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121.
Phenotypic variation and stress resistance in core and peripheral populations of Hordeum spontaneum 总被引:5,自引:0,他引:5
Sergei Volis Samuel Mendlinger Linda Olsvig-Whittaker Uriel N. Safriel Nikolay Orlovsky 《Biodiversity and Conservation》1998,7(6):799-813
The phenotypic variation and response of plants to water stress were studied in a field trial in populations of wild barley, Hordeum spontaneum Koch. from Israel and Turkmenistan. Populations from the species distributional core and periphery were compared and contrasted for phenotypic variation in 16 phenological and morphological traits. The peripheral populations (six) were found to be phenotypically more variable and more resistant to water stress than core populations (12). The association of water-stress resistance with high phenotypic variability gives support to the hypothesis that populations that are genetically more variable are better adapted or pre-adapted to environmental changes and are thus valuable for conservation. 相似文献
122.
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
123.
Sergei Grigoryan Michael B Yee Yair Glick Doron Gerber Eldad Kepten Yuval Garini In Hong Yang Paul R. Kinchington Ronald S. Goldstein 《PloS one》2015,10(5)
Varicella Zoster Virus (VZV), the alphaherpesvirus that causes varicella upon primary infection and Herpes zoster (shingles) following reactivation in latently infected neurons, is known to be fusogenic. It forms polynuclear syncytia in culture, in varicella skin lesions and in infected fetal human ganglia xenografted to mice. After axonal infection using VZV expressing green fluorescent protein (GFP) in compartmentalized microfluidic cultures there is diffuse filling of axons with GFP as well as punctate fluorescence corresponding to capsids. Use of viruses with fluorescent fusions to VZV proteins reveals that both proteins encoded by VZV genes and those of the infecting cell are transferred in bulk from infecting non-neuronal cells to axons. Similar transfer of protein to axons was observed following cell associated HSV1 infection. Fluorescence recovery after photobleaching (FRAP) experiments provide evidence that this transfer is by diffusion of proteins from the infecting cells into axons. Time-lapse movies and immunocytochemical experiments in co-cultures demonstrate that non-neuronal cells fuse with neuronal somata and proteins from both cell types are present in the syncytia formed. The fusogenic nature of VZV therefore may enable not only conventional entry of virions and capsids into axonal endings in the skin by classical entry mechanisms, but also by cytoplasmic fusion that permits viral protein transfer to neurons in bulk. 相似文献
124.
Counterintuitively, faster increases in human life expectancy could lead to slower population aging. The conventional view that faster increases in human life expectancy would lead to faster population aging is based on the assumption that people become old at a fixed chronological age. A preferable alternative is to base measures of aging on people’s time left to death, because this is more closely related to the characteristics that are associated with old age. Using this alternative interpretation, we show that faster increases in life expectancy would lead to slower population aging. Among other things, this finding affects the assessment of the speed at which countries will age. 相似文献
125.
Belén Hernández Yves‐Marie Coïc Bruno Baron Sergei G. Kruglik Fernando Pflüger Régis Cohen Claude Carelli Mahmoud Ghomi 《Biopolymers》2014,101(10):1019-1028
Lanreotide, a synthetic cyclic octapeptide, analogue of the peptide hormone somatostatin‐14 (SST‐14), is routinely used as a long‐acting medication in the management of neuroendocrine tumors. Despite its therapeutic importance, low concentration structural data is still lacking for lanreotide. In fact, the major part of the previous structural investigations were focused on the remarkable aggregation properties of this peptide, appearing at high concentrations (>5 mM). Here, we have applied three optical spectroscopic techniques, i.e. fluorescence, circular dichroism and Raman scattering, for analyzing the structural dynamics at the concentrations below 5 mM, where lanreotide exists either in a monomer state or at the first stages of aggregation. The obtained data from lanreotide were discussed through their comparison with those collected from SST‐14, leading us to the following conclusions: (i) The central D‐Trp residue, forming with its adjacent Lys the main receptor interacting part of lanreotide, keeps a constant high rotational freedom whatever the environment (water, water/methanol, methanol). (ii) A solvent‐dependent tight β‐turn, belonging to the type‐II' family, is revealed in lanreotide. (iii) Raman data analyzed by band decomposition in the amide (I and III) regions allowed estimation of different secondary structural elements within the millimolar range. Interestingly, the applied protocol shows a perfect agreement between the structural features provided by the amide I and amide III Raman markers. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1019–1028, 2014. 相似文献
126.
