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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 《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
23.
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
24.
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
25.
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
26.
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
27.
We have established a high-frequency plant regeneration system via somatic embryogenesis from mature seeds of creeping bentgrass (Agrostis palustris Huds). The effects of 2,4-dichlorophenoxyacetic acid (2,4-D), 3.6-dichloroo-anisic acid (dicamba) and 6-benzyladenine (BA) on callus formation and embryogenesis were evaluated. Callus produced on the Murashige and Skoog (MS) (1962) medium containing 2,4-D had low embryogenic potency. In the presence of 30 M dicamba, addition of 2.25 to 9 M BA significantly enhanced embryogenic callus formation over dicamba alone. Optimum frequency of somatic embryogenesis was achieved on MS basal medium containing 30 M dicamba and 2.25 M BA. Over 80% of somatic embryos germinated and formed plantlets on half-strength MS basal medium. These plantlets grew normally in the greenhouse.Abbreviations MS
Murashige and Skoog medium
- 2,4-D
2,4-dichlorophenoxyacetic acid
- BA
6-benzyladenine
- dicamba
3, 6-dichloro-o-anisic acid 相似文献
28.
Mariam Lebbadi Antonio Gálvez Eva Valdivia Manuel Martínez-Blueno Mercedes Maqueda 《Archives of microbiology》1994,162(1-2):98-102
Three antibiotic peptides with amoebolytic activity have been purified from culture supernatants of Bacillus licheniformis M-4 (amoebicins m4-A, m4-B, and m4-C). They were hydrophilic peptides consisting of six different amino acids (Asp, Glu, Ser, Thr, Pro, Tyr). Their molecular weights ranged from 3,000 to 3,200. Purified amoebicins were active against human pathogenic and non-pathogenic strains of Naegleria. They also showed a broad antifungal spectrum, but a narrow antibacterial activity.Abbreviations (TFA)
Trifluoroacetic acid 相似文献
29.
Qian YW Schmidt RJ Zhang Y Chu S Lin A Wang H Wang X Beyer TP Bensch WR Li W Ehsani ME Lu D Konrad RJ Eacho PI Moller DE Karathanasis SK Cao G 《Journal of lipid research》2007,48(7):1488-1498
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protease that regulates low density lipoprotein receptor (LDLR) protein levels. The mechanisms of this action, however, remain to be defined. We show here that recombinant human PCSK9 expressed in HEK293 cells was readily secreted into the medium, with the prosegment associated with the C-terminal domain. Secreted PCSK9 mediated cell surface LDLR degradation in a concentration- and time-dependent manner when added to HEK293 cells. Accordingly, cellular LDL uptake was significantly reduced as well. When infused directly into C57B6 mice, purified human PCSK9 substantially reduced hepatic LDLR protein levels and resulted in increased plasma LDL cholesterol. When added to culture medium, fluorescently labeled PCSK9 was endocytosed and displayed endosomal-lysosomal intracellular localization in HepG2 cells, as was demonstrated by colocalization with DiI-LDL. PCSK9 endocytosis was mediated by LDLR as LDLR deficiency (hepatocytes from LDLR null mice), or RNA interference-mediated knockdown of LDLR markedly reduced PCSK9 endocytosis. In addition, RNA interference knockdown of the autosomal recessive hypercholesterolemia (ARH) gene product also significantly reduced PCSK9 endocytosis. Biochemical analysis revealed that the LDLR extracellular domain interacted directly with secreted PCSK9; thus, overexpression of the LDLR extracellular domain was able to attenuate the reduction of cell surface LDLR levels by secreted PCSK9. Together, these results reveal that secreted PCSK9 retains biological activity, is able to bind directly to the LDLR extracellular domain, and undergoes LDLR-ARH-mediated endocytosis, leading to accelerated intracellular degradation of the LDLR. 相似文献
30.
Benter IF Yousif MH Cojocel C Al-Maghrebi M Diz DI 《American journal of physiology. Heart and circulatory physiology》2007,292(1):H666-H672
The aim of this study was to test the hypothesis that treatment with angiotensin-(1-7) [ANG-(1-7)] or ANG-(1-7) nonpeptide analog AVE-0991 can produce protection against diabetes-induced cardiovascular dysfunction. We examined the influence of chronic treatment (4 wk) with ANG-(1-7) (576 microg.kg(-1).day(-1) ip) or AVE-0991 (576 microg.kg(-1).day(-1) ip) on proteinuria, vascular responsiveness of isolated carotid and renal artery ring segments and mesenteric bed to vasoactive agonists, and cardiac recovery from ischemia-reperfusion in streptozotocin-treated rats (diabetes). Animals were killed 4 wk after induction of diabetes and/or treatment with ANG-(1-7) or AVE-0991. There was a significant increase in urine protein (231 +/- 2 mg/24 h) in diabetic animals compared with controls (88 +/- 6 mg/24 h). Treatment of diabetic animals with ANG-(1-7) or AVE-0991 resulted in a significant reduction in urine protein compared with vehicle-treated diabetic animals (183 +/- 16 and 149 +/- 15 mg/24 h, respectively). Treatment with ANG-(1-7) or AVE-0991 also prevented the diabetes-induced abnormal vascular responsiveness to norepinephrine, endothelin-1, angiotensin II, carbachol, and histamine in the perfused mesenteric bed and isolated carotid and renal arteries. In isolated perfused hearts, recovery of left ventricular function from 40 min of global ischemia was significantly better in ANG-(1-7)- or AVE-0991-treated animals. These results suggest that activation of ANG-(1-7)-mediated signal transduction could be an important therapeutic strategy to reduce cardiovascular events in diabetic patients. 相似文献