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Author (up) Cortes, M.P.; Mendoza, S.N.; Travisany, D.; Gaete, A.; Siegel, A.; Cambiazo, V.; Maass, A.
Title Analysis of Piscirickettsia salmonis Metabolism Using Genome-Scale Reconstruction, Modeling, and Testing Type
Year 2017 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 8 Issue Pages 15 pp
Keywords pathogen; genome-scale; metabolism; constraint-based; Piscirickettsia; salmonis
Abstract Piscirickettsia salmonis is an intracellular bacterial fish pathogen that causes piscirickettsiosis, a disease with highly adverse impact in the Chilean salmon farming industry. The development of effective treatment and control methods for piscireckttsiosis is still a challenge. To meet it the number of studies on P. salmonis has grown in the last couple of years but many aspects of the pathogen's biology are still poorly understood. Studies on its metabolism are scarce and only recently a metabolic model for reference strain LF-89 was developed. We present a new genomescale model for P. salmonis LF-89 with more than twice as many genes as in the previous model and incorporating specific elements of the fish pathogen metabolism. Comparative analysis with models of different bacterial pathogens revealed a lower flexibility in P. salmonis metabolic network. Through constraint-based analysis, we determined essential metabolites required for its growth and showed that it can benefit from different carbon sources tested experimentally in new defined media. We also built an additional model for strain A1-15972, and together with an analysis of P. salmonis pangenome, we identified metabolic features that differentiate two main species clades. Both models constitute a knowledge-base for P. salmonis metabolism and can be used to guide the efficient culture of the pathogen and the identification of specific drug targets.
Address [Cortes, Maria P.; Mendoza, Sebastian N.; Travisany, Dante; Maass, Alejandro] Univ Chile, Ctr Math Modeling, Math, Santiago, Chile, Email: mpcortes@dim.uchile.cl
Corporate Author Thesis
Publisher Frontiers Media Sa Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302x ISBN Medium
Area Expedition Conference
Notes WOS:000417578100001 Approved
Call Number UAI @ eduardo.moreno @ Serial 787
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Author (up) Diaz-Rullo, J.; Rodriguez-Valdecantos, G.; Torres-Rojas, F.; Cid, L.; Vargas, I.T.; Gonzalez, B.; Gonzalez-Pastor, J.E.
Title Mining for Perchlorate Resistance Genes in Microorganisms From Sediments of a Hypersaline Pond in Atacama Desert, Chile Type
Year 2021 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 12 Issue Pages 723874
Keywords perchlorate-resistance; oxidative stress; tRNA modification; DNA repair; protein damage; hypersaline environments; Atacama Desert; Mars
Abstract Perchlorate is an oxidative pollutant toxic to most of terrestrial life by promoting denaturation of macromolecules, oxidative stress, and DNA damage. However, several microorganisms, especially hyperhalophiles, are able to tolerate high levels of this compound. Furthermore, relatively high quantities of perchlorate salts were detected on the Martian surface, and due to its strong hygroscopicity and its ability to substantially decrease the freezing point of water, perchlorate is thought to increase the availability of liquid brine water in hyper-arid and cold environments, such as the Martian regolith. Therefore, perchlorate has been proposed as a compound worth studying to better understanding the habitability of the Martian surface. In the present work, to study the molecular mechanisms of perchlorate resistance, a functional metagenomic approach was used, and for that, a small-insert library was constructed with DNA isolated from microorganisms exposed to perchlorate in sediments of a hypersaline pond in the Atacama Desert, Chile (Salar de Maricunga), one of the regions with the highest levels of perchlorate on Earth. The metagenomic library was hosted in Escherichia coli DH10B strain and exposed to sodium perchlorate. This technique allowed the identification of nine perchlorate-resistant clones and their environmental DNA fragments were sequenced. A total of seventeen ORFs were predicted, individually cloned, and nine of them increased perchlorate resistance when expressed in E. coli DH10B cells. These genes encoded hypothetical conserved proteins of unknown functions and proteins similar to other not previously reported to be involved in perchlorate resistance that were related to different cellular processes such as RNA processing, tRNA modification, DNA protection and repair, metabolism, and protein degradation. Furthermore, these genes also conferred resistance to UV-radiation, 4-nitroquinoline-N-oxide (4-NQO) and/or hydrogen peroxide (H2O2), other stress conditions that induce oxidative stress, and damage in proteins and nucleic acids. Therefore, the novel genes identified will help us to better understand the molecular strategies of microorganisms to survive in the presence of perchlorate and may be used in Mars exploration for creating perchlorate-resistance strains interesting for developing Bioregenerative Life Support Systems (BLSS) based on in situ resource utilization (ISRU).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302X ISBN Medium
Area Expedition Conference
Notes WOS:000681631900001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1456
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Author (up) Heuer, H.; Binh, C.T.T.; Jechalke, S.; Kopmann, C.; Zimmerling, U.; Krogerrecklenfort, E.; Ledger, T.; Gonzalez, B.; Top, E.; Smalla, K.
