Evolution of mammalian X-linked and autosomal Pgk and Pdh E1 alpha subunit genes

The phylogeny and substitution rates of the mammalian X chromosome- located and autosomal phosphoglycerate kinase and pyruvate dehydrogenase genes were investigated. Compatibility analysis was used to show reticulate evolution in these genes. Analysis of the marsupial, mouse, and human phosphoglycerate kinase genes suggests that at least two recombination events have taken place, one occurring about the time of the placental-marsupial split involving exons 1-5 and the other before the primate-rodent split involving exons 9-10. Similar analysis of the pyruvate dehydrogenase genes indicates a recombination event involving exons 2-3 at a time before the primate-rodent split and a gene conversion between exons 3-4 in the human somatic and testis- specific pyruvate dehydrogenase genes after the primate-rodent split. This demonstrates that genetic exchange can occur between paralogous genes at widely separated chromosomal locations. Estimation of nucleotide substitution rates in these genes confirmed a higher substitution rate in the pyruvate dehydrogenase genes. In the phosphoglycerate kinase genes, there is no difference between the substitution rates in mice and humans and between the X chromosome- and autosome-located genes. A greater substitution rate was noted in the mouse autosomal pyruvate dehydrogenase gene when compared with the other mouse and human genes. This may be a result of either directional natural selection or a relaxation of functional constraint at this specific gene.      

Phosphorylation and biosynthesis of high molecular weight proteins of tumor nuclear matrix

INTRODUCTIONAsearlyasin1948wehavefr8CtionatedisolatednucleifromnormalandtumorcellsbyextractionwithiMNaCIanddilutealkali[1].Thenuclearresiduewasthenstudiedmorethoroughly[2,3].Lateron,sillillarproteinousnuclearresidueswereisolatedbyotherworkers[46]andasstud…     

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.     

Vacuolar reticulum in oomycete hyphal tips: An additional component of the Ca2+Regulatory system?

Cultures of Achlya sp., Phytophthora cinnamomi, Saprolegnia diclina, S. ferax, and S. parasitica, treated with 6-carboxyfluorescein diacetate solution, accumulate 6-carboxyfluorescein in a reticulate system of fine tubules. The network shows longitudinal polarity within the hyphae, tubules being finest toward the hyphal tips. In more mature subapical regions the network is connected with large vacuoles that also accumulate 6-carboxyfluorescein. A morphologically similar system has also been identified in freeze-substituted hyphae of S. ferax. The network is considered to be vacuolar, but differs from the tubular vacuole system of true fungi in that tubules are less motile, more frequently branched, and do not alternate with clusters of spherical vacuoles. The appearance of the network resembles patterns of calcium-sensitive dye staining and it is suggested that the vacuolar reticulum in the tip region of oomycete hyphae may act as a Ca2+ sink. The tubular reticulum in oomycetes is very fragile and can be shown with 6-carboxyfluorescein in only those hyphal tips with a motility and organelle distribution characteristic of growing hyphae with normal morphology. Diverse abnormal hyphae show a range of other fluorochrome localizations. These include large irregular compartments filled with fluorochrome, and fluorescent cytoplasm with organelles and vacuoles standing out in negative contrast. These localizations in abnormal hyphae are correlated with other structural changes indicative of damage. Special care is required in experiments with oomycetes to avoid such artefacts of localization. Copyright 1997 Academic Press. Copyright 1997 Academic Press     

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.