1
|
Fischer FC, Schulze-Makuch D, Heinz J. Microbial preference for chlorate over perchlorate under simulated shallow subsurface Mars-like conditions. Sci Rep 2024; 14:11537. [PMID: 38773211 PMCID: PMC11109124 DOI: 10.1038/s41598-024-62346-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024] Open
Abstract
The Martian surface and shallow subsurface lacks stable liquid water, yet hygroscopic salts in the regolith may enable the transient formation of liquid brines. This study investigated the combined impact of water scarcity, UV exposure, and regolith depth on microbial survival under Mars-like environmental conditions. Both vegetative cells of Debaryomyces hansenii and Planococcus halocryophilus, alongside with spores of Aspergillus niger, were exposed to an experimental chamber simulating Martian environmental conditions (constant temperatures of about - 11 °C, low pressure of approximately 6 mbar, a CO2 atmosphere, and 2 h of daily UV irradiation). We evaluated colony-forming units (CFU) and water content at three different regolith depths before and after exposure periods of 3 and 7 days, respectively. Each organism was tested under three conditions: one without the addition of salts to the regolith, one containing sodium chlorate, and one with sodium perchlorate. Our results reveal that the residual water content after the exposure experiments increased with regolith depth, along with the organism survival rates in chlorate-containing and salt-free samples. The survival rates of the three organisms in perchlorate-containing regolith were consistently lower for all organisms and depths compared to chlorate, with the most significant difference being observed at a depth of 10-12 cm, which corresponds to the depth with the highest residual water content. The postulated reason for this is an increase in the salt concentration at this depth due to the freezing of water, showing that for these organisms, perchlorate brines are more toxic than chlorate brines under the experimental conditions. This underscores the significance of chlorate salts when considering the habitability of Martian environments.
Collapse
Affiliation(s)
- Florian Carlo Fischer
- Center for Astronomy and Astrophysics, RG Astrobiology, Technische Universität Berlin, Berlin, Germany
| | - Dirk Schulze-Makuch
- Center for Astronomy and Astrophysics, RG Astrobiology, Technische Universität Berlin, Berlin, Germany
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Jacob Heinz
- Center for Astronomy and Astrophysics, RG Astrobiology, Technische Universität Berlin, Berlin, Germany.
| |
Collapse
|
2
|
Hallsworth JE, Udaondo Z, Pedrós‐Alió C, Höfer J, Benison KC, Lloyd KG, Cordero RJB, de Campos CBL, Yakimov MM, Amils R. Scientific novelty beyond the experiment. Microb Biotechnol 2023; 16:1131-1173. [PMID: 36786388 PMCID: PMC10221578 DOI: 10.1111/1751-7915.14222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 02/15/2023] Open
Abstract
Practical experiments drive important scientific discoveries in biology, but theory-based research studies also contribute novel-sometimes paradigm-changing-findings. Here, we appraise the roles of theory-based approaches focusing on the experiment-dominated wet-biology research areas of microbial growth and survival, cell physiology, host-pathogen interactions, and competitive or symbiotic interactions. Additional examples relate to analyses of genome-sequence data, climate change and planetary health, habitability, and astrobiology. We assess the importance of thought at each step of the research process; the roles of natural philosophy, and inconsistencies in logic and language, as drivers of scientific progress; the value of thought experiments; the use and limitations of artificial intelligence technologies, including their potential for interdisciplinary and transdisciplinary research; and other instances when theory is the most-direct and most-scientifically robust route to scientific novelty including the development of techniques for practical experimentation or fieldwork. We highlight the intrinsic need for human engagement in scientific innovation, an issue pertinent to the ongoing controversy over papers authored using/authored by artificial intelligence (such as the large language model/chatbot ChatGPT). Other issues discussed are the way in which aspects of language can bias thinking towards the spatial rather than the temporal (and how this biased thinking can lead to skewed scientific terminology); receptivity to research that is non-mainstream; and the importance of theory-based science in education and epistemology. Whereas we briefly highlight classic works (those by Oakes Ames, Francis H.C. Crick and James D. Watson, Charles R. Darwin, Albert Einstein, James E. Lovelock, Lynn Margulis, Gilbert Ryle, Erwin R.J.A. Schrödinger, Alan M. Turing, and others), the focus is on microbiology studies that are more-recent, discussing these in the context of the scientific process and the types of scientific novelty that they represent. These include several studies carried out during the 2020 to 2022 lockdowns of the COVID-19 pandemic when access to research laboratories was disallowed (or limited). We interviewed the authors of some of the featured microbiology-related papers and-although we ourselves are involved in laboratory experiments and practical fieldwork-also drew from our own research experiences showing that such studies can not only produce new scientific findings but can also transcend barriers between disciplines, act counter to scientific reductionism, integrate biological data across different timescales and levels of complexity, and circumvent constraints imposed by practical techniques. In relation to urgent research needs, we believe that climate change and other global challenges may require approaches beyond the experiment.
