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Pang B, Zheng H, Ma S, Tian J, Wen Y. Nitric oxide sensor NsrR is the key direct regulator of magnetosome formation and nitrogen metabolism in Magnetospirillum. Nucleic Acids Res 2024; 52:2924-2941. [PMID: 38197240 PMCID: PMC11014258 DOI: 10.1093/nar/gkad1230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Nitric oxide (NO) plays an essential role as signaling molecule in regulation of eukaryotic biomineralization, but its role in prokaryotic biomineralization is unknown. Magnetospirillum gryphiswaldense MSR-1, a model strain for studies of prokaryotic biomineralization, has the unique ability to form magnetosomes (magnetic organelles). We demonstrate here that magnetosome biomineralization in MSR-1 requires the presence of NsrRMg (an NO sensor) and a certain level of NO. MSR-1 synthesizes endogenous NO via nitrification-denitrification pathway to activate magnetosome formation. NsrRMg was identified as a global transcriptional regulator that acts as a direct activator of magnetosome gene cluster (MGC) and nitrification genes but as a repressor of denitrification genes. Specific levels of NO modulate DNA-binding ability of NsrRMg to various target promoters, leading to enhancing expression of MGC genes, derepressing denitrification genes, and repressing nitrification genes. These regulatory functions help maintain appropriate endogenous NO level. This study identifies for the first time the key transcriptional regulator of major MGC genes, clarifies the molecular mechanisms underlying NsrR-mediated NO signal transduction in magnetosome formation, and provides a basis for a proposed model of the role of NO in the evolutionary origin of prokaryotic biomineralization processes.
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Affiliation(s)
- Bo Pang
- State Key Laboratory of Animal Biotech Breeding and College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Haolan Zheng
- State Key Laboratory of Animal Biotech Breeding and College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shijia Ma
- State Key Laboratory of Animal Biotech Breeding and College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jiesheng Tian
- State Key Laboratory of Animal Biotech Breeding and College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ying Wen
- State Key Laboratory of Animal Biotech Breeding and College of Biological Sciences, China Agricultural University, Beijing 100193, China
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Dziuba MV, Müller FD, Pósfai M, Schüler D. Exploring the host range for genetic transfer of magnetic organelle biosynthesis. Nat Nanotechnol 2024; 19:115-123. [PMID: 37735601 DOI: 10.1038/s41565-023-01500-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 08/04/2023] [Indexed: 09/23/2023]
Abstract
Magnetosomes produced by magnetotactic bacteria have great potential for application in biotechnology and medicine due to their unique physicochemical properties and high biocompatibility. Attempts to transfer the genes for magnetosome biosynthesis into non-magnetic organisms have had mixed results. Here we report on a systematic study to identify key components needed for magnetosome biosynthesis after gene transfer. We transfer magnetosome genes to 25 proteobacterial hosts, generating seven new magnetosome-producing strains. We characterize the recombinant magnetosomes produced by these strains and demonstrate that denitrification and anaerobic photosynthesis are linked to the ability to synthesize magnetosomes upon the gene transfer. In addition, we show that the number of magnetosomes synthesized by a foreign host negatively correlates with the guanine-cytosine content difference between the host and the gene donor. Our findings have profound implications for the generation of magnetized living cells and the potential for transgenic biogenic magnetic nanoparticle production.
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Affiliation(s)
- Marina V Dziuba
- Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
| | - Frank-Dietrich Müller
- Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany
| | - Mihály Pósfai
- ELKH-PE Environmental Mineralogy Research Group, Veszprém, Hungary
- Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprém, Hungary
| | - Dirk Schüler
- Department of Microbiology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Bayreuth, Germany.
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Chen H, Shi H, Chen C, Jiao Y, Wang P, Chen C, Li J, Wu LF, Song T. Effects of static magnetic field on the sulfate metabolic pathway involved in Magnetospirillum magneticum AMB-1 cell growth and magnetosome formation. J Appl Microbiol 2023; 134:lxad302. [PMID: 38066686 DOI: 10.1093/jambio/lxad302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/10/2023] [Accepted: 12/08/2023] [Indexed: 12/27/2023]
Abstract
AIMS Magnetotactic bacteria (MTB) can use their unique intracellular magnetosome organelles to swim along the Earth's magnetic field. They play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have shown that the applied magnetic fields could affect the magnetosome formation and antioxidant defense systems in MTB. However, the molecular mechanisms by which magnetic fields affect MTB cells remain unclear. We aim to better understand the dark at 28°C-29°C for 20 h, as shownthe interactions between magnetic fields and cells, and the mechanism of MTB adaptation to magnetic field at molecular levels. METHODS AND RESULTS We performed microbiological, transcriptomic, and genetic experiments to analyze the effects of a weak static magnetic field (SMF) exposure on the cell growth and magnetosome formation in the MTB strain Magnetospirillum magneticum AMB-1. The results showed that a 1.5 mT SMF significantly promoted the cell growth but reduced magnetosome formation in AMB-1, compared to the geomagnetic field. Transcriptomic analysis revealed decreased expression of genes primarily involved in the sulfate reduction pathway. Consistently, knockout mutant lacking adenylyl-sulfate kinase CysC did no more react to the SMF and the differences in growth and Cmag disappeared. Together with experimental findings of increased reactive oxidative species in the SMF-treated wild-type strain, we proposed that cysC, as a key gene, can participate in the cell growth and mineralization in AMB-1 by SMF regulation. CONCLUSIONS This study suggests that the magnetic field exposure can trigger a bacterial oxidative stress response involved in AMB-1 growth and magnetosome mineralization by regulating the sulfur metabolism pathway. CysC may serve as a pivotal enzyme in mediating sulfur metabolism to synchronize the impact of SMF on both growth and magnetization of AMB-1.
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Affiliation(s)
- Haitao Chen
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
| | - Hongkai Shi
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changyou Chen
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
| | - Yangkun Jiao
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pingping Wang
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
| | - Chuanfang Chen
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinhua Li
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Long-Fei Wu
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, CNRS, F-13402 Marseille, France
- Aix Marseille University, CNRS, LCB, F-13402 Marseille, France
| | - Tao Song
- Beijing Key Laboratory of Biological Electromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
- France-China International Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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Li S, Luo Z, Wang S, Nan Q, Ji G. Denitrification fractionates N and O isotopes of nitrate following a ratio independent of carbon sources in freshwaters. Environ Microbiol 2023; 25:2404-2415. [PMID: 37503781 DOI: 10.1111/1462-2920.16468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 07/10/2023] [Indexed: 07/29/2023]
Abstract
The stable isotope technique has been used in tracking nitrogen cycling processes, but the isotopic characteristics are influenced by environmental conditions. To better understand the variability of nitrate isotopes in nature, we investigated the influence of organic carbon sources on isotope fractionation characteristics during microbial denitrification. Denitrifying cultures were inoculated with freshwater samples and enriched with five forms of organic compounds, that is, acetate, citrate, glucose, cellobiose, and leucine. Though the isotope enrichment factors of nitrogen and oxygen (15 ε and 18 ε) changed with carbon sources, 18 ε/15 ε always followed a proportionality near 1. Genome-centred metagenomics revealed the enrichment of a few populations, such as Pseudomonas, Enterobacter, and Atlantibacter, most of which contained both NapA- and NarG-type nitrate reductases. Metatranscriptome showed that both NapA and NarG were expressed but to different extents in the enrichments. Furthermore, isotopic data collected from a deep reservoir was analysed. The results showed δ18 O- and δ15 N-nitrate did not correlate in the surface water where nitrification was active, but 18 ε/15 ε followed a proportionality of 1.05 ± 011 in deeper waters (≥ 12 m) where denitrification controlled the nitrate isotope. The independence of 18 ε/15 ε from carbon sources provides an opportunity to determine heterotrophic denitrification and helps the interpretation of nitrate isotopes in freshwaters.
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Affiliation(s)
- Shengjie Li
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
- Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Zhongxin Luo
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
- China Institute of Water Resources and Hydropower Research, Beijing, China
- National Research Center for Sustainable Hydropower Development, Beijing, China
| | - Shuo Wang
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
| | - Qiong Nan
- Institute of Environment Pollution Control and Treatment, College of Environment and Resource Science, Zhejiang University, Hangzhou, China
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
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Hezema NN, Eltarahony MM, Abdel Salam SA. Therapeutic and antioxidant potential of bionanofactory Ochrobactrum sp.-mediated magnetite and zerovalent iron nanoparticles against acute experimental toxoplasmosis. PLoS Negl Trop Dis 2023; 17:e0011655. [PMID: 37801440 PMCID: PMC10558077 DOI: 10.1371/journal.pntd.0011655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/11/2023] [Indexed: 10/08/2023] Open
Abstract
The control of toxoplasmosis, a rampant one health disease, has been focussed on conventional antitoxoplasmic agents with their adverse outcomes, including serious side effects, treatment failure and emergence of drug resistant strains. Nanobiotechnology may provide a strong impetus for versatile alternative therapies against toxoplasmosis. Bionanofactory Ochrobactrum sp. strain CNE2 was recruited for the biosynthesis of functionalized magnetite iron nanoparticles (MNPs) and nanozerovalent iron (nZVI) under aerobic and anaerobic conditions and their therapeutic efficacy was evaluated against acute toxoplasmosis in murine model. The formation of self-functionalized spherical nanoparticles varied in size, identity and surface properties were substantiated. Mice were orally administered 20 mg/kg of each formulation on the initial day of infection and continued for seven consecutive days post infection (PI). Parasitological, ultrastructural, immunological, and biochemical studies were performed for assessment of therapeutic activity of biogenic iron nanoparticles (INPs). Parasitologically, MNPs showed the highest antitoxoplasmic efficacy in terms of 96.82% and 91.87% reduction in mean tachyzoite count in peritoneal fluid and liver impression smears, respectively. Lesser percentage reductions were recorded in nZVI-treated infected subgroup (75.44% and 69.04%). In addition, scanning electron microscopy (SEM) examination revealed remarkable reduction in size and extensive damage to the surface of MNPs-treated tachyzoites. MNPs-treated infected mice revealed a statistically significant increase in the serum levels of both interferon gamma (IFN-γ) to 346.2 ± 4.6 pg/ml and reduced glutathione (GSH) to 8.83 ± 0.30 mg/dl that subsequently exerted malondialdehyde (MDA) quenching action. MNPs showed a superior promising antitoxoplasmic activity with respect to both spiramycin (SPI) and nZVI. To best of our knowledge, this is the first study of a bio-safe oral iron nanotherapeutic agent fabricated via an eco-friendly approach that offers promising potential against acute experimental toxoplasmosis.
