Comparative genome analysis of Acidithiobacillus ferrooxidans, A. thiooxidans and A. caldus: Insights into their metabolism and ecophysiology

Valdés, Jorge Hernández; Pedroso, Inti; Quatrini, Raquel; Holmes, David S.

doi:10.1016/j.hydromet.2008.05.039

Cited by 84 publications

(64 citation statements)

References 32 publications

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“…In sulfur-oxidizing acidophiles including At. ferrooxidans, these components are proposed to operate together in a pathway known as the 'SQR-system', in which sulfate is an end product (Rohwerder and Sand, 2007;Valdés et al, 2008a;Valdés et al, 2008b). Acidithiobacillus also has components of a partial sox system, including soxAX, soxB and soxYZ, but no evidence for soxCD.…”

Section: Carbon and Energy Metabolisms Of Snottite Populationsmentioning

confidence: 99%

Community genomic analysis of an extremely acidophilic sulfur-oxidizing biofilm

et al. 2011

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Highly acidic (pH 0-1) biofilms, known as 'snottites', form on the walls and ceilings of hydrogen sulfide-rich caves. We investigated the population structure, physiology and biogeochemistry of these biofilms using metagenomics, rRNA methods and lipid geochemistry. Snottites from the Frasassi cave system (Italy) are dominated (470% of cells) by Acidithiobacillus thiooxidans, with smaller populations including an archaeon in the uncultivated 'G-plasma' clade of Thermoplasmatales (415%) and a bacterium in the Acidimicrobiaceae family (45%). Based on metagenomic evidence, the Acidithiobacillus population is autotrophic (ribulose-1,5-bisphosphate carboxylase/ oxygenase (RuBisCO), carboxysomes) and oxidizes sulfur by the sulfide-quinone reductase and sox pathways. No reads matching nitrogen fixation genes were detected in the metagenome, whereas multiple matches to nitrogen assimilation functions are present, consistent with geochemical evidence, that fixed nitrogen is available in the snottite environment to support autotrophic growth. Evidence for adaptations to extreme acidity include Acidithiobacillus sequences for cation transporters and hopanoid synthesis, and direct measurements of hopanoid membrane lipids. Based on combined metagenomic, molecular and geochemical evidence, we suggest that Acidithiobacillus is the snottite architect and main primary producer, and that snottite morphology and distributions in the cave environment are directly related to the supply of C, N and energy substrates from the cave atmosphere.

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Section: Carbon and Energy Metabolisms Of Snottite Populationsmentioning

confidence: 99%

Community genomic analysis of an extremely acidophilic sulfur-oxidizing biofilm

et al. 2011

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“…Genes coding for enzymes involved in the CBB cycle have also been found in the moderate thermophile At. caldus (39). A key enzyme in the CBB cycle is ribulose bisphosphate carboxylase oxygenase (RuBisCO).…”

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confidence: 99%

Production of Glycolic Acid by Chemolithotrophic Iron- and Sulfur-Oxidizing Bacteria and Its Role in Delineating and Sustaining Acidophilic Sulfide Mineral-Oxidizing Consortia

Nancucheo

Johnson

2010

Appl Environ Microbiol

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Glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, Leptospirillum ferriphilum, Acidithiobacillus (At.) ferrooxidans, and At. caldus. Although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (DOC) in cultures of L. ferriphilum but only ca. 5% of the total DOC in cultures of the two Acidithiobacillus spp. Rapid acidification (to pH 1.0) of the culture medium of At. caldus resulted in a large increase in the level of DOC, although the concentration of glycolic acid did not change in proportion. The archaeon Ferroplasma acidiphilum grew in the cell-free spent medium of At. caldus; glycolic acid was not metabolized, although other unidentified compounds in the DOC pool were metabolized. Glycolic acid exhibited levels of toxicity with 21 strains of acidophiles screened similar to those of acetic acid. The most sensitive species were chemolithotrophs (L. ferriphilum and At. ferrivorans), while the most tolerant species were chemoorganotrophs (Acidocella, Acidobacterium, and Ferroplasma species), and the ability to metabolize glycolic acid appeared to be restricted (among acidophiles) to Firmicutes (chiefly Sulfobacillus spp.). Results of this study help explain why Sulfobacillus spp. rather than other acidophiles are the main organic carbon-degrading bacteria in continuously fed stirred tanks used to bioprocess sulfide mineral concentrates and also why temporary cessation of pH control in these systems, resulting in rapid acidification, often results in a plume of the archaeon Ferroplasma.Extremely acidic environments (generally considered environments that have a pH of Ͻ3) are unusual in that chemoautotrophs rather than photoautotrophs are often the dominant (and sometimes exclusive) primary production agents (15). There are two major reasons for this: (i) inorganic electron donors (ferrous iron and reduced forms of sulfur) are often very abundant, as many of the most extremely acidic environments are in sulfur-rich (e.g., solfatara springs) or sulfide mineral-rich (e.g., metal mine wastes) locations, and (ii) in general, cyanobacteria, algae, and higher plants are more sensitive than chemotrophic bacteria and archaea to the elevated concentrations of soluble transition metals and other solutes often present in acidic waters. Lithotrophy-based primary production may be evident in subterranean chambers (caves and worked-out mines) in the form of slimes and massive "acid streamer" growths (2, 22, 30). In lower-temperature (Ͻ40°C) environments, the microorganisms that use energy derived from the oxidation of ferrous iron and/or reduced sulfur to fix CO 2 are predominantly bacteria and include a number of species (e.g., bacteria belonging to the genera Acidithiobacillus and Leptospirillum, as well as the archaeon Ferroplasma) that are known to be fundamentally important in biomining operations (35) and in the generation of ac...

