57 research outputs found
Musik som handling. Verkanalys, interpretation och musikalisk gestaltning. Med ett studium av Anders Eliassons Quartetto d'Archi
No full textDisputationen börjar med att Anders Tykesson håller ett interpretationsseminarium kl 10.30. Medverkar gör en musikensemble från Högskolan för scen och musik. Stenhammars stråkkvartett nr 2 är i fokus. Själva disputationsakten börjar kl 13.The aim of the dissertation is to illustrate the potential musical analysis has in the
development of artistic questions with regard to the interpretation and performance
of western art music. The analyses of the dissertation focus on Quartetto
d’Archi, by the Swedish composer Anders Eliasson, and discussions of music as
action, music as emotional expression, music as motion and music as mimesis are
based on the four movements of this string quartet. The methods which are used
are the very ones the project examines, namely the analysis of and the reflection
on the musical work. The author has attempted to gain a deeper knowledge of the
work and its possible interpretations by means of a comparative study of other
music and literature within the theory of music and within philosophical thinking.
The hermeneutics of Hans–Georg Gadamer and Paul Ricoeur are significant
to the thesis. For example, the author claims that Ricoeur’s concept of interpretation,
in which understanding interacts with explanation, and where the interpreter
“appropriates” the text, could be applied to musical interpretation. References
in music, or in artworks in general, to phenomena, actions and concepts
may be explained through the concept of mimesis. Within the doctoral project,
the author has worked with chamber ensembles in the form of seminars at the
Academy of Music and Drama, the University of Gothenburg.
One of the central claims of the thesis is that the musical work opens up to the
possibilities of interpretation through its own way of being, in the way it expresses
itself in its structures. Questions of the significance of music must be posed to the
musical work itself, which answers through different categories of interpretation;
it is by means of these categories of interpretation that the meaning and significance
of a musical work can be interpreted. Four categories are presented: processual
interpretation, narrative interpretation, characterial interpretation and emotional
interpretation
Formation of Iduronic Acid during Chondroitin/Dermatan Sulfate Biosynthesis
No full textAll animals and some bacteria can synthesize linear polysaccharides with a backbone of repeating disaccharideunits, called glycosaminoglycans (GAGs). The GAGs are either attached to a protein core, as in proteoglycans (PGs), or exist as free polymer chains, as in hyaluronan. One of the most common types of GAGs is chondroitin/dermatan sulfate (CS/DS), where the repeating disaccharide backbone consists of the two epimeric carbohydrates glucuronic and iduronic acid (GlcA/IdoA), linked to N-acetylgalactosamine (GalNAc). The GAG polymer is linked to a core protein and can be sulfated at up to three positions in each disaccharide unit. The GAGs can bind cytokines and growth factors and are directly involved in receptor interactions. For example, the presence and structure of CS/DS is important for migration and invasion of cancer cells, development of atherosclerosis, neuronal outgrowth, and malaria infection.The aim of this work was to understand the role and mode of action of three important enzymes involved in the biosynthesis of CS/DS; namely dermatan sulfate epimerase 1 and 2 (DS-epi1 and 2) and dermatan 4-O- sulfotransferase 1 (D4ST1). The major findings are summarized below.Mice deficient in DS-epi1 and 2 were carefully characterized in terms of their phenotypes and biochemical GAG composition. The resulting mice were completely devoid of iduronic acid, and the resulting CS chains were structurally different from the wild type chains. Consequently, a vast majority of the DKO mice died perinatally, with widely variable phenotypes at birth or late embryonic stages. Together, our results indicate an important role of dermatan sulfate in embryonic development and perinatal survival.Further, we introduced a new technique to study the activity and mode of action of DS-epi1, where we combined a mass spectrometric analysis of heavy-atom labeled oligosaccharides with in silico simulations. Using an assay buffer prepared with heavy water (D2O) we analyzed the site-specific incorporation of deuterium into oligosaccharides of different lengths by collision-induced dissociation mass spectrometry (MS). The results from the MS experiments were then correlated to