Mechanisms of Chromium-Induced Toxicity.

Chromium is a pervasive environmental contaminant that is of great importance because of its toxicity. Hexavalent chromium is a classified group 1 carcinogen with multiple complex mechanisms by which it triggers cancer development. Increased levels of oxidative stress, chromosome breaks, and DNA-adduct formation are some of the major mechanisms by which C(VI) causes cellular damage.

Malignant human cell transformation of Marcellus Shale gas drilling flow back water.

The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed.

Oxidative stress alters global histone modification and DNA methylation.

The JmjC domain-containing histone demethylases can remove histone lysine methylation and thereby regulate gene expression. The JmjC domain uses iron Fe(II) and α-ketoglutarate (αKG) as cofactors in an oxidative demethylation reaction via hydroxymethyl lysine. We hypothesize that reactive oxygen species will oxidize Fe(II) to Fe(III), thereby attenuating the activity of JmjC domain-containing histone demethylases.