鱼腥草游离氨基酸组成及含量的HPLC分析

研究不同鱼腥草材料间及其两个不同采收时期游离氨基酸组成及含量差异 ,筛选游离氨基酸种类较多 ,含量较高的新品系 ,并确定适宜的采收时期。对 1 9份鱼腥草材料阴干地上部分游离氨基酸成分进行了高效液相色谱分析。 6月和 1 0月采收的鱼腥草中分别含有 1 5种和 1 4种氨基酸 ,都不含Cysteine -ss -Cysteine和Lysine,1 0月采收的还不含有Tyrosine。氨基酸中Proline含量最高 ,Glycine含量最低。此外 ,1 0月采收的鱼腥草的游离氨基酸总量高于 6月采收的鱼腥草。供试材料中 6月采收的W0 1 - 86和 1 0月采收的W0 1 - 5多数游离氨基酸含量均为同一采收时期的最高值。分别为 5 894 .76mg/kg和 6 1 6 6 .1 3mg/kg。此外 ,蕺菜与峨眉蕺菜间游离氨基酸成分间无显著差别。因此鱼腥草不同材料间及不同采收时期游离氨基酸含量不尽相同 ,游离氨基酸含量与染色体数目间相关不显著     

烟草叶片游离氨基酸含量的分析

分析结果表明,烟草叶片中含有１６种以上游离氨基酸,其中谷氨酸含量最高。不同层次叶片的总游离氨基酸含量不同,从脚叶（下层）至顶叶（上层）总游离氨基酸的含量逐渐增加。此外,烟草叶片中尚含有芳香族氨基酸,其中苯丙氨酸与酪氨酸对烟叶色、香、味的形成起着重要作用。     

银杏叶中氨基酸的含量测定

本文测定了不同时期采集的银杏树叶中１７种氨基酸的含量。结果表明,银杏叶中水解氨基酸的总含量分别为１５．０９％,１１．８７％,９．９７％,和７．１４％;游离氨基酸的总含量分别为０．７６％,０．２８％。     

健康学龄前儿童血浆氨基酸与血红蛋白含量

本文采用丹酰氯聚酰胺薄层分析法研究了６５名３—７岁健康儿童的血浆游离氨基酸和血红蛋白浓度。结果表明：（１）赖氨酸促进蛋白质合成不仅供机体生长需要,同样也供合成血红蛋白;（２）贫血前期已有血浆游离氨基酸的变化,继而出现贫血,提示儿童时期生长旺盛,应注重补充某些氨基酸消耗和补充维生素、叶酸、铁元素等造血原料。     

先天性与后天性大鼠白内障晶体中游离氨基酸含量变化的研究

用药和的诱发大鼠先天性白内障动物模型,检测了晶体中１８种游离氨基酸含量,并与大鼠硒性和半乳糖性白内障晶体中ＦＦＡ含量进行了比较,发现：仔一代和仔二代先天性白内障晶体中各ＦＡＡ含量接近,先天性白内障晶体内,酪氨酸和羟脯氨酸含量明显高于正常对照组（Ｐ＞０．０５）;谷氨酸、甘氨酸等９种ＦＡＡ明显低于硒性白内障（Ｐ＜０．０５）;而酪氨酸高于半乳糖性白内障组,半胱氨酸等５种ＦＡＡ含量均低于半乳糖性白内障组。     

三种蜚蠊的游离氨基酸分析

<正> 分析生物体中游离氨基酸的组成和含量,可以了解各生物对氨基酸的需求、蛋白质代谢的特点,也是目前近代生物化学和分子分类学研究的组成部分,为此,我们对三种蜚蠊的游离氨基酸进行了分析,特报告如下。     

LC-MS测定不同品种小麦中氨基酸含量及PCA分析

小麦是世界第二大粮食作物,为人体主要蛋白的来源之一.高蛋白含量的小麦育种,同时改善其必需氨基酸的比例是当前研究热点.本文中,笔者采用LC-MS测定小麦中游离和水解氨基酸含量,并利用主成分分析(PCA)法对37个不同品种小麦中游离和水解氨基酸进行综合评价.结果表明,37个小麦品种中游离和水解氨基酸种类无差异,但是含量差异...     

