Episodes of adaptive evolution of mitochondrial genome in asiatic salamanders (Amphibia,Caudata, Hynobiidae)

To elucidate the effect of natural selection on the evolution of mitochondrial DNA (mtDNA) in Asiatic salamanders of the family Hynobiidae, nucleotide sequences of 12 protein-coding genes were analyzed. Using a mixed effects model of evolution, it was found that, in spite of the pronounced effect of negative selection on the mtDNA evolution in Hynobiidae (which is typical for the animals in general), two phylogenetic clusters, the West Asian one, represented by the genera Ranodon and Paradactylodon, and North Eurasian one, represented by the genus Salamandrella, were formed under the influence of episodic positive selection. Analysis of protein sequences encoded by the mitochondrial genome also supported the influence of positive selection on the evolution of Hynobiidae at some stages of their cladogenesis. It is suggested that the signatures of adaptive evolution detected in the mtDNA of Hynobiidae were determined by the complex and long-lasting history of their formation, accompanied by adaptation to the changing environment.     

The determination of lipopolysaccharide admixtures in protein preparations

A new method for the determination of lipopolysaccharide (LPS) admixtures in protein solutions has been developed. The method includes the periodate oxidation of LPS, biotinylation with biotin hydraside, immobilization on a nitrocellulose membrane and the development of biotinylated LPS in the streptavidin--alkaline phosphatase system. Proteins are previously removed from the solution by treatment with hot phenol. Development with the use of 5-bromoinodyl phosphate and nitrotetrazolium blue makes it possible to detect about 30 pg of LPS immobilized on the nitrocellulose membrane.     

Role of magnetic resonance imaging in the complex radiation diagnosis of hormonally active adrenal tumors

Based on the results of examination of 30 patients with hormonally active adrenal tumors, the authors consider the MRI sympatomatology of their different types and the potentialities of the technique in the complex radiation diagnosis of this pathology. The authors present their assessments of the relative intensity of a signal and the structure of each type of hormone-producing tumors of the glands by using different MRI pulse sequences that may be useful in establishing a presumptive morphological diagnosis. They identify MRI sequences that are of the greatest informative value for the diagnosis of each type of hormonally active adrenal tumors. There is evidence for that MRI is highly effective in detecting all types of hormonally active adrenal tumors and, in the context of their topographic and anatomic diagnosis, has an unquestionable advantage over ultrasonography and X-ray computed tomography in some cases.     

Analysis of immune response of guinea pigs infected with Brucella melitensis

The dynamics of the first antigen specific stage of immune response to Brucella infection was experimentally studied with the method of binding adsorbed antigenic immunoreagents with lymphocytes. The study revealed that the content of antigen-binding lymphocytes (ABL) reached its maximum as early as on day 7 after infection, gradually decreasing afterwards (but even on day 90 ABL could be detected in the blood). The specificity of ABL was proved by the fact that they were absent in noninfected animals, while in the animals infected with Brucella their content was higher than that of ABL specific to Yersinia enterocolitica O9; Brucella-specific ABL bound Brucella lipopolysaccharide (LPS) more intensively than Yersinia LPS. The detection of Brucella-specific ABL was inhibited by Brucella LPS more actively than by Yersinia LPS. The evaluation of the affinity of ABL to homologous LPS, made by the ratio of binding immunoreagents of the same specificity, but with suboptimal and optimal specificity, proved that an increase in the avidity of ABL occurred in the dynamics of the infectious process, which corresponded to the increase of their specificity.     

The Structure of the Gene Pools of the Ethnic Populations of Altai–Sayan Region Based on of Mitochondrial DNA Polymorphism Data

