京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18122号 / 理博第4000号 / 新制||理||1577(附属図書館) / 30980 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 村山 美穂, 教授 幸島 司郎, 教授 伊谷 原一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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Advances in next-generation sequencing (NGS) technologies have resulted in significant reduction of cost per sequenced base pair and increase in sequence data volume. On the other hand, most currently used NGS technologies produce relatively short sequence reads (50 - 150 bp) compared to Sanger sequencing (~700 bp). This represents an additional challenge in data analysis, because shorter reads are more difficult to assemble. At this point, production of sequencing data outpaces our capacity to analyze them. Newer NGS technologies capable of producing longer reads are emerging, which should simplify and speed up genome assembly. However, this will only increase the number of sequenced genomes without structural and functional annotation. In addition to multiple scientific initiatives to sequence thousands of genomes, personalized medicine centered on sequencing and analysis of individual human genomes will become more available. This poses a challenge for computer science and emphasizes the importance of developing new computational algorithms, methodology, tools, and pipelines. This dissertation focuses on development of these software tools, methodologies, and resources to help address the need for processing of volumes of data generated by new sequencing technologies. The research concentrated on genome structure analysis, individual variation, and comparative biology. This dissertation presents: (1) the Short Read Classification Pipeline (SRCP) for preliminary genome characterization of unsequenced genomes; (2) a novel methodology for phylogenetic analysis of closely related organisms or strains of the same organism without a sequenced genome; (3) a centralized online resource for standardized gene nomenclature. Utilizing the SRCP and the methodology for initial phylogenetic analysis developed in this dissertation enables positioning the organism in the evolutionary context. This should facilitate identification of orthologs between the species and paralogs within the species even in the initial stage of the analysis when only exome is sequenced and, thus, enable functional annotation by transferring gene nomenclature from well-annotated 1:1 orthologs, as required by the online standardized gene nomenclature resource developed in this dissertation. Thus, the tools, methodology, and resources presented here are tied together in following the initial analysis workflow for structural and functional annotation.

Emerging sequencing approaches have revolutionized the way we can collect DNA sequence data for applications in bioforensics and biosurveillance. In this research, we present an approach to construct a database of known biological agents and use this database to develop a statistical framework to analyze raw reads from next-generation sequence data for species identification and strain attribution. Our method capitalizes on a Bayesian statistical framework that accommodates information on sequence quality, mapping quality and provides posterior probabilities of matches to a known database of target genomes. Importantly, our approach also incorporates the possibility that multiple species can be present in the sample or that the target strain is not even contained within the reference database. Furthermore, our approach can accurately discriminate between very closely related strains of the same species with very little coverage of the genome and without the need for genome assembly - a time consuming and labor intensive step. We demonstrate our approach using genomic data from a variety of known bacterial agents of bioterrorism and agents impacting human health.

Yes / Introduction: Mobile phones are used the world over, including in healthcare settings. This study aimed to investigate the viable microbial colonisation of mobile phones used by healthcare personnel. Methods: Swabs collected on the same day from 30 mobile phones belonging to healthcare workers from three separate paediatric wards of an Australian hospital were cultured on five types of agar plate, then colonies from each phone were pooled, extracted and sequenced by shotgun metagenomics. Questionnaires completed by staff whose phones were sampled assisted in the analysis and interpretation of results. Results and discussion: All phones sampled cultured viable bacteria. Overall, 399 bacterial operational taxonomic units were identified from 30 phones, with 1432 cumulative hits. Among these were 58 recognised human pathogenic and commensal bacteria (37 Gram-negative, 21 Gram-positive). The total number of virulence factor genes detected was 347, with 1258 cumulative hits. Antibiotic resistance genes (ARGs) were detected on all sampled phones and overall, 133 ARGs were detected with 520 cumulative hits. The most important classes of ARGs detected encoded resistance to beta-lactam, aminoglycoside and macrolide antibiotics and efflux pump mediated resistance mechanisms. Conclusion: Mobile phones carry viable bacterial pathogens and may act as fomites by contaminating the hands of their users and indirectly providing a transmission pathway for hospital-acquired infections and dissemination of antibiotic resistance. Further research is needed, but meanwhile adding touching mobile phones to the five moments of hand hygiene is a simple infection control strategy worth considering in hospital and community settings. Additionally, the implementation of practical and effective guidelines to decontaminate mobile phone devices would likely be beneficial to the hospital population and community at large.

No description available.

