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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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TL;DR: A novel magnetotactic spirillum (XQGS-1) is identified that is phylogenetically affiliated with the Alphaproteobacteria class and supported the view that MTB are also an important microbial group for intracellular calcium carbonate and calcium phosphate biomineralization.
Abstract: Magnetotactic bacteria (MTB) are prokaryotes that form intracellular magnetite (Fe3O4) or greigite (Fe3S4) nanocrystals with tailored sizes, often in chain configurations. Such magnetic particles are each surrounded by a lipid bilayer membrane, called a magnetosome, and provide a model system for studying the formation and function of specialized internal structures in prokaryotes. Using fluorescence-coupled scanning electron microscopy, we identified a novel magnetotactic spirillum, XQGS-1, from freshwater Xingqinggong Lake, Xi'an City, Shaanxi Province, China. Phylogenetic analyses based on 16S rRNA gene sequences indicate that strain XQGS-1 represents a novel genus of the Alphaproteobacteria class in the Proteobacteria phylum. Transmission electron microscopy analyses reveal that strain XQGS-1 forms on average 17 ± 3 magnetite magnetosome particles with an ideal truncated octahedral morphology, with an average length and width of 88.3 ± 11.7 nm and 83.3 ± 11.0 nm, respectively. They are tightly organized into a single chain along the cell long axis close to the concave side of the cell. Intrachain magnetic interactions likely result in these large equidimensional magnetite crystals behaving as magnetically stable single-domain particles that enable bacterial magnetotaxis. Combined structural and chemical analyses demonstrate that XQGS-1 cells also biomineralize intracellular amorphous calcium phosphate (2 to 3 granules per cell; 90.5- ± 19.3-nm average size) and weakly crystalline calcium carbonate (2 to 3 granules per cell; 100.4- ± 21.4-nm average size) in addition to magnetite. Our results expand the taxonomic diversity of MTB and provide evidence for intracellular calcium phosphate biomineralization in MTB. IMPORTANCE Biomineralization is a widespread process in eukaryotes that form shells, teeth, or bones. It also occurs commonly in prokaryotes, resulting in more than 60 known minerals formed by different bacteria under wide-ranging conditions. Among them, magnetotactic bacteria (MTB) are remarkable because they might represent the earliest organisms that biomineralize intracellular magnetic iron minerals (i.e., magnetite [Fe3O4] or greigite [Fe3S4]). Here, we report a novel magnetotactic spirillum (XQGS-1) that is phylogenetically affiliated with the Alphaproteobacteria class. In addition to magnetite crystals, XQGS-1 cells form intracellular submicrometer calcium carbonate and calcium phosphate granules. This finding supports the view that MTB are also an important microbial group for intracellular calcium carbonate and calcium phosphate biomineralization.
4 citations
TL;DR: An accurate quantification of magnetic force microscope images has been accomplished as discussed by the authors, using magnetosomes produced by magnetotactic bacteria, an ideal micromagnetic model system, were the specimens used for the quantification (a moment on the order of 10 −13 emu).
4 citations
TL;DR: In this paper, the magnetotactic bacterium, magnetospirillum magneticum AMB-1, was applied in the microbial recovery of gold from plating waste.
Abstract: Magnetotactic bacteria are a unique species of bacteria, commonly recognized by the presence of magnetic particles within them. These intracellular, nanosized magnetic particles enable the bacteria to migrate and be manipulated by magnetic force. To date, magnetotactic bacteria have been widely researched and implemented in various biotechnology based applications. In this study, as an extension to its applications, the magnetotactic bacterium, Magnetospirillum magneticum AMB-1, was applied in the microbial recovery of gold from plating waste. M. magneticum AMB-1 successfully precipitated approximately 42% and 100% of gold from growth medium containing 10 µM gold and from a mixture of plating waste/growth medium containing 0.4 µM gold, respectively. These observations and results strongly suggests that an important advancement in biorecovery of rare metals and bioremediation of toxic metals was achieved in which the application of whole cell bacteria, and direct precipitation of metals from plating waste using magnetotactic bacteria was performed for the first time.
4 citations
3 citations