Background and methodology:. The authenticity of organic products currently relies on enforcement of production standards through certification and inspection. As the organic market continues to increase, analytical tests that help maintain the authenticity of products in the organic sector should be considered. Synthetic nitrogen fertilizers used in conventional farming tend to have stable nitrogen isotope values close to zero, usually between -2 and 2‰. Organic manure is probably the most commonly applied source of nutrients in organic systems, which contains nitrogen isotope values between 10 and 20‰. This study collected samples of commercially produced organic and conventionally grown tomatoes, lettuce, and carrots and analyzed for their ä15N composition in order to assemble datasets to determine if there are any systematic differences in nitrogen isotope composition due to the method of production. Findings:. The tomato and lettuce datasets showed that the type of fertilizer used in ...

We are looking for a candidate with a strong interest in the development and application of analytical methods for the determination of stable nitrogen isotope signatures of dissolved nitrogen compounds (incl. NO3- and others) in seawater. The work is part of several subprojects of the SFB754 with the aim to decipher nitrogen pathways in the water column and in the benthic boundary layer of the eastern tropical South Pacific and tropical Atlantic Oceans.. ...

Author: Sealy, Judith et al.; Genre: Journal Article; Published in Print: 2014; Title: Comparison of two methods of extracting bone collagen for stable carbon and nitrogen isotope analysis: Comparing whole bone demineralization with gelatinization and ultrafiltration

TY - JOUR. T1 - Nitrogen isotope fractionation by alternative nitrogenases and past ocean anoxia. AU - Zhang, Xinning. AU - Sigman, Daniel Mikhail. AU - Morel, Francois M. M.. AU - Kraepiel, Anne M.L.. PY - 2014/4/1. Y1 - 2014/4/1. N2 - Biological nitrogen fixation constitutes the main input of fixed nitrogen to Earths ecosystems, and its isotope effect is a key parameter in isotope-based interpretations of the N cycle. The nitrogen isotopic composition (δ15N) of newly fixed N is currently believed to be∼-10/00, based on measurements of organic matter from diazotrophs using molybdenum (Mo)-nitrogenases. We show that the vanadium (V)- and iron (Fe)-only alternative nitrogenases produce fixed N with significantly lower δ15N (-6 to -70/00). An important contribution of alternative nitrogenases to N2 fixation provides a simple explanation for the anomalously low δ15N (,-20/00) in sediments from the Cretaceous Oceanic Anoxic Events and the Archean Eon. A significant role for the alternative ...

The δ15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ15N values. Regional differences in the δ15N values of phenylalanine confirmed that bulk tissue δ15N values reflect region-specific water mass biogeochemistry controlling δ15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP) for lanternfishes (family Myctophidae) (AA-TP ~2.9) largely align with expectations from stomach content studies (TP ~3.2), while AA-TPs for dragonfishes (family Stomiidae)

This article presents an overview of the history of Caribbean archaeological carbon and nitrogen stable isotope studies, a history that is paradoxically notable both for the precociousness of its first appearance and the subsequent dearth of large and meaningful studies. It provides a synopsis of the methodological underpinnings of paleodietary reconstruction by stable isotope analysis and discusses some of the unique challenges encountered in the use of this technique in Caribbean contexts. After reviewing some of the more meaningful studies of Caribbean archaeological materials, the article concludes with some thoughts on future prospects for the use of C and N stable isotope analysis for paleodietary reconstruction in archaeological research in the Caribbean Basin.

The International Tree-Ring Data Bank (ITRDB) is an invaluable resource, providing access to a massive and growing cache of tree-ring data. Oxygen, carbon, nitrogen and hydrogen isotope treering studies, which have provided valuable climatic and ecological information, have proliferated for decades so an ITRDB expansion to include isotopic data would likewise benefit the scientific community. An international tree-ring isotope databank (ITRIDB) would: (1) allow development of transfer functions from extended isotopic data sets, (2) provide abundant tree-ring isotopic data for meta-analysis, and (3) encourage isotopic network studies. A Europe network already exists, but the international data bank proposed here would constitute a de facto global network. Associated information to be incorporated into the database includes not only the customary ITRDB entries, but also elements peculiar to isotope chronologies. As with the current ITRDB, submission of data would be voluntary and as such it will ...

Previous attempts to evaluate age-at-weaning from nitrogen isotope data are reviewed and shown to suffer from two faults: treating the process of weaning as an event, and estimating weaning age without accounting for the influence of growth on the bodys nitrogen isotope ratios. In particular Schurrs (J. Archaeol. Sci. 24, 919-927, 1997) mathematical model for isotopic changes during weaning, is shown to use functions appropriate only for modelling an instantaneous switch in diet whilst maintaining a constant body weight.. This paper develops an improved model which takes account of the effect of changing body mass and an extended weaning period on the trajectory of isotopic change within juveniles. The model includes typical growth patterns for human infants, and a function which represents a gradual shift from sole dependence on the mothers milk to complete weaning. These are incorporated into isotope mass balance equations, which are then solved numerically. Comparison with longitudinal ...

Researchers from Brown University and the University of Washington have found a new way to make the link. The scientists show that comparing nitrogen isotopes in their deposited form - nitrates - can reveal the sources of atmospheric nitric oxide. In a paper published this week in Science, the group traces the source of nitrates to nitric oxides released through fossil fuel burning that parallels the beginning of the Industrial Revolution. The group also reveals that the greatest change in nitrogen isotope ratios occurred between 1950 and 1980, following a rapid increase in fossil fuel emissions.. What we find is there has been this significant change to the nitrogen cycle over the past 300 years, said Meredith Hastings, assistant professor of geological sciences at Brown and the papers lead author. So weve added this new source - and not just a little bit of it, but a lot of it.. ...

Chris Knowles of Oregon State University and I got into some SERIOUS chemistry last week. Lets see how it applies to the wood industry now.. Chris, you gave us a chemistry lesson last week. How do we USE this stable isotope analysis in the real world?. Among other uses, stable isotope analysis has a relatively long history of use for dating materials. Carbon dating provides an estimation of generally ±50 years for samples less than about 10,000 years old. However, the older the material, the less accurate the estimation will be. This estimate is based on a number of assumptions that may or may not be accurate. The bottom line is that this type of analysis will not identify the exact age of any material. It will only provide an estimate.. More recently, scientists have been exploring the potential to use the natural variability in stable isotopes by region to determine geographic origin of natural materials, including wood products. While the chemical analysis has a long history of use in other ...

We measure stable isotope ratios of carbon and nitrogen in organic matrix using conventional isotope ratio mass spectrometers. For a price offer, please contact the corresponding network partner. Animal tissue: --, Dr. Christian C. Voigt at: [email protected] Plant material: --, Dr. Zachary Kayler at: [email protected] Historic samples --, Dr. Ulrich Struck at: [email protected] ...

Found: The missing piece to solve the N isotope puzzle Prof. Dr. Ben Brunner, one of the three main authors, explains: We can answer this question with the help of stable nitrogen isotopes, by looking at the ratio between the stable isotopes 15N and 14N in the different pools of fixed N and in the produced N2, because different microbial processes leave different N isotope fingerprints; some prefer the light isotope 14N over the heavier isotope 15N, and others do the opposite. Dr. Sergio Contreras, a (paleo) biogeochemist interested in the past and future of the Nitrogen cycling, continues: However, the prerequisite to decipher the N isotope signatures in the environment is to know the isotope fingerprint of the individual nitrogen-loss processes. Prof. Dr. Moritz Lehmann, isotope biogeochemist from the University of Basel, adds: This is where so far, there was a gaping hole in our knowledge. The isotope effects of one major N-loss process, namely anammox, were unknown, and previous ...

Ashby, S. 2014 A Viking Way of Life, Stroud: Amberley.. Beaumont, J., Geber, J., Powers, N., Wilson, A., Lee-Thorp, J. and Montgomery, J. 2013 Victims and survivors: stable isotopes used to identify migrants from the great Irish famine to 19th century London, American Journal of Physical Anthropology 150. 87-98. http://dx.doi.org/10.1002/ajpa.22179. Bogaard, A., Heaton, T.H., Poulton, P. and Merbach, I. 2007 The impact of manuring on nitrogen isotope ratios in cereals: archaeological implications for reconstruction of diet and crop management practices, Journal of Archaeological Science 34(3). 335-343. http://dx.doi.org/10.1016/j.jas.2006.04.009. Brown, C. 2014 North and South: The isotopic analysis of four body tissues assessed alongside historical sources to reconstruct a comparative palaeodietary analysis of two post-medieval sites, Unpublished MSc thesis, University of York.. Commisso, R.G. and Nelson, D.E. 2010 Stable nitrogen isotopic examination of Norse sites in the Western ...

Ratios of nitrogen (N) isotopes in leaves could elucidate underlying patterns of N cycling across ecological gradients. To better understand global‐scale patterns of N cycling, we compiled data on foliar N isotope ratios (δ15N), foliar N concentrations, mycorrhizal type and climate for over 11 000 plants worldwide. Arbuscular mycorrhizal, ectomycorrhizal, and ericoid mycorrhizal plants were depleted in foliar δ15N by 2‰, 3.2‰, 5.9‰, respectively, relative to nonmycorrhizal plants. Foliar δ15N increased with decreasing mean annual precipitation and with increasing mean annual temperature (MAT) across sites with MAT ≥ −0.5°C, but was invariant with MAT across sites with MAT | −0.5°C. In independent landscape‐level to regional‐level studies, foliar δ15N increased with increasing N availability; at the global scale, foliar δ15N increased with increasing foliar N concentrations and decreasing foliar phosphorus (P) concentrations. Together, these results suggest that warm, dry

TY - GEN. T1 - Stable isotope analysis of breath using the optogalvanic effect. AU - Murnick, Daniel E.. AU - Colgan, M. J.. AU - Lie, H. P.. AU - Stoneback, D.. PY - 1996/1/1. Y1 - 1996/1/1. N2 - A new technique based on the optogalvanic effect has been developed for the measurement of stable isotope ratios in the carbon dioxide of exhaled breath. Data obtained before and after ingestion of harmless stable isotope labeled compounds, metabolized to carbon dioxide, can be used for sensitive noninvasive diagnostics of various disease conditions. The technique uses the specificity of laser resonance spectroscopy and achieves sensitivity and accuracy typical of sophisticated isotope ratio mass spectrometers. Using fixed frequency carbon dioxide lasers, 13C/ 12C ratios can be determined with a precision of 2 ppm with 100 second averaging times. Multiple samples can be analyzed simultaneously providing real time continuous calibration. In a first application, analysis of 13C/ 12C ratios in exhaled ...

Dual stable isotope analyses (delta 13C and delta 15N) of fiddler crabs from a forest-fringed, land-locked lagoon in Puerto Rico indicated the differential assim- ilation of material from ingested sediments. Fiddler crabs preferentially selected foi niitrogen-fixing benthic microalgae (cyanobacteria) over vascular plant detritus. These results question the assumption that mangrove detritus is always the prin- cipal source of energy to estuariiie consumers. Previous research fiom this lagoon as well as from Amazonia suggests that the magnitude of lan-d-wvater ecotonal coupling may be low for these particular tropical systems where benthic algal productivity is presumably high ...

Li, Yan, Zhong, Wenhe, Koay, Ann Zhufang, Ng, Hui Qi, Nah, Qianhui et al. 2019. Backbone resonance assignment for the full length tRNA-(N1G37) methyltransferase of Pseudomonas aeruginosa. Biomolecular NMR Assignments, 13 (2 ...

Close The Infona portal uses cookies, i.e. strings of text saved by a browser on the users device. The portal can access those files and use them to remember the users data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser. ...

STICKSTOFFORGANISCHE UMWELTSCHADSTOFFE; ABBAU, ZERSETZUNG, UMWANDLUNG, PERSISTENZ VON UMWELTSCHADSTOFFEN (UMWELTPROBLEME); TRIAZIN-DERIVATE (PESTIZIDWIRKSTOFFE); REDUKTION (CHEMISCHE REAKTIONEN); PHOTOCHEMISCHE REAKTIONEN (CHEMISCHE REAKTIONEN); ISOTOPIEEFFEKT (CHEMISCHE KINETIK); STICKSTOFF-15-ISOTOP; NITROGEN ORGANIC ENVIRONMENTAL POLLUTANTS; DEGRADATION, DECOMPOSITION, TRANSFORMATION, PERSISTENCE OF POLLUTANTS (ENVIRONMENTAL PROBLEMS); TRIAZINE-DERIVATIVES (PESTICIDE AGENTS); REDUCTION (CHEMICAL REACTIONS); PHOTOCHEMICAL REACTIONS (CHEMICAL REACTIONS); ISOTOPE EFFECT (CHEMICAL KINETICS); NITROGEN-15- ...

Backbone resonance assignment is a critical first step in the investigation of proteins by NMR. This is traditionally achieved with a standard set of experiments, most of which are not optimal for large proteins. Of these, HNCA is the most sensitive experiment that provides sequential correlations. …

Close The Infona portal uses cookies, i.e. strings of text saved by a browser on the users device. The portal can access those files and use them to remember the users data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser. ...

Sedimentary porewater chemical and isotopic profiles contain complex records of past bottom water composition which are overprinted by in situ biotic and abiotic reactions. We developed a density-based method to determined relic deep water salinities and applied it to map global scale water mass properties and distributions in the deep northwest Atlantic at four previously unsampled sites. Paleosalinities determined by density have higher precision and accuracy than previously published results and confirm the northward expansion of southern deep water and a reversal in the Atlantics bottom water meridional salinity gradient during the Last Glacial Maximum (Chapter 1 & 2). Nitrogen isotopic composition profiles of deeply buried porewaters are a unique dataset used to distinguish between biotic and abiotic nitrogen reactions under conditions that approach the canonical temperature and pressure limits of life. We attribute observed variations in nitrogen concentrations and isotopic compositions of

An isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic stable isotopes, stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry. This process is called isotope analysis. The atomic mass of different isotopes affect their chemical kinetic behavior, leading to natural isotope separation processes. For example, different sources and sinks of methane have different affinity for the 12C and 13C isotopes, which allows distinguishing between different sources by the 13C/12C ratio in methane in the air. In geochemistry, paleoclimatology and paleoceanography this ratio is called δ13C. The ratio is calculated with respect to Pee Dee Belemnite (PDB) standard: δ 13 C Sample = ( 13 C / 12 C Sample 13 C / 12 C P D B − 1 ) ⋅ 1000 {\displaystyle \delta ^{13}C_{\text{Sample}}=\left({\frac ...

The number-one guide, internationally, to all aspects of forensic isotope analysis, thoroughly updated and revised and featuring many new case studies This edition of the internationally acclaimed guide to forensic stable isotope analysis uses real-world examples to bridge discussions of the basic science, instrumentation and analytical techniques...

This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy profiles and pasture (grasses and shrubs) as well as corresponding carbon and nitrogen tissue concentrations in a number of different sites across Brazil. The sampling design captured the temporal variation in rainfall over the course of several years. Carbon and nitrogen isotope ratios can act as a proxy for interpreting aspects of the carbon and nitrogen cycles in Amazonian rainforests. Data are in three comma-delimited ASCII files. ...

