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Sample records for amino acid uptake

  1. Metabolic regulation of amino acid uptake in marine waters

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  2. Cystine and dibasic amino acid uptake by opossum kidney cells

    International Nuclear Information System (INIS)

    The characteristics of the uptake of L-cystine by the continuous opossum kidney cell line, OK, were examined. Uptake of cystine is rapid and, in contrast to other continuous cultured cell lines, these cells retain the cystine/dibasic amino acid transport system which is found in vivo and in freshly isolated kidney tissue. Confluent monolayers of cells also fail to show the presence of the cystine/glutamate transport system present in LLC-PK1 cells, fibroblasts, and cultured hepatocytes. Uptake of cystine occurs via a high-affinity saturable process which is independent of medium sodium concentration. The predominant site of cystine transport is across the apical cell membrane. The intracellular concentration of GSH far exceeds that of cystine with a ratio greater than 100:1 for GSH:cysteine. Incubation of cells for 5 minutes with a physiological level of labelled cystine resulted in the labelling of 66% and 5% of the total intracellular cysteine and glutathione, respectively. The ability of these cells to reflect the shared cystine/dibasic amino acid transport system makes them a suitable model for investigation of the cystine carrier which is altered in human cystinuria

  3. Cystine and dibasic amino acid uptake by opossum kidney cells

    Energy Technology Data Exchange (ETDEWEB)

    States, B.; Segal, S. (Children' s Hospital of Philadelphia, PA (USA))

    1990-06-01

    The characteristics of the uptake of L-cystine by the continuous opossum kidney cell line, OK, were examined. Uptake of cystine is rapid and, in contrast to other continuous cultured cell lines, these cells retain the cystine/dibasic amino acid transport system which is found in vivo and in freshly isolated kidney tissue. Confluent monolayers of cells also fail to show the presence of the cystine/glutamate transport system present in LLC-PK1 cells, fibroblasts, and cultured hepatocytes. Uptake of cystine occurs via a high-affinity saturable process which is independent of medium sodium concentration. The predominant site of cystine transport is across the apical cell membrane. The intracellular concentration of GSH far exceeds that of cystine with a ratio greater than 100:1 for GSH:cysteine. Incubation of cells for 5 minutes with a physiological level of labelled cystine resulted in the labelling of 66% and 5% of the total intracellular cysteine and glutathione, respectively. The ability of these cells to reflect the shared cystine/dibasic amino acid transport system makes them a suitable model for investigation of the cystine carrier which is altered in human cystinuria.

  4. Uptake of Branched-Chain Amino Acids by Streptococcus thermophilus

    OpenAIRE

    Akpemado, K. M.; Bracquart, P. A.

    1983-01-01

    The transport of branched-chain amino acids in Streptococcus thermophilus was energy dependent. The metabolic inhibitors of glycolysis and ATPase enzymes were active, but the proton-conducting uncouplers were not. Transport was optimal at temperatures of between 30 and 45°C and at pH 7.0 for the three amino acids leucine, valine, and isoleucine; a second peak existed at pH 5.0 with valine and isoleucine. By competition and kinetics studies, the branched-chain amino acids were found to share a...

  5. Uptake and metabolism of dissolved amino acids by larvae and embryos of three gastropod species

    International Nuclear Information System (INIS)

    Dissolved organic matter is a potential nutritional resource for soft-bodied marine invertebrates. Experiments were done with developmental stages of three gastropod species to examine uptake kinetics and metabolism of dissolved amino acids. Free-swimming larvae of Crepidula fornicata and Thais-haemastoma were fed before experiments or starved for 48 hours before experiments to see whether nutritional state affected uptake of 14C-glycine of 14C-alanine. Time course of amino acid uptake was linear from 0-100 minutes for fed and starved larvae of both species. Uptake rates of starved T. haemastoma larvae were similar to or greater than rates for fed larvae, while uptake rates of starved C. fornicata larvae are similar to or less than rates for fed larvae. Starvation may enhance uptake by T. haemastoma larvae. 14CO2 was detected 10 minutes after larval exposure to labeled amino acids began, indicating rapid catabolism of amino acids. Label was found in protein extracted from larvae, indicating that absorbed glycine and alanine can be used for protein synthesis. A greater percent of glycine and alanine was converted to CO2 by starved larvae of both species. Encapsulated embryos of Nucella lapillus were used to study uptake and metabolism of amino acids because encapsulated embryos are in a bacteria-free environment. Uptake by embryos was linear from 10-90 minutes. Because capsules were bacteria-free embryos were the agents responsible for uptake and metabolism of labeled amino acids

  6. The effect of fluoride on the cellular uptake and pool of amino acids

    International Nuclear Information System (INIS)

    Fluoride decreased the initial uptake of 2-aminoisobutyric acid (AIB) in LS cells only in high (supralethal) concentrations and after several hours of exposure. The steady state level of AIB seemed somewhat more sensitive as it was halved after 23 hours exposure to 6mM-NaF. The cellular levels of some natural amino acids were also reduced by fluoride. However, cells resistant to fluoride showed equally lowered levels of amino acids, indicating that the observed effect of fluoride on cellular amino acid levels may be of little importance. (author)

  7. Amino acid uptake in the skeletal muscle measured using [11C]methylaminoisobutyrate (MEAIB) and PET

    International Nuclear Information System (INIS)

    An amino acid analogue, [11C]MeAIB, recently introduced for oncological positron emission tomography (PET) studies, is a highly selective substrate for insulin-sensitive amino acid transport system A. The aim of this study was to study the uptake kinetics of [11C]MeAIB in skeletal muscle in the fasting state and during insulin stimulation. Two dynamic PET studies were carried out in 11 healthy subjects, once in the fasting state and once during euglycaemic hyperinsulinaemia (serum insulin 67±12 mU l-1). Graphical analysis was used to calculate the fractional [11C]MeAIB uptake rate (Ki). Amino acid uptake was estimated by multiplying Ki by the serum amino acid concentration. After tracer injection, rapid uptake in muscle tissue was detected both in the fasting state and during insulin stimulation and femoral muscles were clearly visualised in both studies. In the graphical analysis, the volume of distribution of [11C]MeAIB plotted against normalised plasma time yielded a linear curve (the slope of which = Ki). The fractional [11C]MeAIB uptake rate (Ki) in the femoral muscle regions increased from 0.0070±0.0018 min-1 (mean±SD) in the fasting state to 0.0079±0.0020 min-1 (P-1 (P-1 (P=0.0001) during hyperinsulinaemia. The calculated skeletal muscle total amino acid uptake and the uptake of the six amino acids typically using system A were similar in the fasting state and during insulin clamp (17.1±3.2 vs 17.7±3.7 μmol kg-1 min-1, NS, and 5.0±1.3 vs 5.0±1.4 μmol kg-1 min-1, NS, respectively). The uptake rates correlated with perfusion both in the fasting state and during hyperinsulinaemia (P11C]MeAIB PET appears to be a feasible method for measurement of amino acid uptake in human skeletal muscle. As a tracer that is not metabolised in the tissues, [11C]MeAIB provides simple modelling and robust data analysis and thus provides a means to investigate amino acid uptake into muscle tissue in various disease conditions known to affect protein metabolism. (orig.)

  8. Uptake of neutral alpha- and beta-amino acids by human proximal tubular cells

    DEFF Research Database (Denmark)

    Jessen, H; Røigaard, H; Jacobsen, Christian

    1996-01-01

    relatively low. Nor did L-arginine and L-aspartic acid affect the uptake of beta-alanine into AHKE cells. Comparison with the results obtained for normal (NHKE) and immortalized (IHKE) embryonic cells suggested an unaltered expression of the types of transport carriers for neutral alpha- and beta-amino acids...

  9. Amino acids

    Science.gov (United States)

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  10. Effect of exercise and obesity on skeletal muscle amino acid uptake

    International Nuclear Information System (INIS)

    To determine if amino acid uptake by muscle of the obese Zucker rat is impaired, epitrochlearis (EPI) and soleus strip (SOL) muscles from 32 pairs of female lean (Fa/-) and obese (fa/fa) Zucker rats were incubated using [14C]α-aminoisobutyric acid (AIB). Because contractile activity also influences amino acid uptake, the effect of acute endurance exercise on amino acid uptake by skeletal muscle from lean and obese rats was also studied. Muscle wet and dry weights were similar in lean and obese rats. However, both muscle protein content and concentration from obese rats were significantly reduced. In preliminary studies, pinning EPI at resting length during incubation significantly increased AIB uptake and reduced muscle water accumulation. AIB uptake was similar in stripped and intact SOL. Lean and obese rats were studied at rest or following a 1 hr treadmill run at 8% grade Muscles were pinned, and preincubated for 30 min at 37 degree C in Krebs Ringer bicarbonate buffer (KRB) containing 5mM glucose under 95:5 O2/CO2, followed by 30, 60, 120, or 180 min of incubation in KRB with 0.5 mM AIB, [14C]-AIB to measure amino acid, and [3H]-inulin to determine extracellular water

  11. Proton-dependent glutamine uptake by aphid bacteriocyte amino acid transporter ApGLNT1.

    Science.gov (United States)

    Price, Daniel R G; Wilson, Alex C C; Luetje, Charles W

    2015-10-01

    Aphids house large populations of the gammaproteobacterial symbiont Buchnera aphidicola in specialized bacteriocyte cells. The combined biosynthetic capability of the holobiont (Acyrthosiphon pisum and Buchnera) is sufficient for biosynthesis of all twenty protein coding amino acids, including amino acids that animals alone cannot synthesize; and that are present at low concentrations in A. pisum's plant phloem sap diet. Collaborative holobiont amino acid biosynthesis depends on glutamine import into bacteriocytes, which serves as a nitrogen-rich amino donor for biosynthesis of other amino acids. Recently, we characterized A. pisum glutamine transporter 1 (ApGLNT1), a member of the amino acid/auxin permease family, as the dominant bacteriocyte plasma membrane glutamine transporter. Here we show ApGLNT1 to be structurally and functionally related to mammalian proton-dependent amino acid transporters (PATs 1-4). Using functional expression in Xenopus laevis oocytes, combined with two-electrode voltage clamp electrophysiology we demonstrate that ApGLNT1 is electrogenic and that glutamine induces large inward currents. ApGLNT1 glutamine induced currents are dependent on external glutamine concentration, proton (H+) gradient across the membrane, and membrane potential. Based on these transport properties, ApGLNT1-mediated glutamine uptake into A. pisum bacteriocytes can be regulated by changes in either proton gradients across the plasma membrane or membrane potential. PMID:26028424

  12. Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

    Directory of Open Access Journals (Sweden)

    E. Gioseffi

    2012-04-01

    Full Text Available Soil-borne amino acids may constitute a source of nitrogen (N for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly and glutamine (Gln by wheat roots and their interactions with nitrate (NO3 and ammonium (NH4+ during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake, thereby resulting in similar total N uptake rates. Amino acids were enriched with double-labelled 15N and 13C, while NO3 and NH4+ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO3 and NH4+ did not differ from each other and were generally about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50% of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO3 did not affect glycine uptake, while the presence of glycine down-regulated NO3 uptake. The ratio between 13C and 15N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction

  13. Reducing Renal Uptake of {sup 177}Lu Labeled CCK Derivative using Basic Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soyoung; Lim, Jaecheong; Joh, Eunha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Radiolabeled peptides have been designed to target the relative receptors overespressed in tumor cells, such as integrin αvβ3, gastrin-releasing peptide receptor (GRPR), melanocortin-1 receptor (MC1-R), glucagon-like peptide-a receptor (GLP-1R), and cholecystokinin (CCK) receptor. Most of these peptides are eliminated from the body via the kidney and are partly reabsorbed in the proximal tubular cells. However, the high renal uptake of the radiolabeled peptides may lead to renal toxicity. In this study we investigated various amino acid solutions to reduce the renal uptake of {sup 177}Lu-DOTA-CCK derivative. Renal uptake of {sup 177}Lu-DOTA-CCK derivative is effectively reduced by the administration of positively charged amino acids. The administration of 12 mg of L-lysine was as effective in reducing the renal uptake as 6 mg of lysine and 6 mg of arginine combinations. Further studies will be performed to identify the most potent inhibitor of renal reuptake of radiolabeled peptides and minimize the chance of unwanted side effects.

  14. Reducing Renal Uptake of 177Lu Labeled CCK Derivative using Basic Amino Acids

    International Nuclear Information System (INIS)

    Radiolabeled peptides have been designed to target the relative receptors overespressed in tumor cells, such as integrin αvβ3, gastrin-releasing peptide receptor (GRPR), melanocortin-1 receptor (MC1-R), glucagon-like peptide-a receptor (GLP-1R), and cholecystokinin (CCK) receptor. Most of these peptides are eliminated from the body via the kidney and are partly reabsorbed in the proximal tubular cells. However, the high renal uptake of the radiolabeled peptides may lead to renal toxicity. In this study we investigated various amino acid solutions to reduce the renal uptake of 177Lu-DOTA-CCK derivative. Renal uptake of 177Lu-DOTA-CCK derivative is effectively reduced by the administration of positively charged amino acids. The administration of 12 mg of L-lysine was as effective in reducing the renal uptake as 6 mg of lysine and 6 mg of arginine combinations. Further studies will be performed to identify the most potent inhibitor of renal reuptake of radiolabeled peptides and minimize the chance of unwanted side effects

  15. Methyl mercury uptake across bovine brain capillary endothelial cells in vitro: The role of amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Aschner, M.; Clarkson, T.W. (Environmental Health Sciences Center, University of Rochester, School of Medicine and Dentistry, Rochester, New York (USA))

    1989-01-01

    Previous studies in the rat in vivo have demonstrated that co-injection of methyl mercury (MeHg) with L-cysteine into the common carotid artery enhances brain Hg levels folowing a single capillary pass through the CNS vasculature. In order to elucidate the relationship between MeHg transport and the neutral amino acid transport carrier system, regulatory aspects of MeHg transport across the bovine blood-brain barrier were investigated in isolated brain microvessel preparations. Following 1 hour co-incubations of /sup 203/Hg-MeHgCl with 0.1 mM L-cysteine at 37 deg. C, /sup 203/Hg uptake by suspended microvessels was significantly increased (P<0.05) compared with controls. This enhanced capillary uptake of /sup 203/Hg was abolished by co-incubations of microvessels with 0.1 mM L-cysteine-L-methionine, or 0.1 mM L-cysteine plus AT-125 (alpha S, 5S-alpha-amino-3-chloro-4,5-dihydro-5-isoxazolacetic acid), an irreversible inhibitor of gamma-glutamyl-transpeptidase. One hr co-incubations of bovine capilaries with /sup 203/Hg-MeHgCl and 0.1 mM D-cysteine at 37 deg. C or 0.1 mM L-cysteine at 0 deg. did not increase rat of /sup 203/Hg uptake compared with controls. These results indicate that L-cysteine enhances the rate of capillary MeHg uptake. The accumulation of /sup 203/Hg in the bovine microvessels appears to be a carrier-mediated process. It is inhibited by L-methionin, a competitive substrate for neutral amino acid transport, and by AT-125. Capillary uptake of /sup 203/Hg is stereospecific to the L-enantiomorph of cystine, suggesting selective uptake of MeHg across the blood-brain barrier. The data emphasize the relationship between the L-enantiomorph neutral amino acid carrier system and MeHg transport across the capillaries. (author).

  16. Glycinergic-Fipronil Uptake Is Mediated by an Amino Acid Carrier System and Induces the Expression of Amino Acid Transporter Genes in Ricinus communis Seedlings.

    Science.gov (United States)

    Xie, Yun; Zhao, Jun-Long; Wang, Chuan-Wei; Yu, Ai-Xin; Liu, Niu; Chen, Li; Lin, Fei; Xu, Han-Hong

    2016-05-18

    Phloem-mobile insecticides are efficient for piercing and sucking insect control. Introduction of sugar or amino acid groups to the parent compound can improve the phloem mobility of insecticides, so a glycinergic-fipronil conjugate (GlyF), 2-(3-(3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)sulfinyl)-1H-pyrazole-5-yl)ureido) acetic acid, was designed and synthesized. Although the "Kleier model" predicted that this conjugate is not phloem mobile, GlyF can be continually detected during a 5 h collection of Ricinus communis phloem sap. Furthermore, an R. communis seedling cotyledon disk uptake experiment demonstrates that the uptake of GlyF is sensitive to pH, carbonyl cyanide m-chlorophenylhydrazone (CCCP), temperature, and p-chloromercuribenzenesulfonic acid (pCMBS) and is likely mediated by amino acid carrier system. To explore the roles of amino acid transporters (AATs) in GlyF uptake, a total of 62 AAT genes were identified from the R. communis genome in silico. Phylogenetic analysis revealed that AATs in R. communis were organized into the ATF (amino acid transporter) and APC (amino acid, polyaminem and choline transporter) superfamilies, with five subfamilies in ATF and two in APC. Furthermore, the expression profiles of 20 abundantly expressed AATs (cycle threshold (Ct) values AAT genes, RcLHT6, RcANT15, RcProT2, and RcCAT2, were induced by the GlyF treatment in R. communis seedlings. On the basis of the observation that the expression profile of the four candidate genes is similar to the time course observation for GlyF foliar disk uptake, it is suggested that those four genes are possible candidates involved in the uptake of GlyF. These results contribute to a better understanding of the mechanism of GlyF uptake as well as phloem loading from a molecular biology perspective and facilitate functional characterization of candidate AAT genes in future studies. PMID:27092815

  17. Uptake of amino acids in brain tumours using positron emission tomography as an indicator for assessing metabolic activity and malignancy

    International Nuclear Information System (INIS)

    Diagnosis and post-therapeutic follow-up of tumour patients necessitates morphological and particularly functional imaging methods. For the latter approach positron emission tomography has proven a valid tool for the measurement of perfusion, of energy consumption parameters such as oxygen extraction, glucose metabolism and amino acid uptake. However, neither perfusion nor energy consumption parameters have yielded unambiguous information on the clinical status of various tumours in respect of their malignancy and their growth status. It is shown in this paper that amino acid uptake seems to be a valid measure for the functional activity of tumour tissue for a broad range of neoplasms. The uptake of 11C-L-Methionine was measured in 33 patients having various brain tumours, and was compared with 6 patients who had an infarction, and with 8 patients suffering from arachnoidal cysts. The amino acid uptake correlated well with the histological grading of the tumours and the clinical status of the patient. The uptake was well differentiated against metabolically inactive lesions. Parallel investigations on the uptake mechanisms of amino acids in an animal model have shown that transport phenomena regulate the uptake rather than protein synthesis rates. However, protein synthesis may nevertheless exercise a control function on the transport process. (orig.)

  18. Biochemical Characterization of Branched Chain Amino Acids Uptake in Trypanosoma cruzi.

    Science.gov (United States)

    Manchola, Nubia C; Rapado, Ludmila N; Barisón, María J; Silber, Ariel M

    2016-05-01

    Trypanosoma cruzi is the etiological agent of Chagas disease. During its life cycle, it alternates among vertebrate and invertebrate hosts. Metabolic flexibility is a main biochemical characteristic of this parasite, which is able to obtain energy by oxidizing a variety of nutrients that can be transported from the extracellular medium. Moreover, several of these metabolites, more specifically amino acids, have a variety of functions beyond being sources of energy. Branched chain amino acids (BCAA), beyond their role in ATP production, are involved in sterol biosynthesis; for example, leucine is involved as a negative regulator of the parasite differentiation process occurring in the insect midgut. BCAA are essential metabolites in most nonphotosynthetic eukaryotes, including trypanosomes. In view of this, the metabolism of BCAA in T. cruzi depends mainly on their transport into the cell. In this work, we kinetically characterized the BCAA transport in T. cruzi epimastigotes. Our data point to BCAA as being transported by a single saturable transport system able to recognize leucine, isoleucine and valine. In view of this, we used leucine to further characterize this system. The transport increased linearly with temperature from 10 to 45 °C, allowing the calculation of an activation energy of 51.30 kJ/mol. Leucine uptake was an active process depending on ATP production and a H(+) gradient, but not on a Na(+) or K(+) gradient at the cytoplasmic membrane level. PMID:26496801

  19. Amino acid uptake in the skeletal muscle measured using [{sup 11}C]methylaminoisobutyrate (MEAIB) and PET

    Energy Technology Data Exchange (ETDEWEB)

    Asola, Markku R.; Virtanen, Kirsi A.; Peltoniemi, Pauliina; Naagren, Kjell; Yu, Meixiang; Knuuti, Juhani [Turku PET Centre, University of Turku (Finland); Mattila, Kari [Department of Central Laboratory, Turku University Central Hospital, Turku (Finland); Jyrkkioe, Sirkku [Department of Oncology, Turku University Central Hospital, Turku (Finland); Metsaerinne, Kaj [Department of Medicine, Turku University Central Hospital, 20520 Turku (Finland); Nuutila, Pirjo [Department of Medicine, Turku University Central Hospital, 20520 Turku (Finland); Turku PET Centre, University of Turku (Finland)

    2002-11-01

    An amino acid analogue, [{sup 11}C]MeAIB, recently introduced for oncological positron emission tomography (PET) studies, is a highly selective substrate for insulin-sensitive amino acid transport system A. The aim of this study was to study the uptake kinetics of [{sup 11}C]MeAIB in skeletal muscle in the fasting state and during insulin stimulation. Two dynamic PET studies were carried out in 11 healthy subjects, once in the fasting state and once during euglycaemic hyperinsulinaemia (serum insulin 67{+-}12 mU l{sup -1}). Graphical analysis was used to calculate the fractional [{sup 11}C]MeAIB uptake rate (K{sub i}). Amino acid uptake was estimated by multiplying K{sub i} by the serum amino acid concentration. After tracer injection, rapid uptake in muscle tissue was detected both in the fasting state and during insulin stimulation and femoral muscles were clearly visualised in both studies. In the graphical analysis, the volume of distribution of [{sup 11}C]MeAIB plotted against normalised plasma time yielded a linear curve (the slope of which = K{sub i}). The fractional [{sup 11}C]MeAIB uptake rate (K{sub i}) in the femoral muscle regions increased from 0.0070{+-}0.0018 min{sup -1} (mean{+-}SD) in the fasting state to 0.0079{+-}0.0020 min{sup -1} (P<0.05) during insulin stimulation. When compared with the fasting state, serum total amino acid concentration decreased from 2.49{+-}0.22 to 2.16{+-}0.18 mmol l{sup -1} (P<0.0001) and the serum concentration of six amino acids typically using system A for their transport decreased from 0.72{+-}0.1 to 0.63{+-}0.07 mmol l{sup -1} (P=0.0001) during hyperinsulinaemia. The calculated skeletal muscle total amino acid uptake and the uptake of the six amino acids typically using system A were similar in the fasting state and during insulin clamp (17.1{+-}3.2 vs 17.7{+-}3.7 {mu}mol kg{sup -1} min{sup -1}, NS, and 5.0{+-}1.3 vs 5.0{+-}1.4 {mu}mol kg{sup -1} min{sup -1}, NS, respectively). The uptake rates correlated with

  20. Excitatory amino acid-stimulated uptake of /sup 22/Na+ in primary astrocyte cultures

    Energy Technology Data Exchange (ETDEWEB)

    Kimelberg, H.K.; Pang, S.; Treble, D.H.

    1989-04-01

    In this study we have found that L-glutamic acid, as well as being taken up by a Na+-dependent mechanism, will stimulate the uptake of 22Na+ by primary astrocyte cultures from rat brain in the presence of ouabain. By simultaneously measuring the uptake of 22Na+ and L-3H-glutamate a stoichiometry of 2-3 Na+ per glutamate was measured, implying electrogenic uptake. Increasing the medium K+ concentration to depolarize the cells inhibited L-3H-glutamate uptake, while calculations of the energetics of the observed L-3H-glutamate accumulation also supported an electrogenic mechanism of at least 2 Na+:1 glutamate. In contrast, kinetic analysis of the Na+ dependence of L-3H-glutamate uptake indicated a stoichiometry of Na+ to glutamate of 1:1, but further analysis showed that the stoichiometry cannot be resolved by purely kinetic studies. Studies with glutamate analogs, however, showed that kainic acid was a very effective stimulant of 22Na+ uptake, but 3H-kainic acid showed no Na+ -dependent uptake. Furthermore, while L-3H-glutamate uptake was very sensitive to lowered temperatures, glutamate-stimulated 22Na+ uptake was relatively insensitive. These results indicate that glutamate-stimulated uptake of 22Na+ in primary astrocytes cultures cannot be explained solely by cotransport of Na+ with glutamate, and they suggest that direct kainic acid-type receptor induced stimulation of Na+ uptake also occurs. Since both receptor and uptake effects involve transport of Na+, accurate measurements of the Na+ :glutamate stoichiometry for uptake can only be done using completely specific inhibitors of these 2 systems.

  1. Excitatory amino acid-stimulated uptake of 22Na+ in primary astrocyte cultures

    International Nuclear Information System (INIS)

    In this study we have found that L-glutamic acid, as well as being taken up by a Na+-dependent mechanism, will stimulate the uptake of 22Na+ by primary astrocyte cultures from rat brain in the presence of ouabain. By simultaneously measuring the uptake of 22Na+ and L-3H-glutamate a stoichiometry of 2-3 Na+ per glutamate was measured, implying electrogenic uptake. Increasing the medium K+ concentration to depolarize the cells inhibited L-3H-glutamate uptake, while calculations of the energetics of the observed L-3H-glutamate accumulation also supported an electrogenic mechanism of at least 2 Na+:1 glutamate. In contrast, kinetic analysis of the Na+ dependence of L-3H-glutamate uptake indicated a stoichiometry of Na+ to glutamate of 1:1, but further analysis showed that the stoichiometry cannot be resolved by purely kinetic studies. Studies with glutamate analogs, however, showed that kainic acid was a very effective stimulant of 22Na+ uptake, but 3H-kainic acid showed no Na+ -dependent uptake. Furthermore, while L-3H-glutamate uptake was very sensitive to lowered temperatures, glutamate-stimulated 22Na+ uptake was relatively insensitive. These results indicate that glutamate-stimulated uptake of 22Na+ in primary astrocytes cultures cannot be explained solely by cotransport of Na+ with glutamate, and they suggest that direct kainic acid-type receptor induced stimulation of Na+ uptake also occurs. Since both receptor and uptake effects involve transport of Na+, accurate measurements of the Na+ :glutamate stoichiometry for uptake can only be done using completely specific inhibitors of these 2 systems

  2. Inhibition of Large Neutral Amino Acid Transporters Suppresses Kynurenic Acid Production Via Inhibition of Kynurenine Uptake in Rodent Brain.

    Science.gov (United States)

    Sekine, Airi; Kuroki, Yusuke; Urata, Tomomi; Mori, Noriyuki; Fukuwatari, Tsutomu

    2016-09-01

    The tryptophan metabolite, kynurenic acid (KYNA), is a preferential antagonist of the α7 nicotinic acetylcholine receptor and N-methyl-D-aspartic acid receptor at endogenous brain concentrations. Recent studies have suggested that increases of brain KYNA levels are involved in psychiatric disorders such as schizophrenia and depression, and regulation of KYNA production has become a new target for treatment of these diseases. Kynurenine (KYN), the immediate precursor of KYNA, is transported into astrocytes via large neutral amino acid transporters (LATs). In the present study, the effect of LATs regulation on KYN uptake and KYNA production was investigated in vitro and in vivo using an LATs inhibitor, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). In the in vitro study, cortical slices of rat brain were incubated with a physiological concentration of KYN and 3 µmol/L-3 mmol/L BCH. BCH inhibited KYNA production and KYN uptake in a dose-dependent manner, and their IC50 values were 90.7 and 97.4 µmol/L, respectively. In the in vivo study, mice were administered KYN (50 mg/kg BW) orally and BCH (200 mg/kg BW) intravenously. Administration of KYN increased brain KYN and KYNA levels compared with the mice treated with vehicle, whereas additional administration of BCH suppressed KYN-induced elevations in KYN and KYNA levels to 50 and 70 % in the brain. These results suggest that inhibition of LATs prevented the increase of KYNA production via blockade of KYN uptake in the brain in vitro and in vivo. LATs can be a target to modulate brain function by regulation of KYNA production in the brain. PMID:27161376

  3. Uptake of 3-[125I]iodo-α-methyl-L-tyrosine into colon cancer DLD-1 cells: characterization and inhibitory effect of natural amino acids and amino acid-like drugs

    International Nuclear Information System (INIS)

    Introduction: We examined 3-[123I]iodo-α-methyl-L-tyrosine ([123I]IMT) uptake and inhibition by amino acids and amino acid-like drugs in the human DLD-1 colon cancer cell line, to discuss correlation between the inhibition effect and structure. Methods: Expression of relevant neutral amino acid transporters was examined by real-time PCR with DLD-1 cells. The time course of [125I]IMT uptake, contributions of transport systems, concentration dependence and inhibition effects by amino acids and amino acid-like drugs (1 mM) on [125I]IMT uptake were examined. Results: Expression of system L (4F2hc, LAT1 and LAT2), system A (ATA1, ATA2) and system ASC (ASCT1) was strongly detected; system L (LAT3, LAT4) and MCT8 were weakly detected; and B0AT was not detected. [125I]IMT uptake in DLD-1 cells involved Na+-independent system L primarily and Na+-dependent system(s). Uptake of [125I]IMT in Na+-free buffer followed Michaelis-Menten kinetics, with a Km of 78 μM and Vmax of 333 pmol/106 cells per minute. Neutral D- and L-amino acids with branched or aromatic large side chains inhibited [125I]IMT uptake. Tyrosine analogues, tryptophan analogues, L-phenylalanine and p-halogeno-L-phenylalanines, and gamma amino acids [including 3,4-dihydroxy-L-phenylalanine (L-DOPA), DL-threo-β-(3,4-dihydroxyphenyl)serine (DOPS), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and 1-(aminomethyl)-cyclohexaneacetic acid] strongly inhibited [125I]IMT uptake, but L-tyrosine methyl ester and R(+)/S(-)-baclofen weakly inhibited uptake. The substrates of system ASC and A did not inhibit [125I]IMT uptake except L-serine and D/L-cysteine. Conclusions: [125I]IMT uptake in DLD-1 cells involves mostly LAT1 and its substrates' (including amino acid-like drugs derived from tyrosine, tryptophan and phenylalanine) affinity to transport via LAT1. Whether transport of gamma amino acid analogues is involved in LAT1 depends on the structure of the group corresponding to the amino acid residue. Beta-hydroxylation may

  4. Uptake of 3-[{sup 125}I]iodo-{alpha}-methyl-L-tyrosine into colon cancer DLD-1 cells: characterization and inhibitory effect of natural amino acids and amino acid-like drugs

    Energy Technology Data Exchange (ETDEWEB)

    Shikano, Naoto [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan)], E-mail: sikano@ipu.ac.jp; Ogura, Masato [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Okudaira, Hiroyuki [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan); Nakajima, Syuichi; Kotani, Takashi [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kobayashi, Masato [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan); Nakazawa, Shinya [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Baba, Takeshi; Yamaguchi, Naoto [Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kubota, Nobuo [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Iwamura, Yukio [Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kawai, Keiichi [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan)

    2010-02-15

    Introduction: We examined 3-[{sup 123}I]iodo-{alpha}-methyl-L-tyrosine ([{sup 123}I]IMT) uptake and inhibition by amino acids and amino acid-like drugs in the human DLD-1 colon cancer cell line, to discuss correlation between the inhibition effect and structure. Methods: Expression of relevant neutral amino acid transporters was examined by real-time PCR with DLD-1 cells. The time course of [{sup 125}I]IMT uptake, contributions of transport systems, concentration dependence and inhibition effects by amino acids and amino acid-like drugs (1 mM) on [{sup 125}I]IMT uptake were examined. Results: Expression of system L (4F2hc, LAT1 and LAT2), system A (ATA1, ATA2) and system ASC (ASCT1) was strongly detected; system L (LAT3, LAT4) and MCT8 were weakly detected; and B{sup 0}AT was not detected. [{sup 125}I]IMT uptake in DLD-1 cells involved Na{sup +}-independent system L primarily and Na{sup +}-dependent system(s). Uptake of [{sup 125}I]IMT in Na{sup +}-free buffer followed Michaelis-Menten kinetics, with a K{sub m} of 78 {mu}M and V{sub max} of 333 pmol/10{sup 6} cells per minute. Neutral D- and L-amino acids with branched or aromatic large side chains inhibited [{sup 125}I]IMT uptake. Tyrosine analogues, tryptophan analogues, L-phenylalanine and p-halogeno-L-phenylalanines, and gamma amino acids [including 3,4-dihydroxy-L-phenylalanine (L-DOPA), DL-threo-{beta}-(3,4-dihydroxyphenyl)serine (DOPS), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and 1-(aminomethyl)-cyclohexaneacetic acid] strongly inhibited [{sup 125}I]IMT uptake, but L-tyrosine methyl ester and R(+)/S(-)-baclofen weakly inhibited uptake. The substrates of system ASC and A did not inhibit [{sup 125}I]IMT uptake except L-serine and D/L-cysteine. Conclusions: [{sup 125}I]IMT uptake in DLD-1 cells involves mostly LAT1 and its substrates' (including amino acid-like drugs derived from tyrosine, tryptophan and phenylalanine) affinity to transport via LAT1. Whether transport of gamma amino acid analogues is

  5. [3H]-amino acid uptake and metabolic studies on Gigantocotyle explanatum and Gastrothylax crumenifer (Digenea: Paramphistomidae)

    International Nuclear Information System (INIS)

    The amphistomes Gigantocotyle explanatum and Gastrothylax crumenifer utilize leucine, alanine, proline and methionine during in vitro incubations. Autoradiography on sections of these flukes reveal a time-dependent differential incorporation of tritium-labelled amino acids in various tissues. The tegument appears to be the primary surface through which amino acids are absorbed. Following absorption, the reappearance of [3H]-leucine and [3H]-alanine on the tegumental surface during late chase periods indicates their possible involvement in tegumental secretion. A combination of diffusion and carrier-mediated uptake, possibly involving gamma-glutamyl transpeptidase, is indicated. The transport loci show differences in carrier-affinity (Kt) and maximum uptake velocities (Vmax) for amino acids under study, which suggest multiple transport molecules. Metabolic studies reveal that aspartate, alanine, ornithine, proline, leucine and methionine undergo transamination through 2-oxoglutarate-linked transaminases, distributed in the cytosolic and mitochondrial fractions of G. explanatum and G. crumenifer. With the exception of alanine transaminase, the enzyme levels in the cytosolic fraction were higher than the mitochondrial fraction of the two amphistomes. Predominantly cytosolic glutamate dehydrogenase which was comparatively higher in G. explanatum, catalyse amination of alpha-ketoglutarate. A high level of cytosolic arginase alone does not indicate a functional urea cycle. A tentative pathway of amino acid metabolism in these amphistomes is proposed

  6. The proton-coupled amino acid transporter hPAT1 is the main transporter involved in vigabatrin uptake in intestinal Caco-2 cells

    DEFF Research Database (Denmark)

    Nøhr, Martha Kampp; Hansen, Steen Honore'; Brodin, Birger;

    2012-01-01

    selected amino acids and -derivatives on the apical vigabatrin uptake in Caco-2 cells was investigated. Vigabatrin samples were analyzed using liquid chromatography (LC) coupled to a mass selective detector (MSD). Results: The uptake rate of vigabatrin in Caco-2 cells was pH-dependent. The uptake of...

  7. The role of L-type amino acid transporters in the uptake of glyphosate across mammalian epithelial tissues.

    Science.gov (United States)

    Xu, Jiaqiang; Li, Gao; Wang, Zhuoyi; Si, Luqin; He, Sijie; Cai, Jialing; Huang, Jiangeng; Donovan, Maureen D

    2016-02-01

    Glyphosate is one of the most commonly used herbicides worldwide due to its broad spectrum of activity and reported low toxicity to humans. Glyphosate has an amino acid-like structure that is highly polar and shows low bioavailability following oral ingestion and low systemic toxicity following intravenous exposures. Spray applications of glyphosate in agricultural or residential settings can result in topical or inhalation exposures to the herbicide. Limited systemic exposure to glyphosate occurs following skin contact, and pulmonary exposure has also been reported to be low. The results of nasal inhalation exposures, however, have not been evaluated. To investigate the mechanisms of glyphosate absorption across epithelial tissues, the permeation of glyphosate across Caco-2 cells, a gastrointestinal epithelium model, was compared with permeation across nasal respiratory and olfactory tissues excised from cows. Saturable glyphosate uptake was seen in all three tissues, indicating the activity of epithelial transporters. The uptake was shown to be ATP and Na(+) independent, and glyphosate permeability could be significantly reduced by the inclusion of competitive amino acids or specific LAT1/LAT2 transporter inhibitors. The pattern of inhibition of glyphosate permeability across Caco-2 and nasal mucosal tissues suggests that LAT1/2 play major roles in the transport of this amino-acid-like herbicide. Enhanced uptake into the epithelial cells at barrier mucosae, including the respiratory and gastrointestinal tracts, may result in more significant local and systemic effects than predicted from glyphosate's passive permeability, and enhanced uptake by the olfactory mucosa may result in further CNS disposition, potentially increasing the risk for brain-related toxicities. PMID:26701683

  8. Tracking amino acid's uptake into the protozoan Acanthamoeba castellanii by stable-isotope labelling and Raman spectral imaging

    Science.gov (United States)

    Naemat, Abida; Elsheikha, Hany M.; Notingher, Ioan

    2016-04-01

    The capacity of pathogens to acquire nutrients from their host cells is one of the most fundamental aspects of infection biology. Hence, measuring the patterns of nutrients' uptake by pathogens is essential for understanding the interactions of pathogens with eukaryotic host cells. In this study, we optimized a technique that allows fast and non-destructive measurement of the amino acid Phenylalanine (Phe) acquired by the trophozoite stage of the protozoan Acanthamoeba castellanii (A. castellanii) as they engage with individual human retinal pigment epithelial cells (ARPE-19). ARPE-19 host cells were pre-saturated with Deuterated Phe (L-Phe(D8)) to replace the native substrate Phe (L-Phe). The uptake of L-Phe(D8) by A. castellanii trophozoites was measured by Raman microspectroscopy. This approach allowed us to characterize the uptake patterns of this essential amino acid into A. castellanii trophozoites at a single cell level. At 24 hours post infection (PI) A. castellanii trophozoites are capable of salvaging L-Phe(D8) from host cells. The uptake pattern was time-dependent during the first 24 hours of infection and complete substitution with L-Phe(D8) in all parasites was detected at 48 hours PI. On the other hand, isolated A. castellanii trachyzoites (grown without host cells) did not show significant uptake for L-Phe(D8) from the media; only achieved an uptake ratio of 16-18% of L-Phe(D8) from the culture medium after 24 hours. These findings demonstrate the potential of combining Raman microspectroscopy and stable isotope labelling approaches to elucidate the role of metabolism in mediating A. castellanii interaction with host cells.

  9. Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

    International Nuclear Information System (INIS)

    AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

  10. Osmotically inducible uptake of betaine via amino acid transport system A in SV-3T3 cells.

    Science.gov (United States)

    Petronini, P G; De Angelis, E; Borghetti, A F; Wheeler, K P

    1994-05-15

    The osmotically inducible uptake of betaine (NNN-trimethylglycine) by SV-3T3 cells has been studied and compared with the similar process in MDCK cells. Betaine uptake by SV-3T3 cells could be described in terms of a saturable, Na(+)-dependent, component plus a small non-saturable, Na(+)-independent, component. Transport was active, producing considerable accumulation of betaine in the cells. After exposure of the cells to hypertonic conditions for 6 h, there was a marked increase in betaine uptake. Kinetic analysis indicated that this increase resulted from an increase in the Vmax. value of the saturable component, from about 88 to 185 nmol of betaine/5 min per mg of protein, the corresponding Km values of about 15 and 10 mM not being significantly different. This induction of transport activity was detectable only after about 2 h exposure of the cells to hypertonic medium, closely paralleling an induction of influx of N-methylaminoisobutyric acid, and was prevented by the presence of cycloheximide. Betaine influx was markedly inhibited by several neutral amino acids, particularly those transported by system A, such as N-methylaminoisobutyric acid and the imino acid proline. A high concentration (25 mM) of betaine also significantly inhibited the uptake of proline by SV-3T3 cells. Although very similar results were obtained with MDCK cells, prolonged exposure of cells to hypertonic conditions revealed distinct differences. When the hypertonic incubation was extended from 6 h to 24 h, betaine transport in SV-3T3 cells either remained the same or decreased, whereas it showed a further marked increase in MDCK cells, and also became sensitive to inhibition by gamma-aminobutyric acid. mRNA for the betaine transporter BGT-1 [Yamauchi, Uchida, Kwon, Preston, Brooks Robey, Garcia-Perez, Burg and Handler (1992) J. Biol. Chem. 267, 649-652] was detectable in MDCK cells exposed to hypertonic medium for 24 h, but not in SV-3T3 cells under any conditions. It is concluded that

  11. Evaluation of the Role of Mixed Amino Acids in Nitrate Uptake and Assimilation in Leafy Radish by Using 15N-Labeled Nitrate

    Institute of Scientific and Technical Information of China (English)

    LIU Xing-quan; CHEN Hui-yun; NI Qin-xue; Kyu Seung

    2008-01-01

    In this paper, the role of mixed amino acids in nitrate uptake and assimilation was evaluated in leafy radish by using 15N labeled nitrate. The mixtures of alanine, (i-alanine, aspartic acid, asparagines, glutamic acid, glutamine, and glycine were sprayed to plant leaf two or four times. The activity of the enzymes related to the process of NO3- reduction (nitrate reductase, nitrite reductase and glutamine synthetase) was affected differently depending on the application rate of mixed amino acids. Applying mixed amino acids increased the fresh weight, dry weight, and N yield. The NO3-content was reduced to 24-38%, but no significant differences were observed in amino acids and proteins. In addition, the nitrogen derived from fertilizer and the 15N-NO3-recovery rate increased to 2-8% and 15-47%, respectively. These results strongly suggest that the positive effect of mixed amino acids on nitrate uptake and assimilation might be attributed to the regulation on NO3- uptake and assimilation, but not to the preference for amino acids as sources of reduced nitrogen.

  12. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  13. Plasma amino acids

    Science.gov (United States)

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  14. The uptake in vitro of dyes, monosaccharides and amino acids by the filarial worm Brugia pahangi

    International Nuclear Information System (INIS)

    The uptake of D-glucose and L-leucine by B. pahangi was demonstrated using autoradiographic and scintillation counting techniques and incorporation into worm tissues was detected. Glucose was found to be readily incorporated in the apical, glycogen-rich areas of the myocytes of worms of all ages studied and in the uterine epithelium of the adult female. In contrast, a lower incorporation of D-glucose was found in the eggs, embryos and vas deferens and especially in the gut. The incorporation of L-leucine occurred throughout the tissue of the worms during a 30 min incubation. Labelling was also located over the surface of the cuticle of the worms, when incubated for a period of 15 to 60 min in L-[3H]leucine. Scintillation counting techniques demonstrated that there was no uptake of 14C-labelled L-glucose or sucrose by B. pahangi. The data presented on the uptake in vitro of nutrients or other compounds by infective larvae and adult stages of B. pahangi did not demonstrate an intestinal route of uptake but indicated that the transcuticular route of uptake may be employed. (author)

  15. Evaluation of cellular uptake and intracellular trafficking as determining factors of gene expression for amino acid-substituted gemini surfactant-based DNA nanoparticles

    OpenAIRE

    Singh Jagbir; Michel Deborah; Chitanda Jackson M; Verrall Ronald E; Badea Ildiko

    2012-01-01

    Abstract Background Gene transfer using non-viral vectors offers a non-immunogenic and safe method of gene delivery. Cellular uptake and intracellular trafficking of the nanoparticles can impact on the transfection efficiency of these vectors. Therefore, understanding the physicochemical properties that may influence the cellular uptake and the intracellular trafficking can aid the design of more efficient non-viral gene delivery systems. Recently, we developed novel amino acid-substituted ge...

  16. The Candida albicans GAP Gene Family Encodes Permeases Involved in General and Specific Amino Acid Uptake and Sensing

    Czech Academy of Sciences Publication Activity Database

    Kraidlová, Lucie; Van Zeebroeck, G.; Van Dijck, P.; Sychrová, Hana

    2011-01-01

    Roč. 10, č. 9 (2011), s. 1219-1229. ISSN 1535-9778 Institutional research plan: CEZ:AV0Z50110509 Keywords : GAP1 * Candida albicans * amino-acid permease * amino-acid sensing * transceptor Subject RIV: EE - Microbiology, Virology Impact factor: 3.604, year: 2011

  17. Tracing in situ amino acid uptake in plants and microbes with15N13C labelled compounds

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen; Michelsen, Anders; Jonasson, Sven Evert;

    intact amino acids. Furthermore, tannin addition tended to reduce plant uptake of label. By combining data on 15N recovery after 1 day in shoots and roots (fine and coarse) of the dominant heathland plants: the evergreen dwarf shrub Calluna vulgaris and the graminoid Deschampsia flexuosa, in soil...... microorganisms (chloroform fumigation extraction) and in soil water, we discuss the relative importance of free amino acids and ammonium as plant nutrients and microbial substrates in natural N-limited ecosystems with a high proportion of soil N held in tannin-N complexes. ...

  18. The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by C-13-labeling experiments

    DEFF Research Database (Denmark)

    Jensen, N.B.S.; Christensen, B.; Nielsen, Jette;

    2002-01-01

    Uniformly C-13 labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with C-13 disclosing a substantial de novo biosyn...

  19. Copper—Induced Changes in the Urea Uptake and Urease Activity in the Cyanobacteria Anabaena doliolum and Anacystis Nidulans:Interaction With Sulphur Containing Amino Acids

    Institute of Scientific and Technical Information of China (English)

    S.SINGH; B.B.SINGH; 等

    1995-01-01

    Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans.Copper,at and above 5μmol/L concentration,inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner,However,the urea uptake and urease activity systems in A.nidulans apeared slightly more tolerant to copper than that of A.doliolum.The inhibitory effect of copeer on urea uptake and urease activity was mitigated by sulphur containing amino acids(cystine and cysteine),however,methionine could not do so,indicating the involvement of sulfhydryl(-SH) groups in the assimilation of urea in cyanobacteria.

  20. Amino Acid Crossword Puzzle

    Science.gov (United States)

    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;…

  1. Evaluation of cellular uptake and intracellular trafficking as determining factors of gene expression for amino acid-substituted gemini surfactant-based DNA nanoparticles

    Science.gov (United States)

    2012-01-01

    Background Gene transfer using non-viral vectors offers a non-immunogenic and safe method of gene delivery. Cellular uptake and intracellular trafficking of the nanoparticles can impact on the transfection efficiency of these vectors. Therefore, understanding the physicochemical properties that may influence the cellular uptake and the intracellular trafficking can aid the design of more efficient non-viral gene delivery systems. Recently, we developed novel amino acid-substituted gemini surfactants that showed higher transfection efficiency than their parent compound. In this study, we evaluated the mechanism of cellular uptake of the plasmid/gemini surfactant/helper lipid nanoparticles and their effect on the transfection efficiency. Results Nanoparticles were incubated with Sf 1 Ep cells in the presence of different endocytic inhibitors and gene expression (interferon-γ) was measured using ELISA. Clathrin-mediated and caveolae-mediated uptake were found to be equally contributing to cellular internalization of both P/12-7NH-12/L (parent gemini surfactant) and P/12-7NGK-12/L (amino acid-substituted gemini surfactant) nanoparticles. The plasmid and the helper lipid were fluorescently tagged to track the nanoparticles inside the cells, using confocal laser scanning microscopy. Transmission electron microscopy images showed that the P/12-7NGK-12/L particles were cylindrical while the P/12-7NH-12/L particles were spherical which may influence the cellular uptake behaviour of these particles. Dye exclusion assay and pH-titration of the nanoparticles suggested that high buffering capacity, pH-dependent increase in particle size and balanced DNA binding properties may be contributing to a more efficient endosomal escape of P/12-7NGK-12/L compared to the P/12-7NH-12/L nanoparticles, leading to higher gene expression. Conclusion Amino-acid substitution in the spacer of gemini surfactant did not alter the cellular uptake pathway, showing similar pattern to the

  2. Evaluation of cellular uptake and intracellular trafficking as determining factors of gene expression for amino acid-substituted gemini surfactant-based DNA nanoparticles

    Directory of Open Access Journals (Sweden)

    Singh Jagbir

    2012-02-01

    Full Text Available Abstract Background Gene transfer using non-viral vectors offers a non-immunogenic and safe method of gene delivery. Cellular uptake and intracellular trafficking of the nanoparticles can impact on the transfection efficiency of these vectors. Therefore, understanding the physicochemical properties that may influence the cellular uptake and the intracellular trafficking can aid the design of more efficient non-viral gene delivery systems. Recently, we developed novel amino acid-substituted gemini surfactants that showed higher transfection efficiency than their parent compound. In this study, we evaluated the mechanism of cellular uptake of the plasmid/gemini surfactant/helper lipid nanoparticles and their effect on the transfection efficiency. Results Nanoparticles were incubated with Sf 1 Ep cells in the presence of different endocytic inhibitors and gene expression (interferon-γ was measured using ELISA. Clathrin-mediated and caveolae-mediated uptake were found to be equally contributing to cellular internalization of both P/12-7NH-12/L (parent gemini surfactant and P/12-7NGK-12/L (amino acid-substituted gemini surfactant nanoparticles. The plasmid and the helper lipid were fluorescently tagged to track the nanoparticles inside the cells, using confocal laser scanning microscopy. Transmission electron microscopy images showed that the P/12-7NGK-12/L particles were cylindrical while the P/12-7NH-12/L particles were spherical which may influence the cellular uptake behaviour of these particles. Dye exclusion assay and pH-titration of the nanoparticles suggested that high buffering capacity, pH-dependent increase in particle size and balanced DNA binding properties may be contributing to a more efficient endosomal escape of P/12-7NGK-12/L compared to the P/12-7NH-12/L nanoparticles, leading to higher gene expression. Conclusion Amino-acid substitution in the spacer of gemini surfactant did not alter the cellular uptake pathway, showing similar

  3. Regulations of essential amino acids and proteomics of bacterial endophytes Sphingomonas sp. Lk11 during cadmium uptake.

    Science.gov (United States)

    Khan, Abdul Latif; Ullah, Ihsan; Hussain, Javid; Kang, Sang-Mo; Al-Harrasi, Ahmed; Al-Rawahi, Ahmed; Lee, In-Jung

    2016-07-01

    Endophytic bacteria have been recently known for their potential to bioaccumulate metal from contaminated mediums. However, little is known about the physiological responses of phytohormone producing (gibberellins and auxins) endophytes during metal stressed environment. Endophytic bacteria Sphingomonas sp. LK11 was assessed for metals bioaccumulation and its physiological responses towards metal stress. The endophyte was grown in cadmium (Cd), zinc (Zn), aluminum (Al), manganese (Mn), and copper (Cu) contaminated mediums. The results revealed significantly higher endophytic growth potentials in Cd, Cu and Zn contaminations; however, the bio-accumulation rate of Cd was more prolific as compared to Zn and Cu. Interestingly, the SDS-PAGE profile showed increased expressions of proteins in Zn and Cu than in Cd. A similar attenuate response of amino acids was also observed for Cd than in case of Zn and Cu. Only asparagine, glutamate and proline showed significant impact in Cd while Cu and Zn had significantly higher responses of almost all amino acids. Detailed protein profile showed the activation of chaperone, antioxidative and detoxification proteins. Increased regulations of oxidoreductases, superoxide dismutase, thioredoxin, malate dehydrogenase, 2-oxoisovalerate dehydrogenase, 2-oxoisovalerate dehydrogenase, and dihydrolipoyl dehydrogenase were observed. The cellular defense-related protein responses were potent against Cd stress. The results conclude that Sphingomonas sp. LK11 reprogram its amino acids and proteomic expressions and maintain a steady growth during Cd stress. Using such phytohromones producing endophytic bacterium can be ideal approach to increase the phytoextraction potential of metal remediating plants. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 887-896, 2016. PMID:25533023

  4. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  5. High-Speed Microdialysis-Capillary Electrophoresis Assays for Measuring Branched Chain Amino Acid Uptake in 3T3-L1 cells.

