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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.
81

Příprava a charakterizace antipeptidových protilátek pro imunodetekci cytochromů P450 / Preparation and characterization of antipeptide antibodies for immunodetection of cytochromes P450

Mácová, Iva January 2013 (has links)
The cytochromes P450 are enzymes participating in metabolism of endogenous and exogenous compounds. Their substrates include also carcinogens which may initiate carcinogenesis after activation by CYP450. Inductors of these enzymes are also chemopreventive compounds which are very popular and recommended in current time. Thus, studying of the effect of the chemopreventive compounds on cytochromes P450 induction and cancer development is of a high clinical importance. The CYPs are most commonly found in the liver. However, there are forms that have not been detected in any human healthy tissue but their overexpression was observed in tumors. For this reason, they could serve for diagnosis and prognosis of cancer. Among these cytochromes are CYP2S1 and 2W1 which can be prognostic markers of colorectal cancer. Therefore, it would be opportune to have some tools for these enzyme detection. One option is immunodetection of cytochromes P450 by Western blot using the specific antibodies. Today mammalian antibodies (IgG) are the most widely used but antibodies isolated from egg yolk (IgY) become popular mainly due to the large number of undisputed advantages. For the preparation of the peptide immunogen, suitable peptide sequences were selected from CYP2S1 and 2W1 primary structure. The synthesized peptides...
82

MRI T2 Signal Changes Indicate Tau Pathophysiology in a Murine Alzheimer's Disease Model

Adhikari, Rajan Deep 01 August 2017 (has links)
Pathogenesis, diagnosis and treatment, the essential domains in medical practice, seem helpless to address Alzheimer's disease (AD). With a huge mortality rate, it is looming and threatening the socioeconomic barrier. Despite many different studies, the pathogenesis of AD remains inconclusive. However, growing numbers of studies suggest oxidative stress to contribute to the initiation and progression of AD. We propose an iron hypothesis: iron mediated oxidative damage by reactive oxygen species (ROS), which induces protective roles of amyloid beta and hyper-phosphorylated tau (HP-tau) to sequester iron and limit the disease. We propose to study such mechanism using transgenic mice models for AD, inducing oxidative stress to elevate intracellular iron, and analyze its co-localization with proteins using Magnetic Resonance Imaging (MRI), 1H Nuclear Magnetic Resonance (NMR) spectroscopy and Western blot. We report three primary findings: 1) a significant loss in T2 signal over bilateral hippocampi of transgenic mice compared to the wild types (WT) by three months, corresponding to early disease and the ability of proteins to sequestration iron. Ability of rescue treatments to impede disease progression reflected as preserved T2 signal intensities over these areas throughout our study period of nine months. 2) Concentration of zinc and its dual role in the presence or absence of oxidative stress reflected as loss of 1H NMR T2 measurement showed that higher concentrations of zinc were neuro protective when there was an active oxidative stress inducing condition, but neurotoxic and promote oxidative damage in normal condition. And 3) Different strains of mice, according to their transgene, expressed various proteins associated with AD. However, these expressions were in accordance with our iron-hypothesis.
83

Rye cell wall β-glucosidase: subcloning, expression and purification of recombinant protein from E.coli

Rochereau, Nicolas January 2007 (has links)
<p>Several plant defense systems consist of enzymes that act on glucosides and produce a toxic compound. In the intact plant tissue the substrate and enzyme are kept apart. The system studied here consists of the substrate 2-O-β-D-glucopyranosyl-4-dihydroxy-1,4-benzoxazin-3-one and the enzyme glucan 1,3-β-glucosidase in rye. The aim was to determine the properties of a cell wall β-glucosidase. Two different systems for expression and purification of β-glucosidase fused to a tag were used: a 6xHistidine tag system and a thioredoxin tag system. The sequence of the β-glucosidase had previously been determined so now the gene was subcloned into E.coli. A direct PCR on colonies, a test expression, a restriction digestion of plasmids and sequencing was made to analyze the transformation, which all turned out successful. Then the β-glucosidase solubility was determined. Finally a purification of the β-glucosidase from E.coli under native conditions and a pNPG assay was carried out. For the (His)6-tagged protein, the recombinant β-glucosidase tended to end up in the insoluble pelleted fraction which indicated formation of inclusion bodies. The cell wall 1,3-β-glucosidase was soluble with the thioredoxin system, but the percentage of soluble protein fraction was around 5% only of the total protein. In eluates from a nickel-nitrilotriacetic acid column the presence of recombinant protein was confirmed with Western blot, but contaminating bands were also present. Purified elauted fractions did not exhibit detectable β-glucosidase activity. It was not possible to purify active enzyme. From a BLAST search it was clear that the most similar enzymes all had putative glycosylation sites and lack of glycosylation could be a reason for the protein not to fold properly.</p>
84

