User:S4400077: Difference between revisions

Revision as of 12:03, 21 September 2016

Jolene Sim

Bench E

31 August 2016 ^[1]

Classification

Higher order taxa

Bacteria – Bacteria – Bacteroidetes – Bacteroidia – Bacteroidales – Porphyromonadaceae – Porphyromonas ¹

Species

Species name: Porphyromonas gingivalis

Type strain: W38 2 (consult LPSN http://www.bacterio.net/index.html for this information)

Description and significance

Porphyromonas gingivalis (P. gingivalis) is a non-motile, asaccharolytic, rod-shaped gram negative bacteria. 3 It is obligately anaerobic which requires iron for growth and forms black-pigmented colonies on blood agar plates. 3 P.gingivalis is significant in pathogenesis and progression of inflammations in periodontal diseases. 3 It is detected in 85.7% of subgingival plaque samples from chronic periodontal patients. 3 The disease initially occurs as acute inflammation of gingival tissue, and untreated infections progressively cause formation of teeth pockets and loss of teeth. 3 Habitat of P. gingivalis is subgingival sulcus of human oral cavity, and serves as secondary colonizer of dental plaques by attaching onto parimary colonizers such as Streptococcus gordonii and P. intermedia. 3 Its functional role is produce a variety of potential virulence factors as a significant pathogen in the progression of health to disease. 5 Besides gingival sulcular epithelial cells, P. gingivalis is able to attach onto human buccal epithelial cells in vitro. 6 Adding on, it is able to cause non-oral infections such as endocarditis and abscesses in lung, head, neck and abdominal area. 7 P.gingivalis has also been cultured to study its significance in attachment and invasion of host cells 4, as well as to study internalization within host cells. 8

Examples of citations ^[1], ^[2]

Genome structure

P. gingivalis strain W38 has a genome structure of 2,343,479 bp consisting of an average GC content of 48.3%. 9 It contains 4 ribosomal operons (5S-23S-tRNA Ala-tRNA Ile-tRNA 16S), 2 structural RNA genes, 53 tRNA genes coding for all 20 amino acids. 9 P. gingivalis genes encode 3 restriction system proteins (PG0971, PG0968, PG1469), hemagglutinin proteins B and C (Hag B, PG1972, Hag C, PG1975), various capsular synthesis proteins, 20 transposase genes and 2 large mobile elements (PG1473 to PG1480). 9

Cell structure and metabolism

Cell Wall

P.gingivalis uses its cell wall to attach and provide resistance to saliva flow, which is mediated by adhesins on surface of bacteria and by receptors on oral surfaces. These adhesins are associated with cell structures such as capsules and fimbriae of P.gingivalis. The cell wall consists of distal polysaccharide (O-antigen), a non-repeating core oligosaccharide and a hydrophobic domain known as lipid A (endotoxin). Lipid A, the inner-most part of cell wall, is the biological active site of lipopolysaccharide (LPS) that can cause deregulation of the mammalian innate immune system by interacting with both toll-like receptors 2 and 4. Lipid A has different acylation patterns that change according to microenvironmental conditions, affecting host immune signaling to facilitate bacterial survival in the host. LPS of gram-negative bacteria is significant in maintainance of cellular and structural integrity, as well as controlling entry of hydrophobic molecules and toxic chemicals. P. gingivalis LPS also inhibits osteoblastic differentitation and mineralization in periodontal ligament stem cells for periodontal tissue regeneration. 10

Biofilm Formation

Motility

P. gingivalis is a non-motile bacterium.

Metabolic Functions

Ecology

Aerobe/anaerobe, habitat (location in the oral cavity, potential other environments) and microbe/host interactions.

