Haloterrigena turkmenica

Haloterrigena turkmenica is an aerobic chemo organotrophic archeon originally found in Turkish salt lakes. Haloterrigena turkmenica is a halophilic archeon that was first isolated from sulfate saline soil located in Turkmenistan. However, it wasn't until 2008 that H. turkmenica was successfully grown in the lab on Horikoshi medium. The Horikoshi medium is composed of yeast extract, glucose, potassium phosphate (KHPO4), peptone, Magnesium sulfate (MgSO4), water, and sodium carbonate (NaCO3). Haloterrigena turkmenica was initially placed in the family Halobacteriaceae as Halococcus turkmenicus by Zyaginsteva and Tarasov in 1987. In 1999, Ventosa et al. published a proposal that would transfer the following species to Haloterrigena turkmenica, which is a new genera: Halococcus turkmenicus, Halobacterium trapanicum JCM 9743 and strain GSL-11. The proposal was in response to Ventosa having found significant genetic differences between H. turkmenicus and other organisms in the Halococcus genera. The proposal was accepted and the organism is now classified under this new novel genera. The name Haloterrigena comes from the halos which mean salt and terrigena which means of or from Earth. Turkmenica was proposed by Zvyaginseva and Tarasov in 1987. This name comes from the fact that this species was first collected from the Turkish salt lakes. Haloterrigena turkmenica is a gram-negative organism. Cells are typically found as individuals, but have been seen in the form of pairs and tetrads. Cell shape can be classified as being ovoid to coccoid in shape. The diameter of the cells ranges from 1.5 µm to 2.0 µm. On growth medium, colonies of H. turkmenica appear elevated, red in color and circular. The red color is due to the presence of C50-carotenoids. There have been conflicting reports on the optimum growth temperature. According to Selim et al., the optimum growth temperature for H. turkmenica is 40 °C, while Saunders et al. reports that the optimum growth temperature is 51 °C. However, both reports state that the temperature growth range is between 29°-57 °C. H. turkmenica has been documented to best grow at NaCl concentrations around 3.4M. However, it can tolerate salt concentrations from 2-4.5M NaCl. At a pH of 9, H. turkmenica as been shown to grow best. It will tolerate a pH within the range of 8.5 to 11.