Monitoring of tundra vole (Microtus oeconomus Pall.) population inhabiting areas with increased radiation background

The data of complex examinations of morphophysiological state of Tundra vole (Microtus oeconomus Pall.), the lipid peroxidation (LPO) processes and the energy exchange in their organs, the cytogenetic analysis of marrow cells and the process of multiplication in populations inhabiting areas with increased natural radiation background more 50 years are generalized. The data obtained support the existence of qualitative differences of Tundra vole subpopulations inhabiting control and radioactive nuclide contaminating areas. They allow to suppose that the process of adaptation to chronic low intensity radiation effect of Tundra vole in natural conditions involves the transition of the LPO and another regulatory systems to different level of function and is directed on population survival and homeostasis maintenance in changing radioecological conditions.     

Analysis of the functional role in behavior of the neuromediator receptor by antisense knockdown of its gene expression

Now available nucleotide sequences of neurotransmitter receptor genes enable to apply oligonucleotides targeted to mRNAs of these genes for highly selective inactivation of their expression (antisense-knockdown) and for function determination of single receptor subtype by this experimental approach. The antisense-knockdown may be of special importance in case of receptor families members of which are pharmacologically similar. Advantages of the antisense technology for investigation into the brain neurotransmitter receptor function in regulation of behaviour, are discussed.     

Genetical aspects of hormonal modification of the stress reactivity. II. Modification in early ontogenesis of the stress reactivity of adult gray rats selected for behavior toward man

Inherited and modificational changes of the stress reactivity in two outbreed stocks of wild Norway rats trapped in nature and selected for behaviour were studied. During 18 generations the rats of one stock were selected for the lack of defensive behaviour in the glove test (tame), while in another stock the aggressiveness was maintained by the selection (aggressive). Interstock differences in the brain noradrenaline mechanisms were observed. The emotional stress reactivity of the tame animals was decreased, in comparison with the aggressive ones. Definitive stress reactivity of adult rats was modified by injections of hydrocortisone to their mothers on the 16 and 18 days of gestation. Hormonal treatment changed noradrenaline mechanisms and decreased the reaction to emotional stressor in aggressive rats. The modified level of the stress reactivity of aggressive rats was similar to the definitive level of the tame ones. Hormonal treatment did not modify stress reactivity in tame rats. Thus, the phenotype only emerging in aggressive rats, as a result of hormonal modification, is the inherited norm of the tame animals. However, due to rat selection for the lack of defensive behaviour towards the man, high corticosteroid level in the blood of pregnant females, an external developmental factor, in respect to the fetus, loses regulatory function during the development of the neuroendocrine mechanisms of the stress reaction.     

Peptide derivatives of tylosin-related macrolides

Approaches to the synthesis of model compounds based on the tylosin-related macrolides desmycosin and O=mycaminosyltylonolide were developed to study the conformation and topography of the nascent peptide chain in the ribosome tunnel using specially designed peptide derivatives of macrolide antibiotics. A method for selective bromoacetylation of desmycosin at the hydroxyl group of mycinose was developed, which involves preliminary acetylation of mycaminose. The reaction of the 4″-bromoacetyl derivative of the antibiotic with cesium salts of the dipeptide Boc-Ala-Ala-OH and the hexapeptide MeOTr-Gly-Pro-Gly-Pro-Gly-Pro-OH led to the corresponding peptide derivatives of desmycosin. The protected peptides Boc-Ala-Ala-OH, Boc-Ala-Ala-Phe-OH, and Boc-Gly-Pro-Gly-Pro-Gly-Pro-OH were condensed with the C23-hydroxyl group of O-mycaminosyltylonolide.     

Correlation of phospholipid composition and physicochemical characteristics of lipids in tissues of the root vole <Emphasis Type=Italic>Microtus oeconomus</Emphasis> of different ages

There was performed a comparative analysis of phospholipids and of lipid physicochemical characteristics in spleen, blood erythrocytes, and liver of the root voles caught in the natural environmental habitation at different phases of the population cycle, as well of the animals born and raised throughout the entire live in vivarium, depending on the animals’ sex and age. The age-related changes in the phospholipid composition have been established to correlate with lipid physicochemical characteristics, while the scale and direction of the changes depend on the tissue functional role, the initial level of the antioxidative activity (AOA) of its lipids, and sex of the animals. In the process of the organism aging, parameters of the system of regulation of lipid peroxidation change not unidirectionally; in group of animals of the same age, individuals with different biochemical characteristics can be present. Under natural conditions of habitation the degree of expression of age-related changes is modified by populational factors.     

Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Radiation and Environmental Biophysics - This work presents an overview of the applications of retrospective dosimetry techniques in case of incorporation of radionuclides. The fact that internal...     

Characterization of 13 newly isolated strains of anaerobic, cellulolytic, thermophilic bacteria

Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have several positive implications with respect to future development of a transformation system for cellulolytic thermophiles. Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280. Received 12 September 2000/ Accepted in revised form 20 November 2000     

Change of the lipid parameters in the murine liver during one month after low intensity X-ray exposure at low doses

Parameters of the physicochemical regulatory system of lipid peroxidation in the liver of white outbred mice (females) were studied before and during one month after X-ray exposure at the doses less than 1.5 mGy in the autumn and spring-summer seasons. The initial value of parameters is found to exert the most substantial influence on the liver relative mass, the phosphatidylcholine and lysoform relative content in the liver phospholipids of mice. The reliable diminution and the substantial influence of the dose rate dynamics during irradiation are revealed for the molar ratio of [sterols]/[phospholipids], the phosphatidylcholine/phosphatidylethanolamine ratio and the ratio of sums of the more easily oxidizable to the more poorly oxidizable fractions ofphospolipids. The experimental data testify to the complicated nonlinear character of the biological effects of X-irradiation at low doses.     

Identification and characterization of a prevacuolar compartment in stigmas of nicotiana alata

The stigmas of the ornamental tobacco plant Nicotiana alata accumulate large quantities of a series of 6-kD proteinase inhibitors (PIs) in the central vacuole that are derived from a 40-kD precursor protein, Na-PI. The sorting information that directs Na-PI to the vacuole is likely to reside in a C-terminal propeptide domain of 25 amino acids that forms an amphipathic alpha helix. Using cell fractionation techniques, we have examined transit of Na-PI through the endomembrane system and have identified a prevacuolar compartment that contains Na-PI with an intact targeting signal. In contrast, the targeting signal is not present on the predominant form of Na-PI in the vacuole. The prevacuolar compartment is marked by the presence of homologs of both the t-SNARE, PEP12p, and the putative vacuolar sorting receptor BP-80. Cross-linking and affinity precipitation studies revealed that Na-PI associates with BP-80 within this compartment, providing in vivo evidence for the function of BP-80 as a sorting receptor for a protein with a C-terminal vacuolar targeting signal.     

New fluorescent macrolide derivatives for studying interactions of antibiotics and their analogs with the ribosomal exit tunnel

Novel fluorescent derivatives of macrolide antibiotics related to tylosin bearing rhodamine, fluorescein, Alexa Fluor 488, BODIPY FL, and nitrobenzoxadiazole (NBD) residues were synthesized. The formation of complexes of these compounds with 70S E. coli ribosomes was studied by measuring the fluorescence polarization depending on the ribosome amount at constant concentration of the fluorescent substance. With the synthesized fluorescent tylosin derivatives, the dissociation constants for ribosome complexes with several known antibiotics and macrolide analogs previously obtained were determined. It was found that the fluorescent tylosin derivatives containing BODIPY FL and NBD groups could be used to screen the binding of novel antibiotics to bacterial ribosomes in the macrolide-binding site.