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Riekeles M, Santos B, Youssef SAM, Schulze-Makuch D. Viability and Motility of Escherichia coli Under Elevated Martian Salt Stresses. Life (Basel) 2024; 14:1526. [PMID: 39768235 PMCID: PMC11676641 DOI: 10.3390/life14121526] [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: 10/17/2024] [Revised: 11/11/2024] [Accepted: 11/19/2024] [Indexed: 01/11/2025] Open
Abstract
This study investigates the effects of three Martian-relevant salts-sodium chlorate, sodium perchlorate, and sodium chloride-on the viability and motility of Escherichia coli, a model organism for understanding microbial responses to environmental stress. These salts are abundant on Mars and play a crucial role in forming brines, one of the few sources of stable liquid water on the planet. We analyze the survivability under different salt concentrations using colony plating. Additionally, we perform a semi-automated motility analysis, analyzing microbial speeds and motility patterns. Our results show that sodium perchlorate is the most toxic, followed by sodium chlorate, with sodium chloride being the least harmful. Both survivability and motility are affected by salt concentration and exposure time. Notably, we observe a short-lived increase in motility at certain concentrations, particularly under sodium chlorate and sodium perchlorate stress, despite rapid declines in cell viability, suggesting a stress response mechanism. Given that motility might enhance an organism's ability to navigate harsh and variable environments, it holds promise as a key biosignature in the search for life on Mars.
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Affiliation(s)
- Max Riekeles
- Astrobiology Group, Center of Astronomy and Astrophysics, Technical University Berlin, 10623 Berlin, Germany; (B.S.); (S.A.-M.Y.); (D.S.-M.)
| | - Berke Santos
- Astrobiology Group, Center of Astronomy and Astrophysics, Technical University Berlin, 10623 Berlin, Germany; (B.S.); (S.A.-M.Y.); (D.S.-M.)
- Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Sherif Al-Morssy Youssef
- Astrobiology Group, Center of Astronomy and Astrophysics, Technical University Berlin, 10623 Berlin, Germany; (B.S.); (S.A.-M.Y.); (D.S.-M.)
| | - Dirk Schulze-Makuch
- Astrobiology Group, Center of Astronomy and Astrophysics, Technical University Berlin, 10623 Berlin, Germany; (B.S.); (S.A.-M.Y.); (D.S.-M.)
- Section Geomicrobiology, German Research Centre for Geosciences (GFZ), 14473 Potsdam, Germany
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Stechlin, Germany
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2
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Kaur J, Kaur J, Nigam A. Extremophiles in Space Exploration. Indian J Microbiol 2024; 64:418-428. [PMID: 39010991 PMCID: PMC11246395 DOI: 10.1007/s12088-024-01297-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 04/28/2024] [Indexed: 07/17/2024] Open
Abstract
In the era of deep space exploration, extremophile research represents a key area of research w.r.t space survival. This review thus delves into the intriguing realm of 'Space and Astro Microbiology', providing insights into microbial survival, resilience, and behavioral adaptations in space-like environments. This discussion encompasses the modified behavior of extremophilic microorganisms, influencing virulence, stress resistance, and gene expression. It then shifts to recent studies on the International Space Station and simulated microgravity, revealing microbial responses that impact drug susceptibility, antibiotic resistance, and its commercial implications. The review then transitions into Astro microbiology, exploring the possibilities of interplanetary transit, lithopanspermia, and terraforming. Debates on life's origin and recent Martian meteorite discoveries are noted. We also discuss Proactive Inoculation Protocols for selecting adaptable microorganisms as terraforming pioneers. The discussion concludes with a note on microbes' role as bioengineers in bioregenerative life support systems, in recycling organic waste for sustainable space travel; and in promoting optimal plant growth to prepare Martian and lunar basalt. This piece emphasizes the transformative impact of microbes on the future of space exploration.
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Affiliation(s)
- Jasvinder Kaur
- Gargi College, University of Delhi, Siri Fort Road, New Delhi, 110 049 India
| | - Jaspreet Kaur
- Maitreyi College, University of Delhi, New Delhi, 110 021 India
| | - Aeshna Nigam
- Shivaji College, University of Delhi, New Delhi, 110 027 India
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3
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Malaterre C, Ten Kate IL, Baqué M, Debaille V, Grenfell JL, Javaux EJ, Khawaja N, Klenner F, Lara YJ, McMahon S, Moore K, Noack L, Patty CHL, Postberg F. Is There Such a Thing as a Biosignature? ASTROBIOLOGY 2023; 23:1213-1227. [PMID: 37962841 DOI: 10.1089/ast.2023.0042] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The concept of a biosignature is widely used in astrobiology to suggest a link between some observation and a biological cause, given some context. The term itself has been defined and used in several ways in different parts of the scientific community involved in the search for past or present life on Earth and beyond. With the ongoing acceleration in the search for life in distant time and/or deep space, there is a need for clarity and accuracy in the formulation and reporting of claims. Here, we critically review the biosignature concept(s) and the associated nomenclature in light of several problems and ambiguities emphasized by recent works. One worry is that these terms and concepts may imply greater certainty than is usually justified by a rational interpretation of the data. A related worry is that terms such as "biosignature" may be inherently misleading, for example, because the divide between life and non-life-and their observable effects-is fuzzy. Another worry is that different parts of the multidisciplinary community may use non-equivalent or conflicting definitions and conceptions, leading to avoidable confusion. This review leads us to identify a number of pitfalls and to suggest how they can be circumvented. In general, we conclude that astrobiologists should exercise particular caution in deciding whether and how to use the concept of biosignature when thinking and communicating about habitability or life. Concepts and terms should be selected carefully and defined explicitly where appropriate. This would improve clarity and accuracy in the formulation of claims and subsequent technical and public communication about some of the most profound and important questions in science and society. With this objective in mind, we provide a checklist of questions that scientists and other interested parties should ask when assessing any reported detection of a "biosignature" to better understand exactly what is being claimed.
