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261 results on '"Demergasso, Cecilia"'

3. Orbit-to-ground framework to decode and predict biosignature patterns in terrestrial analogues

Author

Warren-Rhodes, Kimberley, Cabrol, Nathalie A., Phillips, Michael, Tebes-Cayo, Cinthya, Kalaitzis, Freddie, Ayma, Diego, Demergasso, Cecilia, Chong-Diaz, Guillermo, Lee, Kevin, Hinman, Nancy, Rhodes, Kevin L., Boyle, Linda Ng, Bishop, Janice L., Hofmann, Michael H., Hutchinson, Neil, Javiera, Camila, Moersch, Jeffrey, Mondro, Claire, Nofke, Nora, Parro, Victor, Rodriguez, Connie, Sobron, Pablo, Sarazzin, Philippe, Wettergreen, David, and Zacny, Kris

Published
2023
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7. Microbial Community Structure and the Persistence of Cyanobacterial Populations in Salt Crusts of the Hyperarid Atacama Desert from Genome-Resolved Metagenomics

Author

Finstad, Kari M, Probst, Alexander J, Thomas, Brian C, Andersen, Gary L, Demergasso, Cecilia, Echeverría, Alex, Amundson, Ronald G, and Banfield, Jillian F

Subjects
Microbiology, Biological Sciences, Ecology, Genetics, Human Genome, Life Below Water, metagenome, Atacama Desert, salt crust, hyperarid, hypersaline, environmental genomics, salar, Environmental Science and Management, Soil Sciences, Medical microbiology
Abstract

Although once thought to be devoid of biology, recent studies have identified salt deposits as oases for life in the hyperarid Atacama Desert. To examine spatial patterns of microbial species and key nutrient sources, we genomically characterized 26 salt crusts from three sites along a fog gradient. The communities are dominated by a large variety of Halobacteriales and Bacteroidetes, plus a few algal and Cyanobacterial species. CRISPR locus analysis suggests the distribution of a single Cyanobacterial population among all sites. This is in stark contrast to the extremely high sample specificity of most other community members. Only present at the highest moisture site is a genomically characterized Thermoplasmatales archaeon (Marine Group II) and six Nanohaloarchaea, one of which is represented by a complete genome. Parcubacteria (OD1) and Saccharibacteria (TM7), not previously reported from hypersaline environments, were found at low abundances. We found no indication of a N2 fixation pathway in the communities, suggesting acquisition of bioavailable nitrogen from atmospherically derived nitrate. Samples cluster by site based on bacterial and archaeal abundance patterns and photosynthetic capacity decreases with increasing distance from the ocean. We conclude that moisture level, controlled by coastal fog intensity, is the strongest driver of community membership.

Published
2017

9. Arsenic Nanoparticles Trigger Apoptosis via Anoikis Induction in OECM-1 Cells.

Author

Covarrubias, Alejandra A., Reyna-Jeldes, Mauricio, Pedroso-Santana, Seidy, Marín, Sabrina, Madero-Mendoza, Carolina, Demergasso, Cecilia, and Coddou, Claudio

Subjects
ANOIKIS, GASTRIC mucosa, APOPTOSIS, ARSENIC, EXTRACELLULAR matrix, NANOPARTICLES
Abstract

Arsenic compounds have been used as therapeutic alternatives for several diseases including cancer. In the following work, we obtained arsenic nanoparticles (AsNPs) produced by an anaerobic bacterium from the Salar de Ascotán, in northern Chile, and evaluated their effects on the human oral squamous carcinoma cell line OECM-1. Resazurin reduction assays were carried out on these cells using 1–100 µM of AsNPs, finding a concentration-dependent reduction in cell viability that was not observed for the non-tumoral gastric mucosa-derived cell line GES-1. To establish if these effects were associated with apoptosis induction, markers like Bcl2, Bax, and cleaved caspase 3 were analyzed via Western blot, executor caspases 3/7 via luminometry, and DNA fragmentation was analyzed by TUNEL assay, using 100 µM cisplatin as a positive control. OECM-1 cells treated with AsNPs showed an induction of both extrinsic and intrinsic apoptotic pathways, which can be explained by a significant decrease in P-Akt/Akt and P-ERK/ERK relative protein ratios, and an increase in both PTEN and p53 mRNA levels and Bit-1 relative protein levels. These results suggest a prospective mechanism of action for AsNPs that involves a potential interaction with extracellular matrix (ECM) components that reduces cell attachment and subsequently triggers anoikis, an anchorage-dependent type of apoptosis. [ABSTRACT FROM AUTHOR]

