Koki Kanahama
Tohoku University
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Publication
Featured researches published by Koki Kanahama.
Journal of Plant Physiology | 2010
Kazuhisa Kato; Koki Kanahama; Yoshinori Kanayama
Nitrogenase activity, as acetylene-reduction activity (ARA), in Lotus root nodules was clearly inhibited 27h after the addition of nitrate. Nitric oxide (NO) production was detected at that time in nitrate-supplied root nodules using the NO-reactive fluorescent probe diaminofluorescein-2 diacetate. The involvement of NO production in the inhibition of nitrogenase activity by nitrate was investigated using the NO donor sodium nitroprusside (SNP) and the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO). SNP inhibited ARA at 1mM, and c-PTIO suppressed the inhibition of ARA by nitrate. These results suggest that NO is involved in the inhibition of nitrogenase activity by nitrate in Lotus root nodules.
Journal of Experimental Botany | 2012
Seedahmed A Mohammed; Sogo Nishio; Hideyuki Takahashi; Katsuhiro Shiratake; Hiroki Ikeda; Koki Kanahama; Yoshinori Kanayama
cDNA corresponding to two type-I vacuolar H+-inorganic pyrophosphatases (V-PPases) (SlVP1, SlVP2) and one type-II V-PPase (SlVP3) was isolated from tomato fruit to investigate their role in fruit development. Southern analysis revealed that type-I V-PPase genes form a multigene family, whereas there is only one type-II V-PPase gene in the tomato genome. Although SlVP1 and SlVP2 were differentially expressed in leaves and mature fruit, the highest levels of both SlVP1 and SlVP2 mRNA were observed in fruit at 2–4 days after anthesis. The expression pattern of type-II SlVP3 was similar to that of SlVP2, and the highest levels of SlVP3 mRNA were also observed in fruit at 2–4 days after anthesis, thus suggesting that SlVP3 plays a role in early fruit development. Because SlVP1 and SlVP2 mRNA was more abundant than SlVP3 mRNA, expression of type-I V-PPases was analysed further. Type-I V-PPase mRNA was localized in ovules and their vicinities and in vascular tissue at an early stage of fruit development. Tomato RNAi lines in which the expression of type-I V-PPase genes was repressed using the fruit-specific promoter TPRP-F1 exhibited fruit growth retardation at an early stage of development. Although the major function of V-PPases in fruit has been believed to be the accumulation of materials such as sugars and organic acids in the vacuole during cell expansion and ripening, these results show that specific localization of V-PPase mRNA induced by pollination has a novel role in the cell division stage.
Phytochemistry | 2014
Yoshinori Kanayama; Ryosuke Mizutani; Shino Yaguchi; Ayano Hojo; Hiroki Ikeda; Manabu Nishiyama; Koki Kanahama
The aldo-keto reductase (AKR) superfamily is a large enzyme group of NADP-dependent oxidoreductases with numerous roles in metabolism, but many members in this superfamily remain uncharacterized. Here, PpAKR1, which was cloned from the rosaceous peach tree (Prunus persica), was investigated as a member of the superfamily. While PpAKR1 had amino acids that are important in AKRs and which belonged to the AKR4 group, PpAKR1 did not seem to belong to any of the AKR4 subgroups. PpAKR1 mRNA abundance increased with abscisic acid, oxidative stress, and cold and salt stress treatments in peach. NADP-dependent polyol dehydrogenase activity was increased in Arabidopsis thaliana transformed with PpAKR1. Salt tolerance increased in Arabidopsis transformed with PpAKR1. PpAKR1, which was a previously uncharacterized member of the AKR superfamily, could be involved in the abiotic stress tolerance.
Phytochemistry | 2005
Kazuhiro Ohta; Ryo Moriguchi; Koki Kanahama; Shohei Yamaki; Yoshinori Kanayama
Tohoku journal of agricultural research | 2003
Manabu Nishiyama; Wataru Ohkawa; Koki Kanahama
Scientia Horticulturae | 2012
Ai Uozumi; Hiroki Ikeda; Masahiro Hiraga; Hitoshi Kanno; Masami Nanzyo; Manabu Nishiyama; Koki Kanahama; Yoshinori Kanayama
Journal of The Japanese Society for Horticultural Science | 2005
Yoshinori Kanayama; Maki Kogawa; Masami Yamaguchi; Koki Kanahama
Plant Cell and Environment | 2006
Michihito Deguchi; Alan B. Bennett; Shohei Yamaki; Kunio Yamada; Koki Kanahama; Yoshinori Kanayama
Plant Science | 2005
Kazuhisa Kato; Kazuhiro Ohta; Yoshiko Komata; Takahiro Araki; Koki Kanahama; Yoshinori Kanayama
Journal of The Japanese Society for Horticultural Science | 2002
Tadahisa Yoshimura; Manabu Nishiyama; Koki Kanahama