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Affiliation(s)
- Christophe Malaterre
- Département de philosophie, Chaire de recherche du Canada en philosophie des sciences de la vie, Université du Québec à Montréal (UQAM), Montréal, Québec, Canada
- Centre interuniversitaire de recherche sur la science et la technologie (CIRST), Université du Québec à Montréal (UQAM), Montréal, Québec, Canada
| | - Inge Loes Ten Kate
- Department of Earth Sciences, Utrecht University, Utrecht, the Netherlands
| | - Mickael Baqué
- Planetary Laboratories Department, Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Vinciane Debaille
- Laboratoire G-Time, Université libre de Bruxelles, Brussels, Belgium
| | - John Lee Grenfell
- Department of Extrasolar Planets and Atmospheres, Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Emmanuelle J Javaux
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, Liège, Belgium
| | - Nozair Khawaja
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Fabian Klenner
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA
| | - Yannick J Lara
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, Liège, Belgium
| | - Sean McMahon
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keavin Moore
- Department of Earth & Planetary Sciences, McGill University, Montreal, Québec, Canada
- Trottier Space Institute, McGill University, Montreal, Québec, Canada
| | - Lena Noack
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - C H Lucas Patty
- Physikalisches Institut, Universität Bern, Bern, Switzerland
- Center for Space and Habitability, Universität Bern, Bern, Switzerland
| | - Frank Postberg
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
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4
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Gillen C, Jeancolas C, McMahon S, Vickers P. The Call for a New Definition of Biosignature. ASTROBIOLOGY 2023; 23:1228-1237. [PMID: 37819715 DOI: 10.1089/ast.2023.0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
The term biosignature has become increasingly prevalent in astrobiology literature as our ability to search for life advances. Although this term has been useful to the community, its definition is not settled. Existing definitions conflict sharply over the balance of evidence needed to establish a biosignature, which leads to misunderstanding and confusion about what is being claimed when biosignatures are purportedly detected. To resolve this, we offer a new definition of a biosignature as any phenomenon for which biological processes are a known possible explanation and whose potential abiotic causes have been reasonably explored and ruled out. This definition is strong enough to do the work required of it in multiple contexts-from the search for life on Mars to exoplanet spectroscopy-where the quality and indeed quantity of obtainable evidence is markedly different. Moreover, it addresses the pernicious problem of unconceived abiotic mimics that is central to biosignature research. We show that the new definition yields intuitively satisfying judgments when applied to historical biosignature claims. We also reaffirm the importance of multidisciplinary work on abiotic mimics to narrow the gap between the detection of a biosignature and a confirmed discovery of life.
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5
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Tang JWT, Henriques A, Loh TP. Microbes and space travel - hope and hazards. Future Microbiol 2021; 16:1023-1028. [PMID: 34488427 DOI: 10.2217/fmb-2021-0196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Julian Wei-Tze Tang
- C/O Clinical Microbiology, 5/F Sandringham Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK
| | - Andre Henriques
- CERN (European Organisation for Nuclear Research), Geneva, Switzerland
| | - Tze Ping Loh
- Laboratory Medicine, National University Hospital, Singapore
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6
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Marshall SM, Mathis C, Carrick E, Keenan G, Cooper GJT, Graham H, Craven M, Gromski PS, Moore DG, Walker SI, Cronin L. Identifying molecules as biosignatures with assembly theory and mass spectrometry. Nat Commun 2021; 12:3033. [PMID: 34031398 PMCID: PMC8144626 DOI: 10.1038/s41467-021-23258-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/07/2021] [Indexed: 01/14/2023] Open
Abstract
The search for alien life is hard because we do not know what signatures are unique to life. We show why complex molecules found in high abundance are universal biosignatures and demonstrate the first intrinsic experimentally tractable measure of molecular complexity, called the molecular assembly index (MA). To do this we calculate the complexity of several million molecules and validate that their complexity can be experimentally determined by mass spectrometry. This approach allows us to identify molecular biosignatures from a set of diverse samples from around the world, outer space, and the laboratory, demonstrating it is possible to build a life detection experiment based on MA that could be deployed to extraterrestrial locations, and used as a complexity scale to quantify constraints needed to direct prebiotically plausible processes in the laboratory. Such an approach is vital for finding life elsewhere in the universe or creating de-novo life in the lab.
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Affiliation(s)
| | - Cole Mathis
- School of Chemistry, University of Glasgow, Glasgow, UK
| | - Emma Carrick
- School of Chemistry, University of Glasgow, Glasgow, UK
| | - Graham Keenan
- School of Chemistry, University of Glasgow, Glasgow, UK
| | | | - Heather Graham
- Astrobiology Analytical Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | | | - Douglas G Moore
- Beyond Centre for Concepts in Fundamental Science, Arizona State University, Tempe, AZ, USA
| | - Sara I Walker
- Beyond Centre for Concepts in Fundamental Science, Arizona State University, Tempe, AZ, USA
| | - Leroy Cronin
- School of Chemistry, University of Glasgow, Glasgow, UK.
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7
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Machine Learning Algorithms Applied to Identify Microbial Species by Their Motility. Life (Basel) 2021; 11:life11010044. [PMID: 33445805 PMCID: PMC7828299 DOI: 10.3390/life11010044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 01/24/2023] Open
Abstract
(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms. The technology was not advanced enough for onboard machine analysis of microscopic observations to be performed in past missions, but recent increases in computational power make the use of automated in-situ analyses feasible. (2) Methods: Here, we present a semi-automated experimental setup, capable of distinguishing the movement of abiotic particles due to Brownian motion from the motility behavior of the bacteria Pseudoalteromonas haloplanktis, Planococcus halocryophilus, Bacillus subtilis, and Escherichia coli. Supervised machine learning algorithms were also used to specifically identify these species based on their characteristic motility behavior. (3) Results: While we were able to distinguish microbial motility from the abiotic movements due to Brownian motion with an accuracy exceeding 99%, the accuracy of the automated identification rates for the selected species does not exceed 82%. (4) Conclusions: Motility is an excellent biosignature, which can be used as a tool for upcoming life-detection missions. This study serves as the basis for the further development of a microscopic life recognition system for upcoming missions to Mars or the ocean worlds of the outer Solar System.
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8
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Xing W, Hu H, Zhang Y, Zhao D, Wang W, Pan H, Zhang S, Yan L. Magnetotactic bacteria diversity of and magnetism contribution to sediment in Wudalianchi volcanic barrier lakes, NE China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137348. [PMID: 32088486 DOI: 10.1016/j.scitotenv.2020.137348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/02/2020] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Magnetotactic bacteria (MTB), the members of sediment microorganisms, play an important role in geochemical iron-cycling and sediment magnetism. This study aimed to investigate the diversity and magnetism contribution of MTB in three volcanic barrier lakes with different waterbody types (open waterbody, YC; semi-enclosed waterbody, WB; and enclosed waterbody, YYP). High-throughput sequencing results showed that MTB affiliated to Alphaproteobacteria, Betaproteobacteria and Nitrospira distributed widely in these lakes. The genera of Magnetococcus (98.10%) and Candidatus Magnetoovum (1.47%) were endemic to YC and WB, respectively. The changes in frequency-dependent susceptibility (χfd) values before and after magnetic collection in YC, WB and YYP samples were - 0.28%, 0.05% and - 0.22%, respectively. The magnetic susceptibility was significantly associated with Chao1 (R2 = 0.637 to 0.763, p < .01) and Shannon index (R2 = 0.803 to 0.998, p < .01). The room- and low-temperature magnetic characteristics of sediment samples were analyzed by vibrating sample magnetometer (VSM) and radio-frequency superconducting quantum interference device (SQUID). Results indicated that the presence or absence of MTB could lead to the changes in the room- and low-temperature magnetism of volcanic lake sediments, which would extend our knowledge of MTB magnetism contribution to volcanic ecosystems.