Collapse
Affiliation(s)
- John E. Hallsworth
- Institute for Global Food Security, School of Biological SciencesQueen's University BelfastBelfastUK
| | - Zulema Udaondo
- Department of Biomedical InformaticsUniversity of Arkansas for Medical SciencesLittle RockArkansasUSA
| | - Carlos Pedrós‐Alió
- Department of Systems BiologyCentro Nacional de Biotecnología (CSIC)MadridSpain
| | - Juan Höfer
- Escuela de Ciencias del MarPontificia Universidad Católica de ValparaísoValparaísoChile
| | - Kathleen C. Benison
- Department of Geology and GeographyWest Virginia UniversityMorgantownWest VirginiaUSA
| | - Karen G. Lloyd
- Microbiology DepartmentUniversity of TennesseeKnoxvilleTennesseeUSA
| | - Radamés J. B. Cordero
- Department of Molecular Microbiology and ImmunologyJohns Hopkins Bloomberg School of Public HealthBaltimoreMarylandUSA
| | - Claudia B. L. de Campos
- Institute of Science and TechnologyUniversidade Federal de Sao Paulo (UNIFESP)São José dos CamposSPBrazil
| | | | - Ricardo Amils
- Department of Molecular Biology, Centro de Biología Molecular Severo Ochoa (CSIC‐UAM)Nicolás Cabrera n° 1, Universidad Autónoma de MadridMadridSpain
- Department of Planetology and HabitabilityCentro de Astrobiología (INTA‐CSIC)Torrejón de ArdozSpain
| |
Collapse
|
3
|
Acar M, Tatini D, Ninham BW, Rossi F, Marchettini N, Lo Nostro P. The Lyotropic Nature of Halates: An Experimental Study. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238519. [PMID: 36500616 PMCID: PMC9739596 DOI: 10.3390/molecules27238519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
Unlike halides, where the kosmotropicity decreases from fluoride to iodide, the kosmotropic nature of halates apparently increases from chlorate to iodate, in spite of the lowering in the static ionic polarizability. In this paper, we present an experimental study that confirms the results of previous simulations. The lyotropic nature of aqueous solutions of sodium halates, i.e., NaClO3, NaBrO3, and NaIO3, is investigated through density, conductivity, viscosity, and refractive index measurements as a function of temperature and salt concentration. From the experimental data, we evaluate the activity coefficients and the salt polarizability and assess the anions' nature in terms of kosmotropicity/chaotropicity. The results clearly indicate that iodate behaves as a kosmotrope, while chlorate is a chaotrope, and bromate shows an intermediate nature. This experimental study confirms that, in the case of halates XO3-, the kosmotropic-chaotropic ranking reverses with respect to halides. We also discuss and revisit the role of the anion's polarizability in the interpretation of Hofmeister phenomena.
