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1.
TX-114+TBAB体系中非电解质对CP的影响 总被引:1,自引:1,他引:0
The effects of nonelectrolytes (ureas, amino acids, sugars) on the cloud point (CP) of nonionic surfactant Triton X-114 (TX-114) and tetra-n-butylammonium bromide (TBAB) system were studied. Ureas as well as thioureas increased the CP. Behaviors of amino acids depended upon their nature. Nonpolar and uncharged polar amino acids were less effective in changing the CP. However, tryptophan and phenylalanine increased the CP sharply. Acidic amino acid (aspartic acid) and sugars decreased the CP. The results were explained in terms of their effect on water structure. Amino acids got solubilized either in the micellar interior or in the bulk phase. 相似文献
2.
The effects of nonelectrolytes(ureas,amino acids,sugars)on the cloud point(CP)of nonionic surfactantTriton X-114(TX-114)and tetra-n-butylammonium bromide(TBAB)system were studied.Ureas as well as thioureasincreased the CP.Behaviors of amino acids depended upon their nature.Nonpolar and uncharged polar anlino acidswere less effective in changing the CP.However,tryptophan and phenylalanine increased the CP sharply.Acidicamino acid(aspartic acid)and sugars decreased the CP.The results were explained in terms of their effect on waterstructure.Amino acids got solubilized either in the micellar interior or in the bulk phase. 相似文献
3.
Herein we report the effect of various additives (viz. alcohols, cycloalcohols, amino acids, sugars, ureas) on the clouding phenomenon observed in 50mM chlorpromazine hydrochloride (CPZ) drug solutions (prepared in 10mM sodium phosphate buffer). Long chain alcohols (except octanol), cyclohexanol and allylalcohol increased the cloud point (CP) followed by a decrease with the increase in alcohol concentration but short chain alcohols affected the CP insignificantly. Effect of amino acids depended upon their nature: acidic and salts of basic amino acids increased the CP while basic amino acids depressed it; non-polar and uncharged polar amino acids caused small changes in CP. Additives of urea family decreased the CP. All sugars caused a decrease in CP, which is in consonance to their effect on the critical micellar concentration. The overall behavior is explained on the basis of additives affecting the solvent as well as micelle aggregation and/or structure. 相似文献
4.
Córdova A Ibrahem I Casas J Sundén H Engqvist M Reyes E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(16):4772-4784
Hexose sugars play a fundamental role in vital biochemical processes and their biosynthesis is achieved through enzyme-catalyzed pathways. Herein we disclose the ability of amino acids to catalyze the asymmetric neogenesis of carbohydrates by sequential cross-aldol reactions. The amino acids mediate the asymmetric de novo synthesis of natural L- and D-hexoses and their analogues with excellent stereoselectivity in organic solvents. In some cases, the four new stereocenters are assembled with almost absolute stereocontrol. The unique feature of these results is that, when an amino acid is employed as the catalyst, a single reaction sequence can convert a protected glycol aldehyde into a hexose in one step. For example, proline and its derivatives catalyze the asymmetric neogenesis of allose with >99 % ee in one chemical manipulation. Furthermore, all amino acids tested catalyzed the asymmetric formation of natural sugars under prebiotic conditions, with alanine being the smallest catalyst. The inherent simplicity of this catalytic process suggests that a catalytic prebiotic "gluconeogenesis" may occur, in which amino acids transfer their stereochemical information to sugars. In addition, the amino acid catalyzed stereoselective sequential cross-aldol reactions were performed as a two-step procedure with different aldehydes as acceptors and nucleophiles. The employment of two different amino acids as catalysts for the iterative direct aldol reactions enabled the asymmetric synthesis of deoxysugars with >99 % ee. In addition, the direct amino acid catalyzed C(2)+C(2)+C(2) methodology is a new entry for the short, highly enantioselective de novo synthesis of carbohydrate derivatives, isotope-labeled sugars, and polyketide natural products. The one-pot asymmetric de novo syntheses of deoxy and polyketide carbohydrates involved a novel dynamic kinetic asymmetric transformation (DYKAT) mediated by an amino acid. 相似文献
5.
