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Wei-Jia Zhang, Sheng-Da Zhang, Long-Fei Wu
Magnetococcus massalia strain MO-1 represents a group of fast-swimming marine magnetotactic coccoid-ovoid bacteria. They show polar magnetotaxis behavior in uniform magnetic field. MO-1 cells swim forward constantly with rare stop. When they meet obstacles, MO-1 cells could squeeze through or circumvent the obstacles. Here, we describe the methods for characterization of magnetotactic behaviors of MO-1 cells using adapted spectrophotometer and microscope mounted with magnetic fields.
2017: Methods in Molecular Biology
Wei Lin, Greig A Paterson, Qiyun Zhu, Yinzhao Wang, Evguenia Kopylova, Ying Li, Rob Knight, Dennis A Bazylinski, Rixiang Zhu, Joseph L Kirschvink, Yongxin Pan
Microbes that synthesize minerals, a process known as microbial biomineralization, contributed substantially to the evolution of current planetary environments through numerous important geochemical processes. Despite its geological significance, the origin and evolution of microbial biomineralization remain poorly understood. Through combined metagenomic and phylogenetic analyses of deep-branching magnetotactic bacteria from the Nitrospirae phylum, and using a Bayesian molecular clock-dating method, we show here that the gene cluster responsible for biomineralization of magnetosomes, and the arrangement of magnetosome chain(s) within cells, both originated before or near the Archean divergence between the Nitrospirae and Proteobacteria This phylogenetic divergence occurred well before the Great Oxygenation Event...
February 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
Hongwei Mo, Lili Liu, Jiao Zhao
Magnetotactic bacteria is a kind of polyphyletic group of prokaryotes with the characteristics of magnetotaxis that make them orient and swim along geomagnetic field lines. Its distinct biology characteristics are useful to design new optimization technology. In this paper, a new bionic optimization algorithm named Magnetotactic Bacteria Moment Migration Algorithm (MBMMA) is proposed. In the proposed algorithm, the moments of a chain of magnetosomes are considered as solutions. The moments of relative good solutions can migrate each other to enhance the diversity of the MBMMA...
January 2017: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Hong Wang, Martin Pumera
Self-propelled autonomous nano and micromotors are devices which in many aspects mimic living organisms: they take chemical energy from the environment and convert it to motion; they are capable of phototaxis, chemotaxis and magnetotaxis, following the gradient of fuel, a magnetic field or light. There is an immense spectrum of possible applications of these devices, ranging from environmental remediation to the biomedical field. All of these developments depend on the materials used and there has been intensive development of materials allowing more efficient propulsion, phototaxis, chemotaxis and enhanced applications of these devices...
February 1, 2017: Nanoscale
Pedro Leão, Yi-Ran Chen, Fernanda Abreu, Mingling Wang, Wei-Jia Zhang, Ke Zhou, Tian Xiao, Long-Fei Wu, Ulysses Lins
Magnetotactic multicellular prokaryotes (MMPs) consist of unique microorganisms formed by genetically identical Gram-negative bacterial that live as a single individual capable of producing magnetic nano-particles called magnetosomes. Two distinct morphotypes of MMPs are known: spherical MMPs (sMMPs) and ellipsoidal MMPs (eMMPs). sMMPs have been extensively characterized, but less information exists for eMMPs. Here, we report the ultrastructure and organization as well as gene clusters responsible for magnetosome and flagella biosynthesis in the magnetite magnetosome producer eMMP Candidatus Magnetananas rongchenensis...
January 24, 2017: Environmental Microbiology
Fei Peng, Yingfeng Tu, Yongjun Men, Jan C M van Hest, Daniela A Wilson
With a convenient bottom-up approach, magnetic metallic nickel is grown in situ of a supramolecular nanomotor using the catalytic activities of preloaded platinum nanoparticles. After introducing magnetic segments, simultaneous guidance and steering of catalytically powered motors with additional magnetic fields are achieved. Guided motion in a tissue model is demonstrated.
November 28, 2016: Advanced Materials
Roger Duarte de Melo, Daniel Acosta-Avalos
'Candidatus Magnetoglobus multicellularis' is the most studied multicellular magnetotactic prokaryote. It presents a light-dependent photokinesis: green light decreases the translation velocity whereas red light increases it, in comparison to blue and white light. The present article shows that radio-frequency electromagnetic fields cancel the light effect on photokinesis. The frequency to cancel the light effect corresponds to the Zeeman resonance frequency (DC magnetic field of 4 Oe and radio-frequency of 11...
