Behavior in the forced-swimming test and expression of BDNF and Bcl-xl genes in the rat brain

A single exposure of rats to the forced-swimming stress decreased BDNF mRNA levels in the cortex and increased Bcl-xl gene expression in the hippocampus and amygdala 24 h after the stress. The animals demonstrated a depressive-like behavior and elevated blood corticosterone level. There was a significant negative correlation between BDNF mRNA level in the cortex and immobility time during swimming. Repeated exposure to swimming stress caused the elevation of the hippocampal BDNF mRNA level assessed 24 h after the second swimming session. The data suggest that stress-induced down-regulation of cortical BDNF gene expression and behavioral despair in the forced-swimming test may be interrelated. The increase in the BDNF and Bcl-xl mRNA levels may contribute to the mechanisms protecting the brain against negative effects of stress.     

Development of a colorimetric test system for detection of point mutations via ligation of a tandem of short oligonucleotides on methacrylate beads

A new approach for detection of point mutations has been developed. The nonradioactive test system proposed is based on enzymatic ligation of a tandem of three short oligonucleotides B∼pN₈+pN₄+pN′₈ Bio in the presence of a complementary DNA template. The 5′-terminal octanucleotide B∼pN₈ is immobilized on polymer methacrylate beads (B) and the 3′-terminal octanucleotide pN′₈ Bio contains a biotin residue at the 3′-phosphate. Ligation of the tandem produces a 20-mer biotinylated oligonucleotide on a polymer bead, which is then visualized via subsequent treatments with streptavidin-alkaline phosphatase conjugate and chromogenic substrates. Intense staining of the polymer beads is observed when the amount of DNA template (20-mer oligonucleotide) is as low as ∼10⁻¹⁴ mol. It is shown that practically no polymer staining is observed when the complex formed by the tandem and the 20-mer DNA template contains a mismatch either in the tetranucleotide duplex or in the duplex of octanucleotide immobilized on the beads. This suggests a possibility of using the presented approach in test systems for detection of point mutations in PCR-amplified DNA fragments.     

Detection of Single-Base Substitutions in Amplified Fragments via Ligation of a Tandem of Short Oligonucleotides in Solution and on a Solid Carrier

Ligation of a tandem of short oligonucleotides was proposed for detecting single-base substitutions in amplified DNA fragments. An octamer–tetramer–octamer tandem was ligated on a 20-mer template with T4 DNA ligase. As shown with radiolabeled oligonucleotides, the efficiency and selectivity of ligation did not change with an octamer linked to a water-soluble carrier based on polyethylene glycol (MPEG), while ligation was somewhat lower with the octamer immobilized on methacrylate beads (DMEG). In both cases, polymer attachment improved the discrimination of 20-mer templates with single-base substitutions in the binding site for the tetramer or for the immobilized octamer. Tandems with a radiolabeled or biotinylated component were also efficiently ligated on amplified DNA fragments. The data obtained with DNA fragments of HIV-1 strains bru and rf demonstrate the possibility of reliable detection of single-base substitutions via ligation of a tandem and colorimetric detection of the immobilized ligation product with the streptavidin–alkaline phosphatase technique.     

Anti-Apoptotic Protein Bcl-xL Expression in the Midbrain Raphe Region Is Sensitive to Stress and Glucocorticoids

Anti-apoptotic proteins are suggested to be important for the normal health of neurons and synapses as well as for resilience to stress. In order to determine whether stressful events may influence the expression of anti-apoptotic protein Bcl-xL in the midbrain and specifically in the midbrain serotonergic (5-HT) neurons involved in neurobehavioral responses to adverse stimuli, adult male rats were subjected to short-term or chronic forced swim stress. A short-term stress rapidly increased the midbrain bcl-xl mRNA levels and significantly elevated Bcl-xL immunoreactivity in the midbrain 5-HT cells. Stress-induced increase in glucocorticoid secretion was implicated in the observed effect. The levels of bcl-xl mRNA were decreased after stress when glucocorticoid elevation was inhibited by metyrapone (MET, 150 mg/kg), and this decrease was attenuated by glucocorticoid replacement with dexamethasone (DEX; 0.2 mg/kg). Both short-term stress and acute DEX administration, in parallel with Bcl-xL, caused a significant increase in tph2 mRNA levels and slightly enhanced tryptophan hydroxylase immunoreactivity in the midbrain. The increasing effect on the bcl-xl expression was specific to the short-term stress. Forced swim repeated daily for 2 weeks led to a decrease in bcl-xl mRNA in the midbrain without any effects on the Bcl-xL protein expression in the 5-HT neurons. In chronically stressed animals, an increase in tph2 gene expression was not associated with any changes in tryptophan hydroxylase protein levels. Our findings are the first to demonstrate that both short-term stress and acute glucocorticoid exposures induce Bcl-xL protein expression in the midbrain 5-HT neurons concomitantly with the activation of the 5-HT synthesis pathway in these neurons.     

