Porphyromonas gingivalis: Difference between revisions

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{{subpages}}
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{{Taxobox
 
| color = pink
==Classification==
| name =
 
| image =
[[Image: P.gingivalis.jpg|400 px| right]]
| regnum = Eubacteria
 
| phylum = Bacteroidetes
==Higher order taxa==
| classis = Bacteroides
 
| ordo = 
Domain:Bacteria
| familia =
 
| genus = Porphyromonas
Phylum:Bacteroidetes
| species = gingivalis
 
| binomial = ''Porphyromonas gingivalis''
Class:Bacteroides
| binomial_authority =
 
}}
Genus:Porphyromonas gingivalis
[[Image: P.gingivalis.jpg|thumb|400 px| right|Caption here]]
 
===Species===
Genus species:Porphyromonas gingivalis


==Description and significance==
==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. <ref> [http://www.pgingivalis.org/aims.htm | P. gingivalis.org] </ref> 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]] <ref> [http://www.ebi.ac.uk/2can/genomes/bacteria/Porphyromonas_gingivalis.html | Porphyromonas gingivalis] </ref> This bacterium is associated with ''[[Treptonema denticola]]'' and ''[[Bacteroides forsythus]]''
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. <ref> [http://www.pgingivalis.org/aims.htm | P. gingivalis.org] </ref> 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 <ref> [http://www.ebi.ac.uk/2can/genomes/bacteria/Porphyromonas_gingivalis.html | Porphyromonas gingivalis] </ref> This bacterium is associated with Treptonema denticola and Bacteroides forsythus  
<ref> [http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis | Microbe Wiki] </ref>
<ref> [http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis | Microbe Wiki] </ref>


==Genome structure==
==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. <ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis |Microbe Wiki] </ref>
It is found that the size of the genome of ''P. gingivalis'' is 2.34 mega bases. The sequencing of the entire genome is important in order to be able to determine if there are more medical effects of the bacterium besidees periodontal disease.


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. <ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis |Microbe Wiki] </ref>
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 available information to the research community.<ref>[http://www.pgingivalis.org/aims.htm |P.gingivalis.org]</ref>
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.<ref>[http://www.pgingivalis.org/aims.htm |P.gingivalis.org]</ref>


==Cell structure and metabolism==
==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. <ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis  Microbe Wiki]</ref>
{{Image|P.gingivalis 2.jpg|right|350px|Add image caption here.}}
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
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]]. <ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis  Microbe Wiki]</ref>


Ascorbate and aldarate metabolism
''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:


Pyruvate metabolism
Carbohydrate Metabolism


Glyoxylate and dicarboxylate metabolism
Energy 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:'''
Lipid Metabolism
 
Fatty acid biosynthesis


Fatty acid metabolism
Nucleotide Metabolism


Synthesis and degradation of ketone bodies
Amino Acid Metabolism
 
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:'''
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
Metabolism of Complex Carbohydrates


Vitamin B6 metabolism
Metabolism of Complex Lipids


Nicotinate and nicotinamide metabolism
Metabolism of Cofactors and Vitamins
 
Pantothenate and CoA biosynthesis
 
Biotin metabolism
 
Folate biosynthesis
 
One carbon pool by folate
 
Retinol metabolism
 
Porphyrin and chlorophyll metabolism
 
Ubiquinone biosynthesis


==Ecology==
==Ecology==
The organism ''P. gingivalis'' is usually found in the orifice of mammals usually humans. It is associated with ''Treptonema denticola'' and ''Bacteroides forsythus''. There is no valid evidence that the relationship is [[symbiotic]], but is still under researched theory. It contributes to the formation of [[gingivitis]] which is a periodontal disease.


The organism P. gingivalis is usually found in the orifice of mammals usually humans. It is associated with Treptonema denticola and Bacteroides forsythus. There is no valid evidence that the relationship is symbiotic, but is still under researched theory. It contributes to the formation of gingivitis which is a periodontal disease.
==Pathology==
The bacteria, ''P. gingivalis'', in addition to others causes gingivitis as well as periodontis. Gingivitis is "A disorder involving inflammation of the gums; may affect surrounding and supporting structures of the teeth." <ref> [http://www.diseasesdatabase.com/umlsdef.asp?glngUserChoice=34517 | Gingivitis ]</ref> Periodontis is "inflammatory reaction of the tissues surrounding a tooth (periodontium), usually resulting from the extension of gingival inflammation into the periodontium." <ref>[http://www.diseasesdatabase.com/umlsdef.asp?glngUserChoice=29362 | Periodontis]</ref>


