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Journal articles on the topic 'Labelled Metabolites'

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Published: 6 September 2023

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1

Matei, Lidia, Cristian Postolache, and Corneliu Podina. "Preparation of3H-labelled testosterone metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 50, no. 5-6 (2007): 442–43. http://dx.doi.org/10.1002/jlcr.1184.

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2

Dhuguru, Jyothi, and Marie E. Migaud. "1-(4-Aminobutyl)guanidine." Molbank 2022, no. 4 (October 9, 2022): M1463. http://dx.doi.org/10.3390/m1463.

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Isotope labelling of otherwise endogenous metabolites has emerged as a powerful approach to study metabolism-related biological processes, when used in conjunction with nuclear magnetic resonance or chromatography-supported mass spectrometry. Given the advantages of metabolite tracing in uncovering metabolic pathways, there is always a need to develop new methods to generate isotopically labelled compounds. In this direction, we developed a new synthetic route to access the labelled agmatine. To access labelled agmatine, we developed a two-step method that includes the treatment of labelled cyanamide with N-Boc-1,4-butanediamine, followed by a BOC deprotection. Structural confirmation was achieved by 1DNMR, 2DNMR and IR spectroscopy. This isotopologue of agmatine can be very helpful to study the pharmacokinetics and bio-distribution of this neurotransmitter and its metabolites in vitro and in vivo or used as an internal standard in mass spectrometry measurements.

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3

Vollmer, K. O., W. Klemisch, and A. von Hodenberg. "High Performance Liquid Chromatography Coupled with Radioactivity Detection: A Powerful Tool for Determining Drug Metabolite Profiles in Biological Fluids." Zeitschrift für Naturforschung C 41, no. 1-2 (February 1, 1986): 115–25. http://dx.doi.org/10.1515/znc-1986-1-218.

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Abstract High performance liquid chromatography coupled with continuous radioactivity detection represents an advancement in drug metabolism research. Using radioactive substances labelled in biologically stable positions, all metabolites can be specifically detected by radioactivity measurement. Thus no clean-up of biological fluids is required prior to HPLC. This can prevent artefact formation from unstable metabolites, reduces recovery problems and facilitates quantitation. Separation of highly polar and unpolar metabolites is possible in a single chromatographic run using gradient elution and reversed phase materials. This technique is also well-suited for preparative isolation and purification of metabolites for subsequent structure elucidation. Various metabolite profiles of drugs labelled with carbon-14 or tritium are shown. Metabolites of the following drugs are presented: norfenefrine, etozolin, thymoxamine, naloxone, and levobunolol. We review the general methodology and report our experience with this technique. In principle, this technique may be useful for all biological systems in which tracer techniques are applied.

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4

Feng, Shixia, and Mahmoud A. Elsohly. "Synthesis of [2H6]-labelled metabolites of cannabinoids." Journal of Labelled Compounds and Radiopharmaceuticals 43, no. 7 (2000): 655–62. http://dx.doi.org/10.1002/1099-1344(200006)43:7<655::aid-jlcr350>3.0.co;2-t.

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5

Shyadehi, Akbar Z., and John J. Harding. "Synthesis of tritium-labelled metabolites of ibuprofen." Journal of Labelled Compounds and Radiopharmaceuticals 42, no. 3 (March 1999): 207–13. http://dx.doi.org/10.1002/(sici)1099-1344(199903)42:3<207::aid-jlcr210>3.0.co;2-5.

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6

Heinkele, Georg, Ute Hofmann, Joachim Opitz, and Thomas E. Mürdter. "Syntheses of2H-labelled dihydropyrimidinediones and their metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 44, no. 1 (January 2001): 7–11. http://dx.doi.org/10.1002/jlcr.426.

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7

Krais, Annette, Christina Andersen, Axel Eriksson, Eskil Johnsson, Jörn Nielsen, Joakim Pagels, Anders Gudmundsson, Christian Lindh, and Aneta Wierzbicka. "Excretion of Urinary Metabolites of the Phthalate Esters DEP and DEHP in 16 Volunteers after Inhalation and Dermal Exposure." International Journal of Environmental Research and Public Health 15, no. 11 (November 9, 2018): 2514. http://dx.doi.org/10.3390/ijerph15112514.

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Phthalate esters are suspected endocrine disruptors that are found in a wide range of applications. The aim of this study was to determine the excretion of urinary metabolites in 16 individuals after inhalation and/or dermal exposure to 100–300 µg/m3 of deuterium-labelled diethyl phthalate (D4-DEP) and bis(2-ethylhexyl) phthalate (D4-DEHP). Dermal exposure in this study represents a case with clean clothing acting as a barrier. After inhalation, D4-DEP and D4-DEHP metabolites were excreted rapidly, though inter-individual variation was high. D4-DEP excretion peaked 3.3 h (T½ of 2.1 h) after combined inhalation and dermal exposure, with total excreted metabolite levels ranging from 0.055 to 2.351 nmol/nmol/m3 (nmol of urinary metabolites per phthalates air concentration in (nmol/m3)). After dermal exposure to D4-DEP, metabolite excretion peaked 4.6 h (T½ of 2.7 h) after exposure, with excreted metabolite levels in between 0.017 and 0.223 nmol/nmol/m3. After combined inhalation and dermal exposure to D4-DEHP, the excretion of all five analysed metabolites peaked after 4.7 h on average (T½ of 4.8 h), and metabolite levels ranged from 0.072 to 1.105 nmol/nmol/m3 between participants. No dermal uptake of particle phase D4-DEHP was observed. In conclusion, the average excreted levels of metabolites after combined inhalation and dermal exposure to D4-DEP was three times higher than after combined exposure to D4-DEHP; and nine times higher than after dermal exposure of D4-DEP. This study was made possible due to the use of novel approaches, i.e., the use of labelled phthalate esters to avoid the background concentration, and innovative technique of phthalate generation, both in the particle and the gas phase.

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8

Mehrsheikh, Mohammad E., Lane A. Clizbe, Harbhajan Singh, and Wr Purdum. "Syntheses of 14C-labelled monoacidic metabolites of dithiopyr." Journal of Labelled Compounds and Radiopharmaceuticals 29, no. 1 (January 1991): 9–13. http://dx.doi.org/10.1002/jlcr.2580290103.