This paper reports the influence of organic additives (alcohols, amino acids, sugars) on the micellization and cloud point
(CP) of a phenothiazine drug, promethazine hydrochloride (PMT). The critical micelle concentration (CMC) of the drug, determined
by surface tension measurements in the presence of a representative of each additive class (i.e., butanol, leucine, arabinose),
are used to evaluate the maximum surface excess concentration (Γ
max) and the minimum area per surfactant molecule (A
min) at the air/water interface. Γ
max increases and CMC/A
min decreases with increasing concentration of the additives, which indicate mixed micelle formation. The intermicellar interaction
coefficients in the mixed micelles (β
m and β
σ are also calculated, and their negative values imply attractive interactions. Effect of pH revealed CP decrease with increasing
pH due to deprotonation of PMT molecules. Effect of amino acids depended upon their nature and polarity, whereas sugars caused
a CP decreasing effect. Aliphatic alcohols as well as cycloalkanols and diols decreased the CP. In the presence of arabinose,
increase in drug concentration resulted in the CP increase, while increase in pH showed an opposite trend. Results are interpreted
on the basis of mixed micelle formation, hydrophobic interactions, and change in solvent structure. 相似文献
6.
Meng-Fei Guo Huan-Huan Zhang Ping Zhong Jin-Di Xu Shan-Shan Zhou Fang Long Ming Kong Qian Mao Song-Lin Li 《Molecules (Basel, Switzerland)》2022,27(22)
Cicadae Periostracum (CP) is a traditional Chinese medicinal herb derived from the slough that is molted from the nymph of the insect Cryptotympana pustulata Fabricius. Washing with water to remove residual silt is a primary processing method of CP that is recommended by the Chinese Pharmacopoeia, but how washing methods affect the quality and bioactivity of CP is unknown. In this study, the quality and bioactivity of non-washed CP (CP-NW), post-molting-washed CP (CP-WAT), and pre-molting-washed CP (CP-WBT) were comparatively investigated. The quality of these CP samples was evaluated in terms of the UPLC-QTOF-MS/MS-based chemical profiling and semi-quantification of 39 N-acetyldopamine oligomers (belonging to six chemical types), the HPLC-UV-based quantification of 17 amino acids, the ICP-MS-based quantification of four heavy metals, and the contents of ash; the bioactivities of the samples were compared regarding their anti-oxidant and anti-inflammatory activities. It was found that, compared with CP-NW, both CP-WBT and CP-WAT had significantly lower contents of ash and heavy metals. Moreover, compared with CP-WAT, CP-WBT contained lower levels of total ash, acid-insoluble ash, and heavy metals and higher contents of N-acetyldopamine oligomers and amino acids. It also had enhanced anti-oxidant and anti-inflammatory activities. A Spearman’s correlation analysis found that the contents of N-acetyldopamine oligomers and free amino acids were positively correlated with the anti-oxidant/-inflammatory activities of CP. All these results suggest that pre-molting washing can not only remove the residual silt but can also avoid the loss of the bioactive components and assure higher bioactivities. It is concluded that pre-molting washing could enhance the quality and bioactivity of CP and should be a superior alternative method for the primary processing of qualified CP. 相似文献
7.
An automated procedure, with o-phthaldialdehyde as a fluorogenic reagent for the determination of total α-amino acids in natural waters is given. The response of different amino acids, dipeptides and amino sugars has been tested as well as the interference of other nitrogen-containing substances. The method is well suited to determinations of the amino acid content in the range 0.05–15 μM with an analysis rate of 20 samples per hour. 相似文献
8.
