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Bisphenol A induces a rapid activation of Erk1/2 through GPR30 in human breast cancer cells Texto completo
2011
Dong, S. | Terasaka, S. | Kiyama, R.
Bisphenol A (BPA) has been considered as an endocrine disruptor due to its ability to interact with estrogen receptors (ERs). While G protein-coupled receptor 30 (GPR30) is a novel estrogen receptor, its role in BPA-induced activation of Erk1/2 remains unknown. Human breast cancer cell lines, MCF-7, MDA-MB-231 and SKBR3, were used as experimental models to discriminate between ERs-dependent, putative ERs-independent and/or GPR30-associated effects. BPA induced a rapid activation of Erk1/2 in both ERα/β-positive and negative breast cancer cells, and this effect was not blocked with an ER antagonist, ICI 182,780. A small interfering RNA assay revealed that the expression of GPR30 was necessary for BPA-induced activation of Erk1/2 and transcriptional regulation of c-fos. In addition, BPA regulates the expression of c-fos likely through an AP1-mediated pathway. As a conclusion, GPR30 plays an important role in the BPA-induced activation of Erk1/2 in a manner distinguishable from that in ERα-mediated signaling.
Mostrar más [+] Menos [-]To duckweeds (Landoltia punctata), nanoparticulate copper oxide is more inhibitory than the soluble copper in the bulk solution Texto completo
2011
Shi, Jiyan | Abid, Aamir D. | Kennedy, Ian M. | Hristova, Krassimira R. | Silk, Wendy K.
CuO nanoparticles (CuO-NP) were synthesized in a hydrogen diffusion flame. Particle size and morphology were characterized using scanning mobility particle sizing, Brunauer–Emmett–Teller analysis, dynamic light scattering, and transmission electron microscopy. The solubility of CuO-NP varied with both pH and presence of other ions. CuO-NP and comparable doses of soluble Cu were applied to duckweeds, Landoltia punctata. Growth was inhibited 50% by either 0.6mgL⁻¹ soluble copper or by 1.0mgL⁻¹ CuO-NP that released only 0.16mgL⁻¹ soluble Cu into growth medium. A significant decrease of chlorophyll was observed in plants stressed by 1.0mgL⁻¹ CuO-NP, but not in the comparable 0.2mgL⁻¹ soluble Cu treatment. The Cu content of fronds exposed to CuO-NP is four times higher than in fronds exposed to an equivalent dose of soluble copper, and this is enough to explain the inhibitory effects on growth and chlorophyll content.
Mostrar más [+] Menos [-]How to select the best tree planting locations to enhance air pollution removal in the MillionTreesNYC initiative Texto completo
2011
Morani, Arianna | Nowak, David J. | Hirabayashi, Satoshi | Calfapietra, Carlo
Highest priority zones for tree planting within New York City were selected by using a planting priority index developed combining three main indicators: pollution concentration, population density and low canopy cover. This new tree population was projected through time to estimate potential air quality and carbon benefits. Those trees will likely remove more than 10 000 tons of air pollutants and a maximum of 1500 tons of carbon over the next 100 years given a 4% annual mortality rate. Cumulative carbon storage will be reduced through time as carbon loss through tree mortality outweighs carbon accumulation through tree growth. Model projections are strongly affected by mortality rate whose uncertainties limit estimations accuracy. Increasing mortality rate from 4 to 8% per year produce a significant decrease in the total pollution removal over a 100 year period from 11 000 tons to 3000 tons.
Mostrar más [+] Menos [-]Trophically available metal – A variable feast Texto completo
2011
Rainbow, P. S. | Luoma, Samuel N. | Wang, Wen-Xiong
Assimilation of trace metals by predators from prey is affected by the physicochemical form of the accumulated metal in the prey, leading to the concept of a Trophically Available Metal (TAM) component in the food item definable in terms of particular subcellular fractions of accumulated metal. As originally defined TAM consists of soluble metal forms and metal associated with cell organelles, the combination of separated fractions which best explained particular results involving a decapod crustacean predator feeding on bivalve mollusc tissues. Unfortunately TAM as originally defined has subsequently frequently been used in the literature as an absolute description of that component of accumulated metal that is trophically available in all prey to all consumers. It is now clear that what is trophically available varies between food items, consumers and metals. TAM as originally defined should be seen as a useful starting hypothesis, not as a statement of fact.
