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1
Dupraz, Louise. "L'effet Proteus : Performances motrices et cognitives en situation d'incorporation d'un avatar". Electronic Thesis or Diss., Chambéry, 2024. http://www.theses.fr/2024CHAMA006.
Testo completoAbstract (sommario):
La représentation corporelle, étonnamment plastique, peut présenter des déviations importantes par rapport aux frontières du corps biologique. Les paradigmes d'incorporation illustrent cette plasticité. Il est possible, par exemple, d'intégrer à la représentation corporelle une main en caoutchouc, ou de faire émerger un sentiment d'incorporation pour un avatar d'âge différent de celui du participant. L'incorporation d'un avatar s'accompagne de conséquences perceptives, cognitives et comportementales, ces dernières ayant largement été étudiées dans le cadre de l'effet Proteus. Par exemple, l'incorporation d'un avatar attractif, plutôt qu'un avatar peu attractif, conduit les participants à se montrer plus confiants et extravertis aux cours des échanges, conformément aux stéréotypes relatifs à la beauté. Ce phénomène de conformisme aux stéréotypes associés à l'avatar incorporé a été discuté au regard de différents processus : processus d'auto-perception, effet d'amorçage, processus d'incorporation, adhésion aux stéréotypes. Toutefois, les arguments empiriques sont insuffisants pour comprendre précisément les mécanismes sous-jacents à l'apparition du phénomène. Un premier objectif de ce travail de thèse était de confirmer l'intervention d'un mécanisme additionnel à celui d'un effet d'amorçage situationnel direct dans l'apparition de l'effet Proteus. Conformément à l'hypothèse, les études ont démontré le phénomène au-delà de l'activation des stéréotypes associés à l'avatar. Un second objectif était de tester le rôle causal du processus d'incorporation sur l'apparition de l'effet Proteus. Contrairement à ce qui était attendu, un effet Proteus a été retrouvé indépendamment du fait de considérer le corps de l'avatar comme étant sien. Les résultats sont en faveur de l'apparition du phénomène dès lors qu'une relation identitaire est instaurée avec l'avatar. Un dernier objectif visait à examiner la contribution d'un changement de perception de soi dans l'apparition de l'effet Proteus. Les études n'ont toutefois pas permis d'en attester. En somme, le présent travail de thèse apporte des éléments de compréhension de l'effet Proteus et incite à poursuivre la démarche d'approfondissement théorique vers l'étude des mécanismes relatifs à la perception de soi implicite. Améliorer la compréhension des mécanismes sous-jacents au phénomène offre des perspectives dans le domaine de la prise en charge thérapeutique et de la prévention des risques psycho-sociauxBody representation is surprisingly plastic and can deviate from the boundaries of the biological body. Embodiment paradigms illustrate this plasticity. For example, it is possible to integrate a rubber hand in the body representation, or to elicit a sense of embodiment for an avatar of a different age from the participant. The embodiment of an avatar is associated with perceptual, cognitive, and behavioral consequences, which have been extensively studied in the context of the Proteus effect. For instance, the embodiment of an attractive avatar, compared to an unattractive one, led participants to be more confident and extroverted during exchanges, in line with stereotypes related to beauty. In the literature, this conformism to the stereotypes associated with the avatar has been discussed regarding different processes: self-perception process, priming effect, embodiment process, stereotype endorsement. However, empirical arguments are still insufficient to provide a precise explanation of the mechanisms underlying this phenomenon. A first objective of this thesis was to confirm the involvement of an additional mechanism to that of a direct priming effect in the occurrence of the Proteus effect. In line with the hypothesis, the studies demonstrated that the phenomenon occurs beyond the mere activation of stereotypes associated with the avatar. A second objective was to investigate the causal role of embodiment on the Proteus effect. Contrary to expectations, a Proteus effect was observed regardless of considering the avatar's body as one's own. The results support the occurrence of the phenomenon as long as an identity relationship is established with the avatar. A last objective was to examine the contribution of a self-perception change in the occurrence of the Proteus effect. However, the studies did not provide any conclusive evidence for this hypothesis. In summary, the present thesis provides new insights into the Proteus effect and suggests further theoretical investigation into the implicit self-perception mechanisms. A better understanding of the mechanisms underlying the Proteus effect promises perspectives in clinical practice and in prevention of psycho-social risks
2
Chilukuri, Lakshmi N. "The effect of pressure on DNA-binding proteins from piezosensitive and piezophilic bacteria /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035908.
Testo completo
3
Liu, Ziqiang. "Molecular analysis and functional characterization of Nucleosome Assembly Protein 1 (NAP1) family proteins in plants". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13132.
Testo completoAbstract (sommario):
Eukaryotic genomes are packaged into chromatin, a regularly repeated structure whose fundamental building block is the nucleosome. Each nucleosome core particle is composed of a histone octamer consisting of two molecules each of the core histones H2A, H2B, H3, and H4, around which approximately 146–147 bp of DNA is wrapped. The assembly of nucleosome is the first step of chromatin assembly which is important for the chromatin structure affecting a broad ranges of biological events including DNA replication, repair, recombination, transcription, cell differentiation, proliferation, and organism development, and is fulfilled with the help of histone chaperones, which are important for the organization and dynamics of chromatin templates, and are involved in the storage, translocation to the nucleus and exchange of histones and their deposition onto the DNA for replication-dependent chromatin assembly. [. . . ].
4
Praneet, Opanasopit. "Effect of Serum Mannan Binding Protein on Tissue Disposition of Glycosylated Proteins and Liposomes". 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/150103.
Testo completo
5
Montalvo, Acosta Joel José. "Computational approaches to molecular recognition : from host-guest to protein-ligand binding". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF051/document.
Testo completoAbstract (sommario):
La reconnaissance moléculaire est un problème très intéressant et surtout un défi actuel pour la chimie biophysique. Avoir des prévisions fiables sur la reconnaissance spécifique entre les molécules est hautement prioritaire, car il fournira un aperçu des problèmes fondamentaux et suscitera des applications technologiques pertinentes. La thèse présentée ici est centrée sur une analyse quantitatif de la reconnaissance moléculaire en solution pour la liaison l'hôte-invité, la liaison protéine-ligand et la catalyse. Le cadre de la mécanique statistique utilisé pour décrire l'état de la technique de liaison récepteur-ligand est un point d'inflexion pour le développement de nouvelles méthodes améliorées. En fait, un modèle très performant et précis a été obtenu pour l'analyse de la liaison hôte-invité. Enfin, les modèles présentés ont été utilisés comme outils prédictifs fiables pour la découverte de nouvelles entités chimiques destinées à améliorer la catalyse en solutionMolecular recognition is a very interesting problem, and foremost, a current challenge for biophysical chemistry. Having reliable predictions on the specific recognition between molecules is highly priority as it will provide an insight of fundamental problems and will raise relevant technological applications. The dissertation presented here is centered on a quantitative analysis of molecular recognition in solution for host-guest, protein-ligand binding and catalysis. The statistical mechanics framework used to describe the state-of-the-art for receptor-ligand binding is an inflection point for the developing of new improved and methods. In fact, a highly performanced and accurate model was obtained for the analysis of host-guest binding. Finally, the presented models were used as a reliable predictive tools for discovering new chemical entities for enhance catalysis in solution
6
Rassadi, Roozbeh. "The effect of stress on nuclear protein transport : classical nuclear protein transport versus the nuclear transport of heat shock proteins". Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33476.
Testo completoAbstract (sommario):
The stress response is conserved among eukaryotes and affects different cellular functions including protein transport. Here, we have investigated the effect of different types of stress on classical nuclear protein import as well as nuclear import of Ssa4p family of heat shock proteins in Saccharomyces cerevisiae.Under normal conditions, Aequorea victoria green fluorescent protein (GFP), carrying a classical nuclear localization sequence (cNLS-GFP) is nuclear. However, cNLS-GFP equilibrates throughout the cell upon exposure to heat, ethanol, H2O2 or starvation. Redistribution of the small GTPase Gsp1p, a soluble nuclear transport factor, correlates with cNLS-GFP equilibration. This suggests that a collapse of the Gsp1p gradient underlies the inhibition of classical nuclear protein import. In contrast to cNLS-GFP, the cytoplasmic heat shock protein Ssa4p accumulates in nuclei when classical nuclear import is inhibited. The N-terminal 236 amino acid residues of Ssa4p are sufficient for nuclear localization of Ssa4p-GFP upon heat and ethanol stress. The nuclear localization of Ssa4p(1--236)-GFP requires components of Gsp1-GTPase system, but is independent of Srp1p, the cNLS receptor.
Ssa4p(16--642)-GFP accumulates in nuclei of starving cells, mediated by a hydrophobic stretch of amino acid residues in its N-terminal domain. This nuclear localization is reversible upon addition of fresh medium and its export is sensitive to oxidants and temperature-dependent.
7
Jugniot, Natacha. "Molecular imaging of serine protease activity-driven pathologies by magnetic resonance". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0141/document.
