Abstract
To illuminate the functions of larval hemocytes in the silkworm, Bombyx mori, heavy ion beams (12C5+, 50Gy) were used to locally irradiate the right and left thoracic regions where the imaginal wing disks are located and to which are attached the hemopoietic organs at the 4th instar premolting stage. As well, changes of hemocyte density (total hemocyte count per mm3) were examined and protein components in the hemolymph were analyzed by SDS-polyacrylamide gel electrophoresis and immunoblotting during the 5th instar.
The locally irradiated larvae grew well, pupated, and then became adult moths in a normal manner, despite the destruction of their hemopoietic organs. However, hemocyte densities in the irradiated silkworms were found to be significantly lower than those of the control during the middle and late stages of the 5th instar. Moreover, a few components of hemolymph proteins were affected by localized irradiation: increased amounts of storage proteins were detected at day 0 of the 5th instar, while a protein band (about 24kDa) was weakly detected at day 0 to day 2, then disappeared in the 5th instar. Similar effects were also observed in the larvae generally irradiated with heavy ion beams. Changes of the hemolymph proteins after irradiation are considered to be associated with functions of circulating hemocytes.
