[Evolutionary changes in amino acid composition of dicotyledonous seeds]. / Izmenenie v aminokislotnom sostave semian dvudol'nykh rastenii v protsesse évoliutsii.

Amino acid composition of dicotyledonous seeds of 82 genera, 67 families, 48 orders, and 8 subclasses (after Takhtadzhyan, 1987). Within the frames of hypothesis of amino acid composition of the least specialized hypothetical taxon we have established a universal trend for all dicotyledonous classes--increased proportion of glutamic acid and arginine. Divergent processes are pronounced in the evolution of amino acid composition within the families and orders. Pairwise comparison of amino acid composition in all analyzed taxons demonstrated high similarity between taxons from different subclasses and at different levels of biochemical specialization. Within the frames of the system proposed by Takhtadzhyan (1987) we interpret this as a clearly pronounced parallel variability of the seed amino acid composition realized during evolution of taxons in various dicotyledonous orders and subclasses.

[Adaptive types of prolamins--specialized proteins from cereal seeds (Poaceae Banrh.)]. / Adaptivnye tipy prolaminov, spetsializirovannykh belkov semian zlakov (Poaceae Barnh.).

Amino acid composition of prolamins and the whole seed in representatives of 52 cereal genera and 22 tribes, as well as amino acid composition of seed protein fractions in representatives of 9 cereal genera are presented. In terms of proposed directed evolution of the seed proteins and adaptive role of prolamins in evolution and distribution of cereals, generalized data on their content in seed protein complex, electrophoretic, immunochemical, and amino acid composition of the seeds, we develop the notion of prolamins biochemical specialization and their polyphyletic origin during evolution of cereal seed protein complex. Seven adaptive types of prolamins are recognized: Sasa, Molinia, Chloris, Zingeria, Poa, Triticum, and Panicum types. Adaptive types of prolamins were formed in response to an ecological request of the environment where taxon ancestors existed and a taxon appeared and in relation to phylogenetic history of a taxon and its assignment to particular tribe and subfamily.

[Structural and functional analysis of the human immunodeficiency glycoprotein gp120 with homologous synthetic peptides]. / Strukturno-funktsional'nyi analiz glikoproteina gp120 virusa immunodefitsita cheloveka s pomoshch'iu sinteticheskikh peptidov, gomologichnykh ego strukture.

The purpose of the study was to identify sites of gp 120, which are responsible for CD4 binding and induce tumor necrosis factor-alpha (TNF-alpha) synthesis. Seven peptides were synthesized from gp 120. The peptides were studied in the following biological tests: binding to CD4 molecules of the Jurkat cell clones 3G6 and PBMC of healthy persons. There was TNF-alpha induction in healthy and HIV-positive individuals and its correlation was found with p24 antigenemia in HIV patients. The peptides 420-440, 426-452, 369-384, 255-272 bind to T-lymphocytic CD4 and induced TNF-alpha. The peptide 436-451 binds to CD4, but failed to induced TNF-alpha, which suggests that the latter may be used as a basis for HIV-infection vaccine.

The sequence 130-137 of human interferon-alpha 2 is involved in the competition of interferon, prothymosin alpha and cholera toxin B subunit for common receptors on human fibroblasts.

125I-labelled recombinant human interferon alpha 2 (rHuIFN-alpha 2) capable of high-affinity binding (Kd = 2.46 +/- 0.18 x 10(-10) M) with receptors expressed on mouse thymocytes was obtained. Prothymosin alpha (proTM-alpha) but not cholera toxin was found to compete with radiolabelled IFN-alpha 2 for binding to the same receptor (Ki = 3.68 +/- 0.21 x 10(-11) M). The synthetic peptide covering the sequence 130-137 of IFN-alpha 2 (authors' definition: alpha-peptoferon) was shown to have the capacity to displace the labelled IFN-alpha 2 from the IFN-alpha 2/receptor complex (Ki = 7.19 +/- 0.12 x 10(-11) M). It was shown that receptors of this type are localized in plasmatic membrane fraction. Using [125I]-alpha-peptoferon, specific and saturable binding was detected on human fibroblasts and the data fitted a single binding site. Scatchard analysis yielded a Kd of 9.63 +/- 0.17 x 10(-8) M. The binding was competitively inhibited by IFN-alpha 2 (the Ki value in competition assays was 1.37 +/- 0.12 x 10(-8) M), proTM-alpha(Ki = 2.2 +/- 0.2 x 10(-7) M) and cholera toxin B subunit (Ki = 5.5 +/- 0.2 x 10(-7)). The present study has demonstrated that the sequence 130-137 of HuIFN-alpha 2 is involved in the competition of HuIFN-alpha 2, proTM-alpha and cholera toxin B subunit for common receptors on human fibroblasts.

The octapeptide corresponding to the region of the highest homology between alpha-interferon and thymosin-alpha 1 effectively competes with both cytokines for common high-affinity receptors on murine thymocytes.

The octapeptide corresponding to human interferon-alpha 2 (Hu IFN-alpha 2) sequence 131-138 has high affinity to murine thymocyte receptors (Kd = 4.2 x 10(-12) M, about 700 receptors per cell). The peptide receptor binding is inhibited by both Hu rIFN-alpha 2 (Ki = 8.6 x 10(-10) M) and thymosin-alpha 1 (TM-alpha 1) (Ki = 3 x 10(-7) M) as well as by the octapeptide homologous to the TM-alpha 1 sequence 16-23 (Ki = 4.5 x 10(-7) M). The peptide from IFN-alpha 2 (131-138) activates murine thymocyte blast transformation at a concentration of 10(-11) M in the presence of 2.5 micrograms/ml of concanavalin A.