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Níveis de isoleucina e valina digestíveis em dietas contendo farinha de carne e ossos para poedeiras comerciais

Gravena, Rodrigo Antonio
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: iv, 51 p.
POR
Relevância na Pesquisa
164.0798%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Zootecnia - FCAV; Avaliou-se o desempenho, a qualidade de ovos, o metabolismo de nitrogênio e os níveis de aminoácidos plasmáticos de poedeiras comerciais alimentadas com rações formuladas à base de milho e farelo de soja com a inclusão de farinha de carne e ossos e diferentes relações de isoleucina:lisina e valina:lisina digestíveis. Foram utilizadas 640 poedeiras da linhagem Isa Brown com 40 semanas de idade distribuídas em delineamento inteiramente casualizado em esquema fatorial 3x3+1, sendo 0,55; 0,62 e 0,70% de isoleucina e 0,60; 0,67 e 0,75% de valina digestíveis (dietas basais com 15,09% de proteína bruta e 0,75% de lisina digestível) e, o tratamento controle com 17,55% de proteína bruta, totalizando 10 tratamentos com oito repetições e oito aves por parcela. O peso dos ovos das aves alimentadas com dieta controle foi maior em relação ao peso dos ovos das aves que receberam os outros tratamentos, a unidade Haugh dos ovos das aves que receberam 0,70% de isoleucina na dieta foi menor do que os ovos provenientes de aves alimentadas com dietas contendo 0,62% de isoleucina. As dietas contendo 0,55% de isoleucina, independentemente do nível de valina...

Níveis de isoleucina e de valina digestíveis para poedeiras comerciais

Marques, Rafael Henrique
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: viii, 67 p.
POR
Relevância na Pesquisa
169.09473%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Zootecnia - FCAV; Dois experimentos foram realizados com o objetivo de se avaliar o desempenho, a qualidade dos ovos, o balanço de nitrogênio, a concentração de aminoácidos plasmáticos e o custo da ração de poedeiras formuladas à base de milho e farelo de soja, com diferentes níveis de isoleucina (0,55%; 0,62% e 0,70%) e de valina digestíveis (0,60%; 0,67% e 0,75%). Foram utilizadas 640 poedeiras Isa Brown, com 40 semanas de idade, distribuídas em um delineamento inteiramente casualizado, em esquema fatorial 3 x 3 + 1 (3 níveis de isoleucina digestíveis, três níveis de valina digestíveis e + um tratamento controle), totalizando 10 tratamentos com oito repetições de oito aves cada. A porcentagem de postura e o peso dos ovos sofreram influência negativa e positiva, respectivamente, do tratamento com 17% de proteína bruta. Independente do nível de valina, o tratamento com 0,70% de isoleucina apresentou menor consumo de ração e as melhores conversões alimentares por kg e dúzia de ovos. A unidade Haugh dos ovos no tratamento com 0,67% de valina na dieta foi maior do que nos ovos do tratamento com 0,60%. O tratamento com 0,70% de isoleucina proporcionou menor porcentagem de gema e maior porcentagem de albúmen. As aves alimentadas com o tratamento controle ingeriram e excretaram maior quantidade de nitrogênio. De acordo com os níveis plasmáticos obtidos...

Critérios de avaliação das exigências em treonina, triptofano, valina e isoleucina para frangos de corte de 22 a 42 dias de idade

Duarte, Karina Ferreira
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: xvii, 118 f.
POR
Relevância na Pesquisa
164.0798%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Zootecnia - FCAV; Quatro experimentos foram conduzidos no Setor de Avicultura da Faculdade de Ciências Agrárias e Veterinárias – Campus de Jaboticabal- SP, com o objetivo de estabelecer diferentes critérios de avaliação das exigências dos aminoácidos digestíveis treonina, triptofano, valina e isoleucina para frangos de corte de 22 a 42 dias de idade. Em cada experimento foram utilizados 1.920 frangos de corte machos com 22 dias de idade da linhagem “Cobb”, distribuídos em um delineamento inteiramente ao acaso, com seis tratamentos e oito repetições de 40 aves cada. Os tratamentos consistiram no fornecimento de dietas formuladas com base em aminoácidos digestíveis contendo seis diferentes níveis do aminoácido em estudo. Foram avaliados os dados de desempenho (ganho de peso, consumo de ração, conversão alimentar e viabilidade criatória) e as características de carcaça (rendimento de carcaça, de peito, de coxas+sobrecoxas, de dorso e de asas). Para a determinação das exigências do aminoácido estudado, foram utilizados três modelos de regressão: o modelo quadrático, o modelo exponencial e o de retas segmentadas ou broken line (“linha quebrada”)...

Níveis de valina, isoleucina e arginina em dietas com baixo nível protéico para codornas japonesas em postura

Santos, Graciene Conceição dos
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: vi, 103 f. : grafs., tabs.
POR
Relevância na Pesquisa
171.64332%
Pós-graduação em Zootecnia - FMVZ; Com o objetivo de avaliar níveis de valina em rações de baixo nível protéico para codornas japonesas na fase de postura, foram utilizadas 648 codornas, com 154 dias de idade, taxa de postura inicial média de 86,26% distribuídas em delineamento experimental em blocos ao acaso, constituídos por seis tratamentos e seis repetições de 18 aves por unidade experimental. Os tratamentos consistiram de ração basal com 16% de PB correspondente ao nível de valina de 0,686% e suplementada com valina (0,197; 0,344; 0,491; 0,638% na ração), em substituição ao ácido glutâmico, em equivalente protéico, correspondendo aos níveis de valina de 0,833; 0,980; 1,127; 1,274%. As dietas experimentais foram comparadas a uma dieta controle contendo 20% PB, totalizando seis tratamentos e os níveis dos demais nutrientes também de acordo com Silva (2009). Os parâmetros estudados foram: consumo de ração, de proteína bruta e de valina, porcentagem de postura, porcentagem de ovos íntegros, peso médio dos ovos, massa de ovos, conversão alimentar por dúzia e por quilograma de ovos produzidos, viabilidade, gravidade específica, porcentagens de gema, albúmen e casca, espessura da casca, resistência da casca à quebra...

Effect of cutting on solute uptake by plasma membrane vesicles from sugar beet (Beta vulgaris L.) leaves.

Sakr, S; Lemoine, R; Gaillard, C; Delrot, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1993 EN
Relevância na Pesquisa
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The uptake of sucrose, 3-O-methylglucose (3-O-MeG), and valine were studied in discs and in purified plasma membrane vesicles (PMV) prepared from sugar beet (Beta vulgaris L.) exporting leaves. The uptake capacities of freshly excised leaf discs were compared with the uptake in discs that had been floated for 12 h on a simple medium (aging) and with discs excised from leaves that had been cut from the plant 12 h before the experiments (cutting). After cutting, sucrose uptake amounted to twice the uptake measured in fresh discs, whereas the uptake of 3-O-MeG and valine remained unaffected. In aged leaf discs, there was a general stimulation of uptake, which represented 400, 300, and 400% of the uptake measured in fresh discs for sucrose, 3-O-MeG, and valine, respectively. Sucrose uptake in fresh discs was sensitive to N-ethylmaleimide (NEM), to p-chloromercuribenzenesulfonic acid (PCMBS), and to mersalyl acid (MA). Although cutting induced the appearance of a sucrose uptake system that is poorly sensitive to NEM but sensitive to PCMBS and MA, aging induced the development of an uptake system that is sensitive to NEM but poorly sensitive to PCMBS and MA. Autoradiographs of discs fed with [14C]sucrose show that cutting resulted in an increase of vein labeling with little effect in the mesophyll...

Regulation of expression of the ilvB operon in Salmonella typhimurium.

Weinberg, R A; Burns, R O
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1984 EN
Relevância na Pesquisa
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The ilvB gene of Salmonella typhimurium encodes the valine-sensitive form of acetohydroxy acid synthase, acetohydroxy acid synthase I, which catalyzes the first step in the parallel biosynthesis of isoleucine and valine. Although nearly all of the other genes involved in this pathway are clustered at minute 83, ilvB was found to lie at minute 80.5. Expression of ilvB was shown to be nearly completely repressed by the end products leucine and valine. Studies in which we used strains with mutations in cya (adenylate cyclase) and crp (cAMP receptor protein) demonstrated that synthesis of acetohydroxy acid synthase I is enhanced by the cAMP-cAMP receptor protein complex. Although no stimulation was achieved by growth on poor carbon sources, introduction of crp on a multicopy plasmid led to markedly increased expression. Strains of S. typhimurium lacking valine-resistant acetohydroxy acid synthase II (ilvG) are like Escherichia coli K-12 in that they are not able to grow in the presence of L-valine owing to a conditional isoleucine auxotrophy. The valine toxicity of these ilvG mutants of S. typhimurium was overcome by increasing the level of acetohydroxy acid synthase I. Enzyme activity could be elevated either by maximally derepressing expression with severe leucine limitation...

Purification of a branched-chain keto acid dehydrogenase from Pseudomonas putida.

Sokatch, J R; McCully, V; Roberts, C M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1981 EN
Relevância na Pesquisa
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We purified branched-chain keto acid dehydrogenase to a specific activity of 10 mumol/min per mg of protein from Pseudomonas putida grown on valine. The purified enzyme was active with 2-ketoisovalerate, 2-ketoisocaproate, and 2-keto-3-methylvalerate in a ratio of 1.0:0.8:0.7 but showed no activity with either pyruvate or 2-ketoglutarate. There were four polypeptides in the purified enzyme (molecular weights, 49,000, 46,000, 39,000, and 37,000). The purified enzyme was deficient in the specific lipoamide dehydrogenase produced during growth on valine (molecular weight, 49,000). Branched-chain keto acid dehydrogenase required L-valine, oxidized nicotinamide adenine dinucleotide, coenzyme A, thiamine pyrophosphate, and magnesium chloride. A partially purified preparation catalyzed the oxidation of 2-keto-[1-14C]isovalerate to [14C]carbon dioxide, isobutyryl-coenzyme A, and reduced nicotinamide adenine dinucleotide in equimolar amounts. Both the Km and the Vmax for 2-ketoisovalerate were affected by the addition of L-valine to the assay mixture. However, only the Vmax values for oxidized nicotinamide adenine dinucleotide and coenzyme A were affected when L-valine was present. This suggested that valine acted by affecting the binding of branched-chain keto acids to subunit E1 of the complex.

Repression and inhibition of transport systems for branched-chain amino acids in Salmonella typhimurium.

Kiritani, K; Ohnishi, K
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1977 EN
Relevância na Pesquisa
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Kinetics of the transport systems common for entry of L-isoleucine, L-leucine, and L-valine in Salmonella typhimurium LT2 have been analyzed as a function of substrateconcentration in the range of 0.5 to 45 muM. The systems of transport mutants, KA203 (ilvT3) and KA204 (ilvT4), are composed of two components; apparent Km values for uptake of isoleucine, leucine, and valine by the low Km component are 2 muM, 2 to 3 muM, and 1 muM, respectively, and by the high Km component 30 muM, 20 to 40 muM, and 0.1 mM, respectively. The transport system(s) of the wild type has not been separated into components but rather displays single Km values of 9 muM for isoleucine, 10 muM for leucine, and 30 muM for valine. The transport activity of the wild type was repressed by L-leucine, alpha ketoisocaproate, glycyl-L-isoleucine, glycyl-L-leucine, and glycyl-L-methionine. That for the transport mutants was repressed by L-alanine, L-isoleucine, L-methionine, L-valine, alpha-ketoisovalerate, alpha-keto-beta-methylvalerate, glycyl-L-alanine, glycyl-L-threonine, and glycyl-L-valine, in addition to the compounds described above. Repression of the mutant transport systems resulted in disappearance of the low Km component for valine uptake, together with a decrease in Vmax of the high Km component; the kinetic analysis with isoleucine and leucine as substrates was not possible because of poor uptake. The maximum reduction of the transport activity for isoleucine was obtained after growing cells for two to three generations in a medium supplemented with repressor...

Regulation of Transaminase C Synthesis in Escherichia coli: Conditional Leucine Auxotrophy

McGilvray, Derek; Umbarger, H. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1974 EN
Relevância na Pesquisa
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The regulation of synthesis of the valine-alanine-α-aminobutyrate transaminase (transaminase C) was studied in Escherichia coli mutants lacking the branched-chain amino acid transaminase (transaminase B). An investigation was made of two strains, CU2 and CU2002, each carrying the same transaminase B lesion but exhibiting different growth responses on a medium supplemented with branched-chain amino acids. Both had the absolute isoleucine requirement characteristic of ilvE auxotrophs, but growth of strain CU2 was stimulated by valine, whereas that of strain CU2002 was markedly inhibited by valine. Strain CU2002 behaved like a conditional leucine auxotroph in that the inhibition by valine was reversed by leucine. Results of enzymatic studies showed that synthesis of transaminase C was repressed by valine in strain CU2002 but not in strain CU2. Inhibition by valine in strain CU2002 appears to be the combined effect of repression on transaminase C synthesis and valine-dependent feedback inhibition of α-acetohydroxy acid synthase activity, causing α-ketoisovalerate (and hence leucine) limitation. The ilvE markers of strains CU2 and CU2002 were each transferred by transduction to a wild-type genetical background. All ilvE recombinants from both crosses resembled strain CU2002 and were inhibited by valine in the presence of isoleucine. Thus...

Structural Genes for a Newly Recognized Acetolactate Synthase in Escherichia coli K-12

Felice, Maurilio De; Guardiola, John; Esposito, Bruno; Iaccarino, Maurizio
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1974 EN
Relevância na Pesquisa
166.21578%
Evidence is reported that shows the presence in Escherichia coli K-12 of a newly found acetolactate synthase. This enzyme is the product of two genes, ilvH and ilvI, both located very close to leu. Amber mutations have been found in both genes and therefore their products are polypeptides. Mutations in the ilvH gene cause the appearance of an acetolactate synthase activity which is relatively resistant to valine inhibition and can be separated by adsorption on hydroxylapatite from another activity present in the extract and more sensitive to valine inhibition than the former. A mutant altered in the ilvI gene was isolated among the revertants sensitive to valine inhibition of an ilvH mutant. Such a mutant lacks the resistant acetolactate synthase. A temperature-sensitive revertant of the ilvI mutant contained a temperature-sensitive acetolactate synthase. Thus ilvI is the structural gene for a specific acetolactate synthase. The activity of the ilvH gene product has been measured by adding an extract containing it to a purified ilvI acetolactate synthase, which, upon incubation, became more sensitive to valine inhibition. Conversely, a valine-sensitive acetolactate synthase (the product of the ilvH and the ilvI genes) became more resistant to valine inhibition upon incubation with an extract of a strain containing a missense ilvH gene product.

Escherichia coli K-12 Mutants Altered in the Transport of Branched-Chain Amino Acids

Guardiola, John; Iaccarino, Maurizio
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1971 EN
Relevância na Pesquisa
171.64332%
Two mutants of Escherichia coli K-12 are described which are resistant to the inhibition that valine exerts on the growth of E. coli. These mutants have lesions at two different loci on the chromosome. One of them, brnP, is linked to leu (87% cotransduction) and is located between leu and azi represented on the map at 1 min; the other, brnQ, is linked to phoA (96% cotransduction), probably between proC and phoA and represented at 10 min. These mutants are resistant to valine inhibition but are sensitive to dipeptides containing valine. Since it is known that dipeptides are taken up by E. coli through a transport system(s) different from those used by amino acids, this sensitivity to the peptides suggests an alteration in the active transport of valine. The mutants are resistant to valine only if leucine is present in the growth medium; the uptake of valine is less in both mutants than it is in wild-type E. coli, and it is reduced even further if leucine is present. Under these conditions the total uptake of valine is almost completely abolished in the brnQ mutant. The brnP mutant takes up about 60% as much valine as does the wild type, but no exogenous valine is incorporated into proteins. The apparent Km and Vmax of isoleucine, leucine...

Oxidation of d-Amino Acids by a Particulate Enzyme from Pseudomonas aeruginosa

Marshall, Vincent P.; Sokatch, John R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1968 EN
Relevância na Pesquisa
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A particulate d-amino acid dehydrogenase has been partially purified from cell free extracts of Pseudomonas aeruginosa grown on dl-valine as the source of carbon and energy. A standard assay was developed which utilized 2,6-dichlorophenol-indophenol as the electron acceptor. The pH optimum for enzyme activity ranged from 6.0 to 8.0, depending on the amino acid assayed. The enzyme was most active with monoamino-monocarboxylic amino acids and histidine. The Michaelis constant for d-phenylalanine was found to be 1.3 × 10-3m d-phenylalanine. Constants could not be calculated for the other amino acids oxidized because anomalous plots of V as a function of V/S were obtained. Spectra of enzyme preparations reduced with d-valine or sodium hydrosulfite exhibited adsorption bands typical of the α, β, and γ bands of cytochromes as well as bleaching in the flavin region of the spectrum. When dl-valine was added to a medium with glycerol as the energy source, d-amino acid dehydrogenase was detected after the addition of valine and was produced at a rate directly proportional to the synthesis of total protein. The enzyme was formed when d-valine, l-valine, or dl-alanine was the source of carbon and energy, but not when glucose, glycerol, or succinate was the energy source.

Biological fate of amino acid, peptide and protein hydroperoxides.

Fu, S; Gebicki, S; Jessup, W; Gebicki, J M; Dean, R T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/11/1995 EN
Relevância na Pesquisa
170.11082%
In the course of searching for a suitable marker for studying protein oxidation, we have successfully elucidated the structures of three valine hydroperoxides, i.e. beta-hydroperoxyvaline, (2S,3S)-gamma-hydroperoxyvaline and (2S,3R)-gamma-hydroperoxyvaline, which are novel products of protein oxidation. The corresponding valine hydroxides were obtained by sodium borohydride reduction [Fu, Hick, Sheil and Dean (1995) Free Rad. Biol. Med. 19, 281-292]. We hypothesized that valine hydroxides might be the major biological degradation products of valine hydroperoxides and, as such, could be useful markers for the study of protein oxidation in vivo. The aim of this study was to investigate the fate of valine hydroperoxide in selected biological systems by the use of chemiluminescence detection of hydroperoxides and HPLC analysis of O-phthaldialdehyde derivatives of amino acid residues. The degradation of hydroperoxides present on gamma-radiolysed solutions of valine, Pro-Val-Gly, or BSA occurred in the presence of: (1) transition metals (Fe2+, Fe3+, or Cu2+), (2) the detoxifying enzyme GSH peroxidase, (3) human plasma, and (4) J774 mouse monocyte macrophage cells. The major degradation product of valine hydroperoxide recovered in each case was found to be a valine hydroxide. These results suggest that valine hydroxide (derived from the hydroperoxide) may well be a useful in vivo marker for studying protein damage under oxidative stress.

Biosynthesis of peptides containing α-aminoadipic acid and cysteine in extracts of a Cephalosporium sp

Loder, P. Bronwen; Abraham, E. P.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1971 EN
Relevância na Pesquisa
167.8308%
1. Three intracellular peptides found in small amount in a Cephalosporium sp. were rapidly labelled when dl-[14C]valine was added to a shaken suspension of the organism. More 14C was incorporated into peptide P3, δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine, than into peptide P2 (containing α-aminoadipic acid, cysteine, valine and glycine) or peptide P1 (containing β-hydroxyvaline in place of the valine in peptide P2). 2. Peptides P3 and P2, but not peptide P1 were formed in a broken-cell system from the Cephalosporium sp. in the presence of δ-(l-α-aminoadipyl)-l-cysteine and dl-[14C]valine. No synthesis was observed in the presence of δ-(d-α-aminoadipyl)-l-cysteine or of dl-α-amino[14C]adipic acid and l-cysteinyl-l-valine or l-cysteinyl-d-valine. 3. The biosynthesis of these peptides was catalysed by the particulate fraction of the broken-cell system, whereas that of glutathione was catalysed by the supernatant fraction. 4. These results are discussed in relation to penicillin N and cephalosporin C biosynthesis.

The initiation of haemoglobin synthesis in rabbit reticulocytes

Rahamimoff, Hannah; Arnstein, H. R. V.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1969 EN
Relevância na Pesquisa
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1. The incorporation of labelled valine by rabbit reticulocytes into the N-terminal position of nascent haemoglobin was investigated by deaminating the nascent peptides with nitrous acid and isolating labelled α-hydroxyisovaleric acid and valine after acid hydrolysis. 2. The amount of radioactivity in α-hydroxyisovaleric acid relative to that in valine indicated the presence of 12·3% N-terminal valine having a free amino group. This high value suggests that most if not all nascent peptides contain valine in the N-terminal position. 3. Cell-free preparations containing reticulocyte ribosomes and pH5 enzymes incorporated α-hydroxy-[14C]isovaleryl-tRNA (where tRNA refers to transfer RNA), which was obtained by deamination of [14C]valyl-tRNA from yeast or liver with nitrous acid, into both soluble and nascent protein. 4. When the soluble protein was chromatographed on CM-cellulose, radioactivity was found to be associated with both the α-and β-globin chains. 5. The kinetics of hydrolysis of [14C]valine, was also investigated. Most of the material was hydrolysed rapidly at pH10, but a minor component that was relatively stable appeared to be present to the extent of about 10% of the total valyl-tRNA. Valine was, however, the only hydrolysis product detected by paper chromatography. 6. It is concluded that chain initiation in haemoglobin synthesis involves valine as the N-terminal amino acid and that the amino group of nascent protein is probably not substituted.

Cytocidal amino acid starvation of Saccharomyces cerevisiae and Candida albicans acetolactate synthase (ilv2Δ) mutants is influenced by the carbon source and rapamycin

Kingsbury, Joanne M.; McCusker, John H.
Fonte: Society for General Microbiology Publicador: Society for General Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2010 EN
Relevância na Pesquisa
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The isoleucine and valine biosynthetic enzyme acetolactate synthase (Ilv2p) is an attractive antifungal drug target, since the isoleucine and valine biosynthetic pathway is not present in mammals, Saccharomyces cerevisiae ilv2Δ mutants do not survive in vivo, Cryptococcus neoformans ilv2 mutants are avirulent, and both S. cerevisiae and Cr. neoformans ilv2 mutants die upon isoleucine and valine starvation. To further explore the potential of Ilv2p as an antifungal drug target, we disrupted Candida albicans ILV2, and demonstrated that Ca. albicans ilv2Δ mutants were significantly attenuated in virulence, and were also profoundly starvation-cidal, with a greater than 100-fold reduction in viability after only 4 h of isoleucine and valine starvation. As fungicidal starvation would be advantageous for drug design, we explored the basis of the starvation-cidal phenotype in both S. cerevisiae and Ca. albicans ilv2Δ mutants. Since the mutation of ILV1, required for the first step of isoleucine biosynthesis, did not suppress the ilv2Δ starvation-cidal defects in either species, the cidal phenotype was not due to α-ketobutyrate accumulation. We found that starvation for isoleucine alone was more deleterious in Ca. albicans than in S. cerevisiae...

Bolus ingestion of individual branched-chain amino acids alters plasma amino acid profiles in young healthy men

Matsumoto, Takuya; Nakamura, Koichi; Matsumoto, Hideki; Sakai, Ryosei; Kuwahara, Tomomi; Kadota, Yoshihiro; Kitaura, Yasuyuki; Sato, Juichi; Shimomura, Yoshiharu
Fonte: Springer International Publishing Publicador: Springer International Publishing
Tipo: Artigo de Revista Científica
Publicado em 17/01/2014 EN
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Physiological conditions in humans affect plasma amino acid profiles that might have potential for medical use. Because the branched-chain amino acids (BCAAs) leucine, isoleucine and valine are used as medicines and supplements, we investigated the acute effects of individual BCAAs (10–90 mg/kg body weight) or mixed BCAAs ingested as a bolus on plasma amino acid profiles in young healthy men. Plasma leucine levels rapidly increased and peaked around 30 min after leucine ingestion. Concentrations of plasma isoleucine, valine and phenylalanine subsequently decreased after ingestion, and those of methionine and tyrosine tended to decrease. The effects of ingested leucine on other plasma amino acids were biphasic, being higher at lower doses (10–20 mg/kg body weight). Isoleucine or valine intake also caused corresponding plasma amino acid concentrations to rapidly elevate, and peaks at 30–40 min after ingestion were much higher than that of plasma leucine after leucine ingestion. However, the increase in plasma isoleucine and valine concentrations essentially did not affect those of other plasma amino acids. The rate of decline among peak plasma BCAA concentrations was the highest for leucine, followed by isoleucine and valine. Oral mixed BCAAs promoted the decline in plasma isoleucine and valine concentrations. These results suggest that plasma leucine is a regulator of the plasma concentrations of BCAAs...

