[Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].

Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants.

[Electron microscopy and restriction analysis of bacteriophages isolated from quince and pear with symptoms of fire blight].

Phage populations of isolates from quince and pear affected with fire blight disease were studied using electron microscopy, restriction analysis and both agarose gel electrophoresis of particles and host range scoping method. The isolate from quince (pMA1) comprises at least three phage populations and two phage variants that can be detected on different bacterial indicators. After titration of this isolate on Erwinia amylovora the bacteriophage KEY of B1 morphotype with the genome size of 82.4 kb was identified. The isolate pMA1 also includes a unique phage population 4*, which can be identified on the test bacteria Pantoea agglomerans (Pag) g150. Two analogous populations being also present in the isolate pMA1 that appeared to be close phage variants with almost identical Hpal-restriction patterns can be identified using Pag g157 and 9/7-1. The situation is similar in the case of phage isolates from pear, pMG. Three phage populations identified in it using three different indicators represent the same phage of C1 morphotype (TT10-27) with a genome size of 71.4 kb. At least two other phage populations were also detected in the same isolate using P. agglomerans 9/7-2 as an indicator. A model system allowing the most efficient analysis of the isolates for the presence of different phage populations and phage variants in plants infected by fire blight disease has been developed. It provides for using three indicator enterobacterial species closely associated with the plants: E. amylovora, Erwinia "horticola" and Pagglomerans and ignoring of the phage cloning procedure.

Plasmid profile, colicinogeny and phage sensitivity as indicators of the dynamics of Escherichia coli populations in the human gut.

A possibility to use such bacterial phenotypes as plasmid profiles, colicinogeny and phage sensitivity as dynamics indicators of enterobacterial population in the human intestine was considered in the present work. All these three phenotypes, considered together with the type of enterobacterial association and age of the patients may reflect the dynamic state of the individual E. coli population that is currently prevailing in the intestinal microflora. The data on plasmid profile structure, colicinogeny and phage sensitivity indicate to considerable quantitative and qualitative diversity of E. coli genetic elements and the intensive interaction between bacteria in the human gut. This diversity is reflected on the formation of the dynamic population of intestinal bacteria, which obviously depends on the host age. The evaluation of the three above mentioned phenotypes confirmed that the E. coli isolates are closely coordinating with other members of the intestinal microbial association. It is noted that the plasmid frequency increases, the colicin range expands and phage sensitivity decreases in E. coli cells simultaneously with the increase of the number of enterobacterial species in the gut. The dynamics of changes in the biological features was observed among E. coli strains from different age groups of patients. The most significant was high frequency of colicinogenic strains in adult patients and di-associated E. coli containing one large plasmid in the youngest patients with dysbiosis.

Long-term preservation of unstable bacteriophages of enterobacteria.

Bacteriophages are integral components of bacterial communities. Their practical applications and significance for humans are various. Thus, keeping phage collections along with their specific host bacteria is an urgent and important mission for biologists. The problems of the long-term storage of phages steel are not completely solved. The main difficulties may occur due to the structural instability of virions as well as an accelerated genetic variability in phage genomes both in vivo and in vitro. In the paper the results of 10-years observation over unstable bacteriophage storage process was presented as well the method of their long-term preservation was proposed. It consisted of the optimization of STMG buffer system (200 mM NaCl, 10 mM Tris-HCl, pH 7.4, 1 mM MgCl, 100 microg/ml gelatin) [Serwer P, Pichler ME. Electrophoresis of bacteroiphage T7 capsids in agarose gels//J. Virol. - 1978 - V28, N3. - P.917-928] by higher gelatin concentration or its replacement by ficoll (2 - 6%), and increasing of Mg(2-) concentration to 10 mM. The proposed buffer composition allowed saving structural entirety of unstable phage virions during their long-term storage.

Characteristics of defective phage particles of Pectobacterium carotovorum ZM1.

It is shown for the first time that the expression products of defective prophages are typical of defective lysogenic systems of phytopathogenic Pectobacterium carotovorum. It is established that virus-like particles (LP) such as phage capsids are packing bacterial DNA which size is determined by pulse field gel electrophoresis separation. Based on data about capsid structures which are formed by the virulent mutant ZF40/421, there is made a suggestion about the forming mechanism of defective virions of P carotovorum.

[Structural stability of DNA of the transposon derivatives of pCA25 plasmid].

Mutants of Erwinia carotovora subsp. carotovra 48A carrying plasmid pCA25 and its transposon variant and resistant to mitomycin C, nalidixic acid and streptomycin were used in the research. It has been shown that the presence of transposon in plasmid pCA25 (strain 48A-7/4b[pCA25::Tn9]) does not practically affect the frequency of appearance of the stable bacterial mutants under the effect of all three antibiotics. Several variants, the plasmid profile of which differs from the initial one were found only in the case of this strain clones resistant to mitomycin C. Electrophoretic mobility of the plasmid DNA of the mutant clones 31 and 32 decreased and approached mobility of the initial plasmid pCA25, the mutant plasmid 13 had high electrophoretic mobility compared to pCA25::Tn9. Some plasmids are the deletion variants of pCA25::Tn9, one of two IS1-elements of the transposon Tn9 being absent in them. The obtained results indicate that the studied plasmid pCA25 is stable, is not eliminated from the cells under different treatments and confirm once more the hypothesis of the prophage origin of the plasmid. The paper is presented in Russian.

[Peculiarities of morphogenetical development of erwiniophage ZF40 virulent mutants ].

