应用不同柱前衍生法于HPLC测定西洋参中的氨基酸

通过微波水解衍生方法与柱前衍生方法测定西洋参中的氨基酸成分并进行对比,评价两种方法使用的合理性与应用价值。通过微波水解衍生及柱前衍生两种不同的衍生方法测定同一来源的西洋参药材中的氨基酸成分含量,比较两种实验方法的操作性、准确合理性及测定氨基酸成分含量。两种实验方法平均回收率及相对标准偏差为:柱前衍生法回收率90.1%~101.7%、RSD 0.9%~3.9%,微波水解衍生法90.1%~113.1%、RSD 1.1%~9.5%(除个别氨基酸在酸水解过程中易被破坏)。柱前衍生法主要测定游离氨基酸的含量,其中西洋参根中的精氨酸占总量的59%。微波衍生法明显缩短了氨基酸分析时间,实验操作上体现显著优势。柱前衍生法准确、可靠,测定产物稳定。测定西洋参干燥根中游离的精氨酸含量占游离氨基酸总量的一半以上,含量最高,为西洋参的化学成分与药理作用的进一步研究提供参考依据。     

冬虫夏草口服液游离氨基酸和微量元素的分析比较

目的：为了研究冬虫夏草口服液的有效成分和药用价值,测定冬虫夏草口服液中的游离氨基酸和微量元素的不同种类和含量。方法：采用安捷伦1200高效液相色谱仪,C18反相柱梯度分离,邻苯二甲醛一芴甲酯柱前自动衍生化,利用已知浓度氨基酸标准品进行外标法定量,根据已知浓度氨基酸标准品的峰面积与样品峰面积之比计算游离氨基酸的含量。结果：冬虫夏草口服液中含有23种游离氨基酸和18种微量元素,氨基酸总量在口服液中占0．892％,必需氨基酸在游离氨基酸总量中占53．1％;含量最高的游离氨基酸依次是赖氨酸、亮氨酸、精氨酸。结论：游离氨基酸是冬虫夏草口服液中重要的生物有效成分,为冬虫夏草口服液的药效提供了基础数据。     

离子交换树脂用于角蒿总生物碱的纯化研究

本文以角蒿总生物碱溶液为对象,以其主要有效成分角蒿酯碱（incarvillateine）为指标,研究了阳离子交换树脂纯化角蒿总生物碱的方法,包括树脂类型的选择、氨水浓度和乙醇浓度对洗脱效果的影响.试验结果表明强酸性阳离子交换树脂DOWEX 50WX2对角蒿生物碱成分的交换能力最强,且被树脂吸附的生物碱成分可用氨性乙醇溶液快速洗脱.验证试验结果表明,用含2.0 N氨水的不同浓度乙醇溶液（60%、70%和80%）进行洗脱,得到的总生物碱含量均在60%以上,且随着乙醇浓度的提高,总生物碱的含量也不断提高.     

带血与排血梅花鹿茸骨片游离氨基酸含量的比较分析

选用6对带血与排血梅花鹿茸骨片对其游离氨基酸的含量进行了对比测定,结果表明含有7种必需氨基酸,必需氨基酸所占比例约30%,必需与非必需游离氨基酸之比约0.4。对两者进行方差分析,两种样品游离氨基酸总量和必需游离氨基酸总量差异不显著(P(0.05)。     

芦笋茎叶游离氨基酸的提取及含量测定

通过对芦笋茎叶游离氨基酸提取工艺中温度、提取时间、料液比、乙酸浓度等影响因素的试验分析,确定芦笋茎叶游离氨基酸测定过程中的最佳提取条件为：提取温度60℃;料液比为1：35;提取时间为2．5h;并对芦笋茎叶游离氨基酸含量进行了测定,确定芦笋茎叶游离氨基酸含量为76．54mg／100g。     

陕西朱鹮黑米酒氨基酸成份分析

采用121MB型氨基酸分析仪测定了陕西朱鹮黑米酒中的氨基酸质量浓度。结果表明:朱鹮黑米酒中含有18种氨基酸和γ-氨基丁酸,氨基酸总质量浓度为9133.5 mg.L-1,必需氨基酸占氨基酸总量的51.7%。半必需氨基酸占氨基酸总量的10%。味觉氨基酸占氨基酸总量的73.8%。与文献中报道的发酵酒氨基酸总量相比是啤酒的5倍、红葡萄酒的5.4倍、黄酒的1.35倍、清酒2.18倍、沉缸酒的2.8倍,此外必需和半必需氨基酸的含量、味觉氨基酸含量与之比较也均为最高。     

