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Sample records for amino acid accumulation

  1. Accumulated analyses of amino acid precursors in returned lunar samples

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Harada, K.; Hare, P. E.

    1973-01-01

    Six amino acids (glycine, alanine, aspartic acid, glutamic acid, serine, and threonine) obtained by hydrolysis of extracts have been quantitatively determined in ten collections of fines from five Apollo missions. Although the amounts found, 7-45 ng/g, are small, the lunar amino acid/carbon ratios are comparable to those of the carbonaceous chondrites, Murchison and Murray, as analyzed by the same procedures. Since both the ratios of amino acid to carbon, and the four or five most common types of proteinous amino acid found, are comparable for the two extraterrestrial sources despite different cosmophysical histories of the moon and meteorites, common cosmochemical processes are suggested.

  2. Gamma amino butyric acid accumulation in medicinal plants without stress

    PubMed Central

    Anju, P.; Moothedath, Ismail; Rema Shree, Azhimala Bhaskaranpillai

    2014-01-01

    Introduction: Gamma amino butyric acid (GABA) is an important ubiquitous four carbon nonprotein amino acid with an amino group attached to gamma carbon instead of beta carbon. It exists in different organisms including bacteria, plants, and animals and plays a crucial role in humans by regulating neuronal excitability throughout the nervous system. It is directly responsible for the regulation of muscle tone and also effective in lowering stress, blood pressure, and hypertension. Aim and Objective: The aim of the study was to develop the fingerprint profile of selected medicinally and economically important plants having central nervous system (CNS) activity and to determine the quantity of GABA in the selected plants grown under natural conditions without any added stress. Materials and Methods: The high-performance thin layer chromatography analysis was performed on precoated silica gel plate 60F–254 plate (20 cm × 10 cm) in the form of bands with width 8 mm using Hamilton syringe (100 μl) using n-butanol, acetic acid, and water in the proportion 5:2:2 as mobile phase in a CAMAG chamber which was previously saturated for 30 min. CAMAG TLC scanner 3 was used for the densitometric scanning at 550 nm. Specific marker compounds were used for the quantification. Results and Conclusion: Among the screened medicinal plants, Zingiber officinale and Solanum torvum were found to have GABA. The percentage of GABA present in Z. officinale and S. torvum were found to be 0.0114% and 0.0119%, respectively. The present work confirmed that among the selected CNS active medicinal plants, only two plants contain GABA. We found a negative correlation with plant having CNS activity and accumulation of GABA. The GABA shunt is a conserved pathway in eukaryotes and prokaryotes but, although the role of GABA as a neurotransmitter in mammals is clearly established, its role in plants is still vague. PMID:25861139

  3. Magnesium nutrition on accumulation and transport of amino acids in tea plants.

    PubMed

    Ruan, Jianyun; Ma, Lifeng; Yang, Yajun

    2012-05-01

    Free amino acids in young tea shoots are important chemical constituents, remarkably influencing the quality of green teas. Nutrient solution, soil pot and field experiments were conducted to investigate the effect of magnesium nutritional status on accumulation and transport of free amino acids in tea plants (Camellia sinensis (L.) O. Kuntze). A sufficient supply of Mg in nutrient solution increased biomass production and concentrations of free amino acids, notably theanine in young shoots and roots, without affecting total N in the leaves, absorption rates of inorganic N and glutamine synthetase activity. Amino acids in xylem saps and phloem exudates or total sugars in phloem exudates of tea plants from pot and field experiments showed their highest levels in bud breaking and shoot extension in early spring (March and early April). Application of Mg increased the amounts of amino acids and total sugars in the xylem saps and phloem exudates. Adequate supply of Mg nutrient promoted the synthesis of theanine in roots and its accumulation in the young shoots of tea plants. Magnesium nutritional status was an important factor influencing the mobility of amino acids and sugars via xylem and phloem especially when N and C reserves remobilized to support spring growth of young shoots. Copyright © 2011 Society of Chemical Industry.

  4. [Accumulation of amino acid substitutions promotes irreversible structural changes in the hemagglutinin of human influenza AH3 virus during evolution].

    PubMed

    Nakajima, Katsuhisa; Nobusawa, Eri; Nakajima, Setsuko

    2006-06-01

    During protein evolution the amino acid substitutions accumulate with time. However, the effect of accumulation of the amino acid substitutions to structural changes has not been estimated well. We will propose that the discordance of amino acid substitution on the HA protein of influenza A virus is useful for the assessment of structural changes during evolution. Discordance value can be obtained from the experimental data of tolerance or intolerance by introducing site directed mutagenesis at the homologous positions of two HA proteins holding the same amino acid residues. The value of discordance correlated to the number of amino acid differences among proteins. In the H3HA discordance rate was calculated to be 0.45% per one amino acid change. Furthermore, discordance of amino acid substitutions suggests that tolerable amino acid substitutions in different order have a probability of promoting irreversible divergence of the HA protein to different subtypes.

  5. Different Accumulation of Free Amino Acids during Short- and Long-Term Osmotic Stress in Wheat

    PubMed Central

    Kovács, Zita; Simon-Sarkadi, Livia; Vashegyi, Ildikó; Kocsy, Gábor

    2012-01-01

    The effect of wheat chromosome 5A on free amino acid accumulation induced by osmotic stress was compared in chromosome 5A substitution lines with different freezing tolerance. Treatment with 15% polyethylene glycol (PEG) resulted in greater total free amino acid content even after 3 days compared to the controls. The ratio of amino acids belonging to various amino acid families differed after 3-week treatment in the control and PEG-treated plants only in the case of the freezing-sensitive substitution line. There was a transient increase with a maximum after 3 days in the amounts of several amino acids, after which their concentrations exhibited a more gradual increase. During the first days of osmotic stress the Glu, Gln, Asp, Asn, Thr, Ser, Leu, and His concentrations were greater in the tolerant substitution line than in the sensitive one, while the opposite relationship was observed at the end of the PEG treatment. The coordinated changes in the levels of individual amino acids indicated that they are involved in both the short- and long-term responses to osmotic stress. The alterations differed in the two chromosome 5A substitution lines, depending on the stress tolerance of the chromosome donor genotype. PMID:22919298

  6. Effects of simple rain-shelter cultivation on fatty acid and amino acid accumulation in 'Chardonnay' grape berries.

    PubMed

    Meng, Nan; Ren, Zhi-Yuan; Yang, Xiao-Fan; Pan, Qiu-Hong

    2017-07-29

    Fatty acids and amino acids are the precursors of aliphatic and aromatic volatile compounds, higher alcohols and esters. They are also nutrition for yeast metabolism during fermentation. However, few reports have been concerned about the effect of viticulture practices on the accumulation of fatty acids and amino acids in wine grapes. This study aimed to explore the accumulation of these compounds in developing Vitis vinifera L. cv. Chardonnay grape berries under two vintages, and compare the influences of the rain-shelter cultivation and open-field cultivation. Fifteen fatty acids and 21 amino acids were detected in total. The rain-shelter cultivation led to an increase in the total concentration of fatty acids, and a decrease in the total concentration of amino acids compared with the open-field cultivation in 2012, while no significant difference was observed between two cultivation modes in 2013 vintage. Concentrations of palmitoleic acid, isoleucine and cysteine were significantly promoted in the rain-shelter grape berries, whereas those of tyrosine and ornithine were markedly reduced in both vintages. The rain-shelter cultivation of wine grapes in the rainy region is beneficial for improving grape quality and fermentation activity by influence on the concentration of fatty acids and amino acids. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Accumulation of seleno-amino acids in legume and grass plant species grown in selenium-laden soils

    SciTech Connect

    Wu, L.; Guo, X.; Banuelos, G.S.

    1997-03-01

    Seleno-amino acid accumulation was studied for two legume and two grass species grown in Selenium (Se)-laden soils. An antagonistic relationship was found between the tissue Se-amino acid concentration and the corresponding sulfur-amino acid concentration. This relationship demonstrates a competitive interaction between Se and sulfate at the amino acid synthesis level. The nonsulfur-containing amino acids were not substantially affected by the increase of tissue Se concentration. Sour clover (Melilotus indica L.) was able to accumulate much greater tissue Se concentration than the other three species. Tissue methionine concentration of sour clover, rabbitfoot grass (Polypogon monspeliensis L.), and tall fescue (Festuca arundinacea Schreb.) was not significantly affected by the increase of tissue selenomethionine concentration, but a highly significant negative correlation was found in alfalfa (Medicago sativa L.). This discrepancy suggests that a less antagonistic effect on sulfur-amino acids under the increase of Se-amino acid analogues in the tissue might be able to minimize Se toxicity to the plant. Both Se-methylselenocysteine (nonprotein amino acid) and selenomethionine (protein amino acid) accumulated in the plants when grown in Se-laden soils. Possible effects of these Se-amino acids accumulated by plants on animal health should be tested before the plants are used for forage supplementation.

  8. Osmotic Stress-Induced Polyamine Accumulation in Cereal Leaves : II. Relation to Amino Acid Pools.

    PubMed

    Flores, H E; Galston, A W

    1984-05-01

    Arginine decarboxylase activity increases 2- to 3-fold in osmotically stressed oat leaves in both light and dark, but putrescine accumulation in the dark is only one-third to one-half of that in light-stressed leaves. If arginine or ornithine are supplied to dark-stressed leaves, putrescine rises to levels comparable to those obtained by incubation under light. Thus, precursor amino acid availability is limiting to the stress response. Amino acid levels change rapidly upon osmotic treatment; notably, glutamic acid decreases with a corresponding rise in glutamine. Difluoromethylarginine (0.01-0.1 millimolar), the enzyme-activated irreversible inhibitor of arginine decarboxylase, prevents the stress-induced putrescine rise, as well as the incorporation of label from [(14)C]arginine, with the expected accumulation of free arginine, but has no effect on the rest of the amino acid pool. The use of specific inhibitors such as alpha-difluoromethylarginine is suggested as probes for the physiological significance of stress responses by plant cells.

  9. Amino acids

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

  10. Proteolysis of chloroplast proteins is responsible for accumulation of free amino acids in dark-treated tea (Camellia sinensis) leaves.

    PubMed

    Chen, Yiyong; Fu, Xiumin; Mei, Xin; Zhou, Ying; Cheng, Sihua; Zeng, Lanting; Dong, Fang; Yang, Ziyin

    2017-03-22

    Shade management (dark treatment) on tea (Camellia sinensis) plants is a common approach to improve free amino acids in raw materials of tea leaves. However, the reason for amino acid accumulation in dark-treated tea leaves is still unknown. In the present study, dark treatment significantly increased content of free amino acids and reduced content of soluble proteins in tea leaves. Quantitative proteomics analysis showed that most enzymes involved in biosyntheses of amino acids were down-accumulated by dark treatment. Chloroplast numbers reduced in dark-treated leaves and the content of soluble proteins reduced in the chloroplasts isolated from dark-treated leaves compared to control. These suggest that proteolysis of chloroplast proteins contributed to amino acid accumulation in dark-treated leaves. Two chloroplasts proteases, ATP-dependent Clp protease proteolytic subunit 3 and protease Do-like 2, were up-accumulated in dark-treated leaves. This study firstly elucidated the mechanism of accumulation of amino acids in dark-treated tea leaves. Effect of dark on crop growth has been widely studied, while less attention has been paid to effect of dark on quality-related metabolites in crops. Shade management (dark treatment) on tea plants is a common approach to improve free amino acids in tea leaves. However, the reason for accumulation of free amino acids in dark-treated tea leaves is still unknown. In the present study, an iTRAQ-based quantitative proteomic analysis was performed and the results revealed the accumulation of free amino acids in dark-treated tea leaves was not due to activation of biosyntheses of amino acids, but resulted from proteolysis of chloroplast proteins. The information will advance our understanding of formation of quality or function-related metabolites in agricultural crops exposed to dark stress/shade management. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Transgenic manipulation of a single polyamine in poplar cells affects the accumulation of all amino acids

    Treesearch

    Sridev Mohapatra; Rakesh Minocha; Stephanie Long; Subhash C. Minocha

    2010-01-01

    The polyamine metabolic pathway is intricately connected to metabolism of several amino acids. While ornithine and arginine are direct precursors of putrescine, they themselves are synthesized from glutamate in multiple steps involving several enzymes. Additionally, glutamate is an amino group donor for several other amino acids and acts as a substrate for biosynthesis...

  12. Arsenate and arsenite exposure modulate antioxidants and amino acids in contrasting arsenic accumulating rice (Oryza sativa L.) genotypes.

    PubMed

    Dave, Richa; Tripathi, Rudra Deo; Dwivedi, Sanjay; Tripathi, Preeti; Dixit, Garima; Sharma, Yogesh Kumar; Trivedi, Prabodh Kumar; Corpas, Francisco J; Barroso, Juan B; Chakrabarty, Debasis

    2013-11-15

    Carcinogenic arsenic (As) concentrations are found in rice due to irrigation with contaminated groundwater in South-East Asia. The present study evaluates comparative antioxidant property and specific amino acid accumulation in contrasting rice genotypes corresponding to differential As accumulation during arsenate (As(V)) and arsenite (As(III)) exposures. The study was conducted on two contrasting As accumulating rice genotypes selected from 303 genotype accessions, in hydroponic conditions. Maximum As accumulation was up to 1181 μg g(-1) dw in the roots of high As accumulating genotype (HARG), and 89 μg g(-1) dw in low As accumulating genotype (LARG) under As(III) exposures. The inorganic As was correlated more significantly upon exposures to As(III) than As(V). In the presence of As(V) various antioxidant enzymes guiacol peroxidase (GPX), ascorbate peroxidase (APX) and superoxide dismutase (SOD) were highly stimulated in HARG. The stress responsive amino acids proline, cysteine, glycine, glutamic acid and methionine showed higher accumulation in HARG than LARG. A clear correlation was found between stress responsive amino acids, As accumulation and antioxidative response. The comparisons between the contrasting genotypes helped to determine the significance of antioxidants and specific amino acid response to As stress.

  13. Aberrant detergent-insoluble excitatory amino acid transporter 2 accumulates in Alzheimer disease.

    PubMed

    Woltjer, Randall L; Duerson, Kevin; Fullmer, Joseph M; Mookherjee, Paramita; Ryan, Allison M; Montine, Thomas J; Kaye, Jeffrey A; Quinn, Joseph F; Silbert, Lisa; Erten-Lyons, Deniz; Leverenz, James B; Bird, Thomas D; Pow, David V; Tanaka, Kohichi; Watson, G Stennis; Cook, David G

    2010-07-01

    Alzheimer disease (AD) is characterized by deposition of amyloid-beta, tau, and other specific proteins that accumulate in the brain in detergent-insoluble complexes. Alzheimer disease also involves glutamatergic neurotransmitter system disturbances. Excitatory amino acid transporter 2 (EAAT2) is the dominant glutamate transporter in cerebral cortex and hippocampus. We investigated whether accumulation of detergent-insoluble EAAT2 is related to cognitive impairment and neuropathologic changes in AD by quantifying detergent-insoluble EAAT2 levels in hippocampus and frontal cortex of cognitively normal patients, patients with clinical dementia rating of 0.5 (mildly impaired), and AD patients. Parkinson disease patients served as neurodegenerative disease controls. We found that Triton X-100-insoluble EAAT2 levels were significantly increased in patients with AD compared with controls, whereas Triton X-100-insoluble EAAT2 levels inpatients with clinical dementia rating of 0.5 were intermediately elevated between control and AD subjects. Detergent insolubility of presenilin-1, a structurally similar protein, did not differ among the groups, thus arguing that EAAT2 detergent insolubility was not caused by nonspecific cellular injury. These findings demonstrate that detergent-insoluble EAAT2 accumulation is a progressive biochemical lesion that correlates with cognitive impairment and neuropathologic changes in AD. These findings lend further support to the idea that dysregulation of the glutamatergic system may play a significant role in AD pathogenesis.

  14. Accumulation of amino acids by the perfused rat liver in the presence of ethanol

    PubMed Central

    Krebs, Hans A.; Hems, Reginald; Lund, Patricia

    1973-01-01

    1. The rate of gluconeogenesis from alanine in the perfused rat liver is affected by the presence of other metabolizable substances, especially fatty acids, ornithine and ethanol. Gluconeogenesis is accelerated by oleate and by ornithine. When both oleate and ornithine were present the acceleration was greater than expected on the basis of mere additive effects. 2. Much NH3 and some urea were formed from alanine when no ornithine was added. With ornithine almost all the nitrogen released from alanine appeared as urea. 3. Lactate was a major product of alanine metabolism. Addition of oleate, and especially of oleate plus ornithine, decreased lactate formation. 4. Ethanol had no major effect on gluconeogenesis from alanine when this was the sole added precursor. Gluconeogenesis was strongly inhibited (87%) when oleate was also added, but ethanol greatly accelerated gluconeogenesis when ornithine was added together with alanine. 5. In the absence of ethanol the alanine carbon and alanine nitrogen removed were essentially recovered in the form of glucose, lactate, pyruvate, NH3 and urea. 6. In the presence of ethanol the balance of both alanine carbon and alanine nitrogen showed substantial deficits. These deficits were largely accounted for by the formation of aspartate and glutamine, the formation of which was increased two- to three-fold. 7. When alanine was replaced by lactate plus NH4Cl, ethanol also caused a major accumulation of amino acids, especially of aspartate and alanine. 8. Earlier apparently discrepant results on the effects of ethanol on gluconeogenesis from alanine are explained by the fact that under well defined conditions ethanol can inhibit, or accelerate, or be without major effect on the rate of gluconeogenesis. 9. It is pointed out that in the synthesis of urea through the ornithine cycle half of the nitrogen must be supplied in the form of asparate and half in the form of carbamoyl phosphate. The accumulation of aspartate and other amino acids

  15. Comparative proteomics of Rhizopus delemar ATCC 20344 unravels the role of amino acid catabolism in fumarate accumulation

    PubMed Central

    Sloothaak, Jasper; van Heck, Ruben G.A.; Martins dos Santos, Vitor A.P.; Suarez-Diez, Maria

    2017-01-01

    The filamentous fungus Rhizopus delemar naturally accumulates relatively high amounts of fumarate. Although the culture conditions that increase fumarate yields are well established, the network underlying the accumulation of fumarate is not yet fully understood. We set out to increase the knowledge about fumarate accumulation in R. delemar. To this end, we combined a transcriptomics and proteomics approach to identify key metabolic pathways involved in fumarate production in R. delemar, and propose that a substantial part of the fumarate accumulated in R. delemar during nitrogen starvation results from the urea cycle due to amino acid catabolism. PMID:28382234

  16. Amino acid accumulation in frog muscle. II. Are cycloleucine fluxes consistent with an adsorption model for concentrative uptake of amino acid?

    PubMed

    Neville, M C

    1975-03-25

    Cycloleucine accumulation by frog muscle was studied at 0 degrees C and 25 degrees C. At external concentrations less than 5 mM the distribution ratio of cycloleucine is higher at 0 degrees C. At concentrations greater than 5 mM the converse is true due to apparent exclusion of cycloleucine from a larger portion of the cell water at 0 degrees C than at 25 degrees C. The steady state data are consistent with an adsorption model for amino acid accumulation. Flux studies provide a means to rule out this model if all the possible rate-limiting steps in the movement of amino acid into and out of the cell are considered. These steps include intra-cytoplasmic diffusion, desorption from cytoplasmic or membrane sites and passage through the cell membrane. The assumption is made that the rate-limiting step for influx and efflux is the same, allowing the use of either influx or efflux data to examine the model. Diffusion-limited flux is ruled out on the basis of "influx profile analysis" of the time course of cycloleucine entry at both 0 degrees C and 25 degrees C. At least 95% of all intracellular cycloleucine leaves frog muscle cells with a single exponential time course at both 0 degrees C and 25 degrees C. The rate constant of efflux does not vary with cellular concentration. These findings are shown to be incompatible with desorption-limited efflux. They are compatible with membrane-limited efflux only if (i) adsorption sites are located on membranes with direct access to the extracellular space and (ii) the rate constant for desorption is equal to the rate constant of membrane-limited efflux of free amino acid. It is considered unlikely that such a coincidence would occur at both 0 degrees C and 25 degrees C. Therefore, an adsorption model for cycloleucine accumulation in frog muscle appears to be untenable.

  17. Accumulation of free amino acids in marine diatom resting cells during rejuvenation

    NASA Astrophysics Data System (ADS)

    Chen, Changping; Li, Qingyu; Zhou, Qianqian; Sun, Lin; Zheng, Minhua; Gao, Yahui

    2014-01-01

    Many diatoms form resting stages under adverse growth conditions. These resting stages are known to rejuvenate once favorable conditions return, and resume vegetative growth after a certain lag period in which no divisions occurred, but what happens during this period remains unclear. Nitrogen uptake and the accumulation of free amino acids in Skeletonema marinoi resting cells during rejuvenation, but before cell division, were studied in laboratory cultures at different light intensities using the 15N-tracer technique. N uptake rate was higher for the rejuvenating cells at the higher light intensity. We hypothesized that the rapid and increasing N uptake at higher irradiance could enable S. marinoi to rebuild and reorganize its cell contents quickly and so dominate subsequent vegetative growth on the surficial sediment. Compared to the logarithmic growth phase and stationary phase, much higher concentrations of glycine (Gly) and histidine (His) were detected in resting cells, and His appeared to be a storage compound in S. marinoi resting cells. Compared to glutamine, glutamate had the higher 15N label enrichment under the light condition, showing a diel variation of N status during the lag period. The 15N labeled urea was detected at 36 h, compared to the urea cycle intermediates ornithine and citrulline at 30 h, indicating that urea was produced as an N reservoir due to the higher nitrogen uptake in the dark, and that the urea cycle was involved in S. marinoi resting cell rejuvenation.

  18. Accumulation of free amino acids during exposure to drought in three springtail species.

    PubMed

    Holmstrup, Martin; Slotsbo, Stine; Rozsypal, Jan; Henriksen, Per G; Bayley, Mark

    2015-11-01

    Springtails are closely related to insects, but they differ from these with respect to water balance, in particular because springtails are small and have high integumental permeability to water. Here we report a series of experiments addressing the dynamics of osmoregulation, water content and accumulation of free amino acids (FAAs) in three springtail species during exposure to a gradually increasing environmental desiccation simulating conditions in drought exposed soil. Folsomia candida and Protaphorura fimata (both living in the deeper soil layers; euedaphic species) were active throughout the 3week exposure, with the developing drought regime ending at -3.56MPa (the soil water activity at the permanent wilting point of plants is -1.5MPa) and remained hyperosmotic (having an body fluid osmolality higher than the corresponding environment) to their surrounding air. Sinella curviseta (living in upper soil/litter layers; hemiedaphic species) also survived this exposure, but remained hypoosmotic throughout (i.e. with lower osmolality than the environment). The body content of most FAAs increased in response to drought in all three species. Alanine, proline and arginine were the most significantly upregulated FAAs. By combining our results with data in the literature, we could account for 82% of the observed osmolality at -3.56MPa in F. candida and 92% in P. fimata. The osmolality of S. curviseta was only slightly increased under drought, but here FAAs were considerably more important as osmolytes than in the two other species. We propose that FAAs probably have general importance in drought tolerance of springtails.

  19. Accumulation of amino acid substitutions promotes irreversible structural changes in the hemagglutinin of human influenza AH3 virus during evolution.

    PubMed

    Nakajima, Katsuhisa; Nobusawa, Eri; Nagy, Alexander; Nakajima, Setsuko

    2005-05-01

    In order to clarify the effect of an accumulation of amino acid substitutions on the hemadsorption character of the influenza AH3 virus hemagglutinin (HA) protein, we introduced single-point amino acid changes into the HA1 domain of the HA proteins of influenza viruses isolated in 1968 (A/Aichi/2/68) and 1997 (A/Sydney/5/97) by using PCR-based random mutation or site-directed mutagenesis. These substitutions were classified as positive or negative according to their effects on the hemadsorption activity. The rate of positive substitutions was about 50% for both strains. Of 44 amino acid changes that were identical in the two strains with regard to both the substituted amino acids and their positions in the HA1 domain, 22% of the changes that were positive in A/Aichi/2/68 were negative in A/Sydney/5/97 and 27% of the changes that were negative in A/Aichi/2/68 were positive in A/Sydney/5/97. A similar discordance rate was also seen for the antigenic sites. These results suggest that the accumulation of amino acid substitutions in the HA protein during evolution promoted irreversible structural changes and therefore that antigenic changes in the H3HA protein may not be limited.

  20. Prey-induced changes in the accumulation of amino acids and phenolic metabolites in the leaves of Drosera capensis L.

    PubMed

    Kováčik, Jozef; Klejdus, Bořivoj; Stork, František; Hedbavny, Josef

    2012-04-01

    Effect of prey feeding (ants Formica fusca) on the quantitative changes in the accumulation of free amino acids, soluble proteins, phenolic metabolites and mineral nutrients in the leaves of carnivorous plant Drosera capensis was studied. Arginine was the most abundant compound in Drosera leaves, while proline was abundant in ants. The amount of the majority of amino acids and their sum were elevated in the fed leaves after 3 and 21 days, and the same, but with further enhancement after 21 days, was observed in ants. Accumulation of amino acids also increased in young non-fed leaves of fed plants. Soluble proteins decreased in ants, but were not enhanced in fed leaves. This confirms the effectiveness of sundew's enzymatic machinery in digestion of prey and suggests that amino acids are not in situ deposited, but rather are allocated within the plant. The content of total soluble phenols, flavonoids and two selected flavonols (quercetin and kaempferol) was not affected by feeding in Drosera leaves, indicating that their high basal level was sufficient for the plant's metabolism and prey-induced changes were mainly N based. The prey also showed to be an important source of other nutrients besides N, and a stimulation of root uptake of some mineral nutrients is assumed (Mg, Cu, Zn). Accumulation of Ca and Na was not affected by feeding.

  1. Effect of salinity on seed germination, accumulation of proline and free amino acid in Pennisetum glaucum (L.) R. Br.

    PubMed

    Sneha, Sonam; Rishi, Anirudha; Dadhich, Amit; Chandra, Subhash

    2013-09-01

    Salinity is a major threat to agriculture, plants exhibits a variety of responses to salt stress that enable them to tolerate and survive in such conditions. Salinity affects physiological and biochemical processes in plants. A short term salt stress induced physiological and biochemical response were observed in P. glaucum. The experiment was conducted to understand the influence of salinity on seed germination, proline and free amino acid accumulation in P. glaucum. It was observed that as the salt concentration increased the germination percentage decreased as compared to control as well as the root/shoot length also decreased. This suggests that salinity greatly influences the germination as well as the plant growth. The levels ofbiochemical components proline and free amino acid were measured during the salt stressed condition. The 14 days old seedlings were subjected to 4 salt treatments (50, 100, 150 and 200 mM NaCI), free proline and free amino acids was calculated at 0, 12, 24, 48, 72 and 96th hour. Proline and free amino acid content in the salt stressed tissues increased with increase in salt concentration as well as with duration of salt stress. This result suggests that proline and free amino acid acids acts as compatible solutes in P. glaucum to protect the cellular macromolecules, maintain the osmotic balance and also scavenge the free radicals under salt stressed condition.

  2. Effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids in the juice sacs of Satsuma mandarin (Citrus unshiu Marc.) fruit.

    PubMed

    Matsumoto, Hikaru; Ikoma, Yoshinori

    2012-10-03

    To elucidate the effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids and to determine the best temperature to minimize their postharvest change, their content after harvest was investigated at 5, 10, 20, and 30 °C for 14 days in the juice sacs of Satsuma mandarin (Citrus unshiu Marc. cv. Aoshima-unshiu) fruit. In all sugars, the changes were negligible at all temperatures. Organic acids decreased slightly at all temperatures, with the exception of malic acid at 30 °C, which increased slightly. Two amino acids, ornithine and glutamine, increased at 5 °C, but they did not increase at other temperatures. In 11 amino acids (phenylalanine, tryptophan, tyrosine, isoleucine, leucine, valine, threonine, lysine, methionine, histidine, and γ-amino butyric acid), the content was higher at 20 and 30 °C than at other temperatures. Thus, the content of amino acids was more variable than that of sugars and organic acids in response to temperatures. Moreover, amino acids responded to temperature differently: two amino acids were cold responsive, and 11 were heat-responsive. The best temperature to minimize the postharvest changes in amino acid profiles in the juice sacs of Aoshima-unshiu was 10 °C. The responsiveness to temperatures in two cold-responsive (ornithine and glutamine) and five heat-responsive (phenylalanine, tryptophan, valine, lysine, and histidine) amino acids was conserved among three different Satsuma mandarin cultivars, Aoshima-unshiu (late-maturing cultivar), Silverhill (midmaturing cultivar), and Miyagawa-wase (early-maturing cultivar). The metabolic responsiveness to temperature stress was discussed on the basis of the changes in the amino acid profile.

  3. Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae).

    PubMed

    Chia, Mathias Ahii; Lombardi, Ana Teresa; da Graça Gama Melão, Maria; Parrish, Christopher C

    2015-03-01

    Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10(-7) and 2.0×10(-8)molL(-1) Cd) under varying nitrogen (2.9×10(-6), 1.1×10(-5) and 1.1×10(-3)molL(-1)N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Accumulation, selection and covariation of amino acids in sieve tube sap of tansy (Tanacetum vulgare) and castor bean (Ricinus communis): evidence for the function of a basic amino acid transporter and the absence of a γ-amino butyric acid transporter.

    PubMed

    Bauer, Susanne N; Nowak, Heike; Keller, Frank; Kallarackal, Jose; Hajirezaei, Mohamad-Reza; Komor, Ewald

    2014-09-01

    Sieve tube sap was obtained from Tanacetum by aphid stylectomy and from Ricinus after apical bud decapitation. The amino acids in sieve tube sap were analyzed and compared with those from leaves. Arginine and lysine accumulated in the sieve tube sap of Tanacetum more than 10-fold compared to the leaf extracts and they were, together with asparagine and serine, preferably selected into the sieve tube sap, whereas glycine, methionine/tryptophan and γ-amino butyric acid were partially or completely excluded. The two basic amino acids also showed a close covariation in sieve tube sap. The acidic amino acids also grouped together, but antagonistic to the other amino acids. The accumulation ratios between sieve tube sap and leaf extracts were smaller in Ricinus than in Tanacetum. Arginine, histidine, lysine and glutamine were enriched and preferentially loaded into the phloem, together with isoleucine and valine. In contrast, glycine and methionine/tryptophan were partially and γ-amino butyric acid almost completely excluded from sieve tube sap. The covariation analysis grouped arginine together with several neutral amino acids. The acidic amino acids were loaded under competition with neutral amino acids. It is concluded from comparison with the substrate specificities of already characterized plant amino acid transporters, that an AtCAT1-like transporter functions in phloem loading of basic amino acids, whereas a transporter like AtGAT1 is absent in phloem. Although Tanacetum and Ricinus have different minor vein architecture, their phloem loading specificities for amino acids are relatively similar.

  5. Foliar amino acid accumulation as an indicator of ecosystem stress for first-year sugar maple seedlings

    SciTech Connect

    McLaughlin, J.W.; Reed, D.D.; Jurgensen, M.F.

    1994-01-01

    Accumulation of certain plant foliar amino acids (arginine, glutamine, and proline) can be used as indicators of anthropogenic and natural stressors, such as atmospheric deposition and mineral nutritional imbalances, which result in decreased plant growth. In this study a number of factors were evaluated to assess the use of foliar amino acid accumulation as indicators of sugar maple seedling stress at two sugar maple dominated forests in Michigan. These factors were: (1) first-year sugar maple (Acer saccharum Marshall) seedling growth, (2) N and P nutrition, (3) soluble foliar and root total amino acid concentrations, and (4) concentrations of foliar arginine, glutamine, and proline. The most southern site (Wellston), which was exposed to high atmospheric deposition and had high available soil P and seedling foliar P, had greater seedling growth. Foliar glutamine, arginine, and proline were greater at the most northern site (Alberta), which received lesser amounts of atmospheric deposition, but also had lower levels of available soil phosphorus, seedling foliar phosphorus, less seedling growth, and greater canopy closure. These results suggest that since atmospheric deposition is high in nitrogen, even the low levels of deposition at Alberta may be interacting with ecological variables such as, available soil phosphorus, light, or moisture to result in NIP imbalances and consequently higher arginine and glutamine concentrations in seedling foliage. 37 refs., 4 figs., 3 tabs.

  6. Metabolism of organic acids, nitrogen and amino acids in chlorotic leaves of 'Honeycrisp' apple (Malus domestica Borkh) with excessive accumulation of carbohydrates.

    PubMed

    Wang, Huicong; Ma, Fangfang; Cheng, Lailiang

    2010-07-01

    Metabolite profiles and activities of key enzymes in the metabolism of organic acids, nitrogen and amino acids were compared between chlorotic leaves and normal leaves of 'Honeycrisp' apple to understand how accumulation of non-structural carbohydrates affects the metabolism of organic acids, nitrogen and amino acids. Excessive accumulation of non-structural carbohydrates and much lower CO(2) assimilation were found in chlorotic leaves than in normal leaves, confirming feedback inhibition of photosynthesis in chlorotic leaves. Dark respiration and activities of several key enzymes in glycolysis and tricarboxylic acid (TCA) cycle, ATP-phosphofructokinase, pyruvate kinase, citrate synthase, aconitase and isocitrate dehydrogenase were significantly higher in chlorotic leaves than in normal leaves. However, concentrations of most organic acids including phosphoenolpyruvate (PEP), pyruvate, oxaloacetate, 2-oxoglutarate, malate and fumarate, and activities of key enzymes involved in the anapleurotic pathway including PEP carboxylase, NAD-malate dehydrogenase and NAD-malic enzyme were significantly lower in chlorotic leaves than in normal leaves. Concentrations of soluble proteins and most free amino acids were significantly lower in chlorotic leaves than in normal leaves. Activities of key enzymes in nitrogen assimilation and amino acid synthesis, including nitrate reductase, glutamine synthetase, ferredoxin and NADH-dependent glutamate synthase, and glutamate pyruvate transaminase were significantly lower in chlorotic leaves than in normal leaves. It was concluded that, in response to excessive accumulation of non-structural carbohydrates, glycolysis and TCA cycle were up-regulated to "consume" the excess carbon available, whereas the anapleurotic pathway, nitrogen assimilation and amino acid synthesis were down-regulated to reduce the overall rate of amino acid and protein synthesis.

  7. 1-FFT amino acids involved in high DP inulin accumulation in Viguiera discolor.

    PubMed

    De Sadeleer, Emerik; Vergauwen, Rudy; Struyf, Tom; Le Roy, Katrien; Van den Ende, Wim

    2015-01-01

    Fructans are important vacuolar reserve carbohydrates with drought, cold, ROS and general abiotic stress mediating properties. They occur in 15% of all flowering plants and are believed to display health benefits as a prebiotic and dietary fiber. Fructans are synthesized by specific fructosyltransferases and classified based on the linkage type between fructosyl units. Inulins, one of these fructan types with β(2-1) linkages, are elongated by fructan:fructan 1-fructosyltransferases (1-FFT) using a fructosyl unit from a donor inulin to elongate the acceptor inulin molecule. The sequence identity of the 1-FFT of Viguiera discolor (Vd) and Helianthus tuberosus (Ht) is 91% although these enzymes produce distinct fructans. The Vd 1-FFT produces high degree of polymerization (DP) inulins by preferring the elongation of long chain inulins, in contrast to the Ht 1-FFT which prefers small molecules (DP3 or 4) as acceptor. Since higher DP inulins have interesting properties for industrial, food and medical applications, we report here on the influence of two amino acids on the high DP inulin production capacity of the Vd 1-FFT. Introducing the M19F and H308T mutations in the active site of the Vd 1-FFT greatly reduces its capacity to produce high DP inulin molecules. Both amino acids can be considered important to this capacity, although the double mutation had a much higher impact than the single mutations.

  8. 1-FFT amino acids involved in high DP inulin accumulation in Viguiera discolor

    PubMed Central

    De Sadeleer, Emerik; Vergauwen, Rudy; Struyf, Tom; Le Roy, Katrien; Van den Ende, Wim

    2015-01-01

    Fructans are important vacuolar reserve carbohydrates with drought, cold, ROS and general abiotic stress mediating properties. They occur in 15% of all flowering plants and are believed to display health benefits as a prebiotic and dietary fiber. Fructans are synthesized by specific fructosyltransferases and classified based on the linkage type between fructosyl units. Inulins, one of these fructan types with β(2-1) linkages, are elongated by fructan:fructan 1-fructosyltransferases (1-FFT) using a fructosyl unit from a donor inulin to elongate the acceptor inulin molecule. The sequence identity of the 1-FFT of Viguiera discolor (Vd) and Helianthus tuberosus (Ht) is 91% although these enzymes produce distinct fructans. The Vd 1-FFT produces high degree of polymerization (DP) inulins by preferring the elongation of long chain inulins, in contrast to the Ht 1-FFT which prefers small molecules (DP3 or 4) as acceptor. Since higher DP inulins have interesting properties for industrial, food and medical applications, we report here on the influence of two amino acids on the high DP inulin production capacity of the Vd 1-FFT. Introducing the M19F and H308T mutations in the active site of the Vd 1-FFT greatly reduces its capacity to produce high DP inulin molecules. Both amino acids can be considered important to this capacity, although the double mutation had a much higher impact than the single mutations. PMID:26322058

  9. Inhibition of brain energy metabolism by the branched-chain amino acids accumulating in maple syrup urine disease.

    PubMed

    Ribeiro, César A; Sgaravatti, Angela M; Rosa, Rafael B; Schuck, Patrícia F; Grando, Vanessa; Schmidt, Anna L; Ferreira, Gustavo C; Perry, Marcos L S; Dutra-Filho, Carlos S; Wajner, Moacir

    2008-01-01

    In the present work we investigated the in vitro effect of the branched-chain amino acids (BCAA) accumulating in maple syrup urine disease (MSUD) on some parameters of energy metabolism in cerebral cortex of rats. 14CO2 production from [1-14C]acetate, [1-5-14C]citrate and [U-14C]glucose, as well as glucose uptake by the brain were evaluated by incubating cortical prisms from 30-day-old rats in the absence (controls) or presence of leucine (Leu), valine (Val) or isoleucine (Ile). All amino acids significantly reduced 14CO2 production by around 20-55%, in contrast to glucose utilization, which was significantly increased by up to 90%. Furthermore, Leu significantly inhibited the activity of the respiratory chain complex IV, whereas Val and Ile markedly inhibited complexes II-III, III and IV by up to 40%. We also observed that trolox (alpha-tocopherol) and creatine totally prevented the inhibitory effects provoked by the BCAA on the respiratory chain complex activities, suggesting that free radicals were involved in these effects. The results indicate that the major metabolites accumulating in MSUD disturb brain aerobic metabolism by compromising the citric acid cycle and the electron flow through the respiratory chain. We presume that these findings may be of relevance to the understanding of the pathophysiology of the neurological dysfunction of MSUD patients.

  10. Arsenic accumulation and tolerance in rootless macrophyte Najas indica are mediated through antioxidants, amino acids and phytochelatins.

    PubMed

    Tripathi, Rudra Deo; Singh, Ragini; Tripathi, Preeti; Dwivedi, Sanjay; Chauhan, Reshu; Adhikari, Bijan; Trivedi, Prabodh Kumar

    2014-12-01

    Arsenic (As) accumulation and tolerance response of a submerged rootless macrophyte Najas indica were evaluated during arsenate (As(V); 10-250 μM) and arsenite (As(III); 1-50 μM) exposure. Higher As accumulation at As(III) exposure and more tolerance upon As(V) exposure resulted in more toxicity during As(III) stress than As(V), which was evident through measurement of growth parameters and oxidative stress related parameters viz., lipid peroxidation (MDA content), electrical conductivity (EC) and hydrogen peroxide (H2O2) levels. Antioxidant enzymes and various amino acids were more prominent during moderate exposure of As(V), suggesting their possible role in As tolerance and detoxification. Various non-enzymatic antioxidant metabolites viz., ascorbic acid (ASC), glutathione (GSH), non-protein thiols (NPTs) and phytochelatins (PCs) biosynthesis involving phytochelatin synthase (PCS) activity increased more significantly during As(III) stress. However, PCs content seems inadequate in response to As accumulation leading to lower PC-SH:As molar ratio and higher As phytotoxicity during As(III) stress. N. indica may prove useful plant species for phytoremediation purpose in moderately As contaminated water bodies due to high As accumulation and tolerance potential. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Accumulation of Amino Acids in Rhizobium sp. Strain WR1001 in Response to Sodium Chloride Salinity

    PubMed Central

    Hua, Sui-Sheng T.; Tsai, Victor Y.; Lichens, Georgia M.; Noma, Amy T.

    1982-01-01

    Rhizobium sp. strain WR1001, isolated from the Sonoran Desert by Eskew and Ting, was found to be able to grow in defined medium containing NaCl up to 500 mM, a concentration approaching that of sea water. Therefore, it is a valuable strain for studying the biochemical basis of salt tolerance. Intracellular free glutamate was found to increase rapidly in response to osmotic stress by NaCl. It accounted for 88% of the amino acid pool when the bacterium was grown in 500 mM NaCl. The role of glutamate dehydrogenase in glutamate biosynthesis was examined in several Rhizobium strains. Both NADH- and NADPH-dependent glutamate dehydrogenase activities in various Rhizobium strains were observed. The range of activity differed considerably depending on the particular strain. KCl (500 mM) did not stimulate glutamate dehydrogenase activity, as reported in a number of bacterial strains by Measures. The low activity of glutamate dehydrogenase in Rhizobium sp. strain WR1001 apparently cannot fulfill a biosynthetic function of glutamate formation in response to medium NaCl concentrations. PMID:16346049

  12. Fatty acid-amino acid conjugates are essential for systemic activation of salicylic acid-induced protein kinase and accumulation of jasmonic acid in Nicotiana attenuata.

    PubMed

    Hettenhausen, Christian; Heinrich, Maria; Baldwin, Ian T; Wu, Jianqiang

    2014-11-28

    Herbivory induces the activation of mitogen-activated protein kinases (MAPKs), the accumulation of jasmonates and defensive metabolites in damaged leaves and in distal undamaged leaves. Previous studies mainly focused on individual responses and a limited number of systemic leaves, and more research is needed for a better understanding of how different plant parts respond to herbivory. In the wild tobacco Nicotiana attenuata, FACs (fatty acid-amino acid conjugates) in Manduca sexta oral secretions (OS) are the major elicitors that induce herbivory-specific signaling but their role in systemic signaling is largely unknown. Here, we show that simulated herbivory (adding M. sexta OS to fresh wounds) dramatically increased SIPK (salicylic acid-induced protein kinase) activity and jasmonic acid (JA) levels in damaged leaves and in certain (but not all) undamaged systemic leaves, whereas wounding alone had no detectable systemic effects; importantly, FACs and wounding are both required for activating these systemic responses. In contrast to the activation of SIPK and elevation of JA in specific systemic leaves, increases in the activity of an important anti-herbivore defense, trypsin proteinase inhibitor (TPI), were observed in all systemic leaves after simulated herbivory, suggesting that systemic TPI induction does not require SIPK activation and JA increases. Leaf ablation experiments demonstrated that within 10 minutes after simulated herbivory, a signal (or signals) was produced and transported out of the treated leaves, and subsequently activated systemic responses. Our results reveal that N. attenuata specifically recognizes herbivore-derived FACs in damaged leaves and rapidly send out a long-distance signal to phylotactically connected leaves to activate MAPK and JA signaling, and we propose that FACs that penetrated into wounds rapidly induce the production of another long-distance signal(s) which travels to all systemic leaves and activates TPI defense.

  13. Sweating treatment enhances citrus fruit disease resistance by inducing the accumulation of amino acids and salicylic acid-induced resistance pathway.

    PubMed

    Yun, Ze; Zhu, Feng; Liu, Ping; Zeng, Yunliu; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2015-04-20

    To clarify the mechanism of fruit disease resistance activated by sweating treatment, 'Guoqing NO.1' Satsuma mandarin (Citrus unshiu Marc.) fruits were treated by sweating, which is a traditional prestorage treatment in China. Subsequently, we performed inoculation and physiological characterization, two-dimensional gel electrophoresis (2-DE) proteomics analysis and metabonomics analysis based on gas chromatography coupled to mass spectrometry (GC-MS) and high-performance liquid chromatography/electrospray ionization-time of flight-mass spectrometry (HPLC-qTOF-MS). The results showed that sweating treatment significantly inhibited pathogen infection without negatively affecting the fruit commercial quality. In addition, sweating treatment rapidly promoted the accumulation of amino acids (such as proline and serine). Meanwhile, hydrogen peroxide (H2 O2 ) and salicylic acid (SA) were significantly accumulated in the sweating-treated fruit. Thereafter, some stress-response proteins and metabolites [such as ascorbate peroxidase (APX), β-1,3-glucanase, vanillic acid and rutin] which can be induced by SA were also significantly increased in the sweating-treated fruit. Taken together, the disease resistance induced by sweating treatment might be attributed to: (1) the induction of the accumulation of amino acids; and (2) the accumulation of SA and subsequent activation of SA-induced resistance pathway, which can induce the stress-response proteins and metabolites that can directly inhibit pathogen development.

  14. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves

    PubMed Central

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-01-01

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress. PMID:26552588

  15. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves.

    PubMed

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-11-10

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress.

  16. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves

    NASA Astrophysics Data System (ADS)

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-11-01

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress.

  17. Amino acid substitutions in the poliovirus maturation cleavage site affect assembly and result in accumulation of provirions.

    PubMed Central

    Ansardi, D C; Morrow, C D

    1995-01-01

    The assembly of infectious poliovirus virions requires a proteolytic cleavage between an asparagine-serine amino acid pair (the maturation cleavage site) in VP0 after encapsidation of the genomic RNA. In this study, we have investigated the effects that mutations in the maturation cleavage site have on P1 polyprotein processing, assembly of subviral intermediates, and encapsidation of the viral genomic RNA. We have made mutations in the maturation cleavage site which change the asparagine-serine amino acid pair to either glutamine-glycine or threonine-serine. The mutations were created by site-directed mutagenesis of P1 cDNAs which were recombined into wild-type vaccinia virus to generate recombinant vaccinia viruses. The P1 polyproteins expressed from the recombinant vaccinia viruses were analyzed for proteolytic processing and assembly defects in cells coinfected with a recombinant vaccinia virus (VV-P3) that expresses the poliovirus 3CD protease. A trans complementation system using a defective poliovirus genome was utilized to assess the capacity of the mutant P1 proteins to encapsidate genomic RNA (D. C. Ansardi, D. C. Porter, and C. D. Morrow, J. Virol. 67:3684-3690, 1993). The mutant P1 proteins containing the glutamine-glycine amino acid pair (VP4-QG) and the threonine-serine pair (VP4-TS) were processed by 3CD provided in trans from VV-P3. The processed capsid proteins VP0, VP3, and VP1 derived from the mutant precursor VP4-QG were unstable and failed to assemble into subviral structures in cells coinfected with VV-P3. However, the capsid proteins derived from VP4-QG did assemble into empty-capsid-like structures in the presence of the defective poliovirus genome. In contrast, the capsid proteins derived from processing of the VP4-TS mutant assembled into subviral intermediates both in the presence and in the absence of the defective genome RNA. By a sedimentation analysis, we determined that the capsid proteins derived from the VP4-TS precursor

  18. Amino Acid Metabolism Disorders

    MedlinePlus

    ... this process. One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup urine disease. Amino acids are "building blocks" that join together to form ...

  19. Trichoderma inoculation augments grain amino acids and mineral nutrients by modulating arsenic speciation and accumulation in chickpea (Cicer arietinum L.).

    PubMed

    Tripathi, Pratibha; Singh, Poonam C; Mishra, Aradhana; Tripathi, Rudra D; Nautiyal, Chandra S

    2015-07-01

    Trichoderma reesei is an industrially important fungi which also imparts stress tolerance and plant growth promotion in various crops. Arsenic (As) contamination of field soils is one of the challenging problems in agriculture, posing potential threats for both human health and the environment. Plants in association with microbes are a liable method to improve metal tolerance and enhance crop productivity. Chickpea (Cicer arietinum L.), is an important grain legume providing cheap source of protein in semi-arid regions including As affected areas. In this study we report the role of T. reesei NBRI 0716 (NBRI 0716) in supporting chickpea growth and improving soil quality in As simulated conditions. NBRI 0716 modulated the As speciation and its availability to improve grain yield and quality (amino acids and mineral content) in chickpea (C. arietinum L.) plants grown in As spiked soil (100 mg As kg(-1) soil). Arsenic accumulation and speciation results indicate that arsenate [As(V)] was the dominant species in chickpea seeds and rhizosphere soil. The Trichoderma reduced total grain inorganic As (Asi) by 66% and enhanced dimethylarsonic acid (DMA) and monomethylarsinic acid (MMA) content of seed and rhizosphere soil. The results indicate a probable role of NBRI 0716 in As methylation as the possible mechanism for maneuvering As stress in chickpea. Analysis of functional diversity using carbon source utilization (Biolog) showed significant difference in diversity and evenness indices among the soil microbial rhizosphere communities. Microbial diversity loss caused by As were prevented in the presence of Trichoderma NBRI 0716. Copyright © 2015. Published by Elsevier Inc.

  20. Proteins and Amino Acids

    USDA-ARS?s Scientific Manuscript database

    Proteins are the most abundant substances in living organisms and cells. All proteins are constructed from the same twenty amino acids that are linked together by covalent bonds. Shorter chains of two or more amino acids can be linked by covalent bonds to form polypeptides. There are twenty amino...

  1. Amino acid analysis

    NASA Technical Reports Server (NTRS)

    Winitz, M.; Graff, J. (Inventor)

    1974-01-01

    The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

  2. Parenteral Nutrition: Amino Acids.

    PubMed

    Hoffer, Leonard John

    2017-03-10

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness.

  3. Parenteral Nutrition: Amino Acids

    PubMed Central

    Hoffer, Leonard John

    2017-01-01

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness. PMID:28287411

  4. Preclinical characterization of 5-amino-4-oxo-[6-11C]hexanoic acid as an imaging probe to estimate protoporphyrin IX accumulation induced by exogenous aminolevulinic acid.

