Bacterial Cells

Abstract

Bacteria are prokaryotes and therefore have a simple cell structure. There is no nucleus and genetic material is free within the cytoplasm. The two fundamental types of bacteria – Gram‐positive and Gram‐negative – have different cell wall structures.

Keywords: bacteria; bacterial structures; bacterial envelope; plasma membrane; cell wall; cytoplasm; cytoplasmic granules; flagella; Gram stain

Figure 1.

(a) Photograph of a piece of the gunflint chert from the northern shore of Lake Superior, Ontario, Canada. The rock measures about 20 cm along the long axis and the wavey striations of the layers of an ancient ∼3000 million‐year‐old stromatolite can be seen in the middle of the rock. (b) Bright‐field light micrograph of a thin section of the gunflint chert showing the mineralized remains of prokaryotic cells. (c) Light micrograph using phase optics of a living modern‐day biofilm from a stream in southern Ontario for comparison with (b). These figures were originally supplied by F.G. Ferris, University of Toronto and are reprinted from Beveridge (1988) with permission of the Canadian Journal of Microbiology. Copyright © 1988 NRC Research Press.

Figure 2.

Electron micrograph of a thin section of Leptothrix discophera which shows many structural attributes of a bacterial cell. This is a Gram‐negative cell and the inner bilayer of the cell envelope is called the plasma membrane which encloses the cytoplasm. Reprinted from Beveridge (1988) with permission of the Canadian Journal of Microbiology. Copyright © 1988 NRC Research Press.

Figure 3.

Thin section of a magnetotactic spirillum (a Gram‐negative bacterium) which contains a chain of magnetosomes containing small particles of magnetite (Fe3O4). This sample was supplied by D. Bazylinski, University of Iowa.

Figure 4.

(a) Thin section of the cyanobacterium Synechococcus GL‐24 showing the concentric arrangement of the photosynthetic membranes and the carboxysomes. (b) Thin section of a Chlorobium sp. which is a green sulfur bacterium showing the photosynthetic chlorosomes. Both (a) and (b) were provided by S. Douglas, University of Guelph and reprinted from Schultze‐Lam S et al. (1992) Journal of Bacteriology174: 7971–7981, with permission from the American Society for Microbiology.

Figure 5.

Electron micrograph of a negatively stained Caulobacter sp. showing its unusual shape complete with stalk and holdfast. Reprinted from Beveridge (1988) with permission of the Canadian Journal of Microbiology. Copyright © 1988 NRC Research Press.

Figure 6.

Negative stain of the proximal end of a flagellum from Campylobacter fetus subsp. fetus which shows the filament, hook and basal body (L, P and S‐M rings).

Figure 7.

Thin section of a Bacillus megaterium endospore.

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Further Reading

Beveridge TJ (1981) Ultrastructure, chemistry and function of the bacterial cell wall. International Review of Cytology 72: 229–317.

Beveridge TJ (1988) The bacterial surface: general considerations towards design and function. Canadian Journal of Microbiology 34: 363–372.

Beveridge TJ (1989) The structure of bacteria. In: Poindexter JS and Leadbetter ER (eds) Bacteria in Nature: A Treatise on the Interaction of Bacteria and their Habitats, pp. 1–65. New York: Plenum Publishing.

Beveridge TJ (1990) Mechanism of Gram variability in select bacteria. Journal of Bacteriology 172: 1609–1620.

Beveridge TJ (1994) Bacterial S‐layers. Current Opinion in Structural Biology 4: 204–212.

Beveridge TJ and Davies JA (1983) Cellular response of Bacillus subtilis and Escherichia coli to the Gram stain. Journal of Bacteriology 156: 846–858.

Beveridge TJ and Graham LL (1991) Surface layers of bacteria. Microbiological Reviews 55: 684–705.

Beveridge TJ and Schultze‐Lam S (1997) The response of selected members of the Archaea to the Gram stain. Microbiology 142: 2887–2895.

Beveridge TJ, Makin SA, Kadurugamuwa JL and Li Z (1997) Interactions between biofilms and the environment. FEMS Microbiology Reviews 20: 291–303.

Costerton JW, Cheng K‐J, Geesey GG et al. (1987) Bacterial biofilms in nature and disease. Annual Reviews of Microbiology 41: 435–464.

Davies JA, Anderson GK, Beveridge TJ and Clark HC (1983) Chemical mechanisms of the Gram stain and synthesis of a new electron‐opaque marker for electron microscopy which replaces the iodine mordant of the stain. Journal of Bacteriology 156: 837–845.

Koch AL (1995) Bacterial Growth and Form. New York: Chapman and Hall.

König H and Messner P (special eds) (1997) 4th International S‐layer Workshop (Rothenburg o.d. Tauber, Germany). FEMS Microbiology Reviews 20: 5–175.

Macnab RM and DeRosier DJ (1988) Bacterial flagellar structure and function. Canadian Journal of Microbiology 34: 442–451.

Messner P and Sleytr UB (1992) Crystalline bacterial cell surface layers. Advances in Microbial Physiology 33: 213–275.

Poindexter JS and Leadbetter ER (eds) (1989) Bacteria in Nature: A Treatise on the Interaction of Bacteria and their Habitats, vol. 3. New York: Plenum Publishing.

Salton MRJ (1963) The relationship between the nature of the cell wall and the Gram stain. Journal of General Microbiology 30: 223–235.

Walter MR (1983) Archean stromatolites: evidence of the earth's earliest benthos. In: Schopf JW (ed.) Earth's Earliest Biosphere: Its Origin and Evolution, pp. 187–213. Princeton: Princeton University Press.

Whitfield CW (1993) Biosynthesis and expression of cell‐surface polysaccharides in Gram‐negative bacteria. Advances in Microbial Physiology 35: 135–246.

Wilson DR and Beveridge TJ (1993) Bacterial flagellar filaments and their component flagellins. Canadian Journal of Microbiology 39: 415–427.

Woese CR, Kandler O and Wheelis ML (1990) Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya. Proceedings of the National Academy of Sciences of the USA 87: 4576–4579.

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How to Cite close
Beveridge, Terry J(Dec 2001) Bacterial Cells. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0000296]