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High-throughput strategies for molecular diagnosis of nonsyndromic inherited retinal dystrophiesRodríguez Muñoz, Ana 20 March 2020 (has links)
[ES] Las distrofias hereditarias de la retina (DHR) son un conjunto de trastornos caracterizados por la muerte, generalmente, progresiva de fotorreceptores y células del epitelio pigmentario retiniano. Las DHR afectan a más de 2 millones de personas en el mundo, produciendo una pérdida parcial y, en muchos casos, total de la visión, para la cual no existe ningún tratamiento que revierta o frene la progresión de la enfermedad. Se caracterizan por una elevada heterogeneidad clínica y genética, identificándose hasta la fecha mutaciones en más de 250 genes responsable de algún tipo de DHR.
Esta tesis doctoral se ha centrado en el diagnóstico genético de 208 pacientes afectados de DHR no sindrómica (DHR-NS), mediante secuenciación masiva dirigida a un panel de 117 genes y cinco regiones intrónicas profundas en las que previamente se habían descrito mutaciones. Las variantes identificadas en los pacientes se priorizaron de acuerdo a la mínima frecuencia alélica y se clasificaron según los criterios de la guía del American College of Medical Genetics and Genomics. Las variantes de número de copias identificadas mediante la secuenciación del panel se validaron utilizando multiplex ligation-dependent probe amplification o array genómico. A todos los pacientes se les realizó un estudio oftalmológico, más o menos exhaustivo, incluyendo pruebas electrofisiológicas. Además, se realizaron ensayos in vitro con minigenes para comprobar la repercusión de ciertas variantes sobre el procesamiento del ARNm. Para ello, se empleó el plásmido pSPL3 en el que se introdujo la mutación a estudio, la transformación se realizó en bacterias E. coli electrocompetentes y la transfección en células HEK-293.
Mediante la secuenciación del panel de genes, se obtuvo una tasa diagnóstica del 60%. Las mutaciones en los pacientes resueltos se distribuyeron en 30 genes diferentes, de las cuales 38 se describen por primera vez en este trabajo. Los genes mutados con mayor frecuencia en estos pacientes fueron ABCA4, USH2A, RPGR y PRPH2. Adicionalmente, se identificaron ocho variantes de número de copias en los genes EYS, ABCA4, PRPF31, MERTK, CRB1 y ROM1, demostrando el enorme potencial de estas tecnologías. En total, se reclasificaron el 10% de las familias estudiadas y se observó variabilidad fenotípica intra e inter familiar en pacientes con mutaciones en C1QTNF5, CERKL y PROM1. Además, destacamos que el 50% de las mujeres heterocigotas para RPGR y sintomáticas presentaron retinosis pigmentaria (RP) con asimetría interocular. Asimismo, se identificó un caso con posible digenismo entre los genes CNGA1 y CNGB1, y la duplicación completa de ROM1 en dos familias no relacionadas diagnosticadas de RP. Por otra parte, se han identificado seis familias con mutaciones en dos genes que potencialmente ambos podrían ser la causa de la DHR. En el ensayo funcional mediante minigenes, se observó que seis de las variantes analizadas presentaron un splicing aberrante.
Los resultados de esta tesis destacan la utilidad clínica de la secuenciación masiva dirigida para las DHR-NS y la importancia de un examen oftalmológico completo que nos permita establecer nuevas asociaciones genotipo-fenotipo y ampliar el conocimiento de este grupo de enfermedades. Identificar la causa de la enfermedad es esencial para mejorar el manejo del paciente, realizar un asesoramiento genético preciso y beneficiarse de los futuros tratamientos y ensayosclínicos basados en terapia génica. / [CA] Les distròfies hereditàries de la retina (DHR) són un conjunt de trastorns caracteritzats per la mort, generalment, progressiva de fotoreceptors i cèl¿lules de l'epiteli pigmentari retiniano. Les DHR afecten més de 2 milions de persones al món, produint una pèrdua parcial i, en molts casos, total de la visió, per la qual no hi ha cap tractament que revertisca o frene la progressió de la malaltia. Es caracteritzen per una elevada heterogeneïtat clínica i genètica, identificant-se fins a la data mutacions en més de 250 gens responsable d'algun tipus de DHR.