Testo completoAbstract (sommario):
Ce travail porte sur le développement de sondes peptidiques pour le suivi de la protéolyse par spectroscopie de résonance paramagnétique électronique (RPE) et pour l'imagerie in vivo par résonance magnétique rehaussée de l’effet Overhauser (OMRI). Plus précisément, ce travail étudie pour la première fois une famille d’agents d’imagerie appelée « nitroxyde à déplacement de raies spectrales » spécifique d’activités enzymatiques. L'activité protéolytique, entraînant un décalage de 5 G dans les constantes de couplages hyperfins, permet une quantification individuelle des espèces substrat et produit par RPE et une excitation sélective par OMRI. Trois substrats ont été élaborés, montrant une spécificité enzymatique pour l’élastase du neutrophile (NE) (MeO-Suc-Ala-Ala-Pro-Val-Nitroxyde & Suc-Ala-Ala-Pro-Val-Nitroxyde), et pour la chymotrypsine et la cathepsine G (Suc-Ala-Ala-Pro-Phe-Nitroxyde). Les constantes enzymatiques ont montré de bonnes valeurs avec globalement, Km = 28 ± 25 µM et kcat = 19 ± 3 s-1. Ex vivo, l’utilisation des substrats NE en OMRI a révélé un contraste élevé dans les lavages broncho-alvéolaires de souris sous stimulus inflammatoire. Les rehaussements de signaux IRM sont en corrélation avec la sévérité de l’inflammation. L'irradiation à la fréquence RPE de 5425,6 MHz a permis d'accéder à la bio-distribution des substrats in vivo et pourrait ainsi servir d’outil diagnostic. Les perspectives à moyen terme de ce travail reposent sur le développement de l’OMRI à très faibles champs magnétiques en vue d’une application chez l’hommeThis work focuses on substrate-based probes for proteolysis monitoring by Electron Paramagnetic Resonance spectroscopy (EPR) and for in vivo imaging by Overhauser-enhanced Magnetic Resonance (OMRI). More precisely, this work investigates for the first time a family of MRI agents named “line-shifting nitroxide” specific for proteolytic activities. Proteolytic action results in a shift of 5 G in EPR hyperfine coupling constants allowing individual quantification of substrate and product species by EPR and selective excitation by OMRI. Three substrates were worked out, showing enzymatic specificity for neutrophil elastase (MeO-Suc-Ala-Ala-Pro-Val-Nitroxide & Suc-Ala-Ala-Pro-Val-Nitroxide), and for Chymotrypsin/Cathepsin G (Suc-Ala-Ala-Pro-Phe-Nitroxide). Enzymatic constants were remarkably good with globally Km = 28 ± 25 µM and kcat = 19 ± 3 s-1. Ex vivo, the use of NE substrates in OMRI revealed a high contrast in bronchoalveolar lavages of mice under inflammatory stimulus. MRI signal enhancements correlate with the severity of inflammation. Irradiation at the RPE frequency of 5425.6 MHz provided access to the bio-distribution of substrates in vivo and could thus serve as a diagnostic tool. The medium-term perspectives of this work are based on the development of OMRI with very low magnetic fields for human application
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Odunuga, Odutayo Odutola. "Molecular characterization of the tetratricopeptide repeat-mediated interactions of murine stress-inducible protein 1 with major heat shock proteins". Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1007724.
Testo completoAbstract (sommario):
Murine stress-inducible protein 1 (mSTI1) is a co-chaperone that is homologous with the human heat shock protein 70 (Hsp70)/heat shock protein 90 (Hsp90)-organizing protein (Hop). The two proteins are homologues of the highly conserved stress-inducible protein 1 (STI1) family of co-chaperones. The STI1 proteins interact directly and simultaneously at some stage, with Hsp70 and Hsp90 in the formation of the hetero-multi-chaperone complexes that facilitate the folding of signal transducing kinases and functional maturation of steroid hormone receptors. The interactions of mSTI1 with both Hsp70 and Hsp90 is mediated by a versatile structural protein-protein interaction motif, the tetratricopeptide repeat (TPR). The TPR motif is a degenerate 34-amino acid sequence a-helical structural motif found in a significant number of functionally unrelated proteins. This study was aimed at characterizing the structural and functional determinants in the TPR domains of mSTI1 responsible for binding to and discriminating between Hsp70 and Hsp90. Guided by data from Hop's crystal structures and amino acid sequence alignment analyses, various biochemical techniques were used to both qualitatively and quantitatively characterize the contacts necessary for the N-terminal TPR domain (TPR1) of mSTI1 to bind to the C-terminal EEVD motif of heat shock cognate protein 70 (Hsc70) and to discriminate between Hsc70 and Hsp90. Substitutions in the first TPR motif of Lys⁸ or Asn¹² did not affect binding of mSTI1 to Hsc70, while double substitution of these residues abrogated binding. A substitution in the second TPR motif of Asn⁴³ lowered but did not abrogate binding. Similarly, a deletion in the second TPR motif coupled with a substitution of Lys⁸ or Asn¹² reduced but did not abrogate binding. Steady state fluorescence and circular dichroism spectroscopies revealed that the double substitution of Lys⁸ and Asn¹² resulted in perturbations of inter-domain interactions in mSTl1. Together these results suggest that mSTI1-Hsc70 interaction requires a network of electrostatic interactions not only between charged residues in the TPR1 domain of mSTI1 and the EEVD motif of Hsc70, but also outside the TPR1 domain. It is proposed that the electrostatic interactions in the first TPR motif collectively made by Lys⁸ and Asn¹² define part of the minimum interactions required for successful mSTI1-Hsc70 interaction. In the first central TPR domain (TPR1A), single substitution of Lys³°¹ was sufficient to abrogate the mSTI1-Hsp90 interaction. Using a truncated derivative of mSTI1 incapable of binding to Hsp90, residues predicted by crystallographic data to determine Hsp70 binding specificity were substituted in the TPR1 domain. The modified protein had reduced binding to Hsc70, but showed significant binding capacity for Hsp90. In contrast, topologically equivalent substitutions on a truncated derivative of mSTI1 incapable of binding to Hsc70 did not confer Hsc70 specificity on the TPR2A domain. These data suggest that binding of Hsc70 to the TPR1 domain is more specific than binding of Hsp90 to the TPR2A domain. In addition, residues C-terminal of helix A in the second TPR motif of mSTI1 were shown to be important in determining specific binding to Hsc70. Binding assays using surface plasmon resonance spectroscopy showed that the affinities of binding of mSTI1 to Hsc70 and Hsp90 were 2 μM and 1.5 μM respectively. Preliminary in vivo studies revealed differences in the dynamics of binding of endogenous and exogenous recombinant mSTI1 with Hsc70 and Hsp90. The outcome of this study poses serious implications for the mechanisms of mSTI1 interactions with Hsc70 and Hsp90 in the cell.
9
Delgado, Malcom Arturo. "Biochemical Study of Engineered Fluorescent Proteins as Calcium Sensors and the Effect of Calcium and PH in Cell Reproduction and Protein Expression". Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/23.
Testo completoAbstract (sommario):
Calcium plays important roles in both eukaryotic and prokaryotic cells. Its actions help to stabilize cell synthesis, growth and development. In this thesis, studies have been completed to determine effects of calcium and pH on bacterial cell growth and protein expression using the bacterial cell strain E.coli BL21(DE3). Our studies demonstrated the addition of calcium addition in the media does not affect growth but increases protein expression, while reducing the pH from 7 to 4 through the addition of 10mM EGTA in LB media inhibits both. Additionally, we report studies on the design, expression, and purification of fluorescent mCherry variants and their differences in their optical properties, including: extinction coefficients , quantum yields and pKa values. Also, we report progress in the crystallization of two GFP calcium sensors: G1 and D1, using 13 and15% PEG 4000 and 3350 respectively in 50mM HEPES buffer (pH 6.8-7.0) in an effort to optimize crystallization.
10
Li, Jiaxie. "Effects of genetic variants of k-Casein and b-lactoglobulin on heat denaturation of milk proteins and formation of protein complex". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27367.
Testo completoAbstract (sommario):
This study was based on the 462 milk samples collected from approximately 2000 cows registered in Dairy Herd Analysis Service (DHAS). Milk samples from fresh milks were phenotyped by gel electrophoresis. Milk samples were selected according to the nine possibilities of phenotype combination of $ kappa$-casein AA, AB, BB and $ beta$-lactoglobulin AA, AB and BB. Selected milk samples from fresh milks were heated at 25$ sp circ$C, 60$ sp circ$C, 70$ sp circ$C, 80$ sp circ$C and 90$ sp circ$C, respectively. Whole casein and whey protein were separated by adjusting the pH to 4.6. Quantitative determination of milk protein were performed by reverse-phase HPLC. Whole casein was separated to $ kappa$-casein ($ kappa$-Cn), $ beta$-casein ($ beta$-Cn) and $ rm alpha sb{s}$-casein ($ rm alpha sb{s}$-Cn). Whey protein was separated as immunoglobulin (Ig), bovine serum albumin (BSA), $ alpha$-lactalbumin ($ alpha$-La) and $ beta$-lactoglobulin ($ beta$-Lg). Individual milk protein fraction was quantitatively determined by relative peak area and their ratios to whey protein or casein. The denaturation of individual milk protein at different heating temperature was investigated. (Abstract shortened by UMI.)
11
Linley, Lisa K. "The effect of varying levels of dietary protein on carcass composition of eleven- and eighteen-month-old male rats". Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80039.
Testo completoAbstract (sommario):
Carcass composition of male Sprague-Dawley rats, aged 11 and 18 months, in response to varying levels of dietary protein was determined. Groups varying of ten rats of each age were fed diets containing from 1.53 to 8.05 percent protein as casein supplemented with d-1-methionine for five weeks. The 8.05% protein groups were used as controls. Carcasses were analyzed for total nitrogen and percent protein, fat, and water. Liver composition and total serum protein values were also determined. Two-way analysis of variance and Student's t-tests were used to determine significant age and diet effects. Differences in the response of the two age groups of rats were evident. Eighteen-month-old rats required more protein than the younger animals for the maintenance of body weight. When compared to control values, older rats also needed a higher level of dietary protein to maintain normal total carcass nitrogen. Fatty livers in older rats persisted at higher dietary protein levels than fatty livers in 11-month-old rats, indicating that 18-month-old rats required more protein to support adequate liver lipoprotein synthesis. These findings suggest that 18-month-old rats have a higher dietary protein requirement than 11-month-old rats. High serum protein values for older rats at lower protein levels, however, do not support this conclusion. The increased body weight and proportionally greater fat mass of older animals was a complicating factor in this study. Further research is needed to more clearly define changes in protein requirements during aging. For future studies, using rats of a more advanced age and three, rather than two, different age groups is recommended.Master of Science
12
VITALI, MICHELE. "Dynamics of nanoparticle-protein corona: formation, evolution and insight on protein structure". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/199091.