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Affiliation(s)
- Weijia Xing
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Huixin Hu
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Yu Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Dan Zhao
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Hong Pan
- Institute of Volcano and Spring, Heilongjiang Academy of Science, Wudalianchi 164155, PR China
| | - Shuang Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China.
| | - Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China; College of Food Science, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China.
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9
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Callefo F, Maldanis L, Teixeira VC, Abans RADO, Monfredini T, Rodrigues F, Galante D. Evaluating Biogenicity on the Geological Record With Synchrotron-Based Techniques. Front Microbiol 2019; 10:2358. [PMID: 31681221 PMCID: PMC6798071 DOI: 10.3389/fmicb.2019.02358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 09/27/2019] [Indexed: 11/17/2022] Open
Abstract
The biogenicity problem of geological materials is one of the most challenging ones in the field of paleo and astrobiology. As one goes deeper in time, the traces of life become feeble and ambiguous, blending with the surrounding geology. Well-preserved metasedimentary rocks from the Archaean are relatively rare, and in very few cases contain structures resembling biological traces or fossils. These putative biosignatures have been studied for decades and many biogenicity criteria have been developed, but there is still no consensus for many of the proposed structures. Synchrotron-based techniques, especially on new generation sources, have the potential for contributing to this field of research, providing high sensitivity and resolution that can be advantageous for different scientific problems. Exploring the X-ray and matter interactions on a range of geological materials can provide insights on morphology, elemental composition, oxidation states, crystalline structure, magnetic properties, and others, which can measurably contribute to the investigation of biogenicity of putative biosignatures. Here, we provide an overview of selected synchrotron-based techniques that have the potential to be applied in different types of questions on the study of biosignatures preserved in the geological record. The development of 3rd and recently 4th generation synchrotron sources will favor a deeper understanding of the earliest records of life on Earth and also bring up potential analytical approaches to be applied for the search of biosignatures in meteorites and samples returned from Mars in the near future.
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Affiliation(s)
- Flavia Callefo
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Lara Maldanis
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
- Institute of Physics of São Carlos, University of São Paulo, São Paulo, Brazil
| | - Verônica C. Teixeira
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Rodrigo Adrián de Oliveira Abans
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
- Interunits Graduate Program in Biotechnology, University of São Paulo, São Paulo, Brazil
| | - Thiago Monfredini
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Fabio Rodrigues
- Fundamental Chemistry Department, University of São Paulo, São Paulo, Brazil
| | - Douglas Galante
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
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10
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Marshall SM, Murray ARG, Cronin L. A probabilistic framework for identifying biosignatures using Pathway Complexity. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0342. [PMID: 29133442 PMCID: PMC5686400 DOI: 10.1098/rsta.2016.0342] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/18/2017] [Indexed: 05/18/2023]
Abstract
One thing that discriminates living things from inanimate matter is their ability to generate similarly complex or non-random structures in a large abundance. From DNA sequences to folded protein structures, living cells, microbial communities and multicellular structures, the material configurations in biology can easily be distinguished from non-living material assemblies. Many complex artefacts, from ordinary bioproducts to human tools, though they are not living things, are ultimately produced by biological processes-whether those processes occur at the scale of cells or societies, they are the consequences of living systems. While these objects are not living, they cannot randomly form, as they are the product of a biological organism and hence are either technological or cultural biosignatures. A generalized approach that aims to evaluate complex objects as possible biosignatures could be useful to explore the cosmos for new life forms. However, it is not obvious how it might be possible to create such a self-contained approach. This would require us to prove rigorously that a given artefact is too complex to have formed by chance. In this paper, we present a new type of complexity measure, which we call 'Pathway Complexity', that allows us not only to threshold the abiotic-biotic divide, but also to demonstrate a probabilistic approach based on object abundance and complexity which can be used to unambiguously assign complex objects as biosignatures. We hope that this approach will not only open up the search for biosignatures beyond the Earth, but also allow us to explore the Earth for new types of biology, and to determine when a complex chemical system discovered in the laboratory could be considered alive.This article is part of the themed issue 'Reconceptualizing the origins of life'.
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Affiliation(s)
| | | | - Leroy Cronin
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
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11
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Bedrossian M, Lindensmith C, Nadeau JL. Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds. ASTROBIOLOGY 2017; 17:913-925. [PMID: 28708412 PMCID: PMC5610429 DOI: 10.1089/ast.2016.1616] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/06/2017] [Indexed: 05/20/2023]
Abstract
Detection of extant microbial life on Earth and elsewhere in the Solar System requires the ability to identify and enumerate micrometer-scale, essentially featureless cells. On Earth, bacteria are usually enumerated by culture plating or epifluorescence microscopy. Culture plates require long incubation times and can only count culturable strains, and epifluorescence microscopy requires extensive staining and concentration of the sample and instrumentation that is not readily miniaturized for space. Digital holographic microscopy (DHM) represents an alternative technique with no moving parts and higher throughput than traditional microscopy, making it potentially useful in space for detection of extant microorganisms provided that sufficient numbers of cells can be collected. Because sample collection is expected to be the limiting factor for space missions, especially to outer planets, it is important to quantify the limits of detection of any proposed technique for extant life detection. Here we use both laboratory and field samples to measure the limits of detection of an off-axis digital holographic microscope (DHM). A statistical model is used to estimate any instrument's probability of detection at various bacterial concentrations based on the optical performance characteristics of the instrument, as well as estimate the confidence interval of detection. This statistical model agrees well with the limit of detection of 103 cells/mL that was found experimentally with laboratory samples. In environmental samples, active cells were immediately evident at concentrations of 104 cells/mL. Published estimates of cell densities for Enceladus plumes yield up to 104 cells/mL, which are well within the off-axis DHM's limits of detection to confidence intervals greater than or equal to 95%, assuming sufficient sample volumes can be collected. The quantitative phase imaging provided by DHM allowed minerals to be distinguished from cells. Off-axis DHM's ability for rapid low-level bacterial detection and counting shows its viability as a technique for detection of extant microbial life provided that the cells can be captured intact and delivered to the sample chamber in a sufficient volume of liquid for imaging. Key Words: In situ life detection-Extant microorganisms-Holographic microscopy-Ocean Worlds-Enceladus-Imaging. Astrobiology 17, 913-925.
