Examinando por Autor "Ulloa, Ricardo"

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    Domestication of local microbial consortia for efficient recovery of gold through top-down selection in airlift bioreactors
    (Frontiers Media S.A., 2019-01) Ulloa, Ricardo; Moya Beltrán, Ana; Rojas Villalobos, Camila; Nuñez, Harold; Chiacchiarini, Patricia; Donati, Edgardo; Giaveno, Alejandra; Quatrini, Raquel
    Extreme acidophiles play central roles in the geochemical cycling of diverse elements in low pH environments. This has been harnessed in biotechnologies such as biomining, where microorganisms facilitate the recovery of economically important metals such as gold. By generating both extreme acidity and a chemical oxidant (ferric iron) many species of prokaryotes that thrive in low pH environments not only catalyze mineral dissolution but also trigger both community and individual level adaptive changes. These changes vary in extent and direction depending on the ore mineralogy, water availability and local climate. The use of indigenous versus introduced microbial consortia in biomining practices is still a matter of debate. Yet, indigenous microbial consortia colonizing sulfidic ores that have been domesticated, i.e., selected for their ability to survive under specific polyextreme conditions, are claimed to outperform un-adapted foreign consortia. Despite this, little is known on the domestication of acidic microbial communities and the changes elicited in their members. In this study, high resolution targeted metagenomic techniques were used to analyze the changes occurring in the community structure of local microbial consortia acclimated to growing under extreme acidic conditions and adapted to endure the conditions imposed by the target mineral during biooxidation of a gold concentrate in an airlift reactor over a period of 2 years. The results indicated that operative conditions evolving through biooxidation of the mineral concentrate exerted strong selective pressures that, early on, purge biodiversity in favor of a few Acidithiobacillus spp. over other iron oxidizing acidophiles. Metagenomic analysis of the domesticated consortium present at the end of the adaptation experiment enabled reconstruction of the RVS1-MAG, a novel representative of Acidithiobacillus ferrooxidans from the Andacollo gold mineral district. Comparative genomic analysis performed with this genome draft revealed a net enrichment of gene functions related to heavy metal transport and stress management that are likely to play a significant role in adaptation and survival to adverse conditions experienced by these acidophiles during growth in presence of gold concentrates. © 2007 - 2019 Frontiers Media S.A. All Rights Reserved.
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    Genomic evolution of the class Acidithiobacillia: deep-branching Proteobacteria living in extreme acidic conditions
    (Springer Nature, 2021-11) Moya-Beltrán, Ana; Beard, Simón; Rojas-Villalobos, Camila; Issotta, Francisco; Gallardo, Yasna; Ulloa, Ricardo; Giaveno, Alejandra; Degli Esposti, Mauro; D. Barrie, Johnson; Quatrini, Raquel
    Members of the genus Acidithiobacillus, now ranked within the class Acidithiobacillia, are model bacteria for the study of chemolithotrophic energy conversion under extreme conditions. Knowledge of the genomic and taxonomic diversity of Acidithiobacillia is still limited. Here, we present a systematic analysis of nearly 100 genomes from the class sampled from a wide range of habitats. Some of these genomes are new and others have been reclassified on the basis of advanced genomic analysis, thus defining 19 Acidithiobacillia lineages ranking at different taxonomic levels. This work provides the most comprehensive classification and pangenomic analysis of this deep-branching class of Proteobacteria to date. The phylogenomic framework obtained illuminates not only the evolutionary past of this lineage, but also the molecular evolution of relevant aerobic respiratory proteins, namely the cytochrome bo3 ubiquinol oxidases. © 2021, The Author(s).
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    Ítem
    Genomic evolution of the class Acidithiobacillia: deep-branching Proteobacteria living in extreme acidic conditions
    (2021-11) Moya-Beltrán, Ana; Beard, Simón; Rojas-Villalobos, Camila; Issotta, Francisco; Gallardo, Yasna; Ulloa, Ricardo; Giaveno, Alejandra; Degli Esposti, Mauro; Johnson, D. Barrios; Quatrini, Raquel
    Members of the genus Acidithiobacillus, now ranked within the class Acidithiobacillia, are model bacteria for the study of chemolithotrophic energy conversion under extreme conditions. Knowledge of the genomic and taxonomic diversity of Acidithiobacillia is still limited. Here, we present a systematic analysis of nearly 100 genomes from the class sampled from a wide range of habitats. Some of these genomes are new and others have been reclassified on the basis of advanced genomic analysis, thus defining 19 Acidithiobacillia lineages ranking at different taxonomic levels. This work provides the most comprehensive classification and pangenomic analysis of this deep-branching class of Proteobacteria to date. The phylogenomic framework obtained illuminates not only the evolutionary past of this lineage, but also the molecular evolution of relevant aerobic respiratory proteins, namely the cytochrome bo3 ubiquinol oxidases.