The impact of digestible lysine and sulfur amino acids on eggshell quality and egg weight control in old ISA brown hens during 62 to 74 wk

Modifying dietary amino acids has been proposed as a strategy to improve eggshell quality by slowing down increases in egg weight (EW). This study aimed to investigate the effects of different levels of digestible lysine (dLYS) and ratios of digestible sulfur amino acids (dTSAA) to dLYS on performance and eggshell quality in ISA brown hens. A total of 288 hens were individually housed and assigned to 8 treatments, which combined 2 levels of dLYS (5.9 and 5.5 g/kg) with 4 ratios of dTSAA:dLYS (90, 85, 80, and 75) in a factorial arrangement. The study lasted 12 wk, starting at 62 wk of age. The number of eggs was not affected by the interaction between dLYS and dTSAA:dLYS or their main effect. However, the interaction between dLYS and dTSAA:dLYS showed that reducing the dTSAA:dLYS ratio from 85 to 75 when hens were fed 5.5 g/kg of dLYS resulted in a lower EW. Conversely, when hens were fed 5.9 g/kg of dLYS, no significant difference was found in EW among the different ratios of dTSAA:dLYS. Although there was no interaction between the levels of dLYS and dTSAA:dLYS on eggshell quality, reducing the dLYS level from 5.9 to 5.5 slowed down the deterioration in eggshell-breaking strength and eggshell thickness, regardless of the dTSAA:dLYS ratio. These findings suggest that adjusting dietary dLYS while maintaining the dTSAA:dLYS ratio of no less than 85 may be an effective strategy for decelerating the deterioration of eggshell quality in laying hen operations without impacting the egg production rate.

The effects of total sulfur amino acids on the intestinal health status of broilers challenged with Eimeria spp

This study evaluated the effects of total sulfur amino acid (TSAA) levels on the performance and intestinal health of broilers challenged with Eimeria spp. A total of 432 one-day-old off-sex Cobb 500 male chicks were randomly assigned to a 3 × 2 factorial arrangement (6 replicates/12 birds), with diets and Eimeria challenge as the main factors. The diets were as follows: 70% (no methionine [Met] supplementation), 85, and 100% TSAA, supplemented with L-Met. At day 14, the challenged birds (n = 216) were orally gavaged with a pool of Eimeria acervulina, Eimeria maxima, and Eimeria tenella sporulated oocysts, and the unchallenged birds (n = 216) received water. At 6 and 12 D post inoculation (dpi), performance and intestinal health were evaluated. The challenge, regardless of diets, significantly impaired the performance, intestinal villi height, villus-to-crypt ratio, and ileal digestibility of dry matter, energy, and crude protein (CP) and modulated the tight junction protein (TJP) expression throughout the experiment. Moreover, the superoxide dismutase activity was increased, whereas the reduced glutathione (GSH)-to-oxidized glutathione (GSSG) ratio was decreased by the challenge at 6 dpi. Regardless of the challenge, the 70% TSAA diet reduced the body weight and feed intake in all phases, whereas the ileal digestibility of CP was higher in birds fed with the 70% TSAA diet than in those fed with the 100% TSAA diet at 6 dpi. No major differences were observed among the diets with regard to the intestinal histomorphology and TJP expression, and birds fed with the 100% TSAA diet had the highest GSH concentration at 12 dpi. Few interactions were observed, and the Met supplementation counteracted the negative effects of the Eimeria challenge on GSH concentration when 85 and 100% of TSAA levels were reached. Overall, the Eimeria challenge had a negative impact on growth and intestinal health. Moreover, the supplementation of L-Met until either 85 or 100% of TSAA levels were reached was enough to assure good performance and intestinal health in birds challenged or not challenged with Eimeria spp.

In vitro inhibition of Saccharomyces cerevisiae growth by Metschnikowia spp. triggered by fast removal of iron via two ways

Simple and convenient innovative assays in vitro demonstrating Metschnikowia spp. competition with Saccharomyces cerevisiae for an essential nutrient iron are presented. The tested Metschnikowia strains possess a common genetically determined property of secreting a pulcherriminic acid which in the presence of iron (III) ions forms an insoluble red pigment pulcherrimin. Both initial accumulation in growing Metschnikowia cells and subsequent precipitation in the form of pulcherrimin in the media contribute to iron removal by functioning cells. The predominant way depends on the strain. Due to fast elimination of iron, the growth of S. cerevisiae can be inhibited by tested Metschnikowia strains at concentrations of elemental iron in the media not exceeding 12 mg kg^-1. Inhibition can be regulated by additional supply of microquantities of iron onto the surface of the solid medium within 20-24 h. At relatively low concentrations of elemental iron (below 1 mg kg^-1), additional supplements of iron onto the surface provide an advancement in understanding the inhibition possibilities and enable the assay control. Microscopy observations revealed that Metschnikowia chlamydospores are involved in iron removal at relatively high iron concentrations. The results may find application in development of new methodologies and strategies for biocontrol or inhibition of pathogenic microorganisms.

Cassane Diterpenoids from the Aerial Parts of Caesalpinia pulcherrima and Their Antifeedant and Insecticidal Activities against Mythimna separate and Plutella xylostella

Ten new cassane diterpenoids, caesalpulcherrins A-J (1-10), together with 11 known analogues (11-21) were isolated from the aerial parts of Caesalpinia pulcherrima. Their structures and relative stereochemistry were elucidated by spectrometric and spectroscopic methods, including one-dimensional (1D) and two-dimensional (2D) NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and single-crystal X-ray diffraction analysis. Compounds 1-4 represent the first examples of 2,5-dimethoxyfuranocassane diterpenoids. Results of the antifeedant activity indicated that isovouacapenol C (12) and pulcherrin N (14) exhibited remarkable antifeedant activity against Mythimna separate with EC₅₀ values of 3.43 and 4.20 μg/cm², respectively. Meanwhile, pulcherrimin C (13) and 12-demethyl neocaesalpin F (18) exerted significant antifeedant activity against Plutella xylostella with an EC₅₀ data of 4.00 and 3.05 μg/cm², respectively. Some of the compounds showed obvious toxic activity against the plant-feeding generalist insect herbivores, M. separate and P. xylostella, at 0.8 mg/mL (800 ppm). Furthermore, the structure-activity relationships of antifeedant and insecticidal activities are also discussed in the article.

Lanthionine ketimine-5-ethyl ester provides neuroprotection in a zebrafish model of okadaic acid-induced Alzheimer's disease

Okadaic acid (OKA) is a protein phosphatase 2A inhibitor that is used to induce neurodegeneration and study disease states such as Alzheimer's disease (AD). Lanthionine ketimine-5-ethyl ester (LKE) is a bioavailable derivative of the naturally occurring brain sulfur metabolite, lanthionine ketimine (LK). In previously conducted studies, LKE exhibited neuroprotective and neurotrophic properties in murine models but its mechanism of action remains to be clarified. In this study, a recently established zebrafish OKA-induced AD model was utilized to further elucidate the neuroprotective and neurotrophic properties of LKE in the context of an AD-like condition. The fish were divided into 3 groups containing 8 fish per group. Group #1 = negative control, Group #2 = 100 nM OKA, Group #3 = 100 nM OKA +500 μM LKE. OKA caused severe cognitive impairments in the zebrafish, but concomitant treatment with LKE protected against cognitive impairments. Further, LKE significantly and substantially reduced the number of apoptotic brain cells, increased brain-derived neurotrophic factor (BDNF), and increased phospho-activation of the pro-survival factors pAkt (Ser 473) and pCREB (Ser133). These findings clarify the neuroprotective and neurotrophic effects of LKE by highlighting particular survival pathways that are bolstered by the experimental therapeutic LKE.

Neuroprotective and neurotrophic effects of Lanthionine Ketimine Ester

Lanthionine ketimine ethyl ester (LKE) is a synthetic derivative of the naturally occurring amino acid lanthionine ketimine. We previously showed that LKE reduced clinical signs in a mouse model of multiple sclerosis (MS) associated with reductions in axonal damage; however, whether LKE has direct beneficial actions on mammalian neuronal cells was not examined. In the current study, we tested the effects of LKE in SH-SY5Y human neuronal cells and in primary mouse cerebellar granule neurons. In both cell types, LKE dose-dependently reduced the cell death that occurred spontaneously followed a change in media. LKE also reduced cell death due to glutamate excitoxicity, accompanied by a reduction in production of reactive oxygen species. LKE induced neuritogenesis in both undifferentiated SH-SY5Y cells and in primary neuron, increasing process numbers and lengths. These results demonstrate that direct neuroprotective and neurotrophic effects of LKE likely contribute to its beneficial actions in vivo.

