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Free amino acids of Tronchuda Cabbage (Brassica oleracea L. Var. costata DC): influence of leaf position (internal or external) and collection time

Oliveira, Andreia P.; Pereira, D.M.; Andrade, P.B.; Valentão, P.; Sousa, C.; Pereira, J.A.; Bento, Albino; Rodrigues, M.A.; Seabra, R.M.; Silva, B.M.
Fonte: ACS Publicador: ACS
Tipo: Artigo de Revista Científica
Português
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96.18%
The free amino acid profile of 18 samples of tronchuda cabbage (Brassica oleracea L. var. costata DC) leaves, harvested at three different months, was determined by HPLC/UV?vis. The tronchuda cabbage leaves total free amino acid content varied from 3.3 to 14.4 g/kg fresh weight. Generally, arginine was the major compound, followed by proline, threonine, glutamine, cysteine, and glutamic acid. This study indicates that free amino acids are not similarly distributed: in external leaves, proline and arginine were the major free amino acids, while in internal ones, arginine was the main free amino acid, followed by threonine, glutamine, and cysteine. Significant differences were observed for valine, proline, arginine, leucine, cysteine, lysine, histidine, and tyrosine contents. The levels of some free amino acids were significantly affected by the collection period. In external leaves, this occurred with glutamic acid, serine, valine, leucine, cysteine, and ornithine contents, while in internal leaves, it occurred with aspartic acid, arginine, and total contents.

Comparative study on free amino acid composition of wild edible mushroom species

Ribeiro, Bárbara; Andrade, P.B.; Silva, B.M.; Baptista, Paula; Seabra, R.M.; Valentão, P.
Fonte: ACS Publications Publicador: ACS Publications
Tipo: Artigo de Revista Científica
Português
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86.09%
A comparative study on the amino acid composition of 11 wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, and Cantharellus cibarius) was developed. To define the qualitative and quantitative profiles, a derivatization procedure with dabsyl chloride was performed, followed by HPLC-UV-vis analysis. Twenty free amino acids (aspartic acid, glutamic acid, asparagine, glutamine, serine, threonine, glycine, alanine, valine, proline, arginine, isoleucine, leucine, tryptophan, phenylalanine, cysteine, ornithine, lysine, histidine, and tyrosine) were determined. B. edulis and T. equestre were revealed to be the most nutritional species, whereas F. hepatica was the poorest. The different species exhibited distinct free amino acid profiles. The quantification of the identified compounds indicated that, in a general way, alanine was the major amino acid. The results show that the analyzed mushroom species possess moderate amino acid contents, which may be relevant from a nutritional point of view because these compounds are indispensable for human health. A combination of different mushroom species in the diet would offer good amounts of amino acids and a great diversity of palatable sensations

Fluorimetric determination of intra- and extracellular free amino acids in the microalgae Tetraselmis gracilis (Prasinophyceae) using monolithic column in reversed phase mode

PENTEADO, Jose Carlo Pires; RIGOBELLO-MASINI, Marilda; LIRIA, Cleber Wanderlei; MIRANDA, M. Teresa Machini; MASINI, Jorge Cesar
Fonte: WILEY-V C H VERLAG GMBH Publicador: WILEY-V C H VERLAG GMBH
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
86.07%
This paper describes the development and application of an RP HPLC method using a C(18) monolithic stationary phase for the separation and quantification of extra- and intracellular amino acids in a batch cultivation of the marine alga Tetraselmis gracilis. Fluorimetric detection was made after separation of the o-phthaldialdehyde 2-mercaptoethanol (OPA-2MCE) derivatives using a binary gradient elution. Separation of 19 amino acids was achieved with resolution >1.5 in about 39 min at a flow rate of 1.5 mL/min. RSD of analyses in seawater medium ranged from 0.36% for Orn (0.50 mu mol/L) to 12% for Ile (0.10 mu mol/L). The main constituents of the intracellular dissolved free amino acids (DFAAs) in the exponential growth phase were arginine (Arg), asparagine (Asn), alanine (Ala), aspartic acid (Asp), glutamic acid (Glu), serine (Ser), glycine (Gly), glutamine (Gln), and leucine (Leu). The major amino acids excreted to the media were valine (Val), Ala, Ser, and Gly. The monolithic phase facilitates the analysis by shortening the separation time and saving solvents and instrumentation costs (indeed conventional HPLC instrumentation can be used, running at lower pressures than those ones used with packed particle columns).; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Conselho Nacional de Desenvolvintento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Implementing stepwise solvent elution in sequential injection chromatography for fluorimetric determination of intracellular free amino acids in the microalgae Tetraselmis gracilis