Vascular endothelial growth factor in renal cell carcinoma

Jacobsen, Jan January 2006 (has links)
Background. Angiogenesis is essential for tumour growth. Vascular endothelial growth factor (VEGF) and its isoforms were investigated in relation to the clinical course in a large number of patients with renal cell carcinoma (RCC). Methods. RCC subtypes and behaviour were established by clinicopathological criteria and surveillance. VEGF expression was analysed in serum by enzyme-linked immuno-sorbent assay (ELISA) and in tumour tissue by reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), and Western blot (WB). Results. Serum VEGF (S-VEGF) was increased in RCC compared to control group. S-VEGF correlated with tumour stage and grade and was associated with survival in men but not in women. S-VEGF correlated with blood platelet counts, which were inversely correlated to increasing age in women, and they were decreased in chronically medicated patients, particularly in men. In contrast to S-VEGF, platelet counts associated with survival only in patients free of medication and chronic diseases. RT-PCR showed a correlation between VEGF121/VEGF165 mRNA and between VEGF165/VEGF-R1 mRNA. There was no association between different VEGF mRNA isoforms and S-VEGF. Conventional renal cell carcinoma (CRCC) had higher VEGF165, VEGF121, and VEGF-R1 mRNA levels compared with papillary renal cell carcinoma (PRCC). IHC VEGF staining was strong in kidney cortex. Kidney tumour showed a considerable variation in cytoplasmatic VEGF expression, which correlated with tumour size. Although, there was no difference in VEGF expression between the RCC types, VEGF expression was associated with survival only in CRCC. WB showed a strong protein expression of both VEGF189 and VEGF165 in kidney cortex. In kidney tumour, expression of VEGF189 varied the most, VEGF165 less so, and VEGF121 was rarely detected. Both CRCC and PRCC expressed low levels of VEGF189 and VEGF165 compared with kidney cortex. Chromophobe renal cell carcinoma (ChRCC) expressed VEGF189 levels comparable to those from kidney cortex, while VEGF165 was lower. In PRCC and ChRCC, VEGF189 levels correlated inversely with advancing tumour stage, and in PRCC, VEGF165 levels correlated inversely with increasing tumour size. VEGF189 was an independent prognostic factor for survival in patients with PRCC. Conclusions. S-VEGF has a stronger association to progression in RCC than platelet count. CRCC showed high levels of VEGF mRNA isoforms and VEGF-R1 mRNA compared to PRCC. VEGF mRNA isoforms expression decreased with advancing stage. IHC demonstrated VEGF expression in cell cytoplasm related to tumour growth, particular in CRCC. Different VEGF isoform patterns were found in different RCC types. Protein VEGF189 expression was associated with tumour stage and was an independent prognostic factor in PRCC. Protein VEGF165 expression was generally low and had no prognostic value. The trend for decreasing levels of VEGF isoforms in advanced tumour stages may indicate that angiogenic activity is an early event in tumour growth induced by VEGF, but that during later tumour progression the role of VEGF is less clear.
85

Rye cell wall β-glucosidase: subcloning, expression and purification of recombinant protein from E.coli