柱前衍生反相高效液相色谱法测定绞股蓝茶叶中17种游离氨基酸含量

建立2,4-二硝基氟苯柱前衍生化-反相高效液相色谱法测定绞股蓝茶叶中17种游离氨基酸的含量。以Phenomenex Gemini NX C18(4.6mm×250mm,5μm)为分析柱,采用梯度洗脱,流动相A为0.05mol·L-1乙酸钠(pH=6.4,含0.1%N,N-二甲基甲酰胺),流动相B为乙腈-水(1∶1,v/v),检测波长为360nm,柱温35℃;经方法学考察,该方法具有良好的稳定性和重现性。测定结果表明,绞股蓝茶叶中17种游离氨基酸总量为39.79mg·g-1,其中人体必需氨基酸占游离氨基酸总量的36.57%。从氨基酸含量考虑,绞股蓝茶叶具备一定的开发利用价值。     

复合氨基酸注射液中氨基酸对山梨醇测定的影响与解决方法

复合氨基酸注射液如１１Ｓ、１４Ｓ中的氨基酸可使山梨醇的测定结果偏高６％,解决方法是将注射液通过磺酸型阳离子交换树脂柱,氨基酸成分在柱上被交换,山梨醇用水洗脱后测定。本方法对制订复合氨基酸类注射液的质量标准与确保产品质量均具有实际应用价值。     

不同生长温度对烟草叶片游离氨基酸含量及脯氨酸和苯丙氨酸代谢的影响

游离氨基酸是烟叶中的重要化合物,它很大程度上影响着烟叶的品质和风味。为了解不同生长温度对烟叶中游离氨基酸的含量及其代谢的影响,通过人工气候室设置均温18.5℃、23.5℃和28.5℃3个动态气温条件,在烟叶从早期生长至成熟的整个时期进行不同生长温度处理,用分光光度法、气相色谱-质谱法和荧光定量PCR分析,研究了不同生长温度下总游离氨基酸含量和单个游离氨基酸含量的变化规律及对脯氨酸和苯丙氨酸代谢的影响。结果表明,不同生长温度对烟叶生长发育过程中游离氨基酸总量和单一游离氨基酸含量有明显影响。其中,随着烟叶生长发育的进行,所含游离氨基酸含量逐渐下降。在不同生长温度处理下,随生长温度升高总游离氨基酸含量下降;各游离氨基酸含量基本上也随生长温度的升高而降低。对脯氨酸代谢相关酶(P5CS,OAT,ProDH)活性以及苯丙氨酸代谢相关酶(PAL,C4H)活性及其基因表达的定量研究表明,其酶活性和基因表达的变化与含量变化的趋势一致。上述研究结果表明,随着烟叶的生长发育和成熟,其游离氨基酸含量逐渐降低,而较低的生长温度有利于烟叶维持较高的游离氨基酸水平。     

烤烟不同部位叶片中主要含氮化合物的变化

目的：分析烤烟下、中、上3个部位调制后叶片中烟碱、蛋白质及游离氨基酸等主要含氮化合物含量的变化规律。方法：选取3个部位烟叶分别采收烘烤5次,分级后取样测定。结果：随着烟叶部位的上升,叶片中的烟碱含量表现出随之增加的变化规律,蛋白质含量表现为＂∧＂型的变化,游离氨基酸含量表现为随之降低的变化规律。3个烟叶部位之间烟碱、蛋白质、游离氨基酸含量的差异均不显著。结论：烟叶中烟碱与蛋白质含量之间呈极显著负相关（r=-0.72）,与游离氨基酸含量之间呈显著负相关（r=-0.6）;蛋白质与游离氨基酸含量之间呈显著正相关（r=0.62）。     

烟草花叶病毒运动蛋白cDNA的克隆及融合蛋白的表达

从烟草花叶病毒(TMV)中提取总RNA,通过反转录PCR (RTPCR) 扩增得到其运动蛋白(MP)的基因,将扩增产物克隆到pMD18T载体上。DNA序列分析表明,所得到的运动蛋白的基因全长为807bp (GenBank接受号AY300161), 与已发表TMV序列（GenBank登陆号为NC-001367）和同属的番茄花叶病毒（ToMV, GenBank登陆号为NC-002692相比核苷酸的同源性分别为98.0％和80.9％,氨基酸的同源性分别为99.1％和80.0％。 将目的片段亚克隆到表达载体pET30a上,并在大肠杆菌JM109中诱导表达,诱导9h 后,融合蛋白表达量最大。诱导后的工程菌超声后经SDSPAGE检测,融合蛋白以可溶形式存在。     

