Assessment of methionine plus cystine requirement of tambaqui (Colossoma macropomum) based on zootechnical performance, body composition, erythrogram, and plasmatic and hepatic metabolites.

Tambaqui (Colossoma macropomum) is a species of great cultural and economic importance in aquaculture in the Amazon region. Methionine is considered the first limiting sulfur amino acid in practical fish diets, which encourages investigating its use in diets for tambaqui. This study aimed to verify the digestible methionine plus cystine (Met + Cys) requirement in diets for tambaqui (89.52 ± 0.53 g) for 60 days. The treatments investigated were: 6.50, 7.80, 9.10, 10.40, 11.70, and 13.00 g Met + Cys kg diet-1. The estimated requirement based on final weight, weight gain, feed conversion ratio, and specific growth rate was 9.04, 8.92, 8.91, and 8.58 g Met + Cys kg diet-1, respectively, while on body protein deposition, body fat deposition, body ash deposition, and nitrogen retention efficiency was 9.29, 9.20, 9.19, and 8.72 g Met + Cys kg diet-1, respectively. Linear regression demonstrated that increased digestible Met + Cys in the diet decreased plasma total protein, globulin, and liver total protein levels. Quadratic regression showed that the highest value for liver glycogen was found with a 10.40 g Met + Cys kg diet-1. Another quadratic regression demonstrated a lower hepatic aspartate aminotransferase (AST) enzymatic activity in fish fed between 7.80 and 11.70 g Met + Cys kg diet-1. The different treatments did not influence the erythrogram. In conclusion, when considering an integrative view of the results for growth performance, whole-body deposition, and liver parameters without harming the physiological and metabolic status, we recommended choosing a diet with digestible Met + Cys between 8.58 and 9.29 g kg- 1 for tambaqui.

ATP sulfurylase atypical leucine zipper interacts with Cys3 and calcineurin A in the regulation of sulfur amino acid biosynthesis in Cryptococcus neoformans.

Fungal pathogens are a major cause of death, especially among immunocompromised patients. Therapies against invasive fungal infections are restricted to a few antifungals; therefore, novel therapies are necessary. Nutritional signaling and regulation are important for pathogen establishment in the host. In Cryptococcus neoformans, the causal agent of fungal meningitis, amino acid uptake and biosynthesis are major aspects of nutritional adaptation. Disruptions in these pathways lead to virulence attenuation in an animal model of infection, especially for sulfur uptake and sulfur amino acid biosynthesis. Deletion of Cys3, the main transcription factor that controls these pathways, is the most deleterious gene knockout in vitro and in vivo, making it an important target for further application. Previously, we demonstrated that Cys3 is part of a protein complex, including calcineurin, which is necessary to maintain high Cys3 protein levels during sulfur uptake and sulfur amino acid biosynthesis. In the current study, other aspects of Cys3 regulation are explored. Two lines of evidence suggest that C. neoformans Cys3 does not interact with the F-box WD40 protein annotated as Met30, indicating another protein mediates Cys3 ubiquitin degradation. However, we found another level of Cys3 regulation, which involves protein interactions between Cys3 and ATP sulfurylase (MET3 gene). We show that an atypical leucine zipper at the N-terminus of ATP sulfurylase is essential for physical interaction with Cys3 and calcineurin. Our data suggests that Cys3 and ATP sulfurylase interact to regulate Cys3 transcriptional activity. This work evidences the complexity involved in the regulation of a transcription factor essential for the sulfur metabolism, which is a biological process important to nutritional adaptation, oxidative stress response, nucleic acid stability, and methylation. This information may be useful in designing novel therapies against fungal infections.

Partitioning the efficiency of utilization of amino acids in growing broilers: Multiple linear regression and multivariate approaches.

