Halococcus

Halococcus (common abbreviation: Hcc.) is a genus of the Halococcaceae.

Halococcus
Scientific classification
Domain:	Archaea
Kingdom:	Euryarchaeota
Phylum:	Euryarchaeota
Class:	Halobacteria
Order:	Halobacteriales
Family:	Halococcaceae
Genus:	Halococcus Schoop 1935
Type species
Halococcus litoralis (Poulsen 1879) Schoop 1935
Species
H. agarilyticus H. dombrowskii H. hamelinensis H. morrhuae H. qingdaonensis H. saccharolyticus H. salifodinae H. salsus H. sediminicola H. thailandensis

Ecology

Halococcus is a genus of extreme halophilic archaea, meaning that they require high salt levels, sometimes as high as 32% NaCl, for optimal growth. Halophiles are found mainly in inland bodies of water with high salinity, where their pigments (from a protein called rhodopsinprotein) tint the sediment bright colors. Rhodopsinprotein and other proteins serve to protect Halococcus from the extreme salinities of their environments. Because they can function under such high-salt conditions, Halococcus and similar halophilic organisms have been used in the food industry and even in skin-care products.

Halococcus is found in environments with high salt levels, mainly inland bodies of salt water, but some may be located in highly salted soil or foods. The pigmented proteins in some species cause the reddish tint found in some areas of the Dead Sea and the Great Salt Lake, especially at the end of the growing season. When under cultivation, the organisms grew best under high salinity conditions.

Genome structure

The genome of multiple halococcus species have been sequenced. The 16s rDNA of a species has demonstrated its placement on the phylogenetic tree. Due to the organisms' potential longevity, Halococcus may be a good candidate for exploring taxonomic similarities to life found in outer space.

Cell structure and metabolism

Halococcus species are able to survive in high-saline habitats because of chlorine pumps that maintain osmotic balance with the salinity of their habitat, and thus prevent dehydration of the cytoplasm.

The cells are cocci, 0.6–1.5 micrometres long with sulfated polysaccharide walls. The cells are organtrophic, using amino acids, organic acids, or carbohydrates for energy. In some cases, they are also able to photosynthesize.

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_06_2022	53 marker proteins based GTDB 08-RS214
H. salifodinae Denner et al. 1994 H. agarilyticus Minegishi et al. 2015 H. saccharolyticus Montero et al. 1990 H. hamelinensis Goh et al. 2006 H. salsus Chen et al. 2018 H. sediminicola Yim et al. 2014 H. thailandensis Namwong et al. 2007 H. qingdaonensis Wang et al. 2007 H. dombrowskii Stan-Lotter et al. 2002 H. morrhuae (Farlow 1880) Kocur & Hodgkiss 1973	H. agarilyticus H. saccharolyticus H. salifodinae H. hamelinensis H. salsus H. sediminicola H. morrhuae [incl. Halococcus dombrowskii] H. qingdaonensis H. thailandensis

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.
• Schoop, G (1935). "Halococcus litoralis, ein obligat halophiler Farbstofflbildner". Deutsche Tierärztliche Wochenschrift. 43: 817–820.

Scientific books

• Gibbons, NE (1974). "Family V. Halobacteriaceae fam. nov.". In RE Buchanan; NE Gibbons (eds.). Bergey's Manual of Determinative Bacteriology (8th ed.). Baltimore: The Williams & Wilkins Co. ISBN 0-683-01117-0.