Analysis of the Ultrastructure of Archaea by Electron Microscopy

Rachel, Reinhard; Meyer, Carolin; Klingl, Andreas; Gürster, Sonja; Heimerl, Thomas; Wasserburger, Nadine; Burghardt, Tillmann; Küper, Ulf; Bellack, Annett; Schopf, Simone; Wirth, Reinhard; Huber, Harald; Wanner, Gerhard

doi:10.1016/s0091-679x(10)96003-2

Cited by 39 publications

(38 citation statements)

References 48 publications

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“…Electron micrographs of negatively stained samples confirm that multiple Fig. 1 Transmission electron micrograph of an ultrathin section from an I. hospitalis cell, after cultivation in cellulose capillaries, high-pressure freezing, freeze-substitution fixation and embedding in Epon (for details, see Rachel et al 2010);…”

Section: Morphology and Cell Structurementioning

confidence: 83%

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The unusual cell biology of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis

Huber¹,

Küper

Daxer³

et al. 2012

Antonie van Leeuwenhoek

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The Crenarchaeon Ignicoccus hospitalis is an anaerobic, obligate chemolithoautotrophic hyperthermophile, growing by reduction of elemental sulfur using molecular hydrogen as electron donor. Together with Nanoarchaeum equitans it forms a unique, archaeal biocoenosis, in which I. hospitalis serves as host for N. equitans. Both organisms can be cultivated in a stable coculture which is mandatory for N. equitans but not for I. hospitalis. This strong dependence is affirmed by the fact that N. equitans obtains its lipids and amino acids from the host. I. hospitalis cells exhibit several unique features: they can adhere to surfaces by extracellular appendages ('fibers') which are not used for motility; they use a novel CO(2) fixation pathway, the dicarboxylate/4-hydroxybutyrate pathway; and they exhibit a unique cell envelope for Archaea consisting of two membranes but lacking an S-layer. These membranes form two cell compartments, a tightly packed cytoplasm surrounded by a weakly staining intermembrane compartment (IMC) with a variable width from 20 to 1,000 nm. In this IMC, many round or elongated vesicles are found which may function as carriers of lipids or proteins out of the cytoplasm. Based on immuno-EM analyses and immuno-fluorescence experiments it was demonstrated recently that the A(1)A(O) ATP synthase, the H(2):sulfur oxidoreductase complex and the acetyl-CoA synthetase (ACS) of I. hospitalis are located in its outermost membrane. Therefore, this membrane is energized and is here renamed as "outer cellular membrane" (OCM). Among all prokaryotes possessing two membranes in their cell envelope, I. hospitalis is the first organism with an energized outermost membrane and ATP synthesis outside the cytoplasm. Since DNA and ribosomes are localized in the cytoplasm, energy conservation is separated from information processing and protein biosynthesis in I. hospitalis. This raises questions concerning the function and characterization of the two membranes, the two cell compartments and of a possible ATP transfer to N. equitans.

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Section: Morphology and Cell Structurementioning

confidence: 83%

“…Transmission electron micrograph of adherent I. hospitalis cells, directly grown on carbon-coated gold grids and stained by uranyl acetate (for details, seeRachel et al 2010). Ih denotes three cells of I. hospitalis.…”

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confidence: 99%

The unusual cell biology of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis

Huber¹,

Küper

Daxer³

et al. 2012

Antonie van Leeuwenhoek

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“…We used established procedures for electron microscopic investigations (30). Cells in the logarithmic growth phase were fixed with glutardialdehyde, carefully concentrated (at a maximum of 3,000 ϫ g), and dropped onto copper grids (400 mesh).…”

Section: Methodsmentioning

confidence: 99%

The Temperature Gradient-Forming Device, an Accessory Unit for Normal Light Microscopes To Study the Biology of Hyperthermophilic Microorganisms

Mora

Bellack

Ugele

et al. 2014

Appl Environ Microbiol

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bTo date, the behavior of hyperthermophilic microorganisms in their biotope has been studied only to a limited degree; this is especially true for motility. One reason for this lack of knowledge is the requirement for high-temperature microscopy-combined, in most cases, with the need for observations under strictly anaerobic conditions-for such studies. We have developed a custom-made, low-budget device that, for the first time, allows analyses in temperature gradients up to 40°C over a distance of just 2 cm (a biotope-relevant distance) with heating rates up to ϳ5°C/s. Our temperature gradient-forming device can convert any upright light microscope into one that works at temperatures as high as 110°C. Data obtained by use of this apparatus show how very well hyperthermophiles are adapted to their biotope: they can react within seconds to elevated temperatures by starting motility-even after 9 months of storage in the cold. Using the temperature gradient-forming device, we determined the temperature ranges for swimming, and the swimming speeds, of 15 selected species of the genus Thermococcus within a few months, related these findings to the presence of cell surface appendages, and obtained the first evidence for thermotaxis in Archaea.