Ammonium (NH4+ + NH3) is the optimal nitrogen source for E. coli (i.e., the source which yields most rapid growth). Ammonium (pKa = 9.25) enters cells in two forms (Fig. 1). NH3, which is ∼2% of total ammonium at pH 7.4, crosses the cell membrane by unmediated diffusion, a process that cannot be altered genetically. When the pH is decreased to 5.5, NH3 is only ∼0.02% of total ammonium. NH4+, which is the bulk of total ammonium at both pH 7.4 and pH 5.5, can enter the cells if and only if the AmtB channel is expressed and functional. Its expression is controlled at the transcriptional level and regulated largely by the free-pool concentration of glutamine in the cell interior (8), whereas its activity is controlled by the regulatory protein GlnK, largely in response to the free-pool concentration of the precursor metabolite 2-oxoglutarate, which is an intermediate in the tricarboxylic acid cycle (ref. 11 and references cited therein). Expression of AmtB increases as the glutamine ...

The project aims to characterize the effects of contrasted sources of organic matter (OM)and of mercury (Hg) on bioaccumulation of this metal for a key link of the marine food web: filter-feeding mollusks like mussels and oysters. Indeed, the...

Jonsson, E. and Boyce, A.J. (1999) Correlation of mineral parageneses with S and O isotopic variation in Pb-Mn-As-Sb-bearing veins at Langban, Sweden. In: Stanley, C.J. (ed.) Mineral Deposits: Processes to Processing, Vols 1 and 2. A.A. Balkema Publishers: Rotterdam, pp. 951-954. Full text not currently available from Enlighten. ...

Carbon and nitrogen isotope ratios in collagen from bones of individuals who lived in the Tehuacan Valley during the period 8000-1000 years B.P. have been interpreted as indicating earlier use of maize and more utilization of legumes as food sources than is suggested by the occurrence of the remains of these plants in the coprolites and debris excavated along with the bones. Reassessment of the assumptions made in interpreting the bone collagen isotope ratios reduces some but not all of the discrepancy between the isotopic and archaeological reconstructions of diet. The original archaeological reconstruction relied entirely on remains from cave sites, thus introducing seasonal and locational biases into the dietary reconstruction. Using the bone collagen isotope ratios as a guide, we re-interpreted the archaeological data to produce a more complete picture of temporal changes in the overall diet. We suggest that heavy dependence on grains began in the Coxcatlan phase and then may have remained ...

This study attempts to reconstruct food habits through carbon (C) and nitrogen (N) isotope analysis and C/N analysis of charred residues inside pottery from the Primorye in the Russian Far East (Luzanova Sopka 2, Sergeyevka 1, Boisman 2, and Vetka 2 sites). Dates were obtained that were from the later stages of the Rudnaya culture (6980-6485 BP, 7800-7400 cal BP), proto-Boisman type (6760-6330 BP, 7600-7300 cal BP), Boisman culture (6155-4720 BP, 7100-5400 cal BP), and Vetka culture (6030-5870 BP, 6900-6700 cal BP). There are major differences in the carbon and nitrogen isotope ratios between inland sites (δ13C -26.9 to -30.0‰, δ15N 7.6 to 9.3‰) and coastal sites (δ13C -18.1 to -24.2‰, δ15N 9.5 to 14.9‰). The results show that the diet of inland cultures consisted primarily of freshwater fish and terrestrial animals and plants, whereas that of coastal cultures consisted mainly of marine organisms.. ...

Measurements of carbon (13C/12C; δ13C) and nitrogen (15N/14N; δ15N) stable isotope ratios have become important tools for: estimating energy flow and trophic positions in aquatic foodwebs; comparing food webs; and aiding in the tracking of wide-ranging consumers. However, each of these applications requires accurate measurements of isotopic signatures in organisms at or near the base of the food web (e.g. autotrophs and their consumers), which act as basal reference points from which to calibrate inferences. Therefore, understanding variations in isotopic baselines, and the mechanisms leading to their variability, is crucial for food web ecology. Using the shallow temperate reefs along the lower west coast of Australia as a test case, the broad aim of this thesis was to determine isotopic variations in a coastal food web and their relationship with surrounding environmental factors or food sources, to determine the suitability and issues for using such baselines in interpreting trophic links and

TY - JOUR. T1 - Vertical sheep mobility along the altitudinal gradient through stable isotope analyses in tooth molar bioapatite, meteoric water and pastures: A reference from the Ebro valley to the Central Pyrenees. AU - Tornero, Carlos. AU - Aguilera, Mónica. AU - Ferrio, Juan Pedro. AU - Arcusa, Héctor. AU - Moreno-García, Marta. AU - Garcia-Reig, Sheila. AU - Rojo-Guerra, Manuel. PY - 2018/8/10. Y1 - 2018/8/10. N2 - © 2016 Elsevier Ltd and INQUA Although the frequency of pastoral activities involving vertical sheep mobility has decreased over the last century, this is a herding strategy still used in the Ebro basin, where animals move from overwintering valley locations up to the Pyrenees from late spring to early autumn. Such practice allows herders to avoid the worst climatic conditions, seasonally balancing the great contrast between ecological zones in this region, from dry lowland Mediterranean steppe to wet mountain subalpine grasslands. As recent regional archaeological works have ...

Mintenbeck, K. , Brey, T. , Jacob, U. , Knust, R. and Struck, U. (2008): How to account for the lipid effect on carbon stable isotope ratio (d13C) - sample treatment effects and model bias , Journal of Fish Biology ...

Aleut population history has been a topic of debate since the earliest archaeological investigations in the region. In this paper, we use stable isotope chemistry to evaluate the hypothesis that two distinct groups of people, Paleo- and Neo-Aleut, occupied the eastern Aleutians after 1000 BP. This study focuses on 80 sets of directly dated eastern Aleutian burial assemblages from Chaluka midden, Shiprock Island and Kagamil Island. We use a linear mixing model informed by isotopic analysis of two large Aleut faunal assemblages to address temporal and spatial variation in human carbon and nitrogen stable isotope data from these sites. The patterning we report addresses both Aleut demographic and economic prehistory, illustrating a transition in both at ca. 1000 BP. Our results suggests that the Chaluka diet, dominated by Paleo-Aleut inhumations, differed in both trophic level and foraging location from the other two sites for much of the past 4000 years. Trends in our data also suggest that individuals

en] The ampG gene codes for a permease required to uptake anhydro-muropeptides into bacterial cytoplasm. Located upstream in the same operon, is another 579-base-pair-long open reading frame encoding a putative lipoprotein YajG, whose nearly complete 1H,13C,15N assignments are reported here ...

In all taxa where sexes were known, d15N data implied that males foraged at a higher trophic level. We believe this latter result is linked to a dual foraging strategy among females. With South Georgian shags we found the sex-related dietary differences persisted for long periods (inferred from stable isotope analyses of feathers and blood). We suggest that the trophic differences are driven by differences in physiological performance, with males tending to dive deeper than females because of their size and accessing higher trophic level prey items. Moreover male and female shags tend to forage at different times of day and so the observed differences are unlikely to be driven by the social dominance of males. Highly significant relationships between stable isotope signatures in blood (representing the breeding season diet) and those in feathers (mostly representing the non-breeding season diet) in both the South Georgian and Kerguelen shags suggests that these two taxa comprise individuals that ...

WEST LAFAYETTE, Ind. The food buried with King Midas around 700 B.C., along with the king himself, may have fueled a feast for a generally benign type of fungus that led to extensive deterioration of the kings tomb, a new study shows.. Timothy Filley, assistant professor of biogeochemistry at Purdue University, led a study that combined stable nitrogen isotope analysis and microscopy of wood samples from the tomb to gather information on the kings diet and determine the nutrient sources for the fungi that destroyed much of the contents of the tomb and human remains.. The findings, published in the Oct. 30 issue of the Proceedings of the National Academy of Sciences, may explain why many artifacts within the tomb have deteriorated, despite the fact they were constructed of decay-resistant wood, Filley says.. The structural and chemical signatures of the decay, which is heaviest where the body was laid and on the tabletops surrounding the coffin, indicates that the fungus was fueled by nitrogen ...

