パイロシーケンス法によるキトラ古墳石室内の微生物群集構造解析

摘要

キトラ古墳は，奈良県高市郡明日香村の南西部に位置する二段築成の円墳であり，国の特別史跡に指定されている。その石室内の壁画は，2004年の石室の発掘調査後から取り外しが決定され，2008年には側壁の絵画部分や天井の星宿図の取り外し作業が完了し，2010年には，余白漆喰についてもほぼ取り外しが終了した。取り外された壁画については現在，空調管理のされた施設内で保存修復作業が行われている。%Almost all of the plaster walls and ceilings with polychrome mural paintings covering the interior of the stone chamber in the Kitora Tumulus were relocated in 2008, and all of the plaster without paintings were also relocated completely in 2010. Intermittent UV irradiation was applied to control microbes on the remaining plasters from 2009 to 2013. Although significant fungal growth on the plaster was suppressed effectively, continuous monitoring for the changes of the microbial communities under intermittent UV irradiation control inside the stone chamber is still necessary. In the present study, pyrosequencing analysis was performed to monitor current microbial communities on the stone surface. From the result of bacterial community analysis, the genera Jiangella, Promicromonospora and Streptomyces in the phylum "Actinobacteria" were detected in high abundance in some samples. For fungal communities, the genus Farlowiella in the class Dothideomycetes, the genera Mariannaea, Beauver-ia， and Acremonium (Sarocladium-clade) in the class Sordariomycetes, the genus Thelebolus in the class Leotiomycetes, and the genera Phialophora and Exophiala in the class Eurotiomycetes were detected predominantly. Because the stone chamber of the Kitora Tumlus was buried in 2013， it will not be possible to collect more samples for microbial analysis. Basic information obtained from a series of microbiological surveys in the Kitora Tumulus under intermittent UV irradiation will be helpful for future development to conserve other stone chambers and mural paintings.