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Affiliation(s)
- Manuel Bedrossian
- Graduate Aerospace Laboratories (GALCIT) and Medical Engineering, California Institute of Technology, Pasadena, California
| | - Chris Lindensmith
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Jay L. Nadeau
- Graduate Aerospace Laboratories (GALCIT) and Medical Engineering, California Institute of Technology, Pasadena, California
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12
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Vago JL, Westall F. Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover. ASTROBIOLOGY 2017; 17:471-510. [PMID: 31067287 PMCID: PMC5685153 DOI: 10.1089/ast.2016.1533] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 03/05/2017] [Indexed: 05/19/2023]
Abstract
The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information. Key Words: Biosignatures-ExoMars-Landing sites-Mars rover-Search for life. Astrobiology 17, 471-510.
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13
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Yan L, Da H, Zhang S, López VM, Wang W. Bacterial magnetosome and its potential application. Microbiol Res 2017; 203:19-28. [PMID: 28754204 DOI: 10.1016/j.micres.2017.06.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/08/2017] [Accepted: 06/17/2017] [Indexed: 01/01/2023]
Abstract
Bacterial magnetosome, synthetized by magnetosome-producing microorganisms including magnetotactic bacteria (MTB) and some non-magnetotactic bacteria (Non-MTB), is a new type of material comprising magnetic nanocrystals surrounded by a phospholipid bilayer. Because of the special properties such as single magnetic domain, excellent biocompatibility and surface modification, bacterial magnetosome has become an increasingly attractive for researchers in biology, medicine, paleomagnetism, geology and environmental science. This review briefly describes the general feature of magnetosome-producing microorganisms. This article also highlights recent advances in the understanding of the biochemical and magnetic characteristics of bacterial magnetosome, as well as the magnetosome formation mechanism including iron ions uptake, magnetosome membrane formation, biomineralization and magnetosome chain assembly. Finally, this review presents the potential applications of bacterial magnetosome in biomedicine, wastewater treatment, and the significance of mineralization of magnetosome in biology and geology.
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Affiliation(s)
- Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319, PR China.
| | - Huiyun Da
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319, PR China
| | - Shuang Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319, PR China
| | - Viviana Morillo López
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154, USA
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319, PR China
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14
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Zhang H, Menguy N, Wang F, Benzerara K, Leroy E, Liu P, Liu W, Wang C, Pan Y, Chen Z, Li J. Magnetotactic Coccus Strain SHHC-1 Affiliated to Alphaproteobacteria Forms Octahedral Magnetite Magnetosomes. Front Microbiol 2017; 8:969. [PMID: 28611762 PMCID: PMC5447723 DOI: 10.3389/fmicb.2017.00969] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/15/2017] [Indexed: 11/13/2022] Open
Abstract
Magnetotactic bacteria (MTB) are morphologically and phylogenetically diverse prokaryotes. They can form intracellular chain-assembled magnetite (Fe3O4) or greigite (Fe3S4) nanocrystals each enveloped by a lipid bilayer membrane called a magnetosome. Magnetotactic cocci have been found to be the most abundant morphotypes of MTB in various aquatic environments. However, knowledge on magnetosome biomineralization within magnetotactic cocci remains elusive due to small number of strains that have been cultured. By using a coordinated fluorescence and scanning electron microscopy method, we discovered a unique magnetotactic coccus strain (tentatively named SHHC-1) in brackish sediments collected from the estuary of Shihe River in Qinhuangdao city, eastern China. It phylogenetically belongs to the Alphaproteobacteria class. Transmission electron microscopy analyses reveal that SHHC-1 cells formed many magnetite-type magnetosomes organized as two bundles in each cell. Each bundle contains two parallel chains with smaller magnetosomes generally located at the ends of each chain. Unlike most magnetotactic alphaproteobacteria that generally form magnetosomes with uniform crystal morphologies, SHHC-1 magnetosomes display a more diverse variety of crystal morphology even within a single cell. Most particles have rectangular and rhomboidal projections, whilst others are triangular, or irregular. High resolution transmission electron microscopy observations coupled with morphological modeling indicate an idealized model-elongated octahedral crystals, a form composed of eight {111} faces. Furthermore, twins, multiple twins and stack dislocations are frequently observed in the SHHC-1 magnetosomes. This suggests that biomineralization of strain SHHC-1 magnetosome might be less biologically controlled than other magnetotactic alphaproteobacteria. Alternatively, SHHC-1 is more sensitive to the unfavorable environments under which it lives, or a combination of both factors may have controlled the magnetosome biomineralization process within this unique MTB.
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Affiliation(s)
- Heng Zhang
- Department of Life Science and Technology, Heilongjiang Bayi Agricultural UniversityDaqing, China.,Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
| | - Nicolas Menguy
- France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China.,IMPMC, Centre National de la Recherche Scientifique, UMR 7590, Sorbonne Universités, MNHN, UPMC, IRD UMR 206Paris, France
| | - Fuxian Wang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
| | - Karim Benzerara
- IMPMC, Centre National de la Recherche Scientifique, UMR 7590, Sorbonne Universités, MNHN, UPMC, IRD UMR 206Paris, France
| | - Eric Leroy
- France Chimie Me'tallurgique des Terres Rares, ICMPE, UMR 7182, Centre National de la Recherche ScientifiqueThiais, France
| | - Peiyu Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
| | - Wenqi Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
| | - Chunli Wang
- Department of Life Science and Technology, Heilongjiang Bayi Agricultural UniversityDaqing, China
| | - Yongxin Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
| | - Zhibao Chen
- Department of Life Science and Technology, Heilongjiang Bayi Agricultural UniversityDaqing, China
| | - Jinhua Li
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of SciencesBeijing, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China.,France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of SciencesBeijing, China
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15
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Abstract
There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.
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16
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Magnetotactic bacteria from extreme environments. Life (Basel) 2013; 3:295-307. [PMID: 25369742 PMCID: PMC4187138 DOI: 10.3390/life3020295] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 03/13/2013] [Accepted: 03/13/2013] [Indexed: 11/16/2022] Open
Abstract
Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic-anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.
