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1.
Stable hydrogen and carbon isotopic compositions of individual n-alkanes were determined for various terrestrial plants (33 samples including 27 species) and aquatic plants (six species) in natural environments from Japan and Thailand. In C3 plants, n-alkanes extracted from angiosperms have a deltaD value of -152+/-26 per thousand (relative to Standard Mean Ocean Water [SMOW]) and delta13C value of -36.1+/-2.7 per thousand (relative to Peedde Belemnite [PDB]), and those from gymnosperms have a deltaD value of -149+/-16 per thousand and delta13C value of -31.6+/-1.7 per thousand. Angiosperms have n-alkanes depleted in 13C relative to gymnosperms. n-Alkanes from C4 plants have a deltaD value of -171+/-12 per thousand and delta13C value of -20.5+/-2.1 per thousand, being a little depleted in D and much enriched in 13C compared to C3 plants. n-Alkanes of CAM plants are a little depleted in D and vary widely in delta13C relative to those of C3 and C4 plants. In aquatic plants, n-alkanes from freshwater plants have a deltaD value of -187+/-16 per thousand and delta13C value of -25.3+/-1.9 per thousand, and those from seaweeds have a deltaD value of -155+/-34 per thousand and delta13C value of -22.8+/-1.0 per thousand. All n-alkanes from various plant classes are more depleted in D and 13C relative to environmental water and bulk tissue, respectively. In addition, the hydrogen and carbon isotopic fractionations during n-alkane synthesis are distinctive for these various plant classes. While C3 plants have smaller isotopic fractionations in both D and 13C, seaweed has larger isotopic fractionations. 相似文献
2.
Effect of lipid removal on carbon and nitrogen stable isotope ratios in crustacean tissues 总被引:1,自引:0,他引:1
Nathalie Bodin François Le Loc'h Christian Hily 《Journal of experimental marine biology and ecology》2007,341(2):168-175
The analysis of tissue's naturally occurring stable carbon and nitrogen isotope ratios is a useful tool to delineate trophic relationships. However, the interpretation of δ13C and δ15N is complicated by the influence of multiple factors such as the tissue-specific lipid content. The aim of this work was to evaluate the effects of lipid extraction on δ13C and δ15N compositions in muscle, hepatopancreas and gonads of a marine decapod crustacean, the spider crab Maja brachydactyla. Samples were analyzed for stable isotopes before and after lipid removal, using a derived Soxhlet extraction method. Differences in δ13C and δ15N were measured among tissues before and after treatment. Lipid extraction of muscle did not have a significant effect on either δ13C or δ15N. By contrast, ecologically significant shifts for both carbon and nitrogen stable isotopes ratios (+ 2.9 ± 0.8‰ for δ13C, and + 1.2 ± 0.7‰ for δ15N) were noticed in the hepatopancreas. In regard to gonads, lipid extraction led to a shift only on δ13C (+ 1.3 ± 0.3‰). Finally, the derived Soxhlet extraction method removed the lipid influence for δ13C, and had an effect on δ15N composition for lipid-rich samples. We recommend this treatment for carbon stable isotope studies on decapod crustacean lipid-rich tissues. 相似文献
3.
We determined hydrogen, carbon and nitrogen isotopic compositions of chlorophylls a and b isolated from leaves of five C3 higher plant species (Benthamidia japonica, Prunus japonica, Acer carpinifolium, Acer argutum and Querus mongloica), and hydrogen and carbon isotopic compositions of phytol and chlorophyllides in the chlorophylls to understand isotopic fractionations associated with chlorophyll biosynthesis in these species. Chlorophylls are depleted in D relative to ambient water by approximately 189 per thousand and enriched in (13)C relative to bulk tissue by approximately 1.6 per thousand. These data can be explained by the contribution of isotopic fractionations during phytol and chlorophyllide biosyntheses. Phytol is more depleted in both D (by approximately 308 per thousand) and (13)C (by approximately 4.3 per thousand), while chlorophyllides are less depleted in D (by approximately 44 per thousand) and enriched in (13)C (by approximately 4.8 per thousand). Such inhomogeneous distribution of isotopes in chlorophylls suggests that (1) the phytol in chlorophylls reflects strong D- and (13)C-depletions due to the isotopic fractionations during the methylerythritol phosphate pathway followed by hydrogenation, and (2) the chlorophyllides reflect D- and (13)C-enrichments in tricarboxylic acid cycle. On the other hand, chlorophylls are slightly ( approximately 1.2 per thousand) depleted in (15)N relative to the bulk tissue, indicating that net isotopic fractionation of nitrogen during chlorophyll biosynthesis is small compared with those of hydrogen and carbon. 相似文献
4.
