苦荞麦的氨基酸含量与营养评价

本文用氨基酸自动分析仪测定了苦荞麦粉中１８种氨基酸,其总含量为１１．７４ｇ／１００ｇ,其中有营养必需的８种氨基酸。苏氨酸为第一限制氨基酸,含硫氨基酸为第二限制氨基酸,并考查了其应用前景。苦荞麦（Ｆａｇｏｐｙｒｕｍ ｔａｔａｒｉｃｕｍ（Ｌ．）Ｇａｅｒｔｎ）属蓼科（Ｐｏｌｙｇｏｎａｃｅａｅ）,是一年生草本植物,其果实含有大量淀粉,可麻粉食用或作牧畜饲料。据文献记载,带果的全划入药,祛风湿、健胃,主治跌     

DEVELOPMENTAL CHANGES IN MOUSE BRAIN: WEIGHT, WATER CONTENT AND FREE AMINO ACIDS

Abstract— —Glutamic acid, glutamine, GABA and aspartic acid exhibited postnatal increases in the developing mouse brain at the same time that the other amino acids, both essential and non-essential, of the pool decreased. The most significant decreases were observed in the concentrations of taurine, phosphoethanolamine, glycine and alanine. The period of rapid accumulation of the members of the glutamic acid family in the mouse brain was concurrent with dramatic increases and decreases in brain weight and water content, respectively.     

LEVELS OF AMINO ACIDS AND PROTEINS IN PACINIAN CORPUSCLES OF THE CAT

Abstract— Paper chromatography of extracts from mesenteric Pacinian corpuscles of the cat revealed the presence of glutamic acid, glutamine, aspartic acid and alanine as major amino acids, and glycine, serine and threonine in traces; GABA was not detected. Levels of glutamic acid (0·75 μmol/g ' 0·37, s.d. ), glutamine (1·34 ± 0·55), and aspartic acid (0·32 ± 0·22) of mesenteric and pancreatic samples of Pacinian corpuscles were determined by separation on chromatographic columns. The protein values averaged 5·2 ± 0·66 per cant of the wet weight.
Treatment of the cats with reserpine or pargyline or deafferentation of the Pacinian corpuscles did not significantly alter these values.     

FREE AMINO ACIDS AND RELATED COMPOUNDS IN BIOPSIES OF HUMAN BRAIN

Abstract— Contents (μmol/g wet wt.) of 35 free amino acids and related compounds were measured in biopsies of human brain from ten patients. Brain specimens were frozen in liquid nitrogen within 10 sec of their removal at neurosurgery; thus, the values found should approximate those which occur in living brain.
Levels in free pools of biopsied cerebral cortex of most of the amino acids that are constituents of proteins were only 20-50 per cent of those found in autopsied cortex. The content of cystine and ethanolamine was much lower in biopsied than in autopsied cortex. Concentrations of GABA in biopsied cortex were only 20 per cent as high as those found in autopsied cortex, and levels of γ-aminobutyryl dipeptides were also significantly lower in biopsied cortex. Amounts of cystathionine in biopsied cortex varied markedly, but averaged much higher than in autopsied cortex; a single biopsy specimen of cerebellar grey matter had a cystathionine content 36-fold greater than the mean found in autopsied cerebellum.
Appreciable variability in contents among cortical biopsies was found for glycerophosphoethanolamine, phosphoethanolamine, ethanolamine, taurine, aspartic acid, glutamic acid, glutamine, and GABA, as well as for cystathionine. Whether this variability occurred between different subjects, or between different cortical areas, was not clear, although the former possibility was suggested by findings in multiple cortical biopsies from one patient.     

