Daichi Ijiri, Yoshio Nishimura, Ayumi Katafuchi, Saki Shimamoto, Miyu Kamimura, Ichiro Oshima, Namiko Nakamura, Shozo Tomonaga, Shinya Ishinhara, Akira Ohtsuka . Development and Validat2025 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） BACKGROUND: Nτ-methylhistidine released endogenously from muscle into urine is an index of muscle protein breakdown, and part of Nτ-methylhistidine is excreted as the acetylated derivative, N-acetyl-Nτ-methylhistidine. OBJECTIVES: The aim of this study was to measure the urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine. A quantitative method was established using liquid chromatography-tandem mass spectrometry (LC-MS/MS) operated in Q1 single-ion monitoring (SIM) mode and multiple reaction monitoring (MRM) mode with stable-isotope dilution analysis. METHODS: We synthesized N-acetyl-Nτ-methylhistidine and its isotopic analog for stable-isotope dilution analysis. Then, we validated a method for quantifying urinary concentrations of intact Nτ-methylhistidine, N-acetyl-Nτ-methylhistidine, and creatinine to precisely determine their concentrations in rats, humans, cattle, and dogs. Creatinine correction was applied to normalize for urine volume. RESULTS: For both SIM and MRM analysis, the acceptable linear ranges of detection were 5 pmol/mL to 10 nmol/mL with r2 = 1.000 in SIM mode and MRM mode. The LC-MS/MS methods operated in both SIM and MRM transitions detected changes in the urinary excretion levels of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine in response to starvation and refeeding of rats. The methods also detected urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine in cattle, humans, and dogs. CONCLUSIONS: These results suggest that the LC-MS/MS method operated in SIM mode and MRM mode can be used to measure urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine. DOI： 10.1016/j.tjnut.2025.09.024 PubMed
Yoshinao Kume, Mizuki Kamegawa, Miori Shintaku, Ayumi Katafuchi, Saki Shimamoto, Miyu Kamimura, Daichi Kuwahara, Yukiko Osawa, Shinya Ishihara, Akira Ohtsuka, Daichi Ijiri . Effects of2025 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） This study aimed to evaluate the effect of supplementation with Panaferd®-AX, an astaxanthin-rich dried cell powder obtained from the carotenoid-producing bacterium Paracoccus carotinifaciens, on the muscle concentration of carotenoids, fatty acids, free amino acids, and imidazole dipeptides in broiler chickens. Thirty male broiler chickens (Ross 308) were allocated to three groups at 14 days of age. Until 28 days of age, the control group was fed a basal diet; whereas the two test groups were fed a basal diet supplemented with Panaferd®-AX at 0.025% or 0.15%, corresponding to 5 ppm or 30 ppm astaxanthin, respectively. At the end of the experiment, body weight, body weight gain, feed intake, feed conversion rate, and tissue weight did not differ between the groups. Feeding Panaferd®-AX increased muscle astaxanthin, as well as plasma zeaxanthin, and lutein concentrations, but did not affect fatty acid composition. In the pectoralis major muscle, it decreased lipid peroxidation and drip loss; while increasing carnosine content. In summary, Panaferd®-AX increased muscle antioxidant content (i.e., carotenoids and carnosine), which consequently reduced lipid peroxidation and drip loss in the skeletal muscle of broiler chickens. DOI： 10.2141/jpsa.2025027 PubMed
Yui Otani, Mika Kawanishi, Miyu Kamimura, Azusa Sasaki, Yasushi Nakamura, Takako Nakamura, Shigehisa Okamoto . Behavior and possible function of Arabidopsis BES1/BZR1 homolog 2 in brass2022 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） Two key transcription factors (TFs) in brassinosteroid (BR) signaling BRASSINOSTEROID INSENSITIVE 1-EMS-SUPPRESSOR 1 (BES1) and BRASSINAZOLE RESISTANT 1 (BZR1), belong to a small family with four BES1/BZR1 homologs (BEH1-4). To date, in contrast to the wealth of knowledge regarding BES1 and BZR1, little is known about BEH1-4. Here, we show that BEH2 was expressed preferentially in the roots and leaf margins including serrations, which was quite different from another member BEH4, and that BRs downregulated BEH2 through a module containing GSK3-like kinases and BES1/BZR1 TFs, among which BES1, rather than BZR1, contributed to this process. In addition, BEH2 consistently existed in the nucleus, suggesting that its subcellular localization is not under BR-dependent nuclear-cytoplasmic shuttling control. Furthermore, gene ontology analysis on RNA-seq data indicated that BEH2 may be implicated in stress response and photosynthesis. These findings might assist in the future elucidation of the molecular mechanisms underlying BR signaling. DOI： 10.1080/15592324.2022.2084277 PubMed
