Acidithiobacillus ferrooxidans metabolism: from genome sequence to industrial applications

<p>Abstract</p> <p>Background</p> <p><it>Acidithiobacillus ferrooxidans </it>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.</p> <p>Results</p> <p>The genome of the type strain <it>A. ferrooxidans </it>ATCC 23270 was sequenced and annotated to identify general features and provide a framework for <it>in silico </it>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.</p> <p>Conclusion</p> <p>Bioinformatics analysis provides a valuable platform for gene discovery and functional prediction that helps explain the activity of <it>A. ferrooxidans </it>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.</p

Evaluación de la reactividad de un antígeno purificado de

Se evaluó la reactividad de un antígeno metabolico « crudo » y de un extracto metabolico « purificado » de P. brasiliensis, mediante inmunoelectroforesis, frente a 10 sueros de paracoccidioidomicosis y 6 de histoplasmosis. Ambos antígenos dieron origen al sistema precipitante especifico en 9 de los 10 sueros de paracoccidioidomicosis. El antígeno « crudo » reveló anticuerpos precipitantes en todas las muestras estudiadas, aunque el numero de arcos formados fue mayor en los inmunosueros homólogos. El antígeno « purificado », por el contrario, solo reaccionó con los sueros de paracoccidioidomicosis. Se postula que el uso del antígeno « purificado » puede reducir significativamente el riesgo de inespecificidad en pruebas como la doble difusión en gel, que presentan reacciones cruzadas con sueros de otras micosis, especialmente con la histoplasmosis