[Dissociation of Pectobacterium carotovorum subsp. carotovorumrelated to the changes in the cell wall lipopolysaccharide].

It is shown for the first time that population heterogeneity of Pectobacterium carotovorum subsp. carotovorum is applicable to a wide range of strains and therefore is a universal characteristic. Using the method of specific selection with the help of carotovoricins which are identical to the phage tails a set of population dissociants of different types was obtained, due to the fact that S-LPS is the part of the cell wall which contains their attachment sites. It was determined that changes in S-lipopolysaccharides lead to the formation of SR-, R-forms of P. carotovorum. A suggestion is made that the changes in the surface structures of dissociants have a significant impact on secretion types II and III--the main pathogenicity factor of some bacteria. The results presented are a prerequisite for studying the direction, the reasons for dissociation process and its impact on the pathogenicity of P. carotovorum.

[Polypeptide content and HPLC-chromatography of the virions of phage ZF40 mutants].

Study of the polypeptide content of erwiniophage ZF40c(5/5) and ZF40-421 virulent mutants has shown that their virions include no less than 10 structural proteins with molecular weights ranging from 16.9 to 96.5 kDa. Three polypeptides belong to a group of major proteins with molecular weights 39.2, 33.1 and 18.5 kDa. They correlate with the polypeptides of phage head, tail sheath and tail core correspondingly. It has been proven that the protein contents of these phages are identical, taking into account that the percent ratio of all polypeptides approaches 1.0. The polypeptide profile of isogenic variant of phage ZF40-421 obtained on EccRC5297 is characterized by another ratio of major proteins. These differences are reflected in the structure of procapsids, that explains low level of stability and viability of the variant. The work shows for the first time the possibility of using HPLC-chromatography for studying native phage particles and their structural components.

[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.

[Transduction as one of the methods of obtaining genetic information in Erwinia].

Transduction is one of the key processes of horizontal transfer of genes in bacteria. It is known that it is involved in distribution of the main factors of pathogenicity among numerous enterobacteria. It is shown that clear mutants and some variants of the temperate bacteriophage ZF40 Erwinia carotovora subsp. carotovora can perform general transduction of chromosome and plasmid genes of the bacterium E. carotovora. The indicators of chromosome transduction frequencies of the markers--arg+, met+, trp+, ura+ have a broad range of values: 7.10-10(-8) - 1.1-10(-1). The authors have succeeded in increasing the transduction efficiency due to infecting the recipient bacteria on the solid medium LB. Such approach is important for the phages similar to ZF40 in which adsorption is accompanied by re-adsorption of phage particles. The mechanism of transfer of bacterial genes by the type of general transduction is connected with cyclic permutation of phage DNA.

[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.

[Destabilization of defective lysogeny as the index of population dissociation of Erwinia carotovora].

The method of quantitative determination of bacteriocinogenicity in Erwinia carotovora dissociants has been suggested. It is based on the application of indicator bacterial mutants that are resistant to nalidixic acid. It has been revealed that population dissociation destabilizes a defective lysogeny of pectolytic Erwinia. In particular, a decrease of cell indicator survivability due to an increase of active bacteriocins yield has been found under lysogenic induction of defective prophages. The reverse dependence between the indicator cell survivability caused by dissociants bacteriocins induction and the reaction of hypersensitivity on leaves of the resistant plant Nicotiana tabacum, has been revealed. Similar dependence has been determined between dissociation and activity of pectate lyase. It has been hypothesized, that viable erwiniophages, being involved in the process of lysogenicity and induction, could play the role of 'switches' of bacterial phenotype raising adaptive phytopathogene reactions. The paper is presented in Russian. K e y w o r d s: Erwinia carotovora, defective lysogeny, population dissociation, reaction of hypersensitivity, activity of pectate lyase.

[Physico-chemical properties of temperate bacteriophage ZF40 of Erwinia carotovora].

A method of efficient purification of the extremely instable virions of the temperate bacteriophage ZF40 of Erwinia carotovora was proposed in the work. The stage-by-stage centrifugation in mentrizamide and caesium chloride gradients permitted to obtain highly purified phage preparations which were used for studying the protein composition of the studied erwiniophage. It was established that the buoyant density of the phage ZF40 was 1.23 g/cm3, 1.49 g/cm3 and 1.27 g/cm3 in the gradients of metrizamide, caesium chloride and caesium sulphate, respectively. By the polypeptide composition of the virion the phage ZF40 has been included in the group of P2-like phages.