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9

Bergin, Julie A., Ryan A. Bragg, Nick Bushby, John R. Harding, Angela Jordan, David A. Killick, and Claire L. Silcock. "Synthesis of isotopically labelled AZD3409 and its metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 50, no. 5-6 (2007): 426–27. http://dx.doi.org/10.1002/jlcr.1175.

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10

Seidel, D., P. Brehmer, Y. Schoof, U. Weinberg, and M. Nowakowski. "Synthesis of [14C]-labelled vardenafil hydrochloride and metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 46, no. 11 (2003): 1019–32. http://dx.doi.org/10.1002/jlcr.736.

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11

Rood, S. B. "Heterosis and the metabolism of [3H]gibberellin A1 in maize." Canadian Journal of Botany 64, no. 9 (September 1, 1986): 2160–64. http://dx.doi.org/10.1139/b86-285.

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Seedling growth and the metabolism of high specific activity (1.1 TBq mmol−1) [3H]gibberellin A1 were studied in two Canadian maize (Zea mays L.) inbreds, CM7 and CM49, and in their single cross F1 hybrid. As previously reported, the hybrid grew more rapidly than either parental inbred. Metabolism of the [3H]GA1 was qualitatively similar in all three genotypes and [3H]-labelled metabolites were tentatively identified through sequential, step-elution silicic acid partition chromatography followed by reversed-phase C18 high-performance liquid chromatography, relative to the retention times of authentic GAs. Although the expected 2β-hydroxylation product, [3H]GA8 was not detected, a metabolite was observed at the retention time of GA8-O(2)-glucoside. Additionally, another metabolite(s) eluted at the retention time of glucosyl conjugates of GA1, and enzymic cleavage with cellulase yielded a [3H]-labelled compound which subsequently eluted at the retention time of free GA1. While the ratio of the precursor [3H]GA1 to total [3H]GA conjugate-like metabolites was similar in the three genotypes, the hybrid contained higher levels of the [3H]GA8-glucosidelike metabolite, whereas the inbreds contained higher levels of the [3H]GA1 conjugatelike metabolite(s). Thus, there are differential rates of GA1 metabolism in a maize hybrid relative to its slower-growing inbred parents.

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12

Shen, C. F., J. A. Hawari, G. Ampleman, S. Thiboutot, and S. R. Guiot. "Origin ofp-cresol in the anaerobic degradation of trinitrotoluene." Canadian Journal of Microbiology 46, no. 2 (February 1, 2000): 119–24. http://dx.doi.org/10.1139/w99-124.

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p-Cresol was repeatedly detected as a trace metabolite in anaerobic slurry reactors treating 2,4,6-trinitrotoluene (TNT)-contaminated soils. This study shows that p-cresol was not a metabolite of the anaerobic degradation of TNT, by using a combination of analytical techniques and13C-labelled TNT. Instead, p-cresol, an intermediate in the degradation pathway of some amino acids, was shown to be inhibited by TNT and its metabolites. The range and persistence of inhibition to p-cresol microbial degradation decreased with the level of amino-substitution of the derivatives. This explains why p-cresol accumulated within the TNT-treating anaerobic bioslurry, as it could not be further biodegraded in the presence of TNT. Key words: p-cresol, bioremediation, trinitrotoluene, inhibition, metabolites.

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13

Novak, Marie, Ashok Modha, Jonathan Lee, Richard Buist, and Barry Blackburn. "Metabolism of D-[1-13C]glucose in livers of Meriones unguiculatus infected with Echinococcus multilocularis." Canadian Journal of Zoology 73, no. 1 (January 1, 1995): 58–66. http://dx.doi.org/10.1139/z95-007.

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Following administration of [1-13C]glucose, sequential 13C nuclear magnetic resonance (NMR) in situ spectra were obtained from the liver of uninfected jirds (Meriones unguiculatus) and those infected with Echinococcus multilocularis over a period of 2 h. Quantitative evaluation of the flow of labelled carbon through the liver at 80 and 120 min after glucose administration revealed that although the percentage of labelled glucose utilized by the liver was the same for both groups, glycogen synthesis differed. At both times, the livers of infected animals had incorporated a smaller percentage of the [1-13C]glucose into glycogen labelled at C1 and a larger percentage into the C6 position of glucose/glycogen. In another experiment, identical with respect to the substrate administered, NMR analysis of perchloric acid extracts revealed that the livers of infected animals had lower concentrations of labelled glucose and glycogen and higher concentrations of labelled alanine and lactate than those of uninfected controls. Concentration differences were also noted for some of the unlabelled metabolites. Echinococcus multilocularis cysts contained the same labelled metabolites as the livers but the concentration of lactate was much higher. Parasite cysts also contained labelled acetate.

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14

Derdau, Volker, Thorsten Fey, and Jens Atzrodt. "Synthesis of isotopically labelled SGLT inhibitors and their metabolites." Tetrahedron 66, no. 7 (February 2010): 1472–82. http://dx.doi.org/10.1016/j.tet.2009.12.003.

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15

Benedetti, M. S., R. Battaglia, G. Vicario, and R. Roncucci. "Urinary metabolites of 14C-labelled FCE 22101 in animals." Journal of Antimicrobial Chemotherapy 23, suppl C (January 1, 1989): 173–77. http://dx.doi.org/10.1093/jac/23.suppl_c.173.

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16

Everhart, E. Thomas, Peyton Jacob, John Mendelson, and Reese T. Jones. "The synthesis of deuterium-labelled cocaine, cocaethylene and metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 42, no. 13 (December 30, 1999): 1265–75. http://dx.doi.org/10.1002/(sici)1099-1344(19991230)42:13<1265::aid-jlcr283>3.0.co;2-y.

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17

Capito, K., S. E. Hansen, and P. Thams. "Production of [3H]choline-labelled metabolites from endogenously 3H-labelled phosphatidylcholine in mouse pancreatic islets." Journal of Molecular Endocrinology 17, no. 2 (October 1996): 101–7. http://dx.doi.org/10.1677/jme.0.0170101.

