An uncertain role for Cu(II) in stimulating Mn(II) oxidation by Leptothrix discophora SS-1

Abstract

In an effort to improve understanding of the role of Cu(II) in bacterial Mn(II) oxidation, a model Mn(II)-oxidizing bacterium, Leptothrix discophora SS-1, was grown in presence of toxic and non-toxic concentrations of Cu(II), Cd(II) and Mn(II). Mn(II)-oxidizing activity increased by 40% when cells were grown in the presence of 0.05 microM of Cu(II) and increased twofold at 0.18 microM Cu(II). Toxic levels of Cd(II) did not stimulate Mn(II) oxidizing activity, indicating that Mn(II) oxidation is not a response to metal toxicity. Stimulation by Cu(II) confirms the specific role of Cu(II) in Mn(II) oxidation. Comparison of transcript levels of the multicopper oxidase mofA gene in the presence and absence of added Cu(II) do not indicate a statistically significant change in mofA transcript levels in cultures supplemented with Cu(II). Thus, the exact role of Cu(II) in Mn(II) oxidation and its affect on mofA gene expression remain uncertain.

CotA, a Multicopper Oxidase from Bacillus pumilus WH4, Exhibits Manganese-Oxidase Activity

“…It coincided pretty well with the previous studies that copper indeed had a profound stimulating effect on the oxidation of Mn(II) [41]. This positive role of Cu 2+ might be interpreted by the possibility that Cu 2+ was the essential cofactor and enhanced the folding of CotA (Figure S7) [42].…”

Preparation and properties of ferrite derived from iron oxidizing bacteria

“…Figure 2a shows that the single bacterial cells account for a large percentage, with obvious agglomeration; while in Figure 2b, there is a marked absence of clothing and cell sheath. Although Leptothrix discophora (ATCC43182) itself does not have clothes sheath [9], but in the latter part of the training process, there will be variations in the cell, thus forming clothing sheath. The iron deposition medium and MMS media were used further to inoculate the Sphaerotilus natans and the Leptothrix discophora, respectively.…”

“…This microbe could be directly used to obtain composites with a variety of shapes such as fiber, tube and film [7][8][9][10][11][12][13][14][15][16] and has the potential to fabricate the ferrite materials. Compared to traditional chemical synthesis [5], there may be a breakthrough in the aspects of physical control, particle reunion and industrialization.In this paper, according to the enrichment and deposition mechanism of iron and manganese [7][8][9][10][11][12], the sediment composition, the microstructure characteristics [15] and other basic research of iron bacteria, the Sphaerotilus natans which were separated from activity mud of Xiamen sewage treatment plant and the Leptothrix discophora which was purchased from ATCC, were used to deposit the iron and manganese ions respectively. The Sediments were collected and heat treated at high temperature to obtain the ferrite.…”

“…It was shown that iron bacteria are widespread in various types of nature waters, which have the capacity of oxidizing and depositing ferrous ions and manganese ions in water efficiently. This microbe could be directly used to obtain composites with a variety of shapes such as fiber, tube and film [7][8][9][10][11][12][13][14][15][16] and has the potential to fabricate the ferrite materials. Compared to traditional chemical synthesis [5], there may be a breakthrough in the aspects of physical control, particle reunion and industrialization.…”

“…In this paper, according to the enrichment and deposition mechanism of iron and manganese [7][8][9][10][11][12], the sediment composition, the microstructure characteristics [15] and other basic research of iron bacteria, the Sphaerotilus natans which were separated from activity mud of Xiamen sewage treatment plant and the Leptothrix discophora which was purchased from ATCC, were used to deposit the iron and manganese ions respectively. The Sediments were collected and heat treated at high temperature to obtain the ferrite.…”