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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Investigating the Effect of Ethanol on Wnt7a and its Potential Implications in Fetal Alcohol Spectrum Disorder

Lytle, Erika 01 January 2020 (has links)
Fetal Alcohol Spectrum Disorders (FASDs), are caused by maternal alcohol consumption during pregnancy [3]. FASD encompasses a wide variety of cardiac and neural anomalies, while also associated with improper limb development, abnormal craniofacial features, problems within the central nervous system (CNS), and disabilities in learning and communication. Gene-regulating FASDs have not been well studied during the crucial phases of early embryonic development. Genes within the Wnt/Beta-catenin pathway control a vast amount of embryonic developmental processes. Among them is the Wnt7a gene, a significant downstream gene regulator which positively controls neural stem cell proliferation and cardiomyocyte differentiation on a large scale during early embryonic development. This project will serve to provide potential insight into the genes involved in FASD. We hypothesize that ethanol administration to early embryonic mice will suppress Wnt7a expression in the heart and brain, leading to FASD development. RNA-sequencing (RNA-Seq) and real-time quantitative PCR (qPCR) were used to measure Wnt7a gene expression within the early embryonic mouse heart and brain. After evaluation of RNA-Seq data and a comparative analysis using the 2-ΔΔCTmethod, it is evident Wnt7a is present in embryonic mouse age E10.5 heart and brain samples, and Wnt7a is suppressed at age E10.5 in embryonic mouse heart, but not brain, when induced with ethanol.
22

CPF1-BASED CRISPR GENOME EDITING IN THE CYANOBACTERIUM N. PUNCTIFORME

Woo, Soohan 01 January 2022 (has links)
CRISPR systems have been growing in their utility and their application throughout the biological field as researchers continue to grow in their understanding of the relatively novel genome editing technology. However, despite the potential of CRISPR as a genome editing tool, the complexity of applying this technology to a specific organism calls for custom modifications to the system to improve its success rate. In this project, a CRISPR-Cpf1 system that can be effectively employed in the cyanobacterium Nostoc punctiforme was designed, with a focus on the hormogonium development of this species. Multiple plasmids containing the CRISPR system and targeting different genes were constructed using a Gibson-based rapid assembly cloning method, and then were tested by introduction into Nostoc punctiforme via conjugation. Plasmids were constructed to mutate 7 different genes in N. punctiforme with 4 of the 7 successfully mutating their target genes. For one of the genes where the plasmid failed to produce mutants, the usage of a larger homology repair template (HRT) was found to enhance the efficiency of gene editing, allowing the gene to be knocked out. Thus, the length of the HRT appears to be a critical factor in designing successful constructs. The system developed in this project aims to make CRISPR a more viable tool in studying Nostoc cyanobacteria, and more specifically to aid in understanding the mechanisms behind hormogonium development in the studied species. This system may have a wider application for studying the Nostoc genus and related organisms, such as Anabaena.
23

Genome-wide variation in the distribution of transposable and repetitive elements in the Western Clawed Frog (Silurana tropicalis)

Shen, Jiangshan J. 10 1900 (has links)
<p>Repetitive elements, including tandem repeats and transposable elements (TE), are genetic features of all plant and animal genomes. Despite their abundance and the phylogenetic breadth of host genomes, factors that control the genome-wide distribution of repetitive elements are not well understood. Here we have evaluated the correlation between various genomic predictor variables such as gene expression level, distance from genes, and GC content, with the presence of TEs and non-TE repeats in two kilobase windows of the complete genome sequence of the Western Clawed Frog (<em>Silurana tropicalis</em>). We found that the distributions of different classes of TEs and repeats have distinct correlations with these predictor variables, including a generally strong negative correlation with proximity to exons and GC content. We also found that DNA transposons, but not retrotransposons, are preferentially inserted or preferentially retained near germline-expressed genes. Retrotransposons and simple repeats are found more often in or near conserved regions than expected by chance. These results offer insights into various models that have been proposed to account for heterogeneity in the genomic distribution of repetitive elements, most notably for the “gene disruption model” which posits that TE insertion and repeat presence near or in genes imposes costs to host fitness. In general, multiple lines of evidence suggests that the nature of natural selection on TE and other repetitive element evolution in this frog appears to be similar to that acting on TE and other repetitive elements in the human genome. This is possibly related to the similar size and level of complexity of the genomes of both of these species.</p> / Master of Science (MSc)
24

Meckelin Functions in the Guided Movement and Orientation of Basal Bodies Prior to Duplication in Paramecium tetraurelia

