Publication Date:
2011-06-10
Description:
Plasmid DNA was incubated at 25°C with aqueous solutions of dissolved Fe(II), S(-II), and nanoparticulate FeS with a mackinawite structure, FeS m . At ≥0.1 mM total dissolved Fe(II) and S(-II), an increase in the proportion of the relaxed plasmid DNA occurs, through scission of the DNA backbone. In solutions where FeS m was precipitated, nanoparticulate FeS m binds to the DNA molecules. In solutions with concentrations below the FeS m solubility product, nicking of supercoiled pDNA occurs. Plasmid DNA appears to be a sensitive proxy for radical reactions. The reactant is proposed to be a sulfur-based radical produced from the iron-catalyzed decomposition of bisulfide, in a manner analogous to the Fenton reaction. This is further supported by experiments that suggest that sulfide free radicals are produced during the photolysis of aqueous solutions of polysulfides. Supercoiling of DNA affects nearly all DNA–protein transactions so the observation of relaxation of supercoiled forms through reaction with FeS solutions has direct implications to biochemistry. The results of this experimentation suggest that genotoxicity in FeS-rich systems is a further contributory factor to the limited survival of organisms in sulfidic environments. Mutations resulting from the interactions of organisms and mobile elements, such as plasmids, in sediments will also be affected in sulfide-rich environments. Content Type Journal Article Pages 1-22 DOI 10.1007/s10498-010-9116-x Authors D. Rickard, School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF103YE UK B. Hatton, School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF103YE UK D. M. Murphy, School of Chemistry, Cardiff University, Cardiff, CF103YE UK I. B. Butler, School of Geosciences, University of Edinburgh, Edinburgh, EH9 3JW UK A. Oldroyd, School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF103YE UK A. Hann, School of Biosciences, Cardiff University, Cardiff, CF103YE UK Journal Aquatic Geochemistry Online ISSN 1573-1421 Print ISSN 1380-6165
Print ISSN:
1380-6165
Electronic ISSN:
1573-1421
Topics:
Chemistry and Pharmacology
,
Geosciences