培养方式对纤细裸藻脂肪酸与氨基酸含量的影响

以纤细裸藻(Euglena gracilis)为实验对象,研究了培养方式对纤细裸藻生长、脂肪酸、氨基酸的影响,并探讨了可能的作用机理。结果表明,与其他培养方式相比,光诱导可提高纤细裸藻总脂肪酸、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量,分别为2.69、0.52和1.475 g/100 g;饱和脂肪酸(SFA)含量由高到低依次为异养组、光诱导组、自养组和兼养组,其中异养组含量达1.008 g/100 g;游离氨基酸含量由高到低依次为光诱导组、兼养组、异养组和自养组,分别为381.57、358.1、330.17和231.1 mg/g;兼养组必需氨基酸含量最高,为134.37 mg/g。实验结果说明光诱导培养可显著提高纤细裸藻总脂肪酸、MUFA和PUFA含量(P<0.05);异养培养可显著提高纤细裸藻饱和脂肪酸含量(P<0.05);兼养培养可显著提高纤细裸藻必需氨基酸含量(P<0.05)。研究结果为阐明纤细裸藻对不同培养方式的响应提供了科学依据,同时为其开发应用提供数据支持。     

中国葡萄属植物叶绿体DNA的提取、纯化及分子量测定

分离出纯化的叶绿体ＤＮＡ｛ｃｐＤＮＡ）,基因组的文库便能建成,特定基因便能分离,其顺序便可进一步测定。然而,我们的研究经验表明,最常用制备纯化ｃｐＤＮＡ的方法很难应用于葡萄属的种类。本文提出了一个分离和提纯葡萄属ｃｐＤＮＡ的方法,这个方法不同于其它方法主要在于：１．偏重亚硫酸钠与巯乙醇和维生素Ｃ一起加在缓冲液中,使与溶液中的氧结合,以防止游离氧氧化单宁和其它次生物质呈显色反应;２．在高盐溶液中使用加热处理,达至８５℃为止,灭活氧化酶类,消除氧化条件。用其它科属的种类,菠菜和油菜作对比,提取和纯化了葡萄属不同类型种的ｃｐＤＮＡ,均取得了较好的结果。将提纯的中国葡萄各种的ｃｐＤＮＡ,用菠菜和油菜作比较,以λＤＮＡ作对照,经限制性酶ＢａｍＨＩ,ＳａｌＩ＋ＸｈｏＩ和ＰｓｔＩ＋ＫｐｎＩ酶解,电泳分离,扫描定量,采用描图法测定了ｃｐＤＮＡ各片段的分子量,总和约１３０ｋｂ,同时测定了菠菜和油菜的ｃｐＤＮＡ分子量。     

DISTRIBUTION AND UPTAKE OF AMINO ACIDS IN VARIOUS REGIONS OF THE CAT BRAIN IN VITRO

—(1) The levels of the free amino acids were determined in five areas of the cat brain. The regional pattern was heterogeneous and fairly characteristic for each compound. (2) The uptakes of α-aminoisobutyric acid, taurine, d -aspartic acid, and l -histidine were measured in incubated slices from 31 regions of the cat CNS. Differences in uptake were found among the various areas; the regional pattern of uptake was different for each amino acid. The initial rate of uptake (5 min incubation) very often paralleled the rate at equilibrium (90 min incubation). (3) The regional correlation between distribution in vivo and uptake in vitro was good for aspartate, less so for histidine, and poor for taurine. (4) It is concluded that regional heterogeneity in exit processes, available energy, cell density, or protein content is unlikely to have decisive influence in determining regional differences in distribution and transport of metabolites; it seems that influx is the most important factor.     

