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==Cell structure and metabolism== | ==Cell structure and metabolism== | ||
''V. parvula'' does not have a peptidoglycan layer | ''V. parvula'' is coccus shaped and does not have a peptidoglycan layer, therefore it is gram-negative organism. | ||
It is | It is a species that colonizes and survives acid environments such as in carious lesions in the oral cavity. | ||
RNA-seq studies | RNA-seq studies have pointed out that the histidine biosynthesis pathway is particularly upregulated in ''V. parvula''. It is presumed that high level of intra-cellullar histidine assist with an increased buffering capacity so the organism can adapt to the acidic environment. | ||
''V. parvula'' | It is generally appreciated that ''V. parvula'' depends on the production of lactate by other species, such as ''Streptococcus'', for its metabolism. The increased gene expression for lactate degradation indicates that ''V. parvula'' prefers short-chain organic acids as its main energy source <sup>[[#References|[4]]]</sup>. Adittionally, it has been found that ''Veillonella'' species have a metabolic activity that produces hydrogen sulfide (H2S) from L-cysteine. The increased production of H2S is correlated with an increase in lactate concentration leading to the formation of tongue biofilm and consequently malodor in the mouth. | ||
==Ecology== | ==Ecology== | ||
Revision as of 01:42, 22 September 2016
Emily Mantilla Bench B 31/08/2016 [1]
Classification
Higher order taxa
Prokaryote – Bacteria – Firmicutes – Negativicutes – Veillonellales – Veillonellaceae – Veillonella
Species
Veillonella parvula
Identified strains:
- Veillonella parvula AC2_8_11_AN_NA_2
- Veillonella parvula ACS-068-V-Sch12
- Veillonella parvula ATCC 17745
- Veillonella parvula DSM 2008
- Veillonella parvula HSIVP1
Description and significance
V. parvula is one of the six species belonging to the genus Veillonella which are gram-negative cocci and obligate anaerobes [1],[2]. It is a nonfermentative organism that lives optimally at 37 C and a PH range 6.5-8.0 thus it is commonly found in the human oral, intestinal and vaginal microflora. The NCBI genome record for strain DSM 2008 reports a collection date before 1898 in France, isolated from the intestinal tract [2]. It has been identified as a causal pathogen of endocarditis, bacterimia and opportunistic infection [2]. Several studies have confirmed that it has an important role in the formation of dental plaque biofilm favouring the association of other peridontal pathogens and contributing as causal agents of systemic diseases. The high prevalence of this pathogen in patients that have poor oral health has prompted to understand the role of V. parvula in health and disease as well as its contribution to the human microbiome.
Genome structure
There is complete genome available from the NCBI for "V. parvula DSM 2008" (RefSeq NC_013520.1). The genome has a size of 2.13 Mb with 1,893 genes, 9 pseudo-genes and 3 frameshift genes. The GC content is 38.6% and encodes 1,822 proteins. There are 12 rRNA, 48 tRNA and 2 other RNA [3].
Cell structure and metabolism
V. parvula is coccus shaped and does not have a peptidoglycan layer, therefore it is gram-negative organism. It is a species that colonizes and survives acid environments such as in carious lesions in the oral cavity. RNA-seq studies have pointed out that the histidine biosynthesis pathway is particularly upregulated in V. parvula. It is presumed that high level of intra-cellullar histidine assist with an increased buffering capacity so the organism can adapt to the acidic environment. It is generally appreciated that V. parvula depends on the production of lactate by other species, such as Streptococcus, for its metabolism. The increased gene expression for lactate degradation indicates that V. parvula prefers short-chain organic acids as its main energy source [4]. Adittionally, it has been found that Veillonella species have a metabolic activity that produces hydrogen sulfide (H2S) from L-cysteine. The increased production of H2S is correlated with an increase in lactate concentration leading to the formation of tongue biofilm and consequently malodor in the mouth.
Ecology
This pathogen has been isolated from the periodontal pocket and has a role in dental plaque biofilm formation in the human oral cavity. V. parvula requires lactate as a nutrient source so it is commonly found in association with other lactic-acid-producing species thus contributing to the cause of dental caries. Therefore it is established as the predominant species in subjects that have poor oral hygiene compared to those with moderate or good hygiene [1]. Moreover, it is found in the subgingival biofilm of patients with chronic periodontitis [3].
Pathology
V.parvula has been identified to have many pathogenic roles as well as being one of the organism responsible for bad mouthbreath. One study observed the distribution and frequency of oral Veillonella spp. and identified V. parvula as the predominant species in the subgingival biofilm of peridontal pockets and gingival sulcus in patients that presented chronic periodontitis [2]. Thus, it constitutes a peridontal pathogen that facilitates the biofilm colonization of more pathogens of this type such as Porphyromonas gingivalis [2].
Application to biotechnology
Bioengineering, biotechnologically relevant enzyme/compound production, drug targets,…
Current research
Summarise some of the most recent discoveries regarding this species.
References
3. NCBI Prokaryote Genome Annotation, Veillonella parvula DSM 2008
- ↑ MICR3004
This page is written by Emily Mantilla for the MICR3004 course, Semester 2, 2016
