[Classification of self-organizing peptides].

Amino acid sequences of known natural and synthetic self-assembling peptides were searched and analyzed for their characteristic patterns. The attempted formal numerical description of the repeating motifs, which have been revealed, resulted in building of general classification system embracing core-sequences of the peptides capable of nanostructure formation. Advantages and potency of the proposed rational classification were demonstrated via its comparison with the output from the earlier system described by the others.

Azoxymethane-induced fulminant hepatic failure in C57BL/6J mice: characterization of a new animal model.

Without transplantation, approximately 50-90% of all patients with fulminant hepatic failure (FHF) die. This poor outcome is due in part to the absence of an appropriate animal model, which would allow for a greater understanding of the pathophysiology of this syndrome. Given the reports of liver injury in humans and livestock fed cycad palm nuts on the island of Guam, we hypothesized that the active ingredient azoxymethane (AOM) could cause FHF. We therefore evaluated AOM in C57BL/6J mice. Histologically, we observed microvesicular steatosis 2 h, sinusoidal dilatation 4 h, and centrilobular necrosis 20 h after AOM administration, and transmission electron microscopy showed that this agent causes mitochondrial injury. FHF was associated with all four stages of encephalopathy, as well as by a prodromal period of decreased eating and drinking lasting approximately 15 h before the development of stage I encephalopathy (i.e., loss of scatter reflex). Late encephalopathy was associated with increased arterial ammonia, decreased serum glucose, and evidence of brain edema (astrocyte swelling). We show that AOM-induced FHF is highly reproducible, without evidence of lot-to-lot variability, and is dose dependent. These findings therefore suggest that AOM is an excellent agent for the study of FHF, as well as indicate that Guamanian FHF may be due to AOM found in unwashed cycad palm nuts.

[Interaction of cytokines with cellular receptors]. / Vzaimodeistvie tsitokinov s kletochnymi retseptorami.

The cytokinin family includes biologically active polypeptide molecules secreted by haemopoietic and immunocompetent cells which control cell proliferation and differentiation. Cytokinin interactions with specific receptors of the cell surface results in oligomerization of these receptors, i.e. in association of two or more membrane molecules. It is becoming obvious that oligomerization of receptors is an indispensable stage in the manifestation by cytokinins of their biological activity. In this context, studies of regularities of cytokinin receptor interactions resulting in receptor oligomerization is important for both elucidation of molecular mechanisms underlying kinin action and construction of compounds having the properties of agonists (or antagonists) of cytokinin-induced oligomerization of membrane receptors. A conclusion is draw about the important role of polyvalent cytokinin interactions with cell receptors in the initiation of oligomerization and subsequent formation of functionally active receptor complex.

Early lymphocyte activation events are inhibited by antiproliferative synthetic peptide 2438, a fragment of human interferon alpha-2, and immunosuppressant cyclosporine A.

A synthetic peptide (designated 2438) corresponding to the human interferon alpha-2 amino acid sequence 124-138 inhibits proliferation of T-lymphocytes in vitro. Time-course experiments suggest that peptide 2438 affects early stages of lymphocyte activation. Molecular mechanisms of peptide 2438 action were studied. By western-blotting with monoclonal antibodies against phosphotyrosine peptide 2438 was shown to decrease the phosphotyrosine content of an endogenous protein substrate (M.M. = 36 kDa) in human lymphocytes activated with concanavalin A (ConA). Similar effect on tyrosine-specific phosphorylation in mitogen-stimulated lymphocytes was observed with the native interferon or Cyclosporine A (CsA). Calcium fluxes induced by ConA in human lymphocytes were measured using a fluorescent calcium chelator Fura-2. In contrast to CsA, peptide 2438 did not affect the ConA-induced calcium influx in lymphocytes.

Interaction of a synthetic peptide of the interferon alpha 2 C-terminal part with human blood leukocytes. II. Effect on protein tyrosine phosphorylation.

Tyrosine phosphorylation in human blood lymphocytes was studied as a function of stimulation with concanavalin A (ConA) and treatment of the cells with interferon alpha 2 (IFN alpha 2) and/or an IFN-derived C-terminal synthetic peptide 2438 (amino acid residues 124-138). Both IFN alpha 2 and the peptide 2438 decreased the level of protein tyrosine phosphorylation in the ConA-stimulated cells. In unstimulated cells, IFN alpha 2 increased, and the peptide 2438 decreased the level of the tyrosine phosphorylation. A possible correlation of these effects with stimulation of cell proliferation is discussed.

