[Mapping of meiotic genes in rye (Secale cereale L.): localization of sy19 mutation, impairing homologous synapsis, by means of isozyme and microsatellite markers].

The sy19 mutation, which impairs the homology of meiotic chromosome synapsis in rye, were mapped using a specially created F2 population by means of isozyme Acph 1 locus and microsatellite (SSR) markers. The sy19gene was localized in the chromosome 7R in the pericentromeric region of long armbased on the linked inheritance with the Acph 1 locus. The locus was linked with five rye SSR markers, with the Xrems 1234 locus being located closest to the sy19 gene (6.4 cM). The genetic map of the analyzed chromosome 7R region includes ten markers and the sy19 locus. A possible function of the Sy1 and Sy19 genes based on the data on comparative genomics is discussed.

[Mapping of meiotic genes in rye (Secale cereale L.): localization of sy18 mutation with impaired homologous synapsis using microsatellite markers].

The recessive spontaneous sy18 mutation with nonhomologous synapsis was mapped in rye. The sy18 gene was located in the centromeric region of chromosome 2R in relation to three rye SSR (simple sequence repeats) loci, i.e., Xrems1130, Xrems1203, and Xscm43, and one wheat SSR locus Xgwm132. The desynaptic sy18 gene is located in the interval between Xrems1130 and Xrems1203 markers at a distance of 0.5 cM and 3.1 cM, respectively. The possible evolutionary relationships of the mapped gene with homologous loci of the related species are discussed.

[Genetic transformation of flax (Linum usitatissimum L.) with chimeric GFP-TUA6 gene for visualisation of microtubules].

The data of Agrobacterium-mediated transformation of some Linum usitatissimum cultivars zoned on the territories of Belarus and Ukraine with the plasmid carrying chimeric GFP-TUA6 gene and nptII gene as selectable marker conferring resistance to kanamycin are presented in this study. Transformation was affected by a number of factors including optical density (OD600), time of inoculation of explants with Agrobacterium and co-culture conditions. Transgenic nature of obtained lines was confirmed by PCR analysis. Expression of GFP-TUA6 gene was detected with confocal laser scanning microscopy. The obtained transgenic lines can be used for further functional studies the role of microtubules in the processes of building the flax fibres and resistance to wind.

[Polymorphism of SSR alleles in pear cultivars grown in Belarus].

Using SSR markers designed for Malus x domestica Borkh, genetic polymorphism of 43 pear accessions cultivated in Belarus was examined. A total of 217 alleles were identified with the mean number of 12.8 alleles per marker. The mean PIC value was 0.81; the mean number of informative alleles, 6.49. The heterozygosity level ranged from 0.30 to 0.84. Genetic diversity of SSR alleles in pear and apple genomes was compared. A method of identification of commercial pear cultivars using a set of six SSR markers was suggested.

Neurons and stromal stem cells as targets for polycation-mediated transfection.

Expression of transgenes in neurons and stromal/mesenchymal stem cells (MSC) can greatly enhance their therapeutic potential. In transfection experiments, we studied properties of linear and branched (dendrimers) polycations as transgene delivery vehicles. Linear polyethyleneimine transfected neurons, but was ineffective in MSC. Polyamidoamine dendrimers showed greater transfection efficiency and mean GFP fluorescence intensity compared to phosphorus dendrimers of the same (4th) generation. Expression of neurotrophic factor BDNF in MSC transfected with polyamidoamine dendrimers was also by more than 10 times higher.

[Neurogenic differentiation of mesenchymal stem cells: a transgenic approach].

Mesenchymal stem cells (MSC), alongside with "traditional" osteogenic, chondrogenic and adipogenic differentiation potentials, are considered by many researches as capable of giving rise to neurogenic lineage as well. We overview transgenic approaches to the study of neurogenic differentiation of MSC, including expression of neurotrophic factors, signalling molecules and other transgenes with neurogenic properties.

[Characteristics of steroid metabolism in transgenic Nicotiana tabacum plants bearing the CYP11A1 cDNA of cytochrome P450(SCC) from the bovine adrenal cortex].

In the mitochondria of animal steroidogenic tissues, cytochrome P450(SCC), encoded by the CYP11A1 gene, catalyzes the conversion of cholesterol into pregnenolone - the general precursor of all steroid hormones. In this work, we study the steroid metabolism in transgenic tobacco plants carrying the CYP11A1 cDNA cytochrome P450(SCC)from the bovine adrenal cortex. The transgenic plants under investigation markedly surpass the control wild-type plants by size and are characterized by a shortened period of vegetative growth (by rapid flowering); their leaves contain pregnenolone - the product of a reaction catalyzed by cytochrome P450(SCC). The level of progesterone in transgenic tobacco leaves is higher than in the control plants of the wild type. The seeds of the transgenic plants contain less (24R)-brassinosteroids than the wild-type tobacco plants. The results obtained indicate that the synthesis of an active P450(SCC) cytochrome in transgenic Nicotiana tabacum plants has a profound effect on steroid metabolism and is responsible for the specific phenotypic features of transgenic plants bearing CYP11A1 cDNA.

