Accepted_test
Bacteria and phages are in constant confrontation: the former develop and improve protection systems, the latter develop methods to circumvent them. The study of bacteriophages and bacterial defense systems expanded the understanding of the nature of viral infection, became the basis for establishing the molecular mechanisms of heredity, and also gave and continues to give genetic engineering new effective tools and techniques. The aim of our work was to compare the composition of protective systems in predominantly free-living bacteria and intracellular parasites, as well as to test the defense systems of prokaryotes living in extreme environments.
In obligate intracellular parasites, defense systems were either not detected, or there were not more than four of them per genome. The systems found in them consist of a single protein and can perform third-party functions, which explains the presence of these systems in obligate parasites even after their characteristic genome reduction. Parasites have an average of 2 to 5 defense systems per genome. Such a small variety of parasite defense systems deserves further study. In extremophile bacteria, except for Halobacterium, there is no significant decrease in the number of systems, but their diversity is reduced.
We plan to study a separate type of defense systems, as well as the distribution of bacterial defense systems within a species with different habitats of strains.