Role of sulfur containing amino acids as an adjuvant therapy in the prevention of diabetes and its associated complications

Amino acid supplementation is gaining acceptance as an important adjuvant therapy in the treatment of diabetes and its associated complications. Numerous studies in the literature report the impaired amino acid metabolism in diabetes and the beneficial effects of amino acids are positively correlated with the increase in plasma levels of those amino acids. Oxidative stress is known to play a major role in diabetic pathophysiology. Sulfur containing compounds are well known in the treatment of oxidative stress induced pathological disorders. Methionine, cysteine, and homocysteine are the three common sulfur containing amino acids. In addition, taurine, a sulfonic acid containing an amino group (amino sulfonic acid), is found in substantial amounts in mammalian tissues. Both experimental and clinical studies reported the modulatory effects of cysteine, N-acetyl cysteine, or compounds having cysteine moiety in the regulation of insulin secretion and plasma glucose levels. Taurine supplementation has been found to prevent the onset of diabetes mellitus in experimental models of both insulin dependent and insulin independent pathways. Recent reports suggest that the beneficial role of cysteine or taurine is mediated via their ability in reducing glycooxidation and preventing the generation of intracellular reactive intermediates. Studies with methionine or S-adinosyl methionine has been shown to increase mitochondrial DNA density in skeletal muscle, improve insulin sensitivity and prevent body weight gain. Homocysteine, on the other hand, is an emerging risk factor for cardiovascular disease and diabetic patients have higher levels of this sulfur containing amino acid. Supplementation with cysteine or taurine, however, was found to be effective in reducing plasma homocysteine levels. This review will discuss the role of sulfur containing amino acids in the regulation of hyperglycemia and in the development of its associated pathological dysfunctions.

Proteomic identification of binding partners for the brain metabolite lanthionine ketimine (LK) and documentation of LK effects on microglia and motoneuron cell cultures

Lanthionine ketimine (LK) represents a poorly understood class of thioethers present in mammalian CNS. Previous work has indicated high-affinity interaction of LK with synaptosomal membrane protein(s), but neither LK binding partners nor specific bioactivities have been reported. In this study, LK was chemically synthesized and used as an affinity agent to capture binding partners from mammalian brain lysate. Liquid chromatography with electrospray ionization-mass spectrometry of electrophoretically separated, LK-bound proteins identified polypeptides implicated in axon remodeling or vesicle trafficking and diseases including Alzheimer's disease and schizophrenia: collapsin response mediator protein-2/dihydropyrimidinase-like protein-2 (CRMP2/DRP2/DPYSL2), myelin basic protein, and syntaxin-binding protein-1 (STXBP1/Munc-18). Also identified was the recently discovered glutathione-binding protein lanthionine synthetase-like protein-1. Functional consequences of LK:CRMP2 interactions were probed through immunoprecipitation studies using brain lysate wherein LK was found to increase CRMP2 coprecipitation with its partner neurofibromin-1 but decreased CRMP2 coprecipitation with beta-tubulin. Functional studies of NSC-34 motor neuron-like cells indicated that a cell-permeable LK-ester, LKE, was nontoxic and protective against oxidative challenge with H(2)O(2). LKE-treated NSC-34 cells significantly increased neurite number and length in a serum concentration-dependent manner, consistent with a CRMP2 interaction. Finally, LKE antagonized the activation of EOC-20 microglia by inflammogens. The results are discussed with reference to possible biochemical origins, paracrine functions, neurological significance, and pharmacological potential of lanthionyl compounds.

The interactive effects of glycine, total sulfur amino acids, and lysine supplementation to corn-soybean meal diets on growth performance and serum uric acid and urea concentrations in broilers

Four experiments were conducted to determine the interactive effects of Gly, TSAA, and Lys in corn-soybean meal diets on growth performance of broilers. All experiments were conducted with female Ross x Ross 308 or 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 5 to 8 replications with 5 or 6 broilers per replicate pen. Diets in all experiments were fed without or with Gly (2.32% total Gly + Ser). All diets contained 0.25% l-Lys.HCl except in experiment 1, where no crystalline Lys was added. In experiment 1, the total dietary Lys level was 1.26% with TSAA:Lys of 0.72 and 0.76. Increasing TSAA:Lys increased (P < 0.07) G:F. The main effect of Gly was not significant for ADG, ADFI, or G:F; however, G:F was increased by Gly in broilers fed 0.72 but not in those fed 0.76 TSAA:Lys (Gly x TSAA:Lys, P < 0.03). In experiment 2, the total dietary Lys level was 1.26% with TSAA:Lys of 0.51, 0.68, 0.72, and 0.76. Glycine addition did not affect ADG, ADFI, or G:F; however, increasing TSAA:Lys linearly increased (P < 0.01) ADG, ADFI, and G:F and the response was quadratic for ADG and G:F. Experiment 3 was similar to experiment 2 except the total dietary Lys level was 1.35%. Glycine addition increased (P < 0.03) G:F and decreased (P < 0.04) serum uric acid (SUA) and serum urea N concentrations. Also, increasing TSAA:Lys linearly and quadratically (P < 0.02) increased ADG, ADFI, and G:F. In experiment 4, broilers were fed 2 levels of total dietary Lys (1.26 and 1.35%), 3 levels of TSAA:Lys (0.72, 0.76, and 0.80), and without or with Gly supplementation up to a total of 2.32% Gly + Ser. Glycine addition increased ADG (P < 0.02) and G:F (P < 0.01). The increase in G:F with Gly was not the same for all TSAA:Lys (Gly x TSAA:Lys, P < 0.07). Increasing Lys increased (P < 0.01 to 0.10) ADG, ADFI, and G:F. Glycine addition increased ADG and ADFI more in broilers fed 1.35% Lys than in those fed 1.26% Lys (Lys x Gly, P < 0.09). Glycine addition increased SUA in broilers fed 1.26% Lys but decreased SUA in broilers fed 1.35% Lys (P < 0.01). Glycine addition decreased SUA in broilers fed the TSAA:Lys of 0.80 but not at the other TSAA:Lys (P < 0.08). These data indicate that Gly increased G:F and decreased SUA in diets with 1.35% Lys and excess TSAA.

The novel gaseous vasorelaxant hydrogen sulfide inhibits angiotensin-converting enzyme activity of endothelial cells

OBJECTIVE

Beside NO (nitric monoxide) and CO (carbon monoxide), H2S (hydrogen sulfide) has been identified recently as the third gasotransmitter. By acting directly on KATP-channels on smooth muscle cells (SMC) H2S possesses vasorelaxing properties. It has the potential to react with metal ions (i.e. Cu, Fe, Zn) in metalloproteins. Angiotensin-converting enzyme (ACE), responsible for vasoconstriction, is a zinc (Zn) containing enzyme. We therefore hypothesized that H2S may interact with the Zn in the active center of ACE, modulating (inhibiting) enzyme activity.

METHODS

ACE activity was measured on the surface of human endothelial cells (HUVECs) monolayers in culture, ex-vivo in umbilical veins and in HUVEC protein extracts. Quantitative real-time polymerase chain reaction (PCR) was used to study the effect of H2S on ACE mRNA expression in HUVECs.

RESULTS

H2S inhibited the activity of ACE in HUVEC protein extracts in a dose-dependent manner, and only Zn but not Cd, Ca or Mg could counteract the inhibitory effect. Cell-surface ACE activity was inhibited by H2S on HUVEC monolayers and in ex-vivo umbilical veins. No influence of H2S on ACE mRNA expression was observed.

CONCLUSION

H2S exhibits direct inhibitory action on ACE activity in HUVECs, obviously by interfering with the Zn in the active center of the enzyme. Thus, beside the known influence of H2S on SMC KATP-channels, the observed direct ACE inhibitory effect may add to the vasorelaxant effect of H2S in the vasculature by reducing angiotensin II production and inhibiting bradykinin degradation.

An inhibitor of human asparagine synthetase suppresses proliferation of an L-asparaginase-resistant leukemia cell line

Drug resistance in lymphoblastic and myeloblastic leukemia cells is poorly understood, with several lines of evidence suggesting that resistance can be correlated with upregulation of human asparagine synthetase (hASNS) expression, although this hypothesis is controversial. New tools are needed to investigate this clinically important question, including potent hASNS inhibitors. In vitro experiments show an adenylated sulfoximine to be a slow-onset, tight-binding inhibitor of hASNS with nanomolar affinity. This binding affinity represents a 10-fold improvement over that reported for the only other well-characterized hASNS inhibitor. The adenylated sulfoximine has a cytostatic effect on L-asparaginase-resistant MOLT-4 cells cultured in the presence of L-asparaginase, an enzyme that depletes L-asparagine in the growth medium. These observations represent direct evidence that potent hASNS inhibitors may prove to be effective agents for the clinical treatment of acute lymphoblastic leukemia.

[The effect of arginine and its metabolites on tissue culture of rat myocardium]

In was demonstrated using the method of organotypic culture that arginine and its metabolites: cutrulline, ornitine and especially urea, in ultralow doses stimulated the myocardium proliferation in mature rats. Only nitric oxide (NO) possessed the antiproliferative effect. The cytrulline effect was similar to the arginine effect. The metabolism of these amino acids is intimately interrelated so the cytrulline can be used in the clinic practice as an "argininepreserved" preparation. The antiproliferative NO effect can be delayed by thiole-containing preparations: glulathione and unithiole.

