Tryptophan Predicts the Risk for Future Type 2 Diabetes

PubMed Central

Chen, Tianlu; Zheng, Xiaojiao; Ma, Xiaojing; Bao, Yuqian; Ni, Yan; Hu, Cheng; Rajani, Cynthia; Huang, Fengjie; Zhao, Aihua; Jia, Weiping; Jia, Wei

2016-01-01

Recently, 5 amino acids were identified and verified as important metabolites highly associated with type 2 diabetes (T2D) development. This report aims to assess the association of tryptophan with the development of T2D and to evaluate its performance with existing amino acid markers. A total of 213 participants selected from a ten-year longitudinal Shanghai Diabetes Study (SHDS) were examined in two ways: 1) 51 subjects who developed diabetes and 162 individuals who remained metabolically healthy in 10 years; 2) the same 51 future diabetes and 23 strictly matched ones selected from the 162 healthy individuals. Baseline fasting serum tryptophan concentrations were quantitatively measured using ultra-performance liquid chromatography triple quadruple mass spectrometry. First, serum tryptophan level was found significantly higher in future T2D and was positively and independently associated with diabetes onset risk. Patients with higher tryptophan level tended to present higher degree of insulin resistance and secretion, triglyceride and blood pressure. Second, the prediction potential of tryptophan is non-inferior to the 5 existing amino acids. The predictive performance of the combined score improved after taking tryptophan into account. Our findings unveiled the potential of tryptophan as a new marker associated with diabetes risk in Chinese populations. The addition of tryptophan provided complementary value to the existing amino acid predictors. PMID:27598004

Inhibition of Tryptophan on AA 2024 in Chloride-Containing Solutions

NASA Astrophysics Data System (ADS)

Li, Xing; Xiang, Bin; Zuo, Xiu-Li; Wang, Qin; Wei, Zi-Dong

2011-03-01

The inhibitory effects of tryptophan on the corrosion of AA 2024 in 1 M HCl, 20% (wt.%) CaCl2, and 3.5% (wt.%) NaCl solutions were investigated via polarization techniques, electrochemical impedance spectroscopy, and weight loss methods. The scanning electron microscope technique was employed to observe corrosion morphology. The results suggest that AA 2024 was corroded in these three corrosive media to some extent and that tryptophan can significantly inhibit the corrosion of aluminum alloys. The inhibition efficiency (η) increased with increasing concentrations of tryptophan, and the best inhibition efficiency exhibited was about 87% in 1 M HCl solution with 0.008 M tryptophan. Tryptophan acted as a cathodic corrosion inhibitor and affected the hydrogen evolution reaction, which was the main electrode reaction in the 1 M HCl solution. In solutions with 20% CaCl2 and 3.5% NaCl, tryptophan was adsorbed onto anodic areas, thus increasing the activation energy of the interface reaction as an anodic corrosion inhibitor. The Dmol3 program of Material Studio 4.0 was used to obtain the optimized geometry of the tryptophan inhibitor and some quantum-chemical parameters. Front orbital distributions and Fukui indices indicate that the molecular active reaction zones were located in the indole ring of tryptophan.

Destabilization of artificial biomembrane induced by the penetration of tryptophan

NASA Astrophysics Data System (ADS)

Chen, Liuhua; Gan, Lihua; Liu, Mingxian; Fan, Rong; Xu, Zijie; Hao, Zhixian; Chen, Longwu

2011-03-01

The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. π-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 × 10 -3 mol L -1, the limiting molecular area of lecithin increased from 110.5 to 138.5 Å 2, but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m -1, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 × 10 6 Ω and 3.573 × 10 -8 F to 1.391 × 10 6 Ω and 3.340 × 10 -8 F when the concentration of tryptophan increased from 0 to 2 × 10 -3 mol L -1. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.

The effect of insulin upon the influx of tryptophan into the brain of the rabbit.

PubMed

Daniel, P M; Love, E R; Moorhouse, S R; Pratt, O E

1981-03-01

1. The effect of hyperinsulinaemia upon the influx of tryptophan into the brain was determined. A raised level of insulin was maintained in the circulation of rabbits for periods of up to 120 min by means of a continuous, programmed intravenous injection of the hormone, given by an electronically controlled variable-drive syringe. A similar, appropriately programmed, intravenous injection of glucose, given simultaneously with the insulin, maintained the concentration of the blood glucose within normal limits throughout each experiment, so that the results were not vitiated by the development of hypoglycaemia. 2. Raised levels of insulin in the blood affect the supply of tryptophan to the brain in two opposing ways: (a) by increasing the binding of tryptophan to the albumin in the blood, thereby reducing the level of the free tryptophan in the circulation by about a half, which would decrease the influx of tryptophan into the brain; (b) by simultaneously reducing the levels in the blood of six or more of the amino acids which compete with tryptophan for transport carriers into the brain, which would increase the influx of tryptophan. The net result of these two opposing effects is that insulin causes only a slight increase in the influx of tryptophan into the brain. 3. To account in quantitative terms for the effect of insulin upon the influx of tryptophan into the brain it proved necessary to make one assumption. This assumption was that a predictable proportion of the tryptophan which is loosely bound to blood albumin is being stripped off this protein by the transport carrier located on the luminal surface membranes of the endothelial cells during the passage of the blood through the cerebral capillaries. If this assumption is accepted the work reported here explains adequately the effect of insulin on the influx of tryptophan into the brain.

Inhibition of hormonal and behavioral effects of stress by tryptophan in rats.

PubMed

Gul, Sumera; Saleem, Darakhshan; Haleem, Muhammad A; Haleem, Darakhshan Jabeen

2017-11-03

Stress in known to alter hormonal systems. Pharmacological doses of tryptophan, the essential amino acid precursor of serotonin, increase circulating leptin and decrease ghrelin in normal healthy adults. Because systemically injected leptin inhibits stress-induced behavioral deficits and systemically injected serotonin modulates leptin release from the adipocytes, we used tryptophan as a pharmacological tool to modulate hormonal and behavioral responses in unstressed and stressed rats. Leptin, ghrelin, serotonin, tryptophan, and behavior were studied in unstressed and stressed rats following oral administration of 0, 100, 200, and 300 mg/kg of tryptophan. Following oral administration of tryptophan at a dose of 300 mg/kg, circulating levels of serotonin and leptin increased and those of ghrelin decreased in unstressed animals. No effect occurred on 24-hours cumulative food intake and elevated plus maze performance. Exposure to 2 hours immobilization stress decreased 24 hours cumulative food intake and impaired performance in elevated plus maze monitored next day. Serum serotonin decreased, leptin increased, and no effect occurred on ghrelin. Stress effects on serotonin, leptin, food intake, and elevated plus maze performance did not occur in tryptophan-pretreated animals. Tryptophan-induced decreases of ghrelin also did not occur in stressed animals. The findings show an important role of serum serotonin, leptin, and ghrelin in responses to stress and suggest that the essential amino acid tryptophan can improve therapeutics in stress-induced hormonal and behavioral disorders.

24h withdrawal following repeated administration of caffeine attenuates brain serotonin but not tryptophan in rat brain: implications for caffeine-induced depression.

PubMed

Haleem, D J; Yasmeen, A; Haleem, M A; Zafar, A

1995-01-01

Caffeine injected at doses of 20, 40 and 80 mg/kg increased brain levels of tryptophan, 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat brain. In view of a possible role of 5-HT in caffeine-induced depression the effects of repeated administration of high doses of caffeine on brain 5-HT metabolism are investigated in rats. Caffeine was injected at doses of 80 mg/kg daily for five days. Control animals were injected with saline daily for five days. On the 6th day caffeine (80 mg/kg) injected to 5 day saline injected rats increased brain levels of tryptophan, 5-HT and 5-HIAA. Plasma total tryptophan levels were not affected and free tryptophan increased. Brain levels of 5-HT and 5-HIAA but not tryptophan decreased in 5 day caffeine injected rats injected with saline on the 6th day. Plasma total and free tryptophan were not altered in these rats. Caffeine-induced increases of brain tryptophan but not 5-HT and 5-HIAA were greater in 5 day caffeine than 5 day saline injected rats. The findings are discussed as repeated caffeine administration producing adaptive changes in the serotonergic neurons to decrease the conversion of tryptophan to 5-HT and this may precipitate depression particularly in conditions of caffeine withdrawal.

TRYPTOPHANASE-TRYPTOPHAN SYNTHETASE SYSTEMS IN ESCHERICHIA COLI I.

PubMed Central

Freundlich, Martin; Lichstein, Herman C.

1962-01-01

Freundlich, Martin (University of Minnesota, Minneapolis) and Herman C. Lichstein. Tryptophanase-tryptophan synthetase systems in Escherichia coli. I. Effect of tryptophan and related compounds. J. Bacteriol. 84:979–987. 1962.—The effect of tryptophan and related compounds on tryptophanase and tryptophan synthetase formation in Escherichia coli was determined. Several of these compounds stimulated the formation of tryptophanase while concomitantly decreasing the production of synthetase. A number of tryptophan analogues were found to inhibit growth. The possible mode of action of these substances was examined further. 5-Hydroxytryptophan greatly inhibited the formation of synthetase and also reduced growth. Its inhibitory action on growth was attributed, at least partially, to the false feedback inhibition of anthranilic acid formation. Tryptamine was found to be a potent inhibitor of the activity of synthetase, as well as of the enzyme(s) involved in the synthesis of anthranilic acid from shikimic acid. However, growth reduction was only partially reversed by tryptophan. Indole-3-acetic acid and indole-3-propionic acid decreased growth and increased the formation of synthetase six- to eightfold. The action of these compounds was ascribed to their ability to block the endogenous formation of tryptophan. PMID:13959621

Differences in fluorescence profiles from breast cancer tissues due to changes in relative tryptophan content via energy transfer: tryptophan content correlates with histologic grade and tumor size but not with lymph node metastases

NASA Astrophysics Data System (ADS)

Sordillo, Laura A.; Sordillo, Peter P.; Budansky, Yury; Pu, Yang; Alfano, Robert R.

2014-12-01

The correlation between histologic grade, an increasingly important measure of prognosis for patients with breast cancer, and tryptophan levels from tissues of 15 breast carcinoma patients was investigated. Changes in the relative content of key native organic biomolecule tryptophan were seen from the fluorescence spectra of cancerous and paired normal tissues with excitation wavelengths of 280 and 300 nm. Due to a large spectral overlap and matching excitation-emission spectra, fluorescence resonance energy transfer from tryptophan-donor to reduced nicotinamide adenine dinucleotides-acceptor was noted. We used the ratios of fluorescence intensities at their spectral emission peaks, or spectral fingerprint peaks, at 340, 440, and 460 nm. Higher ratios correlated strongly with high histologic grade, while lower-grade tumors had low ratios. Large tumor size also correlated with high ratios, while the number of lymph node metastases, a major factor in staging, was not correlated with tryptophan levels. High histologic grade correlates strongly with increased content of tryptophan in breast cancer tissues and suggests that measurement of tryptophan content may be useful as a part of the evaluation of these patients.

Chromatographic analysis of tryptophan metabolites

PubMed Central

Sadok, Ilona; Gamian, Andrzej

2017-01-01

The kynurenine pathway generates multiple tryptophan metabolites called collectively kynurenines and leads to formation of the enzyme cofactor nicotinamide adenine dinucleotide. The first step in this pathway is tryptophan degradation, initiated by the rate‐limiting enzymes indoleamine 2,3‐dioxygenase, or tryptophan 2,3‐dioxygenase, depending on the tissue. The balanced kynurenine metabolism, which has been a subject of multiple studies in last decades, plays an important role in several physiological and pathological conditions such as infections, autoimmunity, neurological disorders, cancer, cataracts, as well as pregnancy. Understanding the regulation of tryptophan depletion provide novel diagnostic and treatment opportunities, however it requires reliable methods for quantification of kynurenines in biological samples with complex composition (body fluids, tissues, or cells). Trace concentrations, interference of sample components, and instability of some tryptophan metabolites need to be addressed using analytical methods. The novel separation approaches and optimized extraction protocols help to overcome difficulties in analyzing kynurenines within the complex tissue material. Recent developments in chromatography coupled with mass spectrometry provide new opportunity for quantification of tryptophan and its degradation products in various biological samples. In this review, we present current accomplishments in the chromatographic methodologies proposed for detection of tryptophan metabolites and provide a guide for choosing the optimal approach. PMID:28590049

Influence of tryptophan and related compounds on ergot alkaloid formation in Claviceps purpurea (FR.) Tul.

PubMed

Erge, D; Schumann, B; Gröger, D

1984-01-01

L-Tryptophan did not exert any influence on peptide alkaloid formation in an ergotamine and in an ergosine-accumulating C. purpurea strain. A different picture was observed in a series of related C. purpurea strains. Tryptophan showed a slight stimulatory effect on the ergotoxine producer Pepty 695/S. A blocked mutant of it, designated as Pepty 695/ch which was able to accumulate secoclavines gave similar results. In a high-yielding elymoclavine strain Pepty 695/e, the progeny of the former one, tryptophan up to a concentration of 25 mM stimulated remarkably clavine biosynthesis. Furthermore, tryptophan could overcome the block of synthesis by inorganic phosphate. Increased specific activities of chanoclavine cyclase but not DMAT synthetase were observed in cultures of strain Pepty 695/e supplemented with tryptophan. 5-Methyltryptophan and bioisosteres of tryptophan were ineffective in alkaloid stimulation. These results are compared with those obtained with the grass ergot strain SD 58 and discussed with the relation to other induction phenomena.

Kinetics and mechanism of the condensation of pyridoxal hydrochloride with L-tryptophan and D-tryptophan, and the chemical transformation of their products

NASA Astrophysics Data System (ADS)

Pishchugin, F. V.; Tuleberdiev, I. T.

2017-10-01

The kinetics and mechanism of interaction between pyridoxal and L-tryptophan, D-tryptophan, and their derivatives are studied. It is found that condensation reactions proceed via three kinetically distinguishable stages: (1) the rapid intraplanar addition of the NH2 groups of the amino acids to pyridoxal with the formation of amino alcohols; (2) the rotational isomerism of amino alcohol fragments with their subsequent dehydration and the formation of a Schiff base with a specific configuration; (3) the abstraction of α-hydrogen in the product of condensation of pyridoxal with L-tryptophan, or the abstraction of CO2 in the product of condensation of pyridoxal with D-tryptophan with the formation of quinoid structures, hydrolysis of which results in the preparation of pyridoxamine and keto acid or pyridoxal and tryptamine, respectively. Schiff bases resistant to further chemical transformations are formed in the reaction with tryptophan methyl ester.

Tryptophan metabolism via transamination. In vitro aminotransferase assay using dinitrophenylhydrazine method.

PubMed

Drsata, Jaroslav

2003-01-01

Transamination of tryptophan belongs to minor pathways of amino acid metabolism. The present paper describes conditions for application of dinitrophenylhydrazine method, originally prepared for alanine aminortansferase and aspartate aminotransferase assay, to the measurement of tryptophan transamination catalysed by any of the enzymes mentioned above. The method was tested using purified pig heart AST. While the free enzyme showed a characteristic absorption profile with the maxima at 360 and 430 nm, the course of transamination of tryptophan was confirmed by the measurement of UV-VIS spectral changes of the coenzyme in the active site of the enzyme in the presence of the amino acid substrate only, when tryptophan caused a shift of the peak from 360 nm to 330 nm due to a change of the pyridoxal form to the pyridoxamine form (= the first step of ping-pong transaminating reaction). A general limitation of dinitrophenylhydrazine method is the interference of hydrazones formed from the coenzyme pyridoxal-5'-phosphate and from the oxo- substrate 2-oxoglutarate, showing the absorption maxima at 492 nm and 388 nm, respectively with the hydrazones formed by the oxo- products (pyruvate and/or oxaloacetate in the case of ALT/AST, the absorption maxima at 443 nm in our measurements). In the case of tryptophan transamination, indolepyruvate as the oxo- product of a catalysed reaction forms dinitrophenylhydrazone, which has, besides a maximum at 435 nm, a distinct peak at 542 nm, convenient for the product concentration measurement. This is favourable for resolution from other (interfering) hydrazones. Suitable conditions for tryptophan transamination in tissue and enzyme preparations were found. Reaching optimal conditions for tryptophan transamination measurements in vitro is generally limited by low solubility of the amino acid in water solutions: With AST preparation, the velocity of catalysed reaction at 5-50 x 10(-3) M tryptophan concentration was of 1st order to the amino acid substrate. Km for tryptophan was found > or = 2 x 10(-1) M. Therefore the enzyme activity measurement at two different tryptophan concentrations is recommended for unknown samples. Tryptophan transamination by purified pig AST was compared with that catalysed by preparations obtained from mammalian tissues.

Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes.

PubMed

Lieberman, Harris R; Agarwal, Sanjiv; Fulgoni, Victor L

2016-12-01

Tryptophan is an indispensable amino acid and is a precursor of the neurotransmitter serotonin. Tryptophan metabolites, such as serotonin and melatonin, are thought to participate in the regulation of mood and sleep and tryptophan is used to treat insomnia, sleep apnea, and depression. This study examined the intake of tryptophan and its associations with biochemical, behavioral, sleep, and health and safety outcomes in adults in a secondary analysis of a large, publicly available database of the US population. Data from the NHANES 2001-2012 (n = 29,687) were used to determine daily intakes of tryptophan and its associations with biochemical markers of health- and safety-related outcomes, self-reported depression, and sleep-related variables. Data were adjusted for demographic factors and protein intake. Linear trends were computed across deciles of intake for each outcome variable, and P-trends were determined. The usual tryptophan intake by US adults was 826 mg/d, severalfold higher than the Estimated Average Requirement for adults of 4 mg/(kg ⋅ d) (∼280 mg/d for a 70-kg adult). Most health- and safety-related biochemical markers of liver function, kidney function, and carbohydrate metabolism were not significantly (P-trend > 0.05) associated with deciles of tryptophan intake and were well within normal ranges, even for individuals in the 99th percentile of intake. Usual intake deciles of tryptophan were inversely associated with self-reported depression measured by the Patient Health Questionnaire raw score (0-27; P-trend < 0.01) and calculated level (1 = no depression, 5 = severe depression; P-trend < 0.01) and were positively associated with self-reported sleep duration (P-trend = 0.02). Tryptophan intake was not related to most markers of liver function, kidney function or carbohydrate metabolism. Levels of tryptophan intake in the US population appear to be safe as shown by the absence of abnormal laboratory findings. Tryptophan intake was inversely associated with self-reported level of depression and positively associated with sleep duration. © 2016 American Society for Nutrition.

The High-Risk Human Papillomavirus E6 Oncogene Exacerbates the Negative Effect of Tryptophan Starvation on the Development of Chlamydia trachomatis

PubMed Central

Sherchand, Shardulendra P.; Ibana, Joyce A.; Zea, Arnold H.; Quayle, Alison J.; Aiyar, Ashok

2016-01-01

Chlamydia trachomatis is an obligate intracellular pathogen that requires specific essential nutrients from the host cell, one of which is the amino acid tryptophan. In this context interferon gamma (IFNγ) is the major host protective cytokine against chlamydial infections because it induces the expression of the host enzyme, indoleamine 2,3-dioxygenase 1, that degrades tryptophan, thereby restricting bacterial replication. The mechanism by which IFNγ acts has been dissected in vitro using epithelial cell-lines such as HeLa, HEp-2, or the primary-like endocervical cell-line A2EN. All these cell-lines express the high-risk human papillomavirus oncogenes E6 & E7. While screening cell-lines to identify those suitable for C. trachomatis co-infections with other genital pathogens, we unexpectedly found that tryptophan starvation did not completely block chlamydial development in cell-lines that were HR-HPV negative, such as C33A and 293. Therefore, we tested the hypothesis that HR-HPV oncogenes modulate the effect of tryptophan starvation on chlamydial development by comparing chlamydial development in HeLa and C33A cell-lines that were both derived from cervical carcinomas. Our results indicate that during tryptophan depletion, unlike HeLa, C33A cells generate sufficient intracellular tryptophan via proteasomal activity to permit C. trachomatis replication. By generating stable derivatives of C33A that expressed HPV16 E6, E7 or E6 & E7, we found that E6 expression alone was sufficient to convert C33A cells to behave like HeLa during tryptophan starvation. The reduced tryptophan levels in HeLa cells have a biological consequence; akin to the previously described effect of IFNγ, tryptophan starvation protects C. trachomatis from clearance by doxycycline in HeLa but not C33A cells. Curiously, when compared to the known Homo sapiens proteome, the representation of tryptophan in the HR-HPV E6 & E6AP degradome is substantially lower, possibly providing a mechanism that underlies the lowered intracellular free tryptophan levels in E6-expressing cells during starvation. PMID:27658027

Metabolic Availability of the Limiting Amino Acids Lysine and Tryptophan in Cooked White African Cornmeal Assessed in Healthy Young Men Using the Indicator Amino Acid Oxidation Technique.

PubMed

Rafii, Mahroukh; Elango, Rajavel; Ball, Ronald O; Pencharz, Paul B; Courtney-Martin, Glenda

2018-06-01

Maize is a staple food in many regions of the world, particularly in Africa and Latin America. However, maize protein is limiting in the indispensable amino acids lysine and tryptophan, making its protein of poor quality. The main objective of this study was to determine the protein quality of white African cornmeal by determining the metabolic availability (MA) of lysine and tryptophan. To determine the MA of lysine, 4 amounts of l-lysine (10, 13, 16, and 18 mg · kg-1 · d-1 totaling 28.6%, 37.1%, 45.7%, and 51.4% of the mean lysine requirement of 35 mg · kg-1 · d-1, respectively) were studied in 6 healthy young men in a repeated-measures design. To determine the MA of tryptophan, 4 amounts of l-tryptophan (0.5, 1, 1.5, and 2 mg · kg-1 · d-1 totaling 12.5%, 25.0%, 37.5%, and 50.0% of the mean tryptophan requirement of 4 mg · kg-1 · d-1, respectively) were studied in 7 healthy young men in a repeated-measures design. The MAs of lysine and tryptophan were estimated by comparing the indicator amino acid oxidation (IAAO) response with varying intakes of lysine and tryptophan in cooked white cornmeal compared with the IAAO response to l-lysine and l-tryptophan intakes in the reference protein (crystalline amino acid mixture patterned after egg protein) with the use of the slope ratio method. The MAs of lysine and tryptophan from African cooked white cornmeal were 71% and 80%, respectively. Our study provides a robust estimate of the availability of lysine and tryptophan in African white maize to healthy young men. This estimate provides a basis for postproduction fortification or supplementation of maize-based diets. This trial was registered at www.clinicaltrials.gov as NCT02402179.

The Effects of Tryptophan on Everyday Interpersonal Encounters and Social Cognitions in Individuals with a Family History of Depression.

PubMed

Hogenelst, Koen; Schoevers, Robert A; Aan Het Rot, Marije

2015-03-02

Individuals with a family history of depression show subtle abnormalities in the processing of social stimuli. This could negatively affect their interpersonal functioning and contribute to their depression risk. Repeated administration of the serotonin precursor tryptophan has previously been shown to increase agreeable behavior and reduce quarrelsome behavior in irritable people, who are also considered at risk for depression. To examine the effects of tryptophan on social functioning in individuals with a family history of depression, 40 men and women with at least one first-degree relative with depression received tryptophan (1g three times a day) and placebo for 14 days each in a double-blind crossover design and recorded their social behavior and mood during everyday interpersonal encounters. Participants also provided daily ratings of their positive and negative cognitions concerning their social functioning. Tryptophan improved mood. Unexpectedly, tryptophan increased quarrelsome behavior and reduced agreeable behavior, specifically during interactions at home. The behavioral effects of tryptophan were not moderated by mood or by the interaction partner. Negative social cognitions were lower when tryptophan was given second and lower during placebo when placebo was given second. Overall, tryptophan may not alter social behavior in individuals with a family history of depression as it does in irritable people. However, the behavioral effects of tryptophan at home might be seen as a way for individuals with a family history of depression to achieve more control. Over time, this may positively influence the way they feel and think about themselves in a social context. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Relation of plasma tryptophan concentrations during pregnancy to maternal sleep and mental well-being: The GUSTO cohort.

PubMed

van Lee, Linde; Cai, Shirong; Loy, See Ling; Tham, Elaine K H; Yap, Fabian K P; Godfrey, Keith M; Gluckman, Peter D; Shek, Lynette P C; Teoh, Oon Hoe; Goh, Daniel Y T; Tan, Kok Hian; Chong, Yap Seng; Meaney, Michael J; Chen, Helen; Broekman, Birit F P; Chong, Mary F F

2018-01-01

Evidence suggests a relation between plasma tryptophan concentrations and sleep and mental well-being. As no studies have been performed in pregnant women, we studied the relation of plasma tryptophan concentrations during pregnancy with sleep quality, and mood during and after pregnancy. Pregnant women (n = 572) from the Growing Up in Singapore Towards healthy Outcomes study completed the Pittsburgh Sleep Quality Index (PSQI), the Edinburgh Postnatal Depression Scale (EPDS) and the State-Trait Anxiety Inventory (STAI) at 26-28 weeks gestation and three months post-delivery. Plasma tryptophan concentrations were measured at 26-28 weeks gestation. Poisson regressions estimated prevalence ratios (PR) for the association between tryptophan and poor sleep quality (PSQI global score > 5), probable antenatal depression (EPDS ≥ 15) and probable anxiety (STAI-state ≥ 41) were calculated adjusting for covariates. Mean plasma tryptophan concentrations was 48.0µmol/L (SD: 8.09). Higher plasma tryptophan concentrations were associated with a lower prevalence of antenatal poor sleep quality adjusting for covariates [PR: 0.88 (95% CI 0.80, 0.97) per 10µmol/L], especially in those participants who also suffered from anxiety symptoms [PR: 0.80 (95% CI 0.67, 0.95)]. No associations were observed between tryptophan concentrations during pregnancy and postnatal sleep quality or mental well-being. Subjective measures were used to assess sleep and mental well-being. We observed that higher plasma tryptophan concentrations were associated with a 12% lower prevalence of poor sleep quality during pregnancy, in particular among those with anxiety symptoms. These findings suggest the importance of having adequate tryptophan concentrations during pregnancy. Copyright © 2017 Elsevier B.V. All rights reserved.

Dietary tryptophan alleviates dextran sodium sulfate-induced colitis through aryl hydrocarbon receptor in mice.

PubMed

Islam, Jahidul; Sato, Shoko; Watanabe, Kouichi; Watanabe, Takaya; Ardiansyah; Hirahara, Keisuke; Aoyama, Yukihide; Tomita, Shuhei; Aso, Hisashi; Komai, Michio; Shirakawa, Hitoshi

2017-04-01

Ulcerative colitis is the typical progression of chronic inflammatory bowel disease. Amino acids, particularly tryptophan, have been reported to exert a protective effect against colitis induced by dextran sodium sulfate (DSS), but the precise underlying mechanisms remain incompletely clarified. Tryptophan metabolites are recognized to function as endogenous ligands for aryl hydrocarbon receptor (Ahr), which is a critical regulator of inflammation and immunity. Thus, we conducted this study to investigate whether dietary tryptophan supplementation protects against DSS-induced colitis by acting through Ahr. Female wild-type (WT) and Ahr-deficient (knockout; KO) mice (10-12 weeks old) were divided into four groups and fed either a control or 0.5% tryptophan diet. The tryptophan diet ameliorated DSS-induced colitis symptoms and severity in WT mice but not in KO mice, and the diet reduced the mRNA expression of Il-6, Tnfα, Il-1β and the chemokines Ccl2, Cxcl1 and Cxcl2 in the WT groups. Furthermore, Il-22 and Stat3 mRNA expression in the colon was elevated in WT mice fed with the tryptophan diet, which mainly protected epithelial layer integrity, and Ahr also modulated immune homeostasis by regulating Foxp3 and Il-17 mRNA expression. These data suggest that tryptophan-containing diet might ameliorate DSS-induced acute colitis and regulate epithelial homeostasis through Ahr. Thus, tryptophan could serve as a promising preventive agent in the treatment of ulcerative colitis. Copyright © 2017 Elsevier Inc. All rights reserved.

Tryptophan levels, excessive exercise, and nutritional status in anorexia nervosa.

PubMed

Favaro, A; Caregaro, L; Burlina, A B; Santonastaso, P

2000-01-01

It has been hypothesized that reduced dietary availability of tryptophan may be the cause of impaired serotonin activity in underweight anorexics. The study reported here evaluated the relationship between tryptophan availability in the blood and nutritional status in anorexia nervosa. The total amount of tryptophan and the ratio between tryptophan and other large neutral amino acids (TRP/LNAA) were assessed in a sample of 16 starving anorexic patients. Body weight and composition and energy intake were evaluated in all patients. All subjects also completed self-reported questionnaires such as the Hopkins Symptom Checklist and Eating Disorders Inventory (EDI). The TRP/LNAA ratio seems to be higher in patients with a more severe catabolic status. It is, in fact, significantly inversely correlated with body mass index, body fat, muscle mass, daily energy intake, and daily tryptophan intake. The TRP/LNAA ratio also correlates with growth hormone and the EDI drive for thinness. Patients who exercise excessively had significantly higher TRP/LNAA ratios. In starving anorexic patients, the TRP/LNAA ratio does not seem to be determined by the content of tryptophan in the diet, but it correlates with measures of catabolism. The relationship of the TRP/LNAA ratio to excessive exercise and starvation indicates the importance of further investigations exploring the role of tryptophan availability in maintaining anorexia nervosa.

Phosphorescence/microwave double-resonance spectra of tryptophan perturbed by methylmercury(II).

PubMed Central

Davis, J M; Maki, A H

1982-01-01

Amplitude-modulated phosphorescence/microwave double-resonance (AM-PMDR) spectra are reported for complexes of methylmercury(II) cation, designated CH3Hg(II), with tryptophan and glyceraldehyde-3-phosphate dehydrogenase (GPDHase; from rabbit muscle). Wavelength shifts are observed in the AM-PMDR spectra of CH3Hg(II)-tryptophan, which are obtained by microwave pumping in distinct zero-field D + E magnetic resonance transitions, demonstrating that AM-PMDR can be used to display selectively the phosphorescence spectra of structurally distinct complexes with different zero-field splittings. The AM-PMDR spectra accurately represent the phosphorescence of CH3Hg(II)-tryptophan. Binding of CH3Hg(II) to a cysteine site of GDPHase perturbs the luminescence of one of the two optically resolved tryptophan. The AM-PMDR spectrum of the perturbed tryptophan is obtained by microwave pumping of the D + E magnetic resonance signal, which can be observed optically only in the presence of a heavy atom perturbation. The resulting spectrum is broadened and shifted to the blue relative to the corresponding tryptophan phosphorescence spectrum of the uncomplexed enzyme. Comparison of the AM-PMDR spectra of CH3Hg(II)-tryptophan and CH3Hg(II)-GPDHase suggests that there are differences in the mechanisms of heavy atom perturbation in these complexes. PMID:6956860

The role of adrenal hormones in the activation of tryptophan 2,3-dioxygenase by nicotinic acid in rat liver.

PubMed

Sainio, E L

1997-09-01

In this study, our previous finding that nicotinic acid activates tryptophan 2,3-dioxygenase as strongly as tryptophan was investigated in further detail. This study focused on the role of the adrenals in the activation process. Adrenalectomy abolished the activation due to nicotinic acid, but not the activation caused by tryptophan. The role of corticoids and/or adrenomedullary hormones in the enzyme activation was studied, by supplementing these hormones in adrenalectomized rats using minipumps implanted under the skin. The results showed that the enhanced activity of tryptophan 2,3-dioxygenase caused by nicotinic acid was partly restored by adrenaline following adrenalectomy but not by corticosterone supplementation. The results were supported by further experiments in which the rats were treated with adrenaline or corticosterone intraperitoneally before nicotinic acid administration. The conclusion that adrenaline participates in the regulation of tryptophan 2,3-dioxygenase should promote further study to determine whether adrenaline is a general modulator of this enzyme. This experimental model generated new information on the activation mechanism of tryptophan 2,3-dioxygenase by nicotinic acid.

Targeting Tryptophan Catabolism: A Novel Method to Block Triple-Negative Breast Cancer Metastasis

DTIC Science & Technology

2017-04-01

AWARD NUMBER: W81XWH-15-1-0039 TITLE: Targeting Tryptophan Catabolism: A Novel Method to Block Triple- Negative Breast Cancer Metastasis...Mar 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Targeting Tryptophan Catabolism: A Novel Method to Block Triple-Negative Breast Cancer...Tryptophan Catabolism: A Novel Method to Block Triple-Negative Breast Cancer Metastasis,” Submitted by Jennifer K. Richer, PhD, University of Colorado

L-Tryptophan: Effects on Daytime Sleep Latency and the Waking EEG

DTIC Science & Technology

1982-10-22

TRYPTOPHAN: EFFECTS ON DAYTIME SLEEP LATENCY AND THE WAKING EEG pr Cheryl L. Slinweber, Reidun Ursin, 1 Raymond P. Hilbert and Richard L. Hilderbrand 2 p...Gessa, 1973; Curzon & Knott , 1974; Gessa & Tagliamonte, 1974), and it has been previously suggested that 1-tryptophan may have hyp- notic effects...Curzon, G. & Knott , P.J. Fatty acids in the disposition of tryptophan. In: Aromatic Amino Acids in the Brain, Ciba Foundation Symposium 22, Elsevier

Effect of dietary supplementation of l-tryptophan on thermal tolerance and oxygen consumption rate in Cirrhinus mrigala fingerlings under varied stocking density.

PubMed

Tejpal, C S; Sumitha, E B; Pal, A K; Shivananda Murthy, H; Sahu, N P; Siddaiah, G M

2014-04-01

A 60 day feeding trial was conducted to study the effect of dietary l-tryptophan on thermal tolerance and oxygen consumption rate of freshwater fish, mrigala, Cirrhinus mrigala reared under ambient temperature at low and high stocking density. Four hundred eighty fingerlings were distributed into eight experimental groups. Four groups each of low density group (10 fishes/75L water) and higher density group (30 fishes/75L water) were fed a diet containing 0, 0.68, 1.36 or 2.72% l-tryptophan in the diet, thus forming eight experimental groups namely, Low density control (LC) (basal feed +0% l-tryptophan); LT1 (basal feed+0.68% l-tryptophan); LT2 (basal feed+1.36% l-tryptophan); LT3 (basal feed+2.72% l-tryptophan); high density control (HC) (basal feed+0% l-tryptophan); HT1 (basal feed+0.68% l-tryptophan); HT2 (basal feed+1.36% l-tryptophan); and HT3 (basal feed+2.72% l-tryptophan) were fed at 3% of the body weight. The test diets having crude protein 34.33±0.23 to 35.81±0.18% and lipid 423.49±1.76 to 425.85±0.31KCal/100g were prepared using purified ingredients. The possible role of dietary l-tryptophan on thermal tolerance and oxygen consumption rate was assessed in terms of critical thermal maxima (CTMax), critical thermal minima (CTMin), lethal thermal maxima (LTMax) and lethal thermal minima (LTMin). The CTMax, CTMin, LTMax and LTMin values were found to be significantly higher (p<0.05) in the treatment groups with CTMax 42.94±0.037 (LT2); LT Max 43.18±0.070 (LT2); CTMin 10.47±0.088 (LT2) and LTMin 9.42±0.062 (LT3), whereas the control group showed a lower tolerance level. The same trend was observed in the high density group (CTMax 42.09±0.066 (LT3); LTMax 43 23±0.067 (HT3); CTMin 10.98±0.040 (HT3) and LTMin 9.74±0.037 (HT3). However, gradual supplementation of dietary l-tryptophan in the diet significantly reduced the oxygen consumption rate in both the low density group (Y=-26.74x+222.4, r²=0.915) and the high density group (Y=-32.96x+296.5, r²=0.8923). Dietary supplementation of l-tryptophan at a level of 1.36% improved the thermal tolerance level and reduced the oxygen consumption rate in C. mrigala fingerlings. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Acute tryptophan depletion in eating disorders].

PubMed

Díaz-Marsa, M; Lozano, C; Herranz, A S; Asensio-Vegas, M J; Martín, O; Revert, L; Saiz-Ruiz, J; Carrasco, J L

2006-01-01

This work describes the rational bases justifying the use of acute tryptophan depletion technique in eating disorders (ED) and the methods and design used in our studies. Tryptophan depletion technique has been described and used in previous studies safely and makes it possible to evaluate the brain serotonin activity. Therefore it is used in the investigation of hypotheses on serotonergic deficiency in eating disorders. Furthermore, and given the relationship of the dysfunctions of serotonin activity with impulsive symptoms, the technique may be useful in biological differentiation of different subtypes, that is restrictive and bulimic, of ED. 57 female patients with DSM-IV eating disorders and 20 female controls were investigated with the tryptophan depletion test. A tryptophan-free amino acid solution was administered orally after a two-day low tryptophan diet to patients and controls. Free plasma tryptophan was measured at two and five hours following administration of the drink. Eating and emotional responses were measured with specific scales for five hours following the depletion. A study of the basic characteristics of the personality and impulsivity traits was also done. Relationship of the response to the test with the different clinical subtypes and with the temperamental and impulsive characteristics of the patients was studied. The test was effective in considerably reducing plasma tryptophan in five hours from baseline levels (76%) in the global sample. The test was well tolerated and no severe adverse effects were reported. Two patients withdrew from the test due to gastric intolerance. The tryptophan depletion test could be of value to study involvement of serotonin deficits in the symptomatology and pathophysiology of eating disorders.

Tryptophan depletion disinhibits punishment but not reward prediction: implications for resilience.

PubMed

Robinson, Oliver J; Cools, Roshan; Sahakian, Barbara J

2012-01-01

We have previously shown that tryptophan depletion enhances punishment but not reward prediction (Cools et al. in Neuropsychopharmacology 33:2291-2299, 2008b). This provided evidence for a valence-specific role of serotonin (which declines under depleted tryptophan) in aversive processing. Recent theoretical (Dayan and Huys in PLoS Comput Biol 4:e4, 2008) and experimental (Crockett et al. in J Neurosci 29:11993-11999, 2009) approaches have, however, further specified this role by showing that serotonin is critical for punishment-induced inhibition. We sought to examine the role of serotonin in punishment-induced inhibition. We also examined the impact of induced mood on this effect to assess whether effects of tryptophan depletion on affective inhibition are moderated by mood. Healthy females consumed a balanced amino acid mixture with (N = 20) or without (N = 21) the serotonin precursor tryptophan. Each subject completed either negative or neutral mood induction. All subjects completed the reward and punishment reversal learning task adopted in the previous study. We demonstrate a punishment prediction impairment in individuals who consumed tryptophan which was absent in individuals who were depleted of tryptophan. This effect was impervious to mood state. Our results suggest that serotonin promotes the inhibition of responses to punishing outcomes. This may lead to reduced punishment prediction accuracy in the presence of tryptophan and may contribute to resilience to affective disorders. Reduction of serotonin via tryptophan depletion then removes this inhibition. As such, we highlight a mechanism by which reduced serotonin can contribute to disorders of impulsivity and compulsivity as well as disorders of emotion.

Tryptophan availability modulates serotonin release from rat hypothalamic slices

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1989-01-01

The relationship between the tryptophan availability and serononin release from rat hypothalamus was investigated using a new in vitro technique for estimating rates at which endogenous serotonin is released spontaneously or upon electrical depolarization from hypothalamic slices superfused with a solution containing various amounts of tryptophan. It was found that the spontaneous, as well as electrically induced, release of serotonin from the brain slices exhibited a dose-dependent relationship with the tryptophan concentration of the superfusion medium.

Enhancement of stability of L-tryptophan dehydrogenase from Nostoc punctiforme ATCC29133 and its application to L-tryptophan assay.

PubMed

Matsui, Daisuke; Okazaki, Seiji; Matsuda, Motoki; Asano, Yasuhisa

2015-02-20

Microbial NAD(+)-dependent L-tryptophan dehydrogenase (TrpDH, EC1.4.1.19), which catalyzes the reversible oxidative deamination and the reductive amination between L-tryptophan and indole-3-pyruvic acid, was found in the scytonemin biosynthetic pathway of Nostoc punctiforme ATCC29133. The TrpDH exhibited high specificity toward L-tryptophan, but its instability was a drawback for L-tryptophan determination. The mutant enzyme TrpDH L59F/D168G/A234D/I296N with thermal stability was obtained by screening of Escherichia coli transformants harboring various mutant genes, which were generated by error-prone PCR using complementation in an L-tryptophan auxotroph of E. coli. The specific activity and stability of this mutant enzyme were higher than those of the wild type enzyme. We also revealed here that in these four mutation points, the two amino acid residues Asp168 and Ile296 contributed to increase the enzyme stability, and the Leu59, Ala234 residues to increase its specific activity. Growth of the strain harboring the gene of above 4 point mutated enzyme was accelerated by the enhanced performance. In the present study, we demonstrated that TrpDH L59F/D168G/A234D/I296N was available for determination of L-tryptophan in human plasma. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluorescence kinetics of Trp-Trp dipeptide and its derivatives in water via ultrafast fluorescence spectroscopy.

PubMed

Jia, Menghui; Yi, Hua; Chang, Mengfang; Cao, Xiaodan; Li, Lei; Zhou, Zhongneng; Pan, Haifeng; Chen, Yan; Zhang, Sanjun; Xu, Jianhua

2015-08-01

Ultrafast fluorescence dynamics of Tryptophan-Tryptophan (Trp-Trp/Trp2) dipeptide and its derivatives in water have been investigated using a picosecond resolved time correlated single photon counting (TCSPC) apparatus together with a femtosecond resolved upconversion spectrophotofluorometer. The fluorescence decay profiles at multiple wavelengths were fitted by a global analysis technique. Nanosecond fluorescence kinetics of Trp2, N-tert-butyl carbonyl oxygen-N'-aldehyde group-l-tryptophan-l-tryptophan (NBTrp2), l-tryptophan-l-tryptophan methyl ester (Trp2Me), and N-acetyl-l-tryptophan-l-tryptophan methyl ester (NATrp2Me) exhibit multi-exponential decays with the average lifetimes of 1.99, 3.04, 0.72 and 1.22ns, respectively. Due to the intramolecular interaction between two Trp residues, the "water relaxation" lifetime was observed around 4ps, and it is noticed that Trp2 and its derivatives also exhibit a new decay with a lifetime of ∼100ps, while single-Trp fluorescence decay in dipeptides/proteins shows 20-30ps. The intramolecular interaction lifetime constants of Trp2, NBTrp2, Trp2Me and NATrp2Me were then calculated to be 3.64, 0.93, 11.52 and 2.40ns, respectively. Candidate mechanisms (including heterogeneity, solvent relaxation, quasi static self-quenching or ET/PT quenching) have been discussed. Copyright © 2015. Published by Elsevier B.V.

In Vivo Function of Tryptophans in the Arabidopsis UV-B Photoreceptor UVR8[W

PubMed Central

O’Hara, Andrew; Jenkins, Gareth I.

2012-01-01

Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor specifically for UV-B light that initiates photomorphogenic responses in plants. UV-B exposure causes rapid conversion of UVR8 from dimer to monomer, accumulation in the nucleus, and interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), which functions with UVR8 in UV-B responses. Studies in yeast and with purified UVR8 implicate several tryptophan amino acids in UV-B photoreception. However, their roles in UV-B responses in plants, and the functional significance of all 14 UVR8 tryptophans, are not known. Here we report the functions of the UVR8 tryptophans in vivo. Three tryptophans in the β-propeller core are important in maintaining structural stability and function of UVR8. However, mutation of three other core tryptophans and four at the dimeric interface has no apparent effect on function in vivo. Mutation of three tryptophans implicated in UV-B photoreception, W233, W285, and W337, impairs photomorphogenic responses to different extents. W285 is essential for UVR8 function in plants, whereas W233 is important but not essential for function, and W337 has a lesser role. Ala mutants of these tryptophans appear monomeric and constitutively bind COP1 in plants, but their responses indicate that monomer formation and COP1 binding are not sufficient for UVR8 function. PMID:23012433

Thirteen week toxicity study of dietary l-tryptophan in rats with a recovery period of 5 weeks.

PubMed

Shibui, Yusuke; Matsumoto, Hideki; Masuzawa, Yoko; Ohishi, Takumi; Fukuwatari, Tsutomu; Shibata, Katsumi; Sakai, Ryosei

2018-04-01

Although l-tryptophan is nutritionally important and widely used in medical applications, toxicity data for its oral administration are limited. The purpose of this study was to evaluate the potential toxicity of an experimental diet containing added l-tryptophan at doses of 0 (basal diet), 1.25%, 2.5% and 5.0% when administered to Sprague-Dawley rats for 13 weeks. There were no toxicological changes in clinical signs, ophthalmology, urinalysis, hematology, necropsy, organ weight and histopathology between control rats and those fed additional l-tryptophan. Body weight gain and food consumption significantly decreased throughout the administration period in males in the 2.5% group and in both sexes in the 5.0% group. At the end of the dosing period, decreases in water intake in males in the 5.0% group and in serum glucose in females in the 5.0% group were observed. The changes described above were considered toxicologically significant; however, they were not observed after a 5 week recovery period, suggesting reversibility. Consequently, the no-observed-adverse-effect level of l-tryptophan in the present study was 1.25% for males and 2.5% for females (mean intake of l-tryptophan: 779 mg kg -1 body weight day -1 [males] and 1765 mg kg -1 body weight day -1 [females]). As the basal diet used in this study contained 0.27% of proteinaceous l-tryptophan, the no-observed-adverse-effect level of overall l-tryptophan was 1.52% for males and 2.77% for females (mean intake of overall l-tryptophan: 948 mg kg -1 body weight day -1 (males) and 1956 mg kg -1 body weight day -1 (females)). We conclude that l-tryptophan has a low toxicity profile in terms of human use. Copyright © 2017 John Wiley & Sons, Ltd.

π-Cation interactions as the origin of the weak absorption at 532 nm observed in tryptophan-containing polypeptides.

PubMed

Roveri, O A; Braslavsky, S E

2012-06-01

We have previously reported that bovine serum albumin (BSA) and other proteins that do not contain prosthetic groups exhibited a weak light absorption in the visible, only detectable by pulsed laser-induced optoacoustic spectroscopy (LIOAS). Human serum albumin (HSA) exhibited signals 25% higher than those observed with BSA. Signals comparable to those obtained with BSA were observed with poly(L-Trp, L-Lys), poly(L-Trp, L-Arg) or poly(L-Trp, L-Orn) at pH 7.0. No signals were obtained when tryptophan was replaced by other amino acids or when free tryptophan or the tripeptide Lys-Trp-Lys was assayed (pH 7.0). Tryptophan in HCl 5 N produced LIOAS signals similar to those produced by tryptophan-containing copolymers. Moreover, the absorption peak could be observed in a UV-VIS spectrophotometer. Therefore, the LIOAS signals obtained with BSA, HSA, and tryptophan-containing random copolymers may be attributed to a new transition of the indole moiety of their tryptophan residues when "protonated". Tryptophan residues of proteins are known to participate in π-cation interactions, which are important in protein stability and function. As a matter of fact, HSA and BSA contain an internal tryptophan in close proximity to lysine and arginine residues and therefore suitable for π-cation interactions. The strength of this type of interaction strongly depends on distances and relative orientations of both amino acid residues. Accordingly, these interactions should be highly sensitive to conformational changes. Based on preliminary results that have shown that LIOAS signal at 532 nm depended on the aggregation state of BSA and/or on the oxidation state of its Cys-34, we postulate that the LIOAS signal observed with proteins and tryptophan-containing polypeptides are related to Trp-Lys or Trp-Arg interactions and that the intensity of the signal depends on the strength of such interactions.

Alzheimer's disease evaluation using label-free, stainless, fluorescence to measure tryptophan metabolism along the kynurenine pathway

NASA Astrophysics Data System (ADS)

Sordillo, Laura A.; Zhang, Lin; Shi, Lingyan; Sriramoju, Vidyasagar; Sordillo, Peter P.; Alfano, Robert R.

2018-02-01

Under stress conditions, pro-inflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1 beta, interleukin 6 and interferon gamma are released. It is known that these cytokines stimulate indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO), which increase tryptophan metabolism through the kynurenine pathway, and that this can cause increased production of neurotoxic compounds. Brain tissues from Alzheimer's disease patients and agematched controls were investigated using label-free fluorescence spectroscopy. Tryptophan (exc. 280/ em. 340 nm) and its metabolites (N-formyl-L-kynurenine (exc. 325/em. 434 nm), kynurenine (exc. 365/em. 480 nm) and kynurenic acid (exc. 330/em. 390 nm)) have distinct spectral profiles. Preliminary results show a difference in the optical signatures in three important areas of the brain (hippocampus, BA 9, BA 17) between patients with Alzheimer's disease and agedmatched controls (normal), and a marked relative increase in tryptophan in the Alzheimer's patients. Thus determinations of tryptophan to tryptophan metabolite ratios could potentially be used to measure IDO and TDO activity and the degree of inflammation in the brain. This label-free optical technique may be useful in the study of Alzheimer's and other neurodegenerative diseases.

A molecularly imprinted polymer-coated CdTe quantum dot nanocomposite for tryptophan recognition based on the Förster resonance energy transfer process

NASA Astrophysics Data System (ADS)

Tirado-Guizar, Antonio; Paraguay-Delgado, Francisco; Pina-Luis, Georgina E.

2016-12-01

A new ‘turn-on’ Förster resonance energy transfer (FRET) nanosensor for l-tryptophan based on molecularly imprinted quantum dots (QDs) is proposed. The approach combines the advantages of the molecular imprinting technique, the fluorescent characteristics of the QDs and the energy transfer process. Silica-coated CdTe QDs were first synthesized and then molecularly imprinted using a sol-gel process without surfactants. The final composite presents stable fluorescence which increases with the addition of l-tryptophan. This ‘turn-on’ response is due to a FRET mechanism from the l-tryptophan as donor to the imprinted QD as acceptor. QDs are rarely applied as acceptors in FRET systems. The nanosensor shows selectivity towards l-tryptophan in the presence of other amino acids and interfering ions. The l-tryptophan nanosensor exhibits a linear range between 0 and 8 µM concentration, a detection limit of 350 nM and high selectivity. The proposed sensor was successfully applied for the detection of l-tryptophan in saliva. This novel sensor may offer an alternative approach to the design of a new generation of imprinted nanomaterials for the recognition of different analytes.

l-Tryptophan Radical Cation Electron Spin Resonance Studies: Connecting Solution-derived Hyperfine Coupling Constants with Protein Spectral Interpretations

PubMed Central

Connor, Henry D.; Sturgeon, Bradley E.; Mottley, Carolyn; Sipe, Herbert J.; Mason, Ronald P.

2009-01-01

Fast-flow electron spin resonance (ESR) spectroscopy has been used to detect a free radical formed from the reaction of l-tryptophan with Ce4+ in an acidic aqueous environment. Computer simulations of the ESR spectra from l-tryptophan and several isotopically modified forms strongly support the conclusion that the l-tryptophan radical cation has been detected by ESR for the first time. The hyperfine coupling constants (HFCs) determined from the well-resolved isotropic ESR spectra support experimental and computational efforts to understand l-tryptophan's role in protein catalysis of oxidation-reduction processes. l-tryptophan HFCs facilitated the simulation of fast-flow ESR spectra of free radicals from two related compounds, tryptamine and 3-methylindole. Analysis of these three compounds' β-methylene hydrogen HFC data along with equivalent l-tyrosine data has led to a new computational method that can distinguish between these two amino acid free radicals in proteins without dependence on isotope labeling, electron nuclear double resonance or high-field ESR. This approach also produces geometric parameters (dihedral angles for the β-methylene hydrogens) which should facilitate protein site assignment of observed l-tryptophan radicals as has been done for l-tyrosine radicals. PMID:18433127

Effects of tryptophan derivatives and β-carboline alkaloids on radiation- and peroxide-induced transformations of ethanol

NASA Astrophysics Data System (ADS)

Sverdlov, R. L.; Brinkevich, S. D.; Shadyro, O. I.

2014-05-01

The subject of this study was investigation of interactions of tryptophan and its derivatives, including structurally related β-carboline alkaloids with oxygen- and carbon-centered radicals being formed during radiation- and peroxide-induced transformations of ethanol. It was shown that the above named compounds suppressed recombination and disproportionation reactions of α-hydroxyethyl radicals. The inhibitory effects of tryptophan, 5-hydroxytryptophan and serotonin were mainly realized by means of reduction and addition reactions, while those of β-carboline alkaloids - harmine, harmane and harmaline - were due to oxidation reactions. Melatonin displayed low reactivity towards α-hydroxyethyl radicals. Tryptophan derivatives and β-carboline alkaloids were found to inhibit radiation-induced oxidation of ethanol while being virtually not used up. The low transformation yields of tryptophan, 5-hydroxytryptophan and serotonin, as well as β-carboline alkaloids, indicate their capability of regeneration, which could occur on interaction of tryptophan with О-2 and НО2, or on oxidation of α-hydroxyethyl radicals by β-carboline alkaloids.

Effects of water-alcohol binary solvents on the thermochemical characteristics of L-tryptophane dissolution at 298.15 K

NASA Astrophysics Data System (ADS)

Badelin, V. G.; Smirnov, V. I.

2013-01-01

The enthalpies of L-tryptophane solution in water-methanol, water-ethanol, water-1-propanol, and water-2-propanol mixtures at alcohol concentrations of x 2 = 0-0.4 mole fractions were measured by calorimetry. The standard enthalpies of L-tryptophane solution (Δsol H ∘) and transfer (Δtr H ∘) from water to the binary solvent were calculated. The influence of the composition of the water-alcohol mixture and the structure and properties of L-tryptophane on the enthalpy characteristics of the latter was considered. The enthalpy coefficients of pair interactions ( h xy ) of L-tryptophane with alcohol molecules were calculated. The coefficients were positive and increased in the series: methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), and 2-propanol (2-PrOH). The solution and transfer enthalpies of L-tryptophane were compared with those of aliphatic amino acids (glycine, L-threonine, DL-alanine, L-valine, and L-phenylalanine) in similar binary solvents.

N-acetyl-L-tryptophan, a substance-P receptor antagonist attenuates aluminum-induced spatial memory deficit in rats.

PubMed

Fernandes, Joylee; Mudgal, Jayesh; Rao, Chamallamudi Mallikarjuna; Arora, Devinder; Basu Mallik, Sanchari; Pai, K S R; Nampoothiri, Madhavan

2018-06-01

Neuroinflammation plays an important role in the pathophysiology of Alzheimer's disease. Neurokinin substance P is a key mediator which modulates neuroinflammation through neurokinin receptor. Involvement of substance P in Alzheimer's disease is still plausible and various controversies exist in this hypothesis. Preventing the deleterious effects of substance P using N-acetyl-L-tryptophan, a substance P antagonist could be a promising therapeutic strategy. This study was aimed to evaluate the effect of N-acetyl-L-tryptophan on aluminum induced spatial memory alterations in rats. Memory impairment was induced using aluminum chloride (AlCl 3 ) at a dose of 10 mg/kg for 42 d. After induction of dementia, rats were exposed to 30 and 50 mg/kg of N-acetyl-L-tryptophan for 28 d. Spatial memory alterations were measured using Morris water maze. Acetylcholinesterase activity and antioxidant enzyme glutathione level were assessed in hippocampus, frontal cortex and striatum. The higher dose of N-acetyl-L-tryptophan (50 mg/kg) significantly improved the aluminum induced memory alterations. N-acetyl-L-tryptophan exposure resulted in significant increase in acetylcholinesterase activity and glutathione level in hippocampus. The neuroprotective effect of N-acetyl-L-tryptophan could be due to its ability to block substance P mediated neuroinflammation, reduction in oxidative stress and anti-apoptotic properties. To conclude, N-acetyl-L-tryptophan may be considered as a novel neuroprotective therapy in Alzheimer's disease.

Role for tryptophan in regulation of protein synthesis in porcine muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, F.D.; Smith, T.K.; Bayley, H.S.

1988-04-01

Experiments were conducted to determine the effect of varying concentrations of dietary tryptophan on growth rate and protein synthesis in edible muscle tissues of growing swine. A total of 45 immature swine (initial weight approximately 24 kg) were fed corn-gelatin diets containing 0.5 (n = 8), 0.8 (n = 10), 1.3 (n = 10), 1.5 (n = 7) or 2.0 (n = 10) g tryptophan/kg diet for 35 d. Animals fed 0.5 and 0.8 g tryptophan/kg grew more slowly, consumed less feed and had a lower efficiency of feed utilization than animals fed higher concentrations of tryptophan. Thirty similar animalsmore » were used in a second experiment. Diets containing 0.5, 0.8, 1.0, 1.5 or 2.0 g tryptophan/kg diet (n = 6) were fed for 14 d, after which all animals were killed and samples were taken of longissimus dorsi, triceps brachii and biceps femoris. Protein synthetic activity was determined by monitoring the incorporation of (/sup 14/C)phenylalanine into protein in vitro. There was no significant difference in synthetic activity between different muscle types. There was no effect of diet on the activity of the muscle soluble protein fraction. The activity of the muscle ribosomal fraction, however, was positively correlated with increasing concentrations of dietary tryptophan. It was concluded that tryptophan has the potential to regulate muscle protein synthesis in a manner beyond serving simply as a component of protein.« less

Acute tryptophan pretreatment protects against behavioral changes caused by cerebral ischemia.

PubMed

Carney, J M

1986-05-15

Male gerbils (Meronies ungulata) were treated with various doses of tryptophan and the changes in spontaneous motor activity determined. Tryptophan decreased behavior at a dose of 200 mg/kg. Cerebral ischemia was produced by bilateral carotid occlusion for 5 min. This duration of ischemia produced a large increase in activity at both 6 h and 24 h postischemia. Tryptophan (200 mg/kg) prevented the ischemia-induced increases in locomotor activity. These data suggest that dietary amino acids may play a role in determining the effects of ischemia.

Resonant Raman spectra of grades of human brain glioma tumors reveal the content of tryptophan by the 1588 cm-1 mode

NASA Astrophysics Data System (ADS)

Zhou, Yan; Liu, Cheng-hui; Zhou, Lixin; Zhu, Ke; Liu, Yulong; Zhang, Lin; Boydston-White, Susie; Cheng, Gangge; Pu, Yang; Bidyut, Das; Alfano, Robert R.

2015-03-01

RR spectra of brain normal tissue, gliomas in low grade I and II, and malignant glioma tumors in grade III and IV were measured using a confocal micro Raman spectrometer. This report focus on the relative contents of tryptophan (W) in various grades of brain glioma tumors by the intrinsic molecular resonance Raman (RR) spectroscopy method using the 1588cm-1 of tryptophan mode by 532 nm excitation. The RR spectra of key fingerprints of tryptophan, with a main vibrational mode at 1588cm-1 (W8b), were observed. It was found that tryptophan contribution was accumulated in grade I to IV gliomas and the mode of 1588cm-1 in grade III and IV malignant gliomas were enhanced by resonance.

Gonadal hormone levels and platelet tryptophan and serotonin concentrations in perimenopausal women with or without depressive symptoms.

PubMed

Flores-Ramos, Mónica; Moreno, Julia; Heinze, Gerhard; Aguilera-Pérez, Rafael; Pellicer Graham, Francisco

2014-03-01

The etiology of depressive symptoms associated with the transition to menopause is still unknown; hormonal changes, serotonergic system or insomnia, could be a trigger to depressive symptomatology. The aim of the present study was to evaluate gonadal hormonal levels, platelet serotonin concentrations and platelet tryptophan concentrations in a group of depressed perimenopausal women and their healthy counterparts. A total of 63 perimenopausal women between 45 and 55 years old were evaluated; of these, 44 were depressed patients, and 19 were perimenopausal women without depression. The instruments that were applied included the Center for Epidemiologic Studies Depression Scale (CES-D), the Hamilton Depression Rating Scale (HDRS) and the Green Climacteric Scale (GCS); gonadal hormone levels and platelet tryptophan and serotonin concentrations were measured in all participants. Differences in hormonal levels and tryptophan and serotonin concentrations were evaluated with respect to specific symptoms, such as insomnia, hot flashes, nervousness, depressed mood and loss of interest. No differences between groups were observed with respect to hormonal levels and tryptophan and serotonin concentrations; mean sleep hours and insomnia were significantly correlated with platelet tryptophan concentrations. In this sample, all symptoms of depression could not be explained by platelet tryptophan and serotonin concentrations and hormonal levels; differences were observed only when we evaluated insomnia and hot flashes.

5-Fluoroindole Resistance Identifies Tryptophan Synthase Beta Subunit Mutants in Arabidopsis Thaliana

PubMed Central

Barczak, A. J.; Zhao, J.; Pruitt, K. D.; Last, R. L.

1995-01-01

A study of the biochemical genetics of the Arabidopsis thaliana tryptophan synthase beta subunit was initiated by characterization of mutants resistant to the inhibitor 5-fluoroindole. Thirteen recessive mutations were recovered that are allelic to trp2-1, a mutation in the more highly expressed of duplicate tryptophan synthase beta subunit genes (TSB1). Ten of these mutations (trp2-2 through trp2-11) cause a tryptophan requirement (auxotrophs), whereas three (trp2-100 through trp2-102) remain tryptophan prototrophs. The mutations cause a variety of changes in tryptophan synthase beta expression. For example, two mutations (trp2-5 and trp2-8) cause dramatically reduced accumulation of TSB mRNA and immunologically detectable protein, whereas trp2-10 is associated with increased mRNA and protein. A correlation exists between the quantity of mutant beta and wild-type alpha subunit levels in the trp2 mutant plants, suggesting that the synthesis of these proteins is coordinated or that the quantity or structure of the beta subunit influences the stability of the alpha protein. The level of immunologically detectable anthranilate synthase alpha subunit protein is increased in the trp2 mutants, suggesting the possibility of regulation of anthranilate synthase levels in response to tryptophan limitation. PMID:7635295

Tryptophan metabolism, its relation to inflammation and stress markers and association with psychological and cognitive functioning: Tasmanian Chronic Kidney Disease pilot study.

PubMed

Karu, Naama; McKercher, Charlotte; Nichols, David S; Davies, Noel; Shellie, Robert A; Hilder, Emily F; Jose, Matthew D

2016-11-10

Adults with chronic kidney disease (CKD) exhibit alterations in tryptophan metabolism, mainly via the kynurenine pathway, due to higher enzymatic activity induced mainly by inflammation. Indoles produced by gut-microflora are another group of tryptophan metabolites related to inflammation and conditions accompanying CKD. Disruptions in tryptophan metabolism have been associated with various neurological and psychological disorders. A high proportion of CKD patients self-report symptoms of depression and/or anxiety and decline in cognitive functioning. This pilot study examines tryptophan metabolism in CKD and explores associations with psychological and cognitive functioning. Twenty-seven adults with CKD were part of 49 patients recruited to participate in a prospective pilot study, initially with an eGFR of 15-29 mL/min/1.73 m 2 . Only participants with viable blood samples and complete psychological/cognitive data at a 2-year follow-up were included in the reported cross-sectional study. Serum samples were analysed by Liquid Chromatography coupled to Mass Spectrometry, for tryptophan, ten of its metabolites, the inflammation marker neopterin and the hypothalamic-pituitary-adrenal (HPA) axis marker cortisol. The tryptophan breakdown index (kynurenine / tryptophan) correlated with neopterin (Pearson R = 0.51 P = 0.006) but not with cortisol. Neopterin levels also correlated with indoxyl sulfate (R = 0.68, P < 0.0001) and 5 metabolites of tryptophan (R range 0.5-0.7, all P ≤ 0.01), which were all negatively related to eGFR (P < 0.05). Higher levels of kynurenic acid were associated with lower cognitive functioning (Spearman R = -0.39, P < 0.05), while indole-3 acetic acid (IAA) was correlated with anxiety and depression (R = 0.52 and P = 0.005, R = 0.39 and P < 0.05, respectively). The results of this preliminary study suggest the involvement of inflammation in tryptophan breakdown via the kynurenine pathway, yet without sparing tryptophan metabolism through the 5-HT (serotonin) pathway in CKD patients. The multiple moderate associations between indole-3 acetic acid and psychological measures were a novel finding. The presented pilot data necessitate further exploration of these associations within a large prospective cohort to assess the broader significance of these findings.

Plasma L-tryptophan concentration in major depressive disorder: new data and meta-analysis.

PubMed

Ogawa, Shintaro; Fujii, Takashi; Koga, Norie; Hori, Hiroaki; Teraishi, Toshiya; Hattori, Kotaro; Noda, Takamasa; Higuchi, Teruhiko; Motohashi, Nobutaka; Kunugi, Hiroshi

2014-09-01

Tryptophan, an essential amino acid, is the precursor to serotonin and is metabolized mainly by the kynurenine pathway. Both serotonin and kynurenine have been implicated in the pathophysiology of major depressive disorder (MDD). However, plasma tryptophan concentration in patients with MDD has not unequivocally been reported to be decreased, which prompted us to perform a meta-analysis on previous studies and our own data. We searched the PubMed database for case-control studies published until August 31, 2013, using the search terms plasma AND tryptophan AND synonyms for MDD. An additional search was performed for the term amino acid instead of tryptophan. We obtained our own data in 66 patients with MDD (DSM-IV) and 82 controls who were recruited from March 2011 to July 2012. The majority of the patients were medicated (N = 53). Total plasma tryptophan concentrations were measured by the liquid chromatography/mass spectrometry method. We scrutinized 160 studies for eligibility. Original articles that were written in English and documented plasma tryptophan values in patients and controls were selected. We included 24 studies from the literature and our own data in the meta-analysis, which involved a total of 744 patients and 793 controls. Data on unmedicated patients (N = 156) and their comparison subjects (N = 203) were also extracted. To see the possible correlation between tryptophan concentrations and depression severity, meta-regression analysis was performed for 10 studies with the Hamilton Depression Rating Scale 17-item version score. In our case-control study, mean (SD) plasma tryptophan level was significantly decreased in the MDD patients versus the controls (53.9 [10.9] vs 57.2 [11.3] μmol/L; P = .03). The meta-analysis after adjusting for publication bias showed a significant decrease in patients with MDD with a modest effect size (Hedges g, -0.45). However, analysis on unmedicated subjects yielded a large effect (Hedges g, -0.84; P = .00015). We found a weak association with depression severity in the meta-regression analysis (P = .049). This meta-analysis provides convincing evidence for reduced plasma tryptophan levels in patients with MDD, particularly in unmedicated patients. © Copyright 2014 Physicians Postgraduate Press, Inc.

Psychosocial stress and inflammation driving tryptophan breakdown in children and adolescents: A cross-sectional analysis of two cohorts.

PubMed

Michels, Nathalie; Clarke, Gerard; Olavarria-Ramirez, Loreto; Gómez-Martínez, Sonia; Díaz, Ligia Esperanza; Marcos, Ascensión; Widhalm, Kurt; Carvalho, Livia A

2018-08-01

Tryptophan breakdown is an important mechanism in several diseases e.g. inflammation and stress-induced inflammation have been associated with the development of depression via enhanced tryptophan breakdown. Depression is a major public health problem which commonly starts during adolescence, thus identifying underlying mechanisms during early life is crucial in prevention. The aim of this work was to verify whether independent and interacting associations of psychosocial stress and inflammation on tryptophan breakdown already exist in children and adolescents as a vulnerable age group. Two cross-sectional population-based samples of children/adolescents (8-18 y) were available: 315 from the European HELENA study and 164 from the Belgian ChiBS study. In fasting serum samples, tryptophan, kynurenine, kynurenic acid, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (IFN)-ɣ, soluble vascular adhesion molecule 1 (sVCAM1) and soluble intercellular adhesion molecule 1 (sICAM1) were measured. Psychological stress was measured by stress reports (subjective) and cortisol (objective - awakening salivary cortisol or hair cortisol). Linear regressions with stress or inflammation as predictor were adjusted for age, sex, body mass index, puberty, socio-economic status and country. In both cohorts, inflammation as measured by higher levels of CRP, sVCAM1 and sICAM1 was associated with kynurenine/tryptophan ratio and thus enhanced tryptophan breakdown (beta: 0.145-0.429). Psychological stress was only associated with tryptophan breakdown in the presence of higher inflammatory levels (TNF-α in both populations). Inflammatory levels were replicable key in enhancing tryptophan breakdown along the kynurenine pathway, even at young age and in a non-clinical sample. The stress-inflammation interaction indicated that only the stress exposures inducing higher inflammatory levels (or in an already existing inflammatory status) were associated with more tryptophan breakdown. This data further contributes to our understanding of pathways to disease development, and may help identifying those more likely to develop stress or inflammation-related illnesses. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of tryptophan-rich breakfast and light exposure during the daytime on melatonin secretion at night.

PubMed

Fukushige, Haruna; Fukuda, Yumi; Tanaka, Mizuho; Inami, Kaoru; Wada, Kai; Tsumura, Yuki; Kondo, Masayuki; Harada, Tetsuo; Wakamura, Tomoko; Morita, Takeshi

2014-11-19

The purpose of the present study is to investigate effects of tryptophan intake and light exposure on melatonin secretion and sleep by modifying tryptophan ingestion at breakfast and light exposure during the daytime, and measuring sleep quality (by using actigraphy and the OSA sleep inventory) and melatonin secretion at night. Thirty three male University students (mean ± SD age: 22 ± 3.1 years) completed the experiments lasting 5 days and 4 nights. The subjects were randomly divided into four groups: Poor*Dim (n = 10), meaning a tryptophan-poor breakfast (55 mg/meal) in the morning and dim light environment (<50 lx) during the daytime; Rich*Dim (n = 7), tryptophan-rich breakfast (476 mg/meal) and dim light environment; Poor*Bright (n = 9), tryptophan-poor breakfast and bright light environment (>5,000 lx); and Rich*Bright (n = 7), tryptophan-rich breakfast and bright light. Saliva melatonin concentrations on the fourth day were significantly lower than on the first day in the Poor*Dim group, whereas they were higher on the fourth day in the Rich*Bright group. Creatinine-adjusted melatonin in urine showed the same direction as saliva melatonin concentrations. These results indicate that the combination of a tryptophan-rich breakfast and bright light exposure during the daytime could promote melatonin secretion at night; further, the observations that the Rich*Bright group had higher melatonin concentrations than the Rich*Dim group, despite no significant differences being observed between the Poor*Dim and Rich*Dim groups nor the Poor*Bright and Rich*Bright groups, suggest that bright light exposure in the daytime is an important contributor to raised melatonin levels in the evening. This study is the first to report the quantitative effects of changed tryptophan intake at breakfast combined with daytime light exposure on melatonin secretion and sleep quality. Evening saliva melatonin secretion changed significantly and indicated that a tryptophan-rich breakfast and bright light exposure during the daytime promoted melatonin secretion at this time.

Altered response to tryptophan supplementation after long-term abstention from MDMA (ecstasy) is highly correlated with human memory function.

PubMed

Curran, H Valerie; Verheyden, Suzanne L

2003-08-01

MDMA (ecstasy; +3,4-methylenedioxymethamphetamine) damages brain serotonin (5-HT) neurons and, in non-human primates, a loss of various 5-HT axonal markers persists for several years. This raises the question of whether long lasting effects occur in human beings that persist even after they have stopped using MDMA. We therefore assessed the effects of an indirect 5-HT manipulation on functions thought to be affected by MDMA use in people who had stopped using MDMA (ex-users) compared with continuing users and non-users. Ninety-six participants were recruited: 32 ex-users who had stopped using MDMA for >1 year (mean, 2.4 years); 32 current users and 32 polydrug controls who had never used MDMA but were matched with ex-users and controls on cannabis use and pre-morbid IQ. Participants were given an amino acid mixture that contained either no tryptophan (T-) or augmented tryptophan (T+) and assessed before and 5 h after the drink on measures of cognitive function and mood. T+ and T- produced plasma tryptophan augmentation and depletion, respectively, in all three groups. Ex-users' plasma tryptophan levels in response to T+ were significantly higher than other groups. Ex-users' performance on a delayed prose recall task improved after T+ and lessened after T-. Changes in ex-users' free plasma tryptophan levels correlated highly (r=-0.9) with their baseline performance on immediate and delayed prose recall; change in total plasma tryptophan correlated (r=-0.81) with delayed recall. Further, total baseline plasma tryptophan correlated with number of years they had used MDMA before quitting. Baseline differences between groups were found on learning, working memory, aggression and impulsivity. T- did not produce differential effects in the three groups. Our results suggest that prolonged abstinence from MDMA might be associated with altered tryptophan metabolism. Ex-users showing the poorest memory function at baseline were also those who metabolised least tryptophan. These findings may reflect pre-morbid differences in 5-HT function of those who stop using this drug or consequences of MDMA use that emerge after abstention. Aggression is also associated with MDMA use and subsequent abstinence.

Serum Analysis of Tryptophan Catabolism Pathway: Correlation with Crohn’s Disease Activity

PubMed Central

Gupta, Nitin K; Thaker, Ameet I; Kanuri, Navya; Riehl, Terrence E; Rowley, Christopher W; Stenson, William F; Ciorba, Matthew A

2011-01-01

BACKGROUND Indoleamine 2,3 dioxygenase 1 (IDO1) is a tryptophan catabolizing enzyme with immunotolerance promoting functions. We sought to determine if increased gut expression of IDO1 in Crohn’s disease (CD) would result in detectable changes in serum levels of tryptophan and the initial IDO1 pathway catabolite, kynurenine. METHODS Individuals were prospectively enrolled through the Washington University Digestive Diseases Research Center. Montreal classification was used for disease phenotyping. Disease severity was categorized by physician’s global assessment. Serum tryptophan and kynurenine were measured by high pressure liquid chromatography. IDO1 immunohistochemical staining was performed on formalin-fixed tissue blocks. RESULTS 25 CD patients and 11 controls were enrolled. 8 CD patients had serum collected at two different time points and levels of disease activity. Strong IDO1 expression exists in both the lamina propria and epithelium during active CD compared to controls. Suppressed serum tryptophan levels and an elevated kynurenine/tryptophan (K/T) ratio were found in individuals with active CD as compared to those in remission or the control population. K/T ratios correlated positively with disease activity as well as with C-reactive protein and erythrocyte sedimentation rate. In the subgroup of CD patients with two serum measurements, tryptophan levels elevated while kynurenine levels and the K/T ratio lowered as the disease activity lessened. CONCLUSIONS IDO1 expression in Crohn’s disease is associated with lower serum tryptophan and an elevated K/T ratio. These levels may serve a reasonable objective marker of gut mucosal immune activation and surrogate for Crohn’s Disease activity. PMID:21823214

Association of Tryptophan Metabolites with Incident Type 2 Diabetes in the PREDIMED Trial: A Case-Cohort Study.

PubMed

Yu, Edward; Papandreou, Christopher; Ruiz-Canela, Miguel; Guasch-Ferre, Marta; Clish, Clary B; Dennis, Courtney; Liang, Liming; Corella, Dolores; Fitó, Montserrat; Razquin, Cristina; Lapetra, José; Estruch, Ramón; Ros, Emilio; Cofán, Montserrat; Arós, Fernando; Toledo, Estefania; Serra-Majem, Lluis; Sorlí, José V; Hu, Frank B; Martinez-Gonzalez, Miguel A; Salas-Salvado, Jordi

2018-06-08

Metabolites of the tryptophan-kynurenine pathway (i.e., tryptophan, kynurenine, kynurenic acid, quinolinic acid, 3-hydroxyanthranilic) may be associated with diabetes development. Using a case-cohort design nested in the Prevención con Dieta Mediterránea (PREDIMED) study, we studied the associations of baseline and 1-year changes of these metabolites with incident type 2 diabetes (T2D). Plasma metabolite concentrations were quantified via LC-MS for n = 641 in a randomly selected subcohort and 251 incident cases diagnosed during 3.8 years of median follow-up. Weighted Cox models adjusted for age, sex, body mass index, and other T2D risk factors were used. Contrary to our hypothesis, baseline tryptophan was associated with higher risk of incident T2D (hazard ratio = 1.29; 95% CI, 1.04-1.61 per SD). Positive changes in quinolinic acid from baseline to 1 year were associated with a higher risk of T2D (hazard ratio = 1.39; 95% CI, 1.09-1.77 per SD). Baseline tryptophan and kynurenic acid were directly associated with changes in homeostatic model assessment for insulin resistance (HOMA-IR) from baseline to 1 year. Concurrent changes in kynurenine, quinolinic acid, 3-hydroxyanthranilic acid, and kynurenine/tryptophan ratio were associated with baseline-to-1-year changes in HOMA-IR. Baseline tryptophan and 1-year increases in quinolinic acid were positively associated with incident T2D. Baseline and 1-year changes in tryptophan metabolites predicted changes in HOMA-IR. © 2018 American Association for Clinical Chemistry.

Positions of Trp Codons in the Leader Peptide-Coding Region of the at Operon Influence Anti-Trap Synthesis and trp Operon Expression in Bacillus licheniformis▿

PubMed Central

Levitin, Anastasia; Yanofsky, Charles

2010-01-01

Tryptophan, phenylalanine, tyrosine, and several other metabolites are all synthesized from a common precursor, chorismic acid. Since tryptophan is a product of an energetically expensive biosynthetic pathway, bacteria have developed sensing mechanisms to downregulate synthesis of the enzymes of tryptophan formation when synthesis of the amino acid is not needed. In Bacillus subtilis and some other Gram-positive bacteria, trp operon expression is regulated by two proteins, TRAP (the tryptophan-activated RNA binding protein) and AT (the anti-TRAP protein). TRAP is activated by bound tryptophan, and AT synthesis is increased upon accumulation of uncharged tRNATrp. Tryptophan-activated TRAP binds to trp operon leader RNA, generating a terminator structure that promotes transcription termination. AT binds to tryptophan-activated TRAP, inhibiting its RNA binding ability. In B. subtilis, AT synthesis is upregulated both transcriptionally and translationally in response to the accumulation of uncharged tRNATrp. In this paper, we focus on explaining the differences in organization and regulatory functions of the at operon's leader peptide-coding region, rtpLP, of B. subtilis and Bacillus licheniformis. Our objective was to correlate the greater growth sensitivity of B. licheniformis to tryptophan starvation with the spacing of the three Trp codons in its at operon leader peptide-coding region. Our findings suggest that the Trp codon location in rtpLP of B. licheniformis is designed to allow a mild charged-tRNATrp deficiency to expose the Shine-Dalgarno sequence and start codon for the AT protein, leading to increased AT synthesis. PMID:20061467

[Metabolic disturbance of tryptophan-nicotinamide conversion pathway by putative endocrine disruptors, bisphenol A and styrene monomer].

PubMed

Fukuwatari, Tsutomu; Toriochi, Mai; Ohta, Mari; Sasaki, Ryuzo; Shibata, Katsumi

2004-02-01

Bisphenol A, a monomer of polycarbonate plastics, disturbed the conversion pathway of the amino acid tryptophan to the vitamin nicotinamide. The conversion ratio of tryptophan to nicotinamide was reduced to 1/15 by feeding a diet containing 1% bisphenol A. A putative disturbing reaction is kynurenine-->3-hydroxykynurenine, which is catalyzed by kynurenine monohydroxylase. This is an FAD-enzyme and requires NADPH as a coenzyme. Styrene monomer (1% addition to a normal diet) did not affect the food intake or the body weight, but slightly reduced the conversion ratio of tryptophan-nicotinamide.

[Changes in the tryptophan content during the technological manufacturing processes of several wheat flour products].

PubMed

Horvatić, M; Grüner, M

1989-12-01

The change of tryptophan contents in proteins of bread and cookies under technological processing conditions were investigated. Tryptophan contents in all cookie samples were noted to be significantly (p = 0.05) reduced in relation to corresponding dough. The relative decreases are significantly correlated with fat content and the degree of unsaturation of fats in the dough of cookies (r = 0.802 and r = 0.777, p = 0.01), independently of various physical parameters during different cookie samples' processing. Tryptophan decrease in proteins of bread during baking was not significant.

Delaying aging and the aging-associated decline in protein homeostasis by inhibition of tryptophan degradation

PubMed Central

van der Goot, Annemieke T.; Zhu, Wentao; Vázquez-Manrique, Rafael P.; Seinstra, Renée I.; Dettmer, Katja; Michels, Helen; Farina, Francesca; Krijnen, Jasper; Melki, Ronald; Buijsman, Rogier C.; Ruiz Silva, Mariana; Thijssen, Karen L.; Kema, Ido P.; Neri, Christian; Oefner, Peter J.; Nollen, Ellen A. A.

2012-01-01

Toxicity of aggregation-prone proteins is thought to play an important role in aging and age-related neurological diseases like Parkinson and Alzheimer’s diseases. Here, we identify tryptophan 2,3-dioxygenase (tdo-2), the first enzyme in the kynurenine pathway of tryptophan degradation, as a metabolic regulator of age-related α-synuclein toxicity in a Caenorhabditis elegans model. Depletion of tdo-2 also suppresses toxicity of other heterologous aggregation-prone proteins, including amyloid-β and polyglutamine proteins, and endogenous metastable proteins that are sensors of normal protein homeostasis. This finding suggests that tdo-2 functions as a general regulator of protein homeostasis. Analysis of metabolite levels in C. elegans strains with mutations in enzymes that act downstream of tdo-2 indicates that this suppression of toxicity is independent of downstream metabolites in the kynurenine pathway. Depletion of tdo-2 increases tryptophan levels, and feeding worms with extra l-tryptophan also suppresses toxicity, suggesting that tdo-2 regulates proteotoxicity through tryptophan. Depletion of tdo-2 extends lifespan in these worms. Together, these results implicate tdo-2 as a metabolic switch of age-related protein homeostasis and lifespan. With TDO and Indoleamine 2,3-dioxygenase as evolutionarily conserved human orthologs of TDO-2, intervening with tryptophan metabolism may offer avenues to reducing proteotoxicity in aging and age-related diseases. PMID:22927396

The association between the hypothalamic pituitary adrenal axis and tryptophan metabolism in persons with recurrent major depressive disorder and healthy controls.

PubMed

Sorgdrager, F J H; Doornbos, B; Penninx, B W J H; de Jonge, P; Kema, I P

2017-11-01

Persistent changes in serotonergic and hypothalamic pituitary adrenal (HPA) axis functioning are implicated in recurrent types of major depressive disorder (MDD). Systemic tryptophan levels, which influence the rate of serotonin synthesis, are regulated by glucocorticoids produced along the HPA axis. We investigated tryptophan metabolism and its association with HPA axis functioning in single episode MDD, recurrent MDD and non-depressed individuals. We included depressed individuals (n = 1320) and controls (n = 406) from the Netherlands Study of Depression and Anxiety (NESDA). The kynurenine to tryptophan ratio (kyn/trp ratio) was established using serum kynurenine and tryptophan levels. Several HPA axis parameters were calculated using salivary cortisol samples. We adjusted the regression analyses for a wide range of potential confounders and differentiated between single episode MDD, recurrent MDD and control. Tryptophan, kynurenine and the kyn/trp ratio did not differ between controls and depressed individuals. Increased evening cortisol levels were associated with a decreased kyn/trp ratio in the total sample (Crude: β = -.102, p < .001; Adjusted: β = -.083, p < .001). This association was found to be restricted to recurrently depressed individuals (Crude: β = -.196, p < .001; Adjusted: β = -.145, p = .001). Antidepressant treatment did not affect this association. Our results suggest that an imbalance between HPA axis function and tryptophan metabolism could be involved in recurrent depression. Copyright © 2017 Elsevier B.V. All rights reserved.

Plant-Microbe Communication Enhances Auxin Biosynthesis by a Root-Associated Bacterium, Bacillus amyloliquefaciens SQR9.

