خيارات البحث
النتائج 821 - 830 من 4,895
Railroad derived nitrogen and heavy metal pollution does not affect nitrogen fixation associated with mosses and lichens at a tundra site in Northern Sweden
2019
Goth, Astrid | Michelsen, Anders | Rousk, Kathrin
Traffic derived nitrogen (N) and heavy metal pollution is a well-known phenomenon, but little explored in otherwise pristine ecosystems such as subarctic tundra. Here, the main source of N input to the ecosystem is via N₂ fixation by moss- and lichen-associated bacteria. While inhibitory effects of N deposition on moss-associated N₂ fixation have been reported, we still lack understanding of the effects of traffic derived N and heavy metal deposition on this ecosystem function in an otherwise pristine setting. To test this, we established a distance gradient (0–1280 m) away from a metal pollution source -a railway transporting iron ore that passes through a subarctic birch forest. We assessed the effects of railway-derived pollution on N₂ fixation associated with two moss species Pleurozium schreberi, Hylocomium splendens and with the lichen Peltigera aphthosa. Deposition and availability of N and heavy metals (Fe, Cu, Zn, Pb) as well as the respective contents in moss, lichen and soil was assessed. While we found a steep gradient in metal concentration in moss, lichen and soil with distance away from the pollution source, N deposition did not change, and with that, we could not detect a distance gradient in moss- or lichen-associated N₂ fixation. Hence, our results indicate that N₂ fixing bacteria are either not inhibited by heavy metal deposition, or that they are protected within the moss carpet and lichen tissue.
اظهر المزيد [+] اقل [-]Environmental exposure to non-essential trace elements in two bat species from urbanised (Tadarida teniotis) and open land (Miniopterus schreibersii) areas in Italy
2019
Andreani, Giulia | Cannavacciuolo, Annunziata | Menotta, Simonetta | Spallucci, Valentina | Fedrizzi, Giorgio | Carpenè, Emilio | Isani, Gloria
Bats are particularly suited as bioindicators of trace element pollution due to their longevity and their position in the trophic chain. In this study, the concentrations of ten non-essential trace elements (Al, As, Ba, Cd, Hg, Pb, Sb, Sr, Th, Tl) were determined in the tissues (whole body, skin-fur, skinned body, liver, kidney and bone) of lactant Tadarida teniotis from a nursery colony in Rome. A large number of bats from this nursery died before fledging and had bone deformities and fractures. The concentrations of non-essential trace elements in bone and whole body were also analysed in adult specimens of Miniopterus schreibersii from a colony located in a natural park in Northern Italy. In lactant T. teniotis, the Pb concentration decreased in the following order: bone>liver>skinned body>whole body>skin-fur>kidney, and exceeded the toxic threshold associated with negative effects reported for different mammalian species. The levels of the other non-essential trace elements were within a range indicative of low environmental contamination in both species. Significant interspecies differences (P < 0.05) were observed for concentrations of Pb and Ba, higher in the bones of T. teniotis, and of Cd, Hg and Sr, higher in the bones of M. schreibersii. In lactant T. teniotis, the different sources of Pb exposure, through inhalation and/or food, may represent a potential threat to the colony of this synanthropic European bat.
اظهر المزيد [+] اقل [-]Exposure of low-dose fipronil enantioselectively induced anxiety-like behavior associated with DNA methylation changes in embryonic and larval zebrafish
2019
Qian, Yi | Ji, Chenyang | Yue, Siqing | Zhao, Meirong
Fipronil, a broad-spectrum chiral insecticide, has been documented to induce significant neurotoxicity to nontarget aquatic species; however, whether its neurotoxicity behaves enantioselectively and what molecular mechanisms correspond to the neurotoxicity remain unanswered. To date, few investigations have focused on the genomic mechanisms responsible for the enantioselective toxicity of chiral pesticides. The epigenetic modifications, especially DNA methylation, caused by the pesticides are also blind spot of the research works. Video tracking showed that R-fipronil exhibited more intense neurotoxicity, as well as the induction of more severe anxiety-like behavior, such as boosted swimming speed and dysregulated photoperiodic locomotion, to embryonic and larval zebrafish compared with S-fipronil. The MeDIP-Seq analysis, combined with Gene Ontology and KEGG, revealed that R-fipronil disrupted five signaling pathways (MAPK, Calcium signaling, Neuroactive ligand-receptor interaction, Purine metabolism, and Endocytosis) to a greater extent than S-fipronil through the hypermethylation of several important neuro-related genes, whereas no significant alterations of global DNA methylation were observed on the two enantiomers. To summarize, our data indicated that the fipronil-conducted enantioselective neurotoxicity likely applied its enantioselectivity by the dysregulation of DNA methylation. Our study also provided novel epigenetic insights into the study of enantioselective biological effects and the relevant underlying mechanisms of chiral insecticide.
