Accq.Tag法测定氨基酸口服液的氨基酸含量

采用AccQ .Tag法对氨基酸口服液中游离氨基酸和牛磺酸含量进行了分离测定。产品中氨基酸总量达 85mg/ml以上 ,共 1 3种氨基酸。必需氨基酸与非必需氨基酸比例为 2 .2 0～ 2 .50∶1 ,支 /芳比为 2 .30～ 2 .55∶1 .配方接近于FAO氨基酸比例模式 ,以FAO氨基酸模式及化学评分评价了该制剂的营养价值 ,基本上不存在限制氨基酸 ,化学评分均在 90分以上。     

大杯香菇辐射新株系各类氨基酸的遗传主成分分析

对大杯香菇辐射选育新株系的各类氨基酸总量进行了遗传主成分分析。结果表明,变异系数最大的为硫氨基酸总量,达到13．39％;其次为儿童氨基酸总量,变异系数为7．00％;其它变异系数较小分别为甜味氨基酸总量、芳香族氨基酸总量、必需氨基酸总量、支链氨基酸总量和鲜味氨基酸总量为5．69％、5．64％、5．19％、5．24％和5．06％;在相关性上,鲜味氨基酸总量与甜味氨基酸总量、支链氨基酸总量、芳香族氨基酸总量、儿童氨基酸总量和必需氨基酸总量是呈极显著和显著的正相关,甜味氨基酸总量与支链氨基酸总量、儿童氨基酸总量和芳香族氨基酸总量呈极显著和显著的正相关,硫氨基酸总量与儿童氨基酸总量呈极显著负相关,与必需氨基酸总量是呈极显著正相关;支链氨基酸总量与芳香族氨基酸总量、必需氨基酸总量是呈极显著,与儿童氨基酸总量呈显著正相关;芳香族氨基酸总量与儿童氨基酸总量和必需氨基酸总量是呈极显著和显著的正相关;主成分分析结果表明,前4个特征根在7个特征根中累计贡献率达97．14％,也就是前4个主成分对变异的贡献率达96．07％。在各类氨基酸总量指标选择上,首先对变异大的各类氨基酸总量进行选择是及其重要的。在辐射选育新株系选择时,应注意选择大杯香菇中硫氨基酸总量高的新株系。     

Metabolism of n-3 polyunsaturated fatty acids and modification of phospholipids in cultured rabbit aortic smooth muscle cells

The metabolism of the linolenic acid family (n-3) of fatty acids, e.g., linolenic, eicosapentaenoic, and docosahexaenoic acids, in cultured smooth muscle cells from rabbit aorta was compared to the metabolism of linoleic and arachidonic acids. There was a time-dependent uptake of these fatty acids into cells for 16 hr (arachidonic greater than docosahexaenoic, linoleic, eicosapentaenoic greater than linolenic), and the acids were incorporated mainly into phospholipids and triglycerides. Eicosapentaenoic and arachidonic acids were incorporated more into phosphatidylethanolamine and phosphatidylinositol plus phosphatidylserine and less into phosphatidylcholine than linolenic and linoleic acids. Docosahexaenoic acid was incorporated into phosphatidylethanolamine more than linolenic and linoleic acids and into phosphatidylinositol plus phosphatidylserine less than eicosapentaenoic and arachidonic acids. Added linolenic acid accumulated mainly in phosphatidylcholine and did not decrease the arachidonic acid content of any phospholipid subfraction. Elongation-desaturation metabolites of linoleic acid did not accumulate. Cells treated with eicosapentaenoic acid accumulated both eicosapentaenoic and docosapentaenoic acids mainly in phosphatidylethanolamine and the arachidonic acid content was decreased. Added docosahexaenoic acid accumulated mainly in phosphatidylethanolamine and decreased the content of both arachidonic and oleic acids. The following conclusions are drawn from these results. The three n-3 fatty acids are utilized differently in phospholipids. The arachidonic acid content of phospholipids is reduced by eicosapentaenoic and docosahexaenoic acids, but not by linolenic acid. Smooth muscle cells have little or no desaturase activity, but have significant elongation activity for polyunsaturated fatty acids.     