诺丽果与热带水果中氨基酸含量及组成对比分析

以诺丽果和16种海南常见热带水果为材料,对比分析了氨基酸含量及组成。结果表明:诺丽果含有18种氨基酸,种类齐全。其氨基酸总量、人体必需氨基酸含量和儿童必需氨基酸含量均居第1位。诺丽果的E/T值为37.13%,E/N值为0.59,符合理想蛋白质的要求。诺丽果中各种人体必需氨基酸,Val、Ile、Leu、Phe+Tyr、M et+Cys、Thr的含量占氨基酸总量的比例,与1973年FAO/WHO修订的人体必需氨基酸含量模式谱基本一致,仅Lys中度缺乏。诺丽果中鲜味类、芳香族、甜味类氨基酸含量居第1位。     

杭白芷根中分泌道发生方式、分布及其挥发油积累过程研究

为探明杭白芷(Angelica dahurica var.formosana)根中分泌道发生方式、分布及其挥发油转运积累特征,该研究利用光镜及透射电子显微镜技术观察分泌道发生过程及挥发油转运特征,结合组织化学定位确定挥发油的主要积累部位。结果表明:杭白芷根中分泌道由中柱鞘细胞最先发生,次生结构中分泌道主要分布在韧皮部和皮层中;挥发油的合成不仅与分泌细胞中质体及细胞质有关,而且还与周围细胞关系密切;分泌细胞内高尔基体和内质网丰富,可能先通过形成小泡参与转运,再经由细胞壁向腔道内转移;相邻分泌细胞靠近角隅处的细胞壁分泌活动活跃,腔道内积累大量电子致密物质;成熟分泌道中分泌细胞及其腔道内积累大量油滴,因此挥发油主要积累场所为分泌细胞及其腔道。该研究明确了杭白芷根中分泌道的发生方式、分布及其挥发油积累部位,揭示了分泌道发育过程中挥发油的转运积累特征,为进一步阐明分泌组织生长发育与有效成分积累关系提供了理论依据。     

杭白芷根的分泌道超微结构与其挥发油分泌的关系

利用光镜及透射电子显微镜技术研究了杭白芷根中分泌道结构及其挥发油的分泌,并重点探讨分泌道中挥发油的分泌过程。结果显示:(1)杭白芷的分泌道是由上皮细胞围绕着的伸长的胞间隙,腔道内贮存着挥发油。(2)分泌道细胞的质体、细胞基质以及线粒体参与挥发油或其前体物质的合成。(3)在分泌道发育的后期,大量小泡与分泌细胞的液泡膜和细胞质膜融合,将其内的物质释放进入空腔。研究认为,杭白芷分泌道中挥发油主要合成部位为质体及细胞基质,之后以扩散渗透或通过膜质小泡与液泡及质膜融合这两种方式分泌到空腔内,丰富的线粒体可能为这一系列过程提供能量。     

蚯蚓活动对土壤氨基酸组分及含量的影响

通过室内培养试验,研究了赤子爱胜蚓(Eisenia foetida)和威廉环毛蚓(Metaphire guillelmi)对土壤氨基酸组分及含量的影响,并探讨了两种不同生活型蚯蚓作用效果的异同。结果表明:蚯蚓活动可显著改变土壤氨基酸含量,爱胜蚓作用下土壤酸解氨基酸和游离氨基酸分别增加5.08 g/kg和7.72 mg/kg,环毛蚓作用下土壤酸解氨基酸和游离氨基酸分别增加3.86 g/kg和4.44mg/kg。各处理酸解氨基酸均以中性氨基酸所占比例为最大(平均51.9%),酸性氨基酸次之(平均23.3%),而含硫氨基酸(平均14.4%)及碱性氨基酸最少(平均10.4%)。各处理游离氨基酸同样以中性氨基酸为主,平均54.4%,而以碱性氨基酸含量最少,平均仅为7.2%。蚯蚓活动并未改变土壤氨基酸可检出种类,各处理分别检测出16种酸解氨基酸和14种游离氨基酸。土壤酸解氨基酸和游离氨基酸组分含量在蚯蚓作用下均有明显改变:加入爱胜蚓后土壤酸解氨基酸组分中天冬氨酸、精氨酸、甲硫氨酸、丙氨酸、赖氨酸和甘氨酸增幅较高,均在85.7%以上,缬氨酸、苏氨酸、丝氨酸、谷氨酸、亮氨酸、酪氨酸和组氨酸增幅较小在40.7%—62.7%间波动;加入环毛蚓后土壤酸解氨基酸组分中甲硫氨酸、赖氨酸、天冬氨酸、酪氨酸和丙氨酸增幅较大,均在71.9%以上,甘氨酸、精氨酸、异亮氨酸增幅适中,分别为56.8%、55.6%和54.9%;丝氨酸、亮氨酸、苏氨酸、谷氨酸、组氨酸和苯丙氨酸增幅最小,均在40%以下;游离氨基酸组分中组氨酸、精氨酸、甘氨酸、亮氨酸、异亮氨酸和丙氨酸在加入爱胜蚓后增加的幅度较大,增幅在150.0%以上,增幅较为缓和的氨基酸组分有天冬氨酸、苏氨酸、丝氨酸、缬氨酸、谷氨酸和苯丙氨酸,介于58.8%—92.1%之间;环毛蚓作用下,天冬氨酸、精氨酸、丝氨酸和异亮氨酸增幅最大,分别为184.2%、173.3%、163.0%和116.6%;苏氨酸、亮氨酸、缬氨酸和甘氨酸增幅较缓,介于52.3%—92.7%之间;谷氨酸、组氨酸、苯丙氨酸、丙氨酸和甲硫氨酸增幅较低,均在33.1%之下;而半胱氨酸在蚯蚓作用下显著降低,降幅为11.8%。对比两种生活型蚯蚓作用效果可知,土壤氨基酸总含量及各组分含量在爱胜蚓和环毛蚓作用下的增加或减少趋势相同(土壤酸解氨基酸组分缬氨酸除外),但改变幅度却存在明显差异,总体而言,爱胜蚓作用效果优于环毛蚓。     

基于氨基酸和二肽组成的蛋白质四级结构分类研究

基于最近邻居算法,从蛋白质一级序列出发,利用蛋白质序列氨基酸组成、二肤组成以及混合组成方法对蛋白质单聚体、二聚体、三聚体、四聚体、五聚体、六聚体和八聚体进行分类研究。结果表明:采用二肽组成编码方法的预洲效果最好,Jackknife检验和独立测试集检验的总体预测精度分别达到90.83%和95.48%,比相同数据集上基于伪氨基酸组成和组分耦合预测的方法提高了12和15个百分点;特别是对于五聚体蛋白,预测精度分别提高了90和50个百分点;说明二肽组成对于蛋白质四级结构分类研究是一种非常有效的特征提取方法。     

A sulfur amino acid deficiency changes the amino acid composition of body protein in piglets

