- 著者
- Yuga Hirakata Mamoru Oshiki Kyohei Kuroda Masashi Hatamoto Kengo Kubota Takashi Yamaguchi Hideki Harada Nobuo Araki
- 出版者
- 日本微生物生態学会 / 日本土壌微生物学会 / Taiwan Society of Microbial Ecology / 植物微生物研究会
- 雑誌
- Microbes and Environments (ISSN:13426311)
- 巻号頁・発行日
- pp.ME16067, (Released:2016-07-12)
- 被引用文献数
- 22
Predation by protists is top-down pressure that regulates prokaryotic abundance, community function, structure, and diversity in natural and artificial ecosystems. Although the effects of predation by protists have been studied in aerobic ecosystems, they are poorly understood in anoxic environments. We herein studied the influence of predation by Metopus and Caenomorpha ciliates—ciliates frequently found in anoxic ecosystems—on prokaryotic community function, structure, and diversity. Metopus and Caenomorpha ciliates were cocultivated with prokaryotic assemblages (i.e., anaerobic granular sludge) in an up-flow anaerobic sludge blanket (UASB) reactor for 171 d. Predation by these ciliates increased the methanogenic activities of granular sludge, which constituted 155% of those found in a UASB reactor without the ciliates (i.e., control reactor). Sequencing of 16S rRNA gene amplicons using Illumina MiSeq revealed that the prokaryotic community in the UASB reactor with the ciliates was more diverse than that in the control reactor; 2,885–3,190 and 2,387–2,426 operational taxonomic units (>97% sequence similarities), respectively. The effects of predation by protists in anaerobic engineered systems have mostly been overlooked, and our results show that the influence of predation by protists needs to be examined and considered in the future for a better understanding of prokaryotic community structure and function.
- 著者
- Yuga Hirakata Mamoru Oshiki Kyohei Kuroda Masashi Hatamoto Kengo Kubota Takashi Yamaguchi Hideki Harada Nobuo Araki
- 出版者
- Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology
- 雑誌
- Microbes and Environments (ISSN:13426311)
- 巻号頁・発行日
- vol.30, no.4, pp.335-338, 2015 (Released:2015-12-22)
- 参考文献数
- 22
- 被引用文献数
- 11 23
The aim of the present study was to investigate the prokaryotic community structure of the anaerobic ciliate, Metopus sp. using rRNA sequencing, fluorescence in situ hybridization (FISH), and transmission electron microscopy (TEM). Metopus sp. was physically separated from anaerobic granular sludge in a domestic wastewater treatment plant and anoxically cultivated for 7 d. 16S rRNA gene sequences from the prokaryotes Methanoregula boonei and Clostridium aminobutyricum were abundantly detected in Metopus ciliates. The FISH analysis using the oligonucleotide probes Mg1200b and Cla568 demonstrated that these prokaryotes were localized within Metopus cells. These results identify M. boonei- and C. aminobutyricum-like prokaryotes as novel endosymbionts of Metopus ciliates.