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Muratov E, Rosenbaum FP, Fuchs FM, Ulrich NJ, Awakowicz P, Setlow P, Moeller R. Multifactorial resistance of Bacillus subtilis spores to low-pressure plasma sterilization. Appl Environ Microbiol 2024; 90:e0132923. [PMID: 38112445 PMCID: PMC10807416 DOI: 10.1128/aem.01329-23] [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: 08/04/2023] [Accepted: 11/05/2023] [Indexed: 12/21/2023] Open
Abstract
Common sterilization techniques for labile and sensitive materials have far-reaching applications in medical, pharmaceutical, and industrial fields. Heat inactivation, chemical treatment, and radiation are established methods to inactivate microorganisms, but pose a threat to humans and the environment and can damage susceptible materials or products. Recent studies have demonstrated that cold low-pressure plasma (LPP) treatment is an efficient alternative to common sterilization methods, as LPP's levels of radicals, ions, (V)UV-radiation, and exposure to an electromagnetic field can be modulated using different process gases, such as oxygen, nitrogen, argon, or synthetic (ambient) air. To further investigate the effects of LPP, spores of the Gram-positive model organism Bacillus subtilis were tested for their LPP susceptibility including wild-type spores and isogenic spores lacking DNA-repair mechanisms such as non-homologous end-joining (NHEJ) or abasic endonucleases, and protective proteins like α/β-type small acid-soluble spore proteins (SASP), coat proteins, and catalase. These studies aimed to learn how spores resist LPP damage by examining the roles of key spore proteins and DNA-repair mechanisms. As expected, LPP treatment decreased spore survival, and survival after potential DNA damage generated by LPP involved efficient DNA repair following spore germination, spore DNA protection by α/β-type SASP, and catalase breakdown of hydrogen peroxide that can generate oxygen radicals. Depending on the LPP composition and treatment time, LPP treatment offers another method to efficiently inactivate spore-forming bacteria.IMPORTANCESurface-associated contamination by endospore-forming bacteria poses a major challenge in sterilization, since the omnipresence of these highly resistant spores throughout nature makes contamination unavoidable, especially in unprocessed foods. Common bactericidal agents such as heat, UV and γ radiation, and toxic chemicals such as strong oxidizers: (i) are often not sufficient to completely inactivate spores; (ii) can pose risks to the applicant; or (iii) can cause unintended damage to the materials to be sterilized. Cold low-pressure plasma (LPP) has been proposed as an additional method for spore eradication. However, efficient use of LPP in decontamination requires understanding of spores' mechanisms of resistance to and protection against LPP.
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Affiliation(s)
- Erika Muratov
- Radiation Biology Department, Aerospace Microbiology, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), Cologne, Germany
| | - Florian P. Rosenbaum
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt, Germany
| | - Felix M. Fuchs
- Applied Electrodynamics and Plasma Technology, Biomedical Applications of Plasma Technology, Ruhr University Bochum, Bochum, Germany
| | - Nikea J. Ulrich
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Peter Awakowicz
- Applied Electrodynamics and Plasma Technology, Biomedical Applications of Plasma Technology, Ruhr University Bochum, Bochum, Germany
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Ralf Moeller
- Radiation Biology Department, Aerospace Microbiology, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), Cologne, Germany
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Idris AL, Li W, Huang F, Lin F, Guan X, Huang T. Impacts of UV radiation on Bacillus biocontrol agents and their resistance mechanisms. World J Microbiol Biotechnol 2024; 40:58. [PMID: 38165488 DOI: 10.1007/s11274-023-03856-1] [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: 10/05/2023] [Accepted: 11/24/2023] [Indexed: 01/03/2024]
Abstract
Bacillus biocontrol agent(s) BCA(s) such as Bacillus cereus, Bacillus thuringiensis and Bacillus subtilis have been widely applied to control insects' pests of plants and pathogenic microbes, improve plant growth, and facilitate their resistance to environmental stresses. In the last decade, researchers have shown that, the application of Bacillus biocontrol agent(s) BCA(s) optimized agricultural production yield, and reduced disease risks in some crops. However, these bacteria encountered various abiotic stresses, among which ultraviolet (UV) radiation severely decrease their efficiency. Researchers have identified several strategies by which Bacillus biocontrol agents resist the negative effects of UV radiation, including transcriptional response, UV mutagenesis, biochemical and artificial means (addition of protective agents). These strategies are governed by distinct pathways, triggered by UV radiation. Herein, the impact of UV radiation on Bacillus biocontrol agent(s) BCA(s) and their mechanisms of resistance were discussed.
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Affiliation(s)
- Aisha Lawan Idris
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenting Li
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Fugui Huang
- Fujian Polytechnic of Information Technology, Fuzhou, 350003, China
| | - Fuyong Lin
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tianpei Huang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Migration of surface-associated microbial communities in spaceflight habitats. Biofilm 2023; 5:100109. [PMID: 36909662 PMCID: PMC9999172 DOI: 10.1016/j.bioflm.2023.100109] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/05/2023] [Accepted: 02/17/2023] [Indexed: 02/26/2023] Open
Abstract
Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.