[Comparative study of properties of temperate erwiniophages 49 and 59]. / Sravnitel'noe izuchenie svoistv umerennykh érviniofagov 49 i 59.

Molecular-biological properties of two relative temperate erwiniophages 49 and 59 have been comparatively studied. The both phages are highly specific with respect to sensitive bacteria and lyse only inconsiderable quantity of amylovora-like strains of Erwinia horticola. It has been established that erwiniophages are distinguished by the basic parameters of a single reproduction cycle in the cells of common host E. horticola 450. Considerable differences between phages have been also found in the areas of genomes responsible for the establishment and maintenance of lysogenic state in the cells of the bacterium-host. Study of structure polypeptides has confirmed the identity of capsids and tails of phages 49 and 59. It has been shown that phage 49 has another, as compared to phage 59, basal plate, which availability destabilises the phage tail and leads to virion destruction under various physical effects. Virion DNA of phages 49 and 59 are of the same size--47.9 kbp, but differ as to GC-content. Using the restriction analysis it has been shown that genome of phage 49, as well as the genome of phage 59, is permuted, but its permutation is of discrete character. The fact of recombination interaction between erwiniophages 49 and 59 has been established. It is supposed that phage 49 is the recombination (hybrid) derivative of phage 59 and unknown phage, or prophage, genetic module. The given recombination, probably, took place under the persistence of different phages in the general polylysogenic system of E. horticola.

[Factors that affect transduction in microorganisms]. / Faktory, vliiaiushchie na transduktsiiu u mikroorganizmov.

Data from literature concerning general and specialized transduction in microorganisms are given in the paper. The process of exogenic DNA penetration to the cells of bacteria and participation of protein products of separate phage genes in this process are described. The so-called E-proteins in a set with DNA penetrate through a cell membrane. In phage P22 they are protein products of phage genes 7, 16, 20. In P22 mutants with an altered transducing frequencies (HFT and LFT) the due functions are also coded by the phage genes. It is shown that the process of DNA packing in phages P22, phi 80, lambda and others is genetically determined. The gene transfer frequency depends on UV radiation and the very nature of transducing phages itself. In virulent phages the UV radiation up to inactivation level 95-99% evokes a decrease of their "killer" ability, which is accompanied by an increase of survivability of the formed transductants and, as a result, by enhancement of the transduction transfer frequency. An important role of the transduction analysis for fine mapping of a genome of microorganisms and its significance for practice are shown. A mathematical analysis of the data on cotransduction of linkage markers is presented as such that may be used when determining the value of transduced fragment of a chromosome.

[Plasmid R68.45 and S-a transduction by the temperate bacteriophage 59 of Erwinia carotovora 268]. / Transduktsiia plazmid R68.45 i S-a umerennym bakteriofagom 59 Erwinia carotovora 268.

Temperature bacteriophage 59 of Erwinia carotovera 268 had transduced extrachromosomal DNA: plasmids of R68.45 and S-a. Before plasmid transduction experiments the suitable donor strains of indicator culture Erwinia horticola 450 harbouring R68.45 and S-a were created. The frequency of plasmid R68.45 transfer from Pseudomonas putida to E. horticola 450-8 by conjugation was equal to 5 x 10(-8) per a donor cell and in the case of S-a--from E. coli C600 for the same recipient cells--was 2 x 10(-6). Bacteriophage 59 has transduced only separate markers of plasmid R68.45, since plasmid S-a is probably transduced by the phage as an intact unit.

[Characteristics of transduction in Erwinia by phage 59]. / Osobennosti transduktsii érvinii fagom 59.

A temperate bacteriophage 59 from polylysogenic strain Erwinia carotovora 268 transduces the following genetic markers: arg+, ilv+, leu+, met+, thr+, thy+, trp+, ura+. The transduction frequencies varied from 1 x 10(-8)- to 1 x 10(-6) and dependent on the multiplicity of infection, UV-irradiation of transducing bacteriophage, the nature of phage lysates. The characteristics of single transductants have been studied. Analysis of the obtained results suggests bacteriophage 59 to perform the generalized transduction.