The purpose of this study is to examine the effect of microwaves on germ cells of Drosophila me lanogaster. 1) The materials used were 72-hour old larvae, late third instar larvae, young pupae, and old pupae. The microwaves were applied for five seconds, 10 seconds, and 30 seconds using household electronic range (2.45GHz) with an output power of 200W (Fig. 1). We thus attemped to observe the chromosomal aberrations of meiotic division and to do a somatic protein syntheses analysis of sibling adult flies. 2) In this study, cytological preparations were made by the air-drying method (Tonomura and Shima, 1986) or by the squash method (H. Kayano and A. Kayano, 1987). 3) The primary electrophoresis method was used for the biological analysis protein synthesis by SDG-PAGE on sibling adult bodies and old pupae. We conducted are study by using more than 690 microphotographs of germ cells of 20 females and 20 males taken from each group and exposed to microwaves at various lengths of time to see whether or not cell division had taken place. No abnormal chromosomes were found in larvae exposed to microwaves in the current experiment. However, metaphase polyploidy (?) was found in the first spermatocyte of flies which emerged from young pupa that had been exposed to microwaves for 30 seconds (Fig. 4a). We have also observed chromosomal aberrations in the first spermatocyte and secondary spermatocyte for the 10-second-exposure group of pupae immediately before the emergence (Fig. 4b and c). No chromosomal aberrations were found in the control group (Fig. 5a-c). Electrophoresis using polyacrylamide gel (density; 12 gel) was performed for a biochemical study of protein synthesis in these exposed groups. No abnormalities were found to result from the electrophoresis in male and female flies which had been exposed while they were larvae. However, a loss of protein bands in the molecular-weight region of near 100K dalton was found in flies of the 10-second-exposure group or that had been exposed while they were young pupae or

in old pupae immediately before emergence. This is assumed to be caused by the lack of high-polymer proteins (Fig. 6).