環境微生物の培養性とその生態学的意義

抄録

It is common knowledge in microbial ecology that most microorganisms in nature are not recovered on standard culture media. Therefore, although microbiologists are still making efforts to isolate unknown microorganisms, culture-independent molecular approaches to the analysis of microbial diversity are essential in this research area. High-throughput next-generation sequencing (NGS) is accelerating the growth of microbial ecology and phylogenetics strategies based on genomic and metagenomic information. In light of the current status of this research, we need to reconsider the significance of bacteria isolated as colony-forming units from the environment. One of the major foci regarding the culturability of bacteria is their ecological importance as “rare biospheres” of complex microbial communities. Another area of interest in culturable bacteria in the environment is whether their phylotypes can be covered completely by NGS-aided amplicon analyses. This paper focuses on the extent to which NGS and clone library approaches and conventional culture methods share the numbers of operational taxonomic units of environmentally derived bacteria. Biases in cultureindependent molecular approaches are also discussed on the basis of comparative data on 16S rRNA gene amplicons and respiratory quinone as biomarkers.