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91.
Vsevolod A. Tverdislov Salam El Karadaghi Doris J. Bucher Juri A. Zakomirdin Igor G. Kharitonenkov 《生物化学与生物物理学报:生物膜》1984,778(2):276-280
The dependence of the surface potential difference (ΔU), transversal elasticity module (E1) and membrane conductivity (G0) on the concentrations of the antiviral drugs, rimantadine and amantadine was studied in the planar bilayer lipid membrane system. The method used was based on independent measurements of the second and third harmonics of the membrane capacitance current. The binding constants of bilayer lipid membranes obtained from the drug adsorption isotherms were 2.1 · 105 M?1 and 1.3 · 104 M?1 for rimantadine and amantadine, respectively. The changes in G0 took place only after drug adsorption saturation had been achieved. The influence of rimantadine and amantadine on the interaction of bilayer lipid membranes with matrix protein from influenza virus was also investigated. The presence of 70 μg/ml rimantadine in the bathing solution resulted in an increase in the concentration of M-protein at which the adsorption and conductance changes were observed. The effects of amantadine were similar to those of rimantadine but required a higher critical concentration of amantadine. The results obtained suggest that the antiviral properties of rimantadine and amantadine may be related to the interaction of these drugs with the cell membrane, which can affect virus penetration into the cell as well as maturation of the viral particle at the cell membrane. 相似文献
92.
Helen E Gruber Igor J Puzanov Michael Bennett Vinay Kumar Brian Gordon 《BMC cell biology》2001,2(1):3
Background
Although the role of the osteoclast in bone resorption is becoming better understood, much remains to be learned about osteoclastogenesis and the exact mechanism of action of anti-resorbing agents such as 17β-estradiol. This study investigated bone and morphologic osteoclast alterations following long-term estrogen administration to the B6D2F1 mouse. B6D2F1 mice aged 4-5 weeks were exposed to high levels of estrogen via implanted silastic tubing for at least 12 weeks; controls received empty tubing. Femurs of control and treated mice were assessed with radiology, quantitative histomorphometry and transmission electron microscopy. 相似文献93.
Characterization of Nine Novel Mutations in the CD40 Ligand Gene in Patients with X-Linked Hyper IgM Syndrome of Various Ancestry 总被引:3,自引:0,他引:3 下载免费PDF全文
Paolo Macchi Anna Villa Dario Strina Maria Grazia Sacco Federica Morali Duilio Brugnoni Silvia Giliani Elide Mantuano Anders Fasth Bengt Andersson Ben J. M. Zegers Giovanni Cavagni Igor Reznick Jacov Levy Israel Zan-Bar Yael Porat Paolo Air Alessandro Plebani Paolo Vezzoni Luigi D. Notarangelo 《American journal of human genetics》1995,56(4):898-906
X-linked immunodeficiency with hyper-IgM (HIGMX-1) is a rare disorder caused by defective expression of the CD40 ligand (CD40L) by activated T lymphocytes, resulting in inefficient T-B cell cooperation and failure of B cells to undergo immunoglobulin isotype switch. In the present work, we describe nine patients of various ancestry who bear different mutations in the X chromosome–specific CD40L gene. Two of the mutations were nonsense mutations, one each resulting in premature stop codons at amino acid residues 39 and 140. Three patients had single point missense mutations, one each at codons 126, 140, and 144. Another patient had a 4-bp genomic deletion in exon 2, resulting in a frameshift and premature termination. Three patients showed insertions, one each of 1, 2, and 4 nt, probably because of polymerase slippage, resulting in frameshift mutation and premature termination. Overall, these observations confirm the heterogeneity of mutations in HIGMX-1. However, the identification of two patients whose mutation involves codon 140 (previously shown to be altered in two other unrelated subjects) suggests that this may be a hotspot of mutation in HIGMX-1. In two additional patients with clinical and immunological features indistinguishable from canonical HIGMX-1, no mutation was detected in the coding sequence, in the 5' flanking region, or in the 3' UTR. 相似文献
94.
Background
Enzymes involved in DNA metabolic events of the highly radioresistant bacterium Deinococcus radiodurans are currently examined to understand the mechanisms that protect and repair the Deinococcus radiodurans genome after extremely high doses of γ-irradiation. Although several Deinococcus radiodurans DNA repair enzymes have been characterised, no biochemical data is available for DNA ligation and DNA endhealing enzymes of Deinococcus radiodurans so far. DNA ligases are necessary to seal broken DNA backbones during replication, repair and recombination. In addition, ionizing radiation frequently leaves DNA strand-breaks that are not feasible for ligation and thus require end-healing by a 5'-polynucleotide kinase or a 3'-phosphatase. We expect that DNA ligases and end-processing enzymes play an important role in Deinococcus radiodurans DNA strand-break repair. 相似文献95.
Marcelo Neves de Medeiros Bruno César C. Soares Cláudio Canetti Clarissa Menezes Maya-Monteiro Igor C. Almeida Eleonora Kurtenbach 《Journal of insect physiology》2009,55(2):151-158
In this work we characterized the immune response of the insect Rhodnius prolixus to a direct injection into the hemocoel of the non-entomopathogenic fungus Aspergillus niger, and evaluated its consequences on host oogenesis. These animals were able to respond by mounting effective cellular and humoral responses to this fungus; these responses were shown, however, to have reproductive fitness costs, as the number of eggs laid per female was significantly reduced. The disturbance of egg formation during infectious process correlated with an elevation in the titer of hemolymph prostaglandin E2 48 h post-challenge. Administration of Zymosan A as an immunogenic non-infectious challenge produced similar effects on phenoloxidase and prophenoloxidase activities, oocyte development and prostaglandin E2 titer, precluding the hypothesis of an effect mediated by fungal metabolites in animals challenged with fungus. Ovaries at 48 h post-challenge showed absence of vitellogenic ovarian follicles, and the in vivo administration of prostaglandin E2 or its receptor agonist misoprostol, partially reproduced this phenotype. Together these data led us to hypothesize that immune-derived prostaglandin E2 raised from the insect response to the fungal challenge is involved in disturbing follicle development, contributing to a reduction in host reproductive output and acting as a host-derived adaptive effector to infection. 相似文献
96.
