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==Cell structure and metabolism== | ==Cell structure and metabolism== | ||
Cell wall, biofilm formation, motility, metabolic functions. | Veillonella parvula has a morphology of a coccus bacteria, and since it is a gram negative bacteria, the cell wall structure consist of an outer membrane, consisting of mainly lipopolysaccharide. The peptidoglycan of veillonellae is of the A1γ-type with glutamic acid in D configuration, diaminopimelic acid in meso configuration and covalently bound cadaverine or putrescine attached in α-linkage to glutamic acid. Besides that, the bacteria is also known to grows in pairs or short chains. | ||
Veillonellae are characterized by an unusual metabolism using methylmalonyl-CoA decarboxylase to convert the free energy derived from decarboxylation reactions into an electrochemical gradient of sodium ions [29]. They utilize the metabolic end products of co-existing carbohydrate-fermenting bacteria, i.e. lactic acid bacteria in the gastrointestinal tract, and thereby play an important role in a natural microbial food chain [6]. Another characteristic trait of veillonellae is their ability to form intergeneric coaggregates with other bacteria which occur in the same ecological niche [30]. Although Veillonella cannot adhere to surfaces itself, the bacterium is able to attach to specific surface structures present on other cells, often mediated by lectin-carbohydrate interactions [31]. The coaggregation creates a functional community providing nutrients and protection for all participants. | |||
Strain Te3T produces propionic and acetic acid, carbon dioxide and hydrogen from lactate and other organic acids like pyruvate, malate or fumarate. V. parvula cannot grow on succinate as a sole carbon source but can decarboxylate succinate during fermentation of lactate or malate [25]. Veillonellae are unable to use glucose or other carbohydrates for fermentation [26] and they do not possess a functional hexokinase [24]. Nitrate is reduced and arginine dihydrolase is produced. | |||
Another characteristic feature of V. parvula is the presence of plasmalogens such as plasmenylethanolamine and plasmenylserine as major constituents of the cytoplasmic membrane. These ether lipids replace phospholipids and play an important role in the regulation of membrane fluidity [36]. | |||
Cell wall, biofilm formation, motility, metabolic functions. | |||
==Ecology== | ==Ecology== | ||
Revision as of 05:28, 17 September 2016
Lyman Ngiam Bench D 31/8/16** [1]
Classification
Higher order taxa
The order taxa for Veillonella Parvula is listed as below:
Kingdom – Domain – Phylum – Class – Order – Family – Genus
[Bacteria]-[Terrabacteria group]-[Firmicutes]-[Negativicutes]-[Veillonellales]-[Veillonellacea]-[Veillonella]
Species
There are a total of 14 species under the genus Veillonella. Veillonella parvula is one of the species name. There are many different description in terms of the strain, as listed below:
Type strain: strain ATCC10790 = CCUG 5123 = DSM 2008 = JCM 12972 = NCTC 11810
(consult LPSN http://www.bacterio.net/index.html for this information)
Description and significance
Veillonella parvula is a gram negative, anaerobic, coccus bacteria that is part of the normal flora of the mouth, gastrointestinal tract and vagina in humans. The microorganism is first discovered by Veillon and Zuber in 1898.
Generally, Veillonella parvula has been treated as normal commensal, however in rare cases, it can also cause infection as a pathogenic bacteria. Over the past years, reports has identified Veillonella species as a cause of endocarditis, obstructive pneumonitis, lung abscess, chronic sinusitis, chronic tonsillitis, liver abscess, and even meningitis. However,the most common reported infection caused by Veillonella parvula is osteomyelitis.
One of the significant feature of this microoganism is the ability to confer multi antimicrobial resistance properties to Streptococcus mutans, a primary pathogen in dental caries and thrives in dental plague. The resistance is obtained via formation of a dual species biofilm between Veillonella parvula and Streptococcus mutans.
Give a general description of the species (e.g. where/when was it first discovered, where is it commonly found, has it been cultured, functional role, type of bacterium [Gram+/-], morphology, etc.) and explain why it is important to study this microorganism. Examples of citations [1], [2]
Genome structure
The genome of Veillonella parvula type strain DSM 2008 consist of a single circular chromosome that is 2,132,142 bp longs with 38.6% of GC contents.
In terms of the gene identified, there are a total of 1920 genes that have been reported, however only 1859 of the genes are protein coding genes and 15 genes being identified as pseudogenes.
- insert table and figure**
Select a strain for which genome information (e.g. size, plasmids, distinct genes, etc.) is available.
Cell structure and metabolism
Veillonella parvula has a morphology of a coccus bacteria, and since it is a gram negative bacteria, the cell wall structure consist of an outer membrane, consisting of mainly lipopolysaccharide. The peptidoglycan of veillonellae is of the A1γ-type with glutamic acid in D configuration, diaminopimelic acid in meso configuration and covalently bound cadaverine or putrescine attached in α-linkage to glutamic acid. Besides that, the bacteria is also known to grows in pairs or short chains.
Veillonellae are characterized by an unusual metabolism using methylmalonyl-CoA decarboxylase to convert the free energy derived from decarboxylation reactions into an electrochemical gradient of sodium ions [29]. They utilize the metabolic end products of co-existing carbohydrate-fermenting bacteria, i.e. lactic acid bacteria in the gastrointestinal tract, and thereby play an important role in a natural microbial food chain [6]. Another characteristic trait of veillonellae is their ability to form intergeneric coaggregates with other bacteria which occur in the same ecological niche [30]. Although Veillonella cannot adhere to surfaces itself, the bacterium is able to attach to specific surface structures present on other cells, often mediated by lectin-carbohydrate interactions [31]. The coaggregation creates a functional community providing nutrients and protection for all participants.
Strain Te3T produces propionic and acetic acid, carbon dioxide and hydrogen from lactate and other organic acids like pyruvate, malate or fumarate. V. parvula cannot grow on succinate as a sole carbon source but can decarboxylate succinate during fermentation of lactate or malate [25]. Veillonellae are unable to use glucose or other carbohydrates for fermentation [26] and they do not possess a functional hexokinase [24]. Nitrate is reduced and arginine dihydrolase is produced.
Another characteristic feature of V. parvula is the presence of plasmalogens such as plasmenylethanolamine and plasmenylserine as major constituents of the cytoplasmic membrane. These ether lipids replace phospholipids and play an important role in the regulation of membrane fluidity [36].
Cell wall, biofilm formation, motility, metabolic functions.
Ecology
Aerobe/anaerobe, habitat (location in the oral cavity, potential other environments) and microbe/host interactions.
Pathology
Do these microorganisms cause disease in the oral cavity or elsewhere?
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
- ↑ MICR3004
This page is written by Lyman Ngiam Tze Kin for the MICR3004 course, Semester 2, 2016