February 2017: Antonie Van Leeuwenhoek
Bahareh Kherzi, Martin Pumera
Self-propelled autonomous nano/micromotors are in the forefront of current materials science and technology research. These small machines convert chemical energy from the environment into propulsion, and they can move autonomously in the environment and are capable of chemotaxis or magnetotaxis. They can be used for drug delivery, microsurgeries or environmental remediation. It is of immense interest from a future biomedical application point of view to understand the motion of the nano/micromotors in microfluidic channels...
October 14, 2016: Nanoscale
Pedro Leão, Lia C R S Teixeira, Jefferson Cypriano, Marcos Farina, Fernanda Abreu, Dennis A Bazylinski, Ulysses Lins
UNLABELLED: Magnetotactic bacteria (MTB) comprise a phylogenetically diverse group of prokaryotes capable of orienting and navigating along magnetic field lines. Under oxic conditions, MTB in natural environments in the Northern Hemisphere generally display north-seeking (NS) polarity, swimming parallel to the Earth's magnetic field lines, while those in the Southern Hemisphere generally swim antiparallel to magnetic field lines (south-seeking [SS] polarity). Here, we report a population of an uncultured, monotrichously flagellated, and vibrioid MTB collected from a brackish lagoon in Brazil in the Southern Hemisphere that consistently exhibits NS polarity...
September 15, 2016: Applied and Environmental Microbiology
Natalie Zeytuni, Samuel Cronin, Christopher T Lefèvre, Pascal Arnoux, Dror Baran, Zvi Shtein, Geula Davidov, Raz Zarivach
MamA is a highly conserved protein found in magnetotactic bacteria (MTB), a diverse group of prokaryotes capable of navigating according to magnetic fields - an ability known as magnetotaxis. Questions surround the acquisition of this magnetic navigation ability; namely, whether it arose through horizontal or vertical gene transfer. Though its exact function is unknown, MamA surrounds the magnetosome, the magnetic organelle embedding a biomineralised nanoparticle and responsible for magnetotaxis. Several structures for MamA from a variety of species have been determined and show a high degree of structural similarity...
2015: PloS One
Geula Davidov, Frank D Müller, Jens Baumgartner, Ronit Bitton, Damien Faivre, Dirk Schüler, Raz Zarivach
Magnetotactic bacteria (MTB) are a diverse group of aquatic bacteria that have the magnetotaxis ability to align themselves along the geomagnetic field lines and to navigate to a microoxic zone at the bottom of chemically stratified natural water. This special navigation is the result of a unique linear assembly of a specialized organelle, the magnetosome, which contains a biomineralized magnetic nanocrystal enveloped by a cytoplasmic membrane. The Magnetospirillum gryphiswaldense MtxA protein (MGR_0208) was suggested to play a role in bacterial magnetotaxis due to its gene location in an operon together with putative signal transduction genes...
2015: Frontiers in Molecular Biosciences
Michalis Chariaou, Lilah Rahn-Lee, Jessica Kind, Inés García-Rubio, Arash Komeili, Andreas U Gehring
Magnetotactic bacteria (MTB) build magnetic nanoparticles in chain configuration to generate a permanent dipole in their cells as a tool to sense the Earth's magnetic field for navigation toward favorable habitats. The majority of known MTB align their nanoparticles along the magnetic easy axes so that the directions of the uniaxial symmetry and of the magnetocrystalline anisotropy coincide. Desulfovibrio magneticus sp. strain RS-1 forms bullet-shaped magnetite nanoparticles aligned along their (100) magnetocrystalline hard axis, a configuration energetically unfavorable for formation of strong dipoles...
March 10, 2015: Biophysical Journal
Isaac Macwan, Zihe Zhao, Omar Sobh, Prabir Patra
Magnetospirillum magneticum (AMB-1), which belong to alpha-protobacterium are gram-negative, single-celled prokaryotic organisms consisting of a lash-like cellular appendage called flagella. These filamentous structures are made up of a protein called flagellin that in turn consist of four sub-domains, two inner domains (D0, D1) made up of alpha-helices and two outer domains (D2, D3) made up of beta sheets. It is wrapped in a helical fashion around the longitudinal filament with the outermost sub-domain (D3) exposed to the surrounding environment...