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Yan L, Zhang S, Chen P, Liu H, Yin H, Li H. Magnetotactic bacteria, magnetosomes and their application. Microbiol Res 2012; 167:507-19. [PMID: 22579104 DOI: 10.1016/j.micres.2012.04.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/05/2012] [Accepted: 04/17/2012] [Indexed: 12/15/2022]
Abstract
Magnetotactic bacteria (MTB) are a diverse group of microorganisms with the ability to orient and migrate along geomagnetic field lines. This unique feat is based on specific intracellular organelles, the magnetosomes, which, in most MTB, comprise nanometer-sized, membrane bound crystals of magnetic iron minerals and organized into chains via a dedicated cytoskeleton. Because of the special properties of the magnetosomes, MTB are of great interest for paleomagnetism, environmental magnetism, biomarkers in rocks, magnetic materials and biomineralization in organisms, and bacterial magnetites have been exploited for a variety of applications in modern biological and medical sciences. In this paper, we describe general characteristics of MTB and their magnetic mineral inclusions, but focus mainly on the magnetosome formation and the magnetisms of MTB and bacterial magnetosomes, as well as on the significances and applications of MTB and their intracellular magnetic mineral crystals.
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Affiliation(s)
- Lei Yan
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University-HLBU, Daqing 163319, PR China.
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18
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Abstract
The biological record suggests that life on Earth arose as soon as conditions were favorable, which indicates that life either originated quickly, or arrived from elsewhere to seed Earth. Experimental research under the theme of “astrobiology” has produced data that some view as strong evidence for the second possibility, known as the panspermia hypothesis. While it is not unreasonable to consider the possibility that Earth’s life originated elsewhere and potentially much earlier, we conclude that the current literature offers no definitive evidence to support this hypothesis.
Chladni’s view, that they fall from the skies, pronounced in 1795, was ridiculed by the learned men of the times. (Rachel, 1881) Evidence of life on Mars, even if only in the distant past, would finally answer the age-old question of whether living beings on Earth are alone in the universe. The magnitude of such a discovery is illustrated by President Bill Clinton’s appearance at a 1996 press conference to announce that proof had been found at last. A meteorite chipped from the surface of the Red Planet some 15 million years ago appeared to contain the fossil remains of tiny life-forms that indicated life had once existed on Mars. (Young and Martel, 2010)
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Lefèvre CT, Frankel RB, Pósfai M, Prozorov T, Bazylinski DA. Isolation of obligately alkaliphilic magnetotactic bacteria from extremely alkaline environments. Environ Microbiol 2011; 13:2342-50. [PMID: 21605309 DOI: 10.1111/j.1462-2920.2011.02505.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Large numbers of magnetotactic bacteria were discovered in mud and water samples collected from a number of highly alkaline aquatic environments with pH values of ≈ 9.5. These bacteria were helical in morphology and biomineralized chains of bullet-shaped crystals of magnetite and were present in all the highly alkaline sites sampled. Three strains from different sites were isolated and cultured and grew optimally at pH 9.0-9.5 but not at 8.0 and below, demonstrating that these organisms truly require highly alkaline conditions and are not simply surviving/growing in neutral pH micro-niches in their natural habitats. All strains grew anaerobically through the reduction of sulfate as a terminal electron acceptor and phylogenetic analysis, based on 16S rRNA gene sequences, as well as some physiological features, showed that they could represent strains of Desulfonatronum thiodismutans, a known alkaliphilic bacterium that does not biomineralize magnetosomes. Our results show that some magnetotactic bacteria can be considered extremophilic and greatly extend the known ecology of magnetotactic bacteria and the conditions under which they can biomineralize magnetite. Moreover, our results show that this type of magnetotactic bacterium is common in highly alkaline environments. Our findings also greatly influence the interpretation of the presence of nanometer-sized magnetite crystals, so-called magnetofossils, in highly alkaline environments.
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Affiliation(s)
- Christopher T Lefèvre
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154-4004, USA
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20
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21
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Jimenez-Lopez C, Romanek CS, Bazylinski DA. Magnetite as a prokaryotic biomarker: A review. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jg001152] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Christopher S. Romanek
- NASA Astrobiology Institute and Department of Earth and Environmental Sciences; University of Kentucky; Lexington Kentucky USA
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22
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Cockell CS. Geomicrobiology beyond Earth: microbe-mineral interactions in space exploration and settlement. Trends Microbiol 2010; 18:308-14. [PMID: 20381355 DOI: 10.1016/j.tim.2010.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 03/04/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
Geomicrobiology investigates the interactions of microorganisms with geological substrates, and this branch of microbiology has enormous potential in the exploration and settlement of space. Microorganisms can be used to extract useful elements from extraterrestrial materials for industrial processes or for use as nutrients in life support systems. In addition, microorganisms could be used to create soil from lunar and Martian rocks. Furthermore, understanding the interactions of microorganisms with rocks is essential for identifying mineral biomarkers to be used in the search for life on other planetary bodies. Increasing space exploration activities make geomicrobiology an important applied science beyond Earth.
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24
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Abstract
Magnetosomes are specialized organelles for magnetic navigation that comprise membrane-enveloped, nano-sized crystals of a magnetic iron mineral; they are formed by a diverse group of magnetotactic bacteria (MTB). The synthesis of magnetosomes involves strict genetic control over intracellular differentiation, biomineralization, and their assembly into highly ordered chains. Physicochemical control over biomineralization is achieved by compartmentalization within vesicles of the magnetosome membrane, which is a phospholipid bilayer associated with a specific set of proteins that have known or suspected functions in vesicle formation, iron transport, control of crystallization, and arrangement of magnetite particles. Magnetosome formation is genetically complex, and relevant genes are predominantly located in several operons within a conserved genomic magnetosome island that has been likely transferred horizontally and subsequently adapted between diverse MTB during evolution. This review summarizes the recent progress in our understanding of magnetobacterial cell biology, genomics, and the genetic control of magnetosome formation and magnetotaxis.
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Affiliation(s)
- Christian Jogler
- Department of Biology I, LMU Biozentrum, Ludwig-Maximilians-Universität München, Planegg-Martinsried 82152, Germany.
