Quantitative analysis of free amino acids and carbohydrates in spring barley anthers at different stages of maturity

The content of the carbohydrates glucose, fructose and sucrose was determined in spring barley anthers at different stages of maturity. During maturation the sucrose content of the anthers increased markedly. The following 17 free amino acids were detected in anthers of different stages of maturity: aspartic acid, glutamic acid, serine, alanine, arginine, leucine, isoleucine, lysine, α-aminobutyric acid, glutamine, proline, tyrosine, phenylalanine, valine, threonine, cystine and glycine. Quantitative analysis was only carried out in amino acids present in higher concentrations in the analysed samples. These were: aspartic acid, glutamic acid, α-aminobutyric acid, proline, serine, valine and glutamine, and a mixture of amino acids (leucine, isoleucine, valine and phenylalanine). The total content of free amino acids increased with increasing maturity of the anthers. However, not all amino acids followed contributed to this increase, but only proline, glutamic acid, aspartic acid and glutamine. A small difference was found in the variety Gopal in which the aspartic acid content did not increase significantly, but the content of the mixture of amino acids and serine did. With the exception of green anthers of the variety Firlbecks Union, proline was present in the highest concentration in all samples analysed.     

Amino Acid Requirements for the Growth of Aedes albopictus Clone C6/36 Cells and for the Production of Dengue and Chikungunya Viruses in the Infected Cells

Amino acid requirements for the growth of Aedes albopictus, clone C6/36, cells and for the production of dengue (DEN) and Chikungunya (CHIK) viruses were examined by growing the cells or the viruses in media which were deprived of one of the 20 amino acids. Cell growth was markedly inhibited when cystine was omitted from the medium, and to a lesser extent by arginine deprivation. On the other hand, omission of alanine, asparagine, aspartic acid, and glutamic acid at the same time did not affect cell growth. Marked accumulation of alanine was observed in the medium when the cells were grown for 8 days in complete medium, with concomitant depletion of aspartic acid and glutamic acid. The production of CHIK virus was inhibited markedly by omission of cystine from the medium after virus infection, while the production of DEN viruses was more affected by glycine deprivation, although cystine deprivation also inhibited virus production to a lesser extent. On the other hand, production of CHIK and DEN viruses was not affected when alanine, asparagine, aspartic acid, and glutamic acid were omitted from the medium at the same time.     

Amino acid requirements of the mosquito Culex pipiens: asparagine essential

When any of the ten “rat essential” amino acids was omitted singly from a fully-defined synthetic dietary medium, newly-hatched Culex pipiens larvae were unable to develop to the second instar. With proline omitted, development was greatly retarded and survival to the adult stage reduced. Without aspargine (but not aspartic acid) growth and development ceased in most individuals before larval-pupal ecdysis, and no adults were obtained. These twelve amino acids are considered nutritionally essential for this mosquito. With glycine omitted singly, development was markedly retarded, but survival to the adult stage was not affected; thus this amino acid is required for good growth, but these experiments do not demonstrate it as essential. Single omission of alanine, aspartic acid, cysteine, glutamic acid or amide, serine or tyrosine had virtually no effect on development and they are therefore considered nutritionally non-essential. With diets containing the twelve culex-essential amino acids only, very little development occurred, but augmentation with either glycine or serine allowed growth and development almost as good as with the complete amino acid mixture. Augmentation of the essential twelve with alanine, cysteine, glutamic acid/amide, or tyrosine singly failed to improve development. The requirement for dietary asparagine shown by these studies appears to be unique among insects so far studied. In particular, another mosquito, Aedes aegypti, has no such requirement.     

Variation in the free amino acid content of skeletal muscle of Ophicephalus punctatus (Bloch)

The skeletal muscle of Ophicephalus punctatus contains nine essential free amino acids, arginine, histidine, isoleucine, leucine, methionine, phenylalanine, threonine, valine and lysine, and eight non-essential amino acids, alanine, aspartic acid, cystine, glutamic acid, glycine, tyrosine, proline and serine. Histidine and lysine dominated the free amino acids pool. Seasonal variation was detected in the levels of histidine, arginine, leucine, phenylalanine, glycine, cystine and serine with highest values occurring in April and again in November. Changes were also detected in the concentrations of certain amino acids as the fish grew in size. Levels of free amino acids did not significantly differ between sexes. Factors effecting variation are discussed.     

