Browsing by Author "Castro, Matias"

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    Acidithiobacillia class members originating at sites within the Pacific Ring of Fire and other tectonically active locations and description of the novel genus 'Igneacidithiobacillus'
    (2024) Arisan, Dilanaz; Moya-Beltran, Ana; Rojas-Villalobos, Camila; Issotta, Francisco; Castro, Matias; Ulloa, Ricardo; Chiacchiarini, Patricia A.; Diez, Beatriz; Martin, Alberto J. M.; Nancucheo, Ivan; Giaveno, Alejandra; Johnson, D. Barrie; Quatrini, Raquel
    Recent studies have expanded the genomic contours of the Acidithiobacillia, highlighting important lacunae in our comprehension of the phylogenetic space occupied by certain lineages of the class. One such lineage is 'Igneacidithiobacillus', a novel genus-level taxon, represented by 'Igneacidithiobacillus copahuensis' VAN18-1(T) as its type species, along with two other uncultivated metagenome-assembled genomes (MAGs) originating from geothermally active sites across the Pacific Ring of Fire. In this study, we investigate the genetic and genomic diversity, and the distribution patterns of several uncharacterized Acidithiobacillia class strains and sequence clones, which are ascribed to the same 16S rRNA gene sequence clade. By digging deeper into this data and contributing to novel MAGs emerging from environmental studies in tectonically active locations, the description of this novel genus has been consolidated. Using state-of-the-art genomic taxonomy methods, we added to already recognized taxa, an additional four novel Candidate (Ca.) species, including 'Ca. Igneacidithiobacillus chanchocoensis' (mCHCt20-1(TS)), 'Igneacidithiobacillus siniensis' (S30A2(T)), 'Ca. Igneacidithiobacillus taupoensis' (TVZ-G3 (TS)), and 'Ca. Igneacidithiobacillus waiarikiensis' (TVZ-G4 (TS)). Analysis of published data on the isolation, enrichment, cultivation, and preliminary microbiological characterization of several of these unassigned or misassigned strains, along with the type species of the genus, plus the recoverable environmental data from metagenomic studies, allowed us to identify habitat preferences of these taxa. Commonalities and lineage-specific adaptations of the seven species of the genus were derived from pangenome analysis and comparative genomic metabolic reconstruction. The findings emerging from this study lay the groundwork for further research on the ecology, evolution, and biotechnological potential of the novel genus 'Igneacidithiobacillus'.
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    Membrane vesicles in Acidithiobacillia class extreme acidophiles: influence on collective behaviors of 'Fervidacidithiobacillus caldus'
    (2024) Rossoni, Stefano; Beard, Simon; Segura-Bidermann, Maria Ignacia; Duarte-Ramirez, Juan; Osorio, Francisco Kirhman; Varas-Godoy, Manuel; Martinez-Bellange, Patricio; Vera, Mario; Quatrini, Raquel; Castro, Matias
    Membrane vesicles (MVs) are envelope-derived extracellular sacs that perform a broad diversity of physiological functions in bacteria. While considerably studied in pathogenic microorganisms, the roles, relevance, and biotechnological potential of MVs from environmental bacteria are less well established. Acidithiobacillaceae family bacteria are active players in the sulfur and iron biogeochemical cycles in extremely acidic environments and drivers of the leaching of mineral ores contributing to acid rock/mine drainage (ARD/AMD) and industrial bioleaching. One key aspect of such a role is the ability of these bacteria to tightly interact with the mineral surfaces and extract electrons and nutrients to support their chemolithotrophic metabolism. Despite recent advances in the characterization of acidithiobacilli biofilms and extracellular matrix (ECM) components, our understanding of its architectural and mechanistic aspects remains scant. Using different microscopy techniques and nano-tracking analysis we show that vesiculation is a common phenomenon in distant members of the Acidithiobacillaceae family, and further explore the role of MVs in multicellular colonization behaviors using 'Fervidacidithiobacillus caldus' as a bacterial model. Production of MVs in 'F. caldus' occurred in both planktonic cultures and biofilms formed on sulfur surfaces, where MVs appeared individually or in chains resembling tube-shaped membranous structures (TSMSs) important for microbial communication. Liquid chromatography-mass spectrometry data and bioinformatic analysis of the MV-associated proteome revealed that 'F. caldus' MVs were enriched in proteins involved in cell-cell and cell-surface processes and largely typified the MVs as outer MVs (OMVs). Finally, microbiological assays showed that amendment of 'F. caldus' MVs to cells and/or biofilms affects collective colonizing behaviors relevant to the ecophysiology and applications of these acidophiles, providing grounds for their exploitation in biomining.