RIGOBELLO-MASINI, Marilda; PENTEADO, Jose C. P.; LIRIA, Cleber W.; MIRANDA, M. Teresa M.; MASINI, Jorge C.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
86.07%
The concept of sequential injection chromatography (SIC) was exploited to automate the fluorimetric determination of amino acids after pre-column derivatization with ophthaldialdehyde (OPA) in presence of 2-mercaptoethanol (2MCE) using a reverse phase monolithic C(18) stationary phase. The method is low-priced and based on five steps of isocratic elutions. The first step employs the mixture methanol: tetrahydrofuran: 10 mmol L(-1) phosphate buffer (pH 7.2) at the volumetric ratio of 8:1:91; the other steps use methanol: 10 mmol L-1 phosphate buffer (pH 7.2) at volumetric ratios of 20:80, 35:65, SO:SO and 65:35. At a flow rate of 10 mu L s(-1) a 25 mm long-column was able to separate aspartic acid (Asp), glutamic acid (Glu), asparagine (Asn), serine (Ser), glutamine (Gln), glycine (Gly), threonine (Thr), citruline (Ctr), arginine (Arg), alanine (Ala), tyrosine (Tyr), phenylalanine (Phe), ornithine (Orn) and lysine (Lys) with resolution >1.2 as well as methionine (Met) and valine (Val) with resolution of 0.6. Under these conditions isoleucine (Ile) and leucine (Leu) co-eluted. The entire cycle of amino acids derivatization, chromatographic separation and column conditioning at the end of separation lasted 25 min. At a flow rate of 40 mu L s(-1) such time was reduced to 10 min at the cost of resolution worsening for the pairs Ctr/Arg and Orn/Lys. The detection limits varied from 0.092 mu mol L(-1) for Tyr to 0.51 mu mol L(-1) for Orn. The method was successfully applied to the determination of intracellular free amino acids in the green alga Tetraselmis gracilis during a period of seven days of cultivation. Samples spiked with known amounts of amino acids resulted in recoveries between 94 and 112%. (C) 2008 Elsevier B.V. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análises das variações fitoquímicas, estruturas genética e importância econômica de Annona crassiflora Mart., no cerrado; Analysis of phytochemical variation, genetic structure and economic importance of Annona crassiflora Mart., in cerrado

Egydio, Anary Priscila Monteiro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/04/2009 Português
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66.16%
A Annona crassiflora Mart. é uma espécie frutífera nativa do cerrado que possui alto potencial de uso e ampla distribuição. O presente trabalho tem os seguintes objetivos: identificar e quantificar aminoácidos livres, carboidratos solúveis e ácidos graxos da polpa e das sementes, visando ampliar os conhecimentos sobre potencial econômico de A. crassiflora; avaliar qual o nível de variações quantitativas e qualitativas de alcalóides de A. crassiflora de amostras provenientes de diferentes regiões do cerrado; avaliar qual a magnitude da diversidade genética entre diferentes populações de A. crassiflora, utilizando marcadores isoenzimáticos. Com relação às propriedades nutricionais, as análises de aminoácidos livres, carboidratos e lipídeos foram feitas por CLAE/F, por CLAE/CTI - DPA e por CG/EM, respectivamente. O teor total de aminoácidos livres na polpa variou de 1101,99 g/g a 1975,7 g/g de massa seca, enquanto nas sementes variou de 636,3 ?g/g a 17.445,83 ?g/g de massa seca. A glutamina foi majoritária em todas as amostras. O teor total dos carboidratos solúveis da polpa variou de 11,5 g/100g a 17,03 g/100g e das sementes variou de 13,69 g/100g a 40,47 g/100g de matéria seca. Foram detectadas a frutose...

Aminoácidos como coadjuvantes da adubação foliar e do uso do glifosato na cultura de soja; Amino acids addition to foliar fertilization and use of glyphosate in soybean

Lambais, George Rodrigues
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 17/06/2011 Português
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76.04%
Este trabalho teve como objetivo avaliar a influência dos fertilizantes foliares a base de aminoácidos livres na utilização conjunta de práticas agrícolas como a aplicação de glifosato e a adubação no solo com P e K em soja BRS 255 RR. As avaliações foram realizadas nos parâmetros biométricos, nutricionais, metabólicos e produtivos através das variáveis: altura, valor SPAD (clorofilas), área foliar, biomassa aérea (massa fresca e seca de folhas e caules), macronutrientes e micronutrientes nas folhas, atividade da nitrato redutase (NR), glutamina sintetase (GS), concentração de proteínas totais solúveis (PTS), número de vagens, massa fresca e seca de vagens, massa média de 100 grãos, massa total de grãos, teores de lipídeos e proteínas acumulados nos grãos. Foram conduzidos dois experimentos em paralelo, com os produtos Ajifol e Flororgan, em ambiente natural utilizando vasos de polietileno com capacidade para 20 litros. O delineamento utilizado foi em blocos casualizados, onde cada unidade experimental foi constituída de três plantas de soja por vaso preenchido com 20 kg de substrato (Latossolo vermelho distrófico argiloso). A adubação no solo com P e K (1,00 e 0,24 g kg-1, respectivamente) foi realizada 30 dias antes da semeadura. As aplicações do Ajifol (1...

Concentrações de ácidos graxos e de aminoácidos em tecido tumoral e tecido normal adjacente de pacientes com carcinoma espinocelular de mucosa de cabeça e pescoço; Fatty acids and amino acids concentrations in tumoral and adjacent normal tissue of patients with squamous cell carcinoma of the head and neck

Leme, Izabel de Arruda
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 02/12/2008 Português
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76.14%
A alta taxa de replicação celular no tumor, aumenta a demanda de ácidos graxos para composição de membrana e de nucleotídeos para síntese de DNA. Visto que a síntese de ambos depende de intermediários do ciclo de Krebs e que no tumor a maior parte da glicose disponível é convertida a ácido lático (e não a acetil-coA, como ocorre na célula normal), a glutamina passa a ser a principal fonte de intermediários do ciclo de Krebs para síntese de ácidos graxos e de nucleotídeos. Além da glutamina, outros aminoácidos têm seu metabolismo alterado no tumor. Assim, os objetivos do trabalho foram comparar o perfil de ácidos graxos e de aminoácidos em tecido tumoral e tecido normal adjacente de pacientes com carcinoma espinocelular de mucosa de cabeça e pescoço, quantificar lipídeos totais nas amostras e avaliar o estado nutricional dos pacientes. Participaram da pesquisa pacientes internados junto ao Serviço de Cirurgia de Cabeça e Pescoço do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto-USP. As amostras de tecido tumoral e de tecido normal foram coletadas durante procedimento cirúrgico, após excisão do tumor. A extração dos lipídeos e dos aminoácidos livres foi realizada pelo método de Folch. A determinação de ácidos graxos livres e totais foi realizada por cromatografia gasosa/espectrometria de massa. A análise de aminoácidos foi realizada por cromatografia gasosa com detector de chama. A avaliação nutricional incluiu: aferição de peso...

Influence of free amino acids on clavulanic acid production by Streptomyces clavuligerus in synthetic medium

Trovatti, Eliane; Badino, Alberto Colli; Hokka, Carlos Osamu; Gonsales da Costa Araujo, Maria Lucia
Fonte: Inst Tecnologia Parana Publicador: Inst Tecnologia Parana
Tipo: Artigo de Revista Científica Formato: 173-179
Português
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75.97%
The effect of nitrogen source on clavulanic acid production was investigated in shake flasks. Media containing asparagine plus one of several different amino acids or a combination of two amino acids was tested. The best result, ca. 180 mg/L clavulanic acid, CA, in 60 h, was obtained with the lysine-tyrosine pair In an aerated and agitated fermentor this medium led to CA concentrations of ca. 210 mg/L, a remarkable production for synthetic medium utilization. Amino acids analysis during cultivation indicated that, while asparagine was consumed rapidly, lysine and tyrosine were metabolized slowly, promoting CA production.

