[Show abstract][Hide abstract] ABSTRACT: The negative charge of LPS molecule and the presence of fatty acids in lipid A structure make it capable of binding with chitosan. In the presented work we analyzed the interactions of chitosan with LPS of Burkholderia cepacia or Proteus mirabilis and biological effects of these complexes on CHO-K1 cells. We observed that the presence of O-polysaccharide part of LPS (S1959), core region (R110) or lack of fatty acids in lipid A increased binding affinity of endotoxin with chitosan. However, lipid A of B. cepacia or P. mirabilis R45 might interact with CHO-K1 cells membrane alone or mediated by chitosan, respectively. In conclusion, the presence of two (B. cepacia) or one (P. mirabilis R45) Ara4N residues in lipid A part, promoted binding to cell membrane of CHO-K1 cells, alone or in the presence of chitosan, respectively. Chitosan reduced biological potencies of P. mirabilis lipid A R45 structure and this effect depended on the presence of O-PS. Lipid A of B. cepacia induced oxidative DNA damage in CHO-K1 cells.
[Show abstract][Hide abstract] ABSTRACT: Among nanomaterials, silver nanoparticles (AgNPs) have the broadest and most commercial applications due to their antibacterial properties, highlighting the need for exploring their potential toxicity and underlying mechanisms of action. Our main aim was to investigate whether AgNPs exert toxicity by inducing oxidative damage to DNA in human kidney HEK 293 cells. In addition, we tested whether this damage could be counteracted by plant extracts containing phytochemicals such as swertiamarin, mangiferin and homoorientin with high antioxidant abilities. We show that AgNPs (20nm) are taken up by cells and localised in vacuoles and cytoplasm. Exposure to 1, 25 or 100 µg/ml AgNPs leads to a significant dose-dependent increase in oxidised DNA base lesions (8-oxo-7,8-dihydroguanine or 8-oxoG) detected by the comet assay after incubation of nucleoids with 8-oxoG DNA glycosylase. Oxidised DNA base lesions and strand breaks caused by AgNPs were diminished by aqueous and methanolic extracts from both haulm and flower of Gentiana asclepiadea.
[Show abstract][Hide abstract] ABSTRACT: Abstract This study aims to assess the effects of Ag particles synthesised by a chemical (Ag 20, 200 nm) and biological method (Ag 23, 27 nm) in aquatic organisms: the bacterium Vibrio fischeri, the alga Desmodesmus subspicatus and the crustacean Daphnia magna. Ag particles exerted toxic effects in all organisms studied with Ag particles 23 nm being the most potent. Although soluble Ag was released in all media, the differences between the tested Ag particles still cannot be explained solely based on soluble Ag. NanoSIMS analysis performed with D. magna showed that apart from their localisation in the gut lumen, Ag 200 nm and Ag NPs 23 nm seemed to pass through the epithelial barrier as well. Ag NPs 23 nm localised in specific areas seemed to be within the ovaries. This study strengthens the argument that size, method of synthesis as well as surface chemistry may affect the uptake and toxic effects of Ag NPs.
[Show abstract][Hide abstract] ABSTRACT: Saponins are detergent-like substances showing antibacterial as well as anticancer potential. In this study, the effects of saponins from Quillaja saponaria were analyzed against prokaryotic and eukaryotic cells. Multidrug-resistant clinical E. coli strains were isolated from human urine. As eukaryotic cells, the CHO-K1 cell lines were applied. Antibacterial effect of ampicillin, streptomycin, and ciprofloxacin in the presence of saponins was measured by cultivation methods. Properties of saponins against CHO-K1 cells were measured by the MTT test, hemolysis assay and flow cytometry. Saponin from Quillaja saponaria has a cytotoxic effect at concentrations higher than 25 μg/mL and in the range of 12-50 μg/mL significantly increases the level of early apoptotic cells. Saponin at dose of 12 μg/mL enhances the six E. coli strains growth. We postulate that saponins increase the influx of nutrients from the medium into E. coli cells. Saponins do not have synergetic effects on antibacterial action of tested antibiotics. In contrary, in the presence of saponins and antibiotics, more CFU/mL E. coli cells were observed. This effect was similar to saponins action alone towards E. coli cells. In conclusion, saponins was cytotoxic against CHO-K1 cells, whereas against E. coli cells this effect was not observed.