==Pathology==
When a gathering of Gram-negative, anaerobic bacteria is observed on the gums, it develops a biofilm called [[plaque]] on the tooth. Such bacteria as ''P. gingivalis'' and ''Actinobacillus actinomycetemcomitans'' are examples. Thus ''P. gingivalis'' expresses [[proteolytic enzymes]] which regulate the protein function in the body <ref>[http://www.nutritionalwellness.com/archives/2006/jul/07_proteolytic.php | Proteolytic Enzymes]</ref> These enzymes are usually utilized for [[Cysteine]] and [[Arginine]] metabolism. However, here they affect the link between the tooth and the bone, thus ultimately separating the two from one another, which causes the taking apart of the tooth from jaw.
The bacteria, P. gingivalis, in addition to others causes gingivitis as well as periodontis. Gingivitis is "A disorder involving inflammation of the gums; may affect surrounding and supporting structures of the teeth." <ref> [http://www.diseasesdatabase.com/umlsdef.asp?glngUserChoice=34517 | Gingivitis ]</ref> Periodontis is "inflammatory reaction of the tissues surrounding a tooth (periodontium), usually resulting from the extension of gingival inflammation into the periodontium." <ref>[http://www.diseasesdatabase.com/umlsdef.asp?glngUserChoice=29362 | Periodontis]</ref> When a gathering of gram-negative, anaerobic bacteria is observed on the gums, it develops a biofilm called plaque on the tooth. Such bacteria as P. gingivalis and Actinobacillus actinomycetemcomitans are examples. Thus P. gingivalis expresses proteolytic enzymes which regulate the protein function in the body <ref>[http://www.nutritionalwellness.com/archives/2006/jul/07_proteolytic.php | Proteolytic Enzymes]</ref>these enzymes that are usually utilized for Cysteine and Arginine metabolism. However, here they affect the link between the tooth and the bone, thus ultimately separating the two from one another, which causes the taking apart of the tooth from jaw.
<ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis | Microbe Wiki]</ref>
<ref>[http://microbewiki.kenyon.edu/index.php/Porphyromonas_gingivalis | Microbe Wiki]</ref>


Line 224: Line 72:


Inflammation of gums
Inflammation of gums
==Application to Biotechnology==
Does this organism produce any useful compounds or enzymes?  What are they and how are they used?


==Current Research==
==Current Research==
1.) <ref> [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 | P.gingivalis & pregnancy ] </ref> León R, Silva N, Ovalle A, Chaparro A, Ahumada A, Gajardo M, Martinez M, Gamonal J. '''"Detection of Porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor"''' ''International Journal of Systematic and Evolutionary Microbiology''. 2007 Jul;78(7):1249-55.
1.) <ref> [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 | P.gingivalis & pregnancy ] </ref> León R, Silva N, Ovalle A, Chaparro A, Ahumada A, Gajardo M, Martinez M, Gamonal J. '''"Detection of Porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor"''' ''International Journal of Systematic and Evolutionary Microbiology''. 2007 Jul;78(7):1249-55.


It has come to the attention of researchers that pregnant women who are expected to have a premature delivery may be caused due to periodontal disease caused by the bacterium P. gingivalis. The notion that bacterial infection causes premature delivery is a common diagnosis. In an experiment with twenty-six women the amniotic sac fluid was gathered as well as sampled of the plaque that resided in the oral cavity on the subgingival layer. After doing many tests on both samples, it was found that indeed the colonies present were that of P. gingivalis. In addition this bacterium was found in the amniotic fluid. As a result of the experiments, of the twenty-six women eight of them had the speculated disease: gingivitis, twelve of them had chronic periodontitis, and the remaining six did not have symptoms of periodontal disease. Thus, women who are pregnant, or are bearing in mind pregnancy, should take care of their “oral health,” making sure that they do not develop such strains of bacteria, to prevent harm to their future offspring.
It has come to the attention of researchers that pregnant women who are expected to have a premature delivery may be caused due to periodontal disease caused by the bacterium ''P. gingivalis''. The notion that bacterial infection causes premature delivery is a common diagnosis. In an experiment with twenty-six women, the [[amniotic sac]] fluid was gathered as well as samples of the plaque that resided in the oral cavity on the subgingival layer. After doing many tests on both samples, it was found that indeed the colonies present were that of ''P. gingivalis''. In addition this bacterium was found in the amniotic fluid. As a result of the experiments, of the twenty-six women showed that eight of them had the speculated disease: gingivitis, twelve of them had chronic periodontitis, and the remaining six did not have symptoms of periodontal disease. Thus, women who are pregnant, or are bearing in mind pregnancy, should take care of their “oral health,” making sure that they do not develop such strains of bacteria, to prevent harm to their future offspring.


