Examinando por Autor "Pedroso, Inti"

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    Acidithiobacillus ferrooxidans metabolism: From genome sequence to industrial applications
    (BMC, 2008-12-11) Valdés, Jorge; Pedroso, Inti; Quatrini, Raquel; Dodson, Robert J.; Tettelin, Herve; Blake II, Robert; Eisen, Jonathan A.; Holmes, David S.
    Background: Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for the industrial recovery of copper (bioleaching or biomining). It is a chemolithoautrophic, γ-proteobacterium using energy from the oxidation of iron- and sulfur-containing minerals for growth. It thrives at extremely low pH (pH 1-2) and fixes both carbon and nitrogen from the atmosphere. It solubilizes copper and other metals from rocks and plays an important role in nutrient and metal biogeochemical cycling in acid environments. The lack of a well-developed system for genetic manipulation has prevented thorough exploration of its physiology. Also, confusion has been caused by prior metabolic models constructed based upon the examination of multiple, and sometimes distantly related, strains of the microorganism. Results: The genome of the type strain A. ferrooxidans ATCC 23270 was sequenced and annotated to identify general features and provide a framework for in silico metabolic reconstruction. Earlier models of iron and sulfur oxidation, biofilm formation, quorum sensing, inorganic ion uptake, and amino acid metabolism are confirmed and extended. Initial models are presented for central carbon metabolism, anaerobic metabolism (including sulfur reduction, hydrogen metabolism and nitrogen fixation), stress responses, DNA repair, and metal and toxic compound fluxes. Conclusion: Bioinformatics analysis provides a valuable platform for gene discovery and functional prediction that helps explain the activity of A. ferrooxidans in industrial bioleaching and its role as a primary producer in acidic environments. An analysis of the genome of the type strain provides a coherent view of its gene content and metabolic potential. © 2008 Valdés et al; licensee BioMed Central Ltd.
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    AlterORF: A database of alternate open reading frames
    (Oxford University Press, 2008-01) Pedroso, Inti; Rivera, Gustavo; Lazo, Felipe; Chacón, Max; Ossandón, Francisco; Veloso, Felipe A.; Holmes, David S.
    AlterORF is a searchable database that contains information regarding alternate open reading frames (ORFs) for over 1.5 million genes in 481 prokaryotic genomes. The objective of the database is to provide a platform for improving genome annotation and to serve as an aid for the identification of prokaryotic genes that potentially encode proteins in more than one reading frame. The AlterORF Database can be accessed through a web interface at www.alterorf.cl. © 2007 The Author(s).
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    Bioinformatic prediction and experimental verification of Fur-regulated genes in the extreme acidophile Acidithiobacillus ferrooxidans
    (2007-04) Quatrini, Raquel; Lefimil, Claudia; Veloso, Felipe A.; Pedroso, Inti; Holmes, David S.; Jedlicki, Eugenia
    The γ-proteobacterium Acidithiobacillus ferrooxidans lives in extremely acidic conditions (pH 2) and, unlike most organisms, is confronted with an abundant supply of soluble iron. It is also unusual in that it oxidizes iron as an energy source. Consequently, it faces the challenging dual problems of (i) maintaining intracellular iron homeostasis when confronted with extremely high environmental loads of iron and (ii) of regulating the use of iron both as an energy source and as a metabolic micronutrient. A combined bioinformatic and experimental approach was undertaken to identify Fur regulatory sites in the genome of A. ferrooxidans and to gain insight into the constitution of its Fur regulon. Fur regulatory targets associated with a variety of cellular functions including metal trafficking (e.g. feoPABC, tdr, tonBexbBD, copB, cdf), utilization (e.g. fdx, nif, transcriptional regulation (e.g. phoB, irr, iscR) and redox balance (grx), trx, gst) were identified. Selected predicted Fur regulatory sites were confirmed by FURTA, EMSA and in vitro transcription analyses. This study provides the first model for a Fur-binding site consensus sequence in an acidophilic iron-oxidizing microorganism and lays the foundation for future studies aimed at deepening our understanding of the regulatory networks that control iron uptake, homeostasis and oxidation in extreme acidophiles. © 2007 The Author(s).