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Affiliation(s)
- Nehal Nassef Hezema
- Department of Medical Parasitology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Marwa Moustafa Eltarahony
- Department of Environmental Biotechnology, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, New Borg El-Arab City, Alexandria, Egypt
| | - Sara Ahmed Abdel Salam
- Department of Medical Parasitology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
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de Souza Cabral A, Verdan M, Presciliano R, Silveira F, Correa T, Abreu F. Large-Scale Cultivation of Magnetotactic Bacteria and the Optimism for Sustainable and Cheap Approaches in Nanotechnology. Mar Drugs 2023; 21. [PMID: 36827100 DOI: 10.3390/md21020060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/21/2023] Open
Abstract
Magnetotactic bacteria (MTB), a diverse group of marine and freshwater microorganisms, have attracted the scientific community's attention since their discovery. These bacteria biomineralize ferrimagnetic nanocrystals, the magnetosomes, or biological magnetic nanoparticles (BMNs), in a single or multiple chain(s) within the cell. As a result, cells experience an optimized magnetic dipolar moment responsible for a passive alignment along the lines of the geomagnetic field. Advances in MTB cultivation and BMN isolation have contributed to the expansion of the biotechnological potential of MTB in recent decades. Several studies with mass-cultured MTB expanded the possibilities of using purified nanocrystals and whole cells in nano- and biotechnology. Freshwater MTB were primarily investigated in scaling up processes for the production of BMNs. However, marine MTB have the potential to overcome freshwater species applications due to the putative high efficiency of their BMNs in capturing molecules. Regarding the use of MTB or BMNs in different approaches, the application of BMNs in biomedicine remains the focus of most studies, but their application is not restricted to this field. In recent years, environment monitoring and recovery, engineering applications, wastewater treatment, and industrial processes have benefited from MTB-based biotechnologies. This review explores the advances in MTB large-scale cultivation and the consequent development of innovative tools or processes.
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Riese CN, Wittchen M, Jérôme V, Freitag R, Busche T, Kalinowski J, Schüler D. The transcriptomic landscape of Magnetospirillum gryphiswaldense during magnetosome biomineralization. BMC Genomics 2022; 23:699. [PMID: 36217140 PMCID: PMC9549626 DOI: 10.1186/s12864-022-08913-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 09/23/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND One of the most complex prokaryotic organelles are magnetosomes, which are formed by magnetotactic bacteria as sensors for navigation in the Earth's magnetic field. In the alphaproteobacterium Magnetospirillum gryphiswaldense magnetosomes consist of chains of magnetite crystals (Fe3O4) that under microoxic to anoxic conditions are biomineralized within membrane vesicles. To form such an intricate structure, the transcription of > 30 specific structural genes clustered within the genomic magnetosome island (MAI) has to be coordinated with the expression of an as-yet unknown number of auxiliary genes encoding several generic metabolic functions. However, their global regulation and transcriptional organization in response to anoxic conditions most favorable for magnetite biomineralization are still unclear. RESULTS Here, we compared transcriptional profiles of anaerobically grown magnetosome forming cells with those in which magnetosome biosynthesis has been suppressed by aerobic condition. Using whole transcriptome shotgun sequencing, we found that transcription of about 300 of the > 4300 genes was significantly enhanced during magnetosome formation. About 40 of the top upregulated genes are directly or indirectly linked to aerobic and anaerobic respiration (denitrification) or unknown functions. The mam and mms gene clusters, specifically controlling magnetosome biosynthesis, were highly transcribed, but constitutively expressed irrespective of the growth condition. By Cappable-sequencing, we show that the transcriptional complexity of both the MAI and the entire genome decreased under anaerobic conditions optimal for magnetosome formation. In addition, predominant promoter structures were highly similar to sigma factor σ70 dependent promoters in other Alphaproteobacteria. CONCLUSIONS Our transcriptome-wide analysis revealed that magnetite biomineralization relies on a complex interplay between generic metabolic processes such as aerobic and anaerobic respiration, cellular redox control, and the biosynthesis of specific magnetosome structures. In addition, we provide insights into global regulatory features that have remained uncharacterized in the widely studied model organism M. gryphiswaldense, including a comprehensive dataset of newly annotated transcription start sites and genome-wide operon detection as a community resource (GEO Series accession number GSE197098).
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Affiliation(s)
- Cornelius N Riese
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Manuel Wittchen
- Center for Biotechnology (CeBiTec), University of Bielefeld, Bielefeld, Germany
| | - Valérie Jérôme
- Chair for Process Biotechnology, University of Bayreuth, Bayreuth, Germany
| | - Ruth Freitag
- Chair for Process Biotechnology, University of Bayreuth, Bayreuth, Germany
| | - Tobias Busche
- Center for Biotechnology (CeBiTec), University of Bielefeld, Bielefeld, Germany
| | - Jörn Kalinowski
- Center for Biotechnology (CeBiTec), University of Bielefeld, Bielefeld, Germany
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany.
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Xu B, Yang X, Li Y, Yang K, Xiong Y, Yuan N. Pyrite-Based Autotrophic Denitrifying Microorganisms Derived from Paddy Soils: Effects of Organic Co-Substrate Addition. Int J Environ Res Public Health 2022; 19:11763. [PMID: 36142037 PMCID: PMC9517464 DOI: 10.3390/ijerph191811763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
The presence of organic co-substrate in groundwater and soils is inevitable, and much remains to be learned about the roles of organic co-substrates during pyrite-based denitrification. Herein, an organic co-substrate (acetate) was added to a pyrite-based denitrification system, and the impact of the organic co-substrate on the performance and bacterial community of pyrite-based denitrification processes was evaluated. The addition of organic co-substrate at concentrations higher than 48 mg L-1 inhibited pyrite-based autotrophic denitrification, as no sulfate was produced in treatments with high organic co-substrate addition. In contrast, both competition and promotion effects on pyrite-based autotrophic denitrification occurred with organic co-substrate addition at concentrations of 24 and 48 mg L-1. The subsequent validation experiments suggested that competition had a greater influence than promotion when organic co-substrate was added, even at a low concentration. Thiobacillus, a common chemolithoautotrophic sulfur-oxidizing denitrifier, dominated the system with a relative abundance of 13.04% when pyrite served as the sole electron donor. With the addition of organic co-substrate, Pseudomonas became the dominant genus, with 60.82%, 61.34%, 70.37%, 73.44%, and 35.46% abundance at organic matter concentrations of 24, 48, 120, 240, and 480 mg L-1, respectively. These findings provide an important theoretical basis for the cultivation of pyrite-based autotrophic denitrifying microorganisms for nitrate removal in soils and groundwater.
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Affiliation(s)
- Baokun Xu
- Agricultural Water Conservancy Department, Changjiang River Scientific Research Institute, Wuhan 430010, China
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
- Key Laboratory of River Regulation and Flood Control of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan 430010, China
| | - Xiaoxia Yang
- Chongqing Water Resources Bureau, Chongqing 401147, China
| | - Yalong Li
- Agricultural Water Conservancy Department, Changjiang River Scientific Research Institute, Wuhan 430010, China
| | - Kejun Yang
- School of Law, Zhongnan University of Economics and Law, Wuhan 430073, China
- Agricultural and Rural Department of Hubei Province, Wuhan 430070, China
| | - Yujiang Xiong
- Agricultural Water Conservancy Department, Changjiang River Scientific Research Institute, Wuhan 430010, China
| | - Niannian Yuan
- Agricultural Water Conservancy Department, Changjiang River Scientific Research Institute, Wuhan 430010, China
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Zheng H, Pang B, Li S, Ma S, Xu J, Wen Y, Tian J. Construction of Recombinant Magnetospirillum Strains for Nitrate Removal from Wastewater Based on Magnetic Adsorption. Processes (Basel) 2022; 10:591. [DOI: 10.3390/pr10030591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Nitrate ion (NO3−) in wastewater is a major cause of pollution in aquatic environments worldwide. Magnetospirillum gryphiswaldense (MSR-1) has a complete dissimilatory denitrification pathway, converts NO3− in water into nitrogen (N2) and simultaneously removes ammonium ions (NH4+). We investigated and confirmed direct effects of regulatory protein factors Mg2046 and MgFnr on MSR-1 denitrification pathway by EMSAs and ChIP-qPCR assays. Corresponding mutant strains were constructed. Denitrification efficiency in synthetic wastewater medium during a 12-h cell growth period was significantly higher for mutant strain Δmgfnr (0.456 mmol·L−1·h−1) than for wild-type (0.362 mmol·L−1·h−1). Presence of magnetic particles (magnetosomes) in MSR-1 greatly facilitates collection and isolation of bacterial cells (and activated sludge) by addition of a magnetic field. The easy separation of magnetotactic bacteria, such as MSR-1 and Δmgfnr, from wastewater using magnetic fields is a unique feature that makes them promising candidates for practical application in wastewater treatment and sludge pretreatment.
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McCausland HC, Wetmore KM, Arkin AP, Komeili A. Global Analysis of Biomineralization Genes in Magnetospirillum magneticum AMB-1. mSystems 2022;:e0103721. [PMID: 35076272 DOI: 10.1128/msystems.01037-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Abstract
Abstract
The discovery of magnetosome and magnetotaxis in its most simple form in the magnetotactic bacteria (MTB) had created the tremendous impetus. MTB, spanning multiple phyla, are distributed worldwide, and they form the organelles called magnetosomes for biomineralization. Eight phylotypes of MTB belong to Alphaproteobacteria and Nitrospirae. MTB show preference for specific redox and oxygen concentration. Magnetosome chains function as the internal compass needle and align the bacterial cells passively along the local geomagnetic field (GMF). The nature of magnetosomes produced by MTB and their phylogeny suggest that bullet-shaped magnetites appeared about 3.2 billion years ago with the first magnetosomes. All MTB contains ten genes in conserved mamAB operon for magnetosome chain synthesis of which nine genes are conserved in greigite-producing MTB. Many candidate genes identify the aero-, redox-, and perhaps phototaxis. Among the prokaryotes, the MTB possess the highest number of O2-binding proteins. Magnetofossils serve as an indicator of oxygen and redox levels of the ancient environments. Most descendants of ancestral MTB lost the magnetosome genes in the course of evolution. Environmental conditions initially favored the evolution of MTB and expansion of magnetosome-formation genes. Subsequent changes in atmospheric oxygen concentration have led to changes in the ecology of MTB, loss of magnetosome genes, and evolution of nonMTB.
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Affiliation(s)
- Fatik Baran Mandal
- Department of Zoology, Bankura Christian College, College Road, Bankura, West Bengal, 722101, India
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Eltarahony M, Zaki S, Kamal A, Abd-El-Haleem D. Calcite and Vaterite Biosynthesis by Nitrate Dissimilating Bacteria in Carbonatogenesis Process under Aerobic and Anaerobic Conditions. Geomicrobiology Journal 2021; 38:791-808. [DOI: 10.1080/01490451.2021.1951398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 06/29/2021] [Indexed: 09/02/2023]
Affiliation(s)
- Marwa Eltarahony
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
| | - Sahar Zaki
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
| | - Ayman Kamal
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
- Faculty of Agriculture, Alexandria University, Alexandria, Egypt
| | - Desouky Abd-El-Haleem
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
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13
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Mickoleit F, Rosenfeldt S, Toro-Nahuelpan M, Schaffer M, Schenk AS, Plitzko JM, Schüler D. High-Yield Production, Characterization, and Functionalization of Recombinant Magnetosomes in the Synthetic Bacterium Rhodospirillum rubrum "magneticum". Adv Biol (Weinh) 2021; 5:e2101017. [PMID: 34296829 DOI: 10.1002/adbi.202101017] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/10/2021] [Indexed: 01/02/2023]
Abstract
Recently, the photosynthetic Rhodospirillum rubrum has been endowed with the ability of magnetosome biosynthesis by transfer and expression of biosynthetic gene clusters from the magnetotactic bacterium Magnetospirillum gryphiswaldense. However, the growth conditions for efficient magnetite biomineralization in the synthetic R. rubrum "magneticum", as well as the particles themselves (i.e., structure and composition), have so far not been fully characterized. In this study, different cultivation strategies, particularly the influence of temperature and light intensity, are systematically investigated to achieve optimal magnetosome biosynthesis. Reduced temperatures ≤16 °C and gradual increase in light intensities favor magnetite biomineralization at high rates, suggesting that magnetosome formation might utilize cellular processes, cofactors, and/or pathways that are linked to photosynthetic growth. Magnetosome yields of up to 13.6 mg magnetite per liter cell culture are obtained upon photoheterotrophic large-scale cultivation. Furthermore, it is shown that even more complex, i.e., oligomeric, catalytically active functional moieties like enzyme proteins can be efficiently expressed on the magnetosome surface, thereby enabling the in vivo functionalization by genetic engineering. In summary, it is demonstrated that the synthetic R. rubrum "magneticum" is a suitable host for high-yield magnetosome biosynthesis and the sustainable production of genetically engineered, bioconjugated magnetosomes.