    PubMed

    Suzuki, Chie; Tsuji, Atsushi B; Kato, Koichi; Kikuchi, Tatsuya; Sudo, Hitomi; Okada, Maki; Sugyo, Aya; Zhang, Ming-Rong; Arano, Yasushi; Saga, Tsuneo

    2014-10-01

    Preoperative noninvasive imaging to estimate the quantity and spatial distribution of protoporphyrin IX (PpIX) accumulation in tumors induced by 5-aminolevulinic acid (ALA) administration is expected to improve the efficacy of ALA-based fluorescence-guided resection and photo- and sonodynamic therapies. PpIX synthesis from exogenous ALA has been reported to be regulated by ALA influx or ALA dehydratase (ALAD) activity, which catalyzes the first step of the synthesis. In this study, we characterized the properties of a (11)C-labeled ALA analog, 5-amino-4-oxo-[6-(11)C]hexanoic acid ((11)C-MALA), as a PET tracer to estimate PpIX accumulation. In vitro uptake of (11)C-MALA and (3)H-ALA was determined in 5 tumor cell lines after 10-min incubation with each tracer at 37°C. The expression levels of ALAD were determined by Western blot analysis. In vivo distribution and dynamic PET studies were conducted in tumor-bearing mice. In vitro and in vivo accumulation of ALA-induced PpIX was determined by measuring fluorescence in extracts of cells or tumors. In vitro uptake of (11)C-MALA in 5 tumor cell lines was correlated with ALAD expression levels and PpIX accumulation. In vivo biodistribution and dynamic PET studies showed that (11)C-MALA was rapidly incorporated into tumors, and the tumor-to-muscle ratio of (11)C-MALA at 1 min after injection was significantly correlated with that of (3)H-ALA. (11)C-MALA in tumors was continuously decreased thereafter, and the elimination rate of (11)C-MALA from AsPC-1 tumors with the highest ALAD expression level was slower than from other tumors with lower expression levels. These results suggest that the influx and intracellular retention of (11)C-MALA reflect ALA influx and ALAD expression levels, respectively. Tumor accumulation of (11)C-MALA at 60 min after injection was strongly correlated with PpIX accumulation in tumor tissues. (11)C-MALA PET has the potential to noninvasively estimate the quantitative and spatial accumulation of

  5. Accumulation of a Threonine Biosynthetic Intermediate Attenuates General Amino Acid Control by Accelerating Degradation of Gcn4 via Pho85 and Cdk8

    PubMed Central

    Rawal, Yashpal; Qiu, Hongfang; Hinnebusch, Alan G.

    2014-01-01

    Gcn4 is a master transcriptional regulator of amino acid and vitamin biosynthetic enzymes subject to the general amino acid control (GAAC), whose expression is upregulated in response to amino acid starvation in Saccharomyces cerevisiae. We found that accumulation of the threonine pathway intermediate β-aspartate semialdehyde (ASA), substrate of homoserine dehydrogenase (Hom6), attenuates the GAAC transcriptional response by accelerating degradation of Gcn4, already an exceedingly unstable protein, in cells starved for isoleucine and valine. The reduction in Gcn4 abundance on ASA accumulation requires Cdk8/Srb10 and Pho85, cyclin-dependent kinases (CDKs) known to mediate rapid turnover of Gcn4 by the proteasome via phosphorylation of the Gcn4 activation domain under nonstarvation conditions. Interestingly, rescue of Gcn4 abundance in hom6 cells by elimination of SRB10 is not accompanied by recovery of transcriptional activation, while equivalent rescue of UAS-bound Gcn4 in hom6 pho85 cells restores greater than wild-type activation of Gcn4 target genes. These and other findings suggest that the two CDKs target different populations of Gcn4 on ASA accumulation, with Srb10 clearing mostly inactive Gcn4 molecules at the promoter that are enriched for sumoylation of the activation domain, and Pho85 clearing molecules unbound to the UAS that include both fully functional and inactive Gcn4 species. PMID:25079372

  6. Evolution of the capsid protein genes of foot-and-mouth disease virus: antigenic variation without accumulation of amino acid substitutions over six decades.

    PubMed Central

    Martínez, M A; Dopazo, J; Hernández, J; Mateu, M G; Sobrino, F; Domingo, E; Knowles, N J

    1992-01-01

    The genetic diversification of foot-and-mouth disease virus (FMDV) of serotype C over a 6-decade period was studied by comparing nucleotide sequences of the capsid protein-coding regions of viruses isolated in Europe, South America, and The Philippines. Phylogenetic trees were derived for VP1 and P1 (VP1, VP2, VP3, and VP4) RNAs by using the least-squares method. Confidence intervals of the derived phylogeny (significance levels of nodes and standard deviations of branch lengths) were placed by application of the bootstrap resampling method. These procedures defined six highly significant major evolutionary lineages and a complex network of sublines for the isolates from South America. In contrast, European isolates are considerably more homogeneous, probably because of the vaccine origin of several of them. The phylogenetic analysis suggests that FMDV CGC Ger/26 (one of the earliest FMDV isolates available) belonged to an evolutionary line which is now apparently extinct. Attempts to date the origin (ancestor) of the FMDVs analyzed met with considerable uncertainty, mainly owing to the stasis noted in European viruses. Remarkably, the evolution of the capsid genes of FMDV was essentially associated with linear accumulation of silent mutations but continuous accumulation of amino acid substitutions was not observed. Thus, the antigenic variation attained by FMDV type C over 6 decades was due to fluctuations among limited combinations of amino acid residues without net accumulation of amino acid replacements over time. PMID:1316467

  7. Amino Acid Crossword Puzzle

    ERIC Educational Resources Information Center

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  8. Amino Acid Crossword Puzzle

    ERIC Educational Resources Information Center

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  9. Recombinant growth hormone enhances muscle myosin heavy-chain mRNA accumulation and amino acid accrual in humans.

    PubMed

    Fong, Y; Rosenbaum, M; Tracey, K J; Raman, G; Hesse, D G; Matthews, D E; Leibel, R L; Gertner, J M; Fischman, D A; Lowry, S F

    1989-05-01

    A potentially lethal complication of trauma, malignancy, and infection is a progressive erosion of muscle protein mass that is not readily reversed by nutritional support. Growth hormone is capable of improving total body nitrogen balance, but its role in myofibrillar protein synthesis in humans is unknown. The acute, in situ muscle protein response to an infusion of methionyl human growth hormone was investigated in the limbs of nutritionally depleted subjects during a period of intravenous refeeding. A 6-hr methionyl growth hormone infusion achieved steady-state serum levels comparable to normal physiologic peaks and was associated with a significant increase in limb amino acid uptake, without a change in body amino acid oxidation. Myosin heavy-chain mRNA levels, measured by quantitative dot blot hybridization, were also significantly elevated after growth hormone administration. The data indicate that methionyl growth hormone can induce intracellular amino acid accrual and increased levels of myofibrillar protein mRNA during hospitalized nutritional support and suggest growth hormone to be a potential therapy of lean body wasting.

  10. Mutations in the Hyperosmotic Stress-Responsive Mitochondrial BASIC AMINO ACID CARRIER2 Enhance Proline Accumulation in Arabidopsis1[C][W

    PubMed Central

    Toka, Iman; Planchais, Séverine; Cabassa, Cécile; Justin, Anne-Marie; De Vos, Delphine; Richard, Luc; Savouré, Arnould; Carol, Pierre

    2010-01-01

    Mitochondrial carrier family proteins are diverse in their substrate specificity, organellar location, and gene expression. In Arabidopsis (Arabidopsis thaliana), 58 genes encode these six-transmembrane-domain proteins. We investigated the biological role of the basic amino acid carrier Basic Amino Acid Carrier2 (BAC2) from Arabidopsis that is structurally and functionally similar to ARG11, a yeast ornithine and arginine carrier, and to Arabidopsis BAC1. By studying the expression of BAC2 and the consequences of its mutation in Arabidopsis, we showed that BAC2 is a genuine mitochondrial protein and that Arabidopsis requires expression of the BAC2 gene in order to use arginine. The BAC2 gene is induced by hyperosmotic stress (with either 0.2 m NaCl or 0.4 m mannitol) and dark-induced senescence. The BAC2 promoter contains numerous stress-related cis-regulatory elements, and the transcriptional activity of BAC2:β-glucuronidase is up-regulated by stress and senescence. Under hyperosmotic stress, bac2 mutants express the P5CS1 proline biosynthetic gene more strongly than the wild type, and this correlates with a greater accumulation of Pro. Our data suggest that BAC2 is a hyperosmotic stress-inducible transporter of basic amino acids that contributes to proline accumulation in response to hyperosmotic stress in Arabidopsis. PMID:20172963

  11. Amino Acids and Chirality

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  12. Accumulation of PrLeg, a Perilla legumin protein in potato tuber results in enhanced level of sulphur-containing amino acids.

    PubMed

    Goo, Young-Min; Kim, Tae-Won; Lee, Min-Kyung; Lee, Shin-Woo

    2013-09-01

    Potato is the fourth staple food in the world, following rice, wheat, and maize, whereas tubers contain high quality of starch, relatively high amounts of vitamin C and many other important substances. It also contains relatively good quality of protein (about 3 to 6% of the dried weight) and patatin, and 11S globulin is a major storage protein with high level of lysine. However, tuber protein contains relatively low amounts of sulphur-containing amino acids, which may result in low nutritional value. Recently, we cloned a gene encoding PrLeg polypeptide, a seed storage protein from Perilla, which contains relatively higher levels of sulphur-containing amino acids. We transformed PrLeg cDNA into a potato plant to over-express under the direction of the tuber-specific promoter, patatin. Most of the transgenic lines identified through PCR and RT-PCR analyses were able to accumulate high amount of prLeg transcript in their tuber tissue, while very little or no transcript that were detected in their leaf tissues. The level of methionine content was elevated up to three-fold compared to non-transgenic parental line, without any significant changes in other amino acids, suggesting that further research is required to get a deeper insight into their nutritional value. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  13. Effect of light quality on the accumulation of photosynthetic pigments, proteins and mycosporine-like amino acids in the red alga Porphyra leucosticta (Bangiales, Rhodophyta).

    PubMed

    Korbee, Nathalie; Figueroa, Félix L; Aguilera, José

    2005-08-01

    The effect of different light qualities (white, blue, green, yellow and red light) on photosynthesis, measured as chlorophyll fluorescence, and the accumulation of photosynthetic pigments, proteins and the UV-absorbing mycosporine-like amino acids (MAAs) was studied in the red alga Porphyra leucosticta. Blue light promoted the highest accumulation of nitrogen metabolism derived compounds i.e., MAAs, phycoerythrin and proteins in previously N-starved algae after seven days culture in ammonium enriched medium. Similar results were observed in the culture under white light. In contrast, the lowest photosynthetic capacity i.e., lowest electron transport rate and lowest photosynthetic efficiency as well as the growth rate were found under blue light, while higher values were found in red and white lights. Blue light favored the accumulation of the MAAs porphyra-334, palythine and asterina-330 in P. leucosticta. However, white, green, yellow and red lights favored the accumulation of shinorine. The increase of porphyra-334, palythine and asterina-330 occurred in blue light simultaneous to a decrease in shinorine. The accumulation of MAAs and other nitrogenous compounds in P. leucosticta under blue light could not be attributed to photosynthesis and the action of a non-photosynthetic blue light photoreceptor is suggested. A non-photosynthetic photoreceptor could be also involved in the MAAs interconversion pathways in P. leucosticta.

  14. Brain amino acid sensing.

    PubMed

    Tsurugizawa, T; Uneyama, H; Torii, K

    2014-09-01

    The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition. © 2014 John Wiley & Sons Ltd.

  15. Effects of light quality and nutrient availability on accumulation of mycosporine-like amino acids in Gymnodinium catenatum (Dinophycea).

    PubMed

    Vale, Paulo

    2015-02-01

    A Portuguese Gymnodinium catenatum Graham strain was studied for its ultraviolet (UV) photoprotective pigments. This strain presented high absorption in the UVA region, in particular in the near UVA region around 370nm, followed by the far-UVA region around 340nm. Absorption in the near-UVA increased when grown under fluorescent when compared to halogen light. This was even more relevant when grown under nutrient-limiting conditions, which even surpassed absorption in the blue region, closely resembling absorption in natural plankton assemblages reported in the literature. HPLC analysis for mycosporine-like amino acids (MAAs), revealed several UV photoprotective pigments common in other marine microalgae from the northwest Atlantic. Amongst the compounds absorbing in the far-UVA region, three were identified by spectra and retention time characteristics: shinorine, porphyra-334, and mycosporine-glycine. In the near-UVA region, the unknown M-370 was usually the most abundant, followed by palythene. The proportional and absolute cellular concentrations of MAAs absorbing in the near-UVA region increased with fluorescent light when compared to halogen light. Additional experiments with light filtration suggest the set of MAAs absorbing in the near-UVA region seem to be regulated separately from the other set of MAAs absorbing in the far-UVA region, and those from the near-UVA region might be stimulated not only by UV but by blue light also. Nutrient availability affected profile: a shift towards MAAs with low nitrogen:carbon ratio (e.g.: mycosporine-glycine) was observed. As G. catenatum requires extensive UV-photoprotection over the entire UVA range, nitrogen availability might strongly restrict blooming, as MAAs are nitrogen-based. This UV sensitivity might help explaining its pronounced autumnal seasonality, tied to a reduced solar exposure. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Elevated acetyl-CoA by amino acid recycling fuels microalgal neutral lipid accumulation in exponential growth phase for biofuel production.

    PubMed

    Yao, Lina; Shen, Hui; Wang, Nan; Tatlay, Jaspaul; Li, Liang; Tan, Tin Wee; Lee, Yuan Kun

    2017-04-01

    Microalgal neutral lipids [mainly in the form of triacylglycerols (TAGs)], feasible substrates for biofuel, are typically accumulated during the stationary growth phase. To make microalgal biofuels economically competitive with fossil fuels, generating strains that trigger TAG accumulation from the exponential growth phase is a promising biological approach. The regulatory mechanisms to trigger TAG accumulation from the exponential growth phase (TAEP) are important to be uncovered for advancing economic feasibility. Through the inhibition of pyruvate dehydrogenase kinase by sodium dichloroacetate, acetyl-CoA level increased, resulting in TAEP in microalga Dunaliella tertiolecta. We further reported refilling of acetyl-CoA pool through branched-chain amino acid catabolism contributed to an overall sixfold TAEP with marginal compromise (4%) on growth in a TAG-rich D. tertiolecta mutant from targeted screening. Herein, a three-step α loop-integrated metabolic model is introduced to shed lights on the neutral lipid regulatory mechanism. This article provides novel approaches to compress lipid production phase and heightens lipid productivity and photosynthetic carbon capture via enhancing acetyl-CoA level, which would optimize renewable microalgal biofuel to fulfil the demanding fuel market.

  17. Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit.

    PubMed

    Sheng, Ling; Shen, Dandan; Luo, Yi; Sun, Xiaohua; Wang, Jinqiu; Luo, Tao; Zeng, Yunliu; Xu, Juan; Deng, Xiuxin; Cheng, Yunjiang

    2017-02-01

    The loss of organic acids during postharvest storage is one of the major factors that reduces the fruit quality and economic value of citrus. Citrate is the most important organic acid in citrus fruits. Molecular evidence has proved that γ-aminobutyric acid (GABA) shunt plays a key role in citrate metabolism. Here, we investigated the effects of exogenous GABA treatment on citrate metabolism and storage quality of postharvest citrus fruit. The content of citrate was significantly increased, which was primarily attributed to the inhibition of the expression of glutamate decarboxylase (GAD). Amino acids, including glutamate, alanine, serine, aspartate and proline, were also increased. Moreover, GABA treatment decreased the fruit rot rate. The activities of antioxidant enzymes and the content of energy source ATP were affected by the treatment. Our results indicate that GABA treatment is a very effective approach for postharvest quality maintenance and improvement of storage performance in citrus production.

  18. Novel renal amino acid transporters.

    PubMed

    Verrey, François; Ristic, Zorica; Romeo, Elisa; Ramadan, Tamara; Makrides, Victoria; Dave, Mital H; Wagner, Carsten A; Camargo, Simone M R

    2005-01-01

    Reabsorption of amino acids, similar to that of glucose, is a major task of the proximal kidney tubule. Various amino acids are actively transported across the luminal brush border membrane into proximal tubule epithelial cells, most of which by cotransport. An important player is the newly identified cotransporter (symporter) B0AT1 (SLC6A19), which imports a broad range of neutral amino acids together with Na+ across the luminal membrane and which is defective in Hartnup disorder. In contrast, cationic amino acids and cystine are taken up in exchange for recycled neutral amino acids by the heterodimeric cystinuria transporter. The basolateral release of some neutral amino acids into the extracellular space is mediated by unidirectional efflux transporters, analogous to GLUT2, that have not yet been definitively identified. Additionally, cationic amino acids and some other neutral amino acids leave the cell basolaterally via heterodimeric obligatory exchangers.

  19. Effects of water deficit stress, shade, weed competition, and kaolin particle film on selected foliar free amino acid accumulations in cotton, Gossypium hirsutum (L.).

    PubMed

    Showler, Allan T

    2002-03-01

    Leaves of cotton plants, Gossypium hirsutum L., stressed by water deficit, reduced daylight, and weed competition, or treated with a kaolin wettable powder formulation were analyzed for levels of 17 free amino acids (FAAs) using reversed-phase high-performance liquid chromatography. Water deficit stress resulted in heightened free proline levels (49.9-fold, P < 0.001) that were correlated with diffusive resistance (seconds per centimeter). Five other FAAs increased, and the amounts of total free essential (for insect growth and development) amino acids and total FAAs also increased (P < or = 0.05). Cotton grown in 50% shade accumulated significantly more free arginine than control plants. In a small-plot weed competition assay, four FAAs increased and three FAAs decreased in association with weed competition, but because free proline levels were not altered and free arginine levels increased, other stresses aside from water deficit, possibly including shading by tall weeds, appear to have caused the changes. In a small-plot kaolin particle film assay, five FAAs were lower in cotton foliage sprayed weekly with kaolin. Because free proline was unaffected and free arginine was lower, it is possible that kaolin's reflectivity heightened light reception. The responses of free proline and arginine to the treatments used in these assays demonstrate that types and degrees of some stresses to cotton can be characterized by accumulations of certain FAAs. The study also demonstrates how some FAA levels can indicate degrees of cotton stress resulting from weed competition and from kaolin particle film application. Porometry and leaf water potential measurements assisted in corroborating some findings of the study.

  20. Amino acids in Arctic aerosols

    NASA Astrophysics Data System (ADS)

    Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

    2012-11-01

    Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 μm) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

  1. Amino acids in Arctic aerosols

    NASA Astrophysics Data System (ADS)

    Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

    2012-07-01

    Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids to quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 μm) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

  2. Synthesis of amino acids

    DOEpatents

    Davis, J.W. Jr.

    1979-09-21

    A method is described for synthesizing amino acids preceding through novel intermediates of the formulas: R/sub 1/R/sub 2/C(OSOC1)CN, R/sub 1/R/sub 2/C(C1)CN and (R/sub 1/R/sub 2/C(CN)O)/sub 2/SO wherein R/sub 1/ and R/sub 2/ are each selected from hydrogen and monovalent hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  3. Sediment accumulation, stratigraphic order, and the extent of time-averaging in lagoonal sediments: a comparison of 210Pb and 14C/amino acid racemization chronologies

    NASA Astrophysics Data System (ADS)

    Kosnik, Matthew A.; Hua, Quan; Kaufman, Darrell S.; Zawadzki, Atun

    2015-03-01

    Carbon-14 calibrated amino acid racemization (14C/AAR) data and lead-210 (210Pb) data are used to examine sediment accumulation rates, stratigraphic order, and the extent of time-averaging in sediments collected from the One Tree Reef lagoon (southern Great Barrier Reef, Australia). The top meter of lagoonal sediment preserves a stratigraphically ordered deposit spanning the last 600 yrs. Despite different assumptions, the 210Pb and 14C/AAR chronologies are remarkably similar indicating consistency in sedimentary processes across sediment grain sizes spanning more than three orders of magnitude (0.1-10 mm). Estimates of long-term sediment accumulation rates range from 2.2 to 1.2 mm yr-1. Molluscan time-averaging in the taphonomically active zone is 19 yrs, whereas below the depth of final burial (~15 cm), it is ~110 yrs/5 cm layer. While not a high-resolution paleontological record, this reef lagoon sediment is suitable for paleoecological studies spanning the period of Western colonization and development. This sedimentary deposit, and others like it, should be useful, albeit not ideal, for quantifying anthropogenic impacts on coral reef systems.

  4. Amino acids in carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.; Peterson, E.

    1975-01-01

    Studies with the combined gas chromatograph-mass spectrometer were conducted to characterize further the amino acids found in extracts of the Murchison meteorite. With the exception of beta-aminoisobutyric acid, all of the amino acids which were found in previous studies of the Murchison meteorite and the Murray meteorite have been identified. The results obtained lend further support to the hypothesis that amino acids are present in the Murchison meteorite as the result of an extraterrestrial abiotic synthesis.

  5. Stable isotope resolved metabolomics revealed the role of anabolic and catabolic processes in glyphosate-induced amino acid accumulation in Amaranthus palmeri biotypes

    USDA-ARS?s Scientific Manuscript database

    Using stable isotope resolved metabolomics (SIRM), we characterized the role of anabolic (de novo synthesis) vs catabolic (protein catalysis) processes contributing to free amino acid pools in glyphosate susceptible (S) and resistant (R) Amaranthus palmeri biotypes. Following exposure to glyphosate ...

  6. Supplementation with branched-chain amino acids ameliorates hypoalbuminemia, prevents sarcopenia, and reduces fat accumulation in the skeletal muscles of patients with liver cirrhosis.

    PubMed

    Kitajima, Yoichiro; Takahashi, Hirokazu; Akiyama, Takumi; Murayama, Kenichiro; Iwane, Shinji; Kuwashiro, Takuya; Tanaka, Kenichi; Kawazoe, Seiji; Ono, Naofumi; Eguchi, Takahisa; Anzai, Keizo; Eguchi, Yuichiro

    2017-07-24

    Liver cirrhosis induces marked metabolic disorders, protein-energy malnutrition, and sarcopenia. The objective of the study reported here was to investigate the effects of dietary branched-chain amino acids (BCAAs) on systemic glucose metabolism, skeletal muscle, and prognosis of patients with liver cirrhosis. Japanese patients with liver cirrhosis (n = 21) were enrolled into a longitudinal study in which their diets were supplemented with BCAAs. We evaluated glucose metabolism and analyzed the skeletal muscle area index (SAI) and intramuscular adipose tissue content (IMAC) using computed tomography. After 48 weeks of supplementation with BCAAs, there were no changes in glucose metabolism and skeletal muscle findings. In patients with ameliorated hypoalbuminemia, IMAC was significantly decreased and SAI was preserved concomitant with decreasing 90- and 120-min post-challenge plasma glucose levels (P < 0.01 each). In patients without increased albumin levels, IMAC was significantly increased and the SAI was significantly decreased (P < 0.01 each). Liver-related event-free survival rates for 72 months were 63.6% in patients with decreased IMAC and 20.0% in patients with increased IMAC. Amelioration of hypoalbuminemia associated with BCAA supplementation correlated with decreased fat accumulation in skeletal muscle, maintenance of skeletal muscle mass, and improved glucose sensitivity, all factors which may contribute to improving the survival of patients with liver cirrhosis.

  7. Spontaneously Occurring Formation of Intranuclear and Cytoplasmic Inclusions in Renal Proximal Epithelium Due to Accumulation of D-Amino Acid Oxidase in Wistar Hannover Rats.

    PubMed

    Shimoyama, Natsumi; Nakatsuji, Shunji; Andoh, Rie; Yamaguchi, Yuko; Tamura, Kazutoshi; Hoshiya, Toru

    2015-07-01

    Intranuclear and cytoplasmic inclusions in the renal proximal tubular epithelium were observed in nontreated male and female Wistar Hannover rats in a 26-week study (32 weeks of age) and a 104-week study (110 weeks of age). The incidence rates were less than 5% in these two studies. In affected animals, the inclusions were observed in more than 60% of proximal tubular epithelium as various sized (approximately 1-8 μm in diameter) round and eosinophilic materials, but not in distal tubules, Henle's loop, or collecting ducts. Ultrastructurally, inclusions appeared finely granular, homogenous with middle-electron density, and without a limiting membrane. These inclusions were determined to be protein histochemically stained by Azan-Mallory and immunoreactive with an antibody against D-amino acid oxidase (DAO). There was no abnormality in in-life observations or in clinical test values suggestive of renal dysfunction. There were no associated degenerative or inflammatory changes in the kidneys, and no similar inclusions were observed in the other organs. These inclusions are very similar to propiverine hydrochloride (propiverine) and norepinephreine/serotonin reuptake inhibitor-induced inclusions. This is the first report of accumulation of DAO and formation of inclusions occurring spontaneously in rat kidneys. The data are important for toxicological studies using Wistar Hannover rats.

  8. Protein and amino acid nutrition

    USDA-ARS?s Scientific Manuscript database

    Dairy cow protein and amino acid nutrition have a significant role in sustainable dairying. Protein, amino acids, and nitrogen are inextricably linked through effects in the rumen, metabolism of the cow, and environmental nutrient management. Feeding systems have been making progress toward emphasiz...

  9. Hydrothermal synthesis of amino acids

    NASA Astrophysics Data System (ADS)

    Marshall, William L.

    1994-05-01

    This study presents further evidence that amino acids can be synthesized rapidly in hydrothermal solutions from reactants that may have been present in primitive environments. Aqueous NH 4HCO 3 solutions were reacted with C 2H 2, H 2, and O 2 (formed in situ from CaC 2, Ca, and H 2O 2) at 200-275°C over 0.2-2 h periods to synthesize several amino acids and abundant amines. These amino acid and amine producing reactions were not observed to occur below 150°C. Amino acids and amines also were synthesized at 210°C from solutions of NH 4OH, HCHO, NaCN, and H 2. When NH 4OH was replaced by NH 4HCO 3, the syntheses predominantly confirmed the recent results of RENNET et al. (1992). Additionally, amino acids and amines were observed to form by reactions among NH 4OH, HCHO, and H 2 at hydrothermal conditions, essentially confirming the results of FOX and WINDSOR (1970). Inclusion of both carbonate and O 2 in these latter solutions greatly enhanced the production rate of amino acids. The amines synthesized hydrothermally could be significant if they are precursors in the amino acid syntheses either at hydrothermal or later at lower temperatures. These observations provide additional input to the current questions of synthesis, stability, and decomposition of amino acids at hydrothermal conditions, and their possible relevance to the origin of life.

  10. Biosynthesis of natural products containing β-amino acids.

    PubMed

    Kudo, Fumitaka; Miyanaga, Akimasa; Eguchi, Tadashi

    2014-08-01

    Covering: up to January, 2014. We focus here on β-amino acids as components of complex natural products because the presence of β-amino acids produces structural diversity in natural products and provides characteristic architectures beyond those of ordinary α-L-amino acids, thus generating significant and unique biological functions in nature. In this review, we first survey the known bioactive β-amino acid-containing natural products including nonribosomal peptides, macrolactam polyketides, and nucleoside-β-amino acid hybrids. Next, the biosynthetic enzymes that form β-amino acids from α-amino acids and the de novo synthesis of β-amino acids are summarized. Then, the mechanisms of β-amino acid incorporation into natural products are reviewed. Because it is anticipated that the rational swapping of the β-amino acid moieties with various side chains and stereochemistries by biosynthetic engineering should lead to the creation of novel architectures and bioactive compounds, the accumulation of knowledge regarding β-amino acid-containing natural product biosynthetic machinery could have a significant impact in this field. In addition, genome mining of characteristic β-amino acid biosynthetic genes and unique β-amino acid incorporation machinery could lead to the discovery of new β-amino acid-containing natural products.

  11. Amino Acids from a Comet

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  12. Amino Acids from a Comet

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  13. Treatment of Amino Acid Metabolism Disorders

    MedlinePlus

    ... Treatment of amino acid metabolism disorders Treatment of amino acid metabolism disorders E-mail to a friend Please ... this page It's been added to your dashboard . Amino acid metabolism disorders are rare health conditions that affect ...

  14. Sucrose phosphate synthase activity and the co-ordination of carbon partitioning during sucrose and amino acid accumulation in desiccation-tolerant leaf material of the C4 resurrection plant Sporobolus stapfianus during dehydration.

    PubMed

    Whittaker, Anne; Martinelli, Tommaso; Farrant, Jill M; Bochicchio, Adriana; Vazzana, Concetta

    2007-01-01

    Both sucrose and amino acids accumulate in desiccation-tolerant leaf material of the C(4) resurrection plant, Sporobolus stapfianus Gandoger (Poaceae). The present investigation was aimed at examining sucrose phosphate synthase (SPS) activity and various metabolic checkpoints involved in the co-ordination of carbon partitioning between these competing pathways during dehydration. In the initial phase of dehydration, photosynthesis and starch content declined to immeasurable levels, whilst significant increases in hexose sugars, sucrose, and amino acids were associated with concomitant significant increases in SPS and pyruvate kinase (PK) activities, and maximal activity levels of phosphoenolpyruvate carboxylase (PEPCase), NADP-dependent isocitrate dehydrogenase (NADP-ICDH), and NADH-dependent glutamate synthase (NADH-GOGAT). The next phase of dehydration was characterized by changes in metabolism coinciding with net hexose sugar phosphorylation. This phase was characterized by a further significant increase in sucrose accumulation, with increased rates of net sucrose accumulation and maximum rates of SPS activity measured under both saturating and limiting (inhibitory) conditions. SPS protein was also increased. The stronger competitive edge of SPS for carbon entering glycolysis during hexose phosphorylation was also demonstrated by the further decrease in respiration and the simultaneous, significant decline in both PEPCase and PK activities. A decreased anabolic demand for 2-oxoglutarate (2OG), which remained constant, was shown by the co-ordinated decrease in GOGAT. It is proposed that the further increase in amino acids in this phase of dehydration may be in part attributable to the breakdown of insoluble proteins.

  15. Amino acids and cell regulation.

    PubMed Central

    Forster, R. P.; Goldstein, L.

    1979-01-01

    Free amino play an important role in regulating cell volume in fishes. Four tissues/cells (skeletal muscle, RBC, brain, and myocardium) of the little skate, Raja erinacea, were selected for detailed study because of their special importance or unique advantage as experimental models. Three particular amino acids, beta-alanine, taurine, and sarcosine play a predominant role in all four tissues. As in higher vertebrates, amino acid uptake in skate brain, heart, and RBC is mediated via a Na+-dependent process. Amino acids leave the skate brain rapidly in response to a sudden decrease in plasma osmolality and/or to a simultaneous drop in extracellular Na+ concentration. However, although amino acids are important for volume regulation in normal brain cells, they do not appear to be likely candidates for the unidentified "idiogenic" osmolytes in mammalian brain cells. The high concentration of taurine in skate myocardium is of special interest because of the special role of this amino acid in myocardial contractility. Thus, unlike beta-alanine and sarcosine, taurine may play a dual role in regulating both cell volume and contractility of myocardial cells. The isolated skate atrium is well suited for in vitro studies of these two processes. PMID:395764

  16. Amino Acid Transport into Cultured Tobacco Cells

    PubMed Central

    Harrington, H. Michael; Henke, Randolph R.

    1981-01-01

    Lysine transport into suspension-cultured Wisconsin-38 tobacco cells was observed. Uptake was linear (up to 90 minutes) with respect to time and amount of tissue only after 4 to 6 hours preincubation in calcium-containing medium. The observed cellular accumulation of lysine was against a concentration gradient and not due to exchange diffusion. Transport was stimulated by low pH and characterized by a biphasic uptake isotherm with two Km values for lysine. System I (Km ≃ 5 × 10−6 molar; Vmax ≃ 180 nanomoles per gram fresh weight per hour) and system II (Km ≃ 10−4 molar; Vmax ≃ 1900 nanomoles per gram fresh weight per hour) were inhibited by N-ethylmaleimide and a variety of respiratory inhibitors. This inhibition was not due to increased efflux. In antagonism experiments, system I was inhibited most effectively by basic amino acids, followed by the sulfur amino acids. System I was only slightly inhibited by the neutral and aromatic amino acids and was not inhibited by the acidic amino acids aspartic and glutamic acids. Transport by system II was inhibited by all of the tested amino acids (including aspartic and glutamic acids) and analogs; however, this system was not inhibited by d-arginine. Neither system was strongly inhibited by d-lysine or the lysine analog S-2-aminoethyl-l-cysteine. Arginine was shown to be a competitive inhibitor of both systems with values for Ki similar to the respective Km values. These studies suggest the presence of at least two amino acid permeases in W-38 tobacco cells. PMID:16661678

  17. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Amino acids. 172.320 Section 172.320 Food and Drugs... Dietary and Nutritional Additives § 172.320 Amino acids. The food additive amino acids may be safely used... consists of one or more of the following individual amino acids in the free, hydrated or anhydrous form or...

  18. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Amino acids. 172.320 Section 172.320 Food and... Dietary and Nutritional Additives § 172.320 Amino acids. The food additive amino acids may be safely used... consists of one or more of the following individual amino acids in the free, hydrated or anhydrous form or...

  19. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Amino acids. 172.320 Section 172.320 Food and....320 Amino acids. The food additive amino acids may be safely used as nutrients added to foods in... individual amino acids in the free, hydrated, or anhydrous form, or as the hydrochloride, sodium, or...

  20. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Amino acids. 172.320 Section 172.320 Food and... Dietary and Nutritional Additives § 172.320 Amino acids. The food additive amino acids may be safely used... consists of one or more of the following individual amino acids in the free, hydrated or anhydrous form or...

  1. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Amino acids. 172.320 Section 172.320 Food and... Dietary and Nutritional Additives § 172.320 Amino acids. The food additive amino acids may be safely used... consists of one or more of the following individual amino acids in the free, hydrated or anhydrous form or...

  2. Gradually accumulating beneficial mutations to improve the thermostability of N-carbamoyl-D-amino acid amidohydrolase by step-wise evolution.

    PubMed

    Zhang, Dalong; Zhu, Fuyun; Fan, Wenchao; Tao, Rongsheng; Yu, Hong; Yang, Yunliu; Jiang, Weihong; Yang, Sheng

    2011-05-01

    To further enhance repeated batch reactions with immobilized N-carbamoyl-D-amino acid amidohydrolase (DCase), which can be used for the industrial production of D-amino acids, the stability of high soluble mutant DCase-M3 from Ralstonia pickettii CGMCC1596 was improved by step-wise evolution. In our previous report, six thermostability-related sites were identified by error-prone PCR. Based on the above result, an improved mutant B5 (Q12L/Q23L/H248Q/T262A/T263S) was obtained through two rounds of DNA shuffling, showing a 10°C increase in the T (50) (defined as the temperature at which heat treatment for 15 min reduced the initial activity by 50%) compared with the parental enzyme DCase-M3. Furthermore, several thermostability-related sites (Met(31), Asn(93), Gln(207), Asn(242), Glu(266), Thr(271), Ala(273)) on B5 were identified using amino acid consensus approach based on sequence alignment of homologous DCases. These sites were further investigated by iterative saturation mutagenesis (ISM), and a combinational mutant D1 (Q12L/Q23L/Q207E/N242G/H248Q/T262A/T263S/E266D/T271I/A273P) that enhanced the T(50) by about 16°C over DCase-M3 was obtained. Oxidative stability assay showed that the most heat-resisting mutant displayed only a slight increase in resistance to hydrogen peroxide. Comparative characterization showed that D1 not only maintained its characteristic high solubility but also shared similar k(cat) and K(m) values and optimum reaction pHs with the parental enzyme. The significantly improved mutants in the immobilized form are expected to be applied in the industrial production of D-p-hydroxyphenylglycine.

  3. Organic acids, amino acids compositions in the root exudates and Cu-accumulation in castor (Ricinus communis L.) Under Cu stress.

    PubMed

    Huang, Guoyong; Guo, Guangguang; Yao, Shiyuan; Zhang, Na; Hu, Hongqing

    2016-01-01

    Ricinus communis L. is a hyperaccumulation plant newly discovered in an abandoned land of Cu mine in China. A hydroponic experiment was then carried out to determine the root exudates in the Cu-tolerant castor (Ricinus communis L.). Plants were grown in nutrient solution with increasing level of Cu doses (0, 100, 250, 500, and 750 μmol/L Cu) in the form of CuSO4. Cu accumulation in the roots and shoots of castor, and root exudates collected from the castor were measured. The results indicated that the castor had a high Cu accumulation capacity and the Cu concentrations in the shoots and roots of the castor treated with 750 μmol/L Cu were 177.1, 14586.7 mg/kg, respectively. Tartaric was the largest in the root exudates in terms of concentrations, which reached up to 329.13 μmol/g (dry plant) in the level of 750 μmol/L Cu. There was a significantly positive linear relationship between the Cu concentration in root and the concentration of succinic (R = 0.92, P < 0.05), tartaric (R = 0.96, P < 0.01), and citric (R = 0.89, P < 0.05). These results indicated that the difference in root exudation from castor could affect their Cu tolerance. What is more, significant is that the high tartaric and citric, the low oxalic and cysteine in the root exudation of castor contributed to toleration of high Cu concentrations.

  4. Interaction of Adjacent Amino Acids

    NASA Astrophysics Data System (ADS)

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2008-02-01

    Ramachandran plots display the dihedral angles of a single protein residue. We here propose a crossed torsion angle plot called SSY-plot between two neighboring amino acids and demonstrate that a special coherence motion can exist between some very special amino acid pairs leading to spontaneous unusual structures. We also suggest that the existence of two domains corresponds to a bifurcation between two different protein structures and that the special pair is the key to producing these two structures. These are two different structures and are produced spontaneously without an external agent.

  5. Genetic manipulation of proline accumulation influences the concentrations of other amino acids in soybean subjected to simultaneous drought and heat stress.

    PubMed

    Simon-Sarkadi, Livia; Kocsy, Gábor; Várhegyi, Agnes; Galiba, Gábor; de Ronde, Jacoba A

    2005-09-21

    The effect of simultaneous drought and heat stress on free amino acid levels was compared in wild type and transgenic soybean (Glycine max (L.) Merr cv Ibis) plants transformed with the cDNA coding for the last enzyme of Pro biosynthesis, l-Delta(1)-pyrroline-5-carboxylate reductase (EC 1.5.1.2), in sense and antisense directions. The most rapid increase in Pro content was found in the sense transformants that exhibited the least water loss, while the slowest elevation of Pro levels was detected in the antisense transformants that exhibited the greatest water loss during stress. Correspondingly, the level of the Pro precursors Glu and Arg was higher in sense transformants and lower in antisense ones compared to the wild type plants during the initial part of the stress. Interestingly, genetic manipulation of Pro levels also affected the stress-induced changes in the concentration of several other amino acids, which indicates the coordinated regulation of their metabolic pathways.

  6. A single amino acid in the helicase domain of PMMoV-S is responsible for its enhanced accumulation in C. chinense (L(3)L(3)) plants at 32°C.

    PubMed

    Tena, Fátima; Molina-Galdeano, Myriam; Serra, Maria Teresa; García-Luque, Isabel

    2012-05-25

    In Capsicum chinense (L(3)L(3)) plants a higher accumulation of the tobamovirus Pepper mild mottle virus strain S (PMMoV-S) as compared to the Italian strain PMMoV-I is detected when plants are grown at 32°C. By using a reverse genetic approach, we have established that a single amino acid at position 898 in the helicase domain of the polymerase protein, outside of the conserved regions of the helicase, is critical for the higher accumulation of PMMoV-S observed. It also is necessary for both increased accumulation of viral RNA of both polarities in pepper protoplasts and enhanced cell-to-cell movement in C. chinense plants. The influence of thermoresistance of PMMoV-S, a P(1,2) pathotype, and its prevalence on pepper cultivars over PMMoV-I, a P(1,2,3), pathotype, is discussed.

  7. Transport of Aromatic Amino Acids by Pseudomonas aeruginosa

    PubMed Central

    Kay, W. W.; Gronlund, Audrey F.

    1971-01-01

    Kinetic studies of the transport of aromatic amino acids by Pseudomonas aeruginosa revealed the existence of two high-affinity transport systems which recognized the three aromatic amino acids. From competition data and studies on the exchange of preformed aromatic amino acid pools, the first transport system was found to be functional with phenylalanine, tyrosine, and tryptophan (in order of decreasing activity), whereas the second system was active with tryptophan, phenylalanine, and tyrosine. The two systems also transported a number of aromatic amino acid analogues but not other amino acids. Mutants defective in each of the two and in both transport systems were isolated and described. When the amino acids were added at low external concentrations to cells growing logarithmically in glucose minimal medium, the tryptophan pool very quickly became saturated. Under identical conditions, phenylalanine and tyrosine each accumulated in the intracellular pool of P. aeruginosa at a concentration which was 10 times greater than that of tryptophan. PMID:4994029

  8. Role of sialic acid in synaptosomal transport of amino acid transmitters

    SciTech Connect

    Zaleska, M.M.; Erecinska, M.

    1987-03-01

    Active, high-affinity, sodium-dependent uptake of (/sup 14/C)-aminobutyric acid and of the acidic amino acid D-(/sup 3/H)-aspartate was inhibited by pretreatment of synaptosomes with neuraminidase from Vibrio cholerae. Inhibition was of a noncompetitive type and was related to the amount of sialic acid released. The maximum accumulation ratios of both amino acids (intracellular (amino acid)/extracellular (amino acid)) remained largely unaltered. Treatment with neuraminidase affected neither the synaptosomal energy levels nor the concentration of internal potassium. It is suggested that the ..gamma..-aminobutyric acid and acidic amino acid transporters are glycosylated and that sialic acid is involved in the operation of the carrier proteins directly and not through modification of driving forces responsible for amino acid uptake.

  9. Inhibition of D-amino acid oxidase by alpha-keto acids analogs of amino acids.

    PubMed

    Moreno, J A; Montes, F J; Catalán, J; Galán, M A

    1996-04-01

    The inhibition of D-amino acid oxidase by certain alpha-keto acids products of the reaction with D-amino acids, in particular alpha-keto acids that are analogs of the amino acids alanine, valine, leucine, phenylanaline, phenylglycine, tyrosine and tryptophan, is reported. All the alpha-keto acids assayed behaved as substrate competitive inhibitors of the enzyme. The relationship between the degree of inhibition and the structure of the inhibitor is discussed.

  10. Toward Sustainable Amino Acid Production.

    PubMed

    Usuda, Yoshihiro; Hara, Yoshihiko; Kojima, Hiroyuki

    2016-11-22

    Because the global amino acid production industry has been growing steadily and is expected to grow even more in the future, efficient production by fermentation is of great importance from economic and sustainability viewpoints. Many systems biology technologies, such as genome breeding, omics analysis, metabolic flux analysis, and metabolic simulation, have been employed for the improvement of amino acid-producing strains of bacteria. Synthetic biological approaches have recently been applied to strain development. It is also important to use sustainable carbon sources, such as glycerol or pyrolytic sugars from cellulosic biomass, instead of conventional carbon sources, such as glucose or sucrose, which can be used as food. Furthermore, reduction of sub-raw substrates has been shown to lead to reduction of environmental burdens and cost. Recently, a new fermentation system for glutamate production under acidic pH was developed to decrease the amount of one sub-raw material, ammonium, for maintenance of culture pH. At the same time, the utilization of fermentation coproducts, such as cells, ammonium sulfate, and fermentation broth, is a useful approach to decrease waste. In this chapter, further perspectives for future amino acid fermentation from one-carbon compounds are described.

  11. Brain amino acid metabolism and ketosis.

    PubMed

    Yudkoff, M; Daikhin, Y; Nissim, I; Lazarow, A; Nissim, I

    2001-10-15

    The relationship between ketosis and brain amino acid metabolism was studied in mice that consumed a ketogenic diet (>90% of calories as lipid). After 3 days on the diet the blood concentration of 3-OH-butyrate was approximately 5 mmol/l (control = 0.06-0.1 mmol/l). In forebrain and cerebellum the concentration of 3-OH-butyrate was approximately 10-fold higher than control. Brain [citrate] and [lactate] were greater in the ketotic animals. The concentration of whole brain free coenzyme A was lower in ketotic mice. Brain [aspartate] was reduced in forebrain and cerebellum, but [glutamate] and [glutamine] were unchanged. When [(15)N]leucine was administered to follow N metabolism, this labeled amino acid accumulated to a greater extent in the blood and brain of ketotic mice. Total brain aspartate ((14)N + (15)N) was reduced in the ketotic group. The [(15)N]aspartate/[(15)N]glutamate ratio was lower in ketotic animals, consistent with a shift in the equilibrium of the aspartate aminotransferase reaction away from aspartate. Label in [(15)N]GABA and total [(15)N]GABA was increased in ketotic animals. When the ketotic animals were injected with glucose, there was a partial blunting of ketoacidemia within 40 min as well as an increase of brain [aspartate], which was similar to control. When [U-(13)C(6)]glucose was injected, the (13)C label appeared rapidly in brain lactate and in amino acids. Label in brain [U-(13)C(3)]lactate was greater in the ketotic group. The ratio of brain (13)C-amino acid/(13)C-lactate, which reflects the fraction of amino acid carbon that is derived from glucose, was much lower in ketosis, indicating that another carbon source, i.e., ketone bodies, were precursor to aspartate, glutamate, glutamine and GABA.

  12. Nonprotein Amino Acids in the Murchison Meteorite

    PubMed Central

    Kvenvolden, Keith A.; Lawless, James G.; Ponnamperuma, Cyril

    1971-01-01

    Twelve nonprotein amino acids appear to be present in the Murchison meteorite. The identity of eight of them has been conclusively established as N-methylglycine, β-alanine, 2-methylalanine, α-amino-n-butyric acid, β-amino-n-butyric acid, γ-amino-n-butyric acid, isovaline, and pipecolic acid. Tentative evidence is presented for the presence of N-methylalanine, N-ethylglycine, β-aminoisobutyric acid, and norvaline. These amino acids appear to be extraterrestrial in origin and may provide new evidence for the hypothesis of chemical evolution. PMID:16591908

  13. Effect of amino acid intake on brush-border membrane uptake of sulfur amino acids.

    PubMed

    Chesney, R W; Gusowski, N; Padilla, M; Lippincott, S

    1986-07-01

    Alterations in the intake of sulfur amino acids (SAA) changes the rat renal brush-border membrane uptake of the beta-amino acid, taurine. A low-SAA diet enhances and a high-taurine diet reduces uptake (Chesney et al., Kidney Int. 24: 588-594, 1983). Neither the low-SAA diet nor the high-taurine diet alters the time course or concentration-dependent accumulation of the sulfur amino acids methionine and cystine or of inorganic sulfate. By contrast the uptake of beta-alanine, another beta-amino acid that competes with taurine, is greater in animals on the low-SAA diet. The high-taurine diet does not change beta-alanine uptake. The plasma levels of taurine are altered by dietary change, but not the values for methionine and cystine. This study indicates that renal adaptation is expressed for beta-alanine, a nonsulfur-containing beta-amino acid. By contrast, methionine, cystine, and sulfate, which participate in a variety of synthetic and conjugative processes, are not conserved by the renal brush-border surface following ingestion of either a low-methionine and -cystine diet or high-taurine diet.

  14. Analysis of the rice mitochondrial carrier family reveals anaerobic accumulation of a basic amino acid carrier involved in arginine metabolism during seed germination.

    PubMed

    Taylor, Nicolas L; Howell, Katharine A; Heazlewood, Joshua L; Tan, Tzu Yien W; Narsai, Reena; Huang, Shaobai; Whelan, James; Millar, A Harvey

    2010-10-01

    Given the substantial changes in mitochondrial gene expression, the mitochondrial proteome, and respiratory function during rice (Oryza sativa) germination under anaerobic and aerobic conditions, we have attempted to identify changes in mitochondrial membrane transport capacity during these processes. We have assembled a preliminary rice mitochondrial carrier gene family of 50 members, defined its orthology to carriers of known function, and observed significant changes in microarray expression data for these rice genes during germination under aerobic and anaerobic conditions and across rice development. To determine if these transcript changes reflect alteration of the carrier profile itself and to determine which members of the family encode the major mitochondrial carrier proteins, we analyzed mitochondrial integral membrane protein preparations using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and peptide mass spectrometry, identifying seven distinct carrier proteins. We have used mass spectrometry-based quantitative approaches to compare the abundance of these carriers between mitochondria from dry seeds and those from aerobic- or anaerobic-germinated seeds. We highlight an anaerobic-enhanced basic amino acid carrier and show concomitant increases in mitochondrial arginase and the abundance of arginine and ornithine in anaerobic-germinated seeds, consistent with an anaerobic role of this mitochondria carrier. The potential role of this carrier in facilitating mitochondrial involvement in arginine metabolism and the plant urea cycle during the growth of rice coleoptiles and early seed nitrate assimilation under anaerobic conditions are discussed.

  15. Analysis of the Rice Mitochondrial Carrier Family Reveals Anaerobic Accumulation of a Basic Amino Acid Carrier Involved in Arginine Metabolism during Seed Germination1[W][OA

    PubMed Central

    Taylor, Nicolas L.; Howell, Katharine A.; Heazlewood, Joshua L.; Tan, Tzu Yien W.; Narsai, Reena; Huang, Shaobai; Whelan, James; Millar, A. Harvey

    2010-01-01

    Given the substantial changes in mitochondrial gene expression, the mitochondrial proteome, and respiratory function during rice (Oryza sativa) germination under anaerobic and aerobic conditions, we have attempted to identify changes in mitochondrial membrane transport capacity during these processes. We have assembled a preliminary rice mitochondrial carrier gene family of 50 members, defined its orthology to carriers of known function, and observed significant changes in microarray expression data for these rice genes during germination under aerobic and anaerobic conditions and across rice development. To determine if these transcript changes reflect alteration of the carrier profile itself and to determine which members of the family encode the major mitochondrial carrier proteins, we analyzed mitochondrial integral membrane protein preparations using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and peptide mass spectrometry, identifying seven distinct carrier proteins. We have used mass spectrometry-based quantitative approaches to compare the abundance of these carriers between mitochondria from dry seeds and those from aerobic- or anaerobic-germinated seeds. We highlight an anaerobic-enhanced basic amino acid carrier and show concomitant increases in mitochondrial arginase and the abundance of arginine and ornithine in anaerobic-germinated seeds, consistent with an anaerobic role of this mitochondria carrier. The potential role of this carrier in facilitating mitochondrial involvement in arginine metabolism and the plant urea cycle during the growth of rice coleoptiles and early seed nitrate assimilation under anaerobic conditions are discussed. PMID:20720170

  16. Unnatural reactive amino acid genetic code additions

    DOEpatents

    Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.; Anderson, J. Christopher; Schultz, Peter G.

    2014-08-26

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  17. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  18. Amino acids as antioxidants for frying oil

    USDA-ARS?s Scientific Manuscript database

    Amino acids, proteins and hydrolysates of proteins have been known to protect edible oils from oxidation. While amino acids and related materials have high potential as antioxidants for frying oil, effectiveness of each amino acid and mechanisms of their activities are not well understood yet. Propo...

  19. Unnatural reactive amino acid genetic code additions

    SciTech Connect

    Deiters, Alexander; Cropp, Ashton T; Chin, Jason W; Anderson, Christopher J; Schultz, Peter G

    2013-05-21

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  20. Unnatural reactive amino acid genetic code additions

    SciTech Connect

    Deiters, Alexander; Cropp, T Ashton; Chin, Jason W; Anderson, J Christopher; Schultz, Peter G

    2011-02-15

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  1. Unnatural reactive amino acid genetic code additions

    SciTech Connect

    Deiters, Alexander; Cropp, T Ashton; Chin, Jason W; Anderson, J Christopher; Schultz, Peter G

    2011-08-09

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNAsyn-thetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  2. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  3. Amino acid metabolism and protein synthesis in malarial parasites*

    PubMed Central

    Sherman, I. W.

