Autoantibodies to the thrombocytes and erythrocytes in HIV-infected patients

In 48 patients with HIV infection were tested for the presence of autologous and allogenic antibodies to red blood cells with the use of Coombs' direct and indirect tests. 18 HIV-infected patients had IgG antibodies to thrombocytes, circulating in the blood (detected by the method of EIA) and bound to thrombocytes (detected by the method of RIA). In 5 out of 48 patients Coombs' direct test yielded positive results with red blood cells. 6 out of 18 examined patients had an elevated content of thrombocyte-bound antibodies. The presence of cross reactions between gp120 of human immunodeficiency virus and gp3a thrombocytes led to the formation of antithrombocyte antibodies and, consequently, to a decrease in the number of thrombocytes.     

Presence of melanocortin (MC4) receptor in spiny dogfish suggests an ancient vertebrate origin of central melanocortin system.

We report the cloning, expression, pharmacological characterization and tissue distribution of a melanocortin (MC) receptor gene in a shark, the spiny dogfish (Squalus acanthias) (Sac). Phylogenetic analysis showed that this receptor is an ortholog of the MC4 subtype, sharing 71% overall amino acid identity with the human (Hsa) MC4 receptor. When expressed and characterized by radioligand binding assay for the natural MSH (melanocyte-stimulating hormone) peptides alpha-, beta-, and gamma-MSH, the SacMC4 receptor showed pharmacological properties very similar to the HsaMC4 receptor. Stimulation of SacMC4 receptor transfected cells with alpha-MSH caused a dose-dependent increase in intracellular cAMP levels. The SacMC4 receptor has Ala in position 59 where all other cloned MC receptors have Glu. We confirmed that this was not due to individual polymorphism and subsequently mutated the residue 'back' to Glu but the mutation did not affect the pharmacological properties of the receptor. SacMC4 receptor mRNA was detected by RT-PCR in the optic tectum, hypothalamus, brain stem, telencephalon and olfactory bulb but not in cerebellum or in peripheral tissues. This study describes the first characterization of an MC receptor in a cartilaginous fish, the most distant MC receptor gene cloned to date. Conservation of gene structure, pharmacological properties and tissue distribution suggests that this receptor may have similar roles in sharks as in mammals and that these were established more than 450 million years ago.     

Phylogenic and geographic analysis of chum salmon Oncorhynchus keta (Walbaum) in Asian populations based on mitochondrial DNA variation

We used restriction length polymorphism (RFLP) analysis of PCR-amplified fragments of mtDNA to study the genetic structure of chum salmon populations sampled in 1993-2000 during a spawning run in five rivers: Narva (Southern Primorye), Naiba (Sakhalin Island), Sernovodnaya (Kunashir Island, Southern Kuril Islands), Ola (northwestern coast of the Sea of Okhotsk), and Anadyr' (Chukotka Peninsula). In total, 49 haplotypes were identified in 193 fish. Heterogeneity tests showed highly significant (P = 0) differences among all sample pairs. The estimated time of independent divergence of the populations or population groups is in good agreement with the time of Pleistocene glaciations. This result suggests that it is cyclic global changes during this time period that were crucial in determining the within-species divergence in chum salmon. The types of mtDNA genetic variability and mismatch distribution between haplotypes in the populations indicate that the southern regions of the Sea of Okhotsk and Sea of Japan served as refugia for chum salmon during glaciation periods.     

One melanocortin 4 and two melanocortin 5 receptors from zebrafish show remarkable conservation in structure and pharmacology

We report the cloning, genome mapping, functional expression, pharmacology and anatomical distribution of three melanocortin (MC) receptors from zebrafish (z). Phylogenetic analysis showed with high bootstrap support that these genes represent one MC4 receptor and two MC5 receptors. Chromosomal mapping showed conserved synteny between regions containing zMC4 and human (h) MC4 receptors, whereas the two zMC5 receptor genes map on chromosome segments in which the zebrafish has several genes with two orthologues of a single mammalian gene. It is likely that the two copies of zMC5 receptors arose through a separate duplication in the teleost lineage. The zMC4, zMC5a, and zMC5b receptors share 70-71% overall amino acid identity with the respective human orthologues and over 90% in three TM regions believed to be most important for ligand binding. All three zebrafish receptors also show pharmacological properties remarkably similar to their human orthologues, with similar affinities and the same potency order, when expressed and characterized in radioligand binding assay for the natural MSH) peptides alpha-, beta-, and gamma-MSH. Stimulation of transfected mammalian cells with alpha-MSH caused a dose-dependent increase in intracellular cAMP levels for all three zebrafish receptors. All three genes were expressed in the brain, eye, ovaries and gastrointestinal tract, whereas the zMC5b receptor was also found in the heart, as determined by RT-PCR. Our studies, which represent the first characterization of MC receptors in a nonamniote species, indicate that the MC receptor subtypes arose very early in vertebrate evolution. Important pharmacological and functional properties, as well as gene structure and syntenic relationships have been highly conserved over a period of more than 400 million years implying that these receptors participate in vital physiological functions.     

