l-tryptophan

The radiosynthesis and GMP validation of [11 C] AMT for human use is described. Three consecutive batches were produced giving 940-3790 MBq (4-17% RCY, decay corrected, based on [11 C]CO2 ). The molar activity at the end of synthesis was 19-35 GBq/μmol, the radiochemical purity was ≥98% and the enantiomeric purity was >99%. While the synthesis method was automated using a new generation of synthesis equipment, Tracer Production System (TPS) developed in house, the method should be readily applicable to other synthesis platforms with minor modifications...

Genetic improvement for stress tolerance requires a solid understanding of biochemical processes involved with different physiological mechanisms and their relationships with different traits. The objective of this study was to demonstrate genetic variability in altered metabolic levels in a panel of six wheat genotypes in contrasting temperature regimes, and to quantify the correlation between those metabolites with different traits. In a controlled environment experiment, heat stress (35:28 ± 0.08°C) was initiated 10 days after anthesis...

The determination of neurotransmitters (NTs) as relevant potential biomarkers in the study of various central nervous system (CNS) pathologies has been demonstrated. Knowing that NTs-related diseases mostly occupy individual regions of the nervous system, as observed, for instance, in neurodegenerative diseases (Alzheimer’s and Parkinson’s Diseases), the analysis of brain slices is preferred to whole-brain analysis. In this report, we present sample preparation approaches, such as solid-phase extraction, solid-phase microextraction, and dispersive liquid⁻liquid microextraction, and discuss the pitfalls and advantages of each extraction method...

Since a racemic mixture of chiral nucleotides frustrates the enzymeless extension of RNA and DNA, the origin of homochirality must be intimately connected with the origin of life. Homochirality theories have elected to presume abiotic mechanisms for prebiotic enantiomer enrichment and post amplification, but none, so far, has been generally accepted. Here I present a novel hypothesis for the procurement of homochirality from an asymmetry in right- over left-circularly polarized photon-induced denaturing of RNA and DNA at the Archean ocean surface as temperatures descended below that of RNA and DNA melting...

Aptamers are chemically synthesized oligonucleotides or peptides with molecular recognition capabilities. We investigated recognition of substrate-tethered small-molecule targets, using neurotransmitters as examples, and fluorescently labeled DNA aptamers. Substrate regions patterned via microfluidic channels with dopamine or L-tryptophan were selectively recognized by previously identified dopamine or L-tryptophan aptamers, respectively. The on-substrate dissociation constant determined for the dopamine aptamer was comparable to, though slightly greater than the previously determined solution dissociation constant...

Kudiezi injection (KDZI), also known as Diemailing injection, is a traditional Chinese medicine injection of the composite plant Ixeris sonchifolia Hance (also known as Kudiezi), and has been widely used to treat coronary heart disease, angina pectoris, and cerebral infarction, but its pharmacological mechanisms remain unclear. This study is designed to explore the effects of KDZI on middle cerebral artery occlusion and reperfusion (MCAO/R) rats, and to identify metabolic features of cerebral ischemia reperfusion by using a nontargeted metabolic profiling method based on ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS)...

At present environmental scenario global climate change is a reality and its affect all living organism including fish. The aquatic ecosystem is the most affected system as it is the biggest sink for global warming and elevated temperature and obviously affects all the aquatic life forms. With this hypothesis an experiment was conducted to evaluate the effect of elevated temperature on Labeo rohita fingerlings and potential of dietary L-tryptophan (TRP) in mitigating the effects elevated temperature and enhancing the non-specific immunity...

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane...

The aim was to isolate, characterize, and explore potentials of gut bacteria from the earthworm (Metaphire posthuma) and imply these bacteria for remediation of Cu(II) and Zn(II). An extracellular polymeric substance (EPS) producing gut bacteria (Bacillus licheniformis strain KX657843) was isolated and identified based on 16S rRNA sequencing and phylogenetic analysis. The strain showed maximum tolerance of 8 and 6 mM for Cu(II) and Zn(II) respectively. It removed 34.5% of Cu(II) and 54.4% of Zn(II) at 25 mg L-1 after 72 and 96 h incubation respectively...

Nowadays, ionic liquids (ILs) are receiving more attention in various fields of analytical chemistry. Their contribution to the enhancement of the clean-up, extraction, separation and determination of trace amounts of various biologically important compounds in distinct matrices is well documented. Moreover, their importance as "green chemistry" solvents has been pointed out. Advanced analytical methods based on the IL-assisted microextraction and electrophoretic determination of minute concentrations of neurotransmitters (NTs) in samples are presented here for the first time...

In rodents and humans, aromatic amino acids increase gut hormone secretion and H+ -K+ -ATPase activity by modulating calcium-sensing receptor (CaSR). However, the role of CaSR and its related signaling molecules in amino acid-induced gut hormone secretion in swine has not been investigated. Here, we examined whether a CaSR-dependent pathway modulated gastrin and somatostatin (SS) secretion and H+ -K+ -ATPase activity in pigs. Perfusion of pig stomach tissues in the presence of extracellular 80 mM l-phenylalanine (Phe) or 20 mM l-tryptophan (Trp) and a CaSR agonist cinacalcet triggered gastrin and SS secretion and H+ -K+ -ATPase activity (P < 0...

