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De novo assembly is a commonly used application of next-generation sequencing experiments. The ultimate goal is to puzzle millions of reads into one complete genome, although draft assemblies usually result in a number of gapped scaffold sequences. In this paper we propose an automated strategy, called GapFiller, to reliably close gaps within scaffolds using paired reads. The method shows good results on both bacterial and eukaryotic datasets, allowing only few errors. As a consequence, the amount of additional wetlab work needed to close a genome is drastically reduced. The software is available at http://www.baseclear.com/bioinformatics-tools/. 相似文献
74.
Natalello A Prokorov VV Tagliavini F Morbin M Forloni G Beeg M Manzoni C Colombo L Gobbi M Salmona M Doglia SM 《Journal of molecular biology》2008,381(5):1349-1361
The existence of several prion strains and their capacity of overcoming species barriers seem to point to a high conformational adaptability of the prion protein. To investigate this structural plasticity, we studied here the aggregation pathways of the human prion peptide PrP82-146, a major component of the Gerstmann-Sträussler-Scheinker amyloid disease.By Fourier transform infrared (FT-IR) spectroscopy, electron microscopy, and atomic force microscopy (AFM), we monitored the time course of PrP82-146 fibril formation. After incubation at 37 °C, the unfolded peptide was found to aggregate into oligomers characterized by intermolecular β-sheet infrared bands. At a critical oligomer concentration, the emergence of a new FT-IR band allowed to detect fibril formation. A different intermolecular β-sheet interaction of the peptides in oligomers and in fibrils is, therefore, detected by FT-IR spectroscopy, which, in addition, suggests a parallel orientation of the cross β-sheet structures of PrP82-146 fibrils. By AFM, a wide distribution of PrP82-146 oligomer volumes—the smallest ones containing from 5 to 30 peptides—was observed. Interestingly, the statistical analysis of AFM data enabled us to detect a quantization in the oligomer height values differing by steps of ∼ 0.5 nm that could reflect an orientation of oligomer β-strands parallel with the sample surface. Different morphologies were also detected for fibrils that displayed high heterogeneity in their twisting periodicity and a complex hierarchical assembly.Thermal aggregation of PrP82-146 was also investigated by FT-IR spectroscopy, which indicated for these aggregates an intermolecular β-sheet interaction different from that observed for oligomers and fibrils. Unexpectedly, random aggregates, induced by solvent evaporation, were found to display a significant α-helical structure as well as several β-sheet components.All these results clearly point to a high plasticity of the PrP82-146 peptide, which was found to be capable of undergoing several aggregation pathways, with end products displaying different secondary structures and intermolecular interactions. 相似文献
75.
Peptide mass fingerprinting (PMF) has over the years become one of the most commonly used tools for high-throughput analysis and identification of proteins. This method is applicable when relatively simple samples have to be analysed and it is commonly used for analysing proteins previously separated by 2-DE. The most common type of instrument used for this approach is the MALDI-TOF that has proved to be particularly suitable for the PMF analysis because of its characteristics of speed, robustness, sensitivity and automation. We have used a MALDI-TOF equipped with a novel parallel PSD capability (MALDI micro MX), to perform the analysis of two sets of different biological samples isolated by 2-DE. By using a method that integrates the data obtained by PMF analysis with the PSD data obtained in the same experiment, we show that the new multiplexed PSD solution increases the protein identification rate compared to the normal PMF approach. We also investigated the use of a charge-directed fragmentation modification reagent to improve the identification rate and confidence levels. 相似文献
76.
