Proteins of the Vesicular Cycle as a Marker of Neuroplasticity of Dopaminergic Neurons in the Substantia Nigra of the Brain

Nigrostriatal dopaminergic neurons (DNs), involved in the regulation of motor function, are characterized by a high plasticity. Indeed, at the death of up to 50% of DNs in Parkinson's disease, the survived neurons provide normal regulation. This study was aimed to determine whether the vesicle cycle proteins, syntaxin Ia (Syn Ia), synaptotagmin I (Syt I), Rab5a, and complexins I and II (Cmpx I and II) are involved in the mechanisms of neuroplasticity in the substantia nigra, which mainly contains cell bodies and processes of the DNs. In the neurotoxic models of Parkinson's disease in mice, it was shown that, at the degeneration of up to 50% of DNs, the content of Syt I, Syn Ia, and Cmpх I and II, involved in vesicle exocytosis, does not change in the substantia nigra as a whole but is compensatorily increased in individual survived DNs. Thus, the data obtained in this study suggest that the impairment of motor behavior, which occurs at the death of half of the nigrostriatal DNs, is not caused by the impairment of the production of vesicle cycle proteins in the survived DNs.

Some Characteristics of Transgenic Clones of Mouse R1 Line Embryonic Stem Cells

Transgenic clones of mouse embryonic stem cells of the RI line were -received by transfection of plasmid linear vectors. The changes in the transgene structure during its integration into the genome of the target cells were investigated. Displacements were found on the flanks of the integrated transgene. It was found that multicopy tandem structures are formed in head- -tail orientation at the transgene integration. It was noted that the number of copies of the integrated transgenes varies considerably, but the introduction of DNA fragments from the nuclear shells into the flanks of the transgene normalizes the number of its copies.

[The peculiarities of defining the psychological and information characteristics of individuals in non-standard situations]

In some situations (e.g. long-duration experiments with human subjects, accidents and catastrophes) assessment of individual's ability to work or even continue functioning by objective criteria may have practical implications. The authors propose complementing the common methods of examination with a number of semantic, self-awareness, associative and symbolic (sign) questionnaires. Thrice-repeated questioning was found to provide adequate results reducing the dispersion of data. The proposed approach was positively validated in an accident and showed good consistency when compared with the objective examination data.

Two variants of the Drosophila melanogaster retrotransposon gypsy (mdg4): structural and functional differences, and distribution in fly stocks

Two variants of the Drosophila melanogaster retrotransposon gypsy were subjected to detailed structural and functional analysis. A series of hybrid constructs containing various combinations of "active" and "inactive" gypsy copies were tested for their ability to produce new DNA copies in cultured cells by means of reverse transcription. It was shown that the previously demonstrated variations in retrotranspositional activity are associated with either one or both of two amino acid substitutions at the beginning of ORF2. The first substitution is located at the boundary between the putative protease and reverse transcriptase domains and, hence, may influence the processing of the polyprotein. The other substitution may alter reverse transcriptase activity since it is located in the second of the seven conserved domains of the RT gene. To address the question of the evolutionary relationship between the two gypsy variants, their distribution was analyzed in among various fly stocks. Southern analysis revealed that all D. melanogaster strains studied so far contain the "inactive" gypsy variant, while the "active" copies are present only in some strains; most of the latter were established from flies recently isolated from natural populations. Finally, in stocks carrying the flamenco mutation the "active" gypsy variant is much more abundant than the "inactive" form. Possible scenarios for the orgin of the "active" form of gypsy are discussed.