127.
Sergei A. Bobrovnik Miroslava Demchenko Sergei Komisarenko Fred Stevens 《Journal of molecular recognition : JMR》2010,23(5):448-456
Traditionally used methods of antibody affinity determination either by ELISA or by the surface plasmon resonance technique do not allow detection of the presence of low‐affinity antibodies in samples of high‐affinity antibodies. In this paper we demonstrate the possibility to reveal their presence and to determine the affinities of both categories of antibodies as well as the ratio of their concentrations. This is especially important since by using traditional methods for antibody affinity evaluation the admixture of low‐affinity antibodies in a sample diminishes the accuracy in determination of specific antibody affinity. In addition, the presence of an admixture of low‐affinity antibodies may be an important biological characteristic of the system under study; their revelation and the evaluation of their binding parameters may be valuable in many cases for obtaining a more complete characterization of the binding properties of the multiple antibodies generated in an immune response. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
128.
Andrei A. Krysko Olga L. Krysko Tatyana A. Kabanova Sergei A. Andronati Vladimir M. Kabanov 《Bioorganic & medicinal chemistry letters》2010,20(15):4444-4446
The novel RGDF mimetics were synthesized with the use of 4-(1,2,3,4-tetrahydroisoquinoline-7-yl)amino-4-oxobutyric or 5-(1,2,3,4-tetrahydroisoquinoline-7-yl)amino-5-oxopentanoic acids as a surrogate of Arg-Gly motif. The synthesized compounds have demonstrated a high potency to inhibit platelet aggregation in vitro and to block FITC-Fg binding to αIIbβ3 on washed human platelets. 相似文献
129.
Alexandre V. Ivachtchenko Eugen B. Frolov Oleg D. Mitkin Sergei E. Tkachenko Ilya M. Okun Alex V. Khvat 《Bioorganic & medicinal chemistry letters》2010,20(1):78-82
Syntheses, biological evaluation, and structure–activity relationships for a series of novel 5-styryl and 5-phenethyl analogs of dimebolin are disclosed. The novel derivatives and dimebolin share a broad spectrum of activities against therapeutically relevant targets. Among all synthesized derivatives, 2,8-dimethyl-5-[(Z)-2-phenylvinyl]-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole and its 5-phenethyl analog are the most potent blockers of 5-HT7, 5-HT6, 5-HT2C, Adrenergic α2 and H1 receptors. The general affinity rank order towards the studied receptors was Z-3(2) > 4(2) ? 4(3) ? dimebolin, all of them having highest affinities to 5-HT7 receptors. 相似文献
130.
In this study we use mtDNA ND2 gene (1041 bp) to evaluate the relationship between Menzbir’s (Anthus [gustavi] menzbieri) and Pechora (A. [g.] gustavi) pipits. Menzbir’s pipit is listed in the regional Red Data Book as a distinct, rare species with a small range. We obtained
18 Pechora pipit samples from two localities and 8 Menzbir’s pipit samples from a single locality. Sequences of the two taxa
appear reciprocally monophyletic and are separated by 6 substitutions (0.6% divergence). Differences between the taxa explained
62.4% of the variation in our dataset. Differences among individuals within localities explained 34.8%, whereas differences
between the two Pechora pipit localities explained only 2.8%. Mismatch distributions suggest that unlike the Pechora pipit
localities, which either have experienced recent population growth or sustain a stable population size, the Menzbir’s pipit
population may be declining. Our results suggest distinct taxonomic and conservation status for the Menzbir’s pipit. 相似文献