Determining the efficiency of amino acid (AA) utilization in growing animals is crucial to estimate their requirement accurately. In broiler chickens, the composition of AA in feather is different from feather-free body and the proportion of feathers will change along broiler's growth, which may impact the efficiency of utilization on AA consumed. Therefore, in order to establish a method that predicts the efficiency of utilization for feather-free body and feather, two approaches were evaluated: a multiple linear regression and a multivariate analysis. Additionally, a new factorial model was proposed to predict AA requirements in broiler chickens. Data from 13 trials that evaluated the requirements for lysine (Lys), sulphur AA (SAA), threonine (Thr), and valine (Val) in male broilers were used for the analyses. Both methods of analysis were consistent in showing that the efficiency of utilization in feather-free body and feather were different. Using multiple linear regression, the values of efficiency of utilization estimated in feather-free body were 0.68, 0.72, 0.81, 0.79 (mg of amino acid deposited / mg of amino acid consumed above maintenance) and in feather were 0.58, 0.77, 0.78, and 1.57 (mg/mg) for Lys, SAA, Thr, and Val, respectively. Applying the multivariate approach, the corresponding predicted values were 0.68, 0.67, 4.23, 0.27 (mg/mg) in feather-free body and 1.16, 0.86, 0.16, and 1.10 (mg/mg) in feather, respectively. According to the results, efficiency of utilization may be related, to some extent, on the concentration determined in each tissue. The uncertainty around the amount of AA consumed for gain directed to feather-free body or feather deposition could be a limitation for multivariate analyses. The results indicated that multiple linear regression predictions may be better estimates of utilization efficiency. However, more studies are needed to elucidate the effect of age on deposition and partitioning of dietary AA in different parts of the broiler.

Methionine to cystine ratio in the total sulfur amino acid requirements and sulfur amino acid metabolism using labelled amino acid approach for broilers.

BACKGROUND: Assuming that part of Methionine (Met) is converted into Cystine (Cys), but ignoring the rates with which such phenomenon occurs may lead to an excessive supply of Met in poultry diets. Such inconvenient could be easily avoided with the knowledge of the ideal Met:Cys/Total sulfur amino acids (TSAA) ratio and the rates of Met conversion into Cys. RESULTS: Met sources did not affect performance. Met:Cys/TSAA ideal ratio was determined using curvilinear-plateau regression model. Both optimum body weight gain and feed conversion ratio were estimated in 1007 g/day and 1.49, respectively, at 52% Met/TSAA ratio. Feed intake was not affected by Met:Cys/TSAA ratios. In the labelled amino acid assay, the rates with which Met was converted into Cys ranged from 27 to 43% in response to changes in Met:Cys/TSAA ratios, being higher at 56:44. CONCLUSION: Based on performance outcomes, the minimum concentration of Met relative to Cys in diets for broilers from 14 to 28 d of age based on a TSAA basis, is 52% (52:48 Met:Cys/TSAA). The outcomes from labelled amino acid assay indicate that highest the Met supply in diets, the highest is its conversion into Cys.

Consumo dietético, variantes genéticas e relação com níveis sanguíneos de folato, ácido fólico não metabolizado e homocisteína após a fortificação mandatória de ácido fólico: estudo de base populacional - ISA - Capital / Dietary intake and genetic variants of folate and its relation to folate, unmetabolized folic acid and homocysteine blood concentrations after mandoty folic acid fortification population based study ISA-Capital

Em diversos países, inclusive no Brasil, a fortificação de alimentos com ácido fólico (AF) foi adotada como política pública de prevenção e combate à deficiência nutricional da vitamina, motivados principalmente pela redução da incidência dos defeitos do tubo neural. No período pós-fortificação observa-se tanto a evolução positiva do consumo e nível sérico da vitamina quanto a diminuição da concentração plasmática de homocisteína, e ainda, o aumento do ácido fólico não metabolizado na maioria desses países. Não se conhece ainda os efeitos biológicos do AFNM, no entanto, considera-se que o AFNM pode ser um fator relevante nas questões de segurança associadas com alto consumo de AF. Objetivo: Avaliar o consumo dietético e nível de folato, homocisteína e ácido fólico não metabolizado após a fortificação mandatória de alimentos com ácido fólico, e a interação com os polimorfismos envolvidos no metabolismo do folato e homocisteína. Metodologia: Os dados foram oriundos do estudo transversal de base populacional ISA Capital 2008 conduzido em uma amostra representativa de residentes do município de São Paulo, de ambos os sexos, e com idade acima de 14 anos. Coletou-se recordatórios alimentares de 24 horas e amostra de sangue em jejum de 12 horas para análises bioquímicas e moleculares. As análises estatísticas foram realizadas no programa STATA®, versão 13.0, com nível de significância de 5 por cento . Resultados: O estudo foi conduzido em 750 indivíduos, sendo 53,1 por cento mulheres e média de idade 40,7 (IC95 por cento 38,8-42,5) anos. A média de consumo e nível de folato foi de 375,8 (IC95 por cento 363,0-388,6) mcg/dia e 13 (IC95 por cento 12,0-13,9) ng/ml, respectivamente...

