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Dirk Schüler - One of the best experts on this subject based on the ideXlab platform.
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Spatio-temporal organization of chemotaxis pathways in Magnetospirillum gryphiswaldense.
Applied and environmental microbiology, 2020Co-Authors: Daniel Pfeiffer, Julian Herz, Julia Schmiedel, Felix Popp, Dirk SchülerAbstract:Magnetospirillum gryphiswaldense employs iron-rich nanoparticles for magnetic navigation within environmental redox gradients. This behavior termed magneto-aerotaxis was previously shown to rely on the sensory pathway CheOp1, but the precise localization of CheOp1-related chemoreceptor arrays during the cell-cycle, and its possible interconnection with three other chemotaxis pathways has remained unstudied. Here, we analyzed the localization of chemoreceptor-associated adaptor protein CheW1 and histidine kinase CheA1 by super-resolution microscopy in a spatio-temporal manner. CheW1 localized in dynamic clusters that undergo occasional segregation and fusion events at lateral sites of both cell poles. Newly formed smaller clusters originating at midcell before completion of cytokinesis were found to grow in size during the cell-cycle. Bipolar CheA1 localization and formation of aerotactic swim halos were affected depending on the fluorescent protein tag, indicating that CheA1 localization is important for aerotaxis. Furthermore, polar CheW1 localization was independent of cheOp2-4, but lost in absence of cheOp1 or cheA1. Results were corroborated by the detection of a direct protein interaction between CheA1 and CheW1, and by the observation that cheOp2- and cheOp3-encoded CheW-paralogs localized in spatially distinct smaller clusters at the cell boundary. Although the findings of a minor aerotaxis-related CheOp4 phenotype and weak protein interactions between CheOp1 and CheOp4 by two-hybrid analysis implied that CheW1 and CheW4 might be part of the same chemoreceptor array, CheW4 was localized in spatially distinct polar-lateral arrays independent of CheOp1, suggesting that CheOp1 and CheOp4 are also not connected at the molecular level. Importance Magnetotactic bacteria (MTB) use the geomagnetic field for navigation in aquatic redox gradients. However, the highly complex signal transduction networks in these environmental microbes are only poorly understood. Here, we analyzed the localization of selected chemotaxis proteins to spatially and temporarily resolve chemotaxis array localization in Magnetospirillum gryphiswaldense. Our findings suggest that bipolar localization of chemotaxis arrays related to the key signaling pathway CheOp1 is important for aerotaxis, and that CheOp1 signaling units assemble independent of the three other chemotaxis pathways present in M. gryphiswaldense. Overall, our results provide deeper insights into the complex organization of signaling pathways in MTB and add to the general understanding of environmental bacteria possessing multiple chemotaxis pathways.
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spatiotemporal organization of chemotaxis pathways in Magnetospirillum gryphiswaldense
Applied and Environmental Microbiology, 2020Co-Authors: Daniel Pfeiffer, Julian Herz, Julia Schmiedel, Felix Popp, Dirk SchülerAbstract:Magnetospirillum gryphiswaldense employs iron-rich nanoparticles for magnetic navigation within environmental redox gradients. This behavior termed magneto-aerotaxis was previously shown to rely on the sensory pathway CheOp1, but the precise localization of CheOp1-related chemoreceptor arrays during the cell cycle and its possible interconnection with three other chemotaxis pathways have remained unstudied. Here, we analyzed the localization of chemoreceptor-associated adaptor protein CheW1 and histidine kinase CheA1 by superresolution microscopy in a spatiotemporal manner. CheW1 localized in dynamic clusters that undergo occasional segregation and fusion events at lateral sites of both cell poles. Newly formed smaller clusters originating at midcell before completion of cytokinesis were found to grow in size during the cell cycle. Bipolar CheA1 localization and formation of aerotactic swim halos were affected depending on the fluorescent protein tag, indicating that CheA1 localization is important for aerotaxis. Furthermore, polar CheW1 localization was independent of cheOp2 to cheOp4 but lost in the absence of cheOp1 or cheA1 Results were corroborated by the detection of a direct protein interaction between CheA1 and CheW1 and by the observation that cheOp2- and cheOp3-encoded CheW paralogs localized in spatially distinct smaller clusters at the cell boundary. Although the findings of a minor aerotaxis-related CheOp4 phenotype and weak protein interactions between CheOp1 and CheOp4 by two-hybrid analysis implied that CheW1 and CheW4 might be part of the same chemoreceptor array, CheW4 was localized in spatially distinct polar-lateral arrays independent of CheOp1, suggesting that CheOp1 and CheOp4 are also not connected at the molecular level.IMPORTANCE Magnetotactic bacteria (MTB) use the geomagnetic field for navigation in aquatic redox gradients. However, the highly complex signal transduction networks in these environmental microbes are poorly understood. Here, we analyzed the localization of selected chemotaxis proteins to spatially and temporally resolve chemotaxis array localization in Magnetospirillum gryphiswaldense Our findings suggest that bipolar localization of chemotaxis arrays related to the key signaling pathway CheOp1 is important for aerotaxis and that CheOp1 signaling units assemble independent of the three other chemotaxis pathways present in M. gryphiswaldense Overall, our results provide deeper insights into the complex organization of signaling pathways in MTB and add to the general understanding of environmental bacteria possessing multiple chemotaxis pathways.
