Transmission of parasites in the coastal waters of the Arctic seas and possible effect of climate change

The review deals with the biodiversity, life cycles, distribution and temperature adaptations of parasites circulating in the coastal waters of northern polar seas. Special attention is given to helminths of marine birds, which are the most common parasites in the coastal waters. Among them, the focus is on trematodes. Factors responsible for the impoverished species composition of parasites in the Arctic are analyzed. It is shown that species without free-living larvae in the life cycle have an advantage in this environment. The abundance of cestodes and acanthocephalans in Arctic seabirds is linked with the high proportion of crustaceans in their diet. The phenomenon of nonspecific parasitism (occurrence of parasites in atypical host species) is analyzed from an evolutionary viewpoint. Characteristic features in the spatial distribution of infection of marine coastal invertebrates with parasite larvae are considered, and factors that determine it are specified. The prevalence of infection in intermediate hosts is closely connected with the abundance of final hosts, which makes it possible to estimate the abundance of final hosts in a given region and reveal trends in its changes. Trematodes have a high potential for temperature acclimation. This facilitates their transmission in the northern seas but, on the other hand, makes it unlikely that the transmission process would be intensified upon an increase in summer temperatures resulting from climate warming. However, intensification of transmission may well occur due to the prolongation of the warm season (“transmission window”), which has been predicted and is already observed. It is suggested that warming in the Arctic promotes both the entry of certain “southern” species into the Arctic and the trans-Arctic interpenetration of the North Atlantic and North Pacific parasitic faunas. A case is made for the necessity to broaden the scope of parasitological research in the Arctic and Subarctic, including parasitological monitoring at the reference sites of the sea coast.     

Factor analysis of rat behavior in the open-field test

Method of major components, a variety of factor analysis, was used for evaluation of rats behaviour motivational structure in the open field test. 40 outbred rats of Wistar line (20 males and females) were examined in which 22 behaviour characteristics were studied. It was shown that a greater part (60%) of rats individual behaviour variability in the open field test was determined by the action of three major components (factors), which were defined as "investigation", "fear" and "shifted activity". Factor structure was studied of main characteristics of behaviour, recorded in the open field test. The use of factor analysis allowed to carry out animals classification on the basis of their disposition in coordinates of the obtained major components.     

The dependence of the functional activity of "immune" macrophages on T-cells

The dependence of the functional activity of the peritoneal macrophages of mice immunized with Francisella tularensis vaccine strain on the presence of T-cells in the culture has been studied. The elimination of "immune" macrophages and sensitized T-lymphocytes by means of anti-Thy-1-2-serum has been shown to lead to a sharp decrease in both ingestive and digestive functions of the phagocytic mononuclears of peritoneal exudate to the level of the activity of macrophages isolated from intact animals.     

Calculation of stable conformations of the molecule of a serum thymic factor

Stable conformations of "facteur thimique sérique" (FTS) were determined by semi-empirical conformational analysis. The interpretation of the calculation results in combination with data on biological activity of the conformationally restricted FTS analogues enabled the delineation of a possible "biologically active" conformation.     

Genetic structure of an isolated group of the indigenous population of northern Siberia--Nganasans (Tavgiitsi) of Taymyr. I. History, erythrocyte and serum blood systems, isoenzymes]

Nganasans is a small samodyen-speaking ethnic group originated from several clans of reindeer hunters. Pedigree studies revealed no consanguineous matings of uncle-niece, aunt-nephew, first cousins type among 120 families studied. Rather rarely mating between second cousins could be observed. The reviewed traditional kindship system based on bilateral exogamy is an explanation. Data on 12 blood systems and 6 red cell enzymes distribution in two main localities almost totally studied have been presented. No A2, r, K, MS alleles were observed. Hgh frequencies of Ns, R2, Fya, Jka, Gm1 have been found. Diegoa was seen in only one family. Polymorphism on PGM1, 6-PGD, AK and AP, monomorphism on LDH and MDH has been observed.     

Evolutionary Development of the Immunoglobulin Family

The origin of the ability of immunoglobulins (Ig) and T-cell receptors (TCRs) to specifically recognize antigens is related to the evolutionary development of proteins of the immunoglobulin superfamily (IgSF). The IgSF proteins are characterized by specific domain organization of molecules and statistically significant homology with known Ig. Four types of Ig domains (V1, V2, C1, and C2), differing from one another both in variations of their spatial organization and in the number of amino acid residues have been distinguished. Immunoglobulin superfamily comprises Ig; TCRs; class I and II major histocompatibility complex (MHC) molecules; one-domain proteins of thymocytes and T-cells (Thy-1); myelin protein P₀; ₂-microglobulin; two-domain proteins, such as sponge receptor tyrosine kinase (RTK), sponge adhesive protein (SAP), Drosophila tyrosine-kinase receptor (DTCR), Xenopus and human cortical-thymocyte receptors (CTX and CTH), etc.; and a large group of adhesins, coreceptors, and Ig receptors with varying number of domains. Evolutionary development of IgSF began with the evolvement of chaperones, Thy-1, and P₀ of prokaryotes and unicellular eukaryotes. Mutations, duplications, and translocations of the genes controlling both V and C domains yielded proteins with different numbers and combinations of these domains. All IgSF proteins are divided into two groups. The first group includes the proteins with nonrearranging V2 domains and homophilic mode of interaction; the second, the proteins with rearranging V1 domains and heterophilic mode of interaction (Ig, TCRs). The ability for heterophilic antigen-binding mode of interaction was apparently acquired due to the introduction of recombination-activating retroviral genes (RAG1 and RAG2) into the genome of Gnathostomata ancestors.     

3D Modeling for TM Receptors: Algorithms and Validations

This paper outlines the basic strategy to build 3D models of transmembrane G-protein coupled receptors (GPCRs) starting from their amino acid sequences in a block-by-block manner: (i) locate possible TM helical fragments in the GPCR sequence; (ii) build 3D structures for these helices; (iii) arrange isolated helices across the membrane; (iv) calculate all pairwise helix-helix interactions; (v) assemble helical bundle(s); (vi) restore interhelical loops and N- and C-termini; and (vii) refine the entire 3D structure(s). Computer algorithms and preliminary results for most of the steps are discussed.     

Dermatoglyphics of the nganasans and the forest entsy from the Taimir Peninsula

Dermatoglyphic data on 17 traits (digital arches, ulnar loops, whorls, patterns on the hypothenar and thenar/I,II,III, and IV interdigital areas, main line C absence and its incompleteness, mean digital ridge-count, a–b, b–c, and c–d ridge–counts, atd angle, pattern intensity index, and main line index) are presented in this paper for 194 males and 224 females from the Taimir Peninsula. Also presented is a population analysis of the Taimir aborigines based on quantitative traits, and comparisons of this population with some Siberian and North American populations.