ABSTRACT
Archaeon Aeropyrum pernix K1 is an obligate aerobic hyperthermophilic organism with C25,25-archeol membrane lipids with head groups containing inositol. Interactions of archaeosomes, liposomes prepared from lipids of A. pernix, with mammalian cells in vitro were studied. In vitro cytotoxicity was tested on five different cell lines: rodent mouse melanoma cells (B16-F1) and Chinese hamster ovary (CHO) cells, and three human cell lines-epithelial colorectal adenocarcinoma cells (CACO-2), liver hepatocellular carcinoma cell line (Hep G2) and endothelial umbilical vein cell line (EA.hy926). Archaeosomes were nontoxic to human Hep G2, CACO-2 and mildly toxic to rodent CHO and B16-F1 cells but showed strong cytotoxic effect on EA.hy926 cells. Confocal microscopy revealed that archaeosomes are taken up by endocytosis. The uptake of archaeosomes and the release of loaded calcein are more prominent in EA.hy926 cells, which is in line with high toxicity toward these cells. The mechanisms of uptake, release and action in these cells as well as in vivo functioning have to be further studied for possible targeted drug delivery.
Subject(s)
Aeropyrum/chemistry , Drug Carriers/toxicity , Endocytosis/drug effects , Lipids/chemistry , Aeropyrum/growth & development , Animals , Biomass , CHO Cells , Cell Culture Techniques , Cell Line, Tumor , Cell Survival/drug effects , Cricetinae , Cricetulus , Dose-Response Relationship, Drug , Drug Carriers/isolation & purification , Drug Carriers/metabolism , Endothelial Cells , Humans , Lipids/isolation & purification , Liposomes , Mice , Microscopy, Confocal , Microscopy, FluorescenceABSTRACT
We provide experimental evidence that changes in the membrane fatty acid profile of Tetrahymena thermophila incubated with nano- or bulk TiO(2) particle are not accompanied by ROS generation or lipid peroxidation. Consequently these changes are interpreted as acclimation to unfavorable conditions and not as toxic effects. T. thermophila cells were exposed to TiO(2) particles at different concentrations for 24h at 32°C. Treatment of cultures with nano- and bulk TiO(2) particles resulted in changes of membrane fatty acid profile, indicating increased membrane rigidity, but no lipid peroxidation or ROS generation was detected. There were no differences in membrane composition when T. thermophila was exposed to nanosized or bulk-TiO(2) particles. We also observed reversible filling of food vacuoles, but this was different in case of nano- or bulk TiO(2) exposure. Our results suggest that interactions of particles and cell membranes are independent of oxidative stress.
Subject(s)
Fatty Acids/metabolism , Membrane Lipids/metabolism , Metal Nanoparticles , Tetrahymena thermophila/metabolism , Titanium/metabolism , Adaptation, Physiological , Chromatography, Gas , Tetrahymena thermophila/growth & development , Tetrahymena thermophila/physiologyABSTRACT
Extensive production and wide application of TiO(2) nanoparticles has stimulated research on its potential biological effects on different groups of organisms but the interaction of TiO(2) nanoparticles with higher plants remains poorly understood. We have studied the effect of TiO(2) nanoparticles on Allium cepa using a modification of the conventional Allium test with nanoparticles suspended in distilled water as opposed to growth medium. Nanoparticulate TiO(2) was found to have low toxic potential and the mitotic index was among the most sensitive measures of the effect of nano-TiO(2). We conclude that modified Allium test is suitable to provide comparative data on the biological potential of a variety of nanoparticles and could be used in a tiered approach to nanotoxicity testing.
Subject(s)
Metal Nanoparticles/toxicity , Onions/drug effects , Titanium/toxicity , Water Pollutants, Chemical/toxicity , Mitotic Index , Onions/growth & development , Onions/metabolism , Toxicity TestsABSTRACT
The aim of our work was to assess the pollution-induced community tolerance (PICT) of isopod gut microbiota and pollution-induced isopod population tolerance (PIPT). Animals collected from a chronically Hg polluted and an unpolluted location were exposed for 14 days to 10microg Hg/g dry food under laboratory conditions. The lysosomal membrane stability, hepatopancreas epithelium thickness, feeding activity and animal bacterial gut microbiota composition were determined. The results confirm the hypothesis that the response to short-term Hg exposure differs for animals from the Hg polluted and the unpolluted field locations. The animals and their gut microbiota from the Hg polluted location were less affected by Hg in a short-term feeding experiment than those from the unpolluted environment. We discuss the pollution-induced population tolerance of isopods and their gut microbiota as a measure of effects of long-term environmental pollution. The ecological consequences of such phenomena are also discussed.
Subject(s)
Environmental Pollutants/toxicity , Isopoda/drug effects , Mercury/toxicity , Animals , Drug Tolerance , Environmental Monitoring/methods , Feeding Behavior/drug effects , Intestines/microbiology , Isopoda/microbiology , Isopoda/physiology , Slovenia , Time Factors , Toxicity Tests, AcuteABSTRACT
The purpose of this study was to examine the results of treatment with a modified Herbst appliance. The pretreatment and posttreatment cephalometric and dental cast records of 32 consecutively treated Class II, Division 1 cases were evaluated. Results showed that the skeletal Class II correction was achieved by an average 1.5 mm of greater than normal forward mandibular growth in conjunction with a minimal "headgear" effect inhibiting maxillary growth. Dental Class II correction was achieved by significant amounts of distal bodily movement and tipping of the maxillary first molars combined with bodily forward movement of the mandibular first molars. Significant increases were seen in maxillary arch length and maxillary intercanine and intermolar widths, while the mandibular arch demonstrated few changes. Slight forward movement of the mandibular incisors was noted with no significant change occurring in the maxillary incisors.
