Study of the motion of magnetotactic bacteria

Nogueiral, Flavio S.; Barros, H. G. P. Lins de

doi:10.1007/bf00216826

Cited by 39 publications

(34 citation statements)

References 15 publications

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“…High velocity is believed to help bacteria locate the nutrient resources in a microenvironment quickly (38). MWB-1 exhibits a helical trajectory similar to those of Alphaproteobacteria magnetotactic cocci harboring a single magnetosome chain (26,39,40) and LO-1 in the Nitrospirae (27). The helical trajectories of magnetotactic cocci are due to the inclination between the magnetosome chain and the flagellar propulsion axis (40).…”

Section: Methodsmentioning

confidence: 99%

Newly Isolated but Uncultivated Magnetotactic Bacterium of the Phylum Nitrospirae from Beijing, China

Lin

Pan

2012

Appl Environ Microbiol

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Magnetotactic bacteria (MTB) in the phylum Nitrospirae synthesize up to hundreds of intracellular bullet-shaped magnetite magnetosomes. In the present study, a watermelon-shaped magnetotactic bacterium (designated MWB-1) from Lake Beihai in Beijing, China, was characterized. This uncultivated microbe was identified as a member of the phylum Nitrospirae and represents a novel phylogenetic lineage with >6% 16S rRNA gene sequence divergence from all currently described MTB. MWB-1 contained 200 to 300 intracellular bullet-shaped magnetite magnetosomes and showed a helical swimming trajectory under homogeneous magnetic fields; its magnetotactic velocity decreased with increasing field strength, and vice versa. A robust phylogenetic framework for MWB-1 and all currently known MTB in the phylum Nitrospirae was constructed utilizing maximumlikelihood and Bayesian algorithms, which yielded strong evidence that the Nitrospirae MTB could be divided into four well-supported groups. Considering its population densities in sediment and its high numbers of magnetosomes, MWB-1 was estimated to account for more than 10% of the natural remanent magnetization of the surface sediment. Taken together, the results of this study suggest that MTB in the phylum Nitrospirae are more diverse than previously realized and can make important contributions to the sedimentary magnetization in particular environments. Biomineralization of magnetic minerals has been discovered in a broad range of organisms, including birds, fishes, mollusks, insects, and microorganisms (23,53,55). A typical example of biomineralization is found in magnetotactic bacteria (MTB), a morphologically and phylogenetically diverse group of microorganisms that form special intracellular organelles, called magnetosomes (3, 5). Magnetosomes are membrane-enveloped, nanosized, high-purity crystals of iron oxide magnetite and/or iron sulfide greigite, usually arranged into one or more linear chains (21). These specific organelles help MTB to sense and swim along the earth's magnetic field, a behavior known as magnetotaxis (8). In conjunction with aerotaxis and chemotaxis, magnetotaxis facilitates the location of MTB to their favorable positions in vertical chemical gradients in the oxic-anoxic transition zone (OATZ) (11,40). The ubiquity and abundance of MTB near the OATZ suggest their potentially important roles in the geochemical cycling of iron and sulfur in nature (48). Molecular approaches based on 16S rRNA gene sequencing have provided evidence for the phylogenetic heterogeneity of MTB. Most discovered MTB are affiliated with the Alphaproteobacteria, but MTB belonging to the Gammaproteobacteria, the Deltaproteobacteria, and Nitrospirae have also been described (2, 28).One of the most intriguing examples of MTB is "Candidatus Magnetobacterium bavaricum," a magnetite-producing MTB within the deep-branching bacterial phylum Nitrospirae that was first discovered in Lake Chiemsee in Upper Bavaria, Germany (49, 54). "Ca. Magnetobacterium bavaricum" is a large, rod-shaped bact...

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Section: Methodsmentioning

confidence: 99%

Newly Isolated but Uncultivated Magnetotactic Bacterium of the Phylum Nitrospirae from Beijing, China

Lin

Pan

2012

Appl Environ Microbiol

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“…Most bacteria, including magnetotactic bacteria, display helical tracks (Fenchel, 1994;Nogueira and Lins de Barros, 1995). Flagella of magnetotactic bacteria are short, i.e., less than one helical turn of the filament (Balkwill et al, 1981;Nogueira and Lins de Barros, 1995). The short flagella of magnetotactic bacteria force the bacterium body to rotate around its axis while they swim propelled by the flagella.…”