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Affiliation(s)
- Frank Mickoleit
- Dept. Microbiology, University of Bayreuth, D-95447, Bayreuth, Germany
| | - Sabine Rosenfeldt
- Bavarian Polymer Institute (BPI)/Physical Chemistry 1, University of Bayreuth, D-95447, Bayreuth, Germany
| | - Mauricio Toro-Nahuelpan
- Dept. Microbiology, University of Bayreuth, D-95447, Bayreuth, Germany.,Dept. Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152, Martinsried, Germany
| | - Miroslava Schaffer
- Dept. Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152, Martinsried, Germany
| | - Anna S Schenk
- Bavarian Polymer Institute (BPI)/Physical Chemistry - Colloidal Systems, University of Bayreuth, D-95447, Bayreuth, Germany
| | - Jürgen M Plitzko
- Dept. Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152, Martinsried, Germany
| | - Dirk Schüler
- Dept. Microbiology, University of Bayreuth, D-95447, Bayreuth, Germany
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14
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Asamoto CK, Rempfert KR, Luu VH, Younkin AD, Kopf SH. Enzyme-Specific Coupling of Oxygen and Nitrogen Isotope Fractionation of the Nap and Nar Nitrate Reductases. Environ Sci Technol 2021; 55:5537-5546. [PMID: 33687201 DOI: 10.1021/acs.est.0c07816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Dissimilatory nitrate reduction (DNR) to nitrite is the first step in denitrification, the main process through which bioavailable nitrogen is removed from ecosystems. DNR is catalyzed by both cytosolic (Nar) and periplasmic (Nap) nitrate reductases and fractionates the stable isotopes of nitrogen (14N, 15N) and oxygen (16O, 18O), which is reflected in residual environmental nitrate pools. Data on the relationship between the pattern in oxygen vs nitrogen isotope fractionation (18ε/15ε) suggests that systematic differences exist between marine and terrestrial ecosystems that are not fully understood. We examined the 18ε/15ε of nitrate-reducing microorganisms that encode Nar, Nap, or both enzymes, as well as gene deletion mutants of Nar and Nap to test the hypothesis that enzymatic differences alone could explain the environmental observations. We find that the distribution of 18ε/15ε fractionation ratios of all examined nitrate reductases forms two distinct peaks centered around an 18ε/15ε proportionality of 0.55 (Nap) and 0.91 (Nar), with the notable exception of the Bacillus Nar reductases, which cluster isotopically with the Nap reductases. Our findings may explain differences in 18ε/15ε fractionation between marine and terrestrial systems and challenge current knowledge about Nar 18ε/15ε signatures.
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Affiliation(s)
- Ciara K Asamoto
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Kaitlin R Rempfert
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Victoria H Luu
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
| | - Adam D Younkin
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Sebastian H Kopf
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
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15
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Liu P, Tamaxia A, Liu Y, Qiu H, Pan J, Jin Z, Zhao X, Roberts AP, Pan Y, Li J. Identification and characterization of magnetotactic Gammaproteobacteria from a salt evaporation pool, Bohai Bay, China. Environ Microbiol 2021; 24:938-950. [PMID: 33876543 DOI: 10.1111/1462-2920.15516] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/27/2021] [Accepted: 04/06/2021] [Indexed: 11/27/2022]
Abstract
Magnetotactic bacteria (MTB) are phylogenetically diverse prokaryotes that can produce intracellular chain-assembled nanocrystals of magnetite (Fe3 O4 ) or greigite (Fe3 S4 ). Compared with their wide distribution in the Alpha-, Eta- and Delta-proteobacteria classes, few MTB strains have been identified in the Gammaproteobacteria class, resulting in limited knowledge of bacterial diversity and magnetosome biomineralization within this phylogenetic branch. Here, we identify two magnetotactic Gammaproteobacteria strains (tentatively named FZSR-1 and FZSR-2 respectively) from a salt evaporation pool in Bohai Bay, at the Fuzhou saltern, Dalian City, eastern China. Phylogenetic analysis indicates that strain FZSR-2 is the same species as strains SHHR-1 and SS-5, which were discovered previously from brackish and hypersaline environments respectively. Strain FZSR-1 represents a novel species. Compared with strains FZSR-2, SHHR-1 and SS-5 in which magnetite particles are assembled into a single chain, FZSR-1 cells form relatively narrower magnetite nanoparticles that are often organized into double chains. We find a good relationship between magnetite morphology within strains FZSR-2, SHHR-1 and SS-5 and the salinity of the environment in which they live. This study expands the bacterial diversity of magnetotactic Gammaproteobacteria and provides new insights into magnetosome biomineralization within magnetotactic Gammaproteobacteria.
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Affiliation(s)
- Peiyu Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Alima Tamaxia
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hao Qiu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juntong Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhongke Jin
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiang Zhao
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Andrew P Roberts
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Yongxin Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinhua Li
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China.,Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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16
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He C, Zhang B, Lu J, Qiu R. A newly discovered function of nitrate reductase in chemoautotrophic vanadate transformation by natural mackinawite in aquifer. Water Res 2021; 189:116664. [PMID: 33249309 DOI: 10.1016/j.watres.2020.116664] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
Mackinawite (FeS), a widely-distributed natural reducing mineral, can donate electron for various (bio)processes. However, little is known about mackinawite-driven chemoautotrophic bioreduction of toxic vanadate [V(V)] in aquifer. This study demonstrates that V(V) is successfully bioreduced by mackinawite under anaerobic condition via 150-d operation of constructed aquifer. Complete V(V) removal was achieved at the initial concentration of 10 mg/L and flow rate of 0.125 mL/min. Fluctuant hydrochemistry and hydrodynamics affected V(V) removal performance. Biotic activity was identified as the major contribution to V(V) transformation (76.4 ± 1.01%). Chemoautotrophic genera (e.g., Thiobacillus) could oxidize FeS coupled to direct V(V) reduction independently. Heterotrophic V(V) reducers (e.g., Pseudomonas and Spirochaeta) could also achieve V(V) detoxification by utilizing metabolic intermediates synthesized by autotrophic Fe(II) oxidizers (e.g., Thiobacillus) and S(-II) oxidizing genera (e.g., Sulfuricurvum). Gene abundance and enzymatic activity tests confirmed that nitrate reductase gene napA functioned crucially in chemoautotrophic V(V) reduction by Fe(II) and S(-II) donating electron. V(V) was reduced to insoluble V(IV) while elements in mackinawite were oxidized to Fe(III) and SO42-. This study reveals the coupling of iron, sulfur and vanadium in biogeochemical cycling, and offers a promising strategy for remediation of V(V)-polluted aquifer.
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Affiliation(s)
- Chao He
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Baogang Zhang
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China.
| | - Jianping Lu
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Rui Qiu
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China
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17
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Orcutt BN, D'Angelo T, Wheat CG, Trembath‐Reichert E. Microbe‐mineral biogeography from multi‐year incubations in oceanic crust at North Pond,
Mid‐Atlantic
Ridge. Environ Microbiol 2021; 23:3923-3936. [DOI: 10.1111/1462-2920.15366] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/16/2020] [Accepted: 12/16/2020] [Indexed: 01/04/2023]
Affiliation(s)
- Beth N. Orcutt
- Bigelow Laboratory for Ocean Sciences East Boothbay ME 04544 USA
- Hanse‐Wissenschaftskolleg Delmenhorst Germany
| | - Timothy D'Angelo
- Bigelow Laboratory for Ocean Sciences East Boothbay ME 04544 USA
| | - C. Geoff Wheat
- Institute of Marine Sciences, College of Fisheries and Ocean Sciences University of Alaska Moss Landing CA 95039 USA
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18
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Niu W, Zhang Y, Liu J, Wen T, Miao T, Basit A, Jiang W. OxyR controls magnetosome formation by regulating magnetosome island (MAI) genes, iron metabolism, and redox state. Free Radic Biol Med 2020; 161:272-282. [PMID: 33075503 DOI: 10.1016/j.freeradbiomed.2020.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 12/25/2022]
Abstract
Magnetospirillum gryphiswaldense MSR-1 uses chains of magnetosomes, membrane-enveloped magnetite (Fe(II)Fe(III)2O4) nanocrystals, to align along magnetic field. The process of magnetosome biomineralization requires a precise biological control of redox conditions to maintain a balanced amounts of ferric and ferrous iron. Here, we identified functions of the global regulator OxyR (MGMSRv2_4250, OxyR-4250) in MSR-1 during magnetosome formation. OxyR deletion mutant ΔoxyR-4250 displayed reduced magnetic response, and increased levels of intracellular ROS (reactive oxygen species). OxyR-4250 protein upregulated expression of six antioxidant genes (ahpC1, ahpC2, katE, katG, sodB, trxA), four iron metabolism-related regulator genes (fur, irrA, irrB, irrC), a bacterioferritin gene (bfr), and a DNA protection gene (dps). OxyR-4250 was shown, for the first time, to directly regulate magnetosome island (MAI) genes mamGFDC, mamXY, and feoAB1 operons. Taken together, our findings indicate that OxyR-4250 helps maintain a proper redox environment for magnetosome formation by eliminating excess ROS, regulating iron homeostasis and participating in regulation of Fe2+/Fe3+ ratio within the magnetosome vesicle through regulating MAI genes.