Rochereau, Nicolas January 2007 (has links)
Several plant defense systems consist of enzymes that act on glucosides and produce a toxic compound. In the intact plant tissue the substrate and enzyme are kept apart. The system studied here consists of the substrate 2-O-β-D-glucopyranosyl-4-dihydroxy-1,4-benzoxazin-3-one and the enzyme glucan 1,3-β-glucosidase in rye. The aim was to determine the properties of a cell wall β-glucosidase. Two different systems for expression and purification of β-glucosidase fused to a tag were used: a 6xHistidine tag system and a thioredoxin tag system. The sequence of the β-glucosidase had previously been determined so now the gene was subcloned into E.coli. A direct PCR on colonies, a test expression, a restriction digestion of plasmids and sequencing was made to analyze the transformation, which all turned out successful. Then the β-glucosidase solubility was determined. Finally a purification of the β-glucosidase from E.coli under native conditions and a pNPG assay was carried out. For the (His)6-tagged protein, the recombinant β-glucosidase tended to end up in the insoluble pelleted fraction which indicated formation of inclusion bodies. The cell wall 1,3-β-glucosidase was soluble with the thioredoxin system, but the percentage of soluble protein fraction was around 5% only of the total protein. In eluates from a nickel-nitrilotriacetic acid column the presence of recombinant protein was confirmed with Western blot, but contaminating bands were also present. Purified elauted fractions did not exhibit detectable β-glucosidase activity. It was not possible to purify active enzyme. From a BLAST search it was clear that the most similar enzymes all had putative glycosylation sites and lack of glycosylation could be a reason for the protein not to fold properly.
86

The Effects of Acute Running Induced Neuronal Activation on Cerebral GLUT1 and Vascular Plasticity

Liang, Jacky 17 November 2011 (has links)
Morphologic and metabolic change is a known property of the adult brain. A number of behavioural tasks alter local cerebral blood flow and glucose utilisation. The expression of the glucose transporter 1 (GLUT1), which allows the entry of glucose to the brain, also has been shown to change in response to long-lasting neuronal activation. However, little is known about the effect of acute neuronal activation on GLUT1 expression. Using immunohistochemistry and Western blot, we investigated cerebral GLUT1 expression and vasculature density in mice undergoing a 48-hour voluntary wheel running period. The results showed that the striatum was the main region where GLUT1 protein was up-regulated: There was a trend for GLUT1 expression and blood vessels density to be associated with the distance run during the experiment. These results indicate that short-term increased neuronal activation is associated with rapid changes in glucose transport and possibly vascular remodelling.
87

The Effects of Acute Running Induced Neuronal Activation on Cerebral GLUT1 and Vascular Plasticity

Liang, Jacky 17 November 2011 (has links)
Morphologic and metabolic change is a known property of the adult brain. A number of behavioural tasks alter local cerebral blood flow and glucose utilisation. The expression of the glucose transporter 1 (GLUT1), which allows the entry of glucose to the brain, also has been shown to change in response to long-lasting neuronal activation. However, little is known about the effect of acute neuronal activation on GLUT1 expression. Using immunohistochemistry and Western blot, we investigated cerebral GLUT1 expression and vasculature density in mice undergoing a 48-hour voluntary wheel running period. The results showed that the striatum was the main region where GLUT1 protein was up-regulated: There was a trend for GLUT1 expression and blood vessels density to be associated with the distance run during the experiment. These results indicate that short-term increased neuronal activation is associated with rapid changes in glucose transport and possibly vascular remodelling.
88

Epidemiological and Bacteriological Aspects of Spotted Fever Rickettsioses in Humans, Vectors and Mammals in Sweden

