[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).