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Vera-Gargallo B, Hernández M, Dumont MG, Ventosa A. Thrive or survive: prokaryotic life in hypersaline soils. ENVIRONMENTAL MICROBIOME 2023; 18:17. [PMID: 36915176 PMCID: PMC10012753 DOI: 10.1186/s40793-023-00475-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Soil services are central to life on the planet, with microorganisms as their main drivers. Thus, the evaluation of soil quality requires an understanding of the principles and factors governing microbial dynamics within it. High salt content is a constraint for life affecting more than 900 million hectares of land, a number predicted to rise at an alarming rate due to changing climate. Nevertheless, little is known about how microbial life unfolds in these habitats. In this study, DNA stable-isotope probing (DNA-SIP) with 18O-water was used to determine for the first time the taxa able to grow in hypersaline soil samples (ECe = 97.02 dS/m). We further evaluated the role of light on prokaryotes growth in this habitat. RESULTS We detected growth of both archaea and bacteria, with taxon-specific growth patterns providing insights into the drivers of success in saline soils. Phylotypes related to extreme halophiles, including haloarchaea and Salinibacter, which share an energetically efficient mechanism for salt adaptation (salt-in strategy), dominated the active community. Bacteria related to moderately halophilic and halotolerant taxa, such as Staphylococcus, Aliifodinibius, Bradymonadales or Chitinophagales also grew during the incubations, but they incorporated less heavy isotope. Light did not stimulate prokaryotic photosynthesis but instead restricted the growth of most bacteria and reduced the diversity of archaea that grew. CONCLUSIONS The results of this study suggest that life in saline soils is energetically expensive and that soil heterogeneity and traits such as exopolysaccharide production or predation may support growth in hypersaline soils. The contribution of phototrophy to supporting the heterotrophic community in saline soils remains unclear. This study paves the way toward a more comprehensive understanding of the functioning of these environments, which is fundamental to their management. Furthermore, it illustrates the potential of further research in saline soils to deepen our understanding of the effect of salinity on microbial communities.
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Affiliation(s)
- Blanca Vera-Gargallo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012, Sevilla, Spain
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Marcela Hernández
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Marc G Dumont
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012, Sevilla, Spain.
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Wu JH, McGenity TJ, Rettberg P, Simões MF, Li WJ, Antunes A. The archaeal class Halobacteria and astrobiology: Knowledge gaps and research opportunities. Front Microbiol 2022; 13:1023625. [PMID: 36312929 PMCID: PMC9608585 DOI: 10.3389/fmicb.2022.1023625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/07/2022] [Indexed: 09/19/2023] Open
Abstract
Water bodies on Mars and the icy moons of the outer solar system are now recognized as likely being associated with high levels of salt. Therefore, the study of high salinity environments and their inhabitants has become increasingly relevant for Astrobiology. Members of the archaeal class Halobacteria are the most successful microbial group living in hypersaline conditions and are recognized as key model organisms for exposure experiments. Despite this, data for the class is uneven across taxa and widely dispersed across the literature, which has made it difficult to properly assess the potential for species of Halobacteria to survive under the polyextreme conditions found beyond Earth. Here we provide an overview of published data on astrobiology-linked exposure experiments performed with members of the Halobacteria, identifying clear knowledge gaps and research opportunities.
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Affiliation(s)
- Jia-Hui Wu
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
| | - Terry J. McGenity
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Petra Rettberg
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Köln, Germany
| | - Marta F. Simões
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - André Antunes
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
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Ghanmi F, Carré-Mlouka A, Zarai Z, Mejdoub H, Peduzzi J, Maalej S, Rebuffat S. The extremely halophilic archaeon Halobacterium salinarum ETD5 from the solar saltern of Sfax (Tunisia) produces multiple halocins. Res Microbiol 2019; 171:80-90. [PMID: 31560985 DOI: 10.1016/j.resmic.2019.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/09/2019] [Accepted: 09/17/2019] [Indexed: 10/26/2022]
Abstract
The extremely halophilic archaeon Halobacterium salinarum strain ETD5 was previously isolated from the solar saltern of Sfax (Tunisia) and shown to encode and express halocin S8. The Hbt. salinarum ETD5 culture supernatant was shown here to exhibit high antimicrobial activity against several halophilic archaea and bacteria of different genera, showing a cross-domain inhibition. The antimicrobial activity was destroyed by proteases, thus pointing to halocins. A bioguided purification procedure was applied using two chromatography steps and antimicrobial assays directed against Halorubrum chaoviator ETR14. In-gel screening assay showed the presence of two antimicrobial bands of approximately 8 and 14 kDa, for which characterization was investigated by N-terminal sequencing and mass spectrometry. The full-length form of halocin S8 that contains 81 amino acids and differs from the 36 amino acid short-length halocin S8 previously described from an uncharacterized haloarchaeon S8a, was identified in the 8 kDa halocin band. A novel halocin that we termed halocin S14 was found in the 14 kDa band. It exhibits amino acid sequence identities with the N-terminally truncated region of the archaeal Mn-superoxide dismutase. These results show that Hbt. salinarum ETD5 produces multiple halocins, a feature that had not been described until now in the domain Archaea.