泰和乌骨鸡肌肉氨基酸营养价值的研究

泰和乌骨鸡肌肉含有18种氨基酸,总量为20.63%,其中8种人体必须氨基酸总量为8.30%,4种鲜味氨基酸总量为8.96%。必须氨基酸在总氨基酸中所占的百分比高于WHO/FAO模式,必须氨基酸的构成比例基本符合WHO/FAO标准     

饲养中国大鲵氨基酸组成分析

实验对饲养中国大鲵氨基酸组成成分进行了比较全面的测定与分析,结果表明:饲养中国大鲵肌肉的蛋白质质量分数为164.3 g.kg-1,水解氨基酸总量为160.6 g.kg-1,各种氨基酸组成相当全面,必需氨基酸(EAA)为75.2 g.kg-1,占氨基酸总量的46.82%,符合人体需要量模式的程度相当高,为优质食物蛋白,可与做为参考蛋白的鸡蛋蛋白相媲美。研究同时发现呈味氨基酸总量70.5 g.kg-1,占氨基酸总量的43.90%,为研发味道鲜美的大鲵食品提供了有力的数据。     

Fatty acid production from amino acids and alpha-keto acids by Brevibacterium linens BL2

Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and alpha-keto acids is one mechanism to generate these flavorful compounds; however, metabolism of alpha-keto acids to flavor-associated compounds is controversial. The objective of this study was to determine the ability of Brevibacterium linens BL2 to produce fatty acids from amino acids and alpha-keto acids and determine the occurrence of the likely genes in the draft genome sequence. BL2 catabolized amino acids to fatty acids only under carbohydrate starvation conditions. The primary fatty acid end products from leucine were isovaleric acid, acetic acid, and propionic acid. In contrast, logarithmic-phase cells of BL2 produced fatty acids from alpha-keto acids only. BL2 also converted alpha-keto acids to branched-chain fatty acids after carbohydrate starvation was achieved. At least 100 genes are potentially involved in five different metabolic pathways. The genome of B. linens ATCC 9174 contained these genes for production and degradation of fatty acids. These data indicate that brevibacteria have the ability to produce fatty acids from amino and alpha-keto acids and that carbon metabolism is important in regulating this event.     

Composition of long chain bases in ceramide of the guinea pig Harderian gland.

Ceramide of the guinea pig Harderian gland was isolated and characterized. The purified ceramide gave two spots on thin-layer chromatography. Ceramide with the higher Rf value (NHCer) contained non-hydroxy fatty acids and that with the lower Rf value (HCer) contained 2-hydroxy fatty acids. The ratio of NHCer to HCer was 6:1. The non-hydroxy fatty acids of NHCer were composed of straight-chain acids (94.9%) and branched-chain acids (5.1%). The 2-hydroxy fatty acids were also composed of straight-chain acids (94.2%) and branched-chain acids (5.8%). The ratio of straight-chain acids to branched-chain acids was similar in NHCer and HCer. The long chain bases of NHCer and HCer consisted of straight chain sphinganines and sphingenines, and methyl-branched long chain bases. In NHCer, 59.9% of the total bases were methyl branched, and in HCer, 48.3%. The characteristics of ceramide, that is, the large amount of methyl-branched long chain bases and relatively small amount of methyl-branched fatty acids, are similar to those of cerebroside and sphingomyelin isolated from the same organ, although the ratios of constituents are different among these sphingolipids.     

Metabolism and compartmentation of endogenous fatty acids in aged mouse liver mitochondria

Isolated mouse liver mitochondria were loaded with endogenous free fatty acids by aging in vitro. The oxidation and compartmentation of these fatty acids was studied. ATP-supported carnitine-dependent and carnitine-independent oxidation pathways of about equal activity were identified. The carnitine-dependent activity was abolished by nagarse and tetrathionate. It was also absent in mitoplasts. Hence the endogenous pool of free fatty acids which served as substrate for this pathway was located in the outer membrane. The carnitine-independent pathway was strongly inhibited by low concentrations of atractyloside suggesting that a pool of fatty acids located in the inner membrane was utilized. The occurrence of free fatty acids in the outer and inner membranes was confirmed by direct assay. The endogenous respiratory activity was also stimulated by oligomycin which was insensitive to nagarse, atractyloside, carnitine, and ATP suggesting that the stimulation was due to utilization of endogenous ATP and fatty acids localized within the inner membrane. Bovine serum albumin preferentially reduced the carnitine-independent activity presumably by binding the endogenous fatty acids suggesting that albumin has a higher affinity for free fatty acids of the inner than of the outer membrane.     