Esta tesi doctoral s'ha centrat en el diagnòstic genètic de 208 pacients afectats de DHR no sindròmica (DHR-NS), per mitjà de seqüenciació massiva dirigida a un panell de 117 gens i cinc regions intròniques profundes en les que prèviament s'havien descrit mutacions. Les variants identificades en els pacients es van prioritzar d'acord a la mínima freqüència allèlica i es van classificar segons els criteris de la guia de l'American College of Medical Genetics and Genomics. Les variants de nombre de còpies identificades per mitjà de la seqüenciació del panell es van validar utilitzant multiplex ligation-dependent probe amplification o array genòmic. A tots els pacients se'ls va realitzar un estudi oftalmològic, més o menys exhaustiu, incloent proves electrofisiològiques. A més, es van realitzar assajos in vitro amb minigens per comprovar la repercussió de certes variants sobre el processament de l'ARNm. Per a això, es va emprar el plasmidi pSPL3 en què es va introduir la mutació a estudi, la transformació es va realitzar en bacteris E. coli electrocompetentes i la transfecció en cèl-lules HEK-293.
Per mitjà de la seqüenciació del panell de gens, es va obtindre una taxa diagnòstica del 60%. Les mutacions en els pacients resolts es van distribuir en 30 gens diferents, de les quals 38 es descriuen per primera vegada en este treball. Els gens mutats amb major freqüència en estos pacients van ser ABCA4, USH2A, RPGR i PRPH2. Addicionalment, es van identificar huit variants de nombre de còpies en els gens EYS, ABCA4, PRPF31, MERTK, CRB1 i ROM1, demostrant l'enorme potencial d'estes tecnologies. En total, es van reclassificar el 10% de les famílies estudiades i es va observar variabilitat fenotípica intra i inter familiar en pacients amb mutacions en C1QTNF5, CERKL i PROM1. A més, destaquem que el 50% de les dones heterozigotes per RPGR i simptomàtiques van presentar retinosi pigmentària (RP) amb asimetria interocular.
Així mateix, es va identificar un cas amb possible digenismo entre els gens CNGA1 i CNGB1, i la duplicació completa de ROM1 en dues famílies no relacionades diagnosticades de RP. D'altra banda, s'han identificat sis famílies amb mutacions en dos gens que potencialment ambdós podrien ser la causa de la DHR. En l'assaig funcional per mitjà de minigens, es va observar que sis de les variants analitzades van presentar un splicing aberrant.
Els resultats d'esta tesi destaquen la utilitat clínica de la seqüenciació massiva dirigida per a les DHR-NS i la importància d'un examen oftalmològic complet que ens permeta establir noves associacions genotip-fenotip i ampliar el coneixement d'este grup de malalties. Identificar la causa de la malaltia és essencial per millorar el maneig del pacient, realitzar un assessorament genètic precís i beneficiar-se dels tractaments basats en teràpia gènica. / [EN] Inherited retinal dystrophies (IRD) are a group of disorders generally characterized by the progressive death of photoreceptors and retinal pigment epithelial cells. IRD affect more than 2 million people in the world, producing a partial and, in many cases, total loss of vision, for which there is no treatment that reverses or slows the progression of the disease. They are characterized by a high clinical and genetic heterogeneity, identifying mutations in more than 250 genes responsible for some type of IRD to date.
This doctoral thesis has focused on the genetic diagnosis of 208 patients affected by non-syndromic IRD (NS-IRD), through targeted genomic sequencing focuses on a panel of 117 genes and five deep intronic regions in which mutations have previously been identified. The identified variants in patients are prioritized according to the minimum allelic frequency and are classified according to the criteria of the American College of Medical Genetics and Genomics guide. The copy number variants identified by panel sequencing were validated using multiplex ligation-dependent probe amplification or genomic array. All patients underwent an ophthalmological study, more or less comprehensive, including electrophysiological tests. In addition, in vitro assays with minigenes were performed to verify the impact of certain variants on mRNA processing. To do this, pSPL3 plasmid in which the mutation was introduced was used, the transformation was performed in electrocompetent E. coli bacteria and transfection in HEK-293 cells.
