rats’ livers and adipose were detected with ELISA. Results showed in ND group that the DNA methylation levels of PPARγ, JAK3 in livers, and STAT5b in adipose were lower in 500 mg/kg/d group than the control. And the level of total cholesterol (TC) in adipose was higher in 500 mg/kg/d group than the control. In HFD group, the DNA methylation level of JAK3 was the lowest in livers and the highest in adipose in 50 mg/kg/d group. And the level of TC in livers was the lowest in 50 mg/kg/d group. In the 500 mg/kg/d group, the DNA methylation level of STAT5b was lower in livers and higher in adipose in HFD group than that in ND group. And the levels of TC in livers were lower in HFD group than those in ND group. Therefore, DNA methylation of JAK3/STAT5/PPARγ regulated the changes in lipid levels induced by DEHP and HFD in adolescent rats.
Показать больше [+] Меньше [-]Norm index-based QSPR model for describing the n-octanol/water partition coefficients of organics Полный текст
2020
Jia, Qingzhu | Shi, Qiyu | Yan, Fangyou | Wang, Qiang
The n-octanol/water partition coefficient (logKₒw) is widely used in the environmental, agricultural and pharmaceutical fields for the risk evaluation and application of organic chemicals. In this work, grounded on atomic distribution matrices, a norm index-based QSPR model was built for organic chemicals with 18 kinds of diverse structures. The statistical results (R² = 0.9037, RMSE = 0.4515) showed that the QSPR model for describing the logKₒw of organics was fitted well. Various validation results showed that the model had good robustness, good predictability and wide applicability. These satisfactory results indicated that the model was applicable for the logKₒw description of organic chemicals and that norm descriptors were reliable and general for the description of organic structures. The model was relatively better at describing logKₒw for aromatics, alcohols, nitriles, esters, amides, halogenated compounds, acids and amine compounds. The intensity of spatial branching and the space charge distribution intensity descriptors could have a greater impact on the logKₒw value of a compound.
Показать больше [+] Меньше [-]Evaluation of the catalytic oxidation of soot by CeOX-LaMnO3 at different O2 pressures synthesized by ultrasonic-assisted hydrothermal method Полный текст
2020
Moreno-Román, Eddy Jonatan | Cruz-López, Arquímedes | García-Gómez, Celestino | Zanella, Rodolfo | Suárez-Vázquez, Santiago Iván
In this work, the synthesis of catalyst with perovskite structure and chemical formula La₁₋XCeXMnO₃ at x = 0 − 0.5 were successfully obtained by an ultrasonic-assisted hydrothermal method. Results show that the addition of Ce in La₁₋XCeXMnO₃ have not substantial effect in textural and morphological properties; however, the formation of a new crystalline phase with final composition CeOX-La₁₋XCeXMnO₃ was detected at values x > 0.3. All synthesized catalysts were tested in the soot oxidation under both, loose and tight contact in 20% O₂/N₂ or 5% O₂/N₂ atmospheres. CeOX-La₁₋XCeXMnO₃ at x = 0.3 resulted in the best catalytic activity with activation energy values of 57.9 kJ.mol⁻¹. The interaction between Ce³⁺ and Mn⁴⁺ species in this catalyst can transfer electrons generating Mn³⁺ and Ce⁴⁺. This reduction from Mn⁴⁺ to Mn³⁺ is accompanied by migration of vacancies to the surface promoting the adsorbed oxygen from the gas phase, need for balancing the chemical states. By increasing the temperature above 300 °C, the bulk oxygen migration to the surface is enhanced being the responsible for the oxygen availability. The formation of CeOX-La₁₋XCeXMnO₃ promotes a stable redox cycle allowing the reusability of this catalyst even at low oxygen pressures after three different reaction cycles.
Показать больше [+] Меньше [-]The impact of airborne pollution and exposure to solar ultraviolet radiation on skin: mechanistic and physiological insight Полный текст
2020
Ali, Atif | Khan, Hira | Bahadar, Raheem | Riaz, Asma | Asad, Muhammad Hassham Hassan Bin
For several decades air pollution has been recognized to hit drastically the skin of human body. Air pollutants predominantly accountable for aging, oxidative damage, and inflammatory allergic reactions led to psoriasis, dermatitis, acne, and skin cancer owing to the impaired functions of DNA, proteins, and lipid biomolecules. Elevated air pollution and its detrimental effects along with variations in physiological parameters of the skin are verily the scaffold for anti-pollution assertions and could be recognized as markers. The present article encompasses the salient features of air pollution and UV radiations besides dreadful effects on human skin physiological parameters and some anti-pollution approaches.