Title IncP-1 epsilon plasmids are important vectors of antibiotic resistance genes in agricultural systems: diversification driven by class 1 integron gene cassettes Type
Year 2012 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 3 Issue Pages 8 pp
Keywords IncP-1 epsilon plasmid; exogenous isolation; complete sequence; gene cassette; qPCR; arable soil; pig manure
Abstract The role of broad-host range IncP-1 epsilon plasmids in the dissemination of antibiotic resistance in agricultural systems has not yet been investigated. These plasmids were detected in total DNA from all of 16 manure samples and in arable soil based on a novel 5'-nuclease assay for real-time PCR. A correlation between IncP-1 epsilon plasmid abundance and antibiotic usage was revealed. In a soil microcosm experiment the abundance of IncP-1 epsilon plasmids was significantly increased even 127 days after application of manure containing the antibiotic compound sulfadiazine, compared to soil receiving only manure, only sulfadiazine, or water. Fifty IncP-1 epsilon plasmids that were captured in E. coli CV601gfp from bacterial communities of manure and arable soil were characterized by PCR and hybridization. All plasmids carried class 1 integrons with highly varying sizes of the gene cassette region and the sul1 gene. Three IncP-1 epsilon plasmids captured from soil bacteria and one from manure were completely sequenced. The backbones were nearly identical to that of the previously described IncP-1 epsilon plasmid pKJK5. The plasmids differed mainly in the composition of a Tn402-like transposon carrying a class 1 integron with varying gene cassettes, IS 1326, and in three of the plasmids the tetracycline resistance transposon In 1721 with various truncations. Diverse Beta- and Gammaproteobacteria were revealed as hosts of one of the IncP-1 epsilon plasmids in soil microcosms. Our data suggest that IncP-1 epsilon plasmids are important vectors for horizontal transfer of antibiotic resistance in agricultural systems.
Address [Heuer, Holger; Binh, Chu T. T.; Jechalke, Sven; Kopmann, Christoph; Zimmerling, Ute; Kroegerrecklenfort, Ellen; Smalla, Kornelia] Julius Kuhn Inst, Inst Epidemiol & Pathogen Diagnost, Fed Res Ctr Cultivated Plants, D-38104 Braunschweig, Germany, Email: kornelia.smalla@jki.bund.de
Corporate Author Thesis
Publisher Frontiers Research Foundation Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302x ISBN Medium
Area Expedition Conference
Notes WOS:000208863600056 Approved
Call Number UAI @ eduardo.moreno @ Serial 467
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Author (up) Ledger, T.; Rojas, S.; Timmermann, T.; Pinedo, I.; Poupin, M.J.; Garrido, T.; Richter, P.; Tamayo, J.; Donoso, R.
Title Volatile-Mediated Effects Predominate in Paraburkholderia phytofirmans Growth Promotion and Salt Stress Tolerance of Arabidopsis thaliana Type
Year 2016 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 7 Issue Pages 18 pp
Keywords plant growth promoting rhizobacteria (PGPR); Paraburkholderia phytofirmans PsJN; Arabidopsis thaliana; abiotic stress tolerance; ACC deaminase; volatile organic compounds (VOCs)
Abstract Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity. This work investigated bacterial determinants involved in PsJN stimulation of growth and salinity tolerance in Arabidopsis thaliana, showing bacteria enable plants to survive long-term salinity treatment, accumulating less sodium within leaf tissues relative to non-inoculated controls. Inactivation of specific bacterial genes encoding ACC deaminase, auxin catabolism, N-acyl-homosenne-lactone production, and flagellin synthesis showed these functions have little influence on bacterial induction of salinity tolerance. Volatile organic compound emission from strain PsJN was shown to reproduce the effects of direct bacterial inoculation of roots, increasing plant growth rate and tolerance to salinity evaluated both in vitro and in soil. Furthermore, early exposure to VOCs from P phytofirmans was sufficient to stimulate long-term effects observed in Arabidopsis growth in the presence and absence of salinity. Organic compounds were analyzed in the headspace of PsJN cultures, showing production of 2-undecanone, 7-hexanol, 3-methylbutanol and dimethyl disulfide. Exposure of A. thaliana to different quantities of these molecules showed that they are able to influence growth in a wide range of added amounts. Exposure to a blend of the first three compounds was found to mimic the effects of PsJN on both general growth promotion and salinity tolerance. To our knowledge, this is the first report on volatile compound-mediated induction of plant abiotic stress tolerance by a Paraburkholderia species.