    1977-01-01

    Malaria-infected red cells and free parasites have limited capabilities for the biosynthesis of amino acids. Therefore, the principal amino acid sources for parasite protein synthesis are the plasma free amino acids and host cell haemoglobin. Infected cells and plasmodia incorporate exogenously supplied amino acids into protein. However, the hypothesis that amino acid utilization (from an external source) is related to availability of that amino acid in haemoglobin is without universal support: it is true for isoleucine and for Plasmodium knowlesi and P. falciparum, but not for methionine, cysteine, and other amino acids, and it does not apply to P. lophurae. More by default than by direct evidence, haemoglobin is believed to be the main amino acid reservoir available to the intraerythrocytic plasmodium. Haemoglobin, ingested via the cytostome, is held in food vacuoles where auto-oxidation takes place. As a consequence, haem is released and accumulates in the vacuole as particulate haemozoin (= malaria pigment). Current evidence favours the view that haemozoin is mainly haematin. Acid and alkaline proteases (identified in crude extracts from mammalian and avian malarias) are presumably secreted directly into the food vacuole. They then digest the denatured globin and the resulting amino acids are incorporated into parasite protein. Cell-free protein synthesizing systems have been developed using P. knowlesi and P. lophurae ribosomes. In the main these systems are typically eukaryotic. Studies of amino acid metabolism are exceedingly limited. Arginine, lysine, methionine, and proline are incorporated into protein, whereas glutamic acid is metabolized via an NADP-specific glutamic dehydrogenase. Glutamate oxidation generates NADPH and auxiliary energy (in the form of α-ketoglutarate). The role of red cell glutathione in the economy of the parasite remains obscure. Important goals for future research should be: quantitative assessment of the relative importance of

  4. A mutation in the E2 subunit of the mitochondrial pyruvate dehydrogenase complex in Arabidopsis reduces plant organ size and enhances the accumulation of amino acids and intermediate products of the TCA cycle.

    PubMed

    Yu, Hailan; Du, Xiaoqiu; Zhang, Fengxia; Zhang, Fang; Hu, Yong; Liu, Shichang; Jiang, Xiangning; Wang, Guodong; Liu, Dong

    2012-08-01

    The mitochondrial pyruvate dehydrogenase complex (mtPDC) plays a pivotal role in controlling the entry of carbon into the tricarboxylic acid (TCA) cycle for energy production. This multi-enzyme complex consists of three components: E1, E2, and E3. In Arabidopsis, there are three genes, mtE2-1, mtE2-2, and mtE2-3, which encode the putative mtPDC E2 subunit but how each of them contributes to the total mtPDC activity remains unknown. In this work, we characterized an Arabidopsis mutant, m132, that has abnormal small organs. Molecular cloning indicated that the phenotype of m132 is caused by a mutation in the mtE2-1 gene, which results in a truncation of 109 amino acids at the C-terminus of the encoded protein. In m132, mtPDC activity is only 30% of the WT and ATP production is severely impaired. The mutation in the mtE2-1 gene also leads to the over-accumulation of most intermediate products of the TCA cycle and of all the amino acids for protein synthesis. Our results suggest that, among the three mtE2 genes, mtE2-1 is a major contributor to the function of Arabidopsis mtPDC and that the functional disruption of mtE2-1 profoundly affects plant growth and development, as well as its metabolism.

  5. Amino Acid Properties Conserved in Molecular Evolution

    PubMed Central

    Rudnicki, Witold R.; Mroczek, Teresa; Cudek, Paweł

    2014-01-01

    That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts – one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications. PMID:24967708

  6. Amino acid contents of infant foods.

    PubMed

    Bosch, Lourdes; Alegría, Amparo; Farré, Rosaura

    2006-01-01

    The protein quality of three milk-cereal-based infant foods (paps) was evaluated by determining their amino acid contents and calculating the amino acid score. Proteins were subjected to acid hydrolysis, prior to which cysteine and methionine were oxidized with performic acid. Amino acids were determined by reverse-phase high-performance liquid chromatography with fluorescence detection with a prior derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Tryptophan was determined by reverse-phase high-performance liquid chromatography with ultraviolet detection after basic hydrolysis. Glutamic acid, proline and leucine were the most abundant amino acids, whereas tryptophan and cysteine had the lowest contents. Tryptophan was the limiting amino acid in the analyzed infant foods. A pap serving (250 ml) contributes significantly to fulfillment of the recommended dietary allowances of essential and semi-essential amino acids for infants (7-12 months old) and young children (1-3 years old).

  7. Biological role of D-amino acid oxidase and D-aspartate oxidase. Effects of D-amino acids.

    PubMed

    D'Aniello, A; D'Onofrio, G; Pischetola, M; D'Aniello, G; Vetere, A; Petrucelli, L; Fisher, G H

    1993-12-25

    D-Amino acids administered to animals are absorbed by the intestine and transported through the blood-stream to solid tissues where they are oxidized in vivo by D-amino acid oxidase and D-aspartate oxidase to produce the same compounds they do in vitro; i.e. NH3, H2O2, and the keto acid corresponding to the amino acid ingested. In the liver and kidneys of the animals, an inverse relationship exists between the occurrence of D-amino acids and these oxidative enzymes. For example, younger animals have lower amounts of these oxidases and consequently higher concentrations of free D-amino acids compared to adult animals. If the ingested D-amino acids are not metabolized by these enzymes, they will accumulate in the tissues and may provoke serious damage, e.g. suppression of the synthesis of other essential enzymes and inhibition of the growth rate of the animals. A specific enzyme induction for these D-amino acid oxidases exists in young rats following ingestion of free D-amino acids by the mother. Specifically, when a mother rat ingests D-Ala or D-Asp during pregnancy and suckling, an increase in D-amino acid oxidase or D-aspartate oxidase is observed in the liver and kidneys of the baby rats. These results suggest that the in vivo biological role of these oxidases in animals is to act as detoxifying agents to metabolize D-amino acids which may have accumulated during aging.

  8. Sugar amino acids in designing new molecules.

    PubMed

    Chakraborty, Tushar Kanti; Srinivasu, Pothukanuri; Tapadar, Subhasish; Mohan, Bajjuri Krishna

    2005-03-01

    Emulating the basic principles followed by nature to build its vast repertoire of biomolecules, organic chemists are developing many novel multifunctional building blocks and using them to create 'nature-like' and yet unnatural organic molecules. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. This article describes some of our works on various sugar amino acids and many other related building blocks, like furan amino acids, pyrrole amino acids etc. used in wide-ranging peptidomimetic studies.

  9. Branched-Chain Amino Acids.

    PubMed

    Yamamoto, Keisuke; Tsuchisaka, Atsunari; Yukawa, Hideaki

    Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.

  10. Amino and fatty acids in carbonaceous meteorites

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1974-01-01

    Analyses of two carbonaceous meteorites have provided much of the latest evidence which seems to support Oparin's theory on the origin of life. The meteorites involved are the Murray meteorite, which fell in 1950, and the Murchison meteorite, which fell in 1969. The amino acids in the two meteorites are similar in composition. Eight of the twenty amino acids found belong to amino acids present in proteins. A number of monocarboxylic and dicarboxylic fatty acids were also found in the meteorites.

  11. Amino and fatty acids in carbonaceous meteorites

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1974-01-01

    Analyses of two carbonaceous meteorites have provided much of the latest evidence which seems to support Oparin's theory on the origin of life. The meteorites involved are the Murray meteorite, which fell in 1950, and the Murchison meteorite, which fell in 1969. The amino acids in the two meteorites are similar in composition. Eight of the twenty amino acids found belong to amino acids present in proteins. A number of monocarboxylic and dicarboxylic fatty acids were also found in the meteorites.

  12. THE AMINO ACID COMPOSITION OF CRYSTALLINE PEPSIN

    PubMed Central

    Blumenfeld, Olga O.; Perlmann, Gertrude E.

    1959-01-01

    The amino acid composition of twice recrystallized pepsin (Worthington Biochemical Corporation) has been determined chromatographically on columns of Amberlite IR 120 resin. The results of the analyses obtained on four different preparations indicate a close agreement in their amino acid composition. Pepsin is unique in that it has a great predominance of acidic amino acids over basic ones. Moreover, all the preparations contain a small and constant amount of hydroxyproline, corresponding to about 0.1 residue per molecule. PMID:13620885

  13. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  14. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  15. Amino acid transport by prosthecae of Asticcacaulis biprosthecum: evidence for a broad-range transport system.

    PubMed

    Tam, E; Pate, J L

    1985-10-01

    Prosthecae purified from cells of Asticcaulis biprosthecum possess active transport systems that transport all 20 amino acids tested. Using ascorbate-reduced phenazine methosulphate in the presence of oxygen, all 20 amino acids are accumulated against a concentration gradient by isolated prosthecae. Results of experiments testing the inhibition of transport of one amino acid by another, and of experiments testing the exchange of exogenous amino acids with those preloaded in prosthecae, along with characteristics of mutants defective in amino acid transport, suggest the presence in prosthecae of three amino acid transport systems. One, the general or G system, transports at least 18 of the 20 amino acids tested. Another system, referred to as the proline or P system, transports seven amino acids (including proline) that are also transported by the G system. The third system transports only glutamate and aspartate, and is referred to as the acidic amino acid transport system or A system.

  16. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

    PubMed Central

    Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  17. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

    PubMed

    Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  18. Amino Acid Contents of Meteorite Mineral Separates

    NASA Technical Reports Server (NTRS)

    Berger, E. L.; Burton, A. S; Locke, D.

    2017-01-01

    Indigenous amino acids have been found indigenous all 8 carbonaceous chondrite groups. However, the abundances, structural, enantiomeric and isotopic compositions of amino acids differ significantly among meteorites of different groups and petrologic types. This suggests that parent-body conditions (thermal or aqueous alteration), mineralogy, and the preservation of amino acids are linked. Previously, elucidating specific relationships between amino acids and mineralogy was not possible because the samples analyzed for amino acids were much larger than the scale at which petrologic heterogeneity is observed (sub mm-scale differences corresponding to sub-mg samples). Recent advances in amino acid measurements and application of techniques such as high resolution X-ray diffraction (HR-XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) for mineralogical characterizations allow us to perform coordinated analyses on the scale at which mineral heterogeneity is observed.

  19. Amino Acid Auxotrophy as Immunological Control Nodes

    PubMed Central

    Murray, Peter J.

    2016-01-01

    Summary Cells of the immune system are auxotrophs for most amino acids, including non-essential ones. Arginine and tryptophan are used within the regulatory immune networks to control proliferation and function through pathways that deplete the amino acid, or create regulatory molecules such as nitric oxide or kynurenines. Strategies to harness amino acid auxotrophy to block cancerous lymphocyte growth have been attempted for decades, with limited success. How immune cells integrate information about external essential amino acids supplies and transfer signals to growth and activation pathways remains unclear, but has potential for pathway discovery. Emerging insights may lead to strategies to both degrade amino acids and to block the immunoregulatory pathways controlled by amino acids. PMID:26784254

  20. Indigenous amino acids in primitive CR meteorites

    NASA Astrophysics Data System (ADS)

    Martins, Z.; Alexander, C. M. O. D.; Orzechowska, G. E.; Fogel, M. L.; Ehrenfreund, P.

    CR chondrites are among the most primitive meteorites. In this paper, we report the first measurements of amino acids in Antarctic CR meteorites. Three CRs, Elephant Moraine (EET) 92042, Graves Nunataks (GRA) 95229, and Grosvenor Mountains (GRO) 95577, were analyzed for their amino acid content using high-performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatography-mass spectrometry (GC-MS). Our data show that EET 92042 and GRA 95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations ranging from 180 ppm to 249 ppm. The most abundant amino acids present in the EET 92042 and GRA 95229 meteorites are the α-amino acids glycine, isovaline, α-aminoisobutyric acid (α-AIB), and alanine, with δ13C values ranging from +31.6‰ to +50.5‰. The carbon isotope results together with racemic enantiomeric ratios determined for most amino acids strongly indicate an extraterrestrial origin for these compounds. Compared to Elephant Moraine (EET) 92042 and GRA 95229, the more aqueously altered GRO 95577 is depleted in amino acids. In both CRs and CMs, the absolute amino acid abundances appear to be related to the degree of aqueous alteration in their parent bodies. In addition, the relative abundances of α-AIB and β-alanine in the Antarctic CRs also appear to depend on the degree of aqueous alteration.

  1. Study on the thermal reactions of [60]fullerene with amino acids and amino acid esters.

    PubMed

    Zhu, San-E; Cheng, Xin; Li, Yu-Jin; Mai, Cheng-Kang; Huang, Yong-Shun; Wang, Guan-Wu; Peng, Ru-Fang; Jin, Bo; Chu, Shi-Jin

    2012-11-21

    Thermal reactions of [60]fullerene with a series of amino acids and amino acid esters under aerobic and dark conditions have been investigated. Fulleropyrrolidines can be obtained from these reactions although an aldehyde is not added purposely. Possible reaction mechanisms involving uncommon C-N bond cleavages have been proposed to generate aldehydes, which then react with amino acids and amino acid esters to provide azomethine ylides, followed by 1,3-dipolar cycloaddition to [60]fullerene affording fulleropyrrolidines. Control experiments support our proposed mechanisms, and elucidate the innate nature of C-N bond cleavages of amino acids and amino acid esters.

  2. Amino acids in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Kminek, G.; Botta, O.; Glavin, D. P.; Bada, J. L.

    2002-01-01

    High-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.

  3. Amino acids in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Kminek, G.; Botta, O.; Glavin, D. P.; Bada, J. L.

    2002-01-01

    High-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.

  4. Amino acids precursors in lunar finds

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Harada, K.; Hare, P. E.; Hinsch, G.; Mueller, G.

    1975-01-01

    The consistent pattern is discussed of amino acids found in lunar dust from Apollo missions. The evidence indicates that compounds yielding amino acids were implanted into the surface of the moon by the solar wind, and the kind and amounts of amino acids found on the moon are closely similar to those found in meteorites. It is concluded that there is a common cosmochemical pattern for the moom and meteorites, and this offers evidence of a common course of cosmochemical reactions for carbon.

  5. α-Amino Acid-Isosteric α-Amino Tetrazoles

    PubMed Central

    Zhao, Ting; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; Herdtweck, Eberhardt

    2016-01-01

    The synthesis of all 20 common natural proteinogenic and 4 otherα-amino acid-isosteric α-amino tetrazoles has been accomplished, whereby the carboxyl group is replaced by the isosteric 5-tetrazolyl group. The short process involves the use of the key Ugi tetrazole reaction followed by deprotection chemistries. The tetrazole group is bioisosteric to the carboxylic acid and is widely used in medicinal chemistry and drug design. Surprisingly, several of the common α-amino acid-isosteric α-amino tetrazoles are unknown up to now. Therefore a rapid synthetic access to this compound class and non-natural derivatives is of high interest to advance the field. PMID:26817531

  6. Amino acid composition of some Mexican foods.

    PubMed

    Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor

    2005-06-01

    Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.

  7. The complete amino acid sequence of prochymosin.

    PubMed Central

    Foltmann, B; Pedersen, V B; Jacobsen, H; Kauffman, D; Wybrandt, G

    1977-01-01

    The total sequence of 365 amino acid residues in bovine prochymosin is presented. Alignment with the amino acid sequence of porcine pepsinogen shows that 204 amino acid residues are common to the two zymogens. Further comparison and alignment with the amino acid sequence of penicillopepsin shows that 66 residues are located at identical positions in all three proteases. The three enzymes belong to a large group of proteases with two aspartate residues in the active center. This group forms a family derived from one common ancestor. PMID:329280

  8. Relationship between amino acid usage and amino acid evolution in primates.

    PubMed

    Liu, Haoxuan; Xie, Zhengqing; Tan, Shengjun; Zhang, Xiaohui; Yang, Sihai

    2015-02-25

    Amino acid usage varies from species to species. A previous study has found a universal trend in amino acid gain and loss in many taxa and a one-way model of amino acid evolution in which the number of new amino acids increases as the number of old amino acids decreases was proposed. Later studies showed that this pattern of amino acid gain and loss is likely to be compatible with the neutral theory. The present work aimed to further study this problem by investigating the evolutionary patterns of amino acids in 8 primates (the nucleotide and protein alignments are available online http://gattaca.nju.edu.cn/pub_data.html). First, the number of amino acids gained and lost was calculated and the evolution trend of each amino acid was inferred. These values were found to be closely related to the usage of each amino acid. Then we analyzed the mutational trend of amino acid substitution in human using SNPs, this trend is highly correlated with fixation trend only with greater variance. Finally, the trends in the evolution of 20 amino acids were evaluated in human on different time scales, and the increasing rate of 5 significantly increasing amino acids was found to decrease as a function of time elapsed since divergence, and the dS/dN ratio also found to increase as a function of time elapsed since divergence. These results suggested that the observed amino acid substitution pattern is influenced by mutation and purifying selection. In conclusion, the present study shows that usage of amino acids is an important factor capable of influencing the observed pattern of amino acid evolution, and also presented evidences suggesting that the observed universal trend of amino acid gain and loss is compatible with neutral evolution. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Effect of domoic acid on brain amino acid levels.

    PubMed

    Durán, R; Arufe, M C; Arias, B; Alfonso, M

    1995-03-01

    The administration of Domoic Acid (Dom) in a 0.2 mg/kg i.p. dose induces changes in the levels of amino acids of neurochemical interest (Asp, Glu, Gly, Tau, Ala, GABA) in different rat brain regions (hypothalamus, hippocampus, amygdala, striatum, cortex and midbrain). The most affected amino acid is the GABA, the main inhibitory amino acid neurotransmitter, whereas glutamate, the main excitatory amino acid, is not affected. The rat brain regions that seem to be the main target of the Dom action belong to the limbic system (hippocampus, amygdala). The possible implication of the amino acids in the actions of Dom is also discussed.

  10. Polymerization on the rocks: beta-amino acids and arginine

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have studied the accumulation of long oligomers of beta-amino acids on the surface of minerals using the 'polymerization on the rocks' protocol. We find that long oligopeptides of beta-glutamic acid which cannot be formed in homogeneous aqueous solution are accumulated efficiently on the surface of hydroxylapatite using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as condensing agent. The EDAC-induced oligomerization of aspartic acid on hydroxylapatite proceeds even more efficiently. Hydroxylapatite can also facilitate the ligation of the tripeptide (glu)3. The 'polymerization on the rocks' scenario is not restricted to negatively-charged amino acids. Oligoarginines are accumulated on the surface of illite using carbonyldiimidizole (CDI) as condensing agent. We find that FeS2 catalyzes the CDI-induced oligomerization of arginine, although it does not adsorb oligoarginines. These results are relevant to the formation of polypeptides on the primitive earth.

  11. Polymerization on the rocks: beta-amino acids and arginine.

    PubMed

    Liu, R; Orgel, L E

    1998-06-01

    We have studied the accumulation of long oligomers of beta-amino acids on the surface of minerals using the 'polymerization on the rocks' protocol. We find that long oligopeptides of beta-glutamic acid which cannot be formed in homogeneous aqueous solution are accumulated efficiently on the surface of hydroxylapatite using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as condensing agent. The EDAC-induced oligomerization of aspartic acid on hydroxylapatite proceeds even more efficiently. Hydroxylapatite can also facilitate the ligation of the tripeptide (glu)3. The 'polymerization on the rocks' scenario is not restricted to negatively-charged amino acids. Oligoarginines are accumulated on the surface of illite using carbonyldiimidizole (CDI) as condensing agent. We find that FeS2 catalyzes the CDI-induced oligomerization of arginine, although it does not adsorb oligoarginines. These results are relevant to the formation of polypeptides on the primitive earth.

  12. Polymerization on the rocks: beta-amino acids and arginine

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have studied the accumulation of long oligomers of beta-amino acids on the surface of minerals using the 'polymerization on the rocks' protocol. We find that long oligopeptides of beta-glutamic acid which cannot be formed in homogeneous aqueous solution are accumulated efficiently on the surface of hydroxylapatite using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as condensing agent. The EDAC-induced oligomerization of aspartic acid on hydroxylapatite proceeds even more efficiently. Hydroxylapatite can also facilitate the ligation of the tripeptide (glu)3. The 'polymerization on the rocks' scenario is not restricted to negatively-charged amino acids. Oligoarginines are accumulated on the surface of illite using carbonyldiimidizole (CDI) as condensing agent. We find that FeS2 catalyzes the CDI-induced oligomerization of arginine, although it does not adsorb oligoarginines. These results are relevant to the formation of polypeptides on the primitive earth.

  13. Amino Acid Uptake in Arbuscular Mycorrhizal Plants

    PubMed Central

    Whiteside, Matthew D.; Garcia, Maria O.; Treseder, Kathleen K.

    2012-01-01

    We examined the extent to which arbuscular mycorrhizal (AM) fungi root improved the acquisition of simple organic nitrogen (ON) compounds by their host plants. In a greenhouse-based study, we used quantum dots (fluorescent nanoparticles) to assess uptake of each of the 20 proteinaceous amino acids by AM-colonized versus uncolonized plants. We found that AM colonization increased uptake of phenylalanine, lysine, asparagine, arginine, histidine, methionine, tryptophan, and cysteine; and reduced uptake of aspartic acid. Arbuscular mycorrhizal colonization had the greatest effect on uptake of amino acids that are relatively rare in proteins. In addition, AM fungi facilitated uptake of neutral and positively-charged amino acids more than negatively-charged amino acids. Overall, the AM fungi used in this study appeared to improve access by plants to a number of amino acids, but not necessarily those that are common or negatively-charged. PMID:23094070

  14. Research for amino acids in lunar samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Rash, J. J.; Aue , W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

  15. Research for amino acids in lunar samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Rash, J. J.; Aue , W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

  16. Fmoc/Trt-amino acids: comparison to Fmoc/tBu-amino acids in peptide synthesis.

    PubMed

    Barlos, K; Gatos, D; Koutsogianni, S

    1998-03-01

    Model peptides containing the nucleophilic amino acids Trp and Met have been synthesized with the application of Fmoc/Trt- and Fmoc/tBu-amino acids, for comparison. The deprotection of the peptides synthesized using Fmoc/Trt-amino acids in all cases leads to crude peptides of higher purity than that of the same peptides synthesized using Fmoc/tBu-amino acids.

  17. Amino acid regulation of gene expression.

    PubMed Central

    Fafournoux, P; Bruhat, A; Jousse, C

    2000-01-01

    The impact of nutrients on gene expression in mammals has become an important area of research. Nevertheless, the current understanding of the amino acid-dependent control of gene expression is limited. Because amino acids have multiple and important functions, their homoeostasis has to be finely maintained. However, amino-acidaemia can be affected by certain nutritional conditions or various forms of stress. It follows that mammals have to adjust several of their physiological functions involved in the adaptation to amino acid availability by regulating the expression of numerous genes. The aim of the present review is to examine the role of amino acids in regulating mammalian gene expression and protein turnover. It has been reported that some genes involved in the control of growth or amino acid metabolism are regulated by amino acid availability. For instance, limitation of several amino acids greatly increases the expression of the genes encoding insulin-like growth factor binding protein-1, CHOP (C/EBP homologous protein, where C/EBP is CCAAT/enhancer binding protein) and asparagine synthetase. Elevated mRNA levels result from both an increase in the rate of transcription and an increase in mRNA stability. Several observations suggest that the amino acid regulation of gene expression observed in mammalian cells and the general control process described in yeast share common features. Moreover, amino acid response elements have been characterized in the promoters of the CHOP and asparagine synthetase genes. Taken together, the results discussed in the present review demonstrate that amino acids, by themselves, can, in concert with hormones, play an important role in the control of gene expression. PMID:10998343

  18. The Apollo Program and Amino Acids

    ERIC Educational Resources Information Center

    Fox, Sidney W.

    1973-01-01

    Discusses the determination of hydrolyzable amino acid precursors and a group of six amino acids in the returned lunar samples of the Apollo programs. Indicates that molecular evolution is arrested at the precursor stage on the Moon because of lack of water. (CC)

  19. 6th Amino Acid Assessment Workshop

    USDA-ARS?s Scientific Manuscript database

    The focus of the 6th workshop is on lysine, arginine, and related amino acids. Functions, metabolic pathways, clinical uses, and upper tolerance intakes are emphasized in the articles that follow. Lysine is arguably the most deficient amino acid in the food supply of countries where poverty exists, ...

  20. The Apollo Program and Amino Acids

    ERIC Educational Resources Information Center

    Fox, Sidney W.

    1973-01-01

    Discusses the determination of hydrolyzable amino acid precursors and a group of six amino acids in the returned lunar samples of the Apollo programs. Indicates that molecular evolution is arrested at the precursor stage on the Moon because of lack of water. (CC)

  1. Human Protein and Amino Acid Requirements.

    PubMed

    Hoffer, L John

    2016-05-01

    Human protein and amino acid nutrition encompasses a wide, complex, frequently misunderstood, and often contentious area of clinical research and practice. This tutorial explains the basic biochemical and physiologic principles that underlie our current understanding of protein and amino acid nutrition. The following topics are discussed: (1) the identity, measurement, and essentiality of nutritional proteins; (2) the definition and determination of minimum requirements; (3) nutrition adaptation; (4) obligatory nitrogen excretion and the minimum protein requirement; (5) minimum versus optimum protein intakes; (6) metabolic responses to surfeit and deficient protein intakes; (7) body composition and protein requirements; (8) labile protein; (9) N balance; (10) the principles of protein and amino acid turnover, including an analysis of the controversial indicator amino acid oxidation technique; (11) general guidelines for evaluating protein turnover articles; (12) amino acid turnover versus clearance; (13) the protein content of hydrated amino acid solutions; (14) protein requirements in special situations, including protein-catabolic critical illness; (15) amino acid supplements and additives, including monosodium glutamate and glutamine; and (16) a perspective on the future of protein and amino acid nutrition research. In addition to providing practical information, this tutorial aims to demonstrate the importance of rigorous physiologic reasoning, stimulate intellectual curiosity, and encourage fresh ideas in this dynamic area of human nutrition. In general, references are provided only for topics that are not well covered in modern textbooks. © 2016 American Society for Parenteral and Enteral Nutrition.

  2. Control of mammalian gene expression by amino acids, especially glutamine.

    PubMed

    Brasse-Lagnel, Carole; Lavoinne, Alain; Husson, Annie

    2009-04-01

    Molecular data rapidly accumulating on the regulation of gene expression by amino acids in mammalian cells highlight the large variety of mechanisms that are involved. Transcription factors, such as the basic-leucine zipper factors, activating transcription factors and CCAAT/enhancer-binding protein, as well as specific regulatory sequences, such as amino acid response element and nutrient-sensing response element, have been shown to mediate the inhibitory effect of some amino acids. Moreover, amino acids exert a wide range of effects via the activation of different signalling pathways and various transcription factors, and a number of cis elements distinct from amino acid response element/nutrient-sensing response element sequences were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine, the most abundant amino acid, which at appropriate concentrations enhances a great number of cell functions via the activation of various transcription factors. The glutamine-responsive genes and the transcription factors involved correspond tightly to the specific effects of the amino acid in the inflammatory response, cell proliferation, differentiation and survival, and metabolic functions. Indeed, in addition to the major role played by nuclear factor-kappaB in the anti-inflammatory action of glutamine, the stimulatory role of activating protein-1 and the inhibitory role of C/EBP homology binding protein in growth-promotion, and the role of c-myc in cell survival, many other transcription factors are also involved in the action of glutamine to regulate apoptosis and intermediary metabolism in different cell types and tissues. The signalling pathways leading to the activation of transcription factors suggest that several kinases are involved, particularly mitogen-activated protein kinases. In most cases, however, the precise pathways from the entrance of the amino acid into the cell to the activation of gene

  3. Protein biosynthesis with conformationally restricted amino acids

    SciTech Connect

    Mendel, D. Lawrence Berkeley Lab., CA ); Ellman, J.; Schultz, P.G. )

    1993-05-19

    The incorporation of conformationally constrained amino acids into peptides is a powerful approach for generating structurally defined peptides as conformational probes and bioactive agents. The ability to site-specifically introduce constrained amino acids into large polypeptide chains would provide a similar opportunity to probe the flexibility, conformation, folding and stability of proteins. To this end, we have examined the competence of the Escherichia coli protein biosynthetic machinery to incorporate a number of these unnatural amino acids into the 164 residue protein T4 lysozyme (T4L). Results clearly demonstrate that the protein biosynthetic machinery can accommodate a wide variety of conformationally constrained amino acids. The expansion of structural motifs that can be biosynthetically incorporated into proteins to include a large number of conformationally constrained amino acids significantly increases the power of mutagenesis methods as probes of protein structure and function and provides additional insights into the steric requirements of the translational machinery. 13 refs., 2 figs.

  4. Amino acid chemoreceptors of Bacillus subtilis.

    PubMed Central

    Ordal, G W; Villani, D P; Gibson, K J

    1977-01-01

    Specificities of chemoreceptors for the 20 common amino acids, toward which Bacillus subtilis shows chemotaxis, were assessed by competition ("jamming") experiments using a modification of the traditional capillary assay, called the "sensitivity capillary assay." Many amino acids were sensed by at least two chemoreceptors. All the highest affinity chemoreceptors for the amino acids were distinct, except glutamate and aspartate, which may share one chemoreceptor, and tyrosine, for which the data could not be collected due to low solubility. The data suggest the hypothesis that each amino acid-chemoreceptor complex binds to a different signaler (from each amino acid-chemoreceptor complex binds to a different signaler (from which signals travel to the flagella to modify behavior appropriately), and that many of the signalers can also bind other attractant-chemoreceptor complexes as antagonists (no signals to flagella). PMID:401491

  5. Differential distribution of amino acids in plants.

    PubMed

    Kumar, Vinod; Sharma, Anket; Kaur, Ravdeep; Thukral, Ashwani Kumar; Bhardwaj, Renu; Ahmad, Parvaiz

    2017-05-01

    Plants are a rich source of amino acids and their individual abundance in plants is of great significance especially in terms of food. Therefore, it is of utmost necessity to create a database of the relative amino acid contents in plants as reported in literature. Since in most of the cases complete analysis of profiles of amino acids in plants was not reported, the units used and the methods applied and the plant parts used were different, amino acid contents were converted into relative units with respect to lysine for statistical analysis. The most abundant amino acids in plants are glutamic acid and aspartic acid. Pearson's correlation analysis among different amino acids showed that there were no negative correlations between the amino acids. Cluster analysis (CA) applied to relative amino acid contents of different families. Alismataceae, Cyperaceae, Capparaceae and Cactaceae families had close proximity with each other on the basis of their relative amino acid contents. First three components of principal component analysis (PCA) explained 79.5% of the total variance. Factor analysis (FA) explained four main underlying factors for amino acid analysis. Factor-1 accounted for 29.4% of the total variance and had maximum loadings on glycine, isoleucine, leucine, threonine and valine. Factor-2 explained 25.8% of the total variance and had maximum loadings on alanine, aspartic acid, serine and tyrosine. 14.2% of the total variance was explained by factor-3 and had maximum loadings on arginine and histidine. Factor-4 accounted 8.3% of the total variance and had maximum loading on the proline amino acid. The relative content of different amino acids presented in this paper is alanine (1.4), arginine (1.8), asparagine (0.7), aspartic acid (2.4), cysteine (0.5), glutamic acid (2.8), glutamine (0.6), glycine (1.0), histidine (0.5), isoleucine (0.9), leucine (1.7), lysine (1.0), methionine (0.4), phenylalanine (0.9), proline (1.1), serine (1.0), threonine (1

  6. Amino acids in the Martian meteorite Nakhla.

    PubMed

    Glavin, D P; Bada, J L; Brinton, K L; McDonald, G D

    1999-08-03

    A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, beta-alanine, and gamma-amino-n-butyric acid (gamma-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

  7. Amino acids in the Martian meteorite Nakhla

    PubMed Central

    Glavin, Daniel P.; Bada, Jeffrey L.; Brinton, Karen L. F.; McDonald, Gene D.

    1999-01-01

    A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, β-alanine, and γ-amino-n-butyric acid (γ-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the d/l ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth. PMID:10430856

  8. Amino acids in the Martian meteorite Nakhla

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Bada, J. L.; Brinton, K. L.; McDonald, G. D.

    1999-01-01

    A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, beta-alanine, and gamma-amino-n-butyric acid (gamma-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

  9. Amino Acids in the Martian Meteorite Nakhla

    NASA Astrophysics Data System (ADS)

    Glavin, Daniel P.; Bada, Jeffrey L.; Brinton, Karen L. F.; McDonald, Gene D.

    1999-08-01

    A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, β -alanine, and γ -amino-n-butyric acid (γ -ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

  10. Exogenous amino acids as fuel in shock.

    PubMed

    Daniel, A M; Kapadia, B; MacLean, L D

    1982-01-01

    It has been suggested that in shock branched-chain amino acids are preferentially oxidized resulting in continued proteolysis and stimulated gluconeogenesis. To determine if exogenous amino acids could be used as fuel in shock, dogs rendered hypotensive by controlled cardiac tamponade and normotensive controls were infused with amino acid mixtures and individual amino acids. When Nephramine, a mixture rich in branched-chain amino acids, was infused, plasma alpha-amino nitrogen levels rose but urea output did not increase in either the control state or in shock, suggesting that these amino acids were not rapidly deaminated to serve as fuels. Travasol, which in addition contained large amounts of alanine and glycine, tripled urea output in the controls and doubled it in shock. The limit of urea production was reached in both groups at 35 mumoles urea/minute/kg. In the Travasol-infused animals plasma alpha-amino nitrogen levels were maintained in normotension but rose sharply in shock. When glycine alone was infused into five dogs in shock urea production rate was 30.6 + 2.1 mumoles/minute/kg; with alanine the same value was 22.5 + 2.2 mumoles/minute/kg. In both cases plasma alpha-amino nitrogen levels were high, suggesting that transport of these amino acids into the cell was slow in shock. In four dogs in shock glycine-14C was added to the glycine infusate as a tracer. At radioactive equilibrium 28% of the label infused appeared in CO2; another 22% appeared in glucose. It is concluded that of all the amino acids tested only glycine and alanine are deaminated rapidly enough to serve as exogenous fuels in shock.

  11. Gemini surfactants from natural amino acids.

    PubMed

    Pérez, Lourdes; Pinazo, Aurora; Pons, Ramon; Infante, Mrosa

    2014-03-01

    In this review, we report the most important contributions in the structure, synthesis, physicochemical (surface adsorption, aggregation and phase behaviour) and biological properties (toxicity, antimicrobial activity and biodegradation) of Gemini natural amino acid-based surfactants, and some potential applications, with an emphasis on the use of these surfactants as non-viral delivery system agents. Gemini surfactants derived from basic (Arg, Lys), neutral (Ser, Ala, Sar), acid (Asp) and sulphur containing amino acids (Cys) as polar head groups, and Geminis with amino acids/peptides in the spacer chain are reviewed.

  12. An overview on D-amino acids.

    PubMed

    Genchi, Giuseppe

    2017-07-05

    More than half a century ago researchers thought that D-amino acids had a minor function compared to L-enantiomers in biological processes. Many evidences have shown that D-amino acids are present in high concentration in microorganisms, plants, mammals and humans and fulfil specific biological functions. In the brain of mammals, D-serine (D-Ser) acts as a co-agonist of the N-methyl-D-aspartate (NMDA)-type glutamate receptors, responsible for learning, memory and behaviour. D-Ser metabolism is relevant for disorders associated with an altered function of the NMDA receptor, such as schizophrenia, ischemia, epilepsy and neurodegenerative disorders. On the other hand, D-aspartate (D-Asp) is one of the major regulators of adult neurogenesis and plays an important role in the development of endocrine function. D-Asp is present in the neuroendocrine and endocrine tissues and testes, and regulates the synthesis and secretion of hormones and spermatogenesis. Also food proteins contain D-amino acids that are naturally originated or processing-induced under conditions such as high temperatures, acid and alkali treatments and fermentation processes. The presence of D-amino acids in dairy products denotes thermal and alkaline treatments and microbial contamination. Two enzymes are involved in the metabolism of D-amino acids: amino acid racemase in the synthesis and D-amino acid oxidase in the degradation.

  13. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  14. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  15. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  16. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-10-06

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

  17. Amino acid transporters: roles in amino acid sensing and signalling in animal cells.

    PubMed Central

    Hyde, Russell; Taylor, Peter M; Hundal, Harinder S

    2003-01-01

    Amino acid availability regulates cellular physiology by modulating gene expression and signal transduction pathways. However, although the signalling intermediates between nutrient availability and altered gene expression have become increasingly well documented, how eukaryotic cells sense the presence of either a nutritionally rich or deprived medium is still uncertain. From recent studies it appears that the intracellular amino acid pool size is particularly important in regulating translational effectors, thus, regulated transport of amino acids across the plasma membrane represents a means by which the cellular response to amino acids could be controlled. Furthermore, evidence from studies with transportable amino acid analogues has demonstrated that flux through amino acid transporters may act as an initiator of nutritional signalling. This evidence, coupled with the substrate selectivity and sensitivity to nutrient availability classically associated with amino acid transporters, plus the recent discovery of transporter-associated signalling proteins, demonstrates a potential role for nutrient transporters as initiators of cellular nutrient signalling. Here, we review the evidence supporting the idea that distinct amino acid "receptors" function to detect and transmit certain nutrient stimuli in higher eukaryotes. In particular, we focus on the role that amino acid transporters may play in the sensing of amino acid levels, both directly as initiators of nutrient signalling and indirectly as regulators of external amino acid access to intracellular receptor/signalling mechanisms. PMID:12879880

  18. Aspartate-Derived Amino Acid Biosynthesis in Arabidopsis thaliana.

    PubMed

    Jander, Georg; Joshi, Vijay

    2009-01-01

    The aspartate-derived amino acid pathway in plants leads to the biosynthesis of lysine, methionine, threonine, and isoleucine. These four amino acids are essential in the diets of humans and other animals, but are present in growth-limiting quantities in some of the world's major food crops. Genetic and biochemical approaches have been used for the functional analysis of almost all Arabidopsis thaliana enzymes involved in aspartate-derived amino acid biosynthesis. The branch-point enzymes aspartate kinase, dihydrodipicolinate synthase, homoserine dehydrogenase, cystathionine gamma synthase, threonine synthase, and threonine deaminase contain well-studied sites for allosteric regulation by pathway products and other plant metabolites. In contrast, relatively little is known about the transcriptional regulation of amino acid biosynthesis and the mechanisms that are used to balance aspartate-derived amino acid biosynthesis with other plant metabolic needs. The aspartate-derived amino acid pathway provides excellent examples of basic research conducted with A. thaliana that has been used to improve the nutritional quality of crop plants, in particular to increase the accumulation of lysine in maize and methionine in potatoes.

  19. Modification of fetal plasma amino acid composition by placental amino acid exchangers in vitro

    PubMed Central

    Cleal, Jane K; Brownbill, Paul; Godfrey, Keith M; Jackson, John M; Jackson, Alan A; Sibley, Colin P; Hanson, Mark A; Lewis, Rohan M

    2007-01-01

    Fetal growth is dependent on both the quantity and relative composition of amino acids delivered to the fetal circulation, and impaired placental amino acid supply is associated with restricted fetal growth. Amino acid exchangers can alter the composition, but not the quantity, of amino acids in the intra- and extracellular amino acid pools. In the placenta, exchangers may be important determinants of the amino acid composition in the fetal circulation. This study investigates the substrate specificity of exchange between the placenta and the feto-placental circulation. Maternal–fetal transfer of radiolabelled amino acids and creatinine were measured in the isolated perfused human placental cotyledon. Transfer of l-[14C]serine or l-[14C]leucine, and [3H]glycine, were measured in the absence of amino acids in the fetal circulation (transfer by non-exchange mechanisms) and following 10–20 μmol boluses of unlabelled amino acids into the fetal circulation to provide substrates for exchange (transfer by exchange and non-exchange mechanisms). The ability of fetal arterial boluses of l-alanine and l-leucine to stimulate release of amino acids from the placenta was also determined using HPLC in order to demonstrate the overall pattern of amino acid release. Experiments with radiolabelled amino acids demonstrated increased maternal–fetal transfer of l-serine and l-leucine, but not glycine, following boluses of specific amino acids into the fetal circulation. l-[14C]Leucine, but not l-[14C]serine or [3H]glycine, was transferred from the maternal to the fetal circulation by non-exchange mechanisms also (P < 0.01). HPLC analysis demonstrated that fetal amino acid boluses stimulated increased transport of a range of different amino acids by 4–7 μmol l−1 (P < 0.05). Amino acid exchange provides a mechanism to supply the fetus with amino acids that it requires for fetal growth. This study demonstrates that these transporters have the capacity to exchange micromolar

  20. Amino Acid Stability in the Early Oceans

    NASA Technical Reports Server (NTRS)

    Parker, E. T.; Brinton, K. L.; Burton, A. S.; Glavin, D. P.; Dworkin, J. P.; Bada, J. L.

    2015-01-01

    It is likely that a variety of amino acids existed in the early oceans of the Earth at the time of the origin and early evolution of life. "Primordial soup", hydrothermal vent, and meteorite based processes could have contributed to such an inventory. Several "protein" amino acids were likely present, however, based on prebiotic synthesis experiments and carbonaceous meteorite studies, non-protein amino acids, which are rare on Earth today, were likely the most abundant. An important uncertainty is the length of time these amino acids could have persisted before their destruction by abiotic and biotic processes. Prior to life, amino acid concentrations in the oceans were likely regulated by circulation through hydro-thermal vents. Today, the entire ocean circulates through vent systems every 10(exp 7) years. On the early Earth, this value was likely smaller due to higher heat flow and thus marine amino acid life-time would have been shorter. After life, amino acids in the oceans could have been assimilated by primitive organisms.

  1. Enantiomer-specific selection of amino acids

    PubMed Central

    Ren, Xueying; Tellez, Luis A; de Araujo, Ivan E

    2013-01-01

    Dietary intake of L-amino acids impacts on several physiological functions, including the control of gastrointestinal motility, pancreatic secretion, and appetite. However, the biological mechanisms regulating behavioral predilections for certain amino acid types remain poorly understood. We tested the hypothesis that, in mice, the potency with which a given glucogenic amino acid increases glucose utilization reflects its rewarding properties. We have found that: 1. During long-, but not short-, term preference tests, L-alanine and L-serine were preferred over their D-enantiomer counterparts, while no such effect was observed for L-threonine vs. D-threonine; 2. These behavioral patterns were closely associated with the ability of L-amino acids to promote increases in respiratory exchange ratios such that those, and only those, L-amino acids able to promote increases in respiratory exchange ratios were preferred over their D-isomers; 3. These behavioral preferences were independent of gustatory influences, since taste-deficient Trpm5 knockout mice displayed ingestive responses very similar to those of their wild-type counterparts. We conclude that the ability to promote increases in respiratory exchange ratios enhances the reward value of nutritionally relevant amino acids, and suggest a mechanistic link between substrate utilization and amino acid preferences. PMID:24072505

  2. Amino Acid Detection in Cometary Matter?

    NASA Astrophysics Data System (ADS)

    Meierhenrich, U. J.; Munoz Caro, G. M.; Thiemann, W.; Goesmann, F.; Rosenbauer, H.

    2003-04-01

    The recent identification of amino acid structures in interstellar ice analogues [1, 2] strongly supports the assumption that amino acids are abundant in cometary matter too. Cometary matter is assumed to be built up of aggregates of interstellar dust particles. Amino acids are the molecular building blocks of proteins in living organisms. These results amplified the scientific interest in the ESA cometary mission Rosetta. The Rosetta Lander includes the Cosac experiment dedicated to the identification of chiral organic molecules in cometary matter itshape in situ \\upshape by multi column gas chromatography coupled with a reflectron time-of-flight mass spectrometer. However, the envisaged itshape in situ \\upshape amino acid analysis on the cometary surface requires special technical emphasis of the COSAC instrumentation. The context in which the amino acid identification in cometary matter is of interest will be outlined and the analytical solutions that make amino acids accessible to the COSAC instrument will be presented. A succesful identification of amino acid structures in cometary matter would help to understand the beginnings of the biomolecular evolution and the origin of the biomolecular asymmetry. [1] G.M. Muñoz Caro, U.J. Meierhenrich, W.A. Schutte, B. Barbier, A. Arcones Sergovia, H. Rosenbauer, W.H.-P. Thiemann, A. Brack, J.M. Greenberg: itshape Nature \\upshape 416 (2002), 403-406. [2] M.P. Bernstein, J.P. Dworkin, S.A. Sandford, G.W. Cooper, L.J. Allamandola: itshape Nature \\upshape 416 (2002), 401-403.

  3. Distribution of Amino Acids in Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Noble, S. K.; Gibson, E. K., Jr.

    2014-01-01

    One of the most eagerly studied questions upon initial return of lunar samples was whether significant amounts of organic compounds, including amino acids, were present. Analyses during the 1970s produced only tentative and inconclusive identifications of indigenous amino acids. Those analyses were hampered by analytical difficulties including relative insensitivity to certain compounds, the inability to separate chiral enantiomers, and the lack of compound-specific isotopic measurements, which made it impossible to determine whether the detected amino acids were indigenous to the lunar samples or the results of contamination. Numerous advances have been made in instrumentation and methodology for amino acid characterization in extraterrestrial samples in the intervening years, yet the origin of amino acids in lunar regolith samples has been revisited only once for a single lunar sample, (3) and remains unclear. Here, we present initial data from the analyses of amino acid abundances in 12 lunar regolith samples. We discuss these abundances in the context of four potential amino acid sources: (1) terrestrial biological contamination; (2) contamination from lunar module (LM) exhaust; (3) derivation from solar windimplanted precursors; and (4) exogenous delivery from meteorites.

  4. Amino Acid Degradation after Meteoritic Impact Simulation

    NASA Technical Reports Server (NTRS)

    Bertrand, M.; Westall, F.; vanderGaast, S.; Vilas, F.; Hoerz, F.; Barnes, G.; Chabin, A.; Brack, A.

    2008-01-01

    Amino acids are among the most important prebiotic molecules as it is from these precursors that the building blocks of life were formed [1]. Although organic molecules were among the components of the planetesimals making up the terrestrial planets, large amounts of primitive organic precursor molecules are believed to be exogenous in origin and to have been imported to the Earth via micrometeorites, carbonaceous meteorites and comets, especially during the early stages of the formation of the Solar System [1,2]. Our study concerns the hypothesis that prebiotic organic matter, present on Earth, was synthesized in the interstellar environment, and then imported to Earth by meteorites or micrometeorites. We are particularly concerned with the formation and fate of amino acids. We have already shown that amino acid synthesis is possible inside cometary grains under interstellar environment conditions [3]. We are now interested in the effects of space conditions and meteoritic impact on these amino acids [4-6]. Most of the extraterrestrial organic molecules known today have been identified in carbonaceous chondrite meteorites [7]. One of the components of these meteorites is a clay with a composition close to that of saponite, used in our experiments. Two American teams have studied the effects of impact on various amino acids [8,9]. [8] investigated amino acids in saturated solution in water with pressure ranges between 5.1 and 21 GPa and temperature ranges between 412 and 870 K. [9] studied amino acids in solid form associated with and without minerals (Murchison and Allende meteorite extracts) and pressure ranges between 3 and 30 GPa. In these two experiments, the amino acids survived up to 15 GPa. At higher pressure, the quantity of preserved amino acids decreases quickly. Some secondary products such as dipeptides and diketopiperazins were identified in the [8] experiment.

  5. Amino Acid Derangements in Patients With Sepsis: Treatment With Branched Chain Amino Acid Rich Infusions

    PubMed Central

    Freund, Herbert R.; Ryan, John A.; Fischer, Josef E.

    1978-01-01

    Sepsis is a major catabolic insult resulting in modifications in carbohydrate and fat energy metabolism, and leading to increased muscle breakdown and nitrogen loss. Insulin resistance, which develops in sepsis, decreases glucose utilization, but plasma insulin levels are sufficiently elevated to prevent lipolysis, resulting in a further energy deficit. The availability of fuels in sepsis is therefore limited, and the body resorts to muscle breakdown, gluconeogenesis, and amino acid oxidation for energy supply. Previous work has not defined, however, the exact alterations in amino acid metabolism. Therefore, the following studies were undertaken. Blood samples were drawn from fifteen patients in whom the diagnosis of sepsis was clinically established; the samples were analyzed for amino acid, β-hydroxyphenylethanolamines, glucose, insulin and glucagon concentrations. The plasma amino acid pattern observed was characterized by an increase in total amino acid content, due mainly to high levels of the aromatic amino acids (phenylalanine and tyrosine) and the sulfur-containing amino acids (taurine, cystine and methionine). Alanine, aspartic acid, glutamic acid and proline were also elevated, but to a lesser degree. The branched chain amino acids (valine, leucine and isoleucine) were within normal limits, as were glycine, serine, threonine, lysine, histidine and tryptophan. Those patients who did not survive sepsis had higher levels of aromatic and sulfur-containing amino acids as compared to those patients surviving sepsis. On the other hand, those patients surviving sepsis had higher levels of alanine and the branched chain amino acids. In a second group of five patients with overwhelming sepsis accompanied by a state of metabolic encephalopathy, a parenteral nutrition solution consisting of 23% dextrose, and an amino acid formulation enriched with branched chain amino acids was administered. In these five patients, normalization of the plasma amino acid pattern and

  6. Amino acid analysis for pharmacopoeial purposes.

    PubMed

    Wahl, Oliver; Holzgrabe, Ulrike

    2016-07-01

    The impurity profile of amino acids depends strongly on the production process. Since there are many different production methods (e.g. fermentation, protein hydrolysis or chemical synthesis) universal, state of the art methods are required to determine the impurity profile of amino acids produced by all relevant competitors. At the moment TLC tests provided by the Ph. Eur. are being replaced by a very specific amino acid analysis procedure possibly missing out on currently unknown process related impurities. Production methods and possible impurities as well as separation and detection methods suitable for said impurities are subject to this review. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. ANTIGENICITY OF POLYPEPTIDES (POLY ALPHA AMINO ACIDS)

    PubMed Central

    Pinchuck, Paul; Maurer, Paul H.

    1965-01-01

    The response of mice to synthetic linear polypeptides of known composition but random sequence has been studied. Neither Swiss mice nor a number of inbred strains could respond to copolymers of only 2 amino acids (G60L40, G60A40, G90T10). Upon introduction of as little as 4 mole per cent of a third amino acid, good immune responses were obtained, regardless of the nature of the third amino acid. The level of the immune response to a series of glu-lys-ala polymers increased with increasing alanine content of the polymer. PMID:5849232

  8. Regulation of the plasma amino acid profile by leucine via the system L amino acid transporter.

    PubMed

    Zhen, Hongmin; Nakamura, Koichi; Kitaura, Yasuyuki; Kadota, Yoshihiro; Ishikawa, Takuya; Kondo, Yusuke; Xu, Minjun; Shimomura, Yoshiharu

    2015-01-01

    Plasma concentrations of amino acids reflect the intracellular amino acid pool in mammals. However, the regulatory mechanism requires clarification. In this study, we examined the effect of leucine administration on plasma amino acid profiles in mice with and without the treatment of 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) or rapamycin as an inhibitor of system L or mammalian target of rapamycin complex 1, respectively. The elevation of plasma leucine concentration after leucine administration was associated with a significant decrease in the plasma concentrations of isoleucine, valine, methionine, phenylalanine, and tyrosine; BCH treatment almost completely blocked the leucine-induced decrease in plasma amino acid concentrations. Rapamycin treatment had much less effects on the actions of leucine than BCH treatment. These results suggest that leucine regulates the plasma concentrations of branched-chain amino acids, methionine, phenylalanine, and tyrosine, and that system L amino acid transporters are involved in the leucine action.