The endogenous Drosophila melanogaster retrovirus gypsy can propagate in Drosophila hydei cells

The endogenous Drosophila melanogaster retrovirus gypsy (mdg4) forms virus-like particles (VLPs) which are found as extracellular particles in the medium used to culture D. melanogaster cells. The D. hydei somatic cell line DH14, which does not harbour gypsy sequences, was exposed to D. melanogaster VLPs. Subsequent PCR and Southern analysis revealed that gypsy elements had penetrated into the D. hydei cells, suggesting interspecific transmission of the retrovirus. A D. hydei cell line containing gypsy sequences was established and grown in a mixed culture together with the G418-resistant D. hydei cell line DH33, and gypsy was shown to be transmitted from cell to cell. The proportion of cells carrying gypsy increased with time. The rate of gypsy invasion of the lines DH14 and DH33 was 10(-3) and 10(-2) per cell per generation, respectively. The results demonstrate the possibility of interspecific horizontal transfer of gypsy in the form of its VLPs.

Effects of suramin on PMN interactions with different surfaces

Human polymorphonuclear leukocytes (PMN) were found to tightly adhere on endothelial (lines EAhy926 and ECV304) and collagen surfaces under the influence of the chemotherapeutic drug suramin. This was observed by scanning electron microscopy and quantitated by myeloperoxidase assays. Suramin also inhibited Ca2+ ionophore A23187-stimulated leukotriene (LT) synthesis in PMN interaction with endothelial cells or with collagen surface. Suramin decreased the release of radiolabeled arachidonic acid (AA) and 5-lipoxygenase (5-LO) metabolites by prelabeled PMN stimulated with A23187. Using agents releasing the suramin-stimulated adhesion namely jasplakonolide and dextran sulfate, we observed a reversal of the suramin effect on leukotriene synthesis. Jasplakonolide released the adhesion of PMN on endothelial and collagen-coated surfaces and restored 5-LO activity. Dextran-sulfate released adhesion on collagen-coated surfaces and abolished suramin inhibition. Arachidonate could also overcome adhesion and inhibition of 5-LO. We conclude that suramin-induced tight attachment of PMN on to solid surfaces lead to decreased leukotriene synthesis during subsequent A23187 stimulation in the absence of exogenous substrates.

[The isolation and analysis of lymphoblastoid cell lines from patients with xeroderma pigmentosum and progeria]

Lymphoblastoid cell lines from patients with xeroderma pigmentosum (2 forms) and progeria (unusual form) were established using transformation of peripheral blood lymphocytes by Epstein--Barr virus. The influence of different UV doses on cell vitality, proliferation and cell cycle progression was studied by means of flow cytometry. The cell vitality was determined after incubation of cells with etidium bromide and FDA. We used cytograms with two logarithmic signals (log green/log red) to discriminate the cell cycle status. Cell cultures were used with density of 500,000 cells per 1 ml, previously synchronized at G-phase by the incubation in a medium with low serum content. The effect of UV irradiation was followed during 72 h. Among four analysed cell lines only line XP2SP demonstrated enhanced UV sensitivity, expressed by decreasing of the amount of living cells after the UV dose of 2.5 J/m2 and higher. The cell cycle studies showed that cells were blocked in S-phase and simultaneously the amount of apoptotic cells with both reduced DNA content and ability to bind FDA was seen increased. Similar events were observed in the control line only after the dose of 20 J/m2 and higher.

Two Drosophila retrotransposon gypsy subfamilies differ in ability to produce new DNA copies via reverse transcription in Drosophila cultured cells

Plasmid DNA constructs containing 5' end truncated retrotransposon gypsy were introduced into Drosophila cultured cells. Appearance of new complete DNA copies with reconstructed via reverse transcription 5'LTR were detected by PCR after transient expression and by Southern blot analysis of genome DNA of stably transformed cells. Two gypsy subfamilies supposed to be different in transpositional activity were analyzed in terms of their ability to produce new DNA copies via reverse transcription in D. hydei cultured cells. It was demonstrated that both gypsy variants undergo retrotransposition but with different efficiency.

[Conformation and reduction-oxidation properties of cytochrome c incorporated into reversed micelles of a surfactant in an organic solvent]

Changes observed in CD- and absorption spectra of cytochrome c solubilized in reversed micelles AOT showed significant structural transformations of protein in the region of the active centre and particularly revealed a replacement of the sixth ligand of heme iron. These changes also affected the redox properties of cytochrome c.