scholarly journals Ferrous Iron and Sulfur Oxidation and Ferric Iron Reduction Activities of Thiobacillus ferrooxidans Are Affected by Growth on Ferrous Iron, Sulfur, or a Sulfide Ore

1990 ◽  
Vol 56 (6) ◽  
pp. 1620-1626 ◽  
Author(s):  
Isamu Suzuki ◽  
Travis L. Takeuchi ◽  
Trin D. Yuthasastrakosol ◽  
Jae Key Oh
Keyword(s):  
Ferrous Iron ◽  
Iron Reduction ◽  
Ferric Iron ◽  
Thiobacillus Ferrooxidans ◽  
Sulfur Oxidation ◽  
Iron Sulfur ◽  
Sulfide Ore ◽  
Iron And Sulfur Oxidation

Changes in Acidithiobacillus ferrooxidans Ability to Reduce Ferric Iron by Elemental Sulfur

2015 ◽  
Vol 1130 ◽  
pp. 97-100 ◽  
Author(s):  
Jiri Kucera ◽  
Eva Pakostova ◽  
Oldrich Janiczek ◽  
Martin Mandl
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Proteomic Analysis ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
Elemental Sulfur ◽  
Ferric Iron ◽  
Sulfur Metabolism ◽  
Sulfur Oxidation ◽  
Quinone Reductase ◽  
Heterodisulfide Reductase

Ferric iron may act as a thermodynamically favourable electron acceptor during elemental sulfur oxidation byAcidithiobacillus ferrooxidansin extremely acidic anoxic environments. A loss of anaerobic ferric iron reduction ability has been observed in ferrous iron-grownA. ferrooxidansCCM 4253 after aerobic passaging on elemental sulfur. In this study, iron-oxidising cells aerobically adapted from ferrous iron to elemental sulfur were still able to anaerobically reduce ferric iron, however, following aerobic passage on elemental sulfur it could not. Preliminary quantitative proteomic analysis of whole cell lysates of the passage that lost anaerobic ferric iron-reducing activity resulted in 150 repressed protein spots in comparison with the antecedent culture, which retained the activity. Identification of selected protein spots by tandem mass spectrometry revealed physiologically important proteins including rusticyanin and outer-membrane cytochrome Cyc2, which are involved in iron oxidation. Other proteins were associated with sulfur metabolism such as sulfide-quinone reductase and proteins encoded by the thiosulfate dehydrogenase and heterodisulfide reductase complex operons. Furthermore, proteomic analysis identified proteins directly related to anaerobiosis. The results indicate the importance of iron-oxidising system components for anaerobic sulfur oxidation in the studied microbial strain.

Inhibition of growth, iron, and sulfur oxidation in Thiobacillus ferrooxidans by simple organic compounds

1976 ◽  
Vol 22 (5) ◽  
pp. 719-730 ◽  
Author(s):  
Jon H. Tuttle ◽  
Patrick R. Dugan
Keyword(s):  
Organic Compounds ◽  
Ferrous Iron ◽  
Thiobacillus Ferrooxidans ◽  
Cell Envelope ◽  
Iron Oxidation ◽  
Inorganic Ions ◽  
Sulfur Oxidation ◽  
Physical Treatment ◽  
Inhibition Of Growth ◽  
Iron And Sulfur Oxidation

Iron and sulfur oxidation by Thiobacillus ferrooxidans as well as growth on ferrous iron were inhibited by a variety of low molecular weight organic compounds. The influences of chemical structure of the organic inhibitors, pH, temperature, physical treatment of cells, and added inhibitory or stimulatory inorganic ions and iron oxidation suggest that a major factor contributing to the inhibitory effects on iron oxidation is the relative electronegativity of the organic molecule. The data also suggest that inhibitory organic compounds may (i) directly affect the iron-oxidizing enzyme system, (ii) react abiologically with ferrous iron outside the cell, (iii) interfere with the roles of phosphate and sulfate in iron oxidation, and (iv) nonselectively disrupt the cell envelope or membrane.

scholarly journals Vibrio cholerae VciB Mediates Iron Reduction

2017 ◽  
Vol 199 (12) ◽  
Author(s):  
Eric D. Peng ◽  
Shelley M. Payne
Keyword(s):  
Electron Transport ◽  
Vibrio Cholerae ◽  
Ferrous Iron ◽  
Electron Transport Chain ◽  
Iron Reduction ◽  
Iron Transport ◽  
Ferric Iron ◽  
Transport Systems ◽  
Content Type ◽  
Transport Chain