One new indolocarbazole, 3-hydroxy-K252d ( 3 ), together with the recently reported 3-hydroxyholyrine A ( 1 ) and 3'- N -acetyl-3-hydroxyholyrine A ( 2 ), were obtained by feeding a culture of the marine-derived Streptomyces strain OUCMDZ-3118 with 5-hydroxy-l-tryptophan. Their structures were elucidated on the basis of spectroscopic analysis. Compound 1 potently induced apoptosis of gastric cancer cells by inhibiting topoisomerase IIα enzyme activity and reducing the expression of antiapoptosis protein level...

The realization of surface-enhanced Raman spectroscopy (SERS) to be a reliable quantitative analytical technique requires sensitive and reproducible enhancing substrates. Here, uniform three-dimensional (3D) Ag nanorod (AgNR) substrates with well-defined interlayer spacings are prepared through the air-liquid interface-assisted self-assembly of AgNR in a layer-by-layer manner. The correlation of the SERS performance with the 3D AgNR structures is performed by SERS mapping the substrates. SERS mapping reveals the excellent enhancement uniformity of the 3D substrates with the relative standard deviation (RSD) less than 10%...

We previously reported that cisplatin potentiated ileal 5-hydroxytryptamine (5-HT) metabolism and caused pathological changes with an inflammatory response in the delayed phase (72 h) after administration to rats. In the present study, we further investigated the time-dependent effect of cisplatin on ileal 5-HT metabolism and the effects of combining cisplatin and anti-inflammatory drugs on ileal tryptophan hydroxylase expression and pica (the consumption of non-nutritive materials such as kaolin). Cyclooxygenase-2 (COX-2) expression was significantly increased at 24 h after cisplatin (5 mg/kg, intraperitoneal) administration...

The analogous β-carboline alkaloids, harmaline (HAL) and harmine (HAR), possess a variety of biological properties, including acetylcholinesterase (AChE) inhibitory activity, antioxidant, anti-inflammatory, and many others, and have great potential for treating Alzheimer's disease (AD). However, studies have showed that the two compounds have similar structures and in vitro AChE inhibitory activities but with significant difference in bioavailability. The objective of this study was to comparatively investigate the effects of HAL and HAR in memory deficits of scopolamine-induced mice...

l-tryptophan (l-Trp), an essential amino acid, is well known as a precursor of 5-hydroxytryptamine (5-HT) and melatonin. In mammals, l-Trp itself has been reported to suppress gastric emptying in mammals. In addition, 5-HT and melatonin are found in the gastrointestinal tract and affect food passage from the digestive tract in mammals. While the function of these factors in mammals is documented, there is little knowledge on their function in the digestive tract of birds. Therefore, the purpose of the present study was to determine if l-Trp and its metabolites affect the crop emptying rate in chicks (Gallus gallus)...

Herein are reported findings in vitro suggesting both functional and regulatory cross-talk between the human 2-oxoglutarate dehydrogenase complex (hOGDHc), a key regulatory enzyme within the tricarboxylic acid cycle (TCA cycle), and a novel 2-oxoadipate dehydrogenase complex (hOADHc) from the final degradation pathway of l-lysine, l-hydroxylysine and l-tryptophan. The following could be concluded from our studies by using hOGDHc and hOADHc assembled from their individually expressed components in vitro: (i) Different substrate preferences (kcat /Km ) were displayed by the two complexes even though they share the same dihydrolipoyl succinyltransferase (hE2o) and dihydrolipoyl dehydrogenase (hE3) components; (ii) Different binding modes were in evidence for the binary hE1o-hE2o and hE1a-hE2o subcomplexes according to fluorescence titrations using site-specifically labeled hE2o-derived proteins; (iii) Similarly to hE1o, the hE1a also forms the ThDP-enamine radical from 2-oxoadipate (electron paramagnetic resonance detection) in the oxidative half reaction; (iv) Both complexes produced superoxide/H2 O2 from O2 in the reductive half reaction suggesting that hE1o, and hE1a (within their complexes) could both be sources of reactive oxygen species generation in mitochondria from 2-oxoglutarate and 2-oxoadipate, respectively; (v) Based on our findings, we speculate that hE2o can serve as a trans-glutarylase, in addition to being a trans-succinylase, a role suggested by others; (vi) The glutaryl-CoA produced by hOADHc inhibits hE1o, as does succinyl-CoA, suggesting a regulatory cross-talk between the two complexes on the different metabolic pathways...

OBJECTIVE: Parasomnias are common in childhood but there is no established treatment for parasomnias. The aim of this study was to (1) report on the outcome of using L-tryptophan to manage parasomnias in children and (2) examine sleep architecture and subjective psychological/sleep symptoms in children with parasomnia. METHOD: A retrospective analysis was conducted of charts of children (3-18 years old) who underwent polysomnographic testing and were diagnosed with primary parasomnia...

Background: 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. Objective: 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. Methods: To determine the MA of lysine, 4 amounts of l-lysine (10, 13, 16, and 18 mg ...

The L-tryptophan (Trp) biosynthesis pathway is highly regulated at multiple levels. The three types of regulations identified so far, namely repression, attenuation, and feedback inhibition have greatly impacted our understanding and engineering of cellular metabolism. In this study, feed-forward regulation is discovered as a novel regulation of this pathway and explored for engineering Escherichia coli for more efficient Trp biosynthesis. Specifically, indole glycerol phosphate synthase (IGPS) of the multifunctional enzyme TrpC from E...