By the panel sequencing, a diagnostic rate of 60% was obtained. The mutations in the resolved patients were distributed in 30 different genes, of which 38 were described for the first time in this work. The most frequently mutated genes in these patients were ABCA4, USH2A, RPGR and PRPH2. In addition, eight copy number variants were identified in the genes EYS, ABCA4, PRPF31, MERTK, CRB1 and ROM1, that demonstrated the enormous potential of these technologies. In total, 10% of the families studied were reclassified and intra and inter-family phenotypic variability was detected in patients with mutations in C1QTNF5, CERKL and PROM1. In addition, we highlight that 50% of the symptomatic and heterozygous RPGR women showed retinitis pigmentosa (RP) with interocular asymmetry. Likewise, we identified a case with possible digenism between the CNGA1 and CNGB1 genes, and the complete duplication of ROM1 in two unrelated families diagnosed with RP. On the other hand, six families have been identified with mutations in two genes that could potentially be the cause of IRD. Functional assays by minigenes showed that six of the studied variants affected splicing.
The results of this thesis highlight the clinical utility of targeted genomic sequencing in IRD and the importance of a complete ophthalmological examination that allows us to establish new genotype-phenotype associations and expand the knowledge of this group of diseases. Identifying the cause of the disease is essential to improve patient management, to perform an accurate genetic counseling and to take advantage of treatments based on gene therapy. / Rodríguez Muñoz, A. (2020). High-throughput strategies for molecular diagnosis of nonsyndromic inherited retinal dystrophies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/139095
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Sequence capture as a tool to understand the genomic basis for adaptation in angiosperm and gymnosperm treesSuren, Haktan 21 June 2017 (has links)
Forest trees represent a unique group of organisms combined with ecological and economic importance. Owing to their random mating system and widespread geographical distribution, they harbor abundance genetic variation both within and among populations. Despite their importance, research in forest trees has been underrepresented majorly due to their large and complex genome and scarce funding. However, recent climate change and other associated problems such as insect outbreaks, diseases and stress related damages have urged scientists to focus more on trees. Furthermore, the advent in high-throughput sequencing technologies have allowed trees to be sequenced and used as reference genome, which provided deeper understanding between genotype and environment. Whole genome sequencing is still not possible for organisms having large genomes including most tree species, and it is still not feasible economically for population genomic studies which require sequencing hundreds of samples. To get around this problem, genomic reduction is required. Sequence capture has been one of the genomic reduction techniques enabled studying the subset of the DNA of interest. In this paper, our primary goal is to outline challenges, provide guidance about the utility of sequence capture in trees, and to leverage such data in genome-wide association analyses to find the genetic variants that underlie complex, adaptive traits in spruce and pine, as well as poplar. Results of this research will facilitate bridging the genomic information gap between trees and other organisms. Moreover, it will provide better understanding how genetic variation governs phenotype in trees, which will facilitate both marker assisted selection for improved traits as well as provide guidance to determine forest management strategies for reforestation to mitigate the effects of climate change. / Ph. D. / Forests are under extensive threat including increased demand in wood consumption, climate changes and associated diseases and stress related damages. Up until very recently, researches in trees have been relatively slower owing to their large and complex genomes. However, this has dramatically changed mainly due to the advancement in sequencing technology. There have been more and more studies performed identifying novel genes that are responsible for improved characteristics. In this study, we provided guidance about how to better utilize sequencing technology and identified genes that are potentially related with adaptation in trees.
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A Genomic Approach to Resolving Relapse versus Reinfection among Four Cases of Buruli UlcerEddyani, M., Vandelannoote, K., Meehan, Conor J., Bhuju, S., Porter, J.L., Aguiar, J., Seemann, T., Jarek, M., Singh, M., Portaels, F., Stinear, T.P., de Jong, B.C. 24 September 2019 (has links)
Yes / Background.