Variations in the digestible sulfur amino acid requirement of broiler chickens due to sex, growth criteria, rearing environment, and processing yield characteristics

Four experiments (Exp.) were conducted with Cobb 500 chicks to evaluate variations in the estimated digestible sulfur amino acid (DSAA) requirement of broilers due to rearing environment, sex, or growth performance during the starter period (7 to 19 d), and live performance response and carcass yield characteristics during the grower period (21 to 42 d). In the first 3 experiments conducted during the starter period, chicks were allocated to battery or floor pens, and in the fourth experiment birds were reared in floor pens. For Exp. 1, 2, and 3 a sulfur amino acid deficient corn-soybean meal-corn gluten meal basal diet and for the grower experiment a corn-soybean meal-peanut meal basal diet was formulated to be isocaloric and isonitrogenous within experiment. Graded levels of DSAA ranged from 0.54 to 0.94% in Exp. 1, 0.53 to 1.03% in Exp. 2, 0.49 to 0.89% in Exp. 3, and 0.43 to 0.83% in Exp. 4. True digestibility of the diets was determined using the precision-fed rooster assay. The DSAA requirements were estimated using 1-slope broken-line methodology. During the starter period, the average DSAA requirement of males and females was similar when based on the gain to feed ratio (G:F; 0.71 and 0.71%, respectively) and BW gain (BWG; 0.67 and 0.67%, respectively). In Exp. 3 involving battery and floor pens, males and females had similar DSAA requirement estimates, but the DSAA requirement based on maximal G:F (0.68%) was higher than the maximal BWG requirement (0.61%). In the grower period, the estimated DSAA requirement for males based on G:F was higher than that based on BWG, but the BWG and G:F requirements were similar for females. The DSAA requirement estimates were similar for males and females based on BWG (0.55%), but the DSAA requirement based on G:F was higher for males than females. The DSAA requirement for maximum breast meat yield was similar for males (0.55%) and females (0.56%), and the requirement for maximal breast meat yield was similar to that for maximal BWG. The DSAA requirements were similar based on sex, rearing environment, or both; however, there was a difference in the estimated DSAA requirements between growth and carcass responses.

The Effect of Dietary Protein Level and Total Sulfur Amino Acid:Lysine Ratio on Egg Production Parameters and Egg Yield in Hy-Line W-98 Hens

A 3 x 3 treatment arrangement varying in dietary protein and TSAA:Lys was used to evaluate the effect of low-protein diets fed to Hy-Line W-98 laying hens. Phase I was 20 to 43 wk of age with 18.9, 17.0, and 14.4 g of protein/hen per day and 0.97, 0.85, and 0.82 TSAA:Lys, whereas phase II was 44 to 63 wk of age with 16.3, 14.6, and 13.8 g of protein/hen per day and 0.92, 0.82, and 0.72 TSAA:Lys. Egg production and feed consumption decreased from 83.7 to 82.2% and 98.8 to 95.6 g, respectively. Feed efficiency improved from 1.680 to 1.645 g of feed/g of egg mass with decreasing dietary protein. Body weight gain was similar for hens fed high or medium protein diets. In phase II, hens consuming 13.8 g of protein/day had significantly reduced egg weight compared with hens consuming 14.6 or 16.3 g of protein/day. Wet and dry albumen percentage, albumen solids, and albumen and yolk protein percentages were significantly decreased with feeding low-protein diets. Yolk protein percentage was increased from 14.85 to 15.11% when decreasing the ratio from 0.97 to 0.82. Hens consuming a low-protein diet produced eggs with the lowest specific gravity. An interaction was observed for protein retention during phase I, feeding 14.4 g of protein/day or a ratio of 0.97 improved protein retention by 9 and 16%, respectively. Overall, hens consuming 16.3 or 14.6 g of protein/hen per day performed similar to hens consuming 18.9 and 17.0 g of protein/hen per day during P1 and P2, respectively. Also, hens consuming diets containing 0.97 and 0.92 TSAA:Lys produced eggs with improved shell quality as compared with other ratios during P1 and P2, respectively.

Effect of amino acids containing sulfur on dithiolopyrrolone antibiotic productions by Saccharothrix algeriensis NRRL B-24137

AIMS

To study the effect of sulfur-containing amino acids (L-cysteine, L-cystine, L-methionine and DL-ethionine) on the production of dithiolopyrrolone antibiotics by Saccharothrix algeriensis NRRL B-24137.

METHODS AND RESULTS

The production levels of dithiolopyrrolones were investigated by using high performance liquid chromatography in a chemically semi-synthetic medium. The production of the studied antibiotics depends upon the nature, concentration and the time of addition of these sources in the culture medium. Both cysteine and cystine favoured the specific productions of dithiolopyrrolones; iso-butyryl-pyrrothine (ISP) by cysteine, however butanoyl-pyrrothine, senecioyl-pyrrothine and tigloyl-pyrrothine by cystine, when added initially to the culture medium. The maximum specific productions of dithiolopyrrolones were observed in the presence of 5 mmol l(-1) cystine for thiolutin, 5 mmol l(-1) cysteine for ISP, and 10 mmol l(-1) cystine for others studied dithiolopyrrolones as shown in Fig. 3. The production of these antibiotics was decreased when the concentrations of cysteine and cystine were in excess. All dithiolopyrrolone specific productions were strongly inhibited by addition of methionine and ethionine, without inhibition of mycelial growth.

CONCLUSIONS

Among all studied amino acids, cystine and cysteine can be used as supplements for improvement the production of dithiolopyrrolone antibiotics by S. algeriensis NRRL B-24137.

SIGNIFICANCE AND IMPACT OF THE STUDY

Dithiolopyrrolone antibiotics have many important applications for employing them as medicaments, particularly in the treatment of human and animal cancers. In the present work, the influence of containing-sulfur amino acids on dithiolopyrrolone antibiotic productions was studied. The obtained results can be employed for the optimization of the culture medium for the dithiolopyrrolone productions in higher quantities.

Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs1,2

Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P < 0.05) and improved G:F (linear; P < 0.002). The pooled data of Exp. 1 (SAA study) and Exp. 2 indicated that increasing TID SAA from 0.63 to 0.90% increased ADG (quadratic; P < 0.01) and improved G:F (quadratic; P < 0.01). Various methods of analyzing the growth response surface indicated that the optimal TID Lys concentration ranged from 1.28 to 1.32% for ADG (Exp. 1), and the optimal TID SAA concentration ranged from 0.73 to 0.77% for ADG and 0.80 to 0.83% for G:F (pooled Exp. 1 and 2), respectively. In Exp. 3, increasing TID SAA concentrations from 0.50 to 0.68% resulted in a linear improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity.

Different effects of sulfur amino acids on prolidase and prolinase activity in normal and prolidase-deficient human erythrocytes

BACKGROUND

Prolidase and prolinase activity is known to be enhanced significantly in some diseases. Recently, the effect of amino acids on prolidase and prolinase activity in normal and prolidase-deficient human erythrocytes was investigated. It was reported that both enzymes were enhanced by glycine and alanine in the presence of MnCl(2).

METHODS

Erythrocytes were isolated from heparinized blood from normal human and a patient with prolidase deficiency. Effects of various sulfur amino acids on prolidase and prolinase activities against iminodipeptides in the presence of 1 or 0.1 mmol/l MnCl(2) were investigated.

RESULTS

Prolinase activity against prolylglycine in normal and prolidase-deficient erythrocyte lysates was inhibited by L-methionine, NAc-L-methionine and D,L-methionine in a concentration-dependent manner, but D-methionine enhanced the activity in low concentrations (0-20 mmol/l). D,L-Homocysteine inhibited the activity more strongly than other sulfur amino acids tested in a concentration-dependent manner. On the other hand, prolidase activity against glycylproline was enhanced by L-methionine, D-methionine, D,L-methionine, D,L-homocysteine thiolactone and D,L-ethionine. The rates of enhancement by these sulfur amino acids were in the following order: D,L-ethionine>D,L-methionine, D-methionine, D,L-homocysteine thiolactone>L-methionine (10 mmol/l).

CONCLUSION

The prolinase activity in normal and prolidase-deficient erythrocyte lysates was inhibited by L-methionine, D,L-ethionine and D,L-homocysteine. On the other hand, prolidase activity in their erythrocyte lysates was enhanced by D,L-ethionine, D-methionine and L-methionine. These results indicate the effects of these sulfur amino acids on prolidase and prolinase activities were different.

Functions of sulfur-containing amino acids in lipid metabolism

It is known that plasma lipid levels are controlled not only by dietary fat and carbohydrate but also by dietary protein and amino acids. Although it used to be thought that the source of protein was important, it is known that amino acid composition, amino acids themselves, and peptides from digested protein are more important than the protein source. Sulfur-containing amino acids (SAAs) are recognized to be some of the most potent modulators of lipid metabolism among amino acids. It has been demonstrated that SAAs have an increasing effect on HDL (high-density lipoprotein)-cholesterol and a decreasing effect on VLDL (very low-density lipoprotein)-cholesterol. These data lead us to propose that SAAs have some beneficial functions against atherosclerotic diseases and metabolic syndrome. Relative availability of SAAs (RASAA) as well as the amount of SAAs in dietary protein would determine lipid metabolism. Therefore, we propose RASAA as a feasible index for improvement of lipid metabolism by amino acids. Although it is not clear how SAAs influence gene expression and lipid metabolism at a molecular level, SAAs change the metabolic pathway through transcriptional stimulation and posttranslational modification of regulatory proteins.

