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Remonsellez F, Castro-Severyn J, Pardo-Esté C, Aguilar P, Fortt J, Salinas C, Barahona S, León J, Fuentes B, Areche C, Hernández KL, Aguayo D, Saavedra CP. Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium sp. SH31 Isolated From Sediments of Salar de Huasco, Chilean Altiplano. Front Microbiol 2018; 9:2228. [PMID: 30294311 PMCID: PMC6158405 DOI: 10.3389/fmicb.2018.02228] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/31/2018] [Indexed: 12/22/2022] Open
Abstract
Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival.
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Affiliation(s)
- Francisco Remonsellez
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Antofagasta, Chile
| | - Juan Castro-Severyn
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Coral Pardo-Esté
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Pablo Aguilar
- Lake and Glacier Ecology Research Group, Institute of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jonathan Fortt
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Cesar Salinas
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Sergio Barahona
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Joice León
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Bárbara Fuentes
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Carlos Areche
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Klaudia L. Hernández
- Centro de Investigación Marina Quintay, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel Aguayo
- Center for Bioinformatics and Integrative Biology, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Claudia P. Saavedra
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
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Hernández KL, Yannicelli B, Olsen LM, Dorador C, Menschel EJ, Molina V, Remonsellez F, Hengst MB, Jeffrey WH. Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano. Front Microbiol 2016; 7:1857. [PMID: 27920763 PMCID: PMC5118629 DOI: 10.3389/fmicb.2016.01857] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 11/04/2016] [Indexed: 11/13/2022] Open
Abstract
In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, 3H-leucine incorporation) response from short-term exposures to solar radiation. We sampled during austral spring seven stations categorized as: (a) source stations, with recently emerged groundwater (no-previous solar exposure); (b) stream running water stations; (c) stations connected to source waters but far downstream from source points; and (d) isolated ponds disconnected from ground sources or streams with a longer isolation and solar exposure history. Very high values of 0.25 μE m-2 s-1, 72 W m-2 and 12 W m-2 were measured for PAR, UVA, and UVB incident solar radiation, respectively. The environmental factors measured formed two groups of stations reflected by principal component analyses (near to groundwater sources and isolated systems) where isolated ponds had the highest BSP and microbial abundance (35 microalgae taxa, picoeukaryotes, nanoflagellates, and bacteria) plus higher salinities and PO43- concentrations. BSP short-term response (4 h) to solar radiation was measured by 3H-leucine incorporation under four different solar conditions: full sun, no UVB, PAR, and dark. Microbial communities established in waters with the longest surface exposure (e.g., isolated ponds) had the lowest BSP response to solar radiation treatments, and thus were likely best adapted to solar radiation exposure contrary to ground source waters. These results support our light history (solar exposure) hypothesis where the more isolated the community is from ground water sources, the better adapted it is to solar radiation. We suggest that factors other than solar radiation (e.g., salinity, PO43-, NO3-) are also important in determining microbial productivity in heterogeneous environments such as the Salar de Huasco.
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Affiliation(s)
- Klaudia L Hernández
- Centro de Investigación Marina Quintay CIMARQ, Facultad de Ecología y Recursos Naturales, Universidad Andres BelloSantiago, Chile; Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de ChileValdivia, Chile
| | - Beatriz Yannicelli
- Centro de Estudios Avanzados en Zonas AridasLa Serena, Chile; Facultad de Ciencias del Mar, Universidad Católica del NorteCoquimbo, Chile; Ecology and Sustainable Management of Oceanic Islands, Universidad Católica del Norte, CoquimboCoquimbo, Chile; Centro Universitario de la Región Este, Universidad de la RepúblicaRocha, Uruguay
| | | | - Cristina Dorador
- Laboratorio de Complejidad Microbiana y Ecología Funcional and Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de AntofagastaAntofagasta, Chile; Centro de Biotecnología y BioingenieríaSantiago, Chile
| | - Eduardo J Menschel
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de ChileValdivia, Chile; Programa de Postgrado en Oceanografía, Departamento de Oceanografía, Universidad de ConcepciónConcepción, Chile; Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (FONDAP-IDEAL), Universidad Austral de ChileValdivia-Punta Arenas, Chile
| | - Verónica Molina
- Departamento de Biología, Observatorio de Ecología Microbiana, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha Valparaíso, Chile
| | - Francisco Remonsellez
- Laboratorio de Microbiología Aplicada y Extremófilos, Departamento de Ingeniería Química, Universidad Católica del Norte Antofagasta, Chile
| | - Martha B Hengst
- Centro de Biotecnología y BioingenieríaSantiago, Chile; Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del NorteAntofagasta, Chile
| | - Wade H Jeffrey
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola FL, USA
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