995 resultados para DOMAIN TRANSFER


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Pseudomonas protegens is a biocontrol rhizobacterium with a plant-beneficial and an insect pathogenic lifestyle, but it is not understood how the organism switches between the two states. Here, we focus on understanding the function and possible evolution of a molecular sensor that enables P. protegens to detect the insect environment and produce a potent insecticidal toxin specifically during insect infection but not on roots. By using quantitative single cell microscopy and mutant analysis, we provide evidence that the sensor histidine kinase FitF is a key regulator of insecticidal toxin production. Our experimental data and bioinformatic analyses indicate that FitF shares a sensing domain with DctB, a histidine kinase regulating carbon uptake in Proteobacteria. This suggested that FitF has acquired its specificity through domain shuffling from a common ancestor. We constructed a chimeric DctB-FitF protein and showed that it is indeed functional in regulating toxin expression in P. protegens. The shuffling event and subsequent adaptive modifications of the recruited sensor domain were critical for the microorganism to express its potent insect toxin in the observed host-specific manner. Inhibition of the FitF sensor during root colonization could explain the mechanism by which P. protegens differentiates between the plant and insect host. Our study establishes FitF of P. protegens as a prime model for molecular evolution of sensor proteins and bacterial pathogenicity.

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This study examines how MPEG-2 Transport Stream, used in DVB-T video transmission, can be reliably and efficiently transferred to remote locations over an MPLS network. All the relevant technologies used in this scenario are also discussed in the study. This study was done for Digita Oy, which is a major radio and television content distributor in Finland. The theoretical part of the study begins with the introduction to MPLS technology and continues with explanation of IP Multicast and its components. The fourth section discusses MPEG-2 and the formation and content of MPEG-2 Transport Stream. These technologies were studied in relevant literature and RFC documentation. After the theoretical part of the study, the test setup and the test cases are presented. The results of the test cases, and the conclusions that can be drawn based on them, are discussed in the last section of the study. The tests showed that it is possible to transfer digital video quite reliably over an MPLS network using IP Multicast. By configuring the equipment correctly, the recovery time of the network in case of a failure can be shortened remarkably. Also, the unwanted effect of other traffic on the critical video traffic can be eliminated by defining the Quality of Service parameters correctly. There are, however, some issues that need to be tested further before this setup can be used in broadcast networks. Reliable operation of IP Multicast and proper error correction are the main subjects for future testing.

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Pyrimethamine is used as and anti-infectious agent because of its antifolate properties. Its action is synergistic with that of dapsone and sulfamides on Toxoplasma gondii. The goal of the present study was to evaluate the placental transfer of pyrimethamine in an ex vivo model of perfused human placental cotyledon at term. Human placentas were perfused according to the slightly modified method of Schneider. The pyrimethamine fetal transfer rate was approximately 30%, while cotyledon clearance was about 1.8 ml/min. The placental transfer of pyrimethamine seems to be independent of the maternal concentrations of pyrimethamine, suggesting passive diffusion mechanisms or a nonsaturable active transport at the tested concentrations.

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El tema de este estudio es el aumento de la comprensión teórica y empírica de la estrategia de negocio de código abierto en el dominio de sistemas embebidos por investigar modelos de negocios de código abierto, retos, recursos y capacidades operativas y dinámicas.

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Mutations in the fibroblast growth factor receptor 2 (FGFR2) cause a variety of craniosynostosis syndromes. The mutational spectrum tends to be narrow with the majority of mutations occurring in either exon IIIa or IIIc or in the intronic sequence preceding exon IIIc. Mutations outside of this hotspot are uncommon and the few identified mutations have demonstrated wide clinical variability, making it difficult to establish a clear-cut genotype-phenotype correlation. To better delineate the clinical picture associated with these unusual mutations, we describe a severely affected patient with Pfeiffer syndrome and a missense mutation in the tyrosine kinase (TK) domain of FGFR2.

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Objective Analyzing the policy transfer of directly observed treatment of tuberculosis from the perspective of nursing. Method This is a descriptive study with qualitative approach, which had 10 nurses of the Family Health Strategy in São Paulo as subjects. The interviews were carried out between May and June 2013, and were adopted the technique of thematic content analysis and the referential of policy transfer. Results On the signification of this treatment, are related the senses of disciplinary monitoring, the bond and approximation to the context of patients’ lives. Operationally, nurses, community health agents and nursing technicians stand out as agents of implementation of this policy, developing multiple actions of user embracement. The nurse is evidenced as an educator in health, leader in the family health team, and capable of creating emotional bond with users. Conclusion It was found that the innovations proposed in the treatment are incipient in the daily work of nurses.