Testo completoAbstract (sommario):
In tamponi fisiologici, le proteine formano complessi transitori con nanoparticelle (NP), mediati da adsorbimento competitivo alla superficie di quest’ultime, fino alla formazione di una corona proteica stabile (HPC). Lo studio della dinamica d’interazione è fondamentale per ideare terapie basate su NP, in quanto l'HPC determina l'identità biologica delle NP in vivo. La forte affinità tra superfici di NP e proteine può compensare la destabilizzazione che le NP sperimentano in tamponi ad elevata forza ionica, stabilizzandole. Quest’interazione è immediata (soft -non stabile -PC) ma evolve nel tempo (HPC).
Numerosi approcci volti a studiare la composizione dell'HPC hanno raffigurato uno scenario confuso, a causa delle dimensioni delle NP (comparabili con proteine) e della complessità composizionale del siero. Molti di questi studi non offrono un metodo affidabile per determinare la composizione dell'HPC e in alcuni casi sono contraddittori. La scarsa conoscenza della risposta dei nanomateriali in mezzi biologici è un punto chiave di queste controversie. Numerosi parametri, come l’aggregazione, sono sottostimati, ma risultano critici per comprendere la formazione dell'HPC. È necessario quindi sviluppare un protocollo semplice ma efficiente ed affidabile per studiare questi processi.
In questo lavoro si è studiata la formazione di NP-PC con un approccio semplice e attendibile, al fine di determinare composizione e proprietà fisicochimiche dell'HPC oltre alle propriteà strutturali delle proteine adsorbite.
Nella prima parte è studiato l’evoluzione nel tempo del PC su NP di oro 20 nm, come modello di NP metalliche utilizzato in medicina, monitorando evoluzione di proprietà fisicochimiche del PC con spettroscopia UV-Vis, Dynamic Light Scattering, Z-Potential. L’evoluzione dell’HPC proveniente dall'incubazione in siero è confrontata con quella risultante dall'incubazione con solo albumina o IgG, le proteine sieriche più abbondanti. L'evoluzione del PC quando coniugato con una proteina, è inteso come un'impronta digitale dell'adsorbimento di quella specifica proteina. Pertanto, questo confronto suggerisce la composizione finale dell'HPC. La dinamica del PC proveniente dal siero esibisce la dominanza fisicochimica dell'albumina, con poche differenze forse collegate alla presenza di composti minori nell’HPC. L'analisi proteomica conferma il risultato. L'HPC mantiene le sue caratteristiche nel tempo ed esercita un effetto protettivo sul nucleo della NP se introdotte in condizioni di attacco chimico (NaCN e HNO3) che mimano la degradazione metabolica del PC. La proteolisi limitata dell’HPC indica un’alterata metabolizzazione proteica all'interno dell'HCC, probabilmente dovuta ad una sua variazione strutturale.
Nella seconda parte, HPC è studiato su NP di SiO2 di 50 nm, come modello di NP di ossido utilizzato in nanomedicina, utilizzando sia proteine globulari che intrinsecamente disordinate (IDP), con lo scopo di indagare cambiamenti conformazionali indotti dall'interazione con NP. Le IDP esistono in soluzione in un insieme conformazionale, le cui caratteristiche in presenza di NP sono sconosciute. Tre IDP, a-caseina, Sic1 e a-sinucleina sono state analizzate rispetto a lisozima e transferrina (proteine globulari modello). Le struttura nell’HPC è studiata mediante dicroismo circolare e spettroscopia infrarossa a trasformata di Fourier. I risultati indicano che le IDP mantengono il disordine strutturale all'interno dell'HPC, sperimentando minori transizioni conformazionali ma essendo stabilizzate contro variazioni dell’intorno. Le globulari, invece, tendono a perdere la loro struttura ordinata. Le proteine nell'HPC sono visualizzate mediante elettroforesi mentre microscopia elettronica mostra un HPC formato da un singolo strato di molecole proteiche.
Quest'ultima parte apre ampie prospettive sull'uso di NP come agenti che imitano partner molecolari.In complex physiological media proteins form transient complexes with nanoparticles (NPs), mediated by competitive binding between proteins and NP surfaces, leading to the formation of a stable (hard) protein corona (HPC). Understanding the formation and the dynamics of this interaction is crucial for designing NP-based therapies, since HPC determines the biological identity of the NPs in vivo. The strong affinity between NPs surfaces and proteins can compensate the destabilization forces that colloidal NPs experience in high ionic strength media, stabilizing them. This interaction is immediate (soft -non stable –PC) and evolves with time (HPC). Nowadays, different studies regarding HPC composition show contradictory results. The complexity of serum composition, being NP size in the same range of proteins, and lack of reliable methods to determine composition of HPC, are behind these controversies. Several underestimated parameters regarding the response of NPs in physiological media (aggregation, dissolution) are critical determinants to be carefully addressed to better understand the formation of the HPC. In this context, it is necessary to develop simple but efficient and reliable protocols to study these processes. In this work, consequences of NP-PC formation providing a simple and reliable approach for determining both composition and physicochemical characterization of the HPC, and the implication for protein structures, is shown. In the first part, the hardening of the PC on 20 nm AuNPs, as a model case of metallic NP widely used in medicine, was monitored over time by UV-Vis spectroscopy, Dynamic Light Scattering and Z-Potential. Results of the process of HPC formation with only albumin or IgG were compared to results of HPC formation in serum. Time evolution of the NP-PC when conjugated with one protein can be understood as a fingerprint of the adsorption of that specific protein. Thus, the study of the PC evolution in serum provided information about the final composition of the HPC. Results showed similar pattern as when incubated when only albumin. Proteomic analysis confirmed the results. In addition, experiments mimicking the natural metabolic degradations of bioconjugates using etching agents (NaCN and HNO3), indicated that HPC exert protective effect on the NP core. Finally, limited proteolysis experiments indicated an altered metabolization of the protein inside the HPC, which can be related to a protein altered conformation in this adsorbed state. In the second part, HPC was studied on 50 nm SiO2 NPs, as a model case of metal oxide NP widely used in nanomedicine, by using either globular and intrinsically disordered proteins (IDPs), with the aim to investigate conformational changes induced by the interaction with NPs. IDPs exist in solution as conformational ensembles, whose features in the presence of NPs are still unknown. Three IDPs, acasein, Sic1 and asynuclein, were analyzed compared to lysozyme and transferrin (globular proteins model), describing conformational properties inside the HPC by circular dichroism and Fourier-transform infrared spectroscopy. Results indicated that IDPs maintain structural disorder inside HPC, experiencing minor, protein-specific, induced folding and stabilization against further conformational transitions. Oppositely, the analyzed globular proteins displayed the tendency to lose their ordered structure. Finally, the Transferrin-Tb complex, was also used in the HPC formation. The detection of the fluorescent properties of Tb upon HPC preparation is reported. By electrophoresis it was observed all the proteins forming the HPC and electron microscopy showed an HPC of a single layer of protein molecules. This latter part of work opens broad perspectives on the use of NP as agents that mimic macromolecular partners, allowing the comprehension of the effect of different factors affecting the interaction by rational design of NP surfaces.
13
Mazzetti, Scott A. "Akt and ERK activation in human skeletal muscle : dose-dependency of responses to increasing muscle contractions". Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1259313.
Testo completoAbstract (sommario):
Akt activation mediates increases in glycogen synthesis in response to insulin in humans, while extracellular signal-regulated kinase (ERK) activation increases gene transcription and protein translation in response to endurance and resistance exercise. Akt activation increases only in response to intense muscle contractions and during hypertrophy in rats. No study has examined Akt and ERK activation with increasing numbers of intense muscle contractions in humans. Therefore, the primary objectives of this investigation were to determine if Akt activation increases in response to resistance exercise in humans, and to compare the changes in Akt and ERK activation in response to increasing numbers of muscle contractions.Akt and ERK activation were compared in muscle biopsy samples from 7 men before (Pre) and after (Post) knee extension and control protocols using enzyme linkedimmunosorbent assays. Baseline information was obtained including body composition and maximal strength (1-RM). Subjects were familiarized with knee extensions performed at 70% of 1-RM and a specified repetition cadence (2sec up, 2sec down). Once/wk, subjects performed one protocol in random order: 1 repetition (rep), 10reps, 3 sets of l0reps (3x10), or 6min of sitting. Akt activation decreased 42%, while ERK activation increased 108% in response to 3x10 (p<0.05). Akt and ERK activation did not change with 1 and 10reps, and thus their responses were not dose-dependent with resistance exercise in humans. The findings from this study represent the first indication that Akt activation is reduced in response to resistance exercise in human skeletal muscle, possibly to help mediate reductions in glycogen synthesis.Human Performance Laboratory
14
Herring, B. P. "The role of myosin light chain phosphorylation in regulating cardiac contractility". Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375035.
Testo completo
15
Hassan, Mohamed S. A. "Egg protein interactions with phenolic compounds: effect on protein properties". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117210.