Sulfur amino acid restriction induces the pi class of glutathione S-transferase expression in primary rat hepatocytes

The regulation of genes by amino acids is attracting increasing attention. In the present study, we investigated the restriction of expression of the pi class of glutathione S-transferase (GST Yp) by sulfur amino acids. Hepatocytes isolated from male Sprague-Dawley rats were cultured with L-15-based medium containing low (LSAA; 0.1 mmol/L L-methionine and 0.1 mmol/L L-cysteine) or high (HSAA; 0.5 mmol/L L-methionine and 0.2 mmol/L L-cysteine) amounts of sulfur amino acids for up to 6 d. Cellular protein contents did not differ between LSAA- and HSAA-treated cells over the entire period. In contrast, glutathione concentrations were suppressed by the LSAA medium and on d 6 were only 20% of those of HSAA-treated cells (P < 0.05). As shown by immunoblot analysis, GST Yp protein levels were greater in LSAA-treated cells than in HSAA-treated cells (P < 0.05). The induction of GST Yp by L-methionine and L-cysteine restriction was not affected by insulin and dexamethasone, but the latter suppressed GST Yp expression (P < 0.05). LSAA increased GST Yp mRNA levels and GST activity toward ethacrynic acid (P < 0.05). GST Yp induction occurred only in cells with a limited supply of L-methionine; restriction of L-isoleucine, L-leucine, L-lysine, and L-phenylalanine had no significant effect. In contrast with the induction of GST Yp, the expression of the GST isoforms Ya and Yb was not changed by amino acid restriction. In conclusion, hepatic GST Yp gene expression is upregulated by a limited availability of sulfur amino acids.

Effect of sulfur amino acids on stimulus-induced superoxide generation and translocation of p47phox and p67phox to cell membrane in human neutrophils and the scavenging of free radical

BACKGROUND

Various cystathionine metabolites are in the urine of the patients with cystathioninuria. Among these metabolites, cystathionine ketimine significantly enhanced N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide generation in parallel with tyrosyl phosphorylation of 45 kDa protein in human neutrophils.

METHODS

We investigated the effect of various sulfur amino acids on fMLP-, phorbol-12-myristate-13-acetate (PMA)- and arachidonic acid (AA)-induced superoxide generation in human neutrophils. In addition, the effects of these sulfur amino acids on the membrane translocation of cytosolic compounds p47(phox) and p67(phox) and on the scavenging of superoxide anions were investigated.

RESULTS

When the cells were preincubated with various sulfur amino acids, fMLP-induced superoxide generation was enhanced by D,L-homocysteine and D,L-homocysteine-thiolactone but was inhibited by other sulfur amino acids in a concentration-dependent manner. The AA-induced superoxide was enhanced by L-cysteine, N-acetyl-L-cysteine and D,L-homocysteine. The strength of enhancing effect was: L-cysteine>>N-acetyl-L-cysteine>D,L-homocysteine. On the other hand, the superoxide generation was weakly inhibited by L-cystathionine. The superoxide generation induced by PMA was weakly inhibited by L-cysteine, N-acetyl-L-cysteine and L-cystathionine. Homocysteine and D,L-homocysteine-thiolactone had no effect. In addition, D,L-homocysteine also enhanced translocation to the cell membrane of cytosolic compounds p47(phox) and p67(phox). Conversely, L-cystathionine and N-acetyl-L-cysteine inhibited the translocation to membrane of p47(phox) and p67(phox) in a concentration-dependent manner. N-acetyl-L-cysteine and L-cysteine revealed scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The sulfur amino acids tested also indicated radical scavenging activity on superoxide anion generated by phenazine methoxysulfate (PMS)-NADH system.

CONCLUSION

D,L-homocysteine and D,L-homocysteine-thiolactone enhanced fMLP-induced superoxide generation by the increment of translocation to membrane of p47(phox) and p67(phox). L-cystathionine and N-acetyl-L-cysteine suppressed fMLP- and PMA-induced superoxide generation by the inhibition of translocation to membrane of p47(phox) and p67(phox). N-acetyl-L-cysteine also had scavenging activity against DPPH radicals and superoxide anion.

Antioxidant effects of sulfur-containing amino acids

Sulfur is an essential element for the entire biological kingdom because of its incorporation into amino acids, proteins and other biomolecules. Sulfur atoms are also important in the iron-containing flavoenzymes. Unlike humans, plants can use inorganic sulfur to synthesize sulfur-containing amino acids. Therefore, plants are an important source of sulfur for humans. Sulfur-containing compounds are found in all body cells and are indispensable for life. Some of sulfur-containing antioxidant compounds are, cysteine, methionine, taurine, glutathione, lipoic acid, mercaptopropionylglycine, N-acetylcysteine, and the three major organosulfur compounds of garlic oil, diallylsulfide, diallyldisulfide and diallyltrisulfide. In a comparison of the structure-function relationship among these sulfur-containing antioxidant compounds, dihydrolipoic acid (the reduced form of LA) is the most effective antioxidant. Dihydrolipoic acid contains two sulfhydryl groups and can undergo further oxidation reaction to form lipoic acid. The antioxidative activities of sulfur-containing compounds follow a general trend, the more highly reduced forms are stronger antioxidants and the number of sulfur atoms determine, at least in part, their modulatory activites on the glutathione related antioxidant enzymes. In this article, the antioxidant effects and the antioxidative activities, of sulfur-containing amino acids, are reviewed. In addition, the general antioxidant effects and the structure-function relationship of some sulfur-containing compounds are also reviewed.

The effect of graded levels of dietary casein, with or without methionine supplementation, on glutathione concentration in unstressed and endotoxin-treated rats

Glutathione (GSH) concentration was measured in rats fed either graded levels of dietary casein (experiment 1; 180 g, 120 g, 80 g, or 60 g protein/kg diet) or graded levels of dietary casein, supplemented with methionine to equalize dietary sulfur amino acid content to that seen in an 180 g/kg casein diet supplemented with 0.3 g L-methionine/kg diet (experiment 2; 180 g protein +0.3 g L-methionine, 80 g protein +6.70 g L-methionine, or 60 g protein +7.45 g L-methionine/kg diet). Rats were given an inflammatory challenge by intraperitoneal injection of endotoxin (lipopolysaccharide from Escherichia coli), and were compared with ad libitum and pair-fed controls. Glutathione concentration in various organs (liver, lung, spleen, and thymus) decreased in animals fed the low-protein diets (80 g or 60 g/kg diet). Addition of the sulfur amino acid, methionine, to the low-protein diets restored glutathione concentrations in animals fed ad libitum and prevented the fall in GSH concentration, which occurred in lung, spleen, and thymus in response to the endotoxin. Despite the similarity in the amount of sulfur amino acid consumed between the groups fed the 180 g protein +0.3 g L-methionine and the 60 g protein +7.45 g L-methionine/kg diet, in experiment 2, hepatic GSH concentration significantly increased in the latter group, in animals fed ad libitum and in the endotoxin-treated animals, but not in the pair-fed controls.

Sulfur-containing amino acids attenuate the development of liver fibrosis in rats through down-regulation of stellate cell activation

BACKGROUND/AIMS

We tested the pharmacological action of sulfur-containing amino acids on the development of liver fibrosis in rats and on the function of cultured stellate cells.

METHODS

Liver fibrosis was induced in rats by thioacetamide administration or by ligating the common bile duct. DNA synthesis of cultured stellate cells was evaluated by BrdU incorporation. The expression of proteins and phospho-proteins was determined by western blot analysis. mRNA expression was evaluated by RT-PCR.

RESULTS

Oral administration of l-cysteine or l-methionine attenuated the deposition of collagen in liver tissues in the two fibrotic models, accompanying a reduction in the expression of smooth muscle alpha-actin and platelet-derived growth factor receptor beta and mRNAs of collagens, transforming growth factor-betas and tissue inhibitors of matrix metalloproteinase. In cultured stellate cells, l-cysteine and l-methionine suppressed the DNA synthesis and the expression of growth factor receptors, smooth muscle alpha-actin and type I collagen. They hampered the phosphorylation of p44/42 MAPK and Akt under platelet-derived growth factor-BB stimulation. Stellate cells were found to express methionine adenosyltransferase 2A.

CONCLUSIONS

l-Cysteine and l-methionine regulate the activation of stellate cells. Their oral supply aids the suppression of the progression of liver fibrosis.

