RESEARCH ARTICLE Life span alteration after irradiation in Drosophila melanogaster strains with mutations of Hsf and Hsps A. Moskalev Æ M. Shaposhnikov Æ E. Turysheva Received: 2 March 2008 / Accepted: 6 May 2008 / Published online: 13 June 2008 Ó Springer Science+Business Media B.V. 2008 Abstract The life span alteration after c-irradiation and/or paraquat treatment in Drosophila in wild type strain Canton-S and strains with mutations of heat shock factor (1–4 alleles) and heat shock proteins (Hsp70Ba 304 , Hsp83 e6A , Hsp22 EY09909 , Hsp67Bb EY099099 ) was investi- gated. Chronic low-dose rate c-irradiation (0.017 and 0.17 cGy/h) on pre-imago stages was used as a priming dose (absorbed doses were 4 and 40 cGy). Paraquat, a free radical inducing agent, was a challenging factor (20 mM for 1 day). It was shown that chronic irradiation led to adaptive response in both sexes except homozy- gous males and females with mutations of Hsf 4 and Hsp70Ba 304 . The gender-specific differences in stress response were discovered in wild type strain Canton-S, Hsp22 EY09909 Hsp67Bb EY09909 homozygotes and Hsp83 e6A heterozygotes: the adaptive response persisted in males, but not in females. Thus, Drosophila Hsp and Hsf mutation homozygotes did not demonstrate the adaptive response in the majority of cases, implying an important role of those genes in radiation hormesis and adaptation to stresses. Keywords Adaptive response Á Drosophila Á Heat shock proteins Á Life span Á Low doses Introduction Practically all living organisms (from bacteria to mammals) are able to quickly respond and adapt to various external stresses. The phenomenon when a cell or an organism, after it had been exposed to low doses of stressors, exhibits increased tolerance to a damaging action is referred to as ‘‘hormesis’’. This effect is induced by various damages including alkylating agents, heat and oxidative stress, ionizing radiation, heavy metals, hypergravity (Crawford and Davies 1994; Le Bourg et al. 2002; Le Bourg 2007; Sorensen et al. 2007). The main biological sense of such adaptive response is to protect the cells and organisms from high doses of dangerous factors (ionizing radiation, mutagens, and extreme temperature). When studying chromosome aberrations of human lymphocytes after irradiation Wolf et al. discovered the phenomenon of ‘‘radioadaptive response’’ (Olivieri et al. 1984). Later on, the existence of adaptive response was confirmed in in vitro and in vivo experiments with the use of different endpoints, such as cell lethality, chromosome aberrations, point mutations and DNA repair. Radioadaptive response was recorded in response to both low LET (linear energy transfer) (X-rays and c-irradiation) and high LET ionizing radiation (neutrons, a-particles). Prim- ing dose ranges usually from 0.01 to 0.5 Gy at dose rate 0.01–1.0 Gy/min. The lower time limit for the adaptive response to form following priming A. Moskalev (&) Á M. Shaposhnikov Á E. Turysheva Department of Radioecology, Institute of Biology, Komi Science Center, Ural Division of Russian Academy of Sciences, Kommunisticheskaja St. 28, Syktyvkar 167982, Russia e-mail: amoskalev@list.ru 123 Biogerontology (2009) 10:3–11 DOI 10.1007/s10522-008-9147-5