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“…Cryopreparation of cells was performed as originally described earlier (32), with modifications described more recently (33). Cellulose capillary tubes containing a sufficient amount of cells were transferred to 20% bovine serum albumin (BSA), cut into small pieces, and high-pressure frozen on gold specimen carriers with an EM PACT 2 high-pressure freezer (Leica Microsystems, Vienna, Austria).…”

Section: Methodsmentioning

confidence: 99%

The Iho670 Fibers of Ignicoccus hospitalis Are Anchored in the Cell by a Spherical Structure Located beneath the Inner Membrane

et al. 2014

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The Iho670 fibers of the hyperthermophilic crenarchaeon of Ignicoccus hospitalis were shown to contain several features that indicate them as type IV pilus-like structures. The application of different visualization methods, including electron tomography and the reconstruction of a three-dimensional model, enabled a detailed description of a hitherto undescribed anchoring structure of the cell appendages. It could be identified as a spherical structure beneath the inner membrane. Furthermore, pools of the fiber protein Iho670 could be localized in the inner as well as the outer cellular membrane of I. hospitalis cells and in the tubes/ vesicles in the intermembrane compartment by immunological methods. The motility of microorganisms has already been the focus of interest since van Leeuwenhoek discovered the first organisms under his self-constructed microscopes. In a letter to the Royal Society in London, he described these little animalcules as "very prettily a-moving" and stated that "the biggest sort had a very strong and swift motion, and shot through the water (or spite) like a pike does through water" (1). It took around 300 years until the bacterial flagellum, at present the best-studied prokaryotic motility organelle, could be understood in terms of structure and function. Current data show that the bacterial flagellum not only plays a role in locomotion but also is implied in the type III secretion pathway, colonization of surfaces, or the maintenance of symbiosis between prokaryotes (2-4). In addition, various other types of cell appendages and motility organelles in prokaryotes were studied under structural and functional aspects, like type IV pili, periplasmic flagella of spirochaetes, the junctional pore complex in Myxobacteria and Cyanobacteria, the ratchet structure in Flavobacteria (5), or the terminal organelle involved in adhesion in Mycoplasma pneumoniae (6,7).With the discovery of the Archaea as a third domain of life in the 1990s by Carl Woese, archaeal cell appendages received greater attention (8). In particular, the archaeal flagellum was analyzed in detail, and it was shown for Halobacterium some time ago (9, 10) and more recently for Sulfolobus (with movies taken on a thermomicroscope in our labs) that it is able to generate force by rotation (11)(12)(13)(14). Moreover, the archaeal flagellum shares some key properties with bacterial type IV pili (15-17): the heterogeneous structure of its filaments, composed of different pilin/flagellin subunits; the existence of homologous genes; a short leader peptide at the pilins/flagellins; and their cleavage by homologous signal peptidases. Like in Bacteria, the overall function of archaeal flagella is motility, although it could be shown for Bacteria as well as for Archaea that flagella also play an important role in adhesion and the formation of cell-cell contacts (11,12,(18)(19)(20).In addition to the archaeal flagellum, several other archaeal cell appendages, like fimbriae or pili, were described for a multitude of Archaea (21, 22). The cannu...

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Analysis of the Ultrastructure of Archaea by Electron Microscopy

Cited by 39 publications

References 48 publications

The unusual cell biology of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis

The unusual cell biology of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis

The Temperature Gradient-Forming Device, an Accessory Unit for Normal Light Microscopes To Study the Biology of Hyperthermophilic Microorganisms

The Iho670 Fibers of Ignicoccus hospitalis Are Anchored in the Cell by a Spherical Structure Located beneath the Inner Membrane

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