[Characterization of Escherichia coli donor-specific RNA-containing bacteriophages].

The biological properties of 9 clones of Ri bacteriophages isolated from sewage water in 1981 were studied. On the basis of the activity of Ri phages with respect to E. coli donor-specific strains K12, the type of negative colonies, the ultrastructure of the virion and its sizes, adsorption on the pili of host cells, the latent period, the amount of harvest obtained from one infected cell, the clones under study were classified with small spherical RNA-bacteriophages. The neutralization of Ri phages with antiphage sera to standard phages f2 and fr made it possible to classify them with the first serological group and to divide them into 3 subgroups.

[Biological properties of bacteriophages, active to Yersinia enterocolitica]. / Biologicheskie svoistva bakteriofagov, aktivnykh v otnoshenii Yersinia enterocolitica.

The biological properties of 16 clones of Y. enterolitica bacteriophages were tested to select the most active for subsequent use. For the first time Y. enterocolitica virulent phages belonging to the family of Podoviridae were described and 7 serological groups of phages with no cross reactions were registered. The technology for the production of new therapeutic and prophylactic Y. enterocolitica polyvalent bacteriophage under laboratory conditions was developed. The effective multiplicity of contamination ensuring the maximum release of phages from bacterial cells, the optimum incubation temperature and the time of exposure were established. The experimental batches of therapeutic and prophylactic Y. enterocolitica polyvalent bacteriophage thus obtained met the requirements for antibacterial preparations.

[Antibiotic resistance plasmids in various strains of Staphylococcus aureus]. / Izuchenie plazmid antibiotikorezistentnosti iz razlichnykh shtammov Staphylococcus aureus.

Plasmids with the molecular weights of 1.6 to 21.0 MD were detected in Staphylococcus aureus. The plasmids determined resistance to benzylpenicillin, ampicillin, streptomycin, erythromycin, tetracycline, chloramphenicol, arsenate and arsenite. Strain p16 of Staphylococcus aureus contained plasmid pL16 with the molecular weight of 18.0 MD determining resistance to erythromycin, streptomycin, benzylpenicillin and ampicillin. The plasmid has two replication sites and is likely a natural recombinant of two plasmids.

[Conjugative R plasmids isolated from hospital strains of Pseudomonas aeruginosa]. / Izuchenie kon"iugativnykh R-plazmid, vydelennykh iz gospital'nykh shtammov sinegnoinoi palochki.

It was shown that Pseudomonas aeruginosa hospital strains isolated from patients and environment in the Republican Centre of Burns in Tbilisi contained conjugative R plasmids. The plasmids were marked pM15 and pM19, respectively. The plasmid pM15 determined resistance to carbenicillin, kanamycin and tetracycline and plasmid pM19 determined resistance to carbenicillin, kanamycin, tetracycline, chloramphenicol, gentamicin and streptomycin. Plasmid pM15 had a molecular weight of 45.8 MD and seven sites for EcoRI, six sites for HindIII and five sites for Hpa-I-restrictase. This plasmid, as others, belongs to the Inc-P1 incompatibility group.

[Antibiotic sensitivity and pathogenetic factors of hospital strains of Pseudomonas aeruginosa isolated from patients treated in a resuscitation unit]. / Antibiotikochuvstvitel'nost' i faktory patogennosti gospital'nykh shtammov sinegnoinoi palochki, vydelennykh u bol'nykh reanimatsionnogo otdeleniia.

Strains of Pseudomonas aeruginosa were isolated from patients treated in the Centre of Thermal Affections in 1985-1989. It was shown that 72.9, 59.3, 33.8 and 54.2 per cent of the isolates were sensitive to cefotaxime, tobramycin, gentamicin and polymyxin, respectively. The study of pathogenicity factors of the isolates revealed that 83 per cent of the strains produced thermolabile enterotoxin, 79.6 per cent of the strains had adhesive activity and 71.1 per cent of the strains produced hemolysin. The study detected combinations of various pathogenicity factors. 42.3 per cent of the isolates had both adhesive and enterotoxigenic properties. Adhesiveness and hemolytic activity were shown by 13.5 per cent of the strains. 16.9 per cent of the strains produced both enterotoxin and hemolysin. Adhesive activity, enterotoxigenicity and hemolysin production were observed in 6.7 per cent of the strains. It was noted that the strains of P. aeruginosa resistant to polymyxin mainly produced enterotoxin (18.6 per cent) and those resistant to cefotaxime had adhesive activity (34.0 per cent).

