Bio-effects of static magnetic fields on cell growth and cell death have been investigated in suspension-cultured tobacco
cells as undifferentiated, embryonic plant cell model. The cells in their logarithmic growth phase were exposed to static
magnetic field with the magnitudes of 10 mT and 30 mT for 5 h/day. Exposure to static magnetic field ceased the growth and
caused an increase in cell death of exposed tobacco cells compared to those cells which were not treated with the field. Promotion
of cell death was accompanied by a harmonized increase in the activity of peroxidase and increase of lignifcation of cell
walls. 相似文献
Inhaled airborne particulate matter (PM) represents a potentially significant health hazard to humans. Exposure to PM strongly correlates with pulmonary inflammation and incidences of severe respiratory distress, including increased hospital admissions for breathing disorders, asthma, emphysema, and chronic bronchitis. PM generated from the combustion of fuel oils and coals contain a number of water-soluble transition metals including Fe, V, and Zn.
We have evaluated the impact of PM types with varying composition collected from the combustion of oils and coals on the health and metabolism of lung cell cultures. Three colorimetric assays (sulforhodamine B (SRB), Janus green, and MTT) have been adapted to quantify the impact of PM on rat lung alveolar type II epithelial cells (RLE-6TN cells). The PM toxicity metrics evaluated were inhibition of cell proliferation (SRB and Janus green) and inhibition of cellular metabolism (MTT). Cell proliferation is inhibited in a consistent dose-dependent manner by PM concentrations from 25 to 250 μg/ml. At a level of 100 μg/ml, oil-derived PM diminishes cell metabolism by as much as 40% relative to controls; the degree of inhibition is strongly dependent on PM particle size and metal content. Conversely, coal-derived PM at the same dosage diminishes cell metabolism by no more than 20% relative to controls. All three assays provide highly repeatable results and consistent toxicity rankings of the PMs evaluated. Overall, metabolic inhibition as measured by the MTT assay was deemed the most appropriate metric for PM toxicity, primarily due to its applicability with in vivo-like confluent cell monolayers. 相似文献
Cell wall polysaccharides play a vital role in binding with toxic metals such as copper(Cu)ions.However, it is still unclear whether the major binding site of Cu in the cell wall varies with different degrees of Cu stresses.Moreover, the contribution of each cell wall polysaccharide fraction to Cu sequestration with different degrees of Cu stresses also remains to be verified.The distribution of Cu in cell wall polysaccharide fractions of castor(Ricinus communis L.) root was investigated with various Cu concentrations in the hydroponic experiment.The results showed that the hemicellulose1(HC1) fraction fixed 44.9%–67.8% of the total cell wall Cu under Cu stress.In addition, the pectin fraction and hemicelluloses2(HC2) fraction also contributed to the Cu binding in root cell wall,accounting for 11.0%–25.9% and 14.1%–26.6% of the total cell wall Cu under Cu treatments, respectively.When the Cu levels were ≤ 25 μmol/L, pectin and HC2 contributed equally to Cu storage in root cell wall.However, when the Cu level was higher than 25 μmol/L, the ability of the pectin to bind Cu was easy to reach saturation.Much more Cu ions were bound on HC1 and HC2 fractions, and the HC2 played a much more important role in Cu binding than pectin.Combining fourier transform infrared(FT-IR) and twodimensional correlation analysis(2 D-COS) techniques, the hemicellulose components were showed not only to accumulate most of Cu in cell wall, but also respond fastest to Cu stress. 相似文献
UV filters are increasingly used in sunscreens and other personal care products. Although their residues have been widely identified in aquatic environment, little is known about the influences of UV filters to protozoan. The growth inhibition effects, cell viability and oxidative stress responses of four commonly used UV filters, 2-ethylhexyl 4-methoxycinnamate (EHMC), benzophenone-3 (BP-3), 4-methyl-benzylidene camphor (4-MBC) and octocrylene (OC), to protozoan Tetrahymena thermophila were investigated in this study. The 24-h EC50 values with 95% confidence intervals for BP-3 and 4-MBC were 7.544 (6.561–8.675) mg L−1 and 5.125 (4.874–5.388) mg L−1, respectively. EHMC and OC did not inhibit the growth of T. thermophila after 24 h exposure at the tested concentrations. The results of cell viability assays with propidium iodide (PI) staining were consistent with that of the growth inhibition tests. As for BP-3 and 4-MBC, the relatively higher concentrations, i.e. of 10.0 and 15.0 mg L−1, could lead to the cell membranes impairment after 4 h exposure. With the increase of the exposure time to 6 h, their adverse effects on cell viability of T. thermophila were observed at the relatively lower concentration groups (1.0 mg L−1 and 5.0 mg L−1). In addition, it is noticeable that at environmentally relevant concentration (1.0 μg L−1), BP-3 and 4-MBC could lead to the significant increase of catalase (CAT) activities of the T. thermophila cells. Especially for the BP-3, the oxidative injuries were further confirmed by the reduction of glutathione (GSH) content. It is imperative to further investigate the additive action of UV filters and seek other sensitive endpoint, especially at environmentally relevant concentration. 相似文献