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排序方式: 共有131条查询结果,搜索用时 638 毫秒
71.
Christian Wasmer Raimon Sabaté Alice Soragni Christiane Ritter 《Journal of molecular biology》2010,402(2):311-325
We describe a distant homologue of the fungal HET-s prion, which is found in the fungus Fusarium graminearum. The domain FgHET-s(218-289), which corresponds to the prion domain in HET-s from Podospora anserina, forms amyloid fibrils in vitro and is able to efficiently cross-seed HET-s(218-289) prion formation. We structurally characterize FgHET-s(218-289), which displays 38% sequence identity with HET-s(218-289). Solid-state NMR and hydrogen/deuterium exchange detected by NMR show that the fold and a number of structural details are very similar for the prion domains of the two proteins. This structural similarity readily explains why cross-seeding occurs here in spite of the sequence divergence. 相似文献
72.
So far, POM121 and gp210 are the only known anchoring sites of vertebrate nuclear pore complexes (NPCs) within the lipid bilayer of the nuclear envelope (NE) and, thus, are excellent candidates for initiating the NPC assembly process. Indeed, we demonstrate that POM121 can recruit several nucleoporins, such as Nup62 or Nup358, to ectopic assembly sites. It thus appears to act as a nucleation site for the assembly of NPC substructures. Nonetheless, we observed functional NPCs and intact NEs in severely POM121-depleted cells. Double knockdowns of gp210 and POM121 in HeLa cells, as well as depletion of POM121 from human fibroblasts, which do not express gp210, further suggest that NPCs can assemble or at least persist in a POM121- and gp210-free form. This points to extensive redundancies in protein-protein interactions within NPCs and suggests that vertebrate NPCs contain additional membrane-integral nucleoporins for anchorage within the lipid bilayer of the NE. In Stavru et al., we describe such an additional transmembrane nucleoporin as the metazoan orthologue of yeast Ndc1p. 相似文献
73.
Allice T Cerutti F Pittaluga F Varetto S Gabella S Marzano A Franchello A Ghisetti V 《The new microbiologica》2008,31(1):27-35
Performances of the new automatic system COBAS AmpliPrep/COBAS TaqMan 48 (CAP/CTM) (Roche, Branchburg, NJ) for HBV DNA extraction and real-time PCR quantification were assessed and compared with the endpoint PCR COBAS AMPLICOR HBV Monitor (CAHBM, Roche). Analytical evaluation with proficiency panels from UK National External Quality Assessment Scheme (UK NEQAS) over a 1-year period of distribution showed that CAP/CTM correctly measured HBV DNA levels with a close correlation between expected and observed values (r=0.995). Clinical evaluation as tested with samples from 11 HBsAg-positive patients undergoing antiviral therapy (71 serial specimens of plasma), demonstrated excellent correlation with CAHBM (r=0.958, mean difference in quantitation: 0.14 log, IU/ml), but CAP/CTM detected longer period of residual viremia. HBV DNA reduction was much higher in the combination schedule (Lamivudine+Adefovir), than in Adefovir monotherapy (5.1 vs. 3.5 logs). In conclusion, CAP/CTM allows for an accurate and standardized quantification of HBV DNA in high through-put laboratories. Due to it high sensitivity, it may further improve the detection of emerging drug resistance strains and the assessment of antiviral therapy. 相似文献
74.