2.) <ref> [http://www.sciencedaily.com/releases/2006/05/060529082223.htm | Gum disease & Arteries] </ref>  
2.) American Society for Microbiology. "Genes Discovered That Allow Gum Disease Bacterium To Invade Arteries." ScienceDaily 29 May 2006. 2 April 2008 <ref> [http://www.sciencedaily.com/releases/2006/05/060529082223.htm | Gum disease & Arteries] </ref>  


It has come to the attention of researchers to investigate whether or not gum disease is associated with cardiovascular disease. In an experiment, they took four strains of P. gingivalis and permitted them to contaminate and live inside the artery cells. In a previous experiment Paulo Rodrigues, and his fellow researchers had determined that this bacterium P. gingvalis is able to “invade and survive inside human artery cells.” Thus in this new experiment, after the four strains were developed, they then mutated a gene in each thus seeking to see if with now a “disability” if the bacterium could still “invade and survive” inside the artery cells. After running the tests, it was found that because the strains were now mutated they couldn’t invade as effectively and their survival rate was lessened. This is very important because now we can keep in mind that this pathogenic bacteria is linked with the artery cells, and with further study we may be able to develop “tools” for the averting cardiovascular diseases.
It has come to the attention of researchers to investigate whether or not gum disease is associated with cardiovascular disease. In an experiment, they took four strains of ''P. gingivalis'' and permitted them to contaminate and live inside the artery cells. In a previous experiment Paulo Rodrigues, and his fellow researchers had determined that this bacterium is able to “invade and survive inside human artery cells.” Thus, in this new experiment, after the four strains were developed, they then mutated a gene in each seeking to find a “disability” if the bacterium could still “invade and survive” inside the artery cells. After running the tests, it was found that because the strains were now mutated they couldn’t invade as effectively and their survival rate was lessened. This is very important because now we can keep in mind that this pathogenic bacteria is linked with the artery cells, and with further study we may be able to develop “tools” for the averting cardiovascular diseases.


3.) University at Buffalo (2007, May 9). Molecule That Destroys Bone Also Protects It, New Research Shows. ScienceDaily. Retrieved April 2, 2008, from [http://www.sciencedaily.com­/releases/2007/05/070508200406.htm]


3.) University at Buffalo (2007, May 9). Molecule That Destroys Bone Also Protects It, New Research Shows. ScienceDaily. Retrieved April 2, 2008, from [http://www.sciencedaily.com­/releases/2007/05/070508200406.htm]
In autoimmune disease, a constituent known as IL-17 is accepted to be the main cause of bone destruction and inflammation. It has been learned that in addition to causing [[rheumatoid arthritis]] (RA) this compound IL-17 is also efficient in defensive action against bacteria such as ''P. gingivalis'', and so it helps protect the bones located in the oral cavity. A research experiment was carried out using mice. They use mice lacking the receptors for IL-17 and others used mice with receptors hindered for IL-17; these experiments assumed that the hindered receptors was a therapeutic way for the RA, as well as other diseases such as  [[multiple sclerosis]], [[colitis]], [[psoriasis]] and [[lupus]]. To determine the effects on periodontal disease, the experiment was conducted using the mice lacking the receptors and as a result it was found that these mice were more likely to bone loss, and thus developing the disease. The effects learned were not the ones expected by researchers.  


