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Jiang Y, Liu J, Wei X, Wang R, Li Y, Liu Y, Xiao P, Cai Y, Shao J, Zhang Z. Biochar leachate reduces primary nitrogen assimilation by inhibiting nitrogen fixation and microbial nitrate assimilation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170608. [PMID: 38307291 DOI: 10.1016/j.scitotenv.2024.170608] [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: 08/14/2023] [Revised: 01/11/2024] [Accepted: 01/30/2024] [Indexed: 02/04/2024]
Abstract
Biochar contains biotoxic aromatic compounds, and their influence on nitrogen-fixing cyanobacteria, the critical nitrogen fixer in paddy soil, has never been tested. Here, the physiological, metabolomic, and transcriptomic analyses of Nostoc sp. PCC7120 in response to biochar leachate were performed. The results suggested that biochar leachate inhibited the efficiency of photosynthesis, nitrogen fixation, and nitrate assimilation activities of nitrogen-fixing cyanobacteria. Biochar leachate containing aromatic compounds and odd- and long-chain saturated fatty acids impaired the membrane structure and antenna pigments, damaged the D1 protein of the oxygen evolution complex, and eventually decreased the electron transfer chain activity of photosystem II. Moreover, the nitrogen fixation and nitrate assimilation abilities of nitrogen-fixing cyanobacteria were inhibited by a decrease in photosynthetic productivity. A decrease in iron absorption was another factor limiting nitrogen fixation efficiency. Our study highlights that biochar with relatively high contents of dissolved organic matter poses a risk to primary nitrogen assimilation reduction and ecosystem nitrogen loss. Further evidence of the potential negative effects of biochar leachates on the fixation and assimilation capacity of nitrogen by soil microbes is needed to evaluate the impact of biochar on soil multifunctionality prior to large-scale application.
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Affiliation(s)
- Yuexi Jiang
- College of Environment and Ecology, Hunan Agricultural University, Changsha, Hunan, 410128, PR China; College of Resources, Hunan Agricultural University, Changsha, Hunan, 410128, PR China
| | - Ji Liu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an, Shanxi, 710061, PR China; College of Urban and Environmental Sciences, Central China Normal University, Wuhan, Hubei, 430079, PR China; Department of Ecohydrology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, 12587, Germany
| | - Xiaomeng Wei
- College of Natural Resources and Environment, Northwest Agriculture and Forestry University, Yangling, Shanxi, 712100, PR China
| | - Rumeng Wang
- College of Resources, Hunan Agricultural University, Changsha, Hunan, 410128, PR China
| | - Yanyan Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions and the Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, PR China
| | - Yang Liu
- College of Life Sciences, Henan Normal University, Xinxiang, Henan, 453007, PR China
| | - Peng Xiao
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, College of Life and Environmental Science, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China
| | - Yixiang Cai
- Key Laboratory of Agro-ecological Processes in Subtropical Regions and the Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, PR China
| | - Jihai Shao
- College of Environment and Ecology, Hunan Agricultural University, Changsha, Hunan, 410128, PR China.
| | - Zhenhua Zhang
- College of Resources, Hunan Agricultural University, Changsha, Hunan, 410128, PR China
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Seki Y, Eguchi Y, Taoka A. Influence of protozoan grazing on magnetotactic bacteria on intracellular and extracellular iron content. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:181-187. [PMID: 36779255 PMCID: PMC10464679 DOI: 10.1111/1758-2229.13140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 12/28/2022] [Indexed: 05/06/2023]
Abstract
Magnetotactic bacteria (MTB) ubiquitously inhabit the oxic-anoxic interface or anaerobic areas of aquatic environments. MTB biomineralize magnetite or greigite crystals and synthesize an organelle known as magnetosome. This intrinsic ability of MTB allows them to accumulate iron to levels 100-1000 times higher than those in non-magnetotactic bacteria (non-MTB). Therefore, MTB considerably contributes to the global iron cycle as primary iron suppliers in the aquatic environmental food chain. However, to the best of our knowledge, there have been no reports describing the effects of trophic interactions between MTB and their protist grazers on the iron distributions in MTB grazers and the extracellular milieu. Herein, we evaluated the effects of MTB grazing using a model species of protist (Tetrahymena pyriformis) and a model species of MTB (Magnetospirillum magneticum AMB-1). MTB-fed T. pyriformis exhibited a magnetic response and contained magnetite crystals in their vacuoles. Fluorescence imaging using a ferrous ion-specific fluorescent dye revealed that the cellular ferrous ion content was five times higher in MTB-fed T. pyriformis than in non-MTB grazers. Moreover, soluble iron concentrations in the spent media increased with time during MTB predation. This study provides experimental evidence to delineate the importance of trophic interactions of MTB on iron distributions.