Published
2024
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23. Looking for the mechanism of arsenate respiration in an arsenate-dependent growing culture of Fusibacter sp. strain 3D3, independent of ArrAB

Author

Acosta Grinok Mauricio, Susana Vázquez, Guiliani Nicolás, Sabrina Marín, and Demergasso Cecilia

Abstract

The literature has reported the isolation of arsenate-dependent growing (ADG) microorganisms which lack a canonical homolog for respiratory arsenate reductase, ArrAB. We recently isolated an ADG bacterium from arsenic-bearing environments in Northern Chile, Fusibacter sp. strain 3D3 (Fas) and studied the arsenic metabolism in this Gram-positive isolate. Features of Fas deduced from genome analysis and comparative analysis with other arsenic-reducing microorganisms revealed the lack of ArrAB coding genes and the occurrence of two arsC genes encoding for putative cytoplasmic arsenate reductases named ArsC-1 and ArsC-2. Interestingly, ArsC-1 and ArsC-2 belong to the thioredoxin-coupled family (because of the redox-active disulfide protein used as reductant), but they conferred differential AsV resistance to the E. coli WC3110 ΔarsC strain. PCR experiments confirmed the absence of arrAB genes and results obtained using uncouplers revealed that Fas growth is linked to the proton gradient. In addition, Fas harbors ferredoxin-NAD+ oxidoreductase (Rnf) coding genes. These are key molecular markers of a recently discovered flavin-based electron bifurcation mechanism involved in energy conservation, mainly in anaerobic metabolisms regulated by the cellular redox state and mostly associated with cytoplasmic enzyme complexes. At least three electron-bifurcating flavoenzyme complexes were evidenced in Fas, some of them shared in conserved genomic regions by other members of the Fusibacter genus. These physiological and genomic findings permit us to hypothesize the existence of an uncharacterized arsenate-dependent growth metabolism regulated by the cellular redox state in Fusibacter genus.

Published
2022
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27. Surface Morphologies in a Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile

Author

Hinman, Nancy W., primary, Hofmann, Michael H., additional, Warren-Rhodes, Kimberly, additional, Phillips, Michael S., additional, Noffke, Nora, additional, Cabrol, Nathalie A., additional, Chong Diaz, Guillermo, additional, Demergasso, Cecilia, additional, Tebes-Cayo, Cinthya, additional, Cabestrero, Oscar, additional, Bishop, Janice L., additional, Gulick, Virginia C., additional, Summers, David, additional, Sobron, Pablo, additional, McInenly, Michael, additional, Moersch, Jeffrey, additional, Rodriguez, Constanza, additional, Sarazzin, Philippe, additional, Rhodes, Kevin L., additional, Riffo Contreras, Camila Javiera, additional, Wettergreen, David, additional, and Parro, Victor, additional

Published
2022
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30. Time-Integrative Multibiomarker Detection in Triassic–Jurassic Rocks from the Atacama Desert: Relevance to the Search for Basic Life Beyond Earth

Author

Sánchez-García, Laura, primary, Carrizo, Daniel, additional, Lezcano, María Ángeles, additional, Moreno-Paz, Mercedes, additional, Aeppli, Christoph, additional, García-Villadangos, Miriam, additional, Prieto-Ballesteros, Olga, additional, Demergasso, Cecilia, additional, Chong, Guillermo, additional, and Parro, Victor, additional

Published
2021
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31. On the origin of saline compounds in acidic salt flats (Central Andean Altiplano)

Author

Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Xunta de Galicia, Asociación Cultural Nogará, Universidad de Barcelona, Giralt, Santiago [0000-0001-8570-7838], Pueyo, J. J., Demergasso, Cecilia S., Escudero, Lorena, Chong, Guillermo, Cortez-Rivera, P., Sanjurjo-Sánchez, J., Carmona, V., Giralt, Santiago, Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Xunta de Galicia, Asociación Cultural Nogará, Universidad de Barcelona, Giralt, Santiago [0000-0001-8570-7838], Pueyo, J. J., Demergasso, Cecilia S., Escudero, Lorena, Chong, Guillermo, Cortez-Rivera, P., Sanjurjo-Sánchez, J., Carmona, V., and Giralt, Santiago

