Papers by Keyword: Uptake

Abstract: Nowadays, gold nanoparticles (AuNPs) received a great deal of attention for biomedical applications especially in diagnostic imaging and therapeutics. In this study, we elucidate on how size of gold nanoparticles (AuNPs) affect cellular uptake. The size dependence of AuNPs cytotoxicity in MCF-7 cells was tested by using the WST-1 assay. The sizes of AuNPs tested were 13 nm, 50 nm, and 70 nm. The toxicity of AuNPs in MCF-7 cell lines was quantified by determining the IC₅₀ values in WST-1 assays. The IC₅₀ values (inhibitory concentrations that affected 50% growth inhibition) of 13 nm AuNPs is higher than 50 nm and 70 nm AuNPs. Mean that, 13 nm AuNPs is less toxic to MCF-7 cells. This cytotoxicity results generally agree with those obtained in the study of cellular uptake by Inverted Microscope and EFTEM. Morphological observation of MCF-7 after being treated with 13 nm, 50 nm, and 70 nm AuNPs, were looking unhealthy and dying out of the populace, the observed cells were more reduced and dying as treatment with 50 nm and 70 nm AuNPs. Cells detachment, clumping, shrunken, and dispersed cells in the culture medium and floating cells were also observed. The observed morphological changes increase in 50 nm and 70 nm AuNPs than in 13 nm AuNPs, which is less toxic to MCF-7 cells. The presented morphological analysis has also established that 13 nm AuNPs showed less toxic to MCF-7 cells. The presented results clearly indicate that the cytotoxicity and cellular uptake of AuNPs depend on the size of the nanoparticles.

Abstract: The negative impact of soil salinity on agricultural yields is disturbing and significant, especially when related to agricultural plants, whose sensitivity to salinity is frequently, but not exclusively, associated with the abundance of Na⁺ in the soil, which in excess becomes toxic for plants. This work aims to propose an alternative for the control of Na⁺ present in waters from saline soils, by the possibility of applying bovine hydroxyapatite as a way to remedy this problematic. Hydroxyapatite powders were processed from bovine bone. The powders were characterized by X-ray diffraction analyses. Preliminary experiments were performed in batches at room temperature, adding together 5g hydroxyapatite and a dilute solution of sodium chloride. Liquid samples were analyzed by atomic absorption spectrophotometry. The results showed that the hydroxyapatite could be a promising alternative for the reduction of Na⁺ concentration in waters from saline soils.

Abstract: Several tonnes of useful chemicals are produced every year for use in households, agriculture production and industries. However, these chemicals move from their original production or application sites through the air, surface or groundwater or soils and are deposited in unintended places. The resultant contamination of these matrices and the subsequent effects on living organisms, have become a major concern for researchers and policy makers. This study aimed at using literature to briefly review the role of plants in identifying trichloroethene contamination in groundwater. It was found that plants, through direct contact with the soil and such processes as advective uptake, translocation, diffusion and particle deposition are able to incorporate most of these contaminants into their tissues and store them in leaves, branches and trunks. The entire process of removing TCE by this method has thus been found to be inexpensive, easy to undertake and has been shown to be environmentally friendly. It may therefore be an effective way for the identification and analysis of this contaminant.

Abstract: The effects of fly ash on heavy metal uptake by rice and Cd, Pb, Cu and Zn availibility in contaminated acidic soil were investigated in this study. The fly ash was added at 0, 20 and 40 g·kg^-1 dry weight soil, respectively. The results indicated that the addition of 20 g·kg^-1 fly ash significantly improved dry weights of leaves, stems and roots of rice. While at the rate of 40 g·kg^-1 fly ash, the dry weithts of leaves and stems of rice decreased. It was also showed that the application of fly ash substantially increased soil pH values from 4.0 to 5.1 and 6.4, and the higher increment was improved by the higher dosage. Further more, the addition of fly ash substantially decreased the avalibility of heavy metals, and the higher amendment dosage resulted in the lower NH₄NO₃ extractable heavy metal concentrations. These results demonstrated that the application of fly ash at 20 g·kg^-1 might be an effective strategy to decrease rice metal uptake and remediate heavy metal contaminated acidic soil.

Abstract: It is known that heavy metals are taken up and translocated by plants to different degrees. Phytoremediation, the use of plants to decontaminate soil by taking up heavy metals, shows considerable promise as a low-cost technique and has received much attention in recent years. However, its application is still very limited due to low biomass of hyperaccumulators, unavailability of the suitable plant species and long growing seasons required. Therefore, to maximize phytoextraction efficiency, it is important to select a fast-growing and high-biomass plant with high uptake of heavy metals, which is also compatible with mechanized cultivation techniques and local weather conditions. Trees in particular have a number of attributes (e.g. high biomass, economic value), which make them attractive plants for such a use. This paper reviews the potential for the phytoremediation of heavy metal-contaminated land by trees. In summary, we present the research progress of phytoremediation by trees and suggest ways in which this concept can be applied and improved.

Abstract: In this work, Ammonium Molybdophosphate (AMP) was synthesized and the adsorption of Cs onto it under different initial pH conditions was investigated. The results show the negative effect of the hydronium and hydroxyl irons on the uptake of Cs while the iron-exchange capacity can reach 144.8 mg/g. In addition, the structure differences between AMP samples before and after Cs adsorption were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman technique. The results show that the Keggin structure of AMP stayed unchanged while new bonds arose after the Cs adsorption.

