Polyamines of the hyperthermophilic archaebacteria belonging to the generaThermococcus and Methanothermus and two new genera Caldivirga and Palaeococcus

Cellular polyamines of eight new thermophilic archaebacteria were investiga ted to determine the chemotaxonomic significance of polyamine distribution profiles. Hyperthermoacidophilic Caldivirga maquilingensis belonging to the family Thermoproteaceae of the Crenarchaeota have a unique polyamine profi le comprising spermidine, norspermidine and norspermine as the major polyam ines. Within the order Thermococcales of the Euryarchaeota, the major polya mines of an extremely thermophilic terrestrial species of Thermococcus, T. zilligii, were spermidine and agmatine, whereas hyperthermophilic submarine species of Thermococcus and hyperthermophilic submarine Palaeococcus ferro philus contained a quaternary branched penta-amine, N-4-bis(aminopropyl)spe rmidine, as a major polyamine. A hyperthermophilic methanogen, Methanotherm us sociabilis, belonging to Euryarchaeota, contained spermidine and spermin e as the major polyamine.