Examinando por Autor "Ossandon, Francisco J."
Mostrando 1 - 7 de 7
Resultados por página
Opciones de ordenación
Ítem Draft genome sequence of chloride-tolerant Leptospirillum ferriphilum Sp-Cl from industrial bioleaching operations in northern Chile(BIOMED CENTRAL, 2016-02) Issotta, Francisco; Galleguillos, Pedro A.; Moya-Beltrán, Ana; Davis-Belmar, Carol S.; Rautenbach, George; Covarrubias, Paulo C.; Acosta, Mauricio; Ossandon, Francisco J.; Contador, Yasna; Holmes, David S.; Marín-Eliantonio, Sabrina; Quatrini, Raquel; Demergasso, CeciliaLeptospirillum ferriphilum Sp-Cl is a Gram negative, thermotolerant, curved, rod- shaped bacterium, isolated from an industrial bioleaching operation in northern Chile, where chalcocite is the major copper mineral and copper hydroxychloride atacamite is present in variable proportions in the ore. This strain has unique features as compared to the other members of the species, namely resistance to elevated concentrations of chloride, sulfate and metals. Basic microbiological features and genomic properties of this biotechnologically relevant strain are described in this work. The 2,475,669 bp draft genome is arranged into 74 scaffolds of 74 contigs. A total of 48 RNA genes and 2,834 protein coding genes were predicted from its annotation; 55 % of these were assigned a putative function. Release of the genome sequence of this strain will provide further understanding of the mechanisms used by acidophilic bacteria to endure high osmotic stress and high chloride levels and of the role of chloride-tolerant iron-oxidizers in industrial bioleaching operations.Ítem Draft genome sequence of the nominated type strain of "Ferrovum myxofaciens," an acidophilic, iron-oxidizing betaproteobacterium(American Society for Microbiology, 2014) Moya-Beltrán, Ana; Cárdenas, Juan Pablo; Covarrubias, Paulo C.; Issotta, Francisco; Ossandon, Francisco J.; Grail, Barry M.; Holmes, David S.; Quatrini, Raquel; Johnson, D. BarrieFerrovum myxofaciens” is an iron-oxidizing betaproteobacterium with widespread distribution in acidic low-temperature en vironments, such as acid mine drainage streams. Here, we describe the genomic features of this novel acidophile and investigate the relevant metabolic pathways that enable its survival in these environments.Ítem Genome analysis of the biotechnologically relevant acidophilic iron oxidising strain JA12 indicates phylogenetic and metabolic diversity within the novel genus "Ferrovum"(Public Library of Science, 2016-01) Ullrich, Sophie R.; Poehlein, Anja; Tischler, Judith S.; González, Carolina; Ossandon, Francisco J.; Daniel, Rolf; Holmes, David S.; Schlömann, Michael; Mühling, MartinBackground: Members of the genus "Ferrovum" are ubiquitously distributed in acid mine drainage (AMD) waters which are characterised by their high metal and sulfate loads. So far isolation and microbiological characterisation have only been successful for the designated type strain "Ferrovum myxofaciens" P3G. Thus, knowledge about physiological characteristics and the phylogeny of the genus "Ferrovum" is extremely scarce. Objective: In order to access the wider genetic pool of the genus "Ferrovum" we sequenced the genome of a "Ferrovum"-containing mixed culture and successfully assembled the almost complete genome sequence of the novel "Ferrovum" strain JA12. Phylogeny and lifestyle: The genome-based phylogenetic analysis indicates that strain JA12 and the type strain represent two distinct "Ferrovum" species. "Ferrovum" strain JA12 is characterised by an unusually small genome in comparison to the type strain and other iron oxidising bacteria. The prediction of nutrient assimilation pathways suggests that "Ferrovum" strain JA12 maintains a chemolithoautotrophic lifestyle utilising carbon dioxide and bicarbonate, ammonium and urea, sulfate, phosphate and ferrous iron as carbon, nitrogen, sulfur, phosphorous and energy sources, respectively. Unique Metabolic Features: The potential utilisation of urea by "Ferrovum" strain JA12 is moreover remarkable since it may furthermore represent a strategy among extreme acidophiles to cope with the acidic environment. Unlike other acidophilic chemolithoautotrophs "Ferrovum" strain JA12 exhibits a complete tricarboxylic acid cycle, a metabolic feature shared with the closer related neutrophilic iron oxidisers among the Betaproteobacteria including Sideroxydans lithotrophicus and Thiobacillus denitrificans. Furthermore, the absence of characteristic redox proteins involved in iron oxidation in the well-studied acidophiles Acidithiobacillus ferrooxidans (rusticyanin) and Acidithiobacillus ferrivorans (iron oxidase) indicates the existence of a modified pathway in "Ferrovum" strain JA12. Therefore, the results of the present study extend our understanding of the genus "Ferrovum" and provide a comprehensive framework for future comparative genome and metagenome studies. © 2016 Ullrich et al.Ítem Metagenomic analysis reveals adaptations to a cold-adapted lifestyle in a low-temperature acid mine drainage stream(Oxford University Press, 2015-04) Liljeqvist, Maria; Ossandon, Francisco J.; González, Carolina; Rajan, Sukithar; Stell, Adam; Valdes, Jorge; Holmes, David S.; Dopson, MarkAn acid mine drainage (pH 2.5-2.7) stream biofilm situated 250 m below ground in the low-temperature (6-10°C)Kristineberg mine, northern Sweden, contained a microbial community equipped for growth at low temperature and acidicpH. Metagenomic sequencing of the biofilm and planktonic fractions identified the most abundant microorganism to besimilar to the psychrotolerant acidophile, Acidithiobacillus ferrivorans. In addition, metagenome contigs were most similar toother Acidithiobacillus species, an Acidobacteria-like species, and a Gallionellaceae-like species. Analyses of the metagenomesindicated functional characteristics previously characterized as related to growth at low temperature including cold-shockproteins, several pathways for the production of compatible solutes and an anti-freeze protein. In addition, genes werepredicted to encode functions related to pH homeostasis and metal resistance related to growth in the acidicmetal-containing mine water. Metagenome analyses identified microorganisms capable of nitrogen fixation and exhibitinga primarily autotrophic lifestyle driven by the oxidation of the ferrous iron and inorganic sulfur compounds contained in thesulfidic mine waters. The study identified a low diversity of abundant microorganisms adapted to a low-temperature acidicenvironment as well as identifying some of the strategies the microorganisms employ to grow in this extreme environment. © FEMS 2015.Ítem Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms(Frontiers Media S.A., 2014-04) Dopson, Mark; Ossandon, Francisco J.; Lövgren, Lars; Holmes, David S.All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account. © 2014 Dopson, Ossandon, Laóvgren and Holmes.Ítem Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms(Frontiers Media S.A., 2014-04) Dopson, Mark; Ossandon, Francisco J.; Lövgren, Lars; Holmes, David S.All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account. © 2014 Dopson, Ossandon, Laóvgren and Holmes.Ítem Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms(Frontiers Research Foundation, 2014-04) Dopson, Mark; Ossandon, Francisco J.; Lövgren, Lars; Holmes, David S.All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account. © 2014 Dopson, Ossandon, Laóvgren and Holmes.