The balance of dietary sulfur amino acids and the route of feeding affect plasma homocysteine concentrations in neonatal piglets

Plasma total homocysteine (tHcy) concentrations are associated with atherogenesis in adults and increased risk of stroke in infants and children. After a series of experiments to compare the methionine (Met) requirement and cysteine (Cys)-sparing capacity in piglets that were parenterally or enterally fed, we examined the effects of route of feeding and dietary Cys on plasma tHcy concentrations. Piglets (n = 60; 6-8 d old) were fed elemental diets, intragastrically (n = 28) or intravenously (n = 32), with 0.55 g. kg(-1). d(-1) dietary Cys (n = 28) or without dietary Cys (n = 32). Dietary Met ranged from deficient to excess. Increasing Met intake increased (P < 0.01) plasma tHcy in all treatment groups. Plasma tHcy concentrations were higher (P < 0.05) in the enterally fed piglets that did not receive dietary Cys than in all other groups, which did not differ from each other. Therefore, both route of feeding and dietary supply of Met and Cys significantly affected the concentrations of plasma tHcy. These dramatic and rapid alterations in plasma tHcy warrant further studies of sulfur amino acid metabolism in neonatal animals.

Contrasting and cooperative effects of copper and iron deficiencies in male rats fed different concentrations of manganese and different sources of sulfur amino acids in an AIN-93G-based diet

Dietary nutrient interactions are important factors to consider in the study of nutrient status and requirements. Here, the effects of dietary interactions among copper (Cu), iron (Fe), manganese (Mn) and sulfur amino acids (SAA) on blood cell characteristics and enzyme activities were observed. Male rats (n = 8) were used in a 2 x 2 x 2 x 2 factorial design and fed an AIN-93G-based diet containing dietary Cu (<1 and 5 mg/kg), Fe (10 and 35 mg/kg), Mn (10 and 50 mg/kg) and either L-cystine (LCys) or DL-methionine (DLMet). Blood was analyzed by automated hematology cell counting and by flow cytometry. Severe Cu deficiency was verified by reductions in the activities of serum ceruloplasmin (1% of control), RBC superoxide dismutase (SOD1) (14% of control), liver cytochrome c oxidase activity (25% of control) and serum extracellular SOD (SOD3) activity (20% of controls). Because Cu is required for Fe utilization, many physiologic responses that require Fe were affected by both deficiencies, including lowered blood hemoglobin (Hgb), lower RBC volume and Hgb concentration, and an increased number of reticulocytes. Cu and Fe deficiencies together worsened some conditions, i.e., lower Hgb, lower RBC Hgb, increased RBC distribution width, increased number of reticulocytes and nucleated RBC, and a higher platelet count. Increasing dietary Mn had little effect on most variables, except to reduce serum Cu when dietary Cu was adequate but not when it was low, and to reduce RBC SOD1 activity when dietary Fe was low but not when it was adequate. Hgb concentrations were higher (P < 0.002) in Cu-deficient rats fed LCys than in those fed DLMet. There was no effect in Cu-adequate rats. Hgb was higher (P < 0.004) in Fe-adequate rats fed LCys than in those fed DLMet, with no effect in Fe-deficient rats. Although the anemia of Cu deficiency in AIN-93G-fed rats was not as pronounced as that reported in rats fed the AIN-76A-based diet, other manifestations of the deficiency were prominent.

Functional Sulfur Amino Acid Production and Seawater Remediation System by Sterile Ulva sp. (Chlorophyta)

Sterile Ulva, which is a macroalga, has the potential to grow stably; therefore, this seaweed is expected to be an efficient resource of functional food containing various nutrients such as sulfur amino acids, proteins, carbohydrates, and minerals. Ulva latuca was selected from the "Marine Park" in Tokyo Bay, and its growth rate (g-dry/[m2.d]) was measured using model reactors located on the land or on the surface of the sea at Yokohama. The growth rate of U. lactuca was recorded to be approx 20 g-dry/(m2.d), which is estimated to be 10 times greater than that in a natural field in the Marine Park. In addition, this growth rate was higher than that of conventional crops such as corn and rice on a farm or paddy. These data led us to newly design and propose a floating type of labor-efficient U. lactuca production system. d-Cysteinolic acid, which is included in U. lactuca as a major sulfur amino acid, inhibited the Fenton reaction, resulting in suppression of hydroxyl radical production and singlet oxygen. Addition of the sulfur amino acid (1 microM) to HepG2 cells markedly decreased the intracellular triglyceride level. Hence, this proposed facility also has the potential for industrial production of a valuable resource for the primary prevention of lifestyle-related diseases using enriched or eutrophied seawater.

L-cysteine sulphinate, endogenous sulphur-containing amino acid, inhibits rat brain kynurenic acid production via selective interference with kynurenine aminotransferase II

In the present study the effect of endogenous sulphur-containing amino acids, L-cysteine sulphinate, L-cysteate, L-homocysteine sulphinate and L-homocysteate, on the production of glutamate receptor antagonist, kynurenic acid (KYNA), was evaluated. The experiments comprised the measurements of (a). KYNA synthesis in rat cortical slices and (b). the activity of KYNA biosynthetic enzymes, kynurenine aminotransferases (KATs). All studied compounds reduced KYNA production and inhibited the activity of KAT I and/or KAT II, thus acting most probably intracellularly. L-Cysteine sulphinate in very low, micromolar concentrations selectively affected the activity of KAT II, the enzyme catalyzing approximately 75% of KYNA synthesis in the brain. L-Cysteine sulphinate potency was higher than other studied sulphur-containing amino acids, than L-aspartate, L-glutamate, or any other known KAT II inhibitor. Thus, L-cysteine sulphinate might act as a modulator of KYNA formation in the brain.

Modulation of hepatocyte thiol content by medium composition: implications for toxicity studies

Toxicity of compounds requiring glutathione for detoxification, thiol content and synthesis were determined in 24-h rat hepatocytes cultured in medium containing different concentrations of the sulphur amino acids. Glutathione synthesis was determined following prior depletion of glutathione with diethylmaleate. L-15 medium, which has high levels of cysteine and methionine (1 mM of each), provided some protection against dichloroacetone, dibromopropanol and dichloropropanol toxicity, and had a small effect on increasing glutathione content and synthesis, relative to Williams' medium E (WE) which has low levels (less than 0.5 mM) of both amino acids. However, WE containing N-acetylcysteine (NAC) (1 mM final cysteine concentration), with or without methionine (final concentration 1 mM), was a better cytoprotectant medium than L-15, markedly reducing toxicity of all three compounds, and rapidly (within 1.5 h) increasing cellular glutathione content. WE supplemented with methionine alone stimulated glutathione synthesis after an initial lag phase, and protected cultures against dichloropropanol, but not dibromopropanol or dichloroacetone, both of which are highly reactive in these cultures. There was a clear association between glutathione content at early time points in culture and toxicity observed at later time points, and overall these results indicate that differences in culture medium composition can alter intracellular glutathione content and xenobiotic toxicity.

Induction of microsomal epoxide hydrolase by sulfur amino acid deprivation via the pathway of C-Jun N-terminal kinase and its extracellular exposure during cell death

Microsomal epoxide hydrolase (mEH), an epoxide detoxifying enzyme and putative cell surface autoantigen, is inducible by xenobiotics and by certain pathophysiological conditions (e.g., tumorigenesis and protein-calorie malnutrition). The present study was designed to determine mEH expression in H4IIE cells during cell death initiated by sulfur amino acid deprivation (SAAD) and to identify the signaling pathway for the enzyme induction. SAAD induced cell death at 48-72 h with translocation of Bax to mitochondria and increased mitochondrial permeability with cytochrome c release, both of which were prevented by SB203580 or by dominant-negative JNK1 [JNK1(-)] stable transfection. Caspase-3 activity was only marginally increased by SAAD. Neither genomic DNA fragmentation nor poly(ADP-ribose) polymerase cleavage was observed during SAAD-induced cell death. Thus, SAAD induced cell death independent of caspase activation. This was supported by the observation that benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, a general caspase inhibitor, did not prevent cell death. The levels of mEH mRNA and protein were notably increased in cells under SAAD for 48-72 h. The induction of mEH occurred in parallel with cell death. Whereas SAAD-induced cell death resulted from both JNK1 and p38 kinase activation, mEH induction was decreased only by JNK1(-) transfection. Immunocytochemistry revealed that mEH protein was intensely stained in dying cells, cellular fragments and cell debris. Furthermore, the number of cells positive for surface mEH substantially increased by SAAD, as evidenced by flow cytometry analysis. These results demonstrated that SAAD induced nonapoptotic cell death with Bax translocation to mitochondria and mitochondrial cytochrome c release, but not through caspase-3 activation, and that mEH was induced by SAAD via the pathway of JNK1, but not ERK1/2 or p38 kinase, in parallel with cell death.

