- Naito, Yuichi, Morita, Ayako, Natsuhara, Kazumi, Tadokoro, Kiyoshi, Baba, Jun, Odani, Shingo, Tomitsuka, Eriko, Igai, Katsura, Tsutaya, Takumi, Yoneda, Minoru, Greenhill, Andrew, Horwood, Paul, Soli, Kevin, Phuanukoonnon, Suparat, Siba, Peter, Umezaki, Masahiro
- Authors: Naito, Yuichi , Morita, Ayako , Natsuhara, Kazumi , Tadokoro, Kiyoshi , Baba, Jun , Odani, Shingo , Tomitsuka, Eriko , Igai, Katsura , Tsutaya, Takumi , Yoneda, Minoru , Greenhill, Andrew , Horwood, Paul , Soli, Kevin , Phuanukoonnon, Suparat , Siba, Peter , Umezaki, Masahiro
- Date: 2015
- Type: Text , Journal article
- Relation: American Journal of Physical Anthropology Vol. 158, no. 3 (2015), p. 359-370
- Full Text: false
- Reviewed:
- Description: Objectives: We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ15NHair-Diet: δ15NHair - δ15NDiet) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ15N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ15N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ15N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants. Materials and Methods: These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ15N was estimated by comparing hair δ15N values to mean dietary δ15N values calculated from the recorded intake of each food item and their δ15N values. Results: The results showed that: i) there was a significant difference in Δ15N among study locations (3.9±0.9‰ for most urbanized, 5.2±1.0‰ for medium and 5.0±0.9‰ for least urbanized communities; range=1.2-7.3‰ for all participants); and ii) estimated Δ15N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range=0.9-7.6%). Discussion: We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ15N values of the participants. Am J Phys Anthropol 158:359-370, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
Nitrogen fixation and nifH diversity in human gut microbiota
- Igai, Katsura, Itakura, Manabu, Nishijima, Suguru, Tsurumaru, Hirohito, Suda, Wataru, Tsutaya, Takumi, Tomitsuka, Eriko, Tadokoro, Kiyoshi, Baba, Jun, Odani, Shingo, Natsuhara, Kazumi, Morita, Ayako, Yoneda, Minoru, Greenhill, Andrew, Horwood, Paul, Inoue, Jun-ichi, Ohkuma, Moriya, Hongoh, Yuichi, Yamamoto, Taro, Siba, Peter, Hattori, Masahira, Minamisawa, Kiwamu, Umezaki, Masahiro
- Authors: Igai, Katsura , Itakura, Manabu , Nishijima, Suguru , Tsurumaru, Hirohito , Suda, Wataru , Tsutaya, Takumi , Tomitsuka, Eriko , Tadokoro, Kiyoshi , Baba, Jun , Odani, Shingo , Natsuhara, Kazumi , Morita, Ayako , Yoneda, Minoru , Greenhill, Andrew , Horwood, Paul , Inoue, Jun-ichi , Ohkuma, Moriya , Hongoh, Yuichi , Yamamoto, Taro , Siba, Peter , Hattori, Masahira , Minamisawa, Kiwamu , Umezaki, Masahiro
- Date: 2016
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 6, no. (2016), p. 1-11
- Full Text:
- Reviewed:
- Description: It has been hypothesized that nitrogen fixation occurs in the human gut. However, whether the gut microbiota truly has this potential remains unclear. We investigated the nitrogen-fixing activity and diversity of the nitrogenase reductase (NifH) genes in the faecal microbiota of humans, focusing on Papua New Guinean and Japanese individuals with low to high habitual nitrogen intake. A 15 N 2 incorporation assay showed significant enrichment of 15 N in all faecal samples, irrespective of the host nitrogen intake, which was also supported by an acetylene reduction assay. The fixed nitrogen corresponded to 0.01% of the standard nitrogen requirement for humans, although our data implied that the contribution in the gut in vivo might be higher than this value. The nifH genes recovered in cloning and metagenomic analyses were classified in two clusters: one comprising sequences almost identical to Klebsiella sequences and the other related to sequences of Clostridiales members. These results are consistent with an analysis of databases of faecal metagenomes from other human populations. Collectively, the human gut microbiota has a potential for nitrogen fixation, which may be attributable to Klebsiella and Clostridiales strains, although no evidence was found that the nitrogen-fixing activity substantially contributes to the host nitrogen balance. © The Author(s) 2016.
- Authors: Igai, Katsura , Itakura, Manabu , Nishijima, Suguru , Tsurumaru, Hirohito , Suda, Wataru , Tsutaya, Takumi , Tomitsuka, Eriko , Tadokoro, Kiyoshi , Baba, Jun , Odani, Shingo , Natsuhara, Kazumi , Morita, Ayako , Yoneda, Minoru , Greenhill, Andrew , Horwood, Paul , Inoue, Jun-ichi , Ohkuma, Moriya , Hongoh, Yuichi , Yamamoto, Taro , Siba, Peter , Hattori, Masahira , Minamisawa, Kiwamu , Umezaki, Masahiro
- Date: 2016
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 6, no. (2016), p. 1-11
- Full Text:
- Reviewed:
- Description: It has been hypothesized that nitrogen fixation occurs in the human gut. However, whether the gut microbiota truly has this potential remains unclear. We investigated the nitrogen-fixing activity and diversity of the nitrogenase reductase (NifH) genes in the faecal microbiota of humans, focusing on Papua New Guinean and Japanese individuals with low to high habitual nitrogen intake. A 15 N 2 incorporation assay showed significant enrichment of 15 N in all faecal samples, irrespective of the host nitrogen intake, which was also supported by an acetylene reduction assay. The fixed nitrogen corresponded to 0.01% of the standard nitrogen requirement for humans, although our data implied that the contribution in the gut in vivo might be higher than this value. The nifH genes recovered in cloning and metagenomic analyses were classified in two clusters: one comprising sequences almost identical to Klebsiella sequences and the other related to sequences of Clostridiales members. These results are consistent with an analysis of databases of faecal metagenomes from other human populations. Collectively, the human gut microbiota has a potential for nitrogen fixation, which may be attributable to Klebsiella and Clostridiales strains, although no evidence was found that the nitrogen-fixing activity substantially contributes to the host nitrogen balance. © The Author(s) 2016.
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