Increased availability of Next Generation Sequencing (NGS) techniques allows, for the first time,
to distinguish relapses from reinfections in patients with multiple Buruli ulcer (BU) episodes.
Methodology.
We compared the number and location of single nucleotide polymorphisms (SNPs) identified by genomic screening between four pairs of Mycobacterium ulcerans isolates collected
at the time of first diagnosis and at recurrence, derived from a collection of almost 5000 well
characterized clinical samples from one BU treatment center in Benin.
Principal Findings.
The findings suggest that after surgical treatment—without antibiotics—the second episodes were due to relapse rather than reinfection. Since specific antibiotics were introduced
for the treatment of BU, the one patient with a culture available from both disease episodes
had M. ulcerans isolates with a genomic distance of 20 SNPs, suggesting the patient was
most likely reinfected rather than having a relapse.
Conclusions.
To our knowledge, this study is the first to study recurrences in M. ulcerans using NGS, and
to identify exogenous reinfection as causing a recurrence of BU. The occurrence of reinfection highlights the contribution of ongoing exposure to M. ulcerans to disease recurrence,
and has implications for vaccine development. / This work was supported by the UBS Optimus Foundation (Zurich, Switzerland) and the Department of Economy, Science and Innovation of the Flemish Government (Belgium). KV was supported by a VLADOC PhD scholarship of VLIRUOS (Belgium).
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Sequenciamento e análise da variabilidade genética de vírus transmitidos por ácaros do gênero Brevipalpus no Brasil / Sequencing and analysis of the genetic variability of viruses transmitted by Brevipalpus mites in BrazilJesus, Camila Chabí de 20 January 2016 (has links)
Acredita-se que o Brasil é o centro de diversidade de vírus transmitidos por ácaros do gênero Brevipalpus (VTB). Alguns desses VTB infectam culturas fundamentais para o agronegócio brasileiro como citros e café, além de maracujá e de várias plantas ornamentais. Na última década os genomas de dois deles, Citrus leprosis virus C (CiLV-C) e Coffee ringspot virus (CoRSV) foram sequenciados, mas ainda é escasso o conhecimento sobre a diversidade genética e processos evolutivos envolvidos na população dessas espécies. Neste contexto, o objetivo deste trabalho foi caracterizar molecularmente novas estirpes de CiLV-C e CoRSV que infectam citros e café, respectivamente. E revelar as relações filogenéticas com espécies de VTB conhecidas, assim como avaliar a variabilidade genética da população de CiLVC no Brasil. Para o estudo de CiLV-C, 47 amostras de Citrus sinensis apresentando sintomas típicos da leprose dos citros foram coletadas em diferentes regiões do Brasil no período de 2011-2015. A presença de CiLV-C foi detectada por RT-PCR em todas as amostras coletadas e, posteriormente, foi realizado o sequenciamento de quatro regiões do genoma viral (p29, p15, RI e MP) de cada isolado. As sequências obtidas foram utilizadas no estudo de filogenia e variabilidade da população de CiLV-C no Brasil. Foi demonstrado que a população de CiLV-C apresenta uma variabilidade relativamente baixa; entretanto, foi identificada a existência de duas linhagens dentro da espécie, nomeadas Cor e SJRP. Os genomas completos de CiLV-C SJRP e também do dicorhavirus tentativo CoRSV identificado em Limeira, SP, foram obtidos mediante o sequenciamento de RNA de pequeno tamanho (siRNA). Cada sequência foi validada mediante o sequenciamento de fragmentos gerados por RT-PCR ao longo do genoma. CiLV-C SJRP apresenta cerca de 85% de identidade de nucleotídeo com o membro-tipo do gênero Cilevirus e exibe evidências de recombinação com isolados da linhagem Cor, a prevalente no território brasileiro. Globalmente, o genoma de CoRSV Limeira apresenta mais de 90% de identidade de nucleotídeo com isolado CoRSV Lavras, o que indica que ambos os isolados são membros da mesma espécie tentativa de dichorhavirus. / South America is most likely the center of diversity of Brevipalpus transmitted viruses (BTV). Some of these BTV infect major crops of the Brazilian agribusiness such as citrus and coffee. Passion fruit and several other ornamental plants are affected as well. The genome of two of these viruses, Citrus leprosis virus C (CiLV-C) and Coffee ringspot virus (CoRSV) were sequenced, but the knowledge about several molecular characteristics and processes involved in the evolution of their populations are still scarce. Thus, the objective of this study was to molecularly characterize new isolates of BTV infecting citrus and coffee, reveal the