Synthetic peptide with antiproliferative activity: a short C-terminal fragment of the human interferon alpha-2 molecule.

The biological activity of six synthetic peptides of the 124-144 region of the human interferon alpha-2 (IFN alpha-2) molecule was studied. Peptides were examined for their ability to inhibit mitogen induced proliferation of human blood cells in vitro. Only the peptide corresponding to the amino acid sequence 124-138 (2438) possessed IFN-like antiproliferative activity. Other tested synthetic peptides did not affect cell proliferation in this experimental system. As with the native IFN alpha-2 molecule, the inhibitory effect of the peptide 2438 was dose-dependent. On simultaneous addition of peptide 2438, antiproliferative activity of IFN alpha-2 was enhanced. Direct cytotoxic effects of synthetic peptide 2438 were not revealed. These results suggest that a synthetic peptide corresponding to the 124-138-amino acid sequence of the human IFN alpha-2 molecule serves as a cytostatic agent.

[Nucleotide sequence of the rplL gene coding for ribosomal protein L7/L12 of Pseudomonas putida]. / Nukleotidnaia posledovatel'nost' gena rplL, kodiruiushchego ribosomnyi belok L7/L12 Pseudomonas putida.

The Pseudomonas putida rpl L gene coding for ribosomal protein L7/L12 was cloned and sequenced. Although Asp55 residue in L7/L12 was previously shown to be conservative in ten different organisms, the Pseudomonas putida L7/L12 proved to contain Asn55, thus showing that Asp55 is not invariant.

[Genes coding for RNA polymerase in bacteria. III. The use of modified Sanger's method for sequencing the C-terminal region of rpoB gene, N-terminal region of rpoC gene and intercistron region of RNA polymerase in Pseudomonas putida]. / Geny, kodiruiushchie RNK-polimerazu bakterii. III. Ispol'zovanie modifitsirovannogo metoda Sengera dlia opredeleniia pervichnoi struktury C-kontsevoi oblasti gena rpoB, N-kontsevoi oblasti gena rpoC i mezhtsistronnogo uchastka RNK-polimerazy Pseudomonas putida.

The Sanger method was modified and the primary structure of the SalI-C fragment of the Pseudomonas putida rpoBC operon was elucidated.

[Amino acid substitutions in the beta-subunit of RNA-polymerase from E. coli compensating for mutation-induced damage of the rho termination factors]. / Aminokislotnye zameny v beta-sub''edinitse RNK-polimerazy E. coli, kompensiruiushchie mutatsionnye povrezhdeniia faktora terminatsii ro.

Ts-phenotype of the E. coli rho-factor mutant rho 15 is suppressed by two rifampicin-resistance mutations, rhoB1019 resulting in a single amino acid substitution Val146----Phe and rhoB268 resulting in a single substitution Gln513----Leu in beta-subunit of the E. coli RNA polymerase. Rifampicin-resistance mutations rhoB255 (Asp516----Val), rhoB1016 (Asp516----Asn), rhoB1001 (His526----Tyr), rhoB1004 (Ser531----Phe), rhoB1005 (Pro564----Leu), and streptolydigin-resistance' mutation rhoB1018 (double substitution Gly544----Asp and Phe545----Ser) do not suppress the rho15 mutation.

[Genes coding for RNA-polymerase in bacteria. II. Conservative sites in the central region of the beta-subunit of Pseudomonas putida RNA-polymerase]. / Geny, kodiruiushchie RNK-polimerazu bakterii. II. Konservativnye uchastki v tsentral'noi chasti beta-sub''edinitsy RNK-polimerazy Pseudomonas putida.

SalI--L fragment of the P. putida rpoBC operon has been sequenced and conservative regions of the central part of the RNA-polymerase beta-subunit have been determined. Amino and acid residues interacting with Zn2+ are postulated.

[Genes encoding bacterial RNA-polymerase. I. Cloning of rpoBC-operon of Pseudomonas putida and its physical map]. / Geny, kodiruiushchie RNK-polimerazu bakterii. I. Klonirovanie rpoBC-operona Pseudomonas putida i ego fizicheskaia karta.

The P. putida rpoBC operon, coding for beta and beta' subunits of RNA polymerase, was cloned and its physical map constructed.