Purpose. For use in modern methods of determining the activity of biologically active substances (BAS), in particular, hormones and vitamins that regulate the development of insects and are used in beekeeping and sericulture, and in non-optimal concentrations act as insecticides and are used to combat insect pests and ectoparasites.
Scope. Entomology.
Advantages. The method for determining the activity of a biologically active substance (BAS) improves the method for determining the activity of BAS by simplifying (in comparison with the closest analogue) its implementation and increasing the reliability of the result, in particular, using Drosophila melanogaster, a classic object of genetic research, as an indicator organism.
Description. The method for determining the activity of a biologically active substance (BAS), which involves studying the effect of BAS on the growth of somatic cells of Drosophila melanogaster Meig., is characterized in that first a nutrient medium is prepared with the addition of BAS with a given (experiment) and zero (control) concentrations, then on the prepared nutrient solution. At the end of the 3rd stage of development, salivary glands are isolated from the larvae, from which crushed acetoorcein preparations of polytene chromosomes are prepared, after which the percentage distribution of nuclei with different degrees of chromosome polyteny (SPH) is determined on these preparations, differentiated by chromosome width. SPH and the difference between the average values of SPH in the experiment and the control are used to judge the activity of the biologically active substance.