975 resultados para Elicotteri, ibridi, ala fissa
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Complete mitochondrial genome plays an important role in the accurate revelation of phylogenetic relationships among metazoans. Here we present the complete mitochondrial genome sequence from a sea cucumber Apostichopus japonicus (Echinodermata: Holothuroidea), which is the first representative from the subclass Aspidochirotacea. The mitochondrial genome of A. japonicus is 16,096 bp in length. The heavy strand consists of 31.8% A, 20.2% C, 17.9% G, and 30.1% T bases (AT skew = 0.027: GC skew = 0.062). It contains thirteen protein-coding genes (PCGs), twenty-two transfer RNA genes, and two ribosomal RNA genes. There are a total of 3793 codons in all thirteen mitochondrial PCGs, excluding incomplete termination codons. The most frequently used amino acid is Leu (15.77%), followed by Set (9.73%), Met (8.62%), Phe (7.94%), and Ala (7.28%). Intergenetic regions in the mitochondrial genome of A. japonicus are 839 bp in total, with three relatively large regions of Unassigned Sequences (UAS) greater than 100 bp. The gene order of A. japonicus is identical to that observed in the five studied sea urchins, which confirms that the gene order shared by the two classes (Holothuroidea and Echinoidea) is a ground pattern of echinoderm mitochondrial genomes. Bayesian tree based on the cob gene supports the following relationship: (outgroup, (Crinoids, (Asteroids, Ophiuroids, (Echinoids, Holothuroids)))). (C) 2009 Elsevier B.V. All rights reserved.
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采用气相色谱- 质谱对采自云南白马雪山土壤中并经分离和发酵培养的被孢霉菌株SM96 的菌丝体油脂中脂肪酸组成进行了定性分析和峰面积相对含量测定, 共检测出30 种脂肪酸, 其中多不饱和脂肪酸含量为62. 4 % , 主要为亚油酸、α-亚麻酸(ALA) , 还有少量的γ- 亚麻酸、二十碳三烯酸、花生四烯酸和二十碳五烯酸( EPA) 等, 结果表明该菌株能产生EPA。
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近二十年生物化学,药理学,营养学的研究表明:多烯脂肪酸(PUFA)尤其是ω-3系列,具有特殊的生理功能。例如α-亚麻酸(α-Linolenic acid,ALA),EPA(Eicosapentaenoic aciod)具有降低血脂,预防心血管疾病发生的功效。而DHA(Docosahexaenoic acid)对大脑发育及视网膜的形成有着重要的促进作用^[1,2],自然界中,紫苏油中富含亚麻酸,鱼油中含有较多的EPA与DHA,将其富集提纯,可以提高产品的生理活性,成为目前保健品及医药开发的热点。
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Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers. Cross-selectivity was used to obtain simultaneous chiral separations of Cbz-DL-Ser and Cbz-DL-Ala by connecting two columns packed with Cbz-L-Ser and Cbz-L-Ala imprinted chiral stationary phase, respectively.
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28 hojas : ilustraciones.
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The initial phase in a content distribution (file sharing) scenario is a delicate phase due to the lack of global knowledge and the dynamics of the overlay. An unwise distribution of the pieces in this phase can cause delays in reaching steady state, thus increasing file download times. We devise a scheduling algorithm at the seed (source peer with full content), based on a proportional fair approach, and we implement it on a real file sharing client [1]. In dynamic overlays, our solution improves up to 25% the average downloading time of a standard protocol ala BitTorrent.
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Ataxia telangiectasia mutant (ATM) is an S/T-Q-directed kinase that is critical for the cellular response to double-stranded breaks (DSBs) in DNA. Following DNA damage, ATM is activated and recruited by the MRN protein complex [meiotic recombination 11 (Mre11)/DNA repair protein Rad50/Nijmegen breakage syndrome 1 proteins] to sites of DNA damage where ATM phosphorylates multiple substrates to trigger cell-cycle arrest. In cancer cells, this regulation may be faulty, and cell division may proceed even in the presence of damaged DNA. We show here that the ribosomal s6 kinase (Rsk), often elevated in cancers, can suppress DSB-induced ATM activation in both Xenopus egg extracts and human tumor cell lines. In analyzing each step in ATM activation, we have found that Rsk targets loading of MRN complex components onto DNA at DSB sites. Rsk can phosphorylate the Mre11 protein directly at S676 both in vitro and in intact cells and thereby can inhibit the binding of Mre11 to DNA with DSBs. Accordingly, mutation of S676 to Ala can reverse inhibition of the response to DSBs by Rsk. Collectively, these data point to Mre11 as an important locus of Rsk-mediated checkpoint inhibition acting upstream of ATM activation.
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To ensure genomic integrity, dividing cells implement multiple checkpoint pathways during the course of the cell cycle. In response to DNA damage, cells may either halt the progression of the cycle (cell cycle arrest) or undergo apoptosis. This choice depends on the extent of damage and the cell's capacity for DNA repair. Cell cycle arrest induced by double-stranded DNA breaks relies on the activation of the ataxia-telangiectasia (ATM) protein kinase, which phosphorylates cell cycle effectors (e.g., Chk2 and p53) to inhibit cell cycle progression. ATM is an S/T-Q directed kinase that is critical for the cellular response to double-stranded DNA breaks. Following DNA damage, ATM is activated and recruited to sites of DNA damage by the MRN protein complex (Mre11-Rad50-Nbs1 proteins) where ATM phosphorylates multiple substrates to trigger a cell cycle arrest. In cancer cells, this regulation may be faulty and cell division may proceed even in the presence of damaged DNA. We show here that the RSK kinase, often elevated in cancers, can suppress DSB-induced ATM activation in both Xenopus egg extracts and human tumor cell lines. In analyzing each step in ATM activation, we have found that RSK disrupts the binding of the MRN complex to DSB DNA. RSK can directly phosphorylate the Mre11 protein at Ser 676 both in vitro and in intact cells and can thereby inhibit loading of Mre11 onto DSB DNA. Accordingly, mutation of Ser 676 to Ala can reverse inhibition of the DSB response by RSK. Collectively, these data point to Mre11 as an important locus of RSK-mediated checkpoint inhibition acting upstream of ATM activation.