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Muñoz-Hisado V, Ruiz-Blas F, Sobrado JM, Garcia-Lopez E, Martinez-Alonso E, Alcázar A, Cid C. Bacterial molecular machinery in the Martian cryosphere conditions. Front Microbiol 2023; 14:1176582. [PMID: 37840745 PMCID: PMC10569478 DOI: 10.3389/fmicb.2023.1176582] [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: 02/28/2023] [Accepted: 07/11/2023] [Indexed: 10/17/2023] Open
Abstract
The exploration of Mars is one of the main objectives of space missions since the red planet is considered to be, or was in the past, potentially habitable. Although the surface of Mars is now dry and arid, abundant research suggests that water covered Mars billions of years ago. Recently, the existence of liquid water in subglacial lakes has been postulated below the South pole of Mars. Until now, experiments have been carried out on the survival of microorganisms in Martian surface conditions, but it remains unknown how their adaptation mechanisms would be in the Martian cryosphere. In this work, two bacterial species (Bacillus subtilis and Curtobacterium flacumfaciens) were subjected to a simulated Martian environment during 24 h using a planetary chamber. Afterward, the molecular machinery of both species was studied to investigate how they had been modified. Proteomes, the entire set of proteins expressed by each bacterium under Earth (named standard) conditions and Martian conditions, were compared using proteomic techniques. To establish this evaluation, both the expression levels of each protein, and the variation in their distribution within the different functional categories were considered. The results showed that these bacterial species followed a different strategy. The Bacillus subtilis resistance approach consisted of improving its stress response, membrane bioenergetics, degradation of biomolecules; and to a lesser extent, increasing its mobility and the formation of biofilms or resistance endospores. On the contrary, enduring strategy of Curtobacterium flacumfaciens comprised of strengthening the cell envelope, trying to protect cells from the extracellular environment. These results are especially important due to their implications for planetary protection, missions to Mars and sample return since contamination by microorganisms would invalidate the results of these investigations.
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Affiliation(s)
| | - Fátima Ruiz-Blas
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, Potsdam, Germany
| | | | | | - Emma Martinez-Alonso
- Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
| | - Alberto Alcázar
- Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
| | - Cristina Cid
- Centro de Astrobiologia (CAB), CSIC-INTA, Madrid, Spain
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Isticato R. Bacterial Spore-Based Delivery System: 20 Years of a Versatile Approach for Innovative Vaccines. Biomolecules 2023; 13:947. [PMID: 37371527 DOI: 10.3390/biom13060947] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/25/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Mucosal vaccines offer several advantages over injectable conventional vaccines, such as the induction of adaptive immunity, with secretory IgA production at the entry site of most pathogens, and needle-less vaccinations. Despite their potential, only a few mucosal vaccines are currently used. Developing new effective mucosal vaccines strongly relies on identifying innovative antigens, efficient adjuvants, and delivery systems. Several approaches based on phages, bacteria, or nanoparticles have been proposed to deliver antigens to mucosal surfaces. Bacterial spores have also been considered antigen vehicles, and various antigens have been successfully exposed on their surface. Due to their peculiar structure, spores conjugate the advantages of live microorganisms with synthetic nanoparticles. When mucosally administered, spores expressing antigens have been shown to induce antigen-specific, protective immune responses. This review accounts for recent progress in the formulation of spore-based mucosal vaccines, describing a spore's structure, specifically the spore surface, and the diverse approaches developed to improve its efficiency as a vehicle for heterologous antigen presentation.
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Affiliation(s)
- Rachele Isticato
- Department of Biology, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia 4, 80126 Naples, Italy
- Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology (BAT Center), 80055 Naples, Italy
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Schultz J, Modolon F, Peixoto RS, Rosado AS. Shedding light on the composition of extreme microbial dark matter: alternative approaches for culturing extremophiles. Front Microbiol 2023; 14:1167718. [PMID: 37333658 PMCID: PMC10272570 DOI: 10.3389/fmicb.2023.1167718] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/09/2023] [Indexed: 06/20/2023] Open
Abstract
More than 20,000 species of prokaryotes (less than 1% of the estimated number of Earth's microbial species) have been described thus far. However, the vast majority of microbes that inhabit extreme environments remain uncultured and this group is termed "microbial dark matter." Little is known regarding the ecological functions and biotechnological potential of these underexplored extremophiles, thus representing a vast untapped and uncharacterized biological resource. Advances in microbial cultivation approaches are key for a detailed and comprehensive characterization of the roles of these microbes in shaping the environment and, ultimately, for their biotechnological exploitation, such as for extremophile-derived bioproducts (extremozymes, secondary metabolites, CRISPR Cas systems, and pigments, among others), astrobiology, and space exploration. Additional efforts to enhance culturable diversity are required due to the challenges imposed by extreme culturing and plating conditions. In this review, we summarize methods and technologies used to recover the microbial diversity of extreme environments, while discussing the advantages and disadvantages associated with each of these approaches. Additionally, this review describes alternative culturing strategies to retrieve novel taxa with their unknown genes, metabolisms, and ecological roles, with the ultimate goal of increasing the yields of more efficient bio-based products. This review thus summarizes the strategies used to unveil the hidden diversity of the microbiome of extreme environments and discusses the directions for future studies of microbial dark matter and its potential applications in biotechnology and astrobiology.