Section: Discussionmentioning

confidence: 98%

“…The coordinated short flagella of the MMP would account for the observed sense of rotation of the trajectory (clockwise) along with the rotation of the microorganism's body during swimming (Keim et al, in press). Most bacteria, including magnetotactic bacteria, display helical tracks (Fenchel, 1994;Nogueira and Lins de Barros, 1995). Flagella of magnetotactic bacteria are short, i.e., less than one helical turn of the filament (Balkwill et al, 1981;Nogueira and Lins de Barros, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Different than other bacteria, the flagellar filaments in magnetotactic bacteria are generally shorter than one helix turn (Balkwill et al, 1980;Nogueira and Lins de Barros, 1995). Flagella tufts in uncultured magnetotactic cocci were observed to emerge from the cell in a disc-shaped structure (Blakemore, 1975), in a depression or without any of these accessory structures (Moench, 1988).…”

Section: Introductionmentioning

confidence: 96%

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Flagellar apparatus of south‐seeking many‐celled magnetotactic prokaryotes

Silva

Abreu

Almeida

et al. 2006

Microscopy Res & Technique

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Magnetotactic bacteria orient and migrate along geomagnetic field lines. Each cell contains membrane-enclosed, nano-scale, iron-mineral particles called magnetosomes that cause alignment of the cell in the geomagnetic field as the bacteria swim propelled by flagella. In this work we studied the ultrastructure of the flagellar apparatus in many-celled magnetotactic prokaryotes (MMP) that consist of several Gram-negative cells arranged radially around an acellular compartment. Flagella covered the organism surface, and were observed exclusively at the portion of each cell that faced the environment. The flagella were helical tubes never as long as a complete turn of the helix. Flagellar filaments varied in length from 0.9 to 3.8 micro m (average 2.4 +/- 0.5 micro m, n = 150) and in width from 12.0 to 19.5 nm (average 15.9 +/- 1.4 nm, n = 52), which is different from previous reports for similar microorganisms. At the base of the flagella, a curved hook structure slightly thicker than the flagellar filaments was observed. In freeze-fractured samples, macromolecular complexes about 50 nm in diameter, which possibly corresponded to part of the flagella basal body, were observed in both the P-face of the cytoplasmic membrane and the E-face of the outer membrane. Transmission electron microscopy showed that magnetosomes occurred in planar groups in the cytoplasm close and parallel to the organism surface. A striated structure, which could be involved in maintaining magnetosomes fixed in the cell, was usually observed running along magnetosome chains. The coordinated movement of the MMP depends on the interaction between the flagella of each cell with the flagella of adjacent cells of the microorganism.

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“…Many magnetotactic cocci are observed to make rocking motions as they swim. This would occur if the magnetic dipole in each cell were not perfectly aligned along the axis of motility of the cell, and also because flagella in magnetotactic bacteria are short (similar to or smaller than one helical turn) when compared to Escherichia coli that has very long flagella, and follows straight trajectories (Nogueira and Lins de Barros 1995).…”

Section: Discussionmentioning

confidence: 99%

Crystal habits and magnetic microstructures of magnetosomes in coccoid magnetotactic bacteria

Lins

McCartney

Farina

et al. 2006

An. Acad. Bras. Ciênc.

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We report on the application of off-axis electron holography and high-resolution TEM to study the crystal habits of magnetosomes and magnetic microstructure in two coccoid morphotypes of magnetotactic bacteria collected from a brackish lagoon at Itaipu, Brazil. Itaipu-1, the larger coccoid organism, contains two separated chains of unusually large magnetosomes; the magnetosome crystals have roughly square projections, lengths up to 250 nm and are slightly elongated along [111] (width/length ratio of about 0.9). Itaipu-3 magnetosome crystals have lengths up to 120 nm, greater elongation along [111] (width/length ∼ 0.6), and prominent corner facets. The results show that Itaipu-1 and Itaipu-3 magnetosome crystal habits are related, differing only in the relative sizes of their crystal facets. In both cases, the crystals are aligned with their [111] elongation axes parallel to the chain direction. In Itaipu-1, but not Itaipu-3, crystallographic positioning perpendicular to [111] of successive crystals in the magnetosome chain appears to be under biological control. Whereas the large magnetosomes in Itaipu-1 are metastable, single-magnetic domains, magnetosomes in Itaipu-3 are permanent, single-magnetic domains, as in most magnetotactic bacteria.

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Study of the motion of magnetotactic bacteria

Cited by 39 publications

References 15 publications

Newly Isolated but Uncultivated Magnetotactic Bacterium of the Phylum Nitrospirae from Beijing, China

Newly Isolated but Uncultivated Magnetotactic Bacterium of the Phylum Nitrospirae from Beijing, China

Flagellar apparatus of south‐seeking many‐celled magnetotactic prokaryotes

Crystal habits and magnetic microstructures of magnetosomes in coccoid magnetotactic bacteria

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