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Affiliation(s)
- Wei Niu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yunpeng Zhang
- Agricultural Utilization Research Center, Nutrition and Health Research Institute, COFCO Corporation, Beijing, 102209, China
| | - Junquan Liu
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Tong Wen
- Department of Biology Science and Technology, Baotou Teacher's College, Baotou, 014030, China
| | - Ting Miao
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Abdul Basit
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wei Jiang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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19
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Silva KT, Schüler M, Mickoleit F, Zwiener T, Müller FD, Awal RP, Weig A, Brachmann A, Uebe R, Schüler D. Genome-Wide Identification of Essential and Auxiliary Gene Sets for Magnetosome Biosynthesis in Magnetospirillum gryphiswaldense. mSystems 2020; 5:e00565-20. [PMID: 33203687 DOI: 10.1128/mSystems.00565-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Magnetospirillum gryphiswaldense is one of the few tractable model magnetotactic bacteria (MTB) for studying magnetosome biomineralization. So far, knowledge on the genetic determinants of this complex process has been mainly gathered using reverse genetics and candidate approaches. In contrast, nontargeted forward genetics studies are lacking, since application of such techniques in MTB has been complicated for a number of technical reasons. Here, we report on the first comprehensive transposon mutagenesis study in MTB, aiming at systematic identification of auxiliary genes necessary to support magnetosome formation in addition to key genes harbored in the magnetosome island (MAI). Our work considerably extends the candidate set of novel subsidiary determinants and shows that the full gene complement underlying magnetosome biosynthesis is larger than assumed. In particular, we were able to define certain cellular pathways as specifically important for magnetosome formation that have not been implicated in this process so far. Magnetotactic bacteria (MTB) stand out by their ability to manufacture membrane-enclosed magnetic organelles, so-called magnetosomes. Previously, it has been assumed that a genomic region of approximately 100 kbp, the magnetosome island (MAI), harbors all genetic determinants required for this intricate biosynthesis process. Recent evidence, however, argues for the involvement of additional auxiliary genes that have not been identified yet. In the present study, we set out to delineate the full gene complement required for magnetosome production in the alphaproteobacterium Magnetospirillum gryphiswaldense using a systematic genome-wide transposon mutagenesis approach. By an optimized procedure, a Tn5 insertion library of 80,000 clones was generated and screened, yielding close to 200 insertants with mild to severe impairment of magnetosome biosynthesis. Approximately 50% of all Tn5 insertion sites mapped within the MAI, mostly leading to a nonmagnetic phenotype. In contrast, in the majority of weakly magnetic Tn5 insertion mutants, genes outside the MAI were affected, which typically caused lower numbers of magnetite crystals with partly aberrant morphology, occasionally combined with deviant intracellular localization. While some of the Tn5-struck genes outside the MAI belong to pathways that have been linked to magnetosome formation before (e.g., aerobic and anaerobic respiration), the majority of affected genes are involved in so far unsuspected cellular processes, such as sulfate assimilation, oxidative protein folding, and cytochrome c maturation, or are altogether of unknown function. We also found that signal transduction and redox functions are enriched in the set of Tn5 hits outside the MAI, suggesting that such processes are particularly important in support of magnetosome biosynthesis. IMPORTANCEMagnetospirillum gryphiswaldense is one of the few tractable model magnetotactic bacteria (MTB) for studying magnetosome biomineralization. So far, knowledge on the genetic determinants of this complex process has been mainly gathered using reverse genetics and candidate approaches. In contrast, nontargeted forward genetics studies are lacking, since application of such techniques in MTB has been complicated for a number of technical reasons. Here, we report on the first comprehensive transposon mutagenesis study in MTB, aiming at systematic identification of auxiliary genes necessary to support magnetosome formation in addition to key genes harbored in the magnetosome island (MAI). Our work considerably extends the candidate set of novel subsidiary determinants and shows that the full gene complement underlying magnetosome biosynthesis is larger than assumed. In particular, we were able to define certain cellular pathways as specifically important for magnetosome formation that have not been implicated in this process so far.
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20
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Riese CN, Uebe R, Rosenfeldt S, Schenk AS, Jérôme V, Freitag R, Schüler D. An automated oxystat fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense. Microb Cell Fact 2020; 19:206. [PMID: 33168043 PMCID: PMC7654035 DOI: 10.1186/s12934-020-01469-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/29/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Magnetosomes produced by magnetotactic bacteria represent magnetic nanoparticles with unprecedented characteristics. However, their use in many biotechnological applications has so far been hampered by their challenging bioproduction at larger scales. RESULTS Here, we developed an oxystat batch fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense in a 3 L bioreactor. An automated cascade regulation enabled highly reproducible growth over a wide range of precisely controlled oxygen concentrations (1-95% of air saturation). In addition, consumption of lactate as the carbon source and nitrate as alternative electron acceptor were monitored during cultivation. While nitrate became growth limiting during anaerobic growth, lactate was the growth limiting factor during microoxic cultivation. Analysis of microoxic magnetosome biomineralization by cellular iron content, magnetic response, transmission electron microscopy and small-angle X-ray scattering revealed magnetosomal magnetite crystals were highly uniform in size and shape. CONCLUSION The fermentation regime established in this study facilitates stable oxygen control during culturing of Magnetospirillum gryphiswaldense. Further scale-up seems feasible by combining the stable oxygen control with feeding strategies employed in previous studies. Results of this study will facilitate the highly reproducible laboratory-scale bioproduction of magnetosomes for a diverse range of future applications in the fields of biotechnology and biomedicine.
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Affiliation(s)
- Cornelius N Riese
- Department of Microbiology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - René Uebe
- Department of Microbiology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Sabine Rosenfeldt
- Physical Chemistry I, University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany
- Bavarian Polymer Institute (BPI), University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany
| | - Anna S Schenk
- Bavarian Polymer Institute (BPI), University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany
- Physical Chemistry - Colloidal Systems, University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany
| | - Valérie Jérôme
- Chair for Process Biotechnology, University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany
| | - Ruth Freitag
- Chair for Process Biotechnology, University of Bayreuth, Universitätsstraße 30, Bayreuth, 95447, Germany.
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany.
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21
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Abstract
Magnetotactic bacteria are aquatic or sediment-dwelling microorganisms able to take advantage of the Earth's magnetic field for directed motility. The source of this amazing trait is magnetosomes, unique organelles used to synthesize single nanometer-sized crystals of magnetic iron minerals that are queued up to build an intracellular compass. Most of these microorganisms cannot be cultivated under controlled conditions, much less genetically engineered, with only few exceptions. However, two of the genetically amenable Magnetospirillum species have emerged as tractable model organisms to study magnetosome formation and magnetotaxis. Recently, much has been revealed about the process of magnetosome biogenesis and dedicated structures for magnetosome dynamics and positioning, which suggest an unexpected cellular intricacy of these organisms. In this minireview, we summarize new insights and place the molecular mechanisms of magnetosome formation in the context of the complex cell biology of Magnetospirillum spp. First, we provide an overview on magnetosome vesicle synthesis and magnetite biomineralization, followed by a discussion of the perceptions of dynamic organelle positioning and its biological implications, which highlight that magnetotactic bacteria have evolved sophisticated mechanisms to construct, incorporate, and inherit a unique navigational device. Finally, we discuss the impact of magnetotaxis on motility and its interconnection with chemotaxis, showing that magnetotactic bacteria are outstandingly adapted to lifestyle and habitat.
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22
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Monteil CL, Grouzdev DS, Perrière G, Alonso B, Rouy Z, Cruveiller S, Ginet N, Pignol D, Lefevre CT. Repeated horizontal gene transfers triggered parallel evolution of magnetotaxis in two evolutionary divergent lineages of magnetotactic bacteria. ISME J 2020; 14:1783-1794. [PMID: 32296121 PMCID: PMC7305187 DOI: 10.1038/s41396-020-0647-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/21/2020] [Accepted: 03/24/2020] [Indexed: 12/27/2022]
Abstract
Under the same selection pressures, two genetically divergent populations may evolve in parallel toward the same adaptive solutions. Here, we hypothesized that magnetotaxis (i.e., magnetically guided chemotaxis) represents a key adaptation to micro-oxic habitats in aquatic sediments and that its parallel evolution homogenized the phenotypes of two evolutionary divergent clusters of freshwater spirilla. All magnetotactic bacteria affiliated to the Magnetospirillum genus (Alphaproteobacteria class) biomineralize the same magnetic particle chains and share highly similar physiological and ultrastructural features. We looked for the processes that could have contributed at shaping such an evolutionary pattern by reconciling species and gene trees using newly sequenced genomes of Magnetospirillum related bacteria. We showed that repeated horizontal gene transfers and homologous recombination of entire operons contributed to the parallel evolution of magnetotaxis. We propose that such processes could represent a more parsimonious and rapid solution for adaptation compared with independent and repeated de novo mutations, especially in the case of traits as complex as magnetotaxis involving tens of interacting proteins. Besides strengthening the idea about the importance of such a function in micro-oxic habitats, these results reinforce previous observations in experimental evolution suggesting that gene flow could alleviate clonal interference and speed up adaptation under some circumstances.
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Affiliation(s)
- Caroline L Monteil
- Aix-Marseille University, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille, Saint Paul lez Durance, France.
| | - Denis S Grouzdev
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Guy Perrière
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR5558, Université Claude Bernard - Lyon 1, 69622, Villeurbanne, France
| | - Béatrice Alonso
- Aix-Marseille University, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille, Saint Paul lez Durance, France
| | - Zoé Rouy
- LABGeM, Genomique Metabolique, CEA, Genoscope, Institut Francois Jacob, CNRS, Universite d'Evry, Universite Paris-Saclay, Evry, France
| | - Stéphane Cruveiller
- LABGeM, Genomique Metabolique, CEA, Genoscope, Institut Francois Jacob, CNRS, Universite d'Evry, Universite Paris-Saclay, Evry, France
| | - Nicolas Ginet
- Aix Marseille University, CNRS, LCB, Marseille, France
| | - David Pignol
- Aix-Marseille University, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille, Saint Paul lez Durance, France
| | - Christopher T Lefevre
- Aix-Marseille University, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille, Saint Paul lez Durance, France.
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Dziuba MV, Zwiener T, Uebe R, Schüler D. Single-step transfer of biosynthetic operons endows a non-magnetotactic Magnetospirillum strain from wetland with magnetosome biosynthesis. Environ Microbiol 2020; 22:1603-1618. [PMID: 32079043 DOI: 10.1111/1462-2920.14950] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/03/2020] [Accepted: 02/18/2020] [Indexed: 11/28/2022]
Abstract
The magnetotactic lifestyle represents one of the most complex traits found in many bacteria from aquatic environments and depends on magnetic organelles, the magnetosomes. Genetic transfer of magnetosome biosynthesis operons to a non-magnetotactic bacterium has only been reported once so far, but it is unclear whether this may also occur in other recipients. Besides magnetotactic species from freshwater, the genus Magnetospirillum of the Alphaproteobacteria also comprises a number of strains lacking magnetosomes, which are abundant in diverse microbial communities. Their close phylogenetic interrelationships raise the question whether the non-magnetotactic magnetospirilla may have the potential to (re)gain a magnetotactic lifestyle upon acquisition of magnetosome gene clusters. Here, we studied the transfer of magnetosome gene operons into several non-magnetotactic environmental magnetospirilla. Single-step transfer of a compact vector harbouring >30 major magnetosome genes from M. gryphiswaldense induced magnetosome biosynthesis in a Magnetospirillum strain from a constructed wetland. However, the resulting magnetic cellular alignment was insufficient for efficient magnetotaxis under conditions mimicking the weak geomagnetic field. Our work provides insights into possible evolutionary scenarios and potential limitations for the dissemination of magnetotaxis by horizontal gene transfer and expands the range of foreign recipients that can be genetically magnetized.