PubMed

Liu, Yunpeng; Chen, Lin; Zhang, Nan; Li, Zunfeng; Zhang, Guishan; Xu, Yu; Shen, Qirong; Zhang, Ruifu

2016-04-01

Mechanisms by which beneficial rhizobacteria promote plant growth include tryptophan-dependent indole-3-acetic acid (IAA) synthesis. The abundance of tryptophan in the rhizosphere, however, may influence the level of benefit provided by IAA-producing rhizobacteria. This study examined the cucumber-Bacillus amyloliquefaciens SQR9 system and found that SQR9, a bacterium previously shown to enhance the growth of cucumber, increased root secretion of tryptophan by three- to fourfold. Using a split-root system, SQR9 colonization of roots in one chamber not only increased tryptophan secretion from the noninoculated roots but also increased the expression of the cucumber tryptophan transport gene but not the anthranilate synthesis gene in those roots. The increased tryptophan in isolated rhizosphere exudates was sufficient to support increased IAA production by SQR9. Moreover, SQR9 colonization of roots in one chamber in the split-root system resulted in sufficient tryptophan production by the other roots to upregulate SQR9 IAA biosynthesis genes, including a 27-fold increase in the indole-3-acetonitrilase gene yhcX during subsequent colonization of those roots. Deletion of yhcX eliminated SQR9-mediated increases in root surface area, likely by reducing IAA-stimulated lateral root growth. This study demonstrates a chemical dialogue between B. amyloliquefaciens and cucumber in which this communication contributes to bacteria-mediated plant-growth enhancement.

Towards an Integrative Understanding of tRNA Aminoacylation–Diet–Host–Gut Microbiome Interactions in Neurodegeneration

PubMed Central

Paley, Elena L.

2018-01-01

Transgenic mice used for Alzheimer’s disease (AD) preclinical experiments do not recapitulate the human disease. In our models, the dietary tryptophan metabolite tryptamine produced by human gut microbiome induces tryptophanyl-tRNA synthetase (TrpRS) deficiency with consequent neurodegeneration in cells and mice. Dietary supplements, antibiotics and certain drugs increase tryptamine content in vivo. TrpRS catalyzes tryptophan attachment to tRNAtrp at initial step of protein biosynthesis. Tryptamine that easily crosses the blood–brain barrier induces vasculopathies, neurodegeneration and cell death via TrpRS competitive inhibition. TrpRS inhibitor tryptophanol produced by gut microbiome also induces neurodegeneration. TrpRS inhibition by tryptamine and its metabolites preventing tryptophan incorporation into proteins lead to protein biosynthesis impairment. Tryptophan, a least amino acid in food and proteins that cannot be synthesized by humans competes with frequent amino acids for the transport from blood to brain. Tryptophan is a vulnerable amino acid, which can be easily lost to protein biosynthesis. Some proteins marking neurodegenerative pathology, such as tau lack tryptophan. TrpRS exists in cytoplasmic (WARS) and mitochondrial (WARS2) forms. Pathogenic gene variants of both forms cause TrpRS deficiency with consequent intellectual and motor disabilities in humans. The diminished tryptophan-dependent protein biosynthesis in AD patients is a proof of our model-based disease concept. PMID:29587458

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, F.D.; Smith, T.K.; Bayley, H.S.

Experiments were conducted to determine the effect of varying concentrations of dietary tryptophan on growth rate and protein synthesis in edible muscle tissues of growing swine. A total of 45 immature swine (initial weight approximately 24 kg) were fed corn-gelatin diets containing 0.5 (n = 8), 0.8 (n = 10), 1.3 (n = 10), 1.5 (n = 7) or 2.0 (n = 10) g tryptophan/kg diet for 35 d. Animals fed 0.5 and 0.8 g tryptophan/kg grew more slowly, consumed less feed and had a lower efficiency of feed utilization than animals fed higher concentrations of tryptophan. Thirty similar animalsmore » were used in a second experiment. Diets containing 0.5, 0.8, 1.0, 1.5 or 2.0 g tryptophan/kg diet (n = 6) were fed for 14 d, after which all animals were killed and samples were taken of longissimus dorsi, triceps brachii and biceps femoris. Protein synthetic activity was determined by monitoring the incorporation of (/sup 14/C)phenylalanine into protein in vitro. There was no significant difference in synthetic activity between different muscle types. There was no effect of diet on the activity of the muscle soluble protein fraction. The activity of the muscle ribosomal fraction, however, was positively correlated with increasing concentrations of dietary tryptophan. It was concluded that tryptophan has the potential to regulate muscle protein synthesis in a manner beyond serving simply as a component of protein.« less

Single Turnover Kinetics of Tryptophan Hydroxylase: Evidence for a New Intermediate in the Reaction of the Aromatic Amino Acid Hydroxylases

PubMed Central

Pavon, Jorge Alex; Eser, Bekir; Huynh, Michaela T.; Fitzpatrick, Paul F.

2010-01-01

Tryptophan hydroxylase (TrpH) uses a non-heme mononuclear iron center to catalyze the tetrahydropterin-dependent hydroxylation of tryptophan to 5-hydroxytryptophan. The reactions of the TrpH·Fe(II), TrpH·Fe(II)·tryptophan, TrpH·Fe(II)·6MePH4·tryptophan, and TrpH·Fe(II)·6MePH4·phenylalanine complexes with O2 were monitored by stopped-flow absorbance spectroscopy and rapid quench methods. The second-order rate constant for the oxidation of TrpH·Fe(II) has a value of 104 M−1s−1 irrespective of the presence of tryptophan. Stopped-flow absorbance analyses of the reaction of the TrpH·Fe(II)·6MePH4·tryptophan complex with oxygen are consistent with the initial step being reversible binding of oxygen, followed by the formation with a rate constant of 65 s−1 of an intermediate I that has maximal absorbance at 420 nm. The rate constant for decay of I, 4.4 s−1, matches that for formation of the 4a-hydroxypterin product monitored at 248 nm. Chemical-quench analyses show that 5-hydroxytryptophan forms with a rate constant of 1.3 s−1, and that overall turnover is limited by a subsequent slow step, presumably product release, with a rate constant of 0.2 s−1. All of the data with tryptophan as substrate can be described by a five-step mechanism. In contrast, with phenylalanine as substrate, the reaction can be described by three steps: a second-order reaction with oxygen to form I, decay of I as tyrosine forms, and slow product release. PMID:20687613

Aniline Is an Inducer, and Not a Precursor, for Indole Derivatives in Rubrivivax benzoatilyticus JA2

PubMed Central

Mohammed, Mujahid; Ch, Sasikala; Ch, Ramana V.

2014-01-01

Rubrivivax benzoatilyticus JA2 and other anoxygenic photosynthetic bacteria produce indole derivatives when exposed to aniline, a xenobiotic compound. Though this phenomenon has been reported previously, the role of aniline in the production of indoles is still a biochemical riddle. The present study aims at understanding the specific role of aniline (as precursor or stimulator) in the production of indoles and elucidating the biochemical pathway of indoles in aniline-exposed cells by using stable isotope approaches. Metabolic profiling revealed tryptophan accumulation only in aniline exposed cells along with indole 3-acetic acid (IAA) and indole 3-aldehyde (IAld), the two major catabolites of tryptophan. Deuterium labelled aniline feeding studies revealed that aniline is not a precursor of indoles in strain JA2. Further, production of indoles only in aniline-exposed cells suggests that aniline is an indoles stimulator. In addition, production of indoles depended on the presence of a carbon source, and production enhanced when carbon sources were added to the culture. Isotope labelled fumarate feeding identified, fumarate as the precursor of indole, indicating de novo synthesis of indoles. Glyphosate (shikimate pathway inhibitor) inhibited the indoles production, accumulation of tryptophan, IAA and IAld indicating that indoles synthesis in strain JA2 occurs via the de novo shikimate pathway. The up-regulation of anthranilate synthase gene and induction of anthranilate synthase activity correlated well with tryptophan production in strain JA2. Induction of tryptophan aminotransferase and tryptophan 2-monooxygenase activities corroborated well with IAA levels, suggesting that tryptophan catabolism occurs simultaneously in aniline exposed cells. Our study demonstrates that aniline (stress) stimulates tryptophan/indoles synthesis via the shikimate pathway by possibly modulating the metabolic pathway. PMID:24533057

Aniline is an inducer, and not a precursor, for indole derivatives in Rubrivivax benzoatilyticus JA2.

PubMed

Mujahid, Mohammed; Sasikala, Ch; Ramana, Ch V

2014-01-01

Rubrivivax benzoatilyticus JA2 and other anoxygenic photosynthetic bacteria produce indole derivatives when exposed to aniline, a xenobiotic compound. Though this phenomenon has been reported previously, the role of aniline in the production of indoles is still a biochemical riddle. The present study aims at understanding the specific role of aniline (as precursor or stimulator) in the production of indoles and elucidating the biochemical pathway of indoles in aniline-exposed cells by using stable isotope approaches. Metabolic profiling revealed tryptophan accumulation only in aniline exposed cells along with indole 3-acetic acid (IAA) and indole 3-aldehyde (IAld), the two major catabolites of tryptophan. Deuterium labelled aniline feeding studies revealed that aniline is not a precursor of indoles in strain JA2. Further, production of indoles only in aniline-exposed cells suggests that aniline is an indoles stimulator. In addition, production of indoles depended on the presence of a carbon source, and production enhanced when carbon sources were added to the culture. Isotope labelled fumarate feeding identified, fumarate as the precursor of indole, indicating de novo synthesis of indoles. Glyphosate (shikimate pathway inhibitor) inhibited the indoles production, accumulation of tryptophan, IAA and IAld indicating that indoles synthesis in strain JA2 occurs via the de novo shikimate pathway. The up-regulation of anthranilate synthase gene and induction of anthranilate synthase activity correlated well with tryptophan production in strain JA2. Induction of tryptophan aminotransferase and tryptophan 2-monooxygenase activities corroborated well with IAA levels, suggesting that tryptophan catabolism occurs simultaneously in aniline exposed cells. Our study demonstrates that aniline (stress) stimulates tryptophan/indoles synthesis via the shikimate pathway by possibly modulating the metabolic pathway.

Functional analysis of human aromatic amino acid transporter MCT10/TAT1 using the yeast Saccharomyces cerevisiae.

PubMed

Uemura, Satoshi; Mochizuki, Takahiro; Kurosaka, Goyu; Hashimoto, Takanori; Masukawa, Yuki; Abe, Fumiyoshi

2017-10-01

Tryptophan is an essential amino acid in humans and an important serotonin and melatonin precursor. Monocarboxylate transporter MCT10 is a member of the SLC16A family proteins that mediates low-affinity tryptophan transport across basolateral membranes of kidney, small intestine, and liver epithelial cells, although the precise transport mechanism remains unclear. Here we developed a simple functional assay to analyze tryptophan transport by human MCT10 using a deletion mutant for the high-affinity tryptophan permease Tat2 in Saccharomyces cerevisiae. tat2Δtrp1 cells are defective in growth in YPD medium because tyrosine present in the medium competes for the low-affinity tryptophan permease Tat1 with tryptophan. MCT10 appeared to allow growth of tat2Δtrp1 cells in YPD medium, and accumulate in cells deficient for Rsp5 ubiquitin ligase. These results suggest that MCT10 is functional in yeast, and is subject to ubiquitin-dependent quality control. Whereas growth of Tat2-expressing cells was significantly impaired by neutral pH, that of MCT10-expressing cells was nearly unaffected. This property is consistent with the transport mechanism of MCT10 via facilitated diffusion without a need for pH gradient across the plasma membrane. Single-nucleotide polymorphisms (SNPs) are known to occur in the human MCT10 coding region. Among eight SNP amino acid changes in MCT10, the N81K mutation completely abrogated tryptophan import without any abnormalities in the expression or localization. In the MCT10 modeled structure, N81 appeared to protrude into the putative trajectory of tryptophan. Plasma membrane localization of MCT10 and the variant proteins was also verified in human embryonic kidney 293T cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Tryptophan pathway alterations in the postpartum period and in acute postpartum psychosis and depression.

PubMed

Veen, Cato; Myint, Aye Mu; Burgerhout, Karin M; Schwarz, Markus J; Schütze, Gregor; Kushner, Steven A; Hoogendijk, Witte J; Drexhage, Hemmo A; Bergink, Veerle

2016-01-01

Women are at very high risk for the first onset of acute and severe mood disorders the first weeks after delivery. Tryptophan breakdown is increased as a physiological phenomenon of the postpartum period and might lead to vulnerability for affective psychosis (PP) and severe depression (PD). The aim of the current study was to investigate alterations in tryptophan breakdown in the physiological postpartum period compared to patients with severe postpartum mood disorders. We included 52 patients (29 with PP, 23 with PD), 52 matched healthy postpartum women and 29 healthy non-postpartum women. Analyzes of serum tryptophan metabolites were performed using LC-MS/MS system for tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid and 5-hydroxyindoleacetic acid. The first two months of the physiological postpartum period were characterized by low tryptophan levels, increased breakdown towards kynurenine and a downstream shift toward the 3-OH-kynurenine arm, away from the kynurenic acid arm. Kynurenine was significantly lower in patients with PP and PD as compared to healthy postpartum women (p=0.011 and p=0.001); the remaining tryptophan metabolites demonstrated few differences between patients and healthy postpartum women. Low prevalence of the investigated disorders and strict exclusion criteria to obtain homogenous groups, resulted in relatively small sample sizes. The high kynurenine levels and increased tryptophan breakdown as a phenomenon of the physiological postpartum period was not present in patients with severe postpartum mood disorders. No differences were observed in the levels of the 'neurotoxic' 3-OH-kynurenine and the 'neuroprotective' kynurenic acid arms between patients and healthy postpartum women. Copyright © 2015 Elsevier B.V. All rights reserved.

Tryptophan and ATTO 590: mutual fluorescence quenching and exciplex formation.

PubMed

Bhattacharjee, Ujjal; Beck, Christie; Winter, Arthur; Wells, Carson; Petrich, Jacob W

2014-07-24

Investigation of fluorescence quenching of probes, such as ATTO dyes, is becoming an increasingly important topic owing to the use of these dyes in super-resolution microscopies and in single-molecule studies. Photoinduced electron transfer is their most important nonradiative pathway. Because of the increasing frequency of the use of ATTO and related dyes to investigate biological systems, studies are presented for inter- and intramolecular quenching of ATTO 590 with tryptophan. In order to examine intramolecular quenching, an ATTO 590-tryptophan conjugate was synthesized. It was determined that tryptophan is efficiently quenching ATTO 590 fluorescence by excited-state charge transfer and two charge transfer complexes are forming. In addition, it was discovered that an exciplex (whose lifetime is 5.6 ns) can be formed between tryptophan and ATTO 590, and it is suggested that the possibility of such exciplex formation should be taken into account when protein fluorescence is monitored in a system tagged with ATTO dyes.

Modulation of IAA production in cyanobacteria by tryptophan and light.

PubMed

Prasanna, Radha; Joshi, Monica; Rana, Anuj; Nain, Lata

2010-01-01

Cyanobacteria represent less a investigated group of prokaryote, in terms of their plant growth promoting potential, especially in relation to the production of phytohormones. The present investigation was aimed towards analyzing growth kinetics, indole acetic acid (IAA) production and acetylene reduction activity (ARA) as an index of nitrogen fixation in two selected cyanobacterial strains belonging to the genus Anabaena, as influenced by tryptophan supplementation and light:dark conditions. Interesting observations were recorded in terms of enhancement of IAA production accompanied by protein and chlorophyll accumulation in the two cyanobacterial strains grown in media without tryptophan and incubated under light:dark or continuous light conditions. Colorimetric and chromatographic analyses supported the observations that tryptophan is not essential as a precursor for IAA biosynthesis in these cyanobacteria. Further study is in progress to identify genes involved in the tryptophan independent pathway for IAA biosynthesis.

Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects

PubMed Central

Young, Simon N.

2013-01-01

The acute tryptophan depletion (ATD) technique has been used extensively to study the effect of low serotonin in the human brain. This review assesses the validity of a number of published criticisms of the technique and a number of previously unpublished potential criticisms. The conclusion is that ATD can provide useful information when results are assessed in conjunction with results obtained using other techniques. The best-established conclusion is that low serotonin function after tryptophan depletion lowers mood in some people. However, this does not mean that other variables, altered after tryptophan depletion, are necessarily related to low serotonin. Each aspect of brain function has to be assessed separately. Furthermore, a negative tryptophan depletion study does not mean that low serotonin cannot influence the variable studied. This review suggests gaps in knowledge that need to be filled and guidelines for carrying out ATD studies. PMID:23428157

Tryptophan-to-Tryptophan Energy Transfer in UV-B photoreceptor UVR8

NASA Astrophysics Data System (ADS)

Li, Xiankun; Zhong, Dongping

UVR8 (UV RESISTANCE LOCUS 8) protein is a UV-B photoreceptor in high plants. UVR8 is a homodimer that dissociates into monomers upon UV-B irradiation (280 nm to 315 nm), which triggers various protective mechanisms against UV damages. Uniquely, UVR8 does not contain any external chromophores and utilizes the UV-absorbing natural amino acid tryptophan (Trp) to perceive UV-B. Each UVR8 monomer has 14 tryptophan residues. However, only 2 epicenter Trp (W285 W233) are critical to the light induced dimer-to-monomer transformation. Here, we revealed, using site-directed mutagenesis and spectroscopy, a striking energy flow network, in which other tryptophan chromophores serve as antenna to transfer excitation energy to epicenter Trp, greatly enhancing UVR8 light-harvesting efficiency. Furthermore, Trp-to-Trp energy transfer rates were measured and agree well with theoretical values.

Low-molecular-weight compounds with anticoagulant activity from the scorpion Heterometrus laoticus venom.

PubMed

Thien, Tran Vu; Anh, Hoang Ngoc; Trang, Nguyen Thi Thuy; Trung, Phung Van; Khoa, Nguyen Cuu; Osipov, A V; Dubovskii, P V; Ivanov, I A; Arseniev, A S; Tsetlin, V I; Utkin, Yu N

2017-09-01

Low-molecular-weight compounds with anticoagulant activity were isolated from the scorpion Heterometrus laoticus venom. The determination of the structure of the isolated compounds by nuclear magnetic resonance and mass spectrometry showed that one of the isolated compounds is adenosine, and the other two are dipeptides leucyl-tryptophan and isoleucyl-tryptophan. The anticoagulant properties of adenosine, which is an inhibitor of platelet aggregation, is well known, but its presence in scorpion venom is shown for the first time. The ability of leucyl-tryptophan and isoleucyl-tryptophan to slow down blood clotting and their presence in scorpion venom are also established for the first time.

Reinvestigation of L-tryptophan picrate: Establishment of the existence of the L-tryptophan L-tryptophanium dimeric cation

NASA Astrophysics Data System (ADS)

Petrosyan, A. M.; Fleck, M.; Ghazaryan, V. V.

2013-03-01

A crystal structure redetermination of the L-tryptophan picrate crystal previously studied by Ishida et al. (Chem. Pharm. Bull. 41 (1993) 433-438) showed that it comprises L-tryptophan L-tryptophanium dimeric cation, one picrate anion and picric acid. The O⋯O distance of the O-H⋯O hydrogen bond in the dimeric cation is equal to 2.470(6) Å. The infrared spectrum of the crystal was registered and analyzed. The infrared spectrum of the crystals contains a broad absorption band centered at ca. 1170 cm-1, which is assigned to the stretching vibration of the O-H bond.

Tryptophan–Kynurenine Metabolism as a Common Mediator of Genetic and Environmental Impacts in Major Depressive Disorder: The Serotonin Hypothesis Revisited 40 Years Later

PubMed Central

Oxenkrug, Gregory F.

2011-01-01

The original 1969 Lancet paper proposed, “in depression the activity of liver tryptophan-pyrrolase is stimulated by raised blood corticosteroids levels, and metabolism of tryptophan is shunted away from serotonin production, and towards kynurenine production.” Discovery of neurotropic activity of kynurenines suggested that up-regulation of the tryptophan-kynurenine pathway not only augmented serotonin deficiency but also underlined depression-associated anxiety, psychosis and cognitive decline. The present review of genetic and hormonal factors regulating kynurenine pathway of tryptophan metabolism suggests that this pathway mediates both genetic and environmental mechanisms of depression. Rate-limiting enzymes of kynurenine formation, tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) are activated by stress hormones (TDO) and/or by pro-inflammatory cytokines (IDO). Simultaneous presence of high producers alleles of proinflammatory cytokines genes (e.g., interferon-gamma and tumor necrosis factor-alpha) determines the genetic predisposition to depression via up-regulation of IDO while impact of environmental stresses is mediated via hormonal activation of TDO. Tryptophan-kynurenine pathway represents a major meeting point of gene-environment interaction in depression and a new target for pharmacological intervention. PMID:20686200

Identification and expression analysis of the genes involved in serotonin biosynthesis and transduction in the field cricket Gryllus bimaculatus.

PubMed

Watanabe, T; Sadamoto, Hitoshi; Aonuma, H

2011-10-01

Serotonin (5-HT) modulates various aspects of behaviours such as aggressive behaviour and circadian behaviour in the cricket. To elucidate the molecular basis of the cricket 5-HT system, we identified 5-HT-related genes in the field cricket Gryllus bimaculatus DeGeer. Complementary DNA of tryptophan hydroxylase and phenylalanine-tryptophan hydroxylase, which convert tryptophan into 5-hydroxy-L-tryptophan (5-HTP), and that of aromatic L-amino acid decarboxylase, which converts 5-HTP into 5-HT, were isolated from a cricket brain cDNA library. In addition, four 5-HT receptor genes (5-HT(1A) , 5-HT(1B) , 5-HT(2α) , and 5-HT(7) ) were identified. Expression analysis of the tryptophan hydroxylase gene TRH and phenylalanine-tryptophan hydroxylase gene TPH, which are selectively involved in neuronal and peripheral 5-HT synthesis in Drosophila, suggested that two 5-HT synthesis pathways co-exist in the cricket neuronal tissues. The four 5-HT receptor genes were expressed in various tissues at differential expression levels, suggesting that the 5-HT system is widely distributed in the cricket. © 2011 The Authors. Insect Molecular Biology © 2011 The Royal Entomological Society.

Food can lift mood by affecting mood-regulating neurocircuits via a serotonergic mechanism.

PubMed

Kroes, Marijn C W; van Wingen, Guido A; Wittwer, Jonas; Mohajeri, M Hasan; Kloek, Joris; Fernández, Guillén

2014-01-01

It is commonly assumed that food can affect mood. One prevalent notion is that food containing tryptophan increases serotonin levels in the brain and alters neural processing in mood-regulating neurocircuits. However, tryptophan competes with other long-neutral-amino-acids (LNAA) for transport across the blood-brain-barrier, a limitation that can be mitigated by increasing the tryptophan/LNAA ratio. We therefore tested in a double-blind, placebo-controlled crossover study (N=32) whether a drink with a favourable tryptophan/LNAA ratio improves mood and modulates specific brain processes as assessed by functional magnetic resonance imaging (fMRI). We show that one serving of this drink increases the tryptophan/LNAA ratio in blood plasma, lifts mood in healthy young women and alters task-specific and resting-state processing in brain regions implicated in mood regulation. Specifically, Test-drink consumption reduced neural responses of the dorsal caudate nucleus during reward anticipation, increased neural responses in the dorsal cingulate cortex during fear processing, and increased ventromedial prefrontal-lateral prefrontal connectivity under resting-state conditions. Our results suggest that increasing tryptophan/LNAA ratios can lift mood by affecting mood-regulating neurocircuits. © 2013 Elsevier Inc. All rights reserved.

Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping.

PubMed

Guo, Cunlan; Yu, Xi; Refaely-Abramson, Sivan; Sepunaru, Lior; Bendikov, Tatyana; Pecht, Israel; Kronik, Leeor; Vilan, Ayelet; Sheves, Mordechai; Cahen, David

2016-09-27

Charge migration for electron transfer via the polypeptide matrix of proteins is a key process in biological energy conversion and signaling systems. It is sensitive to the sequence of amino acids composing the protein and, therefore, offers a tool for chemical control of charge transport across biomaterial-based devices. We designed a series of linear oligoalanine peptides with a single tryptophan substitution that acts as a "dopant," introducing an energy level closer to the electrodes' Fermi level than that of the alanine homopeptide. We investigated the solid-state electron transport (ETp) across a self-assembled monolayer of these peptides between gold contacts. The single tryptophan "doping" markedly increased the conductance of the peptide chain, especially when its location in the sequence is close to the electrodes. Combining inelastic tunneling spectroscopy, UV photoelectron spectroscopy, electronic structure calculations by advanced density-functional theory, and dc current-voltage analysis, the role of tryptophan in ETp is rationalized by charge tunneling across a heterogeneous energy barrier, via electronic states of alanine and tryptophan, and by relatively efficient direct coupling of tryptophan to a Au electrode. These results reveal a controlled way of modulating the electrical properties of molecular junctions by tailor-made "building block" peptides.

13C-tryptophan breath test detects increased catabolic turnover of tryptophan along the kynurenine pathway in patients with major depressive disorder

PubMed Central

Teraishi, Toshiya; Hori, Hiroaki; Sasayama, Daimei; Matsuo, Junko; Ogawa, Shintaro; Ota, Miho; Hattori, Kotaro; Kajiwara, Masahiro; Higuchi, Teruhiko; Kunugi, Hiroshi

2015-01-01

Altered tryptophan–kynurenine (KYN) metabolism has been implicated in major depressive disorder (MDD). The l-[1-13C]tryptophan breath test (13C-TBT) is a noninvasive, stable-isotope tracer method in which exhaled 13CO2 is attributable to tryptophan catabolism via the KYN pathway. We included 18 patients with MDD (DSM-IV) and 24 age- and sex-matched controls. 13C-tryptophan (150 mg) was orally administered and the 13CO2/12CO2 ratio in the breath was monitored for 180 min. The cumulative recovery rate during the 180-min test (CRR0–180; %), area under the Δ13CO2-time curve (AUC; %*min), and the maximal Δ13CO2 (Cmax; %) were significantly higher in patients with MDD than in the controls (p = 0.004, p = 0.008, and p = 0.002, respectively). Plasma tryptophan concentrations correlated negatively with Cmax in both the patients and controls (p = 0.020 and p = 0.034, respectively). Our results suggest that the 13C-TBT could be a novel biomarker for detecting a subgroup of MDD with increased tryptophan–KYN metabolism. PMID:26524975

Tryptophan circuit in fatigue: From blood to brain and cognition.

PubMed

Yamashita, Masatoshi; Yamamoto, Takanobu

2017-11-15

Brain tryptophan and its neuroactive metabolites play key roles in central fatigue. However, previous brain function analysis targets may have included both glia and neurons together. Here, we clarified the fatigue-cognitive circuit of the central-peripheral linkage, including the role of glial-neuronal interaction in cognition. Using a rat model of central fatigue induced by chronic sleep disorder (CFSD), we isolated presynaptic terminals and oligodendrocytes. Results showed that compared to control group, presynaptic levels of tryptophan, kynurenine, and kynurenic acid, but not serotonin, in the CFSD group were higher in the hypothalamus and hippocampus. Moreover, CFSD group had higher oligodendrocytic levels of tryptophan, and impaired spatial cognitive memory accuracy and increased hyperactivity and impulsivity. These findings suggest that dynamic change in glial-neuronal interactions within the hypothalamus-hippocampal circuit causes central fatigue, and increased tryptophan-kynurenic acid pathway activity in this circuit causes reduced cognitive function. Additionally, CFSD group had 1.5 times higher plasma levels of tryptophan and kynurenine. Furthermore, in rats undergoing intraperitoneal administration of kynurenine (100mg/kg) versus vehicle, kynurenine-treated rats showed enhanced production of kynurenic acid in the hippocampus, with suppressed recall of retained spatial cognitive memory. The study revealed that uptake of periphery-derived kynurenine and tryptophan into the brain enhances kynurenic acid production in the brain, and the three factors produce amplification effect involved in the role of central-peripheral linkage in central fatigue, triggering cognitive dysfunction. Copyright © 2017 Elsevier B.V. All rights reserved.

L-Tryptophan Production in Escherichia coli Improved by Weakening the Pta-AckA Pathway

PubMed Central

Liu, Lina; Duan, Xuguo; Wu, Jing

2016-01-01

Acetate accumulation during the fermentation process of Escherichia coli FB-04, an L-tryptophan production strain, is detrimental to L-tryptophan production. In an initial attempt to reduce acetate formation, the phosphate acetyltransferase gene (pta) from E. coli FB-04 was deleted, forming strain FB-04(Δpta). Unfortunately, FB-04(Δpta) exhibited a growth defect. Therefore, pta was replaced with a pta variant (pta1) from E. coli CCTCC M 2016009, forming strain FB-04(pta1). Pta1 exhibits lower catalytic capacity and substrate affinity than Pta because of a single amino acid substitution (Pro69Leu). FB-04(pta1) lacked the growth defect of FB-04(Δpta) and showed improved fermentation performance. Strain FB-04(pta1) showed a 91% increase in L-tryptophan yield in flask fermentation experiments, while acetate production decreased by 35%, compared with its parent FB-04. Throughout the fed-batch fermentation process, acetate accumulation by FB-04(pta1) was slower than that by FB-04. The final L-tryptophan titer of FB-04(pta1) reached 44.0 g/L, representing a 15% increase over that of FB-04. Metabolomics analysis showed that the pta1 genomic substitution slightly decreased carbon flux through glycolysis and significantly increased carbon fluxes through the pentose phosphate and common aromatic pathways. These results indicate that this strategy enhances L-tryptophan production and decreases acetate accumulation during the L-tryptophan fermentation process. PMID:27348810

Tripping Up Trp: Modification of Protein Tryptophan Residues by Reactive Oxygen Species, Modes of Detection, and Biological Consequences

PubMed Central

Ehrenshaft, Marilyn; Deterding, Leesa J.; Mason, Ronald P.

2015-01-01

Proteins comprise a majority of the dry weight of a cell, rendering them a major target for oxidative modification. Oxidation of proteins can result in significant alterations in protein molecular mass such as breakage of the polypeptide backbone, and/or polymerization of monomers into dimers, multimers and sometimes into insoluble aggregates. Protein oxidation can also result in structural changes to amino acid residue side chains, conversions which have only a modest effect on protein size but can have widespread consequences for protein function. There are a wide range of rate constants for amino acid reactivity, with cysteine, methionine, tyrosine, phenylalanine and tryptophan having the highest rate constants with commonly encountered biological oxidants. Free tryptophan and tryptophan protein residues react at a diffusion limited rate with hydroxyl radical, and also have high rate constants for reactions with singlet oxygen and ozone. Although oxidation of proteins in general and tryptophan residues specifically can have effects detrimental to the health of cells and organisms, some modifications are neutral while others contribute to the function of the protein in question or may act as a signal that damaged proteins need to be replaced. This review provides a brief overview of the chemical mechanisms by which tryptophan residues become oxidized, presents both the strengths and weaknesses of some of the techniques used to detect these oxidative interactions and discusses selected examples of the biological consequences of tryptophan oxidation in proteins from animals, plants and microbes. PMID:26393422

Serotonergic contribution to boys' behavioral regulation.

PubMed

Nantel-Vivier, Amélie; Pihl, Robert O; Young, Simon N; Parent, Sophie; Bélanger, Stacey Ageranioti; Sutton, Rachel; Dubois, Marie-Eve; Tremblay, Richard E; Séguin, Jean R

2011-01-01

Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure. Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500 mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered. Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter. The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors.

Beyond Tryptophan Synthase: Identification of Genes That Contribute to Chlamydia trachomatis Survival during Gamma Interferon-Induced Persistence and Reactivation

PubMed Central

Muramatsu, Matthew K.; Brothwell, Julie A.; Stein, Barry D.; Putman, Timothy E.; Rockey, Daniel D.

2016-01-01

Chlamydia trachomatis can enter a viable but nonculturable state in vitro termed persistence. A common feature of C. trachomatis persistence models is that reticulate bodies fail to divide and make few infectious progeny until the persistence-inducing stressor is removed. One model of persistence that has relevance to human disease involves tryptophan limitation mediated by the host enzyme indoleamine 2,3-dioxygenase, which converts l-tryptophan to N-formylkynurenine. Genital C. trachomatis strains can counter tryptophan limitation because they encode a tryptophan-synthesizing enzyme. Tryptophan synthase is the only enzyme that has been confirmed to play a role in interferon gamma (IFN-γ)-induced persistence, although profound changes in chlamydial physiology and gene expression occur in the presence of persistence-inducing stressors. Thus, we screened a population of mutagenized C. trachomatis strains for mutants that failed to reactivate from IFN-γ-induced persistence. Six mutants were identified, and the mutations linked to the persistence phenotype in three of these were successfully mapped. One mutant had a missense mutation in tryptophan synthase; however, this mutant behaved differently from previously described synthase null mutants. Two hypothetical genes of unknown function, ctl0225 and ctl0694, were also identified and may be involved in amino acid transport and DNA damage repair, respectively. Our results indicate that C. trachomatis utilizes functionally diverse genes to mediate survival during and reactivation from persistence in HeLa cells. PMID:27430273

Indoleamine 2,3-dioxygenase-dependent tryptophan metabolites contribute to tolerance induction during allergen immunotherapy in a mouse model.

PubMed

Taher, Yousef A; Piavaux, Benoit J A; Gras, Reneé; van Esch, Betty C A M; Hofman, Gerard A; Bloksma, Nanne; Henricks, Paul A J; van Oosterhout, Antoon J M

2008-04-01

The tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) has been implicated in immune suppression and tolerance induction. We examined (1) whether IDO activity is required during tolerance induction by allergen immunotherapy or for the subsequent suppressive effects on asthma manifestations and (2) whether tryptophan depletion or generation of its downstream metabolites is involved. Ovalbumin (OVA)-sensitized and OVA-challenged BALB/c mice that display increased airway responsiveness to methacholine, serum OVA-specific IgE levels, bronchoalveolar eosinophilia, and TH2 cytokine levels were used as a model of allergic asthma. Sensitized mice received subcutaneous optimal (1 mg) or suboptimal (100 microg) OVA immunotherapy. Inhibition of IDO by 1-methyl-DL-tryptophan during immunotherapy, but not during inhalation challenge, partially reversed the suppressive effects of immunotherapy on airway eosinophilia and TH2 cytokine levels, whereas airway hyperresponsiveness and serum OVA-specific IgE levels remained suppressed. Administration of tryptophan during immunotherapy failed to abrogate its beneficial effects toward allergic airway inflammation. Interestingly, administration of tryptophan or its metabolites, kynurenine, 3-hydroxykynurenine, and xanthurenic acid, but not 3-hydroxyanthranilinic acid, quinolinic acid, and kynurenic acid, during suboptimal immunotherapy potentiated the reduction of eosinophilia. These effects coincided with reduced TH2 cytokine levels in bronchoalveolar lavage fluid, but no effects on IgE levels were detected. During immunotherapy, the tryptophan metabolites kynurenine, 3-hydroxykynurenine, and xanthurenic acid generated through IDO contribute to tolerance induction regarding TH2-dependent allergic airway inflammation.

Increases in Plasma Tryptophan Are Inversely Associated with Incident Cardiovascular Disease in the Prevención con Dieta Mediterránea (PREDIMED) Study123

PubMed Central

Yu, Edward; Ruiz-Canela, Miguel; Guasch-Ferré, Marta; Zheng, Yan; Toledo, Estefania; Clish, Clary B; Salas-Salvadó, Jordi; Liang, Liming; Wang, Dong D; Corella, Dolores; Fitó, Montse; Gómez-Gracia, Enrique; Lapetra, José; Estruch, Ramón; Ros, Emilio; Cofán, Montserrat; Arós, Fernando; Romaguera, Dora; Serra-Majem, Lluis; Sorlí, Jose V; Hu, Frank B; Martinez-Gonzalez, Miguel A

2017-01-01

Background: During development of cardiovascular disease (CVD), interferon-γ–mediated inflammation accelerates degradation of tryptophan into downstream metabolites. A Mediterranean diet (MedDiet) consisting of a high intake of extra-virgin olive oil (EVOO), nuts, fruits, vegetables, and cereals has been demonstrated to lower the risk of CVD. The longitudinal relation between tryptophan and its downstream metabolites and CVD in the context of a MedDiet is unstudied. Objective: We sought to investigate the relation between metabolites in the tryptophan-kynurenine pathway and CVD in the context of a MedDiet pattern. Methods: We used a case-cohort design nested in the Prevención con Dieta Mediterránea randomized controlled trial. There were 231 CVD cases (stroke, myocardial infarction, cardiovascular death) among 985 participants over a median of 4.7 y of follow-up [mean ± SD age: 67.6 ± 6.1 y; 53.7% women; mean ± SD body mass index (in kg/m2): 29.7 ± 3.7]. We assessed plasma tryptophan, kynurenine, kynurenic acid, 3-hydroxyanthranilic acid, and quinolinic acid concentrations at baseline and after 1 y of intervention with a MedDiet. We combined these metabolites in a kynurenine risk score (KRS) by weighting each metabolite by the adjusted coefficient of its associations with CVD. Cox models were used in the primary analysis. Results: Increases in tryptophan after 1 y were associated with a lower risk of composite CVD (HR per SD: 0.79; 95% CI: 0.63, 0.98). The baseline kynurenic acid concentration was associated with a higher risk of myocardial infarction and coronary artery disease death but not stroke. A higher KRS was more strongly associated with CVD in the control group than in the 2 intervention groups (P-interaction = 0.003). Adjustment for changes in plasma tryptophan attenuated the inverse association between MedDiet+EVOO and CVD. Conclusions: An increase in the plasma tryptophan concentration was significantly associated with a decreased risk of CVD. A MedDiet may counteract the deleterious effects of a high tryptophan risk score. PMID:28179491

Spectroscopic characterization of Cu(II) complex of L-phenylalanine and D, L-tryptophan

NASA Astrophysics Data System (ADS)

Altun, Özlen; Bilcen, Selin

2010-02-01

In this work, the reactions involving L-phenylalanine and D, L-tryptophan in the presence of Cu(II) ion were studied. Optimum conditions for the reactions were established as pH 7 and λ = 641 nm. When the reaction was kinetic, it was observed that the following rate formula was found as dA/ An = k dt and k = 3.2 × 10 -4 s -1, according to absorbance measurements. Using a perpetual change curve, the ratio of [Cu]/[Cu] + L-phenylalanine + [ D, L-tryptophan] was found 1:1:1. According to this result, one molecule of L-phenylalanine and one molecule of D, L-tryptophan react with one molecule Cu(II) ion.

Endogenous strychnine: description of hypo- and hyperstrychninergic state in relation to neuropsychiatric diseases.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2002-10-01

Previous work from our laboratory has demonstrated the presence of endogenous strychnine in the mammalian brain and human serum samples. The present study examines the role of strychnine in neuropsychiatric disorders. Strychnine is synthesized from tryptophan. The blood levels of tyrosine, tryptophan, and strychnine were studied as also RBC membrane Na(+)-K+ ATPase activity. It was found that serum tyrosine levels were reduced and that tryptophan levels were elevated in all neuropsychiatric disorders studied with a reduction in RBC Na(+)-K+ ATPase activity. Strychnine was present in significant amounts in the serum of patients with epilepsy, Parkinson's disease, and manic depressive psychosis. The presence of strychnine in significant amounts could be related to elevated tryptophan levels, suggesting the synthesis of these alkaloids from tryptophan. Na(+)-K+ ATPase inhibition present in most of the disorders could be related to increased depolarizing strychninergic transmission. The role of strychnine in the pathogenesis of these disorders, in the setting of membrane Na(+)-K+ ATPase inhibition, is discussed.

Possible site-specific reagent for the general amino acid transport system of Saccharomyces cerevisiae.

PubMed

Larimore, F S; Roon, R J

1978-02-07

The general amino acid transport system of Saccharomyces cerevisiae functions in the uptake of neutral, basic, and acidic amino acids. The amino acid analogue N-delta-chloroacetyl-L-ornithine (NCAO) has been tested as potential site specific reagent for this system. L-Tryptophan, which is transported exclusively by the general transport system, was used as a substrate. In the presence of glucose as an energy source, NCAO inhibited tryptophan transport competitively (Ki = 80 micrometer) during short time intervals (1-2 min), but adding 100 micrometer NCAO to a yeast cell suspension resulted in a time-dependent activation of tryptophan transport during the first 15 min of treatment. Following the activation a time-dependent decay of tryptophan transport activity occurred. Approximately 80% inactivation of the system was observed after 90 min. When a yeast cell suspension was treated with NCAO in the absence of an energy source, an 80% inactivation of tryptophan transport occurred in 90 min. The inactivation was noncompetitive (Ki congruent to 60 micrometer) and could not be reversed by the removal of the NCAO. Addition of a five-fold excess of L-lysine during NCAO treatment or prevented inactivation of tryptophan transport. Under parallel conditions of incubation, other closely related transport systems were not inhibited by NCAO.

Double Tryptophan Exciton Probe to Gauge Proximal Side Chains in Proteins- Augmentation at Low Temperature

PubMed Central

Gasymov, Oktay K.; Abduragimov, Adil R.; Glasgow, Ben J.

2015-01-01

The circular dichroic (CD) exciton couplet between tryptophans and/or tyrosines offers the potential to probe distances within 10Å in proteins. The exciton effect has been used with native chromophores in critical positions in a few proteins. Here, site-directed mutagenesis created double tryptophan probes for key sites of a protein (tear lipocalin). For tear lipocalin the crystal and solution structures are concordant in both apo- and holo-forms. Double tryptophan substitutions were performed at sites that could probe conformation and were likely within 10 Å. Far-UV CD spectra of double Trp mutants were performed with controls that had non-interacting substituted tryptophans. Low temperature (77K) was tested for augmentation of the exciton signal. Exciton coupling appeared with tryptophan substitutions at positions within loop A-B (28 and 31, 33), between loop A-B (28) and strand G (103 and 105), as well as between the strands B (35) and C (56). The CD exciton couplet signals were amplified 3–5 fold at 77K. The results were concordant with close distances in crystal and solution structures. The exciton couplets had functional significance and correctly assigned the holo-conformation. The methodology creates an effective probe to identify proximal amino acids in a variety of motifs. PMID:25693116

Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

PubMed

Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

Nature of autofluorescence in human serum albumin under its native, unfolding and digested forms

NASA Astrophysics Data System (ADS)

Manjunath, S.; Rao, Bola Sadashiva Satish; Satyamoorthy, Kapaettu; Mahato, Krishna Kishore

2014-02-01

Autofluorescence characteristics of human serum albumin (HSA) are highly sensitive to its local environment. Identification and characterization of the proteins in normal and disease conditions may have great clinical implications. Aim of the present study was to understand how autofluorescence properties of HSA varies with denaturation under urea (3.0M, 6.0M, 9.0M) and guanidine hydrochloride (GnHCl) (2.0M, 4.0M, 6.0M) as well as digestion with trypsin. Towards this, we have recorded the corresponding autofluorescence spectra of HSA at 281nm laser excitation and compared the outcomes. Although, HSA contains 1 tryptophan and 17 tyrosine residues, it has shown intense autofluorescence due to tryptophan as compared to the tyrosine in native form, which may be due to the fluorescence resonance energy transfer (FRET) from tyrosine to tryptophan. As the unfolding progresses in denatured and digested forms of the protein, a clear increase in tyrosine fluorescence as compared to tryptophan was observed, which may be due to the increase of tryptophan - tyrosine separation disturbing the FRET between them resulting in differences in the overall autofluorescence properties. The decrease in tryptophan fluorescence of around 17% in urea denatured, 32% in GnHCl denatured and 96% in tryptic digested HSA was observed as compared to its native form. The obtained results show a clear decrease in FRET between tyrosine and tryptophan residues with the progression of unfolding and urea seems to be less efficient than GnHCl in unfolding of HSA. These results demonstrate the potential of autofluorescence in characterizing proteins in general and HSA in particular.

Serotonergic Contribution to Boys' Behavioral Regulation

PubMed Central

Nantel-Vivier, Amélie; Young, Simon N.; Parent, Sophie; Bélanger, Stacey Ageranioti; Sutton, Rachel; Dubois, Marie-Eve

2011-01-01

Objectives Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure. Method Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered. Results Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter. Conclusions The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors. PMID:21673801

Tryptophan Scanning Reveals Dense Packing of Connexin Transmembrane Domains in Gap Junction Channels Composed of Connexin32.

PubMed

Brennan, Matthew J; Karcz, Jennifer; Vaughn, Nicholas R; Woolwine-Cunningham, Yvonne; DePriest, Adam D; Escalona, Yerko; Perez-Acle, Tomas; Skerrett, I Martha

2015-07-10

Tryptophan was substituted for residues in all four transmembrane domains of connexin32. Function was assayed using dual cell two-electrode voltage clamp after expression in Xenopus oocytes. Tryptophan substitution was poorly tolerated in all domains, with the greatest impact in TM1 and TM4. For instance, in TM1, 15 substitutions were made, six abolished coupling and five others significantly reduced function. Only TM2 and TM3 included a distinct helical face that lacked sensitivity to tryptophan substitution. Results were visualized on a comparative model of Cx32 hemichannel. In this model, a region midway through the membrane appears highly sensitive to tryptophan substitution and includes residues Arg-32, Ile-33, Met-34, and Val-35. In the modeled channel, pore-facing regions of TM1 and TM2 were highly sensitive to tryptophan substitution, whereas the lipid-facing regions of TM3 and TM4 were variably tolerant. Residues facing a putative intracellular water pocket (the IC pocket) were also highly sensitive to tryptophan substitution. Although future studies will be required to separate trafficking-defective mutants from those that alter channel function, a subset of interactions important for voltage gating was identified. Interactions important for voltage gating occurred mainly in the mid-region of the channel and focused on TM1. To determine whether results could be extrapolated to other connexins, TM1 of Cx43 was scanned revealing similar but not identical sensitivity to TM1 of Cx32. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Effects of Intragastric Administration of Tryptophan on the Blood Glucose Response to a Nutrient Drink and Energy Intake, in Lean and Obese Men.

PubMed

Ullrich, Sina S; Fitzgerald, Penelope C E; Giesbertz, Pieter; Steinert, Robert E; Horowitz, Michael; Feinle-Bisset, Christine

2018-04-08

Tryptophan stimulates plasma cholecystokinin and pyloric pressures, both of which slow gastric emptying. Gastric emptying regulates postprandial blood glucose. Tryptophan has been reported to decrease energy intake. We investigated the effects of intragastric tryptophan on the glycaemic response to, and gastric emptying of, a mixed-nutrient drink, and subsequent energy intake. Lean and obese participants ( n = 16 each) received intragastric infusions of 1.5 g ("Trp-1.5g") or 3.0 g ("Trp-3.0g") tryptophan, or control, and 15 min later consumed a mixed-nutrient drink (56 g carbohydrates). Gastric emptying ( 13 C-acetate breath-test), blood glucose, plasma C-peptide, glucagon, cholecystokinin and tryptophan concentrations were measured ( t = 0-60 min). Energy intake was assessed between t = 60-90 min. In lean individuals, Trp-3.0g, but not Trp-1.5g, slowed gastric emptying, reduced C-peptide AUC and increased glucagon AUC (all P < 0.05), but did not significantly decrease the blood glucose response to the drink, stimulate cholecystokinin or reduce mean energy intake, compared with control. In obese individuals, Trp-3.0g, but not Trp-1.5g, tended to slow gastric emptying ( P = 0.091), did not affect C-peptide AUC , increased glucagon AUC ( P < 0.001) and lowered blood glucose at t = 30 min ( P < 0.05), and did not affect cholecystokinin or mean energy intake. In obese individuals, intragastrically administered tryptophan may reduce postprandial blood glucose by slowing gastric emptying; the lack of effect on mean energy intake requires further investigation.

Gene modification of the acetate biosynthesis pathway in Escherichia coli and implementation of the cell recycling technology to increase L-tryptophan production

PubMed Central

Bai, Fang; Chen, Ning; Bai, Gang

2017-01-01

The implementation of a novel cell recycling technology based on a special disk centrifuge during microbial fermentation process can continuously separate the product and harmful intermediates, while maintaining the cell viability owing to the installed cooling system. Acetate accumulation is an often encountered problem in L-tryptophan fermentation by Escherichia coli. To extend our previous studies, the current study deleted the key genes underlying acetate biosynthesis to improve l-tryptophan production. The deletion of the phosphotransacetylase (pta)–acetate kinase (ackA) pathway in a gltB (encoding glutamate synthase) mutant of E. coli TRTHB, led to the highest production of l-tryptophan (47.18 g/L) and glucose conversion rate (17.83%), with a marked reduction in acetate accumulation (1.22 g/L). This strain, TRTHBPA, was then used to investigate the effects of the cell recycling process on L-tryptophan fermentation. Four different strategies were developed concerning two issues, the volume ratio of the concentrated cell solution and clear solution and the cell recycling period. With strategy I (concentrated cell solution: clear solution, 1: 1; cell recycling within 24–30 h), L-tryptophan production and the glucose conversion rate increased to 55.12 g/L and 19.75%, respectively, 17.55% and 10.77% higher than those without the cell recycling. In addition, the biomass increased by 13.52% and the fermentation period was shortened from 40 h to 32 h. These results indicated that the cell recycling technology significantly improved L-tryptophan production by E. coli. PMID:28622378

Extrinsic Tryptophans as NMR Probes of Allosteric Coupling in Membrane Proteins: Application to the A2A Adenosine Receptor.

PubMed

Eddy, Matthew T; Gao, Zhan-Guo; Mannes, Philip; Patel, Nilkanth; Jacobson, Kenneth A; Katritch, Vsevolod; Stevens, Raymond C; Wüthrich, Kurt

2018-06-20

Tryptophan indole 15 N- 1 H signals are well separated in nuclear magnetic resonance (NMR) spectra of proteins. Assignment of the indole 15 N- 1 H signals therefore enables one to obtain site-specific information on complex proteins in supramacromolecular systems, even when extensive assignment of backbone 15 N- 1 H resonances is challenging. Here we exploit the unique indole 15 N- 1 H chemical shift by introducing extrinsic tryptophan reporter residues at judiciously chosen locations in a membrane protein for increased coverage of structure and function by NMR. We demonstrate this approach with three variants of the human A 2A adenosine receptor (A 2A AR), a class A G protein-coupled receptor, each containing a single extrinsic tryptophan near the receptor intracellular surface, in helix V, VI, or VII, respectively. We show that the native A 2A AR global protein fold and ligand binding activity are preserved in these A 2A AR variants. The indole 15 N- 1 H signals from the extrinsic tryptophan reporter residues show different responses to variable efficacy of drugs bound to the receptor orthosteric cavity, and the indole 15 N- 1 H chemical shift of the tryptophan introduced at the intracellular end of helix VI is sensitive to conformational changes resulting from interactions with a polypeptide from the carboxy terminus of the Gα S intracellular partner protein. Introducing extrinsic tryptophans into proteins in complex supramolecular systems thus opens new avenues for NMR investigations in solution.

Effect of diet on serotonergic neurotransmission in depression.

PubMed

Shabbir, Faisal; Patel, Akash; Mattison, Charles; Bose, Sumit; Krishnamohan, Raathathulaksi; Sweeney, Emily; Sandhu, Sarina; Nel, Wynand; Rais, Afsha; Sandhu, Ranbir; Ngu, Nguasaah; Sharma, Sushil

2013-02-01

Depression is characterized by sadness, purposelessness, irritability, and impaired body functions. Depression causes severe symptoms for several weeks, and dysthymia, which may cause chronic, low-grade symptoms. Treatment of depression involves psychotherapy, medications, or phototherapy. Clinical and experimental evidence indicates that an appropriate diet can reduce symptoms of depression. The neurotransmitter, serotonin (5-HT), synthesized in the brain, plays an important role in mood alleviation, satiety, and sleep regulation. Although certain fruits and vegetables are rich in 5-HT, it is not easily accessible to the CNS due to blood brain barrier. However the serotonin precursor, tryptophan, can readily pass through the blood brain barrier. Tryptophan is converted to 5-HT by tryptophan hydroxylase and 5-HTP decarboxylase, respectively, in the presence of pyridoxal phosphate, derived from vitamin B(6). Hence diets poor in tryptophan may induce depression as this essential amino acid is not naturally abundant even in protein-rich foods. Tryptophan-rich diet is important in patients susceptible to depression such as certain females during pre and postmenstrual phase, post-traumatic stress disorder, chronic pain, cancer, epilepsy, Parkinson's disease, Alzheimer's disease, schizophrenia, and drug addiction. Carbohydrate-rich diet triggers insulin response to enhance the bioavailability of tryptophan in the CNS which is responsible for increased craving of carbohydrate diets. Although serotonin reuptake inhibitors (SSRIs) are prescribed to obese patients with depressive symptoms, these agents are incapable of precisely regulating the CNS serotonin and may cause life-threatening adverse effects in the presence of monoamine oxidase inhibitors. However, CNS serotonin synthesis can be controlled by proper intake of tryptophan-rich diet. This report highlights the clinical significance of tryptophan-rich diet and vitamin B(6) to boost serotonergic neurotransmission in depression observed in various neurodegenerative diseases. However pharmacological interventions to modulate serotonergic neurotransmission in depression, remains clinically significant. Depression may involve several other molecular mechanisms as discussed briefly in this report. Copyright © 2012 Elsevier Ltd. All rights reserved.

Peripheral Serotonin 1B Receptor Transcription Predicts the Effect of Acute Tryptophan Depletion on Risky Decision-Making.

PubMed

Faulkner, Paul; Mancinelli, Federico; Lockwood, Patricia L; Matarin, Mar; Dolan, Raymond J; Wood, Nick W; Dayan, Peter; Roiser, Jonathan P

2017-01-01

The effects of acute tryptophan depletion on human decision-making suggest that serotonin modulates the processing of rewards and punishments. However, few studies have assessed which of the many types of serotonin receptors are responsible. Using a within-subject, double-blind, sham-controlled design in 26 subjects, we examined whether individual differences in serotonin system gene transcription, measured in peripheral blood, predicted the effect of acute tryptophan depletion on decision-making. Participants performed a task in which they chose between successive pairs of fixed, lower-stakes (control) and variable, higher-stakes (experimental) gambles, each involving wins or losses. In 21 participants, mRNA from 9 serotonin system genes was measured in whole blood prior to acute tryptophan depletion: 5-HT1B, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, 5-HT3E, 5-HT7 (serotonin receptors), 5-HTT (the serotonin transporter), and tryptophan hydroxylase 1. Acute tryptophan depletion did not significantly influence participants' sensitivity to probability, wins, or losses, although there was a trend for a lower tendency to choose experimental gambles overall following depletion. Significant positive correlations, which survived correction for multiple comparisons, were detected between baseline 5-HT1B mRNA levels and acute tryptophan depletion-induced increases in both the overall tendency to choose the experimental gamble and sensitivity to wins. No significant relationship was observed with any other peripheral serotonin system markers. Computational analyses of decision-making data provided results consistent with these findings. These results suggest that the 5-HT1B receptor may modulate the effects of acute tryptophan depletion on risky decision-making. Peripheral levels of serotonin markers may predict response to treatments that act upon the serotonin system, such as selective serotonin reuptake inhibitors. © The Author 2016. Published by Oxford University Press on behalf of CINP.

Age-related changes in the thermoregulatory capacity of tryptophan-deficient rats.

PubMed

Segall, P E; Timiras, P S

1975-01-01

From a larger study seeking to develop indexes of physiological aging, the present experiment was designed 1) to test thermoregulatory capacity in the aging and old rat subjected to 3 minutes of whole-body ice water immersion, and 2) using this index of physiological age, to determine whether tryptophan deficiency from time of weaning can retard the onset of senescence. Results indicate a progressive prolongation of temperature recovery time from young to middle age to old, and tryptophan-deficient animals restored to commercial diet at middle age show the thermoregulatory capacity of young adults. The implications of tryptophan deficiency with respect to brain development, serotonin metabolism, and temperature regulation are also discussed in terms of the possibility of intervening with the aging process.

Maintenance valine, isoleucine, and tryptophan requirements for poultry.

PubMed

de Lima, M B; Sakomura, N K; Dorigam, J C P; da Silva, E P; Ferreira, N T; Fernandes, J B K

2016-04-01

Poultry maintenance requirements for valine, isoleucine, and tryptophan were measured by nitrogen balance using different unit systems. The nitrogen balance trial lasted 5 d with 48 h of fasting (with roosters receiving only water+sucrose) and the last 72 h for feeding and excreta collection. Forty grams of each diet first-limiting in valine, isoleucine, or tryptophan was fed by tube each day (3 d) to give a range of intakes from 0 to 101, 0 to 119, and 0 to 34 mg/kg BW d of valine, isoleucine, and tryptophan, respectively. A nitrogen-free diet containing energy, vitamins, and minerals, meeting the rooster requirements, was offered ad libitum during these three d. To confirm that the amino acids studied were limiting, a treatment was added with a control diet formulated by adding 0.24 g/kg of L-valine, 0.21 g/kg of L-isoleucine, and 0.10 g/kg of L-tryptophan to the diets with lower amino acid level. Excreta were collected during the last 3 d of the balance period and the nitrogen content of the excreta was analyzed. For each amino acid, a linear regression between nitrogen retention (NR) and amino acid intake was performed. The equations from linear regression were: NR=-98.6 (±10.1)+2.4 (±0.2)×Val, NR=-46.9 (±7.1)+2.3 (±0.1)×Ile, NR=-39.5 (±7.7)+7.3 (±0.4)×Trp; where Val, Ile, and Trp are the intakes of valine, isoleucine, and tryptophan in mg/kg body weight per d, respectively. The valine, isoleucine, and tryptophan required to maintain the body at zero NR were calculated to be 41, 20, and 5 mg/kg body weight per d, respectively. For the system unit mg per kg of metabolic weight, the intake of valine, isoleucine, and tryptophan was 59, 32, and 9, respectively. Considering the degree of maturity of the animal and body protein content (BPm (0.73)×u), the amounts of valine, isoleucine, and tryptophan required for maintenance were calculated to be 247, 134, and 37 mg per unit of maintenance protein (BPm (0.73)×u) per d. Maintenance requirement is more adequately expressed as body protein content. © 2016 Poultry Science Association Inc.

Tryptophan, thiamine and indole-3-acetic acid exchange between Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense.

PubMed

Palacios, Oskar A; Gomez-Anduro, Gracia; Bashan, Yoav; de-Bashan, Luz E

2016-06-01

During synthetic mutualistic interactions between the microalga Chlorella sorokiniana and the plant growth-promoting bacterium (PGPB) Azospirillum brasilense, mutual exchange of resources involved in producing and releasing the phytohormone indole-3-acetic acid (IAA) by the bacterium, using tryptophan and thiamine released by the microalga, were measured. Although increased activities of tryptophan synthase in C. sorokiniana and indole pyruvate decarboxylase (IPDC) in A. brasilense were observed, we could not detect tryptophan or IAA in the culture medium when both organisms were co-immobilized. This indicates that no extra tryptophan or IAA is produced, apart from the quantities required to sustain the interaction. Over-expression of the ipdC gene occurs at different incubation times: after 48 h, when A. brasilense was immobilized alone and grown in exudates of C. sorokiniana and at 96 h, when A. brasilense was co-immobilized with the microalga. When A. brasilense was cultured in exudates of C. sorokiniana, increased expression of the ipdC gene, corresponding increase in activity of IPDC encoded by the ipdC gene, and increase in IAA production were measured during the first 48 h of incubation. IAA production and release by A. brasilense was found only when tryptophan and thiamine were present in a synthetic growth medium (SGM). The absence of thiamine in SGM yielded no detectable IAA. In summary, this study demonstrates that C. sorokiniana can exude sufficient tryptophan and thiamine to allow IAA production by a PGPB during their interaction. Thiamine is essential for IAA production by A. brasilense and these three metabolites are part of a communication between the two microorganisms. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tryptophan-kynurenine and lipid related metabolites as blood biomarkers for first-episode drug-naïve patients with major depressive disorder: An exploratory pilot case-control study.

PubMed

Kuwano, Nobuki; Kato, Takahiro A; Setoyama, Daiki; Sato-Kasai, Mina; Shimokawa, Norihiro; Hayakawa, Kohei; Ohgidani, Masahiro; Sagata, Noriaki; Kubo, Hiroaki; Kishimoto, Junji; Kang, Dongchon; Kanba, Shigenob

2018-04-15

Early intervention in depression has been critical to prevent its negative impact including suicide. Recent blood biomarker studies for major depressive disorder (MDD) have suggested that tryptophan-kynurenine and lipid related metabolites are involved in the pathophysiology of MDD. However, there have been limited studies investigating these blood biomarkers in first-episode drug-naïve MDD, which are particularly important for early intervention in depression. As an exploratory pilot case-control study, we examined the above blood biomarkers, and analyzed how these biomarkers are associated with clinical variables in first-episode drug-naïve MDD patients, based on metabolome/lipidome analysis. Plasma tryptophan and kynurenine levels were significantly lower in MDD group (N = 15) compared to healthy controls (HC) group (N = 19), and plasma tryptophan was the significant biomarker to identify MDD group (area under the curve = 0.740). Lower serum high density lipoprotein-cholesterol (HDL-C) was the predictive biomarker for severity of depression in MDD group (R 2 = 0.444). Interestingly, depressive symptoms were variously correlated with plasma tryptophan-kynurenine and lipid related metabolites. Moreover, plasma tryptophan-kynurenine metabolites and cholesteryl esters (CEs) were significantly correlated in MDD group, but not in HC group. This study had small sample size, and we did not use the multiple test correction. This is the first study to suggest that not only tryptophan-kynurenine metabolites but also HDL-C and CEs are important blood biomarkers for first-episode drug-naïve MDD patients. The present study sheds new light on early intervention in clinical practice in depression, and further clinical studies especially large-scale prospective studies are warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

Whey protein rich in alpha-lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects.

PubMed

Markus, C Rob; Olivier, Berend; de Haan, Edward H F

2002-06-01

Cognitive performance often declines under chronic stress exposure. The negative effect of chronic stress on performance may be mediated by reduced brain serotonin function. The uptake of the serotonin precursor tryptophan into the brain depends on nutrients that influence the availability of tryptophan by changing the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp-LNAA ratio). In addition, a diet-induced increase in tryptophan may increase brain serotonergic activity levels and improve cognitive performance, particularly in high stress-vulnerable subjects. We tested whether alpha-lactalbumin, a whey protein with a high tryptophan content, would increase the plasma Trp-LNAA ratio and improve cognitive performance in high stress- vulnerable subjects. Twenty-three high stress-vulnerable subjects and 29 low stress-vulnerable subjects participated in a double-blind, placebo-controlled, crossover study. All subjects conducted a memory-scanning task after the intake of a diet enriched with either alpha-lactalbumin (alpha-lactalbumin diet) or sodium caseinate (control diet). Blood samples were taken to measure the effect of dietary manipulation on the plasma Trp-LNAA ratio. A significantly greater increase in the plasma Trp-LNAA ratio after consumption of the alpha-lactalbumin diet than after the control diet (P = 0.0001) was observed; memory scanning improved significantly only in the high stress-vulnerable subjects (P = 0.019). Because an increase in the plasma Trp-LNAA ratio is considered to be an indirect indication of increased brain serotonin function, the results suggest that dietary protein rich in alpha-lactalbumin improves cognitive performance in stress-vulnerable subjects via increased brain tryptophan and serotonin activities.

Copolymers of poly-L-lysine with serine and tryptophan form stable DNA vectors: implications for receptor-mediated gene transfer.

PubMed

Gómez-Valadés, A G; Molas, M; Vidal-Alabró, A; Bermúdez, J; Bartrons, R; Perales, J C

2005-01-20

Inefficient gene transfer and poor stability in physiological medium are important shortcomings for receptor-mediated gene transfer vectors. Here, we evaluate vectors formulated with random copolymers of L-lysine/L-serine (3:1) and L-lysine/L-tryptophan (4:1), focusing on both their biophysical and functional characterization. By means of dynamic light scattering (DLS) and transmission electron microscopy (TEM), we demonstrate that poly-L-lysine (pK), poly-L-lysine-L-tryptophan (pKW) and poly-L-lysine-L-serine (pKS) are able to form compacted, small particles when mixed with plasmid DNA in the absence of salt. Upon dilution in physiological medium, copolymers of both lys/ser and lys/trp do not aggregate, in contrast with poly-L-lysine DNA complexes as determined by scattering, DLS and TEM measurements. Tight packing, as demonstrated by resistance to heparin, SDS and trypsin treatments, is also featured in tryptophan-containing complexes. Successful receptor-mediated endocytosis gene transfer using galactosylated copolymers into cells expressing the asiagloglycoprotein receptor correlated with lack of aggregation. Particles obtained using galactosylated poly-L-lysine-L-tryptophan (Gal-pKW) copolymer demonstrated specific receptor-mediated gene transfer since reporter gene activity dropped in the presence of an excess ligand in the culture medium during transfection. Although copolymers of galactosylated poly-L-lysine-L-serine (Gal-pKS) do not aggregate in the presence of salt, they are not able to internalize in a specific receptor-mediated endocytosis fashion. The introduction of bulky aromatic/hydrophobic (tryptophan) or hydrophillic (serine) moieties into the positively charged vectors allows the compacted particles to disperse into salt-containing medium avoiding salt-induced aggregation. Moreover, tryptophan-containing particles are able to mediate specific gene transfer via receptor-mediated endocytosis.

Tryptophan depletion decreases the recognition of fear in female volunteers.

PubMed

Harmer, C J; Rogers, R D; Tunbridge, E; Cowen, P J; Goodwin, G M

2003-06-01

Serotonergic processes have been implicated in the modulation of fear conditioning in humans, postulated to occur at the level of the amygdala. The processing of other fear-relevant cues, such as facial expressions, has also been associated with amygdala function, but an effect of serotonin depletion on these processes has not been assessed. The present study investigated the effects of reducing serotonin function, using acute tryptophan depletion, on the recognition of basic facial expressions of emotions in healthy male and female volunteers. A double-blind between-groups design was used, with volunteers being randomly allocated to receive an amino acid drink specifically lacking tryptophan or a control mixture containing a balanced mixture of these amino acids. Participants were given a facial expression recognition task 5 h after drink administration. This task featured examples of six basic emotions (fear, anger, disgust, surprise, sadness and happiness) that had been morphed between each full emotion and neutral in 10% steps. As a control, volunteers were given a famous face classification task matched in terms of response selection and difficulty level. Tryptophan depletion significantly impaired the recognition of fearful facial expressions in female, but not male, volunteers. This was specific since recognition of other basic emotions was comparable in the two groups. There was also no effect of tryptophan depletion on the classification of famous faces or on subjective state ratings of mood or anxiety. These results confirm a role for serotonin in the processing of fear related cues, and in line with previous findings also suggest greater effects of tryptophan depletion in female volunteers. Although acute tryptophan depletion does not typically affect mood in healthy subjects, the present results suggest that subtle changes in the processing of emotional material may occur with this manipulation of serotonin function.

Influence of the tryptophan-indole-IFNγ axis on human genital Chlamydia trachomatis infection: role of vaginal co-infections.

PubMed

Aiyar, Ashok; Quayle, Alison J; Buckner, Lyndsey R; Sherchand, Shardulendra P; Chang, Theresa L; Zea, Arnold H; Martin, David H; Belland, Robert J

2014-01-01

The natural history of genital Chlamydia trachomatis infections can vary widely; infections can spontaneously resolve but can also last from months to years, potentially progressing to cause significant pathology. The host and bacterial factors underlying this wide variation are not completely understood, but emphasize the bacterium's capacity to evade/adapt to the genital immune response, and/or exploit local environmental conditions to survive this immune response. IFNγ is considered to be a primary host protective cytokine against endocervical C. trachomatis infections. IFNγ acts by inducing the host enzyme indoleamine 2,3-dioxgenase, which catabolizes tryptophan, thereby depriving the bacterium of this essential amino acid. In vitro studies have revealed that tryptophan deprivation causes Chlamydia to enter a viable but non-infectious growth pattern that is termed a persistent growth form, characterized by a unique morphology and gene expression pattern. Provision of tryptophan can reactivate the bacterium to the normal developmental cycle. There is a significant difference in the capacity of ocular and genital C. trachomatis serovars to counter tryptophan deprivation. The latter uniquely encode a functional tryptophan synthase to synthesize tryptophan via indole salvage, should indole be available in the infection microenvironment. In vitro studies have confirmed the capacity of indole to mitigate the effects of IFNγ; it has been suggested that a perturbed vaginal microbiome may provide a source of indole in vivo. Consistent with this hypothesis, the microbiome associated with bacterial vaginosis includes species that encode a tryptophanase to produce indole. In this review, we discuss the natural history of genital chlamydial infections, morphological and molecular changes imposed by IFNγ on Chlamydia, and finally, the microenvironmental conditions associated with vaginal co-infections that can ameliorate the effects of IFNγ on C. trachomatis.

Immunomodulatory properties of cacao extracts – potential consequences for medical applications

PubMed Central

Becker, Kathrin; Geisler, Simon; Ueberall, Florian; Fuchs, Dietmar; Gostner, Johanna M.

2013-01-01

Anti-inflammatory properties of cacao, fruits of Theobroma cacao L. (Sterculiaceae), are well documented, and therapeutic applications are described for gastrointestinal, nervous, and cardiovascular abnormalities. Most, if not all of these disease conditions involve inflammation or immune activation processes. The pro-inflammatory cytokine interferon-γ (IFN-γ) and related biochemical pathways like tryptophan breakdown by indoleamine 2,3-dioxygenase (IDO) and neopterin formation are deeply involved in their pathogenesis. Neopterin concentrations and the kynurenine to tryptophan ratio (Kyn/Trp, an estimate of IDO activity) are elevated in a significant proportion of patients with virus infections, cancer, autoimmune syndrome, neurodegeneration, and coronary artery disease. Moreover, higher neopterin and Kyn/Trp concentrations are indicative for poor prognosis. When investigating the effect of aqueous or ethanolic extracts of cacao on IFN-γ, neopterin and Kyn/Trp concentrations in mitogen-stimulated human peripheral blood mononuclear cells, breakdown of tryptophan by IDO, and formation of neopterin and IFN-γ were dose-dependently suppressed. The effects observed in the cell-based assays are associated with the antioxidant activity of the cacao extracts as determined by the cell-free oxygen radical absorption capacity assay. The influence of cacao extracts on IDO activity could be of particular relevance for some of the beneficial health effects ascribed to cacao: tryptophan breakdown by IDO is strongly involved in immunoregulation, and the diminished availability of tryptophan limits the biosynthesis of neurotransmitter serotonin. The inhibition of tryptophan breakdown by cacao constituents could thus be relevant not only for immune system restoration in patients, but also contribute to mood elevation and thereby improve quality of life. However, the available data thus far are merely in vitro only and future studies need to investigate the influence of cacao on tryptophan metabolism in vivo. PMID:24376420

Fluorescence studies on native and bound to trifluraline soy bean Lb"a" in the enhanced N2 fixation.

PubMed

Kolev, K; Dolashka-Angelova, P

2001-10-01

The differences in the tryptophan (Trp) fluorescence of native (control) Lb"a" and experimental substance isolated from nodules of the Williams' soy beans variety treated with trifluraline at a concentration of 2.1 x 10(-10) M have been studied. A positively charged environment has been proved for the tryptophans of the native Lb"a" and a negative one for the tryptophans of the experimental Lb"a". The difference in the tryptophan emission spectra at lambdaex = 280 and 300 nm may be assigned to conformational alterations occurring in the experimental Lb"a". This is also confirmed by the greater energy transfer from tyrosine to tryptophan in the experimental Lb"a"--30% compared to the 10% in the native Lb"a". The value of the constant of acrylamide quenching (Ksv = 2.77 M(-1)) shows that the tryptophans are buried more deeply in the experimental Lb"a" than in the native Lb"a" (Ksv = 4 M(-1)). They are substantially lower than Ksv of the standard compound N-Ac-Trp-NH2 (16.30 M(-1)). The activation energy (Ea) of the thermal quenching of tryptophan fluorescence is higher for the experimental Lb"a" (37 kJ mol(-1)) as compared to the standard compound N-Ac-Trp-NH2 (24 kJ mol(-1)) and the native Lb "a" (32 kJ mol(-1)). The dissociation constant of the complex of trifluraline with Lb "a" (6.32 x 10(-11) M) has been determined as well as the stoichiometric ratio trifluraline/Lb"a" (1:1). The estimated nitrogenase activity (microM/gfrw h) and the total Lb (mg/gfrw) for trifluraline are higher as compared to those for the control.

Fluorescence studies on native and bound to trifluraline soy bean Lb "a" in the enhanced N 2 fixation

NASA Astrophysics Data System (ADS)

Kolev, Kolyo; Dolashka-Angelova, Pavlina

2001-10-01

The differences in the tryptophan (Trp) fluorescence of native (control) Lb "a" and experimental substance isolated from nodules of the 'Williams' soy beans variety treated with trifluraline at a concentration of 2.1×10 -10 M have been studied. A positively charged environment has been proved for the tryptophans of the native Lb "a" and a negative one for the tryptophans of the experimental Lb "a". The difference in the tryptophan emission spectra at λex=280 and 300 nm may be assigned to conformational alterations occurring in the experimental Lb "a". This is also confirmed by the greater energy transfer from tyrosine to tryptophan in the experimental Lb "a"—30% compared to the 10% in the native Lb "a". The value of the constant of acrylamide quenching ( Ksv=2.77 M -1) shows that the tryptophans are buried more deeply in the experimental Lb "a" than in the native Lb "a" ( Ksv=4 M -1). They are substantially lower than Ksv of the standard compound N-Ac-Trp-NH 2 (16.30 M -1). The activation energy ( Ea) of the thermal quenching of tryptophan fluorescence is higher for the experimental Lb "a" (37 kJ mol -1) as compared to the standard compound N-Ac-Trp-NH 2 (24 kJ mol -1) and the native Lb "a" (32 kJ mol -1). The dissociation constant of the complex of trifluraline with Lb "a" (6.32×10 -11 M) has been determined as well as the stoichiometric ratio trifluraline/Lb "a" (1:1). The estimated nitrogenase activity (μM/gfrw h) and the total Lb (mg/gfrw) for trifluraline are higher as compared to those for the control.

Pigment Production on L-Tryptophan Medium by Cryptococcus gattii and Cryptococcus neoformans

PubMed Central

Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin. PMID:24736553

Comparative effects of wild type Stenotrophomonas maltophilia and its indole acetic acid-deficient mutants on wheat.

PubMed

Hassan, T U; Bano, A

2016-09-01

The present investigation evaluated the role of Stenotrophomonas maltophilia and its IAA-deficient mutant on soil health and plant growth under salinity stress in the presence of tryptophan. In the first phase, S. maltophilia isolated from roots of the halo- phytic herb, Cenchrus ciliaris was used as bio-inoculant on wheat grown in saline sodic soil. A field experiment was conducted at Soil Salinity Research Institute during 2010-2011. Treatments included seed inoculation with S. maltophilia with or without tryptophan; uninoculated untreated plants were taken as control. An aqueous solution of tryptophan was added to rhizosphere soil at 1 μg l(_1) after seed germination. Inoculation with S. maltophilia significantly increased soil organic matter, enhanced (20-30%) availability of P, K, Ca and NO3 -N and decreased Na content and electrical conductivity of rhizosphere soil. Plant height, fresh weight, proline and phytohormone content of leaves were increased 30-40% over the control. Activities of superoxide dismutase (SOD) and peroxidase (POD) were 40-50% higher than control. Addition of tryptophan further augmented (10-15%) growth parameters, whereas NO3 -N, P, K and Ca content, proline content and SOD and POD increased 20-30%. In a second phase, indoleacetic acid (IAA)-deficient mutants of S. maltophilia were constructed and evaluated for conversion of tryptophan to IAA at the University of Calgary, Canada, during 2013-2014. About 1800 trans-conjugants were constructed that were unable to produce IAA in the presence of tryptophan. The results suggest that tryptophan assisted S. maltophilia in the amelioration of salt stress, and that IAA played positive role in induction of salt tolerance. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effects of Intragastric Administration of Tryptophan on the Blood Glucose Response to a Nutrient Drink and Energy Intake, in Lean and Obese Men

PubMed Central

Ullrich, Sina S.; Fitzgerald, Penelope C. E.; Giesbertz, Pieter; Steinert, Robert E.; Horowitz, Michael; Feinle-Bisset, Christine

2018-01-01

Tryptophan stimulates plasma cholecystokinin and pyloric pressures, both of which slow gastric emptying. Gastric emptying regulates postprandial blood glucose. Tryptophan has been reported to decrease energy intake. We investigated the effects of intragastric tryptophan on the glycaemic response to, and gastric emptying of, a mixed-nutrient drink, and subsequent energy intake. Lean and obese participants (n = 16 each) received intragastric infusions of 1.5 g (“Trp-1.5g”) or 3.0 g (“Trp-3.0g”) tryptophan, or control, and 15 min later consumed a mixed-nutrient drink (56 g carbohydrates). Gastric emptying (13C-acetate breath-test), blood glucose, plasma C-peptide, glucagon, cholecystokinin and tryptophan concentrations were measured (t = 0–60 min). Energy intake was assessed between t = 60–90 min. In lean individuals, Trp-3.0g, but not Trp-1.5g, slowed gastric emptying, reduced C-peptideAUC and increased glucagonAUC (all P < 0.05), but did not significantly decrease the blood glucose response to the drink, stimulate cholecystokinin or reduce mean energy intake, compared with control. In obese individuals, Trp-3.0g, but not Trp-1.5g, tended to slow gastric emptying (P = 0.091), did not affect C-peptideAUC, increased glucagonAUC (P < 0.001) and lowered blood glucose at t = 30 min (P < 0.05), and did not affect cholecystokinin or mean energy intake. In obese individuals, intragastrically administered tryptophan may reduce postprandial blood glucose by slowing gastric emptying; the lack of effect on mean energy intake requires further investigation. PMID:29642492

[Changes in cerebra serotonin synthesis induced by insulin-dependent diabetes mellitus].

PubMed

Manjarrez-Gutiérrez, G; Herrera-Márquez, J R; Molina-Hernández, A; Bueno-Santoyo, S; González-Ramírez, M; Hernández, J

1999-01-01

Evaluate if the rats with diabetes mellitus insulin-dependent have a minor activity of the serotonergic biosynthetic pathway through the decrease of the free fraction of L-tryptophan in plasma. Diabetes mellitus was induced in rats, and the brain serotonergic biosynthetic activity was evaluated at 7, 14, and 21 days after streptozotocin administration. The diabetic animals showed a general decrease in body weight. In plasma they had a decrease in the free fraction of L-tryptophan. Also, in the brain they show low levels of the amino acid, as well as decrease of the activity of the limiting enzyme tryptophan-5-hydroxylase and its product serotonin. Interestingly, the activity of the enzyme was higher in the brainstem from day 14, accompanied with an elevation of the neurotransmitter. The results confirm that diabetes mellitus insulin-depend induce chronic undernourishment. The low levels of L-tryptophan in blood of the diabetic animals suggest a minor transport of the amino acid to the brain and a decrease in serotonin synthesis, in cerebral cortex and hypothalamus. Besides, during the evolution of the disease, the activity of tryptophan hydroxylase was elevated, independently of L-tryptophan concentration in the brainstem of diabetic animals, suggesting a different response according to the brain region and possibly a different functional change, accompanied by an increase in the synthesis of the neurotransmitter.

Embryo yolk sac membrane kynurenine formamidase of l-tryptophan to NAD+ pathway as a primary target for organophosphorus insecticides (OPI) in OPI-induced NAD-associated avian teratogenesis.

PubMed

Seifert, Josef

2017-10-01

The objective of this study was to provide in ovo evidence for the proposed role of kynurenine formamidase of l-tryptophan to NAD + pathway in embryo yolk sac membranes as a primary target for organophosphorus insecticide (OPI) teratogens in OPI-induced NAD-associated avian teratogenesis. Slices prepared from yolk sac membranes or embryo livers of chicken eggs treated with the OPI dicrotophos and/or methyl parathion were incubated with l-tryptophan. Yolk sac membrane slices metabolized l-tryptophan in the pathway to NAD + before that function was established in livers. OPI interfered in ovo with the second step of l-tryptophan to NAD + biosynthesis by inhibiting kynurenine formamidase. Its inhibition due to the teratogen dicrotophos occurred in yolk sac membranes during the period of embryo highest susceptibility to OPI teratogens in contrast to delayed and lower inhibition caused by the nonteratogen methyl parathion. Both OPI affected liver kynurenine formamidase in a similar manner. The onsets of liver enzyme inhibition, however, were delayed by about two days and occurred at the time of the reduced embryo susceptibility to teratogens. The early disruption of l-tryptophan metabolism and higher inhibition of kynurenine formamidase in yolk sac membranes may be the factors that determine action of OPI as teratogens in chicken embryos. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of acute tryptophan depletion on mood and impulsivity in polydrug ecstasy users.

PubMed

Young, Simon N; Regoli, Martine; Leyton, Marco; Pihl, Robert O; Benkelfat, Chawki

2014-02-01

Several studies suggest users of 3,4-methylenedioxymethamphetamine (ecstasy) have low levels of serotonin. Low serotonin may make them susceptible to lowered mood. This work aims to study the acute effects on mood and impulsivity of lowering serotonin levels with acute tryptophan depletion in polydrug ecstasy users and to determine whether effects were different in men and women. In a double-blind cross-over study, participants who had used ecstasy at least 25 times (n = 13) and nonuser controls (n = 17) received a tryptophan-deficient amino acid mixture and a control amino acid mixture containing tryptophan, at least 1 week apart. Mood was measured using the profile of mood states, and impulsivity was measured with the Go/No-Go task. The main result shows that a lowering of mood after acute tryptophan depletion occurred only in female polydrug ecstasy users (n = 7), relative to controls (n = 9). Results from the Go/No-Go task suggested that impulsivity was not increased by acute tryptophan depletion in polydrug ecstasy users. The group sizes were small, when males and females were considered separately. Women polydrug ecstasy users appear to be more susceptible than men to the effects of lowered serotonin levels. If use of ecstasy alone or in conjunction with other drugs causes progressive damage of serotonin neurons, women polydrug ecstasy users may become susceptible to clinical depression.

Sex Differences in Plasma Prolactin Response to Tryptophan in Chronic Fatigue Syndrome Patients With and Without Comorbid Fibromyalgia

PubMed Central

Weaver, Shelley A.; Janal, Malvin N.; Aktan, Nadine; Ottenweller, John E.