  9. Amino acid odorants stimulate microvillar sensory neurons.

    PubMed

    Lipschitz, David L; Michel, William C

    2002-03-01

    The olfactory epithelium (OE) of zebrafish is populated with ciliated and microvillar olfactory sensory neurons (OSNs). Whether distinct classes of odorants specifically activate either of these unique populations of OSNs is unknown. Previously we demonstrated that zebrafish OSNs could be labeled in an activity-dependent fashion by amino acid but not bile acid odorants. To determine which sensory neuron type was stimulated by amino acid odorants, we labeled OSNs using the ion channel permeant probe agmatine (AGB) and analyzed its distribution with conventional light- and electron-microscope immunocytochemical techniques. Approximately 7% of the sensory epithelium was labeled by AGB exposure alone. Following stimulation with one of the eight amino acids tested, the proportion of labeled epithelium increased from 9% for histidine to 19% for alanine; amino acid stimulated increases in labeling of 2-12% over control labeling. Only histidine failed to stimulate a significant increase in the proportion of labeled OSNs compared to control preparations. Most amino acid sensitive OSNs were located superficially in the epithelium and immuno-electron microscopy demonstrated that the labeled OSNs were predominantly microvillar. Large numbers of nanogold particles (20-60 per 1.5 microm(2)) were associated with microvillar olfactory sensory neurons (MSNs), while few such particles (<15 per 1.5 microm(2)) were observed over ciliated olfactory sensory neurons (CSNs), supporting cells (SCs) and areas without tissue, such as the lumen above the OE. Collectively, these findings indicate that microvillar sensory neurons are capable of detecting amino acid odorants.

  10. Discovery and History of Amino Acid Fermentation.

    PubMed

    Hashimoto, Shin-Ichi

    2016-12-02

    There has been a strong demand in Japan and East Asia for L-glutamic acid as a seasoning since monosodium glutamate was found to present umami taste in 1907. The discovery of glutamate fermentation by Corynebacterium glutamicum in 1956 enabled abundant and low-cost production of the amino acid, creating a large market. The discovery also prompted researchers to develop fermentative production processes for other L-amino acids, such as lysine. Currently, the amino acid fermentation industry is so huge that more than 5 million metric tons of amino acids are manufactured annually all over the world, and this number continues to grow. Research on amino acid fermentation fostered the notion and skills of metabolic engineering which has been applied for the production of other compounds from renewable resources. The discovery of glutamate fermentation has had revolutionary impacts on both the industry and science. In this chapter, the history and development of glutamate fermentation, including the very early stage of fermentation of other amino acids, are reviewed.

  11. Genetics Home Reference: aromatic l-amino acid decarboxylase deficiency

    MedlinePlus

    ... aromatic l-amino acid decarboxylase deficiency aromatic l-amino acid decarboxylase deficiency Printable PDF Open All Close All ... view the expand/collapse boxes. Description Aromatic l-amino acid decarboxylase (AADC) deficiency is an inherited disorder that ...

  12. Amino Acid Biosynthesis Pathways in Diatoms

    PubMed Central

    Bromke, Mariusz A.

    2013-01-01

    Amino acids are not only building blocks for proteins but serve as precursors for the synthesis of many metabolites with multiple functions in growth and other biological processes of a living organism. The biosynthesis of amino acids is tightly connected with central carbon, nitrogen and sulfur metabolism. Recent publication of genome sequences for two diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum created an opportunity for extensive studies on the structure of these metabolic pathways. Based on sequence homology found in the analyzed diatomal genes, the biosynthesis of amino acids in diatoms seems to be similar to higher plants. However, one of the most striking differences between the pathways in plants and in diatomas is that the latter possess and utilize the urea cycle. It serves as an important anaplerotic pathway for carbon fixation into amino acids and other N-containing compounds, which are essential for diatom growth and contribute to their high productivity. PMID:24957993

  13. Enantioenrichment in sublimed amino acid mixtures.

    PubMed

    Viedma, Cristóbal; Ortiz, José E; de Torres, Trinidad; Cintas, Pedro

    2012-04-14

    A real amplification of an initial enantiomeric excess can be detected when two amino acids are sublimed at high temperature, even if one of the components is a racemic compound that does not convert into a conglomerate by sublimation.

  14. Amino acid interaction preferences in proteins

    PubMed Central

    Nath Jha, Anupam; Vishveshwara, Saraswathi; Banavar, Jayanth R

    2010-01-01

    Understanding the key factors that influence the interaction preferences of amino acids in the folding of proteins have remained a challenge. Here we present a knowledge-based approach for determining the effective interactions between amino acids based on amino acid type, their secondary structure, and the contact based environment that they find themselves in the native state structure as measured by their number of neighbors. We find that the optimal information is approximately encoded in a 60 × 60 matrix describing the 20 types of amino acids in three distinct secondary structures (helix, beta strand, and loop). We carry out a clustering scheme to understand the similarity between these interactions and to elucidate a nonredundant set. We demonstrate that the inferred energy parameters can be used for assessing the fit of a given sequence into a putative native state structure. PMID:20073083

  15. Production of amino acids by yogurt bacteria.

    PubMed

    Beshkova, D M; Simova, E D; Frengova, G I; Simov, Z I; Adilov, E F

    1998-01-01

    The dynamics of free amino acid production by the selected strains Streptococcus thermophilus 13a and Lactobacillus bulgaricus 2-11 were studied in pure and mixed cultivations during yogurt starter culture manufacture. L. bulgaricus 2-11 showed the highest activity for producing free amino acids with high individual concentrations over the first hour of growth (50% of the total amount). By the end of milk's full coagulation (4.5 h), 70% of the total amount of amino acids was released. S. thermophilus 13a showed poor proteolytic properties and consumed up to 70% of the free amino acids produced by L. bulgaricus 2-11 in the process of coagulation of milk with the mixed culture.

  16. Genetically encoded fluorescent coumarin amino acids

    DOEpatents

    Wang, Jiangyun [San Diego, CA; Xie, Jianming [San Diego, CA; Schultz, Peter G [La Jolla, CA

    2012-06-05

    The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.

  17. Genetically encoded fluorescent coumarin amino acids

    DOEpatents

    Wang, Jiangyun; Xie, Jianming; Schultz, Peter G.

    2010-10-05

    The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl) ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.

  18. Nonprotein Amino Acids from Spark Discharges and Their Comparison with the Murchison Meteorite Amino Acids

    PubMed Central

    Wolman, Yecheskel; Haverland, William J.; Miller, Stanley L.

    1972-01-01

    All the nonprotein amino acids found in the Murchison meteorite are products of the action of electric discharge on a mixture of methane, nitrogen, and water with traces of ammonia. These amino acids include α-amino-n-butyric acid, α-aminoisobutyric acid, norvaline, isovaline, pipecolic acid, β-alanine, β-amino-n-butyric acid, β-aminoisobutyric acid, γ-aminobutyric acid, sarcosine, N-ethylglycine, and N-methylalanine. In addition, norleucine, alloisoleucine, N-propylglycine, N-isopropylglycine, N-methyl-β-alanine, N-ethyl-β-alanine α,β-diaminopropionic acid, isoserine, α,γ-diaminobutyric acid, and α-hydroxy-γ-aminobutyric acid are produced by the electric discharge, but have not been found in the meteorite. PMID:16591973

  19. Evaluation of amino acids as turfgrass nematicides.

    PubMed

    Zhang, Yun; Luc, John E; Crow, William T

    2010-12-01

    Laboratory experiments revealed that DL-methionine, sodium methionate, potassium methionate, and methionine hydroxyl analog at rates of 224 and 448 kg amino acid/ha reduced the number of Belonolaimus longicaudatus mixed life-stages and Meloidogyne incognita J2 in soil, whereas L-threonine and lysine were not effective in reducing the number of either nematode. Futhermore, greenhouse experiments demonstrated that DL-methionine, sodium methionate, potassium methionate, and methionine hydroxyl analog were equally effective against B. longicaudatus at rates of 112, 224, and 448 kg amino acid/ha, and the highest rate (448 kg amino acid/ha) of all amino acids was more effective in reducing the number of B. longicaudatus than the lower rate. However, phytotoxicity was observed on creeping bentgrass (Agrostis palustris) treated with 448 kg amino acid/ha of methionine hydroxyl analog and DL methionine. In addition, in one of two field experiments on bermudagrass (Cynodon dactylon × C. transvaalensis) turf percentage green cover was increased and the number of B. longicaudatus was reduced by 224 kg amino acid/ha of DL-methionine and potassium methionate compared to untreated controls in one of two trials.

  20. Free amino acids in spider hemolymph.

    PubMed

    Tillinghast, Edward K; Townley, Mark A

    2008-11-01

    We examined the free amino acid composition of hemolymph from representatives of five spider families with an interest in knowing if the amino acid profile in the hemolymph of orb-web-building spiders reflects the high demands for small organic compounds in the sticky droplets of their webs. In nearly all analyses, on both orb and non-orb builders, glutamine was the most abundant free amino acid. Glycine, taurine, proline, histidine, and alanine also tended to be well-represented in orb and non-orb builders. While indications of taxon-specific differences in amino acid composition were observed, it was not apparent that two presumptive precursors (glutamine, taurine) of orb web sticky droplet compounds were uniquely enriched in araneids (orb builders). However, total amino acid concentrations were invariably highest in the araneids and especially so in overwintering juveniles, even as several of the essential amino acids declined during this winter diapause. Comparing the data from this study with those from earlier studies revealed a number of discrepancies. The possible origins of these differences are discussed.

  1. Amino acid composition and amino acid-metabolic network in supragingival plaque.

    PubMed

    Washio, Jumpei; Ogawa, Tamaki; Suzuki, Keisuke; Tsukiboshi, Yosuke; Watanabe, Motohiro; Takahashi, Nobuhiro

    2016-01-01

    Dental plaque metabolizes both carbohydrates and amino acids. The former can be degraded to acids mainly, while the latter can be degraded to various metabolites, including ammonia, acids and amines, and associated with acid-neutralization, oral malodor and tissue inflammation. However, amino acid metabolism in dental plaque is still unclear. This study aimed to elucidate what kinds of amino acids are available as metabolic substrates and how the amino acids are metabolized in supragingival plaque, by a metabolome analysis. Amino acids and the related metabolites in supragingival plaque were extracted and quantified comprehensively by CE-TOFMS. Plaque samples were also incubated with amino acids, and the amounts of ammonia and amino acid-related metabolites were measured. The concentration of glutamate was the highest in supragingival plaque, while the ammonia-production was the highest from glutamine. The obtained metabolome profile revealed that amino acids are degraded through various metabolic pathways, including deamination, decarboxylation and transamination and that these metabolic systems may link each other, as well as with carbohydrate metabolic pathways in dental plaque ecosystem. Moreover, glutamine and glutamate might be the main source of ammonia production, as well as arginine, and contribute to pH-homeostasis and counteraction to acid-induced demineralization in supragingival plaque.

  2. Relation between chemotaxis and consumption of amino acids in bacteria

    PubMed Central

    Yang, Yiling; M. Pollard, Abiola; Höfler, Carolin; Poschet, Gernot; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    Summary Chemotaxis enables bacteria to navigate chemical gradients in their environment, accumulating toward high concentrations of attractants and avoiding high concentrations of repellents. Although finding nutrients is likely to be an important function of bacterial chemotaxis, not all characterized attractants are nutrients. Moreover, even for potential nutrients, the exact relation between the metabolic value of chemicals and their efficiency as chemoattractants has not been systematically explored. Here we compare the chemotactic response of amino acids with their use by bacteria for two well‐established models of chemotactic behavior, E scherichia coli and B acillus subtilis. We demonstrate that in E . coli chemotaxis toward amino acids indeed strongly correlates with their utilization. However, no such correlation is observed for B . subtilis, suggesting that in this case, the amino acids are not followed because of their nutritional value but rather as environmental cues. PMID:25807888

  3. Evidence of Selection for Low Cognate Amino Acid Bias in Amino Acid Biosynthetic Enzymes

    PubMed Central

    Alves, Rui; Savageau, Michael A.

    2006-01-01

    Summary If the enzymes responsible for biosynthesis of a given amino acid are repressed and the cognate amino acid pool suddenly depleted, then derepression of these enzymes and replenishment of the pool would be problematic, if the enzymes were largely composed of the cognate amino acid. In the proverbial ‘Catch 22’, cells would lack the necessary enzymes to make the amino acid, and they would lack the necessary amino acid to make the needed enzymes. Based on this scenario, we hypothesize that evolution would lead to the selection of amino acid biosynthetic enzymes that have a relatively low content of their cognate amino acid. We call this the ‘cognate bias hypothesis’. Here we test several implications of this hypothesis directly using data from the proteome of Escherichia coli. Several lines of evidence show that low cognate bias is evident in 15 of the 20 amino acid biosynthetic pathways. Comparison with closely related Salmonella typhimurium shows similar results. Comparison with more distantly related Bacillus subtilis shows general similarities as well as significant differences in the detailed profiles of cognate bias. Thus, selection for low cognate bias plays a significant role in shaping the amino acid composition for a large class of cellular proteins. PMID:15853887

  4. [Overproduction of noncanonical amino acids by Escherichia coli cells].

    PubMed

    Sycheva, E V; Iampol'skaia, T A; Preobrazhenskaia, E S; Novikova, A E; Matrosov, N G; Stoĭnova, N V

    2007-01-01

    Overproduction of noncanonical amino acids norvaline and norleucine by Escherichia coli with inactivated acetohydroxy acid synthases was demonstrated. The cultivation conditions for the overproduction of noncanonical amino acids were studied. The effect of the restoration of acetohydroxy acid synthase activity, increased expression of the leuABCD operon, and inactivation of the biosynthetic threonine deaminase on norvaline and norleucine synthesis was studied. When grown under valine limitation, E. coli cells with inactivated acetohydroxy acid synthases and an elevated level of expression of the valine operon were shown to accumulate norvaline and norleucine (up to 0.8 and 4 g/l, respectively). These results confirm the existing hypothesis of norvaline and norleucine formation from 2-ketobutyrate by leucine biosynthesis enzymes.

  5. Proteomic analysis of amino acid metabolism differences between wild and cultivated Panax ginseng

    PubMed Central

    Sun, Hang; Liu, Fangbing; Sun, Liwei; Liu, Jianzeng; Wang, Manying; Chen, Xuenan; Xu, Xiaohao; Ma, Rui; Feng, Kai; Jiang, Rui

    2015-01-01

    Background The present study aimed to compare the relative abundance of proteins and amino acid metabolites to explore the mechanisms underlying the difference between wild and cultivated ginseng (Panax ginseng Meyer) at the amino acid level. Methods Two-dimensional polyacrylamide gel electrophoresis and isobaric tags for relative and absolute quantitation were used to identify the differential abundance of proteins between wild and cultivated ginseng. Total amino acids in wild and cultivated ginseng were compared using an automated amino acid analyzer. The activities of amino acid metabolism-related enzymes and the contents of intermediate metabolites between wild and cultivated ginseng were measured using enzyme-linked immunosorbent assay and spectrophotometric methods. Results Our results showed that the contents of 14 types of amino acids were higher in wild ginseng compared with cultivated ginseng. The amino acid metabolism-related enzymes and their derivatives, such as glutamate decarboxylase and S-adenosylmethionine, all had high levels of accumulation in wild ginseng. The accumulation of sulfur amino acid synthesis-related proteins, such as methionine synthase, was also higher in wild ginseng. In addition, glycolysis and tricarboxylic acid cycle-related enzymes as well as their intermediates had high levels of accumulation in wild ginseng. Conclusion This study elucidates the differences in amino acids between wild and cultivated ginseng. These results will provide a reference for further studies on the medicinal functions of wild ginseng. PMID:27158231

  6. Amino acids in modern and fossil woods

    NASA Technical Reports Server (NTRS)

    Lee, C.; Bada, J. L.; Peterson, E.

    1976-01-01

    The amino acid composition and the extent of racemization in several modern and fossil woods are reported. The method of analysis is described, and data are presented on the total amino acid concentration, the amino acid ratios, and the enantiomeric ratios in each sample. It is found that the amino acid concentration per gram of dry wood decreases with age of the sample, that the extent of racemization increases with increasing age, and that the amounts of aspartic acid, threonine, and serine decrease relative to valine with increasing age. The relative racemization rates of amino acids in wood, bone, and aqueous solution are compared, and it is shown that racemization in wood is much slower than in bone or aqueous solution. Racemization results for woods from the Kalambo Falls area of Zambia are used to calculate a minimum age of 110,000 years for the transition between the Sangoan and Acheulian industries at that site. This result is shown to be consistent with numerous radiometric dates for older Acheulian sites in Africa and to compare well with geologically inferred dates for the beginning of the Eemian and the end of the Acheulian industry in southern Africa.

  7. Amino acids in modern and fossil woods

    NASA Technical Reports Server (NTRS)

    Lee, C.; Bada, J. L.; Peterson, E.

    1976-01-01

    The amino acid composition and the extent of racemization in several modern and fossil woods are reported. The method of analysis is described, and data are presented on the total amino acid concentration, the amino acid ratios, and the enantiomeric ratios in each sample. It is found that the amino acid concentration per gram of dry wood decreases with age of the sample, that the extent of racemization increases with increasing age, and that the amounts of aspartic acid, threonine, and serine decrease relative to valine with increasing age. The relative racemization rates of amino acids in wood, bone, and aqueous solution are compared, and it is shown that racemization in wood is much slower than in bone or aqueous solution. Racemization results for woods from the Kalambo Falls area of Zambia are used to calculate a minimum age of 110,000 years for the transition between the Sangoan and Acheulian industries at that site. This result is shown to be consistent with numerous radiometric dates for older Acheulian sites in Africa and to compare well with geologically inferred dates for the beginning of the Eemian and the end of the Acheulian industry in southern Africa.

  8. Amino acid survival in large cometary impacts

    NASA Astrophysics Data System (ADS)

    Pierazzo, E.; Chyba, C. F.

    1999-11-01

    A significant fraction of the Earth's prebiotic volatile inventory may have been delivered by asteroidal and cometary impacts during the period of heavy bombardment. The realization that comets are particularly rich in organic material seemed to strengthen this suggestion. Previous modeling studies, however, indicated that most organics would be entirely destroyed in large comet and asteroid impacts. The availability of new kinetic parameters for the thermal degradation of amino acids in the solid phase made it possible to readdress this question. We present the results of new high-resolution hydrocode simulations of asteroid and comet impact coupled with recent experimental data for amino acid pyrolysis in the solid phase. Differences due to impact velocity as well as projectile material have been investigated. Effects of angle of impacts were also addressed. The results suggest that some amino acids would survive the shock heating of large (kilometer-radius) cometary impacts. At the time of the origins of life on Earth, the steady-state oceanic concentration of certain amino acids (like aspartic and glutamic acid) delivered by comets could have equaled or substantially exceeded that due to Miller-Urey synthesis in a carbon dioxide-rich atmosphere. Furthermore, in the unlikely case of a grazing impact (impact angle around 5 degrees from the horizontal) an amount of some amino acids comparable to that due to the background steady-state production or delivery would be delivered to the early Earth.

  9. Amino acids derived from Titan tholins

    NASA Technical Reports Server (NTRS)

    Khare, B. N.; Sagan, C.; Ogino, H.; Nagy, B.; Er, C.; Schram, K. H.; Arakawa, E. T.

    1986-01-01

    An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan. Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns. Identifications were confirmed by GC/MS. Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea. The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin. In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface. These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.

  10. Trifluoroselenomethionine: A new unnatural amino acid

    USDA-ARS?s Scientific Manuscript database

    Trifluoroselenomethionine (TFSeM), a novel non-natural amino acid, was synthesized in seven steps from N-(tert-butoxycarbonyl)-L-aspartic acid tert-butyl ester. TFSeM shows enhanced methioninase-induced cytotoxicity toward human colon cancer derived HCT- 116 cells compared to selenomethionine (SeM)....

  11. Amino acid isotopic analysis in agricultural systems

    USDA-ARS?s Scientific Manuscript database

    A relatively new approach to stable isotopic analysis—referred to as compound-specific isotopic analysis (CSIA)—has emerged, centering on the measurement of 15N:14N ratios in amino acids (glutamic acid and phenylalanine). CSIA has recently been used to generate trophic position estimates among anima...

  12. [Dependence of metabolic fecal amino acids on the amino acid content of the feed. 1. Metabolic fecal amino acids of rats fed with maize].

    PubMed

    Krawielitzki, K; Schadereit, R; Völker, T; Reichel, K

    1981-07-01

    The amount of metabolic fecal amino acids (MFAA) in dependence on the amino acid intake was determined for graded maize rations with 15N-labelled rats and the quota of labelled endogenous amino acids in faeces was calculated according to the isotope dilution method. The excretion of amino acids and MFAA in faeces are described as functions of the amino acid intake for 17 amino acids and regressively calculated. For all 17 amino acids investigated, there was a more or less steep increase of MFAA according to an increasing amino acid intake. In contrast to MFAA in N-free feeding, MFAA in feeding with pure maize (16.5% crude protein) increase to the 2- to 4.5-fold value. The thesis of the constancy of the excretion of MFAA can consequently be no longer maintained. The true digestibility according to the conventional method is, on an average of all amino acids, 7.3 units below the one ascertained according to the 15N-isotope method. For the limiting amino acids lysine and threonine the difference is biggest (23 resp. 17 units). Tryptophane as first limiting amino acid could not be determined. The true digestibility of nearly all amino acids ascertained for maize according to the isotope method is above 90%. For the limiting amino acids the expenditure resp. the loss of endogenous amino acids is biggest.

  13. Analysis of amino acids by miniaturised isotachophoresis.

    PubMed

    Prest, Jeff E; Baldock, Sara J; Fielden, Peter R; Goddard, Nicholas J; Brown, Bernard J Treves

    2004-10-08

    A method allowing the miniaturised isotachophoretic analysis of amino acids has been developed. To overcome the problems of carbonate contamination which occur when performing separations at alkaline pH levels glycolate was used as the leading ion. Addition of magnesium to the leading electrolyte as a counter species was found to improve the separations. The method has been used on a poly(methyl methacrylate) microdevice with integrated on-column conductivity detectors. The behaviour of a range of common amino acids was investigated and successful separations of up to seven amino acids were made. Good linearity was observed with calibration curves for aspartic acid and phenylalanine over the range 0.063-1.0 mM. Limits of detection for these two species were calculated to be 0.060 and 0.018 mM, respectively.

  14. Amino acid intake during lactation and amino acids of plasma and human milk.

    PubMed

    Ramirez, I; DeSantiago, S; Tovar, A R; Torres, N

    2001-01-01

    The aim of this study was to determine the free amino acid pool in plasma and milk in marginally nourished lactating women. Twenty-eight rural women (age, 23.9+/-5y; weight 50.2+/-4.9 kg; height, 148.2+/-4.8 cm) were studied under metabolic balance conditions. Subjects were divided into 6 groups (5-6 women in each), representing rural mothers postweaning and in the 15, 3rd, and 6th months of lactation; nonpregnant, nonlactating controls were from rural and urban areas. Amino acid analyses of diet and of plasma and milk samples were performed using a Beckman 6300 amino acid analyzer. Lysine intakes were lower than the recommended intake for lactating women (RDA). Plasma amino acid profiles differed between the lactating and weaned groups: aspartate and isoleucine increased at the 6th month (P < 0.05), while valine declined over weaning time (P < 0.05). In milk, valine and proline decreased at the 6th month (P < 0.05), while serine rose at the 3rd month. Free amino acid pools were 1- to 15-fold higher in plasma than in milk for branched-chain amino acids and basic, aromatic, and neutral amino acids. In mammary tissue these amino acids can be channeled to tissue and milk protein synthesis or to catabolic pathways. Glutamate was 40-fold higher in milk with respect to plasma content. This was the predominant amino acid in the free amino acid pool in milk. These results suggest selective amino acid transport in mammary tissue during lactation.

  15. Amino acids in the Yamato carbonaceous chrondrite from Antarctica

    NASA Technical Reports Server (NTRS)

    Shimoyama, A.; Ponnamperuma, C.; Yanai, K.

    1979-01-01

    Evidence for the presence of amino acids of extraterrestrial origin in the Antarctic Yamato carbonaceous chrondrite is presented. Hydrolyzed and nonhydrolyzed water-extracted amino acid samples from exterior, middle and interior portions of the meteorite were analyzed by an amino acid analyzer and by gas chromatography of N-TFA-isopropyl amino acid derivatives. Nine protein and six nonprotein amino acids were detected in the meteorite at abundances between 34 and less than one nmole/g, with equal amounts in interior and exterior portions. Nearly equal abundances of the D and L enantiomers of alanine, aspartic acid and glutamic acid were found, indicating the abiotic, therefore extraterrestrial, origin of the amino acids. The Antarctic environment and the uniformity of protein amino acid abundances are discussed as evidence against the racemization of terrestrially acquired amino acids, and similarities between Yamato amino acid compositions and the amino acid compositions of the Murchison and Murray type II carbonaceous chrondrites are indicated.

  16. [Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

    PubMed

    Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

    1982-01-01

    The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

  17. Detection of non-protein amino acids in the presence of protein amino acids. II.

    NASA Technical Reports Server (NTRS)

    Shapshak, P.; Okaji, M.

    1972-01-01

    Studies conducted with the JEOL 5AH amino acid analyzer are described. This instrument makes possible the programming of the chromatographic process. Data are presented showing the separations of seventeen non-protein amino acids in the presence of eighteen protein amino acids. It is pointed out that distinct separations could be obtained in the case of a number of chemically similar compounds, such as ornithine and lysine, N-amidino alanine and arginine, and iminodiacetic acid and S-carboxymethyl cysteine and aspartic acid.

  18. Biodegradable polymers derived from amino acids.

    PubMed

    Khan, Wahid; Muthupandian, Saravanan; Farah, Shady; Kumar, Neeraj; Domb, Abraham J

    2011-12-08

    In the past three decades, the use of polymeric materials has increased dramatically for biomedical applications. Many α-amino acids derived biodegradable polymers have also been intensely developed with the main goal to obtain bio-mimicking functional biomaterials. Polymers derived from α-amino acids may offer many advantages, as these polymers: (a) can be modified further to introduce new functions such as imaging, molecular targeting and drugs can be conjugated chemically to these polymers, (b) can improve on better biological properties like cell migration, adhesion and biodegradability, (c) can improve on mechanical and thermal properties and (d) their degradation products are expected to be non-toxic and readily metabolized/excreted from the body. This manuscript focuses on biodegradable polymers derived from natural amino acids, their synthesis, biocompatibility and biomedical applications. It is observed that polymers derived from α-amino acids constitute a promising family of biodegradable materials. These provide innovative multifunctional polymers possessing amino acid side groups with biological activity and with innumerous potential applications.

  19. Distinguishing Proteins From Arbitrary Amino Acid Sequences

    PubMed Central

    Yau, Stephen S.-T.; Mao, Wei-Guang; Benson, Max; He, Rong Lucy

    2015-01-01

    What kinds of amino acid sequences could possibly be protein sequences? From all existing databases that we can find, known proteins are only a small fraction of all possible combinations of amino acids. Beginning with Sanger's first detailed determination of a protein sequence in 1952, previous studies have focused on describing the structure of existing protein sequences in order to construct the protein universe. No one, however, has developed a criteria for determining whether an arbitrary amino acid sequence can be a protein. Here we show that when the collection of arbitrary amino acid sequences is viewed in an appropriate geometric context, the protein sequences cluster together. This leads to a new computational test, described here, that has proved to be remarkably accurate at determining whether an arbitrary amino acid sequence can be a protein. Even more, if the results of this test indicate that the sequence can be a protein, and it is indeed a protein sequence, then its identity as a protein sequence is uniquely defined. We anticipate our computational test will be useful for those who are attempting to complete the job of discovering all proteins, or constructing the protein universe. PMID:25609314

  20. Amino acid pools in cultured muscle cells.

    PubMed

    Low, R B; Stirewalt, W S; Rittling, S R; Woodworth, R C

    1984-01-01

    Compartmentalization of cellular amino acid pools occurs in cultures of cardiac and skeletal muscle cells, but the factors involved in this are not clear. We have further defined this problem by analyzing the intracellular free leucine and the transfer-RNA-(tRNA)-bound leucine pool in cultures of skeletal and cardiac muscle incubated with 3H-leucine in the presence and absence of serum and amino acids. Withdrawal of nitrogen substrates caused substantial changes in leucine pool relationships--in particular, a change in the degree to which intracellular free leucine and tRNA-leucine were derived from the culture medium. In separate experiments, the validity of our tRNA measurements was confirmed by measurements of the specific activity of newly synthesized ferritin after iron induction. We discuss the implications of these findings with regard to factors involved in the control of amino acid flux through the cell, as well as with regard to design of experiments using isotopic amino acids to measure rates of amino acid utilization.

  1. Conformations of amino acids in proteins.

    PubMed

    Hovmöller, Sven; Zhou, Tuping; Ohlson, Tomas

    2002-05-01

    The main-chain conformations of 237 384 amino acids in 1042 protein subunits from the PDB were analyzed with Ramachandran plots. The populated areas of the empirical Ramachandran plot differed markedly from the classical plot in all regions. All amino acids in alpha-helices are found within a very narrow range of phi, psi angles. As many as 40% of all amino acids are found in this most populated region, covering only 2% of the Ramachandran plot. The beta-sheet region is clearly subdivided into two distinct regions. These do not arise from the parallel and antiparallel beta-strands, which have quite similar conformations. One beta region is mainly from amino acids in random coil. The third and smallest populated area of the Ramachandran plot, often denoted left-handed alpha-helix, has a different position than that originally suggested by Ramachandran. Each of the 20 amino acids has its own very characteristic Ramachandran plot. Most of the glycines have conformations that were considered to be less favoured. These results may be useful for checking secondary-structure assignments in the PDB and for predicting protein folding.

  2. Amino acid uptake in rust fungi

    PubMed Central

    Struck, Christine

    2015-01-01

    The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia, or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid transporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways. PMID:25699068

  3. Amino acid uptake in rust fungi.

    PubMed

    Struck, Christine

    2015-01-01

    The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia, or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid transporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways.

  4. Amino Acids Profiles in Biological Media

    SciTech Connect

    Iordache, A.; Horj, E.; Morar, S.; Cozar, O.; Culea, M.; Ani, A. R.; Mesaros, C.

    2010-08-04

    An accurate analytical method was developed to determine amino acids in some biological specimens by GC/MS technique. Stable isotopes provide useful tools for a variety of studies, offering ideal internal standards in quantitative information. Isotopic dilution gas chromatography--mass spectrometry (ID-GC/MS) is the techniques used for quantitative analysis of compounds labeled with stable isotopes. A Trace DSQ Thermo Finnigan quadrupole mass spectrometer coupled with a Trace GC was used. Amino acids were separated on a Rtx-5 MS capillary column, 30 mx0.25 mm, 0.25 {mu}m film thickness, using a temperature program from 50 deg. C, 1 min, 6 deg. C/min at 100 deg. C, 4 deg. C/min at 200 deg. C, 20 deg. C/min at 300 deg. C, (3 min). The transfer line temperature was 250 deg. C, the injector temperature 200 deg. C and ion source temperature 250 deg. C; splitter: 10:1. Electron energy was 70 eV and emission current, 100 {mu}A. The amino acids were purified on a Dowex 50W-W8 exchange resin and were derivatized in a procedure following two steps to obtain trifluoroacetyl butyl esters. The identification of amino acids was obtained by using NIST library but also by using amino acid standards.

  5. Active Uptake of Amino Acids by Leaves of an Epiphytic Vascular Plant, Tillandsia paucifolia (Bromeliaceae) 1

    PubMed Central

    Nyman, Leslie Paul; Davis, James P.; O'Dell, Stephen J.; Arditti, Joseph; Stephens, Grover C.; Benzing, David H.

    1987-01-01

    Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 104. Images Fig. 2 Fig. 3 PMID:16665307

  6. Amino acid "little Big Bang": representing amino acid substitution matrices as dot products of Euclidian vectors.

    PubMed

    Zimmermann, Karel; Gibrat, Jean-François

    2010-01-04

    Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms.

  7. Amino acids of the Murchison meteorite. III - Seven carbon acyclic primary alpha-amino alkanoic acids

    NASA Technical Reports Server (NTRS)

    Cronin, John R.; Pizzarello, Sandra

    1986-01-01

    All of the eighteen possible seven-carbon acyclic primary alpha-amino alkanoic acids have been positively identified in a hot-water extract of the Murchison meteorite by the combined use of gas chromatography-mass spectrometry, ion exchange chromatography and reversed-phase chromatography. None of these amino acids has previously been found in meteorites or in any other natural material. They range in concentration from less than or equal to 0.5 to 5.3 nmol/g. Configuration assignments were made for 2-amino-3,4-dimethylpentanoic acid and allo-2-amino-3,4-dimethylpentanoic acid and the diasteromer ratio was determined. Fifty-five amino acids have now been positively identified in the Murchison meteorite, 36 of which are unknown in terrestrial materials. This unique suite of amino acids is characterized by the occurrence of all structural isomers within the two major classes of amino acids represented, by the predominance of branched chain isomers, and by an exponential decline in amount with increasing carbon chain length within homologous series. These characteristics of the Murchison amino acids are suggestive of synthesis before incorporation into a parent body.

  8. Amino acid "little Big Bang": Representing amino acid substitution matrices as dot products of Euclidian vectors

    PubMed Central

    2010-01-01

    Background Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. Results We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. Conclusions This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms. PMID:20047649

  9. The metabolism of "surplus" amino acids.

    PubMed

    Bender, David A

    2012-08-01

    For an adult in N balance, apart from small amounts of amino acids required for the synthesis of neurotransmitters, hormones, etc, an amount of amino acids almost equal to that absorbed from the diet can be considered to be "surplus" in that it will be catabolized. The higher diet-induced thermogenesis from protein than from carbohydrate or fat has generally been assumed to be due to increased protein synthesis, which is ATP expensive. To this must be added the ATP cost of protein catabolism through the ubiquitin-proteasome pathway. Amino acid catabolism will add to thermogenesis. Deamination results in net ATP formation except when serine and threonine deaminases are used, but there is the energy cost of synthesizing glutamine in extra-hepatic tissues. The synthesis of urea has a net cost of only 1·5 × ATP when the ATP yield from fumarate metabolism is offset against the ATP cost of the urea cycle, but this offset is thermogenic. In fasting and on a low carbohydrate diet as much of the amino acid carbon as possible will be used for gluconeogenesis - an ATP-expensive, and hence thermogenic, process. Complete oxidation of most amino acid carbon skeletons also involves a number of thermogenic steps in which ATP (or GTP) or reduced coenzymes are utilized. There are no such thermogenic steps in the metabolism of pyruvate, acetyl CoA or acetoacetate, but for amino acids that are metabolized by way of the citric acid cycle intermediates there is thermogenesis ranging from 1 up to 7 × ATP equivalent per mol.

  10. Temperature dependence of amino acid hydrophobicities.

    PubMed

    Wolfenden, Richard; Lewis, Charles A; Yuan, Yang; Carter, Charles W

    2015-06-16

    The hydrophobicities of the 20 common amino acids are reflected in their tendencies to appear in interior positions in globular proteins and in deeply buried positions of membrane proteins. To determine whether these relationships might also have been valid in the warm surroundings where life may have originated, we examined the effect of temperature on the hydrophobicities of the amino acids as measured by the equilibrium constants for transfer of their side-chains from neutral solution to cyclohexane (K(w > c)). The hydrophobicities of most amino acids were found to increase with increasing temperature. Because that effect is more pronounced for the more polar amino acids, the numerical range of K(w > c) values decreases with increasing temperature. There are also modest changes in the ordering of the more polar amino acids. However, those changes are such that they would have tended to minimize the otherwise disruptive effects of a changing thermal environment on the evolution of protein structure. Earlier, the genetic code was found to be organized in such a way that--with a single exception (threonine)--the side-chain dichotomy polar/nonpolar matches the nucleic acid base dichotomy purine/pyrimidine at the second position of each coding triplet at 25 °C. That dichotomy is preserved at 100 °C. The accessible surface areas of amino acid side-chains in folded proteins are moderately correlated with hydrophobicity, but when free energies of vapor-to-cyclohexane transfer (corresponding to size) are taken into consideration, a closer relationship becomes apparent.

  11. Economic aspects of amino acids production.

    PubMed

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  12. Amino acid composition of human milk is not unique.

    PubMed

    Davis, T A; Nguyen, H V; Garcia-Bravo, R; Fiorotto, M L; Jackson, E M; Lewis, D S; Lee, D R; Reeds, P J

    1994-07-01

    To determine whether the amino acid pattern of human milk is unique, we compared the amino acid pattern of human milk with the amino acid patterns of the milks of great apes (chimpanzee and gorilla), lower primates (baboon and rhesus monkey) and nonprimates (cow, goat, sheep, llama, pig, horse, elephant, cat and rat). Amino acid pattern was defined as the relative proportion of each amino acid (protein-bound plus free) (in mg) to the total amino acids (in g). Total amino acid concentration was lower in primate milk than in nonprimate milk. There were commonalities in the overall amino acid pattern of the milks of all species sampled; the most abundant amino acids were glutamate (plus glutamine, 20%), proline (10%) and leucine (10%). Essential amino acids were 40%, branched-chain amino acids 20%, and sulfur amino acids 4% of the total amino acids. The amino acid pattern of human milk was more similar to those of great apes than to those of lower primates. For example, cystine was higher and methionine was lower in primate milks than in nonprimate milks, and in great ape and human milks than in lower primate milks. Because the milk amino acid patterns of the human and elephant, both slow-growing species, were dissimilar, the amino acid pattern of human milk seems unrelated to growth rate.

  13. L-amino acid oxidases with specificity for basic L-amino acids in cyanobacteria.

    PubMed

    Gau, Achim E; Heindl, Achim; Nodop, Anke; Kahmann, Uwe; Pistorius, Elfriede K

    2007-01-01

    The two closely related fresh water cyanobacteria Synechococcus elongatus PCC 6301 and Synechococcus elongatus PCC 7942 have previously been shown to constitutively express a FAD-containing L-amino acid oxidase with high specificity for basic L-amino acids (L-arginine being the best substrate). In this paper we show that such an enzyme is also present in the fresh water cyanobacterium Synechococcus cedrorum PCC 6908. In addition, an improved evaluation of the nucleotide/amino acid sequence of the L-amino acid oxidase of Synechococcus elongatus PCC 6301 (encoded by the aoxA gene) with respect to the FAD-binding site and a translocation pathway signal sequence will be given. Moreover, the genome sequences of 24 cyanobacteria will be evaluated for the occurrence of an aoxA-similar gene. In the evaluated cyanobacteria 15 genes encoding an L-amino acid oxidase-similar protein will be found.

  14. Glutamate: a truly functional amino acid.

    PubMed

    Brosnan, John T; Brosnan, Margaret E

    2013-09-01

    Glutamate is one of the most abundant of the amino acids. In addition to its role in protein structure, it plays critical roles in nutrition, metabolism and signaling. Post-translational carboxylation of glutamyl residues increases their affinity for calcium and plays a major role in hemostasis. Glutamate is of fundamental importance to amino acid metabolism, yet the great bulk of dietary glutamate is catabolyzed within the intestine. It is necessary for the synthesis of key molecules, such as glutathione and the polyglutamated folate cofactors. It plays a major role in signaling. Within the central nervous system, glutamate is the major excitatory neurotransmitter and its product, GABA, the major inhibitory neurotransmitter. Glutamate interaction with specific taste cells in the tongue is a major component of umami taste. The finding of glutamate receptors throughout the gastrointestinal tract has opened up a new vista in glutamate function. Glutamate is truly a functional amino acid.

  15. Cometary Amino Acids from the STARDUST Mission

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elsila

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81 P/WiId 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a cometary amino acid.

  16. Cometary Amino Acids from the STARDUST Mission

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elsila

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81 P/WiId 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a cometary amino acid.

  17. Amino Acid and Protein Metabolism in Bermuda Grass During Water Stress 12

    PubMed Central

    Barnett, N. M.; Naylor, A. W.

    1966-01-01

    The ability of Arizona Common and Coastal Bermuda grass [Cynodon dactylon (L.) Pers.] to synthesize amino acids and proteins during water stress was investigated. Amino acids were continually synthesized during the water stress treatments, but protein synthesis was inhibited and protein levels decreased. Water stress induced a 10- to 100-fold accumulation of free proline in shoots and a 2- to 6-fold accumulation of free asparagine, both of which are characteristic responses of water-stressed plants. Valine levels increased, and glutamic acid and alanine levels decreased. 14C labeling experiments showed that free proline turns over more slowly than any other free amino acid during water stress. This proline is readily synthesized and accumulated from glutamic acid. It is suggested that during water stress free proline functions as a storage compound. No significant differences were found in the amino acid and protein metabolism of the 2 varieties of Bermuda grass. PMID:16656387

  18. Inhibited muscle amino acid uptake in sepsis.

    PubMed Central

    Hasselgren, P O; James, J H; Fischer, J E

    1986-01-01

    Amino acid uptake in vivo was determined in soleus (SOL) muscle, diaphragm, heart, and liver following intravenous injection of [3H]-alpha-amino-isobutyric acid ([3H]-AIB) in rats made septic by cecal ligation and puncture (CLP) and in sham-operated controls. Muscle amino acid transport was also measured in vitro by determining uptake of [3H]-AIB in incubated extensor digitorum longus (EDL) and SOL muscles. Results were expressed as distribution ratio between [3H]-AIB in intracellular and extracellular fluid. AIB uptake in vivo was reduced by 90% in SOL and cardiac muscle and by 45% in diaphragm 16 hours after CLP. In contrast, AIB uptake by liver was almost four times higher in septic than in control animals. AIB uptake in vitro was reduced by 18% in EDL 8 hours after CLP but was not significantly altered in SOL at the same time point. Sixteen hours after CLP, AIB uptake was significantly reduced in both muscles, i.e., by 17% in EDL and by 65% in SOL. When muscles from untreated rats were incubated in the presence of plasma from septic animals (16 hours CLP) or from animals injected with endotoxin (2 mg/kg body weight), AIB uptake was reduced. Addition of endotoxin in vitro (2-200 micrograms/ml) to incubated muscles did not affect AIB uptake. The results suggest that sepsis leads to marked impairment of amino acid transport system A in muscle and that this impairment is mediated by a circulating factor that is not endotoxin. Reduced uptake of amino acids by skeletal muscle during sepsis may divert amino acids to the liver for increased gluconeogenesis and protein synthesis. PMID:3963895

  19. Microbial degradation of poly(amino acid)s.

    PubMed

    Obst, Martin; Steinbüchel, Alexander

    2004-01-01

    Natural poly(amino acid)s are a group of poly(ionic) molecules (ionomers) with various biological functions and putative technical applications and play, therefore, an important role both in nature and in human life. Because of their biocompatibility and their synthesis from renewable resources, poly(amino acid)s may be employed for many different purposes covering a broad spectrum of medical, pharmaceutical, and personal care applications as well as the domains of agriculture and of environmental applications. Biodegradability is one important advantage of naturally occurring poly(amino acid)s over many synthetic polymers. The intention of this review is to give an overview about the enzyme systems catalyzing the initial steps in poly(amino acid) degradation. The focus is on the naturally occurring poly(amino acid)s cyanophycin, poly(epsilon-L-lysine) and poly(gamma-glutamic acid); but biodegradation of structurally related synthetic polyamides such as poly(aspartic acid) and nylons, which are known from various technical applications, is also included.

  20. Amino acid nutrition of fishes: requirements and supplementation of diets

    USGS Publications Warehouse

    Ketola, H.G.

    1982-01-01

    The purpose of this paper is: (1) to make a concise review of the published dietary requirements of fishes for amino acids, (2) to describe recent findings at the Tunison Laboratory concerning amino acid nutrition of trout, (3) to review specific signs of deficiency of amino acids, and (4) to discuss use of the fish egg amino acid pattern as a guideline to formulating new feeds or studying amino acid requirements of fishes for which there is limited information on their quantitative requirements.

  1. Experimental evolution of a green fluorescent protein composed of 19 unique amino acids without tryptophan.

    PubMed

    Kawahara-Kobayashi, Akio; Hitotsuyanagi, Mitsuhiro; Amikura, Kazuaki; Kiga, Daisuke

    2014-04-01

    At some stage of evolution, genes of organisms may have encoded proteins that were synthesized using fewer than 20 unique amino acids. Similar to evolution of the natural 19-amino-acid proteins GroEL/ES, proteins composed of 19 unique amino acids would have been able to evolve by accumulating beneficial mutations within the 19-amino-acid repertoire encoded in an ancestral genetic code. Because Trp is thought to be the last amino acid included in the canonical 20-amino-acid repertoire, this late stage of protein evolution could be mimicked by experimental evolution of 19-amino-acid proteins without tryptophan (Trp). To further understand the evolution of proteins, we tried to mimic the evolution of a 19-amino-acid protein involving the accumulation of beneficial mutations using directed evolution by random mutagenesis on the whole targeted gene sequence. We created active 19-amino-acid green fluorescent proteins (GFPs) without Trp from a poorly fluorescent 19-amino-acid mutant, S1-W57F, by using directed evolution with two rounds of mutagenesis and selection. The N105I and S205T mutations showed beneficial effects on the S1-W57F mutant. When these two mutations were combined on S1-W57F, we observed an additive effect on the fluorescence intensity. In contrast, these mutations showed no clear improvement individually or in combination on GFPS1, which is the parental GFP mutant composed of 20 amino acids. Our results provide an additional example for the experimental evolution of 19-amino-acid proteins without Trp, and would help understand the mechanisms underlying the evolution of 19-amino-acid proteins. (236 words).

  2. Experimental Evolution of a Green Fluorescent Protein Composed of 19 Unique Amino Acids without Tryptophan

    NASA Astrophysics Data System (ADS)

    Kawahara-Kobayashi, Akio; Hitotsuyanagi, Mitsuhiro; Amikura, Kazuaki; Kiga, Daisuke

    2014-04-01

    At some stage of evolution, genes of organisms may have encoded proteins that were synthesized using fewer than 20 unique amino acids. Similar to evolution of the natural 19-amino-acid proteins GroEL/ES, proteins composed of 19 unique amino acids would have been able to evolve by accumulating beneficial mutations within the 19-amino-acid repertoire encoded in an ancestral genetic code. Because Trp is thought to be the last amino acid included in the canonical 20-amino-acid repertoire, this late stage of protein evolution could be mimicked by experimental evolution of 19-amino-acid proteins without tryptophan (Trp). To further understand the evolution of proteins, we tried to mimic the evolution of a 19-amino-acid protein involving the accumulation of beneficial mutations using directed evolution by random mutagenesis on the whole targeted gene sequence. We created active 19-amino-acid green fluorescent proteins (GFPs) without Trp from a poorly fluorescent 19-amino-acid mutant, S1-W57F, by using directed evolution with two rounds of mutagenesis and selection. The N105I and S205T mutations showed beneficial effects on the S1-W57F mutant. When these two mutations were combined on S1-W57F, we observed an additive effect on the fluorescence intensity. In contrast, these mutations showed no clear improvement individually or in combination on GFPS1, which is the parental GFP mutant composed of 20 amino acids. Our results provide an additional example for the experimental evolution of 19-amino-acid proteins without Trp, and would help understand the mechanisms underlying the evolution of 19-amino-acid proteins. (236 words)

  3. Amino acid homeostasis and signalling in mammalian cells and organisms

    PubMed Central

    Bröer, Angelika

    2017-01-01

    Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake. PMID:28546457

  4. Pipecolic acid enhances resistance to bacterial infection and primes salicylic acid and nicotine accumulation in tobacco

    PubMed Central

    Vogel-Adghough, Drissia; Stahl, Elia; Návarová, Hana; Zeier, Jürgen

    2013-01-01

    Distinct amino acid metabolic pathways constitute integral parts of the plant immune system. We have recently identified pipecolic acid (Pip), a lysine-derived non-protein amino acid, as a critical regulator of systemic acquired resistance (SAR) and basal immunity to bacterial infection in Arabidopsis thaliana. In Arabidopsis, Pip acts as an endogenous mediator of defense amplification and priming. For instance, Pip conditions plants for effective biosynthesis of the phenolic defense signal salicylic acid (SA), accumulation of the phytoalexin camalexin, and expression of defense-related genes. Here, we show that tobacco plants respond to leaf infection by the compatible bacterial pathogen Pseudomonas syringae pv tabaci (Pstb) with a significant accumulation of several amino acids, including Lys, branched-chain, aromatic, and amide group amino acids. Moreover, Pstb strongly triggers, alongside the biosynthesis of SA and increases in the defensive alkaloid nicotine, the production of the Lys catabolites Pip and α-aminoadipic acid. Exogenous application of Pip to tobacco plants provides significant protection to infection by adapted Pstb or by non-adapted, hypersensitive cell death-inducing P. syringae pv maculicola. Pip thereby primes tobacco for rapid and strong accumulation of SA and nicotine following bacterial infection. Thus, our study indicates that the role of Pip as an amplifier of immune responses is conserved between members of the rosid and asterid groups of eudicot plants and suggests a broad practical applicability for Pip as a natural enhancer of plant disease resistance. PMID:24025239

  5. Pipecolic acid enhances resistance to bacterial infection and primes salicylic acid and nicotine accumulation in tobacco.

    PubMed

    Vogel-Adghough, Drissia; Stahl, Elia; Návarová, Hana; Zeier, Juergen

    2013-11-01

    Distinct amino acid metabolic pathways constitute integral parts of the plant immune system. We have recently identified pipecolic acid (Pip), a lysine-derived non-protein amino acid, as a critical regulator of systemic acquired resistance (SAR) and basal immunity to bacterial infection in Arabidopsis thaliana. In Arabidopsis, Pip acts as an endogenous mediator of defense amplification and priming. For instance, Pip conditions plants for effective biosynthesis of the phenolic defense signal salicylic acid (SA), accumulation of the phytoalexin camalexin, and expression of defense-related genes. Here, we show that tobacco plants respond to leaf infection by the compatible bacterial pathogen Pseudomonas syringae pv tabaci (Pstb) with a significant accumulation of several amino acids, including Lys, branched-chain, aromatic, and amide group amino acids. Moreover, Pstb strongly triggers, alongside the biosynthesis of SA and increases in the defensive alkaloid nicotine, the production of the Lys catabolites Pip and α-aminoadipic acid. Exogenous application of Pip to tobacco plants provides significant protection to infection by adapted Pstb or by non-adapted, hypersensitive cell death-inducing P. syringae pv maculicola. Pip thereby primes tobacco for rapid and strong accumulation of SA and nicotine following bacterial infection. Thus, our study indicates that the role of Pip as an amplifier of immune responses is conserved between members of the rosid and asterid groups of eudicot plants and suggests a broad practical applicability for Pip as a natural enhancer of plant disease resistance.