Evolution of <Emphasis Type="Italic">Triticum aethiopicum</Emphasis> Jakubz. from the Position of Chromosome Analysis

Cytogenetic analysis was conducted on a set of 67 Ethiopian wheat accessions collected by the expedition of N.I. Vavilov in 1927 and 85 years later by the Joint Ethiopian–Russian Biological Expedition (JERBE) in 2012 in the same sites of Ethiopia. The preservation of the polymorphism system of heterochromatic chromosome sites upon the change in the Ethiopian wheat population structure over the past period owing to a frequency shift of some specific chromosome variants and an increase in the proportion of genotypes carrying marker rearrangements was demonstrated. The unevenness of the geographical distribution of the 2A:4B translocation and of the 5A inversion was identified, and it was demonstrated that wheat accessions from Eritrea were cytogenetically the most isolated from the population from the central regions of Ethiopia. A low level of the Ethiopian wheat polymorphism was found along with the prevalence of the same chromosome rearrangement variants, which was indicative of monophyletic origin of the species. It was suggested that Triticum aethiopicum could have diverged from Ethiopian emmer as a result of hybridization with other wheat species, while subsequent evolution of these species occurred independently. Evidence for the participation of Ethiopian wheat in the formation of the gene pool of the unique Moroccan group of T. dicoccum was obtained.     

Fish in the diet of the Long-eared Owl Asio otus

Capsule: Analysis of regurgitated pellets showed that fish were a very rare prey in the diet of the Long-eared Owl Asio otus. Remains of 38 individual fish were found at 8 of 121 nests and only in 2 out of 11 years. Occurrence tended to be more frequent in warm dry periods, when water ditches were dry.     

Interaction of chloramphenicol tripeptide analogs with ribosomes

Chloramphenicol amine peptide derivatives containing tripeptide fragments of regulatory “stop peptides”–MRL, IRA, IWP–were synthesized. The ability of the compounds to form ribosomal complexes was studied by displacement of the fluorescent erythromycin analog from its complex with E. coli ribosomes. It was found that peptide chloramphenicol analogs are able to bind to bacterial ribosomes. The dissociation constants were 4.3-10 μM, which is 100-fold lower than the corresponding values for chloramphenicol amine–ribosome complex. Interaction of the chloramphenicol peptide analogs with ribosomes was simulated by molecular docking, and the most probable contacts of “stop peptide” motifs with the elements of nascent peptide exit tunnel were identified.     

Genes, hormones and the risk factors in the development of the male phenotype]

The onset of the expression of Sry and other sex-determining genes such as SF-1, DAX-1, WT-1 and SOX family initiates the testis organogenesis from the bipotential primordium. The fetal testis produces anti-Mullerian hormone and testosterone. These two hormones play essential role in the further development of the male phenotype. The bases for the activity of the sexual function and behavior are created within frames of these processes. Interindividual differences in these characters may achieve high degrees. Alleles of the sex-determining genes and the genes of the other genetic systems which participate in regulation of reproduction may be responsible for this variability. For example, the inherited variations in testosterone levels in the blood are negatively correlated to the alpha2-adrenergic receptor densities in the hypothalamus in males of mouse strains. Testosterone level in the fetal blood during critical period of sexual differentiation is one of the key points through which genetic and ontogenetic factors affect male sexual development. We have found nearly twofold interstrain differences in testosterone levels in the blood of male rat fetuses of 2 strains. The rats with higher testosterone levels during intrauterine development have higher rates of sexual maturation and sexual activity in future life. Genetic differences were also found in sensitivity of fetal testosterone to disruptive influences. These differences may be the reason for the strain-specific effects of prenatal stress or glucocorticoid treatment on the male sexual development in rats and mice. Substances and treatments which are capable of changing testosterone levels and/or interaction of these hormones with their receptors: ionizing radiation, pesticides, xenoestrogenes, drugs, alcohol, various stressors are the risk factors of the male sexual development.     

Effect of hydrophobicity of yeast cell envelope on the rate of autooxidation of methyloleate

The relationships between the antioxidant and antiperoxide properties and the lipid composition of yeast cell envelope prior to, and after the reaction with a liquid culture medium were studied. Correlations between the hydrophobicity of envelopes, their lipid composition and the parameters of the kinetic curves of the oxidation of model methyloleate in the presence of lipids were established. It was found that, irrespective of the general content of lipids in yeast cell envelope, preparations with high antiperoxide activity of lipids had a high hydrophobicity and sorbed lipophilic prooxidants from medium, whereas preparations with low antiperoxide activity were less hydrophobic and adsorbed predominantly lipophilic inhibitors. It was found that the most comprehensive information on the physicochemical properties of lipids adsorbed from medium is provided by an analysis of kinetic curves of oxidation in toto.