2010-01-01

Abstract Background Some think chronic fatigue syndrome (CFS) and fibromyalgia (FM) are variants of the same illness process. This would imply that CFS patients with and without comorbid FM have similar biological underpinnings. To test this, we compared serotonergic-based responses, plasma prolactin (PRL), and self-reported measures of fatigue to intravenous infusion of tryptophan among patients with CFS alone, CFS + FM, and healthy controls. Methods Men and women with CFS alone or CFS + FM and healthy subjects, none with current major depressive disorder (MDD), were given 120 mg of l-tryptophan per kg lean body mass intravenously (i.v.). Before and after tryptophan infusion, blood samples were collected, and plasma PRL, tryptophan, and kynurenine concentrations were determined. Results Women with CFS alone, but not CFS + FM, showed upregulated plasma PRL responses compared with controls. There were no differences among groups of men. Plasma tryptophan and kynurenine concentrations did not differ among groups. Conclusions These results indicate that women with CFS alone have upregulated serotonergic tone that is not seen in those with comorbid FM. The lack of effect in men suggests a mechanism that might explain, in part, the increased prevalence of CFS in women. The data support the interpretation that CFS in women is a different illness from FM. PMID:20384451

Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase

PubMed Central

Kuehnl, Susanne; Schroecksnadel, Sebastian; Temml, Veronika; Gostner, Johanna M.; Schennach, Harald; Schuster, Daniela; Schwaiger, Stefan; Rollinger, Judith M.; Fuchs, Dietmar; Stuppner, Hermann

2013-01-01

Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells in vitro methanol and ethylacetate seed extracts were prepared from cold pressed seed cakes of C. tinctorius and three lignan derivatives, trachelogenin, arctigenin and matairesinol were isolated. The influence on tryptophan breakdown was investigated in peripheral blood mononuclear cells (PBMCs). Effects were compared to neopterin production in the same cellular assay. Both seed extracts suppressed tryptophan breakdown in stimulated PBMC. The three structurally closely related isolates exerted differing suppressive activity on PBMC: arctigenin (IC50 26.5 μM) and trachelogenin (IC50 of 57.4 μM) showed higher activity than matairesinol (IC50 >200 μM) to inhibit tryptophan breakdown. Effects on neopterin production were similar albeit generally less strong. Data show an immunosuppressive property of compounds which slows down IDO activity. The in vitro results support the view that some of the anti-inflammatory, anti-cancer and antidepressant properties of C. tinctorius lignans might relate to their suppressive influence on tryptophan breakdown. PMID:23867649

Tryptophan 334 Oxidation in Bovine Cytochrome c Oxidase Subunit I Involves Free Radical Migration

PubMed Central

Lemma-Gray, Patrizia; Weintraub, Susan T.; Carroll, Christopher A.; Musatov, Andrej; Robinson, Neal C.

2007-01-01

A single tryptophan (W334(I)) within the mitochondrial-encoded core subunits of cytochrome c oxidase (CcO) is selectively oxidized when hydrogen peroxide reacts with the binuclear center. W334(I) is converted to hydroxytryptophan as identified by HPLC-ESI/MS/MS analysis of peptides derived from the three SDS-PAGE purified subunits (total sequence coverage of subunits I, II and III was limited to 84%, 66% and 54%, respectively). W334(I) is located on the surface of CcO at the membrane interface. Two other surface tryptophans within nuclear-encoded subunits, W48(IV) and W19(VIIc), are also oxidized when hydrogen peroxide reacts with the binuclear center (Musatov et. al., 2004, Biochemistry 43, 1003–1009). Two aromatic-rich networks of amino acids were identified that link the binuclear center to the three oxidized tryptophans. We propose the following mechanism to explain these results. Electron transfer through the aromatic networks moves the free radicals generated at the binuclear center to the surface-exposed tryptophans, where they produce hydroxytryptophan. PMID:17239857

The stereospecificity and catalytic efficiency of the tryptophan synthase-catalysed exchange of the α-protons of amino acids

PubMed Central

2004-01-01

13C-NMR has been used to follow the tryptophan synthase (EC 4.2.1.20) catalysed hydrogen–deuterium exchange of the pro-2R and pro-2S protons of [2-13C]glycine at pH 7.8. 1H-NMR has also been used to follow the tryptophan-synthase-catalysed hydrogen–deuterium exchange of the α-protons of a range of L- and D-amino acids at pH 7.8. The pKa values of the α-protons of these amino acids have been estimated and we have determined whether or not their exchange rates can be predicted from their pKa values. With the exception of tryptophan and norleucine, the stereospecificities of the first-order α-proton exchange rates are independent of the size and electronegativity of the amino acid R-group. Similar results are obtained with the second-order α-proton exchange rates, except that both L-tryptophan and L-serine have much higher stereospecificities than all the other amino acids studied. PMID:15107013

RNAi-induced silencing of embryonic tryptophan oxygenase in the Pyralid moth, Plodia interpunctella

PubMed Central

Fabrick, Jeffrey A.; Kanost, Michael R.; Baker, James E.

2004-01-01

Gene silencing through the introduction of double-stranded RNA (RNA interference, RNAi) provides a powerful tool for the elucidation of gene function in many systems, including those where genomics and proteomics are incomplete. The use of RNAi technology for gene silencing in Lepidoptera has lacked significant attention compared to other systems. To demonstrate that RNAi can be utilized in the lepidopteran, Plodia interpunctella, we cloned a cDNA for tryptophan oxygenase, and showed that silencing of tryptophan oxygenase through RNAi during embryonic development resulted in loss of eye-color pigmentation. The complete amino acid sequence of Plodia tryptophan oxygenase can be accessed through NCBI Protein Database under NCBI Accession # AY427951. Abbreviation RNAi RNA interference PCR polymerase chain reaction RT-PCR reverse transcription-PCR PMID:15861231

Tryptophan

MedlinePlus

... and serotonin. Serotonin is thought to produce healthy sleep and a stable mood. In order for tryptophan in the diet to be changed into niacin, the body needs to have enough: Iron Riboflavin Vitamin B6

L-Tryptophan

MedlinePlus

... calamus, California poppy, catnip, hops, Jamaican dogwood, kava, St. John's wort, skullcap, valerian, yerba mansa, and others. ... 5-HTP, Hawaiian baby woodrose, and S-adenosylmethionine (SAMe).St. John's wortCombining L-tryptophan with St. John's wort ...

Increases in Plasma Tryptophan Are Inversely Associated with Incident Cardiovascular Disease in the Prevención con Dieta Mediterránea (PREDIMED) Study.

PubMed

Yu, Edward; Ruiz-Canela, Miguel; Guasch-Ferré, Marta; Zheng, Yan; Toledo, Estefania; Clish, Clary B; Salas-Salvadó, Jordi; Liang, Liming; Wang, Dong D; Corella, Dolores; Fitó, Montse; Gómez-Gracia, Enrique; Lapetra, José; Estruch, Ramón; Ros, Emilio; Cofán, Montserrat; Arós, Fernando; Romaguera, Dora; Serra-Majem, Lluis; Sorlí, Jose V; Hu, Frank B; Martinez-Gonzalez, Miguel A

2017-03-01

Background: During development of cardiovascular disease (CVD), interferon-γ-mediated inflammation accelerates degradation of tryptophan into downstream metabolites. A Mediterranean diet (MedDiet) consisting of a high intake of extra-virgin olive oil (EVOO), nuts, fruits, vegetables, and cereals has been demonstrated to lower the risk of CVD. The longitudinal relation between tryptophan and its downstream metabolites and CVD in the context of a MedDiet is unstudied. Objective: We sought to investigate the relation between metabolites in the tryptophan-kynurenine pathway and CVD in the context of a MedDiet pattern. Methods: We used a case-cohort design nested in the Prevención con Dieta Mediterránea randomized controlled trial. There were 231 CVD cases (stroke, myocardial infarction, cardiovascular death) among 985 participants over a median of 4.7 y of follow-up [mean ± SD age: 67.6 ± 6.1 y; 53.7% women; mean ± SD body mass index (in kg/m 2 ): 29.7 ± 3.7]. We assessed plasma tryptophan, kynurenine, kynurenic acid, 3-hydroxyanthranilic acid, and quinolinic acid concentrations at baseline and after 1 y of intervention with a MedDiet. We combined these metabolites in a kynurenine risk score (KRS) by weighting each metabolite by the adjusted coefficient of its associations with CVD. Cox models were used in the primary analysis. Results: Increases in tryptophan after 1 y were associated with a lower risk of composite CVD (HR per SD: 0.79; 95% CI: 0.63, 0.98). The baseline kynurenic acid concentration was associated with a higher risk of myocardial infarction and coronary artery disease death but not stroke. A higher KRS was more strongly associated with CVD in the control group than in the 2 intervention groups ( P -interaction = 0.003). Adjustment for changes in plasma tryptophan attenuated the inverse association between MedDiet+EVOO and CVD. Conclusions: An increase in the plasma tryptophan concentration was significantly associated with a decreased risk of CVD. A MedDiet may counteract the deleterious effects of a high kynurenine risk score. © 2017 American Society for Nutrition.

Tryptophan and tryptophan-like substances in cloud water: Occurrence and photochemical fate

NASA Astrophysics Data System (ADS)

Bianco, Angelica; Passananti, Monica; Deguillaume, Laurent; Mailhot, Gilles; Brigante, Marcello

2016-07-01

This work investigates the occurrence and photochemical behaviour of tryptophan (TRP) in the cloud aqueous phase. The concentrations of tryptophan, TRYptophan LIke Substances (TRYLIS) and HUmic LIke Substances (HULIS) in real cloud water, collected between October 2013 and November 2014 at the top of the puy de Dôme station, were determined using the Excitation-Emission-Matrix (EEM) technique. The amount of free and complexed tryptophan (TRP) up to 10-7 M in cloud aqueous phase was quantified by HPLC-UV-fluorescence analysis, and its photoreactivity under sun-simulated conditions was investigated in synthetic water samples mimicking cloud aqueous phase compositions (oceanic and continental origins). TRP undergoes direct photolysis, and its degradation is enhanced in the presence of naturally occurring species able to photo-generate hydroxyl radicals (HOrad). The polychromatic quantum yield of TRP (ϕ290-340nmTRP) is estimated to be 8.37 × 10-4 between 290 and 340 nm, corresponding to the degradation rate (RTRPd) of 1.29 × 10-11 M s-1 under our irradiation conditions. The degradation is accelerated up to 3.65 × 10-10 and 8.26 × 10-10 M s-1 in synthetic oceanic and continental cloud water samples doped with 100 μM hydrogen peroxide, respectively. Hydroxyl radical-mediated transformation leads to the generation of different functionalized and oxidized products, as well as small carboxylic acids, such as formate and acetate. Moreover, fluorescent signals of irradiated solutions indicate the formation of HULIS.

Effects of monoamine oxidase inhibition by clorgyline, deprenil or tranylcypromine on 5-hydroxytryptamine concentrations in rat brain and hyperactivity following subsequent tryptophan administration.

PubMed Central

Green, A R; Youdim, M B

1975-01-01

1 The effect of various doses of tranylcypromine on the degree of inhibition of rat brain monoamine oxidase (MAO) using 5-hydroxytryptamine (5-HT), dopamine and phenylethylamine as substrates has been examined 120 min after injection of the inhibitor. The concentration of brain 5-HT was also examined both after tranylcypromine alone and also when L-tryptophan (100 mg/kg) had been given 30 min after the tranylcypromine. 2 All doses of tranylcypromine greater than 2.5 mg/kg totally inhibited MAO oxidation of 5-HT, phenylethylamine and dopamine as measured in vitro and produced a similar rise of brain 5-HT in vivo. When tryptophan was also given, there was a further rise of brain 5-HT, which was comparable after all doses of tranylcypromine above 2.5 mg/kg and the characteristic syndrome of hyperactivity made is appearance. 3 Clorgyline (a "Type A" MAO inhibitor), in doses up to 10 mg/kg, did not totally inhibit MAO activity towards phenylethylamine although it did inhibit 5-HT oxidation by 100%. Deprenil (a "Type B" MAO inhibitor) at doses up to 10 mg/kg did not fully inhibit 5-HT oxidation although phenylethylamine oxidation was inhibited almost completely. Administration of either compound alone did not produce as great an accumulation of brain 5-HT as that seen after tranylcypromine (2.5 mg/kg) and subsequent administration of tryptophan did not cause hyperactivity or the rise of brain 5-HT seen after tranylcypromine (2.5 mg/kg) plus tryptophan. 4 Administration of clorgyline plus deprenil (2.5 mg/kg of each) almost totally inhibited oxidation of both 5-HT and phenylethylamine; subsequent tryptophan administration resulted in a rise of brain 5-HT nearly as great as that seen following tranylcypromine (2.5 mg/kg) plus tryptophan and the animals became hyperactive. 5 No evidence was found pointing to the formation of any other 5-substituted indole in the brain following tranylcypromine plus L-tryptophan administration as suggested by others. 6 It is concluded that while 5-HT may normally be metabolized in the brain by "Tye A" MAO in vivo, when this form is inhibited, 5-HT can still be metabolized by "Type B" enzyme. It is only when both forms are almost totally inhibited that the largest rise of brain 5-HT is seen and subsequent tryptophan administration produces the hyperactivity syndrome. PMID:1203627

Synthesis and stability of L-tryptophan adsorbed on Ti/MCM-41 as a catalyst for the regioselective aminolysis of styrene oxide

NASA Astrophysics Data System (ADS)

Aghapoor, Kioumars; Amini, Mostafa M.; Jadidi, Khosrow; Mohsenzadeh, Farshid; Darabi, Hossein Reza; Sayahi, Hani; Jalali, Mohammad Reza

2015-11-01

L-tryptophan is adsorbed on the titania surface of Ti/MCM-41 (L-tryp≡Ti/MCM-41) as a novel material via two steps. Ti/MCM-41 was first prepared by grafting TiCl4 on activated MCM-41 mesoporous silica in an anhydrous THF. Subsequent adsorption of L-tryptophan on the surface of grafted Ti sites from an aqueous solution afforded L-tryp≡Ti/MCM-41. Characterization of the material was carried out with thermogravimetric and differential thermogravimetric analyses, powder X-ray diffraction, BET and BJH nitrogen adsorption-desorption methods, Fourier transform infrared, UV-Visible, and energy dispersive X-ray spectroscopes. The results indicate that the adsorption of L-tryptophan on the surface of Ti/MCM-41 occurred. L-tryp≡Ti/MCM-41 was applied successfully as a heterogeneous catalyst for the ring opening of styrene oxide with aniline derivatives and demonstrated high to excellent activity and regioselectivity under microwave irradiation and solvent-free conditions. This thermal-resistant catalyst can be recycled at least five times without appreciable loss of activity, which confirms the strong adsorption of L-tryptophan on Ti/MCM-41.

Site-directed Mutagenesis Switching a Dimethylallyl Tryptophan Synthase to a Specific Tyrosine C3-Prenylating Enzyme*

PubMed Central

Fan, Aili; Zocher, Georg; Stec, Edyta; Stehle, Thilo; Li, Shu-Ming

2015-01-01

The tryptophan prenyltransferases FgaPT2 and 7-DMATS (7-dimethylallyl tryptophan synthase) from Aspergillus fumigatus catalyze C4- and C7-prenylation of the indole ring, respectively. 7-DMATS was found to accept l-tyrosine as substrate as well and converted it to an O-prenylated derivative. An acceptance of l-tyrosine by FgaPT2 was also observed in this study. Interestingly, isolation and structure elucidation revealed the identification of a C3-prenylated l-tyrosine as enzyme product. Molecular modeling and site-directed mutagenesis led to creation of a mutant FgaPT2_K174F, which showed much higher specificity toward l-tyrosine than l-tryptophan. Its catalytic efficiency toward l-tyrosine was found to be 4.9-fold in comparison with that of non-mutated FgaPT2, whereas the activity toward l-tryptophan was less than 0.4% of that of the wild-type. To the best of our knowledge, this is the first report on an enzymatic C-prenylation of l-tyrosine as free amino acid and altering the substrate preference of a prenyltransferase by mutagenesis. PMID:25477507

Association between A218C polymorphism of the tryptophan-hydroxylase-1 gene, harm avoidance and binge eating behavior in bulimia nervosa.

PubMed

Monteleone, Palmiero; Tortorella, Alfonso; Martiadis, Vassilis; Serino, Ismene; Di Filippo, Carmela; Maj, Mario

2007-06-21

Genes involved in serotonin transmission are likely involved in the biological predisposition to bulimia nervosa. We investigated whether the A218C polymorphism of the tryptophan-hydroxylase-1 gene was associated to bulimia nervosa and/or to some phenotypic aspects of the disorder. One hundred eighty Caucasian women (91 patients with bulimia nervosa and 89 healthy controls) were enrolled into the study. They underwent a blood sample collection for A218C polymorphism of the tryptophan-hydroxylase-1 genotyping and a clinical evaluation assessing comorbidity for Axis I and II psychiatric disorders, harm avoidance personality dimension and bulimic symptoms. The distribution of both tryptophan-hydroxylase-1 A218C genotypes and alleles did not significantly differ between patients and controls. Bulimic women with the AA genotype exhibited a more severe binge eating behavior and higher harm avoidance scores than those with CC genotype. These findings support the idea that tryptophan-hydroxylase-1 A218C polymorphism does not play a part in the genetic susceptibility to bulimia nervosa, but it seems to be involved in predisposing bulimic patients to a more disturbed eating behavior and higher harm avoidance.

Overexpression of EAR1 and SSH4 that encode PPxY proteins in the multivesicular body provides stability to tryptophan permease Tat2, allowing yeast cells to grow under high hydrostatic pressure

NASA Astrophysics Data System (ADS)

Hiraki, Toshiki; Usui, Keiko; Abe, Fumiyoshi

2010-12-01

Tryptophan uptake in yeast Saccharomyces cerevisiae is susceptible to high hydrostatic pressure and it limits the growth of tryptophan auxotrophic (Trp-) strains under pressures of 15-25 MPa. The susceptibility of tryptophan uptake is accounted for by the pressure-induced degradation of tryptophan permease Tat2 occurring in a Rsp5 ubiquitin ligase-dependent manner. Ear1 and Ssh4 are multivesicular body proteins that physically interact with Rsp5. We found that overexpression of either of the EAR1 or SSH4 genes enabled the Trp- cells to grow at 15-25 MPa. EAR1 and SSH4 appeared to provide stability to the Tat2 protein when overexpressed. The result suggests that Ear1 and Ssh4 negatively regulate Rsp5 on ubiquitination of Tat2. Currently, high hydrostatic pressure is widely used in bioscience and biotechnology for structurally perturbing macromolecules such as proteins and lipids or in food processing and sterilizing microbes. We suggest that hydrostatic pressure is an operative experimental parameter to screen yeast genes specifically for regulation of Tat2 through the function of Rsp5 ubiquitin ligase.

Experimental Evidence and In Silico Identification of Tryptophan Decarboxylase in Citrus Genus.

PubMed

De Masi, Luigi; Castaldo, Domenico; Pignone, Domenico; Servillo, Luigi; Facchiano, Angelo

2017-02-11

Plant tryptophan decarboxylase (TDC) converts tryptophan into tryptamine, precursor of indolealkylamine alkaloids. The recent finding of tryptamine metabolites in Citrus plants leads to hypothesize the existence of TDC activity in this genus. Here, we report for the first time that, in Citrus x limon seedlings, deuterium labeled tryptophan is decarboxylated into tryptamine, from which successively deuterated N , N , N -trimethyltryptamine is formed. These results give an evidence of the occurrence of the TDC activity and the successive methylation pathway of the tryptamine produced from the tryptophan decarboxylation. In addition, with the aim to identify the genetic basis for the presence of TDC, we carried out a sequence similarity search for TDC in the Citrus genomes using as a probe the TDC sequence reported for the plant Catharanthus roseus . We analyzed the genomes of both Citrus clementina and Citrus sinensis , available in public database, and identified putative protein sequences of aromatic l-amino acid decarboxylase. Similarly, 42 aromatic l-amino acid decarboxylase sequences from 23 plant species were extracted from public databases. Potential sequence signatures for functional TDC were then identified. With this research, we propose for the first time a putative protein sequence for TDC in the genus Citrus .

Synthesis and biological evaluation of ¹⁸F-labeled fluoropropyl tryptophan analogs as potential PET probes for tumor imaging.

PubMed

Chiotellis, Aristeidis; Mu, Linjing; Müller, Adrienne; Selivanova, Svetlana V; Keller, Claudia; Schibli, Roger; Krämer, Stefanie D; Ametamey, Simon M

2013-01-01

In the search for an efficient, fluorine-18 labeled amino acid based radiotracer for tumor imaging with positron emission tomography (PET), two new tryptophan analogs were synthesized and characterized in vitro and in vivo. Both are tryptophan alkyl-derivatives, namely 2-(3-[(18)F]fluoropropyl)-DL-tryptophan ([(18)F]2-FPTRP) and 5-(3-[(18)F]fluoro-propyl)-DL-tryptophan ([(18)F]5-FPTRP). Standard reference compounds and precursors were prepared by multi step approaches. Radiosynthesis was achieved by no-carrier-added nucleophilic [(18)F]fluorination in 29-34% decay corrected yields with radiochemical purity over 99%. In vitro cell uptake assays showed that both compounds are substrates for amino acid transport and enter small cell lung cancer cells (NCI-H69) most probably almost exclusively via large neutral amino acids transporter(s) (LAT). Small animal PET imaging with xenograft bearing mice revealed high tumor/background ratios for [(18)F]2-FPTRP comparable to the well established tyrosine analog O-(2-[(18)F]fluroethyl)-L-tyrosine ([(18)F]FET). Radiometabolite studies showed no evidence of involvement of a biotransformation step in tumor accumulation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Measurement of protein-like fluorescence in river and waste water using a handheld spectrophotometer.

PubMed

Baker, Andy; Ward, David; Lieten, Shakti H; Periera, Ryan; Simpson, Ellie C; Slater, Malcolm

2004-07-01

Protein-like fluorescence intensity in rivers increases with increasing anthropogenic DOM inputs from sewerage and farm wastes. Here, a portable luminescence spectrophotometer was used to investigate if this technology could be used to provide both field scientists with a rapid pollution monitoring tool and process control engineers with a portable waste water monitoring device, through the measurement of river and waste water tryptophan-like fluorescence from a range of rivers in NE England and from effluents from within two waste water treatment plants. The portable spectrophotometer determined that waste waters and sewerage effluents had the highest tryptophan-like fluorescence intensity, urban streams had an intermediate tryptophan-like fluorescence intensity, and the upstream river samples of good water quality the lowest tryptophan-like fluorescence intensity. Replicate samples demonstrated that fluorescence intensity is reproducible to +/- 20% for low fluorescence, 'clean' river water samples and +/- 5% for urban water and waste waters. Correlations between fluorescence measured by the portable spectrophotometer with a conventional bench machine were 0.91; (Spearman's rho, n = 143), demonstrating that the portable spectrophotometer does correlate with tryptophan-like fluorescence intensity measured using the bench spectrophotometer.

Meal composition and plasma amino acid ratios: Effect of various proteins or carbohydrates, and of various protein concentrations

NASA Technical Reports Server (NTRS)

Yokogoshi, Hidehiko; Wurtman, Richard J.

1986-01-01

The effects of meals containing various proteins and carbohydrates, and of those containing various proportions of protein (0 percent to 20 percent of a meal, by weight) or of carbohydrate (0 percent to 75 percent), on plasma levels of certain large neutral amino acids (LNAA) in rats previously fasted for 19 hours were examined. Also the plasma tryptophan ratios (the ratio of the plasma trytophan concentration to the summed concentrations of the other large neutral amino acids) and other plasma amino acid ratios were calculated. (The plasma tryptophan ratio has been shown to determine brain tryptophan levels and, thereby, to affect the synthesis and release of the neurotransmitter serotonin). A meal containing 70 percent to 75 percent of an insulin-secreting carbohydrate (dextrose or dextrin) increased plasma insulin levels and the tryptophan ratio; those containing 0 percent or 25 percent carbohydrate failed to do so. Addition of as little as 5 percent casein to a 70 percent carbohydrate meal fully blocked the increase in the plasma tryptophan ratio without affecting the secretion of insulin - probably by contributing much larger quantities of the other LNAA than of tryptophan to the blood. Dietary proteins differed in their ability to suppress the carbohydrate-induced rise in the plasma tryptophan ratio. Addition of 10 percent casein, peanut meal, or gelatin fully blocked this increase, but lactalbumin failed to do so, and egg white did so only partially. (Consumption of the 10 percent gelatin meal also produced a major reduction in the plasma tyrosine ratio, and may thereby have affected brain tyrosine levels and catecholamine synthesis.) These observations suggest that serotonin-releasing neurons in brains of fasted rats are capable of distinguishing (by their metabolic effects) between meals poor in protein but rich in carbohydrates that elicit insulin secretion, and all other meals. The changes in brain serotonin caused by carbohydrate-rich, protein-poor meals may affect subsequent food choice and various serotonin-mediated behaviors.

Correlation between breakfast tryptophan content and morning-evening in Japanese infants and students aged 0-15 yrs.

PubMed

Harada, Tetsuo; Hirotani, Masaaki; Maeda, Mari; Nomura, Hiromi; Takeuchi, Hitomi

2007-03-01

Tryptophan can be metabolized via 5-hydroxytryptamine=serotonin to melatonin by a series of 4 enzymes in pineal body. Lack of serotonin in body fluid in the brain during daytime can lead to several psychiatric disorders, while shortage of plasma-melatonin at night can be related to sleep disorders. The Morning-Evening (M-E) questionnaire and the original questionnaire including questions on sleep habits, mental symptoms, and contents of meals were administered to 1055 infants aged 0-6 yrs, 751 students attending an elementary school, and 473 students attending junior high school in Kochi City (33 degrees N). The index of tryptophan taken at breakfast (Trp-Index) was calculated as tryptophan amount per one meal based on the tryptophan included in each 100 g of the foods and a standard amount of food per one meal. A significant positive-correlation between M-E scores and Trp-Index was not shown by relatively older students, aged 9-15 yrs (Pearson's test, r=0.044-0.123, p=0.071-0.505), whereas a significant positive correlation was shown by infants and young elementary school students aged 0-8 yrs (r=0.180, 0.258, p<0.001). The more frequently the infants had difficulty falling asleep at bedtime and waking up in the morning, the less the Trp-Indices taken at breakfast were (Kruskall-Wallis-test, p=0.027 for difficulty falling asleep; p=0.008 for difficulty waking up). The more frequently infants became angry even by a little trigger, or depressed, the lower (more evening-typed) the M-E scores were (Kruskal-Wallis test: p

Comprehensive analysis of the tryptophan metabolome in urine of patients with acute intermittent porphyria.

PubMed

Gomez-Gomez, Alex; Marcos, Josep; Aguilera, Paula; To-Figueras, Jordi; Pozo, Oscar J

2017-08-15

Acute intermittent porphyria (AIP) is a rare metabolic disorder due to a deficiency of porphobilinogen deaminase, the third enzyme of the heme biosynthetic pathway. This low enzymatic activity may predispose to the appearance of acute neurological attacks. Seminal studies suggested that AIP was associated with changes in tryptophan homeostasis with inconclusive results. Therefore, the aim of this study was to analyze the urinary metabolome of AIP patients focusing on tryptophan metabolism using state-of-the-art technology. This was a case-control study including a group of 25 AIP patients with active biochemical disease and increased excretion of heme-precursors and 25 healthy controls. Tryptophan and related compounds and metabolites including: large neutral amino acids (LNAAs), serotonin, kynurenine, kynurenic acid and anthranilic acid were quantified in urine by liquid chromatography tandem-mass spectrometry (LC-MS/MS). Twenty-nine biological markers (including metabolic ratios and absolute concentrations) were compared between patients and controls. Significant differences were found in the tryptophan-kynurenine metabolic pathway. Compared to controls, AIP patients showed: (a) increased urinary excretion of kynurenine and anthranilic acid (P<0.005); (b): elevation of the kynurenine/tryptophan ratio (P<0.001) and (c): decrease of the kynurenic acid/kynurenine ratio (P=0.001). In contrast, no differences were found in the serotonin metabolic pathway independently of the markers and ratios used. The results of the study demonstrate that there is an imbalance in the kynurenine metabolic pathway in AIP patients, with an increase of the kynurenine/tryptophan ratio in urine and a reduction of the kynurenic acid/kynurenine ratio. The modified ratios suggest induction of indoleamine 2,3-deoxygenase and decreased activity of kynurenine aminotransferase in the liver. The results confirm that LC-MS/MS is useful for the characterization of the urinary metabolome of hepatic porphyrias. Copyright © 2017. Published by Elsevier B.V.

The reaction of indole with the aminoacrylate intermediate of Salmonella typhimurium tryptophan synthase: observation of a primary kinetic isotope effect with 3-[(2)H]indole.

PubMed

Cash, Michael T; Miles, Edith W; Phillips, Robert S

2004-12-15

The bacterial tryptophan synthase alpha(2)beta(2) complex catalyzes the final reactions in the biosynthesis of L-tryptophan. Indole is produced at the active site of the alpha-subunit and is transferred through a 25-30 A tunnel to the beta-active site, where it reacts with an aminoacrylate intermediate. Lane and Kirschner proposed a two-step nucleophilic addition-tautomerization mechanism for the reaction of indole with the aminoacrylate intermediate, based on the absence of an observed kinetic isotope effect (KIE) when 3-[(2)H]indole reacts with the aminoacrylate intermediate. We have now observed a KIE of 1.4-2.0 in the reaction of 3-[(2)H]indole with the aminoacrylate intermediate in the presence of monovalent cations, but not when an alpha-subunit ligand, disodium alpha-glycerophosphate (Na(2)GP), is present. Rapid-scanning stopped flow kinetic studies were performed of the reaction of indole and 3-[(2)H]indole with tryptophan synthase preincubated with L-serine, following the decay of the aminoacrylate intermediate at 350 nm, the formation of the quinonoid intermediate at 476 nm, and the formation of the L-Trp external aldimine at 423 nm. The addition of Na(2)GP dramatically slows the rate of reaction of indole with the alpha-aminoacrylate intermediate. A primary KIE is not observed in the reaction of 3-[(2)H]indole with the aminoacrylate complex of tryptophan synthase in the presence of Na(2)GP, suggesting binding of indole with tryptophan synthase is rate limiting under these conditions. The reaction of 2-methylindole does not show a KIE, either in the presence of Na(+) or Na(2)GP. These results support the previously proposed mechanism for the beta-reaction of tryptophan synthase, but suggest that the rate limiting step in quinonoid intermediate formation from indole and the aminoacrylate intermediate is deprotonation.

Preliminary randomized double-blind placebo-controlled trial of tryptophan combined with fluoxetine to treat major depressive disorder: antidepressant and hypnotic effects.

PubMed Central

Levitan, R D; Shen, J H; Jindal, R; Driver, H S; Kennedy, S H; Shapiro, C M

2000-01-01

OBJECTIVE: Because the initial phase of treatment of depression with a selective serotonin reuptake inhibitor is often complicated by a delayed onset of action of the antidepressant or severe insomnia or both, we investigated whether tryptophan, an amino acid with both antidepressant-augmenting and hypnotic effects, would benefit patients with depression at the beginning of treatment with fluoxetine. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Thirty individuals with major depressive disorder. INTERVENTIONS: Treatment over 8 weeks with 20 mg of fluoxetine per day and either tryptophan (2 to 4 g per day) or placebo. OUTCOME MEASURES: Mood was assessed using the 29-item Hamilton Depression Rating Scale (HDRS-29) and the Beck Depression Inventory (BDI). Laboratory sleep studies were done at baseline and after 4 and 8 weeks of treatment using standard procedures. RESULTS: During the first week of treatment, there was a significantly greater decrease in HDRS-29 depression scores, and a similar trend in BDI scores, in the tryptophan/fluoxetine group than in the placebo/fluoxetine group. No significant differences were noted at later time points. With respect to sleep measures, there was a significant group-by-time interaction for slow-wave sleep at week 4. Further analysis revealed a significant decrease in slow-wave sleep after 4 weeks of treatment in the placebo/fluoxetine group, but not in the tryptophan/fluoxetine group. No cases of serotonin syndrome occurred, and the combination was well tolerated, although the 4 g per day dosage of tryptophan produced daytime drowsiness. CONCLUSIONS: Combining 20 mg of fluoxetine with 2 g of tryptophan daily at the outset of treatment for major depressive disorder appears to be a safe protocol that may have both a rapid antidepressant effect and a protective effect on slow-wave sleep. Further large-scale studies are needed to confirm these initial findings. PMID:11022398

Plasma Tryptophan and the Kynurenine-Tryptophan Ratio are Associated with the Acquisition of Statural Growth Deficits and Oral Vaccine Underperformance in Populations with Environmental Enteropathy.

PubMed

Kosek, Margaret N; Mduma, Estomih; Kosek, Peter S; Lee, Gwenyth O; Svensen, Erling; Pan, William K Y; Olortegui, Maribel Paredes; Bream, Jay H; Patil, Crystal; Asayag, Cesar Ramal; Sanchez, Graciela Meza; Caulfield, Laura E; Gratz, Jean; Yori, Pablo Peñataro

2016-10-05

Early childhood enteric infections have adverse impacts on child growth and can inhibit normal mucosal responses to oral vaccines, two critical components of environmental enteropathy. To evaluate the role of indoleamine 2,3-dioxygenase 1 (IDO1) activity and its relationship with these outcomes, we measured tryptophan and the kynurenine-tryptophan ratio (KTR) in two longitudinal birth cohorts with a high prevalence of stunting. Children in rural Peru and Tanzania (N = 494) contributed 1,251 plasma samples at 3, 7, 15, and 24 months of age and monthly anthropometrics from 0 to 36 months of age. Tryptophan concentrations were directly associated with linear growth from 1 to 8 months after biomarker assessment. A 1-SD increase in tryptophan concentration was associated with a gain in length-for-age Z-score (LAZ) of 0.17 over the next 6 months in Peru (95% confidence interval [CI] = 0.11-0.23, P < 0.001) and a gain in LAZ of 0.13 Z-scores in Tanzania (95% CI = 0.03-0.22, P = 0.009). Vaccine responsiveness data were available for Peru only. An increase in kynurenine by 1 μM was associated with a 1.63 (95% CI = 1.13-2.34) increase in the odds of failure to poliovirus type 1, but there was no association with tetanus vaccine response. A KTR of 52 was 76% sensitive and 50% specific in predicting failure of response to serotype 1 of the oral polio vaccine. KTR was associated with systemic markers of inflammation, but also interleukin-10, supporting the association between IDO1 activity and immunotolerance. These results strongly suggest that the activity of IDO1 is implicated in the pathophysiology of environmental enteropathy, and demonstrates the utility of tryptophan and kynurenine as biomarkers for this syndrome, particularly in identifying those at risk for hyporesponsivity to oral vaccines. © The American Society of Tropical Medicine and Hygiene.

Plasma Tryptophan and the Kynurenine–Tryptophan Ratio Are Associated with the Acquisition of Statural Growth Deficits and Oral Vaccine Underperformance in Populations with Environmental Enteropathy

PubMed Central

Kosek, Margaret N.; Mduma, Estomih; Kosek, Peter S.; Lee, Gwenyth O.; Svensen, Erling; Pan, William K. Y.; Olortegui, Maribel Paredes; Bream, Jay H.; Patil, Crystal; Asayag, Cesar Ramal; Sanchez, Graciela Meza; Caulfield, Laura E.; Gratz, Jean; Yori, Pablo Peñataro

2016-01-01

Early childhood enteric infections have adverse impacts on child growth and can inhibit normal mucosal responses to oral vaccines, two critical components of environmental enteropathy. To evaluate the role of indoleamine 2,3-dioxygenase 1 (IDO1) activity and its relationship with these outcomes, we measured tryptophan and the kynurenine–tryptophan ratio (KTR) in two longitudinal birth cohorts with a high prevalence of stunting. Children in rural Peru and Tanzania (N = 494) contributed 1,251 plasma samples at 3, 7, 15, and 24 months of age and monthly anthropometrics from 0 to 36 months of age. Tryptophan concentrations were directly associated with linear growth from 1 to 8 months after biomarker assessment. A 1-SD increase in tryptophan concentration was associated with a gain in length-for-age Z-score (LAZ) of 0.17 over the next 6 months in Peru (95% confidence interval [CI] = 0.11–0.23, P < 0.001) and a gain in LAZ of 0.13 Z-scores in Tanzania (95% CI = 0.03–0.22, P = 0.009). Vaccine responsiveness data were available for Peru only. An increase in kynurenine by 1 μM was associated with a 1.63 (95% CI = 1.13–2.34) increase in the odds of failure to poliovirus type 1, but there was no association with tetanus vaccine response. A KTR of 52 was 76% sensitive and 50% specific in predicting failure of response to serotype 1 of the oral polio vaccine. KTR was associated with systemic markers of inflammation, but also interleukin-10, supporting the association between IDO1 activity and immunotolerance. These results strongly suggest that the activity of IDO1 is implicated in the pathophysiology of environmental enteropathy, and demonstrates the utility of tryptophan and kynurenine as biomarkers for this syndrome, particularly in identifying those at risk for hyporesponsivity to oral vaccines. PMID:27503512

FLIM-FRET image analysis of tryptophan in prostate cancer cells

NASA Astrophysics Data System (ADS)

Periasamy, Ammasi; Alam, Shagufta R.; Svindrych, Zdenek; Wallrabe, Horst

2017-07-01

A region of interest (ROI) based quantitative FLIM-FRET image analysis is developed to quantitate the autofluorescence signals of the essential amino acid tryptophan as a biomarker to investigate the metabolism in prostate cancer cells.

Two-stages of chiral selectivity in the molecular self-assembly of tryptophan

NASA Astrophysics Data System (ADS)

Guisinger, Nathan

Both chirality and molecular assembly are essential and key components to life. In this study we explore the molecular assembly of the amino acid tryptophan (both L- and D- chiralities) on Cu(111). Our investigation utilizes low temperature scanning tunneling microscopy to observe resulting assemblies at the molecular scale. We find that depositing a racemic mixture of both L- and D- tryptophan results in the assembly of basic 6 molecule ``Lego'' structures that are enantiopure. These enantiopure ``Legos'' further assemble into 1-dimensional chains one block at a time. These resulting chains are also enantiopure with chiral selectivity occurring at two stages of assembly. Utilizing scanning tunneling spectroscopy we are able to probe the electronic structure of the chiral Legos that give insight into the root of the observed selectivity. Two-stages of chiral selectivity in the molecular self-assembly of tryptophan.

Determination of Time since Death using Vitreous Humor Tryptophan.

PubMed

Ansari, Niha; Menon, Shobhana K

2017-09-01

Determination of time since death (TSD) plays very important role in forensic examination as it narrows down field of suspects and aids in deceased identification. This study utilizes the fluorescence property of vitreous humor (VH) tryptophan to determine TSD using o-phthalaldehyde (OPA). The detection limit of these fluorometric studies was found to be 8 ppb indicating sensitivity and high accuracy in TSD determination. The study was performed on selected 76 cadaver with known TSD ranging from 3 to 90 h. Excellent correlation between VH tryptophan and TSD was obtained with a coefficient of correlation R 2 = 0.9590. Results showed statistically significant increase in vitreous tryptophan with TSD up to 90 h, and the proposed method was efficaciously applied for prediction of TSD as no systematic error exist. The regression equation obtained from the study is [Trp] = 2.21 + 2.98 * TSD. © 2017 American Academy of Forensic Sciences.

Assessment of chemical exchange in tryptophan-albumin solution through (19)F multicomponent transverse relaxation dispersion analysis.

PubMed

Lin, Ping-Chang

2015-06-01

A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T2 relaxation into Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments to probe chemical exchange in a multicompartmental system. The proposed procedure was validated through analysis of (19)F T2 relaxation data of 6-fluoro-DL-tryptophan in a two-compartment solution with and without bovine serum albumin. Given the regularized NNLS analysis of a T2 relaxation curve acquired, for example, at the CPMG frequency υ CPMG  = 125, the nature of two distinct peaks in the associated T2 distribution spectrum indicated 6-fluoro-DL-tryptophan either retaining the free state, with geometric mean */multiplicative standard deviation (MSD) = 1851.2 ms */1.51, or undergoing free/albumin-bound interconversion, with geometric mean */MSD = 236.8 ms */1.54, in the two-compartment system. Quantities of the individual tryptophan species were accurately reflected by the associated T2 peak areas, with an interconversion state-to-free state ratio of 0.45 ± 0.11. Furthermore, the CPMG relaxation dispersion analysis estimated the exchange rate between the free and albumin-bound states in this fluorinated tryptophan analog and the corresponding dissociation constant of the fluorinated tryptophan-albumin complex in the chemical-exchanging, two-compartment system.

Fluorescence imaging of tryptophan and collagen cross-links to evaluate wound closure ex vivo

NASA Astrophysics Data System (ADS)

Wang, Ying; Ortega-Martinez, Antonio; Farinelli, Bill; Anderson, R. R.; Franco, Walfre

2016-02-01

Wound size is a key parameter in monitoring healing. Current methods to measure wound size are often subjective, time-consuming and marginally invasive. Recently, we developed a non-invasive, non-contact, fast and simple but robust fluorescence imaging (u-FEI) method to monitor the healing of skin wounds. This method exploits the fluorescence of native molecules to tissue as functional and structural markers. The objective of the present study is to demonstrate the feasibility of using variations in the fluorescence intensity of tryptophan and cross-links of collagen to evaluate proliferation of keratinocyte cells and quantitate size of wound during healing, respectively. Circular dermal wounds were created in ex vivo human skin and cultured in different media. Two serial fluorescence images of tryptophan and collagen cross-links were acquired every two days. Histology and immunohistology were used to validate correlation between fluorescence and epithelialization. Images of collagen cross-links show fluorescence of the exposed dermis and, hence, are a measure of wound area. Images of tryptophan show higher fluorescence intensity of proliferating keratinocytes forming new epithelium, as compared to surrounding keratinocytes not involved in epithelialization. These images are complementary since collagen cross-links report on structure while tryptophan reports on function. HE and immunohistology show that tryptophan fluorescence correlates with newly formed epidermis. We have established a fluorescence imaging method for studying epithelialization processes during wound healing in a skin organ culture model, our approach has the potential to provide a non-invasive, non-contact, quick, objective and direct method for quantitative measurements in wound healing in vivo.

Penetration of analogues of H2O and CO2 in proteins studied by room temperature phosphorescence of tryptophan.

PubMed

Wright, W W; Owen, C S; Vanderkooi, J M

1992-07-21

The influence of the protein matrix on the reactivity of external molecules with a species buried within the protein interior is considered in two general ways: (1) there may be structural fluctuations that allow for the diffusive penetration of the small molecules and/or (2) the external molecule may react over a distance. As a means to study the protein matrix, a reactive species within the protein can be formed by exciting tryptophan to the triplet state, and then the reaction of the triplet-state molecule with an external molecule can be monitored by a decrease in phosphorescence. In this work, the quenching ability (i.e., reactivity) was examined for H2S, CS2, and NO2- acting on tryptophan phosphorescence in parvalbumin, azurin, horse liver alcohol dehydrogenase, and alkaline phosphatase. A comparison of charged versus uncharged quenchers (H2S vs SH- and CS2 vs NO2-) reveals that the uncharged molecules are much more effective than charged species in quenching the phosphorescence of fully buried tryptophan, whereas the quenching for exposed tryptophan is relatively independent of the charge of the quencher. This is consistent with the view that uncharged triatomic molecules can penetrate the protein matrix to some extent. The energies of activation of the quenching reaction are low for the charged quenchers and higher for the uncharged CS2. A model is presented in which the quenchability of a buried tryptophan is inversely related to the distance from the surface when diffusion through the protein is the rate-limiting step.(ABSTRACT TRUNCATED AT 250 WORDS)

Coffee extracts suppress tryptophan breakdown in mitogen-stimulated peripheral blood mononuclear cells.

PubMed

Gostner, Johanna M; Schroecksnadel, Sebastian; Jenny, Marcel; Klein, Angela; Ueberall, Florian; Schennach, Harald; Fuchs, Dietmar

2015-01-01

Coffee consumption is considered to exert an influence on mood, the immune system, cardiovascular disease, and cancer development, but the mechanisms of action of coffee and its compounds are only partly known and understood. Immunomodulatory effects of filtered extracts of coffee and decaffeinated coffee as well as coffee compounds were investigated in human peripheral blood mononuclear cells (PBMCs) stimulated with mitogen phytohemagglutinin (PHA). The activation of PBMCs was monitored by the breakdown of tryptophan to kynurenine via enzyme indoleamine 2,3-dioxygenase (IDO) and the production of the immune activation marker neopterin by GTP-cyclohydrolase I (GCH1). Both of these biochemical pathways are induced during cellular immune activation in response to the Th1-type cytokine interferon-γ (IFN-γ). Filtered extracts of coffee and decaffeinated coffee both suppressed tryptophan breakdown and neopterin formation in mitogen-stimulated PBMCs efficiently and in a dose-dependent manner. Of 4 coffee compounds tested individually, only gallic acid and less strong also caffeic acid had a consistent suppressive influence but also affected cell viability, whereas pure caffeine and chlorogenic acid exerted no relevant effect in the PBMC assay. The parallel influence of extracts on tryptophan breakdown and neopterin production shows an anti-inflammatory and immunosuppressive property of coffee extracts and some of its compounds. When extrapolating the in vitro results to in vivo, IFN-γ-mediated breakdown of tryptophan could be counteracted by the consumption of coffee or decaffeinated coffee. This may increase tryptophan availability for the biosynthesis of the neurotransmitter 5-hydroxytryptamine (serotonin) and thereby improve mood and quality of life.

IDO inhibits a tryptophan sufficiency signal that stimulates mTOR

PubMed Central

Metz, Richard; Rust, Sonja; DuHadaway, James B.; Mautino, Mario R.; Munn, David H.; Vahanian, Nicholas N.; Link, Charles J.; Prendergast, George C.

2012-01-01

Tryptophan catabolism by indoleamine 2,3-dioxygenase (IDO) alters inflammation and favors T-cell tolerance in cancer, but the underlying molecular mechanisms remain poorly understood. The integrated stress response kinase GCN2, a sensor of uncharged tRNA that is activated by amino acid deprivation, is recognized as an important effector of the IDO pathway. However, in a mouse model of inflammatory carcinogenesis, ablation of Gcn2 did not promote resistance against tumor development like the absence of IDO does, implying the existence of additional cancer-relevant pathways that operate downstream of IDO. Addressing this gap in knowledge, we report that the IDO-mediated catabolism of tryptophan also inhibits the immunoregulatory kinases mTOR and PKC-Θ, along with the induction of autophagy. These effects were relieved specifically by tryptophan but also by the experimental agent 1-methyl-D-tryptophan (D-1MT, also known as NLG8189), the latter of which reversed the inhibitory signals generated by IDO with higher potency. Taken together, our results implicate mTOR and PKC-Θ in IDO-mediated immunosuppressive signaling, and they provide timely insights into the unique mechanism of action of D-1MT as compared with traditional biochemical inhibitors of IDO. These findings are important translationally, because they suggest broader clinical uses for D-1MT against cancers that overexpress any tryptophan catabolic enzyme (IDO, IDO2 or TDO). Moreover, they define mTOR and PKC-Θ as candidate pharmacodynamic markers for D-1MT responses in patients recruited to ongoing phase IB/II cancer trials, addressing a current clinical need. PMID:23264892

Tryptophan Depletion Promotes Habitual over Goal-Directed Control of Appetitive Responding in Humans.

PubMed

Worbe, Yulia; Savulich, George; de Wit, Sanne; Fernandez-Egea, Emilio; Robbins, Trevor W

2015-02-05

Optimal behavioral performance results from a balance between goal-directed and habitual systems of behavioral control, which are modulated by ascending monoaminergic projections. While the role of the dopaminergic system in behavioral control has been recently addressed, the extent to which changes in global serotonin neurotransmission could influence these 2 systems is still poorly understood. We employed the dietary acute tryptophan depletion procedure to reduce serotonin neurotransmission in 18 healthy volunteers and 18 matched controls. We used a 3-stage instrumental learning paradigm that includes an initial instrumental learning stage, a subsequent outcome-devaluation test, and a slip-of-action stage, which directly tests the balance between hypothetical goal-directed and habitual systems. We also employed a separate response inhibition control test to assess the behavioral specificity of the results. Acute tryptophan depletion produced a shift of behavioral performance towards habitual responding as indexed by performance on the slip-of-action test. Moreover, greater habitual responding in the acute tryptophan depletion group was predicted by a steeper decline in plasma tryptophan levels. In contrast, acute tryptophan depletion left intact the ability to use discriminative stimuli to guide instrumental choice as indexed by the instrumental learning stage and did not impair inhibitory response control. The major implication of this study is that serotonin modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. Our findings thus imply that diminished serotonin neurotransmission shifts behavioral control towards habitual responding. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Copper nanocluster-enhanced luminol chemiluminescence for high-selectivity sensing of tryptophan and phenylalanine.

PubMed

Borghei, Yasaman-Sadat; Hosseini, Morteza; Khoobi, Mehdi; Ganjali, Mohammad Reza

2017-09-01

A remarkable method for the highly sensitive detection of phenylalanine and tryptophan based on a chemiluminescence (CL) assay was reported. It was found that fluorescent copper nanoclusters capped with cysteine (Cys-CuNCs) strongly enhance the weak CL signal resulting from the reaction between luminol and H 2 O 2 . Of the amino acids tested, phenylalanine and tryptophan could enhance the above CL system sensitively. Under optimum conditions, this method was satisfactorily described by a linear calibration curve over a range of 1.0 × 10 -6 to 2.7 × 10 -5  M for phenylalanine and 1.0 × 10 -7 to 3.0 × 10 -5  M for tryptophan, respectively. The effect of various parameters such as Cys-CuNC concentration, H 2 O 2 concentration and pH on the intensity of the CL system were also studied. The main experimental advantage of the proposed method was its selectivity for two amino acids compared with others. To evaluate the applicability of the method to the analysis of a real biological sample it was used to determine tryptophan and phenylalanine in human serum and remarkable results were obtained. Copyright © 2017 John Wiley & Sons, Ltd.

Fluorescence Determination of Tryptophan Side-Chain Accessibility and Dynamics in Triple-Helical Collagen-Like Peptides

PubMed Central

Simon-Lukasik, Kristine V.; Persikov, Anton V.; Brodsky, Barbara; Ramshaw, John A. M.; Laws, William R.; Alexander Ross, J. B.; Ludescher, Richard D.

2003-01-01

We report tryptophan fluorescence measurements of emission intensity, iodide quenching, and anisotropy that describe the environment and dynamics at X and Y sites in stable collagen-like peptides of sequence (Gly-X-Y)n. About 90% of tryptophans at both sites have similar solvent exposed fluorescence properties and a lifetime of 8.5–9 ns. Analysis of anisotropy decays using an associative model indicates that these long lifetime populations undergo rapid depolarizing motion with a 0.5 ns correlation time; however, the extent of fast motion at the Y site is considerably less than the essentially unrestricted motion at the X site. About 10% of tryptophans at both sites have a shorter (∼3 ns) lifetime indicating proximity to a protein quenching group; these minor populations are immobile on the peptide surface, depolarizing only by overall trimer rotation. Iodide quenching indicates that tryptophans at the X site are more accessible to solvent. Side chains at X sites are more solvent accessible and considerably more mobile than residues at Y sites and can more readily fluctuate among alternate intermolecular interactions in collagen fibrils. This fluorescence analysis of collagen-like peptides lays a foundation for studies on the structure, dynamics, and function of collagen and of triple-helical junctions in gelatin gels. PMID:12524302

Tryptophan for the sleeping disorder and mental symptom of new-type drug dependence: A randomized, double-blind, placebo-controlled trial.

PubMed

Wang, Dongming; Li, Wenzhen; Xiao, Yang; He, Wulong; Wei, Weiquan; Yang, Longyu; Yu, Jincong; Song, Fujian; Wang, Zengzhen

2016-07-01

New-type drugs are popular with adolescents and could lead to psychiatry disorders, but no medications have been proven to be effective for these disorders of new-type drug dependence. We aimed to evaluate the efficacy of tryptophan on sleeping disorders and mental symptoms in detoxified individuals with new-type drug dependence. This randomized, placebo-controlled trial included 80 detoxified individuals with new-type drug dependence, recruited successively from a Compulsory Residential Drug Abstinence Institution in Wuhan, China, from April 2012 to November 2012. Eligible participants were randomly allocated to be treated with tryptophan (1000 mg/d, n = 40) or placebo (n = 40) for 2 weeks. The sleeping disorders and mental symptoms were assessed using Athens Insomnia Scale and Symptom Check-List-90 at baseline and 2 weeks. Results were analyzed according to the "intention-to-treat" approach. Forty-five participants completed the 2-week study, 24 in the tryptophan group and 21 in the placebo group. There were no statistically significant differences in baseline characteristics between groups and the treatment adherence was similar between groups. The reduction in the Athens Insomnia Scale score in the tryptophan group was significantly greater than that in the placebo group (P = 0.017). However, no significant differences were found in Symptom Check-List-90 scores (either by individual dimension or the overall score) between groups (all P > 0.05). The frequency of adverse events was similar and no serious adverse events were reported during the study. Tryptophan was unlikely to be effective for mental symptoms, but could alleviate sleep disorders in short term among detoxified individuals with new-type drug dependence. Future large-scale trials are required to confirm findings from this study.

Alcoholic fermentation induces melatonin synthesis in orange juice.

PubMed

Fernández-Pachón, M S; Medina, S; Herrero-Martín, G; Cerrillo, I; Berná, G; Escudero-López, B; Ferreres, F; Martín, F; García-Parrilla, M C; Gil-Izquierdo, A

2014-01-01

Melatonin (N-acetyl-5-methoxytryptamine) is a molecule implicated in multiple biological functions. Its level decreases with age, and the intake of foods rich in melatonin has been considered an exogenous source of this important agent. Orange is a natural source of melatonin. Melatonin synthesis occurs during alcoholic fermentation of grapes, malt and pomegranate. The amino acid tryptophan is the precursor of all 5-methoxytryptamines. Indeed, melatonin appears in a shorter time in wines when tryptophan is added before fermentation. The aim of the study was to measure melatonin content during alcoholic fermentation of orange juice and to evaluate the role of the precursor tryptophan. Identification and quantification of melatonin during the alcoholic fermentation of orange juice was carried out by UHPLC-QqQ-MS/MS. Melatonin significantly increased throughout fermentation from day 0 (3.15 ng/mL) until day 15 (21.80 ng/mL) reaching larger amounts with respect to other foods. Melatonin isomer was also analysed, but its content remained stable ranging from 11.59 to 14.18 ng/mL. The enhancement of melatonin occurred mainly in the soluble fraction. Tryptophan levels significantly dropped from 13.80 mg/L (day 0) up to 3.19 mg/L (day 15) during fermentation. Melatonin was inversely and significantly correlated with tryptophan (r = 0.907). Therefore, the enhancement in melatonin could be due to both the occurrence of tryptophan and the new synthesis by yeast. In summary, the enhancement of melatonin in novel fermented orange beverage would improve the health benefits of orange juice by increasing this bioactive compound. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

D-tryptophan from probiotic bacteria influences the gut microbiome and allergic airway disease.

PubMed

Kepert, Inge; Fonseca, Juliano; Müller, Constanze; Milger, Katrin; Hochwind, Kerstin; Kostric, Matea; Fedoseeva, Maria; Ohnmacht, Caspar; Dehmel, Stefan; Nathan, Petra; Bartel, Sabine; Eickelberg, Oliver; Schloter, Michael; Hartmann, Anton; Schmitt-Kopplin, Philippe; Krauss-Etschmann, Susanne

2017-05-01

Chronic immune diseases, such as asthma, are highly prevalent. Currently available pharmaceuticals improve symptoms but cannot cure the disease. This prompted demands for alternatives to pharmaceuticals, such as probiotics, for the prevention of allergic disease. However, clinical trials have produced inconsistent results. This is at least partly explained by the highly complex crosstalk among probiotic bacteria, the host's microbiota, and immune cells. The identification of a bioactive substance from probiotic bacteria could circumvent this difficulty. We sought to identify and characterize a bioactive probiotic metabolite for potential prevention of allergic airway disease. Probiotic supernatants were screened for their ability to concordantly decrease the constitutive CCL17 secretion of a human Hodgkin lymphoma cell line and prevent upregulation of costimulatory molecules of LPS-stimulated human dendritic cells. Supernatants from 13 of 37 tested probiotic strains showed immunoactivity. Bioassay-guided chromatographic fractionation of 2 supernatants according to polarity, followed by total ion chromatography and mass spectrometry, yielded C 11 H 12 N 2 O 2 as the molecular formula of a bioactive substance. Proton nuclear magnetic resonance and enantiomeric separation identified D-tryptophan. In contrast, L-tryptophan and 11 other D-amino acids were inactive. Feeding D-tryptophan to mice before experimental asthma induction increased numbers of lung and gut regulatory T cells, decreased lung T H 2 responses, and ameliorated allergic airway inflammation and hyperresponsiveness. Allergic airway inflammation reduced gut microbial diversity, which was increased by D-tryptophan. D-tryptophan is a newly identified product from probiotic bacteria. Our findings support the concept that defined bacterial products can be exploited in novel preventative strategies for chronic immune diseases. Copyright © 2016. Published by Elsevier Inc.

Mapping of sugar and amino acid availability in soil around roots with bacterial sensors of sucrose and tryptophan

PubMed

Jaeger; Lindow; Miller; Clark; Firestone

1999-06-01

We developed a technique to map the availability of sugars and amino acids along live roots in an intact soil-root matrix with native microbial soil flora and fauna present. It will allow us to study interactions between root exudates and soil microorganisms at the fine spatial scale necessary to evaluate mechanisms of nitrogen cycling in the rhizosphere. Erwinia herbicola 299R harboring a promoterless ice nucleation reporter gene, driven by either of two nutrient-responsive promoters, was used as a biosensor. Strain 299RTice exhibits tryptophan-dependent ice nucleation activity, while strain 299R(p61RYice) expresses ice nucleation activity proportional to sucrose concentration in its environment. Both biosensors exhibited up to 100-fold differences in ice nucleation activity in response to varying substrate abundance in culture. The biosensors were introduced into the rhizosphere of the annual grass Avena barbata and, as a control, into bulk soil. Neither strain exhibited significant ice nucleation activity in the bulk soil. Both tryptophan and sucrose were detected in the rhizosphere, but they showed different spatial patterns. Tryptophan was apparently most abundant in soil around roots 12 to 16 cm from the tip, while sucrose was most abundant in soil near the root tip. The largest numbers of bacteria (determined by acridine orange staining and direct microscopy) occurred near root sections with the highest apparent sucrose or tryptophan exudation. High sucrose availability at the root tip is consistent with leakage of photosynthate from immature, rapidly growing root tissues, while tryptophan loss from older root sections may result from lateral root perforation of the root epidermis.

Side-chain dynamics of a detergent-solubilized membrane protein: Measurement of tryptophan and glutamine hydrogen-exchange rates in M13 coat protein by sup 1 H NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Neil, J.D.J.; Sykes, B.D.

M13 coat protein is a small (50 amino acids) lipid-soluble protein that becomes an integral membrane protein during the infection stage of the life cycle of the M13 phage and is therefore used as a model membrane protein. To study side-chain dynamics in the protein, the authors have measured individual hydrogen-exchange rates for a primary amide in the side chain of glutamine-15 and for the indole amine of tryptophan-26. The protein was solubilized with the use of perdeuteriated sodium dodecyl sulfate (SDS), and hydrogen-exchange rates were measured by using {sup 1}H nuclear magnetic resonance spectroscopy. The glutamine-15 syn proton exchangedmore » at a rate identical with that in glutamine model peptides except that the pH corresponding to minimum exchange was elevated by about 1.5 pH units. The tryptophan-26 indole amine proton exchange was biphasic, suggesting that two populations of tryptophan-26 exist. It is suggested that the two populations may reflect protein dimerization or aggregation in the SDS micelles. The pH values of minimum exchange for tryptophan-26 in both environments were also elevated by 1.3-1.9 pH units. This phenomenon is reproduced when small tryptophan- and glutamine-containing hydrophobic peptides are dissolved in the presence of SDS micelles. The electrostatic nature of this phenomenon is proven by showing that the minimum pH for exchange can be reduced by dissolving the hydrophobic peptides in the positively charged detergent micelle dodecyltrimethylammonium bromide.« less

Characterization of a recombinant humanized anti-cocaine monoclonal antibody and its Fab fragment.

PubMed

Kirley, Terence L; Norman, Andrew B

2015-01-01

Variations of post-translational modifications are important for stability and in vivo behavior of therapeutic antibodies. A recombinant humanized anti-cocaine monoclonal antibody (h2E2) was characterized for heterogeneity of N-linked glycosylation and disulfide bonds. In addition, charge heterogeneity, which is partially due to the presence or absence of C-terminal lysine on the heavy chains, was examined. For cocaine overdose therapy, Fab fragments may be therapeutic, and thus, a simplified method of generation, purification, and characterization of the Fab fragment generated by Endoproteinase Lys-C digestion was devised. Both the intact h2E2 antibody and purified Fab fragments were analyzed for their affinities for cocaine and 2 of its metabolites, benzoylecgonine and cocaethylene, by fluorescence quenching of intrinsic antibody tyrosine and tryptophan fluorescence resulting from binding of these drugs. Binding constants obtained from fluorescence quenching measurements are in agreement with recently published radioligand and ELISA binding assays. The dissociation constants determined for the h2E2 monoclonal and its Fab fragment are approximately 1, 5, and 20 nM for cocaethylene, cocaine, and benzoylecgonine, respectively. Tryptophan fluorescence quenching (emission at 330 nm) was measured after either excitation of tyrosine and tryptophan (280 nm) or selective excitation of tryptophan alone (295 nm). More accurate binding constants are obtained using tryptophan selective excitation at 295 nm, likely due to interfering absorption of cocaine and metabolites at 280 nm. These quenching results are consistent with multiple tryptophan and tyrosine residues in or near the predicted binding location of cocaine in a previously published 3-D model of this antibody's variable region.

21 CFR 582.5915 - Tryptophane.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Tryptophane. 582.5915 Section 582.5915 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

21 CFR 582.5915 - Tryptophane.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Tryptophane. 582.5915 Section 582.5915 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

21 CFR 582.5915 - Tryptophane.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Tryptophane. 582.5915 Section 582.5915 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

21 CFR 582.5915 - Tryptophane.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Tryptophane. 582.5915 Section 582.5915 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

21 CFR 582.5915 - Tryptophane.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Tryptophane. 582.5915 Section 582.5915 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

The YPR153W gene is essential for the pressure tolerance of tryptophan permease Tat2 in the yeast Saccharomyces cerevisiae

NASA Astrophysics Data System (ADS)

Kurosaka, Goyu; Abe, Fumiyoshi

2018-01-01

In the yeast Saccharomyces cerevisiae, hydrostatic pressure at 25 MPa is known to be nonlethal but significantly impairs the uptake of tryptophan by the permease Tat2, thereby inhibiting the growth of strains that require tryptophan from the medium. Here, we found that the lack of the YPR153W gene, so far poorly characterized for its role in yeast, caused a serious adverse effect on the growth at 10-25 MPa in the strain that required tryptophan. Deletion for YPR153W resulted in an increased rate of pressure-induced degradation of Tat2, suggesting that Tat2 is destabilized in the YPR153W deletion mutant at 25 MPa. Overexpression of the TAT2 gene enabled the deletion mutant to grow at 25 MPa. These results suggest that Ypr153w is essential for the stability and proper transport function of Tat2 under pressure at 10-25 MPa.

Fluorescence quenching of human orosomucoid. Accessibility to drugs and small quenching agents.

PubMed Central

Friedman, M L; Schlueter, K T; Kirley, T L; Halsall, H B

1985-01-01

The fluorescence behaviour of human orosomucoid was investigated. The intrinsic fluorescence was more accessible to acrylamide than to the slightly larger succinimide, indicating limited accessibility to part of the tryptophan population. Although I- showed almost no quenching, that of Cs+ was enhanced, and suggested a region of negative charge proximal to an emitting tryptophan residue. Removal of more than 90% of sialic acid from the glycan chains led to no change in the Cs+, I-, succinimide or acrylamide quenching, indicating that the negatively charged region originates with the protein core. Quenching as a function of pH and temperature supported this view. The binding of chlorpromazine monitored by fluorescence quenching, in the presence and in the absence of the small quenching probes (above), led to a model of its binding domain on orosomucoid that includes two tryptophan residues relatively shielded from the bulk solvent, with the third tryptophan residue being on the periphery of the domain, or affected allotopically and near the negatively charged field. PMID:4091825

Effects of environmental lighting and tryptophan devoid diet on the rat vaginal cycle.

PubMed

Giammanco, S; Ernandes, M; La Guardia, M

1997-09-01

Cerebral serotonin level influences luteinizing hormone release and, consequently, ovulation. The present study evaluated the effects of precooked maize meal (polenta), a diet almost devoid of tryptophan the serotonin precursor on the alterations of the estrus cycle as measured by vaginal smears analysis in Wistar rats. Several conditions of environmental lighting were used in order to modify ovarian cycle: 1) natural alternating light/dark cycle; 2) continuous darkness; 3) continuous light by sodium steams: 4) continuous light by fluorescent neon tubes. Rats bred in continuous lighting showed estrus-proestrus rate significantly greater than rats bred in normal lighting or in continuous darkness. The feeding with precooked maize meal suppressed persistent estrus in rats bred in continuous lighting, and significantly cut down the estrus-proestrus frequency in any condition of environmental lighting. Our results lead to hypothesize that polenta diet, for its low tryptophan content, cutting down both tryptophan plasma content and serotonin neuronal synthesis, promotes luteinizing hormone peak.

Tryptophan derivatives regulate the transcription of Oct4 in stem-like cancer cells.

PubMed

Cheng, Jie; Li, Wenxin; Kang, Bo; Zhou, Yanwen; Song, Jiasheng; Dan, Songsong; Yang, Ying; Zhang, Xiaoqian; Li, Jingchao; Yin, Shengyong; Cao, Hongcui; Yao, Hangping; Zhu, Chenggang; Yi, Wen; Zhao, Qingwei; Xu, Xiaowei; Zheng, Min; Zheng, Shusen; Li, Lanjuan; Shen, Binghui; Wang, Ying-Jie

2015-06-10

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to environmental toxicants, is increasingly recognized as a key player in embryogenesis and tumorigenesis. Here we show that a variety of tryptophan derivatives that act as endogenous AhR ligands can affect the transcription level of the master pluripotency factor Oct4. Among them, ITE enhances the binding of the AhR to the promoter of Oct4 and suppresses its transcription. Reduction of endogenous ITE levels in cancer cells by tryptophan deprivation or hypoxia leads to Oct4 elevation, which can be reverted by administration with synthetic ITE. Consequently, synthetic ITE induces the differentiation of stem-like cancer cells and reduces their tumorigenic potential in both subcutaneous and orthotopic xenograft tumour models. Thus, our results reveal a role of tryptophan derivatives and the AhR signalling pathway in regulating cancer cell stemness and open a new therapeutic avenue to target stem-like cancer cells.

Tryptophan derivatives regulate the transcription of Oct4 in stem-like cancer cells

PubMed Central

Cheng, Jie; Li, Wenxin; Kang, Bo; Zhou, Yanwen; Song, Jiasheng; Dan, Songsong; Yang, Ying; Zhang, Xiaoqian; Li, Jingchao; Yin, Shengyong; Cao, Hongcui; Yao, Hangping; Zhu, Chenggang; Yi, Wen; Zhao, Qingwei; Xu, Xiaowei; Zheng, Min; Zheng, Shusen; Li, Lanjuan; Shen, Binghui; Wang, Ying-Jie

2015-01-01

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to environmental toxicants, is increasingly recognized as a key player in embryogenesis and tumorigenesis. Here we show that a variety of tryptophan derivatives that act as endogenous AhR ligands can affect the transcription level of the master pluripotency factor Oct4. Among them, ITE enhances the binding of the AhR to the promoter of Oct4 and suppresses its transcription. Reduction of endogenous ITE levels in cancer cells by tryptophan deprivation or hypoxia leads to Oct4 elevation, which can be reverted by administration with synthetic ITE. Consequently, synthetic ITE induces the differentiation of stem-like cancer cells and reduces their tumorigenic potential in both subcutaneous and orthotopic xenograft tumour models. Thus, our results reveal a role of tryptophan derivatives and the AhR signalling pathway in regulating cancer cell stemness and open a new therapeutic avenue to target stem-like cancer cells. PMID:26059097

Intrinsic Tryptophan Fluorescence in the Detection and Analysis of Proteins: A Focus on Förster Resonance Energy Transfer Techniques

PubMed Central

Ghisaidoobe, Amar B. T.; Chung, Sang J.

2014-01-01

Förster resonance energy transfer (FRET) occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (λEX ∼ 280 nm, λEM ∼ 350 nm), in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the protein’s) local environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic Förster resonance energy transfer (iFRET), a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins. PMID:25490136

GPR142 Controls Tryptophan-Induced Insulin and Incretin Hormone Secretion to Improve Glucose Metabolism

PubMed Central

Efanov, Alexander M.; Fang, Xiankang; Beavers, Lisa S.; Wang, Xuesong; Wang, Jingru; Gonzalez Valcarcel, Isabel C.; Ma, Tianwei

2016-01-01

GPR142, a putative amino acid receptor, is expressed in pancreatic islets and the gastrointestinal tract, but the ligand affinity and physiological role of this receptor remain obscure. In this study, we show that in addition to L-Tryptophan, GPR142 signaling is also activated by L-Phenylalanine but not by other naturally occurring amino acids. Furthermore, we show that Tryptophan and a synthetic GPR142 agonist increase insulin and incretin hormones and improve glucose disposal in mice in a GPR142-dependent manner. In contrast, Phenylalanine improves in vivo glucose disposal independently of GPR142. Noteworthy, refeeding-induced elevations in insulin and glucose-dependent insulinotropic polypeptide are blunted in Gpr142 null mice. In conclusion, these findings demonstrate GPR142 is a Tryptophan receptor critically required for insulin and incretin hormone regulation and suggest GPR142 agonists may be effective therapies that leverage amino acid sensing pathways for the treatment of type 2 diabetes. PMID:27322810

Synchrotron Ultraviolet Microspectroscopy on Rat Cortical Bone: Involvement of Tyrosine and Tryptophan in the Osteocyte and Its Environment

PubMed Central

Pallu, Stéphane; Rochefort, Gael Y.; Jaffre, Christelle; Refregiers, Matthieu; Maurel, Delphine B.; Benaitreau, Delphine; Lespessailles, Eric; Jamme, Frédéric; Chappard, Christine; Benhamou, Claude-Laurent

2012-01-01

Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately. PMID:22937127

Tryptophan as key biomarker to detect gastrointestinal tract cancer using non-negative biochemical analysis of native fluorescence and Stokes Shift spectroscopy

NASA Astrophysics Data System (ADS)

Wang, Leana; Zhou, Yan; Liu, Cheng-hui; Zhou, Lixin; He, Yong; Pu, Yang; Nguyen, Thien An; Alfano, Robert R.

2015-03-01

The objective of this study was to find out the emission spectral fingerprints for discrimination of human colorectal and gastric cancer from normal tissue in vitro by applying native fluorescence. The native fluorescence (NFL) and Stokes shift spectra of seventy-two human cancerous and normal colorectal (colon, rectum) and gastric tissues were analyzed using three selected excitation wavelengths (e.g. 300 nm, 320 nm and 340 nm). Three distinct biomarkers, tryptophan, collagen and reduced nicotinamide adenine dinucleotide hydrate (NADH), were found in the samples of cancerous and normal tissues from eighteen subjects. The spectral profiles of tryptophan exhibited a sharp peak in cancerous colon tissues under a 300 nm excitation when compared with normal tissues. The changes in compositions of tryptophan, collagen, and NADH were found between colon cancer and normal tissues under an excitation of 300 nm by the non-negative basic biochemical component analysis (BBCA) model.

Activation of the Serotonin Pathway is Associated with Poor Outcome in COPD Exacerbation: Results of a Long-Term Cohort Study.

PubMed

Meier, Marc A; Ottiger, Manuel; Vögeli, Alaadin; Steuer, Christian; Bernasconi, Luca; Thomann, Robert; Christ-Crain, Mirjam; Henzen, Christoph; Hoess, Claus; Zimmerli, Werner; Huber, Andreas; Mueller, Beat; Schuetz, Philipp

2017-06-01

Indoleamine 2,3-dioxygenase (IDO) metabolizes tryptophan to kynurenine. An increase of its activity is associated with severity in patients with pneumonia. In chronic obstructive pulmonary disease (COPD) patients, an elevation of serotonin has been reported. Experimental models showed that cigarette smoke inhibits monoamine oxidase (MAO) leading to higher levels of serotonin. We investigated the prognostic ability of tryptophan, serotonin, kynurenine, IDO, and tryptophan hydroxylase (TPH) to predict short- and long-term outcomes in patients with a COPD exacerbation. We measured tryptophan, serotonin, and kynurenine on admission plasma samples in patients with a COPD exacerbation from a previous trial by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). IDO and TPH were calculated as ratios of kynurenine over tryptophan, and serotonin over tryptophan, respectively. We studied their association with parameters measured in clinical routine at emergency department admission representing inflammation (C-reactive protein [CRP]), infection (procalcitonin [PCT]), oxygenation (SpO 2 ), as well as patients' clinical outcome, confirmed by structured phone interviews. Mortality in the 149 included patients was 53.7% within six years of follow-up. While IDO activity showed strong positive correlations, tryptophan was negatively correlated with CRP and PCT. For 30-day adverse outcome defined as death and/or intensive care unit (ICU) admission, a multivariate regression analysis adjusted for age and comorbidities found strong associations for IDO activity (adjusted odds ratios of 31.4 (95%CI 1.1-857), p = 0.041) and TPH (adjusted odds ratios 27.0 (95%CI 2.2-327), p = 0.010). TPH also showed a significant association with mortality at 18 months, (hazard ratio 2.61 (95%CI 1.2-5.8), p = 0.020). In hospitalized patients with a COPD exacerbation, higher IDO and TPH activities independently predicted adverse short-term outcomes and TPH levels were also predictive of 18-month mortality. Whether therapeutic modulation of the serotonin pathway has positive effects on outcome needs further investigation.

Etiological classification of depression based on the enzymes of tryptophan metabolism.

PubMed

Fukuda, Katsuhiko

2014-12-24

Viewed in terms of input and output, the mechanisms of depression are still akin to a black box. However, there must be main pivots for diverse types of depression. From recent therapeutic observations, both the serotonin (5-HT) and kynurenine pathways of tryptophan metabolism may be of particular importance to improved understanding of depression. Here, I propose an etiological classification of depression, based on key peripheral and central enzymes of tryptophan metabolism. Endogenous depression is caused by a larger genetic component than reactive depression. Besides enterochromaffin and mast cells, tryptophan hydroxylase 1 (TPH1), primarily expressed in the gastrointestinal tract, is also found in 5-hydroxytryptophan-producing cells (5-HTP cells) in normal intestinal enterocytes, which are thought to essentially shunt 5-HT production in 5-HT-producing cells. Genetic studies have reported an association between TPH1 and depression, or the responsiveness of depression to antidepressive medication. Therefore, it is possible that hypofunctional 5-HTP cells (reflecting TPH1 dysfunction) in the periphery lead to deficient brain 5-HT levels. Additionally,it has been reported that higher TPH2 expression in depressed suicides may reflect a homeostatic response to deficient 5-HT levels. Subsequently, endogenous depression may be caused by TPH1 dysfunction combined with compensatory TPH2 activation. Reactive depression results from life stresses and involves the hypothalamic-pituitary-adrenal axis, with resulting cortisol production inducing tryptophan 2,3-dioxygenase (TDO) activation. In secondary depression, caused by inflammation, infection, or oxidative stress, indoleamine 2,3-dioxygenase (IDO) is activated. In both reactive and secondary depression, the balance between 3-hydroxykynurenine (3-HK) and kynurenic acid may shift towards 3-HK production via kynurenine-3-monooxygenase (KMO) activation. By shifting the equilibrium position of key enzymes of tryptophan metabolism, the classical classification of depression can be reorganized, as below. Peripheral classification of depression by key enzymes: TPH1 dysfunction, TDO activation, IDO activation. Central classification: TPH2 activation, KMO activation. Etiological classification of depression expressed by peripheral (TPH1, TDO, IDO) and central (TPH2, KMO)enzymes of tryptophan metabolism may enable depression to be viewed as a clear box, with the inner components available for inspection and treatment.

Problem-Solving Test: Attenuation--A Mechanism to Regulate Bacterial Tryptophan Biosynthesis

ERIC Educational Resources Information Center

Szeberenyi, Jozsef

2010-01-01

Terms to be familiar with before you start to solve the test: tryptophan, transcription unit, operon, "trp" repressor, corepressor, operator, promoter, palindrome, initiation, elongation, and termination of transcription, open reading frame, coupled transcription/translation, chromosome-polysome complex. (Contains 2 figures and 1 footnote.)

MODE OF FISSION OF BENZENE NUCLEUS IN THE MICRO-ORGANISMS AND REGULATION OF CELL GROWTH AND DIVISION BY BENZENE DERIVATIVES.

DTIC Science & Technology

as an amino donor in this microbial system. The conversion D-tryptophan to L-tryptophan in a cell-free system can be demonstrated when an electron acceptor, such as phenazine methosulfate, is present. (Author)

Impact of HIV and Type 2 diabetes on Gut Microbiota Diversity, Tryptophan Catabolism and Endothelial Dysfunction.

PubMed

Hoel, Hedda; Hove-Skovsgaard, Malene; Hov, Johannes R; Gaardbo, Julie Christine; Holm, Kristian; Kummen, Martin; Rudi, Knut; Nwosu, Felix; Valeur, Jørgen; Gelpi, Marco; Seljeflot, Ingebjørg; Ueland, Per Magne; Gerstoft, Jan; Ullum, Henrik; Aukrust, Pål; Nielsen, Susanne Dam; Trøseid, Marius

2018-04-30

HIV infection and type 2 diabetes are associated with altered gut microbiota, chronic inflammation, and increased cardiovascular risk. We aimed to investigate the combined effect of these diseases on gut microbiota composition and related metabolites, and a potential relation to endothelial dysfunction in individuals with HIV-infection only (n = 23), diabetes only (n = 16) or both conditions (n = 21), as well as controls (n = 24). Fecal microbiota was analyzed by Illumina sequencing of the 16 S rRNA gene. Markers of endothelial dysfunction (asymmetric dimethylarginine [ADMA]), tryptophan catabolism (kynurenine/tryptophan [KT]-ratio), and inflammation (neopterin) were measured by liquid chromatography-tandem mass spectrometry. The combination of HIV and type 2 diabetes was associated with reduced gut microbiota diversity, increased plasma KT-ratio and neopterin. Microbial genes related to tryptophan metabolism correlated with KT-ratio and low alpha diversity, in particular in HIV-infected with T2D. In multivariate analyses, KT-ratio associated with ADMA (β = 4.58 [95% CI 2.53-6.63], p < 0.001), whereas microbiota composition per se was not associated with endothelial dysfunction. Our results indicate that tryptophan catabolism may be related to endothelial dysfunction, with a potentially detrimental interaction between HIV and diabetes. The potential contribution of gut microbiota and the impact for cardiovascular risk should be further explored in prospective studies powered for clinical end points.

Distinct Kynureninase and Hydroxykynureninase Activities in Microorganisms: Occurrence and Properties of a Single Physiologically Discrete Enzyme in Yeast

PubMed Central

Shetty, A. S.; Gaertner, F. H.

1973-01-01

(i) Saccharomyces cerevisiae grown in the presence of 1.0 mM l-tryptophan slowly excreted fluorescent material that was chromatographically identifiable as 3-hydroxyanthranilate but did not excrete detectable amounts of anthranilate nor rapidly deplete the medium of l-tryptophan. Under similar growth conditions, Neurospora crassa rapidly excretes anthranilate and rapidly depletes the medium of l-tryptophan. (ii) Chromatographic analysis of crude extracts from yeast revealed a single kynureninase-type enzyme whose synthesis was not measurably affected by the presence of tryptophan in the medium. Previous studies have provided evidence for two kynureninase-type enzymes in N. crassa, an inducible kynureninase and a constitutive hydroxykynureninase. (iii) Kinetic analysis of the partially purified yeast enzyme provided Michaelis constants for l-3-hydroxykynurenine and l-kynurenine of 6.7 × 10−6 and 5.4 × 10−4 M, respectively. This and other kinetic properties of the yeast enzyme are comparable to those reported for the constitutive enzyme from N. crassa. (iv) These findings suggest that S. cerevisiae has in common with N. crassa the biosynthetic enzyme hydroxykynureninase but lacks the catabolic enzyme kynureninase. Therefore, it can be predicted that, unlike N. crassa, S. cerevisiae does not carry out the tryptophan-anthranilate cycle. Distinct kynureninase-type enzymes may exist in other microorganisms and in mammals. PMID:4266242

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

NASA Astrophysics Data System (ADS)

Mounier, S.; Nicolodelli, G.; Redon, R.; Milori, D. M. B. P.

2017-04-01

The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

In-situ tryptophan-like fluorescence: A real-time indicator of faecal contamination in drinking water supplies.

PubMed

Sorensen, J P R; Lapworth, D J; Marchant, B P; Nkhuwa, D C W; Pedley, S; Stuart, M E; Bell, R A; Chirwa, M; Kabika, J; Liemisa, M; Chibesa, M

2015-09-15

Enteric pathogens are typically inferred from the presence of surrogate indicator organisms such as thermotolerant (faecal) coliforms (TTCs). The analysis of TTCs requires time-consuming incubation in suitable laboratories, which can limit sampling resolution, particularly during critical pollution events. Here, we demonstrate the use of in-situ fluorimeters targeting tryptophan-like compounds as a rapid, reagentless indicator of TTCs in groundwater-derived potable water supplies in Africa. A range of other common indicators of TTCs were also determined including nitrate, turbidity, and sanitary risk survey scores. Sampling was conducted during both the dry and wet seasons to investigate seasonality. Tryptophan-like fluorescence was the most effective predictor of both presence/absence and number of TTCs during both seasons. Seasonal changes in tryptophan-like fluorescence in deeper supplies suggest it is transported more efficiently through the aquifer than TTCs. Moreover, the perennial elevated concentrations in some wells suggest it is more resilient than TTCs in groundwater. Therefore tryptophan-like fluorescence could also be a better indicator of some smaller, more easily transported, and long-lived, pathogenic enteric viruses. These sensors have the potential to be included in real-time pollution alert systems for drinking water supplies throughout the world, as well as for mapping enteric pathogen risks in developing regions. Copyright © 2015 British Geological Survey (a component body of NERC). Published by Elsevier Ltd.. All rights reserved.

Melatonin biosynthesis in plants: multiple pathways catalyze tryptophan to melatonin in the cytoplasm or chloroplasts.

PubMed

Back, Kyoungwhan; Tan, Dun-Xian; Reiter, Russel J

2016-11-01

Melatonin is an animal hormone as well as a signaling molecule in plants. It was first identified in plants in 1995, and almost all enzymes responsible for melatonin biosynthesis had already been characterized in these species. Melatonin biosynthesis from tryptophan requires four-step reactions. However, six genes, that is, TDC, TPH, T5H, SNAT, ASMT, and COMT, have been implicated in the synthesis of melatonin in plants, suggesting the presence of multiple pathways. Two major pathways have been proposed based on the enzyme kinetics: One is the tryptophan/tryptamine/serotonin/N-acetylserotonin/melatonin pathway, which may occur under normal growth conditions; the other is the tryptophan/tryptamine/serotonin/5-methoxytryptamine/melatonin pathway, which may occur when plants produce large amounts of serotonin, for example, upon senescence. The melatonin biosynthetic capacity associated with conversion of tryptophan to serotonin is much higher than that associated with conversion of serotonin to melatonin, which yields a low level of melatonin synthesis in plants. Many melatonin intermediates are produced in various subcellular compartments, such as the cytoplasm, endoplasmic reticulum, and chloroplasts, which either facilitates or impedes the subsequent enzymatic steps. Depending on the pathways, the final subcellular sites of melatonin synthesis vary at either the cytoplasm or chloroplasts, which may differentially affect the mode of action of melatonin in plants. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Analysis of Tryptophan Residues in the Staphylococcal Multidrug Transporter QacA Reveals Long-Distance Functional Associations of Residues on Opposite Sides of the Membrane▿

PubMed Central

Hassan, Karl A.; Souhani, Talal; Skurray, Ronald A.; Brown, Melissa H.

