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Development of quantitative PCR methods for diagnosis of bacterial vaginosis and vaginal yeast infectionEiderbrant, Kristina January 2011 (has links)
Vaginitis is a vaginal infection which affects many women all over the world. The disorder is characterized by an infection of the vaginal area which can cause problems like abnormal vaginal discharge, itching and redness. The two most common causes of vaginitis are bacterial vaginosis and Candida vaginitis. The prevalence of bacterial vaginosis in Sweden is around 10-20 % and approximately 75 % of all women will once in their lifetime suffer from vaginal yeast infection. The clinical symptoms of vaginal infections are not specific and the diagnosis methods of bacterial vaginosis and Candida vaginitis are subjective and depended on the acuity of the clinician. Due to the lack of standardized and objective diagnostic tools, misdiagnosis and consequently incorrect treatment may occur. As vaginal infections and symptoms impact greatly of women´s quality of life and vaginitis have been associated with serious public health consequences, it is essential to diagnose and treat the conditions correctly. Hence, there is a great need of better methods of diagnosing these conditions. The aim of this master thesis was to develop quantitative species-specific real-time PCR assays to use in diagnosing the two most common causes of vaginitis i.e. bacterial vaginosis and Candida vaginitis. Potential markers for bacterial vaginosis (Atopobium vaginae, BVAB2, Gardnerella vaginalis, Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus iners, Megasphaera type 1, Megasphaera type 2, Mobiluncus curtisii, Mobiluncus mulieris and Leptotrichia/Sneathia species) and Candida vaginitis (Candida albicans, Candida glabrata, Candida parapsilosis and Candida tropicalis) were chosen. Primers and probes were designed and tested on reference strains and vaginal samples. Single- and multiplex PCR reactions were successfully optimized with the designed oligonucleotides. Furthermore, standard curves with excellent linearity were created and covered more than five orders of magnitude. These developed quantitative species-specific real-time PCR assays will, in a prospective medical validation, quantify 300 vaginal samples from women visiting the RFSU Clinic in Stockholm.
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On Transcriptome SequencingKlevebring, Daniel January 2009 (has links)
This thesis is about the use of massive DNA sequencing to investigate the transcriptome. During recent decades, several studies have made it clear that the transcriptome comprises a more complex set of biochemical machinery than was previously believed. The majority of the genome can be expressed as transcripts; and overlapping and antisense transcription is widespread. New technologies for the interroga- tion of nucleic acids have made it possible to investigate such cellular phenomena in much greater detail than ever before. For each application, special requirements need to be met. The work presented in this thesis focuses on the transcrip- tome and the development of technology for its analysis. In paper I, we report our development of an automated approach for sample preparation. The procedure was benchmarked against a publicly available reference data set, and we note that our approach outperformed similar manual procedures in terms of reproducibility. In the work reported in papers II-IV, we used different massive sequencing technologies to investigate the transcriptome. In paper II we describe a concatemerization approach that increased throughput by 65% using 454 sequencing,and we identify classes of transcripts not previously described in Populus. Papers III and IV both report studies based on SOLiD sequencing. In the former, we investigated transcripts and proteins for 13% of the human gene and detected a massive overlap for the upper 50% transcriptional levels. In the work described in paper IV, we investigated transcription in non-genic regions of the genome and detected expression from a high number of previ- ously unknown loci. / QC 20100723
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Ribosome display for selection and evolution of affibody moleculesGrimm, Sebastian January 2011 (has links)
Affinity proteins are invaluable tools in biotechnological and medical applications. This thesis is about combinatorial protein engineering principles for the generation of novel affinity proteins to purify mouse immunoglobulin, detect a potential cancer marker protein or inhibit a cell proliferation pathway. In a first study, ribosome display was for the first time applied to the selection of so-called affibody molecules, including the design of a ribosome display gene cassette, initial test enrichment experiments and the selection of binders against murine IgG1. One of the selected binders (ZMAB25) showed a highly selective binding profile to murine IgG1, which was exploited in the recovery of two different mouse monoclonal IgG1 antibodies from a bovine immunoglobulin-containing background. Ribosome