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Affiliation(s)
- Yusuke Seki
- Institute of Science and EngineeringKanazawa UniversityKakuma‐machi, KanazawaIshikawaJapan
| | - Yukako Eguchi
- Institute for Promotion of Diversity and InclusionKanazawa UniversityKakuma‐machi, KanazawaIshikawaJapan
| | - Azuma Taoka
- Institute of Science and EngineeringKanazawa UniversityKakuma‐machi, KanazawaIshikawaJapan
- Nano Life Science Institute (WPI‐NanoLSI)Kanazawa UniversityKakuma‐machi, KanazawaIshikawaJapan
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Biomineralization and biotechnological applications of bacterial magnetosomes. Colloids Surf B Biointerfaces 2022; 216:112556. [PMID: 35605573 DOI: 10.1016/j.colsurfb.2022.112556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/27/2022] [Accepted: 05/07/2022] [Indexed: 01/13/2023]
Abstract
Magnetosomes intracellularly biomineralized by Magnetotactic bacteria (MTB) are membrane-enveloped nanoparticles of the magnetic minerals magnetite (Fe3O4) or greigite (Fe3S4). MTB thrive in oxic-anoxic interface and exhibit magnetotaxis due to the presence of magnetosomes. Because of the unique characteristic and bionavigation inspiration of magnetosomes, MTB has been a subject of study focused on by biologists, medical pharmacologists, geologists, and physicists since the discovery. We herein first briefly review the features of MTB and magnetosomes. The recent insights into the process and mechanism for magnetosome biomineralization including iron uptake, magnetosome membrane invagination, iron mineralization and magnetosome chain assembly are summarized in detail. Additionally, the current research progress in biotechnological applications of magnetosomes is also elucidated, such as drug delivery, MRI image contrast, magnetic hyperthermia, wastewater treatment, and cell separation. This review would expand our understanding of biomineralization and biotechnological applications of bacterial magnetosomes.
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Schaible GA, Kohtz AJ, Cliff J, Hatzenpichler R. Correlative SIP-FISH-Raman-SEM-NanoSIMS links identity, morphology, biochemistry, and physiology of environmental microbes. ISME COMMUNICATIONS 2022; 2:52. [PMID: 37938730 PMCID: PMC9723565 DOI: 10.1038/s43705-022-00134-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/23/2022] [Accepted: 06/09/2022] [Indexed: 05/08/2023]
Abstract
Microscopic and spectroscopic techniques are commonly applied to study microbial cells but are typically used on separate samples, resulting in population-level datasets that are integrated across different cells with little spatial resolution. To address this shortcoming, we developed a workflow that correlates several microscopic and spectroscopic techniques to generate an in-depth analysis of individual cells. By combining stable isotope probing (SIP), fluorescence in situ hybridization (FISH), scanning electron microscopy (SEM), confocal Raman microspectroscopy (Raman), and nano-scale secondary ion mass spectrometry (NanoSIMS), we illustrate how individual cells can be thoroughly interrogated to obtain information about their taxonomic identity, structure, physiology, and metabolic activity. Analysis of an artificial microbial community demonstrated that our correlative approach was able to resolve the activity of single cells using heavy water SIP in conjunction with Raman and/or NanoSIMS and establish their taxonomy and morphology using FISH and SEM. This workflow was then applied to a sample of yet uncultured multicellular magnetotactic bacteria (MMB). In addition to establishing their identity and activity, backscatter electron microscopy (BSE), NanoSIMS, and energy-dispersive X-ray spectroscopy (EDS) were employed to characterize the magnetosomes within the cells. By integrating these techniques, we demonstrate a cohesive approach to thoroughly study environmental microbes on a single-cell level.
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Affiliation(s)
- George A Schaible
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
- Thermal Biology Institute, Montana State University, Bozeman, MT, 59717, USA
| | - Anthony J Kohtz
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
- Thermal Biology Institute, Montana State University, Bozeman, MT, 59717, USA
| | - John Cliff
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Roland Hatzenpichler
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA.
- Thermal Biology Institute, Montana State University, Bozeman, MT, 59717, USA.
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717, USA.
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Magnetotactic bacteria and magnetofossils: ecology, evolution and environmental implications. NPJ Biofilms Microbiomes 2022; 8:43. [PMID: 35650214 PMCID: PMC9160268 DOI: 10.1038/s41522-022-00304-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 05/04/2022] [Indexed: 11/08/2022] Open
Abstract
Magnetotactic bacteria (MTB) are a group of phylogenetically diverse and morphologically varied microorganisms with a magnetoresponsive capability called magnetotaxis or microbial magnetoreception. MTB are a distinctive constituent of the microbiome of aquatic ecosystems because they use Earth's magnetic field to align themselves in a north or south facing direction and efficiently navigate to their favored microenvironments. They have been identified worldwide from diverse aquatic and waterlogged microbiomes, including freshwater, saline, brackish and marine ecosystems, and some extreme environments. MTB play important roles in the biogeochemical cycling of iron, sulphur, phosphorus, carbon and nitrogen in nature and have been recognized from in vitro cultures to sequester heavy metals like selenium, cadmium, and tellurium, which makes them prospective candidate organisms for aquatic pollution bioremediation. The role of MTB in environmental systems is not limited to their lifespan; after death, fossil magnetosomal magnetic nanoparticles (known as magnetofossils) are a promising proxy for recording paleoenvironmental change and geomagnetic field history. Here, we summarize the ecology, evolution, and environmental function of MTB and the paleoenvironmental implications of magnetofossils in light of recent discoveries.
