Extreme tolerance of Paramecium to acute injury induced by γ rays

Due to the wide use of nuclear energy, nuclear radiation threat is increasing day by day. However, methods for protection against nuclear radiation are limited and not effective. Therefore, it is necessary to develop an effective method for protection and therapy against injury caused by radiation. According to the law of biological evolution, one of the most primitive eukaryotes, Paramecium , could be tolerant to ionizing radiations, in a way similar to or better than Ramazzottius varieornatus and Bdelloids rotifer . Therefore, in the present study, the anti-radiation effects of Paramecium were explored, which could be applicable to human beings. Paramecium was found to be tolerant to 60 Co γ rays, and its half lethal dose (LD50) was approximately 3000 Gy, which is 60 times more than that of human beings. The GSPATT00021409001 and GSPATT00016349001 genes were significantly up-regulated, which might play a role in DNA binding and nuclear transport, and thus, could function in DNA protection or repair. The biological function of the two genes and their effects in humans need to be explored in future studies.