''Haloarcula'' (common abbreviation ''Har.'') is a genus of extreme halophilic

Archaea Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even thou ...

in the class of

Halobacteria Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class (biology), class of prokaryotic archaea under the phylum Euryarchaeota, found in water Saturated and unsaturated compounds, saturated or nearly saturated with ...

Cell structure

''Haloarcula'' species can be distinguished from other genera in the family

Halobacteriaceae Halobacteriaceae is a family in the order Halobacteriales and the domain Archaea. ''Halobacteriaceae'' represent a large part of halophilic Archaea, along with members in two other methanogenic families, ''Methanosarcinaceae'' and ''Methanocalcul ...

by the presence of specific derivatives of TGD-2 polar lipids. ''H. quadrata'' has predominantly flat, square-shaped, somewhat pleomorphic cells.

Metabolism

''Haloarcula quadrata'' was first isolated when researchers were attempting to culture ''

Haloquadratum walsbyi ''Haloquadratum walsbyi'' is a species of Archaea in the genus ''Haloquadratum'', known for its square shape and halophilic nature. First discovered in a brine pool in the Sinai Peninsula of Egypt, ''H. walsbyi'' is noted for its flat, square- ...

'', a haloarchaeon that was thought to be unculturable until 2004. Similar to other halophilic archaea, ''Haloarcula'' species grow optimally at 40–45 °C. Growth appears in sheets of up to 65 cells often in the shape of a square or triangle.

Taxonomy

The genus of ''Haloarcula'' was long grouped with other halophilic archaea such as ''

Halobacterium ''Halobacterium'' (common abbreviation ''Hbt.'') is a genus in the family Halobacteriaceae. The genus ''Halobacterium'' ("salt" or "ocean bacterium") consists of several species of Archaea with an aerobic metabolism which requires an environm ...

'' until genomic analysis prompted to reorder this genus in the new family of

Haloarculaceae ''Haloarculaceae'' is a family of Halophile, halophilic and mostly chemoorganotrophic archaea within the order ''Halobacteriales''. The type genus of this family is ''Haloarcula.'' Its biochemical characteristics are the same as the order ''Halo ...

Phylogeny

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

(NCBI). Unassigned ''Haloarcula'' * "''H. ajinwuensis''" * "''H. algeriensis''" Kharroub et al. 2005b * "''H. altuensis''" * "''H. brevis''" Ma et al. 2024 * ''H. halobia'' Ma et al. 2024 * ''H. halophila'' Ma et al. 2024 * ''H. litorea'' Ma et al. 2024 * "''H. morrhuae''" Torreblanca et al. 1986 * ''H. ordinaria'' Ma et al. 2024 * ''H. pelagica'' Ma et al. 2024 * ''H. rara'' Ma et al. 2024 * "''H. regularis''" Ma et al. 2024 * "''H. sediminis''" Ma et al. 2024 * "''H. siamensis''" Namwong et al. 2007

Ecology

''Haloarcula'' species are found in neutral saline environments such as

salt lakes A salt lake or saline lake is a landlocked body of water that has a concentration of salts (typically sodium chloride) and other dissolved minerals significantly higher than most lakes (often defined as at least three grams of salt per liter). I ...

, marine salterns, and saline soils. Like other members of the family Halobacteriaceae, ''Haloarcula'' requires at least 1.5 M NaCl for growth, but grow optimally in 2.0 to 4.5 M NaCl.

References

External links

''Haloarcula'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Archaea genera Halobacteria {{archaea-stub