Shuhei Takemoto

Publications (2)2.43 Total impact

• Article: Combined analyses of bacterial, fungal and nematode communities in andosolic agricultural soils in Japan.

  Zhihua Bao, Yoko Ikunaga, Yuko Matsushita, Sho Morimoto, Yuko Takada-Hoshino, Hiroaki Okada, Hirosuke Oba, Shuhei Takemoto, Shigeru Niwa, Kentaro Ohigashi, Chika Suzuki, Kazunari Nagaoka, Makoto Takenaka, Yasufumi Urashima, Hiroyuki Sekiguchi, Atsuhiko Kushida, Koki Toyota, Masanori Saito, Seiya Tsushima
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  ABSTRACT: We simultaneously examined the bacteria, fungi and nematode communities in Andosols from four agro-geographical sites in Japan using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and statistical analyses to test the effects of environmental factors including soil properties on these communities depending on geographical sites. Statistical analyses such as Principal component analysis (PCA) and Redundancy analysis (RDA) revealed that the compositions of the three soil biota communities were strongly affected by geographical sites, which were in turn strongly associated with soil characteristics such as total C (TC), total N (TN), C/N ratio and annual mean soil temperature (ST). In particular, the TC, TN and C/N ratio had stronger effects on bacterial and fungal communities than on the nematode community. Additionally, two-way cluster analysis using the combined DGGE profile also indicated that all soil samples were classified into four clusters corresponding to the four sites, showing high site specificity of soil samples, and all DNA bands were classified into four clusters, showing the coexistence of specific DGGE bands of bacteria, fungi and nematodes in Andosol fields. The results of this study suggest that geography relative to soil properties has a simultaneous impact on soil microbial and nematode community compositions. This is the first combined profile analysis of bacteria, fungi and nematodes at different sites with agricultural Andosols.
  Microbes and Environments 01/2012; 27(1):72-9. · 1.91 Impact Factor
• Article: Effect of Storage Temperature on Soil Nematode Community Structures as Revealed by PCR-DGGE.

  Shuhei Takemoto, Shigeru Niwa, Hiroaki Okada
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  ABSTRACT: The optimal duration and conditions for storage of soils collected for nematode community analyses are unknown. To study this issue, three types of soils with different geographical origins from the subarctic to cool-temperate Japan were kept at three temperature levels (5, 10, and 20(°)C) for up to 8 wk following collection. During the storage period, nematode population density was measured, and community structure was assessed by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). No significant changes in the population density or diversity of nematodes (Shannon-Wiener Diversity Index) were observed during storage compared to initial states, except that density in an andosol collected from Tsukuba, Central Japan decreased significantly after 28 d of storage at 5(°)C. However, a regression analysis showed a declining trend in nematode density in the latter half of the storage period when soils were stored at 5 or 20(°)C, depending on the geographic origin of the soil. These results indicate that soils can be stored for 14 d at 5-20(°)C, with 10(°)C as optimal. This is the first study to experimentally determine the optimal preservation conditions for nematode assemblages in soils that are to be analyzed using PCR-DGGE.
  Journal of nematology 12/2010; 42(4):324-31. · 0.52 Impact Factor