Administration of (13)C labeled acetates ([1-(13)C], [2-(13)C] and [1,2-(13)C(2)] to Lasiodiplodia theobromae showed the tetraketide origins of both theobroxide, a potato-tuber inducing substance [1, (1S, 2R, 5S, 6R)-3-methyl-7-oxa-bicyclo[4.1.0]hept-3-en-2,5-diol]) and its carbonyldioxy derivative [2, (1S, 4R, 5S, 6R)-7,9-dioxa-3-methyl-8-oxobicyclo [4.3.0]-2-nonene-4,5-diol]. The incorporation of acetate-derived hydrogen into 1 and 2 was studied using [2-(2)H(3), 2-(13)C]acetate. Three and one deuterium atoms were incorporated at one methyl and epoxy carbons, respectively. The observed loss of deuterium atoms from the methyl group suggests a considerable amount of exchange from the methyl group of [2-(2)H(3), 2-(13)C]acetate during biosynthesis of 1 and 2. Incorporation of [1-(13)C]- and [1,2-(13)C(2)]acetates indicates the carbonyl carbon of the carbonyldioxy derivative is derived from the carboxy carbon of the precursor. 相似文献
5.
Tobias Tamelander Janne E. Søreide Haakon Hop 《Journal of experimental marine biology and ecology》2006,333(2):231-240
Fractionation of δ13C and δ15N between food, consumer, and faecal pellets was studied in the Arctic marine copepod Calanus glacialis Jaschnov, fed with isotopically distinct algal monocultures. Temporal variations in δ13C and δ15N of copepods that were fed ice algae and phytoplankton followed those of a control group consisting of starved animals. There were no significant trends in the δ13C and δ15N values of copepods that were starved for 42 days, suggesting that the isotopic composition of non-lipid body tissues is unaffected by the metabolic processes during prolonged periods of starvation. The stable isotopic composition of starved copepods therefore seems to reflect food consumed during the previous period of feeding and growth. Faecal pellets produced by feeding copepods were depleted in 13C and 15N by 6.3-11.2‰ and 0.7-9.1‰, respectively, relative to the food ingested. These results indicate that faecal pellet production is an important pathway for the trophic fractionation of δ13C, whereas other fractionation pathways, such as excretion of ammonia, may be relatively more important for δ15N. The strong depletion of 13C in faecal pellets compared to the food suggests that grazing by herbivorous copepods on primary production adds to the variability of δ13C in marine particulate organic matter. 相似文献
6.
Leaves of 26 grass, herb, shrub and tree species were collected from mesotrophic grasslands to assess natural variability in bulk, fatty acid and monosaccharide δ13C values under different grazing management (cattle- or deer-grazed) on three sample dates (May, July and October) such that interspecific and spatiotemporal variations in whole leaf tissues and compound-specific δ13C values could be determined. The total mean leaf bulk δ13C value for plants was −28.9‰ with a range of values spanning 7.5‰. Significant interspecific variation between bulk leaf δ13C values was only determined in October (P = <0.001) when δ13C values of the leaf tissues from both sites was on average 1.5‰ depleted compared to during July and May. Samples from May were significantly different between fields (P = 0.03) indicating an effect from deer- or cattle-grazing in young leaves. The average individual monosaccharide δ13C value was 0.8‰ higher compared with whole leaf tissues. Monosaccharides were the most abundant components of leaf biomass, i.e. arabinose, xylose, mannose, galactose and glucose, and therefore, fluctuations in their individual δ13C values had a major influence on bulk δ13C values. An average depletion of ca. 1‰ in the bulk δ13C values of leaves from the deer-grazed field compared to the cattle-grazed field could be explained by a general depletion of 1.1‰ in glucose δ13C values, as glucose constituted >50% total leaf monosaccharides. In October, δ13C values of all monosaccharides varied between species, with significant variation in δ13C values of mannose and glucose in July, and mannose in May. This provided an explanation for the noted variability in the tissue bulk δ13C values observed in October 1999. The fatty acids C16:0, C18:2 and C18:3 were highly abundant in all plant species. Fatty acid δ13C values were lower than those of bulk leaf tissues; average values of −37.4‰ (C16:0), −37.0‰ (C18:2) and −36.5‰ (C18:3) were determined. There was significant interspecific variation in the δ13C values of all individual fatty acids during October and July, but only for C18:2 in May (P = <0.05). This indicated that seasonal trends observed in the δ13C values of individual fatty acids were inherited from the isotopic composition of primary photosynthate. However, although wide diversity in δ13C values of grassland plants ascribed to grazing management, interspecific and spatiotemporal influences was revealed, significant trends (P = <0.0001) for fatty acid and monosaccharide δ13C values: δ13C16:0 < δ13C18:2 < δ13C18:3 and δ13Carabinose > δ13Cxylose > δ13Cglucose > δ13Cgalactose, respectively, previously described, appear consistent across a wide range of species at different times of the year in fields under different grazing regimes. 相似文献
7.