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Zhao D, Yang J, Zhang G, Lu D, Zhang S, Wang W, Yan L. Potential and whole-genome sequence-based mechanism of elongated-prismatic magnetite magnetosome formation in Acidithiobacillus ferrooxidans BYM. World J Microbiol Biotechnol 2022; 38:121. [DOI: 10.1007/s11274-022-03308-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/13/2022] [Indexed: 01/15/2023]
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7
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Rajalakshmi A, Anjukam E, Ramesh M, Kavitha K, Puvanakrishnan R, Ramesh B. A novel colorimetric technique for estimating iron in magnetosomes of magnetotactic bacteria based on linear regression. Arch Microbiol 2022; 204:282. [PMID: 35471713 DOI: 10.1007/s00203-022-02901-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/18/2022] [Accepted: 04/04/2022] [Indexed: 11/25/2022]
Abstract
Magnetotactic bacteria (MTB) use iron from their habitat to create magnetosomes, a unique organelle required for magnetotaxis. Due to a lack of cost-effective assay methods for estimating iron in magnetosomes, research on MTB and iron-rich magnetosomes is limited. A systemized assay was established in this study to quantify iron in MTB using ferric citrate colorimetric estimation. With a statistically significant R2 value of 0.9935, the iron concentration range and wavelength for iron estimation were optimized using linear regression. This colorimetric approach and the inductively coupled plasma optical emission spectrometry (ICP-OES) exhibited an excellent correlation R2 value of 0.961 in the validatory correlative study of the iron concentration in the isolated magnetotactic bacterial strains. In large-scale screening studies, this less-expensive strategy could be advantageous.
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Affiliation(s)
- Arumugam Rajalakshmi
- Research Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India
| | - Elamaran Anjukam
- Research Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India
| | - Manickam Ramesh
- Research Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India
| | - Kuppuswamy Kavitha
- Research Department of Microbiology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India
| | - Rengarajulu Puvanakrishnan
- Research Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India
| | - Balasubramanian Ramesh
- Research Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram, Tamil Nadu, 631561, India.
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Amor M, Faivre D, Corvisier J, Tharaud M, Busigny V, Komeili A, Guyot F. Defining Local Chemical Conditions in Magnetosomes of Magnetotactic Bacteria. J Phys Chem B 2022; 126:2677-2687. [PMID: 35362974 PMCID: PMC9098202 DOI: 10.1021/acs.jpcb.2c00752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Defining chemical properties of intracellular organelles is necessary to determine their function(s) as well as understand and mimic the reactions they host. However, the small size of bacterial and archaeal microorganisms often prevents defining local intracellular chemical conditions in a similar way to what has been established for eukaryotic organelles. This work proposes to use magnetite (Fe3O4) nanocrystals contained in magnetosome organelles of magnetotactic bacteria as reporters of elemental composition, pH, and redox potential of a hypothetical environment at the site of formation of intracellular magnetite. This methodology requires combining recent single-cell mass spectrometry measurements together with elemental composition of magnetite in trace and minor elements. It enables a quantitative characterization of chemical disequilibria of 30 chemical elements between the intracellular and external media of magnetotactic bacteria, revealing strong transfers of elements with active influx or efflux processes that translate into elemental accumulation (Mo, Se, and Sn) or depletion (Sr and Bi) in the bacterial internal medium of up to seven orders of magnitude relative to the extracellular medium. Using this concept, we show that chemical conditions in magnetosomes are compatible with a pH of 7.5-9.5 and a redox potential of -0.25 to -0.6 V.
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Affiliation(s)
- Matthieu Amor
- Aix-Marseille Université, CEA, CNRS, BIAM, 13108 Saint-Paul-lez-Durance, France.,Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Damien Faivre
- Aix-Marseille Université, CEA, CNRS, BIAM, 13108 Saint-Paul-lez-Durance, France
| | - Jérôme Corvisier
- Mines ParisTech, PSL Research University, Centre de Géosciences, 35 rue Saint Honoré, Fontainebleau Cedex 77305, France
| | - Mickaël Tharaud
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris F-75005, France
| | - Vincent Busigny
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris F-75005, France.,Institut Universitaire de France, Paris 75005, France
| | - Arash Komeili
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, United States
| | - François Guyot
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Muséum National d'Histoire Naturelle, Sorbonne Université, UMR 7590 CNRS, 61 rue Buffon, 75005 Paris, France
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9
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Liu T, Da H, Zhang S, Wang W, Pan H, Yan L. Magnetotactic bacteria in vertical sediments of volcanic lakes in NE China appear Alphaproteobacteria dominated distribution regardless of waterbody types. World J Microbiol Biotechnol 2022; 38:76. [PMID: 35304669 DOI: 10.1007/s11274-022-03262-z] [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: 10/02/2021] [Accepted: 03/03/2022] [Indexed: 10/18/2022]
Abstract
Magnetotactic bacteria (MTB) distribute widely in sediment habitats and play critical roles in iron cycling. Here, the vertical distribution of morphology and phylogenetic diversity of MTB in sediments (0-15 cm) of three lakes (open waterbody, Bailonghu, BL; semi-enclosed waterbody, Yaoquanhu, YQ; enclosed waterbody, Yueyapao, YY) in Wudalianchi volcanic field (China) were investigated. TEM showed the appearance of coccoid, rod-shaped, oval-shaped, and arc-shaped MTB. With the increase of BL sediment depth, the number of rod-shaped and spherical MTB decreased and increased, respectively. High-throughput sequencing indicated that Alphaproteobacterial MTB dominantly thrived in these lakes regardless of waterbody types. In BL and YY, the dominant genus was Magnetospirillum (44.99-70.80%) which showed a peak in the middle layer. In YQ, the genus Magnetospira was dominant in the upper (52.36%) and middle (66.56%) layer and Magnetococcus (69.63%) existed dominantly in the bottom layer. The vertical distribution of MTB in sediments of these lakes decreased first and then increased. Functional analysis showed that ABC transporter and two-component system of MTB changed significantly with the sediment depth. RDA indicated that the distribution of Magnetospirillum was positively associated with sulfide, pH, and TC. These findings will expand our knowledge of the vertical distribution of MTB in volcanic lakes.
