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Результаты 5311-5320 из 6,560
Incidence of morphometry variation, growth alteration, and reproduction performance of the annular sea bream (Diplodus annularis) as effective tools to assess marine contamination: how useful is a multi-biotimarkers approach? Полный текст
2020
Gharred, Tahar | Mannai, Rabeb | Belgacem, Mariem | Jebali, Jamel
A wide variety of contaminants in the aquatic environment causes several deleterious effects on aquatic organism traits ranging from molecular to individual and population levels. This in situ study investigated morphometry, growth performance, and reproduction success of a teleost fish, Diplodus annularis, from a polluted site “Sayada” and a reference site “Salakta” in the eastern Tunisian coastline. Morphometric indexes, generalized Procruste analysis, thin plate, and otolith contour methods were used to assess the pollution effects on morphological traits. The growth performance of fish from contaminated and control sites were studied using the Von Bertalanffy equation. Gonadosomatic (GSI) and Hepatosomatic (HSI) Indexes and absolute and relative fecundity were used to assess the impact of pollution on the reproduction success of this species. The obtained results showed that the fish of the contaminated zone had significant alteration of the morphology, slower growth, significant increase in the HSI, significant decrease in female GSI, and a decrease in absolute and relative fecundity compared to specimens from the unpolluted zone. Based on these results, the biological traits of Diplodus annularis can be used as biological biomarkers in the monitoring and protection programs of the marine contamination in the Mediterranean Sea.
Показать больше [+] Меньше [-]Metals, arsenic, pesticides, and microcystins in tilapia (Oreochromis niloticus) from aquaculture parks in Brazil Полный текст
2020
Lopes, Taciana Onesorge Miranda | Passos, Larissa Souza | Vieira, Luiza Valli | Pinto, Ernani | Dorr, Fabiane | Scherer, Rodrigo | de Andrade Salustriano, Nathacha | Carneiro, Maria Tereza Weitzel Dias | Postay, Lais Frigini | Gomes, Levy Carvalho
The production of Nile tilapia (Oreochromis niloticus) in Brazil exhibits the highest growth rate in the world and represents approximately 45% of the total fish production. The objective of the present study was to assess the risk for human health due the consumption of tilapia farmed in net cages in eight aquaculture parks in Brazil. The concentrations of pesticides (40 compounds), metals (Mn, Ni, Zn, Cd, Pb, and Sn), arsenic, and cyanotoxins (microcystins) were evaluated in 16 fish from each park. Among analyzed pesticides, pyraclostrobin (0.18–0.32 mg/kg) and fenthion (0.0026–0.0037 mg/kg) exhibited values above the limit of quantification in the tilapia from Aracoiaba, Castanhão, and Ilha Solteira. The highest concentrations of As (0.44 μg/g) in fish tissues were found in Juara, Mn (0.21 μg/g) in Castanhão, and Zi (11.5 μg/g) were found in Três Marias. Furnas and Linhares exhibited the lowest metal concentrations. The estimated daily intake of muscle by the average Brazilian with 70 kg body weight is below the reference dose for all studied metals in all parks. Total free microcystins showed an accumulation pattern (muscle < gill < liver). The highest concentration in muscle was found in Castanhão (1043 μg/kg) samples. The results showed that fish exhibited metal, As, and pesticide tolerable daily intake (TDI) below the limit and pose low risk for human consumption. Otherwise, TDI for microcystins in fish of all studied parks was above the maximum level recommended by the World Health Organization, indicating that there exists a toxicity risk of fish consumption.
