Microbial cells are constantly threatened by invasion of foreign genetic elements. There are many mobile genetic elements (MGEs), including viruses, plasmids, transposons, etc., that invade them. Such selective pressure provoked the production of various defense systems in bacteria and other microorganisms, such as restriction–modification, abortive infection, exclusion of phage superinfection, toxin–antitoxin modules, argonaute proteins, and adaptive immune response. In this paper, we will consider the adaptive immunity systems of bacteria and archaea (CRISPR-Cas), their complex organization and functioning, the data on their origin associated with a new class of transposons, self-replicating casposons and other MGEs, and their role in the regulation of virulence genes and other important bacterial functions, as well as data on production in MGE systems that oppose adaptive immunity.

微生物细胞不断受到外来遗传因素入侵的威胁。有许多移动遗传元件（MGEs）侵入它们，包括病毒、质粒、转座子等。这种选择压力激发了细菌和其他微生物中各种防御系统的产生，例如限制性修饰、流产感染、噬菌体重复感染排除、毒素-抗毒素模块、argonaute 蛋白和适应性免疫反应。在本文中，我们将考虑细菌和古细菌 (CRISPR-Cas) 的适应性免疫系统、它们复杂的组织和功能、与一类新的转座子、自我复制卡座子和其他 MGEs 相关的起源数据，以及它们在毒力基因和其他重要细菌功能的调节中的作用，