Endogenous sulphur-containing amino acids: potent agonists at presynaptic metabotropic glutamate autoreceptors in the rat central nervous system

We have recently demonstrated that presynaptically located metabotropic glutamate (mGlu) autoreceptors regulate synaptic glutamate release both in vitro and in vivo. We now report a positive modulatory action of the sulphur-containing amino acids (SCAAs), L-cysteic acid (CA) and L-cysteine sulphinic acid (CSA), at presynaptic group I mGlu receptors, specifically of the mGlu5 subtype, acting to enhance synaptic glutamate release from the rat forebrain in vitro. Neuronal glutamate release was monitored using electrically-evoked efflux of preloaded [(3)H]-D-aspartate from rat forebrain hemisections. Both CA (3 - 100 muM) and CSA (1 - 100 microM), in addition to the selective group I mGlu receptor agonist, (S)-3,5-dihydroxyphenylglycine ((S)-DHPG), concentration-dependently enhanced electrically-stimulated efflux of [(3)H]-D-aspartate from the rat forebrain slices. Basal efflux of label remained unchanged. The inhibitory activity of the broad spectrum mGlu receptor antagonist, (+/-)-alpha-methyl-4-carboxyphenylglycine ((+/-)-MCPG; 200 microM), coupled with the inactivity of the selective mGlu1 receptor antagonists, (R,S)-1-aminoindan-1,5-dicarboxylic acid ((R,S)-AIDA; 100 - 500 microM) and the more potent (+)-2-methyl-4-carboxyphenylglycine (LY367385; 10 microM) against these responses, indicates an action of the SCAAs at the mGlu5 receptor subtype. This proposal is supported by the potent inhibition of these responses by the selective, non-competitive mGlu5 receptor antagonist, 2-methyl-6-(phenylethynyl)pyridine (MPEP; 10 microM). The observed enhancement of the responses to high concentrations of CA by the selective mGlu5 receptor desensitization inhibitor, cyclothiazide (CYZ; 10 microM), is also consistent with this concept. Administration of the agonists in the presence of bovine serum albumin (BSA; 5 - 15 mg ml(-1)) markedly attenuated the positive modulatory responses observed, strongly supporting a role for arachidonic acid in the expression of these mGlu5 receptor-mediated responses. The regulatory actions of SCAAs on synaptic glutamate release demonstrated in the present study may provide a physiological function for these putative neurotransmitter amino acids in the mammalian brain. These central actions of the SCAAs may have wide-ranging implications for a range of neurological and neuropsychiatric disease states and their treatment.

Use of bioimpedance spectroscopy to estimate body water distribution in rats fed high dietary sulfur amino acids

The effect of dietary sulfur amino acids on bioelectric properties was studied in rats by using bioimpedance spectroscopy. Weanling rats were assigned to one of 12 groups in a factorially arranged experiment with dietary variables of supplemental sulfur amino acid (none, 10 g DL-methionine/kg or 10 g DL-homocystine/kg), pyridoxine hydrochloride (0 or 7.5 mg/kg) and nickel (0 or 1 mg/kg). After 9 wk of feeding, 20-h urine specimens were collected from food-deprived rats for measurements of creatinine, and then bioimpedance was measured with multifrequency (Hydra ECF/ICF 4200) and single-frequency (RJL Systems model 101) analyzers. Urinary creatinine excretion was measured by intracellular water (ICW), total body solid and urinary volume (R2 = 0.675). Extracellular water (ECW) did not add significantly to the model. Rats fed methionine had significantly lower total body water, ICW and ECW than rats fed no supplemental sulfur amino acid. Rats fed homocystine had significantly lower ECW and a significantly higher ratio of ICW to ECW. Rats fed methionine or homocystine had significantly lower capacitance corrected for body length and ICW than those fed no supplemental sulfur amino acids. These results suggest that dietary homocystine changes the distribution of body water and that sulfur amino acids can affect membrane porosity and/or membrane thickness.

Effects of dietary sulfur-containing amino acids on oxidative damage in rat liver caused by N-nitrosodimethylamine administration

Effects of dietary protein and S-containing amino acids on oxidative damage were investigated in rat liver. After feeding rats for 3 weeks from weaning, lower GSH levels and higher metallothionein (MT) levels were found in the liver of rats fed on a 10% soyabean-protein-isolate (SPI)-based diet than those fed on a 10% casein-based diet. After injection of N-nitrosodimethylamine (NDMA) at 20 mg/kg body weight, increases in lipid peroxide, determined as thiobarbituric-acid reactive substances (TBARS), and gamma-glutamyltransferase (GGT) activity in the liver were observed in the 10% SPI diet group. By supplementing the 10% SPI diet with 0.3% cystine or methionine, GSH levels were increased, while MT levels were decreased, and elevation in TBARS levels after NDMA injection was diminished. On the other hand, increase in GGT activity could be prevented only by methionine supplement. On a 20% SPI or casein diet, TBARS concentration and GGT activity were not altered after NDMA injection with concomitant increase in GSH levels and decrease in MT levels. These results indicate that sufficient amounts of methionine and cystine in a diet are important to protect the liver from oxidative damage after NDMA administration, and GSH plays a primary role in the cellular protective function when compared with MT.

Influence of the dietary ratio between sulphur containing amino acids and lysine on performance of growing-finishing pigs fed diets with various lysine concentrations

This study was conducted to determine the optimal ratio between sulphur containing amino acids and lysine in diets for growing-finishing pigs. Therefore, a total of five trials was carried out in which growing-finishing pigs (live weight range between 53 and 105 kg) were fed diets with various concentrations of lysine (0.62, 0.70 and 0.78%) and various ratios between sulphur containing amino acids to lysine. The diets contained 12.9 MJ ME per kg and 13.5% CP; the ratio between sulphur containing amino acids to lysine was adjusted by individual supplementation of the diets with DL-methionine. Increasing dietary levels of lysine from 0.62 to 0.78% continuously increased daily body weight gains and improved feed conversion efficiency as well as carcass characteristics. There was no significant interaction between the dietary lysine supply and the ratio between sulphur containing amino acids to lysine on animal performance parameters. This means that the effect of the ratio of sulphur containing amino acids to lysine was similar for various dietary lysine concentrations. The optimum ratio between sulphur containing amino acids to lysine according to quadratic regression analysis was 0.60, for both, growth and feed conversion. Reducing the ratio between sulphur containing amino acids to lysine from 0.59 to 0.53 and 0.47 reduced body weight by 3 and 12%, resp., and elevated the feed conversion ratio by 2 and 12%, resp. An increase of the ratio between sulphur containing amino acids to lysine from 0.59 to 0.65 failed to increase the animal performance. In contrast to animal performance parameters, optimum carcass characteristics (eye muscle area, fat area above eye muscle, meat-fat ratio and lean percentage) were achieved already at a ratio of sulphur containing amino acids to lysine of 0.53.

Dietary sulfur amino acid requirement of juvenile yellow perch fed the maximum cystine replacement value for methionine

We conducted three separate experiments designed to determine the dietary methionine requirement, ability of cyst(e)ine to spare methionine, and the total sulfur amino acid requirement (TSAA) of juvenile yellow perch when fed the maximal amount of cyst(e)ine. The purified basal diet used in each experiment contained 33.6 g of crude protein/100 g diet and 12.0 g of lipid/100 g diet. In the first experiment,;>L-methionine was added to eight diets providing methionine concentrations ranging from 0.37 to 1.77 g/100 g diet in gradations of 0.2 g/100 g diet. Diets were fed for 12 wk to juvenile yellow perch initially weighing 4.7 g/fish. Broken-line analyses of weight gain and feed efficiency data indicated that the dietary methionine requirement was 1.0 g/100 g diet (3.1 g TSAA/100 g dietary protein) and 1.1 g/100 g diet (3.4 g TSAA/100 g dietary protein), respectively. In the second experiment, various ratios of L-cyst(e)ine and L-methionine were added to the basal diet and fed for 12 wk to determine the cyst(e)ine replacement value of yellow perch initially weighing 19.3 g/fish. Weight gain and feed efficiency (FE) data indicated that cyst(e)ine spared up to 51% of the methionine requirement. In the final experiment, graded levels of cyst(e)ine plus methionine in a ratio of 51:49 were added to the basal diet in gradations of 0.1 g/100 g diet (0.5 to 1.2 g TSAA/100 g diet) to determine the dietary total sulfur amino acid requirement. Diets were fed to satiation for 10 wk to fish initially weighing 8. 1 g. Broken-line analyses of weight gain, feed intake and FE data indicated that the dietary TSAA requirement was 0.85, 0.87 and 1.0 g of TSAA/100 g diet (2.5 to 3.0 g of TSAA/100 g of dietary protein), respectively. The majority of dietary TSAA requirements of fish are in the range of 2 to 4 g/100 g of dietary protein and are generally similar to those of both birds and swine, but lower than estimates for rodents.

Antioxidant properties of the decarboxylated dimer of aminoethylcysteine ketimine: assessment of its ability to scavenge peroxynitrite

The natural sulfur compound aminoethylcysteine ketimine decarboxylated dimer (AECK dimer) has been investigated for its ability to act as peroxynitrite scavenger. It has been found that the product efficiently protects against the nitration of tyrosine and the inactivation of alpha1-antiproteinase by peroxynitrite. The tyrosine nitration can be completely prevented by 100 microM AECK dimer which appears as effective as the antioxidants glutathione and N-acetylcysteine. The AECK dimer was also found to limit surface charge alteration of low density lipoprotein induced by peroxynitrite. These findings indicate that the AECK dimer is a strong protective agent against peroxynitrite damage and that it could play an important role in the defence against oxidative stress in human diseases.