Major habitat of P. gingivalis is the subgingival sulcus of the human oral cavity. 3 It requires fermentation of amino acids for energy production needed for its survival in deep periodontal pocket, with low sugar availability. 11 P. gingivalis is usually found in periodontal pockets, but can be potentially found in supragingival plaque and oral mucosal surfaces, dorsum of the tongue, and pharynx. 12 P. gingivalis/host interaction is classified under amphibiosis, where the recent relationship between the host and microbe can change, which in this case P. gingivalis increases along with dental plaques. 13 Host physiological processes such as cell activation, proliferation, differentiation, metabolism and cellular motilities need cell-to-cell or cell-to-extracellular matrix (ECM) contacts. Cellular integrins function as ECM protein receptors for the linkage between the extracellular environment and intracellular cytoskeleton. 14 ECM proteins in periodontal pocket fluid include vitronectin and fibronectin. Vitronectin protects gingival epithelium, as well as connective tissues against periodontal damages (31). Fibronectin is significant in proliferation and chemotaxis of periodontal ligament cells. 15 P. gingivalis binds to ECM proteins through its fimbriae and outer membrane proteins, inhibiting the ECM proteins from functioning, therefore slowing the recovery processes caused by periodontal tissue destructions. P. gingivalis is able to bind to β2 integrin on mouse peritoneal macrophages, leading to expressions of interleukin (IL)-1β and tumor necrosis factor (TNF)-α genes. Arginine-specific protease (Arg-gingipain) complex of P. gingivalis disrupts fibronectin and its receptor to block the receptor-ligand interactions of human host fibroblasts. This leads to the inhibition of cellular signal transduction through ECM proteins and its receptors, enhancing tissue destruction. 15 P. gingivalis internalizes into host gingival epithelial 16 and endothelial cells through membrane ruffles. 17 These ruffles surround P. gingivalis, therefore internalizing it and exist as vacuoles 18 to replicate and persist within these cells. 19 The intracellular environment provides nutrients for P. gingivalis growth, and serves as a protection against host immune system. 15 P. gingivalis fimA genes have 5 variants (type I to V) which is classified based on the nucleotide sequences 20 Polymerase chain reaction (PCR) is used to detect these variants of P. gingivalis in saliva and dental plaque samples from periodontal patients. 21 It was shown that the majority of samples collected contained type II fimA, and followed by type IV. On the contrary, type I was found in healthy individuals. Type III and V were less prevalent in the samples. These findings illustrate the presence of disease and non-disease causations of P. gingivalis, where the fimbriae variations are associated with bacterial infections that affect disease development. Type II fimA was also observed to invade rapidly into host epithelial cells, promoting P. gingivalis invasion. 22

Pathology

Do these microorganisms cause disease in the oral cavity or elsewhere?

The bacteria has also been identified as a risk factor for coronary heart disease, pulmonary infections and pre-term, low birth weight deliveries. 23 P. gingivalis produces a variety of virulence factor to penetrate gingivae and causes tissue destruction directly or indirectly, by inducing inflammation. These virulence factors are constituents or metabolites important in different stages of life cycle and can cause damage to the host. To survive and multiply in a host, P. gingivalis has to overcome host external protective barrier before finding a suitable environment for colonization, which occurs only in presence of virulence factors such as fimbriae, capsules, lipopolysaccharide (LPS), lipoteichoic acids, haemagglutinins, gingipains, outer membrane proteins and outer membrane vesicles. Expression of viulence factors is regulated in response to external environment changes of peridontopathogen. 3

Application to biotechnology

Bioengineering, biotechnologically relevant enzyme/compound production, drug targets,…

Current research

Summarise some of the most recent discoveries regarding this species.

References

References examples

1. Sahm, K., MacGregor, B.J., Jørgensen, B.B., and Stahl, D.A. (1999) Sulphate reduction and vertical distribution of sulphate-reducing bacteria quantified by rRNA slotblot hybridization in a coastal marine sediment. Environ Microbiol 1: 65-74.

