T-specific D17Leh66 DNA elements in family Muridae

Blot-hybridization analysis with the use of the t-specific probe D17Leh66 has been used to study DNA of various representatives of family Muridae. Hamsters from genus Phodopus have no homologs of this probe, whereas African rats from genus Lophuromys have some homologous elements. This indicates that sequence Dl7Leh66 is ancient and was probably present in the common ancestor of family Muridae.     

Modelling of long-term radionuclide migration in a non-running fresh-water reservoir

A mathematical model is presented for radionuclide migration in a non-running fresh-water reservoir that takes into account removal of microimpurities from water as a result of both molecular and ion exchange sorption at the bottom sediments water interface and detritus formation. The model was tested for sensitivity to precisely estimate experimental parameters. The test showed that the model is universal. Prediction was made of reduction in water of 137Cs and 90Sr contents and distribution of these radionuclides in the water body affected by the accident at the "Mayak" chemical plant.     

Optimization of conditions for transformation of maleic acid by immobilized cells of Alcaligenes xylosoxidans subspecies xylosoxidans 260

Immobilized cells of Alcaligenes xylosoxidans subsp. xylosoxidans 260 used 98% of maleic acid (initial concentration of 5.0 g/l medium) in periodic conditions for 48 h. Free cells transformed only 26% of substrate in 96 h. Immobilized cells of a selected S-variant of A. xylosoxidans used maleate (30.0 g/l) entirely in 96 h during periodic cultivation and only 15.0 g/l of maleate in continuous cultivation at a flow rate of 0.03 h-1.     

Features of the modulating effect of complexes of ribosome-inactivating proteins type II with sugars on respiratory burst of neturophils, caused by a chemotactic peptide

It was shown that agents inducing phagocytosis (zymosan, lectins) cause changes in the number of receptors responsible for fast neutrophil reaction (chemotaxis or respiratory burst) or inhibit the binding of the agonist to its receptor. Among lectins are ribosome-inactivating proteins of type II ricin and agglutinin ricin, which penetrate the cell by binding to mannose and galactose receptors. It was shown that ribosome-inactivating proteins of type II can exhibit the properties of the antagonist of the receptor N-formylmethionylleucylphenylalanine. Ricin is more effective in modulating the respiratory burst induced by the chemotactic peptide than agglutinin ricin. The modulating effect of ribosome-inactivating proteins of type II on neutrophils is likely to be mediated by their interaction with galactose rather than mannose receptors. Presumably, the affinity of ribosome-inactivating proteins to galactose receptors increases with increasing amount of saccharides bound to the protein molecule. The modulating effect of ribosome-inactivating proteins of type II on the respiratory burst of neutrophils induced the chemotactic peptide is due to the structural peculiarities of these proteins.     

Characterization of plant growth promoting rhizobacteria isolated from polluted soils and containing 1-aminocyclopropane-1-carboxylate deaminase

Fifteen bacterial strains containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase were isolated from the rhizoplane of pea (Pisum sativum L.) and Indian mustard (Brassica juncea L.) grown in different soils and a long-standing sewage sludge contaminated with heavy metals. The isolated strains were characterized and assigned to various genera and species, such as Pseudomonas brassicacearum, Pseudomonas marginalis, Pseudomonas oryzihabitans, Pseudomonas putida, Pseudomonas sp., Alcaligenes xylosoxidans, Alcaligenes sp., Variovorax paradoxus, Bacillus pumilus, and Rhodococcus sp. by determination of 16S rRNA gene sequences. The root elongation of Indian mustard and rape (Brassica napus var. oleifera L.) germinating seedlings was stimulated by inoculation with 8 and 13 isolated strains, respectively. The bacteria were tolerant to cadmium toxicity and stimulated root elongation of rape seedlings in the presence of 300 microM CdCl2 in the nutrient solution. The effect of ACC-utilising bacteria on root elongation correlated with the impact of aminoethoxyvinylglycine and silver ions, chemical inhibitors of ethylene biosynthesis. A significant improvement in the growth of rape caused by inoculation with certain selected strains was also observed in pot experiments, when the plants were cultivated in cadmium-supplemented soil. The biomass of pea cv. Sparkle and its ethylene sensitive mutant E2 (sym5), in particular, was increased through inoculation with certain strains of ACC-utilising bacteria in pot experiments in quartz sand culture. The beneficial effect of the bacteria on plant growth varied significantly depending on individual bacterial strains, plant genotype, and growth conditions. The results suggest that plant growth promoting rhizobacteria containing ACC deaminase are present in various soils and offer promise as a bacterial inoculum for improvement of plant growth, particularly under unfavourable environmental conditions.     