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Affiliation(s)
- Júnia Schultz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Flúvio Modolon
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Silva Peixoto
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Alexandre Soares Rosado
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Deng A, Wang T, Wang J, Li L, Wang X, Liu L, Wen T. Adaptive mechanisms of Bacillus to near space extreme environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 886:163952. [PMID: 37164076 DOI: 10.1016/j.scitotenv.2023.163952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 05/12/2023]
Abstract
Earth's near space is an extreme atmosphere environment with high levels of radiation, low atmospheric pressure and dramatic temperature fluctuations. The region is above the flight altitude of aircraft but below the orbit of satellites, which has special and Mars-like conditions for investigating the survival and evolution of life. Technical limitations including flight devices, payloads and technologies/methodologies hinder microbiological research in near space. In this study, we investigated microbial survival and adaptive strategies in near space using a scientific balloon fight mission and multi-omics analyses. Methods for sample preparation, storage, protector and vessel were optimized to prepare the exposed microbial samples. After 3 h 17 min of exposure at a float altitude of ~32 km, only Bacillus strains were alive with survival efficiencies of 0-10-6. Diverse mutants with significantly altered metabolites were generated, firstly proving that Earth's near space could be used as a new powerful microbial breeding platform. Multi-omics analyses of mutants revealed cascade changes at the genome, transcriptome and proteome levels. In response to environmental stresses, two mutants had similar proteome changes caused by different genomic mutations and mRNA expression levels. Metabolic network analysis combined with proteins' expression levels revealed that metabolic fluxes of EMP, PPP and purine synthesis-related pathways were significantly altered to increase/decrease inosine production. Further analysis showed that proteins related to translation, molecular chaperones, cell wall/membrane, sporulation, DNA replication/repair and anti-oxidation were significantly upregulated, enabling cells to efficiently repair DNA/protein damages and improve viability against environmental stress. Overall, these results revealed genetic and metabolic responses of Bacillus to the harsh conditions in near space, providing a research basis for bacterial adaptive mechanisms in extreme environments.
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Affiliation(s)
- Aihua Deng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Tiantian Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junyue Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lai Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueliang Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Liu
- University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Tingyi Wen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid medical school, University of Chinese Academy of Sciences, Beijing 100049, China; China Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, China.
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Butala M, Dragoš A. Unique relationships between phages and endospore-forming hosts. Trends Microbiol 2022; 31:498-510. [PMID: 36535834 DOI: 10.1016/j.tim.2022.11.009] [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: 09/21/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
As part of their survival strategy under harsh environmental conditions, endospore-forming bacteria can trigger a sporulation developmental program. Although the regulatory cascades that precisely control the transformation of vegetative bacteria into mother cells and resilient spores have been described in detail, less is known about how bacteriophages that prey on endospore-formers exploit sporulation. Herein, we argue that phages infecting these bacteria have evolved several specific molecular mechanisms, not yet known in other bacteria, that manifest from the phage-driven alliance to negative effects on the host. We anticipate that the relationships between phages and endospore-formers outlined here will inspire studies on phage ecology and evolution, and could facilitate important advances in the development of phage therapies against pathogenic spore-formers.
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Affiliation(s)
- Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Anna Dragoš
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
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9
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Bacilli in the International Space Station. Microorganisms 2022; 10:microorganisms10122309. [PMID: 36557562 PMCID: PMC9782108 DOI: 10.3390/microorganisms10122309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Astronauts remote from Earth, not least those who will inhabit the Moon or Mars, are vulnerable to disease due to their reduced immunity, isolation from clinical support, and the disconnect from any buffering capacity provided by the Earth. Here, we explore potential risks for astronaut health, focusing on key aspects of the biology of Bacillus anthracis and other anthrax-like bacilli. We examine aspects of Bacillus cereus group genetics in relation to their evolutionary biology and pathogenicity; a new clade of the Bacillus cereus group, close related to B. anthracis, has colonized the International Space Station (ISS), is still present, and could in theory at least acquire pathogenic plasmids from the other B. cereus group strains. The main finding is that the genomic sequence alignments of the B. cereus group ISS strains revealed a high sequence identity, indicating they originated from the same strain and that a close look to the genetic variations among the strains suggesting they lived, or they are living, in a vegetative form in the ISS enough time to accumulate genetic variations unique for each single strains.
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Liu F, Li J, Zhang T, Chen J, Ho CL. Engineered Spore-Forming Bacillus as a Microbial Vessel for Long-Term DNA Data Storage. ACS Synth Biol 2022; 11:3583-3591. [PMID: 36150134 DOI: 10.1021/acssynbio.2c00291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
DNA data storage technology may supersede conventional chip or magnetic data storage medium, providing long-term stability, high density, and sustainable storage. Due to its error-correcting capability, DNA data stored in living organisms exhibits high fidelity in information replication. Here we report the development of a Bacillus chassis integrated with an inducible artificially assembled bacterial chromosome to facilitate random data access. We generated three sets of data in the form of DNA sequences using a rudimentary coding system accessible by the regulatory promoter. Sporulated Bacillus harboring the genes were used for long-term storage, where viability assays of spores were subjected to harsh environmental stresses to evaluate the data storage stability. The data accuracy remained above 99% after high temperature and oxidative stress treatment, whereas UV irradiation treatment provided above 96% accuracy. The developed Bacillus chassis and artificial chromosome facilitate the long-term storage of larger datum volume by using other DNA digital encoding and decoding programs.