Picariello, Tyler August 01 January 2015 (has links)
Ciliopathies are a group of disorders that arise from ciliary dysfunction. Meckelin (MKS3 or TMEM67) is a conserved transmembrane protein found at the transition zone of ciliated cells. In humans MKS3 is one of 3 genes linked to the ciliopathy Meckel Syndrome. This disease is characterized by occipital meningioencephalocoele, polycystic kidneys, fibrotic changes to the liver, postnatal polydactyly and situs inversus. Paramecium tetraurelia is a single celled ciliated eukaryote. Its surface is organized of a meshwork of cortical units that run the length of the cell. At the center of the cortical units are either one or two basal bodies. In two basal body units only the posterior basal body is ciliated. From the ciliated basal body, three rootlets project in stereotypical orientations: the post-ciliary rootlet projects posteriorly, the transverse microtubule projects toward the adjacent basal body row and the striated rootlet projects anteriorly. Both the post-ciliary rootlet and transverse microtubule are microtubule-based structures. The striated rootlet is composed of multiple subunits that are predicted to have conserved segmented coiled coil domains known as SF-Assemblin domains. In Picariello at al., 2014, we showed that MKS3 is present in the transition zone of Paramecium tetraurelia and that RNAi for MKS3 leads to global ciliary loss. Additionally, RNAi for MKS3 results in the disorganization of the basal body rows. Within the areas of disorganization, the basal bodies along with their striated rootlets, post-ciliary rootlets and transverse microtubules are rotated away from their expected orientation. Interestingly, the post-ciliary rootlet and transverse microtubule are still attached at the expected angles relative to each other within the areas of disorganization. Initial GST pull-down experiments using the coiled coil domain of MKS3 suggest a potential interaction between MKS3 and the striated rootlet family members KdC1 and KdB2. To test potential interactions between MKS3 and the striated rootlet we identified 27 potential striated rootlet family members in Paramecium. Full-length sequences for 13 of these genes were marked at their N-terminus with a 3x FLAG sequence. Components with a conserved SF-Assemblin domain were distributed uniformly within the striated rootlet. Components lacking the SF-Assemblin domain were found in various cellular locations, but not within the striated rootlet. GST pull-down experiments utilizing the MKS3 C-terminus as bait were performed using cells expressing the FLAG-tagged striated rootlet family members. Unfortunately a clear interaction between MKS3 and the striated rootlet remains elusive. The organized nature of the surface of Paramecium has allowed us to identify a previously unrealized function for MKS3. Our immunofluorescence data suggest that MKS3 functions outside the transition zone to maintain basal body row organization by potentially contributing to a link between the basal body and the striated rootlet. Without the link, the migrating basal bodies are free to rotate and project their rootlets in the wrong directions. Although the nature of the link remains elusive, the identification of disorganized basal body rows upon MKS3 reduction suggests that, in addition to ciliary dysfunction, basal body polarity defects may contribute to the development of MKS.
25

Multi-Species Gene Networks and Drosophila Ethanol Sedation

Kollah, Arnavaz 01 January 2014 (has links)
Alcohol use disorders (AUDs) are major health issues with few known genetic explanations. This project used the fruit fly (Drosophila melanogaster) model to identify genes and gene networks that influence alcohol intoxication, a phenotype related to alcohol abuse in humans. We used bioinformatic tools to build gene networks based on 24 published Drosophila ethanol-responsive genes with human orthologs. We then assessed the role of these networks in ethanol sedation by testing two of the networks seeded on IP3K2, a gene that regulates calcium signaling, and CG14630, a gene involved in carnitine biosynthesis. We knocked down several genes in each of the networks using RNAi and tested the knockdown flies in a behavioral assay for ethanol sedation. Nervous system RNAi expression against 7 of 20 genes in the IP3K2 network and 4 of 30 genes in the CG14630 network significantly affected the sensitivity of flies to ethanol. To determine whether the hit rates in these two networks were greater than would be expected by random chance alone, we also assessed the effects of nervous system RNAi targeting a random set of fly genes. Unexpectedly, the fraction of randomly selected genes that affected ethanol sensitivity in a primary screen was comparable to or even larger than that from bioinformatically-derived gene networks. Our data are consistent with two possibilities that are not mutually exclusive. One possibility is that there are a very large number of genes that impact ethanol sedation and our bioinformatic analyses did not substantially enrich for these genes. A second possibility is that expression of RNAi could influence ethanol sedation independent of target gene knock-down. These two possibilities will be examined in future experiments.
26