    Science.gov (United States)

    Harstad, Rachel K; Bowser, Michael T

    2016-08-16

    We have developed a high-throughput microdialysis-capillary electrophoresis (MD-CE) assay for monitoring branched chain amino acid (BCAA) uptake/release dynamics in 3T3-L1 cells. BCAAs (i.e., isoleucine, leucine, and valine) and their downstream metabolites (i.e., alanine, glutamine, and glutamate) are important indicators of adipocyte lipogenesis. To perform an analysis, amino acids were sampled using microdialysis, fluorescently labeled in an online reaction, separated using CE, and detected using laser-induced fluorescence (LIF) in a sheath flow cuvette. Separation conditions were optimized for the resolution of the BCAAs isoleucine, leucine, and valine, as well as 13 other amino acids, including ornithine, alanine, glutamine, and glutamate. CE separations were performed in <30 s, and the temporal resolution of the online MD-CE assay was <60 s. Limits of detection (LOD) were 400, 200, and 100 nM for isoleucine, leucine, and valine, respectively. MD-CE dramatically improved throughput in comparison to traditional offline CE methods, allowing 8 replicates of 15 samples (i.e., 120 analyses) to be assayed in <120 min. The MD-CE assay was used to assess the metabolism dynamics of 3T3-L1 cells over time, confirming the utility of the assay. PMID:27398773

  6. Influence of protein source on amino acid uptake patterns and protein utilization in rainbow trout Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Rolland, Marine; Holm, Jørgen; Dalsgaard, Anne Johanne Tang;

    first part, oxygen consumption was recorded continuously, while water was sampled as detailed above and analyzed for ammonium and urea content. The second part of the experiment was designed to collect blood samples. After the feeding treatment fish were held in separate containers for the above......Matrixes of different protein sources (fish and plant products) combined with the use of crystalline amino acids allow for formulation of diets that meet fish requirements with little or no effect on protein digestibility and/or feed intake. Despite this, a total or partial replacement of fish meal...... treatment) were placed in individual chambers for 48h. Blood and water samples were collected at time 0 and then at 2, 4, 6, 8, 12, 20, 32 and 48 hours post feeding. The protocol was repeated until 8 replicates per treatment were obtained The results were obtained through 2 separate experiments. In the...

  7. Brain and brain tumor uptake of L-3-[123I]iodo-alpha-methyl tyrosine: competition with natural L-amino acids

    International Nuclear Information System (INIS)

    SPECT studies with L-3-[123I]iodo-alpha-methyl tyrosine (IMT) were carried out in 10 patients with different types of brain tumors--first under fasting conditions (basal) and a week later during intravenous infusion of a mixture of naturally-occurring L-amino acids (AA load). An uptake index (UI) was calculated by dividing tissue count rates by the integral of plasma count rates. The UI decreased by 45.6% ± 15.4% (n = 10, p less than 0.001) for normal brain and by 53.2% ± 14.1% for gliomas (n = 5, p less than 0.01) during AA load compared to basal conditions, while two meningiomas and a metastasis showed only a minor decrease (23.9 ± 5.7%, n.s.). Two pituitary adenomas could not be delineated on the SPECT scans. These data indicate that IMT competes with naturally-occurring L-amino acids for transport into normal brain and gliomas. Transport characteristics of IMT into tumors of nonglial origin appear to be different from those of gliomas. For both types of tumors, it is advisable to perform IMT-SPECT under fasting conditions

  8. Amino acid analysis.

    Science.gov (United States)

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  9. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...

  10. Microfluidics in amino acid analysis.

    Science.gov (United States)

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  11. Amino Acids from a Comet

    Science.gov (United States)

    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. Main: Amino acid Analysis [KOME

    Lifescience Database Archive (English)

    Full Text Available Amino acid Analysis UniProt search ... blastx result Result of blastx search ... against UniProt protein ... database kome_uniprot_search _blastx_result.zip kome_uniprot_search _blastx_resul ...

  13. Main: Amino acid Analysis [KOME

    Lifescience Database Archive (English)

    Full Text Available Amino acid Analysis SwissProt search ... result Result of blastx search ... against SwissProt protein da ... tabase kome_swissprot_search _result.zip kome_swissprot_search _result ...

  14. Branched-Chain Amino Acids

    Czech Academy of Sciences Publication Activity Database

    Pátek, Miroslav

    Berlin : Springer-Verlag Berlin Heidelberg, 2007, s. 129-162. ISBN 978-3-540-48595-7 Institutional research plan: CEZ:AV0Z50200510 Keywords : amino acids * homologous reactions Subject RIV: EE - Microbiology, Virology

  15. Branched-Chain Amino Acids

    Directory of Open Access Journals (Sweden)

    Matteo Ghiringhelli

    2015-07-01

    Full Text Available Our study is focused on evaluation and use of the most effective and correct nutrients. In particular, our attention is directed to the role of certain amino acids in cachectic patients.During parenteral nutrition in humans, physician already associates in the PN-bags different formulations including amino acids, lipids and glucose solutions or essential amino acids solution alone or exclusively branched-chain amino acids (BCAA. Studies investigated the effects of dietary BCAA ingestion on different diseases and conditions such as obesity and metabolic disorders, liver disease, muscle atrophy, cancer, impaired immunity or injuries (surgery, trauma, burns, and sepsis. BCAAs have been shown to affect gene expression, protein metabolism, apoptosis and regeneration of hepatocytes, and insulin resistance. They have also been shown to inhibit the proliferation of liver cancer cells in vitro, and are essential for lymphocyte proliferation and dendritic cell maturation. Oral or parenteral administration of these three amino acids will allow us to evaluate the real efficacy of these compounds during a therapy to treat malnutrition in subjects unable to feed themselves.

  16. New 2-nitroimidazole analogues of amino acids with a free amino function

    International Nuclear Information System (INIS)

    In continuation of an approach to utilize amino acid transport mechanism for preferential uptake of the 2-nitroimidazole derivatives by the solid tumors, the authors now report the synthesis of new amino acid analogues that have a free amino function. The carboxy group of the amino acid is attached through an amide bond to the 2-nitroimidazole moiety. These agents were synthesized by initially reacting a t-butyloxycaronyl amino acid with 2-nitroimidazole-1-ethylamine and then deblocking with trifluoroacetic acid. The newly synthesized amino acid analogues were nontoxic against Chinese hamster (V-79) cells up to a concentration of 5mM when exposed for a 2 hr period. These agents were significantly more active than the 2-nitroimidazole amino acid analogues with a free carboxylic acid function. The phenylalanine analogue was one of the most active sensitizer producing an enhancement ratio (ER) of 2.0 at 0.5 mM. The sensitizing ability increased as a function of concentration achieving an ER of 2.2 at 1.0 mM. These preliminary results suggest that the amino acid analogues with a free amino function, are effective sensitizers and because of their low partition coefficient, may be considered potentially less neurotoxic than misonidazole

  17. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks. PMID:21120449

  18. Role of CCN2 in Amino Acid Metabolism of Chondrocytes.

    Science.gov (United States)

    Murase, Yurika; Hattori, Takako; Aoyama, Eriko; Nishida, Takashi; Maeda-Uematsu, Aya; Kawaki, Harumi; Lyons, Karen M; Sasaki, Akira; Takigawa, Masaharu; Kubota, Satoshi

    2016-04-01

    CCN2/connective tissue growth factor (CTGF) is a multi-functional molecule that promotes harmonized development and regeneration of cartilage through its matricellular interaction with a variety of extracellular biomolecules. Thus, deficiency in CCN2 supply profoundly affects a variety of cellular activities including basic metabolism. A previous study showed that the expression of a number of ribosomal protein genes was markedly enhanced in Ccn2-null chondrocytes. Therefore, in this study, we analyzed the impact of CCN2 on amino acid and protein metabolism in chondrocytes. Comparative metabolome analysis of the amino acids in Ccn2-null and wild-type mouse chondrocytes revealed stable decreases in the cellular levels of all of the essential amino acids. Unexpectedly, uptake of such amino acids was rather enhanced in Ccn2-null chondrocytes, and the addition of exogenous CCN2 to human chondrocytic cells resulted in decreased amino acid uptake. However, as expected, amino acid consumption by protein synthesis was also accelerated in Ccn2-null chondrocytes. Furthermore, we newly found that expression of two genes encoding two glycolytic enzymes, as well as the previously reported Eno1 gene, was repressed in those cells. Considering the impaired glycolysis and retained mitochondrial membrane potential in Ccn2-null chondrocytes, these findings suggest that Ccn2 deficiency induces amino acid shortage in chondrocytes by accelerated amino acid consumption through protein synthesis and acquisition of aerobic energy. Interestingly, CCN2 was found to capture such free amino acids in vitro. Under physiological conditions, CCN2 may be regulating the levels of free amino acids in the extracellular matrix of cartilage. J. Cell. Biochem. 117: 927-937, 2016. © 2015 Wiley Periodicals, Inc. PMID:26364758

  19. [Inherited amino acid transport disorders].

    Science.gov (United States)

    Igarashi, Y; Tada, K

    1992-07-01

    Disorders due to inherited amino acids transport defect are reviewed. The disorders were categorized into three types of transport defects, namely, brush-border membrane of epithelial cells of small intestine and kidney tubules (Hartnup disease, blue diaper syndrome, cystinuria, iminoglycinuria and lysine malabsorption syndrome), basolateral membrane (lysinuric protein intolerance) and membrane of intracellular organelles (cystinosis and hyperornitinemia-hyperammonemia-homocitrullinuria syndrome). Pathogenesis, clinical feature, laboratory findings, diagnosis, genetics and treatment of these disorders are described, briefly. There is not much data for the transport systems themselves, so that further investigation in molecular and gene levels for transport systems is necessary to clarify the characteristics of the transport and heterogeneity of phenotypes in inherited amino acids transport disorders. PMID:1404888

  20. Asparagine promotes cancer cell proliferation through use as an amino acid exchange factor

    Science.gov (United States)

    Krall, Abigail S.; Xu, Shili; Graeber, Thomas G.; Braas, Daniel; Christofk, Heather R.

    2016-01-01

    Cellular amino acid uptake is critical for mTOR complex 1 (mTORC1) activation and cell proliferation. However, the regulation of amino acid uptake is not well-understood. Here we describe a role for asparagine as an amino acid exchange factor: intracellular asparagine exchanges with extracellular amino acids. Through asparagine synthetase knockdown and altering of media asparagine concentrations, we show that intracellular asparagine levels regulate uptake of amino acids, especially serine, arginine and histidine. Through its exchange factor role, asparagine regulates mTORC1 activity and protein synthesis. In addition, we show that asparagine regulation of serine uptake influences serine metabolism and nucleotide synthesis, suggesting that asparagine is involved in coordinating protein and nucleotide synthesis. Finally, we show that maintenance of intracellular asparagine levels is critical for cancer cell growth. Collectively, our results indicate that asparagine is an important regulator of cancer cell amino acid homeostasis, anabolic metabolism and proliferation. PMID:27126896

  1. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. The quantitative assessment of the role played by basic amino acid clusters in the nuclear uptake of human ribosomal protein L7

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Lin-Ru [Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC (China); Chou, Chang-Wei [Institute of Clinical Dentistry Science, National Yang-Ming University, Taipei, Taiwan, ROC (China); Lee, I-Fang; Kirby, Ralph [Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC (China); Lin, Alan, E-mail: alin@ym.edu.tw [Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC (China); Institute of Clinical Dentistry Science, National Yang-Ming University, Taipei, Taiwan, ROC (China)

    2013-02-15

    In this study, we used a multiple copy (EGFP){sub 3} reporter system to establish a numeric nuclear index system to assess the degree of nuclear import. The system was first validated by a FRAP assay, and then was applied to evaluate the essential and multifaceted nature of basic amino acid clusters during the nuclear import of ribosomal protein L7. The results indicate that the sequence context of the basic cluster determines the degree of nuclear import, and that the number of basic residues in the cluster is irrelevant; rather the position of the pertinent basic residues is crucial. Moreover, it also found that the type of carrier protein used by basic cluster has a great impact on the degree of nuclear import. In case of L7, importin β2 or importin β3 are preferentially used by clusters with a high import efficiency, notwithstanding that other importins are also used by clusters with a weaker level of nuclear import. Such a preferential usage of multiple basic clusters and importins to gain nuclear entry would seem to be a common practice among ribosomal proteins in order to ensure their full participation in high rate ribosome synthesis. - Highlights: ► We introduce a numeric index system that represents the degree of nuclear import. ► The rate of nuclear import is dictated by the sequence context of the basic cluster. ► Importin β2 and β3 were mainly responsible for the N4 mediated nuclear import.

  4. Microbial Products Trigger Amino Acid Exudation from Plant Roots1

    Science.gov (United States)

    Phillips, Donald A.; Fox, Tama C.; King, Maria D.; Bhuvaneswari, T.V.; Teuber, Larry R.

    2004-01-01

    Plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. The dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. We find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 μm) exceed efflux rates by 5% to 545% in roots of alfalfa (Medicago sativa), Medicago truncatula, maize (Zea mays), and wheat (Triticum aestivum). Several microbial products, which are produced by common soil microorganisms such as Pseudomonas bacteria and Fusarium fungi, significantly enhanced the net efflux (i.e. exudation) of amino acids from roots of these four plant species. In alfalfa, treating roots with 200 μm phenazine, 2,4-diacetylphloroglucinol, or zearalenone increased total net efflux of 16 amino acids 200% to 2,600% in 3 h. Data from 15N tests suggest that 2,4-diacetylphloroglucinol blocks amino acid uptake, whereas zearalenone enhances efflux. Thus, amino acid exudation under normal conditions is a phenomenon that probably reflects both active manipulation and passive uptake by microorganisms, as well as diffusion and adsorption to soil, all of which help overcome the innate capacity of plant roots to reabsorb amino acids. The importance of identifying potential enhancers of root exudation lies in understanding that such compounds may represent regulatory linkages between the larger soil food web and the internal carbon metabolism of the plant. PMID:15347793

  5. INTERACTIONS BETWEEN SOIL TEMPERATURE AND PLANT GROWTH STAGE ON NITROGEN UPTAKE AND AMINO ACID CONTENT OF APPLE NURSERY STOCK DURING EARLY SPRING GROWTH

    Science.gov (United States)

    In the spring, nitrogen (N) uptake by apple roots is known to be delayed about three weeks after bud break. We used one-year-old 'Fuji' (Malus domestica Borkh) on M26 bare-root apple trees to determine whether timing of N uptake in the spring is dependant solely on the growth st...

  6. The putative Cationic Amino acid Transporter 9 is targeted to vesicles and may be involved in plant amino acid homeostasis

    Directory of Open Access Journals (Sweden)

    Huaiyu eYang

    2015-04-01

    Full Text Available Amino acids are major primary metabolites. Their uptake, translocation, compartmentation and re-mobilization require a diverse set of cellular transporters. Here, the broadly expressed gene product of CATIONIC AMINO ACID TRANSPORTER 9 (CAT9 was identified as mainly localized to vesicular membranes that are involved in vacuolar trafficking, including those of the trans-Golgi network. In order to probe whether and how these compartments are involved in amino acid homeostasis, a loss-of-function cat9-1 mutant and ectopic over-expressor plants were isolated. Under restricted nitrogen supply in soil, cat9-1 showed a chlorotic phenotype, which was reversed in the over-expressors. The total soluble amino acid pools were affected in the mutants, but this was only significant under poor nitrogen supply. Upon nitrogen starvation, the major soluble amino acid leaf pools decreased. This decrease was lower in cat9-1 and augmented in the over-expressor. Over-expression generally affected total soluble amino acid concentrations and finally improved the survival upon severe nitrogen starvation. The results potentially identify a novel function of vesicular amino acid transport mediated by CAT9 in the cellular nitrogen-dependent amino acid homeostasis.

  7. Amino acid properties conserved in molecular evolution.

    Directory of Open Access Journals (Sweden)

    Witold R Rudnicki

    Full Text Available 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.

  8. Pairwise amino acid secondary structural propensities

    Science.gov (United States)

    Chemmama, Ilan E.; Chapagain, Prem P.; Gerstman, Bernard S.

    2015-04-01

    We investigate the propensities for amino acids to form a specific secondary structure when they are paired with other amino acids. Our investigations use molecular dynamics (MD) computer simulations, and we compare the results to those from the Protein Data Bank (PDB). Proper comparison requires weighting of the MD results in a manner consistent with the relative frequency of appearance in the PDB of each possible pair of amino acids. We find that the propensity for an amino acid to assume a secondary structure varies dramatically depending on the amino acid that is before or after it in the primary sequence. This cooperative effect means that when selecting amino acids to facilitate the formation of a secondary structure in peptide engineering experiments, the adjacent amino acids must be considered. We also examine the preference for a secondary structure in bacterial proteins and compare the results to those of human proteins.

  9. NI-37INCREASED CEREBRAL AMINO ACID UPTAKE DURING AND AFTER EPILEPTIC DISORDERS MIMICS BRAIN TUMOR IN 18F-FET PET

    OpenAIRE

    Hutterer, Markus; Krenn, Yvonne; Kunz, Alexander; McCoy, Marc; Egger, Barbara; Schröder, Michael; Wendl, Christina; Marienhagen, Jörg; Fritsch, Brita; Urbach, Horst; Meyer, Philipp T; Galldiks, Norbert; Langen, Karl-Josef; Hau, Peter; Trinka, Eugen

    2014-01-01

    BACKGROUND: O-(2-[F-18]fluoroethyl)-L-tyrosine (18F-FET) PET has become an important diagnostic tool in addition to standard MRI to delineate cerebral gliomas. However, 18F-FET uptake has also been observed in non-tumoral lesions. METHODS AND RESULTS: We report on abnormal non-tumoral 18F-FET uptake in 6 patients with epileptic disorders: Patients A-C with clinically stable anaplastic astrocytoma over years, Patient D with anaplastic oligodendroglioma with stable residual tumor, Patient E wit...

  10. Effect of plant proteins and crystalline amino acid supplementation on postprandial plasma amino acid profiles and metabolic response in rainbow trout (Oncorhynchus mykiss)

    DEFF Research Database (Denmark)

    Rolland, Marine; Larsen, Bodil Katrine; Holm, Jørgen;

    2015-01-01

    The use of aquafeeds formulated with plant protein sources supplemented with crystalline amino acids (CAAs) is believed to influence amino acid (AA) uptake patterns and AA metabolic fate. Oxygen consumption and ammonia excretion rates were measured in rainbow trout (468.5 +/- A 86.5 g) force fed 0...

  11. Indigenous amino acids in primitive CR meteorites

    CERN Document Server

    Martins, Z; Orzechowska, G E; Fogel, M L; Ehrenfreund, P

    2008-01-01

    CR meteorites are among the most primitive meteorites. In this paper, 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. EET92042, GRA95229 and GRO95577 were analyzed for their amino acid content using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatographymass spectrometry (GC-MS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations ranging from 180 parts-per-million (ppm) to 249 ppm. GRO95577, however, is depleted in amino acids. The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the alpha-amino acids glycine, isovaline, alpha-aminoisobutyric acid (alpha-AIB), and alanine, with delta13C values ranging from +31.6per mil to +50.5per mil. The carbon isotope results together with racemic enantiomeric ratios determined for most amino acids strongly i...

  12. Amino acids in the Tagish Lake Meteorite

    Science.gov (United States)

    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.

  13. α-Amino Acid-Isosteric α-Amino Tetrazoles.

    Science.gov (United States)

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

    2016-02-24

    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

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

    Science.gov (United States)

    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. PMID:25527119

  15. Synthesis of Chiral Amino Cyclic Phosphoric Acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Chirai amino cyclic phosphoric acids, 5-amino-2-hydroxy-4- (4-nitrophenyl)-l, 3,2-dioxaphospho- rinane 2-oxide and 2-hydroxy-4- (4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64. 2% and 72. 8% respectively) from 2-amino-l-aryl-l,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

  16. Microbial production of natural poly amino acid

    Institute of Scientific and Technical Information of China (English)

    SHI Feng; XU ZhiNan; CEN PeiLin

    2007-01-01

    Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ε-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

  17. 6th Amino Acid Assessment Workshop

    Science.gov (United States)

    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, ...

  18. Human Protein and Amino Acid Requirements.

    Science.gov (United States)

    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. PMID:26796095

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

    Science.gov (United States)

    2010-07-01

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

  20. Synthesis of β-Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    Zhao Yonghua; Ma Zhihua; Jiang Nan; Wang Jianbo

    2004-01-01

    In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area.

  1. Genetics of Amino Acid Taste and Appetite.

    Science.gov (United States)

    Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K

    2016-07-01

    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

  2. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  3. Amino acid decarboxylations produced by lipid-derived reactive carbonyls in amino acid mixtures.

    Science.gov (United States)

    Hidalgo, Francisco J; León, M Mercedes; Zamora, Rosario

    2016-10-15

    The formation of 2-phenylethylamine and phenylacetaldehyde in mixtures of phenylalanine, a lipid oxidation product, and a second amino acid was studied to determine the role of the second amino acid in the degradation of phenylalanine produced by lipid-derived reactive carbonyls. The presence of the second amino acid usually increased the formation of the amine and reduced the formation of the Strecker aldehyde. The reasons for this behaviour seem to be related to the α-amino group and the other functional groups (mainly amino or similar groups) present in the side-chain of the amino acid. These groups are suggested to modify the lipid-derived reactive carbonyl but not the reaction mechanism because the Ea of formation of both 2-phenylethylamine and phenylacetaldehyde remained unchanged in all studied systems. All these results suggest that the amine/aldehyde ratio obtained by amino acid degradation can be modified by adding free amino acids during food formulation. PMID:27173560

  4. Synthesis of Li-Al layered double hydroxide intercalated with amino tris(methylene phosphonic acid) and kinetic and equilibrium studies of the uptake of Nd3+ and Sr2+ ions

    Science.gov (United States)

    Kameda, Tomohito; Shinmyou, Tetsu; Yoshioka, Toshiaki

    2016-03-01

    A Li-Al layered double hydroxide intercalated with amino tris(methylene phosphonic acid) (AMP·Li-Al LDH) was synthesized by the drop-wise addition of an Al-containing solution to a Li-AMP solution at a constant pH of 8.0. The AMP·Li-Al LDH was found to take up Nd3+ and Sr2+ ions from aqueous solutions; this phenomenon was attributable to the metal-chelating functionality of the AMP ions in the interlayers of the AMP·Li-Al LDH. Further, the AMP·Li-Al LDH was found to take up Nd3+ ions preferentially than Sr2+ ions. This was attributable to the stability of the Nd-AMP complex being higher than that of the Sr-AMP complex. The mass-transfer-controlled shrinking-core model could describe the uptake behavior better than the surface-reaction-control model. The AMP ions in the AMP·Li-Al LDH interlayers rapidly formed chelate complexes with the Nd3+ or Sr2+ ions. As a result, the transfer of Nd3+ and Sr2+ ions through the product layer was the rate-limiting step. Furthermore, this reaction could be explained by a Langmuir-type adsorption mechanism, indicating that it involved chemical adsorption; this was consistent with the formation of chelate complexes between Nd3+ and Sr2+ ions and the AMP ions in the interlayers of the AMP·Li-Al LDH.

  5. Acute supplementation of amino acids increases net protein accretion in IUGR fetal sheep

    OpenAIRE

    Brown, Laura D.; Rozance, Paul J.; Thorn, Stephanie R.; FRIEDMAN, Jacob E.; Hay, William W.

    2012-01-01

    Placental insufficiency decreases fetal amino acid uptake from the placenta, plasma insulin concentrations, and protein accretion, thus compromising normal fetal growth trajectory. We tested whether acute supplementation of amino acids or insulin into the fetus with intrauterine growth restriction (IUGR) would increase net fetal protein accretion rates. Late-gestation IUGR and control (CON) fetal sheep received acute, 3-h infusions of amino acids (with euinsulinemia), insulin (with euglycemia...

  6. Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Javakhishvili, Irakli; Han, Junyoung;

    2016-01-01

    the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

  7. Amino Acid Stability in the Early Oceans

    Science.gov (United States)

    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.

  8. Distribution of Amino Acids in Lunar Regolith

    Science.gov (United States)

    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.

  9. Hierarchical amino acid utilization and its influence on fermentation dynamics: rifamycin B fermentation using Amycolatopsis mediterranei S699, a case study

    DEFF Research Database (Denmark)

    Bapat, Prashant Madhusudhan; Das, D.; Sohoni, Sujata Vijay; Wangikar, Pramod

    2006-01-01

    Background: Industrial fermentation typically uses complex nitrogen substrates which consist of mixture of amino acids. The uptake of amino acids is known to be mediated by several amino acid transporters with certain preferences. However, models to predict this preferential uptake are not...... predicted simultaneous uptake of amino acids at low cas concentrations and sequential uptake at high cas concentrations. The simulated profile of the key enzymes implies the presence of specific transporters for small groups of amino acids. Conclusion: The work demonstrates utility of the cybernetic model...

  10. Amino Acid Degradation after Meteoritic Impact Simulation

    Science.gov (United States)

    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.

  11. Cytokines: muscle protein and amino acid metabolism

    DEFF Research Database (Denmark)

    van Hall, Gerrit

    2012-01-01

    raises TNF-α and IL-6 to moderate levels, has only identified IL-6 as a potent cytokine, decreasing systemic amino acid levels and muscle protein metabolism. The marked decrease in circulatory and muscle amino acid concentrations was observed with a concomitant reduction in both the rates of muscle...... IL-6 on the regulation of muscle protein metabolism but indirectly via IL-6 reducing amino acid availability. SUMMARY: Recent studies suggest that the best described cytokines TNF-α and IL-6 are unlikely to be the major direct mediators of muscle protein loss in inflammatory diseases. However, these...

  12. Amino acid analysis for pharmacopoeial purposes.

    Science.gov (United States)

    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. PMID:27154660

  13. Excitatory amino acid transporters as potential drug targets

    DEFF Research Database (Denmark)

    Bunch, Lennart; Erichsen, Mette Navy; Jensen, Anders Asbjørn

    2009-01-01

    BACKGROUND: Excitatory amino acid transporters (EAATs) are transmembrane proteins responsible for the uptake of (S)-glutamate (Glu) from the synaptic cleft, thereby terminating the glutamatergic neurotransmitter signal. Today five subtypes have been identified. Except for EAAT2, their individual ...... and detailed understanding of EAATs be obtained. Thus we encourage collaboration between organic chemists and molecular pharmacologists, who, together, may pave the way for new EAAT ligands of importance....

  14. Effect of amino acids and amino acid derivatives on crystallization of hemoglobin and ribonuclease A

    International Nuclear Information System (INIS)

    The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins

  15. Effect of amino acids and amino acid derivatives on crystallization of hemoglobin and ribonuclease A

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Len, E-mail: len@ksc.kwansei.ac.jp; Kobayashi, Toyoaki [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan); Shiraki, Kentaro [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Yamaguchi, Hiroshi [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan)

    2008-05-01

    The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins.

  16. D-amino acids trigger biofilm disassembly.

    Science.gov (United States)

    Kolodkin-Gal, Ilana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard

    2010-04-30

    Bacteria form communities known as biofilms, which disassemble over time. In our studies outlined here, we found that, before biofilm disassembly, Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine, and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofilms in the presence of D-amino acids contained alterations in a protein (YqxM) required for the formation and anchoring of the fibers to the cell. D-amino acids also prevented biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa. D-amino acids are produced by many bacteria and, thus, may be a widespread signal for biofilm disassembly. PMID:20431016

  17. Neutron inelastic scattering from amino acids

    International Nuclear Information System (INIS)

    Neutron incoherent inelastic scattering technique is used for studying the extensive hydrogen bonding that connects the molecules together and gives the structure cohesion in three dimension in amino acids. Results on five amino acids namely, α-glycine, DL-alanine, L-valine, L-tyrosine and L-phenyl-alanine having different side groups are reported and compared with those from other methods. The main emphasis is on the torsional motions of NH3+ and CH3 groups. (K.B.)

  18. Uptake of plasmid deoxyribonucleic acid by Haemophilus.

    OpenAIRE

    Gromkova, R; Goodgal, S

    1981-01-01

    The uptake of circular and linear plasmid RSF0885 deoxyribonucleic acids, (DNAs) obtained from Haemophilus parainfluenzae 14, in both homologous and heterologous recipients was studied and compared with that of chromosomal DNA. High concentrations of divalent cations stimulated the uptake of either circular or linear plasmid DNA in H. parainfluenzae 14 competent cells but did not affect the uptake of chromosomal DNA. The biological activity of linear plasmid DNA was similar to that of circula...

  19. Amino Acid Patterns around Disulfide Bonds

    Directory of Open Access Journals (Sweden)

    Brett Drury

    2010-11-01

    Full Text Available Disulfide bonds provide an inexhaustible source of information on molecular evolution and biological specificity. In this work, we described the amino acid composition around disulfide bonds in a set of disulfide-rich proteins using appropriate descriptors, based on ANOVA (for all twenty natural amino acids or classes of amino acids clustered according to their chemical similarities and Scheffé (for the disulfide-rich proteins superfamilies statistics. We found that weakly hydrophilic and aromatic amino acids are quite abundant in the regions around disulfide bonds, contrary to aliphatic and hydrophobic amino acids. The density distributions (as a function of the distance to the center of the disulfide bonds for all defined entities presented an overall unimodal behavior: the densities are null at short distances, have maxima at intermediate distances and decrease for long distances. In the end, the amino acid environment around the disulfide bonds was found to be different for different superfamilies, allowing the clustering of proteins in a biologically relevant way, suggesting that this type of chemical information might be used as a tool to assess the relationship between very divergent sets of disulfide-rich proteins.

  20. Effects of Exogenous Amino Acids on the Contents of Amino Acids in Tobacco Leaves

    Institute of Scientific and Technical Information of China (English)

    WU Xue-ping; LIU Guo-shun; ZHU Kai; PENG Sa; GUO Qiao-yan

    2005-01-01

    The effect of three amino acids on the growth of flue-cured tobacco was studied with water culture. The results showed that the three amino acids improved the growth of flue-cured tobacco and increased the contents of chlorophyll a,chlorophyll b and carotenoid in tobacco. At the same time, the activities of NR (nitrate reductase), INV(invertase) and root growth activity were also significantly enhanced. The exogenous glutamic, aspartate and phenylalanine all increased the amino acid contents of tobacco leaves. Of these three amino acids, glutamic had the greatest effect, the next was aspartate,and phenylalanine had the least effect. These three amino acids all had significantly increased the accumulation of amino acids in the leaves of individual plants of tobacco; and the magnitude of accumulation indicated aspartate > glutamic >phenylalanine.

  1. D-Amino acid oxidase: new findings.

    Science.gov (United States)

    Pilone, M S

    2000-11-01

    The most recent research on D-amino acid oxidases and D-amino acid metabolism has revealed new, intriguing properties of the flavoenzyme and enlighted novel biotechnological uses of this catalyst. Concerning the in vivo function of the enzyme, new findings on the physiological role of D-amino acid oxidase point to a detoxifying function of the enzyme in metabolizing exogenous D-amino acids in animals. A novel role in modulating the level of D-serine in brain has also been proposed for the enzyme. At the molecular level, site-directed mutagenesis studies on the pig kidney D-amino acid oxidase and, more recently, on the enzyme from the yeast Rhodotorula gracilis indicated that the few conserved residues of the active site do not play a role in acid-base catalysis but rather are involved in substrate interactions. The three-dimensional structure of the enzyme was recently determined from two different sources: at 2.5-3.0 A resolution for DAAO from pig kidney and at 1.2-1.8 A resolution for R. gracilis. The active site can be clearly depicted: the striking absence of essential residues acting in acid-base catalysis and the mode of substrate orientation into the active site, taken together with the results of free-energy correlation studies, clearly support a hydrid transfer type of mechanism in which the orbital steering between the substrate and the isoalloxazine atoms plays a crucial role during catalysis. PMID:11130179

  2. Uptake and utilization characteristics of Prorocentrum donghaiense, Phaeoecystis globosa, Karenia mikimotoi and Skeletonema costatum for dissolved free amino acids%海洋微藻对游离氨基酸的利用特性研究

    Institute of Scientific and Technical Information of China (English)

    徐宁; 刘静雅; 赖海燕; 胡章喜; 段舜山

    2013-01-01

    The growth dynamics, photosynthetic characteristics and uptake kinetics of three harmful algae, Prorocentrum donghaiense, Phaeoecystis globosa, Karenia mikimotoi and a common phytoplankton species Skeletonema costatum were studied in the laboratory. The four algae were isolated or collected from the coastal waters of China, with alanine, glycine, glutamate and aspartate used as its sole nitrogen source, respectively. Dissolved inorganic nitrogen nitrate and ammonium were used as controls. The results showed that P. donghaiense and P. globosa were able to utilize multiple free amino acids, while K. mikimotoi and S. costatum could not grow with amino acids as the sole nitrogen sources under axenic conditions. The specific growth rates of P. donghaiense and P. globosa were the highest when alanine acted as the sole nitrogen source, followed by glutamate, aspartate and glycine. Fv/Fm values of amino acid treatments declined slightly and slowly in the later growth stage, but still higher than inorganic nitrogen treatments. The maximum uptake rates of P. donghaiense and P. globosa for alanine were 3.32 and 0.41 pmol· cell-1· h-1 .respectively, and the half saturation constants were 6. 99 and 20. 54 pmol · L-1 , respectively. Consequently, the capability of uptake and utilization for DFAAs were significantly different among marine microalgae. In the coastal waters with increasing organic pollution, some harmful phytoplankton species equipped with broader nitrogen niche, such as P. donghaiense and P. globosa may enhance their competition potential, and even form red tides under suitable environmental conditions.%分别以4种游离氨基酸——丙氨酸、甘氨酸、谷氨酸和天冬氨酸为唯一氮源,采用实验室一次性培养的方法,研究典型赤潮藻——东海原甲藻(Prorocentrum donghaiense)、球形棕囊藻(Phaeoecystis globosa)和米氏凯伦藻(Karenia mikimotoi)及常见种类中肋骨条藻(Skeletonema costatum)的生长特性、光合特

  3. Amino acid survival in large cometary impacts

    Science.gov (United States)

    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.

  4. Transport of amino acids and GABA analogues via the human proton-coupled amino acid transporter, hPAT1

    DEFF Research Database (Denmark)

    Larsen, Mie; Larsen, Birger Brodin; Frølund, Bente; Nielsen, Carsten Uhd

    The objective of this study was to investigate transepithelial amino acid transport as a function of Caco-2 cell culture time. Furthermore, the objective was to investigate apical uptake characteristics of hPAT1-mediated transport under various experimental conditions. Apical amino acid uptake and...... transport studies were conducted in Caco-2 monolayers cultured for 4-28 days. Transepithelial transport of the prototypic hPAT1 (SLC36A1) substrates l-proline and glycine were maximal after 21-28 days in culture. Based on proton-dependency and substrate kinetics the major apical uptake and transport of Gly...... and Pro in Caco-2 cell monolayers is hPAT1-mediated. The apical uptake of Pro is decreased at apical hyperosmolarity conditions. Furthermore we identified the two GABA-analogues, muscimol and THPO as novel hPAT1 substrates. THPO had an affinity for hPAT1 of 11.3mM, whereas muscimol had one of the...

  5. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

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

    Directory of Open Access Journals (Sweden)

    Zimmermann Karel

    2010-01-01

    Full Text Available Abstract 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.

  7. Economic aspects of amino acids production.

    Science.gov (United States)

    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

  8. Postprandial fate of amino acids: adaptation to molecular forms

    NARCIS (Netherlands)

    Nolles, J.A.

    2006-01-01

    During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however, inco

  9. Amino acid absorption and homeostasis in mice lacking the intestinal peptide transporter PEPT1.

    Science.gov (United States)

    Nässl, Anna-Maria; Rubio-Aliaga, Isabel; Fenselau, Henning; Marth, Mena Katharina; Kottra, Gabor; Daniel, Hannelore

    2011-07-01

    The intestinal peptide transporter PEPT1 mediates the uptake of di- and tripeptides derived from dietary protein breakdown into epithelial cells. Whereas the transporter appears to be essential to compensate for the reduced amino acid delivery in patients with mutations in amino acid transporter genes, such as in cystinuria or Hartnup disease, its physiological role in overall amino acid absorption is still not known. To assess the quantitative importance of PEPT1 in overall amino acid absorption and metabolism, PEPT1-deficient mice were studied by using brush border membrane vesicles, everted gut sacs, and Ussing chambers, as well as by transcriptome and proteome analysis of intestinal tissue samples. Neither gene expression nor proteome profiling nor functional analysis revealed evidence for any compensatory changes in the levels and/or function of transporters for free amino acids in the intestine. However, most plasma amino acid levels were increased in Pept1(-/-) compared with Pept1(+/+) animals, suggesting that amino acid handling is altered. Plasma appearance rates of (15)N-labeled amino acids determined after intragastric administration of a low dose of protein remained unchanged, whereas administration of a large protein load via gavage revealed marked differences in plasma appearance of selected amino acids. PEPT1 seems, therefore, important for overall amino acid absorption only after high dietary protein intake when amino acid transport processes are saturated and PEPT1 can provide additional absorption capacity. Since renal amino acid excretion remained unchanged, elevated basal concentrations of plasma amino acids in PEPT1-deficient animals seem to arise mainly from alterations in hepatic amino acid metabolism. PMID:21350187

  10. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B;

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2), on......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...

  11. Cometary Amino Acids from the STARDUST Mission

    Science.gov (United States)

    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.

  12. Biosynthesis of the Aromatic Amino Acids.

    Science.gov (United States)

    Pittard, James; Yang, Ji

    2008-09-01

    This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed. Two regulatory proteins, TrpR (108 amino acids) and TyrR (513 amino acids), play a major role in transcriptional regulation. The TrpR protein functions only as a dimer which, in the presence of tryptophan, represses the expression of trp operon plus four other genes (the TrpR regulon). The TyrR protein, which can function both as a dimer and as a hexamer, regulates the expression of nine genes constituting the TyrR regulon. TyrR can bind each of the three aromatic amino acids and ATP and under their influence can act as a repressor or activator of gene expression. The various domains of this protein involved in binding the aromatic amino acids and ATP, recognizing DNA binding sites, interacting with the alpha subunit of RNA polymerase, and changing from a monomer to a dimer or a hexamer are all described. There is also an analysis of the various strategies which allow TyrR in conjunction with particular amino acids to differentially affect the expression of individual genes of the TyrR regulon. PMID:26443741

  13. Mutagenic effect of incorporated tritium amino acids

    International Nuclear Information System (INIS)

    Genetic effect of tritium labelled amino acids was studied. The experiments were carried out on white mongreal rats, genetic effects were evaluated by dominant lethal mutation frequency in male germ cells. It was shown that administration of tritium amino acids results in genetic violations in male germ cells manifested in progeny death. Assessment of integral temporal indices of induced post implantation embryos death showed that 3H-lysine effect exceeds tritium oxide effect by 1.5-2 fold in case of equal absorbed doses. The obtained results are used in alculation of radiation hygienic standards for biogenic tritium compounds. 4 refs.; 1 tab

  14. Postprandial fate of amino acids: adaptation to molecular forms

    OpenAIRE

    Nolles, J.A.

    2006-01-01

    During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however, incorporated into body proteins part of these amino acids are oxidized, and can, thus, no longer be utilized to support protein metabolism in the body. The objective of this thesis was to increase the ...

  15. Amino acid derived 1,4-dialkyl substituted imidazolones

    DEFF Research Database (Denmark)

    Diness, Frederik; Meldal, Morten Peter

    2010-01-01

    A general method for synthesis of 1,4-substituted imidazolones from amino acids on solid support or in solution has been developed. Amino acid derived 3-Boc-(1,3)-oxazinane (Box) protected amino aldehyde building blocks were coupled through urea bonds to the amino terminal of dipeptides or amino...

  16. Polymerization of amino acids containing nucleotide bases

    Science.gov (United States)

    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.

  17. Estimate of Amino Acid Balance in Nutrition

    Institute of Scientific and Technical Information of China (English)

    SunWenzhi

    1995-01-01

    A new chemical index-imbalance degree(IBD),was proposed on the basis of cluster analysis in multivariate statistical analysis to estimate the extent of amino acid balance in protein.The range of IBD is between 0 and 1,successively corresponding to complete baance and entire imbalance for the amino acid profile of a sample.The amino acid increment model of IBD belongs to an asymmetrical maximum-type,and there is a high correlation between IBD and coefficient of variation(CV),The nutritional Value of individual feed can be ranked and clustered according to its IBD;and by calculating the IBD of amixed sample with two or more feedstuffs,it is possible theoretically to predict whether a synergetic phenomenon exists and when an optimal mutual complement can happen.If the conceptive frame of IBD extended,it can be used to study the balance of plement can happen.If the conceptive frame of IBD extended,it can be used to study the balance of nutrients besides amino acids,and is helpful to realize the automatic distinction and selection in diet formulating.

  18. Dietary Supplements and Sports Performance: Amino Acids

    OpenAIRE

    Williams Melvin

    2005-01-01

    Abstract This is the third in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; metabolites, constituents/extracts, or combinations). The major focus is on efficacy of such dietary supplements to enhance exercise or sport performance.

  19. Amino acid modifications on tRNA

    Institute of Scientific and Technical Information of China (English)

    Jing Yuan; Kelly Sheppard; Dieter S(o)ll

    2008-01-01

    The accurate formation of cognate aminoacyl-transfer RNAs (aa-tRNAs) is essential for the fidelity of translation.Most amino acids are esterified onto their cognate tRNA isoacceptors directly by aa.tRNA synthetases.However,in the case of four amino acids (Gin,Asn,Cys and Sec),aminoacyl-tRNAs are made through indirect pathways in many organisms across all three domains of life.The process begins with the charging ofnoncognate amino acids to tRNAs by a specialized synthetase in the case of Cys-tRNAcys formation or by synthetases with relaxed specificity,such as the non-discriminating glutamyl-tRNA,non-discriminating aspartyl-tRNA and seryl-tRNA synthetases.The resulting misacylated tRNAs are then converted to cognate pairs through transformation of the amino acids on the tRNA,which is catalyzed by a group of tRNA-dependent modifying enzymes,such as tRNA-dependent amidotransferases,Sep-tRNA:Cys-tRNA synthase,O-phosphoseryi-tRNA kinase and Sep-tRNA:Sec-tRNA synthase.The majority of these indirect pathways are widely spread in all domains of life and thought to be part of the evolutionary process.

  20. Conformational Interconversions of Amino Acid Derivatives

    Czech Academy of Sciences Publication Activity Database

    Kaminský, Jakub; Jensen, F.

    2016-01-01

    Roč. 12, č. 2 (2016), s. 694-705. ISSN 1549-9618 R&D Projects: GA ČR GA13-03978S; GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : amino acids * force fields * transition states Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.498, year: 2014

  1. Amino acid quality indices of the leaves of Clerodendrum volubile

    Directory of Open Access Journals (Sweden)

    Ochuko Lucky Erukainure

    2016-04-01

    Full Text Available Objective: To evaluate the amino acid profile and quality indices of Clerodendrum volubile (C. volubile leaves. Methods: Dried leaves of C. volubile were blended, defatted and subjected to amino acid analysis using the technicon sequential multi-sample amino acid analyzer. The amino acid quality indices which covers for chemical score, essential amino acid index, nutritional index, true digestibility, protein digestibility corrected amino acid score, and digestible indispensable amino acid score were evaluated using standard formulas. Results: Amino acid analysis revealed glutamic acid to have the highest concentration, with cysteine having the least. Aspartic acid had the highest chemical score, this was followed by glycine, histidine and arginine, respectively. The least scores were observed in serine and methionine. Glutamic acid had the highest value for true digestibility and protein digestibility corrected amino acid score, with the least observed in cysteine. Digestible indispensable amino acid score evaluation showed histidine to have the highest value for infants (birth to 6 months, threonine for children (6 months to 3 years, while isoleucine was observed to have the highest value for older children, adolescents and adults. The essential amino acid index value was less than 4, while nutritional index value was less than 0.5. Conclusions: These results indicated the leaves of C. volubile as a potential source of amino acids in the human diet as portrayed by its amino acids profile and qualities.

  2. Choline inhibition of amino acid transport in preimplantation mouse blastocysts

    International Nuclear Information System (INIS)

    Addition of 70 mM choline chloride to Brinster's medium (140 mM Na+) inhibited uptake of ∼ 1 μM [3H]glycine, leucine, lysine and alanine in blastocysts by about 50% each during a five-minute incubation period at 370C, whereas 70 mM LiCl, sodium acetate and NaCl or 140 mM mannitol had no effect. They attribute the apparent linear relationship between Gly transport in blastocysts and the square of the [Na+], observed when choline was substituted for Na+ in Brinster's medium, to concomitant, concentration-dependent enhancement and inhibition of transport by Na+ and choline, respectively. As expected, Gly uptake and the [Na+] were linearly related up to 116 mM Na+, when Na+ was replaced with Li+. The rates of Na+-independent Gly and Ala uptake were + or choline replaced Na+. Therefore, neither Li+ nor choline appears to substitute for Na+ in supporting Na+-dependent transport in blastocysts. Na+-independent Leu uptake was 20 times faster than Gly or Ala uptake and appeared to be inhibited by choline in blastocysts since it was about 37% slower when choline instead of Li+ was substituted for Na+. In contrast to blastocysts, choline had no effect on amino acid transport in cleavage-stage mouse embryos. The unexpected sensitivity of transport to choline in blastocysts underscores the importance of testing the effects of this substance when it is used to replace Na+ in new transport studies

  3. Roles of phytochemicals in amino acid nutrition.

    Science.gov (United States)

    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. PMID:21196382

  4. Regulation of amino acid transport in isolated rat hepatocytes during development

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, S.; Spagnuolo, S.; Dini, L.; Devirgiliis, L.C.

    1987-01-01

    The effect of amino acid depletion or supplementation and the effect of glucagon and insulin on the amino acid transport mediated by system A were investigated by determining the uptake of either 2-amino (1-/sup 14/C)isobutyric acid (AIB) or N-methyl 2-amino (1-/sup 14/C)isobutyric acid (MeAIB) in rat hepatocytes, freshly isolated at different stages of pre- and postnatal development. The data obtained show that the Na/sup +/ -dependent uptake was higher at the earliest developmental stages, and steadily decreased until the adult level. The hormones increased AIB and MeAIB uptake enhancing the V/sub max/, while the K/sub m/ was unchanged. This effect was evident in cells from adult and 18-20-day-old fetuses, while no response was present before the 18th day of fetal life and in the prenatal period. Actinomycin D or cycloheximide abolished this hormone-dependent increase. A decrease in AIB and MeAIB transport after incubation in an amino acid-rich medium was demonstrated at all ages tested, but was particularly evident in the prenatal life. The increase in the activity of the system following amino acid starvation was shown to be mostly dependent from de novo protein synthesis in the fetal life; on the contrary in the adult the increase appeared to be more linked to the release from transinhibition of the transport.

  5. gamma-Glutamyl amino acids. Transport and conversion to 5-oxoproline in the kidney

    International Nuclear Information System (INIS)

    Transport of gamma-glutamyl amino acids, a step in the proposed glutathione-gamma-glutamyl transpeptidase-mediated amino acid transport pathway, was examined in mouse kidney. The transport of gamma-glutamyl amino acids was demonstrated in vitro in studies on kidney slices. Transport was followed by measuring uptake of 35S after incubation of the slices in media containing gamma-glutamyl methionine [35S]sulfone. The experimental complication associated with extracellular conversion of the gamma-glutamyl amino acid to amino acid and uptake of the latter by slices was overcome by using 5-oxoproline formation (catalyzed by intracellular gamma-glutamyl-cyclotransferase) as an indicator of gamma-glutamyl amino acid transport. This method was also successfully applied to studies on transport of gamma-glutamyl amino acids in vivo. Transport of gamma-glutamyl amino acids in vitro and in vivo is inhibited by several inhibitors of gamma-glutamyl transpeptidase and also by high extracellular levels of glutathione. This seems to explain urinary excretion of gamma-glutamylcystine by humans with gamma-glutamyl transpeptidase deficiency and by mice treated with inhibitors of this enzyme. Mice depleted of glutathione by treatment with buthionine sulfoximine (which inhibits glutathione synthesis) or by treatment with 2,6-dimethyl-2,5-heptadiene-4-one (which effectively interacts with tissue glutathione) exhibited significantly less transport of gamma-glutamyl amino acids than did untreated controls. The findings suggest that intracellular glutathione functions in transport of gamma-glutamyl amino acids. Evidence was also obtained for transport of gamma-glutamyl gamma-glutamylphenylalanine into kidney slices

  6. Yeast biodiversity in Slovenian wine regions: Case amino acids in spontaneous and induced fermentations of Malvasia

    Directory of Open Access Journals (Sweden)

    Raspor Peter I.

    2009-01-01

    Full Text Available Microbial biodiversity can also be reflected in final product composition. The work described in this paper investigates the differences in the amino acid composition of 14 Malvasia musts/wines fermented with local and commercial starter yeasts, comparing all to the spontaneous fermentations of must of the same origin. We tried to ascertain whether the changes were dependent upon different initiations of fermentations. A comparative study of free and total amino acid evolution was prepared. The total concentration of 15 amino acids studied was 1975 mg/l, and the concentration of fraee amino acids was 1061 mg/l. Spontaneous and induced fermentations showed different fermentation rates. Three to nine days were needed to reduce sugar by 50%. Although the proline is regarded as non-assailable amino acid, decreases in concentration were observed. Lysine was the only amino acid where the concentration increased. The minimal uptakes of amino acids occurred during spontaneous fermentations, whereas the maximal uptakes were observed in the fermentations inoculated with local starters.

  7. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Science.gov (United States)

    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,...

  8. Sulfur amino acid metabolism in the whole body and mammary gland of the lactating Saanen goat

    International Nuclear Information System (INIS)

    Five multiparous Saanen goats in late lactation were infused with 35S-cysteine into the mammary gland via the external pudic artery. A further 2 goats were infused with 35S-methionine via the same artery and later with 35S-methionine into the jugular vein. Total uptake of cysteine from the arterial blood supply by the mammary gland was approximately 6% of the 35S-cysteine flux past the gland, whereas uptake of methionine was 30-40%. Total mammary uptake of cysteine was also lower than that of methionine when expressed as a percentage of whole body utilisation (6.5 and 14%, respectively). The uptake from the blood did not account for output in the milk for either cysteine or methionine. Both amino acids were highly conserved by the gland as shown by little release of any degraded constitutive protein amino acids and no evidence of oxidation products of either cysteine or methionine being released into the blood. Comparison of 35S activity in the milk from the infused and non-infused sides of the gland showed up to 10% trans-sulfuration of methionine to cysteine within the gland, none of which was exported in the venous drainage. Total ATP production by one side of the gland was 12.1 mol/day or 13 mmol/min.kg mammary tissue, of which 15% was required for gland protein synthesis. The experimental measurements from both the cysteine and methionine infusions were used to solve a model of gland amino acid uptake and partitioning. Modelling radioactivity of both amino acids in the blood, intracellular free pool, and milk protein suggested that a single intracellular pool cannot be the only source of amino acid for protein synthesis. The model also provides support for the hypothesis that a significant proportion of the uptake of at least some amino acids by the mammary gland is from intracellular hydrolysis of extracellularly derived peptides. Copyright (2001) CSIRO Australia

  9. Rotational Study of Natural Amino Acid Glutamine

    Science.gov (United States)

    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.

  10. Amino Acid Decarboxylase Activity of Some Lactic Acid Bacteria

    OpenAIRE

    Pelin ERTÜRKMEN; Turhan, İlkay; Öner, Zübeyde

    2015-01-01

    Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of lactic acid bacteria as a starter culture in fermented products. In this study, decarboxylase activities of 161 lactic acid bacteria (LAB) strain...

  11. Branched-chain amino acids for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Koretz, R L; Kjaergard, L L;

    2003-01-01

    Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy....