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The family of death domain (DD)-containing proteins are involved in many cellular processes, including apoptosis, inflammation and development. One of these molecules, the adapter protein MyD88, is a key factor in innate and adaptive immunity that integrates signals from the Toll-like receptor/interleukin (IL)-1 receptor (TLR/IL-1R) superfamily by providing an activation platform for IL-1R-associated kinases (IRAKs). Here we show that the DD-containing protein Unc5CL (also known as ZUD) is involved in a novel MyD88-independent mode of IRAK signaling that culminates in the activation of the transcription factor nuclear factor kappa B (NF-κB) and c-Jun N-terminal kinase. Unc5CL required IRAK1, IRAK4 and TNF receptor-associated factor 6 but not MyD88 for its ability to activate these pathways. Interestingly, the protein is constitutively autoproteolytically processed, and is anchored by its N-terminus specifically to the apical face of mucosal epithelial cells. Transcriptional profiling identified mainly chemokines, including IL-8, CXCL1 and CCL20 as Unc5CL target genes. Its prominent expression in mucosal tissues, as well as its ability to induce a pro-inflammatory program in cells, suggests that Unc5CL is a factor in epithelial inflammation and immunity as well as a candidate gene involved in mucosal diseases such as inflammatory bowel disease.

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Vibrio vulnificus and Vibrio cholerae are Gram-negative pathogens that cause serious infectious disease in humans. The beta form of pro-IL-1 is thought to be involved in inflammatory responses and disease development during infection with these pathogens, but the mechanism of beta form of pro-IL-1 production remains poorly defined. In this study, we demonstrate that infection of mouse macrophages with two pathogenic Vibrio triggers the activation of caspase-1 via the NLRP3 inflammasome. Activation of the NLRP3 inflammasome was mediated by hemolysins and multifunctional repeat-in-toxins produced by the pathogenic bacteria. NLRP3 activation in response to V. vulnificus infection required NF-kappaB activation, which was mediated via TLR signaling. V. cholerae-induced NLRP3 activation also required NF-kappaB activation but was independent of TLR stimulation. Studies with purified V. cholerae hemolysin revealed that toxin-stimulated NLRP3 activation was induced by TLR and nucleotide-binding oligomerization domain 1/2 ligand-mediated NF-kappaB activation. Our results identify the NLRP3 inflammasome as a sensor of Vibrio infections through the action of bacterial cytotoxins and differential activation of innate signaling pathways acting upstream of NF-kappaB.

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A previously developed high performance liquid chromatography mass spectrometry (HPLC-MS) procedure for the simultaneous determination of antidementia drugs, including donepezil, galantamine, memantine, rivastigmine and its metabolite NAP 226-90, was transferred to an ultra performance liquid chromatography system coupled to a tandem mass spectrometer (UPLC-MS/MS). The drugs and their internal standards ([(2)H(7)]-donepezil, [(13)C,(2)H(3)]-galantamine, [(13)C(2),(2)H(6)]-memantine, [(2)H(6)]-rivastigmine) were extracted from 250μL human plasma by protein precipitation with acetonitrile. Chromatographic separation was achieved on a reverse phase column (BEH C18 2.1mm×50mm; 1.7μm) with a gradient elution of an ammonium acetate buffer at pH 9.3 and acetonitrile at a flow rate of 0.4mL/min and an overall run time of 4.5min. The analytes were detected on a tandem quadrupole mass spectrometer operated in positive electrospray ionization mode, and quantification was performed using multiple reaction monitoring. The method was validated according to the recommendations of international guidelines over a calibration range of 1-300ng/mL for donepezil, galantamine and memantine, and 0.2-50ng/mL for rivastimgine and NAP 226-90. The trueness (86-108%), repeatability (0.8-8.3%), intermediate precision (2.3-10.9%) and selectivity of the method were found to be satisfactory. Matrix effects variability was inferior to 15% for the analytes and inferior to 5% after correction by internal standards. A method comparison was performed with patients' samples showing similar results between the HPLC-MS and UPLC-MS/MS procedures. Thus, this validated UPLC-MS/MS method allows to reduce the required amount of plasma, to use a simplified sample preparation, and to obtain a higher sensitivity and specificity with a much shortened run-time.