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Affiliation(s)
- Tao Liu
- 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, People's Republic of China
| | - Huiyun Da
- 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, People's Republic of 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, People's Republic of 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, People's Republic of China.,Engineering Research Center of Processing and Utilization of Grain By-Products, Ministry of Education, Daqing, 163319, People's Republic of China
| | - Hong Pan
- Institute of Natural Resources and Ecology, Heilongjiang Academy of Science, Harbin, 150090, People's Republic of 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, People's Republic of China. .,Engineering Research Center of Processing and Utilization of Grain By-Products, Ministry of Education, Daqing, 163319, People's Republic of China.
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Barr CR, Bedrossian M, Lohmann KJ, Nealson KH. Magnetotactic bacteria: concepts, conundrums, and insights from a novel in situ approach using digital holographic microscopy (DHM). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:107-124. [DOI: 10.1007/s00359-022-01543-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 11/25/2022]
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Global Analysis of Biomineralization Genes in Magnetospirillum magneticum AMB-1. mSystems 2022; 7:e0103721. [PMID: 35076272 PMCID: PMC8788322 DOI: 10.1128/msystems.01037-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Magnetotactic bacteria (MTB) are a phylogenetically diverse group of bacteria remarkable for their ability to biomineralize magnetite (Fe3O4) or greigite (Fe3S4) in organelles called magnetosomes. The majority of genes required for magnetosome formation are encoded by a magnetosome gene island (MAI). Most previous genetic studies of MTB have focused on the MAI, using screens to identify key MAI genes or targeted genetics to isolate specific genes and their function in one specific growth condition. This is the first study that has taken an unbiased approach to look at many different growth conditions to reveal key genes both inside and outside the MAI. Here, we conducted random barcoded transposon mutagenesis (RB-TnSeq) in Magnetospirillum magneticum AMB-1. We generated a library of 184,710 unique strains in a wild-type background, generating ∼34 mutant strains for each gene. RB-TnSeq also allowed us to determine the essential gene set of AMB-1 under standard laboratory growth conditions. To pinpoint novel genes that are important for magnetosome formation, we subjected the library to magnetic selection screens under varied growth conditions. We compared biomineralization under standard growth conditions to biomineralization under high-iron and anaerobic conditions, respectively. Strains with transposon insertions in the MAI gene mamT had an exacerbated biomineralization defect under both high-iron and anaerobic conditions compared to standard conditions, adding to our knowledge of the role of MamT in magnetosome formation. Mutants in an ex-MAI gene, amb4151, are more magnetic than wild-type cells under anaerobic conditions. All three of these phenotypes were validated by creating a markerless deletion strain of the gene and evaluating with TEM imaging. Overall, our results indicate that growth conditions affect which genes are required for biomineralization and that some MAI genes may have more nuanced functions than was previously understood. IMPORTANCE Magnetotactic bacteria (MTB) are a group of bacteria that can form nano-sized crystals of magnetic minerals. MTB are likely an important part of their ecosystems, because they can account for up to a third of the microbial biomass in an aquatic habitat and consume large amounts of iron, potentially impacting the iron cycle. The ecology of MTB is relatively understudied; however, the cell biology and genetics of MTB have been studied for decades. Here, we leverage genetic studies of MTB to inform environmental studies. We expand the genetic toolset for studying MTB in the lab and identify novel genes, or functions of genes, that have an impact on biomineralization.
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12
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Zhu Y. Single-cell Analysis Based on ICP-MS. ANAL SCI 2021; 37:1653-1654. [PMID: 34897178 DOI: 10.2116/analsci.highlights2112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yanbei Zhu
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)
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13
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Qin W, Stärk HJ, Reemtsma T. Ruthenium red: a highly efficient and versatile cell staining agent for single-cell analysis using inductively coupled plasma time-of-flight mass spectrometry. Analyst 2021; 146:6753-6759. [PMID: 34643628 DOI: 10.1039/d1an01143j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Staining of biological cells with heavy metals can increase their visibility in mass spectrometry. In this study, the potential of ruthenium red (RR) as a staining agent for single-cell analysis by inductively coupled plasma time-of-flight mass spectrometry (SC-ICP-TOF-MS) is explored using two different yeast strains and one algal species. Time-of-flight mass spectrometry allows the simultaneous detection of Ru and multiple intrinsic elements in single cells. Ru has a better correlation with Mg than with P in Saccharomyces cerevisiae (S. cerevisiae) cells. For the three tested strains, the staining efficiency of RR exceeded 96%; the staining strengths were 30-32 ag μm-2 for the yeast cells and 59 ag μm-2 for the algal cells. By deriving the cell volume of single cells from their Ru mass, the concentration of Mg and P in individual cells of S. cerevisiae can be calculated. Elemental concentrations of Mg and P were highly variable in the cell individuals, with their 25-75 percentile values of 0.10-0.19 and 0.76-2.07 fg μm-3, respectively. RR staining has several advantages: it is fast, does not affect cell viability and is highly efficient. Provided that the shape of the individual cells of a culture is similar, Ru staining allows the elemental content to be directly correlated with the cell volume to accurately calculate the intracellular concentration of target elements in single cells. Therefore, RR can be a promising cell staining agent for future application in SC-ICP-TOF-MS research.
