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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.
71

Expressão heteróloga de um transportador mitocondrial de nicotinamida adenina dinucleotídeo (Ndt1) de Aspergillus fumigatus em células HEK293 com deficiência da citrina / Heterologous expression of a mitochondrial nicotinamide adenine dinucleotide transporter (Ndt1) from Aspergillus fumigatus in HEK293 cells with citrin deficiency.

Balico, Laís de Lourdes de Lima 21 November 2018 (has links)
O balanço redox em mitocôndrias de mamíferos é realizado pelo transportador de aspartato-glutamato (AGC), o qual é o principal mecanismo para o movimento de equivalentes redutores na forma de NADH. A citrulinemia do tipo II (CTLN2) é uma doença autossômica recessiva de início tardio, causada por mutações no gene SLC25A13 que codifica a citrina. A citrina é uma isoforma do transportador AGC e catalisa o transporte de glutamato citosólico através da troca com o aspartato mitocondrial, o qual será utilizado no ciclo da ureia. A CTLN2 promove uma deficiência no ciclo da ureia e consequente hiperamonemia. A deficiência da citrina promove um aumento da razão NADH/NAD+ citosólica. O aumento dessa razão inibe a glicólise e a gliconeogênese. O desenvolvimento de modelo in vitro da CTLN2 é importante para estudos do mecanismo da doença e de novas terapias. A expressão heteróloga de proteínas entre diferentes reinos tem sido utilizado como uma forma de corrigir algumas doenças mitocondriais. Estudos bioquímicos e moleculares em nosso laboratório demonstraram a presença de um transportador mitocondrial de nicotinamida adenina dinucleotídeo (Ndt1) em Aspergillus fumigatus. Ndt1 realiza o transporte de NAD+ citosólico para a matriz mitocondrial, sendo dessa forma uma proteína importante para manter o balanço redox em A. fumigatus. Assim, o objetivo deste trabalho foi obter uma linhagem de células de mamífero HEK293 com knockdown para o gene SLC25A13, ou seja, um modelo in vitro de CTLN2 e a expressão heteróloga da proteína Ndt1 como uma forma de recuperação do metabolismo. As células com knockdown para o gene SLC25A13 apresentaram um aumento da razão NADH/NAD+ citosólico, redução da glicólise, redução da concentração da ureia e aumento da concentração de amônia. A expressão de Ndt1 foi capaz de reduzir a razão NADH/NAD+ citosólico e recuperou a atividade glicolítica. Entretanto, a expressão de Ndt1 não foi capaz de aumentar a concentração de ureia e reduzir a concentração de amônia causadas pela CTLN2. Dessa forma, nossos resultados sugerem que a expressão da proteína Ndt1 em células de mamíferos recupera o metabolismo mitocondrial e atividade glicolítica das células com CTLN2, mas não melhora o ciclo da ureia e o aumento da concentração de amônia. / Redox balance in mammalian mitochondria is performed by the aspartate-glutamate carrier (AGC), which is the main mechanism for the movement of reducing equivalents in the form of NADH.Type II citrullinemia (CTLN2) is an adult-onset autosomal recessive disease caused by mutations in SLC25A13 gene, and that coding citrin. Citrin is an isoform of AGC and catalyzes the transport of cytosolic glutamate through exchange with mitochondrial aspartate. It will be used in the urea cycle. CTLN2 causes urea cycle deficiency and hyperammonemia. Citrin deficiency cause an increase in the cytosolic NADH/NAD+ ratio. The increase in this ratio inhibits glycolysis and gluconeogenesis. The development an in vitro CTLN2 model is important for new studies about the disease mechanism and new therapies. Heterologous expression of proteins from different organisms has been used to recover some mitochondrial diseases. Biochemical and molecular studies in our laboratory demonstrated the presence of a mitochondrial nicotinamide adenine dinucleotide transporter (Ndt1) in Aspergillus fumigatus. Ndt1 protein performs cytosolic NAD+ transport to the mitochondria matrix, thus being an important protein to keep the redox balance in A. fumigatus. Thus, the aim of this work was to obtain a line of HEK293 mammalian cells with knockdown for the SLC25A13 gene, an in vitro CTLN2 model and the heterologous expression of the Ndt1 protein as a form of metabolism recovery. Cells with citrin knockdown showed an increase of cytosolic NADH/NAD+ ratio, reduction of glycolysis, reduction of urea concentration, and increase of ammonia concentration. Expression of Ndt1 protein was able to reduce cytosolic NADH/NAD+ ratio and recovered the glycolytic activity. However, Ndt1 protein was not able to increase the urea concentration and reduce of ammonia concentration caused by CTLN2. Thus, our results suggest that expression of Ndt1 protein in mammal cells recovers the mitochondrial metabolism and glycolytic activity in CTLN2 cells but does not improve urea cycle and reduce ammonia concentration.
72

Caracterização molecular e bioquímica de um transportador mitocondrial de nicotinamida adenina dinucleotídeo de Aspergillus fumigatus / Molecular and biochemical characterization of a mitochondrial nicotinamide adenine dinucleotide carrier of Aspergillus fumigatus

Balico, Laís de Lourdes de Lima 03 November 2014 (has links)
O A. fumigatus é um fungo saprofítico e tornou-se um dos principais agente patogênico oportunista em pacientes imunossuprimidos. Estudos prévios em nosso laboratório foi demonstrado que em mitocôndrias de P. brasiliensis e de A. fumigatus, o NAD+ era capaz de induzir a formação de potencial de membrana mitocondrial, o qual podia ser dissipado por FCCP, sugerindo a presença de um transportador de NAD+/NADH, conforme havia sido descrito em S. cerevisiae. Através de ferramentas de bioinformática, foi identificado no Aspergillus Gene Database, uma sequência com 32% de identidade com o gene ndt1p de S. cerevisiae. A sequência de cDNA, contendo 1.194 pb foi obtida usando PCR-Overlaping e clonada em vetor pGEM®-T Easy. Em seguida, a sequência foi subclonada em vetor de expressão pET28-a(+) e expressa em E. coli BL21(DE3). A proteína recombinante foi purificada a partir dos corpos de inclusão e sua identidade confirmada por espectrometria de massas e por Western Blotting usando anticorpo anti-His-tag. A proteína recombinante foi utilizada para produção de anticorpo policlonal anti-Ndt1 em coelho. Para expressão em levedura, o cDNA do gene ndt1 de A. fumigatus foi subclonado em vetor pYES2 e as leveduras S. cerevisiae ?ndt1?ndt2 foram transformadas. Foi realizada a curva de crescimento e indução da expressão da proteína recombinante Ndt1, a presença da proteína foi detectada utilizando anticorpo policlonal anti-Ndt1 após 16 horas de expressão. Nesse período foi verificado que as leveduras estavam em fase de crescimento exponencial. A cepa duplo mutante apresenta uma taxa de crescimento menor quando comparada com a cepa expressando a proteína recombinante quando crescidas em meio fermentável. As mitocôndrias isoladas de ambas as cepas foram submetidas à medida do potencial de membrana onde apresentavam acoplamento entre a oxidação de substratos e a fosforilação oxidativa. Além disso, ficou evidenciado que na cepa expressando a proteína recombinante, NAD+ induziu a formação de um potencial de membrana maior que na cepa controle. O transporte de NAD+ foi realizado e demonstrou que a cepa expressando a proteína Ndt1 tinha um aumento na fluorescência de NADH, mostrando que NAD+ foi capaz de entrar na matriz mitocondrial e posteriormente ser reduzido a NADH por enzimas da matriz mitocondrial. A determinação da produção de espécies reativas de oxigênio foi realizada utilizando as sondas fluorescentes CM-H2DCFDA e MitoSox Red em esferoplastos da levedura S. cerevisiae. Ambos experimentos não houve diferença significativa entre a cepa expressando a proteína Ndt1 e a cepa controle. As proteínas carboniladas foram determinadas utilizando anticorpo anti-DNP, após a reação com dinitrofenilhidrazona e não há diferença significativa entre as cepas. Finalmente, para confirmação da localização celular da proteína Ndt1, os esferoplastos de S. cerevisiae foram submetidos à microscopia confocal, onde ficou evidenciado a co-localização da proteína Ndt1 com as mitocôndrias na cepa de S. cerevisiae transformada com a construção pYES/ndt1, o mesmo perfil não foi observado na cepa ?ndt1?ndt2. / The A. fumigatus is a saprophytic fungus and is a major opportunistic pathogen in immunosuppressed patients. Previous studies in our lab has showed that mitochondrias of the P. brasiliensis and A. fumigatus, NAD+ is able to induce the formation of mitochondrial membrane potential, which could be dissipated by FCCP, suggesting the presence of a NAD+/NADH carrier as described in S. cerevisiae. Using bioinformatics tools, it was identified in Aspergillus Gene database a sequence containing 32% of identity with the gene ndt1p of S. cerevisiae. A fragment of cDNA was obtained from the ndt1p mRNA sequence, containing 1194 bp by using PCR-overlaping and cloned in pGEM®-T Easy vector. Then, the sequence was subcloned in pET28-a(+) vector and expressed in E. coli BL21 (DE3). The recombinant protein was purified from inclusion bodies and the identity confirmed by mass spectrometry and by Western Blotting using anti-His-tag antibody. The recombinant protein was used to produce polyclonal antibody anti-Ndt1 in rabbit. For expression in yeast, the ndt1 cDNA of A. fumigatus was subcloned into pYES2 vector and the yeast S. cerevisiae ?ndt1?ndt2 were transformed. Growth curve and induction of the recombinant protein expression Ndt1 was performed and the protein was detected using a polyclonal anti-Ndt1 antibody after 16 hours of expression. During this period it was found that the yeast were in exponential growth phase. The double mutant strain shows a slower growth rate compared to the strain expressing the recombinant protein growth rate when grown in fermentable medium. The isolated mitochondria from both strains were subjected to measurement of the membrane potential which showed coupling between substrate oxidation and oxidative phosphorylation. Furthermore, these measurements evidenced that the strain expressing the recombinant protein NAD+ induced the formation of a membrane potential larger than the control strain. The transport NAD+ was evaluated and showed that the strain expressing the protein Ndt1 has an increase in NADH fluorescence, indicating that NAD+ was able to enter into the mitochondrial matrix and then reduced to NADH by enzymes from the matrix. The determination of the production of reactive oxygen species was performed using the fluorescent probe CM-H2DCFDA and MitoSox Red in spheroplasts of the yeast S. cerevisiae. Both experiments showed no significant difference between the strain expressing Ndt1 protein and strain control. The carbonylated proteins levels were checked using anti-DNP, after the reaction with dinitrophenylhydrazone and there is no significant difference between the strains. Finally, to confirm the cellular localization of the protein Ndt1, spheroplasts of S. cerevisiae were subjected to confocal microscopy, which evidenced the co-location of Ndt1 protein with mitochondria in S. cerevisiae strain transformed with the construction pYES/ndt1. This same profile was not observed in strain ?ndt1?ndt2.
73

Methods For Understanding Bacterial Metabolic Activity In Activated Sludge

Wos, Melissa Louise, n/a January 2005 (has links)
Biological wastewater treatment relies on the diverse and complex metabolic activities of bacteria to remove pollutants. Its success depends on the metabolic efficiency of the bacteria. Activated sludge models use parameters that attempt to depict bacterial growth and metabolic processes. However, current methods do not separate metabolic activity from growth and maintenance. As a result, activated sludge processes are misinterpreted or over-simplified. Alternative methods for gauging bacterial activity have been proposed and include the measurements of cellular derived compounds that relate specifically to energy cycling and include Nicotinamide Adenine Dinucleotide [NADH]. To date, NADH has been largely measured within activated sludge using commercial online fluorimeters with in situ probes. However, this current method provides a measure of the 'bulk' (raw) fluorescence within the system, resulting in difficulties when interpreting fluorescence data and poor sensitivity for detecting changes in intracellular [NADH]. This study has developed a more reliable method for estimating intracellular [NADH] and thus metabolic activity within activated sludge systems. Separating extracellular from intracellular [NADH] in samples was crucial because NADH was released and accumulates in the extracellular environment at a concentration of 200 ~M immediately following bacterial death or lysis. This concentration did not decline overtime. This not only caused high background fluorescence but also reduced the sensitivity of detection for changes in intracellular [NADH]. In particular, considerably higher [NADH] values to those from the extracellular suspensions were obtained following extraction of the intracellular material, suggesting that the cell membranes were not being penetrated by the excitable light source. Of the extraction procedures examined, filtration followed by extraction of the intracellular material with a hot Tris buffer was the most efficient and was recommended for accurate estimates of intracellular [NADH] in situ. In addition, standards were used to quantify NADH (moles per cell and/or unit volume) from unknown samples. The limits of detection were found to be 1.058 - 353 uM, whereas concentrations above 353 jAM self-quenched. Sample concentrations were always within these limits of detection. Hence, the sensitivity, reliability and experimental application of the original method was improved upon and able to be used for the direct measurement of microbial metabolic activity, something that has not been demonstrated before now. This study found that bacteria have between 106~ I 08 NADH molecules per cell depending on their metabolic state. A highly metabolically active bacterial cell had between 1O6~ tO7 NADH molecules, while a less active bacterial cell had between to7 -to8 NADH molecules. These measurements of metabolic activity were simultaneously monitored alongside other measures of bacterial growth, such as the incorporation of radiolabelled thymidine into DNA as a direct measure of DNA replication (new cell synthesis), the incorporation of radiolabelled leucine into protein as a direct measure of protein synthesis, oxygen uptake rates (OUR) as a direct measure of respiration, ATP as a measure of potential energy and dissolved organic carbon (DOC) as a measure of substrate assimilation. As OUR deceased, bacterial growth (using both the thymidine and leucine assays), specific [NADH] and specific [ATP] increased. High OUR and substrate oxidation rates simultaneous with low specific [NADH] indicated high rates of electron transport and thus efficient metabolic activity. Also, low OUR and substrate oxidation rates simultaneous with high specific [NADHI indicated inefficient rates of electron transport, therefore inhibiting oxidative phosphorylation (ATP production). A lack of oxygen as the terminal electron acceptor did not efficiently reoxidise NADH to NAD and resulted in an accumulation of NADH within the cell. Thus, a measure of low specific [NADHI was linked to the efficient rate of reoxidation of NADH to NAD* and reflects high metabolic efficiency. DNA and protein syntheses were coupled following substrate enrichment (glucose or acetate), indicating that bacteria were in balanced growth. However, DNA and protein syntheses became uncoupled once substrate was depleted, indicating unbalanced growth. An average Leu:TdR ratio of 7.4 was determined for activated sludge and was comparable to values published from marine systems. This ratio increased during log growth phase and decreased during stationary growth phases. Specific growth rates determined using the [3HITdR and [3H]Leu assay yielded values ranging from 2 - 10.5 d' and from 2.5 - 6 d1, respectively and were comparable to published values. Changes in OUR, NADH, ATE', DNA replication and protein synthesis were statistically ordinated using multidimensional scaling, and changes (in magnitude and direction) in bacterial metabolic activity were observed. Such methods enable the tracing of where bacteria divert their energies, such as to growth or maintenance and thus provide a greater understanding of bacterial behaviour in activated sludge. While studying anoxic and anaerobic conditions were beyond the scope of this work, the use of such methods to monitor bacterial metabolic activity under such conditions is warranted.
74

ARCON in experimental and clinical radiotherapy

Rojas Callejas, Ana Maria January 2004 (has links)
xHypoxia and repopulation of tumour clonogens are two important determinants of treatment outcome in radiotherapy. In general clinical evidence indicates that loco-regional control may be reduced with long overall treatment times and for tumours with low pre-treatment levels of oxygen. Experimental studies with normobaric carbogen and oxygen showed a two-fold enhancement of the efficacy of radiation in a mouse tumour model when combining oxygen with treatment acceleration. It was then demonstrated that substituting carbogen for oxygen and adding high-dose nicotinamide (NAM) further increased the effect. These findings became the basis for a multi-factorial approach designed to overcome the radioprotective effect of tumour repopulation and that of perfusion–limited and diffusion–limited hypoxia. The strategy, named ARCON, combines Accelerated Radiotherapy with CarbOgen and Nicotinamide. Experimental evaluation of ARCON The therapeutic potential of carbogen combined with NAM (CON) focusing on treatment schedules that use clinically relevant radiation and drug dose levels was evaluated in tumour and normal tissue animal models. Some of the conditions under which ARCON gives the largest degree of tumour radiosensitization and therapeutic benefit were identified. Specifically, NAM-dose level, pharmacokinetics and scheduling, and the effect of NAM on repair processes in vivo were also investigated. The results showed that in conventional and accelerated radiotherapy, carbogen and CON are effective and relatively non-toxic tumour sensitizers. They also demonstrated that tumour sensitization with CON was independent of time of NAM administration but that it was drug dose dependent. Some degree of normal tissue sensitization was observed but even relative to mouse skin a significant therapeutic gain was achieved. The mechanism of action for NAM sensitization originally proposed was that of repair inhibition. In the in vivo mouse models tested, namely skin and kidney, NAM did not alter the rate nor the magnitude of repair of radiation induced damage. Clinical evaluation of ARCON In the early 90s, various centres, particularly in the UK, Sweden, Holland and Switzerland, undertook clinical trials of ARCON. The protocols were designed based on detailed considerations of the rodent and human radiation and pharmacokinetic studies. This document also discusses the findings of a phase II non-randomized trial in advanced bladder cancer of accelerated radiotherapy combined with carbogen alone and ARCON. The aim of the study was to establish the feasibility of administering carbogen and NAM to patients and to determine the extent of early and late normal tissue damage. Historical comparisons suggested no overt increase in normal tissue radiosensitivity and the data indicate that ARCON could achieve a therapeutic gain in advanced bladder cancer.
75

Caracterização molecular e bioquímica de um transportador mitocondrial de nicotinamida adenina dinucleotídeo de Aspergillus fumigatus / Molecular and biochemical characterization of a mitochondrial nicotinamide adenine dinucleotide carrier of Aspergillus fumigatus

Laís de Lourdes de Lima Balico 03 November 2014 (has links)
O A. fumigatus é um fungo saprofítico e tornou-se um dos principais agente patogênico oportunista em pacientes imunossuprimidos. Estudos prévios em nosso laboratório foi demonstrado que em mitocôndrias de P. brasiliensis e de A. fumigatus, o NAD+ era capaz de induzir a formação de potencial de membrana mitocondrial, o qual podia ser dissipado por FCCP, sugerindo a presença de um transportador de NAD+/NADH, conforme havia sido descrito em S. cerevisiae. Através de ferramentas de bioinformática, foi identificado no Aspergillus Gene Database, uma sequência com 32% de identidade com o gene ndt1p de S. cerevisiae. A sequência de cDNA, contendo 1.194 pb foi obtida usando PCR-Overlaping e clonada em vetor pGEM®-T Easy. Em seguida, a sequência foi subclonada em vetor de expressão pET28-a(+) e expressa em E. coli BL21(DE3). A proteína recombinante foi purificada a partir dos corpos de inclusão e sua identidade confirmada por espectrometria de massas e por Western Blotting usando anticorpo anti-His-tag. A proteína recombinante foi utilizada para produção de anticorpo policlonal anti-Ndt1 em coelho. Para expressão em levedura, o cDNA do gene ndt1 de A. fumigatus foi subclonado em vetor pYES2 e as leveduras S. cerevisiae ?ndt1?ndt2 foram transformadas. Foi realizada a curva de crescimento e indução da expressão da proteína recombinante Ndt1, a presença da proteína foi detectada utilizando anticorpo policlonal anti-Ndt1 após 16 horas de expressão. Nesse período foi verificado que as leveduras estavam em fase de crescimento exponencial. A cepa duplo mutante apresenta uma taxa de crescimento menor quando comparada com a cepa expressando a proteína recombinante quando crescidas em meio fermentável. As mitocôndrias isoladas de ambas as cepas foram submetidas à medida do potencial de membrana onde apresentavam acoplamento entre a oxidação de substratos e a fosforilação oxidativa. Além disso, ficou evidenciado que na cepa expressando a proteína recombinante, NAD+ induziu a formação de um potencial de membrana maior que na cepa controle. O transporte de NAD+ foi realizado e demonstrou que a cepa expressando a proteína Ndt1 tinha um aumento na fluorescência de NADH, mostrando que NAD+ foi capaz de entrar na matriz mitocondrial e posteriormente ser reduzido a NADH por enzimas da matriz mitocondrial. A determinação da produção de espécies reativas de oxigênio foi realizada utilizando as sondas fluorescentes CM-H2DCFDA e MitoSox Red em esferoplastos da levedura S. cerevisiae. Ambos experimentos não houve diferença significativa entre a cepa expressando a proteína Ndt1 e a cepa controle. As proteínas carboniladas foram determinadas utilizando anticorpo anti-DNP, após a reação com dinitrofenilhidrazona e não há diferença significativa entre as cepas. Finalmente, para confirmação da localização celular da proteína Ndt1, os esferoplastos de S. cerevisiae foram submetidos à microscopia confocal, onde ficou evidenciado a co-localização da proteína Ndt1 com as mitocôndrias na cepa de S. cerevisiae transformada com a construção pYES/ndt1, o mesmo perfil não foi observado na cepa ?ndt1?ndt2. / The A. fumigatus is a saprophytic fungus and is a major opportunistic pathogen in immunosuppressed patients. Previous studies in our lab has showed that mitochondrias of the P. brasiliensis and A. fumigatus, NAD+ is able to induce the formation of mitochondrial membrane potential, which could be dissipated by FCCP, suggesting the presence of a NAD+/NADH carrier as described in S. cerevisiae. Using bioinformatics tools, it was identified in Aspergillus Gene database a sequence containing 32% of identity with the gene ndt1p of S. cerevisiae. A fragment of cDNA was obtained from the ndt1p mRNA sequence, containing 1194 bp by using PCR-overlaping and cloned in pGEM®-T Easy vector. Then, the sequence was subcloned in pET28-a(+) vector and expressed in E. coli BL21 (DE3). The recombinant protein was purified from inclusion bodies and the identity confirmed by mass spectrometry and by Western Blotting using anti-His-tag antibody. The recombinant protein was used to produce polyclonal antibody anti-Ndt1 in rabbit. For expression in yeast, the ndt1 cDNA of A. fumigatus was subcloned into pYES2 vector and the yeast S. cerevisiae ?ndt1?ndt2 were transformed. Growth curve and induction of the recombinant protein expression Ndt1 was performed and the protein was detected using a polyclonal anti-Ndt1 antibody after 16 hours of expression. During this period it was found that the yeast were in exponential growth phase. The double mutant strain shows a slower growth rate compared to the strain expressing the recombinant protein growth rate when grown in fermentable medium. The isolated mitochondria from both strains were subjected to measurement of the membrane potential which showed coupling between substrate oxidation and oxidative phosphorylation. Furthermore, these measurements evidenced that the strain expressing the recombinant protein NAD+ induced the formation of a membrane potential larger than the control strain. The transport NAD+ was evaluated and showed that the strain expressing the protein Ndt1 has an increase in NADH fluorescence, indicating that NAD+ was able to enter into the mitochondrial matrix and then reduced to NADH by enzymes from the matrix. The determination of the production of reactive oxygen species was performed using the fluorescent probe CM-H2DCFDA and MitoSox Red in spheroplasts of the yeast S. cerevisiae. Both experiments showed no significant difference between the strain expressing Ndt1 protein and strain control. The carbonylated proteins levels were checked using anti-DNP, after the reaction with dinitrophenylhydrazone and there is no significant difference between the strains. Finally, to confirm the cellular localization of the protein Ndt1, spheroplasts of S. cerevisiae were subjected to confocal microscopy, which evidenced the co-location of Ndt1 protein with mitochondria in S. cerevisiae strain transformed with the construction pYES/ndt1. This same profile was not observed in strain ?ndt1?ndt2.
76

Modification of Cardiac Membrane Gsα by an Endogenous Arginine-Specific Mono-Adp-Ribosyltransferase

Coyle, Donna L. (Donna Lynn) 12 1900 (has links)
The mechanism by which nicotinamide adenine dinucleotide (NAD) stimulates the activity of adenylate cyclase (AC) in canine plasma membrane has been studied. Using [3 2P]-NAD, the activation by NAD was correlated with the radiolabeling of the stimulatory guanosine triphosphate (GTP) binding protein Gsa. Further characterization demonstrated that the modification occurred only in the presence of G-protein activators and that arginine residue(s) were modified by ADP-ribose by the action of a mono-ADP-ribosyltransferase. Inhibitors of the transferase blocked both the modification of Gsa and the activation of AC. Collectively, these studies suggest that ADP-ribosylation of Gsa by an endogenous mono-ADP-ribosyltransferase may regulate cardiac AC.
77

Cytoplasmic and Mitochondrial NADPH-Coupled Redox Systems in the Regulation of Aging

