细化搜索
结果 3071-3080 的 5,151
Effects of soil pyrene contamination on growth and phenolics in Norway spruce (Picea abies) are modified by elevated temperature and CO2 全文
2018
Zhang, Yaodan | Virjamo, Virpi | Du, Wenchao | Yin, Ying | Nissinen, Katri | Nybakken, Line | Guo, Hongyan | Julkunen-Tiitto, Riitta
With the constant accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil and increasing temperature and CO₂ levels, plants will inevitably be exposed to combined stress. Studies on the effects of such combined stresses are needed to develop mitigation and adaptation measures. Here, we investigated the effects of soil pyrene contamination (50 mg kg⁻¹) on growth and phenolics of 1-year-old Norway spruce seedlings from five different origins in Finland at elevated temperature (+ 2 °C) and CO₂ (+ 360 ppm). Pyrene significantly decreased spruce height growth (0–48%), needle biomass (0–44%), stem biomass (0–43%), and total phenolic concentrations in needles (2–13%) and stems (1–19%) compared to control plants. Elevated temperature alone did not affect growth but led to lower concentrations of total phenolics in needles (5–29%) and stems (5–18%) in both soil treatments. By contrast, elevated CO₂ led to higher needle biomass (0–39%) in pyrene-spiked soils and higher concentrations of stem phenolics (0–18%) in pyrene-spiked and control soils compared to ambient treatments. The decrease in height growth and phenolic concentrations caused by pyrene was greater at elevated temperature, while elevated CO₂ only marginally modified the response. Seedlings from different origins showed different responses to the combined environmental stressors. The changes in growth and in the quantity and quality of phenolics in this study suggest that future climate changes will aggravate the negative influence of soil pyrene pollution on northern conifer forest ecosystems.
显示更多 [+] 显示较少 [-]Toxicity of nanotitanium dioxide (TiO2-NP) on human monocytes and their mitochondria 全文
2018
Ghanbary, Fatemeh | Seydi, Enaytollah | Naserzadeh, Parvaneh | Sālimī, Aḥmad
The effect of nanotitanium dioxide (TiO₂-NP) in human monocytes is still unknown. Therefore, an understanding of probable cytotoxicity of TiO₂-NP on human monocytes and underlining the mechanisms involved is of significant interest. The aim of this study was to assess the cytotoxicity of TiO₂-NP on human monocytes. Using biochemical and flow cytometry assessments, we demonstrated that addition of TiO₂-NP at 10 μg/ml concentration to monocytes induced cytotoxicity following 12 h. The TiO₂-NP-induced cytotoxicity on monocytes was associated with intracellular reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) collapse, lysosomal membrane injury, lipid peroxidation, and depletion of glutathione. According to our results, TiO₂-NP triggers oxidative stress and organelles damages in monocytes which are important cells in defense against foreign agents. Finally, our findings suggest that use of antioxidants and mitochondrial/lysosomal protective agents could be of benefit for the people in the exposure with TiO₂-NP.
显示更多 [+] 显示较少 [-]Thin films containing oxalate-capped iron oxide nanomaterials deposited on glass substrate for fast Fenton degradation of some micropollutants 全文
2018
Rambu, AliciaPetronela | Nadejde, Claudia | Schneider, RudolfJ. | Neamtu, Mariana
The main goal of the study was to evaluate the catalytic activity of two hybrid nanocatalysts consisting in Fe₃O₄ nanoparticles modified with either chitosan (CS) or polyethylene glycol (PEG)/ferrous oxalate (FO), and further deposited on solid substrate as thin films. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were employed for the structural and morphological characterizations of the heterogeneous catalysts. The degradation kinetic studies of two reactive azo dye (Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84)) as well as Bisphenol A (BPA) solutions were carried out using Fenton-like oxidation, in the presence of different concentrations of H₂O₂, at initial near-neutral pH and room temperature. The results indicated that a low amount of catalytic material (0.15 g/L), deposited as thin film, was able to efficiently trigger dye degradation in solution in the presence of 6.5 mmol/L H₂O₂ for RB5 and of only 1.6 mmol/L H₂O₂ in the case of BPA and RY84. In the presence of complex matrices such as WWTP waters, the removal of BPA was low (only 24% for effluent samples). Our findings recommend the studied immobilized nanocatalysts as promising economical tools for the pre-treatment of wastewaters using advanced oxidation processes (AOPs).