Food fortification is an important strategy in public health policy for controlling micronutrient malnutrition, and a major contributory factor in the eradication of micronutrients deficiencies. Motivated by the reduction in the occurrence of neural tube defects, countries worldwide, including Brazil, adopted food fortification with folic acid (FA). Folic acid fortification has increased dietary intakes of folic acid and folate status, but it is also associated with the presence of circulating FA. Although the metabolism and biological effects of circulating of folic acid are not well known, it may be a contributing factor in safety concerns associated with high oral doses of folic acid. Objective: To assess the folate intake and status, homocysteine and circulating FA after mandatory fortification with folic acid, and interaction with polymorphisms involved in 1-carbon metabolism. Material and Methods: Data were from 750 individuals aged > 14 years old who participated of a cross-sectional population-based survey in Sao Paulo City-Brazil. Fasting blood samples and information about food intake based on two measures of 24 hour food recall were collected. All analyses were carried out using STATA (version 13.0) and p-value <.05 was considered to be statistically significant in all tests. Results: Results were from 750 individuals...

Efeito da suplementação de cisteína ou glutamina sobre o metabolisno dos aminoácidos sulfurados e glutationa de pacientes infectados pelo HIV nas condições de jejum e pós-sobrecarga de metionina / Effect of the cysteine or glutamine supplementation on the metabolism of sulphurated amino acids and glutathione state of HIV patients on fasting and after-methionine load

INTRODUÇÃO: Metionina (Met), cisteína (Cys), homocisteína (Hcy) e taurina (Tau) são os qautro aminoácidos sulfurados (AAS), mas apenas a Met e Cys são incorporadas em proteínas. Os três principais produtos dos AAS, glutationa, (GSH), Hcy e Tau influenciam, principalmente, as respostas inflamatória e imune. A Tau e GSH melhoram a inflamação, enquanto que a Hcy apresenta efeito oposto. Os pacientes HIV+ apresentam baixos níveis de GSH e outros nutrientes antioxidantes, mostrando relação direta entre Cys (e GSH) com células CD4 +. Não se conhece o mecanismo pelo qual as mudanças na ingestão dos AAS influenciam este fenômeno e as relações entre Hcy, doenças inflamatórias e alterações in vitro no comportamento das células imunes criou nota cautelar sobre a suplementação de dietas com AAS. OBJETIVOS: investigar as vias dos AAS em pacientes HIV+ nas condições de jejum e pós-sobrecarga de Met frente à dieta habitual (DH) isolada ou acompanhada da suplementação de Cys (NAC) ou glutamina (GIn). MÉTODOS: 12 pacientes HIV+ (6 M e 6 F, de 25 a 36 anos), sob tratamento anti-retroviral pelo esquema tríplice, sem infecções secundárias e 20 controles saudáveis (10 M e 10 F, 23-28 anos) foram randomicamente distribuídos para suplementação com NAC (N-acetilcisteína, 1g/d ou GIn (20 g/d) em estudo cruzado com 7 dias de dieta separados por uma semana de washout (Wo com DH). Amostras de sangue após jejum noturno de 10 a 12 horas foram coletadas antes (MO) e após (M1) cada regime dietético. A seguir, os indivíduos ingeriram metionina (100 mg/kg) com coletas de sangue após 2 e 4 horas para a determinação da área abaixo da curva (AAC)...