Показать больше [+] Меньше [-]Groundwater environmental risk assessment of abandoned coal mine in each phase of the mine life cycle: a case study of Hongshan coal mine, North China Полный текст
2020
Feng, Haibo | Zhou, Jianwei | Chai, Bo | Zhou, Aiguo | Li, Jianzhong | Zhu, Henghua | Chen, Hongnian | Su, Danhui
Human activities during each phase of coal mine life cycle greatly affect groundwater environment. The groundwater environment destruction is not just only the destruction of underground structure but also the social problems caused by available groundwater resources reduction, as well as the environmental problems affecting ecosystem and human health. Moreover, the groundwater environmental risk of coal mining is complex, dynamic, and long-term. Therefore, a framework and quantitative method for groundwater environmental risk analysis at different phases of the mine life cycle was presented, which is composed of the groundwater system destruction risk (GSDR) and social-economic-ecological vulnerability (SEEV) assessment. The framework was applied in Hongshan abandoned coal mine, North China. Based on the aquifer structure destruction, groundwater flow field evolution, contamination, and social-economic influence analysis, 12 main controlling factors for the GSDR and 7 factors for the SEEV were determined and quantified separately. The results showed that the groundwater contamination of the Hongshan mine mainly occurred after closure, caused by the cross-strata pollution of mine water, which significantly reduced the groundwater available resources, which greatly affected local social-economy sustainable development and residents’ health. The Hongshan mine closure increased groundwater environmental risk, with the GSDR high-risk zone being 12.51 km² larger than that during the mining phase and the SEEV was calculated at a high level. This framework promotes systematic integration of the groundwater environmental risk assessment in mine life cycle.
Показать больше [+] Меньше [-]How agriculture, manufacture, and urbanization induced carbon emission? The case of Indonesia Полный текст
2020
Prastiyo, Slamet Eko | Irham, | Hardyastuti, Suhatmini | Jamhari,
The agriculture and manufacturing sectors are the backbones of the Indonesian economy; for this reason, research on the effects of these sectors on carbon emissions is an important subject. This work adds urbanization to enrich research on the Environmental Kuznets Curve (EKC) in Indonesia. The results of this study indicate that the EKC hypothesis was confirmed in Indonesia with a turning point of 2057.89 USD/capita. The research results show that all variables affect the escalation of greenhouse gas emissions in Indonesia. Furthermore, there is a bidirectional causality relationship between emissions with economic growth, emissions with agricultural sector, emissions with manufacturing sector, economic growth with agricultural sector, and economic growth with manufacturing. The unidirectional causality is found in emissions by urbanization and economic growth by urbanization. To reduce the impact of environmental damage caused by the activities of agriculture, manufacturing, and urbanization sectors, it is recommended that the government conduct water-efficient rice cultivation and increase the use of renewable energy.
Показать больше [+] Меньше [-]Source apportionment of black carbon and the feedback effect on the meteorological factors in Beijing, China Полный текст
2020
Wang, Wenwei | Ma, Xin | Guo, Chunwei | Wei, Peng | Zhao, Xiujuan | Xu, Jing
Black carbon (BC) is a major light-absorbing component in the atmosphere and plays an important role in aerosol radiative forcing. In this study, the combination of monitoring data and the WRF-Chem model was used to study the source apportionment of BC in China during January 2017. Meanwhile, the aerosol-radiation interaction (ARI) effect of BC was also simulated. We found that the average BC/PM₂.₅ ratios were 4.8%, 4.2%, and 3.8% in Shijiazhuang, Tangshan, and Beijing, respectively. The source apportionment suggested that traffic emissions played a dominant role in the BC concentration over Beijing. The traffic, residential, industrial, and power contributions accounted for 41%, 32%, 25%, and 2% of total concentration, respectively. The BC concentration in Beijing was also affected by regional transport. During January, the contributions of monthly regional transport to BC and PM₂.₅ concentrations in Beijing were 41% and 49%, respectively. BC emissions decreased downward shortwave radiation (SWDOWN) at the surface, leading to a decrease in temperature. As a result, the planetary boundary layer height (PBLH) development was suppressed and the relative humidity increased. The stable meteorological conditions suppressed the dispersion of air pollutants and increased BC concentrations. Traffic emissions decreased the monthly SWDOWN by approximately 2.2 W/m², decreased 2 m temperature (T2) by approximately 0.1 °C, increased 2 m relative humidity (RH2) by approximately 0.5%, and decreased PBLH by approximately 4.4 m.
