Agrobacterium-mediated transformation of Nicotiana glauca and Nicotiana sylvestris.

Agrobacterium-mediated transformation is the most popular approach for obtaining transgenic plants nowadays. There are plenty of protocols developed for different plant species. These protocols usually include the medium composition, the technology for preparing plant explants and cultivation conditions, as well as the choice of agrobacteria strains. Nicotiana tabacum, or cultivated tobacco, was one of the f irst successfully transformed plant species. Nicotiana tabacum is a model object in plant genetics, particularly due to its ability for transformation and regeneration. N. tabacum is a naturally transgenic plant since its genome contains a cellular T-DNA acquired from Agrobacteria. The signif icance of cT-DNA for plants has not yet been established. Some assume that cT-DNA can increase the ability of plants to regenerate due to some of the genes they contain. For example, rolC has been shown to affect the hormonal balance of plants, but the molecular mechanisms underlying this have yet to be found. RolC is also somehow involved in the secondary metabolism of plants. Like N. tabacum, Nicotiana glauca produces a wide range of secondary metabolites and contains an intact rolC gene in its genome. At the same time, unlike N. tabacum, N. glauca is a diploid species, which makes it more suitable for genetic engineering approaches. Nicotiana sylvestris is one of the ancestral species of N. tabacum and does not contain cT-DNA. The aim of this work was to develop a protocol for transformation and regeneration of N. glauca and N. sylvestris. We managed to find an optimum ratio of auxins and cytokinins that promotes both active callus formation and organogenesis in N. glauca and N. sylvestris leaf explants. The developed technique will be useful both for fundamental research that includes the N. glauca and N. sylvestris species, and for practical application in the pharmaceutical industry and biosynthesis.

[Opine biosynthesis and catabolism genes of Agrobacterium tumefaciens and Agrobacterium rhizogenes].

Agrobacterium is a genus of soil bacteria with the ability to transform plant cells by a T-DNA-sequence located on the pTi/pRi- plasmid containing a set of genes expressed in plant cells. Expression of these genes leads to a proliferation of transformed cells, with the subsequent formation of tumors or growths of roots and the synthesis of opines--products of the condensation of amino acids with ketoacids or sugars used by Agrobacteria as a source of carbon and nitrogen. In this review, we systematized the information about most common opines in plant--Agrobacterium systems and their biosynthesis and catabolism genes, as well as the role of opines in the interaction of pathogenic Agrobacterium with plants and with other Agrobacterium strains, including the genetic consequences of such interactions.

[The chronic form of tick-born encephalitis with a clinical manifestation of disseminated encephalomyelitis (case description)].

In most cases, the chronic form of tick-born encephalitis (CTBE) develops after the acute phase of the disease and is characterized by polymorphic clinical manifestations. It is not often to see patients with disseminated encephalomyelitis in case of CTBE. We describe a patient with CTBE developed 12 years after the acute phase of the disease, which had a remitting course and clinically revealed multifocal lesions. MRI lesions did not differ from those caused by multiple sclerosis and the differential diagnosis of the latter was performed. The analysis of epidemiological data as well as the standard neurological examination in combination with the laboratory diagnostic methods allowed us to confirm the diagnosis of CTBE.

[Tumor formation in plants]. / Opukholeobrazovanie u rastenii.

The data on genetic tumors in plant species and interspecific hybrids, as well as the problems of Agrobacterium-induced tumors are reviewed. The role of the horizontal gene transfer in the induction of genetic tumors is discussed.

[The role of phytohormones in tumor formation in radish]. / Izuchenie roli fitogormonov v protsesse opukholeobrazovaniia u redisa.

Tumor formation was studied in inbred radish lines that produce tumors on plant roots during flowering. In all radish lines under consideration, the sequences homologous to oncogenes tmr/tml of Agrobacterium tumefaciens were revealed by Southern hybridization. No sequences homologous to the tms locus of A. tumefaciens and the oncogenes of A. rhizogenes were determined. It was found that auxin sensitivity and the tumor-producing capacity were coinherited. We suggest that tumor phenotype arise as a result of a combination between agrobacterial "cytokinin" oncogenes and certain alleles of "auxin" radish genes.

[Effect of azacytidine on expression of traits concomitant with tumor formation in the radish (Raphanus sativus) in vitro]. / Vliianie azatsitidina na proiavlenie priznakov, soputstvuiushchikh opukholeobrazovaniiu, u redisa (Raphanus sativus) in vitro.

The effect of azacytidine, a demethylating agent, on the expression of traits concomitant with tumor formation was studied in inbred radish (Rhaphanus sativus) lines carrying genomic sequences homologous to the tmr/tml genes of Agrobacteriium tumefaciens. AzaC was found to have no effect on the traits studied, which provided evidence that the capacity for tumor formation in radish lines does not depend on the level of methylation of these sequences.

[Mechanism of formation of active T-rosette forming cells in multiple sclerosis patients]. / O mekhanizme formirovaniia aktivnykh T-rozetkoobrazuiushchikh kletok u bol'nykh rasseiannym sklerozom.

On the basis of examining active rosette-forming T-lymphocytes contained in the peripheral blood of patients with disseminated sclerosis a relationship between the changes in the percentage of lymphocytes with different number of erythrocyte adhesions and the morbid process phase was discovered. The regularity of this phenomenon has given the authors grounds to assume that the diminution of the number of active rosette-forming T-lymphocytes (with 7 and more erythrocyte adhesions) in patients with disseminated sclerosis is due to redistribution of the various lymphocyte populations in the process of the immune response. This redistribution may be due to the lymphocyte fixation in the target and the immunocompetent organs.

Investigation on the role of viral antibodies in the pathogenesis of multiple sclerosis.

An attempt was made to elucidate the role of antibodies to measles, rubella and mumps viruses in the pathogenesis of multiple sclerosis by correlating their levels in the blood of patients with clinical manifestations of the disease. Antibody titres to measles and rubella viruses were higher during exacerbations of the process and decreased during remissions. No correlation was found between the level of viral antibodies and the duration of the disease, features of its course (rapidly or slowly progressing), or the phase of the disease. The rise of viral antibody titres in multiple sclerosis appears to be a secondary process not associated with the disease aetiologically and playing no role in its pathogenesis.

[Polymorphonuclear rosettes in the peripheral blood of multiple sclerosis patients]. / Polimorfnoiadernye rozetki v perifericheskoi krovi bol'nykh rasseiannym sklerozom.

The study is related to the distribution of rossette-forming cells--lymphocytic and polymorphonuclear leukocytic--lymphocytes and polymorphonuclear leukocytes (neutrophils) in the peripheral blood of patients with disseminated sclerosis. An increase of the polymorphonuclear leukocytes and polymorphonuclear leukocytic content was found in the exacerbation period. Similar data were obtained in the process of reproduction of chronic experimental allergic encephalitis in maccaca rhesus. Moreover, in a rapid development of the disease polymorphonuclear leukocytic cells in the patients did not differ from the control group. The established distribution of lymphocytes and polymorphonuclear leukocytes and polymorphonuclear leukocytic cells correlated with the accelerated maturation of leukocytes in the neutrophil range in the bone marrow. The possible role of polymorphonuclear leukocytes in the pathogenesis of disseminated sclerosis is discussed.