Показать больше [+] Меньше [-]Investigation of the vulnerability of a partly covered karst feature in Veszprém, Hungary Полный текст
2020
Trájer, Attila J. | Mlinárik, Lilla | Hammer, Tamás | Földényi, Rita | Somlai, János | Bede-Fazekas, Ákos
Karst aquifers represent the most important renewable sources of drinking water. Because anthropogenic influences threaten the integrity of karst aquifers, it is important to determine the soil erosion and karst denudation rates. In order to study the complex signs of degradation processes of the karst, a paleodoline (paleo-polje) was selected near to the county seat Veszprém, Hungary. It was found that gamma radiation measurements can be a useful tool to detect the level of soil erosion since the low gamma radiation indicates the surface proximity of the carbonate bedrock. The level of gamma radiation also predicts the potential agricultural usability of a site. Both the patterns of contamination and the erosion attack zone are strongly defined by the relief. The gullies and the deepest parts of the karstic landscape are the traps of organic materials and pollutants. The amounts of ⁴⁰K and its decay products originate from the covering sediment and negatively correlate with the soil depth. In the case of covered karsts, the measuring of the concentration of radionuclides and field gamma-ray dose measurement together can characterize the general horizontal and vertical trends of soil erosion, the potential land use, and the vegetation.
Показать больше [+] Меньше [-]Impact assessment of Bt maize expressing the Cry1Ab and Cry2Ab protein simultaneously on non-target arthropods Полный текст
2020
Yin, Yue | Xu, Yudi | Cao, Kaili | Qin, Zifang | Zhao, Xinxin | Dong, Xuehui | Shi, Wangpeng
Transgenic maize expressing the Cry1Ab and Cry2Ab protein simultaneously from Bacillus thuringiensis (Bt-maize) has been grown for farm-scale study to investigate its potential impact to non-target arthropod (NTA). The trials were conducted between Bt maize 2A-7 and its parental line (B73-329) in Beijing, China, over 3 years. Richness (C), Shannon index (H), Pielou index (J), Simpson index (D), and Bray-Curtis index were used to evaluate the population dynamics and biodiversity of the dominant arthropods from per 50 plants in crop field. The mainly abundant groups were Aphidoidea, Araneae, Coccinellidae, Anthocoridae, and Thripidae which represented about 90% of the total number of NTA. Although the abundance of NTA varied from year to year, there is no significant difference between Bt maize and non-Bt maize field. Fluctuations were found at individual sample dates, but the trend of these descriptors remained consistent. Further analysis showed the biodiversity indexes of the dominant arthropods C, H, J, D, and Bray-Curtis dissimilarity between Bt maize producing Cry1Ab and Cry2Ab toxin simultaneously and its parental line had no significant difference except for some sampling dates. These results suggested that Bt maize is compatible with the NTAs and provides further evidence of the ecological impact of genetically modified maize.
Показать больше [+] Меньше [-]Assessment of bioaccumulation of cu and Pb in experimentally exposed spiders, Lycosa terrestris and Pardosa birmanica, using different exposure routes Полный текст
2020
Aziz, Nida | Butt, Abida | Elsheikha, Hany
Major concerns exist regarding the environmental and human health risks caused by exposure to heavy metals. Spiders are often used as a model in ecotoxicological studies to assess soil pollution. Here, we measured the bioaccumulation of copper (Cu) and lead (Pb) in spiders, Lycosa terrestris and Pardosa birmanica, by inductively coupled plasma mass spectrometry (ICP-MS). We investigated whether Cu and Pb accumulation differs according to different spider species, single versus combined metal exposure, and routes of exposure. Spiders were exposed to 10 mM CuSO₄ and 10 mM PbCl₂ solutions separately or in combination (10 mM + 10 mM) through different exposure routes (spiked soil and food) for 6 weeks. The effect of metals on the survival and body mass of exposed and unexposed (control) spiders was determined. We found that in both spider species, accumulation of metals increased with exposure time. In single metal exposure, Cu accumulation from food was higher than soil exposure in both spider species, whereas the opposite was observed for Pb. The simultaneous uptake of Cu and Pb significantly decreased from food and soil, respectively. Soil exposure caused more accumulation of metals in L. terrestris than P. birmanica. Metal exposure via contaminated food caused higher mortality compared to soil exposure. Body mass of both spider species was significantly decreased and negatively correlated with metal’s concentration. Overall, our results show that bioaccumulation efficiency of Cu and Pb differs significantly in spiders exposed to metal’s mixture compared to single metal exposure and is dependent on the exposure route, the type of metal, and spider species. More understanding of the effects of exposure to metal mixture and exposure routes is essential for designing and supporting risk assessment and ecological monitoring programs.