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Spondyloepimetaphyseal dysplasia with joint laxity, leptodactylic type (lepto-SEMDJL, aka SEMDJL, Hall type), is an autosomal dominant skeletal disorder that, in spite of being relatively common among skeletal dysplasias, has eluded molecular elucidation so far. We used whole-exome sequencing of five unrelated individuals with lepto-SEMDJL to identify mutations in KIF22 as the cause of this skeletal condition. Missense mutations affecting one of two adjacent amino acids in the motor domain of KIF22 were present in 20 familial cases from eight families and in 12 other sporadic cases. The skeletal and connective tissue phenotype produced by these specific mutations point to functions of KIF22 beyond those previously ascribed functions involving chromosome segregation. Although we have found Kif22 to be strongly upregulated at the growth plate, the precise pathogenetic mechanisms remain to be elucidated.

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MHC class II-peptide multimers are important tools for the detection, enumeration and isolation of antigen-specific CD4+ Τ cells. However, their erratic and often poor performance impeded their broad application and thus in-depth analysis of key aspects of antigen-specific CD4+ Τ cell responses. In the first part of this thesis we demonstrate that a major cause for poor MHC class II tetramer staining performance is incomplete peptide loading on MHC molecules. We observed that peptide binding affinity for "empty" MHC class II molecules poorly correlates with peptide loading efficacy. Addition of a His-tag or desthiobiotin (DTB) at the peptide N-terminus allowed us to isolate "immunopure" MHC class II-peptide monomers by affinity chromatography; this significantly, often dramatically, improved tetramer staining of antigen-specific CD4+ Τ cells. Insertion of a photosensitive amino acid between the tag and the peptide, permitted removal of the tag from "immunopure" MHC class II-peptide complex by UV irradiation, and hence elimination of its potential interference with TCR and/or MHC binding. Moreover, to improve loading of self and tumor antigen- derived peptides onto "empty" MHC II molecules, we first loaded these with a photocleavable variant of the influenza A hemagglutinin peptide HA306-318 and subsequently exchanged it with a poorly loading peptide (e.g. NY-ESO-1119-143) upon photolysis of the conditional ligand. Finally, we established a novel type of MHC class II multimers built on reversible chelate formation between 2xHis-tagged MHC molecules and a fluorescent nitrilotriacetic acid (NTA)-containing scaffold. Staining of antigen-specific CD4+ Τ cells with "NTAmers" is fully reversible and allows gentle cell sorting. In the second part of the thesis we investigated the role of the CD8α transmembrane domain (TMD) for CD8 coreceptor function. The sequence of the CD8α TMD, but not the CD8β TMD, is highly conserved and homodimerizes efficiently. We replaced the CD8α TMD with the one of the interleukin-2 receptor a chain (CD8αTac) and thus ablated CD8α TMD interactions. We observed that ΤΙ Τ cell hybridomas expressing CD8αTacβ exhibited severely impaired intracellular calcium flux, IL-2 responses and Kd/PbCS(ABA) P255A tetramer binding. By means of fluorescence resonance energy transfer experiments (FRET) we established that CD8αTacβ associated with TCR:CD3 considerably less efficiently than CD8αβ, both in the presence and the absence of Kd/PbCS(ABA) complexes. Moreover, we observed that CD8αTacβ partitioned substantially less in lipid rafts, and related to this, associated less efficiently with p56Lck (Lck), a Src kinase that plays key roles in TCR proximal signaling. Our results support the view that the CD8α TMD promotes the formation of CD8αβP-CD8αβ dimers on cell surfaces. Because these contain two CD8β chains and that CD8β, unlike CD8α, mediates association of CD8 with TCR:CD3 as well as with lipid rafts and hence with Lck, we propose that the CD8αTMD plays an important and hitherto unrecognized role for CD8 coreceptor function, namely