The effect of altered lipid composition on the transport of various amino acids in Candida albicans.

Candida albicans cells grown on alkanes of different chain lengths (C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, and C₁₈) exhibited a low growth rate and gradual increase in the total lipid content with the increase in the length of alkanes. There was a significant change in the phospholipids and sterols content of various alkane-grown cells compared to glucose-grown cells. In glucose-grown cells, the transport of various amino acids, e.g., proline, glutamic acid, lysine, glycine, phenylalanine, serine, methionine, and leucine was found to be energy dependent and against a concentration gradient. In alkane-grown cells, the transport of lysine, proline, serine, and methionine was reduced, however, there was no effect on the uptake of glycine, glutamic acid, phenylalanine, and leucine. The results were interpreted as different carrier(s) responsible for amino acid uptake responsed differently to the change of lipid environment.     

Growth, D-glucose utilization and malolactic fermentation by Leuconostoc œnos strains in 18 media deficient in one amino acid

Six Leuconostoc œnos strains were used to study the effect of the deficiency of one amino acid on growth, heterofermentative pathway and malolactic fermentation. All strains had an absolute requirement for four amino acids (isoleucine, glutamic acid, tryptophan and arginine) and needed six other amino acids (valine, methionine, cysteine, leucine, aspartic acid and histidine) for optimum growth. Each deficiency in one amino acid had a particular effect on D-glucose utilization. Overproduction and underproduction of D-lactic acid were observed. The rate of L-malic acid consumption in media deficient in one amino acid was lower than in the complete medium with all amino acids.
Although some deficiencies (glycine, phenylalanine, proline or tyrosine) had no influence on the growth, they noticeably limited the malolactic fermentation.     

Amino acids and growth substances in barley root excretions (Hordeum distichon L.) and their biological effect

The biological effect of barley root excretions was studied during a 4 to 10 days cultivation period. The effect of root excretions changes according to the cultivation period of barley. It was ascertained by means of a bioassay that growth was either conclusively stimulated or the root excretions did not affect growth of the roots and of the upper part ofNasturtium. No significant inhibitory effect was observed. The effect of the single amino acids and of their mixtures found in the root excretions of barley was quite different. The following amino acids were determined by paper chromatography in root excretions: alanine, asparagine, phenylalanine, glycine, leucine, lysine, serine, tyrosine, glutamic acid and valine plus methionine. During cultivation their total quantity increased from 5·48. 10^?5 up to 1·13. 10^?3 mg per plant. Most of the 20 amino acids observed, displayed in theNasturtium test at a concentration from 0·1 to 1,000 mg/l an inhibitory effect onNasturtium growth. The effect of amino acid mixtures, corresponding qualitatively and quantitatively to the free amino acids in barley root excretions was dependent on their concentration. Growth regulators of the auxin type were found in culture solutions by chromatographic separation and with bioassay. As it may be seen from the results obtained, there are besides amino acids and indole derivatives other non-identified compounds involved in the effect of barley root excretions.     

Metabolic Conversion of Amino Acids Loaded in the Vacuole of Chara australis Internodal Cells

Vacuoles of internodal cells of Chara australis (or Chara corallina) were loaded with a 10 millimolar amount of various amino acids by a perfusion method and incubated under continuous light. After 20 to 24 hours, the cell sap was collected, and free amino acids in it and the rest of the cell (cytoplasm) were analyzed. The only amino acid metabolized completely was alanine. About 40 to 80% of the aspartic acid, glutamine, serine, and glycine were metabolized, whereas less than 30% of the threonine, asparagine, isoasparagine, isoleucine, phenylalanine, γ-aminobutyric acid, lysine, and arginine were metabolized. The figure for glutamic acid fluctuated between 10 and 100%. The main metabolites of alanine were glutamine, glycine and ammonia, which accumulated in the vacuole. Alanine utilization was not affected by l-methionine-d,l-sulfoximine or azaserine, but was strongly inhibited by aminooxyacetate. The cell extract contained enough alanine aminotransferase activity to account for the rate of alanine metabolism.     

