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排序方式: 共有164条查询结果,搜索用时 15 毫秒
1.
Abstract A cryptic plasmid, pUCL287, was isolated from Tetragenococcus halophila (Pediococcus halophilus) ATCC 33315. It had a theta-type mechanism of replication in its natural host. Its minimal replicon, Rep 281, was isolated on a 1.6-kb Eco RI fragment. The Rep 287 host range included the genera Pediococcus, Enterococcus, Lactobacillus and Leuconostoc but not genus Lactococcus . Plasmids hybridizing to pUCL287 are rare among lactic acid bacteria. As assessed by hybridization, Rep2Sl is dissimilar to pAMβ1, pIP50l and pUCL22, representatives of the most common theta-type replicon groups in Gram-positive bacteria. Therefore, pUCL287 appears to represent a new theta-type replicon family from lactic acid bacteria. 相似文献
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Luc Demange Fatma Nait Abdellah Olivier Lozach Yoan Ferandin Nohad Gresh Laurent Meijer Hervé Galons 《Bioorganic & medicinal chemistry letters》2013,23(1):125-131
Cyclin dependent kinase 5 (CDK5) is a serine/threonine kinase belonging to the cyclin dependent kinase (CDK) family. CDK5 is involved in numerous neuronal diseases (including Alzheimer’s or Parkinson’s diseases, stroke, traumatic brain injury), pain signaling and cell migration. In the present Letter, we describe syntheses and biological evaluations of new 2,6,9-trisubstituted purines, structurally related to roscovitine, a promising CDK inhibitor currently in clinical trials (CDK1/Cyclin B, IC50 = 350 nM; CDK5/p25, IC50 = 200 nM). These new molecules were synthesized using an original Buchwald–Hartwig catalytic procedure; several compounds (3j, 3k, 3l, 3e, 4k, 6b, 6c) displayed potent kinase inhibitory potencies against CDK5 (IC50 values ranging from 17 to 50 nM) and showed significant cell death inducing activities (IC50 values ranging from 2 to 9 μM on SH-SY5Y). The docking of the inhibitors into the ATP binding domain of the CDK5 catalytic site highlighted the discriminatory effect of a hydrogen bond involving the CDK5 Lys-89. In addition, the calculated final energy balances for complexation measured for several inhibitors is consistent with the ranking of the IC50 values. Lastly, we observed that several compounds exhibit submicromolar activities against DYRK1A (dual specificity, tyrosine phosphorylation regulated kinase 1A), a kinase involved in Down syndrome and Alzheimer’s disease (3g, 3h, 4m; IC50 values ranging from 300 to 400 nM). 相似文献
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The liassic beds of the High-Atlas of Marrakech are rarely fossiliferous so all paleontological discoveries must be reported in order to give more biostratigraphical precisions for the interpretations of the sourcestrata basin. Palynological investigations in section composed of marl and dolomites with gypsum yield assemblages which the overall composition is characterized by the general dominance of Corollina in combination with relatively rare occurence of others nonsaccate pollen grains. Because the comparison of the associations previously described from the Lower Jurassic of Morocco and Sahara and the fact that the richness of Corollina has no stratigraphical value, the assemblages from the Telouat' section can be reasonably regarded to be indicative of a Sinemurian age. 相似文献
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Abdellah Barakate James D. Higgins Sebastian Vivera Jennifer Stephens Ruth M. Perry Luke Ramsay Isabelle Colas Helena Oakey Robbie Waugh F. Chris H. Franklin Susan J. Armstrong Claire Halpin 《The Plant cell》2014,26(2):729-740
In many cereal crops, meiotic crossovers predominantly occur toward the ends of
chromosomes and 30 to 50% of genes rarely recombine. This limits the exploitation of
genetic variation by plant breeding. Previous reports demonstrate that chiasma
frequency can be manipulated in plants by depletion of the synaptonemal complex
protein ZIPPER1 (ZYP1) but conflict as to the direction of change, with fewer
chiasmata reported in Arabidopsis thaliana and more crossovers
reported for rice (Oryza sativa). Here, we use RNA interference
(RNAi) to reduce the amount of ZYP1 in
barley (Hordeum vulgare) to only 2 to 17% of normal zygotene levels.
