Isotope Incorporation (isotope + incorporation)

Distribution by Scientific Domains


Selected Abstracts


Access to Any Site-Directed Isotopomer of Methionine, Selenomethionine, Cysteine, and Selenocysteine , Use of Simple, Efficient Modular Synthetic Reaction Schemes for Isotope Incorporation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2004
Arjan H. G. Siebum
Abstract Simple modular reaction schemes that allow access to any isotopomer of protected serine and homoserine have been worked out. These systems could be simply converted into cysteine, selenocysteine, homocysteine, homoselenocysteine, the essential amino acid methionine, and selenomethionine by Mitsunobu chemistry. These sulfur- and selenium-containing amino acids fulfil many essential roles in the living organism. In addition, homoserine could be converted in a few steps into optically active L -vinylglycine. As well as the stable isotopes 13C, 15N, 17O, and 18O, the radioactive isotopes of sulfur, selenium and carbon can also be easily introduced in a site-directed fashion. In view of the wide scope of the Mitsunobu reaction, we feel that many more important systems with the carbon skeleton of serine and homoserine should be preparable through this basic chemistry in any site-directed isotopically labeled form. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


Interpreting temporal variation in omnivore foraging ecology via stable isotope modelling

FUNCTIONAL ECOLOGY, Issue 4 2009
Carolyn M. Kurle
Summary 1The use of stable carbon (C) and nitrogen (N) isotopes (,15N and ,13C, respectively) to delineate trophic patterns in wild animals is common in ecology. Their utility as a tool for interpreting temporal change in diet due to seasonality, migration, climate change or species invasion depends upon an understanding of the rates at which stable isotopes incorporate from diet into animal tissues. To best determine the foraging habits of invasive rats on island ecosystems and to illuminate the interpretation of wild omnivore diets in general, I investigated isotope incorporation rates of C and N in fur, liver, kidney, muscle, serum and red blood cells (RBC) from captive rats raised on a diet with low ,15N and ,13C values and switched to a diet with higher ,15N and ,13C values. 2I used the reaction progress variable method (RPVM), a linear fitting procedure, to estimate whether a single or multiple compartment model best described isotope turnover in each tissue. Small sample Akaike Information criterion (AICc) model comparison analysis indicated that 1 compartment nonlinear models best described isotope incorporation rates for liver, RBC, muscle, and fur, whereas 2 compartment nonlinear models were best for serum and kidney. 3I compared isotope incorporation rates using the RPVM versus nonlinear models. There were no differences in estimated isotope retention times between the model types for serum and kidney (except for N turnover in kidney from females). Isotope incorporation took longer when estimated using the nonlinear models for RBC, muscle, and fur, but was shorter for liver tissue. 4There were no statistical differences between sexes in the isotope incorporation rates. I also found that N and C isotope incorporation rates were decoupled for liver, with C incorporating into liver tissue faster than N. 5The data demonstrate the utility of analysing isotope ratios of multiple tissues from a single animal when estimating temporal variation in mammalian foraging ecology. [source]


Convenient and efficient deuteration of functionalized aromatics with deuterium oxide: catalysis by cycloocta-1,5-dienyliridium(I) 1,3-dionates

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 13 2003
B. McAuley
Abstract Aromatic compounds bearing an ortho -directing substituent may be deuterated by exchange with deuterium oxide in the presence of a range of cycloocta-1,5-dienyliridium(I)1,3-dionate catalysts. The exchange takes place in several dipolar aprotic solvents and is directly applicable to the deuteration of polar compounds. Isotope incorporation is efficient and regiospecific. The method is applicable to a wide range of ortho -directing groups some of which are only weak directors for alternative ortho -labelling approaches. In addition, the application of microwaves enables labelling within minutes even with sub-stituents which are poor directors. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Microbial degradation of the biocide polyhexamethylene biguanide: isolation and characterization of enrichment consortia and determination of degradation by measurement of stable isotope incorporation into DNA

JOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007
L.P. O'Malley
Abstract Aims:, To isolate micro-organisms capable of utilizing polyhexamethylene biguanide (PHMB) as a sole source of nitrogen, and to demonstrate biodegradation of the biocide. Methods and Results:, Two consortia of bacteria were successfully enriched at the expense of PHMB, using sand from PHMB-treated swimming pools as inoculum. Both consortia were shown to contain bacteria belonging to the genera Sphingomonas, Azospirillum and Mesorhizobium. It was shown that the presence of both Sphingomonas and Azospirillum spp. was required for extensive growth of the consortia. In addition, the Sphingomonads were the only isolates capable of growth in axenic cultures dosed with PHMB. Using a stable isotope (15N),labelled PHMB, metabolism of the biocide by both consortia was demonstrated. By comparing the level of 15N atom incorporation into bacterial DNA after growth on either 15N-PHMB or 15N-labelled NH4Cl, it was possible to estimate the percentage of PHMB biodegradation. Conclusions:, The microbial metabolism of nitrogen from the biguanide moiety of PHMB has been demonstrated. It was revealed that Sphingomonas and Azospirillum spp. are the principal organisms responsible for growth at the expense of PHMB. Significance and Impact of the Study:, This is the first study to demonstrate the microbial metabolism of PHMB. [source]


Synthesis of the lipid peroxidation product 4-hydroxy-2(E)-nonenal with 13C stable isotope incorporation

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 2 2008
I. Jouanin
Abstract The aim of this work was to synthesize 13C internal standards for the quantification of 4-hydroxy-2(E)-nonenal (HNE), a lipid peroxidation product, and of the etheno-adducts possibly formed by HNE damage to DNA nucleobases. We designed an eight-step synthesis starting from ethyl 2-bromoacetate and giving access to 4-[(tetrahydro- 2H -pyran-2-yl)oxy]-2(E)-nonenal. This compound is a precursor of HNE. The scheme was then used to produce the 13C precursor [1,2- 13C2]-4-[(tetrahydro- 2H -pyran-2-yl)oxy]-2(E)-nonenal. [1,2- 13C2]-HNE was obtained by acid deprotection. All the intermediary and final compounds were fully characterized by IR, HRMS, 1H and 13C NMR. It is the first synthesis of HNE which enables the incorporation of two 13C labels at determined positions. Copyright © 2008 John Wiley & Sons, Ltd. [source]