Additional distribution catalogues of long linear and branched polyamines in thermophilic bacteria including acidophiles, alkaliphiles and halophiles and their significance for extremophily and chemotaxonomy were presented. Cellular polyamines acid-extracted from 85 newly validated and available thermophiles spread into the following ten taxa were analyzed by high-performance liquid chromatography, gas chromatography and gas chromatography-mass spectrometry. 1) Within the order Thermotogales, linear penta-amines were found in Marinitoga, Thermotoga, Kosmotoga, Thermosipho and Fervidobacterium, but not in Petrotoga, Oceanitoga, Defluvitoga and Mesotoga. Linear hexaamines were detected limitedly in Kosmotoga, Thermotoga and Thermosipho. 2) Linear penta-amines and hexa-amines were distributed throughout the extremely thermophilic Thermus, Marinithermus and Vulcanithermus in the order Thermales. Penta-amines and hexa-amines were not detected in the moderately thermophilic Meiothermus, Oceanithermus and Rhabdothermus. N4 -bis(aminopropyl) norspermidine and N4 -bis(aminopropyl)spermidine were found in Thermus thermophilus alone. 3) Moderate/extreme thermophiles distributed throughout the order Aquificales contained one of the quaternary-branched penta-amines. 4) A branched penta-amine was distributed in Thermodesulfatator whereas Thermodesulfobacterium contained linear and branched penta-amines in the order Thermodesulfobacteriales. 5) Thermaerobacter contained linear penta-amines and hexa-amines, whereas Caldicoprobacter contained N4 -bis(aminopropyl)spermidine from the order Clostridiales. 6) In the order Thermoanaerobacterales, linear and branched penta-amines were distributed in Thermoanaerobacterium as well as in Ammonifex, Caldanaerobacter, Caldicellulosiruptor, Desulfovirgula, Fervidicola, Moorella, Thermanaeromonas, Thermovorax and Thermoanaerobacter, but not in Carboxydothermus, Calderihabitans, Thermodesulfobium and Coprothermobacter. 7) In the order Bacillales, a tertiary branched pentaamine, N4 -aminopropylspermine, was found in Geobacillus. Thermopentamine, homothermohexamine and N4 -bis(aminopropyl)spermidine were distributed throughout Saccharococcus, Hydrogenibacillus, Caldalkalibacillus and Thermobacillus. 8) Caldisericum belonging to the order Caldisericales contained a tertiary-branched tetra-amine, N4 -aminopropylspermidine. 9) Desulfothermus located in the order Desulfovibrionales contained N4 -bis(aminopropyl)spermidine. 10) Rhodothermus of the family Rhodothermaceae contained linear and branched penta-amines and a linear hexa-amine, homothermohexamine.

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Superoxide dismutase (SOD) is an enzyme that alternately catalyzes the dismutation of anion radicals in living cells. Manganese type SOD (MnSOD) has been purified and partially characterized from the thermophilic bacteria; Bacillus stearothermophilus strain C36. The purification was achieved using a column chromatography on Sephacryl S-200 in the presence of lauryl dodecyl sulfate (SDS). SDS was used to separate MnSOD from other proteins. The final recovery rate was 33 %. This recovery rate was much higher than other authentic methods (1.6 % – 13.6 %). This SDS-containing gel chromatography was available for the purification of a protein from the other thermophile.

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How did living things appear on early earth? Answering this question is a large challenge for human being. This question is separated to two different questions: how can a living thing emerge from an assembly of molecules and can such an emergence occur on early earth. We are attempting to answer the former question by constructing life-like systems in a test tube. To date, we have constructed an artificial genome RNA replication system by combining an artificial genome RNA, the reconstituted translation system of Escherichia coli, and micro-scale water droplets dispersed in oil (water-in-oil emulsion). This system has several characteristics of living things, the translation of a gene, the replication of genome, and spontaneous evolution. By using this system as a starting point, we believe that we can develop a life-like system indistinguishable from natural living cells, and through the construction we would find an answer to the first question.

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[in Japanese]

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The study of the origin and evolution of life cannot be separated from the study of the origin and evolution of the Earth. In this paper, I focused on the latter studies to understand how our planet was formed and how its early environment was evolved. First, I reviewed the over-all formation and evolution of the solar system based on “Kyoto model.” Then, I proposed a new scenario of the early evolution of terrestrial planets especially for the Earth’s early environment. Through these scenarios, I discussed how to make a habitable planet and what mechanisms are essential to make a planet habitable. The university and diversity of the evolution of life in the Universe is one of the key questions to understand the origin and evolution of life on our Earth. However, these questions are highly complicated and cannot be solved through astronomy alone. I believe that multidisciplinary integration of planetary science, geology, and biology is imperative to promote the new science-field, Astrobiology.

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For a long time the combination of stresses (vacuum, space radiation, space UV, temperature fluctuations) of outer space was believed to be lethal for terrestrial organisms and, thus, idea of possibility of interplanetary transfer of life was not supported by any experimental evidence. During the last decades, a set of international space research programs (“Expose-R”, “Biorisk 1-3”, “Stone”, “Biopan”, etc.) revealed that some groups of microorganisms and animals are resistant to the outer space exposure and potentially capable to interplanetary transfer, including re-entry into the atmosphere. The absolute majority of the organisms resistant to the harsh outer space environment are presented by anhydrobiotic (even of the Earth capable to surviving without water) species. A midge Polypedilum vanderplanki (a.k.a. the sleeping chironomid) is the most complex, yet believed to be “evolutionary the youngest” animal with ability to anhydrobiosis. The confirmed survival and further reproduction after months of outer space exposure here is a cumulative result of evolutionary traits providing this insect with anhydrobiotic abilities.

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