In autoimmune disease, a constituent known as IL-17 is accepted to be the main cause of bone destruction and inflammation.  It has been learned that in addition to causing rheumatoid arthritis (RA) this compound IL-17 is also efficient in defensive action against bacteria such as P. gingivalis, and so it helps protect the bones located in the oral cavity. A research experiment was carried out using mice. They use mice lacking the receptors for IL-17 and others used mice with receptors hindered for IL-17; these experiments assumed that the hindered receptors was a therapeutic way for the RA, as well as other diseases such as  multiple sclerosis, colitis, psoriasis and lupus. To determine the effects on periodontal disease, the experiment was conducted using the mice lacking the receptors and as a result it was found that these mice were more likely to bone loss, and thus developing the disease. The effects learned were not the ones expected by researchers. In addition, a distinction between periodontal disease and an autoimmune disease should be made. A periodontal disease, is one in which it is considered an infectious disease, here leukocytes, have neutrophils as the major fighters of the infection. The IL-17 component is one of the determining factors of the regulation of neutrophils. Thus if an individual has a deficiency or is lacking the neutrophils it will lose most of its teeth due to the powerful emergence periodontal disease. The benefit of this researched experiment is that now researchers have discovered that there are more than twp types of T helper cells that contribute to the activities of the immune system. This IL-17 component is a type of T-cell “a cytokine, a protein hormone made by "T helper" cells of the immune system that stimulate immunity” which contributes to the autoimmune diseases. More research will be conducted in order to eradicate such autoimmune diseases, which harm their hosts.
A distinction between periodontal disease and an autoimmune disease should be made. A periodontal disease, is one in which it is considered an infectious disease, here leukocytes, have neutrophils as the major fighters of the infection. The IL-17 component is one of the determining factors of the regulation of neutrophils. Thus if an individual has a deficiency or is lacking the neutrophils it will lose most of its teeth due to the powerful emergence periodontal disease. The benefit of this researched experiment is that now researchers have discovered that there are more than twp types of T helper cells that contribute to the activities of the immune system. This IL-17 component is a type of T-cell “a cytokine, a protein hormone made by "T helper" cells of the immune system that stimulate immunity” which contributes to the autoimmune diseases. More research will be conducted in order to eradicate such autoimmune diseases, which harm their hosts.


==References==
==References==
 
{{reflist|2}}
<references/>
 
1. <[http://www.diseasesdatabase.com/umlsdef.asp?glngUserChoice=33653 |Disease Database]>
 
2. <[http://en.wikipedia.org/wiki/Porphyromonas_gingivalis | Wikipedia]>
 
3. ScienceDaily 6 July 2007. 2 April 2008 http://www.sciencedaily.com­/releases/2007/07/070703171912.htm
 
4. [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 León R, Silva N, Ovalle A, Chaparro A, Ahumada A, Gajardo M, Martinez M, Gamonal J. '''"Detection of Porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor"''' ''International Journal of Systematic and Evolutionary Microbiology''. 2007 Jul;78(7):1249-55.]
 
5. Bacterium To Invade Arteries. ScienceDaily. Retrieved April 2, 2008, from http://www.sciencedaily.com/releases/2006/05/060529082223.htm
 
 
 
[Sample reference] [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 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.]

Latest revision as of 01:29, 26 October 2013

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This editable Main Article is under development and subject to a disclaimer.
Scientific classification
Kingdom: Eubacteria
Phylum: Bacteroidetes
Class: Bacteroides
Genus: Porphyromonas
Species: gingivalis
Binomial name
Porphyromonas gingivalis
Caption here

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. [1] 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 [2] This bacterium is associated with Treptonema denticola and Bacteroides forsythus [3]

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. [4] It is found that the size of the genome of P. gingivalis is 2.34 mega bases. The sequencing of the entire genome is important in order to be able to determine if there are more medical effects of the bacterium besidees 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 available information to the research community.[5]

Cell structure and metabolism

Add image caption here.

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. [6]

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

Energy Metabolism

Lipid Metabolism

Nucleotide Metabolism

Amino Acid Metabolism

Metabolism of Other Amino Acids

Metabolism of Complex Carbohydrates

Metabolism of Complex Lipids

Metabolism of Cofactors and Vitamins

Ecology

The organism P. gingivalis is usually found in the orifice of mammals usually humans. It is associated with Treptonema denticola and Bacteroides forsythus. There is no valid evidence that the relationship is symbiotic, but is still under researched theory. It contributes to the formation of gingivitis which is a periodontal disease.