by promoting CD8αβ dimer formation. We discuss what implications this might have on TCR oligomerization and TCR signaling. - Les multimères de complexes MHC classe II-peptide sont des outils importants pour la détection, le dénombrement et l'isolation des cellules Τ CD4+ spécifiques pour un antigène d'intérêt. Cependant, leur performance erratique et souvent inadéquate a empêché leur utilisation généralisée, limitant ainsi l'analyse des aspects clés des réponses des lymphocytes Τ CD4+. Dans la première partie de cette thèse, nous montrons que la cause principale de la faible efficacité des multimères de complexes MHC classe II-peptide est le chargement incomplet des molécules MHC par des peptides. Nous montrons également que l'affinité du peptide pour la molécule MHC classe II "vide" n'est pas nécessairement liée au degré du chargement. Grâce à l'introduction d'une étiquette d'histidines (His-tag) ou d'une molécule de desthiobiotine à l'extrémité N-terminale du peptide, des monomères MHC classe II- peptide dits "immunopures" ont pu être isolés par chromatographic d'affinité. Ceci a permis d'améliorer significativement et souvent de façon spectaculaire, le marquage des cellules Τ CD4+ spécifiques pour un antigène d'intérêt. L'insertion d'un acide aminé photosensible entre l'étiquette et le peptide a permis la suppression de l'étiquette du complexe MHC classe- Il peptide "immunopure" par irradiation aux UV, éliminant ainsi de potentielles interférences de liaison au TCR et/ou au MHC. De plus, afin d'améliorer le chargement des molécules MHC classe II "vides" avec des peptides dérivés d'auto-antigènes ou d'antigènes tumoraux, nous avons tout d'abord chargé les molécules MHC "vides" avec un analogue peptidique photoclivable issu du peptide HA306-318 de l'hémagglutinine de la grippe de type A, puis, sous condition de photolyse, nous l'avons échangé avec de peptides à chargement faible (p.ex. NY-ESO-1119-143). Finalement, nous avons construit un nouveau type de multimère réversible, appelé "NTAmère", basé sur la formation chélatante reversible entre les molécules MHC-peptide étiquettés par 2xHis et un support fluorescent contenant des acides nitrilotriacetiques (NTA). Le marquage des cellules Τ CD4+ spécifiques pour un antigène d'intérêt avec les "NTAmères" est pleinement réversible et permet également un tri cellulaire plus doux. Dans la deuxième partie de cette thèse nous avons étudié le rôle du domaine transmembranaire (TMD) du CD8α pour la fonction coréceptrice du CD8. La séquence du TMD du CD8α, mais pas celle du TMD du CD8β, est hautement conservée et permet une homodimérisation efficace. Nous avons remplacé le TMD du CD8α avec celui de la chaîne α du récepteur à l'IL-2 (CD8αTac), éliminant ainsi les interactions du TMD du CD8α. Nous avons montré que les cellules des hybridomes Τ T1 exprimant le CD8αTacβ présentaient une atteinte sévère du flux du calcium intracellulaire, des réponses d'IL-2 et de la liaison des tétramères Kd/PbCS(ABA) P255A. Grâce aux expériences de transfert d'énergie entre molécules fluorescentes (FRET), nous avons montré que l'association du CD8αTacβ avec le TCR:CD3 est considérablement moins efficace qu'avec le CD8αβ, et ceci aussi bien en présence qu'en absence de complexes Kd/PbCS(ABA). De plus, nous avons observé que le CD8αTacβ se distribuait beaucoup moins bien dans les radeaux lipidiques, engendrant ainsi, une association moins efficace avec p56Lck (Lck), une kinase de la famille Src qui joue un rôle clé dans la signalisation proximale du TCR. Nos résultats soutiennent l'hypothèse que le TMD du CD8αβ favorise la formation des dimères de CD8αβ à la surface des cellules. Parce que ces derniers contiennent deux chaînes CD8β et que CD8β, contrairement à CD8α, favorise l'association du CD8 au TCR:CD3 aussi bien qu'aux radeaux lipidiques et par conséquent à Lck, nous proposons que le TMD du CD8α joue un rôle important, jusqu'alors inconnu, pour la fonction coreceptrice du CD8, en encourageant la formation des dimères CD8αβ. Nous discutons des implications possibles sur l'oligomerisation du TCR et la signalisation du TCR.

