Topic
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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TL;DR: The results show that A. ferrooxidans have weak magnetotaxis and can be isolated by magnetophoresis, and the research of magnetotactic bacteria and bioleaching will get more benefit from it.
Abstract: There are similarities between magnetotactic bacteria and Acidithiobacillus ferrooxidans (A. ferrooxidans) which isolated from Acid mine drainage(AMD). The weak magnetotaxis of some bioleaching bacteria isolated were found by microscope. A magnetophoresis apparatus was designed based on these weak magnetotaxis and be used to analysis the movement of these strains. The physiological properties of the anear magnetic field strain and removed magnetic field strain which isolated successfully by magnetophoresis apparatus have large difference. The nanometer magnetic particles was extract from the Acidithiobacillus ferrooxidans which purified by spread plate method from AMFS and its main elements are Fe and O by energy spectrum analysis. The results show that A. ferrooxidans have weak magnetotaxis and can be isolated by magnetophoresis. With the development of this new isolating method, the research of magnetotactic bacteria and bioleaching will get more benefit from it.
2 citations
01 Jan 2002
TL;DR: In this paper, a magnetic harvest technique was used to focus magnetotactic cells on the sides of a harvest vessel and then forced them to swim parallel to the sides, to the top where they were collected.
Abstract: In this study, a variety of new techniques were developed to facilitate the study of magnetotactic responses, the collection of magnetotactic bacteria from environmental samples and to prepare them for analytical transmission electron microscopy (ATEM). A magnetic harvest technique developed here, employed changing the orientation of a weak magnetic field to focus magnetotactic cells on the sides of a harvest vessel and then forced them to swim parallel to the sides, to the top where they were collected. This technique minimised their contact with suspended sediment particles and the sides of the harvest vessel and yielded 109-1010 magnetotactic cells, with up to 20 morphologically distinct strains of magnetotactic bacteria, from relatively large quantities of suspended sediment (5.0 1) in a four-phase process. 3-aminopropyl triethoxy silane (APTES)-primed ultraviolet-B (UV-B)-irradiated PioloformTM (P*A) was more adhesive to cells than the most commonly used support films primed with carbon and poly-L-lysine. UV-B-irradiation of dehydrated cells adhered to P*A in the presence of air, induced a remarkable degree of stability, when exposed to a condensed electron beam, which facilitated the acquisition of phase-contrast lattice images with d values of 1.1 and 1.2 A, which was less than half the width of the smallest fringes reported previously in similar specimens. Using magnetosomal morphology, cellular ultrastructure and the habitat from which the cells came, 80 potentially different strains of magnetotactic bacteria were identified in the Moreton Bay region of Australia. There were 41 marine, 5 brackish and 34 freshwater strains differentiated. Nine types of magnetosome were analysed, with four types having idealised morphologies that have not been reported previously, including: irregularly truncated octahedral magnetite elongated in the [ 2 1 1 ] direction, with D-shaped projections; arrowhead-shaped magnetite with a single { 1 0 0} face on the wide end, with pick-shaped projections; arrowhead-shaped magnetite elongated bidirectionally, with centrosymmetric projections; and cubic magnetite elongated in the [ 1 10] direction, with tooth-shaped projections. A variety of magnetite magnetosomes with anomalous morphologies and structures were analysed here. Many of these structures resembled the magnetite particles in the Martian meteorite ALH84001 (McKay et al. 1996a). These anomalous nanophase magnetite particles had previously been reported as evidence of crystallisation from a super-heated fluid or vapour-phase growth by Bradley et al. (1996). Magnetite magnetosomes with axial ratios of 6:1, screw dislocations, irregular and spinel-law twinning, higher order { 2 1 1 } and { 5 1 1} faces, jagged and undulated faces, as well as lattice disorder and oxygen deficiencies in magnetite magnetosomes are also reported here. Observations were made of: the coprecipitation of a Ca-O-rich precipitate, possibly calcium carbonate (CaCO₃), with a variety of magnetite magnetosomes; the coprecipitation of a Si-0-rich precipitate, possibly amorphous silica (SiO₂), with magnetite magnetosomes; and the accumulation of Ti, Zn, Mg, Ca and Al in phosphorous- rich inclusions, collectively account for the concurrence and arrangement of nanophase magnetite, metal-carbonates and silica in ALH84001. One small magnetotactic spirillum produced magnetite magnetosomes with the same zone axis projections as does the hexaoctahedral magnetite in ALH84001. Collectively, this provide strong evidence supporting the claims that ALH84001 contains magnetofossils within biogenic carbonate concretions. Some immature bullet-shaped and tooth-shaped magnetosomes, were possibly composed of an unidentified phase, as well as magnetite. The unidentified phase was an iron oxide or hydroxide. It was hypothesised to be the precursor in the biomineralization of magnetite and was called here pre-magnetite. Low magnification and high resolution images of unstained dehydrated magnetotactic