Analysis of stimulatory and inhibitory amino acids for development of hamster one-cell embryos in vitro

Hamster embryo development to the blastocyst stage in vitro can be modulated by amino acids. This series of experiments employed both empirically and statistically designed approaches to elucidate which of 20 amino acids inhibit or stimulate development and to devise a complement of amino acids that best supports in vitro development of hamster 1-cell embryos. Development and/or mean cell number were significantly inhibited by the presence of leucine, tyrosine, valine, isoleucine, phenylalanine, arginine, methionine, or cysteine (at 0.5 mM) and isoleucine, phenylalanine, or tryptophan (at 0.05 mM). Three amino acids—glutamine, taurine, and glycine—were stimulatory and in combination improved development; the culture medium containing these amino acids was designated Hamster Embryo Culture Medium-5. Moreover, addition of another eight amino acids—asparagine, aspartic acid, serine, glutamic acid, histidine, lysine, proline and cysteine (medium designated HECM-6)—had a significant stimulatory effect on development over previously formulated culture media for hamster embryos. These results demonstrated that amino acids, alone and in combination, can markedly stimulate or inhibit hamster embryo development in vitro up to the blastocyst stage. Embryo transfer experiments showed that HECM-5 and ?6 (chemically defined, protein-free culture media) supported normal preimplantation embryo development in vitro. This study also indicates that empirically designed embryo culture media formulations can be as effective as those obtained by application of statistical methodologies. © 1995 wiley-Liss, Inc.     

人乳中氨基酸的含量及分析方法研究进展

人乳中含有丰富的氨基酸,其中赖氨酸、苏氨酸、亮氨酸、缬氨酸、异亮氨酸、苯丙氨酸、甲硫氨酸和组氨酸等必需氨基酸构成比例合理,牛磺酸和谷氨酸等条件必需氨基酸含量丰富,丙氨酸、丝氨酸、天冬氨酸和甘氨酸等非必需氨基酸含量也较为丰富;人乳中含有的氨基酸在维持婴儿生长发育、增强免疫力、肠道保护等方面发挥重要作用.本文综述了人乳中主要氨基酸的含量及分析方法,以期为婴儿食品的开发及母乳成分数据库的建立提供一定的依据.     

Acides aminés de microsporidies parasites de crustacés décapodes marins

The amino acids of four species of Microsporidia parasitizing crustaceans were investigated: three species — Thelohania maenadis, Ormieresia carcini and Ameson pulvis — are parasites of Carcinus mediterraneus; Inodosporus sp. is a parasite of Palaemon serratus. Seventeen protein amino acids were identified of which aspartic acid, glutamic acid and lysine were quantitatively the most important, being quantitatively similar in all four parasites. The relative amounts of the next most abundant amino acids were found to vary and might serve as a systematic criterion at the genus level. For example, phenylalanine is predominant in Ormieresia and leucine in Inodosporus: serine in Thelohania and glycine in Ameson are also predominant, but to a lesser extent. The free amino acids composition shows little qualitative variation among the four genera, but quantitative differences are found in the composition of Microsporidia parasitizing the same host species; this may reflect variations in the amino acid metabolism of the parasite. The urea cycle in Ormeresia is most remarkable in this connection. The free amino acid level in the parasites was generally found to be in inverse proportion to the level in the host; the amino acids which are found to exist at high levels in the parasites correspond to essential amino acids of the Crustacea. Metabolic and adaptative relations are discussed.     

Studies on Amino Acid Sequence Determination from N-Terminal of Peptide by Methylthiohydantoin

Methylisothiocyanate reacts with the amino group of amino acid in alkaline solution to give methylthiocarbamyl amino acid. This is converted to the methylthiohydantoin derivative (MTH-amino acid) by subsequent acidification.

Gas chromatographical identification of 20 amino acids were examined by making MTH-amino acids. Among them, ten amino acids (glycine, alanine, valine, leucine, isoleucine, proline, methionine, phenylalanine, serine and threonine) were successfully identified. Aspartic acid and glutamic acid could be identified as the methyl esters of the MTH-amino acids.     

Effect of sound and Lenzites-decayed wood on the amino acid composition of Reticulitermes flavipes

In hydrolysates of the eastern subterranean termite, Reticulitermes flavipes, the most abundant protein amino acids (μmoles) were glycine, alanine, and glutamic acid; the least abundant were methionine and histidine. Sawdust from both sound and Lenzites trabea-decayed sapwood blocks of sugar maple, loblolly pine, and slash pine was force-fed to termites. A diet of decayed rather than sound wood had little effect on protein amino acid composition of the termites; glycine content varied the most. In contrast, diet affected the free amino acid composition. Except for glutamic acid, the major protein amino acids of the termites were not the predominant free amino acids. Tyrosine and histidine were relatively more abundant as free than as protein amino acids. Greatest differences in protein amino acid compositions of sound and decayed wood were in contents of glycine, leucine, lysine, and arginine.     

Specificity of Amino Acid Transport in Trypanosoma equiperdum*

Uptake of [¹⁴C] alanine, arginine, glutamic acid and phenylalanine by Trypanosoma equiperdum occurred by both a mediated mechanism and diffusion. Twenty amino acids were studied as inhibitors of absorption of the above amino acids. Results suggested that at least 4 distinct transport loci are involved in amino acid transport. These 4 loci have overlapping affinities for amino acids and seem to be involved, respectively, in the absorption of (a) arginine and phenylalanine; (b) arginine; (c) alanine, phenylalanine, and glutamic acid; (d) glutamic acid. The data also showed that multiple sites for substrate binding occur on each of 2 transport systems.     

INCREASED CONCENTRATIONS OF GLYCINE IN HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE-DEFICIENT MOUSE NEUROBLASTOMA CELLS1

—The intracellular concentrations of a number of amino acids were compared in a parental line of mouse neuroblastoma cells, a line selected for gross deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and in a revertant line containing the enzyme selected from the deficient line. Most prominent was the increased concentration of free glycine and to a lesser extent glutamic acid in enzyme-deficient cells. The increase in glycine was eliminated after restoration of the HGPRT activity.     

Characterization of a meta-Fluorotyrosine-Tolerant Cell Culture of Eschscholtzia californica Cham

A cell line of Eschscholtzia californica selected for meta-fluorotyrosine (MFT) tolerance was found to have 10-fold increased levels of phenylalanine and tyrosine compared to the parent line, while most other amino acids were only increased 2-fold. Tracer experiments with shikimic acid in the presence of MFT showed that the biosynthesis of the aromatic amino acids was not impaired in the tolerant line. Feeding experiments with phenylalanine, tyrosine, or shikimic acid also revealed a reduced turnover of the pools of the aromatic amino acids in the variant. Thus undisturbed de novo biosynthesis of the aromatic amino acids and dilution of toxic effects of MFT by the enlarged pool sizes seemed to be the main reason for the acquired tolerance. Despite the enlarged availability of the precursor tyrosine, formation of the benzophenanthridine alkaloids was enhanced neither in the growth nor in the production medium.     