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Affiliation(s)
- Wen Qin
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.
| | - Hans-Joachim Stärk
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.
| | - Thorsten Reemtsma
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany. .,Institute of Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103, Leipzig, Germany
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Liu T, Bolea-Fernandez E, Mangodt C, De Wever O, Vanhaecke F. Single-event tandem ICP-mass spectrometry for the quantification of chemotherapeutic drug-derived Pt and endogenous elements in individual human cells. Anal Chim Acta 2021; 1177:338797. [PMID: 34482885 DOI: 10.1016/j.aca.2021.338797] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/05/2021] [Accepted: 06/22/2021] [Indexed: 11/27/2022]
Abstract
Single cell - tandem ICP-mass spectrometry (SC-ICP-MS/MS) was used for the determination of the absolute amount of Pt (coming from exposure to various concentration levels of cisplatin as a chemotherapeutic drug) and five endogenous elements (P, S, Fe, Cu and Zn) in individual human cells of three different types - Raji, Jurkat and Y79. Optimum conditions were obtained by using a sample introduction unit transporting cell suspension containing approx. 5 × 104 cells per mL at a flow rate of 10 μL min-1 to a nebulizer with narrow internal diameter (250 μm i.d.), mounted onto a total consumption spray chamber. Interference-free conditions were obtained in tandem MS mode (i) for P and S by pressurizing the collision/reaction cell (CRC) with O2 and monitoring the PO+ and SO + reaction product ions and (ii) for Fe by pressurizing the CRC with NH3 and monitoring the Fe(NH3)2+ reaction product ion. The quantification approach was validated by comparison of the absolute amounts of the target elements (in fg per cell) as obtained using SC-ICP-MS/MS with those obtained after acid digestion of approx. 2 × 106 cells and subsequent solution ICP-MS/MS analysis ("bulk" analysis). A higher Pt cell content was observed upon increasing the concentration of the cisplatin solution the cells were exposed to during 24 h. The Pt mass per cell (fg) increased linearly as a function of the cisplatin concentration, but a higher Pt uptake was found in the case of Jurkat cells compared to the other cell types. A cell viability assay showed a lack of chemosensitivity to cisplatin below 200 μM for the Raji and Y79 cell line, but an IC50 value of 11.1 ± 1.3 μM for Jurkat cells. This difference in chemo-responsiveness between the different cell types supported the difference in Pt uptake as indicated via SC-ICP-MS analysis. The increasing level of Pt did not have a marked effect on the contents of the endogenous elements monitored in Raji and Y79 cells, but a decrease in the P and S cell content upon increasing cisplatin treatment was observed for Jurkat cells. This can most likely be attributed to stress induced by the chemotherapeutic treatment in cells showing chemosensitivity towards cisplatin. The results also indicate differences in the absolute amount of endogenous element per cell between different cell types, suggesting the potential of SC-ICP-MS as a "metallo-fingerprinting" tool.
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Affiliation(s)
- Tong Liu
- Ghent University, Department of Chemistry, Atomic & Mass Spectrometry, A&MS Research Group, Campus Sterre, Krijgslaan 281-S12, 9000, Ghent, Belgium; Cancer Research Institute Ghent - CRIG, 9000, Ghent, Belgium
| | - Eduardo Bolea-Fernandez
- Ghent University, Department of Chemistry, Atomic & Mass Spectrometry, A&MS Research Group, Campus Sterre, Krijgslaan 281-S12, 9000, Ghent, Belgium; Cancer Research Institute Ghent - CRIG, 9000, Ghent, Belgium.
| | - Christophe Mangodt
- Ghent University, Department of Human Structure and Repair, Laboratory of Experimental Cancer Research - LECR, C. Heymanslaan 10, 9000, Ghent, Belgium; Cancer Research Institute Ghent - CRIG, 9000, Ghent, Belgium
| | - Olivier De Wever
- Ghent University, Department of Human Structure and Repair, Laboratory of Experimental Cancer Research - LECR, C. Heymanslaan 10, 9000, Ghent, Belgium; Cancer Research Institute Ghent - CRIG, 9000, Ghent, Belgium
| | - Frank Vanhaecke
- Ghent University, Department of Chemistry, Atomic & Mass Spectrometry, A&MS Research Group, Campus Sterre, Krijgslaan 281-S12, 9000, Ghent, Belgium; Cancer Research Institute Ghent - CRIG, 9000, Ghent, Belgium
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15
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Zhang W, Wang Y, Liu L, Pan Y, Lin W. Identification and Genomic Characterization of Two Previously Unknown Magnetotactic Nitrospirae. Front Microbiol 2021; 12:690052. [PMID: 34385986 PMCID: PMC8353452 DOI: 10.3389/fmicb.2021.690052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/29/2021] [Indexed: 11/23/2022] Open
Abstract
Magnetotactic bacteria (MTB) are a group of microbes that biomineralize membrane-bound, nanosized magnetite (Fe3O4), and/or greigite (Fe3S4) crystals in intracellular magnetic organelle magnetosomes. MTB belonging to the Nitrospirae phylum can form up to several hundreds of Fe3O4 magnetosome crystals and dozens of sulfur globules in a single cell. These MTB are widespread in aquatic environments and sometimes account for a significant proportion of microbial biomass near the oxycline, linking these lineages to the key steps of global iron and sulfur cycling. Despite their ecological and biogeochemical importance, our understanding of the diversity and ecophysiology of magnetotactic Nitrospirae is still very limited because this group of MTB remains unculturable. Here, we identify and characterize two previously unknown MTB populations within the Nitrospirae phylum through a combination of 16S rRNA gene-based and genome-resolved metagenomic analyses. These two MTB populations represent distinct morphotypes (rod-shaped and coccoid, designated as XYR, and XYC, respectively), and both form more than 100 bullet-shaped magnetosomal crystals per cell. High-quality draft genomes of XYR and XYC have been reconstructed, and they represent a novel species and a novel genus, respectively, according to their average amino-acid identity values with respect to available genomes. Accordingly, the names Candidatus Magnetobacterium cryptolimnobacter and Candidatus Magnetomicrobium cryptolimnococcus for XYR and XYC, respectively, were proposed. Further comparative genomic analyses of XYR, XYC, and previously reported magnetotactic Nitrospirae reveal the general metabolic potential of this MTB group in distinct microenvironments, including CO2 fixation, dissimilatory sulfate reduction, sulfide oxidation, nitrogen fixation, or denitrification processes. A remarkably conserved magnetosome gene cluster has been identified across Nitrospirae MTB genomes, indicating its putative important adaptive roles in these bacteria. Taken together, the present study provides novel insights into the phylogenomic diversity and ecophysiology of this intriguing, yet poorly understood MTB group.
