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Porphyromonas gingivalis









Porphyromonas gingivalis


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Porphyromonas gingivalis

Scientific classification
Kingdom:
Bacteria
Phylum:
Bacteroidetes
Class:
Bacteroidetes
Order:
Bacteroidales
Family:
Porphyromonadaceae
Genus:
Porphyromonas
Species:
P. gingivalis

Binomial name

Porphyromonas gingivalis
(Coykendall et al. 1980) Shah and Collins 1988


Porphyromonas gingivalis belongs to the phylum Bacteroidetes and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar.


It is found in the oral cavity, where it is implicated in certain forms of periodontal disease,[1] as well as in the upper gastrointestinal tract, the respiratory tract, and the colon. It has also been isolated from women with bacterial vaginosis.[2]Collagen degradation observed in chronic periodontal disease results in part from the collagenase enzymes of this species. It has been shown in an in vitro study that P. gingivalis can invade human gingival fibroblasts and can survive in them in the presence of considerable concentrations of antibiotics.[3]P. gingivalis also invades gingival epithelial cells in high numbers, in which cases both bacteria and epithelial cells survive for extended periods of time. High levels of specific antibodies can be detected in patients harboring P. gingivalis.


In addition, P. gingivalis has been linked to Alzheimer's disease[4] and rheumatoid arthritis. It contains the enzyme peptidyl-arginine deiminase, which is involved in citrullination.[5] Patients with rheumatoid arthritis have an increased incidence of periodontal disease;[6] antibodies against the bacterium are significantly more common in these patients.[7]


P. gingivalis is divided into K-serotypes based upon capsular antigenicity of the various types.[8]




Contents






  • 1 Genome


  • 2 Virulence factors


    • 2.1 Gingipain


    • 2.2 Capsular polysaccharide


    • 2.3 Fimbriae


      • 2.3.1 Long fimbriae


      • 2.3.2 Short fimbriae


      • 2.3.3 Accessory fimbriae




    • 2.4 Evasion of host defenses and immune responses


    • 2.5 Community activist




  • 3 See also


  • 4 References


  • 5 External links





Genome[edit]


The genome of P. gingivalis has been described in 2003 and revealed 1,990 open reading frames (i.e. protein-coding sequences), encoded by 2,343,479 bp, with an average G+C content of 48.3%.[9] An estimated 463 genes are essential.[10]



Virulence factors[edit]



Gingipain[edit]


Arg-gingipain (Rgp) and lys-gingipain (Kgp) are secreted by P. gingivalis. These gingipains serve many functions for the organism, which contributes to its survival and virulence.[11]


Arg-gingipains have been found to play a key role in the collection of nutrients for P. gingivalis survival. Rgp degrades large peptides of the host organism to provide the bacterium with an abundant nitrogen and carbon source from human albumin serum.[12]P. gingivalis can also degrade transferrin within host cells which provides the organism with an abundant iron source needed to perform multiple cellular functions.[13]


The gingipains are also responsible for a number of necessary functions related to host invasion and colonization. Rgp gingipains are necessary for adhesion and invasion as they processed precursor proteins of long fimbriae.[13] The P. gingivalis genes encoding RgpA, Kgp, and hemagglutinin A (HagA) were strongly expressed after incubation with T. denticola. The hemagglutinin adhesion domain-containing proteins act to increase adhesive capacities of P. gingivalis with other bacterial species.[14] They are also associated with coordinating the integrity of the biofilm in the developing and maturation phase.[15] Lys- gingipains (Kgp) can bind to immobilized matrix proteins fibrinogen and fibronectin and may have a role in host colonization.[16]


Gingipains also have the ability to degrade multiple signals of the host immune response. They have the ability to cleave subclass 1 and 3 IgG antibodies[17] as well as proinflammatory cytokines such as IL-1β, IL-2, IL-6, TNF-α and IL-8 in regions of high P. gingivalis concentration.,[18] which impairs host immune response function. Rgp can inhibit IL-2 accumulation in T-cells, which enables it to evade the host adaptive immune response, by modulating T-cell communication and proliferation.[19]


Gingipains are key factors in tissue damage symptoms of periodontitis, which results from the degradation of matrix metalloproteins, collagen, and fibronectin.[13] Degradation of these substrates interferes with interactions between host cells and the extracellular matrix, therefore impeding wound healing and causing destruction of periodontal tissues.[13] Rgp is responsible for eliciting the host inflammatory response via the p38α MAPK transduction pathway. This response likely contributes to the inflammatory nature of periodontitis and is involved in tissue and bone destruction.[12]


Gingipains have been associated with Alzheimer's disease [20]. Gingipains were discovered from TMA's of patients exhibiting alzheimers disease brain pathology. Both RgpB and Kbp were discovered from hippocampus and cerebral cortex of AD patients and were found to be associated with tau load, a marker for AD pathology and ubiquitin, which accumulates in tau tangles and amyloid beta plaques in AD brain. P. gingivalis 16S rRNA was also discovered in the cerebral cortex and csf of AD brains. Pretreatment with gingipain inhibitors protected neuron cell degradation caused by administration of gingipains in murine model.



