An uncertain role for Cu(II) in stimulating Mn(II) oxidation by Leptothrix discophora SS-1
Iman A El Gheriany1, Daniela Bocioaga, Anthony G Hay
1School of Chemical and Biomolecular Engineering, Olin Hall, Cornell University, Ithaca, NY 14853, USA.
Archives of Microbiology
|November 11, 2010
Summary
Copper (Cu(II)) significantly enhances bacterial manganese (Mn(II)) oxidation in Leptothrix discophora SS-1. However, the precise role of copper and its effect on the mofA gene remain unclear.
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Bacterial oxidation of manganese (Mn(II)) is crucial in biogeochemical cycles.
- The role of copper (Cu(II)) in this process is not fully understood.
- Leptothrix discophora SS-1 is a model organism for studying Mn(II) oxidation.
Purpose of the Study:
- To investigate the specific role of Cu(II) in bacterial Mn(II) oxidation.
- To determine if metal toxicity influences Mn(II) oxidizing activity.
- To examine the effect of Cu(II) on the expression of the mofA gene.
Main Methods:
- Culturing Leptothrix discophora SS-1 in the presence of varying concentrations of Cu(II), Cadmium (Cd(II)), and Mn(II).
- Measuring Mn(II)-oxidizing activity.
- Comparing transcript levels of the multicopper oxidase mofA gene under different conditions.
Main Results:
- Mn(II)-oxidizing activity increased by 40% at 0.05 microM Cu(II) and twofold at 0.18 microM Cu(II).
- Toxic levels of Cd(II) did not stimulate Mn(II) oxidizing activity.
- No statistically significant change in mofA transcript levels was observed with Cu(II) supplementation.
Conclusions:
- Cu(II) specifically stimulates bacterial Mn(II) oxidation, suggesting a direct role.
- Mn(II) oxidation is not a general response to metal toxicity.
- The exact mechanism of Cu(II) action and its impact on mofA gene expression require further investigation.
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