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ABSTRACT The involvement of phosphatidylcholine (PC) hydrolysis in the regulation of insulin secretion was studied in mouse pancreatic islets prelabelled with [3H]choline. Phospholipase C (PLC) and phospholipase D (PLD) activities were demonstrated and also that of an enzyme that removes both fatty acids from PC and thus catalyses the production of [3H]glycerophosphorylcholine (GroPCho). After 2 min of incubation with 20 mm glucose a 35% increase in the content of [3H]GroPCho was observed in prelabelled islets, whereas the amount of [3H]lysoPC, [3H]phosphorylcholine (PCho) and [3H]choline was unaffected. After 30 min of incubation with 20 mm glucose, 0·2 mm tolbutamide, 40 mm KC1, 10 mm succinic acid monomethyl ester (SME) or 10 mm NaF, a 25-50% increase in [3H]GroPCho was observed. In the presence of 100 μm diazoxide or 35 μm RHC 80267 the glucose activation was attenuated. PLC was stimulated slightly by tolbutamide and 100 μm isoprenaline (isoproterenol), whereas SME decreased the amount of [3H]PCho by 10%. [3H]Choline content was increased by 25-40% in the presence of 0·16 μm 12-O-tetradecanoylphorbol 13-acetate (TPA), 10 mm NaF or 100 μm carbachol. This effect of fluoride was potentiated in the presence of 20 mm glucose. It is concluded that metabolism of PC to GroPCho may be involved in the regulation of glucose-stimulated insulin secretion, and that PLD may participate in insulin secretion evoked by TPA, carbachol and fluoride.

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18

Tweeddale, Helen, Lucinda Notley-McRobb, and Thomas Ferenci. "Effect of Slow Growth on Metabolism of Escherichia coli, as Revealed by Global Metabolite Pool (“Metabolome”) Analysis." Journal of Bacteriology 180, no. 19 (October 1, 1998): 5109–16. http://dx.doi.org/10.1128/jb.180.19.5109-5116.1998.

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ABSTRACT Escherichia coli growing on glucose in minimal medium controls its metabolite pools in response to environmental conditions. The extent of pool changes was followed through two-dimensional thin-layer chromatography of all 14C-glucose labelled compounds extracted from bacteria. The patterns of metabolites and spot intensities detected by phosphorimaging were found to reproducibly differ depending on culture conditions. Clear trends were apparent in the pool sizes of several of the 70 most abundant metabolites extracted from bacteria growing in glucose-limited chemostats at different growth rates. The pools of glutamate, aspartate, trehalose, and adenosine as well as UDP-sugars and putrescine changed markedly. The data on pools observed by two-dimensional thin-layer chromatography were confirmed for amino acids by independent analysis. Other unidentified metabolites also displayed different spot intensities under various conditions, with four trend patterns depending on growth rate. As RpoS controls a number of metabolic genes in response to nutrient limitation, anrpoS mutant was also analyzed for metabolite pools. The mutant had altered metabolite profiles, but only some of the changes at slow growth rates were ascribable to the known control of metabolic genes by RpoS. These results indicate that total metabolite pool (“metabolome”) analysis offers a means of revealing novel aspects of cellular metabolism and global regulation.

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19

Manuel y Keenoy, B., D. Zähner, and W. J. Malaisse. "Dissociated effects of 2-deoxy-d-glucose on d-[2-3H]glucose and d-[5-3H]glucose conversion into 3HOH in rat erythrocytes." Biochemical Journal 288, no. 2 (December 1, 1992): 433–38. http://dx.doi.org/10.1042/bj2880433.

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When rat erythrocytes were preincubated with 2-deoxy-D-glucose, the generation of both 3H-labelled acidic metabolites and 3HOH from D-[5-3H]glucose, the total production of L-lactate, and the generation of 14CO2, 14C-labelled acidic metabolites and 14C-labelled lactate from D-[1-14C]glucose or D-[U-14C]glucose were all lower than in erythrocytes preincubated in the absence of a hexose or in the presence of 3-O-methyl-D-glucose. However, preincubation with 2-deoxy-D-glucose failed to decrease the generation of 3H-labelled acidic metabolites and L-[3-3H]lactate from D-[2-3H]glucose, while decreasing the production of 3HOH more severely from D-[2-3H]glucose than from D-[5-3H]glucose. This may be attributable not solely to inhibition of D-glucose phosphorylation by 2-deoxy-D-glucose and 2-deoxy-D-glucose 6-phosphate, but also to inhibition by 2-deoxy-D-glucose 6-phosphate of hexose 6-phosphate interconversion in the reaction catalysed by phosphoglucoisomerase, as also observed with the purified enzyme. The generation of 3HOH from D-[2-3H]glucose should therefore be considered as a tool to assess the efficiency of interconversion of hexose 6-phosphates in the reaction catalysed by phosphoglucoisomerase, rather than to estimate D-glucose phosphorylation rate.

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20

TILNEY-BASSETT, AMANDA L., C. AYLISH WOOD, DOREEN A. CANTRELL, and GEORGE K. RADDA. "Fluctuations in 3H-choline-labelled metabolites in T-cell activation." Biochemical Society Transactions 21, no. 4 (November 1, 1993): 350S. http://dx.doi.org/10.1042/bst021350s.

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21

Eyanagi, R., A. Toda, Y. Ishii, H. Saito, S. Soeda, H. Shimeno, and H. Shigematsu. "Antigenicity of sulfanilamide and its metabolites using fluorescent-labelled compounds." Xenobiotica 35, no. 9 (September 2005): 911–25. http://dx.doi.org/10.1080/00498250500251533.

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22

Kasal, Alexander, Květa Fuksová, and Vladimír Pouzar. "Preparation of Unlabelled and [3H]-Labelled Epitestosterone and Its Metabolites." Collection of Czechoslovak Chemical Communications 58, no. 3 (1993): 600–611. http://dx.doi.org/10.1135/cccc19930600.

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Cold as well as [3H]-labelled substrates and metabolites IX - XI, XV, XVI, XX - XXII, XXIV, XXV and XXVIII were prepared by catalytic hydrogenation of epitestosterone (VIII) and ∆1-dehydroepitestosterone (XIII). The key step in the preparation of compound XXVIII was reaction of 3β-tosylates XXVI and XXX with potassium nitrite in dimethyl sulfoxide.

