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Resultados 1741-1750 de 6,473
Critical biomarkers for myocardial damage by fine particulate matter: Focused on PPARα-regulated energy metabolism
2020
Zhang, Ze | Su, Huilan | Ahmed, Rifat Zubair | Zheng, Yuxin | Jin, Xiaoting
Fine particulate matter is one of the leading threats to cardiovascular health worldwide. The exploration of novel and sensitive biomarkers to detect damaging effect of fine particulate matter on cardiac tissues is of great importance in the better understanding of haze-caused myocardial injury. A link between heart failure and PPARα-regulated energy metabolism has been confirmed previously. Herein, the study intends to reveal the critical biomarkers of fine particulate matter induced myocardial damage from the PPARα-regulated energy metabolism. Ambient fine particulate matter induced severe pathological alterations in cultured cells, accompanied by the decrease in ATP content. Additionally, the expressions of CPT1/CPT2 and levels of CS and MDH, crucial members in β-oxidation and the TCA cycle, were significantly decreased. In direct contrast, fine particulate matter increased the biomarkers of glycolysis, as measured by the accumulation of pyruvate and lactate contents, and the enhanced activities of HK and PKM1/2. Importantly, fine particulate matter-exposed cardiomyocytes exhibited the reduced PPARα level, that increased when cardiomyocytes were co-incubation with WY-14643 and fine particulate matter. Simultaneously, the adverse impact of fine particulate matter on critical biomarkers were observed in β-oxidation, TCA cycle and glycolysis, associated with WY-14643 additional complement. Fine particulate matter caused the myocardial energy metabolism transformation through the regulation of PPARα expression and translation, which provided novel and critical biomarkers for haze particles-caused myocardial damage.
Mostrar más [+] Menos [-]Sulfur-modified biochar as a soil amendment to stabilize mercury pollution: An accelerated simulation of long-term aging effects
2020
Zhao, Bin | O’Connor, David | Shen, Zhengtao | Tsang, Daniel C.W. | Rinklebe, Jörg | Hou, Deyi
The stability of mercury (Hg) contamination in soil environments can change over time. This has implications for agricultural sites under long-term management after in situ treatment involving soil amendments. In this study, rice husk biochar (RHB) and sulfur modified rice husk biochar (SRHB) were synthesized and applied (dosage = 5% dry wt.) to a Hg polluted agricultural soil collected from Guizhou province, Southern China (soil total Hg content = 28.3 mg/kg; C = 2%; and, S = 0.1%). The long-term stabilization effectiveness of the soil treatments was evaluated by a combined approach involving: (i) accelerated aging for 104 simulated years; (ii) soil extraction as a proxy for plant uptake; and, (iii) sequential extraction to identify Hg fractions. The SRHB amendment raised the soil’s total S content by approximately an order of magnitude (to 0.9%), which remained at a generally constant level throughout the simulation. The initial pH levels for the untreated and treated soils were alkaline and remained between 7.0 and 7.5 for the first 50 years of simulated aging, before decreasing as the simulation time increased further. The pH of the SRHB treated soils did not drop below that of untreated soils during the simulation. Soil extraction tests with 0.1 M HCl solution indicated that RHB and SRHB treatments could effectively immobilize the Hg in soil for at least 50 and 75 simulated years, respectively. At simulated year 50, the amount of Hg extracted from RHB and SRHB treated soils was <200 ng/L and <100 ng/L, respectively. Thus, showing SRHB to be a particularly promising remedial option. The soil Hg was mostly associated with the stable sequential extraction fractions (F3-5). By the end of the simulation, the F5 fraction for SRHB and RHB treated soils reduced by 44.6%, and 42.0%, respectively, whereas the F4 fraction increased by >400% in both cases. In summary, SRHB may provide long-lasting Hg stabilization at contaminated sites. Therefore, further research toward the development of this stabilization technology is warranted.
Mostrar más [+] Menos [-]Stranded cetaceans warn of high perfluoroalkyl substance pollution in the western Mediterranean Sea
2020
López-Berenguer, G. | Bossi, R. | Eulaers, I. | Dietz, R. | Peñalver, J. | Schulz, R. | Zubrod, J. | Sonne, C. | Martínez-López, E.