Read A 13C-detected 15N double-quantum NMR experiment to probe arginine side-chain guanidinium 15Nη chemical shifts, Journal of Biomolecular NMR on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

A computer program (SHIFTX) is described which rapidly and accurately calculates the diamagnetic 1H, 13C and 15N chemical shifts of both backbone and sidechain atoms in proteins. The program uses a hy

The search for early Earth biological activity is hindered by the scarcity of the rock record. The very few exposed sedimentary rocks have all been affected by secondary processes such as metamorphism and weathering, which might have distorted morphological microfossils and biogenic minerals beyond recognition and have altered organic matter to kerogen. The search for biological activity in such rocks therefore relies entirely on chemical, molecular or isotopic indicators. A powerful toot used for this purpose is the stable isotope signature of elements related to life (C, N, S, Fe). It provides key informations not only on the metabolic pathways operating at the time of the sediment deposition, but more globally on the biogeochemical cycling of these elements and thus on the Earths surface evolution. Here, we review the basis of stable isotope biogeochemistry for these isotopic systems. Rather than an exhaustive approach, we address some examples to illustrate how they can be used as ...

Oecologia, 110, 120-131.. Buchmann, N., Kao, W.-Y., Ehleringer, J., (1997b) Influence of stand structure on carbon-13 of vegetation, soils and canopy air within deciduous and evergreen forests in Utah, United States. Oecologia, 110, 109-119.. Delwiche, C.C., Steyn, P.L., (1970) Nitrogen isotope fractionation in soils and microbial reactions. Environmental Science and Technology, 4(11), 929-935.. Derrien, D., Baldesdent, J., Moral, C., Santaella, C., (2003) Measurement of the 13C/12C ratio of soil-plant individual sugars by gas chromatography/combustion/isotope-ratio mass spectrometry of silylated derivatives. Rapid Communications in Mass Spectrometry, 17, 2626-2631.. Ehleringer, J.R., Field, C.B., Lin, Z.F., Kuo, C.Y., (1986) Leaf carbon isotope ratio and mineral composition in subtropical plants along an irradiance cline. Oecologia, 70, 520-526.. Feng, X., Epstein, S., (1995) Carbon isotopes from arid environments and implications for reconstructing atmospheric ...

Stable isotope ratio variation in natural systems reflects the dynamics of Earth systems processes and imparts isotope labels to Earth materials. Carbon isotope ratios of atmospheric CO2 record exchange of carbon between the biosphere and the atmosphere; the incredible journeys of migrating monarchs is documented by hydrogen isotopes in their wings; and water carries an isotopic record of its source and history as it traverses the atmosphere and land surface. Through these and many other examples, improved understanding of spatio-temporal isotopic variation in Earth systems is leading to innovative new approaches to scientific problem-solving. This volume provides a comprehensive overview of the theory, methods, and applications that are enabling new disciplinary and cross-disciplinary advances through the study of isoscapes: isotopic landscapes. This impressive new volume shows scientists deciphering and using the natural isotope landscapes that subtly adorn our spaceship Earth., Brian Fry, ...

Maize seedlings were grown on either nitrate or ammonium, at two different potassium levels, and the growth analysis revealed that ammonium supply reduced shoot dry matter particularly under conditions of limited potassium supply. The ammonium content of the leaves was determined in vitro, using continuous flow analysis of plant extracts, and in vivo using 14 N nuclear magnetic resonance (NMR) spectroscopy. The conventional continuous flow analysis procedure was modified by the inclusion of a gas dialysis step across a PTFE membrane and control experiments showed that this provided an effective method for avoiding the overestimation of the ammonium content of leaf tissue extracts, by eliminating interference from amino acids and amides. Excellent agreement was obtained between the non-invasive NMR method and the modified continuous flow analysis technique, and it was concluded that leaf ammonium levels are unlikely to affect growth in plants grown with an adequate potassium supply. © 1995 Kluwer

The transforming growth factor beta induced protein (TGFBIp) is a major protein component of the human cornea. Mutations occurring in TGFBIp may cause corneal dystrophies, which ultimately lead to loss of vision. The majority of the disease-causing mutations are located in the C-terminal domain of T …

Ca2+-Calmodulin binding to the variable N-terminal region of the diacylglycerol/phorbol ester-binding UNC13/Munc13 family of proteins modulates the short-term synaptic plasticity characteristics in ne

Distributions of stable isotopes have been used to infer an organisms trophic niche width, the isotopic niche, and examine resource partitioning. Spatial variation in the isotopic composition of prey may however confound the interpretation of isotopic signatures especially when foragers exploit resources across numerous locations. In this study the isotopic compositions from marine assemblages are modelled to determine the role of variation in the signature of prey items and the effect of dietary breadth and foraging strategies on predator signatures. Outputs from the models reveal that isotopic niche widths can be greater for populations of dietary specialists rather than for generalists, which contravenes what is generally accepted in the literature. When a range of different mixing models are applied to determine if the conversion from δ to p-space can be used to improve model accuracy, predator signature variation is increased rather than model precision. Furthermore the mixing models applied

Stable isotope ratios of hydrogen and oxygen are widely used in hydrology, biology, chemistry, environmental sciences, food and drug authentication,

This study integrates bone collagen stable isotope data(carbon, nitrogen and sulphur) from 33 human adult tibiae (15 females;18 males) and 13 faunal remains from Tomar, while it was under the Military Orders domain (eleventh-seventeenth centuries). Historical literature indicates that the amount of meat consumption amongst Templars was lower than in individuals with similar social status. In Medieval times,these Military Orders had total control of towns and angling and fishing rights, but their influence on the general population diet remains unknown. While no statistically significant differences (p,0.05) were found between sexes, social status, or for bone collagen δ13C and δ34S between age groups, δ15N did differ significantly with age, which may be related to tooth loss in old individuals. Additionally, the human samples have higher stable isotope differences, in comparison with faunal samples, than would be expected within the food web, particularly for δ13C. This human bone collagen ...

To investigate the scale, and to determine the origin of the nitrogen isotope heterogeneity (source vs. fractionation during diamond-formation) shown for populations of mantle diamonds we have determined multiple δ13C-δ15N values and nitrogen abundances from 14 monocrystalline (MCDs) and 25 polycrystalline diamonds (PCDs) using step-wise oxidation gas sourced mass spectrometry. These data show that the heterogeneity shown for carbon and nitrogen isotope values from single diamond samples presented here is typically ,5‰ and ,8‰ respectively, both of which are comparable to the standard deviation for the mean mantle δ13C and δ15N values (±3 and ±4‰). However, there are samples that show much larger heterogeneities for δ13C and δ15N values (≤ 23‰ and ≤ 33‰ respectively), which cannot be generated by equilibrium stable isotope fractionation during, or prior to diamond-formation. These data suggest that isotopic heterogeneity may be present within the diamond-forming fluid on ...

Article Estimation of nitrogen stable isotope turnover rate of Oncorhynchus nerka. Estimation of the isotopic turnover rate in the tissues of organisms allows us to estimate the temporal relationship between the isotope ratio of an organism and its p...

Comparative studies on manual and automatic backbone chemical shift assignments of 2H-13C-15N-labeled Ube2g1. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.