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“…It is well established that multiple genes are involved in the sulfur-metabolic pathways of A. ferrooxidans, among which the tetH gene takes part just in the dissimilation of tetrathionate, an intermediate during sulfur oxidation (4)(5)(6)38). The corresponding reduced and increased growth obtained, respectively, by the ⌬tetH mutant and the tetH overexpression strain when grown in 9K-S 0 medium clearly indicated that TetH influenced the whole metabolism of sulfur to some extent.…”

Section: Discussionmentioning

confidence: 97%

“…Although it was generally considered very difficult to return a certain gene to the extremely acidophilic organism A. ferrooxidans (6,37,38), the tetH gene was successfully introduced into A. ferrooxidans ATCC 23270 by conjugation, and an engineering strain overexpressing the tetH gene under the control of the powerful tac promoter from a broad-host-range plasmid, pMSD1-tac-tetH, was constructed. Therefore, except for the elimination in function by being knocked out, the tetH gene could also be elucidated by its increase in function on account of its overexpression.…”

Section: Discussionmentioning

confidence: 99%

Construction and Characterization of tetH Overexpression and Knockout Strains of Acidithiobacillus ferrooxidans

Liu

Wang

et al. 2014

J Bacteriol

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Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for bioleaching. It can obtain energy from the oxidation of Fe 2؉ , H 2 , S 0 , and various reduced inorganic sulfur compounds (RISCs). Tetrathionate is a key intermediate during RISC oxidation, hydrolyzed by tetrathionate hydrolase (TetH), and used as sole energy source. In this study, a tetH knockout (⌬tetH) mutant and a tetH overexpression strain were constructed and characterized. The tetH overexpression strain grew better on sulfur and tetrathionate and possessed a higher rate of tetrathionate utilization and TetH activity than the wild type. However, its cell yields on tetrathionate were much lower than those on sulfur. The ⌬tetH mutant could not grow on tetrathionate but could proliferate on sulfur with a lower cell yield than the wild type's, which indicated that tetrathionate hydrolysis is mediated only by TetH, encoded by tetH. The ⌬tetH mutant could survive in ferrous medium with an Fe 2؉ oxidation rate similar to that of the wild type. For the tetH overexpression strain, the rate was relatively higher than that of the wild type. The reverse transcription-quantitative PCR (qRT-PCR) results showed that tetH and doxD2 acted synergistically, and doxD2 was considered important in thiosulfate metabolism. Of the two sqr genes, AFE_0267 seemed to play as important a role in sulfide oxidation as AFE_1792. This study not only provides a substantial basis for studying the function of the tetH gene but also may serve as a model to clarify other candidate genes involved in sulfur oxidation in this organism.

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Comparative genome analysis of Acidithiobacillus ferrooxidans, A. thiooxidans and A. caldus: Insights into their metabolism and ecophysiology

Cited by 84 publications

References 32 publications

Community genomic analysis of an extremely acidophilic sulfur-oxidizing biofilm

Community genomic analysis of an extremely acidophilic sulfur-oxidizing biofilm

Production of Glycolic Acid by Chemolithotrophic Iron- and Sulfur-Oxidizing Bacteria and Its Role in Delineating and Sustaining Acidophilic Sulfide Mineral-Oxidizing Consortia

Construction and Characterization of tetH Overexpression and Knockout Strains of Acidithiobacillus ferrooxidans

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