Studies ofmicrobial flora in the subtropics and collection of their cultures

本研究旨在调查日本亚热带地区的真菌、酵母菌、细菌和放线菌等微生物菌群，并对其进行分离培养，并通过对其生活史和生态学的研究，了解其适应亚热带环境的特性。研究地点是西南群岛（奄美岛）。在冲绳。石垣是。从1999年到2002年，我们定期收集样本。我们的目标是：1)寄生于红树林和海岸落叶、海藻等的水生真菌，2)寄生于森林、田野和红树林根际的土壤真菌，3)寄生于活叶内的内生真菌，3)寄生于土壤、花朵、果实等的酵母，4)海洋细菌（尤其是黄杆菌群），5)寄生于土壤中的稀有放线菌。我们获得了许多分离株，包括许多未描述的物种，其中一些我们已经描述为新的分类群。对部分分离真菌的生态学研究表明，亚热带菌株与同一物种的热带菌株具有不同的特性，表现出对亚热带环境条件的特异性适应。鉴定获得的分离株后，将其存放在IFO（一个开放的公共培养库）的培养集中，供公共使用，用于基础科学和应用科学。目前正在进行的进一步的分类学研究将导致新的分类群的描述，并对微生物分类学的进展作出贡献。

This study was aimed to investigate flora of microbes, such as fungi, yeasts, bacteria and actinomycetes, inhabiting subtropical regions in Japan and to isolate the strains for depositing them into the collection, and also to understand their properties adapting to the subtropical environments by studying their life cycle and ecology. The research sites were the South-West Islands (Amami Is., Okinawa Is., Ishigaki Is., and Iriomote Is.) of Japan, where we collected samples regularly from 1999 to 2002. We targeted 1) aquatic fungi inhabiting fallen leaves, seaweeds, etc. at mangroves and seashore, 2) soil fungi inhabiting forest, fields and mangrove rhizosphere, 3) endophytic fungi living within living leaves, 3) yeasts inhabiting soil, flowers, fruits, etc., 4) marine bacteria (especially Cytophaga-Flavobacterium group), and 5) rare actinomycetes inhabiting soil. We obtained a number of isolates including many undescribed species, some of which we have already described as new taxa. Ecological study on some of the isolated fungi revealed that subtropical strains have different properties from those of the tropical strains of the same species, which showed specificity adapting to the subtropical environmental conditions. After identification of the obtained isolates, they were deposited the culture collection of IFO, an open-public culture collection, for public use for basic and applied science. Further taxonomic studies, which are now going on, will result in description of new taxa and also in contribution to a progress in microbial taxonomy.