Nicole is interested in developing new applications of stable isotopes and other source-sink tracers to the study of plants and mycorrhizal fungi. For her Ph.D she focused mainly on the use of stable isotopes to examine mycoheterotrophic food-webs. The physiology of mycoheterotrophic plants remained nearly entirely unexplained until the relatively recent application of stable isotope analyses to plant ecology. The analysis of the natural abundance of carbon (13C:12C) and nitrogen (15N:14N) stable isotopes in plants are powerful tools to infer strategies of resource acquisition and metabolic pathways in plants. The stable isotope signatures of mycoheterotrophic plants seem to best fit an isotope food-chain model where the plants stable isotope signatures reflect those of their host fungi, their ultimate nutrient source. Generally, the source of a nutrient is left depleted in the heavy isotope compared to its sink. For instance, previous work has shown that fully mycoheterotrophic plants that ...

In the Southern part of Hanoi, high ammonium (NH4+) concentrations in reducing groundwater have been an issue over the last 25 years. Elevated NH4+ concentrations in groundwater, in general, are an indicator of influences from anthropogenic sources, but the buried peat layers in the Red River delta formation are also hypothesized to contribute to the high NH4+ levels (up to 100 mg/l). We traced the sources of NH4+ at the Nam Du well field of the Hanoi water works by means of isotope ratios (N-15/N-14). The delta N-15 values were determined for total sedimentary N and exchangeable NH4+ of the peat material, and for NH4+ dissolved in deep and shallow groundwater, sewage, and surface water. Groundwater NH4+ of the upper (Holocene) and the lower (Pleistocene) aquifers had higher delta N-15 values than did total N and NH4+ of the sediments, and were somewhat higher than the delta N-15 values of NH4+ in sewage and surface water. We conclude that the present conditions of temperature and pH tend to ...

As many of you have heard, I have a project in the 4th SciFund Challenge, a scientific research crowdfunding organization. My project, entitled You are what you eat: non-lethal feeding ecology to help conserve threatened sharks, is part of my Ph.D. dissertation research. Youll be hearing a lot more about it over the new few weeks here, on twitter, and on my Facebook page once the challenge officially starts on February 1st. Id really appreciate your support of my research!. Ill be using a research technique called stable isotope analysis to study the diet and food web interactions of shark species in Florida. My project (and the research technique) will be briefly explained on my SciFund site, but I wanted to go into more detail about the type of research questions that stable isotope analysis can answer, as well as why this kind of data is significant.. Feeding ecology is important to the conservation and management of sharks.. An emerging trend in marine conservation is ecosystem based ...

The hydrothermal vent zoarcid fish Thermarces cerberus is a top predator that inhabits deep-sea hydrothermal vents on the East Pacific Rise (EPR). Bacterial chemoautotrophy at these sites supports abundant animal communities. Paradoxically, these chemoautotrophic bacteria are not known to produce polyunsaturated fatty acids (PUFA), dietary nutrients essential for all marine vertebrates. To understand how T cerberus successfully exploits the vent environment and obtains essential PUFA, we compared its fatty acid composition to those of its invertebrate prey. Levels of 20 : 5(n - 3) and 22 : 6(n - 3) in muscle and ovary tissues of T. cerberus were low and contained higher amounts of 20 : 5(n - 3) than 22 : 6(n - 3). This is in contrast to most marine fish where 22 : 6(n - 3) typically dominates. Prey items include the limpet (Lepetodrilus elevates) and amphipods (Halice hesmonectes and Ventiella sulfuris) and all contained PUFA dominated by 20: 5(n - 3) in amounts likely to support the ...

Compound-specific isotope analyses are a very promising method for reconstructing aspects of past diets, especially by combining nitrogen and carbon isotope analyses on single amino acids to clearly distinguish aquatic and terrestrial sources of proteins, and to estimate with more precision the contribution of plants in individual diets. Our application of CSIA to two Neandertals has shown that both were high trophic level consumers, with large herbivores being the main protein source. Therefore, there is no reason to invoke myriad dietary interpretations such as the consumption of mushrooms, putrid animal flesh, mammoths, or freshwater fish to explain their high bulk bone collagen nitrogen isotope values of Neandertals in relation to carnivores from the same site. However, we acknowledge that our isotopic study does not rule out the occasional consumption of these foods. Instead, the differing high N values between Neandertals and associated carnivores is likely due to the consumption of ...

The chitin-active 19.2 kDa lytic polysaccharide monooxygenase BlLPMO10A from Bacillus licheniformis has been isotopically labeled and recombinantly expressed. In this paper, we report the 1H, 13C, 15N resonance assignment of BlLPMO10A ...

In large lakes around the world, shifts in ecological communities are often associated with water depth. This suggests that there may be concomitant changes in patterns of resource allocation. Using Lake Superior as an example, we explored this idea through stable isotope analyses of 14 major fish taxa. Patterns in carbon and nitrogen isotope ratios revealed use of littoral and profundal benthos among individuals of most taxa analyzed. Use of benthos was strongest among nearshore demersal species and weakest among planktivores, and declined with depth of habitat. Isotope mixing model results indicated that benthic food web pathways were most important in nearshore fish species, whereas offshore pelagic and profundal species used planktonic pathways. These patterns appear to be governed by two key processes: high benthic production in nearshore waters and diel vertical migration among offshore invertebrates and fish. These characteristics are shared with the Great Lakes of Africa, Russia, and ...

The biosynthesis of the opine agropine in transformed Nicotiana tabacum L. root cultures was studied using in vivo 15N nuclear magnetic resonance (NMR) spectroscopy. Roots were incubated with [15N]ammonium and/or [15N]nitrate, and the incorporation of the label into agropine, conjugated polyamines, γ-aminobutyric acid (GABA), glutamate (Glu), glutamine (Gln) and nicotine was monitored by NMR. The largest labelled pool was agropine in cells grown on a 15N-enriched medium and its synthesis was maintained, to the detriment of the Gln pool, under conditions of nitrogen (N) starvation. These observations indicate that the synthesis of agropine is not tightly regulated and that it represents a significant sink for carbon (C) and N in the plant. The addition of α-naphthaleneacetic acid (NAA) and kinetin to the growth medium caused de-differentiation of the root cultures and perturbation of secondary N metabolism. The amount of agropine relative to Gln increased but the total accumulation of agropine

This study analyses the response of the carbon and nitrogen isotopic composition of sedimentary organic matter to rapid human-induced eutrophication and meromixis as well as subsequent restoration efforts [in-lake phosphorus (P)-Precipitation, P-remediation of the well inflow and multiannual destratification] in a 46-yr sediment core sequence (1963-2009) from Fischkaltersee, a small hard-water lake (S-Germany). In addition, the sediment record was compared with detailed data on water column chemistry during almost (1977-2009) the recorded history of eutrophication and trophic recovery of the named lake. While the onset of eutrophication resulted in an abrupt positive excursion (+2.4‰), the overall reaction of δ13CSOM to ongoing eutrophication and meromixis as well as to permanent hypolimnion aeration and trophic recovery is a continous negative trend (-3.7‰) with the most depleted signatures (-38.8‰) present in the youngest part of the core. This negative trend was not influenced by ...

Fingerprint Dive into the research topics of Variability of the ,sup,15,/sup,N chemical shift anisotropy in Escherichia coli ribonuclease H in solution. Together they form a unique fingerprint. ...

The usefulness of Stable Isotope Analysis in Archaeology (Theme 3-Subsistence and diet). Key facts:. · Every chemical in nature has isotopes.. · The main difference is their atomic mass.. · Different isotopes have different amounts of protons and neutrons but still remain stable.. · C14 is an unstable isotope due to the radioactive nature of the neutrons and protons.. · This means that whilst C14 decays at the rate of the half life, stable isotopes do not decay so are useful in the archaeological record.. · Key isotopes to analyse: Carbon, Nitrogen and Sulphur-all link to diet.. · Analysis takes place using collagen (bone) or tooth enamel.. How do discuss it within an essay:. 1. When food is eaten and digested it already has a carbon and/or nitrogen trace within it.. 2. Human bones reflect the amount of plants ingested during the lifetime based on the C13 ratio.. 3. The nitrogen ratio can distinguish which plants were or were not eaten at a particular time in prehistory.. 4. Analysing the ...

