Zabuga O. The effect of dietary restriction during development on fitness and life span of drosophila melanogaster

The dissertation is focused on the changes in life span and fitness of Drosophila melanogaster that are resulted by the dietary restriction implemented during development. There is shown that the larvae reared in the culture medium that contained food components under the concentration of 60% had the significant increase in the duration of their development. The larvae reared in the culture medium with the food components' concentrations of 10% and 20% had the increase in their mortality. The flies reared in the culture medium with the minimal concentration of food components have been characterised with the decrease in their average body weight. There has been recorded the increase in the resistance to a complete food deprivation in the males developed in the culture medium that contained 50% of food components compared to the control. There hasn't been detected the same effect in the female flies. The females aged of 7, 15 and 21 days that have been reared in the culture medium with the food components' concentration of 50% had their fertility reduced compared to the control. At the same time, those female flies showed no significant differences in the mean and maximum life span compared to the control population. In contrast the dietary restriction significantly effected on the life expectancy of the males. Thus the male flies developed in the culture medium that contained 50% and 60% of food components had the increase in the average life span for 11%. The results of the research confirm the "mismatch hypothesis". Thus if flies have been developed in the 100% culture medium but being adult have been maintained with the dietary restriction, they have the almost three fold decrease in the average life span. In the contrary, when flies have been maintained in the conserve restricted diet conditions throughout all their ontogenesis they demonstrated the significant increase in the average life expectancy. There have been indicated that only mothers' (nor fathers') complete food deprivation before mating and fertilization had led to the increase in the lives of their female descendants. Such an effect hadn't been detected in the male descendants. The development in the culture medium that contained 20% of food components there resulted into the increase in the transcription levels of a dSir2 and an InR genes compared to the control. The significant increase in the InR expression has been detected only in the adult males reared in the dietary restriction but not in the females. In the male flies the 50% dietary restriction implemented during the development resulted into the increase in SOD activity in the age of 15 and 20 days as well as catalase activity at the 15 day of life. Also there has been demonstrated the reduction in the AGEs' accumulation in both male and female D. melanogaster that reared in the culture medium that contained 50% of food components. It can be assumed that identified at the molecular and biochemical level changes are explained by the long-term epigenetic modifications that occur as a result of dietary restriction at the stage of development and lead to the increase in the life span of the male D. melanogaster.