Collapse
Affiliation(s)
- Mert Acar
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Duccio Tatini
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
| | - Barry W. Ninham
- Materials Physics (Formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT 2600, Australia
- School of Science, University of New South Wales, Northcott Drive, Campbell, Canberra, ACT 2612, Australia
| | - Federico Rossi
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Nadia Marchettini
- Department of Earth, Environmental and Physical Sciences, University of Siena, 53100 Siena, Italy
| | - Pierandrea Lo Nostro
- Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, 50019 Firenze, Italy
- Correspondence: ; Tel.: +39-055-4573010
| |
Collapse
|
4
|
Cassaro A, Pacelli C, Onofri S. Survival, metabolic activity, and ultrastructural damages of Antarctic black fungus in perchlorates media. Front Microbiol 2022; 13:992077. [PMID: 36523839 PMCID: PMC9744811 DOI: 10.3389/fmicb.2022.992077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/06/2022] [Indexed: 09/12/2023] Open
Abstract
Evidence from recent Mars landers identified the presence of perchlorates salts at 1 wt % in regolith and their widespread distribution on the Martian surface that has been hypothesized as a critical chemical hazard for putative life forms. However, the hypersaline environment may also potentially preserve life and its biomolecules over geological timescales. The high concentration of natural perchlorates is scarcely reported on Earth. The presence of perchlorates in soil and ice has been recorded in some extreme environments including the McMurdo Dry Valleys in Antarctica, one of the best terrestrial analogues for Mars. In the frame of "Life in space" Italian astrobiology project, the polyextremophilic black fungus Cryomyces antarcticus, a eukaryotic test organism isolated from the Antarctic cryptoendolithic communities, has been tested for its resistance, when grown on different hypersaline substrata. In addition, C. antarcticus was grown on Martian relevant perchlorate medium (0.4 wt% of Mg(ClO4)2 and 0.6 wt% of Ca(ClO4)2) to investigate the possibility for the fungus to survive in Martian environment. Here, the results indicate a good survivability and metabolic activity recovery of the black fungus when grown on four Martian relevant perchlorates. A low percentage of damaged cellular membranes have been found, confirming the ultrastructural investigation.
Collapse
Affiliation(s)
- Alessia Cassaro
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università snc, Viterbo, Italy
| | - Claudia Pacelli
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università snc, Viterbo, Italy
- Human Spaceflight and Scientific Research Unit, Italian Space Agency, via del Politecnico, Rome, Italy
| | - Silvano Onofri
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università snc, Viterbo, Italy
| |
Collapse
|
5
|
Heinz J, Doellinger J, Maus D, Schneider A, Lasch P, Grossart HP, Schulze-Makuch D. Perchlorate-Specific Proteomic Stress Responses of Debaryomyces hansenii Could Enable Microbial Survival in Martian Brines. Environ Microbiol 2022; 24:5051-5065. [PMID: 35920032 DOI: 10.1111/1462-2920.16152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022]
Abstract
If life exists on Mars, it would face several challenges including the presence of perchlorates, which destabilize biomacromolecules by inducing chaotropic stress. However, little is known about perchlorate toxicity for microorganism on the cellular level. Here we present the first proteomic investigation on the perchlorate-specific stress responses of the halotolerant yeast Debaryomyces hansenii and compare these to generally known salt stress adaptations. We found that the responses to NaCl and NaClO4 -induced stresses share many common metabolic features, e.g., signaling pathways, elevated energy metabolism, or osmolyte biosynthesis. Nevertheless, several new perchlorate-specific stress responses could be identified, such as protein glycosylation and cell wall remodulations, presumably in order to stabilize protein structures and the cell envelope. These stress responses would also be relevant for life on Mars, which - given the environmental conditions - likely developed chaotropic defense strategies such as stabilized confirmations of biomacromolecules and the formation of cell clusters. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Jacob Heinz
- Center for Astronomy and Astrophysics, RG Astrobiology, Technische Universität Berlin, Berlin, Germany