Bradshaw, Patrick C. 01 March 2019 (has links)
The reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) protects against redox stress by providing reducing equivalents to antioxidants such as glutathione and thioredoxin. NADPH levels decline with aging in several tissues, but whether this is a major driving force for the aging process has not been well established. Global or neural overexpression of several cytoplasmic enzymes that synthesize NADPH have been shown to extend lifespan in model organisms such as Drosophila suggesting a positive relationship between cytoplasmic NADPH levels and longevity. Mitochondrial NADPH plays an important role in the protection against redox stress and cell death and mitochondrial NADPH-utilizing thioredoxin reductase 2 levels correlate with species longevity in cells from rodents and primates. Mitochondrial NADPH shuttles allow for some NADPH flux between the cytoplasm and mitochondria. Since a decline of nicotinamide adenine dinucleotide (NAD + ) is linked with aging and because NADP + is exclusively synthesized from NAD + by cytoplasmic and mitochondrial NAD + kinases, a decline in the cytoplasmic or mitochondrial NADPH pool may also contribute to the aging process. Therefore pro-longevity therapies should aim to maintain the levels of both NAD + and NADPH in aging tissues.
78

Effects of Creatine and Nicotinamide on experimentally induced senescence in dermal fibroblasts.

Mahajan, Avinash Satyanarayan 02 September 2020 (has links)
No description available.
79

Stress-Induced Senescence in Human Dermal Fibroblasts: Effects of Creatine and Nicotinamide Post Stress Treatment

Arikatla, Venkata Sravya 27 August 2021 (has links)
No description available.
80

Investigating co-crystallisation of primary amides and carboxylic acids : comparative analysis of Benzamide, Isonicotinamide and Nicotinamide co-crystal growth with carboxylic acid

Javed, Hafsa Shamim January 2010 (has links)
Crystal Engineering is the design of crystalline material using non-covalent synthesis. Co-crystals are multi-component crystals which are constructed from complementary intermolecular interactions, they are also known as supramolecular complexes. Design of such materials utilises the synthon approach, this involves the understanding of common intermolecular interactions which occur in the crystal packing and is used to design new solids with desired physical properties and chemical properties. Primary amides form supramolecular heterosynthons, these synthons represent an opportunity for a design of multi-component crystals in which one molecule contains a primary amide and a second molecule which is complimentary to the primary amide, usually carboxylic acids. The progress with regards to the screening process for the determination of co-crystals is evident in the literature, In particular, high throughput solution growth methods and solvent drop grinding. The comparison of Isonicotinamide and Benzamide as a co-crystal component has been presented. This study was motivated by the observation that the CSD contains 24 Isonicotinamide and 1 Benzamide co-crystal. The interaction with carboxylic acids is the focus of the work, in particular those which form Isonicotinamide co-crystal are being screened with Benzamide. Our work utilises a ReactArray Microvate to carry out the low throughput solution growth on a matrix of carboxylic acid with Benzamide, this study has been coupled with the Kofler hot stage microscope method which visually aids to screen and view co-crystal phase formation. Crystallisation screens have resulted in the identification of known co-crystal phases of Isonicotinamide and Benzamide, additionally new co-crystal phases have also been identified with Fumaric, 3-hydroxybenzoic acid, Mandelic Acid, 4-Nitrobenzoic Acid and Tartaric Acid. Single crystal structures of the Fumaric and 4-Nitrobenzoic acid have been obtained. In order to develop an understanding of co-crystal formation in Isonicotinamide and Benzamide with our supramolecular library, packing landscape analysis is being undertaken using both the CSD and crystal structures we have obtained. This is undertaken as collaboration with Dr Andy Parkin and Professor Gilmore (University of Glasgow), we have identified that the dSNAP analysis is a way forward for the analysis of how co-crystals pack. The analysis highlighted the subtleties that were present in the packing motifs of the Isonicotinamide co-crystals. In particular the cis and trans orientation of the amide and acid carbonyl to each other and the planar and off planar layer assemblies. All of which are required to maximise the hydrogen bond usage of the components comprising the co-crystals. Further investigations have led to the collaborative project with Syngenta Ltd in the design of a co-crystal screen using a high through-put robot, Crissy® -Automation Platform by Zinsser Analytical, using an extended screen of 16 acid coformers with Isonicotinamide, Benzamide and Nicotinamide the sample have been characterised using a reflectance diffraction method, GADDS. Further analysis of this data involves the use of polySNAP, which has led to further collaboration with Professor Gilmore's group.

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