Fei Ye Xiaoyan Qiao Anhui Gui Shengpeng Wang Panpan Liu Xueping Wang Jin Teng Lin Zheng Lin Feng Hanshan Han Shiwei Gao Pengcheng Zheng 《Molecules (Basel, Switzerland)》2021,26(21)
This study aimed to compare the effect of hot roller (HR) drying and hot air (HA) drying on the sensory evaluation, chemical quality, antioxidant activity, and metabolic profile of Yihong Congou black tea processed from E’cha NO1. The Yihong Congou black tea dried with HA obtained higher sensory scores and better chemical qualities such as the hue of tea brew color (a and b), content of theaflavins, thearubigins, water extract, free amino acids, tea polyphenol, and the ratio of polyphenol to amino acids as well as higher antioxidant capacities compared to that dried with HR. The HA drying tea increased the contents of volatile compounds that had positive correlation with sweet and flowery flavor, while the HR drying tea increased the contents of volatile compounds related to fruity flavor. Moreover, non-targeted metabolomics data indicated that the levels of most free amino acids significantly increased, while the levels of most soluble sugars reduced in the HA drying method compared to the HR drying method. The metabolic analysis was also consistent with the above results and revealed that D-ribose and gallic acid were the main characteristic metabolites of HA drying. Our results could provide a technical reference and theoretical guide to processing a high quality of Yihong Congou black tea. 相似文献
9.
1. RF values of 12 amino acids were determined in phenol-water and benzyl alcohol-acetic acid-water using unidimensional and circular techniques of paper chromatography. 2. It has been observed that the square of circular RF values (considering frontal boundary of solute) equals the linear RF values, and this relation is valid for the amino acids as well as the sugars studied. 3. The relation is found to be independent of the distance traversed by the solvent in the case of both amino acids and sugars. 4. A theoretical support has been given to the experimental observations. 相似文献
10.
The amino sugars (e.g., glucosamine, galactosamine, mannosamine, muramic acid) in soils are frequently employed as biomarkers of microbial residues. The analysis of amino sugars in environmental matrices, however, is expected to be more complicated than their determination in isolated microbial cells. In this study, we employed a widely used protocol for amino sugar analysis, and found that some aminoglycoside antibiotics interfere with amino sugar quantification in vitro. The method converts the aminoglycosides to compounds that coelute with the aldononitrile acetate derivatives of the amino sugars. Specifically, streptomycin significantly interferes with muramic acid analysis, and kanamycin, tobramycin and amikacin hamper glucosamine measurement. Mass spectrometry confirmed that the interfering compounds from aminoglycosides are not actually genuine microbial amino sugar monomers (bacterial muramic acid or fungal glucosamine), and are most likely to be N-methyl glucosamine or 3-amino-3-deoxy-glucopyranose. In contrast to their effects on muramic acid and glucosamine analyses, aminoglycosides do not interfere with galactosamine and mannosamine quantification. The few data that exist on the environmental occurrence of aminoglycoside antibiotics suggest they occur at only trace levels. Our findings may have implications for the qualitative and quantitative validity of results from amino sugar assays in some context. Application of the aldononitrile acetate derivatization method to samples (especially in selective microbial cultures using aminoglycosides as inhibitors) requires that potential interference be evaluated. 相似文献
11.
Watanabe K Tanaka R Sakurai H Iguchi K Yamada Y Hsu CS Sakuma C Kikuchi H Shibayama H Kawai T 《Chemical & pharmaceutical bulletin》2007,55(5):780-783
The structure of a new monomeric peptidoglycan-related compound with hypotensive and diuretic activities, cymbidine A (1) isolated from the orchid Cymbidium goeringii, was elucidated mainly by spectroscopic analysis. The structure of 1 was shown to involve four amino acids (D-alanin, meso-diaminopimelic acid, D-gultamic acid, and L-valine) and two amino sugars (N-acetylglucosamine and 1,6-anhydro-N-acetylmuramic acid). The sequence of the amino acids and amino sugars was determined by the analysis of 2D NMR data. The absolute stereochemistries of the three amino acids (D-Ala, D-Glu and L-Val) were determined by the modified Marfey's method, and the (6S,10R) configurations of meso-diaminopimelic acid in 1 were indicated on the basis of the CD analysis. The absolute stereochemistry of 1,6-anhydro-N-acetylmuramic acid was also determined by CD data. 相似文献
12.