| | - Joerg Doellinger
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens, Proteomics and Spectroscopy (ZBS6), Berlin, Germany
| | - Deborah Maus
- Robert Koch-Institute, Metabolism of Microbial Pathogens (NG2), Berlin, Germany
| | - Andy Schneider
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens, Proteomics and Spectroscopy (ZBS6), Berlin, Germany
| | - Peter Lasch
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens, Proteomics and Spectroscopy (ZBS6), Berlin, Germany
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany.,Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany
| | - Dirk Schulze-Makuch
- Center for Astronomy and Astrophysics, RG Astrobiology, Technische Universität Berlin, Berlin, Germany.,Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany.,GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany.,School of the Environment, Washington State University, Pullman, Washington, USA
| |
Collapse
|
6
|
Weingarten EA, Zee PC, Jackson CR. Microbial Communities in Saltpan Sediments Show Tolerance to Mars Analog Conditions, but Susceptibility to Chloride and Perchlorate Toxicity. ASTROBIOLOGY 2022; 22:838-850. [PMID: 35731161 PMCID: PMC9464085 DOI: 10.1089/ast.2021.0132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 02/28/2022] [Indexed: 06/15/2023]
Abstract
Brines at or near the surface of present-day Mars are a potential explanation for seasonally recurring dark streaks on the walls of craters, termed recurring slope lineae (RSL). Deliquescence and freezing point depression are possible drivers of brine stability, attributable to the high salinity observed in martian regolith including chlorides and perchlorates. Investigation of life, which may inhabit RSL, and the cellular mechanisms necessary for survival, must consider the tolerance of highly variable hydration, freeze-thaw cycles, and high osmolarity in addition to the anaerobic, oligotrophic, and irradiated environment. We propose the saltpan, an ephemeral, hypersaline wetland as an analogue for putative RSL hydrology. Saltpan sediment archaeal and bacterial communities showed tolerance of the Mars-analogous atmosphere, hydration, minerology, salinity, and temperature. Although active growth and a shift to well-adapted taxa were observed, susceptibility to low-concentration chloride and perchlorate addition suggested that such a composition was insufficient for beneficial water retention relative to added salt stress.
Collapse
Affiliation(s)
- Eric A. Weingarten
- Department of Biology, University of Mississippi, University, Mississippi, USA
- U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi, USA
| | - Peter C. Zee
- Department of Biology, University of Mississippi, University, Mississippi, USA
| | - Colin R. Jackson
- Department of Biology, University of Mississippi, University, Mississippi, USA
| |
Collapse
|
7
|
Nguyen K, Kumar P. Morphological Phenotypes, Cell Division, and Gene Expression of Escherichia coli under High Concentration of Sodium Sulfate. Microorganisms 2022; 10:microorganisms10020274. [PMID: 35208727 PMCID: PMC8875244 DOI: 10.3390/microorganisms10020274] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 01/10/2023] Open
Abstract
Sodium and sulfate ions are among the suggested abundant ions on Europa, a moon of Jupiter. In order to investigate the potential habitability of Europa, we study the effects of sodium sulfate (Na2SO4) on a non-halophilic bacterium by subjecting Escherichia coli (E. coli) to a wide range of Na2SO4 concentrations (0–1.0 m). We discover that, as the concentration of sodium sulfate increases, the biomass doubling time increases and the cell growth is completely inhibited at 1.0 m Na2SO4. Furthermore, we find that E. coli exhibits three distinct morphological phenotypes—(i) shortened, (ii) normal, and (iii) elongated/filamented cells at 0.6 m and 0.8 m Na2SO4. We have examined the expression of different genes involved in sodium and sulfate transport (nhaA, nhaB, cysZ, sbp), osmotically driven transport of water (aqpZ), sulfate metabolism (cysN), fatty acid production (fabA), and a global transcriptional regulator (osmZ). Our results suggest that the expression of these genes is not affected significantly at high concentrations of sodium sulfate in the exponential growth phase. Using our experimental data and the existing data in the literature, we show that the osmotic pressure difference may play a major role in determining the growth inhibition of E. coli and B. subtilis at high concentrations of salt.
Collapse
|