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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
681

Evaluación de varias fuentes de proteína vegetal en dietas para camarón Litopenaeus vannamei

MOLINA POVEDA, CESAR 05 May 2016 (has links)
[EN] The present study was designed to evaluate in independent trials the effect of replace protein fishmeal (HP) by four plant sources, lupine (Lupinus mutabilis Sweet), corn gluten (CGM), amaranth (Amaranthus caudatus L.) and quinoa (Chenopodium quinoa) on the growth of juvenile shrimp Litopenaeus vannamei. For this four sets of diets were developed. The first two containing 35% protein and 11% lipids were prepared to replace the 0, 25, 50, 75 and 100% of the protein from HP by protein lupine (LKM) or CGM. The other two series of isoproteic (30%) and isolipidic (9.5%) diets were formulated to replace 0, 15, 25, 35 and 45% protein HP by protein amaranth and quinoa. Only the contents of corn starch and fish oil were varied to maintain constant levels of protein and lipid in all the experimental diets. All diets had squid meal to provide attractability. Depending on the test conducted eight (LKM and CGM) or seven (amaranth and quinoa) juveniles of about 1g were stocked randomly in aquariums (44 m-2 or 39 m-2) 50 L equipped with a flow-through water system using full-strength seawater. Six aquariums (replicates) were assigned to each of the treatments in a completely randomized design. The shrimp were fed ad libitum twice a day for about eight weeks. At the end of the growth trial, shrimp were fed experimental diets containing 0.5% of chromium oxide. Overall survival in the study was higher than 74% and did not change significantly (p>0.05) when HP was replaced partially or completely by each of the sources evaluated. The results of this study showed that LKM can replace 50% of the protein of HP without significantly (p>0.05) reducing growth (6.7-7.0 g final weight). LKM inclusion in any of the tested levels resulted in a significantly (p<0.05) reduced the apparent digestibility of dry matter (ADMS) and apparent digestibility of crude protein (ADPC) of the feed. The gradual increase of CGM in diets produced a significant (p<0.05) decrease of shrimp final weight (5.9 to 3.2 g) and growth rate (2.7 to 1.7% d-1) compared to those fed CGM 0 (7.1 g and 3.0% d-1). Feed Conversion Factor (FCA) was also significantly (p<0.05) affected by CGM level, diets CGM50, CGM75 and CGM100 had higher FCA than CGM0 and CGM25. The inclusion of CGM on any level tested resulted in a significant decrease in ADMS, from 77.9 to 66.0%, and ADPC, 80.5 to 52.0%, of the feed. The apparent digestibility of amino acids, except lysine, declined with the addition of CGM, reflecting the ADPC. While those shrimps fed diets based on amaranth showed that the diet with 15% replacement obtained a better growth (p<0.05) after the control diet. Diets with replacement 15% and 25% reported significantly (p<0.05) better DAMS (79.7% and 71.2%) and ADPC (88.4% and 81.1%) than the diet with 35% and 45% substitution. The replacement of quinoa in any of the assessed levels have not demonstrated performance (p<0.05) lower than the control diet. The DAMS and ADPC for quinoa diets were statistically superior (p<0.05) than control diet. These results show that lupine and quinoa have a very good potential as a protein source up to 50% and 45% respectively of the HP protein which is equivalent to a third of the total protein in the diet. The cost-benefit of including these ingredients needs to be evaluated. Lower values of corn gluten and amaranth on the HP could be due to low protein digestibility, imbalance of amino acids and / or the presence of antinutritional factors. / [ES] El presente estudio fue diseñado para evaluar en ensayos independientes el efecto de reemplazar la proteína de la harina de pescado (HP) por cuatro fuentes de origen vegetal, altramuz (Lupinus mutabilis