显示更多 [+] 显示较少 [-]NO3−/NH4+ proportions affect cadmium bioaccumulation and tolerance of tomato 全文
2018
Nogueirol, RobertaCorrêa | Monteiro, FranciscoAntonio | de Souza Junior, JoãoCardoso | Azevedo, RicardoAntunes
With the growth of the world population, cadmium (Cd) concentration in the environment has increased considerably as a result of human activities such as foundry, battery disposal, mining, application of fertilizers containing toxic elements as impurities, and disposal of metal-containing waste. Higher plants uptake N as ammonium (NH₄⁺), nitrate (NO₃ ⁻), and many other water-soluble compounds such as urea and amino acids, and nourishing plants with N, providing part of it as NH₄⁺, is an interesting alternative to the supply of this nutrient in the exclusive form of NO₃ ⁻ under Cd toxicity. The objective was to evaluate the influence of NO₃ ⁻ /NH₄⁺ proportions on the development and tolerance of tomato plants grown under the presence of Cd in the culture medium. The experiment was conducted in a completely randomized block design in a 3 × 3 factorial arrangement consisting of three Cd rates (0, 50, and 100 μmol L⁻¹) and three NO₃⁻/NH₄⁺ proportions (100/0, 70/30, and 50/50) in the nutrient solution. To this end, we quantified the responses of the antioxidant enzymatic system and productive and functional changes in Solanum lycopersicum var. esculentum (Calabash Rouge). Shoot biomass production decreased with the maximum Cd rate (100 μmol L⁻¹) tested in the growth medium, whereas the NO₃ ⁻ /NH₄⁺ proportions and other Cd rates did not significantly influence this variable. The lowest SPAD values were observed at the 100/0 NO₃ ⁻ /NH₄⁺ proportion and in plants exposed to Cd. The largest accumulation of the metal occurred in the shoots at the NO₃ ⁻ /NH₄⁺ proportion of 70/30 and at 100 μmol L⁻¹ Cd and in the roots at 100/0 NO₃⁻/NH₄⁺ and with 50 and 100 μmol L⁻¹ Cd. The concentration and accumulation of NO₃⁻ were highest at the NO₃⁻/NH₄⁺ proportion of 100/0 in the shoots and at 50/50 NO₃⁻/NH₄⁺ in the roots, whereas for NH₄⁺, values were higher as the proportion of N supplied in the form of NH₄⁺ was increased. The nitrate reductase enzyme activity decreased with the Cd supply in the nutrient solution. The antioxidant system enzymes were activated as we increased the NO₃⁻/NH₄⁺ proportion and/or Cd rates added to the nutrient solution in both shoots and roots of the tomato plant, except for ascorbate peroxidase. Based on the results obtained, if the plant is to be used as a food source as is the case of tomato, the 100/0 NO₃⁻/NH₄⁺ proportion is the better alternative because it resulted in higher Cd accumulation in the root system over the translocation to the shoots and consequently to the fruit.
显示更多 [+] 显示较少 [-]In vivo assessment of polydatin, a natural polyphenol compound, on arsenic-induced free radical overproduction, gene expression, and genotoxicity 全文
2018
Arslan-Acaroz, Damla | Zemheri, Fahriye | Demirel, HasanHuseyin | Kucukkurt, Ismail | Ince, Sinan | Eryavuz, Abdullah
Arsenic (As) is a well-known contaminant of global groundwater. Its exposure causes several hazardous effects on animals and human via oxidative stress. The present study examined the effect of polydatin (PD) on free radical overproduction in rats exposed to As. Thirty-five male rats randomly allocated into five equal groups. To the control group, physiological saline was given orally and to the second group only 100 mg/L As was given by drinking water for 60 days. The other groups were treated with As (100 mg/L) and PD orally at 50, 100, and 200 mg/kg/day, respectively. Treatment with As enhanced malondialdehyde level but decreased glutathione level in blood, liver, kidney, brain, lung, and heart of rats. Also, As decreased superoxide dismutase and catalase activities of erythrocyte, liver, kidney, brain, lung, and heart in rats. Furthermore, As treatment gave rise to increased DNA damage and gene expressions of interleukin 1 beta (IL-1β), nuclear factor kappa beta (NFκB), p53, and tumor necrosis factor-α (TNF-α) in the lung, brain, kidney, and liver. However, treatment of PD ameliorated As-exposed lipid peroxidation, antioxidant enzymes activities, DNA damage, gene expressions, and histopathological changes in tissues. In conclusion, PD has a dose-dependent protective effect on lipid peroxidation and antioxidant defense mechanism in rats against As exposure.