Capsular polysaccharide[edit]


The encapsulated strain of P. gingivalis is much more virulent than the nonencapsulated strain in a mouse abscess model.[21] The capsule is a capsular polysaccharide and when present down regulates cytokine production especially proinflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α, indicating host evasion responses.[18][21] However, other studies have found the CPS to elicit host immune responses like PMN migration and dose and time dependent expression of cell migration chemokines like MCP-1, KC, MIP-2 and RANTES in CPS-challenged murine peritoneal macrophages. These conditions are likely to contribute to the inflammatory lesions observed in periodontitis.[22]


Vaccines made from P. gingivalis CPS apparently impair oral bone loss in murine models. These vaccines have been able to elicit potent immune responses such as increased IgM and IgG responses that recognize whole P. gingivalis organisms.[23]



Fimbriae[edit]


Fimbriae are appendages involved in cellular attachment and greatly contribute to virulence and are found on many Gram-negative and some Gram-positive bacteria.


P. gingivalis virulence is heavily associated with fimbriae as they have been characterized to be key factors in adhesion, invasion, and colonization. Fimbriae are also responsible for invasion of membrane vesicles into host cells.[13] They were found to bind to cellular α5β1 integrins, which mediated adherence and impaired the homeostatic controls of host cells.[24] Fimbriae were also found to be associated with modulating β2 integrin adhesive activity for uptake by monocytes using the CD14/TLR2/PI3K signaling complex, which may contribute to intracellular evasion tactics by P. gingivalis.[25]P. gingivalis has long fimbriae, short fimbriae, and accessory components, each of which have distinct functions.[15]



Long fimbriae[edit]


Long fimbriae (FimA), also known as major fimbriae, are long, peritrichous, filamentous components.[26] They have a role in initial attachment and organization of biofilms, as they act as adhesins that mediate invasion and colonization of host cells contributing to P. gingivalis virulence.[15]



Short fimbriae[edit]


Short fimbriae (Mfa1), also known as minor fimbriae, have distinct roles from long fimbriae and are characterized to be essential for cell-cell auto aggregation and recruitment for microcolony formation.[26] Short fimbriae are involved in cell-cell adhesion with other dental commensals. It was found to coadhere and develop biofilm in conjunction with Streptococcus gordonii by interaction with SspB streptococcal surface polypeptide.[27] This interaction may be essential in the invasion of dentinal tubules by P. gingivalis.[28]



Accessory fimbriae[edit]


Fim C, D, and E accessory components associate with the main FimA protein and have a role in binding with matrix proteins and interaction with CXC-chemokine receptor 4. Loss of function experiments have confirmed that P. gingivalis mutants deficient for Fim C, D, or E have drastically attenuated virulence.[29]



Evasion of host defenses and immune responses[edit]


P. gingivalis has many ways of evading host immune responses which affects its virulence. It does this by using a combination of gingipain proteases, a capsular polysaccharide, induction of host cell proliferation, and the cleavage of chemokines responsible for neutrophil recruitment.[17][30]


Virulent P. gingivalis further modulates leukocyte recruitment by proteolysis of cytokines and chemokines that are secreted by the host cells. The arg-gingipain and lys-gingipains are responsible for this proteolysis. In a study using a mouse model, P. gingivalis was specifically found to down-regulate IL-8 induction, causing delayed neutrophil recruitment. Prevention of neutrophil recruitment may inhibit the clearance of the bacterium from the site of infection allowing for colonization.[30]P. gingivalis is able to evade opsonophagocytosis from PMN’s by using Gingipain K (Kgp) to cleave IgG 1 and 3. This further modulates immune response by impairing signaling.[17] Other studies have found that P. gingivalis can subvert the complement pathway through C5αR and C3αR, which modulates the killing capacity of leukocytes, allowing for uncontrolled bacterial growth.[30][31][32]P. gingivalis was also found to inhibit pro inflammatory and antimicrobial responses in human monocytes and mouse macrophages by fimbrial binding to CXCR4, inducing PKA signaling and inhibiting TLR-2-mediated immune response.[33]