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BACKGROUND: Human immunodeficiency virus (HIV) takes advantage of multiple host proteins to support its own replication. The gene ZNRD1 (zinc ribbon domain-containing 1) has been identified as encoding a potential host factor that influenced disease progression in HIV-positive individuals in a genomewide association study and also significantly affected HIV replication in a large-scale in vitro short interfering RNA (siRNA) screen. Genes and polymorphisms identified by large-scale analysis need to be followed up by means of functional assays and resequencing efforts to more precisely map causal genes. METHODS: Genotyping and ZNRD1 gene resequencing for 208 HIV-positive subjects (119 who experienced long-term nonprogression [LTNP] and 89 who experienced normal disease progression) was done by either TaqMan genotyping assays or direct sequencing. Genetic association analysis was performed with the SNPassoc package and Haploview software. siRNA and short hairpin RNA (shRNA) specifically targeting ZNRD1 were used to transiently or stably down-regulate ZNRD1 expression in both lymphoid and nonlymphoid cells. Cells were infected with X4 and R5 HIV strains, and efficiency of infection was assessed by reporter gene assay or p24 assay. RESULTS: Genetic association analysis found a strong statistically significant correlation with the LTNP phenotype (single-nucleotide polymorphism rs1048412; [Formula: see text]), independently of HLA-A10 influence. siRNA-based functional analysis showed that ZNRD1 down-regulation by siRNA or shRNA impaired HIV-1 replication at the transcription level in both lymphoid and nonlymphoid cells. CONCLUSION: Genetic association analysis unequivocally identified ZNRD1 as an independent marker of LTNP to AIDS. Moreover, in vitro experiments pointed to viral transcription as the inhibited step. Thus, our data strongly suggest that ZNRD1 is a host cellular factor that influences HIV-1 replication and disease progression in HIV-positive individuals.

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Integrative and conjugating elements (ICE) are self-transferable DNAs widely present in bacterial genomes, which often carry a variety of auxiliary genes of potential adaptive benefit. One of the model ICE is ICEclc, an element originally found in Pseudomonas knackmussii B13 and known for its propensity to provide its host with the capacity to metabolize chlorocatechols and 2-aminophenol. In this work, we studied the mechanism and target of regulation of MfsR, a TetR-type repressor previously found to exert global control on ICEclc horizontal transfer. By using a combination of ICEclc mutant and transcriptome analysis, gene reporter fusions, and DNA binding assays, we found that MfsR is a repressor of both its own expression and that of a gene cluster putatively coding for a major facilitator superfamily efflux system on ICEclc (named mfsABC). Phylogenetic analysis suggests that mfsR was originally located immediately adjacent to the efflux pump genes but became displaced from its original cis target DNA by a gene insertion. This resulted in divergence of the original bidirectional promoters into two separated individual regulatory units. Deletion of mfsABC did not result in a strong phenotype, and despite screening a large number of compounds and conditions, we were unable to define the precise current function or target of the putative efflux pump. Our data reconstruct how the separation of an ancestor mfsR-mfsABC system led to global control of ICEclc transfer by MfsR.

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Lamprophyre dykes have been recently discovered in blocks of gneiss embedded in a calcschist formation of wildflysch type that forms the top of the Mesozoic-Tertiary metasedimentary cover of the Antigorio nappe (the Teggiolo zone) in the Val Bavona (Lower Penninic, NW Ticino, Switzerland). The presence of the lamprophyres gives a clue to the possible source of these blocks. Similar dykes occur in the N part of the Maggia nappe where they are intruded into the Matorello granite and the surrounding gneisses. We studied these lamprophyres at two localities in the Teggiolo zone (Tamierpass and Lago del Zott) and at one locality in the Maggia nappe (Laghetti). Detailed mineralogical and geochemical investigations confirm their great similarity, particularly between the Tamier and Laghetti dykes. They all recrystallized during Alpine metamorphism under amphibolite facies conditions and lost their primary mineral assemblages and textures. The chemistry reveals a calc-alkaline affinity, a limited differentiation range, features of mineral accumulation and intense remobilization in some cases. The lamprophyres are characterized by a high mg# and relatively low contents in REE and other incompatible elements. In situ SHRIMP and LA-ICPMS U-Pb zircon dating yielded ages of 284.8 +/- 1.7 Ma (Tamier), 290.0 +/- 1.3 Ma (Zott) and 290.5 +/- 3.7 Ma (Laghetti). These ages are compatible with the general late- to post-Variscan magmatic evolution of the Helvetic and Lower Penninic domains. The lamprophyres are considered as melts derived from the lithospheric Variscan mantle, variously hybridized and differentiated at the contact with crustal material during late- to post-orogenic extension. These lamprophyres are chemically distinct from earlier lamprophyres of Visean age, emplaced together with their associated granites in transcurrent fault zones during the Variscan orogenic compression. The similarity of these different dykes suggests that the front of the Maggia nappe is a likely source of the gneissic blocks embedded in the calcschists at the top of the Teggiolo zone. They would have been provided by the advancing Maggia nappe during its thrusting over the Antigorio nappe and simultaneous closure of the Teggiolo sedimentary basin.