phylogenetic relationships with known species of BTV, and assess the genetic variability of the population of CiLV-C in Brazil. For CiLV-C studies, 47 samples of Citrus sinensis showing typical symptoms of leprosis were collected in different Brazilian regions during 2011-2015. The presence of CiLV-C was detected by RT-PCR in all the collected samples and four regions of the viral genome (p29, p15, IR and MP) of each isample were sequenced. It has been shown that the CiLV-C population has relatively low variability; although the existence of two lineages named Cor and SJRP were identified in this work. The complete genomes of one isolate of the lineage SJRP (CiLV-C SJRP) and that of the tentative dicorhavirus CoRSV found in Limeira, SP, were obtained by small RNA (siRNA) Sequencing. Validation was performed by sequencing fragments generated by RT-PCR using specific primers throughout the genome. CiLV-C SJRP has about 85% nucleotide identity with the genome of the type-member of the Cilevirus genus and shows evidence of recombination with isolates of the lineage Cor, which are prevalent in Brazil. CoRSV isolate Limeira has more than 90% of nucleotide identity with CoRSV Lavras, indicating that both isolates are members of the same tentative species of dichorhavirus.
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Sequenciamento e análise da variabilidade genética de vírus transmitidos por ácaros do gênero Brevipalpus no Brasil / Sequencing and analysis of the genetic variability of viruses transmitted by Brevipalpus mites in BrazilCamila Chabí de Jesus 20 January 2016 (has links)
Acredita-se que o Brasil é o centro de diversidade de vírus transmitidos por ácaros do gênero Brevipalpus (VTB). Alguns desses VTB infectam culturas fundamentais para o agronegócio brasileiro como citros e café, além de maracujá e de várias plantas ornamentais. Na última década os genomas de dois deles, Citrus leprosis virus C (CiLV-C) e Coffee ringspot virus (CoRSV) foram sequenciados, mas ainda é escasso o conhecimento sobre a diversidade genética e processos evolutivos envolvidos na população dessas espécies. Neste contexto, o objetivo deste trabalho foi caracterizar molecularmente novas estirpes de CiLV-C e CoRSV que infectam citros e café, respectivamente. E revelar as relações filogenéticas com espécies de VTB conhecidas, assim como avaliar a variabilidade genética da população de CiLVC no Brasil. Para o estudo de CiLV-C, 47 amostras de Citrus sinensis apresentando sintomas típicos da leprose dos citros foram coletadas em diferentes regiões do Brasil no período de 2011-2015. A presença de CiLV-C foi detectada por RT-PCR em todas as amostras coletadas e, posteriormente, foi realizado o sequenciamento de quatro regiões do genoma viral (p29, p15, RI e MP) de cada isolado. As sequências obtidas foram utilizadas no estudo de filogenia e variabilidade da população de CiLV-C no Brasil. Foi demonstrado que a população de CiLV-C apresenta uma variabilidade relativamente baixa; entretanto, foi identificada a existência de duas linhagens dentro da espécie, nomeadas Cor e SJRP. Os genomas completos de CiLV-C SJRP e também do dicorhavirus tentativo CoRSV identificado em Limeira, SP, foram obtidos mediante o sequenciamento de RNA de pequeno tamanho (siRNA). Cada sequência foi validada mediante o sequenciamento de fragmentos gerados por RT-PCR ao longo do genoma. CiLV-C SJRP apresenta cerca de 85% de identidade de nucleotídeo com o membro-tipo do gênero Cilevirus e exibe evidências de recombinação com isolados da linhagem Cor, a prevalente no território brasileiro. Globalmente, o genoma de CoRSV Limeira apresenta mais de 90% de identidade de nucleotídeo com isolado CoRSV Lavras, o que indica que ambos os isolados são membros da mesma espécie tentativa de dichorhavirus. / South America is most likely the center of diversity of Brevipalpus transmitted viruses (BTV). Some of these BTV infect major crops of the Brazilian agribusiness such as citrus and coffee. Passion fruit and several other ornamental plants are affected as well. The genome of two of these viruses, Citrus leprosis virus C (CiLV-C) and Coffee ringspot virus (CoRSV) were sequenced, but the knowledge about several molecular characteristics and processes involved in the evolution of their populations are still scarce. Thus, the objective of this study was to molecularly characterize new isolates of BTV infecting citrus and coffee, reveal the phylogenetic relationships with known species of BTV, and assess the genetic variability of the population of CiLV-C in Brazil. For CiLV-C studies, 47 samples of Citrus sinensis showing typical symptoms of leprosis were collected in different Brazilian regions during 