Effects induced by keV low-energy ion irradiation in the nematode Caenorhabditis elegans

The nematode Caenorhabditis elegans is an excellent model organism with which to study the biological effects and mechanisms of ionizing irradiation. In this study, using C. elegans as a model, the effects of keV low-energy argon ion irradiation were investigated, by examining cuticle damage, worm survival, brood size, life span, and germ cell death. The surface etching of worm cuticle after ion impact was investigated by trypan blue staining and SEM microscopy. The degree of damage increased with ion fluence (2 x 10(14) to 7 x 10(14) ions cm(-2)) and energy (5-25 keV). The survival rates, as compared to vacuum control, of ion-bombarded worm larvae at different developmental stages (L1-L4) decreased with increasing ion fluence. L1 larvae were found to be more sensitive to ion bombardment than larvae at other stages. The mean brood size in ion-bombarded groups decreased with increasing ion fluence and energy. Furthermore, keV argon ions caused a significant increase in the number of apoptotic germ cells. However, average lifespan was not significantly affected.