ABSTRACT Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. V. cholerae thrives within the human host, where it replicates to high numbers, but it also persists within the aquatic environments of ocean and brackish water. To survive within these nutritionally diverse environments, V. cholerae must encode the necessary tools to acquire the essential nutrient iron in all forms it may encounter. A prior study of systems involved in iron transport in V. cholerae revealed the existence of vciB, which, while unable to directly transport iron, stimulates the transport of iron through ferrous (Fe2+) iron transport systems. We demonstrate here a role for VciB in V. cholerae in which VciB stimulates the reduction of Fe3+ to Fe2+, which can be subsequently transported into the cell with the ferrous iron transporter Feo. Iron reduction is independent of functional iron transport but is associated with the electron transport chain. Comparative analysis of VciB orthologs suggests a similar role for other proteins in the VciB family. Our data indicate that VciB is a dimer located in the inner membrane with three transmembrane segments and a large periplasmic loop. Directed mutagenesis of the protein reveals two highly conserved histidine residues required for function. Taken together, our results support a model whereby VciB reduces ferric iron using energy from the electron transport chain. IMPORTANCE Vibrio cholerae is a prolific human pathogen and environmental organism. The acquisition of essential nutrients such as iron is critical for replication, and V. cholerae encodes a number of mechanisms to use iron from diverse environments. Here, we describe the V. cholerae protein VciB that increases the reduction of oxidized ferric iron (Fe3+) to the ferrous form (Fe2+), thus promoting iron acquisition through ferrous iron transporters. Analysis of VciB orthologs in Burkholderia and Aeromonas spp. suggest that they have a similar activity, allowing a functional assignment for this previously uncharacterized protein family. This study builds upon our understanding of proteins known to mediate iron reduction in bacteria.

Influence of dietary phenolic acids on redox status of iron: Ferrous iron autoxidation and ferric iron reduction

2008 ◽  
Vol 106 (2) ◽  
pp. 650-660 ◽  
Author(s):  
Kateřina Chvátalová ◽  
Iva Slaninová ◽  
Lenka Březinová ◽  
Jiří Slanina
Keyword(s):  
Phenolic Acids ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
Ferric Iron ◽  
Redox Status

scholarly journals Ferrihydrite-Dependent Growth of Sulfurospirillum deleyianum through Electron Transfer via Sulfur Cycling

2004 ◽  
Vol 70 (10) ◽  
pp. 5744-5749 ◽  
Author(s):  
Kristina L. Straub ◽  
Bernhard Schink
Keyword(s):  
Electron Acceptor ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
Ferric Iron ◽  
Sulfide Oxidation ◽  
Microbial Reduction ◽  
Sulfur Cycle ◽  
Sulfur Cycling ◽  
Sulfur Source ◽  
Sulfur Species

ABSTRACT Observations in enrichment cultures of ferric iron-reducing bacteria indicated that ferrihydrite was reduced to ferrous iron minerals via sulfur cycling with sulfide as the reductant. Ferric iron reduction via sulfur cycling was investigated in more detail with Sulfurospirillum deleyianum, which can utilize sulfur or thiosulfate as an electron acceptor. In the presence of cysteine (0.5 or 2 mM) as the sole sulfur source, no (microbial) reduction of ferrihydrite or ferric citrate was observed, indicating that S. deleyianum is unable to use ferric iron as an immediate electron acceptor. However, with thiosulfate at a low concentration (0.05 mM), growth with ferrihydrite (6 mM) was possible and sulfur was cycled up to 60 times. Also, spatially distant ferrihydrite in agar cultures was reduced via diffusible sulfur species. Due to the low concentrations of thiosulfate, S. deleyianum produced only small amounts of sulfide. Obviously, sulfide delivered electrons to ferrihydrite with no or only little precipitation of black iron sulfides. Ferrous iron and oxidized sulfur species were produced instead, and the latter served again as the electron acceptor. These oxidized sulfur species have not yet been identified. However, sulfate and sulfite cannot be major products of ferrihydrite-dependent sulfide oxidation, since neither compound can serve as an electron acceptor for S. deleyianum. Instead, sulfur (elemental S or polysulfides) and/or thiosulfate as oxidized products could complete a sulfur cycle-mediated reduction of ferrihydrite.

scholarly journals Dispersion of sulfur enables sulfur oxidation before iron oxidation in Acidithiobacillus ferrooxidans: A valuable formulation for the genetic engineering toolbox

2021 ◽  
Author(s):  
Yuta Inaba ◽  
Timothy Kernan ◽  
Alan West ◽  
Scott Banta
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
Fluorescent Protein ◽  
Energy Content ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Surface Hydrophobicity ◽  
Substrate Utilization Pattern ◽  
Ferrous Iron Oxidation

Acidithiobacillus ferrooxidans are acidophilic chemolithoautotrophs that are commonly reported to exhibit diauxic population growth behavior where ferrous iron is oxidized before elemental sulfur when both are available, despite the higher energy content of sulfur. We have discovered sulfur dispersion formulations that enables sulfur oxidation before ferrous iron oxidation. The oxidation of dispersed sulfur can lower the culture pH within days below the range where aerobic ferrous iron oxidation can occur so that ferric iron reduction occurs which had previously been reported over extended incubation periods with untreated sulfur. Therefore, we demonstrate that this substrate utilization pattern is strongly dependent on the cell loading in relation to sulfur concentration, sulfur surface hydrophobicity, and the pH of the culture. Our dispersed sulfur formulation, lig-sulfur, can be used to support the rapid antibiotic selection of plasmid-transformed cells, which is not possible in liquid cultures where ferrous iron is the main source of energy for these acidophiles. Furthermore, we find that media containing lig-sulfur supports higher production of green fluorescent protein (GFP) compared to media containing ferrous iron. The use of dispersed sulfur is a valuable new tool for the development of engineered A. ferrooxidans strains and it provides a new method to control iron and sulfur oxidation behaviors.

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