Methionine (Met), cysteine (Cys), homocysteine (Hcy), and, taurine (Tau) are the 4 sulfur-containing amino acids (SAA), but only Met and Cys are incorporated into proteins. The 3 major products of SAA, glutathione (GSH), Hcy and Tau influence, mainly, inflammatory and of immune responses. Tau and GSH ameliorate inflammation whereas Hcy has the opposite effect. HIV+ patients present low levelis of GSH and other antioxidants nutrients, showing a direct relationship between Cys (and GSH) with CD4+/ cells. How changes in SAA intake influence this phenomenon is unknown and the relationships among Hcy, inflammatory diseases, and in vitro alterations in immune cell behavior create a cautionary note about supplementation of diets with SAA. OBJECTIVE: To investigate SAA pathways in HIV+ patients on fast and Met-overload (Met-DL) states after taken diet habitual without (HD) or with supplements of Cys (NAC) or glutamine (Gln). METHOOS: 12 HIV+ (6M and 6F, 25-36 yrs old) patients under HAART without secondary infections and 20 healthy (10M and 10F, 23-28 yrs old) controls were randomly assigned to either NAC (N-acetylcysteine, 1g/d) or Gln (20g/d) diets, in a 7-day diet crossover design, separated by a 7-day washout (with HD) period. Blood samples were drawn after overnight fast before (MO) and after each dietary treatments (M1) for the resting measurements. Immediately after blood sampling ali subjects started the Met-DL by ingesting at once 100 mg Met/kg BW and having the blood draw after 2 and 4 hours for the area under the curve (AUC) determination. At MO both groups were assessed for anthropometry (BMI, kg/m2), glomerular (plasma urea and creatinina) and hepatocellular (plasma γGT activity) funetions, nutritional (albumin, calcium, folic acid and vitamin B12) and antioxidant (uric acid, GSH, GSSG, Hey) states, glucose, lipids (triglycerides and cholesterol fractions) and SAA, serine (Ser), glyeine (Gly), glutamate (Glu) and Gln. The HIV+ group was characterized also by viral load, CD4+ and CD8+ counts. The statistical comparisons between groups and among diets showed group homogeneity for 8MI, albumin, calcium, vitamin B12, Hey, HDL-cholesterol, urea and creatinine. The patients presented higher values of glucose, triglycerides, γ-GT, LDL-cholesterol, and GSSG along with lower concentrations of uric acid, GSH and all but Hcy amino acids. The Met-OL equalized (Δ values) the groups for Met, Hcy, Tau and Gln. NAC and Gln diets led the HIV+ group to a higher concentrations of GSH (NAC > Gln) by acting differently on its precursors: Gly (Gln > NAC) and Cys (NAC > Gln), resulting similar consumption of Ser and production of Tau. Both diets reduced GSSG/GSH (NAC > Gln) and only NAC increased (6 x) Hey. The later was worsened by Met-OL. Thus HIV+ results in multiple deficiencies of vitamins and amino acids leading to lower levels of GSH and higher GSSG/GSH ration. The main problems of lower formation of Cys and low ineorporation of Cys and Gly into GSH were greatly solved by giving Met, NAC and Gln to the patients, hence remaining the drawback of increasing Hcy with Met or NAC supplements.

Bases metabólicas da suplementação de cisteína / Metabolic Basis of supplemental cysteine / Metabólicas Bases de cisteína suplementaria

A cisteína (Cys) é um aminoácido sulfurado produzido, endogenamente, a partir da transulfuração da homocisteína. É limitante da síntese da glutationa, principal antioxidante (peroxidase) solúvel no citosol e maior fonte sulfurada endógena. Adicionalmente, a Cys origina a taurina (Tau) com papel neurotransmissor, inativador de ácidos biliares, osmolito intracelular e agente antioxidante intrafagocitário. Apenas o fígado, pãncreas e rins formam Cys a partir da metionina (Met). Nos demais tecidos, a principal fonte de Cys é a sua concentração plasmática ou as de GSH e GSSG (desde que a célula contenha y-glutamil transpeptidase e dipeptidase). A Cys (SH) é instável e se oxida facilmente a cistina (S-S), forma predominante no plasma. As células desprovidas de redutase, como os linfócitos, não convertem a Cis (S-S) a Cys (SH) e tornam-se dependentes da Cys gerada por outras células sanguíneas ou da Cys plasmática. A Cys ativa a proliferação celular e as funções de quimiotaxia, fagocitose e citoxicidade natural (de células malignas). A deficiência de Cys está associada não apenas aos menores níveis de GSH e menor defesa antioxidante, mas também à diminuição de glutamina e consequente deficiência imunitária. Não há recomendações específicas para a Cys.A RDA para Met+Cys é de 17 mg/g...

The cysteine (Cys) is a sulfur-containing amino acid produced endogenously from the transsulfuration of homocysteine. It is limiting the synthesis of glutathione, the main antioxidant (peroxidase) soluble in the cytosol and increased endogenous sulfur source. Additionally, Cys originates taurine (Tau) with paper neurotransmitter inactivation of bile acids, intracellular osmolyte and antioxidant agent intrafagocitário. Only liver, pancreas and kidneys form Cys from methionine (Met). In other tissues, the main source of Cys is its plasma concentration or GSH and GSSG (as long as the cell containing y-glutamyl transpeptidase and dipeptidase). The Cys (SH) is unstable and easily oxidized to cystine (SS), the predominant form in plasma. Cells devoid of reductase, such as lymphocytes, do not convert to Cys (SS) to Cys (SH) and become dependent on Cys generated by other blood cells or plasma Cys. The Cys active cell proliferation and functions of chemotaxis, phagocytosis, and natural cytotoxicity (malignant cells). Cys deficiency is associated not only with lower levels of GSH and lower antioxidant defense, but also to the decrease of glutamine and subsequent immune deficiency. There are no specific recommendations for Cys.A for Met + Cys RDA is 17 mg / g...

Aminoácidos plasmáticos en pacientes con neuropatía epidémica diagnósticados en Cuba / Plams amino acids in patients to whom epidemic neuropathy was diagnosed in Cuba

En los últimos años los estudios en pacientes con neuropatías han revelado cambios bioquímicos importantes que han explicado la pérdida de la visión por lesiones del nervio óptico con desmielización al nivel de la zona axial del nervio y en la cual los aminoácidos azufrados desempeñan un importante papel metabólico. Este estudio se encaminó a determinar la concentración plasmática de aminoácidos en pacientes con neuropatía epidémica diagnósticados en Cuba. Se encontró que la concentración plasmática de aminoácidos azufrados no cambió respecto al grupo control, por lo que creemos que el factor tóxico tenga un papel primordial. Sin embargo, se encontraron variaciones importantes en un grupo de aminoácidos que pensamos pueda deberse a cambios metabólicos de carácter nutricional que generalmente acompañan a esta enfermedad.

Aminoácidos plasmáticos en pacientes con neuropatía epidémica diagnósticados en Cuba / Plams amino acids in patients to whom epidemic neuropathy was diagnosed in Cuba

En los últimos años los estudios en pacientes con neuropatías han reveladocambios bioquímicos importantes que han explicado la pérdida de la visión por lesiones del nervio óptico con desmielización al nivel de la zona axial del nervio y en la cual los aminoácidos azufrados desempeñan un importante papel metabólico. Este estudio se encaminó a determinar la concentración plasmática de aminoácidos en pacientes con neuropatía epidémica diagnósticados en Cuba. Se encontró que la concentración plasmática de aminoácidos azufrados no cambió respecto al grupo control, por lo que creemos que el factor tóxico tenga un papel primordial. Sin embargo, se encontraron variaciones importantes en un grupo de aminoácidos que pensamos pueda deberse a cambios metabólicos de carácter nutricional que generalmente acpmpañan a esta enfermedad

Nutritional studies on Paracoccidioides brasiliensis: the role of organic sulfur in dimorphism.

The nutritional requirements of the mycelial and yeast-like phases of the dimorphic fungus Paracoccidioides brasiliensis, a human pathogen, were investigated. For all nine isolates tested, mycelial cells were prototrophic, whereas yeast-like cells required a sulfur-containing amino acid for growth. Moreover, changing the source of nitrogen greatly affected the morphology of the yeast-like cells.

Free amino acids in liver of patients with homocystinuria due to cystathionine synthase deficiency: effects of vitamin B6.

Patients with homocystinuria due to cystathionine synthase deficiency do not have free homocystine in the liver when it is present in high concentrations in the plasma and the urine. The liver of these patients is capable of maintaining normal concentrations of cystine at a time when the plasma cystine concentration is severely reduced. There is an increase in the methionine concentration of the liver which is reduced to normal concentrations during pyridoxine therapy.

Milk protein quantity and quality in low-birth-weight infants. III. Effects on sulfur amino acids in plasma and urine.

Well, appropriate-for-gestational age, low-birth-weight infants weighing 2,100 gm or less were divided into three gestational age groups and assigned randomly within each age group to one of five feeding regimens: pooled human milk; formula 1 (F1) = 1.5gm/dl protein, 60 parts bovine whey proteins: 40 parts bovine caseins; F2 = 3.0 gm/dl, 60:40; F3 = 1.5 gm/dl, 18:82; F4=3.0 gm/dl, 18:82. Plasma and urine concentrations of methionine and of cystathionine were higher in the infants fed F1 to F4 than in the infants fed BM. The plasma cystine concentrations of infants fed F2 (which had a cystine content at least twice that of any of the other formulas) were significantly higher than those of infants fed BM. Plasma taurine concentrations of infants fed F1 or F4, which were virtually devoid of taurine, decreased steadily during the course of study becoming lower than those of infants fed BM. Urine taurine concentrations of infants fed F1, F3, or F4 (but not F2 which had more taurine than F1, F3, or F4) were lower than those of infants fed BM. These results provide further evidence for the limited capacity of the preterm human infant to convert methionine to cystine, owing to delayed maturation of cytathionase, and suggest a limited capacity to convert cystine to taurine. The latter suggestion is consistent with low human hepatic cysteinesulfinic acid decarboxylase activity 0.26 (fetal) and 0.32 (adult) nmoles/mg protein/hour vs 468 in rat liver.