Regulation of the Iron and Sulfur Oxidation Pathways in the Acidophilic Acidithiobacillus Ferrooxidans

2009 ◽  
Vol 71-73 ◽  
pp. 163-166 ◽  
Author(s):  
A. Amouric ◽  
C. Appia-Ayme ◽  
A. Yarzabal ◽  
Violaine Bonnefoy
Keyword(s):  
Recombinant Proteins ◽  
Acidithiobacillus Ferrooxidans ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Transcriptional Unit ◽  
Two Component ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Transcriptional Units ◽  
Iron And Sulfur Oxidation

The acidophilic and strictly chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans oxidizes ferrous (Fe(II)) to ferric (Fe(III)) iron and reduced inorganic sulfur compounds (RISC) to sulfuric acid, in oxic conditions. The redox proteins involved in the electron transfer between Fe(II) and oxygen are encoded in the same transcriptional unit, the rus operon. The expression of this operon is induced in the presence of Fe(II), but not Fe(III), and is not repressed in the presence of sulfur (S0). A number of genes differentially expressed in iron or sulfur conditions have been identified by microarrays transcript profiling. We show here that the presence of Fe(II) induced the expression of the genes involved in iron oxidation and repressed the expression of the genes involved in RISC oxidation. Identification of the regulator(s) involved in this transcriptional regulation is underway. Two genes encoding putative regulators belonging to two transcriptional units located downstream from the rus operon have been cloned. One regulator with a putative ironsulfur cluster belongs to the IscR family and the other belongs to the two component sensor/regulator family. Expression of both genes is induced in the presence of Fe(II) and is not repressed by S0. The recombinant proteins have been purified and gel shift assays with the target regulatory regions are in progress.

How the RegBA Redox Responding System Controls Iron and Sulfur Oxidation in Acidithiobacillus ferrooxidans

2013 ◽  
Vol 825 ◽  
pp. 186-189 ◽  
Author(s):  
Danielle Moinier ◽  
Deborah Byrne ◽  
Agnès Amouric ◽  
Violaine Bonnefoy
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Iron Oxidation ◽  
Regulatory Region ◽  
Sulfur Oxidation ◽  
Sulfur Compounds ◽  
Chemical Attack ◽  
Valuable Metals ◽  
Genes Encoding ◽  
Iron And Sulfur Oxidation

Valuable metals as well as ferrous iron and sulfur compounds are released from ore by ferric iron and sulfuric acid chemical attack. Biomining microorganisms allow the recycling of these products by oxidizing ferrous iron and/or sulfur compounds. The energy released from the oxidation of these substrates is used for the growth of the acidophilic chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans. The respiratory pathways involved in these respiratory processes have been deciphered and the expression of the genes encoding these redox proteins is dependent on the electron donor present in the medium. Furthermore, in the presence of both ferrous iron and sulfur, the genes involved in iron oxidation are expressed before those involved in sulfur oxidation. We propose that the global redox responding two component system RegBA is responsible for this regulation since (i) the redox potential increases during iron oxidation but remains stable during sulfur oxidation and (ii) the transcriptional regulator RegA binds the regulatory region of a number of genes/operons involved in iron and sulfur oxidation. To understand the mechanism of the At. ferrooxidans RegBA system, the regA gene and the DNA corresponding to the DNA binding domain of RegA were cloned in an expression plasmid in Escherichia coli. The recombinant proteins, RegA and RegA-HTH respectively, were purified. The binding of RegA-HTH, phosphorylated and unphosphorylated RegA on the regulatory region of some target operons have been compared by gel shift mobility assay.

Iron and sulfur oxidation pathways of Acidithiobacillus ferrooxidans

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Yue Zhan ◽  
Mengran Yang ◽  
Shuang Zhang ◽  
Dan Zhao ◽  
Jiangong Duan ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Sulfur Oxidation ◽  
Iron And Sulfur Oxidation

scholarly journals Two-Component Systems in the Regulation of Sulfur and Ferrous Iron Oxidation in Acidophilic Bacteria

2021 ◽  
Author(s):  
Lifeng Li ◽  
Zhaobao Wang
Keyword(s):  
Ferrous Iron ◽  
Response Regulator ◽  
Iron Oxidation ◽  
Regulatory System ◽  
Sulfur Oxidation ◽  
Acidophilic Bacteria ◽  
Ferrous Iron Oxidation ◽  
Two Component ◽  
Two Component Systems ◽  
External Stimuli

The two-component system (TCS) is a regulatory system composed of a sensor histidine kinase (HK) and a cytoplasmic response regulator (RR), which participates in the bacterial adaptation to external stimuli. Sulfur oxidation and ferrous iron oxidation are basic energy metabolism systems for chemoautotrophic acidophilic bacteria in acid mine environments. Understanding how these bacteria perceive and respond to complex environmental stimuli offers insights into oxidization mechanisms and the potential for improved applications. In this chapter, we summarized the TCSs involved in the regulation of sulfur and ferrous iron metabolic pathways in these acidophilic bacteria. In particular, we examined the role and molecular mechanism of these TCSs in the regulation of iron and sulfur oxidation in Acidithiobacillus spp.. Moreover, research perspectives on TCSs in acidophilic bacteria are discussed in this section.