Marten H Hyun T Gomi K Seo S Hedrich R Roelfsema MR 《The Plant journal : for cell and molecular biology》2008,55(4):698-708
Light-induced stomatal opening in C3 and C4 plants is mediated by two signalling pathways. One pathway is specific for blue light and involves phototropins, while the second pathway depends on photosyntheticaly active radiation (PAR). Here, the role of Nt MPK4 in light-induced stomatal opening was studied, as silencing of this MAP kinase stimulates stomatal opening. Stomata of Nt MPK4-silenced plants do not close in elevated atmospheric CO2 , and show a reduced response to PAR. However, stomatal closure can still be induced by abscisic acid. Measurements using multi-barrelled intracellular micro-electrodes showed that CO2 activates plasma membrane anion channels in wild-type Nicotiana tabacum guard cells, but not in Nt MPK4-silenced cells. Anion channels were also activated in wild-type guard cells after switching off PAR. In approximately half of these cells, activation of anion channels was accompanied by an increase in the cytosolic free Ca2+ concentration. The activity of anion channels was higher in cells showing a parallel increase in cytosolic Ca2+ than in those with steady Ca2+ levels. Both the darkness-induced anion channel activation and Ca2+ signals were repressed in Nt MPK4-silenced guard cells. These data show that CO2 and darkness can activate anion channels in a Ca2+ -independent manner, but the anion channel activity is enhanced by parallel increases in the cytosolic Ca2+ concentration. Nt MPK4 plays an essential role in CO2 - and darkness-induced activation of guard-cell anion channels, through Ca2+ -independent as well as Ca2+ -dependent signalling pathways. 相似文献
77.
Vos MH Battistoni A Lechauve C Marden MC Kiger L Desbois A Pilet E de Rosny E Liebl U 《Biochemistry》2008,47(21):5718-5723
A survey is presented of picosecond kinetics of heme-residue bond formation after photolysis of histidine, methionine, or cysteine, in a broad range of ferrous six-coordinate heme proteins. These include human neuroglobin, a bacterial heme-binding superoxide dismutase (SOD), plant cytochrome b 559, the insect nuclear receptor E75, horse heart cytochrome c and the heme domain of the bacterial sensor protein Dos. We demonstrate that the fastest and dominant phase of binding of amino acid residues to domed heme invariably takes place with a time constant in the narrow range of 5-7 ps. Remarkably, this is also the case in the heme-binding SOD, where the heme is solvent-exposed. We reason that this fast phase corresponds to barrierless formation of the heme-residue bond from a configuration close to the bound state. Only in proteins where functional ligand exchange occurs, additional slower rebinding takes place on the time scale of tens of picoseconds after residue dissociation. We propose that the presence of these slower phases reflects flexibility in the heme environment that allows external ligands (O2, CO, NO, . . .) to functionally replace the internal residue after thermal dissociation of the heme-residue bond. 相似文献
78.
Jesper Stagegaard Marten Srensen Lars Peter Kvist 《Perspectives in Plant Ecology, Evolution and Systematics》2002,5(2):103
Extractions/applications of plant-resources were investigated in Mestizo communities in the Jenaro Herrera district, Peruvian Amazon. Knowledge differences between genders on forest resource uses were also examined. Two methods were applied: (1) a forest survey based on structured interviews of ten informants on potential uses of 334 pre-selected trees and lianas in permanent sample plots, and interviews of 20 male and female informants concerning potential uses of 85 trees and lianas; and (2) a household survey recording extracted materials in or near the dwellings of 73 families. The conclusions are: (i) most forest products are extracted from a limited number of species, whereas a large number of species is mentioned as important/potentially useful for identical purposes; (ii) coherence exists between extracted species and their abundance in easily accessible forest formations; (iii) knowledge of forest resources is gender correlated; and (iv) a combination of methods for collection of information on use and extraction of plant resources provides more detailed and profound results than using each method separately. 相似文献
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80.
Janna N. Vrijsen Indira Tendolkar Marten Onnink Martine Hoogman Aart H. Schene Guillén Fernández Iris van Oostrom Barbara Franke 《Attention deficit and hyperactivity disorders》2018,10(2):151-160
Stressful life events, especially Childhood Trauma, predict ADHD symptoms. Childhood Trauma and negatively biased memory are risk factors for affective disorders. The association of life events and bias with ADHD symptoms may inform about the etiology of ADHD. Memory bias was tested using a computer task in N = 675 healthy adults. Life events and ADHD symptoms were assessed using questionnaires. The mediation of the association between life events and ADHD symptoms by memory bias was examined. We explored the roles of different types of life events and of ADHD symptom clusters. Life events and memory bias were associated with overall ADHD symptoms as well as inattention and hyperactivity/impulsivity symptom clusters. Memory bias mediated the association of Lifetime Life Events, specifically Childhood Trauma, with ADHD symptoms. Negatively biased memory may be a cognitive marker of the effects of Childhood Trauma on the development and/or persistence of ADHD symptoms. 相似文献