Stress specific correlated responses in fat content, Hsp70 and dopamine levels in Drosophila melanogaster selected for resistance to environmental stress

• Published in: Journal of insect physiology Vol. 55; no. 8; pp. 700 - 706
• Main Authors: Sørensen, J.G., Vermeulen, C.J., Flik, G., Loeschcke, V.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2009
• Subjects: adaptation; Animals; body fat; correlated responses; Cross resistance; Dopamine; Dopamine - metabolism; Drosophila melanogaster; Drosophila melanogaster - genetics; Drosophila melanogaster - physiology; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Fat content; Fats - metabolism; Female; fruit flies; Gene Expression; gene expression regulation; genotype; heat shock proteins; Hsp70; HSP70 Heat-Shock Proteins - genetics; HSP70 Heat-Shock Proteins - metabolism; insect proteins; lipid content; locomotion; Motor Activity; neurotransmitters; phenotype; quantitative traits; Stress resistance; stress tolerance; Stress, Physiological; Fat content; Hsp70; Cross resistance; Dopamine; Stress resistance
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2009.05.002

Studies of adaptation to stressful environments have frequently encountered cross resistance. This has prompted the hypothesis that certain adaptations confer resistance to multiple stressors. Some of the genes and mechanisms conferring stress resistance have been identified, however, the generality and basis of stress adaptation and cross resistance is still unclear. We investigated several physiological traits that have been previously linked to increased stress resistance: Hsp70 expression, fat content and dopamine levels. Additionally, we studied a behavioural trait, locomotor activity, as a proxy for the physiological state of the organisms. Physiology is the mechanistic link between resistance phenotype and underlying genetic background, and provides insights into the background and generality of cross resistance and correlated responses to selection for stress resistance. We assessed the relationship between the measured traits and stress resistance in a set of lines selected for increased resistance to several environmental stressors. We found that, although all physiological traits displayed significant differentiation among selection regimes, none were consistently associated with increased general stress resistance. This demonstrates that directional changes in Hsp70 expression level, dopamine level and fat content occur in response to the specific requirements of the different stress regimes, rather than as a general response to stress.