LEVELS OF CARBOHYDRATES IN SHORT-LIVED STRAIN OF Drosophila melanogaster

Abstract

Aim. The aim of this study was to investigate the concentrations of key energetic substrates such as glucose, fructose, and trehalose, in control and artificially selected flies shown to have shorter lifespan. Methods. For all experiments flies were maintained on standard yeast-sucrose nutrient medium consisted of 5% sucrose, 5% yeast, 1% agar and 0.18% nipagin as mold growth inhibitor. Experimental line of flies was selected on high-protein diet and previously showed short lifespan. Newly enclosed flies were kept two days for mating and used for measurement of feeding behavior and fecundity. Some flies were frozen at -80 °C for further analysis. Concentrations of glucose, fructose and trehalose were measured by Gas Chromatography/Mass Spectrometry using described protocol and expressed per wet weight. Results. Amount of glucose was significantly higher in experimental flies of both sexes. Male flies had about 70% more free glucose and females for about 45%. These differences were accompanied with higher amounts of trehalose that consist of two molecules of glucose and is a form of glucose storage in Drosophila. Trehalose content in experimental males was 2-fold higher, while in females it was higher for about 1.8-fold. Fructose content was also higher in experimental flies. This carbohydrate is metabolized through glycolysis, providing energy in the form of ATP. Beyond energy production, fructose plays a role in supporting reproductive processes such as oogenesis in females, though measure of fecundity showed no difference. Conclusions. Our results show that despite similar consumption of food and reproduction offspring of artificially selected flies have shorter lifespan. However, this effect can be explained by lower energetic status while flies store more energetic substrates such as glucose, fructose and trehalose.