The phosphorylation of Mre11 on Ser 676 is antagonized by phosphatases. Here, we screened for phosphatases that target this site and identified PP5 as a candidate. This finding is consistent with the fact that PP5 is required for the ATM-mediated DNA damage response, indicating that PP5 may promote DSB-induced, ATM-dependent DNA damage response by targeting Mre11 upstream of ATM.
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In addition to antibodies, Th1-type T cell responses are also important for long-lasting protection against pertussis. However, upon immunization with the current acellular vaccines, many children fail to induce Th1-type responses, potentially due to immunomodulatory effects of some vaccine antigens, such as filamentous haemagglutinin (FHA). We therefore analysed the ability of FHA to modulate immune functions of human monocyte-derived dendritic cells (MDDC). FHA was purified from pertussis toxin (PTX)-deficient or from PTX- and adenylate cyclase-deficient Bordetella pertussis strains, and residual endotoxin was neutralized with polymyxin B. FHA from both strains induced phenotypic maturation of human MDDC and cytokine secretion (IL-10, IL-12p40, IL-12p70, IL-23 and IL-6). To identify the FHA domains responsible for MDDC immunomodulation, MDDC were stimulated with FHA containing a Gly→Ala substitution at its RGD site (FHA-RAD) or with an 80-kDa N-terminal moiety of FHA (Fha44), containing its heparin-binding site. Whereas FHA-RAD induced maturation and cytokine production comparable to those of FHA, Fha44 did not induce IL-10 production, but maturated MDDC at least partially. Nevertheless, Fha44 induced the secretion of IL-12p40, IL-12p70, IL-23 and IL-6 by MDDC, albeit at lower levels than FHA. Thus, FHA can modulate MDDC responses in multiple ways, and IL-10 induction can be dissociated from the induction of other cytokines.
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[This abstract is based on the authors' abstract.]Three new standards to be applied when adopting commercial computer off-the-shelf (COTS) software solutions are discussed. The first standard is for a COTS software life cycle, the second for a software solution user requirements life cycle, and the third is a checklist to help in completing the requirements. The standards are based on recent major COTS software solution implementations.
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The aim of this work is to improve retrieval and navigation services on bibliographic data held in digital libraries. This paper presents the design and implementation of OntoBib¸ an ontology-based bibliographic database system that adopts ontology-driven search in its retrieval. The presented work exemplifies how a digital library of bibliographic data can be managed using Semantic Web technologies and how utilizing the domain specific knowledge improves both search efficiency and navigation of web information and document retrieval.
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Los cambios sufridos por los modelos de comunicación científica hacen que las bibliotecas universitarias se vean obligadas a dar nuevos servicios. Para adecuarse al investigador los bibliotecarios están desarrollando habilidades, colaborando con cada vez más estamentos y sustentando el acceso abierto. Apoyándose en una lista de posibles servicios, basada en la literatura especializada, este trabajo pretende cuantificar y evaluar el apoyo a la investigación desde las bibliotecas universitarias españolas. El sondeo demuestra la aparición de nuevos servicios e infraestructuras. Pero estas asistencias no suelen sistematizarse, difundirse ni evaluarse. Y, por otra parte, las consecuentes inversiones en personal y TIC han generado una brecha entre universidades
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Aminolevulinic acid (ALA) stability within topical formulations intended for photodynamic therapy (PDT) is poor due to dimerisation to pyrazine-2,5-dipropionic acid (PY). Most strategies to improve stability use low pH vehicles, which can cause cutaneous irritancy. To overcome this problem, a novel approach is investigated that uses a non-aqueous vehicle to retard proton-induced charge separation across the 4-carbonyl group on ALA and lessen nucleophilic attack that leads to condensation dimerisation. Bioadhesive anhydrous vehicles based on methylvinylether-maleic anhydride copolymer patches and poly(ethyleneglycol) or glycerol thickened poly(acrylic acid) gels were formulated. ALA stability fell below pharmaceutically acceptable levels after 6 months, with bioadhesive patches stored at 5°C demonstrating the best stability by maintaining 86.2% of their original loading. Glycerol-based gels maintained 40.2% in similar conditions. However, ALA loss did not correspond to expected increases in PY, indicating the presence of another degradative process that prevented dimerisation. Nuclear magnetic resonance (NMR) analysis was inconclusive in respect of the mechanism observed in the patch system, but showed clearly that an esterification reaction involving ALA and both glycerol and poly(ethyleneglycol) was occurring. This was especially marked in the glycerol gels, where only 2.21% of the total expected PY was detected after 204 days at 5°C. Non-specific esterase hydrolysis demonstrated that ALA was recoverable from the gel systems, further supporting esterified binding within the gel matrices. It is conceivable that skin esterases could duplicate this finding upon topical application of the gel and convert these derivatives back to ALA in situ, provided skin penetration is not affected adversely.