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An automated oxystat fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense
Microbial cell factories, 2020Co-Authors: Cornelius N. Riese, René Uebe, Sabine Rosenfeldt, Anna S. Schenk, Valérie Jérôme, Ruth Freitag, Dirk SchülerAbstract: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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Single-step transfer of biosynthetic operons endows a non-magnetotactic Magnetospirillum strain from wetland with magnetosome biosynthesis.
Environmental microbiology, 2020Co-Authors: Marina V. Dziuba, René Uebe, Theresa Zwiener, Dirk SchülerAbstract: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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Mit modernen Methoden zu magnetischen Mikroben
BIOspektrum, 2019Co-Authors: Rudolf Amann, Dirk SchülerAbstract:Magnets, methods, and microbes have contributed to the study of magnetotactic bacteria over the past decades. On the way from an unlikely discovery to making Magnetospirillum the “Microbe of 2019” there has been a fruitful interaction of classical microbiological methods with emerging molecular techniques. This has turned the view of magnetotactic bacteria from microbial curiosities towards established models for prokaryotic cell biology and biomineralization.
Tadashi Matsunaga - One of the best experts on this subject based on the ideXlab platform.
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Cytoplasmic ATPase involved in ferrous ion uptake from magnetotactic bacterium Magnetospirillum magneticum AMB-1.
FEBS letters, 2007Co-Authors: Takeyuki Suzuki, Yoshiko Okamura, Haruko Takeyama, Atsushi Arakaki, Tadashi MatsunagaAbstract:A non-magnetic mutant of Magnetospirillum magneticum AMB-1 (NMA61), harboring a defective gene located in ORF4 (gene ID: amb4111) was generated by transposon mutagenesis. Biochemical characterization of the gene product of ORF4 revealed that it was localized in the cytoplasm and displayed ATPase activity. The ability of NMA61 to take up iron was severely compromised. Ferrous ion concentration in the medium decreased more with the wild-type than with NMA61, while the iron content in the cytoplasmic fraction of NMA61 was much lower than the wild-type strain. This cytoplasmic ATPase is essential for iron trafficking within M. magneticum AMB-1.
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Global Gene Expression Analysis of Iron-Inducible Genes in Magnetospirillum magneticum AMB-1
Journal of bacteriology, 2006Co-Authors: Takeyuki Suzuki, Yoshiko Okamura, Ronie J. Calugay, Haruko Takeyama, Tadashi MatsunagaAbstract:Iron uptake systems were identified by global expression profiling of Magnetospirillum magneticum AMB-1. feo, tpd, and ftr, which encode ferrous iron transporters, were up-regulated under iron-rich conditions. The concomitant rapid iron uptake and magnetite formation suggest that these uptake systems serve as iron supply lines for magnetosome synthesis.
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Catechol siderophore excretion by magnetotactic bacterium Magnetospirillum magneticum AMB-1.
Journal of bioscience and bioengineering, 2006Co-Authors: Ronie J. Calugay, Takeyuki Suzuki, Haruko Takeyama, Daikichi Mukoyama, Yorikane Fukuda, Kaneo Kanoh, Tadashi MatsunagaAbstract:Siderophore activity was detected in the culture supernatant of the magnetotactic bacterium Magnetospirillum magneticum AMB-1. Here we report the first structural elucidation of a siderophore produced by a magnetotactic bacterium. The structure of the purified compound was 3,4-dihydroxybenzoic acid as determined by nuclear magnetic resonance (NMR) and electro-spray ionization mass spectroscopy (ESI-MS).