Utilization of milk amino acids for body gain in suckling mink (Mustela vison) kits

The efficiency of utilization of milk amino acids for body gain in suckling mink kits from small (n = 3), medium (n = 6) and large litters (n = 9) was investigated by using 36 mink dams and their litters for measurements during lactation weeks 1 through 4. Measurements on each dam and litter were performed once, hence three dams per litter size each week (n = 9). Individual milk intake of kits was determined, milk samples were collected and kits were killed for determination of amino acid composition. The most abundant amino acids in milk were glutamate, leucine and aspartate making up about 40% of total amino acids. Branched chained amino acids made up slightly more than 20% and sulphur containing amino acids less than 5% of total milk amino acids. In kit bodies the sum of glutamate, aspartate and leucine made up about 32% of amino acids, branched chain amino acids about 16% and sulphur containing amino acids about 4%. The amino acid composition of both milk and bodies changed as lactation progressed with decreasing proportions of essential amino acids. The ratio between body and milk amino acids was constantly over 1 only for lysine, suggesting that it was the most limiting amino acid in mink milk. Milk amino acids were efficiently utilized during week 1, ranging from 74.7% (lysine) to 42.1% (leucine), with an average for essential amino acids of 58.4%. Tendencies for improved utilization of lysine (74.7-78.2%), phenylalanine (61.0-70.0%), histidine (62.4-68.8%), arginine (61.3-70.4%) and all essential amino acids (58.4-60.2%) from week 1 to week 2 were recorded. During weeks 3 and 4, the efficiency declined, and for all essential amino acids the average utilization was 38.1% during week 4.     

Hemolymph of Anopheles stephensi from uninfected and Plasmodium berghei-infected mosquitoes. 2. Free amino acids.

Determinations were made of free amino acids in hemolymph collected from adult female Anopheles stephensi mosquitoes. The hemolymph first was fractionated by extraction and precipitation procedures, after which qualitative determinations of free amino acids were made by high voltage thin layer electrophoresis, and thin layer chromatography. Subsequent quantitative determinations were made with an automatic amino acid analyzer. The concentration of total free amino acids in the hemolymph rose 60--70% after the mosquito took a blood meal, and remained relatively constant thereafter. When mosquitoes took a blood meal infected with the rodent malaria parasite Plasmodium berghei, the rise in total free amino acids was only 15--25%. The chief differences that occurred with individual free amino acids was that infected mosquitoes had greater increases in arginine, greater decreases in valine and histidine, and a total loss of detectable methionine.     

Effects of NaCl-salinity on amino acid and carbohydrate contents of Phragmites australis

The effects of NaCl-salinity on growth, free amino acid and sugar content and composition were assayed in roots, rhizomes and leaves of Phragmites australis (Cav.) Trin. ex Steud. Juvenile plants produced from freshwater clones, were cultured under greenhouse hydroponic conditions for 21 days. Relative growth rates were highest at a salinity level of 0 and 1.5‰, respectively, but decreased significantly at 10‰. All plants cultured at 35‰ salinity died. The osmolality in rhizomes and leaves increased with salinity. The total contents of free amino acids were highest in rhizomes>leaves>roots. In rhizomes, the amino acid content increased significantly up to four-fold from 0 to 10‰ salinity. This increase was caused by up to 200-fold increase of proline and 11-fold increase of glutamine at 10‰, whilst the share of asparagine and glutamate decreased. Leaves showed a similar response to salinity with increasing amino acid contents, and shares of proline and glutamine whereas roots did not react significantly. The contents of sucrose, glucose and fructose were highest in leaves>rhizomes>roots. In rhizomes of all three clones, the sugar contents increased up to 3.5-fold from 1.5 to 10‰ salinity level, but were lower at 1.5‰ versus the control (0‰). Sugar contents were lowest (roots) and highest (leaves) at 1.5‰ salinity. The sugar composition did not vary significantly except for leaves where the fraction of sucrose decreased with increasing salinity level at all three clones from 89.1 to 61.7% of total dissolved sugar (pooled data). The importance of free amino acids and sugars as osmolytes was similar in rhizomes and leaves (13–15% of total osmolality at 10‰). In rhizomes, free amino acids were more important as osmolyte than sugars, while the opposite was true for leaves. Proline contributed up to 2.7% to total osmolality. It is hypothesised that a strong proline accumulation indicates the exceeding of a critical salinity level.     

