Effect of amidopyrine on the rate of cytochrome P-450 isoform breakdown

The effect of liver monooxygenase system substrates upon the rate of cytochrome P-450 isoform degradation was investigated by measuring the half-life of liver microsomal proteins in C57BL/6 mice injected with phenobarbital and then 24 hours later with aminopyrine every 6 hours. The rate of phenobarbital-induced degradation of cytochrome P-450 isoform (mol weight 56000 daltons) was shown to be increased two-fold.     

Heart Rate Variability during Performance of Various Resultive Tasks

Heart rate variability was studied in 30 subjects before and after the assembling of a single-type color mosaic. The heart rate analysis was performed by evaluating its statistical structure (variation curves, scatter plots, and standard deviation). The wave structure of a series of cardiointervals was assessed by calculating and plotting the autocorrelation function. Certain heart rate parameters in different subjects reflected to various extents their success in achieving the useful end result of the visuomotor design task.     

3D Structure Model of the Principal Neutralizing Epitope of Minnesota HIV-1 Isolate

Abstract

A hierarchical procedure, using a “bottom-up” strategy and combining (i) a probabilistic approach for estimating all possible starting structures, (ii) restrained molecular mechanics algorithms for preliminary selection of all energetically preferred conformers, as well as (iii) quantum chemical computations for refining their geometry, was used to study the structural properties of the HIV-MN neutralizing epitope in terms of NMR spectroscopy data. As a result, only one of initial structures matching the experimental and theoretical data was found to be well-ground for implementing the function of immunoreactive conformation of the virus immunogenic crown. The geometric parameters of this structure in water solution were shown to correspond to a double β-turn conformation similar to that revealed in crystal for synthetic molecules imitating the central region of the HIV-MN V3 loop. The following conclusion was drawn from the comparative analysis of simulated structure with the one computed previously: the HIV-MN immunogenic tip has some inherent conformational flexibility that manifests at the alterations of hexapeptide environment and leads to the structural transitions changing the local conformation of the stretch of interest but retaining its spatial main chain fold. As a matter of record, the high resolution 3D structure model for the HIV-MN principal neutralization site was constructed, and its geometric parameters were compared with the corresponding characteristics of conformers derived earlier for describing the conformational features of immunogenic tip of gp120 from Thailand HIV-1 isolate.

The results are discussed in the light of literature data on HIV-1 neutralizing epitope structure.     

Modeling of the spatial structure of an HIV-haiti immunodominant epitope

A model of the spatial structure of the immunodominant epitope of human immunodeficiency virus type 1 (HIV-Haiti virion) consistent with the NMR data was constructed using an earlier proposed method based on theoretical calculations. It was found that, in aqueous solution, the main immunogenic region of the virus protein gp120 took the prevalent conformation of a double β-turn IV–IV. It is shown that two structures of this fragment found in the crystal were present in the set of preferable conformations of the HIV-Haiti immunodominant epitope. On the basis of comparative analysis of the 3D structures of the immunodominant epitopes of type 1 human immunodeficiency virus (HIV-Haiti, HIV-Thailand, and HIV-MN virions), it was concluded that the studied gp120 fragment forms similar spatial backbone structures in these three virus subtypes; however, these structures are formed from different local minimums of the constituent amino acids. It was assumed that the detected distinctions between the local structures of this fragment determine the specificity of HIV-1 binding to virus-neutralizing antibodies.     

Species composition and distribution of ichthyoplankton in the White Sea in July 2003

On the basis of an ichthyoplankton survey made in July 2003 in Kandalaskha Gulf, the Basin, the Gorlo Strait, and the Voronka the species composition and distribution of fish eggs and larvae are investigated. The ichtyoplankton comprises 17 fish species, of which the majority (11) were boreal forms. Other fish were represented by arctic species (2) and arctic-boreal species (4). The traits of distribution of abundantly caught species are considered in detail: larvae of the White Sea oligovertebrate herring Clupea pallasii marisabli, eggs of the dab Limanda limanda, larvae of the northern sand lance Ammodytes marinus, and of the capelin Mallotus villosus villosus. The presence of all larvae of White Sea herring only within Kandalaskha Gulf is considered to be evidence supporting the hypothesis suggested by Dmitriev (1946) on the absence of their drift beyond large gulfs of the White Sea. The natural barrier for mutual exchange with early developmental stages of fish between the White Sea and the Barents Sea in summer may be a developed hydrologic front in the boundary area of the Basin and Gorlo Strait, discovered in the course of the survey. This front causes their death by thermohaline shock in the abrupt gradient zone.     

Variability of continuous insect cell lines and their identification

Continuous insect cell lines make a special object of research in biology. Insect cells in the established lines differ in the number of attributes from both normal differentiated, and embryonic cells. The period of genome destabilization necessarily precedes cell line immortalization. Genome destabilization is manifested by changes in genome size, cell karyotype, amplification of some retrotransposone families, and induction of their expression. The existence of significant genetic variability in one line puts a problem of searching for invariant attributes providing culture identification and defining the limits of normal polymorphism of cells in the culture. Using the vast collection of insect continuous cell lines stored at the N. I. Vavilov Institute of General Genetics RAS, nine lines were identified by RFLP method of mitochondrial DNA. Variability of DNA-polymorphisms, cellular karyology, morphology, immunological and biochemical attribute in the culture is discussed.     

Studies of Nitric Oxide Production in Rat Tissues in Postnatal Development by Electron Paramagnetic Resonance Spectroscopy

Biophysics - Paramagnetic complexes containing nitric oxide (NO) have been assayed in rat heart and liver tissues by EPR spectroscopy to investigate the time variation of NO production during...