珠子参地上部分氨基酸测定及营养评价

对珠子参茎、叶、花的氨基酸组成与含量进行测定和营养评价分析.结果表明,珠子参茎、叶、花中均含有17种常见氨基酸,氨基酸总量分别为3.73％,14.80％和8.72％;珠子参的茎中必需氨基酸与总氨基酸的比值(E/T)为0.39,必需氨基酸与非必需氨基酸的比值(E/N)为0.64,叶中E/T为0.41,E/N为o.71,花中E/T为0.39,E/N为0.63,氨基酸配比较为合理;珠子参茎、叶、花中蛋氨酸+胱氨酸均为第一限制氨基酸;珠子参茎、叶、花中均含有γ-氨基丁酸,含量分别为0.12％,0.26％和0.16％,叶片中γ-氨基丁酸的含量最高.     

Energy-driven uptake of humic acids by Aspergillus niger.

The uptake of humic acids by mycelia of Aspergillus niger was demonstrated to be energy-dependent with a sensitivity to sodium azide and to 2,4-dinitrophenol. Greater uptake of humic acids by submerged mycelium occurred at pH 3.0 and at 32 degrees C. The rate of uptake was influenced by the concentration of humic acids with an apparent Km of 0.2 grams/ml and with a Vmax of 0.13 mg humic acids per gram mycelial dry weight.10 min-1. In the absence of added energy source, Vmax of 0.05 mg humic acids per gram mycelial dry wt.10 min-1 was obtained; however, the affinity for humic acids by this uptake system was the same as for the energy-driven process. Apparent binding of humic acids to cell structures was indicated because only 41.8% of the humic acids taken up by the energy-dependent system could be recovered.     

Role of fatty acids in growth-promoting effect of serum albumin on hamster cells in vitro

Dialyzed serum albumin had considerable growth-promoting effect on cultivated hamster cells. This effect was virtually lost on removal of the fatty acids, and it was completely restored by recombination of the fatty acid-free albumin with the isolated and purified fatty acids. The role of albumin itself appeared to be largely that of a carrier of fatty acids, protecting the cells against toxic effects of fatty acids in free solution. This conclusion was based on two observations: Fatty acids in the absence of albumin were growth-inhibitory except in extremely dilute solutions, and beta-lactoglobulin, a protein possessing, like albumin, the ability to bind and release fatty acids, could replace albumin in the presence of fatty acids with similar growth-promoting effect. Examination of individual molecular types of fatty acids showed that all unsaturated acids tested were growth-promoting, whereas the saturated acids were growth-inhibiting, with the exception of stearic acid in low concentrations. Although the possibility of a mitotic triggering effect was not excluded, the fatty acids presumably stimulated growth by providing substrate for cellular metabolism, since there was a direct relationship between the degree of growth stimulation and the duration of exposure of cells to the fatty acids.     

黄粉虫蛹的营养成分分析

采用现代分析技术手段对黄粉虫Tenebrio molitor（L．）蛹的营养成分进行分析,结果表明：其蛋白质、粗脂肪、碳水化合物及灰分含量分别为鲜重的16．8％、7．6％、1．2％、1．4％,其氨基酸和胆固醇含量分别为18.7mg／g和0．4mg／g;含有7种人体必需氨基酸,其必需氨基酸占总氨基酸含量的44．40％,必需氨基酸与非必需氨基酸含量的比值为79.8％,第一限制性氨基酸为含硫氨基酸,即蛋氨酸和胱氨酸;同时,其不饱和脂肪酸与必需脂肪酸分别占总脂肪的73．9％和24．1％,特别是油酸和亚油酸含量较高,分别达49．8％和23．4％：另外,该昆虫还含有K、Ca、Mg、Fe、Zn、Cu、Mn等多种矿物质和微量元素。     