  12. Amino acid protein composition of grain of common wheat mutants

    International Nuclear Information System (INIS)

    The quantitative ratio of some amino acids changes in the grain of soft wheat morphological mutants with a high protein content. The soft wheat mutants developed, valuable for breeding, surpass the initial varieties in total protein content and the content of some amino acids in grain. The relative content of some amino acids in protein varies, and the stable sum of irreplaceable amino acids in it is retained

  13. Functional analysis of sequences adjacent to dapE of Corynebacterium glutamicum reveals the presence of aroP, which encodes the aromatic amino acid transporter.

    OpenAIRE

    Wehrmann, A; Morakkabati, S; Krämer, R; Sahm, H; Eggeling, L

    1995-01-01

    An initially nonclonable DNA locus close to a gene of L-lysine biosynthesis in Corynebacterium glutamicum was analyzed in detail. Its stepwise cloning and its functional identification by monitoring the amino acid uptakes of defined mutants, together with mechanistic studies, identified the corresponding structure as aroP, the general aromatic amino acid uptake system.

  14. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    DEFF Research Database (Denmark)

    Lomstein, Bente Aagaard; Jørgensen, Bo Barker; Schubert, Carsten J.;

    2006-01-01

    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 Concepcion. The contribution of amino acids to total organic...

  15. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Science.gov (United States)

    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....

  16. Amino acid analysis and group function of camel insulin

    Directory of Open Access Journals (Sweden)

    A. E. A. Baragob,

    2011-02-01

    Full Text Available In the current study, the claimed amino analysis and groups fraction of Sudanese camels’ insulin was obtained by hydrolysis using amino acid analyzer. The result obtained indicated the presence of all amino acids except cystine and tryptophan which were not detected by this method due to destruction during acid hydrolysis.

  17. Amino acid analysis and group function of camel insulin

    OpenAIRE

    A. E. A. Baragob,; O. Y. Mohammed,; A. F. Mustafa,; S. M. E. Khojali; H. A. Samia

    2011-01-01

    In the current study, the claimed amino analysis and groups fraction of Sudanese camels’ insulin was obtained by hydrolysis using amino acid analyzer. The result obtained indicated the presence of all amino acids except cystine and tryptophan which were not detected by this method due to destruction during acid hydrolysis.

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

    Science.gov (United States)

    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...

  19. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  20. Metabolism of amino acid amides in Pseudomonas putida ATCC 12633

    NARCIS (Netherlands)

    Hermes, H.F.M.; Croes, L.M.; Peeters, W.P.H.; Peters, P.J.H.; Dijkhuizen, L.

    1993-01-01

    The metabolism of the natural amino acid L-valine, the unnatural amino acids D-valine, and D-, L-phenylglycine (D-, L-PG), and the unnatural amino acid amides D-, L-phenylglycine amide (D, L-PG-NH2) and L-valine amide (L-Val-NH2) was studied in Pseudomonas putida ATCC 12633. The organism possessed c

  1. The Role of Microbial Amino Acid Metabolism in Host Metabolism

    Directory of Open Access Journals (Sweden)

    Evelien P. J. G. Neis

    2015-04-01

    Full Text Available Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous proteins. In turn, gut bacteria also provide amino acids to the host. This could have significant implications in the context of insulin resistance and type 2 diabetes mellitus, conditions associated with elevated systemic concentrations of certain amino acids, in particular the aromatic and branched-chain amino acids. Moreover, several amino acids released by gut bacteria can serve as precursors for the synthesis of short-chain fatty acids, which also play a role in the development of obesity. In this review, we aim to compile the available evidence on the contribution of microbial amino acids to host amino acid homeostasis, and to assess the role of the gut microbiota as a determinant of amino acid and short-chain fatty acid perturbations in human obesity and type 2 diabetes mellitus.

  2. Protein and Amino Acid Requirements during Pregnancy.

    Science.gov (United States)

    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. PMID:27422521

  3. Incretin effect after oral amino Acid ingestion in humans

    DEFF Research Database (Denmark)

    Lindgren, Ola; Pacini, Giovanni; Tura, Andrea;

    2015-01-01

    also present after amino acid ingestion is not known. OBJECTIVE: The objective of the study was to explore insulin secretion and incretin hormones after oral and iv amino acid administration at matched total amino acid concentrations in healthy subjects. DESIGN: An amino acid mixture (Vaminolac) was...... administered orally or iv at a rate resulting in matching total amino acid concentrations to 12 male volunteers with age 22.5 ± 1.4 years and a body mass index 22.4 ± 1.4 kg/m(2), who had no history of diabetes. MAIN OUTCOME MEASURES: Main outcome measures were area under the 120-minute curve for insulin, C...... after oral than after iv amino acid challenges (P = .006), whereas there was no significant difference in the glucagon response. Intact and total GIP rose after oral but not after iv amino acid administration, whereas intact and total GLP-1 levels did not change significantly in either test. CONCLUSION...

  4. Comparative Amino Acid Sequences of Dengue Viruses

    OpenAIRE

    Haishi, Shozo; TANAKA Mariko; Igarashi, Akira

    1990-01-01

    Amino acid (AA) sequences of 4 serotype of dengue viruses deduced from their nucleotide (nt) sequences of genomic RNA were analyzed for each genome segment and each stretch of 10 AA residues. Precursor of membrane protein (pM), and 4 nonstructural proteins (NS1, NS3, NS4B, NS5) were highly conserved, while another nonstructural protein (NS2A) was least conserved among 5 strains of dengue viruses. When homology was compared among heterotypic viruses, type 1 and type 3 dengue viruses showed clo...

  5. D-Amino Acids Trigger Biofilm Disassembly

    OpenAIRE

    Kolodkin-Gal, Illana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard

    2010-01-01

    Bacteria form communities known as biofilms, which disassemble over time. Here we found that prior to biofilm disassembly Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofi...

  6. Large neutral amino acids in daily practice

    DEFF Research Database (Denmark)

    Ahring, Kirsten Kiær

    2010-01-01

    At the Kennedy Centre for Phenylketonuria, Denmark, large neutral amino acids (LNAAs) are being used to treat adult and adolescent patients who are nonadherent to dietary treatment for phenylketonuria (PKU). At the start of treatment, a patient must undergo dietary analysis and regular blood...... maintaining this level of protein intake). Patients are therefore able to follow a more "normal" diet than those adhering to a PKU diet with AA supplementation (in which only 20% of the daily protein requirement is provided from the diet and 80% from AA supplementation). LNAAs have also been used to treat...

  7. Photoinduced dynamics in protonated aromatic amino acid

    CERN Document Server

    Grégoire, Gilles; Barat, Michel; Fayeton, Jacqueline; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2008-01-01

    UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

  8. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Michael D Barton

    Full Text Available 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

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

    Science.gov (United States)

    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.

  11. Regulatory signals for intestinal amino acid transporters and peptidases

    International Nuclear Information System (INIS)

    Dietary protein ultimately regulates many processes involved in protein digestion, but it is often unclear whether proteins themselves, peptides, or amino acids (AAs) are the proximate regulatory signal. Hence the authors compared several processes involved in protein digestion in mice adapted to one of three rations, identical except for containing 54% of either casein, a partial hydrolysate of casein, or a free AA mixture simulating a complete hydrolysate of casein. The authors measured brush-border uptakes of seven AAs that variously serve as substrates for four AA transporters, and brush-border and cytosolic activities of four peptidases. The three rations yielded essentially the same AA uptake rates. Peptidase activities tended to be lower on the AA ration than on the protein ration. In other studies, all three rations yielded the same rates of brush-border peptide uptake; protein is only modestly more effective than AAs at inducing synthesis of pancreatic proteases; and, depending on the animal species, protein is either much less or much more effective than AAs at stimulating release of cholecystokinin and hence of pancreatic enzymes. Thus the regulators of each process involved in protein digestion are not necessarily that process's substrate

  12. Amino Acids as a Source of Organic Nitrogen in Antarctic Endolithic Microbial Communities

    Science.gov (United States)

    McDonald, G. D.; Sun, H. J.

    2002-12-01

    In the Antarctic Dry Valleys, cryptoendolithic microbial communities occur within porous sandstone rocks. Current understanding of the mechanisms of physiological adaptation of these communities to the harsh Antarctic environment is limited, because traditional methods of studying microbial physiology are very difficult to apply to organisms with extremely low levels of metabolic activity. In order to fully understand carbon and nitrogen cycling and nutrient uptake in cryptoendolithic communities, and the metabolic costs that the organisms incur in order to survive, it is necessary to employ molecular geochemical techniques such as amino acid analysis in addition to physiological methods. Low-molecular-weight biomolecules such as amino acids can be used as tracers of carbon and nitrogen uptake and loss by microbial communities living in solid-state matrices such as rock or sediment. We have measured the concentrations and D/L ratios for several amino acids as a function of depth in a large sandstone boulder. Concentrations of both free and bound amino acids decrease by more than two orders of magnitude from the surface to the visible base of the community (approximately 1.2 cm depth), while the D/L ratios of the amino acids increase from near zero to 0.2 or greater over the same depth interval. We interpret these data as an indication that one or more community members are selectively scavenging L-amino acids as the amino acids are transported through the rock by intermittently percolating meltwater. This is consistent with the known preference of lichens for amino acids as nitrogen sources rather than inorganic nitrogen under conditions of nutrient limitation. It is not yet clear whether there is also a contribution to amino acid uptake from heterotropic bacteria associated with the cryptoendolithic community. The increase in D/L ratios with depth observed in the rock is too great to be attributable solely to the natural occurrence of D-amino acids in bacteria

  13. Docosahexaenoic acid affects arachidonic acid uptake in megakaryocytes

    Energy Technology Data Exchange (ETDEWEB)

    Schick, P.K.; Webster, P.

    1987-05-01

    Dietary omega 3 fatty acids are thought to prevent atherosclerosis, possibly by modifying platelet (PT) function and arachidonic acid (20:4) metabolism. The study was designed to determine whether omega 3 fatty acids primarily affect 20:4 metabolism in megakaryocytes (MK), bone marrow precursors of PT, rather than in circulating PT. MK and PT were isolated from guinea pigs and incubated with (/sup 14/C)-20:4 (0.13uM). Docosahexaenoic acid (22:6) is a major omega 3 fatty acid in marine oils. The incubation of MK with 22:6 (0.1, 1.0 uM) resulted in the decrease of incorporation of (/sup 14/C)-20:4 into total MK phospholipids, 16% and 41% respectively. Alpha-linolenic acid (18:3), a major omega 3 fatty acid present in American diets, had no effect on 20:4 uptake in MK. 22:6 primarily affected the uptake of (/sup 14/C)-20:4 into phosphatidylethanolamine (PE) and phosphatidylserine (PS) in MK. In MK, 22:6 (0.1, 1.0 uM) caused a decrease of incorporation of (/sup 14/C)-20:4 into PE, 21% and 55% respectively; a decrease into PS, 16% and 48% respectively; but only a decrease of 4% and 18%, respectively, into phosphatidylcholine; and a decrease of 3% and 21% into phosphatidylinositol 22:6 (3.0 uM) had no effect on the uptake of AA into PT phospholipids. The study shows that 22:6 has a selective effect on AA uptake in MK and that the acylation or transacylation of PE and PS are primarily affected. 22:6 and other marine omega 3 fatty acids appear to primarily affect megakaryocytes which may result in the production of platelets with abnormal content and compartmentalization of AA.

  14. Conformational properties of oxazoline-amino acids

    Science.gov (United States)

    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.

  15. Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response.

    Science.gov (United States)

    Soong, Yean Yean; Lim, Joseph; Sun, Lijuan; Henry, Christiani Jeyakumar

    2015-12-14

    Consumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia. PMID:26420496

  16. Plasmodium falciparum malaria elicits inflammatory responses that dysregulate placental amino acid transport.

    Directory of Open Access Journals (Sweden)

    Philippe Boeuf

    2013-02-01

    Full Text Available Placental malaria (PM can lead to poor neonatal outcomes, including low birthweight due to fetal growth restriction (FGR, especially when associated with local inflammation (intervillositis or IV. The pathogenesis of PM-associated FGR is largely unknown, but in idiopathic FGR, impaired transplacental amino acid transport, especially through the system A group of amino acid transporters, has been implicated. We hypothesized that PM-associated FGR could result from impairment of transplacental amino acid transport triggered by IV. In a cohort of Malawian women and their infants, the expression and activity of system A (measured by Na⁺-dependent ¹⁴C-MeAIB uptake were reduced in PM, especially when associated with IV, compared to uninfected placentas. In an in vitro model of PM with IV, placental cells exposed to monocyte/infected erythrocytes conditioned medium showed decreased system A activity. Amino acid concentrations analyzed by reversed phase ultra performance liquid chromatography in paired maternal and cord plasmas revealed specific alterations of amino acid transport by PM, especially with IV. Overall, our data suggest that the fetoplacental unit responds to PM by altering its placental amino acid transport to maintain adequate fetal growth. However, IV more profoundly compromises placental amino acid transport function, leading to FGR. Our study offers the first pathogenetic explanation for FGR in PM.

  17. A reexamination of amino acids in lunar soil

    Science.gov (United States)

    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.

  18. Turkey-hen amino acid composition of brain and eyes

    International Nuclear Information System (INIS)

    The amino acids composition of the brain and eyes of the mature Turkey-hen (Meleagris gallopavo L.), were determined on dry weight basis. Total essential amino acids ranged from 35.1-36.0 g/100 g as 49.5-49.8% of the total amino acids. The amino acid score showed that lysine ranged from 0.76-0.91 (on whole hen.s egg comparison), 0.85-1.03 (on provisional essential amino acid scoring pattern), and 0.81-0.98 (on suggested requirement of the essential amino acid of a preschool child). The predicted protein efficiency ratio was 1.94-2.41, whilst essential amino acid index range was 1.06-1.08 and the calculated isoelectric point range was 3.97-4.18. The correlation coefficient (rxy) was positively high and significant at r = 0.01 for the total amino acids, amino acid scores (on the whole hen.s egg comparisons made) and the isoelectric point. On the whole, the eyes were better in 12/18 or 66.7% parameters of the amino acids than the brain of Turkey-Hen. (author)

  19. The prebiotic synthesis of amino acids - interstellar vs. atmospheric mechanisms

    Science.gov (United States)

    Meierhenrich, U. J.; Muñoz Caro, G. M.; Schutte, W. A.; Barbier, B.; Arcones Segovia, A.; Rosenbauer, H.; Thiemann, W. H.-P.; Brack, A.

    2002-11-01

    Until very recently, prebiotic amino acids were believed to have been generated in the atmosphere of the early Earth, as successfully simulated by the Urey-Miller experiments. Two independent studies now identified ice photochemistry in the interstellar medium as a possible source of prebiotic amino acids. Ultraviolet irradiation of ice mixtures containing identified interstellar molecules (such as H2O, CO2, CO, CH3OH, and NH3) in the conditions of vacuum and low temperature found in the interstellar medium generated amino acid structures including glycine, alanine, serine, valine, proline, and aspartic acid. After warmup, hydrolysis and derivatization, our team was able to identify 16 amino acids as well as furans and pyrroles. Enantioselective analyses of the amino acids showed racemic mixtures. A prebiotic interstellar origin of amino acid structures is now discussed to be a plausible alternative to the Urey-Miller mechanism.

  20. Absorption of Amino Acids and Peptides in a Child with a Variant of Hartnup Disease and Coexistent Coeliac Disease

    Science.gov (United States)

    Tarlow, M. J.; Seakins, J. W. T.; Lloyd, June K.; Matthews, D. M.; Cheng, B.; Thomas, A. J.

    1972-01-01

    A child with a variant of Hartnup disease and co-existent coeliac disease is described. Oral tolerance tests with L-histidine, L-tyrosine, and glycyl-L-tyrosine, and in vitro uptake studies on a small intestinal biopsy with L-histidine and glycyl-L-histidine, showed impaired absorption of the free amino acids, and showed that absorption of tyrosine and mucosal uptake of histidine was better from the dipeptides than from the free amino acids. This supports the hypothesis that the intestinal mucosa can take up small peptides intact, and that the peptide uptake mechanism is not involved in the intestinal defect of Hartnup disease. PMID:5086513

  1. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    Science.gov (United States)

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  2. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    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.

  4. The Origin of Amino Acids in Lunar Regolith Samples

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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...

  6. Urinary excretion of amino acids during radiotherapy

    International Nuclear Information System (INIS)

    Course observations have helped to determine whether and in how far plasma and urine levels of amino acids and some other metabolites of the protein metabolism are changed by whole-body and partial irradiation. The author attempts to use combinations of these changes (e.g. increased taurine and decreased hydroxyproline levels), combined with blood plasma measurements, as indicators of radiation exposure. At the present state of the art, with deeper knowledge of the interfering influences of tumours or secondary diseases, local irradiation (radiotherapy) is a suitable test model for elaborating combinations of indicators on the basis of which even accidental radiation exposure can be detected and estimated by simple means as early as 24 to 36 h later. (orig.)

  7. A Novel Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Hui; LI Shuo; XU Pen-gFei

    2003-01-01

    @@ β-hydroxy-α-amino acids constitute an important class of compounds as naturally occurring amino acids and as components of many complex natural products possessing a wide range of biological activities. [1] As a consequence of the essential role played by these amino acids in the biological systems and their utility as synthetic building blocks, a number of useful strategies have been devised for their preparation. [2

  8. PHARMACOLOGICAL EFFECTS OF SNAKE VENOM L- AMINO ACID OXIDASES

    OpenAIRE

    Joseph Baby; Rajan Sheeja S; M.V Jeevitha; S.U Ajisha

    2011-01-01

    L-Amino acid oxidases are flavoenzymes which catalyze the stereospecific oxidative deamination of an L-amino acid substrate to a corresponding a-ketoacid with hydrogen peroxide and ammonia production. These enzymes, which are widely distributed in many different organisms, exhibit a marked affinity for hydrophobic amino acids, including phenylalanine, tryptophan, tyrosine, and leucine. Snake venom LAAO induces platelet aggregation and cytotoxicity in various cancer cell lines. The enzyme has ...

  9. Amino acid analysis in biological fluids by GC-MS

    OpenAIRE

    Kaspar, Hannelore

    2009-01-01

    Amino acids are intermediates in cellular metabolism and their quantitative analysis plays an important role in disease diagnostics. A gas chromatography-mass spectrometry (GC-MS) based method was developed for the quantitative analysis of free amino acids as their propyl chloroformate derivatives in biological fluids. Derivatization with propyl chloroformate could be carried out directly in the biological samples without prior protein precipitation or solid-phase extraction of the amino acid...

  10. A new synthetic protocol for coumarin amino acid

    OpenAIRE

    Xinyi Xu; Xiaosong Hu; Jiangyun Wang

    2013-01-01

    The hydrochloride of the racemic amino acid (2-(7-hydroxycoumarin-4-yl)ethyl)glycine, which can serve as a fluorescent probe in proteins, and two halogen derivatives of it, were synthesized by using a new synthetic protocol in five steps. It is less costly and relatively easy to prepare this kind of fluorescent amino acid with the new synthetic method. Furthermore, it can be applied to synthesize other derivatives of the coumarin amino acid with some specific properties.

  11. Reconstructing Amino Acid Interaction Networks by an Ant Colony Approach

    OpenAIRE

    Gaci, Omar; Balev, Stefan

    2009-01-01

    In this paper we introduce the notion of protein interaction network. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. We consider the problem of reconstructing protein's interaction network from its amino acid sequence. We rely on a probability that two amino acids interact as a function of their physico-chemical properties coupled to an ant colony system to solve this problem.

  12. Analysis of amino acids network based on distance matrix

    Science.gov (United States)

    Ali, Tazid; Akhtar, Adil; Gohain, Nisha

    2016-06-01

    In this paper we have constructed a distance matrix of the amino acids. The distance is defined based on the relative evolutionary importance of the base position of the corresponding codons. From this distance matrix a network of the amino acids is obtained. We have argued that this network depicts the evolutionary pattern of the amino acids. To examine the relative importance of the amino acids with respect to this network we have discussed different measures of centrality. We have also investigated the correlation coefficients between different measures of centrality. Further we have explored clustering coefficient as well as degree of distribution.

  13. Design and characterization of auxotrophy-based amino acid biosensors.

    Directory of Open Access Journals (Sweden)

    Felix Bertels

    Full Text Available Efficient and inexpensive methods are required for the high-throughput quantification of amino acids in physiological fluids or microbial cell cultures. Here we develop an array of Escherichia coli biosensors to sensitively quantify eleven different amino acids. By using online databases, genes involved in amino acid biosynthesis were identified that - upon deletion - should render the corresponding mutant auxotrophic for one particular amino acid. This rational design strategy suggested genes involved in the biosynthesis of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan, and tyrosine as potential genetic targets. A detailed phenotypic characterization of the corresponding single-gene deletion mutants indeed confirmed that these strains could neither grow on a minimal medium lacking amino acids nor transform any other proteinogenic amino acid into the focal one. Site-specific integration of the egfp gene into the chromosome of each biosensor decreased the detection limit of the GFP-labeled cells by 30% relative to turbidometric measurements. Finally, using the biosensors to determine the amino acid concentration in the supernatants of two amino acid overproducing E. coli strains (i.e. ΔhisL and ΔtdcC both turbidometrically and via GFP fluorescence emission and comparing the results to conventional HPLC measurements confirmed the utility of the developed biosensor system. Taken together, our study provides not only a genotypically and phenotypically well-characterized set of publicly available amino acid biosensors, but also demonstrates the feasibility of the rational design strategy used.

  14. Amino acids in the cultivation of mammalian cells.

    Science.gov (United States)

    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. PMID:26832172

  15. Synthesis of novel fullerene α-amino acid conjugates

    Institute of Scientific and Technical Information of China (English)

    Jing Zhang; Yan Xia Wang; Feng Kang; Ying Ya Shao; Zong Jie Li; Xin Lin Yang

    2008-01-01

    Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas)and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.

  16. Novel amino acids: synthesis of furoxan and sydnonimine containing amino acids and peptides as potential nitric oxide releasing motifs.

    Science.gov (United States)

    Nortcliffe, Andrew; Botting, Nigel P; O'Hagan, David

    2013-07-28

    The incorporation of furoxan and sydnonimine ring systems into amino acid side chains is demonstrated with the preparation of four novel amino acids which carry these nitric oxide-releasing motifs. N-((4-Nitrophenoxy)carbonyl)-3-phenylsydnonimine 9 and bis(phenylsulfonyl)furoxan 10 are the key intermediates for introducing the heterocycle side chains onto appropriate amine and alcohol functionalities respectively. Furoxan 5 and 7 both displayed NO release based on determination of nitrite production. Orthogonal amino acid protecting group strategies were deployed to demonstrate that the amino acids could be incorporated into peptide frameworks. By way of demonstration the amino acids were placed centrally into several tripeptide motifs. Griess test assays showed that these amino acids released NO in the presence of γ-glutathione (GST). PMID:23753002

  17. The development of orally administrable gemcitabine prodrugs with D-enantiomer amino acids: Enhanced membrane permeability and enzymatic stability

    Science.gov (United States)

    Tsume, Yasuhiro; Incecayir, Tuba; Song, Xueqin; Hilfinger, John M.; Amidon, Gordon L.

    2014-01-01

    Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3–17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2–10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of D-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gem-citabine prodrugs. In general, the 5′-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5′-D-valyl-gemcitabine and 5′-D-phenylalanyl-gem-citabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients. PMID:24361461

  18. The development of orally administrable gemcitabine prodrugs with D-enantiomer amino acids: enhanced membrane permeability and enzymatic stability.

    Science.gov (United States)

    Tsume, Yasuhiro; Incecayir, Tuba; Song, Xueqin; Hilfinger, John M; Amidon, Gordon L

    2014-04-01

    Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3-17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2-10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of d-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gemcitabine prodrugs. In general, the 5'-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5'-D-valyl-gemcitabine and 5'-D-phenylalanyl-gemcitabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients. PMID:24361461

  19. Synthesis, Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

    Institute of Scientific and Technical Information of China (English)

    QIAN Hui-Fen; HUANG Wei; LI Hui-Hui; YAO Cheng

    2006-01-01

    Chiral amino acids and their corresponding amino alcohols bearing camphoric backbone were prepared from D-(+)-camphoric imide and characterized by infrared, elemental analysis, ESI-MS, and NMR measurements. Among them, one intermediate (lS,3R)-3-amino-2,2,3-trimethyl cyclopentane-1-carboxylic acid hydrochloride 3 was structurally elucidated by X-ray diffraction techniques. Versatile intermolecular hydrogen bonding interactions observed in its packing structure result in a two-dimensional framework.

  20. Bolus ingestion of individual branched-chain amino acids alters plasma amino acid profiles in young healthy men

    OpenAIRE

    Matsumoto, Takuya; Nakamura, Koichi; Matsumoto, Hideki; Sakai, Ryosei; Kuwahara, Tomomi; Kadota, Yoshihiro; Kitaura, Yasuyuki; SATO, JUICHI; Shimomura, Yoshiharu

    2014-01-01

    Physiological conditions in humans affect plasma amino acid profiles that might have potential for medical use. Because the branched-chain amino acids (BCAAs) leucine, isoleucine and valine are used as medicines and supplements, we investigated the acute effects of individual BCAAs (10–90 mg/kg body weight) or mixed BCAAs ingested as a bolus on plasma amino acid profiles in young healthy men. Plasma leucine levels rapidly increased and peaked around 30 min after leucine ingestion. Concentrati...

  1. Synthesis and evaluation of 2-amino-5-(4-[18F]fluorophenyl)pent-4-ynoic acid ([18F]FPhPA): A novel 18F-labeled amino acid for oncologic PET imaging

    International Nuclear Information System (INIS)

    Introduction: 18 F-labeled amino acids are important PET radiotracers for molecular imaging of cancer. This study describes synthesis and radiopharmacological evaluation of 2-amino-5-(4-[18 F]fluorophenyl)pent-4-ynoic acid ([18 F]FPhPA) as a novel amino acid radiotracer for oncologic imaging. Methods: 18 F]FPhPA was prepared using Pd-mediated SONOGASHIRA cross-coupling reaction between 4-[18 F]fluoroiodobenzene ([18 F]FIB) and propargylglycine. The radiopharmacological profile of [18 F]FPhPA was evaluated in comparison with O-(2-[18 F]fluoroethyl)-L-tyrosine ([18 F]FET) using the murine breast cancer cell line EMT6 involving cellular uptake studies, radiotracer uptake competitive inhibition experiments and small animal PET imaging. Results: 18 F]FPhPA was prepared in 42 ± 10% decay-corrected radiochemical yield with high radiochemical purity >95% after semi-preparative HPLC purification. Cellular uptake of L-[18 F]FPhPA reached a maximum of 58 ± 14 % radioactivity/mg protein at 90 min. Lower uptake was observed for racemic and D-[18 F]FPhPA. Radiotracer uptake inhibition studies by synthetic and naturally occurring amino acids suggested that Na+-dependent system ASC, especially ASCT2, and Na+-independent system L are important amino acid transporters for [18 F]FPhPA uptake into EMT6 cells. Small animal PET studies demonstrated similar high tumor uptake of [18 F]FPhPA in EMT6 tumor-bearing mice compared to [18 F]FET reaching a maximum standardized uptake value (SUV) of 1.35 after 60 min p.i.. Muscle uptake of [18 F]FPhPA was higher (SUV30min = 0.65) compared to [18 F]FET (SUV30min = 0.40), whereas [18 F]FPhPA showed a more rapid uptake and clearance from the brain compared to [18 F]FET. Conclusion: L-[18 F]FPhPA is the first 18 F-labeled amino acid prepared through Pd-mediated cross-coupling reaction. Advances in Knowledge and Implications for patient Care: L-[18 F]FPhPA displayed promising properties as a novel amino acid radiotracer for molecular imaging of

  2. Preferential Treatment: Interaction Between Amino Acids and Minerals

    Science.gov (United States)

    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.

  3. Labelling of some amino acids with radioiodine

    International Nuclear Information System (INIS)

    Some radioiodine labelled compounds which have application in nuclear medicine have been prepared. Two common techniques were employed. A comparative study on the radioiodination of the amino acids, L - tyrosine, L - a - methyl tyrosine and L-tyrosine methyl ester has been carried out by the electrophilic radioiodination technique. The blood flow reagent, antipyrine, also has been prepared by this technique using chloramine - T, iodogen and H2 O2 as oxidizing agents to generate electrophilic iodine. Radio chromatograms revealed side product impurities at long reaction times and high oxidizing agent concentrations. Comparison between the different oxidizing agents was done. Optimization of the radioiodination conditions, such as Ph of the medium, reaction time, oxidizing agent and substrate concentrations and carrier KI concentration was performed resulting in high radiochemical yields of 97% L - 3 -(131) iodotyrosine, 95% L -3-(131) iodo-a-methyl tyrosine, 88% L-3-(131) iodotyrosine methyl ester and 96% 4-(131) iodoantipyrine within short reaction times at room temperature when chloramine - T was used as oxidizing agent. Purification by high pressure liquid chromatography resulted in high radiochemically pure products suitable for medical application. Radioiodinated 3- iodotyrosine and 4- iodophenyl alanine have been prepared by the isotopic exchange technique using cuprous chloride as catalyst for the exchange reaction. The effect of solvents and the different parameters affecting the labelling yield were investigated to optimize the conditions for labelling of these compounds. Kinetic study indicated a second order reaction with an activation energy of 9.6 and 12.20 Kcal/mole for 3- iodotyrosine and 4-iodophenyl alanine respectively. Reducing agents were added to the Cu CI catalyzed reactions to improve the yield and decrease side products formation. Applying the results obtained to the radioiodination of the phenyl fatty acid 15(p-iodophenyl) pentadecanoic acid

  4. Expression cloning of a Na(+)-independent neutral amino acid transporter from rat kidney.

    OpenAIRE

    Tate, S S; Yan, N; Udenfriend, S

    1992-01-01

    Uptake of long-chain and aromatic neutral amino acids into cells is known to be catalyzed by the Na(+)-independent system L transporter, which is ubiquitous in animal cells and tissues. We have used a Xenopus oocyte expression system to clone the cDNA of a system L transporter from a rat kidney cDNA library. The 2.3-kilobase cDNA codes for a protein of 683 amino acids. The transporter has four putative membrane-spanning domains and bears no sequence or structural homology to any known animal ...

  5. Analysis of cyclic pyrolysis products formed from amino acid monomer.

    Science.gov (United States)

    Choi, Sung-Seen; Ko, Ji-Eun

    2011-11-18

    Amino acid was mixed with silica and tetramethylammonium hydroxide (TMAH) to favor pyrolysis of amino acid monomer. The pyrolysis products formed from amino acid monomer were using GC/MS and GC. 20 amino acids of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine were analyzed. The pyrolysis products were divided into cyclic and non-cyclic products. Among the 20 amino acids, arginine, asparagine, glutamic acid, glutamine, histidine, lysine, and phenylalanine generated cyclic pyrolysis products of the monomer. New cyclic pyrolysis products were formed by isolation of amino acid monomers. They commonly had polar side functional groups to 5-, 6-, or 7-membered ring structure. Arginine, asparagine, glutamic acid, glutamine, histidine, and phenylalanine generated only 5- or 6-membered ring products. However, lysine generated both 6- and 7-membered ring compounds. Variations of the relative intensities of the cyclic pyrolysis products with the pyrolysis temperature and amino acid concentration were also investigated. PMID:21993510

  6. Polymerization of beta-amino acids in aqueous solution

    Science.gov (United States)

    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.

  7. Evaluation of 111In-labeled macrocyclic chelator-amino acid derivatives for cancer imaging

    International Nuclear Information System (INIS)

    Purpose: We evaluated new 111In-labeled amino acid derivatives, in which the amino acids are conjugated with1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) or 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A). Methods: DOTA-aminoalanine (DOTA-A), DOTA-aminohomoalanine (DOTA-H), DOTA-lysine (DOTA-L), DO2A-alanine (DO2A-A), DO3A-alanine (DO3A-A) and DO3A-homoalanine (DO3A-H) were labeled with 111In. In vitro cell uptake assays were performed usingHep3B (a human hepatoma cell line), CT26 (a mouse colon cancer cell line) and U87MG (a human glioma cell line). In vitro cell uptake inhibition assays were performed using U87MG and 111In-DO3A-H. U87MG bearing xenografted mice were subject to biodistribution, SPECT imaging, autoradiography, and immunohistochemistry studies. Results: Of the amino acid derivatives and cell lines examined, U87MG and 111In-DO3A-H showed highest uptake in vitro. This uptake was blocked by 2-aminobicyclo-[2,2,1] heptane-2-carboxylic acid (BCH) and by tryptophan. 111In-DO3A-HSPECT imaging of U87MG bearing xenografted mice visualized tumors (mean tumor-to-muscle ratio 3.16±0.74). Autoradiography and immunohistochemistry revealed that 111In-DO3A-H uptake matched L-type amino acid transporter 1 expression. Conclusion: Tumor uptake was successfully imaged using 111In-DO3A-H in U87MG bearing xenografted mice. 111In-DO3A-H appears to be useful for imaging tumors expressing L-type amino acid transporter.

  8. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    OpenAIRE

    Claude Daneault; Saïd Barazzouk

    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, th...

  9. Interactive Hangman Teaches Amino Acid Structures and Abbreviations

    Science.gov (United States)

    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…

  10. Nitrogen and amino acid metabolism in dairy cows

    NARCIS (Netherlands)

    Tamminga, S.

    1981-01-01

    For the process of milk production, the dairy cow requires nutrients of which energy supplying nutrients and protein or amino acid supplying nutrients are the most important. Amino acid supplying nutrients have to be absorbed from the small intestine and the research reported in this thesis mainly c

  11. Ant Colony Approach to Predict Amino Acid Interaction Networks

    OpenAIRE

    Gaci, Omar; Balev, Stefan

    2009-01-01

    In this paper we introduce the notion of protein interaction network. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. We consider the problem of reconstructing protein's interaction network from its amino acid sequence. An ant colony approach is used to solve this problem.

  12. Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

    Science.gov (United States)

    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.

  13. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

    1986-08-01

    Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.

  14. Recommended ingestion of indispensable amino acids to young men . A study using stable isotopes, plasmatic amino acids and nitrogen balance

    International Nuclear Information System (INIS)

    It has been previously stated that the minimum physiological recommendations for the indispensable amino acids in health adults, as proposed by FAO/WHO/UNU in 1985, are far too low, except for the methionine. An amino acid stable isotopic kinetic study was conducted to seek further experimental support to this hypothesis. Twenty healthy young men received an l-amino acid based diet, supplying 140 mg N.kg-1.d-1, patterned on egg protein for 1 week, then for 3 weeks either i) a pattern based on current international recommendations (FAO diet, n=7), ii) a the tentative Laboratory of Human Nutrition of the Massachusetts Institute of Technology, new amino acid recommendation pattern (MIT diet, n=7) or iii) again the egg hen pattern (EGG diet, n=6). All subjects were again studied for one final, consecutive week of the egg diet. At the end of the initial week, at the first and third week with the three experimental diets,and after three days following the return of the egg diet, an 8 h primed continuous intravenous infusion with l-13 C-leucine was conducted (3 h, fast, 5 h fed - while subjects received hourly meals supplying the equivalent of 5/12 total daily intake). Estimation of leucine balance were carried out with measurements plasma free amino acids changes. Daily nitrogen balances were obtained through the study. Interpretation of plasma amino acids profile, and changes of leucine kinetics balances, indicated that the FAO diet was not able to maintain amino acids homeostasis whereas the MIT and the egg diets sustained body amino acids equilibrium with a positive amino acid balance. nitrogen balances tended to be more negative with the FAO diet but failed to show statistically significant differences among the three diets. The finding point out that it would be prudent to use the new, tentative recommended amino acid pattern (MIT diet 0 as the minimum physiological amino acid needs of healthy human adults (author)

  15. Comparative distribution study of C labelled amino acids, glucose-analogue and precursor of nucleic acid, as tumor seeking agents

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Kazuhiro; Mori, Hirofumi; Hisada, Kinichi

    1984-08-01

    As tumor-seeking agents, glucose analogues, natural amino acids, synthetic nonmetabolized amino acids, and precursor of nucleic acids, etc., labeled with positron emitter, such as C and YF have been recently investigated. However, there are very few reports concerning comparative study of tumor uptake and tissue distribution of these agents. This preliminary paper describes comparative distribution and whole-body autoradiography of these agents. UC labeled deoxy-2-fluoro-D-glucose (FDG), L-, DL-leucine, 1-aminocyclopentane carboxylic acid (ACPC), -amino isobutyric acid ( -AIB), and thymidine were intravenously injected through tail vein into separate groups of the experimental animals. As the experimental animals, the mice with Ehrlich tumor and the rats with Hepatoma AH109A were used. Within 30 min after injection, FDG had the highest tumor uptake and tumor to tissue ratios, although FDG was inferior to ACPC and thymidine in related to tumor to heart, lung and brain ratios. However, the time course study indicated that tumor uptake of ACPC, -AIB and D-leucine increased with time, whereas those of other agents decreased with time or reached a plateau. Thus, at 120 min after injection, ACPC had the highest tumor uptake and tumor to tissue ratios, although ACPC was inferior to FDG in related to tumor to blood, liver and pancreas ratios. Autoradiogram of ACPC showed very clear tumor image as well as that of FDG. The above data suggest that synthetic nonmetabolized amino acids, such as ACPC may be promising as tumor-seeking agents, when used with a single photon emission computed tomography, while glucose analogue such as FDG, are the best tumor-seeking agent, when used with a positron emission computed tomography. (author).

  16. Electronic coupling through natural amino acids

    International Nuclear Information System (INIS)

    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

  17. Electronic coupling through natural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Berstis, Laura; Beckham, Gregg T., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov; Crowley, Michael F., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov [National Renewable Energy Laboratory, National Bioenergy Center, 15013 Denver West Pkwy, Golden, Colorado 80401 (United States)

    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.

  18. Electronic coupling through natural amino acids

    Science.gov (United States)

    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.

  19. Amino Acid Carbamates As Prodrugs Of Resveratrol.

    Science.gov (United States)

    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

  20. Supernovae, Neutrinos and the Chirality of Amino Acids

    Directory of Open Access Journals (Sweden)

    Toshitaka Kajino

    2011-05-01

    Full Text Available 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.

  1. Supernovae, Neutrinos, and the Chirality of the Amino Acids

    CERN Document Server

    Boyd, R N; Onaka, T

    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 described. 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.

  2. Stardust, Supernovae and the Chirality of the Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Increased brain fatty acid uptake in metabolic syndrome

    DEFF Research Database (Denmark)

    Karmi, Anna; Iozzo, Patricia; Viljanen, Antti;

    2010-01-01

    To test whether brain fatty acid uptake is enhanced in obese subjects with metabolic syndrome (MS) and whether weight reduction modifies it.......To test whether brain fatty acid uptake is enhanced in obese subjects with metabolic syndrome (MS) and whether weight reduction modifies it....

  4. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    Science.gov (United States)

    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

  5. Non-protein amino acids in peptide design

    Indian Academy of Sciences (India)

    S Aravinda; N Shamala; Rituparna S Roy; P Balaram

    2003-10-01

    An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the use -aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and DPro-Xxx segments for nucleating of -hairpin structures. - and -amino acid residues have been used to expand the range of designed polypeptide structures.

  6. Use of fuzzy clustering technique and matrices to classify amino acids and its impact to Chou's pseudo amino acid composition

    OpenAIRE

    Georgiou, D. N.; Karakasidis, T.E.; Nieto, J J; Torres, A.

    2009-01-01

    Use of fuzzy clustering technique and matrices to classify amino acids and its impact to Chou's pseudo amino acid composition correspondence: Corresponding author. Tel.: +302421074163. (Karakasidis, T.E.) (Karakasidis, T.E.) University of Patras, Department of Mathematics - 265 00 Patras--> - GREECE (Georgiou, D.N.) University of Thessaly, Department of Civil Engineering - 383 34 Volos--> - GREECE (Karakas...

  7. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    Science.gov (United States)

    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.

  8. Organometallic and Bioorganometallic Chemistry – Ferrocene Amino Acids

    Directory of Open Access Journals (Sweden)

    Barišić, L.

    2012-01-01

    Full Text Available This article is the second part of a series dealing with organometallic and bioorganometallic chemistry. In the first part of this series a short review on the history and development of these disciplines was given, emphasizing the importance and scope of bioorganometallic chemistry as a new field dealing with conjugates of organometallics and biomolecules (DNA, PNA, amino acids, peptides.... From the variety of biorganometallics, syntheses and properties of simple conjugates of ferrocene with natural amino acids/peptides were elaborated inter alia. This material is the basis for the second part in which ferrocene amino acids are described. The introduction presents nonproteinogenic alicyclic and aromatic amino acids as the models for the title compounds. Naturally occurring amino acids labelled with ferrocene moiety mostly retain properties of the biomolecules included. Contrary to these ω-ferrocenylamino acids, one could imagine specific amino acids with inserted ferrocene core belonging to either homo- or heterodisubstituted type. The central part of this article is devoted to our investigations of the second type - H2N-(CH2m-Fn-(CH2n-COOH. The general rational procedure for synthesis of these compounds and of their N- and/or C-protected derivatives via the azide intermediates N3-CO-(CH2m- Fn-(CH2n-COOMe has been described. In the solid state derivatives of ferrocene amino acids contain intermolecular hydrogen bonds giving dimeric structures, three-dimensional networks or endless helical chains. The solutions of homologues Ac-NH-(CH2m-Fn-(CH2n-COOMe in nonpolar solvents are dominated by open form conformers. Compounds containing 2–3 ferrocene cores connected by amide, imide and oxalamide spacers were prepared by oligomerization of 1'-aminoferrocene-1-carboxylic acid (Fca or by its condensation with the appropriate reagents. Similar to natural amino acids, ferrocene amino acids are water-soluble substances with high melting points

  9. Graphdiyne as a promising material for detecting amino acids

    Science.gov (United States)

    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.

  10. 小白菜硝态氮、氨基酸态氮的吸收动力学差异%The Difference of Uptake Kinetics of Nitrate,Amino acids by Pakchoi(Brassica chinensis)

    Institute of Scientific and Technical Information of China (English)

    王小丽; 杨丹妮; 叶俊; 黄丹枫

    2012-01-01

    Uptake kinetics of NO3--N and Gly-N by pakchoi(Brassica chinensis),also the effect of NO3--N to Gly-N uptake,were studied under hydroponics conditions.The results indicated that uptake kinetics of different nitrogen forms by two pakchoi cultivars('Jinshen' and 'Wuyueman')accorded with Michaelis-Menten equation.The kinetics parameters,maximum uptake rate(Vmax) and the affinity(1/Km) of NO3--N uptake were greater than those of Gly-N uptake,and the kinetics parameters of Gly-N uptake were greater in Jinshen than in Wuyueman.The uptake rate,maximum uptake rate(Vmax) and the affinity(1/Km) of Gly-N uptake were inhibited by the existence of NO3--N,and there were significant decrease of Vmax in Wuyueman,but no significant decrease of Vmax in Jinshen.Significant differences in dry biomass and N accumulation were found in treatments 10 d,the order was NO3--NGly-N.Significant differences were also observed between the two pakchoi cultivars.Dry biomass and N accumulation of 'Jinshen'were higher than that of 'Wuyueman'in treatment Gly-N.The results showed the difference of N uptake between pakchoi cultivars,and Jinshen may prefer to organic nitrogen source than Wuyueman.%采用无菌溶液培养试验,研究了两个小白菜品种(‘金申’与‘五月慢’)对硝态氮(NO3--N)、甘氨酸态氮(Gly-N)吸收的动力学规律,以及NO3--N对Gly-N吸收动力学参数的影响。结果表明,两个小白菜品种对不同氮源的吸收都符合米氏方程,具有主动吸收的特征,Vmax及1/Km值均为NO3-N〉Gly-N,Gly-N吸收的Vmax及1/Km值‘金申’大于‘五月慢’。NO3--N的存在抑制了小白菜Gly-N的吸收速率、Vmax及1/Km值,其中品种‘五月慢’Gly-N吸收的Vmax下降显著,品种‘金申’下降不显著。常规水培10 d后,小白菜干重、氮积累量对NO3--N与Gly-N处理表现显著差异,均为NO3--N〉Gly-N。品种间差异显著,Gly-N处理下‘金申’干重及氮积累量显著大于‘五月慢’。综上,

  11. Amino acid profiles and digestible indispensable amino acid scores of proteins from the prioritized key foods in Bangladesh.

    Science.gov (United States)

    Shaheen, Nazma; Islam, Saiful; Munmun, Sarah; Mohiduzzaman, Md; Longvah, Thingnganing

    2016-12-15

    Concentrations of standard amino acids were determined in the composite samples (representing 30 agro-ecological zones of Bangladesh) of six prioritized key dietary protein sources: Oryza sativa (rice), Triticum aestivum (wheat flour), Lens culinaris (lentils), Pangusius pangusius (pangas), Labeo rohita (rohu) and Oreochromis mossambicus (tilapia). Digestible indispensable amino acid scores (DIAAS) was calculated using published data on amino acids' digestibility to evaluate the protein quality of these foods. Indispensable amino acid (IAA) contents (mg IAA/g protein), found to be highest in pangas (430) and lowest in wheat (336), of all these analyzed foods exceeded the FAO recommended daily allowance (277mg IAA/g protein) and contributed on average 40% to total amino acid contents. Untruncated DIAAS values ranged from 51% (lysine) in wheat to 106% (histidine) in pangas and distinguished pangas, rohu, and tilapia containing 'excellent quality' protein (DIAAS>100%) with potential to complement lower quality protein of cereals, fruits, and vegetables. PMID:27451158

  12. Evaluation of methods to estimate the essential amino acids requirements of fish from the muscle amino acid profile

    Directory of Open Access Journals (Sweden)

    Álvaro José de Almeida Bicudo

    2014-03-01

    Full Text Available Many methods to estimate amino acid requirement based on amino acid profile of fish have been proposed. This study evaluates the methodology proposed by Meyer & Fracalossi (2005 and by Tacon (1989 to estimate amino acids requirement of fish, which do exempt knowledge on previous nutritional requirement of reference amino acid. Data on amino acid requirement of pacu, Piaractus mesopotamicus, were used to validate de accuracy of those methods. Meyer & Fracalossi's and Tacon's methodology estimated the lysine requirement of pacu, respectively, at 13 and 23% above requirement determined using dose-response method. The values estimated by both methods lie within the range of requirements determined for other omnivorous fish species, the Meyer & Fracalossi (2005 method showing better accuracy.

  13. Effect of carbohydrate ingestion on brain exchange of amino acids during sustained exercise in human subjects

    DEFF Research Database (Denmark)

    Blomstrand, E.; Møller, K.; Secher, Niels Henry;

    2005-01-01

    both trials, but returned to the basal level at 180 min of exercise. In both trials, BCAA were taken up by the brain while glutamine was released. CONCLUSION: The present data show that both tryptophan and BCAA are taken up by the brain during prolonged exercise, and we suggest that the cerebral uptake......AIM: This study investigated the effect of prolonged exercise with and without carbohydrate intake on the brain exchange of amino acids, especially focussing on tryptophan and branched-chain amino acids (BCAA). METHODS: Five male subjects exercised for 3 h on a cycle ergometer at 200 +/- 7 W on two...... occasions; either supplemented with a 6% carbohydrate solution or with flavoured water (placebo). Catheters were inserted into the right internal jugular vein and the radial artery of the non-dominant arm. The brain exchange of amino acids during exercise was calculated from the arterial-jugular venous...

  14. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    Directory of Open Access Journals (Sweden)

    Akiyoshi Hoshino

    2009-06-01

    Full Text Available 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.

  15. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-06-01

    Full Text Available 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.

  16. Conformational Interconversions of Amino Acid Derivatives.

    Science.gov (United States)

    Kaminský, Jakub; Jensen, Frank

    2016-02-01

    Exhaustive conformational interconversions including transition structure analyses of N-acetyl-l-glycine-N-methylamide as well as its alanine, serine, and cysteine analogues have been investigated at the MP2/6-31G** level, yielding a total of 142 transition states. Improved estimates of relative energies were obtained by separately extrapolating the Hartree-Fock and MP2 energies to the basis set limit and adding the difference between CCSD(T) and MP2 results with the cc-pVDZ basis set to the extrapolated MP2 results. The performance of eight empirical force fields (AMBER94, AMBER14SB, MM2, MM3, MMFFs, CHARMM22_CMAP, OPLS_2005, and AMOEBAPRO13) in reproducing ab initio energies of transition states was tested. Our results indicate that commonly used class I force fields employing a fixed partial charge model for the electrostatic interaction provide mean errors in the ∼10 kJ/mol range for energies of conformational transition states for amino acid conformers. Modern reparametrized versions, such as CHARMM22_CMAP, and polarizable force fields, such as AMOEBAPRO13, have slightly lower mean errors, but maximal errors are still in the 35 kJ/mol range. There are differences between the force fields in their ability for reproducing conformational transitions classified according to backbone/side-chain or regions in the Ramachandran angles, but the data set is likely too small to draw any general conclusions. Errors in conformational interconversion barriers by ∼10 kJ/mol suggest that the commonly used force field may bias certain types of transitions by several orders of magnitude in rate and thus lead to incorrect dynamics in simulations. It is therefore suggested that information for conformational transition states should be included in parametrizations of new force fields. PMID:26691979

  17. Formation mechanism of coamorphous drug−amino acid mixtures

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Larsen, Flemming Hofmann; Cornett, Claus;

    2015-01-01

    Two coamorphous drug−amino acid systems, indomethacin−tryptophan (Ind−Trp) and furosemide−tryptophan Fur−Trp), were analyzed toward their ease of amorphization and mechanism of coamorphization during ball milling. The two mixtures were compared to the corresponding amorphization of the pure drug...... without amino acid. Powder blends at a 1:1 molar ratio were milled for varying times, and their physicochemical properties were investigated using XRPD, 13C solid state NMR (ssNMR), and DSC. Comilling the drug with the amino acid reduced the milling time required to obtain an amorphous powder from more...... acid being dissolved in the amorphous drug, whereas coamorphous Fur−Trp was formed by the drug being dissolved in the amorphous amino acid....

  18. EFFECT OF TETRACYCLINES ON THE INTRACELLULAR AMINO ACIDS OF MOLDS.

    Science.gov (United States)

    FREEMAN, B A; CIRCO, R

    1963-07-01

    Freeman, Bob A. (University of Chicago, Chicago, Ill.) and Richard Circo. Effect of tetracyclines on the intracellular amino acids of molds. J. Bacteriol. 86:38-44. 1963.-The tetracycline antibiotics were shown to alter the amino acid metabolism of molds whose growth is not markedly affected. Eight molds were grown in the presence of these antiobiotics; four exhibited a general reduction in the concentration of the intracellular amino acids, except for glutamic acid and alanine. In most of these four cultures, the tetracyclines also caused the complete disappearance of arginine, lysine, proline, phenylalanine, and tyrosine from the intracellular amino acid pool. The significance of these observations and the usefulness of the method in the study of the mechanisms of antibiotic action are discussed. PMID:14051820

  19. The origin of amino acids in lunar regolith samples

    Science.gov (United States)

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

    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 14.5-651.1 ppb in 6 M 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: α-aminoisobutyric acid (AIB), D- and L-β-amino-n-butyric acid (β-ABA), DL-α-amino-n-butyric acid, γ-amino-n-butyric acid, β-alanine, and ε-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 β-ABA were present in some samples. We also examined seven samples from Apollo 15, 16, and 17 that had been previously allocated to a non-curation laboratory, as well as two samples of terrestrial dunite from studies of lunar module engine exhaust that had been stored in the same laboratory. The amino acid content of these samples suggested that contamination had occurred during non-curatorial storage. We measured the compound-specific carbon isotopic ratios of glycine, β-alanine, and L-alanine in Apollo regolith sample 70011 and found values of -21‰ to -33‰. These values are consistent with those seen in terrestrial biology and, together with the enantiomeric compositions of the proteinogenic amino acids, suggest that terrestrial biological contamination is a primary source of the

  20. Metabolic Response of Pakchoi Leaves to Amino Acid Nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-li; YU Wen-juan; ZHOU Qian; HAN Rui-feng; HUANG Dan-feng

    2014-01-01

    Different nitrogen (N) forms may cause changes in the metabolic profiles of plants. However, few studies have been conducted on the effects of amino acid-N on plant metabolic proifles. The main objective of this study was to identify primary metabolites associated with amino acid-N (Gly, Gln and Ala) through metabolic proifle analysis using gas chromatography-mass spectrometry (GC-MS). Plants of pakchoi (Brassica campestris L. ssp. chinensis L.), Huawang and Wuyueman cultivars, were grown with different nitrogen forms (i.e., Gly, Gln, Ala, NO3--N, and N starvation) applied under sterile hydroponic conditions. The fresh weight and plant N accumulation of Huawang were greater than those of Wuyueman, which indicates that the former exhibited better N-use efficiency than the latter. The physiological performances of the applied N forms were generally in the order of NO3--N>Gln>Gly>Ala. The metabolic analysis of leaf polar extracts revealed 30 amino acid N-responsive metabolites in the two pakchoi cultivars, mainly consisting of sugars, amino acids, and organic acids. Changes in the carbon metabolism of pakchoi leaves under amino acid treatments occurred via the accumulation of fructose, glucose, xylose, and arabinose. Disruption of amino acid metabolism resulted in accumulation of endogenous Gly in Gly treatment, Pro in Ala treatment, and Asn in three amino acid (Gly, Gln and Ala) treatments. By contrast, the levels of endogenous Gln and Leu decreased. However, this reduction varied among cultivars and amino acid types. Amino acid-N supply also affected the citric acid cycle, namely, the second stage of respiration, where leaves in Gly, Gln and Ala treatments contained low levels of malic, citric and succinic acids compared with leaves in NO3--N treatments. No signiifcant difference in the metabolic responses was observed between the two cultivars which differed in their capability to use N. The response of primary metabolites in pakchoi leaves to amino acid-N supply

  1. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    International Nuclear Information System (INIS)

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements

  2. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Alexandrina, E-mail: alexandrina.nan@itim-cj.ro; Bunge, Alexander; Turcu, Rodica [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  3. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    OpenAIRE

    Marko Kreft; Bak, Lasse K.; Waagepetersen, Helle S.; Arne Schousboe

    2012-01-01

    Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation.