Small G-proteins Ras,Rac and Rho in the regulation of the neutrophil respiratory burst induced by formyl peptide

Formylated peptides specifically activate many of the neutrophil functions; their action is mediated via formyl peptide receptors (FPRs). FPRs belong to the family of receptors having seven transmembrane-spanning domains and coupled with G-proteins (GPCR). About a dozen of highly homologous genes of FPRs were found to be localized in mouse chromosome 17. By binding with labeled N-formyl-Met-Leu-Phe (fMLF), FPRs are classified as receptors with high (FPR1) and low (FPR2 and FPR3/FPRL1) affinity to formyl peptide. Binding of formyl peptide with FPRs triggers the complex signaling events, the most studied are: activation of phospholipase C (PLC) with subsequent calcium signaling; launching of mitogen activated protein kinases (MAPKs) cascade pathway, and activation of phosphoinositol-3-kinase (PI3K) cascades. As we have shown previously, the priming of the respiratory burst of mice neutrophils occurs under the cell activation by fMLF in high doses only, i.e., it is necessary to activate low affinity FPRs. Besides, the usage of the specific MEK and p38MAPK inhibitors induced significant suppression of the response to 1 μM fMLM, while the response to 50 μM fMLF increased in the presence of the inhibitors. We suggest that there is a signal divergence upon activation of high and low affinity fMLF receptors, and small G protein dependent signaling pathways could be alternative to activate NADPH oxidase. Here we demonstrate that Ras-proteins participate in the respiratory burst activation, especially in activation via the high affinity fMLF receptors. Activation of the Rho- and Rac-proteins induced the down-regulation of the respiratory burst under the stimulation of high affinity FPRs. The inhibition of the Rho-proteins almost completely suppressed the respiratory burst activated via the high and low affinity receptors, probably due to inability to assemble of the cytoskeleton proteins and NADPH oxidase components.     

Presence of a novel 16S-23S rRNA gene intergenic spacer insert in Bradyrhizobium canariense strains

Seven slow-growing bacterial strains isolated from root nodules of yellow serradella (Ornithopus compressus) that originated from Asinara Island on North Western Sardinia in Italy were characterized by partial 16S rRNA gene and intergenic spacer (ITS) sequencing as well as amplified fragment length polymorphism (AFLP) genomic fingerprinting. The results indicated that the O. compressus isolates belong to the Bradyrhizobium canariense species. The analysis of ITS sequences divided the branch of B. canariense strains into two statistically separated groups (ITS clusters I and II). All the strains in ITS cluster I showed the presence of unique oligonucleotide insert TTAGAGACTTAGGTTTCTK. This insert was neither found in other described species of the family Rhizobiaceae nor in any other bacterial families and can be used as a natural and high selective genetic marker for ITS cluster I of B. canariense strains. ITS grouping of O. compressus isolates was supported by the unweighted pair group method with arithmetic averages cluster analysis of their AFLP patterns, suggesting that the strains of ITS cluster II were genetically closer to each other than to isolates from the ITS cluster I. A taxonomic importance is supposed of the revealed 19 bp ITS insert for an intraspecific division within high heterogeneous B. canariense species.     

Metaphase and meiotic chromosomes,synaptonemal complexes (SC) of the lizard <Emphasis Type="Italic">Zootoca vivipara</Emphasis>

Somatic mitotic and meiotic chromosomes at the pachytene and at the metaphase I of the males of the viviparous lizard, Zootoca vivipara (Lichtenstein, 1823), from northwestern Russia, belonging to the Russian form of Z. v. vivipara, are examined. The spreading of synaptonemal complexes (SC) of their chromosomes are obtained and analyzed for the first time. Eighteen SC are observed, including SC of the Z₁Z₁ (pairs 5 or 6) and the Z₂Z₂ (pair 13) sex chromosomes. Characteristics of SC are compared with the number and the shape of bivalents and with those of the karyotype structure. In the studied Russian form of Z. v. vivipara, the length ratios of bivalents correlate with that of mitotic chromosomes (2n = 36); however, some specificity in the morphology of SC of the Z₁Z₁ sex chromosomes is reported in this article.     

Evaluation of phylogenetic relationships in the genus <Emphasis Type="Italic">Mus</Emphasis> using <Emphasis Type="Italic">t</Emphasis>-specific microsatellite DNA markers

The t-complex includes a complex system of genes localized in the proximal region of chromosome 17 of house mouse Mus musculus. The results of microsatellite analysis of laboratory stocks of house mice carrying t ¹², t ^w5, t ^w12, and t ^w73 haplotypes and wild mice from natural populations of Russia (Volgograd, Rostov, Saratov oblasts, and Kalmykia), Armenia, Bulgaria, Iran, and Mongolia performed by the PCR method with the use of eight pairs of D17Mit primers (16, 21, 23, 28, 32, 57, 63, 78) are presented. These pairs of primers amplify microsatellite DNA sequences on mouse chromosome 17 in the region from 7.6 to 18.8 cM that correspond to inversions (In (17) 3.4). Each pair of primers recognized three to six variants of nucleotide sequences ranging in size from 90–120 bp (D17Mit 16) to 300–330 bp (D17Mit 57). In most cases, two variants of nucleotide sequences were detected in each individual, i. e., most individuals were heterozygous for the microsatellite loci under study. The highest similarity of the spectra of microsatellite DNA fragments was revealed in laboratory stocks of house mice carrying the t ^w5 and t ^w73 haplotypes. The spectra of animals from the Rostov and Volgograd oblasts appeard to be most similar to them. The microsatellite spectra of individuals from Iran closely resemble the spectrum of an individual from Armenia. It was demonstrated that amplified microsatellite fragments localized in the region of the t-complex can be used to identify representatives of the Mus genus from wild populations.