Lauro C Di Angelantonio S Cipriani R Sobrero F Antonilli L Brusadin V Ragozzino D Limatola C 《Journal of immunology (Baltimore, Md. : 1950)》2008,180(11):7590-7596
The chemokine fractalkine (CX(3)CL1) is constitutively expressed by central neurons, regulating microglial responses including chemotaxis, activation, and toxicity. Through the activation of its own specific receptor, CX(3)CR1, CX(3)CL1 exerts both neuroprotection against glutamate (Glu) toxicity and neuromodulation of the glutamatergic synaptic transmission in hippocampal neurons. Using cultured hippocampal neuronal cell preparations, obtained from CX(3)CR1(-/-) (CX(3)CR1(GFP/GFP)) mice, we report that these same effects are mimicked by exposing neurons to a medium conditioned with CX(3)CL1-treated mouse microglial cell line BV2 (BV2-st medium). Furthermore, CX(3)CL1-induced neuroprotection from Glu toxicity is mediated through the adenosine receptor 1 (AR(1)), being blocked by neuronal cell preparations treatment with 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), a specific inhibitor of AR(1), and mimicked by both adenosine and the specific AR(1) agonist 2-chloro-N(6)-cyclopentyladenosine. Similarly, experiments from whole-cell patch-clamped hippocampal neurons in culture, obtained from CX(3)CR1(+/+) mice, show that CX(3)CL1-induced depression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid- (AMPA-) type Glu receptor-mediated current (AMPA-current), is associated with AR(1) activity being blocked by DPCPX and mimicked by adenosine. Furthermore, BV2-st medium induced a similar AMPA-current depression in CX(3)CR1(GFP/GFP) hippocampal neurons and this depression was again blocked by DPCPX. We also report that CX(3)CL1 induced a significant release of adenosine from microglial BV2 cells, as measured by HPLC analysis. We demonstrate that (i) CX(3)CL1, along with AR(1), are critical players for counteracting Glu-mediated neurotoxicity in the brain and (ii) AR(1) mediates neuromodulatory action of CX(3)CL1 on hippocampal neurons. 相似文献
75.
76.
Fabrizia Carofiglio Akiko Inagaki Sandra de Vries Evelyne Wassenaar Sam Schoenmakers Christie Vermeulen Wiggert A. van Cappellen Esther Sleddens-Linkels J. Anton Grootegoed Hein P. J. te Riele Bernard de Massy Willy M. Baarends 《PLoS genetics》2013,9(6)
In mammalian meiotic prophase, the initial steps in repair of SPO11-induced DNA double-strand breaks (DSBs) are required to obtain stable homologous chromosome pairing and synapsis. The X and Y chromosomes pair and synapse only in the short pseudo-autosomal regions. The rest of the chromatin of the sex chromosomes remain unsynapsed, contains persistent meiotic DSBs, and the whole so-called XY body undergoes meiotic sex chromosome inactivation (MSCI). A more general mechanism, named meiotic silencing of unsynapsed chromatin (MSUC), is activated when autosomes fail to synapse. In the absence of SPO11, many chromosomal regions remain unsynapsed, but MSUC takes place only on part of the unsynapsed chromatin. We asked if spontaneous DSBs occur in meiocytes that lack a functional SPO11 protein, and if these might be involved in targeting the MSUC response to part of the unsynapsed chromatin. We generated mice carrying a point mutation that disrupts the predicted catalytic site of SPO11 (Spo11YF/YF), and blocks its DSB-inducing activity. Interestingly, we observed foci of proteins involved in the processing of DNA damage, such as RAD51, DMC1, and RPA, both in Spo11YF/YF and Spo11 knockout meiocytes. These foci preferentially localized to the areas that undergo MSUC and form the so-called pseudo XY body. In SPO11-deficient oocytes, the number of repair foci increased during oocyte development, indicating the induction of S phase-independent, de novo DNA damage. In wild type pachytene oocytes we observed meiotic silencing in two types of pseudo XY bodies, one type containing DMC1 and RAD51 foci on unsynapsed axes, and another type containing only RAD51 foci, mainly on synapsed axes. Taken together, our results indicate that in addition to asynapsis, persistent SPO11-induced DSBs are important for the initiation of MSCI and MSUC, and that SPO11-independent DNA repair foci contribute to the MSUC response in oocytes. 相似文献
77.