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25
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Xie J, Chen K, Chen X. Production, Modification and Bio-Applications of Magnetic Nanoparticles Gestated by Magnetotactic Bacteria. NANO RESEARCH 2009; 2:261-278. [PMID: 20631916 PMCID: PMC2902887 DOI: 10.1007/s12274-009-9025-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 01/20/2009] [Accepted: 01/21/2009] [Indexed: 05/25/2023]
Abstract
Magnetotactic bacteria (MTB) were first discovered by Richard P. Blakemore in 1975, and this led to the discovery of a wide collection of microorganisms with similar features i.e., the ability to internalize Fe and convert it into magnetic nanoparticles, in the form of either magnetite (Fe(3)O(4)) or greigite (Fe(3)S(4)). Studies showed that these particles are highly crystalline, monodisperse, bioengineerable and have high magnetism that is comparable to those made by advanced synthetic methods, making them candidate materials for a broad range of bio-applications. In this review article, the history of the discovery of MTB and subsequent efforts to elucidate the mechanisms behind the magnetosome formation are briefly covered. The focus is on how to utilize the knowledge gained from fundamental studies to fabricate functional MTB nanoparticles (MTB-NPs) that are capable of tackling real biomedical problems.
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Affiliation(s)
- Jin Xie
- Department of Radiology, Bio-X Program, Stanford University School of Medicine, Stanford, CA 94305-5484, USA
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26
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Keim CN, Lins U, Farina M. Manganese in biogenic magnetite crystals from magnetotactic bacteria. FEMS Microbiol Lett 2009; 292:250-3. [DOI: 10.1111/j.1574-6968.2009.01499.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Schüler D. Genetics and cell biology of magnetosome formation in magnetotactic bacteria. FEMS Microbiol Rev 2008; 32:654-72. [PMID: 18537832 DOI: 10.1111/j.1574-6976.2008.00116.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The ability of magnetotactic bacteria (MTB) to orient in magnetic fields is based on the synthesis of magnetosomes, which are unique prokaryotic organelles comprising membrane-enveloped, nano-sized crystals of a magnetic iron mineral that are aligned in well-ordered intracellular chains. Magnetosome crystals have species-specific morphologies, sizes, and arrangements. The magnetosome membrane, which originates from the cytoplasmic membrane by invagination, represents a distinct subcellular compartment and has a unique biochemical composition. The roughly 20 magnetosome-specific proteins have functions in vesicle formation, magnetosomal iron transport, and the control of crystallization and intracellular arrangement of magnetite particles. The assembly of magnetosome chains is under genetic control and involves the action of an acidic protein that links magnetosomes to a novel cytoskeletal structure, presumably formed by a specific actin-like protein. A total of 28 conserved genes present in various magnetic bacteria were identified to be specifically associated with the magnetotactic phenotype, most of which are located in the genomic magnetosome island. The unique properties of magnetosomes attracted broad interdisciplinary interest, and MTB have recently emerged as a model to study prokaryotic organelle formation and evolution.
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Affiliation(s)
- Dirk Schüler
- Faculty of Biology, Microbiology, Ludwig Maximilians University, München, Germany.
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28
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Bazylinski DA, Schübbe S. Controlled biomineralization by and applications of magnetotactic bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2007; 62:21-62. [PMID: 17869601 DOI: 10.1016/s0065-2164(07)62002-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, Nevada 89154, USA
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29
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Abstract
A simple apparatus was designed to effectively isolate magnetotactic bacteria from soils or sediments based on their magnetotaxis. Through a series of processes including sample incubation, MTB harvesting, isolation, purification and identification, several strains of bacteria were isolated from the samples successfully. By Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Analysis (EDXA), these bacteria were certificated to be magnetotactic bacteria. The phylogenetic relationship between the isolated magnetic strains and some known magnetotactic bacteria was inferred by the construction of phylogenetic tree based on 16SrDNA sequences. This apparatus has been proven to have the advantages of being inexpensive, simple to assemble, easy to perform and highly efficient to isolate novel magnetotactic bacteria. The research indicated that the combined approach of harvesting MTB by home-made apparatus and the method of plate colony isolation could purify and isolate magnetotactic bacteria effectively.
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30
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Toporski J, Steele A. Observations from a 4-year contamination study of a sample depth profile through Martian meteorite Nakhla. ASTROBIOLOGY 2007; 7:389-401. [PMID: 17480167 DOI: 10.1089/ast.2006.0009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Morphological, compositional, and biological evidence indicates the presence of numerous well-developed microbial hyphae structures distributed within four different sample splits of the Nakhla meteorite obtained from the British Museum (allocation BM1913,25). By examining depth profiles of the sample splits over time, morphological changes displayed by the structures were documented, as well as changes in their distribution on the samples, observations that indicate growth, decay, and reproduction of individual microorganisms. Biological staining with DNA-specific molecular dyes followed by epifluorescence microscopy showed that the hyphae structures contain DNA. Our observations demonstrate the potential of microbial interaction with extraterrestrial materials, emphasize the need for rapid investigation of Mars return samples as well as any other returned or impactor-delivered extraterrestrial materials, and suggest the identification of appropriate storage conditions that should be followed immediately after samples retrieved from the field are received by a handling/curation facility. The observations are further relevant in planetary protection considerations as they demonstrate that microorganisms may endure and reproduce in extraterrestrial materials over long (at least 4 years) time spans. The combination of microscopy images coupled with compositional and molecular staining techniques is proposed as a valid method for detection of life forms in martian materials as a first-order assessment. Time-resolved in situ observations further allow observation of possible (bio)dynamics within the system.
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Affiliation(s)
- Jan Toporski
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, USA.
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31
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Kempf MJ, Chen F, Kern R, Venkateswaran K. Recurrent isolation of hydrogen peroxide-resistant spores of Bacillus pumilus from a spacecraft assembly facility. ASTROBIOLOGY 2005; 5:391-405. [PMID: 15941382 DOI: 10.1089/ast.2005.5.391] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
While the microbial diversity of a spacecraft assembly facility at the Jet Propulsion Laboratory (Pasadena, CA) was being monitored, H2O2-resistant bacterial strains were repeatedly isolated from various surface locations. H2O2 is a possible sterilant for spacecraft hardware because it is a low-temperature process and compatible with various modern-day spacecraft materials, electronics, and components. Both conventional biochemical testing and molecular analyses identified these strains as Bacillus pumilus. This Bacillus species was found in both unclassified (entrance floors, anteroom, and air-lock) and classified (floors, cabinet tops, and air) locations. Both vegetative cells and spores of several B. pumilus isolates were exposed to 5% liquid H2O2 for 60 min. Spores of each strain exhibited higher resistance than their respective vegetative cells to liquid H2O2. Results indicate that the H2O2 resistance observed in both vegetative cells and spores is strain-specific, as certain B. pumilus strains were two to three times more resistant than a standard Bacillus subtilis dosimetry strain. An example of this trend was observed when the type strain of B. pumilus, ATCC 7061, proved sensitive, whereas several environmental strains exhibited varying degrees of resistance, to H2O2. Repeated isolation of H2O2-resistant strains of B. pumilus in a clean-room is a concern because their persistence might potentially compromise life-detection missions, which have very strict cleanliness and sterility requirements for spacecraft hardware.
