En este paper publicado en American Journal of Primatology presentamos un modelo matemático que predice los valores isotópicos de H y O en agua corporal y pelo de primates, y cotejamos las predicciones con muestras de animales bajo condiciones dietarias controladas.
Las mediciones de los isótopos de hidrógeno y oxígeno en tejidos biológicos se están convirtiendo en una herramienta muy importante en muchos tipos de estudios (migraciones, dispersión, estudios forenses, fisiología y evolución). Los átomos de hidrógeno y oxígeno en sistemas biológicos son mayormente derivados del agua embebida y del oxigeno atmosférico. Dado que los valores isotópicos de H y O en la precipitación y en el agua embebida varían en forma predecible a lo largo del paisaje, las mediciones de estos isótopos en el agua corporal de los animales y en la materia orgánica pueden ser usadas como marcadores de la región de origen. En este paper nosotros extendemos modelos mecanísticos previamente publicados para mostrar que variables como el agua, la dieta y las tasas metabólicas pueden ser usados de forma precisa para predecir los valores isotópicos del agua del cuerpo y del pelo de primates no humanos (monos cynomolgus). En este proyecto trabajamos con animales con dietas y agua controladas, lo que nos permitió constreñir varios parámetros nunca medidos en vertebrados. Este paper representa un paso mas en nuestros esfuerzos para lograr un entendimiento mas amplio sobre los factores metabólicos y dietarios que contribuyen a la variación de los isotopos de H y O en primates humanos y no humanos.
Hydrogen and Oxygen Isotope Ratios in Body Water and Hair: Modeling Isotope Dynamics in Nonhuman Primates.
Shannon P. O'Grady (1), Luciano O. Valenzuela (1), Christopher H. Remien, Lindsey E. Enright, Matthew J. Jorgensen, Jay R. Kaplan, Janice D. Wagner, Thure E. Cerling, James R. Ehleringer.
(1) The first two authors contributed equally to this paper, and are considered co-first authors.
Abstract: The
stable isotopic composition of drinking water, diet, and atmospheric
oxygen influence the isotopic composition of body water (2H/1H, 18O/16O expressed as δ2H and δ18O).
In turn, body water influences the isotopic composition of organic
matter in tissues, such as hair and teeth, which are often used to
reconstruct historical dietary and movement patterns of animals and
humans. Here, we used a nonhuman primate system (Macaca fascicularis) to test the robustness of two different mechanistic stable isotope models: a model to predict the δ2H and δ18O values of body water and a second model to predict the δ2H and δ18O
values of hair. In contrast to previous human-based studies, use of
nonhuman primates fed controlled diets allowed us to further constrain
model parameter values and evaluate model predictions. Both models
reliably predicted the δ2H and δ18O values of body
water and of hair. Moreover, the isotope data allowed us to better
quantify values for two critical variables in the models: the δ2H and δ18O values of gut water and the 18O isotope fractionation associated with a carbonyl oxygen–water interaction in the gut (αow).
Our modeling efforts indicated that better predictions for body water
and hair isotope values were achieved by making the isotopic composition
of gut water approached that of body water. Additionally, the value of αow was 1.0164, in close agreement with the only other previously measured
observation (microbial spore cell walls), suggesting robustness of this
fractionation factor across different biological systems. Am. J.
Primatol. 00:1–10, 2012.
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miércoles, 2 de mayo de 2012
martes, 15 de noviembre de 2011
Paper Nuevo: Hidrógeno y oxígeno en "carnes"
Nuevo paper publicado en Rapid Communications in Mass Spectrometry. En este paper, con mi colega Lesley A. Chesson como primer autora, describimos los valores isotópicos de muchas "carnes" (proteínas animales) disponibles para el consumo humano en distintas regiones de EEUU. Se describe la co-variación entre los isótopos de hidrógeno y oxígeno en estas proteínas como reflejo de la incorporación de los isótopos del agua y de su variación espacial.
Abstract:
Published datasets of proteinaceous animal tissues suggest that co-variation between amino acid hydrogen (δ2H) and oxygen (δ18O) isotope ratios is a common feature in systems where isotopic variation is driven by geographic or temporal variation in the δ2H and δ18O values of environmental water. This has led to the development of models relating tissue δ2H and δ18O values to those of water, with potential application in a number of fields. However, the strength and ubiquity of the influence of environmental water on protein isotope ratios across taxonomic groups, and thus the relevance of predictive models, is an open question. Here we report strong co-variation of δ2H and δ18O values across a suite of terrestrial and aquatic animal meats purchased in American food markets, including beef, poultry (chicken and turkey), chicken eggs, pork, lamb, freshwater fish, and marine fish. Significant isotope co-variation was not found for small collections of marine bivalves and crustaceans. These results imply that isotopic signals from environmental water were propagated similarly through most of the diverse natural and human-managed foodwebs represented by our samples. Freshwater fish had the largest variation in δ2H and δ18O values, with ranges of 121 ‰ and 19.2 ‰, respectively, reflecting the large isotopic variation in environmental freshwaters. In contrast marine animals had the smallest variation for both δ2H (7 ‰ range, crustaceans) and δ18O (3.0 ‰ range, bivalves) values. Known-origin beef samples demonstrated direct relationships between the variance of environmental water isotope ratios and that of collected meats. Copyright © 2011 John Wiley & Sons, Ltd.
Paper en Academia.edu
Paper en Wiley (publisher)
Abstract:
Published datasets of proteinaceous animal tissues suggest that co-variation between amino acid hydrogen (δ2H) and oxygen (δ18O) isotope ratios is a common feature in systems where isotopic variation is driven by geographic or temporal variation in the δ2H and δ18O values of environmental water. This has led to the development of models relating tissue δ2H and δ18O values to those of water, with potential application in a number of fields. However, the strength and ubiquity of the influence of environmental water on protein isotope ratios across taxonomic groups, and thus the relevance of predictive models, is an open question. Here we report strong co-variation of δ2H and δ18O values across a suite of terrestrial and aquatic animal meats purchased in American food markets, including beef, poultry (chicken and turkey), chicken eggs, pork, lamb, freshwater fish, and marine fish. Significant isotope co-variation was not found for small collections of marine bivalves and crustaceans. These results imply that isotopic signals from environmental water were propagated similarly through most of the diverse natural and human-managed foodwebs represented by our samples. Freshwater fish had the largest variation in δ2H and δ18O values, with ranges of 121 ‰ and 19.2 ‰, respectively, reflecting the large isotopic variation in environmental freshwaters. In contrast marine animals had the smallest variation for both δ2H (7 ‰ range, crustaceans) and δ18O (3.0 ‰ range, bivalves) values. Known-origin beef samples demonstrated direct relationships between the variance of environmental water isotope ratios and that of collected meats. Copyright © 2011 John Wiley & Sons, Ltd.
Chesson LA, Valenzuela LO, Bowen GJ, Cerling TE, Ehleringer JR. 2011 Consistent predictable patterns in the hydrogen and oxygen stable isotope ratios of animal proteins consumed by modern humans in the USA. Rapid Communications in Mass Spectrometry, 25(24) 3713-3722. doi: 10.1002/rcm.5283.
Paper en Academia.edu
Paper en Wiley (publisher)
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