显示更多 [+] 显示较少 [-]Health risk assessment of arsenic and heavy metals (Cd, Cu, Co, Pb, and Sn) through consumption of caviar of Acipenser persicus from Southern Caspian Sea 全文
2018
Sobhanardakani, Soheil | Tayebi, Lima | Hosseini, SeyedVali
In the current study contents of As, Cd, Cu, Co, Pb, and Sn were determined in the caviar of Persian sturgeon collected from Southern Caspian Sea sampling site. After acid digestion of caviar specimens, the concentrations of elements determined using ICP-OES. The results showed that the mean concentrations (mg kg⁻¹) of elements in caviar samples were 0.01 for As, 0.05 for Cd, 1.42 for Cu, 0.01 for Co, 0.01 for Pb, and 0.28 for Sn and for all the elements are significantly lower than the adverse level for the human consumption. Also, health risk index (HRI) values were within the safe limits (HRI < 1). Therefore, there is no potential health risk to adults and children via consumption of caviar. Due to the discharge of hazardous chemicals into the marine ecosystems especially the Caspian Sea, residue analysis of pollutants in the sea foods is recommended.
显示更多 [+] 显示较少 [-]Prokaryotic community profiling of local algae wastewaters using advanced 16S rRNA gene sequencing 全文
2018
Limayem, Alya | Micciche, Andrew | Nayak, Bina | Mohapatra, Shyam
Algae biomass-fed wastewaters are a promising source of lipid and bioenergy manufacture, revealing substantial end-product investment returns. However, wastewaters would contain lytic pathogens carrying drug resistance detrimental to algae yield and environmental safety. This study was conducted to simultaneously decipher through high-throughput advanced Illumina 16S ribosomal RNA (rRNA) gene sequencing, the cultivable and uncultivable bacterial community profile found in a single sample that was directly recovered from the local wastewater systems. Samples were collected from two previously documented sources including anaerobically digested (AD) municipal wastewater and swine wastewater with algae namely Chlorella spp. in addition to control samples, swine wastewater, and municipal wastewater without algae. Results indicated the presence of a significant level of Bacteria in all samples with an average of approximately 95.49% followed by Archaea 2.34%, in local wastewaters designed for algae cultivation. Taxonomic genus identification indicated the presence of Calothrix, Pseudomonas, and Clostridium as the most prevalent strains in both local municipal and swine wastewater samples containing algae with an average of 17.37, 12.19, and 7.84%, respectively. Interestingly, swine wastewater without algae displayed the lowest level of Pseudomonas strains < 0.1%. The abundance of some Pseudomonas species in wastewaters containing algae indicates potential coexistence between these strains and algae microenvironment, suggesting further investigations. This finding was particularly relevant for the earlier documented adverse effects of some nosocomial Pseudomonas strains on algae growth and their multidrug resistance potential, requiring the development of targeted bioremediation with regard to the beneficial flora.
显示更多 [+] 显示较少 [-]PCB exposure and potential future cancer incidence in Slovak children: an assessment from molecular finger printing by Ingenuity Pathway Analysis (IPA®) derived from experimental and epidemiological investigations 全文
2018
Ghosh, Somiranjan | Loffredo, Christopher A. | Mitra, Partha S. | Trnovec, Tomas | Palkovicova Murinova, Lubica | Sovcikova, Eva | Hoffman, Eric P. | Makambi, Kepher H. | Dutta, S. K. (Sisir K.)
