Table of Contents Author Guidelines Submit a Manuscript
International Journal of Microbiology
Volume 2014 (2014), Article ID 394835, 11 pages
http://dx.doi.org/10.1155/2014/394835
Research Article

Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction

1Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA
2Department of Biochemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
3School of Geography and Geosciences, University of St Andrews, St Andrews, Fife KY16 9AX, UK
4Department of Biology, North Carolina Central University, Durham, NC 27707, USA

Received 29 December 2013; Revised 28 February 2014; Accepted 16 March 2014; Published 15 April 2014

Academic Editor: Alfons J. M. Stams

Copyright © 2014 Antonia Y. Tetteh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by 50% while 0.001 to 0.01 mM treatments stimulated cell growth by 30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S) metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.