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Affiliation(s)
- Marina V Dziuba
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany.,Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Theresa Zwiener
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Rene Uebe
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
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Eltarahony M, Zaki S, Abd-El-Haleem D. Aerobic and anaerobic removal of lead and mercury via calcium carbonate precipitation mediated by statistically optimized nitrate reductases. Sci Rep 2020; 10:4029. [PMID: 32132620 DOI: 10.1038/s41598-020-60951-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/11/2020] [Indexed: 01/18/2023] Open
Abstract
The nonbiodegradability nature of heavy metals renders them resident in food chain and subsequently, destructing the entire ecosystem. Therefore, this study aimed to employ nitrate reduction-driven calcium carbonate precipitation in remediation of lead and mercury aerobically and anaerobically by Proteus mirabilis 10B, for the first time. Initially, Plackett-Burman design was employed to screen of 16 independent variables for their significances on periplasmic (NAP) and membrane-bound (NAR) nitrate reductases. The levels for five significant variables and their interaction effects were further optimized by central composite design. The maximum activities of NAP and NAR recorded 2450 and 3050 U/mL by 2-fold enhancement, comparing with non-optimized medium. Under aerobic and anaerobic optimized remediation conditions, the changes in media chemistry revealed positive correlation among bacterial growth, nitrate reductase activity, pH, NO3- and NO2- consumption and removal of Ca2+, Pb2+ and Hg2+. Subsequently, the remediated precipitates were subjected to mineralogical analysis; energy dispersive X-ray patterns exhibited characteristic peaks of C, O and Ca in addition to Pb and Hg. Scanning electron microscope depicted the presence of bacterial imprints and protrusions on rough and smooth surface bioliths. However, X-ray diffraction indicated entrapment of PbCO3, Pb2O, CaPbO3, Hg and Hg2O in calcite lattice. Interestingly, such approach is feasible, efficient, cost-effective and ecofriendly for heavy metals remediation.
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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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Pfeiffer D, Schüler D. Quantifying the Benefit of a Dedicated "Magnetoskeleton" in Bacterial Magnetotaxis by Live-Cell Motility Tracking and Soft Agar Swimming Assay. Appl Environ Microbiol 2020; 86:e01976-19. [PMID: 31732570 DOI: 10.1128/AEM.01976-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022] Open
Abstract
The alphaproteobacterium Magnetospirillum gryphiswaldense has the intriguing ability to navigate within magnetic fields, a behavior named magnetotaxis, governed by the formation of magnetosomes, intracellular membrane-enveloped crystals of magnetite. Magnetosomes are aligned in chains along the cell's motility axis by a dedicated multipart cytoskeleton ("magnetoskeleton"); however, precise estimates of its significance for magnetotaxis have not been reported. Here, we estimated the alignment of strains deficient in various magnetoskeletal constituents by live-cell motility tracking within defined magnetic fields ranging from 50 μT (reflecting the geomagnetic field) up to 400 μT. Motility tracking revealed that ΔmamY and ΔmamK strains (which assemble mispositioned and fragmented chains, respectively) are partially impaired in magnetotaxis, with approximately equal contributions of both proteins. This impairment was reflected by a required magnetic field strength of 200 μT to achieve a similar degree of alignment as for the wild-type strain in a 50-μT magnetic field. In contrast, the ΔmamJ strain, which predominantly forms clusters of magnetosomes, was only weakly aligned under any of the tested field conditions and could barely be distinguished from a nonmagnetic mutant. Most findings were corroborated by a soft agar swimming assay to analyze magnetotaxis based on the degree of distortion of swim halos formed in magnetic fields. Motility tracking further revealed that swimming speeds of M. gryphiswaldense are highest within the field strength equaling the geomagnetic field. In conclusion, magnetic properties and intracellular positioning of magnetosomes by a dedicated magnetoskeleton are required and optimized for bacterial magnetotaxis and most efficient locomotion within the geomagnetic field.IMPORTANCE In Magnetospirillum gryphiswaldense, magnetosomes are aligned in quasi-linear chains in a helical cell by a complex cytoskeletal network, including the actin-like MamK and adapter MamJ for magnetosome chain concatenation and segregation and MamY to position magnetosome chains along the shortest cellular axis of motility. Magnetosome chain positioning is assumed to be required for efficient magnetic navigation; however, the significance and contribution of all key constituents have not been quantified within defined and weak magnetic fields reflecting the geomagnetic field. Employing two different motility-based methods to consider the flagellum-mediated propulsion of cells, we depict individual benefits of all magnetoskeletal constituents for magnetotaxis. Whereas lack of mamJ resulted almost in an inability to align cells in weak magnetic fields, an approximately 4-fold-increased magnetic field strength was required to compensate for the loss of mamK or mamY In summary, the magnetoskeleton and optimal positioning of magnetosome chains are required for efficient magnetotaxis.
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Wu YW, Yang SH, Hwangbo M, Chu KH. Analysis of Zobellella denitrificans ZD1 draft genome: Genes and gene clusters responsible for high polyhydroxybutyrate (PHB) production from glycerol under saline conditions and its CRISPR-Cas system. PLoS One 2019; 14:e0222143. [PMID: 31513626 PMCID: PMC6742469 DOI: 10.1371/journal.pone.0222143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/22/2019] [Indexed: 01/25/2023] Open
Abstract
Polyhydroxybutyrate (PHB) is biodegradable and renewable and thus considered as a promising alternative to petroleum-based plastics. However, PHB production is costly due to expensive carbon sources for culturing PHB-accumulating microorganisms under sterile conditions. We discovered a hyper PHB-accumulating denitrifying bacterium, Zobellella denitrificans ZD1 (referred as strain ZD1 hereafter) capable of using non-sterile crude glycerol (a waste from biodiesel production) and nitrate to produce high PHB yield under saline conditions. Nevertheless, the underlying genetic mechanisms of PHB production in strain ZD1 have not been elucidated. In this study, we discovered a complete pathway of glycerol conversion to PHB, a novel PHB synthesis gene cluster, a salt-tolerant gene cluster, denitrifying genes, and an assimilatory nitrate reduction gene cluster in the ZD1 genome. Interestingly, the novel PHB synthesis gene cluster was found to be conserved among marine Gammaproteobacteria. Higher levels of PHB accumulation were linked to higher expression levels of the PHB synthesis gene cluster in ZD1 grown with glycerol and nitrate under saline conditions. Additionally, a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas type-I-E antiviral system was found in the ZD1 genome along with a long spacer list, in which most of the spacers belong to either double-stranded DNA viruses or unknown phages. The results of the genome analysis revealed strain ZD1 used the novel PHB gene cluster to produce PHB from non-sterile crude glycerol under saline conditions.
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Affiliation(s)
- Yu-Wei Wu
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
- Clinical Big Data Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Shih-Hung Yang
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, United States of America
| | - Myung Hwangbo
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, United States of America
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, United States of America
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Zaki SA, Eltarahony MM, Abd-El-Haleem DA. Disinfection of water and wastewater by biosynthesized magnetite and zerovalent iron nanoparticles via NAP-NAR enzymes of Proteus mirabilis 10B. Environ Sci Pollut Res Int 2019; 26:23661-23678. [PMID: 31201708 DOI: 10.1007/s11356-019-05479-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Disinfection of water and wastewater strongly contributes to solving the problem of water shortage in arid/semi-arid areas; cheap and ecofriendly approaches have to be used to meet water quality standards. In the present study, a green synthesis of iron nanoparticles (INPs) under aerobic and anaerobic conditions via nitrate reductases (NAP/NAR) enzymes produced by Proteus mirabilis strain 10B were employed for this target. The biosynthesized INPs were characterized; UV-Vis spectroscopy revealed surface plasmon resonance at 410 (aerobic) and 265 nm (anaerobic). XRD indicated crystalline magnetite ((MNPs) aerobically synthesized) and zerovalent INPs (ZVINPs anaerobically synthesized). EDX demonstrated strong iron signal with atomic percentages 73.3% (MNPs) and 61.7% (ZVINPs). TEM micrographs illustrated tiny, spherical, periplasmic MNPs (1.44-1.92 nm) and cytoplasmic ZVINPs with 11.7-60.8 nm. Zeta potential recorded - 31.8 mV (ZVINPs) and - 66.4 mV (MNPs) affirming colloidal stability. Moreover, the disinfection power of INPs was evaluated for standards organisms and real water (fresh, sea and salt mine) and wastewater (municipal, agricultural and industrial) samples. The results reported that INPs displayed higher antagonistic effect than iron precursor, 700 and 850 μg/mL of MNPs and ZVINPs, respectively, was sufficient to show a drastic algicidal effect on algal growth. Both types of INPs demonstrated obvious dose-dependent antibiofilm efficiency. Due to their smaller size, MNPs were more efficient than ZVINPs at the suppression of microbial growth in all examined water samples. Overall, MNPs showed superior antagonistic activity, which promotes their exploitation in enhancing water/wastewater quality.
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Affiliation(s)
- Sahar A Zaki
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934, New Borg El-Arab City, Alexandria, Egypt.
| | - Marwa Moustafa Eltarahony
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934, New Borg El-Arab City, Alexandria, Egypt
| | - Desouky A Abd-El-Haleem
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934, New Borg El-Arab City, Alexandria, Egypt
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Wang X, Zheng H, Wang Q, Jiang W, Wen Y, Tian J, Sun J, Li Y, Li J. Novel Protein Mg2046 Regulates Magnetosome Synthesis in Magnetospirillum gryphiswaldense MSR-1 by Modulating a Proper Redox Status. Front Microbiol 2019; 10:1478. [PMID: 31297108 PMCID: PMC6607277 DOI: 10.3389/fmicb.2019.01478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 06/13/2019] [Indexed: 11/13/2022] Open
Abstract
Magnetotactic bacteria (MTB) are a large, polyphyletic group of aquatic microorganisms capable of absorbing large amounts of iron and synthesizing intercellular nano-scaled nanoparticles termed magnetosomes. In our previous transcriptomic studies, we discovered that a novel gene (MGMSRv2_2046, termed as mg2046) in Magnetospirillum gryphiswaldense strain MSR-1 was significantly up-regulated during the period of magnetosome synthesis. In the present study, we constructed a MSR-1 mutant strain with deletion of mg2046 (termed Δmg2046) in order to evaluate the role of this gene in cell physiological status and magnetosome formation process. In comparison with wild-type MSR-1, Δmg2046 showed similar cell growth, but much lower cell magnetic response, smaller number and size of magnetosomes, and reduced iron absorption ability. mg2046 deletion evidently disrupted iron uptake, and redox equilibrium, and strongly inhibited transcription of dissimilatory denitrification pathway genes. Our experimental findings, taken together with results of gene homology analysis, indicate that Mg2046 acts as a positive regulator in MSR-1 under microaerobic conditions, responding to hypoxia signals and participating in regulation of oxygen metabolism, in part as a co-regulator of dissimilatory denitrification pathway with oxygen sensor MgFnr (MGMSRv2_2946, termed as Mg2946). Mg2046 is clearly involved in coupled regulation of cellular oxygen, iron and nitrogen metabolism under micro-aerobic or anaerobic conditions. Our findings help explain how MSR-1 cells initiate dissimilatory denitrification pathway and overcome energy deficiency under microaerobic conditions, and have broader implications regarding bacterial survival and energy metabolism strategies under hypoxia.
