Modifications of potassium currents at the nerve growth factor-induced differentiation of pheochromocytoma cells

Potassium currents were studied in non-differentiated and neuron type-differentiated (induction by nerve growth factor) cells of P12 pheochromocytoma. In the differentiated cells, an increase in the density of non-inactivating potassium current was observed. Fast and slow inactivating potassium currents underwent no changes.     

Properties of a spherical stratified gas discharge

Experimental data are obtained on the conditions for the stratification of spherical direct-current discharges and on the properties of the strata. The experiments were aimed at studying discharges in both molecular and inert gases at low pressures and were carried out with a steel chamber whose wall served as a cathode. An anode was placed at the center of the chamber. The discharge stratification was observed to be especially pronounced in media containing a small admixture of the vapor of a high-molecular substance (e.g., acetone). In discharges in pure inert gases, no strata were observed. The current-voltage characteristics of discharges at different pressures were obtained. The discharges were found to be unsteady: current pulses with a duration of about 1 microsecond and a characteristic repetition rate of about 1 kHz were detected against a steady current background and were found to correlate with the pulses of the integral emission from the discharge. The radius of each of the strata was determined as a function of its number and of the gas pressure and discharge current. The radial profiles of the time-averaged floating potential were measured in experiments with stratified discharges and with uniform discharges in argon.     

Nucleotide sequence variation of the mitochondrial COI gene in several eelpout species of the genus Zoarces (Zoarcidae, Pisces)

The mitochondrial COI gene was for the first time sequenced in eelpout species of the genus Zoarces from the Taui Bay of the Sea of Okhotsk: notched-fin Z. elongatus Kner, 1868 and the new sympatric form Zoarces sp., differing in a large set of morphological traits. The two species were compared with European eelpout Z. viviparus Linnaeus, 1758 from the Finnish Bay of the Baltic Sea. Divergence and phylogenetic analyses demonstrated a greater genetic similarity between Zoarces sp. and Z. viviparous than between sympatric Zoarces sp. and Z. elongatus.     

Detection of Legionella pneumophila antibodies in the blood serum of pneumonia patients by an immunoenzyme method

The conditions of making the enzyme immunoassay (EIA) for the detection of antibodies to L. pneumophila have been optimized. The use of L. pneumophila purified serotypic antigen at a concentration of 0.25 micrograms/ml for the sensitization of polystyrene plates has been shown to increase the sensitivity and specificity of the assay. 220 patients with severe pneumonia have been examined. As revealed in this investigation, antibodies to L. pneumophila can be detected in 12.2% of cases. A high degree of correlation (94.4%) between the results of EIA and the indirect immunofluorescence test has been shown.     

Relationships and position of the taxa of the subfamily Xiphisterinae in the system of the suborder Zoarcoidei (Perciformes)

Analysis of the nucleotide sequences of mitochondrial and nuclear DNA genes was used to examine the relationships and position of the subfamily Xiphisterinae in the system of the suborder Zoarcoidei. This study showed the genetic heterogeneity of Xiphisterinae and the propriety of its division into two subfamilies: Xiphisterinae with the genera Xiphister and Phytichthys and Cebidichthyinae with the genera Cebidichthys, Dictyosoma, Esselenichthys, and Nivchia. The genetic differences between the two subfamilies were not less, but in some cases even greater than the differences between families within the suborder; therefore, they should be raised to the rank of a family, Xiphisteridae and Cebidichthyidae, and classified not within the superfamily Stichaeoidae but rather as independent taxa of the suborder Zoarcoidei.     

Protein complex Ppz1p/Hal3p and the efficiency of nonsense suppression in yeasts <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

It is known that the efficiency of nonsense suppression in yeasts is controlled both genetically and epigenetically. Since many components of translation machinery are represented by phosphoproteins, the efficiency depends, in particular, on the activity of kinases and phosphatases that include the Ppz1p/Hal3p complex. It contains Ppz1p phosphatase, which is a catalytic subunit, and Hal3p that negatively regulates its function. The aim of this work was to study the mechanisms which relate the activity of Ppz1p/Hal3p complex to nonsense suppression efficiency. In this study, we used a genetic approach implicating the analysis of nonsense suppression phenotype of the strains overexpressing HAL3 or PPZ1 genes and also bearing deletions or mutant alleles of genes, which presumably could participate in the manifestation of these overexpressions. We have shown that Hal3p inhibits not only Ppz1p but also the homologous phosphatase Ppz2p. Our data indicate that Ppz2p is also involved in the control of nonsense suppression efficiency. In the course of search for Ppz1p target protein, it was shown that Ppz1p dephosphorylates at least two proteins involved in translation. Moreover, Ppz1p affects the efficiency of nonsense suppression not only due to its phosphatase activity but also due to another mechanism triggered by its interaction with Hsp70 chaperones.     

Conformational analysis of 5-substituted uracil

The high-resolution IR-spectra of 5-nitrouracil and 5-bromouracil isolated in Ar matrices at 11 K were obtained for the first time. The conformational structure of uracil 5-substituents--thymine, 5-bromouracil, 5-nitrouracil--is calculated by the molecular mechanics and quantum--chemical MINDO/3 methods. The possibility of thymine transition to nonplanar conformations is observed.     

Effect of sizes of the retinal receptive field on the precision of image perception

A paradox of sharp vision regardless of relatively large receptive fields of the retina is discussed. Transformation of images by the receptive fields or intersecting fields of vision of omma-tidia of the complex eye is described as an approximation of Bool functions by the implicant forms. Such an approximation results in the information compression. The compression coefficient is determined by the ratio between the implicants number and the number of points in the field of determination of the Bool function. The approximation errors strongly depend on the size of the receptive fields. With their increase the error abruptly decreases and only after passing the deep minimum it begins to slowly increase. The mechanism of information compression is a universal one and is similarly realized on the retina, facet and t.v. sets.