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23

Heinkele, Georg, and Thomas E. Mürdter. "Synthesis of [2H3]-labelled sulfamethoxazole and its main urinary metabolites." Journal of Labelled Compounds and Radiopharmaceuticals 50, no. 7 (2007): 656–59. http://dx.doi.org/10.1002/jlcr.1375.

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24

Heimark, L. D., S. Toon, L. K. Low, D. C. Swinney, and W. F. Trager. "The synthesis of deuterium labelled metabolites of warfarin and phenprocoumon." Journal of Labelled Compounds and Radiopharmaceuticals 23, no. 2 (February 1986): 137–48. http://dx.doi.org/10.1002/jlcr.2580230204.

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25

Geboes, Karen P., Gert De Hertogh, Vicky De Preter, Anja Luypaerts, Bert Bammens, Pieter Evenepoel, Yvo Ghoos, Karel Geboes, Paul Rutgeerts, and Kristin Verbeke. "The influence of inulin on the absorption of nitrogen and the production of metabolites of protein fermentation in the colon." British Journal of Nutrition 96, no. 6 (December 2006): 1078–86. http://dx.doi.org/10.1017/bjn20061936.

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In the present study, the production and fate of bacterial metabolites in the colon were investigated in a direct way using two substrates labelled with stable isotopes: lactose [15N, 15N]ureide as a source of labelled ammonia and egg proteins intrinsically labelled with [2H4]tyrosine as a precursor of [2H4]p-cresol. Both ammonia and phenolic compounds are believed to be carcinogenic. Stimulation of carbohydrate fermentation in order to prevent accumulation of these toxic metabolites was induced by inclusion of inulin in a test meal or by addition of inulin to the daily diet, allowing us to distinguish between changes induced by the actual presence of a fermentable carbohydrate and effects caused by a long-term dietary intervention. When a single dose of inulin was administered together with the labelled substrates, a significant increase in faecal 15N excretion, accompanied by a proportional decrease in urinary 15N excretion was observed, probably reflecting an enhanced uptake of ammonia for bacterial biosynthesis, since an increased concentration of labelled N in bacterial pellets was found. A statistically significant reduction of urinary [2H4]p-cresol excretion was also noted. Upon supplementation of inulin to the daily diet during 4 weeks, however, only a tendency towards decreased urinary excretion of both labelled and unlabelled p-cresol was noted. Further studies are warranted to confirm these results in a larger cohort.

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26

van Hall, Gerrit. "Correction factors for 13C-labelled substrate oxidation at whole-body and muscle level." Proceedings of the Nutrition Society 58, no. 4 (November 1999): 979–86. http://dx.doi.org/10.1017/s0029665199001299.

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The oxidation of fatty acids, carbohydrates and amino acids can be measured by quantifying the rate of excretion of labelled CO2 following administration of 14C- or 13C-labelled substrates at whole-body and tissue level. However, there is a theoretical need to correct the oxidation rates for the proportion of labelled CO2 that is produced via oxidation but not excreted. Furthermore, depending on the substrate and position of the C label(s), there may also be a need to correct for labelled C from the metabolized substrate that does not appear as CO2, but rather becomes temporarily fixed in other metabolites. The bicarbonate correction factor is used to correct for the labelled CO2 not excreted. Recently, an acetate correction factor has been proposed for the simultaneous correction of CO2 not excreted and label fixed in other metabolites via isotopic exchange reactions, mainly in the tricarboxylic acid cycle. Changes in metabolic rate induced, for example, by feeding, hormonal changes and physical activity, as well as infusion time, have been shown to affect both correction factors. The present paper explains the theoretical and physiological basis of these correction factors and makes recommendations as to how these correction factors should be used in various physiological conditions.

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27

Thamm, Irene, Johannes Richers, Michael Rychlik, and Konrad Tiefenbacher. "A six-step total synthesis of α-thujone and d6-α-thujone, enabling facile access to isotopically labelled metabolites." Chemical Communications 52, no. 78 (2016): 11701–3. http://dx.doi.org/10.1039/c6cc05376a.

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28

Lapadatescu, Carmen, Christian Giniès, Jean-Luc Le Quéré, and Pascal Bonnarme. "Novel Scheme for Biosynthesis of Aryl Metabolites from l-Phenylalanine in the FungusBjerkandera adusta." Applied and Environmental Microbiology 66, no. 4 (April 1, 2000): 1517–22. http://dx.doi.org/10.1128/aem.66.4.1517-1522.2000.

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ABSTRACT Aryl metabolite biosynthesis was studied in the white rot fungusBjerkandera adusta cultivated in a liquid medium supplemented with l-phenylalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors (14C- and 13C-labelledl-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic compounds (alcohols, aldehydes, and acids) were also found in fungal cultures. Intracellular enzymatic activities (phenylalanine ammonia lyase, aryl-alcohol oxidase, aryl-alcohol dehydrogenase, aryl-aldehyde dehydrogenase, lignin peroxidase) and extracellular enzymatic activities (aryl-alcohol oxidase, lignin peroxidase), as well as aromatic compounds, were detected in B. adusta cultures. Metabolite formation required de novo protein biosynthesis. Our results show that l-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanine ammonia lyase and trans-cinnamic acid was in turn converted to aromatic acids (phenylpyruvic, phenylacetic, mandelic, and benzoylformic acids); benzaldehyde was a metabolic intermediate. These acids were transformed into benzaldehyde, benzyl alcohol, and benzoic acid. Our findings support the hypothesis that all of these compounds are intermediates in the biosynthetic pathway froml-phenylalanine to aryl metabolites. Additionally,trans-cinnamic acid can also be transformed via β-oxidation to benzoic acid. This was confirmed by the presence of acetophenone as a β-oxidation degradation intermediate. To our knowledge, this is the first time that a β-oxidation sequence leading to benzoic acid synthesis has been found in a white rot fungus. A novel metabolic scheme for biosynthesis of aryl metabolites froml-phenylalanine is proposed.

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29

Matthews, Jennifer L., Clinton A. Oakley, Adrian Lutz, Katie E. Hillyer, Ute Roessner, Arthur R. Grossman, Virginia M. Weis, and Simon K. Davy. "Partner switching and metabolic flux in a model cnidarian–dinoflagellate symbiosis." Proceedings of the Royal Society B: Biological Sciences 285, no. 1892 (November 28, 2018): 20182336. http://dx.doi.org/10.1098/rspb.2018.2336.