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Affiliation(s)
- Michael J Kempf
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
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32
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Affiliation(s)
- Dennis A Bazylinski
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
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33
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Dubbels BL, DiSpirito AA, Morton JD, Semrau JD, Neto JNE, Bazylinski DA. Evidence for a copper-dependent iron transport system in the marine, magnetotactic bacterium strain MV-1. Microbiology (Reading) 2004; 150:2931-2945. [PMID: 15347752 DOI: 10.1099/mic.0.27233-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells of the magnetotactic marine vibrio, strain MV-1, produce magnetite-containing magnetosomes when grown anaerobically or microaerobically. Stable, spontaneous, non-magnetotactic mutants were regularly observed when cells of MV-1 were cultured on solid media incubated under anaerobic or microaerobic conditions. Randomly amplified polymorphic DNA analysis showed that these mutants are not all genetically identical. Cellular iron content of one non-magnetotactic mutant strain, designated MV-1nm1, grown anaerobically, was ∼20- to 80-fold less than the iron content of wild-type (wt) MV-1 for the same iron concentrations, indicating that MV-1nm1 is deficient in some form of iron uptake. Comparative protein profiles of the two strains showed that MV-1nm1 did not produce several proteins produced by wt MV-1. To understand the potential roles of these proteins in iron transport better, one of these proteins was purified and characterized. This protein, a homodimer with an apparent subunit mass of about 19 kDa, was an iron-regulated, periplasmic protein (p19). Two potential ‘copper-handling’ motifs (MXM/MX2M) are present in the amino acid sequence of p19, and the native protein binds copper in a 1 : 1 ratio. The structural gene for p19,chpA(copperhandlingprotein) and two other putative genes upstream ofchpAwere cloned and sequenced. These putative genes encode a protein similar to the iron permease, Ftr1, from the yeastSaccharomyces cerevisiae, and a ferredoxin-like protein of unknown function. A periplasmic, copper-containing, iron(II) oxidase was also purified from wt MV-1 and MV-1nm1. This enzyme, like p19, was regulated by media iron concentration and contained four copper atoms per molecule of enzyme. It is hypothesized that ChpA, the iron permease and the iron(II) oxidase might have analogous functions for the three components of theS. cerevisiaecopper-dependent high-affinity iron uptake system (Ctr1, Ftr1 and Fet3, respectively), and that strain MV-1 may have a similar iron uptake system. However, iron(II) oxidase purified from both wt MV-1 and MV-1nm1 displayed comparable iron oxidase activities using O2as the electron acceptor, indicating that ChpA does not supply the multi-copper iron(II) oxidase with copper.
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Affiliation(s)
- Bradley L Dubbels
- Graduate Program in Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Alan A DiSpirito
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - John D Morton
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - J N E Neto
- Graduate Program in Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Dennis A Bazylinski
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
- Graduate Program in Microbiology, Iowa State University, Ames, IA 50011, USA
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34
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Grünberg K, Müller EC, Otto A, Reszka R, Linder D, Kube M, Reinhardt R, Schüler D. Biochemical and proteomic analysis of the magnetosome membrane in Magnetospirillum gryphiswaldense. Appl Environ Microbiol 2004; 70:1040-50. [PMID: 14766587 PMCID: PMC348919 DOI: 10.1128/aem.70.2.1040-1050.2004] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed the biochemical composition of the magnetosome membrane (MM) in Magnetospirillum gryphiswaldense. Isolated magnetosomes were associated with phospholipids and fatty acids which were similar to phospholipids and fatty acids from other subcellular compartments (i.e., outer and cytoplasmic membranes) but were present in different proportions. The binding characteristics of MM-associated proteins were studied by selective solubilization and limited proteolysis. The MM-associated proteins were further analyzed by various proteomic approaches, including one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Edman and mass spectrometric (electrospray ionization-mass spectrometry-mass spectrometry) sequencing, as well as capillary liquid chromatography-mass spectrometry-mass spectrometry of total tryptic digests of the MM. At least 18 proteins were found to constitute the magnetosome subproteome, and most of these proteins are novel for M. gryphiswaldense. Except for MM22 and Mms16, all bona fide MM proteins (MMPs) were encoded by open reading frames in the mamAB, mamDC, and mms6 clusters in the previously identified putative magnetosome island. Eight of the MMPs display homology to known families, and some of them occur in the MM in multiple homologues. Ten of the MMPs have no known homologues in nonmagnetic organisms and thus represent novel, magnetotactic bacterium-specific protein families. Several MMPs display repetitive or highly acidic sequence patterns, which are known from other biomineralizing systems and thus may have relevance for magnetite formation.
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Affiliation(s)
- Karen Grünberg
- Max-Planck-Institut für Marine Mikrobiologie, 28359 Bremen, Germany
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Weiss BP, Kim SS, Kirschvink JL, Kopp RE, Sankaran M, Kobayashi A, Komeili A. Magnetic tests for magnetosome chains in Martian meteorite ALH84001. Proc Natl Acad Sci U S A 2004; 101:8281-4. [PMID: 15155900 PMCID: PMC420385 DOI: 10.1073/pnas.0402292101] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Indexed: 11/18/2022] Open
Abstract
Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains. Alignment of magnetosomes in chains is perhaps the most distinctive of the six crystallographic properties thought to be collectively unique to magnetofossils. Here we use three rock magnetic techniques, low-temperature cycling, the Moskowitz test, and ferromagnetic resonance, to sense the bulk composition and crystallography of millions of ALH84001 magnetite crystals. The magnetic data demonstrate that although the magnetite is unusually pure and fine-grained in a manner similar to terrestrial magnetofossils, most or all of the crystals are not arranged in chains.
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Affiliation(s)
- Benjamin P Weiss
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
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Link L, Sawyer J, Venkateswaran K, Nicholson W. Extreme spore UV resistance of Bacillus pumilus isolates obtained from an ultraclean Spacecraft Assembly Facility. MICROBIAL ECOLOGY 2004; 47:159-63. [PMID: 14502417 DOI: 10.1007/s00248-003-1029-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Accepted: 06/23/2003] [Indexed: 05/24/2023]
Abstract
Recent environmental microbial sampling of the ultraclean Spacecraft Assembly Facility at NASA Jet Propulsion Laboratory (JPL-SAF) identified spores of Bacillus pumilus as major culturable bacterial contaminants found on and around spacecraft. As part of an effort to assess the efficacy of various spacecraft sterilants, purified spores of 10 JPL-SAF B. pumilus isolates were subjected to 254-nm UV and their UV resistance was compared to spores of standard B. subtilis biodosimetry strains. Spores of six of the 10 JPL-SAF isolates were significantly more resistant to UV than the B. subtilis biodosimetry strain, and one of the JPL-SAF isolates, B. pumilus SAFR-032, exhibited the highest degree of spore UV resistance observed by any Bacillus spp. encountered to date.