  4. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    Directory of Open Access Journals (Sweden)

    Marko Kreft

    2012-04-01

    Full Text Available Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation.

  5. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    DEFF Research Database (Denmark)

    Kreft, Marko; Bak, Lasse Kristoffer; Waagepetersen, Helle S;

    2012-01-01

    Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pat......-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation....

  6. Method Development for Efficient Incorporation of Unnatural Amino Acids

    KAUST Repository

    Harris, Paul D.

    2014-04-01

    The synthesis of proteins bearing unnatural amino acids has the potential to enhance and elucidate many processes in biochemistry and molecular biology. There are two primary methods for site specific unnatural amino acid incorporation, both of which use the cell’s native protein translating machinery: in vitro chemical acylation of suppressor tRNAs and the use of orthogonal amino acyl tRNA synthetases. Total chemical synthesis is theoretically possible, but current methods severely limit the maximum size of the product protein. In vivo orthogonal synthetase methods suffer from the high cost of the unnatural amino acid. In this thesis I sought to address this limitation by increasing cell density, first in shake flasks and then in a bioreactor in order to increase the yield of protein per amount of unnatural amino acid used. In a parallel project, I used the in vitro chemical acylation system to incorporate several unnatural amino acids, key among them the fluorophore BODIPYFL, with the aim of producing site specifically fluorescently labeled protein for single molecule FRET studies. I demonstrated successful incorporation of these amino acids into the trial protein GFP, although incorporation was not demonstrated in the final target, FEN1. This also served to confirm the effectiveness of a new procedure developed for chemical acylation.

  7. Role of Branched-Chain Amino Acid Transport in Bacillus subtilis CodY Activity

    OpenAIRE

    Belitsky, Boris R.

    2015-01-01

    CodY is a branched-chain amino acid-responsive transcriptional regulator that controls the expression of several dozen transcription units in Bacillus subtilis. The presence of isoleucine, valine, and leucine in the growth medium is essential for achieving high activity of CodY and for efficient regulation of the target genes. We identified three permeases—BcaP, BraB, and BrnQ—that are responsible for the bulk of isoleucine and valine uptake and are also involved in leucine uptake. At least o...

  8. Influence of earthworm mucus and amino acids on tomato seedling growth and cadmium accumulation

    International Nuclear Information System (INIS)

    The effects on the growth of tomato seedlings and cadmium accumulation of earthworm mucus and a solution of amino acids matching those in earthworm mucus was studied through a hydroponic experiment. The experiment included four treatments: 5 mg Cd L-1 (CC), 5 mg Cd L-1 + 100 mL L-1 earthworm mucus (CE), 5 mg Cd L-1 + 100 mL L-1 amino acids solution (CA) and the control (CK). Results showed that, compared with CC treatment, either earthworm mucus or amino acids significantly increased tomato seedling growth and Cd accumulation but the increase was much higher in the CE treatment compared with the CA treatment. This may be due to earthworm mucus and amino acids significantly increasing the chlorophyll content, antioxidative enzyme activities, and essential microelement uptake and transport in the tomato seedlings. The much greater increase in the effect of earthworm mucus compared with amino acid treatments may be due to IAA-like substances in earthworm mucus. - Earthworm mucus increased tomato seedlings growth and Cd accumulation through increasing chlorophyll content, antioxidative enzyme activities, and essential microelement accumulation.

  9. Influence of earthworm mucus and amino acids on tomato seedling growth and cadmium accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shujie [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Hu Feng, E-mail: fenghu@njau.edu.c [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Li Huixin; Li Xiuqiang [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

    2009-10-15

    The effects on the growth of tomato seedlings and cadmium accumulation of earthworm mucus and a solution of amino acids matching those in earthworm mucus was studied through a hydroponic experiment. The experiment included four treatments: 5 mg Cd L{sup -1} (CC), 5 mg Cd L{sup -1} + 100 mL L{sup -1} earthworm mucus (CE), 5 mg Cd L{sup -1} + 100 mL L{sup -1} amino acids solution (CA) and the control (CK). Results showed that, compared with CC treatment, either earthworm mucus or amino acids significantly increased tomato seedling growth and Cd accumulation but the increase was much higher in the CE treatment compared with the CA treatment. This may be due to earthworm mucus and amino acids significantly increasing the chlorophyll content, antioxidative enzyme activities, and essential microelement uptake and transport in the tomato seedlings. The much greater increase in the effect of earthworm mucus compared with amino acid treatments may be due to IAA-like substances in earthworm mucus. - Earthworm mucus increased tomato seedlings growth and Cd accumulation through increasing chlorophyll content, antioxidative enzyme activities, and essential microelement accumulation.

  10. Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

    Science.gov (United States)

    Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.

    2016-01-01

    Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

  11. Structural and functional dynamics of Excitatory Amino Acid Transporters (EAAT

    Directory of Open Access Journals (Sweden)

    Thomas Rauen

    2014-09-01

    Full Text Available Glutamate transporters control the glutamate homeostasis in the central nervous system, and, thus, are not only crucial for physiological excitatory synaptic signaling, but also for the prevention of a large number of neurodegenerative diseases that are associated with excessive and prolonged presence of the neurotransmitter glutamate in the extracellular space. Until now, five subtypes of high-affinity glutamate transporters (excitatory amino acid transporters, EAATs 1–5 have been identified. These 5 high-affinity glutamate transporter subtypes belong to the solute carrier 1 (SLC1 family of transmembrane proteins: EAAT1/GLAST (SLC1A3, EAAT2/GLT1 (SLC1A2, EAAT3/EAAC1 (SLC1A1, EAAT4 (SLC1A6 and EAAT5 (SLC1A7. EAATs are secondary-active transporters, taking up glutamate into the cell against a substantial concentration gradient. The driving force for concentrative uptake is provided by the co-transport of Na+ ions and the counter-transport of one K+ in a step independent of the glutamate translocation step. Due to the electrogenicity of transport, the transmembrane potential can also act as driving force. Glutamate transporters are also able to run in reverse, resulting in glutamate release from cells. Due to these important physiological functions, glutamate transporter expression and, therefore, the transport rate, are tightly regulated. The EAAT protein family are structurally expected to be highly similar, however, these transporters show a functional diversity that ranges from high capacity glutamate uptake systems (EAATs 1–3 to receptor-like glutamate activated anion channels (EAATs 4–5. Here, we provide an update on most recent progress made on EAAT’s molecular transport mechanism, structure-function relationships, pharmacology, and will add recent insights into mechanism of rapid membrane trafficking of glutamate transporters.

  12. Amino acid residues important for substrate specificity of the amino acid permeases Can I p and Gnp I p in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Regenberg, Birgitte; Kielland-Brandt, M.C.

    2001-01-01

    mutations affecting six predicted domains (helices III and X, and loops 1. 2, 6 and 7) of the permeases. Helix III and loop 7 are candidates for domains in direct contact with the transported amino acid. Helix III was affected in both CAN1 (Y173H, Y173D) and GNP1 (W239C) mutants and has previously been...... found to be important for substrate preference in other members of the family. Furthermore, the mutations affecting loop 7 (residue T354, S355, Y356) are close to a glutamate side chain (E367) potentially interacting with the positively charged substrate, a notion supported by conservation of the side......Deletion of the general amino acid permease gene GAP1 abolishes uptake of L-citrulline in Saccharomyces cerevisiae, resulting in the inability to grow on L-citrulline as sole nitrogen source. Selection for suppressor mutants that restored growth on L-citrulline led to isolation of 21 mutations in...

  13. Profile of Fatty Acids, Amino Acids, Carotenoid Total, and α-Tocopherol from Flying Fish Eggs

    Directory of Open Access Journals (Sweden)

    Aulia Azka

    2015-12-01

    Full Text Available Flying fish are found in waters of eastern Indonesia, which until now is still limited information about nutritional content. The purpose of this research was determine the composition of fatty acids, amino acids, total carotenoids, α-tocopherol flying fish eggs (Hyrundicthys sp.. The composition of fatty acid was measured by gas chromatography (GC, while amino acids, total carotenoids, α-tocopherol was measured by High performanced Liquid Chromatography (HPLC. Egg contained 22 fatty acids such as saturated fatty acid 29.71%, monounsaturated fatty acid 7.86%, and polysaturated fatty acid 13.64%. The result showed that eggs flying fish contained 17 amino acids, such as essential amino acid 14.96% and non-essential amino acids 20.27%. Eggs contained a total carotenoid of 245.37 ppm. α-tocopherol content of flying fish eggs by 1.06 ppm.

  14. N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

    International Nuclear Information System (INIS)

    With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

  15. The Amino Acid Composition of the Sutter's Mill Carbonaceous Chondrite

    Science.gov (United States)

    Glavin, D. P.; Burton, A. S.; Elsila, J. E.; Dworkin, J. P.; Yin, Q. Z.; Cooper, G.; Jenniskens, P.

    2012-01-01

    In contrast to the Murchison meteorite which had a complex distribution of amino acids with a total C2 to Cs amino acid abundance of approx.14,000 parts-per-billion (ppb) [2], the Sutters Mill meteorite was found to be highly depleted in amino acids. Much lower abundances (approx.30 to 180 ppb) of glycine, beta-alanine, L-alanine and L-serine were detected in SM2 above procedural blank levels indicating that this meteorite sample experienced only minimal terrestrial amino acid contamination after its fall to Earth. Carbon isotope measurements will be necessary to establish the origin of glycine and beta-alanine in SM2. Other non-protein amino acids that are rare on Earth, yet commonly found in other CM meteorites such as aaminoisobutyric acid (alpha-AIB) and isovaline, were not identified in SM2. However, traces of beta-AIB (approx.1 ppb) were detected in SM2 and could be" extraterrestrial in origin. The low abundances of amino acids in the Sutter's Mill meteorite is consistent with mineralogical evidence that at least some parts of the Sutter's Mill meteorite parent body experienced extensive aqueous and/or thermal alteration.

  16. Updates on industrial production of amino acids using Corynebacterium glutamicum.

    Science.gov (United States)

    Wendisch, Volker F; Jorge, João M P; Pérez-García, Fernando; Sgobba, Elvira

    2016-06-01

    L-Amino acids find various applications in biotechnology. L-Glutamic acid and its salts are used as flavor enhancers. Other L-amino acids are used as food or feed additives, in parenteral nutrition or as building blocks for the chemical and pharmaceutical industries. L-amino acids are synthesized from precursors of central carbon metabolism. Based on the knowledge of the biochemical pathways microbial fermentation processes of food, feed and pharma amino acids have been developed. Production strains of Corynebacterium glutamicum, which has been used safely for more than 50 years in food biotechnology, and Escherichia coli are constantly improved using metabolic engineering approaches. Research towards new processes is ongoing. Fermentative production of L-amino acids in the million-ton-scale has shaped modern biotechnology and its markets continue to grow steadily. This review focusses on recent achievements in strain development for amino acid production including the use of CRISPRi/dCas9, genome-reduced strains, biosensors and synthetic pathways to enable utilization of alternative carbon sources. PMID:27116971

  17. Covalently functionalized graphene sheets with biocompatible natural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Mallakpour, Shadpour, E-mail: mallak@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Abdolmaleki, Amir, E-mail: abdolmaleki@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Borandeh, Sedigheh [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of)

    2014-07-01

    Graphene sheets were covalently functionalized with aromatic–aliphatic amino acids (phenylalanine and tyrosine) and aliphatic amino acids (alanine, isoleucine, leucine, methionine and valine) by simple and green procedure. For this aim, at first natural graphite was converted into graphene oxide (GO) through strong oxidation procedure; then, based on the surface-exposed epoxy and carboxylic acid groups in GO solid, its surface modification with naturally occurring amino acids, occurred easily throughout the corresponding nucleophilic substitution and condensation reactions. Amino acid functionalized graphene demonstrates stable dispersion in water and common organic solvents. Fourier transform infrared, Raman and X-ray photoelectron spectroscopies, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy were used to investigate the nanostructures and properties of prepared materials. Each amino acid has different considerable effects on the structure and morphology of the pure graphite, from increasing the layer spacing to layer scrolling, based on their structures, functional groups and chain length. In addition, therogravimetric analysis was used for demonstrating a successful grafting of amino acid molecules to the surface of graphene.

  18. Sugar amino acids and related molecules: Some recent developments

    Indian Academy of Sciences (India)

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

    2004-06-01

    To meet the growing demands for the development of new molecular entities for discovering new drugs and materials, organic chemists have started working on many new concepts that can help to assimilate knowledge-based structural diversities more efficiently than ever before. 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. In recent years, sugar amino acids have been used extensively in the area of peptidomimetic studies. Advances made in the area of combinatorial chemistry can provide the necessary technological support for rapid compilations of sugar amino acidbased libraries exploiting the diversities of their carbohydrate frameworks and well-developed solidphase peptide synthesis methods. This perspective article chronicles some of the recent applications of various sugar amino acids, furan amino acids, pyrrole amino acids etc. and many other related building blocks in wide-ranging peptidomimetic studies.

  19. Interconversions of amino acids in maturing wheat grains

    International Nuclear Information System (INIS)

    All the protein amino acids (U-14C labelled) were supplied directly to the developing spikes of spring wheat, mainly through a split stem. At maturity the proteins were fractionated into two or four Osborne fractions and the total activity was measured. The activity recovered in proteins varied from a few per cent to more than 75%. The highest recovery was found when 14C was supplied in histidine, valine, phenylalanine, leucine or tryptophan. When sugars were supplied only 3-5% of their activity was recovered in proteins, while aspartic acid, alanine, glutamic acid, proline and cysteine gave 10-20% recovery in proteins, and great respiratory losses must have occurred. The label could be transferred to every protein amino acid. Groups of amino acids showed a very similar distribution of the recovered 14C. The activity from glutamic acid, glutamine, alanine, aspartic acid and proline was mainly recovered in glutamic acid, proline and arginine, with a similar distribution for 14C transferred from lysine, isoleucine, arginine, threonine, asparagine and cysteine; however, 40-70% was recovered in the label source. Histidine, phenylalanine, leucine, tyrosine and tryptophan showed very little conversion. Activity from sugars was more spread than for amino acids. Unlabelled arginine or ornithine inhibited the conversion of glutamic acid to arginine, while lysine inhibited the conversion of aspartic acid to lysine. The results clearly indicate metabolic sites in the grain where the received amino acids are converted to amino acids that fit in with the genetic codes for specific protein synthesis. Different conversion patterns seemed to be linked to different fractions, indicating different metabolic activity in different parts of the grain and probably also in different parts of the cells in the starchy endosperm

  20. Displacement of carbon-14 labelled amino acids from leaves

    International Nuclear Information System (INIS)

    The displacement of amino acids from nature leaves was investigated. The amino acids (Ala, Asn, Asp, Glu, Gln, Val, Leu, Lys, Ser, Pro) were applied on the leaves in L-form, uniformly labelled with 14C, and the type and direction of displacement have been observed. Most of the studies have been carried out on bush beans aged 3 to 4 weeks. The experiments were carried out in climatic chambers; in one case, barley plants just reaching maturity were used. In order to find out whether the applied amino acids were also displaced in their original form, freeze-dried plants were extracted and the 14C activity of the various fraction was determined. The radioactivity of some free amino acids was determined after two-dimensional separation by thin film chromatography. (orig./HK)

  1. Azide- and alkyne-derivatised α-amino acids

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Pedersen, D.S.

    2012-01-01

    With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way for their...... synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention to...... unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...

  2. Detecting coevolving amino acid sites using Bayesian mutational mapping

    DEFF Research Database (Denmark)

    Dimmic, Matthew W.; Hubisz, Melissa J.; Bustamente, Carlos D.;

    2005-01-01

    Motivation: The evolution of protein sequences is constrained by complex interactions between amino acid residues. Because harmful substitutions may be compensated for by other substitutions at neighboring sites, residues can coevolve. We describe a Bayesian phylogenetic approach to the detection...

  3. Detection of COL III in Parchment by Amino Acid Analysis

    DEFF Research Database (Denmark)

    Vestergaard Poulsen Sommer, Dorte; Larsen, René

    2016-01-01

    Cultural heritage parchments made from the reticular dermis of animals have been subject to studies of deterioration and conservation by amino acid analysis. The reticular dermis contains a varying mixture of collagen I and III (COL I and III). When dealing with the results of the amino acid...... analyses, till now the COL III content has not been taken into account. Based on the available amino acid sequences we present a method for determining the amount of COL III in the reticular dermis of new and historical parchments calculated from the ratio of Ile/Val. We find COL III contents between 7 and...... 32 % in new parchments and between 0.2 and 40 % in the historical parchments. This is consistent with results in the literature. The varying content of COL III has a significant influence on the uncertainty of the amino acid analysis. Although we have not found a simple correlation between the COL...

  4. Comparing Amino Acid Abundances and Distributions Across Carbonaceous Chondrite Groups

    Science.gov (United States)

    Burton, Aaron S.; Callahan, Michael P.; Glavin, Daniel P.; Elsila, Jamie E.; Dworkin, Jason P.

    2012-01-01

    Meteorites are grouped according to bulk properties such as chemical composition and mineralogy. These parameters can vary significantly among the different carbonaceous chondrite groups (CI, CM, CO, CR, CH, CB, CV and CK). We have determined the amino acid abundances of more than 30 primary amino acids in meteorites from each of the eight groups, revealing several interesting trends. There are noticeable differences in the structural diversity and overall abundances of amino acids between meteorites from the different chondrite groups. Because meteorites may have been an important source of amino acids to the prebiotic Earth and these organic compounds are essential for life as we know it, the observed variations of these molecules may have been important for the origins of life.

  5. Reconstructing a Flavodoxin Oxidoreductase with Early Amino Acids

    Directory of Open Access Journals (Sweden)

    Hong-Yu Zhang

    2013-06-01

    Full Text Available Primitive proteins are proposed to have utilized organic cofactors more frequently than transition metals in redox reactions. Thus, an experimental validation on whether a protein constituted solely by early amino acids and an organic cofactor can perform electron transfer activity is an urgent challenge. In this paper, by substituting “late amino acids (C, F, M, T, W, and Y” with “early amino acids (A, L, and V” in a flavodoxin, we constructed a flavodoxin mutant and evaluated its characteristic properties. The major results showed that: (1 The flavodoxin mutant has structural characteristics similar to wild-type protein; (2 Although the semiquinone and hydroquinone flavodoxin mutants possess lower stability than the corresponding form of wild-type flavodoxin, the redox potential of double electron reduction Em,7 (fld reached −360 mV, indicating that the flavodoxin mutant constituted solely by early amino acids can exert effective electron transfer activity.

  6. Microbes Promote Amino Acid Harvest to Rescue Undernutrition in Drosophila

    Directory of Open Access Journals (Sweden)

    Ryuichi Yamada

    2015-02-01

    Full Text Available Microbes play an important role in the pathogenesis of nutritional disorders such as protein-specific malnutrition. However, the precise contribution of microbes to host energy balance during undernutrition is unclear. Here, we show that Issatchenkia orientalis, a fungal microbe isolated from field-caught Drosophila melanogaster, promotes amino acid harvest to rescue the lifespan of undernourished flies. Using radioisotope-labeled dietary components (amino acids, nucleotides, and sucrose to quantify nutrient transfer from food to microbe to fly, we demonstrate that I. orientalis extracts amino acids directly from nutrient-poor diets and increases protein flux to the fly. This microbial association restores body mass, protein, glycerol, and ATP levels and phenocopies the metabolic profile of adequately fed flies. Our study uncovers amino acid harvest as a fundamental mechanism linking microbial and host metabolism, and highlights Drosophila as a platform for quantitative studies of host-microbe relationships.

  7. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to...... undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  8. Stimulation of the amino acid transporter SLC6A19 by JAK2

    Energy Technology Data Exchange (ETDEWEB)

    Bhavsar, Shefalee K.; Hosseinzadeh, Zohreh; Merches, Katja; Gu, Shuchen [Department of Physiology I, University of Tuebingen (Germany); Broeer, Stefan [Research School of Biology, Australian National University (Australia); Lang, Florian, E-mail: florian.lang@uni-tuebingen.de [Department of Physiology I, University of Tuebingen (Germany)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer The amino acid transporter SLC6A19 is upregulated by Janus kinase-2 JAK2. Black-Right-Pointing-Pointer The {sup V617F}JAK2 mutant, causing myeloproliferative disease, is more effective. Black-Right-Pointing-Pointer JAK2 inhibitor AG490 reverses stimulation of SLC6A19 by {sup V617F}JAK2. Black-Right-Pointing-Pointer JAK2 enhances SLC6A19 protein insertion into the cell membrane. Black-Right-Pointing-Pointer SLC6A19 may contribute to amino acid uptake into {sup V617F}JAK2 expressing tumor cells. -- Abstract: JAK2 (Janus kinase-2) is expressed in a wide variety of cells including tumor cells and contributes to the proliferation and survival of those cells. The gain of function mutation {sup V617F}JAK2 mutant is found in the majority of myeloproliferative diseases. Cell proliferation depends on the availability of amino acids. Concentrative cellular amino acid uptake is in part accomplished by Na{sup +} coupled amino acid transport through SLC6A19 (B(0)AT). The present study thus explored whether JAK2 activates SLC6A19. To this end, SLC6A19 was expressed in Xenopus oocytes with or without wild type JAK2, {sup V617F}JAK2 or inactive {sup K882E}JAK2 and electrogenic amino acid transport determined by dual electrode voltage clamp. In SLC6A19-expressing oocytes but not in oocytes injected with water or JAK2 alone, the addition of leucine (2 mM) to the bath generated a current (I{sub le}), which was significantly increased following coexpression of JAK2 or {sup V617F}JAK2, but not by coexpression of {sup K882E}JAK2. Coexpression of JAK2 enhanced the maximal transport rate without significantly modifying the affinity of the carrier. Exposure of the oocytes to the JAK2 inhibitor AG490 (40 {mu}M) resulted in a gradual decline of I{sub le}. According to chemiluminescence JAK2 enhanced the carrier protein abundance in the cell membrane. The decline of I{sub le} following inhibition of carrier insertion by brefeldin A (5 {mu}M) was similar

  9. Representation of protein-sequence information by amino acid subalphabets

    DEFF Research Database (Denmark)

    Andersen, C.A.F.; Brunak, Søren

    2004-01-01

    -sequence information, using machine learning strategies, where the primary goal is the discovery of novel powerful representations for use in AI techniques. In the case of proteins and the 20 different amino acids they typically contain, it is also a secondary goal to discover how the current selection of amino acids......-which now are common in proteins-might have emerged from simpler selections, or alphabets, in use earlier during the evolution of living organisms....

  10. Co2 chemosorption by functionalized amino acid derivatives

    DEFF Research Database (Denmark)

    2015-01-01

    The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid.......The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid....

  11. Review: Taurine: A “very essential” amino acid

    OpenAIRE

    Ripps, Harris; Shen, Wen

    2012-01-01

    Taurine is an organic osmolyte involved in cell volume regulation, and provides a substrate for the formation of bile salts. It plays a role in the modulation of intracellular free calcium concentration, and although it is one of the few amino acids not incorporated into proteins, taurine is one of the most abundant amino acids in the brain, retina, muscle tissue, and organs throughout the body. Taurine serves a wide variety of functions in the central nervous system, from development to cyto...

  12. FLU, an amino acid substitution model for influenza proteins

    OpenAIRE

    Gascuel Olivier; Le Quang; Dang Cuong; Le Vinh

    2010-01-01

    Abstract Background The amino acid substitution model is the core component of many protein analysis systems such as sequence similarity search, sequence alignment, and phylogenetic inference. Although several general amino acid substitution models have been estimated from large and diverse protein databases, they remain inappropriate for analyzing specific species, e.g., viruses. Emerging epidemics of influenza viruses raise the need for comprehensive studies of these dangerous viruses. We p...

  13. Importance of amino acids on vasopressin-stimulated water flow.

    OpenAIRE

    Carvounis, C P; Carvounis, G; Wilk, B J

    1985-01-01

    The presence of several naturally occurring amino acids in the serosal bath of toad urinary bladder significantly alters the hydrosmotic response of this tissue to vasopressin. We found that histidine, glutamate, and lysine increase vasopressin-stimulated water flow by 75%, 60%, and 43%, respectively. In contrast, alanine did not alter vasopressin-stimulated water flow, whereas glutamine decreased it by 25%. The effect of each amino acid represents intracellular events because their effects o...

  14. Amino Acid Interaction Network Prediction Using Multi-Objective Optimization

    Directory of Open Access Journals (Sweden)

    Md. Shiplu Hawlader

    2014-01-01

    Full Text Available Protein can be represented by amino acid interaction network. This network is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. This interaction network is the first step of proteins three-dimensional structure prediction. In this paper we present a multi-objective evolutionary algorithm for interaction prediction and ant colony probabilistic optimization algorithm is used to confirm the interaction.

  15. Pharmacological screening of glycine amino acid prodrug of acetaminophen

    OpenAIRE

    Arun Parashar

    2015-01-01

    Objective: To develop an amino acid prodrug of acetaminophen with comparable therapeutic profile and less hepatotoxicity than acetaminophen. Materials and Methods: Acetaminophen prodrug was synthesized by esterification between the carboxyl group of amino acid glycine and hydroxyl group of acetaminophen. Analgesic, antipyretic, ulcer healing, and hepatotoxic activities were performed on Wistar rats in this study. Results: Prodrug showed a 44% inhibition in writhings as compared to 53....

  16. Extraterrestrial Amino Acids in Ureilites Including Almahata Sitta

    Science.gov (United States)

    Burton, A. S.; Glavin, D. P.; Callahan, M. P.; Dworkin, J. P.

    2011-01-01

    Ureilites are a class of meteorites that lack chondrules (achondrites) but have relatively high carbon abundances, averaging approx.3 wt %. Using highly sensitive liquid chromatography coupled with UV fluorescence and time-of-flight mass spectrometry (LC-FD/ToF-MS), it was recently determined that there are amino acids in. fragment 94 of the Almahata Sitta ureilite[l]. Based on the presence of amino acids that are rare in the Earth's biosphere, as well as the near-racemic enantiomeric ratios of marry of the more common amino acids, it was concluded that most of the detected amino acids were indigenous to the meteorite. Although the composition of the Almahata Sitta ureilite appears to be unlike other recovered ureilites, the discovery of amino acids in this meteorite raises the question of whether other ureilites rnav also contain amino acids. Herein we present the results of LC-FDlTo.F-MS analyses of: a sand sample from the Almahata Sitta strewn held, Almahata Sitta fragments 425 (an ordinary H5 chondrite) and 427 (ureilite), as well as an Antarctic ureilite (Allan lulls, ALHA 77257).

  17. The preferences of orientations between the Pairs of amino acids

    Institute of Scientific and Technical Information of China (English)

    Chen Ying; Wang Jun; Wang Wei

    2007-01-01

    In this work,we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned.It is found that there are common preferences of orientations (70°,30°,140°) and (110°,340°,100°) for various pairs of amino acids.Different side chains may strengthen or weaken the common preferences,which is related to the effect of packing.Some amino acids having specific local flexibility may possess some preferences of orientations besides the common ones,such as (10°,280°,210°) .Another analysis on the pairs of the amino acids with different secondary-structure preferences shows that the directional interaction may affect the distribution of orientation more effectively than the packing or local flexibility.All these results provide us some insight of the organization of amino acids in protein,and their relation with some related interactions.

  18. Alterations in Plasma Amino Acid Levels in Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Banavara Narasimhamurthy Girish

    2011-01-01

    Full Text Available Context Dietary proteins and amino acids can modulate pancreatic function. Objective Our aim was to estimate the levels of plasma amino acids in chronic pancreatitis patients and study their relationship with disease characteristics as well as exocrine and endocrine insufficiency. Patients One hundred and seventy-five consecutive adult patients with chronic pancreatitis: 84 patients with alcoholic chronic pancreatitis and 91 patients with tropical chronic pancreatitis. One hundred and thirteen healthy controls were also studied. Design Prospective study. Main outcome measures Disease characteristics and imaging features were recorded. Plasma-free amino acid levels were estimated using reverse-phase high-performance liquid chromatography. Polyclonal antibody ELISA was used to assess pancreatic fecal elastase-1. Results The majority of the plasma free amino acid levels decreased in chronic pancreatitis patients whereas glutamate, glycine, proline and lysine were elevated as compared to the controls. Multivariate logistic regression analysis revealed that the decrease in branched chain amino acid concentration was significantly associated with the presence of diabetes and low fecal elastase-1. In addition, a significant positive correlation was observed between branched chain amino acids and pancreatic elastase-1 (rs=0.724, P

  19. Child Stunting is Associated with Low Circulating Essential Amino Acids

    Science.gov (United States)

    Semba, Richard D.; Shardell, Michelle; Sakr Ashour, Fayrouz A.; Moaddel, Ruin; Trehan, Indi; Maleta, Kenneth M.; Ordiz, M. Isabel; Kraemer, Klaus; Khadeer, Mohammed A.; Ferrucci, Luigi; Manary, Mark J.

    2016-01-01

    Background Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of children. Methods We used a targeted metabolomics approach to measure serum amino acids, glycerophospholipids, sphingolipids, and other metabolites using liquid chromatography-tandem mass spectrometry in 313 children, aged 12–59 months, from rural Malawi. Children underwent anthropometry. Findings Sixty-two percent of the children were stunted. Children with stunting had lower serum concentrations of all nine essential amino acids (tryptophan, isoleucine, leucine, valine, methionine, threonine, histidine, phenylalanine, lysine) compared with nonstunted children (p children had significantly lower serum concentrations of conditionally essential amino acids (arginine, glycine, glutamine), non-essential amino acids (asparagine, glutamate, serine), and six different sphingolipids compared with nonstunted children. Stunting was also associated with alterations in serum glycerophospholipid concentrations. Interpretation Our findings support the idea that children with a high risk of stunting may not be receiving an adequate dietary intake of essential amino acids and choline, an essential nutrient for the synthesis of sphingolipids and glycerophospholipids.

  20. Release of selected amino acids from zinc carriers.

    Science.gov (United States)

    Dyja, Renata; Dolińska, Barbara; Ryszka, Florian

    2016-06-01

    The paper deals with the results of an investigation of the release of selected amino acids (histidine, tryptophan, tyrosine) from model suspensions prepared by co-precipitation with zinc chloride. It has been proven that the influence of the Zn(II)/amino acid molar ratio on dissolution profiles of the tested amino acids and dissolution half-life (t1/2) of histidine or tryptophan is significant. The amount of amino acid in the dispersed phase (supporting dose) is a determinant of the amino acid release profile. There is a minimal supporting dose (30.0 μmol of histidine or 17.4 μmol of tryptophan) that provides release of similar amounts of amino acid (4.1-4.6 μmol of histidine or 8.7-9.9 μmol of tryptophan) after the same time intervals. The tyrosine release profiles follow first order kinetics since the supporting dose (0.9-11.2 μmol) is limited by the tyrosine low solubility in water. PMID:27279069

  1. Did Evolution Select a Nonrandom "Alphabet" of Amino Acids?

    Science.gov (United States)

    Philip, Gayle K.; Freeland, Stephen J.

    2011-04-01

    The last universal common ancestor of contemporary biology (LUCA) used a precise set of 20 amino acids as a standard alphabet with which to build genetically encoded protein polymers. Considerable evidence indicates that some of these amino acids were present through nonbiological syntheses prior to the origin of life, while the rest evolved as inventions of early metabolism. However, the same evidence indicates that many alternatives were also available, which highlights the question: what factors led biological evolution on our planet to define its standard alphabet? One possibility is that natural selection favored a set of amino acids that exhibits clear, nonrandom properties - a set of especially useful building blocks. However, previous analysis that tested whether the standard alphabet comprises amino acids with unusually high variance in size, charge, and hydrophobicity (properties that govern what protein structures and functions can be constructed) failed to clearly distinguish evolution's choice from a sample of randomly chosen alternatives. Here, we demonstrate unambiguous support for a refined hypothesis: that an optimal set of amino acids would spread evenly across a broad range of values for each fundamental property. Specifically, we show that the standard set of 20 amino acids represents the possible spectra of size, charge, and hydrophobicity more broadly and more evenly than can be explained by chance alone.

  2. Determination of amino acids in industrial effluents contaminated soil

    International Nuclear Information System (INIS)

    38 samples of soil for 19 locations partially irrigated on the effluents of sugar mill and oil andghee mill, bottom sediments of evaporation ponds of sugar and fertilizer industries were collected and analyzed for amino acids after acid digestion by gas chromatography using pre column derivatization with trifluroacetyleacetone and ethyl chloroformate. The results obtained were compared with the soil samples irrigated with fresh water. The soil samples were also analyzed for pH, total nitrogen contents and organic carbon. Nine essential (leucine (Leu), threonine (Thr), lysine (Lys), L-phenylalanine (Phe), tryptophan (Trp), histadine (His), L-valine (Val), methionine (Met) and isoleucine Ile) and ten non-essential ( alanine (Ala), cysteine (Cys), asparagine (Asn), glutamic acid (Glu), serine (Ser), glycine (Gly), proline (Pro), Glutamine (Gln), aspartic acid (Asp), tyrosine (Tyr)) amino acids were analyzed 13-15 amino acids were identified and determined quantitatively from soil samples. Amino acids Met, Asn, Gln and Trp were observed absent from all the samples. The variation in the amino acids contents in soil with the industrial effluents added and total nitrogen and organic carbon is discussed. (author)

  3. 77 FR 65537 - Requirements for Patent Applications Containing Nucleotide Sequence and/or Amino Acid Sequence...

    Science.gov (United States)

    2012-10-29

    ... Amino Acid Sequence Disclosures ACTION: Proposed collection; comment request. SUMMARY: The United States....'' SUPPLEMENTARY INFORMATION: I. Abstract Patent applications that contain nucleotide and/or amino acid...

  4. 21 CFR 172.320 - Amino acids.

    Science.gov (United States)

    2010-04-01

    ...-Cysteine L-Cystine L-Glutamic acid L-Glutamine Aminoacetic acid (glycine) L-Histidine L-Isoleucine L... following: L-Asparagine L-Aspartic acid L-Glutamine L-Histidine (c) The additive(s) is used or intended for....4 Aminoacetic acid (glycine) 3.5 L-Histidine 2.4 L-Isoleucine 6.6 L-Leucine 8.8 L-Lysine 6.4 L-...

  5. Amino acid profile during exercise and training in Standardbreds.

    Science.gov (United States)

    Westermann, C M; Dorland, L; Wijnberg, I D; de Sain-van der Velden, M G M; van Breda, E; Barneveld, A; de Graaf-Roelfsema, E; Keizer, H A; van der Kolk, J H

    2011-08-01

    The objective of this study is to assess the influence of acute exercise, training and intensified training on the plasma amino acid profile. In a 32-week longitudinal study using 10 Standardbred horses, training was divided into four phases, including a phase of intensified training for five horses. At the end of each phase, a standardized exercise test, SET, was performed. Plasma amino acid concentrations before and after each SET were measured. Training significantly reduced mean plasma aspartic acid concentration, whereas exercise significantly increased the plasma concentrations of alanine, taurine, methionine, leucine, tyrosine and phenylalanine and reduced the plasma concentrations of glycine, ornithine, glutamine, citrulline and serine. Normally and intensified trained horses differed not significantly. It is concluded that amino acids should not be regarded as limiting training performance in Standardbreds except for aspartic acid which is the most likely candidate for supplementation. PMID:20863542

  6. Urinary Amino Acid Analysis: A Comparison of iTRAQ®-LC-MS/MS, GC-MS, and Amino Acid Analyzer

    OpenAIRE

    Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Peter J Oefner

    2009-01-01

    Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatog...

  7. Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

    International Nuclear Information System (INIS)

    Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N2O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N2O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N2O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N2O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N2O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N2O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

  8. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  9. Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl Hydrazide and Amino Acid-(N'-Nicotinoyl Hydrazide Derivatives

    Directory of Open Access Journals (Sweden)

    Sherine N. Khattab

    2005-09-01

    Full Text Available The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl- and N- Boc-amino acid-(N`-nicotinoyl hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl hydrazide hydrochloride salts (7a-7e and amino acid-(N`- nicotinoyl hydrazide hydrochloride salts (8a-8e. These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli.

  10. Biodistribution of [11C] methylaminoisobutyric acid, a tracer for PET studies on system A amino acid transport in vivo

    International Nuclear Information System (INIS)

    [N-methyl-11C]α-Methylaminoisobutyric acid (11C-MeAIB) is a potentially useful tracer for positron emission tomography (PET) studies on hormonally regulated system A amino acid transport. 11C-MeAIB is a metabolically stable amino acid analogue specific for system A amino acid transport. We evaluated the biodistribution of 11C-MeAIB in rats and humans to estimate the usefulness of the tracer for in vivo human PET studies, for example, on regulation of system A amino acid transport and on tumour imaging. Healthy Sprague-Dawley rats (n=14) were killed 5, 20, 40 or 60 min after the injection of 11C-MeAIB, and the tissue samples were weighed and counted for 11C radioactivity. Ten lymphoma patients with relatively limited tumour burden underwent whole-body (WB) PET imaging with 11C-MeAIB. In addition, three other patients had dynamic PET scanning of the head and neck area, and the tracer uptake was quantitated by calculating the kinetic influx constants (Ki values) for the tracer. In animal studies, the highest activity was detected in the kidney, pancreas, adrenal gland and intestines. In humans, the highest activity was found in the salivary glands, and after that in the kidney and pancreas, similar to the results in animal studies. Rapid uptake was also detected in the skeletal muscle. In the graphical analysis, linear plots were obtained, and the mean fractional tracer uptake values (Ki) of the parotid glands (n=3) and cervical muscles (n=3) were 0.039±0.008 min-1 and 0.013±0.006 min-1, respectively. The Ki value of the tumour (n=1) was 0.064 min-1. Higher uptake of 11C-MeAIB into the tumour tissue was encountered. These results encourage further 11C-MeAIB PET studies in humans on the physiology and pathology of system A amino acid transport and on tumour detection. (orig.)

  11. Silicone hydrogels grafted with natural amino acids for ophthalmological application.

    Science.gov (United States)

    Xu, Chen; He, Ruiyu; Xie, Binbin; Ismail, Muhammad; Yao, Chen; Luan, Jie; Li, Xinsong

    2016-09-01

    In this report, protein repelling silicone hydrogels with improved hydrophilicity were prepared by photo-polymerization of silicone-containing monomer and glycidyl methacrylate followed by grafting zwitterionic amino acids. The grafted silicone hydrogels possessed excellent hydrophilic surfaces due to the enrichment of amino acids, which was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle, and equilibrium water content measurements. Remarkable resistance to bovine serum albumin and lysozyme fouling was observed for the silicone hydrogels immobilized with neutrally charged amino acids because of the formation of zwitterionic surfaces with pairs of protonated secondary ammonium cations and deprotonated carboxyl anions. Meanwhile, the silicone hydrogels grafted with positively or negatively charged amino acids were able to repulse same charged protein with reduced deposition and attract oppositely charged protein with increased adsorption. Preliminary cytotoxicity test indicated that the zwitterionic silicone hydrogels were non-cytotoxic. Similarly, three types of natural amino acids, including serine, aspartic acid and histidine, modified silicone hydrogel contact lenses exhibited excellent hydrophilicity and non-damage to the rabbit's eyes, but only serine modified zwitterionic contact lens showed superior protein fouling resistance compared with the current commercial hydrogel contact lens, which may have great potential application in ophthalmology. PMID:27297564

  12. Thyroid peroxidase activity is inhibited by amino acids

    Directory of Open Access Journals (Sweden)

    D.P. Carvalho

    2000-03-01

    Full Text Available Normal in vitro thyroid peroxidase (TPO iodide oxidation activity was completely inhibited by a hydrolyzed TPO preparation (0.15 mg/ml or hydrolyzed bovine serum albumin (BSA, 0.2 mg/ml. A pancreatic hydrolysate of casein (trypticase peptone, 0.1 mg/ml and some amino acids (cysteine, tryptophan and methionine, 50 µM each also inhibited the TPO iodide oxidation reaction completely, whereas casamino acids (0.1 mg/ml, and tyrosine, phenylalanine and histidine (50 µM each inhibited the TPO reaction by 54% or less. A pancreatic digest of gelatin (0.1 mg/ml or any other amino acid (50 µM tested did not significantly decrease TPO activity. The amino acids that impair iodide oxidation also inhibit the TPO albumin iodination activity. The inhibitory amino acids contain side chains with either sulfur atoms (cysteine and methionine or aromatic rings (tyrosine, tryptophan, histidine and phenylalanine. Among the amino acids tested, only cysteine affected the TPO guaiacol oxidation reaction, producing a transient inhibition at 25 or 50 µM. The iodide oxidation inhibitory activity of cysteine, methionine and tryptophan was reversed by increasing iodide concentrations from 12 to 18 mM, while no such effect was observed when the cofactor (H2O2 concentration was increased. The inhibitory substances might interfere with the enzyme activity by competing with its normal substrates for their binding sites, binding to the free substrates or reducing their oxidized form.

  13. Excitatory amino acid receptor ligands: resolution, absolute stereochemistry, and enantiopharmacology of 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid

    DEFF Research Database (Denmark)

    Johansen, T N; Ebert, B; Bräuner-Osborne, Hans; Didriksen, M; Christensen, I T; Søby, K K; Madsen, U; Krogsgaard-Larsen, P; Brehm, L

    1998-01-01

    M) were equipotent as inhibitors of CaCl2-dependent [3H]-(S)-glutamic acid binding, neither enantiomer showed significant affinity for the synaptosomal (S)-glutamic acid uptake system(s). AMPA receptor affinity (IC50 = 0.48 microM) and agonism (EC50 = 17 microM) were shown to reside exclusively in the S......(RS)-2-Amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid (Bu-HIBO, 6) has previously been shown to be an agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors and an inhibitor of CaCl2-dependent [3H]-(S)-glutamic acid binding (J. Med. Chem. 1992, 35, 3512...... observations together indicate that the potentiation of the AMPA receptor agonism of 7 by 8 is not mediated by metabotropic (S)-glutamate receptors but rather by the CaCl2-dependent (S)-glutamic acid binding system, which shows the characteristics of a transport mechanism. After intravenous administration in...

  14. Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km

    DEFF Research Database (Denmark)

    Madsen, Klavs; MacLean, David A; Kiens, Bente;

    1996-01-01

    This study was undertaken to determine the effects of ingesting either glucose (trial G) or glucose plus branched-chain amino acids (BCAA: trial B), compared with placebo (trial P), during prolonged exercise. Nine well-trained cyclists with a maximal oxygen uptake of 63.1 +/- 1.5 ml O2. min-1.kg-1...

  15. Promiscuous Seven Transmembrane Receptors Sensing L-α-amino Acids

    DEFF Research Database (Denmark)

    Smajilovic, Sanela; Wellendorph, Petrine; Bräuner-Osborne, Hans

    2014-01-01

    A number of nutrient sensing seven trans-membrane (7TM) receptors have been identified and characterized over the past few years. While the sensing mechanisms to carbohydrates and free fatty acids are well understood, the molecular basis of amino acid sensing has recently come to the limelight. T...

  16. Boron-containing amino carboxylic acid compounds and uses thereof

    International Nuclear Information System (INIS)

    Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed

  17. Amino acid salt solutions for carbon dioxide capture

    OpenAIRE

    Majchrowicz, Magdalena Elzbieta

    2014-01-01

    Reactive absorption is a common process in the chemical industry and is used, among others, in the treatment of CO2 containing industrial gas streams. The current work was a part of a project with the aim to assess new reactive solvents based on amino acid salts for CO2 removal from industrial gas streams. Initially, a group of promising amino acid salts (taurine, sarcosine, L-proline, -alanine, 6-aminohexanoic acid and DL-methionine) was screened for their CO2 absorption kinetics, pKa value...

  18. Amino acids as corrosion inhibitors for copper in acidic medium: Experimental and theoretical study

    OpenAIRE

    Milošev Ingrid; Pavlinac Jasminka; Hodošček Milan; Lesar Antonija

    2013-01-01

    Experimental electrochemical methods combined with quantum chemical calculations and molecular dynamics simulations were used to investigate the possibility of use various amino acids as “green” corrosion inhibitors for copper in 0.5 M HCl solution. Among eleven amino acids studied, cysteine achieved the highest inhibitor effectiveness reaching 52% at 10 mM concentration. Other amino acids reached achieved effectiveness less than 25%, some of them even acte...

  19. Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

    Science.gov (United States)

    Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Bruckner, H.

    2010-01-01

    The presence of non-protein alpha-dialkyl-amino acids such as alpha-aminoisobutyric acid (alpha-A1B) and isovaline (Iva), which are relatively rare in the terrestrial biosphere, has long been used as an indication of the indigeneity of meteoritic amino acids, however, the discovery of alpha-AIB in peptides producers by a widespread group of filamentous fungi indicates the possibility of a terrestrial biotic source for the alpha-AIB observed in some meteorites. The alpha-AIB-containing peptides produced by these fungi are dubbed peptaibiotics. We measured the molecular distribution and stable carbon and nitrogen isotopic ratios for amino acids found in the total hydrolysates of four biologically synthesized peptaibiotics. We compared these aneasurenetts with those from the CM2 carbonaceous chondrite Murchison and from three Antarctic CR2 carbonaceous chondrites in order to understand the peptaibiotics as a potential source of meteoritic contamination.

  20. RESEARCH ON THE POLYCONDENSATION KINETICS OF ω-AMINO-ACIDS

    Institute of Scientific and Technical Information of China (English)

    WANG Baoren; SHI Manli; QIAN Chunqing

    1983-01-01

    In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%.It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids (monomers of the A-B type), and the controversial results that appeared in the literature may be cleared up by our experiments.

  1. Amino acid containing glass-ionomer cement for orthopedic applications

    Science.gov (United States)

    Wu, Wei

    Amino acid containing glass-ionomer cements were synthesized, formulated, and evaluated for orthopedic application. The formulation of different amino acid containing glass-ionomer bone cements was optimized, and conventional and resin-modified glass-ionomer bone cements were compared. Properties of interest included handling characteristics, physical and chemical properties, and mechanical strength of the bone cement. The study was based on the synthesis of different vinyl containing amino acids, different polyelectrolytes containing these amino acid residues, and different resin-modified polyelectrolytes, as well as formulation and evaluation of conventional and resin-modified glass-ionomer bone cements using these polyelectrolytes. Systematic preparation of polyelectrolytes and formulation of glass-ionomer bone cements were essential features of this work, since we anticipated that the mechanical properties of the glass-ionomer bone cements could be strongly affected by the nature of the polyelectrolytes and formulation. Mechanical properties were evaluated in a screw driven mechanical testing machine, and structure-property relationships were determined by scanning electron microscopic (SEM) observation of the fracture surface of the specimens. How the structure of polyelectrolytes, such as different amino acid residues, molecular weight, different modifying resin, and formulation of glass-ionomer bone cement, affected the mechanical properties was also studied.

  2. FLU, an amino acid substitution model for influenza proteins

    Directory of Open Access Journals (Sweden)

    Gascuel Olivier

    2010-04-01

    Full Text Available Abstract Background The amino acid substitution model is the core component of many protein analysis systems such as sequence similarity search, sequence alignment, and phylogenetic inference. Although several general amino acid substitution models have been estimated from large and diverse protein databases, they remain inappropriate for analyzing specific species, e.g., viruses. Emerging epidemics of influenza viruses raise the need for comprehensive studies of these dangerous viruses. We propose an influenza-specific amino acid substitution model to enhance the understanding of the evolution of influenza viruses. Results A maximum likelihood approach was applied to estimate an amino acid substitution model (FLU from ~113, 000 influenza protein sequences, consisting of ~20 million residues. FLU outperforms 14 widely used models in constructing maximum likelihood phylogenetic trees for the majority of influenza protein alignments. On average, FLU gains ~42 log likelihood points with an alignment of 300 sites. Moreover, topologies of trees constructed using FLU and other models are frequently different. FLU does indeed have an impact on likelihood improvement as well as tree topologies. It was implemented in PhyML and can be downloaded from ftp://ftp.sanger.ac.uk/pub/1000genomes/lsq/FLU or included in PhyML 3.0 server at http://www.atgc-montpellier.fr/phyml/. Conclusions FLU should be useful for any influenza protein analysis system which requires an accurate description of amino acid substitutions.

  3. Postnatal changes of plasma amino acids in suckling pigs.

    Science.gov (United States)

    Flynn, N E; Knabe, D A; Mallick, B K; Wu, G

    2000-09-01

    Amino acids, ammonia, urea, orotate, and nitrate plus nitrite (stable oxidation products of nitric oxide) were determined in plasma of 1- to 21-d-old suckling pigs. Jugular venous blood samples were obtained from pigs at 1, 3, 7, 14, and 21 d of age for analysis of plasma amino acids and metabolites by HPLC and enzymatic methods. Plasma concentrations of arginine and its immediate precursors (citrulline and ornithine) decreased (P Plasma concentrations of glutamine declined (P Plasma concentrations of branched-chain amino acids, threonine, and alanine decreased (P changes (P > 0.05) in plasma concentrations of other amino acids. Plasma concentrations of ammonia increased (P nitric oxide synthesis, our results of the decreased plasma concentrations of arginine and nitrate plus nitrite, as well as the increased plasma ammonia concentration, indicate a hitherto unrecognized deficiency of arginine in 7- to 21-d-old suckling pigs. Arginine is an essential amino acid for piglets and has a great potential to enhance neonatal growth; therefore, further studies are necessary to elucidate the mechanism responsible for arginine deficiency in sow-reared piglets and to identify hormonal and metabolic means for improving neonatal arginine nutrition and growth. PMID:10985412

  4. Chiral analysis of amino acids using electrochemical composite bienzyme biosensors.

    Science.gov (United States)

    Domínguez, R; Serra, B; Reviejo, A J; Pingarrón, J M

    2001-11-15

    The construction and performance of bienzyme amperometric composite biosensors for the selective determination of l- or d-amino acids is reported. D- or L-Amino acid oxidase, horseradish peroxidase, and the mediator ferrocene were coimmobilized by simple physical inclusion into the bulk of a graphite-70% Teflon electrode matrix. Working conditions including amino acid oxidase loading and pH were optimized. Studies on the repeatability of the amperometric response obtained at +0.00 V, with and without regeneration of the electrode surface by polishing, on the useful lifetime of one single biosensor and on the reproducibility in the fabrication of different biosensors illustrate the robustness of the bioelectrodes design. Calibration plots by both amperometry in stirred solutions and flow injection with amperometric detection were obtained for L-arginine, L-phenylalanine, L-leucine, L-methionine, L-tryptophan, D-leucine, D-methionine, D-serine, and D-valine. Differences in sensitivity were discussed in terms of the hydrophobicity of the substrate and of the electrode surface. The bienzyme composite electrode was applied to the determination of L- and D-amino acids in racemic samples, as well as to the estimation of the L-amino acids content in muscatel grapes. PMID:11700983

  5. The role of amino acids in improvement in salt tolerance of crop plants

    Directory of Open Access Journals (Sweden)

    Abd El-Samad H. M.

    2010-09-01

    Full Text Available The present work has been performed to study the growth and metabolic activities of maize and broad bean plants which are shown to have a degree of sensitivity to salinity and to determine the role of amino acids proline or phenylalanine in increasing the salt tolerance of theses plants. Dry mass, water content, leaf area and photosynthetic pigment of maize and broad bean plants decreased with increasing salinity. These changes were accompanied with a drop in the contents of soluble sugars, soluble proteins and amino acids. This was accompanied by a marked increase in the proline content. When maize and broad bean plants sprayed with proline or phenylalanine the opposite effect was occurred, saccharides as well as proteins progressively increased at all sanitization levels and proline concentration significantly declined. Salinity significantly increased the sodium content in both shoots and roots of maize and broad bean plants, while a decline in the accumulation of K+, Ca++, Mg++ and P was observed. Amino acids treatments markedlyaltered the selectivity of Na+, K+, Ca++ and P in both maize and broad bean plants. Spraying with any of either proline orphenylalanine restricted Na+ uptake and enhanced the uptake of K+, K+/Na+ ratio, Ca++ and P selectivity in maize and broad bean plants.

  6. Functional Exposed Amino Acids of BauA as Potential Immunogen Against Acinetobacter baumannii.

    Science.gov (United States)

    Sefid, Fatemeh; Rasooli, Iraj; Jahangiri, Abolfazl; Bazmara, Hadise

    2015-06-01

    Multidrug-resistant Acinetobacter baumannii is recognized to be among the most difficult antimicrobial-resistant gram negative bacilli to control and treat. One of the major challenges that the pathogenic bacteria face in their host is the scarcity of freely available iron. To survive under such conditions, bacteria express new proteins on their outer membrane and also secrete iron chelators called siderophores. Antibodies directed against these proteins associated with iron uptake exert a bacteriostatic or bactericidal effect against A. baumanii in vitro, by blocking siderophore mediated iron uptake pathways. Attempts should be made to discover peptides that could mimic protein epitopes and possess the same immunogenicity as the whole protein. Subsequently, theoretical methods for epitope prediction have been developed leading to synthesis of such peptides that are important for development of immunodiagnostic tests and vaccines. The present study was designed to in silico resolving the major obstacles in the control or in prevention of the diseases caused by A. baumannii. We exploited bioinformatic tools to better understand and characterize the Baumannii acinetobactin utilization structure of A. baumannii and select appropriate regions as effective B cell epitopes. In conclusion, amino acids 26-191 of cork domain and 321-635 of part of the barrel domain including L4-L9, were selected as vaccine candidates. These two regions contain functional exposed amino acids with higher score of B cell epitopes properties. Majority of amino acids are hydrophilic, flexible, accessible, and favorable for B cells from secondary structure point of view. PMID:25840681

  7. Uptake of palmitic acid by rabbit alveolar type II cells

    International Nuclear Information System (INIS)

    Alveolar type II cells require a source of palmitic acid for synthesis of dipalmitoyl phosphatidylcholine (DPPC), a major constituent of pulmonary surfactant. Previous studies indicated that maximal rates of DPPC synthesis are achieved only if exogenous palmitate is available to the type II cell. Little is known of the mechanisms by which fatty acids enter type II cells. To determine if uptake is mediated by a membrane carrier system, as described in other cell types, we examined the kinetics of palmitate uptake. Using freshly isolated rabbit type II cells, we demonstrated that radiolabeled palmitate uptake was maximal and linear for 45 s; after 1 min the apparent rate of uptake declined. The initial uptake phase was taken as a measure of cellular fatty acid influx because intracellular radiolabeled palmitate remained 80% nonesterified at this time but was 55% esterified by 2 min. Cellular influx of palmitate showed saturation kinetics with increasing concentration of nonalbumin bound palmitate. Michaelis constant was 52.6 nM, and maximum velocity was 152 pmol.10(6) cells-1.min-1. The hypothesis that saturable cellular influx of palmitate is likely linked to the previously identified membrane fatty acid binding protein (MFABP) was supported by Western-blot analysis of rat lung tissue with an antibody to MFABP that demonstrated the presence of this carrier protein in lung tissue. These data suggest that palmitate uptake by type II cells is saturable and may be mediated by a membrane-associated carrier as described in other cell types

  8. The Studies of the Reactions of 2, 4, 6-Triphenylpyrylium Tetrafluoroborate with Amino Acids

    Institute of Scientific and Technical Information of China (English)

    Shrong Shi LIN; Xian Jing KONG; Jing Yuan LIU; Cheng Yong LI

    2003-01-01

    The reactions of triphenylpyrylium salt 1 with various amino acids were explored andcompared. The reactions with most α-amino acids yielded decarboxylation products 2 viadecarboxylation. The reactions with glutamic acid, lysine and ACC (1-aminocyclopropyl-carboxylic acid) gave triphenylpyridine 8, dimer 9 and acid 5a-acc, respectively. The reactionswith β and γ-amino acids yielded triphenylpyridine by intramolecular elimination.

  9. THz time-domain spectroscopy of amino acids

    Institute of Scientific and Technical Information of China (English)

    WANG Weining; YUE Weiwei; YAN Haitao; ZHANG Cunlin; ZHAO Guozhong

    2005-01-01

    The optical characteristics of four kinds of amino acids (tyrosine, arginine, histidine and glutamine) filled with nitrogen at room temperature were studied by THz time-domain spectroscopy (THz-TDS). Well-resolved absorption and refractive spectrums between 0.1 and 2.8 THz were obtained based on the physical model for extracting the optical parameters of materials in THz range. The results not only fill up the spectra gap of amino acids in far-infrared range, supply data for amino acid molecular identification and conformation analysis, but also demonstrate significantly potential to promote the research and application of biological materials in bio-chemical and medical fields by THz-TDS.

  10. Protein evolution via amino acid and codon elimination

    DEFF Research Database (Denmark)

    Goltermann, Lise; Larsen, Marie Sofie Yoo; Banerjee, Rajat;

    2010-01-01

    a common buried residue, Phe, from the green fluorescent protein (GFP), while retaining activity. A GFP variant containing 11 Phe residues was used as starting scaffold to generate 10 separate variants in which each Phe was replaced individually (in one construct two adjacent Phe residues were changed......BACKGROUND: Global residue-specific amino acid mutagenesis can provide important biological insight and generate proteins with altered properties, but at the risk of protein misfolding. Further, targeted libraries are usually restricted to a handful of amino acids because there is an exponential...... correlation between the number of residues randomized and the size of the resulting ensemble. Using GFP as the model protein, we present a strategy, termed protein evolution via amino acid and codon elimination, through which simplified, native-like polypeptides encoded by a reduced genetic code were obtained...

  11. tRNAs: cellular barcodes for amino acids

    DEFF Research Database (Denmark)

    Banerjee, Rajat; Chen, Shawn; Dare, Kiley;

    2010-01-01

    The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has...... also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl-tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond...... translation, which together suggest that the role of tRNA is to deliver amino acids for a variety of processes that includes, but is not limited to, protein synthesis....

  12. Amino acid sequences of proteins from Leptospira serovar pomona

    Directory of Open Access Journals (Sweden)

    Alves Selmo F

    2000-01-01

    Full Text Available This report describes a partial amino acid sequences from three putative outer envelope proteins from Leptospira serovar pomona. In order to obtain internal fragments for protein sequencing, enzymatic and chemical digestion was performed. The enzyme clostripain was used to digest the proteins 32 and 45 kDa. In situ digestion of 40 kDa molecular weight protein was accomplished using cyanogen bromide. The 32 kDa protein generated two fragments, one of 21 kDa and another of 10 kDa that yielded five residues. A fragment of 24 kDa that yielded nineteen residues of amino acids was obtained from 45 kDa protein. A fragment with a molecular weight of 20 kDa, yielding a twenty amino acids sequence from the 40 kDa protein.

  13. Probing the Sophisticated Synergistic Allosteric Regulation of Aromatic Amino Acid Biosynthesis in Mycobacterium tuberculosis Using ᴅ-Amino Acids

    Science.gov (United States)

    Reichau, Sebastian; Blackmore, Nicola J.; Jiao, Wanting; Parker, Emily J.

    2016-01-01

    Chirality plays a major role in recognition and interaction of biologically important molecules. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of the shikimate pathway, which is responsible for the synthesis of aromatic amino acids in bacteria and plants, and a potential target for the development of antibiotics and herbicides. DAH7PS from Mycobacterium tuberculosis (MtuDAH7PS) displays an unprecedented complexity of allosteric regulation, with three interdependent allosteric binding sites and a ternary allosteric response to combinations of the aromatic amino acids l-Trp, l-Phe and l-Tyr. In order to further investigate the intricacies of this system and identify key residues in the allosteric network of MtuDAH7PS, we studied the interaction of MtuDAH7PS with aromatic amino acids that bear the non-natural d-configuration, and showed that the d-amino acids do not elicit an allosteric response. We investigated the binding mode of d-amino acids using X-ray crystallography, site directed mutagenesis and isothermal titration calorimetry. Key differences in the binding mode were identified: in the Phe site, a hydrogen bond between the amino group of the allosteric ligands to the side chain of Asn175 is not established due to the inverted configuration of the ligands. In the Trp site, d-Trp forms no interaction with the main chain carbonyl group of Thr240 and less favourable interactions with Asn237 when compared to the l-Trp binding mode. Investigation of the MtuDAH7PSN175A variant further supports the hypothesis that the lack of key interactions in the binding mode of the aromatic d-amino acids are responsible for the absence of an allosteric response, which gives further insight into which residues of MtuDAH7PS play a key role in the transduction of the allosteric signal. PMID:27128682

  14. Seasonal changes of exogenic amino acids concentration and kinetics of their assimilation in the water of lake Drukshiai - the cooler of Ignalina NPP in 1994

    International Nuclear Information System (INIS)

    Concentration of free and combined amino acids in the surface water of lake Drukshiai - the cooler of Ignalina NPP was determined. The direct connection between the concentration of free amino acids and domination of blue-green algae in planktocenosis was observed. Accordingly to kinetic indices of 14C - glutaminic acid uptake maximum assimilation rate and circulation time - lake Drukshiai may be ascribed to mezotrophic type with distinct areas of eutrophication. (author). 6 refs., 1 tab., 5 figs

  15. Hypertonic upregulation of amino acid transport system A in vascular smooth muscle cells.

    Science.gov (United States)

    Chen, J G; Klus, L R; Steenbergen, D K; Kempson, S A

    1994-08-01

    The A10 line of vascular smooth muscle cells has Na+ dependent transport systems for alanine, proline, and Pi, whereas uptake of leucine, myo-inositol and D-glucose is Na+ independent. When A10 cells were incubated for 4 h in medium made hypertonic by addition of sucrose, there was a marked increase in Na(+)-dependent transport of alanine and proline but no change in Na(+)-dependent Pi uptake or Na(+)-independent uptake of leucine and inositol. Intracellular alanine content was increased 61% by the hypertonic treatment. Other nonpenetrating solutes, such as cellobiose and mannitol, reproduced the effect of sucrose, but urea, a penetrating solute, did not. Studies with 2-(methylamino)-isobutyric acid revealed that the upregulation by hypertonicity involved only system A. Increases in alanine and proline uptake also occurred after incubating the cells in isotonic medium containing 0.1 mM ouabain, suggesting that an increase in intracellular Na+ may be part of the intracellular signal for upregulation of system A. Hypertonic upregulation of Na(+)-dependent alanine transport occurred also in primary cultures of vascular smooth muscle cells. The response was blocked by actinomycin D and cycloheximide, indicating that gene transcription and protein synthesis play important roles in the mechanism leading to increased alanine uptake. We conclude that vascular smooth muscle cells, during prolonged hypertonic stress, activate system A and accumulate specific neutral amino acids which may act as organic osmolytes to help maintain normal cell volume. PMID:8074188

  16. Biosynthesis of monoterpenoids in higher plants. The biosynthetic pathway leading to the monoterpenoids from amino acids with a carbon-skeleton similar to mevalonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tange, K. (Hiroshima Univ. (Japan). Faculty of Science)

    1981-09-01

    Radioisotopically labeled L-valine, DL-alanine, sodium acetate, and DL-mevalonic acid were incorporated into linalool by the intact plant of Cinnamomum camphora Sieb. var. linalooliferum Fujita and into geraniol and citronellol by that of Pelargonium roseum Bourbon. The uptake of leucine and valine resulted in the preferential location of the radioactivity on the 3,3-dimethylallyl pyrophosphate-derived moiety of these acyclic monoterpenoids, whereas the uptake of alanine resulted in the preferential location on the isopentenyl pyrophosphate-derived moiety, much as in the cases of mevalonic acid and sodium acetate. A biosynthetic pathway leading to the monoterpenoids from the amino acids is discussed.

  17. Solid state radiolysis of amino acids in an astrochemical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Franco, E-mail: franco.cataldo@fastwebnet.i [Istituto Nazionale di Astrofisica-Osservatorio Astrofisica di Catania, Via S. Sofia 78, 95123 Catania (Italy); Lupi Chemical Research, Via Casilina 1626/A, 00133 Rome (Italy); Angelini, Giancarlo [Istituto di Metodologie Chimiche, CNR, Via Salaria Km 29300, 00016 Monterotondo Stazione, Rome (Italy); Iglesias-Groth, Susana [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain); Manchado, Arturo [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain) and CSIC (Spain)

    2011-01-15

    The aliphatic amino acids L-alanine and L-leucine and the aromatic amino acids L-phenylalanine, L-tyrosine and L-tryptophan were irradiated in the solid state to a dose of 3.2 MGy. The degree of decomposition was measured by differential scanning calorimetry (DSC). Furthermore the degree of radioracemization was measured by optical rotatory dispersion (ORD) spectroscopy. From the DSC measurement a radiolysis rate constant k and the half life T{sub 1/2} for each amino acid have been determined and extrapolated to a dose of 14 MGy, which corresponds to the expected total dose delivered by the decay of radionuclides to the organic molecules present in comets and asteroids in 4.6x10{sup 9} years, the age of the Solar System. It is shown that all the amino acids studied can survive a radiation dose of 14 MGy although they are reduced to 1/4-1/5 of their original value they had at the beginning of the history of the Solar System. Consequently, the amount of alanine or leucine found today in the meteorites known as carbonaceous chondrites is just 1/4-1/5 of the amount originally present at the epoch of the formation of the Solar System 4.6x10{sup 9} years ago. Among the amino acids studied, tyrosine shows the highest radiation resistance while tryptophan does not combine its relatively high radiation resistance with an elevated level of radioracemization resistance. Apart from the exception of tryptophan, it is shown that the radiolysis rate constants k of all the amino acids studied are in reasonable agreement with the radioracemization rate constant k{sub rac}.

  18. Uptake of 2, 4-Dichlorophenoxyacetic acid by Pseudomonas fluorescens

    Science.gov (United States)

    Wedemeyer, G.A.

    1966-01-01

    WEDEMEYER, GARY (Fish-Pesticide Research Laboratory, Denver, Colo.). Uptake of 2,4-dichlorophenoxyacetic acid by Pseudomonas fluorescens. Appl. Microbiol. 14:486-491. 1966.-Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “nonmetabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carriermediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranylion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

  19. Preparation of 4-amino-2,4-dioxobutanoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

    2016-03-22

    A process for synthesizing 4-amino-2,4-dioxobutanoic acid involves reacting diethyl oxalate with an alkoxide in ethanol to form a reaction mixture, and afterward adding ethyl cyanoacetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl 2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl 2-cyano-3-hydroxy-butenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with an aqueous hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoic acid.

  20. Transport of aromatic amino acids by Brevibacterium linens.

    OpenAIRE

    Boyaval, P; Moreira, E; Desmazeaud, M. J.

    1983-01-01

    Whole metabolizing Brevibacterium linens cells were used to study the transport of aromatic amino acids. Kinetic results followed the Michaelis-Menten equation with apparent Km values for phenylalanine, tyrosine, and tryptophan of 24, 3.5, and 1.8 microM. Transport of these amino acids was optimum at pH 7.5 and 25 degrees C for phenylalanine and pH 8.0 and 35 degrees C for tyrosine and tryptophan. Crossed inhibitions were all noncompetitive. The only marked stereospecificity was for the L for...

  1. Evidence for transport intermediates in aromatic amino acid synthesis of non-green tissues

    International Nuclear Information System (INIS)

    Quinate (QA) is the predominant pre-aromatic compound formed at high rates in leaves of many plants at the early vegetation stage and transported through the phloem. The transfer of 3-dehydroquinate, 3-dehydroshikimate and (SkA) across the plastidial membranes has been evidenced. The question was whether the rate of QA uptake is comparable to that of the 3 SkA-pathway intermediates. To demonstrate this, /U-14C/QA and /U-14C/SkA were applied to Brassica rapa roots. Both compounds were uptaken at considerable rates and incorporated into aromatic amino acids (Phe + Tyr + Trp formation, in nmol/g fresh wt x h: applying 145 μmol QA: 21.2; applying 156 μmol Ska: 31.8). Thus, QA is a possible candidate for transport into non-green tissues for aromatic amino acid synthesis

  2. Evidence for transport intermediates in aromatic amino acid synthesis of non-green tissues

    Energy Technology Data Exchange (ETDEWEB)

    Leuschner, C.; Schultz, G. (Botanisches Institut, Hannover (West Germany))

    1990-05-01

    Quinate (QA) is the predominant pre-aromatic compound formed at high rates in leaves of many plants at the early vegetation stage and transported through the phloem. The transfer of 3-dehydroquinate, 3-dehydroshikimate and (SkA) across the plastidial membranes has been evidenced. The question was whether the rate of QA uptake is comparable to that of the 3 SkA-pathway intermediates. To demonstrate this, /U-{sup 14}C/QA and /U-{sup 14}C/SkA were applied to Brassica rapa roots. Both compounds were uptaken at considerable rates and incorporated into aromatic amino acids (Phe + Tyr + Trp formation, in nmol/g fresh wt x h: applying 145 {mu}mol QA: 21.2; applying 156 {mu}mol Ska: 31.8). Thus, QA is a possible candidate for transport into non-green tissues for aromatic amino acid synthesis.

  3. Genetic analysis of amino acid content in wheat grain

    Indian Academy of Sciences (India)

    Xiaoling Jiang; Peng Wu; Jichun Tian

    2014-08-01

    Complete diallel crosses with five parents of common wheat (Triticum aestivum L.) were conducted to analyse inheritance of 17 amino acid contents by using the genetic model including seed, cytoplasmic, maternal and environment interaction effects on quantitative traits of seeds in cereal crops. The results showed that inheritance of 17 amino acid contents, except tyrosine, was controlled by several genetic systems including seed, cytoplasmic, and maternal effects, and by significant gene × environment interaction effects. Seed-direct additive and maternal effects constituted a major part of genetic effects for lysine, tyrosine, arginine, methionine, and glutamic acid content. Seed-direct additive effect formed main part in inheritance of isoleucine and serine contents. Threonine content was mainly governed by maternal additive effect. The other nine amino acid contents were almost entirely controlled by dominance effects. High general heritability of tyrosine (36.3%), arginine (45.8%), lysine (24.7%) and threonine (21.4%) contents, revealed that it could be effective to improve them by direct selection in progenies from appropriate crosses. Interaction heritability for phenylalanine, proline, and histidine content, which was 36.1%, 39.5% and 25.7%, respectively, was higher than for the other amino acids.

  4. Fission yeast arrestin-related trafficking adaptor, Arn1/Any1, is ubiquitinated by Pub1 E3 ligase and regulates endocytosis of Cat1 amino acid transporter

    Directory of Open Access Journals (Sweden)

    Akio Nakashima

    2014-05-01

    Full Text Available The Tsc1–Tsc2 complex homologous to human tuberous sclerosis complex proteins governs amino acid uptake by regulating the expression and intracellular distribution of amino acid transporters in Schizosaccharomyces pombe. Here, we performed a genetic screening for molecules that are involved in amino acid uptake and found Arn1 (also known as Any1. Arn1 is homologous to ART1, an arrestin-related trafficking adaptor (ART in Saccharomyces cerevisiae, and contains a conserved arrestin motif, a ubiquitination site, and two PY motifs. Overexpression of arn1+ confers canavanine resistance on cells, whereas its disruption causes hypersensitivity to canavanine. We also show that Arn1 regulates endocytosis of the Cat1 amino acid transporter. Furthermore, deletion of arn1+ suppresses a defect of amino acid uptake and the aberrant Cat1 localization in tsc2Δ. Arn1 interacts with and is ubiquitinated by the Pub1 ubiquitin ligase, which is necessary to regulate Cat1 endocytosis. Cat1 undergoes ubiquitinations on lysine residues within the N-terminus, which are mediated, in part, by Arn1 to determine Cat1 localization. Correctively, Arn1 is an ART in S. pombe and contributes to amino acid uptake through regulating Cat1 endocytosis in which Tsc2 is involved.

  5. Transport and signaling via the amino acid binding site of the yeast Gap1 amino acid transceptor.

    Science.gov (United States)

    Van Zeebroeck, Griet; Bonini, Beatriz Monge; Versele, Matthias; Thevelein, Johan M

    2009-01-01

    Transporter-related nutrient sensors, called transceptors, mediate nutrient activation of signaling pathways through the plasma membrane. The mechanism of action of transporting and nontransporting transceptors is unknown. We have screened 319 amino acid analogs to identify compounds that act on Gap1, a transporting amino acid transceptor in yeast that triggers activation of the protein kinase A pathway. We identified competitive and noncompetitive inhibitors of transport, either with or without agonist action for signaling, including nontransported agonists. Using substituted cysteine accessibility method (SCAM) analysis, we identified Ser388 and Val389 as being exposed into the amino acid binding site, and we show that agonist action for signaling uses the same binding site as used for transport. Our results provide the first insight, to our knowledge, into the mechanism of action of transceptors. They indicate that signaling requires a ligand-induced specific conformational change that may be part of but does not require the complete transport cycle. PMID:19060912

  6. System a amino acid transport-targeted brain and systemic tumor PET imaging agents 2-amino-3-[18 F]fluoro-2-methylpropanoic acid and 3-[18 F]fluoro-2-methyl-2-(methylamino)propanoic acid

    International Nuclear Information System (INIS)

    Introduction: Amino acid based radiotracers target tumor cells through increased uptake by membrane-associated amino acid transport (AAT) systems. In the present study, four structurally related non-natural 18 F-labeled amino acids, (R)- and (S)-[18 F]FAMP 1 and (R)- and (S)-[18 F]MeFAMP 2 have been prepared and evaluated in vitro and in vivo for their potential utility in brain and systemic tumor imaging based upon primarily system A transport with positron emission tomography (PET). Methods: The transport of enantiomers of [18 F]FAMP 1 and [18 F]MeFAMP 2 was measured through in vitro uptake assays in human derived cancer cells including A549 (lung), DU145 (prostate), SKOV3 (ovary), MDA MB468 (breast) and U87 (brain) in the presence and absence of amino acid transporter inhibitors. The in vivo biodistribution of these tracers was evaluated using tumor mice xenografts at 15, 30, 60 and 120 min post injection. Results: All four tracers showed moderate to high levels of uptake (1–9%ID/5 × 105 cells) by the cancer cell lines tested in vitro. AAT cell inhibition assays demonstrated that (R)-[18 F]1 and (S)-[18 F]1 entered these tumor cells via mixed AATs, likely but not limited to system A and system L. In contrast, (R)-[18 F]2 and (S)-[18 F]2 showed high selectivity for system A AAT. Similar to the results of in vitro cell studies, the tumor uptake of all four tracers was good to high and persisted over the 2 hours time course of in vivo studies. The accumulation of these tracers was higher in tumor than most normal tissues including blood, brain, muscle, bone, heart, and lung, and the tracers with the highest in vitro selectivity for system A AAT generally demonstrated the best tumor imaging properties. Higher uptake of these tracers was observed in the pancreas, kidney and spleen compared to tumors. Conclusions: These preclinical studies demonstrate good imaging properties in a wide range of tumors for all four amino acids evaluated with (R)-[18 F]2 having the

  7. Synthesis of novel {sup 68}Ga-labeled amino acid derivatives for positron emission tomography of cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Dinesh [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Jeong, Jae Min, E-mail: jmjng@snu.ac.k [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Ju, Chang Hwan [Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul (Korea, Republic of); Lee, Yun-Sang [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Jeong, Seo Young [Department of Life and Nanopharmaceutical Sciences, Graduate School, Kyung Hee University, Seoul (Korea, Republic of); Choi, Jae Yeon; Yang, Bo Yeun [Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Department of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of)

    2010-11-15

    Objectives: We developed amino acid derivatives of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) and 1,4,7,10-tetraazacyclododecane-1,4,7,-triacetic acid (DO3A) that can be labeled with {sup 68}Ga, and we investigated their basic biological properties. Materials and methods: Alanine derivatives of DO2A and DO3A were synthesized by regiospecific nucleophilic attack of DO2tBu and DO3tBu on the {beta}-position of Boc-L-serine-{beta}-lactone, followed by acid hydrolysis. Also, homoalanine derivatives were synthesized by reacting with the protected bromo derivative of homoalanine, which was synthesized from N-Cbz-L-homoserine lactone. Further catalytic reduction and acid cleavage of protected groups resulted in the required products. All derivatives were labeled with {sup 68}Ga. Cell uptake assays were carried out in Hep3B (human hepatoma) and U87MG (human glioma) cell lines at 37{sup o}C. Positron emission tomography (PET) imaging studies were performed using balb/c mice xenografted with CT-26 (mouse colon cancer). Results: All compounds were labeled with >97% efficiency. According to in vitro studies, the labeled amino acid derivatives showed significantly greater uptakes than the control ({sup 68}Ga 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) in cancer cells. Small animal PET images for labeled compounds showed high tumor uptake, as well as kidney and bladder uptakes, at 30 min postinjection. {sup 68}Ga-DO3A-homoalanine showed the highest standardized uptake value ratio (3.9{+-}0.3), followed by {sup 68}Ga-DO2A-alanine (3.1{+-}0.2), {sup 68}Ga-DO3A-alanine (2.8{+-}0.2) and {sup 68}Ga-DO2A-homoalanine (2.3{+-}0.2). Conclusion: These derivatives were found to have high labeling efficiencies, high stabilities, high tumor cell uptakes, high tumor/nontumor xenograft uptakes and low nonspecific uptake in normal organs, except for the kidneys. However, the uptake mechanism of these derivatives remains unclear, and uptake via specific amino acid

  8. Preparation of 4-amino-2,4-dioxobutanoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

    2016-03-22

    A process for synthesizing 4-amino-2,4-dioxobutanoate involves reacting a dialkyl oxalate with an alkoxide in ethanol to form a reaction mixture, and afterward adding an alkyl cyano acetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl 2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl 2-cyano-3-hydroxy-butenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with an aqueous hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoate. The 4-amino-2,4-dioxobutanoate may be acidified into 4-amino-2,4-dioxobutanoic acid.

  9. Gastroprotective effect and cytotoxicity of labdeneamides with amino acids.

    Science.gov (United States)

    Schmeda-Hirschmann, Guillermo; Rodríguez, Jaime A; Theoduloz, Cristina; Valderrama, Jaime A

    2011-03-01

    Semisynthetic aromatic amides from ARAUCARIA ARAUCANA diterpene acids have been shown to display a relevant gastroprotective effect with low cytotoxicity. The aim of this work was to assess the gastroprotective effect of amino acid amides from imbricatolic acid and its 8(9)-en isomer in the ethanol/HCl-induced gastric lesions model in mice as well as to determine the cytotoxicity of the obtained compounds on the following human cell lines: normal lung fibroblasts (MRC-5), gastric adenocarcinoma (AGS), and liver hepatocellular carcinoma (Hep G2). The diterpenes 15-acetoxyimbricatolic acid, its 8(9)-en isomer, 15-hydroxyimbricatolic acid, and the 8(9)-en derivative, bearing a COOH function at C-19, were used as starting compounds. New amides with C-protected amino acids were prepared. The study reports the effect of a single oral administration of either compound 50 min before the induction of gastric lesions by ethanol/HCl. Some 20 amino acid monoamides were obtained. Dose-response experiments on the glycyl derivatives showed that at a single oral dose of 100 mg/kg, the compounds presented an effect comparable to the reference drug lansoprazole at 20 mg/kg and at 50 mg/kg reduced gastric lesions by about 50%. All derivatives obtained in amounts > 30 mg were compared at a single oral dose of 50 mg/kg. The best gastroprotective effect was observed for the exomethylene derivatives bearing a valine residue at C-19 either with an acetoxy or free hydroxy group at C-15. The tryptophanyl derivative from the acetate belonging to the 8,9-en series presented selective cytotoxicity against hepatocytes. The glycyl amide of 15-acetoxyimbricatolic acid was the most cytotoxic and less selective compound with IC₅₀ values between 47 and 103 µM for the studied cell lines. This is the first report on the obtention of semisynthetic amino acid amides from labdane diterpenes. PMID:20862639

  10. Antioxidant effects of sulfur-containing amino acids.

    Science.gov (United States)

    Atmaca, Gulizar

    2004-10-31

    Sulfur is an essential element for the entire biological kingdom because of its incorporation into amino acids, proteins and other biomolecules. Sulfur atoms are also important in the iron-containing flavoenzymes. Unlike humans, plants can use inorganic sulfur to synthesize sulfur-containing amino acids. Therefore, plants are an important source of sulfur for humans. Sulfur-containing compounds are found in all body cells and are indispensable for life. Some of sulfur-containing antioxidant compounds are, cysteine, methionine, taurine, glutathione, lipoic acid, mercaptopropionylglycine, N-acetylcysteine, and the three major organosulfur compounds of garlic oil, diallylsulfide, diallyldisulfide and diallyltrisulfide. In a comparison of the structure-function relationship among these sulfur-containing antioxidant compounds, dihydrolipoic acid (the reduced form of LA) is the most effective antioxidant. Dihydrolipoic acid contains two sulfhydryl groups and can undergo further oxidation reaction to form lipoic acid. The antioxidative activities of sulfur-containing compounds follow a general trend, the more highly reduced forms are stronger antioxidants and the number of sulfur atoms determine, at least in part, their modulatory activites on the glutathione related antioxidant enzymes. In this article, the antioxidant effects and the antioxidative activities, of sulfur-containing amino acids, are reviewed. In addition, the general antioxidant effects and the structure-function relationship of some sulfur-containing compounds are also reviewed. PMID:15515186

  11. A comparative proteomic analysis of the simple amino acid repeat distributions in Plasmodia reveals lineage specific amino acid selection.

    Directory of Open Access Journals (Sweden)

    Andrew R Dalby

    Full Text Available BACKGROUND: Microsatellites have been used extensively in the field of comparative genomics. By studying microsatellites in coding regions we have a simple model of how genotypic changes undergo selection as they are directly expressed in the phenotype as altered proteins. The simplest of these tandem repeats in coding regions are the tri-nucleotide repeats which produce a repeat of a single amino acid when translated into proteins. Tri-nucleotide repeats are often disease associated, and are also known to be unstable to both expansion and contraction. This makes them sensitive markers for studying proteome evolution, in closely related species. RESULTS: The evolutionary history of the family of malarial causing parasites Plasmodia is complex because of the life-cycle of the organism, where it interacts with a number of different hosts and goes through a series of tissue specific stages. This study shows that the divergence between the primate and rodent malarial parasites has resulted in a lineage specific change in the simple amino acid repeat distribution that is correlated to A-T content. The paper also shows that this altered use of amino acids in SAARs is consistent with the repeat distributions being under selective pressure. CONCLUSIONS: The study shows that simple amino acid repeat distributions can be used to group related species and to examine their phylogenetic relationships. This study also shows that an outgroup species with a similar A-T content can be distinguished based only on the amino acid usage in repeats, and suggest that this might be a useful feature for proteome clustering. The lineage specific use of amino acids in repeat regions suggests that comparative studies of SAAR distributions between proteomes gives an insight into the mechanisms of expansion and the selective pressures acting on the organism.

  12. Analysis of Peptides and Conjugates by Amino Acid Analysis

    DEFF Research Database (Denmark)

    Højrup, Peter

    2015-01-01

    Amino acid analysis is a highly accurate method for characterization of the composition of synthetic peptides. Together with mass spectrometry, it gives a reliable control of peptide quality and quantity before conjugation and immunization.Peptides are hydrolyzed, preferably in gas phase, with 6 M...... HCl at 110 °C for 20-24 h and the resulting amino acids analyzed by ion-exchange chromatography with post-column ninhydrin derivatization. Depending on the hydrolysis conditions, tryptophan is destroyed, and cysteine also, unless derivatized, and the amides, glutamine and asparagine, are deamidated to...... glutamic acid and aspartic acid, respectively. Three different ways of calculating results are suggested, and taking the above limitations into account, a quantitation better than 5 % can usually be obtained....

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

    Science.gov (United States)

    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.

  14. Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids

    Science.gov (United States)

    Helinck, Sandra; Le Bars, Dominique; Moreau, Daniel; Yvon, Mireille

    2004-01-01

    Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus to produce aroma compounds from three amino acids, leucine, phenylalanine, and methionine, under mid-pH conditions of cheese ripening (pH 5.5), and we investigated the catabolic pathways used by these bacteria. In the three lactic acid bacterial species, amino acid catabolism was initiated by a transamination step, which requires the presence of an α-keto acid such as α-ketoglutarate (α-KG) as the amino group acceptor, and produced α-keto acids. Only S. thermophilus exhibited glutamate dehydrogenase activity, which produces α-KG from glutamate, and consequently only S. thermophilus was capable of catabolizing amino acids in the reaction medium without α-KG addition. In the presence of α-KG, lactobacilli produced much more varied aroma compounds such as acids, aldehydes, and alcohols than S. thermophilus, which mainly produced α-keto acids and a small amount of hydroxy acids and acids. L. helveticus mainly produced acids from phenylalanine and leucine, while L. delbrueckii subsp. lactis produced larger amounts of alcohols and/or aldehydes. Formation of aldehydes, alcohols, and acids from α-keto acids by L. delbrueckii subsp. lactis mainly results from the action of an α-keto acid decarboxylase, which produces aldehydes that are then oxidized or reduced to acids or alcohols. In contrast, the enzyme involved in the α-keto acid conversion to acids in L. helveticus and S. thermophilus is an α-keto acid dehydrogenase that produces acyl coenzymes A. PMID:15240255

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

    Directory of Open Access Journals (Sweden)

    Xiaochuang Cao

    Full Text Available 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

  16. High- and low-affinity binding of S-citalopram to the human serotonin transporter mutated at 20 putatively important amino acid positions

    DEFF Research Database (Denmark)

    Plenge, Per; Wiborg, Ove

    2005-01-01

    uptake inhibitors and serotonin (5-HT) have been found on SERT. At one site, uptake inhibitors bind with high-affinity to SERT, thereby blocking the uptake of 5-HT. The other site is a low-affinity allosteric site, which influences the dissociation of uptake inhibitors, such as imipramine, paroxetine......, and citalopram from the first site, when occupied by 5-HT and a few uptake inhibitors like paroxetine and citalopram. In this study, the connection between the high-affinity binding site and the allosteric affinity-modulating site was investigated by introducing 20 single amino acid substitutions into...

  17. Yeast colony development and ammonia signalling: Role of amino acids

    Czech Academy of Sciences Publication Activity Database

    Begany, Markéta; Váchová, Libuše; Palková, Z.

    Vienna : Springer, 2006, A109-A109. [International Symposium on Microbial Ecology – ISME-11 /11./. Vienna (AT), 20.08.2006-25.08.2006] R&D Projects: GA ČR GA204/05/0294; GA MŠk(CZ) LC531 Institutional research plan: CEZ:AV0Z50200510 Keywords : yeast colony * amino acid Subject RIV: EE - Microbiology, Virology

  18. Branched-chain amino acids for people with hepatic encephalopathy

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Dam, Gitte; Les, Iñigo;

    2015-01-01

    -chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy. OBJECTIVES: To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy. SEARCH METHODS: We identified trials through...

  19. Analysis of Saccharides by the Addition of Amino Acids

    Science.gov (United States)

    Ozdemir, Abdil; Lin, Jung-Lee; Gillig, Kent J.; Gulfen, Mustafa; Chen, Chung-Hsuan

    2016-06-01

    In this work, we present the detection sensitivity improvement of electrospray ionization (ESI) mass spectrometry of neutral saccharides in a positive ion mode by the addition of various amino acids. Saccharides of a broad molecular weight range were chosen as the model compounds in the present study. Saccharides provide strong noncovalent interactions with amino acids, and the complex formation enhances the signal intensity and simplifies the mass spectra of saccharides. Polysaccharides provide a polymer-like ESI spectrum with a basic subunit difference between multiply charged chains. The protonated spectra of saccharides are not well identified because of different charge state distributions produced by the same molecules. Depending on the solvent used and other ions or molecules present in the solution, noncovalent interactions with saccharides may occur. These interactions are affected by the addition of amino acids. Amino acids with polar side groups show a strong tendency to interact with saccharides. In particular, serine shows a high tendency to interact with saccharides and significantly improves the detection sensitivity of saccharide compounds.

  20. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO2 with ubiquitous amino acids present in natural waters.

  1. Gas-Phase IR Spectroscopy of Deprotonated Amino Acids

    NARCIS (Netherlands)

    Oomens, J.; Steill, J. D.; Redlich, B.

    2009-01-01

    Gas-phase infrared multiple photon dissociation (IRMPD) spectra have been recorded for the conjugate bases of a series of amino acids (Asp, Cys, Glu, Phe, Set, Trp, Tyr). The spectra are dominated by strong symmetric and antisymmetric carboxylate stretching modes around 1300 and 1600 cm(-1), respect

  2. Force field modeling of amino acid conformational energies

    Czech Academy of Sciences Publication Activity Database

    Kaminský, Jakub; Jensen, F.

    2007-01-01

    Roč. 3, č. 5 (2007), s. 1774-1788. ISSN 1549-9618 R&D Projects: GA AV ČR IAA400550702 Institutional research plan: CEZ:AV0Z40550506 Keywords : amino acids * modeling * MP2 * DFT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.308, year: 2007

  3. Association Analysis of the Amino Acid Contents in Rice

    Institute of Scientific and Technical Information of China (English)

    Weiguo Zhao; Eun-Jin Park; Jong-Wook Chung; Yong-Jin Park; III-Min Chung; Joung-Kuk Ahn; Gwang-Ho Kim

    2009-01-01

    The main objective of the present study was to identify simple sequence repeat (SSR) markers associated with the amino acid content of rice (Oryza sativa L.). SSR markers were selected by prescreening for the relationship to amino acid content. Eighty-four rice landrace accessions from Korea were evaluated for 16 kinds of amino acids in brown rice and genotyped with 25 SSR markers. Analysis of population structure revealed four subgroups in the population. Linkage disequilibrium (LD) patterns and distributions are of fundamental importance for genome-wide mapping associations. The mean r2 value for all intrachromosomal loci pairs was 0.033. LD between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). A total of 42 marker-trait associations with amino acids (P < 0.05) were identified using 15 different SSR markers covering three chromosomes and explaining more than 40% of the total variation. These results suggest that association analysis In rice is a viable alternative to quantitative trait loci mapping and should help rice breeders develop strategies for improving rice quality.

  4. Amino acids in root exudates of Ambrosia artemisiifolia

    Czech Academy of Sciences Publication Activity Database

    Hohnová, Barbora; Moravcová, Dana; Figala, J.; Lvončík, S.; Lojková, Lea; Formánek, P.

    2015-01-01

    Roč. 47, - (2015), s. 1691-1691. ISSN 0939-4451. [International Congress on Amino Acids, Peptides and Proteins /14./. 03.08.2015-07.08.2015, Vienna] Institutional support: RVO:68081715 Keywords : PHWE * GC-MS * SDS-PAGE Subject RIV: CB - Analytical Chemistry, Separation

  5. Engineering Dehydrated Amino Acid Residues in the Antimicrobial Peptide Nisin

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Rollema, Harry S.; Yap, Wyanda M.G.J.; Boot, Hein J.; Siezen, Roland J.; Vos, Willem M. de

    1992-01-01

    The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role i

  6. On the evolution of the standard amino-acid alphabet

    OpenAIRE

    Lu, Yi; Freeland, Stephen

    2006-01-01

    Although one standard amino-acid 'alphabet' is used by most organisms on Earth, the evolutionary cause(s) and significance of this alphabet remain elusive. Fresh insights into the origin of the alphabet are now emerging from disciplines as diverse as astrobiology, biochemical engineering and bioinformatics.

  7. One-Pot Synthesis of N-Phosphoryl Amino Acids

    Institute of Scientific and Technical Information of China (English)

    GUO Xin; FU Hua; LIN Chang-Xue; ZHAO Yu-Fen

    2003-01-01

    @@ Phosphoramidates have been considered as an important class of rationally designed therapeutics especially asoligonucleotide analogs employed as antisene and antigene agents. [1] N-Phosphoryl amino acids are of biological andpharmaceutical interest, [2] and can be used as the building blocks in synthesis of polypeptides. [3

  8. CSF Amino Acids, Pterins and Mechanism of the Ketogenic Diet

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2015-11-01

    Full Text Available Investigators from Hospital Sant Joan de Deu, Barcelona, Spain, studied the relationship between the etiology of refractory childhood epilepsy, CSF neurotransmitters, pterins, and amino acids, and response to a ketogenic diet in 60 patients with refractory epilepsy, 83% focal and 52% idiopathic.

  9. Single amino acid supplementation in aminoacidopathies : a systematic review

    NARCIS (Netherlands)

    van Vliet, Danique; Derks, Terry G. J.; van Rijn, Margreet; de Groot, Martijn J.; MacDonald, Anita; Heiner-Fokkema, M. Rebecca; van Spronsen, Francjan J.

    2014-01-01

    Aminoacidopathies are a group of rare and diverse disorders, caused by the deficiency of an enzyme or transporter involved in amino acid metabolism. For most aminoacidopathies, dietary management is the mainstay of treatment. Such treatment includes severe natural protein restriction, combined with

  10. Polarized Raman spectra and intensities of aliphatic amino acids

    Science.gov (United States)

    Himmler, Hans J.; Eysel, Hans H.

    1989-01-01

    Raman spectra of aliphatic α- L-amino acids, glycine, alanine, and valine were re-investigated both in aqueous solution and deuterium oxide solution. The spectra were taken of the zwitterionic and of the completely deprotonated form of the amino acids. Spectra of leucine and isoleucine were studied in water at the isoelectric point. Spectra were recorded both with parallel and perpendicular polarization and the isotropic and anisotropic scattering components were isolated. The integrated intensities of CH stretch, CC stretch and carboxylate bend vibrations are discussed. Linear relations between the number of CC and CH bonds and the total scattered intensity in the appropriate spectral regions are observed. The sum over the carboxylate modes shows characteristic intensities for the first three members of the aliphatic amino acids. An increase of isotropic scattering of ϱ co 2 near 510 cm -1 with increasing chain length of the amino acid (or with increasing concentration) is interpreted as the result of micelle formation.

  11. Amino acid salt solutions for carbon dioxide capture

    NARCIS (Netherlands)

    Majchrowicz, Magdalena Elzbieta

    2014-01-01

    Reactive absorption is a common process in the chemical industry and is used, among others, in the treatment of CO2 containing industrial gas streams. The current work was a part of a project with the aim to assess new reactive solvents based on amino acid salts for CO2 removal from industrial gas s

  12. Identification of essential amino acids in the Streptococcus mutans glucosyltransferases.

    Science.gov (United States)

    Tsumori, H; Minami, T; Kuramitsu, H K

    1997-01-01

    A comparison of the amino acid sequences of the glucosyltransferases (GTFs) of mutans streptococci with those from the alpha-amylase family of enzymes revealed a number of conserved amino acid positions which have been implicated as essential in catalysis. Utilizing a site-directed mutagenesis approach with the GTF-I enzyme of Streptococcus mutans GS-5, we identified three of these conserved amino acid positions, Asp413, Trp491, and His561, as being important in enzymatic activity. Mutagenesis of Asp413 to Thr resulted in a GTF which expressed only about 12% of the wild-type activity. In contrast, mutagenesis of Asp411 did not inhibit enzyme activity. In addition, the D413T mutant was less stable than was the parental enzyme when expressed in Escherichia coli. Moreover, conversion of Trp491 or His561 to either Gly or Ala resulted in enzymes devoid of GTF activity, indicating the essential nature of these two amino acids for activity. Furthermore, mutagenesis of the four Tyr residues present at positions 169 to 172 which are part of a subdomain with homology to the direct repeating sequences present in the glucan-binding domain of the GTFs had little overall effect on enzymatic activity, although the glucan products appeared to be less adhesive. These results are discussed relative to the mechanisms of catalysis proposed for the GTFs and related enzymes. PMID:9171379

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

    Science.gov (United States)

    ... features of aromatic L-amino acid decarboxylase deficiency. Neurology. 2010 Jul 6;75(1):64-71. doi: ... WNL.0b013e3181e620ae. Epub 2010 May 26. Erratum in: Neurology. 2010 Aug 10;75(6):576. Dosage error ...

  14. Amino acid peroxyl radicals. Formation and reaction with ascorbate

    International Nuclear Information System (INIS)

    Complete text of publication follows. Proteins are significant targets for partly reduced oxygen species in vivo. This results in random formation of radicals on the amino acid residues (AA·) of the protein, which in turn, in the presence of oxygen, can yield the corresponding peroxyl radicals (AAOO·). Both radical types can cause further biological damage. We studied the N-acetylamide derivatives of the amino acids glycine, alanine and proline as models of these residues in proteins. We generated the amino acid radicals specifically by reaction with hydroxyl radicals produced in solutions irradiated with 2 MeV electrons in the presence of N2O. In the absence of oxygen the amino acid radicals decayed with rate constants in the narrow range (0.9-1.3) x 109 M-1s-1, while in the presence of oxygen they were converted very rapidly to the corresponding peroxyl radicals with rate constants that vary between 6.3 x 108 and 5.5 x 109 M-1s-1, depending on the amino acid. The corresponding N-acetylated amino acids were also studied and showed similar behaviour but with slightly smaller rate constants. Antioxidants are able to repair tyrosyl and tryptophanyl radicals in various proteins in vitro. For ascorbate, the principal endogenous biological antioxidant, we have measured rate constants in the range 105-108 M-1s-1. The peroxyl radicals of all amino acids studied here were reduced by oxidizing ascorbate to the ascorbyl radical. The reaction was followed at 360 nm, where ascorbyl radical has an absorption coefficient of 3300 M-1cm-1, and the derived rate constants were all close to 107 M-1s-1. However, the spontaneous decay of peroxyl radicals is also fast and competes with the reaction with ascorbate. It is to be stressed that reaction of AAOO· and ascorbate gives rise to hydroperoxides (AAOOH) that are also reactive molecules. Our study suggests that reaction with protein radicals may be responsible for the ascorbate loss reported in organisms exposed to oxidative

  15. Transport mechanisms of trans-1-amino-3-fluoro[1-14C]cyclobutanecarboxylic acid in prostate cancer cells

    International Nuclear Information System (INIS)

    Introduction: We investigated the mechanisms of trans-1-amino-3-fluoro[1-14C]cyclobutanecarboxylic acid (anti-[14C]FACBC) transport by human-derived prostate cancer (PCa) cells and normal human prostatic epithelial cells (PrECs). Methods: Using PCa cells (DU145, PC-3, LNCaP) and PrECs, we performed the following in vitro experiments: time-course, kinetics, competitive inhibition by synthetic/naturally occurring amino acids (AAs), exchange transport with synthetic/naturally occurring AAs and pH-dependency of anti-[14C]FACBC uptake. We also examined the amino acid transporter (AAT) expression using flow cytometry. Results: The uptake of anti-[14C]FACBC by LNCaP and DU145 cells was higher than that by PC-3 and PrECs. The Km values for anti-[14C]FACBC were 64.4 and 191.7 μmol/L in the DU145 cells and PrECs, respectively. Total levels of anti-[14C]FACBC uptake were positively correlated with the expression level of system ASC in PCa cells. The contributions of Na+-dependent AATs to anti-[14C]FACBC uptake were greater than those of Na+-independent AATs, especially in PCa cells. In the presence of Na+, glutamine and serine showed the strongest inhibitory effect against anti-[14C]FACBC uptake, suggesting that system ASC, especially ASCT2, is an important AAT for anti-[14C]FACBC. In contrast, phenylalanine and 2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid, but not N-ethylmaleimide, almost completely inhibited the anti-[14C]FACBC uptake in the absence of Na+, indicating the contribution of LAT1. In the exchange transport experiments, glutamine showed the strongest transstimulation of intracellular anti-[14C]FACBC efflux in DU145 cells. Furthermore, the contributions of Na+-independent AATs to the uptake of anti-[14C]FACBC in DU145 and PrECs were greater under acidic pH conditions than under neutral or alkaline pH conditions. Conclusions: Total uptake of anti-[14C]FACBC by PCa cells correlates with the expression level of system ASC in PCa cells. Furthermore, LAT1 is an

  16. Composition of quince (Cydonia oblonga Miller) seeds: phenolics, organic acids and free amino acids.

    Science.gov (United States)

    Silva, Branca M; Andrade, Paula B; Ferreres, Federico; Seabra, Rosa M; Oliveira, M Beatriz P P; Ferreira, Margarida A

    2005-04-01

    Phenolic compounds, organic acids and free amino acids of quince seeds were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. Quince seeds presented a phenolic profile composed of 3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and 3,5-dicaffeoylquinic acids, lucenin-2, vicenin-2, stellarin-2, isoschaftoside, schaftoside, 6-C-pentosyl-8-C-glucosyl chrysoeriol and 6-C-glucosyl-8-C-pentosyl chrysoeriol. Six identified organic acids constituted the organic acid profile of quince seeds: citric, ascorbic, malic, quinic, shikimic and fumaric acids. The free amino acid profile was composed of 21 identified free amino acids and the three most abundant were glutamic and aspartic acids and asparagine. PMID:15702641

  17. Separation and identification of amino acids from lignite humic acids by thin layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Damian, L.; Marutoiu, C.; Niac, G.

    1985-07-01

    Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine. 8 references.

  18. Renal cortex taurine content regulates renal adaptive response to altered dietary intake of sulfur amino acids.

    OpenAIRE

    Chesney, R W; Gusowski, N; Dabbagh, S

    1985-01-01

    Rats fed a reduced sulfur amino acid diet (LTD) or a high-taurine diet (HTD) demonstrate a renal adaptive response. The LTD results in hypotaurinuria and enhanced brush border membrane vesicle (BBMV) accumulation of taurine. The HTD causes hypertaurinuria and reduced BBMV uptake. This adaptation may relate to changes in plasma or renal cortex taurine concentration. Rats were fed a normal-taurine diet (NTD), LTD, or HTD for 14 d or they underwent: (a) 3% beta-alanine for the last 8 d of each d...

