Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqu...

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Main Authors:	Kunoh, Tatsuki, Hashimoto, Hideki, McFarlane, Ian R., Hayashi, Naoaki, Suzuki, Tomoko, Taketa, Eisuke, Tamura, Katsunori, Takano, Mikio, El-Naggar, Mohamed Y., Kunoh, Hitoshi, Takada, Jun
Format:	Online
Language:	English
Published:	MDPI 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929540/

id	pubmed-4929540
recordtype	oai_dc
spelling	pubmed-49295402016-07-07 Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths Kunoh, Tatsuki Hashimoto, Hideki McFarlane, Ian R. Hayashi, Naoaki Suzuki, Tomoko Taketa, Eisuke Tamura, Katsunori Takano, Mikio El-Naggar, Mohamed Y. Kunoh, Hitoshi Takada, Jun Article Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. MDPI 2016-06-03 /pmc/articles/PMC4929540/ /pubmed/27271677 http://dx.doi.org/10.3390/biology5020026 Text en © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Kunoh, Tatsuki Hashimoto, Hideki McFarlane, Ian R. Hayashi, Naoaki Suzuki, Tomoko Taketa, Eisuke Tamura, Katsunori Takano, Mikio El-Naggar, Mohamed Y. Kunoh, Hitoshi Takada, Jun
spellingShingle	Kunoh, Tatsuki Hashimoto, Hideki McFarlane, Ian R. Hayashi, Naoaki Suzuki, Tomoko Taketa, Eisuke Tamura, Katsunori Takano, Mikio El-Naggar, Mohamed Y. Kunoh, Hitoshi Takada, Jun Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
author_facet	Kunoh, Tatsuki Hashimoto, Hideki McFarlane, Ian R. Hayashi, Naoaki Suzuki, Tomoko Taketa, Eisuke Tamura, Katsunori Takano, Mikio El-Naggar, Mohamed Y. Kunoh, Hitoshi Takada, Jun
author_sort	Kunoh, Tatsuki
title	Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
title_short	Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
title_full	Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
title_fullStr	Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
title_full_unstemmed	Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
title_sort	abiotic deposition of fe complexes onto leptothrix sheaths
description	Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths.
publisher	MDPI
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929540/
_version_	1613602915812900864

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

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