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Affiliation(s)
- Xu Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China.,Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Haolan Zheng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qing Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Wei Jiang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ying Wen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jiesheng Tian
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jianbo Sun
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Ying Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jilun Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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Fuduche M, Davidson S, Boileau C, Wu LF, Combet-Blanc Y. A Novel Highly Efficient Device for Growing Micro-Aerophilic Microorganisms. Front Microbiol 2019; 10:534. [PMID: 31001208 PMCID: PMC6434946 DOI: 10.3389/fmicb.2019.00534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/01/2019] [Indexed: 11/13/2022] Open
Abstract
This work describes a novel, simple and cost-effective culture system, named the Micro-Oxygenated Culture Device (MOCD), designed to grow microorganisms under particularly challenging oxygenation conditions. Two microaerophilic magnetotactic bacteria, a freshwater Magnetospirillum gryphiswaldense strain MSR-1 and a marine Magnetospira sp. strain QH-2, were used as biological models to prove the efficiency of the MOCD and to evaluate its specifications. Using the MOCD, growth rates of MSR-1 and QH-2 increased by four and twofold, respectively, when compared to traditional growing techniques using simple bottles. Oxystat-bioreactors have been typically used and specifically designed to control low dissolved oxygen concentrations, however, the MOCD, which is far less sophisticated was proven to be as efficient for both MSR-1 and QH-2 cultures with regard to growth rate, and even better for MSR-1 when looking at cell yield (70% increase). The MOCD enables a wide range of oxygenation conditions to be studied, including different O2-gradients. This makes it an innovative and ingenious culture device that opens up new parameters for growing microaerobic microorganisms.
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Affiliation(s)
- Maxime Fuduche
- Aix Marseille University, IRD, CNRS, Université de Toulon, Marseille, France
| | - Sylvain Davidson
- Aix Marseille University, IRD, CNRS, Université de Toulon, Marseille, France
| | - Céline Boileau
- Aix Marseille University, IRD, CNRS, Université de Toulon, Marseille, France
| | - Long-Fei Wu
- Aix Marseille University, CNRS, LCB, Marseille, France
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Mickoleit F, Schüler D. Generation of nanomagnetic biocomposites by genetic engineering of bacterial magnetosomes. Bioinspired, Biomimetic and Nanobiomaterials 2019. [DOI: 10.1680/jbibn.18.00005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Frank Mickoleit
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
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Camejo PY, Oyserman BO, McMahon KD, Noguera DR. Integrated Omic Analyses Provide Evidence that a " Candidatus Accumulibacter phosphatis" Strain Performs Denitrification under Microaerobic Conditions. mSystems 2019; 4:e00193-18. [PMID: 30944872 DOI: 10.1128/mSystems.00193-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/13/2018] [Indexed: 11/20/2022] Open
Abstract
The ability of "Candidatus Accumulibacter phosphatis" to grow and remove phosphorus from wastewater under cycling anaerobic and aerobic conditions has also been investigated as a metabolism that could lead to simultaneous removal of nitrogen and phosphorus by a single organism. However, although phosphorus removal under cyclic anaerobic and anoxic conditions has been demonstrated, clarifying the role of "Ca. Accumulibacter phosphatis" in this process has been challenging, since (i) experimental research describes contradictory findings, (ii) none of the published "Ca. Accumulibacter phosphatis" genomes show the existence of a complete respiratory pathway for denitrification, and (iii) some genomes lacking a complete respiratory pathway have genes for assimilatory nitrate reduction. In this study, we used an integrated omics analysis to elucidate the physiology of a "Ca. Accumulibacter phosphatis" strain enriched in a reactor operated under cyclic anaerobic and microaerobic conditions. The reactor's performance suggested the ability of the enriched "Ca. Accumulibacter phosphatis" strain (clade IC) to simultaneously use oxygen and nitrate as electron acceptors under microaerobic conditions. A draft genome of this organism was assembled from metagenomic reads ("Ca. Accumulibacter phosphatis" UW-LDO-IC) and used as a reference to examine transcript abundance throughout one reactor cycle. The genome of UW-LDO-IC revealed the presence of a full pathway for respiratory denitrification. The observed transcript abundance patterns showed evidence of coregulation of the denitrifying genes along with a cbb 3 cytochrome, which has been characterized as having high affinity for oxygen. Furthermore, we identified an FNR-like binding motif upstream of the coregulated genes, suggesting transcription-level regulation of both denitrifying and respiratory pathways in UW-LDO-IC. Taking the results together, the omics analysis provides strong evidence that "Ca. Accumulibacter phosphatis" UW-LDO-IC uses oxygen and nitrate simultaneously as electron acceptors under microaerobic conditions. IMPORTANCE "Candidatus Accumulibacter phosphatis" is widely found in full-scale wastewater treatment plants, where it has been identified as the key organism for biological removal of phosphorus. Since aeration can account for 50% of the energy use during wastewater treatment, microaerobic conditions for wastewater treatment have emerged as a cost-effective alternative to conventional biological nutrient removal processes. Our report provides strong genomics-based evidence not only that "Ca. Accumulibacter phosphatis" is the main organism contributing to phosphorus removal under microaerobic conditions but also that this organism simultaneously respires nitrate and oxygen in this environment, consequently removing nitrogen and phosphorus from the wastewater. Such activity could be harnessed in innovative designs for cost-effective and energy-efficient optimization of wastewater treatment systems.
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Fernández-Castané A, Li H, Thomas ORT, Overton TW. Development of a simple intensified fermentation strategy for growth of Magnetospirillum gryphiswaldense MSR-1: Physiological responses to changing environmental conditions. N Biotechnol 2018; 46:22-30. [PMID: 29864580 PMCID: PMC6109776 DOI: 10.1016/j.nbt.2018.05.1201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 02/05/2023]
Abstract
Magnetosomes are natural intracellular, membrane-bound, magnetic nanoparticles. Magnetosomes have a variety of clinical and biotechnological applications. Magnetosomes are currently difficult to produce at large scale. We developed a simple, scalable, fermentation strategy for magnetosome production. The methods developed will aid development of magnetosome technologies.
The development of a simple pH-stat fed-batch fermentation strategy for the production of Magnetospirillum gryphiswaldense MSR-1 and magnetosomes (nanoscale magnetic organelles with biotechnological applications) is described. Flow cytometry was exploited as a powerful analytical tool for process development, enabling rapid monitoring of cell morphology, physiology and polyhydroxyalkanoate production. The pH-stat fed-batch growth strategy was developed by varying the concentrations of the carbon source (lactic acid) and the alternative electron acceptor (sodium nitrate) in the feed. Growth conditions were optimized on the basis of biomass concentration, cellular magnetism (indicative of magnetosome production), and intracellular iron concentration. The highest biomass concentration and cellular iron content achieved were an optical density at 565 nm of 15.5 (equivalent to 4.2 g DCW·L−1) and 33.1 mg iron·g−1 DCW, respectively. This study demonstrates the importance of analyzing bacterial physiology during fermentation development and will potentially aid the industrial production of magnetosomes, which can be used in a wide range of biotechnology and healthcare applications.
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Affiliation(s)
- Alfred Fernández-Castané
- School of Chemical Engineering, University of Birmingham, B15 2TT, Birmingham, UK; Institute of Microbiology & Infection, University of Birmingham, B15 2TT, Birmingham, UK.
| | - Hong Li
- School of Chemical Engineering, University of Birmingham, B15 2TT, Birmingham, UK.
| | - Owen R T Thomas
- School of Chemical Engineering, University of Birmingham, B15 2TT, Birmingham, UK.
| | - Tim W Overton
- School of Chemical Engineering, University of Birmingham, B15 2TT, Birmingham, UK; Institute of Microbiology & Infection, University of Birmingham, B15 2TT, Birmingham, UK.
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Fonseca A, Ishoey T, Espinoza C, Pérez-Pantoja D, Manghisi A, Morabito M, Salas-Burgos A, Gallardo VA. Genomic features of "Candidatus Venteria ishoeyi", a new sulfur-oxidizing macrobacterium from the Humboldt Sulfuretum off Chile. PLoS One 2017; 12:e0188371. [PMID: 29236755 PMCID: PMC5728499 DOI: 10.1371/journal.pone.0188371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
The Humboldt Sulfuretum (HS), in the productive Humboldt Eastern Boundary Current Upwelling Ecosystem, extends under the hypoxic waters of the Peru-Chile Undercurrent (ca. 6°S and ca. 36°S). Studies show that primeval sulfuretums held diverse prokaryotic life, and, while rare today, still sustain species-rich giant sulfur-oxidizing bacterial communities. We here present the genomic features of a new bacteria of the HS, "Candidatus Venteria ishoeyi" ("Ca. V. ishoeyi") in the family Thiotrichaceae.Three identical filaments were micro-manipulated from reduced sediments collected off central Chile; their DNA was extracted, amplified, and sequenced by a Roche 454 GS FLX platform. Using three sequenced libraries and through de novo genome assembly, a draft genome of 5.7 Mbp, 495 scaffolds, and a N50 of 70 kbp, was obtained. The 16S rRNA gene phylogenetic analysis showed that "Ca. V. ishoeyi" is related to non-vacuolate forms presently known as Beggiatoa or Beggiatoa-like forms. The complete set of genes involved in respiratory nitrate-reduction to dinitrogen was identified in "Ca. V. ishoeyi"; including genes likely leading to ammonification. As expected, the sulfur-oxidation pathway reported for other sulfur-oxidizing bacteria were deduced and also, key inorganic and organic carbon acquisition related genes were identified. Unexpectedly, the genome of "Ca. V. ishoeyi" contained numerous CRISPR repeats and an I-F CRISPR-Cas type system gene coding array. Findings further show that, as a member of an eons-old marine ecosystem, "Ca. V. ishoeyi" contains the needed metabolic plasticity for life in an increasingly oxygenated and variable ocean.