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Metabolite exchange is fundamental to the viability of the cnidarian–Symbiodiniaceae symbiosis and survival of coral reefs. Coral holobiont tolerance to environmental change might be achieved through changes in Symbiodiniaceae species composition, but differences in the metabolites supplied by different Symbiodiniaceae species could influence holobiont fitness. Using 13 C stable-isotope labelling coupled to gas chromatography–mass spectrometry, we characterized newly fixed carbon fate in the model cnidarian Exaiptasia pallida (Aiptasia) when experimentally colonized with either native Breviolum minutum or non-native Durusdinium trenchii . Relative to anemones containing B. minutum , D. trenchii -colonized hosts exhibited a 4.5-fold reduction in 13 C-labelled glucose and reduced abundance and diversity of 13 C-labelled carbohydrates and lipogenesis precursors, indicating symbiont species-specific modifications to carbohydrate availability and lipid storage. Mapping carbon fate also revealed significant alterations to host molecular signalling pathways. In particular, D. trenchii- colonized hosts exhibited a 40-fold reduction in 13 C-labelled scyllo -inositol, a potential interpartner signalling molecule in symbiosis specificity. 13 C-labelling also highlighted differential antioxidant- and ammonium-producing pathway activities, suggesting physiological responses to different symbiont species. Such differences in symbiont metabolite contribution and host utilization may limit the proliferation of stress-driven symbioses; this contributes valuable information towards future scenarios that select in favour of less-competent symbionts in response to environmental change.

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30

Houyou, Nassima, Corinne Pau-Roblot, and Albrecht Roscher. "15N relaxation and quantification of 15N-labelled metabolites in cell extracts." Comptes Rendus Chimie 9, no. 3-4 (March 2006): 520–24. http://dx.doi.org/10.1016/j.crci.2005.06.029.

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31

Mohammad, T., K. K. Midha, and E. M. Hawes. "Synthesis of deuterium labelled analogues of S-oxidative metabolites of thioridazine." Journal of Labelled Compounds and Radiopharmaceuticals 27, no. 2 (February 1989): 181–88. http://dx.doi.org/10.1002/jlcr.2580270208.

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32

Cao, Kai, John A. Brailsford, Ming Yao, Janet Caceres-Cortes, Robert Espina, and Samuel J. Bonacorsi. "Synthesis of unlabelled and stable-isotope-labelled glucuronide metabolites of dapagliflozin and synthesis of stable-isotope-labelled dapagliflozin." Journal of Labelled Compounds and Radiopharmaceuticals 60, no. 3 (February 1, 2017): 150–59. http://dx.doi.org/10.1002/jlcr.3484.

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33

Hansel, M. C., F. J. Rowell, J. Landon, and A. M. Sidki. "Single-Reagent Polarisation Fluoroimmunoassay for Cotinine (a Nicotine Metabolite) in Urine." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 23, no. 5 (September 1986): 596–602. http://dx.doi.org/10.1177/000456328602300518.

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A rapid, single-reagent, non-separation, non-isotopic immunoassay was developed for determining levels of the nicotine metabolite, cotinine, in urine. The single reagent was prepared by pre-mixing an appropriate dilution of sheep anti-cotinine serum with a fluorescein-labelled cotinine tracer. All normal reliability criteria were satisfied. The assay was found to be specific for cotinine and there was no cross reactivity with other available nicotine metabolites and structurally-related compounds. The results obtained correlated closely with those of an established radioimmunoassay. The assay was well-suited to application in the discrimination of active smokers from non-smokers (and passive smokers).

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Nilsson-Todd, Linda K., Conny Nordin, Erik G. Jönsson, Elisabeth Skogh, and Sophie Erhardt. "Cerebrospinal fluid kynurenic acid in male patients with schizophrenia – correlation with monoamine metabolites." Acta Neuropsychiatrica 19, no. 1 (February 2007): 45–52. http://dx.doi.org/10.1111/j.1601-5215.2006.00170.x.

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Background:The tryptophan metabolite kynurenic acid (KYNA) is an endogenous glutamate/nicotinic receptor antagonist. Previous studies have shown that the concentration of the compound is increased in cerebrospinal fluid (CSF) of patients with schizophrenia. Furthermore, it has been found that the CSF concentration of KYNA is positively correlated to CSF concentrations of the monoamine metabolites homovanillic acid (HVA) and 5-hydroxy indoleacetic acid (5-HIAA) in healthy control subjects.Objectives:To study the correlations between KYNA and the monoamine metabolites HVA, 5-HIAA and 4-hydroxy-3-methoxyphenylglycol (HMPG) in CSF of male patients (n= 53, ranging from 20 to 48 years of age) with verified schizophrenia.Methods:CSF was obtained by lumbar puncture, and KYNA analysis was performed with an isocratic reversed-phase high-performance liquid chromatography system connected to a fluorescence detector. HVA, 5-HIAA and HMPG concentrations were measured by mass fragmentography with deuterium-labelled internal standards.Results:Positive intercorrelations were found between CSF KYNA, HVA and 5-HIAA, while CSF content of HMPG did not correlate to KYNA or any of the monoamine metabolites in CSF.Conclusion:The results of this study suggest that increased KYNA formation is associated with an increased dopamine and serotonin turnover in male patients with schizophrenia.

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35

Verhoeven, A. J. M., G. Gorter, M. E. Mommersteeg, and J. W. Akkerman. "The energetics of early platelet responses. Energy consumption during shape change and aggregation with special reference to protein phosphorylation and the polyphosphoinositide cycle." Biochemical Journal 228, no. 2 (June 1, 1985): 451–62. http://dx.doi.org/10.1042/bj2280451.