Показать больше [+] Меньше [-]Formula and basic geochemical research to create new technology for vegetation restoration of mine slag heap (slope) Полный текст
2020
Zhao, Wenting | Zhou, Yapeng | Xu, Hao
Vegetation restoration of slag heap (slope) is of great significance in environmental protection, but it is difficult because of the lack of soil. This study proposes a new technology for vegetation restoration of mine slag pile based on a mixed substrate of mine slag and soil. The ecological mechanism of vegetation in mountainous areas with soil–rock mix substrate was investigated through pot and field experiments, in which physical and chemical analyses of various components as well as the calculation of dosage and other parameters were performed. Soil testing formula, plant selection, pot experiment, and ground planting experiment were selected as the key links. The results showed that, in addition to N, P, K, and organic matter, the content of fine particles was the main factor determining whether the soil–rock mixture could meet the growth and development requirements of plants. The content of fine particles significantly affects the water-supply capacity and water-holding capacity of the soil–rock mixture matrix. The higher the content of fine particles, the better the water-supply capacity and water-holding capacity. The mixture of artificial rocks and fine soil could be stirred evenly when 50–200% fine soil or fine soil + tailings were mixed into the mine waste residue, thus providing good vegetation restoration effects.
Показать больше [+] Меньше [-]Rhynchosia rufescens AgNPs enhance cytotoxicity by ROS-mediated apoptosis in MCF-7 cell lines Полный текст
2020
Khader, Syed Zameer Ahmed | Syed Zameer Ahmed, Sidhra | Ganesan, Gayathri Menon | Mahboob, Mohamed Rafi | Vetrivel, Manimaran | Sankarappan, Manavalan | Manickam, Paulpandi
The present study deals with the synthesis of silver nanoparticles (AgNPs) from Rhynchosia rufescens and to evaluate its cytotoxic effect mediated through induced apoptosis. The reduction and capping of phytoconstituents was confirmed using FTIR demonstrating O–H and C–H stretching at different peaks. The size and the shape of the particle were determined using scanning electron microscopy (SEM) illustrating 1 μm to 100 nm in size and the composition of compounds in the AgNPs were revealed using XRD and EDX. The results of the antioxidant assays revealed that the synthesized AgNPs had significant radical scavenging potential in dose-dependent inhibition with 22–64% for DPPH and 25–41% for ferric reducing antioxidant power assay at the concentrations of 20–100 μg/ml. Further, the synthesized AgNPs demonstrated potent cytotoxic activity against human breast cancer (MCF-7) cell line with an IC₅₀ value of 26 ± 1.0 μg/ml by the MTT assay. Cytotoxicity was confirmed using AO/EtBr and DAPI staining method where nuclear condensation and fragmentation of cancer cells was observed after treatment with nanoparticle. The results were further confirmed by flow cytometry analysis which revealed the occurrence of apoptosis during the S phase in cell cycle exposing the potential of the AgNPs against MCF-7 cancer cell. From the results, we conclude that the synthesized AgNPs from Rhynchosia rufescens exhibited multifunctional properties. Graphical abstract
Показать больше [+] Меньше [-]Bacterial-mediated synthesis of silver nanoparticles and their significant effect against pathogens Полный текст
2020
Saeed, Saira | Iqbal, Atia | Ashraf, Muhammad Aqeel
Silver nanoparticles are potent antimicrobials and could be used as a promising alternative of conventional antibiotics. The aim of this study was to isolate bacteria from soil that have ability to produce AgNPs by secondary metabolite activity and their elucidation against human pathogens. These strains Escherichia coli, Exiguobacterium aurantiacumm, and Brevundimonas diminuta with NCBI accession number MF754138, MF754139, and MF754140 respectively were grown for secondary metabolite production. The nanoparticles were confirmed and characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Three parameters, temperature, pH, and AgNO3 concentration, were used to optimize the production of silver nanoparticles. Antimicrobial potential of these nanoparticles was addressed on the Muller-Hinton Agar, and their zones of inhibitions were measured. TEM analysis revealed the size and shape of the silver nanoparticles. All types of AgNPs were spherical in shape; their size range is from 5 to 50 nm. The findings of optimization study showed the maximum production of silver nanoparticles at the pH 9, temperature 37 °C, and 1 mM AgNO3 concentration. All the strains exhibited the great potential as antimicrobial agents against MRSA and several other MDR bacteria with minimum 10 mm to maximum 28 mm zone of inhibition. It was concluded that the present study is an eco-friendly approach for the synthesis of AgNPs that will be beneficial to control the nosocomial infections triggered by MRSA and other human pathogens.
