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21.
We present here the genetic structure existing among five samples of the spotted sea bass Dicentrarchus punctatus, and we compare it to what prevails in the common sea bass D. labrax, a congeneric species sampled on almost the same geographical range. A genetic distance tree inferred from the polymorphism at six microsatellite loci shows a distinct pattern for the two species. D. labrax samples appears to be genetically more homogeneous with a global Fst of 3% as compared to the 10% observed at D. punctatus, indicating a lesser level of gene flow in the latter species. While appearing more differentiated, D. punctatus presents no clear geographical organisation of its genetic variability in opposition to D. labrax samples. This allows us to propose this pair of closely relative species as a good candidate for the study by comparative analysis of the biological and/or historical factors affecting genetic differentiation in marine environment. 相似文献
22.
Sergei Andreev Igor Andreev Elena Nikolaeva Anna Petrukhina Vladimir Zemskov Mariam Vafina 《Letters in Peptide Science》1998,5(2-3):63-66
The V3 loop from HIV-1 envelope glycoprotein gp120 is involved in viral entry and determines the cellular tropism and HIV-1-induced cell–cell fusion. Earlier we have shown that V3 loop peptides representing the sequences of syncytia-inducing HIV strains have high membranotropic activity. These peptides caused the lysis of liposomes of various lipid compositions, could fuse negatively charged liposomes and induced hemolysis of erythrocytes. In contrast, peptides mimicking the sequences of non-syncytia-inducing viruses showed no lytic or fusion activities at the same concentrations. Now we have found that the V3 loop synthetic peptides containing the conserved GPGR region, derived from T-lymphotropic strains (BRU and MN), as opposed to peptides containing the GPGQ region, are able to cause a pronounced membrane permeabilization (dissipation of the pH and the of human peripheral blood lymphocytes, erythrocytes and plasma membrane vesicles at micromolar concentrations with a dose-dependent kinetics. Analysis of the secondary structures of the peptides by circular dichroism revealed conformational changes in V3 loop peptides depending on solvent hydrophobicity: from random coil in water to an -helix/-sheet conformation in trifluoroethanol. Such structural changes of the V3 loop together with the membrane insertion of the gp41 N-terminal fusion peptide may promote the formation of the fusion pore during virus–cell fusion. 相似文献
23.
The DNA sequence of a 7.8-kb Helicobacter pylori plasmid, pHPM8, was determined. Six open reading frames (ORFs) were present. Ribonuclease protection studies showed that ORF1/ORF2 and ORF3/ORF4 genes are organized in operons possibly involved in plasmid replication and in production of a peptide with antibiotic activity, respectively. Finding areas of pHPM8 with a high level of identity to H. pylori chromosomal DNA supported the hypothesis that recombination occurs between plasmids and the chromosome of H. pylori. 相似文献
24.
Sergei Andreev Igor Andreev Elena Nikolaeva Anna Petrukhina Vladimir Zemskov Mariam Vafina 《International journal of peptide research and therapeutics》1998,5(2-3):63-66
Summary The V3 loop from HIV-1 envelope glycoprotein gp120 is involved in viral entry and determines the cellular tropism and HIV-1-induced
cell-cell fusion. Earlier we have shown that V3 loop peptides representing the sequences of syncytia-inducing HIV strains
have high membranotropic activity. These peptides caused the lysis of liposomes of various lipid compositions, could fuse
negatively charged liposomes and induced hemolysis of erythrocytes. In contrast, peptides mimicking the sequences of non-syncytia-inducing
viruses showed no lytic or fusion activities at the same concentrations. Now we have found that the V3 loop synthetic peptides
containing the conserved GPGR region, derived from T-lymphotropic strains (BRU and MN), as opposed to peptides containing
the GPGQ region, are able to cause a pronounced membrane permeabilization (dissipation of the ΔpH and the Δψ) of human peripheral
blood lymphocytes, erythrocytes and plasma membrane vesicles at micromolar concentrations with a dose-dependent kinetics.
Analysis of the secondary structures of the peptides by circular dichroism revealed conformational changes in V3 loop peptides
depending on solvent hydrophobicity: from random coil in water to an α-helix/β-sheet conformation in trifluoroethanol. Such
structural changes of the V3 loop together with the membrane insertion of the gp41 N-terminal fusion peptide may promote the
formation of the fusion pore during virus-cell fusion. 相似文献
25.
Muhammad Farooq Sabar Mustansara Yaqub Mohsin Ahmad Khan Nadeem Ahmad Muhammad Usman Ghani Mariam Shahid 《International journal of peptide research and therapeutics》2010,16(4):239-245
Efficacy of proteins can be enhanced by using polyethylene glycol (PEG) conjugation (PEGylation) to the protein molecules.
