Genetic divergence of sympatric charrs of the genus Salvelinus from Nachikinskoe Lake (Kamchatka)

We studied genetic differentiation of two charr species, Dolly Varden Salvelinus malma malma Walbaum and resident lacustrine charr Salvelinus sp., which sympatrically inhabit Nachikinskoe Lake (the Bol'shaya River basin) in southwestern Kamchatka Peninsula. Using restriction analysis (RFLP), three mitochondrial DNA fragments (ND1/ND2, ND5/ND6, and Cytb/D loop) amplified in polymerase chain reaction (PCR) were compared. The divergence of the mtDNA sequences between Salvelinus sp. and S. malma malma was 2.8%; Salvelinus sp. and S. taranetzi, 0.36%; Salvelinus sp. and S. krogiusae, 0.21%; Salvelinus sp. and S. alpinus, 3.0%. These results point to reproductive isolation of charrs in Nachikinskoe Lake and support the earlier suggestion on a close relationship between Salvelinus sp., S. taranetzi, and S. krogiusae.     

Effect of weak and ultraweak static magnetic fields on the intensity of fission of the planarian Dugesia tigrina

It has been shown that, in the range of 03000 nT, a biological system differently responds to the treatment with a weak static magnetic field. Thus, at a practically complete compensation of the field (induction 5 nT), the intensity of fission of planarian does not differ from control values. As the field intensity is successively increased to 300 nT, a marked and statistically significant stimulating effect is observed (SC 1.51.8), which disappears in the intensity range of 400 and 600 nT. At intensities from 800 to 1500 nT, the stimulating effect manifests itself again. Further increase of field intensity to 3000 nT leads to the disappearance of the effect.     

Crystal structures of mutant ribosomal proteins L1

Nine mutant forms of ribosomal proteins L1 from the bacterium Thermus thermophilus and the archaeon Methanococcus jannaschii were obtained. Their crystal structures were determined and analyzed. Earlier determined structure of S179C TthL1 was also thoroughly analyzed. Five from ten mutant proteins reveal essential changes of spatial structure caused by surface point mutation. It proves that for correct studies of biological processes by site-directed mutagenesis it is necessary to determine or at least to model spatial structures of mutant proteins. Detailed comparison of mutant L1 structures with that of corresponding wild type proteins reveals that side chain of a mutated amino acid residue tries to locate like the side chain of the original residue in the wild type protein. This observation helps to model the mutant structures.     

Differences in activation of the motoneurone inhibitory receptors in a frog Rana ridibunda by GABA and glycine and their interaction

The membrane potential responses evoked by GABA and glycine bath applications were studied intracellularly in the motoneurons of the isolated frog spinal cord. The amplitude of glycine-evoked responses was 1.5-2.0 larger than that of GABA-evoked response at the same concentration. EC50 were 0.75 mM and 1.57 mM for glycine and GABA, respectively. The amplitude of responses induced by the simultaneous applications of both agonists were 79.1 +/- 2.4% (n = 19) of the sum of individual responses and 130.1 +/- 1.5% (n = 19) of individual glycine-induced responses (partial occlusion). GABA-evoked responses were decreased by 85.3 +/- 0.2% (n = 10) as a result of glycine preliminary application while preapplication of GABA reduced glycine-evoked responses only by 52.9 +/- 0.3% (n = 11). Glycine- and GABA-evoked responses were selectively suppressed by strychnine and bicuculline, respectively. These results suggest that amphibian spinal motoneurones express (less specifically than those of mammals) both glycine (predominantly) and GABAA receptors, with asymmetric cross-inhibition possibly taking place in them.     

Substituted 16alpha,17alpha-cyclohexanopregnanes: the anionic oxy-Cope rearrangement of 3beta-tert-butyldimethylsilyloxy-19-hydroxy-19-vinyl-16alpha,17alpha-cyclohexapregn-5-en-20-one

(19R)- and (19S)-tert-Butyldimethylsilyl (TBS) ethers of 19-hydroxy-19-vinyl-16alpha,17alpha-cyclohexanopregn-5-en-20-ones were synthesized. These compounds containing the 1,5-oxydienoic motif were subjected to the anionic oxy-Cope rearrangement to obtain 3beta-TBS ether of 6beta-(3-oxopropyl)-16alpha,17alpha-cyclohexano-19-nor-pregn-5(10)-en-20-one. The structures of the compounds synthesized were confirmed by the analysis of their H and 13C NMR spectra.     

