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Magnetotactic bacteria

About: Magnetotactic bacteria is a research topic. Over the lifetime, 1118 publications have been published within this topic receiving 43741 citations.


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Journal ArticleDOI
TL;DR: It is observed that the amount and purity of TEX isolated magnetically with MNWs was higher than with NRs and MGs, and they were close to the results obtained using conventional non-magnetic isolation methods.
Abstract: Isolating and analyzing tumor-derived exosomes (TEX) can provide important information about the state of a tumor, facilitating early diagnosis and prognosis. Since current isolation methods are mostly laborious and expensive, we propose herein a fast and cost-effective method based on a magnetic nanoplatform to isolate TEX. In this work, we have tested our method using three magnetic nanostructures: (i) Ni magnetic nanowires (MNWs) (1500 × 40 nm), (ii) Fe3O4 nanorods (NRs) (41 × 7 nm), and (iii) Fe3O4 cube-octahedral magnetosomes (MGs) (45 nm) obtained from magnetotactic bacteria. The magnetic response of these nanostructures has been characterized, and we have followed their internalization inside canine osteosarcoma OSCA-8 cells. An overall depiction has been obtained using a combination of Fluorescence and Scanning Electron Microscopies. In addition, Transmission Electron Microscopy images have shown that the nanostructures, with different signs of degradation, ended up being incorporated in endosomal compartments inside the cells. Small intra-endosomal vesicles that could be precursors for TEX have also been identified. Finally, TEX have been isolated using our magnetic isolation method and analyzed with a Nanoparticle tracking analyzer (NanoSight). We observed that the amount and purity of TEX isolated magnetically with MNWs was higher than with NRs and MGs, and they were close to the results obtained using conventional non-magnetic isolation methods.

148 citations

Journal ArticleDOI
TL;DR: A novel type of dissimilatory sulfate-reducing bacterium, designated strain RS-1T, capable of producing intracellular magnetite particles (magnetosomes) was isolated from freshwater sulfide-rich sediments, and Phylogenetic analysis based on 16S rDNA sequences revealed that it is a member of the genus Desulfovibrio.
Abstract: A novel type of dissimilatory sulfate-reducing bacterium, designated strain RS-1T, capable of producing intracellular magnetite particles (magnetosomes) was isolated from freshwater sulfide-rich sediments. Phylogenetic analysis based on 16S rDNA sequences revealed that RS-1T is a member of the genus Desulfovibrio. Its closest known relative is Desulfovibrio burkinensis (sequence similarity of 98.7%). Strain RS-1T contains desulfoviridin, c-type cytochromes and, unlike other Desulfovibrio spp., it possesses menaquinone MK-7(H2) instead of MK-6 or MK-6(H2). Strain RS-1T is also unique compared with other members of Desulfovibrio in its ability to synthesize intracellular magnetite particles. A novel species, Desulfovibrio magneticus sp. nov., is proposed for RS-1T (= ATCC 700980T = DSM 13731T), a sulfate-reducing magnetotactic bacterium.

148 citations

Journal ArticleDOI
04 Jan 2002-Science
TL;DR: Shewanella putrefaciens CN32, a Gram-negative, facultative anaerobic bacterium that is capable of dissimilatory iron reduction, produced microscopic intracellular grains of iron oxide minerals during growth on two-line ferrihydrite in a hydrogen-argon atmosphere, suggesting an unexplored pathway for the cycling of iron by bacteria.
Abstract: Among prokaryotes, there are few examples of controlled mineral formation; the formation of crystalline iron oxides and sulfides [magnetite (Fe3O4) or greigite (Fe3S4)] by magnetotactic bacteria is an exception. Shewanella putrefaciens CN32, a Gram-negative, facultative anaerobic bacterium that is capable of dissimilatory iron reduction, produced microscopic intracellular grains of iron oxide minerals during growth on two-line ferrihydrite in a hydrogen-argon atmosphere. The minerals, formed at iron concentrations found in the soil and sedimentary environments where these bacteria are active, could represent an unexplored pathway for the cycling of iron by bacteria.

148 citations

Journal Article
TL;DR: This paper will outline aspects of the physiology and molecular biology of magnetosome formation, and the biotechnological potential of the biomineralization process is discussed.
Abstract: The ability of magnetotactic bacteria to orient and migrate along geomagnetic field lines is based on intracellular magnetic structures, the magnetosomes, which comprise nano-sized, membrane bound crystals of magnetic iron minerals. The formation of magnetosomes is achieved by a biological mechanism that controls the accumulation of iron and the biomineralization of magnetic crystals with a characteristic size and morphology within membrane vesicles. This paper focuses on the current knowledge about magnetotactic bacteria and will outline aspects of the physiology and molecular biology of magnetosome formation. The biotechnological potential of the biomineralization process is discussed.

148 citations

Journal ArticleDOI
TL;DR: In this article, a simple optical method was developed for assaying cellular magnetism in culture samples of magnetic spirilla, where cells are aligned parallel to the field lines in a magnetic field, resulting in a change in light scattering.
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.

146 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202339
202288
202137
202061
201950
201873