اظهر المزيد [+] اقل [-]Understanding long-term variations of meteorological influences on ground ozone concentrations in Beijing During 2006–2016
2019
Chen, Ziyue | Zhuang, Yan | Xie, Xiaoming | Chen, Danlu | Cheng, Nianliang | Yang, Lin | Li, Ruiyuan
Recently, ground ozone has become one major airborne pollutant and the frequency of ozone-induced pollution episodes has increased rapidly across China. However, due to the lack of long-term observation data, relevant research on the characteristics and influencing factors of urban ozone concentrations remains limited. Based on ground ozone observation data during 2006–2016, we quantified the causality influence of individual meteorological factors on ozone concentrations in Beijing using a convergent cross mapping (CCM) method. The result indicated that the influence of each meteorological factor on ozone concentrations varied significantly across seasons and years. At the inter-annual scale, all-year meteorological influences on ozone concentrations were much more stable than seasonal meteorological influences. At the seasonal scale, meteorological influences on ozone concentrations were stronger in spring and autumn. Amongst multiple individual factors, temperature was the key meteorological influencing factor for ozone concentrations in all seasons except winter, when wind, humidity and SSD exerted major influences on ozone concentrations. In addition to temperature, air pressure was another meteorological factor that exerted strong influences on ozone concentrations. At both the inter-annual and seasonal scale, the influence of temperature and humidity on ozone concentrations was generally stable whilst that of other factors experienced large variations. Different from PM2.5, meteorological influences on ozone concentrations were relatively weak in summer, when ozone concentrations were the highest in Beijing. Given the generally stable meteorological influences on ozone concentrations and human-induced emissions of VOCs and NOx across seasons, warming induced notable increase in summertime biogenic emissions of VOCs and NOx can be a major driver for the increasing ozone pollution episodes. This research provides useful references for understanding long-term meteorological influences on ozone concentrations in mega cities in China.
اظهر المزيد [+] اقل [-]Biogeochemical characteristics and ecological risk assessment of pharmaceutically active compounds (PhACs) in the surface seawaters of Jiaozhou Bay, North China
2019
Peng, Quancai | Song, Jinming | Li, Xuegang | Yuan, Huamao | Li, Ning | Duan, Liqin | Zhang, Qian | Liang, Xianmeng
The occurrence and distribution of 168 pharmaceutically active compounds (PhACs) in the surface seawater of Jiaozhou Bay (JZB) were investigated using ultra-high-performance liquid chromatography in tandem with a triple-quadrupole mass spectrometer equipped with an electrospray ionization source (UHPLC-ESI-MS-MS). Thirty-six compounds were detected, and 17 of these compounds were first detected in seawater, including sulfabenzamide, sulphacetamide, cephalonium, desacetyl-cefotaxime, cefminox, cefotaxime, cephradine, cefazolin, carprofen, nabumetone, glibenclamide, glimepiride, glipizide, prednisone, fluoromethalone, diazepam and amantadine. The total concentration of PhACs in the surface seawater ranged from 23.6 ng/L to 217 ng/L. The compounds found at the highest mean concentrations included amantadine (24.7 ng/L), lincomycin (8.55 ng/L), carprofen (8.30 ng/L), and tetracycline (7.48 ng/L). The PhAC concentration was higher in the inner bay than in the outside of the bay. In the inner bay, the eastern district showed higher concentrations of PhACs than the western district. Input from the Licun River may be the primary source of pollution. A statistically significant positive correlation was observed between nutrients and PhACs in seawater. Phosphate can be used to indicate the distribution of PhACs in JZB. Based on the individual risk quotient (RQ) values, lincomycin and ofloxacin posed high risks to the relevant aquatic organisms in JZB, especially in the eastern parts. Regular monitoring is required to evaluate the levels of PhACs as they are constantly released into JZB.