2008-01-01

Tryptophan residues can possess a multitude of functions within a multidrug transport protein, e.g., mediating interactions with substrates or distal parts of the protein, or fulfilling a structural requirement, such as guiding the depth of membrane insertion. In this study, the nine tryptophan residues of the staphylococcal QacA multidrug efflux protein were individually mutated to alanine and phenylalanine, and the functional consequences of these changes were determined. Phenylalanine substitutions for each tryptophan residue were functionally tolerated. However, alanine modifications revealed an important functional role for three tryptophan residues, W58, W149, and W173, each of which is well conserved among QacA-related transport proteins in the major facilitator superfamily. The most functionally compromising mutation, an alanine substitution for W58, likely to be located at the extracellular interface of transmembrane segment 2, abolished all detectable QacA-mediated resistance and transport function. Second-site suppressor analyses identified several mutations that rescued the function of the W58A QacA mutant. Remarkably, all of these suppressor mutations were shown to be located in cytoplasmic loops between transmembrane helices 2 and 3 or 12 and 13, demonstrating novel functional associations between amino acid positions on opposite sides of the membrane and in distal N- and C-terminal regions of the QacA protein. PMID:18223078

Reconciling the role of serotonin in behavioral inhibition and aversion: acute tryptophan depletion abolishes punishment-induced inhibition in humans

PubMed Central

Crockett, Molly J.; Clark, Luke; Robbins, Trevor W.

2009-01-01

The neuromodulator serotonin has been implicated in a large number of affective and executive functions, but its precise contribution to motivation remains unclear. One influential hypothesis has implicated serotonin in aversive processing; another has proposed a more general role for serotonin in behavioral inhibition. Since behavioral inhibition is a pre-potent reaction to aversive outcomes, it has been a challenge to reconcile these two accounts. Here, we show that serotonin is critical for punishment-induced inhibition, but not overall motor response inhibition or reporting aversive outcomes. We used acute tryptophan depletion to temporarily lower brain serotonin in healthy human volunteers as they completed a novel task designed to obtain separate measures of motor response inhibition, punishment-induced inhibition, and sensitivity to aversive outcomes. Following a placebo treatment, participants were slower to respond under punishment conditions, compared to reward conditions. Tryptophan depletion abolished this punishment-induced inhibition, without affecting overall motor response inhibition or the ability to adjust response bias in line with punishment contingencies. The magnitude of reduction in punishment-induced inhibition depended on the degree to which tryptophan depletion reduced plasma tryptophan levels. These findings extend and clarify previous research on the role of serotonin in aversive processing and behavioral inhibition, and fit with current theorizing on serotonin's involvement in predicting aversive outcomes. PMID:19776285

Biotransformation of tryptophan by liquid medium culture of Psilocybe coprophila (Basidiomycetes).

PubMed

Alarcón, Julio; Foncea, Leyla; Aguila, Sergio; Alderete, Joel B

2006-01-01

Chemical reactions performed by fungi have been used as a modern tool in chemistry. In this work, we show the tryptophan biotransformation with Psilocybe coprophila on liquid culture medium. The results prove once more the versatility of fungi in performing a wide range of industrially attractive chemical reactions.

Enzymatic synthesis of S-phenyl-L-cysteine from keratin hydrolysis industries wastewater with tryptophan synthase.

PubMed

Xu, Lisheng; Wang, Zhiyuan; Mao, Pingting; Liu, Junzhong; Zhang, Hongjuan; Liu, Qian; Jiao, Qing-Cai

2013-04-01

An economical method for production of S-phenyl-L-cysteine from keratin acid hydrolysis wastewater (KHW) containing L-serine was developed by recombinant tryptophan synthase. This study provides us with an alternative KHW utilization strategy to synthesize S-phenyl-L-cysteine. Tryptophan synthase could efficiently convert L-serine contained in KHW to S-phenyl-L-cysteine at pH 9.0, 40°C and Trion X-100 of 0.02%. In a scale up study, L-serine conversion rate reach 97.1% with a final S-phenyl-L-cysteine concentration of 38.6 g l(-1). Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of a tryptophan supplemented diet and U.V. radiation on the rat lens.

PubMed

Mathur, R L; Sahai, P

1990-01-01

Rats maintained on a tryptophan supplemented diet and exposed to U.V. radiation showed decreased concentration of ascorbic acid in serum. In the lens, a small increase in the urea-mercaptoethanol soluble fraction was observed suggesting some oxidation of P-SH groups. The decreased concentrations of lens glutathione and ascorbic acid were accompanied with increased concentration of malondialdehyde suggesting increased oxidative stress. The activities of glutathione peroxidase decreased by about 40%. Though the activity of glutathione reductase decreased by about 58%, addition of FAD in the enzyme assay system showed restoration of lost activity. Additive effect of raised serum tryptophan concentration and ultraviolet radiation in causing damage to the eye lens is suggested.

[Aerobic methylobacteria are capable of synthesizing auxins].

PubMed

Ivanova, E G; Doronina, N V; Trotsenko, Iu A

2001-01-01

Obligately and facultatively methylotrophic bacteria with different pathways of C1 metabolism were found to be able to produce auxins, particularly indole-3-acetic acid (IAA), in amounts of 3-100 micrograms/ml. Indole-3-pyruvic acid and indole-3-acetamide were detected only in methylobacteria with the serine pathway of C1 metabolism, Methylobacterium mesophilicum and Aminobacter aminovorans. The production of auxins by methylobacteria was stimulated by the addition of tryptophan to the growth medium and was inhibited by ammonium ions. The methylobacteria under study lacked tryptophan decarboxylase and tryptophan side-chain oxidase. At the same time, they were found to contain several aminotransferases. IAA is presumably synthesized by methylobacteria through indole-3-pyruvic acid.

Does dietary tryptophan around farrowing affect sow behavior and piglet mortality

USDA-ARS?s Scientific Manuscript database

Piglet mortality remains a serious welfare and economic problem. Much of the early mortality is due to crushing by the sow. Tryptophan has been shown to reduce aggression and have a calming effect on behaviour, which may reduce the number and type of posture changes, thereby altering risk of crushin...

The structure of dimethylallyl tryptophan synthase reveals a common architecture of aromatic prenyltransferases in fungi and bacteria

PubMed Central

Metzger, Ute; Schall, Christoph; Zocher, Georg; Unsöld, Inge; Stec, Edyta; Li, Shu-Ming; Heide, Lutz; Stehle, Thilo

2009-01-01

Ergot alkaloids are toxins and important pharmaceuticals that are produced biotechnologically on an industrial scale. The first committed step of ergot alkaloid biosynthesis is catalyzed by dimethylallyl tryptophan synthase (DMATS; EC 2.5.1.34). Orthologs of DMATS are found in many fungal genomes. We report here the x-ray structure of DMATS, determined at a resolution of 1.76 Å. A complex of DMATS from Aspergillus fumigatus with its aromatic substrate L-tryptophan and with an analogue of its isoprenoid substrate dimethylallyl diphosphate reveals the structural basis of this enzyme-catalyzed Friedel-Crafts reaction, which shows strict regiospecificity for position 4 of the indole nucleus of tryptophan as well as unusual independence of the presence of Mg2+ ions. The 3D structure of DMATS belongs to a rare β/α barrel fold, called prenyltransferase barrel, that was recently discovered in a small group of bacterial enzymes with no sequence similarity to DMATS. These bacterial enzymes catalyze the prenylation of aromatic substrates in the biosynthesis of secondary metabolites (i.e., a reaction similar to that of DMATS). PMID:19706516

Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis.

PubMed

Jenkins, Trisha A; Nguyen, Jason C D; Polglaze, Kate E; Bertrand, Paul P

2016-01-20

The serotonergic system forms a diffuse network within the central nervous system and plays a significant role in the regulation of mood and cognition. Manipulation of tryptophan levels, acutely or chronically, by depletion or supplementation, is an experimental procedure for modifying peripheral and central serotonin levels. These studies have allowed us to establish the role of serotonin in higher order brain function in both preclinical and clinical situations and have precipitated the finding that low brain serotonin levels are associated with poor memory and depressed mood. The gut-brain axis is a bi-directional system between the brain and gastrointestinal tract, linking emotional and cognitive centres of the brain with peripheral functioning of the digestive tract. An influence of gut microbiota on behaviour is becoming increasingly evident, as is the extension to tryptophan and serotonin, producing a possibility that alterations in the gut may be important in the pathophysiology of human central nervous system disorders. In this review we will discuss the effect of manipulating tryptophan on mood and cognition, and discuss a possible influence of the gut-brain axis.

De-novo NAD+ synthesis regulates SIRT1-FOXO1 apoptotic pathway in response to NQO1 substrates in lung cancer cells.

PubMed

Liu, Huiying; Xing, Rong; Cheng, Xuefang; Li, Qingran; Liu, Fang; Ye, Hui; Zhao, Min; Wang, Hong; Wang, Guangji; Hao, Haiping

2016-09-20

Tryptophan metabolism is essential in diverse kinds of tumors via regulating tumor immunology. However, the direct role of tryptophan metabolism and its signaling pathway in cancer cells remain largely elusive. Here, we establish a mechanistic link from L-type amino acid transporter 1 (LAT1) mediated transport of tryptophan and the subsequent de-novo NAD+ synthesis to SIRT1-FOXO1 regulated apoptotic signaling in A549 cells in response to NQO1 activation. In response to NQO1 activation, SIRT1 is repressed leading to the increased cellular accumulation of acetylated FOXO1 that transcriptionally activates apoptotic signaling. Decreased uptake of tryptophan due to the downregulation of LAT1 coordinates with PARP-1 hyperactivation to induce rapid depletion of NAD+ pool. Particularly, the LAT1-NAD+-SIRT1 signaling is activated in tumor tissues of patients with non-small cell lung cancer. Because NQO1 activation is characterized with oxidative challenge induced DNA damage, these results suggest that LAT1 and de-novo NAD+ synthesis in NSCLC cells may play essential roles in sensing excessive oxidative stress.

Microbiome-Derived Tryptophan Metabolites and Their Aryl Hydrocarbon Receptor-Dependent Agonist and Antagonist Activities

PubMed Central

Jin, Un-Ho; Lee, Syng-Ook; Sridharan, Gautham; Lee, Kyongbum; Davidson, Laurie A.; Jayaraman, Arul; Chapkin, Robert S.; Alaniz, Robert

2014-01-01

The tryptophan metabolites indole, indole-3-acetate, and tryptamine were identified in mouse cecal extracts and fecal pellets by mass spectrometry. The aryl hydrocarbon receptor (AHR) agonist and antagonist activities of these microbiota-derived compounds were investigated in CaCo-2 intestinal cells as a model for understanding their interactions with colonic tissue, which is highly aryl hydrocarbon (Ah)–responsive. Activation of Ah-responsive genes demonstrated that tryptamine and indole 3-acetate were AHR agonists, whereas indole was an AHR antagonist that inhibited TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)–induced CYP1A1 expression. In contrast, the tryptophan metabolites exhibited minimal anti-inflammatory activities, whereas TCDD decreased phorbol ester-induced CXCR4 [chemokine (C-X-C motif) receptor 4] gene expression, and this response was AHR dependent. These results demonstrate that the tryptophan metabolites indole, tryptamine, and indole-3-acetate modulate AHR-mediated responses in CaCo-2 cells, and concentrations of indole that exhibit AHR antagonist activity (100–250 μM) are detected in the intestinal microbiome. PMID:24563545

Stability improvement of natural food colors: Impact of amino acid and peptide addition on anthocyanin stability in model beverages.

PubMed

Chung, Cheryl; Rojanasasithara, Thananunt; Mutilangi, William; McClements, David Julian

2017-03-01

Anthocyanins are prone to chemical degradation and color fading in the presence of vitamin C. The potential of three amino acids (l-phenylalanine, l-tyrosine, l-tryptophan) and a polypeptide (ε-poly-l-lysine) in prolonging the color stability of purple carrot anthocyanins (0.025%) in model beverages (0.05% l-ascorbic acid, citric acid, pH 3.0) stored at elevated temperature (40°C/7 days) was examined. In the absence of amino acids or peptides, anthocyanin degraded at first-order reaction rate. Addition of amino acids or peptide (0.1%) increased the color stability of anthocyanins, with the most significant improvement observed for l-tryptophan. The average half-life of anthocyanin color increased from 2 days to 6 days with l-tryptophan addition. Fluorescence quenching measurements revealed that the l-tryptophan interacted with anthocyanins mainly through hydrogen bonding, although some hydrophobic interaction may also have been involved. Overall, this study suggests that amino acid or peptide addition may prolong the color stability of anthocyanin in beverage products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neural and personality correlates of individual differences related to the effects of acute tryptophan depletion on future reward evaluation.

PubMed

Demoto, Yoshihiko; Okada, Go; Okamoto, Yasumasa; Kunisato, Yoshihiko; Aoyama, Shiori; Onoda, Keiichi; Munakata, Ayumi; Nomura, Michio; Tanaka, Saori C; Schweighofer, Nicolas; Doya, Kenji; Yamawaki, Shigeto

2012-01-01

In general, humans tend to discount the value of delayed reward. An increase in the rate of discounting leads to an inability to select a delayed reward over a smaller immediate reward (reward-delay impulsivity). Although deficits in the serotonergic system are implicated in this reward-delay impulsivity, there is individual variation in response to serotonin depletion. The aim of the present study was to investigate whether the effects of serotonin depletion on the ability to evaluate future reward are affected by individual personality traits or brain activation. Personality traits were assessed using the NEO-Five Factor Inventory and Temperament and Character Inventory. The central serotonergic levels of 16 healthy volunteers were manipulated by dietary tryptophan depletion. Subjects performed a delayed reward choice task that required the continuous estimation of reward value during functional magnetic resonance imaging scanning. Discounting rates were increased in 9 participants, but were unchanged or decreased in 7 participants in response to tryptophan depletion. Participants whose discounting rate was increased by tryptophan depletion had significantly higher neuroticism and lower self-directedness. Furthermore, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to the value of predicted future reward in the right insula. These results suggest that individuals who have high neuroticism and low self-directedness as personality traits are particularly vulnerable to the effect of low serotonin on future reward evaluation accompanied by altered brain activation patterns. Copyright © 2012 S. Karger AG, Basel.

Molecular docking of bacosides with tryptophan hydroxylase: a model to understand the bacosides mechanism.

PubMed

Rajathei, David Mary; Preethi, Jayakumar; Singh, Hemant K; Rajan, Koilmani Emmanuvel

2014-08-01

Tryptophan hydroxylase (TPH) catalyses l-tryptophan into 5-hydroxy-l-tryptophan, which is the first and rate-limiting step of serotonin (5-HT) biosynthesis. Earlier, we found that TPH2 up-regulated in the hippocampus of postnatal rats after the oral treatment of Bacopa monniera leaf extract containing the active compound bacosides. However, the knowledge about the interactions between bacosides with TPH is limited. In this study, we take advantage of in silico approach to understand the interaction of bacoside-TPH complex using three different docking algorithms such as HexDock, PatchDock and AutoDock. All these three algorithms showed that bacoside A and A3 well fit into the cavity consists of active sites. Further, our analysis revealed that major active compounds bacoside A3 and A interact with different residues of TPH through hydrogen bond. Interestingly, Tyr235, Thr265 and Glu317 are the key residues among them, but none of them are either at tryptophan or BH4 binding region. However, its note worthy to mention that Tyr 235 is a catalytic sensitive residue, Thr265 is present in the flexible loop region and Glu317 is known to interacts with Fe. Interactions with these residues may critically regulate TPH function and thus serotonin synthesis. Our study suggested that the interaction of bacosides (A3/A) with TPH might up-regulate its activity to elevate the biosynthesis of 5-HT, thereby enhances learning and memory formation.

Differential effects of tri-allelic 5-HTTLPR polymorphisms in healthy subjects on mood and stress performance after tryptophan challenge.

PubMed

Markus, C Rob; Firk, Christine

2009-12-01

Earlier data suggest that a polymorphism at the serotonin (5-HT) transporter gene (5-HTTLPR) may affect depression particularly in the face of stress due to interactions between 5-HT vulnerability and stress exposure. However, this interaction between 5-HT transporter-linked transcriptional promoter region (5-HTTLPR), 5-HT vulnerability and the affective effects of stress exposure has not yet been investigated. As participants with short-allele 5-HTTLPR genotypes may exhibit enhanced 5-HT vulnerability, this study examines the effects of tryptophan challenge on stress reactivity and performance in healthy participants with S'/S' vs L'/L' genotypes. Sixteen healthy subjects with homozygotic short alleles (S'/S'=S/L(G,) L(G)/L(G)) and 14 subjects with homozygotic long alleles (L'/L'=L(A)/L(A)) of the 5-HTTLPR were tested in a double-blind placebo-controlled design under acute stress exposure following tryptophan challenge or placebo. Although there were no 5-HTTLPR-related differences in stress responses, significant beneficial effects of tryptophan challenge on mood and stress performance were exclusively found in participants with S'/S' genotypes. These findings suggest greater brain 5-HT vulnerability to tryptophan manipulations in participants with S'/S' as compared with L'/L' 5-HTTLPR genotypes. This apparent genetic 5-HT vulnerability may become a meaningful risk factor for depression when brain 5-HT falls below functional need in the face of real severe stressful life events.

Strategy for pH control and pH feedback-controlled substrate feeding for high-level production of L-tryptophan by Escherichia coli.

PubMed

Cheng, Li-Kun; Wang, Jian; Xu, Qing-Yang; Zhao, Chun-Guang; Shen, Zhi-Qiang; Xie, Xi-Xian; Chen, Ning

2013-05-01

Optimum production of L-tryptophan by Escherichia coli depends on pH. Here, we established conditions for optimizing the production of L-tryptophan. The optimum pH range was 6.5-7.2, and pH was controlled using a three-stage strategy [pH 6.5 (0-12 h), pH 6.8 (12-24 h), and pH 7.2 (24-38 h)]. Specifically, ammonium hydroxide was used to adjust pH during the initial 24 h, and potassium hydroxide and ammonium hydroxide (1:2, v/v) were used to adjust pH during 24-38 h. Under these conditions, NH4 (+) and K(+) concentrations were kept below the threshold for inhibiting L-tryptophan production. Optimization was also accomplished using ratios (v/v) of glucose to alkali solutions equal to 4:1 (5-24 h) and 6:1 (24-38 h). The concentration of glucose and the pH were controlled by adjusting the pH automatically. Applying a pH-feedback feeding method, the steady-state concentration of glucose was maintained at approximately 0.2 ± 0.02 g/l, and acetic acid accumulated to a concentration of 1.15 ± 0.03 g/l, and the plasmid stability was 98 ± 0.5 %. The final, optimized concentration of L-tryptophan was 43.65 ± 0.29 g/l from 52.43 ± 0.38 g/l dry cell weight.

[Environment of tryptophan residues in proteins--a factor for stability to oxidative nitrosylation. I. Analysis of primary structure].

PubMed

Beda, N V; Nedospasov, A A

2001-01-01

Micellar catalysis under aerobic conditions effectively accelerates oxidative nitrosylation because of solubilization of NO and O2 by protein membranes and hydrophobic nuclei. Nitrosylating intermediates NOx (NO2, N2O3, N2O4) form mainly in the hydrophobic phase, and therefore their solubility in aqueous phase is low and hydrolysis is rapid, local concentration of NOx in the hydrophobic phase being essentially higher than in aqueous. Tryptophan is a hydrophobic residue and can nitrosylate with the formation of isomer N-nitrosotryptophans (NOW). Without denitrosylation mechanism, the accumulation of NOW in proteins of NO-synthesizing organisms would be constant, and long-living proteins would contain essential amounts of NOW, which is however not the case. Using Protein Data Bank (more than 78,000 sequences) we investigated the distribution of tryptophan residues environment (22 residues on each side of polypeptide chain) in proteins with known primary structure. Charged and polar residues (D, H, K, N, Q, R, S) are more incident in the immediate surrounding of tryptophan (-6, -5, -2, -1, 1, 2, 4) and hydrophobic residues (A, F, I, L, V, Y) are more rare than in remote positions. Hence, an essential part of tryptophan residues is situated in hydrophilic environment, which decreases the nitrosylation velocity because of lower NOx concentration in aqueous phase and allows the denitrosylation reactions course via nitrosonium ion transfer on nucleophils of functional groups of protein and low-molecular compounds in aqueous phase.

Enantioseparation of Racemic Flurbiprofen by Aqueous Two-Phase Extraction With Binary Chiral Selectors of L-dioctyl Tartrate and L-tryptophan.

PubMed

Chen, Zhi; Zhang, Wei; Wang, Liping; Fan, Huajun; Wan, Qiang; Wu, Xuehao; Tang, Xunyou; Tang, James Z

2015-09-01

A novel method for chiral separation of flurbiprofen enantiomers was developed using aqueous two-phase extraction (ATPE) coupled with biphasic recognition chiral extraction (BRCE). An aqueous two-phase system (ATPS) was used as an extracting solvent which was composed of ethanol (35.0% w/w) and ammonium sulfate (18.0% w/w). The chiral selectors in ATPS for BRCE consideration were L-dioctyl tartrate and L-tryptophan, which were screened from amino acids, β-cyclodextrin derivatives, and L-tartrate esters. Factors such as the amounts of L-dioctyl tartrate and L-tryptophan, pH, flurbiprofen concentration, and the operation temperature were investigated in terms of chiral separation of flurbiprofen enantiomers. The optimum conditions were as follows: L-dioctyl tartrate, 80 mg; L-tryptophan, 40 mg; pH, 4.0; flurbiprofen concentration, 0.10 mmol/L; and temperature, 25 °C. The maximum separation factor α for flurbiprofen enantiomers could reach 2.34. The mechanism of chiral separation of flurbiprofen enantiomers is discussed and studied. The results showed that synergistic extraction has been established by L-dioctyl tartrate and L-tryptophan, which enantioselectively recognized R- and S-enantiomers in top and bottom phases, respectively. Compared to conventional liquid-liquid extraction, ATPE coupled with BRCE possessed higher separation efficiency and enantioselectivity without the use of any other organic solvents. The proposed method is a potential and powerful alternative to conventional extraction for separation of various enantiomers. © 2015 Wiley Periodicals, Inc.

Gastric pentadecapeptide BPC 157 effective against serotonin syndrome in rats.

PubMed

Boban Blagaic, Alenka; Blagaic, Vladimir; Mirt, Mirela; Jelovac, Nikola; Dodig, Goran; Rucman, Rudolf; Petek, Marijan; Turkovic, Branko; Anic, Tomislav; Dubovecak, Miroslav; Staresinic, Mario; Seiwerth, Sven; Sikiric, Predrag

2005-04-11

Serotonin syndrome commonly follows irreversible monoamine oxidase (MAO)-inhibition and subsequent serotonin (5-HT) substrate (in rats with fore paw treading, hind limbs abduction, wet dog shake, hypothermia followed by hyperthermia). A stable gastric pentadecapeptide BPC 157 with very safe profile (inflammatory bowel disease clinical phase II, PL-10, PLD-116, PL-14736, Pliva) reduced the duration of immobility to a greater extent than imipramine, and, given peripherally, has region specific influence on brain 5-HT synthesis (alpha-[14C]methyl-L-tryptophan autoradiographic measurements) in rats, different from any other serotonergic drug. Thereby, we investigate this peptide (10 microg, 10 ng, 10 pg/kg i.p.) in (i) full serotonin syndrome in rat combining pargyline (irreversible MAO-inhibition; 75 mg/kg i.p.) and subsequent L-tryptophan (5-HT precursor; 100 mg/kg i.p.; BPC 157 as a co-treatment), or (ii, iii) using pargyline or L-tryptophan given separately, as a serotonin-substrate with (ii) pargyline (BPC 157 as a 15-min posttreatment) or as a potential serotonin syndrome inductor with (iii) L-tryptophan (BPC 157 as a 15 min-pretreatment). In all experiments, gastric pentadecapeptide BPC 157 contrasts with serotonin-syndrome either (i) presentation (i.e., particularly counteracted) or (ii) initiation (i.e., neither a serotonin substrate (counteraction of pargyline), nor an inductor for serotonin syndrome (no influence on L-tryptophan challenge)). Indicatively, severe serotonin syndrome in pargyline + L-tryptophan rats is considerably inhibited even by lower pentadecapeptide BPC 157 doses regimens (particularly disturbances such as hyperthermia and wet dog shake thought to be related to stimulation of 5-HT2A receptors), while the highest pentadecapeptide dose counteracts mild disturbances present in pargyline rats (mild hypothermia, feeble hind limbs abduction). Thereby, in severe serotonin syndrome, gastric pentadecapeptide BPC 157 (alone, no behavioral or temperature effect) has a beneficial activity, which is likely, particular, and mostly related to a rather specific counteraction of 5-HT2A receptors phenomena.

Tryptophan decarboxylase plays an important role in ajmalicine biosynthesis in Rauvolfia verticillata.

PubMed

Liu, Wanhong; Chen, Rong; Chen, Min; Zhang, Haoxing; Peng, Meifang; Yang, Chunxian; Ming, Xingjia; Lan, Xiaozhong; Liao, Zhihua

2012-07-01

Tryptophan decarboxylase (TDC) converts tryptophan into tryptamine that is the indole moiety of ajmalicine. The full-length cDNA of Rauvolfia verticillata (RvTDC) was 1,772 bps that contained a 1,500-bp ORF encoding a 499-amino-acid polypeptide. Recombinant 55.5 kDa RvTDC converted tryptophan into tryptamine. The K (m) of RvTDC for tryptophan was 2.89 mM, higher than those reported in other TIAs-producing plants. It demonstrated that RvTDC had lower affinity to tryptophan than other plant TDCs. The K (m) of RvTDC was also much higher than that of strictosidine synthase and strictosidine glucosidase in Rauvolfia. This suggested that TDC might be the committed-step enzyme involved in ajmalicine biosynthesis in R. verticillata. The expression of RvTDC was slightly upregulated by MeJA; the five MEP pathway genes and SGD showed no positive response to MeJA; and STR was sharply downregulated by MeJA. MeJA-treated hairy roots produced higher level of ajmalicine (0.270 mg g(-1) DW) than the EtOH control (0.183 mg g(-1) DW). Highest RvTDC expression level was detected in hairy root, about respectively 11, 19, 65, and 109-fold higher than in bark, young leaf, old leaf, and root. Highest ajmalicine content was also found in hairy root (0.249 mg g(-1) DW) followed by in bark (0.161 mg g(-1) DW) and young leaf (0.130 mg g(-1) DW), and least in root (0.014 mg g(-1) DW). Generally, the expression level of RvTDC was positively consistent with the accumulation of ajmalicine. Therefore, it could be deduced that TDC might be the key enzyme involved in ajmalicine biosynthesis in Rauvolfia.

Phosphoenolpyruvate:glucose phosphotransferase system modification increases the conversion rate during L-tryptophan production in Escherichia coli.

PubMed

Liu, Lina; Chen, Sheng; Wu, Jing

2017-10-01

Escherichia coli FB-04(pta1), a recombinant L-tryptophan production strain, was constructed in our laboratory. However, the conversion rate (L-tryptophan yield per glucose) of this strain is somewhat low. In this study, additional genes have been deleted in an effort to increase the conversion rate of E. coli FB-04(pta1). Initially, the pykF gene, which encodes pyruvate kinase I (PYKI), was inactivated to increase the accumulation of phosphoenolpyruvate, a key L-tryptophan precursor. The resulting strain, E. coli FB-04(pta1)ΔpykF, showed a slightly higher L-tryptophan yield and a higher conversion rate in fermentation processes. To further improve the conversion rate, the phosphoenolpyruvate:glucose phosphotransferase system (PTS) was disrupted by deleting the ptsH gene, which encodes the phosphocarrier protein (HPr). The levels of biomass, L-tryptophan yield, and conversion rate of this strain, E. coli FB-04(pta1)ΔpykF/ptsH, were especially low during fed-batch fermentation process, even though it achieved a significant increase in conversion rate during shake-flask fermentation. To resolve this issue, four HPr mutations (N12S, N12A, S46A, and S46N) were introduced into the genomic background of E. coli FB-04(pta1)ΔpykF/ptsH, respectively. Among them, the strain harboring the N12S mutation (E. coli FB-04(pta1)ΔpykF-ptsHN12S) showed a prominently increased conversion rate of 0.178 g g -1 during fed-batch fermentation; an increase of 38.0% compared with parent strain E. coli FB-04(pta1). Thus, mutation of the genomic of ptsH gene provided an alternative method to weaken the PTS and improve the efficiency of carbon source utilization.

Aggression in Replacement Grower and Finisher Gilts fed a High-Tryptophan Diet and the Effect of Long-term Human-Animal Interaction

USDA-ARS?s Scientific Manuscript database

Aggression is a major problem for swine production as it negatively impacts the pigs’ health and welfare. Dietary approaches such as increasing tryptophan (TRP) ingestion to raise cerebral serotonin (5-HT) – a key neurotransmitter for aggression control, and long-term positive social handling have b...

Prolonged triboluminescence in clays and other minerals

NASA Technical Reports Server (NTRS)

Lahav, N.; Coyne, L. M.; Lawless, J. G.

1982-01-01

The decay curves of various triboluminescent-excited materials were obtained, including well-crystallized and poorly crystallized kaolin, bentonite, quartz, sodium chloride, and chalk calcite. A qualitative increase in triboluminescence was observed for kaolin dipped in water or tryptophan solution compared to dry kaolin, and for frozen kaolin and montmorillonite pastes. Theoretical explanations for the tryptophan effect are discussed.

Metabolic pathway interruption: CRISPR/Cas9-mediated knockout of tryptophan 2,3-oxygenase in Tribolium castaneum

USDA-ARS?s Scientific Manuscript database

The Tribolium castaneum vermilion gene encodes tryptophan 2,3-dioxygenase, a pivotal enzyme in the ommochrome pathway that is responsible for the black eye color. T. castaneum strains with a loss-of-function mutation, vermilion white (vw), lack both the promoter and the first 80% of the vermilion co...

Association between Tryptophan Hydroxylase 2 Gene Polymorphism and Completed Suicide

ERIC Educational Resources Information Center

Fudalej, Sylwia; Ilgen, Mark; Fudalej, Marcin; Kostrzewa, Grazyna; Barry, Kristen; Wojnar, Marcin; Krajewski, Pawel; Blow, Frederic; Ploski, Rafal

2010-01-01

The association between suicide and a single nucleotide polymorphism (rs1386483) was examined in the recently identified tryptophan hydroxylase 2 (TPH2) gene. Blood samples of 143 suicide victims and 162 age- and sex-matched controls were examined. The frequency of the TT genotype in the TPH2 polymorphism was higher in suicide victims than in…

Quenching of Tryptophan Fluorescence in Unfolded Cytochrome "c": A Biophysics Experiment for Physical Chemistry Students

ERIC Educational Resources Information Center

Schlamadinger, Diana E.; Kats, Dina I.; Kim, Judy E.

2010-01-01

Laboratory experiments that focus on protein folding provide excellent opportunities for undergraduate students to learn important topics in the expanding interdisciplinary field of biophysics. Here, we describe the use of Stern-Volmer plots to determine the extent of solvent accessibility of the single tryptophan residue (trp-59) in unfolded and…

Formation of tryptophan radicals in irradiated aqueous solutions of hexachloroplatinate(IV): a flash photolysis study.

PubMed

Zang, L; Rodgers, M A

1999-10-01

The oxidation of tryptophan photosensitized by PtCl6(2-) has been investigated in aqueous solutions at different pH using nanosecond laser flash photolysis. Cationic and neutral radicals of tryptophan were detected at pH 2.8 and 8.5, respectively. The generation of the radical was attributed to oxidation by Cl2- that was formed from the homolytic bond cleavage in the excited state of PtCl6(2-). The bimolecular rate constant derived from the kinetics analysis, 2.8 +/- 0.2 x 10(9) M-1 s-1, is in good agreement with the value obtained in earlier pulse radiolysis studies. Both the cationic and neutral radicals decayed by second-order kinetics, consistent with the dimerization process.

The preference of tryptophan for membrane interfaces: insights from N-methylation of tryptophans in gramicidin channels.

PubMed

Sun, Haiyan; Greathouse, Denise V; Andersen, Olaf S; Koeppe, Roger E

2008-08-08

To better understand the structural and functional roles of tryptophan at the membrane/water interface in membrane proteins, we examined the structural and functional consequences of Trp --> 1-methyl-tryptophan substitutions in membrane-spanning gramicidin A channels. Gramicidin A channels are miniproteins that are anchored to the interface by four Trps near the C terminus of each subunit in a membrane-spanning dimer. We masked the hydrogen bonding ability of individual or multiple Trps by 1-methylation of the indole ring and examined the structural and functional changes using circular dichroism spectroscopy, size exclusion chromatography, solid state (2)H NMR spectroscopy, and single channel analysis. N-Methylation causes distinct changes in the subunit conformational preference, channel-forming propensity, single channel conductance and lifetime, and average indole ring orientations within the membrane-spanning channels. The extent of the local ring dynamic wobble does not increase, and may decrease slightly, when the indole NH is replaced by the non-hydrogen-bonding and more bulky and hydrophobic N-CH(3) group. The changes in conformational preference, which are associated with a shift in the distribution of the aromatic residues across the bilayer, are similar to those observed previously with Trp --> Phe substitutions. We conclude that indole N-H hydrogen bonding is of major importance for the folding of gramicidin channels. The changes in ion permeability, however, are quite different for Trp --> Phe and Trp --> 1-methyl-tryptophan substitutions, indicating that the indole dipole moment and perhaps also ring size and are important for ion permeation through these channels.

Function of the tryptophan metabolite, L-kynurenine, in human corneal endothelial cells

PubMed Central

Lahdou, Imad; Scheuerle, Alexander; Höftberger, Romana; Aboul-Enein, Fahmy

2009-01-01

Purpose Penetrating keratoplasty has been the mainstay for the treatment of blindness and is the most common form of tissue transplantation worldwide. Due to significant rates of rejection, treatment of immunological transplant reactions is of wide interest. Recently in a mouse model, the overexpression of indoeleamine 2,3 dioxigenase (IDO) was led to an extension in corneal allograft survival. L-kynurenine is a tryptophan metabolite, which may render activated T-cells apoptotic and therefore might modulate an allogenous transplant reaction. The function of L-kynurenine in the human cornea remains unclear. We analyzed the expression levels of IDO in human corneal endothelial cells (HCECs) and downstream tryptophan/kynurenine mechanisms in cell culture. Methods An immunological activation profile was determined in proliferation assays of monocytes from healthy donors. Reversed-phase high pressure liquid chromatography (HPLC), western blot, real time polymerase chain reaction (PCR), and microarray analyses were used. The expression of IDO and immunological infiltration of rejected human corneal allografts (n=12) were analyzed by immunohistochemistry. Results We found IDO and an associated tryptophan/kynurenine transporter protein exchange mechanism upregulated by inflammatory cytokines in HCECs. The inhibition of T-cell proliferation might depend on rapid delivery of the tryptophan metabolite, L-kynurenine, to the local corneal environment. Microarray analysis gives evidence that the large amino acid transporter 1 (LAT1) transporter protein is responsible for this mechanism. Conclusions Our data support that adequate levels of functional L-kynurenine might contribute to the maintenance of a relative immune privilege in the ocular anterior chamber, thereby contributing to the preservation of corneal allogeneic cells. PMID:19597571

Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis

PubMed Central

Jenkins, Trisha A.; Nguyen, Jason C. D.; Polglaze, Kate E.; Bertrand, Paul P.

2016-01-01

The serotonergic system forms a diffuse network within the central nervous system and plays a significant role in the regulation of mood and cognition. Manipulation of tryptophan levels, acutely or chronically, by depletion or supplementation, is an experimental procedure for modifying peripheral and central serotonin levels. These studies have allowed us to establish the role of serotonin in higher order brain function in both preclinical and clinical situations and have precipitated the finding that low brain serotonin levels are associated with poor memory and depressed mood. The gut-brain axis is a bi-directional system between the brain and gastrointestinal tract, linking emotional and cognitive centres of the brain with peripheral functioning of the digestive tract. An influence of gut microbiota on behaviour is becoming increasingly evident, as is the extension to tryptophan and serotonin, producing a possibility that alterations in the gut may be important in the pathophysiology of human central nervous system disorders. In this review we will discuss the effect of manipulating tryptophan on mood and cognition, and discuss a possible influence of the gut-brain axis. PMID:26805875

High-Fat Diet and Voluntary Chronic Aerobic Exercise Recover Altered Levels of Aging-Related Tryptophan Metabolites along the Kynurenine Pathway

PubMed Central

Lee, Keon-Joo; Cho, Joo-Youn; Lee, Soon-Tae; Kim, Hwa Suk; Shim, Jun Hwa; Lee, Sang Kun; Kim, Manho

2017-01-01

Tryptophan metabolites regulate a variety of physiological processes, and their downstream metabolites enter the kynurenine pathway. Age-related changes of metabolites and activities of associated enzymes in this pathway are suggestable and would be potential intervention targets. Blood levels of serum tryptophan metabolites in C57BL/6 mice of different ages, ranging from 6 weeks to 10 months, were assessed using high-performance liquid chromatography, and the enzyme activities for each metabolic step were estimated using the ratio of appropriate metabolite levels. Mice were subjected to voluntary chronic aerobic exercise or high-fat diet to assess their ability to rescue age-related alterations in the kynurenine pathway. The ratio of serum kynurenic acid (KYNA) to 3-hydroxylkynurenine (3-HK) decreased with advancing age. Voluntary chronic aerobic exercise and high-fat diet rescued the decreased KYNA/3-HK ratio in the 6-month-old and 8-month-old mice groups. Tryptophan metabolites and their associated enzyme activities were significantly altered during aging, and the KYNA/3-HK ratio was a meaningful indicator of aging. Exercise and high-fat diet could potentially recover the reduction of the KYNA/3-HK ratio in the elderly. PMID:28680298

De-novo NAD+ synthesis regulates SIRT1-FOXO1 apoptotic pathway in response to NQO1 substrates in lung cancer cells

PubMed Central

Cheng, Xuefang; Li, Qingran; Liu, Fang; Ye, Hui; Zhao, Min; Wang, Hong; Wang, Guangji; Hao, Haiping

2016-01-01

Tryptophan metabolism is essential in diverse kinds of tumors via regulating tumor immunology. However, the direct role of tryptophan metabolism and its signaling pathway in cancer cells remain largely elusive. Here, we establish a mechanistic link from L-type amino acid transporter 1 (LAT1) mediated transport of tryptophan and the subsequent de-novo NAD+ synthesis to SIRT1-FOXO1 regulated apoptotic signaling in A549 cells in response to NQO1 activation. In response to NQO1 activation, SIRT1 is repressed leading to the increased cellular accumulation of acetylated FOXO1 that transcriptionally activates apoptotic signaling. Decreased uptake of tryptophan due to the downregulation of LAT1 coordinates with PARP-1 hyperactivation to induce rapid depletion of NAD+ pool. Particularly, the LAT1-NAD+-SIRT1 signaling is activated in tumor tissues of patients with non-small cell lung cancer. Because NQO1 activation is characterized with oxidative challenge induced DNA damage, these results suggest that LAT1 and de-novo NAD+ synthesis in NSCLC cells may play essential roles in sensing excessive oxidative stress. PMID:27566573

Application of Tryptophan Fluorescence Bandwidth-Maximum Plot in Analysis of Monoclonal Antibody Structure.

PubMed

Huang, Cheng-Yen; Hsieh, Ming-Ching; Zhou, Qinwei

2017-04-01

Monoclonal antibodies have become the fastest growing protein therapeutics in recent years. The stability and heterogeneity pertaining to its physical and chemical structures remain a big challenge. Tryptophan fluorescence has been proven to be a versatile tool to monitor protein tertiary structure. By modeling the tryptophan fluorescence emission envelope with log-normal distribution curves, the quantitative measure can be exercised for the routine characterization of monoclonal antibody overall tertiary structure. Furthermore, the log-normal deconvolution results can be presented as a two-dimensional plot with tryptophan emission bandwidth vs. emission maximum to enhance the resolution when comparing samples or as a function of applied perturbations. We demonstrate this by studying four different monoclonal antibodies, which show the distinction on emission bandwidth-maximum plot despite their similarity in overall amino acid sequences and tertiary structures. This strategy is also used to demonstrate the tertiary structure comparability between different lots manufactured for one of the monoclonal antibodies (mAb2). In addition, in the unfolding transition studies of mAb2 as a function of guanidine hydrochloride concentration, the evolution of the tertiary structure can be clearly traced in the emission bandwidth-maximum plot.

Interaction of the alpha-toxin of Staphylococcus aureus with the liposome membrane.

PubMed

Ikigai, H; Nakae, T

1987-02-15

When the liposome membrane is exposed to the alpha-toxin of Staphylococcus aureus, fluorescence of the tryptophan residue(s) of the toxin molecule increases concomitantly with the degree of toxin-hexamer formation (Ikigai, H., and Nakae, T. (1985) Biochem. Biophys. Res. Commun. 130, 175-181). In the present study, the toxin-membrane interaction was distinguished from the hexamer formation by the fluorescence energy transfer from the tryptophan residue(s) of the toxin molecule to the dansylated phosphatidylethanolamine in phosphatidylcholine liposome. Measurement of these two parameters yielded the following results. The effect of the toxin concentration and phospholipid concentration on these two parameters showed first order kinetics. The effect of liposome size on the energy transfer and the fluorescence increment of the tryptophan residue(s) was only detectable in small liposomes. Under moderately acidic or basic conditions, the fluorescence energy transfer always preceded the fluorescence increment of the tryptophan residue(s). The fluorescence increment at 336 nm at temperatures below 20 degrees C showed a latent period, whereas the fluorescence energy transfer did not. These results were thought to indicate that when alpha-toxin damages the target membrane, the molecule interacts with the membrane first, and then undergoes oligomerization within the membrane.

Volatile anesthetics affect nutrient availability in yeast.

PubMed Central

Palmer, Laura K; Wolfe, Darren; Keeley, Jessica L; Keil, Ralph L

2002-01-01

Volatile anesthetics affect all cells and tissues tested, but their mechanisms and sites of action remain unknown. To gain insight into the cellular activities of anesthetics, we have isolated genes that, when overexpressed, render Saccharomyces cerevisiae resistant to the volatile anesthetic isoflurane. One of these genes, WAK3/TAT1, encodes a permease that transports amino acids including leucine and tryptophan, for which our wild-type strain is auxotrophic. This suggests that availability of amino acids may play a key role in anesthetic response. Multiple lines of evidence support this proposal: (i) Deletion or overexpression of permeases that transport leucine and/or tryptophan alters anesthetic response; (ii) prototrophic strains are anesthetic resistant; (iii) altered concentrations of leucine and tryptophan in the medium affect anesthetic response; and (iv) uptake of leucine and tryptophan is inhibited during anesthetic exposure. Not all amino acids are critical for this response since we find that overexpression of the lysine permease does not affect anesthetic sensitivity. These findings are consistent with models in which anesthetics have a physiologically important effect on availability of specific amino acids by altering function of their permeases. In addition, we show that there is a relationship between nutrient availability and ubiquitin metabolism in this response. PMID:12072454

Characterization of interaction between amino acids and fulvic-like organic matter by fluorescence spectroscopy combining thermodynamic calculation.

PubMed

Lin, Tao; Hou, Bingwei; Wang, Jian; Xu, Yaqun; Chen, Wei

2017-03-01

Dissolved organic matter (DOM), as a very fine colloidal suspension, could inevitably affect the transformation process of dissolved organic nitrogen (DON) in drinking water treatment. Tryptophan and tyrosine were used as representatives of DON to investigate the interactions between amino acids and fulvic-like components of fluorescent DOM using titration experiments. The fluorescence intensity decreased significantly with the increasing fulvic acid (FA) concentration, suggesting that FA could greatly quench the intrinsic fluorescence of amino acids such as tryptophan and tyrosine. The absolute spectrum peaks of amino acids (AA) were changed in the presence of FA, possibly being resulted from non-covalent interactions between amino acids and FA. The specific hydrogen bonding and van der Waals forces played dominant roles in the interactions according to the results of theoretical analysis and thermodynamic calculation. The distance between donor and acceptor was 1.25 and 1.14 nm for the FA-tyrosine and FA-tryptophan system, indicating the energy transfer from tyrosine or tryptophan to FA. The association constant (K) decreased with the increase of temperature and pH value, while the change of ionic strength had no obvious influence on K value.

Terahertz spectroscopy of brain tissue from a mouse model of Alzheimer's disease

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Shumyatsky, Pavel; Rodríguez-Contreras, Adrián; Alfano, Robert

2016-01-01

The terahertz (THz) absorption and index of refraction of brain tissues from a mouse model of Alzheimer's disease (AD) and a control wild-type (normal) mouse were compared using THz time-domain spectroscopy (THz-TDS). Three dominating absorption peaks associated to torsional-vibrational modes were observed in AD tissue, at about 1.44, 1.8, and 2.114 THz, closer to the peaks of free tryptophan molecules than in normal tissue. A possible reason is that there is more free tryptophan in AD brain tissue, while in normal brain tissue more tryptophan is attached to other molecules. Our study suggests that THz-absorption modes may be used as an AD biomarker fingerprint in brain, and that THz-TDS is a promising technique for early diagnosis of AD.

Tryptophan-Containing Non-Cationizable Opioid Peptides - a new chemotype with unusual structure and in vivo activity.

PubMed

Marco, Rossella De; Gentilucci, Luca

2017-11-01

Recently, a new family of opioid peptides containing tryptophan came to the spotlight for the absence of the fundamental protonable tyramine 'message' pharmacophore. Structure-activity relationship investigations led to diverse compounds, characterized by different selectivity profiles and agonist or antagonist effects. Substitution at the indole of Trp clearly impacted peripheral/central antinociceptivity. These peculiarities prompted to gather all the compounds in a new class, and to coin the definition 'Tryptophan-Containing Non-Cationizable Opioid Peptides', in short 'TryCoNCOPs'. Molecular docking analysis suggested that the TryCoNCOPs can still interact with the receptors in an agonist-like fashion. However, most TryCoNCOPs showed significant differences between the in vitro and in vivo activities, suggesting that opioid activity may be elicited also via alternative mechanisms.

1,1'-Ethylidenebis[tryptophan] induces pathologic alterations in muscle similar to those observed in the eosinophilia-myalgia syndrome.

PubMed

Emslie-Smith, A M; Mayeno, A N; Nakano, S; Gleich, G J; Engel, A G

1994-12-01

1,1'-Ethylidenebis[tryptophan] (EBT), a derivative of L-tryptophan (LT), is a trace contaminant in batches of LT implicated by epidemiologic evidence in the pathogenesis of the eosinophilia-myalgia syndrome (EMS). We treated female Lewis rats with EBT or unimplicated LT (4 mg per 100 grams daily) by intraperitoneal injection. No rash or weakness occurred in either group. All three EBT rats had a few necrotic muscle fibers. In two rats, perimysium and fascia were abnormally thickened and infiltrated with lymphocytes, macrophages, and sparse eosinophils; two rats had sparse perineurial inflammatory cells. Rats treated with unimplicated LT showed no abnormality. These findings replicate an important feature of human EMS and support the epidemiologic evidence linking EBT to the pathogenesis of the human disease.

Serotonin and Early Cognitive Development: Variation in the Tryptophan Hydroxylase 2 Gene Is Associated with Visual Attention in 7-Month-Old Infants

ERIC Educational Resources Information Center

Leppanen, Jukka M.; Peltola, Mikko J.; Puura, Kaija; Mantymaa, Mirjami; Mononen, Nina; Lehtimaki, Terho

2011-01-01

Background: Allelic variation in the promoter region of a gene that encodes tryptophan hydroxylase isoform 2 (TPH2), a rate-limiting enzyme of serotonin synthesis in the central nervous system, has been associated with variations in cognitive function and vulnerability to affective spectrum disorders. Little is known about the effects of this gene…

Effects of tryptophan depletion on selective serotonin reuptake inhibitor-remitted patients with obsessive compulsive disorder.

PubMed

Hood, Sean D; Broyd, Annabel; Robinson, Hayley; Lee, Jessica; Hudaib, Abdul-Rahman; Hince, Dana A

2017-12-01

Serotonergic antidepressants are first-line medication therapies for obsessive-compulsive disorder, however it is not known if synaptic serotonin availability is important for selective serotonin reuptake inhibitor efficacy. The present study tested the hypothesis that temporary reduction in central serotonin transmission, through acute tryptophan depletion, would result in an increase in anxiety in selective serotonin reuptake inhibitor-remitted obsessive-compulsive disorder patients. Eight patients (four males) with obsessive-compulsive disorder who showed sustained clinical improvement with selective serotonin reuptake inhibitor treatment underwent acute tryptophan depletion in a randomized, double-blind, placebo-controlled, within-subjects design, over two days one week apart. Five hours after consumption of the depleting/sham drink the participants performed a personalized obsessive-compulsive disorder symptom exposure task. Psychological responses were measured using the Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and Visual Analogue Scales. Free plasma tryptophan to large neutral amino acid ratio decreased by 93% on the depletion day and decreased by 1% on the sham day, as anticipated. Psychological rating scores as measured by Visual Analogue Scale showed a significant decrease in perceived control and increase in interfering thoughts at the time of provocation on the depletion day but not on the sham day. A measure of convergent validity, namely Visual Analogue Scale Similar to past, was significantly higher at the time of provocation on both the depletion and sham days. Both the depletion and time of provocation scores for Visual Analogue Scale Anxiety, Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and blood pressure were not significant. Acute tryptophan depletion caused a significant decrease in perceived control and increase in interfering thoughts at the time of provocation. Acute tryptophan depletion had no effect on the Spielberger State Anxiety Inventory or Visual Analogue Scale Anxiety measures, which suggests that the mechanism of action of selective serotonin reuptake inhibitors may be different to that seen in panic, social anxiety and post-traumatic stress disorder. Successful selective serotonin reuptake inhibitor treatment of obsessive-compulsive disorder may involve the ability of serotonin to switch habitual responding to goal-directed behaviour.

[Changes in brain serotonin biosynthesis in rats with diabetes mellitus induced by streptozocin: effect of insulin treatment].

PubMed

Manjarrez-Gutiérrez, G; Rocío Herrera-Márquez, J R; Bueno-Santoyo, S; González-Ramírez, M; Hernández, J

2000-01-01

To investigate if the changes in the activity of the tryptophan-5-hydroxylase and in brain serotonin synthesis provoked by diabetes mellitus persist or return to normal in the diabetic rats submitted to treatment with insulin. Diabetes induced by the administration of streptozotocin in rats and their treatment with insulin was the paradigm used. At days 7, 14 and 21 of evolution, the brain serotonergic biosynthetic activity was evaluated. The diabetic rats showed a significant decrease of body weight. Also, they showed a low concentration of I-tryptophan, as well as a diminution in the activity of the key enzyme tryptophan-5-hydroxylase and its product serotonin in the cerebral cortex and brainstem. Interestingly, the activity of the enzyme was higher in the brainstem from day 14, accompanied with an elevation of the neurotransmitter. The diabetic rats submitted to treatment with insulin showed a complete physical recovery and a return to normal of plasma and brain I-tryptophan. The activity of the enzyme not only normalized but was elevated and with an increase of serotonin in the brainstem and cerebral cortex. The present findings confirm that diabetes mellitus produced a chronic anabolic deficit and a decrease in some brain regions of serotonin synthesis. Also, demonstrate that the diabetic rats under specific treatment with insulin had a complete physical recovery and a return to normal of the serotonin precursor in the blood and brain. However, the activity of the limiting enzyme TrpOH case was elevated with an increase of the neurotransmitter in all regions studied. Since the diabetic animal, insulin treated, does recover metabolically, the mechanism of activation of the serotonin biosynthetic path in the brain may not be dependent on the decreased availability of its precursor the free plasma I-tryptophan. Instead, it might be due to a change in the kinetics of tryptophan-5-hydroxylase, since its activity remains significantly increased in spite of plasma and brain normalization of its substrate. Altogether these changes in the biosynthesis of an important brain neurotransmitter may be of relevance in the pathophysiology of the psychoneurological complications in diabetic patients.

Impact of endophytic colonization patterns on Zamioculcas zamiifolia stress response and in regulating ROS, tryptophan and IAA levels under airborne formaldehyde and formaldehyde-contaminated soil conditions.

PubMed

Khaksar, Gholamreza; Treesubsuntorn, Chairat; Thiravetyan, Paitip

2017-05-01

Deeper understanding of plant-endophyte interactions under abiotic stress would provide new insights into phytoprotection and phytoremediation enhancement. Many studies have investigated the positive role of plant-endophyte interactions in providing protection to the plant against pollutant stress through auxin (indole-3-acetic acid (IAA)) production. However, little is known about the impact of endophytic colonization patterns on plant stress response in relation to reactive oxygen species (ROS) and IAA levels. Moreover, the possible effect of pollutant phase on plant stress response is poorly understood. Here, we elucidated the impact of endophytic colonization patterns on plant stress response under airborne formaldehyde compared to formaldehyde-contaminated soil. ROS, tryptophan and IAA levels in the roots and shoots of endophyte-inoculated and non-inoculated plants in the presence and absence of formaldehyde were measured. Strain-specific quantitative polymerase chain reaction (qPCR) was used to investigate dynamics of endophyte colonization. Under the initial exposure to airborne formaldehyde, non-inoculated plants accumulated more tryptophan in the shoots (compared to the roots) to synthesize IAA. However, endophyte-inoculated plants behaved differently as they synthesized and accumulated more tryptophan in the roots and, hence, higher levels of IAA accumulation and exudation within roots which might act as a signaling molecule to selectively recruit B. cereus ERBP. Under continuous airborne formaldehyde stress, higher levels of ROS accumulation in the shoots pushed the plant to synthesize more tryptophan and IAA in the shoots (compared to the roots). Higher levels of IAA in the shoots might act as the potent driving force to relocalize B. cereus ERBP from roots to the shoots. In contrast, under formaldehyde-contaminated soil, B. cereus ERBP colonized root tissues without moving to the shoots since there was a sharp increase in ROS, tryptophan and IAA levels of the roots without any significant increase in the shoots. Pollutant phase affected endophytic colonization patterns and plant stress responses differently. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Modulation of central serotonin affects emotional information processing in impulsive aggressive personality disorder.

PubMed

Lee, Royce J; Gill, Andrew; Chen, Bing; McCloskey, Michael; Coccaro, Emil F

2012-06-01

The mechanistic model whereby serotonin affects impulsive aggression is not completely understood. The purpose of this study was to test the hypothesis that depletion of serotonin reserves by tryptophan depletion affects emotional information processing in susceptible individuals. The effect of tryptophan (vs placebo) depletion on processing of Ekman emotional faces was compared in impulsive aggressive personality disordered, male and female adults with normal controls. All subjects were free of psychotropic medications, medically healthy, nondepressed, and substance free. Additionally, subjective mood state and vital signs were monitored. For emotion recognition, a significant interaction of Aggression × Drug × Sex (F(1, 31) = 7.687, P = 0.009) was found, with male normal controls but not impulsive aggressive males showing increased recognition of fear. For intensity ratings of emotional faces, a significant interaction was discovered of Drug × Group × Sex (F(1, 31) = 5.924, P = 0.021), with follow-up tests revealing that males with intermittent explosive disorder tended to increase intensity ratings of angry faces after tryptophan depletion. Additionally, tryptophan depletion was associated with increased heart rate in all subjects, and increased intensity of the subjective emotional state of "anger" in impulsive aggressive subjects. Individuals with clinically relevant levels of impulsive aggression may be susceptible to effects of serotonergic depletion on emotional information processing, showing a tendency to exaggerate their impression of the intensity of angry expressions and to report an angry mood state after tryptophan depletion. This may reflect heightened sensitivity to the effects of serotonergic dysregulation, and suggests that what underlies impulsive aggression is either supersensitivity to serotonergic disturbances or susceptibility to fluctuations in central serotonergic availability.

Neural and behavioral responses to tryptophan depletion in unmedicated patients with remitted major depressive disorder and controls.

PubMed

Neumeister, Alexander; Nugent, Allison C; Waldeck, Tracy; Geraci, Marilla; Schwarz, Markus; Bonne, Omer; Bain, Earle E; Luckenbaugh, David A; Herscovitch, Peter; Charney, Dennis S; Drevets, Wayne C

2004-08-01

An instructive paradigm for investigating the relationship between brain serotonin function and major depressive disorder (MDD) is the response to tryptophan depletion (TD) induced by oral loading with all essential amino acids except the serotonin precursor tryptophan. To determine whether serotonin dysfunction represents a trait abnormality in MDD in the context of specific neural circuitry abnormalities involved in the pathogenesis of MDD. Randomized double-blind crossover study. Outpatient clinic. Twenty-seven medication-free patients with remitted MDD (18 women and 9 men; mean +/- SD age, 39.8 +/- 12.7 years) and 19 controls (10 women and 9 men; mean +/- SD age, 34.4 +/- 11.5 years). We induced TD by administering capsules containing an amino acid mixture without tryptophan. Sham depletion used identical capsules containing hydrous lactose. Fluorodeoxyglucose F 18 positron emission tomography studies were performed 6 hours after TD. Magnetic resonance images were obtained for all participants. Quantitative positron emission tomography of regional cerebral glucose utilization to study the neural effects of sham depletion and TD. Behavioral assessments used a modified (24-item) version of the Hamilton Depression Rating Scale. Tryptophan depletion induced a transient return of depressive symptoms in patients with remitted MDD but not in controls (P<.001). Compared with sham depletion, TD was associated with an increase in regional cerebral glucose utilization in the orbitofrontal cortex, medial thalamus, anterior and posterior cingulate cortices, and ventral striatum in patients with remitted MDD but not in controls. The pattern of TD-induced regional cerebral glucose utilization changes in patients with remitted MDD suggests that TD unmasks a disease-specific, serotonin system-related trait dysfunction and identifies a circuit that probably plays a key role in the pathogenesis of MDD.

Role of block copolymer-micelle nanocomposites in dye-bovine serum albumin binding: a combined experimental and molecular docking study.

PubMed

Manna, Anamika; Chakravorti, Sankar

2013-02-02

The role of a nanocomposite (NC), composed of intercalation of the diblock copolymer polyethylene-b-polyethylene glycol (PE-b-PEG) with the anionic surfactant sodium dodecyl sulphate (SDS), on the binding characteristics of bovine serum albumin (BSA) with a dye (1,8-naphthalimide, NAPMD) compared to the interaction between the same players in aqueous solution has been examined comprehensively in this paper. Static quenching due to complex formation in both NC medium and in buffer solution has been inferred on the basis of considerable changes in the absorption spectra of BSA on addition of NAPMD, of which the interaction is found to be stronger in NC medium. Temperature dependent fluorescence data also confirm an effective static quenching and stronger binding of NAPMD with BSA in NC medium. Peptide chain unfolding and denaturing of BSA in NC medium have been confirmed from steady state and time-resolved emission and circular dichroism data. This exposes both the tyrosine and tryptophan moieties as a unique case. Increased energy transfer between NAPMD and the tryptophan residue in the unfolded form of BSA helps in the appearance of tyrosine fluorescence in NC medium by quenching the tryptophan band. Ionization of the hydroxyl group in the aromatic ring of the tyrosine residue by the PEG group present in the NC medium produces a downshift of the tyrosine fluorescence band. The use of site selective markers confirms that NAPMD is near tryptophan in Sudlow's site I in NC medium and in buffer solution it is away from tryptophan in Sudlow's site II. The theoretical docking studies also vindicate the results of binding of NAPMD with BSA in site I or site II in NC and buffer media, as observed from different emission experiments including the site selective markers study.

Bile Acids and Tryptophan Metabolism Are Novel Pathways Involved in Metabolic Abnormalities in BPA-Exposed Pregnant Mice and Male Offspring.

PubMed

Susiarjo, Martha; Xin, Frances; Stefaniak, Martha; Mesaros, Clementina; Simmons, Rebecca A; Bartolomei, Marisa S

2017-08-01

Increasing evidence has demonstrated that exposure to endocrine-disrupting chemicals impacts maternal and fetal health, but the underlying mechanisms are still unclear. We previously showed that dietary exposure to 10 µg/kg body weight (bw)/d and 10 mg/kg bw/d of bisphenol A (BPA) during pregnancy induced metabolic abnormalities in F1 male offspring and gestational glucose intolerance in F0 pregnant mice. The aim of this study was to elucidate the underlying etiologies of BPA exposure-induced metabolic disease by analyzing the male fetal liver metabolome. Using the Metabolon Discover HD4 Platform, our laboratory identified metabolic pathways that were altered by BPA exposure, including biochemicals in lipid and amino acid metabolism. Specifically, primary and secondary bile acids were increased in liver from BPA-exposed embryonic day 18.5 male fetuses. We subsequently showed that increased bile acid was associated with a defective farnesoid X receptor-dependent negative feedback mechanism in BPA-exposed fetuses. In addition, through metabolomics, we observed that BPA-exposed fetuses had elevated tryptophan levels. Independent liquid chromatography and mass spectrometry measurement revealed that BPA-exposed dams also had increased tryptophan levels relative to those of controls. Because several key enzymes in tryptophan catabolism are vitamin B6 dependent and vitamin B6 deficiencies have been linked to gestational diabetes, we tested the impact of vitamin B6 supplementation and showed that it rescued gestational glucose intolerance in BPA-exposed pregnant mice. Our study has therefore identified two pathways (bile acid and tryptophan metabolism) that potentially underlie BPA-induced maternal and fetal metabolic disease. Copyright © 2017 Endocrine Society.

Serum Levels of Tryptophan, 5-Hydroxytryptophan and Serotonin in Patients Affected with Different Forms of Amenorrhea

PubMed Central

Comai, S.; Bertazzo, A.; Carretti, N.; Podfigurna-Stopa, A.; Luisi, S.; Costa, C.V.L.

2010-01-01

Tryptophan (Trp) is present in the serum, partly bound to albumine and in the free form. The unbound portion of circulating tryptophan has the property of crossing the hematoencephalic barrier and being converted within the brain into serotonin (5-HT) through the enzymatic processes of hydroxylation and decarboxylation. The serotoninergic system plays an important role in neuroendocrine control of reproductive hormone secretion, and in particular, it may influence GnRH pulsatility, a function essential for reproductive processes. In this study, we analysed serum levels of tryptophan, serotonin and 5-hydroxytryptophan (5-HTP) in women with three different forms of amenorrhea: 16 patients were diagnosed with anorexia nervosa, 60 patients with functional hypothalamic amenorrhea, and 14 patients with hyperprolactinemia. Data were compared with those of a group of 25 healthy women. Serum Trp levels were significantly (P ≤ 0.05) lower in the anorexic (11.64 ± 0.53 μg/ml, mean ± S.E.) than in the control (12.98 ± 0.37 μg/ml) groups. In addition, in the anorexic group a statistical dispersion of Trp values was shown indicating a bimodal data distribution suggesting the existence of two different subgroups of patients. Regarding 5-HTP, an increase of its serum level was observed in all the groups with amenorrhea with the highest value in hyperprolactinemic patients. On the contrary, no statistical differences in serum 5-HT levels among the four analyzed groups were observed. This study shows that women affected by various forms of amenorrhea present an altered metabolism of tryptophan via serotonin and, in particular, markedly high differences are observed between the two subgroups of anorexic patients. PMID:22084589

Indoleamine 2,3-dioxygenase 1 deficiency attenuates CCl4-induced fibrosis through Th17 cells down-regulation and tryptophan 2,3-dioxygenase compensation

PubMed Central

Zhou, Zhenting; Lin, Haiyan; Chen, Chun; Huang, Peng; Huang, Weiliang; Zhou, Chuying; Huang, Shaohui; Nie, Linghui; Liu, Ye; Chen, Youming; Zhou, Daqiao; Lv, Zhiping

2017-01-01

Indoleamine 2,3-dioxygenase 1 (IDO1) is an intracellular rate-limiting enzyme in the metabolism of tryptophan along the kynurenine pathway, subsequently mediating the immune response; however, the role of IDO1 in liver fibrosis and cirrhosis is still unclear. In this study, we investigated the role of IDO1 in the development of hepatic fibrosis and cirrhosis. Patients with hepatitis B virus-induced cirrhosis and healthy volunteers were enrolled. For animals, carbon tetrachloride (CCl4) was used to establish liver fibrosis in wild-type and IDO1 knockout mice. Additionally, an IDO1 inhibitor (1-methyl-D-tryptophan) was administered to WT fibrosis mice. Liver lesions were positively correlated with serum IDO1 levels in both the clinical subjects and hepatic fibrosis mice. A positive correlation between serum IDO1 levels and liver stiffness values was found in the cirrhosis patients. Notably, IDO1 knockout mice were protected from CCl4-induced liver fibrosis, as reflected by unchanged serum alanine transaminase and aspartate transaminase levels and lower collagen deposition, α-smooth muscle actin expression and apoptotic cell death rates. On the other hand, tryptophan 2,3-dioxygenase (TDO), another systemic tryptophan metabolism enzyme, exhibited a compensatory increase as a result of IDO1 deficiency. Moreover, hepatic interleukin-17a, a characteristic cytokine of T helper 17 (Th17) cells, and downstream cytokines’ mRNA levels showed lower expression in the IDO1–/– model mice. IDO1 appears to be a potential hallmark of liver lesions, and its deficiency protects mice from CCl4-induced fibrosis mediated by Th17 cells down-regulation and TDO compensation. PMID:28465467

Fluorometric titration approach for calibration of quantity of binding site of purified monoclonal antibody recognizing epitope/hapten nonfluorescent at 340 nm.

PubMed

Yang, Xiaolan; Hu, Xiaolei; Xu, Bangtian; Wang, Xin; Qin, Jialin; He, Chenxiong; Xie, Yanling; Li, Yuanli; Liu, Lin; Liao, Fei

2014-06-17

A fluorometric titration approach was proposed for the calibration of the quantity of monoclonal antibody (mcAb) via the quench of fluorescence of tryptophan residues. It applied to purified mcAbs recognizing tryptophan-deficient epitopes, haptens nonfluorescent at 340 nm under the excitation at 280 nm, or fluorescent haptens bearing excitation valleys nearby 280 nm and excitation peaks nearby 340 nm to serve as Förster-resonance-energy-transfer (FRET) acceptors of tryptophan. Titration probes were epitopes/haptens themselves or conjugates of nonfluorescent haptens or tryptophan-deficient epitopes with FRET acceptors of tryptophan. Under the excitation at 280 nm, titration curves were recorded as fluorescence specific for the FRET acceptors or for mcAbs at 340 nm. To quantify the binding site of a mcAb, a universal model considering both static and dynamic quench by either type of probes was proposed for fitting to the titration curve. This was easy for fitting to fluorescence specific for the FRET acceptors but encountered nonconvergence for fitting to fluorescence of mcAbs at 340 nm. As a solution, (a) the maximum of the absolute values of first-order derivatives of a titration curve as fluorescence at 340 nm was estimated from the best-fit model for a probe level of zero, and (b) molar quantity of the binding site of the mcAb was estimated via consecutive fitting to the same titration curve by utilizing such a maximum as an approximate of the slope for linear response of fluorescence at 340 nm to quantities of the mcAb. This fluorometric titration approach was proved effective with one mcAb for six-histidine and another for penicillin G.

Localization of the human indoleamine 2,3-dioxygenase (IDO) gene to the pericentromeric region of human chromosome 8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkin, D.J.; Jones, C.; Kimbro, K.S.

1993-07-01

Indoleamine 2,3-dioxygenase (IDO) is the first enzyme in the catabolic pathway for tryptophan. This extrahepatic enzyme differs from the hepatic enzyme, tryptophan 2,3-dioxygenase (TDO), in molecular as well as enzymatic characteristics, although both enzymes catalyze the same reaction: cleavage of tryptophan into N-formylkynurenine. The induction of IDO by IFN-[gamma] plays a role in the antigrowth effect of IFN-[gamma] in cell cultures and in the inhibition of intracellular pathogens, e.g., Toxoplasma gondii and Chlamydia psittaci. Tryptophan is also the precursor for the synthesis of serotonin, and reduced levels of tryptophan and serotonin found in AIDS patients have been correlated with themore » presence of IFN-[gamma] and consequent elevation of IDO activity. The IDO enzyme has been purified and characterized, and its cDNA and genomic DNA clones have been isolated and analyzed. DNA from hybrid cells containing fragments of human chromosome 8 was used to determine the regional localization of the IDO gene on chromosome 8. The hybrids R30-5B and R30-2A contain 8p11 [yields] qter and 8q13 [yields] qter, respectively. Hybrid 229-3A contains the 8pter [yields] q11. The hybrid R30-2A was negative for the IDO gene, whereas R30-5B and 229-3A were positive as analyzed by PCR and verified by Southern blotting. Only the region close to the centromere is shared by R30-5B and 229-3A hybrids. The results indicate that the IDO gene is located on chromosome 8p11 [yields] q11.« less

Effects of acute tryptophan depletion on central processing of CT-targeted and discriminatory touch in humans.

PubMed

Trotter, Paula Diane; McGlone, Francis; McKie, Shane; McFarquhar, Martyn; Elliott, Rebecca; Walker, Susannah Claire; Deakin, John Francis William

2016-08-01

C-tactile afferents (CTs) are slowly conducting nerve fibres, present only in hairy skin. They are optimally activated by slow, gentle stroking touch, such as those experienced during a caress. CT stimulation activates affective processing brain regions, alluding to their role in affective touch perception. We tested a theory that CT-activating touch engages the pro-social functions of serotonin, by determining whether reducing serotonin, through acute tryptophan depletion, diminishes subjective pleasantness and affective brain responses to gentle touch. A tryptophan depleting amino acid drink was administered to 16 healthy females, with a further 14 receiving a control drink. After 4 h, participants underwent an fMRI scan, during which time CT-innervated forearm skin and CT non-innervated finger skin was stroked with three brushes of differing texture, at CT-optimal force and velocity. Pleasantness ratings were obtained post scanning. The control group showed a greater response in ipsilateral orbitofrontal cortex to CT-activating forearm touch compared to touch to the finger where CTs are absent. This differential response was not present in the tryptophan depleted group. This interaction effect was significant. In addition, control participants showed a differential primary somatosensory cortex response to brush texture applied to the finger, a purely discriminatory touch response, which was not observed in the tryptophan depleted group. This interaction effect was also significant. Pleasantness ratings were similar across treatment groups. These results implicate serotonin in the differentiation between CT-activating and purely discriminatory touch responses. Such effects could contribute to some of the social abnormalities seen in psychiatric disorders associated with abnormal serotonin function. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Albugo-imposed changes to tryptophan-derived antimicrobial metabolite biosynthesis may contribute to suppression of non-host resistance to Phytophthora infestans in Arabidopsis thaliana.

PubMed

Prince, David C; Rallapalli, Ghanasyam; Xu, Deyang; Schoonbeek, Henk-Jan; Çevik, Volkan; Asai, Shuta; Kemen, Eric; Cruz-Mireles, Neftaly; Kemen, Ariane; Belhaj, Khaoula; Schornack, Sebastian; Kamoun, Sophien; Holub, Eric B; Halkier, Barbara A; Jones, Jonathan D G

2017-03-20

Plants are exposed to diverse pathogens and pests, yet most plants are resistant to most plant pathogens. Non-host resistance describes the ability of all members of a plant species to successfully prevent colonization by any given member of a pathogen species. White blister rust caused by Albugo species can overcome non-host resistance and enable secondary infection and reproduction of usually non-virulent pathogens, including the potato late blight pathogen Phytophthora infestans on Arabidopsis thaliana. However, the molecular basis of host defense suppression in this complex plant-microbe interaction is unclear. Here, we investigate specific defense mechanisms in Arabidopsis that are suppressed by Albugo infection. Gene expression profiling revealed that two species of Albugo upregulate genes associated with tryptophan-derived antimicrobial metabolites in Arabidopsis. Albugo laibachii-infected tissue has altered levels of these metabolites, with lower indol-3-yl methylglucosinolate and higher camalexin accumulation than uninfected tissue. We investigated the contribution of these Albugo-imposed phenotypes to suppression of non-host resistance to P. infestans. Absence of tryptophan-derived antimicrobial compounds enables P. infestans colonization of Arabidopsis, although to a lesser extent than Albugo-infected tissue. A. laibachii also suppresses a subset of genes regulated by salicylic acid; however, salicylic acid plays only a minor role in non-host resistance to P. infestans. Albugo sp. alter tryptophan-derived metabolites and suppress elements of the responses to salicylic acid in Arabidopsis. Albugo sp. imposed alterations in tryptophan-derived metabolites may play a role in Arabidopsis non-host resistance to P. infestans. Understanding the basis of non-host resistance to pathogens such as P. infestans could assist in development of strategies to elevate food security.

Senescence-Induced Serotonin Biosynthesis and Its Role in Delaying Senescence in Rice Leaves1[C][W][OA

PubMed Central

Kang, Kiyoon; Kim, Young-Soon; Park, Sangkyu; Back, Kyoungwhan

2009-01-01

Serotonin, which is well known as a pineal hormone in mammals, plays a key role in conditions such as mood, eating disorders, and alcoholism. In plants, although serotonin has been suggested to be involved in several physiological roles, including flowering, morphogenesis, and adaptation to environmental changes, its regulation and functional roles are as yet not characterized at the molecular level. In this study, we found that serotonin is greatly accumulated in rice (Oryza sativa) leaves undergoing senescence induced by either nutrient deprivation or detachment, and its synthesis is closely coupled with transcriptional and enzymatic induction of the tryptophan biosynthetic genes as well as tryptophan decarboxylase (TDC). Transgenic rice plants that overexpressed TDC accumulated higher levels of serotonin than the wild type and showed delayed senescence of rice leaves. However, transgenic rice plants, in which expression of TDC was suppressed through an RNA interference (RNAi) system, produced less serotonin and senesced faster than the wild type, suggesting that serotonin is involved in attenuating leaf senescence. The senescence-retarding activity of serotonin is associated with its high antioxidant activity compared to either tryptophan or chlorogenic acid. Results of TDC overexpression and TDC RNAi plants suggest that TDC plays a rate-limiting role for serotonin accumulation, but the synthesis of serotonin depends on an absolute amount of tryptophan accumulation by the coordinate induction of the tryptophan biosynthetic genes. In addition, immunolocalization analysis revealed that serotonin was abundant in the vascular parenchyma cells, including companion cells and xylem-parenchyma cells, suggestive of its involvement in maintaining the cellular integrity of these cells for facilitating efficient nutrient recycling from senescing leaves to sink tissues during senescence. PMID:19439571

A link between central kynurenine metabolism and bone strength in rats with chronic kidney disease

PubMed Central

Pawlak, Krystyna; Oksztulska-Kolanek, Ewa; Domaniewski, Tomasz; Znorko, Beata; Karbowska, Malgorzata; Citkowska, Aleksandra; Rogalska, Joanna; Roszczenko, Alicja; Brzoska, Malgorzata M.; Pawlak, Dariusz

2017-01-01

Background Disturbances in mineral and bone metabolism represent one of the most complex complications of chronic kidney disease (CKD). Serotonin, a monoamine synthesized from tryptophan, may play a potential role in bone metabolism. Brain-derived serotonin exerts a positive effect on the bone structure by limiting bone resorption and enhancing bone formation. Tryptophan is the precursor not only to the serotonin but also and primarily to kynurenine metabolites. The ultimate aim of the present study was to determine the association between central kynurenine metabolism and biomechanical as well as geometrical properties of bone in the experimental model of the early stage of CKD. Methods Thirty-three Wistar rats were randomly divided into two groups (sham-operated and subtotal nephrectomized animals). Three months after surgery, serum samples were obtained for the determination of biochemical parameters, bone turnover biomarkers, and kynurenine pathway metabolites; tibias were collected for bone biomechanical, bone geometrical, and bone mass density analysis; brains were removed and divided into five regions for the determination of kynurenine pathway metabolites. Results Subtotal nephrectomized rats presented higher serum concentrations of creatinine, urea nitrogen, and parathyroid hormone, and developed hypocalcemia. Several biomechanical and geometrical parameters were significantly elevated in rats with experimentally induced CKD. Subtotal nephrectomized rats presented significantly higher kynurenine concentrations and kynurenine/tryptophan ratio and significantly lower tryptophan levels in all studied parts of the brain. Kynurenine in the frontal cortex and tryptophan in the hypothalamus and striatum correlated positively with the main parameters of bone biomechanics and bone geometry. Discussion In addition to the complex mineral, hormone, and metabolite changes, intensified central kynurenine turnover may play an important role in the development of bone changes in the course of CKD. PMID:28439468

Structure and reactivity of the distonic and aromatic radical cations of tryptophan.

PubMed

Piatkivskyi, Andrii; Osburn, Sandra; Jaderberg, Kendall; Grzetic, Josipa; Steill, Jeffrey D; Oomens, Jos; Zhao, Junfang; Lau, Justin Kai-Chi; Verkerk, Udo H; Hopkinson, Alan C; Siu, K W Michael; Ryzhov, Victor

2013-04-01

In this work, we regiospecifically generate and compare the gas-phase properties of two isomeric forms of tryptophan radical cations-a distonic indolyl N-radical (H3N(+) - TrpN(•)) and a canonical aromatic π (Trp(•+)) radical cation. The distonic radical cation was generated by nitrosylating the indole nitrogen of tryptophan in solution followed by collision-induced dissociation (CID) of the resulting protonated N-nitroso tryptophan. The π-radical cation was produced via CID of the ternary [Cu(II)(terpy)(Trp)](•2+) complex. CID spectra of the two isomeric species were found to be very different, suggesting no interconversion between the isomers. In gas-phase ion-molecule reactions, the distonic radical cation was unreactive towards n-propylsulfide, whereas the π radical cation reacted by hydrogen atom abstraction. DFT calculations revealed that the distonic indolyl radical cation is about 82 kJ/mol higher in energy than the π radical cation of tryptophan. The low reactivity of the distonic nitrogen radical cation was explained by spin delocalization of the radical over the aromatic ring and the remote, localized charge (at the amino nitrogen). The lack of interconversion between the isomers under both trapping and CID conditions was explained by the high rearrangement barrier of ca.137 kJ/mol. Finally, the two isomers were characterized by infrared multiple-photon dissociation (IRMPD) spectroscopy in the ~1000-1800 cm(-1) region. It was found that some of the main experimental IR features overlap between the two species, making their distinction by IRMPD spectroscopy in this region problematic. In addition, DFT theoretical calculations showed that the IR spectra are strongly conformation-dependent.

Significance of two distinct types of tryptophan synthase beta chain in Bacteria, Archaea and higher plants.

PubMed

Xie, Gary; Forst, Christian; Bonner, Carol; Jensen, Roy A

2002-01-01

Tryptophan synthase consists of two subunits, alpha and beta. Two distinct subgroups of beta chain exist. The major group (TrpEb_1) includes the well-studied beta chain of Salmonella typhimurium. The minor group of beta chain (TrpEb_2) is most frequently found in the Archaea. Most of the amino-acid residues important for catalysis are highly conserved between both TrpE subfamilies. Conserved amino-acid residues of TrpEb_1 that make allosteric contact with the TrpEa subunit (the alpha chain) are absent in TrpEb_2. Representatives of Archaea, Bacteria and higher plants all exist that possess both TrpEb_1 and TrpEb_2. In those prokaryotes where two trpEb genes coexist, one is usually trpEb_1 and is adjacent to trpEa, whereas the second is trpEb_2 and is usually unlinked with other tryptophan-pathway genes. TrpEb_1 is nearly always partnered with TrpEa in the tryptophan synthase reaction. However, by default at least six lineages of the Archaea are likely to use TrpEb_2 as the functional beta chain, as TrpEb_1 is absent. The six lineages show a distinctive divergence within the overall TrpEa phylogenetic tree, consistent with the lack of selection for amino-acid residues in TrpEa that are otherwise conserved for interfacing with TrpEb_1. We suggest that the standalone function of TrpEb_2 might be to catalyze the serine deaminase reaction, an established catalytic capability of tryptophan synthase beta chains. A coincident finding of interest is that the Archaea seem to use the citramalate pathway, rather than threonine deaminase (IlvA), to initiate the pathway of isoleucine biosynthesis.

Metabolite profile analysis reveals functional effects of 28-day vitamin B-6 restriction on one-carbon metabolism and tryptophan catabolic pathways in healthy men and women.

PubMed

da Silva, Vanessa R; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A; Midttun, Øivind; Quinlivan, Eoin P; Garrett, Timothy J; Coats, Bonnie; Shankar, Meena N; Percival, Susan S; Chi, Yueh-Yun; Muller, Keith E; Ueland, Per Magne; Stacpoole, Peter W; Gregory, Jesse F

2013-11-01

Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5'-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (<0.35 mg/d). liquid chromatography-tandem mass spectrometry analysis of the compounds relevant to one-carbon metabolism showed that vitamin B-6 restriction yielded increased cystathionine (53% pre- and 76% postprandial; P < 0.0001) and serine (12% preprandial; P < 0.05), and lower creatine (40% pre- and postprandial; P < 0.0001), creatinine (9% postprandial; P < 0.05), and dimethylglycine (16% postprandial; P < 0.05) relative to the vitamin B-6-adequate state. In the tryptophan pathway, vitamin B-6 restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P < 0.01) and higher 3-hydroxykynurenine (39% pre- and 34% postprandial; P < 0.01). Multivariate ANOVA analysis showed a significant global effect of vitamin B-6 restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency.

High stability and biological activity of the copper(II) complexes of alloferon 1 analogues containing tryptophan.

PubMed

Kadej, Agnieszka; Kuczer, Mariola; Czarniewska, Elżbieta; Urbański, Arkadiusz; Rosiński, Grzegorz; Kowalik-Jankowska, Teresa

2016-10-01

Copper(II) complex formation processes between the alloferon 1 (Allo1) (HGVSGHGQHGVHG) analogues where the tryptophan residue is introducing in the place His residue H1W, H6W, H9W and H12W have been studied by potentiometric, UV-visible, CD and EPR spectroscopic, and MS methods. For all analogues of alloferon 1 complex speciation have been obtained for a 1:1 metal-to-ligand molar ratio and 2:1 of H1W because of precipitation at higher (2:1, 3:1 and 4:1) ratios. At physiological pH7.4 and a 1:1 metal-to-ligand molar ratio the tryptophan analogues of alloferon 1 form the CuH -1 L and/or CuH -2 L complexes with the 4N binding mode. The introduction of tryptophan in place of histidine residues changes the distribution diagram of the complexes formed with the change of pH and their stability constants compared to the respective substituted alanine analogues of alloferon 1. The CuH -1 L, CuH -2 L and CuH -3 L complexes of the tryptophan analogues are more stable from 1 to 5 log units in comparison to those of the alanine analogues. This stabilization of the complexes may result from cation(Cu(II))-π and indole/imidazole ring interactions. The induction of apoptosis in vivo, in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active were the H12W peptide and Cu(II)-H12W complex formed at pH7.4. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of fluoxetine and 1-methyl-L-tryptophan in treatment of depression-like illness in Bacillus Calmette-Guerin-induced inflammatory model of depression in mice.