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Affiliation(s)
- Feng Liu
- Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen518055, China
| | - Jiashu Li
- Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen518055, China
| | - Tongzhou Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen518055, China
| | - Jun Chen
- Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen518055, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences, Shenzhen518055, China
| | - Chun Loong Ho
- Department of Biomedical Engineering, Southern University of Science and Technology (SUSTech), Shenzhen518055, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences, Shenzhen518055, China
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11
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Coleine C, Delgado-Baquerizo M. Unearthing terrestrial extreme microbiomes for searching terrestrial-like life in the Solar System. Trends Microbiol 2022; 30:1101-1115. [PMID: 35568658 DOI: 10.1016/j.tim.2022.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/03/2022] [Accepted: 04/11/2022] [Indexed: 01/13/2023]
Abstract
The possibility of life elsewhere in the universe has fascinated humankind for ages. To the best of our knowledge, life, as we know it, is limited to planet Earth; yet current investigation suggests that life might be more common than previously thought. In this review, we explore extreme terrestrial analogue environments in the search for some notable examples of extreme organisms, including overlooked microbial groups such as viruses, fungi, and protists, associated with limits of life on Earth. This knowledge is integral to provide the foundational principles needed to predict what sort of Earth-like organisms we might find in the Solar System and beyond, and to understand the future and origins of life on Earth.
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Affiliation(s)
- Claudia Coleine
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.
| | - Manuel Delgado-Baquerizo
- Laboratorio de Biodiversidad y Funcionamiento Ecosistémico. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Av. Reina Mercedes 10, E-41012, Sevilla, Spain; Unidad Asociada CSIC-UPO (BioFun). Universidad Pablo de Olavide, 41013 Sevilla, Spain.
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12
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Dikec J, Pacheco M, Lavaud M, Winckler P, Perrier-Cornet JM. Uptake of UVc induced photoproducts of dipicolinic acid by Bacillus subtilis spores - Effects on the germination and UVc resistance of the spores. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 236:112569. [PMID: 36152351 DOI: 10.1016/j.jphotobiol.2022.112569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/05/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Dipicolinic acid (DPA) is a specific molecule of bacterial spores which is essential to their resistance to various stresses such as ultraviolet (UV) exposure and to their germination. DPA has a particular photochemistry that remains imperfectly understood. In particular, due to its ability to absorb UVc radiation, it is likely to form in vitro a wide variety of photoproducts (DPAp) of which only about ten have been recently identified. The photochemical reactions resulting in DPAp, especially those inside the spores, are still poorly understood. Only one of these DPAp, which probably acts as a photosensitizer of DNA upon exposure to UVc, has been identified as having an impact on spores. However, as UVc is required to form DPAp, it is difficult to decouple the overall effect of UVc exposure from the possible effects of DPAp alone. In this study, DPAp were artificially introduced into the spores of the FB122 mutant strain of Bacillus subtilis, one that does not produce DPA. These experiments revealed that some DPAp may play a positive role for the spore. These benefits are visible in an improvement in spore germination rate and kinetics, as well as in an increase in their resistance to UVc exposure.
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Affiliation(s)
- J Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Pacheco
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Lavaud
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - P Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - J M Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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13
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Duhamel S, Hamilton CW, Pálsson S, Björnsdóttir SH. Microbial Response to Increased Temperatures Within a Lava-Induced Hydrothermal System in Iceland: An Analogue for the Habitability of Volcanic Terrains on Mars. ASTROBIOLOGY 2022; 22:1176-1198. [PMID: 35920884 DOI: 10.1089/ast.2021.0124] [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: 06/15/2023]
Abstract
Fossil hydrothermal systems on Mars are important exploration targets because they may have once been habitable and could still preserve evidence of microbial life. We investigated microbial communities within an active lava-induced hydrothermal system associated with the 2014-2015 eruption of Holuhraun in Iceland as a Mars analogue. In 2016, the microbial composition in the lava-heated water differed substantially from that of the glacial river and spring water sources that fed into the system. Several taxonomic and metabolic groups were confined to the water emerging from the lava and some showed the highest sequence similarities to subsurface ecosystems, including to the predicted thermophilic and deeply branching Candidatus Acetothermum autotrophicum. Measurements show that the communities were affected by temperature and other environmental factors. In particular, comparing glacial river water incubated in situ (5.7°C, control) with glacial water incubated within a lava-heated stream (17.5°C, warm) showed that microbial abundance, richness, and diversity increased in the warm treatment compared with the control, with the predicted major metabolism shifting from lithotrophy toward organotrophy and possibly phototrophy. In addition, thermophilic bacteria isolated from the lava-heated water and a nearby acidic hydrothermal system included the known endospore-formers Geobacillus stearothermophilus and Paenibacillus cisolokensis as well as a potentially novel taxon within the order Hyphomicrobiales. Similar lava-water interactions on Mars could therefore have generated habitable environments for microbial communities.
