Meeting Abstract
P3.30 Tuesday, Jan. 6 Critical periods for oxygen effects on adult size in Drosophila melanogaster HEINRICH, Erica C.*; HARRISON, John F.; Arizona State University erica.heinrich@asu.edu
In many organisms, including humans, lowered oxygen concentrations have been seen to have an effect on development and adult size. In previous studies, it has been shown that flies reared in hypoxia are significantly smaller than those reared in normoxia. However, the mechanism which creates this size effect remains unknown. If oxyen effects on size occur during a specific developmental stage, this would narrow down the possible pathways responsible for the oxygen effect on size. Prior studies have suggested that the pupal phase may be critical for oxygen effects on body size in fruitflies. We examined this question by rearing flies in normoxia (21% oxygen) except for specific 24 hour time periods when atmospheric oxygen level was changed to 10% oxygen. We also conducted the converse experiment. We hypothesized that the late larval would be particularly oxygen-sensitive as that is when most mass is gained, and that the early pupariation stage would also be very sensitive as this is when the adult cuticle is formed. However, fly size was significantly affected by oxygen (by about 6%) no matter at what point during development that the atmospheric oxygen was switched, including the egg stage. Therefore, either there are multiple independent mechanisms by which oxygen affects size (e.g. suppression of feeding during the larval stage, effects on cuticle cell size in the pupal stage) or there is a developmental pathway mediating oxygen effects on size available at all times during development . The effects of egg oxygen level on adult size are particularly intriguing, as they suggest that oxygen effects on the embryo organ and body sizes of adults This research was supported in part by funds from the ASU School of Life Sciences and the Howard Hughes Medical Institute through the Undergraduate Science Education Program and by NSF IBN 0419704 to JFH.