PubMed

Rana, Proteesh; Sharma, Amit K; Jain, Smita; Deshmukh, Pravin; Bhattacharya, S K; Banerjee, B D; Mediratta, Pramod K

2016-11-01

The inflammatory response system has been implicated in the pathophysiology of major depression. The pro-inflammatory cytokines like interferon-γ induce the enzyme indoleamine-2,3-dioxygenase (IDO) of the kynurenine pathway of tryptophan metabolism. The induction of IDO reduces the availability of tryptophan for serotonin synthesis. Furthermore, the metabolites of kynurenine pathway have neurotoxic property, which along with decreased serotonin may account for depression-like illness. The aim of this study was to compare the effects of treatment with fluoxetine and 1-methyl-L-tryptophan (1-MT) on Bacillus Calmette-Guerin (BCG)-induced inflammatory model of depression in mice. Behavioral tests included locomotor activity, forced swim test (FST) and tail suspension test (TST). Oxidative stress was assessed by examining the levels of thiobarbituric acid reactive species (TBARS) and non-protein thiols (NP-SH) in homogenized whole brain samples. Comet assays were performed to assess neurotoxicity. The results of this study demonstrate that BCG treatment resulted in an increase in duration of immobility in FST and TST as compared to the saline group. Further, it produced a significant increase in the brain TBARS levels and decrease in the brain NP-SH levels. The hippocampal tissue from BCG group had significantly more comet cells than the saline group. 1-MT and fluoxetine were able to reverse the BCG-induced depression-like behavior and the derangement in oxidative stress parameters. Fluoxetine and 1-MT also reversed the BCG-induced neurotoxicity in such mice. 1-Methyl-L-tryptophan exhibits antidepressant-like effect comparable to that of fluoxetine in treating BCG-induced depression-like behavior in mice.

Serotonin and Social Norms

PubMed Central

Bilderbeck, Amy C.; Brown, Gordon D. A.; Read, Judi; Woolrich, Mark; Cowen, Phillip J.; Behrens, Tim E. J.

2014-01-01

How do people sustain resources for the benefit of individuals and communities and avoid the tragedy of the commons, in which shared resources become exhausted? In the present study, we examined the role of serotonin activity and social norms in the management of depletable resources. Healthy adults, alongside social partners, completed a multiplayer resource-dilemma game in which they repeatedly harvested from a partially replenishable monetary resource. Dietary tryptophan depletion, leading to reduced serotonin activity, was associated with aggressive harvesting strategies and disrupted use of the social norms given by distributions of other players’ harvests. Tryptophan-depleted participants more frequently exhausted the resource completely and also accumulated fewer rewards than participants who were not tryptophan depleted. Our findings show that rank-based social comparisons are crucial to the management of depletable resources, and that serotonin mediates responses to social norms. PMID:24815611

Stochastic thermodynamics of a chemical nanomachine: The channeling enzyme tryptophan synthase.

PubMed

Loutchko, Dimitri; Eisbach, Maximilian; Mikhailov, Alexander S

2017-01-14

The enzyme tryptophan synthase is characterized by a complex pattern of allosteric interactions that regulate the catalytic activity of its two subunits and opening or closing of their ligand gates. As a single macromolecule, it implements 13 different reaction steps, with an intermediate product directly channeled from one subunit to another. Based on experimental data, a stochastic model for the operation of tryptophan synthase has been earlier constructed [D. Loutchko, D. Gonze, and A. S. Mikhailov, J. Phys. Chem. B 120, 2179 (2016)]. Here, this model is used to consider stochastic thermodynamics of such a chemical nanomachine. The Gibbs energy landscape of the internal molecular states is determined, the production of entropy and its flow within the enzyme are analyzed, and the information exchange between the subunits resulting from allosteric cross-regulations and channeling is discussed.

Tyrosine- and tryptophan-coated gold nanoparticles inhibit amyloid aggregation of insulin.

PubMed

Dubey, Kriti; Anand, Bibin G; Badhwar, Rahul; Bagler, Ganesh; Navya, P N; Daima, Hemant Kumar; Kar, Karunakar

2015-12-01

Here, we have strategically synthesized stable gold (AuNPs(Tyr), AuNPs(Trp)) and silver (AgNPs(Tyr)) nanoparticles which are surface functionalized with either tyrosine or tryptophan residues and have examined their potential to inhibit amyloid aggregation of insulin. Inhibition of both spontaneous and seed-induced aggregation of insulin was observed in the presence of AuNPs(Tyr), AgNPs(Tyr), and AuNPs(Trp) nanoparticles. These nanoparticles also triggered the disassembly of insulin amyloid fibrils. Surface functionalization of amino acids appears to be important for the inhibition effect since isolated tryptophan and tyrosine molecules did not prevent insulin aggregation. Bioinformatics analysis predicts involvement of tyrosine in H-bonding interactions mediated by its C=O, -NH2, and aromatic moiety. These results offer significant opportunities for developing nanoparticle-based therapeutics against diseases related to protein aggregation.

[Effect of space flight on the Kosmos-1129 biosatellite on enzyme activity of the rat liver].

PubMed

Nemeth, S; Tigranian, R A

1983-01-01

After the 18.5 day Cosmos-1129 flight the activity of 7 glucocorticoid-stimulated enzymes of the rat liver was measured. Immediately postflight the activity of tyrosine aminotransferase, tryptophan pyrolase and serine dehydrogenase increased. These enzymes rapidly (within several hours) react to increased glucocorticoids. The activity of aspartate and alanine aminotransferases also increased. These enzymes require many days of a continuous effect of glucocorticoids. The glycogen concentration in the rat liver also grew. At R + 6 the activity of tryptophan pyrolase and serine dehydrogenase decreased and that of the other enzymes returned to normal. The immobilization stress applied postflight led to an increased activity of tyrosine aminotransferase and tryptophan pyrolase. This study gives evidence that after space flight rats are in an acute stress state, evidently, produced by the biosatellite recovery.

Association of amino acids embedded in helium droplets detected by mass spectrometry

NASA Astrophysics Data System (ADS)

Lalanne, Matthieu R.; Achazi, Georg; Reichwald, Sebastian; Lindinger, Albrecht

2015-12-01

Amino acids were embedded in helium droplets. The electron impact ionization allows for detecting positively charged glycine, valine, histidine, tryptophan and their principal fragments. Monomers and polymers with up to four amino acids are reported. Heterodimers of tryptophan and valine or histidine are observed as well as heterodimers of included fragments. The ability of these associations of molecules to form complexes with water is examined.

Direct asymmetric aldol reactions between aldehydes and ketones catalyzed by L-tryptophan in the presence of water.

PubMed

Jiang, Zhaoqin; Yang, Hui; Han, Xiao; Luo, Jie; Wong, Ming Wah; Lu, Yixin

2010-03-21

Primary amino acids and their derivatives were investigated as catalysts for the direct asymmetric aldol reactions between ketones and aldehydes in the presence of water, and L-tryptophan was shown to be the best catalyst. Solvent effects, substrate scope and the influence of water on the reactions were investigated. Quantum chemical calculations were performed to understand the origin of the observed stereoselectivity.

Comprehensive spectroscopic studies on the interaction of biomolecules with surfactant detached multi-walled carbon nanotubes.

PubMed

Sekar, Gajalakshmi; Mukherjee, Amitava; Chandrasekaran, Natarajan

2015-04-01

This paper investigates the interaction of ten diverse biomolecules with surfactant detached Multi-Walled Carbon Nanotubes (MWCNTs) using multiple spectroscopic methods. Declining fluorescence intensity of biomolecules in combination with the hyperchromic effect in UV-Visible spectra confirmed the existence of the ground state complex formation. Quenching mechanism remains static and non-fluorescent. 3D spectral data of biomolecules suggested the possibilities of disturbances to the aromatic microenvironment of tryptophan and tyrosine residues arising out of CNTs interaction. Amide band Shifts corresponding to the secondary structure of biomolecules were observed in the of FTIR and FT-Raman spectra. In addition, there exists an increased Raman intensity of tryptophan residues of biomolecules upon interaction with CNTs. Hence, the binding of the aromatic structures of CNTs with the aromatic amino acid residues, in a particular, tryptophan was evidenced. Far UV Circular spectra have showed the loss of alpha-helical contents in biomolecules upon interaction with CNTs. Near UV CD spectra confirmed the alterations in the tryptophan positions of the peptide backbone. Hence, our results have demonstrated that the interaction of biomolecules with OH-MWCNTs would involve binding cum structural changes and alteration to their aromatic micro-environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Standardization of formulations for the acute amino acid depletion and loading tests.

PubMed

Badawy, Abdulla A-B; Dougherty, Donald M

2015-04-01

The acute tryptophan depletion and loading and the acute tyrosine plus phenylalanine depletion tests are powerful tools for studying the roles of cerebral monoamines in behaviour and symptoms related to various disorders. The tests use either amino acid mixtures or proteins. Current amino acid mixtures lack specificity in humans, but not in rodents, because of the faster disposal of branched-chain amino acids (BCAAs) by the latter. The high content of BCAA (30-60%) is responsible for the poor specificity in humans and we recommend, in a 50g dose, a control formulation with a lowered BCAA content (18%) as a common control for the above tests. With protein-based formulations, α-lactalbumin is specific for acute tryptophan loading, whereas gelatine is only partially effective for acute tryptophan depletion. We recommend the use of the whey protein fraction glycomacropeptide as an alternative protein. Its BCAA content is ideal for specificity and the absence of tryptophan, tyrosine and phenylalanine render it suitable as a template for seven formulations (separate and combined depletion or loading and a truly balanced control). We invite the research community to participate in standardization of the depletion and loading methodologies by using our recommended amino acid formulation and developing those based on glycomacropeptide. © The Author(s) 2015.

Regulation of Staphylococcal Penicillinase Synthesis

PubMed Central

Imsande, John; Zyskind, Judith W.; Mile, Imre

1972-01-01

5-Methyl tryptophan was found to be an efficient inducer of penicillinase synthesis in Staphylococcus aureus. Addition of actinomycin D or tryptophan to the culture medium shuts off the 5-methyl tryptophan-induced synthesis of penicillinase with an apparent half-life of approximately 1 to 2 min, respectively. Hence, in the induction of penicillinase synthesis, 5-methyl tryptophan seems to function as a structural analogue of penicillin rather than by becoming incorporated in proteins and thereby creating faulty penicillinase repressor or antirepressor. This conclusion is supported by similarities in the structures of the two compounds as revealed by solid atomic models. The fact that S. aureus exposed to 14C-penicillin in the absence of protein synthesis failed to synthesize penicillinase at an increased level when cell growth was resumed strongly suggests that a protein involved in the regulation of penicillinase synthesis must be synthesized in the presence of the penicillinase inducer. In turn, this observation suggests that the penicillinase inducer promotes penicillinase synthesis by directing the penicillinase regulatory protein (i.e., the penicillinase antirepressor) to acquire a different conformation when it is synthesized in the presence of the penicillinase inducer. A working model for the regulation of penicillinase synthesis based on these and other data has been constructed and is presented. Images PMID:4333374

Neopterin formation and tryptophan degradation by a human myelomonocytic cell line (THP-1) upon cytokine treatment.

PubMed

Werner-Felmayer, G; Werner, E R; Fuchs, D; Hausen, A; Reibnegger, G; Wachter, H

1990-05-15

Determination of neopterin [D-erythro-6-(1',2',3'-trihydroxypropyl)pterin] in body fluids is a powerful diagnostic tool in a variety of diseases in which activation of cellular immune mechanisms is involved, such as certain malignancies, allograft rejection, and autoimmune and infectious diseases. In vitro, neopterin is released into the supernatant by peripheral blood-derived monocytes/macrophages upon stimulation with gamma-interferon. In parallel, cleavage of tryptophan by indoleamine 2,3-dioxygenase is induced. We report here that the human myelomonocytic cell line THP-1 forms neopterin and degrades tryptophan upon treatment with gamma-interferon. Like in macrophages alpha-interferon and beta-interferon induce these pathways only to a much smaller degree. The action of interferons is enhanced by cotreatment with tumor necrosis factor alpha, lipopolysaccharide, or dexamethasone. gamma-Interferon-induced neopterin formation and indoleamine 2,3-dioxygenase activity are increased by raising extracellular tryptophan concentrations. The pattern of intracellularly formed pteridines upon stimulation with gamma-interferon shows the unique characteristics of human monocytes/macrophages. Neopterin, monapterin, and biopterin are produced in a 50:2:1 ratio. Thus, the THP-1 cell line provides a permanent, easily accessible in vitro system for studying the induction and mechanism of neopterin formation.

Deficiency in methionine, tryptophan, isoleucine, or choline induces apoptosis in cultured cells.

PubMed

Yen, Chi-Liang E; Mar, Mei-Heng; Craciunescu, Corneliu N; Edwards, Lloyd J; Zeisel, Steven H

2002-07-01

Cells in culture die by apoptosis when deprived of the essential nutrient choline. We now report that cells (both proliferating PC12 cells and postmitotic neurons isolated from fetal rat brains) undergo apoptosis when deprived of other individual essential nutrients (methionine, tryptophan or isoleucine). In PC12 cells, deficiencies of each nutrient independently led to ceramide accumulation and to caspase activation, both recognized signals of several apoptotic pathways. A similar profile of caspases was activated in PC12 cells deprived of choline, methionine, tryptophan or isoleucine. More than one caspase was involved and these caspases appeared to transmit parallel signals for apoptosis induction because only broad-spectrum caspase inhibitors, but not inhibitors for specific individual caspases inhibited apoptosis in choline- or methionine-deprived cells. The induction of these caspase-dependent apoptosis pathways likely did not involve the same upstream signals. Choline deficiency perturbed choline metabolism but did not affect protein synthesis, whereas amino acid deficiencies inhibited protein synthesis but did not perturb choline metabolism. In addition, a subclone of PC12 cells that was resistant to choline deficiency-induced apoptosis was not resistant to tryptophan deficiency-induced apoptosis. These observations suggest that deficiency of each studied nutrient activates different pathways for signaling apoptosis that ultimately converge on a common execution pathway.

Correlation of tryptophan fluorescence intensity decay parameters with sup 1 H NMR-determined rotamer conformations: (tryptophan sup 2 )oxytocin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, J.B.A.; Schwartz, G.P.; Laws, W.R.

1992-02-18

While the fluorescence decay kinetics of tyrosine model compounds can be explained in terms of heterogeneity derived from the three ground-state {chi}{sup 1} rotamers, a similar correlation has yet to be directly observed for a tryptophan residue. In addition, the asymmetric indole ring might also lead to heterogeneity from {chi}{sup 2} rotations. In this paper, the time-resolved and steady-state fluorescence properties of (tryptophan{sup 2})oxytocin at pH 3 are presented and compared with {sup 1}H NMR results. According to the unrestricted analyses of individual fluorescence decay curves taken as a function of emission wavelength-independent decay constants, only three exponential terms aremore » required. In addition, the preexponential weighting factors (amplitudes) have the same relative relationship (weights) as the {sup 1}H NMR-determined {chi}{sup 1} rotamer populations of the indole side chain. {sup 15}N was used in heteronuclear coupling experiments to confirm the rotamer assignments. Inclusion of a linked function restricting the decay amplitudes to the {chi}{sup 1} rotamer populations in the individual decay curve analyses and in the global analysis confirms this correlation. According to qualitative nuclear Overhauser data, there are two {chi}{sup 2} populations.« less

Cacao extracts suppress tryptophan degradation of mitogen-stimulated peripheral blood mononuclear cells.

PubMed

Jenny, M; Santer, E; Klein, A; Ledochowski, M; Schennach, H; Ueberall, F; Fuchs, D

2009-03-18

The fruits of Theobroma cacao L. (Sterculiaceae) have been used as food and a remedy for more than 4000 years. Today, about 100 therapeutic applications of cacao are described involving the gastrointestinal, nervous, cardiovascular and immune systems. Pro-inflammatory cytokine interferon-gamma and related biochemical pathways like tryptophan degradation by indoleamine 2,3-dioxygenase and neopterin formation are closely associated with the pathogenesis of such disorders. To determine the anti-inflammatory effect of cacao extracts on interferon-gamma and biochemical consequences in immunocompetent cells. Effects of aqueous or ethanolic extracts of cacao were examined on mitogen-induced human peripheral blood mononuclear cells (PBMC) of healthy donors and on lipopolysaccharide-stimulated myelomonocytic THP-1 cells. Antioxidant activity of extracts was determined by oxygen radical absorption capacity (ORAC) assay. In mitogen-stimulated PBMC, enhanced degradation of tryptophan, formation of neopterin and interferon-gamma were almost completely suppressed by the cacao extracts at doses of > or = 5 microg/mL. Cacao extracts had no effect on tryptophan degradation in lipopolysaccharide-stimulated THP-1 cells. There is a significant suppressive effect of cacao extracts on pro-inflammatory pathways in activated T-cells. Particularly the influence on indoleamine 2,3-dioxygenase could relate to some of the beneficial health effects ascribed to cacao.

Simultaneous determination of plasma creatinine, uric acid, kynurenine and tryptophan by high-performance liquid chromatography: method validation and in application to the assessment of renal function.

PubMed

Zhao, Jianxing

2015-03-01

A high-performance liquid chromatography with ultraviolet detection method has been developed for the simultaneous determination of a set of reliable markers of renal function, including creatinine, uric acid, kynurenine and tryptophan in plasma. Separation was achieved by an Agilent HC-C18 (2) analytical column. Gradient elution and programmed wavelength detection allowed the method to be used to analyze these compounds by just one injection. The total run time was 25 min with all peaks of interest being eluted within 13 min. Good linear responses were found with correlation coefficient >0.999 for all analytes within the concentration range of the relevant levels. The recovery was: creatinine, 101 ± 1%; uric acid, 94.9 ± 3.7%; kynurenine, 100 ± 2%; and tryptophan, 92.6 ± 2.9%. Coefficients of variation within-run and between-run of all analytes were ≤2.4%. The limit of detection of the method was: creatinine, 0.1 µmol/L; uric acid, 0.05 µmol/L; kynurenine, 0.02 µmol/L; and tryptophan, 1 µmol/L. The developed method could be employed as a useful tool for the detection of chronic kidney disease, even at an early stage. Copyright © 2014 John Wiley & Sons, Ltd.

19F NMR studies provide insights into lipid membrane interactions of listeriolysin O, a pore forming toxin from Listeria monocytogenes.

PubMed

Kozorog, Mirijam; Sani, Marc-Antoine; Lenarčič Živković, Martina; Ilc, Gregor; Hodnik, Vesna; Separovic, Frances; Plavec, Janez; Anderluh, Gregor

2018-05-02

Listeria monocytogenes is a mammalian pathogen that causes gastroenteritis, miscarriages and infections of the central nervous system in immunocompromised individuals. Its main virulence factor is listeriolysin O (LLO), a pore-forming cholesterol-dependent cytolysin (CDC), which enables bacterial escape from the phagolysosome and contributes to bacterial pathogenicity. Details of cholesterol (Chol) recognition and membrane binding mechanisms by LLO are still not known. Here we used 19 F-NMR spectroscopy in order to assess LLO-Chol interactions in solution and in a Chol-rich membrane environment. LLO has six tryptophan residues located in the region of the molecule that is first in contact with lipid membranes. 19 F-LLO, which contained 5-fluoro-tryptophans, was prepared by using isotopic labelling in an E. coli expression system. Signals in the 19 F-NMR spectrum of 19 F-LLO were unambiguously assigned by using a series of single Trp → Phe point mutations. The results employing various cholesterol preparations in solution indicate that tryptophan residues are not directly involved in Chol binding in solution. However, significant chemical shift changes were observed upon LLO binding to Chol-rich membranes, highlighting the role of tryptophan residues in membrane interactions (W512) and oligomerisation (W189 and W489).

Caspase recruitment domain 9, microbiota, and tryptophan metabolism: dangerous liaisons in inflammatory bowel diseases.

PubMed

Lamas, Bruno; Richard, Mathias L; Sokol, Harry

2017-07-01

Inflammatory bowel diseases (IBDs) develop as a result of a combination of genetic predisposition, dysbiosis of the gut microbiota, and environmental influences. Here, we describe an example of how caspase recruitment domain 9 (CARD9), one of the numerous IBD susceptibility genes, participate to colitis susceptibility by shaping gut microbiota to produce tryptophan metabolites. Recent study showed that CARD9 mice are more susceptible to colitis as a result of impaired interleukin 22 signaling pathway. Furthermore, aryl hydrocarbon receptor (AhR) ligands from tryptophan metabolism by the gut microbiota participate to intestinal homeostasis by inducing production of interleukin 22 by intestinal immune cells. These data suggest an interaction between CARD9 and the ability of gut microbiota to produce AhR ligands. The microbiota from CARD9 mice fails to metabolize tryptophan leading to defective AhR activation which contributes to the susceptibility of mice to colitis by decreased interleukin 22 production. These effects were abrogated in the presence of AhR agonist. Reduced production of AhR ligands is also observed in the microbiota from individuals with IBD, particularly in those with CARD9 risk alleles associated with IBD. Correcting impaired microbiota functions, such as ability to produce AhR ligands, is an attractive strategy in IBD.

Arabidopsis Phosphoglycerate Dehydrogenase1 of the Phosphoserine Pathway Is Essential for Development and Required for Ammonium Assimilation and Tryptophan Biosynthesis[C][W][OPEN

PubMed Central

Benstein, Ruben Maximilian; Ludewig, Katja; Wulfert, Sabine; Wittek, Sebastian; Gigolashvili, Tamara; Frerigmann, Henning; Gierth, Markus; Flügge, Ulf-Ingo; Krueger, Stephan

2013-01-01

In plants, two independent serine biosynthetic pathways, the photorespiratory and glycolytic phosphoserine (PS) pathways, have been postulated. Although the photorespiratory pathway is well characterized, little information is available on the function of the PS pathway in plants. Here, we present a detailed characterization of phosphoglycerate dehydrogenases (PGDHs) as components of the PS pathway in Arabidopsis thaliana. All PGDHs localize to plastids and possess similar kinetic properties, but they differ with respect to their sensitivity to serine feedback inhibition. Furthermore, analysis of pgdh1 and phosphoserine phosphatase mutants revealed an embryo-lethal phenotype and PGDH1-silenced lines were inhibited in growth. Metabolic analyses of PGDH1-silenced lines grown under ambient and high CO2 conditions indicate a direct link between PS biosynthesis and ammonium assimilation. In addition, we obtained several lines of evidence for an interconnection between PS and tryptophan biosynthesis, because the expression of PGDH1 and PHOSPHOSERINE AMINOTRANSFERASE1 is regulated by MYB51 and MYB34, two activators of tryptophan biosynthesis. Moreover, the concentration of tryptophan-derived glucosinolates and auxin were reduced in PGDH1-silenced plants. In essence, our results provide evidence for a vital function of PS biosynthesis for plant development and metabolism. PMID:24368794

Opposing Biological Functions of Tryptophan Catabolizing Enzymes During Intracellular Infection

PubMed Central

Divanovic, Senad; Sawtell, Nancy M.; Trompette, Aurelien; Warning, Jamie I.; Dias, Alexandra; Cooper, Andrea M.; Yap, George S.; Arditi, Moshe; Shimada, Kenichi; DuHadaway, James B.; Prendergast, George C.; Basaraba, Randall J.; Mellor, Andrew L.; Munn, David H.; Aliberti, Julio

2012-01-01

Recent studies have underscored physiological and pathophysiological roles for the tryptophan-degrading enzyme indolamine 2,3-dioxygenase (IDO) in immune counterregulation. However, IDO was first recognized as an antimicrobial effector, restricting tryptophan availability to Toxoplasma gondii and other pathogens in vitro. The biological relevance of these findings came under question when infectious phenotypes were not forthcoming in IDO-deficient mice. The recent discovery of an IDO homolog, IDO-2, suggested that the issue deserved reexamination. IDO inhibition during murine toxoplasmosis led to 100% mortality, with increased parasite burdens and no evident effects on the immune response. Similar studies revealed a counterregulatory role for IDO during leishmaniasis (restraining effector immune responses and parasite clearance), and no evident role for IDO in herpes simplex virus type 1 (HSV-1) infection. Thus, IDO plays biologically important roles in the host response to diverse intracellular infections, but the dominant nature of this role—antimicrobial or immunoregulatory—is pathogen-specific. PMID:21990421

Enzyme-catalyzed Michael addition for the synthesis of warfarin and its determination via fluorescence quenching of L-tryptophan

NASA Astrophysics Data System (ADS)

Yuan, Yusheng; Yang, Liu; Liu, Shaopu; Yang, Jidong; Zhang, Hui; Yan, Jingjing; Hu, Xiaoli

2017-04-01

A sensitive fluorescence sensor for warfarin was proposed via quenching the fluorescence of L-tryptophan due to the interaction between warfarin and L-tryptophan. Warfarin, as one of the most effective anticoagulants, was designed and synthesized via lipase from porcine pancreas (PPL) as a biocatalyst to catalyze the Michael addition of 4-hydroxycoumarin to α, β-unsaturated enones in organic medium in the presence of water. Furthermore, the spectrofluorometry was used to detect the concentration of warfarin with a linear range and detection limit (3σ/k) of 0.04-12.0 μmol L- 1 (R2 = 0.994) and 0.01 μmol L- 1, respectively. Herein, this was the first application of bio-catalytic synthesis and fluorescence for the determination of warfarin. The proposed method was applied to determine warfarin of the drug in tablets with satisfactory results.

Density functional theory (DFT) study of a new novel bionanosensor hybrid; tryptophan/Pd doped single walled carbon nanotube

NASA Astrophysics Data System (ADS)

Yoosefian, Mehdi; Etminan, Nazanin

2016-07-01

In order to explore a new novel L-amino acid/transition metal doped single walled carbon nanotube based biosensor, density functional theory calculations were studied. These hybrid structures of organic-inorganic nanobiosensors are able to detect the smallest amino acid building block of proteins. The configurations of amine and carbonyl group coordination of tryptophan aromatic amino acid adsorbed on Pd/doped single walled carbon nanotube were compared. The frontier molecular orbital theory, quantum theory atom in molecule and natural bond orbital analysis were performed. The molecular electrostatic potential and the electron density surfaces were constructed. The calculations indicated that the Pd/SWCNT was sensitive to tryptophan suggesting the importance of interaction with biological molecule and potential detecting application. The proposed nanobiosensor represents a highly sensitive detection of protein at ultra-low concentration in diagnosis applications.

L-Tryptophan on Cu(111): engineering a molecular labyrinth driven by indole groups

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yitamben, E. N.; Clayborne, A.; Darling, Seth B.

2015-05-21

The present article investigates the adsorption and molecular orientation of L-Tryptophan, which is both an essential amino acid important for protein synthesis and of particular interest for the development of chiral molecular electronics and biocompatible processes and devices, on Cu(111) using scanning tunneling microscopy and spectroscopy at 55 K and at room temperature. The arrangement of chemisorbed L-Tryptophan on the copper surface varies with both temperature and surface coverage. At low coverage, small clusters form on the surface irrespective of temperature, while at high coverage an ordered chain structure emerges at room temperature, and a tightly packed structure forms amore » molecular labyrinth at low temperature. The dominating superstructure of the adsorbates arises from intermolecular hydrogen bonding, and pi-bonding interactions between the indole groups of neighboring molecules and the Cu surface.« less

Archetypal tryptophan-rich antimicrobial peptides: properties and applications.

PubMed

Shagaghi, Nadin; Palombo, Enzo A; Clayton, Andrew H A; Bhave, Mrinal

2016-02-01

Drug-resistant microorganisms ('superbugs') present a serious challenge to the success of antimicrobial treatments. Subsequently, there is a crucial need for novel bio-control agents. Many antimicrobial peptides (AMPs) show a broad-spectrum activity against bacteria, fungi or viruses and are strong candidates to complement or substitute current antimicrobial agents. Some AMPs are also effective against protozoa or cancer cells. The tryptophan (Trp)-rich peptides (TRPs) are a subset of AMPs that display potent antimicrobial activity, credited to the unique biochemical properties of tryptophan that allow it to insert into biological membranes. Further, many Trp-rich AMPs cross bacterial membranes without compromising their integrity and act intracellularly, suggesting interactions with nucleic acids and enzymes. In this work, we overview some archetypal TRPs derived from natural sources, i.e., indolicidin, tritrpticin and lactoferricin, summarising their biochemical properties, structures, antimicrobial activities, mechanistic studies and potential applications.

Melatonin and its precursors scavenge nitric oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noda, Y.; Mori, A.; Liburdy, R.

Nitric oxide (NO) scavenging activity of melatonin, N-acetyl-5-hydroxytryptamine, serotonin, 5-hydroxytryptophan and L-tryptophan was examined by the Griess reaction using flow injection analysis. 1-Hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene(NOC-7) was used as NO generator. The Griess reagent stoichiometrically reacts with NO2-, which was converted by a cadmium-copper reduction column from the stable end products of NO oxidation. Except for tryptophan, all the compounds examined scavenged NO in a dose-dependent manner. Melatonin, which has a methoxy group in the 5-position and an acetyl side chain, exhibited the most potent scavenging activity among the compounds tested. Serotonin, N-acetyl-5-hydroxytryptamine, and 5-hydroxytryptophan, respectively, showed moderate scavenging activity compared to melatonin.more » Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.« less

Effects of biogenic aldehydes and aldehyde dehydrogenase inhibitors on rat brain tryptophan hydroxylase activity in vitro.

PubMed

Nilsson, G E; Tottmar, O

1987-04-21

The effect of indole-3-acetaldehyde, 5-hydroxyindole-3-acetaldehyde, disulfiram, diethyldithiocarbamate, coprine, and 1-amino-cyclopropanol on tryptophan hydroxylase activity was studied in vitro using high performance liquid chromatography with electro-chemical detection. With the analytical method developed, 5-hydroxytryptophan, serotonin, and 5-hydroxyindole-3-acetic acid could be measured simultaneously. Indole-3-acetaldehyde (12-1200 microM) was found to cause a 6-33% inhibition of the enzyme. Dependent upon the nature of the sulfhydryl- or reducing-agent (dithiotreitol, glutathione, or ascorbate) present in the incubates, the degree of inhibition by disulfiram varied, probably due to the formation of various mixed disulfides. Also the presence of diethyldithiocarbamate (160-1600 microM) was found to inhibit tryptophan hydroxylase (28-91%), while 5-hydroxyindole-3-acetaldehyde, coprine, or 1-aminocyclopropanol appeared to have no effect on the enzyme activity.

Development of a composite chiral stationary phase from BSA and β-cyclodextrin-bonded silica.

PubMed

Yao, Bixia; Yang, Xinmei; Guo, Lizhen; Kang, Shanshan; Weng, Wen

2014-01-01

A composite chiral stationary phase (CSP) derived from bovine serum albumin (BSA) and β-cyclodextrin (CD)-bonded silica was prepared. 2,4,6-Trichloro-1,3,5-triazine was used as a cross-linker. The obtained CSP was applied to the enantioseparation of tryptophan, hydrobenzoin, phenylalanine and mandelic acid. The influences of eluent pH value, organic modifier and column temperature on the retention and enantioseparation were discussed. Tryptophan and hydrobenzoin achieved excellent resolution on the composite CSP. For tryptophan, the highest selectivity, 2.79, was achieved with 1% of methanol at pH 8.0. For hydrobenzoin, the selectivity could reach 1.42. The chromatographic results were compared with that on β-CD-bonded or BSA-immobilized CSP. © The Author [2014]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A novel experimental system of high stability and lifetime for the laser-desorption of biomolecules.

PubMed

Taherkhani, Mehran; Riese, Mikko; BenYezzar, Mohammed; Müller-Dethlefs, Klaus

2010-06-01

A novel laser desorption system, with improved signal stability and extraordinary long lifetime, is presented for the study of jet-cooled biomolecules in the gas phase using vibrationally resolved photoionization spectroscopy. As a test substance tryptophane is used to characterize this desorption source. A usable lifetime of above 1 month (for a laser desorption repetition rate of 20 Hz) has been observed by optimizing the pellets (graphite/tryptophane, 3 mm diameter and 6 mm length) from which the substance is laser-desorbed. Additionally, the stability and signal-to-noise ratio has been improved by averaging the signal over the entire sample pellet by synchronizing the data acquisition with the rotation of the sample rod. The results demonstrate how a combination of the above helps to produce stable and conclusive spectra of tryptophane using one-color and two-color resonant two-photon ionization studies.

Conserved Tryptophan Motifs in the Large Tegument Protein pUL36 Are Required for Efficient Secondary Envelopment of Herpes Simplex Virus Capsids

PubMed Central

Ivanova, Lyudmila; Buch, Anna; Döhner, Katinka; Pohlmann, Anja; Binz, Anne; Prank, Ute; Sandbaumhüter, Malte

2016-01-01

ABSTRACT Herpes simplex virus (HSV) replicates in the skin and mucous membranes, and initiates lytic or latent infections in sensory neurons. Assembly of progeny virions depends on the essential large tegument protein pUL36 of 3,164 amino acid residues that links the capsids to the tegument proteins pUL37 and VP16. Of the 32 tryptophans of HSV-1-pUL36, the tryptophan-acidic motifs 1766WD1767 and 1862WE1863 are conserved in all HSV-1 and HSV-2 isolates. Here, we characterized the role of these motifs in the HSV life cycle since the rare tryptophans often have unique roles in protein function due to their large hydrophobic surface. The infectivity of the mutants HSV-1(17+)Lox-pUL36-WD/AA-WE/AA and HSV-1(17+)Lox-CheVP26-pUL36-WD/AA-WE/AA, in which the capsid has been tagged with the fluorescent protein Cherry, was significantly reduced. Quantitative electron microscopy shows that there were a larger number of cytosolic capsids and fewer enveloped virions compared to their respective parental strains, indicating a severe impairment in secondary capsid envelopment. The capsids of the mutant viruses accumulated in the perinuclear region around the microtubule-organizing center and were not dispersed to the cell periphery but still acquired the inner tegument proteins pUL36 and pUL37. Furthermore, cytoplasmic capsids colocalized with tegument protein VP16 and, to some extent, with tegument protein VP22 but not with the envelope glycoprotein gD. These results indicate that the unique conserved tryptophan-acidic motifs in the central region of pUL36 are required for efficient targeting of progeny capsids to the membranes of secondary capsid envelopment and for efficient virion assembly. IMPORTANCE Herpesvirus infections give rise to severe animal and human diseases, especially in young, immunocompromised, and elderly individuals. The structural hallmark of herpesvirus virions is the tegument, which contains evolutionarily conserved proteins that are essential for several stages of the herpesvirus life cycle. Here we characterized two conserved tryptophan-acidic motifs in the central region of the large tegument protein pUL36 of herpes simplex virus. When we mutated these motifs, secondary envelopment of cytosolic capsids and the production of infectious particles were severely impaired. Our data suggest that pUL36 and its homologs in other herpesviruses, and in particular such tryptophan-acidic motifs, could provide attractive targets for the development of novel drugs to prevent herpesvirus assembly and spread. PMID:27009950

Altered tryptophan catabolite concentrations in major depressive disorder and associated changes in hippocampal subfield volumes.

PubMed

Doolin, Kelly; Allers, Kelly A; Pleiner, Sina; Liesener, Andre; Farrell, Chloe; Tozzi, Leonardo; O'Hanlon, Erik; Roddy, Darren; Frodl, Thomas; Harkin, Andrew; O'Keane, Veronica

2018-05-19

Tryptophan depletion is a well-replicated biological finding in Major Depressive Disorder (MDD). The kynurenine pathway (KP) and its rate-limiting tryptophan degrading enzyme, indolamine 2,3 dioxygenase (IDO), have been implicated in the pathogenesis of depression. IDO expression is driven by inflammatory cytokines, providing a putative link between inflammation and neuropathology. This study examined circulating concentrations of C-reactive protein (CRP), plasma tryptophan, kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QUIN) and whole blood mRNA expression of IDO in patients with major depressive disorder (MDD) compared with healthy controls (HC). A diagnosis of major depression was made according to DSM-IV. Depression severity was assessed using the Hamilton depression (HAM-D) rating scale. 74 MDD patients, 39 with a first presentation of MDD (fpMDD) and 35 with chronic or recurrent episodes (rMDD), and 37 HC were recruited to the study. Whole blood and plasma samples were collected. Expression of markers in whole blood were measured by PCR, circulating CRP by ELISA and KP metabolites by LC-MS/MS. Hippocampal cornu ammonis (CA) and subiculum volumes were determined by MRI and calculated using FreeSurfer. Tryptophan concentrations were significantly reduced in MDD compared to HC. There was a positive correlation between QUIN and both CRP concentrations and whole blood IDO1 in MDD. KYNA concentrations were reduced in MDD patients presenting with a first episode (fpMDD) compared to those presenting with recurrent depression (rMDD) and HC. By contrast QUIN concentrations were elevated in rMDD compared to fpMDD and HC. KYNA/QUIN was reduced in MDD and rMDD but not fpMDD compared to HC. Hippocampal subfield volumes were smaller in MDD patients than HC for CA1 (left only), CA2/3 (left and right) and CA4 (right only). CRP and CA1 volumes were negatively correlated bilaterally in MDD patients. KYNA and subiculum volume were positively correlated bilaterally. This study found evidence of KP metabolism imbalance in MDD patients in addition to tryptophan reduction and mild immune activation. Relationships between CRP and KYNA with some hippocampal subfield volumes in MDD patients suggest that this inflammatory signature may be associated with reduced hippocampal subfield volumes in depression. Copyright © 2018 Elsevier Ltd. All rights reserved.

An exploration of the associations of pregnancy and perinatal features with cytokines and tryptophan/kynurenine metabolism in children with attention-deficit hyperactivity disorder (ADHD).

PubMed

Oades, Robert D

2011-12-01

Intra-individual variability of the characteristics of children with attention-deficit hyperactivity (ADHD) may reflect compromised glial energy supply in the synapse. We reported recently that while serum levels of a glial marker, the cytokine S100B, were not seriously altered, levels of other cytokines and tryptophan metabolites were related to symptoms, attention and variability. Here, we explore with a regression analysis whether levels of these substances were associated with features of the index pregnancy of potential aetiological significance. Serum was taken from 35 children with DSM-IV ADHD (14 on medication) and 21 typically developing controls to measure 8 cytokines (S100B, IL-2, IL-6, IL-10, IL-13, IL-16, TNF-α and IFN-γ) and 5 metabolites (Tryptophan, Kynurenine, Kynurenate [KA], 3-hydroxy-kynurenine [3HK] and 5-hydroxyindole acetic acid [5-HIAA]). The mothers received a 124-item questionnaire on features surrounding the pregnancy. (1) For children with ADHD, a shorter pregnancy and smaller birth weight were associated statistically with increased 3HK and IFN-γ and for obstetric problems with decreased TNF-α levels. (2) Maternal smoking related to decreasing kynurenine and increasing 3HK and S100B levels in ADHD children. Paternal smoking was associated with increased tryptophan in the controls and increased IL-6 levels in ADHD children. (3) The taking of supplements often related to decreasing TNF-α, increasing IL-10 and lower 5-HIAA levels in the ADHD children. Less 5-HIAA but more tryptophan was associated with earlier and later life events, respectively. (4) Increased IL-16 and 5-HIAA levels in the ADHD group related to reports of poorer infant health. Unexpectedly, more child care (seafood and time together) in ADHD than healthy families was implicated by lower tryptophan levels and an altered balance of pro-inflammatory cytokines. Across measures control families generally showed either non-significant associations or the opposite to those of the ADHD group. In ADHD children more than controls, the balance of potentially toxic or protective kynurenine metabolites and of pro- over anti-inflammatory cytokines may reflect the perinatal experience associated with stress, but not with maternal illness.

Improving the quality of infant sleep through the inclusion at supper of cereals enriched with tryptophan, adenosine-5'-phosphate, and uridine-5'-phosphate.

PubMed

Cubero, Javier; Chanclón, Belen; Sánchez, Soledad; Rivero, Montserrat; Rodríguez, Ana Beatriz; Barriga, Carmen

2009-12-01

The present study evaluated whether the administration of cereals enriched with nutrients that are facilitators of sleep could help improve the sleep of infants who had sleep disorders at night time. Thirty infants aged 8-16 months with sleep disorders involving at least three nocturnal waking episodes took part in the study. They were given a night-time 'sleep facilitating cereal' product containing 225 mg tryptophan, 5.3 mg adenosine-5'-P, and 6.3 mg uridine-5'-P per 100 g of product. These cereals were given in a double-blind procedure lasting 5 weeks, with ingestion of the cereal between 18:00 and 06:00. In the control week, the children received a standard cereal (75 mg tryptophan/100 g product without nucleotides) dissolved in a standard formula milk (231.5 mg tryptophan, 2.6 mg adenosine-5'-P, 5 mg uridine-5'-P, per 100 g product). In one experimental week, the children received the night-time sleep facilitating cereal together with the standard formula milk. In another week, they received the sleep facilitating cereal together with a night milk specially formulated to attain the sleep rhythm (480 mg tryptophan, 8.8 mg uridine-5'-P, and 7.6 mg adenosine-5'-P per 100 g product). The three experimental weeks were separated by two wash-out weeks in which the milk and cereal administered was identical in composition to that of the control week. All the infants received a programmed writer actimeter which they wore continually, attached to their ankles, to record their motor activity. The recorded activity was used to calculate information about the time in bed, assumed sleep, actual sleep, sleep efficiency, sleep latency, immobility, and total activity. The infants receiving the enriched cereal during the time of darkness showed improvements in their sleep parameters, regardless of whether the milk they took at night was standard or enriched with tryptophan, adenosine-5'-P, and uridine-5'-P. In summary, the administration of enriched cereals led to an improvement in sleep, regardless of the type of infant milk used. These results support the concept of chrononutrition since they confirm that the sleep/wake rhythm can be influenced by diet.

Biochemical Markers of Possible Immunodepression in Military Training in Harsh Environments

DTIC Science & Technology

2010-03-01

were measured as possible markers of fatigue and immuno- depression. together with nonesterified fatty acids (p[ NEFA |) and total antioxidani...capacity (p[TACl). Changes were observed in plasma free tryptophan {p[FTJ). p[GIn]. p[Lep]. p| NEFA ]. p(TACl but not branched chain amino acids (p[BCAAJ...com- petes with free fatty acids ( NEFA ). Unbound (free) tryptophan (FT) competes with BCAA for the same port of entry into the brain across the blood

Self-assembled nanotubes from single fluorescent amino acid

NASA Astrophysics Data System (ADS)

Babar, Dipak Gorakh; Sarkar, Sabyasachi

2017-04-01

Self-assembly of biomolecules has gained increasing attention as it generates various supramolecular structural assemblies having potential applications principally in biomedical sciences. Here, we show that amino acid like tryptophan or tyrosine readily aggregates as nanotubes via a simple self-assembly process. These were characterized by FTIR, scanning electron microscopy, and by fluorescence microscopy. Nanotubes prepared from tryptophan are having 200 nm inner diameter and those from tyrosine are having the same around 50 nm diameter.

Serotonin Transporter Polymorphism Mediates Vulnerability to Loss of Incentive Motivation Following Acute Tryptophan Depletion

PubMed Central

Roiser, Jonathan P; Blackwell, Andrew D; Cools, Roshan; Clark, Luke; Rubinsztein, David C; Robbins, Trevor W; Sahakian, Barbara J

2007-01-01

The serotonin (5-HT) system is implicated in incentive motivational processes. The present study utilized the acute tryptophan depletion (ATD) procedure to investigate the effect of temporarily lowering 5-HT synthesis on motivation in healthy volunteers, stratifying the results by allelic variation at the serotonin transporter gene (5-HTTLPR). ATD resulted in a robust reduction in plasma tryptophan concentration. Consistent with a previous study, ATD attenuated motivationally speeded action on the Cued-Reinforcement Reaction Time task. The present investigation revealed that this effect was restricted to volunteers of the ss genotype, whereas ll volunteers exhibited intact motivationally speeded action following ATD (treatment × reinforcement probability × genotype interaction: F1,26 = 5.8, p = 0.024). Furthermore, tryptophan availability to the brain was correlated positively with motivationally speeded action following ATD in the ss genotype group (ρ13 = 0.71, p = 0.006), whereas this correlation was negative in the ll genotype group (ρ14 = −0.60, p = 0.023). This is the first study to suggest that allelic variation at the 5-HTTLPR mediates motivational responses to ATD in healthy volunteers. These data indicate that the s allele at the 5-HTTLPR may confer risk for depression via its effect on incentive motivational processing, and highlight the importance of genetic variation in determining individual responses to pharmacological treatments. PMID:16541086

NMDA channel gating is influenced by a tryptophan residue in the M2 domain but calcium permeation is not altered.

PubMed Central

Buck, D P; Howitt, S M; Clements, J D

2000-01-01

N-Methyl-D-aspartate (NMDA) receptors are susceptible to open-channel block by dizolcipine (MK-801), ketamine and Mg(2+) and are permeable to Ca(2+). It is thought that a tryptophan residue in the second membrane-associated domain (M2) may form part of the binding site for open-channel blockers and contribute to Ca(2+) permeability. We tested this hypothesis using recombinant wild-type and mutant NMDA receptors expressed in HEK-293 cells. The tryptophan was mutated to a leucine (W-5L) in both the NMDAR1 and NMDAR2A subunits. MK-801 and ketamine progressively inhibited currents evoked by glutamate, and the rate of inhibition was increased by the W-5L mutation. An increase in open channel probability accounted for the acceleration. Fluctuation analysis of the glutamate-evoked current revealed that the NMDAR1 W-5L mutation increased channel mean open time, providing further evidence for an alteration in gating. However, the equilibrium affinities of Mg(2+) and ketamine were largely unaffected by the W-5L mutation, and Ca(2+) permeability was not decreased. Therefore, the M2 tryptophan residue of the NMDA channel is not involved in Ca(2+) permeation or the binding of open-channel blockers, but plays an important role in channel gating. PMID:11053122

Tryptophan PET Imaging of the Kynurenine Pathway in Patient-Derived Xenograft Models of Glioblastoma.

PubMed

Guastella, Anthony R; Michelhaugh, Sharon K; Klinger, Neil V; Kupsky, William J; Polin, Lisa A; Muzik, Otto; Juhász, Csaba; Mittal, Sandeep

2016-01-01

Increasing evidence demonstrates the immunosuppressive kynurenine pathway's (KP) role in the pathophysiology of human gliomas. To study the KP in vivo, we used the noninvasive molecular imaging tracer α-[(11)C]-methyl-l-tryptophan (AMT). The AMT-positron emission tomography (PET) has shown high uptake in high-grade gliomas and predicted survival in patients with recurrent glioblastoma (GBM). We generated patient-derived xenograft (PDX) models from dissociated cells, or tumor fragments, from 5 patients with GBM. Mice bearing subcutaneous tumors were imaged with AMT-PET, and tumors were analyzed to detect the KP enzymes indoleamine 2,3-dioxygenase (IDO) 1, IDO2, tryptophan 2,3-dioxygenase, kynureninase, and kynurenine 3-monooxygenase. Overall, PET imaging showed robust tumoral AMT uptake in PDX mice with prolonged tracer accumulation over 60 minutes, consistent with AMT trapping seen in humans. Immunostained tumor tissues demonstrated positive detection of multiple KP enzymes. Furthermore, intracranial implantation of GBM cells was performed with imaging at both 9 and 14 days postimplant, with a marked increase in AMT uptake at 14 days and a corresponding high level of tissue immunostaining for KP enzymes. These results indicate that our PDX mouse models recapitulate human GBM, including aberrant tryptophan metabolism, and offer an in vivo system for development of targeted therapeutics for patients with GBM. © The Author(s) 2016.

Heme-containing enzymes and inhibitors for tryptophan metabolism.

PubMed

Yan, Daojing; Lin, Ying-Wu; Tan, Xiangshi

2017-09-20

Iron-containing enzymes such as heme enzymes play crucial roles in biological systems. Three distinct heme-containing dioxygenase enzymes, tryptophan 2,3-dioxygenase (TDO), indoleamine 2,3-dioxygenase 1 (IDO1) and indoleamine 2,3-dioxygenase 2 (IDO2) catalyze the initial and rate-limiting step of l-tryptophan catabolism through the kynurenine pathway in mammals. Overexpression of these enzymes causes depletion of tryptophan and the accumulation of metabolic products, which contributes to tumor immune tolerance and immune dysregulation in a variety of disease pathologies. In the past few decades, IDO1 has garnered the most attention as a therapeutic target with great potential in cancer immunotherapy. Many potential inhibitors of IDO1 have been designed, synthesized and evaluated, among which indoximod (d-1-MT), INCB024360, GDC-0919 (formerly NLG-919), and an IDO1 peptide-based vaccine have advanced to the clinical trial stage. However, recently, the roles of TDO and IDO2 have been elucidated in immune suppression. In this review, the current drug discovery landscape for targeting TDO, IDO1 and IDO2 is highlighted, with particular attention to the recent use of drugs in clinical trials. Moreover, the crystal structures of these enzymes, in complex with inhibitors, and the mechanisms of Trp catabolism in the first step, are summarized to provide information for facilitating the discovery of new enzyme inhibitors.

Systems metabolic engineering of Escherichia coli for production of the antitumor drugs violacein and deoxyviolacein.

PubMed

Rodrigues, André L; Trachtmann, Nathalie; Becker, Judith; Lohanatha, Ananta F; Blotenberg, Jana; Bolten, Christoph J; Korneli, Claudia; de Souza Lima, André O; Porto, Luismar M; Sprenger, Georg A; Wittmann, Christoph

2013-11-01

Violacein and deoxyviolacein are interesting therapeutics against pathogenic bacteria and viruses as well as tumor cells. In the present work, systems-wide metabolic engineering was applied to target Escherichia coli, a widely accepted recombinant host in pharmaceutical biotechnology, for production of these high-value products. The basic producer, E. coli dVio-1, that expressed the vioABCE cluster from Chromobacterium violaceum under control of the inducible araC system, accumulated 180 mg L(-1) of deoxyviolacein. Targeted intracellular metabolite analysis then identified bottlenecks in tryptophan supporting pathways, the major product building block. This was used for comprehensive engineering of serine, chorismate and tryptophan biosynthesis and the non-oxidative pentose-phosphate pathway. The final strain, E. coli dVio-6, accumulated 320 mg L(-1) deoxyviolacein in shake flask cultures. The created chassis of a high-flux tryptophan pathway was complemented by genomic integration of the vioD gene of Janthinobacterium lividum, which enabled exclusive production of violacein. In a fed-batch process, the resulting producer E. coli Vio-4 accumulated 710 mg L(-1) of the desired product. With straightforward broth extraction and subsequent crystallization, violacein could be obtained with 99.8% purity. This demonstrates the potential of E. coli as a platform for production of tryptophan based therapeutics. Copyright © 2013 Elsevier Inc. All rights reserved.

Modification of a single tryptophan residue in human Cu,Zn-superoxide dismutase by peroxynitrite in the presence of bicarbonate.

PubMed

Yamakura, F; Matsumoto, T; Fujimura, T; Taka, H; Murayama, K; Imai, T; Uchida, K

2001-07-09

Human recombinant Cu,Zn-SOD was reacted with peroxynitrite in a reaction mixture containing 150 mM potassium phosphate buffer (pH 7.4) 25 mM sodium bicarbonate, and 0.1 mM diethylenetriamine pentaacetic acid. Disappearance of fluorescence emission at 350 nm, which could be attributed to modification of a single tryptophan residue, was observed in the modified enzyme with a pH optimum of around 8.4. A fluorescence decrease with the same pH optimum was also observed without sodium bicarbonate, but with less efficiency. Amino acid contents of the modified enzyme showed no significant difference in all amino acids except the loss of a single tryptophan residue of the enzyme. The peroxynitrite-modified enzyme showed an increase in optical absorption around 350 nm and 30% reduced enzyme activity based on the copper contents. The modified enzyme showed the same electron paramagnetic resonance spectrum as that of the control enzyme. The modified Cu,Zn-SOD showed a single protein band in sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS--PAGE) and five protein bands in non-denaturing PAGE. From this evidence, we conclude that nitration and/or oxidation of the single tryptophan 32 and partial inactivation of the enzyme activity of Cu,Zn-SOD is caused by a peroxynitrite-carbon dioxide adduct without perturbation of the active site copper integrity.

Structure based mimicking of Phthalic acid esters (PAEs) and inhibition of hACMSD, an important enzyme of the tryptophan kynurenine metabolism pathway.

PubMed

Singh, Neha; Dalal, Vikram; Kumar, Pravindra

2018-03-01

Human α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (hACMSD) is a zinc containing amidohydrolase which is a vital enzyme of the kynurenine pathway in tryptophan metabolism. It prevents the accumulation of quinolinic acid (QA) and helps in the maintenance of basal Trp-niacin ratio. To assess the structure based inhibitory action of PAEs such as DMP, DEP, DBP, DIBP, DEHP and their metabolites, these were docked into the active site cavity of hACMSD. Docking results show that the binding affinities of PAEs lie in the comparable range (-4.9 kca/mol-7.48kcal/mol) with Dipicolinic acid (-6.21kcal/mol), a substrate analogue of hACMSD. PAEs interact with the key residues such as Arg47 and Trp191 and lie within the 4Å vicinity of zinc metal at the active site of hACMSD. Dynamics and stability of the PAEs-hACMSD complexes were determined by performing molecular dynamics simulations using GROMACS 5.14. Binding free energy calculations of the PAEs-hACMSD complexes were estimated by using MMPBSA method. The results emphasize that PAEs can structurally mimic the binding pattern of tryptophan metabolites to hACMSD, which further leads to inhibition of its activity and accumulation of the quinolate in the kynurenine pathway of tryptophan metabolism. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of disordered hemes and dimerization in isolated a-subunits of hemoglobin detected by time-resolved fluorescence spectroscopy in the picosecond range

NASA Astrophysics Data System (ADS)

Gryczynski, Zygmunt; Fronticelli, Clara; Gratton, Enrico; Lubkowski, Jacek; Bucci, Enrico

1994-08-01

Our recent linear dichroism study of transition moment directions for protoporphyrin derivatives [1,2] demonstrate that heme cannot be considered a planar oscillator when it acts as an acceptor of radiationless excitation energy transfer from tryptophan. The linear nature of the heme absorption transition moment implies a strong dependence of the transfer rate factors on the relative angular position of the heme and tryptophan, i.e. on the k2 orientation parameter of the Forster equation. Using the atomic coordinates of human hemoglobin and taking into account the direction of the transition moment of the near UV (300-380 nm) heme absorption band we have estimated the rate of energy transfer from tryptophan to heme in the isolated a chains, which are a single tryptophan protein. It appears that the rate of energy transfer is very sensitive to the orientation of the transition moment of the heme and similarly to myoglobin [3] natural heme disorder significantly reduces the transfer efficiency in isolated a subunits. On this basis we were able to predict very accurately the two lifetimes detectable in the systems, of 32 and 1050 ps respectively, where the amplitude of the longer lifetime is very consistent with the amount of disordered hemes found by La Mar [4,5] for the a subunits of hemoglobin.

Psychiatric side effects and fluctuations in serotonergic parameters in the treatment of chronic hepatitis C infection.

PubMed

Bezemer, G; Van Gool, A R; Fekkes, D; Vrolijk, J M; Hansen, B E; Janssen, H L A; de Knegt, R J

2012-01-01

Treatment of hepatitis C with peginterferon induces psychiatric side effects. These might include changes in serotonergic function. Twenty-two hepatitis C patients were treated with peginterferon. At different time points, psychometric assessment was performed using the profile of mood states. Plasma samples were taken to study serotonergic parameters. Anger and depression increased compared to baseline, starting with anger (from week 3 onwards), followed by depression (from week 7 onwards). Other scores did not show consistent changes. No consistent changes were observed in tryptophan, tryptophan/large neutral amino acids ratio, biopterin and 5-hydroxyindoleacetic acid. The tyrosine/large neutral amino acids ratio, neopterin, phenylalanine/tyrosine ratio, and prolactin concentrations increased compared to baseline. Prolactin levels were associated with the occurrence of depression and anger. Particularly anger and depression increased during treatment. Neither a decrease in tryptophan and tryptophan availability was seen, nor a relationship between these parameters and the development of psychopathology. Therefore, other mechanisms in the induction of psychopathology should be considered. The observed increases in neopterin and phenylalanine/tyrosine ratio are indicative of changes in tetrahydrobiopterin, which is involved in the metabolism of serotonin, noradrenaline and dopamine, and possibly mediating the increase in prolactin. The increase in prolactin levels and its relationship with depression and anger needs further exploration. Copyright © 2012 S. Karger AG, Basel.

An artificial self-sufficient cytochrome P450 directly nitrates fluorinated tryptophan analogs with a different regio-selectivity.

PubMed

Zuo, Ran; Zhang, Yi; Huguet-Tapia, Jose C; Mehta, Mishal; Dedic, Evelina; Bruner, Steven D; Loria, Rosemary; Ding, Yousong

2016-05-01

Aromatic nitration is an immensely important industrial process to produce chemicals for a variety of applications, but it often suffers from multiple unsolved challenges. Enzymes as biocatalysts have been increasingly used for organic chemistry synthesis due to their high selectivity and environmental friendliness, but nitration has benefited minimally from the development of biocatalysis. In this work, we aimed to develop TxtE as practical biocatalysts for aromatic nitration. TxtE is a unique class I cytochrome P450 enzyme that nitrates the indole of l-tryptophan. To develop cost-efficient nitration processes, we fused TxtE with the reductase domains of CYP102A1 (P450BM3) and of P450RhF to create class III self-sufficient biocatalysts. The best engineered fusion protein was comparable with wild type TxtE in terms of nitration performance and other key biochemical properties. To demonstrate the application potential of the fusion enzyme, we nitrated 4-F-dl-tryptophan and 5-F-l-tryptophan in large scale enzymatic reactions. Tandem MS/MS and NMR analyses of isolated products revealed altered nitration sites. To our knowledge, these studies represent the first practice in developing biological nitration approaches and lay a solid basis to the use of TxtE-based biocatalysts for the production of valuable nitroaromatics. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

TRYCAT pathways link peripheral inflammation, nicotine, somatization and depression in the etiology and course of Parkinson's disease.

PubMed

Anderson, George; Maes, Michael

2014-02-01

Increased depression, somatization, gut inflammation and wider peripheral inflammation are all associated with the early stages of Parkinson's disease (PD). Classically such concurrent conditions have been viewed as "comorbidities", driven by high levels of stress in a still poorly understood and treated disorder. Here we review the data on how oxidative and nitrosative stress in association with immuno-inflammatory responses, drives alteration in tryptophan catabolites, including kynurenine, kynurenic acid and quinolinic acid that drive not only the 'comorbidities" of PD but also important processes in the etiology and course of PD per se. The induction of indoleamine 2,3-dioxygenase, leading to the driving of tryptophan into neuroregulatory tryptophan catabolite products and away from serotonin and melatonin production, has significant implications for understanding the role of nicotine, melatonin, and caffeine in regulating PD susceptibility. Tryptophan catabolite pathway activation will also regulate blood-brain barrier permeability, glia and mast cell reactivity as well as wider innate and adaptive immune cell responses, all relevant to the course of PD. As such, the "comorbidities" of PD such as depression, somatization and peripheral inflammatory disorders can all be conceptualized as being an intricate part of the biological underpinnings of both the etiology and course of PD. As a consequence, the data reviewed here has treatment implications; relevant to both the course of PD and in the management of L-DOPA induced dyskinesias.

Protein side chain rotational isomerization: A minimum perturbation mapping study

NASA Astrophysics Data System (ADS)

Haydock, Christopher

1993-05-01

A theory of the rotational isomerization of the indole side chain of tryptophan-47 of variant-3 scorpion neurotoxin is presented. The isomerization potential energy, entropic part of the isomerization free energy, isomer probabilities, transition state theory reaction rates, and indole order parameters are calculated from a minimum perturbation mapping over tryptophan-47 χ1×χ2 torsion space. A new method for calculating the fluorescence anisotropy from molecular dynamics simulations is proposed. The method is based on an expansion that separates transition dipole orientation from chromophore dynamics. The minimum perturbation potential energy map is inverted and applied as a bias potential for a 100 ns umbrella sampling simulation. The entropic part of the isomerization free energy as calculated by minimum perturbation mapping and umbrella sampling are in fairly close agreement. Throughout, the approximation is made that two glutamine and three tyrosine side chains neighboring tryptophan-47 are truncated at the Cβ atom. Comparison with the previous combination thermodynamic perturbation and umbrella sampling study suggests that this truncated neighbor side chain approximation leads to at least a qualitatively correct theory of tryptophan-47 rotational isomerization in the wild type variant-3 scorpion neurotoxin. Analysis of van der Waals interactions in a transition state region indicates that for the simulation of barrier crossing trajectories a linear combination of three specially defined dihedral angles will be superior to a simple side chain dihedral reaction coordinate.

Raman signature of the non-hydrogen-bonded tryptophan side chain in proteins: experimental and ab initio spectra of 3-methylindole in the gas phase

NASA Astrophysics Data System (ADS)

Combs, Amanda; McCann, Kathleen; Autrey, Daniel; Laane, Jaan; Overman, Stacy A.; Thomas, George J.

2005-02-01

3-Methylindole (3MI), which serves as a structural model for the tryptophan side chain in proteins, has been investigated using vapor phase Raman spectroscopy. The vapor phase spectrum of 3MI identifies the Raman signature of the indolyl moiety free of intermolecular interaction and extends previously reported solution Raman studies of 3MI and related tryptophan derivatives. The Raman spectrum of 3MI vapor is also complemented here with newly obtained vapor phase infrared data and ab initio calculations to refine and extend previous vibrational assignments. The present results provide an improved basis for assessing the dependence of the indolyl Raman signature on the local environment of the tryptophan side chain of proteins. The principal conclusions of this work are the following. (i) The vapor phase 3MI molecule exhibits Raman bands at 3506, 1585, 1409, 1349/1341 (Fermi doublet) and 881 cm-1, which differ greatly from their counterparts in the Raman spectrum of 3MI liquid and thus serve as spectral markers of the indolyl ring environment. (ii) The Fermi doublet relative intensity ratio (I1/I2, where I1 and I2 are, respectively, the Raman intensities of the higher and lower wavenumber components of the doublet) is highly sensitive to the state of 3MI condensation, consistent with the previously reported sensitivity of I1/I2 to solvent polarity. The maximum value of the intensity ratio (I1/I2=3.0) is observed for 3MI vapor, while the minimum value (I1/I2=0.43) is observed for 3MI in CHCl3 solution. Implications of the present results for Raman analysis of hydrogen bonding states, hydrophilic interactions and hydrophobic interactions of tryptophan residues in proteins are considered.

Interaction of KMP-11 with Phospholipid Membranes and Its Implications in Leishmaniasis: Effects of Single Tryptophan Mutations and Cholesterol.

PubMed

Sannigrahi, Achinta; Maity, Pabitra; Karmakar, Sanat; Chattopadhyay, Krishnananda

2017-03-02

KMP-11 is a small protein that is believed to control the overall bilayer pressure of the Leishmania parasite. Recent results have suggested that membrane binding and the presence of cholesterol affect the efficacy of Leishmanial infection, in which KMP-11 plays an important role. Nevertheless, there exists no systematic study of membrane interaction with KMP-11 either in the absence or presence of cholesterol. In this article, we investigated the interaction between KMP-11 and phospholipid membranes using an unsaturated (PC 18:1; 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and saturated (PC 12:0; 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC)) lipid as membrane mimics. Additionally, we studied the effect of cholesterol on the protein-membrane interaction. Steady-state as well as time-resolved fluorescence spectroscopy, isothermal titration calorimetry (ITC), and ζ-potential measurements were used for the determination of the binding constants for the wild-type (WT) and single-site tryptophan mutants. Single-site tryptophan mutants were designed to make sure that the tryptophan residues sample different surface exposures in different mutants. In the absence of cholesterol, the membrane-binding affinities of the partially exposed and buried tryptophan mutants (Y5W and Y48W, respectively) were found to be greater than those of the WT protein. In the presence of cholesterol, the binding constants of the WT and Y48W mutant were found to decrease with an increase in cholesterol concentration. This was in contrast to that in the Y5W and F77W mutants, in which the binding constants increased on adding cholesterol. The present study highlights the interplay among the conformational architecture of a protein, its interaction with the membrane, and membrane composition in modulating the survival of a Leishmania parasite inside host macrophages.

Using Tryptophan Mutants To Probe the Structural and Functional Status of BsSCO, a Copper Binding, Cytochrome c Oxidase Assembly Protein from Bacillus subtilis.

PubMed

Hussain, Shina; Andrews, Diann; Hill, Bruce C

2017-12-05

The synthesis of cytochrome c oxidase protein from Bacillus subtilis (i.e., BsSCO) binds copper with picomolar affinity, which increases the protein's melting temperature (i.e., T M ) by 20 °C. Here two native tryptophans (i.e., W36 and W101) are identified as major contributors to BsSCO's structural form, and their contributions to the stability, intrinsic fluorescence, and copper binding properties of BsSCO are explored. Single mutations of tryptophan to phenylalanine decrease the T M by 10 °C and the folding free energy by 3-4 kcal/mol. A more severe change to alanine (i.e., W36A BsSCO) decreases the T M by 20 °C and the stability by 9 kcal/mol. However, these mutants bind copper with high affinity and assemble cytochrome c oxidase in vivo. Replacing phenylalanine at a position near (∼5 Å) the copper binding site with tryptophan (i.e., F42W) increases the T M of apo-BsSCO by 3 °C but diminishes the effect of copper binding. When both native tryptophans are changed to alanine, apo-BsSCO is unfolded in vitro and is not functional in cytochrome c oxidase assembly in vivo. A double-mutant of BsSCO in which W36A is combined with F42W exhibits a form of metastability. Apo-W36A/F42W BsSCO melts at 37 °C, which upon binding of copper shifts to 65 °C. B. subtilis expressing W36A/F42W BsSCO and grown at 37 °C does not assemble cytochrome c oxidase. However, when these cells are cooled to 25 °C, cytochrome c oxidase activity is recovered. Our results illustrate the subtle relationship between the structural stability and functional properties of BsSCO in the assembly of cytochrome c oxidase.

Marker-assisted pyramiding of opaque2 and novel opaque16 genes for further enrichment of lysine and tryptophan in sub-tropical maize.

PubMed

Sarika, Konsam; Hossain, Firoz; Muthusamy, Vignesh; Zunjare, Rajkumar U; Baveja, Aanchal; Goswami, Rajat; Bhat, Jayant S; Saha, Supradip; Gupta, Hari S

2018-07-01

The improvement of protein quality in maize so far has been based on recessive opaque2 (o2) mutant that along with endosperm-modifiers led to development of quality protein maize (QPM). Recent discovery of nutritional benefits of recessive opaque16 (o16) mutant was of immense significance for further improvement of protein quality. In the present study, o16 was introgressed into o2-based parental inbreds (HKI161, HKI193-1, HKI193-2 and HKI163) of four commercial QPM hybrids (HQPM-1, HQPM-4, HQPM-5 and HQPM-7) released in India, using marker-assisted backcross breeding. Background selection led to high recovery of recurrent parent genome (RPG) to maximum of 95%, and introgressed progenies showed considerable phenotypic resemblance for plant-, ear- and grain- characteristics to their respective recurrent parents. Selection of markers for o2 and o16 led to development of pyramided lines (o2o2/o16o16) that possessed as high as 76% and 91% more lysine and tryptophan over the recurrent parents, respectively. Reconstituted hybrids showed an average enhancement of 49% and 60% in lysine and tryptophan over the original hybrids, with highest enhancement amounting 64% and 86%, respectively. This is first report of enhancement of both lysine and tryptophan by o16 in maize genotypes adaptable to sub-tropics. Moderate variation in lysine and tryptophan was also observed in pyramided lines. Multi-location evaluation of reconstituted hybrids revealed similar grain yield and attributing traits to their original versions. This study signified the role of o16 as supplementary to o2 for nutritional quality enhancement in maize, and improved elite inbreds and hybrids developed here hold great significance in maize biofortification programme. Copyright © 2018 Elsevier B.V. All rights reserved.

Repeated chlorpromazine administration increases a behavioural response of rats to 5-hydroxytryptamine receptor stimulation.

PubMed Central

Green, A R

1977-01-01

1 The hyperactivity syndrome produced in rats by administration of tranylcypromine (20 mg/kg i.p.) followed 30 min later by L-tryptophan (50 mg/kg i.p.) is generally considered to be due to increased 5-hydroxytryptamine (5-HT) functional activity. It is inhibited by chlorpromazine (30 mg/kg i.p.) injected 60 min before the tranylcypromine. However, chlorpromazine injection for 4 days either at a dose of 30 mg/kg once daily or 5 mg/kg twice daily results in an enhanced hyperactivity response to tranylcypromine and L-tryptophan administration 24 h after the final dose of chlorpromazine. 2 One injection of chlorpromazine (30 mg/kg) did not produce enhancement 24 h later and the inhibition of the tranylcypromine/L-tryptophan hyperactivity observed after acute chlorpromazine injection was seen if the rats were given tranylcypromine and L-tryptophan 1 h after the fourth chlorpromazine (30 mg/kg) dose. 3 Chlorpromazine (30 mg/kg) once daily or 5 mg/kg twice daily for 4 days resulted in rats displaying enhanced behavioral responses to the suggested 5-HT agonist 5-methoxy N,N-dimethyltryptamine (2 mg/kg) on day 5. 4 Chlorpromazine (30 mg/kg) once daily for 4 days produces a slight increase in brain 5-hydroxytryptamine (5-HT) concentration on day 5, but no difference in the rate of brain 5-HT synthesis or the rate of 5-HT accumulation after tranylcypromine and L-tryptophan administration. 5. There is some evidence that chlorpromazine blocks 5-HT receptors. It has also been observed that several other neuroleptic drugs do not produce enhanced 5-HT responses after repeated administration. It is suggested therefore that the enhanced behavioural response to 5-HT receptor stimulation following repeated chlorpromazine administration may be because this drug blocks 5-HT receptors. PMID:264797

Structure-activity relationships of N-beta-phenylpropionyl-L-tyrosine and its derivatives on the inhibition of an identifiable giant neurone of an African giant snail (Achatina fulica Férussac).

PubMed Central

Ariyoshi, Y.; Takeuchi, H.

1982-01-01

1 Inhibitory effects of N-beta-phenylpropionyl-L-tyrosine, N-beta-phenylpropionyl-L-tryptophan and their derivatives on an identifiable giant neurone, TAN (tonically autoactive neurone) of an African giant snail (Achatina fulica Férussac) were examined in an attempt to elucidate which structural features are necessary to produce the effect. 2 Of the compounds examined, N-beta-cyclohexylpropionyl-L-tyrosine showed the strongest effect. Its critical concentration (c.c.) was 3 X 10(-8)-10(-7)M, about ten times lower than that of N-beta-phenylpropionyl-L-tyrosine (c.c., 3 X 10(-7)-10(-6)M). N-beta-cyclohexylpropionyl-L-tryptophan (c.c., 10(-6)M) had an effect almost similar to that of N-beta-phenylpropionyl-L-tryptophan (c.c., 10(-6)M). 3 N-beta-Phenylpropionyl-N-methyl-L-tyrosine had no effect at a high concentration. 4 Effects of N-beta-phenylpropionyl-L-tyrosine amide (c.c., 3 X 10(-7)-10(-6)M) and N-beta-phenylpropionyl-L-tryptophan amide (c.c., 10(-6)M) were very similar to those of N-beta-phenylpropionyl-L-tyrosine and N-beta-phenylpropionyl-L-tryptophan respectively. 5 N-beta-Phenylpropionyl-p-amino-L-phenylalanine (c.c., 3 X 10(-5)-10(-4)M) and N-beta-phenylpropionyl-p-chloro-L-phenylalanine (c.c., 10(-4)M) had only a weak effect. 6 It is proposed that the structural features producing the effect are as follows: the active compound has a phenyl or a cyclohexyl group (hydrophobic binding group), after a suitable distance a peptide bond (proton donor and proton acceptor), adjacently a carbonyl group (proton acceptor), and a phenolic hydroxyl or an indolyl imino group (proton donor) in the molecule. PMID:7150871

Potential rainfall-intensity and pH-driven shifts in the apparent fluorescent composition of dissolved organic matter in rainwater.

PubMed

Zhou, Yongqiang; Yao, Xiaolong; Zhang, Yibo; Shi, Kun; Zhang, Yunlin; Jeppesen, Erik; Gao, Guang; Zhu, Guangwei; Qin, Boqiang

2017-05-01

Perturbations of rainwater chromophoric dissolved organic matter (CDOM) fluorescence induced by changes in rainfall intensity and pH were investigated by field observations and laboratory pH titrations. Microbial humic-like fluorophores dominated the rainwater CDOM pool, followed by tryptophan-like and tyrosine-like substances. Increased rainfall intensity had notable dilution effects on all six fluorescent components (C1-C6) identified using parallel factor (PARAFAC) analysis, the effect being especially pronounced for the microbial humic-like C1, tryptophan-like C3, and tyrosine-like C5. The results also indicated that increasing pH from 7 to 9 led to decreased fluorescence intensity (F max ) of all the six components, while a pH increase from 5 to 7, resulted in increasing F max of terrestrial humic-like C2, tyrosine-like C5, and tryptophan-like C6 and decreasing microbial humic-like C1, tryptophan-like C3, and fulvic-like C4. Two-dimensional correlation spectroscopy (2D-COS) demonstrated that synchronous fluorescence responded first to pH modifications at fulvic-like wavelength (λ Ex /λ Em  = ∼316/416 nm), followed by tyrosine-like wavelength (λ Ex /λ Em  = ∼204/304 nm), tryptophan-like wavelength (λ Ex /λ Em  = ∼226/326 nm), microbial humic-like wavelength (∼295/395 nm), and finally terrestrial humic-like wavelength (∼360/460 nm). Our results suggest that a decrease in areas affected by acid rain in South China occurring at present may possibly result in apparent compositional changes of CDOM fluorescence. The decreased rainfall in South-West China and increased rainfall in North-West China during the past five decades may possibly accordingly result in increased and decreased F max of all the six components identified in South-West and North-West China, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Urinary metabolomics of young Italian autistic children supports abnormal tryptophan and purine metabolism.

PubMed

Gevi, Federica; Zolla, Lello; Gabriele, Stefano; Persico, Antonio M

2016-01-01

Autism spectrum disorder (ASD) is still diagnosed through behavioral observation, due to a lack of laboratory biomarkers, which could greatly aid clinicians in providing earlier and more reliable diagnoses. Metabolomics on human biofluids provides a sensitive tool to identify metabolite profiles potentially usable as biomarkers for ASD. Initial metabolomic studies, analyzing urines and plasma of ASD and control individuals, suggested that autistic patients may share some metabolic abnormalities, despite several inconsistencies stemming from differences in technology, ethnicity, age range, and definition of "control" status. ASD-specific urinary metabolomic patterns were explored at an early age in 30 ASD children and 30 matched controls (age range 2-7, M:F = 22:8) using hydrophilic interaction chromatography (HILIC)-UHPLC and mass spectrometry, a highly sensitive, accurate, and unbiased approach. Metabolites were then subjected to multivariate statistical analysis and grouped by metabolic pathway. Urinary metabolites displaying the largest differences between young ASD and control children belonged to the tryptophan and purine metabolic pathways. Also, vitamin B 6 , riboflavin, phenylalanine-tyrosine-tryptophan biosynthesis, pantothenate and CoA, and pyrimidine metabolism differed significantly. ASD children preferentially transform tryptophan into xanthurenic acid and quinolinic acid (two catabolites of the kynurenine pathway), at the expense of kynurenic acid and especially of melatonin. Also, the gut microbiome contributes to altered tryptophan metabolism, yielding increased levels of indolyl 3-acetic acid and indolyl lactate. The metabolic pathways most distinctive of young Italian autistic children largely overlap with those found in rodent models of ASD following maternal immune activation or genetic manipulations. These results are consistent with the proposal of a purine-driven cell danger response, accompanied by overproduction of epileptogenic and excitotoxic quinolinic acid, large reductions in melatonin synthesis, and gut dysbiosis. These metabolic abnormalities could underlie several comorbidities frequently associated to ASD, such as seizures, sleep disorders, and gastrointestinal symptoms, and could contribute to autism severity. Their diagnostic sensitivity, disease-specificity, and interethnic variability will merit further investigation.

Probiotic Supplements Beneficially Affect Tryptophan–Kynurenine Metabolism and Reduce the Incidence of Upper Respiratory Tract Infections in Trained Athletes: A Randomized, Double-Blinded, Placebo-Controlled Trial

PubMed Central

Strasser, Barbara; Geiger, Daniela; Schauer, Markus; Gostner, Johanna M.; Gatterer, Hannes; Burtscher, Martin; Fuchs, Dietmar

2016-01-01

Background: Prolonged intense exercise has been associated with transient suppression of immune function and an increased risk of infections. In this context, the catabolism of amino acid tryptophan via kynurenine may play an important role. The present study examined the effect of a probiotic supplement on the incidence of upper respiratory tract infections (URTI) and the metabolism of aromatic amino acids after exhaustive aerobic exercise in trained athletes during three months of winter training. Methods: Thirty-three highly trained individuals were randomly assigned to probiotic (PRO, n = 17) or placebo (PLA, n = 16) groups using double blind procedures, receiving either 1 × 1010 colony forming units (CFU) of a multi-species probiotic (Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Enterococcus faecium W54, Lactobacillus acidophilus W22, Lactobacillus brevis W63, and Lactococcus lactis W58) or placebo once per day for 12 weeks. The serum concentrations of tryptophan, phenylalanine and their primary catabolites kynurenine and tyrosine, as well as the concentration of the immune activation marker neopterin were determined at baseline and after 12 weeks, both at rest and immediately after exercise. Participants completed a daily diary to identify any infectious symptoms. Results: After 12 weeks of treatment, post-exercise tryptophan levels were lowered by 11% (a significant change) in the PLA group compared to the concentrations measured before the intervention (p = 0.02), but remained unchanged in the PRO group. The ratio of subjects taking the placebo who experienced one or more URTI symptoms was increased 2.2-fold compared to those on probiotics (PLA 0.79, PRO 0.35; p = 0.02). Conclusion: Data indicate reduced exercise-induced tryptophan degradation rates in the PRO group. Daily supplementation with probiotics limited exercise-induced drops in tryptophan levels and reduced the incidence of URTI, however, did not benefit athletic performance. PMID:27886064

Metabolite Profile Analysis Reveals Functional Effects of 28-Day Vitamin B-6 Restriction on One-Carbon Metabolism and Tryptophan Catabolic Pathways in Healthy Men and Women123

PubMed Central

da Silva, Vanessa R.; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A.; Midttun, Øivind; Quinlivan, Eoin P.; Garrett, Timothy J.; Coats, Bonnie; Shankar, Meena N.; Percival, Susan S.; Chi, Yueh-Yun; Muller, Keith E.; Ueland, Per Magne; Stacpoole, Peter W.; Gregory, Jesse F.

2013-01-01

Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5′-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (<0.35 mg/d). liquid chromatography-tandem mass spectrometry analysis of the compounds relevant to one-carbon metabolism showed that vitamin B-6 restriction yielded increased cystathionine (53% pre- and 76% postprandial; P < 0.0001) and serine (12% preprandial; P < 0.05), and lower creatine (40% pre- and postprandial; P < 0.0001), creatinine (9% postprandial; P < 0.05), and dimethylglycine (16% postprandial; P < 0.05) relative to the vitamin B-6–adequate state. In the tryptophan pathway, vitamin B-6 restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P < 0.01) and higher 3-hydroxykynurenine (39% pre- and 34% postprandial; P < 0.01). Multivariate ANOVA analysis showed a significant global effect of vitamin B-6 restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency. PMID:23966327

The Interactions Between Kynurenine, Folate, Methionine and Pteridine Pathways in Obesity.

PubMed

Engin, Ayse Basak; Engin, Atilla

2017-01-01

Obesity activates both innate and adaptive immune responses in adipose tissue. Elevated levels of eosinophils with depression of monocyte and neutrophil indicate the deficiencies in the immune system of morbidly obese individuals. Actually, adipose tissue macrophages are functional antigen-presenting cells that promote the proliferation of interferon-gamma (IFN-gamma)-producing CD4+ T cells in adipose tissue of obese subjects. Eventually, diet-induced obesity is associated with the loss of tissue homeostasis and development of type 1 inflammatory responses in visceral adipose tissue. Activity of inducible indoleamine 2,3-dioxygenase-1 (IDO-1) plays a major role under pro-inflammatory, IFN-gamma dominated settings. One of the two rate-limiting enzymes which can metabolize tryptophan to kynurenine is IDO-1. Tumor necrosis factor-alpha (TNF-alpha) correlates with IDO-1 in adipose compartments. Actually, IDO-1-mediated tryptophan catabolism due to chronic immune activation is the cause of reduced tryptophan plasma levels and be considered as the driving force for food intake in morbidly obese patients. Thus, decrease in plasma tryptophan levels and subsequent reduction in serotonin (5-HT) production provokes satiety dysregulation that leads to increased caloric uptake and obesity. However, after bariatric surgery, weight reduction does not lead to normalization of IDO-1 activity. Furthermore, there is a connection between arginine and tryptophan metabolic pathways in the generation of reactive nitrogen intermediates. Hence, abdominal obesity is associated with vascular endothelial dysfunction and reduced nitric oxide (NO) availability. IFN-gamma-induced activation of the inducible nitric oxide synthase (iNOS) and dissociation of endothelial adenosine monophosphate activated protein kinase (AMPK)- phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt)- endothelial NO synthase (eNOS) pathway enhances oxidative stress production secondary to high-fat diet. Thus, reduced endothelial NO availability correlates with the increase in plasma non-esterified fatty acids and triglycerides levels. Additionally, in obese patients, folate-deficiency leads to hyperhomocysteinemia. Folic acid confers protection against hyperhomocysteinemia-induced oxidative stress.

Gallium uptake in tryptophan-related pulmonary disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, S.M.; Park, C.H.; Intenzo, C.M.

1991-02-01

We describe a patient who developed fever, fatigue, muscle weakness, dyspnea, skin rash, and eosinophilia after taking high doses of tryptophan for insomnia for two years. A gallium-67 scan revealed diffuse increased uptake in the lung and no abnormal uptake in the muscular distribution. Bronchoscopy and biopsy confirmed inflammatory reactions with infiltration by eosinophils, mast cells, and lymphocytes. CT scan showed an interstitial alveolar pattern without fibrosis. EMG demonstrated diffuse myopathy. Muscle biopsy from the right thigh showed an inflammatory myositis with eosinophilic and lymphocytic infiltrations.

Contribution of Tryptophan Residues to the Combining Site of a Monoclonal Anti Dinitrophenyl Spin-Label Antibody

DTIC Science & Technology

1987-01-01

identified in the difference spectra, implying that: there are five to seven tryptophans within 17 A of the spin-label hapten. Amino acid sequences...of the heavy, and light chains were obtained by a combination of amino acid and DNA sequencing. A molecular model’ was constructed from the sequence...Clore & acids yields detailed information about the amino acid com- Gronenborn, 1982, 1983). This technique should also identify position of the combining

Targeting Tryptophan Catabolism: A Novel Method to Block Triple-Negative Breast Cancer Metastasis

DTIC Science & Technology

2016-04-01

in many immune cell types and its activation decreases T-cell activity leading to tumor immune escape. Since the rate limiting enzyme TDO2 increases...What were the major goals of the project? Our overall goals were to test the hypotheses that the ability to upregulate kynurenine via the enzyme TDO2...discipline(s) of the project? " o This research is strongly suggesting that TDO2 is likely the primary enzyme that catabolizes tryptophan that should

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Determination of photophysical parameters of tryptophan molecules by methods of laser fluorimetry

NASA Astrophysics Data System (ADS)

Banishev, A. A.; Shirshin, E. A.; Fadeev, V. V.

2008-01-01

The photophysical parameters of tryptophan molecules at a low concentration in aqueous solution are measured by the methods of nanosecond laser fluorimetry upon excitation by 266-nm laser pulses. Two-step processes (reversible and irreversible photochemical transformations) taking place in this case are described quantitatively and it is shown that they can be neglected at the exciting photon flux density F < 5×1024 cm-2 s-1 in ~10-ns pulses.

On the role of brain serotonin in expression of genetic predisposition to catalepsy in animal models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popova, N.K.; Kulikov, A.V.