Mostrar más [+] Menos [-]Ecotoxicity of nanosized TiO₂. Review of in vivo data Texto completo
2011
Menard, Anja | Drobne, Damjana | Jemec, Anita
This report presents an exhaustive literature review of data on the effect of nanoparticulate TiO₂ on algae, higher plants, aquatic and terrestrial invertebrates and freshwater fish. The aim, to identify the biologically important characteristics of the nanoparticles that have most biological significance, was unsuccessful, no discernable correlation between primary particle size and toxic effect being apparent. Secondary particle size and particle surface area may be relevant to biological potential of nanoparticles, but insufficient confirmatory data exist. The nanotoxicity data from thirteen studies fail to reveal the characteristics actually responsible for their biological reactivity because reported nanotoxicity studies rarely carry information on the physicochemical characteristics of the nanoparticles tested. A number of practical measures are suggested which should support the generation of reliable QSAR models and so overcome this data inadequacy.
Mostrar más [+] Menos [-]A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air Texto completo
2011
Zhang, Yuzhong | Deng, Shuxing | Liu, Yanan | Shen, Guofeng | Li, Xiqing | Cao, Jun | Wang, Xilong | Reid, Brian | Tao, Shu
Air–soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAHLMW₄) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAHLMW₄ within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air–soil exchange of gaseous phase semi-volatile organic chemicals.
Mostrar más [+] Menos [-]Vertical emission profiles for Europe based on plume rise calculations Texto completo
2011
Bieser, J. | Aulinger, A. | Matthias, V. | Quante, M. | Denier van der Gon, H.A.C.
The vertical allocation of emissions has a major impact on results of Chemistry Transport Models. However, in Europe it is still common to use fixed vertical profiles based on rough estimates to determine the emission height of point sources. This publication introduces a set of new vertical profiles for the use in chemistry transport modeling that were created from hourly gridded emissions calculated by the SMOKE for Europe emission model. SMOKE uses plume rise calculations to determine effective emission heights. Out of more than 40 000 different vertical emission profiles 73 have been chosen by means of hierarchical cluster analysis. These profiles show large differences to those currently used in many emission models. Emissions from combustion processes are released in much lower altitudes while those from production processes are allocated to higher altitudes. The profiles have a high temporal and spatial variability which is not represented by currently used profiles.
Mostrar más [+] Menos [-]Comparison of land nitrogen budgets for European agriculture by various modeling approaches Texto completo
2011
de Vries, W. | Leip, A. | Reinds, G.J. | Kros, J. | Lesschen, J.P. | Bouwman, A.F.
A comparison of nitrogen (N) budgets for the year 2000 of agro-ecosystems is made for the EU 27 countries by four models with different complexity and data requirements, i.e. INTEGRATOR, IDEAg, MITERRA and IMAGE. The models estimate a comparable total N input in European agriculture, i.e. 23.3–25.7 Mton N yr⁻¹, but N uptake varies more, i.e. from 11.3 to 15.4 Mton N yr⁻¹ leading to total N surpluses varying from 10.4 to 13.2 Mton N yr⁻¹. The estimated overall variation at EU 27 is small for the emissions of ammonia (2.8–3.1 Mton N yr⁻¹) and nitrous oxide (0.33–0.43 Mton N yr⁻¹), but large for the sum of N leaching and runoff (2.7–6.3 Mton N yr⁻¹). Unlike the overall EU estimates, the difference in N output fluxes between models is large at regional scale. This is mainly determined by N inputs, differences being highest in areas with high livestock density.
