Polyamines of the thermophilic eubacteria belonging to the genera Aquifex,Thermodesulfobacterium, Thermus and Meiothermus, and the thermophilic archaebacteria belonging to the genera Sulfurisphaera, Sulfophobococcus, Stetteria, Thermocladium, Pyrococcus, Thermococcus, Methanopyrus and Methanothermus

Cellular polyamines of thermophilic eubacteria and archaebacteria were inve stigated for the chemotaxonomic significance of polyamine distribution prof iles within thermophiles. A quaternary branched penta-amine, N-4-bis(aminop ropyl)norspermidine, and another quaternary branched penta-amine, N-4-bis ( aminopropyl)spermidine, were the main polyamines in the thermophilic eubact eria, Aquifex pyrophilus and Thermodesulfobacterium mobile, respectively. T hese quaternary amines and linear hexa-amines were also found in Thermus th ermophilus but not detected in the new Thermus species, T. brockianus and T . oshimai, and Meiothermus species, M. chianophilus and M. silvanus. In new members of Crenarchaeota, Sulfurisphaera ohwakuensis contained norspermidi ne, spermidine, norspermine and spermine. in addition to these triamines an d tetraamines, Stetteria hydrogenophila and Thermocladium modestius contain ed homocardopentamine and/or thermopentamine, and Sulfophobococcus zilligii contained cadaverine and homospermidine. The main polyamine of the hyperth ermophilic Euryarchaeota, Pyrococcus horikoshii and Thermococcus fumicolans , was N-4-bis(aminopropyl)spermidine. Hyperthermophilic Methanothermus ferv idus and Methanopyrus kandleri contained spermidine, spermine and agmatine, and lacked long and branched polyamines, suggesting that the distribution of long and branched polyamines are not essential for thermophilic methanog ens.