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Affiliation(s)
- Fadoua Ghanmi
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France; Laboratory of Biodiversity and Aquatic Ecosystems, Ecology and Planktonology, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Alyssa Carré-Mlouka
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
| | - Zied Zarai
- Laboratory of Plant Biotechnology, Sfax Faculty of Sciences, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Hafedh Mejdoub
- Laboratory of Plant Biotechnology, Sfax Faculty of Sciences, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Jean Peduzzi
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
| | - Sami Maalej
- Laboratory of Biodiversity and Aquatic Ecosystems, Ecology and Planktonology, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Sylvie Rebuffat
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
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Antagonistic interactions and production of halocin antimicrobial peptides among extremely halophilic prokaryotes isolated from the solar saltern of Sfax, Tunisia. Extremophiles 2016; 20:363-74. [PMID: 27074936 DOI: 10.1007/s00792-016-0827-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/24/2016] [Indexed: 10/22/2022]
Abstract
Thirty-five extremely halophilic microbial strains isolated from crystallizer (TS18) and non-crystallizer (M1) ponds in the Sfax solar saltern in Tunisia were examined for their ability to exert antimicrobial activity. Antagonistic assays resulted in the selection of eleven strains that displayed such antimicrobial activity and they were further characterized. Three cases of cross-domain inhibition (archaea/bacteria or bacteria/archaea) were observed. Four archaeal strains exerted antimicrobial activity against several other strains. Three strains, for which several lines of evidence suggested the antimicrobial activity was, at least in part, due to peptide/protein agents (Halobacterium salinarum ETD5, Hbt. salinarum ETD8, and Haloterrigena thermotolerans SS1R12), were studied further. Optimal culture conditions for growth and antimicrobial production were determined. Using DNA amplification with specific primers, sequencing and RT-PCR analysis, Hbt. salinarum ETD5 and Hbt. salinarum ETD8 were shown to encode and express halocin S8, a hydrophobic antimicrobial peptide targeting halophilic archaea. Although the gene encoding halocin H4 was amplified from the genome of Htg. thermotolerans SS1R12, no transcript could be detected and the antimicrobial activity was most likely due to multiple antimicrobial compounds. This is also the first report that points to four different strains isolated from different geographical locations with the capacity to produce identical halocin S8 proteins.
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Dammak DF, Smaoui SM, Ghanmi F, Boujelben I, Maalej S. Characterization of halo-alkaline and thermostable protease from Halorubrum ezzemoulense
strain ETR14 isolated from Sfax solar saltern in Tunisia. J Basic Microbiol 2016; 56:337-46. [DOI: 10.1002/jobm.201500475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/11/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Donyez Frikha Dammak
- Faculté des Sciences de Sfax; Université de Sfax; Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR/11ES72) Sfax; Tunisia
| | - Salma Masmoudi Smaoui
- Faculté des Sciences de Sfax; Université de Sfax; Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR/11ES72) Sfax; Tunisia
| | - Fadoua Ghanmi
- Faculté des Sciences de Sfax; Université de Sfax; Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR/11ES72) Sfax; Tunisia
| | - Ines Boujelben
- Faculté des Sciences de Sfax; Université de Sfax; Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR/11ES72) Sfax; Tunisia
| | - Sami Maalej
- Faculté des Sciences de Sfax; Université de Sfax; Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR/11ES72) Sfax; Tunisia
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Diversity of cultivable halophilic archaea and bacteria from superficial hypersaline sediments of Tunisian solar salterns. Antonie van Leeuwenhoek 2014; 106:675-92. [PMID: 25064091 DOI: 10.1007/s10482-014-0238-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/14/2014] [Indexed: 10/25/2022]
Abstract
Prokaryotes in the superficial sediments are ecologically important microorganisms that are responsible for the decomposition, mineralization and subsequent recycling of organic matter. The aim of this study was to explore the phylogenetic and functional diversity of halophilic archaea and bacteria isolated from the superficial sediments of solar salterns at Sfax, Tunisia. Sixty four strains were isolated from crystallizer (TS18) and non-crystallizer (M1) ponds and submitted to genotypic characterization and evaluation by amplified ribosomal RNA restriction analysis (ARDRA) techniques. Our findings revealed that the archaeal diversity observed for 29 isolates generated five distinct patterns from the non-crystallizer M1 pond, with Halorubrum chaoviator as the most prevalent cultivable species. However, in the TS18 crystallizer pond, ten restriction patterns were observed, with the prevalence of haloarchaea EB27K, a not yet identified genotype. The construction of a neighbour-joining tree of 16S rRNA gene sequences resulted in the division of the potential new species into two major groups, with four strains closely related to the sequence of the unculturable haloarchaeon EB27K and one strain to the recently described Halovenus aranensis strain. The 35 bacterial strains observed in this work were present only in the non-crystallizer pond (M1) and presented two distinct ARDRA patterns. These strains belonged to the γ-proteobacteria subdivision, with members of Salicola marasensis (83%) being the most predominant species among the isolates. 16S rRNA gene sequencing revealed that Salicola strains displayed different degrees of homogeneity. The results from pulsed field gel electrophoresis assays showed that the Salicola isolates could be clustered in two distinct groups with different genome sizes.
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Fröls S, Dyall-Smith M, Pfeifer F. Biofilm formation by haloarchaea. Environ Microbiol 2012; 14:3159-74. [DOI: 10.1111/j.1462-2920.2012.02895.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 08/10/2012] [Accepted: 08/28/2012] [Indexed: 11/29/2022]
Affiliation(s)
- Sabrina Fröls
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstrasse 10; 64287; Darmstadt; Germany
| | - Mike Dyall-Smith
- School of Biomedical Sciences; Charles Sturt University; Wagga Wagga; NSW; 2678; Australia
| | - Felicitas Pfeifer
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstrasse 10; 64287; Darmstadt; Germany
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