Address [Ledger, Thomas; Rojas, Sandy; Timmermann, Tania; Pinedo, Ignacio; Poupin, Maria J.; Tamayo, Javier; Donoso, Raul] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Lab Bioingn, Santiago, Chile, Email: tledger@uai.cl
Corporate Author Thesis
Publisher Frontiers Media Sa Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302x ISBN Medium
Area Expedition Conference
Notes WOS:000388754700001 Approved
Call Number UAI @ eduardo.moreno @ Serial 679
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Author (up) Plominsky, A.M.; Henriquez-Castillo, C.; Delherbe, N.; Podell, S.; Ramirez-Flandes, S.; Ugalde, J.A.; Santibanez, J.F.; van den Engh, G.; Hanselmann, K.; Ulloa, O.; De la Iglesia, R.; Allen, E.E.; Trefault, N.
Title Distinctive Archaeal Composition of an Artisanal Crystallizer Pond and Functional Insights Into Salt-Saturated Hypersaline Environment Adaptation Type
Year 2018 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 9 Issue Pages 13 pp
Keywords hypersaline environments; solar salterns; metagenomics; microbial ecology; environmental adaptation; functional metagenomics; artisanal crystallizer pond
Abstract Hypersaline environments represent some of the most challenging settings for life on Earth. Extremely halophilic microorganisms have been selected to colonize and thrive in these extreme environments by virtue of a broad spectrum of adaptations to counter high salinity and osmotic stress. Although there is substantial data on microbial taxonomic diversity in these challenging ecosystems and their primary osmoadaptation mechanisms, less is known about how hypersaline environments shape the genomes of microbial inhabitants at the functional level. In this study, we analyzed the microbial communities in five ponds along the discontinuous salinity gradient from brackish to salt-saturated environments and sequenced the metagenome of the salt (halite) precipitation pond in the artisanal Cahuil Solar Saltern system. We combined field measurements with spectrophotometric pigment analysis and flow cytometry to characterize the microbial ecology of the pond ecosystems, including primary producers and applied metagenomic sequencing for analysis of archaeal and bacterial taxonomic diversity of the salt crystallizer harvest pond. Comparative metagenomic analysis of the Cahuil salt crystallizer pond against microbial communities from other salt-saturated aquatic environments revealed a dominance of the archaeal genus Halorubrum and showed an unexpectedly low abundance of Haloquadratum in the Cahuil system. Functional comparison of 26 hypersaline microbial metagenomes revealed a high proportion of sequences associated with nucleotide excision repair, helicases, replication and restriction-methylation systems in all of them. Moreover, we found distinctive functional signatures between the microbial communities from salt-saturated (>30% [w/v] total salinity) compared to sub-saturated hypersaline environments mainly due to a higher representation of sequences related to replication, recombination and DNA repair in the former. The current study expands our understanding of the diversity and distribution of halophilic microbial populations inhabiting salt-saturated habitats and the functional attributes that sustain them.
Address [Plominsky, Alvaro M.; Henriquez-Castillo, Carlos; Santibanez, Juan F.; Ulloa, Osvaldo] Univ Concepcion, Fac Nat & Oceanog Sci, Dept Oceanog, Concepcion, Chile, Email: eallen@ucsd.edu;
Corporate Author Thesis
Publisher Frontiers Media Sa Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302x ISBN Medium
Area Expedition Conference
Notes WOS:000441537100001 Approved
Call Number UAI @ eduardo.moreno @ Serial 895
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Author (up) Tapia, J.E.; Gonzalez, B.; Goulitquer, S.; Potin, P.; Correa, J.A.
Title Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp Type
Year 2016 Publication Frontiers In Microbiology Abbreviated Journal Front. Microbiol.
Volume 7 Issue Pages 14 pp
Keywords microbiota; bacteria-algae interaction; Ectocarpus; bacterial isolate; algal morphology; exometabolome
Abstract Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga.
Address [Tapia, Javier E.; Correa, Juan A.] Univ Paris 06, CNRS, Biol & Ecol Algae, Stn Biol Roscoff, Roscoff, France, Email: jcorrea@bio.puc.cl
Corporate Author Thesis
Publisher Frontiers Media Sa Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-302x ISBN Medium
Area Expedition Conference
Notes WOS:000370760000001 Approved
Call Number UAI @ eduardo.moreno @ Serial 589
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