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Affiliation(s)
- Solange Duhamel
- Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
| | | | - Snæbjörn Pálsson
- Department of Biology, University of Iceland, Reykjavík, Iceland
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Conservation and Evolution of the Sporulation Gene Set in Diverse Members of the Firmicutes. J Bacteriol 2022; 204:e0007922. [PMID: 35638784 DOI: 10.1128/jb.00079-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The current classification of the phylum Firmicutes (new name, Bacillota) features eight distinct classes, six of which include known spore-forming bacteria. In Bacillus subtilis, sporulation involves up to 500 genes, many of which do not have orthologs in other bacilli and/or clostridia. Previous studies identified about 60 sporulation genes of B. subtilis that were shared by all spore-forming members of the Firmicutes. These genes are referred to as the sporulation core or signature, although many of these are also found in genomes of nonsporeformers. Using an expanded set of 180 firmicute genomes from 160 genera, including 76 spore-forming species, we investigated the conservation of the sporulation genes, in particular seeking to identify lineages that lack some of the genes from the conserved sporulation core. The results of this analysis confirmed that many small acid-soluble spore proteins (SASPs), spore coat proteins, and germination proteins, which were previously characterized in bacilli, are missing in spore-forming members of Clostridia and other classes of Firmicutes. A particularly dramatic loss of sporulation genes was observed in the spore-forming members of the families Planococcaceae and Erysipelotrichaceae. Fifteen species from diverse lineages were found to carry skin (sigK-interrupting) elements of different sizes that all encoded SpoIVCA-like recombinases but did not share any other genes. Phylogenetic trees built from concatenated alignments of sporulation proteins and ribosomal proteins showed similar topology, indicating an early origin and subsequent vertical inheritance of the sporulation genes. IMPORTANCE Many members of the phylum Firmicutes (Bacillota) are capable of producing endospores, which enhance the survival of important Gram-positive pathogens that cause such diseases as anthrax, botulism, colitis, gas gangrene, and tetanus. We show that the core set of sporulation genes, defined previously through genome comparisons of several bacilli and clostridia, is conserved in a wide variety of sporeformers from several distinct lineages of Firmicutes. We also detected widespread loss of sporulation genes in many organisms, particularly within the families Planococcaceae and Erysipelotrichaceae. Members of these families, such as Lysinibacillus sphaericus and Clostridium innocuum, could be excellent model organisms for studying sporulation mechanisms, such as engulfment, formation of the spore coat, and spore germination.
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15
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The rhizosphere of Sulla spinosissima growing in abandoned mining soils is a reservoir of heavy metals tolerant plant growth-promoting rhizobacteria. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2021.102236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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16
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Draft Genome Sequences of Heat Shock-Tolerant Microbes Isolated from a Spacecraft Assembly Facility. Microbiol Resour Announc 2021; 10:e0065321. [PMID: 34498924 PMCID: PMC8428253 DOI: 10.1128/mra.00653-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heat shock-tolerant microorganisms belonging to the orders Bacillales and Micrococcales were isolated from the Spacecraft Assembly Facility at the Jet Propulsion Laboratory, and 63 draft genome sequences were assembled and identified. Further analyses of these genomes can provide insight into methods for preventing forward contamination.
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17
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Goraj W, Szafranek-Nakonieczna A, Grządziel J, Polakowski C, Słowakiewicz M, Zheng Y, Gałązka A, Stępniewska Z, Pytlak A. Microbial Involvement in Carbon Transformation via CH 4 and CO 2 in Saline Sedimentary Pool. BIOLOGY 2021; 10:biology10080792. [PMID: 34440022 PMCID: PMC8389658 DOI: 10.3390/biology10080792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/06/2021] [Accepted: 08/14/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Methane and carbon dioxide are commonly found in the environment and are considered the most important greenhouse gases. Transformation of these gases is in large carried by microorganisms, which occur even in extreme environments. This study presents methane-related biological processes in saline sediments of the Miocene Wieliczka Formation, Poland. Biological activity (carbon dioxide and methane production or methane oxidation), confirmed by stable isotope indices, occurred in all of the studied Wieliczka rocks. CH4-utilizing microbes constituted 0.7–3.6% while methanogens (represented by Methanobacterium) only 0.01–0.5% of taxa present in the Wieliczka Salt Mine rocks. Water activity was the key factor regulating microbial activity in saline subsurface sediments. Generally, CO2 respiration was higher in anaerobic conditions while methanogenic and methanotrophic activities were dependent on the type of rock. Abstract Methane and carbon dioxide are one of the most important greenhouse gases and significant components of the carbon cycle. Biogeochemical methane transformation may occur even in the extreme conditions of deep subsurface ecosystems. This study presents methane-related biological processes in saline sediments of the Miocene Wieliczka Formation, Poland. Rock samples (W2, W3, and W4) differed in lithology (clayey salt with veins of fibrous salt and lenses of gypsum and anhydrite; siltstone and sandstone; siltstone with veins of fibrous salt and lenses of anhydrite) and the accompanying salt type (spiza salts or green salt). Microbial communities present in the Miocene strata were studied using activity measurements and high throughput sequencing. Biological activity (i.e., carbon dioxide and methane production or methane oxidation) occurred in all of the studied clayey salt and siltstone samples but mainly under water-saturated conditions. Microcosm studies performed at elevated moisture created more convenient conditions for the activity of both methanogenic and methanotrophic microorganisms than the intact sediments. This points to the fact that water activity is an important factor regulating microbial activity in saline subsurface sediments. Generally, respiration was higher in anaerobic conditions and ranged from 36 ± 2 (W2200%t.w.c) to 48 ± 4 (W3200%t.w.c) nmol CO2 gdw−1 day−1. Methanogenic activity was the highest in siltstone and sandstone (W3, 0.025 ± 0.018 nmol CH4 gdw−1 day−1), while aerobic methanotrophic activity was the highest in siltstone with salt and anhydrite (W4, 220 ± 66 nmol CH4 gdw−1 day−1). The relative abundance of CH4-utilizing microorganisms (Methylomicrobium, Methylomonas, Methylocystis) constituted 0.7–3.6% of all taxa. Methanogens were represented by Methanobacterium (0.01–0.5%). The methane-related microbes were accompanied by a significant number of unclassified microorganisms (3–64%) and those of the Bacillus genus (4.5–91%). The stable isotope composition of the CO2 and CH4 trapped in the sediments suggests that methane oxidation could have influenced δ13CCH4, especially in W3 and W4.
