Amending Cultures of Selenium-Resistant Bacteria with Dimethyl Selenone

Limin Zhang and Thomas G. Chasteen*

Department of Chemistry, Sam Houston State University

Applied Organometallic Chemistry, 1994, Vol. 8(6), pages 501-508.


Abstract

A possible biological intermediate in the reduction and methylation of selenium oxyanions, dimethyl selenone, was synthesized, and the first experiments involving the amendment of selenium resistant bacterial cultures with this compound are reported. The amount of volatile, reduced selenium containing species released from these cultures into the headspace is significantly more than that produced in analogous experiments involving sodium selenate amended cultures. Dimethyl selenone is reduced in the presence of dimethyl sulfide and dimethyl disulfide in a complex growth medium, trypticase soy broth with 0.1 % nitrate. This reduction occurs whether or not the reduced sulfur compounds are biologically produced.
Comparison between the bacterial reduction of 1) selenate (a selenium oxyanion) and 2) dimethyl selenone from this research is available here.

Dimethyl selenone was proposed over fifty years ago by Frederick Challenger (at the University of Leeds) as a biological intermediate in the sequential reduction and methylation of oxyanions of selenium. A chromatogram showing the chemical reduction of dimethyl selenone by "inorganic" dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) is an interesting datum from this work.