Mostrar más [+] Menos [-]Accumulation of mercury and methylmercury by mushrooms and earthworms from forest soils Texto completo
2011
Rieder, Stephan R. | Brunner, Ivano | Horvat, Milena | Jacobs, Anna | Frey, Beat
Accumulation of mercury and methylmercury by mushrooms and earthworms from forest soils Texto completo
2011
Rieder, Stephan R. | Brunner, Ivano | Horvat, Milena | Jacobs, Anna | Frey, Beat
Accumulation of total and methyl-Hg by mushrooms and earthworms was studied in thirty-four natural forest soils strongly varying in soil physico-chemical characteristics. Tissue Hg concentrations of both receptors did hardly correlate with Hg concentrations in soil. Both total and methyl-Hg concentrations in tissues were species-specific and dependent on the ecological groups of receptor. Methyl-Hg was low accounting for less than 5 and 8% of total Hg in tissues of mushrooms and earthworms, respectively, but with four times higher concentrations in earthworms than mushrooms. Total Hg concentrations in mushrooms averaged 0.96 mg Hg kg⁻¹ dw whereas litter decomposing mushrooms showed highest total Hg and methyl-Hg concentrations. Earthworms contained similar Hg concentrations (1.04 mg Hg kg⁻¹ dw) whereas endogeic earthworms accumulated highest amounts of Hg and methyl-Hg.
Mostrar más [+] Menos [-]Accumulation of mercury and methylmercury by mushrooms and earthworms Texto completo
2011
Rieder, Stephan | Brunner, Ivano Livio | Horvat, Milena | Jacobs, Anna | Frey, Beat
Accumulation of total and methyl-Hg by mushrooms and earthworms was studied in thirty-four natural forest soils strongly varying in soil physico-chemical characteristics. Tissue Hg concentrations of both receptors did hardly correlate with Hg concentrations in soil. Both total and methyl-Hg concentrations in tissues were species-specific and dependent on the ecological groups of receptor. Methyl-Hg was low accounting for less than 5 and 8% of total Hg in tissues of mushrooms and earthworms, respectively, but with four times higher concentrations in earthworms than mushrooms. Total Hg concentrations in mushrooms averaged 0.96 mg Hg/kg dw whereas litter decomposing mushrooms showed highest total Hg and methyl-Hg concentrations. Earthworms contained similar Hg concentrations (1.04 mg Hg/kg dw) whereas endogeic earthworms accumulated highest amounts of Hg and methyl-Hg.
Mostrar más [+] Menos [-]Carbon isotope signature of dissolved inorganic carbon (DIC) in precipitation and atmospheric CO₂ Texto completo
2011
Górka, Maciej | Sauer, Peter E. | Lewicka-Szczebak, Dominika | Jędrysek, Mariusz Orion
This paper describes results of chemical and isotopic analysis of inorganic carbon species in the atmosphere and precipitation for the calendar year 2008 in Wrocław (SW Poland). Atmospheric air samples (collected weekly) and rainwater samples (collected after rain episodes) were analysed for CO₂ and dissolved inorganic carbon (DIC) concentrations and for δ¹³C composition. The values obtained varied in the ranges: atmospheric CO₂: 337–448ppm; δ¹³CCO₂ from −14.4 to −8.4‰; DIC in precipitation: 0.6–5.5mgdm⁻³; δ¹³CDIC from −22.2 to +0.2‰. No statistical correlation was observed between the concentration and δ¹³C value of atmospheric CO₂ and DIC in precipitation. These observations contradict the commonly held assumption that atmospheric CO₂ controls the DIC in precipitation. We infer that DIC is generated in ambient air temperatures, but from other sources than the measured atmospheric CO₂. The calculated isotopic composition of a hypothetical CO₂ source for DIC forming ranges from −31.4 to −11.0‰, showing significant seasonal variations accordingly to changing anthropogenic impact and atmospheric mixing processes.
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