Enzymatic formation of manganese oxides by an Acremonium-like hyphomycete fungus, strain KR21-2

Miyata, Naoyuki; Tani, Yukinori; Iwahori, Keisuke; Soma, Mitsuyuki

doi:10.1016/s0168-6496(03)00251-4

Cited by 120 publications

(115 citation statements)

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“…Thus, the reason microbes expend energy to enzymatically oxidize Mn(II) is presently unknown (7) and brings into question any evolutionary basis for this process. The Mn(II)-oxidizing Ascomycota belong to a number of different genera, such as Pyrenochaeta, Alternaria, Phoma, and Acremonium (11,12). Although the mechanism of Mn(II) oxidation by Ascomycete fungi remains unknown, the multicopper oxidase enzyme laccase has been implicated recently (11).…”

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confidence: 99%

“…The Mn(II)-oxidizing Ascomycota belong to a number of different genera, such as Pyrenochaeta, Alternaria, Phoma, and Acremonium (11,12). Although the mechanism of Mn(II) oxidation by Ascomycete fungi remains unknown, the multicopper oxidase enzyme laccase has been implicated recently (11). Multicopper oxidases are a structurally and functionally diverse family of enzymes that have the capacity to oxidize a wide range of organic and inorganic substrates [e.g., Fe(II), diphenolics] (13).…”

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confidence: 99%

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Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Hansel

Zeiner

Santelli

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

194

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Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa , oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium ( Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems.

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confidence: 99%

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confidence: 99%

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Hansel

Zeiner

Santelli

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

194

161

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“…[1][2][3] In such places, pH is mostly in the range of 6-8 where Mn (II) ions are not capable to be chemically oxidized by oxygen. Several kinds of Mnoxidizing bacteria, such as Leptothrix, Arthrobactor, Bacillus, Pseudomonas, Micrococcus, 4) and a few kinds of Mnoxidizing fungi, 5,6) were isolated from fresh water, sea water, hydrothermal vents and sediments, and identified by morphological and genetic investigations.…”

Section: Introductionmentioning

confidence: 99%

“…6) Besides, the maximum Mn-oxidizing rate for the strain KR21-2 of the Acremonium-like hyphomycete fungus revealed at 165 gÁm À3 of the initial Mn(II) ion concentration was reduced to nearly zero at 275 gÁm À3 . 5) On the contrary, the optimum condition for the Mn-oxidizing bacteria Leptothrix discophora was around 8 gÁm À3 of the initial Mn ion concentration, which is under the maximum contamination limit (MCL) for Mn in discharge water in Japan. The fungal cell wall, which is mainly composed of chitin, is mechanically stronger than that of bacteria and has a superior capacity for the accumulation of fine particles.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Mn(II) Ions by a Mn-Oxidizing Fungus <I>Paraconiothyrium sp.-Like</I> Strain at Neutral pHs

et al. 2006

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A Mn-oxidizing fungus was isolated from a constructed wetland of Hokkaido (Japan), which is receiving the Mn-impacted drainage, and genetically and morphologically identified as Paraconiothyrium sp.-like strain. The optimum pHs were 6.45-6.64, where is more acidic than those of previously reported Mn-oxidizing fungi. Too much nutrient inhibited fungal Mn-oxidation, and too little nutrient also delayed Mn oxidation even at optimum pH. In order to achieve the oxidation of high concentrations of Mn like mine drainage containing several hundreds gÁm À3 of Mn, it is important to find the best mix ratio among the initial Mn concentrations, inoculumn size and nutrient concentration. The strain has still Mn-tolerance with more than 380 gÁm À3 of Mn, but high Mn(II) oxidation was limited by pH control and supplied nutrient amounts. The biogenic Mn deposit was poorly crystallized birnessite. The strain is an unique Mn-oxidizing fungus having a high Mn tolerance and weakly acidic tolerance, since there has been no record about the property of the strain. There is a potentiality to apply the strain to the environmental bioremediation.