Testo completoAbstract (sommario):
Interactions of egg proteins (ovalbumin, conalbumin, egg white proteins, and egg yolk proteins) with selected phenolic compounds (flavone, chrysin, quercetin, and rutin) in aqueous media were examined by electrophoresis and fluorescence spectrophotometry. SDS-PAGE and native-PAGE results showed variable changes on the electrophoretic behaviour of egg white proteins in the presence of quercetin, while conalbumin-phenolic reaction products showed interactions under non-reducing conditions only. Fluorescence quenching technique was used to investigate the nature of egg protein-phenolic interactions and to estimate the effect of glycosylation and hydroxylation of phenolic compounds on the affinity to egg proteins. Stern-Volmer data revealed that the mechanism of egg protein-phenolic interactions is the static quenching and suggest that the diffusion does not play a role in fluorescence quenching in egg protein-phenolic interactions; the binding data analysis suggests that glycosylation and hydroxylation of phenolic compounds lower the affinity to egg proteins. Fluorescence quenching results showed that fluorescence intensity of egg proteins decreased with increasing concentration of phenolics. Enzymatic hydrolysis of egg protein-phenolic products assessed by using trypsin-chymotrypsin mixture and bacterial protease revealed that in vitro egg protein digestion was adversely affected by the interaction of phenolics. Proteins extracted from muffin mixture with added phenolics were investigated by electrophoresis techniques and enzymatic hydrolysis. SDS-PAGE results showed changes in electrophoretic patterns of ovalbumin. In vitro enzymatic hydrolysis of proteins extracted from the muffin was adversely affected by the addition of phenolics.Les interactions de protéines d'œuf (ovalbumine, conalbumine, protéines de blanc d'oeuf, protéines de jaune) avec des composés phénoliques sélectionnés (flavone, chrysine, quercétine et rutine) dans des milieux aqueux ont été examinées par électrophorèse et spectrofluorométrie. Les résultats de native-PAGE et SDS-PAGE ont montré des changements variables sur le comportement électrophorétique des protéines du blanc d'œuf en présence de la quercétine, tandis que les produits de réaction entre conalbumine et phénoliques ont montré des interactions dans des conditions non réductrices seulement. La technique extinction (quenching) de la fluorescence a été utilisé pour étudier la nature des interactions protéines d'oeuf et phénoliques, et pour estimer l'effet de la glycosylation et l'hydroxylation de composés phénoliques sur l'affinité à la protéine d'oeuf. Les données de Stern-Volmer ont révélé en utilisant un quencher « desactivateur » que le mécanisme d'interactions entre la protéine d'œuf et les composées phénoliques est de type électrostatique et suggère que la diffusion ne joue pas un rôle dans l'extinction de la fluorescence en présence d'interactions protéines d'œuf et composés phénoliques. L'analyse des données « binding » soit des liaisons, suggère que la glycosylation et l'hydroxylation des composés phénoliques réduit l'affinité pour les protéines d'oeuf. Les résultats de l'extinction de la fluorescence ont montré que l'intensité de fluorescence des protéines de l'œuf diminue avec l'augmentation de la concentration des composés phénoliques. Les produits d'hydrolyses enzymatiques des complexes protéines d'oeuf-composés phénoliques évaluées suite à une protéolyse par un mélange trypsine-chymotrypsine et de la protéase bactérienne ont révélé que la digestion in vitro des protéines d'oeuf a été affectée négativement par l'interaction des composés phénoliques. Les protéines extraites du mélange à muffins enrichis en composés phénoliques ont été étudiés par des techniques d'électrophorèse et d'hydrolyse enzymatique. Les résultats du SDS-PAGE ont montré des changements dans le modèle électrophorétique de l'ovalbumine. L'hydrolyse enzymatique in vitro des protéines extraites du muffin a été affectée négativement par l'ajout de composés phénoliques.
16
De, Angelis Fabien. "Characterization of proteins involved in RND-driven heavy metal resistance systems of Cupriavidus metallidurans CH34". Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210154.
Testo completoAbstract (sommario):
Les systèmes d’efflux tripartite de type Resistance, Nodulation and cell-Division (RND) sont essentiels dans le maintien de phénotypes de résistance multidrogues et contre les métaux lourds dans nombreuses bactéries Gram-négatives. Le transport de ces composés toxiques hors de la cellule est permis par l’assemblage d’une protéine de type antiporteur cation/proton (unité RND) insérée dans la membrane interne, connectée à une protéine insérée dans la membrane externe, pour former un canal de sorti qui traverse l’entièreté de l’enveloppe cellulaire. Le troisième composant du système, la protéine de type membrane fusion protein (MFP) qui est aussi appelée periplasmic adaptor protein (PAP), est requis pour permettre l’assemblage de tout ce complexe à trois composants. Cependant, les MFPs sont supposées jouer un rôle important et actif dans le mécanisme d’efflux du substrat. Pour mieux comprendre le rôle des MFPs au sein des systèmes d’efflux de type RND, nous avons étudié les protéines ZneB (précédemment appelée HmxB) et SilB, les composants périplasmiques des systèmes ZneCBA et SilABC responsables de la résistance aux métaux lourds chez Cupriavidus metallidurans CH34. Nous avons identifié la spécificité de liaison au substrat de ces protéines, montrant leur capacité à fixer le zinc (ZneB), ou le cuivre et l’argent (SilB). De plus, nous avons résolu la structure cristalline de ZneB à une résolution de 2.8 Å dans la forme apo- et avec un ion zinc fixé. La structure de ZneB possède une architecture générale composée de quatre domaines caractéristiques des MFPs, et la présence du site de coordination au zinc dans une région très flexible à l’interface des domaines β-barrel et membrane proximal. Les modifications structurales que la protéine subit lors de la fixation du zinc on été observée dans le cristal mais aussi en solution, ce qui suggère un rôle actif des MFPs dans le mécanisme d’efflux des métaux, vraisemblablement via la fixation et le relargage de l’ion à l’antiporteur. Les études de sélectivité de transport des antiporteurs ZneA et SilA montre que ces dernières et leurs protéines périplasmiques respectives ont des affinités similaires pour les métaux lourds. De plus, les études de transport ont apportés des arguments en faveur de l’hypothèse de capture cytoplasmique du substrat par l’antiporteur, tandis que la capacité des protéines périplasmiques à fixer les métaux lourds a apporté des arguments en faveur de l’hypothèse de capture périplasmique du substrat par l’antiporteur. Les deux modes de capture pourraient en réalité coexister ;cependant, le débat autour du compartiment cellulaire de capture du substrat par l’antiporteur est complexe et requiert de plus amples efforts afin d’être cerné. / Tripartite resistance nodulation cell division (RND)-based efflux complexes are paramount for multidrug and heavy metal resistance in numerous Gram-negative bacteria. The transport of these toxic compounds out of the cell is driven by the inner membrane proton/substrate antiporter (RND protein) connected to an outer membrane protein to form an exit duct that spans the entire cell envelope. The third component, a membrane fusion protein (MFP) also called periplasmic adaptor protein, is required for the assembly of this complex. However, MFPs are also proposed to play an important active role in substrate efflux. To better understand the role of MFPs in RND-driven efflux systems, we studied ZneB (formerly HmxB) and SilB, the MFP components of the ZneCAB and SilABC heavy metal RND-driven efflux complexes from Cupriavidus metallidurans CH34. We have identified the substrate binding specificity of the proteins, showing their ability to selectively bind zinc (ZneB), or copper and silver cations (SilB). Moreover, we have solved the crystal structure of the apo- and the metal-bound forms of ZneB to 2.8 Å resolution. The structure of ZneB displays a general architecture composed of four domains characteristic of MFPs, and it reveals the metal coordination site at the very flexible interface between the β-barrel and the membrane proximal domains. Structural modifications of the protein upon zinc binding were observed in both the crystal structure and in solution, suggesting an active role of MFPs in substrate efflux possibly through binding and release. The selectivity assays of the antiporter proteins ZneA and SilA demonstrated similar specificities in relation to their cognate MFPs toward heavy metal cations. Moreover, antiporter transport assays provide evidence for cytoplasmic substrate capture by this protein, whereas MFP substrate binding provides evidence for periplasmic substrate capture. Therefore, both modes of capture might co-exist; nevertheless, the substrate capture issue is a complex topic still needing consequent efforts to understand it.Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
17
Razanakolona, Mahita. "Effets anti-inflammatoires de l'inhibiteur dépendant de la protéine Z : intérêt potentiel comme traitement adjuvant du sepsis". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS564/document.
Testo completoAbstract (sommario):
Le choc septique est une défaillance circulatoire aiguë déclenchée par un agent infectieux, entraînant des désordres hémodynamiques, métaboliques et viscéraux, en raison notamment de la libération de cytokines proinflammatoires. Le taux de mortalité est élevé (environ 40 %). L’évolution des sepsis sévères est souvent compliquée par des phénomènes thrombotiques qui résultent en partie de l’activation de la coagulation par les agents infectieux, mais aussi de la libération de Neutrophil Extracellular Traps (NETs) par les polynucléaires neutrophiles. Ainsi, chez ces patients, une coagulation intravasculaire disséminée (CIVD) est souvent observée, caractérisée par un état d’équilibre instable, où co-existent un risque thrombotique et un risque hémorragique, dû à la consommation des facteurs de coagulation.Plusieurs études ont suggéré que l’administration d’antithrombine (AT) ou de Protéine C activée diminuait la mortalité, non seulement en diminuant l’activation de la coagulation, mais aussi en ayant des effets cytoprotecteurs et anti-inflammatoires indépendants de leur activité anti-coagulante. Toutefois, leurs effets cytoprotecteurs nécessitent l’administration de doses élevées, responsables d’hémorragies.L’inhibiteur dépendant de la protéine Z (ZPI), appartient à la superfamille des serpines, comme l’AT, mais n’inhibe que les facteurs Xa (FXa) et XIa (FXIa). L’inhibition du FXa est potentialisée par la Protéine Z (PZ), un facteur vitamine K-dépendant, qui circule dans le plasma lié au ZPI. Dans un modèle en sang total, j’ai observé que le ZPI exerce un effet inhibiteur sur la production de cytokines pro-inflammatoires (IL-6 et TNF-α) en réponse au lipopolysaccharide (LPS). A forte concentration (4 fois la concentration physiologique), l’effet anti-inflammatoire (EAI) du ZPI n’est pas modifié par l’ajout de PZ ou d’héparine non fractionnée, qui majorent l’effet anticoagulant du ZPI. De plus, l’EAI persiste avec un variant de ZPI muté sur son site actif (ZPI Y387A), suggérant que le ZPI possède un EAI indépendant de son activité anticoagulante. In vitro, en sang total, le ZPI augmente précocement la production de CCL-5, une chimiokine ayant des propriétés anti-inflammatoires. Ces observations ont été confirmées dans un modèle d’endotoxinémie in vivo, chez la souris, en injectant par voie intra-péritonéale du LPS. Les souris qui avaient reçu simultanément du ZPI recombinant humain ont un taux plasmatique plus faible d’IL-6 et de TNF α que les souris contrôles et un taux plus élevé de CCL-5 dans le lavage péritonéal.De plus, nous avons mis en évidence, en milieu purifié, que l’élastase neutrophile, une enzyme libérée à la surface des NETs induisait plusieurs clivages du ZPI. Le premier clivage se produit au niveau de la boucle réactive du ZPI, qui perd alors son activité inhibitrice sur les FXa et FXIa. La PZ ne protège pas le ZPI de sa dégradation par l’élastase. La dégradation du ZPI induite par les NETs pourrait participer à leurs propriétés procoagulantes.Enfin, en collaboration avec l’équipe du Service de Réanimation du CHU de Strasbourg, nous avons étudié les variations des taux plasmatiques de PZ et ZPI chez 100 patients atteints de sepsis sévère. Dans les premières 24 heures, nous avons observé une diminution du taux de PZ par rapport à une groupe de sujets sains, et à l’inverse, une augmentation d’environ 2,5 fois du taux de ZPI. Ce taux élevé de ZPI persiste à J3 et J7, alors que le taux de PZ augmente. Les variations de PZ ou ZPI ne sont pas prédictifs de la mortalité à 30 jours ni de l’apparition d’une CIVD.Ces résultats suggèrent que des doses élevées de ZPI (4 fois la concentration physiologique) pourraient constituer un traitement adjuvant du choc septique, en diminuant la production de cytokines pro-inflammatoires, avec un risque hémorragique faible, puisque l’inhibition du FXIa a des activités antithrombotiques dépourvues de risque hémorragiqueSeptic shock is an acute circulatory failure caused by an infectious agent, resulting in hemodynamic, metabolic and visceral disorders, in particular due to pro-inflammatory cytokines. The mortality rate is high (about 40 %). Progression of severe sepsis is often complicated by thrombotic events, in part because of a direct coagulation activation by bacteria, but also because of Neutrophil Extracellular Traps (NETs) released by polymorphonuclear neutrophils. Disseminated intravascular coagulation (DIC) is frequently present in these patients, characterized by an unstable equilibrium, where thrombotic and bleeding risks coexist, due to the consumption of coagulation factors.Several studies suggested that administration of coagulation inhibitors, such as antithrombin (AT) or activated Protein C, decreased mortality, not only by preventing the activation of coagulation, but also through their cytoprotective and anti-inflammatory effects, independent of their anticoagulant activity. However, the cytoprotective effects require the administration at very high doses, leading to a bleeding tendency.The protein Z-dependent protease inhibitor (ZPI) belongs to the serpin superfamily, as AT, but in contrast to AT, inhibits only factors Xa (FXa) and XIa (FXIa) of coagulation. FXa inhibition by ZPI is potentiated by Protein Z (PZ), a vitamin K-dependent factor, which circulates in plasma in a complex with ZPI. In a whole blood model, I observed that ZPI exerts an inhibitory effect on lipopolysaccharide (LPS)-induced pro-inflammatory cytokines production (IL-6 and TNF-α). At high concentration (4 times physiological concentration), ZPI anti-inflammatory effect (AIE) is not modified by PZ or unfractionned heparin, which increase ZPI anticoagulant activity. Moreover, this AIE is still present using a reactive center loop variant of ZPI (ZPI Y387A), suggesting that the AIE of ZPI is independent of its anticoagulant activity. In vitro, in whole blood, ZPI induced an early increased of CCL-5, a chemokine with anti-inflammatory properties. These data are confirmed in vivo in a murine model of endotoxin shock where LPS is injected intraperitoneally. Simultaneously injection of recombinant human ZPI (rhZPI) with LPS led to lower plasma levels of IL-6 and TNF-α than in control mice, whereas higher CCL-5 levels were observed in peritoneal lavages.In addition, using purified proteins, we have shown that neutrophil elastase, an enzyme which decorates NETs, induces several cleavages of rhZPI. A quick and first cleavage is observed on the reactive centre loop of ZPI, inducing a loss of inhibitory activity towards FXa and FXIa. PZ does not protect ZPI from elastase degradation. ZPI proteolysis induced by NETs could contribute to their procoagulant activity.Lastly, in collaboration with the intensive care unit of Strasbourg Hospital, we studied plasma levels of PZ and ZPI in 100 patients with severe sepsis. During the first 24 hours, there was a significant decrease of plasma PZ levels, compared to levels of healthy subjects, whereas an approximately 2.5 times increase was observed for ZPI levels. These high levels of ZPI were still present at D3 and D7, whereas PZ levels regularly increased. Variations of PZ and ZPI levels were not predictive of the 30-day mortality rate, and not associated with DIC development.These results suggest that elevated concentrations of ZPI (4 times physiological concentration) could be an adjuvant therapy to septic shock, by decreasing pro-inflammatory cytokines production, but devoid of bleeding risk, since FXIa inhibition has antithrombotic activity without inducing haemorrhages
18
Schultz-Ascensio, Eliette. "Diffusion d'îlots génomiques de multirésistance aux antibiotiques chez Proteus mirabilis". Thesis, Tours, 2018. http://www.theses.fr/2018TOUR3302/document.
Testo completoAbstract (sommario):
La résistance aux antibiotiques est une menace non négligeable pour la santé publique. Ces résistances peuvent être portées par différents supports dont les îlots génomiques. Il a été démontré que les îlots génomiques Salmonella Genomic Island 1 (SGI1) et Proteus Genomic Island 1 (PGI1) sont des acteurs importants de la multirésistance aux antibiotiques. Quelques variants de SGI1 et PGI1 ont déjà été décrits au sein de l’espèce P. mirabilis. Dans ce contexte, ce projet de thèse se proposait d’approfondir notre connaissance de la situation épidémiologique de la diffusion de SGI1 et PGI1 chez P. mirabilis chez l’homme et l’animal en France, en ce qui concerne la diversité des isolats, mais aussi celles des variants de SGI1/PGI1. En parallèle, une autre volonté a été d’identifier d’autres facteurs et acteurs permettant l’acquisition de gènes de résistances d’intérêt au sein des Morganellaceae (β-Lactamases à Spectre Etendu, céphalosporinase AmpC, Plasmid-mediated Quinolone Resistance...). Au final, cette étude a permis en outre de révéler les premiers cas de SGI1 et PGI1 chez P. mirabilis chez l’animal en France. De nouveaux variants de SGI1 ont également été mis en évidence. Et pour la première fois, SGI1 a été décrit chez M. morganii, une autre espèce d’entérobactérieThe antibiotic resistance is a major treat for public health. These resistances can be hold by different element and genomic islands are one of them. Salmonella Genomic Island 1 (SGI1) and Proteus Genomic Island 1 (PGI1) are important genetic elements for the antibiotic resistance. A few SGI1 and PGI1 variants were already described in P. mirabilis. It is in this context that this thesis project aimed to improve our knowledge about the epidemiological spread of SGI1 and PGI1 in P. mirabilis in humans but also in animals in France (diversity of isolates and SGI1/PGI1 variants). Moreover, another wish was to identify other factors and actors for the acquisition of antibiotic resistance in the Morganellaceae tribe (Extended-Spectrum β-Lactamases, AmpC cephalosporinase, Plasmid-mediated Quinolone Resistance…). Finally, this study revealed the first cases of SGI1 and PGI1 in P. mirabilis in animals in France. New SGI1 variants were also described. And for the very first time, SGI1 was found in M. morganii, another entrobacterial species
19
Onaolapo, Josiah A. "The effect of R-plasmid RP1 on the properties of Proteus mirabilis". Thesis, Aston University, 1986. http://publications.aston.ac.uk/12455/.
Testo completoAbstract (sommario):
A clinical isolate of Proteus mirabilis containing R-plasmid RP1 (R+ cells), grown in both iron- and carbon- limited chemically defined media in mixed culture with plasmid-free (R- cells), did not disappear as expected, due to adherence of R+ cells to the wall of the chemostat vessel. Plasmid RP1 promoted adherence to glass and to medical prostheses. The hydrophobicity and surface charge of R+ cells were different from those of R- cells and both factors may contribute to the adherence of R+ cells to surfaces. The mode of cultivation of the cells, whether batch or continuous culture, were also found to affect the result. Antibodies raised against homologous cells increased the surface hydrophobicity of both R+ and R- cells and eliminated the differences between them. Results for surface hydrophobicity varied with the method used for measuring it. R+ cells were more sensitive than R- cells to tbe bacteridical action of normal serum and whole blood and to phagocytosis as measured by chemiluminescence. No clear differences were revealed in the protein antigens of R+ and R- cells by both SDS PAGE gels and immunoblots reacted with homologous antibodies. However, lectins revealed differences in the sugars exposed on the cell surfaces. Chemical analysis of R&43 and R- cells also revealed differences in the content of 2-keto-3-deoxy-D-manno-2-octulosonate, lipopolysaccharide and total fatty acids, when cells were grown in media containing added iron; however, no qualitative differences in the lipopolysaccharide were found. Removal of iron from the medium was found to have considerable effects on the chemical structure of R+ cells but not of R- ones. Adhesion to prostheses and to leucocytes is discussed in the light of the results and the clinical relevance outlined with respect to the initiation of infection and the association of virulence with antibiotic resistance.
20
Chao, Sheng-Hao. "Heat Shock Proteins in Ascaris suum". Thesis, University of North Texas, 1995. https://digital.library.unt.edu/ark:/67531/metadc279311/.
Testo completoAbstract (sommario):
Ascaris suum were exposed to a number of stressors, including heavy metals and both high (40°C) and low (18°C) temperatures. The 70kD and 90kD heat shock proteins (HSPs) in the different A. suum tissues were analyzed by Western blot and quantitated by Macintosh Image Program.
21
Haus, Jacob M. "AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent protein kinase II (CAMKII) activation in exercising human skeletal muscle". Virtual Press, 2004. http://liblink.bsu.edu/uhtbin/catkey/1294245.