Elfving, Karin January 2013 (has links)
Rickettsiae are obligate intracellular gram-negative bacteria transmitted by arthropod vectors. Rickettsiae sometimes cause disease in humans, typically with high fever, headache and occasionally an eschar. In Sweden, Rickettsia helvetica, belonging to the spotted fever group, is the only tick-transmitted rickettsia found free in nature. The pathogenic roll of R. helvetica has not been fully investigated, but it has been implicated in aneruptive fever and cardiac disease. This thesis describes parts of the transmission pathways of rickettsiae in Sweden. Rickettsia infection rates in ticks collected from birds were analysed, and the birds’ role as disseminators and reservoirs was studied. We found that more than one in ten ticks was infected with rickettsia bacteria, predominantly R. helvetica, and that migrating birds contribute not only to long-distance dispersion of bacteria, but also to an inflow of novel and potentially pathogenic rickettsia species, in this case R. monacensis and R. sp. strain Davousti-like species, into Sweden. Further, wild and domestic animals were found to have seroreactivity against R. helvetica, which shows that they are exposed and susceptible to rickettsia. Their role as reservoirs has not been determined, yet they may indirectly be involved in transmission of rickettsia to humans by infected ticks feeding on them. The seroreactivity in humans was also studied. Patients investigated for suspected Borrelioses and blood donors had detectable antibodies against Rickettsia spp., with the highest prevalence detected in the suspected Borreliosis group. This shows that humans in Sweden are exposed to and develop an immune response against rickettsia. The suspicion that R. helvetica may cause severe symptoms was verified by a patient with subacute meningitis where the bacterium was shown for the first time to cause an invasive infection with CNS involvement and where the bacterium was isolated from the patient’s cerebrospinal fluid. Growth characteristics and morphology of R. helvetica were studied to better understand invasiveness and virulence. The findings indicate that the invasiveness is comparable with other rickettsia, though R. helvetica seems to have a stable but slightly slower growth.  Rickettsia helvetica is endemic in Sweden and therefore needs to be considered when investigating disease after a tick bite. / Rickettsia är en liten, strikt intracellulär, gramnegativ bakterie som sprids med vektorer som fästingar, löss och loppor. Bakterien kan orsaka Rickettsios hos människa, en sjukdom där de vanligaste symtomen är hög feber, huvudvärk, muskelvärk och i vissa fall ett bettmärke (eschar). I Sverige är Rickettsia helvetica, som tillhör spotted fever gruppen (SFG), den enda fästingöverförda rickettsia bakterien som hittats allmänt i naturen. Patogeniciteten för R. helvetica är ofullständigt utredd, men ”aneruptive fever” och hjärtmuskelinflammation har rapporterats. Avhandlingen beskriver delar av smittkedjan för SFG rickettsia i Sverige. Bakteriernas förekomst i fästingar plockade från fåglar har studerats, likaså det ekologiska tryck som flyttfåglars bärarskap av infekterade fästingar bidrar med när de korsar olika världsdelar. Mer än var tionde fästing var infekterad med rickettsia bakterier, i huvudsak R. helvetica. Det visade sig att flyttfåglar bidrar inte bara till långväga spridning av bakterier utan även till införsel av nya potentiellt patogena rickettsiaarter, i detta fall identifierades R. monacensis och en R. sp strain Davousti liknande art. Vidare analyserades seroreaktivitet mot Rickettsia helvetica hos både tamdjur och vilda djur, vilket visade på antikroppsutveckling, som uttryck för smittexposition, i mer än vart femte djur. Djurens roll som reservoar för bakterien är inte klarlagd, men oavsett är djuren indirekt involverade i spridningen av bakterien till människa via infekterade fästingar som suger blod. Seroreaktivitet hos människa har också studerats. Patienter, provtagna på grund av misstanke om borreliainfektion, samt blodgivare hade detekterbara antikroppar mot Rickettsiae, med högst prevalens i gruppen med misstänkt borreliainfektion. Fynden visar att människor i Sverige är exponerade för och utvecklar en immunreaktion mot rickettsia. Att R. helvetica skulle kunna ge allvarlig sjukdom verifieras av ett patientfall med subakut meningit där bakterien för första gången visats ge invasiv infektion med påverkan på nervsystemet (CNS engagemang) och där bakterien isolerats från patientens ryggmärgsvätska.  Morfologi och tillväxtegenskaper för R. helvetica undersöktes för att bättre förstå bakteriens invasivitet och virulens. Fynden indikerar att invasiviteten är jämförbar med andra rickettsiaarter men R. helvetica verkar ha en stabil men något långsammare tillväxt. Rickettsia helvetica är endemisk i Sverige och måste tas i beaktande vid sjukdomsutredning efter ett fästingbett.
89

Identification Of The New Immunogenic Proteins Of Bordetella Pertussis By Immunoproteomics

