title: Post-eclosion decline in 'knock-down' thermal resistance and reduced effect of heat hardening in Drosophila melanogaster.
abstract: 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.
authors.affiliation: Department of Biological and Biomedical Sciences, University of Durham, Durham City, DH1 3LE, UK.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Pappas
authors.forename: David
authors.initials: D
authors.lastname: Hyde
authors.forename: Ken
authors.initials: K
authors.lastname: Bowler
authors.forename: Volker
authors.initials: V
authors.lastname: Loeschcke
authors.forename: Jesper G
authors.initials: JG
authors.lastname: Sørensen
mesh_terms: 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
chemical_list: D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins