The Intermetallic Semiconductor -IrGa: a Material in the State.

The compound IrGa was synthesized by direct reaction of the elements. It is formed as a high-temperature phase in the Ir-Ga system. Single-crystal X-ray diffraction analysis confirms the tetragonal symmetry (space group 4 , No.

In Situ Observation of Electron-Beam-Induced Formation of Nano-Structures in PbTe.

Nano-scaled thermoelectric materials attract significant interest due to their improved physical properties as compared to bulk materials. Well-shaped nanoparticles such as nano-bars and nano-cubes were observed in the known thermoelectric material PbTe. Their extended two-dimensional nano-layer arrangements form directly in situ through electron-beam treatment in the transmission electron microscope.

In Situ Growth and Size Regulation of Single Gold Nanoparticles in Composite Microgels.

Herein, a novel method for the in situ growth of single gold nanoparticles (AuNPs) in microgel (MG) networks is presented. The key feature in this approach is the localization of β-diketone groups capable of both complexation and reduction of aurate ions in the MGs' core, which allows localization of the nucleation and growth of single AuNPs. The MG synthesis is carried out via precipitation polymerization in water with N-vinylcaprolactam as the main monomer and with the two comonomers acetoacetoxyethyl methacrylate (AAEM) and acrylic acid (AAc), where AAEM is mainly located in the MGs' core and AAc in their shell.

Tracking aluminium impurities in single crystals of the heavy-fermion superconductor UBe.

The influence of Al incorporation on the heavy fermion superconductor UBe was investigated to explain the sample dependence of physical properties. Clear evidence for incorporated Al in flux-grown UBe single crystals is presented by results from X-ray diffraction, nuclear magnetic resonance and X-ray spectroscopy. The increase of the lattice parameter and the concomitant change of the superconducting properties are caused by substitution of Be in the compound by 1-2 at.

[Effect of Ultrasmall Gold Nanoparticles on the Murine Native Sperm Chromatin].

The effects of ultrasmall (2-3 nm) gold nanoparticles on native epididymal sperm chromatin of CBAxC57BL/6 hybrid mice and 129/IMG mice with a mutation in the DNA-polymerase iota gene were studied. It is shown that for both mouse strains after sperm incubation in a solution containing Au nanoparticles, at 23, 37 and 60 degrees C for 30 min followed by 1 hour treatment in dithiothreitol solution, a decrease in the number of nuclei with fully decondensed chromatin was observed compared with the control. Though, the manifestation of this effect in the population of 129/IMG mice mature sperm, was weaker.

[Bovine sperm chromatin is not protected from the effects ultrasmall gold nanoparticles].

The response of ejaculated bovine spermatozoa to gold nanoparticles was studied by the standard method of nuclear chromatin decondensation in vitro. After the treatment of semen samples with a hydrosol containing gold nanoparticles with an average diameter of 3.0 nm and a concentration of 1 x 10(15) particles/mL, the ability of sperm nuclei to decondense in the presence of sodium dodecyl sulfate (SDS) and dithiothreitol (DTT) dramatically changed compared to the control.

[Effect of gold nanoparticles on mouse spermatogenesis].

The response of the mouse male germ cells exposed to gold nanoparticles (approximately 2.5 nm) was studied. Our investigation demonstrates that treatment with Au nanoparticles for four days does not impair the architecture of the spermatogenic epithelium.

[Advanced approaches to studying the population diversity of marine fishes: new opportunities for fisheries control and management].

Recent conceptual and technological advances now enable fisheries geneticists to detect and monitor the dynamics and distribution of marine fish populations more effectively than ever before. Information on the extent of genetically-based divergence among populations, so-called "population diversity", is crucial in the quest to manage exploited living resources sustainably since it endows evolutionary potential in the face of environmental change. The generally limited dialogue between scientists, fisheries managers and policy makers, however, continues to constrain integration of population genetic data into tangible policy applications.

[Estimation of the frequencies of induced mutations in spermatogenic cells of senescence-accelerated prone mice of the SAMP1 strain].

The results obtained in this work demonstrate the dynamics of cytogenetic changes of spermatogenic cells in senescence-accelerated prone mice, strain SAMP1, after a single exposure to a chemical mutagen, dipin, at a genetically active dose of 30 mg/kg. In the time interval between days 3 and 28 the frequency of induced spermatogonial micronuclei does not significantly exceed the level of spontaneous mutagenesis. The lack of an experimental effect of micronuclei in this time interval is probably a consequence of mitotic delay and (or) of the death of a considerable part of genetically defective cells in the spermatogonial compartment.

[Analysis of spermatogenesis in senescence-accelerated mice].

A comparative analysis of age-related dynamics of spermatogenesis has been performed in mutant mouse lines predisposed or resistant to accelerated senescence (SAMP1 and SAMR1 respectively). The results show that quantitative and morphohistological trends in the development of sperm cells and Sertoli cells in both lines are similar in both lines. Their comparison with data obtained in our previous studies (Zakhidov et al.

[Hereditary muscular dystrophy: bioengineering approaches to muscle fiber repair].

Restoration of disturbed functions of the organs and tissues is the main task of contemporary genetic and cellular biotechnology, including genetic and cellular therapy. Duchenne dystrophy, one of the most widespread human genetic diseases, is at the same time the most extensively studied from the viewpoint of both genetic and histological changes leading to muscle fiber degeneration. Although many studies carried out on models, recognized analogous to Duchenne dystrophy, gave hopeful results, clinical tests with the use of developed methods gave no expected success and the rate of mortality from this disease amounts to 100%.

[The BCL-xL and ACR-1 genes promote differentiation and reduce apoptosis in muscle fibers of mdx mice].

The effects of the human BCL-xL and ACR-1 genes on dystrophin expression in cross-striated muscle fibers (CSMF) and on CSMF viability were studied in mdx mice after ballistic cotransfection with the human dystrophin minigene. In control mice, the proportion of dystrophin-positive (D(+)) and dying CSMF were 2.1 +/- 0.

[Gene hACR-1 suppresses apoptosis of striated muscle fibres of m. quadriceps femoris after ballistic transfection of mdx mice].

Human minidystrophin gene (pSG5dys plasmid) and hACR-1 gene (pRc-CMV-10.1 plasmid) were cotransfected by means of "gene-gun" to M. quadriceps femoris of mdx mice.

The quantitative characteristics of efficiency of ballistic transfection of chimeric antibody genes.

A quantitative approach was applied to the study of in vivo expression of foreign genes introduced into mice by ballistic transfection. Because in some cases one must take into account both the level of synthesized protein and that of antibodies to it, we derived the equation which allows to calculate the exact quantity of both proteins. This formula was applied to in vivo expression of a chimeric (human/mice) immunoglobulin E gene.

[Activity of exogenous genetic designs, introduced into cells by a ballistic transfection method, in murine ontogenesis].

We used the method of particle bombardment (ballistic transfection) to introduce beta-galactosidase and human dystrophin genes into mouse embryos and skeletal muscles of adult mice. We examined the mechanisms of DNA transfer into skeletal muscle cells, the biological processes accompanying and following this transfer, the susceptibility of various types of muscle cells to transfection, and the duration of expression of and conditions affecting the introduced genes. We have also developed an effective, convenient, and practical methods of skeletal muscles transfection.

[Expression of the human dystrophin gene in mdx mouse skeletal muscles after ballistic transfection].

"Gene-gun" ballistic transfection (BT) was used to deliver genetic constructs pMLVDy and pHSADy containing full-length cDNA of the dystrophin gene to musculus quadriceps remoris and musculus gluteus of mdx mice, which represent a natural model of Duchenne muscular dystrophy. Clusters of dystrophin-positive muscular fibers (DPMF) were immunocytochemically detected in sites exposed to BT. The average number of DPMF was 2% by the 17th day and 3% by the 60th day after BT with pMLVDy, whereas the number of revertant DPMF was 0.

[Differentiation of muscle fibers in mdx mice after ballistic transfection of cDNA of the human dystrophin gene].

Changes in morphological dimensions of MDX mouse myofibres in M. rectus femoris were recorded after ballistic transfection (BT) with pHSADys and pVMMDys plasmids containing cDNA of the full-length human dystrophin gene. The dystrophin expression was observed by an immunomorphological procedure with P6 antibody and PAP method.

Bacterial beta-galactosidase and human dystrophin genes are expressed in mouse skeletal muscle fibers after ballistic transfection.

Ballistic transfection, based on cell and tissue bombardment by the tungsten and gold microparticles covered with the gene DNA, was used for the delivery of a bacterial beta-galactosidase and a full-length cDNA copy of the human dystrophin genes into mouse skeletal muscles. CMV-lacZ, SV40-lacZ, LTR-lacZneo and full-length cDNA dystrophin (pDMD-1, approximately 16 kb) in eukaryotic expression vector pJ OMEGA driven by mouse leukaemia virus promotor (pMLVDy) were used throughout the studies. Musculus glutaeus superficialis of C57BL/6J and quadriceps femoris of mdx male mice were opened surgically under anesthesia and bombarded by means of the gene-gun technique originally developed by us.

[Metallonucleoliposome complexes as a vehicle for gene delivery to mouse skeletal muscles in vivo].

A simple new method for preparing plasmid DNA and preformed zwitterionic liposome complexes is proposed. The ability of these metallonucleoliposome complexes to serve as a vehicle for gene delivery to mammalian cells in vivo was studied. A high level of expression of the reporter gene introduced was observed in mouse skeletal muscles in vivo.

[The ballistic transfection of mammalian cells in vivo].

The method of ballistic transfection initially proposed for genetic transformation of plants was used for animal cells in vitro and in situ. The method consists in bombarding the transfected cells with microparticles of heavy metals carrying foreign DNA. Having penetrated in the cell nucleus, the microparticles transport the introduced gene.

Transfer of foreign DNA into the cells of developing mouse embryos by microprojectile bombardment.

Mouse cells of developing embryos at the 2-4 cell, morula and blastocyst stages, were bombarded by high velocity tungsten microprojectiles. About 70% of developing embryos survived the bombardment. The general embryo structure did not change as a result of the bombardment.

[Use of high velocity mechanical injection for the transfer of foreign DNA into early mouse embryos].

The possibility of high velocity mechanical transfer of foreign DNA into inner cell mass of mouse blastocyst was shown. Penetration of tungsten microparticles into early embryo cell nuclei and their localization on mitotic chromosomes was demonstrated. About 70% of developing embryos survived the bombardment.

The delivery of foreign genes into fertilized fish eggs using high-velocity microprojectiles.

Fertilized eggs of loach (Misgurnus fossilis), rainbow trout (Salmo gairdneri) and zebrafish (Brachydanio rerio) were bombarded with high-velocity tungsten microprojectiles covered with plasmid DNA containing sequences of beta-galactosidase and neomycin phosphotransferase genes. About 70% of the eggs survived the bombardment. The activity of both transferred genes was revealed in the fish developed from the bombarded eggs.