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Among the different platelet responses, secretion requires the greatest amount of metabolic energy. The velocities of dense, alpha- and acid hydrolase granule secretion vary in parallel with the increase in energy consumption seen in thrombin-stimulated cells. This covariance is preceded by a phase in which energy consumption is increased without the extracellular appearance of secretion markers. By treating the platelets with thrombin and hirudin we have stimulated the platelets for short intervals and succeeded in separating shape change, single platelet disappearance and secretion to a great extent. In this report we show that the early increase in energy consumption reflects the energy requirement of aggregation but not of shape change. The cost of 100% of single platelet disappearance is 2.8 mumol of ATPeq. X (10(11) platelets)-1. Concurrent analysis of phosphorylation of Mr 20 000 and 47 000 proteins and of 32P-labelled phosphatidylinositol metabolites led to the following observations. Firstly, shape change is neither accompanied by an increase in protein phosphorylation nor by changes in the steady state levels of 32P-labelled phosphatidylinositol metabolites. Secondly, when aggregation occurs both proteins are phosphorylated, but the phosphatidylinositol metabolites do not change. Thirdly, when secretion follows, more phosphorylation of the Mr 47 000 protein occurs and initially only phosphatidic acid accumulates. At a later stage of the secretion responses, more protein phosphorylation and phosphatidic acid accumulation become evident, and are now accompanied by alterations in the steady state levels of 32P-labelled (poly)phosphoinositides. Hence, the early increase in energy consumption coincides with protein phosphorylation and, at a later stage, with alterations in (poly)phosphoinositides metabolites. This demonstrates that metabolic energy is directly involved in stimulus-response coupling in aggregating platelets.

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36

Cascante, Marta, Adrian Benito, Miriam Zanuy, Pedro Vizán, Silvia Marín, and Pedro de Atauri. "Metabolic network adaptations in cancer as targets for novel therapies." Biochemical Society Transactions 38, no. 5 (September 24, 2010): 1302–6. http://dx.doi.org/10.1042/bst0381302.

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Metabolite concentrations and fluxes are the system variables that characterize metabolism. The systematic study of metabolite profiles is known as metabolomics; however, knowledge of the complete set of metabolites may not be enough to predict distinct phenotypes. A complete understanding of metabolic processes requires detailed knowledge of enzyme-controlled intracellular fluxes. These can be estimated through quantitative measurements of metabolites at different times or by analysing the stable isotope patterns obtained after incubation with labelled substrates. We have identified distinct intracellular fluxes associated with metabolic adaptations accompanying cancer. The maintenance of an imbalance between fluxes for the oxidative and non-oxidative PPP (pentose phosphate pathway) has been shown to be critical for angiogenesis and cancer cell survival. Mouse NIH 3T3 cells transformed by different mutated K-ras oncogenes have differential routing of glucose to anaerobic glycolysis, the PPP and the Krebs cycle. These results indicate that knowledge of metabolic fingerprints associated with an altered genetic profile could be exploited in the rational design of new therapies. We conclude that the understanding of the multifactorial nature of metabolic adaptations in cancer may open new ways to develop novel multi-hit antitumoral therapies.

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37

San Blas, Oscar Galilea, Juan Manuel Marchante Gayón, and José Ignacio García Alonso. "Evaluation of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) for sulfur metabolic studies using34S-labelled yeast." Journal of Analytical Atomic Spectrometry 30, no. 8 (2015): 1764–73. http://dx.doi.org/10.1039/c4ja00383g.

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A multi-collector ICP-MS instrument was evaluated for the on-line measurement of sulfur isotope ratios during the liquid chromatographic separation of sulfur metabolites in mouse urine after the oral administration of³⁴S-labelled yeast.

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38

Luurtsema, Gert, Robert C. Schuit, Kevin Takkenkamp, Mark Lubberink, N. Harry Hendrikse, Albert D. Windhorst, Carla F. M. Molthoff, Nelleke Tolboom, Bart N. M. van Berckel, and Adriaan A. Lammertsma. "Peripheral metabolism of [18F]FDDNP and cerebral uptake of its labelled metabolites." Nuclear Medicine and Biology 35, no. 8 (November 2008): 869–74. http://dx.doi.org/10.1016/j.nucmedbio.2008.09.002.

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39

Heinkele, Georg, and Thomas E. Mürdter. "Synthesis of [2H]-labelled phase-I-metabolites using 1-[2H]-pyridinium hydrochloride." Journal of Labelled Compounds and Radiopharmaceuticals 48, no. 6 (2005): 457–61. http://dx.doi.org/10.1002/jlcr.941.

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40

Kay, R. R., G. W. Taylor, K. A. Jermyn, and D. Traynor. "Chlorine-containing compounds produced during Dictyostelium development. Detection by labelling with 36Cl." Biochemical Journal 281, no. 1 (January 1, 1992): 155–61. http://dx.doi.org/10.1042/bj2810155.

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DIF-1 [Differentiation-Inducing Factor 1; 1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl)hexan-1-one] is a novel chlorinated signal molecule that induces stalk-cell differentiation during development of Dictyostelium discoideum. Here we introduce the use of the radioisotope 36Cl to label DIF-1 and other low-Mr chlorinated compounds produced during development. H.p.l.c. and t.l.c. were used to resolve the labelled compounds. We find the following. (1) At least 14 dialysable 36Cl-labelled compounds are released into the medium by cells labelled continuously through development with Na36Cl. (2) The compounds can be classified into two major groups according to their times of accumulation in development. The early group of compounds starts accumulating at the end of aggregation, co-ordinately with DIF-1; the late group is only made at the end of development, by mature fruiting bodies. There may also be an intermediate group made during culmination. (3) The early group of compounds has been identified as comprising DIF-1 and seven of its metabolites by co-chromatography with the authentic compounds. These metabolites had previously only been recognized in suspensions of living cells incubated with exogenous DIF-1. Their detection here, from cells undergoing normal development, suggests that endogenous DIF-1 is metabolized in normal development in much the same way as is DIF-1 added to cells in suspension. (4) The intermediate and late groups of compounds are not obvious DIF-1 metabolites. They may have some role unconnected with DIF signalling. (5) A group of 36Cl-labelled late compounds remain cell-associated after washing of the fruiting bodies, and these are greatly enriched in stalk, compared with spore, cells. (6) Other slime-mould species were labelled with 36Cl. All three tested, namely D. mucoroides, D. vinaceo-fuscum and P. violaceum, also produced chloro compounds. D. mucoroides produced DIF-1 by the criterion of h.p.l.c. co-elution with authentic DIF-1. A developmentally regulated metabolism of chlorinated compounds may therefore be widespread amongst slime moulds. To our knowledge, labelling with 36Cl in vivo has not been reported before and provides a powerful general method for investigating chlorinated compounds in diverse organisms.