Mobile non-toxic PEG chains conjugated to bio-therapeutics increase their hydrodynamic volume and in turn can prolong their
plasma retention time and increase their solubility. An important aspect of PEGylation is the selection of PEG molecule with
suitable structure and molecular weight. In this study, conceiving the idea that branched PEG-conjugates show superior efficacy
over the linear PEG-conjugates, a tri-branched PEG-interferon (mPEG3L2-IFN) was synthesized by reacting a 30 KDa tri-branched mPEG3L2-NHS reagent with IFN to improve its pharmacokinetic properties and reduce the loss of in vitro bioactivity (which is generally
exhibited by PEGylation) of the conjugated protein to some extent. The PEGylation procedure was optimized in terms of concentration
and molar ratios of reactants, reaction time, temperature and pH conditions of the reaction mix. The conjugate was purified
by cation exchange chromatography and characterized by SDS-PAGE and SE-HPLC. Trypsin digestion of mPEG3L2-IFN indicated a single site specificity of PEGylation. Anti viral bioactivity of mPEG3L2-IFN was found to be 2.38 × 107 IU/mg which is approximately 9.52% of native IFNα2 (2.5 × 108 IU/mg) and better than PEGasys from Roche Pharma. Therefore, it is reported that the tri-branched mPEG3L2-NHS reagent has the potential to be used to conjugate proteins for the promising therapeutic results. 相似文献
26.
Mahmood Hossain Siddique Mohammad Raqibul Hasan Rubaiot Abdullah S. M. Costello Liam Matieu Henry Iqbal Md. Zaheer Akhter Mariam 《Wetlands Ecology and Management》2019,27(4):553-569
Wetlands Ecology and Management - Bangladesh has the single largest tract of naturally growing mangrove forest as well as the world’s largest manmade mangrove forest on newly accreted land in... 相似文献
27.
Forouhar F Kuzin A Seetharaman J Lee I Zhou W Abashidze M Chen Y Yong W Janjua H Fang Y Wang D Cunningham K Xiao R Acton TB Pichersky E Klessig DF Porter CW Montelione GT Tong L 《Journal of structural and functional genomics》2007,8(2-3):37-44
Structural genomics efforts have produced structural information, either directly or by modeling, for thousands of proteins
over the past few years. While many of these proteins have known functions, a large percentage of them have not been characterized
at the functional level. The structural information has provided valuable functional insights on some of these proteins, through
careful structural analyses, serendipity, and structure-guided functional screening. Some of the success stories based on
structures solved at the Northeast Structural Genomics Consortium (NESG) are reported here. These include a novel methyl salicylate
esterase with important role in plant innate immunity, a novel RNA methyltransferase (H. influenzae yggJ (HI0303)), a novel spermidine/spermine N-acetyltransferase (B. subtilis PaiA), a novel methyltransferase or AdoMet binding protein (A. fulgidus AF_0241), an ATP:cob(I)alamin adenosyltransferase (B. subtilis YvqK), a novel carboxysome pore (E. coli EutN), a proline racemase homolog with a disrupted active site (B. melitensis BME11586), an FMN-dependent enzyme (S. pneumoniae SP_1951), and a 12-stranded β-barrel with a novel fold (V. parahaemolyticus VPA1032). 相似文献
28.
29.
Cyanobacterial NDH-1 is a multisubunit complex involved in proton translocation, cyclic electron flow around photosystem I and CO2 uptake. The function and location of several of its small subunits are unknown. In this work, the location of the small subunits NdhL, -M, -N, -O and CupS of Synechocystis 6803 NDH-1 was established by electron microscopy (EM) and single particle analysis. To perform this, the subunits were enlarged by fusion with the YFP protein. After classification of projections, the position of the YFP tag was revealed; all five subunits are integrated in the membrane domain. The results on NDH-1 demonstrate that a GFP tag can be revealed after data processing of EM data sets of moderate size, thus showing that this way of labeling is a fast and reliable way for subunit mapping in multisubunit complexes after partial purification. 相似文献
30.
A recent antineoplastic medication is pemetrexed, this medicine is now being developed and produced on a large scale, thus approaches for quality control are urgently needed. Spectrofluorimetric guidelines for the simple estimation of pemetrexed were validated. Pemetrexed's assay depends on observations of its native fluorescence at wavelengths 275/450 nm and pH 4. The proposed approach was also used to identify the examined drug in both its formulation and in human plasma that had been spiked. 相似文献