enzyme-substrate models prepared in silico, and we presented a model for the in vitro mode of action of DS-epi1.We also reported findings regarding the possible interaction between DS-epi1 and D4ST1. We could show that DS-epi1 yields only a few iduronic acid residues at a slow speed, whereas the co-incubation with D4ST1 increased the speed of epimerization five-fold. The enzymes were cross-linked and then subjected to gel electrophoresis, where larger complexes were observed. MS showed that the complexes contained both DS-epi1 and D4ST1, suggesting that DS-epi1 and D4ST1 interact during the formation of CS/DS.Finally, we described a novel method for recombinant production of DS. Recombinantly expressed DS-epi1 and D4ST1 were used, together with a uronosyl 2-O-sulfotransferase and a bacterial polysaccharide, to produce a DS polymer composed of IdoA-2S-GalNAc-4S. These CS/DS polymers were capable of inactivation of thrombin with heparin cofactor II in the same order of magnitude as with heparin
Assays for Evaluation of Substrates for and Inhibitors of β-1,4-Galactosyltransferase 7
No full textβ-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the synthesis of two classes of glycosaminoglycans (GAG), i.e., heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS). GAG chains are linear polysaccharides of alternating hexuronic acid and N-acetylhexosamine residues, commonly linked to core proteins to form proteoglycans with important roles in the regulation of a range of biological processes. The biosynthesis of GAGs is initiated by xylosylation of a serine residue of the core protein followed by galactosylation, catalyzed by β4GalT7. The biosynthesis can also be initiated by xylosides carrying hydrophobic aglycons, such as 2-naphthyl β-D-xylopyranoside. We have cloned and expressed β4GalT7, and designed a cell-free assay to measure the activity of this enzyme. The assay employs a 96-well plate format for high throughput. In this chapter, we describe the cloning, expression, and purification of β4GalT7, as well as assays proposed for development of substrates for GAG priming and for investigating inhibitors of β4GalT7
Quantification Of Glycosaminoglycans In Knee Synovial Fluid From Different Patient Groups And Knee-Healthy Subjects Using High Performance Liquid Chromatography
No full textPurpose: The glycosaminoglycans chondroitin sulfate (CS) and hyaluronic acid (HA) are important for the normal function of articular cartilage, and changes of their sulfation and concentration may play a role in the pathogenesis of osteoarthritis (OA). Therefore, these glycans may be clinically useful as biomarkers in OA management. The purpose of this study was to analyze the CS and HA pattern in knee synovial fluid from different subject groups.Methods: OA patients (n=20, age=34-75 years, 45% women), recently knee-injured patients (0-77 days from injury, n=46, age 15-64 years, 15% women), previously knee-injured patients (88 days-21 years from injury, n=30, age 25-65 years, 17% women) and knee-healthy subjects (n=22, age 17-48 years, 23% women) were selected from a cross-sectional convenience cohort. CS and HA in individual synovial fluid samples, a synovial fluid quality control sample (SF-QC; a pool of synovial fluids) and a CS quality control sample (CS-QC) were digested with chondroitinase ABC and glucose oxidase overnight. Samples and glycan standards (CS [n=6] and HA [n=1] standards) were labelled with 2-aminoacridone (AMAC) and analyzed using a quantitative high performance liquid chromatography (HPLC) assay. In total, 118 synovial fluid samples were run, whereof 34 in duplicates. SF-QC, CS-QC and standards were run in duplicates.Since the CS and HA data were not normally distributed, non-parametric analyses for group comparisons were done (Student’s T-test for age analysis, Chi-square test for sex analysis and Mann-Whitney U test for CS and HA analysis). The significance level was set at pResults: HPLC assay validation: The intra experiment coefficient of variation (CV) for the synovial fluid samples (n=36; including SF-QC) was 0.03-36.9% (median 5.4%) for CS and 0.4-44.9% (median 7.6%) for HA; intra CV for the CS-QC sample was 0.01-3.7%, and for the standards it was 0.2-6.7% for CS and 1.9-7.1% for HA. The inter experiment CV for SF-QC (n=5 experiments) was 9.8-17.5% for CS and 15.1% for HA; the inter CV for CS-QC (n=4 experiments) was 3.4-6.1%, and for the standards (n=5 experiments) it was 0.01-0.07% for CS and 0.1% for HA. Glucose oxidase was added to remove glucose that otherwise co-elutes with non-sulfated CS; it did not affect the CS and HA standards (data not shown). Group comparisons: Comparisons were made between