Perfluoroalkyl substances (PFASs) are a class of organohalogenated compounds of environmental concern due to similar characteristics as the well-studied legacy persistent organic pollutants (POPs) that typically show environmental persistence, biomagnification and toxicity. Nevertheless, PFAS are still poorly regulated internationally and in many aspects poorly understood. Here, we studied liver and muscle concentrations in five cetacean species stranded at the southeastern coast of Spain during 2009–2018. Twelve of the fifteen targeted compounds were detected in >50% of the liver samples. Hepatic concentrations were significantly higher than those in muscle reflecting the particular toxicokinetics of these compounds. Bottlenose dolphins Tursiops truncatus showed the highest hepatic ΣPFAS (n = 5; 796.8 ± 709.0 ng g⁻¹ ww) concentrations, followed by striped dolphin Stenella coeruleoalba (n = 29; 259.5 ± 136.2 ng g⁻¹ ww), sperm whale Physeter macrocephalus (n = 1; 252.8 ng g⁻¹ ww), short-beaked common dolphin Delphinus delphis (n = 2; 240.3 ± 218.6 ng g⁻¹ ww) and Risso’s dolphin Grampus griseus (n = 1; 78.7 ng g⁻¹ ww). These interspecies differences could be partially explained by habitat preferences, although they could generally not be related to trophic position or food chain proxied by stable N (δ¹⁵N) and C (δ¹³C) isotope values, respectively. PFAS profiles in all species showed a similar pattern of concentration prevalence in the order PFOS>PFOSA>PFNA≈PFFUnA>PFDA. The higher number of samples available for striped dolphin allowed for evaluating their PFAS burden and profile in relation to the stranding year, stable isotope values, and biological variables including sex and length. However, we could only find links between δ¹⁵N and PFAS burdens in muscle tissue, and between stranding year and PFAS profile composition. Despite reductions in the manufacturing industry, these compounds still appear in high concentrations compared to more than two decades ago in the Mediterranean Sea and PFOS remains the dominating compound.
Mostrar más [+] Menos [-]De novo RNA-Seq analysis in sensitive rice cultivar and comparative transcript profiling in contrasting genotypes reveal genetic biomarkers for fluoride-stress response
2020
Banerjee, Aditya | Singh, Ankur | Roychoudhury, Aryadeep
The fluoride-sensitive indica rice cultivar, IR-64 was subjected to NaF-treatment for 25 days, following which RNA-Seq analysis identified significant up and down regulation of 1,303 and 93 transcripts respectively. Gene ontology (GO) enrichment analysis classified transcripts into groups related to ‘cellular part’, ‘membrane’, ‘catalytic activity’, ‘transporter activity’, ‘binding’, ‘metabolic processes’ and ‘cellular processes’. Analysis of differentially expressed genes (DEGs) revealed fluoride-mediated suppression of abscisic acid (ABA) biosynthesis and signaling. Instead, the gibberellin-dependent pathway and signaling via ABA-independent transcription factors (TFs) was activated. Comparative profiling of selected DEGs in IR-64 and fluoride-tolerant variety, Khitish revealed significant cytoskeletal and nucleosomal remodelling, accompanied with escalated levels of autophagy in stressed IR-64 (unlike that in stressed Khitish). Genes associated with ion, solute and xenobiotic transport were strongly up regulated in stressed IR-64, indicating potential fluoride entry through these channels. On the contrary, genes associated with xenobiotic mobility were suppressed in the tolerant cultivar, which restricted bioaccumulation and translocation of fluoride. Pairwise expression profile analysis between stressed IR-64 and Khitish, supported by extensive statistical modelling predicted that fluoride susceptibility was associated with high expression of genes like amino acid transporter, ABC transporter2, CLCd, MFS monosaccharide transporter, SulfT2.1 and PotT2 while fluoride tolerance with high expression of Sweet11.
Mostrar más [+] Menos [-]Ticking bomb: Prolonged faecal shedding of novel coronavirus (2019-nCoV) and environmental implications
2020
Olusola-Makinde, Olubukola Olayemi | Reuben, Rine Christopher
The current global coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a tremendous public health challenge globally. While the respiratory transmission of SARS-CoV-2 has been established, evolving reports on the impact of the gastrointestinal system and the prolonged faecal shedding of SARS-CoV-2 show the likelihood of faecally mediated transmission. The increasing evidential presence of SARS-CoV-2 in wastewater and faecal material poses a significant public health threat which may potentiate global vulnerability to high risk of human exposure through environmental drivers especially in less developed countries. While extensively exploring the likelihood of faecally mediated SARS-CoV-2 transmission, infection control and prevention measures aimed at mitigating this pandemic should holistically include environmental drivers.