Sweet), gluten de maíz (CGM), amaranto (Amaranthus caudatus L.) y quinua (Chenopodium quinoa) sobre el crecimiento de camarones juveniles Litopenaeus vannamei. Para esto se elaboraron cuatro series de dietas. Las dos primeras conteniendo 35% de proteína y 11% de lípidos fueron preparadas para sustituir el 0, 25, 50, 75 y 100% de la proteína proveniente de la HP por proteína de las harinas de altramuz (LKM) o CGM. Las otras dos series de dietas isoproteicas (30%) e isolipidicas (9,5%) fueron formuladas para reemplazar 0, 15, 25, 35 y 45% de la proteína de la HP por proteína de amaranto y quinua. Solamente los contenidos de almidón de maíz y aceite de pescado variaron para mantener constante los niveles de proteína y lípidos en todas las dietas experimentales. Todas las dietas tuvieron harina de calamar. Dependiendo del ensayo realizado ocho (LKM y CGM) o siete (amaranto y quinua) juveniles de alrededor de 1g fueron sembrados aleatoriamente en los acuarios (44 m-2 o 39 m-2) de 50 l equipados con un sistema de recambio de agua de mar de flujo continuo. Seis acuarios (réplicas) fueron asignadas a cada uno de los tratamientos en un diseño completamente aleatorizado. Los camarones fueron alimentados ad libitum dos veces al día por aproximadamente ocho semanas. Al final del ensayo de crecimiento, los camarones fueron alimentados con las dietas experimentales conteniendo 0,5% de óxido de cromo. La supervivencia en general del estudio fue superior a 74% y no varió significativamente (p>0,05) cuando la HP fue reemplazada parcial o totalmente por cada una de las fuentes evaluadas. Los resultados de este estudio mostraron que LKM puede reemplazar el 50% de la proteína de la HP sin disminuir significativamente (p>0,05) el crecimiento (6,7-7,0 g peso final). La inclusión de LKM en cualquiera de los niveles ensayados resultaron en una significativamente (p<0,05) reducción de la digestibilidad aparente de materia seca (DAMS) y la digestibilidad aparente de proteína cruda (DAPC) del alimento. El gradual incremento del CGM en las dietas produjo un significativo (p<0,05) decrecimiento del peso final (5,9 a 3,2 g) de los camarones y sus tasas de crecimiento (2,7 a 1,7% d-1) comparado a aquellos alimentados con 0 CGM (7,1 g y 3,0 % d-1). El Factor de Conversión Alimenticia (FCA) fue también significativamente (p<0,05) afectado por el nivel de CGM, las dietas CGM50, CGM75 y CGM100 tuvieron un más alto FCA que CGM0 y CGM25. La inclusión de CGM en cualquier nivel ensayado resultó en un significativo decrecimiento en DAMS, de 77,9 a 66,0%, y en DAPC, de 80,5 a 52,0%, del alimento. La digestibilidad aparente de aminoácidos, con la excepción de lisina, declinó con la incorporación de CGM, reflejando la ADPC. En tanto que los camarones alimentados con las dietas a base de amaranto mostraron (p<0,05) que la dieta con 15% de reemplazo obtuvo un mejor crecimiento después de la dieta control. Las dietas con reemplazo de 15% y 25% registraron significativamente (p<0,05) una mejor DAMS (79,70% y 71,21%) y DAPC (88,39% y 81,10%) que las dieta con 35% y 45% de sustitución. El reemplazo de la quinua en cualquiera de los niveles evaluados no demostraron tener un rendimiento (p<0,05) inferior a la dieta control. La DAMS y DAPC para las dietas con quinua fueron estadísticamente superiores (p<0,05) a la dieta control. Estos resultados muestran que el altramuz y quinua tienen un potencial muy bueno como fuente proteína hasta el 50% y 45% respectivamente de la proteína de la HP lo cual es equivalente a un tercio del total de la proteína presente en la dieta. Los valores más bajos del gluten de maíz y amaranto relativo a la HP podrían ser debido a la baja digestibilidad de la proteína, imbalance de aminoácidos y/o a la pres / [CAT] El present estudi va ser dissenyat per a avaluar en assajos independents l'efecte de reemplaçar la proteïna de la farina de peix (HP) per quatre fonts d'origen vegetal, tramús (Lupinus mutabilis Sweet), gluten de dacsa (CGM), amarant (Amaranthus caudatus L.) i quinoa (Chenopodium quinoa) sobre el creixement de gambetes juvenils Litopenaeus vannamei. Per a açò es van elaborar quatre sèries de dietes. Les dos primeres contenint 35% de proteïna i 11% de lípids van ser preparades per a substituir el 0, 25, 50, 75 i 100% de la proteïna provinent de la HP per proteïna de les farines de tramús (LKM) o CGM. Les altres dos sèries de dietes isoproteicas (30%) i isolipidicas (9,5%) van ser formulades per a reemplaçar 0, 15, 25, 35 i 45% de la proteïna de la HP per proteïna d'amarant i quinoa. Només els continguts de midó de dacsa i oli de peix van variar per a mantindre constant els nivells de proteïna i lípids en totes les dietes experimentals. Totes les dietes van tindre farina de calamar per a proveir atractabilidad. Depenent de l'assaig realitzat huit (LKM i CGM) o set (amarant i quinoa) juvenils d'al voltant de 1g van ser sembrats aleatòriament en els aquaris (44 m-2 o 39 m-2) de 50 l equipats amb un sistema de recanvi d'aigua de mar de flux continu. Sis aquaris (rèpliques) van ser assignades a cada un dels tractaments en un disseny completament aleatorizado. Les gambetes van ser alimentats ad libitum dos vegades al dia per aproximadament huit setmanes. Al final de l'assaig de creixement, les gambetes van ser alimentats amb les dietes experimentals contenint 0,5% d'òxid de crom. La supervivència en general de l'estudi va ser superior a 74% i no va variar significativament (p>0,05) quan la HP va ser reemplaçada parcial o totalment per cada una de les fonts avaluades. Els resultats d'este estudi van mostrar que LKM pot reemplaçar el 50% de la proteïna de la HP sense disminuir significativament (p>0,05) el creixement (6,7-7,0 g pes final). La inclusió de LKM en qualsevol dels nivells assajats van resultar en una significativament (p<0.05) reducció de la digestibilitat aparent de matèria seca (DAMS) i la digestibilitat aparent de proteïna crua (DAPC) de l'aliment. El gradual increment del CGM en les dietes va produir un significatiu decreixement del pes final (5,9 a 3,2 g) de les gambetes i les seues taxes de creixement (2,7 a 1,7% d-1) comparat a aquells alimentats amb 0 CGM (7,1 g i 3,0 % d-1). El Factor de Conversió Alimentària (FCA) va ser també significativament (p<0.05) afectat pel nivell de CGM, les dietes CGM50, CGM75 i CGM100 van tindre un més alt FCA que CGM0 i CGM25. La inclusió de CGM en qualsevol nivell assajat va resultar en un significatiu decreixement en DAMS, de 77,9 a 66,0%, i en DAPC, de 80,5 a 52,0%, de l'aliment. La digestibilitat aparent d'aminoàcids, amb l'excepció de lisina, va declinar amb la incorporació de CGM, reflectint l'ADPC. En tant que les gambetes alimentats amb les dietes a base d'amarant van mostrar que la dieta amb 15% de reemplaçament va obtindre un millor creixement després de la dieta control. Les dietes amb reemplaçament de 15% i 25% van registrar significativament una millor DAMS (79,70% i 71,21%) i DAPC (88,39% i 81,10%) que les dieta amb 35% i 45% de substitució. El reemplaçament de la quinoa en qualsevol dels nivells avaluats no van demostrar tindre un rendiment inferior a la dieta control. La DAMS i DAPC per a les dietes amb quinoa van ser estadísticament superiors a la dieta control. Estos resultats mostren que el tramús i quinoa tenen un potencial molt bo com a font proteïna fins al 50% i 45% respectivament de la proteïna de la HP la qual cosa és equivalent a un terç del total de la proteïna present en la dieta. El cost-benefici d'incloure estos ingredients necessita ser avaluat. Els valors més baixos del gluten de dacsa i amarant relatiu a la HP podrien ser degut a la baixa digestibilitat de la proteïna, imbalance d'aminoàcids y/o a / Molina Poveda, C. (2016). Evaluación de varias fuentes de proteína vegetal en dietas para camarón Litopenaeus vannamei [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63666 / TESIS
682

The Skeletal Amino Acid Composition of the Marine Demosponge Aplysina cavernicola

Ueberlein, Susanne, Machill, Susanne, Niemann, Hendrik, Proksch, Peter, Brunner, Eike 07 May 2015 (has links)
It has been discovered during the past few years that demosponges of the order Verongida such as Aplysina cavernicola exhibit chitin-based skeletons. Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We could recently demonstrate that brominated compounds do not exclusively occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and Ianthella basta. Our measurements imply that these yet unknown compounds are strongly, possibly covalently bound to the sponge skeletons. In the present work, we determined the skeletal amino acid composition of the demosponge A. cavernicola especially with respect to the presence of halogenated amino acids. The investigations of the skeletons before and after MeOH extraction confirmed that only a small amount of the brominated skeleton-bound compounds dissolves in MeOH. The main part of the brominated compounds is strongly attached to the skeletons but can be extracted for example by using Ba(OH)2. Various halogenated tyrosine derivatives were identified by GC-MS and LC-MS in these Ba(OH)2 extracts of the skeletons.
683

Determination of the Halogenated Skeleton Constituents of the Marine Demosponge Ianthella basta

Ueberlein, Susanne, Machill, Susanne, Schupp, Peter J., Brunner, Eike 17 July 2017 (has links)
Demosponges of the order Verongida such as Ianthella basta exhibit skeletons containing spongin, a collagenous protein, and chitin. Moreover, Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We recently demonstrated that brominated compounds do not only occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and I. basta. Further investigations revealed the amino acid composition of the skeletons of A. cavernicola including the presence of several halogenated amino acids. In the present work, we investigated the skeletal amino acid composition of the demosponge I. basta, which belongs to the Ianthellidae family, and compared it with that of A. cavernicola from the Aplysinidae family. Seventeen proteinogenic and five non-proteinogenic amino acids were detected in I. basta. Abundantly occurring amino acids like glycine and hydroxyproline show the similarity of I. basta and A. cavernicola and confirm the collagenous nature of their sponging fibers. We also detected nine halogenated tyrosines as an integral part of I. basta skeletons. Since both sponges contain a broad variety of halogenated amino acids, this seems to be characteristic for Verongida sponges. The observed differences of the amino acid composition confirm that spongin exhibits a certain degree of variability even among the members of the order Verongida.
684

Optimization of marker sets and tools for phenotype, ancestry, and identity using genetics and proteomics

Bailey Mae Wills (6989195) 12 October 2021 (has links)
<div><div>In the forensic science community, there is a vast need for tools to help assist investigations when standard DNA profiling methods are uninformative. Methods such as Forensic DNA Phenotyping (FDP) and proteomics aims to help this problem and provide aid in investigations when other methods have been exhausted. FDP is useful by providing physical appearance information, while proteomics allows for the examination of difficult samples, such as hair, to infer human identity and ancestry. To create a “biological eye witness” or develop informative probability of identity match statistics through proteomically inferred genetic profiles, it is necessary to constantly strive to improve these methods. </div><div><br></div><div>Currently, two developmentally validated FDP prediction assays, ‘HIrisPlex’ and ‘HIrisplex-S’, are used on the capillary electrophoresis to develop a phenotypic prediction for eye, hair, and skin color based on 41 variants. Although highly useful, these assays are limited in their ability when used on the CE due to a 25 variant per assay cap. To overcome these limitations and expand the capacities of FDP, we successfully designed and validated a massive parallel sequencing (MPS) assay for use on both the ThermoFisher Scientific Ion Torrent and Illumina MiSeq systems that incorporates all HIrisPlex-S variants into one sensitive assay. With the migration of this assay to an MPS platform, we were able to create a semi-automated pipeline to extract SNP-specific sequencing data that can then be easily uploaded to the freely accessible online phenotypic prediction tool (found at https://hirisplex.erasmusmc.nl) and a mixture deconvolution tool with built-in read count thresholds. Based on sequencing reads counts, this tool can be used to assist in the separation of difficult two-person mixture samples and outline the confidence in each genotype call.<br></div><div><br></div><div>In addition to FDP, proteomic methods, specifically in hair protein analysis, opens doors and possibilities for forensic investigations when standard DNA profiling methods come up short. Here, we analyzed 233 genetically variant peptides (GVPs) within hair-associated proteins and genes for 66 individuals. We assessed the proteomic methods ability to accurately infer and detect genotypes at each of the 233 SNPs and generated statistics for the probability of identity (PID). Of these markers, 32 passed all quality control and population genetics criteria and displayed an average PID of 3.58 x 10-4. A population genetics assessment was also conducted to identify any SNP that could be used to infer ancestry and/or identity. Providing this information is valuable for the future use of this set of markers for human identification in forensic science settings. </div></div><div><br></div>
685

Rheology control mechanisms for amino acid-based surfactant systems

Vu, Trang 04 October 2021 (has links)
No description available.
686

Design, synthesis and biomedical applications of Azabicycloalkanone Amino Acid Peptidomimetics

Atmuri, Nagavenkata 02 1900 (has links)
No description available.
687

Investigation of biological macromolecules using atomic force microscope-based techniques

Bippes, Christian Alexander 18 August 2009 (has links)
The atomic force microscope (AFM) provides a powerful instrument for investigating and manipulating biological samples down to the subnanometer scale. In contrast to other microscopy methods, AFM does not require labeling, staining, nor fixation of samples and allows the specimen to be fully hydrated in buffer solution during the experiments. Moreover, AFM clearly compares in resolution to other techniques. In general, the AFM can be operated in an imaging or a force spectroscopy mode. In the present work, advantage was taken of this versatility to investigate single biomolecules and biomolecular assemblies. A novel approach to investigate the visco-elastic behavior of biomolecules under force was established, using dextran as an example. While a molecule tethered between a solid support and the cantilever tip was stretched at a constant velocity, the thermally driven oscillation of the cantilever was recorded. Analysis of the cantilever Brownian noise provided information about the visco-elastic properties of dextran that corresponded well to parameters obtained by alternative methods. However, the approach presented here was easier to implement and less time-consuming than previously used methods. A computer controlled force-clamp system was set up, circumventing the need for custom built analogue electronics. A commercial PicoForce AFM was extended by two computers which hosted data acquisition hardware. While the first computer recorded data, the second computer drove the AFM bypassing the manufacturer's microscope control software. To do so, a software-based proportional-integral-differential (PID) controller was implemented on the second computer. It allowed the force applied to a molecule to be held constant over time. After tuning of the PID controller, response times obtained using that force-clamp setup were comparable to those of the recently reported analogue systems. The performance of the setup was demonstrated by force-clamp unfolding of a pentameric Ig25 construct and the membrane protein NhaA. In the latter case, short-lived unfolding intermediates that were populated for less than 10 ms, could be revealed. Conventional single-molecule dynamic force spectroscopy was used to unfold the serine:threonine antiporter SteT from Bacillus subtilis, an integral membrane protein. Unfolding force patterns revealed the unfolding barriers stabilizing structural segments of SteT. Ligand binding did not induce new unfolding barriers suggesting that weak interactions with multiple structural segments were involved. In contrast, ligand binding caused changes in the energy landscape of all structural segments, thus turning the protein from a brittle, rigid into a more stable, structurally flexible conformation. Functionally, rigidity in the ligand-free state was thought to facilitate specific ligand binding, while flexibility and increased stability were required for conformational changes associated with substrate translocation. These results support the working model for transmembrane transport proteins that provide alternate access of the binding site to either face of the membrane. Finally, high-resolution imaging was exploited to visualize the extracellular surface of Cx26 gap junction hemichannels (connexons). AFM topographs reveal pH-dependent structural changes of the extracellular connexon surface in presence of HEPES, an aminosulfonate compound. At low pH (&amp;lt; 6.5), connexons showed a narrow and shallow channel entrance, which represented the closed pore. Increasing pH values resulted in a gradual opening of the pore, which was reflected by increasing channel entrance widths and depths. At pH &amp;gt; 7.6 the pore was fully opened and the pore diameter and depth did not increase further. Importantly, coinciding with pore gating a slight rotation of the subunits was observed. In the absence of aminosulfonate compounds, such as HEPES, acidification did not affect pore diameters and depths, retaining the open state. Thus, the intracellular concentration of taurine, a naturally abundant aminosulfonate compound, might be used to tune gap junction sensitivity at low pH.
688

