Application of pseudomurein endoisopeptidase to fluorescence in situ hybridization of methanogens within the family Methanobacteriaceae.
In situ detection of methanogens within the family Methanobacteriaceae is sometimes known to be unsuccessful due to the difficulty in permeability of oligonucleotide probes. Pseudomurein endoisopeptidase (Pei), a lytic enzyme that specifically acts on their cell walls, was applied prior to 16S rRNA-targeting fluorescence in situ hybridization (FISH). For this purpose, pure cultured methanogens within this family, Methanobacterium bryantii, Methanobrevibacter ruminantium, Methanosphaera stadtmanae, and Methanothermobacter thermautotrophicus together with a Methanothermobacter thermautotrophicus-containing syntrophic acetate-oxidizing coculture, endosymbiotic Methanobrevibacter methanogens within an anaerobic ciliate, and an upflow anaerobic sludge blanket (UASB) granule were examined. Even without the Pei treatment, Methanobacterium bryantii and Methanothermobacter thermautotrophicus cells are relatively well hybridized with oligonucleotide probes. However, almost none of the cells of Methanobrevibacter ruminantium, Methanosphaera stadtmanae, cocultured Methanothermobacter thermautotrophicus, and the endosymbiotic methanogens and the cells within UASB granule were hybridized. Pei treatment was able to increase the probe hybridization ratio in every specimen, particularly in the specimen that had shown little hybridization. Interestingly, the hybridizing signal intensity of Methanothermobacter thermautotrophicus cells in coculture with an acetate-oxidizing H(2)-producing syntroph was significantly improved by Pei pretreatment, whereas the probe was well hybridized with the cells of pure culture of the same strain. We found that the difference is attributed to the differences in cell wall thicknesses between the two culture conditions. These results indicate that Pei treatment is effective for FISH analysis of methanogens that show impermeability to the probe.
Nakamura
Kohei
K
Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8566, Japan.
Terada
Takeshi
T
Sekiguchi
Yuji
Y
Shinzato
Naoya
N
Meng
Xian-Ying
XY
Enoki
Miho
M
Kamagata
Yoichi
Y
D000818:Animals; D016798:Ciliophora / Q000254:growth & development / Q000382:microbiology; D003470:Culture Media; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D017013:Methanobacteriaceae / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology
D003470:Culture Media; D012722:Sewage; C051467:peptidoglycan endopeptidase; D010450:Endopeptidases