1995-06-19

The activity of the rate-limiting enzyme of serotonin biosynthesis, tryptophan hydroxylase, in the striatum but not in the hippocampus and midbrain of rats bred for predisposition to catalepsy was higher than in nonselected rats. Mice of the highly susceptible to catalepsy CBA strain also differed from other noncataleptic mouse strains by the highest tryptophan hydroxylase activity in the striatum. Inhibition of tryptophan hydroxylase with p-chlorophenylalanine and p-chloromethamphetamine drastically decreased immobility time in hereditary predisposed to catalepsy animals. A decrease in the {sup 3}H-ketanserin specific binding in the striatum of cataleptic rats and CBA mice was found. It was suggested thatmore » this decrease in 5-HT2A serotonin receptor density represented a down regulation of the receptors due to an activation of serotonergic transmission in striatum. It is suggested that hereditary catalepsy may be resulted from genetic changes in the regulation of serotonin metabolism in striatum. 32 refs., 6 figs.« less

Hypothalamic digoxin, hemispheric chemical dominance, and sleep.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2003-04-01

The isoprenoid path way produces endogenous digoxin, a substance that can regulate neurotransmitter and amino acid transport. Digoxin synthesis and neurotransmitter patterns were assessed in individuals with chronic insomnia. The patterns were compared in those with right hemispheric and left hemispheric dominance. The activity of HMG GoA reductase and serum levels of digoxin, magnesium, tryptophan catabolites, and tyrosine catabolites were measured in individuals with chronic insomnia and in individuals with differing hemispheric dominance. Digoxin synthesis was increased with upregulated tryptophan catabolism (increased levels of serotonin, strychnine, and nicotine), and downregulated tyrosine catabolism (decreased levels of dopamine, noradrenaline, and morphine) in those with chronic insomnia and right hemispheric chemical dominance. Digoxin synthesis was reduced with downregulated tryptophan catabolism (decreased levels of serotonin, strychnine, and nicotine) and upregulated tyrosine catabolism (increased levels of dopamine, noradrenaline, and morphine) in those with normal sleep patterns and left hemispheric chemical dominance. Hypothalamic digoxin plays a central role in the regulation of sleep behavior. Hemispheric chemical dominance in relation to digoxin status is also crucial.

Biosynthesis of indigo using recombinant E. coli: Development of a biological system for the cost-effective production of a large volume chemical

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, A.; Battist, S.; Chotani, G.

1995-11-01

Cost-effective production of any large-volume chemical by fermentation requires extensive manipulation of both the production organism and the fermentation and recovery processes. We have developed a recombinant E. coli system for the production of tryptophan and several other products derived from the aromatic amino acid pathway. By linking our technology for low-cost production of tryptophan from glucose with the enzyme naphthalene dioxygenase (NDO), we have achieved an overall process for the production of indigo dye from glucose. To successfully join these two technologies, both the tryptophan pathway and NDO were extensively modified via genetic engineering. In addition, systems were developedmore » to remove deleterious by-products generated during the chemical oxidations leading to indigo formation. Low-cost fermentation processes were developed that utilized minimal-salts media containing glucose as the sole carbon source. Finally, economical recovery processes were used that preserved the environmental friendliness of the biosynthetic route to indigo.« less

Effect of N-Terminal Acylation on the Activity of Myostatin Inhibitory Peptides.

PubMed

Takayama, Kentaro; Nakamura, Akari; Rentier, Cédric; Mino, Yusaku; Asari, Tomo; Saga, Yusuke; Taguchi, Akihiro; Yakushiji, Fumika; Hayashi, Yoshio

2016-04-19

Inhibition of myostatin, which negatively regulates skeletal muscle growth, is a promising strategy for the treatment of muscle atrophic disorders, such as muscular dystrophy, cachexia and sarcopenia. Recently, we identified peptide A (H-WRQNTRYSRIEAIKIQILSKLRL-NH2 ), the 23-amino-acid minimum myostatin inhibitory peptide derived from mouse myostatin prodomain, and highlighted the importance of its N-terminal tryptophan residue for the effective inhibition. In this study, we synthesized a series of acylated peptide derivatives focused on the tryptophan residue to develop potent myostatin inhibitors. As a result of the investigation, a more potent derivative of peptide A was successfully identified in which the N-terminal tryptophan residue is replaced with a 2-naphthyloxyacetyl moiety to give an inhibitory peptide three times (1.19±0.11 μm) more potent than parent peptide A (3.53±0.25 μm). This peptide could prove useful as a new starting point for the development of improved inhibitory peptides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

RNA Editing in Plant Mitochondria

NASA Astrophysics Data System (ADS)

Hiesel, Rudolf; Wissinger, Bernd; Schuster, Wolfgang; Brennicke, Axel

1989-12-01

Comparative sequence analysis of genomic and complementary DNA clones from several mitochondrial genes in the higher plant Oenothera revealed nucleotide sequence divergences between the genomic and the messenger RNA-derived sequences. These sequence alterations could be most easily explained by specific post-transcriptional nucleotide modifications. Most of the nucleotide exchanges in coding regions lead to altered codons in the mRNA that specify amino acids better conserved in evolution than those encoded by the genomic DNA. Several instances show that the genomic arginine codon CGG is edited in the mRNA to the tryptophan codon TGG in amino acid positions that are highly conserved as tryptophan in the homologous proteins of other species. This editing suggests that the standard genetic code is used in plant mitochondria and resolves the frequent coincidence of CGG codons and tryptophan in different plant species. The apparently frequent and non-species-specific equivalency of CGG and TGG codons in particular suggests that RNA editing is a common feature of all higher plant mitochondria.

Hypothalamic digoxin, hemispheric chemical dominance, and spirituality.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2003-03-01

The isoprenoid pathway was assessed in atheistic and spiritually inclined individuals. The pathway was also assessed in individuals with differing hemispheric dominance to assess whether hemispheric dominance has a correlation with spiritual and atheistic tendency. HMG CoA reductase activity, serum digoxin, RBC membrane Na(+)-K+ ATPase activity, serum magnesium, and tyrosine/tryptophan catabolic patterns were assessed in spiritual/atheistic individuals and in those differing hemispheric dominance. In spiritually-inclined individuals, there was increased digoxin synthesis, decreased membrane Na(+)-K+ ATPase activity, increased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and decreased tyrosine catabolites (dopamine, noradrenaline, and morphine). The pattern in spiritually-inclined individuals correlated with right hemispheric chemical dominance. In atheistic individuals there was decreased digoxin synthesis, increased membrane Na(+)-K+ ATPase activity, decreased tryptophan catabolities (serotonin, quinolinic acid, and nicotine), and increased tyrosine catabolites (dopamine, noradrenaline, and morphine). This pattern in atheistic individuals correlated with that obtained in left hemispheric chemical dominance. Hemispheric chemical dominance and hypothalamic digoxin could regulate the predisposition to spirituality or atheism.

UV-radiation Induced Disruption of Dry-Cavities in Human γD-crystallin Results in Decreased Stability and Faster Unfolding

PubMed Central

Xia, Zhen; Yang, Zaixing; Huynh, Tien; King, Jonathan A.; Zhou, Ruhong

2013-01-01

Age-onset cataracts are believed to be expedited by the accumulation of UV-damaged human γD-crystallins in the eye lens. Here we show with molecular dynamics simulations that the stability of γD-crystallin is greatly reduced by the conversion of tryptophan to kynurenine due to UV-radiation, consistent with previous experimental evidences. Furthermore, our atomic-detailed results reveal that kynurenine attracts more waters and other polar sidechains due to its additional amino and carbonyl groups on the damaged tryptophan sidechain, thus breaching the integrity of nearby dry center regions formed by the two Greek key motifs in each domain. The damaged tryptophan residues cause large fluctuations in the Tyr-Trp-Tyr sandwich-like hydrophobic clusters, which in turn break crucial hydrogen-bonds bridging two β-strands in the Greek key motifs at the “tyrosine corner”. Our findings may provide new insights for understanding of the molecular mechanism of the initial stages of UV-induced cataractogenesis. PMID:23532089

Lack of Tryptophan Hydroxylase-1 in Mice Results in Gait Abnormalities

PubMed Central

Suidan, Georgette L.; Vanderhorst, Veronique; Hampton, Thomas G.; Wong, Siu Ling; Voorhees, Jaymie R.; Wagner, Denisa D.

2013-01-01

The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (−/−) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system. PMID:23516593

Lack of tryptophan hydroxylase-1 in mice results in gait abnormalities.

PubMed

Suidan, Georgette L; Duerschmied, Daniel; Dillon, Gregory M; Vanderhorst, Veronique; Hampton, Thomas G; Wong, Siu Ling; Voorhees, Jaymie R; Wagner, Denisa D

2013-01-01

The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (-/-) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system.

Inhibiting the photosensitized oxidation of anthracene and tryptophan by means of natural antioxidants

NASA Astrophysics Data System (ADS)

Aksenova, N. A.; Vyzhlova, E. N.; Malinovskaya, V. V.; Parfenov, V. V.; Solov'eva, A. B.; Timashev, P. S.

2013-08-01

It is shown that model reactions of photosensitized oxidation of anthracene and tryptophan can be used for evaluation and comparison of antioxidant activity of various classes of compounds. Inhibition of the oxidation of substrates in the presence of the familiar antioxidants tocopherol (vitamin E), ascorbic acid (vitamin C), and mixtures of these vitamins with methionine, and in the presence of reputed antioxidants dihydroquercetin and taurine, are considered. It is concluded that all of the above compounds except for taurine have antioxidant properties; i.e., they reduce the rate constants of the photosensitized oxidation of anthracene and tryptophan. It is found that the inhibition of oxidation is associated with the interaction between antioxidants and singlet oxygen. Analysis of the kinetic dependences of the photosensitized oxidation of substrates in the presence of antioxidants reveals that a mixture of vitamins inhibits the process most efficiently, and inhibition occurs at the initial stages due to more active interaction between singlet oxygen and vitamin C

Docking studies of antidepressants against single crystal structure of tryptophan 2, 3-dioxygenase using Molegro Virtual Docker software.

PubMed

Dawood, Shazia; Zarina, Shamshad; Bano, Samina

2014-09-01

Tryptophan 2, 3-dioxygenase (TDO) a heme containing enzyme found in mammalian liver is responsible for tryptophan (Trp) catabolism. Trp is an essential amino acid that is degraded in to N-formylkynurenine by the action of TDO. The protein ligand interaction plays a significant role in structural based drug designing. The current study illustrates the binding of established antidepressants (ADs) against TDO enzyme using in-silico docking studies. For this purpose, Fluoxetine, Paroxetine, Sertraline, Fluvoxamine, Seproxetine, Citalopram, Moclobamide, Hyperforin and Amoxepine were selected. In-silico docking studies were carried out using Molegro Virtual Docker (MVD) software. Docking results show that all ADs fit well in the active site of TDO moreover Hyperforin and Paroxetine exhibited high docking scores of -152.484k cal/mol and -139.706k cal/mol, respectively. It is concluded that Hyperforin and Paroxetine are possible lead molecules because of their high docking scores as compared to other ADs examined. Therefore, these two ADs stand as potent inhibitors of TDO enzyme.

Plasmid ColE1 as a Molecular Vehicle for Cloning and Amplification of DNA

PubMed Central

Hershfield, Vickers; Boyer, Herbert W.; Yanofsky, Charles; Lovett, Michael A.; Helinski, Donald R.

1974-01-01

DNA fragments obtained from EcoRI endonuclease digestion of bacteriophage ϕ80pt190 (trp+) and the plasmid ColE1 were covalently joined with polynucleotide ligase. Transformation of Escherichia coli trp- strains to tryptophan independence with the recombined DNA selected for reconstituted ColE1 plasmids containing the tryptophan operon and the ϕ80 immunity region. Similarly, an EcoRI endonuclease generated fragment of plasmid pSC105 DNA containing the genetic determinant of kanamycin resistance was inserted into the ColE1 plasmid and recovered in E. coli. The plasmids containing the trp operon (ColE1-trp) and the kanamycin resistance gene were maintained under logarithmic growth conditions at a level of 25-30 copies per cell and accumulate to the extent of several hundred copies per cell in the presence of chloramphenicol. Cells carrying the ColE1-trp plasmid determined the production of highly elevated levels of trp operon-specific mRNA and tryptophan biosynthetic enzymes. Images PMID:4610576

Kynurenine Pathway Metabolism is Involved in the Maintenance of the Intracellular NAD+ Concentration in Human Primary Astrocytes

PubMed Central

Grant, Ross; Nguyen, Susan; Guillemin, Gilles

2010-01-01

Efficient synthesis of NAD+ is critical to maintaining cell viability in all organs of the body. However, little is known of the pathway(s) by which cells of the central nervous system produce NAD+. The aim of this study was to investigate the relationship, between tryptophan degradation via the kynurenine pathway (KP) and de novo NAD+ synthesis in human astrocytes, a major cell type within the brain. In this study we observed that inhibition of single enzymes of the KP resulted in significant decreases in NAD+ levels in astroglial cells after a 24 hr period. We also observed that astrocytes cultured in media deficient in tryptophan, nicotinic acid and nicotinamide resulted in a 50% decrease in NAD+ levels after 24 hrs. This decrease in NAD+ was partially restored by supplementation of the culture media with either tryptophan or kynurenine, or nicotinic acid or with supply of the salvage pathway precursor nicotinamide. PMID:22084595

Specificity of the Acute Tryptophan and Tyrosine Plus Phenylalanine Depletion and Loading Tests I. Review of Biochemical Aspects and Poor Specificity of Current Amino Acid Formulations

PubMed Central

Badawy, Abdulla A.-B.; Dougherty, Donald M.; Richard, Dawn M.

2010-01-01

The acute tryptophan or tyrosine plus phenylalanine depletion and loading tests are powerful tools for studying the roles of serotonin, dopamine and noradrenaline in normal subjects and those with behavioural disorders. The current amino acid formulations for these tests, however, are associated with undesirable decreases in ratios of tryptophan or tyrosine plus phenylalanine to competing amino acids resulting in loss of specificity. This could confound biochemical and behavioural findings. Compositions of current formulations are reviewed, the biochemical principles underpinning the tests are revisited and examples of unintended changes in the above ratios and their impact on monoamine function and behaviour will be demonstrated from data in the literature. The presence of excessive amounts of the 3 branched-chain amino acids Leu, Ile and Val is responsible for these unintended decreases and the consequent loss of specificity. Strategies for enhancing the specificity of the different formulations are proposed. PMID:20676231

Specificity of the acute tryptophan and tyrosine plus phenylalanine depletion and loading tests I. Review of biochemical aspects and poor specificity of current amino Acid formulations.

PubMed

Badawy, Abdulla A-B; Dougherty, Donald M; Richard, Dawn M

2010-01-01

The acute tryptophan or tyrosine plus phenylalanine depletion and loading tests are powerful tools for studying the roles of serotonin, dopamine and noradrenaline in normal subjects and those with behavioural disorders. The current amino acid formulations for these tests, however, are associated with undesirable decreases in ratios of tryptophan or tyrosine plus phenylalanine to competing amino acids resulting in loss of specificity. This could confound biochemical and behavioural findings. Compositions of current formulations are reviewed, the biochemical principles underpinning the tests are revisited and examples of unintended changes in the above ratios and their impact on monoamine function and behaviour will be demonstrated from data in the literature. The presence of excessive amounts of the 3 branched-chain amino acids Leu, Ile and Val is responsible for these unintended decreases and the consequent loss of specificity. Strategies for enhancing the specificity of the different formulations are proposed.

Orthogonal use of a human tRNA synthetase active site to achieve multifunctionality.

PubMed

Zhou, Quansheng; Kapoor, Mili; Guo, Min; Belani, Rajesh; Xu, Xiaoling; Kiosses, William B; Hanan, Melanie; Park, Chulho; Armour, Eva; Do, Minh-Ha; Nangle, Leslie A; Schimmel, Paul; Yang, Xiang-Lei

2010-01-01

Protein multifunctionality is an emerging explanation for the complexity of higher organisms. In this regard, aminoacyl tRNA synthetases catalyze amino acid activation for protein synthesis, but some also act in pathways for inflammation, angiogenesis and apoptosis. It is unclear how these multiple functions evolved and how they relate to the active site. Here structural modeling analysis, mutagenesis and cell-based functional studies show that the potent angiostatic, natural fragment of human tryptophanyl-tRNA synthetase (TrpRS) associates via tryptophan side chains that protrude from its cognate cellular receptor vascular endothelial cadherin (VE-cadherin). VE-cadherin's tryptophan side chains fit into the tryptophan-specific active site of the synthetase. Thus, specific side chains of the receptor mimic amino acid substrates and expand the functionality of the active site of the synthetase. We propose that orthogonal use of the same active site may be a general way to develop multifunctionality of human tRNA synthetases and other proteins.

RNA-based regulation of genes of tryptophan synthesis and degradation, in bacteria

PubMed Central

Yanofsky, Charles

2007-01-01

We are now aware that RNA-based regulatory mechanisms are commonly used to control gene expression in many organisms. These mechanisms offer the opportunity to exploit relatively short, unique RNA sequences, in altering transcription, translation, and/or mRNA stability, in response to the presence of a small or large signal molecule. The ability of an RNA segment to fold and form alternative hairpin secondary structures—each dedicated to a different regulatory function—permits selection of specific sequences that can affect transcription and/or translation. In the present paper I will focus on our current understanding of the RNA-based regulatory mechanisms used by Escherichia coli and Bacillus subtilis in controlling expression of the tryptophan biosynthetic operon. The regulatory mechanisms they use for this purpose differ, suggesting that these organisms, or their ancestors, adopted different strategies during their evolution. I will also describe the RNA-based mechanism used by E. coli in regulating expression of its operon responsible for tryptophan degradation, the tryptophanase operon. PMID:17601995

Tryptophan Metabolism in Rat Liver After Administration of Tryptophan, Kynurenine Metabolites, and Kynureninase Inhibitors.

PubMed

Badawy, Abdulla A-B; Bano, Samina

2016-01-01

Rat liver tryptophan (Trp), kynurenine pathway metabolites, and enzymes deduced from product/substrate ratios were assessed following acute and/or chronic administration of kynurenic acid (KA), 3-hydroxykynurenine (3-HK), 3-hydroxyanthranilic acid (3-HAA), Trp, and the kynureni-nase inhibitors benserazide (BSZ) and carbidopa (CBD). KA activated Trp 2,3-dioxygenase (TDO), possibly by increasing liver 3-HAA, but inhibited kynurenine aminotransferase (KAT) and kynureninase activities with 3-HK as substrate. 3-HK inhibited kynureninase activity from 3-HK. 3-HAA stimulated TDO, but inhibited kynureninase activity from K and 3-HK. Trp (50 mg/kg) increased kynurenine metabolite concentrations and KAT from K, and exerted a temporary stimulation of TDO. The kynureninase inhibitors BSZ and CBD also inhibited KAT, but stimulated TDO. BSZ abolished or strongly inhibited the Trp-induced increases in liver Trp and kynurenine metabolites. The potential effects of these changes in conditions of immune activation, schizophrenia, and other disease states are discussed.

Cell Adhesion on RGD-Displaying Knottins with Varying Numbers of Tryptophan Amino Acids to Tune the Affinity for Assembly on Cucurbit[8]uril Surfaces.

PubMed

Sankaran, Shrikrishnan; Cavatorta, Emanuela; Huskens, Jurriaan; Jonkheijm, Pascal

2017-09-05

Cell adhesion is studied on multivalent knottins, displaying RGD ligands with a high affinity for integrin receptors, that are assembled on CB[8]-methylviologen-modified surfaces. The multivalency in the knottins stems from the number of tryptophan amino acid moieties, between 0 and 4, that can form a heteroternary complex with cucurbit[8]uril (CB[8]) and surface-tethered methylviologen (MV 2+ ). The binding affinity of the knottins with CB[8] and MV 2+ surfaces was evaluated using surface plasmon resonance spectroscopy. Specific binding occurred, and the affinity increased with the valency of tryptophans on the knottin. Additionally, increased multilayer formation was observed, attributed to homoternary complex formation between tryptophan residues of different knottins and CB[8]. Thus, we were able to control the surface coverage of the knottins by valency and concentration. Cell experiments with mouse myoblast (C2C12) cells on the self-assembled knottin surfaces showed specific integrin recognition by the RGD-displaying knottins. Moreover, cells were observed to elongate more on the supramolecular knottin surfaces with a higher valency, and in addition, more pronounced focal adhesion formation was observed on the higher-valency knottin surfaces. We attribute this effect to the enhanced coverage and the enhanced affinity of the knottins in their interaction with the CB[8] surface. Collectively, these results are promising for the development of biomaterials including knottins via CB[8] ternary complexes for tunable interactions with cells.

Meta-analysis of Cerebrospinal Fluid Cytokine and Tryptophan Catabolite Alterations in Psychiatric Patients: Comparisons Between Schizophrenia, Bipolar Disorder, and Depression.

PubMed

Wang, Alexandre K; Miller, Brian J

2018-01-13

Schizophrenia, bipolar disorder, and major depressive disorder (MDD) have all been associated with immune system dysfunction, including aberrant cerebrospinal fluid (CSF) levels of cytokines and tryptophan catabolites; however, the pattern of alterations has not been compared across disorders. We performed a meta-analysis of CSF cytokine and tryptophan catabolites in patients with these major psychiatric disorders. Articles were identified by searching Pub Med, PsycInfo, and Web of Science, and the reference lists of these studies. Twenty-eight studies met the inclusion criteria (16 schizophrenia, 4 bipolar disorder, and 9 MDD). CSF levels of IL-1β and kynurenic acid were significantly increased in patients with schizophrenia and bipolar disorder compared to healthy controls (P < .001). CSF levels of IL-6 and IL-8 were significantly increased in patients with schizophrenia and MDD compared to healthy controls (P ≤ .013). There is preliminary evidence for similarities in the pattern of CSF cytokine and tryptophan catabolite alterations across major psychiatric disorders, although findings must be interpreted with caution in light of small numbers of studies/subjects. Many CSF alterations are also concordant with those in the peripheral blood, particularly for schizophrenia. Findings have important implications for our understanding of the pathophysiology and treatment of major psychiatric disorders. © The Author(s) 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Effects of indoleamine 2,3-dioxygenase inhibitor in non-Hodgkin lymphoma model mice.

PubMed

Nakamura, Nobuhiko; Hara, Takeshi; Shimizu, Masahito; Mabuchi, Ryoko; Nagano, Junji; Ohno, Tomohiko; Kochi, Takahiro; Kubota, Masaya; Shirakami, Yohei; Goto, Naoe; Ito, Hiroyasu; Saito, Kuniaki; Tanaka, Takuji; Moriwaki, Hisataka; Tsurumi, Hisashi

2015-09-01

Indoleamine 2,3-dioxygenase (IDO) catalyzes the rate-limiting step in the metabolism of tryptophan along the kynurenine pathway. In tumors, increased IDO activity inhibits proliferation and induces apoptosis of T cells and natural killer cells. We investigated the therapeutic potential of IDO inhibitor 1-methyl-D-tryptophan (D-1MT) with cyclophosphamide (CY) in a mouse model of lymphoma. To examine the effect of D-1MT, mice were killed on day 28. Serum concentrations of L-kynurenine and L-tryptophan were measured by high-performance liquid chromatography. Regulatory T cells (Tregs) were counted by flow cytometry, and mRNA expressions of IDO1, Foxp3, IFN-γ, and COX-2 were examined by quantitative real-time reverse transcription-polymerase chain reaction. D-1MT+CY combination treatment significantly inhibited tumor growth as compared to either treatment alone. There were no significant differences in the serum L-kynurenine/L-tryptophan ratio or the IDO1 expression level in the tumors among the treatment groups. The expression levels of IFN-γ and COX-2 mRNA in tumor-draining lymph nodes (TDLNs) were found to be significantly up-regulated in the CY and D-1MT+CY groups. The number of Tregs in TDLNs in the D-1MT+CY group was significantly lower than that in CY groups on day 17. These results suggest that D-1MT in combination with CY is an effective treatment for lymphoma in a mouse model.

Effect of tryptophan-rich egg protein hydrolysate on brain tryptophan availability, stress and performance.

PubMed

Markus, C Rob; Verschoor, E; Firk, C; Kloek, J; Gerhardt, C C

2010-10-01

Reduced brain serotonin function is involved in stress-related disturbances and may particularly occur under chronic stress. Although serotonin production directly depends on the availability of its plasma dietary amino acid precursor tryptophan (TRP), previously described effects of tryptophan-rich food sources on stress-related behavior are rather modest. Recently, an egg protein hydrolysate (EPH) was developed that showed a much greater effect on brain TRP availability than pure TRP and other TRP-food sources and therefore may be more effective for performance under stress. The aim of the present study was to investigate the effects of EPH compared to placebo protein on plasma amino acids, stress coping and performance in subjects with high and low chronic stress vulnerabilities. In a placebo-controlled, double-blind, crossover study, 17 participants with high and 18 participants with low chronic stress vulnerabilities were monitored for mood and performance under acute stress exposure either following intake of EPH or placebo. EPH significantly increased plasma TRP availability for uptake into the brain, decreased depressive mood in all subjects and improved perceptual-motor and vigilance performance only in low chronic stress-vulnerable subjects. The acute use of a TRP-rich egg protein hydrolysate (EPH) is an adequate method to increase plasma TRP for uptake into the brain and may be beneficial for perceptual-motor and vigilance performance in healthy volunteers. Copyright © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Blunted epidermal L-tryptophan metabolism in vitiligo affects immune response and ROS scavenging by Fenton chemistry, part 1: Epidermal H2O2/ONOO(-)-mediated stress abrogates tryptophan hydroxylase and dopa decarboxylase activities, leading to low serotonin and melatonin levels.

PubMed

Schallreuter, Karin U; Salem, Mohamed A E L; Gibbons, Nick C J; Martinez, Aurora; Slominski, Radomir; Lüdemann, Jürgen; Rokos, Hartmut

2012-06-01

Vitiligo is characterized by a progressive loss of inherited skin color. The cause of the disease is still unknown. To date, there is accumulating in vivo and in vitro evidence for massive oxidative stress via hydrogen peroxide (H(2)O(2)) and peroxynitrite (ONOO(-)) in the skin of affected individuals. Autoimmune etiology is the favored theory. Since depletion of the essential amino acid L-tryptophan (Trp) affects immune response mechanisms, we here looked at epidermal Trp metabolism via tryptophan hydroxylase (TPH) with its downstream cascade, including serotonin and melatonin. Our in situ immunofluorescence and Western blot data reveal significantly lower TPH1 expression in patients with vitiligo. Expression is also low in melanocytes and keratinocytes under in vitro conditions. Although in vivo Fourier transform-Raman spectroscopy proves the presence of 5-hydroxytryptophan, epidermal TPH activity is completely absent. Regulation of TPH via microphthalmia-associated transcription factor and L-type calcium channels is severely affected. Moreover, dopa decarboxylase (DDC) expression is significantly lower, in association with decreased serotonin and melatonin levels. Computer simulation supports H(2)O(2)/ONOO(-)-mediated oxidation/nitration of TPH1 and DDC, affecting, in turn, enzyme functionality. Taken together, our data point to depletion of epidermal Trp by Fenton chemistry and exclude melatonin as a relevant contributor to epidermal redox balance and immune response in vitiligo.

Tryptophan and Cysteine Oxidation Products Dominate in α-Lactalbumin-Derived Peptides Analyzed with LC-MSn.

PubMed

Koivumäki, Tuuli P; Gürbüz, Göker; Heinonen, I Marina

2017-09-01

α-Lactalbumin (α-La), a major milk whey protein, is comprised of several amino acids prone to metal-catalyzed oxidation (MCO) typical in processing and during storage of foods. New tools are needed for the detection of characteristic oxidation products especially from tryptophan and cysteine that often remain unrecognized when using the traditional methods of carbonyl formation monitoring. In this study, the oxidative changes in α-La were investigated through tryptic digestion and collection of 3 descriptive peptides fitted into a metal-catalyzed oxidation (Fenton reaction) model. The peptide samples were oxidized at +37 °C for 14 d and explored with liquid chromatography-quadrupole ion trap-mass spectrometer (LC-MS n ). The fractionated α-La peptides were valyl-glycyl-isoleucyl-asparaginyl-tyrosyl-tryptophyl-leucyl-alanyl-histidyl-lysine (VGINYWLAHK), leucyl-aspartyl-glutaminyl-tryptophyl-leucyl-cysteinyl-glutamyl-lysine (LDQWLCEK), and tryptophyl +16 -leucyl-alanyl-histidyl-lysyl-alanyl-leucyl-cysteine (W +16 LAHKALC). Oxidation of several amino acids, such as cysteine, histidine, lysine, and tryptophan was observed. In the peptide LDQWLCEK, cysteine was rapidly trioxidized to sulfonic acid, followed by other amino acid side chains as secondary oxidation sites. Tryptophan oxidation was more pronounced in the peptides W +16 LAHKALC and VGINYWLAHK, and also formation of the harmful N-formylkynurenine was observed. As a conclusion, several stable and promising oxidation markers are proposed for α-La, which could be implemented in the evaluation of quality and safety of dairy protein-containing products. © 2017 Institute of Food Technologists®.

Plant native tryptophan synthase beta 1 gene is a non-antibiotic selection marker for plant transformation.

PubMed

Hsiao, Paoyuan; Sanjaya; Su, Ruey-Chih; Teixeira da Silva, Jaime A; Chan, Ming-Tsair

2007-03-01

Gene transformation is an integral tool for plant genetic engineering. All antibiotic resistant genes currently employed are of bacterial origin and their presence in the field is undesirable. Therefore, we developed a novel and efficient plant native non-antibiotic selection system for the selection of transgenic plants in the model system Arabidopsis. This new system is based on the enhanced expression of Arabidopsis tryptophan synthase beta 1 (AtTSB1) and the use of 5-methyl-tryptophan (5MT, a tryptophan [Trp] analog) and/or CdCl2 as selection agent(s). We successfully integrated an expression cassette containing an AtT-SB1 cDNA driven by a cauliflower mosaic virus 35S promoter into Arabidopsis by floral dip transformation. Transgenic plants were efficiently selected on MS medium supplemented with 75 microM 5MT or 300 microM CdCl2 devoid of antibiotics. TSB1 selection was as efficient as the conventional hygromycin selection system. Northern blot analysis of transgenic plants selected by 5MT and CdCl2 revealed increased TSB1 mRNA transcript whereas uneven transcript levels of hygromycin phosphotransferase II (hpt) (control) was observed. Gas chromatography-mass spectrometry revealed 10-15 fold greater free Trp content in AtT-SB1 transgenic plants than in wild-type plants grown with or without 5MT or CdCl2. Taken together, the TSB1 system provides a novel selection system distinct from conventional antibiotic selection systems.

Tryptophan scanning mutagenesis of the HERG K+ channel: the S4 domain is loosely packed and likely to be lipid exposed

PubMed Central

Subbiah, Rajesh N; Kondo, Mari; Campbell, Terence J; Vandenberg, Jamie I

2005-01-01

Inherited mutations or drug-induced block of voltage-gated ion channels, including the human ether-à-go-go-related gene (HERG) K+ channel, are significant causes of malignant arrhythmias and sudden death. The fourth transmembrane domain (S4) of these channels contains multiple positive charges that move across the membrane electric field in response to changes in transmembrane voltage. In HERG K+ channels, the movement of the S4 domain across the transmembrane electric field is particularly slow. To examine the basis of the slow movement of the HERG S4 domain and specifically to probe the relationship between the S4 domain with the lipid bilayer and rest of the channel protein, we individually mutated each of the S4 amino acids in HERG (L524–L539) to tryptophan, and characterized the activation and deactivation properties of the mutant channels in Xenopus oocytes, using two-electrode voltage-clamp methods. Tryptophan has a large bulky hydrophobic sidechain and so should be tolerated at positions that interact with lipid, but not at positions involved in close protein–protein interactions. Significantly, we found that all S4 tryptophan mutants were functional. These data indicate that the S4 domain is loosely packed within the rest of the voltage sensor domain and is likely to be lipid exposed. Further, we identified residues K525, R528 and K538 as being the most important for slow activation of the channels. PMID:16166152

Correlation of conformational heterogeneity of the tryptophyl side chain and time-resolved fluorescence intensity decay kinetics

NASA Astrophysics Data System (ADS)

Laws, William R.; Ross, J. B. Alexander

1992-04-01

The time-resolved fluorescence properties of a tryptophan residue should be useful for probing protein structure, function, and dynamics. To date, however, the non-single exponential fluorescence intensity decay kinetics for numerous peptides and proteins having a single tryptophan residue have not been adequately explained. Many possibilities have been considered and include: (1) contributions from the 1La and 1Lb states of indole; (2) excited-state hydrogen exchange; and (3) environmental heterogeneity from (chi) 1 and (chi) 2 rotamers. In addition, it has been suggested that generally many factors contribute to the decay and a distribution of probabilities may be more appropriate. Two recent results support multiple species due to conformational heterogeneity as the major contributor to complex kinetics. First, a rotationally constrained tryptophan analogue has fluorescence intensity decay kinetics that can be described by the sum of two exponentials with amplitudes comparable to the relative populations of the two rotational isomers. Second, the multiple exponentials observed for tyrosine-containing model compounds and peptides correlate with the (chi) 1 rotamer populations independently determined by 1H NMR. We now report similar correlations between rotamer populations and fluorescence intensity decay kinetics for a tryptophan analogue of oxytocin. It appears for this compound that either (chi) 2 rotations do not appreciably alter the indole environment, (chi) 2 rotations are rapid enough to average the observed dependence, or only one of two possible (chi) 2 populations is associated with each (chi) 1 rotamer.

Degradation of organic pollutants in/on snow and ice by singlet molecular oxygen (¹O₂*) and an organic triplet excited state.

PubMed

Bower, Jonathan P; Anastasio, Cort

2014-04-01

Singlet molecular oxygen (¹O₂*) can be a significant sink for a variety of electron-rich pollutants in surface waters and atmospheric drops. We recently found that ¹O₂* concentrations are enhanced by up to a factor of 10(4) on illuminated ice compared to in the equivalent liquid solution, suggesting that ¹O₂* could be an important oxidant for pollutants in snow. To examine this, here we study the degradation of three model organic pollutants: furfuryl alcohol (to represent furans), tryptophan (for aromatic amino acids), and bisphenol A (for phenols). Each compound was studied in illuminated aqueous solution and ice containing Rose Bengal (RB, a sensitizer for ¹O₂*) and sodium chloride (to adjust the concentration of total solutes). The RB-mediated loss of each organic compound is enhanced on illuminated ice compared to in solution, by factors of 6400 for furfuryl alcohol, 8300 for tryptophan, and 50 for bisphenol A for ice containing 0.065 mM total solutes. Rates of loss of furfuryl alcohol and tryptophan decrease at a higher total solute concentration, in qualitative agreement with predictions from freezing-point depression. In contrast, the loss of bisphenol A on ice is independent of total solute concentration. Relative to liquid tests, the enhanced loss of tryptophan on ice during control experiments made with deoxygenated solutions and solutions in D₂O show that the triplet excited state of Rose Bengal may also contribute to loss of pollutants on ice.

High-throughput metabolic profiling of diverse green Coffea arabica beans identified tryptophan as a universal discrimination factor for immature beans.

PubMed

Setoyama, Daiki; Iwasa, Keiko; Seta, Harumichi; Shimizu, Hiroaki; Fujimura, Yoshinori; Miura, Daisuke; Wariishi, Hiroyuki; Nagai, Chifumi; Nakahara, Koichi

2013-01-01

The maturity of green coffee beans is the most influential determinant of the quality and flavor of the resultant coffee beverage. However, the chemical compounds that can be used to discriminate the maturity of the beans remain uncharacterized. We herein analyzed four distinct stages of maturity (immature, semi-mature, mature and overripe) of nine different varieties of green Coffea arabica beans hand-harvested from a single experimental field in Hawaii. After developing a high-throughput experimental system for sample preparation and liquid chromatography-mass spectrometry (LC-MS) measurement, we applied metabolic profiling, integrated with chemometric techniques, to explore the relationship between the metabolome and maturity of the sample in a non-biased way. For the multivariate statistical analyses, a partial least square (PLS) regression model was successfully created, which allowed us to accurately predict the maturity of the beans based on the metabolomic information. As a result, tryptophan was identified to be the best contributor to the regression model; the relative MS intensity of tryptophan was higher in immature beans than in those after the semi-mature stages in all arabica varieties investigated, demonstrating a universal discrimination factor for diverse arabica beans. Therefore, typtophan, either alone or together with other metabolites, may be utilized for traders as an assessment standard when purchasing qualified trading green arabica bean products. Furthermore, our results suggest that the tryptophan metabolism may be tightly linked to the development of coffee cherries and/or beans.

Syntheses of halogen derivatives of L-tryptophan, L-tyrosine and L-phenylalanine labeled with hydrogen isotopes.

PubMed

Pająk, Małgorzata; Pałka, Katarzyna; Winnicka, Elżbieta; Kańska, Marianna

2016-01-01

Halogenated, labeled with tritium and doubly with deuterium and tritium, derivatives of L-tryptophan, i.e. 5'-bromo-[2-(3)H]-, 5'-bromo-[2-(2)H/(3)H]-, 5'-fluoro-[2-(3)H]-5'-fluoro-[2-(2)H/(3)H]-, 6'-fluoro-[2-(3)H]-, 6'-fluoro-[2-(2)H/(3)H]-L-tryptophan, as well as, L-tyrosine, i.e. 3'-fluoro-[2-(3)H]-, 3'-fluoro-[2-(2)H/(3)H]-, 3'-chloro-[2-(3)H]-, and 3'-chloro-[2-(2)H/(3)H]-L-tyrosine, and also L-phenylalanine, i.e. 2'-fluoro-[(3S)-(3)H]-, 2'-fluoro-[(3S)-(2)H/(3) H]-, 2'-chloro-[(3S)-(3)H]-, 2'-chloro-[(3S)-(2)H/(3)H]-, 4'-chloro-[(3S)-(3)H]-, and 4'-chloro-[(3S)-(2)H/(3)H]-L-phenylalanine were synthesized using enzymatic methods. Isotopomers of L-tryptophan were synthesized by coupling of halogenated indoles with S-methyl-L-cysteine carried out in deuteriated or tritiated incubation media. Labeled halogenated derivatives of L-tyrosine were obtained by the enzymatically supported exchange between halogenated L-tyrosine and isotopic water. Labeled halogenated isotopologues of L-Phe were synthesized by the enzymatic addition of ammonia to halogenated cinnamic acid. As a source of hydrogen tritiated water (HTO) and heavy water (D2O) with addition of HTO were used. Copyright © 2015 John Wiley & Sons, Ltd.

Characterization of cyclo-Acetoacetyl-L-Tryptophan Dimethylallyltransferase in Cyclopiazonic Acid Biosynthesis: Substrate Promiscuity and Site Directed Mutagenesis Studies

PubMed Central

Liu, Xinyu; Walsh, Christopher T.

2009-01-01

The fungal neurotoxin α-cyclopiazonic acid (CPA), a nanomolar inhibitor of Ca2+-ATPase with a unique pentacyclic indole tetramic acid scaffold is assembled by a three enzyme pathway CpaS, CpaD and CpaO in Aspergillus sp. We recently characterized the first pathway-specific enzyme CpaS, a hybrid two module polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) that generates cyclo-acetoacetyl-L-tryptophan (cAATrp). Here we report the characterization of the second pathway-specific enzyme CpaD that regiospecifically dimethylallylates cAATrp to form β-cyclopiazonic acid. By exploring the tryptophan and tetramate moieties of cAATrp, we demonstrate that CpaD discriminates against free Trp but accepts tryptophan-containing thiohydantoins, diketopiperazines and linear peptides as substrates for C4-prenylation and also acts as regiospecific O-dimethylallyltransferase (DMAT) on a tyrosine-derived tetramic acid. Comparative evaluation of CpaDs from A. oryzae RIB40 and A. flavus NRRL3357 indicated the importance of the N-terminal region for its activity. Sequence alignment of CpaD with eleven homologous fungal Trp-DMATs revealed five regions of conservation suggesting the presense of critical motifs that could be diagonostic for discovering additional Trp-DMATs. Subsequent site-directed mutagenesis studies identified five polar/charged residues and five tyrosine residues within these motifs that are critical for CpaD activity. This motif characerization will enable a gene probe-based approach to discover additional biosynthetic Trp-DMATs. PMID:19877600

Cognitive deficits in a murine model of the eosinophilia-myalgia syndrome: a preliminary report.

PubMed

Middaugh, L D; Nussbaum, R; Ludwicka, A; Bolster, M B; Silver, R M

1996-01-01

The described study was to determine the effects of chronic exposure to 1,1'-ethylidenebis[L-tryptophan] (EBT), a tryptophan contaminant, on cognitive behavior of female C57BL/6 (C57) mice. EBT (also designated as "peak E" or "peak 97") is one of several compounds that are suspect in the eosinophilia-myalgia syndrome (EMS). Groups of female C57 mice (12/group) were injected IP with saline (SAL), tryptophan (TRY), EBT, or an EBT + tryptophan combination (EBT + TRY) over a 6-week period. Previous experiments established that the dosing conditions produce several characteristics of EMS, including dermal inflammation and fibrosis, increased dermal mast cells, and increased levels of quinolinic acid. The mice exposed to EBT + TRY were abnormal during the solution of a Morris water maze problem. First, they had a shorter latency to locate the submerged platform goal during the initial day of training compared to SAL or TRY mice; secondly, they did not show the systematic reduction in latency to locate the platform goal across days of training noted for SAL or TRY mice. These abnormalities occurred in the absence of altered body weight or gross motor activity during the treatment procedure, or in the animal's swim speeds at the time of testing, 3 days after termination of treatment. The results suggest that prolonged exposure to EBT + TRY can alter the reaction to a stressful environment and can alter cognitive behavior.

Development of VHH antibodies against dengue virus type 2 NS1 and comparison with monoclonal antibodies for use in immunological diagnosis.

PubMed

Fatima, Aneela; Wang, Haiying; Kang, Keren; Xia, Liliang; Wang, Ying; Ye, Wei; Wang, Jufang; Wang, Xiaoning

2014-01-01

The possibility of using variable domain heavy-chain antibodies (VHH antibodies) as diagnostic tools for dengue virus (DENV) type 2 NS1 protein was investigated and compared with the use of conventional monoclonal antibodies. After successful expression of DENV type 2 NS1 protein, the genes of VHH antibodies against NS1 protein were biopanned from a non-immune llama library by phage display. VHH antibodies were then expressed and purified from Escherichia coli. Simultaneously, monoclonal antibodies were obtained by the conventional route. Sequence analysis of the VHH antibodies revealed novel and long complementarity determining regions 3 (CDR3). Epitope mapping was performed via a phage display peptide library using purified VHH and monoclonal antibodies as targets. Interestingly, the same region of NS1, which comprises amino acids 224HWPKPHTLW232, was conserved for both kinds of antibodies displaying the consensus motif histidine-tryptophan-tryptophan or tryptophan-proline-tryptophan. The two types of antibodies were used to prepare rapid diagnostic kits based on immunochromatographic assay. The VHH antibody immobilized rapid diagnostic kit showed better sensitivity and specificity than the monoclonal antibody immobilized rapid diagnostic kit, which might be due to the long CDR3 regions of the VHH antibodies and their ability to bind to the pocket and cleft of the targeted antigen. This demonstrates that VHH antibodies are likely to be an option for developing point-of-care tests against DENV infection.

Development of VHH Antibodies against Dengue Virus Type 2 NS1 and Comparison with Monoclonal Antibodies for Use in Immunological Diagnosis

PubMed Central

Fatima, Aneela; Wang, Haiying; Kang, Keren; Xia, Liliang; Wang, Ying; Ye, Wei; Wang, Jufang; Wang, Xiaoning

2014-01-01

The possibility of using variable domain heavy-chain antibodies (VHH antibodies) as diagnostic tools for dengue virus (DENV) type 2 NS1 protein was investigated and compared with the use of conventional monoclonal antibodies. After successful expression of DENV type 2 NS1 protein, the genes of VHH antibodies against NS1 protein were biopanned from a non-immune llama library by phage display. VHH antibodies were then expressed and purified from Escherichia coli. Simultaneously, monoclonal antibodies were obtained by the conventional route. Sequence analysis of the VHH antibodies revealed novel and long complementarity determining regions 3 (CDR3). Epitope mapping was performed via a phage display peptide library using purified VHH and monoclonal antibodies as targets. Interestingly, the same region of NS1, which comprises amino acids 224HWPKPHTLW232, was conserved for both kinds of antibodies displaying the consensus motif histidine-tryptophan-tryptophan or tryptophan-proline-tryptophan. The two types of antibodies were used to prepare rapid diagnostic kits based on immunochromatographic assay. The VHH antibody immobilized rapid diagnostic kit showed better sensitivity and specificity than the monoclonal antibody immobilized rapid diagnostic kit, which might be due to the long CDR3 regions of the VHH antibodies and their ability to bind to the pocket and cleft of the targeted antigen. This demonstrates that VHH antibodies are likely to be an option for developing point-of-care tests against DENV infection. PMID:24751715

Anxiety and depression: individual entities or two sides of the same coin?

PubMed

Nutt, David

2004-01-01

Several factors have led to suggestions that anxiety and depression are actually the same disease: very frequently, they co-exist; there is an overlap of symptoms between the two conditions; a number of similar agents can be used to treat both mental states; the same neurotransmitters are involved in both anxiety and depressive disorders; and stress can predispose both. Selective serotonin reuptake inhibitors (SSRIs) have shown efficacy in a number of neuroses: depression; obsessive-compulsive disorder (OCD) and anxiety disorders (panic disorder [PD], social anxiety disorder [SAD], generalised anxiety disorder and post-traumatic stress disorder). Furthermore, other drugs, for example, tricyclic antidepressants and monoamine oxidase inhibitors, are effective in treating both depression and some anxiety disorders. Yet some drugs are only effective in anxiety, for example, benzodiazepines, and this suggests that the two states are actually different. Despite the broad range of conditions that are treated by SSRIs, a number of differences are clear when SSRIs are used in depressive and anxious states. When used in PD and OCD, the effective dose of the SSRI is often higher than when used to treat depression. Furthermore, SSRIs often work more slowly in patients with anxiety compared with those with depression. In order to assess which serotonergic pathways and mechanisms are involved in these conditions, tryptophan depletion tests can be performed. Tryptophan is the precursor to serotonin (5-HT), so if the SSRI treatment effects are dependent on an increase in synaptic 5-HT levels, depletion will result in a relapse in symptoms. However, if the SSRI treatment works through post-receptor events, then tryptophan depletion will have little effect on the individual's symptoms. In depression, tryptophan depletion induced relapse in patients treated and controlled on SSRIs, but not in those recovered on noradrenergic agents such as desipramine. In some anxious states (PD and SAD), our work has shown that relapse was also experienced following tryptophan depletion, indicating that the SSRIs are acting via increasing 5-HT levels at the synapse in these conditions. However, other studies have found no effect of the tryptophan depletion test. This suggests that in OCD, SSRIs act post-synaptically and therefore have a different mechanism of action in OCD patients compared with depressed patients. In summary, although most SSRIs are effective in the treatment of both depression and anxiety, differences in dose, time to onset of action and, in some cases, mechanism of action are evident when treating the two conditions.

Modulating the pituitary-adrenal response to stress

NASA Technical Reports Server (NTRS)

Vernikos-Danellis, J.

1975-01-01

Serotonin is believed to be a transmitter or regulator of neuronal function. A possible relationship between the pituitary-adrenal secretion of steroids and brain serotonin in the rat was investigated by evaluating the effects of altering brain 5-hydroxy tryptamine (HT) levels on the daily fluctuation of plasma corticosterone and on the response of the pituitary-adrenal system to a stressful or noxious stimulus in the rat. The approach was either to inhibit brain 5-HT synthesis with para-chlorophenyl alanine or to raise its level with precursors such as tryptophan or 5-hydroxy tryptophan.

Low tryptophan diet decreases brain serotonin and alters response to apomorphine

NASA Technical Reports Server (NTRS)

Sahakian, B. J.; Wurtman, R. J.; Barr, J. K.; Millington, W. R.; Chiel, H. J.

1979-01-01

The role of the serotoninergic system in the regulation of apomorphine-induced behavior, a behavior primarily controlled by dopaminergic neurotransmission, was investigated in rats fed on a low tryptophan diet since weaning. It was found that reductions in brain seritonin (5-HT) produced by diet result in decreased stereotypy after apomorphine administration. This indicates that although stereotyped behavior is primarily mediated by dopaminergic mechanisms, it can also be modulated by other neurotransmitter including 5-HT. It was also shown that changes in brain seritonin levels can affect psychomotor stimulant-induced hypothermia.

Applying a mathematical model to estimate the fractional accessibility to quenching of serum albumin by risperidone

NASA Astrophysics Data System (ADS)

Carqueja, Marilena; Cortez, Celia Martins

2014-10-01

In this work we report the results from application of a mathematical model to estimate the fractional accessibility to fluorescence quenching by risperidone in human and bovine sera albumins. Risperidone is an atypical antipsychotic drug used to treat many kinds of psychiatric disorders. Results showed that but the fractional accessibility for trypyophan 134, sub domain 1B, is about 3 times higher than that to tryptophan 212, showing that the primary binding site for risperidone is close to tryptophan 134, in domain IB of BSA.

Changes in River Organic Matter Through Time.

NASA Astrophysics Data System (ADS)

Hudson, N.; Baker, A.; Ward, D.

2006-12-01

Samples of river water from central England were collected during the summer base-flow period. They were analysed for BOD and filtered at 1.2μm and 0.1μm increments to obtain i) the colloidal and dissolved, and ii) dissolved filter sterilized fractions. Each filtered fraction was plated up for microbiological cell counts and the agar plates and water samples were stored under a range of environmental conditions (4° C dark, 11° C light/ dark, 11° C dark, and 20° C dark) for 26 days. Absorbance, fluorescence, pH, conductivity and total organic carbon (TOC) were measured and colony forming units (CFU) counted on days 1, 2, 3, 4, 5, 12, 19 and 26. The fluorescence intensity was recorded for 5 commonly studied regions: protein like fluorescence, indicative of microbial activity, represented by the fluorescent amino acids tyrosine and tryptophan (which has two clear fluorescence regions) and humic and fulvic acids derived from the break down of terrestrial and aquatic plant material. Humic and fulvic-like fluorescence increased in all samples under all storage conditions suggesting that peaks A and C probably include a microbial element, either a product of the living community or as dead cell material in all fraction sizes including <0.1μm. Tryptophan and tyrosine-like fluorescence intensities demonstrated less clear trends which may be reflective of the intrinsic variation in natural samples. Tryptophan-like fluorescence generally decreased or showed minimal change, except in samples exposed to light in which an increase was observed in line with algal growth. A decrease in intensity may relate to the use of the tryptophan-like material as a microbial substrate. The increase in tryptophan-like fluorescence intensity suggests that this fluorescent material is being produced, either by algae, or bacterial activity associated with algal growth. It may also occur as a result of changing water chemistry causing a change in molecular conformation, and resulting fluorescence, as an increase in pH was also observed in these samples. This work illustrates the dynamic character of river organic matter within a timescale and under conditions that are representative of the natural system.

Spectro-temporal characterization of the photoactivation mechanism of two new oxidized cryptochrome/photolyase photoreceptors.

PubMed

Brazard, Johanna; Usman, Anwar; Lacombat, Fabien; Ley, Christian; Martin, Monique M; Plaza, Pascal; Mony, Laetitia; Heijde, Marc; Zabulon, Gérald; Bowler, Chris

2010-04-07

The photoactivation dynamics of two new flavoproteins (OtCPF1 and OtCPF2) of the cryptochrome photolyase family (CPF), belonging to the green alga Ostreococcus tauri , was studied by broadband UV-vis femtosecond absorption spectroscopy. Upon excitation of the protein chromophoric cofactor, flavin adenine dinucleotide in its oxidized form (FAD(ox)), we observed in both cases the ultrafast photoreduction of FAD(ox): in 390 fs for OtCPF1 and 590 fs for OtCPF2. Although such ultrafast electron transfer has already been reported for other flavoproteins and CPF members, the present result is the first demonstration with full spectral characterization of the mechanism. Analysis of the photoproduct spectra allowed identifying tryptophan as the primary electron donor. This residue is found to be oxidized to its protonated radical cation form (WH(*+)), while FAD(ox) is reduced to FAD(*-). Subsequent kinetics were observed in the picosecond and subnanosecond regime, mostly described by a biexponential partial decay of the photoproduct transient signal (9 and 81 ps for OtCPF1, and 13 and 340 ps for OtCPF2), with reduced spectral changes, while a long-lived photoproduct remains in the nanosecond time scale. We interpret these observations within the model proposed by the groups of Brettel and Vos, which describes the photoreduction of FADH(*) within E. coli CPD photolyase (EcCPD) as a sequential electron transfer along a chain of three tryptophan residues, although in that case the rate limiting step was the primary photoreduction in 30 ps. In the present study, excitation of FAD(ox) permitted to reveal the following steps and spectroscopically assign them to the hole-hopping process along the tryptophan chain, accompanied by partial charge recombination at each step. In addition, structural analysis performed by homology modeling allowed us to propose a tentative structure of the relative orientations of FAD and the conserved tryptophan triad. The results of preliminary transient anisotropy measurements performed on OtCPF2 finally showed good compatibility with the oxidation of the distal tryptophan residue (WH(351)) in 340 ps, hence, with the overall Brettel-Vos mechanism.

Introduction of a unique tryptophan residue into various positions of Bacillus licheniformis DnaK.

PubMed

Chen, Bo-En; Lin, Min-Guan; Lo, Huei-Fen; Wang, Tzu-Fan; Chi, Meng-Chun; Lin, Long-Liu

2013-01-01

Site-directed mutagenesis together with biochemical and biophysical techniques were used to probe effects of single-tryptophan-incorporated mutations on a bacterial molecular chaperone, Bacillus licheniformis DnaK (BlDnaK). Specifically, five phenylalanine residues (Phe(120), Phe(174), Phe(186), Phe(378) and Phe(396)) of BlDnaK were individually replaced by single tryptophans, thus creating site-specific probes for the fluorescence analysis of the protein. The steady-state ATPase activity for BlDnaK, F120W, F174W, F186W, F378W, and F396W was determined to be 76.01, 52.82, 25.32, 53.31, 58.84, and 47.53 nmol Pi/min/mg, respectively. Complementation test revealed that the single mutation at codons 120, 186, and 378 of the dnaK gene still allowed an Escherichia coli dnaK756-Ts strain to grow at a stringent temperature of 44°C. Simultaneous addition of co-chaperones and NR-peptide did not synergistically stimulate the ATPase activity of F174W and F396W, and these two proteins were unable to assist the refolding of GdnHCl-denatured luciferase. The heat-induced denaturation of all variants could be fitted adequately to a three-state model, in agreement with the observation for the wild-type protein. By CD spectral analysis, GdnHCl-induced unfolding transition for BlDnaK was 1.51 M corresponding to ΔG(N-U) of 1.69 kcal/mol; however, the transitions for mutant proteins were 1.07-1.55 M equivalent to ΔG(N-U) of 0.94-2.93 kcal/mol. The emission maximum of single-tryptophan-incorporated variants was in the range of 333.2-335.8 nm. Acrylamide quenching analysis showed that the mutant proteins had a dynamic quenching constant of 3.0-4.2 M(-1). Taken together, these results suggest that the molecular properties of BlDnaK have been significantly changed upon the individual replacement of selected phenylalanine residues by tryptophan. Copyright © 2012 Elsevier B.V. All rights reserved.

Picosecond-Resolved Fluorescent Probes at Functionally Distinct Tryptophans within a Thermophilic Alcohol Dehydrogenase: Relationship of Temperature-Dependent Changes in Fluorescence to Catalysis

PubMed Central

2015-01-01

Two single-tryptophan variants were generated in a thermophilic alcohol dehydrogenase with the goal of correlating temperature-dependent changes in local fluorescence with the previously demonstrated catalytic break at ca. 30 °C (Kohen et al., Nature1999, 399, 496). One tryptophan variant, W87in, resides at the active site within van der Waals contact of bound alcohol substrate; the other variant, W167in, is a remote-site surface reporter located >25 Å from the active site. Picosecond-resolved fluorescence measurements were used to analyze fluorescence lifetimes, time-dependent Stokes shifts, and the extent of collisional quenching at Trp87 and Trp167 as a function of temperature. A subnanosecond fluorescence decay rate constant has been detected for W87in that is ascribed to the proximity of the active site Zn2+ and shows a break in behavior at 30 °C. For the remainder of the reported lifetime measurements, there is no detectable break between 10 and 50 °C, in contrast with previously reported hydrogen/deuterium exchange experiments that revealed a temperature-dependent break analogous to catalysis (Liang et al., Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 9556). We conclude that the motions that lead to the rigidification of ht-ADH below 30 °C are likely to be dominated by global processes slower than the picosecond to nanosecond motions measured herein. In the case of collisional quenching of fluorescence by acrylamide, W87in and W167in behave in a similar manner that resembles free tryptophan in water. Stokes shift measurements, by contrast, show distinctive behaviors in which the active-site tryptophan relaxation is highly temperature-dependent, whereas the solvent-exposed tryptophan’s dynamics are temperature-independent. These data are concluded to reflect a significantly constrained environment surrounding the active site Trp87 that both increases the magnitude of the Stokes shift and its temperature-dependence. The results are discussed in the context of spatially distinct differences in enthalpic barriers for protein conformational sampling that may be related to catalysis. PMID:24892947

L-tryptophan-induced electron transport across supported lipid bilayers: an alkyl-chain tilt-angle, and bilayer-symmetry dependence.

PubMed

Sarangi, Nirod Kumar; Patnaik, Archita

2012-12-21

Molecular orientation-dependent electron transport across supported 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers (SLBs) on semiconducting indium tin oxide (ITO) is reported with an aim towards potential nanobiotechnological applications. A bifunctional strategy is adopted to form symmetric and asymmetric bilayers of DPPC that interact with L-tryptophan, and are analyzed by surface manometry and atomic force microscopy. Polarization-dependent real-time Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS) analysis of these SLBs reveals electrostatic, hydrogen-bonding, and cation-π interactions between the polar head groups of the lipid and the indole side chains. Consequently, a molecular tilt arises from the effective interface dipole, facilitating electron transport across the ITO-anchored SLBs in the presence of an internal Fe(CN)(6)(4-/3-) redox probe. The incorporation of tryptophan enhances the voltammetric features of the SLBs. The estimated electron-transfer rate constants for symmetric and asymmetric bilayers (k(s) = 2.0×10(-2) and 2.8×10(-2) s(-1)) across the two-dimensional (2D) ordered DPPC/tryptophan SLBs are higher compared to pure DPPC SLBs (k(s) = 3.2×10(-3) and 3.9×10(-3) s(-1)). In addition, they are molecular tilt-dependent, as it is the case with the standard apparent rate constants k(app)(0), estimated from electrochemical impedance spectroscopy and bipotentiostatic experiments with a Pt ultramicroelectrode. Lower magnitudes of k(s) and k(app)(0) imply that electrochemical reactions across the ITO-SLB electrodes are kinetically limited and consequently governed by electron tunneling across the SLBs. Standard theoretical rate constants (k(th)(0)) accrued upon electron tunneling comply with the potential-independent electron-tunneling coefficient β = 0.15 Å(-1). Insulator-semiconductor transitions moving from a liquid-expanded to a condensed 2D-phase state of the SLBs are noted, adding a new dimension to their transport behavior. These results highlight the role of tryptophan in expediting electron transfer across lipid bilayer membranes in a cellular environment and can provide potential clues towards patterned lipid nanocomposites and devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of tryptophan and indole-3-acetic acid on starch accumulation in the synthetic mutualistic Chlorella sorokiniana-Azospirillum brasilense system under heterotrophic conditions.

PubMed

Palacios, Oskar A; Choix, Francisco J; Bashan, Yoav; de-Bashan, Luz E

2016-06-01

This study measured the relations between tryptophan production, the phytohormone indole-3-acetic acid (IAA) and the metabolism and accumulation of starch during synthetic mutualism between the microalgae Chlorella sorokiniana and the microalgae growth-promoting bacteria Azospirillum brasilense, created by co-immobilization in alginate beads. Experiments used two wild-type A. brasilense strains (Cd and Sp6) and an IAA-attenuated mutant (SpM7918) grown under nitrogen-replete and nitrogen-starved conditions tested under dark, heterotrophic and aerobic growth conditions. Under all incubating conditions, C. sorokiniana, but not A. brasilense, produced tryptophan. A significant correlation between IAA-production by A. brasilense and starch accumulation in C. sorokiniana was found, since the IAA-attenuated mutant was not producing increased starch levels. The highest ADP-glucose pyrophosphorylase (AGPase) activity, starch content and glucose uptake were found during the interaction of A. brasilense wild type strains with the microalgae. When the microalgae were grown alone, they produced only small amounts of starch. Supplementation with synthetic IAA to C. sorokiniana grown alone enhanced the above parameters, but only transiently. Activity of α-amylase decreased under nitrogen-replete conditions, but increased under nitrogen-starved conditions. In summary, this study demonstrated that, during synthetic mutualism, the exchange of tryptophan and IAA between the partners is a mechanism that governs several changes in starch metabolism of C. sorokiniana, yielding an increase in starch content. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Calcium binding to Procambarus clarkii sarcoplasmic calcium binding protein splice variants.

PubMed

Rohrback, Suzanne E; Wheatly, Michele G; Gillen, Christopher M

2015-01-01

Sarcoplasmic calcium binding protein (SCP) is a high-affinity calcium buffering protein expressed in muscle of crayfish and other invertebrates. In previous work, we identified three splice variants of Procambarus clarkii SCP (pcSCP1a, pcSCP1b, and pcSCP1c) that differ in a 37 amino acid region that lies mainly between the 2nd and 3ed EF-hand calcium binding domain. To evaluate the function of the proteins encoded by the pcSCP1 transcripts, we produced recombinant pcSCP1 and used tryptophan fluorescence to characterize calcium binding. Tryptophan fluorescence of pcSCP1a decreased in response to increased calcium, while tryptophan fluorescence of the pcSCP1b and pcSCP1c variants increased. We estimated calcium binding constants and Hill coefficients with two different equations: the standard Hill equation and a modified Hill equation that accounts for contributions from two different tryptophans. The approaches gave similar results. Steady-state calcium binding constants (Kd) ranged from 2.7±0.7×10(-8)M to 5.6±0.1×10(-7)M, consistent with previous work. Variants displayed significantly different apparent calcium affinities, which were decreased in the presence of magnesium. Calcium Kd was lowest for pcSCP1a and highest for pcSCP1c. Site-directed mutagenesis of pcSCP1c residues to the amino acids of pcSCP1b decreased the calcium Kd, identifying residues outside the EF-hand domains that contribute to calcium binding in crayfish SCP. Copyright © 2014 Elsevier Inc. All rights reserved.

Aromatic claw: A new fold with high aromatic content that evades structural prediction: Aromatic Claw

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sachleben, Joseph R.; Adhikari, Aashish N.; Gawlak, Grzegorz

2016-11-10

We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus (PDB ID: 5SYQ). The unusual sequence of this protein has a tryptophan content five times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet withmore » a novel fold that we have termed an Aromatic Claw. As this fold was previously unknown and the sequence unique, we submitted the sequence to CASP10 as a target for blind structural prediction. At the end of the competition, the sequence was classified a hard template based model; the structural relationship between the template and the experimental structure was small and the predictions all failed to predict the structure. CSRosetta was found to predict the secondary structure and its packing; however, it was found that there was little correlation between CSRosetta score and the RMSD between the CSRosetta structure and the NMR determined one. This work demonstrates that even in relatively small proteins, we do not yet have the capacity to accurately predict the fold for all primary sequences. The experimental discovery of new folds helps guide the improvement of structural prediction methods.« less

Neopterin, kynurenine and tryptophan as new biomarkers for early detection of rectal anastomotic leakage.

PubMed

Dusek, Tomas; Orhalmi, Julius; Sotona, Otakar; Krcmova, Lenka Kujovska; Javorska, Lenka; Dolejs, Josef; Paral, Jiri

2018-03-01

At present, there are no strong predictors, nor a useful scoring system, that clearly identifies patients at risk for anastomotic leakage. This study aimed to investigate a new method that assesses this risk by monitoring levels of neopterin, tryptophan, and kynurenine, in bodily fluids. This prospective study included patients who underwent elective rectal resection for carcinoma. The basic condition for inclusion was rectal anastomosis using the double-stapling technique. Preoperative levels of neopterin, tryptophan, kynurenine, and their ratios, were assessed with blood and urine samples. These levels were then monitored for 6 postoperative days in venous blood, urine, and abdominal drainage fluid. A total of 42 patients were enrolled in the study. Thirty-six patients underwent a laparoscopic resection and 6 patients had an open procedure. No differences were found among neopterin, tryptophan, and kynurenine serum levels. However, the groups were observed to have significant differences in the urinary neopterin/creatinine ratio: the preoperative neopterin/creatinine ratio was 139.5 μmol/mol in the group with leakage, vs 114.8 μmol/mol in the group without complications, p = 0.037. The same results were observed during the postoperative period, p = 0.012. Additionally, the group with complications had a higher mean value of neopterin in drainage fluid, p = 0.048. Our study demonstrated that high preoperative levels of urinary neopterin could be interpreted as a risk for anastomotic leakage. Moreover, pathological levels of neopterin in urine and abdominal drainage fluid could be useful for early identification of anastomotic leakage during the postoperative period prior to its clinical development.

Genetic deficiency of indoleamine 2,3-dioxygenase promotes gut microbiota-mediated metabolic health.

PubMed

Laurans, Ludivine; Venteclef, Nicolas; Haddad, Yacine; Chajadine, Mouna; Alzaid, Fawaz; Metghalchi, Sarvenaz; Sovran, Bruno; Denis, Raphael G P; Dairou, Julien; Cardellini, Marina; Moreno-Navarrete, Jose-Maria; Straub, Marjolene; Jegou, Sarah; McQuitty, Claire; Viel, Thomas; Esposito, Bruno; Tavitian, Bertrand; Callebert, Jacques; Luquet, Serge H; Federici, Massimo; Fernandez-Real, José Manuel; Burcelin, Remy; Launay, Jean-Marie; Tedgui, Alain; Mallat, Ziad; Sokol, Harry; Taleb, Soraya

2018-06-25

The association between altered gut microbiota, intestinal permeability, inflammation and cardiometabolic diseases is becoming increasingly clear but remains poorly understood 1,2 . Indoleamine 2,3-dioxygenase is an enzyme induced in many types of immune cells, including macrophages in response to inflammatory stimuli, and catalyzes the degradation of tryptophan along the kynurenine pathway. Indoleamine 2,3-dioxygenase activity is better known for its suppression of effector T cell immunity and its activation of regulatory T cells 3,4 . However, high indoleamine 2,3-dioxygenase activity predicts worse cardiovascular outcome 5-9 and may promote atherosclerosis and vascular inflammation 6 , suggesting a more complex role in chronic inflammatory settings. Indoleamine 2,3-dioxygenase activity is also increased in obesity 10-13 , yet its role in metabolic disease is still unexplored. Here, we show that obesity is associated with an increase of intestinal indoleamine 2,3-dioxygenase activity, which shifts tryptophan metabolism from indole derivative and interleukin-22 production toward kynurenine production. Indoleamine 2,3-dioxygenase deletion or inhibition improves insulin sensitivity, preserves the gut mucosal barrier, decreases endotoxemia and chronic inflammation, and regulates lipid metabolism in liver and adipose tissues. These beneficial effects are due to rewiring of tryptophan metabolism toward a microbiota-dependent production of interleukin-22 and are abrogated after treatment with a neutralizing anti-interleukin-22 antibody. In summary, we identify an unexpected function of indoleamine 2,3-dioxygenase in the fine tuning of intestinal tryptophan metabolism with major consequences on microbiota-dependent control of metabolic disease, which suggests indoleamine 2,3-dioxygenase as a potential therapeutic target.

Stepwise O-Atom Transfer in Heme-Based Tryptophan Dioxygenase: Role of Substrate Ammonium in Epoxide Ring Opening.

PubMed

Shin, Inchul; Ambler, Brett R; Wherritt, Daniel; Griffith, Wendell P; Maldonado, Amanda C; Altman, Ryan A; Liu, Aimin

2018-03-28

Heme-based tryptophan dioxygenases are established immunosuppressive metalloproteins with significant biomedical interest. Here, we synthesized two mechanistic probes to specifically test if the α-amino group of the substrate directly participates in a critical step of the O atom transfer during catalysis in human tryptophan 2,3-dioxygenase (TDO). Substitution of the nitrogen atom of the substrate to a carbon (probe 1) or oxygen (probe 2) slowed the catalytic step following the first O atom transfer such that transferring the second O atom becomes less likely to occur, although the dioxygenated products were observed with both probes. A monooxygenated product was also produced from probe 2 in a significant quantity. Analysis of this new product by HPLC coupled UV-vis spectroscopy, high-resolution mass spectrometry, 1 H NMR, 13 C NMR, HSQC, HMBC, and infrared (IR) spectroscopies concluded that this monooxygenated product is a furoindoline compound derived from an unstable epoxyindole intermediate. These results prove that small molecules can manipulate the stepwise O atom transfer reaction of TDO and provide a showcase for a tunable mechanism by synthetic compounds. The product analysis results corroborate the presence of a substrate-based epoxyindole intermediate during catalysis and provide the first substantial experimental evidence for the involvement of the substrate α-amino group in the epoxide ring-opening step during catalysis. This combined synthetic, biochemical, and biophysical study establishes the catalytic role of the α-amino group of the substrate during the O atom transfer reactions and thus represents a substantial advance to the mechanistic comprehension of the heme-based tryptophan dioxygenases.

Effects of Phenylalanine Substitutions in Gramicidin A on the Kinetics of Channel Formation in Vesicles and Channel Structure in SDS Micelles

PubMed Central

Jordan, J. B.; Easton, P. L.; Hinton, J. F.

2005-01-01

The common occurrence of Trp residues at the aqueous-lipid interface region of transmembrane channels is thought to be indicative of its importance for insertion and stabilization of the channel in membranes. To further investigate the effects of Trp→Phe substitution on the structure and function of the gramicidin channel, four analogs of gramicidin A have been synthesized in which the tryptophan residues at positions 9, 11, 13, and 15 are sequentially replaced with phenylalanine. The three-dimensional structure of each viable analog has been determined using a combination of two-dimensional NMR techniques and distance geometry-simulated annealing structure calculations. These phenylalanine analogs adopt a homodimer motif, consisting of two β6.3 helices joined by six hydrogen bonds at their NH2-termini. The replacement of the tryptophan residues does not have a significant effect on the backbone structure of the channels when compared to native gramicidin A, and only small effects are seen on side-chain conformations. Single-channel conductance measurements have shown that the conductance and lifetime of the channels are significantly affected by the replacement of the tryptophan residues (Wallace, 2000; Becker et al., 1991). The variation in conductance appears to be caused by the sequential removal of a tryptophan dipole, thereby removing the ion-dipole interaction at the channel entrance and at the ion binding site. Channel lifetime variations appear to be related to changing side chain-lipid interactions. This is supported by data relating to transport and incorporation kinetics. PMID:15501932

Effects of phenylalanine substitutions in gramicidin A on the kinetics of channel formation in vesicles and channel structure in SDS micelles.

PubMed

Jordan, J B; Easton, P L; Hinton, J F

2005-01-01

The common occurrence of Trp residues at the aqueous-lipid interface region of transmembrane channels is thought to be indicative of its importance for insertion and stabilization of the channel in membranes. To further investigate the effects of Trp-->Phe substitution on the structure and function of the gramicidin channel, four analogs of gramicidin A have been synthesized in which the tryptophan residues at positions 9, 11, 13, and 15 are sequentially replaced with phenylalanine. The three-dimensional structure of each viable analog has been determined using a combination of two-dimensional NMR techniques and distance geometry-simulated annealing structure calculations. These phenylalanine analogs adopt a homodimer motif, consisting of two beta6.3 helices joined by six hydrogen bonds at their NH2-termini. The replacement of the tryptophan residues does not have a significant effect on the backbone structure of the channels when compared to native gramicidin A, and only small effects are seen on side-chain conformations. Single-channel conductance measurements have shown that the conductance and lifetime of the channels are significantly affected by the replacement of the tryptophan residues (Wallace, 2000; Becker et al., 1991). The variation in conductance appears to be caused by the sequential removal of a tryptophan dipole, thereby removing the ion-dipole interaction at the channel entrance and at the ion binding site. Channel lifetime variations appear to be related to changing side chain-lipid interactions. This is supported by data relating to transport and incorporation kinetics.

Structural basis for the binding of tryptophan-based motifs by δ-COP

PubMed Central

Suckling, Richard J.; Poon, Pak Phi; Travis, Sophie M.; Majoul, Irina V.; Hughson, Frederick M.; Evans, Philip R.; Duden, Rainer; Owen, David J.

2015-01-01

Coatomer consists of two subcomplexes: the membrane-targeting, ADP ribosylation factor 1 (Arf1):GTP-binding βγδζ-COP F-subcomplex, which is related to the adaptor protein (AP) clathrin adaptors, and the cargo-binding αβ’ε-COP B-subcomplex. We present the structure of the C-terminal μ-homology domain of the yeast δ-COP subunit in complex with the WxW motif from its binding partner, the endoplasmic reticulum-localized Dsl1 tether. The motif binds at a site distinct from that used by the homologous AP μ subunits to bind YxxΦ cargo motifs with its two tryptophan residues sitting in compatible pockets. We also show that the Saccharomyces cerevisiae Arf GTPase-activating protein (GAP) homolog Gcs1p uses a related WxxF motif at its extreme C terminus to bind to δ-COP at the same site in the same way. Mutations designed on the basis of the structure in conjunction with isothermal titration calorimetry confirm the mode of binding and show that mammalian δ-COP binds related tryptophan-based motifs such as that from ArfGAP1 in a similar manner. We conclude that δ-COP subunits bind Wxn(1–6)[WF] motifs within unstructured regions of proteins that influence the lifecycle of COPI-coated vesicles; this conclusion is supported by the observation that, in the context of a sensitizing domain deletion in Dsl1p, mutating the tryptophan-based motif-binding site in yeast causes defects in both growth and carboxypeptidase Y trafficking/processing. PMID:26578768

Tryptophan depletion in chronic fatigue syndrome, a pilot cross-over study.

PubMed

The, Gerard K H; Verkes, Robbert J; Fekkes, Durk; Bleijenberg, Gijs; van der Meer, Jos W M; Buitelaar, Jan K

2014-09-16

Chronic fatigue syndrome (CFS) is still an enigmatic disorder. CFS can be regarded as a complex disorder with tremendous impact on lives of CFS-patients. Full recovery without treatment is rare. A somatic explanation for the fatigue is lacking. There is clinical and experimental evidence implicating enhanced serotonergic neurotransmission in CFS. Genetic studies and imaging studies support the hypothesis of upregulated serotonin system in CFS. In line with the hypothesis of an increased serotonergic state in CFS, we performed a randomised clinical trial investigated the effect of 5-HT3 receptor antagonism in CFS. No benefit was found of the 5-HT3 receptor antagonist ondansetron compared to placebo.To further investigate the involvement of serotonin in CFS we performed a placebo controlled cross over pilot study investigating the effect of Acute Tryptophan Depletion. Five female CFS-patients who met the US Center for Disease Control and Prevention criteria for CFS were recruited. There were two test days, one week apart. Each participant received placebo and ATD. To evaluate the efficacy of the ATD procedure tryptophan and the large neutral amino acids were measured. The outcome measures were fatigue severity, concentration and mood states. ATD resulted in a significant plasma tryptophan to large neutral amino acid ratio reduction of 96%. There were no significant differences in fatigue-, depression and concentration between the placebo- and ATD condition. These first five CFS-patients did not respond to the ATD procedure. However, a much larger sample size is needed to draw final conclusions on the hypothesis of an increased serotonergic state in the pathophysiology of CFS. ISRCTN07518149.

Dendritic biomimicry: microenvironmental hydrogen-bonding effects on tryptophan fluorescence.

PubMed

Koenig, S; Müller, L; Smith, D K

2001-03-02

Two series of dendritically modified tryptophan derivatives have been synthesised and their emission spectra measured in a range of different solvents. This paper presents the syntheses of these novel dendritic structures and discusses their emission spectra in terms of both solvent and dendritic effects. In the first series of dendrimers, the NH group of the indole ring is available for hydrogen bonding, whilst in the second series, the indole NH group has been converted to NMe. Direct comparison of the emission wavelengths of analogous NH and NMe derivatives indicates the importance of the Kamlet-Taft solvent beta3 parameter, which reflects the ability of the solvent to accept a hydrogen bond from the NH group, an effect not possible for the NMe series of dendrimers. For the NH dendrimers, the attachment of a dendritic shell to the tryptophan subunit leads to a red shift in emission wavelength. This dendritic effect only operates in non-hydrogen-bonding solvents. For the NMe dendrimers, however, the attachment of a dendritic shell has no effect on the emission spectra of the indole ring. This proves the importance of hydrogen bonding between the branched shell and the indole NH group in causing the dendritic effect. This is the first time a dendritic effect has been unambiguously assigned to individual hydrogen-bonding interactions and indicates that such intramolecular interactions are important in dendrimers, just as they are in proteins. Furthermore, this paper sheds light on the use of tryptophan residues as a probe of the microenvironment within proteins--in particular, it stresses the importance of hydrogen bonds formed by the indole NH group.

Determination of tryptophan derivatives in kynurenine pathway in fermented foods using liquid chromatography tandem mass spectrometry.

PubMed

Yılmaz, Cemile; Gökmen, Vural

2018-03-15

This study aimed to develop an analytical method for the determination of tryptophan and its derivatives in kynurenine pathway using tandem mass spectrometry in various fermented food products (bread, beer, red wine, white cheese, yoghurt, kefir and cocoa powder). The method entails an aqueous extraction and reversed phase chromatographic separation using pentafluorophenyl (PFP) column. It allowed quantitation of low ppb levels of tryptophan and its derivatives in different fermented food matrices. It was found that beer samples were found to contain kynurenine within the range of 28.7±0.7μg/L and 86.3±0.5μg/L. Moreover, dairy products (yoghurt, white cheese and kefir) contained kynurenine ranging from 30.3 to 763.8μg/kg d.w. Though bread samples analyzed did not contain kynurenic acid, beer and red wine samples as yeast-fermented foods were found to contain kynurenic acid. Among foods analyzed, cacao powder had the highest amounts of kynurenic acid (4486.2±165.6μg/kgd.w), which is a neuroprotective compound. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interferon-driven alterations of the host's amino acid metabolism in the pathogenesis of typhoid fever.

PubMed

Blohmke, Christoph J; Darton, Thomas C; Jones, Claire; Suarez, Nicolas M; Waddington, Claire S; Angus, Brian; Zhou, Liqing; Hill, Jennifer; Clare, Simon; Kane, Leanne; Mukhopadhyay, Subhankar; Schreiber, Fernanda; Duque-Correa, Maria A; Wright, James C; Roumeliotis, Theodoros I; Yu, Lu; Choudhary, Jyoti S; Mejias, Asuncion; Ramilo, Octavio; Shanyinde, Milensu; Sztein, Marcelo B; Kingsley, Robert A; Lockhart, Stephen; Levine, Myron M; Lynn, David J; Dougan, Gordon; Pollard, Andrew J

2016-05-30

Enteric fever, caused by Salmonella enterica serovar Typhi, is an important public health problem in resource-limited settings and, despite decades of research, human responses to the infection are poorly understood. In 41 healthy adults experimentally infected with wild-type S. Typhi, we detected significant cytokine responses within 12 h of bacterial ingestion. These early responses did not correlate with subsequent clinical disease outcomes and likely indicate initial host-pathogen interactions in the gut mucosa. In participants developing enteric fever after oral infection, marked transcriptional and cytokine responses during acute disease reflected dominant type I/II interferon signatures, which were significantly associated with bacteremia. Using a murine and macrophage infection model, we validated the pivotal role of this response in the expression of proteins of the host tryptophan metabolism during Salmonella infection. Corresponding alterations in tryptophan catabolites with immunomodulatory properties in serum of participants with typhoid fever confirmed the activity of this pathway, and implicate a central role of host tryptophan metabolism in the pathogenesis of typhoid fever. © 2016 Blohmke et al.

Interferon-driven alterations of the host’s amino acid metabolism in the pathogenesis of typhoid fever

PubMed Central

Jones, Claire; Waddington, Claire S.; Zhou, Liqing; Hill, Jennifer; Clare, Simon; Mukhopadhyay, Subhankar; Schreiber, Fernanda; Roumeliotis, Theodoros I.; Yu, Lu; Ramilo, Octavio; Sztein, Marcelo B.; Kingsley, Robert A.; Levine, Myron M.

2016-01-01

Enteric fever, caused by Salmonella enterica serovar Typhi, is an important public health problem in resource-limited settings and, despite decades of research, human responses to the infection are poorly understood. In 41 healthy adults experimentally infected with wild-type S. Typhi, we detected significant cytokine responses within 12 h of bacterial ingestion. These early responses did not correlate with subsequent clinical disease outcomes and likely indicate initial host–pathogen interactions in the gut mucosa. In participants developing enteric fever after oral infection, marked transcriptional and cytokine responses during acute disease reflected dominant type I/II interferon signatures, which were significantly associated with bacteremia. Using a murine and macrophage infection model, we validated the pivotal role of this response in the expression of proteins of the host tryptophan metabolism during Salmonella infection. Corresponding alterations in tryptophan catabolites with immunomodulatory properties in serum of participants with typhoid fever confirmed the activity of this pathway, and implicate a central role of host tryptophan metabolism in the pathogenesis of typhoid fever. PMID:27217537

Hypothalamic digoxin, hemispheric chemical dominance, and creativity.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2003-04-01

The human hypothalamus produces an endogenous membrane Na(+)-K+ ATPase inhibitor, digoxin, which regulates neuronal transmission. The digoxin status and neurotransmitter patterns were studied in creative and non-creative individuals, as well as in individuals with differing hemispheric dominance, in order to find out the role of cerebral dominance in this respect. The activity of HMG CoA reductase and serum levels of digoxin, magnesium, tryptophan catabolites, and tyrosine catabolites were measured in creative/non-creative individuals, and in individuals with differing hemispheric dominance. In creative individuals there was increased digoxin synthesis, decreased membrane Na(+)-K+ ATPase activity, increased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and decreased tyrosine catabolites (dopamine, noradrenaline, and morphine). The pattern in creative individuals correlated with right hemispheric dominance. In non-creative individuals there was decreased digoxin synthesis, increased membrane Na(+)-K+ ATPase activity, decreased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and increased tyrosine catabolites (dopamine, noradrenaline, and morphine). This pattern in non-creative individuals correlated with that obtained in left hemispheric chemical dominance. Hemispheric chemical dominance and hypothalamic digoxin could regulate the predisposition to creative tendency.

Optimization of Photosensitized Tryptophan Oxidation in the Presence of Dimegin-Polyvinylpyrrolidone-Chitosan Systems.