[Gene therapy based on human mesenchymal stem cells: strategies and methods].

Major technologies of transient and stable transgene expression in hMSC are reviewed. Properties and efficiencies of recombinant lentiviruses, adenoviruses, AAV and baculoviruses used for hMSC transduction are compared. The aims oftransgenesis include directed differentiation of hMSC, function improvement, correction of pathology factors and proliferatrion control, as well as many basic research challenges.

[Construction and characteristics of transgenic tobacco Nicotiana tabacum L. plants expressing CYP11A1 cDNA encoding cytochrome P450scc].

In steroidogenic animal tissues cytochrome P450scc catalizes the conversion of cholesterol into pregnenolone, a common metabolic precursor of all steroid hormones. To study the possibility of functioning of mammalian cytochrome P450scc in plants and the mechanism of its integration in the plant steroidogenic system, transgenic plants of tobacco Nicotiana tabacum L. were developed carrying cDNA of CYP11A1 encoding cytochrome P450scc of bovine adrenal cortex. Pregnenolone, a product of the reaction catalyzed by cytochrome P450scc, was discovered in the steroid-containing fraction of transgenic plants. Transgenic plants are characterized by a reduced period of vegetative development (early flowering and maturation of bolls) and increased productivity. The contents of soluble protein and carbohydrates in leaves and seeds of transgenic plants are essentially higher than the contents of these components in leaves and seeds of control plants.

Plasticity of human mesenchymal stem cell phenotype and expression profile under neurogenic conditions.

Human bone marrow MSC cultured in neurogenic medium containing EGF and FGFbeta demonstrated alteration of the phenotype and expression of neuronal precursor/early neuron markers nestin and NSE. Signals of expression of neuronal and oligodendroglial markers MAP-2, dm-20, and MBP were detected after prolongation of incubation in neurogenic medium to 2 weeks. Cells with neuronal morphology were immunopositive to early neuronal marker beta-III-tubulin. Replacement of neurogenic medium for alpha-MEM with 10% fetal calf serum induced reversion of the phenotype to that typical for human MSC. This indicates high plasticity of the phenotype and expression profile of neuronal markers in MSC cultured under neurogenic conditions or possibility of dedifferentiation of MSC reaching the stage of neuronal precursors/early neurons.

[Molecular genetic mapping of the sy1 and sy9 asynaptic genes in rye (Secale cereale L.) using microsatellite and isozyme markers].

Studies of phenotypical expression of synaptic mutations in combination with the localization of corresponding genes on a genetic map permit individual stages of the meiotic process to be differentiated. Two rye asynaptic genes, sy1 and sy9, were mapped with the use of microsatellite markers (SSR) in the pericentromeric regions of the long chromosome arms 7R and 2R, respectively. The sy9 gene cosegregated with two SSR markers Xscm43 and Xgwm132. The asynaptic gene sy1 was mapped within the interval between the isozyme locus Aat2 and two cosegregating loci Xrems1188 and Xrems1135 that are located at a distance of 0.4 cM proximally and 0.1 cM distally with respect to the gene lous. Possible evolutionary relationships of the mapped genes with homeological loci of the Triticeae species and more distant cereal species, such as maize and rice, are discussed.

[Chitinases in bioengeneering research].

Techniques of introduction of foreign genes into the plant genome have been intensely developed in order to directionally improve properties of crops. One of the key directions in plant bioengineering is searching for and analyzing promising genes, in particular, to construct genotypes with high resistance to pathogens and pests. In this review, the use for this purpose of transgenes coding for chitinase family enzymes is considered. Many of these transgenes have proved to be efficient factors for elevating plant resistance to pathogenic fungi.

[Pleiotropic effects of chitinase gene from Serratia plymuthica in transgenic potato].

We estimate the influence of transgenic bacterial chitinase from soilborne Serratia plymuthica onto agronomical important traits of potato, such as productivity and non-specific resistance. Transgene has been delivered into potato variety Delfin via Agrobacterial transformation with pGreen0229 and pBI121-based vectors. Growth inhibition of chitin-containing pathogenic fungi was shown. However, over 40% oftransgenic lines demonstrated decreased non-specific resistance to late blight (down to 62% compared to control genotype), as well as 40-60% productivity drop.

[The tolerance of tobacco genetically modified plants to aluminium].

Introduction of the vector constructions with rhamnolipid genes (rhlA and rhlB) into tobacco plants has resulted in development of genetically modified plants which were tolerant to high concentrations of aluminium. While under aluminium concentration of 200 mM in a soil (ionit resin) all control plants perished, transgenic tobacco plants continued to grow and were fertile.

[Experimental models for creation of transgenic plants resistant to stress factors].

Experimental models of the potato primary transgenic plants which express the hybrid gene cry3aM-licBM2 have been created. Modecular analysis and the biotests of the experimental models allow proposing a new system of cry genes expression in plants. The system is based on the expression of hybrid genes possessing the sequence of reporter lichenase gene and the use as a regulator element of a light-induced promoter providing preferential expression of the controled genes only in green plant tissues (leaves)--the target tissues for pests. The lichanase presence in hybrid proteins facilitates selection and analysis of the expression level of the hybris proteins in transgenic organisms. Basing on the lichenase properties in hybrid proteins it seems possible to use this reporter system for transgene monitoring in agrocoenosis as this system is rather simple and precise and does not need large material and time expenses.

[Identification of leaf rust resistance genes in wheat (Triticum aestivum L.) cultivars using molecular markers].

A collection of 68 cultivars of common wheat has been screened for leaf rust resistance genes with the use of molecular markers. Markers of genes Lr1, Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, and Lr26 have been used. It has been suggested that allele Xgwm295 be used as a marker for identifying the Lr34 gene. The genes originating from Triticum aestivum L., as well as the Lr26 gene contained in rye translocation 1RS, are the most frequent. Genes originating from wild wheats were rarer in the cultivars studied.

[Study of HRas1 minisatellite frequencies in children with thyroid papillary cancer]. / Izuchenie chastot minisatellita HRas1 sredi detei s papilliarnym rakom shchitovidnoi zhelezy.

The "rare" alleles of HRas1 gene minisatellite are well-known factor of predisposition to many kinds of cancer. We have studied HRas1 minisatellite frequencies among patients with papillary thyroid cancer which is related to consequences of Chernobyl accident. The HRas1 minisatellite was analysed in 32 patients who suffered from papillary carcinoma and underwent operation in 1996-2001 and in 75 Belorussian residents. Of 64 HRas1 alleles revealed in patients 14 were defined as "rare" (21.9%); in the control group we have detected 17 "rare" alleles (11.3%) of the examined 150 alleles. The higher frequency of "rare" HRas1 minisatellite alleles in patient group was statistically significant (p < 0.01). We can suppose that the "rare" alleles of HRas1 minisatellite are associated with increased risk of papillary thyroid cancer formation in children and adolescents after Chernobyl accident.

[Comparative molecular-genetic mapping of genomes of rye (Secale cereale L.) and other cereals]. / Sravnitel'noe molekuliarno-geneticheskoe kartirovanie genoma rzhi (Secale cereale L.) i drugikh zlakov.

The genetic map of rye consisting of 149 RFLP, 20 isozyme and 12 microsatellite markers was developed. Using the collection of cross-hybridizing probes, the presence of multiple translocations in rye genome with respect to wheat and barley genomes was shown. However, within large regions of genome a strict collinearity of marker order was observed that allow us to use the method of comparative mapping for an introduction of new genes. In the developed genetic map 18 morphological and breeding-valuable genes mapped in different rye populations were integrated. The comparative analysis of homeological loci in genomes of Triticeae species as well as in genomes of rice and maize was carried out. The genes controlling a number of morphological traits, plant height, photoperiodic response and winter/spring growth habit were shown to be conserve among cereals and to form clear homoeologous rows.

[Modulation of the cat gene expression in E. coli cells by simple (AC)20 repeats]. / Moduliatsiia ékspressii gena cat v kletkakh E. coli prostym povtorom (AC)20.

Probable relationship between modulation of gene expression by simple repeating sequences and competition capacity of the host was studied. (AC)20 repeat can both stimulate and inhibit the expression of chloramphenicol acetyl transferase gene expression in E. coli cells depending on this gene's position. Modulation of the gene expression by simple (AC)20 repeat and competitive capacity of bacteria containing this plasmid are closely related.

[ret/PtC1 and ret/PTC3r1 rearrangement in thyroid cancer cells, arising in residents of Belorus in the period after the accident at the Chernobyl nuclear power plant]. / Perestroiki ret/PTC1 i ret/PTC3r1 v kletkakh raka shchitovidnoi zhelezy, voznikshie u zhitelei Belorussii v period posle avarii na ChAES.

After the accident at the Chernobyl nuclear power plant, a considerable increase in the incidence of thyroid cancer among children in Belarus was observed. In the present study, the frequency of the c-ret protooncogene rearrangements in samples of thyroid carcinomas resected and diagnosed in 1998 from individuals in Belarus was investigated. The ret/PTC1 oncogene was detected in 19% of the samples, and the ret/PTC3r1 oncogene, in 14%. The number of ret/PTC1 rearrangements observed in tumor cells from the patients whose age at the time of the accident was from 1 to 10 years, was greater compared to those whose age at the time was from 10 to 20 years, irrespective of the year of surgery (1996 or 1998). The majority of the patients with ret/PTC3r1 rearrangements lived in Gomel oblast, which was contaminated by the Chernobyl meltdown.