In the ZYP1RNAi lines, fewer than half of the chromosome
pairs formed bivalents at metaphase and many univalents were observed, leading to
chromosome nondisjunction and semisterility. The number of chiasmata per cell was
reduced from 14 in control plants to three to four in the ZYP1-depleted lines,
although the localization of residual chiasmata was not affected. DNA double-strand
break formation appeared normal, but the recombination pathway was defective at later
stages. A meiotic time course revealed a 12-h delay in prophase I progression to the
first labeled tetrads. Barley ZYP1 appears to function similarly to ZIP1/ZYP1 in
yeast and Arabidopsis, with an opposite effect on crossover number
to ZEP1 in rice, another member of the Poaceae. 相似文献
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Felipe Romero-Saavedra Diana Laverde Dominique Wobser Charlotte Michaux Aurélie Budin-Verneuil Benoit Bernay Abdellah Benachour Axel Hartke Johannes Huebner 《PloS one》2014,9(11)
Infections by opportunistic bacteria have significant contributions to morbidity and mortality of hospitalized patients and also lead to high expenses in healthcare. In this setting, one of the major clinical problems is caused by Gram-positive bacteria such as enterococci and staphylococci. In this study we extract, purify, identify and characterize immunogenic surface-exposed proteins present in the vancomycin resistant enterococci (VRE) strain Enterococcus faecium E155 using three different extraction methods: trypsin shaving, biotinylation and elution at high pH. Proteomic profiling was carried out by gel-free and gel-nanoLC-MS/MS analyses. The total proteins found with each method were 390 by the trypsin shaving, 329 by the elution at high pH, and 45 using biotinylation. An exclusively extracytoplasmic localization was predicted in 39 (10%) by trypsin shaving, in 47 (15%) by elution at high pH, and 27 (63%) by biotinylation. Comparison between the three extraction methods by Venn diagram and subcellular localization predictors (CELLO v.2.5 and Gpos-mPLoc) allowed us to identify six proteins that are most likely surface-exposed: the SCP-like extracellular protein, a low affinity penicillin-binding protein 5 (PBP5), a basic membrane lipoprotein, a peptidoglycan-binding protein LysM (LysM), a D-alanyl-D-alanine carboxypeptidase (DdcP) and the peptidyl-prolyl cis-trans isomerase (PpiC). Due to their close relationship with the peptidoglycan, we chose PBP5, LysM, DdcP and PpiC to test their potential as vaccine candidates. These putative surface-exposed proteins were overexpressed in Escherichia coli and purified. Rabbit polyclonal antibodies raised against the purified proteins were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Passive immunization with rabbit antibodies raised against these proteins reduced significantly the colony counts of E. faecium E155 in mice, indicating the effectiveness of these surface-related proteins as promising vaccine candidates to target different enterococcal pathogens. 相似文献
8.
Hicham Ben Alla Said Ben Alla Abdellah Touhafi Abdellah Ezzati 《Cluster computing》2018,21(4):1797-1820
Task scheduling is one of the most challenging aspects to improve the overall performance of cloud computing and optimize cloud utilization and Quality of Service (QoS). This paper focuses on Task Scheduling optimization using a novel approach based on Dynamic dispatch Queues (TSDQ) and hybrid meta-heuristic algorithms. We propose two hybrid meta-heuristic algorithms, the first one using Fuzzy Logic with Particle Swarm Optimization algorithm (TSDQ-FLPSO), the second one using Simulated Annealing with Particle Swarm Optimization algorithm (TSDQ-SAPSO). Several experiments have been carried out based on an open source simulator (CloudSim) using synthetic and real data sets from real systems. The experimental results demonstrate the effectiveness of the proposed approach and the optimal results is provided using TSDQ-FLPSO compared to TSDQ-SAPSO and other existing scheduling algorithms especially in a high dimensional problem. The TSDQ-FLPSO algorithm shows a great advantage in terms of waiting time, queue length, makespan, cost, resource utilization, degree of imbalance, and load balancing. 相似文献
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Raboisson P Lin TI Kock Hd Vendeville S Vreken WV McGowan D Tahri A Hu L Lenz O Delouvroy F Surleraux D Wigerinck P Nilsson M Rosenquist S Samuelsson B Simmen K 《Bioorganic & medicinal chemistry letters》2008,18(18):5095-5100
Starting from the previously reported HCV NS3/4A protease inhibitor BILN 2061, we have used a fast-follower approach to identify a novel series of HCV NS3/4A protease inhibitors in which (i) the P3 amino moiety and its capping group have been truncated, (ii) a sulfonamide is introduced in the P1 cyclopropyl amino acid, (iii) the position 8 of the quinoline is substituted with a methyl or halo group, and (iv) the ring size of the macrocycle has been reduced to 14 atoms. SAR analysis performed with a limited set of compounds led to the identification of N-{17-[8-chloro-2-(4-isopropylthiazol-2-yl)-7-methoxyquinolin-4-yloxy]-2,14-dioxo-3,15-diazatricyclo [13.3.0.0 [Bartenschlager, R.; Lohmann, V. J. Gen. Virol. 2000, 81, 1631; Vincent Soriano, Antonio Madejon, Eugenia Vispo, Pablo Labarga, Javier Garcia-Samaniego, Luz Martin-Carbonero, Julie Sheldon, Marcelle Bottecchia, Paula Tuma, Pablo Barreiro Expert Opin. Emerg. Drugs, 2008, 13, 1-19]]octadec-7-ene-4-carbonyl}(1-methylcyclopropyl)(1-methylcyclopropyl)sulfonamide 19l an extremely potent (K(i)=0.20 nM, EC(50)=3.7 nM), selective, and orally bioavailable dipeptide NS3/4A protease inhibitor, which has features attractive for further preclinical development. 相似文献