Association of free amino acids with caries experience and mutans streptococci levels in whole saliva of children with early childhood caries

Fonteles, Cristiane S. R.; Guerra, Milene H.; Ribeiro, Thyciana R.; Mendonca, Danielle N.; de Carvalho, Cibele B. M.; Monteiro, Andre J.; Toyama, Daniela O.; Toyama, Marcos H.; Fonteles, Manasses C.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 80-85
Português
Relevância na Pesquisa
86.11%
Objective: The aim of the present study was to identify the free amino acid content in whole saliva of children with (CE) and without early childhood caries (CF) (ECC), correlating these findings with caries experience and mutans streptococci (MS) levels in saliva.Design: Seventy-eight healthy children, both genders, 6-71 months age, were selected to participate in the study. Following examination for dmft scores calculation, unstimulated whole saliva was collected from all 78 participants, stored at -80 degrees C, and used for amino acid analysis, on a Biochem 20 plus amino acid analyzer. Stimulated whole saliva was collected from 52 children, transported, diluted and plated on MSB agar medium for detection of MS in cfu/mL.Results: Forty different free amino acids were identified in whole saliva, with great variation in their concentration. A statistically significant relation was found between caries experience and the presence of free proline and glycine. While proline (p = 0.0182) was more frequently absent in the CF group, the absence of glycine (p = 0.0397) was more often observed in the CE group. In the presence of higher levels of MS, free glycine reduced the risk of experiencing dental caries (p = 0.0419). Conversely, the presence of proline was found to increase the risk of experiencing the disease (p = 0.0492).Conclusions: The presence of free proline and absence of free glycine in children with ECC...

Effects of intrauterine malnutrition on brain free amino acids of young rats, after nutritional recovery during lactation period

Trindade, C. E P; De Nobrega, F. J.; Tonete, S. S Q
Tipo: Artigo de Revista Científica Formato: 795-800
Português
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76.04%
The effect of protein-calorie malnutrition during gestation on the brain amino acids of rat pups was studied following nutritional recovery during lactation. The brain amino acids of rat pups born to dam rats malnourished during gestation were studied after these rat pups received proper nutrition during lactation. Pregnant rats were fed a 1% protein diet with total caloric intake restricted to half that of controls. After birth, the offspring of rats fed on deficient diets were nurtured up to the 28th day postpartum by foster mothers receiving adequate diets. At this time, the offspring were killed. The control group consisted of offspring from pregnant rats fed a diet with adequate protein (21%) and calories during the entire gestation and lactation period. Quantitation of brain amino acids in the pups at 28 days postpartum showed lower concentrations of essential and nonessential amino acids in the rats malnourished during gestation. Concentrations of histidine, glycine, and ?-aminobutyric acids were all reduced. These findings demonstrate that the brains of rat pups malnourished during gestation show persistent decreases in specific brain amino acids after adequate postpartum nutrition.

Lipoic acid and ascorbic acid affect plasma free amino acids selectively in the teleost fish pacu (Piaractus mesopotamicus)

Terjesen, Bendik F.; Park, Kwan; Tesser, Marcelo B.; Portella, Maria C.; Zhang, Yongfang; Dabrowski, Konrad
Tipo: Artigo de Revista Científica Formato: 2930-2934
Português
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Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied...