  19. Amino Acid Prodrugs: An Approach to Improve the Absorption of HIV-1 Protease Inhibitor, Lopinavir

    Directory of Open Access Journals (Sweden)

    Mitesh Patel

    2014-04-01

    Full Text Available Poor systemic concentrations of lopinavir (LPV following oral administration occur due to high cellular efflux by P-glycoprotein (P-gp and multidrug resistance-associated proteins (MRPs and extensive metabolism by CYP3A4 enzymes. In this study, amino acid prodrugs of LPV were designed and investigated for their potential to circumvent efflux processes and first pass effects. Three amino acid prodrugs were synthesized by conjugating isoleucine, tryptophan and methionine to LPV. Prodrug formation was confirmed by the LCMS/MS and NMR technique. Interaction of LPV prodrugs with efflux proteins were carried out in P-gp (MDCK-MDR1 and MRP2 (MDCK-MRP2 transfected cells. Aqueous solubility studies demonstrated that prodrugs generate higher solubility relative to LPV. Prodrugs displayed higher stability under acidic conditions and degraded significantly with rise in pH. Uptake and transport data suggested that prodrugs carry significantly lower affinity towards P-gp and MRP2 relative to LPV. Moreover, prodrugs exhibited higher liver microsomal stability relative to LPV. Hence, amino acid prodrug modification might be a viable approach for enhancing LPV absorption across intestinal epithelial and brain endothelial cells which expresses high levels of P-gp and MRP2.

  20. Amino acid catabolism and generation of volatiles by lactic acid bacteria

    OpenAIRE

    Tavaria, F. K.; Dahl, S.; Carballo, F. J.; Malcata, F. X.

    2002-01-01

    Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180- d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino acids, when incubated independently with each amino acid in free form or with a mixture thereof. Attempts...

  1. Proliferation-dependent changes in amino acid transport and glucose metabolism in glioma cell lines

    International Nuclear Information System (INIS)

    Amino acid imaging is increasingly being used for assessment of brain tumor malignancy, extent of disease, and prognosis. This study explores the relationship between proliferative activity, amino acid transport, and glucose metabolism in three glioma cell lines (U87, Hs683, C6) at different phases of growth in culture. Growth phase was characterized by direct cell counting, proliferation index determined by flow cytometry, and [3H]thymidine (TdR) accumulation, and was compared with the uptake of two non-metabolized amino acids ([14C]aminocyclopentane carboxylic acid (ACPC) and [14C]aminoisobutyric acid (AIB)), and [18F]fluorodeoxyglucose (FDG). Highly significant relationships between cell number (density), proliferation index, and TdR accumulation rate were observed in all cell lines (r>0.99). Influx (K1) of both ACPC and AIB was directly related to cell density, and inversely related to the proliferation index and TdR accumulation in all cell lines. The volume of distribution (Vd) for ACPC and AIB was lowest during rapid growth and highest during the near-plateau growth phase in all cell lines. FDG accumulation in Hs683 and C6 cells was unaffected by proliferation rate, growth phase, and cell density, whereas FDG accumulation was correlated with TdR accumulation, growth phase, and cell density in U87 cells. This study demonstrates that proliferation rate and glucose metabolism are not necessarily co-related in all glioma cell lines. The values of K1 and Vd for ACPC and AIB under different growth conditions suggest that these tumor cell lines can up-regulate amino acid transporters in their cell membranes when their growth conditions become adverse and less than optimal. (orig.)

  2. Tuning hardness in calcite by incorporation of amino acids

    Science.gov (United States)

    Kim, Yi-Yeoun; Carloni, Joseph D.; Demarchi, Beatrice; Sparks, David; Reid, David G.; Kunitake, Miki E.; Tang, Chiu C.; Duer, Melinda J.; Freeman, Colin L.; Pokroy, Boaz; Penkman, Kirsty; Harding, John H.; Estroff, Lara A.; Baker, Shefford P.; Meldrum, Fiona C.

    2016-08-01

    Structural biominerals are inorganic/organic composites that exhibit remarkable mechanical properties. However, the structure-property relationships of even the simplest building unit--mineral single crystals containing embedded macromolecules--remain poorly understood. Here, by means of a model biomineral made from calcite single crystals containing glycine (0-7 mol%) or aspartic acid (0-4 mol%), we elucidate the origin of the superior hardness of biogenic calcite. We analysed lattice distortions in these model crystals by using X-ray diffraction and molecular dynamics simulations, and by means of solid-state nuclear magnetic resonance show that the amino acids are incorporated as individual molecules. We also demonstrate that nanoindentation hardness increased with amino acid content, reaching values equivalent to their biogenic counterparts. A dislocation pinning model reveals that the enhanced hardness is determined by the force required to cut covalent bonds in the molecules.

  3. Amino-containing magnetic nanoemulsions: elaboration and nucleic acid extraction

    International Nuclear Information System (INIS)

    Amino-containing magnetic colloids were prepared from highly magnetic oil-in-water (O/W) emulsions. The functionalization was performed by controlling the adsorption of polyethyleneimine onto negatively charged magnetic emulsions. The cationic magnetic nanodroplets were characterized in terms of chemical composition, particle size, size distribution, zeta potential and colloidal stability as a function of storage time. These amino-containing magnetic emulsions were assessed as a new tool for nucleic acid extraction and amplification. The adsorption of nucleic acids was mostly controlled by attractive electrostatic interactions. The adsorption efficiency of a model RNA was found to be encouraging and the captured nucleic acid molecules were directly enzymatically amplified in the presence of the magnetic particles without any elution step

  4. Reactions of Hot Tritiúm Atoms with Amino Acids

    International Nuclear Information System (INIS)

    In the existing literature there is a lack of systematic data on the interaction of tritium recoil atoms with amino acids, yet such data, in conjunction with results already obtained for organic acids and amines, could help in determining the mechanism of hot reactions in relation to the structure of compounds (chain length, functional substitutes). A study was made of the yields from the reaction of hot tritium atoms: (1) with amino acids having lengthened chains, and (2) with amino acids having a carbon chain of constant length, but with various functional substitutes. For this purpose mixtures of lithium carbonate and the acids under study were irradiated for 15 min with a slow neutron flux of 0.87 x 1013 cm2/s. Analysis was carried out on a gas chromatography unit with interchangeable columns (molecular sieves, and liquid petrolatum on kieselguhr) and with paper chromatography. Although the data obtained for the radiation survival capacity of amino acids as a function of carbon chain length were at variance with a basic tenet of radiation chemistry according to which the conservation of molecules increases in proportion to the length of their chains, the data can be explained in terms of an intramolecular transfer of energy along the carbon chain from the collision site of the hot atom to the hydroxyl group, and subsequent ''de-excitation''; on the other hand, although the energy, of tritium recoil atoms is greater than that of the chemical bond, the latter nevertheless exerts an influence on the radiation conservation of molecules with a carbon chain of constant length but with various substitutes. (author)

  5. Studies of 3-amino-4-hydroxyl benzoic acid phosphate

    International Nuclear Information System (INIS)

    3-amino-4-hydroxyl benzoic acid phosphate was synthesized from 4-chloro benzoic acid through three steps, the whole process was cost-effective in which the materials in each step were reused. More importantly, phosphoric acid medium did no harm to Pd-C catalyst in the hydrogenation and the Pd-C catalyst could be recycled for ten times at least without decrease in catalytic activity. In addition, product could meet the requirement of polymerization reaction of producing poly(2,5-benzoxazole) without dehydrochlorogenation. In this process, good conversion, high overall yield (79.28%) and high purity (99.30% by HPLC) were achieved. (author)

  6. Protein and amino acid metabolism in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Guoyao.

    1989-01-01

    Isolated chick extensor digitorum communis (EDC) muscles and, in some experiments, rat skeletal muscles were used to study a number of aspects of protein and amino acid metabolism. (1) Chick EDC muscles synthesize and release large amounts of alanine and glutamine, which indirectly obtain their amino groups from branched-chain amino acids (BCAA). (2) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) decrease (P < 0.01) alanine synthesis and BCAA transamination in EDC muscles from 24-h fasted chicks by decreasing (P < 0.01) intracellular concentrations of pyruvate due to inhibition of glycolysis. (3) Glutamine is extensively degraded in skeletal muscles from both chicks and rats, thus challenging the traditional view that glutamine oxidation is negligible in skeletal muscle. The cytosolic glutamine aminotransferases L and K in the rat and the mitochondrial phosphate-activated glutaminase in the chick play important roles in the conversion of glutamine to {alpha}-ketoglutarate for further oxidation. (4) Although methionine has been reported to be extensively transaminated in rat skeletal muscle preparations in the absence of other amino acids, transamination of methionine is absent or negligible in chick and rat skeletal muscles in the presence of physiological concentrations of amino acids. (5) Glutamine at 1.0-15 mM increases (P < 0.01) protein synthesis ({sup 3}H-phenylalanine incorporation), and at 10.0-15.0 mM decreases (P < 0.05) protein degradation ({sup 3}H-phenylalanine release from prelabelled protein in vivo) in EDC muscles from fed chicks as compared to muscles incubated in the absence of glutamine. (6) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) has a small but significant inhibitory effect (P < 0.05) on the rate of protein synthesis, but has no effect (P > 0.05) on the rate of protein degradation in EDC muscles from fed chicks.

  7. Probing the Specificity Determinants of Amino Acid Recognition by Arginase

    Energy Technology Data Exchange (ETDEWEB)

    Shishova, E.; Di Costanzo, L; Emig, F; Ash, D; Christianson, D

    2009-01-01

    Arginase is a binuclear manganese metalloenzyme that serves as a therapeutic target for the treatment of asthma, erectile dysfunction, and atherosclerosis. In order to better understand the molecular basis of inhibitor affinity, we have employed site-directed mutagenesis, enzyme kinetics, and X-ray crystallography to probe the molecular recognition of the amino acid moiety (i.e., the ?-amino and ?-carboxylate groups) of substrate l-arginine and inhibitors in the active site of arginase I. Specifically, we focus on (1) a water-mediated hydrogen bond between the substrate ?-carboxylate and T135, (2) a direct hydrogen bond between the substrate ?-carboxylate and N130, and (3) a direct charged hydrogen bond between the substrate ?-amino group and D183. Amino acid substitutions for T135, N130, and D183 generally compromise substrate affinity as reflected by increased KM values but have less pronounced effects on catalytic function as reflected by minimal variations of kcat. As with substrate KM values, inhibitor Kd values increase for binding to enzyme mutants and suggest that the relative contribution of intermolecular interactions to amino acid affinity in the arginase active site is water-mediated hydrogen bond < direct hydrogen bond < direct charged hydrogen bond. Structural comparisons of arginase with the related binuclear manganese metalloenzymes agmatinase and proclavaminic acid amidinohydrolase suggest that the evolution of substrate recognition in the arginase fold occurs by mutation of residues contained in specificity loops flanking the mouth of the active site (especially loops 4 and 5), thereby allowing diverse guanidinium substrates to be accommodated for catalysis.

  8. Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability

    DEFF Research Database (Denmark)

    Johannsen, Marie Willaing; Wengel, Jesper; Wamberg, Michael Chr.;

    2010-01-01

    The synthesis of 2'-amino-LNA (locked nucleic acid) opens up exciting possibilities for modification of nucleic acids by conjugation to the 2'-nitrogen. Incorporation of unmodified and N-functionalized 2'-amino-LNA nucleotides improve duplex stability compared to unmodified DNA. 2'-Amino......-LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability....

  9. The cysteine, total sulfur amino acid, tyrosine, phenylalanine + tyrosine, and non-essential amino acid maintenance requirements of broiler breeders.

    Science.gov (United States)

    Ekmay, R D; Mei, S J; Sakomura, N K; Coon, C N

    2016-06-01

    Two hundred and fifty Cobb-Vantress broiler breeders were used to determine the maintenance requirement and efficiency of utilization of dietary Cys, Tyr, and non-essential amino acids (AA) in a 21-day experiment. The breeders were fed crystalline amino acid diets containing graded levels of Cys or Tyr representing 0, 10, 20, 30, and 40% of their suggested requirement level with all other amino acids maintained at 40% of their suggested requirement level. To determine the non-essential AA maintenance requirement, graded levels of non-essential AA were provided by glutamic acid to represent 12, 19, 26, 33, and 40% of the ideal level of glutamic acid with all other amino acids maintained at their maintenance requirement level. The total sulfur amino acid (TSAA) and Phe + Tyr requirements were calculated by combining Cys and Tyr results, respectively, with previously determined Met and Phe, respectively. The slope of Cys, Tyr, and non-essential AA accretion regression line indicated that 29% Cys, 24% TSAA, 21% Tyr, 20% Phe + Tyr, and 9% non-essential AA of crystalline amino acids were retained. The Cys requirement for zero protein accretion was calculated to be 30.48 mg/d or 17.006 mg/ kgBW(0.75)/d or 75.426 mg/kgCP/d. The TSAA requirement for zero accretion was calculated to be 132.25 mg/b/d, 71.48 mg/kgBW(0.75)/d, and 307.55 mg/kgCP/d. The Tyr requirement for zero protein accretion was calculated to be 65.907 mg/d or 37.233 mg/ kgBW(0.75)/d or 175.566 mg/kgCP/d. The Phe + Tyr requirement for zero protein accretion was calculated to be 352.18 mg/b/d, 190.37 mg/kgBW(0.75)/d, and 749.33 mg/kgCP/d. The non-essential AA requirement for zero protein accretion was calculated to be 3715.194 mg/d or 2003.155 mg/kgBW(0.75)/d or 9452.954 mg/kgCP/d. PMID:26994191

  10. LC/ESI-MS analysis of underivatized amino acids and mass spectrum

    CERN Document Server

    Takano, Yoshinori; Ohkouchi, Naohiko

    2016-01-01

    We report the method of LC/ESI-MS analysis of underivatized amino acids with corresponding mass spectrum and fragmentation patterns. Diagnostic product ions determined by mass spectrometry can support the qualitative identification and quantitative estimation of individual amino acids. Therefore, the optimization of chromatographic separation using the ion-pairing reagent (i.e., Nonafluoropentanoic acid, NFPA) is useful for the evaluation of target amino acid and for further compound-specific nitrogen isotope studies of amino acids.

  11. Targeting Amino Acid Metabolism for Molecular Imaging of Inflammation Early After Myocardial Infarction.

    Science.gov (United States)

    Thackeray, James T; Bankstahl, Jens P; Wang, Yong; Wollert, Kai C; Bengel, Frank M

    2016-01-01

    Acute tissue inflammation after myocardial infarction influences healing and remodeling and has been identified as a target for novel therapies. Molecular imaging holds promise for guidance of such therapies. The amino acid (11)C-methionine is a clinically approved agent which is thought to accumulate in macrophages, but not in healthy myocytes. We assessed the suitability of positron emission tomography (PET) with (11)C-methionine for imaging post-MI inflammation, from cell to mouse to man. Uptake assays demonstrated 7-fold higher (11)C-methionine uptake by polarized pro-inflammatory M1 macrophages over anti-inflammatory M2 subtypes (ptranslation of novel image-guided, inflammation-targeted regenerative therapies. PMID:27570549

  12. Photo-CIDNP studies of amino acids and proteins

    International Nuclear Information System (INIS)

    The ultimate aim of the research described in this thesis is the development of methods with which ope may study the structure and function of proteins on a molecular level. This is done with the help of a combination of NMR (Nuclear Magnetic Resonance) and flash photolysis, in which light initiated reactions between a chromophore and an amino acid induce abnormal NMR intensities. Chapters 1, 2 and 3: In the first chapter, a brief introduction of CIDNP and its application to proteins is given, followed by a short description of each chapter. The second chapter is an introductory review, covering the basics of the NMR experiment in the first part, and the theory behind the CIDNP phenomenon in the second. Chapter three describes the experimental apparatus and methods. Chapter 4: Photosensitization The light initiated chemical reaction between photosensitizer and amino acid residue is studied in detail for the case of FMN (flavinmononucleotide) and the amino acids tyrosine, tryptophan and histidine. An introduction is given of further sensitizers which have been found to generate CIDNP on amino acids, and which are used in later chapters. Chapter 5: CIDNP of Amino Acids and Proteins The typical CIDNP spectra of the amino acids tyrosine, tryptophan and histidine are introduced and elucidated in the first half of this chapter. Photo-CIDNP on the proteins ribonuclease A and Hen Egg White Lysozyme with the photosensitizers FMN, thionin and eosin Y are described in the second half. Chapter 6: CIDNP in Micellar Solutions The presence of detergent, below and above the critical micelle concentration, is shown to affect CIDNP intensities, due to electrostatic interactions between charged dye and detergent molecules. In the last part of this chapter, photo-CIDNP experiments with the membrane protein gramicidin A, incorporated in detergent and lipid micelles, are described. Chapter 7: CIDNP Study of the Tryptophan Radical CIDNP spectra are characteristic of the transient radical

  13. Photo-CIDNP studies of amino acids and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.J

    2001-07-01

    The ultimate aim of the research described in this thesis is the development of methods with which ope may study the structure and function of proteins on a molecular level. This is done with the help of a combination of NMR (Nuclear Magnetic Resonance) and flash photolysis, in which light initiated reactions between a chromophore and an amino acid induce abnormal NMR intensities. Chapters 1, 2 and 3: In the first chapter, a brief introduction of CIDNP and its application to proteins is given, followed by a short description of each chapter. The second chapter is an introductory review, covering the basics of the NMR experiment in the first part, and the theory behind the CIDNP phenomenon in the second. Chapter three describes the experimental apparatus and methods. Chapter 4: Photosensitization The light initiated chemical reaction between photosensitizer and amino acid residue is studied in detail for the case of FMN (flavinmononucleotide) and the amino acids tyrosine, tryptophan and histidine. An introduction is given of further sensitizers which have been found to generate CIDNP on amino acids, and which are used in later chapters. Chapter 5: CIDNP of Amino Acids and Proteins The typical CIDNP spectra of the amino acids tyrosine, tryptophan and histidine are introduced and elucidated in the first half of this chapter. Photo-CIDNP on the proteins ribonuclease A and Hen Egg White Lysozyme with the photosensitizers FMN, thionin and eosin Y are described in the second half. Chapter 6: CIDNP in Micellar Solutions The presence of detergent, below and above the critical micelle concentration, is shown to affect CIDNP intensities, due to electrostatic interactions between charged dye and detergent molecules. In the last part of this chapter, photo-CIDNP experiments with the membrane protein gramicidin A, incorporated in detergent and lipid micelles, are described. Chapter 7: CIDNP Study of the Tryptophan Radical CIDNP spectra are characteristic of the transient radical

  14. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of...

  15. Comparative functional genomics of amino acid metabolism of lactic acid bacteria

    OpenAIRE

    Pastink, M.I.

    2009-01-01

    The amino acid metabolism of lactic acid bacteria used as starters in industrial fermentations has profound effects on the quality of the fermented foods. The work described in this PhD thesis was initiated to use genomics technologies and a comparative approach to link the gene content of some well-known lactic acid bacteria to flavor formation and to increase our general knowledge in the area of amino acid metabolism. The three well-known lactic acid bacteria that were used in these studies...

  16. /sup 13/N-labeled L-amino acids for in vivo assessment of local myocardial metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, F.J.; Barrio, J.R.; Henze, E.; Schelbert, H.R.; MacDonald, N.S.; Phelps, M.E.; Kuhl, D.E.

    1981-06-01

    The hot cell synthesis of sterile, pyrogen-free /sup 13/N-labeled L-amino acids was accomplished by employing the appropriate immobilized enzymes on a CNBr-activated Sepharose support and using remote, semiautomated systems. The syntheses were completed 6-12 min after cyclotron production of (/sup 13/N)ammonia. Myocardial time-activity curves after intracoronary injection of /sup 13/N-labeled L-amino acids in dogs were triexponential in both normal and ischemic myocardium. Higher retention of /sup 13/N activity was observed in ischemic segments. Positron computed tomography imaging also showed increased uptake of /sup 13/N-labeled L-glutamate and L-alanine in ischemic segments compared with normal myocardium when blood flow corrections were made. Myocardial transaminases are primarily responsible for the observed retention fractions. It suggests the participation of the carbon skeletons of these amino acids in the Krebs cycle.

  17. INTERACTION OF AMINO ACID WITH ION EXCHANGE RESIN Ⅲ.FURTHER INVESTIGA TION OF SUPEREQUIVALENT ADSORPTION MECHANISM OF AMINO ACID ON ION EXCHANGE RESIN

    Institute of Scientific and Technical Information of China (English)

    ZHANGHui; SHAOTong; 等

    1994-01-01

    The adsorption isotherms of glycine,alanine and oxidized glutathion on strong acid cation and strong base anion exchange resins from aqueous solutions were measured and the superequivalent adsorptions of glycine and alanine observed.The infrared spectra of glycine adsorbed on the cation and the anion exchange resins,001×7 and 201×7,were measured.From these results,it is concluded that the amino acid adsorption on the ion exchange resin proceeds not only through ion exchange and proton transfer mechanisms,but also through aminecarboxylate interaction between the adsorbed amino acid molecules,and the formation of second layer of amino acid molecules is the mechanism of superequivalent adsorption of amino acid,the carboxylate or amine groups of the first layer of amino acid molecules on the ion exchange resin act as the exchange sites for the second layer of amino acid molecules.

  18. Sensitive determination of D-amino acids in mammals and the effect of D-amino-acid oxidase activity on their amounts.

    Science.gov (United States)

    Hamase, Kenji; Konno, Ryuichi; Morikawa, Akiko; Zaitsu, Kiyoshi

    2005-09-01

    The determination of small amounts of D-amino acids in mammalian tissues is still a challenging theme in the separation sciences. In this review, various gas-chromatographic and high-performance liquid chromatographic methods are discussed including highly selective and sensitive column-switching procedures. Based on these methods, the distributions of D-aspartic acid, D-serine, D-alanine, D-leucine and D-proline have been clarified in the mouse brain. As the regulation mechanisms of D-amino acid amounts in mammals, we focused on the D-amino-acid oxidase, which catalyzes the degradation of D-amino acids. Using the mutant mouse strain lacking D-amino-acid oxidase activity, the effects of the enzymatic activity on the amounts and distributions of various D-amino acids have been investigated. PMID:16141519

  19. (Amino acid + silica) adsorption thermodynamics: Effects of temperature

    International Nuclear Information System (INIS)

    Highlights: • High resolution, low concentration Gly, Lys and Glu solution adsorption isotherms. • All isotherms fitted with Langmuir–Freundlich isotherm model. • Gly, Lys and Glu show exothermic adsorption processes. • Isosteric heat analyses reveal changes in interaction strength with surface coverage. - Abstract: A thorough understanding of amino acid adsorption by mineral and oxide surfaces has a major impact on a variety of industrial and biomedical applications. Little information currently exists regarding temperature effects on most of these adsorption processes. Deeper thermodynamic analyses of their multiple temperature adsorption isotherms would aid the interpretation of the interfacial interactions. Low solution concentration adsorption isotherms for glycine, lysine and glutamic acid on a silica adsorbent were generated for T = (291, 298 and 310) K. Data analysis via the Clausius–Clapeyron method yielded the isosteric heat of adsorption as a function of fractional monolayer coverage for each adsorptive. Each amino acid showed an exothermic adsorption response. Glycine and lysine experienced a greater negative effect of increased temperature compared with glutamic acid, indicating a greater number of adsorbed molecules than glutamic acid, with the former undergoing intermolecular clustering within the adsorbed phase. Isosteric heat analyses suggest ionic interactions for lysine and hydrogen bonding for glutamic acid, both weakening with increased coverage. In contrast, initial hydrogen bonding led to ionic bonding for glycine with increasing coverage

  20. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

    OpenAIRE

    Tareq Irshaidat

    2014-01-01

    On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293) illustrated that beryllium ions are capable of significantly modulating (changing) the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF2(1+), AlF2+, and Al3+) were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation ana...

  1. Informational Way to Protein Alphabet: Entropic Classification of Amino Acids

    CERN Document Server

    Gorban, A N; Popova, T

    2007-01-01

    What are proteins made from, as the working parts of the living cells protein machines? To answer this question, we need a technology to disassemble proteins onto elementary func-tional details and to prepare lumped description of such details. This lumped description might have a multiple material realization (in amino acids). Our hypothesis is that informational approach to this problem is possible. We propose a way of hierarchical classification that makes the primary structure of protein maximally non-random. The first steps of the suggested research program are realized: the method and the analysis of optimal informational protein binary alphabet. The general method is used to answer several specific questions, for example: (i) Is there a syntactic difference between Globular and Membrane proteins? (ii) Are proteins random sequences of amino acids (a long discussion)? For these questions, the answers are as follows: (i) There exists significant syntactic difference between Globular and Membrane proteins,...

  2. Topological features of proteins from amino acid residue networks

    CERN Document Server

    Alves, N A; Alves, Nelson Augusto; Martinez, Alexandre Souto

    2006-01-01

    Topological properties of native folds are obtained from statistical analysis of 160 low homology proteins covering the four structural classes. This is done analysing one, two and three-vertex joint distribution of quantities related to the corresponding network of amino acid residues. Emphasis on the amino acid residue hydrophobicity leads to the definition of their center of mass as vertices in this contact network model with interactions represented by edges. The network analysis helps us to interpret experimental results such as hydrophobic scales and fraction of buried accessible surface area in terms of the network connectivity. To explore the vertex type dependent correlations, we build a network of hydrophobic and polar vertices. This procedure presents the wiring diagram of the topological structure of globular proteins leading to the following attachment probabilities between hydrophobic-hydrophobic 0.424(5), hydrophobic-polar 0.419(2) and polar-polar 0.157(3) residues.

  3. Amino Acids Catalyzed Direct Aldol Reactions in Aqueous Micelles

    Institute of Scientific and Technical Information of China (English)

    PENG Yi-Yuan; WANG Qi; DING Qiu-Ping; HE Jia-Qi; CHENG Jin-Pei

    2003-01-01

    @@ Since the discovery of its roles as a good small-organic-molecule catalyst in intramolecular aldol reactions, pro line has drawn considerable attention in synthetic chemistry due to its similarity to the type-Ⅰ aldolases. Recently,List and others have reported some new direct asymmetric intermolecular reactions catalyzed by proline, including aldol, Mannich, Michael, and other analogous reactions. Except for two recent examples, [1,2] proline catalyzed aldol reactions in aqueous micelles have not been reported, nor have other amino acids as organocatalysts in directly catalyzing aldol reaction been reported. Herein we wish to present our recent results regarding environmentally be nign direct aldol reactions catalyzed by amino acids including proline, histidine and arginine in aqueous media.

  4. Direct amidation of amino acid derivatives catalyzed by arylboronic acids : applications in dipeptide synthesis.

    OpenAIRE

    Liu, S.; Yang, Y.; Liu, X.; Ferdousi, F. K.; Batsanov, A.S.; Whiting, A

    2013-01-01

    The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65–68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids ...

  5. Correlation between fibroin amino acid sequence and physical silk properties.

    Science.gov (United States)

    Fedic, Robert; Zurovec, Michal; Sehnal, Frantisek

    2003-09-12

    The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet. PMID:12816957

  6. Addicting diverse bacteria to a noncanonical amino acid.

    Science.gov (United States)

    Tack, Drew S; Ellefson, Jared W; Thyer, Ross; Wang, Bo; Gollihar, Jimmy; Forster, Matthew T; Ellington, Andrew D

    2016-03-01

    Engineered orthogonal translation systems have greatly enabled the expansion of the genetic code using noncanonical amino acids (NCAAs). However, the impact of NCAAs on organismal evolution remains unclear, in part because it is difficult to force the adoption of new genetic codes in organisms. By reengineering TEM-1 β-lactamase to be dependent on a NCAA, we maintained bacterial NCAA dependence for hundreds of generations without escape. PMID:26780407

  7. Quantitative detection of single amino acid polyrnorphisms by targeted proteornics

    Institute of Scientific and Technical Information of China (English)

    Zhi-Duan Su; Jia-Rui Wu; Liang Sun; Dan-Xia Yu; Rong-Xia Li; Huai-Xing Li; Zhi-Jie Yu; Quan-Hu Sheng; Xu Lin; RongZeng

    2011-01-01

    Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale. However, polymorphisms at the proteome level in population scale remain elusive. In the present study, we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level, and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma. The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach, and their associations with both obesity and diabetes were further analyzed. This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits. In addition, the SRM approach allows us for the first time to separately measure the absolute concentration of each SAP peptide in the heterozygotes, which also shows different associations with particular traits.%Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale.However,polymorphisms at the proteome level in population scale remain elusive.In the present study,we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level,and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma.The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach,and their associations with both obesity and diabetes were further analyzed.This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits.In addition,the SRM approach allows us for the first time to separately measure the absolute

  8. Hypothalamic signaling in anorexia induced by indispensable amino acid deficiency

    OpenAIRE

    Zhu, Xinxia; Krasnow, Stephanie M.; Roth-Carter, Quinn R.; Levasseur, Peter R.; Braun, Theodore P.; Grossberg, Aaron J.; Marks, Daniel L.

    2012-01-01

    Animals exhibit a rapid and sustained anorexia when fed a diet that is deficient in a single indispensable amino acid (IAA). The chemosensor for IAA deficiency resides within the anterior piriform cortex (APC). Although the cellular and molecular mechanisms by which the APC detects IAA deficiency are well established, the efferent neural pathways that reduce feeding in response to an IAA-deficient diet remain to be fully characterized. In the present work, we investigated whether 1) central m...

  9. Chiroptical Properties of Amino Acids: A Density Functional Theory Study

    OpenAIRE

    Martine Adrian-Scotto; Serge Antonczak; Jan Hendrik Bredehöft; Hoffmann, Søren V.; Meierhenrich, Uwe J.

    2010-01-01

    Amino acids are involved in many scientific theories elucidating possible origins of life on Earth. One of the challenges when discussing the evolutionary origin of biopolymers such as proteins and oligonucleotides in living organisms is the phenomenon that these polymers implement monomers of exclusively one handedness, a feature called biomolecular homochirality. Many attempts have been made to understand this process of racemic symmetry breaking. Assuming an extraterrestrial origin of the ...

  10. Evaluation of Physiological Amino Acids Profiling by Tandem Mass Spectrometry

    OpenAIRE

    Filee, Romain; Schoos, Roland; Boemer, François

    2013-01-01

    Background: Nowadays, the most conventional method to quantify physiological amino acids consists in ion exchange chromatography (IEC) followed by post-column ninhydrin derivatization and UV detection at two wavelengths. Unfortunately, the technique presents some drawbacks such as long run time, large sample volume, and specific costs associated to the maintenance of a dedicated instrument. Therefore, we aimed to switch towards a mass spectrometry approach.

  11. Dynamics of human whole body amino acid metabolism

    International Nuclear Information System (INIS)

    The mechanism of regulation of the nitrogen metabolism in humans under various nutritional and physiological states was examined using stable isotopes. In the simultaneous continuous infusion of 1- [13] - leucine and α- [15N]- lysine, their fluxed decreased when individuals received lower protein intake. The rates of oxidation and incorporation into body proteins of leucine changed in parallel with the protein intake. Such effects of diet on whole body leucine kinetics were modified by the energy state and dietary energy level. The nitrogen balance was also improved by an excess level of dietary energy. When the intake of dietary protein was lowered below the maintenance level, the whole body flux and de novo synthesis of glycine were lowered, but alanine synthesis was clearly increased. The intravenous infusion of glucose at 4 mg/kg.min, which causes increase in excess blood sugar and plasma insulin, increased the alanine flux, but had no effect on the glycine flux. The rate of albumin synthesis, determined by giving 15N-glycine orally every 3 hr, decreased with the lowered intake of dietary protein in young men, but not in elderly men. This explains why the serum albumin synthesis increases with the increase in the intake of dietary protein in young men, but not in elderly men. The rate of whole body protein synthesis in young men receiving the L-amino acid diets providing with the required intake of specific amino acid was much lower than that in the men receiving the diets providing with generous intake of specific amino acid. Thus the control mechanism to maintain the homeostasis of body nitrogen and amino acids is related in some unknown way to the nutritional requirement of the hosts. (Kaihara, S.)

  12. SSE: a nucleotide and amino acid sequence analysis platform

    OpenAIRE

    Simmonds Peter

    2012-01-01

    Abstract Background There is an increasing need to develop bioinformatic tools to organise and analyse the rapidly growing amount of nucleotide and amino acid sequence data in organisms ranging from viruses to eukaryotes. Finding A simple sequence editor (SSE) was developed to create an integrated environment where sequences can be aligned, annotated, classified and directly analysed by a number of built-in bioinformatic programs. SSE incorporates a sequence editor for the creation of sequenc...

  13. Amino acid-sensing ion channels in plants

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, Edgar P.

    2014-08-12

    The title of our project is “Amino acid-sensing ion channels in plants”. Its goals are two-fold: to determine the molecular functions of glutamate receptor-like (GLR) proteins, and to elucidate their biological roles (physiological or developmental) in plants. Here is our final technical report. We were highly successful in two of the three aims, modestly successful in the third.

  14. Correlated Mutations: A Hallmark of Phenotypic Amino Acid Substitutions

    OpenAIRE

    Kowarsch, Andreas; Fuchs, Angelika; Frishman, Dmitrij; Pagel, Philipp

    2010-01-01

    Point mutations resulting in the substitution of a single amino acid can cause severe functional consequences, but can also be completely harmless. Understanding what determines the phenotypical impact is important both for planning targeted mutation experiments in the laboratory and for analyzing naturally occurring mutations found in patients. Common wisdom suggests using the extent of evolutionary conservation of a residue or a sequence motif as an indicator of its functional importance an...

  15. Fluoroalkyl chloroformates in treating amino acids for gas chromatographic analysis

    Czech Academy of Sciences Publication Activity Database

    Hušek, Petr; Šimek, Petr; Hartvich, Petr; Zahradníčková, Helena

    2008-01-01

    Roč. 1186, 1/2 (2008), s. 391-400. ISSN 0021-9673 R&D Projects: GA ČR GA203/04/0192; GA ČR GA303/06/1674 Institutional research plan: CEZ:AV0Z50070508 Keywords : amino acids * derivatization * pentafluoropropyl- and heptafluorobutyl chloroformates Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.756, year: 2008

  16. Computational Design of Multinuclear Metalloproteins Using Unnatural Amino Acids.

    Science.gov (United States)

    Hansen, William A; Mills, Jeremy H; Khare, Sagar D

    2016-01-01

    Multinuclear metal ion clusters, coordinated by proteins, catalyze various critical biological redox reactions, including water oxidation in photosynthesis, and nitrogen fixation. Designed metalloproteins featuring synthetic metal clusters would aid in the design of bio-inspired catalysts for various applications in synthetic biology. The design of metal ion-binding sites in a protein chain requires geometrically constrained and accurate placement of several (between three and six) polar and/or charged amino acid side chains for every metal ion, making the design problem very challenging to address. Here, we describe a general computational method to redesign oligomeric interfaces of symmetric proteins for the purpose of creating novel multinuclear metalloproteins with tunable geometries, electrochemical environments, and metal cofactor stability via first and second-shell interactions.The method requires a target symmetric organometallic cofactor whose coordinating ligands resemble the side chains of a natural or unnatural amino acid and a library of oligomeric protein structures featuring the same symmetry as the target cofactor. Geometric interface matches between target cofactor and scaffold are determined using a program that we call symmetric protein recursive ion-cofactor sampler (SyPRIS). First, the amino acid-bound organometallic cofactor model is built and symmetrically aligned to the axes of symmetry of each scaffold. Depending on the symmetry, rigid body and inverse rotameric degrees of freedom of the cofactor model are then simultaneously sampled to locate scaffold backbone constellations that are geometrically poised to incorporate the cofactor. Optionally, backbone remodeling of loops can be performed if no perfect matches are identified. Finally, the identities of spatially proximal neighbor residues of the cofactor are optimized using Rosetta Design. Selected designs can then be produced in the laboratory using genetically incorporated unnatural

  17. Effect of Carbon and Nitrogen Availability on Metabolism of Amino Acids in Germinating Spores of Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    JIN Hai-Ru; JIANG Dong-Hua; ZHANG Ping-Hua

    2011-01-01

    The effects of carbon (C) and nitrogen (N) sources on N utilization and biosynthesis of amino acids were examined in the germinating spores of the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith after exposure to various N substrates,CO2,glucose,and/or root exudates.The N uptake and de novo biosynthesis of amino acids were analyzed using stable isotopic labeling with mass spectrometric detection.High-performance liquid chromatography-based analysis was used to measure amino acid levels.In the absence of exogenous N sources and in the presence of 25 mL L-1 CO2,the germinating AM fungal spores utilized internal N storage as well as C skeletons derived from the degradation of storage lipids to biosynthesize the free amino acids,in which serine and glycine were produced predominantly.The concentrations of internal amino acids increased gradually as the germination time increased from 0 to 1 or 2 weeks.However,asparagine and glutamine declined to the low levels; both degraded to provide the biosynthesis of other amino acids with C and N donors.The availability of exogenous inorganic N (ammonium and nitrate) and organic N (urea,arginine,and glutamine) to the AM fungal spores using only CO2 for germination generated more than 5 times more internal free amino acids than those in the absence of exogenous N.A supply of exogenous nitrate to the AM fungal spores with only CO2 gave rise to more than 10 times more asparagine than that without exogenous N.In contrast,the extra supply of exogenous glucose to the AM fungal spores generated a significant enhancement in the uptake of exogenous N sources,with more than 3 times more free amino acids being produced than those supplied with only exogenous CO2.Meanwhile,arginine was the most abundant free amino acid produced and it was incorporated into the proteins of AM fungal spores to serve as an N storage compound.

  18. The Synthesis of Some Novel N-[a-(Isoflavone-7-O-)Acetyl ] Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of novel N-[(α)-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.

  19. In vivo unnatural amino acid expression in the methylotrophic yeast Pichia pastoris

    Science.gov (United States)

    Young, Travis [San Diego, CA; Schultz, Peter G [La Jolla, CA

    2014-02-11

    The invention provides orthogonal translation systems for the production of polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris. Methods for producing polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris are also provided.

  20. Amino acid distance matrices and classifications for different protein secondary structure

    CERN Document Server

    Zhang, L; Guan, S; Zheng, W M; Zhang, Li-mei; Liu, Xin; Guan, Shan; Zheng, Wei-Mou

    2003-01-01

    The property of an amino acid is different according to the variation of protein secondary structure. Each central amino acid corresponds to a position specific amino acid distribution around it. Based on the probability distribution for the central amino acid, we get amino acid distance matrices and classifications for helix, sheet, coil and turn. It is observed that evident discrepancy exists in amino acid distance for different protein secondary structure. Some obvious difference between the distance matrices and blocks substitution matrix(BLOSUM) is found which can tell the difference of amino acid property between in certain protein secondary structure and the whole protein database. The classification of amino acid alphabets for specific protein secondary structure provide a clue for observing these difference.

  1. Effect of gamma irradiation on the amino acid contents of seafood cooking drips

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju Woon; Kim, Yeon Joo; Choi, Jong Il; Kim, Yun Joo; Kim, Jae Hun; Kim, Jin Kyu; Byun, Myung Woo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kwon, Joong Ho [Dept. of Food Science and Technology, Kyungpook National University, Daegu (Korea, Republic of); Ahn, Dong Hyun; Chun, Byung Soo [Faculty of Food Science and Biotechnology, Pukyung Nationol University, Busan (Korea, Republic of)

    2008-11-15

    In this study, the effects of gamma irradiation on the change of structural and free amino acids contents of cooking drips from Hizikia fusiformis (HF) and Enteroctopus dofleini (ED) were investigated. The main structural amino acids were glutamic acid in HF cooking drip, and glutamic acid, glycine, arginine and aspartic acid in ED cooking drip, respectively. The concentrations of structural amino acids in both cooking drip extracts were decreased by the gamma irradiation at the dose of 10 kGy. Especially, the sulfur-containing amino acids were severely degraded by the irradiation. In free amino acid, ED cooking drip extract was contained the larger amount of free amino acid than that of HF cooking drip affecting its rich flavor. The free amino acid concentrations of cooking drips extracts from HF and ED were both increased by irradiation, and it explained the higher protein content by the irradiation.

  2. Synthesis of alkynes and alkynyl iodides bearing a protected amino alcohol moiety as functionalized amino acids precursors

    Institute of Scientific and Technical Information of China (English)

    AYED; Charfedinne; PICARD; Julien; LUBIN-GERMAIN; Nadège; UZIEL; Jacques; AUGE; Jacques

    2010-01-01

    Amino acid precursors in protected amino alcohol form are important synthons that can be used as building-blocks for the hemisynthesis of non-natural amino acids.Serine can be used as a common starting material for the synthesis of such compounds differently protected.Particularly,protected amino alcohols bearing an ethynyl and/or an iodoethynyl group can be used in cross-couplings,in 1,3-dipolar cycloadditions and/or in Nozaki-Hiyama-Kishi type reactions.We thus demonstrated that the efficiently protected amino alcohols derived from serine can be coupled to a sugar derivative by an indium mediated alkynylation reaction.The conditions of this coupling are compatible with such functionalized derivatives and allow envisaging an access to C-glycosylated amino acids.

  3. Effect of amino acids on the interaction between cobalamin(II) and dehydroascorbic acid

    Science.gov (United States)

    Dereven'kov, I. A.; Thi, Thu Thuy Bui; Salnikov, D. S.; Makarov, S. V.

    2016-03-01

    The kinetics of the reaction between one-electron-reduced cobalamin (cobalamin(II), Cb(II)) and the two-electron-oxidized form of vitamin C (dehydroascorbic acid, DHA) with amino acids in an acidic medium is studied by conventional UV-Vis spectroscopy. It is shown that the oxidation of Cbl(II) by dehydroascorbic acid proceeds only in the presence of sulfur-containing amino acids (cysteine, acetylcysteine). A proposed reaction mechanism includes the step of amino acid coordination on the Co(II)-center through the sulfur atom, along with that of the interaction between this complex and DHA molecules, which results in the formation of ascorbyl radical and the corresponding Co(III) thiolate complex.

  4. Phase Chemistry of the Complexes of RE Amino Acids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Forty-three phase diagrams of ternary system concerning rare earth salts, α-amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of “tripartite effect”, “tetrad effect”, “Nephelanxetic effect”, “Oddo-Harkins” was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth-amino acid-complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC-1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

  5. Branched chain amino acid profile in early chronic kidney disease

    Directory of Open Access Journals (Sweden)

    M Anil Kumar

    2012-01-01

    Full Text Available The nutritional status in chronic kidney disease (CKD patients is a predictor of prognosis during the first period of dialysis. Serum albumin is the most commonly used nutritional marker. Another index is plasma amino acid profile. Of these, the plasma levels of branched chain amino acids (BCAA, especially valine and leucine, correlate well with nutritional status. Plasma BCAAs were evaluated along with albumin and C-reactive protein in 15 patients of early stages of CKD and 15 age- and sex-matched healthy controls. A significant decrease in plasma valine, leucine and albumin levels was observed in CKD patients when compared with the controls (P <0.05. No significant difference in C-reactive protein (CRP levels was observed between the two groups. Malnutrition seen in our CKD patients in the form of hypoalbuminemia and decreased concentrations of BCAA points to the need to evaluate the nutritional status in the early stages itself. Simple measures in the form of amino acid supplementation should be instituted early to decrease the morbidity and mortality before start of dialysis in these patients.

  6. On the Maillard reaction of meteoritic amino acids

    Science.gov (United States)

    Kolb, Vera M.; Bajagic, Milica; Liesch, Patrick J.; Philip, Ajish; Cody, George D.

    2006-08-01

    We have performed the Maillard reaction of a series of meteoritic amino acids with sugar ribose under simulated prebiotic conditions, in the solid state at 65°C and at the room temperature. Many meteoritic amino acids are highly reactive with ribose, even at the room temperature. We have isolated high molecular weight products that are insoluble in water, and have studied their structure by the IR (infrared) and solid-state C-13 NMR (nuclear magnetic resonance) spectroscopic methods. The functional groups and their distribution were similar among these products, and were comparable to the previously isolated insoluble organic materials from the Maillard reaction of the common amino acids with ribose. In addition, there were some similarities with the insoluble organic material that is found on Murchison. Our results suggest that the Maillard products may contribute to the composition of the part of the insoluble organic material that is found on Murchison. We have also studied the reaction of sodium silicate solution with the Maillard mixtures, to elucidate the process by which the organic compounds are preserved under prebiotic conditions.

  7. Intravenous amino acids in third trimester isolated oligohydramnios

    International Nuclear Information System (INIS)

    To determine the efficacy of maternal administration of intravenous amino acid solution in improving amniotic fluid volume in cases of isolated oligohydramnios and to observe its impact on mode of delivery and neonatal outcome. Study Design: A prospective case series. Methodology: Forty two women with singleton pregnancy, well established gestational age and clinically and sonographically proven isolated oligohydramnios in the third trimester before 36 weeks were administered amino acid solution intravenously after excluding cases of premature rupture of membranes, congenital anomaly of fetus, maternal pulmonary, cardiovascular and hypertensive disorders, and severe placental insufficiency (raised S/D ratio). Pre-infusion and postinfusion Amniotic fluid Index (AFI) was measured and repeated weekly. Women were followed till delivery. Results: According to repeated measurement analysis of variance, mean pre-infusion AFI was 4.7 cm, mean one week postinfusion AFI was 5.8 cm, mean two week post-infusion AFI was 6.2 cm and mean three week AFI was 6.3 cm (p-value 0.029, significant). Cesarean section became a predominant mode of delivery in this group without a firm evidence of associated fetal compromise. Conclusion: Amino acid infusion is an effective therapy for raising AFI in isolated oligohydramnios in this case series. Liberal use of cesarean section in this selected group should be carefully re-evaluated. (author)

  8. Towards a Mathematical Foundation of Immunology and Amino Acid Chains

    CERN Document Server

    Shen, Wen-Jun; Xiao, Quan-Wu; Guo, Xin; Smale, Stephen

    2012-01-01

    We attempt to set a mathematical foundation of immunology and amino acid chains. To measure the similarities of these chains, a kernel on strings is defined using only the sequence of the chains and a good amino acid substitution matrix (e.g. BLOSUM62). The kernel is used in learning machines to predict binding affinities of peptides to human leukocyte antigens DR (HLA-DR) molecules. On both fixed allele (Nielsen and Lund 2009) and pan-allele (Nielsen et.al. 2010) benchmark databases, our algorithm achieves the state-of-the-art performance. The kernel is also used to define a distance on an HLA-DR allele set based on which a clustering analysis precisely recovers the serotype classifications assigned by WHO (Nielsen and Lund 2009, and Marsh et.al. 2010). These results suggest that our kernel relates well the chain structure of both peptides and HLA-DR molecules to their biological functions, and that it offers a simple, powerful and promising methodology to immunology and amino acid chain studies.

  9. Creatinyl amino acids: new hybrid compounds with neuroprotective activity.

    Science.gov (United States)

    Burov, Sergey; Leko, Maria; Dorosh, Marina; Dobrodumov, Anatoliy; Veselkina, Olga

    2011-09-01

    Prolonged oral creatine administration resulted in remarkable neuroprotection in experimental models of brain stroke. However, because of its polar nature creatine has poor ability to penetrate the blood-brain barrier (BBB) without specific creatine transporter (CRT). Thus, synthesis of hydrophobic derivatives capable of crossing the BBB by alternative pathway is of great importance for the treatment of acute and chronic neurological diseases including stroke, traumatic brain injury and hereditary CRT deficiency. Here we describe synthesis of new hybrid compounds-creatinyl amino acids, their neuroprotective activity in vivo and stability to degradation in different media. The title compounds were synthesized by guanidinylation of corresponding sarcosyl peptides or direct creatine attachment using isobutyl chloroformate method. Addition of lipophilic counterion (p-toluenesulfonate) ensures efficient creatine dissolution in DMF with simultaneous protection of guanidino group towards intramolecular cyclization. It excludes the application of expensive guanidinylating reagents, permits to simplify synthetic procedure and adapt it to large-scale production. The biological activity of creatinyl amino acids was tested in vivo on ischemic stroke and NaNO(2) -induced hypoxia models. One of the most effective compounds-creatinyl-glycine ethyl ester increases life span of experimental animals more than two times in hypoxia model and has neuroprotective action in brain stroke model when applied both before and after ischemia. These data evidenced that creatinyl amino acids can represent promising candidates for the development of new drugs useful in stroke treatment. PMID:21644247

  10. Microfabricated capillary electrophoresis amino acid chirality analyzer for extraterrestrial exploration

    Science.gov (United States)

    Hutt, L. D.; Glavin, D. P.; Bada, J. L.; Mathies, R. A.

    1999-01-01

    Chiral separations of fluorescein isothiocyanate-labeled amino acids have been performed on a microfabricated capillary electrophoresis chip to explore the feasibility of using such devices to analyze for extinct or extant life signs in extraterrestrial environments. The test system consists of a folded electrophoresis channel (19.0 cm long x 150 microns wide x 20 microns deep) that was photolithographically fabricated in a 10-cm-diameter glass wafer sandwich, coupled to a laser-excited confocal fluorescence detection apparatus providing subattomole sensitivity. Using a sodium dodecyl sulfate/gamma-cyclodextrin pH 10.0 carbonate electrophoresis buffer and a separation voltage of 550 V/cm at 10 degrees C, baseline resolution was observed for Val, Ala, Glu, and Asp enantiomers and Gly in only 4 min. Enantiomeric ratios were determined for amino acids extracted from the Murchison meteorite, and these values closely matched values determined by HPLC. These results demonstrate the feasibility of using microfabricated lab-on-a-chip systems to analyze extraterrestrial samples for amino acids.

  11. A single amino acid gates the KcsA channel

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Minako, E-mail: hirano37@gpi.ac.jp [Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku Hamamatsu, Shizuoka 431-1202 (Japan); Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Okuno, Daichi, E-mail: dokuno@riken.jp [Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Onishi, Yukiko, E-mail: yonishi@riken.jp [Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Ide, Toru, E-mail: ide@okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Kita-ku Okayama-shi, Okayama 700-8530 (Japan)

    2014-08-08

    Highlights: • pH-dependent gating of the KcsA channel is regulated by the CPD. • E146 is the most essential amino acid for pH sensing by the KcsA. • The protonated-mimicking mutant, E146Q, is constitutively open independent of pH. • Minimal rearrangement of the CPD is sufficient for opening of the KcsA. - Abstract: The KcsA channel is a proton-activated potassium channel. We have previously shown that the cytoplasmic domain (CPD) acts as a pH-sensor, and the charged states of certain negatively charged amino acids in the CPD play an important role in regulating the pH-dependent gating. Here, we demonstrate the KcsA channel is constitutively open independent of pH upon mutating E146 to a neutrally charged amino acid. In addition, we found that rearrangement of the CPD following this mutation was not large. Our results indicate that minimal rearrangement of the CPD, particularly around E146, is sufficient for opening of the KcsA channel.

  12. A Facile Method for Asymmetric Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    LI,Shuo; LI,Lei; ZHANG,Zhi-Hui; XU,Peng-Fei

    2004-01-01

    @@ β-Hydroxy-a-amino acids are an important class of amino acids due to their inherent biological investigations[1] and as structural components of more complex biomolecules.[2] β-Hydroxy-a-amino acids have been used as intermediates in the asymmetric synthesis of other compounds.[3] An efficient and convenient concise method for the preparation of optically pure enantiomers of β-hydroxy-α-amino acids would be of general interest.

  13. Content of amino acids and minerals in selected sorts of legumes

    OpenAIRE

    Stanislav Kráčmar; Pavel Švec; Petra Vojtíšková

    2013-01-01

    The aim of this study was to determine amino acid composition and mineral content in selected legume samples. All analyses were carried out at the laboratory temperature of 21±2 °C in triplicate. Amino acid composition was determined using the automatic amino acid analyzer AAA 400 with post-column derivatization. To assess the nutritional value of protein, index of essential amino acids (EAAI) was calculated. Minerals were determined using the atomic absorption spectrometer AA 30. All resu...

  14. Influence of irradiation on protein and amino acids in laboratory rodent diet

    International Nuclear Information System (INIS)

    The effect of irradiation treatment on the protein quality and constituent amino acids of laboratory rodent diets is reviewed and compared with other methods of sterilization - autoclaving and ethylene oxide fumigation. Gamma irradiation has been shown to have minimal influence on total protein, protein quality and total and available amino acid levels. Autoclaving reduces amino acid availability and consequently protein quality. Limited evidence shows reduction of certain available amino acids following ethylene oxide fumigation. (author)

  15. Production of carrier-peptide conjugates using chemically reactive unnatural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Young, Travis; Schultz, Peter G.