蔬菜腌制过程中的氨基酸组成变化

在腌制过程中,芥菜的精氨酸和组氨酸等碱性氨基酸含量和氨基酸总量逐渐减少,酸性氨基酸和疏水性氨基酸含量增加。在各种氨基酸中,苏氨酸含量最高,占４４．７４％,其次是谷氨酸和丙氨酸。在腌制后,芥菜的氨基酸组成发生了显著的变化,苏氨酸下降幅度最大,而蛋氨酸、苯丙氨酸、亮氨酸、异亮氨酸、缬氨酸和赖氨酸等必需氨基酸摩尔组分显著提高。理想氨基酸模式谱的相关系数腌制前为０．０６０１７,腌制２１６小时后增到０．４９９７８,表明腌制加工可显著提高蔬菜蛋白质的营养效价。     

Fluorescence analysis of photoinduced degradation of ecotoxicants in the presence of humic acids.

The photolysis of humic acids and phenols in water containing humic acids was investigated. Humic acids extracted from peat (Vasuygan Bog, Tomsk Region, Russian Federation) induce the phototransformation of 4-chlorophenol at 365 and 222 nm. Humic acids were characterized by UV-, fluorescence-, IR- and EPR-spectroscopy and laser-induced fluorescence. The influence of humic acids on the phototransformation of phenols in different irradiation conditions was investigated. Comparison of the data on mercury lamp irradiation showed that the most effective phenols degradation was observed under exposure to KrCl* exilamp light (lambda = 222 nm) in the presence of humic acids.     

基于游离氨基酸的组分及特征比较四种食用菌与四种果蔬的营养与风味特征

为科学评价食用菌与果蔬两类食材的营养特征与口感风味,本研究选取4种常见食用菌（金针菇、斑玉蕈、香菇、双孢蘑菇）和4种常见果蔬（苹果、香蕉、胡萝卜、番茄）,采用氨基酸自动分析仪测定其游离氨基酸,系统比较了两类食材的游离氨基酸组分比例及呈味特征。主成分和聚类分析表明 4种食用菌和4种果蔬显著分为两类,食用菌类游离氨基酸总量平均是果蔬类的3倍以上,4种食用菌中各游离氨基酸的比例均衡。4种食用菌的必需氨基酸/(必需氨基酸+非必需氨基酸)在40%左右,必需氨基酸/非必需氨基酸接近或大于60%,均接近理想值。4种食用菌所含的呈味氨基酸（鲜味、甜味、芳香族、苦味）均是4种果蔬的2倍以上,TAV值最显著的是：谷氨酸、苯丙氨酸、甘氨酸、苏氨酸、组氨酸、赖氨酸、缬氨酸、精氨酸和丙氨酸。这些氨基酸分属在五大氨基酸家族,在食用菌与果蔬中代谢途径相同;只有赖氨酸在二者中的合成途径不同。结果表明供试的食用菌比果蔬有优质的氨基酸比例和丰富的呈味组分,此差异体现在众多氨基酸的代谢层面,而非个别氨基酸导致。     

Distribution of cis-Vaccenic Acid in Chinese Hamster V79-R Cells

V79-R Cells grown in lipid-free medium contained octadecenoic acids as the major fatty acids esterified to lipids. Octadecenoic acids were composed of two positional isomers, oleic and cis-vaccenic acids. The distribution of oleic and cis-vaccenic acids was altered by the addition of various fatty acids to the medium. There was no difference in the distribution of oleic and cis-vaccenic acids in phospholipids between mitochondria and microsomes. Cardiolipin contained higher amounts of palmitoleic and cis-vaccenic acids than did other lipids.     

Simple and rapid quantitative high-performance liquid chromatographic analysis of plasma amino acids

A simple and rapid high performance liquid chromatographic method for the determination of plasma amino acids was developed. The method uses minimal sample volume and automated online precolumn derivitization of amino acids with o-phthalaldehyde and fluorescent detection. Amino acids are separated by a simplified gradient without column heating. The assay is linear from 5 to 1000 micromol/L for all amino acids. Recovery of amino acids was between 91 and 108%, intra-assay coefficient of variation (CV) was 1-7%, and inter-assay CV was 2-12%. The simple sample preparation and minimal sample volume make the method useful for the quantitation of amino acids in both patient and experimental animal samples.     