Abstract: Tea saponin (TS), a representative tea seed-derived biosurfactant, was effective in promoting the uptake of Cd from soil by corn (Zea Mays L.). The concentration of Cd in roots increased with the growth of corn, while for shoots, concentration of Cd increased rapidly at the beginning and reached the maximum in a short period and then gradually decreased against the uptake time. Over a 5 day growth period, Cd concentration was 116.9 mg/kg in roots and 104.19 mg/kg in shoots which were both about 1.6 times as that without TS. In addition, the accumulated Cd in corn was greatly influenced by TS concentrations in shoots and roots, the Cd contents in corn shoots and roots increased with the increasing concentrations of TS added in soil. The higher Cd accumulation in the roots and shoots indicated that TS had the potential in enhancing the uptake of Cd into corn in the concentration ranged 25-200 mg/kg.

Abstract: The inability to sufficiently prevent and/or repair chemically-etched dental enamel serves as one example that underlines the importance and need for the development of innovative biomaterials for therapeutic applications. In this work we explored the seeding capability of 225 ppm and 1100 ppm fluoride with and without a novel β-tricalcium phosphate-silica-urea (TCP-Si-Ur) biomaterial (concentrations of 20, 40, 80, and 200 ppm) to mineralize into acid-etched bovine enamel. The nature of the mineralization was evaluated by measuring the fluoride and phosphate uptake into the eroded enamel, as well as the orthophosphate microstructure using infrared (IR) spectroscopy. These enamel fluoride uptake and IR experiments revealed a fluoride dose response exists for eroded enamel treated with 225 and 1100 ppm F. The inclusion of 20, 40, and 80 ppm TCP-Si-Ur with 225 ppm F was similar to 225 ppm F alone and did not produce a fluoride uptake dose response; however, 200 ppm TCP-Si-Ur combined with 1100 ppm F improved raw fluoride uptake relative to 1100 ppm F. Furthermore, we found the combination of either 225 ppm or 1100 ppm fluoride plus TCP-Si-Ur at different loading levels leads to unique and significant mineral integration into the PO4 enamel network, including the formation of P-F bonds. The observations reported herein demonstrate the combination of fluoride plus a novel TCP-Si-Ur biomaterial produces synergistic mineralization and bears significantly on eroded enamel microstructure.

Abstract: The present study is focused on the investigation of hexavalent chromium uptake by the yeast S. cerevisiae UCM Y–1968 and its protoplasts. For the first time the ability of S. cerevisiae protoplasts to accumulate Cr (VI) ions was shown. Under the influence of various concentrations of Cr (VI) ions, the proportion of the surviving yeast cells and protoplasts decreased as treatment time extended. During 0.5 – 1h of treatment, yeast protoplasts demonstrated a significant level of Cr (IV) ion accumulation, 44 – 47 % of the supplied Cr ions, whereas the initial strain S. cerevisiae UCM Y-1968 accumulated 9 – 10 %. The isotherms for S. cerevisiae UCM Y-1968 were related to L2 types and for yeast protoplasts isotherms were related to L3 types. Cr (VI) sorption/uptake parameters (Qmax, b) for living cells were found for S. cerevisiae UCM Y–1968 (Qmax = 890 μmol/g) and its protoplasts (Qmax = 1335 μmol/g) at the initial Cr (VI) ions concentration of 25 mg/l. The results showed that hexavalent chromium uptake by living yeasts biomass mainly depended on intracellular accumulation. Chromium uptake by protoplasts cells was characterized by simultaneous metabolism-dependent bioaccumulation with prevalence of the intracellular accumulation of Cr (VI) ions.

Abstract: To compare Cr (VI) tolerance, biosorption and bioaccumulation for initial carotenoidsproducing yeast Rhodotorula mucilaginosa UCM Y-1776 and its mutants, twenty stable mutants with various intensity of colors were obtained using nitrosoguanidine (NSG). The ultraviolet was found to be inefficient as a mutagen in our study. Light- and non-pigmented mutants (4L and 2) demonstrated a significant growth inhibition by 30 mg/l Cr (VI) whereas wild strain was able to grow at much higher chromium concentrations (500 mg/l). Cr (VI) sorption ability of R. mucilaginosa UCM Y-1776 was higher than those of mutants. Cr (VI) sorption/uptake parameters (Qmax, b) were found to be close for initial pink-pigmented R. mucilaginosa UCM Y-1776 (Qmax = 950 5M/g), and its light-pigmented mutant 4L (Qmax = 678 5M/g) and non-pigmented mutant 2 (Qmax = 790 5M/g) by non-living biomass. Non-pigmented “white” mutant 2 showed the highest ability to sorb chromium ions by living biomass (Qmax = 1020 mmol/g). The least chromiumtolerant light-pigmented (mutant 4L) and non-pigmented yeasts showed the highest chromium uptake for living biomass. The results showed that the presence of carotenoids did not affect Cr (VI) ions sorption by yeast biomass which could highlight significance of chitin and glucan-mannoprotein complex in chromium biosorption. However pigment absence increased Cr (VI) bioaccumulation by living yeast demonstrating the protective role of carotenoids against hexavalent chromium toxicity.