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Affiliation(s)
- Wensi Zhang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Li Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yongxin Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Wei Lin
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, China
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16
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Huang J, Jones A, Waite TD, Chen Y, Huang X, Rosso KM, Kappler A, Mansor M, Tratnyek PG, Zhang H. Fe(II) Redox Chemistry in the Environment. Chem Rev 2021; 121:8161-8233. [PMID: 34143612 DOI: 10.1021/acs.chemrev.0c01286] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this paper is to review these recent advances and the current state of knowledge of Fe(II) redox chemistry in the environment. Specifically, this comprehensive review focuses on the redox reactivity of four types of Fe(II) species including aqueous Fe(II), Fe(II) complexed with ligands, minerals bearing structural Fe(II), and sorbed Fe(II) on mineral oxide surfaces. The formation pathways, factors governing the reactivity, insights into potential mechanisms, reactivity comparison, and characterization techniques are discussed with reference to the most recent breakthroughs in this field where possible. We also cover the roles of these Fe(II) species in environmental applications of zerovalent iron, microbial processes, biogeochemical cycling of carbon and nutrients, and their abiotic oxidation related processes in natural and engineered systems.
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Affiliation(s)
- Jianzhi Huang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Adele Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yiling Chen
- Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaopeng Huang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Paul G Tratnyek
- School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
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17
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Menghini S, Ho PS, Gwisai T, Schuerle S. Magnetospirillum magneticum as a Living Iron Chelator Induces TfR1 Upregulation and Decreases Cell Viability in Cancer Cells. Int J Mol Sci 2021; 22:ijms22020498. [PMID: 33419059 PMCID: PMC7825404 DOI: 10.3390/ijms22020498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 11/16/2022] Open
Abstract
Interest has grown in harnessing biological agents for cancer treatment as dynamic vectors with enhanced tumor targeting. While bacterial traits such as proliferation in tumors, modulation of an immune response, and local secretion of toxins have been well studied, less is known about bacteria as competitors for nutrients. Here, we investigated the use of a bacterial strain as a living iron chelator, competing for this nutrient vital to tumor growth and progression. We established an in vitro co-culture system consisting of the magnetotactic strain Magnetospirillum magneticum AMB-1 incubated under hypoxic conditions with human melanoma cells. Siderophore production by 108 AMB-1/mL in human transferrin (Tf)-supplemented media was quantified and found to be equivalent to a concentration of 3.78 µM ± 0.117 µM deferoxamine (DFO), a potent drug used in iron chelation therapy. Our experiments revealed an increased expression of transferrin receptor 1 (TfR1) and a significant decrease of cancer cell viability, indicating the bacteria’s ability to alter iron homeostasis in human melanoma cells. Our results show the potential of a bacterial strain acting as a self-replicating iron-chelating agent, which could serve as an additional mechanism reinforcing current bacterial cancer therapies.
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Ye D, Li M, Xie Y, Chen B, Han Y, Liu S, Wei QH, Gu N. Optical Imaging and High-Accuracy Quantification of Intracellular Iron Contents. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2005474. [PMID: 33306269 DOI: 10.1002/smll.202005474] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/19/2020] [Indexed: 06/12/2023]
Abstract
Precise quantification of intracellular iron contents is important to biomedical applications of magnetic nanoparticles. Current approaches for iron quantification rely on specialized instruments while most only yield iron quantities averaged over plenty of cells. Here, a simple and robust approach, combining digital optical microscopy with the Beer-Lambert's law, that allows for imaging stainable iron distribution in individual cells and the quantification of stainable iron contents with an unprecedented accuracy of femtogram per pixel, is presented. It is further shown that this approach enables studying of the internalization and reduction dynamics of super-paramagnetic iron oxide nanoparticles (SPIONs) by stem cells in single cell level.