CP/MAS 13C NMR spectroscopy was used in combination with spectral fitting to examine the surface structure of hydrated cellulose I fibrils from Halocynthia and Gluconoacetobacter xylinus. To increase the spectral intensities and minimize signal overlap, G. xylinus celluloses site-specifically enriched in 13C either on C4 or on both C1 and C6 were examined. The experimental data showed multiple C4 and C6 signals for the water accessible fibril surfaces in the highly crystalline celluloses. These signal multiplicities were attributed to structural features in the surface layers induced by the fibril interior, and could not be extracted by spectral fitting in celluloses with a lower degree of crystallinity such as cellulose from cotton. 相似文献
8.
Yoshikazu Sampei Eiji Matsumoto Takao Tokuoka Osamu Abe 《Palaeogeography, Palaeoclimatology, Palaeoecology》2005,224(4):352-366
Based on the relationship between salinity and δ18O and δ13C of modern shells in the Lake Nakaumi-Shinji lagoon system (southwestern Japan), where the salinity changes regularly from ca. 1 PSU to 34 PSU, a paleosalinity record for Nakaumi Lagoon during the Holocene has been derived from bulk mollusk shell δ18O and δ13C data. The robust relationships between the salinity and modern shell δ18Oar and δ13Car (aragonite) were used to calibrate the paleosalinity reconstruction. The salinity relationships are expressed by the regressions:
Salinity (PSU)=3.86 δ18Oar(‰ VPDB)+33.9 (n=18, r=0.978) 相似文献
9.
Root cultures of Tagetes patula L. cv. Carmen were grown with a mixture of unlabeled glucose and [U-(13)C(6)]glucose or [1-(13)C(1)]glucose as carbon source. Isoeuparin and (-)-4-hydroxytremetone were isolated by solvent extraction of the cultured tissue, purified by chromatography and analysed by (1)H and (13)C NMR spectroscopy. Amino acids obtained by hydrolysis of protein from the same experiments were used for the reconstruction of the labelling patterns in central metabolic intermediates. These labelling patterns were used for the prediction of isotopolog compositions in the benzofuranone derivatives via different hypothetical pathways. Comparison with the experimentally observed isotopolog distributions showed that the benzenoid ring and the acetoxy group are exclusively or predominantly (>98%) derived from phenylalanine and not from acetyl-CoA via a polyketide-type biosynthesis. The isopropylidene side chain and two carbon atoms of the furan and dihydrofuran moiety, respectively, originate from an isoprenoid building block obtained exclusively or predominantly (>98%) via the deoxyxylulose phosphate pathway. The exomethylene atom of the isopropylidene side chain is biosynthetically equivalent to the (Z)-methyl group of dimethylallyl diphosphate. The data indicate that isoeuparin and (-)-4-hydroxytremetone are assembled from 4-hydroxyacetophenone and dimethylallyl diphosphate via prenyl-substituted 4-hydroxyacetophenone and dihydrobenzofurans as intermediates. 相似文献
10.
Background and Aims The green orchid Goodyera repens has been shown to transfer carbon to its mycorrhizal partner, and this flux may therefore be affected by light availability. This study aimed to test whether the C and N exchange between plant and fungus is dependent on light availability, and in addition addressed the question of whether flowering and/or fruiting individuals of G. repens compensate for changes in leaf chlorophyll concentration with changes in C and N flows from fungus to plant.Methods The natural abundances of stable isotopes of plant C and N were used to infer changes in fluxes between orchid and fungus across natural gradients of irradiance at five sites. Mycorrhizal fungi in the roots of G. repens were identified by molecular analyses. Chlorophyll concentrations in the leaves of the orchid and of reference plants were measured directly in the field.Key Results Leaf δ13C values of G. repens responded to changes in light availability in a similar manner to autotrophic reference plants, and different mycorrhizal fungal associations also did not affect the isotope abundance patterns of the orchid. Flowering/fruiting individuals had lower leaf total N and chlorophyll concentrations, which is most probably explained by N investments to form flowers, seeds and shoot.Conclusions The results indicate that mycorrhizal physiology is relatively fixed in G. repens, and changes in the amount and direction of C flow between plant and fungus were not observed to depend on light availability. The orchid may instead react to low-light sites through increased clonal growth. The orchid does not compensate for low leaf total N and chlorophyll concentrations by using a 13C- and 15N-enriched fungal source. 相似文献
11.