Baumler DJ Hung KF Bose JL Vykhodets BM Cheng CM Jeong KC Kaspar CW 《Applied biochemistry and biotechnology》2006,134(1):15-26
A portion of the cbpA gene from Escherichia coli K-12 encoding a 24 amino acid proton-buffering peptide (Pbp) was cloned via the shuttle vector pJB99 into E. coli JM105 and subsequently into Zymomonas mobilis CP4. Expression of Pbp was confirmed in both JM105 and CP4 by HPLC. Z. mobilis CP4 carrying pJB99-2 (Pbp) exhibited increased acid tolerance (p<0.05) in acidified TSB (HCl [pH 3.0] or acetic acid [pH 3.5]), glycine-HCl buffer (pH 3.0), and sodium acetate-acetic acid
buffer (pH 3.5) in comparison to the parent strain (CP4) and CP4 with pJB99 (control plasmid). Although the expression of
Pbp influenced survival at a low pH, the minimum growth pH was unaffected. Growth of Z. mobilis in the presence of ampicillin also significantly increased acid tolerance by an unknown mechanism. Results from this study
demonstrate that the production of a peptide with a high proportion of basic amino acids can contribute to protection from
low pH and weak organic acids such as acetic acid. 相似文献
13.
M. Elaloui A. Laamouri J. Fabre C. Mathieu G. Vilarem B. Hasnaoui 《Natural product research》2015,29(1):94-97
Ziziphus jujuba pulps are very much appreciated by the inhabitants and have been recently exported. This article reports on the chemical composition (amino acids, polyphenols and sugars) of the pulps of four Z. jujuba ecotypes (Choutrana, Mahdia, Mahres and Sfax). The major amino acids identified were proline, aspartic acid and glutamic acid. Among these, proline was the most abundant amino acid (17.4 mol). Considerable differences in total phenolic contents (15.85 mg/L) were found. Predominant phenols identified by using HPLC were rutin (1.09 mg/L) and chlorogenic acid (2.57 mg/100 g). Sugars isolated from Ziziphus pulps were found at a rate of 43.52%. Using HPLC method, three sugars from the pulp extract were identified: glucose, galactose and sucrose. The Mahdia ecotype was the richest in these sugars with 0.45, 136.51 and 113.28 mg/L, respectively. 相似文献
14.
Kim S Shin MH Hossain MA Yun EJ Lee H Kim KH 《Analytical and bioanalytical chemistry》2011,399(10):3519-3528
The effect of sugar on plant metabolism, which is known to be similar to hormone-like signaling, was metabolomically studied
using Melissa officinalis (lemon balm). The metabolite profiles of M. officinalis treated with sucrose were analyzed by gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA).
A total of 64 metabolites from various chemical classes including alcohols, amines, amino acids, fatty acids, inorganic acids,
organic acids, phosphates, and sugars were identified by GC-MS. Three groups treated with different sucrose concentrations
were clearly separated by PCA of their metabolite profiles, indicating changes in the levels of many metabolites depending
on the sucrose concentration. Metabolite profiling revealed that treatment with a higher sucrose level caused an increase
in the levels of metabolites such as sugars, sugar alcohols, and sugar phosphates, which are related to the glycolytic pathway
of M. officinalis. Furthermore, proline and succinic acid, which are associated with the proline-linked pentose phosphate pathway, the shikimic
acid pathway, and the biosynthesis of phenylpropanoids, also increased with increasing sucrose concentration. Therefore, these
metabolic changes induced by sucrose ultimately led to the increased production of flavonoids such as caffeic acid via the
biosynthetic pathway of phenylpropanoids. This study demonstrated that the abundance changes in some primary and secondary
metabolites were somewhat interlocked with each other in response to sucrose. 相似文献
15.