[The pathogenicity factors of bacteria in the genus Acinetobacter]. / Faktory patogennosti u bakterii roda Acinetobacter.

Eighty Acinetobacter strains, isolated in Togliatti from patients with purulent inflammatory diseases, were studied to determine their pathogenicity factors. Out of these 80 strains, 32.5% were found to have enterotoxigenic activity and 46.2%, adhesive activity. They were related to adhesins of the human type and to adhesins of the sheep, rabbit, swine and guinea pig types. But the most important phenomenon established in this study was the combination of different pathogenicity factors detected in Acinetobacter bacteria. Analysis of the combination of pathogenicity factors revealed that 7.5% of Acinetobacter strains had adhesive and enterotoxigenic activity, 15.3% of these strains combined adhesive and hemolytic activity and 1.2% of them were found to be enterotoxigenic and hemolytic. Only 5.0% of Acinetobacter strains were found to carry all there pathogenicity factors simultaneously.

[New systems of host specificity of DNA Pae 610 and Pae 603]. / Novye sistemy khoziaiskoi spetsifichnosti DNA Pae 610 i Pae 603.

In order to find new systems of host specificity (SHS), wide screening among different strains of Ps. aeruginosa was carried out. By means of cross-titration of phages BT and FP-series two new systems of modification-restriction were identified: Pae 610 and Pae 603. They differ from the known system of host specificity Pae R7.

Host-controlled modification and restriction as a criterion of evaluating the therapeutical potential of Pseudomonas phage.

The recently isolated phages phi ST3 and phi ST1 were compared as to their lysis behaviour in about 100 different P. aeruginosa strains. The growth of phi ST3 varies greatly in different host strains. We demonstrated one case of "non-classical", host-dependent modification and restriction. Here the capability to adsorb, and consequently to reproduce in a given host strain differs, depending on which modification the phage acquired in its former host. The DNA-containing phage phi ST1 displays stable lysis properties in the majority of the host strains. This makes phi ST1 a candidate for therapeutic phage preparations. One of the reasons for stable lysis properties is the apparent selection against recognition sites of restriction enzymes in its genome.

The virulent bacteriophage IRA of Salmonella typhimurium: cloning of phage genes which are potentially lethal for the host cell.

Morphological and biological properties of Salmonella typhimurium phage IRA were studied. The phage is a member of the Styloviridae family and exhibits a very wide spectrum of lytic activity. Molecular cloning of phage genes whose expression is lethal for the host cell has been performed and consequences of gene expression have been investigated. Expression of recombinant plasmid pKI71 causes structural changes of the cell wall and also degradation of host DNA while plasmid DNA remains intact. Expression of pKI72 blocks normal cell division. The possibility of applying such recombinant clones in marking pathways of microbial contamination in water areas is proposed.

[Experimental study of the interaction of phages and bacteria in the environment]. / Eksperimental'noe izuchenie vzaimodeistviia fagov i bakterii vo vneshnei srede.

For the first time the possibility of the interaction of phages and bacterial cells in the environment, consisting in the adsorption and subsequent replication of viral particles, has been shown. The data obtained in this investigation provide grounds for using phages in the environment. Experiments with Escherichia coli M-17 and phage FM17, carried out on experimental models, have demonstrated that the use of phages in the environment completely prevents the realization of the transfer of enteral infections through everyday contacts and the contamination of children and adults under hospital conditions.

[Changes in the functional activity of the liver cells in rabbits during a bacterial infection]. / Izmenenie funktsional'noi aktivnosti kletok pecheni krolikov v protsesse bakterial'noi infektsii.