2. Human Oral Microbiome

↑ MICR3004

This page is written by Jolene Sim for the MICR3004 course, Semester 2, 2016

[1] MICR3004

[1]

@@ Line 11: / Line 11: @@
 Bacteria – Bacteria – Bacteroidetes – Bacteroidia – Bacteroidales – Porphyromonadaceae – Porphyromonas <sup>[[1]]</sup>
 ===Species===
-Species name: Porphyromonas gingivalis
+Species name: ''Porphyromonas gingivalis''
 Type strain: W38 [[2]] (consult LPSN http://www.bacterio.net/index.html for this information)
@@ Line 17: / Line 17: @@
 ==Description and significance==
-Porphyromonas gingivalis (P. gingivalis) is a non-motile, asaccharolytic, gram negative bacteria [[3]].
+''Porphyromonas gingivalis'' (''P. gingivalis'') is a non-motile, asaccharolytic, rod-shaped gram negative bacteria. [[3]] It is obligately anaerobic which requires iron for growth and forms black-pigmented colonies on blood agar plates. [[3]] ''P.gingivalis'' is significant in pathogenesis and progression of inflammations in periodontal diseases. [[3]] It is detected in 85.7% of subgingival plaque samples from chronic periodontal patients. [[3]] The disease initially occurs as acute inflammation of gingival tissue, and untreated infections progressively cause formation of teeth pockets and loss of teeth. [[3]] Habitat of ''P. gingivalis'' is subgingival sulcus of human oral cavity, and serves as secondary colonizer of dental plaques by attaching onto parimary colonizers such as ''Streptococcus gordonii'' and ''P. intermedia''. [[3]] Its functional role is produce a variety of potential virulence factors as a significant pathogen in the progression of health to disease. [[5]] Besides gingival sulcular epithelial cells, ''P. gingivalis'' is able to attach onto human buccal epithelial cells ''in vitro''. [[6]] Adding on, it is able to cause non-oral infections such as endocarditis and abscesses in lung, head, neck and abdominal area. [[7]] ''P.gingivalis'' has also been cultured to study its significance in attachment and invasion of host cells [[4]],  as well as to study internalization within host cells. [[8]]
- Examples of citations <sup>[[#References|[1]]]</sup>, <sup>[[#References|[2]]]</sup>
+Examples of citations <sup>[[#References|[1]]]</sup>, <sup>[[#References|[2]]]</sup>
 ==Genome structure==
-Select a strain for which genome information (e.g. size, plasmids, distinct genes, etc.) is available.
+''P. gingivalis'' strain W38 has a genome structure of 2,343,479 bp consisting of an average GC content of 48.3%. [[9]] It contains 4 ribosomal operons (5S-23S-tRNA Ala-tRNA Ile-tRNA 16S), 2 structural RNA genes, 53 tRNA genes coding for all 20 amino acids. [[9]] ''P. gingivalis'' genes encode 3 restriction system proteins (PG0971, PG0968, PG1469), hemagglutinin proteins B and C (Hag B, PG1972, Hag C, PG1975), various capsular synthesis proteins, 20 transposase genes and 2 large mobile elements (PG1473 to PG1480). [[9]]
 ==Cell structure and metabolism==
-Cell wall, biofilm formation, motility, metabolic functions.
+===Cell Wall===
+''P.gingivalis'' uses its cell wall to attach and provide resistance to saliva flow, which is mediated by adhesins on surface of bacteria and by receptors on oral surfaces. These adhesins are associated with cell structures such as capsules and fimbriae of ''P.gingivalis''. The cell wall consists of distal polysaccharide (O-antigen), a non-repeating core oligosaccharide and a hydrophobic domain known as lipid A (endotoxin). Lipid A, the inner-most part of cell wall, is the biological active site of lipopolysaccharide (LPS) that can cause deregulation of the mammalian innate immune system by interacting with both toll-like receptors 2 and 4. Lipid A has different acylation patterns that change according to microenvironmental conditions, affecting host immune signaling to facilitate bacterial survival in the host. LPS of gram-negative bacteria is significant in maintainance of cellular and structural integrity, as well as controlling entry of hydrophobic molecules and toxic chemicals. P. gingivalis LPS also inhibits osteoblastic differentitation and mineralization in periodontal ligament stem cells for periodontal tissue regeneration. [[10]]
+===Biofilm Formation===
+===Motility===
+''P. gingivalis'' is a non-motile bacterium.
+===Metabolic Functions===
 ==Ecology==
