Post-eclosion decline in 'knock-down' thermal resistance and reduced effect of heat hardening in Drosophila melanogaster.
The dependency of knock-down resistance on age, from 0 to 12 days post eclosion, was studied in two lines of Drosophila melanogaster, one selected for knock-down resistance and one unselected control. Additionally, the inducible Hsp70 expression level was assessed at maintenance temperature and after a heat hardening treatment (1 h at 35 degrees C) at the same ages. Knock-down resistance decreased roughly linearly with age in both control and knock-down selected lines and in both sexes regardless of maintenance temperature. Hsp70 expression, however, fell only from day 0 to day 3 and was thereafter changed little. Acclimation did not result in detectable difference between lines. The effect of hardening was only significant for control flies. This suggests that the increased knock-down resistance of the selected line was reached at the expense of hardening ability.
Pappas
Cassandra
C
Department of Biological and Biomedical Sciences, University of Durham, Durham City, DH1 3LE, UK.
Hyde
David
D
Bowler
Ken
K
Loeschcke
Volker
V
Sørensen
Jesper G
JG
D000064:Acclimatization / Q000502:physiology*; D000375:Aging; D000818:Animals; D029721:Drosophila Proteins / Q000096:biosynthesis; D004331:Drosophila melanogaster / Q000502:physiology*; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature; D008297:Male
D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins