Stable carbon and nitrogen isotope analysis reveals the diets of different human populations in history. In this study, we performed stable isotope analysis on human skeletons from Joseon-period cemeteries discovered around Old Seoul City (Hansung). Our data clearly showed that Joseon individuals consumed more C3-based than C4-based foods as the main staples, and that the proteins they ate were...

Ectomycorrhizal symbiosis is omnipresent in boreal forests, where it is assumed to benefit plant growth. However, experiments show inconsistent benefits for plants and volatility of individual partnerships, which calls for a re-evaluation of the presumed role of this symbiosis. We reconcile these inconsistencies by developing a model that demonstrates how mycorrhizal networking and market mecha...

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and...

The mechanism of the argininosuccinate lyase reaction has been probed by the measurement of the effects of isotopic substitution at the reaction centers. A primary deuterium isotope effect of 1.0 on both V and V/K is obtained with (2S,3R)-argininosuccinate-3-d, while a primary 15N isotope effect on V/K of 0.9964 +/- 0.0003 is observed. The 15N isotope effect on the equilibrium constant is 1.018...

Compound-specific stable isotope analysis (CSIA) of amino acids (AA) has rapidly become a powerful tool in studies of food web architecture, resource use, and biogeochemical cycling. However, applications to avian ecology have been limited because no controlled studies have examined the patterns in AA isotope fractionation in birds. We conducted a controlled CSIA feeding experiment on an avian ...

The isotopic composition of an element records information about its history. Given a fossil, it is possible to analyse the isotopic composition of the elements in the fossil and to use this to reconstruct the diet that the animal consumed. The process of dietary reconstruction, however, is far from simple. Biological systems are quite complex and can themselves introduce isotopic fractionation...

Genome annotation of the chlorinated ethene-respiring "Dehalococcoides ethenogenes" strain 195 indicated the presence of a complete nitrogenase operon. Here, results from long-term growth experiments, gene expression, and (15)N(2)-isotope measurements confirm that strain 195 is capable of fixing atmospheric dinitrogen when a defined fixed-nitrogen source such as ammonium is unavailable.

[reaction: see text] A large and normal nitrogen-15 kinetic isotope effect of 1.035 +/- 0.003 provides direct support for the proposed mechanism for the rhodium-catalyzed carbene formation from diazo compounds, which involves the fast formation of a metal-diazo complex followed by rate-limiting extrusion of N2. The large magnitude of the KIE indicates extensive C-N bond fission in the transitio...

Supplemental material available online. Soil Sci. Soc. Am. J. 79:1470–1481. doi:10.2136/sssaj2015.03.0101 Received 13 Mar. 2015 Accepted 13 July 2015. *Corresponding author ([email protected]). © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved. Influence of Forest Disturbance on Stable Nitrogen Isotope Ratios in Soil and Vegetation Profiles Forest, ...

Sulfur stable isotopes are increasingly being used as tracers of material processing in studies of both modern and historical food webs. Preparation of plant and animal material for isotope analysis routinely includes steps that remove inorganic material not normally assimilated by consumers. Whereas acidification of samples is known to assist with this for some elements (carbon), it can produc...