    2015-08-18

    Provided are methods of making carrier polypeptide that include incorporating a first unnatural amino acid into a carrier polypeptide variant, incorporating a second unnatural amino acid into a target polypeptide variant, and reacting the first and second unnatural amino acids to produce the conjugate. Conjugates produced using the provided methods are also provided. In addition, orthogonal translation systems in methylotrophic yeast and methods of using these systems to produce carrier and target polypeptide variants comprising unnatural amino acids are provided.

  16. Unusual stable isotope ratios in amino acid and carboxylic acid extracts from the Murchison meteorite

    Science.gov (United States)

    Epstein, S.; Krishnamurthy, R. V.; Cronin, J. R.; Pizzarello, S.; Yuen, G. U.

    1987-01-01

    The isotopic composition of hydrogen, nitrogen, and carbon in amino acid and monocarboxylic acid extracts from the Murchison meteorite has been determined. The unusually high D/H and N-15/N-14 ratios in the amino acid fraction are uniquely characteristic of known interstellar organic materials. The delta D value of the monocarboxylic acid fraction is lower but still consistent with an interstellar origin. These results confirm the extraterrestrial origin of both classes of compound and provide the first evidence suggesting a direct relationship between the massive organosynthesis occurring in interstellar clouds and the presence of prebiotic compounds in primitive planetary bodies.

  17. Finding coevolving amino acid residues using row and column weighting of mutual information and multi-dimensional amino acid representation

    Directory of Open Access Journals (Sweden)

    Pedersen Anders G

    2007-10-01

    Full Text Available Abstract Background Some amino acid residues functionally interact with each other. This interaction will result in an evolutionary co-variation between these residues – coevolution. Our goal is to find these coevolving residues. Results We present six new methods for detecting coevolving residues. Among other things, we suggest measures that are variants of Mutual Information, and measures that use a multidimensional representation of each residue in order to capture the physico-chemical similarities between amino acids. We created a benchmarking system, in silico, able to evaluate these methods through a wide range of realistic conditions. Finally, we use the combination of different methods as a way of improving performance. Conclusion Our best method (Row and Column Weighed Mutual Information has an estimated accuracy increase of 63% over Mutual Information. Furthermore, we show that the combination of different methods is efficient, and that the methods are quite sensitive to the different conditions tested.

  18. Free amino acids in atmospheric particulate matter of Venice, Italy

    Science.gov (United States)

    Barbaro, Elena; Zangrando, Roberta; Moret, Ivo; Barbante, Carlo; Cescon, Paolo; Gambaro, Andrea

    2011-09-01

    The concentrations of free amino acids were determined in atmospheric particulate matter from the city of Venice (Italy) in order to better understand their origin. The analysis of aerosol samples was carried out via high-performance liquid chromatography coupled to a triple quadrupole tandem mass spectrometric detector (HPLC/ESI-MS/MS). The internal standard method was used and the analytical procedure was validated by evaluating the trueness, the precision, the recovery, the detection and the quantification limits. The particulate matter was collected using quartz fiber filters and extracted in methanol; after filtration the extract was directly analyzed. Forty samples were collected from April to October 2007 and the average concentrations of free amino acids in the aerosol were: alanine 35.6 pmol m -3, aspartic acid 31.1 pmol m -3, glycine 30.1 pmol m -3, glutamic acid 32.5 pmol m -3, isoleucine 2.4 pmol m -3, leucine 2.7 pmol m -3, methionine, cystine and 3-hydroxy-proline below the limit of detection, phenylalanine 2.8 pmol m -3, proline 43.3 pmol m -3, serine 8.6 pmol m -3, threonine 2.8 pmol m -3, tyrosine 1.7 pmolm -3, valine 3.8 pmol m -3, asparagine 70.2 pmol m -3, glutamine 38.0 pmol m -3, 4-hydroxy-proline 2.5 pmol m -3, methionine sulfoxide 1.1 pmol m -3, and methionine sulfone 0.1 pmol m -3. The total average concentration of these free amino acids in aerosol samples of Venice Lagoon was 334 pmol m -3. The temporal evolution and multivariate analysis indicated the photochemical origin of 4-hydroxy-proline and methionine sulfoxide and for other compounds an origin further away from the site of sampling, presumably reflecting transport from terrestrial sources.

  19. Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, Alyssa K.; Pudritz, Ralph E., E-mail: cobbak@mcmaster.ca, E-mail: pudritz@physics.mcmaster.ca [Origins Institute, McMaster University, ABB 241, 1280 Main Street, Hamilton, ON L8S 4M1 (Canada)

    2014-03-10

    The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.

  20. Patterns of amino acid metabolism by proliferating human mesenchymal stem cells

    NARCIS (Netherlands)

    Higuera, G.A.; Schop, D.; Spitters, T.W.; Dijkhuizen, R.; Bracke, M.; Bruijn, J.D.; Martens, D.E.; Karperien, M.; Boxtel, van A.J.B.; Blitterswijk, van C.A.

    2012-01-01

    The nutritional requirements of stem cells have not been determined; in particular, the amino acid metabolism of stem cells is largely unknown. In this study, we investigated the amino acid metabolism of human mesenchymal stem cells (hMSCs), with focus on two questions: Which amino acids are consume

  1. Transition Metal–α-Amino Acid Complexes with Antibiotic Activity against Mycobacterium spp.

    OpenAIRE

    Karpin, George W.; Merola, Joseph S.; Joseph O. Falkinham

    2013-01-01

    Synthetic iridium-, rhodium-, and ruthenium-amino acid complexes with hydrophobic l-amino acids have antibiotic activity against Mycobacterium spp., including Mycobacterium bovis BCG and the rapidly growing species Mycobacterium abscessus and Mycobacterium chelonae. Concentrations of transition metal-amino acid complexes demonstrating hemolysis or cytotoxicity were 10- to 25-fold higher than were the MICs.

  2. Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

    Science.gov (United States)

    Burton, Aaron, S.; Berger, Eve L.; Locke, Darren R.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2015-01-01

    Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

  3. Identification of amino acids in Securigera securidaca, a popular medicinal herb in Iranian folk medicine

    Directory of Open Access Journals (Sweden)

    S.E. Sadat-Ebrahimi

    2014-01-01

    Full Text Available Securigera securidaca (L. Degen & Dorfl grows in different parts of Iran. The seeds of the species are used in Iranian folk medicine as an anti-diabetic agent. Many studies have established hypoglycemic effects of amino acids and in the present investigation, amino acids of Securigera securidaca seeds have been evaluated. The ground seeds were extracted using petroleum ether, hot ethanol and ethanol 50%, respectively. ethanol 50% extract was chromatographed over cation exchanging resin and the resulting amino acid fraction was subjected to HPLC after OPA derivatization and the amino acids were identified by comparing to standards. The results evidenced the presence of 19 amino acids in the plant extract including alanine, arginine, asparagine, aspartic acid, citrulline, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tyrosine and valine. Considering the role of some amino acids in diabetes the above amino acids could be noted as hypoglycemic agents of the plant seeds but further studies are necessary.

  4. Very high gravity ethanol and fatty acid production of Zymomonas mobilis without amino acid and vitamin.

    Science.gov (United States)

    Wang, Haoyong; Cao, Shangzhi; Wang, William Tianshuo; Wang, Kaven Tianyv; Jia, Xianhui

    2016-06-01

    Very high gravity (VHG) fermentation is the mainstream technology in ethanol industry, which requires the strains be resistant to multiple stresses such as high glucose concentration, high ethanol concentration, high temperature and harsh acidic conditions. To our knowledge, it was not reported previously that any ethanol-producing microbe showed a high performance in VHG fermentations without amino acid and vitamin. Here we demonstrate the engineering of a xylose utilizing recombinant Zymomonas mobilis for VHG ethanol fermentations. The recombinant strain can produce ethanol up to 136 g/L without amino acid and vitamin with a theoretical yield of 90 %, which is significantly superior to that produced by all the reported ethanol-producing strains. The intracellular fatty acids of the bacterial were about 16 % of the bacterial dry biomass, with the ratio of ethanol:fatty acids was about 273:1 (g/g). The recombinant strain was achieved by a multivariate-modular strategy tackles with the multiple stresses which are closely linked to the ethanol productivity of Z. mobilis. The over-expression of metB/yfdZ operon enabled the growth of the recombinant Z. mobilis in a chemically defined medium without amino acid and vitamin; and the fatty acids overproduction significantly increased ethanol tolerance and ethanol production. The coupled production of ethanol with fatty acids of the Z. mobilis without amino acid and vitamin under VHG fermentation conditions may permit a significant reduction of the production cost of ethanol and microbial fatty acids. PMID:27033536

  5. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    Science.gov (United States)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  6. Amino acid sequences used for clusterintg (Multi FASTA format) - Gclust Server | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available Gclust Server Amino acid sequences used for clusterintg (Multi FASTA format) Data detail Data name Amino acid sequences use... Site Policy | Contact Us Amino acid sequences used for clusterintg (Multi FASTA format) - Gclust Server | LSDB Archive ...

  7. Uric Acid Inhibits Placental System A Amino Acid Uptake☆

    OpenAIRE

    Bainbridge, S.A.; von Versen-Höynck, F.; Roberts, J M

    2008-01-01

    Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasi...

  8. Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

    Science.gov (United States)

    Weber, Arthur L.

    1998-01-01

    Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

  9. ANTIOXIDANT CAPACITY AND AMINO ACID PROFILES OF EGG TOFU

    Directory of Open Access Journals (Sweden)

    Maizura Murad

    2013-01-01

    Full Text Available Tofu contains high quality protein source and antioxidant which could reduce risk of cancer. This research aims to determine the effect of soymilk and egg ratios on the antioxidant capacity, daidzein and genistein content and amino acid profiles of egg tofu. Egg tofu was prepared using soymilk and fresh egg in ratios of 1:1, 2:1, 3:1 and 4:1. Glucono-Delta-Lactone (GDL was added in the egg tofu to act as a coagulating agent. Increased of soymilk at all ratios had significantly (p<0.05 increased in Ferric-Reducing Antioxidant Power (FRAP, daidzein and genistein content of egg tofu. Conversely, decreased in soymilk ratio had significantly (p<0.05 increased the radical scavenging activities of the 2,2-Azino-Bis 3-ethylbenzothiazoline-6-Sulfonic acid (ABTS and 2,2-Diphenyl-2-Picrylhydrazyl (DPPH in egg tofu. Increased of soymilk ratio up to 3:1 caused decreased in amino acid methionine (met and cystein (cys significantly (p<0.05. A significant (p<0.01 and a positive correlation was observed between Total Phenolic Content (TPC and FRAP (r = 0.93. However, there was a negative (p<0.01 correlation between TPC and DPPH (r = -0.83. The antioxidant capacity of egg tofu in DPPH assay showed a positive and significant (p<0.01 correlation with cysteine, methionine and tryptophan with r value of 0.92, 0.93 and 0.96 respectively. Higher content of egg in egg tofu had contributed to the increased of antioxidant capacity as indicated in DPPH assay and ABTS assay as well as amino acid methionine and cysteine.

  10. Measuring and modeling aqueous electrolyte/amino-acid solutions with ePC-SAFT

    International Nuclear Information System (INIS)

    Highlights: • Amino-acid solubilities and osmotic coefficients in ternary solutions containing one amino acids and one salt measured. • Weak salt influence on amino-acid solubilities except for salts containing Mg[2+] or NO3[−] (salting-in behavior). • Osmotic coefficients dominated by the solute with the highest molality. • Amino-acid solubilities and osmotic coefficients predicted reasonably with ePC-SAFT with deviations of 3.7% and 9.3%. • Predictions based on pure-component parameters for ions and amino acids using no ion/amino-acid fitting parameters. -- Abstract: In this work thermodynamic properties of electrolyte/amino acid/water solutions were measured and modeled. Osmotic coefficients at 298.15 K were measured by means of vapor-pressure osmometry. Amino-acid solubility at 298.15 K was determined gravimetrically. Considered aqueous systems contained one of the four amino acids: glycine, L-/DL-alanine, L-/DL-valine, and L-proline up to the respective amino-acid solubility limit and one of 13 salts composed of the ions Li+, Na+, K+, NH4+, Cl−, Br−, I−, NO3−, and SO42− at salt molalities of 0.5, 1.0, and 3.0 mol · kg−1, respectively. The data show that the salt influence is more pronounced on osmotic coefficients than on amino-acid solubility. The electrolyte Perturbed-Chain Statistical Association Theory (ePC-SAFT) was applied to model thermodynamic properties in aqueous electrolyte/amino-acid solutions. In previous works, this model had been applied to binary salt/water and binary amino acid/water systems. Without fitting any additional parameters, osmotic coefficients and amino-acid solubility in the ternary electrolyte/amino acid/water systems could be predicted with overall deviations of 3.7% and 9.3%, respectively, compared to the experimental data

  11. [Effect of proteolysis inhibitors on the incorporation of labelled amino acids into proteins].

    Science.gov (United States)

    Konikova, A S; Korotkina, R N

    1975-01-01

    Role of peptide bond breaks in the incorporation of amino acids into proteins in a "protein--amino acid" system is investigated. For this purpose the incorporation of labelled amino acids into trypsin under the inhibition of its autolysis by a specific inhibitor from soybean and epsilon-amino-caproic acid is studied. The trypsin inhibitor from soybean is found to suppress considerably the incorporation of 14C-glycine, 14C-lysine and 14C-methionine into crystal trypsin and not to affect the incorporation of labelled amino acids into chomotrypsin, papain and carboxypeptidase. Epsilon-Aminocaproic acid inhibited 14C-glycine incorporation into crystal trypsin by 40% and did not change its incorporation level into serum albumin. The dependency of amino acid incorporation level into trypsin on the activity of autolysis in the "protein--amino acid" system is demonstrated. PMID:1212456

  12. Analysis of free amino acids in green coffee beans. II. Changes of the amino acid content in arabica coffees in connection with post-harvest model treatment.

    Science.gov (United States)

    Arnold, U; Ludwig, E

    1996-10-01

    To investigate amino acid changes in green coffee beans in the post-harvest period, amino acid concentrations were determined in green beans and after modelled drying, fermentation and storage. After the drying at alternating temperatures up to maximally 40 degrees C, considerable changes in the concentrations of individual amino acids were identified. At the beginning of the storage period, significant changes in concentration were found to a minor extent. Under the condition of drying, it was mainly the concentration of glutamic acid that changed considerably. There was an increase in all the samples by 500 mg/kg dry matter on average, which corresponds to an increase of about 50% of the original value. In contrast, the concentration of aspartic acid in most of the samples decreased clearly due to drying. For the predominant part of the coffee samples, there was a significant increase in the hydrophobic amino acids Val, Phe, Ile and Leu. Changes of the quantities of other amino acids were non-uniform and only insignificant. Constant drying at 80 degrees C for most of the amino acids brought about only minor concentration changes compared to those values obtained at 40 degrees C. Modelled fermentation had no significant effect on the concentrations of the individual amino acids. After a 4-week storage of dried beans, amino acid concentrations did not change further. It is very possible that different post-harvest treatment parameters may influence the amount of aroma precursor compounds in the coffee beans. PMID:9123976

  13. The Use of Gel Electrophoresis to Study the Reactions of Activated Amino Acids with Oligonucleotides

    Science.gov (United States)

    Zieboll, Gerhard; Orgel, Leslie E.

    1994-01-01

    We have used gel electrophoresis to study the primary covalent addition of amino acids to oligonu-cleotides or their analogs and the subsequent addition of further molecules of the amino acids to generate peptides covalently linked to the oligonucleotides. We have surveyed the reactions of a variety of amino acids with the phosphoramidates derived from oligonucleotide 5 inches phosphates and ethylenediamine. We find that arginine and amino acids can interact with oligonucleotidesl through stacking interactions react most efficiently. D- and L-amino acids give indistinguishable families of products.

  14. Nitrosative stress causes amino acid auxotrophy in hmp mutant Salmonella Typhimurium.

    Science.gov (United States)

    Park, Yoon Mee; Park, Hee Jeong; Joung, Young Hee; Bang, Iel Soo

    2011-10-01

    Cytotoxic nitic oxide (NO) damages various bacterial macromolecules, resulting in abnormal metabolism by mechanisms largely unknown. We show that NO can cause amino acid auxotrophy in Salmonella Typhimurium lacking major NO-metabolizing enzyme, flavohemoglobin Hmp. In NO-producing cultures, supplementation with amino acid pool restores growth of Hmp-deficient Salmonella to normal growth phases, whereas excluding Cys or BCAA Leu, Ile, or Val from amino acid pool reduces growth recovery. Data suggest that, without detoxification, NO might inactivate key enzymes in the biosynthesis pathway of amino acids essential for Salmonella replication in amino acid-limiting host environments. PMID:21752086

  15. Copper(I) mediated cross-coupling of amino acid derived organozinc reagents with acid chlorides

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Tanner, David Ackland

    2006-01-01

    This paper describes the development of a straightforward experimental protocol for copper-mediated cross-coupling of amino acid derived beta-amido-alkylzinc iodides 1 and 3 with a range of acid chlorides. The present method uses CuCN center dot 2LiCl as the copper source and for organozinc reagent...

  16. Production of amino acids by mucor geophillus using sugar cane waste as a substrate

    International Nuclear Information System (INIS)

    In this study Mucor geophillus was used for amino acid production from acid/base hydrolysates of sugar cane bagasse. The Effects of substrate as well as influence of hydrolyzing agent on amino acid production by Mucor geophillus were investigated. Result reveals that higher amount of amino acids were accumulated when acid hydrolysates of sugar cane bagasse were used as substrate in comparison to NH/sub 4/OH and H/sub 2/O/sub 2/ hydrolysates. (author)

  17. Amino acid, fatty acid, vitamin and mineral contents of the edible garden snail (Helix aspersa)

    OpenAIRE

    Ferhat Çağıltay; (1), Nuray Erkan; Deniz Tosun; Arif Selçuk

    2011-01-01

    The nutritive and market value of meat of edible garden snail from northern Turkey was deter¬mined. Protein, fat, ash, water and carbohydrate value of edible garden snail were found 9.87, 0.58, 1.07, 82.50 and 5.99 % wet weight, respectively. The results of this study have showed that garden snails are good sources of amino acid, fatty acid, vitamins and minerals. The ly¬sine, isoleucine and leucine content from essential amino acids were 721, 467.57 and 611.50 mg/100g, respectively. The m...

  18. Design, Synthesis, and Antimycobacterial Activity of Novel Theophylline-7-Acetic Acid Derivatives With Amino Acid Moieties.

    Science.gov (United States)

    Stavrakov, Georgi; Valcheva, Violeta; Voynikov, Yulian; Philipova, Irena; Atanasova, Mariyana; Konstantinov, Spiro; Peikov, Plamen; Doytchinova, Irini

    2016-03-01

    The theophylline-7-acetic acid (7-TAA) scaffold is a promising novel lead compound for antimycobacterial activity. Here, we derive a model for antitubercular activity prediction based on 14 7-TAA derivatives with amino acid moieties and their methyl esters. The model is applied to a combinatorial library, consisting of 40 amino acid and methyl ester derivatives of 7-TAA. The best three predicted compounds are synthesized and tested against Mycobacterium tuberculosis H37Rv. All of them are stable, non-toxic against human cells and show antimycobacterial activity in the nanomolar range being 60 times more active than ethambutol. PMID:26502828

  19. Carbohydrate metabolism during prolonged exercise and recovery: interactions between pyruvate dehydrogenase, fatty acids, and amino acids

    DEFF Research Database (Denmark)

    Mourtzakis, Marina; Saltin, B.; Graham, T.;

    2006-01-01

    During prolonged exercise, carbohydrate oxidation may result from decreased pyruvate production and increased fatty acid supply and ultimately lead to reduced pyruvate dehydrogenase (PDH) activity. Pyruvate also interacts with the amino acids alanine, glutamine, and glutamate, whereby the decline...... activity (P < 0.05) and increased PDH kinase 4 mRNA (P < 0.05) during exercise and recovery. At 1 h of exercise, pyruvate production was greatest and was closely linked to glutamate, which was the predominant amino acid taken up during exercise and recovery. Alanine and glutamine were also associated with...... pyruvate metabolism, and they comprised 68% of total amino-acid release during exercise and recovery. Thus reduced pyruvate production was primarily associated with reduced carbohydrate oxidation, whereas the greatest production of pyruvate was related to glutamate, glutamine, and alanine metabolism in...

  20. Oxidation of amino acids and proteins by peroxynitrite

    International Nuclear Information System (INIS)

    Recent studies suggested that proteins exposed to free radicals and other strong oxidants generated by living organisms may be the source of damage to tissues even at sites distant from the original point of generation of the reactive species. In examining the ability of biologically significant oxidizing agents to generate protein peroxides, the authors have studied protein peroxidation by peroxynitrite (ONOO-), known to be a potential source of tissue damage. Treatment of bovine serum albumin, Iysozyme, apotransferrin, insulin or human serum albumin with peroxynitrous acid (POXNA) led to formation of hydroperoxide groups on the proteins, detected by their reaction with iodide. Under optimum conditions, up to one peroxide group formed on each molecule of protein. Hydroxyl radical scavengers, antioxidants, or metal chelators, were unable to affect the quantities of peroxides generated by POXNA. These findings suggest that the oxidation was not mediated by the hydroxyl free radicals. The iodide assay cannot be applied to the measurement of peroxides in presence of nitrite, which is a contaminant of most solutions of POXNA. Nitrite can be easily removed from proteins by molecular filtration, but this method cannot be applied to amino acids. Therefore an amino acid peroxide test based on chemiluminescence was used, which shows promise for general peroxide detection

  1. Stereoselective synthesis of uridine-derived nucleosyl amino acids.

    Science.gov (United States)

    Spork, Anatol P; Wiegmann, Daniel; Granitzka, Markus; Stalke, Dietmar; Ducho, Christian

    2011-12-16

    Novel hybrid structures of 5'-deoxyuridine and glycine were conceived and synthesized. Such nucleosyl amino acids (NAAs) represent simplified analogues of the core structure of muraymycin nucleoside antibiotics, making them useful synthetic building blocks for structure-activity relationship (SAR) studies. The key step of the developed synthetic route was the efficient and highly diastereoselective asymmetric hydrogenation of didehydro amino acid precursors toward protected NAAs. It was anticipated that the synthesis of unprotected muraymycin derivatives via this route would require a suitable intermediate protecting group at the N-3 of the uracil base. After initial attempts using PMB- and BOM-N-3 protection, both of which resulted in problematic deprotection steps, an N-3 protecting group-free route was envisaged. In spite of the pronounced acidity of the uracil-3-NH, this route worked equally efficient and with identical stereoselectivities as the initial strategies involving N-3 protection. The obtained NAA building blocks were employed for the synthesis of truncated 5'-deoxymuraymycin analogues. PMID:22059552

  2. Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles

    Science.gov (United States)

    Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...

  3. THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDS

    Institute of Scientific and Technical Information of China (English)

    MingGan; De-ChengDing; Xue-xiaMiao

    2003-01-01

    To evaluate the role of bacterial symbionts ( Buchnera spp. ) in the black bean aphids ( Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29 %, but free amino acid titers were increased by 17% . The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively,suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid,threonine represented 21. 6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition.

  4. Correlation Study on Sweetness of Amino Acid with Different Configurations and Quantum Chemical Parameters

    Institute of Scientific and Technical Information of China (English)

    LI Jun-Ling; GU Jun; QIU Guang-Min

    2006-01-01

    Quantum chemical parameters of 10 amino acids with D- and L-configurations were firstly calculated with semi-empirical AM1 method. Furthermore, the relationship between mole- cular structures of D-, L-amino acids and their sweetness were observed. The results show that upon different configurations of amino acids, the sweetness is relative with their formation heat, dipole moment, energy gap of frontier orbital and other parameters. The formation heats of the same amino acids possessing D- and L-configurations are different except glycine. The algebraic value of D- amino acid is generally larger than that of corresponding L-configuration with only one except of tyrosine. The dipole moment of D-amino acid is generally larger than that of corresponding L-amino acid except tyrosine and lysine. The lowest unoccupied orbital energy (ELUMO) of D-amino acid is higher than that of corresponding L-configuration except phenylalanine. △E of D-amino acid is larger than that of L-amino acid except histidine, phenylalanine and lysine. The larger gap will have advantage for its matching with frontier orbital energy of human protein acceptor, which strengthens the interaction between D-amino acid and sweet taste acceptor. Besides, the changing rules of these parameters are generally identical.

  5. Branched-chain amino acids and brain function.

    Science.gov (United States)

    Fernstrom, John D

    2005-06-01

    Branched-chain amino acids (BCAAs) influence brain function by modifying large, neutral amino acid (LNAA) transport at the blood-brain barrier. Transport is shared by several LNAAs, notably the BCAAs and the aromatic amino acids (ArAAs), and is competitive. Consequently, when plasma BCAA concentrations rise, which can occur in response to food ingestion or BCAA administration, or with the onset of certain metabolic diseases (e.g., uncontrolled diabetes), brain BCAA concentrations rise, and ArAA concentrations decline. Such effects occur acutely and chronically. Such reductions in brain ArAA concentrations have functional consequences: biochemically, they reduce the synthesis and the release of neurotransmitters derived from ArAAs, notably serotonin (from tryptophan) and catecholamines (from tyrosine and phenylalanine). The functional effects of such neurochemical changes include altered hormonal function, blood pressure, and affective state. Although the BCAAs thus have biochemical and functional effects in the brain, few attempts have been made to characterize time-course or dose-response relations for such effects. And, no studies have attempted to identify levels of BCAA intake that might produce adverse effects on the brain. The only "model" of very high BCAA exposure is a very rare genetic disorder, maple syrup urine disease, a feature of which is substantial brain dysfunction but that probably cannot serve as a useful model for excessive BCAA intake by normal individuals. Given the known biochemical and functional effects of the BCAAs, it should be a straightforward exercise to design studies to assess dose-response relations for biochemical and functional effects and, in this context, to explore for adverse effect thresholds. PMID:15930466

  6. UTILIZATION OF AMINO ACIDS OF BROKEN RICE IN GROWING PIGS

    Directory of Open Access Journals (Sweden)

    Matej Brestenský

    2014-02-01

    Full Text Available The six cannulated gilts (initial body weight 35.8 ± 0.5 kg fitted with a T-cannula in terminal ileum, were used to determine the apparent (AID and standardized (SID ileal digestibility of nitrogen (N and amino acids (AA in broken rice. Animals were fed twice daily in a two equal doses at a daily rate of 80 g.kg - 0.75. Water was offered ad libitum. The tested feed was the sole source of protein in the diet. The N-free diet was used to determine the ileal endogenous flow of AA and N. Chromium oxide (Cr2O3 was added to the diets as an indigestible marker in an amount of 0.3 % per kg of diet. After a 14 d postoperative period a 6 d adaptation period followed during which the animals were fed with an experimental diet. On d 7 ileal digesta was collected continuously for 24 h. The AID and SID of AA and N were calculated using analytically determined values of N, Cr2O3 and AA. The SID of AA was in a range from 81.6 % (tyrosine to 112.6 % (proline (P 0.05, respectively. There were no differences between standardized ileal digestibility of essential amino acids (94.3 % and nonessential amino acids (95.3 %. Regarding the ileal digestibility of AA, broken rice, a by-product from the food industry, is an appropriate source of digestible AA for growing pigs.

  7. Hyperdimensional analysis of amino acid pair distributions in proteins.

    Directory of Open Access Journals (Sweden)

    Svend B Henriksen

    Full Text Available Our manuscript presents a novel approach to protein structure analyses. We have organized an 8-dimensional data cube with protein 3D-structural information from 8706 high-resolution non-redundant protein-chains with the aim of identifying packing rules at the amino acid pair level. The cube contains information about amino acid type, solvent accessibility, spatial and sequence distance, secondary structure and sequence length. We are able to pose structural queries to the data cube using program ProPack. The response is a 1, 2 or 3D graph. Whereas the response is of a statistical nature, the user can obtain an instant list of all PDB-structures where such pair is found. The user may select a particular structure, which is displayed highlighting the pair in question. The user may pose millions of different queries and for each one he will receive the answer in a few seconds. In order to demonstrate the capabilities of the data cube as well as the programs, we have selected well known structural features, disulphide bridges and salt bridges, where we illustrate how the queries are posed, and how answers are given. Motifs involving cysteines such as disulphide bridges, zinc-fingers and iron-sulfur clusters are clearly identified and differentiated. ProPack also reveals that whereas pairs of Lys residues virtually never appear in close spatial proximity, pairs of Arg are abundant and appear at close spatial distance, contrasting the belief that electrostatic repulsion would prevent this juxtaposition and that Arg-Lys is perceived as a conservative mutation. The presented programs can find and visualize novel packing preferences in proteins structures allowing the user to unravel correlations between pairs of amino acids. The new tools allow the user to view statistical information and visualize instantly the structures that underpin the statistical information, which is far from trivial with most other SW tools for protein structure analysis.

  8. Imputing amino acid polymorphisms in human leukocyte antigens.

    Directory of Open Access Journals (Sweden)

    Xiaoming Jia

    Full Text Available DNA sequence variation within human leukocyte antigen (HLA genes mediate susceptibility to a wide range of human diseases. The complex genetic structure of the major histocompatibility complex (MHC makes it difficult, however, to collect genotyping data in large cohorts. Long-range linkage disequilibrium between HLA loci and SNP markers across the major histocompatibility complex (MHC region offers an alternative approach through imputation to interrogate HLA variation in existing GWAS data sets. Here we describe a computational strategy, SNP2HLA, to impute classical alleles and amino acid polymorphisms at class I (HLA-A, -B, -C and class II (-DPA1, -DPB1, -DQA1, -DQB1, and -DRB1 loci. To characterize performance of SNP2HLA, we constructed two European ancestry reference panels, one based on data collected in HapMap-CEPH pedigrees (90 individuals and another based on data collected by the Type 1 Diabetes Genetics Consortium (T1DGC, 5,225 individuals. We imputed HLA alleles in an independent data set from the British 1958 Birth Cohort (N = 918 with gold standard four-digit HLA types and SNPs genotyped using the Affymetrix GeneChip 500 K and Illumina Immunochip microarrays. We demonstrate that the sample size of the reference panel, rather than SNP density of the genotyping platform, is critical to achieve high imputation accuracy. Using the larger T1DGC reference panel, the average accuracy at four-digit resolution is 94.7% using the low-density Affymetrix GeneChip 500 K, and 96.7% using the high-density Illumina Immunochip. For amino acid polymorphisms within HLA genes, we achieve 98.6% and 99.3% accuracy using the Affymetrix GeneChip 500 K and Illumina Immunochip, respectively. Finally, we demonstrate how imputation and association testing at amino acid resolution can facilitate fine-mapping of primary MHC association signals, giving a specific example from type 1 diabetes.

  9. The contribution of SNAT1 to system A amino acid transporter activity in human placental trophoblast

    International Nuclear Information System (INIS)

    Research highlights: → mRNA levels for SNAT1 are higher than other system A subtype mRNAs in primary human cytotrophoblast. → SNAT1 knockdown in cytotrophoblast cells significantly reduces system A activity. → SNAT1 is a key contributor to system A-mediated amino acid transport in human placenta. -- Abstract: System A-mediated amino acid transport across the placenta is important for the supply of neutral amino acids needed for fetal growth. All three system A subtypes (SNAT1, 2, and 4) are expressed in human placental trophoblast suggesting there is an important biological role for each. Placental system A activity increases as pregnancy progresses, coinciding with increased fetal nutrient demands. We have previously shown SNAT4-mediated system A activity is higher in first trimester than at term, suggesting that SNAT1 and/or SNAT2 are responsible for the increased system A activity later in gestation. However, the relative contribution of each subtype to transporter activity in trophoblast at term has yet to be evaluated. The purpose of this study was to identify the predominant subtype of system A in cytotrophoblast cells isolated from term placenta, maintained in culture for 66 h, by: (1) measuring mRNA expression of the three subtypes and determining the Michaelis-Menten constants for uptake of the system A-specific substrate, 14C-MeAIB, (2) investigating the contribution of SNAT1 to total system A activity using siRNA. Results: mRNA expression was highest for the SNAT1 subtype of system A. Kinetic analysis of 14C-MeAIB uptake revealed two distinct transport systems; system 1: Km = 0.38 ± 0.12 mM, Vmax = 27.8 ± 9.0 pmol/mg protein/20 min, which resembles that reported for SNAT1 and SNAT2 in other cell types, and system 2: Km = 45.4 ± 25.0 mM, Vmax = 1190 ± 291 pmol/mg protein/20 min, which potentially represents SNAT4. Successful knockdown of SNAT1 mRNA using target-specific siRNA significantly reduced system A activity (median 75% knockdown, n = 7

  10. Heterodimeric l-amino acid oxidase enzymes from Egyptian Cerastes cerastes venom: Purification, biochemical characterization and partial amino acid sequencing

    Directory of Open Access Journals (Sweden)

    A.E. El Hakim

    2015-12-01

    Full Text Available Two l-amino acid oxidase enzyme isoforms, Cc-LAAOI and Cc-LAAOII were purified to apparent homogeneity from Cerastes cerastes venom in a sequential two-step chromatographic protocol including; gel filtration and anion exchange chromatography. The native molecular weights of the isoforms were 115 kDa as determined by gel filtration on calibrated Sephacryl S-200 column, while the monomeric molecular weights of the enzymes were, 60, 56 kDa and 60, 53 kDa for LAAOI and LAAOII, respectively. The tryptic peptides of the two isoforms share high sequence homology with other snake venom l-amino acid oxidases. The optimal pH and temperature values of Cc-LAAOI and Cc-LAAOII were 7.8, 50 °C and 7, 60 °C, respectively. The two isoenzymes were thermally stable up to 70 °C. The Km and Vmax values were 0.67 mM, 0.135 μmol/min for LAAOI and 0.82 mM, 0.087 μmol/min for LAAOII. Both isoenzymes displayed high catalytic preference to long-chain, hydrophobic and aromatic amino acids. The Mn2+ ion markedly increased the LAAO activity for both purified isoforms, while Na+, K+, Ca2+, Mg2+ and Ba2+ ions showed a non-significant increase in the enzymatic activity of both isoforms. Furthermore, Zn2+, Ni2+, Co2+, Cu2+ and AL3+ ions markedly inhibited the LAAOI and LAAOII activities. l-Cysteine and reduced glutathione completely inhibited the LAAO activity of both isoenzymes, whereas, β-mercaptoethanol, O-phenanthroline and PMSF completely inhibited the enzymatic activity of LAAOII. Furthermore, iodoacitic acid inhibited the enzymatic activity of LAAOII by 46% and had no effect on the LAAOI activity.

  11. Nature's Starships. I. Observed Abundances and Relative Frequencies of Amino Acids in Meteorites

    CERN Document Server

    Cobb, Alyssa K

    2014-01-01

    The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. The...

  12. Intravenous lipid and amino acids briskly increase plasma glucose concentrations in small premature infants.

    Science.gov (United States)

    Savich, R D; Finley, S L; Ogata, E S

    1988-07-01

    We determined the glycemic response to intravenous lipid infusion alone, lipid with amino acids, or amino acids alone in 15 very small premature infants receiving constant glucose infusion during early life. Infants who received lipid or lipid and amino acids demonstrated significant increases in glucose compared with infants who received amino acids. The combination of lipid and amino acids resulted in an earlier increase than lipid alone. Although plasma insulin did not change in all three groups, infants who received amino acids alone demonstrated an appropriate increase in glucagon. These data suggest that lipid infusion, a commonly used means of providing nutrition to premature infants, may cause significant disturbances in glucoregulation, particularly when administered with amino acids. PMID:3132930

  13. A thermodynamic basis for prebiotic amino acid synthesis and the nature of the first genetic code

    CERN Document Server

    Higgs, Paul G

    2009-01-01

    Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

  14. Free amino acid composition of quince (Cydonia oblonga Miller) fruit (pulp and peel) and jam.

    Science.gov (United States)

    Silva, Branca M; Casal, Susana; Andrade, Paula B; Seabra, Rosa M; Oliveira, M Beatriz P P; Ferreira, Margarida A

    2004-03-10

    Twenty-one free amino acids present in several samples of quince fruit (pulp and peel) and quince jam (homemade and industrially manufactured) were analyzed by GC/FID. The analyses showed some differences between quince pulps and peels. Generally, the highest content in total free amino acids and in glycine was found in peels. As a general rule, the three major free amino acids detected in pulps were aspartic acid, asparagine, and hydroxyproline. For quince peels, usually, the three most abundant amino acids were glycine, aspartic acid, and asparagine. Similarly, for quince jams the most important free amino acids were aspartic acid, asparagine, and glycine or hydroxyproline. This study suggests that the free amino acid analysis can be useful for the evaluation of quince jam authenticity. It seems that glycine percentage can be used for the detection of quince peel addition while high alanine content can be related to pear addition. PMID:14995121

  15. On Quantum Algorithm for Multiple Alignment of Amino Acid Sequences

    Science.gov (United States)

    Iriyama, Satoshi; Ohya, Masanori

    2009-02-01

    The alignment of genome sequences or amino acid sequences is one of fundamental operations for the study of life. Usual computational complexity for the multiple alignment of N sequences with common length L by dynamic programming is O(LN). This alignment is considered as one of the NP problems, so that it is desirable to find a nice algorithm of the multiple alignment. Thus in this paper we propose the quantum algorithm for the multiple alignment based on the works12,1,2 in which the NP complete problem was shown to be the P problem by means of quantum algorithm and chaos information dynamics.

  16. CHOICE FEEDING AND AMINO ACID REQUIREMENTS FOR BROILERS

    OpenAIRE

    B. Indarsih; R.A.E.Pym

    2011-01-01

    The study was conducted as a completely randomized design, with a factorial arrangement to determine the response of commercial broilers to choice feeding and limiting amino acids on growth and carcass performance. A total of 432 male birds were weighed at one-d-old and randomly distributed to 48 wire-floored brooder cage each 1.0 m2. There were 2 sexes and 4 dietary treatments with 6 replicates each of 9 birds. Birds were given one of three dietary regimens with dietary change every 7 days. ...

  17. Dietary amino acid-induced systemic lupus erythematosus.

    Science.gov (United States)

    Montanaro, A; Bardana, E J

    1991-05-01

    The effects of dietary manipulations on autoimmune disease are understood poorly. In this article, we detail our experience with a human subject who developed autoimmune hemolytic anemia while participating in a research study that required the ingestion of alfalfa seeds. Subsequent experimental studies in primates ingesting alfalfa sprout seeds and L-canavanine (a prominent amino acid constituent of alfalfa) is presented. The results of these studies indicate a potential toxic and immunoregulatory role of L-canavanine in the induction of a systemic lupus-like disease in primates. PMID:1862241

  18. Metal-based chemosensors for amino acids, peptides, and nucleotides

    OpenAIRE

    Buryak, Andrey

    2007-01-01

    An organometallic 4d transition metal complex [Cp*RhCl2]2, together with commercially available dyes, was used to construct indicator displacement assays (IDAs) for the detection of peptides, amino acids, and nucleotides. The combination of the Cp*Rh complex with the dye azophloxine was found to form a chemosensing ensemble for the sequence-selective detection of histidine- and methionine-containing peptides in water at neutral pH. A strong interaction of the rhodium complex with peptides bea...

  19. Metal-based chemosensors for amino acids, peptides, and nucleotides

    OpenAIRE

    Buryak, Andrey; Severin, Kay

    2008-01-01

    An organometallic 4d transition metal complex [Cp*RhCl2]2, together with commercially available dyes, was used to construct indicator displacement assays (IDAs) for the detection of peptides, amino acids, and nucleotides. The combination of the Cp*Rh complex with the dye azophloxine was found to form a chemosensing ensemble for the sequence-selective detection of histidine- and methionine-containing peptides in water at neutral pH. A strong interaction of the rhodium complex with peptides bea...

  20. Induction of DNA damage by oxidised amino acids and proteins

    DEFF Research Database (Denmark)

    Luxford, Catherine; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    Exposure of amino acids, peptides and proteins to radicals in the presence of O2 generates hydroperoxides in a dose-dependent manner. These hydroperoxides are stable in the absence of exogenous catalysts (e.g. heat, light, redox-active transition metal ions), but decompose rapidly in the presence...... of these agents to give a variety of radicals including alkoxyl (RO*), peroxyl (ROO*) and carbon-centred (R) species. These radicals are shown to react with DNA to give DNA-protein cross-links and single strand breaks....

  1. Scaffolding along Nucleic Acid Duplexes Using 2'-Amino-Locked Nucleic Acids

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Wengel, Jesper

    2014-01-01

    '-amino-LNA nucleotides. By application of different chemical reactions, modification of 2'-amino-LNA scaffolds can be efficiently performed in high yields and with various tags, postsynthetically or during the automated oligonucleotide synthesis. The choice of a synthetic method for scaffolding along 2......Conspectus Incorporation of chemically modified nucleotide scaffolds into nucleic acids to form assemblies rich in function is an innovative area with great promise for nanotechnology and biomedical and material science applications. The intrinsic biorecognition potential of nucleic acids combined......'-amino-LNA mainly depends on the chemical nature of the modification, its price, its availability, and applications of the product. One of the most useful applications of the product LNA/DNA scaffolds containing 2'-amino-LNA is to detect complementary DNA and RNA targets. Examples of these applications...

  2. An Experimental Styudy on Gold Solubility in Amino Acid Solution and Its Geological Significance

    Institute of Scientific and Technical Information of China (English)

    张景荣; 陆建军; 等

    1996-01-01

    The experiments on gold solubility in amino acid solution mdicate that gold is very intensively soluble in amino acid(or other organic acids),which is extensively present in geological bodies,and is most soluble in histidine.The temperature and concentration,acidity and type of amino acid in the solution are important factors affecting gold-amino acid complexing. The solubility of gold in amino acid is different under different conditions of temperature, amino acid concentration and pH value of the solution,At 80℃ and pH=6-8,gold is most soluble in amino acid.Gold dispersed in water and rocks could be concentrated and transported by amino acid and then precipitated in favorable loci.Amino acids might have played an important role in metallogenesis as well as in the formation of source beds of gold.Nitrogen,oxygen and sulfur in amino acid might have reacted with gold to form soluble complex ions.

  3. Improving the Reliability of Optimal In-Feed Amino Acid Ratios Based on Individual Amino Acid Efficiency Data from N Balance Studies in Growing Chicken

    Directory of Open Access Journals (Sweden)

    Frank Liebert

    2013-06-01

    Full Text Available Three consecutive nitrogen balance experiments with fast-growing male broiler chickens (ROSS 308, both during starter and grower periods, were conducted to determine the ideal ratios of several indispensable amino acids relative to lysine. The control diets based on corn, wheat, fishmeal, field peas, wheat gluten and soybean oil were formulated by computer optimizing to meet the assumed ideal amino acid ratios and to fulfill both the energy and nutrient requirements of growing chicken. According to principles of the diet dilution technique, balanced control diets were diluted by wheat starch and refilled by crystalline amino acids and remaining feed ingredients, except the amino acid under study. The lysine, threonine, tryptophan, arginine, isoleucine and valine diluted diets resulted in significantly lower protein quality as compared to control diet, especially following increased dietary lysine supply (experiments II and III and stronger amino acid dilution (experiment III. Accordingly, the limiting position of individual amino acids was confirmed, and the derived amino acid efficiency data were utilized to derive ideal amino acid ratios for the starter period: Lys (100: Thr (60: Trp (19: Arg (105: Ile (55: Val (63; and the grower period: Lys (100: Thr (62: Trp (17: Arg (105: Ile (65: Val (79.

  4. Improving the Reliability of Optimal In-Feed Amino Acid Ratios Based on Individual Amino Acid Efficiency Data from N Balance Studies in Growing Chicken.

    Science.gov (United States)

    Wecke, Christian; Liebert, Frank

    2013-01-01

    Three consecutive nitrogen balance experiments with fast-growing male broiler chickens (ROSS 308), both during starter and grower periods, were conducted to determine the ideal ratios of several indispensable amino acids relative to lysine. The control diets based on corn, wheat, fishmeal, field peas, wheat gluten and soybean oil were formulated by computer optimizing to meet the assumed ideal amino acid ratios and to fulfill both the energy and nutrient requirements of growing chicken. According to principles of the diet dilution technique, balanced control diets were diluted by wheat starch and refilled by crystalline amino acids and remaining feed ingredients, except the amino acid under study. The lysine, threonine, tryptophan, arginine, isoleucine and valine diluted diets resulted in significantly lower protein quality as compared to control diet, especially following increased dietary lysine supply (experiments II and III) and stronger amino acid dilution (experiment III). Accordingly, the limiting position of individual amino acids was confirmed, and the derived amino acid efficiency data were utilized to derive ideal amino acid ratios for the starter period: Lys (100): Thr (60): Trp (19): Arg (105): Ile (55): Val (63); and the grower period: Lys (100): Thr (62): Trp (17): Arg (105): Ile (65): Val (79). PMID:26479521

  5. Spodoptera littoralis detoxifies neurotoxic 3-nitropropanoic acid by conjugation with amino acids.

    Science.gov (United States)

    Novoselov, Alexey; Becker, Tobias; Pauls, Gerhard; von Reuß, Stephan H; Boland, Wilhelm

    2015-08-01

    Spodoptera littoralis is a phytophagous generalist. Its host range includes more than 40 plant species, some of which produce 3-nitropropanoic acid (3-NPA), an irreversible inhibitor of mitochondrial succinate dehydrogenase. Growth in larvae fed an artificial diet with a sublethal admixture of 3-NPA (4.2 μmol per g) was slowed significantly, but larvae experienced no increase in mortality. In contrast, larvae injected with 25.2 μmol/g (bodyweight) 3-NPA experienced acute toxicity and death. To study the detoxification mechanism of 3-NPA in S. littoralis, the insect frass was analyzed by HPLC-MS. Comparative analysis of 3-NPA-treated and -untreated control samples using HR-MS(2) revealed a group of differential signals that were identified as amino acid amides of 3-NPA with glycine, alanine, serine, and threonine. When sublethal amounts of stable isotope-labeled 3-NPA were injected into a larva's hemolymph, 3-NPA amino acid conjugates were identified as putative detoxification products. Bioassays with synthetic standards confirmed that the toxicity of the amides was negligible in comparison to the toxicity of free 3-NPA, demonstrating that amino acid conjugation in S. littoralis represents an efficient way to detoxify 3-NPA. Furthermore, biosynthetic studies using crude fractions of the gut tissue indicated that conjugation of 3-NPA with amino acids occurs in epithelial cells of the insect's gut. Taken together, these results suggest that the detoxification of 3-NPA in S. littoralis proceeds via conjugation to specific amino acids within the epithelial cells followed by export of the nontoxic amino acid conjugates to the hemolymph via as yet uncharacterized mechanisms, most likely involving the Malpighian tubules. PMID:26092560

  6. Conserved charged amino acid residues in the extracellular region of sodium/iodide symporter are critical for iodide transport activity

    Directory of Open Access Journals (Sweden)

    Liang Ji-An

    2010-11-01

    Full Text Available Abstract Background Sodium/iodide symporter (NIS mediates the active transport and accumulation of iodide from the blood into the thyroid gland. His-226 located in the extracellular region of NIS has been demonstrated to be critical for iodide transport in our previous study. The conserved charged amino acid residues in the extracellular region of NIS were therefore characterized in this study. Methods Fourteen charged residues (Arg-9, Glu-79, Arg-82, Lys-86, Asp-163, His-226, Arg-228, Asp-233, Asp-237, Arg-239, Arg-241, Asp-311, Asp-322, and Asp-331 were replaced by alanine. Iodide uptake abilities of mutants were evaluated by steady-state and kinetic analysis. The three-dimensional comparative protein structure of NIS was further modeled using sodium/glucose transporter as the reference protein. Results All the NIS mutants were expressed normally in the cells and targeted correctly to the plasma membrane. However, these mutants, except R9A, displayed severe defects on the iodide uptake. Further kinetic analysis revealed that mutations at conserved positively charged amino acid residues in the extracellular region of NIS led to decrease NIS-mediated iodide uptake activity by reducing the maximal rate of iodide transport, while mutations at conserved negatively charged residues led to decrease iodide transport by increasing dissociation between NIS mutants and iodide. Conclusions This is the first report characterizing thoroughly the functional significance of conserved charged amino acid residues in the extracellular region of NIS. Our data suggested that conserved charged amino acid residues, except Arg-9, in the extracellular region of NIS were critical for iodide transport.

  7. Amino acid, fatty acid, vitamin and mineral contents of the edible garden snail (Helix aspersa

    Directory of Open Access Journals (Sweden)

    Ferhat Çağıltay

    2011-10-01

    Full Text Available The nutritive and market value of meat of edible garden snail from northern Turkey was deter¬mined. Protein, fat, ash, water and carbohydrate value of edible garden snail were found 9.87, 0.58, 1.07, 82.50 and 5.99 % wet weight, respectively. The results of this study have showed that garden snails are good sources of amino acid, fatty acid, vitamins and minerals. The ly¬sine, isoleucine and leucine content from essential amino acids were 721, 467.57 and 611.50 mg/100g, respectively. The major amino acids detected were aspartic acid (996.814 mg/100g, glutamic acid (1405.158 mg/100g, alanine (1063.877 mg/100g, serine (1039.248 mg/100g. Total saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid were de¬termined 28, 76, 20.66 and 34.38 %. The vitamin A, vitamin E, vitamin B1, B2, B3 and B6 of vitamins were 5.462, 0.887, 0.154, 0.065, 3.226 and 0.288 mg/100g wet wt, respectively. Min¬eral analysis of garden snails showed that they are rich in calcium and potassium (1357 and 1054 mg/kg and low in iron (5.21 mg/kg.

  8. Synthesis and biodistribution of six novel 99mTc complexes of 2-hydroxybenzaldehyde-amino acid Schiff bases

    International Nuclear Information System (INIS)

    For the purpose of developing novel diagnostic pharmaceuticals of 99mTc-labeled small-size complexes, six novel complexes of 99mTc-2-hydroxybenzaldehyde-amino acid Schiff bases were designed and synthesized, and their biodistributions in mice were investigated. All the compounds were obtained in radiochemical yields higher than 90% at optimal conditions, and poor uptakes in muscle, brain, heart and tumor were commonly observed with rapid blood clearance. Potentiality was revealed of good kidney imaging by 2-hydroxybenzaldehyde-alanine (L2) complex within 40 min post-injection. Good bone uptake of 2-hydroxybenzaldehyde-histidine (L4) and 2-hydroxybenzaldehyde-aspartic acid (L5) complexes, high spleen accumulation of 2-hydroxybenzaldehyde-glycine (L1) and 2-hydroxybenzaldehyde-cysteine (L3) complexes, and non-specific biodistribution of 2-hydroxybenzaldehyde-glutamic acid (L6) complex were demonstrated

  9. Preparation and Properties of Vesicles from Condensable Amphiphilic Amino Acids

    Institute of Scientific and Technical Information of China (English)

    熊向源; 何巍; 李子臣; 李福绵

    2001-01-01

    Three double-chain amphiphiles with amino acid groups as hydrphilic moiety were synthesized. These amphiphiles can be easily dispersed in buffer solution to form transparent dispersion. Examination of the dispersion by transmission electron microscopy (TEM) showed the formation of stable vesicular aggregates, which was also confirmed by the ability to encapsulate water-soluble dyes. Since amino acid groups are located on the surface of the vesicles, water-soluble carbodiimide can induce the condensation of these groups to form peptide. The phase transition temperatures of these vesicles were estimated by differential scanning calorimetry (DSC), and a decrease of phase transition temperature was observed after polycondensation due to the disturbance of the ordered arrangement of the hydrophobic chains. The leakage rate of the vesicles before and after condensation was studied by monitoring the increase of fluorescence intensity of water-soluble dye. These vesicles belong to the least permeable ones and the leakage rate can be controlled by varying the degree of condensation or the temperature.

  10. Cometary impact and amino acid survival - Chemical kinetics and thermochemistry

    Science.gov (United States)

    Ross, D.S.

