Magnetotactic bacteria

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

Genetic Analysis of Magnetosome Biomineralization

Abstract: Magnetite crystals produced by magnetotactic bacteria (MTB) have uniform species–specific morphologies and sizes, which are mostly unknown from inorganic systems. This indicates that biomineralization in magnetosomes is a process with genetic control over the accumulation of iron, the deposition of the magnetic crystal within a specific compartment, as well as their intracellular assembly and alignment into chain-like structures. Our understanding of the molecular and genetic basis of magnetosome formation has substantially improved during the last few years due to the progress in genome analysis and the development of advanced genetic techniques to study MTB.

Generation of multifunctional magnetic nanoparticles with amplified catalytic activities by genetic expression of enzyme arrays on bacterial magnetosomes

Abstract: Due to their highly regulated biosynthesis, magnetosomes biomineralized by magnetotactic bacteria represent natural magnetic nanoparticles with unique physical and chemical properties. They consist of a magnetite core that is surrounded by a biological membrane and are therefore reminiscent to magnetic “core–shell” nanoparticles. Their usability in many nanotechnological and biomedical applications would be further improved by the introduction of additional catalytic and imaging modalities. Here, a new in vivo strategy is explored for magnetosome display of foreign polypeptides with maximized protein-to-particle ratios. Arrays of up to five monomers of the model enzyme glucuronidase GusA plus the additional fluorophore mEGFP are genetically fused as single large hybrid proteins to highly expressed magnetosome protein anchors. In total, about 190 GusA monomers are covalently attached to individual particles. Assuming layers of GusA rows surrounding the particles, the monomers would thus cover up to 90% of the magnetosome surface. The approach generates nanoparticles that exhibit magnetism, fluorescence, and stable catalytic activities, which are stepwise increased with the number of GusA monomers. In summary, multicopy expression of arrayed foreign proteins represents a powerful methodology for the biosynthesis of tailored biohybrid magnetic nanoparticles with several genetically encoded and tunable functionalities.

Bacterial community structure and novel species of magnetotactic bacteria in sediments from a seamount in the Mariana volcanic arc.

Abstract: Seamounts are undersea mountains rising abruptly from the sea floor and interacting dynamically with underwater currents. They represent unique biological habitats with various microbial community structures. Certain seamount bacteria form conspicuous extracellular iron oxide structures, including encrusted stalks, flattened bifurcating tubes, and filamentous sheaths. To extend our knowledge of seamount ecosystems, we performed an integrated study on population structure and the occurrence of magnetotactic bacteria (MTB) that synthesize intracellular iron oxide nanocrystals in sediments of a seamount in the Mariana volcanic arc. We found Proteobacteria dominant at 13 of 14 stations, but ranked second in abundance to members of the phylum Firmicutes at the deep-water station located on a steep slope facing the Mariana-Yap Trench. Live MTB dwell in biogenic sediments from all 14 stations ranging in depth from 238 to 2,023 m. Some magnetotactic cocci possess the most complex flagellar apparatus yet reported; 19 flagella are arranged in a 3:4:5:4:3 array within a flagellar bundle. Phylogenetic analysis of 16S rRNA gene sequences identified 16 novel species of MTB specific to this seamount. Together the results obtained indicate that geographic properties of the seamount stations are important in shaping the bacterial community structure and the MTB composition.