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Diphenyl ditelluride (DPDT) is a potential prototype for the development of novel biologically active molecules. Thus, it is important to evaluate the toxic effects of this compound. In the present study, we evaluated the cytotoxic, genotoxic and mutagenic properties of DPDT in Chinese hamster fibroblast (V79) cells, in strains of the yeast Saccharomyces cerevisiae both proficient and deficient in several DNA repair pathways and in Salmonella typhimurium. DPDT induced frameshift mutations in both S.typhimurium and a haploid wild-type strain of S.cerevisiae. Mutants of S.cerevisiae defective in base excision repair and recombinational repair were more sensitive to DPDT. The results of a lactate dehydrogenase leakage assay suggest that DPDT is cytotoxic to V79 cells. At cytotoxic concentrations, this compound increased thiobarbituric reactive species levels and decreased the glutathione:GSSH ratio in yeast and V79 cells. DPDT generated single- and double-strand DNA breaks in V79 cells, both with and without metabolic activation, as revealed by alkaline and neutral comet assays. Moreover, an induction of oxidative DNA base damage was indicated by a modified comet assay using formamidopyrimidine DNA glycosylase and endonuclease III. Treatment with DPDT also induced micronucleus formation in V79 cells. Pre-incubation with N-acetylcysteine reduced DPDT's oxidative, genotoxic and mutagenic effects in yeast and V79 cells. Our results suggest that the toxic and mutagenic properties of DPDT may stem from its ability to disturb the redox balance of the cell, which leads to oxidative stress and the induction of DNA damage.

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Exposure to coal and coal ashes can cause harmful effects in in vitro and in vivo systems, mainly by the induction of oxidative damage. The aim of this work was to assess cytotoxic and genotoxic effects using the V79 cell line treated with coal and coal fly ash particles derived from a coal power plant located in Santa Catarina, Brazil. Two coal samples (COAL11 and COAL16) and two coal fly ash samples (CFA11 and CFA16) were included in this study. COAL16 was co-firing with a mixture of fuel oil and diesel oil. The comet assay data showed that exposure of V79 cells to coal and coal fly ash particles induced primary DNA lesions. Application of lesion-specific endonucleases (FPG and ENDO III) demonstrated increased DNA effects indicating the presence of high amounts of oxidative DNA lesions. The cytokinesis-block micronucleus cytome assay analysis showed that exposure of V79 cells to high concentrations of coal and coal fly ash particles induced cytotoxic effects (apoptosis and necrosis) and chromosomal instability (nucleoplasmic bridges, nuclear buds, and micronucleus (MN) formation). These results may be associated with compounds contained in the surface of the particles as hazardous elements, ultrafine/nanoparticles, and polycyclic aromatic hydrocarbons (PAHs) which were detected in the samples. Graphical abstract ᅟ.