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“…14,15 Even less is known about fungal MnO x . 16,17 Traditionally the three-dimensional (3D) structure of materials is determined by measuring and analyzing the positions and intensities of the Bragg peaks in their XRD patterns. 18 Traditional (i.e.…”

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Atomic-Scale Structure of Biogenic Materials by Total X-ray Diffraction: A Study of Bacterial and Fungal MnO_x

et al. 2009

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C urrently, technology is looking for smaller scale, ordered materials with well-defined properties. Nanophase materials are, therefore, being manufactured in increasing numbers. 1Ϫ3 Nature is also a prolific producer of nanophase materials. A typical example of this is the microorganism assisted, or biogenic, oxidation of water-soluble metal ions into insoluble oxides. 4 Indeed this process has been taking place for millions of years leaving its signature all around: in the sediments on the ocean floor and in the soil on land. Nature's evident success is inspiring and scientists are trying to employ its tools for applications including manufacturing of magnetic nanoparticles 5 and capturing of contaminant metal ions. 6Ϫ8 Thus understanding the way living microorganisms produce materials, in particular nanophase metal oxides, is becoming important not only for the advance of today's technology but also for remediating some of its unwanted consequences such as metal pollution.One of the most important prerequisites to understanding a physicochemical process, such as the formation of a nanophase material, is the knowledge of the atomic-scale structure of its product. Recently, good progress has been made in determining the structure of synthetic (i.e., man-made) nanophase materials by employing total X-ray diffraction (XRD) involving a combination of high-energy XRD and atomic pair distribution function (PDF) analysis. 9Ϫ11 This nontraditional approach has also been applied to nanophase materials of geological interest, such as ores. 12 The approach can also be applied to materials freshly produced by living microorganisms. As an example we consider MnO x produced by bacteria and fungi. These biogenic materials show a length of structural coherence of about 2Ϫ3 nm only and, in this sense, are in a nanophase state. Nevertheless, their atomic-scale structure is periodic and can be described in simple crystallographic terms. Surprisingly the crystal structures of fungal and bacterial MnO x turn out to be substantially different indicating that biogenic materials are inherently structurally diverse.Manganese oxides are ubiquitous in nature 13 and have been used by mankind for many thousands of yearsOfirst as pigments and today as catalysts and battery materials. This has generated a long-lasting interest in their genesis. Several studies on MnO x produced by microorganisms have been carried out but no complete structural determination has yet been performed. The studies have only suggested that bacterial MnO x is likely to possess a layered-type structure of the type found in the mineral birnessite. 14,15 Even less is known about fungal MnO x . 16,17 *Address correspondence to petkov@phy.cmich.edu. As such, they are difficult to characterize structurally. In this report, we demonstrate how high-energy X-ray diffraction and atomic pair distribution function analysis can be used to determine the atomic-scale structures of MnO x produced by bacteria and fungi. These structures are well-defined, periodic, and species-sp...

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Enzymatic formation of manganese oxides by an Acremonium-like hyphomycete fungus, strain KR21-2

Cited by 120 publications

References 42 publications

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Immobilization of Mn(II) Ions by a Mn-Oxidizing Fungus <I>Paraconiothyrium sp.-Like</I> Strain at Neutral pHs

Atomic-Scale Structure of Biogenic Materials by Total X-ray Diffraction: A Study of Bacterial and Fungal MnO_x

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Enzymatic formation of manganese oxides by an Acremonium-like hyphomycete fungus, strain KR21-2

Cited by 120 publications

References 42 publications

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Immobilization of Mn(II) Ions by a Mn-Oxidizing Fungus <I>Paraconiothyrium sp.-Like</I> Strain at Neutral pHs

Atomic-Scale Structure of Biogenic Materials by Total X-ray Diffraction: A Study of Bacterial and Fungal MnOx

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Atomic-Scale Structure of Biogenic Materials by Total X-ray Diffraction: A Study of Bacterial and Fungal MnO_x