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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.
461

The fertile ovary transcriptome and proteome

Östman, Josephine January 2021 (has links)
The Human Protein Atlas is an open-source database containing information about protein expression and location in the human cells,tissues and organs. The aim is to map all the proteins in humans using various biotechnology techniques such as antibody-based imaging, andRNA sequencing etc. Based on previous transcriptome analysis, 173 genes were shown to have an elevated expression in ovary compared to all other major tissue types in the human body. There is however no information regarding the expression in ovary during the reproductive years versus the post-menopausal years. In this thesis, the gene expression in ovaries of women in reproductive age was compared with women in post-menopausal age. 509 genes were found to have an at least 2-fold higher mean value RNA expression in the reproductive age group. 14 of these genes were analyzed further with antibody staining and multiplex immunofluorescence staining to localize the corresponding proteins. The results show that these genes are expressed in a variety of structures in the ovarian tissue, such as the oocyte, the granulosa cells and the corpus luteum. This thesis has demonstrated how data analysis can be used to find genes important for the ovary of women in reproductive age and in the future, this could aid research in female fertility.
462

Statuserhebung Genetische Diversität Schwein

Brockmann, Gudrun A., Müller, Uwe, Schmidt, Armin O., Distl, Ottmar, Bergfeld, Uwe, Müller, Ulf 07 May 2012 (has links)
Die hier präsentierten Ergebnisse stellen erstmals genomweite Untersuchungen zur Deutschen Landrasse vor. Basis für die Assoziationsstudie waren 288 ausgewählte Eber, welche mit dem 60K BeadChip der Firma Illumina typisiert wurden. Die Untersuchungen zur genetischen Diversität zeigen, dass die Population eine sehr gute Vielfältigkeit an segregierenden Allelen aufweist. Für die Lebenstagszunahme, die Fettfläche und den pH-Wert zeigten sowohl die SNPs als auch die Haplotypen einen engen Bezug zur Merkmalsausprägung.
463

Aktivt deltagande i undervisning i genetik

Croes, Tamara January 2020 (has links)
Studien har som syfte att hitta beprövade och fungerande metoder för att höja aktivt deltagande i undervisning i genetik på gymnasieskolan. Aktivt deltagande ses av många forskare som en förutsättning för att lära sig någonting. Studien består av enkäter för gymnasieelever i biologi och personliga intervjuer med biologilärare och andra professionella personer inom undervisning. Studien grundar sig i det sociokulturella perspektivet, som baserar sig på Vygotskijs teori att allt lärande sker i sociala sammanhang, samt på Dewey’s “learning by doing”. Resultatet stämmer väl överens med tidigare forskning. Metoderna som både elever och pedagogerna uppskattade mest var att relatera undervisningen till elevernas egna erfarenheter, till aktuella situationer (såsom coronavirus), att utveckla bra personliga relationer till elever, och att variera undervisningen. Vad som också verkar fungera relativt bra är EPA (Enstaka, Par, Alla) och självständig forskning. Eleverna hade inte alltid samma uppfattning som pedagoger över vad som motiverade dem, till exempel om vikten av att aktiviteter är relaterade till deras egna erfarenheter och intressen, och det kan vara värt att undersöka vidare i framtida forskning. Studien avslutas med en antal rekommendationer till lärare, av vilka de flesta är användbara även i annan undervisning än just i genetik.
464

A spatial analysis of Norwegian spruce cone developmental stages

Orozco, Alina January 2020 (has links)
The Norway spruce Picea abies is an economically important export to the Swedish economy. There are a number of environmental and endogenous factors that impact the generation time of this species meaning that it can take 20-25 years for a tree to mature. The long generation time creates a challenge for plant breeding programs in terms of how genetic mechanisms are able to be studied as well as how quickly trees can be produced for lumber. The characterization of gene expression patterns in the context of special tissue domains is essential to understanding the underlying functions behind complex biological systems and in the case of P. abies may prove more crucial to determining the activation of genes at specific reproductive growth points. There are several techniques available for the analysis of spatial expression profiles, however, the unique high throughput nature coupled to the morphological information provided by Spatial Transcriptomics creates new opportunities for exploratory analysis. Spatial Transcriptomics offers a distinct approach to answering fundamental questions about the genetic mechanisms that regulate reproductive phase change and cone-setting in conifers. This study focuses on spatial gene expression analysis and the integration of de novo transcriptome assembly contigs to confirm the spatial context of putatively discovered genes such as DAL1, DAL2, DAL3, and DAL10 from previous studies and to potentially localize transcripts that could not previously be identified due to the inability to obtain complete transcripts. The aim is to create a workflow to identify genes that contribute to the growth patterns in the naturally occurring acrocona mutant that could prove useful to improving tree breeding programs.
465

