In taxonomy

Alpha taxonomy

Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...

, Halorhabdus is a genus of the Halobacteriaceae

Halobacteriaceae

In taxonomy, the Halobacteriaceae are a family of the Halobacteriales in the domain Archaea.- Overview :Halobacteriaceae are found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less...

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Description and significance

Halorhabdus utahensis (salt-loving rod) is a motile, Gram-negative, extremely halophilic archaeon that forms red, circular colonies. It grows at the temperatures between 17 and 55 °C, with optimal growth occurring at 50°C. It can also grow over a pH range of 5.5-8.5 with the optimal pH value between 6.7 and 7.1. Further, with its extremely high salinity optimum of 27% NaCl, Halorhabdus has one of the highest reported salinity optimum of any living organism.

Genome structure

The genome of Halorhabdus is yet to be sequenced. The G + C content of its DNA is estimated to be 64%.

Cell structure and metabolism

The cells of Halorhabdus utahensis are extremely pleomorphic, exhibiting anything from irregular coccoid or ellipsoid to triangular, club-shaped or rod-shaped forms. The rod-shaped and ellipsoid cells are 2-10 * 0.5-1 µm and 1-2 * 1 µm in size, respectivelly, and the spherical cells have a diameter of approximately 1 µm. The archaeon utilizes only a limited range of substrates, such as glucose, xylose, and fructose, for growth, and is unique in its inability to utilize yeast extract or peptone. Other substances that did not stimulate the organism's growth include organic acids, amino acids, alcohols, glycogen, and starch.

Ecology

The strains of Halorhabdus utahensis were isolated from samples from Great Salt Lake, Utah, USA.

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