PubMed

Solovieva, Anna B; Kardumian, Valeria V; Aksenova, Nadezhda A; Belovolova, Lyudmila V; Glushkov, Mikhail V; Bezrukov, Evgeny A; Sukhanov, Roman B; Kotova, Svetlana L; Timashev, Peter S

2018-05-23

By the example of a model process of tryptophan photooxidation in the aqueous medium in the presence of a three-component photosensitizing complex (porphyrin photosensitizer-polyvinylpyrrolidone- chitosan, PPS-PVP-CT) in the temperature range of 20-40 °С, we have demonstrated a possibility of modification of such a process by selecting different molar ratios of the components in the reaction mixture. The actual objective of this selection is the formation of a certain PPS-PVP-CT composition in which PVP macromolecules would coordinate with PPS molecules and at the same time practically block the complex binding of PPS molecules with chitosan macromolecules. Such blocking allows utilization of the bactericidal properties of chitosan to a greater extent, since chitosan is known to depress the PPS photosensitizing activity in PPS-PVP-CT complexes when using those in photodynamic therapy (PDT). The optimal composition of photosensitizing complexes appears to be dependent on the temperature at which the PDT sessions are performed. We have analyzed the correlations of the effective rate constants of tryptophan photooxidation with the photophysical characteristics of the formed complexes.

Tryptophan autofluorescence imaging of neoplasms of the human colon

NASA Astrophysics Data System (ADS)

Banerjee, Bhaskar; Renkoski, Timothy; Graves, Logan R.; Rial, Nathaniel S.; Tsikitis, Vassiliki Liana; Nfonsom, Valentine; Pugh, Judith; Tiwari, Piyush; Gavini, Hemanth; Utzinger, Urs

2012-01-01

Detection of flat neoplasia is a major challenge in colorectal cancer screening, as missed lesions can lead to the development of an unexpected `incident' cancer prior to the subsequent endoscopy. The use of a tryptophan-related autofluorescence has been reported to be increased in murine intestinal dysplasia. The emission spectra of cells isolated from human adenocarcinoma and normal mucosa of the colon were studied and showed markedly greater emission intensity from cancerous cells compared to cells obtained from the surrounding normal mucosa. A proto-type multispectral imaging system optimized for ultraviolet macroscopic imaging of tissue was used to obtain autofluorescence images of surgical specimens of colonic neoplasms and normal mucosa after resection. Fluorescence images did not display the expected greater emission from the tumor as compared to the normal mucosa, most probably due to increased optical absorption and scattering in the tumors. Increased fluorescence intensity in neoplasms was observed however, once fluorescence images were corrected using reflectance images. Tryptophan fluorescence alone may be useful in differentiating normal and cancerous cells, while in tissues its autofluorescence image divided by green reflectance may be useful in displaying neoplasms.

Room temperature fluorescence and phosphorescence study on the interactions of iodide ions with single tryptophan containing serum albumins

NASA Astrophysics Data System (ADS)

Gałęcki, Krystian; Kowalska-Baron, Agnieszka

2016-12-01

In this study, the influence of heavy-atom perturbation, induced by the addition of iodide ions, on the fluorescence and phosphorescence decay parameters of some single tryptophan containing serum albumins isolated from: human (HSA), equine (ESA) and leporine (LSA) has been studied. The obtained results indicated that, there exist two distinct conformations of the proteins with different exposure to the quencher. In addition, the Stern-Volmer plots indicated saturation of iodide ions in the binding region. Therefore, to determine quenching parameter, we proposed alternative quenching model and we have performed a global analysis of each conformer to define the effect of iodide ions in the cavity by determining the value of the association constant. The possible quenching mechanism may be based on long-range through-space interactions between the buried chromophore and quencher in the aqueous phase. The discrepancies of the decay parameters between the albumins studied may be related with the accumulation of positive charge at the main and the back entrance to the Drug Site 1 where tryptophan residue is located.

Kynurenine 3-monooxygenase mediates inhibition of Th17 differentiation via catabolism of endogenous aryl hydrocarbon receptor ligands.

PubMed

Stephens, Geoffrey L; Wang, Qun; Swerdlow, Bonnie; Bhat, Geetha; Kolbeck, Roland; Fung, Michael

2013-07-01

The aryl hydrocarbon receptor (AhR) is a key transcriptional regulator of Th17-cell differentiation. Although endogenous ligands have yet to be identified, evidence suggests that tryptophan metabolites can act as agonists for the AhR. Tryptophan metabolites are abundant in circulation, so we hypothesized that cell intrinsic factors might exist to regulate the exposure of Th17 cells to AhR-dependent activities. Here, we find that Th17 cells preferentially express kynurenine 3-monooxygenase (KMO), which is an enzyme involved in catabolism of the tryptophan metabolite kynurenine. KMO inhibition, either with a specific inhibitor or via siRNA-mediated silencing, markedly increased IL-17 production in vitro, whereas IFN-γ production by Th1 cells was unaffected. Inhibition of KMO significantly exacerbated disease in a Th17-driven model of autoimmune gastritis, suggesting that expression of KMO by Th17 cells serves to limit their continuous exposure to physiological levels of endogenous AhR ligands in vivo. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The role of serotonin in personality inference: tryptophan depletion impairs the identification of neuroticism in the face.

PubMed

Ward, Robert; Sreenivas, Shubha; Read, Judi; Saunders, Kate E A; Rogers, Robert D

2017-07-01

Serotonergic mechanisms mediate the expression of personality traits (such as impulsivity, aggression and anxiety) that are linked to vulnerability to psychological illnesses, and modulate the identification of emotional expressions in the face as well as learning about broader classes of appetitive and aversive signals. Faces with neutral expressions signal a variety of socially relevant information, such that inferences about the big five personality traits, including Neuroticism, Extraversion and Agreeableness, can be accurately made on the basis of emotionally neutral facial photographs. Given the close link between Neuroticism and psychological distress, we investigated the effects of diminished central serotonin activity (achieved by tryptophan depletion) upon the accuracy of 52 healthy (non-clinical) adults' discriminations of personality from facial characteristics. All participants were able to discriminate reliably four of the big five traits. However, the tryptophan-depleted participants were specifically less accurate in discriminating Neuroticism than the matched non-depleted participants. These data suggest that central serotonin activity modulates the identification of not only negative facial emotional expression but also a broader class of signals about personality characteristics linked to psychological distress.

Acid-triggered membrane insertion of Pseudomonas exotoxin A involves an original mechanism based on pH-regulated tryptophan exposure.

PubMed

Méré, Jocelyn; Morlon-Guyot, Juliette; Bonhoure, Anne; Chiche, Laurent; Beaumelle, Bruno

2005-06-03

Exposure to low endosomal pH during internalization of Pseudomonas exotoxin A (PE) triggers membrane insertion of its translocation domain. This process is a prerequisite for PE translocation to the cytosol where it inactivates protein synthesis. Although hydrophobic helices enable membrane insertion of related bacterial toxins such as diphtheria toxin, the PE translocation domain is devoid of hydrophobic stretches and the structural features triggering acid-induced membrane insertion of PE are not known. Here we have identified a molecular device that enables PE membrane insertion. This process is promoted by exposure of a key tryptophan residue. At neutral pH, this Trp is buried in a hydrophobic pocket closed by the smallest alpha-helix of the translocation domain. Upon acidification, protonation of the Asp that is the N-cap residue of the helix leads to its destabilization, enabling Trp side chain insertion into the endosome membrane. This tryptophan-based membrane insertion system is surprisingly similar to the membrane-anchoring mechanism of human annexin-V and could be used by other proteins as well.

Kynurenine Pathway Pathologies: do Nicotinamide and Other Pathway Co-Factors have a Therapeutic Role in Reduction of Symptom Severity, Including Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM)

PubMed Central

Blankfield, Adele

2013-01-01

The definition of dual tryptophan pathways has increased the understanding of the mind-body, body-mind dichotomy. The serotonergic pathway highlights the primary (endogenous) psychiatric disorders. The up-regulation of the kynurenine pathway by physical illnesses can cause neuropathic and immunological disorders1 associated with secondary neuropsychiatric symptoms. Tryptophan and nicotinamide deficiencies fall within the protein energy malnutrition (PEM) spectrum. They can arise if the kynurenine pathway is stressed by primary or secondary inflammatory conditions and the consequent imbalance of available catabolic/anabolic substrates may adversely influence convalescent phase efficiency. The replacement of depleted or reduced NAD+ levels and other cofactors can perhaps improve the clinical management of these disorders. Chronic fatigue syndrome (CFS) and fibromyalgia (FM) appear to meet the criteria of a tryptophan-kynurenine pathway disorder with potential neuroimmunological sequelae. Aspects of some of the putative precipitating factors have been previously outlined.2,3 An analysis of the areas of metabolic dysfunction will focus on future directions for research and management. PMID:23922501

Palladium-Catalyzed Asymmetric Allylic Alkylation of 3-Substituted 1 H-Indoles and Tryptophan Derivatives with Vinylcyclopropanes.

PubMed

Trost, Barry M; Bai, Wen-Ju; Hohn, Christoph; Bai, Yu; Cregg, James J

2018-05-30

Vinylcyclopropanes (VCPs) are known to generate 1,3-dipoles with a palladium catalyst that initially serve as nucleophiles to undergo [3 + 2] cycloadditions with electron-deficient olefins. In this report, we reverse this reactivity and drive the 1,3-dipoles to serve as electrophiles by employing 3-alkylated indoles as nucleophiles. This represents the first use of VCPs for the completely atom-economic functionalization of 3-substituted 1 H-indoles and tryptophan derivatives via a Pd-catalyzed asymmetric allylic alkylation (Pd-AAA). Excellent yields and high chemo-, regio-, and enantioselectivities have been realized, providing various indolenine and indoline products. The method is amenable to gram scale and works efficiently with tryptophan derivatives that contain a diketopiperazine or diketomorpholine ring, allowing us to synthesize mollenine A in a rapid and ligand-controlled fashion. The obtained indolenine products bear an imine, an internal olefin, and a malonate motif, giving multiple sites with diverse reactivities for product diversification. Complicated polycyclic skeletons can be conveniently constructed by leveraging this unique juxtaposition of functional groups.

Effect of acute tryptophan depletion on emotions in individuals with personal and family history of depression following a mood induction.

PubMed

Altman, Sarah E; Shankman, Stewart A; Spring, Bonnie

2010-08-01

Acute tryptophan depletion (ATD) has shown depletion-specific increases in depressed mood and overall depressive symptoms, especially in those with a family history and in remitted patients. However, its effect on a broad range of emotions beyond depressed mood has been inconsistent, and studies have rarely employed a negative mood induction. The present double-blind study administered tryptophan-depleted and taste-matched placebo challenge drinks to individuals with a past diagnosis and family history of depression (i.e. depression-vulnerable subjects) and controls in order to investigate the effect of ATD on positive affect, anxiety, anger and depressed mood following a negative mood induction. Certain aspects of positive affect decreased due to ATD in the depression vulnerables but not in the controls. No differential effects were found on depressed mood and anxiety. A stress-induced blunted hedonic capacity may increase vulnerability to ATD and may be a core emotional abnormality in depression. Additionally, serotonin may have a stronger influence on positive affect than on other depression-related emotions during periods of stress. (c) 2010 S. Karger AG, Basel.

Structural basis for regulation of human calcium-sensing receptor by magnesium ions and an unexpected tryptophan derivative co-agonist.

PubMed

Zhang, Chen; Zhang, Tuo; Zou, Juan; Miller, Cassandra Lynn; Gorkhali, Rakshya; Yang, Jeong-Yeh; Schilmiller, Anthony; Wang, Shuo; Huang, Kenneth; Brown, Edward M; Moremen, Kelley W; Hu, Jian; Yang, Jenny J

2016-05-01

Ca(2+)-sensing receptors (CaSRs) modulate calcium and magnesium homeostasis and many (patho)physiological processes by responding to extracellular stimuli, including divalent cations and amino acids. We report the first crystal structure of the extracellular domain (ECD) of human CaSR bound with Mg(2+) and a tryptophan derivative ligand at 2.1 Å. The structure reveals key determinants for cooperative activation by metal ions and aromatic amino acids. The unexpected tryptophan derivative was bound in the hinge region between two globular ECD subdomains, and represents a novel high-affinity co-agonist of CaSR. The dissection of structure-function relations by mutagenesis, biochemical, and functional studies provides insights into the molecular basis of human diseases arising from CaSR mutations. The data also provide a novel paradigm for understanding the mechanism of CaSR-mediated signaling that is likely shared by the other family C GPCR [G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor] members and can facilitate the development of novel CaSR-based therapeutics.

Identification of a Potent Tryptophan-based TRPM8 Antagonist With in vivo Analgesic Activity.

PubMed

Bertamino, Alessia; Iraci, Nunzio; Ostacolo, Carmine; Ambrosino, Paolo; Musella, Simona; Di Sarno, Veronica; Ciaglia, Tania; Pepe, Giacomo; Sala, Marina; Soldovieri, Maria Virginia; Mosca, Ilaria; Gonzalez-Rodriguez, Sara; Fernández-Carvajal, Asia; Ferrer-Montiel, Antonio; Novellino, Ettore; Taglialatela, Maurizio; Campiglia, Pietro; Gomez-Monterrey, Isabel M

2018-06-25

TRPM8 has been implicated in nociception and pain and is currently regarded as an attractive target for the pharmacological treatment of neuropathic pain syndromes. A series of analogues of N,N'-dibenzyl tryptamine 1, a potent TRPM8 antagonist, were prepared and screened using a fluorescence-based in vitro assay based on menthol-evoked calcium influx in TRPM8 stably-transfected HEK293 cells. The tryptophan derivative 14 was identified as a potent (IC 50 0.2±0.2 nM) and selective TRPM8 antagonist. In vivo, 14 showed significant target coverage in both an icilin-induced WDS (at 1-30 mg/kg s.c.) and oxaliplatin-induced cold allodynia (at 0.1-1 μg s.c.) mice models. Molecular modeling studies identified the putative binding mode of these antagonists, suggesting that they could influence an interaction network between the S1-4 transmembrane segments and the TRP domains of the channel subunits. The tryptophan moiety provides a new pharmacophoric scaffold for the design of highly potent modulators of TRPM8-mediated pain.

Highly selective SERS probe for Hg(II) detection using tryptophan-protected popcorn shaped gold nanoparticles.

PubMed

Senapati, Tapas; Senapati, Dulal; Singh, Anant Kumar; Fan, Zhen; Kanchanapally, Rajashekhar; Ray, Paresh Chandra

2011-10-07

Contamination of the environment with toxic Hg(II) is becoming a huge concern throughout the world now. Driven by the need, this communication reports for the first time a tryptophan protected popcorn shaped gold nanomaterials based SERS probe for rapid, easy and highly selective recognition of Hg(II) ions in the 5 ppb level from aqueous solution, with high sensitivity and selectivity over competing analytes. We demonstrate that our SERS assay is capable of measuring the amount of Hg(II) in alkaline battery. This journal is © The Royal Society of Chemistry 2011

Immunomodulatory constituents from an ascomycete, Microascus tardifaciens.

PubMed

Fujimoto, H; Fujimaki, T; Okuyama, E; Yamazaki, M

1999-10-01

Fractionation guided by the immunosuppressive activity of the defatted AcOEt extract of an Ascomycete, Microascus tardifaciens, afforded eight constituents, questin (emodin 8-O-methylether) (1), rubrocristin (2), 5,7-dihydroxy-4-methylphthalide (3), cladosporin (asperentin) (4), cladosporin 8-O-methylether (5), tradioxopiperazine A [cyclo-L-alanyl-5-isopentenyl-2-(1',1'-dimethylallyl)-L-tryptophan] (6), tradioxopiperazine B [cyclo-L-alanyl-7-isopentenyl-2-(1',1'-dimethylallyl)-L-tryptophan] (7), and asperflavin (8), among which 6 and 7 were new compounds. Compounds 1 and 2 showed considerably high immunosuppressive activity, 6 was moderate and, 3, 4, 5, 7 and 8 showed low activity.

What is the tryptophan kynurenine pathway and why is it important to neurotherapy?

PubMed Central

Davis, Ian

2015-01-01

The kynurenine pathway has received increasing attention as its connection to inflammation, the immune system, and neurological conditions became more apparent. It is the primary route for tryptophan catabolism in the liver and the starting point for the synthesis of nicotinamide adenine dinucleotide in mammals. Dysregulation or overactivation of this pathway can lead to immune system activation and accumulation of potentially neurotoxic compounds. These aspects make the kynurenine pathway a promising target for therapeutic development to treat inflammation and some diseases with neurological aspects, especially in cancer patients undergoing chemotherapy. PMID:26004930

Some metabolic effects of bacterial endotoxins in salmonid fishes

USGS Publications Warehouse

Wedemeyer, G.A.; Ross, A.J.; Smith, L.

1968-01-01

Coho salmon (Oncorhynchus kisutch) and rainbow trout (Salmo gairdneri) were highly resistant to endotoxins from both Escherichia coli and Aeromonas salmonicida (a fish pathogen) at 14 and 18 C.This resistance was investigated with liver tryptophan pyrrolase, liver glycogen depletion in vitro, and the arterial blood pressure as indicators. Liver glycogen depletion was accelerated by both endotoxins, but there was no significant cardiovascular response or effect on liver tryptophan pyrrolase activity. Since the cardiovascular effects of histamine were also limited, it was concluded that the metabolic effects of bacterial endotoxins in salmonids are qualitatively different from those of the higher vertebrates.

5-(2-18F-fluoroethoxy)-L-tryptophan as a substrate of system L transport for tumor imaging by PET.

PubMed

Krämer, Stefanie D; Mu, Linjing; Müller, Adrienne; Keller, Claudia; Kuznetsova, Olga F; Schweinsberg, Christian; Franck, Dominic; Müller, Cristina; Ross, Tobias L; Schibli, Roger; Ametamey, Simon M

2012-03-01

Large neutral l-amino acids are substrates of system L amino acid transporters. The level of one of these, LAT1, is increased in many tumors. Aromatic l-amino acids may also be substrates of aromatic l-amino acid decarboxylase (AADC), the level of which is enhanced in endocrine tumors. Increased amino acid uptake and subsequent decarboxylation result in the intracellular accumulation of the amino acid and its decarboxylation product. (18)F- and (11)C-labeled neutral aromatic amino acids, such as l-3,4-dihydroxy-6-(18)F-fluorophenylalanine ((18)F-FDOPA) and 5-hydroxy-l-[β-(11)C]tryptophan, are thus successfully used in PET to image endocrine tumors. However, 5-hydroxy-l-[β-(11)C]tryptophan has a relatively short physical half-life (20 min). In this work, we evaluated the in vitro and in vivo characteristics of the (18)F-labeled tryptophan analog 5-(2-(18)F-fluoroethoxy)-l-tryptophan ((18)F-l-FEHTP) as a PET probe for tumor imaging. (18)F-l-FEHTP was synthesized by no-carrier-added (18)F fluorination of 5-hydroxy-l-tryptophan. In vitro cell uptake and efflux of (18)F-l-FEHTP and (18)F-FDOPA were studied with NCI-H69 endocrine small cell lung cancer cells, PC-3 pseudoendocrine prostate cancer cells, and MDA-MB-231 exocrine breast cancer cells. Small-animal PET was performed with the respective xenograft-bearing mice. Tissues were analyzed for potential metabolites. (18)F-l-FEHTP specific activity and radiochemical purity were 50-150 GBq/μmol and greater than 95%, respectively. In vitro cell uptake of (18)F-l-FEHTP was between 48% and 113% of added radioactivity per milligram of protein within 60 min at 37°C and was blocked by greater than 95% in all tested cell lines by the LAT1/2 inhibitor 2-amino-2-norboranecarboxylic acid. (18)F-FDOPA uptake ranged from 26% to 53%/mg. PET studies revealed similar xenograft-to-reference tissue ratios for (18)F-l-FEHTP and (18)F-FDOPA at 30-45 min after injection. In contrast to the (18)F-FDOPA PET results, pretreatment with the AADC inhibitor S-carbidopa did not affect the (18)F-l-FEHTP PET results. No decarboxylation products of (18)F-l-FEHTP were detected in the xenograft homogenates. (18)F-l-FEHTP accumulates in endocrine and nonendocrine tumor models via LAT1 transport but is not decarboxylated by AADC. (18)F-l-FEHTP may thus serve as a PET probe for tumor imaging and quantification of tumor LAT1 activity. These findings are of interest in view of the ongoing evaluation of LAT1 substrates and inhibitors for cancer therapy.

Conformational study of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) by tryptophan fluorescence and differential scanning calorimetry.

PubMed

Yin, Shou-Wei; Tang, Chuan-He; Yang, Xiao-Quan; Wen, Qi-Biao

2011-01-12

Fluorescence and differential scanning calorimetry (DSC) were used to study changes in the conformation of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) under various environmental conditions. The possible relationship between fluorescence data and DSC characteristics was also discussed. Tryptophan fluorescence and fluorescence quenching analyses indicated that the tryptophan residues in KPI, exhibiting multiple fluorophores with different accessibilities to acrylamide, are largely buried in the hydrophobic core of the protein matrix, with positively charged side chains close to at least some of the tryptophan residues. GdnHCl was more effective than urea and SDS in denaturing KPI. SDS and urea caused variable red shifts, 2-5 nm, in the emission λ(max), suggesting the conformational compactness of KPI. The result was further supported by DSC characteristics that a discernible endothermic peak was still detected up to 8 M urea or 30 mM SDS, also evidenced by the absence of any shift in emission maximum (λ(max)) at different pH conditions. Marked decreases in T(d) and enthalpy (ΔH) were observed at extreme alkaline and/or acidic pH, whereas the presence of NaCl resulted in higher T(d) and ΔH, along with greater cooperativity of the transition. Decreases in T(d) and ΔH were observed in the presence of protein perturbants, for example, SDS and urea, indicating partial denaturation and decrease in thermal stability. Dithiothreitol and N-ethylmaleimide have a slight effect on the thermal properties of KPI. Interestingly, a close linear relationship between the T(d) (or ΔH) and the λ(max) was observed for KPI in the presence of 0-6 M urea.

The Auxin Biosynthetic TRYPTOPHAN AMINOTRANSFERASE RELATED TaTAR2.1-3A Increases Grain Yield of Wheat.

PubMed

Shao, An; Ma, Wenying; Zhao, Xueqiang; Hu, Mengyun; He, Xue; Teng, Wan; Li, Hui; Tong, Yiping

2017-08-01

Controlling the major auxin biosynthetic pathway to manipulate auxin content could be a target for genetic engineering of crops with desired traits, but little progress had been made because low or high auxin contents often cause developmental inhibition. Here, we performed a genome-wide analysis of bread wheat ( Triticum aestivum ) to identify the Tryptophan Aminotransferase of Arabidopsis1/Tryptophan Aminotransferase-Related (TAA1/TAR) genes that function in the tryptophan-dependent pathway of auxin biosynthesis. Sequence mining together with gene cloning identified 15 TaTAR genes, among which 12 and three genes were phylogenetically close to Arabidopsis ( Arabidopsis thaliana ) AtTAR2 and AtTAR3, respectively. TaTAR2.1 had the most abundant transcripts in the TaTAR2 genes and was expressed mainly in roots and up-regulated by low nitrogen (N) availability. Knockdown of TaTAR2.1 caused vegetative and reproductive deficiencies and impaired lateral root (LR) growth under both high- and low-N conditions. Overexpressing TaTAR2.1-3A in wheat enhanced LR branching, plant height, spike number, grain yield, and aerial N accumulation under different N supply levels. In addition, overexpressing TaTAR2.1-3A in Arabidopsis elevated auxin accumulation in the primary root tip, LR tip, LR primordia, and cotyledon and hypocotyl and increased primary root length, visible LR number, and shoot fresh weight under high- and low-N conditions. Our results indicate that TaTAR2.1 is critical for wheat growth and also shows potential for genetic engineering to reach the aim of improving the grain yield of wheat. © 2017 American Society of Plant Biologists. All Rights Reserved.

Real-time detection of faecally contaminated drinking water with tryptophan-like fluorescence: defining threshold values.

PubMed

Sorensen, James P R; Baker, Andy; Cumberland, Susan A; Lapworth, Dan J; MacDonald, Alan M; Pedley, Steve; Taylor, Richard G; Ward, Jade S T

2018-05-01

We assess the use of fluorescent dissolved organic matter at excitation-emission wavelengths of 280nm and 360nm, termed tryptophan-like fluorescence (TLF), as an indicator of faecally contaminated drinking water. A significant logistic regression model was developed using TLF as a predictor of thermotolerant coliforms (TTCs) using data from groundwater- and surface water-derived drinking water sources in India, Malawi, South Africa and Zambia. A TLF threshold of 1.3ppb dissolved tryptophan was selected to classify TTC contamination. Validation of the TLF threshold indicated a false-negative error rate of 15% and a false-positive error rate of 18%. The threshold was unsuccessful at classifying contaminated sources containing <10 TTC cfu per 100mL, which we consider the current limit of detection. If only sources above this limit were classified, the false-negative error rate was very low at 4%. TLF intensity was very strongly correlated with TTC concentration (ρ s =0.80). A higher threshold of 6.9ppb dissolved tryptophan is proposed to indicate heavily contaminated sources (≥100 TTC cfu per 100mL). Current commercially available fluorimeters are easy-to-use, suitable for use online and in remote environments, require neither reagents nor consumables, and crucially provide an instantaneous reading. TLF measurements are not appreciably impaired by common intereferents, such as pH, turbidity and temperature, within typical natural ranges. The technology is a viable option for the real-time screening of faecally contaminated drinking water globally. Copyright © 2017 Natural Environment Research Council (NERC), as represented by the British Geological Survey (BGS. Published by Elsevier B.V. All rights reserved.

Alpha-tryptophan synthase of Isatis tinctoria: gene cloning and expression.

PubMed

Salvini, M; Boccardi, T M; Sani, E; Bernardi, R; Tozzi, S; Pugliesi, C; Durante, M

2008-07-01

Indole producing reaction is a crux in the regulation of metabolite flow through the pathways and the coordination of primary and secondary product biosynthesis in plants. Indole is yielded transiently from indole-3-glycerol phosphate and immediately condensed with serine to give tryptophan, by the enzyme tryptophan synthase (TS). There is evidence that plant TS, like the bacterial complex, functions as an alpha beta heteromer. In few species, e.g. maize, are known enzymes, related with the TS alpha-subunit (TSA), able to catalyse reaction producing indole, which is free to enter the secondary metabolite pathways. In this contest, we searched for TSA and TSA related genes in Isatis tinctoria, a species producing the natural blue dye indigo. The It-TSA cDNA and the full-length exons/introns genomic region were isolated. The phylogenetic analysis indicates that It-TSA is more closely related to Arabidopsis thaliana At-T14E10.210 TSA (95.7% identity at the amino acid level) with respect to A. thaliana At-T10P11.11 TSA1-like (63%), Zea mays indole-3-glycerol phosphate lyase (54%), Z. mays TSA (53%), and Z. mays indole synthase (50%). The It-TSA cDNA was also able to complement an Escherichia coli trpA mutant. To examine the involvement of It-TSA in the biosynthesis of secondary metabolism compounds, It-TSA expression was tested in seedling grown under different light conditions. Semi-quantitative RT-PCR showed an increase in the steady-state level of It-TSA mRNA, paralleled by an increase of indigo and its precursor isatan B. Our results appear to indicate an involvement for It-TSA in indigo precursor synthesis and/or tryptophan biosynthesis.

Interaction between 5-HTTLPR genotype and cognitive stress vulnerability on sleep quality: effects of sub-chronic tryptophan administration.

PubMed

van Dalfsen, Jens H; Markus, C Rob

2015-02-02

Abundant evidence suggests that allelic variation in the serotonin transporter-linked polymorphic region (5-HTTLPR) influences susceptibility to stress and its affective consequences due to brain serotonergic vulnerability. Based on recent assumptions, the present study examined whether the 5-HTTLPR genotype may also interact with a vulnerability to chronic stress experience (conceptualized by trait neuroticism) in order to influence sleep quality and, additionally, whether this is influenced by brain serotonergic manipulations. In a well-balanced experimental design, homozygous S-allele (n = 57) and L-allele (n = 54) genotypes with high and low chronic stress vulnerability (neuroticism) were first assessed for general past sleep quality during a month before onset of the experiment. Then subjects were assessed for sleep quality following 7 days of tryptophan (3.0g/day) or placebo intake. Although high neuroticism was significantly related to a higher frequency of stressful life events and daily hassles, it did not interact with the 5-HTTLPR genotype on general past sleep quality. However, as expected, a 7 day period of tryptophan administration was exclusively associated with better sleep quality scores in the S'/S' genotype with high trait neuroticism. Current findings suggest that 5-HTTLPR does not directly interact with stress vulnerability in order to influence sleep quality. Instead, based on current and previous findings, it is suggested that the S'/S' 5-HTTLPR genotype promotes the risk for stress-related sleep disturbances because of an increased susceptibility to the depressogenic consequences of stress. Accordingly, by way of reducing depressive symptomatology, tryptophan augmentation may particularly improve sleep quality in stress-vulnerable individuals carrying the 5-HTTLPR S-allele. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Real-time Measurements of Amino Acid and Protein Hydroperoxides Using Coumarin Boronic Acid*

PubMed Central

Michalski, Radoslaw; Zielonka, Jacek; Gapys, Ewa; Marcinek, Andrzej; Joseph, Joy; Kalyanaraman, Balaraman

2014-01-01

Hydroperoxides of amino acid and amino acid residues (tyrosine, cysteine, tryptophan, and histidine) in proteins are formed during oxidative modification induced by reactive oxygen species. Amino acid hydroperoxides are unstable intermediates that can further propagate oxidative damage in proteins. The existing assays (oxidation of ferrous cation and iodometric assays) cannot be used in real-time measurements. In this study, we show that the profluorescent coumarin boronic acid (CBA) probe reacts with amino acid and protein hydroperoxides to form the corresponding fluorescent product, 7-hydroxycoumarin. 7-Hydroxycoumarin formation was catalase-independent. Based on this observation, we have developed a fluorometric, real-time assay that is adapted to a multiwell plate format. This is the first report showing real-time monitoring of amino acid and protein hydroperoxides using the CBA-based assay. This approach was used to detect protein hydroperoxides in cell lysates obtained from macrophages exposed to visible light and photosensitizer (rose bengal). We also measured the rate constants for the reaction between amino acid hydroperoxides (tyrosyl, tryptophan, and histidine hydroperoxides) and CBA, and these values (7–23 m−1 s−1) were significantly higher than that measured for H2O2 (1.5 m−1 s−1). Using the CBA-based competition kinetics approach, the rate constants for amino acid hydroperoxides with ebselen, a glutathione peroxidase mimic, were also determined, and the values were within the range of 1.1–1.5 × 103 m−1 s−1. Both ebselen and boronates may be used as small molecule scavengers of amino acid and protein hydroperoxides. Here we also show formation of tryptophan hydroperoxide from tryptophan exposed to co-generated fluxes of nitric oxide and superoxide. This observation reveals a new mechanism for amino acid and protein hydroperoxide formation in biological systems. PMID:24928516

Cloning and characterization of indole synthase (INS) and a putative tryptophan synthase α-subunit (TSA) genes from Polygonum tinctorium.

PubMed

Jin, Zhehao; Kim, Jin-Hee; Park, Sang Un; Kim, Soo-Un

2016-12-01

Two cDNAs for indole-3-glycerol phosphate lyase homolog were cloned from Polygonum tinctorium. One encoded cytosolic indole synthase possibly in indigoid synthesis, whereas the other encoded a putative tryptophan synthase α-subunit. Indigo is an old natural blue dye produced by plants such as Polygonum tinctorium. Key step in plant indigoid biosynthesis is production of indole by indole-3-glycerol phosphate lyase (IGL). Two tryptophan synthase α-subunit (TSA) homologs, PtIGL-short and -long, were isolated by RACE PCR from P. tinctorium. The genome of the plant contained two genes coding for IGL. The short and the long forms, respectively, encoded 273 and 316 amino acid residue-long proteins. The short form complemented E. coli ΔtnaA ΔtrpA mutant on tryptophan-depleted agar plate signifying production of free indole, and thus was named indole synthase gene (PtINS). The long form, either intact or without the transit peptide sequence, did not complement the mutant and was tentatively named PtTSA. PtTSA was delivered into chloroplast as predicted by 42-residue-long targeting sequence, whereas PtINS was localized in cytosol. Genomic structure analysis suggested that a TSA duplicate acquired splicing sites during the course of evolution toward PtINS so that the targeting sequence-containing pre-mRNA segment was deleted as an intron. PtINS had about two to fivefolds higher transcript level than that of PtTSA, and treatment of 2,1,3-benzothiadiazole caused the relative transcript level of PtINS over PtTSA was significantly enhanced in the plant. The results indicate participation of PtINS in indigoid production.

Aging leads to prolonged duration of inflammation-induced depression-like behavior caused by Bacillus Calmette-Guérin.

PubMed

Kelley, Keith W; O'Connor, Jason C; Lawson, Marcus A; Dantzer, Robert; Rodriguez-Zas, Sandra L; McCusker, Robert H

2013-08-01

Geriatric depression is a costly health issue, but little is known about its physiological underpinnings. Systemic inflammation sensitizes the innate immune system of aged animals and humans, but it is unknown if chronic, low-grade infections affect the duration of depressive-like behaviors. In this report, we infected adult (4-6 months) and aged (20-24 months) Balb/c mice with an attenuated strain of Mycobacterium bovis, Bacillus Calmette-Guérin (BCG), to induce a chronic infection. We then measured depression-like behaviors that have construct, face and predictive validity for human inflammation-associated clinical depression. Exposure to BCG caused acute sickness responses in both adult and aged mice. However, sickness behavior was prolonged in aged mice, as assessed by both locomotor and rearing activity. Two measures of depression-like behavior, which were tests involving sucrose preference and tail suspension, both showed that adult mice displayed depression-like behaviors at one day and seven days after exposure to BCG. However, aged mice continued to express both of these depression-like behaviors at three weeks following infection. Infection with BCG caused an increase in tryptophan catabolism, as evidenced by a significant rise in the plasma kynurenine/tryptophan ratio that peaked at 7 days post-infection. In aged mice, greater tryptophan catabolism persisted longer and remained elevated at 21 days post-infection. This finding is consistent with the prolonged duration of depression-like behaviors in aged mice. These are the first data using a chronic infection model to establish that recovery from inflammation-induced depression-like behavior and tryptophan catabolism are prolonged in aged animals. Copyright © 2013 Elsevier Inc. All rights reserved.

Understanding aquatic microbial processes using EEM's and in-situ fluorescence sensors

NASA Astrophysics Data System (ADS)

Fox, Bethany; Attridge, John; Rushworth, Cathy; Cox, Tim; Anesio, Alexandre; Reynolds, Darren

2015-04-01

The diverse origin of dissolved organic matter (DOM) in aquatic systems is well documented within the literature. Previous literature indicates that coloured dissolved organic matter (CDOM) is, in part, transformed by aquatic microbial processes, and that dissolved organic material derived from a microbial origin exhibits tryptophan-like fluorescence. However, this phenomenon is not fully understood and very little data is available within the current literature. The overall aim of our work is to reveal the microbial-CDOM interactions that give rise to the observed tryptophan-like fluorescence. The work reported here investigates the microbial processes that occur within freshwater aquatic samples, as defined by the biochemical oxygen demand (BOD) test, as a function of the T1 peak (λex/em 280/330-370 nm). A series of standard water samples were prepared using glucose, glutamic acid, BOD dilution water and a bacterial seed (Cole-Parmer BOD microbe capsules). Samples were spiked with CDOM (derived from an environmental water body) and subjected to time resolved BOD analysis and as excitation-emission fluorescence spectroscopy. All EEM spectral data was interrogated using parallel factor analysis (PARAFAC) in an attempt to determine the presence and dominance (relative intensities) of the CDOM-related and T1-related fluorophores within the samples. In-situ fluorescence sensors (Chelsea Technologies Group Ltd.) were also used to monitor the T1 fluorescence peak (UviLux Tryptophan) and the CDOM fluorescence peak (UviLux CDOM) during experiments. Tryptophan-like fluorescence was observed (albeit transient) in both spiked and un-spiked standard water samples. By furthering our understanding of aquatic organic matter fluorescence, its origin, transformation, fate and interaction with aquatic microbiological processes, we aim to inform the design of a new generation in-situ fluorescence sensor for the monitoring of aquatic ecosystem health.

A Diverging DOS Strategy Using an Allene-Containing Tryptophan Scaffold and a Library Design that Maximizes Biologically Relevant Chemical Space While Minimizing the Number of Compounds

PubMed Central

Painter, Thomas O.; Wang, Lirong; Majumder, Supriyo; Xie, Xiang-Qun; Brummond, Kay M.

2011-01-01

A diverging diversity-oriented synthesis (DOS) strategy using an allene-containing tryptophan as a key starting material was investigated. An allene-yne substituted derivative of tryptophan 12 gave indolylmethylazabicyclooctadiene 17 when subjected to a microwave-assisted allenic [2 + 2] cycloaddition reaction. This same tryptophan-derived precursor afforded an indolylmethyldihydrocyclopentapyridinone 14 when subjected to a rhodium(I)-catalyzed cyclocarbonylation reaction and an indolylmethylpyrrolidinocyclopentenones 16 when reacted with molybdenum hexacarbonyl. Construction of allenic tetrahydro-β-carboline scaffolds via a Pictet-Spengler reaction and subsequent silver(I)-catalyzed cycloisomerization afforded tetrahydroindolizinoindoles (21). Attachment of allene and alkyne groups to the tetrahydro-β-carboline followed by a microwave-assisted allenic [2 + 2] cycloaddition reaction provided tetrahydrocyclobutaindoloquinolizinones 24 and the tetrahydrocyclopentenone indolizinoindolone 26 when reacted with molybdenum hexacarbonyl. These six scaffolds were used as a template for the construction of a virtual library of 11,748 compounds employing 44 indoles, 12 aldehydes, and 51 alkynes. Diversity analyses using a combination of cell-based chemistry space computations using BCUT (Burden (B) CAS (C) Pearlman at the University of Texas (UT)) metrics and Tanimoto coefficient (Tc) similarity calculations using two-dimensional (2D) fingerprints showed that the compounds in the virtual library occupied new chemical space when compared to the 327,000 compounds in the molecular libraries small molecule repository (MLSMR). A subset of fifty-three compounds was identified from the virtual library using the DVS package of Sybyl 8.0; this subset represents the most diverse compounds within the chemical space defined by these compounds and will be synthesized and screened for biological activity. PMID:21332123

On the possible quantum role of serotonin in consciousness.

PubMed

Tonello, Lucio; Cocchi, Massimo; Gabrielli, Fabio; Tuszynski, Jack A

2015-09-01

Cell membrane's fatty acids (FAs) have been carefully investigated in neurons and platelets in order to study a possible connection to psychopathologies. An important link between the FA distribution and membrane dynamics appears to emerge with the cytoskeleton dynamics. Microtubules (MTs) in particular have been implicated in some recent quantum consciousness models and analyses. The recently proposed quantum model of Craddock et al. (2014) states that MTs possess structural and functional characteristics that are consistent with collective quantum coherent excitations in the aromatic groups of their tryptophan residues. These excitations are consistent with a clocking mechanism on a sub-nanosecond scale. This mechanism and analogous phenomena in light-harvesting complexes in plants and bacteria, are induced by photons and have been touted as evidence of quantum processes in biology. A possible source of intra-cellular photons could be membrane lipid peroxidation processes, so the FA profile could then be linked to the bio-photon emission. The model presented here suggests new ways to understand the role serotonin plays in relation to FAs. In plants, tryptophan conversion of light to exciton energy can participate in the directional orientation of leaves toward sunlight. Since serotonin is structurally similar to tryptophan, in the human brain, neurons could use tryptophan to capture photons and also use serotonin to initiate movement toward the source of light. Hence, we postulate two possible new roles for serotonin: (1) as an antioxidant, in order to counter-balance the oxidative effect of FAs, and (2) to participate in quantum interactions with MTs, in the same way as anesthetics and psychoactive compounds have been recently shown to act. In this latter case, the FA profile could provide an indirect measure of serotonin levels.

Tryptophan Hydroxylase 2 Gene Polymorphism in Anxiety and Depressive Disorder in Kashmiri Population

PubMed Central

Shoib, Sheikh; Shah, Tabindah; Mushtaq, Sahil

2014-01-01

Background: The gene of tryptophan hydroxylase is widely recognized as a major candidate gene in many psychiatric disorders. However, no study has been done which investigates tryptophan hydroxylase 2 gene polymorphism in anxiety and depressive disorders in Kashmiri population (India). Objectives: To study tryptophan hydroxylase 2 (TPH2) C 11993 A gene polymorphism in anxiety and depressive disorders. Method: Sixty patients of depression disorder, 60 patients of anxiety disorder and 40 unrelated healthy volunteers (control) were studied in a case control design. Polymorphism was determined using polymerase chain reaction (PCR) and agarose gel electrophoresis after digestion with HAP II enzyme. Genotypes and allele frequencies were compared using Chi-square tests, Fischer’s exact test, odds ratio, 95% confidence interval (C.I) and p-value of <0.05 was considered to be statistical significant. Results: The mean age ± SD of anxiety, depression and control group was 32.73±10.99, 32.20±10 and 29.75±10.12 respectively and the difference was found to be statistically non significant (p=0.349).The mean HAM-A (Hamilton rating scale for anxiety) score and HAM-D (Hamilton rating scale for depression) score was high in both groups (anxiety and depression) and found to be statistically significant (p=0.001).Depression group had AA genotype (55.2%) than control (37.5%) and was found to be statistically non significant (p=0.890).Comparison of allelic frequency revealed no association of A allele in anxiety group (76.67%) compared with control (75.5%) and was found to be statistically non significant (p= 0.866), OR 1.09 (0.56-2.11). Conclusion: TPH2C 11993 A gene was not found to be associated with major depressive disorder (MDD) and anxiety disorder in Kashmiri population. PMID:25121048

Marker-assisted introgression of opaque2 allele for rapid conversion of elite hybrids into quality protein maize.

PubMed

Hossain, Firoz; Muthusamy, Vignesh; Pandey, Neha; Vishwakarma, Ashish K; Baveja, Aanchal; Zunjare, Rajkumar U; Thirunavukkarasu, Nepolean; Saha, Supradip; Manjaiah, Kanchikeri M Manjaiah; Prasanna, Boddupalli M; Gupta, Hari S

2018-03-01

Maize is a valuable source of food and feed worldwide. Maize endosperm protein is, however nutritionally poor due to the reduced levels of two essential amino acids, lysine and tryptophan. In this study, recessive opaque2 (o2) allele that confers enhanced endosperm lysine and tryptophan, was introgressed using marker-assisted backcross breeding into three normal inbred lines (HKI323, HKI1105 and HKI1128). These are the parental lines of three popular medium-maturing single cross hybrids (HM4, HM8 and HM9) in India. Gene-based simple sequence repeat (SSR) markers (umc1066 and phi057) were successfully deployed for introgression of o2 allele. Background selection using genome-based SSRs helped in recovering > 96% of recurrent parent genome. The newly developed quality protein maize (QPM) inbreds showed modified kernels (25-50% opaqueness) coupled with high degree of phenotypic resemblance to the respective recipient lines, including grain yield. In addition, endosperm protein quality showed increased lysine and tryptophan in the inbreds to the range of 52-95% and 47-118%, respectively. The reconstituted QPM hybrids recorded significant enhancement of endosperm lysine (48-74%) and tryptophan (55-100%) in the endosperm. The QPM hybrids exhibited high phenotypic similarity with the original hybrids for morphological and yield contributing traits along with responses to some major diseases like turcicum leaf blight and maydis leaf blight. The grain yield of QPM hybrids was at par with their original versions under multilocation testing. These elite, high-yielding QPM hybrids with improved protein quality have been released and notified for commercial cultivation, and hold significant promise for improving nutritional security.

Quenching interaction of BSA with DTAB is dynamic in nature: A spectroscopic insight

NASA Astrophysics Data System (ADS)

Das, Nirmal Kumar; Pawar, Lavanya; Kumar, Naveen; Mukherjee, Saptarshi

2015-08-01

The role of electrostatic interactions between the protein, Bovine Serum Albumin (BSA) and the cationic surfactant, dodecyltrimethylammonium bromide (DTAB) has been substantiated using spectroscopic approaches. The primary mechanism of fluorescence quenching of the tryptophan of BSA is most probably dynamic in nature as the complex formation resulting in a protein-surfactant assembly is not very spontaneous. The weak interaction buries the tryptophan amino acid residue inside the protein scaffolds which have been quantitatively proved by our acrylamide quenching studies. The loss in the secondary structure of the protein as a result of interaction with DTAB has been elucidated by CD spectroscopy.

Temporary anion states of selected amino acids

NASA Astrophysics Data System (ADS)

Aflatooni, K.; Hitt, B.; Gallup, G. A.; Burrow, P. D.

2001-10-01

Vertical attachment energies for the formation of low-lying temporary anion states of glycine, alanine, phenylalanine, tryptophan, and proline in the gas phase are reported using electron transmission spectroscopy. Electron attachment into the empty π* orbital of the -COOH group was observed in all the compounds. Temporary anion states associated with the side groups in phenylalanine and tryptophan are found to be stabilized with respect to those in the reference compounds toluene and indole, respectively, by approximately 0.2 eV. We attribute this to electrostatic effects and explore, using simple theoretical models, the extent to which such anion states could be further stabilized if these amino acids were in zwitterionic form.

Luminescence diagnostics of conformational changes of the Hsp70 protein in the course of thermal denaturation

NASA Astrophysics Data System (ADS)

Bukina, M. N.; Bakulev, V. M.; Barmasov, A. V.; Zhakhov, A. V.; Ishchenko, A. M.

2015-06-01

The spectral luminescence properties of aqueous solutions of the Hsp70 protein are studied, the dependence of the luminescence spectrum on the excitation wavelength is revealed, and the temperature dependence of luminescence intensity of tyrosine and tryptophan residues in the temperature interval of 20-80° C is analyzed. The luminescence method is used to determine temperature interval (42-57° C) in which protein melting takes place. An increase in the fluorescence quantum yield of tryptophan and the bathochromic shift of the emission spectrum of denatured Hsp70 prove that transition takes place of tryptophanyls to the surface of the protein molecule.

Effect of Tryptophan and Asparagine Structure on the Enthalpic Characteristics of Their Dissolution in Aqueous Solutions of Sodium Dodecyl Sulfate

NASA Astrophysics Data System (ADS)

Mezhevoi, I. N.; Badelin, V. G.; Tyunina, E. Yu.; Kamkina, S. V.

2018-03-01

The integral enthalpies of dissolution of L-tryptophan and L-asparagine in aqueous solutions of sodium dodecyl sulfate (surfactant) at surfactant concentrations of up to 0.05 mol/kg of the solvent are determined and estimated calorimetrically. Standard values of the enthalpies of dissolution and transfer of amino acids from water to a mixed solvent are calculated. The calculated enthalpy coefficients of pair interactions between amino acids and surfactant molecules have positive values. Hydrophobic interactions between amino acids and surfactants have the dominant effect on the enthalpy characteristics of the interaction in a three-component solution.

Tryptophan: the key to boosting brain serotonin synthesis in depressive illness.

PubMed

Badawy, Abdulla A-B

2013-10-01

It has been proposed that focusing on brain serotonin synthesis can advance antidepressant drug development. Biochemical aspects of the serotonin deficiency in major depressive disorder (MDD) are discussed here in detail. The deficiency is caused by a decreased availability of the serotonin precursor tryptophan (Trp) to the brain. This decrease is caused by accelerated Trp degradation, most likely induced by enhancement of the hepatic enzyme tryptophan 2,3-dioxygenase (TDO) by glucocorticoids and/or catecholamines. Induction of the extrahepatic Trp-degrading enzyme indolylamine 2,3-dioxygenase (IDO) by the modest immune activation in MDD has not been demonstrated and, if it occurs, is unlikely to make a significant contribution. Liver TDO appears to be a target of many antidepressants, the mood stabilisers Li(+) and carbamazepine and possibly other adjuncts to antidepressant therapy. The poor, variable and modest antidepressant efficacy of Trp is due to accelerated hepatic Trp degradation, and efficacy can be restored or enhanced by combination with antidepressants or other existing or new TDO inhibitors. Enhancing Trp availability to the brain is thus the key to normalisation of serotonin synthesis and could form the basis for future antidepressant drug development.

Hypothalamic digoxin, hemispheric chemical dominance, and eating behavior.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2003-08-01

The isoprenoid pathway produces an endogenous membrane Na+-K+ ATPase inhibitor, digoxin, which can regulate neurotransmitter and amino acid transport. Digoxin synthesis and neurotransmitter patterns were assessed in eating disorders. The patterns were compared in those with right hemispheric and left hemispheric dominance. The serum HMG CoA reductase activity, RBC membrane Na+-K+ ATPase activity, serum digoxin, magnesium, tryptophan catabolites (serotonin, quinolinic acid, strychnine, and nicotine), and tyrosine catabolites (morphine, dopamine, and noradrenaline) were measured in anorexia nervosa, bulimia nervosa, right hemispheric dominant, left hemispheric dominant, and bihemispheric dominant individuals. Digoxin synthesis was increased with upregulated tryptophan catabolism and downregulated tyrosine catabolism in those with anorexia nervosa and right hemispheric chemical dominance. Digoxin synthesis was reduced with downregulated tryptophan catabolism and upregulated tyrosine catabolism in those with bulimia nervosa and left hemispheric chemical dominance. The membrane Na+-K+ ATPase activity and serum magnesium were decreased in anorexia nervosa and right hemispheric chemical dominance while they were increased in bulimia nervosa and left hemispheric chemical dominance. Hypothalamic digoxin and hemispheric chemical dominance play a central role in the regulation of eating behavior. Anorexia nervosa represents the right hemispheric chemically dominant/hyperdigoxinemic state and bulimia nervosa the left hemispheric chemically dominant/hypodigoxinemic state.

Anthranilate synthase subunit organization in Chromobacterium violaceum.

PubMed

Carminatti, C A; Oliveira, I L; Recouvreux, D O S; Antônio, R V; Porto, L M

2008-09-16

Tryptophan is an aromatic amino acid used for protein synthesis and cellular growth. Chromobacterium violaceum ATCC 12472 uses two tryptophan molecules to synthesize violacein, a secondary metabolite of pharmacological interest. The genome analysis of this bacterium revealed that the genes trpA-F and pabA-B encode the enzymes of the tryptophan pathway in which the first reaction is the conversion of chorismate to anthranilate by anthranilate synthase (AS), an enzyme complex. In the present study, the organization and structure of AS protein subunits from C. violaceum were analyzed using bioinformatics tools available on the Web. We showed by calculating molecular masses that AS in C. violaceum is composed of alpha (TrpE) and beta (PabA) subunits. This is in agreement with values determined experimentally. Catalytic and regulatory sites of the AS subunits were identified. The TrpE and PabA subunits contribute to the catalytic site while the TrpE subunit is involved in the allosteric site. Protein models for the TrpE and PabA subunits were built by restraint-based homology modeling using AS enzyme, chains A and B, from Salmonella typhimurium (PDB ID 1I1Q).

Amino acid composition of some Mexican foods.

PubMed

Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor

2005-06-01

Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.

Overlapping the Tryptophan Catabolite (TRYCAT) and Melatoninergic Pathways in Alzheimer's Disease.

PubMed

Maes, Michael; Anderson, George

2016-01-01

Activation of the trptophan catabolite (TRYCAT) pathways by oxidative and nitrosative stress and proinflammatory cytokine-driven indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) leads to the synthesis of a number of neuroregulatory TRYCATs, such as kynurenic acid and quinolinic acid. Such TRYCATs have significant impacts on neuronal functioning and survival contributing to the changes seen in Alzheimer's disease (AD), including in its association with depression as well as alterations in the reactivity of immune and glia cells. By decreasing the availability of tryptophan for serotonin synthesis, such IDO and TDO-driven TRYCATs, also decrease the availability of serotonin for N-acetylserotonin (NAS) and melatonin synthesis. The loss of NAS and melatonin has significant consequences for the etiology, course and treatment of AD, including via interactions with altered TRYCATs, but also by changing the levels of trophic support and modulating the patterning of immune activity. In this review, we look at how such interactions of the TRYCAT and melatoninergic pathways link a plethora of previously diffuse data in AD as well as the treatment implications and future research directions that such data would suggest.

Simultaneous and sensitive determination of ascorbic acid, dopamine, uric acid, and tryptophan with silver nanoparticles-decorated reduced graphene oxide modified electrode.

PubMed

Kaur, Balwinder; Pandiyan, Thangarasu; Satpati, Biswarup; Srivastava, Rajendra

2013-11-01

In this paper, we report the synthesis of silver nanoparticle-decorated reduced graphene oxide composite (AgNPs/rGO) by heating the mixture of graphene oxide and silver nitrate aqueous solution in the presence of sodium hydroxide. This material was characterized by means of X-ray diffraction, UV-vis spectroscopy, and transmission electron microscopy. AgNPs/rGO based electrochemical sensor was fabricated for the simultaneous determination of ascorbic acid, dopamine, uric acid, and tryptophan. Electrochemical studies were carried out by using cyclic voltammetry, linear sweep voltammetry, and chronoamperometry. AgNPs/rGO modified electrode exhibited excellent electrocatalytic activity, stability, sensitivity, and selectivity with well-separated oxidation peaks toward ascorbic acid, dopamine, uric acid, and tryptophan in the simultaneous determination of their quaternary mixture. The analytical performance of this material as a chemical sensor was demonstrated for the determination of ascorbic acid and dopamine in commercial pharmaceutical samples such as vitamin C tablets and dopamine injections, respectively. The applicability of this sensor was also extended in the determination of uric acid in human urine samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Water-Tryptophan Interactions: Lone-pair⋅⋅⋅π or O-H⋅⋅⋅π? Molecular Dynamics Simulations of β-Galactosidase Suggest that Both Modes Can Co-exist.

PubMed

Durec, Matúš; Marek, Radek; Kozelka, Jiří

2018-04-17

In proteins, the indole side chain of tryptophan can interact with water molecules either in-plane, forming hydrogen bonds, or out-of-plane, with the water molecule contacting the aromatic π face. The latter interaction can be either of the lone pair⋅⋅⋅π (lp⋅⋅⋅π) type or corresponds to the O-H⋅⋅⋅π binding mode, an ambiguity that X-ray structures usually do not resolve. Here, we report molecular dynamics (MD) simulations of a solvated β-galactosidase monomer, which illustrate how a water molecule located at the π face of an indole side chain of tryptophan can adapt to the position of proximate residues and "select" its binding mode. In one such site, the water molecule is predicted to rapidly oscillate between the O-H⋅⋅⋅π and lp⋅⋅⋅π binding modes, thus gaining entropic advantage. Our MD simulations provide support for the role of lp⋅⋅⋅π interactions in the stabilization of protein structures. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

TDO as a therapeutic target in brain diseases.

PubMed

Yu, Cheng-Peng; Pan, Ze-Zheng; Luo, Da-Ya

2016-08-01

Tryptophan-2, 3-dioxygenase (TDO) is a heme-containing protein catalyzing the first reaction in the kynurenine pathway, which incorporates oxygen into the indole moiety of tryptophan and catalyzes it into kynurenine (KYN). The activation of TDO results in the depletion of tryptophan and the accumulation of kynurenine and its metabolites. These metabolites can affect the function of neurons and inhibit the proliferation of T cells. Increasing evidence demonstrates that TDO is a potential therapeutic target in the treatment of brain diseases as well as in the antitumor and transplant fields. Despite its growing popularity, there are few reviews only focusing on TDO. Hence, we herein review TDO by providing a comprehensive overview of TDO, including its biological functions as well as the evolution, structure and catalytic process of TDO. Additionally, this review will focus on the role of TDO in the pathology of three groups of brain diseases: Schizophrenia, Alzheimer's disease (AD) and Glioma. Finally, we will also provide an opinion regarding the future developmental directions of TDO in brain diseases, especially whether TDO has a potential role in other brain diseases as well as the development and applications of TDO inhibitors as treatments.

Interaction of MreB-derived antimicrobial peptides with membranes.

PubMed

Saikia, Karabi; Chaudhary, Nitin

2018-03-25

Antimicrobial peptides are critical components of defense systems in living forms. The activity is conferred largely by the selective membrane-permeabilizing ability. In our earlier work, we derived potent antimicrobial peptides from the 9-residue long, N-terminal amphipathic helix of E. coli MreB protein. The peptides display broad-spectrum activity, killing not only Gram-positive and Gram-negative bacteria but opportunistic fungus, Candida albicans as well. These results proved that membrane-binding stretches of bacterial proteins could turn out to be self-harming when applied from outside. Here, we studied the membrane-binding and membrane-perturbing potential of these peptides. Steady-state tryptophan fluorescence studies with tryptophan extended peptides, WMreB 1-9 and its N-terminal acetylated analog, Ac-WMreB 1-9 show preferential binding to negatively-charged liposomes. Both the peptides cause permeabilization of E. coli inner and outer-membranes. Tryptophan-lacking peptides, though permeabilize the outer-membrane efficiently, little permeabilization of the inner-membrane is observed. These data attest membrane-destabilization as the mechanism of rapid bacterial killing. This study is expected to motivate the research in identifying microbes' self-sequences to combat them. Copyright © 2018 Elsevier Inc. All rights reserved.

Influence of the feedback loops in the trp operon of B. subtilis on the system dynamic response and noise amplitude.

PubMed

Zamora-Chimal, Criseida; Santillán, Moisés; Rodríguez-González, Jesús

2012-10-07

In this paper we introduce a mathematical model for the tryptophan operon regulatory pathway in Bacillus subtilis. This model considers the transcription-attenuation, and the enzyme-inhibition regulatory mechanisms. Special attention is paid to the estimation of all the model parameters from reported experimental data. With the aid of this model we investigate, from a mathematical-modeling point of view, whether the existing multiplicity of regulatory feedback loops is advantageous in some sense, regarding the dynamic response and the biochemical noise in the system. The tryptophan operon dynamic behavior is studied by means of deterministic numeric simulations, while the biochemical noise is analyzed with the aid of stochastic simulations. The model feasibility is tested comparing its stochastic and deterministic results with experimental reports. Our results for the wildtype and for a couple of mutant bacterial strains suggest that the enzyme-inhibition feedback loop, dynamically accelerates the operon response, and plays a major role in the reduction of biochemical noise. Also, the transcription-attenuation feedback loop makes the trp operon sensitive to changes in the endogenous tryptophan level, and increases the amplitude of the biochemical noise. Copyright © 2012 Elsevier Ltd. All rights reserved.

Serotonin neurotransmission in anorexia nervosa.

PubMed

Haleem, Darakhshan Jabeen

2012-09-01

Patients with anorexia nervosa (AN) show extreme dieting weight loss, hyperactivity, depression/anxiety, self-control, and behavioral impulsivity. 5-Hydroxytryptamine (5-HT; serotonin) is involved in almost all the behavioral changes observed in AN patients. Both genetic and environmental factors contribute toward the pathogenesis of AN. It is a frequent disorder among adolescent girls and young women and starts as an attempt to lose weight to look beautiful and attractive. Failure to see the turning point when fasting becomes unreasonable leads to malnutrition and AN. Tryptophan, the precursor of serotonin and an essential amino acid, is only available in the diet. It is therefore likely that excessive diet restriction and malnutrition decrease brain serotonin stores because the precursor is less available to the rate-limiting enzyme of 5-HT biosynthesis, which normally exists unsaturated with its substrate. Evidence shows that diet restriction-induced exaggerated feedback control over 5-HT synthesis and the smaller availability of tryptophan decreases serotonin neurotransmission at postsynaptic sites, leading to hyperactivity, depression, and behavioral impulsivity. A compensatory upregulation of postsynaptic 5-HT-1A receptors and hypophagic serotonin receptors may be involved in anxiety and suppression of appetite. It is suggested that tryptophan supplementation may improve pharmacotherapy in AN.

Homology modeling, molecular docking and molecular dynamics studies of the catalytic domain of chitin deacetylase from Cryptococcus laurentii strain RY1.

PubMed

Sarkar, Soumyadev; Gupta, Suchetana; Chakraborty, Writachit; Senapati, Sanjib; Gachhui, Ratan

2017-11-01

This study provides structural insights into chitin deacetylase, over-expressing under nitrogen limiting condition in Cryptococcus laurentii strain RY1. The enzyme converts chitin, the second most abundant natural biopolymer, to chitosan, which offers tremendous applications in diverse fields. To elucidate the structure-function relationship of this biologically and industrially important enzyme, a homology model of the catalytic domain was constructed. The stability of the structure was assessed by molecular dynamics simulation studies. Tryptophan 151 of the domain was identified to form hydrogen bond and stacking interaction with chitin upon docking. In Silico substitution of Tryptophan (W) to Alanine (A), Phenylalanine (F) and Aspartate (D) corroborated the importance of the Tryptophan residue in interaction with the substrate. This is the first report of unravelling the structural characteristics of chitin deacetylase from Cryptococcus and understanding the approach of the enzyme towards its substrate. Our results would be helpful to perform experimental validations and apply quantum mechanics/molecular mechanics techniques to determine the detailed catalytic mechanism and enhance the industrial potency of the enzyme. Copyright © 2017 Elsevier B.V. All rights reserved.

Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

NASA Technical Reports Server (NTRS)

Rutherford, R.; Gallois, P.; Masson, P. H.

1998-01-01

Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

Functional gold nanoparticle-based antibacterial agents for nosocomial and antibiotic-resistant bacteria.

PubMed

Kuo, Yen-Ling; Wang, Sin-Ge; Wu, Ching-Yi; Lee, Kai-Chieh; Jao, Chan-Jung; Chou, Shiu-Huey; Chen, Yu-Chie

2016-10-01

Medical treatments for bacterial-infections have become challenging because of the emergence of antibiotic-resistant bacterial strains. Thus, new therapeutics and antibiotics must be developed. Arginine and tryptophan can target negatively-charged bacteria and penetrate bacterial cell membrane, respectively. Synthetic-peptides containing arginine, tryptophan and cysteine termini, in other words, (DVFLG)2REEW4C and (DVFLG)2REEW2C, as starting materials were mixed with aqueous tetrachloroauric acid to generate peptide-immobilized gold nanoparticles (i.e., [DVFLG]2REEW4C-AuNPs and [DVFLG]2REEW2C-AuNPs) through one-pot reactions. The peptide immobilized AuNPs exhibit targeting capacity and antibacterial activity. Furthermore, (DVFLG)2REEW4C-AuNPs immobilized with a higher number of tryptophan molecules possess more effective antibacterial capacity than (DVFLG)2REEW2C-AuNPs. Nevertheless, they are not harmful for animal cells. The feasibility of using the peptide-AuNPs to inhibit the cell growth of bacterium-infected macrophages was demonstrated. These results suggested that the proposed antibacterial AuNPs are effective antibacterial agents for Staphylococci, Enterococci and antibiotic-resistant bacterial strains. [Formula: see text].

Synthesis, characterization and toxicity studies of pyridinecarboxaldehydes and L-tryptophan derived Schiff bases and corresponding copper (II) complexes.

PubMed

Malakyan, Margarita; Babayan, Nelly; Grigoryan, Ruzanna; Sarkisyan, Natalya; Tonoyan, Vahan; Tadevosyan, Davit; Matosyan, Vladimir; Aroutiounian, Rouben; Arakelyan, Arsen

2016-01-01

Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biological activities and thus actively used in the drug development process. The aim of the present study was the synthesis and characterization of new Schiff bases and their copper (II) complexes, derived from L-tryptophan and isomeric (2-; 3-; 4-) pyridinecarboxaldehydes, as well as the assessment of their toxicity in vitro . The optimal conditions of the Schiff base synthesis resulting in up to 75-85% yield of target products were identified. The structure-activity relationship analysis indicated that the location of the carboxaldehyde group at 2-, 3- or 4-position with regard to nitrogen of the pyridine ring in aldehyde component of the L-tryptophan derivative Schiff bases and corresponding copper complexes essentially change the biological activity of the compounds. The carboxaldehyde group at 2- and 4-positions leads to the higher cytotoxic activity, than that of at 3-position, and the presence of the copper in the complexes increases the cytotoxicity. Based on toxicity classification data, the compounds with non-toxic profile were identified, which can be used as new entities in the drug development process using Schiff base scaffold.

Deciphering the fluorescence resonance energy transfer from denatured transport protein to anthracene 1,5 disulphonate in reverse micellar environment

NASA Astrophysics Data System (ADS)

Singharoy, Dipti; Bhattacharya, Subhash Chandra

2017-12-01

Constrained environmental effect inside AOT reverse micellar media has been employed in this work to collect the information about energy transfer efficacy between sodium salt of anthracene 1,5 disulphonate (1,5-AS) with model transport proteins, bovine serum albumin (BSA), and human serum albumin (HSA). Steady state, time-resolved fluorescence and circular dichroism techniques have been used for this purpose and corresponding Fӧrster-type resonance energy transfer (FRET) from tryptophan residues to 1,5-AS indicates that 1,5-AS binds in the vicinity of the tryptophan residue (BSA and HSA) with equal strength. Indication of protein damage from fluorescence data and its confirmation has been measured from CD measurement. Molecular modeling study hereby plays a crucial role to predict the minimum energy docked conformation of the probe inside the protein environment. From the docked conformation the distance between 1,5-AS and tryptophan moiety of BSA/HSA has successfully explained the FRET possibility between them. A comparative modeling study between BSA and HSA with 1,5-AS assigning their binding site within specific amino acids plays a crucial role in support of the FRET study.

Tryptophan Depletion and Emotional Processing in Healthy Volunteers at High Risk for Depression

PubMed Central

Feder, Adriana; Skipper, Jamie; Blair, James R.; Buchholz, Katherine; Mathew, Sanjay J.; Schwarz, Markus; Doucette, John T.; Alonso, Angelique; Collins, Katherine A.; Neumeister, Alexander; Charney, Dennis S.

2014-01-01

Background Studies in depressed patients have demonstrated the presence of emotional bias toward negative stimuli, as well as dysregulated brain serotonin function. The present study compared the effects of acute tryptophan depletion (ATD) on both an emotional processing and a planning task in never-depressed healthy volunteers at high and low familial risk for depression. Methods Young adults with no personal psychiatric history were stratified into two groups based on family history (n = 25). Participants were enrolled in a randomized, double-blind, placebo-controlled crossover ATD study and completed the affective go/no-go and Tower of London tasks once during each condition. Results There was a significant treatment by valence by group interaction on the affective go/no-go, driven primarily by a greater frequency of inappropriate responses to sad than to happy distracters in the high-risk group during ATD. No group differences were observed on the Tower of London. Conclusions Asymptomatic individuals at high familial risk for depression showed abnormalities in emotional processing while undergoing experimentally induced tryptophan depletion. These findings support emotional processing disturbances as potential trait-level abnormalities associated with the risk of mood disorder. PMID:21377656

Activation of Tryptophan and Phenylalanine Catabolism in the Remission Phase of Allergic Contact Dermatitis: A Pilot Study.

PubMed

Zinkevičienė, Auksė; Kainov, Denis; Girkontaitė, Irutė; Lastauskienė, Eglė; Kvedarienė, Violeta; Fu, Yu; Anders, Simon; Velagapudi, Vidya

2016-01-01

Allergic contact dermatitis (ACD) is an inflammatory skin disease caused by repeated skin exposure to contact allergens. The severity and duration of this disease are associated with many different factors. Some of these factors may represent markers for monitoring disease activity and the individual response to an intervention. We used a targeted metabolomics approach to find such factors in the serum of individuals with ACD. Metabolomics profiles were examined and compared in the acute phase of the disease and also in the absence of disease activity. Our study identified a significant remission phase of ACD-associated systemic biochemical shifts in 2 metabolic pathways: tryptophan-kynurenine and phenylalanine-tyrosine. Although the responsible mechanisms are unclear, these results suggest that the remission phase of ACD is linked to tryptophan metabolism via kynurenine and phenylalanine-tyrosine pathways. However, further replication studies with a larger number of subjects and their subgroups are necessary to validate our results. These studies may provide a new perspective with which to understand the mechanism of and find potential biomarkers of ACD, as well as a new reference for personalized treatment. © 2016 S. Karger AG, Basel.

Structure of the cyclic peptide [W8S]contryphan Vn: effect of the tryptophan/serine substitution on trans-cis proline isomerization.

PubMed

Nepravishta, Ridvan; Mandaliti, Walter; Melino, Sonia; Eliseo, Tommaso; Paci, Maurizio

2014-12-01

The structural characterization of [W8S]contryphan Vn, an analogue of Contryphan Vn with tryptophan 8 substituted with a serine residue (W8S), was performed by NMR spectroscopy, molecular dynamics simulations and fluorescence spectroscopy. Contryphan Vn, a bioactive cyclic peptide from the venom of the cone snail Conus ventricosus, contains an S-S bridge between two cysteines and a D-tryptophan. Like other Contryphans, [W8S]contryphan Vn has proline 7 isomerized trans, while the proline 4 has nearly equivalent populations of cis and trans configurations. The thermodynamic and kinetic parameters of the trans-cis isomerization of proline 4 were measured. The isomers of [W8S]contryphan Vn with proline 4 in cis and trans show structural differences. The absence of the salt bridge between the same Asp2 and Lys6, present in Contryphan Vn, may be attributed to the lack of the hydrophobic side chain of Trp8 where it likely protects the electrostatic interactions. These results may contribute to identifying, in these cyclic peptides, the structural determinants of the mechanism of proline trans-cis isomerization, this being also an important step in protein folding.

Synthesis, characterization and toxicity studies of pyridinecarboxaldehydes and L-tryptophan derived Schiff bases and corresponding copper (II) complexes

PubMed Central

Malakyan, Margarita; Babayan, Nelly; Grigoryan, Ruzanna; Sarkisyan, Natalya; Tonoyan, Vahan; Tadevosyan, Davit; Matosyan, Vladimir; Aroutiounian, Rouben; Arakelyan, Arsen

2016-01-01

Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biological activities and thus actively used in the drug development process. The aim of the present study was the synthesis and characterization of new Schiff bases and their copper (II) complexes, derived from L-tryptophan and isomeric (2-; 3-; 4-) pyridinecarboxaldehydes, as well as the assessment of their toxicity in vitro. The optimal conditions of the Schiff base synthesis resulting in up to 75-85% yield of target products were identified. The structure-activity relationship analysis indicated that the location of the carboxaldehyde group at 2-, 3- or 4-position with regard to nitrogen of the pyridine ring in aldehyde component of the L-tryptophan derivative Schiff bases and corresponding copper complexes essentially change the biological activity of the compounds. The carboxaldehyde group at 2- and 4-positions leads to the higher cytotoxic activity, than that of at 3-position, and the presence of the copper in the complexes increases the cytotoxicity. Based on toxicity classification data, the compounds with non-toxic profile were identified, which can be used as new entities in the drug development process using Schiff base scaffold. PMID:28344771

CARD9 impacts colitis by altering gut microbiota metabolism of tryptophan into aryl hydrocarbon receptor ligands.

PubMed

Lamas, Bruno; Richard, Mathias L; Leducq, Valentin; Pham, Hang-Phuong; Michel, Marie-Laure; Da Costa, Gregory; Bridonneau, Chantal; Jegou, Sarah; Hoffmann, Thomas W; Natividad, Jane M; Brot, Loic; Taleb, Soraya; Couturier-Maillard, Aurélie; Nion-Larmurier, Isabelle; Merabtene, Fatiha; Seksik, Philippe; Bourrier, Anne; Cosnes, Jacques; Ryffel, Bernhard; Beaugerie, Laurent; Launay, Jean-Marie; Langella, Philippe; Xavier, Ramnik J; Sokol, Harry

2016-06-01

Complex interactions between the host and the gut microbiota govern intestinal homeostasis but remain poorly understood. Here we reveal a relationship between gut microbiota and caspase recruitment domain family member 9 (CARD9), a susceptibility gene for inflammatory bowel disease (IBD) that functions in the immune response against microorganisms. CARD9 promotes recovery from colitis by promoting interleukin (IL)-22 production, and Card9(-/-) mice are more susceptible to colitis. The microbiota is altered in Card9(-/-) mice, and transfer of the microbiota from Card9(-/-) to wild-type, germ-free recipients increases their susceptibility to colitis. The microbiota from Card9(-/-) mice fails to metabolize tryptophan into metabolites that act as aryl hydrocarbon receptor (AHR) ligands. Intestinal inflammation is attenuated after inoculation of mice with three Lactobacillus strains capable of metabolizing tryptophan or by treatment with an AHR agonist. Reduced production of AHR ligands is also observed in the microbiota from individuals with IBD, particularly in those with CARD9 risk alleles associated with IBD. Our findings reveal that host genes affect the composition and function of the gut microbiota, altering the production of microbial metabolites and intestinal inflammation.

Interaction of Tryptophane and Phenylalanine with Cadmium and Molybdenum Ferrocyanides and Its Implications in Chemical Evolution and Origins of Life.

NASA Astrophysics Data System (ADS)

Tewari, Brij

2016-07-01

Insoluble metal hexacyanoferrate(II) complexes could have concentrated biomonomers from dilute prebiotic soup during course of chemical evolution and origin of life or primitive earth. In the light of above hypothesis, adsorption of tryptophane and phenylalanine was studied on cadmium and molybdenum ferrocyanides at neutral pH (7.0 ± 0.01) and at a temperature of 30 ± 1º C. Interaction of amino acids with metal ferrocyanides are found to be maximum at neutral pH. Neutral pH is chosen for the adsorption studies because most of the reactions in biological systems taken place at neutral pH range. Adsorption trend follow Langmuir isotherm model. The Langmuir constants b and Qo were calculated at neutral pH, tryptophane was found to more adsorbed than phenylalanine on both metal ferrocyanides studied. Molybdenum ferrocyanides studied. Molybdenum ferrocyanides was found to have more uptake capacity for both adsorbates than cadmium ferrocyanides. The present study suggests that metal ferrocyanides might have played a role in the stabilization of biomolecules through their surface activity during course of chemical solution and origins of life on primitive earth.

Enantioselective Metabolism and Interference on Tryptophan Metabolism of Myclobutanil in Rat Hepatocytes.

PubMed

Wang, Yao; Qiu, Jing; Zhu, Wentao; Wang, Xinru; Zhang, Ping; Wang, Dezhen; Zhou, Zhiqiang

2015-09-01

Myclobutanil, (RS)-2-(4-chlorophenyl)-2-(1H-1, 2, 4-triazol-1-ylmethyl) hexanenitrile is a widely used triazole fungicide. In this study, enantioselective metabolism and cytotoxicity were investigated in rat hepatocytes by chiral HPLC-MS/MS and the methyl tetrazolium (MTT) assay, respectively. Furthermore, tryptophan metabolism disturbance in rat hepatocytes after myclobutanil exposure was also evaluated by target metabolomics method. The half-life (t1/2) of (+)-myclobutanil was 10.66 h, whereas that for (-)-myclobutanil was 15.07 h. Such results indicated that the metabolic process of myclobutanil in rat hepatocytes was enantioselective with an enrichment of (-)-myclobutanil. For the cytotoxicity research, the calculated EC50 (12 h) values for rac-myclobutanil, (+)- and (-)-myclobutanil were 123.65, 150.65 and 152.60 µM, respectively. The results of tryptophan metabolites profiling showed that the levels of kynurenine (KYN) and XA were both up-regulated compared to the control, suggesting the activation effect of the KYN pathway by myclobutanil and its enantiomers which may provide an important insight into its toxicity mechanism. The data presented here could be useful for the environmental hazard assessment of myclobutanil. © 2015 Wiley Periodicals, Inc.

Functional changes in cerebral 5-hydroxytryptamine metabolism in the mouse induced by anticonvulsant drugs.

PubMed Central

Chadwick, D; Gorrod, J W; Jenner, P; Marsden, C D; Reynolds, E H

1978-01-01

1 Acute administration of clonazepam, diazepam, and diphenylhydantoin to mice elevated cerebral 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA); chronic administration had less effect. 2 Acute administration of clonazepam and diazepam but not diphenylhydantoin raised cerebral trytophan levels; chronic administration of clonazepam caused a smaller elevation of cerebral tryptophan but chronic administration of diazepam still caused a large rise in cerebral tryptophan. 3 Neither clonazepam nor diazepam caused induction of drug metabolizing enzymes on chronic administration but diphenylhydantoin had a marked effect. 4 These data suggest that the altered 5-HT metabolism caused by these compounds is unrelated to a common action on tryptophan levels, and that the reduced effect of clonazepam and diazepam on chronic administration cannot be attributed to increased metabolism of these compounds. 5 Clonazepam induced abnormal head movements in mice in a dose-dependent manner. Pretreatment of animals with tranylcypromine increased the intensity of movement, although pargyline was without effect. Similar effects were observed with diazepam and diphenylhydantoin, suggesting that the increase in cerebral 5-HT caused by these compounds is of functional significance in stimulating 5-HT receptors. PMID:620092

Redox Properties of Tryptophan Metabolism and the Concept of Tryptophan Use in Pregnancy

PubMed Central

Xu, Kang; Liu, Hongnan; Bai, Miaomiao; Gao, Jing; Wu, Xin; Yin, Yulong

2017-01-01

During pregnancy, tryptophan (Trp) is required for several purposes, and Trp metabolism varies over time in the mother and fetus. Increased oxidative stress (OS) with high metabolic, energy and oxygen demands during normal pregnancy or in pregnancy-associated disorders has been reported. Taking the antioxidant properties of Trp and its metabolites into consideration, we made four hypotheses. First, the use of Trp and its metabolites is optional based on their antioxidant properties during pregnancy. Second, dynamic Trp metabolism is an accommodation mechanism in response to OS. Third, regulation of Trp metabolism could be used to control/attenuate OS according to variations in Trp metabolism during pregnancy. Fourth, OS-mediated injury could be alleviated by regulation of Trp metabolism in pregnancy-associated disorders. Future studies in normal/abnormal pregnancies and in associated disorders should include measurements of free Trp, total Trp, Trp metabolites, and activities of Trp-degrading enzymes in plasma. Abnormal pregnancies and some associated disorders may be associated with disordered Trp metabolism related to OS. Mounting evidence suggests that the investigation of the use of Trp and its metabolites in pregnancy will be meanful. PMID:28737706

Quantitative determination of conformational, dynamic, and kinetic parameters of a ligand-protein/DNA complex from a complete relaxation and conformational exchange matrix analysis of intermolecular transferred NOESY.

PubMed

Moseley, H N; Lee, W; Arrowsmith, C H; Krishna, N R

1997-05-06

We report a quantitative analysis of the 13C-edited intermolecular transferred NOESY (inter-TrNOESY) spectrum of the trp-repressor/operator complex (trp-rep/op) with [ul-13C/15N]-L-tryptophan corepressor using a computer program implementing complete relaxation and conformational exchange matrix (CORCEMA) methodology [Moseley et al. (1995) J. Magn. Reson. 108B, 243-261]. Using complete mixing time curves of three inter-TrNOESY peaks between the tryptophan and the Trp-rep/op, this self-consistent analysis determined the correlation time of the bound species (tauB = 13.5 ns) and the exchange off-rate (k(off) = 3.6 s(-1)) of the corepressor. In addition, the analysis estimated the correlation time of the free species (tauF approximately 0.15 ns). Also, we demonstrate the sensitivity of these inter-TrNOESY peaks to several factors including the k(off) and orientation of the tryptophan corepressor within the binding site. The analysis indicates that the crystal structure orientation for the corepressor is compatible with the solution NMR data.

Assorted interactions of amino acids prevailing in aqueous vitamin C solutions probed by physicochemical and ab-initio contrivances

NASA Astrophysics Data System (ADS)

Das, Koyeli; Roy, Milan Chandra; Rajbanshi, Biplab; Roy, Mahendra Nath

2017-11-01

Qualitative and quantitative analysis of molecular interaction prevailing in tyrosine and tryptophan in aqueous solution of vitamin C have been probed by thermophysical properties. The apparent molar volume (ϕV), viscosity B-coefficient, molal refraction (RM) of tyrosine and tryptophan have been studied in aqueous vitamin C solutions at diverse temperatures via Masson equation which deduced solute-solvent and solute-solute interactions, respectively. Spectroscopic study along with physicochemical and computational techniques provides lots of interesting and highly significant insights of the model biological systems. The overall results established strong solute-solvent interactions between studied amino acids and vitamin C mixture in the ternary solutions.

Study on the interaction mechanism between aromatic amino acids and quercetin

NASA Astrophysics Data System (ADS)

Gou, Xingxing; Pu, Xiaohua; Li, Zongxiao

2017-11-01

In this paper, we selected quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) as the research objects to investigate the change rules in the reaction process. The thermodynamic functions (Ka, Δ G, and Δ S) of the interactions between quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) were measured by isothermal titration calorimetry. The values of binding constant (Ka) reached maximum at 25°C; the entropies and Gibbs free energies were both negative at different temperatures. The kinetic parameters of quercetin and amino acids in the interaction process was determined by microcalorimetry. The results inferred that the driving force of the reaction was hydrogen bond or van der Waals force.

Tryptophan promotes charitable donating

PubMed Central

Steenbergen, Laura; Sellaro, Roberta; Colzato, Lorenza S.

2014-01-01

The link between serotonin (5-HT) and one of the most important elements of prosocial behavior, charity, has remained largely uninvestigated. In the present study, we tested whether charitable donating can be promoted by administering the food supplement L-Tryptophan (TRP), the biochemical precursor of 5-HT. Participants were compared with respect to the amount of money they donated when given the opportunity to make a charitable donation. As expected, compared to a neutral placebo, TRP appears to increase the participants’ willingness to donate money to a charity. This result supports the idea that the food we eat may act as a cognitive enhancer modulating the way we think and perceive the world and others. PMID:25566132

Estradiol or fluoxetine alters depressive behavior and tryptophan hydroxylase in rat raphe.

PubMed

Yang, Fu-Zhong; Wu, Yan; Zhang, Wei-Guo; Cai, Yi-Yun; Shi, Shen-Xun

2010-03-10

The effects of 17beta-estradiol and fluoxetine on behavior of ovariectomized rats subjected to the forced swimming test and the expression of tryptophan hydroxylase (TPH) in dorsal and median raphe were investigated, respectively through time sampling technique of behavior scoring and immunohistochemistry. Both estradiol and fluoxetine increased swimming and decreased immobility in the forced swimming test. The forced swimming stress decreased integrated optical density of TPH-positive regions in dorsal and median raphe. Both estradiol and fluoxetine administration prevented integrated optical density of TPH-positive regions from being decreased by forced swimming stress. These observations suggest that both estradiol and fluoxetine have protective bearing on ovariectomized rats enduring forced swimming stress.

High histologic grade and increased relative content of tryptophan in breast cancer using ratios from fingerprint fluorescence spectral peaks

NASA Astrophysics Data System (ADS)

Sordillo, Laura A.; Sordillo, Peter P.; Budansky, Yury; Pu, Yang; Alfano, R. R.

2015-03-01

Histologic grade is a very important, but underappreciated, parameter of breast cancer aggressiveness. Despite its importance, it has historically not been included as one of the criteria for staging of this cancer. In this study, spectral fluorescence profiles from patients with breast carcinoma were acquired. Ratios of emission peaks at 340 over 440,460 nm from biomolecules in malignant and normal samples were calculated. Cancerous over normal ratios (double ratio (DR) method) were evaluated with respect to tumor characteristics. Increased tryptophan content in breast cancer tissues correlates strongly with high grade, but not with lymph node metastases, estrogen receptor, progesterone receptor or Her-2-Neu receptor status.

Threshold ionization spectroscopic investigation of supersonic jet-cooled, laser-desorbed Tryptophan

NASA Astrophysics Data System (ADS)

Taherkhani, Mehran; Armentano, Antonio; Černý, Jiří; Müller-Dethlefs, Klaus

2016-07-01

Tryptophan (Trp) was studied by two-colour Photoionization Efficiency (PIE) and Mass Analysed Threshold Ionization (MATI) spectroscopy using a laser desorption apparatus. Conformer A of Trp was excited into the S1 state (34,878 cm-1) and the second laser was scanned around the D0 cation ground and the D1 excited state. No ionization signal into the D0 state could be found, but a clear threshold was observed for the D1 state with an ionization energy of 66,704 ± 3 cm-1 (8.27 eV). This observation is explained in terms of the electronic configurations of the S1 and cationic states.

