The Resistance of Drosophila melanogaster to Oxidative, Genotoxic, Proteotoxic, Osmotic Stress, Infection, and Starvation Depends on Age According to the Stress Factor

Abstract

We studied how aging affects the ability of Drosophila melanogaster to tolerate various types of stress factors. Data were obtained on the resistance of D. melanogaster to oxidative and genotoxic (separately paraquat, Fe³⁺, Cu²⁺, and Zn²⁺ ions), proteotoxic (hyperthermia, Cd²⁺ ions), and osmotic (NaCl) stresses, starvation, and infection with the pathological Beauveria bassiana fungus at different ages. In all cases, we observed a strong negative correlation between age and stress tolerance. The largest change in the age-dependent decline in survival occurred under oxidative and osmotic stress. In most experiments, we observed that young Drosophila females have higher stress resistance than males. We checked whether it is possible to accurately assess the biological age of D. melanogaster based on an assessment of stress tolerance. We have proposed a new approach for assessing a biological age of D. melanogaster using a two-parameter survival curve model. For the model, we used an algorithm that evaluated the quality of age prediction for different age and gender groups. The best predictions were obtained for females who were exposed to CdCl₂ and ZnCl₂ with an average error of 0.32 days and 0.36 days, respectively. For males, the best results were observed for paraquat and NaCl with an average error of 0.61 and 0.68 days, respectively. The average accuracy for all stresses in our model was 1.73 days.

Keywords: Drosophila melanogaster; aging; biomarkers of aging; modeling; stress resistance.

Figure 1

Survival curves of D. melanogaster at different ages. The graphs show the change in survival with an increasing age of flies (5, 10, …, 50 days) when exposed to 20 mM paraquat ((a)—males, (b)—females)).

Figure 2

The relationship between the median survival time and the age of flies under the following stress conditions: oxidative and genotoxic stress ((a)—male, (c)—female), proteotoxic, osmotic stress, starvation, and response to infection ((b)—male, (d)—females). The lines mark linear regression: red lines show a strong change in survival, gray—middle, blue—slight.

Figure 3

Results of Cox regression calculation for the D. melanogaster after exposure to different stressors regardless of the sex of the individual. (a)—indicates regression of the risk for flies under the influence of each stressor when the factor is solely the stress, excluding the age of the individual. We have accepted the exposing to paraquat males at the age of 5 days at a basic level. (b)—shows the regression of risk for flies under the influence of each of the stressors, with an estimate of the impact of interacting factors (stressor and age of flies). 1.00 hazard ratio, in this case, means no influences of age on the death risk ratio for each stressor.