Fusobacterium nucleatum
A Microbial Biorealm page on the genus Fusobacterium nucleatum
Classification
Higher order taxa
root; cellular organisms; Bacteria; Fusobacteria; Fusobacteria (class); Fusobacteriaceae; Fusobacterales; Fusobacterium
Genus
Fusobacterium
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NCBI: Taxonomy |
Description and significance
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
Fusobacterium nucleatum is a bacterium that is commonly found in the dental plaque of humans and is frequently associated with gum disease. The cells of F. nucleatum are fusiform rods or spindle-shaped of many different lengths. In fact, the name refers to the organism as a small spindle-shaped rod. F. nucleatum is found in the dental plaque of many primates, thus includes man. This bacteria has been experimented to play a central role in dental plaque formation. This is due to its ability to adhere to a wide range of both Gram-positive and Gram-negative plaque microorganisms, such as Porphyromonas gingivalis. F. nucleatum is very much associated with periodontitis, along with invasive human infections of the head and neck, chest, lung, liver and abdomen. Due to its adherence ability, it can be associated with viruses, which adhere to host tissue cells as an invasion and modulate the host's immune response.
The pathogenic potential of Fusobacterium nucleatum and its significance in the development of periodontal diseases, as well as in infections in other organs, have gained new interest for several reasons. First, this bacterium has a very high chance to be pathogenic because of its high frequency in periodontal lesions, its production of irritants that affect the tissue, its ability to share synergisms with other bacteria in mixed infections, and its ability to form numerous aggregates with other suspected pathogens in periodontal disease(therefore, it acts as a bridge between early and late colonizers on surfaces of teeth). Second, F. nucleatum is the most common in clinical infections of other body sites. Third, recent new techniques have made it possible to obtain more information about F. nucleatum on the genetic level, thereby also gaining better knowledge of the structure and functions of the outer membrane proteins, which are of great interest with respect to coaggregation, cell nutrition, and antibiotic susceptibility.
Fusobacterium nucleatum ATCC23726 is one type of Fusobacterium nucleatum that is still having its full assembly in progress.
Genome structure
Fusobacterium nucleatum is a Gram negative bacterium that does not create spores and is not motile. This bacterium has a G-C content of about 27 to 28 mol%. Its genome size is about 2.4 x 10^6 base pairs (bp). All in all, colony morphology is not a consistent parameter of F. nucleatum. Therefore, it is not sufficient for species identification.
Overall, this bacterium is an anaerobic creature that grows in an environment with only up to 6% oxygen saturation. This organism’s ability to produce butyric acid as a major product of fermentation of glucose and peptone is what differentiates Fusobacterium species from other gram-negative, non-sporing rod-shaped bacterium.
Through phylogenetic grouping through analysis of the 16s rRNA sequences, F. nucleatum was found to be closely related to Bacteroides and the flavobacteria. Similarities have been found with F. nucleatum and the other two species with regards to its DNA and its antigenic composition. In addition, F. nucleatum is found to exhibit high levels of homology with F. alocis, F. periodonticum, and F. simiae. All these organisms, along with F. nucleatum, colonize in oral cavities.
Native plasmids have been identified in strains of F. nucleatum. Using one of the native plasmid pFN1, a F. nucleatum - E. coli shuttle vector has been developed.
Cell structure and metabolism
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Ecology
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Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
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References
Edited by Jason Homan, student of Rachel Larsen and Kit Pogliano
