North-Seeking Magnetotactic Gammaproteobacteria in the Southern Hemisphere.
Pedro Leão,Lia C. R. S. Teixeira,Jefferson Cypriano,Marcos Farina,Fernanda Abreu,Dennis A. Bazylinski,Ulysses Lins +6 more
TLDR
A population of an uncultured, monotrichously flagellated, and vibrioid MTB collected from a brackish lagoon in Brazil in the Southern Hemisphere that consistently exhibits north-seeking polarity is reported, supporting the idea that magnetotaxis is more complex than previously thought.Abstract:
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 Earth9s 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. Cells of this organism were mainly located below the oxic-anoxic interface (OAI), suggesting it is capable of some type of anaerobic metabolism. Magnetosome crystalline habit and composition were consistent with elongated prismatic magnetite (Fe 3 O 4 ) particles. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that this organism belongs to a distinct clade of the Gammaproteobacteria class. The presence of NS MTB in the Southern Hemisphere and the previously reported finding of SS MTB in the Northern Hemisphere reinforce the idea that magnetotaxis is more complex than we currently understand and may be modulated by factors other than O 2 concentration and redox gradients in sediments and water columns.
IMPORTANCE Magnetotaxis is a navigational mechanism used by magnetotactic bacteria to move along geomagnetic field lines and find an optimal position in chemically stratified sediments. For that, magnetotactic bacteria swim parallel to the geomagnetic field lines under oxic conditions in the Northern Hemisphere, whereas those in the Southern Hemisphere swim antiparallel to magnetic field lines. A population of uncultured vibrioid magnetotactic bacteria was discovered in a brackish lagoon in the Southern Hemisphere that consistently swim northward, i.e., the opposite of the overwhelming majority of other Southern Hemisphere magnetotactic bacteria. This finding supports the idea that magnetotaxis is more complex than previously thought.read more
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Diversity and ecology of and biomineralization by magnetotactic bacteria
TL;DR: This study conducted a search of public metagenomic databases and identified six novel magnetosome gene cluster-containing genomic fragments affiliated with the Deltaproteinobacteria and Gammaproteobacteria classes of the Proteobacteria phylum, the Nitrospirae phylum and the Planctomycetes phylum from the deep subseafloor, marine oxygen minimum zone, groundwater biofilm and estuary sediment.
Journal ArticleDOI
Swimming with magnets: From biological organisms to synthetic devices
Stefan Klumpp,Stefan Klumpp,Christopher T. Lefèvre,Mathieu Bennet,Damien Faivre,Damien Faivre +5 more
TL;DR: The field of the magnetic microswimmers is reviewed, which as indicated by the adjective, represents a dedicated branch of the general microswimming where magnetism plays a role either for the orientation or for the locomotion of the swimmers.
Journal ArticleDOI
Ectosymbiotic bacteria at the origin of magnetoreception in a marine protist
Caroline L. Monteil,David Vallenet,Nicolas Menguy,Karim Benzerara,Valérie Barbe,Stéphanie Fouteau,Corinne Cruaud,Magali Floriani,Eric Viollier,Géraldine Adryanczyk,Nathalie Leonhardt,Damien Faivre,Damien Faivre,David Pignol,Purificación López-García,Richard J. Weld,Christopher T. Lefèvre +16 more
TL;DR: A mutualistic symbiosis between a non-motile, magnetic deltaproteobacterium and a protist, resulting in eukaryotic magnetoreception in marine anoxic sediments is identified, suggesting a historical acquisition of magnetoreceptions by a euglenozoan ancestor from Deltaproteobacteria followed by subsequent diversification.
Journal ArticleDOI
On the origin of microbial magnetoreception.
Wei Lin,Joseph L. Kirschvink,Joseph L. Kirschvink,Greig A. Paterson,Greig A. Paterson,Dennis A. Bazylinski,Yongxin Pan +6 more
TL;DR: It is proposed that initial biomineralization of intracellular iron nanoparticles in early life evolved as a mechanism for mitigating the toxicity of reactive oxygen species (ROS), as ultraviolet radiation and free-iron-generated ROS would have been a major environmental challenge for life on early Earth.
Journal ArticleDOI
Iron-biomineralizing organelle in magnetotactic bacteria: function, synthesis and preservation in ancient rock samples.
Matthieu Amor,François P. Mathon,François P. Mathon,Caroline L. Monteil,Vincent Busigny,Vincent Busigny,Christopher T. Lefèvre +6 more
TL;DR: An overview of the mechanisms leading to iron mineralization in MTB is provided, their distribution in the environment is described, and the possible function of the magnetite and greigite nanoparticles are discussed.
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