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Complete Genome Sequence of the Facultative Anaerobic Magnetotactic Bacterium Magnetospirillum sp. strain AMB-1
DNA research : an international journal for rapid publication of reports on genes and genomes, 2005Co-Authors: Tadashi Matsunaga, Yoshiko Okamura, Aris Tri Wahyudi, Yorikane Fukuda, Yaeko Murase, Haruko TakeyamaAbstract:Magnetospirillum sp. strain AMB-1 is a Gram-negative a-proteobacterium that synthesizes nano-sized magnetites, referred to as magnetosomes, aligned intracellularly in a chain. The potential of this nano-sized material is growing and will be applicable to broad research areas. It has been expected that genome analysis would elucidate the mechanism of magnetosome formation by magnetic bacteria. Here we describe the genome of Magnetospirillum sp. AMB-1 wild type, which consists of a single circular chromosome of 4 967 148 bp. For identification of genes required for magnetosome formation, transposon mutagenesis and determination of magnetosome membrane proteins were performed. Analysis of a non-magnetic transposon mutant library focused on three unknown genes from 2752 unknown genes and three genes from 205 signal transduction genes. Partial proteome analysis of the magnetosome membrane revealed that the membrane contains numerous oxidation/reduction proteins and a signal response regulator that may function in magnetotaxis. Thus, oxidation/reduction proteins and elaborate multidomain signaling proteins were analyzed. This comprehensive genome analysis will enable resolution of the mechanisms of magnetosome formation and provide a template to determine how magnetic bacteria maintain a species-specific, nanosized, magnetic single domain and paramagnetic morphology.
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design and application of a new cryptic plasmid based shuttle vector for Magnetospirillum magneticum
Applied and Environmental Microbiology, 2003Co-Authors: Yoshiko Okamura, Shinji Kamiya, Toshifumi Sakaguchi, Haruko Takeyama, Takumi Sekine, Aris Tri Wahyudi, Rika Sato, Tadashi MatsunagaAbstract:A 3.7-kb cryptic plasmid designated pMGT was found in Magnetospirillum magneticum MGT-1. It was characterized and used for the development of an improved expression system in strain AMB-1 through the construction of a shuttle vector, pUMG. An electroporation method for magnetic bacteria that uses the cryptic plasmid was also developed.
Yongxin Pan - One of the best experts on this subject based on the ideXlab platform.
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Additional file 1: of Genomic evidence of the illumination response mechanism and evolutionary history of magnetotactic bacteria within the Rhodospirillaceae family
2019Co-Authors: Yinzhao Wang, Wei Lin, Giorgio Casaburi, Fengping Wang, Yongxin PanAbstract:Figure S1. Circular diagrams of the Magnetospirillum sp. XM-1 chromosome and plasmid show the relevant genome features. Figure S2. Colinearity plot shows the comparison of genome from the Magnetospirillum sp. XM-1 and Magnetospirillum magneticum AMB-1. Figure S3. (A) The comparison of iron related genes. (B) Summary of iron homeostasis features identified in the genomes. (C) Sketch of iron homeostasis systems in the Rhodospirillaceae family. Figure S4. The comparison of DNA damages repair genes. Figure S5. The comparison of the percentage of DNA damage repair gene from MTB and non-MTB. Figure S6. (A) Vann diagram of core, dispensable and specific genes from five groups. (B) Vann diagram of core, dispensable and specific genes. Figure S7. MTB strain XM-1 swam towards the UVA radiation and accumulated at the illuminate side of the quartz bottle. Figure S8. Sketch map shows the strategy of possible photosynthesis magnetotactic bacteria in Archean Eon when surface UV radiation was high. Magnetotaxis could help them to swim down to the ultraviolet tolerance photosynthesis zone (UTPZ) to avoid lethal doses of irradiation while harvest enough light. (PDF 3745 kb
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Complete Genome Sequence of Magnetospirillum sp. Strain XM-1, Isolated from the Xi’an City Moat, China
Genome announcements, 2016Co-Authors: Yinzhao Wang, Wei Lin, Tongwei Zhang, Bingfang Zhang, Yao Cai, Caiyun Yang, Yongxin PanAbstract:ABSTRACT The magnetotactic bacterium Magnetospirillum sp. strain XM-1 was recently isolated from the Xi9an City moat, China. It belongs to the Rhodospirillaceae family in the Alphaproteobacteria class. Here, we report the complete genome sequence of XM-1. The genome contains a single circular chromosome of 4,825,187 bp and a plasmid of 167,290 bp.