Testo completo
22
Johansson, Ingegerd. "The effect of malnutrition on saliva composition and caries development". Doctoral thesis, Umeå : [s.n.], 1986. http://catalog.hathitrust.org/api/volumes/oclc/14125355.html.
Testo completo
23
Ali, Haroon. "Protein-phenolic interactions in food". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32748.
Testo completoAbstract (sommario):
Our objective was to investigate the mode of interaction between selected food proteins and phenolic compounds. Bovine serum albumin (BSA), bovine beta-lactoglobulin, and soybean glycinin were used with the following phenolic compounds; 3,4,5-trihydroxybenzoic acid (gallic acid), 3,4-dihydroxy cinnamic acid (caffeic acid), p -hydroxycinnamic acid (courmaric acid), and 5,7-dihydroxy 4-methoxy isoflavone (biochanin A). The interaction was investigated using incubation temperatures of 35°, 45° and 55°C at pH 5, 7 and 9. Native and SDS-polyacrylamide gel electrophoresis (PAGE), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy were used to identify protein-phenol interactions. Certain phenolic compounds combined with BSA and prevented protein aggregation. In general, the thermal stability of the proteins increased as a result of interaction with phenolic compounds; the most pronounced effect was observed with beta-lactoglobulin in the presence of gallic acid at pH 7. The interaction of the phenols with the proteins resulted in changes in protein secondary structure. (Abstract shortened by UMI.)
24
Schersch, Kathrin Brigitte. "Effect of collapse on pharmaceutical protein lyophilizates". Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-120481.
Testo completo
25
Hadizadeh, Shirin. "The effect of osmolytes on protein folding". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/30503.
Testo completoAbstract (sommario):
Living cells are composed of a variety of biological macromolecules such as nucleic acid, metabolites, proteins and cytoskeletal filaments as well as other particles. The fraction of the cellular interior volume that is taken by these biomolecules is about 30%, leading to a highly crowded environment. Biomolecules present in an extremely dense environment inside a cell have a completely different set of kinetic and thermodynamic behavior than in a test tube. Therefore comprehending the effect of crowding conditions on biological molecules is crucial to broad research fields such as biochemical, medical and pharmaceutical sciences. Experimentally, we are able to mimic such crowded environments; which are of more physiological relevance, by adding high concentrations of synthetic macromolecules into uncrowded buffers. Theoretically, very little attention has been paid to the effects of the dense cellular cytoplasm on biological reactions. The purpose of this work is to investigate analytically the effects of crowding agents on protein folding and stability. We present a new parameter as the measure of the polymer size, which will substitute the traditional measurements of the radius of gyration of the polymer and the end to end distance of a polymeric chain. Using this quantity we derive an expression for the free energy of the polymer which can easily be generalized to provide the free energy of a protein. This mechanism enables us to study the effect of crowding on folding and stability of a protein. The stabilization effects of the crowding particles depend on the concentration and the size of the crowders and also the type of the crowding particles that are present in the system. In our calculations the type of the crowders is controlled by the energetic parameter between the protein and surrounding macromolecules.
26
Foord, Rachel Lucy. "The effect of osmolytes on protein stability". Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244276.
Testo completo
27
Rwere, Freeborn. "Resonance Raman studies of isotopically labeled heme proteins". [Milwaukee, Wis.] : e-Publications@Marquette, 2009. http://epublications.marquette.edu/dissertations_mu/22.
Testo completo
28
Lopez, Murielle. "The Effect of Hydration on Enzyme Activity and Dynamics". The University of Waikato, 2008. http://hdl.handle.net/10289/2360.
Testo completoAbstract (sommario):
Water has long been assumed to be essential for biological function. To understand the molecular basis of the role of water in protein function, several studies have established a correlation between enzyme activity and hydration level. While a threshold of hydration of 0.2 h (grams of water per gram of dried protein) is usually accepted for the onset of enzyme activity, recent works show that enzyme activity is possible at water contents as low as 0.03 h (Lind et al., 2004). Diffusion limitation in these experiments was avoided by monitoring enzyme-catalyzed hydrolysis of gas-phase esters. However, since water is also a substrate for the enzyme used in these experiments, they cannot be used to probe the possibility of activity at zero hydration. However, the pig liver esterase and C. rugosa lipase B are able to catalyse alcoholysis reactions in which an acyl group is transferred between an ester and an alcohol. Therefore, by following this reaction and using a gas phase catalytic system, we have been able to show that activity can occur at 0 g/g. These results led to the question of the accuracy of determinations of very low water concentrations; i.e., how dry is 0 g/g? Although gravimetric measurements of the hydration level do not allow us to define the anhydrous state of the protein with sufficient sensitivity, using 18O-labeled water, we have been able to quantify the small number of water molecules bound to the protein after drying, using a modification of the method of Dolman et al. (1997). Testing different drying methods, we have been able to determine a level of hydration as low as 2 moles of water per mole of protein (equivalent to 0.0006 h in the case of pig liver esterase) and have shown that in the case of the pig liver esterase, activity can occur at this hydration level. At the molecular level, if the hydration level affects activity, we can expect an effect on the protein dynamics. Neutron scattering spectra of hydrated powders, for instance, show that diffusive motions of the protein increase with the hydration (Kurkal et al., 2005) To address the question of the protein motions involved in the onset of enzyme activity at low hydration, we performed neutron scattering experiments on a pico-second time scale on dried powders. Preliminary results show a dynamical transition at hydration levels as low as 3 h. Molecular dynamic simulations have also been used in this study to access the dynamics of the active site. Overall, the results here show that pig liver esterase can function at zero hydration, or as close to zero hydration as current methods allow us to determine. Since the experimental methodology restricts this work to a small number of enzymes, it is unlikely that it will ever be possible to determine if all enzymes can function in the anhydrous state: however, the results here indicate that water is not an obligatory requirement for enzyme function.
29
Calimport, Stuart. "Technologies to study protein oxidation in ageing : investigating the effect of protein oxidation on protein function". Thesis, Aston University, 2017. http://publications.aston.ac.uk/30399/.
Testo completoAbstract (sommario):
Protein oxidation can cause aggregation, fragmentation, and affect enzymatic activity and binding partner interactions. Protein oxidation is implicated in a range of agerelated pathologies including neurodegeneration and cancer. The VHR and PTEN phosphatases studied are sensitive to oxidation and regulated by protein-protein interactions. PTEN acts by dephosphorylating phosphatidylinositol (3,4,5)-triphosphate, negatively regulating the Akt pathway as part of a signalling control network that can protect against apoptosis, and is involved in the regulation of cell fate regulation and cancer. VHR is involved in neural development and cancer. A technology workflow for detecting protein oxidation and to correlate oxidative modifications to enzymatic activity and protein-protein interaction was developed; which may contribute towards the advancement of fundamental science as well as potential therapeutic and biomarker target identification in proteins. The technology platform consists of the mass spectrometric technique MS2 to detect, validate, map and quantify oxidative modifications. The technology workflow consists of enzymatic activity assays to correlate modification with changes in activity, targeted MS2 and statistical analysis. The fundamental and distinct contribution to knowledge in this thesis is a systematic mapping of protein oxidative modifications over a range of oxidants and concentrations of hypochlorous acid (HOCl), 3-morpholino-sydnonimine (sin-1) and tetranitromethane for VHR (vaccinia H1 related) and PTEN (phosphatase and tensin homolog on chromosome 10), including modification identification including active site residues and putative binding domain, mapping the relative abundances of those modification and statistically correlating them to changes in enzymatic activity. Additional contributions to knowledge have been i) the nonspecificity and complexity of oxidation profiles and oxidant damage of nitrating agents, that have largely been proposed to be specific without substantial oxidative capacity and ii) expanding the known interactome of VHR (vaccinia H1 related) through array and co-immunoprecipitation.
30
Nwanosike, Quinta M. "Effect of divalent cations and solubilizers in apoferritin and gamma D-crystallin solutions nucleation, crystallization and light scattering studies /". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31736.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Ronald Rousseau; Committee Co-Chair: Athanassios Sambanis; Committee Member: Amyn Teja; Committee Member: Athanasios Nenes; Committee Member: Ingeborg Schmidt-Krey. Part of the SMARTech Electronic Thesis and Dissertation Collection.
31
Yee, Nick. "The proteus effect : modification of social behaviors via transformations of digital self-representation /". May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Testo completo
32
Misra, Rajeev. "Studies on the TolC protein of Escherichia coli K-12 and its effect on OmpF expression". Title page, table of contents and abstract only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm678.pdf.
Testo completo
33
WIDELITZ, RANDALL BRUCE. "HEAT SHOCK PROTEIN SYNTHESIS AND THERMOTOLERANCE EXPRESSION IN RAT EMBRYONIC FIBROBLASTS (HYPERTHERMIA, GENE REGULATION)". Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183851.
Testo completoAbstract (sommario):
In response to a variety of hyperthermic treatments, rat embryonic fibroblasts synthesize heat shock proteins (hsps), including those with molecular weights of 68,000 (hsp 68), 70,000 (hsp 70) and 89,000 (hsp 89). Hyperthermic stresses, which produce the hsps, also cause expression of thermotolerance. The dependence of thermotolerance expression on hsp synthesis was investigated in this mammalian cell line under different heating conditions. Temperature shift experiments showed that hsp synthesis and thermotolerance expression were dependent not only on the absolute hyperthermic temperature, but also on the difference between the initial incubation temperature and the hyperthermic temperature. Small temperature differences which produced no cell killing did not cause detectable synthesis of hsp 68. Increasing the difference of the initial and hyperthermic temperatures reduced cell survival and increased the synthesis of hsp 68. Thermotolerance could be expressed by surviving cells following an initial heat stress even when both heat shock and general protein synthesis were inhibited. Cells exposed to cycloheximide were heated, incubated at their initial temperature for six hours and reheated in the presence of the drug. The inhibitor was then removed and the cells plated for colony formation. The hsps were expressed during this latter incubation period. The regulation of hsp 70 in rat fibroblasts was investigated next. Hsp 70 synthesis rates correlated with the amount of hsp 70 encoding mRNA. The time course of heat shock synthesis and general protein synthesis recovery were each dependent on the duration of the heat stress. Inhibiting protein synthesis with cycloheximide resulted initially in the accumulation of the RNA encoding hsp 70 but did not effect the normal turnover of this RNA species. The conclusions based on these findings are that thermal survival adaptation can be expressed in the absence of hsp 68 synthesis. Hsp 68 is expressed by cells that will ultimately die (see Chapter 2). The hsps do not appear to protect cells against subsequent heat stress. They may function in a repair capacity (see Chapter 3). Hsp 70 expression is primarily regulated by transcription in Rat-1 cells. Hsp 70 does not act to regulate its own turnover (see Chapter 4).
