Haloferax volcanii

Haloferax volcanii is a species of organism in the genus Haloferax in the Archaea. Microbiologist Benjamin Elazari Volcani first discovered Haloferax volcanii, a self-named extremophile, in the 1930s. H. volcanii is a halophilic mesophile archaeon that can be isolated from hypersaline environments such as: the Dead Sea, the Great Salt Lake, and oceanic environments with high sodium chloride concentrates. Haloferax volcanii is noteworthy because it can be cultured without much difficulty, rare for an extremophile. H. volcanii is chemoorganotrophic, metabolizing sugars as a carbon source. It is primarily aerobic, but is capable of anaerobic respiration under anoxic conditions. Recently an isolate of this species was studied by researchers at University of California, Berkeley, as part of a project on the survival of haloarchaea on Mars. The genome of H. volcanii consists of a large (4 Mb), multicopy chromosome and several megaplasmids. The complete genome, DS2, of H. volcanii consists of about 4130 genes. The genome has been completely sequenced and a paper discussing it was published in 2010. The molecular biology of H. volcanii has been extensively studied for the last decade in order to discover more about DNA replication, DNA repair and RNA synthesis. The archaeal proteins used in these processes are extremely similar to Eukaryotic proteins and so are studied primarily as a model system for these organisms. H. volcanii undergoes prolific horizontal gene transfer through a mechanism of 'mating'- cell fusion. Reproduction among H. volcanii occurs asexually by binary fission. This practice is similar to that of other Archaea and, indeed, that of bacteria. H. volcanii cells have no cell wall and, like many archaea, therefore use their exterior S-layer for structure. An individual H. volcanii archaeon can vary from 1-3 micrometers in diameter. They are typically recognisable by their 'dished crisp' shape, but are somewhat pleiomorphic so may be seen in other shapes including coccoid.