Amino acid composition of aragonitic concholin in the shell of Arctica islandica

Haugen, J. E. & Sejrup, H. P. 1990 04 15: Amino acid composition of aragonitic conchiolin in the shell of Arctica islandica. Lethaia , Vol. 23, pp. 133–141. Oslo. ISSN 0024–1164.
The distribution of amino acids within the two aragonitic shell layers of modern specimens of the mollusc Arctica islandica (Linné) has been studied in detail. The mean total hydrolyzed amino acid content was 19 nmol*mg in the inner layer and 15 nmol/mg in the outer layer. No significant difference in amino acid composition could be found between the two layers. The layers contained minor amounts of free amino acids which made up 0.3–0.7% of the total hydrolyzed amino acid content. The composition of the free amino acid fraction was very similar in each of the two layers, but differed somewhat from the total hydrolyzed fraction. The total hydrolyzed fraction was dominated by aspartic acid, glycine. alanine and glutamic acid, which together made up 62% of the total amount of amino acids, whereas the free fraction was dominated by Asp. Ser, Gly and Tyr. Amino acid content and composition within a single layer showed little variation from umbo to the ventral margin. The amino acid composition is in accordance with previously reported data on similar mineral structures which support the theory of structure specific rather than species specific amino acid composition. * Arctica islandica. amino acids. shell structure .     

Production of (10E,12Z)-conjugated linoleic acid in yeast and tobacco seeds

The polyenoic fatty acid isomerase from Propioniumbacterium acnes (PAI) was expressed in E. coli and biochemically characterized. PAI catalyzes the isomerization of a methylene-interrupted double bond system to a conjugated double bond system, creating (10E,12Z)-conjugated linoleic acid (CLA). PAI accepted a wide range of free polyunsaturated fatty acids as substrates ranging from 18:2 fatty acids to 22:6, converting them to fatty acids with two or three conjugated double bonds. For expression of PAI in yeast the PAI-sequence encoding 20 N-terminal amino acid residues was altered for optimal codon usage, yielding codon optimized PAI (coPAI). The percentage of 10,12-CLA of total esterified fatty acids was 8 times higher in yeast transformed with coPAI than in cells transformed with PAI. CLA was detected in amounts up to 5.7% of total free fatty acids in yeast transformed with coPAI but none was detected in yeast transformed with PAI. PAI or coPAI under the control of the constitutive CaMV 35S promoter or the seed-specific USP promoter was transformed into tobacco plants. CLA was only detected in seeds in coPAI-transgenic plants. The amount of CLA detected in esterified fatty acids was up to 0.3%, in free fatty acids up to 15%.     

湖南道地白芷氨基酸含量与组成分析

白芷是我国常用中药材的一种,关于白芷镇痛的有效成分,主要认为是异欧前胡素、欧前胡素等香豆素类具有解痉、镇痛等作用的挥发油类化学成分,但白芷镇痛的成分及其机理尚不十分清楚,是否有其他物质也具有一定的药理作用也不得而知,比如说某些药效性氨基酸。该研究采用自动氨基酸分析仪测定了湖南道地茶陵白芷的蛋白质类氨基酸和游离氨基酸的含量,并分析其氨基酸组成。结果表明:总氨基酸检出除Asn以外的其他16种蛋白质氨基酸,含量最高的Arg占总氨基酸的31.21%,接近1/3;必需氨基酸总量达27.01%,其中含量最高的是Leu,占总必需氨基酸的24.14%;药效氨基酸比例较高,在酸水解产物总氨基酸和游离氨基酸中分别达到73.89%和85.78%,其中Arg的含量最高,达1.383g·100g-1,占比为42.24%,游离氨基酸中γ-氨基丁酸、鸟氨酸含量也较高。此外,还含有少量的高半胱氨酸和鹅肌肽等游离非蛋白质氨基酸和短肽;必需氨基酸的组成接近WHO/FAO的建议摄入值,但Met+Cys的RC值最小,为第一限制性氨基酸。这些药效性氨基酸和游离氨基酸可能是茶陵白芷具有良好药效的一个因素,而且茶陵白芷的氨基酸组成和配比较合理、符合人体需要,在强化含硫氨基酸的基础上具有开发成为新型药食同源保健性食品的潜力。研究结果可为进一步研究白芷的药理作用提供依据。     