  6. Rapid Degradation of Auxin/Indoleacetic Acid Proteins Requires Conserved Amino Acids of Domain II and Is Proteasome Dependent

    PubMed Central

    Ramos, Jason A.; Zenser, Nathan; Leyser, Ottoline; Callis, Judy

    2001-01-01

    Auxin rapidly induces auxin/indoleacetic acid (Aux/IAA) transcription. The proteins encoded are short-lived nucleus-localized transcriptional regulators that share four conserved domains. In a transient assay measuring protein accumulation, an Aux/IAA 13–amino acid domain II consensus sequence was sufficient to target firefly luciferase (LUC) for low protein accumulation equivalent to that observed previously for full-length PSIAA6. Single amino acid substitutions in these 13 amino acids, corresponding to known auxin response mutants, resulted in a sixfold to 20-fold increase in protein accumulation. Naturally occurring variant amino acids had no effect. Residues identified as essential by single alanine substitutions were not sufficient when all flanking amino acids were alanine, indicating the importance of flanking regions. Using direct protein degradation measurements in transgenic Arabidopsis seedlings, full-length IAA1, PSIAA6, and the N-terminal 73 PSIAA6 amino acids targeted LUC for rapid degradation with 8-min half-lives. The C-terminal 109 amino acids did not affect LUC half-life. Smaller regions containing domain II also targeted LUC for rapid degradation, but the rates were not equivalent to those of the full-length protein. A single domain II substitution in the context of full-length PSIAA6 increased half-life 30-fold. Proteasome inhibitors affected Aux/IAA::LUC fusion protein accumulation, demonstrating the involvement of the proteasome. PMID:11595806

  7. Polymerization of amino acids containing nucleotide bases

    NASA Technical Reports Server (NTRS)

    Ben Cheikh, Azzouz; Orgel, Leslie E.

    1990-01-01

    The nucleoamino acids 1-(3'-amino,3'-carboxypropyl)uracil (3) and 9-(3'-amino,3'-carboxypropyl)adenine (4) have been prepared as (L)-en-antiomers and as racemic mixtures. When 3 or 4 is suspended in water and treated with N,N'-carbon-yldiimidazole, peptides are formed in good yield. The products formed from the (L)-enantiomers are hydrolyzed to the monomeric amino acids by pronase. Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (L)-enantiomer of 3 did not act as templates to facilitate the oligomerization of 4.

  8. Porcine proinsulin: characterization and amino acid sequence.

    PubMed

    Chance, R E; Ellis, R M; Bromer, W W

    1968-07-12

    Proinsulin in nearly homogeneous form has been isolated from a preparation of porcine insulin. A molecular weight close to 9100 was calculated from the amino acid composition and from sedimentation-equilibrium studies. Through the action of trypsin this single-chain protein is transformed to desalanine insulin by cleavage of a polypeptide chain connecting the carboxy-terminus of the B chain to the amino-terminus of the A chain of insulin. The amino acid sequence of this connecting peptide was found to be Arg-Arg-Glu-Ala-Gln-Asn-Pro-Gln-Ala-Gly-Ala-Val-Glu-Leu-Gly-Gly-Gly-Leu-Gly-Gly-Leu-Gln-Ala-Leu-Ala-Leu-Glu-Gly-Pro-Pro-Gln-Lys-Arg.

  9. Polymerization of amino acids containing nucleotide bases

    NASA Technical Reports Server (NTRS)

    Ben Cheikh, Azzouz; Orgel, Leslie E.

    1990-01-01

    The nucleoamino acids 1-(3'-amino,3'-carboxypropyl)uracil (3) and 9-(3'-amino,3'-carboxypropyl)adenine (4) have been prepared as (L)-en-antiomers and as racemic mixtures. When 3 or 4 is suspended in water and treated with N,N'-carbon-yldiimidazole, peptides are formed in good yield. The products formed from the (L)-enantiomers are hydrolyzed to the monomeric amino acids by pronase. Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (L)-enantiomer of 3 did not act as templates to facilitate the oligomerization of 4.

  10. Utilization of amino acids and dipeptides by Lactobacillus plantarum from orange in nutritionally stressed conditions.

    PubMed

    Saguir, F M; Loto Campos, I E; Manca de Nadra, M C

    2008-06-01

    To investigate amino acid and dipeptide utilization by Lactobacillus plantarum N4 isolated from orange peel, in a nutritionally depleted medium based on MRS (Mann, Rogosa, Sharpe). In MRS with 0.1 g l(-1) of meat extract and without peptone and yeast extract, growth increased when essential and stimulatory amino acids and nonessential amino acid were added to the medium. Replacement of the essential amino acid, leucine, and the nonessential amino acid, glycine, by leucyl-leucine (Leu-Leu) and/or glycyl-glycine (Gly-Gly) significantly enhanced growth. Essential amino acids were mainly consumed and the dipeptides were almost completely used at the end of growth. Leucine and glycine accumulated internally from the peptides were higher than from the free amino acids. Glucose utilization increased in the media containing dipeptides compared with the medium containing free amino acids. In a N-depleted medium, Leu-Leu and/or Gly-Gly were more effective than the respective amino acids in supporting growth of the micro-organism. The more efficient internal accumulation of glycine and especially leucine from dipeptides confirmed the ability of the strain to assimilate mainly complex nitrogen molecules rather than simple ones. The ability of Lact. plantarum N4 to efficiently use dipeptides could contribute to spoilage development in the natural medium of the organism, orange juice.

  11. Intestinal metabolism of sulfur amino acids

    USDA-ARS?s Scientific Manuscript database

    The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acid (SAA) metabolism in the body and metabolizes approx. 20% of the dietary methionine intake that is mainly transmethylated to homocysteine and transsulfurated to cysteine. The GIT accounts for approx. 25% of the ...

  12. Amino Acid Formation on Interstellar Dust Particles

    NASA Astrophysics Data System (ADS)

    Meierhenrich, U. J.; Munoz Caro, G. M.; Barbier, B.; Brack, A.; Thiemann, W.; Goesmann, F.; Rosenbauer, H.

    2003-04-01

    In the dense interstellar medium dust particles accrete ice layers of known molecular composition. In the diffuse interstellar medium these ice layers are subjected to energetic UV-irradiation. Here, photoreactions form complex organic molecules. The interstellar processes were recently successfully simulated in two laboratories. At NASA Ames Research Center three amino acids were detected in interstellar ice analogues [1], contemporaneously, our European team reported on the identification of 16 amino acids therein [2]. Amino acids are the molecular building blocks of proteins in living organisms. The identification of amino acids on the simulated icy surface of interstellar dust particles strongly supports the assumption that the precursor molecules of life were delivered from interstellar and interplanetary space via (micro-) meteorites and/or comets to the earyl Earth. The results shall be verified by the COSAC experiment onboard the ESA cometary mission Rosetta [3]. [1] M.P. Bernstein, J.P. Dworkin, S.A. Sandford, G.W. Cooper, L.J. Allamandola: itshape Nature \\upshape 416 (2002), 401-403. [2] G.M. Muñoz Caro, U.J. Meierhenrich, W.A. Schutte, B. Barbier, A. Arcones Sergovia, H. Rosenbauer, W.H.-P. Thiemann, A. Brack, J.M. Greenberg: itshape Nature \\upshape 416 (2002), 403-406. [3] U. Meierhenrich, W.H.-P. Thiemann, H. Rosenbauer: itshape Chirality \\upshape 11 (1999), 575-582.

  13. Manganese alters rat brain amino acids levels

    PubMed Central

    Santos, Dinamene; Batoreu, M. Camila; Almeida, Isabel; Ramos, Ruben; Sidoryk-Wegrzynowicz, M.; Aschner, Michael; Marreilha dos Santos, A.P.

    2012-01-01

    Manganese (Mn) is an essential element and it acts as a cofactor for a number of enzymatic reactions, including those involved in amino acid, lipid, protein and carbohydrate metabolism. Excessive exposure to Mn can lead to poisoning, characterized by psychiatric disturbances and an extrapyramidal disorder. Mn-induced neuronal degeneration is associated with alterations in amino acids metabolism. In the present study, we analyzed whole rat brain amino acid content subsequent to 4 or 8 intraperitoneal (ip) injections, with 25 mg MnCl2/kg/day, at 48-hour (h) intervals. We noted a significant increase in glycine brain levels after 4 or 8 Mn injections (p<0.05 and p<0.01, respectively) and arginine also after 4 or 8 injections (p<0.001). Significant increases were also noted in brain proline (p<0.01), cysteine (p<0.05), phenylalanine (p<0.01) and tyrosine (p<0.01) levels after 8 Mn injections vs. the control group. These findings suggest that Mn-induced alterations in amino acid levels secondary to Mn affect the neurochemical milieu. PMID:22971893

  14. Human splanchnic amino-acid metabolism.

    PubMed

    Neis, Evelien P J G; Sabrkhany, S; Hundscheid, I; Schellekens, D; Lenaerts, K; Olde Damink, S W; Blaak, E E; Dejong, C H C; Rensen, Sander S

    2017-01-01

    Plasma levels of several amino acids are correlated with metabolic dysregulation in obesity and type 2 diabetes. To increase our understanding of human amino-acid metabolism, we aimed to determine splanchnic interorgan amino-acid handling. Twenty patients planned to undergo a pylorus preserving pancreatico-duodenectomy were included in this study. Blood was sampled from the portal vein, hepatic vein, superior mesenteric vein, inferior mesenteric vein, splenic vein, renal vein, and the radial artery during surgery. The difference between arterial and venous concentrations of 21 amino acids was determined using liquid chromatography as a measure of amino-acid metabolism across a given organ. Whereas glutamine was significantly taken up by the small intestine (121.0 ± 23.8 µmol/L; P < 0.0001), citrulline was released (-36.1 ± 4.6 µmol/L; P < 0.0001). This, however, was not seen for the colon. Interestingly, the liver showed a small, but a significant uptake of citrulline from the circulation (4.8 ± 1.6 µmol/L; P = 0.0138) next to many other amino acids. The kidneys showed a marked release of serine and alanine into the circulation (-58.0 ± 4.4 µmol/L and -61.8 ± 5.2 µmol/L, P < 0.0001), and a smaller, but statistically significant release of tyrosine (-12.0 ± 1.3 µmol/L, P < 0.0001). The spleen only released taurine (-9.6 ± 3.3 µmol/L; P = 0.0078). Simultaneous blood sampling in different veins provides unique qualitative and quantitative information on integrative amino-acid physiology, and reveals that the well-known intestinal glutamine-citrulline pathway appears to be functional in the small intestine but not in the colon.

  15. Nickel deficiency disrupts metabolism of ureides, amino acids, and organic acids of young pecan foliage.

    PubMed

    Bai, Cheng; Reilly, Charles C; Wood, Bruce W

    2006-02-01

    The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan.

  16. D-Amino Acids in Living Higher Organisms

    NASA Astrophysics Data System (ADS)

    Fujii, Noriko

    2002-04-01

    The homochirality of biological amino acids (L-amino acids) and of the RNA/DNA backbone (D-ribose) might have become established before the origin of life. It has been considered that D-amino acids and L-sugars were eliminated on the primitive Earth. Therefore, the presence and function of D-amino acids in living organisms have not been studied except for D-amino acids in the cell walls of microorganisms. However, D-amino acids were recently found in various living higher organisms in the form of free amino acids, peptides, and proteins. Free D-aspartate and D-serine are present and may have important physiological functions in mammals. D-amino acids in peptides are well known as opioid peptides and neuropeptides. In protein, D-aspartate residues increase during aging. This review deals with recent advances in the study of D-amino acids in higher organisms.

  17. Present Global Situation of Amino Acids in Industry.

    PubMed

    Tonouchi, Naoto; Ito, Hisao

    2016-11-11

    At present, amino acids are widely produced and utilized industrially. Initially, monosodium glutamate (MSG) was produced by extraction from a gluten hydrolysate. The amino acid industry started using the residual of the lysate. The discovery of the functions of amino acids has led to the expansion of their field of use. In addition to seasoning and other food use, amino acids are used in many fields such as animal nutrients, pharmaceuticals, and cosmetics. On the other hand, the invention of the glutamate fermentation process, followed by the development of fermentation methods for many other amino acids, is no less important. The supply of these amino acids at a low price is very essential for their industrial use. Most amino acids are now produced by fermentation. The consumption of many amino acids such as MSG or feed-use amino acids is still rapidly increasing.

  18. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl amino substituted triazine amino...

  19. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl amino substituted triazine amino...

  20. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl amino substituted triazine amino...

  1. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl amino substituted triazine amino...

  2. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl amino substituted triazine amino...

  3. How phosphoinositide 3-phosphate controls growth downstream of amino acids and autophagy downstream of amino acid withdrawal.

    PubMed

    Ktistakis, Nicholas T; Manifava, Maria; Schoenfelder, Priya; Rotondo, Sergio

    2012-02-01

    The simple phosphoinositide PtdIns3P has been shown to control cell growth downstream of amino acid signalling and autophagy downstream of amino acid withdrawal. These opposing effects depend in part on the existence of distinct complexes of Vps34 (vacuolar protein sorting 34), the kinase responsible for the majority of PtdIns3P synthesis in cells: one complex is activated after amino acid withdrawal to induce autophagy and another regulates mTORC1 (mammalian target of rapamycin complex 1) activation when amino acids are present. However, lipid-dependent signalling almost always exhibits a spatial dimension, related to the site of formation of the lipid signal. In the case of PtdIns3P-regulated autophagy induction, recent data suggest that PtdIns3P accumulates in a membrane compartment dynamically connected to the endoplasmic reticulum that constitutes a platform for the formation of some autophagosomes. For PtdIns3P-regulated mTORC1 activity, a spatial context is not yet known: several possibilities can be envisaged based on the known effects of PtdIns3P on the endocytic system and on recent data suggesting that activation of mTORC1 depends on its localization on lysosomes.

  4. [Secretion of endogenous amino acids in the gastrointestinal tract and amino acid resorption in the swine].

    PubMed

    Zebrowska, T; Simon, O; Münchmeyer, R; Bergner, H

    1976-02-01

    A trial was performed with 2 fistula pigs (each with 2 fistulas, one located about 30 cm below the pyloric orifice and the other at the end of the small intestine). Animal A received a casein diet containing 14% crude protein for a period of 2 weeks before the tracer amino acid was administered. Animal B received the same diet for a period of 10 days and was then fed a diet (at the same protein level) containing gluten as sole protein source. The two tracer amino acids, 14C-U-L-leucine and 3H-4,5-(N)-L-lysine, were injected intravenously. The passage rates for dry matter, organic matter and N measured at the beginning of the small intestine were higher than the rate of intake. The rate of passage of amino acids was also found to be increased relative to the rate of intake. In general, this increase involved the non-essential amino acids to a much larger extent. A considerable proportion of the amino acids passing into the large intestine is not excreted with the faeces but is probably converted in catabolic processes. It is for this reason that any values for the efficiency of amino acid absorption calculated on the basis of data on the faecal excretion of amino acids will not provide conclusive evidence for the availability of dietary amino acids in processes of the intermediate metabolism. The rate of secretion of 3H and 14C radioactivity into the digesta of the small intestine was found to increase rapidly within 1-2 hrs after administration of the tracer amino acids. The 14C radioactivity detected was found to be almost exclusively derived from 14C leucine while only about 60% of the 3H activity found in the digesta of fistula I were shown to be bound to lysine. Labelled lysine and leucine (of endogenic origin) are absorbed into the small intestine at a slower rate (i.e. endogenic proteins are less efficiently digested) than the non-radioactive amino acids (of exogenic origin) so that a process of concentration of endogenic amino acids is observed towards the

  5. Evolution from amino acids - Lunar occurrence of their precursors.

    NASA Technical Reports Server (NTRS)

    Fox, S. W.

    1972-01-01

    Review of the present state of experimentally based concepts of organic evolution from amino acids. Earlier studies of the synthesis of amino acid precursors from meteoritic material, lunar dust, and terrestrial lava are briefly summarized, and laboratory experiments in which polymers of amino acids were obtained either by direct heating of dry amino acids or by heating aqueous solutions of mixtures of amino acids are described. In particular, a process is described by which alpha-amino acids were made to react to form linear chains of proteinoids. It is concluded that a proteinoid microsystem was a common ancestor of all life on earth.

  6. Criteria for distinguishing biogenic and abiogenic amino acids - Preliminary considerations.

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1973-01-01

    Criteria to determine the mode of origin of amino acids can be established by consideration of their structure, enantiometric distribution, composition, and relative abundance. A population of dominantly protein amino acids with one enantiomeric configuration most likely had a biological origin. Biological amino acids do racemize, however, so the absence of optical activity would not rule out the possibility that the amino acids in a racemic mixture were originally synthesized biologically. For racemic amino acids, therefore, structure, composition and relative abundance become important in ascertaining the origin of these compounds. Abiotically synthesized amino acids have a population composed of both protein and nonprotein structures present as racemic mixtures.

  7. Permeability of membranes to amino acids and modified amino acids: mechanisms involved in translocation

    NASA Technical Reports Server (NTRS)

    Chakrabarti, A. C.; Deamer, D. W. (Principal Investigator); Miller, S. L. (Principal Investigator)

    1994-01-01

    The amino acid permeability of membranes is of interest because they are one of the key solutes involved in cell function. Membrane permeability coefficients (P) for amino acid classes, including neutral, polar, hydrophobic, and charged species, have been measured and compared using a variety of techniques. Decreasing lipid chain length increased permeability slightly (5-fold), while variations in pH had only minor effects on the permeability coefficients of the amino acids tested in liposomes. Increasing the membrane surface charge increased the permeability of amino acids of the opposite charge, while increasing the cholesterol content decreased membrane permeability. The permeability coefficients for most amino acids tested were surprisingly similar to those previously measured for monovalent cations such as sodium and potassium (approximately 10(-12)-10(-13) cm s-1). This observation suggests that the permeation rates for the neutral, polar and charged amino acids are controlled by bilayer fluctuations and transient defects, rather than partition coefficients and Born energy barriers. Hydrophobic amino acids were 10(2) more permeable than the hydrophilic forms, reflecting their increased partition coefficient values. External pH had dramatic effects on the permeation rates for the modified amino acid lysine methyl ester in response to transmembrane pH gradients. It was established that lysine methyl ester and other modified short peptides permeate rapidly (P = 10(-2) cm s-1) as neutral (deprotonated) molecules. It was also shown that charge distributions dramatically alter permeation rates for modified di-peptides. These results may relate to the movement of peptides through membranes during protein translocation and to the origin of cellular membrane transport on the early Earth.

  8. Some of the amino acid chemistry going on in the Laboratory of Amino Acids, Peptides and Proteins.

    PubMed

    Bouifraden, S; Drouot, C; el Hadrami, M; Guenoun, F; Lecointe, L; Mai, N; Paris, M; Pothion, C; Sadoune, M; Sauvagnat, B; Amblard, M; Aubagnac, J L; Calmes, M; Chevallet, P; Daunis, J; Enjalbal, C; Fehrentz, J A; Lamaty, F; Lavergne, J P; Lazaro, R; Rolland, V; Roumestant, M L; Viallefont, P; Vidal, Y; Martinez, J

    1999-01-01

    Some of the chemistry of amino acids going on in our laboratory (Laboratoire des Amino acides Peptides et Protéines) is described as well as some mass spectrometry methodology for their characterization particularly on solid supports. Several aspects are presented including: (i) the stereoselective synthesis of natural and unnatural amino acids using 2-hydroxypinan-3-one as chiral auxiliary; (ii) the stereoselective synthesis of natural and unnatural amino acids by deracemization of alpha-amino acids via their ketene derivatives; (iii) the synthesis of alpha-aryl-alpha-amino acids via reaction of organometallics with a glycine cation; (iv) the diastereoselective synthesis of glycosyl-alpha-amino acids; (v) the synthesis of beta-amino acids using alpha-aminopyrrolidinopiperazinediones as chiral templates; (vi) the reactivity of urethane-N-protected N-carboxyanhydrides. To characterize natural and non natural amino acids through their immonium ions by mass spectrometry, some methodology is also described.

  9. Amino acids regulate the intracellular trafficking of the general amino acid permease of Saccharomycescerevisiae.

    PubMed

    Chen, Esther J; Kaiser, Chris A

    2002-11-12

    The delivery to the plasma membrane of the general amino acid permease, Gap1p, of Saccharomyces cerevisiae is regulated by the quality of the nitrogen source in the growth medium. In an effort to define how different nitrogen sources control Gap1p sorting, we find that mutations in GDH1 and GLN1 that decrease the flux through the glutamate and glutamine synthesis pathways result in increased Gap1p sorting to the plasma membrane. Conversely, deletion of MKS1, which increases glutamate and glutamine synthesis, decreases Gap1p sorting to the plasma membrane. Glutamate and glutamine are not unusual in their ability to regulate Gap1p sorting, because the addition of all natural amino acids and many amino acid analogs to the growth medium results in increased Gap1p sorting to the vacuole. Importantly, amino acids have the capacity to signal Gap1p sorting to the vacuole regardless of whether they can be used as a source of nitrogen. Finally, we show that rapamycin does not affect Gap1p sorting, indicating that Gap1p sorting is not directly influenced by the TOR pathway. Together, these data show that amino acids are a signal for sorting Gap1p to the vacuole and imply that the nitrogen-regulated Gap1p sorting machinery responds to amino acid-like compounds rather than to the overall nutritional status associated with growth on a particular nitrogen source.

  10. Amino acids of the Murchison meteorite. I - Six carbon acyclic primary alpha-amino alkanoic acids

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Gandy, W. E.; Pizzarello, S.

    1981-01-01

    Six of the seven chain isomers of six-carbon acyclic primary alpha-amino alkanoic acids (leucine isomers) have been either identified or confirmed in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography. 2-Amino-2-ethylbutyric acid, 2-amino-2,3-dimethylbutyric acid, pseudoleucine, and 2-methylnorvaline were positively identified by GC-MS. These amino acids have not been previously reported to occur in natural materials and may be uniquely meteoritic in origin. The presence of leucine and isoleucine (including the diastereoisomer, alloisoleucine) was confirmed. Peaks corresponding to norleucine were seen by ion-exchange and gas chromatography but characteristic mass spectra were not obtained. The alpha-branched chain isomers in this series are quantitatively the most significant. These results are compared with literature data on amino acid synthesis by electrical discharge and Fischer-Tropsch-type catalysis. Neither model system produces an amino acid suite that is completely comparable to that found in the Murchison meteorite.

  11. Roles of phytochemicals in amino acid nutrition.

    PubMed

    Kong, Xiangfeng; Wu, Guoyao; Yin, Yinlong

    2011-01-01

    Chinese herbal medicine (CHM) is often used as dietary supplements to maintain good health in animals and humans. Here, we review the current knowledge about effects of CHM (including ultra-fine Chinese herbal powder, Acanthopanax senticosus extracts, Astragalus polysaccharide, and glycyrrhetinic acid) as dietary additives on physiological and biochemical parameters in pigs, chickens and rodents. Additionally, we propose possible mechanisms for the beneficial effects of CHM on the animals. These mechanisms include (a) increased digestion and absorption of dietary amino acids; (b) altered catabolism of amino acids in the small intestine and other tissues; (c) enhanced synthesis of functional amino acids (e.g., arginine, glutamine and proline) and polyamines; and (d) improved metabolic control of nutrient utilization through cell signaling. Notably, some phytochemicals and glucocorticoids share similarities in structure and physiological actions. New research findings provide a scientific and clinical basis for the use of CHM to improve well-being in livestock species and poultry, while enhancing the efficiency of protein accretion. Results obtained from animal studies also have important implications for human nutrition and health.

  12. Nonconventional techniques for separation of biosynthetic amino acids.

    PubMed

    Kloetzer, Lenuţa; Poştaru, Mădălina; Cheptea, Corina; Caşcaval, D; Galaction, Anca-Irina

    2014-01-01

    Amino acids can be obtained by biosynthesis, by protein hydrolysis or by extraction from natural sources. The most efficient methods are the first two, but the separation of amino acids from fermentation broths or protein hydrolysates is rather difficult. Amino acids dissociate in aqueous solutions, forming characteristic ionic species depending on the solution pH-value. These properties make amino acids to be hydrophilic at any pH-value. This paper presents a review of the separation studies of some amino acids by nonconventional methods, namely individual or selective reactive extraction. Separation of some amino acids from their mixture obtained either by fermentation or protein hydrolysis by reactive extraction with different extractants indicated the possibility of the amino acids selective separation as a function of the pH-value of aqueous solution correlated with the acidic or basic character of each amino acid.

  13. Fatty acid-amino acid conjugates diversification in Lepidopteran caterpillars

    USDA-ARS?s Scientific Manuscript database

    Fatty acid amino acid conjugates (FACs) have been found in Noctuid as well as Sphingid caterpillar oral secretions and especially volicitin [N-(17-hydroxylinolenoyl)-L-Glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants...

  14. AMINO ACID CROSS RESISTANCE IN AGROBACTERIUM TUMEFACIENS

    PubMed Central

    Beardsley, Robert E.

    1962-01-01

    Beardsley, Robert E. (Manhattan College, New York, N. Y.). Amino acid cross resistance in Agrobacterium tumefaciens. J. Bacteriol. 84:1237–1240. 1962.—Resistant clones selected on medium supplemented with glycine were also resistant to d-methionine, d-valine, dl-norleucine, and dl-serine. Cross resistance was similarly exhibited by clones selected on d-methionine, d-valine, or dl-norleucine. Two types of resistant organisms were observed. One produced colonies containing normal rods on selection medium. The other produced translucent colonies containing L forms. Both grew as typical rods in unsupplemented medium. Some resistant clones did not produce a temperate phage carried by the parental strain, but these retained immunity to homologous phage. The toxicity of d-methionine and d-valine for nonresistant bacteria is not reversed by the l isomers. The lethal effects of toxic amino acids are additive. PMID:13969951

  15. Ionic liquid crystals derived from amino acids.

    PubMed

    Mansueto, Markus; Frey, Wolfgang; Laschat, Sabine

    2013-11-18

    Novel chiral amino acid derived ionic liquid crystals with amine and amide moieties as spacers between the imidazolium head group and the alkyl chain were synthesised. The key step in the synthesis utilised the relatively uncommon SO3 leaving group in a microwave-assisted reaction. The mesomorphic properties of the mesogens were determined by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction. All liquid crystalline salts exhibit a smectic A mesophase geometry with strongly interdigitated bilayer structures. An increase of the steric bulk of the stereogenic centre hindered the formation of mesophases. In case of phenylalanine-derived derivatives a mesomorphic behaviour was observed for shorter alkyl chains as compared to other amino acid derivatives indicating an additional stabilising effect by the phenyl moiety.

  16. Amino Acid Enantiomeric Ratios in Biogeochemistry: Complications and Opportunities

    NASA Astrophysics Data System (ADS)

    McDonald, G. D.; Sun, H. J.; Tsapin, A. I.

    2003-12-01

    Amino acid enantiomeric ratios have been used for many years as an indicator of the process of racemization, and thus as a method to determine the age of biological samples such as bones, shells, and teeth. Dating biological samples by this method relies on an accurate knowledge of the environmental temperatures the sample has experienced, and the racemization kinetic parameters in the sample matrix. In some environments, where an independent dating method such as radiocarbon is available, the observed amino acid D/L ratios are found to be either higher or lower than those expected due to racemization alone. The observed D/L ratios in these cases can be clues to biogeochemical processes operating in addition to, or in place of, chemical racemization. In Siberian permafrost (Brinton et al. 2002, Astrobiology 2, 77) we have found D/L ratios lower than expected, which we have interpreted as evidence for low-level D-amino acid metabolism and recycling in microorganisms previously thought to be metabolically dormant. In microbially-colonized Antarctic Dry Valley sandstones (McDonald and Sun 2002, Eos Trans. AGU 83, Fall Meet. Suppl., Abstract B11A-0720) we have found D/L ratios higher than can be accounted for by racemization alone, most likely due to the accumulation of D-amino-acid-containing peptidoglycan material from multiple bacterial generations. D/L profiles in polar ices and in ice-covered lakes (Tsapin et al. 2002, Astrobiology 2, 632) can be used to indicate the sources and histories of water or ice samples. Multiple biological and biogeochemical processes may complicate the interpretation of amino acid enantiomeric excesses in both terrestrial and extraterrestrial samples; however, amino acid racemization remains a useful tool in biogeochemistry and astrobiology. With a good knowledge of the environmental history of samples, amino acid D/L profiles can be used as a window into processes such as molecular repair and biomass turnover that are difficult to

  17. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

  18. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

  19. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

  20. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

  1. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

  2. Alterations of amino Acid level in depressed rat brain.

    PubMed

    Yang, Pei; Li, Xuechun; Ni, Jian; Tian, Jingchen; Jing, Fu; Qu, Changhai; Lin, Longfei; Zhang, Hui

    2014-10-01

    Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats' brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats' brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats' brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and γ-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-α-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, γ-amino-n-butyric acid and L-α-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.

  3. Rotational Study of Natural Amino Acid Glutamine

    NASA Astrophysics Data System (ADS)

    Varela, Marcelino; Cabezas, Carlos; Alonso, José L.

    2014-06-01

    Recent improvements in laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW) have allowed the investigation of glutamine (COOH-CH(NH2)-CH2-CH2-CONH2), a natural amino acid with a long polar side chain. One dominant structure has been detected in the rotational spectrum. The nuclear quadrupole hyperfine structure of two 14N nuclei has been totally resolved allowing the conclusive identification of the observed species.

  4. Amino acid analyses of R and CK chondrites

    NASA Astrophysics Data System (ADS)

    Burton, Aaron S.; McLain, Hannah; Glavin, Daniel P.; Elsila, Jamie E.; Davidson, Jemma; Miller, Kelly E.; Andronikov, Alexander V.; Lauretta, Dante; Dworkin, Jason P.

    2015-03-01

    Exogenous delivery of amino acids and other organic molecules to planetary surfaces may have played an important role in the origins of life on Earth and other solar system bodies. Previous studies have revealed the presence of indigenous amino acids in a wide range of carbon-rich meteorites, with the abundances and structural distributions differing significantly depending on parent body mineralogy and alteration conditions. Here we report on the amino acid abundances of seven type 3-6 CK chondrites and two Rumuruti (R) chondrites. Amino acid measurements were made on hot water extracts from these meteorites by ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Of the nine meteorites analyzed, four were depleted in amino acids, and one had experienced significant amino acid contamination by terrestrial biology. The remaining four, comprised of two R and two CK chondrites, contained low levels of amino acids that were predominantly the straight chain, amino-terminal (n-ω-amino) acids β-alanine, and γ-amino-n-butyric acid. This amino acid distribution is similar to what we reported previously for thermally altered ureilites and CV and CO chondrites, and these n-ω-amino acids appear to be indigenous to the meteorites and not the result of terrestrial contamination. The amino acids may have been formed by Fischer-Tropsch-type reactions, although this hypothesis needs further testing.

  5. Alimentary proteins, amino acids and cholesterolemia.

    PubMed

    Blachier, François; Lancha, Antonio H; Boutry, Claire; Tomé, Daniel

    2010-01-01

    Numerous data from both epidemiological and experimental origins indicate that some alimentary proteins and amino acids in supplements can modify the blood LDL cholesterol, HDL cholesterol and total cholesterol. After an initial approval of the health claim for soy protein consumption for the prevention of coronary heart disease, more recently it has been concluded from an overall analysis of literature that isolated soy protein with isoflavones only slightly decrease LDL and total cholesterol. Other plant extracts and also some proteins from animal origin have been reported to exert a lowering effect on blood cholesterol when compared with a reference protein (often casein). The underlying mechanisms are still little understood. Individual amino acids and mixture of amino acids have also been tested (mostly in animal studies) for their effects on cholesterol parameters and on cholesterol metabolism. Methionine, lysine, cystine, leucine, aspartate and glutamate have been tested individually and in combination in different models of either normo or hypercholesterolemic animals and found to be able to modify blood cholesterol and/or LDL cholesterol and/or HDL cholesterol. It is however not known if these results are relevant to human nutrition.

  6. Concomitant extracellular accumulation of alpha-keto acids and higher alcohols by Zygosaccharomyces rouxii.

    PubMed

    Van Der Sluis, Catrinus; Rahardjo, Yovita S P; Smit, Bart A; Kroon, Pieter J; Hartmans, Sybe; Ter Schure, Eelko G; Tramper, Johannes; Wijffels, Renéh

    2002-01-01

    Alpha-keto acids are key intermediates in the formation of higher alcohols, important flavor components in soy sauce, and produced by the salt-tolerant yeast Zygosaccharomyces rouxii. Unlike most of the higher alcohols, the alpha-keto acids are usually not extracellularly accumulated by Z. rouxii when it is cultivated with ammonium as the sole nitrogen source. To facilitate extracellular accumulation of the alpha-keto acids from aspartate-derived amino acid metabolism, the amino acids valine, leucine, threonine and methionine were exogenously supplied during batch and A-star cultivations of (routants of) Z. rouxii. It was shown that all alpha-keto acids from the aspartate-derived amino acid metabolism, except alpha-ketobutyrate, could be extracellularly accumulated. In addition, it appeared from the concomitant extracellular accumulation of alpha-keto acids and higher alcohols that in Z. rouxii, valine, leucine and methionine were converted via Ehrlich pathways similar to those in Saccharomyces cerevisiae. Unlike these amino acids, threonine was converted via both the Ehrlich and amino acid biosynthetic pathways in Z. rouxii.

  7. Allied Health Chemistry Laboratory: Amino Acids, Insulin, Proteins, and Skin

    ERIC Educational Resources Information Center

    Dever, David F.

    1975-01-01

    Presents a laboratory experiment specifically designed for allied health students. The students construct molecular models of amino acids, extract amino acids from their skin with hot water, and chromatographically analyze the skin extract and hydrolyzed insulin. (MLH)

  8. Allied Health Chemistry Laboratory: Amino Acids, Insulin, Proteins, and Skin

    ERIC Educational Resources Information Center

    Dever, David F.

    1975-01-01

    Presents a laboratory experiment specifically designed for allied health students. The students construct molecular models of amino acids, extract amino acids from their skin with hot water, and chromatographically analyze the skin extract and hydrolyzed insulin. (MLH)

  9. [Novel L-amino acid ligases catalyzing oligopeptide synthesis].

    PubMed

    Kino, Kuniki

    2010-11-01

    L-Amino acid ligase (EC 6.3.2.28) is a microbial enzyme catalyzing formation of an alpha-peptide bond from unprotected L-amino acids in an ATP-dependent manner. The YwfE protein from Bacillus subtilis 168 was the first reported L-amino acid ligase, and it synthesizes various dipeptides. Thereafter, several L-amino acid ligases were newly obtained by in silico analysis using the ATP-grasp motif. But these L-amino acid ligases synthesize only dipeptide and no longer peptide. A novel L-amino acid ligase capable of catalyzing oligopeptide synthesis is required to increase the variety of peptides. We have previously found a new member of L-amino acid ligase, RizA, from B. subtilis NBRC3134, a microorganism that produces the peptide-antibiotic rhizocticin. We newly found that a gene at approximately 9 kbp upstream of rizA encoded a novel L-amino acid ligase RizB. Recombinant RizB synthesized homo-oligomers of branched-chain amino acids consisting of 2 to 5 amino acids, and also synthesized various heteropeptides. RizB is the first reported L-amino acid ligase that catalyzes oligopeptide synthesis. In addition, we obtained L-amino acid ligases showing oligopeptide synthesis activities by in silico analysis using BLAST, which is a set of similarity search programs. These L-amino acid ligases showed low similarity in amino acid sequence, but commonly used branched-chain amino acids, such as RizB, as substrates. Furthermore, the spr0969 protein of Streptococcus pneumoniae synthesized longer peptides than those synthesized by RizB, and the BAD_1200 protein of Bifidobacteria adolescentis showed higher activity toward aromatic amino acids than toward branched-chain ones.

  10. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

  11. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

  12. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

  13. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

  14. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

  15. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

  16. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

  17. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

  18. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

  19. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

  20. Origin, Microbiology, Nutrition, and Pharmacology of D-Amino Acids

    USDA-ARS?s Scientific Manuscript database

    Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids (LAA) to D-amino acids (DAA) and concurrent formation of crosslinked amino acids such as lysinoalanine (LAL). The diet contains both processing-induced and naturally-form...

  1. GCN2 whets the appetite for amino acids.

    PubMed

    Dever, Thomas E; Hinnebusch, Alan G

    2005-04-15

    In response to amino acid starvation, the kinase GCN2 in yeast activates amino acid biosynthesis. Two recent studies (Maurin et al., 2005; Hao et al., 2005) reveal that GCN2 in the brain of mice restricts intake of diets lacking essential amino acids.

  2. Soil amino acid composition across a boreal forest successional sequence

    Treesearch

    Nancy R. Werdin-Pfisterer; Knut Kielland; Richard D. Boone

    2009-01-01

    Soil amino acids are important sources of organic nitrogen for plant nutrition, yet few studies have examined which amino acids are most prevalent in the soil. In this study, we examined the composition, concentration, and seasonal patterns of soil amino acids across a primary successional sequence encompassing a natural gradient of plant productivity and soil...

  3. Nutritional and medicinal aspects of D-amino acids

    USDA-ARS?s Scientific Manuscript database

    This paper describes a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nu...

  4. Amino acid auxotrophy as a system of immunological control nodes.

    PubMed

    Murray, Peter J

    2016-02-01

    Cells of the immune system are auxotrophs for most amino acids, including several nonessential ones. Arginine and tryptophan are used within the regulatory immune networks to control proliferation and function through pathways that actively deplete the amino acid from the microenvironment or that create regulatory molecules such as nitric oxide or kynurenines. How immune cells integrate information about essential amino acid supplies and then transfer these signals to growth and activation pathways remains unclear but has potential for pathway discovery about amino sensing. In applied research, strategies to harness amino acid auxotrophy so as to block cancerous lymphocyte growth have been attempted for decades with limited success. Emerging insights about amino acid metabolism may lead to new strategies in clinical medicine whereby both amino acid auxotrophy and the immunoregulatory pathways controlled by amino acids can be manipulated.

  5. Computational model of abiogenic amino acid condensation to obtain a polar amino acid profile.

    PubMed

    Polanco, Carlos; Buhse, Thomas; Samaniego, José Lino; Castañón González, Jorge Alberto; Arias Estrada, Miguel

    2014-01-01

    In accordance with the second law of thermodynamics, the Universe as a whole tends to higher entropy. However, the sequence of far-from-equilibrium events that led to the emergence of life on Earth could have imposed order and complexity during the course of chemical reactions in the so-called primordial soup of life. Hence, we may expect to find characteristic profiles or biases in the prebiotic product mixtures, as for instance among the first amino acids. Seeking to shed light on this hypothesis, we have designed a high performance computer program that simulates the spontaneous formation of the amino acid monomers in closed environments. The program was designed in reference to a prebiotic scenario proposed by Sydney W. Fox. The amino acid abundances and their polarities as the two principal biases were also taken into consideration. We regarded the computational model as exhaustive since 200,000 amino acid dimers were formed by simulation, subsequently expressed in a vector and compared with the corresponding amino acid dimers that were experimentally obtained by Fox. We found a very high similarity between the experimental results and our simulations.

  6. Intestinal absorption of amino acids and peptides in Hartnup disorder.

    PubMed

    Leonard, J V; Marrs, T C; Addison, J M; Burston, D; Clegg, K M; Lloyd, J K; Matthews, D M; Seakins, J W

    1976-04-01

    Absorption of free and peptide-bound amino acids was investigated in a girl with Hartnup disorder aged 26 months. Plasma levels of amino acids were followed after oral administration of (1) an amino acid mixture simulating casein and (2) an equivalent dose of a partial enzymic hydrolysate of casein containing oligopeptides in addition to free amino acids. The results suggested that many neutral amino acids were poorly absorbed when given in the free form, but much more readily absorbed when given as peptides. Unexpectedly, the results also suggested that glutamic acid was poorly absorbed when given in the free form. The results obtained with threonine could not be interpreted. There was an increased renal clearance of many neutral amino acids, including glycine, but clearance of proline was not increased. Most amino acids with an increased renal clearance also appeared to be poorly absorbed when given by mouth in the free form.

  7. Evidence that synaptosomal high-affinity carriers for amino acid neurotransmitters are glycosylated

    SciTech Connect

    Zaleska, M.M.; Erecinska, M.

    1987-05-01

    The effect of removal of surface sialic acid from synaptosomes on the high-affinity, Na/sup +/-dependent uptake systems for amino acid neurotransmitters was evaluated. Synaptosomes from rat forebrain were preincubated with neuraminidase from Vibrio cholerae for 20 min at 34/sup 0/. After washing and resuspension, their ability to transport /sup 14/C-GABA and the acidic amino acid, /sup 3/H-aspartate was studied. Pretreatment with neuraminidase resulted in a concentration-dependent inhibition of the uptake of both amino acids while the influx of /sup 3/H-L-leucine was unaffected. Inhibition was a function of the amount of sialic acid released from membranes. The analysis of the kinetic parameters of amino acid uptake revealed that inhibition resulted from a decrease of Vmax without any change in the Km. Neither the synaptosomal energy levels nor the internal concentration of potassium ions was affected by the pretreatment with neuraminidase. The maximum accumulation ratios for both amino acids remained largely unaltered. It is concluded that the GABA and acidic amino acid transporters are glycosylated and that sialic acid is involved in the operation of carrier proteins directly and not through modification of the driving forces responsible for amino acid transport.

  8. Neighbor Preferences of Amino Acids and Context-Dependent Effects of Amino Acid Substitutions in Human, Mouse, and Dog

    PubMed Central

    Fu, Mingchuan; Huang, Zhuoran; Mao, Yuanhui; Tao, Shiheng

    2014-01-01

    Amino acids show apparent propensities toward their neighbors. In addition to preferences of amino acids for their neighborhood context, amino acid substitutions are also considered to be context-dependent. However, context-dependence patterns of amino acid substitutions still remain poorly understood. Using relative entropy, we investigated the neighbor preferences of 20 amino acids and the context-dependent effects of amino acid substitutions with protein sequences in human, mouse, and dog. For 20 amino acids, the highest relative entropy was mostly observed at the nearest adjacent site of either N- or C-terminus except C and G. C showed the highest relative entropy at the third flanking site and periodic pattern was detected at G flanking sites. Furthermore, neighbor preference patterns of amino acids varied greatly in different secondary structures. We then comprehensively investigated the context-dependent effects of amino acid substitutions. Our results showed that nearly half of 380 substitution types were evidently context dependent, and the context-dependent patterns relied on protein secondary structures. Among 20 amino acids, P elicited the greatest effect on amino acid substitutions. The underlying mechanisms of context-dependent effects of amino acid substitutions were possibly mutation bias at a DNA level and natural selection. Our findings may improve secondary structure prediction algorithms and protein design; moreover, this study provided useful information to develop empirical models of protein evolution that consider dependence between residues. PMID:25210846

  9. [Study on basic amino acid contents in Dendrobium officinale].

    PubMed

    Zhang, Ailian; Wei, Tao; Si, Jinping'; Jin, Luying; Mo, Yina

    2011-10-01

    To investigate the contents of 16 basic amino acid and find out the variation of them in Dendrobium officinale with different germplasms and physiological ages, and then provide scientific basis for the quality evaluation and the breeding of D. officinale. Thirty-three samples with 1-3 ages were collected from cultivated fields of Zhejiang. The samples were acid hydrolyzed, and then 16 basic amino acid contents of samples were determined by amino acid analyzer. The average contents of 7 necessary amino acid were in 0.28 - 2.96 mg x g(-1), the average contents of other 9 basic amino acid were in 0.53 - 4.20 mg x g(-1). The contents of many amino acids were impacted by germplasms significantly, and contents of several amino acids were impacted by physiological ages significantly. There were rich basic amino acids in D. officinale. The breeding of D. officinale can increase the contents of essential amino acids and other basic amino acids. The relations among physiological age and amino acid contents were as follows: three years > two years > one year. The contents of Asp and Tyr have significantly negative correlation with magnesium, the content of Pro has significantly positive correlation with copper.

  10. Synthesis of new kojic acid based unnatural α-amino acid derivatives.

    PubMed

    Balakrishna, C; Payili, Nagaraju; Yennam, Satyanarayana; Devi, P Uma; Behera, Manoranjan

    2015-11-01

    An efficient method for the preparation of kojic acid based α-amino acid derivatives by alkylation of glycinate schiff base with bromokojic acids have been described. Using this method, mono as well as di alkylated kojic acid-amino acid conjugates have been prepared. This is the first synthesis of C-linked kojic acid-amino acid conjugate where kojic acid is directly linked to amino acid through a C-C bond.

  11. [Impairments of placental amino acid metabolism in fetal growth restriction].

    PubMed

    Pogorelova, T N; Gunko, V O; Avrutskaya, V V; Kaushanskaya, L V; Durnitsyna, O A

    2017-05-01

    The content of the amino acids in the placenta during physiological pregnancy and fetal growth restriction (FGR) has been investigated my means of the method of ion-exchange chromatography. It has been found that in FGR the placental amino acid pool is characterized by a decreased content of arginine, proline, alanine, serine, cysteine, methionine, tryptophan, leucine, threonine, tyrosine, phenylalanine, glutamine and an increased content of dicarboxylic amino acids, lysine, histidine and glycine. These changes are accompanied by altered activity of some enzymes of amino acid metabolism, and the degree of these changes correlates with the level of corresponding amino acids.

  12. [Bound amino acids in local strains of Trichomonas vaginalis].

    PubMed

    Tsvetkova, A; Osinovski, E; Vasilevska, M

    1990-01-01

    Amino acid composition of water-soluble and water-insoluble proteins of 8 strains of Tr. vaginalis is studied. 17 amino acids are found in both protein hydrolyzates. Despite the complete coincidence of their qualitative compositions there are reliable differences in the quantitative contents of some amino acids. Differences in the contents of main amino acids of water-soluble proteins of different strains reflect the belonging of the latter to different sero-groups. No reliable differences in the quantitative contents of amino acids of both water-soluble and water-insoluble proteins in strains belonging to one sero-group are recognised.

  13. Amino acids from the late Precambrian Thule group, Greenland.

    PubMed

    Akiyama, M; Shimoyama, A; Ponnamperuma, C

    1982-06-01

    Amino acids were recovered at concentration level of 10-9 M/g from the interior of chert and dolomite of the Late Precambrian Thule Group. Examination of the stability of amino acids in chert under dry-heating conditions suggests that these amino acids have been preserved with a predominance of L-enantiomers in the precambrian chert. Enantiomer analysis of amino acids in dolomite showed a thermal effect resulting from a late precambrian igneous intrusion. This evidence indicates that the amino acids isolated from the Thule samples were chemical fossils and not recent contaminants.

  14. Free Amino-acid Concentrations in Fetal Fluids

    PubMed Central

    Cockburn, F.; Robins, S. P.; Forfar, J. O.

    1970-01-01

    The pattern of free amino-acid concentrations in maternal venous plasma, fetal umbilical arterial plasma, fetal urine, and amniotic fluid at 15 to 20 weeks' gestation has been determined. Free amino-acid concentrations were greater in fetal plasma than in maternal plasma, amniotic fluid, or fetal urine. The ratios of amino-acid concentrations in fetal umbilical arterial plasma and urine indicate that the fetal kidney can effectively conserve amino-acids, possibly reaching an adult level of competence in this respect. There was little correlation between amino-acid concentrations in the fluids analysed with the exception of that between amniotic fluid and fetal urine. PMID:5472758

  15. Light-activated amino acid transport in Halobacterium halobium envelope vesicles

    NASA Technical Reports Server (NTRS)

    Macdonald, R. E.; Lanyi, J. K.

    1977-01-01

    Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.

  16. Light-activated amino acid transport in Halobacterium halobium envelope vesicles

    NASA Technical Reports Server (NTRS)

    Macdonald, R. E.; Lanyi, J. K.

    1977-01-01

    Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.

  17. Protein and Amino Acid Requirements during Pregnancy.

    PubMed

    Elango, Rajavel; Ball, Ronald O

    2016-07-01

    Protein forms an essential component of a healthy diet in humans to support both growth and maintenance. During pregnancy, an exceptional stage of life defined by rapid growth and development, adequate dietary protein is crucial to ensure a healthy outcome. Protein deposition in maternal and fetal tissues increases throughout pregnancy, with most occurring during the third trimester. Dietary protein intake recommendations are based on factorial estimates because the traditional method of determining protein requirements, nitrogen balance, is invasive and undesirable during pregnancy. The current Estimated Average Requirement and RDA recommendations of 0.88 and 1.1 g · kg(-1) · d(-1), respectively, are for all stages of pregnancy. The single recommendation does not take into account the changing needs during different stages of pregnancy. Recently, with the use of the minimally invasive indicator amino acid oxidation method, we defined the requirements to be, on average, 1.2 and 1.52 g · kg(-1) · d(-1) during early (∼16 wk) and late (∼36 wk) stages of pregnancy, respectively. Although the requirements are substantially higher than current recommendations, our values are ∼14-18% of total energy and fit within the Acceptable Macronutrient Distribution Range. Using swine as an animal model we showed that the requirements for several indispensable amino acids increase dramatically during late gestation compared with early gestation. Additional studies should be conducted during pregnancy to confirm the newly determined protein requirements and to determine the indispensable amino acid requirements during pregnancy in humans. © 2016 American Society for Nutrition.

  18. Stimulation of nonselective amino acid export by glutamine dumper proteins.

    PubMed

    Pratelli, Réjane; Voll, Lars M; Horst, Robin J; Frommer, Wolf B; Pilot, Guillaume

    2010-02-01

    Phloem and xylem transport of amino acids involves two steps: export from one cell type to the apoplasm, and subsequent import into adjacent cells. High-affinity import is mediated by proton/amino acid cotransporters, while the mechanism of export remains unclear. Enhanced expression of the plant-specific type I membrane protein Glutamine Dumper1 (GDU1) has previously been shown to induce the secretion of glutamine from hydathodes and increased amino acid content in leaf apoplasm and xylem sap. In this work, tolerance to low concentrations of amino acids and transport analyses using radiolabeled amino acids demonstrate that net amino acid uptake is reduced in the glutamine-secreting GDU1 overexpressor gdu1-1D. The net uptake rate of phenylalanine decreased over time, and amino acid net efflux was increased in gdu1-1D compared with the wild type, indicating increased amino acid export from cells. Independence of the export from proton gradients and ATP suggests that overexpression of GDU1 affects a passive export system. Each of the seven Arabidopsis (Arabidopsis thaliana) GDU genes led to similar phenotypes, including increased efflux of a wide spectrum of amino acids. Differences in expression profiles and functional properties suggested that the GDU genes fulfill different roles in roots, vasculature, and reproductive organs. Taken together, the GDUs appear to stimulate amino acid export by activating nonselective amino acid facilitators.

  19. Organic geochemistry of amino acids: Precambrian to recent

    SciTech Connect

    Engel, M.H.; Macko, S.A.

    1985-01-01

    Since the discovery of amino acids in fossils (Abelson, 1954), considerable effort has been made to elucidate the origin and distribution of amino acids in geologic materials. Racemization and decomposition reactions of amino acids and peptides derived via the natural hydrolysis of protein constituents of organisms have been extensively studied. While the ubiquity of amino acids presents a challenge for discerning their indigeneity in geologic samples, careful analyses have resulted in successful applications of amino acid racemization and decomposition reactions for investigations of geochronologic, paleoclimatic, stratigraphic, diagenetic and chemotaxonomic problems for Quaternary age samples. An investigation of amino acids in sediments from Baffin Island fjords indicates that their distribution may also provide data with respect to the relative contributions of marine and terrigenous organic matter to recent sediments. While the absence of unstable amino acids and the presence of racemic amino acids in a sample may preclude very recent contamination, the possibility of retardation of amino acid racemization rates subsequent to geopolymer formation must also be considered. Studies of amino acids in Paleozoic, Mesozoic and early Cenozoic age samples are limited. Precambrian samples, however, have received much attention, given the potential (however slight) for isolating compounds representative of the earliest living systems. A future approach for elucidating the origin(s) of amino acids in ancient samples may be analyses of their individual stable isotopic compositions.