Mostrar más [+] Menos [-]Degradation of PAHs during long range transport based on simultaneous measurements at Tuoji Island, China, and at Fukue Island and Cape Hedo, Japan
2020
Shimada, Kojiro | Nohchi, Masayuki | Yang, Xiaoyang | Sugiyama, Taichi | Miura, Kaori | Takami, Akinori | Satō, Kei | Chen, Xuan | Kato, Shungo | Kajii, Yoshizumi | Meng, Fan | Hatakeyama, Shirō
We investigated the degradation of polycyclic aromatic hydrocarbons (PAHs) during long-range transport. Aerosols were collected simultaneously at remote sites on Tuoji Island, China; Fukue Island, Japan; and the Cape Hedo Atmosphere and Aerosol Measurement Station (CHAAMS), Okinawa, Japan in April, October, and December from 2012 to 2013. These remote sites were convenient for investigating the degradation of PAHs during long-range transport. PAHs were analyzed via gas chromatography/mass spectrometry. We identified air masses that passed over all sites and combined our measurements with a chemical transport model. We estimated the relative contributions of the PAHs at the three sites by normalizing the PAH concentrations to elemental carbon. Benzo[a]pyrene persisted in 5–16% of samples. The results of this study are consistent with laboratory studies in which secondary organic aerosol (SOA) coatings protected PAHs from degradation by ozone. We detected an inhibition of the degradation PAHs by SOA coatings by collecting PAHs simultaneously at the three sites. To elucidate the major sources of the SOAs, we carried out a positive matrix factorization analysis to identify the major sources of SOA coating, which controls the lifetime of PAHs. In spring and winter, the contribution of vehicle emissions was higher (46%) at Tuoji Island than at CHAAMS (13%). In contrast, the contribution of coal combustion was higher at CHAAMS (59%) than at Tuoji Island (28%). This result implies that during long-range transport, PAHs derived from coal combustion are more slowly degraded than PAHs derived from vehicle emissions. We found that the viscosity of SOA coatings derived from vehicle emissions in China was low, and the corresponding PAHs were rapidly degraded. In contrast, the viscosity of SOA coatings derived from coal combustion was high, and degradation of the corresponding PAHs was relatively slow. These results imply that PAHs derived from coal combustion have long lifetime.
Mostrar más [+] Menos [-]Evaluating national ecological risk of agricultural pesticides from 2004 to 2017 in China
2020
Jiao, Cong | Chen, Lei | Sun, Cheng | Jiang, Yue | Zhai, Limei | Liu, Hongbin | Shen, Zhenyao
In recent years, excessive application and loss of pesticides have caused great risks to the aquatic systems, but the spatio-temporal variability in the ecological risk that agricultural pesticides pose to aquatic systems has not been explored at the national scale. In this study, an integrated assessment framework was proposed for the potential ecological risk of surface water caused by agricultural pesticide loss. The spatio-temporal variability in the potential ecological risk caused by agricultural pesticide runoff was evaluated. Based on the results, the total pesticide emissions increased from 165.47 tons in 2004 to 179.77 tons in 2017. Among the three pesticide types, insecticide had the largest application, but its runoff was estimated as the lowest. High-risk areas of insecticide runoff were concentrated in the east, south and central part of China, while the central region of China was identified as a hotspot due to the high and the ever-increasing ecological risk. This study provides an integrated method for potential ecological risk assessment of agricultural pesticide runoff to adjacent water bodies in large-scale regions and the results of the study have direct implications for environmental policies on pesticide management in China and around the world.