Once in the host cells, P. gingivalis is capable of inhibiting apoptosis by modulating the JAK/Stat pathway that controls mitochondrial apoptotic pathways.[34][15] A proliferative phenotype maybe beneficial to the bacterium as it provides nutrients, impairs host cell signaling, and compromises the integrity of the epithelial cell layer, allowing for invasion and colonization.[15]



Community activist[edit]


P. gingivalis is a "red" bacterium and a "keystone" bacterium in the onset of chronic adult periodontitis.[35] Though it is found in low abundance in the oral cavity, it causes a microbial shift of the oral cavity, allowing for uncontrolled growth of the commensal microbial community. This leads to periodontitis through the disruption of the host tissue homeostasis and adaptive immune response.[36] After using laser capture microdissection plus qRT-PCR to detect P. gingivalis in human biopsies, colocalization of P. gingivalis with CD4+ T cells was observed.[37] However, the infection mechanism of T cells by P. gingivalis remains unknown.


P. gingivalis has been associated with increasing the virulence of other commensal bacteria in both in vivo and in vitro experiments. P. gingivalis outer membrane vesicles were found to be necessary for the invasion of epithelial cells of Tannerella forsythia.[38]P. gingivalis short fimbriae were found to be necessary for coculture biofilm formation with Streptococcus gordonii.[27] Interproximal and horizontal alveolar bone loss in mouse models are seen in coinfections involving P. gingivalis and Treponema denticola.[39] The role of P. gingivalis as a community activist in periodontitis is seen in specific pathogen-free mouse models of periodontal infections. In these models, P. gingivalis inoculation causes significant bone loss, which is a significant characteristic of the disease. In contrast, germ free mice inoculated with a P. gingivalis monoinfection incur no bone loss, indicating that P. gingivalis alone cannot induce periodontitis.[30]



See also[edit]


  • List of bacterial vaginosis microbiota


References[edit]





  1. ^ Naito M, Hirakawa H, Yamashita A, et al. (August 2008). "Determination of the Genome Sequence of Porphyromonas gingivalis Strain ATCC 33277 and Genomic Comparison with Strain W83 Revealed Extensive Genome Rearrangements in P. gingivalis". DNA Res. 15 (4): 215–25. doi:10.1093/dnares/dsn013. PMC 2575886. PMID 18524787..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"""""""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}


  2. ^ Africa, Charlene; Nel, Janske; Stemmet, Megan (2014). "Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation". International Journal of Environmental Research and Public Health. 11 (7): 6979–7000. doi:10.3390/ijerph110706979. ISSN 1660-4601. PMC 4113856. PMID 25014248.


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  4. ^ Potempa, Jan; Dragunow, Mike; Curtis, Maurice A.; Faull, Richard L. M.; Reynolds, Eric C.; Walker, Glenn D.; Hasturk, Hatice; Adamowicz, Karina; Hellvard, Annelie (2019-01-01). "Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small-molecule inhibitors". Science Advances. 5 (1): eaau3333. doi:10.1126/sciadv.aau3333. ISSN 2375-2548. PMC 6357742. PMID 30746447.


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  8. ^ American Academy of Periodontology 2010 In-Service Exam, question A-85


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  16. ^ McAlister, A.D.; Sroka, A; Fitzpatrick, R. E; Quinsey, N.S; Travis, J.; Potempa, J; Pike, R.N (2009). "Gingipain enzymes from Porphyromonas gingivalis preferentially bind immobilized extracellular proteins: a mechanism favouring colonization?". J. Periodontal Res. 44 (3): 348–53. doi:10.1111/j.1600-0765.2008.01128.x. PMC 2718433. PMID 18973544.


  17. ^ abc Vincents, Bjarne; Guentsch, Arndt; Kostolowska, Dominika; von Pawel-Rammingen, Ulrich; Eick, Sigrun; Potempa, Jan; Abrahamson, Magnus (October 2011). "Cleavage of IgG1 and IgG3 by gingipain K from Porphyromonas gingivalis may compromise host defense in progressive periodontitis". FASEB Journal. 25 (10): 3741–3750. doi:10.1096/fj.11-187799. PMC 3177567. PMID 21768393.


  18. ^ ab Grenier, D; Tanabe, S (2010). "Porphyromonas gingivalis Gingipains Trigger a Proinflammatory Response in Human Monocyte-derived Macrophages Through the p38alpha Mitogen-activated Protein Kinase Signal Transduction Pathway". Toxins (Basel). 2 (3): 341–52. doi:10.3390/toxins2030341. PMC 3153194. PMID 22069588.