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Affiliation(s)
- Alexis Fonseca
- Department of Pharmacology, University of Concepcion, Concepcion, Chile
- Department of Oceanography, University of Concepcion, Concepcion, Chile
| | - Thomas Ishoey
- Independent consultant, Encinitas, California, United States of America
| | - Carola Espinoza
- Department of Oceanography, University of Concepcion, Concepcion, Chile
- College of Ocean Science and Resources, Institute Marine Affairs and Resource Management, National Taiwan Ocean University, Keelung, Taiwan
| | - Danilo Pérez-Pantoja
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, San Joaquin, Santiago, Chile
| | - Antonio Manghisi
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Marina Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | | | - Víctor A. Gallardo
- Department of Oceanography, University of Concepcion, Concepcion, Chile
- College of Ocean Science and Resources, Institute Marine Affairs and Resource Management, National Taiwan Ocean University, Keelung, Taiwan
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Mickoleit F, Schüler D. Generation of Multifunctional Magnetic Nanoparticles with Amplified Catalytic Activities by Genetic Expression of Enzyme Arrays on Bacterial Magnetosomes. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/adbi.201700109] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Frank Mickoleit
- Department Microbiology; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| | - Dirk Schüler
- Department Microbiology; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
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36
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Samad MS, Johns C, Richards KG, Lanigan GJ, de Klein CAM, Clough TJ, Morales SE. Response to nitrogen addition reveals metabolic and ecological strategies of soil bacteria. Mol Ecol 2017; 26:5500-5514. [DOI: 10.1111/mec.14275] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/22/2017] [Accepted: 07/24/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Md Sainur Samad
- Department of Microbiology and Immunology; Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Charlotte Johns
- Department of Soil and Physical Sciences; Lincoln University; Lincoln New Zealand
| | | | | | | | - Timothy J. Clough
- Department of Soil and Physical Sciences; Lincoln University; Lincoln New Zealand
| | - Sergio E. Morales
- Department of Microbiology and Immunology; Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
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Wang Q, Wang X, Zhang W, Li X, Zhou Y, Li D, Wang Y, Tian J, Jiang W, Zhang Z, Peng Y, Wang L, Li Y, Li J. Physiological characteristics of Magnetospirillum gryphiswaldense MSR-1 that control cell growth under high-iron and low-oxygen conditions. Sci Rep 2017; 7:2800. [PMID: 28584275 PMCID: PMC5459824 DOI: 10.1038/s41598-017-03012-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/21/2017] [Indexed: 11/17/2022] Open
Abstract
Magnetosome formation by Magnetospirillum gryphiswaldense MSR-1 is dependent on iron and oxygen levels. We used transcriptome to evaluate transcriptional profiles of magnetic and non-magnetic MSR-1 cells cultured under high-iron and low-iron conditions. A total of 80 differentially expressed genes (DEGs) were identified, including 53 upregulated and 27 downregulated under high-iron condition. These DEGs belonged to the functional categories of biological regulation, oxidation-reduction process, and ion binding and transport, and were involved in sulfur metabolism and cysteine/methionine metabolism. Comparison with our previous results from transcriptome data under oxygen-controlled conditions indicated that transcription of mam or mms was not regulated by oxygen or iron signals. 17 common DEGs in iron- and oxygen-transcriptomes were involved in energy production, iron transport, and iron metabolism. Some unknown-function DEGs participate in iron transport and metabolism, and some are potential biomarkers for identification of Magnetospirillum strains. IrrA and IrrB regulate iron transport in response to low-oxygen and high-iron signals, respectively. Six transcription factors were predicted to regulate DEGs. Fur and Crp particularly co-regulate DEGs in response to changes in iron or oxygen levels, in a proposed joint regulatory network of DEGs. Our findings provide new insights into biomineralization processes under high- vs. low-iron conditions in magnetotactic bacteria.
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Affiliation(s)
- Qing Wang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Xu Wang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Weijia Zhang
- Institute of Deep-sea Science and Engineering, China Academy of Sciences, Sanya, 572000, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Xianyu Li
- Beijing Key Laboratory of Traditional Chinese Medicine Basic Research on Prevention and Treatment for Major Diseases, Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, 100700, P.R. China
| | - Yuan Zhou
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Dan Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Yinjia Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P.R. China
| | - Jiesheng Tian
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Wei Jiang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
| | - Ziding Zhang
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Youliang Peng
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China
| | - Lei Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P.R. China
| | - Ying Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China. .,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China.
| | - Jilun Li
- State Key Laboratories for Agro-biotechnology, China Agricultural University, Beijing, 100193, P.R. China.,France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P.R. China
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Abstract
Magnetotactic bacteria derive their magnetic orientation from magnetosomes, which are unique organelles that contain nanometre-sized crystals of magnetic iron minerals. Although these organelles have evident potential for exciting biotechnological applications, a lack of genetically tractable magnetotactic bacteria had hampered the development of such tools; however, in the past decade, genetic studies using two model Magnetospirillum species have revealed much about the mechanisms of magnetosome biogenesis. In this Review, we highlight these new insights and place the molecular mechanisms of magnetosome biogenesis in the context of the complex cell biology of Magnetospirillum spp. Furthermore, we discuss the diverse properties of magnetosome biogenesis in other species of magnetotactic bacteria and consider the value of genetically 'magnetizing' non-magnetotactic bacteria. Finally, we discuss future prospects for this highly interdisciplinary and rapidly advancing field.
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Araujo ACV, Morillo V, Cypriano J, Teixeira LCRS, Leão P, Lyra S, Almeida LGD, Bazylinski DA, Ribeiro de Vasconcelos AT, Abreu F, Lins U. Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment. BMC Genomics 2016; 17:726. [PMID: 27801294 PMCID: PMC5088516 DOI: 10.1186/s12864-016-3064-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnetotactic bacteria (MTB) are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments. RESULTS Genomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccus Magnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3O4) magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 μm s-1. High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome of Mf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity. Mf. australis strain IT-1 and Magnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high. CONCLUSION Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively large number of genes encoding transporters as well as chemotaxis receptors in the genome of Mf. australis strain IT-1 combined with its rapid swimming velocities, indicate that cells respond rapidly to environmental changes.
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Affiliation(s)
- Ana Carolina Vieira Araujo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.,Current institution: Departamento de Biologia, Universidade Federal de São Carlos, 18052-780, Sorocaba, SP, Brazil
| | - Viviana Morillo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.,School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Jefferson Cypriano
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | | | - Pedro Leão
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Sidcley Lyra
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Luiz Gonzaga de Almeida
- Departamento de Matemática Aplicada e Computacional, Laboratório Nacional de Computação Científica, 25651-070, Petrópolis, RJ, Brazil
| | - Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Ana Tereza Ribeiro de Vasconcelos
- Departamento de Matemática Aplicada e Computacional, Laboratório Nacional de Computação Científica, 25651-070, Petrópolis, RJ, Brazil
| | - Fernanda Abreu
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Ulysses Lins
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
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Cho IK, Wang S, Mao H, Chan AWS. Genetic engineered molecular imaging probes for applications in cell therapy: emphasis on MRI approach. Am J Nucl Med Mol Imaging 2016; 6:234-261. [PMID: 27766183 PMCID: PMC5069277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 08/31/2016] [Indexed: 06/06/2023]
Abstract
Recent advances in stem cell-based regenerative medicine, cell replacement therapy, and genome editing technologies (i.e. CRISPR-Cas 9) have sparked great interest in in vivo cell monitoring. Molecular imaging promises a unique approach to noninvasively monitor cellular and molecular phenomena, including cell survival, migration, proliferation, and even differentiation at the whole organismal level. Several imaging modalities and strategies have been explored for monitoring cell grafts in vivo. We begin this review with an introduction describing the progress in stem cell technology, with a perspective toward cell replacement therapy. The importance of molecular imaging in reporting and assessing the status of cell grafts and their relation to the local microenvironment is highlighted since the current knowledge gap is one of the major obstacles in clinical translation of stem cell therapy. Based on currently available imaging techniques, we provide a brief discussion on the pros and cons of each imaging modality used for monitoring cell grafts with particular emphasis on magnetic resonance imaging (MRI) and the reporter gene approach. Finally, we conclude with a comprehensive discussion of future directions of applying molecular imaging in regenerative medicine to emphasize further the importance of correlating cell graft conditions and clinical outcomes to advance regenerative medicine.
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Affiliation(s)
- In K Cho
- Department of Human Genetics, Emory University School of MedicineAtlanta, GA, USA
- Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research CenterAtlanta, GA, USA
| | - Silun Wang
- Department of Radiology and Imaging Sciences, Emory University School of MedicineAtlanta, GA, USA
| | - Hui Mao
- Department of Radiology and Imaging Sciences, Emory University School of MedicineAtlanta, GA, USA
| | - Anthony WS Chan
- Department of Human Genetics, Emory University School of MedicineAtlanta, GA, USA
- Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research CenterAtlanta, GA, USA
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Wang X, Wang Q, Zhang Y, Wang Y, Zhou Y, Zhang W, Wen T, Li L, Zuo M, Zhang Z, Tian J, Jiang W, Li Y, Wang L, Li J. Transcriptome analysis reveals physiological characteristics required for magnetosome formation in Magnetospirillum gryphiswaldense MSR-1. Environ Microbiol Rep 2016; 8:371-381. [PMID: 27043321 DOI: 10.1111/1758-2229.12395] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 02/21/2016] [Indexed: 06/05/2023]
Abstract
Magnetosome synthesis ability of Magnetospirillum gryphiswaldense MSR-1 in an autofermentor can be precisely controlled through strict control of dissolved oxygen concentration. In this study, using transcriptome data we discovered gene transcriptional differences and compared physiological characteristics of MSR-1 cells cultured under aerobic (high-oxygen) and micro-aerobic (low-oxygen) conditions. The results showed that 77 genes were up-regulated and 95 genes were down-regulated significantly under micro-aerobic situation. These genes were involved primarily in the categories of cell metabolism, transport, regulation and unknown-function proteins. The nutrient transport and physiological metabolism were slowed down under micro-aerobic condition, whereas dissimilatory denitrification pathways were activated and it may supplemental energy was made available for magnetosome synthesis. The result suggested that the genes of magnetosome membrane proteins (Mam and Mms) are not directly regulated by oxygen level, or are constitutively expressed. A proposed regulatory network of differentially expressed genes reflects the complexity of physiological metabolism in MSR-1, and suggests that some yet-unknown functional proteins play important roles such as ferric iron uptake and transport during magnetosome synthesis. The transcriptome data provides a holistic view of the responses of MSR-1 cells to differing oxygen levels. This approach will give new insights into general principles of magnetosome formation.
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Affiliation(s)
- Xu Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Qing Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Yang Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Yinjia Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P. R. China
| | - Yuan Zhou
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
| | - Weijia Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Tong Wen
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Li Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Meiqing Zuo
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Ziding Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
| | - Jiesheng Tian
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Wei Jiang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Ying Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
| | - Lei Wang
- Tianjin Biochip Corporation, Tianjin, 300457, P. R. China
| | - Jilun Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P. R. China
- France-China Bio-mineralization and Nano-structure Laboratory, Beijing, 100193, P. R. China
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Lohße A, Kolinko I, Raschdorf O, Uebe R, Borg S, Brachmann A, Plitzko JM, Müller R, Zhang Y, Schüler D. Overproduction of Magnetosomes by Genomic Amplification of Biosynthesis-Related Gene Clusters in a Magnetotactic Bacterium. Appl Environ Microbiol 2016; 82:3032-41. [PMID: 26969709 DOI: 10.1128/AEM.03860-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/07/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Magnetotactic bacteria biosynthesize specific organelles, the magnetosomes, which are membrane-enclosed crystals of a magnetic iron mineral that are aligned in a linear chain. The number and size of magnetosome particles have to be critically controlled to build a sensor sufficiently strong to ensure the efficient alignment of cells within Earth's weak magnetic field while at the same time minimizing the metabolic costs imposed by excessive magnetosome biosynthesis. Apart from their biological function, bacterial magnetosomes have gained considerable interest since they provide a highly useful model for prokaryotic organelle formation and represent biogenic magnetic nanoparticles with exceptional properties. However, potential applications have been hampered by the difficult cultivation of these fastidious bacteria and their poor yields of magnetosomes. In this study, we found that the size and number of magnetosomes within the cell are controlled by many different Mam and Mms proteins. We present a strategy for the overexpression of magnetosome biosynthesis genes in the alphaproteobacterium Magnetospirillum gryphiswaldense by chromosomal multiplication of individual and multiple magnetosome gene clusters via transposition. While stepwise amplification of the mms6 operon resulted in the formation of increasingly larger crystals (increase of ∼35%), the duplication of all major magnetosome operons (mamGFDC, mamAB, mms6, and mamXY, comprising 29 genes in total) yielded an overproducing strain in which magnetosome numbers were 2.2-fold increased. We demonstrate that the tuned expression of the mam and mms clusters provides a powerful strategy for the control of magnetosome size and number, thereby setting the stage for high-yield production of tailored magnetic nanoparticles by synthetic biology approaches. IMPORTANCE Before our study, it had remained unknown how the upper sizes and numbers of magnetosomes are genetically regulated, and overproduction of magnetosome biosynthesis had not been achieved, owing to the difficulties of large-scale genome engineering in the recalcitrant magnetotactic bacteria. In this study, we established and systematically explored a strategy for the overexpression of magnetosome biosynthesis genes by genomic amplification of single and multiple magnetosome gene clusters via sequential chromosomal insertion by transposition. Our findings also indicate that the expression levels of magnetosome proteins together limit the upper size and number of magnetosomes within the cell. We demonstrate that tuned overexpression of magnetosome gene clusters provides a powerful strategy for the precise control of magnetosome size and number.