Experiments carried out to determine the amino acid requirement in growing animals are often based on the premise that the amino acid composition of body protein is constant. However, there are indications that this assumption may not be correct. The objective of this study was to test the effect of feeding piglets a diet deficient or not in total sulfur amino acids (TSAA; Met + Cys) on nitrogen retention and amino acid composition of proteins in different body compartments. Six blocks of three pigs each were used in a combined comparative slaughter and nitrogen balance study. One piglet in each block was slaughtered at 42 days of age, whereas the other piglets received a diet deficient or not in TSAA for 19 days and were slaughtered thereafter. Two diets were formulated to provide either 0.20% Met and 0.45% TSAA (on a standardized ileal digestible basis) or 0.46% Met and 0.70% TSAA. Diets were offered approximately 25% below ad libitum intake. At slaughter, the whole animal was divided into carcass, blood, intestines, liver, and the combined head, tail, feet and other organs (HFTO), which were analyzed for nitrogen and amino acid contents. Samples of the longissimus muscle (LM) were analyzed for myosin heavy chain (MyHC) and actin contents. Nitrogen retention was 20% lower in piglets receiving the TSAA-deficient diet (P < 0.01). In these piglets, the nitrogen content in tissue gain was lower in the empty body, carcass, LM and blood (P < 0.05) or tended to be lower in HFTO (P < 0.10), but was not different in the intestines and liver. The Met content in retained protein was lower in the empty body, LM and blood (P < 0.05), and tended to be lower in the carcass (P < 0.10). The Cys content was lower in LM, but higher in blood of piglets receiving the TSAA-deficient diet (P < 0.05). Skeletal muscle appeared to be affected most by the TSAA deficiency. In LM, the Met content in retained protein was reduced by 12% and total Met retention by more than 60%. The MyHC and actin contents in LM were not affected by the TSAA content of the diet. These results show that a deficient TSAA supply affects the amino acid composition of different body proteins. This questions the use of a constant ideal amino acid profile to express dietary amino acid requirements, but also illustrates the plasticity of the animal to cope with nutritional challenges.     

4种野生蔬菜的氨基酸含量及其营养价值评价

野生蔬菜具有独特的口味,丰富的营养,有些还具有防病治病的功能,对人体有良好的保健作用.白子菜[Gynura divaricata (L.) DC.]茎叶有消热、舒筋及止血祛瘀的作用,用于镇咳、风湿性关节痛、骨折、创伤止血,痈肿疮疥等症,在民间还作抗癌草使用[1].红凤菜(Gynura bicolor DC.)茎叶有活血止血,解毒消肿的功效,治痛经,血崩,咳血,创伤出血,溃疡久不收口[2].诸葛菜[Orychophragmus violaceus (L.) Schulz]作为野生蔬菜在江苏、安徽民间有很长的食用历史,测定结果表明,该种含有黄酮类化合物[3].马齿苋(Portulaca oleracea L.)具有清热解毒、消炎、利尿、消肿的功效,民间还用于白发症、糖尿病、心血管疾病的治疗[4],中国卫生部将它列为药食同用的植物.     

鱼腥草种质资源氨基酸组成及含量分析

分别对鱼腥草16个不同居群幼嫩地上和地下部分的氨基酸成分进行高效液相色谱分析。结果发现,鱼腥草不同居群的氨基酸含量不尽相同,同一居群幼嫩地上茎叶和地下茎的氨基酸含量也有差异,多以地上茎叶高于地下茎。在分析的17种氨基酸中,所有居群均含有16种氨基酸,都不含Cys-SS-Cys。地上部分氨基酸中Glu含量最高,His含量最低;地下部分氨基酸中Glu含量最高,Tyr含量最低。地上部分氨基酸总量以W01-16为最高,而地下部分氨基酸总量以W01-99为最高,分别为27.89mg/g和15.46mg/g。蕺菜与峨眉蕺菜间氨基酸成分间无显著差别。鱼腥草种质资源氨基酸含量与染色体数目间相关不显著。     