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Affiliation(s)
- Dewen Ye
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210009, China
| | - Mingxi Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210009, China
| | - Yuanyuan Xie
- Center for Clinic Stem Cell Research, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Bo Chen
- Materials Science and Devices Institute, Suzhou University of Science and Technology, 1 Kerui Road, Suzhou, 215009, China
| | - Yuexia Han
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210009, China
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Qi-Huo Wei
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- Department of Physics, Nanjing Medical University, Nanjing, 211166, China
| | - Ning Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210009, China
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Lin W, Zhang W, Paterson GA, Zhu Q, Zhao X, Knight R, Bazylinski DA, Roberts AP, Pan Y. Expanding magnetic organelle biogenesis in the domain Bacteria. MICROBIOME 2020; 8:152. [PMID: 33126926 PMCID: PMC7602337 DOI: 10.1186/s40168-020-00931-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The discovery of membrane-enclosed, metabolically functional organelles in Bacteria has transformed our understanding of the subcellular complexity of prokaryotic cells. Biomineralization of magnetic nanoparticles within magnetosomes by magnetotactic bacteria (MTB) is a fascinating example of prokaryotic organelles. Magnetosomes, as nano-sized magnetic sensors in MTB, facilitate cell navigation along the local geomagnetic field, a behaviour referred to as magnetotaxis or microbial magnetoreception. Recent discovery of novel MTB outside the traditionally recognized taxonomic lineages suggests that MTB diversity across the domain Bacteria are considerably underestimated, which limits understanding of the taxonomic distribution and evolutionary origin of magnetosome organelle biogenesis. RESULTS Here, we perform the most comprehensive metagenomic analysis available of MTB communities and reconstruct metagenome-assembled MTB genomes from diverse ecosystems. Discovery of MTB in acidic peatland soils suggests widespread MTB occurrence in waterlogged soils in addition to subaqueous sediments and water bodies. A total of 168 MTB draft genomes have been reconstructed, which represent nearly a 3-fold increase over the number currently available and more than double the known MTB species at the genome level. Phylogenomic analysis reveals that these genomes belong to 13 Bacterial phyla, six of which were previously not known to include MTB. These findings indicate a much wider taxonomic distribution of magnetosome organelle biogenesis across the domain Bacteria than previously thought. Comparative genome analysis reveals a vast diversity of magnetosome gene clusters involved in magnetosomal biogenesis in terms of gene content and synteny residing in distinct taxonomic lineages. Phylogenetic analyses of core magnetosome proteins in this largest available and taxonomically diverse dataset support an unexpectedly early evolutionary origin of magnetosome biomineralization, likely ancestral to the origin of the domain Bacteria. CONCLUSIONS These findings expand the taxonomic and phylogenetic diversity of MTB across the domain Bacteria and shed new light on the origin and evolution of microbial magnetoreception. Potential biogenesis of the magnetosome organelle in the close descendants of the last bacterial common ancestor has important implications for our understanding of the evolutionary history of bacterial cellular complexity and emphasizes the biological significance of the magnetosome organelle. Video Abstract.
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Affiliation(s)
- Wei Lin
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
- Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, 100029, China.
| | - Wensi Zhang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
- Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, 100029, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Greig A Paterson
- Department of Earth, Ocean and Ecological Sciences, University of Liverpool, L69 7ZE, Liverpool, UK
| | - Qiyun Zhu
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92037, USA
| | - Xiang Zhao
- Research School of Earth Sciences, Australian National University, ACT, Canberra, 2601, Australia
| | - Rob Knight
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92037, USA
| | - Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, ACT, Canberra, 2601, Australia
| | - Yongxin Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
- Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.
- France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing, 100029, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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20
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Magnetotactic Bacteria Accumulate a Large Pool of Iron Distinct from Their Magnetite Crystals. Appl Environ Microbiol 2020; 86:AEM.01278-20. [PMID: 32887716 PMCID: PMC7642088 DOI: 10.1128/aem.01278-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/21/2020] [Indexed: 12/16/2022] Open
Abstract
Magnetotactic bacteria (MTB) produce iron-based intracellular magnetic crystals. They represent a model system for studying iron homeostasis and biomineralization in microorganisms. MTB sequester a large amount of iron in their crystals and have thus been proposed to significantly impact the iron biogeochemical cycle. Several studies proposed that MTB could also accumulate iron in a reservoir distinct from their crystals. Here, we present a chemical and magnetic methodology for quantifying the iron pools in the magnetotactic strain AMB-1. Results showed that most iron is not contained in crystals. We then adapted protocols for the fluorescent Fe(II) detection in bacteria and showed that iron could be detected outside crystals using fluorescence assays. This work suggests a more complex picture for iron homeostasis in MTB than previously thought. Because iron speciation controls its fate in the environment, our results also provide important insights into the geochemical impact of MTB. Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that form intracellular nanoparticles of magnetite (Fe3O4) or greigite (Fe3S4) in a genetically controlled manner. Magnetite and greigite synthesis requires MTB to transport a large amount of iron from the environment. Most intracellular iron was proposed to be contained within the crystals. However, recent mass spectrometry studies suggest that MTB may contain a large amount of iron that is not precipitated in crystals. Here, we attempted to resolve these discrepancies by performing chemical and magnetic assays to quantify the different iron pools in the magnetite-forming strain Magnetospirillum magneticum AMB-1, as well as in mutant strains showing defects in crystal precipitation, cultivated at various iron concentrations. All results show that magnetite represents at most 30% of the total intracellular iron under our experimental conditions and even less in the mutant strains. We further examined the iron speciation and subcellular localization in AMB-1 using the fluorescent indicator FIP-1, which was designed for the detection of labile Fe(II). Staining with this probe suggests that unmineralized reduced iron is found in the cytoplasm and associated with magnetosomes. Our results demonstrate that, under our experimental conditions, AMB-1 is able to accumulate a large pool of iron distinct from magnetite. Finally, we discuss the biochemical and geochemical implications of these results. IMPORTANCE Magnetotactic bacteria (MTB) produce iron-based intracellular magnetic crystals. They represent a model system for studying iron homeostasis and biomineralization in microorganisms. MTB sequester a large amount of iron in their crystals and have thus been proposed to significantly impact the iron biogeochemical cycle. Several studies proposed that MTB could also accumulate iron in a reservoir distinct from their crystals. Here, we present a chemical and magnetic methodology for quantifying the iron pools in the magnetotactic strain AMB-1. Results showed that most iron is not contained in crystals. We then adapted protocols for the fluorescent Fe(II) detection in bacteria and showed that iron could be detected outside crystals using fluorescence assays. This work suggests a more complex picture for iron homeostasis in MTB than previously thought. Because iron speciation controls its fate in the environment, our results also provide important insights into the geochemical impact of MTB.