  20. Dissolved amino acids in oceanic basaltic basement fluids

    NASA Astrophysics Data System (ADS)

    Lin, Huei-Ting; Amend, Jan P.; LaRowe, Douglas E.; Bingham, Jon-Paul; Cowen, James P.

    2015-09-01

    The oceanic basaltic basement contains the largest aquifer on Earth and potentially plays an important role in the global carbon cycle as a net sink for dissolved organic carbon (DOC). However, few details of the organic matter cycling in the subsurface are known because great water depths and thick sediments typically hinder direct access to this environment. In an effort to examine the role of water-rock-microorganism interaction on organic matter cycling in the oceanic basaltic crust, basement fluid samples collected from three borehole observatories installed on the eastern flank of the Juan de Fuca Ridge were analyzed for dissolved amino acids. Our data show that dissolved free amino acids (1-13 nM) and dissolved hydrolyzable amino acids (43-89 nM) are present in the basement. The amino acid concentrations in the ridge-flank basement fluids are at the low end of all submarine hydrothermal fluids reported in the literature and are similar to those in deep seawater. Amino acids in recharging deep seawater, in situ amino acid production, and diffusional input from overlying sediments are potential sources of amino acids in the basement fluids. Thermodynamic modeling shows that amino acid synthesis in the basement can be sustained by energy supplied from inorganic substrates via chemolithotrophic metabolisms. Furthermore, an analysis of amino acid concentrations and compositions in basement fluids support the notion that heterotrophic activity is ongoing. Similarly, the enrichment of acidic amino acids and depletion of hydrophobic ones relative to sedimentary particulate organic matter suggests that surface sorption and desorption also alters amino acids in the basaltic basement. In summary, although the oceanic basement aquifer is a net sink for deep seawater DOC, similar amino acid concentrations in basement aquifer and deep seawater suggest that DOC is preferentially removed in the basement over dissolved amino acids. Our data also suggest that organic carbon

  1. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  2. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the snythesis methods of the prior art.

  3. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  4. Characterization of amino acids using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Jenkins, Amanda L.; Larsen, Richard A.; Williams, Timothy B.

    2005-05-01

    A key process in the development of new drugs is elucidation of the interaction between the drug molecule and the target protein. Such knowledge then makes it possible to make systematic structural modifications of the drug molecule to optimize the interaction. Many analytical techniques can be applied to proteins in solution such as circular dichroism, ultraviolet, and fluorescence spectroscopy but these all have limitations. In this paper, we investigate the feasibility of using relatively simple, visible light Raman spectroscopic methods to investigate amino acids and related biopolymers.

  5. Intermolecular Vibrations of Hydrophobic Amino Acids

    NASA Astrophysics Data System (ADS)

    Williams, Michael Roy Casselman

    Hydrophobic amino acids interact with their chemical environment through a combination of electrostatic, hydrogen bonding, dipole, induced dipole, and dispersion forces. These interactions all have their own characteristic energy scale and distance dependence. The low-frequency (0.1-5 THz, 5-150 cm-1) vibrational modes of amino acids in the solid state are a direct indicator of the interactions between the molecules, which include interactions between an amino acid functional group and its surroundings. This information is central to understanding the dynamics and morphology of proteins. The alpha-carbon is a chiral center for all of the hydrophobic amino acids, meaning that they exist in two forms, traditionally referred to as L- and D-enantiomers. This nomenclature indicates which direction the molecule rotates plane-polarized visible light (levorotory and dextrorotory). Chiral a-amino acids in proteins are exclusively the L-variety In the solid state, the crystal lattice of the pure L-enantiomer is the mirror image of the D-enantiomer crystal lattice. These solids are energetically identical. Enantiomers also have identical spectroscopic properties except when the measurement is polarization sensitive. A mixture of equal amounts D- and L-amino acid enantiomers can crystallize into a racemic (DL-) structure that is different from that of the pure enantiomers. Whether a solution of both enantiomers will crystallize into a racemic form or spontaneously resolve into a mixture of separate D- and L-crystals largely depends on the interactions between molecules available in the various possible configurations. This is an active area of research. Low-frequency vibrations with intermolecular character are very sensitive to changes in lattice geometry, and consequently the vibrational spectra of racemic crystals are usually quite distinct from the spectra of the crystals of the corresponding pure enantiomers in the far-infrared (far-IR). THz time-domain spectroscopy (THz

  6. Food safety and amino acid balance in processed cassava "Cossettes".

    PubMed

    Diasolua Ngudi, Delphin; Kuo, Yu Haey; Lambein, Fernand

    2002-05-08

    Processed cassava (Manihot esculenta Crantz) roots provide more than 60% of the daily energy intake for the population of the Democratic Republic of Congo. Insufficiently processed cassava roots in a diet deficient in sulfur amino acid have been reported to cause the irreversible paralytic disease konzo, afflicting thousands of women and children in the remote rural areas of Bandundu Province. "Cossettes" (processed cassava roots) purchased in several markets of Kinshasa were analyzed for their content of cyanogens, free amino acids, and total protein amino acids. Residual cyanogen levels were below the safe limit recommended by the codex FAO/WHO for cassava flour (10 mg kg(-1)). The amino acid score was evaluated. Lysine and leucine were the limiting amino acids. Methionine content was very low and contributed about 13% of the total sulfur amino acids. Dietary requirements for sulfur amino acids need to be adjusted for the loss caused by cyanogen detoxification.

  7. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.

    2010-01-01

    Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, R-amino-n-butyric acid (beta-ABA), 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L approximately 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha-aminoisobutyric acid (alpha-AIB), 4-amino-2- methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and alpha-AIB in Almahata Sitta are 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures.

  8. Extraterrestrial amino acids in the Almahata Sitta meteorite

    NASA Astrophysics Data System (ADS)

    Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.; Jenniskens, Peter; Shaddad, Muawia H.

    2010-10-01

    Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, β-amino-n-butyric acid, 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L ˜ 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other nonprotein amino acids were also identified in the meteorite above background levels including α-aminoisobutyric acid (α-AIB), 4-amino-2-methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and α-AIB in Almahata Sitta are approximately 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five-carbon amino acids in Almahata Sitta compared to CI, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures, or introduced as a contaminant from unrelated meteorite clasts and chemically altered by α-decarboxylation.

  9. Evolutionary systems biology of amino acid biosynthetic cost in yeast.

    PubMed

    Barton, Michael D; Delneri, Daniela; Oliver, Stephen G; Rattray, Magnus; Bergman, Casey M

    2010-08-17

    Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental conditions, we conclude that

  10. Evolutionary Systems Biology of Amino Acid Biosynthetic Cost in Yeast

    PubMed Central

    Barton, Michael D.; Delneri, Daniela; Oliver, Stephen G.; Rattray, Magnus; Bergman, Casey M.

    2010-01-01

    Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental conditions, we conclude that

  11. Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

  12. Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

  13. Intestinal transport of sugars and amino acids in diabetic rats

    PubMed Central

    Olsen, Ward A.; Rosenberg, Irwin H.

    1970-01-01

    The specificity and mechanism of altered intestinal transport of diabetic rats was studied with an everted ring technique. Increased intracellular accumulation of amino acids, as well as galactose and 3-O-methylglucose, was demonstrated in diabetes. The greater accumulation by diabetic intestine could not be attributed to a direct effect of the agent used to induce diabetes or to an alteration in food consumption. Although the changes were related to the severity of diabetes and could be reversed with treatment with insulin, they could not be modified by addition of insulin in vitro. The changes could not be induced in control intestine either with hyperglycemia from glucose infusion or preincubation with glucose in vitro. Although the higher concentration gradients of amino acids, galactose, and 3-O-methylglucose could result from increased energy utilization by diabetic intestine, an alteration of cell membrane function, as well, is suggested by the demonstration with kinetic studies of increased influx with an increase in Vmax. PMID:5409812

  14. Beneficial Effects of the Amino Acid Glycine.

    PubMed

    Pérez-Torres, Israel; Zuniga-Munoz, Alejandra María; Guarner-Lans, Veronica

    2017-01-01

    Glycine is the smallest non-essential, neutral and metabolically inert amino acid, with a carbon atom bound to two hydrogen atoms, and to an amino and a carboxyl group. This amino acid is an essential substrate for the synthesis of several biologically important biomolecules and compounds. It participates in the synthesis of proteins, of the tripeptide glutathione and in detoxification reactions. It has a broad spectrum of anti-inflammatory, cytoprotective and immunomodulatory properties. To exert its actions, glycine binds to different receptors. The GlyR anion channel is the most studied receptor for glycine. However, there are GlyR-independent mechanisms for glycine cytoprotection and other possible binding molecules of glycine are the NMDA receptor and receptors GlyT1 and GlyT2. Although, in humans, the normal serum level of glycine is approximately 300 μM, increasing glycine intake can lead to blood levels of more than 900 μM that increase its benefic actions without having harmful side effects. The herbal pesticide glyphosate might disrupt glycine homeostasis. Many in vitro studies involving different cell types have demonstrated beneficial effects of the addition of glycine. Glycine also improved conditions of isolated perfused or stored organs. In vivo studies in experimental animals have also tested glycine as a protector molecule and some studies on the beneficial effects of glycine after its clinical application have been done. Although at high-doses, glycine may cause toxic effects, further studies are needed to investigate the safe range of usage of this aminoacid and to test the diverse routes of administration.

  15. Bovine testis acylphosphatase: purification and amino acid sequence.

    PubMed

    Pazzagli, L; Cappugi, G; Camici, G; Manao, G; Ramponi, G

    1993-10-01

    Two acylphosphatase molecular forms have been isolated from bovine testis. Their amino acid sequence was determined. One (ACY1) consists of 98 amino acid residues, while the other one (ACY2) consists of 100 amino acid residues. Both molecular forms are N-acetylated and differ only in the amino terminus. ACY2 has an additional Ser-Met tail with respect to ACY1. Both ACY1 and ACY2 are organ-common type isoenzymes and thus differ for about half of the amino acid positions from the previously sequenced bovine muscle isoenzyme.

  16. Amino acids in healthy aging skeletal muscle.

    PubMed

    Riddle, Emily S; Stipanuk, Martha H; Thalacker-Mercer, Anna E

    2016-01-01

    Life expectancy in the U.S. and globally continues to increase. Despite increased life expectancy quality of life is not enhanced, and older adults often experience chronic age-related disease and functional disability, including frailty. Additionally, changes in body composition such as the involuntary loss of skeletal muscle mass (i.e. sarcopenia) and subsequent increases in adipose tissue can augment disease and disability in this population. Furthermore, increased oxidative stress and decreased antioxidant concentrations may also lead to metabolic dysfunction in older adults. Specific amino acids, including leucine, cysteine and its derivative taurine, and arginine can play various roles in healthy aging, especially in regards to skeletal muscle health. Leucine and arginine play important roles in muscle protein synthesis and cell growth while cysteine and arginine play important roles in quenching oxidative stress. Evidence suggests that supplemental doses of each of these amino acids may improve the aging phenotype. However, additional research is required to establish the doses required to achieve positive outcomes in humans.

  17. Conformational properties of oxazoline-amino acids

    NASA Astrophysics Data System (ADS)

    Staś, Monika; Broda, Małgorzata A.; Siodłak, Dawid

    2016-04-01

    Oxazoline-amino acids (Xaa-Ozn) occur in natural peptides of potentially important bioactivity. The conformations of the model compounds: Ac-(S)-Ala-Ozn(4R-Me), Ac-(S)-Ala-Ozn(4S-Me), and (gauche+, gauche-, anti) Ac-(S)-Val-Ozn(4R-Me) were studied at meta-hybrid M06-2X/6-311++G(d,p) method including solvent effect. Boc-L-Ala-L-Ozn-4-COOMe and Boc-L-Val-L-Ozn-4-COOMe were synthesized and studied by FT-IR and NMR-NOE methods. The conformations in crystal state were gathered from the Cambridge Structural Data Base. The main conformational feature of the oxazoline amino acids is the conformation β2 (ϕ,ψ ∼ -161°, -6°), which predominates in weakly polar environment and still is accessible in polar surrounding. The changes of the conformational preferences towards the conformations αR (ϕ,ψ ∼ -70°, -15°) and then β (ϕ,ψ ∼ -57°, -155°) are observed with increase of the environment polarity.

  18. Kinetic Trapping of Metastable Amino Acid Polymorphs

    NASA Astrophysics Data System (ADS)

    Simpson, Garth

    2014-06-01

    Second harmonic generation (SHG) microscopy was integrated with synchrotron X-ray diffraction (XRD) to test the Ostwald Rule of Stages, in which is hypothesized that crystals dynamically transition through metastable polymorphs before settling on the most thermodynamically favored form. The presence or absence of metastable forms has historically been challenging to probe due to the stochastic randomness of crystal nucleation coupled with the relatively short time-frame over which the metastable forms may survive. In this work, inkjet printing of a racemic amino acid solutions results in rapid solvent evaporation, placing crystallization under kinetic rather than thermodynamic control. SHG microscopy is used to rapidly and selectively identify the positions of metastable crystal forms. Coupling this measurement with synchrotron XRD allows diffraction analysis to be performed on individual inkjet printed dots of only a few pg of total material, prepared from single 1 pL droplets. In studies of amino acids, we have shown that the homochiral crystals emerge when printed, while those same solutions exclusively generate the racemic co-crystals upon slow solvent evaporation.

  19. Amphipathic helices from aromatic amino acid oligomers.

    PubMed

    Gillies, Elizabeth R; Dolain, Christel; Léger, Jean-Michel; Huc, Ivan

    2006-10-13

    Synthetic helical foldamers are of significant interest for mimicking the conformations of naturally occurring molecules while at the same time introducing new structures and properties. In particular, oligoamides of aromatic amino acids are attractive targets, as their folding is highly predictable and stable. Here the design and synthesis of new amphipathic helical oligoamides based on quinoline-derived amino acids having either hydrophobic or cationic side chains are described. Their structures were characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR. Results of these studies suggest that an oligomer as short as a pentamer folds into a stable helical conformation in protic solvents, including MeOH and H(2)O. The introduction of polar proteinogenic side chains to these foldamers, as described here for the first time, promises to provide possibilities for the biological applications of these molecules. In particular, amphipathic helices are versatile targets to explore due to their importance in a variety of biological processes, and the unique structure and properties of the quinoline-derived oligoamides may allow new structure-activity relationships to be developed.

  20. Formation and transformation of amino acids and amino acid precursors by high-velocity impacts

    NASA Astrophysics Data System (ADS)

    Kaneko, T.; Kobayashi, K.; Yamori, A.

    A wide variety of organic compounds have been found in extraterrestrial bodies such as comets and carbonaceous chondrites. It is plausible that these extraterrestrial bodies carried organic compounds such as amino acids or their precursors to the early Earth. It is claimed, however, that these extraterrestrial organics were destroyed during impacts to the Earth. We therefore examined possible transformation of amino acids and their precursors during high-velocity impacts by using a rail gun "HYPAC" in ISAS. Starting materials used in the impact experiments were (i) aqueous solution of glycine (10 mM or 1.0 M), and (ii) a mixture of ammonia, methanol and water. The target materials were sealed in stainless steel capsules, and shocked by impact with a polycarbonate projectile accelerated with "HYPAC" to the velocities of 2.5 - 7.0 km/s. A part of the products was acid-hydrolyzed. Both hydrolyzed an unhydrolyzed products were analyzed by mass spectrometry, high performance liquid chromatography and capillary electrophoresis and chromatography. When an aqueous solution containing ammonia, methanol and water was shocked by impact at the velocity of 6.4 km/s, a number of amino acids (e.g., serine and glycine) were detected after hydrolysis. The present results suggest that amino acid precursors could be formed during cometary impacts. When glycine solution was used as a starting material, about 40 % of glycine was recovered even after 6 km/s impact. Methylamine and ammonia, which are known as pyrolytic products of glycine, were detected, besides them, diketopiperazine and an unidentified product whose molecular weight was 134, were detected, while no glycine peptides were identified in them. It was shown that the impact processes resulted in the formation of amino acid condensates. Thermal stability of glycine precursor is comparable with glycine. The present results suggest that organic material could survive and/or formed during an impact process. Most of organic

  1. Inadequacy of prebiotic synthesis as origin of proteinous amino acids.

    PubMed

    Wong, J T; Bronskill, P M

    1979-07-18

    The production of some nonproteinous, and lack of production of other proteinous, amino acids in model prebiotic synthesis, along with the instability of glutamine and asparagine, suggest that not all of the 20 present day proteinous amino acids gained entry into proteins directly from the primordial soup. Instead, a process of active co-evolution of the genetic code and its constituent amino acids would have to precede the final selection of these proteinous amono acids.

  2. Prebiotic Synthesis of Hydrophobic and Protein Amino Acids

    PubMed Central

    Ring, David; Wolman, Yecheskel; Friedmann, Nadav; Miller, Stanley L.

    1972-01-01

    The formation of amino acids by the action of electric discharges on a mixture of methane, nitrogen, and water with traces of ammonia was studied in detail. The presence of glycine, alanine, α-amino-n-butyric acid, α-aminoisobutyric acid, valine, norvaline, isovaline, leucine, isoleucine, alloisoleucine, norleucine, proline, aspartic acid, glutamic acid, serine, threonine, allothreonine, α-hydroxy-γ-aminobutyric acid, and α,γ-diaminobutyric acid was confirmed by ion-exchange chromatography and gas chromatography-mass spectrometry. All of the primary α-amino acids found in the Murchison Meteorite have been synthesized by this electric discharge experiment. PMID:4501592

  3. Amino Acid Transport in Mycobacterium smegmatis

    PubMed Central

    Yabu, Kunihiko

    1970-01-01

    The transport of d-alanine, d-glutamic acid, and d-valine in Mycobacterium smegmatis was compared quantitatively with that of their l-isomers. It appeared that the uptake of d-alanine was mediated by an active process displaying saturation kinetics characteristic of enzyme function, whereas the uptake of d-glutamic acid was accomplished by a passive process showing diffusion kinetics. Both processes were involved in the uptake of l-alanine, l-glutamic acid, d-valine, and l-valine. d-Valine competed with l-valine for entry into the cell through a single active process. d-Alanine and l-alanine also utilized the same active process, but the d-isomer could not enter the cell through the passive process. The passive process exhibited characteristics of diffusion, but was sensitive to sulfhydryl-blocking reagents and showed competition among structurally related amino acids. These last findings suggested that the passive process is a facilitated diffusion. PMID:5437732

  4. ANTIGENICITY OF POLYPEPTIDES (POLY ALPHA AMINO ACIDS)

    PubMed Central

    Maurer, Paul H.; Gerulat, Bernard F.; Pinchuck, Paul

    1964-01-01

    A new group of synthetic random polymers of α-L-amino acids has been studied for immunogenicity. With the glutamic acid and alanine copolymers, those consisting of almost equimolar amounts of the two (G60A40 and G40A60) were effective antigens in rabbits whereas those with higher glutamic acid contents (G75A25, G90A10) were poor antigens. The substitution of alanine by valine or leucine (G75V25 and G80Leu20) produced copolymers which were poor antigens in rabbits but effective in guinea pigs. L70A30, although capable of "non-specifically" precipitating serum proteins, was shown not to be antigenic in either rabbits or guinea pigs. The introduction of alanine into glutamic acid and lysine polymers (GLA series) enhanced the immunogenicity of the terpolymers, i.e., GLA30 > GLA20 > GLA10 > GL. The mechanism by which this may be accomplished is discussed as possibly being related to the reduction of the interactions between glutamyl and lysyl residues which allows the carboxyl groups to act as strong immunogenic determinants. PMID:14176288

  5. A reexamination of amino acids in lunar soil

    NASA Astrophysics Data System (ADS)

    Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

    1993-03-01

    Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

  6. Relative Amino Acid Composition Signatures of Organisms and Environments

    PubMed Central

    Moura, Alexandra; Savageau, Michael A.; Alves, Rui

    2013-01-01

    Background Identifying organism-environment interactions at the molecular level is crucial to understanding how organisms adapt to and change the chemical and molecular landscape of their habitats. In this work we investigated whether relative amino acid compositions could be used as a molecular signature of an environment and whether such a signature could also be observed at the level of the cellular amino acid composition of the microorganisms that inhabit that environment. Methodologies/Principal Findings To address these questions we collected and analyzed environmental amino acid determinations from the literature, and estimated from complete genomic sequences the global relative amino acid abundances of organisms that are cognate to the different types of environment. Environmental relative amino acid abundances clustered into broad groups (ocean waters, host-associated environments, grass land environments, sandy soils and sediments, and forest soils), indicating the presence of amino acid signatures specific for each environment. These signatures correlate to those found in organisms. Nevertheless, relative amino acid abundance of organisms was more influenced by GC content than habitat or phylogeny. Conclusions Our results suggest that relative amino acid composition can be used as a signature of an environment. In addition, we observed that the relative amino acid composition of organisms is not highly determined by environment, reinforcing previous studies that find GC content to be the major factor correlating to amino acid composition in living organisms. PMID:24204807

  7. A reexamination of amino acids in lunar soil

    NASA Technical Reports Server (NTRS)

    Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

    1993-01-01

    Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

  8. A reexamination of amino acids in lunar soil

    NASA Technical Reports Server (NTRS)

    Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

    1993-01-01

    Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

  9. Available amino acid score for evaluating protein quality of foods.

    PubMed

    Sarwar, G

    1984-01-01

    Amino acid scores corrected for true digestibility of individual amino acids (as determined by rat balance method) were termed "available amino acid scores" in the present investigation. Available amino acid scores were calculated for 7 protein sources and their 10 supplementary or complementary mixtures which have been tested in collaborative amino acid and rat growth assays for evaluating protein quality. The available amino acid scores were as follows: casein + methionine (100); egg white (100); rapeseed protein concentrate, RPC (94); casein (93); beef (89); soya assay protein, SAP (62); pea flour (61); whole wheat flour, WW (38); SAP + methionine (88); pea flour + methionine (72); WW + lysine (67); WW + casein (84); WW + egg white (79); WW + RPC (65); WW + beef (77); WW + SAP (70); and WW + pea flour (75). These scores were similar to the collaborative relative NPR values; the differences were less than 10 units (2-9 units) in most cases. The positive correlation (r = 0.92) between available amino acid scores and relative net protein ratio (RNPR, a rat growth method) values was highly significant (P less than 0.01) and the origin of the regression line (y = 0.92x + 1.88) was not significantly different from zero. Amino acid bioavailability has previously been a problem, preventing widespread acceptance of amino acid score. Available amino acid score solves this problem.

  10. Limiting amino acids in bengal gram (Cicer arietinum) as determined from blood amino acid levels and amino acid supplementation studies in the rat.

    PubMed

    Khader, V; Rao, S V

    1982-01-01

    The limiting amino acids of Bengal gram (Cicer arietinum) were determined from plasma amino acid score and ratio and growth response of weanling rats to supplements of amino acids. The results indicated that methionine, threonine and tryptophan are the most limiting amino acids. Protein efficiency ratio of raw and cooked Bengal gram fed at a dietary level of 10% protein increased from 2.7 to 3.7 and 2.4 to 3.4, respectively, on supplementing the diets with methionine, threonine and tryptophan. Plasma levels of lysine, methionine, threonine and tryptophan were similar in rats fed raw or cooked Bengal gram, indicating that the trypsin or other inhibitors that may be present in the raw gram do not affect the biological availability of these amino acids.

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

    PubMed

    Ganesan, Balasubramanian; Seefeldt, Kimberly; Weimer, Bart C

    2004-11-01

    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.

  12. Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions

    NASA Astrophysics Data System (ADS)

    Tarasevych, Arkadii V.; Vives, Thomas; Snytnikov, Valeriy N.; Guillemin, Jean-Claude

    2017-03-01

    The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.

  13. Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions

    NASA Astrophysics Data System (ADS)

    Tarasevych, Arkadii V.; Vives, Thomas; Snytnikov, Valeriy N.; Guillemin, Jean-Claude

    2017-09-01

    The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.

  14. Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions.

    PubMed

    Tarasevych, Arkadii V; Vives, Thomas; Snytnikov, Valeriy N; Guillemin, Jean-Claude

    2017-03-31

    The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.

  15. A family of yeast proteins mediating bidirectional vacuolar amino acid transport.

    PubMed

    Russnak, R; Konczal, D; McIntire, S L

    2001-06-29

    Seven genes in Saccharomyces cerevisiae are predicted to code for membrane-spanning proteins (designated AVT1-7) that are related to the neuronal gamma-aminobutyric acid-glycine vesicular transporters. We have now demonstrated that four of these proteins mediate amino acid transport in vacuoles. One protein, AVT1, is required for the vacuolar uptake of large neutral amino acids including tyrosine, glutamine, asparagine, isoleucine, and leucine. Three proteins, AVT3, AVT4, and AVT6, are involved in amino acid efflux from the vacuole and, as such, are the first to be shown directly to transport compounds from the lumen of an acidic intracellular organelle. This function is consistent with the role of the vacuole in protein degradation, whereby accumulated amino acids are exported to the cytosol. Protein AVT6 is responsible for the efflux of aspartate and glutamate, an activity that would account for their exclusion from vacuoles in vivo. Transport by AVT1 and AVT6 requires ATP for function and is abolished in the presence of nigericin, indicating that the same pH gradient can drive amino acid transport in opposing directions. Efflux of tyrosine and other large neutral amino acids by the two closely related proteins, AVT3 and AVT4, is similar in terms of substrate specificity to transport system h described in mammalian lysosomes and melanosomes. These findings suggest that yeast AVT transporter function has been conserved to control amino acid flux in vacuolar-like organelles.

  16. [Amino acid level in pastry with low caloric value].

    PubMed

    Barkhatov, V Iu; Vyskubova, N K; Felipas, T B; Pshemurzova, R M; Kamenetskaia, E V

    1988-01-01

    The effect of fruit paste additives on amino acid composition of farinaceous and decorative confectionery semifinished products was studied to decrease their fuel value. It was found that a partial replacement of sugar and fat for apple and quince pastes in apple biscuit and apple shortbread semiproducts led to an increase in the content of essential and sulfur-containing amino acids. Cream prepared from egg albumin and quince paste had reduced content of amino acids (except for glutamic acid) due to the diminished content of egg albumin, however, the balance of amino acid composition was improved.

  17. Siliques Are Red1 from Arabidopsis Acts as a Bidirectional Amino Acid Transporter That Is Crucial for the Amino Acid Homeostasis of Siliques1[W][OA

    PubMed Central

    Ladwig, Friederike; Stahl, Mark; Ludewig, Uwe; Hirner, Axel A.; Hammes, Ulrich Z.; Stadler, Ruth; Harter, Klaus; Koch, Wolfgang

    2012-01-01

    Many membrane proteins are involved in the transport of nutrients in plants. While the import of amino acids into plant cells is, in principle, well understood, their export has been insufficiently described. Here, we present the identification and characterization of the membrane protein Siliques Are Red1 (SIAR1) from Arabidopsis (Arabidopsis thaliana) that is able to translocate amino acids bidirectionally into as well as out of the cell. Analyses in yeast and oocytes suggest a SIAR1-mediated export of amino acids. In Arabidopsis, SIAR1 localizes to the plasma membrane and is expressed in the vascular tissue, in the pericycle, in stamen, and in the chalazal seed coat of ovules and developing seeds. Mutant alleles of SIAR1 accumulate anthocyanins as a symptom of reduced amino acid content in the early stages of silique development. Our data demonstrate that the SIAR1-mediated export of amino acids plays an important role in organic nitrogen allocation and particularly in amino acid homeostasis in developing siliques. PMID:22312005

  18. Catalytic hydrogenation of amino acids to amino alcohols with complete retention of configuration.

    PubMed

    Tamura, Masazumi; Tamura, Riku; Takeda, Yasuyuki; Nakagawa, Yoshinao; Tomishige, Keiichi

    2014-06-25

    Rh-MoOx/SiO2 is an effective heterogeneous catalyst for selective hydrogenation of amino acids to amino alcohols in a water solvent. MoOx modification of Rh drastically enhanced the activity and improved the selectivity and ee. Various amino alcohols were obtained in high yields (90-94%) with complete retention of configuration.

  19. Unprecedented concentrations of indigenous amino acids in primitive CR meteorites

    NASA Astrophysics Data System (ADS)

    Ehrenfreund, Pascale; Martins, Zita; Alexander, Conel; Orzechowska, Grazyna; Fogel, Marylin

    CR meteorites are among the most primitive meteorites. We have performed pioneering work determining the compositional characteristics of amino acids in this type of carbonaceous chondrites. We report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. We have analyzed the amino acid content of the Antarctic CRs EET92042, GRA95229 and GRO95577 using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatography-mass spectrometry (GC-MS). Additionally, compound-specific carbon isotopic measurements for most of the individual amino acids from the EET92042 and GRA95229 meteorites were achieved by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations of 180 and 249 parts-per-million (ppm), respectively. GRO95577, however, is depleted in amino acids (<1 ppm). The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the α-amino acids glycine, isovaline, α-aminoisobutyric acid (α-AIB), and alanine, with δ 13 C values ranging from +31.6% to +50.5%. The highly enriched carbon isotope results together with racemic enantiomeric ratios determined for most amino acids indicate that primitive organic matter was preserved in these meteorites. In addition, the relative abundances of α-AIB and β-alanine amongst Antarctic CR meteorites appear to correspond to the degree of aqueous alteration on their respective parent body. Investigating the abundances and isotopic composition of amino acids in primitive chondrites helps to understand the role of meteorites as a source of extraterrestrial prebiotic organic compounds to the early Earth.

  20. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.

    2009-01-01

    Amino acid analysis of a meteorite fragment of asteroid 2008 TC(sub 3) called Almahata Sitta was carried out using reverse-phase high-perfo rmance liquid chromatography coupled with UV fluorescence detection a nd time-of-flight mass spectrometry (HPLC-FD/ToF-MS) as part of a sam ple analysis consortium. HPLC analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to six-carbon aliph atic amino acids and one- to three carbon amines with abundances rang ing from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, Beta-amino-n-butyric acid (Beta-ABA), 2-amino-2- methylbutanoic acid (isovaline), and 2-aminopentanoic acid (no rvaline) in the meteorite were racemic (D/L approximately 1), indicat ing that these amino acids are indigenous to the meteorite and not te rrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha -aminoisobutyric acid (alpha-AIB), 4-amino-2- methybutanoic acid, 4-a mino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. Th e total abundances of isovaline and AlB in Almahata Sitta are approximately 1000 times lower than the abundances of these amino acids found in the CM carbonaceous meteorite Murchison. The extremely love abund ances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous meteorites and may be due to extensive thermal alteration of amino acids on the parent aster oid by partial melting during formation or impact shock heating.

  1. Nectar amino acids enhance reproduction in male butterflies.

    PubMed

    Cahenzli, Fabian; Erhardt, Andreas

    2013-01-01

    After over 30 years of research, it was recently shown that nectar amino acids increase female butterfly fecundity. However, little attention has been paid to the effect of nectar amino acids on male butterfly reproduction. Here, we show that larval food conditions (nitrogen-rich vs. nitrogen-poor host plants) and adult diet quality (nectar with or without amino acids) affected the amount of consumed nectar in Coenonympha pamphilus males. Furthermore, amino acids in the nectar diet of males increased progeny's larval hatching mass, irrespective of paternal larval reserves. Our study takes the whole reproductive cycle of male butterflies into account, and also considers the role of females in passing male nutrients to offspring, as males' realized reproduction was examined indirectly via nuptial gifts, by female performance. With this comprehensive approach, we demonstrate for the first time that nectar amino acids can improve male butterfly reproduction, supporting the old postulate that nectar amino acids generally enhance butterfly fitness.

  2. Distribution and Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

    Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; McLain, H. L.; Noble, S. K.; Gibson, E. K., Jr.

    2015-01-01

    The existence of organic compounds on the lunar surface has been a question of interest from the Apollo era to the present. Investigations of amino acids immediately after collection of lunar samples yielded inconclusive identifications, in part due to analytical limitations including insensitivity to certain compounds, an inability to separate enantiomers, and lack of compound-specific isotopic measurements. It was not possible to determine if the detected amino acids were indigenous to the lunar samples or the result of terrestrial contamination. Recently, we presented initial data from the analysis of amino acid abundances in 12 lunar regolith samples and discussed those results in the context of four potential amino acid sources [5]. Here, we expand on our previous work, focusing on amino acid abundances and distributions in seven regolith samples and presenting the first compound-specific carbon isotopic ratios measured for amino acids in a lunar sample.

  3. Modulatory Effects of Dietary Amino Acids on Neurodegenerative Diseases.

    PubMed

    Rajagopal, Senthilkumar; Sangam, Supraj Raja; Singh, Shubham; Joginapally, Venkateswara Rao

    2016-01-01

    Proteins are playing a vital role in maintaining the cellular integrity and function, as well as for brain cells. Protein intake and supplementation of individual amino acids can affect the brain functioning and mental health, and many of the neurotransmitters in the brain are made from amino acids. The amino acid supplementation has been found to reduce symptoms, as they are converted into neurotransmitters which in turn extenuate the mental disorders. The biosynthesis of amino acids in the brain is regulated by the concentration of amino acids in plasma. The brain diseases such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder (OCD), and Alzheimer's (AD), Parkinson's (PD), and Huntington's diseases (HD) are the most common mental disorders that are currently widespread in numerous countries. The intricate biochemical and molecular machinery contributing to the neurological disorders is still unknown, and in this chapter, we revealed the involvement of dietary amino acids on neurological diseases.

  4. Surface Propensity of Atmospherically Relevant Amino Acids Studied by XPS.

    PubMed

    Mocellin, Alexandra; Gomes, Anderson Herbert de Abreu; Araújo, Oscar Cardoso; de Brito, Arnaldo Naves; Bjorneholm, Olle

    2017-03-30

    Amino acids constitute an important fraction of the water-soluble organic nitrogen (WSON) compounds in aerosols and are involved in many processes in the atmosphere. In this work, we applied XPS to study aqueous solutions of four amino acids: glycine, alanine, valine and methionine, in their zwitterionic forms. We found that amino acids with hydrophilic side chains and smaller size, GLY and ALA, tend to stay in the bulk of the liquid, while the hydrophobic and bigger amino acids, VAL and MET, are found to concentrate more on the surface. We found experimental evidences that the amino acids have preferential orientation relative to the surface, with the hydrophobic side chain being closer to the surface than the hydrophilic carboxylate group. The observed amino acid surface propensity has implications in atmospheric science as the surface interaction play a central role in cloud droplet formation, and they should be considered in climate models.

  5. Amino acids as chiral selectors in enantioresolution by liquid chromatography.

    PubMed

    Bhushan, Ravi; Dixit, Shuchi

    2012-08-01

    Amino acids are unique in terms of their structural features and multidimensional uses. With their simple structures and the ready availability of both enantiomers, amino acids not only serve as a chiral pool for synthesis but also provide an inexpensive pool for resolution studies. There has been no attempt to review the application of amino acids as chiral selectors for chromatographic enantioresolution of pharmaceuticals and other compounds. The present paper deals with application of l-amino acids and complexes of l-amino acids with a metal ion, particularly Cu(II), as an impregnating reagent in thin-layer chromatography or as a chiral ligand exchange reagent or a chiral mobile phase additive in both thin-layer chromatography and high-performance liquid chromatography. Enantiomeric resolution of β-blockers, nonsteroidal anti-inflammatories, amino acids (and their derivatives) and certain other compounds is discussed.

  6. Geochemistry of amino acids in shells of the clam Saxidomus

    USGS Publications Warehouse

    Kvenvolden, K.A.; Blunt, D.J.; McMenamin, M.A.; Straham, S.E.

    1980-01-01

    Concentrations of amino acids and their corresponding d l enantiomeric ratios have been measured in shells of the bivalve mollusk Saxidomus from eleven localities, ranging in age from modern to probably more than 500,000 yr, along the Pacific coast of North America. Natural logarithms of amino acid concentrations correlate well with d l ratios, and the relationship provides a possible guide to the selection of fossils for use in amino acid dating. The relative order of the extents of racemization of amino acids at any given time appears to change with increasing sample age. Application of the amino acid dating method to shells from Whidbey Island, Washington, yields an age of about 80,000 yr, in contrast to the previously determined radiocarbon age of 36,000 yr which was measured on some shell carbonate and considered a minimum age. The amino acid age is compatible with the geologic record in the area. ?? 1980.

  7. Stereoselective synthesis of stable-isotope-labeled amino acids

    SciTech Connect

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  8. Twenty natural amino acids identification by a photochromic sensor chip.

    PubMed

    Qin, Meng; Li, Fengyu; Huang, Yu; Ran, Wei; Han, Dong; Song, Yanlin

    2015-01-20

    All 20 natural amino acids identification shows crucial importance in biochemistry and clinical application while it is still a challenge due to highly similarity in molecular configuration of the amino acids. Low efficiency, complicated sensing molecules and environment hindered the successful identification. Here, we developed a facile sensor chip composed of one photochromic molecule with metal ions spotted to form spirooxazine-metallic complexes, and successfully recognized all the 20 natural amino acids as well as their mixtures. The sensor chip gives distinct fluorescent fingerprint pattern of each amino acid, based on multistate of spirooxazine under different light stimulations and discriminated interaction between various metal ions and amino acids. The sensor chip demonstrates powerful capability of amino acids identification, which promotes sensing of biomolecules.

  9. Recombinant thiopeptides containing noncanonical amino acids

    PubMed Central

    Luo, Xiaozhou; Zambaldo, Claudio; Liu, Tao; Zhang, Yuhan; Xuan, Weimin; Wang, Chen; Reed, Sean A.; Yang, Peng-Yu; Wang, Rongsheng E.; Javahishvili, Tsotne; Schultz, Peter G.; Young, Travis S.

    2016-01-01

    Thiopeptides are a subclass of ribosomally synthesized and posttranslationally modified peptides (RiPPs) with complex molecular architectures and an array of biological activities, including potent antimicrobial activity. Here we report the generation of thiopeptides containing noncanonical amino acids (ncAAs) by introducing orthogonal amber suppressor aminoacyl-tRNA synthetase/tRNA pairs into a thiocillin producer strain of Bacillus cereus. We demonstrate that thiopeptide variants containing ncAAs with bioorthogonal chemical reactivity can be further postbiosynthetically modified with biophysical probes, including fluorophores and photo-cross-linkers. This work allows the site-specific incorporation of ncAAs into thiopeptides to increase their structural diversity and probe their biological activity; similar approaches can likely be applied to other classes of RiPPs. PMID:26976568

  10. Amino Acid Sensing in Skeletal Muscle.

    PubMed

    Moro, Tatiana; Ebert, Scott M; Adams, Christopher M; Rasmussen, Blake B

    2016-11-01

    Aging impairs skeletal muscle protein synthesis, leading to muscle weakness and atrophy. However, the underlying molecular mechanisms remain poorly understood. Here, we review evidence that mammalian/mechanistic target of rapamycin complex 1 (mTORC1)-mediated and activating transcription factor 4 (ATF4)-mediated amino acid (AA) sensing pathways, triggered by impaired AA delivery to aged skeletal muscle, may play important roles in skeletal muscle aging. Interventions that alleviate age-related impairments in muscle protein synthesis, strength, and/or muscle mass appear to do so by reversing age-related changes in skeletal muscle AA delivery, mTORC1 activity, and/or ATF4 activity. An improved understanding of the mechanisms and roles of AA sensing pathways in skeletal muscle may lead to evidence-based strategies to attenuate sarcopenia.

  11. Synthesis of alpha-amino acids

    DOEpatents

    Davis, J.W. Jr.

    1983-01-25

    A method is described for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R[sub 1]R[sub 2]C(OSOCl)CN, R[sub 1]R[sub 2]C(Cl)CN and [R[sub 1]R[sub 2]C(CN)O][sub 2]SO wherein R[sub 1] and R[sub 2] are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art. No Drawings

  12. Survival of Amino Acids in Micrometeorites During Atmospheric Entry

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Bada, Jeffrey L.

    2003-01-01

    The delivery of amino acids by micrometeorites to the early Earth during the period of heavy bombardment could have been a significant source of the Earth's prebiotic amino acid inventory provided that these organic compounds survived atmospheric entry heating. To investigate the sublimation of amino acids from a micrometeorite analog at elevated temperature, grains from the CM-type carbonaceous chondrite Murchison were heated to 550 C inside a glass sublimation apparatus (SA) under reduced pressure. The sublimed residue that had collected on the cold finger of the SA after heating was analyzed for amino acids by HPLC. We found that when the temperature of the meteorite reached approx. 150 C, a large fraction of the amino acid glycine had vaporized from the meteorite, recondensed onto the end of the SA cold finger, and survived as the rest of the grains heated to 550 C. alpha-Aminoisobutryic acid and isovaline, which are two of the most abundant non-protein amino acids in Murchison, did not sublime from the meteorite and were completely destroyed during the heating experiment. Our experimental results suggest that sublimation of glycine present in micrometeorite grains may provide a way for this amino acid to survive atmospheric entry heating at temperatures less than 550 C; all other amino acids apparently are destroyed. Key Words: Amino acids-Exogenous delivery-Micrometeorites-Sublimation.

  13. Preference for and learning of amino acids in larval Drosophila

    PubMed Central

    Kudow, Nana; Miura, Daisuke; Schleyer, Michael; Toshima, Naoko; Gerber, Bertram

    2017-01-01

    ABSTRACT Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila. PMID:28193602

  14. Preference for and learning of amino acids in larval Drosophila.

    PubMed

    Kudow, Nana; Miura, Daisuke; Schleyer, Michael; Toshima, Naoko; Gerber, Bertram; Tanimura, Teiichi

    2017-03-15

    Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis - and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila. © 2017. Published by The Company of Biologists Ltd.

  15. Diversity of amino acids in a typical chernozem of Moldova

    NASA Astrophysics Data System (ADS)

    Frunze, N. I.

    2014-12-01

    The content and composition of the amino acids in typical chernozems were studied. The objects of the study included a reference soil under an old fallow and three variants under fodder crop rotations: not fertilized, with mineral fertilizers, and with organic fertilizers. The contents of 18 amino acids were determined in these soils. The amino acids were extracted by the method of acid hydrolysis and identified by the method of ion-exchange chromatography. The total content of most of the amino acids was maximal in the reference soil; it was much lower in the cultivated soils and decreased in the following sequence: organic background > mineral background > no fertilization. The diversity of amino acids was evaluated quantitatively using different parameters applied in ecology for estimating various aspects of the species composition of communities (Simpson, Margalef, Menhinick, and Shannon's indices). The diversity and contribution of different amino acids to the total pool of amino acids also varied significantly in the studied variants. The maximum diversity of amino acids and maximum evenness of their relative abundance indices were typical of the reference chernozem; these parameters were lower in the cultivated soils. It was concluded that the changes in the structure of the amino acids under the impact of agricultural loads are similar to those that are usually observed under stress conditions.

  16. Survival of Amino Acids in Micrometeorites During Atmospheric Entry

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Bada, Jeffrey L.

    2003-01-01

    The delivery of amino acids by micrometeorites to the early Earth during the period of heavy bombardment could have been a significant source of the Earth's prebiotic amino acid inventory provided that these organic compounds survived atmospheric entry heating. To investigate the sublimation of amino acids from a micrometeorite analog at elevated temperature, grains from the CM-type carbonaceous chondrite Murchison were heated to 550 C inside a glass sublimation apparatus (SA) under reduced pressure. The sublimed residue that had collected on the cold finger of the SA after heating was analyzed for amino acids by HPLC. We found that when the temperature of the meteorite reached approx. 150 C, a large fraction of the amino acid glycine had vaporized from the meteorite, recondensed onto the end of the SA cold finger, and survived as the rest of the grains heated to 550 C. alpha-Aminoisobutryic acid and isovaline, which are two of the most abundant non-protein amino acids in Murchison, did not sublime from the meteorite and were completely destroyed during the heating experiment. Our experimental results suggest that sublimation of glycine present in micrometeorite grains may provide a way for this amino acid to survive atmospheric entry heating at temperatures less than 550 C; all other amino acids apparently are destroyed. Key Words: Amino acids-Exogenous delivery-Micrometeorites-Sublimation.

  17. Chemoenzymatic synthesis of surfactants from carbohydrates, amino acids, and fatty acids.

    PubMed

    Bellahouel, S; Rolland, V; Roumestant, M L; Viallefont, P; Martinez, J

    2001-02-01

    The chemoenzymatic synthesis of new surfactants is reported; they were prepared from unprotected carbohydrates, amino acids, and fatty acids. This study pointed out the factors that govern the possibility to enzymatically bind the carbohydrate to the amino acid.

  18. The Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K., Jr.

    2016-01-01

    We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.

  19. Trophic spectra under the lens of amino acid isotopic analysis

    USDA-ARS?s Scientific Manuscript database

    Recent advances in compound specific isotopic ratio analysis (CSIRA) have allowed researchers to measure trophic fractionation of 15N in specific amino acids, namely glutamic acid and phenylalanine. These amino acids have proven useful in food web studies because of the wide and consistent disparity...

  20. The Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K., Jr.

    2016-01-01

    We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.

  1. Urinary excretion of N-acetyl amino acids in patients with some inborn errors of amino acid metabolism.

    PubMed

    Jellum, E; Horn, L; Thoresen, O; Kvittingen, E A; Stokke, O

    1986-01-01

    Urinary organic acid profiles of patients with Maple Syrup Urine Disease (MSUD), hereditary tyrosinemia and phenylketonuria (PKU) have been studied by means of capillary GC-MS-computer technique. In addition to the characteristic metabolites of these disorders, increased amounts of N-acetylleucine, N-acetylisoleucine and N-acetylvaline were found in MSUD-urine. Increased excretion of N-acetylphenylalanine occurred in PKU, and in tyrosinemia both the latter compound and increased N-acetyltyrosine excretion were observed. These results together with literature reports of similar studies on patients with other aminoacidopathies may indicate that most disorders which result in accumulation of one or more specific amino acids, will convert a small fraction of them into their corresponding N-acetyl derivative.

  2. Understanding and identifying amino acid repeats

    PubMed Central

    Nijveen, Harm

    2014-01-01

    Amino acid repeats (AARs) are abundant in protein sequences. They have particular roles in protein function and evolution. Simple repeat patterns generated by DNA slippage tend to introduce length variations and point mutations in repeat regions. Loss of normal and gain of abnormal function owing to their variable length are potential risks leading to diseases. Repeats with complex patterns mostly refer to the functional domain repeats, such as the well-known leucine-rich repeat and WD repeat, which are frequently involved in protein–protein interaction. They are mainly derived from internal gene duplication events and stabilized by ‘gate-keeper’ residues, which play crucial roles in preventing inter-domain aggregation. AARs are widely distributed in different proteomes across a variety of taxonomic ranges, and especially abundant in eukaryotic proteins. However, their specific evolutionary and functional scenarios are still poorly understood. Identifying AARs in protein sequences is the first step for the further investigation of their biological function and evolutionary mechanism. In principle, this is an NP-hard problem, as most of the repeat fragments are shaped by a series of sophisticated evolutionary events and become latent periodical patterns. It is not possible to define a uniform criterion for detecting and verifying various repeat patterns. Instead, different algorithms based on different strategies have been developed to cope with different repeat patterns. In this review, we attempt to describe the amino acid repeat-detection algorithms currently available and compare their strategies based on an in-depth analysis of the biological significance of protein repeats. PMID:23418055

  3. Interactions between homopolymeric amino acids (HPAAs).

    PubMed

    Oma, Yoko; Kino, Yoshihiro; Toriumi, Kazuya; Sasagawa, Noboru; Ishiura, Shoichi

    2007-10-01

    Many human proteins contain consecutive amino acid repeats, known as homopolymeric amino acid (HPAA) tracts. Some inherited diseases are caused by proteins in which HPAAs are expanded to an excessive length. To this day, nine polyglutamine-related diseases and nine polyalanine-related diseases have been reported, including Huntington's disease and oculopharyngeal muscular dystrophy. In this study, potential HPAA-HPAA interactions were examined by yeast two-hybrid assays using HPAAs of approximately 30 residues in length. The results indicate that hydrophobic HPAAs interact with themselves and with other hydrophobic HPAAs. Previously, we reported that hydrophobic HPAAs formed large aggregates in COS-7 cells. Here, those HPAAs were shown to have significant interactions with each other, suggesting that hydrophobicity plays an important role in aggregation. Among the observed HPAA-HPAA interactions, the Ala28-Ala29 interaction was notable because polyalanine tracts of these lengths have been established to be pathogenic in several polyalanine-related diseases. By testing several constructs of different lengths, we clarified that polyalanine self-interacts at longer lengths (>23 residues) but not at shorter lengths (six to approximately 23 residues) in a yeast two-hybrid assay and a GST pulldown assay. This self-interaction was found to be SDS sensitive in SDS-PAGE and native-PAGE assays. Moreover, the intracellular localization of these long polyalanine tracts was also observed to be disturbed. Our results suggest that long tracts of polyalanine acquire SDS-sensitive self-association properties, which may be a prerequisite event for their abnormal folding. The misfolding of these tracts is thought to be a common molecular aspect underlying the pathogenesis of polyalanine-related diseases.

  4. Interactions between homopolymeric amino acids (HPAAs)

    PubMed Central

    Oma, Yoko; Kino, Yoshihiro; Toriumi, Kazuya; Sasagawa, Noboru; Ishiura, Shoichi

    2007-01-01

    Many human proteins contain consecutive amino acid repeats, known as homopolymeric amino acid (HPAA) tracts. Some inherited diseases are caused by proteins in which HPAAs are expanded to an excessive length. To this day, nine polyglutamine-related diseases and nine polyalanine-related diseases have been reported, including Huntington's disease and oculopharyngeal muscular dystrophy. In this study, potential HPAA–HPAA interactions were examined by yeast two-hybrid assays using HPAAs of ∼30 residues in length. The results indicate that hydrophobic HPAAs interact with themselves and with other hydrophobic HPAAs. Previously, we reported that hydrophobic HPAAs formed large aggregates in COS-7 cells. Here, those HPAAs were shown to have significant interactions with each other, suggesting that hydrophobicity plays an important role in aggregation. Among the observed HPAA–HPAA interactions, the Ala28–Ala29 interaction was notable because polyalanine tracts of these lengths have been established to be pathogenic in several polyalanine-related diseases. By testing several constructs of different lengths, we clarified that polyalanine self-interacts at longer lengths (>23 residues) but not at shorter lengths (six to ∼23 residues) in a yeast two-hybrid assay and a GST pulldown assay. This self-interaction was found to be SDS sensitive in SDS-PAGE and native-PAGE assays. Moreover, the intracellular localization of these long polyalanine tracts was also observed to be disturbed. Our results suggest that long tracts of polyalanine acquire SDS-sensitive self-association properties, which may be a prerequisite event for their abnormal folding. The misfolding of these tracts is thought to be a common molecular aspect underlying the pathogenesis of polyalanine-related diseases. PMID:17766374

  5. Influence of light on the free amino acid content and γ-aminobutyric acid synthesis in Brassica juncea seedlings.

    PubMed

    Li, Xiaohua; Kim, Yeon Bok; Uddin, Md Romij; Lee, Sanghyun; Kim, Sun-Ju; Park, Sang Un

    2013-09-11

    Glutamate decarboxylase (GAD; EC 4.1.1.15) is an important enzyme in γ-aminobutyric acid (GABA) biosynthesis. Here we report the influence of light on amino acid accumulation and investigate the molecular mechanism by which light influences GABA biosynthesis at the seedling stage of two mustard (Brassica juncea) cultivars (green-leaf and purple-leaf). Gene expression profiles of four GAD-encoding genes (GAD1, GAD2, GAD4a, and GAD4b) and their impact on GABA biosynthesis were analyzed. Light exerted an obvious influence on amino acid accumulation in mustard seedlings. GAD gene expression was also significantly regulated by light/dark or dark treatment, which differentially regulated GABA biosynthesis in B. juncea seedlings. High-performance liquid chromatography (HPLC) revealed that the seeds of purple cultivars contain a higher amount of free amino acids and GABA than do the seeds of green cultivars. After seed germination, however, the accumulation of free amino acids peaked in dark-treated seedlings on day 9 in both cultivars, whereas GABA synthesis peaked at 9 days under light conditions. This study may provide a foundation for understanding the effect of light on amino acids, particularly GABA biosynthesis in Brassica plants.

