The Periplasmic Nitrate Reductase Nap Is Required for Anaerobic Growth and Involved in Redox Control of Magnetite Biomineralization in Magnetospirillum gryphiswaldense

Li, Yingjie; Katzmann, Emanuel; Borg, Sarah; Schüler, Dirk

doi:10.1128/jb.00903-12

Cited by 92 publications

(126 citation statements)

References 66 publications

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“…It is interesting to note that these latter elements are known to be cofactors of metalloenzymes (32) that are essential for bacterial growth and metabolism. Molybdenum is indeed required for nitrate reductase enzymatic activity, which has been reported in AMB-1 and other MTB strains (33,34). The nitrate reductase reduces nitrate for cell respiration and is also necessary for the magnetite biomineralization in strains MSR-1 and AMB-1 (33, 34).…”

Section: Resultsmentioning

confidence: 97%

Chemical signature of magnetotactic bacteria

Amor

Busigny

Durand-Dubief

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.

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Section: Resultsmentioning

confidence: 97%

Chemical signature of magnetotactic bacteria

Amor

Busigny

Durand-Dubief

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…1a,b). In the absence of oxygen, cells developed distinct tactic bands at millimolar concentrations in gradients of nitrate (an alternative terminal electron acceptor for anaerobic respiration 14 , Supplementary Fig. 1a), indicating that the strong aerotaxis behaviour is part of a general energy taxis response similar to that identified in the microaerophilic A. brasiliense and other bacteria [15][16][17][18] .…”

Section: Resultsmentioning

confidence: 98%

Polarity of bacterial magnetotaxis is controlled by aerotaxis through a common sensory pathway

2014

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“…Recently, it has been shown that dissimilatory denitrification is essential to form proper magnetosomes under microaerobic conditions (51). A nitrate reductase nap mutant formed small and poorly crystallized magnetite reminiscent of that of the ftsZm mutant but, in contrast to the latter, also in the presence of nitrate.…”

Section: Discussionmentioning

confidence: 99%

The FtsZ-Like Protein FtsZm of Magnetospirillum gryphiswaldense Likely Interacts with Its Generic Homolog and Is Required for Biomineralization under Nitrate Deprivation

et al. 2014

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dMidcell selection, septum formation, and cytokinesis in most bacteria are orchestrated by the eukaryotic tubulin homolog FtsZ. The alphaproteobacterium Magnetospirillum gryphiswaldense (MSR-1) septates asymmetrically, and cytokinesis is linked to splitting and segregation of an intracellular chain of membrane-enveloped magnetite crystals (magnetosomes). In addition to a generic, full-length ftsZ gene, MSR-1 contains a truncated ftsZ homolog (ftsZm) which is located adjacent to genes controlling biomineralization and magnetosome chain formation. We analyzed the role of FtsZm in cell division and biomineralization together with the full-length MSR-1 FtsZ protein. Our results indicate that loss of FtsZm has a strong effect on microoxic magnetite biomineralization which, however, could be rescued by the presence of nitrate in the medium. Fluorescence microscopy revealed that FtsZm-mCherry does not colocalize with the magnetosome-related proteins MamC and MamK but is confined to asymmetric spots at midcell and at the cell pole, coinciding with the FtsZ protein position. In Escherichia coli, both FtsZ homologs form distinct structures but colocalize when coexpressed, suggesting an FtsZdependent recruitment of FtsZm. In vitro analyses indicate that FtsZm is able to interact with the FtsZ protein. Together, our data suggest that FtsZm shares key features with its full-length homolog but is involved in redox control for magnetite crystallization. Magnetotactic bacteria (MTB) produce magnetosomes to navigate along Earth's magnetic field lines toward growth-favoring microoxic environments. Magnetosomes consist of nanometer-sized membrane-enveloped magnetite crystals and have recently emerged as a model system to study formation of prokaryotic organelles (1). In the alphaproteobacterium Magnetospirillum gryphiswaldense MSR-1 (in the following, referred to as MSR-1) and related magnetospirilla, the intracellular organelles are attached to a filamentous cytoskeletal structure formed by the actinlike MamK protein (2, 3, 4) which assembles magnetosomes into a cohesive chain (5). This magnetosome chain generates a magnetic moment which aligns the cell in external magnetic fields. In order to be cleaved evenly during cytokinesis and to be equipartitioned to daughter cells, the magnetosome chain is positioned at midcell. After cytokinesis, daughter chains are translocated to midcell again, suggesting that chain separation and relocalization are coordinated with the cell cycle.A crucial factor for midcell determination and septum formation in most bacteria is the conserved tubulin homolog FtsZ. FtsZ monomers assemble in a GTP-dependent manner to form protofilaments that align into higher-ordered structures by lateral selfinteraction assisted by accessory proteins. The FtsZ polymers are membrane tethered by C-terminal interaction with FtsA and build ring-or arc-like structures at future division sites (6). These FtsZ assemblies recruit further cell division proteins to finally build the divisome complex (7,8). Several factors have ...

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The Periplasmic Nitrate Reductase Nap Is Required for Anaerobic Growth and Involved in Redox Control of Magnetite Biomineralization in Magnetospirillum gryphiswaldense

Cited by 92 publications

References 66 publications

Chemical signature of magnetotactic bacteria

Chemical signature of magnetotactic bacteria

Polarity of bacterial magnetotaxis is controlled by aerotaxis through a common sensory pathway

The FtsZ-Like Protein FtsZm of Magnetospirillum gryphiswaldense Likely Interacts with Its Generic Homolog and Is Required for Biomineralization under Nitrate Deprivation

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