BioMed Research International 02/2012; 2012(4):286216. DOI:10.1155/2012/286216 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The rapid expansion of nanotechnology promises to have significant benefits to society, yet there is increasing concern that exposure to nanoparticles (particles typically <100 nm in size) will have negative impact on both human and environmental health. Due to its well-known bactericide properties, silver nanoparticles (AgNPs) are nowadays among the most commercialized nanomaterials, but surprisingly
studies concerning toxicity at the cellular and molecular level are rather limited and the mechanisms that lay behind AgNPs toxicity are far from being understood. This critical review presents a detailed analysis of data on the in vitro and in vivo uptake, biodistribution, and toxicity of AgNPs. Emphasis is placed on
the systematization of data over animal and cell models, organs examined, doses applied, the type of particle administration, and the time of examination.
[Show abstract][Hide abstract] ABSTRACT: Neutropenia is the primary dose-limiting effect of etoposide toxicity resulting in a decreased efficiency of cancer treatment. Hence, the protection of neutrophils has important clinical implications. We investigated whether quercetin, due to its antioxidant properties, is able to modulate the damaging activity of etoposide. DNA damage, evaluated by the comet assay, and apoptosis, determined by FACScan flow cytometry using Annexin/PI, increased with etoposide doses. The intracellular level of reactive oxygen species (ROS) was enhanced in resting neutrophils incubated with etoposide at concentrations up to 25 microM; above this concentration etoposide revealed antioxidant properties. Only in latex-activated neutrophils, i.e. with latex-stimulated respiratory burst was the ROS production inhibited, as assessed by the luminol amplified chemiluminescence. The characteristic electron spin resonance (ESR) signal of etoposide phenoxyl radical, which occurs in the presence of myeloperoxidase, H2O2 and etoposide, was quenched by quercetin in a dose-dependent manner (0.1-0.5 microM). Quercetin also inhibited DNA damage induced by etoposide and enhanced the inhibitory action of etoposide on the ROS formation in neutrophils. However, quercetin (1 microM) lowered early and late apoptosis/necrosis only when apoptosis was induced by 25 microM etoposide; at higher etoposide concentration apoptosis was enhanced. Summing up, antioxidant adjuvant therapy using quercetin can be beneficial in prolonging neutrophils' lifespan in peripheral blood only when etoposide plasma concentration is low.
Toxicology in Vitro 10/2007; 21(6):1020-30. DOI:10.1016/j.tiv.2007.03.005 · 2.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The activity of cathepsins D and L, arginine aminopeptidase, dipeptidase II and dipeptidase IV was determined in the lysosomal, microsomal, cytoplasmatic fractions and in the complete homogenate of the mouse hepatocytes following injection of microcystin-YR and nodularin. The effect of both toxins depended on the time of action and on the fraction of cell cytoplasm. Microcystin-YR inhibited the synthesis of the studied proteases and caused a labialization of lysosomal membranes, whereas nodularin induced the synthesis of the enzymes and destabilized the reticulum endoplasmatic membranes.
[Show abstract][Hide abstract] ABSTRACT: Microcystine-YR (20 ug/kg bodyweight) and 8 ug/kg bodyweight of nodularin were intraperitoneally injected to 90 female Swiss mice. After 15, 30, 60 min and 24 h the changes were observed in the activity of some glucosidases in the complete cell homogenate and in the lysosomal, microsomal and cytosol fraction. Significant differences were connected with the time after administration of poison and with the cellular fraction. Nodularin induces the activity of beta-D-glucuronidase, alpha-glucosidase, lysosomal esterase and N-acetyl-glucosaminidase and influenced on the labilization of endoplasmatic reticulum membranes. Microcystine-YR inhibited the biosynthesis of glucosidases and revealed a destructive effect on membranes of lysosomes and endoplasmatic reticulum.