It is known that inbreeding leads to homozygotization of alleles of the most genes. The rate of this process is determined by the degree of kinship between crossed individuals. In addition, inbred breeding is accompanied by a change in the structure and functioning of the genome of cells of females’ generative system: mutational level increases and oogenetic segregation may be violated. This leads to a decrease in the number of laid eggs and an increase in the level of embryonic mortality. This process, described as "the effect of resistance to selection," is aimed at adapting to external conditions and associated with the selection of viable offspring. The character of manifestations of mutational variability is determined to a large extent by the direction of selection. However, up to now our knowledge of the role of the genotype in controlling the level of embryonic mortality in Drosophila melanogaster stocks in conditions of inbred breeding is not deep enough. The purpose of our work was to analyze the frequency of dominant lethal mutations in Drosophila stocks from radiation-contaminated regions of Ukraine (Polesskoe and Ozero), carrying radius incompletus mutation, depending on the degree of inbreeding. It is shown that under conditions of severe inbreeding (without selection) changes in the total frequency of dominant lethal mutations have a cyclic character, which depends on the genotype of the stocks. So, in radius incompletus stock, the indicator studied increases after 10 generations of selection and remains at enough high level for 20 generations. For the stocks from radiation-contaminated territories of Ukraine with radius incompletus mutation, which are contrasting in the level of embryonic mortality, two decrease peaks are shown (for the stock ri(Oz) – after 5 and 65 generations of inbreeding) and an increase (for the line ri(Pol) – after 5 and 32 generations of inbreeding) of the total frequency of dominant lethal mutations. The main factor influencing the change in the mortality level at the stage of early embryogenesis in Drosophila carrying radius incompletus mutation is the genotype of the stocks that are used in the work. It’s contribution increases after 10 (h2gen=44.78), 15 (h2gen=45.86) and 100 (h2gen=46.36) generations of inbreeding. The effect of inbred breeding was observed after 32 (h2inbr=22.61) and 65 (h2inbr=11.89) generations. The combined effect of both factors on the total frequency of dominant lethal mutations is shown for each of the generations studied. The highest values were shown after the 5th (h2comb=53.86) and the 65th (h2comb =40.63) generations of inbred breeding.

Inhibition of inflammatory processes in the model organisms using non-steroidal anti-inflammatory drugs (NSAIDs) can be an effective geroprotective method. The mechanisms of NSAIDs action in insects have not been studied enough. It is assumed that they are similar to those in mammals and are based on the inhibition of cyclooxygenase 2, which leads to a decrease in the synthesis of prostaglandins. Prostaglandins are central signaling molecules for mediated coordinated cellular immunity of insects and control the imago eclosion, egg production and oogenesis of Drosophila. Obviously, signaling pathways exist where the role of prostaglandins has not yet been shown. In our work, the resistance to starvation of Drosophila melanogaster of wild type stock Canton-S under pharmacological inhibition of prostaglandin metabolism at different stages of ontogenesis was analyzed. In the experiments, nimesulide was used in three different concentrations – 0.1, 0.05, and 0.025 mg/ml. The results of the experiments have shown, that the development of larvae in the medium containing NSAID nimesulide leads to a decrease in resistance to stress factor – starvation on average by 19.2% in females and by 7.4% in males. Resistance to starvation of the most stress-resistant (10% of individuals with the longest life span) females decreases during the development of larvae in the medium containing nimesulide in concentrations 0.1 and 0.05 mg/ml. The consumption of nimesulide by imago at a concentration of 0.025 mg/ml during the first days of life increases stress resistance and life span at starvation in females by 12.4% and in males in all variants of the experiment on average by 17.8%. Under the same experimental conditions, life span during starvation increased in the most stress-resistant females Canton-S. Thus, pharmacological inhibition of prostaglandin metabolism leads to an increase of resistance to starvation if virgin adults are exposed to nimesulide during the first day after eclosion, and stress resistance decreases if nimesulide is consumed by larvae. This is obviously, due to that somatic tissues of the adult flies are almost entirely composed of postmitotic cells, while intensive processes of cell division are characteristic of growing larvae. The data obtained indicate that the action of nimesulide on postmitotic imago cells promotes transition of cells to increased stress tolerance, while the impact on actively dividing cells of larvae leads to a decrease in the resistance of the adults.