Isorhamnetin Promotes 53BP1 Recruitment through the Enhancement of ATM Phosphorylation and Protects Mice from Radiation Gastrointestinal Syndrome

Flavonoids are a subclass of polyphenols which are attractive, due to possessing various physiological activities, including a radioprotective effect. Tumor suppressor p53 is a primary regulator in the radiation response and is involved in the pathogenesis of radiation injuries. In this study, we revealed that isorhamnetin inhibited radiation cell death, and investigated its action mechanism focusing on DNA damage response. Although isorhamnetin moderated p53 activity, it promoted phosphorylation of ataxia telangiectasia mutated (ATM) and enhanced 53BP1 recruitment in irradiated cells. The radioprotective effect of isorhamnetin was not observed in the presence of ATM inhibitor, indicating that its protective effect was dependent on ATM. Furthermore, isorhamnetin-treated mice survived gastrointestinal death caused by a lethal dose of abdominal irradiation. These findings suggested that isorhamnetin enhances the ATM-dependent DNA repair process, which is presumably associated with the suppressive effect against GI syndrome

Taxonomy of Mesopelagic Fishes Collected around the Ogasawara Islands by the T/S Oshoro-Maru

A taxonomic examination of 3,108 specimens of mesopelagic fishes, collected around the Ogasawara Islands in December 2010 by a beam trawl net operated from the T/S Oshoro-maru, Hokkaido University, Japan, resulted in the recognition of 99 species representing 34 families and 65 genera. Descriptions are provided for all species, two of them〔 a stomiid Eustomias braueri Zugmayer, 1911 and linophrynid Haplophryne mollis (Brauer, 1902)〕 being new records for Japan.　Three species, a stomiid Eustomias sp., trachipterid Desmodema sp. and oneirodid Oneirodes sp., could not be identified at the species leve