Contribution of Bacterial Cell Wall Components to DOM in Alkaline,Hypersaline Mono Lake,California

Soda lakes are often characterized by high densities of prokaryotes and high concentrations of dissolved organic carbon. Since bacterial cell walls are less degradable than most other cell constituents, accumulation of cell wall material may occur in these lakes and contribute to the DOM pool, but composition of DOM in soda lakes has rarely been examined. Here we report concentrations of DOM components likely originating from bacterial cell walls, including D amino acids, glucosamine (GluA) and muramic acid (MurA), in depth profiles of stratified, alkaline, hypersaline Mono Lake, CA. Concentrations of cell wall components were related to total pools of dissolved free and combined amino acids (DFAA and DCAA), and bacterial density and production. In the free pool, total DFAA ranged from 50 to 3250 nM and typically increased with depth, while GluA (5 to 140 nM) and MurA (< 0.5 nM and only detected in 2005) fluctuated with depth. In the combined pool, DCAA varied between 5000 and 15000 nM and did not show clear depth-related trends. GluA ranged from 1000 to 5000 nM and tended to increase in the hypolimnion, while MurA varied between 25 and 75 nM. Free D isomers in the DFAA pool either made up < 13% (Asp and Ser) or varied from 10 to 57% (Glu and Ala). In the combined pool, D isomers of Asp, Glu, Ser and Ala made up 24-48% of these DCAA and typically showed minor changes with depth. In 2005, lysozyme activity had highest rates in the surface and correlated negatively with most D isomers among the combined amino acids. Our observations demonstrate that the pool of dissolved combined amino compounds in the lake was about 5-fold higher than in other eutrophic lakes and that a substantial portion of these amino compounds originated from bacterial cell walls.     

Composition and Distribution of Free Amino Acids in Flatpea (Lathyrus sylvestris L.) as Influenced by Water Deficit and Plant Age

Drought-stressed flatpea (Lathyrus sylvestris L.) plants from8 to 22 weeks old were analysed for nitrogen, soluble proteinand free amino acids. An increase in nitrogen and free aminoacid concentrations and a decrease in soluble protein levelwere observed in roots of plants up to 16 weeks old. The cumulativeconcentration of free amino acids increased with drought stress.Tissue concentrations of 2, 4-diaminobutyric acid (1.6–2.6%of the dry weight) were highest in leaves. Levels increasedsteadily, nearly doubling, in leaves and stems between weeks10 and 16. Levels in drought-stressed leaves were, on average,11.9% higher than those of controls. Estimated concentrationsof a mixture of 4-aminobutyric acid and an unknown amino acidwere highest in stems, increased in this tissue with age andtended to increase in stems and leaves and decrease in rootsin response to water deficit. Levels of the mixture of homoserineand another unidentified amino acid were not influenced by ageor water status of the plants. Root concentrations of asparagine,arginine, glutamine, aspartate, and another prominent, unidentifiedamino acid increased with plant age and reached a peak at thetime of flowering (14 to 18 weeks). Only the concentration ofthe unknown compound was elevated following drought stress.Concentrations of valine, isoleucine, leucine, phenylalanine,and methionine also increased during this period and were elevatedin drought-stressed plants. Proline levels increased with plantage and drought stress, but proline accounted for only about10% of the total free amino acids in the drought-stressed plants. Key words: 2, 4-Diaminobutyric acid, drought, flatpea     

FREE AMINO ACID CHANGES DURING GERMINATION OF TELIOSPORES OF THE WHEAT BUNT FUNGUS,TILLETIA CARIES

Teliospores were aerated and agitated in a mineral salts medium and their free amino acid contents were analyzed at eight different times, from shortly after imbibition of water until just before germ tube emergence. In addition to the common amino acids, eight unidentified ninhydrin-positive components were detected. About 50 % or more of nearly each of the amino acids diffused out of the spores during the initial phase of germination. These released amino acids were actively taken up by the spores during the latter stages of germination. The free amino acids in largest amounts in the dormant spores of T. caries were arginine 15.0, glutamic acid 6.3, and alanine 3.7 μmoles per g dry spores. Together these three amino acids accounted for about 71 % of the total free amino acids in dormant spores of T. caries and T. controversa. The total amounts of free amino acids in spores of common bunt were much higher than in spores of dwarf bunt.