the knee-healthy control group and the OA, recent injury and previous injury groups respectively, as well as between the recent injury and previous injury groups. There was no difference in sex between either of the groups (p=0.074-0.866). There was no difference in age between the knee-healthy group and the recent injury group (p=0.330), but the knee-healthy group was younger than the previous injury group and the OA group (pConclusions: Our data suggests that the groups with knee pathologies have higher concentrations of some CS variants and HA than the knee-healthy group. We also see a trend of higher levels of CS variants in the recent knee injury group compared to the previous knee injury group. This indicates that there is both an acute and chronic increase in the concentrations of CS variants and HA in synovial fluid following knee injury and/or cartilage damage
Production and HPLC-Based Disaccharide Analysis of Xyloside-Primed Glycosaminoglycans
No full textAlthough glycosaminoglycans (GAGs) are known to be involved in a variety of physiological and pathological processes, knowledge about their expression by cells or tissues, the GAGome, is limited. Xylosides can be used to induce the formation of GAGs without the presence of a proteoglycan core protein. The administration of xylosides to living cells tends to result in a considerable amplification in GAG production, and the xylosides can, therefore, be used as analytical tools to study the GAG produced by a certain cell type. One of the most common ways to analyze the GAGs structurally is by disaccharide analysis, which involves depolymerization of the GAGs into disaccharides, fluorescent labeling of the disaccharides with 2-aminoacridone, and quantification using high-pressure liquid chromatography (HPLC). Here, we describe the procedure of producing xyloside-primed GAGs and how to study them structurally by disaccharide analysis
Quantification Of Glycosaminoglycans In Knee Synovial Fluid From Different Patient Groups And Knee-Healthy Subjects Using High Performance Liquid Chromatography
No full textPurpose: The glycosaminoglycans chondroitin sulfate (CS) and hyaluronic acid (HA) are important for the normal function of articular cartilage, and changes of their sulfation and concentration may play a role in the pathogenesis of osteoarthritis (OA). Therefore, these glycans may be clinically useful as biomarkers in OA management. The purpose of this study was to analyze the CS and HA pattern in knee synovial fluid from different subject groups. Methods: OA patients (n=20, age=34-75 years, 45% women), recently knee-injured patients (0-77 days from injury, n=46, age 15-64 years, 15% women), previously knee-injured patients (88 days-21 years from injury, n=30, age 25-65 years, 17% women) and knee-healthy subjects (n=22, age 17-48 years, 23% women) were selected from a cross-sectional convenience cohort. CS and HA in individual synovial fluid samples, a synovial fluid quality control sample (SF-QC; a pool of synovial fluids) and a CS quality control sample (CS-QC) were digested with chondroitinase ABC and glucose oxidase overnight. Samples and glycan standards (CS [n=6] and HA [n=1] standards) were labelled with 2-aminoacridone (AMAC) and analyzed using a quantitative high performance liquid chromatography (HPLC) assay. In total, 118 synovial fluid samples were run, whereof 34 in duplicates. SF-QC, CS-QC and standards were run in duplicates.Since the CS and HA data were not normally distributed, non-parametric analyses for group comparisons were done (Student’s T-test for age analysis, Chi-square test for sex analysis and Mann-Whitney U test for CS and HA analysis). The significance level was set at p Results: HPLC assay validation: The intra experiment coefficient of variation (CV) for the synovial fluid samples (n=36; including SF-QC) was 0.03-36.9% (median 5.4%) for CS and 0.4-44.9% (median 7.6%) for HA; intra CV for the CS-QC sample was 0.01-3.7%, and for the standards it was 0.2-6.7% for CS and 1.9-7.1% for HA. The inter experiment CV for SF-QC (n=5 experiments) was 9.8-17.5% for CS and 15.1% for HA; the inter CV for CS-QC (n=4 experiments) was 3.4-6.1%, and for the standards (n=5 experiments) it was 0.01-0.07% for CS and 0.1% for HA. Glucose oxidase was added to remove glucose that otherwise co-elutes with non-sulfated CS; it did not affect the CS and HA standards (data not shown). Group comparisons: Comparisons were made between the knee-healthy control group and the OA, recent injury and previous injury groups respectively, as well as between the recent injury and previous injury groups. There was no difference in sex between either of the groups (p=0.074-0.866). There was no difference in age between the knee-healthy group and the recent injury group (p=0.330), but the knee-healthy group was younger than the previous injury group and the OA group (p Conclusions: Our data suggests that the groups with knee pathologies have higher concentrations of some CS variants and HA than the knee-healthy group. We also see a trend of higher levels of CS variants in the recent knee injury group compared to the previous knee injury group. This indicates that there is both an acute and chronic increase in the concentrations of CS variants and HA in synovial fluid following knee injury and/or cartilage damage