ABSTRACT: In 2007 a ceremonial complex representing the Globular Amphora Culture was discovered in Kowal (the Kuyavia region, Poland). Radiocarbon dating demonstrated that the human remains associated with the complex are of similar antiquity, i.e. 4.105 ± 0.035 conv. and 3.990 ± 0.050 conv. Kyrs. After calibration, this suggests a period between 2850 and 2570 BC (68.2% likelihood), or more specifically, 2870 to 2500 BC (95.4% likelihood). Morphological data indicate that the skeleton belonged to a male who died at 27-35 years of age. The unusual morphology of his hard palate suggests this individual may have had a speech disorder. Stable oxygen isotope values of the individuals teeth are above the locally established oxygen isotope range of precipitation, but due to sample limitations we cannot conclusively say whether the individual is of non-local origin. Stable carbon and nitrogen isotope ratios were analyzed to reconstruct the diet of the studied individual, and show a terrestrial-based ...

Background. The pattern of protein intake following exercise may impact whole-body protein turnover and net protein retention. We determined the effects of different protein feeding strategies on protein metabolism in resistance-trained young men. Methods. Participants were randomly assigned to ingest either 80g of whey protein as 8x10g every 1.5h (PULSE; n=8), 4x20g every 3h (intermediate, INT; n=7), or 2x40g every 6h (BOLUS; n=8) after an acute bout of bilateral knee extension exercise (4x10 repetitions at 80% maximal strength). Whole-body protein turnover (Q), synthesis (S), breakdown (B), and net balance (NB) were measured throughout 12h of recovery by a bolus ingestion of [15N]glycine with urinary [15N]ammonia enrichment as the collected end-product. Results. PULSE Q rates were greater than BOLUS (~19%, P Conclusion. We conclude that the pattern of ingested protein, and not only the total daily amount, can impact whole-body protein metabolism. Individuals aiming to maximize NB would likely ...

Imbrie, John D; McIntyre, Andrew; Mix, Alan C (1997): Stable isotope data (adjusted) of sediment core RC13-228 (specmap.003). PANGAEA, https://doi.org/10.1594/PANGAEA.52118

Compound-specific carbon and hydrogen isotope ratios are routinely measured on extractable organic matter to decipher biogeochemical processes and events in Earth history. To deliver accurate interpretations, it is paramount that isotopic values are derived from indigenous compounds and are not the result of contamination. However, distinguishing between compounds from these different provenances can be difficult, especially if a degree of mixing occurred. In this study, we assess the impact of hydrocarbon contamination on the carbon and hydrogen isotopic composition of n-alkanes from similar to 820 Ma Precambrian evaporitic drill core samples through exterior/interior (E/I) rock extraction experiments. In these experiments, exterior and interior portions of the same rock samples were separately crushed to powder, extracted and processed. Compound-specific isotope values of n-alkanes from the different rock portions were subsequently measured and compared. In most cases, n-alkanes from exterior ...

In the last year, the stable isotope ratio analysis has become a useful tool with many applications in different scientific area. In particular the characteristic isotope signature of materials has permitted to identify authenticity and traceability of food sample and isotope composition has become a valuable marker in environmental studies. This work shows the applicability of analytical methods for isotopic carbon determination in food and environmental samples and the innovative use of δ13C in cultural heritage as valuable tool to trace pollutant fate. The first part is dedicated to the improvement of spectroscopic methods as Fourier Transform Infrared (FT-IR) and Non-Dispersive Infrared spectroscopy (NDIRS) and their application to identify geographical origin in sample like pasta, cocoa, olive oil. The results conducted in order to assess the robustness of the two alternative methods respecting IRMS showed a strong correlation like a demonstration of the positive relationship between the ...

On Australian semiarid floodplains, large herbivores such as kangaroos have a role in the cycling of energy (carbon) through the mechanism of feeding and defaecation of vegetative material. The degree to which kangaroos are vectors of energy within this system is not fully understood. This study describes the stable carbon isotope signature of floodplain plants and kangaroo scats at two close study sites. Kangaroos were found to deposit scats that mirrored the forage composition at each particular feeding site. Scats were 3.94‰ higher in δ13C values at the site where C4 grasses were available, indicating that this grass contributed ~25-30% of the diet of these kangaroos. The difference in diet due to the relative availability of C3 and C4 forage, detectable in the carbon stable isotope signature of scats, is used to demonstrate that kangaroos are recycling and redistributing energy locally, rather than transporting it more broadly across the floodplain. © 2010, CSIRO ...

Résumé: Stable isotope ratios for six size fractions of zooplankton (80 to >2000 μm) were analyzed in the Gulf of Lion in spring 2010 and winter 2011. Environmental and plankton community variables were also recorded. The originality of this study is the use of a Lagrangian transport modeling system to determine the origin of the water masses and the assessment of the proportion of detritus in the plankton samples. The highest δ15N values were observed in the 1000-2000 μm fraction in January and in the 500-1000 μm fraction in May. The largest size class (>2000 μm), dominated by salps, had lower δ15N values owing to the low isotopic signatures of these organisms. The history of the water masses resulted in two main patterns with different isotopic signatures: the water masses which resided on the shelf and the waters masses carried onto the shelf from off-shelf region by the Northern Current. The δ13C values varied strongly between January and May, mainly owing to changes in hydrographic ...

Otoliths of king threadfin, Polydactylus macrochir were collected from 2007 to 2009 at nine locations across northern Australia representing most of their distributional range and areas where fisheries are active. Measurement of the stable isotope ratios of δ18O and δ13C in the sagittal otolith carbonate from assemblages of P. macrochir revealed location-specific signatures and indicated that adult fish sampled from representative sites across their range were significantly different. The significant differences in the isotopic signatures of P. macrochir demonstrated that population subdivision is evident and there is unlikely to be substantial movement of fish among these distinct adult assemblages. The stable isotopic signatures for the fish from the different locations were persistent through time, and therefore it could be concluded that they comprise separate stocks for many of the purposes of fisheries management. The spatial separation of these populations indicates a complex stock ...

Abstract. The balance between denitrification and nitrogen fixation is the key control of the availability of nitrogen in coastal ecosystems and thus the primary productivity of these environments. However, evaluating the importance of denitrification and nitrogen fixation over large spatial and temporal scales is problematic. In this study, a combined mass and stable isotope balance of nitrogen was used to constrain the cycling of nitrogen in Western Port, Victoria - a temperate, intertidal embayment in south-eastern Australia. This method is a more effective approach compared to the extrapolation of discrete measurements and geochemical approaches. The validity of the isotope and mass balance model has been tested by comparing the output of the model with the average measured isotopic signature of the sediment in Western Port. Using previously measured rates of nitrogen fixation and denitrification in combination with the isotopic signature of nitrogen inputs from the catchment, atmosphere and ...