34
King, P. "Branched chain amino/keto acid supplementation following severe burn injury". Thesis, University of Salford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376875.
Testo completo
35
Wilkinson-White, Lorna. "Effects of metal ions upon the transthyretin amyloid formation pathway". Thesis, The University of Sydney, 2008. https://hdl.handle.net/2123/28132.
Testo completoAbstract (sommario):
Transthyretin (TTR) is a 56 kD homotetrameric plasma protein, with each monomer composed
of 8 B-strands termed A-H. The main function of transthyretin is the transport of retinol
binding protein and thyroxine, however it is also associated with two types of amyloid disease.
The WT form of the protein forms amyloid leading to senile systemic amyloidosis (SSA),
which occurs in 25% 0f the population over the age of eighty. There are also >70 separate
point mutations in TTR associated with familial amyloid polyneuropathy (FAP), which has a
varied symptomology dependent upon the mutation. The most common is the V30M mutation,
which is prevalent in Portuguese kindreds, while the L55P mutation is the most virulent, often
causing death by ~20 years of age. There are also several protective mutations, such as T119M,
where compound heterozygotes such as V30M/Tl 19M show an absence of disease.
Metal ions have been implicated in amyloid formation by a number of proteins, such as AB,
PrP and a-synuclein, which are associated with Alzheimer’s, Creutzfeld-Jacob and Parkinson’s
Disease respectively. Given the strong association between metal ions and these prominent
amyloid diseases, it was believed there was sufficient precedent to examine their role in
transthyretin amyloid formation. A wide variety of metal ions were initially tested for their
effects upon WT, T119M, V30M and L55P TTR. Cu(II) and Zn(II) were shown to most
strongly enhance both the aggregation and amyloid formation of L55P, and to a lesser extent
V30M. They did not effect either WT or T119M. Histidine residues have been previously
implicated in metal ion binding by a number of amyloidogenic proteins. A possible role for
these residues in enhancement of LSSP amyloid formation was explored by the creation of an
L55P/H56G mutant. HisS6 was selected for mutation due to its being adjacent to the L55P
mutation. It appeared that histidine residues did play a role in amyloid formation, with a
significant reduction in both aggregation and amyloid formation observed in the absence of
Hi556.
36
Alla, Victoria Martin. "High Mobility Group Protein 1 (HMGB1) And Its Role As A Global Transcription Regulator In Response To Temperature Fluctuations In The Annual Killifish Austrofundulus limnaeus". PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/239.
Testo completoAbstract (sommario):
As a study organism, annual killifish (Austrofundulus limnaeus) provide a well suited study system for examining the effects of environmental temperature fluctuations at the cellular level. A. limnaeus persist in the harsh high desert climate of the Maracaibo Basin, Venezuela where they live in small, ephemeral freshwater pools. Temperatures in these waters can vary as much as 20 degrees C daily and reach maximums of over 40 degrees C due to the semi-arid climate. Previous cDNA microarray studies on killifish revealed the mRNA pattern for High Mobility Group Protein 1 (HMGB1) to be strongly affected by temperature perturbations. Specifically, peaks in hmgb1 transcript abundance were negatively correlated with temperature during temperature cycling, and experienced over a 10 fold difference in expression in response to the temperature cycle. Using the same temperature cycling experimental setup, this study's aim was three-fold: (1) to characterize the total amount of HMGB1 protein in adult male killifish livers, (2) to describe the subcellular localization of the HMGB1 protein in adult male killifish livers and (3) to sequence the 5' upstream region of the hmgb1 gene to identify possible stress responsive elements. We detected no significant difference in total HMGB1 protein levels as a consequence of temperature cycling. The data for subcellular localization of HGMB1 protein do not support a strong change in subcellular localization of the protein in response to temperature cycling; most of the HMGB1 protein is found in the cytoplasmic compartment in liver tissue. Although overall patterns of subcellular localization did not change significantly, we found a significant difference between nuclear HMGB1 protein levels in temperature cycled fish versus control (constant temperature) fish. This could suggest a muting of the natural translocation of HMGB1 into the nucleus observed in control fish at around 9:00 at night. Finally, the upstream region of the hgmb1 gene does reveal a number of putative stress responsive transcription factor binding sites.
37
Briggs, Geoffrey Shaw. "Folding and stability studies on papain and the effect of recombinant papain pro fragment". Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281755.
Testo completo
38
Bourassa, Hélène. "Membrane proteins and cold acclimation in alfalfa". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56916.
Testo completoAbstract (sommario):
Membrane proteins specific to cold acclimation were studied in alfalfa (Medicago falcata L. cv Anik) seedlings and cell cultures. They were identified following separation on polyacrylamide gels and localized as far as possible to specific membranes by fractionation on continuous sucrose gradient and analysis of marker enzyme assays.With cold acclimation, certain membrane proteins from seedlings showed subtle changes (mainly increases) in their steady-state amount and in their net synthesis rate. Most of these changes were in proteins with molecular weights below 100 kDa and were associated with light fractions of the sucrose gradient, favoring a Golgi, endoplasmic reticulum or tonoplast location for the proteins. Preliminary work done on membrane proteins from cell cultures showed more pronounced changes with cold acclimation. Most of the changes were in proteins with molecular weights below 100 kDa and were associated with heavy fractions of the sucrose gradient. Since they are easier to harvest and to manipulate, cell cultures appear to be the better system to use in future studies.
39
Wagstaff, Marcus James Dermot. "The neuroprotective effect of the heat shock proteins". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267150.
Testo completo
40
Payne, Erin J. "The Effect of HACE1 on RAR Protein Stability". Master's thesis, Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/153451.
Testo completoAbstract (sommario):
Microbiology and ImmunologyM.S.
All-trans retinoic acid (RA), as a ligand for retinoic acid receptors (RAR) and retinoid X receptors (RXR), modulates their transcriptional activity. The AF-1 and AF-2 domains mediate the transcriptional activity. The ligand dependent activation of the AF-2 domain by RA is well understood to involve chromosome decompaction in the presence of ligand with the aid of coactivators. The mechanism of the ligand independent action of the AF-1 domain is less clear. The AF-1 domain of RARs may be regulated by interacting proteins such as HACE1. In vitro and in vivo studies in our lab have shown that HACE1 interacts with RARα1, - β1, -β2, -β3, and -γ1 at the variable AF-1 domain. Transactivation studies have shown that HACE1 represses RA dependent transcriptional activity of RARγ1, but not RARβ3 and RARα1. Our original hypothesis proposed that HACE1 represses RAR transcriptional activity by inhibiting RA-dependent degradation of RARs. Current data confirms previous observations that the half life of RARβ3 is shortened in the presence of RA, compared to a vehicle control. Protein stability assays show that HACE1 does not have an effect on degradation of RARβ3 and RARγ1; however, it increases the ligand independent degradation of RARα1.This data suggests the A/B domain of RARγ1 recruits HACE1 for binding which results in transcriptional repression. Also, in a separate mechanism, the A/B domain of RARα1 binds to HACE1 which then accelerates its degradation in a ligand independent manner. The mechanisms behind these novel roles of HACE1 will need to be studied further and may help in understanding the method of AF-1 transcactivation function.
Temple University--Theses
41
Leblanc, Rosanne. "Protein synthesis and drought stress in two rapeseed cultivars". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60487.
Testo completoAbstract (sommario):
Desiccation effects on rate and pattern of protein synthesis in Brassica napus (cv westar) and Brassica juncea (cv cutlass) have been examined. Results showed that while the rate of water loss was similar in the two species, the inhibition of amino acid incorporation was greater in B. napus than B. juncea at any given level of desiccation. Electrolyte leakage increased with the degree of desiccation and was greater in B. napus than in B. juncea. In both, the increase in leakage was much sharper after 12 hours of desiccation. Quantitative changes in patterns of boiling-stable protein synthesis due to desiccation stress were observed. The control level of protein radioactivity which was boiling-stable in B. napus was 16.16% and 19.96% for B. juncea. After desiccation, the percentage of boiling-stable radioactivity increased to 23.30% for B. juncea and 16.63% for B. napus. In vitro translation of total RNA indicated that desiccation alone does not induce the synthesis of new mRNA species in either cultivar, but it may change the translation pattern resulting in different levels of abundance of proteins.
42
Falconer, Robert J. "The effect of electrolytic lesion and neural implants on glial fibrillary acidic protein expression in the rat spinal cord". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/28983.
Testo completoAbstract (sommario):
This thesis assessed the suitability of unilateral, electrolytic lesions as a model of spinal cord damage and repair in the adult rat. This type of lesion resulted acutely in localized damage in the upper motor neuron at the L2-L3 level of the spinal cord. Minimal acute damage to ascending sensory pathways was indicated by preserved somatosensory evoked potentials elicited by stimulation of the tibial nerve.