display was further applied to the selection of affibody molecules binding to SATB1, a suggested marker protein for metastasizing adenocarcinoma. The study also included the selection of VHH antibody fragments from a naïve gene repertoire displayed on phage. Binders from both classes of protein scaffolds could be isolated that selectively recognized SATB1 but not its close homologue SATB2, and were used to detect endogenous SATB1 in Jurkat cells by immunofluorescence microscopy. The well-established phage display technology was used to select affibody molecules binding to H-Ras and Raf-1, both involved in the mitogen-activated protein kinase (MAPK) pathway and playing a central role in the control of cell proliferation, survival and differentiation. An isolated affibody molecule denoted ZRAF322 was found to selectively bind to Raf-1 and inhibit the interaction between H-Ras and Raf-1 in vitro. In a continued effort, ribosome display was applied to the affinity maturation of the ZRAF322 variant in a novel approach, based on repetitive cycles of diversification by error-prone PCR of the entire affibody gene and ribosome display selection, mimicking the principles of natural evolution. The method involved a monitoring of the progress of evolution and variants of ZRAF322 with 13- to 26-fold improved affinities were obtained, that contained different combinations of single or double amino acid substitutions in either previously randomized or framework positions. Implications of the substitutions for binder stability and selectivity were also investigated, showing that a higher affinity could be associated with a lower thermal melting point and that affinity-improved variants showed uncompromised binding selectivity to the hRaf-1 target. / QC 20110506
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Parallel target selection by trinucleotide threadingZajac, Pawel January 2009 (has links)
DNA is the code for all life. Via intermediary RNA the information encoded by the genome is relayed to proteins executing the various functions in a cell. Together, this repertoire of inherently linked biological macromolecules determines all characteristics and features of a cell. Technological advancements during the last decades have enabled the pursuit of novel types of studies and the investigation of the cell and its constituents at a progressively higher level of detail. This has shed light on numerous cellular processes and on the underpinnings of several diseases. For the majority of studies focusing on nucleic acids, an amplification step has to be implemented before an analysis, scoring or interrogation method translates the amplified material into relevant biological information. This information can, for instance, be the genotype of particular SNPs or STRs, or the abundance level of a set of interesting transcripts. As such, amplification plays a significant role in nucleic acid assays. Over the years, a number of techniques – most notably PCR – has been devised to meet this amplification need, specifically or randomly multiplying desired regions. However, many of the approaches do not scale up easily rendering comprehensive studies cumbersome, time-consuming and necessitating large quantities of material.Trinucleotide threading (TnT) – forming the red thread throughout this thesis – is a multiplex amplification method, enabling simultaneous targeted amplification of several nucleic acid regions in a specific manner. TnT begins with a controlled linear DNA thread formation, each type of thread corresponding to a segment of interest, by a gap-fill reaction using a restricted trinucleotide set. The whole collection of created threads is subsequently subjected to an exponential PCR amplification employing a single primer pair. The generated material can thereafter be analyzed with a multitude of readout and detection platforms depending on the issue or characteristic under consideration.TnT offers a high level of specificity by harnessing the inherent specificities of a polymerase and a ligase acting on a nucleotide set encompassing three out of the four nucleotide types. Accordingly, several erroneous events have to occur in order to produce artifacts. This necessitates override of a number of control points.The studies constituting this thesis demonstrate integration of the TnT amplification strategy in assays for analysis of various aspects of DNA and RNA. TnT was adapted for expression profiling of intermediately-sized gene sets using both conventional DNA microarrays and massively parallel second generation 454 sequencing for readout. TnT, in conjunction with 454 sequencing, was also employed for allelotyping, defined as determination of allele frequencies in a cohort. In this study, 147 SNPs were simultaneously assayed in a pool comprising genomic DNA of 462 individuals. Finally, TnT was recruited for parallel amplification of STR loci with detection relying on capillary gel electrophoresis. In all investigations, the material generated with TnT was of sufficient quality and quantity to produce reliable and accurate biological information.Taken together, TnT represents a viable multiplex amplification technique permitting parallel amplification of genomic segments, for instance harboring polymorphisms, or of expressed genes. In addition to these, this versatile amplification module can be implemented in assays targeting a range of other features of genomes and transcriptomes. / QC 20100819