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Jones SR, Wilson TD, Brown ME, Rahn-Lee L, Yu Y, Fredriksen LL, Ozyamak E, Komeili A, Chang MC. Genetic and biochemical investigations of the role of MamP in redox control of iron biomineralization in Magnetospirillum magneticum. Proc Natl Acad Sci U S A 2015; 112:3904-9. [PMID: 25775527 DOI: 10.1073/pnas.1417614112] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Magnetotactic bacteria have evolved complex subcellular machinery to construct linear chains of magnetite nanocrystals that allow the host cell to sense direction. Each mixed-valent iron nanoparticle is mineralized from soluble iron within a membrane-encapsulated vesicle termed the magnetosome, which serves as a specialized compartment that regulates the iron, redox, and pH environment of the growing mineral. To dissect the biological components that control this process, we have carried out a genetic and biochemical study of proteins proposed to function in iron mineralization. In this study, we show that the redox sites of c-type cytochromes of the Magnetospirillum magneticum AMB-1 magnetosome island, MamP and MamT, are essential to their physiological function and that ablation of one or both heme motifs leads to loss of function, suggesting that their ability to carry out redox chemistry in vivo is important. We also develop a method to heterologously express fully heme-loaded MamP from AMB-1 for in vitro biochemical studies, which show that its Fe(III)-Fe(II) redox couple is set at an unusual potential (-89 ± 11 mV) compared with other related cytochromes involved in iron reduction or oxidation. Despite its low reduction potential, it remains competent to oxidize Fe(II) to Fe(III) and mineralize iron to produce mixed-valent iron oxides. Finally, in vitro mineralization experiments suggest that Mms mineral-templating peptides from AMB-1 can modulate the iron redox chemistry of MamP.
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Amor M, Busigny V, Durand-Dubief M, Tharaud M, Ona-Nguema G, Gélabert A, Alphandéry E, Menguy N, Benedetti MF, Chebbi I, Guyot F. Chemical signature of magnetotactic bacteria. Proc Natl Acad Sci U S A 2015; 112:1699-703. [PMID: 25624469 DOI: 10.1073/pnas.1414112112] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.
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45
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Rahn-Lee L, Byrne ME, Zhang M, Le Sage D, Glenn DR, Milbourne T, Walsworth RL, Vali H, Komeili A. A genetic strategy for probing the functional diversity of magnetosome formation. PLoS Genet 2015; 11:e1004811. [PMID: 25569806 PMCID: PMC4287615 DOI: 10.1371/journal.pgen.1004811] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Model genetic systems are invaluable, but limit us to understanding only a few organisms in detail, missing the variations in biological processes that are performed by related organisms. One such diverse process is the formation of magnetosome organelles by magnetotactic bacteria. Studies of model magnetotactic α-proteobacteria have demonstrated that magnetosomes are cubo-octahedral magnetite crystals that are synthesized within pre-existing membrane compartments derived from the inner membrane and orchestrated by a specific set of genes encoded within a genomic island. However, this model cannot explain all magnetosome formation, which is phenotypically and genetically diverse. For example, Desulfovibrio magneticus RS-1, a δ-proteobacterium for which we lack genetic tools, produces tooth-shaped magnetite crystals that may or may not be encased by a membrane with a magnetosome gene island that diverges significantly from those of the α-proteobacteria. To probe the functional diversity of magnetosome formation, we used modern sequencing technology to identify hits in RS-1 mutated with UV or chemical mutagens. We isolated and characterized mutant alleles of 10 magnetosome genes in RS-1, 7 of which are not found in the α-proteobacterial models. These findings have implications for our understanding of magnetosome formation in general and demonstrate the feasibility of applying a modern genetic approach to an organism for which classic genetic tools are not available.
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Affiliation(s)
- Lilah Rahn-Lee
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, United States of America
| | - Meghan E. Byrne
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, United States of America
| | - Manjing Zhang
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, United States of America
| | - David Le Sage
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, United States of America
| | - David R. Glenn
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, United States of America
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Timothy Milbourne
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ronald L. Walsworth
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, United States of America
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Hojatollah Vali
- Facility for Electron Microscopy Research, McGill University, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada
| | - Arash Komeili
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, United States of America
- * E-mail:
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Popp F, Armitage JP, Schüler D. Polarity of bacterial magnetotaxis is controlled by aerotaxis through a common sensory pathway. Nat Commun 2014; 5. [DOI: 10.1038/ncomms6398] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 09/26/2014] [Indexed: 02/04/2023] Open
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47
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Taoka A, Eguchi Y, Mise S, Oestreicher Z, Uno F, Fukumori Y. A magnetosome-associated cytochrome MamP is critical for magnetite crystal growth during the exponential growth phase. FEMS Microbiol Lett 2014; 358:21-9. [PMID: 25048532 DOI: 10.1111/1574-6968.12541] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 07/04/2014] [Accepted: 07/11/2014] [Indexed: 01/20/2023] Open
Abstract
Magnetotactic bacteria use a specific set of conserved proteins to biomineralize crystals of magnetite or greigite within their cells in organelles called magnetosomes. Using Magnetospirillum magneticum AMB-1, we examined one of the magnetotactic bacteria-specific conserved proteins named MamP that was recently reported as a new type of cytochrome c that has iron oxidase activity. We found that MamP is a membrane-bound cytochrome, and the MamP content increases during the exponential growth phase compared to two other magnetosome-associated proteins on the same operon, MamA and MamK. To assess the function of MamP, we overproduced MamP from plasmids in wild-type (WT) AMB-1 and found that during the exponential phase of growth, these cells contained more magnetite crystals that were the same size as crystals in WT cells. Conversely, when the heme c-binding motifs within the mamP on the plasmid was mutated, the cells produced the same number of crystals, but smaller crystals than in WT cells during exponential growth. These results strongly suggest that during the exponential phase of growth, MamP is crucial to the normal growth of magnetite crystals during biomineralization.
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Affiliation(s)
- Azuma Taoka
- School of Natural System, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Japan; Bio-AFM Frontier Research Center, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Japan
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Abstract
The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types--periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed.
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Li Y, Sabaty M, Borg S, Silva KT, Pignol D, Schüler D. The oxygen sensor MgFnr controls magnetite biomineralization by regulation of denitrification in Magnetospirillum gryphiswaldense. BMC Microbiol 2014; 14:153. [PMID: 24915802 PMCID: PMC4065386 DOI: 10.1186/1471-2180-14-153] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/28/2014] [Indexed: 11/10/2022] Open
Abstract
Background Magnetotactic bacteria are capable of synthesizing magnetosomes only under oxygen-limited conditions. However, the mechanism of the aerobic repression on magnetite biomineralization has remained unknown. In Escherichia coli and other bacteria, Fnr (fumarate and nitrate reduction regulator) proteins are known to be involved in controlling the switch between microaerobic and aerobic metabolism. Here, we report on an Fnr-like protein (MgFnr) and its role in growth metabolism and magnetite biomineralization in the alphaproteobacterium Magnetospirillum gryphiswaldense. Results Deletion of Mgfnr not only resulted in decreased N2 production due to reduced N2O reductase activity, but also impaired magnetite biomineralization under microaerobic conditions in the presence of nitrate. Overexpression of MgFnr in the WT also caused the synthesis of smaller magnetite particles under anaerobic and microaerobic conditions in the presence of nitrate. These data suggest that proper expression of MgFnr is required for WT-like magnetosome synthesis, which is regulated by oxygen. Analyses of transcriptional gusA reporter fusions revealed that besides showing similar properties to Fnr proteins reported in other bacteria, MgFnr is involved in the repression of the expression of denitrification genes nor and nosZ under aerobic conditions, possibly owing to several unique amino acid residues specific to MTB-Fnr. Conclusions We have identified and thoroughly characterized the first regulatory protein mediating denitrification growth and magnetite biomineralization in response to different oxygen conditions in a magnetotactic bacterium. Our findings reveal that the global oxygen regulator MgFnr is a genuine O2 sensor. It is involved in controlling expression of denitrification genes and thereby plays an indirect role in maintaining proper redox conditions required for magnetite biomineralization.
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Affiliation(s)
| | | | | | | | | | - Dirk Schüler
- Lehrstuhl f, Mikrobiologie, Universität Bayreuth, 95447 Bayreuth, Germany.
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Li Y, Raschdorf O, Silva KT, Schüler D. The terminal oxidase cbb3 functions in redox control of magnetite biomineralization in Magnetospirillum gryphiswaldense. J Bacteriol 2014; 196:2552-62. [PMID: 24794567 DOI: 10.1128/JB.01652-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The biomineralization of magnetosomes in Magnetospirillum gryphiswaldense and other magnetotactic bacteria occurs only under suboxic conditions. However, the mechanism of oxygen regulation and redox control of biosynthesis of the mixed-valence iron oxide magnetite [FeII(FeIII)2O4] is still unclear. Here, we set out to investigate the role of aerobic respiration in both energy metabolism and magnetite biomineralization of M. gryphiswaldense. Although three operons encoding putative terminal cbb3-type, aa3-type, and bd-type oxidases were identified in the genome assembly of M. gryphiswaldense, genetic and biochemical analyses revealed that only cbb3 and bd are required for oxygen respiration, whereas aa3 had no physiological significance under the tested conditions. While the loss of bd had no effects on growth and magnetosome synthesis, inactivation of cbb3 caused pleiotropic effects under microaerobic conditions in the presence of nitrate. In addition to their incapability of simultaneous nitrate and oxygen reduction, cbb3-deficient cells had complex magnetosome phenotypes and aberrant morphologies, probably by disturbing the redox balance required for proper growth and magnetite biomineralization. Altogether, besides being the primary terminal oxidase for aerobic respiration, cbb3 oxidase may serve as an oxygen sensor and have a further role in poising proper redox conditions required for magnetite biomineralization.
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