Oxidation in the complementarity-determining regions differentially influences the properties of therapeutic antibodies

PubMed Central

Dashivets, Tetyana; Stracke, Jan; Dengl, Stefan; Knaupp, Alexander; Pollmann, Jan; Buchner, Johannes; Schlothauer, Tilman

2016-01-01

ABSTRACT Therapeutic antibodies can undergo a variety of chemical modification reactions in vitro. Depending on the site of modification, either antigen binding or Fc-mediated functions can be affected. Oxidation of tryptophan residues is one of the post-translational modifications leading to altered antibody functionality. In this study, we examined the structural and functional properties of a therapeutic antibody construct and 2 affinity matured variants thereof. Two of the 3 antibodies carry an oxidation-prone tryptophan residue in the complementarity-determining region of the VL domain. We demonstrate the differences in the stability and bioactivity of the 3 antibodies, and reveal differential degradation pathways for the antibodies susceptible to oxidation. PMID:27612038

The study of esophageal cancer in an early stage by using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Ishigaki, Mika; Taketani, Akinori; Maeda, Yasuhiro; Andriana, Bibin B.; Ishihara, Ryu; Sato, Hidetoshi

2013-02-01

The esophageal cancer is a disease with a high mortality. In order to lead a higher survival rate five years after the cancer's treatment, we inevitably need a method to diagnose the cancer in an early stage and support the therapy. Raman spectroscopy is one of the most powerful techniques for the purpose. In the present study, we apply Raman spectroscopy to obtain ex vivo spectra of normal and early tumor human esophageal sample. The result of principal component analysis indicates that the tumor tissue is associated with a decrease in tryptophan concentration. Furthermore, we can predict the tissue type with 80% accuracy by linear discriminant analysis which model is made by tryptophan bands.

Isotopic exchange of hydrogen in aromatic amino acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pshenichnikova, A.B.; Karnaukhova, E.N.; Mitsner, B.I.

The kinetics of the isotopic replacement of hydrogen in the aromatic amino acids L-tryptophan, L-tyrosine, and L-phenylalanine in solutions of deuterochloric and deuterosulfuric acids in deuterium oxide were investigated by PMR spectroscopy. The reactions were shown to be of first orders with respect both to the concentration of the substrate and to the activity of the deuterium ion. The isotopic effects of hydrogen and the values of the activation energy of H-D exchange in different positions of the aromatic ring in tryptophan and tyrosine were determined. The effect of properties of the medium on the rate of the isotopic exchangemore » of hydrogen is discussed. 17 refs., 2 figs., 2 tabs.« less

Oxidative tryptophan modification by terpene- and squalene-hydroperoxides and a possible link to cross-reactions in diagnostic tests.

PubMed

Natsch, Andreas; Emter, Roger; Badertscher, Remo P; Brunner, Gerhard; Granier, Thierry; Kern, Susanne; Ellis, Graham

2015-06-15

Hydroperoxides can act as specific haptens and oxidatively modify proteins. Terpene hydroperoxides trigger unusually high frequencies of positive skin reactions in human patients if tested at high concentrations. It is unknown whether this is due to specific hapten formation. Here, we show that both terpene hydroperoxides and the endogenous hydroperoxide formed from squalene can oxidatively modify tryptophan. Oxidative modifications of Trp were recently postulated to explain cross-sensitization between unrelated photosensitizers. Current observations may extend this hypothesis: Oxidative events triggered by endogenous hydroperoxides and hydroperoxides/oxidants derived from xenobiotics might lead to a sensitized state detected by patch tests with high concentrations of hydroperoxides.

No evidence for interstellar proteins

NASA Astrophysics Data System (ADS)

Koch, R. H.; Davies, R. E.

1984-03-01

The claim by Karim et al. (1983) that the broad interstellar feature near 280 nm suggests the existence of proteinaceous matter in the interstellar medium is addressed. From astronomical and biochemical arguments it is shown that no quantitative measures of optical depth can be derived from the published data and that there is a great wealth of organic molecules which have absorptions at or near this wavelength interval. The amino acid tryptophan is one such molecule but the deduced spectrum does not satisfy two other properties of its spectrum. In particular, the 280 nm absorption for tryptophan refers to an aqueous solution of the molecule, and no liquid water is expected to exist in the ISM.

Short communication: Suitability of fluorescence spectroscopy for characterization of commercial milk of different composition and origin.

PubMed

Ntakatsane, M P; Yang, X Q; Lin, M; Liu, X M; Zhou, P

2011-11-01

Thirteen milk brands comprising 76 pasteurized and UHT milk samples of various compositions (whole, reduced fat, skimmed, low lactose, and high protein) were obtained from local supermarkets, and milk samples manufactured in various countries were discriminated using front-face fluorescence spectroscopy (FFFS) coupled with chemometric tools. The emission spectra of Maillard reaction products and riboflavin (MRP/RF; 400 to 600 nm) and tryptophan (300 to 400 nm) were recorded using FFFS, and the excitation wavelengths were set at 360 nm for MRP/RF and 290 nm for tryptophan. Principal component analysis (PCA) was applied to analyze the normalized spectra. The PCA of spectral information from MRP/RF discriminated the milk samples originating in different countries, and PCA of spectral information from tryptophan discriminated the samples according to composition. The fluorescence spectral data were compared with liquid chromatography-mass spectrometry results for the glycation extent of the milk samples, and a positive association (R(2)=0.84) was found between the degree of glycation of α-lactalbumin and the MRP/RF spectral data. This study demonstrates the ability and sensitivity of FFFS to rapidly discriminate and classify commercial milk with various compositions and processing conditions. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Optical properties and antimicrobial effects of silver nanoparticles synthesized by femtosecond laser photoreduction

NASA Astrophysics Data System (ADS)

dos Santos Courrol, Daniella; Regina Borges Lopes, Carla; da Silva Cordeiro, Thiago; Regina Franzolin, Marcia; Dias Vieira Junior, Nilson; Elgul Samad, Ricardo; Coronato Courrol, Lilia

2018-07-01

Silver nanoparticles exhibit a powerful antimicrobial action showing a pronounced potential to be widely used against drug resistance bacteria. The present work describes the optical properties and antimicrobial effect of silver nanoparticles produced by femtosecond laser photoreduction of AgNO3 in the presence of tryptophan water solution. The advantages of this method are the absence of hazardous chemical reducing agents in the solution, and the versatile dimensional control achieved. The synthesized silver nanoparticles were characterized by absorption and fluorescence spectroscopy and their antibacterial activity were determined by monitoring the cell viability of Escherichia coli. The effects of the silver nanoparticles concentration and laser parameters (exposure time and pulse energy), on the formation of the nanoparticles, and its influence on the bacteria growth inhibition were studied. The prepared silver nanoparticles exhibited suitable antimicrobial properties. The results demonstrated that the nanoparticles concentration plays an important role in their bactericidal efficacy. The increase in the laser energy caused an increase in E. coli growth inhibition. Irradiations with energies around 300 μJ for 60 min presented high antimicrobial activity due to the presence of kynurenine, sub product of tryptophan photolysis. The first-time formation mechanism of tryptophan silver nanoparticles in high optical intensities was also discussed.

Enhanced serotonergic neurotransmission in the hippocampus following tryptophan administration improves learning acquisition and memory consolidation in rats.

PubMed

Haider, Saida; Khaliq, Saima; Haleem, Darakhshan J

2007-01-01

Increasing evidence shows that serotonin (5-hydroxytryptamine - 5-HT) plays a modulatory role in memory functions. 5-HT transmission has been implicated in learning and memory. Both 5-HT depletion and specific 5-HT agonists lower memory performance. Hippocampus is thought to be the key region involved in long-term memory. It is the major limbic target of the brainstem serotonergic neurons that modulate learning. In the present study, we examined the effects of increased hippocampal 5-HT metabolism following tryptophan (TRP) administration on short-term memory (STM) and long-term memory (LTM) in rats. Learning acquisition (LA) and memory consolidation (MC) in rats was also evaluated. TRP at 50 mg/kg and 100 mg/kg body weight was used. Assessment of memory in rats was done using the water maze test (WM) after 6 weeks of daily administration of TRP. The results showed that administration of TRP enhanced both STM and LTM. However, the effect on STM was significant only at the higher dose. Rats administered the higher dose of TRP also exhibited a significant enhancement in LA. A significant effect on MC was also observed in tryptophan-treated rats. The results suggest that serotonergic system in the hippocampus is important in LA and MC in rats.

Diminished central nervous 5-HT neurotransmission and mood self-ratings in children and adolescents with ADHD: no clear effect of rapid tryptophan depletion.

PubMed

Zepf, Florian Daniel; Holtmann, Martin; Stadler, Christina; Magnus, Sophie; Wöckel, Lars; Poustka, Fritz

2009-03-01

Research on 5-HT-functioning in adult patients and healthy subjects using rapid tryptophan depletion (RTD) has indicated weak but stable effects on mood ratings. Altered mood in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) can confound the differential diagnosis between severe ADHD and mood disorders such as pediatric bipolar disorder. The present study investigated the effects of RTD induced lowered central nervous 5-HT-levels on mood self-ratings in children with ADHD. Seventeen boys with ADHD participated in the study in a double-blind within-subject crossover-design. They were administered RTD within an amino acid drink lacking tryptophan, thus lowering central nervous 5-HT-synthesis. On another day they received a placebo. Self-rated mood was assessed on both days at baseline conditions and at three different post-drink time-points. RTD had no clear effect on mood within the whole sample. Low scorers on venturesomeness were more strongly affected by RTD in terms of feelings of inactivity and negative feelings compared to high venture patients. Our data did not show a significant effect of RTD on mood self-ratings. However, the findings must be considered as preliminary and require further replication, in particular as they could be due to sampling bias.

Mechanistic Insights into Radical-Mediated Oxidation of Tryptophan from ab Initio Quantum Chemistry Calculations and QM/MM Molecular Dynamics Simulations.

PubMed

Wood, Geoffrey P F; Sreedhara, Alavattam; Moore, Jamie M; Wang, John; Trout, Bernhardt L

2016-05-12

An assessment of the mechanisms of (•)OH and (•)OOH radical-mediated oxidation of tryptophan was performed using density functional theory calculations and ab initio plane-wave Quantum Mechanics/Molecular Mechanics (QM/MM) molecular dynamics simulations. For the (•)OH reactions, addition to the pyrrole ring at position 2 is the most favored site with a barrierless reaction in the gas phase. The subsequent degradation of this adduct through a H atom transfer to water was intermittently observed in aqueous-phase molecular dynamics simulations. For the (•)OOH reactions, addition to the pyrrole ring at position 2 is the most favored pathway, in contrast to the situation in the model system ethylene, where concerted addition to the double bond is preferred. From the (•)OOH position 2 adduct QM/MM simulations show that formation of oxy-3-indolanaline occurs readily in an aqueous environment. The observed transformation starts from an initial rupture of the O-O bond followed by a H atom transfer with the accompanying loss of an (•)OH radical to solution. Finally, classical molecular dynamics simulations were performed to equate observed differential oxidation rates of various tryptophan residues in monoclonal antibody fragments. It was found that simple parameters derived from simulation correlate well with the experimental data.

Biophysical studies suggest a new structural arrangement of crotoxin and provide insights into its toxic mechanism

PubMed Central

Fernandes, Carlos A. H.; Pazin, Wallance M.; Dreyer, Thiago R.; Bicev, Renata N.; Cavalcante, Walter L. G.; Fortes-Dias, Consuelo L.; Ito, Amando S.; Oliveira, Cristiano L. P.; Fernandez, Roberto Morato; Fontes, Marcos R. M.

2017-01-01

Crotoxin (CTX) is the main neurotoxin found in Crotalus durissus rattlesnake venoms being composed by a nontoxic and non-enzymatic component (CA) and a toxic phospholipase A2 (CB). Previous crystallographic structures of CTX and CB provided relevant insights: (i) CTX structure showed a 1:1 molecular ratio between CA and CB, presenting three tryptophan residues in the CA/CB interface and one exposed to solvent; (ii) CB structure displayed a tetrameric conformation. This study aims to provide further information on the CTX mechanism of action by several biophysical methods. Our data show that isolated CB can in fact form tetramers in solution; however, these tetramers can be dissociated by CA titration. Furthermore, CTX exhibits a strong reduction in fluorescence intensity and lifetime compared with isolated CA and CB, suggesting that all tryptophan residues in CTX may be hidden by the CA/CB interface. By companying spectroscopy fluorescence and SAXS data, we obtained a new structural model for the CTX heterodimer in which all tryptophans are located in the interface, and the N-terminal region of CB is largely exposed to the solvent. Based on this model, we propose a toxic mechanism of action for CTX, involving the interaction of N-terminal region of CB with the target before CA dissociation. PMID:28256632

Biophysical studies suggest a new structural arrangement of crotoxin and provide insights into its toxic mechanism.

PubMed

Fernandes, Carlos A H; Pazin, Wallance M; Dreyer, Thiago R; Bicev, Renata N; Cavalcante, Walter L G; Fortes-Dias, Consuelo L; Ito, Amando S; Oliveira, Cristiano L P; Fernandez, Roberto Morato; Fontes, Marcos R M

2017-03-03

Crotoxin (CTX) is the main neurotoxin found in Crotalus durissus rattlesnake venoms being composed by a nontoxic and non-enzymatic component (CA) and a toxic phospholipase A 2 (CB). Previous crystallographic structures of CTX and CB provided relevant insights: (i) CTX structure showed a 1:1 molecular ratio between CA and CB, presenting three tryptophan residues in the CA/CB interface and one exposed to solvent; (ii) CB structure displayed a tetrameric conformation. This study aims to provide further information on the CTX mechanism of action by several biophysical methods. Our data show that isolated CB can in fact form tetramers in solution; however, these tetramers can be dissociated by CA titration. Furthermore, CTX exhibits a strong reduction in fluorescence intensity and lifetime compared with isolated CA and CB, suggesting that all tryptophan residues in CTX may be hidden by the CA/CB interface. By companying spectroscopy fluorescence and SAXS data, we obtained a new structural model for the CTX heterodimer in which all tryptophans are located in the interface, and the N-terminal region of CB is largely exposed to the solvent. Based on this model, we propose a toxic mechanism of action for CTX, involving the interaction of N-terminal region of CB with the target before CA dissociation.

Tryptophan Biochemistry: Structural, Nutritional, Metabolic, and Medical Aspects in Humans.

PubMed

Palego, Lionella; Betti, Laura; Rossi, Alessandra; Giannaccini, Gino

2016-01-01

L-Tryptophan is the unique protein amino acid (AA) bearing an indole ring: its biotransformation in living organisms contributes either to keeping this chemical group in cells and tissues or to breaking it, by generating in both cases a variety of bioactive molecules. Investigations on the biology of Trp highlight the pleiotropic effects of its small derivatives on homeostasis processes. In addition to protein turn-over, in humans the pathways of Trp indole derivatives cover the synthesis of the neurotransmitter/hormone serotonin (5-HT), the pineal gland melatonin (MLT), and the trace amine tryptamine. The breakdown of the Trp indole ring defines instead the "kynurenine shunt" which produces cell-response adapters as L-kynurenine, kynurenic and quinolinic acids, or the coenzyme nicotinamide adenine dinucleotide (NAD(+)). This review aims therefore at tracing a "map" of the main molecular effectors in human tryptophan (Trp) research, starting from the chemistry of this AA, dealing then with its biosphere distribution and nutritional value for humans, also focusing on some proteins responsible for its tissue-dependent uptake and biotransformation. We will thus underscore the role of Trp biochemistry in the pathogenesis of human complex diseases/syndromes primarily involving the gut, neuroimmunoendocrine/stress responses, and the CNS, supporting the use of -Omics approaches in this field.

Tryptophan 2,3-Dioxygenfase and Indoleamine 2,3-Dioxygenase 1 Make Separate, Tissue-Specific Contributions to Basal and Inflammation-Induced Kynurenine Pathway Metabolism in Mice

PubMed Central

Larkin, Paul B.; Sathyasaikumar, Korrapati V.; Notarangelo, Francesca M.; Funakoshi, Hiroshi; Nakamura, Toshikazu; Schwarcz, Robert; Muchowski, Paul J.

2018-01-01

In mammals, the majority of the essential amino acid tryptophan is degraded via the kynurenine pathway (KP). Several KP metabolites play distinct physiological roles, often linked to immune system functions, and may also be causally involved in human diseases including neurodegenerative disorders, schizophrenia and cancer. Pharmacological manipulation of the KP has therefore become an active area of drug development. To target the pathway effectively, it is important to understand how specific KP enzymes control levels of the bioactive metabolites in vivo. Here, we conducted a comprehensive biochemical characterization of mice with a targeted deletion of either tryptophan 2,3-dioxygenase (TDO) or indoleamine 2,3-dioxygenase (IDO), the two initial rate-limiting enzymes of the KP. These enzymes catalyze the same reaction, but differ in biochemical characteristics and expression patterns. We measured KP metabolite levels and enzyme activities and expression in several tissues in basal and immune-stimulated conditions. Although our study revealed several unexpected downstream effects on KP metabolism in both knockout mice, the results were essentially consistent with TDO-mediated control of basal KP metabolism and a role of IDO in phenomena involving stimulation of the immune system. PMID:27392942

MiniFluo fluorescence sensor, advances in FDOM Ocean Measurements

NASA Astrophysics Data System (ADS)

Cyr, Frédéric; Tedetti, Marc; Goutx, Madeleine

2017-04-01

As part of the European project "Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management (NeXOS)", we developed the MiniFluo, a glider-compatible optical sensor for measurements of fluorescent dissolved organic matter (FDOM). In situ applications of the MiniFluo are presented here. The configuration used targets both natural (Tryptophan) and an anthropogenic (Phenanthrene) DOM fluorophores. Observations from three glider campaigns in the NW Mediterranean (Fall 2015 and Spring and Summer 2016) are presented. It is shown that the use of the Minifluo highlights new features of DOM dynamics in the region. For example, the Tryptophan (an amino-acid traditionally used as a tracer for waste waters) is found here closely related to open sea Chl-a fluorescence. Differences between Chl-a and Tryptophan fluorescence also give subtle information on seasonal changes in ecosystem structure and DOM release that could not be observed with traditional glider measurements. The study also highlights the presence of phenanthrene (an anthropogenic polycyclic aromatic hydrocarbon (PAH) in the surface and sub-surface waters of the Mediterranean. Implications of these finding will be put in the context of both the Mediterranean Sea DOM dynamics and also the ocean carbon cycle, from which the Dissolved Organic Carbon pool remains qualitatively unknown.

The contribution of component variation and phytoplankton growth to the distribution variation of chromophoric dissolved organic matter content in a mid-latitude subtropical drinking water source reservoir for two different seasons.

PubMed

Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

2017-07-01

The distribution variation in chromophoric dissolved organic matter (CDOM) content in mid-latitude subtropical drinking water source reservoirs (MDWSRs) has great significance in the security of aquatic environments and human health. CDOM distribution is heavily influenced by biogeochemical processes and anthropogenic activity. However, little is known regarding the impact of component variation and phytoplankton growth on CDOM distribution variation in MDWSR. Therefore, samples were collected from a representative MDWSR (the Shanzai Reservoir) for analysis. CDOM absorption and fluorescence coupling with parallel factor analysis were measured and calculated. The results indicated that only two CDOM components were found in the surface water of Shanzai Reservoir, fulvic acid, and high-excitation tryptophan, originating from terrestrial and autochthonous sources, respectively. The types of components did not change with the season. The average molecular weight of CDOM increased in proportion to its fulvic acid content. The distribution variation in CDOM content mainly resulted from the variation in two CDOM components in summer and from high-excitation tryptophan in winter. Phytoplankton growth strongly influenced the distribution variation of CDOM content in summer; the metabolic processes of Cyanobacteria and Bacillariophyta consumed fulvic acid, while that of Cryptophyta produced high-excitation tryptophan.

Interaction of Plasmodium vivax Tryptophan-rich Antigen PvTRAg38 with Band 3 on Human Erythrocyte Surface Facilitates Parasite Growth*

PubMed Central

Alam, Mohd. Shoeb; Choudhary, Vandana; Zeeshan, Mohammad; Tyagi, Rupesh K.; Rathore, Sumit; Sharma, Yagya D.

2015-01-01

Plasmodium tryptophan-rich proteins are involved in host-parasite interaction and thus potential drug/vaccine targets. Recently, we have described several P. vivax tryptophan-rich antigens (PvTRAgs), including merozoite expressed PvTRAg38, from this noncultivable human malaria parasite. PvTRAg38 is highly immunogenic in humans and binds to host erythrocytes, and this binding is inhibited by the patient sera. This binding is also affected if host erythrocytes were pretreated with chymotrypsin. Here, Band 3 has been identified as the chymotrypsin-sensitive erythrocyte receptor for this parasite protein. Interaction of PvTRAg38 with Band 3 has been mapped to its three different ectodomains (loops 1, 3, and 6) exposed at the surface of the erythrocyte. The binding region of PvTRAg38 to Band3 has been mapped to its sequence, KWVQWKNDKIRSWLSSEW, present at amino acid positions 197–214. The recombinant PvTRAg38 was able to inhibit the parasite growth in in vitro Plasmodium falciparum culture probably by competing with the ligand(s) of this heterologous parasite for the erythrocyte Band 3 receptor. In conclusion, the host-parasite interaction at the molecular level is much more complicated than known so far and should be considered during the development of anti-malarial therapeutics. PMID:26149684

Tryptophan Cluster Protects Human γD-Crystallin from Ultraviolet Radiation-Induced Photoaggregation In Vitro

PubMed Central

Schafheimer, Nathaniel; King, Jonathan

2013-01-01

Exposure to ultraviolet radiation (UVR) is a significant risk factor for age-related cataract, a disease of the human lens and the most prevalent cause of blindness in the world. Cataract pathology involves protein misfolding and aggregation of the primary proteins of the lens, the crystallins. Human γD-crystallin (HγD-Crys) is a major γ-crystallin in the nucleus of the human lens. We report here analysis of UVR-induced damage to HγD-Crys in vitro. Irradiation of solutions of recombinant HγD-Crys with UVA/UVB light produced a rise in solution turbidity due to polymerization of the monomeric crystallins into higher molecular weight aggregates. A significant fraction of this polymerized protein was covalently linked. Photoaggregation of HγD-Crys required oxygen and its rate was protein concentration and UVR dose dependent. To investigate the potential roles of individual tryptophan residues in photoaggregation, triple W:F mutants of HγD-Crys were irradiated. Surprisingly, despite reducing UVR absorbing capacity, multiple W:F HγD-Crys mutant proteins photoaggregated more quickly and extensively than wild type. The results reported here are consistent with previous studies that postulated that an energy transfer mechanism between the highly conserved pairs of tryptophan residues in HγD-Crys could be protective against UVR-induced photodamage. PMID:23683003

Effect of acute tryptophan depletion on the response to controllable and uncontrollable noise stress.

PubMed

Richell, Rebecca A; Deakin, J F William; Anderson, Ian M

2005-02-01

Previous research provides evidence linking serotonin (5-hydroxytryptamine, 5-HT) with stress and depression. The controllable/uncontrollable (C/UC) stress paradigm aims to generate a state/condition, namely a feeling of lack of control in the context of a stressor, which might be an important factor in precipitating a negative mood state. Acute tryptophan depletion (ATD) is a technique that produces a decrease in central 5-HT levels in vivo. This study investigated the role of 5-HT in the behavioral response to a C/UC stress paradigm with ATD. Healthy adult volunteers were randomly assigned to receive either a TRP-supplemented (n = 15) or TRP-deficient (n = 13) amino acid drink. At 5 hours postdrink, volunteers were subjected to sessions of controllable and uncontrollable noise stress (100-dB white noise). Subjective ratings of mood were obtained before and after the interventions. Participants who received the tryptophan-depleting drink had greater self-report ratings of negative mood on visual analogue scales and the Profile of Mood States after the uncontrollable stress than did participants who received the balanced drink. The results suggest that 5-HT might play a role in providing resilience to uncontrollable stress. Additional studies with specific 5-HT pharmacologic probes will further clarify the results.

Chromatographic determination of harmalans in the urine of autistic children.

PubMed

Kałużna-Czaplińska, Joanna; Jóźwik-Pruska, Jagoda; Axt, Andrea

2017-09-01

This paper presents a new approach to autism - a complex and still enigmatic condition. We present the results of our preliminary research which was based on the detection of the hallucinogenic substance 6- (or 10-)methoxyharmalan in the urine samples of autistic children with the use of chromatographic methods. Additionally, we aim to describe the relationship between the level of tryptophan and harmalan, and the influence of supplementation on the level of this compound. We applied HPLC-UV/vis, HPLC-DAD and LC-MS in order to determine McIsaac's compound in the urine samples obtained from autistic children (n = 132) and healthy individuals (n = 10). The level of tryptophan was quantified with the use of GC-MS. Our research shows the presence of the McIsaac's compound in 110 samples of ASD children contrary to healthy children, where it was not found. No relationship between the level of tryptophan and 6-methoxyharmalan was noticed. The study shows a strong influence of melatonin supplementation on the presence of the McIsaac's compound. We believe that the results of our research can contribute to a better understanding of autism spectrum disorders. Moreover, our findings can form the basis for other studies focused on autism, eventually making it possible to understand its etiology. Copyright © 2017 John Wiley & Sons, Ltd.

Determining the binding affinities of phenolic compounds to proteins by quenching of the intrinsic tryptophan fluorescence.

PubMed

Rawel, Harshadrai M; Frey, Simone K; Meidtner, Karina; Kroll, Jürgen; Schweigert, Florian J

2006-08-01

The noncovalent binding of selected phenolic compounds (chlorogenic-, ferulic-, gallic acid, quercetin, rutin, and isoquercetin) to proteins (HSA, BSA, soy glycinin, and lysozyme) was studied by an indirect method applying the quenching of intrinsic tryptophan fluorescence. From the data obtained, the binding constants were calculated by nonlinear regression (one site binding; y = Bx/k + x). It has been reported that tannins inhibit human salivary amylase and that these complexes may reduce the development of cariogenic plaques. Further, amylase contains two tryptophan residues in its active site. Therefore, in a second part of the study involving 31 human subjects, evidence was sought for noncovalent interactions between the phenols of green tea and saliva proteins as measured by the fluorescence intensity. Amylase activity was determined before and after the addition of green tea to saliva of 31 subjects. Forty percent of the subjects showed an increase in amylase activity contrary to studies reporting only a decrease in activity. The interactions of tannin with amylase result in a decrease of its activity. It still remains to be elucidated why amylase does not react uniformly under conditions of applying green tea to saliva. Further, in terms of using phenols as caries inhibitors this finding should be of importance.

Bright ambient light conditions reduce the effect of tryptophan depletion in healthy females.

PubMed

Defrancesco, Michaela; Niederstätter, Harald; Parson, Walther; Kemmler, Georg; Hinterhuber, Hartmann; Marksteiner, Josef; Deisenhammer, Eberhard A

2013-11-30

Tryptophan depletion (TD) is an established method to influence the serotonergic system and mood. The purpose of this study was to examine the effect of TD under different ambient light conditions, measured through serotonin-associated plasma levels and a visual analog scale (VAS), on healthy females. Thirty-eight healthy female s-allele carriers of the serotonin transporter promoter gene (5-HTTLPR) were administered a TD under dim light conditions (75 lx). A sub-group of 8 participants repeated the procedure randomized in two additional light conditions (585 lx and 1530 lx respectively). Prior to, and 5h following administration of TD, various variables (serotonin-associated plasma levels, VAS) were measured. Due to not normal distributed data, non-parametric statistical tests were used. Overall analysis showed a significant mood lowering effect of TD. Moreover, TD decreased all measured serotonin-associated plasma levels significantly. Significant differences in varying light conditions were found for the VAS and plasma tryptophan, with the greatest effect of TD in the 75 lx condition. Results of our study showed an influence of even slight differences in ambient light intensity on the effect of TD concerning mood as well as on the serotonergic system. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Growth inhibitory effects of anthranilic acid and its derivatives against Legionella pneumophila.

PubMed

Sasaki, Takahide; Mizuguchi, Satoru; Honda, Kohsuke

2012-06-01

Legionella pneumophila is the principal etiologic agent of Legionnaires' disease. We found that the growth of L. pneumophila was markedly inhibited by its own cell lysate and the inhibitory effect was abolished by heat-treatment of the lysate. The genomic library of L. pneumophila was constructed in Escherichia coli and screened to determine the gene involved in the growth inhibition. A clone harboring the gene encoding anthranilate synthase (TrpE), which is involved in tryptophan biosynthesis, exhibited an inhibitory effect on the growth of L. pneumophila. Anthranilic acid exogenously added also exhibited antibacterial activity against L. pneumophila. A series of single-gene-knockout mutants of L. pneumophila lacking tryptophan synthesis genes were constructed and assessed for their susceptibility to anthranilic acid. Although the growth of mutants deficient in anthranilate phosphoribosyltransferase (TrpD) and N-(5'-phosphoribosyl)anthranilate isomerase (TrpF) was not affected by exogenous anthranilic acid, the indole-3-glycerophosphate synthase (TrpC) deficient mutant exhibited an increased susceptibility compared with the parent strain. These observations strongly indicate that 1-(2-carboxyphenylamino)-1'-deoxyribulose-5'-phosphate (CPADR-5'-P), which is an intermediate of tryptophan synthesis from anthranilic acid, is responsible for the growth inhibition of L. pneumophila. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Serotonergic neurotransmission and lapses of attention in children and adolescents with attention deficit hyperactivity disorder: availability of tryptophan influences attentional performance.

PubMed

Zepf, Florian D; Gaber, Tilman J; Baurmann, David; Bubenzer, Sarah; Konrad, Kerstin; Herpertz-Dahlmann, Beate; Stadler, Christina; Poustka, Fritz; Wöckel, Lars

2010-08-01

Deficiencies in serotonergic (5-HT) neurotransmission have frequently been linked to altered attention and memory processes. With attention deficit hyperactivity disorder (ADHD) being associated with impaired attention and working memory, this study investigated the effects of a diminished 5-HT turnover achieved by rapid tryptophan depletion (RTD) on attentional performance in children and adolescents with ADHD. Twenty-two male patients with ADHD (aged 9-15 yr) received the RTD procedure Moja-De and a tryptophan (Trp)-balanced placebo (Pla) in a randomized, double-blind, within-subject crossover design on two separate study days. Lapses of attention (LA) and phasic alertness (PA) were assessed within the test battery for attentional performance under depleted and sham-depleted conditions 120 (T1), 220 (T2) and 300 (T3) min after intake of RTD/Pla. At T1 there was a significant main effect for RTD, indicating more LA under intake of a Trp-balanced Pla compared to diminished 5-HT neurotransmission. For T2/T3 there were no such effects. PA was not affected by the factors RTD/Pla and time. Interactions of 5-HT with other neurotransmitters as possible underlying neurochemical processes could be subject to further investigations involving healthy controls as regards altered attentional performance in children and adolescents.

Improved Synthesis of 4-Cyanotryptophan and Other Tryptophan Analogues in Aqueous Solvent Using Variants of TrpB from Thermotoga maritima.

PubMed

Boville, Christina E; Romney, David K; Almhjell, Patrick J; Sieben, Michaela; Arnold, Frances H

2018-04-27

The use of enzymes has become increasingly widespread in synthesis as chemists strive to reduce their reliance on organic solvents in favor of more environmentally benign aqueous media. With this in mind, we previously endeavored to engineer the tryptophan synthase β-subunit (TrpB) for production of noncanonical amino acids that had previously been synthesized through multistep routes involving water-sensitive reagents. This enzymatic platform proved effective for the synthesis of analogues of the amino acid tryptophan (Trp), which are frequently used in pharmaceutical synthesis as well as chemical biology. However, certain valuable compounds, such as the blue fluorescent amino acid 4-cyanotryptophan (4-CN-Trp), could only be made in low yield, even at elevated temperature (75 °C). Here, we describe the engineering of TrpB from Thermotoga maritima that improved synthesis of 4-CN-Trp from 24% to 78% yield. Remarkably, although the final enzyme maintains high thermostability ( T 50 = 93 °C), its temperature profile is shifted such that high reactivity is observed at ∼37 °C (76% yield), creating the possibility for in vivo 4-CN-Trp production. The improvements are not specific to 4-CN-Trp; a boost in activity at lower temperature is also demonstrated for other Trp analogues.

Metabolic Profiling of Dendrobium officinale in Response to Precursors and Methyl Jasmonate

PubMed Central

Jiao, Chunyan; Song, Cheng; Zheng, Siyan; Zhu, Yingpeng; Jin, Qing; Cai, Yongping; Lin, Yi

2018-01-01

Alkaloids are the main active ingredients in the medicinal plant Dendrobium officinale. Based on the published genomic and transcriptomic data, a proposed terpenoid indole alkaloid (TIA) biosynthesis pathway may be present in D. officinale. In this study, protocorm-like bodies (PLBs) with a high-yielding production of alkaloids were obtained by the optimization of tryptophan, secologanin and methyl jasmonate (MeJA) treatment. The results showed that the total alkaloid content was 2.05 times greater than that of the control group when the PLBs were fed with 9 µM tryptophan, 6 µM secologanin and 100 µM MeJA after 36 days. HPLC analysis showed that strictosidine synthase (STR) activity also increased in the treated plants. A total of 78 metabolites were identified using gas chromatography-mass spectrometry (GC-MS) in combination with liquid chromatography-mass spectrometry (LC-MS) methods; 29 differential metabolites were identified according to the multivariate statistical analysis. Among them, carapanaubine, a kind of TIA, exhibited dramatically increased levels. In addition, a possible underlying process of the metabolic flux from related metabolism to the TIA biosynthetic pathway was enhanced. These results provide a comprehensive view of the metabolic changes related to alkaloid biosynthesis, especially TIA biosynthesis, in response to tryptophan, secologanin and MeJA treatment. PMID:29510516

Role of 5-HT5A receptors in the consolidation of memory.

PubMed

Gonzalez, Roberto; Chávez-Pascacio, Karla; Meneses, Alfredo

2013-09-01

5-HT5 receptor occurs in brain areas implicated in learning and memory. Hence, the effects (0.01-3.0 mg/kg) of SB-6995516 (a 5-HT5A receptor antagonist) in the associative learning task of autoshaping were studied. The results showed that post-training injection of SB-699551 decreased conditioned responses (CR) during short-term (STM; 1.5h; at 0.1mg/kg) and long-term memory (LTM; 24 h; at 3.0 mg/kg) relative to the vehicle animals. Moreover, considering that there are no selective 5-HT5A receptor agonists, next, diverse doses of the serotonin precursor l-tryptophan were studied during STM and LTM, showing that l-tryptophan (5-100mg/kg) facilitated performance, particularly at 50mg/kg. In interactions experiments, l-tryptophan (50 mg/kg) attenuated the impairment effect induced by SB-699551 (either 0.3 or 3.0 mg/kg). All together this evidence suggests that the blockade of 5-HT5A receptor appear to be able to impair STM and LTM (24 h), while its stimulation might facilitate it. Of course further investigation is necessary, meanly with selective 5-HT5A compounds are necessary. Copyright © 2013 Elsevier B.V. All rights reserved.

Interaction of amino acid-functionalized silver nanoparticles and Candida albicans polymorphs: A deep-UV fluorescence imaging study.

PubMed

Dojčilović, Radovan; Pajović, Jelena D; Božanić, Dušan K; Bogdanović, Una; Vodnik, Vesna V; Dimitrijević-Branković, Suzana; Miljković, Miona G; Kaščaková, Slavka; Réfrégiers, Matthieu; Djoković, Vladimir

2017-07-01

The interaction of the tryptophan functionalized Ag nanoparticles and live Candida albicans cells was studied by synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging at the DISCO beamline of Synchrotron SOLEIL. DUV imaging showed that incubation of the fungus with functionalized nanoparticles results in significant increase in the fluorescence signal. The analysis of the images revealed that the interaction of the nanoparticles with (pseudo)hyphae polymorphs of the diploid fungus was less pronounced than in the case of yeast cells or budding spores. The changes in the intensity of the fluorescence signals of the cells after incubation were followed in [327-353nm] and [370-410nm] spectral ranges that correspond to the fluorescence of tryptophan in non-polar and polar environment, respectively. As a consequence of the environmental sensitivity of the silver-tryptophan fluorescent nanoprobe, we were able to determine the possible accumulation sites of the nanoparticles. The analysis of the intensity decay kinetics showed that the photobleaching effects were more pronounced in the case of the functionalized nanoparticle treated cells. The results of time-integrated emission in the mentioned spectral ranges suggested that the nanoparticles penetrate the cells, but that the majority of the nanoparticles attach to the cells' surfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Depressive disorder and gastrointestinal dysfunction after myocardial infarct are associated with abnormal tryptophan-5-hydroxytryptamine metabolism in rats

PubMed Central

Liu, Chunyan; Wang, Yangang

2017-01-01

In this study, we investigated the relationship between tryptophan-5-hydroxytryptamine metabolism, depressive disorder, and gastrointestinal dysfunction in rats after myocardial infarction. Our goal was to elucidate the physiopathologic bases of somatic/psychiatric depression symptoms after myocardial infarction. A myocardial infarction model was established by permanent occlusion of the left anterior descending coronary artery. Depression-like behavior was evaluated using the sucrose preference test, open field test, and forced swim test. Gastric retention and intestinal transit were detected using the carbon powder labeling method. Immunohistochemical staining was used to detect indoleamine 2,3-dioxygenase expression in the hippocampus and ileum. High-performance liquid chromatography with fluorescence and ultraviolet detection determined the levels of 5-hydroxytryptamine, its precursor tryptophan, and its metabolite 5-hydroxyindoleacetic acid in the hippocampus, distal ileum, and peripheral blood. All data were analyzed using one-way analyses of variance. Three weeks after arterial occlusion, rats in the model group began to exhibit depression-like symptoms. For example, the rate of sucrose consumption was reduced, the total and central distance traveled in the open field test were reduced, and immobility time was increased, while swimming, struggling and latency to immobility were decreased in the forced swim test. Moreover, the gastric retention rate and gastrointestinal transit rate were increased in the model group. Expression of indoleamine 2,3-dioxygenase was increased in the hippocampus and ileum, whereas 5-hydroxytryptamine metabolism was decreased, resulting in lower 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels in the hippocampus and higher levels in the ileum. Depressive disorder and gastrointestinal dysfunction after myocardial infarction involve abnormal tryptophan-5-hydroxytryptamine metabolism, which may explain the somatic, cognitive, and psychiatric symptoms of depression commonly observed after myocardial infarction. Peripheral 5-hydroxytryptamine is an important substance in the gut-brain axis, and its abnormal metabolism is a critical finding after myocardial infarct. PMID:28212441

Depressive disorder and gastrointestinal dysfunction after myocardial infarct are associated with abnormal tryptophan-5-hydroxytryptamine metabolism in rats.

PubMed

Lu, Xiaofang; Wang, Yuefen; Liu, Chunyan; Wang, Yangang

2017-01-01

In this study, we investigated the relationship between tryptophan-5-hydroxytryptamine metabolism, depressive disorder, and gastrointestinal dysfunction in rats after myocardial infarction. Our goal was to elucidate the physiopathologic bases of somatic/psychiatric depression symptoms after myocardial infarction. A myocardial infarction model was established by permanent occlusion of the left anterior descending coronary artery. Depression-like behavior was evaluated using the sucrose preference test, open field test, and forced swim test. Gastric retention and intestinal transit were detected using the carbon powder labeling method. Immunohistochemical staining was used to detect indoleamine 2,3-dioxygenase expression in the hippocampus and ileum. High-performance liquid chromatography with fluorescence and ultraviolet detection determined the levels of 5-hydroxytryptamine, its precursor tryptophan, and its metabolite 5-hydroxyindoleacetic acid in the hippocampus, distal ileum, and peripheral blood. All data were analyzed using one-way analyses of variance. Three weeks after arterial occlusion, rats in the model group began to exhibit depression-like symptoms. For example, the rate of sucrose consumption was reduced, the total and central distance traveled in the open field test were reduced, and immobility time was increased, while swimming, struggling and latency to immobility were decreased in the forced swim test. Moreover, the gastric retention rate and gastrointestinal transit rate were increased in the model group. Expression of indoleamine 2,3-dioxygenase was increased in the hippocampus and ileum, whereas 5-hydroxytryptamine metabolism was decreased, resulting in lower 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels in the hippocampus and higher levels in the ileum. Depressive disorder and gastrointestinal dysfunction after myocardial infarction involve abnormal tryptophan-5-hydroxytryptamine metabolism, which may explain the somatic, cognitive, and psychiatric symptoms of depression commonly observed after myocardial infarction. Peripheral 5-hydroxytryptamine is an important substance in the gut-brain axis, and its abnormal metabolism is a critical finding after myocardial infarct.

Effects of tryptophan supplementation on cashmere fiber characteristics, serum tryptophan, and related hormone concentrations in cashmere goats.

PubMed

Ma, H; Zhang, W; Song, W H; Sun, P; Jia, Z H

2012-10-01

This study was designed to investigate the effects of tryptophan (Trp) supplementation on cashmere fiber characteristics and on serum Trp, melatonin (MEL), prolactin (PRL), insulin-like growth factor 1 (IGF-1), triiodothyronine (T3), and thyroxine (T4) concentrations in cashmere goats during the cashmere fast-growth period. Thirty-six Liaoning cashmere wether goats were stratified on the basis of body weight (28±0.8 kg) and assigned randomly to 1 of the following 4 rumen-protected Trp treatments: 0, 2.0, 4.0, and 6.0 g per goat per day. The experimental period lasted 137 d. Blood samples were collected monthly during the daytime (8:00 AM) and at night (8:00 PM). Tryptophan supplementation improved cashmere growth rates, cashmere weight, and body weight (P=0.001) and increased serum Trp levels, nighttime MEL concentrations, IGF-1, and T3 and T4 concentrations (P<0.05). Across the treatments and sampling months, a highly positive correlation between cashmere growth rate and nighttime serum MEL concentrations was observed (r=0.879, P=0.001). A moderately negative correlation between cashmere growth rates and serum PRL concentrations during the day and at night (rday=-0.645, P=0.007; rnight=-0.583, P=0.018) was observed. A moderately positive correlation between the cashmere growth rate and the daytime serum IGF-1 concentration (r=0.536, P=0.032) was observed, and no correlation was found between the cashmere growth rate and the other serum hormone concentrations. These data indicate that changes in serum concentrations of MEL, IGF-1, and PRL are related to cashmere growth in Liaoning cashmere goats during the cashmere fast-growth period. Under the experimental conditions of the current trial, we suggest that Trp may promote cashmere growth by increasing daytime IGF-1 and nighttime MEL secretion. Copyright © 2012 Elsevier Inc. All rights reserved.

Endophytic Bacterium Pseudomonas fluorescens RG11 May Transform Tryptophan to Melatonin and Promote Endogenous Melatonin Levels in the Roots of Four Grape Cultivars

PubMed Central

Ma, Yaner; Jiao, Jian; Fan, Xiucai; Sun, Haisheng; Zhang, Ying; Jiang, Jianfu; Liu, Chonghuai

2017-01-01

Endophytes have been verified to synthesize melatonin in vitro and promote abiotic stress-induced production of endogenous melatonin in grape (Vitis vinifera L.) roots. This study aimed to further characterize the biotransformation of tryptophan to melatonin in the endophytic bacterium Pseudomonas fluorescens RG11 and to investigate its capacity for enhancing endogenous melatonin levels in the roots of different grape cultivars. Using ultra performance liquid chromatography-tandem mass spectrometry combined with 15N double-labeled L-tryptophan as the precursor for melatonin, we detected isotope-labeled 5-hydroxytryptophan, serotonin, N-acetylserotonin, and melatonin, but tryptamine was not detected during the in vitro incubation of P. fluorescens RG11. Furthermore, the production capacity of these four compounds peaked during the exponential growth phase. RG11 colonization increased the endogenous levels of 5-hydroxytryptophan, N-acetylserotonin, and melatonin, but reduced those of tryptamine and serotonin, in the roots of the Red Globe grape cultivar under salt stress conditions. Quantitative real-time PCR revealed that RG11 reduced the transcription of grapevine tryptophan decarboxylase and serotonin N-acetyltransferase genes when compared to the un-inoculated control. These results correlated with decreased reactive oxygen species bursts and cell damage, which were alleviated by RG11 colonization under salt stress conditions. Additionally, RG11 promoted plant growth and enhanced the levels of endogenous melatonin in different grape cultivars. Intraspecific variation in the levels of melatonin precursors was found among four grape cultivars, and the associated root crude extracts appeared to significantly induce RG11 melatonin biosynthesis in vitro. Overall, this study provides useful information that enhances the existing knowledge of a potential melatonin synthesis pathway in rhizobacteria, and it reveals plant–rhizobacterium interactions that affect melatonin biosynthesis in plants subjected to abiotic stress conditions. PMID:28119731

Endophytic Bacterium Pseudomonas fluorescens RG11 May Transform Tryptophan to Melatonin and Promote Endogenous Melatonin Levels in the Roots of Four Grape Cultivars.

PubMed

Ma, Yaner; Jiao, Jian; Fan, Xiucai; Sun, Haisheng; Zhang, Ying; Jiang, Jianfu; Liu, Chonghuai

2016-01-01

Endophytes have been verified to synthesize melatonin in vitro and promote abiotic stress-induced production of endogenous melatonin in grape ( Vitis vinifera L.) roots. This study aimed to further characterize the biotransformation of tryptophan to melatonin in the endophytic bacterium Pseudomonas fluorescens RG11 and to investigate its capacity for enhancing endogenous melatonin levels in the roots of different grape cultivars. Using ultra performance liquid chromatography-tandem mass spectrometry combined with 15N double-labeled L -tryptophan as the precursor for melatonin, we detected isotope-labeled 5-hydroxytryptophan, serotonin, N -acetylserotonin, and melatonin, but tryptamine was not detected during the in vitro incubation of P. fluorescens RG11. Furthermore, the production capacity of these four compounds peaked during the exponential growth phase. RG11 colonization increased the endogenous levels of 5-hydroxytryptophan, N -acetylserotonin, and melatonin, but reduced those of tryptamine and serotonin, in the roots of the Red Globe grape cultivar under salt stress conditions. Quantitative real-time PCR revealed that RG11 reduced the transcription of grapevine tryptophan decarboxylase and serotonin N -acetyltransferase genes when compared to the un-inoculated control. These results correlated with decreased reactive oxygen species bursts and cell damage, which were alleviated by RG11 colonization under salt stress conditions. Additionally, RG11 promoted plant growth and enhanced the levels of endogenous melatonin in different grape cultivars. Intraspecific variation in the levels of melatonin precursors was found among four grape cultivars, and the associated root crude extracts appeared to significantly induce RG11 melatonin biosynthesis in vitro . Overall, this study provides useful information that enhances the existing knowledge of a potential melatonin synthesis pathway in rhizobacteria, and it reveals plant-rhizobacterium interactions that affect melatonin biosynthesis in plants subjected to abiotic stress conditions.

A laser desorption ionization/matrix-assisted laser desorption ionization target system applicable for three distinct types of instruments (LinTOF/curved field RTOF, LinTOF/RTOF and QqRTOF) with different performance characteristics from three vendors.

PubMed

Rados, Edita; Pittenauer, Ernst; Frank, Johannes; Varmuza, Kurt; Allmaier, Günter

2018-04-30

We have developed a target system which enables the use of only one target (i.e. target preparation set) for three different laser desorption ionization (LDI)/matrix-assisted laser desorption ionization (MALDI) mass spectrometric instruments. The focus was on analysing small biomolecules with LDI for future use of the system for the study of meteorite samples (carbonaceous chondrites) using devices with different mass spectrometric performance characteristics. Three compounds were selected due to their potential presence in meteoritic chondrites: tryptophan, 2-deoxy-d-ribose and triphenylene. They were prepared (with and without MALDI matrix, i.e. MALDI and LDI) and analysed with three different mass spectrometers (LinTOF/curved field RTOF, LinTOF/RTOF and QqRTOF). The ion sources of two of the instruments were run at high vacuum, and one at intermediate pressure. Two devices used a laser wavelength of 355 nm and one a wavelength of 337 nm. The developed target system operated smoothly with all devices. Tryptophan, 2-deoxy-d-ribose and triphenylene showed similar desorption/ionization behaviour for all instruments using the LDI mode. Interestingly, protonated tryptophan could be observed only with the LinTOF/curved field RTOF device in LDI and MALDI mode, while sodiated molecules were observed with all three instruments (in both ion modes). Deprotonated tryptophan was almost completely obscured by matrix ions in the MALDI mode whereas LDI yielded abundant deprotonated molecules. The presented target system allowed successful analyses of the three compounds using instruments from different vendors with only one preparation showing different analyser performance characteristics. The elemental composition with the QqRTOF analyser and the high-energy 20 keV collision-induced dissociation fragmentation will be important in identifying unknown compounds in chondrites. © 2018 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

Marker-assisted breeding for introgression of opaque-2 allele into elite maize inbred line BML-7.

PubMed

Krishna, M S R; Sokka Reddy, S; Satyanarayana, Sadam D V

2017-07-01

Improvement of quality protein maize (QPM) along with high content of lysine and tryptophan had foremost importance in maize breeding program. The efficient and easiest way of developing QPM hybrids was by backcross breeding in marker aided selection. Hence, the present investigation aimed at conversion of elite maize inbred line BML-7 into QPM line. CML-186 was identified to be a donor variety as it revealed high-quality polymorphism with BML-7 for opaque-2 gene specific marker umc1066. Non-QPM inbred line BML-7 was crossed with QPM donor CML-186 and produced F 1 followed by the development of BC 1 F 1 and BC 2 F 1 population. Foreground selection was carried out with umc1066 in F 1 , and selected plants were used for BC 1 F 1 and BC 2 F 1 populations. Two hundred plants were screened in both BC 1 F 1 and BC 2 F 1 population with umc1066 for foreground selection amino acid modifiers. Foreground selected plants for both opaque-2 and amino acid modifiers were screened for background selection for BML-7 genome. Recurrent parent genome (RPG) was calculated for BC 2 F 1 population plants. Two plants have shown with RPG 90-93% in two generation with back cross population. Two BC 2 F 2 populations resulted from marker recognized BC 2 F 1 individuals subjected toward foreground selection followed by tryptophan estimation. The tryptophan and lysine concentration was improved in all the plants. BC 2 F 2 lines developed from hard endosperm kernels were selfed for BC 2 F 2 lines and finest line was selected to illustrate the QPM version of BML-7, with 0.97% of tryptophan and 4.04% of lysine concentration in protein. Therefore, the QPM version of BML-7 line can be used for the development of single cross hybrid QPM maize version.

Indole-3-Acetic Acid Is Produced by Emiliania huxleyi Coccolith-Bearing Cells and Triggers a Physiological Response in Bald Cells.

PubMed

Labeeuw, Leen; Khey, Joleen; Bramucci, Anna R; Atwal, Harjot; de la Mata, A Paulina; Harynuk, James; Case, Rebecca J

2016-01-01

Indole-3-acetic acid (IAA) is an auxin produced by terrestrial plants which influences development through a variety of cellular mechanisms, such as altering cell orientation, organ development, fertility, and cell elongation. IAA is also produced by bacterial pathogens and symbionts of plants and algae, allowing them to manipulate growth and development of their host. They do so by either producing excess exogenous IAA or hijacking the IAA biosynthesis pathway of their host. The endogenous production of IAA by algae remains contentious. Using Emiliania huxleyi, a globally abundant marine haptophyte, we investigated the presence and potential role of IAA in algae. Homologs of genes involved in several tryptophan-dependent IAA biosynthesis pathways were identified in E. huxleyi. This suggests that this haptophyte can synthesize IAA using various precursors derived from tryptophan. Addition of L-tryptophan to E. huxleyi stimulated IAA production, which could be detected using Salkowski's reagent and GC × GC-TOFMS in the C cell type (coccolith bearing), but not in the N cell type (bald). Various concentrations of IAA were exogenously added to these two cell types to identify a physiological response in E. huxleyi. The N cell type, which did not produce IAA, was more sensitive to it, showing an increased variation in cell size, membrane permeability, and a corresponding increase in the photosynthetic potential quantum yield of Photosystem II (PSII). A roseobacter (bacteria commonly associated with E. huxleyi) Ruegeria sp. R11, previously shown to produce IAA, was co-cultured with E. huxleyi C and N cells. IAA could not be detected from these co-cultures, and even when stimulated by addition of L-tryptophan, they produced less IAA than axenic C type culture similarly induced. This suggests that IAA plays a novel role signaling between different E. huxleyi cell types, rather than between a bacteria and its algal host.

Competitive binding effects on surface-enhanced Raman scattering of peptide molecules

NASA Astrophysics Data System (ADS)

Seballos, Leo; Richards, Nicole; Stevens, Daniel J.; Patel, Mira; Kapitzky, Laura; Lokey, Scott; Millhauser, Glenn; Zhang, Jin Z.

2007-10-01

Surface enhanced Raman scattering (SERS) has been conducted on tryptophan (W), proline (P) and tyrosine (Y) containing peptides that include W-P-Y, Y-P-W, W-P-P-P-Y, Y-P-P-P-W, W-P-P-P-P-P-Y, and Y-P-P-P-P-P-W to gain insight into molecular binding behavior on a metal substrate to eventually apply in protein SERS detection. The peptides are shown to bind through the molecule's carboxylic end, but the strong affinity of the tryptophan residue to the substrate surface, in conjunction with its large polarizability, dominates each molecule's SERS signal with the strong presence of its ring modes in all samples. These results are important for understanding SERS of protein molecules.

Folding mechanism of β-hairpin trpzip2: heterogeneity, transition state and folding pathways.

PubMed

Xiao, Yi; Chen, Changjun; He, Yi

2009-06-22

We review the studies on the folding mechanism of the beta-hairpin tryptophan zipper 2 (trpzip2) and present some additional computational results to refine the picture of folding heterogeneity and pathways. We show that trpzip2 can have a two-state or a multi-state folding pattern, depending on whether it folds within the native basin or through local state basins on the high-dimensional free energy surface; Trpzip2 can fold along different pathways according to the packing order of tryptophan pairs. We also point out some important problems related to the folding mechanism of trpzip2 that still need clarification, e.g., a wide distribution of the computed conformations for the transition state ensemble.

Mass energy-absorption coefficients and average atomic energy-absorption cross-sections for amino acids in the energy range 0.122-1.330 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

More, Chaitali V., E-mail: chaitalimore89@gmail.com; Lokhande, Rajkumar M.; Pawar, Pravina P., E-mail: pravinapawar4@gmail.com

Mass attenuation coefficients of amino acids such as n-acetyl-l-tryptophan, n-acetyl-l-tyrosine and d-tryptophan were measured in the energy range 0.122-1.330 MeV. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The measured attenuation coefficient values were then used to determine the mass energy-absorption coefficients (σ{sub a,en}) and average atomic energy-absorption cross sections (μ{sub en}/ρ) of the amino acids. Theoretical values were calculated based on XCOM data. Theoretical and experimental values are found to be in good agreement.

Modified Carbon Nanotube Paste Electrode for Voltammetric Determination of Carbidopa, Folic Acid, and Tryptophan

PubMed Central

Esfandiari Baghbamidi, Sakineh; Beitollahi, Hadi; Karimi-Maleh, Hassan; Soltani-Nejad, Somayeh; Soltani-Nejad, Vahhab; Roodsaz, Sara

2012-01-01

A simple and convenient method is described for voltammetric determination of carbidopa (CD), based on its electrochemical oxidation at a modified multiwall carbon nanotube paste electrode. Under optimized conditions, the proposed method exhibited acceptable analytical performances in terms of linearity (over the concentration range from 0.1 to 700.0 μM), detection limit (65.0 nM), and reproducibility (RSD = 2.5%) for a solution containing CD. Also, square wave voltammetry (SWV) was used for simultaneous determination of CD, folic acid (FA), and tryptophan (TRP) at the modified electrode. To further validate its possible application, the method was used for the quantification of CD, FA, and TRP in urine samples. PMID:22666634

Investigation of tryptophan-NADH interactions in live human cells using three-photon fluorescence lifetime imaging and Förster resonance energy transfer microscopy

NASA Astrophysics Data System (ADS)

Jyothikumar, Vinod; Sun, Yuansheng; Periasamy, Ammasi

2013-06-01

A method to investigate the metabolic activity of intracellular tryptophan (TRP) and coenzyme-NADH using three-photon (3P) fluorescence lifetime imaging (FLIM) and Förster resonance energy transfer (FRET) is presented. Through systematic analysis of FLIM data from tumorigenic and nontumorigenic cells, a statistically significant decrease in the fluorescence lifetime of TRP was observed in response to the increase in protein-bound NADH as cells were treated with glucose. The results demonstrate the potential use of 3P-FLIM-FRET as a tool for label-free screening of the change in metabolic flux occurring in human diseases or other clinical conditions.

Mapping hydration dynamics around a protein surface

PubMed Central

Zhang, Luyuan; Wang, Lijuan; Kao, Ya-Ting; Qiu, Weihong; Yang, Yi; Okobiah, Oghaghare; Zhong, Dongping

2007-01-01

Protein surface hydration is fundamental to its structure and activity. We report here the direct mapping of global hydration dynamics around a protein in its native and molten globular states, using a tryptophan scan by site-specific mutations. With 16 tryptophan mutants and in 29 different positions and states, we observed two robust, distinct water dynamics in the hydration layer on a few (≈1–8 ps) and tens to hundreds of picoseconds (≈20–200 ps), representing the initial local relaxation and subsequent collective network restructuring, respectively. Both time scales are strongly correlated with protein's structural and chemical properties. These results reveal the intimate relationship between hydration dynamics and protein fluctuations and such biologically relevant water–protein interactions fluctuate on picosecond time scales. PMID:18003912

Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L.

1994-06-01

A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37more » refs., 9 figs., 5 tabs.« less

Spectroscopie pompe-sonde pour la détection de bioaérosols

NASA Astrophysics Data System (ADS)

Guyon, L.; Courvoisier, F.; Wood, V.; Boutou, V.; Bartelt, A.; Roth, M.; Rabitz, H.; Wolf, J. P.

2006-10-01

La fluorescence du Tryptophane excité par une impulsion ultra-brève à 270 nm peut être diminuée d'un facteur deux par une seconde impulsion à 800 nm, à l'aide d'un dispositif pompe-sonde. Cette décroissance est aussi observée pour les bactéries vivantes, dont le Tryptophane est l'un des fluorophores, tandis qu'aucune décroissance n'est observée pour d'autres molécules organiques comme le naphtalène ou le gazole, malgré des spectres d'absorption et de fluorescence similaires. Cette différence remarquable est très prometteuse pour la distinction d'aérosols biologiques et organiques.

Premenstrual syndrome - self-care

MedlinePlus

PMS - self-care; Premenstrual dysphoric disorder - self-care ... Your health care provider may recommend that you take vitamins or supplements. Vitamin B6, calcium, and magnesium may be recommended. Tryptophan ...

5-HTP

MedlinePlus

5-HTP (5-Hydroxytryptophan) is a chemical by-product of the protein building block L-tryptophan. It is also produced commercially from the seeds of an African plant known as Griffonia simplicifolia ...

Multi-spectroscopic investigation on the complexation of tetracycline with dissolved organic matter derived from algae and macrophyte.

PubMed

Bai, Leilei; Zhao, Zhen; Wang, Chunliu; Wang, Changhui; Liu, Xin; Jiang, Helong

2017-11-01

Interactions of antibiotics with algae-derived dissolved organic matter (ADOM) and macrophyte-derived dissolved organic matter (MDOM) are of vital importance to the transport and ecotoxicity of antibiotics in eutrophic freshwater lakes. Multi-spectroscopic techniques were used to investigate the complexation of tetracycline (TTC) with ADOM and MDOM collected from Lake Taihu (China). The 3 fluorescent components, tyrosine-, tryptophan-, and humic-like component, were identified by excitation emission matrix spectra with parallel factor analysis. Their fluorescence was quenched at different degree by TTC titration through static quenching. The complexation of TTC induced conformational changes in DOM fractions. Synchronous fluorescence spectra combined with two dimensional correlation spectroscopy further suggested that the formation of TTC-DOM complexes occurred on the sequential order of tryptophan-like→tyrosine-like→humic-like component. The effective quenching constants of tryptophan- and tyrosine-like component were similar, higher than those of humic-like component. The strong binding ability and abundant content of protein-like substances indicated their prominent role in the TTC-DOM complexation. Fourier transform infrared spectroscopy further revealed that the heterogeneous functional groups, including amide I and II, aromatics, and aliphatics, were responsible for the complexation. These results highlight the significant impact of the overgrowth of algae and macrophyte on the environmental behavior of antibiotics in waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tryptophan and Non-Tryptophan Fluorescence of the Eye Lens Proteins Provides Diagnostics of Cataract at the Molecular Level

PubMed Central

Gakamsky, Anna; Duncan, Rory R.; Howarth, Nicola M.; Dhillon, Baljean; Buttenschön, Kim K.; Daly, Daniel J.; Gakamsky, Dmitry

2017-01-01

The chemical nature of the non-tryptophan (non-Trp) fluorescence of porcine and human eye lens proteins was identified by Mass Spectrometry (MS) and Fluorescence Steady-State and Lifetime spectroscopy as post-translational modifications (PTM) of Trp and Arg amino acid residues. Fluorescence intensity profiles measured along the optical axis of human eye lenses with age-related nuclear cataract showed increasing concentration of fluorescent PTM towards the lens centre in accord with the increased optical density in the lens nucleolus. Significant differences between fluorescence lifetimes of “free” Trp derivatives hydroxytryptophan (OH-Trp), N-formylkynurenine (NFK), kynurenine (Kyn), hydroxykynurenine (OH-Kyn) and their residues were observed. Notably, the lifetime constants of these residues in a model peptide were considerably greater than those of their “free” counterparts. Fluorescence of Trp, its derivatives and argpyrimidine (ArgP) can be excited at the red edge of the Trp absorption band which allows normalisation of the emission spectra of these PTMs to the fluorescence intensity of Trp, to determine semi-quantitatively their concentration. We show that the cumulative fraction of OH-Trp, NFK and ArgP emission dominates the total fluorescence spectrum in both emulsified post-surgical human cataract protein samples, as well as in whole lenses and that this correlates strongly with cataract grade and age. PMID:28071717

Ontogeny of brain and blood serotonin levels in 5-HT receptor knockout mice: potential relevance to the neurobiology of autism.

PubMed

Janusonis, Skirmantas; Anderson, George M; Shifrovich, Ilya; Rakic, Pasko

2006-11-01

The most consistent neurochemical finding in autism has been elevated group mean levels of blood platelet 5-hydroxytryptamine (5-HT, serotonin). The origin and significance of this platelet hyperserotonemia remain poorly understood. The 5-HT(1A) receptor plays important roles in the developing brain and is also expressed in the gut, the main source of platelet 5-HT. Post-natal tissue levels of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan were examined in the brain, duodenum and blood of 5-HT(1A) receptor-knockout and wild-type mice. At 3 days after birth, the knockout mice had lower mean brain 5-HT levels and normal mean platelet 5-HT levels. Also, at 3 days after birth, the mean tryptophan levels in the brain, duodenum and blood of the knockout mice were around 30% lower than those of the wild-type mice. By 2 weeks after birth, the mean brain 5-HT levels of the knockout mice normalized, but their mean platelet 5-HT levels became 24% higher than normal. The possible causes of these dynamic shifts were explored by examining correlations between central and peripheral levels of 5-HT, 5-HIAA and tryptophan. The results are discussed in relation to the possible role of 5-HT in the ontogeny of autism.

Effects of tryptophan depletion on reactive aggression and aggressive decision-making in young people with ADHD.

PubMed

Kötting, W F; Bubenzer, S; Helmbold, K; Eisert, A; Gaber, T J; Zepf, F D

2013-08-01

The neurotransmitter serotonin (5-HT) has been linked to the underlying biological processes related to aggressive behaviour. However, only a few studies on this subject involving young people have been published so far. We aimed to investigate the effects of acute tryptophan depletion (ATD) on reactive aggression and decision-time for aggressive responses in a sample of young people with Attention deficit hyperactivity disorder (n = 20), a population at risk for aggressive behaviour. The study design was a double-blind within-subject crossover design. Aggression was assessed using a Point subtraction aggression game (PSAG) with high (HP) and low provocation (LP) trials 2.5 h after the intake of ATD and a tryptophan-balanced control condition. A chi-square comparison was used to identify the effect of ATD on increased aggression after LP. Boys were more likely to respond with an increased aggressive response after HP under ATD as represented by an increased relative risk and odds ratios. Girls had a higher relative risk than boys of an increased point subtraction under ATD after LP. No significant gender differences in decision-time were detected. An effect of ATD on increased aggression was found in the whole sample after LP. Research involving larger samples is needed to confirm the present preliminary findings. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Better Understanding of Protein Structure and Function by the Synthesis and Incorporation of Selenium- and Tellurium Containing Tryptophan Analogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helmey, Sherif Samir; Rice, Ambrose Eugene; Hatch, Duane Michael

Unnatural heavy metal-containing amino acid analogs have shown to be very important in the analysis of protein structure, using methods such as X-ray crystallography, mass spectroscopy, and NMR spectroscopy. Synthesis and incorporation of selenium-containing methionine analogs has already been shown in the literature however with some drawbacks due to toxicity to host organisms. Thus synthesis of heavy metal tryptophan analogs should prove to be more effective since the amino acid tryptophan is naturally less abundant in many proteins. For example, bioincorporation of β-seleno[3,2-b]pyrrolyl-L-alanine ([4,5]SeTrp) and β-selenolo[2,3-b]pyrrolyl-L-alanine ([6,7]SeTrp) has been shown in the following proteins without structural or catalytic perturbations: humanmore » annexin V, barstar, and dihydrofolate reductase. The reported synthesis of these Se-containing analogs is currently not efficient for commercial purposes. Thus a more efficient, concise, high-yield synthesis of selenotryptophan, as well as the corresponding, tellurotryptophan, will be necessary for wide spread use of these unnatural amino acid analogs. This research will highlight our progress towards a synthetic route of both [6,7]SeTrp and [6,7]TeTrp, which ultimately will be used to study the effect on the catalytic activity of Lignin Peroxidase (LiP).« less

The damaging effect of UV-C irradiation on lens alpha-crystallin.

PubMed

Fujii, Noriko; Uchida, Hiroki; Saito, Takeshi

2004-11-02

To evaluate the effect of UV-C irradiation on the structural properties of alpha-crystallin and its chaperone activity. alpha- and betaL-crystallins were isolated from bovine lenses using gel chromatography. The purified alpha-crystallin was subjected to UV-C irradiation (254 nm; 1, 2, 5, 10, 20, 50 J/cm2). We measured the tryptophan fluorescence, circular dichroism (CD) spectroscopy in the far UV, and the chaperone activity of both irradiated and non-irradiated alpha-crystallin. The tryptophan fluorescence of alpha-crystallin decreased, whereas the N-formylkynurenine fluorescence increased markedly with increasing doses of UV-C irradiation. Both the oxidation of Met1 and the racemization of Asp151 of alphaA-crystallin increased at a dose of 1-2 J/cm2 and then gradually decreased. The CD spectrum showed that the secondary structure of alpha-crystallin altered with increasing radiation dose, and almost all of the beta-sheet structure was lost at doses above 50 J/cm2. The chaperone activity of alpha-crystallin irradiated with doses under 5 J/cm2 remained intact. However, it was reduced to only 40% after irradiation at 10 J/cm2. Our study suggests that photo-oxidation of tryptophan residues in alpha-crystallin may be one of the events that affects the three-dimensional packing array and chaperone activity of this lens protein.

Effect of High Dietary Tryptophan on Intestinal Morphology and Tight Junction Protein of Weaned Pig.

PubMed

Tossou, Myrlene Carine B; Liu, Hongnan; Bai, Miaomiao; Chen, Shuai; Cai, Yinghua; Duraipandiyan, Veeramuthu; Liu, Hongbin; Adebowale, Tolulope O; Al-Dhabi, Naif Abdullah; Long, Lina; Tarique, Hussain; Oso, Abimbola O; Liu, Gang; Yin, Yulong

2016-01-01

Tryptophan (Trp) plays an essential role in pig behavior and growth performances. However, little is known about Trp's effects on tight junction barrier and intestinal health in weaned pigs. In the present study, twenty-four (24) weaned pigs were randomly assigned to one of the three treatments with 8 piglets/treatments. The piglets were fed different amounts of L-tryptophan (L-Trp) as follows: 0.0%, 0.15, and 0.75%, respectively, named zero Trp (ZTS), low Trp (LTS), and high Trp (HTS), respectively. No significant differences were observed in average daily gain (ADG), average daily feed intake (ADFI), and gain: feed (G/F) ratio between the groups. After 21 days of the feeding trial, results showed that dietary Trp significantly increased (P < 0.05) crypt depth and significantly decreased (P < 0.05) villus height to crypt depth ratio (VH/CD) in the jejunum of pig fed HTS. In addition, pig fed HTS had higher (P < 0.05) serum diamine oxidase (DAO) and D-lactate. Furthermore, pig fed HTS significantly decreased mRNA expression of tight junction proteins occludin and ZO-1 but not claudin-1 in the jejunum. The number of intraepithelial lymphocytes and goblet cells were not significantly different (P > 0.05) between the groups. Collectively, these data suggest that dietary Trp supplementation at a certain level (0.75%) may negatively affect the small intestinal structure in weaned pig.

Immune biomarkers in older adults: Role of physical activity.

PubMed

Valdiglesias, Vanessa; Sánchez-Flores, María; Maseda, Ana; Lorenzo-López, Laura; Marcos-Pérez, Diego; López-Cortón, Ana; Strasser, Barbara; Fuchs, Dietmar; Laffon, Blanca; Millán-Calenti, José C; Pásaro, Eduardo

2017-01-01

Aging is associated with a decline in the normal functioning of the immune system. Several studies described the relationship between immunological alterations, including immunosenescence and inflammation, and aging or age-related outcomes, such as sarcopenia, depression, and neurodegenerative disorders. Physical activity is known to improve muscle function and to exert a number of benefits on older adult health, including reduced risk for heart and metabolic system chronic diseases. However, the positive influence of physical activity on the immune system has not been elucidated. In order to shed light on the role of physical activity in immune responses of older individuals, a number of immunological parameters comprising % lymphocyte subsets (CD3 + , CD4 + , CD8 + , CD19 + , and CD16 + 56 + ) and serum levels of neopterin and tryptophan metabolism products were evaluated in peripheral blood samples of older adults performing normal (N = 170) or reduced (N = 89) physical activity. In addition, the potential influence of other clinical and epidemiological factors was also considered. Results showed that subjects with reduced physical activity displayed significantly higher levels of CD4 + /CD8 + ratio, kynurenine/tryptophan ratio, and serum neopterin, along with lower %CD19 + cells and tryptophan concentrations. Further, some immunological biomarkers were associated with cognitive impairment and functional status. These data contribute to reinforce the postulation that physical activity supports healthy aging, particularly by helping to protect the immunological system from aging-related changes.

Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene.

PubMed

Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

2014-05-01

A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π-π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2-12.9 mM, 0.5-110 μM, and 10-1000 μM, with the detection limits (S/N=3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Trehalose induced structural modulation of Bovine Serum Albumin at ambient temperature.

PubMed

Das, Ahana; Basak, Pijush; Pattanayak, Rudradip; Kar, Turban; Majumder, Rajib; Pal, Debadrita; Bhattacharya, Anindita; Bhattacharyya, Maitree; Banik, Samudra Prosad

2017-12-01

Trehalose is a well-known protein stabilizing osmolyte. The present study has been designed to understand the interaction of trehalose with BSA at ambient temperature. Steady state fluorescence and life-time analysis along with CD, DLS and ITC have been employed to show that trehalose causes surface-associated structural perturbation of BSA to promote its compaction. Trehalose at 0.1M concentration resulted in increased solvent exposure of one of the two tryptophans of BSA with a 5nm redshift in emission and enhanced susceptibility to acrylamide quenching with an increase in K SV from 2.61M -1 to 5.16M -1 . 0.5M trehalose resulted in reduced accessibility of tryptophan and destabilization of ANS binding (Forster radius increased from 24Å to 27.36Å for tryptophan-ANS FRET) indicating shielding of BSA in trehalose matrix. Simultaneously, there was compaction of BSA as shown by increased alpha-helicity from 45.85% to 48.81%, decreased thioflavin-T binding and reduction in hydrodynamic radius from 9.69nm to 6.59nm. Trehalose induced solution viscosity resulted in significant decrease in binding affinity of BSA towards curcumin and resveratrol. The results are in unison with the preferential exclusion and vitrification models to explain protein stabilization by trehalose and also points at the structure-function trade-off of proteins in presence of trehalose. Copyright © 2017 Elsevier B.V. All rights reserved.

Maternal dietary tryptophan deficiency alters cardiorespiratory control in rat pups.

PubMed

Penatti, Eliana M; Barina, Alexis E; Raju, Sharat; Li, Aihua; Kinney, Hannah C; Commons, Kathryn G; Nattie, Eugene E

2011-02-01

Malnutrition during pregnancy adversely affects postnatal forebrain development; its effect upon brain stem development is less certain. To evaluate the role of tryptophan [critical for serotonin (5-HT) synthesis] on brain stem 5-HT and the development of cardiorespiratory function, we fed dams a diet ∼45% deficient in tryptophan during gestation and early postnatal life and studied cardiorespiratory variables in the developing pups. Deficient pups were of normal weight at postnatal day (P)5 but weighed less than control pups at P15 and P25 (P < 0.001) and had lower body temperatures at P15 (P < 0.001) and P25 (P < 0.05; females only). Oxygen consumption (Vo(2)) was unaffected. At P15, deficient pups had an altered breathing pattern and slower heart rates. At P25, they had significantly lower ventilation (Ve) and Ve-to-Vo(2) ratios in both air and 7% CO(2). The ventilatory response to CO(2) (% increase in Ve/Vo(2)) was significantly increased at P5 (males) and reduced at P15 and P25 (males and females). Deficient pups had 41-56% less medullary 5-HT (P < 0.01) compared with control pups, without a difference in 5-HT neuronal number. These data indicate important interactions between nutrition, brain stem physiology, and age that are potentially relevant to understanding 5-HT deficiency in the sudden infant death syndrome.

Effects of tryptophan depletion on the performance of an iterated Prisoner's Dilemma game in healthy adults.

PubMed

Wood, Richard M; Rilling, James K; Sanfey, Alan G; Bhagwagar, Zubin; Rogers, Robert D

2006-05-01

Adaptive social behavior often necessitates choosing to cooperate with others for long-term gains at the expense of noncooperative behaviors giving larger immediate gains. Although little is know about the neural substrates that support cooperative over noncooperative behaviors, recent research has shown that mutually cooperative behavior in the context of a mixed-motive game, the Prisoner's Dilemma (PD), is associated with increased neural activity within reinforcement circuitry. Other research attests to a role for serotonin in the modulation of social behavior and in reward processing. In this study, we used a within-subject, crossover, double-blind design to investigate performance of an iterated, sequential PD game for monetary reward by healthy human adult participants following ingestion of an amino-acid drink that either did (T+) or did not (T-) contain l-tryptophan. Tryptophan depletion produced significant reductions in the level of cooperation shown by participants when playing the game on the first, but not the second, study days. This effect was accompanied by a significantly diminished probability of cooperative responding given previous mutually cooperative behavior. These data suggest that serotonin plays a significant role in the acquisition of socially cooperative behavior in human adult participants, and suggest novel hypotheses concerning the serotonergic modulation of reward information in socially cooperative behavior in both health and psychiatric illness.

Functional and conformational transitions of mevalonate diphosphate decarboxylase from Bacopa monniera.

PubMed

Abbassi, Shakeel; Patel, Krunal; Khan, Bashir; Bhosale, Siddharth; Gaikwad, Sushama

2016-02-01

Functional and conformational transitions of mevalonate diphosphate decarboxylase (MDD), a key enzyme of mevalonate pathway in isoprenoid biosynthesis, from Bacopa monniera (BmMDD), cloned and overexpressed in Escherichia coli were studied under thermal, chemical and pH-mediated denaturation conditions using fluorescence and Circular dichroism spectroscopy. Native BmMDD is a helix dominant structure with 45% helix and 11% sheets and possesses seven tryptophan residues with two residues exposed on surface, three residues partially exposed and two situated in the interior of the protein. Thermal denaturation of BmMDD causes rapid structural transitions at and above 40°C and transient exposure of hydrophobic residues at 50°C, leading to aggregation of the protein. An acid induced molten globule like structure was observed at pH 4, exhibiting altered but compact secondary structure, distorted tertiary structure and exposed hydrophobic residues. The molten globule displayed different response at higher temperature and similar response to chemical denaturation as compared to the native protein. The surface tryptophans have predominantly positively charged amino acids around them, as indicated by higher KSV for KI as compared to that for CsCl. The native enzyme displayed two different lifetimes, τ1 (1.203±0.036 ns) and τ2 (3.473±0.12 ns) indicating two populations of tryptophan. Copyright © 2015 Elsevier B.V. All rights reserved.

Niacin metabolism and indoleamine 2,3-dioxygenase activation in malnourished patients with flaky paint dermatosis.

PubMed

Maltos, André Luiz; Portari, Guilherme Vannucchi; Moraes, Giselle Vanessa; Monteiro, Marina Casteli Rodrigues; Vannucchi, Helio; da Cunha, Daniel Ferreira

2015-06-01

Flaky paint dermatosis, characterized by extensive, often bilateral areas of flaking and pigmentation, mostly in sun unexposed areas is considered a feature of kwashiorkor in both children and adults, and must be differentiated from other dermatosis, including chapped and xerotica skin, and pellagra. In this case series we provide evidence that malnourished patients with flaky paint dermatosis and infection/inflammation shown laboratory data suggestive of indoleamine 2,3-dioxygenase (IDO) activation, besides decreased urinary excretion of N1-methylnicotinamide (N1 MN), a marker of pellagra. We study nine adult patients showing flaky paint dermatosis and clinical features of infection or inflammation, and increased serum C-reactive protein, characteristic of the presence of acute phase response syndrome. As a group, they had low or deficient urinary N1 MN excretion (0.52 ± 0.39 mg/g creatinine) compatible with pellagra. They also showed low serum tryptophan levels (<29 μmol/L) and a serum kynurenine/tryptophan ratio higher than 0.04, suggesting increased IDO expression and increase in the tryptophan oxidation. Findings suggest that some patients with flaky paint dermatosis showed laboratory data suggestive of IDO activation, besides decreased N1 MN urinary excretion. Taken together, the data support the idea that flaky paint dermatosis could be a skin manifestation of niacin deficiency. Copyright © 2015 Elsevier Inc. All rights reserved.

The role of serotonin in nonnormative risky choice: the effects of tryptophan supplements on the "reflection effect" in healthy adult volunteers.

PubMed

Murphy, Susannah E; Longhitano, Carlo; Ayres, Rachael E; Cowen, Philip J; Harmer, Catherine J; Rogers, Robert D

2009-09-01

Risky decision-making involves weighing good and bad outcomes against their probabilities in order to determine the relative values of candidate actions. Although human decision-making sometimes conforms to rational models of how this weighting is achieved, irrational (or nonnormative) patterns of risky choice, including shifts between risk-averse and risk-seeking choices involving equivalent-value gambles (the "reflection effect"), are frequently observed. In the present experiment, we investigated the role of serotonin in decision-making under conditions of uncertainty. Fifteen healthy adult volunteers received a treatment of 3 g per day of the serotonin precursor, tryptophan, in the form of dietary supplements over a 14-day period, whereas 15 age- and IQ-matched control volunteers received a matched placebo substance. At test, all participants completed a risky decision-making task involving a series of choices between two simultaneously presented gambles, differing in the magnitude of their possible gains, the magnitude of their possible losses, and the probabilities with which these outcomes were delivered. Tryptophan supplements were associated with alterations in the weighting of gains and small losses perhaps reflecting reduced loss-aversion, and a marked and significant diminution of the reflection effect. We conclude that serotonin activity plays a significant role in nonnormative risky decision-making under conditions of uncertainty.

A single-run liquid chromatography mass spectrometry method to quantify neuroactive kynurenine pathway metabolites in rat plasma.

PubMed

Orsatti, Laura; Speziale, Roberto; Orsale, Maria Vittoria; Caretti, Fulvia; Veneziano, Maria; Zini, Matteo; Monteagudo, Edith; Lyons, Kathryn; Beconi, Maria; Chan, Kelvin; Herbst, Todd; Toledo-Sherman, Leticia; Munoz-Sanjuan, Ignacio; Bonelli, Fabio; Dominguez, Celia

2015-03-25

Neuroactive metabolites in the kynurenine pathway of tryptophan catabolism are associated with neurodegenerative disorders. Tryptophan is transported across the blood-brain barrier and converted via the kynurenine pathway to N-formyl-L-kynurenine, which is further degraded to L-kynurenine. This metabolite can then generate a group of metabolites called kynurenines, most of which have neuroactive properties. The association of tryptophan catabolic pathway alterations with various central nervous system (CNS) pathologies has raised interest in analytical methods to accurately quantify kynurenines in body fluids. We here describe a rapid and sensitive reverse-phase HPLC-MS/MS method to quantify L-kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxy-L-kynurenine (3HK) and anthranilic acid (AA) in rat plasma. Our goal was to quantify these metabolites in a single run; given their different physico-chemical properties, major efforts were devoted to develop a chromatography suitable for all metabolites that involves plasma protein precipitation with acetonitrile followed by chromatographic separation by C18 RP chromatography, detected by electrospray mass spectrometry. Quantitation range was 0.098-100 ng/ml for 3HK, 9.8-20,000 ng/ml for KYN, 0.49-1000 ng/ml for KYNA and AA. The method was linear (r>0.9963) and validation parameters were within acceptance range (calibration standards and QC accuracy within ±30%). Copyright © 2015 Elsevier B.V. All rights reserved.

Spectroscopic properties and conformational stability of Concholepas concholepas hemocyanin.

PubMed

Idakieva, Krassimira; Nikolov, Peter; Chakarska, Irena; Genov, Nicolay; Shnyrov, Valery L

2008-01-01

The structure in solution and conformational stability of the hemocyanin from the Chilean gastropod mollusk Concholepas concholepas (CCH) and its structural subunits, CCH-A and CCH-B, were studied using fluorescence spectroscopy and differential scanning calorimetry (DSC). The fluorescence properties of the oxygenated and apo-form (copper-deprived) of the didecamer and its subunits were characterized. Besides tryptophan residues buried in the hydrophobic interior of the protein molecule also exposed fluorophores determine the fluorescence emission of the oxy- and apo-forms of the investigated hemocyanins. The copper-dioxygen system at the binuclear active site quenches the tryptophan emission of the oxy-forms of CCH and its subunits. The removal of this system increases the fluorescence quantum yield and causes structural rearrangement of the microenvironment of the emitting tryptophan residues in the respective apo-forms. Time-resolved fluorescence measurements show that the oxygenated and copper-deprived forms of the CCH and its subunits exist in different conformations. The thermal denaturation of the hemocyanin is an irreversible process, under kinetic control. A successive annealing procedure was applied to obtain the experimental deconvolution of the irreversible thermal transitions. Arrhenius equation parameter for the two-state irreversible model of the thermal denaturation of oxy-CCH at pH 7.2 was estimated. Both factors, oligomerization and the copper-dioxygen system at the active site, are important for stabilizing the structure of the hemocyanin molecule.