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Affiliation(s)
- L Link
- Department of Veterinary Science and Microbiology, University of Arizona, Tucson, AZ 85721, USA
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Schübbe S, Kube M, Scheffel A, Wawer C, Heyen U, Meyerdierks A, Madkour MH, Mayer F, Reinhardt R, Schüler D. Characterization of a spontaneous nonmagnetic mutant of Magnetospirillum gryphiswaldense reveals a large deletion comprising a putative magnetosome island. J Bacteriol 2003; 185:5779-90. [PMID: 13129949 PMCID: PMC193972 DOI: 10.1128/jb.185.19.5779-5790.2003] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Frequent spontaneous loss of the magnetic phenotype was observed in stationary-phase cultures of the magnetotactic bacterium Magnetospirillum gryphiswaldense MSR-1. A nonmagnetic mutant, designated strain MSR-1B, was isolated and characterized. The mutant lacked any structures resembling magnetosome crystals as well as internal membrane vesicles. The growth of strain MSR-1B was impaired under all growth conditions tested, and the uptake and accumulation of iron were drastically reduced under iron-replete conditions. A large chromosomal deletion of approximately 80 kb was identified in strain MSR-1B, which comprised both the entire mamAB and mamDC clusters as well as further putative operons encoding a number of magnetosome-associated proteins. A bacterial artificial chromosome clone partially covering the deleted region was isolated from the genomic library of wild-type M. gryphiswaldense. Sequence analysis of this fragment revealed that all previously identified mam genes were closely linked with genes encoding other magnetosome-associated proteins within less than 35 kb. In addition, this region was remarkably rich in insertion elements and harbored a considerable number of unknown gene families which appeared to be specific for magnetotactic bacteria. Overall, these findings suggest the existence of a putative large magnetosome island in M. gryphiswaldense and other magnetotactic bacteria.
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Affiliation(s)
- Sabrina Schübbe
- Max-Planck-Institut für Marine Mikrobiologie, 28359 Bremen, Germany
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Abstract
What makes a heavy metal resistant bacterium heavy metal resistant? The mechanisms of action, physiological functions, and distribution of metal-exporting proteins are outlined, namely: CBA efflux pumps driven by proteins of the resistance-nodulation-cell division superfamily, P-type ATPases, cation diffusion facilitator and chromate proteins, NreB- and CnrT-like resistance factors. The complement of efflux systems of 63 sequenced prokaryotes was compared with that of the heavy metal resistant bacterium Ralstonia metallidurans. This comparison shows that heavy metal resistance is the result of multiple layers of resistance systems with overlapping substrate specificities, but unique functions. Some of these systems are widespread and serve in the basic defense of the cell against superfluous heavy metals, but some are highly specialized and occur only in a few bacteria. Possession of the latter systems makes a bacterium heavy metal resistant.
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Affiliation(s)
- Dietrich H Nies
- Institute of Microbiology, Molecular Microbiology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06099 Halle/Saale, Germany.
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Kazmierczak J, Kempe S. Modern terrestrial analogues for the carbonate globules in Martian meteorite ALH84001. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2003; 90:167-72. [PMID: 12712250 DOI: 10.1007/s00114-003-0411-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Accepted: 02/20/2003] [Indexed: 10/25/2022]
Abstract
Modern carbonate globules, located in cracks of submerged volcanic rocks and in calcareous pinnacles in alkaline (sodic) Lake Van, Turkey, appear to be analogues for the approximately 3.9 billion-year-old carbonate globules in Martian meteorite ALH84001. These terrestrial globules have similar diameters and are chemically and mineralogically zoned. Furthermore, they display surface and etching structures similar to those described from ALH84001, which were interpreted as fossilized microbial forms. These terrestrial carbonates formed at low temperatures where Ca-rich groundwaters enter the lake. Chemical, mineralogical, microbiological, and biomolecular methods were used in an attempt to decipher the process responsible for the genesis of these structures. Although the exact mode of formation of Lake Van carbonates remains an enigma, their similarity to the Martian globules indicates that the ALH84001 carbonates may have formed in similar setting on ancient Mars.
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Affiliation(s)
- Józef Kazmierczak
- Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00818 Warsaw, Poland.
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McKay CP, Friedmann EI, Frankel RB, Bazylinski DA. Magnetotactic bacteria on Earth and on Mars. ASTROBIOLOGY 2003; 3:263-270. [PMID: 14577877 DOI: 10.1089/153110703769016361] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin.
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Affiliation(s)
- Christopher P McKay
- Space Science Division, NASA Ames Research Center, Moffett Field, California 94035, USA.
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Benardini JN, Sawyer J, Venkateswaran K, Nicholson WL. Spore UV and acceleration resistance of endolithic Bacillus pumilus and Bacillus subtilis isolates obtained from Sonoran desert basalt: implications for lithopanspermia. ASTROBIOLOGY 2003; 3:709-717. [PMID: 14987476 DOI: 10.1089/153110703322736033] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bacterial spores have been used as model systems for studying the theory of interplanetary transport of life by natural processes such as asteroidal or cometary impacts (i.e., lithopanspermia). Because current spallation theory predicts that near-surface rocks are ideal candidates for planetary ejection and surface basalts are widely distributed throughout the rocky planets, we isolated spore-forming bacteria from the interior of near-subsurface basalt rocks collected in the Sonoran desert near Tucson, Arizona. Spores were found to inhabit basalt at very low concentrations (</=28 colony-forming units/g) in these samples. Six isolates identified as being most closely related to Bacillus pumilus and one Bacillus subtilis isolate were recovered from near-subsurface basalt samples. Populations of purified spores prepared from the isolated strains were subjected to 254-nm UV and ballistics tests in order to assess their resistance to UV radiation and to extreme acceleration shock, two proposed lethal factors for spores during interplanetary transfer. Specific natural isolates of B. pumilus were found to be substantially more resistant to UV and extreme acceleration than were reference laboratory strains of B. subtilis, the benchmark organism, suggesting that spores of environmental B. pumilus isolates may be more likely to survive the rigors of interplanetary transfer.
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Affiliation(s)
- James N Benardini
- Department of Veterinary Science and Microbiology, University of Arizona, Tucson, Arizona, USA
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