Abstract

Volcanism, aridity, and endorheism converge in the central zone of the Andean Cordillera (Bolivia, Chile, and Argentina, between latitudes 19 degrees S and 27 degrees S). The Gorbea and Ignorado basins are pristine Andean sites in which the transfer of saline compounds from endogenous to exogenous environments occurs. In this area the regional volcanic rocks display strong argillic alteration, with Al and Fe (alunite, jarosite) and Ca (gypsum/anhydrite) sulfates. Native sulfur is also present in paleosolfataras. The Gorbea salt flat is covered by a discontinuous layer of selenitic gypsum of varying thickness (maximum 2 m). The discontinuity of the layer as well as its variable thickness is due to the fact that the original bed has been partially destroyed mainly by dissolution but also by deflation. Saline pond brines (Cl-SO4-Na [-Mg]) are strongly acidic reaching pH values lower than 2. The high temperature processes that caused the hydrothermal alteration in the Gorbea and Ignorado basins occurred in the Miocene (14 Ma) coinciding with a wet period that reached 9 Ma. Subsequently, the weather up to 120 ka was predominantly hyper-arid with a less arid interval between 6 and 3 Ma and the epithermal sulfates were recycled in saline lakes mainly in the Late Pleistocene wet period (120 to 11.7 ka). Evolution into the current salt flat occurred in the mid-early Holocene (11.7 to 4 ka), through a salt lake that first evolved into a `salina' environment that gave rise to a selenitic gypsum layer (6.4 ka), and later to the final dryness. The highest values of delta S-34(VCDT) and delta O-18(VSMOW) found in the selenitic gypsum layer (+20 parts per thousand and + 28 parts per thousand, respectively) show that the recycling was locally produced, mainly from isotopically heavier hypogene sulfates. The delta O-18(VSMOW) (and less clearly, delta S-34(VCDT)) values are higher in the basal part of the gypsum crust (about +27 parts per thousand), which suggests an initial hypogene

Published
2021

37. Addressing Strategic Knowledge Gaps in the Search for Biosignatures on Mars

Author

Cabrol, Nathalie, primary, Bishop, Janice, additional, Cady, Sherry L., additional, Demergasso, Cecilia, additional, Hinman, Nancy, additional, Hoffman, Michael, additional, Kanik, Isik, additional, Moersch, Jeffrey, additional, Noffke, Nora, additional, Parro, Victor, additional, Phillips, Cynthia, additional, Phillips, Michael, additional, Garcia, Laura Sánchez, additional, Sobron, Pablo, additional, Summers, David, additional, Warren-Rhodes, Kimberley, additional, Wettergreen, David, additional, Férnandez-Martínez, Miguel Angel, additional, and Gulick, Virginia, additional

Published
2021
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39. Dynamics of declining lake habitat in changing climate

Author

Cabrol, Nathalie A., primary, Grin, Edmond A., additional, Chong, Guillermo, additional, Häder, Donat P., additional, Minkley, Edwin, additional, Yu, Youngseob, additional, Demergasso, Cecilia, additional, Gibson, John A., additional, and Lim, Darlene, additional

Published
2010
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41. Signatures of habitats and life in Earth's high-altitude lakes: clues to Noachian aqueous environments on Mars

Author

Cabrol, Nathalie A., primary, McKay, Chris P., additional, Grin, Edmond A., additional, Kiss, Keve T., additional, Ács, Era, additional, Tóth, Balint, additional, Grigorszky, Istran, additional, Szabò, K., additional, Fike, David A., additional, Hock, Andrew N., additional, Demergasso, Cecilia, additional, Escudero, Lorena, additional, Galleguillos, P., additional, Chong, Guillermo, additional, Grigsby, Brian H., additional, Román, Jebner Zambrana, additional, and Tambley, Cristian, additional

Published
2007
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44. A test in a high altitude lake of a multi-parametric rapid methodology for assessing life in liquid environments on planetary bodies: A potential new freshwater polychaete Tubeworm community