Igor N. Sergeev 《Biochemical and biophysical research communications》2009,384(1):18-21
Induction of apoptotic cell death is emerging as a promising strategy for prevention and treatment of obesity because removing of adipocytes via apoptosis may result in reducing body fat and a long-lasting maintenance of weight loss. However, the mechanisms controlling adipocyte apoptosis are unknown and even the ability of adipocytes to undergo apoptosis has not been conclusively demonstrated. We have shown previously that the specific Ca2+ signal, sustained increase in intracellular Ca2+, triggers apoptotic cell death via activation of Ca2+-dependent proteases and that the apoptosis-inducing effect of the hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is mediated through Ca2+ signaling. Here, we report that 1,25(OH)2D3 induces apoptosis in mature mouse 3T3-L1 adipocytes via activation of Ca2+-dependent calpain and Ca2+/calpain-dependent caspase-12. Treatment of adipocytes with 1,25(OH)2D3 induced, in concentration- and time-dependent fashion, a sustained increase in the basal level of intracellular Ca2+. The increase in Ca2+ was associated with induction of apoptosis and activation of μ-calpain and caspase-12. Our results demonstrate that Ca2+-mediated apoptosis can be induced in mature adipocytes and that the apoptotic molecular targets activated by 1,25(OH)2D3 in these cells are Ca2+-dependent calpain and caspase-12. These findings provide rationale for evaluating the role of vitamin D in prevention and treatment of obesity. 相似文献
97.
Luciana Albuquerque Catarina Ferreira David Tomaz Igor Tiago António Veríssimo Milton S. da Costa M. Fernanda Nobre 《Systematic and applied microbiology》2009
Four red-pigmented isolates, with optimum growth temperatures of approximately 55–60 °C and an optimum pH for growth between 7.5 and 8.5, were recovered from hot springs in Central France. Phylogenetic analysis of the 16S rRNA gene sequences showed that these organisms represented a new species of the genus Meiothermus. The new isolates could be distinguished from other strains of the species of the genus Meiothermus primarily by the glycolipid profile and fatty acid composition because these organisms lacked the hydroxy fatty acids and the glycolipid variant GL-1a found in all other isolates of the species of Meiothermus examined. On the basis of the results presented here we propose the name Meiothermus rufus for the new species, which is represented by strains CAL-4T (=DSM 22234T=LMG 24878T) and CAL-12 (=DSM 22235=LMG 24879). We also propose emending the genus Meiothermus to include strains that have only one glycolipid instead of two glycolipid variants. 相似文献
98.
Coral Reefs - Due to the dearth of molecular markers variable enough to distinguish species of black corals, species delimitation in Antipatharia is still mainly based on morphological traits. One... 相似文献
99.
Vanden Wymelenberg A Minges P Sabat G Martinez D Aerts A Salamov A Grigoriev I Shapiro H Putnam N Belinky P Dosoretz C Gaskell J Kersten P Cullen D 《Fungal genetics and biology : FG & B》2006,43(5):343-356
The white-rot basidiomycete Phanerochaete chrysosporium employs extracellular enzymes to completely degrade the major polymers of wood: cellulose, hemicellulose, and lignin. Analysis of a total of 10,048 v2.1 gene models predicts 769 secreted proteins, a substantial increase over the 268 models identified in the earlier database (v1.0). Within the v2.1 'computational secretome,' 43% showed no significant similarity to known proteins, but were structurally related to other hypothetical protein sequences. In contrast, 53% showed significant similarity to known protein sequences including 87 models assigned to 33 glycoside hydrolase families and 52 sequences distributed among 13 peptidase families. When grown under standard ligninolytic conditions, peptides corresponding to 11 peptidase genes were identified in culture filtrates by mass spectrometry (LS-MS/MS). Five peptidases were members of a large family of aspartyl proteases, many of which were localized to gene clusters. Consistent with a role in dephosphorylation of lignin peroxidase, a mannose-6-phosphatase (M6Pase) was also identified in carbon-starved cultures. Beyond proteases and M6Pase, 28 specific gene products were identified including several representatives of gene families. These included 4 lignin peroxidases, 3 lipases, 2 carboxylesterases, and 8 glycosyl hydrolases. The results underscore the rich genetic diversity and complexity of P. chrysosporium's extracellular enzyme systems. 相似文献
100.
Here we analyzed the influence of salt stress on plant genome stability. Homologous recombination events were detected in transgenic Arabidopsis plants that carried in their genome a beta-glucuronidase recombination marker. Recombination events were scored as blue sectors using a stereo microscope. Exposure to 50 mM salt resulted in a 3.0-fold increase in recombination frequency. To analyze the organ and tissue specificity of recombination events, we examined cross-sections of leaves, stems and roots. We found that nearly 30% of recombination events in plants grown under normal conditions and nearly 50% of events in plants grown on salt were undetected by the conventional method. Most of the recombination events represented a cluster/group of cells (12 on average), although events with single cells were also detected. Recombination events were very frequent in leaf mesophyll cells. On average, individual recombination events located on leaves contained more cells than events located on roots or stems. Analysis of recombination events in cross-sectioned tissue of salt-treated plants revealed a shift in the distribution of recombination events towards the vascular tissue. We discuss the significance of the finding for plant stress physiology. 相似文献