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GC/C/IRMS Chikaraishi, Y., Takano, Y., Ogawa, N.O., and Ohkouchi, N. (2010) Instrumental optimization for compound-specific nitrogen isotope analysis of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry. Earth, Life, and Isotopes (Ohkouchi N., Tayasu I, and Koba, K. Eds), pp. 367-386. Kyoto University Press. Chikaraishi, Y., Ogawa, N.O., Kashiyama, Y., Takano, Y., Suga, H., Tomitani, A., Miyashita, H., and Ohkouchi, N. (2009) Determination of aquatic food-web structure based on compound-specific nitrogen isotopic composition of amino acids. Limnology and Oceanography: Methods., 7, 740-750. Chikaraishi, Y., Kashiyama, Y., Ogawa, N.O., Kitazato, H., and Ohkouchi, N.O. (2007) Biosynthetic and metabolic controls of nitrogen isotopic composition of amino acids in marine macroalgae and gastropods: implications for aquatic food web studies. Marine Ecology Progress Series, 342, 85-90. Ohkouchi, N., Chikaraishi, Y., Close, H., Fry, B., Larsen, T., Madigan, D.J., McCarthy, M.D., McMahon, K.W., Nagata, T., Naito, Y.I., Ogawa, N.O., Popp, B.N., Steffan, S.A., Takano, Y., Tayasu, I., Wyatt, A., Yamaguchi, Y.T. and Yokoyama, Y. (2017) Advances in the application of amino acid nitrogen isotopic analysis in ecological and biogeochemical studies. Organic Geochemistry, 113, 150-174. Ishikawa, N.F., Chikaraishi, Y., Takano, Y., Sasaki, Y., Takizawa, Y., Tsuchiya, M., Tayasu, I., Nagata, T. and Ohkouchi, N. (2018) A new analytical method for determination of the nitrogen isotopic composition of methionine: its application to aquatic ecosystems with mixed resources. Limnology and Oceanography: Methods, 16, 607-620. D-, L- Takano, Y., Chikaraishi, Y., and Ohkouchi, N. (2010) Enantiomer-specific isotope analysis (ESIA) of D- and L-alanine: nitrogen isotopic heteroand homogeneity by microbial and chemical processes. Earth, Life, and Isotopes, (Ohkouchi N., Tayasu I, and Koba, K. Eds), pp. 387-402. Kyoto University Press. Takano, Y., Chikaraishi, Y., Ogawa, N.O., Kitazato, H., and Ohkouchi, N. (2009) Compound-specific nitrogen isotope analysis of D-alanine, L- alanine, and valine: application of diastereomer separation to d15n and microbial peptidoglycan studies. Analytical Chemistry, 81, 394-399. Bassez, M-P., Takano, Y., and Ohkouchi, N. (2009) Organic analysis of peridotite rocks from Ashadze and Logatchev hydrothermal sites. International Journal of Molecular Sciences, 10, 2986-2998. Naito, Y.I., Honch, N.V., Chikaraishi, Y., Ohkouchi, N., and Yoneda, M. (2010) Quantitative evaluation of marine protein contribution in ancient diets based on nitrogen isotope ratios of individual amino acids in bone collagen: an investigation at the Kitakogane Jomon site. American Journal of Physical Anthropology, 143, 31-40. Naito, Y.I., Chikaraishi, Y., Ohkouchi, N., Mukai, H., Shibata, Y., Honch, N.V., Dodo, Y., Ishida, H., Amano, T., Ono, H., and Yoneda, M. Dietary reconstruction of the Okhotsk culture of Hokkaido, Japan, based on nitrogen composition of amino acids: implications for correction of 14 C marine reservoir effects on human bones. Radiocarbon, 52, 671-681. Chikaraishi, Y., Ogawa, N.O., and Ohkouchi, N. (2010) Further evaluation of the trophic level estimation based on nitrogen isotopic composition of amino acids. Earth, Life, and Isotopes, (Ohkouchi N., Tayasu I, and Koba, K. Eds), pp. 37-51. Kyoto University Press. Chikaraishi, Y., Steffan, S., Takano, Y., and Ohkouchi, N. (2015) Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate. Ecology and Evolution, 5, 2048-2059. Steffan, S.A., Chikaraishi, Y., Currie, C.R., Horn, H., Gaines-Day, H.R., Pauli, J.N., Zalapa, J.E., and Ohkouchi, N. (2015) Microbes are trophic analogs of animals. Proceedings of the National Academy of Sciences of the United States of America, 112, 15119-15124. Chan, H.S., Chikaraishi, Y., Takano, Y., Ogawa, N.O. and Ohkouchi, N.(2016) Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios. Earth, Planets and Space, 68: 7. doi:10.1186/s40623-016-0382-8 Yamaguchi, T.Y., Chikaraishi, Y., Takano, Y., Ogawa, N.O., Imachi, H., Yokoyama, Y. and Ohkouchi, N. (2017) Fractionation of nitrogen isotopes during amino acid metabolism in heterotrophic and chemoautotrophic microbes across Eukarya, Bacteria, and Archaea: Effects of nitrogen sources and metabolic pathways. Organic Geochemistry, 111, 101-112. Takizawa, Y., Dharampal, S.P., Steffan, S.A., Takano, Y., Ohkouchi, N. and Chikaraishi, Y. (2017) Intra-trophic isotopic discrimination of 15 N/ 14 N for amino acids in autotrophs: implications for nitrogen dynamics in ecological studies. Ecology and Evolution, 7, 2916-2924. 2010. p15-35.,,,, (2010). (Geochemistry), 44, 233-241. (in Japanese with English abstract),,,,, (2011). Researches in Organic Geochemistry, 27, 3-11. (in Japanese with English abstract)

GC/MS,, 2009 GC/MS []. Researches in Organic Geochemistry, 25, 61-70. (in Japanese with English abstract),, (2016) / GC/MS []. Researches in Organic Geochemistry, 32, 1-18. (in Japanese with English abstract) Chikaraishi, Y. and Ohkouchi, N. (2010) An improved method for precise determination of carbon isotopic composition of amino acids. Earth, Life, and Isotopes, (Ohkouchi N., Tayasu I, and Koba, K. Eds), pp. 355-366. Kyoto University Press. Takano, Y., Chikaraishi, Y., Imachi, H., Miyairi, Y., Ogawa, N.O., Kaneko, M., Yokoyama, Y., Krueger, M. and Ohkouchi, N. (2018) Insight into anaerobic methanotrophy from 13 C/ 12 C- amino acids and 14 C/ 12 C-ANME cells in seafloor microbial ecology. Scientific Reports, 8:14070. doi: 10.1038/s41598-018-31004-5.