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Characterizing and optimizing magnetosome production of Magnetospirillum sp. XM-1 isolated from Xi'an City Moat, China.
FEMS microbiology letters, 2015Co-Authors: Yinzhao Wang, Wei Lin, Tongwei Zhang, Jiesheng Tian, Yvan Vander Heyden, Yongxin PanAbstract:Pure culture of magnetotactic bacteria is desirable to understand their physiology, evolution and biomineralization. Here, we report a new strain Magnetospirillum sp. XM-1 that was recently isolated and cultivated from the eutrophic city moat of Xi'an, China. Magnetosome biomineralization, crystallographic and magnetic properties of XM-1 were characterized by using a combination of transmission electron microscopy and rock magnetic methods. Cell growth and magnetite production was optimized by response surface methodology. We found that the Magnetospirillum strain XM-1 is different from the model strain Magnetospirillum magneticum AMB-1 in terms of magnetite magnetosomes, optimal growth temperature and nutrient requirements. Sodium succinate, sodium nitrate and ferric citrate are the three most significant factors associated with the optimization of cell growth and magnetosome production for XM-1.
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MamX encoded by the mamXY operon is involved in control of magnetosome maturation in Magnetospirillum gryphiswaldense MSR-1.
BMC microbiology, 2013Co-Authors: Jing Yang, Xiuliang Huang, Yongxin PanAbstract:Background Magnetotactic bacteria produce membrane-enveloped magnetite crystals (magnetosomes) whose formation is controlled primarily by a gene island termed the magnetosome island (MAI). Characterization of single gene and operon function in MAI has elucidated in part the genetic basis of magnetosome formation. The mamX gene, located in the mamXY operon, is highly conserved in the MAI of all Magnetospirillum strains studied to date. Little is known regarding the function of mamX in the process of biomineralization.
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Environmental Factors Affect Magnetite Magnetosome Synthesis in Magnetospirillum magneticum AMB-1: Implications for Biologically Controlled Mineralization
Geomicrobiology Journal, 2012Co-Authors: Yongxin PanAbstract:It is widely believed that magnetotactic bacteria (MTB) form membrane-enveloped magnetite crystals (magnetosomes) under strict genetic control. In this study, the Magnetospirillum magneticum strain...
Edmund Bäuerlein - One of the best experts on this subject based on the ideXlab platform.
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Research letterA simple light scattering method to assay magnetism in Magnetospirillum gryphiswaldense
FEMS Microbiology Letters, 1995Co-Authors: Dirk Schüler, Rainer Uhl, Edmund BäuerleinAbstract:A simple optical method was developed for assaying cellular magnetism in culture samples of magnetic spirilla. Cells are aligned parallel to the field lines in a magnetic field, resulting in a change in light scattering. The ratio of scattering intensities at different angles of magnetic field relative to the light beam (Cmag) is used to characterize the average magnetic orientation of the cells. Cmag was found to be well correlated with the average number of particles in different magnetic cell populations. Thus, estimations of magnetosome content can be made using magnetically induced differential light scattering. The method provides a fast and sensitive tool for monitoring the magnetite formation in growing cultures of Magnetospirillum gryphiswaldense.
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A simple light scattering method to assay magnetism in Magnetospirillum gryphiswaldense
FEMS Microbiology Letters, 1995Co-Authors: Dirk Schüler, Rainer Uhl, Edmund BäuerleinAbstract:Abstract A simple optical method was developed for assaying cellular magnetism in culture samples of magnetic spirilla. Cells are aligned parallel to the field lines in a magnetic field, resulting in a change in light scattering. The ratio of scattering intensities at different angles of magnetic field relative to the light beam (Cmag) is used to characterize the average magnetic orientation of the cells. Cmag was found to be well correlated with the average number of particles in different magnetic cell populations. Thus, estimations of magnetosome content can be made using magnetically induced differential light scattering. The method provides a fast and sensitive tool for monitoring the magnetite formation in growing cultures of Magnetospirillum gryphiswaldense.
Marina V. Dziuba - One of the best experts on this subject based on the ideXlab platform.
