立山積雪層に保存される黄砂バイオエアロゾルの集積培養と系統分類学的解析

概要

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Asian dust which possibly carries microbial particles (KOSA bioaerosol) may impact ecosystems and human health in downwind environments. To confirm the atmospheric transport of microorganisms with KOSA, the KOSA bioaerosol preserved in seasonal snow cover on Mt. Tateyama in Toyama prefecture, Japan, was investigated by means of a culture-amendment technique targeting the halotolerant and oligotrophic bacteria which are known to be tolerant to atmospheric environmental stressors. The snow samples collected from the layers with and without KOSA particles in a 6.60 m deep-snow pit. The samples with KOSA particles indicated microbial growth in the culture media without dilution and with 10-1 dilution and with NaCl up to 10%, while the sample without KOSA particles showed no microbial growth. The phylogenetic analysis using 16S rRNA genes revealed that the members of the genus Bacillus were one of the major groups in the microbial structures. In particular, some species were identified as members of the B. subtilis group, which have been detected from the KOSA mineral particles collected from the atmosphere over KOSA arrival region (Suzu City). Presumably, the halotolerant and oligotrophic bacteria detected in this study were associated with the KOSA particles that descended to the snow cover on Mt. Tateyama.