Molekularbiologische Untersuchungen verschiedener Komponenten des Glucose-Phosphotransferasesystems in Escherichia coli K-12 mit Schwerpunkt auf der Strukturanalyse des Transportproteins EIICBGlc

Gabor, Elisabeth 19 October 2011 (has links)
Es wurde ein System zur chemischen Modifizierung von Einzelcysteinvarianten des PTS- Transporters EIICBGlc etabliert, mit dem durch unterschiedliche Zugänglichkeit von Markersubstanzen die Zuordnung der jeweiligen Cysteine in Hinblick auf die Cytoplasmamembran gelang. Für die Methode war es notwendig, eine cysteinfreies EIICBGlc zu konstruieren. Dieses trägt des Weiteren eine Mutation, die die Phosphorylierung des Substrats Glukose von dem Transport entkoppelt. Dies ist notwendig, da das Cystein 421, das für die Phosphorylierung des WT verantwortlich ist, in dem cysteinfreien Protein nicht mehr vorhanden ist. Die Transportfähigkeit der Mutanten konnte nachgewiesen werden. Die Ergebnisse des Cystein-Scannings, Daten über dieses Protein aus vorangegangenen Arbeiten, sowie ein Vergleich der Struktur des EIIChb aus B. cereus, ermöglichten die Erstellung eines neuen Modells des Proteins EIICBGlc. In diesem Modell enthält das Protein 10 transmembrane Helices. Die postulierte Substratbindetasche wird aus haarnadelartigen Strukturen gebildet. Die Lage funktioneller Mutanten in dem Modell wurde diskutiert. Die entkoppelte Mutation R203H des Proteins EIICBGlc wurde isoliert. Eine Charakterisierung in Bezug auf ihre Fähigkeit Mlc zu titrieren, zeigte, dass eine Bindung von Mlc in diesem Protein möglich ist. Eine Konformationsänderung, die die Wechselwirkung zu Mlc inhibiert, liegt daher in diesem Protein nicht vor. Es wurde außerdem gezeigt, dass keine Erweiterung der Substratspezifität in diesem Protein vorliegt.
466

Biotransformation of fusidic acid and its related derivatives by Streptomyces lividans

Biukovic, Goran 30 March 2005 (has links)
As shown in previous studies Streptomyces lividans enzymatically inactivates fusidic acid by specific esterase FusH giving rise to the 16ß-OH derivative, which sponaneously converts to the lactone.in this work it was shown that S. lividans further modifies fusidic acid and both derivatives, which resulted in several new related substances. The two intermediates (La, Lb) were isolated from the culture filtrate of S. lividans, which was grown in the presence of fusidic acid. The differences in their chemical structures indicate the involvement of multiple enzyme reactions related to hydroxylation, hydration, dehydrogenation and isomerization. Several enzymes were identified and two of them (FusG, FusB) were partially characterized. According to their characteristics and the structures of isolated intermediates, the identified enzymes which are involved in biotranformation are conceivably related to the ones implicated in ß oxidation. The biotransformation of fusidic acid and its derivatives by S. lividans is so far unique, since characterized substances La and Lb have not been found in either fusidic acid-producing or fusidic acid-resistant microorganisms.
467

Studies on the essential YNL152w open reading frame in Saccharomyces cerevisiae

Ciklic, Ivan 29 June 2007 (has links)
The essential gene YNL152w was previously found in a screen designed to isolate putative negative regulators of the S. cerevisiae Pkc1p pathway. Activity assays were performed with a lexA-RLM1-lacZ integrated reporter in different ynl152w truncated mutants. In contrast to the original screen, there were no differences or the activities were even lower in some mutants. To analyze the consequences of different expression levels, YNL152w was expressed under the control of the GAL1/10 promoter. Growth curves were performed under high, intermediate and low expression levels. Strikingly, both conditional strains were able to grow under repressing conditions. However, an aberrant morphology was found suggesting that the cells are indeed affected by low amounts of Ynl152w protein. A series of successive Ynl152wp C-terminal truncations was analyzed to determine cell viability and to investigate the function of the protein. Remarkably, about 2/3 of the protein were dispensable to confer viability. Microscopic analyses of constructs revealed an aberrant morphology characteristic of a cytokinesis defective mutant, with the appearance of swollen cells and formation of big aggregates. Interestingly, the phenotype was more pronounced in the larger truncations. Coherent with these results time-lapse experiments with a large truncated mutant showed a stabilization of the SH3 protein Hof1p at the bud neck. This protein is involved in septum formation and has been reported as a binding partner of YNL152w. The phenotypes observed in the truncated mutants could be attributed to the presence of 4 proline rich motifs. Such motifs have been reported to interact with SH3 domains. An internal deletion of an aspartate rich domain present in the Ynl152wp sequence also displayed a phenotype very similar to that of the largest truncations. Therefore, this domain may play an important role in Ynl152wp function.
468

