Argulus coregoni (Branchiura: Argulidae) parasitic on the torrent catfish Liobagrus reini in Japan

An adult male of the argulid branchiuran Argulus coregonis Thorell, 1864 was collected from the body surface of a torrent catfish Liobagrus reinii Hilgendorf, 1878 (Siluriformes: Amblycipitidae) in the Aga River, a tributary of the Agano River, Fukushima Prefecture, central Honshu, Japan. This is the first record of A. coregoni infecting the amblycipitid fish as well as a new host record for the species. This collection also extends the distributional range of A. coregoni from Tochigi Prefecture northward to Fukushima Prefecture and is the first record of the species in the Tohoku Region of Japan

Bilirubin is produced nonenzymatically in plants to maintain chloroplast redox status

血液の分解産物ビリルビンが植物で作られることを発見 --植物の効率的な光合成に寄与している可能性--. 京都大学プレスリリース. 2023-06-08.Bilirubin, a potent antioxidant, is a product of heme catabolism in heterotrophs. Heterotrophs mitigate oxidative stress resulting from free heme by catabolism into bilirubin via biliverdin. Although plants also convert heme to biliverdin, they are generally thought to be incapable of producing bilirubin because they lack biliverdin reductase, the enzyme responsible for bilirubin biosynthesis in heterotrophs. Here, we demonstrate that bilirubin is produced in plant chloroplasts. Live-cell imaging using the bilirubin-dependent fluorescent protein UnaG revealed that bilirubin accumulated in chloroplasts. In vitro, bilirubin was produced nonenzymatically through a reaction between biliverdin and reduced form of nicotinamide adenine dinucleotide phosphate at concentrations comparable to those in chloroplasts. In addition, increased bilirubin production led to lower reactive oxygen species levels in chloroplasts. Our data refute the generally accepted pathway of heme degradation in plants and suggest that bilirubin contributes to the maintenance of redox status in chloroplasts

イチジクモザイクウイルスのタンパク質機能に関する細胞生物学的研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 難波 成任, 東京大学教授 柴田 道夫, 東京大学准教授 勝間 進, 東京大学特任准教授 藤本 優, 東京大学准教授 山次 康幸University of Tokyo(東京大学