Giant Bacteria


For almost all bacteria it is convenient to be very small, but a few highly specialist groups of bacteria have evolved to be orders of magnitude larger than ordinary bacteria.

Keywords: spirochaetes; epulopiscium; cyanobacteria; sulfur bacteria

Figure 1.

A bundle of Thioploca filaments from marine sediments close to the Peruvian coast. The bundle is placed next to a ruler of 5 cm in length. The Thioploca filaments appear white due to internal sulfur granules that reflect the light.

Figure 2.

Large intestinal symbionts of surgeonfish. These panels, all shown at the same magnification, illustrate the morphological diversity of ‘Epulopiscium’ and its relatives. The cell on the left is the second largest morphotype, Epulopiscium type B. Visible are two large internal offspring cells. Other rod‐shaped and filamentous forms are shown. Scale bar represents 20 μm. Angert, ER (2006) The enigmatic cytoarchitecture of Epulopiscium spp., Microbiology Monographs, Complex Intracellular Structures in Prokaryotes, vol. 2 p. 288. Berlin Heidelberg, Germany: Springer‐Verlag. Reproduced with kind permission of Springer Science and Business Media.

Figure 3.

Examples of large‐celled cyanobacteria. All scale bars are 10 μm. (a) Chroococcus sp., dividing (left) and recently divided cells from this typically freshwater genus. (b) Porphirosiphon notarissi, a filamentous cyanobacterium allied to the large Oscillatoria, isolated from a soil crust in the Namibian desert, displaying the typical disc‐shaped cells in two separate trichomes, enclosed in a common extracellular sheath. Note the apoptotic, vestigial cell between the two trichomes that served to separate them in a process of self immolation. (c) Detail of a morphologically complex Stigonema spp. displaying a main filament consisting of two series of cells, and an incipient uniseriate branch.

Figure 4.

The morphology of the giant sulfur bacteria as they appear in the light microscope: (a) Beggiatoa, (b) Thioploca, (c) Thiothrix, (d) Thiomargarita, (e) Thiovulum, (f) Achromatium. In a–e numerous sulfur inclusions can be seen. Achromatium (f) is the only known bacterium with calcite inclusions. The much larger calcite inclusions conceal the sulfur inclusions, which are also present. The scale bars show typical sizes for each genus. Nevertheless, the cell diameters of sulfur bacteria are highly variable.


Further Reading

Angert ER, Clements KD and Pace NR (1993) The largest bacterium. Nature 362: 239–241.

Fenchel T and Glud RN (1998) Veil architecture in a sulphide‐oxidizing bacterium enhances countercurrent flux. Nature 394: 367–369.

Fossing H, Gallardo VA, Jørgensen BB et al. (1995) Concentration and transport of nitrate by the mat‐forming sulphur bacterium Thioploca. Nature 374: 713–715.

Garcia‐Pichel F (1989) Rapid bacterial swimming measured in swarming cells of Thiovulum majus. Journal of Bacteriology 171: 3560–3563.

Garcia‐Pichel F (2000) Cyanobacteria. In: Lederberg J (ed.) Encyclopedia of Microbiology, 2nd edn. San Diego, CA: Academic Press.

Jørgensen BB and Gallardo VA (1999) Thioploca spp.: filamentous sulfur bacteria with nitrate vacuoles. FEMS Microbiology Ecology 28: 301–313.

Leadbetter JR, Schmidt TM, Graber JR and Breznak JA (1999) Acetogenesis from H2 plus CO2 by spirochaetes from termite guts. Science 283: 686–689.

Lilburn TG, Kim KS, Ostrom NE et al. (2001) Nitrogen fixation by symbiotic and free‐living spirochaetes. Science 292: 2495–2498.

Schulz HN, Brinkhoff T, Ferdelman TG et al. (1999) Dense populations of a giant sulfur bacterium in Namibian shelf sediments. Science 284: 493–495.

Teske A and Nelson DC (2004) The genera Beggiatoa and Thioploca. In: Dworkin M, Falkow S, Rosenberg E, Schleifer K‐H and Stakebrandt E (eds.) The Prokaryotes: An Evolving Electronic Resource for the Microbiological Community. New York: Springer.

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How to Cite close
Schulz‐Vogt, Heide N, Angert, Esther R, and Garcia‐Pichel, Ferran(Sep 2007) Giant Bacteria. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0020371]