Показать больше [+] Меньше [-]Update on the use of Pristina longiseta Ehrenberg, 1828 (Oligochaeta: Naididae) as a toxicity test organism Полный текст
2020
Castro, Gleyson B. | Pinheiro, Fernanda R. | Felipe, Mayara C. | Bernegossi, Aline C. | Girolli, Douglas | Gorni, Guilherme R. | Corbi, Juliano J.
Ecotoxicological bioassays have been widely applied to evaluate the toxicity of substances in standardized test organisms. Nevertheless, the main challenge for researchers is the use of native species to express the effects of pollutants on aquatic biota. Thirty years ago, Smith and collaborators evaluate the possible use of Pristina longiseta (as Pristina leidyi) in acute toxicity test, developing some experiments using cadmium and vanadium as toxicants. The present work aimed to update the use of P. longiseta, in acute bioassays, presenting the occurrence and general characteristics of the species; adaptation of cultivation to tropical conditions; sensitivity tests using potassium chloride (KCl) and copper sulfate (CuSO₄) as reference substances standardized by OECD, USEPA, and ABNT; and acute exposure to zinc chloride (ZnCl₂). The results showed a successful use of this species as tropical test organism, which presented easy laboratory rearing and responded to the classical ecotoxicological index. The present study can increase the utilization of P. longiseta in bioassays for tropical regions and improve the evaluation of environmental impacts using a native species in ecotoxicological studies.
Показать больше [+] Меньше [-]Uranium accumulation and its phytotoxicity symptoms in Pisum sativum L Полный текст
2020
Gupta, Dharmendra K. | Vuković, Ana | Semenishchev, Vladimir S. | Inouhe, Masahiro | Walther, Clemens
Environmental contamination by uranium (U) and other radionuclides is a serious problem worldwide, especially due to, e.g. mining activities. Ultimate accumulation of released U in aquatic systems and soils represent an escalating problem for all living organisms. In order to investigate U uptake and its toxic effects on Pisum sativum L., pea plantlets were hydroponically grown and treated with different concentrations of U. Five days after exposure to 25 and 50 μM U, P. sativum roots accumulated 2327.5 and 5559.16 mg kg⁻¹ of U, respectively, while in shoots concentrations were 11.16 and 12.16 mg kg⁻¹, respectively. Plants exposed to both U concentrations showed reduced biomass of shoots and reduced content of photosynthetic pigments (total chlorophyll and carotenoids) relative to control. As a biomarker of oxidative stress, lipid peroxidation (LPO) levels were determined, while antioxidative response was determined by catalase (CAT) and glutathione reductase (GR) activities as well as cysteine (Cys) and non-protein thiol (NP-SH) concentrations, both in roots and shoots. Both U treatments significantly increased LPO levels in roots and shoots, with the highest level recorded at 50 μM U, 50.38% in shoots and 59.9% in roots relative to control. U treatment reduced GR activity in shoots, while CAT activity was increased only in roots upon treatment with 25 μM U. In pea roots, cysteine content was significantly increased upon treatment with both U concentrations, for 19.8 and 25.5%, respectively, compared to control plants, while NP-SH content was not affected by the applied U. This study showed significant impact of U on biomass production and biochemical markers of phytotoxicity in P. sativum, indicating presence of oxidative stress and cellular redox imbalance in roots and shoots. Obtained tissue-specific response to U treatment showed higher sensitivity of shoots compared to roots. Much higher accumulation of U in pea roots compared to shoots implies potential role of this species in phytoremediation process.
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