Une nouvelle approche d’isotopomique pour identifier les dysrégulations du métabolisme des protéines et des acides aminés lors du développement du syndrome métabolique / A new isotopomic approach for identifying the dysregulations of protein and amino acid metabolism during the development of the metabolic syndrome

Landry Mantha, Olivier 11 July 2018 (has links)
Si les différentes composantes du syndrome métabolique (SM) sont susceptibles d’affecter le métabolisme protéique et des acides aminés (AA), les données disponibles sont peu nombreuses et souvent contradictoires, du fait de l’hétérogénéité de présentation de ce syndrome et des limites des approches classiques d’investigation du métabolisme azoté. Ce travail de thèse met à profit une nouvelle approche isotopomique, s’appuyant sur la mesure de l’abondance naturelle des isotopes stables de l’azote (δ15N) et du carbone (δ13C) dans les protéines et AA tissulaires pour identifier les altérations du métabolisme protéique survenant lors de l’induction nutritionnelle d’un SM chez le rat. Nos résultats permettent dans un premier temps de valider expérimentalement les prédictions d’un modèle multi-compartimental développé dans le laboratoire et montrant que les δ15N reflètent l’orientation différentielle des AA entre les voies anaboliques (protéosynthèse) et cataboliques (oxydation). Nous avons également montré que sous certaines conditions, les δ13C permettent d’estimer la part des carbones des AA et protéines tissulaires provenant respectivement des protéines, glucides et lipides alimentaires, renseignant ainsi sur la flexibilité métabolique des individus. Les mesures de δ15N et δ13C dans les protéines et AA, seules ou combinées à la mesure des taux de synthèse protéique après administration d’eau deutérée, nous ont ensuite permis de mettre en évidence les modifications du métabolisme protéique et des AA survenant lors de l’exposition périnatale et post-sevrage à un régime gras et sucré, ainsi que celles associées à des différences de sensibilité individuelles à l’induction d’un syndrome métabolique par ce même type de régime. Ces altérations sont tissu-spécifiques et diffèrent selon qu’elles proviennent uniquement de différences de sensibilité individuelle au régime ou qu’elles sont également attribuables à des différences d’équilibre glucido-lipidique dans l’alimentation. L’ensemble de nos résultats montrent que l’apparition d’un SM est associée à des réorientations du métabolisme des AA entre les voies anaboliques et d’oxydation, affectant de façon différente le foie, le muscle, l’intestin et le tissu adipeux, et à une altération de la flexibilité métabolique dans le muscle. Ces travaux ouvrent la voie à des études chez l’Homme, s’appuyant sur les mesures de δ15N et δ13C dans des pools accessibles. / Although the different components of the metabolic syndrome (MS) are likely to affect protein and amino acid (AA) metabolism, the available data are few and often contradictory, due to the heterogeneity of presentation of this syndrome and the limitations of classical approaches to investigate nitrogen metabolism. The present thesis work uses a novel isotopomic approach, based on the measurement of the natural abundance of stable isotopes of nitrogen (δ15N) and carbon (δ13C) in tissue proteins and AA to identify alterations in protein metabolism occurring during the nutritional induction of MS in rats. Our results allow to validate experimentally the predictions of a multi-compartimental model developed in the laboratory and showing that the δ15N reflects the differential orientation of AA between anabolic (proteosynthesis) and catabolic (oxidation) pathways. We have also shown that under certain conditions, the δ13C can allow to estimate the proportion of carbons in AA and tissue proteins issuing from dietary proteins, carbohydrates and lipids respectively, thus providing information on the metabolic flexibility of individuals. The measurements of δ15N and δ13C in proteins and AA, alone or combined with the measurement of protein synthesis rates after administration of deuterated water, then allowed us to highlight the changes in protein and AA metabolism occurring during perinatal and post-weaning exposure to a high-fat high-sugar diet, as well as those associated with individual differences in sensitivity to the induction of a MS by the same kind of diet. These alterations are tissuespecific and differ according to whether they result solely from differences in individual sensitivity to diet or whether they are also attributable to differences in the carbohydrate/lipid balance of the diet. Altogether, our results show that the development of MS is associated with changes in AA metabolic partitioning between the anabolic and oxidative pathways, differently affecting the liver, muscle, intestine and adipose tissue, and with an altered metabolic flexibility in muscle. This work opens the way to human studies, based on the measurements of δ15N and δ 13C in accessible pools.
689