2014: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Lina M González, Warren C Ruder, Aaron P Mitchell, William C Messner, Philip R LeDuc
Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to environmental cues such as chemical gradients (chemotaxis) and oxygen gradients (aerotaxis). Magnetotaxis is found in magnetotactic bacteria and it is defined as the passive alignment of these cells to the geomagnetic field along with active swimming. Herein we show that Magnetospirillum magneticum (AMB-1) show a unique set of responses that indicates they sense and respond not only to the direction of magnetic fields by aligning and swimming, but also to changes in the magnetic field or magnetic field gradients...
June 2015: ISME Journal
Felix Popp, Judith P Armitage, Dirk Schüler
Most motile bacteria navigate within gradients of external chemical stimuli by regulating the length of randomly oriented swimming episodes. Magnetotactic bacteria are characterized by chains of intracellular ferromagnetic nanoparticles and their ability to sense the geomagnetic field, which is believed to facilitate directed motion, but is not well understood at the behavioural and molecular level. Here, we show that cells of Magnetospirillum gryphiswaldense unexpectedly display swimming polarity that depends on aerotactic signal transduction through one of its four chemotaxis operons (cheOp1)...
2014: Nature Communications
Dennis A Bazylinski, Christopher T Lefèvre
Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic-anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI...
2013: Life
Xuegang Mao, Ramon Egli, Nikolai Petersen, Marianne Hanzlik, Xiuming Liu
Magnetotactic bacteria (MTB) use passive alignment with the Earth magnetic field as a mean to increase their navigation efficiency in horizontally stratified environments through what is known as magneto-aerotaxis (M-A). Current M-A models have been derived from MTB observations in aqueous environments, where a >80% alignment with inclined magnetic field lines produces a one-dimensional search for optimal living conditions. However, the mean magnetic alignment of MTB in their most widespread living environment, i...
2014: PloS One
Mathieu Bennet, Aongus McCarthy, Dmitri Fix, Matthew R Edwards, Felix Repp, Peter Vach, John W C Dunlop, Metin Sitti, Gerald S Buller, Stefan Klumpp, Damien Faivre
The response of cells to changes in their physico-chemical micro-environment is essential to their survival. For example, bacterial magnetotaxis uses the Earth's magnetic field together with chemical sensing to help microorganisms move towards favoured habitats. The studies of such complex responses are lacking a method that permits the simultaneous mapping of the chemical environment and the response of the organisms, and the ability to generate a controlled physiological magnetic field. We have thus developed a multi-modal microscopy platform that fulfils these requirements...
2014: PloS One
Suzanne C Dufour, Jason R Laurich, Rebecca T Batstone, Bonita McCuaig, Alexander Elliott, Kristin M Poduska
Bacteria containing magnetosomes (protein-bound nanoparticles of magnetite or greigite) are common to many sedimentary habitats, but have never been found before to live within another organism. Here, we show that octahedral inclusions in the extracellular symbionts of the marine bivalve Thyasira cf. gouldi contain iron, can exhibit magnetic contrast and are most likely magnetosomes. Based on 16S rRNA sequence analysis, T. cf. gouldi symbionts group with symbiotic and free-living sulfur-oxidizing, chemolithoautotrophic gammaproteobacteria, including the symbionts of other thyasirids...
December 2014: ISME Journal
Xuejun Zhu, Xin Ge, Ning Li, Long-Fei Wu, Chunxiong Luo, Qi Ouyang, Yuhai Tu, Guanjun Chen
The mechanism of how magnetotactic bacteria navigate along the magnetic field has been a puzzle. Two main models disagree on whether the magnetotactic behavior results from passive alignment with the magnetic field or active sensing of the magnetic force. Here, we quantitatively studied the swimming patterns of Magnetospirillum magneticum AMB-1 cells to understand the origin of their magnetotactic behaviors. Single-cell tracking and swimming pattern analysis showed that the cells follow a mixed run-reverse-tumble pattern...
July 24, 2014: Integrative Biology: Quantitative Biosciences From Nano to Macro
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