Porphyromonas gingivalis

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Classification

Higher order taxa

Domain:Bacteria

Phylum:Bacteroidetes

Class:Bacteroides

Genus:Porphyromonas gingivalis

Species

File:.jpg Genus species:Porphyromonas gingivalis

Description and significance

Porphyromonas gingivalis is an anaerobic, gram negative bacterium that can be found within the mouth of an individual. It is observed to be non-motile and rod-shaped. This bacterium is the principal source of periodontal disease. It has been found that in addition to causing human infections, this bacterium also causes much of the antibiotic resistance problems found today. (http://www.pgingivalis.org/aims.htm). The way which it operates is very unique, since it is a gram negative bacteria, it can attach to the subgingival coating of the tooth, and it will substitute the gram positive bacteria that is originally there with its own thus causing an inflammation which will disengage the gums from the teeth. When colonized on blood agar it forms black spots. It is important to sequence the genome of this organism because it is found in many locations within the body not only in the oral cavity also in the gastrointestinal tract, respiratory tract and in the colon, this has many consequences. It has been ascertain that periodontal disease is associated with cardiovascular diseases. This bacterium is associated with Treptonema denticola and Bacteroides forsythus (http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis)

Genome structure

The genome of p. gingivalis is circular and its origin of replication is located at oriC which is juxtaposed by the genes dnaA and PG1949. The guanine and cytosine nucleotides make up approximately 49%. At the present, 2,015 genes have been acknowledged with a total of 23,43,479 nucleotides. It has been found that the genome of p. gingivalis is similar to that of Bacteroides thetaiotaomicron, and B.fragilis within the Cytophaga-Flavobacteria-Bacteroides genome. In addition, it closely resembles the genomes of Chlorobium tepidum, and thus this demonstrates the notion that the phyla of Chlorobia and Cytophaga-Flavobacteria-Bacteroides are associated with one another. It has been discovered using genome analysis that this bacterium can metabolize a range of amino acids which will form different metabolic end products that are lethal to the host which is usually human, as well as harming the host’s gingival tissues, thus causing the expansion of periodontal disease. (http://www.ebi.ac.uk/2can/genomes/bacteria/Porphyromonas_gingivalis.html) It is found that the size of the genome of P. gingivalis is 2.34 mega bases. In addition, the sequencing of the entire genome is important to be able to determine if there are more medical effects of the bacterium in addition to periodontal disease. Researchers want to be able to establish mechanisms for the virulence as well as vaccines. The goals of this project include, the DNA sequence for the genome; analyzing and interpreting the sequence for the W83 strain; integrate the information that was obtained by the interpreted sequences and compare it with the experimental data from the P. gingivalis research community; finally the purpose of the genome sequences is to be able to make clones, reagents, and information to the research community available. (http://www.pgingivalis.org/aims.htm)

Cell structure and metabolism

The P.gingivalis is a gram-negative, non-motile, rod-shaped, anaerobic organism. To function, it undergoes a mechanism in which it binds to the subgingival layer of the mouth using fimbriae. These fimbriae not only aid in the role of adhesion but are also found to be pathogenic to the immune system. (http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis) P. gingivalis takes part in Iron Transport, the way it does this is by using a hemin as a device to help it transport iron. When this builds up it results in the black pigmentation that is detected. To bring the hemin iron complex into the cell it uses an ABC Transporter.

In regards to the metabolism P. gingivalis, it can undergo many different types such as: 

Carbohydrate Metabolism: Glycolysis / Gluconeogenesis Citrate cycle (TCA cycle) Pentose phosphate cycle Pentose and glucuronate interconversions Fructose and mannose metabolism Galactose metabolism Ascorbate and aldarate metabolism Pyruvate metabolism Glyoxylate and dicarboxylate metabolism Propanoate metabolism Butanoate metabolism C5-Branched dibasic acid metabolism

Energy Metabolism:

Oxidative phosphorylation ATP synthase Methane metabolism Carbon fixation Reductive carboxylate cycle (CO2 fixation) Nitrogen metabolism Sulfur metabolism

Lipid Metabolism:

Fatty acid biosynthesis Fatty acid metabolism Synthesis and degradation of ketone bodies Sterol biosynthesis Bile acid biosynthesis C21-Steroid hormone metabolism Androgen and estrogen metabolism

Nucleotide Metabolism:

Purine metabolism Pyrimidine metabolism Nucleotide sugars metabolism

Amino Acid Metabolism:

Glutamate metabolism Alanine and aspartate metabolism Glycine, serine and threonine metabolism Methionine metabolism Cysteine metabolism Valine, leucine and isoleucine degradation Valine, leucine and isoleucine biosynthesis Lysine biosynthesis Lysine degradation Arginine and proline metabolism Histidine metabolism Tyrosine metabolism Phenylalanine metabolism Tryptophan metabolism Phenylalanine, tyrosine and tryptophan biosynthesis Urea cycle and metabolism of amino groups

Metabolism of Other Amino Acids:

beta-Alanine metabolism Taurine and hypotaurine metabolism Aminophosphonate metabolism Selenoamino acid metabolism Cyanoamino acid metabolism D-Glutamine and D-glutamate metabolism D-Arginine and D-ornithine metabolism D-Alanine metabolism Glutathione metabolism

Metabolism of Complex Carbohydrates: Starch and sucrose metabolism Biosynthesis and degradation of glycoprotein Aminosugars metabolism Lipopolysaccharide biosynthesis Peptideglycan biosynthesis Glycosaminoglycan degradation

Metabolism of Complex Lipids: Glycerolipid metabolism Inositol phosphate metabolism Sphingophospholipid biosynthesis Phospholipid degradation Sphingoglycolipid metabolism Prostaglandin and leukotriene metabolism

Metabolism of Cofactors and Vitamins:

Thiamine metabolism Riboflavin metabolism Vitamin B6 metabolism Nicotinate and nicotinamide metabolism Pantothenate and CoA biosynthesis Biotin metabolism Folate biosynthesis One carbon pool by folate Retinol metabolism Porphyrin and chlorophyll metabolism Ubiquinone biosynthesis

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

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Current Research

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References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.