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...

this study aimed to investigate effects of malathion on dna breakage in the liver and gill of rainbow trout (oncorhynchus mykiss) in the laboratory condition. the experiment was performed with four concentrations of malathion, i.e. 0 (control), 0.025, 0.05 and 0.075 mg l‑1 and three replicate for nine days. the liver and gill were sampled on the first, fifth and ninth days after the start of th...

BACKGROUND Previous research reveals an association between traumatic stress and an increased risk for numerous diseases, including cancer. At the molecular level, stress may increase carcinogenesis via increased DNA damage and impaired DNA repair mechanisms. We assessed DNA breakage in peripheral blood mononuclear cells from individuals with post-traumatic stress disorder (PTSD) and measured t...

Phleomycin induced DNA breakage was investigated with superhelical Col. E1 DNA and linear T2 DNA as well. In both DNA-forms besides single-strand breaks direct double-strand breaks were produced by the drug. The double-strand breakage rate obtained after treatment with phleomycin, however, was considerably smaller than that found after bleomycin treatment. Whereas the single- and double-strand ...

Fragile site breakage was previously shown to result in rearrangement of the RET oncogene, resembling the rearrangements found in thyroid cancer. Common fragile sites are specific regions of the genome with a high susceptibility to DNA breakage under conditions that partially inhibit DNA replication, and often coincide with genes deleted, amplified, or rearranged in cancer. While a substantial ...

We demonstrate that the topoisomerase activity of bacteriophage lambda Int protein introduces single-strand breaks into duplex DNA at specific sites. Strand breakage is accompanied by the covalent linkage of Int to DNA. The linkage connects a residue in Int to the 3' phosphate of DNA at the site of breakage; the other breakage product has a 5' OH terminus. Int is the first procaryotic topoisome...

The esperamicins represent a class of antitumor antibiotics characterized by an unusual chemical core structure and extremely potent cytotoxicity. The mechanism by which these drugs produce cytotoxicity was investigated and found to be related to the formation of single- and double-strand DNA breaks. Using five structurally related analogs, we defined a structure-activity relationship for cytot...