This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Leang, C.
Right arrow Articles by Lovley, D. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Leang, C.
Right arrow Articles by Lovley, D. R.

 Previous Article  |  Next Article 

Journal of Bacteriology, September 2005, p. 5918-5926, Vol. 187, No. 17
0021-9193/05/$08.00+0     doi:10.1128/JB.187.17.5918-5926.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Adaptation to Disruption of the Electron Transfer Pathway for Fe(III) Reduction in Geobacter sulfurreducens

Ching Leang,1* L. A. Adams,1 K.-J. Chin,1 K. P. Nevin,1 B. A. Methé,2 J. Webster,2 M. L. Sharma,1 and D. R. Lovley1

Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003,1 The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, Maryland 208502

Received 29 March 2005/ Accepted 17 June 2005

Previous studies demonstrated that an outer membrane c-type cytochrome, OmcB, was involved in Fe(III) reduction in Geobacter sulfurreducens. An OmcB-deficient mutant was greatly impaired in its ability to reduce both soluble and insoluble Fe(III). Reintroducing omcB restored the capacity for Fe(III) reduction at a level proportional to the level of OmcB production. Here, we report that the OmcB-deficient mutant gradually adapted to grow on soluble Fe(III) but not insoluble Fe(III). The adapted OmcB-deficient mutant reduced soluble Fe(III) at a rate comparable to that of the wild type, but the cell yield of the mutant was only ca. 60% of that of the wild type under steady-state culturing conditions. Analysis of proteins and transcript levels demonstrated that expression of several membrane-associated cytochromes was higher in the adapted mutant than in the wild type. Further comparison of transcript levels during steady-state growth on Fe(III) citrate with a whole-genome DNA microarray revealed a significant shift in gene expression in an apparent attempt to adapt metabolism to the impaired electron transport to Fe(III). These results demonstrate that, although there are many other membrane-bound c-type cytochromes in G. sulfurreducens, increased expression of these cytochromes cannot completely compensate for the loss of OmcB. The concept that outer membrane cytochromes are promiscuous reductases that are interchangeable in function appears to be incorrect. Furthermore, the results indicate that there may be different mechanisms for electron transfer to soluble Fe(III) and insoluble Fe(III) oxides in G. sulfurreducens, which emphasizes the importance of studying electron transport to the environmentally relevant Fe(III) oxides.

* Corresponding author. Mailing address: Department of Microbiology, 203 Morrill Science Center IVN, University of Massachusetts at Amherst, Amherst, MA 01003. Phone: (413) 577-1251. Fax: (413) 545-1578. E-mail: leang{at}microbio.umass.edu.

Journal of Bacteriology, September 2005, p. 5918-5926, Vol. 187, No. 17
0021-9193/05/$08.00+0     doi:10.1128/JB.187.17.5918-5926.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Rollefson, J. B., Levar, C. E., Bond, D. R. (2009). Identification of Genes Involved in Biofilm Formation and Respiration via Mini-Himar Transposon Mutagenesis of Geobacter sulfurreducens. J. Bacteriol. 191: 4207-4217 [Abstract] [Full Text]  
  • Marsili, E., Rollefson, J. B., Baron, D. B., Hozalski, R. M., Bond, D. R. (2008). Microbial Biofilm Voltammetry: Direct Electrochemical Characterization of Catalytic Electrode-Attached Biofilms. Appl. Environ. Microbiol. 74: 7329-7337 [Abstract] [Full Text]  
  • Jiao, Y., Newman, D. K. (2007). The pio Operon Is Essential for Phototrophic Fe(II) Oxidation in Rhodopseudomonas palustris TIE-1. J. Bacteriol. 189: 1765-1773 [Abstract] [Full Text]  
  • Kappler, A., Straub, K. L. (2005). Geomicrobiological Cycling of Iron. Reviews in Mineralogy and Geochemistry 59: 85-108 [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»