Author

Tilot, Virginie C., Cabrol, Nathalie A., Parro, Victor, Fairén, Alberto G., Ormond, Rupert F. G., Moreno-Ostos, Enrique, Lopez-Gonzalez, Nieves, Figueroa, Fabián A., Gallardo-Carreño, Ignacio, Smith, Eric W., Sobrón, Pablo, Demergasso, Cecilia, Tambley, Cristian, Robidart, Julie, Tilot, Virginie C., Cabrol, Nathalie A., Parro, Victor, Fairén, Alberto G., Ormond, Rupert F. G., Moreno-Ostos, Enrique, Lopez-Gonzalez, Nieves, Figueroa, Fabián A., Gallardo-Carreño, Ignacio, Smith, Eric W., Sobrón, Pablo, Demergasso, Cecilia, Tambley, Cristian, and Robidart, Julie

Abstract

On our planet, aqueous environments such as deep sea or high-altitude aphotic lakes, subject to present or past volcanic activity and active deglaciation, may provide analogs to the aqueous environments found on such planetary bodies as Europa, Titan or Enceladus. We report here on the methodologies and technologies tested in Laguna Negra, a high altitude lake in the Central Andes, Chile, for exploring and assessing the presence of life within planetary lakes or interior oceans. We adopted a multi-parametric Rapid Ecological Assessment (REA) approach centered around collecting video imagery (by an Underwater Imaging System) and sampling benthic sediments (for sedimentological, biological and geochemical analysis) to depths of 272 m, to complement physico-chemical sampling of the water column and collection of shallow sediments for microbiological analysis (reported in separate publications). This enabled us to classify and assess the apparent status of benthic habitats, based on substrata and environmental characteristics, together with floral and faunal community characteristics and bioturbation artifacts. Video imagery showed that the lower water column was characterized by a variably intense sestonic flux of particles and debris, among which were planktonic organisms such as ostracods, copepods, and possibly cladocerans. Sediment analysis revealed at all depths abundant diatom frustules, mainly of an acidophile pennade diatom Pinnularia acidicola, amid vegetal debris likely originating from littoral macrophytes. Video imagery showed that the lakebed was partly covered by microbial mats and depositional matter and harbored an unexpectedly rich assortment of macrofauna, including sponges, tubificid worms, flatworms, bivalves and crustaceans. Various forms of bioturbation were also encountered, some with the animals in the tracks. Most notably, at the deepest site, a previously undescribed faunal feature was evident, apparently formed by a mat-like community of seve

Published
2019

46. A Test in a High Altitude Lake of a Multi-Parametric Rapid Methodology for Assessing Life in Liquid Environments on Planetary Bodies: A Potential New Freshwater Polychaete Tubeworm Community

Author

Tilot, Virginie C., primary, Cabrol, Nathalie A., additional, Parro, Victor, additional, Fairén, Alberto G., additional, Ormond, Rupert F. G., additional, Moreno-Ostos, Enrique, additional, Lopez-Gonzalez, Nieves, additional, Figueroa, Fabián A., additional, Gallardo-Carreño, Ignacio, additional, Smith, Eric W., additional, Sobrón, Pablo, additional, Demergasso, Cecilia, additional, Tambley, Cristian, additional, and Robidart, Julie, additional

Published
2019
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48. Microbiology and Nitrogen Cycle in the Benthic Sediments of a Glacial Oligotrophic Deep Andean Lake as Analog of Ancient Martian Lake-Beds

Author

Parro, Victor, primary, Puente-Sánchez, Fernando, additional, Cabrol, Nathalie A., additional, Gallardo-Carreño, Ignacio, additional, Moreno-Paz, Mercedes, additional, Blanco, Yolanda, additional, García-Villadangos, Miriam, additional, Tambley, Cristian, additional, Tilot, Virginie C., additional, Thompson, Cody, additional, Smith, Eric, additional, Sobrón, Pablo, additional, Demergasso, Cecilia S., additional, Echeverría-Vega, Alex, additional, Fernández-Martínez, Miguel Ángel, additional, Whyte, Lyle G., additional, and Fairén, Alberto G., additional

Published
2019
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50. Additional file 1: Figure S1. of First draft genome sequence of a strain from the genus Fusibacter isolated from Salar de Ascotรกn in Northern Chile

Author

Serrano, Antonio, Escudero, Lorena, Tebes-Cayo, Cinthya, Acosta, Mauricio, Encalada, Olga, Sebastiรกn Fernรกndez-Moroso, and Demergasso, Cecilia

Abstract

CLUSTAL multiple sequence alignment of proteins related to WP_069871897 of Fusibacter sp. strain 3D3. (ALN 76400 bytes). (DOCX 38 kb)

Published
2017
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