Показать больше [+] Меньше [-]Application of electron beam water radiolysis for sewage sludge treatment—a review Полный текст
2020
Siwek, Malgorzata | Edgecock, Thomas
A review of the applicability of electron beam water radiolysis for sewage sludge treatment is presented. Electron beam treatment has been proven to be a successful approach to the disinfection of both wastewater and sewage sludge. Nevertheless, before 2000, there were concerns about the perceived high capital costs of the accelerator and with public acceptance of the usage of radiation for water treatment purposes. Nowadays, with increased knowledge and technological development, it may be not only possible but also desirable to use electron beam technology for risk-free sewage sludge treatment, disposal and bio-friendly fertiliser production. Despite the developing interest in this method, there has been no attempt to perform a review of the pertinent literature relating to this technology. It appears that understanding of the mechanism and primary parameters of disinfection is key to optimising the process. This paper aims to reliably characterise the sewage sludge electron beam treatment process to elucidate its major issues and make recommendations for further development and research. Graphical abstract
Показать больше [+] Меньше [-]Date palm fruit extract ameliorated pancreatic apoptosis, endocrine dysfunction and regulatory inflammatory cytokines in Streptozotocin-induced diabetes in rats Полный текст
2020
Hafez, Mona H. | Elblehi, Samar S. | El-Sayed, Yasser S.
The current work studied the mechanism(s) and ability by which date palm (Phoenix dactylifera L.) fruit extract (DPE) inspired a glucose-lowering impact in rats suffering from diabetes. Forty-eight albino rats were divided into six various experimental treatments after induction of diabetes by intraperitoneal infusion of streptozotocin (45 mg/kg bwt) as follows: normal control, DPE, diabetic control, diabetic glibenclamide (GLI), diabetic DPE, and diabetic GLI plus DPE-treated groups. In animals euthanized after 8 weeks, blood and pancreatic tissue samples were assembled to assess different biochemical and histopathological changes. The expressions of insulin, B cell lymphoma-2 (Bcl-2), and cysteine aspartate-specific protease-3 (caspase-3) in islet β cells were also evaluated using immunohistochemical assessment. Diabetic rats exhibited hyperglycemia; increment of pancreatic malondialdehyde (lipid peroxidation biomarker), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β); and decrement of plasma insulin and pancreatic antioxidants: glutathione, superoxide dismutase, and catalase values. Also, the pancreatic islets exhibited histopathological and morphometric alternations associated with weak positive insulin and Bcl-2 immunoreactivity and strong positive caspase-3 immunoreactivity. DPE and/or GLI, an anti-diabetic drug, improved the pancreatic histoarchitecture and improved β cell function and structure, which increased insulin levels and improved the insulin, Bcl-2, and caspase-3 immunoreactivity in diabetic rats. Nevertheless, the combined DPE and GLI therapy revealed a significant recovery and restoration of β cells’ structure and function. The date palm fruit has anti-apoptotic, anti-inflammatory, and antioxidant activities and hypoglycemic effects, which in turn play a pivotal role in avoiding the progression of diabetes mellitus. Moreover, it could potentiate the glucose-lowering activity of anti-diabetic drugs.
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