Developmental and hormonal regulation of Arabidopsis thaliana ornithine-delta-aminotransferase.

Ornithine aminotransferase (OAT) catalyzes transfer of the delta-amino group from L-ornithine to oxo-glutarate. In plants, this reaction biochemically connects urea cycle, proline cycle, and polyamine biosynthesis pathway. OAT activity is shown to be associated with biotic and abiotic stress responses and nitrogen metabolism, but its physiological role is still unclear. In our study, we decided to investigate transcriptional regulation of the OAT gene in Arabidopsis thaliana under normal conditions and in response to various growth regulators. In the present work, the reporter gene construct containing the Escherichia coli ß-glucuronidase gene (gus) under control of the A. thaliana OAT gene promoter was introduced into the genome of A. thaliana ecotype Columbia plants using the floral dip method; GUS activity was assayed in different experimental conditions including hormone treatment, low and high nitrogen and salinity. The GUS activity was analyzed histochemically. Plants were incubated with staining solution containing X-Gluc. We show that under standard growth conditions, the promoter is active during germination and in developing floral organs. OAT promoter activity specifically activates in response to different forms of auxin (IAA, NAA, and 2,4D), cytokinin (6- BAP), ethylene precursor (ACC), high nitrogen and salinity. Analysis of the OAT expression by qRT-PCR confirmed the pattern observed using the GUS reporter system. The OAT gene showed a significantly elevated expression in fourday- old seedlings and in plant roots in response to auxins and cytokinins. The analysis of the OAT promoter structure reveals cis-acting regulatory DNA elements associated with auxin regulation and abiotic stresses. The results of the study indicate that the OAT gene is involved in developmental processes and is regulated by auxin and cytokinins.

[Analysis of transcriptional activity of the ornithine-delta-aminotransferase gene promoter in Arabidopsis thaliana].

Cloning of the Arabidopsis thaliana genomic DNA fragment presumably corresponding to the promoter region of the ornithine-delta-aminotransferase (OAT) gene is reported. The reporter-gene construct, containing the Escherichia coli beta-glucouronidase gene under control of the OAT gene promoter was generated. The Nicotian tabacum SR1 transformants carrying this construct were obtained. It was demonstrated that in normal conditions, expression of the reporter gene was associated with the meristems and the zones of intensive shoot growth. Possible role of the OAT gene in nitrogen metabolism and shoot development is discussed.

[Tobacco transformants expressing the Medicago truncatula ornithine aminotransferase cDNA].

The Medicago truncatula ornithine aminotransferase cDNA was cloned under the potent constitutive 35S RNA promoter of the cauliflower mosaic virus and transferred into the genome of tobacco Nicotiana tabacum SR1 plants. Transformed tobacco plants grew better in salinity stress, but did not differ in proline content under normal or stress conditions from control plants. It was assumed that the role of ornithine aminotransferase in the molecular mechanisms of stress resistance is not associated with additional proline synthesis.

[The wound microflora of patients with gunshot injuries to the extremities during a mass hospitalization]. / Mikroflora ran bol'nykh v usloviiakh ikh massovogo postupleniia v statsionar s ognestrel'nymi povrezhdeniiami konechnostei.

The dynamic study of the microflora of bullet wounds in 32 patients was carried out. In cases of mass hospitalization coccal microflora (staphylococci and streptococci) was mainly isolated from wounds, at the period of treatment hospital infections with enterobacteria, Pseudomonas and Enterococcus occurred. Before cleaning the wound a decrease in the contamination rate for all microbial species was observed. As the disease progressed an increase in the amount of antibiotic-resistant bacterial strains was registered. The results of sanitary microbiological investigations made in the wards where the wounded patients were treated correspond to the structure of the causative agents of purulent processes in patients.