[H-CG33] Useful life-support systems in closed bio-ecosystems

[HCG33-P03] The uniqueness of the dry heat tolerance of akinetes of terrestrial cyanobacterium Nostoc sp. HK-01

*Shunta Kimura^1,2,3, Kaori Tomita-Yokotani³ (1.Graduate School of Agricultural and Life Sciences, The University of Tokyo, 2.Japan Society for the Promotion of Science, 3.Faculty of Life and Environmental Sciences, University of Tsukuba)

Keywords:Akinete, Dry heat tolerance, Nostoc sp. HK-01, Terrestrial cyanobacteria

Terrestrial cyanobacteria are useful for enabling bio-chemical circulation in closed bio-ecosystems, which is achieved though their photosynthetic ability, nitrogen fixing ability and utility as a food. Dried colonies of the terrestrial cyanobacterium Nostoc sp. HK-01 have a high tolerance to vacuum, UV, gamma-rays, heavy particle beams, and extreme temperatures. Tolerance to extraterrestrial environments is important for transportation in space. Nostoc sp. HK-01 was adopted as a biological material for space exposure experiments (“TANPOPO” mission), because of their high environmental tolerances. Nostoc sp. HK-01 has several different types of cells in its life cycle. We have revealed that the akinete (dormant cell) cell type of Nostoc sp. HK-01 shows tolerance to dry heat. In this study, we tested the dry heat tolerances of cyanobacterial akinetes of several species. We will discuss the uniqueness of the dry heat tolerance of Nostoc sp. HK-01.