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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

Induction of pathogenesis-related genes, PR-17a and N-methyltransferase, in barley infested by the aphid Rhopalosiphum padi

Grönberg, Naima January 2006 (has links)
Plants produce a large diverse array of organic compounds that may function in protection against pathogens. Diverse antifungal compounds were reported to exist in barley (Hordeum vulgare L.); the indole alkaloid, gramine, and the pathogenesis-related proteins are some of them. Both the N-methyltransferase that is involved in gramine biosynthesis and PR-17a were studied in barley upon infestation by the bird cherry-oat aphid (Rhopalosiphum padi). The effect of infestation by R. padi on induction of PR-17a and N-methyltransferase was investigated in different barley lines, susceptible and resistant. The gene expression of PR-17a was down-regulated in the susceptible cv. Golf and to some extent up-regulated at the first days in var. Lina and then down-regulated. The PR-17a was induced by the aphid infestation in the resistant line CI16145; the gene expression was stronger in the infested plants than in the controls. The different responses in resistant and susceptible lines indicate that the induced PR-17a may play a role in the resistance against aphid infestation. PR-17a was up-regulated systemically in the base in barley after infestation by R. padi. In the susceptible varieties Lina and Golf, the accumulation of N-methyltransferase did not increase with time from 1 day to 7 days after infestation, as determined by western blots with antibody raised against NMT from barley. The NMT-gene was down-regulated after 7 days infestation in both variety Lina and Golf both locally in the first leaf and in the base. Barley line CI16145 had no accumulation of NMT as was seen by western blotting. There was no induction of NMT in barley upon aphid infestation.
22

Expression and Purification of Full-length CYP26 B1 and Spliced CYP26 B1

Sundin, Johanna January 2009 (has links)
The goal of this project is to express both the normal CYP26 B1 and the spliced CYP26 B1 from human in Escherichia coli (E.coli) cells for further crystallization. This will be achieved by cloning in the DNA fragments into the Champion pET SUMO vector that is later transformed into E.coli cells. The CYP26 B1 contains a hydrophobic helix at the N-terminal of the protein, making both protein expression and crystallization difficult. Two variants of both full-length CYP26 B1 and the spliced variant will therefore be made, one with the trans-membrane helix present and one without the helix. The SUMO-vector will produce a fusion protein that will make CYP26 B1 more hydrophilic and improve the purification of the two proteins.
23

Embryonic Gene Alterations in rats Caused by Exposure to Diabetes and/or Obesity

Ehtesham, Ehtesham January 2012 (has links)
There is ample evidence that both diabetes as well as obesity leads to various metabolic disturbances that leads to oxidative stress. Oxidative stress has been shown  to  be  associated  with  congenital  malformations  of  which  neural  tube defects  and  cardiac  malformations  are  more  common.  The  cellular  and molecular  mechanisms  through  which  oxidative  stress  induces  these  defects during the developmental stage are not well known. Previous work in this field suggests   that   oxidative   stress   results   in   lipid   peroxidation   and   altered expression  of  genes  that  have  key  roles  in  the  developmental  processes.  The present study aimed to investigate gene alterations in embryos from pregnant diabetic  or  obese  rats.  Embryos  and  adipose  tissue  obtained  from  the  locally bred  diabetic  and  obese  Sprague-Dawley  inbred  rat  strain  were  subjected  to Total  RNA  extraction  and  were  quantified  using  Real  time  PCR  for  relative gene expressions analysis. The present study showed that maternal diabetes as well  as  obesity  diminishes  the  antioxidative  defense  mechanisms  by  down regulating the gene expressions of the key reactive oxygen species scavenging enzymes   copper   zinc   superoxide   dismutase   and   manganese   superoxide dismutase  in  day  10  rat  embryos.  There  was  also  altered  embryonic  gene expression  for  several  developmental  genes  due  to  maternal  diabetes  at gestational day 11 and 13 in rat embryos.
24

Studies of recombinant forms of Aleuria aurantia lectin

Olausson, Johan January 2009 (has links)
The presented work describes construction and analysis of recombinantly produced forms of Aleuria aurantia lectin (AAL). The binding properties of the produced AAL forms were studied using techniques such as tryptophan fluorescence, hemagglutination analysis, ELISA and surface plasmon resonance analysis. Lectins are proteins that are ubiquitous in nature with the ability to bind specifically to different types of carbohydrates. The physiological function of different lectins is not always known, but they are involved in many recognition events at molecular and cellular levels. In research, lectins are widely used for structural and functional studies of complex carbohydrates, and they are also used to detect changes in the carbohydrate pattern on glycoproteins in different diseases. With the use of recombinant technology it is now possible to refine properties of lectins such as decreasing the valency and alter specificity and affinity. This may be a way of constructing more suitable reagents for use in diagnostic glycosylation analysis assays. AAL has been extensively used in different types of research for its ability to bind the monosaccharide fucose and to fucose-containing oligosaccharides. It is composed of two identical subunits where each subunit contains five binding sites for fucose. AAL was expressed recombinantly (rAAL) and its properties was investigated. These studies reveled that one of the binding sites in rAAL had unusually high affinities towards fucose and fucosecontaining oligosaccharides with Kd-values in the nanomolar range. This binding site is not detected in AAL that have been exposed to fucose during its purification, and therefore we proposed that this site may be blocked with free fucose in commercial preparations of AAL. Normally lectin-oligosaccharide interactions are considered to be of weak affinity, so the finding of a high affinity site was interesting for the future study of recombinant forms of AAL. The next step was to produce recombinant AAL forms with decreased valency. This was done using site-directed mutagenesis. First a monomeric form of AAL (mAAL) was constructed and then a monovalent form of AAL, containing only one fucose-binding site (S2-AAL) was constructed. Both of these forms had retained ability to bind fucose. The binding characteristics of mAAL were similar to that of rAAL, but mAAL showed decreased hemagglutinating activity. S2-AAL showed a lower binding affinity to fucosylated oligosaccharides and did not bind to sialylated fuco-oligosaccharides such as sialyl-LewisX. This study shows that molecular engineering techniques could be important tools for development of reliable and specific diagnostic and biological assays for carbohydrate analysis.
25