Mostrar más [+] Menos [-]Exposure to diclofop-methyl induces cardiac developmental toxicity in zebrafish embryos
2020
Cao, Zigang | Huang, Yong | Xiao, Juhua | Cao, Hao | Peng, Yuyang | Chen, Zhiyong | Liu, Fasheng | Wang, Honglei | Liao, Xinjun | Lu, Huiqiang
Diclofop-methyl (DM) is one of the most widely used herbicides in agriculture production and has been frequently detected in both freshwater and environments, even agricultural products. However, the potential toxic effects of DM on organisms and the underlying mechanisms are still poorly understood. In this study, we utilized zebrafish to evaluate the toxicity of DM during the cardiovascular developmental process. Exposure of zebrafish embryos to 0.75, 1.0 and 1.25 mg/L DM induced cardiac defects, such as pericardial edema, slow heart rate and long SV-BA distance but the vascular development in zebrafish larvae was not influenced by DM treatment. The expression of cardiac-related genes were disordered and DM exposure initiated disordering cardiogenesis from the period of precardiac mesoderm formation. Moreover, the apoptosis and proliferation of cardiomyocytes were not influenced but the levels of oxidative stress were upregulated by DM exposure. Fullerenes and astaxanthin was able to rescue cardiac defects caused by DM via downregulating oxidative stress. Wnt signaling was downregulated after DM treatment and activation of Wnt signaling could rescue cardiac defects. Therefore, our results suggest that DM has the potential to induce cardiac developmental toxicity through upregulation of Wnt-Mediated (reactive oxygen species) ROS generation in zebrafish larvae.
Mostrar más [+] Menos [-]Modelling of methylene blue adsorption using peroxidase immobilized functionalized Buckypaper/polyvinyl alcohol membrane via ant colony optimization
2020
Jun, Lau Yien | Karri, Rama Rao | Mubarak, N.M. | Yon, Lau Sie | Bing, Chua Han | Khalid, Mohammad | Jagadish, Priyanka | Abdullah, E.C.
Jicama peroxidase (JP) was covalently immobilized onto functionalized multi-walled carbon nanotube (MWCNT) Buckypaper/Polyvinyl alcohol (BP/PVA) membrane and employed for degradation of methylene blue dye. The parameters of the isotherm and kinetic models are estimating using ant colony optimization (ACO), which do not meddle the non-linearity form of the respective models. The proposed inverse modelling through ACO optimization was implemented, and the parameters were evaluated to minimize the non-linear error functions. The adsorption of MB dye onto JP-immobilized BP/PVA membrane follows Freundlich isotherm model (R² = 0.99) and the pseudo 1st order or 2nd kinetic model (R² = 0.980 & 0.968 respectively). The model predictions from the parameters estimated by ACO resulted values close the experimental values, thus inferring that this approach captured the inherent characteristics of MB adsorption. Moreover, the thermodynamic studies indicated that the adsorption was favourable, spontaneous, and exothermic in nature. The comprehensive structural analyses have confirmed the successful binding of peroxidase onto BP/PVA membrane, as well as the effective MB dye removal using immobilized JP membrane. Compared to BP/PVA membrane, the reusability test revealed that JP-immobilized BP/PVA membrane has better dye removal performances as it can retain 64% of its dye removal efficiency even after eight consecutive cycles. Therefore, the experimental results along with modelling results demonstrated that JP-immobilized BP/PVA membrane is expected to bring notable impacts for the development of effective green and sustainable wastewater treatment technologies.
Mostrar más [+] Menos [-]A theorem on a product of lognormal variables and hybrid models for children’s exposure to soil contaminants
2020
Li, Zijian
This study developed hybrid Bayesian models to investigate the modeling process for children’s exposure to soil contaminants, which involves the intrinsic uncertainty of the exposure model, people’s judgments regarding random variables, and limited data resources. A hybrid Bayesian p-box was constructed, which was facilitated by a multiple integral dimensionality reduction (MIDR) theorem. The results indicated that exposure frequency (EF) dominated the exposure dose. The hybrid Bayesian p-box for the Frequentist-Bayesian (F–B) model at the 95th percentile of the simulated average daily dose (ADD) values corresponded to a 4.40 order-of-magnitude difference between the upper and lower bounds of the p-box. This considerable uncertainty was magnified by the combination of the highest posterior density (HPD) regions for three groups of the distribution parameters. For the Interior-Bayesian (I–B) hybrid model, the uncertainty of the outcomes, namely, [1.75 × 10⁻⁸, 2.18 × 10⁻⁸] mg kg⁻¹d⁻¹, was limited by the HPD regions for only one parameter unless the hyperparameters for the variables’ distributions were further evaluated. It was concluded that the hybrid models could provide a novel understanding of the complexity of the exposure modeling process compared to the traditional modeling method.
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