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TARP Promoter-Based Prostate Cancer Gene Therapy : From Development to ApplicationCheng, Wing-Shing January 2005 (has links)
<p>Prostate cancer is one leading cause of cancer-related death among men in Western countries. The standard therapies for localized prostate cancer include radical prostatectomy and radiation therapy. Such measures are relatively effective in the short term, but many patients ultimately relapse. These patients may benefit from a combination of standard therapy and oncolytic virus therapy. My work aimed to develop viruses for this purpose.</p><p>TARP is a protein that in males is specifically expressed in prostate epithelial and cancer cells. In my thesis, I characterized the TARP promoter and showed that TARP expression is regulated at the transcriptional level by testosterone through binding of the androgen receptor in the proximal TARP promoter. I further developed TARP promoter-based regulatory sequences for prostate-specific gene expression. A sequence comprising a PSA enhancer, a PSMA enhancer and the TARP promoter was constructed and designated PPT. An adenoviral vector containing the PPT sequence shielded from transcriptional interference by an H19 insulator showed high prostate-specific transcriptional activity in human cells both in the presence and absence of testosterone. However, in experimental murine prostate cancer the PPT sequence is not active. Therefore, a two-step transcriptional amplification (TSTA) system was used together with the PPT sequence to develop an adenovirus that confers prostate-specific transgene expression also in murine cells.</p><p>I constructed a conditionally replicating adenovirus where the E1A gene expression is controlled by an H19 insulator-shielded PPT regulatory sequence, Ad[I/PPT-E1A]. This virus exhibited absolute prostate specificity in terms of E1A expression, viral replication and cytolysis <i>in vitro</i> and <i>in vivo</i>. Importantly, our virus is active both in the presence and absence of testosterone, which may prove beneficial for patients treated by hormonal withdrawal. </p><p>Hopefully, my work will improve existing gene therapy strategies for prostate cancer and in the long term improve the prognosis for patients with prostate cancer.</p>
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Computational and experimental approaches to regulatory genetic variationAndersen, Malin January 2007 (has links)
Genetic variation is a strong risk factor for many human diseases, including diabetes, cancer, cardiovascular disease, depression, autoimmunity and asthma. Most of the disease genes identified so far alter the amino acid sequences of encoded proteins. However, a significant number of genetic variants affecting complex diseases may alter the regulation of gene transcription. The map of the regulatory elements in the human genome is still to a large extent unknown, and it remains a challenge to separate the functional regulatory genetic variations from linked neutral variations. The objective of this thesis was to develop methods for the identification of genetic variation with a potential to affect the transcriptional regulation of human genes, and to analyze potential regulatory polymorphisms in the CD36 glycoprotein, a candidate gene for cardiovascular disease. An in silico tool for the prediction of regulatory polymorphisms in human genes was implemented and is available at www.cisreg.ca/RAVEN. The tool was evaluated using experimentally verified regulatory single nucleotide polymorphisms (SNPs) collected from the scientific literature, and tested in combination with experimental detection of allele specific expression of target genes (allelic imbalance). Regulatory SNPs were shown to be located in evolutionary conserved regions more often than background SNPs, but predicted transcription factor binding sites were unable to enrich for regulatory SNPs unless additional information linking transcription factors with the target genes were available. The in silico tool was applied to the CD36 glycoprotein, a candidate gene for cardiovascular disease. Potential regulatory SNPs in the alternative promoters of this gene were identified and evaluated in vitro and in vivo using a clinical study for coronary artery disease. We observed association to the plasma concentrations of inflammation markers (serum amyloid A protein and C-reactive protein) in myocardial infarction patients, which highlights the need for further analyses of potential regulatory polymorphisms in this gene. Taken together, this thesis describes an in silico approach to identify putative regulatory polymorphisms which can be useful for directing limited laboratory resources to the polymorphisms most likely to have a phenotypic effect.