Immediately after lesion generation one of several substrates was injected into the lesion cavity. These substrates were saline buffer, liquid collagen solution, foetal spinal cord cells from 14 day old rat embryos, and a mixture of collagen and E 14 foetal spinal cord cells. The 4 groups were compared for functional recovery over 3 months using the inclined plane test and a Tarlov movement scale. After sacrifice, the tibialis anterior muscles were dissected and weighed to assess atrophy due to lower motor neuron injury. After removing and embedding the spinal cords in paraffin, transverse and longitudinal sections were taken for cytoarchitectural investigation. Cresyl violet was used to indicate Nissl substance, Luxol fast blue stained for myelin and anti - glial fibrillary acidic protein (GFAP) antibody revealed the expression of GFAP in the cord sections.
Chronic electrolytic lesions were characterized by the highly variable degree of cavitation, demyelination and macrophage infiltration that was present. There was no significant performance deficit on the inclined plane test in any of the lesioned groups when compared to unoperated animals. The tibialis muscles from all groups were of normal weight, indicating that the lower motor neurons were not significantly damaged by the lesions used. There was, however, a marked decrease in the number of GFAP reactive astrocytes in the lesioned animals when compared to unlesioned controls (P < 0.01, Wilcoxon test). Moreover, this reduction of GFAP - like immunoreactivity was not prevented by implants of foetal neurons, collagen or foetal neurons suspended in collagen. Possible explanations for the reduced GFAP - like immunoreactivity seen in all electrolytically lesioned cords are discussed.Medicine, Faculty of
Cellular and Physiological Sciences, Department of
Graduate
43
Carrithers, John A. "Effects of post-exercise carbohydrate-protein feedings on muscle glycogen restoration". Virtual Press, 1999. http://liblink.bsu.edu/uhtbin/catkey/1133741.
Testo completoAbstract (sommario):
The purpose of this investigation was to determine the effects of post-exercise carbohydrate-protein feedings on muscle glycogen restoration following exhaustive cycle ergometer exercise. Seven male collegiate cyclist (age=25.6±3.3y, ht.=180.9±8.5cm, wt.=75.4±10.7kg, VO2max=4.20±0.4 1•miri 1) performed three trials, each separated by -lwk, 1) 100% (x-D glucose (CHO), 2) 70% carbohydrate-20% protein-10% fat (CHOPRO), and 3) 86% carbohdyrate-14% amino acid (CHO-AA). All feedings were eucaloric, based upon 1.0 g•kgb.W.'1•hr"1 of carbohydrate, and administered every half hour during a four hour muscle glycogen restoration period in an 18% wt./vol. solution. Muscle biopsies were obtained immediately and four hours post exercise. Following the exhaustive exercise and every half hour for four hours a blood sample was drawn. Muscle glycogen concentrations increased 53%, 47%, and 57% for the CHO, CHO-PRO, and CHO-AA feedings, respectively, however no differences among the feedings were apparent in muscle glycogen restoration. The plasma glucose and insulin concentrations demonstrated no differences throughout the restoration period among the three feedings. These results suggest that muscle glycogen restoration does not appear to be enhanced with the addition of either protein or amino acids to an eucaloric carbohydrate feeding following an exhaustive cycle exercise. However, it appears that if adequate amounts of carbohydrates are consumed (greater than 0.70 g•kgb,W,."'•hf' carbohydrate) following exhaustive exercise, maximal muscle glycogen restoration occurs.School of Physical Education
44
Brinck, Kajsa. "Ultraljuds effekt på bakterier : Studie av ultraljuds effekt på bakterier vid olika temperaturer och frekvenser av ultraljud". Thesis, Umeå universitet, Biomedicinsk laboratorievetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-58622.
Testo completo
45
Ott-Reeves, Ellen (Ellen Theresa). "In Situ Hybridization of 70 kD Heat Shock Protein mRNA in a Rat Model of Ethanol Self-Administration". Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc332564/.
Testo completoAbstract (sommario):
Sucrose fading was used to initiate self-administration of ethanol on an FR4 schedule in male Fischer 344 rats. Rats showed low response rates for ethanol alone. After administration of liquid diet containing ethanol, ethanol intake increased over levels prior to administration of the liquid diet. In situ hybridization compared mRNA for the inducible or constitutive 70 kD heat shock proteins in ethanol and nonethanol rats. Both inducible and constitutive mRNAs were found in nonethanol and ethanol tissues. In peripheral organs, radiolableling was higher in ethanol tissue. In brain regions, nonethanol tissues showed higher radiolabeling.
46
Chotikatum, Sucheera [Verfasser]. "The effect of cytokines and involvement of ER stress on intestinal epithelial cell polarity, protein folding and expression of intestinal proteins / Sucheera Chotikatum". Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2017. http://d-nb.info/1150170786/34.
Testo completo
47
Apetri, Constantin Adrian. "Folding of the Prion Protein". Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1080747299.
Testo completo
48
Love-Gregory, Latisha Debrett. "Investigation of the origin of the Y393N allele in old order mennonite and non-mennonite maple syrup urine disease patients : analysis of the branched chain [alpha]-keto acid dehydrogenase complex E1[alpha] gene /". free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3012999.
Testo completo
49
Bourron, Olivier. "Effet de l’AMP activated protein kinase sur la lipolyse dans l’adipocyte humain". Paris 6, 2012. http://www.theses.fr/2012PA066150.
Testo completoAbstract (sommario):
L’AMP-activated protein kinase (AMPK) joue un rôle majeur dans la régulation du métabolisme énergétique. L’AMPK stimule les voies cataboliques et inhibe les voies anaboliques. Pour approfondir les mécanismes par lesquels l’AMPK contrôle l’homéostasie énergétique, nous avons exploré son rôle dans la régulation de la lipolyse adipocytaire humaine. Dans l’adipocyte murin, l’AMPK inhibe la lipolyse. Comme les biguanides et les thiazolidinediones activent cette enzyme, nous avons testé l’hypothèse que ceux-ci pourraient avoir un effet anti-lipolytique dans l’adipocyte humain. Pour répondre à cette question, les adipocytes, obtenus chez des patients bénéficiant d’une plastie abdominale, ont été incubés avec différents agents lipolytiques (isoprénaline et peptide atrial natriuretique/ANP) en présence ou non de biguanides ou de thiazolidinediones. Dans l’adipocyte humain, ces antidiabétiques activent l’AMPK et inhibent la lipolyse induite par l’isoprénaline et l’ANP de 30 à 40%, probablement par l’inhibition de la translocation de la lipase hormono-sensible à la gouttelette lipidique. La stimulation de la lipolyse induit par ailleurs l’activation de l’AMPK. Nous avons montré pour la première fois dans l’adipocyte humain que les biguanides et les thiazolidinediones activent l’AMPK, inhibant ainsi la lipolyse induite par l’isoprénaline et l’ANP. Par ailleurs, les agonistes adrénergiques ainsi que l’ANP stimulent l’activité AMPK via l’augmentation du rapport AMP/ATP, lié à l’activation des acides gras en acyl-CoA. L’AMPK pourrait être utilisée pour restreindre de manière pharmacologique la libération d’acides gras dans la circulationAMP-activated protein kinase (AMPK) plays a key role in regulating energy metabolism. AMPK switches-on catabolic pathways and switches-off anabolic pathways. In order to understand further how AMPK controls energy homeostasis, we have investigated its role in the regulation of human adipose tissue lipolysis. In rodent adipocytes, activated AMPK reduces the lipolytic rate. As metformin and thiazolidinediones activate this enzyme, we tested the hypothesis that they could have an anti-lipolytic effect in human adipocytes. Adipocytes, obtained from individuals undergoing plastic surgery, were isolated and incubated with lipolytic agents (isoprenaline, atrial natriuretic peptide/ANP) and biguanides or thiazolidinediones. Biguanides and thiazolidinediones activated AMPK and inhibited lipolysis induced by isoprenaline and ANP by 30-40%, at least in part by inhibiting hormone-sensitive lipase translocation to the lipid droplet. Inhibition of AMPK by compound C precluded this inhibitory effect on lipolysis. Stimulation of lipolysis also induced an activation of AMP-activated protein kinase concomitant with a drop in ATP concentration. We show for the first time in human adipocytes that biguanides and thiazolidinediones activate AMP-activated protein kinase, thus counteracting lipolysis induced by lipolytic agents. In addition, induction of lipolysis increases AMPK activity, because of an increase in the AMP/ATP ratio, linked to activation of some of the released fatty acids into acyl-CoA. AMPK activation could represent a physiological means of avoiding a deleterious drain of energy during lipolysis but could be used to restrain pharmacological release of fatty acids
50
Jung, Seung-Yong. "The Vroman effect: a molecular level description of fibrinogen displacement". Texas A&M University, 2003. http://hdl.handle.net/1969.1/1577.
Testo completoAbstract (sommario):
Investigations of specific and nonspecific interactions of biomolecules at liquid/solid interfaces are presented. To investigate specific multivalent ligand-receptor interactions, bivalent antibodies and haptens bound to solid supported membrane were used as models for ligand-receptor coupling. Novel microfabrication strategies, which included spatially addressed bilayer arrays and heterogeneous microfluidic assays, in conjunction with total internal reflection microscopy, was employed to achieve this goal. These high throughput techniques allow thermodynamic data of binding interactions to be acquired with only a few microliters of analyte and superior signal to noise. The results yield both the first and second dissociation constant for bivalent IgG antibodies with membrane bound hapten molecules. Studies were conducted both as a function of hapten density and cholesterol content in the membrane.
Another research area of this dissertation is the molecular level description of nonspecific adsorption and displacement of the model protein, fibrinogen, onto hydrophilic surfaces. Techniques such as atomic force microscopy, immunochemical assays, fluorescence microscopy, and vibrational sum frequency spectroscopy were employed to probe this system. The results demonstrate that the protein's αC domains play the critical role. When fibrinogen is adsorbed to a hydrophilic surface via these moieties, its displacement rate in the presence of human plasma is approximately 170 times faster than when these domains are not in direct surface contact. Even more significantly, spectroscopic studies show evidence for highly aligned Arg and Lys residues interacting with the negatively charged substrate only when the αC domains make direct surface contact. The interfacial ordering of these residues appears to be the hallmark of a weak and labile electrostatic attraction between the substrate and the adsorbed macromolecule.