Actinomyces naeslundii: Difference between revisions

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==Description and significance==
==Description and significance==
''Actinomyces naeslundii'' is a gram-positive, rod-shaped, facultative anaerobe found in the oral cavity of humans and other animals.  This non-motile bacillus is one of only a few gram-positive bacteria characterized as having fimbriae (Wu et al., 2001).  The type 1 fimbriae of ''A. naeslundii'' mediate adhesion of this organism to the tooth surface (Chen et al., 2007).  This microorganism is mesophilic and grows in temperatures ranging from 15°C to 40°C with an optimum growing temperature of 37°C, the normal human body temperature. ''Actinomyces naeslundii'' is commonly found in large numbers in the oral cavity and is a major component of dental plaque.  It has also been linked to dental root caries, periodontal disease and even a few non-oral infections.  
''Actinomyces naeslundii'' is a gram-positive, rod-shaped, non-spore-forming, non-acid-fast, facultative anaerobe found in the oral cavity of humans and other animals.  This non-motile bacillus is one of only a few gram-positive bacteria characterized as having fimbriae (Wu et al., 2001).  The type 1 fimbriae of ''A. naeslundii'' mediate adhesion of this organism to the tooth surface (Chen et al., 2007).  This microorganism is mesophilic and grows in temperatures ranging from 15°C to 40°C with an optimum growing temperature of 37°C, the normal human body temperature. ''Actinomyces naeslundii'' is commonly found in large numbers in the oral cavity and is a major component of dental plaque.  It has also been linked to dental root caries, periodontal disease and even opportunistic infections such as actinomycosis.
 
Actinomycosis is a chronic bacterial infection caused by certain ''Actinomyces'' bacterium such as ''A. naeslundii'', ''A. viscosus'', ''A. odontolyticus'' and ''A. bovis''.  All the species are normal inhabitants of the human oral cavity except for ''A. bovis''.
 


==Genome structure==
==Genome structure==

Revision as of 16:50, 5 May 2008

A Microbial Biorealm page on the genus Actinomyces naeslundii

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Classification

Higher order taxa

Bacteria; Actinobacteria; Actinobacteridae; Actinomycetales; Actinomycetaceae

Species

Actinomyces naeslundii (NCBI: Taxonomy)

Description and significance

Actinomyces naeslundii is a gram-positive, rod-shaped, non-spore-forming, non-acid-fast, facultative anaerobe found in the oral cavity of humans and other animals. This non-motile bacillus is one of only a few gram-positive bacteria characterized as having fimbriae (Wu et al., 2001). The type 1 fimbriae of A. naeslundii mediate adhesion of this organism to the tooth surface (Chen et al., 2007). This microorganism is mesophilic and grows in temperatures ranging from 15°C to 40°C with an optimum growing temperature of 37°C, the normal human body temperature. Actinomyces naeslundii is commonly found in large numbers in the oral cavity and is a major component of dental plaque. It has also been linked to dental root caries, periodontal disease and even opportunistic infections such as actinomycosis.

Actinomycosis is a chronic bacterial infection caused by certain Actinomyces bacterium such as A. naeslundii, A. viscosus, A. odontolyticus and A. bovis. All the species are normal inhabitants of the human oral cavity except for A. bovis.


Genome structure

The genome of Actinomyces naeslundii strain MG1 has 3,042,856 base pairs. It has a GC content of 68.5% with the number of G+C bases at 2,083,309 base pairs (CMR). Additionally, 87.6% of the genome are known to be coding sequences. There are 2761 protein coding genes and those make up 97.9% of the total genes (CMR). Transfer RNA genes account for only 1.8% of the total genes, while the percentage of ribosomal RNA genes is even smaller at 0.3% (CMR).

Cell structure and metabolism

Interesting features of cell structure; how it gains energy; what important molecules it produces.


Ecology

Habitat; symbiosis; contributions to environment.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

References

Comprehensive Microbial Resource (CMR). (2006). Actinomyces naeslundii MG1 Genome Page. The Institute of Genomic Research (TIGR), a division of J. Craig Venter Institute (JCVI). Retrieved May 1, 2008 from <http://cmr.tigr.org/tigr-scripts/CMR/GenomePage.cgi?org=gan>.

H. Wu and P.M. Fives-Taylor. "Molecular strategies for fimbrial expression and assembly." Critical Reviews in Oralal Biology & Medicine. 2001. Volume 12. p. 101–115.

P. Chen, J. O. Cisar, S. Hess, J. T. C. Ho, and K. P. Leung. "Amended Description of the Genes for Synthesis of Actinomyces naeslundii T14V Type 1 Fimbriae and Associated Adhesin." Infection and Immunity. 2007. Volume 75(No. 8). p. 4181 - 4185.