 Aerobe/anaerobe, habitat (location in the oral cavity, potential other environments) and microbe/host interactions.
+Major habitat of P. gingivalis is the subgingival sulcus of the human oral cavity. [[3]] It requires fermentation of amino acids for energy production needed for its survival in deep periodontal pocket, with low sugar availability. [[11]] ''P. gingivalis'' is usually found in periodontal pockets, but can be potentially found in supragingival plaque and oral mucosal surfaces, dorsum of the tongue, and pharynx. [[12]] P. gingivalis/host interaction is classified under amphibiosis, where the recent relationship between the host and microbe can change, which in this case P. gingivalis increases along with dental plaques. [[13]] Host physiological processes such as cell activation, proliferation, differentiation, metabolism and cellular motilities need cell-to-cell or cell-to-extracellular matrix (ECM) contacts. Cellular integrins function as ECM protein receptors for the linkage between the extracellular environment and intracellular cytoskeleton. [[14]] ECM proteins in periodontal pocket fluid include vitronectin and fibronectin. Vitronectin protects gingival epithelium, as well as connective tissues against periodontal damages (31). Fibronectin is significant in proliferation and chemotaxis of periodontal ligament cells. [[15]] P. gingivalis binds to ECM proteins through its fimbriae and outer membrane proteins, inhibiting the ECM proteins from functioning, therefore slowing the recovery processes caused by periodontal tissue destructions. P. gingivalis is able to bind to β2 integrin on mouse peritoneal macrophages, leading to expressions of interleukin (IL)-1β and tumor necrosis factor (TNF)-α genes. Arginine-specific protease (Arg-gingipain) complex of P. gingivalis disrupts fibronectin and its receptor to block the receptor-ligand interactions of human host fibroblasts. This leads to the inhibition of cellular signal transduction through ECM proteins and its receptors, enhancing tissue destruction. [[15]] ''P. gingivalis'' internalizes into host gingival epithelial [[16]] and endothelial cells through membrane ruffles. [[17]] These ruffles surround ''P. gingivalis'', therefore internalizing it and exist as vacuoles [[18]] to replicate and persist within these cells. [[19]] The intracellular environment provides nutrients for P. gingivalis growth, and serves as a protection against host immune system. [[15]] P. gingivalis fimA genes have 5 variants (type I to V) which is classified based on the nucleotide sequences [[20]] Polymerase chain reaction (PCR) is used to detect these variants of P. gingivalis in saliva and dental plaque samples from periodontal patients. [[21]] It was shown that the majority of samples collected contained type II fimA, and followed by type IV. On the contrary, type I was found in healthy individuals. Type III and V were less prevalent in the samples. These findings illustrate the presence of disease and non-disease causations of P. gingivalis, where the fimbriae variations are associated with bacterial infections that affect disease development. Type II fimA was also observed to invade rapidly into host epithelial cells, promoting P. gingivalis invasion. [[22]]
 ==Pathology==
 Do these microorganisms cause disease in the oral cavity or elsewhere?
+The bacteria has also been identified as a risk factor for coronary heart disease, pulmonary infections and pre-term, low birth weight deliveries. [[23]] P. gingivalis produces a variety of virulence factor to penetrate gingivae and causes tissue destruction directly or indirectly, by inducing inflammation. These virulence factors are constituents or metabolites important in different stages of life cycle and can cause damage to the host. To survive and multiply in a host, ''P. gingivalis'' has to overcome host external protective barrier before finding a suitable environment for colonization, which occurs only in presence of virulence factors such as fimbriae, capsules, lipopolysaccharide (LPS), lipoteichoic acids, haemagglutinins, gingipains, outer membrane proteins and outer membrane vesicles. Expression of viulence factors is regulated in response to external environment changes of peridontopathogen. [[3]]
 ==Application to biotechnology==