Drosophila melanogaster larvae detect low doses of UVC radiation as manifested by a writhing response.
Exposure of insects and higher orders of animals to UVC radiation has been shown to result in toxicity with a delayed expression. We have observed an immediate writhing response in slowly wandering third instar larvae of Drosophila melanogaster exposed to UVC radiation at doses that were not lethal. UVB and UVA radiation had no effect. Mutants for the visual and sensory systems appeared to respond normally, but CO(2) anesthesia resulted in reversible inhibition. ebony and silver mutants, which affect different pathways in catecholamine metabolism, showed an absent to reduced response. Using UVC lasers, we were able to demonstrate a response in different regions of the larval body. Furthermore, a 193 nm laser that penetrates only 2-5 micron(s) was able to induce a response but unable to kill the larvae. These results suggest a photochemical reaction occurs in the cuticle which produces free radicals that stimulate the nerves and muscle which are present immediately below the epidermis. Possible targets for the UVC radiation are catecholic compounds secreted and processed into the cuticle of third instar larvae just to pupariation whose primary function is to crosslink the protein and carbohydrate components.
Baden
H P
HP
Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston 02129, USA.
Kollias
N
N
Anderson
R R
RR
Hopkins
T
T
Raftery
L
L
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004331:Drosophila melanogaster / Q000187:drug effects / Q000528:radiation effects*; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D007814:Larva / Q000528:radiation effects; D008297:Male; D008750:Methyldopa / Q000494:pharmacology; D009043:Motor Activity; D010777:Photochemistry; D014466:Ultraviolet Rays
D000975:Antioxidants; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D005609:Free Radicals; D008750:Methyldopa