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Single-step transfer of biosynthetic operons endows a non-magnetotactic Magnetospirillum strain from wetland with magnetosome biosynthesis.
Environmental microbiology, 2020Co-Authors: Marina V. Dziuba, René Uebe, Theresa Zwiener, Dirk SchülerAbstract: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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Draft Genome Sequences of Two Magnetotactic Bacteria, Magnetospirillum moscoviense BB-1 and Magnetospirillum marisnigri SP-1.
Genome announcements, 2016Co-Authors: Veronika V. Koziaeva, Marina V. Dziuba, Timophey M. Ivanov, Boris B. Kuznetsov, Konstantin G. Skryabin, Denis S. GrouzdevAbstract:ABSTRACT We report here the draft genome sequences of two recently isolated magnetotactic species, Magnetospirillum moscoviense BB-1 and Magnetospirillum marisnigri SP-1. The genome of M. moscoviense BB-1 has 4,164,497 bp, 65.2% G+C content, and comprises 207 contigs. The genome of M. marisnigri SP-1 consists of 131 contigs and has a length of 4,619,819 bp and 64.7% G+C content.
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Magnetospirillum caucaseum sp. nov., Magnetospirillum marisnigri sp. nov. and Magnetospirillum moscoviense sp. nov., freshwater magnetotactic bacteria isolated from three distinct geographical locations in European Russia.
International journal of systematic and evolutionary microbiology, 2016Co-Authors: Marina V. Dziuba, Veronika V. Koziaeva, Denis S. Grouzdev, Ekaterina I Burganskaya, R. V. Baslerov, Tatjana V. Kolganova, Alexander Chernyadyev, Georgy A. Osipov, E. L. Andrianova, Vladimir M. GorlenkoAbstract:Three strains of helical, magnetotactic bacteria, SO-1T, SP-1T and BB-1T, were isolated from freshwater sediments collected from three distinct locations in European Russia. Phylogenetic analysis showed that the strains belong to the genus Magnetospirillum. Strains SO-1T and SP-1T showed the highest 16S rRNA gene sequence similarity to Magnetospirillum magnetotacticum MS-1T (99.3 and 98.1 %, respectively), and strain BB-1T with Magnetospirillum gryphiswaldense MSR-1T (97.3 %). The tree based on concatenated deduced amino acid sequences of the MamA, B, K, M, O, P, Q and T proteins, which are involved in magnetosome formation, was congruent with the tree based on 16S rRNA gene sequences. The genomic DNA G+C contents of strains SO-1T, SP-1T and BB-1T were 65.9, 63.0 and 65.2 mol%, respectively. As major fatty acids, C18 : 1ω9, C16 : 1ω7c, C16 : 0 and C18 : 0 were detected. DNA–DNA hybridization values between the novel strains and their closest relatives in the genus Magnetospirillum were less than 51.7 ± 2.3 %. In contrast to M. magnetotacticum MS-1T, the strains could utilize butyrate and propionate; strains SO-1T and BB-1T could also utilize glycerol. Strain SP-1T showed strictly microaerophilic growth, whereas strains SO-1T and BB-1T were more tolerant of oxygen. The results of DNA–DNA hybridization and physiological tests allowed genotypic and phenotypic differentiation of the strains from each other as well as from the two species of Magnetospirillum with validly published names. Therefore, the strains represent novel species, for which we propose the names Magnetospirillum caucaseum sp. nov. (type strain SO-1T = DSM 28995T = VKM B-2936T), Magnetospirillum marisnigri sp. nov. (type strain SP-1T = DSM 29006T = VKM B-2938T) and Magnetospirillum moscoviense sp. nov. (type strain BB-1T = DSM 29455T = VKM B-2939T).
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Draft Genome Sequence of Magnetospirillum sp. Strain SO-1, a Freshwater Magnetotactic Bacterium Isolated from the Ol’khovka River, Russia
Genome announcements, 2014Co-Authors: Denis S. Grouzdev, Marina V. Dziuba, Boris B. Kuznetsov, Marina S. Sukhacheva, Andrey V. Mardanov, Aleksey V. Beletskiy, Konstantin G. SkryabinAbstract:ABSTRACT Here, we present the draft genome sequence of Magnetospirillum sp. strain SO-1, a freshwater magnetotactic spirillum isolated from the sediments of the Ol9khovka River, Russia.