  6. Amino Acid Export in Developing Arabidopsis Seeds Depends on UmamiT Facilitators.

    PubMed

    Müller, Benedikt; Fastner, Astrid; Karmann, Julia; Mansch, Verena; Hoffmann, Thomas; Schwab, Wilfried; Suter-Grotemeyer, Marianne; Rentsch, Doris; Truernit, Elisabeth; Ladwig, Friederike; Bleckmann, Andrea; Dresselhaus, Thomas; Hammes, Ulrich Z

    2015-12-07

    Essential amino acids cannot be synthesized by humans and animals. They often are limiting in plant-derived foods and determine the nutritional value of a given diet. Seeds and fruits often represent the harvestable portion of plants. In order to improve the amino acid composition of these tissues, it is indispensable to understand how these substrates are transported within the plant. Amino acids result from nitrogen assimilation, which often occurs in leaves, the source tissue. They are transported via the vasculature, the xylem, and the phloem into the seeds, the so-called sink tissue, where they are stored or consumed. In seeds, several tissues are symplasmically isolated, i.e., not connected by plasmodesmata, channels in the cell walls that enable a cytoplasmic continuum in plants. Consequently, amino acids must be exported from cells into the apoplast and re-imported many times to support seed development. Several amino acid importers are known, but exporters remained elusive. Here, we characterize four members of the plant-specific UmamiT transporter family from Arabidopsis, related to the amino acid facilitator SIAR1 and the vacuolar auxin transporter WAT1. We show that the proteins transport amino acids along their (electro)chemical potential across the plasma membrane. In seeds, they are found in tissues from which amino acids are exported. Loss-of-function mutants accumulate high levels of free amino acids in fruits and produce smaller seeds. Our results strongly suggest a crucial role for the UmamiTs in amino acid export and possibly a means to improve yield quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Amino acids of the Murchison meteorite. II - Five carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Pizzarello, S.; Yuen, G. U.

    1985-01-01

    The five-carbon acyclic primary beta, gamma, and delta amino alkanoic acids of the Murchison meteorite are studied using gas chromatography-mass spectrometry and ion exchange chromatography. The chromatograms reveal that alpha is the most abundant monoamino alkanoic acid followed by gamma and beta, and an exponential increase in the amount of amino acid is observed as the carbon number increases in the homologous series. The influence of frictional heating, spontaneous thermal decomposition, and radiation of the synthesis of amino acids is examined. The data obtained support an amino acid synthesis process involving random combination of single-carbon precursors.

  8. A molecular biological approach to reducing dietary amino acid needs.

    PubMed

    Rees, W D; Flint, H J; Fuller, M F

    1990-07-01

    Rapid developments in transgenic animal technology make it possible to consider introducing new metabolic capabilities into animals, using genes from other species. Lysine and threonine are both essential amino acids in mammals, and are commonly the first and second limiting amino acids, respectively, for protein accretion in pigs and poultry fed cereal based diets. Here we consider the potential for transgenic animals with microbial biosynthetic pathways for these amino acids.

  9. [Detection of amino acids based on terahertz spectroscopy].

    PubMed

    Tang, Zhong-feng; Lin, Hai-tao; Chen, Xiao-wei; Zhang, Zeng-fang

    2009-09-01

    Terahertz (THz) is the frequency region ranging from 0.1 to 2.0 THz, which lies in the far-infrared region. Compared to Fourier transform infrared spectra (FTIR), terahertz time-domain spectra (THz-TDS) has low energy, high signal-to-noise ratio (SNR) and is non-ionizing radiation. Low-frequency vibrational modes of some amino acids, such as torsional and collective vibrational modes and hydrogen-bond modes, exist in the THz region. Amino acids are important organic compounds and are the fundamental components of proteins. Amino acids can exist with a highly ordered crystal structure linked by hydrogen intermolecular bonds in the solid phase. The absorption spectra of amino acids in the THz region show marked differences while mid-infrared absorption spectra usually show very little difference. Up to now, absorption spectra of twenty kinds of amino acids have been studied by many researchers using THz technique; the quantitative analysis of amino acids by THZ-TDS is also included. Investigation of THz spectra of amino acids are of fundamental interests, and will lead to further understanding of low-frequency vibrations of protein/DNA and relevant biological reactions and activities. In the present paper, the latest progress in absorption spectra of amino acids determined by THz spectroscopy is reviewed and a database is built. Some brief remarks on future developments in and prospects for THz application in amino acids are also provided.

  10. Amino acids in the cultivation of mammalian cells.

    PubMed

    Salazar, Andrew; Keusgen, Michael; von Hagen, Jörg

    2016-05-01

    Amino acids are crucial for the cultivation of mammalian cells. This importance of amino acids was realized soon after the development of the first cell lines, and a solution of a mixture of amino acids has been supplied to cultured cells ever since. The importance of amino acids is further pronounced in chemically defined mammalian cell culture media, making the consideration of their biological and chemical properties necessary. Amino acids concentrations have been traditionally adjusted to their cellular consumption rates. However, since changes in the metabolic equilibrium of amino acids can be caused by changes in extracellular concentrations, metabolomics in conjunction with flux balance analysis is being used in the development of culture media. The study of amino acid transporters is also gaining importance since they control the intracellular concentrations of these molecules and are influenced by conditions in cell culture media. A better understanding of the solubility, stability, dissolution kinetics, and interactions of these molecules is needed for an exploitation of these properties in the development of dry powdered chemically defined media for mammalian cells. Due to the complexity of these mixtures however, this has proven to be challenging. Studying amino acids in mammalian cell culture media will help provide a better understanding of how mammalian cells in culture interact with their environment. It would also provide insight into the chemical behavior of these molecules in solutions of complex mixtures, which is important in the understanding of the contribution of individual amino acids to protein structure.

  11. Recent advances in microchip electrophoresis for amino acid analysis.

    PubMed

    Ou, Gaozhi; Feng, Xiaojun; Du, Wei; Liu, Xin; Liu, Bi-Feng

    2013-10-01

    With the maturation of microfluidic technologies, microchip electrophoresis has been widely employed for amino acid analysis owing to its advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. In this article, we review the recent progress in amino acid analysis using microchip electrophoresis during the period from 2007 to 2012. Innovations in microchip materials, surface modification, sample introduction, microchip electrophoresis, and detection methods are documented, as well as nascent applications of amino acid analysis in single-cell analysis, microdialysis sampling, food analysis, and extraterrestrial exploration. Without doubt, more applications of microchip electrophoresis in amino acid analysis may be expected soon.

  12. The amino acid sequence of wood duck lysozyme.

    PubMed

    Araki, T; Torikata, T

    1999-01-01

    The amino acid sequence of wood duck (Aix sponsa) lysozyme was analyzed. Carboxymethylated lysozyme was digested with trypsin and the resulting peptides were sequenced. The established amino acid sequence had the highest similarity to duck III lysozyme with four amino acid substitutions, and had eighteen amino acid substitutions from chicken lysozyme. The valine at position 75 was newly detected in chicken-type lysozymes. In the active site, Tyr34 and Glu57 were found at subsites F and D, respectively, when compared with chicken lysozyme.

  13. Use of free amino acid composition of shell to estimate age since death of recent molluscs

    SciTech Connect

    Logan, A.M.; Powell, E.N.; Stanton, R.J. Jr.

    1985-01-01

    An understanding of death assemblage formation requires a measurement of time since death of constituent individuals. A new dating technique based on the measurement of the free amino acid content of mollusc shells has been developed which is inexpensive, rapid, and effective in dating time scales of a few decades to a few centuries. Since the breakdown of proteins of the matrix of mollusc shells begins soon after deposition, free amino acids gradually increase with shell age. The measurement of these can be used to determine the relative age among a group of shells. The future use of this technique depends on a clearer understanding of how free amino acid accumulation rate varies with age and species and developing effective calibration methods so that absolute rather than relative ages can be readily obtained. Three species were distributed widely enough for use - Rangia cuneata, Tagelus plebeius, and Phacoides pectinatus. A good relationship between free amino acids and relative age was present in all three species over the entire core; however some species and some amino acid were superior to others. Rangia cuneata produced the best correlation because it is epifaunal and thus died at the sediment surface rather than over an extended depth range and, also perhaps, because amino acid accumulation rates were more linear.

  14. Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120.

    PubMed

    Pernil, Rafael; Picossi, Silvia; Herrero, Antonia; Flores, Enrique; Mariscal, Vicente

    2015-04-23

    Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS) family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB) was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter) was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.

  15. Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

    PubMed Central

    Pernil, Rafael; Picossi, Silvia; Herrero, Antonia; Flores, Enrique; Mariscal, Vicente

    2015-01-01

    Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS) family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB) was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter) was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion. PMID:25915115

  16. [Nutritional and ecological aspects of the uptake of dissolved amino acids by Anemonia sulcata (Coelenterata, Anthozoa)].

    PubMed

    Schlichter, Dietrich

    1973-12-01

    Anemonia sulcata resorbs and accumulates tritiated L-amino acids dissolved in sea water in their natural concentrations (70-700 nmol/l).Resorption takes place mainly through the apical membrane of the ectoderm. Even after quite long periods of exposure autoradiography reveals that the amino acids resorbed are located in the ectoderm; this is attributable to its cytological structure. Electronmicrographs show that only the ectoderm bears microvilli.The rate uptake (2-10 μg/g wet weight/h) depends on the type of the amino acid and its concentration.The concentration below which only a very slight degree of uptake is detected ranges from 10-100 nmol/l for the different amino acids.Certain amino acids (phe, lys, leu, his, pro) are used mainly in metabolic synthesis. Others (gly, ser) are also used in oxidative processes, as indicated by the presence of tritium water which results from the oxidation of (3)H-amino acids.The concentration of free amino acids in tentacle tissue has been analyzed. The concentration of glycine, for example, is greater by a factor of 10(7) in tissue than in the medium in which resorption takes place, showing that uptake is an active process.Calculation reveals that the actinians satisfy a substantial proportion of their metabolic requirements by resorbing organic material from the environment.

  17. New insights into the regulation of plant immunity by amino acid metabolic pathways.

    PubMed

    Zeier, Jürgen

    2013-12-01

    Besides defence pathways regulated by classical stress hormones, distinct amino acid metabolic pathways constitute integral parts of the plant immune system. Mutations in several genes involved in Asp-derived amino acid biosynthetic pathways can have profound impact on plant resistance to specific pathogen types. For instance, amino acid imbalances associated with homoserine or threonine accumulation elevate plant immunity to oomycete pathogens but not to pathogenic fungi or bacteria. The catabolism of Lys produces the immune signal pipecolic acid (Pip), a cyclic, non-protein amino acid. Pip amplifies plant defence responses and acts as a critical regulator of plant systemic acquired resistance, defence priming and local resistance to bacterial pathogens. Asp-derived pyridine nucleotides influence both pre- and post-invasion immunity, and the catabolism of branched chain amino acids appears to affect plant resistance to distinct pathogen classes by modulating crosstalk of salicylic acid- and jasmonic acid-regulated defence pathways. It also emerges that, besides polyamine oxidation and NADPH oxidase, Pro metabolism is involved in the oxidative burst and the hypersensitive response associated with avirulent pathogen recognition. Moreover, the acylation of amino acids can control plant resistance to pathogens and pests by the formation of protective plant metabolites or by the modulation of plant hormone activity.

  18. Amino acid fermentation at the origin of the genetic code

    PubMed Central

    2012-01-01

    There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments

  19. In vitro quantitative analysis of Salmonella typhimurium preference for amino acids secreted by human breast tumor

    NASA Astrophysics Data System (ADS)

    Choi, Eunpyo; Maeng, Bohee; Lee, Jae-hun; Chang, Hyung-kwan; Park, Jungyul

    2016-12-01

    Bacterial therapies have been paid significant attentions by their ability to penetrate deep into the solid tumor tissue and its propensity to naturally accumulate in tumors of living animals. Understanding the actual mechanism for bacteria to target the tumor is therapeutically crucial but is poorly understood. We hypothesized that amino acids released from the specific tumors induced bacteria to those tumors and the experiments for chemotactic response of bacteria toward the cancer secreting amino acids was then performed by using the diffusion based multiple chemical gradient generator constructed by in situ self-assembly of microspheres. The quantitative analysis was carried out by comparison of intensity using green fluorescent protein (GFP) tagged Salmonella typhimurium ( S. typhimurium) in the gradient generator, which showed the clear preference to the released amino acids, especially from breast cancer patients. The understanding chemotaxis toward the cancer secreting amino acids is essential for controlling S. typhimurium targeting in tumors and will allow for the development of bacterial therapies.

  20. Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids

    SciTech Connect

    Standaert, Robert F; Park, Dr Seung Bum

    2006-01-01

    Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A in the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.

  1. Receptor-level interrelationships of amino acids and the adequate amino acid type hormones in Tetrahymena: a receptor evolution model.

    PubMed

    Csaba, G; Darvas, Z

    1986-01-01

    Histidine stimulates the phagocytosis of Tetrahymena to the same extent as histamine, and also stimulates its division, which histamine does not. Tyrosine and diiodotyrosine equally stimulate the growth of the Tetrahymena. Both amino acids inhibit the characteristic influence of the adequate amino acid hormone when added to Tetrahymena culture 72 h in advance of it. Primary interaction with diiodotyrosine and tyrosine notably increases the cellular growth rate. Histamine has a similar, although less notable effect than histidine. In the light of these experimental observations there is reason to postulate that the receptors of the amino acid hormones have developed from amino acid receptors.

  2. The amino acid composition of proteins from anaerobic halophilic bacteria of the order Halanaerobiales.

    PubMed

    Elevi Bardavid, Rahel; Oren, Aharon

    2012-05-01

    We performed a comparative analysis of the genome sequences of three anaerobic halophilic fermentative bacteria belonging to the order Halanaerobiales: Halanaerobium praevalens, the alkaliphilic "Halanaerobium hydrogeniformans", and the thermophilic Halothermothrix orenii to assess the amino acid composition of their proteins. Members of the Halanaerobiales were earlier shown to accumulate KCl rather than organic compatible solutes for osmotic balance, and therefore the presence of a dominantly acidic proteome was predicted. Past reports indeed showed a large excess of acidic over basic amino acids in whole-cell hydrolysates of selected members of the order. However, the genomic analysis did not show unusually high contents of acidic amino acids or low contents of basic amino acids. The apparent excess of acidic amino acids in these anaerobic halophiles reported earlier is due to the high content in their proteins of glutamine and asparagine, which yield glutamate and aspartate upon acid hydrolysis. It is thus suggested that the proteins of the Halanaerobiales, which are active in the presence of high intracellular KCl concentrations, do not possess the typical acidic signature of the 'halophilic' proteins of the Archaea of the order Halobacteriales or of the extremely halophilic bacterium Salinibacter.

  3. Preferential Treatment: Interaction Between Amino Acids and Minerals

    NASA Astrophysics Data System (ADS)

    Crapster-Pregont, E. J.; Cleaves, H. J.; Hazen, R. M.

    2008-12-01

    Amino acids are the building blocks of proteins and are important for some models of the origin of life. Polymerization of amino acids from dilute solution is unlikely without a scaffold or catalyst. The surfaces of early Earth minerals are the most likely candidates for this role. The surface adsorption behavior of 12 amino acids (L-alanine, L-serine, L-aspartic acid, L-proline, L- phenylalanine, L-valine, L-arginine, d-amino valeric acid, glycine, L-lysine, L-isoleucine, and B-alanine) on 21 minerals (quartz, calcite, enstatite, illite, olivine, pyrrhotite, pyrite, alkali basalt, albite, analcime, chlorite, barite, hydroxyl apatite, hematite, magnetite, aluminum hydroxide, kaolin, silica gel, corundum, rutile, and montmorillonite) was determined via batch adsorption experiments. Absorption was determined for concentrations between 10-4M and 10-6M in the presence of 0.1M NaCl, and between pH values of 3 and 9 at 25 degrees C. The equilibrated solutions were centrifuged, filtered, derivatized using a fluorescent amino group tag (dansyl-chloride) and analyzed by HPLC. Adsorption was standardized using BET surface area measurements for each mineral to give the number of mols of each amino acid adsorbed per square meter for each mineral. The results indicate an enormous difference in the adsorption of amino acids between minerals, along with major differences in the adsorption of individual amino acids on the same mineral surface. There is also a change in the absorbance of amino acids as the pH changes. Many previous studies of amino acid concentration and catalysis by minerals have used clay minerals because of their high surface areas, however, this data suggests that the surfaces of minerals such as calcite, quartz and pyrite have even higher affinities for amino acids. The results suggest mineral surfaces that could be optimal locations for the polymerization of molecules linked to the origin of life.

  4. Amino Acid Availability Modulates Vacuolar H+-ATPase Assembly*

    PubMed Central

    Stransky, Laura A.; Forgac, Michael

    2015-01-01

    The vacuolar H+-ATPase (V-ATPase) is an ATP-dependent proton pump composed of a peripheral ATPase domain (V1) and a membrane-integral proton-translocating domain (V0) and is involved in many normal and disease processes. An important mechanism of regulating V-ATPase activity is reversible assembly of the V1 and V0 domains. Increased assembly in mammalian cells occurs under various conditions and has been shown to involve PI3K. The V-ATPase is necessary for amino acid-induced activation of mechanistic target of rapamycin complex 1 (mTORC1), which is important in controlling cell growth in response to nutrient availability and growth signals. The V-ATPase undergoes amino acid-dependent interactions with the Ragulator complex, which is involved in recruitment of mTORC1 to the lysosomal membrane during amino acid sensing. We hypothesized that changes in the V-ATPase/Ragulator interaction might involve amino acid-dependent changes in V-ATPase assembly. To test this, we measured V-ATPase assembly by cell fractionation in HEK293T cells treated with and without amino acids. V-ATPase assembly increases upon amino acid starvation, and this effect is reversed upon readdition of amino acids. Lysosomes from amino acid-starved cells possess greater V-ATPase-dependent proton transport, indicating that assembled pumps are catalytically active. Amino acid-dependent changes in both V-ATPase assembly and activity are independent of PI3K and mTORC1 activity, indicating the involvement of signaling pathways distinct from those implicated previously in controlling assembly. By contrast, lysosomal neutralization blocks the amino acid-dependent change in assembly and reactivation of mTORC1 after amino acid starvation. These results identify an important new stimulus for controlling V-ATPase assembly. PMID:26378229

  5. Amino acids regulate transgene expression in MDCK cells.

    PubMed

    Torrente, Marta; Guetg, Adriano; Sass, Jörn Oliver; Arps, Lisa; Ruckstuhl, Lisa; Camargo, Simone M R; Verrey, François

    2014-01-01

    Gene expression and cell growth rely on the intracellular concentration of amino acids, which in metazoans depends on extracellular amino acid availability and transmembrane transport. To investigate the impact of extracellular amino acid concentrations on the expression of a concentrative amino acid transporter, we overexpressed the main kidney proximal tubule luminal neutral amino acid transporter B0AT1-collectrin (SLC6A19-TMEM27) in MDCK cell epithelia. Exogenously expressed proteins co-localized at the luminal membrane and mediated neutral amino acid uptake. However, the transgenes were lost over few cell culture passages. In contrast, the expression of a control transgene remained stable. To test whether this loss was due to inappropriately high amino acid uptake, freshly transduced MDCK cell lines were cultivated either with physiological amounts of amino acids or with the high concentration found in standard cell culture media. Expression of exogenous transporters was unaffected by physiological amino acid concentration in the media. Interestingly, mycoplasma infection resulted in a significant increase in transgene expression and correlated with the rapid metabolism of L-arginine. However, L-arginine metabolites were shown to play no role in transgene expression. In contrast, activation of the GCN2 pathway revealed by an increase in eIF2α phosphorylation may trigger transgene derepression. Taken together, high extracellular amino acid concentration provided by cell culture media appears to inhibit the constitutive expression of concentrative amino acid transporters whereas L-arginine depletion by mycoplasma induces the expression of transgenes possibly via stimulation of the GCN2 pathway.

  6. Amino Acids Regulate Transgene Expression in MDCK Cells

    PubMed Central

    Torrente, Marta; Guetg, Adriano; Sass, Jörn Oliver; Arps, Lisa; Ruckstuhl, Lisa; Camargo, Simone M. R.; Verrey, François

    2014-01-01

    Gene expression and cell growth rely on the intracellular concentration of amino acids, which in metazoans depends on extracellular amino acid availability and transmembrane transport. To investigate the impact of extracellular amino acid concentrations on the expression of a concentrative amino acid transporter, we overexpressed the main kidney proximal tubule luminal neutral amino acid transporter B0AT1-collectrin (SLC6A19-TMEM27) in MDCK cell epithelia. Exogenously expressed proteins co-localized at the luminal membrane and mediated neutral amino acid uptake. However, the transgenes were lost over few cell culture passages. In contrast, the expression of a control transgene remained stable. To test whether this loss was due to inappropriately high amino acid uptake, freshly transduced MDCK cell lines were cultivated either with physiological amounts of amino acids or with the high concentration found in standard cell culture media. Expression of exogenous transporters was unaffected by physiological amino acid concentration in the media. Interestingly, mycoplasma infection resulted in a significant increase in transgene expression and correlated with the rapid metabolism of L-arginine. However, L-arginine metabolites were shown to play no role in transgene expression. In contrast, activation of the GCN2 pathway revealed by an increase in eIF2α phosphorylation may trigger transgene derepression. Taken together, high extracellular amino acid concentration provided by cell culture media appears to inhibit the constitutive expression of concentrative amino acid transporters whereas L-arginine depletion by mycoplasma induces the expression of transgenes possibly via stimulation of the GCN2 pathway. PMID:24797296

  7. Utilization of acidic α-amino acids as acyl donors: an effective stereo-controllable synthesis of aryl-keto α-amino acids and their derivatives.

    PubMed

    Wang, Lei; Murai, Yuta; Yoshida, Takuma; Okamoto, Masashi; Tachrim, Zetryana Puteri; Hashidoko, Yasuyuki; Hashimoto, Makoto

    2014-05-16

    Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

  8. Synthesis of gold nanoparticles using various amino acids.

    PubMed

    Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya

    2015-06-01

    Gold nanoparticles (4-7nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl4(-) solution with an amino acid at 80°C for 20min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solutions varied with the amino acids used for the reduction. We adopted l-histidine as a reducing agent and investigated the effects of the synthesis conditions on the gold nanoparticles. The His and AuCl4(-) concentrations affected the size of the gold nanoparticles and their aggregates. The pH of the reaction solution also affected the reaction yields and the shape of the gold nanoparticles.

  9. Polysulfone affinity membranes for the treatment of amino acid mixtures.

    PubMed

    Rodemann, K; Staude, E

    1995-06-20

    Affinity membranes for the treatment of solutions containing amino acids were obtained via lithiating polysulfone that was subsequently converted with glycidylether. From this polymer asymmetric ultrafiltration membranes were cast. The membranes were reacted with iminodiacetic acid yielding membranes fitted out with bidentate chelates. The same reaction path was applied to commercially available symmetric microfiltration membranes. The chelate-bearing membranes were complexed with Cu, Ni, and Zn ions. For the experiments with amino acids only the Cu-complexed membranes were used. The complexation constants for histidine and tryptophan for six different membranes were determined. Because of the affinity of these two amino acids for the complexed Cu ions, they could easily be separated from solutions containing amino acids such as alanine, glycine, and valine. Also, concentrating very dilute amino acid solutions was carried out successfully.

  10. Free amino acids in botanicals and botanical preparations.

    PubMed

    Carratù, B; Boniglia, C; Giammarioli, S; Mosca, M; Sanzini, E

    2008-06-01

    Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and gamma-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.

  11. Adsorption of amino acids by fullerenes and fullerene nanowhiskers

    NASA Astrophysics Data System (ADS)

    Hashizume, Hideo; Hirata, Chika; Fujii, Kazuko; Miyazawa, Kun'ichi

    2015-12-01

    We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C60) and fullerene nanowhiskers (FNWs). C60 and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C60 or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C60 did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C60 and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C60 and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C60 and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C60. The theoretical simulations showed the bonding distance between C60 and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C60 showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C60. In our study Try and Tyr were hardly adsorbed by C60 and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.

  12. Adsorption of amino acids by fullerenes and fullerene nanowhiskers.

    PubMed

    Hashizume, Hideo; Hirata, Chika; Fujii, Kazuko; Miyazawa, Kun'ichi

    2015-12-01

    We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C60) and fullerene nanowhiskers (FNWs). C60 and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C60 or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C60 did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C60 and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C60 and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C60 and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C60. The theoretical simulations showed the bonding distance between C60 and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C60 showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C60. In our study Try and Tyr were hardly adsorbed by C60 and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.

  13. Amino acid biogeochemistry and organic matter degradation state across the Pakistan margin oxygen minimum zone

    NASA Astrophysics Data System (ADS)

    Vandewiele, Sandra; Cowie, Greg; Soetaert, Karline; Middelburg, Jack J.

    2009-03-01

    To assess whether the oxygen minimum zone (OMZ) across the Pakistan Margin causes differences in the lability of sedimentary organic matter, sediments were collected in the core of the OMZ, in the upper and lower transition zones and below the OMZ. Sediment samples were analysed for total nitrogen (TN) and organic carbon (OC) contents, mineral surface area (SA), and total hydrolysable amino acids (THAA) and enzymatically hydrolysable amino acids (EHAA). OC contents and organic carbon per unit of mineral surface area (OC/SA) values were clearly elevated in the core and lower OMZ transition zone. These sediments also contained more labile sedimentary organic matter, as discerned by higher concentrations of THAA and the contribution of N in THAA to TN. A protein amino acid-based degradation index revealed that all sedimentary organic matter has undergone significant degradation, but sediments in the upper OMZ transition zone and below the OMZ are more degraded than inside the OMZ. Changes in amino acid composition during diagenesis are attributed to a combination of factors: (1) selective preservation in which amino acids in cell walls are better preserved than amino acids in cell plasma, (2) formation and accumulation of bacterially derived organic matter; there were relatively more living bacteria in the core of the OMZ and an accumulation of peptidoglycan-derived amino acids in degraded sediments in the upper OMZ transition zone and below the OMZ, and (3) bacterial transformation, as the molar percentages of bacterial transformation products β-alanine (Bala), γ-amino butyric acid (Gaba), and ornithine (Orn), increased with increasing degradation.

  14. Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides

    NASA Astrophysics Data System (ADS)

    Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

    2007-09-01

    Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  15. Bromine accumulation in acidic black colluvial soils

    NASA Astrophysics Data System (ADS)

    Cortizas, Antonio Martínez; Vázquez, Cruz Ferro; Kaal, Joeri; Biester, Harald; Casais, Manuela Costa; Rodríguez, Teresa Taboada; Lado, Luis Rodríguez

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (<50 μm) fraction were on average 3-times higher than those (17-250 μg g-1) in the fine earth (<2 mm), the former containing almost all bromine (90 ± 5%). Inventories were between 148 and 314 g m-2, indicating a rather large variability in a small area, and total estimated retention was low (6-16%). The degree of SOM bromination, expressed as the Br/C molar ratio, varied between 0.03 and 1.20 mmol Br/mol C. The ratio was highly correlated (n = 23, r2 0.88, p < 0.01) with the age of the SOM for the last ∼12 ka. Partial least squares modeling indicates that bromine concentration depends on the amount of organic matter stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

  16. Terrestrial evolution of polymerization of amino acids - Heat to ATP

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Nakashima, T.

    1981-01-01

    Sets of amino acids containing sufficient trifunctional monomer are thermally polymerized at temperatures such as 65 deg; the amino acids order themselves. Various polymers have diverse catalytic activities. The polymers aggregate, in aqueous solution, to cell-like structures having those activities plus emergent properties, e.g. proliferatability. Polyamino acids containing sufficient lysine catalyze conversion of free amino acids, by ATP, to small peptides and a high molecular weight fraction. The lysine-rich proteinoid is active in solution, within suspensions of cell-like particles, or in other particles composed of lysine-rich proteinoid and homopolyribonucleotide. Selectivities are observed. An archaic polyamino acid prelude to coded protein synthesis is indicated.

  17. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  18. The Path of Carbon in Photosynthesis II. Amino Acids

    DOE R&D Accomplishments Database

    Stepka, W.; Benson, A. A.; Calvin, M.

    1948-05-25

    The radioactive amino acid's synthesized from C{sup 14}O{sub 2} by green algae both in the light and in the dark after CO{sub 2}-free preillumination have been separated and identified using paper chromatography and radioautography. The radioactive amino acids identified were aspartic acid, alanine and smaller amounts of 3- and 4-carbon amino acids. This finding as well as the total absence of radioactive glutamic acid substantiates the mechanism for reduction of CO{sub 2} previously postulated by members of this laboratory.

  19. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  20. Fatty acid and amino acid modulation of glucose cycling in isolated rat hepatocytes.

    PubMed Central

    Gustafson, L A; Neeft, M; Reijngoud, D J; Kuipers, F; Sauerwein, H P; Romijn, J A; Herling, A W; Burger, H J; Meijer, A J

    2001-01-01

    We studied the influence of glucose/glucose 6-phosphate cycling on glycogen deposition from glucose in fasted-rat hepatocytes using S4048 and CP320626, specific inhibitors of glucose-6-phosphate translocase and glycogen phosphorylase respectively. The effect of amino acids and oleate was also examined. The following observations were made: (1) with glucose alone, net glycogen production was low. Inhibition of glucose-6-phosphate translocase increased intracellular glucose 6-phosphate (3-fold), glycogen accumulation (5-fold) without change in active (dephosphorylated) glycogen synthase (GSa) activity, and lactate production (4-fold). With both glucose 6-phosphate translocase and glycogen phosphorylase inhibited, glycogen deposition increased 8-fold and approached reported in vivo rates of glycogen deposition during the fasted-->fed transition. Addition of a physiological mixture of amino acids in the presence of glucose increased glycogen accumulation (4-fold) through activation of GS and inhibition of glucose-6-phosphatase flux. Addition of oleate with glucose present decreased glycolytic flux and increased the flux through glucose 6-phosphatase with no change in glycogen deposition. With glucose 6-phosphate translocase inhibited by S4048, oleate increased intracellular glucose 6-phosphate (3-fold) and net glycogen production (1.5-fold), without a major change in GSa activity. It is concluded that glucose cycling in hepatocytes prevents the net accumulation of glycogen from glucose. Amino acids activate GS and inhibit flux through glucose-6-phosphatase, while oleate inhibits glycolysis and stimulates glucose-6-phosphatase flux. Variation in glucose 6-phosphate does not always result in activity changes of GSa. Activation of glucose 6-phosphatase flux by fatty acids may contribute to the increased hepatic glucose production as seen in Type 2 diabetes. PMID:11535127

  1. Amino Acid Racemization and the Preservation of Ancient DNA

    NASA Technical Reports Server (NTRS)

    Poinar, Hendrik N.; Hoss, Matthias

    1996-01-01

    The extent of racemization of aspartic acid, alanine, and leucine provides criteria for assessing whether ancient tissue samples contain endogenous DNA. In samples in which the D/L ratio of aspartic acid exceeds 0.08, ancient DNA sequences could not be retrieved. Paleontological finds from which DNA sequences purportedly millions of years old have been reported show extensive racemization, and the amino acids present are mainly contaminates. An exception is the amino acids in some insects preserved in amber.

  2. Amino Acids in Nectar Enhance Longevity of Female Culex quinquefasciatus

    DTIC Science & Technology

    2010-01-01

    and that some insects show a preference for carbohydrate sources containing amino acids (Alm et al., 1990; Mevi-Schutz and Erhardt, 2003b), has led...to an increased interest in the role that they play in insect life histories (Baker and Baker, 1973). Some insects rely on nectar as a primary source ...2003a; Hill and Pierce, 1989). Certain flowers contain high levels of amino acids, and have been studied as potentially important sources for amino

  3. Boron containing amino acid compounds and methods for their use

    DOEpatents

    Glass, John D.; Coderre, Jeffrey A.

    2000-01-01

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  4. BAT1, a bidirectional amino acid transporter in Arabidopsis.

    PubMed

    Dündar, Ekrem; Bush, Daniel R

    2009-04-01

    The Arabidopsis thaliana At2g01170 gene is annotated as a putative gamma amino butyric acid (GABA) permease based on its sequence similarity to a yeast GABA transporting gene (UGA4). A cDNA of At2g01170 was expressed in yeast and analyzed for amino acid transport activity. Both direct measurement of amino acid transport and yeast growth experiments demonstrated that the At2g01170 encoded-protein exhibits transport activity for alanine, arginine, glutamate and lysine, but not for GABA or proline. Significantly, unlike other amino acid transporters described in plants to date, At2g01170 displayed both export and import activity. Based on that observation, it was named bidirectional amino acid transporter 1 (BAT1). Sequence comparisons show BAT1 is not a member of any previously defined amino acid transporter family. It does share, however, several conserved protein domains found in a variety of prokaryotic and eukaryotic amino acid transporters, suggesting membership in an ancient family of transporters. BAT1 is a single copy gene in the Arabidopsis genome, and its mRNA is ubiquitously expressed in all organs. A transposon--GUS gene-trap insert in the BAT1 gene displays GUS localization in the vascular tissues (Dundar in Ann Appl Biol, 2009) suggesting BAT1 may function in amino acid export from the phloem into sink tissues.

  5. Site specific incorporation of keto amino acids into proteins

    DOEpatents

    Schultz, Peter G [La Jolla, CA; Wang, Lei [San Diego, CA

    2008-10-07

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  6. Site specific incorporation of keto amino acids into proteins

    DOEpatents

    Schultz, Peter G [La Jolla, CA; Wang, Lei [San Diego, CA

    2011-03-22

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  7. Production of amino acids using auxotrophic mutants of methylotrophic bacillus

    DOEpatents

    Hanson, Richard S.; Flickinger, Michael C.; Schendel, Frederick J.; Guettler, Michael V.

    2001-07-17

    A method of producing amino acids by culturing an amino acid auxotroph of a biologically pure strain of a type I methylotrophic bacterium of the genus Bacillus which exhibits sustained growth at 50.degree. C. using methanol as a carbon and energy source and requiring vitamin B.sub.12 and biotin is provided.

  8. Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

    NASA Astrophysics Data System (ADS)

    Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves, H. James, II

    2015-03-01

    Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or ``chemistry space.'' Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set.

  9. Site specific incorporation of keto amino acids into proteins

    SciTech Connect

    Schultz, Peter G; Wang, Lei

    2012-02-14

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  10. Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

    PubMed Central

    Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves II, H. James

    2015-01-01

    Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or “chemistry space.” Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set. PMID:25802223

  11. Site specific incorporation of keto amino acids into proteins

    SciTech Connect

    Schultz, Peter G; Wang, Lei

    2011-12-06

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  12. Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie E.; Aponte, Jose C.; Blackmond, Donna G.; Burton, Aaron S.; Dworkin, Jason P.; Glavin, Daniel P.

    2016-01-01

    The analysis of amino acids in meteorites dates back over 50 years; however, it is only in recent years that research has expanded beyond investigations of a narrow set of meteorite groups (exemplied by the Murchison meteorite) into meteorites of other types and classes. These new studies have shown a wide diversity in the abundance and distribution of amino acids across carbonaceous chondrite groups, highlighting the role of parent body processes and composition in the creation, preservation, or alteration of amino acids. Although most chiral amino acids are racemic in meteorites, the enantiomeric distribution of some amino acids, particularly of the nonprotein amino acid isovaline, has also been shown to vary both within certain meteorites and across carbonaceous meteorite groups. Large -enantiomeric excesses of some extraterrestrial protein amino acids (up to 60) have also been observed in rare cases and point to nonbiological enantiomeric enrichment processes prior to the emergence of life. In this Outlook, we review these recent meteoritic analyses, focusing on variations in abundance, structural distributions, and enantiomeric distributions of amino acids and discussing possible explanations for these observations and the potential for future work.

  13. Parenteral sulfur amino acid requirements in septic infants

    USDA-ARS?s Scientific Manuscript database

    To investigate parenteral methionine requirements of critically ill, septic infants, we conducted an investigation involving 12 infants (age 2+/-1 years; weight 13+/-2kg) using the intravenous indicator amino acid oxidation and balance technique. They received a balanced parenteral amino acid formul...

  14. Amino acid determination in some edible Mexican insects.

    PubMed

    Ladrón de Guevara, O; Padilla, P; García, L; Pino, J M; Ramos-Elorduy, J

    1995-06-01

    The amino acid contents of edible insects from different provinces of Mexico and reference proteins were analysed by reversed-phase high-performance liquid chromatography and ion exchange chromatography. The insect amino acid contents were higher than the adult requirements indicated by the WHO/FAO pattern.

  15. Site-selective covalent reactions on proteinogenic amino acids.

    PubMed

    So, Wing Ho; Zhang, Yu; Kang, Wei; Wong, Clarence T T; Sun, Hongyan; Xia, Jiang

    2017-07-05

    To achieve precise control of the signaling events or to achieve unmistakable synthesis of biomolecules, nature has evolved organic reactions involving proteinogenic amino acids with unparalleled site selectivity. For example, dedicated enzymes accurately dictate the site of post-translational modifications in signaling proteins, and ribosomes precisely link the C-terminal carboxylic acid of one unprotected amino acid with the N-terminal amino group of the other amino acid through spatially confined proximity. For many years, chemists have been striving to achieve site selectivity on biomolecules by mimicking nature. Driven by the development of chemoselective protein conjugation reactions, enzymology and protein-protein interactions, the past decade has witnessed a boom in site-selective protein conjugation reactions. (In this review, a site-selective protein conjugation reaction is defined as an organic reaction that targets a single amino acid instead of a kind of amino acids in a protein or a proteome under physiological conditions, for example, a single cysteine residue among all of the cysteines.) In this review, we summarize the recent advancements of bioconjugation reactions that demonstrate this feature of precise site selectivity, focusing on the reactions of the proteinogenic amino acids (excluding those at non-coded or non-proteinogenic amino acids that are introduced to proteins through genetic manipulations). Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Natural toxins that affect plant amino acid metabolism

    USDA-ARS?s Scientific Manuscript database

    A diverse range of natural compounds interfere with the synthesis and other aspects of amino acid metabolism. Some are amino acid analogues, but most are not. This review covers a number of specific natural phytotoxic compounds by molecular target site. Inhibition of glutamine synthetase is of part...

  17. Site specific incorporation of keto amino acids into proteins

    DOEpatents

    Schultz, Peter G.; Wang, Lei

    2009-04-28

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  18. Interactive Hangman Teaches Amino Acid Structures and Abbreviations

    ERIC Educational Resources Information Center

    Pennington, Britney O.; Sears, Duane; Clegg, Dennis O.

    2014-01-01

    We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying…

  19. Deaminative and decarboxylative catalytic alkylation of amino acids with ketones.

    PubMed

    Kalutharage, Nishantha; Yi, Chae S

    2013-12-16

    It cuts two ways: The cationic [Ru-H] complex catalyzes selective coupling of α- and β-amino acids with ketones to form α-alkylated ketone products. The reaction involves CC and CN bond cleavage which result in regio- and stereoselective alkylation using amino acids. A broad substrate scope and high functional-group tolerance is demonstrated.

  20. Interactive Hangman Teaches Amino Acid Structures and Abbreviations

    ERIC Educational Resources Information Center

    Pennington, Britney O.; Sears, Duane; Clegg, Dennis O.

    2014-01-01

    We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying…

  1. Boron containing amino acid compounds and methods for their use

    SciTech Connect

    Glass, J.D.; Coderre, J.A.

    2000-01-25

    The present invention provides new boron containing amino acid compounds and methods for making these compounds by contacting melphalan or another nitrogen mustard derivative and sodium borocaptate. The present invention also provides a method of treating a mammal having a tumor by administering to the mammal a therapeutically effective amount of the new boron containing amino acid compounds.

  2. Parenteral amino acid intakes in critically ill children

    USDA-ARS?s Scientific Manuscript database

    Parenteral amino acid formulas used in parenteral nutrition have a variable composition. To determine the amino acid intake of parenterally fed, critically ill children, and compare it with recommended dietary allowances (RDA) established by the Institute of Medicine (IOM), we retrospectively review...

  3. Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories

    PubMed Central

    2016-01-01

    The analysis of amino acids in meteorites dates back over 50 years; however, it is only in recent years that research has expanded beyond investigations of a narrow set of meteorite groups (exemplified by the Murchison meteorite) into meteorites of other types and classes. These new studies have shown a wide diversity in the abundance and distribution of amino acids across carbonaceous chondrite groups, highlighting the role of parent body processes and composition in the creation, preservation, or alteration of amino acids. Although most chiral amino acids are racemic in meteorites, the enantiomeric distribution of some amino acids, particularly of the nonprotein amino acid isovaline, has also been shown to vary both within certain meteorites and across carbonaceous meteorite groups. Large l-enantiomeric excesses of some extraterrestrial protein amino acids (up to ∼60%) have also been observed in rare cases and point to nonbiological enantiomeric enrichment processes prior to the emergence of life. In this Outlook, we review these recent meteoritic analyses, focusing on variations in abundance, structural distributions, and enantiomeric distributions of amino acids and discussing possible explanations for these observations and the potential for future work. PMID:27413780

  4. Amino acids in a carbonaceous chondrite from Antarctica

    NASA Technical Reports Server (NTRS)

    Kotra, R. K.; Shimoyama, A.; Ponnamperuma, C.; Hare, P. E.

    1979-01-01

    A carbonaceous chondrite from the Antarctic, referred to as the Allan Hills meteorite 77306, appears to be free from terrestrial organic contamination. The presence of both protein and non-protein amino acids and an equal abundance of D- and L-enantiomers of amino acids, is testimony to the extraterrestrial nature of these compounds.

  5. Comparison of Free Total Amino Acid Compositions and Their Functional Classifications in 13 Wild Edible Mushrooms.

    PubMed

    Sun, Liping; Liu, Qiuming; Bao, Changjun; Fan, Jian

    2017-02-24

    Thirteen popular wild edible mushroom species in Yunnan Province, Boletus bicolor, Boletus speciosus, Boletus sinicus, Boletus craspedius, Boletus griseus, Boletus ornatipes, Xerocomus, Suillus placidus, Boletinus pinetorus, Tricholoma terreum, Tricholomopsis lividipileata, Termitomyces microcarpus, and Amanita hemibapha, were analyzed for their free amino acid compositions by online pre-column derivazation reversed phase high-performance liquid chromatography (RP-HPLC) analysis. Twenty free amino acids, aspartic acid, glutamic acid, serine, glycine, alanine, praline, cysteine, valine, methionine, phenylalanine, isoleucine, leucine, lysine, histidine, threonine, asparagines, glutamine, arginine, tyrosine, and tryptophan, were determined. The total free amino acid (TAA) contents ranged from 1462.6 mg/100 g in B. craspedius to 13,106.2 mg/100 g in T. microcarpus. The different species showed distinct free amino acid profiles. The ratio of total essential amino acids (EAA) to TAA was 0.13-0.41. All of the analyzed species showed high contents of hydrophobic amino acids, at 33%-54% of TAA. Alanine, cysteine, glutamine, and glutamic acid were among the most abundant amino acids present in all species. The results showed that the analyzed mushrooms possessed significant free amino acid contents, which may be important compounds contributing to the typical mushroom taste, nutritional value, and potent antioxidant properties of these wild edible mushrooms. Furthermore, the principal component analysis (PCA) showed that the accumulative variance contribution rate of the first four principal components reached 94.39%. Cluster analysis revealed EAA composition and content might be an important parameter to separate the mushroom species, and T. microcarpus and A. hemibapha showed remarkable EAA content among the 13 species.

  6. Amino Acid Carbamates As Prodrugs Of Resveratrol.

    PubMed

    Mattarei, Andrea; Azzolini, Michele; La Spina, Martina; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia

    2015-10-14

    Resveratrol (3, 5, 4'-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) linkage with a natural amino acid (Leu, Ile, Phe, Thr) to prevent conjugation and modulate the physicochemical properties of the molecule. We also report a convenient, high-yield protocol to obtain derivatives of this type. The new carbamate ester derivatives are stable at pH 1, while they undergo slow hydrolysis at physiological pH and hydrolyse with kinetics suitable for use in prodrugs in whole blood. After administration to rats by oral gavage the isoleucine-containing prodrug was significantly absorbed, and was present in the bloodstream as non-metabolized unaltered or partially deprotected species, demonstrating effective shielding from first-pass metabolism. We conclude that prodrugs based on the N-monosubstituted carbamate ester bond have the appropriate stability profile for the systemic delivery of phenolic compounds.

  7. Marine Planktonic Archaea Take Up Amino Acids

    PubMed Central

    Ouverney, Cleber C.; Fuhrman, Jed A.

    2000-01-01

    Archaea are traditionally thought of as “extremophiles,” but recent studies have shown that marine planktonic Archaea make up a surprisingly large percentage of ocean midwater microbial communities, up to 60% of the total prokaryotes. However, the basic physiology and contribution of Archaea to community microbial activity remain unknown. We have studied Archaea from 200-m depths of the northwest Mediterranean Sea and the Pacific Ocean near California, measuring the archaeal activity under simulated natural conditions (8 to 17°C, dark and anaerobic) by means of a method called substrate tracking autoradiography fluorescence in situ hybridization (STARFISH) that simultaneously detects specific cell types by 16S rRNA probe binding and activity by microautoradiography. In the 200-m-deep Mediterranean and Pacific samples, cells binding the archaeal probes made up about 43 and 14% of the total countable cells, respectively. Our results showed that the Archaea are active in the uptake of dissolved amino acids from natural concentrations (nanomolar) with about 60% of the individuals in the archaeal communities showing measurable uptake. Bacteria showed a similar proportion of active cells. We concluded that a portion of these Archaea is heterotrophic and also appears to coexist successfully with Bacteria in the same water. PMID:11055931

  8. Amino acids: metabolism, functions, and nutrition.

    PubMed

    Wu, Guoyao

    2009-05-01

    Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.

  9. Electronic coupling through natural amino acids

    SciTech Connect

    Berstis, Laura; Beckham, Gregg T. E-mail: gregg.beckham@nrel.gov; Crowley, Michael F. E-mail: gregg.beckham@nrel.gov

    2015-12-14

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green’s function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  10. Electronic coupling through natural amino acids

    NASA Astrophysics Data System (ADS)

    Berstis, Laura; Beckham, Gregg T.; Crowley, Michael F.

    2015-12-01

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green's function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  11. The tangled bank of amino acids

    PubMed Central

    Pollock, David D.

    2016-01-01

    Abstract The use of amino acid substitution matrices to model protein evolution has yielded important insights into both the evolutionary process and the properties of specific protein families. In order to make these models tractable, standard substitution matrices represent the average results of the evolutionary process rather than the underlying molecular biophysics and population genetics, treating proteins as a set of independently evolving sites rather than as an integrated biomolecular entity. With advances in computing and the increasing availability of sequence data, we now have an opportunity to move beyond current substitution matrices to more interpretable mechanistic models with greater fidelity to the evolutionary process of mutation and selection and the holistic nature of the selective constraints. As part of this endeavour, we consider how epistatic interactions induce spatial and temporal rate heterogeneity, and demonstrate how these generally ignored factors can reconcile standard substitution rate matrices and the underlying biology, allowing us to better understand the meaning of these substitution rates. Using computational simulations of protein evolution, we can demonstrate the importance of both spatial and temporal heterogeneity in modelling protein evolution. PMID:27028523

  12. How Do Haloarchaea Synthesize Aromatic Amino Acids?

    PubMed Central

    Gulko, Miriam Kolog; Dyall-Smith, Mike; Gonzalez, Orland; Oesterhelt, Dieter

    2014-01-01

    Genomic analysis of H. salinarum indicated that the de novo pathway for aromatic amino acid (AroAA) biosynthesis does not follow the classical pathway but begins from non-classical precursors, as is the case for M. jannaschii. The first two steps in the pathway were predicted to be carried out by genes OE1472F and OE1475F, while the 3rd step follows the canonical pathway involving gene OE1477R. The functions of these genes and their products were tested by biochemical and genetic methods. In this study, we provide evidence that supports the role of proteins OE1472F and OE1475F catalyzing consecutive enzymatic reactions leading to the production of 3-dehydroquinate (DHQ), after which AroAA production proceeds via the canonical pathway starting with the formation of DHS (dehydroshikimate), catalyzed by the product of ORF OE1477R. Nutritional requirements and AroAA uptake studies of the mutants gave results that were consistent with the proposed roles of these ORFs in AroAA biosynthesis. DNA microarray data indicated that the 13 genes of the canonical pathway appear to be utilised for AroAA biosynthesis in H. salinarum, as they are differentially expressed when cells are grown in medium lacking AroAA. PMID:25216252

  13. Amino acid composition predicts prion activity.

    PubMed

    Afsar Minhas, Fayyaz Ul Amir; Ross, Eric D; Ben-Hur, Asa

    2017-04-10

    Many prion-forming proteins contain glutamine/asparagine (Q/N) rich domains, and there are conflicting opinions as to the role of primary sequence in their conversion to the prion form: is this phenomenon driven primarily by amino acid composition, or, as a recent computational analysis suggested, dependent on the presence of short sequence elements with high amyloid-forming potential. The argument for the importance of short sequence elements hinged on the relatively-high accuracy obtained using a method that utilizes a collection of length-six sequence elements with known amyloid-forming potential. We weigh in on this question and demonstrate that when those sequence elements are permuted, even higher accuracy is obtained; we also propose a novel multiple-instance machine learning method that uses sequence composition alone, and achieves better accuracy than all existing prion prediction approaches. While we expect there to be elements of primary sequence that affect the process, our experiments suggest that sequence composition alone is sufficient for predicting protein sequences that are likely to form prions. A web-server for the proposed method is available at http://faculty.pieas.edu.pk/fayyaz/prank.html, and the code for reproducing our experiments is available at http://doi.org/10.5281/zenodo.167136.