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22
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Mansor M, Xu J. Benefits at the nanoscale: a review of nanoparticle-enabled processes favouring microbial growth and functionality. Environ Microbiol 2020; 22:3633-3649. [PMID: 32705763 DOI: 10.1111/1462-2920.15174] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/17/2020] [Accepted: 07/21/2020] [Indexed: 11/29/2022]
Abstract
Nanoparticles are ubiquitous and co-occur with microbial life in every environment on Earth. Interactions between microbes and nanoparticles impact the biogeochemical cycles via accelerating various reaction rates and enabling biological processes at the smallest scales. Distinct from microbe-mineral interactions at large, microbe-nanoparticle interactions may involve higher levels of active recognition and utilization of the reactive, changeable, and thereby 'moldable' nano-sized inorganic phases by microbes, which has been given minimal attention in previous reviews. Here we have compiled the various cases of microbe-nanoparticle interactions with clear and potential benefits to the microbial cells and communities. Specifically, we discussed (i) the high bioavailabilities of nanoparticles due to increased specific surface areas and size-dependent solubility, with a focus on environmentally-relevant iron(III) (oxyhydr)oxides and pyrite, (ii) microbial utilization of nanoparticles as 'nano-tools' for electron transfer, chemotaxis, and storage units, and (iii) speculated benefits of precipitating 'moldable' nanoparticles in extracellular biomineralization. We further discussed emergent questions concerning cellular level responses to nanoparticle-associated cues, and the factors that affect nanoparticles' bioavailabilities beyond size-dependent effects. We end the review by proposing a framework towards more quantitative approaches and by highlighting promising techniques to guide future research in this exciting field.
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Affiliation(s)
- Muammar Mansor
- Geomicrobiology, Center for Applied Geoscience, University of Tuebingen, Tuebingen, 72076, Germany
| | - Jie Xu
- Department of Geological Sciences, the University of Texas at El Paso, El Paso, Texas, 79968, USA
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23
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Amor M, Mathon FP, Monteil CL, Busigny V, Lefevre CT. Iron-biomineralizing organelle in magnetotactic bacteria: function, synthesis and preservation in ancient rock samples. Environ Microbiol 2020; 22:3611-3632. [PMID: 32452098 DOI: 10.1111/1462-2920.15098] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 12/22/2022]
Abstract
Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that incorporate iron from their environment to synthesize intracellular nanoparticles of magnetite (Fe3 O4 ) or greigite (Fe3 S4 ) in a genetically controlled manner. Magnetite and greigite magnetic phases allow MTB to swim towards redox transition zones where they thrive. MTB may represent some of the oldest microorganisms capable of synthesizing minerals on Earth and have been proposed to significantly impact the iron biogeochemical cycle by immobilizing soluble iron into crystals that subsequently fossilize in sedimentary rocks. In the present article, we describe the distribution of MTB in the environment and discuss the possible function of the magnetite and greigite nanoparticles. We then provide an overview of the chemical mechanisms leading to iron mineralization in MTB. Finally, we update the methods used for the detection of MTB crystals in sedimentary rocks and present their occurrences in the geological record.
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Affiliation(s)
- Matthieu Amor
- Aix-Marseille University, CNRS, CEA, UMR7265 Institute of Biosciences and Biotechnologies of Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - François P Mathon
- Aix-Marseille University, CNRS, CEA, UMR7265 Institute of Biosciences and Biotechnologies of Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France.,Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris, F-75005, France
| | - Caroline L Monteil
- Aix-Marseille University, CNRS, CEA, UMR7265 Institute of Biosciences and Biotechnologies of Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Vincent Busigny
- Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris, F-75005, France.,Institut Universitaire de France, Paris, 75005, France
| | - Christopher T Lefevre
- Aix-Marseille University, CNRS, CEA, UMR7265 Institute of Biosciences and Biotechnologies of Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
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Abstract
Many species of bacteria can manufacture materials on a finer scale than those that are synthetically made. These products are often produced within intracellular compartments that bear many hallmarks of eukaryotic organelles. One unique and elegant group of organisms is at the forefront of studies into the mechanisms of organelle formation and biomineralization. Magnetotactic bacteria (MTB) produce organelles called magnetosomes that contain nanocrystals of magnetic material, and understanding the molecular mechanisms behind magnetosome formation and biomineralization is a rich area of study. In this Review, we focus on the genetics behind the formation of magnetosomes and biomineralization. We cover the history of genetic discoveries in MTB and key insights that have been found in recent years and provide a perspective on the future of genetic studies in MTB.
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Affiliation(s)
- Hayley C. McCausland
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Arash Komeili
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
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