Antioxidant activity of aminoethylcysteine ketimine decarboxylated dimer on copper-induced LDL oxidation

Aminoethylcysteine ketimine decarboxylated dimer (AECK-DD), a member of a family of natural cyclic sulfur-containing aminoacids, recently detected in biological samples, protects low density lipoprotein (LDL) against copper-mediated oxidation, as assessed by monitoring the kinetics of conjugated diene formation, thiobarbituric acid-reactive substances production and LDL-tryptophan fluorescence quenching. Moreover, AECK-DD exerts a protective effect also against metal-independent, peroxyl radical-induced lipoprotein oxidation. It is of note that the concentrations exerting a protective effect against LDL oxidation are similar to those found in biological samples.

Sulphur-containing amino acids are agonists for group 1 metabotropic receptors expressed in clonal RGT cell lines

Comparison of the pharmacological effects of a range of sulphur-containing amino acids on human mGluR1alpha and mGluR5a has been undertaken. cDNAs of each mGluR were transfected into a Syrian hamster tumour cell line AV12-664 that was previously transfected with the rat glutamate-aspartate transporter protein (GLAST). The L-isomers of cysteine sulphinic acid (CSA), homocysteine sulphinic acid (HCSA), cysteic acid (CA) and serine-O-sulphate (SOS) stimulated PI hydrolysis in human mGluR1alpha and mGluR5a cells with full agonist effects. D-CSA, the only active D-isomer, was a partial agonist for mGluR5a whereas L-sulphocysteine (S-CYS) showed weak agonist-like effects at high concentrations on both mGluR1alpha and mGluR5a. L-Homocysteic acid was inactive on both mGluR1alpha and mGluR5a cells. Treatment of mGluR cultures with glutamate pyruvate transaminase did not alter the potencies of the S-amino acids on PI hydrolysis responses. Inhibitor constants (Ki) obtained for L-HCSA, L-CSA, L-CA and L-SOS in [3H]glutamate receptor binding studies with mGluR1alpha cells indicated that L-HCSA, L-CSA, L-CA and L-SOS can bind specifically to mGluR1 with L-HCSA showing the highest affinity. These results confirm that certain endogenously produced S-amino acids may interact directly with group 1 mGluRs.

Lanthionine ketimine and S-(2-aminoethyl)-L-cysteine ketimine induce the tyrosyl phosphorylation of 45 kDa protein in parallel with its stimulation of superoxide generation in human neutrophils

Human peripheral blood polymorphonuclear leukocytes were preincubated with lanthionine, S-(2-aminoethyl)-L-cysteine, and some of their derivatives found in normal human urine and bovine brain. Among these compounds, lanthionine ketimine and to a lesser extent S-(2-aminoethyl)- L-cysteine ketimine enhanced the N-formyl-methionyl-leucyl-phenylalanine-induced superoxide generation. These ketimines induced tyrosyl phosphorylation of 45 kDa protein of cells. The tyrosyl phosphorylation was markedly increased with time, and the phosphorylation process was dependent on the concentration of both ketimines. However, lanthionine, 1,4-thiomorpholine-3,5-dicarboxylic acid, S-(2-aminoethyl)-L-cysteine and 1,4-thiomorpholine-3-carboxylic acid were without effect both on superoxide generation and on tyrosyl phosphorylation of 45 kDa protein. Lanthionine ketimine and S-(2-aminoethyl)-L-cysteine ketimine also enhanced superoxide generation induced by opsonized zymosan but not the one induced by arachidonic acid and phorbol 12-myristate 13-acetate. Ketimine-primed superoxide generation and tyrosyl phoshorylation of 45 kDa protein were inhibited by genistein, an inhibitor of protein tyrosine kinase, but not by 1-(5-isoquinoline sulfonyl)-2- methylpiperazine, an inhibitor of protein kinase C.

Sulphur-containing amino acids modulate noradrenaline release from hippocampal slices

The L- and D-enantiomers of the sulphur-containing amino acids (SAAs)-homocysteate, homocysteine sulphinate, cysteate, cysteine sulphinate, and S-sulphocysteine-stimulated [3H] noradrenaline release from rat hippocampal slices in a concentration-dependent manner. The relative potencies of the L-isomers (EC50 values of 1.05-1.96 mM) were of similar order to that of glutamate (1.56 mM), which was 10-fold lower than that of NMDA (0.15 mM), whereas the D-isomers exhibited a wider range of potencies (0.75 to > 5 mM). All stimulatory effects of the SAAs were significantly inhibited by the voltage-sensitive Na+ channel blocker tetrodotoxin (55-71%) and completely blocked by addition of Mg2+ or Co2- to the incubation medium. All SAA-evoked responses were concentration-dependently antagonized by the selective NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (IC50 values of 3.2 - 49.5 microM). 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist, at 100 microM inhibited the [3H]noradrenaline release induced by glutamate and NMDA (65 and 76%, respectively) and by all SAAs studied (65-85%), whereas 10 microM CNQX only inhibited the effects of S-sulpho-L-cysteine and L- and D-homocysteate (33, 32, and 44%, respectively). However, the more selective AMPA/kainic acid receptor antagonist 6-nitro-7-sulphamoylbenzo (f) quinoxaline-2,3-dione (100 microM), which did not antagonize the [3H]noradrenaline release induced by glutamate and NMDA, reduced only the S-sulpho-L-cysteine-evoked response (25%). Thus, the stimulation of Ca2(+)-dependent [3H]noradrenaline release from hippocampal slices elicited by the majority of the SAAs appears to be mediated by the NMDA receptor.

Hepatic betaine-homocysteine methyltransferase activity in the chicken is influenced by dietary intake of sulfur amino acids, choline and betaine

There is much interest in the metabolism of homocysteine, because elevated plasma homocysteine [hyperhomocyst(e)inemia] is an independent risk factor for the development of cardiovascular disease. Four chick assays were conducted to determine the effects of varying dietary sulfur amino acids, choline and betaine on the activity of hepatic betaine-homocysteine methyltransferase (BHMT), an enzyme likely to be important in modulating plasma homocysteine. In Experiment 1, chicks were fed a purified crystalline amino acid diet containing adequate sulfur amino acids and choline. Excess dietary methionine, or the combination of excess cystine with choline or betaine, caused a small increase (P < 0.05) in BHMT activity. In Experiment 2, use of a methionine-deficient purified diet resulted in a threefold increase (P < 0.05) in BHMT activity, and addition of choline or betaine further increased (P < 0.05) BHMT activity. In Experiment 3, use of a methionine-deficient corn-peanut meal diet increased BHMT (P < 0.05) relative to that of chicks supplemented with adequate methionine, and addition of surfeit choline to the methionine-deficient basal diet caused a further increase (P < 0.05). In Experiment 4, addition of both surfeit choline and surfeit betaine to the methionine-deficient corn-peanut meal diet caused an increase (P < 0.05) in BHMT activity relative to that observed in chicks fed the methionine-deficient basal diet. These assays show that large increases in BHMT activity can be produced under methionine-deficient conditions, especially in the presence of excess choline or betaine.

Effects of amino acids on the growth of an anaerobic rumen fungus Neocallimastix sp N 13

The amino acid requirements of Neocallimastix sp N 13 isolated from sheep rumen were studied using supplements containing either ten essential amino acids (10 EAA) or eight nonessential amino acids (8 NEAA), or both (18 AA). Although the fungus could grow in a medium containing ammonium sulphate as the sole source of nitrogen, amino acid supplements, especially 18 AA, greatly stimulated its growth. Omission of the sulphur-containing amino acids (SCAA) from the 18 AA mixture markedly reduced the growth-stimulating effect, and sulphide, but not sulphate, substituted for SCAA only partly compensated for this omission. Omission of aromatic, branched chain, basic, acidic, aliphatic and hydroxy amino acids, and proline, singly or in combination, all reduced fungal growth to some degree as compared with the 18 AA supplement. A three amino acid (leucine, methionine and histidine) supplement was a potent stimulator for the fungus, whereas another three amino acid combination (glutamic acid, methionine and serine) was ineffective. The results indicated that Neocallimastix sp N 13 effectively utilized amino acids for its growth, but the requirements for the different amino acids differed from those of N patriciarum.

Copper-induced changes in the urea uptake and urease activity in the cyanobacteria Anabaena doliolum and Anacystis nidulans: interaction with sulphur containing amino acids

Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans. Copper, at and above 5 mumol/L concentration, inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner. However, the urea uptake and urease activity systems in A. nidulans appeared slightly more tolerant to copper than than of A. doliolum. The inhibitory effect of copper on urea uptake and urease activity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not do so, indicating the involvement of sulfhydryl (-SH) groups in the assimilation of urea in cyanobacteria.