Yuchao Feng Xia Fan Shu Zhang Miao Yu Tong Wu Ying Liang Changyuan Wang Hongzhi Yang 《Molecules (Basel, Switzerland)》2022,27(12)
An ultra-high-performance liquid chromatography coupled with high-field quadrupole-orbitrap mass spectrometry (UHPLC-QE-MS) histological platform was used to analyze the effects of two thermal processing methods (cooking and steaming) on the nutritional metabolic components of black beans. Black beans had the most amino acids, followed by lipids and polyphenols, and more sugars. Multivariate statistical analysis indicated that heat processing significantly affected the metabolic component content in black beans, with effects varying among different components. Polyphenols, especially flavonoids and isoflavones, were highly susceptible. A total of 197 and 210 differential metabolites were identified in both raw black beans and cooked and steamed black beans, respectively. Cooking reduced the cumulative content of amino acids, lipids, polyphenols, sugars, and nucleosides, whereas steaming reduced amino acid and lipid content, slightly increased polyphenol content, and significantly increased sugar and nucleoside content. Our results indicated that metabolic components were better retained during steaming than cooking. Heat treatment had the greatest impact on amino acids, followed by polyphenols, fatty acids, sugars, and vitamins, indicating that cooking promotes the transformation of most substances and the synthesis of a few. The results of this study provide a basis for further research and development of nutritional products using black beans. 相似文献
16.
The nature of the carbohydrate-peptide bond and the composition of the carbohydrate chain in a β-1,3-glucanase from the marine molluskS. sachalinensis has been investigated. According to the results of the phenol-sulfuric acid method, the neutral sugars amounted to 6.5% of the molecular weight of the enzyme. The composition of the neutral sugars (Glc : Gal : Man 5:2:1) was determined by the GLC method. It was shown that the β-1,3-glucanase molecule contains no uronic or sialic acids. The amount of amino sugars (15% with equal amounts of glucosamine and galactosamine) was established by amino acid analysis. Alkaline degradation led via the β-elimination reaction to the splitting out of 50% of the neutral sugars and showed the existence of an O-glycosidic bond in the enzyme molecule. Various actions on the carbohydrate moiety (periodate oxidation and treatment with glycosidases) caused no appreciable change in the hydrolyzing capacity of the enzyme. 相似文献
17.
Melissa officinalis contains various secondary metabolites that have health benefits. Generally, irradiating plants with ultraviolet (UV)-B induces the accumulation of secondary metabolites in plants. To understand the effect of UV-B irradiation on the metabolism of M. officinalis, metabolomics based on gas chromatography-mass spectrometry (GC-MS) was used in this study. The GC-MS analysis revealed 37 identified metabolites from various chemical classes, including alcohols, amino acids, inorganic acids, organic acids, and sugars. The metabolite profiles of the groups of M. officinalis irradiated with UV-B were separated and differentiated according to their irradiation times (i.e., 0, 1, and 2 h), using principal component analysis (PCA) and hierarchical clustering analysis (HCA), respectively. The PCA score plots of PC1 and PC2 showed that the three groups with different irradiation times followed a certain trajectory with increasing UV-B irradiation. HCA revealed that metabolic patterns differed among the three groups, and the 1 h-irradiated group was more similar to the control group (0 h) than the 2 h-irradiated group. In particular, UV-B irradiation of plants led to a decrease in sugars such as fructose, galactose, sucrose, and trehalose and an increase in metabolites in the tricarboxylic acid cycle, the proline-linked pentose phosphate pathway, and the phenylpropanoid pathway. This study demonstrated that metabolite profiling with GC-MS is useful for gaining a holistic understanding of UV-induced changes in plant metabolism. 相似文献
18.
