Search results for "COMET ASSAY"
showing 10 items of 52 documents
A comparative investigation of DNA adducts, DNA strand breaks and gene mutations induced by benzo[a]pyrene and (+/-)-anti-benzo[a]pyrene-7,8-diol 9,1…
1997
Abstract Genotoxic effects of benzo[ a ]pyrene (BP) and its reactive metabolites (±)- anti -benzo[ a ]pyrene-7,8-diol 9,10-oxide ((±)- anti -BPDE) were comparatively investigated in vitro with the permanent human fibroblast cell line MRC5CV1. Induced DNA adducts were measured by 32 P-postlabeling, DNA strand breakage was determined by the comet assay and the HPRT gene mutation test was used to detect cytotoxicity and mutagenicity. Treatment of MRC5CV1 cells with S9 mix-activated BP or with (±)- anti -BPDE resulted in a concentration-dependent increase in DNA adducts and strand breaks. Genotoxic effects of BP and (±)- anti- BPDE were detected by 32 P-postlabeling and the comet assay with sim…
Swimming pool water--fractionation and genotoxicological characterization of organic constituents.
2005
Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…
DNA double-strand breaks trigger apoptosis in p53-deficient fibroblasts
2001
DNA double-strand breaks (DSBs) are induced by ionizing radiation (IR) and various radiomimetic agents directly, or indirectly as a consequence of DNA repair, recombination and replication of damaged DNA. They are ultimately involved in the generation of chromosomal aberrations and were reported to cause genomic instability, gene amplification and reproductive cell death. To address the question of whether DSBs act as a trigger of apoptosis, we induced DSBs by means of restriction enzyme electroporation and compared the effect with IR in mouse fibroblasts that differ in p53 status [wild-type (+/+) versus p53-deficient (-/-) cells]. We show that (i) electroporation of PVU:II is highly effici…
Detection of DNA effects in human cells with the comet assay and their relevance for mutagenesis
1996
The single cell gel test (SCG-test or comet assay) is a rapid and sensitive method for measuring DNA damage and repair in individual cells. A wide variety of mutagens have been shown to cause DNA alterations detectable with the comet assay, but it is not yet clear whether a relationship exists between the DNA effects and the induction of mutations. We are therefore investigating in a cell culture system with human cells (MRC5CV1) the induction of DNA damage by environmental mutagens and the formation of mutations at the HPRT gene. In the present study we investigated benzo[a]pyrene (BP), an environmental mutagenic and carcinogenic polycyclic aromatic hydrocarbon, and its reactive metabolite…
Protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino-1-methyl-6-phenylimidazo…
2002
Abstract Chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1 (V79-rCYP1A2-rSULT1C1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (AAF) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Antigenotoxic activities of juices from spinach and red beets against AAF could be monitored with similar effectivity by the HPRT-mutagenicity test (IC50=0.64%; 2.57%) and alkaline single cell gel electrophoresis (comet assay; IC50=0.12%; 0.89%) which detects DNA stran…
Unexpected DNA damage caused by polycyclic aromatic hydrocarbons under standard laboratory conditions
2007
Abstract The genotoxicity of 15 polycyclic aromatic hydrocarbons was determined with the alkaline version of the comet assay employing V79 lung fibroblasts of the Chinese hamster as target cells. These cells lack the enzymes necessary to convert PAHs to DNA-binding metabolites. Surprisingly, 11 PAHs, i.e., benzo[ a ]pyrene (BaP), benz[ a ]anthracene, 7,12-dimethylbenz[ a ]anthracene, 3-methylcholanthrene, fluoranthene, anthanthrene, 11 H -benzo[ b ]fluorene, dibenz[ a,h ]anthracene, pyrene, benzo[ ghi ]perylene and benzo[ e ]pyrene caused DNA strand breaks even without external metabolic activation, while naphthalene, anthracene, phenanthrene and naphthacene were inactive. When the comet as…
Upon oxidative stress, the antiapoptotic Hsp60/procaspase-3 complex persists in mucoepidermoid carcinoma cells.
2008
Hsp60, a mitochondrial chaperonin highly conserved during evolution, has been found elevated in the cytosol of cancer cells, both in vivo and in vitro, but its role in determining apoptosis during oxidative stress (OS) has not yet been fully elucidated. The aim of the present work was to study the effects of OS on Hsp60 levels and its interactions with procaspase- 3 (p-C3) and p53 in tumor cells. NCI-H292 (mucoepidermoid carcinoma) cells were exposed to various concentrations of hydrogen peroxide (H2O2) for 24 hours. Cell viability was determined by Trypan blue and MTT assays. DNA damage was assessed by the Comet assay, and apoptosis was measured by the AnnexinV cytofluorimetric test. Expos…
The nucleotide excision repair protein XPC is essential for bulky DNA adducts to promote interleukin-6 expression via the activation of p38-SAPK
2016
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, and many are potent carcinogens. Benzo[a]pyrene (B[a]P), one of the best-studied PAHs, is metabolized ultimately to the genotoxin anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE). BPDE triggers stress responses linked to gene expression, cell death and survival. So far, the underlying mechanisms that initiate these signal transduction cascades are unknown. Here we show that BPDE-induced DNA damage is recognized by DNA damage sensor proteins to induce activation of the stress-activated protein kinase (SAPK) p38. Surprisingly, the classical DNA damage response, which involves the kinases ATM and ATR, is not involved in p38-SA…
Modifications of expression of genes and proteins involved in DNA repair and nitric oxide metabolism by carbatonides [disodium-2,6-dimethyl-1,4-dihyd…
2017
Abstract Studies on the pathogenesis of diabetes mellitus complications indicate that the compounds reducing free radicals and enhancing DNA repair could be prospective as possible remedies. Carbatonides, the disodium-2,6-dimethyl-1,4- dihydropyridine-3,5-bis(carbonyloxyacetate) derivatives, were tested for these properties. EPR spectroscopy showed that metcarbatone was an effective scavenger of hydroxyl radicals produced in the Fenton reaction, etcarbatone, and propcarbatone were less effective, styrylcarbatone was ineffective. UV/VIS spectroscopy revealed that styrylcarbatone manifested a hyperchromic effect when interacting with DNA, while all other carbatonides showeda hypochromic effec…
Toxicological profile of cereulide, the Bacillus cereus emetic toxin, in functional assays with human, animal and bacterial cells
2007
International audience; Some strains of the endospore-forming bacterium Bacillus cereus produce a heat-stable ionophoric peptide, cereulide, of high human toxicity. We assessed cell toxicity of cereulide by measuring the toxicities of crude extracts of cereulide producing and non-producing strains of B. cereus, and of pure cereulide, using cells of human, animal and bacterial origins. Hepatic cell lines and boar sperm, with cytotoxicity and sperm motility, respectively, as the end points, were inhibited by <= 1 nM of cereulide present as B. cereus extract. RNA synthesis and cell proliferation in HepG2 cells was inhibited by 2 nM of cereulide. These toxic effects were explainable by the acti…