  14. Amino Acid Carbamates As Prodrugs Of Resveratrol

    PubMed Central

    Mattarei, Andrea; Azzolini, Michele; La Spina, Martina; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia

    2015-01-01

    Resveratrol (3, 5, 4′-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) linkage with a natural amino acid (Leu, Ile, Phe, Thr) to prevent conjugation and modulate the physicochemical properties of the molecule. We also report a convenient, high-yield protocol to obtain derivatives of this type. The new carbamate ester derivatives are stable at pH 1, while they undergo slow hydrolysis at physiological pH and hydrolyse with kinetics suitable for use in prodrugs in whole blood. After administration to rats by oral gavage the isoleucine-containing prodrug was significantly absorbed, and was present in the bloodstream as non-metabolized unaltered or partially deprotected species, demonstrating effective shielding from first-pass metabolism. We conclude that prodrugs based on the N-monosubstituted carbamate ester bond have the appropriate stability profile for the systemic delivery of phenolic compounds. PMID:26463125

  15. Amino Acid Analyses of Acid Hydrolysates in Desert Varnish

    NASA Technical Reports Server (NTRS)

    Perry, Randall S.; Staley, James T.; Dworkin, Jason P.; Engel, Mike

    2001-01-01

    There has long been a debate as to whether rock varnish deposits are microbially mediated or are deposited by inorganic processes. Varnished rocks are found throughout the world primarily in arid and semi-arid regions. The varnish coats are typically up to 200 microns thick and are composed of clays and alternating layers enriched in manganese and iron oxides. The individual layers range in thickness from 1 micron to greater than 10 microns and may continue laterally for more than a 100 microns. Overlapping botryoidal structures are visible in thin section and scanning electron micrographs. The coatings also include small amounts of organic mater and detrital grains. Amino-acid hydrolysates offer a means of assessing the organic composition of rock varnish collected from the Sonoran Desert, near Phoenix, AZ. Chromatographic analyses of hydrolysates from powdered samples of rock varnish suggest that the interior of rock varnish is relatively enriched in amino acids and specifically in d-alanine and glutamic acid. Peptidoglycan (murein) is the main structural component of gram-positive bacterial cell walls. The d-enantiomer of alanine and glutamic acid are specific to peptidoglycan and are consequently an indicator for the presence of bacteria. D-alanine is also found in teichoic acid which is only found in gram-positive bacteria. Several researchers have cultured bacteria from the surface of rock varnish and most have been gram-positive, suggesting that gram-positive bacteria are intimately associated with varnish coatings and may play a role in the formation of varnish coatings.

  16. Amino Acid Analyses of Acid Hydrolysates in Desert Varnish

    NASA Technical Reports Server (NTRS)

    Perry, Randall S.; Staley, James T.; Dworkin, Jason P.; Engel, Mike

    2001-01-01

    There has long been a debate as to whether rock varnish deposits are microbially mediated or are deposited by inorganic processes. Varnished rocks are found throughout the world primarily in arid and semi-arid regions. The varnish coats are typically up to 200 microns thick and are composed of clays and alternating layers enriched in manganese and iron oxides. The individual layers range in thickness from 1 micron to greater than 10 microns and may continue laterally for more than a 100 microns. Overlapping botryoidal structures are visible in thin section and scanning electron micrographs. The coatings also include small amounts of organic mater and detrital grains. Amino-acid hydrolysates offer a means of assessing the organic composition of rock varnish collected from the Sonoran Desert, near Phoenix, AZ. Chromatographic analyses of hydrolysates from powdered samples of rock varnish suggest that the interior of rock varnish is relatively enriched in amino acids and specifically in d-alanine and glutamic acid. Peptidoglycan (murein) is the main structural component of gram-positive bacterial cell walls. The d-enantiomer of alanine and glutamic acid are specific to peptidoglycan and are consequently an indicator for the presence of bacteria. D-alanine is also found in teichoic acid which is only found in gram-positive bacteria. Several researchers have cultured bacteria from the surface of rock varnish and most have been gram-positive, suggesting that gram-positive bacteria are intimately associated with varnish coatings and may play a role in the formation of varnish coatings.

  17. Evolutionary patterns of amino acid substitutions in 12 Drosophila genomes

    PubMed Central

    2010-01-01

    Background Harnessing vast amounts of genomic data in phylogenetic context stemming from massive sequencing of multiple closely related genomes requires new tools and approaches. We present a tool for the genome-wide analysis of frequencies and patterns of amino acid substitutions in multiple alignments of genes’ coding regions, and a database of amino acid substitutions in the phylogeny of 12 Drosophila genomes. We illustrate the use of these resources to address three types of evolutionary genomics questions: about fluxes in amino acid composition in proteins, about asymmetries in amino acid substitutions and about patterns of molecular evolution in duplicated genes. Results We demonstrate that amino acid composition of Drosophila proteins underwent a significant shift over the last 70 million years encompassed by the studied phylogeny, with less common amino acids (Cys, Met, His) increasing in frequency and more common ones (Ala, Leu, Glu) becoming less frequent. These fluxes are strongly correlated with polarity of source and destination amino acids, resulting in overall systematic decrease of mean polarity of amino acids found in Drosophila proteins. Frequency and radicality of amino acid substitutions are higher in paralogs than in orthologous single-copy genes and are higher in gene families with paralogs than in gene families without surviving duplications. Rate and radicality of substitutions, as expected, are negatively correlated with overall level and uniformity of gene expression. However, these correlations are not observed for substitutions occurring in duplicated genes, indicating a different selective constraint on the evolution of paralogous sequences. Clades resulting from duplications show a marked asymmetry in rate and radicality of amino acid substitutions, possibly a signal of widespread neofunctionalization. These patterns differ among protein families of different functionality, with genes coding for RNA-binding proteins differing from

  18. Interaction of metal ions and amino acids - Possible mechanisms for the adsorption of amino acids on homoionic smectite clays

    NASA Technical Reports Server (NTRS)

    Gupta, A.; Loew, G. H.; Lawless, J.

    1983-01-01

    A semiempirical molecular orbital method is used to characterize the binding of amino acids to hexahydrated Cu(2+) and Ni(2+), a process presumed to occur when they are adsorbed in the interlamellar space of homoionic smectite clays. Five alpha-amino acids, beta-alanine, and gamma-aminobutyric acid were used to investigate the metal ion and amino acid specificity in binding. It was assumed that the alpha, beta, and gamma-amino acids would bind as bidentate anionic ligands, forming either 1:1 or 1:2 six-coordinated five, six, and seven-membered-ring chelate complexes, respectively. Energies of complex formation, optimized geometries, and electron and spin distribution were determined; and steric constraints of binding of the amino acids to the ion-exchanged cations in the interlamellar spacing of a clay were examined. Results indicate that hexahydrated Cu(2+) forms more stable complexes than hexahydrated Ni(2+) with all the amino acids studied. However, among these amino acids, complex formation does not favor the adsorption of the biological subset. Calculated energetics of complex formation and steric constraints are shown to predict that 1:1 rather than 1:2 metal-amino acid complexes are generally favored in the clay.

  19. Interaction of metal ions and amino acids - Possible mechanisms for the adsorption of amino acids on homoionic smectite clays

    NASA Technical Reports Server (NTRS)

    Gupta, A.; Loew, G. H.; Lawless, J.

    1983-01-01

    A semiempirical molecular orbital method is used to characterize the binding of amino acids to hexahydrated Cu(2+) and Ni(2+), a process presumed to occur when they are adsorbed in the interlamellar space of homoionic smectite clays. Five alpha-amino acids, beta-alanine, and gamma-aminobutyric acid were used to investigate the metal ion and amino acid specificity in binding. It was assumed that the alpha, beta, and gamma-amino acids would bind as bidentate anionic ligands, forming either 1:1 or 1:2 six-coordinated five, six, and seven-membered-ring chelate complexes, respectively. Energies of complex formation, optimized geometries, and electron and spin distribution were determined; and steric constraints of binding of the amino acids to the ion-exchanged cations in the interlamellar spacing of a clay were examined. Results indicate that hexahydrated Cu(2+) forms more stable complexes than hexahydrated Ni(2+) with all the amino acids studied. However, among these amino acids, complex formation does not favor the adsorption of the biological subset. Calculated energetics of complex formation and steric constraints are shown to predict that 1:1 rather than 1:2 metal-amino acid complexes are generally favored in the clay.

  20. Concentration variations of amino acids in mammalian fossils: effects of diagenesis and the implications for amino acid racemization analysis

    SciTech Connect

    Blackwell, B.; Rutter, N.W.

    1985-01-01

    Detailed amino acid analysis of bones, teeth, and antler from several mammal species have shown that concentrations of several amino acids can be related to three factors: type of material analyzed, diagenetic alteration of the material, and relative age of the fossil. Concentrations of several amino acids are significantly different in enamel compared to those of dentine or cement. This can be used to check that no contamination of one material by another has occurred, which is critical for using the data for amino acid dating, since all three materials have different racemization rates for some acids. With increased in growth of secondary minerals, generally reduced amino acid concentrations are observed. Interacid ratios and concentrations vary significantly the norms expected for the type of material with increasing degrees of alteration. These effects can be linked to abnormal racemization ratios observed in the same samples. Therefore, abnormal concentrations and/or interacid ratios can be used to detect samples in which the D/L amino acid ratios otherwise appear normal, thereby insuring better accuracy of amino acid racemization analysis. For unaltered fossils, with increasing sample age regardless the type of material, some amino acids steadily degrade, while others actually increase in concentration initially due to their generation as by-products of decay. Preliminary studies indicate that this progressive alteration can used to complement racemization data for determining relative stratigraphic sequences.

  1. Supernovae, Neutrinos and the Chirality of Amino Acids

    PubMed Central

    Boyd, Richard N.; Kajino, Toshitaka; Onaka, Takashi

    2011-01-01

    A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the 14N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth’s proteinaceous amino acids. PMID:21747686

  2. Supernovae, neutrinos and the chirality of amino acids.

    PubMed

    Boyd, Richard N; Kajino, Toshitaka; Onaka, Takashi

    2011-01-01

    A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the (14)N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's proteinaceous amino acids.

  3. Essential role for collectrin in renal amino acid transport.

    PubMed

    Danilczyk, Ursula; Sarao, Renu; Remy, Christine; Benabbas, Chahira; Stange, Gerti; Richter, Andreas; Arya, Sudha; Pospisilik, J Andrew; Singer, Dustin; Camargo, Simone M R; Makrides, Victoria; Ramadan, Tamara; Verrey, Francois; Wagner, Carsten A; Penninger, Josef M

    2006-12-21

    Angiotensin -converting enzyme 2 (ACE2) is a regulator of the renin angiotensin system involved in acute lung failure, cardiovascular functions and severe acute respiratory syndrome (SARS) infections in mammals. A gene encoding a homologue to ACE2, termed collectrin (Tmem27), has been identified in immediate proximity to the ace2 locus. The in vivo function of collectrin was unclear. Here we report that targeted disruption of collectrin in mice results in a severe defect in renal amino acid uptake owing to downregulation of apical amino acid transporters in the kidney. Collectrin associates with multiple apical transporters and defines a novel group of renal amino acid transporters. Expression of collectrin in Xenopus oocytes and Madin-Darby canine kidney (MDCK) cells enhances amino acid transport by the transporter B(0)AT1. These data identify collectrin as a key regulator of renal amino acid uptake.

  4. Stardust, Supernovae and the Chirality of the Amino Acids

    SciTech Connect

    Boyd, R N; Kajino, T; Onaka, T

    2011-03-09

    A mechanism for creating enantiomerism in the amino acids, the building blocks of the proteins, that involves global selection of one chirality by interactions between the amino acids and neutrinos from core-collapse supernovae is described. The selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the 14N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's amino acids.

  5. Amino Acids Are an Ineffective Fertilizer for Dunaliella spp. Growth

    PubMed Central

    Murphree, Colin A.; Dums, Jacob T.; Jain, Siddharth K.; Zhao, Chengsong; Young, Danielle Y.; Khoshnoodi, Nicole; Tikunov, Andrey; Macdonald, Jeffrey; Pilot, Guillaume; Sederoff, Heike

    2017-01-01

    Autotrophic microalgae are a promising bioproducts platform. However, the fundamental requirements these organisms have for nitrogen fertilizer severely limit the impact and scale of their cultivation. As an alternative to inorganic fertilizers, we investigated the possibility of using amino acids from deconstructed biomass as a nitrogen source in the genus Dunaliella. We found that only four amino acids (glutamine, histidine, cysteine, and tryptophan) rescue Dunaliella spp. growth in nitrogen depleted media, and that supplementation of these amino acids altered the metabolic profile of Dunaliella cells. Our investigations revealed that histidine is transported across the cell membrane, and that glutamine and cysteine are not transported. Rather, glutamine, cysteine, and tryptophan are degraded in solution by a set of oxidative chemical reactions, releasing ammonium that in turn supports growth. Utilization of biomass-derived amino acids is therefore not a suitable option unless additional amino acid nitrogen uptake is enabled through genetic modifications of these algae. PMID:28603530

  6. Transport of Amino Acids to the Maize Root 1

    PubMed Central

    Oaks, Ann

    1966-01-01

    When 5-mm maize root tips were excised and placed in an inorganic salts solution for 6 hours, there was a loss of alcohol-insoluble nitrogen. The levels of threonine, proline, valine, isoleucine, leucine, tyrosine, phenylalanine, and lysine in the alcohol soluble fraction were severely reduced, whereas those of glutamate, aspartate, ornithine, and alanine were scarcely affected. There was a 4-fold increase in the level of γ-aminobutyrate. Those amino acids whose synthesis appeared to be deficient in excised root tips also showed poor incorporation of acetate carbon. In addition, the results show that asparagine and the amino acids of the neutral and basic fraction were preferentially transported to the root tip region. The results therefore suggest that the synthesis of certain amino acids in the root tip region is restricted, and that this requirement for amino acids in the growing region could regulate the flow of amino acids to the root tip. PMID:16656225

  7. Peptide and amino acid separation with nanofiltration membranes

    SciTech Connect

    Tsuru, Toshinori; Shutou, Takatoshi; Nakao, Shin-Ichi; Kimura, Shoji )

    1994-05-01

    Several nanofiltration membranes [UTC-20, 60 (Toray Industries), NF-40 (Film-Tech Corporation), Desal-5, G-20 (Desalination Systems), and NTR-7450 (Nitto Electric Industrial Co.)] were applied to separate amino acids and peptides on the basis of charge interaction with the membranes since most of them contain charged functional groups. Nanofiltration membranes having a molecular weight cutoff (MWCO) below 300 (UTC-20, 60, NF-40 and Desal-5) were not suitable for separation of amino acids. On the other hand, separation of amino acids and peptides with nanofiltration membranes having a MWCO around 2000-3000 (NTR-7450 and G-20) was satisfactory based on a charge effect mechanism; charged amino acids and peptides were rejected while neutral amino acids and peptides permeated through the membranes. Separation of peptides having different isoelectric points with nanofiltration membranes was possible by adjusting the pH. 15 refs., 11 figs., 4 tabs.

  8. Crystallization of jarosite in the presence of amino acids

    NASA Astrophysics Data System (ADS)

    Crabbe, Harrison; Fernandez, Natalya; Jones, Franca

    2015-04-01

    Jarosite was formed in the presence of five amino acids at two pHs, namely 1.75 and 2.9, to determine what impact amino acids have on its formation. It was found that at the lower pH glycine was the most potent in terms of morphological and yield impacts. XRD analysis showed that incorporation of the amino acid occurs at this low pH for glycine and proline. Dynamic light scattering studies showed that glycine impacts significantly on the jarosite nucleation rate while proline and alanine do not. At the higher pH all of the amino acids had much less impact on morphology or yield. At pH 3 the solids were found to be a 3-phase system consisting of goethite, schwertmannite and jarosite. In this case, alanine appeared to stabilise the presence of schwertmannite more than the other amino acids.

  9. [Synthesis of amino acids of Bacillus subtilis IMV V-7023 in the medium with glycerophosphates].

    PubMed

    Tserkovniak, L S; Roĭ, A O; Kurdysh, I K

    2009-01-01

    It was shown that under cultivation of Bacillus subtilis IMVV-7023 in the nutrient medium with glycerophosphate biologically active substances are accumulated in the culture liquid. They influence positively the seeds growth and formation of plant germs. The bacteria synthesize amino acids in this medium, their quantitative structure differs from the type of carbon nutrition and cultivation time of the cells.

  10. Soil Bacteria Take Up D-Amino Acids, Protect Plants

    NASA Astrophysics Data System (ADS)

    Sun, H. J.; Zhang, G.

    2011-12-01

    Recently, many groups reported D-amino acid uptake by plant roots, raising the question of whether soil D-amino acids represent a source of nitrogen or a source of toxicity. The discussion needs to be placed in the context of competition with rhizosphere bacteria. To provide this context, we followed the concentrations of D- and L-enantiomers of alanine, glutamic acid, aspartic acid, and leucine after they were added to soils in the laboratory. In all cases, the uptake of L-enantiomer began immediately and proceeded rapidly until exhausted. In contrast, the uptake of D-enantiomer required induction: an initial period of inactivity followed by rapid consumption comparable in rate to L-enantiomer. The induced nature of the D activity was confirmed by the addition of rifampicin, an mRNA synthesis inhibitor. Preventing the synthesis of new enzymes abolished soil flora's ability to consume D-amino acids, but not L-amino acids. These results suggest that inducible special racemase enzymes, which can convert D-amino acids back to their native L-forms, are widespread among soil microorganisms. This finding does not rule out the possibility that some plants may out-compete microorganisms and be able to access D-amino acids. It does suggest, however, that rhizosphere bacteria can shield plants from the toxic effect of D-amino acids.

  11. Metabolic effects of intraoperative amino acid infusion in mongrel dogs.

    PubMed

    Jin, Lin; Ge, Shengjin; Wang, Hongshan; Gao, Xiaodong; Jin, Jianjun; Xue, Zhanggang

    2012-01-01

    Intraoperative amino acid infusion can attenuate the decrease in core temperature, but the metabolic effects are uncertain. Thirty-six healthy mongrel dogs undergoing ileectomy under general anesthesia were infused intraoperatively with normal saline or 18 compound amino acids at 6, 12, and 24 kJ·kg⁻¹·h⁻¹ (NS, 6-, 12-, and 24-kJ groups) and studied until 24 h after the operation. Blood glucose, plasma insulin, free fatty acids, and triglyceride concentrations were determined at 7 defined time points. Muscle aminograms, urinary urea, and 3-methylhistidine excretions were measured before and after the operation. Blood glucose and plasma insulin increased amino acid dose dependently during the operation and in the early period after the operation. Free fatty acids were significantly lower in the 12- and 24-kJ groups compared with the NS group at the end of the operation. The negative nitrogen balance was alleviated dose dependently in the amino acid groups on operation day. The urinary 3-methylhistidine decreased significantly during the first 24 h after the operation in the 24-kJ group, while it increased in the other groups with the largest increase in the NS group. Basic, branched-chain, and aromatic amino acids in the vastus lateralis muscle increased dose dependently at the end of the operation in the amino acid groups. Intraoperative amino acid infusion has the dose-dependent effects of increasing blood glucose, inhibiting fat mobilization and muscle protein breakdown.

  12. Wet, Carbonaceous Asteroids: Altering Minerals, Changing Amino Acids

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2011-04-01

    Many carbonaceous chondrites contain alteration products from water-rock interactions at low temperature and organic compounds. A fascinating fact known for decades is the presence in some of them of an assortment of organic compounds, including amino acids, sometimes called the building blocks of life. Murchison and other CM carbonaceous chondrites contain hundreds of amino acids. Early measurements indicated that the amino acids in carbonaceous chondrites had equal proportions of L- and D-structures, a situation called racemic. This was in sharp contrast to life on Earth, which heavily favors L- forms. However, beginning in 1997, John Cronin and Sandra Pizzarello (Arizona State University) found L- excesses in isovaline and several other amino acids in the Murchison carbonaceous chondrite. In 2009, Daniel Glavin and Jason Dworkin (Astrobiology Analytical Lab, Goddard Space Flight Center) reported the first independent confirmation of L-isovaline excesses in Murchison using a different analytical technique than employed by Cronin and Pizzarello. Inspired by this work, Daniel Glavin, Michael Callahan, Jason Dworkin, and Jamie Elsila (Astrobiology Analytical Lab, Goddard Space Flight Center), have done an extensive study of the abundance and symmetry of amino acids in carbonaceous chondrites that experienced a range of alteration by water in their parent asteroids. The results show that amino acids are more abundant in the less altered meteorites, implying that aqueous processing changes the mix of amino acids. They also confirmed the enrichment in L-structures of some amino acids, especially isovaline, confirming earlier work. The authors suggest that aqueously-altered planetesimals might have seeded the early Earth with nonracemic amino acids, perhaps explaining why life from microorganisms to people use only L- forms to make proteins. The initial imbalance caused by non-biologic processes in wet asteroids might have been amplified by life on Earth. Alternatively

  13. Genetics of Amino Acid Taste and Appetite123

    PubMed Central

    Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Beauchamp, Gary K

    2016-01-01

    The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. PMID:27422518

  14. Hydration of amino acids: FTIR spectra and molecular dynamics studies.

    PubMed

    Panuszko, Aneta; Adamczak, Beata; Czub, Jacek; Gojło, Emilia; Stangret, Janusz

    2015-11-01

    The hydration of selected amino acids, alanine, glycine, proline, valine, isoleucine and phenylalanine, has been studied in aqueous solutions by means of FTIR spectra of HDO isotopically diluted in H2O. The difference spectra procedure and the chemometric method have been applied to remove the contribution of bulk water and thus to separate the spectra of solute-affected HDO. To support interpretation of obtained spectral results, molecular dynamics simulations of amino acids were performed. The structural-energetic characteristic of these solute-affected water molecules shows that, on average, water affected by amino acids forms stronger and shorter H-bonds than those in pure water. Differences in the influence of amino acids on water structure have been noticed. The effect of the hydrophobic side chain of an amino acid on the solvent interactions seems to be enhanced because of the specific cooperative coupling of water strong H-bond chain, connecting the carboxyl and amino groups, with the clathrate-like H-bond network surrounding the hydrocarbon side chain. The parameter derived from the spectral data, which corresponds to the contributions of the population of weak hydrogen bonds of water molecules which have been substituted by the stronger ones in the hydration sphere of amino acids, correlated well with the amino acid hydrophobicity indexes.

  15. Profiles of amino acids and biogenic amines in the plasma of Cri-du-Chat patients.

    PubMed

    Furtado, Danielle Zildeana Sousa; de Moura Leite, Fernando Brunale Vilela; Barreto, Cleber Nunes; Faria, Bernadete; Jedlicka, Leticia Dias Lima; de Jesus Silva, Elisângela; da Silva, Heron Dominguez Torres; Bechara, Etelvino Jose Henriques; Assunção, Nilson Antonio

    2017-03-21

    Cri-du-chat syndrome (CDCS) is a rare innate disease attributed to chromosome 5p deletion characterized by a cat-like cry, craniofacial malformation, and altered behavior of affected children. Metabolomic analysis and a chemometric approach allow description of the metabolic profile of CDCS as compared to normal subjects. In the present work, UHPLC/MS was employed to analyze blood samples withdrawn from CDCS carriers (n=18) and normal parental subjects (n=18), all aged 0-34 years, aiming to set up a representative CDCS profile constructed from 33 targeted amino acids and biogenic amines. Methionine sulfoxide (MetO) was of particular concern with respect to CDCS redox balance. Increased serotonin (3-fold), methionine sulfoxide (2-fold), and Asp levels, and a little lower Orn, citrulline, Leu, Val, Ile, Asn, Gln, Trp, Thr, His, Phe, Met, and creatinine levels were found in the plasma of CDCS patients. Nitrotyrosine and Trp did not differ in normal and CDCS individuals.The accumulated metabolites may reflect, respectively, disturbances in the redox balance, deficient purine biosynthesis, and altered behavior, whereas the amino acid abatement in the latter group may affect the homeostasis of the urea cycle, citric acid cycle, branched chain amino acid synthesis, Tyr and Trp metabolism and amino acid biosynthesis. The identification of enzymatic deficiencies leading to the amino acid burden in CDCS is further required for elucidating its molecular bases and eventually propose specific or mixed amino acid supplementation to newborn patients aiming to balance their metabolism.

  16. Nickel Deficiency Disrupts Metabolism of Ureides, Amino Acids, and Organic Acids of Young Pecan Foliage[OA

    PubMed Central

    Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

    2006-01-01

    The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan. PMID:16415214

  17. Fatty acid-amino acid conjugates diversification in lepidopteran caterpillars.

    PubMed

    Yoshinaga, Naoko; Alborn, Hans T; Nakanishi, Tomoaki; Suckling, David M; Nishida, Ritsuo; Tumlinson, James H; Mori, Naoki

    2010-03-01

    Fatty acid amino acid conjugates (FACs) have been found in noctuid as well as sphingid caterpillar oral secretions; in particular, volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants. These induced volatiles, in turn, attract natural enemies of the caterpillars. In a previous study, we showed that N-linolenoyl-L-glutamine in larval Spodoptera litura plays an important role in nitrogen assimilation which might be an explanation for caterpillars synthesizing FACs despite an increased risk of attracting natural enemies. However, the presence of FACs in lepidopteran species outside these families of agricultural interest is not well known. We conducted FAC screening of 29 lepidopteran species, and found them in 19 of these species. Thus, FACs are commonly synthesized through a broad range of lepidopteran caterpillars. Since all FAC-containing species had N-linolenoyl-L-glutamine and/or N-linoleoyl-L-glutamine in common, and the evolutionarily earliest species among them had only these two FACs, these glutamine conjugates might be the evolutionarily older FACs. Furthermore, some species had glutamic acid conjugates, and some had hydroxylated FACs. Comparing the diversity of FACs with lepidopteran phylogeny indicates that glutamic acid conjugates can be synthesized by relatively primitive species, while hydroxylation of fatty acids is limited mostly to larger and more developed macrolepidopteran species.

  18. Effects of alkali or acid treatment on the isomerization of amino acids.

    PubMed

    Ohmori, Taketo; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

    2012-10-01

    The effect of alkali treatment on the isomerization of amino acids was investigated. The 100×D/(D+L) values of amino acids from peptide increased with increase in the number of constituent amino acid residues. Furthermore, the N-terminal amino acid of a dipeptide was isomerized to a greater extent than the C-terminal residue. Copyright © 2012. Published by Elsevier B.V.

  19. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    NASA Astrophysics Data System (ADS)

    Lomstein, Bente Aa.; Jørgensen, Bo B.; Schubert, Carsten J.; Niggemann, Jutta

    2006-06-01

    The spatial distribution of total hydrolysable amino acids (THAA) and amino acid enantiomers ( D- and L-forms) was investigated in sediments underlying two contrasting Chilean upwelling regions: at ˜23 °S off Antofagasta and at ˜36 °S off Concepción. The contribution of amino acids to total organic carbon (%T AAC: 7-14%) and total nitrogen (%T AAN: 23-38%) in surface sediments decreased with increasing water depth (from 126 to 1350 m) indicating that organic matter becomes increasingly decomposed in surface sediments at greater water depth. Changes in the ratio between the protein amino acid aspartate and its non-protein degradation product β-alanine confirmed this observation. Furthermore, estimates of THAA mineralization showed that sedimentary amino acid reactivity decreased with both increasing water depth as well as progressive degradation status of the organic matter that was incorporated into the sediment. Reactivity of organic matter in the sediment was also assessed using the Degradation Index (DI) developed by [Dauwe, B., Middelburg, J.J., 1998. Amino acids and hexosamines as indicators of organic matter degradation state in North Sea sediments. Limnol. Oceanogr.43, pp. 782-798.]. Off Concepción, DI was successfully applied to examine the degradation status of sedimentary organic matter at different water depths. However, unexpected results were obtained at the Antofagasta stations as DI increased with sediment depth, suggesting more degraded organic matter at the surface than deeper in the cores. The contribution of peptidoglycan amino acids to THAA was estimated from the concentrations of D-aspartate, D-glutamic acid, D-serine, and D-alanine. Peptidoglycan amino acids accounted for >18% of THAA in all investigated samples. In surface sediments peptidoglycan amino acids accounted for a progressively larger fraction of THAA at increasing water depths (up to >26%). Further, the contribution of peptidoglycan amino acids to THAA increased with

  20. Serum amino acid concentrations in patients receiving total parenteral nutrition with an amino acid plus dextrose mixture.

    PubMed

    Philcox, J C; Hartley, T F; Worthley, L I; Thomas, D W

    1984-01-01

    The results of monitoring the serum amino acid concentrations during three infusion regimens using a 5:4 mixture of 70% glucose and the synthetic L-amino acid solution, Synthamin 17 (Travasol) are reported. Twelve stabilized patients received continuous total parenteral nutrition (TPN), eight of whom were subsequently placed on a second regimen of cyclical feeding. A separate group of five patients was infused with amino acids, both with and without simultaneous glucose. The serum amino acid concentrations indicated that the supply of valine, leucine, isoleucine, lysine, and histidine, and the synthesis of taurine from the infused methionine was suboptimal, particularly if the period of TPN was prolonged. The synthesis of tyrosine from phenylalanine appeared to be inversely proportional to the infusion rate of the TPN mixture, in particular the glucose component, resulting in depressed tyrosine and increased phenylalanine concentrations in serum during continuous iv nutrition. Cyclical infusions, on the other hand, permitted the tyrosine and phenylalanine concentrations to return to normal during the noninfusion stage of the cycle. Amino acid measurements enabled us to design an amino acids additive mixture which normalized the serum concentrations in three long-term home parenteral nutrition patients. As a result of these investigations serum amino acid measurements are used routinely to monitor the efficacy of TPN and accommodate any specific amino acid requirements of individual patients.

  1. Quantitative analysis of 17 amino acids in tobacco leaves using an amino acid analyzer and chemometric resolution.

    PubMed

    Zeng, Yihang; Cai, Wensheng; Shao, Xueguang

    2015-06-01

    A method was developed for quantifying 17 amino acids in tobacco leaves by using an A300 amino acid analyzer and chemometric resolution. In the method, amino acids were eluted by the buffer solution on an ion-exchange column. After reacting with ninhydrin, the derivatives of amino acids were detected by ultraviolet detection. Most amino acids are separated by the elution program. However, five peaks of the derivatives are still overlapping. A non-negative immune algorithm was employed to extract the profiles of the derivatives from the overlapping signals, and then peak areas were adopted for quantitative analysis of the amino acids. The method was validated by the determination of amino acids in tobacco leaves. The relative standard deviations (n = 5) are all less than 2.54% and the recoveries of the spiked samples are in a range of 94.62-108.21%. The feasibility of the method was proved by analyzing the 17 amino acids in 30 tobacco leaf samples.

  2. D-Amino acids in the brain and mutant rodents lacking D-amino-acid oxidase activity.

    PubMed

    Yamanaka, Masahiro; Miyoshi, Yurika; Ohide, Hiroko; Hamase, Kenji; Konno, Ryuichi

    2012-11-01

    D-Amino acids are stereoisomers of L-amino acids. They are often called unnatural amino acids, but several D-amino acids have been found in mammalian brains. Among them, D-serine is abundant in the forebrain and functions as a co-agonist of NMDA receptors to enhance neurotransmission. D-Amino-acid oxidase (DAO), which degrades neutral and basic D-amino acids, is mainly present in the hindbrain. DAO catabolizes D-serine and, therefore, modulates neurotransmission. In the brains of mutant mice and rats lacking DAO activity, the amounts of D-serine and other D-amino acids are markedly increased. Mutant mice manifested behavioral changes characteristic of altered NMDA receptor activity, likely due to increased levels of D-serine. D-Serine and DAO have been demonstrated to play important roles in cerebellar development and synaptic plasticity. They have also implicated in amyotrophic lateral sclerosis and pain response. There have also been several lines of evidence correlating DAO with schizophrenia. Taken together, the experiments indicate that D-amino acids and DAO have pivotal functions in the central nervous system.

  3. Single Amino Acid Repeats in the Proteome World: Structural, Functional, and Evolutionary Insights

    PubMed Central

    Kumar, Amitha Sampath; Sowpati, Divya Tej; Mishra, Rakesh K.

    2016-01-01

    Microsatellites or simple sequence repeats (SSR) are abundant, highly diverse stretches of short DNA repeats present in all genomes. Tandem mono/tri/hexanucleotide repeats in the coding regions contribute to single amino acids repeats (SAARs) in the proteome. While SSRs in the coding region always result in amino acid repeats, a majority of SAARs arise due to a combination of various codons representing the same amino acid and not as a consequence of SSR events. Certain amino acids are abundant in repeat regions indicating a positive selection pressure behind the accumulation of SAARs. By analysing 22 proteomes including the human proteome, we explored the functional and structural relationship of amino acid repeats in an evolutionary context. Only ~15% of repeats are present in any known functional domain, while ~74% of repeats are present in the disordered regions, suggesting that SAARs add to the functionality of proteins by providing flexibility, stability and act as linker elements between domains. Comparison of SAAR containing proteins across species reveals that while shorter repeats are conserved among orthologs, proteins with longer repeats, >15 amino acids, are unique to the respective organism. Lysine repeats are well conserved among orthologs with respect to their length and number of occurrences in a protein. Other amino acids such as glutamic acid, proline, serine and alanine repeats are generally conserved among the orthologs with varying repeat lengths. These findings suggest that SAARs have accumulated in the proteome under positive selection pressure and that they provide flexibility for optimal folding of functional/structural domains of proteins. The insights gained from our observations can help in effective designing and engineering of proteins with novel features. PMID:27893794

  4. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    NASA Technical Reports Server (NTRS)

    Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

    2007-01-01

    Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

  5. Algal swimming velocities signal fatty acid accumulation.

    PubMed

    Hansen, Travis J; Hondzo, Miki; Mashek, Mara T; Mashek, Douglas G; Lefebvre, Paul A

    2013-01-01

    The use of microalgae for biofuel production will be beneficial to society if we can produce biofuels at large scales with minimal mechanical energy input in the production process. Understanding micro-algal physiological responses under variable environmental conditions in bioreactors is essential for the optimization of biofuel production. We demonstrate that measuring micro-algal swimming speed provides information on culture health and total fatty acid accumulation. Three strains of Chlamydomonas reinhardtii were grown heterotrophically on acetate and subjected to various levels of nitrogen starvation. Other nutrient levels were explored to determine their effect on micro-algal kinetics. Swimming velocities were measured with two-dimensional micro-particle tracking velocimetry. The results show an inverse linear relationship between normalized total fatty acid mass versus swimming speed of micro-algal cells. Analysis of RNA sequencing data confirms these results by demonstrating that the biological processes of cell motion and the generation of energy precursors are significantly down-regulated. Experiments demonstrate that changes in nutrient concentration in the surrounding media also affect swimming speed. The findings have the potential for the in situ and indirect assessment of lipid content by measuring micro-algal swimming kinetics.

  6. Graphdiyne as a promising material for detecting amino acids

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Gao, Pengfei; Guo, Lei; Zhang, Shengli

    2015-11-01

    The adsorption of glycine, glutamic acid, histidine and phenylalanine on single-layer graphdiyne/ graphene is investigated by ab initio calculations. The results show that for each amino acid molecule, the adsorption energy on graphdiyne is larger than the adsorption energy on graphene and dispersion interactions predominate in the adsorption. Molecular dynamics simulations reveal that at room temperature the amino acid molecules keep migrating and rotating on graphdiyne surface and induce fluctuation in graphdiyne bandgap. Additionally, the photon absorption spectra of graphdiyne-amino-acid systems are investigated. We uncover that the presence of amino acid molecules makes the photon absorption peaks of graphdiyne significantly depressed and shifted. Finally, quantum electronic transport properties of graphdiyne-amino-acid systems are compared with the transport properties of pure graphdiyne. We reveal that the amino acid molecules induce distinct changes in the electronic conductivity of graphdiyne. The results in this paper reveal that graphdiyne is a promising two-dimensional material for sensitively detecting amino acids and may potentially be used in biosensors.

  7. Regulation of myocardial amino acid balance in the conscious dog.

    PubMed Central

    Schwartz, R G; Barrett, E J; Francis, C K; Jacob, R; Zaret, B L

    1985-01-01

    The effects in vivo of physiologic increases in insulin and amino acids on myocardial amino acid balance were evaluated in conscious dogs. Arterial and coronary sinus concentrations of amino acids and coronary blood flow were measured during a 30-min basal and a 100-min experimental period employing three protocols: euglycemic insulin clamp (plasma insulin equaled 70 +/- 11 microU/ml, n = 6); euglycemic insulin clamp during amino acid infusion (plasma insulin equaled 89 +/- 12 microU/ml, n = 6); and suppression of insulin with somatostatin during amino acid infusion (plasma insulin equaled 15 +/- 4 microU/ml, n = 6). Basally, only leucine and isoleucine were removed significantly by myocardium (net branched chain amino acid [BCAA] uptake equaled 0.5 +/- 0.2 mumol/min), while glycine, alanine, and glutamine were released. Glutamine demonstrated the highest net myocardial production (1.6 +/- 0.2 mumol/min). No net exchange was seen for valine, phenylalanine, tyrosine, cysteine, methionine, glutamate, asparagine, serine, threonine, taurine, and aspartate. In group I, hyperinsulinemia caused a decline of all plasma amino acids except alanine; alanine balance switched from release to an uptake of 0.6 +/- 0.4 mumol/min (P less than 0.05), while the myocardial balance of other amino acids was unchanged. In group II, amino acid concentrations rose, and were accompanied by a marked rise in myocardial BCAA uptake (0.4 +/- 0.1-2.6 +/- 0.3 mumol/min, P less than 0.001). Uptake of alanine was again stimulated (0.9 +/- 0.3 mumol/min, P less than 0.01), while glutamine production was unchanged (1.3 +/- 0.4 vs. 1.6 +/- 0.3 mumol/min). In group III, there was a 4-5-fold increase in the plasma concentration of the infused amino acids, accompanied by marked stimulation in uptake of only BCAA (6.8 +/- 0.7 mumol/min). Myocardial glutamine production was unchanged (1.9 +/- 0.4-1.3 +/- 0.7 mumol/min). Within the three experimental groups there were highly significant linear correlations

  8. Amino acid synthesis in a supercritical carbon dioxide - water system.

    PubMed

    Fujioka, Kouki; Futamura, Yasuhiro; Shiohara, Tomoo; Hoshino, Akiyoshi; Kanaya, Fumihide; Manome, Yoshinobu; Yamamoto, Kenji

    2009-06-15

    Mars is a CO(2)-abundant planet, whereas early Earth is thought to be also CO(2)-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO(2)/liquid H(2)O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life's origin.

  9. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    PubMed Central

    Fujioka, Kouki; Futamura, Yasuhiro; Shiohara, Tomoo; Hoshino, Akiyoshi; Kanaya, Fumihide; Manome, Yoshinobu; Yamamoto, Kenji

    2009-01-01

    Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin. PMID:19582225

  10. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    PubMed Central

    Barazzouk, Saïd; Daneault, Claude

    2012-01-01

    In this work, oxidized nanocellulose (ONC) was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl) carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides) were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectroscopic techniques.

  11. Transaminases for the synthesis of enantiopure beta-amino acids

    PubMed Central

    2012-01-01

    Optically pure β-amino acids constitute interesting building blocks for peptidomimetics and a great variety of pharmaceutically important compounds. Their efficient synthesis still poses a major challenge. Transaminases (also known as aminotransferases) possess a great potential for the synthesis of optically pure β-amino acids. These pyridoxal 5'-dependent enzymes catalyze the transfer of an amino group from a donor substrate to an acceptor, thus enabling the synthesis of a wide variety of chiral amines and amino acids. Transaminases can be applied either for the kinetic resolution of racemic compounds or the asymmetric synthesis starting from a prochiral substrate. This review gives an overview over microbial transaminases with activity towards β-amino acids and their substrate spectra. It also outlines current strategies for the screening of new biocatalysts. Particular emphasis is placed on activity assays which are applicable to high-throughput screening. PMID:22293122

  12. Amino acid sequence of toxin III from Anemonia sulcata.

    PubMed

    Bĕress, L; Wunderer, G; Wachter, E

    1977-08-01

    Toxin III, the smallest toxin component of the poison of the sea anemone Anemonia sulcata, is a polypeptide with 27 amino acids. Its structure is stabilized by three disulfide bridges. The amino acid sequence was determined by solid-phase Edman degradation of the aminoethylated derivative. The peptide was coupled to the carrier, porous glass, by thiourea bridges between the alpha-amino group of arginine-1 and the epsilon-amino group of lysine-26 and the isothiocyanate groups of the carrier. Another fraction of the polypeptide was bound by an acid-amide condensation of the C-terminal valine-27 with the aminopropyl group of the carrier. The sequence of toxin III has no regions homologous to the 47-residue toxin II. Comparison with the known partial sequence of toxin I, which contains 46 amino acids (Wunderer, G. & Eulitz, M., in preparation) also fails to reveal homologies.

  13. Prolonged maternal amino acid infusion in late-gestation pregnant sheep increases fetal amino acid oxidation.

    PubMed

    Rozance, Paul J; Crispo, Michelle M; Barry, James S; O'Meara, Meghan C; Frost, Mackenzie S; Hansen, Kent C; Hay, William W; Brown, Laura D

    2009-09-01

    Protein supplementation during human pregnancy does not improve fetal growth and may increase small-for-gestational-age birth rates and mortality. To define possible mechanisms, sheep with twin pregnancies were infused with amino acids (AA group, n = 7) or saline (C group, n = 4) for 4 days during late gestation. In the AA group, fetal plasma leucine, isoleucine, valine, and lysine concentrations were increased (P < 0.05), and threonine was decreased (P < 0.05). In the AA group, fetal arterial pH (7.365 +/- 0.007 day 0 vs. 7.336 +/- 0.012 day 4, P < 0.005), hemoglobin-oxygen saturation (46.2 +/- 2.6 vs. 37.8 +/- 3.6%, P < 0.005), and total oxygen content (3.17 +/- 0.17 vs. 2.49 +/- 0.20 mmol/l, P < 0.0001) were decreased on day 4 compared with day 0. Fetal leucine disposal did not change (9.22 +/- 0.73 vs. 8.09 +/- 0.63 micromol x min(-1) x kg(-1), AA vs. C), but the rate of leucine oxidation increased 43% in the AA group (2.63 +/- 0.16 vs. 1.84 +/- 0.24 micromol x min(-1) x kg(-1), P < 0.05). Fetal oxygen utilization tended to be increased in the AA group (327 +/- 23 vs. 250 +/- 29 micromol x min(-1) x kg(-1), P = 0.06). Rates of leucine incorporation into fetal protein (5.19 +/- 0.97 vs. 5.47 +/- 0.89 micromol x min(-1) x kg(-1), AA vs. C), release from protein breakdown (4.20 +/- 0.95 vs. 4.62 +/- 0.74 micromol x min(-1) x kg(-1)), and protein accretion (1.00 +/- 0.30 vs. 0.85 +/- 0.25 micromol x min(-1) x kg(-1)) did not change. Consistent with these data, there was no change in the fetal skeletal muscle ubiquitin ligases MaFBx1 or MuRF1 or in the protein synthesis regulators 4E-BP1, eEF2, eIF2alpha, and p70(S6K). Decreased concentrations of certain essential amino acids, increased amino acid oxidation, fetal acidosis, and fetal hypoxia are possible mechanisms to explain fetal toxicity during maternal amino acid supplementation.

  14. Amino acid profiles of lactic acid bacteria, isolated from kefir grains and kefir starter made from them.

    PubMed

    Simova, Emilina; Simov, Zhelyasko; Beshkova, Dora; Frengova, Ginka; Dimitrov, Zhechko; Spasov, Zdravko

    2006-03-15

    - and 60-fold increase in the concentration of lactobacilli and cocci in the mixed culture compared to individual cultures; and accumulated free amino acids in the final kefir with higher total concentrations (56.88 mg (100 g)(-1)) and an individual concentration of essential amino acids (1.5 times) greater than that of yogurt.

  15. The indicator amino acid oxidation method identified limiting amino acids in two parenteral nutrition solutions in neonatal piglets.

    PubMed

    Brunton, Janet A; Shoveller, Anna K; Pencharz, Paul B; Ball, Ronald O

    2007-05-01

    Recent studies using the indicator amino acid oxidation (IAAO) technique in TPN-fed piglets and infants have been instrumental in defining parenteral amino acid requirements. None of the commercial products in use are ideal when assessed against these new data. Our objectives were to determine whether the oxidation of an indicator amino acid would decline with the addition of amino acids that were limiting in the diets of TPN-fed piglets, and to use this technique to identify limiting amino acids in a new amino acid profile. Piglets (n = 26) were randomized to receive TPN with amino acids provided by Vaminolact (VM) or by a new profile (NP). After 5 d of TPN administration, lysine oxidation was measured using a constant infusion of L- [1-(14)C]-lysine. Immediately following the first IAAO study, the piglets were further randomized within diet group to receive either 1) supplemental aromatic amino acids (AAA), 2) sulfur amino acids (SAA) or 3) both (AAA+SAA) (n = 4-5 per treatment group). A second IAAO study was carried out 18 h later. In the first IAAO study, lysine oxidation was high for both groups (18 vs. 21% for VM and NP, respectively, P = 0.055). The addition of AAA to VM induced a 30% decline in lysine oxidation compared with baseline (P < 0.01). Similarly, SAA added to NP lowered lysine oxidation by approximately 30% (P < 0.01). The application of the IAAO technique facilitates rapid evaluation of the amino acids that are limiting to protein synthesis in parenteral solutions.

  16. The expansion of amino-acid repeats is not associated to adaptive evolution in mammalian genes

    PubMed Central

    2009-01-01

    Background The expansion of amino acid repeats is determined by a high mutation rate and can be increased or limited by selection. It has been suggested that recent expansions could be associated with the potential of adaptation to new environments. In this work, we quantify the strength of this association, as well as the contribution of potential confounding factors. Results Mammalian positively selected genes have accumulated more recent amino acid repeats than other mammalian genes. However, we found little support for an accelerated evolutionary rate as the main driver for the expansion of amino acid repeats. The most significant predictors of amino acid repeats are gene function and GC content. There is no correlation with expression level. Conclusions Our analyses show that amino acid repeat expansions are causally independent from protein adaptive evolution in mammalian genomes. Relaxed purifying selection or positive selection do not associate with more or more recent amino acid repeats. Their occurrence is slightly favoured by the sequence context but mainly determined by the molecular function of the gene. PMID:20021652

  17. Amino Acid Homeostasis and Chronological Longevity in Saccharomyces cerevisiae

    PubMed Central

    Aris, John P.; Fishwick, Laura K.; Marraffini, Michelle L.; Seo, Arnold Y.; Leeuwenburgh, Christiaan; Dunn, William A.

    2015-01-01

    Understanding how non-dividing cells remain viable over long periods of time, which may be decades in humans, is of central importance in understanding mechanisms of aging and longevity. The long-term viability of non-dividing cells, known as chronological longevity, relies on cellular processes that degrade old components and replace them with new ones. Key among these processes is amino acid homeostasis. Amino acid homeostasis requires three principal functions: amino acid uptake, de novo synthesis, and recycling. Autophagy plays a key role in recycling amino acids and other metabolic building blocks, while at the same time removing damaged cellular components such as mitochondria and other organelles. Regulation of amino acid homeostasis and autophagy is accomplished by a complex web of pathways that interact because of the functional overlap at the level of recycling. It is becoming increasingly clear that amino acid homeostasis and autophagy play important roles in chronological longevity in yeast and higher organisms. Our goal in this chapter is to focus on mechanisms and pathways that link amino acid homeostasis, autophagy, and chronological longevity in yeast, and explore their relevance to aging and longevity in higher eukaryotes. PMID:22094422

  18. Differential diagnosis of (inherited) amino acid metabolism or transport disorders.

    PubMed

    Blom, W; Huijmans, J G

    1992-02-01

    Disorders of amino acid metabolism or transport are most clearly expressed in urine. Nevertheless the interpretation of abnormalities in urinary amino acid excretion remains difficult. An increase or decrease of almost every amino acid in urine can be due to various etiology. To differentiate between primary and secondary aminoacido-pathies systematic laboratory investigation is necessary. Early diagnosis of disorders of amino acid metabolism or transport is very important, because most of them can be treated, leading to the prevention of (further) clinical abnormalities. In those disorders, which cannot be treated, early diagnosis in an index-patient may prevent the birth of other siblings by means of genetic counseling and prenatal diagnosis.Primary aminoacidopathies can be due to genetically determined transport disorders and enzyme deficiencies in amino acid metabolism or degradation. Secondary aminoacidopathies are the result of abnormal or deficient nutrition, intestinal dysfunction, organ pathology or other metabolic diseases like organic acidurias.A survey of amino acid metabolism and transport abnormalities will be given, illustrated with metabolic pathways and characteristic abnormal amino acid chromatograms.

  19. New Functions and Potential Applications of Amino Acids.

    PubMed

    Uneyama, Hisayuki; Kobayashi, Hisamine; Tonouchi, Naoto

    Currently, several types of amino acids are being produced and used worldwide. Nevertheless, several new functions of amino acids have been recently discovered that could result in other applications. For example, oral stimulation by glutamate triggers the cephalic phase response to prepare for food digestion. Further, the stomach and intestines have specific glutamate-recognizing systems in their epithelial mucosa. Regarding clinical applications, addition of monosodium glutamate to the medicinal diet has been shown to markedly enhance gastric secretion in a vagus-dependent manner. Branched-chain amino acids (BCAAs) are the major components of muscles, and ingestion of BCAAs has been found to be effective for decreasing muscle pain. BCAAs are expected to be a solution for the serious issue of aging. Further, ingestion of specific amino acids could be beneficial. Glycine can be ingested for good night's sleep: glycine ingestion before bedtime significantly improved subjective sleep quality. Ingestion of alanine and glutamine effectively accelerates alcohol metabolism, and ingestion of cystine and theanine effectively prevents colds. Finally, amino acids could be used in a novel clinical diagnostic method: the balance of amino acids in the blood could be an indicator of the risk of diseases such as cancer. These newly discovered functions of amino acids are expected to contribute to the resolution of various issues.

  20. Cyanobacteria as efficient producers of mycosporine-like amino acids.

    PubMed

    Jain, Shikha; Prajapat, Ganshyam; Abrar, Mustari; Ledwani, Lalita; Singh, Anoop; Agrawal, Akhil

    2017-09-01

    Mycosporine-like amino acids are the most common group of transparent ultraviolet radiation absorbing intracellular secondary metabolites. These molecules absorb light in the range of ultraviolet-A and -B with a maximum absorbance between 310 and 362 nm. Cyanobacteria might have faced the most deleterious ultraviolet radiation, which leads to an evolution of ultraviolet protecting mycosporine-like amino acids for efficient selection in the environment. In the last 30 years, scientists have investigated various cyanobacteria for novel mycosporine-like amino acids, applying different induction techniques. This review organizes all the cyanobacterial groups that produce various mycosporine-like amino acids. We found out that cyanobacteria belonging to orders Synechococcales, Chroococcales, Oscillatoriales, and Nostocales are frequently studied for the presence of mycosporine-like amino acids, while orders Gloeobacterales, Spirulinales, Pleurocapsales, and Chroococcidiopsidales are still need to be investigated. Nostoc and Anabae