Poncirin (PC) and its aglycone, isosakuranetin (IR), occur naturally in citrus fruits. This study aimed to explore the pathways behind the different health benefits of PC and IR by evaluating the effect of these two bioactive flavonoids on the gut microbial diversity and metabolomics of mice. The 16S rRNA gene sequencing was used to analyze the alteration of gut microbiota in mice after PC and IR intervention. The metabolic impact of PC and IR in mice were studied using a metabolomics approach based on LC-MS analysis. Results showed that, after 7 days intervention, PC and IR multiplied the abundance of Parabacteroides in mice’s intestinal tracts by 1.2 and 1.0 times, respectively. PC increased the abundance of Bacteroides by 2.4 times. IR reduced the Allobaculum abundance by 1.0 time and increased Alloprevotella abundance by 1.5 times. When mice were given PC, their fecal acetic acid level increased by 1.8 times, while their isobutyric and isovaleric acid content increased by 1.2 and 1.3 times, respectively. Supplementation with IR had no significant effect on the content of short-chain fatty acids (SCFAs) in the feces of mice. The potential urine biomarkers of mice in the PC group were involved in the digestion and absorption of protein and carbohydrate, as well as the metabolism of amino acids, such as glycine, serine, threonine, tryptophan, D-arginine, D-ornithine, etc. IR mainly affected the amino acid metabolic pathways in mice, including taurine and hypotaurine metabolism, glutathione metabolism, histidine metabolism, D-glutamate metabolism, etc. This study provided valuable clues for future research on the health promoting mechanisms of PC and IR. 相似文献
19.
Xueyan Lu Yan Jin Xiaorui Guo Mingyuan Xu Zhonghua Tang Qi Chen 《Molecules (Basel, Switzerland)》2022,27(24)
Coexisting salt and alkaline stresses seriously threaten plant survival. Most studies have focused on halophytes; however, knowledge on how plants defend against saline–alkali stress is limited. This study investigated the role of Taraxacum mongolicum in a Puccinellia tenuiflora community under environmental saline–alkali stress to analyse the response of elements and metabolites in T. mongolicum, using P. tenuiflora as a control. The results show that the macroelements Ca and Mg are significantly accumulated in the aboveground parts (particularly in the stem) of T. mongolicum. Microelements B and Mo are also accumulated in T. mongolicum. Microelement B can adjust the transformation of sugars, and Mo contributes to the improvement in nitrogen metabolism. Furthermore, the metabolomic results demonstrate that T. mongolicum leads to decreased sugar accumulation and increased amounts of amino acids and organic acids to help plants resist saline–alkali stress. The resource allocation of carbon (sugar) and nitrogen (amino acids) results in the accumulation of only a few phenolic metabolites (i.e., petunidin, chlorogenic acid, and quercetin-3-O-rhamnoside) in T. mongolicum. These phenolic metabolites help to scavenge excess reactive oxygen species. Our study primarily helps in understanding the contribution of T. mongolicum in P. tenuiflora communities on coping with saline–alkali stress. 相似文献
20.
Durgesh Nandni Kulwinder Kumar Vohra Rakesh Kumar Mahajan 《Journal of solution chemistry》2012,41(4):702-714
Surfactant?Cbiomolecule interactions have been investigated by studying the additive effect of various kinds of biomolecules such as amino acids, dipeptides, amino alcohols, sugars, hydroxy acids and dicarboxylic acids on the cloud point behavior of nonionic surfactants including triblock polymers (L64, P84) and tritons (TX100, TX114). In most cases, addition of biomolecules has been found to cause a depression in the cloud point of the triblock polymers and tritons. The presence of biomolecules in the solution of a nonionic surfactant causes drastic changes to the clouding behavior of the surfactant, especially at high biomolecule concentrations. The results reveal that both hydrophobicity and structural aspects play important roles in the observed cloud point variation of the nonionic surfactants. 相似文献