Production and HPLC-Based Disaccharide Analysis of Xyloside-Primed Glycosaminoglycans
No full textAlthough glycosaminoglycans (GAGs) are known to be involved in a variety of physiological and pathological processes, knowledge about their expression by cells or tissues, the GAGome, is limited. Xylosides can be used to induce the formation of GAGs without the presence of a proteoglycan core protein. The administration of xylosides to living cells tends to result in a considerable amplification in GAG production, and the xylosides can, therefore, be used as analytical tools to study the GAG produced by a certain cell type. One of the most common ways to analyze the GAGs structurally is by disaccharide analysis, which involves depolymerization of the GAGs into disaccharides, fluorescent labeling of the disaccharides with 2-aminoacridone, and quantification using high-pressure liquid chromatography (HPLC). Here, we describe the procedure of producing xyloside-primed GAGs and how to study them structurally by disaccharide analysis
Assays for Evaluation of Substrates for and Inhibitors of β-1,4-Galactosyltransferase 7
No full textβ-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the synthesis of two classes of glycosaminoglycans (GAG), i.e., heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS). GAG chains are linear polysaccharides of alternating hexuronic acid and N-acetylhexosamine residues, commonly linked to core proteins to form proteoglycans with important roles in the regulation of a range of biological processes. The biosynthesis of GAGs is initiated by xylosylation of a serine residue of the core protein followed by galactosylation, catalyzed by β4GalT7. The biosynthesis can also be initiated by xylosides carrying hydrophobic aglycons, such as 2-naphthyl β-D-xylopyranoside. We have cloned and expressed β4GalT7, and designed a cell-free assay to measure the activity of this enzyme. The assay employs a 96-well plate format for high throughput. In this chapter, we describe the cloning, expression, and purification of β4GalT7, as well as assays proposed for development of substrates for GAG priming and for investigating inhibitors of β4GalT7
Synthesis of Double-Modified Xyloside Analogues for Probing the β4GalT7 Active Site
No full textMonosubstituted naphthoxylosides have been shown to function as substrates for, and inhibitors of, the enzyme β4GalT7, a key enzyme in the biosynthetic pathway leading to glycosaminoglycans and proteoglycans. In this article, we explore the synthesis of 16 xyloside analogues, modified at two different positions, as well as their function as inhibitors of and/or substrates for the enzyme. Seemingly simple compounds turned out to require complex synthetic pathways. A meta-analysis of the synthetic work shows that, regardless of the abundance of methods available for carbohydrate synthesis, even simple modifications can turn out to be problematic, and double modifications present additional challenges due to conformational, steric, and stereoelectronic effects
Hydroxylated oxanes as xyloside analogs for determination of the minimal binding requirements of β4GalT7
No full textβ-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the biosynthesis of glycosaminoglycan (GAG) chains. Natural and synthetic xylosides can be used to both inhibit and prime GAG synthesis by acting as inhibitors or substrates for β4GalT7. In this report, we exploit hydroxylated oxanes as deoxygenated xyloside analogs to clarify the minimum protein-ligand interactions required for galactosylation and/or inhibition. Enantiomerically pure substances were synthesized using a chiral pool approach whereas the corresponding racemates were obtained from simple starting materials. The results of a β4GalT7 assay show that a single hydroxyl group on an oxane ring is insufficient to induce galactosylation or inhibition, which implies that at least two substituents, one of which being 3-OH, needs to be present
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