Investigating the Role of the Synaptic Transcriptome in Ethanol-Responsive Behaviors

O'Brien, Megan A 01 January 2014 (has links)
Alcoholism is a complex neurological disorder characterized by loss of control in limiting intake, compulsion to seek and imbibe ethanol, and chronic craving and relapse. It is suggested that the characteristic behaviors associated with the escalation of drug use are caused by long-term molecular adaptations precipitated by the drug’s continual administration. These lasting activity-dependent changes that underlie addiction-associated behavior are thought, in part, to depend on new protein synthesis and remodeling at the synapses. It is well established that mRNA can be transported to neuronal distal processes, where it can undergo localized translation that is regulated in a spatially restricted manner in response to stimulation. Through two avenues of investigation, the research herein demonstrates that behavioral responses to ethanol result, at least in part, from alterations in the synaptic transcriptome which contribute to synaptic remodeling and plasticity. The synaptoneurosome preparation was utilized to enrich for RNAs trafficked to the synapse. Two complementary methods of genomic profiling, microarrays and RNA-Seq, were used to survey the synaptic transcriptome of DBA/2J mice subjected to ethanol-induced behavioral sensitization. A habituating expression profile, characteristic of glucocorticoid-responsive genes, was observed for a portion of synaptically targeted genes determined to be sensitive to repeated ethanol exposure. Other ethanol-responsive genes significantly enriched for at the synapse were related to biological functions such as protein folding and extra-cellular matrix components, suggesting a role for local regulation of synaptic functioning by ethanol. In a separate series of experiments, it was shown that altered trafficking of Bdnf, an ethanol-responsive gene, resulted in aberrant ethanol behavioral phenotypes. In particular, mice lacking dendritically targeted Bdnf mRNA exhibited enhanced sensitivity to low, activating doses and high, sedating doses of ethanol. Together these experiments suggest that ethanol has local regulatory effects at the synapse and lays the foundation for further investigations into the role of the synaptic transcriptome in ethanol-responsive behaviors. Supported by NIAA grants R01AA014717, U01 AA016667 and P20AA017828 to MFM, F31AA021035 to MAO, and NIDA T32DA007027 to WLD.
27

Genetic association analysis incorporating intermediate phenotypes information for complex diseases

Li, Yafang 01 December 2011 (has links)
Genome-wide association (GWA) studies have been successfully applied in detection of susceptibility loci for complex diseases, but most of the identified variants have a large to moderate effect, and explain only a limited proportion of the heritability of the diseases. It is believed that the majority of the latent risk alleles have very small risk effects that are difficult to be identified and GWA study may have inadequate power in dealing with those small effect variants. Researchers will often collect other phenotypic information in addition to disease status to maximize the output from the study. Some of the phenotypes can be on the pathway to the disease, i.e., intermediate phenotype. Statistical methods based on both the disease status and intermediate phenotype should be more powerful than a case-control study as it incorporates more information. Meta-analysis has been used in genetic association analysis for many years to combine information from multiple populations, but never been used in a single population GWA study. In this study, simulations were conducted and the results show that when an intermediate phenotype is available, the meta-analysis incorporating the disease status and intermediate phenotype information from a single population has more power than a case-control study only in GWA study of complex diseases, especially for identification of those loci that have a very small effect. And compared with Fisher's method, the modified inverse variance weighted meta-analysis method is more robust as it is more powerful and has a lower type I error rate at the same time, which provides a potent approach in detecting the susceptibility loci associated with complex diseases, especially for those latent loci whose effect are very small. In the meta-analysis of lung cancer with smoking data, the results replicate the signal in \emph{CHRNA3} and \emph{CHRNA5} genes on chromosome 15q25. Some new signals in \emph{CYP2F1} on chromosome 19, \emph{SUMF1} on chromosome 3, and \emph{ARHGAP10} on chromosome 4 are also detected. And the \emph{CYP2F1} gene, close to the already known cigarette-induced lung cancer gene \emph{CYP2A6}, is highly possible another cytochrome P450 (CYP) gene that is related to the smoking-involved lung cancer. The meta-analysis of rheumatoid arthritis with anti-cyclic citrullinated peptide (anti-CCP) data identified new signals on 9q24 and 16q12. There are evidences these two regions are involved in other autoimmune diseases and different autoimmune/inflammatory diseases may share same genetic susceptibility loci. Both the theoretical and empirical studies show that the modified variance weighted meta-analysis method is a robust method and is a potent approach in detecting the susceptibility loci associated with complex diseases when an intermediate phenotype is available.
28