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Affiliation(s)
- Weronika Goraj
- Institute of Biological Sciences, The John Paul II Catholic University of Lublin, Konstantynów 1 I, 20-708 Lublin, Poland;
- Correspondence: e-mail: ; Tel.: +48-81-454-54-61
| | - Anna Szafranek-Nakonieczna
- Institute of Biological Sciences, The John Paul II Catholic University of Lublin, Konstantynów 1 I, 20-708 Lublin, Poland;
| | - Jarosław Grządziel
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation—State Research Institute (IUNG-PIB), Czartoryskich 8, 24-100 Puławy, Poland; (J.G.); (A.G.)
| | - Cezary Polakowski
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (C.P.); (A.P.)
| | - Mirosław Słowakiewicz
- Faculty of Geology, University of Warsaw, Żwirki i Wigury 93, 02-089 Warszawa, Poland;
- Institute of Geology and Petroleum Technologies, Kazan Federal University, Kremlovskaya 18, 420008 Kazan, Russia
| | - Yanhong Zheng
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an 710069, China;
| | - Anna Gałązka
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation—State Research Institute (IUNG-PIB), Czartoryskich 8, 24-100 Puławy, Poland; (J.G.); (A.G.)
| | - Zofia Stępniewska
- Department of Biochemistry and Environmental Chemistry, The John Paul II Catholic University of Lublin, Konstantynów 1 I, 20-708 Lublin, Poland;
| | - Anna Pytlak
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (C.P.); (A.P.)
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Radchenko MM, Tigunova OO, Zelena LB, Beiko NY, Andriiash HS, Shulga SM. Phylogenetic Analysis of the Bacillus subtilis IFBG MK-2 Strain and Riboflavin Production by Its Induced Clones. CYTOL GENET+ 2021. [DOI: 10.3103/s0095452721020134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Genderjahn S, Lewin S, Horn F, Schleicher AM, Mangelsdorf K, Wagner D. Living Lithic and Sublithic Bacterial Communities in Namibian Drylands. Microorganisms 2021; 9:235. [PMID: 33498742 PMCID: PMC7911874 DOI: 10.3390/microorganisms9020235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/17/2021] [Accepted: 01/20/2021] [Indexed: 12/26/2022] Open
Abstract
Dryland xeric conditions exert a deterministic effect on microbial communities, forcing life into refuge niches. Deposited rocks can form a lithic niche for microorganisms in desert regions. Mineral weathering is a key process in soil formation and the importance of microbial-driven mineral weathering for nutrient extraction is increasingly accepted. Advances in geobiology provide insight into the interactions between microorganisms and minerals that play an important role in weathering processes. In this study, we present the examination of the microbial diversity in dryland rocks from the Tsauchab River banks in Namibia. We paired culture-independent 16S rRNA gene amplicon sequencing with culture-dependent (isolation of bacteria) techniques to assess the community structure and diversity patterns. Bacteria isolated from dryland rocks are typical of xeric environments and are described as being involved in rock weathering processes. For the first time, we extracted extra- and intracellular DNA from rocks to enhance our understanding of potentially rock-weathering microorganisms. We compared the microbial community structure in different rock types (limestone, quartz-rich sandstone and quartz-rich shale) with adjacent soils below the rocks. Our results indicate differences in the living lithic and sublithic microbial communities.
