ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Shanshan Wu,Qiumin Ye,Datong Wu,Yongxin Tao,Yong Kong
Glycine (Gly), an achiral amino acid, has never been reported for enantioselective recognition owing to the absence of chiral sites. Herein, a facile strategy of chirality transfer is proposed to endow Gly with chirality. Optically active CuO, L-CuO, is first prepared, which can be used for the decoration of Gly through the formation of the Cu(Gly)2 complex. Successful chirality transfer from L-CuO to Gly is confirmed by circular dichroism (CD) spectra. The formation of the Cu(Gly)2 complex is further confirmed by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. Next, the resultant L-CuO-Gly is used for chiral analysis of the isomers of tryptophan (Trp). Because of the higher affinity of L-CuO-Gly toward L-Trp than its isomer, the Trp isomers exhibit significant differences in their oxidation peak currents at the L-CuO-Gly-modified glassy carbon electrode (GCE) (IL-Trp/ID-Trp = 5.24). Finally, the practicability of the developed L-CuO-Gly/GCE is assessed, and the results indicate that it could be a reliable chiral sensor for the quantitative analysis of Trp isomers in nonracemic mixtures.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Yanqing Wang,Qianqian Han,Ying Wang,Dan Qin,Qiang Luo,Hongmei Zhang
In this study, aromatic amino acid-conjugated chitosan are designed and developed, as viewed by multi-spectral methods. The results from 1H NMR , FTIR, and UV–vis indicated the successful grafting of tryptophan (Trp) or phenylalanine (Phe) onto chitosan (CS) to form Trp-CS and Phe-CS nano-conjugates with 4.7 % and 6.8 % grafting ratio. The grafting induced some influences on the chiral structure and the symmetry and backbone structure of CS. The thermal stability of Trp-CS and Phe-CS nano-conjugates is less than that of CS. Trp-CS and Phe-CS conjugates were formed as spherical nanoparticles . The rheological studies show that Trp-CS and Phe-CS exhibit characteristic of an elastic material. In addition, Trp-CS and Phe-CS present well antioxidant activities and good biocompatibility.
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ANALYTICA CHIMICA ACTA
·
2014
·
IF 4.517
Qianwen Lian,Zhifang He,Qian He,Ai Luo,Kaiwang Yan,Dongxia Zhang,Xiaoquan Lu,Xibin Zhou
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.
研究领域:
分析化学
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生物医学工程
·
材料科学
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AMINO ACIDS
·
2014
·Vol. 46
·期 12
·2681-2691
·
IF 3.653
Ruan Zheng,Yang Yuhui,Wen Yanmei,Zhou Yan,Fu Xiaofang,Ding Sheng,Liu Gang,Yao Kang,Wu Xin,Deng Zeyuan,Wu Guoyao,Yin Yulong
Tryptophan (TRP) is an important precursor for several neurotransmitters and metabolic regulators, which play a vital role in regulating nutrient metabolism. The purpose of this study was to investigate the effects of tryptophan supplementation on the biochemical profiles, intestinal structure, liver structure and serum metabolome in rats. Rats received daily intragastric administration of either tryptophan at doses of 200 mg/kg body weight per day or saline (control group) for 7 days. TRP supplementation had a tendency to decrease the body weight of rats ( P > 0.05). The levels of urea and CHO in serum were decreased in the TRP-supplemented group rats compared with control group rats ( P < 0.05). TRP supplementation increased the villus height and the ratio of villus height to crypt depth in the jejunum compared to control group rats ( P < 0.05). Metabolic effects of tryptophan supplementation include: (1) increases in the serum concentrations of lysine, glycine, alanine, glutamate, glutamine, citrulline, methionine, tyrosine, 1-methylhistidine, and albumin, and decreases in the concentrations of serum branched-chain amino acid (isoleucine, valine and leucine); (2) decreases in the serum concentrations of formate and nitrogenous products (trimethylamine, TMAO, methylamine and dimethylamine), and in the contraction of trimethylamine in feces; (3) decreases in serum levels of lipids, low density lipoprotein, very low density lipoprotein, together with the elevated ratio of acetoacetate to β-hydroxybutyrate. The results indicate that tryptophan supplementation reduced the catabolism of dietary amino acids and promoted protein synthesis in rats, promoted the oxidation of fatty acid and reduced fat deposition in the body of rats.
研究领域:
营养学
·
代谢组学
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胃肠病学
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生物化学
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SENSORS
·
2016
·Vol. 16
·期 11
·1874
·
IF 2.033
Qi Xiao,Shuangyan Lu,Chusheng Huang,Wei Su,Shan Huang
Based on N-doped carbon dots/β-cyclodextrin nanocomposites modified glassy carbon electrodes (N-CDs/β-CD/GCE), an effective electrochemical sensor for enantioselective recognition of tryptophan (Trp) enantiomers was developed by differential pulse voltammograms (DPVs). Fluorescent N-CDs were synthesized through a hydrothermal method and characterized by spectroscopic approaches. The N-CDs/β-CD nanocomposites were efficiently electrodeposited on the surface of GCE through C–N bond formation between N-CDs and electrode. The obtained N-CDs/β-CD/GCE was characterized by multispectroscopic and electrochemical methods. Such N-CDs/β-CD/GCE generated a significantly lower Ip and more negative Ep in the presence ofl-Trp in DPVs, which was used for the enantioselective recognition of Trp enantiomers. The N-CDs/β-CD nanocomposites showed different binding constants for tryptophan enantiomers, and they further selectively bonded withl-Trp to form inclusion complexes. This N-CDs/β-CD/GCE combined advantages of N-CDs with strong C–N binding ability and β-CD with specific recognition of Trp enantiomers to fabricate a novel sensing platform for enantioselective recognition of Trp enantiomers. This strategy provided the possibility of using a nanostructured sensor to discriminate the chiral molecules in bio-electroanalytical applications.Keywords:N-doped carbon dots;β-cyclodextrin;tryptophan enantiomers;enantioselective recognition;differential pulse voltammetry
研究领域:
分析化学
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生物医学工程
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电化学传感器
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TRANSACTIONS OF TIANJIN UNIVERSITY
·
2017
·Vol. 24
·期 1
·16-24
·
IF 0
Sun Jinsheng,Wei Dongmei,Lv Hao
This study focuses on shape-controlled synthesis of gold nanoparticles, using the green reducing agent l -Tryptophan ( l -Trp), which is non-toxic and eco-friendly. This specific agent was investigated to realize certain morphology controlling effects by changing the relative growth rates among various crystal planes. Experimental samples were characterized by transmission electron microscope, UV–Vis spectrophotometer and X-ray diffraction (XRD) for size and morphological information. The effects of the specific additives of PVP ((C 6 H 9 NO)
n
), CTAB (C 16 H 33 (CH 3 ) 3 NBr), and KBr were examined for their morphological control individually and synergistically in this system. Hexagonal gold nanoparticles were successfully obtained via the PVP/CTAB and PVP/KBr systems. Particular amounts of PVP/KBr produced various polyhedron structures, such as cubes, and others with triangular and rhombic straight-side cross sections.
研究领域:
材料科学
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纳米生物学
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环境科学
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Frontiers in Microbiology
·
2023
·
IF 5.2
Shikai Zhang,Qing Xu,Changbo Ji,Xiaoyu Han,Yang Zhou,Chao Liang,Linran Ma,Weijian Sun,Yanling Li,Zhengyou Yang,Fengchun Zhao,Yuan Tian
Small molecule-induced fermentation of the endophytic fungus Diaporthe sp. AC1 originated from Artemisia argyi was executed to investigate its secondary metabolites. It was fermented in a culture medium containing 5-hydroxytryptophan (5-HTP), 1-methyl-L-tryptophan (1-MT), and tryptamine (TA), respectively. The antibacterial activities of crude extracts against pathogenic bacteria and pathogenic fungi were determined by using the Oxford cup method, while the cytotoxicity of crude extracts against cancer cells was determined by using the MTT method. The results showed that the secondary metabolites of Diaporthe sp. AC1 induced by 1-MT exhibited optimal antibacterial activity and tumor cytotoxicity. The induction conditions of 1-MT were optimized, and the antibacterial activities and tumor cytotoxicity of crude extracts under different induction conditions were investigated. As indicated, the optimal moment for 1-MT addition was before inoculation and its optimal concentration was 0.25 mM. Under these conditions, Diaporthe sp. AC1 was fermented and approximately 12 g of crude extracts was obtained. The crude extracts were then separated and purified to acquire nine monomer compounds, including three new compounds ( 1 – 3 ) and six known compounds ( 4 – 9 ). The antibacterial activities of the compounds against pathogenic bacteria and pathogenic fungi were investigated by using the microdilution method, while their cytotoxicity against cancer cells was analyzed by using the MTT method. The results demonstrated that Compound 1 exhibited moderate antibacterial activities against Verticillium dahlia , Fusarium graminearum, and Botrytis cinerea , as well as a low inhibitory activity against Listeria monocytogenes . Nevertheless, Compound 1 showed significant cytotoxicity against five cancer cells, with IC 50 ranging from 12.26 to 52.52 μM. Compounds 2 and 3 exhibited negligible biological activity, while other compounds showed detectable inhibitory activities against pathogenic bacteria and cancer cells.
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JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Rui Wang,Jie Huang,Yubing Dong,Qiao Xu,Xiuyan Deng,Wenbin Jiang,Yaqin Fu
Electron transfer between tryptophan (Trp) and tyrosine (Tyr) is often accompanied with transient emission of visible blue-purple light, which is very common in numerous laser-induced photolysis experiments. However, recent experiments have shown that in the absence of pulse radiolysis, by mixing Trp and Tyr in concentrated aqueous hydrochloric acid can also produce a blue–purple color as it was observed in photolysis experiments. Unexpectedly, this color is quite stable in strong acid media (it can be kept at room temperature for at least a week). It is proposed that after initial formation of Trp radical products (TrpH ▪+ /Trp ▪ ) by the solvent radical oxidation, charge-transfer complexes were generated via electron transfer reactions between Trp radical products and phenol of Tyr or their directly hole-trapping mechanism, which exhibit a blue-purple color. In this work, HPLC analysis and density functional calculations show that there are loosely reversible associations in the charge-transfer complexes which can be stabilized by strong hydrogen bonding. A Trp radicals signal was observed but the intensity was not so strong as expected. This color reaction exhibits high selectivity towards Trp and Tyr, and thus it can be a convenient method for naked-eye identifying the coexistence of these two amino acids or protein modifications of related to them.
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Frontiers in Immunology
·
2022
·
IF 8.786
Hao Cheng,Juan Liu,Dandan Zhang,Jing Wang,Yuzhu Tan,Wuwen Feng,Cheng Peng
Ulcerative colitis (UC) is a chronic and recurrent inflammatory disorder in the gastrointestinal tract. Here, we examined the pharmacological effects of ginsenoside Rg1, a natural compound with low bioavailability, on the acute experimental colitis mice induced by dextran sulfate sodium (DSS) and explored underlying mechanisms. Acute UC was induced in C57BL/6 mice by 2.5% DSS for 7 days, meanwhile, 2 mg/10 g b.w. ginsenoside Rg1 was administrated to treat the mice. Body weight, colon length, colon tissue pathology, and colon tissue inflammatory cytokines were assessed. The composition structure of gut microbiota was profiled using 16s rRNA sequencing. Global metabolomic profiling of the feces was performed, and tryptophan and its metabolites in the serum were detected. The results showed that Rg1 significantly ameliorated DSS-induced colonic injury and colonic inflammation. In addition, Rg1 also partly reversed the imbalance of gut microbiota composition caused by DSS. Rg1 intervention can regulate various metabolic pathways of gut microbiota such as valine, leucine, and isoleucine biosynthesis and vitamin B6 metabolism and the most prominent metabolic alteration was tryptophan metabolism. DSS decreased the levels of tryptophan metabolites in the serum, including indole-3-carboxaldehyde, indole-3-lactic acid, 3-indolepropionic acid, and niacinamide and Rg1 can increase the levels of these metabolites. In conclusion, the study discovered that Rg1 can protect the intestinal barrier and alleviate colon inflammation in UC mice, and the underlying mechanism is closely related to the regulation of gut microbiota composition and microbial tryptophan metabolism.Keywords: ginsenoside Rg1, gut microbiota, tryptophan, metabolomics, ulcerative colitis
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ANALYTICAL CHEMISTRY
·
2023
·
IF 7.4
Pengjing Jing,Tai Wen,Junyao Li,Wenrong Cai,Baozhu Yang,Yong Kong
Reliable chiral discrimination of enantiomers with simple devices is of great importance for chiral analysis. Here, a chiral sensing platform is developed for chiral discrimination through two different modes: electrochemistry and temperature. Au nanoparticles (AuNPs) are grown in situ on the nanosheets of MXene by utilizing the strong metal reduction ability of MXene, which can be further used for the anchoring of N-acetyl-l-cysteine (NALC), a commonly used chiral source, through Au–S bonds. Owing to the excellent electrical conductivity and photothermal conversion efficiency of MXene, the resultant MXene-AuNPs-NALC is applied in the construction of a chiral sensing platform for the discrimination of tryptophan (Trp) enantiomers through two different modes: electrochemistry and temperature. Compared with conventional single-mode chiral sensors, the proposed chiral sensing platform can integrate two different indicators (currents and temperature) into one chiral sensor, greatly improving the reliability of chiral discrimination.