Sequence Extension of the Tryptophan and Shikimate Operons in Clostridium Scatologenes ATCC 25775

Smiley, Shawn Johnston 01 October 2017 (has links)
3-Methylindole and 4-methylphenol are cytotoxic and malodorant compounds derived from tryptophan and tyrosine, respectively. Each is present in swine waste lagoons and contributes to malodorous emissions from agricultural facilities. Clostridium scatologenes ATCC 25775 produces both compounds and serves as a model organism to study their metabolism and function. Through the repeated assembly and annotation of the Clostridium scatologenes genome, we propose a novel pathway for tryptophan degradation and 3-methylindole production by this organism. The genome of Clostridium scatologenes was sequenced, and re-assembled into contigs. Key elements of the tryptophan and shikimate pathways were identified. Contigs containing these elements were extracted from assemblies and matched to the reference genome of Clostridium carboxidivorans. Sequence for both pathways was then extended and defined using these joined sequence fragments. This sequence could serve as a starting point for the isolation of genes related to 3-methylindole synthesis using biochemical and enzyme analysis
29

Transcriptomic Response to Immune Challenge in Zebra Finch (Taeniopygia Guttata) Using RNA-SEQ

Scalf, Cassandra 01 April 2018 (has links)
Despite the convergence of rapid technological advances in genomics and the maturing field of ecoimmunology, our understanding of the genes that regulate immunity in wild populations is still nascent. Previous work to assess immune function has relied upon relatively crude measures of immunocompetence. However, with next-generation RNA-sequencing, it is now possible to create a profile of gene expression in response to an immune challenge. In this study, captive zebra finch (Taeniopygia guttata; adult males) were challenged with bacterial lipopolysaccharide (2 mg/Kg BW; dissolved in 0.9% saline) or vehicle (0.9% saline) to stimulate the immune system. Two hours after injection, birds were euthanized and hypothalami, spleen, and red blood cells (RBCs) were collected. Taking advantage of the fully sequenced genome of zebra finch, total RNA was isolated, sequenced, and partially annotated in these tissue/cells. The data show 628 significantly upregulated transcripts in the hypothalamus, as well as 439 and 121 in the spleen and RBCs, respectively, relative to controls. Also, 134 transcripts in the hypothalamus, 517 in the spleen, and 61 in the RBCs were significantly downregulated. More specifically, a number of immunity-related transcripts (e.g., IL-1β, RSAD2, SOCS3) were upregulated among tissues/cells. Additionally, transcripts involved in metabolic processes (APOD, LRAT, RBP4) were downregulated, suggesting a potential trade-off in expression of genes that regulate immunity and metabolism. Unlike mammals, birds have nucleated RBCs, and these results suggest a novel transcriptomic response of RBCs to immune challenge. Lastly, molecular biomarkers could be developed to rapidly screen bird populations by simple blood sampling in the field.
30

Molecular cloning of spinach chloroplast DNA isolated by alkaline lysis

Drager, Robert Gray 01 January 1987 (has links)
Chloroplast genomes of land plants show conservation of structure and gene arrangement. The spinach chloroplast genome is comprised of a covalently closed. circular DNA molecule of 150 kilobases and is typical of these plants. Approximately 20% of the proteins found in the spinach chloroplast are encoded by the chloroplast genome and translated on chloroplast ribosomes. The remainder are encoded on chromosomes in the nucleus, translated on cytoplasmic ribosomes and transported into the chloroplast. Spinach chloroplast DNA was isolated from crude 2 chloroplast preparations by a new method. Chloroplasts were lysed with alkaline sodium dodecyl sulfate, contaminating macromolecules precipitated with acidified potassium acetate and plastid DNA was purified by phenol:chloroform extraction and ethanol:ammonium acetate precipitation. The yield was approximately 50 ug chloroplast DNA per 100 grams leaf material. The DNA consisted of 10% circular molecules and 90% linear molecules. The chloroplast DNA was digested with restriction enzyme PstI and the fragments were cloned into the plasmid vector pUC9. Several recombinant plasmids were isolated and the chloroplast DNA inserts identified. The recombinant plasmid pRD105 containing the PstI #5 fragment was subjected to further investigation. The ClaI restriction sites of the PstI #5 fragment were mapped and the insert was subcloned into the plasmid vector pGEM4, which bears bacteriophage SP6 and T7 RNA polymerase promoter sequences.

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