Aerosol nitrate is an important fraction of the mass of the fine particles (PM) in atmosphere. Moreover, aerosol nitrogen species are predominantly anthropogenic over Europe (traffic, industry and farming). In the view of the increasingly drastic constraints of the European air quality standard for PM, the understanding of these sources has become crucial in France. Indeed, during the months of March and April, several high concentration of PM are observed on a large scale throughout the national territory. During these specific events, the ammonium nitrate (NH4NO3) is a predominant component of the airborne PM. There are two main ways that produces NH4NO3 in air with many precursors as NH3 from specific primary sources (agricultural activity). The presence of these species in PM is the result of complex primary and secondary processes which are always investigated. In literature, many studies propose the nitrogen stable isotope ratio (?15N) of NOx as an indicator for NOx source apportionment ((Walters,

TY - JOUR. T1 - Chemical shift assignments of the C-terminal Eps15 homology domain-3 EH domain. AU - Spagnol, Gaelle. AU - Reiling, Calliste. AU - Kieken, Fabien. AU - Caplan, Steve. AU - Sorgen, Paul L.. PY - 2014/10/1. Y1 - 2014/10/1. N2 - The C-terminal Eps15 homology (EH) domain 3 (EHD3) belongs to a eukaryotic family of endocytic regulatory proteins and is involved in the recycling of various receptors from the early endosome to the endocytic recycling compartment or in retrograde transport from the endosomes to the Golgi. EH domains are highly conserved in the EHD family and function as protein-protein interaction units that bind to Asn-Pro-Phe (NPF) motif-containing proteins. The EH domain of EHD1 was the first C-terminal EH domain from the EHD family to be solved by NMR. The differences observed between this domain and proteins with N-terminal EH domains helped describe a mechanism for the differential binding of NPF-containing proteins. Here, structural studies were expanded to include ...

Background: Information on larval diet of many holometabolous insects remains incomplete. Carbon (C) and nitrogen (N) stable isotope analysis in adult wing tissue can provide an efficient tool to infer such trophic relationships. The present study examines whether moth feeding guild affiliations taken from literature are reflected in isotopic signatures. Results: Non-metric multidimensional scaling and permutational analysis of variance indicate that centroids of dietary groups differ significantly. In particular, species whose larvae feed on mosses or aquatic plants deviated from those that consumed vascular land plants. Moth δ15N signatures spanned a broader range, and were less dependent on species identity than δ13C values. Comparison between moth samples and ostensible food sources revealed heterogeneity in the lichenivorous guild, indicating only Lithosia quadra as an obligate lichen feeder. Among root-feeding Agrotis segetum, some specimens appear to have developed on crop plants in ...

Background: Information on larval diet of many holometabolous insects remains incomplete. Carbon (C) and nitrogen (N) stable isotope analysis in adult wing tissue can provide an efficient tool to infer such trophic relationships. The present study examines whether moth feeding guild affiliations taken from literature are reflected in isotopic signatures. Results: Non-metric multidimensional scaling and permutational analysis of variance indicate that centroids of dietary groups differ significantly. In particular, species whose larvae feed on mosses or aquatic plants deviated from those that consumed vascular land plants. Moth δ15N signatures spanned a broader range, and were less dependent on species identity than δ13C values. Comparison between moth samples and ostensible food sources revealed heterogeneity in the lichenivorous guild, indicating only Lithosia quadra as an obligate lichen feeder. Among root-feeding Agrotis segetum, some specimens appear to have developed on crop plants in ...

We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope (15NO) detection sensitivity of 0.36 ppbv·Hz−1/2, corresponding to noise-equivalent Faraday rotation angle (NEA) of 1.31 × 10−8 rad·Hz−1/2 and noise-equivalent absorbance (αL)min of 6.27 × 10−8 Hz−1/2. White-noise limited performance at 2.8× the shot-noise limit is observed up to ~1000 s, allowing reliable calibration and sample measurement within the drift-free interval of the spectrometer. Integration with wet-chemistry based on acidic vanadium(III) enables conversion of aqueous nitrate/nitrite samples to gaseous NO for total nitrogen isotope analysis. Isotopic ratiometry is accomplished via time-multiplexed measurements of two NO isotope transitions. For 5 μmol potassium nitrate samples, the

A team of researchers found something rather peculiar tucked in the dental tartar of a Mesolithic forager from the 8th millennium B.C., who was excavated from Vlakno Cave on the Croatian island of Dugi Otok. Using carbon and nitrogen stable isotope analysis, the researchers uncovered several microfossils of plants, fish scales, and fish muscle fibers. This is a find never seen in the human remains of Mediterranean people from this age.. Theres substantial archaeological evidence demonstrating that people in the Central Mediterranean caught and ate fish, but this is the first time we have direct evidence that humans consumed these resources, or used their teeth for de-scaling activities, which is very unique, University of York archaeologist Dr. Harry Robson said in a press statement.. Finding skeletal remains with both plant and fish microfossils gives researchers greater clues into how Adriatic and Mediterranean foragers lived, and the similarities between their diet and that of modern ...

ABSTRACT: Epilithic bacterial communities play a major role in biogeochemical cycles of rivers; however, distributional patterns and controls of epilithic communities remain unclear. The objective of the present study was to examine possible environmental factors that affect longitudinal distributional patterns of epilithic bacterial communities in 2 rivers (Yasu and Ado Rivers) draining the Lake Biwa basin, Japan. Phylogenetic analyses were conducted using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes and fluorescence in situ hybridization (FISH) with oligonucleotide probes targeted to small subunit rRNA. Non-metric multidimensional scaling and canonical correspondence analysis of the DGGE profile indicated that a clear shift in community composition occurred at the middle reach of the Yasu River. This shift was most closely related to variation in the nitrogen stable isotope ratio (δ15N) of epilithic materials (BIOENV analysis, ρw = 0.512), which is an indicator of the ...

The research reported in this manuscript was conducted by a National Academy of Sciences, NRC Post-Doctoral Fellow, and a fellow of the Scientist Committee of NATO, both of whom were located at WED. The research was also funded by the National Science Foundation, Environmental Biology. The research contributed to the WED project Extrapolating Anthropogenic Stress Effects: Individuals to Forests, Ecosystems, and Regions (INFER). One overarching objective of INFER was to develop the capabilities to scale ecosystem processes across gradients of space, time and biological complexity to inform predictions of consequences of anthropogenic stresses. The overall objective of this collaborative research was to use stable isotope signatures of nitrogen and carbon to provide a mechanistic understanding of the taxanomic variation in how a dominant (in terms of biomass) functional group of soil microbiota (higher fungi) assimilate and partition nitrogen and carbon across a large geographic range within the ...

The present work reports the first data set on particulate organic carbon (POC) and nitrogen (PON), and the highresolution modelling of their stable isotope variability in the Patagonian Cold Estuarine System (PCES), with focus on particulate organic matter (POM) origin and distribution in dependence on physical, chemical and biological parameters. POC, PON, stable carbon (δ13C) and nitrogen isotopes (δ15N), dissolved organic nitrogen, phaeopigments, diatom, dinoflagellate and heterotrophic bacteria (HB) abundance are reported for 17 stations in different waters masses in the southern end of the Argentine shelf in late summer 2012. Most parameters denote clear differences between Beagle-Magellan Water (BMW), Subantarctic ShelfWater (SSW) and Subantarctic Water (SAW). POC and PON decreased frommaxima in BMWto intermediate values in SSWandminima in SAW. There was a highly significant correlation among POC, PON and fluorescence indicators of diagenetic maturity of dissolved humic matter. This, ...

Solid state NMR:. Any researcher who needs solid state spectroscopy is able to request time on this spectrometer. There are two solid state NMR probes available, each triple resonance with fixed 1H, 13C, and 15N channels: Probe 1: E-free 3.2 mm probe (MAS up to 24 kHz) ; and Probe 2: CMP probe (MAS up to 15 kHz).e probes having fixed 1H, 13C, 15N channel.. Probe #1: E-free 3.2 mm probe (MAS up to 24kHz): This is a top-loading E-Free triple resonance Magic Angle Spinning probe for solid state NMR of biological samples. It has been optimized for 13C and/or 15N observation / decoupling and 1H high-power decoupling. A special coil configuration minimizes the electric field at the sample, and strongly reduces RF heating when dielectric samples are studied. Active volume that is required can be varied from 10 to 30µL using special inserts and 24 kHz maximum spinning speed. VT range -80o C to +80o C. MAS heat exchanger system BCU-II is available for VT below ambient. Triple resonance experiments are ...