cells adhered to a variety of support films, with and without UV-B-irradiation, contained evidence of a magnetosomal matrix. Stained ultrasections of resin-embedded cells also contained evidence of the matrix. The matrix was 20-70 nm thick and surrounded bullet-shaped, cubooctahedral, D-shaped, irregular arrowhead-shaped and pseudo-hexagonal prismatic magnetite magnetosomes, as well as greigite magnetosomes. Lattice fringes were detected in the magnetosomal matrices surrounding a variety of magnetite magnetosomes and a greigite magnetosome in a variety of strains. The lattice fringes were aligned with and had widths that correlated with lattice planes in the magnetosomes. Lattice fringes oriented with the { 3 1 1 }, { 2 2 0 } , { 1 1 1 } , { 3 3 1 } and {391} lattice planes of magnetite magnetosomes and aligned with the { 2 2 2 } lattice plane of greigite magnetosomes, were recorded. {31 1 }, { 2 2 0 } and { 1 1 1 } lattice fringes were detected in pre-magnetite. This indicates that the magnetosomal matrix may act as a mother matrix for the precipitation of pre-magnetite, which transforms into magnetite. The structures of iron-sulfide magnetosomes were also analysed here. Without UV-Birradiation, iron-sulfide magnetosomes were unstable under an electron beam and appeared to rapidly transform into compounds consistent with those reported by others (Mann et al. 1990b, Farina et al. 1990 and Posfai et al. 1998a and b), which explains the contradictory reports by these authors. UV-B-irradiated iron-sulfide magnetosomes did not develop planar contrasted features within their structures and were composed of greigite solely or greigite and an unidentified surface phase, termed here pre-greigite, which is hypothesised to be a precursor in the biomineralization of greigite, because it was only detected on magnetosomes with sizes that correlated to growth. Pre-greigite is hypothesised here to be composed of a compressed form of cubic iron sulfide (d₁₁₁ = 3.06 A) and an expanded form of mackinawite (d0₁₁ = 3.03 A).
2 citations
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TL;DR: It is proposed that deltaproteobacterial magnetotactic bacteria may play an important role in iron cycling and so may represent a reservoir of iron, and be an indicator species for monitoring algal blooms in such eutrophic ecosystems.
Abstract: Magnetotactic bacteria (MTB) are a group of microorganisms that have the ability to synthesize intracellular magnetic crystals (magnetosomes). They prefer microaerobic or anaerobic aquatic sediments. Thus, there is growing interest in their ecological roles in various habitats. In this study we found co-occurrence of a large rod-shaped deltaproteobacterial magnetotactic bacterium (tentatively named LR-1) in the sediment of a Downloaded from https://academic.oup.com/femsle/advance-article-abstract/doi/10.1093/femsle/fnz253/5681391 by guest on 23 December 2019
2 citations
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TL;DR: In this paper, the authors used magnetotactic bacteria that swim along the lines of the magnetic field originating from the poles on the tip of a magnetic head to observe the magnetic structure of the tip.
Abstract: MFM images of a magnetic head and a recording medium obtained by using electrodeposited FeNi, Co, and FeCo tips show quite different features. These differences are explained by the saturation magnetization and the coercive force of the magnetic thin films electrodeposited on the W wires, In addition, we attempted to observe the magnetic structure of the tip by using magnetotactic bacteria that swim along the lines of the magnetic field originating from the poles on the tip.
2 citations
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01 Jan 2020TL;DR: Microbes are the living factories for the generation of advanced materials in the nanotechnology field and metal and microbial interactions are greatly involved in the processes like biomineralization, bioremediation, bioleaching, and microbial corrosion.
Abstract: The nanotechnology is the fast-growing field that offers a huge application in various disciplines of science and technology The nanoscale materials can be synthesized by physical, chemical, physicochemical, or biological methods All the synthesis processes except biological process have some environmental and operational constraints The biological synthesis process or green synthesis of these nanomaterials is an eco-friendly and cost-effective approach which utilizes bacteria, fungi, and plant sources Biological systems are a good producer of nanoparticles such as magnetotactic bacteria that are capable of producing magnetite (Fe3O4), while diatoms are capable of producing siliceous materials Magnetotactic bacteria produce magnetosomes which are greatly used for the immobilization of enzymes, antibodies, DNA, and RNA Metal and microbial interactions are greatly involved in the processes like biomineralization, bioremediation, bioleaching, and microbial corrosion Pseudomonas stutzeri AG259 is a metal-accumulating bacterium that has the capability to produce silver nanoparticles; fungi like Candida glabrata and Schizosaccharomyces pombe have the potential to produce cadmium sulfide particles Schizosaccharomyces pombe has been well studied for its potential to detoxify cadmium from the environment by active intracellular uptake of cadmium and its bioconversion to small iso-peptides In a summarized way, we can say microbes are the living factories for the generation of advanced materials
2 citations