The risk of cancer due to PCB exposure in humans is highly debated. In eastern Slovakia, high exposure of the population to organochlorines (especially PCBs) was associated with various disease and disorder pathways, viz., endocrine disruption, metabolic disorder & diabetes, and cancer, thereby disturbing several cellular processes, including protein synthesis, stress response, and apoptosis. We have evaluated a Slovak cohort (45-month children, at lower and higher levels of PCB exposure from the environment) for disease and disorder development to develop early disease cancer biomarkers that could shed new light on possible mechanisms for the genesis of cancers under such chemical exposures, and identify potential avenues for prevention.Microarray studies of global gene expression were conducted from the 45-month-old children on the Affymetrix platform followed by Ingenuity Pathway Analysis (IPA®) to associate the affected genes with their mechanistic pathways. High-throughput qRT-PCR TaqMan low-density array (TLDA) was performed to further validate the selected genes on the whole blood cells of the most highly exposed children from the study cohort (n = 71). TP53, MYC, BCL2, and LRP12 differential gene expressions suggested strong relationships between potential future tumor promotion and PCB exposure in Slovak children. The IPA analysis further detected the most important signaling pathways, including molecular mechanism of cancers, prostate cancer signaling, ovarian cancer signaling, P53 signaling, oncostatin M signaling, and their respective functions (viz., prostate cancer, breast cancer, progression of tumor, growth of tumor, and non-Hodgkin’s disease). The results suggest that PCB exposures, even at the early age of these children, may have lifelong consequences for the future development of chronic diseases.
显示更多 [+] 显示较少 [-]Use of high-strength electromagnetic radiation to remove phototrophic biofilms from terracotta artifacts 全文
2018
Cennamo, Paola | Pasquino, Nicola | Guarino, Vincenza | Morra, Vincenzo | Giorgio, Antonella | Caputo, Paolo | Moretti, Aldo
A novel technique, effective in eliminating biodeteriogens from biofilms encrusting terracotta artifacts, is presented here. This method is based on the use of high-strength electromagnetic radiation (EMR) in the radiofrequency band. Shards of terracotta from historical pots at the Botanical Garden of Naples, Italy, were used. The shards, after sterilization, were inoculated with several phototrophic microorganisms previously isolated from whole terracotta pots. The newly formed biofilms were exposed to EMR amplitude modulated by a train of rectangular pulses with Tr = 200 ns repetition time and 10% duty cycle. The exposure protocol consisted of three applications of 2 h each, every other day. Denaturing gradient gel electrophoresis analyses conducted on the newly formed biofilms showed that, after the first exposure to EMR, all species in the biofilms but one were still alive. The second exposure resulted in the disappearance of 9 out of 13 species that were initially present on the samples. After the third exposure, all species disappeared. Superficial layers of terracotta from the exposed samples, transferred to a culture medium at 24 °C for 72 h, did not show any re-growing of organisms. Petrographic analyses of the sampleswere carried out before and after the treatments; they showed that exposure to EMR did not cause structural alterations in the treated substrates. Moreover, the amplitude of the EMR that samples were exposed to was not high enough to cause any significant increase in the temperature of the substrates; that is, no thermal effect, which is the most relevant effect when matter or organisms containing water are exposed to EMR, was observed. Finally, the field strength of the EMR showed to be non-invasive for the artifacts and non-dangerous for operators and the environment as compared to other techniques adopted in the field of conservation of cultural heritage.
显示更多 [+] 显示较少 [-]Effect of humic and fulvic acid transformation on cadmium availability to wheat cultivars in sewage sludge amended soil 全文
2018
Rashid, Imran | Murtaza, Ghulam | Zahir, ZahirAhmad | Fārūq, Muḥammad
The high nutrients and organic matter (OM) content of sewage sludge make it an excellent fertilizer to enhance soil fertility and crop production. However, the presence of adsorbed and precipitated forms of heavy metals, especially cadmium (Cd), can be a major problem for such a utilization of sludge. This pot study aims at producing safe food with minimal Cd concentrations from sewage sludge amended soils. Two wheat cultivars (NARC-11 and Shafaq-06) were sown in soil amended with sewage sludge with rates 0, 15 and 30 g kg⁻¹ soil. Application of sewage sludge resulted in enhancement of wheat grain yield while Cd concentrations in wheat grains of both cultivars remained within permissible limits (24.1 to 58.6 μg kg⁻¹ dry weight). Fourier transform infrared (FTIR) spectroscopic analysis revealed more spectral changes in fulvic acids than in humic acids, which showed a higher humification degree, making them chemically and biologically more stable for Cd retention. Sequential extraction data of Cd after NARC-11 harvest exhibited a significant decrease in mobile fractions (exchangeable and reducible fractions were reduced by 3.6 and 5.2%, respectively) and increase in immobile fraction (the oxidizable and residual fractions increased by 7 and 1.8%, respectively). It is concluded that sewage sludge application could be useful for the improvement of wheat production due to formation of stable humate complexes and decrease in Cd availability.
显示更多 [+] 显示较少 [-]