اظهر المزيد [+] اقل [-]Sustainable remediation through the risk management perspective and stakeholder involvement: A systematic and bibliometric view of the literature
2019
Braun, Adeli Beatriz | Trentin, Adan William da Silva | Visentin, Caroline | Thomé, Antônio
Sustainable remediation is a new way of thinking and acting in the management of contaminated sites. This research aims to identify and structure the state-of-the-art of sustainable remediation from the risk management and stakeholder involvement perspective. A systematic and bibliometric study of scientific production was performed on scientific papers indexed in the Scopus and Web of Science databases with the objectives: 1) to select a bibliographic portfolio that is aligned with the perception of the researchers in regard to theme, 2) to perform a bibliometric analysis of the selected bibliographic portfolio, and 3) to conduct a thematic synthesis and identify the integration of sustainable remediation from the risk management and stakeholder involvement perspective. The results indicated that although sustainable remediation is a recent theme it presents a promising field for development worldwide, verified by the growing number of publications in recent years. A change is observed in the way risk management is considered with the rise of sustainable remediation, demonstrated by different approaches in publications. Likewise, the involvement of stakeholders is widely discussed, and the importance of their participation in decision-making processes in the field of sustainable remediation is identified. This research brings several and new contributions as it provides with a detailed overview and guidance about the main characteristics and peculiarities as well as what already exists, the form to approach, the advances and what still needs to be improved so that the perception of stakeholders and risk management are better understood within the context of sustainable remediation.
اظهر المزيد [+] اقل [-]Bisphenol S induced epigenetic and transcriptional changes in human breast cancer cell line MCF-7
2019
Huang, Wei | Zhao, Chao | Zhong, Huan | Zhang, Shoudong | Xia, Yiji | Cai, Zongwei
In recent years, concerns about using Bisphenol A (BPA) in daily consume products and its effects in many chronic human diseases have prompted the removal of BPA. However, the widely used BPA alternatives, including Bisphenol S (BPS), have a high structural similarity with BPA, suggesting that they may have similar biological effects towards human beings. Indeed, BPS was also found to have endocrine-disrupting effects. Epigenetic mechanism was reported to be involved in BPA-induced biological effects in both in vitro and in vivo models. However, there is no assessment on whether BPS could cause epigenetic changes. In this work, we investigated the possible epigenetic effects of BPS that might induce in human breast cancer cell line MCF-7. We found that BPS could change DNA methylation level of transposons. Besides, methylation status in promoter of breast cancer related genes CDH1, SFN, TNFRSF10C were also changed, which implied that BPS might play a role in the development of breast cancer. Gene expression profiling showed that some genes related to breast cancer progression were upregulated, including THBS4, PPARGC1A, CREB5, COL5A3. Gene ontology (GO) analysis of the differentially expressed genes revealed the significantly changes in PI3K-Akt signaling pathway and extracellular matrix, which were related to the proliferation, migration and invasion of breast cancer cells. These results illustrated that BPS exposure might play roles in the progression of breast cancer.
اظهر المزيد [+] اقل [-]Cardiogenesis impairment promoted by bisphenol A exposure is successfully counteracted by epigallocatechin gallate
2019
Lombó, Marta | González-Rojo, Silvia | Fernández-Díez, Cristina | Herráez, María Paz
Exposure to the emerging contaminant bisphenol A (BPA) is ubiquitous and associated with cardiovascular disorders. BPA effect as endocrine disruptor is widely known but other mechanisms underlying heart disease, such as epigenetic modifications, remain still unclear. A compound of green tea, epigallocatechin gallate (EGCG), may act both as anti-estrogen and as inhibitor of some epigenetic enzymes. The aims of this study were to analyze the molecular processes related to BPA impairment of heart development and to prove the potential ability of EGCG to neutralize the toxic effects caused by BPA on cardiac health. Zebrafish embryos were exposed to 2000 and 4000 μg/L BPA and treated with 50 and 100 μM EGCG. Heart malformations were assessed at histological level and by confocal imaging. Expression of genes involved in cardiac development, estrogen receptors and epigenetic enzymes was analyzed by qPCR whereas epigenetic modifications were evaluated by whole mount immunostaining. BPA embryonic exposure led to changes in cardiac phenotype, induced an overexpression of hand2, a crucial factor for cardiomyocyte differentiation, increased the expression of estrogen receptor (esr2b), promoted an overexpression of a histone acetyltransferase (kat6a) and also caused an increase in histone acetylation, both mechanisms being able to act in sinergy. EGCG treatment neutralized all the molecular alterations caused by BPA, allowing the embryos to go on with a proper heart development. Both molecular mechanisms of BPA action (estrogenic and epigenetic) likely lying behind cardiogenesis impairment were successfully counteracted by EGCG treatment.
