The effect of Mn on the expression of the manganese oxidizing protein in Erythrobacter sp. SD21
Mentor:Hope Johnson, Assistant Professor , Cal State University, Fullerton
Toxic metals easily accumulate in water sources and pose serious dangers to human health and the environment. Manganese-oxidizing bacteria, such as [i]Erythrobacter[/i] sp. strain SD-21, can produce useful manganese oxides that can be directed as a bioremediation solution. The production of crystal Mn oxides coat the surface of bacterial cells and allow for adhesion of metal ions and sequestration of toxic heavy metals. However, very little is known about the biochemical mechanisms for the formation of Mn(II) to Mn(III and IV) oxides. In addition, the adsorptive property of Mn(IV) oxides can also contribute to the global cycling of nutrients. Therefore, it is critical to gain a more complete understanding of the biochemical mechanisms responsible for bacterial manganese oxidation. The regulation of managnese oxidation was studied by finding an association between environmental conditions and Mn(II) oxidation with a gene involved in manganese oxidation called [i]mopA[/i]. Our research studies have shown that [i]mopA[/i] gene expression is affected when [i]Erythrobacter[/i] sp. strain SD-21 are stressed with hydrogen peroxide. [i]Erythrobacter[/i] sp. SD-21 cells were shocked with a high concentration of manganese chloride to see if this also changes the expression of the [i]mopA[/i] gene. A change in gene expression is expected because [i]mopA[/i] is responsible for Mn(II) oxidation to Mn(III and IV). mRNA was extracted from the shocked bacterial cells and reverse transcribed into cDNA. With the cDNA, a qPCR will be performed to determine how [i]mopA[/i] responds to manganese chloride. Manganese-oxidizing bacteria may be beneficial to remove or neutralize contamination in the soil and water caused by the presence of harmful toxic metals.