Free Amino Acids in Pacu, Piaractus mesopotamicus, Eggs and Larvae

Portella, M. C.; Takata, R.; Leitão, N. J.; Menossi, O. C.; Kwasek, K.; Dabrowski, K.
Tipo: Artigo de Revista Científica Formato: 425-434
Português
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Free amino acids (FAA) are used principally as substrate in protein synthesis and the source of energy in aerobic catabolism. In marine fish, embryo and larvae FAA are used to maintain body fluid osmolality during fish early development. However, there is essentially no information about FAA concentrations in early ontogeny of freshwater neotropical species in comparison to marine fishes. Therefore, the aim of this study was to evaluate the FAA concentrations in pacu, Piaractus mesopotamicus, eggs and larvae. Broodstock fish were induced to spawn and ovulated females were stripped of their eggs and immediately sampled for analysis. Larvae were sampled right after hatching (HL) and after the completion of the yolk-sac absorption (YSA). The wet weight of the HL and YSA larvae amounted to 0.5±0.1mg and 1.1±0.3mg, respectively. HL larvae showed higher levels of most of the indispensable amino acids (IAA) in comparison to eggs and YSA larvae. Exceptions were observed with His and Trp that showed higher or similar levels, respectively, in YSA larvae. The FAA Orn, Tau, Glu, Gln, Gly, and Tyr increased concentrations in both larval stages while that of Tau was found in higher concentration in all analyzed stages. Also, the concentrations of Asn...

Free amino acids and biogenic amines in wines and musts from

Herbert, Paulo; Cabrita, Maria João; Ratola, Nuno; Laureano, Olga; Alves, Arminda
Tipo: Artigo de Revista Científica Formato: 306271 bytes; application/pdf
Português
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75.94%
Characterization of musts and wines from different Alentejo sub-regions, varieties and vintages was made in terms of amino acid and amine contents, by HPLC with fluorescence detection of OPA/FMOC derivatives. The evolution of volatile and biogenic amines was also studied throughout 10 microvinifications. No significant increase in the levels of total volatile amines was observed during alcoholic or spontaneous malolactic fermentation. While higher histamine levels were only found during the storage period, an increase in the concentration of tyramine was confirmed in red wines immediately after malolactic fermentation, which seems to be also the main origin of putrescine. It was noticed that grape variety, region of production, and vintage can influence free amino acid and amine contents of musts and wines, although alcoholic and malolactic fermentations can override that effect.

Relationship Between Biogenic Amines and Free Amino Acid Contents of Winesand Musts from Alentejo (Portugal)

Herbert, Paulo; Cabrita, Maria Joao; Ratola, Nuno; Laureano, Olga; Alves, Arminda
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.04%
The concentration of biogenic amines and free amino acids was studied in 102 Portuguese wines and 18 musts from Alentejo demarcated (D.O.C.) regions. Most wines were commercial, except for 38 monovarietals obtained by micro vinification. Musts from the varieties used to produce the latter wines were also studied. Both biogenic amines and free amino acids were analyzed by HPLC using fluorescence detection for their o-phthalaldehyde/fluorenylmethyl chloroformate (OPA/FMOC) derivatives. The most significant amines (average 10.8 mg/L for histamine+tyramine in red, and 7.4 mg/L for white wines) were found to be present at low levels and, although no important relationship between each individual biogenic amine could be obtained, the total amine content depends significantly on the assimilable amino acid content in wine.

Using a medium of free amino acids to produce penicillin g acylase in fed-batch cultivations of Bacillus megaterium ATCC 14945

Silva,R. G.; Souza,V. R.; Nucci,E. R.; Pinotti,L. M.; Cruz,A. J. G.; Giordano,R. C.; Giordano,R. L.C.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2006 Português
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86.08%
The production of penicillin G acylase (PGA, an important industrial enzyme) from a wild strain of Bacillus megaterium using a pool of free amino acids as substrate was studied in a bench-scale bioreactor. Experiments carried out in shakers showed that the substitution of casein for free amino acids in the presence of cheese whey was the culture medium that provided the highest productivity. Several cultivations were carried out in a bioreactor operated in either batch or fed-batch mode. Batch runs showed that enzyme production is associated with microorganism growth. The following set of amino acids was preferentially consumed: Ala, Arg, Asp, Gly, Lys, Ser, Thr and Trp. On the other hand, the rates of consumption of His, Ile, Leu, Met, Phe, Pro, Tyr and Val were lower.