Unique amino acid composition of proteins in halophilic bacteria

The amino acid compositions of proteins from halophilic archaea were compared with those from non-halophilic mesophiles and thermophiles, in terms of the protein surface and interior, on a genome-wide scale. As we previously reported for proteins from thermophiles, a biased amino acid composition also exists in halophiles, in which an abundance of acidic residues was found on the protein surface as compared to the interior. This general feature did not seem to depend on the individual protein structures, but was applicable to all proteins encoded within the entire genome. Unique protein surface compositions are common in both halophiles and thermophiles. Statistical tests have shown that significant surface compositional differences exist among halophiles, non-halophiles, and thermophiles, while the interior composition within each of the three types of organisms does not significantly differ. Although thermophilic proteins have an almost equal abundance of both acidic and basic residues, a large excess of acidic residues in halophilic proteins seems to be compensated by fewer basic residues. Aspartic acid, lysine, asparagine, alanine, and threonine significantly contributed to the compositional differences of halophiles from meso- and thermophiles. Among them, however, only aspartic acid deviated largely from the expected amount estimated from the dinucleotide composition of the genomic DNA sequence of the halophile, which has an extremely high G+C content (68%). Thus, the other residues with large deviations (Lys, Ala, etc.) from their non-halophilic frequencies could have arisen merely as "dragging effects" caused by the compositional shift of the DNA, which would have changed to increase principally the fraction of aspartic acid alone.     

Neutral amino acid transport in Leishmania promastigotes

Neutral amino acid transport was investigated in Leishmania promastigotes. Proline and alanine transport occur against their concentration gradient although there is a very rapid (40% at 30 min) conversion of proline to alanine. Uptake of these amino acids occurs by a sodium-independent route which is completely eliminated by addition of CCCP or KCN. $\text{K}{}_{\mathrm{<mtext>m</mtext>}}$ values for proline and alanine are 80 μM and 63 μM with $\text{V}{}_{\mathrm{<mtext>max</mtext>}}$ values of 6.4 and 7.2 nmol/min per mg dry weight, respectively. Countertransport of proline, alanine and phenylalanine was measured by loading the cells with a variety of neutral amino acids and proline analogs, followed by CCCP addition. The effect of aminooxyacetic acid, an inhibitor of alanine aminotransferase (EC 2.6.1.2), on proline and alanine countertransport was also examined. The results obtained are consistent with the presence of at least two systems for neutral amino acid transport in Leishmania promastigotes.     

柠条平茬处理后不同组织游离氨基酸含量

选择12株30年生的老年柠条作为研究对象,之后随机对6株进行平茬处理,其余6株未破坏的植株为对照,在植物旺盛生长期,对平茬后当年生萌蘖株与未破坏对照株根、茎、叶中17种常见游离氨基酸含量进行了分析比较,以期从氨基酸的角度对柠条萌蘖的再生生长进行认识。结果显示,游离氨基酸含量在对照和平茬萌蘖柠条叶和根中处理间的差异远大于茎间差异;在生长季的座荚期,萌蘖株叶中天门冬氨酸、苏氨酸、丝氨酸、丙氨酸、缬氨酸、亮氨酸、酪氨酸、组氨酸、精氨酸,根中天门冬氨酸、丝氨酸、缬氨酸、胱氨酸含量为对照株的1.5倍以上;成熟期,萌蘖株叶中天门冬氨酸、苏氨酸、丝氨酸、谷氨酸、酪氨酸、苯丙氨酸、精氨酸、胱氨酸,根中天门冬氨酸、丝氨酸、缬氨酸、组氨酸、精氨酸的含量也达到对照的1.5倍以上。脯氨酸在座荚期对照株叶和茎中含量显著高于萌蘖株,成熟期处理间差异不显著,其含量受降雨和叶含水量影响显著,在植株体内起着重要的渗透调节作用。若不计脯氨酸含量,萌蘖株的根和叶中其余16种游离态氨基酸含量之和分别是对照株的2.0和2.7倍之多。由此可见,生长季叶和根中较高的游离氨基酸含量为萌蘖柠条快速合成其地上组织和实现生物量积累提供了较好的物质条件,是平茬后柠条萌蘖株迅速再生生长的重要机制之一。