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Affiliation(s)
- Steffi Genderjahn
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Simon Lewin
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Fabian Horn
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Anja M. Schleicher
- GFZ German Research Centre for Geosciences, Section Organic Geochemistry, Telegrafenberg, 14473 Potsdam, Germany;
| | - Kai Mangelsdorf
- GFZ German Research Centre for Geosciences, Section Anorganic Chemistry, Telegrafenberg, 14473 Potsdam, Germany;
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
- Institute of Geosciences, University of Potsdam, 14476 Potsdam, Germany
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20
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Effects of Heavy Ion Particle Irradiation on Spore Germination of Bacillus spp. from Extremely Hot and Cold Environments. Life (Basel) 2020; 10:life10110264. [PMID: 33143156 PMCID: PMC7693761 DOI: 10.3390/life10110264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
Extremophiles are optimal models in experimentally addressing questions about the effects of cosmic radiation on biological systems. The resistance to high charge energy (HZE) particles, and helium (He) ions and iron (Fe) ions (LET at 2.2 and 200 keV/µm, respectively, until 1000 Gy), of spores from two thermophiles, Bacillushorneckiae SBP3 and Bacilluslicheniformis T14, and two psychrotolerants, Bacillus sp. A34 and A43, was investigated. Spores survived He irradiation better, whereas they were more sensitive to Fe irradiation (until 500 Gy), with spores from thermophiles being more resistant to irradiations than psychrotolerants. The survived spores showed different germination kinetics, depending on the type/dose of irradiation and the germinant used. After exposure to He 1000 Gy, D-glucose increased the lag time of thermophilic spores and induced germination of psychrotolerants, whereas L-alanine and L-valine increased the germination efficiency, except alanine for A43. FTIR spectra showed important modifications to the structural components of spores after Fe irradiation at 250 Gy, which could explain the block in spore germination, whereas minor changes were observed after He radiation that could be related to the increased permeability of the inner membranes and alterations of receptor complex structures. Our results give new insights on HZE resistance of extremophiles that are useful in different contexts, including astrobiology.
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Rcheulishvili N, Zhang Y, Papukashvili D, Deng YL. Survey and Evaluation of Spacecraft-Associated Aluminum-Degrading Microbes and Their Rapid Identification Methods. ASTROBIOLOGY 2020; 20:925-934. [PMID: 32783563 DOI: 10.1089/ast.2019.2078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aluminum corrosion has become a major obstacle in spacecraft construction given that aluminum is used extensively throughout the construction process. Despite its many attributes in strength and durability, aluminum is susceptible to corrosion, in particular, corrosion due to microbial contamination. Scientists have encountered a number of problems with microbial aluminum corrosion within spacecraft components. Here, we summarize recent findings with regard to the phenomenon of microbiologically influenced corrosion (MIC) on space stations in the context of microbial strains isolated from the Mir space station (Mir) and the International Space Station (ISS). Given that strains found on spacecraft are of terrestrial origin, an understanding of the contribution of Al-corrosive microbes to corrosion and related risks to space travel and astronaut health is essential for implementation of prevention strategies. Accordingly, an efficient rapid identification method of microbes with the capability to degrade aluminum is proposed. In particular, onboard implementation of a matrix-assisted laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF MS) is addressed. The use of a MALDI-TOF MS on board spacecraft will be crucial to future successes in space travel given that traditional methods of identifying corrosive species are far more time-consuming. Identification of microbes by way of a MALDI-TOF MS may also aid in the study of microbial corrosion and be a valuable asset for MIC prevention.
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Affiliation(s)
- Nino Rcheulishvili
- Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, Beijing Institute of Technology, Beijing, China
| | - Ying Zhang
- Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, Beijing Institute of Technology, Beijing, China
| | - Dimitri Papukashvili
- Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, Beijing Institute of Technology, Beijing, China
| | - Yu-Lin Deng
- Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, Beijing Institute of Technology, Beijing, China
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Christie G, Setlow P. Bacillus spore germination: Knowns, unknowns and what we need to learn. Cell Signal 2020; 74:109729. [PMID: 32721540 DOI: 10.1016/j.cellsig.2020.109729] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023]
Abstract
How might a microbial cell that is entirely metabolically dormant - and which has the ability to remain so for extended periods of time - irreversibly commit itself to resuming vegetative growth within seconds of being exposed to certain amino acids or sugars? That this process takes place in the absence of any detectable ATP or de novo protein synthesis, and relies upon a pre-formed apparatus that is immobilised, respectively, in a semi-crystalline membrane or multi-layered proteinaceous coat, only exacerbates the challenge facing spores of Bacillales species when stimulated to germinate. Whereas the process by which spores are formed in response to nutrient starvation - sporulation - involves the orchestrated interplay between hundreds of distinct proteins, the process by which spores return to life - germination - is a much simpler affair, requiring a handful of receptor and channel proteins complemented with specialized peptidoglycan lysins. Despite this relative simplicity, and research effort spanning many decades, comprehensive understanding of key molecular and biochemical details and, in particular signal transduction mechanisms associated with spore germination, has remained elusive. In this review we provide an up to date overview of the field while identifying what we consider to be the key gaps in knowledge associated with germination of Bacillales spores, suggesting also technical approaches that may provide fresh insight to this unique biological process.
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Affiliation(s)
- Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 OAS, United Kingdom.
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA.