In the process of the development of bacterial infections, the activity of marker enzymes in the membrane structure of liver cells has been studied in rabbits by biochemical and electron-histochemical methods. The results of these studies have shown that, simultaneously with the progressing course of cell pathology and inhibition of the function of mitochondria, microsomes and peroxisomes, the lysosomes activate for the realization of the protective function formed in the course of evolution. At the same time the excessive labilization of lysosomal membranes facilitates the development of cell pathology, which is confirmed by the accumulation of residual bodies in the cytoplasm.

[Morphological changes in the liver cells of rabbits with a bacterial infection]. / Izuchenie morfologicheskikh izmenenii v kletkakh pecheni krolikov pri bakterial'noi infektsii.

In the process of bacterial infection in rabbits, their livers have been studied by means of light and electron microscopy, as well as by morphometric analysis. The results evidence pathomorphologic and ultrastructural changes occurring in liver cells. These changes, probably, cause different metabolic disturbances and thus facilitate the development of destructive processes in vital organs.

[Modelling of the epidemic process of suppurative septic infections using a Pseudomonas aeruginosa bacteriophage]. / Modelirovanie épidemicheskogo protsessa gnoino-septicheskikh infektsii s pomoshch'iu bakteriofaga k Pseudomonas aeruginosa.

The method for modeling the epidemic process of pyoseptic infections with the use of P. aeruginosa bacteriophage is proposed. The application of this method in urological and traumatological wards has made it possible to confirm the role of patients as the sources of infection and the part played by instruments and the hands of the medical personnel in its transfer.

[Purification and properties of staphylococcal hyaluronidase]. / Ochistka i svoistva stafilokokkovoi gialuronidazy.

Microbial hyaluronidase (EC 4.2.2.1) was isolated from the culture fluid of Staphylococcus aureus 0-15 with purification by precipitation with 1 volume of ethyl alcohol, chromatography on DEAE cellulose and ultrafiltration through DA type membranes with the pore size of 0.65 micron ("Millipore") and PM-10 membranes ("Amicon"). The specific activity of the enzyme averaged to 2700 turbidimetric units or 32130 IU. 6585-fold purification of the enzyme was performed. The optimum action on hyaluronic acid was observed at pH 5.0-6.5. Hyaluronidase was inhibited by Fe3+, Fe2+ and Cu2+, activated by Ca2+ and stabilized by 0.15 M NaCl. It was detected that the enzyme had two molecular forms with the isoelectric points of 5.4 and 6.5 and the molecular weights of 55 000 and 24 0000 D respectively. The glycoprotein nature of the enzyme was shown. The immobilized form of hyaluronidase on activated polyglucin, a soluble biocompatible polymer was prepared. The form is characterized by higher thermostability.

[Role of lysosomes during the development of a fibroblast staphylococcal infection]. / Rol' lizosom v protsesse razvitiia stafilokokkovoi infektsii fibroblastov.

The study of staphylococcal infection in chick embryo fibroblasts, carried out by electron-histochemical and morphometric methods, has revealed the presence of correlation between the degree of fibroblast destruction and the permeability of lysosomal membranes. The development of bacterial infection, depending on the presence of homologous bacteriophages in the medium, has also been studied.

[Modification of the modification-restriction system in staphylococci]. / Identifikatsiia sistem modifikatsii-restriktsii u stafilokokkov.

A new system of host specificity of DNA, called Sau67 according to the available nomenclature, was identified in Staphylococcus aureus 6782 strain by means of cross titration with staphylophage 729 considering that the phage exhibited the highly effective absorption properties. A total preparation of Sau67 methylases was isolated using ammonium sulfate fractionation. The enzyme preparation contained methylases of cytosine and adenine, where the activity of adenine methylases constituted only for 5% of the total methylase activity. As shown by kinetics of methylation low content of unspecific cellular nucleases was found in the St. aureus 6782 strain; these reasons are important for isolation of restricting endonucleases containing in the strain. 100 micrograms of protein of the total enzymatic fraction enabled to methylate the acceptory DNA at the maximal rate within 1.5 hr of incubation in phosphate buffer, pH 7.9. The fraction of cytosine methylases free of adenine methylating activity was obtained after chromatography on Sepharose blue with NaCl concentration stepwise gradient.