[Properties of pectolitic phytopathogenic bacteria isolates obtained in Ukraine].

Bacteria obtained from potato tubers having symptoms of soft rot and grown in different regions of Ukraine are identified as Pectobacterium carotovorum subsp. carotovorum. These bacteria strains are able to produce bacteriocines. Their killer activity in respect of P. carotovorum and Esherichia coli has been studied. The sensitivity to bactericines has been shown. Purified fractions of bacteriocines having high molecular weight (MCTV) have been obtained. The difference in composition of proteins from phage tails as compared to the ones in P. carotovorum J2 has been studied by the method of electrophoresis. It was found that the composition of MCTV major proteins of studied isolates mostly corresponds to P. carotovorum J2. The set of enzyme minor fractions has some different compositions as compared to P. carotovorum J2. It has been hypothesized that this difference is responsible for killer specificity.

[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.

[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.

[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.

[Nature of the cryptic plasmid pCA25 of Erwinia carotovora subsp. carotovora 48A].

High specificity of Tn9 transposition into the cryptic plasmid pCA25 of Erwinia carotovora subsp. carotovora 48A was established on the basis of the comparative restriction analysis of DNA by endonucleases EcoRV and PstI. Under the extremal conditions of growth (1% SDS) the plasmid pCA25:: Tn9 loses about 50 % of transpozone sequence, however the cells are not healed of extrachromosomal DNA. The inheritance stability, side by side with site-specific transposition and deleting of Tn9, confirms a supposition on the prophage origin of extrachromosomal element pCA25 of E. carotovora subsp. carotovora 48A.

[Method for transformation of Erwinia carotovora subsp. carotovora cells by plasmid pECL18].

A method for transformation of Erwinia carotovora subsp. carotovora cells has been developed. Transformants of E. carotovora RC 5297 (pECL 18) have been obtained. The transformation frequency was 5.4 x10(2) per 1 microg of DNA. This value depends considerably on the culture growth stage and the amount of calcium chloride used for obtaining the competent cells. The spontaneous loss of the plasmid is below 0.1% per one generation of cells. Both the plasmid and the host RM-systems behave autonomously, i.e., they restrict the development of phages independent of each other. Results obtained are a precondition for creating vectors based on E. carolovora being nonpathogenic for people, endogenic and exogenic plasmids.

[The multiple character of mutation of resistance to mitomycin C in Erwinia carotovora subsp. carotovora].

It has been shown that mutants of Erwinia carotovora subsp. carotovora (ECA) resistant to mitomycin C could be characterized by the change of colonies morphology, sensitivity to bacteriocins, and by the change of pathogeneity. It is supposed that mutations responsible for the stability to mitomycin C touch the synthesis of cell membranes components. In some cases MCr-mutations caused cardinal changes--the loss of prototrophy and synthesis of carotinoid pigment. The mutants obtained in this work can be used to study the pathogenic process in Erwinia carotovora. Some of MCr- mutants are the handy indicators of carotovoricins.

[Method for studying horizontal transfer of plasmids in Erwinia carotovora]. / Metod issledovaniia gorizontal'nogo perenosa plazmid u Erwinia carotovora.

A simple method to determine frequency characteristics of the horizontal transfer of antibiotic resistance by transconjugative plasmids of various incompatibility groups into Erwinia carotovora strains has been developed. The proposed method for selection of E. carotovora transconjugates provides for the use of selective medium with pectin and corresponding antibiotic, which permits carrying out reliable counterselection of the donor (Escherichia, Salmonella). The proposed method helped to study horizontal transfer of plasmids RP4 (Inc P), R 391 (Inc J) and pKM101 (Inc N) to some E. carotovora strains and to demonstrate their inheritance as extrachromosomal DNA in Erwinia cells.

[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.

[Vitamin para-aminobenzoic acid inhibits development of SOS function in tif-1 mutants of Escherichia coli at nonpermissive temperatures]. / Vitamin para-aminobenzoinaia kislota prepiatstvuet razvitiiu "SOS"-funktsii v tif-1-mutantakh Escherichia coli pri nepermessivnoi temperature.

The development of "SOS" inducible functions in lysogenic and non-lysogenic strains of Escherichia coli tif-1 sfiA11 (lambda) at nonpermissive temperature of 42 degrees C was strongly suppressed by para-aminobenzoic acid (PABA). The rate of prophage lambda induction decreased 400 times, as compared to the control level; the efficiency of W-reactivation of UV-irradiated phage lambda decreased 37.5 to 16%. PABA also inhibited to some extent (1.5 times) the process of inducible recombination on the RecF pathway. The processes of spontaneous lambda induction and W-reactivation, as well as spontaneous recombination on RecBC and RecF pathways, were not influenced by PABA. The above data are in accordance with previous studies of PABA action when the manifestation of "SOS" functions was induced by chemical mutagens. The action of PABA has been tentatively interpreted on the basis of negative control of "SOS" repair pathway.