Violation of the law of uniformity of the first generation of hybrids

Variability was revealed in the isozyme spectra in the seed progeny from crosses of two beet plants homozygous for contrasting alleles of marker enzyme loci.     

c-DNA Microarray to determine molecular events in neurodegeneration and neuroprotection

Methamphetamine (METH) is a neurotoxic drug of abuse that can cause terminal degeneration. Our laboratory recently showed that METH can also cause widespread apoptosis in the rodent brain. Current concepts of the molecular neurotoxicity of this illicit substance have earlier suggested the participation of reactive oxygen species, inflammatory processes and immediate early genes. Recent cDNA studies in our laboratory have hinted to the possibility that METH-induced neurodegeneration might also include the participation of cell death might also include the participation of cell death genes such as BAX and BCL-2. Activation of multiple caspases appears to also occur during METH-induced neurodegeneration. Furthermore, DNA repair pathways seem to also be involved in attempts to protect against METH-induced DNA damage. These results will be discussed in terms of the possible involvement of multiple transduction mechanisms in the appearance of METH neurotoxicity.     

Inhibiting β-secretase activity in Alzheimer's disease cell models with single-chain antibodies specifically targeting APP

The Amyloid-β (Aβ) peptide is produced from the amyloid precursor protein (APP) by sequential proteolytic cleavage of APP first by β-secretase and then by γ-secretase. β-Site APP cleaving enzyme-1 (BACE-1) is the predominant enzyme involved in β-secretase processing of APP and is a primary therapeutic target for treatment of Alzheimer's disease. While inhibiting BACE-1 activity has obvious therapeutic advantages, BACE-1 also cleaves numerous other substrates with important physiological activity. Thus, blanket inhibition of BACE-1 function may have adverse side effects. We isolated a single chain variable fragment (scFv) from a human-based scFv yeast display library that selectively inhibits BACE-1 activity toward APP by binding the APP substrate at the proteolytic site. We selected the iBSEC1 scFv, since it recognizes the BACE-1 cleavage site on APP but does not bind the adjacent highly antigenic N-terminal of Aβ, and thus it will target APP but not soluble Aβ. When added to 7PA2 cells, a mammalian cell line that overexpresses APP, the iBSEC1 scFv binds APP on the cell surface, reduces toxicity induced by APP overexpression, and reduces both intracellular and extracellular Aβ levels by around 50%. Since the iBSEC1 scFv does not contain the antibody F_c region, this construct does not pose the risk of exacerbating inflammation in the brain as faced with full-length monoclonal antibodies for potential therapeutic applications.     

Molecular differences in Adh1-F and Adh1-S alleles in the sugar beet Beta vulgaris L

We compared nucleotide sequences of exon 4 and part of exon 5 of alleles F and S of the Adh1 locus controlling alcohol dehydrogenase in sugar beet. The Adh1-F and Adh1-S sequences of the examined fragment were shown to differ by two nucleotides. Adenine (A) and cytosine (C) of Adh1-F were substituted by respectively thymine (T) and adenine (A) in Adh1-S. Consequently, glutamine and asparagine from the F subunit of ADH1 are replaced by valine and lysine, respectively. Because of differences in the amino acid content, the F subunit is by two elementary charges more negatively charged electrically than the S subunit, which correlates with differences in their electrophoretic mobility. Comparison of the examined Adh1 fragment of sugar beet with its counterparts in other plants showed that the sites bearing substitutions in the former species are classed as variable.     

Subcellular localization of isozymes of NAD-dependent malate dehydrogenase in sugar beet <Emphasis Type="Italic">Beta vulgaris</Emphasis> L.

Subcellular localization of isozymes of NAD-dependent malate dehydrogenase (MDH) in sugar beet was studied. Isozymes ss and ll controlled by loci Mdh2 and Mdh3, respectively, were shown to locate in mitochondria, whereas isozyme pp controlled by locus Mdh1, in microbodies. All examined samples lack hybrid MDH isozymes, which could testify to the interaction between products of nonallelic Mdh genes. This can be explained by the localization of nonallelic isozymes in various compartments of the cell and organelles.     

Molecular Differences between Alleles Adh1-F and Adh1-Sin Sugar Beet Beta vulgaris L.

We compared nucleotide sequences of exon 4 and part of exon 5 of alleles F and S of the Adh1 locus controlling alcohol dehydrogenase in sugar beet. The Adh1-F and Adh1-S sequences of the examined fragment were shown to differ by two nucleotides. Adenine (A) and cytosine (C) of Adh1-F were substituted by respectively thymine (T) and adenine (A) in Adh1-S. Consequently, glutamine and asparagine from the F subunit of ADH1 are replaced by valine and lysine, respectively. Because of differences in the amino acid content, the F subunit is by two elementary charges more negatively charged electrically than the S subunit, which correlates with differences in their electrophoretic mobility. Comparison of the examined Adh1 fragment of sugar beet with its counterparts in other plants showed that the sites bearing substitutions in the former species are classed as variable.     

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.     

Autosegregation of enzyme loci in agamospermous progenies of triploid plants of sugar beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.)

The ratios of the phenotypic classes of glucosephosphate isomerase (GPI2) and malate dehydrogenase (MDH1 and MDH2) were studied in agamospermous progenies of triploid sugar beet plants. The ratio of the phenotypic classes of these enzymes corresponds to the calculations based on the assumption of polyteny of chromosomes carrying alleles of the enzyme loci accompanied by the loss of extra copies of the alleles in the first division of a cell entering embryogenesis. An increase in the gene dosage due to polyteny leads to the appearance in the progeny with a definite frequency of alleles that were absent in the original parental plant. The notions of “meiotic autosegregation” and “mitotic autosegregation” characteristic of meiotic and mitotic agamospermy are introduced, as well as the term locus polygenotype characterizing not only the allelic composition and the number of chromosomes, but also the number of chromatids carrying alleles of the marker locus in the cell before its entry into embryogenesis.     

Marker traits of variability induced in <Emphasis Type="Italic">Triticum aestivum</Emphasis> L. by nicotinic acid

A search for markers of epigenetic variability in spring common wheat form Genotroph-1, obtained after the treatment of seeds and growing plants of spring common wheat cultivar Kazakhstanskaya-126 with nicotinic acid of innate origin (0.1–0.01% water solutions), and in a winter wheat line Gostianum-88 along with a common wheat cultivar Alem obtained on the basis of Genotroph-1 was conducted under laboratory conditions. The possibility of using isoenzymes as markers for studying variability induced by natural nicotinic acid with high frequency was demonstrated. The marker enzyme glutamate oxaloacetate transaminase-2, by which modified plants and lines obtained on the basis of these plants differ from the original cultivar, was identified.