9:15 AM - 9:30 AM
[BCG07-02] Discovery of unique microbial streamer communities in a terrestrial hot spring
Keywords:terrestrial hot springs, streamers, microbial dense communities, Deferribacteraceae
Dense microbial biofilm communities (called streamers) are often developed in high-temperature terrestrial hot springs. Despite decades of study worldwide, microbial associations for streamer formation within the communities remain unknown. In this study, we discovered new streamer-forming terrestrial hot springs and characterized the chemical composition of the hot springs, the microbial community structure of the streamers, and performed cultivation experiments to obtain unknown microorganisms to understand the differences from previously reported streamers and the contribution of unknown microorganisms in the high-temperature microbial ecosystems.
The chemical composition of the spring was found to be pH 7, sulfidic, and highly saline, with a maximum temperature of 57.6oC. Microbial compositions were analyzed at three points in the comminutes using amplicon sequences targeting the V4 region in 16S rRNA genes. The analysis revealed that the ecosystem is relatively simple, consisting of a small number of phylogenetic groups. Specifically, the number of Amplicon Sequence Variants (ASVs) with a relative abundance of at least 0.05% was found to be 17 to 25. A dominance of the uncultivated members of the genus Nitratiruptor and Hydrogenophilus and the family Deferribacteraceae composed more than half of the community. After culturing the collected samples at 50oC, we obtained a novel strain that showed 94.0% sequence similarity to the 16S rRNA of Petrothermobacter organivorans ANA strain (Deferribacteraceae).
The streamers analyzed in this study included many uncultivated strains. By clarifying the differences between previously studies, a better understanding of the mechanisms of microbial association for streamer formation can be achieved. Furthermore, the study may shed light on the physiological and ecological roles of uncultivated microorganisms, many of which are still unknown.
The chemical composition of the spring was found to be pH 7, sulfidic, and highly saline, with a maximum temperature of 57.6oC. Microbial compositions were analyzed at three points in the comminutes using amplicon sequences targeting the V4 region in 16S rRNA genes. The analysis revealed that the ecosystem is relatively simple, consisting of a small number of phylogenetic groups. Specifically, the number of Amplicon Sequence Variants (ASVs) with a relative abundance of at least 0.05% was found to be 17 to 25. A dominance of the uncultivated members of the genus Nitratiruptor and Hydrogenophilus and the family Deferribacteraceae composed more than half of the community. After culturing the collected samples at 50oC, we obtained a novel strain that showed 94.0% sequence similarity to the 16S rRNA of Petrothermobacter organivorans ANA strain (Deferribacteraceae).
The streamers analyzed in this study included many uncultivated strains. By clarifying the differences between previously studies, a better understanding of the mechanisms of microbial association for streamer formation can be achieved. Furthermore, the study may shed light on the physiological and ecological roles of uncultivated microorganisms, many of which are still unknown.