Altindis, Emrah 01 April 2007 (has links) (PDF)
The genus Bordetella contains several pathogenic species generally associated with upper respiratory tract infections in warm-blooded animals. Bordetella pertussis is the etiologic agent of whooping cough. Whooping cough is presently one of the ten most common causes of death from infectious diseases and reported by the World Health Organisation (WHO) to cause 50 million cases and 350000 deaths worldwide per year, mainly among unvaccinated individuals in poor countries. The term proteome, in analogy to the term genome, was coined to describe the complete set of proteins that an organism has produced under a defined set of conditions. Proteomics has been used to identify novel bacterial vaccine candidates against several human pathogens. Fueled by growing DNA sequence information, the analysis of the proteome becomes a valuable and useful tool for antigen discovery. Much of information about immunogenic component can be derived from proteomics coupled to Western blotting, namely immunoproteomics. v In the present study, we report first immunoproteomics analysis to identify candidate antigens of B. pertussis for vaccine development. Different sera from mice, which were immunized or challenged with B. pertussis, were analyzed for reactivity by Western blot against whole cell extracts of B. pertussis Tohama and Saadet strains separated by 2-DE. We identified 15 immunogenic proteins of Bordetella pertussis as a total (60 kDa chaperonin, heat shock protein, serum resistance protein, putative substrate-CoA ligase, ATP-dependent protease, preprotein translocase secA subunit, S-adenosylmethionine synthetase, elongation factor Tu, RNA polymerase alpha subunit, ketol-acid reductoisomerase, pertactin, lysyl-tRNA synthetase, serum resistance protein, carbamoyl-phosphate synthase large chain, 30S ribosomal protein S1 subunit), 6 of which being identified as immunogenic in a pathogenic microbe (ATP-dependent protease, carbamoylphosphate synthase large chain, lysyl-tRNA synthetase, putative chromosome partition protein, preprotein translocase secA subunit, 30S ribosomal protein S1 subunit) and 5 identified as immunogenic for Bordetella pertussis (RNA polymerase alpha subunit, S-adenosylmethionine synthatase, putative substrate-CoA ligase, elongation factor Tu, ketol-acid reductoisomerase) for the first time.
90

Small Proline Rich Protein-2 Expression and Regulation in the Caco-2 model of Intestinal Epithelial Differentiation along the Crypt-Villus Axis

Hui, Patrick J.H. 28 April 2008 (has links)
Small proline-rich protein-2 (SPRR2) functions as a determinant of flexibility and permeability in the mature cornified envelope of the skin. SPRR2 is strongly upregulated by the commensal flora and may mediate signaling to differentiated epithelia of the small intestine and colon. Yet, SPRR2 function in the GI tract is largely unexplored. Using the Caco-2 model of intestinal epithelial differentiation along the crypt-villus axis, we hypothesized that SPRR2 would be preferentially expressed in post-confluent differentiated Caco-2 cells and examined SPRR2 regulation by the protein kinase A pathway (PKA) and short chain fatty acids (SCFAs). Differentiation-dependent SPRR2 expression was examined in cytoskeletal-, membrane-, and nuclear-enriched fractions by immunoblotting and confocal immunofluorescence. We studied the effect of SCFAs, known inducers of differentiation, on SPRR2 expression in pre-confluent undifferentiated Caco-2 cells and explored potential mechanisms involved in this induction using MAP kinase inhibitors. SPRR2 expression was also compared between HIEC crypt cells and 16 to 20 week primary fetal villus cells as well as in different segments in mouse small intestine and colon. We determined if SPRR2 is increased by gram negative bacteria such as S. typhimurium. SPRR2 expression increased in a differentiation-dependent manner in Caco-2 cells and was present in human fetal epithelial villus cells but absent in HIEC crypt cells. Differentiation-induced SPRR2 was down-regulated by 8-Br-cAMP as well as by forskolin/IBMX co-treatment. SPRR2 was predominantly cytoplasmic and did not accumulate in Triton X-100-insoluble cytoskeletal fractions. SPRR2 was present in the membrane- and nuclear-enriched fractions and demonstrated co-localization with F-actin at the apical actin ring. No induction was seen with the specific HDAC inhibitor trichostatin A, while SCFAs and the HDAC inhibitor SBHA all induced SPRR2. SCFA responses were inhibited by MAP kinase inhibitors SB203580 and U0126, thus suggesting that the SCFA effect may be mediated by orphan G-protein receptors GPR41 and GPR43. S. typhimurium induced SPRR2 in undifferentiated cells. We conclude that SPRR2 protein expression is associated with differentiated epithelia and is regulated by PKA signaling and by by-products of the bowel flora. This is the first report to establish an in vitro model to study the physiology and regulation of SPRR2. / Thesis (Master, Anatomy & Cell Biology) -- Queen's University, 2008-04-25 12:39:06.427 / This work was funded by the CIHR GIDRU Training Grant and Aid in Research from Crohn's and Colitis Foundation of Canada

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