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    Quorum Sensing Signaling Molecules Positively Regulate c-di-GMP Effector PelD Encoding Gene and PEL Exopolysaccharide Biosynthesis in Extremophile Bacterium Acidithiobacillus thiooxidans
    (2021) Diaz, Mauricio; San Martin, Diego; Castro, Matias; Vera, Mario; Guiliani, Nicolas
    Acidithiobacillus species are fundamental players in biofilm formation by acidophile bioleaching communities. It has been previously reported that Acidithiobacillus ferrooxidans possesses a functional quorum sensing mediated by acyl-homoserine lactones (AHL), involved in biofilm formation, and AHLs naturally produced by Acidithiobacillus species also induce biofilm formation in Acidithiobacillus thiooxidans. A c-di-GMP pathway has been characterized in Acidithiobacillus species but it has been pointed out that the c-di-GMP effector PelD and pel-like operon are only present in the sulfur oxidizers such as A. thiooxidans. PEL exopolysaccharide has been recently involved in biofilm formation in this Acidithiobacillus species. Here, by comparing wild type and Delta pelD strains through mechanical analysis of biofilm-cells detachment, fluorescence microscopy and qPCR experiments, the structural role of PEL exopolysaccharide and the molecular network involved for its biosynthesis by A. thiooxidans were tackled. Besides, the effect of AHLs on PEL exopolysaccharide production was assessed. Mechanical resistance experiments indicated that the loss of PEL exopolysaccharide produces fragile A. thiooxidans biofilms. qRT-PCR analysis established that AHLs induce the transcription of pelA and pelD genes while epifluorescence microscopy studies revealed that PEL exopolysaccharide was required for the development of AHL-induced biofilms. Altogether these results reveal for the first time that AHLs positively regulate pel genes and participate in the molecular network for PEL exopolysaccharide biosynthesis by A. thiooxidans.
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    Real-world performance of the MiniMed 780G advanced hybrid closed loop system in Latin America: Substantial improvement in glycaemic control with each technology iteration of the MiniMed automated insulin delivery system
    (2023) Grassi, Bruno; Gomez, Ana Maria; Calliari, Luis Eduardo; Franco, Denise; Raggio, Marcela; Riera, Francisca; Castro, Matias; McVean, Jennifer; van den Heuvel, Tim; Arrieta, Arcelia; Castaneda, Javier; Cohen, Ohad
    Aim: We studied real-world performance of MiniMed (MM) 780G system users from Argentina, Brazil, Colombia and Chile (geographical analysis), and the effect of each technology iteration of the MM system on glycaemic control (technology iteration analysis).Materials and Methods: CareLink data from August 2020 to September 2022 were extracted. Endpoints included continuous glucose monitoring metrics. For the geographical analysis, aggregated endpoints for MM780G system users were calculated. For the technology iteration analysis, MM780G system user outcomes were compared with outcomes when the same individuals were still using the MM640G or MM670G system.Results: On average, 1025 MM780G system users from the geographical analysis were followed for 136 (SD 135) days, spent 91.5 (14.3)% in advanced hybrid closed loop, showed a glucose management indicator (GMI) of 6.7 (0.3)%, a time in range between 70 and 180 mg/dl (TIR) of 76.5 (9.0)%, and a time below range 70 mg/dl (TBR) of 2.7 (2.1)%. The percentage of users reaching targets of GMI < 7%, TIR > 70% and TBR < 4% was 80.8%, 78.1% and 80.1%, respectively. The technology iteration analysis on users transitioning from MM640G to MM780G system (N = 381) showed 0.4% decrease in GMI (7.1% to 6.7%, p < .0001), 10.7% increase in TIR (65.9% to 76.6%, p < .0001), while TBR remained. The percentage of insulin delivered automatically increased as well (47.5%-57.7%, p < .0001). Users transitioning from MM670G system (N = 78) showed a similar but less pronounced pattern.Conclusions: Real-world Latin American MM780G users on average showed good glucose control, achieving international targets. Glycaemic control increased with every technology iteration of the MM system, providing more automation each time.