Ellen AF Rohulya OV Fusetti F Wagner M Albers SV Driessen AJ 《Journal of bacteriology》2011,193(17):4380-4387
Crenarchaea, such as Sulfolobus acidocaldarius and Sulfolobus tokodaii, produce antimicrobial proteins called sulfolobicins. These antimicrobial proteins inhibit the growth of closely related species. Here we report the identification of the sulfolobicin-encoding genes in S. acidocaldarius. The active sulfolobicin comprises two proteins that are equipped with a classical signal sequence. These proteins are secreted by the cells and found to be membrane vesicle associated. Gene inactivation studies demonstrate that both proteins are required for the bacteriostatic antimicrobial activity. Sulfolobicins constitute a novel class of antimicrobial proteins without detectable homology to any other protein. 相似文献
78.
Linda E. Franken Fabrizia Fusetti Marc C. A. Stuart Egbert J. Boekema Oscar P. Kuipers Jan Kok Bert Poolman 《Molecular microbiology》2014,91(2):394-407
Dimerization and inactivation of ribosomes in Escherichia coli is a two‐step process that involves the binding of ribosome modulation factor (RMF) and hibernation promotion factor (HPF). Lactococcus lactis MG1363 expresses a protein, YfiALl, which associates with ribosomes in the stationary phase of growth and is responsible for dimerization of ribosomes. We show that full‐length YfiALl is necessary and sufficient for ribosome dimerization in L. lactis but also functions heterologously in vitro with E. coli ribosomes. Deletion of the yfiA gene has no effect on the growth rate but diminishes the survival of L. lactis under energy‐starving conditions. The N‐terminal domain of YfiALl is homologous to HPF from E. coli, whereas the C‐terminal domain has no counterpart in E. coli. By assembling ribosome dimers in vitro, we could dissect the roles of the N‐ and C‐terminal domains of YfiALl. It is concluded that the dimerization and inactivation of ribosomes in L. lactis and E. coli differ in several cellular and molecular aspects. In addition, two‐dimensional maps of dimeric ribosomes from L. lactis obtained by single particle electron microscopy show a marked structural difference in monomer association in comparison to the ribosome dimers in E. coli. 相似文献
79.
Fabrizia Caminiti Simona De Salvo Maria Cristina De Cola Margherita Russo Placido Bramanti Silvia Marino Rosella Ciurleo 《PloS one》2014,9(7)
Background
Several studies reported olfactory dysfunction in patients with multiple sclerosis. The estimate of the incidence of olfactory deficits in multiple sclerosis is uncertain; this may arise from different testing methods that may be influenced by patients'' response bias and clinical, demographic and cognitive features.Aims
To evaluate objectively the olfactory function using Olfactory Event Related Potentials.Materials and Methods
We tested the olfactory function of 30 patients with relapsing remitting multiple sclerosis (mean age of 36.03±6.96 years) and of 30 age, sex and smoking–habit matched healthy controls by using olfactory potentials. A selective and controlled stimulation of the olfactory system to elicit the olfactory event related potentials was achieved by a computer-controlled olfactometer linked directly with electroencephalograph. Relationships between olfactory potential results and patients'' clinical characteristics, such as gender, disability status score, disease-modifying therapy, and disease duration, were evaluated.Results
Seven of 30 patients did not show olfactory event related potentials. Sixteen of remaining 23 patients had a mean value of amplitude significantly lower than control group (p<0.01). The presence/absence of olfactory event related potentials was associated with dichotomous expanded disability status scale (p = 0.0433), as well as inversely correlated with the disease duration (r = −0.3641, p = 0.0479).Conclusion
Unbiased olfactory dysfunction of different severity found in multiple sclerosis patients suggests an organic impairment which could be related to neuroinflammatory and/or neurodegenerative processes of olfactory networks, supporting the recent findings on neurophysiopathology of disease. 相似文献80.
Iosief Abraha Fabiana Trotta Joseph M. Rimland Alfonso Cruz-Jentoft Isabel Lozano-Montoya Roy L. Soiza Valentina Pierini Paolo Dessì Fulgheri Fabrizia Lattanzio Denis O’Mahony Antonio Cherubini 《PloS one》2015,10(6)