anhydrobiosis-associated nuclear dna damage and repair in the sleeping chironomid linkage with radioresistanceanhydrobiosis-associated核dna损伤与修复的睡眠和抗辐射性chironomid链接.pdfVIP

Anhydrobiosis-Associated Nuclear DNA Damage and Repair in the Sleeping Chironomid: Linkage with Radioresistance 1,2. 1.¤ 2 2 1 Oleg Gusev , Yuichi Nakahara , Veronica Vanyagina , Ludmila Malutina , Richard Cornette , 3 4 1 3 1 Tetsuya Sakashita , Nobuyuki Hamada , Takahiro Kikawada , Yasuhiko Kobayashi , Takashi Okuda * 1 Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Japan, 2 Department of Invertebrate Zoology, Kazan State University, Kazan, Russia, 3 Microbeam Radiation Biology Group, Japan Atomic Energy Agency, Takasaki, Japan, 4 Nuclear Technology Research Laboratory, Radiation Safety Research Center, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan Abstract Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae had restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated larvae after anhydrobiosis were similar to those of hydrated larvae irradiated with 70 Gy of high-line