Biology:Natronomonas

Short description: Genus of archaea

Natronomonas
Scientific classification
Domain:	Archaea
Kingdom:	Euryarchaeota
Phylum:	Euryarchaeota
Class:	Halobacteria
Order:	Halobacteriales
Family:	Halobacteriaceae
Genus:	Natronomonas Kamekura et al. 1997
Type species
Natronomonas pharaonis (Soliman & Truper 1983) Kamekura et al. 1997
Species
"N. aquatica" N. gomsonensis N. halophila "N. marina" N. moolapensis N. pharaonis N. salina N. salsuginis

Natronomonas (common abbreviation Nmn.) is a genus of the Halobacteriaceae.

Description and significance

Natronomonas pharaonis is an aerobic, extremely haloalkaliphilic archaeon that grows optimally in 3.5M sodium chloride and at pH 8.5, but is sensitive to high magnesium concentrations.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI).

16S rRNA based LTP_08_2023	53 marker proteins based GTDB 08-RS214
Natronomonas   "N. aquatica" García-Roldán et al. 2023         N. halophila     N. gomsonensis           N. moolapensis     N. pharaonis         N. salsuginis       "N. marina" Sun et al. 2023     N. salina	Natronomonas     N. halophila Yin et al. 2020     N. gomsonensis Kim et al. 2014         N. salina Yin et al. 2020       N. pharaonis (Soliman & Truper 1983) Kamekura et al. 1997       N. moolapensis Burns et al. 2010     N. salsuginis Duran-Viseras, Sanchez-Porro & Ventosa 2020

Genome structure

The genome of Natronomonas pharaonis consists of three circular replicons, the chromosome which is 2,595,221 bp in length, a typical haloarchaeal 131-kb plasmid, and a unique multicopy 23-kb plasmid. Its chromosome has a high G + C content (63.4%). Also, a high proportion of acidic amino acids (average 19.3%) is found in the proteins of N. pharaonis which results in low isoelectric points (average pI 4.6). This is considered to be one of the adaptive features of haloarchaea, which are known to apply the salt-in strategy (high internal salt concentrations) in order to survive in their hypersaline environment (Falb et al.). Further, it is noteworthy that because the archaeon lacks the genetic encoding for key enzymes for glycolytic pathways, it is not capable of sugar utilization.

Cell structure and metabolism

Natronomonas, like the other members of Halobacteriaceae, has a distinct physiological characteristics because it not only requires high NaCl concentrations but also high pH and low Mg2+ concentrations for growth. It usually utilizes amino acids as the carbon source, but the series of studies discovered that the archaeon has a high degree of nutritional self-sufficiency. Also, in contrast to other alkaliphiles, which use sodium Na+ instead of protons H+ as coupling ion between respiratory chain and ATP synthase, Natronomonas uses protons as coupling ion.

The archaeon grows under highly alkaline conditions of pH around 11, which causes reduced levels of ammonia in addition to low availability of metal ions. The genome analysis shows that, in its nitrogen metabolism process, the archaeon has three mechanisms that supply ammonia, which is then assimilated into glutamate: direct uptake of ammonia, uptake of nitrate and subsequent reduction to ammonia, and uptake of urea which is split by urease to release ammonia. The green arrows in the figure represent the transporters for exogenous nitrogen source ammonia (AmtB), nitrate (NarK), and urea (UrtA-E), and the blue arrows represent the enzymes for reduction of nitrate (NarB + Nir A) and hydrolysis of urea (UreA-G). Other abbreviations: GlnA + GltB = glutamate; 2-OG = oxoglutarate; fdx = ferredoxin.

It is probable that Natronomonas uses ferredoxin and not NADH as the electron donor for all three reductive conversions. This is evident from the occurrence of conserved ferredoxin-binding residues within the N. pharaonis NirA protein and ferredoxin dependence of nitrate and nitrite reductases in the halophile Haloferax mediterranei.

Ecology

Strains of N. pharaonis were first isolated from highly saline soda lakes in Egypt and Kenya, which show pH values around 11.

See also

• List of Archaea genera

Further reading

Scientific journals

• Oren A; Ventosa A (2000). "International Committee on Systematic Bacteriology Subcommittee on the taxonomy of Halobacteriaceae. Minutes of the meetings, 16 August 1999, Sydney, Australia". Int. J. Syst. Evol. Microbiol. 50 (3): 1405–1407. doi:10.1099/00207713-50-3-1405. PMID 10843089. 
• Kamekura M; Dyall-Smith ML; Upasani V; Ventosa A et al. (1997). "Diversity of alkaliphilic halobacteria: proposals for transfer of Natronobacterium vacuolatum, Natronobacterium magadii, and Natronobacterium pharaonis to Halorubrum, Natrialba, and Natronomonas gen. nov., respectively, as Halorubrum vacuolatum comb. nov., Natrialba magadii comb. nov., and Natronomonas pharaonis comb. nov., respectively". Int. J. Syst. Bacteriol. 47 (3): 853–857. doi:10.1099/00207713-47-3-853. PMID 9226918. 
• Natarajan, Janani; Schultz, Anita; Kurz, Ursula; Schultz, Joachim E. (2014). "Biochemical characterization of the tandem HAMP domain from Natronomonas pharaonis as an intraprotein signal transducer". FEBS Journal 281 (14): 3218–3227. doi:10.1111/febs.12855. PMID 24863503. 

Scientific books

• Gibbons, NE (1974). "Family V. Halobacteriaceae fam. nov.". in RE Buchanan. Bergey's Manual of Determinative Bacteriology (8th ed.). Baltimore: The Williams & Wilkins Co.. ISBN 978-0-683-01117-3. https://archive.org/details/bergeysmanualofd00atio. 

Scientific databases

• PubMed references for Natronomonas
• PubMed Central references for Natronomonas
• Google Scholar references for Natronomonas

External links

• NCBI taxonomy page for Natronomonas
• Search Tree of Life taxonomy pages for Natronomonas
• Search Species2000 page for Natronomonas
• MicrobeWiki page for Natronomonas
• LPSN page for Natronomonas
• Type strain of Natronomonas pharaonis at BacDive - the Bacterial Diversity Metadatabase

Wikidata ☰ Q6980258 entry