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영어

In this study, we propose a new screening method based on differences in metabolism between microorganisms. The novel stains obtained in this way provide information about cultivation of uncultured microorganisms.
The key to isolating slow-growing microorganisms from a complex community is eliminating the fast-growing microorganisms. We found that the growth of fast-growing microorganisms could be suppressed by adding phosphate transport inhibitors, fosfomycin or fosmidomycin, to the medium. When microorganisms from the Damupo-seawater were incubated decreasing the amount of phosphate concentration of Marine Media (Difco), the viable cell count decreased by about 33%. In the presence of fosfomycin viable cells decreased markedly and the death rate was 90% and 99% at 5 and 10 mM, respectively. In the case of fosmidomycin, the death rate was 88% at 5 mM. We confirmed that 13 strains of fosfomycin-resistant cells and 20 strains of fosmidomycinresistant cells showed 16S rDNA sequence similarity less than 98% to known database entries. The screening system presented in this work was found to be excellent for searching unculturable microorganisms.