Purification, functional characterization and crystallization of the MntR manganese sensor from Saccharopolyspora erythraea

Svensson, Malin January 2020 (has links)
No description available.
26

Mapping the encoding of innate versus learned aversive threat in the amygdala.

Das Barman, Shubhangi January 2021 (has links)
The amygdala is essential in the process of learned aversive signals. Its implication in processing an innately aversive threat remains to be decoded. This implies asking questions on how a learned and an innate aversive threat is processed. Learned aversive threat involves changes in synaptic plasticity while the responses to the innate aversive threat are hard-wired in the animal’s brain. A way to answer this question is to visualize the neurons activated by both behaviors in the same animal. To do so, a set of behavioral experiments were done with the help of a cross of Rosa td Tomato and TRAP2-Cre mice in combination with c-Fos staining. Following this, a combination of techniques including behavioral studies, immunohistochemistry and apotome microscopy for cell quantification were being used. This was intended to find the number of TRAP cells and c-Fos cells in the areas of LA, BA, CeL and CeM respectively. A heat map was further being plotted to measure the density of the cells in each area. The percentage of cells which got activated when a specific stimulus was being repeated twice were also being quantified using the Fiji software. The results section discusses the analysis of shock-shock and loom-loom experiments wherein the freezing percentages of the first set of mice (aversive threat measurement experiments) and the looming behavior of the second set of mice were being analyzed. It was observed that the freezing rate of all the mice used for the aversive threat measurement experiments increased steadily with time. The responses of the mice to the looming stimulus were also significant. The quantification of the number of cells which got activated when the mice were exposed to the shock stimulus twice indicated that Lateral amygdala (50%) exhibited the maximum percentage of cells in the case of shock-shock experiments and the central amygdala in the case of loom-loom experiments (30-50%). This helped us to identify some of the primary areas involved when the mice were being exposed to a shock or loom stimulus. It also helped us to infer the percentage of cells which got activated when the same stimulus was being repeated twice. These experiments serve as a foundation for the future experiments to learn about the specific cell types involved in each area and whether these cell populations get activated when the same stimulus is being repeated twice.
27

Assessment of methods for microRNA isolation, microRNA amplification, and development of a normalization strategy for sepsis biomarker research

Nordén, Johan January 2020 (has links)
Sepsis, defined by organ dysfunction caused by an adverse immune response of the host to an infection, comes with considerable cost in human lives and as a substantial burden financially. Significant upgrades have been made over the past two decades when diagnosing and treating sepsis but still with room for improvements. Early detection is a cornerstone in the fight against sepsis, and the focus on strengthening diagnostics is in the forefront of modern research. The implementation of biomarkers may be the path of progression in this objective. This study aimed at establishing procedural foundations when using microRNAs as potential biomarkers. The study conducted looked at: (1) Isolation procedure, of microRNA from human plasma, of three kits: Total RNA Purification Kit (Norgen Biotech), miRNAeasy Serum/Plasma Kit (Qiagen), and miRNeasy Serum/Plasma Advanced Kit (Qiagen). (2) Amplification of miRNA through two Reverse Transcription Quantitative PCR methods: Two-tailed RT-qPCR (TATAA Biocenter), and miRCURY LNA miRNA PCR (Qiagen). (3) Developing a normalization strategy by identifying miRNA reference targets in a geNorm pilot experiment. Qubit analysis revealed that the two isolation kits from Qiagen performed similar, and better that the Norgen kit. The Two-tailed RT-qPCR failed to amplify miRNA samples, whereas the miRCURY LNA miRNA PCR showed consistent amplification across samples with a high call rate. The geNorm analysis concluded that hsa-miR-425-5p and hsa-miR-93-5p was the optimal reference target set. The study demonstrated that the isolation kits from Qiagen coupled with the miRCURY LNA miRNA PCR is a viable option for future miRNA biomarker studies.
28

Detection and Characterization Of pancreatic cancer exosome using ExoPLA

Kalukhe, Himangi January 2021 (has links)
No description available.
29

Intermittent fasting’s impact on autophagy, insulin sensitivity and cortisol in a clinical setting : A Systematic Review

Otter, Marcus, Laag, Anton January 2022 (has links)
No description available.
30

Understanding endothelial cell distribution in Cerebral Cavernous Malformations

Desai, Malavika Bimal January 2021 (has links)
No description available.

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