Compositional changes of proteins and amino acids in germinating coffee seeds

Shimizu,Milton Massao; Mazzafera,Paulo
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2000 Português
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76.11%
Endosperm is the main reserve tissue in coffee seeds. Coffee (Coffea arabica L.) seeds were germinated for six weeks and qualitative and quantitative changes in amino acids and proteins were investigated. The total content of free amino acids were reduced during germination, however, protein content remained constant. SDS-PAGE profiles showed that legumin-like proteins became less stained in the last weeks. Asparagine, glutamic acid, aspartic acid, alanine and lysine were the major free amino acids, although serine and glutamine were also significant. Except for tyrosine, which increased with germination, all other amino acids were reduced. Analysis of the amino acid composition of the total soluble protein showed glutamic acid/glutamine and glycine as the main amino acids. However, other amino acids such as leucine, aspartic acid/asparagine, alanine, lysine, serine were also found in reasonable amounts.

Absorption from a mixture of seventeen free amino acids by the isolated small intestine of the rat.

Gardner, M L
Tipo: text
Publicado em /02/1976 Português
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66.17%
Absorption and secretion from a mixture of seventeen free amino acids has been measured in isolated perfused rat small intestine. 2. The absorption rate of an amino acid from this mixture is proportional to its concentration in the perfusate and independent of its chemical constitution. The constant of proportionality is the same as that previously observed when the perfusate contained peptides as well as amino acids. 3. Amino acids are concentrated, on average, sixfold during passage across the mucosa, and the free amino acid composition of the secretion into the tissue fluid is very similar to that of the luminal perfusate. 4. Peptides do not appear to be added to the tissue fluid during absorption of free amino acids. 5. It is concluded that the mechanisms for absorption of free amino acids are in general independent of those for absorption of peptides.

Influence of the postoperative state on the intracellular free amino acids in human muscle tissue.

Vinnars, E; Bergstöm, J; Fürst, P
Tipo: text
Publicado em /12/1975 Português
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66.17%
Five patients were studied before and two to three days after major, uncomplicated abdominal operation. Muscle tissue was obtained by needle biopsy from m. quadriceps femoris after eight hours overnight fast. Plasma free amino acids were analyzed in simultaneously obtained samples. In the homogenized muscle samples the intracellular concentration of each amino acid (IC) was calculated by subtracting the free extracellular part from the total amount, assuming the plasma concentration to be equal to the concentration in the interstitial fluid. Their relationships have also been calculated (IC/EC gradient). The extra- and intracellular water distribution was estimated using a modified chloride method. In similarity to the findings in normal subjects the majority of the amino acids showed much higher concentration in intracellular water than in plasma. Preoperatively all amino acids examined in muscle biopsies were formed within normal limits. Postoperatively the total amount of free amino acids in plasma and muscle was decreased, and the amino acid profiles differed from those observed in normal subjects. In plasma, as compared with normal controls, the most significant changes were an increase in phenylalanine and tyrosine and a decrease in serine...

Free amino acids as phagostimulants in cricket nuptial gifts: support for the ‘Candymaker’ hypothesis

Warwick, Stuart; Vahed, Karim; Raubenheimer, David; Simpson, Stephen J.
Fonte: The Royal Society Publicador: The Royal Society
Tipo: text
Português
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66.18%
Nuptial gifts that are manufactured by the male are found in numerous insect species and some spiders, but there have been very few studies of the composition of such gifts. If, as has been proposed recently, nuptial gifts represent sensory traps, males will be selected to produce gifts that are attractive to females but such gifts will not necessarily provide the female with nutritional benefits (the ‘Candymaker’ hypothesis). We examined the free amino acid content of the spermatophylax of the cricket Gryllodes sigillatus (Orthoptera: Gryllidae) using high performance liquid chromatography (HPLC). The spermatophylax (dry weight) consisted of approximately 7 per cent free amino acids. The free amino acid composition was highly imbalanced, with a low proportion of essential amino acids (18.7%) and a high proportion of proline and glycine. The main free amino acids found in the spermatophylax appeared to act as phagostimulants: the duration of feeding on artificial gels by females was positively related to the free amino acid content of the gels. The results therefore suggest that males use free amino acids to ‘sweeten’ a relatively low-value food item. A possible function of glycine in inhibiting female movement is also proposed.