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41

Manning, N. J., and R. J. Pollitt. "Tracer studies of the interconversion of R- and S-methylmalonic semialdehydes in man." Biochemical Journal 231, no. 2 (October 15, 1985): 481–84. http://dx.doi.org/10.1042/bj2310481.

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Two human subjects were given separate oral doses of sodium [2H6]isobutyrate and [methyl-2H3]thymine and the labelling patterns of urinary metabolites were determined. Ingestion of deuterated isobutyrate resulted in the excretion of 2H5-labelled S-3-hydroxyisobutyric acid, formed on the direct catabolic pathway, and of S- and R-[2H4]-3-hydroxyisobutyric acids, formed by the reduction of S- and R-methylmalonic semialdehydes respectively. Only the R-enantiomer of urinary 3-hydroxyisobutyric acid was labelled by thymine. This labelling pattern indicates a flow from S- to R-methylmalonic semialdehyde, suggesting that the R-enantiomer is the substrate of methylmalonic semialdehyde dehydrogenase.

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42

MASON, RALPH P., and JEREMY K. M. SANDERS. "Estimation of intracellular metabolites by specific adduct formation with infused labelled marker molecules." Biochemical Society Transactions 15, no. 1 (February 1, 1987): 146–47. http://dx.doi.org/10.1042/bst0150146.

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43

Airaksinen, Mauno M., and Kimmo Mattila. "Urinary and Gastrointestinal Excretion of Metabolites of Labelled 5-Hydroxytryptamine and 5-Hydroxytryptophan." Acta Pharmacologica et Toxicologica 25, no. 4 (March 13, 2009): 473–82. http://dx.doi.org/10.1111/j.1600-0773.1967.tb00417.x.

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44

Shear, N. H., and S. P. Spielberg. "In vitro evaluation of a toxic metabolite of sulfadiazine." Canadian Journal of Physiology and Pharmacology 63, no. 11 (November 1, 1985): 1370–72. http://dx.doi.org/10.1139/y85-225.

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We have demonstrated the in vitro production of a potentially toxic metabolite of sulfadiazine. Human lymphocytes were incubated with sulfadiazine and a murine hepatic microsomal drug metabolizing system. Toxicity to cells was assessed by trypan blue dye exclusion. Covalent binding of labelled sulfadiazine to microsomes also was studied. Sulfadiazine toxicity to cells was dependent on microsomes and NADPH. Binding and toxicity were decreased when microsomes were boiled or cytochrome P-450 inhibited, and by the addition of N-acetylcysteine or glutathione. The data suggest the production of a toxic intermediate of oxidative metabolism of sulfadiazine which is detoxified by conjugation with glutathione. Covalent binding of such metabolites to cell macromolecules could lead to cell death and, by acting as haptens, to secondary hypersensitivity reactions.

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45

Vedelago, H. R., and V. G. Mahadevappa. "Mobilization of arachidonic acid in collagen-stimulated human platelets." Biochemical Journal 256, no. 3 (December 15, 1988): 981–87. http://dx.doi.org/10.1042/bj2560981.

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Stimulation of platelets with collagen results in the mobilization of arachidonic acid (AA) from phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI). In this study the effect of aspirin, indomethacin, BW755C and prostaglandin H2 (PGH2) on labelled AA release in response to varied concentrations of collagen was investigated. Our results indicate that aspirin (0.56 mM) and indomethacin (5.6 microM) not only inhibited the collagen-mediated formation of cyclo-oxygenase metabolites, but also caused a significant reduction in the accumulation of free labelled AA and 12-hydroxyeicosatetraenoic acid (12-HETE) (21-64%). Aspirin and indomethacin also inhibited the release of [3H]AA from PC (37-75%) and PI (33-63%). The inhibition of AA release caused by aspirin was reversed partially by PGH2 (1 microM). In contrast, a smaller/no inhibition of collagen-stimulated labelled AA and 12-HETE accumulation (0-11%) and of collagen-stimulated AA loss from PC and PI was observed in the presence of BW755C. The results obtained in the presence of aspirin, indomethacin and BW755C at lower concentrations of collagen further demonstrate that AA release from PI (45-61% inhibition at 10 micrograms of collagen), but not from PC, was affected by the inhibition of cyclo-oxygenase. The results obtained on the effect of PGH2 further support that deacylation of phospholipids occurs independently of cyclo-oxygenase metabolites, particularly at higher concentrations of collagen. These results also demonstrate that aspirin and indomethacin, but not BW755C, cause a direct inhibition of collagen-induced [3H]AA liberation from PC as well as from PI. We also conclude that the diacylglycerol lipase pathway is a minor, but important, route for AA release from PI in collagen-stimulated human platelets. The mechanisms underlying the regulation of AA release by collagen in the absence of cyclo-oxygenase metabolites are not clear.

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46

Corvini, P. F. X., R. Vinken, G. Hommes, M. Mundt, J. Hollender, R. Meesters, H. Fr Schröder, and B. Schmidt. "Microbial degradation of a single branched isomer of nonylphenol by Sphingomonas TTNP3." Water Science and Technology 50, no. 5 (September 1, 2004): 189–94. http://dx.doi.org/10.2166/wst.2004.0327.

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The endocrine disrupting chemical nonylphenol (NP) is a technical product which consists of a complex mixture of nonylphenols with different alkyl side-chain isomers. Since the bio-degradation of each NP isomer may lead to its own range of metabolites, the isolation and identification of transformation products is very difficult. In order to overcome this difficulty, the nonylphenol isomer 4(3′,5′-dimethyl-3′-heptyl)-phenol (p353NP) was synthesized, and its degradation by an axenic culture of Sphingomonas TTNP3 was investigated with [ring-U-14C]-labelled and non-labelled p353NP including a time-course study. Radioactive mass balancing resulted in different polar soluble fractions, in insoluble radioactivity associated with biomass, and volatile radioactivity in the form of the mineralization product 14CO2. In the extracellular media, the presence of nonanol corresponding to the nonyl chain of the NP isomer was confirmed and its concentration was determined during the course of fermentation. No other radioactive compounds were detected beside the parent isomer. Radioactive metabolites were only found in the intracellular fraction of S. TTNP3.