  19. ^ Khalaf, Hazem; Bengtsson, Torbjörn (2012). Das, Gobardhan, ed. "Altered T-Cell Responses by the Periodontal Pathogen Porphyromonas gingivalis". PLOS One. 7 (9): 45192. Bibcode:2012PLoSO...745192K. doi:10.1371/journal.pone.0045192. PMC 3440346. PMID 22984628.


  20. ^ Potempa, Jan; Dragunow, Mike; Curtis, Maurice A.; Faull, Richard L. M.; Reynolds, Eric C.; Walker, Glenn D.; Hasturk, Hatice; Adamowicz, Karina; Hellvard, Annelie (2019-01-01). "Porphyromonas gingivalis in Alzheimer's disease brains: Evidence for disease causation and treatment with small-molecule inhibitors". Science Advances. 5 (1): eaau3333. doi:10.1126/sciadv.aau3333. ISSN 2375-2548.


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  24. ^ Tsuda, K; Amano, A; et al. (2005). "Molecular dissection of internalization of Porphyromonas gingivalis by cells using fluorescent beads coated with bacterial membrane vesicle". Cell Struct Funct. 30 (2): 81–91. doi:10.1247/csf.30.81. PMID 16428861.


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  34. ^ Mao, S; Park, Y.; et al. (2007). "Intrinsic apoptotic pathways of gingival epithelial cells modulated by Porphyromonas gingivalis". Cell Microbiol. 9 (8): 1997–2007. doi:10.1111/j.1462-5822.2007.00931.x. PMC 2886729. PMID 17419719.


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  39. ^ Verma RK, Rajapakse S, Meka A, Hamrick C, Pola S, Bhattacharyya I, Nair M, Wallet SM, Aukhil I, Kesavalu L (2010). "Porphyromonas gingivalis and Treponema denticola Mixed Microbial Infection in a Rat Model of Periodontal Disease". Interdiscip Perspect Infect Dis. 2010: 1–10. doi:10.1155/2010/605125. PMC 2879544. PMID 20592756.




External links[edit]


  • Type strain of Porphyromonas gingivalis at BacDive - the Bacterial Diversity Metadatabase

















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Florida Star v. B. J. F.

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Florida Star v. B. J. F. From Wikipedia, the free encyclopedia Jump to navigation Jump to search United States Supreme Court case Florida Star v. B. J. F. Supreme Court of the United States Argued March 21, 1989 Decided June 21, 1989 Full case name The Florida Star v. B. J. F. Citations 491 U.S. 524 ( more ) 109 S. Ct. 2603; 105 L. Ed. 2d 443; 1989 U.S. LEXIS 3120; 57 U.S.L.W. 4816; 16 Media L. Rep. 1801 Prior history The Florida Star v. B.J.F., 530 So.2d 286 (1988) Supreme Court of Florida; Florida Star v. B.J.F., 499 So.2d 883 (1986) Fla. Dist. Court of Appeals Holding Florida Stat. § 794.03 is unconstitutional to the extent it makes the truthful reporting of information that was a matter of public record unlawful, as it violates the First Amendment. Court membership Chief Justice William Rehnquist Associate Justices William J. Brennan Jr.  · Byron White Thurgood Marshall  · Harry Blac
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Danny Elfman

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Danny Elfman From Wikipedia, the free encyclopedia Jump to navigation Jump to search Danny Elfman Elfman at the 2010 San Diego Comic-Con Born Daniel Robert Elfman ( 1953-05-29 ) May 29, 1953 (age 65) Los Angeles, California, U.S. Spouse(s) Bridget Fonda ( m.  2003) Children 1 Musical career Genres Rock [1] ska [2] new wave film music video game music Occupation(s) Composer, singer, songwriter, record producer Instruments Trombone guitar percussion vocals keyboards [3] Years active 1972–present Associated acts Oingo Boingo James Newton Howard Daniel Robert Elfman (born May 29, 1953) is an American composer, singer, songwriter, and record producer. Elfman first became known for being the lead singer and songwriter for the band Oingo Boingo from 1974 to 1995. He is well known for scoring films and television shows, particularly his frequent collabora
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Retrieve a Users Dashboard in Tumblr with R and TumblR. Oauth Issues

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.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ height:90px;width:728px;box-sizing:border-box; } 0 I am trying to use the TumblR package in R to set up the Oauth Authentication to Retrieve a user's dashboard using the second example in tumblR documentation However I get the following error, it seems that using twitter others have been able to use a different function to get around this, but I am not finding the same function available for Tumblr. See twitter package for R authentication: error 401 My code consumer_key <- OKey consumer_secret <- SKey appname <- App_name tokenURL <- 'http://www.tumblr.com/oauth/request_token' accessTokenURL <- 'http://www.tumblr.com/oauth/acces_token'
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