Effect and potential ecological significance of the interaction of humic acids with two aquatic extracellular proteases

1. The effects of humic acids and fulvic acids on an extracellular serine and metalloprotease purified from a strain of Aeromonas hydrophila isolated from a freshwater wetland were examined. The serine protease was inhibited by humic acids at pH and humic acid concentrations found naturally in the wetland where this strain of A. hydrophila was isolated. The metalloprotease was not inhibited by humic acids at any pH investigated. Fulvic acids had no effect upon either protease. 2. Inhibition of serine protease activity by humic acids was reversed by increasing the pH to 9, as well as increasing the ionic strength by addition of CaCl₂- It was concluded that the interaction between humic acids and the serine protease was primarily ionic. 3. The formation of a humic acid-serine protease complex increased the half-life of enzymatic activity in dilute solutions. Humic acids had no effect on the stability of the metalloprotease. 4. There was no clear effect of humic acids on the growth of A. hydrophila, indicating that either the serine protease is not involved in the rate-limiting step of growth or that sufficient activity exists even when the serine protease is inhibited by humic acids. 5. Increasing the enzymatic lifetime through association with humic acids may be an adaptive mechanism which could result in energy conservation due to a decreased requirement for protein synthesis.     

大鼠肝线粒体中的脂肪酸分析

用双 2 乙基己基酚酞酸酯 (DEHP)诱导大鼠肝过氧化物酶体增殖 ,然后用蔗糖密度梯度离心法分离大鼠肝线粒体 ,用毛细管气相色谱法测定肝线粒体中的脂肪酸含量。测定结果 :所测 1 4种脂肪酸的总量 ,青年正常组大于青年诱导组 (P <0 .0 1 ) ,青年正常组大于老年正常组 (P <0 .0 5 )。不饱和脂肪酸与脂肪酸总量的比例 ,老年诱导组大于老年正常组 (P <0 .0 5 ) ,青年正常组大于老年正常组 (P <0 .0 5 )。长链脂肪酸与脂肪酸总量的比例 ,老年正常组小于老年诱导组 (P <0 .0 5 )。结果表明 ,用DEHP诱导大鼠肝过氧化物酶体增值 ,影响肝线粒体脂肪酸正常代谢 ,使线粒体膜结构发生变化 ,这种变化 ,青年鼠与老年鼠不同     

Gustatory responses of eel palatine receptors to amino acids and carboxylic acids

The gustatory receptors of the eel palate were found to be extremely sensitive to amino acids and carboxylic acids. The results obtained are as follows: (a) 11 amino acids which are among naturally occurring amino acids elicited responses in the palatine nerve, but 9 amino acids did not elicit a response even at a high concentration. The effect of D-amino acids was always much less than that of their corresponding L-isomers. There was no appreciable difference in the effectiveness of an alpha-amino acid (alpha-alanine) and beta-amino acid (beta-alanine). (b) The threshold concentrations of the most potent amino acids (arginine, glycine) were between 10(-8) and 10(-9) M. A linear relation between the magnitude of the response and log stimulus concentration held for a wide concentration range for all the amino acids examined. (c) The palatine receptors responded sensitively to various carboxylic acid solutions whose pH was adjusted to neutral. The threshold concentrations varied between 10(-4) and 10(-7) M. The magnitude of the response at 10(-2) M increased with an increase of carbon chain length. (d) The extent of cross-adaptation was examined with various combinations of amino acids. A variety of the response patterns showing complete cross-adaptation, no cross-adaptation, or synergetic interaction was observed. The synergetic interaction was also observed when one amino acid below its threshold concentration was added to the other amino acid below its threshold concentration was added to the other amino acid. No cross-adaptation was observed between amino acids and fatty acids. (e) The treatment of the palate with papain led to loss of the responses to arginine, glycine, and histidine without affecting those to proline and acetic acid. The treatment with pronase E eliminated selectively the response to proline. The possibility that the eel gustatory receptors are responsible for sensing food at a distance was discussed.