2011-2015. The presence of CiLV-C was detected by RT-PCR in all the collected samples and four regions of the viral genome (p29, p15, IR and MP) of each isample were sequenced. It has been shown that the CiLV-C population has relatively low variability; although the existence of two lineages named Cor and SJRP were identified in this work. The complete genomes of one isolate of the lineage SJRP (CiLV-C SJRP) and that of the tentative dicorhavirus CoRSV found in Limeira, SP, were obtained by small RNA (siRNA) Sequencing. Validation was performed by sequencing fragments generated by RT-PCR using specific primers throughout the genome. CiLV-C SJRP has about 85% nucleotide identity with the genome of the type-member of the Cilevirus genus and shows evidence of recombination with isolates of the lineage Cor, which are prevalent in Brazil. CoRSV isolate Limeira has more than 90% of nucleotide identity with CoRSV Lavras, indicating that both isolates are members of the same tentative species of dichorhavirus.
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A Security Solution on Availability for Next Generation Telecommunication Networks Management Information SystemsWu, Ming-Yi 04 September 2009 (has links)
With the development of the internet protocol (IP) and digitization for the global telecommunication industry, the convergence rate of communications and broadcasting has been improved. According to these motives, the domestic telecommunication industry modify present commercial operation managements and combine with the communication networks, the fixed-mobile communication (FMC) networks, and the mobile communication networks into the all-internet protocol (all-IP) communication network structure based on the extended upgrade communication network system. The domestic telecommunication industry expect that the integrated heterogeneous network, including the speech data, the video data, and the communication services, which can provide the omnipresent customizable mobile communication network services and obtain the advance business opportunities in terms of the future development of digital convergence.
Hence, the domestic telecommunication industry not only build the next generation network structure to satisfy their demands, but also develop the management information system (MIS) to monitor the operation of telecommunication networks for ensure the quality of communication services and achieve the development of next generation networks. A primary consideration is to assure the usability of MIS for the telecommunication industry and the customers based on the profit rates and the omnipresent mobile network services, respectively¡C
However, the current status of the telecommunication industry that meet the many difficult challenges and problems to construct the next generation MIS. For examples, the all-IP-based open network structure will be used instead of the close network structure, the different generation telecommunication systems combine with the operation and maintenance information system, the information security incident, and so on. It is must to consider highly of these situations between the major links above. Otherwise, the service usability of MIS will be destroyed.
In this thesis, we adopt the case study approach to analyze the MIS construction process of the domestic telecommunication operator. During the build process, the MIS construction of next generation telecommunication networks must to suffice for the flexibility, the safety, and the stabilization and need to make sure the critical mission on stable operation condition, the lower service interruption, the higher usability. The implementation of the next generation MIS, which will help support the crucial operation procedure of the conglomerate and cope with the fast variation of the market demands.
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Towards next-generation sequencing-based identification of norovirus recognition elements and microfluidic array using phage display technology / Phage Display als Tool zur Next Generation Sequencing-basierten Identifizierung von Norovirus-Erkennungselementen und zur Entwicklung eines mikrofluidischen ArraysPahlke, Claudia 28 November 2017 (has links) (PDF)
Noroviruses are the major cause of acute viral gastroenteritis worldwide. Thus, rapid and reliable pathogen detection and control are crucial to avoid epidemic outbreaks. Peptides which bind to these viruses with high specificity and affinity could serve as small and stable recognition elements in biosensing applications for a point-of-care diagnostic of noroviruses. They can be identified by screening large phage display libraries using the biopanning technique.