EDAS, databases of alternatively spliced human genes

EDAS, a database of alternatively spliced human genes, contains data on the alignment of proteins, mRNAs, and EST. It contains information on all exons and introns observed, as well as elementary alternatives formed from them. The database makes it possible to filter the output data by changing the cut-off threshold by the significance level. The database is accessible at http://www.gene-bee.msu.ru/edas/.     

The experience of FISH technique application for reconstruction of individual radiation doses in Chernobyl liquidators in the framework of Ukrainian-American project "Leukemia"

The results of proper investigations received under the cytogenetic examination of 225 persons (control groups, Chernobyl liquidators exposed to different radiation doses, oncogematology patients) had been summarized and analyzed. The conclusion concerning possibilities and limitations of FISH technique usage for retrospective biodosimetry of human radiation exposure has been presented.     

Activity of the corn Spm transposon system in transgenic plants Orychophragmus violaceus (L.) O.E. Schulz obtained by both direct transfer of DNA to protoplasts and agrobacterial transformation of root explants

Transposon mediated insertional mutagenesis is one of the approaches for the unique gene cloning. A wild species of Cruciferae family Orychophragmus violaceus (L.) O.E. Schulz, which is of interest for practical breeding as a donor of improved plant oil, was an object of the investigation. Plasmid construction used in the experiments included selective NPT II gene, reported GUS gene serving as an excision marker, structural BAR gene located within the dSpm element and Spm transposase. The GUS gene of this plasmid had not his own promoter and became functional only after Spm-transposition. Transformed Orychophragmus violaceus (L.) O.E. Schulz. plants were obtained by direct mesophyll protoplast transformation as well as Agrobacterium tumefaciens-mediated root explant transformation. Gene transfer and the transposition event were confirmed by the GUS activity and the PCR analysis. Relative transformation efficiency using protoplasts was 5.8%.     

Results of point stenting of extended coronary stenosis in patients with ischemic heart disease

The paper analyzes the immediate and long-term results of point stenting in patients with extended (more than 30 mm) coronary stenoses and compares them with those obtained by routine stenting. The study included 177 patients with varying extent stenoses who underwent traditional implantation of intracoronary stents. Thirty-seven patients undergone the so-called point stenting formed a separate group. There was no significant difference in clinical and angiographic success rates between the patients of all three groups. Significant difference was also absent in subacute stent thrombosis between the patients of Groups 2 and 3 and those of the point stenting group. Thus, acute or subacute stent thrombosis was noted in 4 (2.3%) patients from the routine stenting groups, all the patients being from Groups 2 and 3, and in 2 (5.4%) from the point stenting group. No significant difference was found in the incidence of recurrent angina pectoris (restenosis) between Groups 1 and 2 and between Groups 2 and 3. At the same time, recurrent angina (restenosis) significantly more frequently developed in the patients of Group 3 than those of Group 1. As compared with Groups 2 and 3 patients, there was no significant difference in the incidence of recurrent angina (restenosis).     

Divalent cations and nifedipine action on Ca(2+) transport into myometrial plasmalemma vesicles

While using 45Ca2+ on the model of "outside-out configuration" vesicules of the myometrium cells sarcolemma an investigation of Cd2+, Zn2+, Co2+ and niphedipin on Ca2+ transport into the vesicules in the conditions of protons gradient transmembrane dissipation has been conducted. The above listed substances blocking effect corresponds to their physicochemical properties. Cadmium and zinc ions are considerably more effective in suppressing Ca2+ transport into the vesicules under the dissipation of delta pH on the membrane if compare with the case of delta pH = 0. In the case of niphedipin inhibiting action an opposite result is observed. The hypothesis has been made, that dissipation of delta pH on the sarcolemma is capable to strengthen the transmembrane Ca2+ transport by means of changing the channel structures conformation.