Amino Acids from Heterodera glycines

Amino acids emitted and extracted from surface-sterilized larvae and adults of Heterodera glycines were identified by paper chromatography and quantitatively analyzed by column chromatography. Five amino acids (alanine, aspartic acid, glutamic acid, glycine and serine) were emitted by H. glycines larvae and eight others (asparagine, glutamine, leucine/isoleucine, lysine, methionine sulfoxide, threonine, tyrosine, valine/methionine) were found in extracts from crushed larvae.In addition to the amino acids emitted or extracted from larvae, four others were emitted by adults (γ-aminobutyric acid, histidine, phenylalanine, and proline). Four different amino acids (arginine, cystathionine, hydroxyproline, and ornithine) were found only in the extract from crushed adults. Greater quantities of alanine, aspartic acid and glycine were emitted than could be detected in nematode extracts suggesting selective emission.Subsamples of nematode populations were taken from growing plants 19, 26, 33, and 40 days after inoculation and extracted to determine whether changes in specific amino acid content correlated with aging. Proline content shifted most, increasing from 4.1% to 21.5% of the total amino acid complement from the 19th to the 40th days.     

Amino acid utilization by L-M strain mouse cells in a chemically defined medium

Summary The amino acid requirements of strain L-M mouse cells grown in a chemically defined medium (2×Eagle) containing only the 13 essential amino acids (EAA) were investigated. Medium and acid hydrolysate samples were analyzed for amino acid content by the method of ion exchange chromatography. The extent of utilization of the EAA differed;e.g. after 120 hr of cell growth without medium change, glutamine was exhausted from the medium; methionine, leucine, isoleucine, cystine, arginine, and valine were depleted 60 to 80%; other EAA were used to lesser extents. Although the EAA were used in excess of their requirements for protein synthesis, a correlation could generally be made between utilization and protein amino acid composition. Glutamine appeared to be, a growth-limiting factor. Use of U-¹⁴C-labeled glutamine indicated that over one-half of the metabolized glutamine was converted to carbon dioxide, 17% to cell material, and 15% was extracted from the amino acid pools. Nonessential amino acids (NEAA), viz. alanine, aspartic acid, glutamic acid, glycine, proline, and serine, were released into the medium during growth, and some were reutilized. Exogenous provision of these did not improve cell growth. In contrast to the other NEAA, only serine showed net utilization when provided exogenously. When glutamic acid largely replaced the glutamine in the medium, it exerted a sparing effect on the glutamine requirement for protein synthesis. Suggestions are given for the improvement of Eagle medium for cell growth. Supported by Research Grants CA 03720 and CA 11802 from the National Institutes of Health. Predoctoral, fellow supported, by Grant F01-GM-42156-02 from the National Institutes of Health.     

Amino acid requirements for growth of the rabbit blastocyst in vitro

Ten amino acids, namely, arginine, histidine, lysine, tryptophane, methionine, phenylalanine, leucine, valine, threonine and serine were indispensable for growth of rabbit blastocysts in vitro; others were nonessential. Of all the essential amino acids, arginine and lysine were required in relatively high concentrations, 10^?2 M and 10^?3 M, respectively, for optimum growth. Complete omission of the non-essential amino acids from the medium markedly reduced blastocyst growth. Interaction between serine and glycine demonstrated a partial sparing action on serine by glycine, similar to that observed between methionine and cysteine. The amino acid composition of a culture medium capable of providing continuous and consistent growth of rabbit blastocysts in vitro is described.     

Variation in amino acid composition of cytochrome c of species in the fungal genusUstilago

Cytochrome c was extracted and purified from nine species of the genusUstilago, representing five pathogen for monocotyledonous and four for dicotyledonous host species. The amino acid compositions of acid hydrolysates of cytochrome c from these species were compared and divergence values were calculated for all pairs of species. Aspartic acid, serine, glutamic acid, proline, glycine, alanine, valine, leucine, phenylalanine, lysine, and arginine were the most variable amino acids for both dicot and monocot pathogens. Differences in lysine, glutamic acid, alanine, and histidine distinguished most monocot and dicot pathogens. The dicotyledonous pathogens had fewer glutamic acid and additional alanine and histidine residues. Divergence values for cytochrome c were generally highest between species of dicotyledonous and monocotyledonous hosts and lowest for species within the monocotyledonous group. Pairs of species in the dicotyledonous group gave values only slightly lower than those for pairs with species from different groups.