In the present study, this method was applied to identify norovirus-binding peptide motifs. For this purpose, a biopanning based on column chromatography was established, and three rounds of selections were performed. After the second round, the cosmix-plexing recombination technique was implemented to enhance the chance of obtaining peptides with very high affinity. Biopanning data evaluation was based on next-generation sequencing (NGS), to show that this innovative method can enable a detailed analysis of the complete sequence spectrum obtained during and after biopanning. Highly enriched motifs could be characterized by their large proportion of the amino acids W, K, R, N, and F. Neighbourhood analysis was exemplarily performed for selected motifs, showing that the motifs FAT, RWN, and KWF possessed the fingerprints with the largest differences relative to the original library. This thesis thus presents next-generation sequencing-based analysis tools, which could now be transferred to any other biopanning project. The identified peptide motifs represent promising candidates for a future examination of their norovirus-specific binding.
A new option for testing such phage-target interactions in the context of biopanning selections was studied in the second part of the thesis. For this purpose, a phage-based microarray was developed as a miniaturized binding assay. As a prerequisite, the different immobilization behaviour of phages on positively and negatively charged surfaces was studied, and a non-contact printing technique for bacteriophages was developed. Subsequently, the interaction of phages and antibodies directed against phage coat proteins was characterized in enzyme-linked immunosorbent assays, and the protocol was successfully transferred to the non-contact printed phage spots. At the proof-of-concept level, the phage array could finally be integrated into a microfluidic setup, showing a higher signal-to-background ratio relative to the static phage array. These results point the way towards a microfluidic phage array, allowing online monitoring, automation, and parallelisation of the phage array analysis. / Noroviren gelten als Hauptursache akuter viraler Magen-Darm-Erkrankungen. Nur eine zeitnahe und verlässliche Detektion und Kontrolle dieser Pathogene kann epidemische Ausbrüche vermeiden. Um dies zu ermöglichen, könnten Peptide, die an diese Viren mit hoher Spezifität und Affinität binden, als kleine und stabile Erkennungselemente in biosensorischen Anwendungen eingesetzt werden. Solche Peptide können mithilfe der Biopanning-Technik identifiziert werden, die auf dem Screening großer Phagen-Display-Bibliotheken beruht.
In der vorliegenden Arbeit wurde diese Methode genutzt, um Norovirus-bindende Peptidmotive zu identifizieren. Dazu wurde ein auf Säulenchromatographie basierendes Biopanning entwickelt und drei Selektionsrunden durchgeführt. Die Cosmix-Plexing-Rekombinationstechnik wurde nach der zweiten Runde eingesetzt, um die Wahrscheinlichkeit der Gewinnung hochaffiner Binder zu erhöhen. Die Auswertung der Biopanningdaten erfolgte mittels Hochdurchsatzsequenzierung (Next-Generation Sequencing). Es konnte gezeigt werden, dass diese innovative Methode die detailierte Analyse des kompletten Sequenzspektrums während und nach dem Biopanning ermöglicht. Stark angereicherte Motive konnten durch ihren hohen Anteil an den Aminosäuren W, K, R, N und F charakterisiert werden. Eine Nachbarschaftsanalyse wurde exemplarisch für ausgewählte Motive durchgeführt. Dabei wurden die stärksten Unterschiede im Fingerprint im Vergleich zur Ausgangsbibliothek bei den Motiven FAT, RWN und KWF gefunden. Diese Dissertation stellt damit auf Next-Generation Sequencing basierende Analysetechniken vor, die für weitere Biopanningprojekte übernommen werden können. Die identifizierten Peptidmotive könnten als vielversprechende Kandidaten zukünftig auf ihre Norovirus-spezifische Bindung hin getestet werden.