اظهر المزيد [+] اقل [-]Glutathione biosynthesis plays an important role in microcystin-LR depuration in lettuce and spinach
2019
Cao, Qing | Liu, Weijing | Jiang, Weili | Shu, Xiubo | Xie, Liqiang
Irrigation of crop plants with microcystins (MCs) contaminated water could be a threat to human health via bioaccumulation. Despite the fact MCs bioaccumulation in crop plants is well documented, MCs depuration, as well as the mechanism involved remains unclear. The objectives of the present study were to investigate the bioaccumulation and depuration of microcystin-LR (MC-LR) in lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.), as well as to explore the role of glutathione (GSH) biosynthesis in MC-LR depuration. The tested plants were irrigated with deionized water containing 10 μg L⁻¹ MC-LR for 12 days (bioaccumulation), and subsequently, with either deionized water only or deionized water containing 0.5 mM buthionine sulfoximine (BSO, a specific inhibitor of GSH biosynthesis) for 12 days (depuration). After bioaccumulation period, highest concentrations of MC-LR found in lettuce and spinach were 114.4 and 138.5 μg kg⁻¹ dry weight (DW) respectively. Depuration rates of MC-LR in lettuce and spinach were 9.5 and 8.1 μg kg⁻¹ DW d⁻¹, which deceased to 3.7 and 4.6 μg kg⁻¹ DW d⁻¹ in treatments with BSO application. GSH content in both lettuce and spinach were not significantly affected during depuration without BSO; whereas after treatment with BSO, GSH content significantly decreased by 36.0% and 24.7% in lettuce and spinach on 15 d, and the decrease remained on 18 d and 21 d in lettuce. Moreover, during the bioaccumulation period, activities of glutathione reductase (GR) and glutathione S-transferase (GST) were enhanced in both plants. Our results suggested that GSH biosynthesis played an important role in MC-LR depuration in the tested plants. Concerning human health risk, most of the estimated daily intake (EDI) values during the bioaccumulation period exceeded the tolerable daily intake (TDI) guideline. However, the risk could be alleviated by irrigating with MCs-free water for a certain amount of time before harvest.
اظهر المزيد [+] اقل [-]Evaluation of mitochondrial toxicity of cadmium in clam Ruditapes philippinarum using iTRAQ-based proteomics
2019
Ji, Chenglong | Lu, Zhen | Xu, Lanlan | Li, Fei | Cong, Ming | Shan, Xiujuan | Wu, Huifeng
Cadmium is one of the most serious metal pollutants in the Bohai Sea. Previous studies revealed that mitochondrion might be the target organelle of Cd toxicity. However, there is a lack of a global view on the mitochondrial responses in marine animals to Cd. In this work, the mitochondrial responses were characterized in clams Ruditapes philippinarum treated with two concentrations (5 and 50 μg/L) of Cd for 5 weeks using tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining, ultrastructural observation and quantitative proteomic analysis. Basically, a significant decrease of mitochondrial membrane potential (△Ψm) was observed in clams treated with the high concentration (50 μg/L) of Cd. Cd treatments also induced specific morphological changes indicated by elongated mitochondria. Furthermore, iTRAQ-based mitochondrial proteomics showed that a total of 97 proteins were significantly altered in response to Cd treatment. These proteins were closely associated with multiple biological processes in mitochondria, including tricarboxylic acid (TCA) cycle, oxidative phosphorylation, fatty acid β-oxidation, stress resistance and apoptosis, and mitochondrial fission. These findings confirmed that mitochondrion was one of the key targets of Cd toxicity. Moreover, dynamical regulations, such as reconstruction of energy homeostasis, induction of stress resistance and apoptosis, and morphological alterations, in mitochondria might play essential roles in Cd tolerance. Overall, this work provided a deep insight into the mitochondrial toxicity of Cd in clams based on a global mitochondrial proteomic analysis.
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