Supplemental dietary cystine elevates kidney metallothionein in rats by a mechanism involving altered zinc metabolism

Dietary sulfur-containing amino acids influence zinc and copper status. This study was conducted to investigate the relationship between the status of these elements and tissue metallothionein in rats fed diets supplemented with sulfur-containing amino acids. In a series of experiments, a diet containing 100 g casein/kg diet was unsupplemented or supplemented with L-cystine (3-50 g/kg diet) or L-methionine (3 or 30 g/kg diet). Kidney concentrations of zinc and copper in rats fed the diet supplemented with high levels of cystine (25 or 50 g/kg) were significantly higher than those in rats fed the unsupplemented diet. Kidney concentrations of metallothionein and metallothionein mRNA were also significantly higher in rats fed cystine-supplemented diets. There was a correlation (r = 0.838, P < 0.01) between the levels of zinc and metallothionein in kidney of rats fed the diets with different levels of cystine and zinc. However, in the rats fed the diets with different levels of cystine and copper, the correlation was not as strong (r = 0.587, P < 0.01). The changes in kidney metallothionein concentration due to the addition of 3 or 30 g/kg cystine were associated with parallel changes in serum zinc concentration and in apparent absorption of zinc, but not in serum copper concentration or apparent absorption of copper. Addition of 3 or 30 g methionine/kg diet to the diet did not affect kidney concentrations of metallothionein or zinc. These results indicate that supplementation of cystine to the diet can induce kidney metallothionein through a mechanism involving altered zinc metabolism.

Rats fed a low protein diet supplemented with sulfur amino acids have increased cysteine dioxygenase activity and increased taurine production in hepatocytes

The metabolism of cysteine and cysteinesulfinate and the activities of key enzymes in cysteine catabolic pathways were investigated in hepatocytes isolated from rats fed a basal (100 g casein/kg) diet or the diet supplemented with L-methionine (3 or 10 g/kg diet) or the sulfur equivalent as L-cystine (2.4 or 8 g/kg diet). Cysteine dioxygenase activity was higher in hepatocytes from rats fed diets with the higher level of sulfur amino acid supplementation, and the higher enzyme activity was paralleled by a greater total catabolite production (taurine + sulfate) from cysteine. Taurine production as a percentage of total cysteine catabolism was significantly greater in hepatocytes from rats fed the diet with excess methionine or cystine (basal, 22%; excess methionine, 61%, excess cystine, 49%). Glutathione production was markedly lower in hepatocytes from rats fed excess sulfur amino acids such that total cysteine utilization was similar for all dietary treatments. Cysteinesulfinate decarboxylase activity and catabolism of cysteinesulfinate by hepatocytes were unaffected by the dietary supplementations. Results are in contrast to previous studies in which increased dietary protein resulted in decreased cysteinesulfinate decarboxylase activity and decreased partitioning of cysteinesulfinate to taurine vs. sulfate. Thus, sulfur amino acids may be less effective than protein in decreasing cysteinesulfinate decarboxylase activity and may result in a pattern of sulfur catabolite production from cysteine that favors taurine production.

Aminoethylcysteine ketimine decarboxylated dimer protects submitochondrial particles from lipid peroxidation at a concentration not inhibitory of electron transport

In contrast with other inhibitors of the NADH dehydrogenase of the respiratory chain, the decarboxylated dimer of aminoethylcysteine ketimine protects bovine heart submitochondrial particles (SMP) from the NADH-Fe(+3)-ADP-induced lipid peroxidation. This effect, measured as inhibition of malondialdehyde formation, is concentration-dependent in the range 0.02-0.2 mM. This range of concentration is not inhibitory on NADH-oxidase activity of SMP. Furthermore the dimer is able to counteract the malondialdehyde formation stimulated by the Complex I inhibitors rotenone and N-methyl-4-phenylpyridinium (MPP+).

Induction of fictive locomotion by sulphur-containing amino acids in an in vitro newborn rat preparation

The role of the sulphur-containing amino acids (SAAs) in the initiation of fictive locomotion was tested in an isolated spinal cord preparation from newborn rats. These substances were bath-applied and the fictive locomotion was recorded in the lumbar ventral roots. It emerged from this study that all the compounds tested could trigger an organized pattern (alternating left and right bursts of activity) with a dose-dependent response. However, specific frequency and concentration ranges were observed with each of these SAAs. Moreover, a clear-cut difference between D and L isomers in the ability of the SAAs to induce this activity was observed; the SAAs of the D-forms were found to be generally more potent than those of the L-forms. The effects of the SAAs were found to be mediated by both NMDA and non-NMDA receptors, since they were blocked in a dose-dependent manner by the specific antagonists of these receptors. Moreover, it was observed that beta-p-chlorophenylglutamic acid, an uptake inhibitor of homocysteic acid (HCA), potentiated the effect of exogenously applied HCA, which supports the idea that HCA may act as a transmitter. The sulphuric and non-sulphuric amino acids were also classified in their order of potency. The most potent compound turned out to be D-homocysteine sulphinic acid, while D-cysteine sulphinic acid was the least potent. It also emerged that the maximal frequencies obtained with SAAs and excitatory amino acids were in the same range, which might correspond to the maximal limits of this system.

Glutamate metabotropic receptor activation in neonatal rat cerebral cortex by sulphur-containing excitatory amino acids

The sulphur-containing acidic amino acids (SAAs) display neuroexcitatory actions similar to those of L-glutamate and are widely regarded as bona fide transmitter candidates. In this study, L-cysteine sulphinic acid, L-cysteic acid, DL-homocysteic acid and L-homocysteine sulphinic acid were investigated for their ability to stimulate phosphatidylinositol hydrolysis in rat pup cerebrocortical slices and compared with L-glutamate and the selective agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD). Each of the SAAs possessed agonist activity at metabotropic glutamate receptors (mGluRs) and, although they exhibited lower efficacy than L-glutamate, they were more potent (EC50s of 401-487 microM compared with 791 microM for L-glutamate). These data are consistent with the possibility that SAAs may have a physiological role as endogenous activators of metabotropic (and presumably ionotropic) excitatory amino acid receptors.

Effect of dietary protein and sulfur-containing amino acids on urinary metabolites in rats injected with chlorobenzene

Rats were fed for 10 days a 10 or 20% casein diet, or the diets with 0.3% DL-methionine or L-cystine. Rats fed the 20% casein exceeded those fed the 10% casein in growth, hepatic glutathione (GSH) levels, and microsomal drug-metabolizing activities including cytochrome P-450, aminopyrine N-demethylase, and aniline hydroxylase. Supplement with methionine or cystine had significantly elevated hepatic GSH, regardless of the casein content. After the feeding, rats were intraperitoneally injected with chlorobenzene (0.5 mmol/kg body weight), and the urinary metabolites (4-chlorophenylmercapturic acid (4-CPMA), 2-, 3- and 4-chlorophenol (CPs), 4-chlorocatechol (4-CC), and 2-, 3- and 4-chlorophenylmethylsulfide (CPMSs) ) were measured for 24 hours post-injection. Rats fed the 20% casein exceeded those fed the 10% casein in 4-CPMA, CPs, and in total urinary metabolites. Supplement with methionine or cystine to the 10% casein significantly increased 4-CPMA and decreased 4-CC. Supplement with methionine or cystine to the 20% casein also significantly increased 4-CPMA excretion, but had no effect on urinary 4-CC. The highest urinary excretion of CPMSs was observed in rats fed the 10% casein. Both increase of dietary protein and addition of the sulfur-containing amino acids decreased urinary CPMSs. These results indicate that total urinary metabolites are strongly associated with the microsomal drug-metabolizing activity, formation of the mercapturic acid is dependent on the hepatic GSH level, and the urinary CPMS level is independent on the mercapturic acid formation.

Cytotoxic actions and effects on intracellular Ca2+ and cGMP concentrations of sulphur-containing excitatory amino acids in cultured cerebral cortical neurons

Effects of the sulphur-containing acidic amino acids (SAAs) cysteic acid (CA), homocysteic acid (HCA), cysteine sulphinic acid (CSA), homocysteine sulphinic acid (HCSA), and S-sulphocysteine (SC) on intracellular concentrations of Ca2+ ([Ca2+]i) and cGMP ([cGMP]i) as well as their cytotoxic actions were investigated in cultured cerebral cortical neurons. The glutamate receptor subtype selective antagonists APV (D-(-)-2-amino-5-phosphonopentanoate) acting on N-methyl-D-aspartate (NMDA) receptors and DNQX (6,7-dinitroquinoxaline-2,3-dione) acting on non-NMDA receptors were employed to obtain information about the involvement of glutamate receptor subtypes in these actions of the SAAs. It was found that all SAAs exerted a cytotoxic action on the neurons. The ED50 values for CSA, CA, HCSA, and HCA were around 30 to 50 microM and that for SC was about 150 microM. The glutamate transport blocker L-aspartate-beta-hydroxamate increased the efficacy of CSA and CA but had no effect on the cytotoxic actions of the remaining SAAs. In case of CA, HCA, and SC the cytotoxicity could be prevented by APV alone and for HCSA, DNQX could block the toxic action. DNQX reduced the toxicity of HCA somewhat but the presence of APV was required for complete protection. CSA toxicity could only be blocked by the combination of APV and DNQX. All SAAs induced an increase in [cGMP]i and [Ca2+]i and with regard to [Ca2+]i SC was the most potent and CA the least potent SAA. The effect of all SAAs on [cGMP]i could be blocked by APV alone whereas DNQX had no effect except in the case of HCSA where the response was blocked completely and HCA where the response was inhibited by 75%.(ABSTRACT TRUNCATED AT 250 WORDS)