Pathology

The bacteria, P. gingivalis, in addition to others causes gingivitis as well as periodontis. Gingivitis is "A disorder involving inflammation of the gums; may affect surrounding and supporting structures of the teeth." [7] Periodontis is "inflammatory reaction of the tissues surrounding a tooth (periodontium), usually resulting from the extension of gingival inflammation into the periodontium." [8]

When a gathering of Gram-negative, anaerobic bacteria is observed on the gums, it develops a biofilm called plaque on the tooth. Such bacteria as P. gingivalis and Actinobacillus actinomycetemcomitans are examples. Thus P. gingivalis expresses proteolytic enzymes which regulate the protein function in the body [9] These enzymes are usually utilized for Cysteine and Arginine metabolism. However, here they affect the link between the tooth and the bone, thus ultimately separating the two from one another, which causes the taking apart of the tooth from jaw. [10]

Symptoms include:[11]

Swelling, redness, and pain in the gums

Bad Breath

Gums fail to have structure

Inflammation of gums

Current Research

1.) [12] León R, Silva N, Ovalle A, Chaparro A, Ahumada A, Gajardo M, Martinez M, Gamonal J. "Detection of Porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor" International Journal of Systematic and Evolutionary Microbiology. 2007 Jul;78(7):1249-55.

It has come to the attention of researchers that pregnant women who are expected to have a premature delivery may be caused due to periodontal disease caused by the bacterium P. gingivalis. The notion that bacterial infection causes premature delivery is a common diagnosis. In an experiment with twenty-six women, the amniotic sac fluid was gathered as well as samples of the plaque that resided in the oral cavity on the subgingival layer. After doing many tests on both samples, it was found that indeed the colonies present were that of P. gingivalis. In addition this bacterium was found in the amniotic fluid. As a result of the experiments, of the twenty-six women showed that eight of them had the speculated disease: gingivitis, twelve of them had chronic periodontitis, and the remaining six did not have symptoms of periodontal disease. Thus, women who are pregnant, or are bearing in mind pregnancy, should take care of their “oral health,” making sure that they do not develop such strains of bacteria, to prevent harm to their future offspring.

2.) American Society for Microbiology. "Genes Discovered That Allow Gum Disease Bacterium To Invade Arteries." ScienceDaily 29 May 2006. 2 April 2008 [13]

It has come to the attention of researchers to investigate whether or not gum disease is associated with cardiovascular disease. In an experiment, they took four strains of P. gingivalis and permitted them to contaminate and live inside the artery cells. In a previous experiment Paulo Rodrigues, and his fellow researchers had determined that this bacterium is able to “invade and survive inside human artery cells.” Thus, in this new experiment, after the four strains were developed, they then mutated a gene in each seeking to find a “disability” if the bacterium could still “invade and survive” inside the artery cells. After running the tests, it was found that because the strains were now mutated they couldn’t invade as effectively and their survival rate was lessened. This is very important because now we can keep in mind that this pathogenic bacteria is linked with the artery cells, and with further study we may be able to develop “tools” for the averting cardiovascular diseases.

3.) University at Buffalo (2007, May 9). Molecule That Destroys Bone Also Protects It, New Research Shows. ScienceDaily. Retrieved April 2, 2008, from [1]

In autoimmune disease, a constituent known as IL-17 is accepted to be the main cause of bone destruction and inflammation. It has been learned that in addition to causing rheumatoid arthritis (RA) this compound IL-17 is also efficient in defensive action against bacteria such as P. gingivalis, and so it helps protect the bones located in the oral cavity. A research experiment was carried out using mice. They use mice lacking the receptors for IL-17 and others used mice with receptors hindered for IL-17; these experiments assumed that the hindered receptors was a therapeutic way for the RA, as well as other diseases such as multiple sclerosis, colitis, psoriasis and lupus. To determine the effects on periodontal disease, the experiment was conducted using the mice lacking the receptors and as a result it was found that these mice were more likely to bone loss, and thus developing the disease. The effects learned were not the ones expected by researchers.

A distinction between periodontal disease and an autoimmune disease should be made. A periodontal disease, is one in which it is considered an infectious disease, here leukocytes, have neutrophils as the major fighters of the infection. The IL-17 component is one of the determining factors of the regulation of neutrophils. Thus if an individual has a deficiency or is lacking the neutrophils it will lose most of its teeth due to the powerful emergence periodontal disease. The benefit of this researched experiment is that now researchers have discovered that there are more than twp types of T helper cells that contribute to the activities of the immune system. This IL-17 component is a type of T-cell “a cytokine, a protein hormone made by "T helper" cells of the immune system that stimulate immunity” which contributes to the autoimmune diseases. More research will be conducted in order to eradicate such autoimmune diseases, which harm their hosts.

References