Lysogeny

Lysogeny, joint survival of bacteria and bacteriophages, in which the bacteriophage is part of normally developing bacterial cells. If lysogeny nucleic acid bacteriophage is included in the chromosomes bacteria and played with it. Proteins are made, giving the bacteria-host a number of new features, such as changing its virulence, sensitivity to antibiotics or other bacteriophages. Phage particles are formed. Cm. also Bacteriophage, Genetics (microorganisms).

Lysogeny (from the Greek. lysis - decay, destruction and gennao - create, produce) - inheritable property bacterial cells to form infectious bacteriophage and highlight it in the environment. Bacterial culture, with this property, called lishennyj.
The phenomenon of lysogeny opened Lviv (A. Lwoff) and Gutmann (A. Gutmann), which showed that individual cells You. B. megaterium share repeatedly without allocation of phage, but after the 19th division subsidiary bacterium lidiruet, while highlighting the active fag (see Bacteriophage). Discover active phage or phage antigens inside lysogeny bacteria have not succeeded. It is established that in lysogeny bacteria bacteriophage is a special form that is different from the Mature phage. This form that Lviv was named propaga, is a phage DNA, combined with the bacterial DNA. Thus, the state of lysogeny is an example of merging the genetic apparatus of the virus (PAH) with the chromosome of the host (bacteria).
Proper non-pathogenic bacterial cells and reprodutseerida simultaneously with bacterial chromosome. Lethal to bacteria is only the transformation of propaga in Mature phage. The ability to cause the state of lysogeny in bacteria specific, so-called moderate, phages. The infection is bacterial cells in such a phage, culminating in the establishment of the state of lysogeny, called reductive, unlike productive ending reproduction phage and lysis of cells. Lithogenetic acquired by the bacteria in infected moderate phage,is very resistant property, continuing for many years. However, the possible reversal lysogenic cells to elisageannette.
Temperate phages, lithogenesis bacterium, combined with her chromosome, usually in certain areas. For example, the phage λ localized to chromosome E. coli K12 near a gene that controls the splitting of galactose and phage 080 coupled with the genes of tryptophan synthesis. Lysogeny bacteria acquire immunity to re-infection homologous phage. It is proved that this form of immunity cells caused by the inability of DNA SUPERAntiSpyware phage to induce in the cell synthesis, leading to the formation of phage DNA and proteins.
The transformation of propaga in vegetative, and then in Mature phage is called induction. This process can occur spontaneously or under the influence of external factors, of which the most active is ultraviolet irradiation. The mechanism of induction is not yet exactly understood, but it is known that as a result of its chromosome phage is Autonomous, not associated with the bacterial chromosomes, and the cell begins synthesis of phage particles. Of particular interest is the fact that the majority of inducing agents is mutagens (see Mutation), and many of them carcinogens (see Carcinogenic substances). In some cases, lithogenicity bacteria is accompanied by change (conversion) of some of its properties. For example, described moderate diphtheria phages, lithogenicity which causes the appearance of diphtheria bacilli of toksighennosti.
Cm. also, Genetics of bacteria, viruses.