Development of Cryopreservation Technique and Its Diffusion in South-east Asia for Conservation of Tropical Plant Germplasms Useful for Search for Bioactive Metabolites.

本研究探讨了适用于高等植物、微藻等光合作用生物热带种质的超低温保存技术，为药学领域寻找新的生物活性代谢物提供参考。我们还试图将这些技术推广到东南亚国家，这些国家的热带雨林生态系统被环境污染迅速破坏，许多珍贵的高等植物和微藻物种正濒临灭绝。作为一项利用植物根和绿藻进行的基础研究，我们发现一种植物激素-脱落酸(ABA)可以诱导对脱水和冰冻的耐受性。ABA处理提高了这些材料在液氮中冷冻后的存活率。我们将这种预处理应用于几种植物和藻类，并成功地对它们进行了超低温保存。我们试图与国外研究人员合作，在这些地区的微藻中寻找新的生物活性代谢物。从泰国和印度尼西亚分离的淡水蓝藻中分离到几种具有较强生长抑制活性的代谢产物和一种生物表面活性物质。最后，我们努力推广泰国和印度尼西亚发展起来的超低温保存技术，作为保护有用的热带植物和藻类种质的普遍适用技术。我们多次访问了这些国家，并举办了讲座和技术研讨会，以鼓励人们对热带种质重要性的认识，并增加个人的超低温保存技术。

In this research, we investigated the cryopreservation techniques generally applicable to tropical germplasms of photosynthetic organisms such as higher plants and microalgae useful for searching novel bioactive metabolites in Pharmaceutical Science field. We also attempted to diffuse these techniques in South-east Asian countries in which ecosystem in rainforest is rapidly destructed by environmental pollution many precious species of higher plants and microalgae are on the way to extinction.As a fundamental research using plant root and green alga, we found a phytohormone, abscisic acid(ABA), could induce tolerance to dehydration and then freezing. ABA-pretreatment increased the survival rates in these materials after freezing in liquid nitrogen. We applied this pretreatment to several plants and algae and succeeded their cryopreservation.We attempted to search novel bioactive metabolites in microalgae in those areas under cooperation with foreign researchers. Several metabolites showing strong growth inhibitory activities and a biosurfactant could be isolated from freshwater cyanobacteria isolated in Thailand and Indonesia.Finally, we made efforts to diffuse the developed cryopreservation techniques in Thailand and Indonesia as generally applicable ones for conservation of useful tropical plant and algal germplasms. We visited these countries several times and gave lectures and technical workshops to encourage the consciousness for importance of tropical germplasms and increase the individual techniques of cryopreservation.