Analysis of light pulse induced phase shift locomotor activity rhythms in vg and cry^b mutants of Drosophila melanogaster

Abstract

Circadian rhythms are governed by endogenous oscillators (clocks) in a wide variety of organisms can be phase shifted (i.e., delayed or advanced) by brief exposure to light and changes in temperature. The present study was to determine the influence of single light pulse (~ 100 lux; 15 minutes) at four circadian time points (CT 00, CT 06, CT 12 and CT 18) in wild type (WT; Oregon R+); and vestigial (vg) and cryptochrome depleted (cry^b) mutants of Drosophila melanogaster (fruit fly) under constant darkness (DD) condition. Single light pulse in vg and cry^b mutants showed significant (p<0.05) phase shift of the free running circadian locomotor rhythms under these circadian time points as compared to WT flies. From this study, we suggest that blue-light component cryptochrome as well as wing structure play an important role for free-running circadian rhythms in D. melanogaster and single light pulse effectively alters the phase of free-running circadian rhythms in vg and cry^b mutants at these circadian time points.