Introduction: Sepsis is a major source of morbidity and mortality in neonates; however, identification of the causative pathogens can be challenging. Next generation sequencing (NGS) is a high-throughput, parallel sequencing technique for DNA. Pathogen-targeted enrichment followed by NGS has the potential to be more sensitive and faster than current gold-standard blood culture. In this pilot study, we will test the feasibility and pathogen detection patterns of pathogen-targeted NGS in neonates with suspected sepsis. Additionally, the distribution and diagnostic accuracy of cell-free DNA and protein C levels at two time points will be explored. Methods: We will conduct a prospective, pilot observational study. Neonates over 1 kg with suspected sepsis from a single tertiary care children’s hospital will be recruited for the study. Recruitment will be censored at 200 events or 6 months duration. Two blood study samples will be taken: the first simultaneous to the blood culture (time = 0 hr, for NGS and biomarkers) via an exception to consent (deferred consent) and another 24 hours later after prospective consent (biomarkers only). Neonates will be adjudicated into those with clinical sepsis, culture-proven sepsis and without sepsis based on clinical criteria. Feasibility parameters (e.g. recruitment) and NGS process time will be reported. Analysis: NGS results will be described in aggregate, compared to the simultaneous blood culture (sensitivity and specificity) and reviewed via expert panel for plausibility. Pilot data for biomarker distribution and diagnostic accuracy (sensitivity and specificity) for distinguishing between septic and non-septic neonates will be reported. Study amendment and interim results: After obtaining ethics approval, study enrolment started October 15, 2020. Interim feasibility results showed successful deferred consent, but low enrolment. A study amendment was used to increase enrolment, create pre-packaged blood kits and implement a substitute decision maker Notification form. / Thesis / Master of Health Sciences (MSc)

Chaperone proteins are essential components in the maintenance and turnover of the proteome. Many chaperones play integral functions in the folding and unfolding of cellular substrates under many conditions, including heat stress. Most chaperones can be characterized into two categories; the typical ATP dependent chaperones and the ATP independent chaperones. One ATP independent chaperone class it the Small Heat Shock Proteins (sHSPs), which as molecular life vests and are thought to protect misfolding proteins from irreversible aggregation. One such organism, the cyanobacterium Synechocystis sp. PCC 6803, is an excellent model for the study and understanding of these proteins and their functions in vivo. The genome of Synechocystis encodes only one sHSP, Hsp16.6, and it has be shown to be essential for acquired thermotolerance. Two mutant derivatives of Hsp16.6 with single amino acid substitutions in the N-terminal arm (L9P and E25K) have loss-of-function phenotypes similar to knock out strains, but each has very different biochemical properties. The mutant L9P has an inability to interact with putative substrates during heat stress in vivo, while the mutant E25K appears unable to release substrates. Using a directed evolution approach, suppressors have been isolated that recover the lost thermotolerance of their respective parent strains, either L9P (16 suppressors) or E25K (10 suppressors). Illumina sequencing and comparative genomics have been used to identify alterations in the genomes of the suppressor strains in order to define genetic circuits involved in thermotolerance.

The epigenome carries dynamic information that controls gene expression and maintains cell identity during both disease and normal development. The inherent plasticity of the epigenome paves new avenues for developing diagnostic and therapeutic tools for human diseases. Microfluidic technology has improved the sensitivity and resolution of epigenomic analysis due to its outstanding ability to manipulate nanoliter-scale liquid volumes. In this thesis, I report three projects focusing on low-input, cell-type-specific and spatially resolved histone modification profiling on microfluidic platforms. First, I applied Microfluidic Oscillatory Washing-based Chromatin Immunoprecipitation followed by sequencing (MOWChIP-seq) to study the effect of culture dimensionality, hypoxia stress and bacterium infection on histone modification landscapes of brain tumor cells. I identified differentially marked regions between different culture conditions. Second, I adapted indexed ChIPmentation and introduced mu-CM, a low-input microfluidic device capable of performing 8 assays in parallel on different histone marks using as few as 20 cells in less than 7 hours. Last, I investigated the spatially resolved epigenome and transcriptome of neuronal and glial cells from coronal sections of adult mouse neocortex. I applied unsupervised clustering to identify distinct spatial patterns in neocortex epigenome and transcriptome that were associated with central nervous system development. I demonstrated that our method is well suited for scarce samples, such as biopsy samples from patients in the context of precision medicine. / Doctor of Philosophy / Epigenetic is the study of alternations in organisms not caused by alternation of the genetic codes. Epigenetic information plays pivotal role during growth, aging and disease. Epigenetic information is dynamic and modifiable, and thus serves as an ideal target for various diagnostic and therapeutic strategies of human diseases. Microfluidics is a technology that manipulates liquids with extremely small volumes in miniaturized devices. Microfluidics has improved the sensitivity and resolution of epigenetic analysis. In this thesis, I report three projects focusing on low-input, cell-type-specific and spatially resolved histone modification profiling on microfluidic platforms. Histone modification is one type of epigenetic information and regulates gene expression. First, we studied the influence of culture condition and bacterium infection on histone modification profile of brain tumor cells. Second, we introduced mu-CM, combining a low-input microfluidic device with indexed ChIPmentation and is capable of performing 8 assays in parallel using as few as 20 cells. Last, we investigated spatial variations in the epigenome and transcriptome across adult mouse neocortex, the outer layer of brain involving in higher-order function, such as cognition. I identified distinct spatial patterns responsible for central nervous system development using machine learning algorithm. Our method is well suited for studying scarce samples, such as cells populations isolated from patients in the context of precision medicine.

[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