ИСТИНА

Bacteriophages – viruses of bacteria widely spread in the world. Some authors estimate total quantity of bacteriophages in the biospherе as approximately 1031 and about 108 of different genotypes [1]. Natural bacteriophage community - is an immense pool of genetic diversity which has not been studied yet. It has been shown that lytic bacteriophages may play a fundamental role in cycling nutrients and organic matter in sea water [2]. Also, viruses provide genetic exchange between communities [3,4]. It has been shown for 4 different exotoxins encoded by prophages that phage infection in soil, seawater and seabed sediments contributes to the spread of pathogenic strains of microorganisms and the emergence of new pathogenic forms [4]. One of the most relevant examples of genetic adaptation (following Lamark‘s mechanism - the inheritance of acquired features) are recently discovered systems of bacteria immunity to the mobile elements such as plasmids and bacteriophages - the so-called CRISPR/Cas system. CRISPR/Cas systems were found in the genomes of vast majority of eubacteria and archaea [5]. Horizontal gene transfer carried out by bacteriophages and plasmids, plays an important role in the cell‘s life. For example, it provides a common resistance factor to various antibiotics among the pathogenic bacteria. It was shown that many bacterial toxins (virulence factors) are encoded by prophages, such as botulinum toxin C1 and G (Clostridium botulinum), Diphtheria toxin (Corynebacterium diphtheriae), Shiga toxin (Escherichia coli), streptococcal toxin produced by the causative agent of scarlet fever (Streptococcus pyogenes), and some others. [6]. Thus, bacteriophages provide an important factor in genetic exchange and evolution of bacteria, get involved in the formation of biofilms, and participate in the pathological process in some bacterial infections. Any changes in the ability of foreign DNA to penetrate of into bacterial cells have a direct influence on the genetic adaptability of prokaryote. Нumic acids (HA) in soil can be one of the factors of such alterations. А lot of researchers report on the role of humic substances in interaction with various chemical toxicants on microorganisms [7,8,9], but evidences of their interaction with „living systems“ including bacteriophage, is still lacking. We have previously shown that a lot of soil bacteria adsorb HA on the surface, with different intensity and quantity [10]. Some researchers, who studied the behavior of bacteria and bacteriophages in lakes with a high content of organic matter, assumed that humic substances were able to bind bacteriophages directly in water [11]. Other researchers demonstrated that HA prevented the sorption of phageson at the surface of mineral particles [12]. In this work we aimed to measure the adsorption rate of bacteriophages to host cells coated with HA, according to the classical method [13], as well as to study of the role of free HA in the binding of phages in solution.