UPTAKE, RELEASE AND HOMO- AND HETERO-EXCHANGE DIFFUSIONS OF INHIBITORY AMINO ACIDS IN GUINEA-PIG CEREBELLAR SLICES

Abstract— GABA, taurine and β-alanine are taken up by guinea-pig cerebellar slices by both the high-and low-affinity uptake processes, whereas glycine is taken up only by the low-affinity process. A considerable amount of labelled GABA loaded in the slice is released by unlabelled external GABA and a minute amount is released by external β-alanine, glycine and taurine. External glycine and β-alanine releases labelled glycine loaded in the slice. Labelled taurine loaded is effectively released by external taurine and β-alanine, while labelled β-alanine loaded is released only by external β-alanine.
It is suggested that hetero-exchanges which are one-directional in some cases also take place between the amino acids in addition to homo-exchanges. Therefore, high-affinity uptake processes observed with GABA and taurine could be the result of the homo-exchange diffusions, while that of β-alanine could be due to either the homo-exchange or the hetero-exchange diffusions or both.
K⁺'-evoked releases of GABA and to a lesser extent, taurine are partially dependent upon the presence of Ca⁺ in the superfusion media, whereas that of glycine and probably that of β-alanine, are not, K⁺ -evoked releases of labelled GABA and taurine are larger when loaded by their high-affinity uptake systems than by their low-affinity uptake processes. The reverse is the case with labelled glycine and β-alanine. These results do not rule out the possibility that taurine might act as a neurotransmitter in the cerebellum.     

TRANSAMINATION OF AMINO ACIDS IN HOMOGENATES OF RAT BRAIN

Abstract— The aminotransferase activity of homogenates of brains from adult and neonatal rats has been investigated. Aminotransferase activity was demonstrated wtih 15 of 22 amino acids incubated with seven keto acids. The basic amino acids exhibited little or no activity.

• 1 The greatest activity was obtained when glutamate or aspartate was incubated with α-ketoglutarate or oxaloacetate. Significant activity was also observed when the neutral aliphatic and aromatic amino acids were incubated with these two keto acids.
• 2 Activity with pyruvate was obtained principally upon incubation with glutamate and alanine. Most of the other amino acids that underwent transamination with α-ketoglutarate also did so with pyruvate, although at a lower rate.
• 3 When phenylpyruvate was added to the medium, glutamate, phenylalanine and tyrosine transaminated most actively.
• 4 Incubations with 11 amino acids and glyoxylic acid demonstrated aminotransferase activity, with glutamate and ornithine being the most active substrates.
• 5 α-Ketoisocaproate and α-ketoisovalerate accepted amino groups primarily from the branched-chain amino acids. Except for glutamate, activity with other amino acids was low or not detectable.
• 6 A comparison of aminotransferase activity in the newborn brain with that in the adult brain showed that the greatest change in activity occurred for glutamate with pyruvate or for alanine with α-ketoglutarate, these activities increasing about 10-fold from birth to adulthood; during this time activities with most other amino acids increased two- to threefold. Amino transfers from the branched-chain amino acids showed no increase with maturation, and some reactions, such as that with methionine and a number of keto acids, decreased from birth to adulthood.
• 7 Our results correspond in general to previous studies of aminotransferase activity in brain and in liver. However, our study also indicates a possible second aminotransferase acting on the branched-chain amino acids, the presence of aminotransferase activity for methionine and asparagine, and relatively high aminotransferase activity for glutamine or ornithine when incubated with glyoxylic acid rather than other keto acids. Moreover, phenylpyruvate and glyoxylate are active in amino transfers and may serve as substrates for a number of aminotransferases.

     

几种淡水蚌外套膜蛋白质氨基酸组成及部分元素分析

测定了三角帆蚌、圆背角无齿蚌、褶纹冠蚌、背视丽蚌外套膜的粗蛋白含量 ,分析了外套膜干粉的氨基酸组成 ,并采用原子吸收光谱法和等离子吸收光谱法测定三角帆蚌、圆背角无齿蚌、褶纹冠蚌外套膜的 12种元素含量。结果表明 :干燥外套膜蛋白质含量为 :三角帆蚌 4 1 34% ,圆背角无齿蚌2 2 0 3% ,褶纹冠蚌 32 14 % ,背视丽蚌 7 78%。这四种淡水蚌外套膜均含有 17种氨基酸。被测的 12种元素中 ,Cu元素含量最高 ,其次是Fe ,Mn ,Mg ,Ca ,Zn ,Cr,而Ni,Co ,Pb ,Hg等元素含量较低。这四种淡水蚌外套膜是一类优质的动物蛋白质资源。