Crosstalk between glucose and cell integrity signaling pathways in Saccharomyces cerevisiae

Backhaus, Katja 17 April 2013 (has links)
The yeast cell wall confers shape and integrity and serves as a first barrier against adverse environmental conditions. This thesis provides a first analysis of the cell wall structure of the milk yeast Kluyveromyces lactis and compares it to the one of the baker’s yeast Saccharomyces cerevisiae. Transmission electron microscopy revealed that the cell wall of K. lactis is 60 nm thick in glucose-grown cells and increases to 100 nm on ethanol media, whereas S. cerevisiae displays a cell wall thickness of 100 nm under both conditions. The cell wall proteome of K. lactis shares several homologs with the one of S. cerevisiae, but also contains three proteins not found in the latter. Moreover, three of the common cell wall proteins have two isoforms in K. lactis, but only one in S. cerevisiae. The restructuring of the cell wall on different carbon sources (i.e. glucose versus ethanol) indicates a relation between cell wall synthesis and/or remodeling and glucose signaling. Therefore, a key regulator which mediates the glucose response in S. cerevisiae, the SNF1 protein kinase complex, was further investigated. Mutants lacking the kinase activity have a thinner cell wall and show pronounced cell wall phenotypes in S. cerevisiae, i.e. they are hypersensitive to Zymolyase, Congo red, Calcofluor white and to the antifungal agent Caspofungin. Epistasis analyses with mutants affecting cell wall integrity signaling indicate that the SNF1 complex acts in parallel to the CWI pathway, which is induced upon cell wall stress. Immunological detection reveals the phosphorylation of Thr210 in the Snf1 kinase subunit, which is an indication for the activation of the kinase complex. Genetic analyses suggest that the transcriptional repressor Mig1 may be a downstream target mediating the cellular response. Further epistasis analyses with glycolytic mutants indicate that the availability of glucose-6-phosphate influences the cell wall phenotype of snf1Δ mutants. Hence, the role of the SNF1 complex in cell wall integrity is related to the glucose metabolism and glycolytic flux. This work provides the first comprehensive analysis of the role of glucose signaling and the SNF1 complex in yeast cell wall biosynthesis.
469

Conservation Genomics of the Long-tailed Duck

Magnúsdóttir, Brynhildur January 2021 (has links)
With increasingly warming climate, many bird species have been forced to respond to environmental changes, and the long-tailed duck (Clangula hyemalis) is no exception. The populations of the long-tailed duck have been in decline the past few decades and the species is classified as globally vulnerable and near threatened in both Iceland and Sweden. The long-tailed duck is a circumpolar, migratory sea duck. Its migratory routes and wintering and breeding sites might play an important part in gene flow between populations. The aim of this project was to get a clearer image of the substructure of the long-tailed duck in the northern hemisphere to help identify populations possibly at risk. This was investigated by exploring differences in mitochondrial DNA between the global populations, and by studying the Icelandic wintering and breeding populations in particular applying whole genome sequencing. To do this, samples were obtained for mitochondrial DNA analyses from a previous study by Wilson et al. (2016) from North America and East Russia, samples from other populations around the northern hemisphere as well and new samples from Iceland. Museum samples from Iceland were used for whole genome resequencing. Mitochondrial analyses included haplotype identification, population comparisons, mismatch and neutrality tests. Whole genome analyses included neutrality tests, principal component analysis and genetic admixture analysis.The mitochondrial results revealed two distinct lineages for the long-tailed duck. Two populations showed a difference from the other populations; the Icelandic breeding population and the Yukon-Kuskokwim Delta population from Alaska, which are the southernmost breeding populations. The Yukon population might have been previously isolated with refugial population intermixing. For the Icelandic populations, the mitochondrial results showed little intermixing between the winter and breeding populations. The whole genome results showed more complicated results for the Icelandic populations, with admixture in some individuals. This suggests that there seems to be more variation in the genome than implied by the mitochondrial DNA.
470

Genome-wide association studies on body weight and component traits in an intercross of two divergently selected chicken lines

Chen, Yiwen January 2021 (has links)
Here we present the genome-wide association study of body weight at 8 weeks of age based onthe advanced intercross pedigree of two chicken lines gone through bi-directional selection.With improved marker density (~3M SNPs) and larger sample size (2667 individuals from F2-F15), 34 loci with suggestive significance are detected, of which 18 loci are novel, and the rest17 loci are consistent with the results of previous quantitative trait locus mapping studies onthis trait with smaller number of genetic markers and fewer individuals. The component traits,referring to traits related to body weight and possibly contributing to the body weight as well,are also measured and analysed. The combined result showed that one locus with significantmarginal effect on BW8 is associated with early growth, breast muscle development and shankdevelopment, while another locus with late development and bursa development.

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