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Abstract
Khadi is a popular traditional alcoholic beverage in rural households in Botswana. The product is produced by fermentation of ripened sun-dried Grewia flava (Malvaceae) fruits supplemented with brown table sugar. Despite its popularity, its growing consumer acceptance, its potential nutritional value, and its contribution to the socio-economic lifestyle of Botswana, the production process remains non-standardized. Non-standardized production processes lead to discrepancies in product quality and safety as well as varying shelf life. Identification of unknown fermentative microorganisms of khadi is an important step towards standardization of its brewing process for entrance into commercial markets. The aim of this study was to isolate and identify bacteria and yeasts responsible for fermentation of khadi. Yeasts and bacteria harbored in 18 khadi samples from 18 brewers in central and northern Botswana were investigated using classic culture-dependent techniques and DNA sequencing methods. Additionally, we used the same techniques to investigate the presence of bacteria and yeasts on six batches of ripened-dried G. flava fruits used for production of the sampled brews. Our results revealed that Saccharomyces cerevisiae closely related to a commercial baker’s yeast strain sold locally was the most predominant yeast species in khadi suggesting a possible non-spontaneous brewing process. However, we also detected diverse non-Saccharomyces yeasts, which are not available commercially in retail shops in Botswana. This suggests that spontaneous fermentation is partially responsible for fermentation of khadi. This study, presenting the first microbiological characterization of a prominent traditional alcoholic beverage in Botswana, is vital for development of starter cultures for the production of a consistent product towards the commercialization of khadi.
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Zhang Y, Huber N, Moeller R, Stülke J, Dubovcova B, Akepsimaidis G, Meneses N, Drissner D, Mathys A. Role of DNA repair in Bacillus subtilis spore resistance to high energy and low energy electron beam treatments. Food Microbiol 2020; 87:103353. [DOI: 10.1016/j.fm.2019.103353] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/04/2019] [Accepted: 10/23/2019] [Indexed: 10/25/2022]
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Tait AW, Gagen EJ, Wilson SA, Tomkins AG, Southam G. Eukaryotic Colonization of Micrometer-Scale Cracks in Rocks: A "Microfluidics" Experiment Using Naturally Weathered Meteorites from the Nullarbor Plain, Australia. ASTROBIOLOGY 2020; 20:364-374. [PMID: 31873039 DOI: 10.1089/ast.2019.2077] [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: 06/10/2023]
Abstract
The advent of microfluidics has revolutionized the way we understand how microorganisms propagate through microporous spaces. Here, we apply this understanding to the study of how endolithic environmental microorganisms colonize the interiors of sterile rock. The substrates used for our study are stony meteorites from the Nullarbor Plain, Australia; a semiarid limestone karst that provides an ideal setting for preserving meteorites. Periodic flooding of the Nullarbor provides a mechanism by which microorganisms and exogenous nutrients may infiltrate meteorites. Our laboratory experiments show that environmental microorganisms reach depths greater than 400 μm by propagating through existing brecciation, passing through cracks no wider than the diameter of a resident cell (i.e., ∼5 μm). Our observations are consistent with the propagation of these eukaryotic cells via growth and cell division rather than motility. The morphology of the microorganisms changed as a result of propagation through micrometer-scale cracks, as has been observed previously for bacteria on microfluidic chips. It has been suggested that meteorites could have served as preferred habitats for microorganisms on ancient Mars. Based on our results, the depths reached by terrestrial microorganisms within meteorites would be sufficient to mitigate against the harmful effects of ionizing radiation, such as UV light, in Earth's deserts and potentially on Mars, if similar processes of microbial colonization had once been active there. Thus, meteorites landing in ancient lakes on Mars, that later dried out, could have been some of the last inhabited locations on the surface, serving as refugia before the planet's surface became inhospitable. Finally, our observations suggest that terrestrial microorganisms can colonize very fine cracks within meteorites (and potentially spaceships and rovers) on unexpectedly short timescales, with important implications for both recognition of extraterrestrial life in returned geological samples and planetary protection.
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Affiliation(s)
- Alastair W Tait
- School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia
- Biological and Environmental Sciences, University of Stirling, Stirling, United Kingdom
| | - Emma J Gagen
- School of Earth and Environmental Sciences, The University of Queensland, St. Lucia, Australia
| | - Siobhan A Wilson
- School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada
| | - Andrew G Tomkins
- School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia
| | - Gordon Southam
- School of Earth and Environmental Sciences, The University of Queensland, St. Lucia, Australia
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Draft Genome Sequence of Bacillus safensis RP10, Isolated from Soil in the Atacama Desert, Chile. Microbiol Resour Announc 2019; 8:8/44/e01150-19. [PMID: 31672748 PMCID: PMC6953511 DOI: 10.1128/mra.01150-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Genome analysis of Bacillus safensis RP10, a strain from the soil of Atacama Desert in northern Chile, reflects a bacterium adapted to live in soil containing high levels of heavy metals, high salt conditions, and low carbon and energy sources.
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27
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Habitability of Mars: How Welcoming Are the Surface and Subsurface to Life on the Red Planet? GEOSCIENCES 2019. [DOI: 10.3390/geosciences9090361] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mars is a planet of great interest in the search for signatures of past or present life beyond Earth. The years of research, and more advanced instrumentation, have yielded a lot of evidence which may be considered by the scientific community as proof of past or present habitability of Mars. Recent discoveries including seasonal methane releases and a subglacial lake are exciting, yet challenging findings. Concurrently, laboratory and environmental studies on the limits of microbial life in extreme environments on Earth broaden our knowledge of the possibility of Mars habitability. In this review, we aim to: (1) Discuss the characteristics of the Martian surface and subsurface that may be conducive to habitability either in the past or at present; (2) discuss laboratory-based studies on Earth that provide us with discoveries on the limits of life; and (3) summarize the current state of knowledge in terms of direction for future research.
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