Isolation of hitherto-uncultivated microorganisms- Application of radical scavengers

• Published in: Journal of general and applied microbiology Vol. 70; no. 2; p. 2024.02.002
• Main Author: Takahashi, Yōko
• Format: Journal Article
• Language: English
• Published: Japan Applied Microbiology, Molecular and Cellular Biosciences Research Foundation 01.01.2024; Japan Science and Technology Agency
• Subjects: Actinobacteria; Agar; agar medium; Ascorbic acid; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Catalase; Colonies; Colony Count, Microbial; Culture Media - chemistry; DNA, Bacterial - genetics; Free Radical Scavengers; Genera; hitherto-uncultivated microorganism; Hydrogen peroxide; Microorganisms; New taxa; Patulibacter; Phylogeny; Polymerase Chain Reaction; radical scavenger; Reactive oxygen species; Reactive Oxygen Species - metabolism; RNA, Ribosomal, 16S - genetics; Rutin; Scavengers; Soil Microbiology; Soil microorganisms; Strains (organisms); Superoxide dismutase; Superoxide Dismutase - genetics; Superoxide Dismutase - metabolism; actinobacteria; agar medium; hitherto-uncultivated microorganism; radical scavenger; Patulibacter; reactive oxygen species
• ISSN: 0022-1260; 1349-8037
• DOI: 10.2323/jgam.2024.02.002

The culture filtrates of the predominant bacterial strains isolated from soil samples have been shown to increase the microbial colony counts on agar plates used for the isolation of uncultured bacteria. One of the factors in the culture filtrates responsible for this increase was identified to be superoxide dismutase (SOD). The generation of reactive oxygen species (O2-, H2O2, and ・OH) was detected from conventional laboratory agar media. The use of agar media supplemented with radical scavengers (SOD, catalase, ascorbic acid, or rutin) effectively increased the colony counts and kinds of microbial strains that grew from soil samples. Taxonomical studies on these isolates revealed new taxa for phylum Actinomycetota; one family, three genera, and nine species were newly described. One of the strains, Patulibacter minatonensis KV-614T belonging to the new family Patulibacteraceae, was isolated on agar medium supplemented with SOD. P. minatonensis KV-614T represents a novel lineage within the phylum Actinomycetota. A polymerase chain reaction (PCR) study using specific primers for the detection of strains related to the genus Patulibacter, order Solirubrobacterales, showed a high distribution frequency, with detection in over 70% of the soil samples tested. These data suggest that the use of radical scavengers may facilitate the isolation of some hitherto-uncultivated microorganisms widely distributed in soil.