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.

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 Extending the models for iron and sulfur oxidation in the extreme Acidophile Acidithiobacillus ferrooxidans

BMC Genomics ◽  
2009 ◽  
Vol 10 (1) ◽  
pp. 394 ◽  
Author(s):  
Raquel Quatrini ◽  
Corinne Appia-Ayme ◽  
Yann Denis ◽  
Eugenia Jedlicki ◽  
David S Holmes ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Sulfur Oxidation ◽  
Iron And Sulfur Oxidation

Biological iron oxidation-reduction and the effects on sulfur oxidation-reduction, denitrification and poly-P accumulation in an anaerobic-oxic activated sludge

2002 ◽  
Vol 46 (1-2) ◽  
pp. 55-60 ◽  
Author(s):  
R. Yamamoto-Ikemoto ◽  
T. Komori ◽  
S. Matsui
Keyword(s):  
Activated Sludge ◽  
Sulfate Reduction ◽  
Iron Reduction ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Monod Equation ◽  
Oxidation Rates ◽  
Oxidation Reduction ◽  
Initial Iron ◽  
P Accumulation

Iron oxidation and reduction were examined using the activated sludge from a municipal plant. Iron contents of the activated sludge were 1–2%. Iron oxidation rates were correlated with the initial iron concentrations. Iron reducing rates could be described by the Monod equation. The effects of iron reducing bacteria on sulfate reduction, denitrification and poly-P accumulation were examined. Iron reduction suppressed sulfate reduction by competing with hydrogen produced from protein. Denitrification was outcompeted with iron reduction and sulfate reduction. These phenomena could be explained thermodynamically. Poly-P accumulation was also suppressed by denitrification. The activity of iron reduction was relatively high.

scholarly journals Ectopic expression of the Stabilin2 gene triggered by an intracisternal A particle (IAP) element in DBA/2J strain of mice

2020 ◽  
Vol 31 (1-2) ◽  
pp. 2-16 ◽  
Author(s):  
Nobuyo Maeda-Smithies ◽  
Sylvia Hiller ◽  
Sharlene Dong ◽  
Hyung-Suk Kim ◽  
Brian J. Bennett ◽  
...  
Keyword(s):  
Promoter Region ◽  
Transmembrane Protein ◽  
Scavenger Receptor ◽  
Ectopic Expression ◽  
Complete Suppression ◽  
Liver Sinusoidal Endothelial Cells ◽  
Normal Expression ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Intracisternal A Particle

AbstractStabilin2 (Stab2) encodes a large transmembrane protein which is predominantly expressed in the liver sinusoidal endothelial cells (LSECs) and functions as a scavenger receptor for various macromolecules including hyaluronans (HA). In DBA/2J mice, plasma HA concentration is ten times higher than in 129S6 or C57BL/6J mice, and this phenotype is genetically linked to the Stab2 locus. Stab2 mRNA in the LSECs was significantly lower in DBA/2J than in 129S6, leading to reduced STAB2 proteins in the DBA/2J LSECs. We found a retrovirus-derived transposable element, intracisternal A particle (IAP), in the promoter region of Stab2DBA which likely interferes with normal expression in the LSECs. In contrast, in other tissues of DBA/2J mice, the IAP drives high ectopic Stab2DBA transcription starting within the 5′ long terminal repeat of IAP in a reverse orientation and continuing through the downstream Stab2DBA. Ectopic transcription requires the Stab2-IAP element but is dominantly suppressed by the presence of loci on 59.7–73.0 Mb of chromosome (Chr) 13 from C57BL/6J, while the same region in 129S6 requires additional loci for complete suppression. Chr13:59.9–73 Mb contains a large number of genes encoding Krüppel-associated box-domain zinc-finger proteins that target transposable elements-derived sequences and repress their expression. Despite the high amount of ectopic Stab2DBA transcript in tissues other than liver, STAB2 protein was undetectable and unlikely to contribute to the plasma HA levels of DBA/2J mice. Nevertheless, the IAP insertion and its effects on the transcription of the downstream Stab2DBA exemplify that stochastic evolutional events could significantly influence susceptibility to complex but common diseases.

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