Chemical-toxicological characteristic property of organochlorine pesticide transformation products formed under the effect of intensive fluxes of gamma-irradiation

The results of formation of stable products of organochlorinated pesticides (OCP) under gamma-irradiation (dose 10 kGy, dose rate 0.026, 0.14 kGy/min) are discussed in the article. The model solutions of alpha-,gamma-hexachlorocyclohexane (alpha-,gamma-HCH), p,p-dichlorodiphenyl-trichloroethane (p,p-DDT) and p,p-dichlorophenyl-dichloroethylene (DDE), with initial concentrations of 1.0-0.1 ppm, were exposed to gamma-radiation. Among the products of OCP radiolysis such compounds as DDE, 2,2-di(chlorophenyl)-1-chloroethylene, dichlorophenyl-dichloroethane and various isomers of HCH were found. It was shown that taking in account the whole data on the formed metabolites the toxicological characteristics of pesticide solutions cannot be improved by exposure to gamma-radiation.     

Luminescent indicators in various parts of wheat leaves in ontogenesis

A comparative study of slow fluorescence induction, fluorescence spectra, thermoluminescence, photosynthetic activity and chlorophyll content in ontogenesis of wheat seedlings (Triticum aestivum L, cv. Yubileinayd) grown in the laboratory conditions was carried out. It was shown that (FM-FT)/FT values of slow fluorescence induction increased with the age of leaf part, reached a maximum (for 2-week-old seedlings), and then decreased. Changes in (FM-FT)/FT positively correlated with the changes in photosynthetic activity per chlorophyll unit (delta O2/(delta t.chlorophyll)); the coefficient of correlation r = 0.84, p > 0.999. The F685/F730 ratio of the intensities of fluorescence spectrum decreased with the increase in chlorophyll content. The relative light sum SA/S(tot) of band A of thermoluminescence changed in the same direction as delta O2/(delta t-chlorophyll), the relative light sum (SC/S(tot) of band C of thermoluminescence decreased during leaf maturation. The regularities revealed in the experiments are discussed in terms of changes in the structural and functional organization of the photosynthetic apparatus known from the literature.     

Changes in induction of slow fluorescence in leaves of maple located near urban highways

The slow fluorescence induction parameter FM/FT was measured for green leaves from maple trees grown in the park, depending on the distance (5-65 m) between the tree and the highway cross. We concluded that the decrease in the value of FM/FT for trees grown in the vicinity of the road cross was caused by exhaust gases.     

BPAG1a and b Associate with EB1 and EB3 and Modulate Vesicular Transport,Golgi Apparatus Structure,and Cell Migration in C2.7 Myoblasts

BPAG1a and BPAG1b (BPAG1a/b) constitute two major isoforms encoded by the dystonin (Dst) gene and show homology with MACF1a and MACF1b. These proteins are members of the plakin family, giant multi-modular proteins able to connect the intermediate filament, microtubule and microfilament cytoskeletal networks with each other and to distinct cell membrane sites. They also serve as scaffolds for signaling proteins that modulate cytoskeletal dynamics. To gain better insights into the functions of BPAG1a/b, we further characterized their C-terminal region important for their interaction with microtubules and assessed the role of these isoforms in the cytoskeletal organization of C2.7 myoblast cells. Our results show that alternative splicing does not only occur at the 5′ end of Dst and Macf1 pre-mRNAs, as previously reported, but also at their 3′ end, resulting in expression of additional four mRNA variants of BPAG1 and MACF1. These isoform-specific C-tails were able to bundle microtubules and bound to both EB1 and EB3, two microtubule plus end proteins. In the C2.7 cell line, knockdown of BPAG1a/b had no major effect on the organization of the microtubule and microfilament networks, but negatively affected endocytosis and maintenance of the Golgi apparatus structure, which became dispersed. Finally, knockdown of BPAG1a/b caused a specific decrease in the directness of cell migration, but did not impair initial cell adhesion. These data provide novel insights into the complexity of alternative splicing of Dst pre-mRNAs and into the role of BPAG1a/b in vesicular transport, Golgi apparatus structure as well as in migration in C2.7 myoblasts.