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Chapter 6 : Morphology and Ultrastructure

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Abstract:

This chapter concentrates on the ultrastructural features of , with limited descriptions of some of the more unusual features seen in the other members of this genus. Certain aspects of the ultrastructural detail of the helicobacters, e.g., sheathed flagella and surface urease, have been implicated in their ability to survive in hostile environments such as the acidic gastric mucosa and their ability to induce disease. Generally it is considered that the spiral morphology and flagella are essential for colonization of gastric and intestinal mucus. By excluding flagellin, urease, and GroEL from their preparations, Doig and Trust were able to describe eight other outer membrane antigens of , six of which were shown to be surface exposed. The action of the only monolactam tested, aztreonam, was found to be different, with this antibiotic inducing filamentation in the cells, and this was attributed to the fact that this antibiotic was the only one tested that bound preferentially to a single penicillin-binding protein thought to be essential for helical morphology. The identification and characterization of ultrastructural features of -infected tissue provide valuable insights into the pathogenesis of infection. However, the use of these characteristics to assess clinical outcomes of the infection is limited. Several bacterial toxins, such as toxin or toxin A from , are known to cause alterations in cytoskeletal architecture.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6

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Figures

Image of Figure 1
Figure 1

Morphology of helicobacters. (a) S-shaped H. pylori with five to seven sheathed polar flagella. Field emission SEM, bar = 0.5 µm. (b) Detail of the flagella hook. Negative stain, bar = 0.05 µm. (c) Helical shaped H. felis with periplasmic fibers in pairs and bipolar tufts of sheathed flagella. Field emission SEM, bar marker = 0.5 µm. (d) Detail of periplasmic fibers showing striated appearance. Negative stain, bar = 0.05 µm. (Field emission SEMs courtesy of L. Thompson and negative stains courtesy of S. Danon, School of Microbiology & Immunology, University of New South Wales.)

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Image of Figure 2
Figure 2

Surface structures of . Negative stain of sarcosinate-treated bacteria showing urease as represented by the small donut-like structures (small arrow) and the flagella insertion base (large arrow), bar = 0.1 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Figure 3

Coccoid forms of , (a) Initial ingrowth in the periplasmic space resulting in the formation of U-shaped cells, (b) Conversion to the coccoid form. Ultrathin section, bar = 0.5 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Image of Figure 4
Figure 4

Ultrathin section of colonization of gastric mucus. Bar, 1 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Image of Figure 5
Figure 5

Gastric surfactant of human antral mucosa. Specific jodoplatinate staining of phospholipid-rich structures. Ultrathin section; bar marker represents 0.5 µm. Mg, mucous granules; Lu, lumen.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Figure 6

Intracytoplasmatic vacuoles (V) in gastric epithelial cells induced in vivo by . Ultrathin section. Bar, 0.5 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Figure 7

Ultrastructural appearance of tight junction strands, (a) Normal gastric tissue from a noninfected subject; (b) preparation from an -infected tissue demonstrates a rudimental tight junction complex with reduced number of tight junction strands. Freeze-fracture preparation. Bar, 0.2 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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Figure 8

within the cytoplasm of a neutrophil granulocyte. Ultrathin section. Nu, nucleus, arrows, H. pylori. Bar, 1 µm.

Citation: O'Rourke J, Bode G. 2001. Morphology and Ultrastructure, p 53-67. In Mobley H, Mendz G, Hazell S (ed), . ASM Press, Washington, DC. doi: 10.1128/9781555818005.ch6
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