Eine neue Möglichkeit, solche Phagen-Analyt-Interaktionen zu untersuchen, wurde im zweiten Teil der Dissertation untersucht. Dafür wurde als miniaturisierter Bindungsassay ein Phagen-basiertes Mikroarray entwickelt. Als Voraussetzung wurde zunächst das unterschiedliche Immobilisierungsverhalten von Bakteriophagen auf positiv und negativ geladenen Oberflächen untersucht und eine kontaktfreie Drucktechnik für Bakteriophagen etabliert. Anschließend wurde die Interaktion von Phagen und gegen sie gerichteten Antikörpern in Enzym-gekoppelten Immunadsorptionstests charakterisiert und das Protokoll erfolgreich auf die kontaktfrei gedruckten Phagenspots übertragen. Schließlich wurde erstmals die grundsätzliche Möglichkeit gezeigt, das Array in ein mikrofluidisches Setup zu integrieren, was zu einem höheren Signal-zu-Hintergrund-Verhältnis im Vergleich zum statischen Array führte. Diese Ergebnisse zeigen damit den Weg zu einem mikrofluidischen Phagen-Array auf, das sowohl die Möglichkeit des Online-Monitorings als auch der Automatisierung und Parallelisierung der Phagen-Array-Analyse bietet.
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Nachtrag zur Veranstaltung „Keine Sackgasse: Schnelles Internet und Straßenausbau im kommunalen Fokus“Kilian, Maike 13 June 2019 (has links)
Die Verfügbarkeit von Breitbandnetzen wird für die Sicherung und Weiterentwicklung des Wirtschafts-, Technologie- und Tourismusstandortes Sachsen immer wichtiger. Eine gute Nachricht gleich zu Beginn: Das Land Sachsen stellt seit Ende letzten Jahres Fördermittel für den Aufbau von Breitbandnetzen auch für die zukunftsfähigen Next-Generation-Access-Netze (NGA) zur Verfügung. Zuwendungsempfänger sind neben Gemeinden, Landkreisen, Verwaltungsgemeinschaften und Gemeindeverbände auch Eigenbetriebe und Zweckverbände. Das ließ viele Zuhörer auf der Informationsveranstaltung „Breitband und Straßen als kommunale Herausforderung“ am 26. März 2015 in Leipzig aufhorchen.
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A critical appraisal of the European Commission´s policy towards regulating next generation communications networksBriglauer, Wolfgang, Gugler, Klaus January 2012 (has links) (PDF)
Fiber-deployment of telecommunications networks is currently a great challenge for sector-specific
regulators, national governments, as well as for investing operators. One of the most controversial
regulatory issues in Europe (and elsewhere) is whether the emerging next generation access (NGA)
infrastructure should be subjected to cost-based access regulation or whether at least a temporary
removal of ex ante obligations ("regulatory holidays") should be granted.
In answering this question we examine the current and foreseeable EU regulatory framework and
show that it does not provide positive incentives for NGA deployment and increasing penetration
rates. On the basis of an international comparison with the most recent data on NGA deployment and
penetration, it appears, in turn, that deregulatory and/or state aid driven approaches targeted at the
demand (subscribers) and supply side (coverage) are more promising. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
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Efficient contracts for government intervention in promoting next generation communications networksBriglauer, Wolfgang, Holzleitner, Christian 07 1900 (has links) (PDF)
Although the future socio-economic benefits of a new fibre-based ("next generation access", NGA) telecommunications infrastructure seem to be uncontroversial, most countries have to date only undertaken NGA investments on a small scale. Accordingly, a universal NGA coverage appears to be a rather unrealistic objective without government intervention. Indeed, many governments have already initiated diverse subsidy programs in order to stimulate NGA infrastructure deployment. We contend, however, that the current contract practice of fixing ex ante targets for network expansion is inefficient given the uncertainty about future returns on NGA infrastructure-based services and the public authorities' incomplete information about the capital costs of the network provider. This paper puts forward to delegate the choice of the network expansion to the NGA provider. Simple linear profit-sharing contracts can be designed to control the NGA provider's incentives and to put in balance the public objectives of network expansion and limitation of public expenditure. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
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