Analysis of stable carbon and nitrogen isotopes in the bones of early humans from the Buran Kaya caves on the Crimean Peninsula, Russia-occupied Ukraine, and

Sequence specific resonance assignment constitutes an important step towards high-resolution structure determination of proteins by NMR and is aided by selective identification and assignment of amino acid types. The traditional approach to selective labeling yields only the chemical shifts of the particular amino acid being selected and does not help in establishing a link between adjacent residues along the polypeptide chain, which is important for sequential assignments. An alternative approach is the method of amino acid selective `unlabeling or reverse labeling, which involves selective unlabeling of specific amino acid types against a uniformly C-13/N-15 labeled background. Based on this method, we present a novel approach for sequential assignments in proteins. The method involves a new NMR experiment named, {(CO)-C-12 (i) -N-15 (i+1)}-filtered HSQC, which aids in linking the H-1(N)/N-15 resonances of the selectively unlabeled residue, i, and its C-terminal neighbor, i + 1, in ...

For example, carbonate apatite - a primary constituent of both skeletal bones and dentition in vertebrates - is incorporated into organisms through diet and water uptake. Some conservationists use the isotopic signatures recovered from this apatite to better decipher the life histories of contemporary species in expectation of aiding in their continued preservation. As a case in point, remains from the worlds largest cavefish (Milyeringa veritas) have been used by Australian conservationists to better examine and comprehend the environment and ecosystem inhabited by the fish. The cavefish resides in deep water columns that are rich in dissolved limestone. Due to relative densities and variable solubility, different depths in the water column are correlated to specific concentrations of dissolved materials. By examining the isotopic signatures of the cavefishs skeletal apatite, conservationists were able to discover the exact depth the fish occupies ...

This material is based upon work supported by the National Science Foundation under grant DEB#1545288, 10/1/2015-9/30/19 and DEB#1929393, 09/01/2019-08/31/2024. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.. ...

The main aim of this thesis is to show how scientific methods may be used to look at migration in prehistory on the basis of archaeological material. The individuals examined represent the period 4 000 BC to 1 000 AD and have their geographical origins in various parts of Sweden.. Ancient DNA analysis is employed in three cases. The first is an investigation of the genetic profiles of the two main cultural groups, which existed in Sweden during the Neolithic, the Funnel Beaker (TRB) and Pitted Ware (PWC) cultures. We can deduce from these genetic data that they were two separate populations, and can see that the TRB genetic profiles continue into the Bronze Age whereas the PWC profiles seem to disappear. In a second analysis based on the same material we explore the ability of adults to digest milk, i.e. lactose tolerance, a genetic trait found in high frequencies in northern Europe. We can see that the TRB population had a higher frequency of this allele than the PWC population. The last paper ...

This material is based upon work supported by the National Science Foundation under grant DEB#1545288, 10/1/2015-9/30/19 and DEB#1929393, 09/01/2019-08/31/2024. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.. ...

Documentary evidence and artistic representations have traditionally served as the primary sources of information about Byzantine diet. According to these sources, Byzantine diet was based on grain (primarily wheat and barley), oil, and wine, supplemented with legumes, dairy products, meat, and marine resources. Here, we synthesize and compare the results of stable isotope ratio analyses of eight Greek Byzantine populations (6th-15th centuries AD) from throughout Greece. The δ13C and δ15N values are tightly clustered, suggesting that all of these populations likely consumed a broadly similar diet. Both inland and coastal Byzantine populations consumed an essentially land-based C3 diet, significant amounts of animal protein, and possibly some C4 plants, while no evidence of a general dependence on low-δ15N legumes was observed. One interesting result observed in the isotopic data is the evidence for the consumption of marine protein at both coastal sites (a reasonable expectation given their ...

Stable isotopes are widely used to identify trophic interactions and to determine trophic positions of organisms in food webs. Comparative studies have provided general insights into the variation in isotopic composition between consumers and their diet (discrimination factors) in predator-prey and herbivore-plant relationships while other major components of food webs such as host-parasite interactions have been largely overlooked.

Tardani, D., Reich, M., Roulleau, E., Takahata, N., Sano, Y., Perez-Flores, P., Sanchez-Alfaro, P., Cembrano, J., and Arancibia, G., 2016: Geochimica Et Cosmochimica Acta, v. 184, p. 193-211.. Abstract:. There is a general agreement that fault-fracture meshes exert a primary control on fluid flow in both volcanic/magmatic and geothermal/hydrothermal systems. For example, in geothermal systems and epithermal gold deposits, optimally oriented faults and fractures play a key role in promoting fluid flow through high vertical permeability pathways. In the Southern Volcanic Zone (SVZ) of the Chilean Andes, both volcanism and hydrothermal activity are strongly controlled by the Liquine-Ofqui Fault System (LOFS), an intra-arc, strike-slip fault, and by the Arc-oblique Long-lived Basement Fault System (ALFS), a set of transpressive NW-striking faults. However, the role that principal and subsidiary fault systems exert on magma degassing, hydrothermal fluid flow and fluid compositions remains poorly ...

Reptile growth is influenced by many ecological processes that can cumulatively give rise to divergent somatic growth rates within spatially structured populations. As somatic growth variation can strongly influence a species population dynamics, identifying proximate drivers can be critical to the conservation and management of protected species. Kemps ridley sea turtles (Lepidochelys kempii) exhibit spatial variation in both diet composition and growth, but whether components of this variation are linked has not been evaluated. Through an integration of skeletochronological and stable isotope analyses of stranded turtle humerus bones we characterized regional variation in Kemps ridley diet composition and potential relationships with somatic growth rates. Turtles were divided among five regions within the United States Gulf of Mexico (GoM) and Atlantic Coast based on location of stranding, and humerus bones were sampled for stable carbon (δ13C) and nitrogen (δ15N) isotope ratios. These data were

Biomolecular NMR Assignments provides a forum for publishing sequence-specific resonance assignments for proteins and nucleic acids as Assignment Notes. Chemical shifts for NMR-active nuclei in macromolecules contain detailed ...

Barbers and salon owners were supportive, Ehleringer says. They would then let us go to the trash bin and pull out a handful or two of hair, which we then sort into identifiable clusters representing individuals. This sampling technique was blind, he adds, to the individuals age, gender, income, health status or any other factor, except for the isotope record. All together, they collected samples representing nearly 700 people.. The results showed variations in hair isotope ratios, both locally and nationally, but within a relatively narrow range. Within that variation, the researchers found, carbon isotope values correlated with the cost of living in the ZIP codes where the samples were collected. Previous studies provided the expected isotope values from the ends of the diet spectrum, from vegans to meat-prominent omnivores.. The samples collected from the Salt Lake Valley offered an opportunity to examine in greater detail the factors behind the isotope variation. Surprisingly, carbon ...

Breast cancer is the most common cancer in women worldwide. Despite the information provided by anatomopathological assessment and molecular markers (such as receptor expression ER, PR, HER2), breast cancer therapies and prognostics depend on the metabolic properties of tumor cells. However, metabolomics have not provided a robust and congruent biomarker yet, likely because individual metabolite contents are insufficient to encapsulate all of the alterations in metabolic fluxes. Here, we took advantage of natural 13 C and 15 N isotope abundance to show there are isotopic differences between healthy and cancer biopsy tissues or between healthy and malignant cultured cell lines. Isotope mass balance further suggests that these differences are mostly related to lipid metabolism, anaplerosis and urea cycle, three pathways known to be impacted in malignant cells. Our results demonstrate that the isotope signature is a good descriptor of metabolism since it integrates modifications in C partitioning and N