CaMKII regulation of astrocytic glutamate uptake

Chawla, Aarti R. 19 May 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Glutamate clearance by astrocytes is an essential part of physiological excitatory neurotransmission. Failure to adapt or maintain low levels of glutamate in the central nervous system is associated with multiple acute and chronic neurodegenerative diseases. The primary excitatory amino acid transporters (EAATs) in human astrocytes are EAAT1 and EAAT2 (GLAST and GLT-1 respectively in rodents). While the inhibition of a ubiquitously-expressed serine/threonine protein kinase, the calcium/calmodulindependent kinase (CaMKII) results in diminished glutamate uptake in cultured primary rodent astrocytes, the molecular mechanism underlying this regulation is unknown. In order to delineate this mechanism, we use a heterologous expression model to explore CaMKII regulation of EAAT1 and EAAT2. In transiently transfected HEK293T cells, pharmacological inhibition of CaMKII and overexpression of a dominant-negative version of CaMKII (Asp136Asn) reduces [3H]-glutamate uptake by EAAT1, without altering EAAT2 mediated glutamate uptake. Surprisingly, overexpression of a constitutively active autophosphorylation mutant (Thr287Asp) to increase autonomous CaMKII activity and a mutant incapable of autophosphorylation (Thr287Val) had no effect on either EAAT1 or EAAT2 mediated glutamate uptake. Pulldown of FLAGtagged glutamate transporters suggests CaMKII does not interact with EAAT1 or EAAT2. SPOTS peptide arrays and recombinant GST-fusion proteins of the intracellular N- and C-termini of EAAT1 identified two potential phosphorylation sites at residues Thr26 and Thr37 in the N-terminus. Introducing an Ala (a non-phospho mimetic) but not an Asp (phosphomimetic) at Thr37 diminished EAAT1-mediated glutamate uptake, suggesting that the phosphorylation state of this residue is important for constitutive EAAT1 function. In sum, this is the first report of a glutamate transporter being identified as a direct CaMKII substrate. These findings indicate that CaMKII signaling is a critical driver of homeostatic glutamate uptake by EAAT1. Aberrations in basal CaMKII activity disrupt glutamate uptake, which can perpetuate glutamate-mediated excitotoxicity and result in cellular death.
690

Techniky pro porovnávání biologických sekvencí / Techniques for Comparing Biological Sequences

Sladký, Roman January 2008 (has links)
This work presents the building up of basic biological units DNA, RNA and proteins as well as their function. Provided data are kept in biological databases which are connected worldwide to supply preferable communication along with all kinds of available information to be used in the scientific research. The secret of alive is hidden in genes coded in sequences of nucleotides. Genes enable the creation of proteins which are made of sequences of amino-acids. The wide-spread methods of comparing these sequences are FASTA and BLAST algorithms. Their base is used for the PSProt program which is described in this work. PSProt program is the tool for comparing the sequences of proteins. First it is necessary to synthesise the protein from the DNA oligonucleotide because it codes the surveyed protein. The most similar proteins are searched out by heuristic of hitpoints, then their final score that is essential for aligning is modified by semiglobal alignment algorithm.

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