The distortion of morphopoiesis or tail attachment to the capsid is a characteristic feature of morphogenetical development not only of a reproductive infection but also of the lysogenic induction of the defective bacteriophage Erwinia carotovora subsp. carotovora (Ecc). A model system for studying morphogenetical development and assembling of the virion was created on the basis of the phage ZF40 and its two virulent mutants ZF40-421 and ZF40(5/5), as well as the indicator culture Ecc M2-4/50 R1 being nontraditional host for these phages. It has helped to establish that the diameter of the phage capsid is not a conservative value. The presence of capsids of two types with the average diameters 60.3 and 65.0 nm is characteristic of the virmutant ZF40c(5/5)/50RI, while in the course of morphogenesis the phage ZF40-421/50RI forms only one type of heads of 65 nm in size. These heads are probably not firmly connected to the tails since the degree of the secondary destruction of the virions of the phage Zf40-421/50RI is considerably higher, than that of the virions of the phage ZF40c(5/5)/50RI. The number of capsids being 60.3 nm in diameter prevails considerably in the latter. The both virulent mutants as a whole are essentially more stable than their isogenic partners obtained on Ecc RC5297 which helps to make a conclusion about considerable influence of specific bacterial proteins of the host-cell on morphogenesis and morphopoiesis.

[Using the laboratory strains of Escherichia coli for studying colicinogenicity].

The indicator system which includes laboratory strains of Escherichia coli K12, K12-C600, BE, and C-Ia is offered for studying colicinogenicity. It has helped to establish that 32 of 100 patients with dysbacterioses of colon carry a colicin-producing strain of E. coli. A tendency is discovered to the increase of occurrence of colicinogenic strains of escherichias with patients' age. Only 24% of E. coli strains form active colicins in a group of one-year old children. Frequency of colicinogenic strains occurrence increases to 33 and 42 %, respectively, in teenagers and adult patients. A strict decrease of total activity of colicins is the main peculiarity of polymicrobe associations in which the prevailing strain of E. coli is accompanied by 3-5 strains of other enterobacteria. As to their sensitivity of colicins the indicator strains are arranged in the following order: K12-C600 (84%), KR (69%), BE (63%) and C-Ia (47%). In spite of that, the low-sensitive strains can be effective for identification of very specific colicins. Since the laboratory strains of E. coli K12, BE and C-Ia are the hosts for specific bacteriophages of E. coli, the indicator system on their basis may be useful for studying the interrelation between colicins and coliphages, as well as plasmids and restriction-modification systems. The paper is presented in Russian.

[Abortive infection in Erwinia carotovora, as a source of nanoparticles of phage nature].

A possibility to obtain nanoparticles of phage nature using abortive phage infection was shown for the first time. It was found out that the nonspecific host Erwinia carotovora subsp. carotovora J2 being infected by phage ZF 40-RT80, the cells form a 100-fold surplus of capsid structures. Using the electron microscope the authors have found two types of phage capsids which differ from each other and have different modal diameters--47.5 and 71.5 nm. The found capsids pack the phage DNA which releases them under treatment of the preparations by DNAse I. A simple method of purification of capsid structures from mature virions which are formed in inconsiderable quantity in the process of abortive phage infection is proposed. The obtained results create preconditions for obtaining capsid nanoparticles as well as for studying the stages of morphogenesis and morphopoiesis of phage ZF40 without attracting special phage mutants.

[Streptomyces globisporus 1912 mutants highly sensitive to ultraviolet radiation, their antibiotic activity and reparation ability].

Twenty five mutants defective in biosynthesis of antitumor antibiotic landomycin E and 22 mutants with higher level biosynthesis of this antibiotic were obtained after nitrosoguanidine mutagenic treatment of wild strain of Streptomyces globisporus 1912 spores. Six of them (5 mutants of LndE and 1 mutant of LndE+) were found to carry uvs-mutation responsible for high level UV-sensitivity. Uvs-mutants 1912-11 and 1912-16 were highly sensitive to the action of nitrous acid, hydrogen peroxide and methyl-methane-sulfonate.

[Functional organization of prophage and lysogeny in Erwinia carotovora with participation of a temperate bacteriophage ZF40].

Functional organization of a prophage of the temperate bacteriophage ZF40 of Erwinia carotovora subsp. carotovora which includes its immunity and inducibility as well as its effect on the host phenotype. It was established that the prophage ZF40 forms several different states in E. carotovora which are distinguished by the indices of spontaneous and lysogenic induction. In contrast to other prophages, including the lambdoid ones, the prophage ZF40 is capable to establish cytoplasmic overimmunity which protects the lysogenic system from superinfection by virulent mutants or other homoimmune bacteriophages. An increase of sensitivity of ZF40-lysogens to killing activity of colicino-like carotovoricin (CCTV) and destabilization of defective lysogeny, or resistant MCTV-prophages are related to the phenomenon of the phage lysogenic conversion of E. carotovora.

[Indicator system for studying the lysogenic development of temperate bacteriophage ZF40 Erwinia carotovora].

The indicatory system for studying the lysogenic development of the moderate erwiniophage ZF40 has been created on the basis of the data on the efficiency of inoculation, adsorption of phage particles on a cell, and cooperation between different clear-mutants. The use of the indicatory strains RC5297 and 62A-dl. Derivatives of Erwinia carotovora subsp. carotovora 62A, permitted dividing c-mutants of the phage ZF40 into two types which, in their turn, include 4 groups of complementation (cooperation). An original method has been developed to identify mutants defective in terms of synthesis of the phage repressor. Prerequisites were created for genetic mapping of C-region of the phage ZF40.