[Role of phage LØ7 lysogeny in genetic variability of Escherichia coli].

Aim: Determine the possibility of Iysogenization of Escherichia coli single strain DNA (ssDNA) by 1ø7 bacteriophage from the Microviridae family and determine the role of phage lø7 lysogeny in genetic variability of these bacteria.

Materials And Methods: A method of E. coli K12 lysogenization by phage lø7 was developed.

Photoelectrochemical properties of a dinitrogen-fixing iron titanate thin film.

The band edge positions of a nitrogen-fixing nanostructured semiconductor thin film are determined both in the dark through spectroelectrochemistry and under irradiation by photovoltage measurements. Both methods afford the same result indicating that the film in addition to the dinitrogen-fixing phase Fe2Ti2O7 also contains titanium dioxide. Thus, both methods enable the analysis of a mixture of semiconducting thin films.

[SOS-induction in the presence of the plasmid pKM101 in the bacterial cells Escherichia coli K12].

Induction of transcription by the plasmid pKM101 (mutability mediating derivate of the plasmid R46) of the sfiA gene controlling cell division and of the fruA gene encoding the fructose specific enzyme II of the phosphoenolpyruvate-phosphotransferase system in intact cultures of Escherichia coli was studied. The genes under study were fused to the bacteriophage Mu dl (Ap lac). Activation of the sfiA gene, a typical member of the SOS-regulon, was demonstrated to depend on the key genes of the SOS-system-recA and lexA.

[Effects of plasmid pKM101 on the expression of Escherichia coli and Salmonella typhimurium genes under ultraviolet irradiation].

The study focused on plasmid pKM101, which is a necessary component of the short-term test of Eim's system (Salmonella-microsome test), to detect the potential carcinogens through their mutagen activity. We found a previously unknown feature of the plasmid to enhance the expression of certain plasmid and chromosome genes. The purpose of the present study was to examine and specify the role of operon mucAB responsible for the mutation properties of the plasmid in activating the expression of bacterial genes.

Nitrogen photofixation on nanostructured iron titanate films.

A nanostructured iron titanate thin film has been prepared by a sol-gel method from iron(III) chloride and titanium tetraisopropylate. Energy-dispersive X-ray analysis and Mössbauer spectroscopy suggest the presence of a Fe(2)Ti(2)O(7) phase, which was previously obtained as an intermediary phase upon heating ilmenite. In the presence of ethanol or humic acids and traces of oxygen, the novel film photocatalyzes the fixation of dinitrogen to ammonia (17 microM) and nitrate (45 microM).

Nitrogen Photofixation at Nanostructured Iron Titanate Films.

Mild reducing agents such as ethanol, sodium formate, and humic acids effect the photofixation of nitrogen to ammonia and nitrate at thin films of nanostructured iron titanates. The reaction occurs in the presence of air and light, but is inhibited by the presence of carbon monoxide.

[Effect of plasmid pKM101 on the expression of bacterial genes not related to DNa metabolism].

An experimental system ensuring fusion of bacterial genes to the lac operon of the Mu dl(Aplac) phage was used. Fusion operons in which the lac operon was under the control of promoters of the elt gene, responsible for synthesis of the LT toxin, of the tetracyclin-resistance tet gene, and sfiA gene encoding filament production, was studied. Using this experimental system, plasmid pKM101 was shown to be capable of activating the expression of the above Escherichia coli and Salmonella typhimurium genes, which is manifested as the activation of beta-galactosidase synthesis.

[Methods of the use of ketorolac tromethamine in patients during the early postoperative period].

Analgesia with nonsteroid antiinflammatory drugs (NSAID) becomes a pressing problem today. One such drug is ketorolak tromethamine (KT), characterized by expressed analgesic activity comparable with that of opioid analgesics morphine or promedol. Our purpose was to assess KT efficacy in analgesia performed by different methods, including analgesia controlled by the patient (ACP) after surgery.

[Relationship between the UV-induction of exact exclusion of transposons and the function of umuDC, lexA, recA genes and plasmid pkM101].

A pair of isogenic strains-E. coli K-12 and E. coli B/r differing by the status of umuDC genes and presence of pKM101 plasmid-were constructed and the relationship between UV induction of transposons Tn5 and Tn 10 and the gene umuDC function shown.