Using the data on mitochondrial DNA (mtDNA) polymorphism, genetic structures of the four Turkic-speaking ethnic groups of Altai–Sayan highlands, Southern Altaians (Altai- Kizhi), Khakassians, Shorians, and Sojots, were described. Mitochondrial gene pools of the populations examined were characterized by different ratios between Mongoloid (M*, C, D, E, G, A, B, and F) and Caucasoid (H, U, T, J, and K) mtDNA lineages. All the populations studied had a strongly pronounced Mongoloid component, the frequency of which was 88.2% in Sojots, 75.9% in Khakassians, 67.4% in Altaians, and 64.3% in Shorians. Maximum frequency of the Caucasoid component (35.7%) was observed in Shorians. Phylogenetic and statistical analyses of the mtDNA group frequency distribution patterns in the gene pools of the ethnic populations of Altai–Sayan highlands and the adjacent territories showed that the populations of the region fell into three groups. The first group included Khakassians, Tuvinians and Altaians, the second group consisted of Sojots, Buryats, and Mongols, while the third group was composed of Uigurs, Kazakhs, and Kyrgyzes. The isolated position of Shorians among the populations examined can be explained by their different anthropological composition and their presumptive relatedness to Finno-Ugric populations of Siberia.     

Enhancement of human immunodeficiency virus type 1 envelope-mediated fusion by a CD4-gp120 complex-specific monoclonal antibody.

The entry of human immunodeficiency virus type 1 (HIV-1) into cells is initiated by binding of the viral glycoprotein gp120-gp41 to its cellular receptor CD4. The gp120-CD4 complex formed at the cell surface undergoes conformational changes that may allow its association with an additional membrane component(s) and the eventual formation of the fusion complex. These conformational rearrangements are accompanied by immunological changes manifested by altered reactivity with monoclonal antibodies specific for the individual components and presentation of new epitopes unique to the postbinding complex. In order to analyze the structure and function of the gp120-CD4 complex, monoclonal antibodies were generated from splenocytes of BALB/c mice immunized with soluble CD4-gp120 (IIIB) molecules (J. M. Gershoni, G. Denisova, D. Raviv, N. I. Smorodinsky, and D. Buyaner, FASEB J. 7:1185-1187 1993). One of those monoclonal antibodies, CG10, was found to be strictly complex specific. Here we demonstrate that this monoclonal antibody can significantly enhance the fusion of CD4+ cells with effector cells expressing multiple HIV-1 envelopes. Both T-cell-line-tropic and macrophage-tropic envelope-mediated cell fusion were enhanced, albeit at different optimal doses. Furthermore, infection of HeLa CD4+ (MAGI) cells by HIV-1 LAI, ELI1, and ELI2 strains was increased two- to fourfold in the presence of CG10 monoclonal antibodies, suggesting an effect on viral entry. These findings indicate the existence of a novel, conserved CD4-gp120 intermediate structure that plays an important role in HIV-1 cell fusion.     

Biological characterization of Bifidobacterium and Lactobacillus preparations made with the use of hydrolysate-milk and hydrolysate-soybean media]

A complex of biological characteristics important for design of the therapeutic and prophylactic activities of Bifidobacterium and Lactobacillus preparations made with the use of hydrolysate-milk and hydrolysate-soybean media was comparatively estimated. The use of the hydrolysate-soybean medium resulted in an increase of the antagonistic activity of the preparations against a number of opportunistic pathogens that was not connected with changing of their acidity and the content of lysozyme, a bacteriolytic enzyme in the culture fluid. The change in the cultivation conditions due to substitution of the hydrolysate-milk medium for the hydrolysate-soybean medium stimulated the adhesive capacity of the production strains used in the study, which was especially evident with respect to the representatives of the genus Bifidobacterium.     

Fatty acid composition of phospholipids of myelin and synaptosomal proteolipid complexes from vertebrate brain.

1. Fatty acid composition of five main phospholipids of vertebrate brain myelin and synaptosomal proteolipids and membranes was studied. 2. Higher content of monoenoic and lower content of saturated and polyenoic fatty acids was found to be characteristic of phospholipids from myelin and myelin proteolipids as compared to phospholipids from synaptosomal proteolipids and membranes of vertebrates (from fishes to mammalians). Fatty acid composition of phospholipids of proteolipid complexes and of the membranes, from which they were isolated, were found to be similar in various species studied. 3. Microviscosity was found to be higher in myelin as compared to synaptosomal membranes of frog Rana temporaria and in rabbit Lepus cuniculus. It appears to be due to the difference in proteolipid content and in lipid composition of myelin and synaptosomal membranes.