Next Article in Journal
Nothing in Evolution Makes Sense Except in the Light of Genomics: Read–Write Genome Evolution as an Active Biological Process
Previous Article in Journal
The Unicellular State as a Point Source in a Quantum Biological System
Article Menu

Export Article

Open AccessArticle
Biology 2016, 5(2), 26;

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Okayama 700-0082, Japan
Graduate School of Natural Science and Technology, Okayama University, Okayama 700-0082, Japan
Department of Applied Chemistry, School of Advanced Engineering, Kogakuin University, Hachiohji, Tokyo 192-0015, Japan
Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
Department of Chemical and Biological Science, Japan Woman’s University, Bunkyo-ku, Tokyo 112-8681, Japan
Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
Authors to whom correspondence should be addressed.
Academic Editor: Jukka Finne
Received: 21 April 2016 / Revised: 26 May 2016 / Accepted: 27 May 2016 / Published: 3 June 2016
Full-Text   |   PDF [3313 KB, uploaded 3 June 2016]   |  


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. View Full-Text
Keywords: Leptothrix cholodnii SP-6; abiotic oxidation; Fe(III) particles; sheath; direct deposition Leptothrix cholodnii SP-6; abiotic oxidation; Fe(III) particles; sheath; direct deposition

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Kunoh, T.; Hashimoto, H.; McFarlane, I.R.; Hayashi, N.; Suzuki, T.; Taketa, E.; Tamura, K.; Takano, M.; El-Naggar, M.Y.; Kunoh, H.; Takada, J. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths. Biology 2016, 5, 26.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Biology EISSN 2079-7737 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top