A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Lethal and mutagenic action of N-nitroso-N-methylbiuret on the producers of levorin, amphotericin and mycoheptin]

The lethal and mutagenic effect of N-nitrozo-N-methylbiuret (NMB) on the organisms producing levorin, amphotericin B and mycoheptin was studied. The mutagen effect depended on the dose, culture and physiological state of the spores. NMB had a low mutagenic effect on the levorin-producing organism characterized by high activity and genetic homogenicity with respect to the colony morphology and antibiotic production. As for the organisms producing amphotericin B and mycoheptin characterized by high genetic heterogenicity, significant variation of all the features studied was observed on their exposure to the mutagen. Inspite of diverse reaction of the organisms producing levorin, amphotericin B and mycoheptin to the effect of NMB mutants with increased antibiotic production were obtained from the three cultures. The lethal and mutagenic effect of NMB on the mycoheptin-producing organism depended on the process of the spore DNA replication. The spores during the DNA replication period were least sensitive to the lethal effect of the mutagen and most mutable with the respect to the colony morphology. For selection of highly active and stable strains exposure to NMB of the spores of the mycoheptin-producing organism during replication of DNA proved to be more effective than that of the spores during the lag-phase.     

Involvement of ionotropic glutamate receptors in the genesis of arecoline-induced tremor

The muscarinic agonist arecoline (6 mg/kg, subcutaneously in mice) induced a long-lasting tremor. The inhibitory potency of non-competitive antagonists of ionotropic glutamate receptors has been studied. These antagonists are the derivatives of adamantane and phenylcyclohexyl. A part of them: monocationic compounds, selectively block the NMDA-receptor channels, their dicationic analogues affecting both channels of the NMDA- and the AMPA-glutamate receptors. Monocationic blockers effectively reduced the arecoline-evoked tremor and their potency correlated with ability to block the NMDA-receptor channels. Dicationic blockers revealed protective effect only in low range doses (0.0001-0.01 microM/kg). Further increase of the dose reduced or completely abolished this effect. This suggests that the NMDA-receptors are involved in the genesis of arecoline-evoked tremor. The only moderate blockade of the AMPA-receptors potentiates the drug blocking action but the prevalent blockade of these receptors impedes the effect on arecoline-evoked tremor.     

Effects of blockade of ionotropic glutamate receptors on the development of pentylenetetrazole kindling in mice

Effects of mono- and dicationic derivatives of adamantane and phenylcyclohexyl on the petyleneterazole-induced (35 mg/kg i. p.) kindling were studied in the experiments on mice. Monocationic derivative of phenylcyclohexyl IEM-1921, effectively retarded the development of kindling beginning the dose 0.0001 microM/kg. Memantine: derivative of adamantane (derivative of adamatane) produced the same effect with 100-fold increased dose. Dicationic derivative ofphenylcyclohexyl: IEM-1925, is able to block equally the open channels of both NMDA and subtype of Ca-permeable AMPA receptors. Its effect on kindling differed markedly from selective NMDA antagonists (IEM-1921 and memantine) in more complicated dose-dependence. The retardation of kindling IEM-1925 was induced at 0.001 microM/kg. On the contrary, a 10-time lower dose: 0.0001 microM/kg, facilitated the development of kindling. The observed difference in the activity of selective NMDA antagonists and the drugs combining anti-NMDA and anti-AMPA potency indicates that both types of ionotropic glutamate receptors are involved in the mechanism of petyleneterazole-induced kindling. The integral effect of channel blockade evoked by drugs seems to be dependent not only upon the ratio of the receptor types but on the kinetics of drug action, too.     

Nuclease biosynthesis and growth of Serratia marcescens in the presence of 2-(p-aminobenzenesulfonamide)-thiazole

The biosynthesis of nuclease in Serratia marcescens has been studied under the conditions of purine synthesis inhibition with 2-(p-aminobenzenesulfonamide)-thiazole. The addition of this sulfonamide to S. marcescens at different growth stages is found to inhibit both culture growth and nuclease synthesis.     

Nuclease Biosynthesis and Growth of <Emphasis Type="Italic">Serratia marcescens</Emphasis> in the Presence of 2-(<Emphasis Type="Italic">p</Emphasis>-Aminobenzenesulfonamide)-thiazole

The biosynthesis of nuclease in Serratia marcescens has been studied under the conditions of purine synthesis inhibition with 2-(p-aminobenzenesulfonamide)-thiazole. The addition of this sulfonamide to S. marcescens at different growth stages is found to inhibit both culture growth and nuclease synthesis.__________Translated from Mikrobiologiya, Vol. 74, No. 3, 2005, pp. 365–369.Original Russian Text Copyright © 2005 by Starshinova, Filimonova.     

AmylPepPred: Amyloidogenic Peptide Prediction tool

We present an efficient computational architecture designed using supervised machine learning model to predict amyloid fibril forming protein segments, named AmylPepPred. The proposed prediction model is based on bio-physio-chemical properties of primary sequences and auto-correlation function of their amino acid indices. AmylPepPred provides a user friendly web interface for the researchers to easily observe the fibril forming and non-fibril forming hexmers in a given protein sequence. We expect that this stratagem will be highly encouraging in discovering fibril forming regions in proteins thereby benefit in finding therapeutic agents that specifically aim these sequences for the inhibition and cure of amyloid illnesses.

Availability

AmylPepPred is available freely for academic use at www.zoommicro.in/amylpeppred