    2006-01-01

    The Arrhenius parameters for the initiating reactions in butane thermolysis and the formation of soot, reliable to at least 3000 K, have been applied to the question of the survival of amino acids in cometary impacts on early Earth. The pressure/temperature/time course employed here was that developed in hydrocode simulations for kilometer-sized comets (Pierazzo and Chyba, 1999), with attention to the track below 3000 K where it is shown that potential stabilizing effects of high pressure become unimportant kinetically. The question of survival can then be considered without the need for assignment of activation volumes and the related uncertainties in their application to extreme conditions. The exercise shows that the characteristic times for soot formation in the interval fall well below the cooling periods for impacts ranging from fully vertical down to about 9?? above horizontal. Decarboxylation, which emerges as more rapid than soot formation below 2000-3000 K, continues further down to extremely narrow impact angles, and accordingly cometa??ry delivery of amino acids to early Earth is highly unlikely. ?? 2006 American Chemical Society.

  11. Neutral amino acid transport across brain microvessel endothelial cell monolayers

    International Nuclear Information System (INIS)

    Brain microvessel endothelial cells (BMEC) which form the blood-brain barrier (BBB) possess an amino acid carrier specific for large neutral amino acids (LNAA). The carrier is important for facilitating the delivery of nutrient LNAA's and centrally acting drugs that are LNAA's, to the brain. Bovine BMEC's were isolated and grown up to complete monolayers on regenerated cellulose-membranes in primary culture. To study the transendothelial transport of leucine, the monolayers were placed in a side-by-side diffusion cell, and transport across the monolayers followed with [3H]-leucine. The transendothelial transport of leucine in this in vitro model was determined to be bidirectional, and time-, temperature-, and concentration-dependent. The transport of leucine was saturable and the apparent K/sub m/ and V/sub max/, 0.18 mM and 6.3 nmol/mg/min, respectively. Other LNAA's, including the centrally acting drugs, α-methyldopa, L-DOPA, α-methyl-tyrosine, and baclofen, inhibited leucine transport. The leucine carrier was also found to be stereospecific and not sensitive to inhibitors of active transport. These results are consistent with previous in vitro and in vivo studies. Primary cultures of BMEC's appear to be a potentially important tool for investigating at the cellular level, the transport mechanisms of the BBB

  12. Neutral amino acid transport across brain microvessel endothelial cell monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Audus, K.L.; Borchardt, R.T.

    1986-03-01

    Brain microvessel endothelial cells (BMEC) which form the blood-brain barrier (BBB) possess an amino acid carrier specific for large neutral amino acids (LNAA). The carrier is important for facilitating the delivery of nutrient LNAA's and centrally acting drugs that are LNAA's, to the brain. Bovine BMEC's were isolated and grown up to complete monolayers on regenerated cellulose-membranes in primary culture. To study the transendothelial transport of leucine, the monolayers were placed in a side-by-side diffusion cell, and transport across the monolayers followed with (/sup 3/H)-leucine. The transendothelial transport of leucine in this in vitro model was determined to be bidirectional, and time-, temperature-, and concentration-dependent. The transport of leucine was saturable and the apparent K/sub m/ and V/sub max/, 0.18 mM and 6.3 nmol/mg/min, respectively. Other LNAA's, including the centrally acting drugs, ..cap alpha..-methyldopa, L-DOPA, ..cap alpha..-methyl-tyrosine, and baclofen, inhibited leucine transport. The leucine carrier was also found to be stereospecific and not sensitive to inhibitors of active transport. These results are consistent with previous in vitro and in vivo studies. Primary cultures of BMEC's appear to be a potentially important tool for investigating at the cellular level, the transport mechanisms of the BBB.

  13. The amino-acid sequence of kangaroo pancreatic ribonuclease.

    Science.gov (United States)

    Gaastra, W; Welling, G W; Beintema, J J

    1978-05-01

    Red kangaroo (Macropus rufus) ribonuclease was isolated from pancreatic tissue by affinity chromatography. The amino acid sequence was determined by automatic sequencing of overlapping large fragments and by analysis of shorter peptides obtained by digestion with a number of proteolytic enzymes. The polypeptide chain consists of 122 amino acid residues. Compared to other ribonucleases, the N-terminal residue and residue 114 are deleted. In other pancreatic ribonucleases position 114 is occupied by a cis proline residue in an external loop at the surface of the molecule. Other remarkable substitutions are the presence of a tyrosine residue at position 123 instead of a serine which forms a hydrogen bond with the pyrimidine ring of a nucleotide substrate, and a number of hydrophobichydrophilic interchanges in the sequence 51-55, which forms part of an alpha-helix in bovine ribonuclease and exhibits few substitutions in the placental mammals. Kangaroo ribonuclease contains no carbohydrate, although the enzyme possesses a recognition site for carbohydrate attachment in the sequence Asn-Val-Thr (62-64). The enzyme differs at about 35-40% of the positions from all other mammalian pancreatic ribonucleases sequenced to date, which is in agreement with the early divergence between the marsupials and the placental mammals. From fragmentary data a tentative sequence of red-necked wallaby (Macropus rufogriseus) pancreatic ribonuclease has been derived. Eight differences with the kangaroo sequence were found. PMID:658039

  14. UV-resonance Raman spectroscopy of amino acids

    Science.gov (United States)

    Höhl, Martin; Meinhardt-Wollweber, Merve; Schmitt, Heike; Lenarz, Thomas; Morgner, Uwe

    2016-03-01

    Resonant enhancement of Raman signals is a useful method to increase sensitivity in samples with low concentration such as biological tissue. The investigation of resonance profiles shows the optimal excitation wavelength and yields valuable information about the molecules themselves. However careful characterization and calibration of all experimental parameters affecting quantum yield is required in order to achieve comparability of the single spectra recorded. We present an experimental technique for measuring the resonance profiles of different amino acids. The absorption lines of these molecules are located in the ultraviolet (UV) wavelength range. One limitation for broadband measurement of resonance profiles is the limited availability of Raman filters in certain regions of the UV for blocking the Rayleigh scattered light. Here, a wavelength range from 244.8 nm to 266.0 nm was chosen. The profiles reveal the optimal wavelength for recording the Raman spectra of amino acids in aqueous solutions in this range. This study provides the basis for measurements on more complex molecules such as proteins in the human perilymph. The composition of this liquid in the inner ear is essential for hearing and cannot be analyzed non-invasively so far. The long term aim is to implement this technique as a fiber based endoscope for non-invasive measurements during surgeries (e. g. cochlear implants) making it available as a diagnostic tool for physicians. This project is embedded in the interdisciplinary cluster of excellence "Hearing for all" (H4A).

  15. Interaction of basic amino acids, polypeptides and proteins with heparin

    International Nuclear Information System (INIS)

    A study has been made of the relative binding affinities for heparin of L-lysine, L-arginine, poly-L-lysine, poly-L-arginine, protamine, thrombin and antithrombin III. The destruction by different concentrations of organic cations of the heparin-methylene blue complex was determined by visible absorption spectroscopy. The strength of binding of the basic amino acids and polypeptides increased with increasing molecular weight, and decreased at low pH. Pulse radiolysis experiments were used to show the effects of increasing concentrations of L-lysine, poly-L-lysine and protamine sulphate on the reaction of e-sub(aq) with the heparin-methylene blue complex. The results indicate that the binding of basic amino acids and polypeptides to heparin is ionic, and that the enhanced rate of association of antithrombin III to thrombin in the presence of heparin is due to partial or complete charge neutralization of the basic groups in the proteins. (U.K.)

  16. Tumor-targeted boron-containing amino acids and their related compounds. Synthesis and biological activity

    International Nuclear Information System (INIS)

    In a series of our synthetic studies on boron-containing amino acids and their related compounds for BNCT (Boron Neutron Capture Therapy), p-boronophenylalanine (BPA), p-boronophenylserine (BPS), o-carboranylmethyl-3-hydroxytyrosine (CMHT) and their derivatives were designed and synthesized by using of isocyano compounds as a starting material. Two water-soluble amino alcohols, BPA-OH and BPS-OH, were prepared by the reduction of the corresponding N-formyl amino esters. On the other hand, CMHTA, an amide derivative of CMHT, was synthesized by an aldol-type condensation of isocyanoacetamide with 4-(o-carboranylmethyloxy)benz aldehyde as a key reaction. The relative tumor cell (human glioma T98G) killing effect of nBPS-OH, nBPA-OH and CMHTA against 10BPA was 0.7, 1.0 and 4.9, respectively. The uptake of CMHTA by the tumor cell increased with increasing cultivation time. (J.P.N.)

  17. Heterodimeric l-amino acid oxidase enzymes from Egyptian Cerastes cerastes venom: Purification, biochemical characterization and partial amino acid sequencing

    OpenAIRE

    A.E. El Hakim; W.H. Salama; M.B. Hamed; Ali, A. A.; N.M. Ibrahim

    2015-01-01

    Two l-amino acid oxidase enzyme isoforms, Cc-LAAOI and Cc-LAAOII were purified to apparent homogeneity from Cerastes cerastes venom in a sequential two-step chromatographic protocol including; gel filtration and anion exchange chromatography. The native molecular weights of the isoforms were 115 kDa as determined by gel filtration on calibrated Sephacryl S-200 column, while the monomeric molecular weights of the enzymes were, 60, 56 kDa and 60, 53 kDa for LAAOI and LAAOII, respectively. The t...

  18. Polarographic investigations on the cadmium(II)-imidazole-amino acid systems (amino acid L-leucine or DL-serine)

    International Nuclear Information System (INIS)

    The stability constants of ternary complexes of cadmium(II) with imidazole (IM) as primary ligand and amino acids L-leucine (LE) or DL-serine (SE) as secondary ligand have been determined polarographically at 35 degC and μ=0.5M (KNO3). In each system, four mixed complexes, viz, Cd(IM)-(AA)+, Cd(IM)2-(AA)+, Cd(IM)(AA)2 and Cd(IM)2(AA)2, were formed. The relative stability of the ternary as compared to that of corresponding binary complexes has been expressed in terms of Δlog K and log X values. (author). 12 refs., 4 figs., 1 tab

  19. Pharmacological characterization of human excitatory amino acid transporters EAAT1, EAAT2 and EAAT3 in a fluorescence-based membrane potential assay

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Bräuner-Osborne, Hans

    2004-01-01

    We have expressed the human excitatory amino acid transporters EAAT1, EAAT2 and EAAT3 stably in HEK293 cells and characterized the transporters pharmacologically in a conventional [(3) H]-d-aspartate uptake assay and in a fluorescence-based membrane potential assay, the FLIPR Membrane Potential (...

  20. Radiation damage of proteins in the solid state: changes of amino acid composition in catalase

    International Nuclear Information System (INIS)

    Catalase has been irradiated with 100 keV electrons under conditions simulating the hazards of electron microscopic imaging. Amino acid analysis reveals a definite pattern of amino acid destruction which is well correlated with the particular chemical structures of amino acid side chains. This pattern appears to be distinctly different from the sensitivity pattern for monoamino acid systems which is ascribed to intramolecular energy transfer and selective attack of liberated radicals

  1. Identification of a Vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants

    OpenAIRE

    So-ichiro Nishiyama; Yohei Takahashi; Kentaro Yamamoto; Daisuke Suzuki; Yasuaki Itoh; Kazumasa Sumita; Yumiko Uchida; Michio Homma; Katsumi Imada; Ikuro Kawagishi

    2016-01-01

    Vibrio cholerae, the etiological agent of cholera, was found to be attracted by taurine (2-aminoethanesulfonic acid), a major constituent of human bile. Mlp37, the closest homolog of the previously identified amino acid chemoreceptor Mlp24, was found to mediate taxis to taurine as well as L-serine, L-alanine, L-arginine, and other amino acids. Methylation of Mlp37 was enhanced upon the addition of taurine and amino acids. Isothermal titration calorimetry demonstrated that a purified periplasm...

  2. Compositional changes of proteins and amino acids in germinating coffee seeds

    OpenAIRE

    Milton Massao Shimizu; Paulo Mazzafera

    2000-01-01

    Endosperm is the main reserve tissue in coffee seeds. Coffee (Coffea arabica L.) seeds were germinated for six weeks and qualitative and quantitative changes in amino acids and proteins were investigated. The total content of free amino acids were reduced during germination, however, protein content remained constant. SDS-PAGE profiles showed that legumin-like proteins became less stained in the last weeks. Asparagine, glutamic acid, aspartic acid, alanine and lysine were the major free amino...

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

    Energy Technology Data Exchange (ETDEWEB)

    Chia, Mathias Ahii, E-mail: chia28us@yahoo.com [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Lombardi, Ana Teresa [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Graça Gama Melão, Maria da [Department of Hydrobiology, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Parrish, Christopher C. [Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, Newfoundland A1C 5S7 (Canada)

    2015-03-15

    Highlights: • Chlorella vulgaris was exposed to Cd under varying N concentrations. • Growth rate and cell density decreased with increasing Cd stress and N limitation. • Dry weight, chlorophyll a, total lipid, carbohydrate and protein were accumulated. • Amino acids like proline and glutamine were accumulated under N and Cd stress. • Changes in amino acid composition are sensitive biomarkers for Cd and N stress. - Abstract: 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{sup −7} and 2.0 × 10{sup −8} mol L{sup −1} Cd) under varying nitrogen (2.9 × 10{sup −6}, 1.1 × 10{sup −5} and 1.1 × 10{sup −3} mol L{sup −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.

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

    International Nuclear Information System (INIS)

    Highlights: • Chlorella vulgaris was exposed to Cd under varying N concentrations. • Growth rate and cell density decreased with increasing Cd stress and N limitation. • Dry weight, chlorophyll a, total lipid, carbohydrate and protein were accumulated. • Amino acids like proline and glutamine were accumulated under N and Cd stress. • Changes in amino acid composition are sensitive biomarkers for Cd and N stress. - Abstract: 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 mol L−1 Cd) under varying nitrogen (2.9 × 10−6, 1.1 × 10−5 and 1.1 × 10−3 mol L−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

  5. Organic acid effect on calcium uptake by the wheat roots

    Directory of Open Access Journals (Sweden)

    Fabrize Caroline Nunes

    2009-02-01

    Full Text Available This work evaluated the effect of the natural organic acids on the uptake of Ca by the wheat roots in a hydroponic solution. The following organic acids were evaluated: citric, oxalic, tartaric, malic, malonic, maleic, DL-malic, p-hydroxybenzoic, aconitic, and salicilic. The organic acids neither enhanced the root growth nor increased Ca uptake. The salicilic and malic acids were highly toxic and decreased the root growth. The citric, tartaric, maleic, aconitic, and salicilic decreased the Ca uptake by the roots due to their higher capacity to form the stable complexes with Ca in solution at pH 6.0. Decreasing the Ca valence from Ca++ to CaL+ or CaL2(0 through the organic ligand complexation reactions decreased the Ca uptake. The results suggested that the wheat roots do not absorb Ca-organic complexes.Ácidos orgânicos possuem grupos funcionais com cargas negativas que complexam íons metálicos em solução. Este trabalho avaliou o efeito de ácidos orgânicos naturais na absorção de Ca pelas raízes de trigo. Foram avaliados os seguintes ácidos orgânicos: cítrico, oxálico, tartarico, málico, malônico, maleico, DL-málico, p-hidroxibenzoico, aconítico e salicílico. Os ácidos orgânicos não estimularam o crescimento das raízes e não aumentaram a absorção de Ca. Os ácidos salicílico e maleico diminuíram drasticamente o crescimento radicular. Os ácidos cítrico, tartárico, maleico, aconítico e salicílico diminuíram a absorção de Ca pelas raízes devido à maior capacidade de formar complexos estáveis com Ca em solução no pH 6,0. A redução da valência de Ca++ para CaL+ e CaL2(0, através das reações de complexação, diminuiu a absorção de Ca pelas raízes. Os resultados sugerem que os complexos de Ca-orgânico não são absorvidos pelas raízes de trigo.

  6. Amino Acid Transport Associated to Cluster of Differentiation 98 Heavy Chain (CD98hc) Is at the Cross-road of Oxidative Stress and Amino Acid Availability.

    Science.gov (United States)

    de la Ballina, Laura R; Cano-Crespo, Sara; González-Muñoz, Elena; Bial, Susanna; Estrach, Soline; Cailleteau, Laurence; Tissot, Floriane; Daniel, Hannelore; Zorzano, Antonio; Ginsberg, Mark H; Palacín, Manuel; Féral, Chloé C

    2016-04-29

    CD98hc functions as an amino acid (AA) transporter (together with another subunit) and integrin signaling enhancer. It is overexpressed in highly proliferative cells in both physiological and pathological conditions. CD98hc deletion induces strong impairment of cell proliferation in vivo and in vitro Here, we investigate CD98hc-associated AA transport in cell survival and proliferation. By using chimeric versions of CD98hc, the two functions of the protein can be uncoupled. Although recovering the CD98hc AA transport capacity restores the in vivo and in vitro proliferation of CD98hc-null cells, reconstitution of the integrin signaling function of CD98hc is unable to restore in vitro proliferation of those cells. CD98hc-associated transporters (i.e. xCT, LAT1, and y(+)LAT2 in wild-type cells) are crucial to control reactive oxygen species and intracellular AA levels, thus sustaining cell survival and proliferation. Moreover, in CD98hc-null cells the deficiency of CD98hc/xCT cannot be compensated, leading to cell death by ferroptosis. Supplementation of culture media with β-mercaptoethanol rescues CD98hc-deficient cell survival. Under such conditions null cells show oxidative stress and intracellular AA imbalance and, consequently, limited proliferation. CD98hc-null cells also present reduced intracellular levels of branched-chain and aromatic amino acids (BCAAs and ARO AAs, respectively) and induced expression of peptide transporter 1 (PEPT1). Interestingly, external supply of dipeptides containing BCAAs and ARO AAs rescues cell proliferation and compensates for impaired uptake of CD98hc/LAT1 and CD98hc/y(+)LAT2. Our data establish CD98hc as a master protective gene at the cross-road of redox control and AA availability, making it a relevant therapeutic target in cancer. PMID:26945935

  7. Photochemical addition of amino acids and peptides to homopolyribonucleotides of the major DNA bases

    International Nuclear Information System (INIS)

    The photochemical quantum yields for addition of glycine and the L-amino acids commonly occurring in proteins to polyadenylic acid, polycytidylic acid, polyguanylic acid and polyribothymidylic acid have been determined in deoxygenated phosphate buffer using a fluorescamine assay technique. Polyadenylic acid was reactive with eleven of the twenty amino acids tested, with phenylalanine, tyrosine, glutamine, lysine and asparagine having the highest quantum yields. Polyguanylic acid reacted with sixteen amino acids; phenylalanine, arginine, cysteine, tyrosine, and lysine displayed the largest quantum yields. Polycytidylic acid showed reactivity with fifteen amino acids with lysine, phenylalanine, cysteine, tyrosine and arginine having the greatest quantum yields. Polyribothymidylic acid, reactive with fifteen of nineteen amino acids surveyed, showed the highest quantum yields for cysteine, phenylalanine, tyrosine, lysine and asparagine. None of the polynucleotides were reactive with aspartic acid or glutamic acid. The quantum yields for photoaddition of eighteen dipeptides of the form gycyl X (X being an amino acid), and of L-alanyl-L-tryptophan, L-seryl-L-seryl-L-serine, L-threonyl-L-threonyl-L-threonine, L-cystine-bis-glycine, and Nsup(α)-acetyllysine to polyadenylic acid, polycytidylic acid and polyguanylic acid were measured. All were found to add photochemically to each of these polymers. Polyribothymidylic acid, tested with eleven peptides and with Nsup(α)-acetyllysine, was found to be reactive with all. (author)

  8. Amino Acid Export in Plants: A Missing Link in Nitrogen Cycling

    Institute of Scientific and Technical Information of China (English)

    Sakiko Okumoto; Guillaume Pilot

    2011-01-01

    T The export of nutrients from source organs to parts of the body where they are required (e.g. sink organs) is a fundamental biological process. Export of amino acids, one of the most abundant nitrogen species in plant long-distance transport tissues (i.e. xylem and phloem), is an essential process for the proper distribution of nitrogen in the plant. Physiological studies have detected the presence of multiple amino acid export systems in plant cell membranes. Yet, surprisingly little is known about the molecular identity of amino acid exporters, partially due to the technical difficulties hampering the identification of exporter proteins. In this short review, we will summarize our current knowledge about amino acid export systems in plants. Several studies have described plant amino acid transporters capable of bi-directional, facilitative transport, reminiscent of activities identified by earlier physiological studies. Moreover, recent expansion in the number of available amino acid transporter sequences have revealed evolutionary relationships between amino acid exporters from other organisms with a number of uncharacterized plant proteins, some of which might also function as amino acid exporters. In addition, genes that may regulate export of amino acids have been discovered. Studies of these putative transporter and regulator proteins may help in understanding the elusive molecular mechanisms of amino acid export in plants.

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

    Science.gov (United States)

    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)

  10. Unsaturated amino acids derived from isoleucine trigger early membrane effects on plant cells.

    Science.gov (United States)

    Roblin, Gabriel; Laduranty, Joëlle; Bonmort, Janine; Aidene, Mohand; Chollet, Jean-François

    2016-10-01

    Unsaturated amino acids (UnsAA) have been shown to affect the activity of various biological processes. However, their mode of action has been investigated poorly thus far. We show in this work that 2-amino-3-methyl-4-pentenoic acid (C2) and 2-amino-3-methyl-4-pentynoic acid (C3) structurally derived from isoleucine (Ile) exhibited a multisite action on plant cells. For one, C2 and C3 induced early modifications at the plasma membrane level, as shown by the hyperpolarization monitored by microelectrode implantation in the pulvinar cells of Mimosa pudica, indicating that these compounds are able to modify ionic fluxes. In particular, proton (H(+)) fluxes were modified, as shown by the pH rise monitored in the bathing medium of pulvinar tissues. A component of this effect may be linked to the inhibitory effect observed on the proton pumping and the vanadate-sensitive activity of the plasma membrane H(+)-ATPase monitored in plasma membrane vesicles (PMVs) purified from pulvinar tissues of M. pudica and leaf tissues of Beta vulgaris. This effect may explain, in part, the inhibitory effect of the compounds on the uptake capacity of sucrose and valine by B. vulgaris leaf tissues. In contrast, an unexpected action was observed in cell reactions, implicating ion fluxes and water movement. Indeed, the osmocontractile reactions of pulvini induced either by a mechanical shock in M. pudica or by dark and light signals in Cassia fasciculata were increased, indicating that, compared to Ile, these compounds may modify in a specific way the plasma membrane permeability to water and ions. PMID:27254795

  11. Effect of N deposition on tree amino acid concentrations in two Sphagnum species

    Energy Technology Data Exchange (ETDEWEB)

    Karsisto, M.; Kitunen, V. [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

  12. Microbial production of amino acids and derived chemicals: synthetic biology approaches to strain development.

    Science.gov (United States)

    Wendisch, Volker F

    2014-12-01

    Amino acids are produced at the multi-million-ton-scale with fermentative production of l-glutamate and l-lysine alone being estimated to amount to more than five million tons in the year 2013. Metabolic engineering constantly improves productivities of amino acid producing strains, mainly Corynebacterium glutamicum and Escherichia coli strains. Classical mutagenesis and screening have been accelerated by combination with intracellular metabolite sensing. Synthetic biology approaches have allowed access to new carbon sources to realize a flexible feedstock concept. Moreover, new pathways for amino acid production as well as fermentative production of non-native compounds derived from amino acids or their metabolic precursors were developed. These include dipeptides, α,ω-diamines, α,ω-diacids, keto acids, acetylated amino acids and ω-amino acids. PMID:24922334

  13. Inhibition of beta-amino acid transport by diamide does not involve the brush border membrane surface

    International Nuclear Information System (INIS)

    Diamide (dicarboxylic acid bis-(N,N-dimethylamide) has been shown in previous studies to block the uptake of the beta-amino acid taurine at its high affinity transport site in rat renal cortex slices. Diamide may act by increasing the efflux of taurine from the slice. Studies performed in rat slices again indicate enhanced efflux over 8-12 minutes. The time course of reduced glutathione (GSH) depletion from renal cortex is similar, indicating a potential interaction between GSH depletion and inhibition of taurine accumulation. The effect of 9 mM diamide on the Na+ -dependent accumulation of taurine (10 and 250 microM) by brush border membrane vesicles was examined, and the taurine uptake value both initially and at equilibrium was the same in the presence and absence of diamide. Isolation of the brush border surface and subsequent transport studies of taurine are not influenced by diamide. Thus, diamide inhibition of taurine uptake does not involve physiochemical alteration of the membrane surface where active amino acid transport occurs, despite the thiol-oxidizing properties of this agent. Further, these studies suggest that diamide either acts at the basolateral surface, rather than the brush border surface of rat renal cortex or requires the presence of an intact tubule, capable of metabolism, prior to its inhibitory action

  14. Catabolism of Branched Chain Amino Acids Supports Respiration but Not Volatile Synthesis in Tomato Fruits

    Institute of Scientific and Technical Information of China (English)

    Andrej Kochevenko; Wagner L.Araújo; Gregory S.Maloney; Denise M.Tieman; Phuc Thi Do; Mark G.Taylor; Harry J.Klee; Alisdair R.Fernie

    2012-01-01

    The branched-chain amino acid transaminases (BCATs) have a crucial role in metabolism of the branched-chain amino acids leucine,isoleucine,and valine.These enzymes catalyze the last step of synthesis and the initial step of degradation of these amino acids.Although the biosynthetic pathways of branched chain amino acids in plants have been extensively investigated and a number of genes have been characterized,their catabolism in plants is not yet completely understood.We previously characterized the branched chain amino acid transaminase gene family in tomato,revealing both the subcellular localization and kinetic properties of the enzymes encoded by six genes.Here,we examined possible functions of the enzymes during fruit development.We further characterized transgenic plants differing in the expression of branched chain amino acid transaminases 1 and 3,evaluating the rates of respiration in fruits deficient in BCAT1 and the levels of volatiles in lines overexpressing either BCAT1 or BCAT3.We quantitatively tested,via precursor and isotope feeding experiments,the importance of the branched chain amino acids and their corresponding keto acids in the formation of fruit volatiles.Our results not only demonstrate for the first time the importance of branched chain amino acids in fruit respiration,but also reveal that keto acids,rather than amino acids,are the likely precursors for the branched chain flavor volatiles.

  15. A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites

    Science.gov (United States)

    Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.

    2012-01-01

    Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.

  16. Evidence from Meteorites for Multiple Possible Amino Acid Alphabets for the Origins of Life

    Science.gov (United States)

    Burton, A. S.; Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.

    2015-01-01

    A key question for the origins of life is understanding which amino acids made up the first proteins synthesized during the origins of life. The canonical set of 20 - 22 amino acids used in proteins are all alpha-amino, alpha-hydrogen isomers that, nevertheless, show considerable variability in properties including size, hydrophobicity, and ionizability. Abiotic amino acid synthesis experiments such as Miller-Urey spark discharge reactions produce a set of up to 23 amino acids, depending on starting materials and reaction conditions, with significant abundances of both alpha- and non-alpha-amino acid isomers. These two sets of amino acids do not completely overlap; of the 23 spark discharge amino acids, only 11 are used in modern proteins. Furthermore, because our understanding of conditions on the early Earth are limited, it is unclear which set(s) of conditions employed in spark discharge or hydrothermal reactions are correct, leaving us with significant uncertainty about the amino acid alphabet available for the origins of life on Earth. Meteorites, the surviving remnants of asteroids and comets that fall to the Earth, offer the potential to study authentic samples of naturally-occurring abiotic chemistry, and thus can provide an alternative approach to constraining the amino acid library during the origins of life.

  17. Opposite Regulation of CD36 Ubiquitination by Fatty Acids and Insulin: EFFECTS ON FATTY ACID UPTAKE*

    OpenAIRE

    Smith, Jill; Su, Xiong; El-Maghrabi, Raafat; Stahl, Philip D.; Abumrad, Nada A.

    2008-01-01

    FAT/CD36 is a membrane scavenger receptor that facilitates long chain fatty acid uptake by muscle. Acute increases in membrane CD36 and fatty acid uptake have been reported in response to insulin and contraction. In this study we have explored protein ubiquitination as one potential mechanism for the regulation of CD36 level. CD36 expressed in Chinese hamster ovary (CHO) or HEK 293 cells was found to be polyubiquitinated via a process involving both lysines 48 and 63 of ubiquitin. Using CHO c...

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

    Science.gov (United States)

    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. PMID:21140278

  19. Tracing amino acid exchange during host-pathogen interaction by combined stable-isotope time-resolved Raman spectral imaging

    Science.gov (United States)

    Naemat, Abida; Elsheikha, Hany M.; Boitor, Radu A.; Notingher, Ioan

    2016-02-01

    This study investigates the temporal and spatial interchange of the aromatic amino acid phenylalanine (Phe) between human retinal pigment epithelial cell line (ARPE-19) and tachyzoites of the apicomplexan protozoan parasite Toxoplasma gondii (T. gondii). Stable isotope labelling by amino acids in cell culture (SILAC) is combined with Raman micro-spectroscopy to selectively monitor the incorporation of deuterium-labelled Phe into proteins in individual live tachyzoites. Our results show a very rapid uptake of L-Phe(D8) by the intracellular growing parasite. T. gondii tachyzoites are capable of extracting L-Phe(D8) from host cells as soon as it invades the cell. L-Phe(D8) from the host cell completely replaces the L-Phe within T. gondii tachyzoites 7-9 hours after infection. A quantitative model based on Raman spectra allowed an estimation of the exchange rate of Phe as 0.5-1.6 × 104 molecules/s. On the other hand, extracellular tachyzoites were not able to consume L-Phe(D8) after 24 hours of infection. These findings further our understanding of the amino acid trafficking between host cells and this strictly intracellular parasite. In particular, this study highlights new aspects of the metabolism of amino acid Phe operative during the interaction between T. gondii and its host cell.

  20. 37 CFR 1.822 - Symbols and format to be used for nucleotide and/or amino acid sequence data.

    Science.gov (United States)

    2010-07-01

    ... for nucleotide and/or amino acid sequence data. 1.822 Section 1.822 Patents, Trademarks, and... Amino Acid Sequences § 1.822 Symbols and format to be used for nucleotide and/or amino acid sequence data. (a) The symbols and format to be used for nucleotide and/or amino acid sequence data...

  1. Carrier-Mediated Uptake of 1-(Malonylamino)cyclopropane-1-Carboxylic Acid in Vacuoles Isolated from Catharanthus roseus Cells 1

    Science.gov (United States)

    Bouzayen, Mondher; Latché, Alain; Pech, Jean-Claude; Marigo, Gérard

    1989-01-01

    The uptake of 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC), the conjugated form of the ethylene precursor, into vacuoles isolated from Catharanthus roseus cells has been studied by silicone layer floatation filtering. The transport across the tonoplast of MACC is stimulated fourfold by 5 millimolar MgATP, has a Km of about 2 millimolar, an optimum pH around 7, and an optimum temperature at 30°C. Several effectors known to inhibit ATPase (N,N′-dicyclohexylcarbodiimide) and to collapse the transtonoplastic H+ electrochemical gradient (carbonylcyanide m-chlorophenylhydrazone, gramicidin, and benzylamine) all reduced MACC uptake. Abolishing the membrane potential with SCN− and valinomycin also greatly inhibited MACC transport. Our data demonstrate that MACC accumulates in the vacuole against a concentration gradient by means of a proton motive force generated by a tonoplastic ATPase. The involvement of a protein carrier is suggested by the strong inhibition of uptake by compounds known to block SH—, OH—, and NH2— groups. MACC uptake is antagonized competitively by malonyl-d-tryptophan, indicating that the carrier also accepts malonyl-d-amino acids. Neither the moities of these compounds taken separately [1-aminocyclopropane-1-carboxylic acid, malonate, d-tryptophan or d-phenylalanine] nor malate act as inhibitors of MACC transport. The absence of inhibition of malate uptake by MACC suggests that MACC and malate are taken up by two different carriers. We propose that the carrier identified here plays an important physiological role in withdrawing from the cytosol MACC and malonyl-d-amino acids generated under stress conditions. PMID:16667182

  2. Membrane fractionation of herring marinade for separation and recovery of fats, proteins, amino acids, salt, acetic acid and water

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Lizarazu, Juncal Martin; Razi Parjikolaei, Behnaz;

    2015-01-01

    containing sugars, amino acids and smaller peptides and a NF permeate containing salt and acetic acid ready for reuse. 42% of the spent marinade is recovered to substitute fresh water and chemicals. The Waste water amount is reduced 62.5%. Proteins are concentrated 30 times, while amino acids and smaller...

  3. Effects of CO2 enrichment on the metabolism of soluble amino acids and organic acids in barley primary leaves

    Science.gov (United States)

    Responses of soluble amino acids and organic acids to CO2 enrichment were determined with barley primary leaves (Hordeum vulgare L. cv. Brant) grown in controlled environment chambers. Total soluble amino acids were enhanced 33% by CO2 enrichment when determined 9 days after sowing (DAS). However,...

  4. Positron emission tomography (PET) study of patients with pituitary adenoma using labeled amino acid

    Energy Technology Data Exchange (ETDEWEB)

    Mineura, Katsuyoshi; Sasajima, Toshio; Sakamoto, Tetsuya; Kowada, Masayoshi (Akita Univ. (Japan). Hospital); Shishido, Fumio; Uemura, Kazuo

    1989-12-01

    Four cases with pituitary adenomas were studied using {sup 11}C-L-methionine (C-11 Met) positron-emission tomography (PET). The C-11 Met was intravenously administered at a dose of 0.6 mCi/kg. The uptake of the tracer for tumors was calculated on the PET images 45 min after the injection; the uptake index was represented as a percentage of the total count in the arterial blood over a period of 45 min. In all cases, the C-11 Met accumulated intensely in the tumor regions; the PET images clearly delineated the extent of the tumor. The C-11 Met uptake index for pituitary adenomas varied widely from 3.94 x 10{sup -2}% to 15.36 x 10{sup -2}%, with a mean of 7.87 x 10{sup -2}%. These indices for the tumors increased markedly in comparison with that of the contralateral left temporal gray matter as a nontumor region (1.89 x 10{sup -2}% to 2.43 x 10{sup -2}% with a mean of 2.06 x 10{sup -2}%). In a case of prolactinoma, repeated PET following bromocriptine treatment showed a decrease in the C-11 Met uptake index; this decrease reflected changes in the serum prolactin value. In another case with ACTH-producing adenoma, the T/NT (tumor/nontumor) ratio fell from 3.44 to 2.40; however, the C-11 Met index remained unchanged. C-11 Met PET images facilitate determining the extent of pituitary adenomas and the monitoring of tumor response to treatment. Further application may give useful knowledge on the amino-acid metabolism of the tumor. (author).

  5. Physical and functional interactions between the serotonin transporter and the neutral amino acid transporter ASCT2.

    Science.gov (United States)

    Seyer, Pascal; Vandermoere, Franck; Cassier, Elisabeth; Bockaert, Joël; Marin, Philippe

    2016-07-01

    The activity of serotonergic systems depends on the reuptake of extracellular serotonin via its plasma membrane serotonin [5-HT (5-hydroxytryptamine)] transporter (SERT), a member of the Na(+)/Cl(-)-dependent solute carrier 6 family. SERT is finely regulated by multiple molecular mechanisms including its physical interaction with intracellular proteins. The majority of previously identified SERT partners that control its functional activity are soluble proteins, which bind to its intracellular domains. SERT also interacts with transmembrane proteins, but its association with other plasma membrane transporters remains to be established. Using a proteomics strategy, we show that SERT associates with ASCT2 (alanine-serine-cysteine-threonine 2), a member of the solute carrier 1 family co-expressed with SERT in serotonergic neurons and involved in the transport of small neutral amino acids across the plasma membrane. Co-expression of ASCT2 with SERT in HEK (human embryonic kidney)-293 cells affects glycosylation and cell-surface localization of SERT with a concomitant reduction in its 5-HT uptake activity. Conversely, depletion of cellular ASCT2 by RNAi enhances 5-HT uptake in both HEK-293 cells and primary cultured mesencephalon neurons. Mimicking the effect of ASCT2 down-regulation, treatment of HEK-293 cells and neurons with the ASCT2 inhibitor D-threonine also increases 5-HT uptake. Moreover, D-threonine does not enhance further the maximal velocity of 5-HT uptake in cells depleted of ASCT2. Collectively, these findings provide evidence for a complex assembly involving SERT and a member of another solute carrier family, which strongly influences the subcellular distribution of SERT and the reuptake of 5-HT. PMID:27143784

  6. Positron emission tomography (PET) study of patients with pituitary adenoma using labeled amino acid

    International Nuclear Information System (INIS)

    Four cases with pituitary adenomas were studied using 11C-L-methionine (C-11 Met) positron-emission tomography (PET). The C-11 Met was intravenously administered at a dose of 0.6 mCi/kg. The uptake of the tracer for tumors was calculated on the PET images 45 min after the injection; the uptake index was represented as a percentage of the total count in the arterial blood over a period of 45 min. In all cases, the C-11 Met accumulated intensely in the tumor regions; the PET images clearly delineated the extent of the tumor. The C-11 Met uptake index for pituitary adenomas varied widely from 3.94 x 10-2% to 15.36 x 10-2%, with a mean of 7.87 x 10-2%. These indices for the tumors increased markedly in comparison with that of the contralateral left temporal gray matter as a nontumor region (1.89 x 10-2% to 2.43 x 10-2% with a mean of 2.06 x 10-2%). In a case of prolactinoma, repeated PET following bromocriptine treatment showed a decrease in the C-11 Met uptake index; this decrease reflected changes in the serum prolactin value. In another case with ACTH-producing adenoma, the T/NT (tumor/nontumor) ratio fell from 3.44 to 2.40; however, the C-11 Met index remained unchanged. C-11 Met PET images facilitate determining the extent of pituitary adenomas and the monitoring of tumor response to treatment. Further application may give useful knowledge on the amino-acid metabolism of the tumor. (author)

  7. High-level production of C-11-carboxyl-labeled amino acids

    International Nuclear Information System (INIS)

    Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period

  8. Effect of methyl jasmonate application to grapevine leaves on grape amino acid content.

    Science.gov (United States)

    Garde-Cerdán, Teresa; Portu, Javier; López, Rosa; Santamaría, Pilar

    2016-07-15

    Over the last few years, considerable attention has been paid to the application of elicitors to vineyard. However, research about the effect of elicitors on grape amino acid content is scarce. Therefore, the aim of this study was to evaluate the influence of foliar application of methyl jasmonate on must amino acid content. Results revealed that total amino acid content was not modified by the application of methyl jasmonate. However, the individual content of certain amino acids was increased as consequence of methyl jasmonate foliar application, i.e., histidine, serine, tryptophan, phenylalanine, tyrosine, asparagine, methionine, and lysine. Among them, phenylalanine content was considerably increased; this amino acid is precursor of phenolic and aromatic compounds. In conclusion, foliar application of methyl jasmonate improved must nitrogen composition. This finding suggests that methyl jasmonate treatment might be conducive to obtain wines of higher quality since must amino acid composition could affect the wine volatile composition and the fermentation kinetics. PMID:26948648

  9. Riboflavin enhances photo-oxidation of amino acids under simulated clinical conditions

    International Nuclear Information System (INIS)

    In neonatal nurseries, solutions of amino acids with added vitamins may be exposed to relatively intense light from phototherapy units. Light, especially in the presence of photosensitizers such as certain vitamins, is capable of destroying amino acids. In the present study, the effect of riboflavin on amino acid concentrations in solutions exposed to light was studied. Solutions of crystalline amino acids with and without added riboflavin were infused into shielded collecting vessels for 24 hr under conditions simulating those occurring during phototherapy. Decreases in concentrations of some amino acids were observed with light exposure alone. Decreases in concentrations of methionine, proline, tryptophan, and tyrosine were significantly greater in the presence of riboflavin that in its absence. Riboflavin concentrations were also significantly reduced after light exposure. Although the losses of amino acids are probably not nutritionally significant, the photo-oxidation products are largely unknown and may be toxic

  10. Cortical and subcortical gamma amino acid butyric acid deficits in anxiety and stress disorders: Clinical implications

    OpenAIRE

    Goddard, Andrew W

    2016-01-01

    Anxiety and stress disorders are a major public health issue. However, their pathophysiology is still unclear. The gamma amino acid butyric acid (GABA) neurochemical system has been strongly implicated in their pathogenesis and treatment by numerous preclinical and clinical studies, the most recent of which have been highlighted and critical review in this paper. Changes in cortical GABA appear related to normal personality styles and responses to stress. While there is accumulating animal an...

  11. Combination of amino acids reduces pigmentation in B16F0 melanoma cells.

    Science.gov (United States)

    Ishikawa, Masago; Kawase, Ichiro; Ishii, Fumio

    2007-04-01

    Amino acids, the building blocks of proteins, play significant roles in numerous physiological events in mammals. As the effects of amino acids on melanogenesis have yet to be demonstrated, the present study was conducted to identify whether amino acids, in particular alanine, glycine, isoleucine and leucine, influence melanogenesis in B16F0 melanoma cells. Glycine and L-isoleucine, but not D-isoleucine, reduced melanogenesis in a concentration-dependent manner without any morphological changes in B16F0 melanoma cells. L-Alanine and L-leucine, but not D-alanine and D-leucine, also reduced melanogenesis without any morphological changes in B16F0 melanoma cells. However these amino acids did not show a concentration-dependency. Combination of L-alanine and the other amino acids, particularly 4 amino acids combination, had an additive effect on the inhibition of melanogenesis compared with single treatment of L-alanine. None of the amino acids affected the activity of tyrosinase, a key enzyme in melanogenesis. These results suggest that L-alanine, glycine, L-isoleucine and L-leucine, but not the D-form amino acids, have a hypopigmenting effect in B16F0 melanoma cells, and that these effects are not due to the inhibition of tyrosinase activity. Combination of these 4 amino acids had the additive effect on hypopigmentation that was as similar as that of kojic acid. PMID:17409501

  12. Mapping the Hydropathy of Amino Acids Based on Their Local Solvation Structure

    KAUST Repository

    Bonella, S.

    2014-06-19

    In spite of its relevant biological role, no general consensus exists on the quantitative characterization of amino acid\\'s hydropathy. In particular, many hydrophobicity scales exist, often producing quite different rankings for the amino acids. To make progress toward a systematic classification, we analyze amino acids\\' hydropathy based on the orientation of water molecules at a given distance from them as computed from molecular dynamics simulations. In contrast with what is usually done, we argue that assigning a single number is not enough to characterize the properties of an amino acid, in particular when both hydrophobic and hydrophilic regions are present in a residue. Instead we show that appropriately defined conditional probability densities can be used to map the hydrophilic and hydrophobic groups on the amino acids with greater detail than possible with other available methods. Three indicators are then defined based on the features of these probabilities to quantify the specific hydrophobicity and hydrophilicity of each amino acid. The characterization that we propose can be used to understand some of the ambiguities in the ranking of amino acids in the current scales. The quantitative indicators can also be used in combination with standard bioinformatics tools to predict the location of transmembrane regions of proteins. The method is sensitive to the specific environment of the amino acids and can be applied to unnatural and modified amino acids, as well as to other small organic molecules. © 2014 American Chemical Society.

  13. Computational Modeling of the Optical Rotation of Amino Acids: An "in Silico" Experiment for Physical Chemistry

    Science.gov (United States)

    Simpson, Scott; Autschbach, Jochen; Zurek, Eva

    2013-01-01

    A computational experiment that investigates the optical activity of the amino acid valine has been developed for an upper-level undergraduate physical chemistry laboratory course. Hybrid density functional theory calculations were carried out for valine to confirm the rule that adding a strong acid to a solution of an amino acid in the l…

  14. Amino acids as corrosion inhibitors for copper in acidic medium: Experimental and theoretical study

    Directory of Open Access Journals (Sweden)

    Milošev Ingrid

    2013-01-01

    Full Text Available Experimental electrochemical methods combined with quantum chemical calculations and molecular dynamics simulations were used to investigate the possibility of use various amino acids as “green” corrosion inhibitors for copper in 0.5 M HCl solution. Among eleven amino acids studied, cysteine achieved the highest inhibitor effectiveness reaching 52% at 10 mM concentration. Other amino acids reached achieved effectiveness less than 25%, some of them even acted as corrosion accelerators. Based on the experimental results, theoretical calculations and simulations were focused on cysteine and alanine. The electronic and reactivity parameters of their protonated forms in electrical double layer were evaluated by density functional calculations. In addition, molecular dynamic simulations were introduced to follow the adsorption behaviour of these two amino acids at the Cu(111 surface in the electrolyte solution. The results indicate that the orientation of both molecules is nearly parallel to the surface except of ammonium group which is directed away from the surface. Therefore, as the orientation of the cysteine and alanine molecules at the surface is similar, thiol functional group is responsible for superior inhibition efficiency of cysteine.

  15. Photoinduced conductivity in mycosporine-like amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Atul; Lee, Jeong Hun; Seo, Hyo Hyun; Kim, Hyoung-Shik; Cho, Moon Jin; Shin, Dong Sun [Antiaging Research Institute of BIO-FD and C Co. Ltd., Incheon 406-840 (Korea, Republic of); Kim, Taesung [Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Moh, Sang Hyun, E-mail: shmoh@biofdnc.com [Antiaging Research Institute of BIO-FD and C Co. Ltd., Incheon 406-840 (Korea, Republic of)

    2015-02-01

    Mycosporine-like amino acids (MAAs) are an important group of novel bioactive compounds having immense biotechnological potentials due to their UV screening properties and antioxidant activities. However, their photoelectric properties were not evaluated yet. In the present work two types of MAAs Shinorine and Porphyra-334, were extracted from algae; Chlamydomonas hedlyei and Porphyra yezoensis respectively and its electrical transport properties were investigated upon illumination of UV light. The combination of optical absorption and electron transport measurement of MAAs in a field effect transistor device reveals that these changes are mainly due to the carboxyl group present in MAAs. This study reports a platform technology for the development of novel biochemical–electrical devices. - Highlights: • MAAs FET shows photoelectric effect upon UV illumination. • Enhancement in photo conductance is due to the hydroxyl ethyl group. • Potential as bio-opto-electrical devices applications.

  16. Heat-Bath Cooling of Spins in Amino Acids

    CERN Document Server

    Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2011-01-01

    Heat-bath cooling is a component of practicable algorithmic cooling of spins, an approach which might be useful for in vivo 13C spectroscopy, in particular for prolonged metabolic processes where substrates that are hyperpolarized ex-vivo are not effective. We applied heat-bath cooling to 1,2-13C2-amino acids, using the \\alpha\\ protons to shift entropy from selected carbons to the environment. For glutamate and glycine, the polarizations of both labeled carbons were enhanced, and in other experiments the total entropy of each spin system was shown to decrease. The effect of adding Magnevist, a gadolinium contrast agent, on heat-bath cooling of glutamate was investigated.

  17. Radiation chemistry of amino acids and peptides in aqueous solutions

    International Nuclear Information System (INIS)

    Radiation chemistry relevant to radiation preservation of high protein foods is reviewed. Some conclusions concerning the chemistry of irradiated amino acids, peptides, and proteins have been derived from product analysis of γ-irradiated solutions while the main mechanistic considerations result from the chemistry and kinetics of free radical intermediates observed by pulse radiolysis. The precursors of chemistry in not too concentrated solutions (-, OH, and H. Their reactivity with molecules and their preference for characteristic groups within the molecule are discussed. The reviewed reactions of the model systems are accountable for a variety of radiolytic products found in irradiated foods. From detailed understanding of radiation chemistry in aqueous and frozen systems formation of many classes of compounds can be predicted or entirely eliminated in order to corroborate and extend the conclusions reached from the animal feeding experiments concerning the formation of toxic, mutagenic, and carcinogenic compounds and/or reduction of the nutritional value of foods

  18. Excellent amino acid racemization results from Holocene sand dollars

    Science.gov (United States)

    Kosnik, M.; Kaufman, D. S.; Kowalewski, M.; Whitacre, K.

    2015-12-01

    Amino acid racemization (AAR) is widely used as a cost-effective method to date molluscs in time-averaging and taphonomic studies, but it has not been attempted for echinoderms despite their paleobiological importance. Here we demonstrate the feasibility of AAR geochronology in Holocene aged Peronella peronii (Echinodermata: Echinoidea) collected from Sydney Harbour (Australia). Using standard HPLC methods we determined the extent of AAR in 74 Peronella tests and performed replicate analyses on 18 tests. We sampled multiple areas of two individuals and identified the outer edge as a good sampling location. Multiple replicate analyses from the outer edge of 18 tests spanning the observed range of D/Ls yielded median coefficients of variation HPLC injections sampled from 74 individuals are also very high (pearson r2 > 0.95) for these four amino acids. The ages of 11 individuals spanning the observed range of D/L values were determined using 14C analyses, and Bayesian model averaging was used to determine the best AAR age model. The averaged age model was mainly composed of time-dependent reaction kinetics models (TDK, 71%) based on phenylalanine (Phe, 94%). Modelled ages ranged from 14 to 5539 yrs, and the median 95% confidence interval for the 74 analysed individuals is ±28% of the modelled age. In comparison, the median 95% confidence interval for the 11 calibrated 14C ages was ±9% of the median age estimate. Overall Peronella yields exceptionally high-quality AAR D/L values and appears to be an excellent substrate for AAR geochronology. This work opens the way for time-averaging and taphonomic studies of echinoderms similar to those in molluscs.

  19. Correlated mutations: a hallmark of phenotypic amino acid substitutions.

    Directory of Open Access Journals (Sweden)

    Andreas Kowarsch

    Full Text Available Point mutations resulting in the substitution of a single amino acid can cause severe functional consequences, but can also be completely harmless. Understanding what determines the phenotypical impact is important both for planning targeted mutation experiments in the laboratory and for analyzing naturally occurring mutations found in patients. Common wisdom suggests using the extent of evolutionary conservation of a residue or a sequence motif as an indicator of its functional importance and thus vulnerability in case of mutation. In this work, we put forward the hypothesis that in addition to conservation, co-evolution of residues in a protein influences the likelihood of a residue to be functionally important and thus associated with disease. While the basic idea of a relation between co-evolution and functional sites has been explored before, we have conducted the first systematic and comprehensive analysis of point mutations causing disease in humans with respect to correlated mutations. We included 14,211 distinct positions with known disease-causing point mutations in 1,153 human proteins in our analysis. Our data show that (1 correlated positions are significantly more likely to be disease-associated than expected by chance, and that (2 this signal cannot be explained by conservation patterns of individual sequence positions. Although correlated residues have primarily been used to predict contact sites, our data are in agreement with previous observations that (3 many such correlations do not relate to physical contacts between amino acid residues. Access to our analysis results are provided at http://webclu.bio.wzw.tum.de/~pagel/supplements/correlated-positions/.

  20. Correlated mutations: a hallmark of phenotypic amino acid substitutions.

    Science.gov (United States)

    Kowarsch, Andreas; Fuchs, Angelika; Frishman, Dmitrij; Pagel, Philipp

    2010-01-01

    Point mutations resulting in the substitution of a single amino acid can cause severe functional consequences, but can also be completely harmless. Understanding what determines the phenotypical impact is important both for planning targeted mutation experiments in the laboratory and for analyzing naturally occurring mutations found in patients. Common wisdom suggests using the extent of evolutionary conservation of a residue or a sequence motif as an indicator of its functional importance and thus vulnerability in case of mutation. In this work, we put forward the hypothesis that in addition to conservation, co-evolution of residues in a protein influences the likelihood of a residue to be functionally important and thus associated with disease. While the basic idea of a relation between co-evolution and functional sites has been explored before, we have conducted the first systematic and comprehensive analysis of point mutations causing disease in humans with respect to correlated mutations. We included 14,211 distinct positions with known disease-causing point mutations in 1,153 human proteins in our analysis. Our data show that (1) correlated positions are significantly more likely to be disease-associated than expected by chance, and that (2) this signal cannot be explained by conservation patterns of individual sequence positions. Although correlated residues have primarily been used to predict contact sites, our data are in agreement with previous observations that (3) many such correlations do not relate to physical contacts between amino acid residues. Access to our analysis results are provided at http://webclu.bio.wzw.tum.de/~pagel/supplements/correlated-positions/. PMID:20862353