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Biomolecules
·
2019
·Vol. 9
·期 7
·294
·
IF 4.694
Yaling Tian,Peihong Deng,Yiyong Wu,Ziyu Ding,Guangli Li,Jun Liu,Quanguo He
In this paper, a tryptophan (Trp) molecularly imprinted chitosan film was prepared on the surface of an acetylene black paste electrode using chitosan as the functional polymer, Trp as the template molecule and sulfuric acid as the crosslinking agent. The surface morphologies of non-imprinted and imprinted electrodes were characterized by scanning electron microscopy (SEM). The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy. Some factors affecting the performance of the imprinted electrode such as the concentration of chitosan, the mass ratio of chitosan to Trp, the dropping amount of the chitosan-Trp mixture, the solution pH, and the accumulation potential and time were discussed. The experimental results show that the imprinted electrode exhibit good affinity and selectivity for Trp. The dynamic linear ranges of 0.01–4 μM, 4–20 μM and 20–100 μM were obtained by second derivative linear sweep voltammetry, and the detection limit was calculated to be 8.0 nM. The use of the imprinted electrode provides an effective method for eliminating the interference of potentially interfering substances. In addition, the sensor has high sensitivity, reproducibility and stability, and can be used for the determination of Trp in pharmaceutical preparations and human serum samples.Keywords:molecularly imprinted chitosan film;electrochemical sensor;tryptophan;selective determination
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Food Frontiers
·
2024
·
IF 7.4
Hang Yu,Jingmin Fan,Rui Xue,Jiawei Guan,Fangyuan Tian,Yu Xu,Linyun He,Ji Liu,Zhenzhu Du,Daqun Chen,Wei Yu,Wen Chen,Bo Han
Alhagi honey (AH) is produced in arid and hot areas of Central Asia, and its polysaccharides (AP) are widely known for their activity in the treatment of intestinal diseases such as diarrhea. However, the therapeutic potential and mechanism of AP in ulcerative colitis (UC) remain unclear. Here, AH polysaccharide-2 (AP2), a polysaccharide with the highest content in AP, was isolated and evaluated for its effects on dextran sulfate sodium (DSS)-induced UC in mice. AP2 was found to alleviate UC symptoms and regulate gut microbiota dysbiosis by decreasing Helicobacter levels and increasing Lactobacillus levels. Analysis of PICRUSt2 predicted that AP2 may regulate carbohydrate and amino acid metabolism, and metabolomic analysis confirmed that AP2 promotes the metabolism of tryptophan to produce kynurenic acid (kyna). Moreover, kyna acted as an aryl hydrocarbon receptor (AhR) ligand, which activated AhR to increase the expression of the tight junction proteins claudin-1 and occludin. Interestingly, AP2 showed similar effects in protecting the intestinal barrier and alleviating colitis as the AhR agonist 6-formylindolo[3,2- b ]carbazole, and the AhR antagonist CH223191 partially blocked the therapeutic effect of AP2 in UC mice, indicating that the anti-UC effect of AP2 was AhR dependent. These findings demonstrate that AP2 alleviates UC by regulating the gut microbiota and promoting tryptophan metabolism to generate kyna-activated AhR. The insights gained from this study could help in the future development of AP2 as a drug candidate or functional food for the treatment of UC.
研究领域:
胃肠病学
·
免疫学
·
微生物学
·
药理学
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