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47

Schoen, J., M. Novak, and B. J. Blackburn. "Hepatic [2-13C]acetate metabolism by jirds infected with Echinococcus multilocularis." Journal of Helminthology 73, no. 3 (March 1999): 245–50. http://dx.doi.org/10.1017/s0022149x99000384.

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Carbon-13 decoupled 1H spin echo NMR spectroscopy, with and without population inversion, was used to study carbon flow between the host, Meriones unguiculatus, and the parasite, Echinococcus multilocularis. This was accomplished by monitoring [2-13C]acetate metabolism in the liver of jirds infected with metacestodes of this parasite. Thirty minutes after injection of labelled acetate solution into the portal vein, 13C enrichment was observed in hepatic acetate, β–hydroxybutyrate, succinate, alanine, lactate and glucose. For E. multilocularis cysts, at this time,13C enrichment was observed in the same metabolites as in livers and, in addition, citrate. At 120 min there was a significant decrease in the amount of label present in all hepatic metabolites whereas more label was found in the majority of the parasite metabolites. The results confirm that exogenous acetate, through randomization of the 13C in biochemical pathways of host liver, ends up in hepatic glucose. As this biosynthetic route is not available to the parasite, the presence of 13C enriched glucose in the cysts clearly indicates that the parasite is siphoning off glucose that is newly synthesized by the host. At 120 min some of this labelled glucose was stored in parasite glycogen whereas some of it had been catabolized to succinate, alanine, lactate and acetate, end products which are excreted back into the host.

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48

Whiting, P., and L. Dinan. "Formation of apolar ecdysteroid conjugates by ovaries of the house cricket Acheta domesticus in vitro." Biochemical Journal 252, no. 1 (May 15, 1988): 95–103. http://dx.doi.org/10.1042/bj2520095.

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The newly laid eggs of the house cricket Acheta domesticus contain apolar ecdysteroid conjugates, which we have hypothesized to be ecdysone long-chain fatty acyl esters [Whiting & Dinan (1988) J. Insect Physiol., in the press]. The ovaries of mature adult female A. domesticus in vitro convert [3H]ecdysone into apolar conjugates identical with those found in newly laid eggs. Comparison of the radioactive metabolites produced on incubation of [3H]ecdysone with various organs of adult female A. domesticus in vitro indicate that the fat-body is the major producer of polar ecdysteroid metabolites at this stage of development, whereas the ovaries are the major site of production of apolar metabolites. Apolar metabolites are also produced to a lesser extent by the crop, gut sections and the fat-body. Hydrolysis of radioactive metabolites produced by the ovaries with Helix enzymes releases only [3H]ecdysone, and thus ecdysone is not metabolized before conjugation by the ovaries. Formation of chemical derivatives (acetonide and acetates) of these 3H-labelled apolar conjugates strongly indicates that the position of conjugation is through the hydroxy group at C-22 of ecdysone. Extensive chromatographic analysis of the 3H-labelled apolar metabolites produced by the ovaries by t.l.c. and h.p.l.c. and comparison with authenticated reference compounds have conclusively demonstrated that the conjugates consist of ecdysone esterified at C-22 to a mixture of common long-chain fatty acids. The major fatty acyl esters have been identified and their percentage contribution to the mixture determined: laurate (0.5%), myristate (2.8%), palmitate (25.8%), stearate (8.4%), arachidate (1.0%), oleate (15.7%), linoleate (38.8%) and linolenate (2.1%). In addition there are three minor unidentified peaks, one of which has been tentatively identified as ecdysone 22-palmitoleate (2.6%). Comparison of this percentage composition with the previously published fatty acid composition of A. domesticus haemolymph [Wang & Patton (1969) J. Insect Physiol. 15, 851-860] reveals remarkable similarities, indicating that the acyl transferase(s) forming the conjugates have a broad specificity with regard to the fatty acyl substrate.

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Serbian, Immo, Anne Loesche, Sven Sommerwerk, Phil Liebing, Dieter Ströhl, and René Csuk. "In the Mists of a Fungal Metabolite: An Unexpected Reaction of 2,4,5-Trimethoxyphenylglyoxylic Acid." Molecules 25, no. 8 (April 23, 2020): 1978. http://dx.doi.org/10.3390/molecules25081978.

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The reactions of phenylglyoxylic acids during the synthesis and biological evaluation of fungal metabolites led to the discovery of hitherto unknown compounds with a p-quinone methide (p-QM) structure. The formation of these p-QMs using 13C-labelled starting materials revealed a key-step of this reaction being a retro-Friedel–Crafts alkylation.

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50

Bonnet, Laurianne, Marielle Margier, Ljubica Svilar, Charlene Couturier, Emmanuelle Reboul, Jean-Charles Martin, Jean-François Landrier, and Catherine Defoort. "Simple Fast Quantification of Cholecalciferol, 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D in Adipose Tissue Using LC-HRMS/MS." Nutrients 11, no. 9 (August 22, 2019): 1977. http://dx.doi.org/10.3390/nu11091977.

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Vitamin D metabolism is actively modulated in adipose tissue during obesity. To better investigate this process, we develop a specific LC-HRMS/MS method that can simultaneously quantify three vitamin D metabolites, i.e., cholecalciferol, 25-hydroxyvitamin D3 (25(OH)D3), and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in a complex matrix, such as mouse adipose tissue and plasma. The method uses pretreatment with liquid–liquid or solid–phase extraction followed by derivatization using Amplifex® reagents to improve metabolite stability and ionization efficiency. Here, the method is optimized by co-eluting stable isotope-labelled internal standards to calibrate each analogue and to spike biological samples. Intra-day and inter-day relative standard deviations were 0.8–6.0% and 2.0–14.4%, respectively for the three derivatized metabolites. The limits of quantification (LoQ) achieved with Amplifex® derivatization were 0.02 ng/mL, 0.19 ng/mL, and 0.78 ng/mL for 1,25(OH)2D3, 25(OH)D3 and cholecalciferol, respectively. Now, for the first time, 1,25(OH)2D3 can be co-quantified with cholecalciferol and 25(OH)D3 in mouse adipose tissue. This validated method is successfully applied to study the impact of obesity on vitamin D status in mice.

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