[A comparative analysis of UMUDC-dependent induction of tandem duplications, point and insertional reversions in Salmonella].

Comparative analysis of UV induction of tandem chromosome (Mtc+) duplications and reversions of point mutations (base pair substitutions) and of insertion mutations (precise excision of Tn10) was carried out. Salmonella (umuST) genes deficiency preventing dose-dependent UV induction of point mutation reversion were shown to have a less pronounced effect on the induction of tandem chromosome duplications. UV induction of tandem chromosome duplications is similar to UV induction of insertion mutation reversion: dose-dependent UV induction of both occurs in umuST Salmonella strains.

[UV-induction of the LT-toxin operon depending on genes lexA, recA, and umuD].

UV induction of the elt operon (the LT-toxin operon in Escherichia coli) was demonstrated in experiments using fusion of elt::lac operons with the help of Mud1(Ap lac) phage. UV induction of the elt operon is lexA-dependent; thus, the possibility of SOS regulation of this process may be assumed. However, UV induction of the elt operon turned out to be recA-independent, which makes it impossible to consider this induction as a typical SOS response.

[The status of the receptor-controlled calcium metabolism of the thrombocytes in patients in the early postoperative period].

Basic changes in receptor-controlled platelet calcium metabolism that occur in the early postoperative period under the effect of aggregation-inducing hormones--platelet activation factor (PAF), adenosine phosphate (ADP) and vasopressin--are reviewed. Patients after lung surgery and patients with ischemic heart disease after aortocoronary bypass surgery have been examined. Patients operated on for malignant lung tumours developed increased postoperative sensitivity to ADP, while in patients after aortocoronary bypass surgery the early postoperative period was characterized by decreased sensitivity to PAF and vasopressin.

[The toxic and immunomodulating properties of the somatic O-antigen polysaccharide of typhoid bacteria].

In experiments on random bred mice and mice of various strains it was shown that when administered parenterally typhoid bacteria O-somatic antigen polysaccharide possesses the immunomodulatory properties. It stimulates the non-specific resistance of the organism to bacterial infection, produces the polyclonal activation of beta-lymphocytes, possesses the adjuvant properties, activates cells of the mononuclear phagocytic system. At administration in therapeutic doses the drug is not toxic, possesses no carcinogenic, mutagenic and allergenic properties.

[UV-inducibility of the LT-toxin operon].

The plasmid elt-operon pVZ14 was constructed by fusing of the eltoperon of the plasmid pVZ357 with the lac-gene of the bacteriophage Mud1 (Amp, Lac). lacZ gene has been proven to be fused with an elt-promoter by the loss of toxin production coded by pVZ357 and acquiring of Lac+ phenotype by pVZ14 containing cells, as well as by HindIII fragments hybridization of pVZ357 and pVZ14 with the labelled elt-probe. The kinetics of beta-galactosidase synthesis in E.

[SOS-induction of the RP4 plasmid tet-determinant].

Induction of the tetracycline-resistance genes function by the inducer of the DNA-repair and mutability SOS-system, UV-light, has been tested. Activity of the tet-genes residing on the plasmid RP4 in Escherichia coli cells has been shown to be inducible by the low doses of tetracycline as well as by the mutagenic doses of UV-light. The induction was quantitatively registered by measuring the activity of beta-galactosidase of bacteriophage Mud1 (Ap, Lac) inserted into the tet-genes of the plasmid RP4.

[Isolation of the R'his plasmids of Vibrio cholerae].

V. cholerae strain VT5104 capable of donor activity in conjugation has been constructed by the genetic technique based on plasmid RP4::Mucts62 integration into V. cholerae chromosome due to plasmid homology with Mucts62 inserted into the chromosome.

[Induced mutagenesis in Salmonella typhimurium AG262 strain constructed for screening the mutagens].

The Salmonella typhimurium strain AG262 has been constructed for screening of SOS-mutagens, such as UV-light and 4NQO, the Ames plasmidless tester strains of S. typhimurium being mutation-proof under the action of this class of mutagens. The strain AG262 has also been successfully used for screening of induced base pair change mutations occurring independently of cellular SOS-system of mutagenesis (MNNG, EMS, nitrofuran derivatives), and of the mutations induced by frame-shift mutagens (benzo/a/pyrene 7,12-dimethylbenzo/a/antracene ICR-191, 9AA, DDDTDP).