DNA damage repair is an essential cellular mechanism that maintains genome stability. Here, we show that the nonmethylable cytidine analog zebularine induces a DNA damage response in Arabidopsis thaliana, independent of changes in DNA methylation. In contrast to genotoxic agents that induce damage in a cell cycle stage-independent manner, zebularine induces damage specifically during strand syn...

background: this study has used biomarker of exposure-effect continuum to examine the biological characteristics of organophosphate (op) toxicity and its genotoxic effect among rice farmers.   materials and methods : a cross-sectional study was conducted among 160 pesticide exposed rice farmers and 160 adults from the fishing village as the unexposed group. they share the common socio-economica...

We have measured the level of DNA damage induced by treating roots (cellular Comet assay) and isolated root nuclei (acellular Comet assay) of catalase-deficient (CAT1AS) and wild-type (SR1) tobacco with the promutagen o-phenylenediamine (o-PDA) and the direct acting genotoxic agents hydrogen peroxide and ethyl methanesulphonate (EMS). The roots of CAT1AS have about 60% less catalase activity co...

Human toxic responses are very often related to metabolism. Liver metabolism is traditionally studied, but other organs also convert chemicals and drugs to reactive metabolites leading to toxicity. When DNA damage is found, the effects are termed genotoxic. Here we describe a comprehensive new approach to evaluate chemical genotoxicity pathways from metabolites formed in-situ by a broad spectru...

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using ...

Nuclear factor kappa B (NF-κB)-mediated transcription is an important mediator for cellular responses to DNA damage. Genotoxic agents trigger a 'nuclear-to-cytoplasmic' NF-κB activation signaling pathway; however, the early nuclear signaling cascade linking DNA damage and NF-κB activation is poorly understood. Here we report that Src-associated-substrate-during-mitosis-of-68kDa/KH domain contai...

Understanding how to recover fully functional and transcriptionally active chromatin when its integrity has been challenged by genotoxic stress is a critical issue. Here, by investigating how chromatin dynamics regulate transcriptional activity in response to DNA damage in human cells, we identify a pathway involving the histone chaperone histone regulator A (HIRA) to promote transcription rest...

Ascorbic acid is well known antioxidant. The antioxidant property can be helpful in reducing clastogenic, mutagenic and carcinogenic properties of certain chemical agents. In this context, an anticlastogenic activity of ascorbic was studied against the genotoxic damage induced by norethynodrel, using chromosomal aberrations and sister chromatid exchanges as parameters. The treatments of differe...

OBJECTIVE Irinotecan is a botanical derivative and an anti-cancer drug with cytotoxic and genotoxic effects. The present study evaluated the effect of Lactobacillus plantarum A7 on the genotoxic activity of irinotecan in a hepatocellular carcinoma cell line (HepG2) by comet assay. MATERIALS AND METHODS HepG2 were incubated with irinotecan (100 µM), heat-killed cells (0.025 µg/ml) + irinotecan...

OBJECTIVES To study whether sewage workers are exposed to genotoxic substances. An increased risk of cancers among sewage workers has been noted. If this increased risk is due to an exposure to genotoxic agents, primarily DNA damage could be used as a biological marker of exposure. METHODS In a cross sectional study, DNA damage in peripheral lymphocytes from 35 sewage workers and 30 controls ...