Structure-fonction de MARCH1, une E3 ubiquitine ligase régulant la présentation antigénique par le CMH II

Bourgeois-Daigneault, Marie-Claude
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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Les molécules classiques du CMH de classe II sont responsables de la présentation de peptides exogènes par les cellules présentatrices d’antigène aux lymphocytes T CD4+. Cette présentation antigénique est essentielle à l’établissement d’une réponse immunitaire adaptative. Cependant, la reconnaissance d’auto-antigènes ainsi que l’élimination des cellules du Soi sont des problèmes à l’origine de nombreuses maladies auto-immunes. Notamment, le diabète et la sclérose en plaque. D’éventuels traitements de ces maladies pourraient impliquer la manipulation de la présentation antigénique chez les cellules dont la reconnaissance et l’élimination engendrent ces maladies. Il est donc primordial d’approfondir nos connaissances en ce qui concerne les mécanismes de régulation de la présentation antigénique. La présentation antigénique est régulée tant au niveau transcriptionnel que post-traductionnel. Au niveau post-traductionnel, diverses cytokines affectent le processus. Parmi celles-ci, l’IL-10, une cytokine anti-inflammatoire, cause une rétention intracellulaire des molécules du CMH II. Son mécanisme d’action consiste en l’ubiquitination de la queue cytoplasmique de la chaîne bêta des molécules de CMH II. Cette modification protéique est effectuée par MARCH1...

NSC197197; tert-Butoxycarbonyl-L-valine; tert-Butoxycarbonylvaline; L-Valine, N-[(1,1-dimethylethoxy)carbonyl]- (9CI); N-tert-Butoxycarbonyl-L-valine; N-tert-Butoxycarbonylvaline; N-tert-Butyloxycarbonyl-L-valine; N-[(1, 1-Dimethylethoxy)carbonyl]-L-valine; Valine, N-carboxy-, N-tert-butyl ester, L- (8CI)

US National Cancer Institute
Fonte: Unilever Center for Molecular Informatics, Cambridge University Publicador: Unilever Center for Molecular Informatics, Cambridge University
Tipo: Outros Formato: 5662 bytes; 5500 bytes; chemical/x-cml; chemical/x-cml
EN_GB
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Polymorphisms of CYP1A1 I462V and GSTM1 genotypes and lung cancer susceptibility in Mongolian

Fuhou Chang; Zhi-Xie Zhang; Jia Ma; Jun QI; Min-jie Wang; Qin Yin; Guang Wang
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
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Aim: To study the genotype of cytochrome P450 1A1(CYP1A1) I462V and glutathions S-transferase M1( GSTM1) and the relationship of the genetic polymorphism of them with the susceptibility of lung cancer in Mongolia of China. Methods: Allele-specific PCR and a multiplex PCR were employed to identify the genotypes of I462V of CYP1A1 and GSTM1 in a case-control study of 210 lung cancer patients with bronchoscopy diagnosis and 210 matched controls free of malignancy. Results: The frequencies of the variant CYP1A1(Val/Val) genotypes and GSTM1(-) in lung cancer groups were higher than that in control groups (15.24% vs 7.4% and 56.67% vs 40.95% ). The individuals who carried with CYP1A1(Val/Val) or GSTM1(-) genotype had a significantly higher risk of lung cancer, the OR is 2.56 and 1.89 respectively. Stratified histologically the relative risk increased to 2.6 - fold when the patients carried with two valine alleles than the ones carried one valine allele in cases of SCC. GSTM1(-) genotype is the risk factor of SCC (OR=2.39) and AC(OR=2.16). The presence of at least one Val allele of CYP1A1 and GSTM1(-), the risk of lung cancer was increased, the OR was 4.15 for one Val allele and GSTM1(-) and 2.67 for two Val alleles and GSTM1 Considering ages and smoking status...