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TARP Promoter-Based Prostate Cancer Gene Therapy : From Development to ApplicationCheng, Wing-Shing January 2005 (has links)
Prostate cancer is one leading cause of cancer-related death among men in Western countries. The standard therapies for localized prostate cancer include radical prostatectomy and radiation therapy. Such measures are relatively effective in the short term, but many patients ultimately relapse. These patients may benefit from a combination of standard therapy and oncolytic virus therapy. My work aimed to develop viruses for this purpose. TARP is a protein that in males is specifically expressed in prostate epithelial and cancer cells. In my thesis, I characterized the TARP promoter and showed that TARP expression is regulated at the transcriptional level by testosterone through binding of the androgen receptor in the proximal TARP promoter. I further developed TARP promoter-based regulatory sequences for prostate-specific gene expression. A sequence comprising a PSA enhancer, a PSMA enhancer and the TARP promoter was constructed and designated PPT. An adenoviral vector containing the PPT sequence shielded from transcriptional interference by an H19 insulator showed high prostate-specific transcriptional activity in human cells both in the presence and absence of testosterone. However, in experimental murine prostate cancer the PPT sequence is not active. Therefore, a two-step transcriptional amplification (TSTA) system was used together with the PPT sequence to develop an adenovirus that confers prostate-specific transgene expression also in murine cells. I constructed a conditionally replicating adenovirus where the E1A gene expression is controlled by an H19 insulator-shielded PPT regulatory sequence, Ad[I/PPT-E1A]. This virus exhibited absolute prostate specificity in terms of E1A expression, viral replication and cytolysis in vitro and in vivo. Importantly, our virus is active both in the presence and absence of testosterone, which may prove beneficial for patients treated by hormonal withdrawal. Hopefully, my work will improve existing gene therapy strategies for prostate cancer and in the long term improve the prognosis for patients with prostate cancer.
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In vitro and in vivo approaches in the characterization of XTH gene productsKaewthai, Nomchit January 2011 (has links)
ABSTRACT The xyloglucan endo-transglycosylase/hydrolase (XTH) genes are found in all vascular and some nonvascular plants. The XTH genes encode proteins which comprise a subfamily of glycoside hydrolase (GH) family 16 in the Carbohydrate-Active enZYmes (CAZY) classification. The XTH gene products are believed to play intrinsic role in cell wall modification during growth and development throughout the lifetime of the plant. In the present investigation, biochemical and reverse genetic approaches were used to better understand the functions of individual members of the XTH gene family of two important plants: the model organism Arabidopsis thaliana and the grain crop barley (Hordeum vulgare). A phylogenetic tree of the xyloglucan-active enzymes of GH16 has previously been constructed, where enzymes with similar activities have been shown to cluster together. Several members of phylogenetic Group I/II and III-B, predicted to exhibit xyloglucan endo-transglycosylase activity (EC 2.4.1.207) and members of Group III-A, predicted to exhibit xyloglucan endo-hydrolase activity (EC 3.2.1.151), were included to analyze the functional diversity of XTH gene products. A heterologous expression system using the yeast Pichia pastoris was found to be effective for recombinant protein production with a success rate of ca. 50%. XTH gene products were obtained in soluble and active forms for subsequent biochemical characterization. In order to be able to screen larger numbers of protein producing clones, a fast and easy method is required to identify clones expressing active protein in high enough amounts. Thus, a miniaturized XET/XEH assay for high-throughput analysis was developed, which was able to identify activities with good precision and with a reduced time and materials consumption and a reduced work load. Enzyme kinetic analysis indicated that the XET or XEH activity of all XTH gene products characterized in the present study corresponded to predictions based on the previously revised phylogenetic clustering. To gain insight into the biological function of the predominant XEHs AtXTH31 and AtXTH32, which are highly expressed in rapidly developing tissues, a reverse genetic approach was employed using T-DNA insertion lines of the A. thaliana Columbia ecotype. Genotypic and phenotypic characterization, together with in situ assays of XET and XEH activities, in single- and double-knock-out mutants indicated that these Group III-A enzymes are active in expanding tissues of the A. thaliana roots and hypocotyl. Although suppression of in muro XEH activity was clearly observed in the double-knock-out, no significant growth phenotype was observed, with the exception that radicle emergence appeared to be faster than in the wild type plants. Keywords: Arabidopis thaliana, Hordeum vulgare, plant cell wall, xyloglucan, glycoside hydrolase family 16, xyloglucan endo-transglycosylase/hydrolase gene family, xyloglucan endo-transglycosylase, xyloglucan endo-hydrolase, heterologous protein expression, Pichia pastoris, T-DNA insertion, in situ XET/XEH assay, high-throughput screening / QC 20110114
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