Carbon-13 nuclear magnetic resonance spectroscopy in combination with the infusion of 13C-labeled precursors is a unique approach to study in vivo brain energy metabolism. Incorporating the maximum information available from in vivo localized 13C spectra is of importance to get broader knowledge on cerebral metabolic pathways. Metabolic rates can be quantitatively determined from the rate of 13C incorporation into amino acid neurotransmitters such as glutamate and glutamine using suitable mathematical models. The time course of multiplets arising from 13C-13C coupling between adjacent carbon atoms was expected to provide additional information for metabolic modeling leading to potential improvements in the estimation of metabolic parameters.The aim of the present study was to extend two-compartment neuronal/glial modeling to include dynamics of 13C isotopomers available from fine structure multiplets in 13C spectra of glutamate and glutamine measured in vivo in rats brain at 14.1 T, termed bonded cumomer approach. Incorporating the labeling time courses of 13C multiplets of glutamate and glutamine resulted in elevated precision of the estimated fluxes in rat brain as well as reduced correlations between them. 相似文献
12.
Constituents of Lepidium meyenii 'maca'. 总被引:4,自引:0,他引:4
The tubers of Lepidium meyenii contain the benzylated derivative of 1,2-dihydro-N-hydroxypyridine, named macaridine, together with the benzylated alkamides (macamides), N-benzyl-5-oxo-6E,8E-octadecadienamide and N-benzylhexadecanamide, as well as the acyclic keto acid, 5-oxo-6E,8E-octadecadienoic acid. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR spectroscopic analyses, including 1H-1H COSY, 1H-13C HMQC, 1H-13C HMBC and 1H-1H NOESY experiments, as well as from 1H-15N NMR HMBC correlations for macaridine and N-benzylhexadecanamide. 相似文献
13.
Drzewiecka D Toukach PV Arbatsky NP Zych K Shashkov AS Knirel YA Sidorczyk Z 《Carbohydrate research》2002,337(17):1535-1540
The O-specific polysaccharide of the lipopolysaccharide of Proteus penneri strain 103 was studied using 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, H-detected 1H,(13)C HMQC, 1H, 31P HMQC, and HMBC experiments. It was found that the polysaccharide is built up of oligosaccharide-ribitol phosphate repeating units and thus resembles ribitol teichoic acids of Gram-positive bacteria. The following structure of the polysaccharide was established:where Etn and Rib-ol are ethanolamine and ribitol, respectively. This structure is unique among the known structures of Proteus O-antigens and, therefore, we propose classification of the strain studied into a new Proteus serogroup, O73. The molecular basis for cross-reactivity between O-antiserum against P. penneri 103 and O-antigens of P. mirabilis O33 and D52 is discussed. 相似文献
14.
13C metabolism analysis of a microbial community is often hindered by the time-consuming and complicated separation procedure for a single species. However, a “reporter protein,” produced uniquely by one cell type, retains 13C fingerprint information in microbial consortia. This study describes the use of photosystem I (PSI), a multi-subunit protein complex universally found in oxygenic phototrophs, as a reliable reporter protein to probe microalgal metabolism (i.e., cyanobacterium Synechocystis sp. PCC 6803) in a mixed culture with heterotrophic bacteria (i.e., Escherichia coli). We demonstrate that efficient purification of PSI and subsequent 13C-based amino acid analyses may decipher photomixotrophic metabolism of Synechocystis 6803 in the coculture. This study also indicates that a supplement of NaHCO3 at high concentration could significantly improve the robustness of cyanobacterial growth against bacterial contamination. 相似文献
15.
Compound-specific carbon and hydrogen isotopic compositions of lipid biomolecules (n-alkanes, n-alkanoic acids, n-alkanols, sesquiterpenes, diterpenes, phytol, diterpenols and β-sitosterol), extracted from Cryptomeria japonica leaves, were determined in order to understand isotopic fractionations occurring during lipid biosynthesis in this species. All lipid biomolecules were depleted in both 13C and D relative to bulk tissue and ambient water, respectively. n-Alkyl lipids associated with the acetogenic pathway were depleted in 13C relative to bulk tissue by 2.4-9.9‰ and depleted in D relative to ambient water by 91-152‰. C15- and C30-isoprenoid lipids (sesquiterpenes, squalene and β-sitosterol) associated with the mevalonic-acid pathway are depleted in 13C relative to bulk tissue by 1.7-3.1‰ and depleted in D relative to ambient water by 212-238‰. C20-isoprenoid lipids (phytol and diterpenoids) associated with the non-mevalonic-acid pathway were depleted in 13C relative to bulk tissue by 4.6-5.9‰ and depleted in D relative to ambient water by 238-303‰. Phytol was significantly depleted in D by amounts up to 65‰ relative to other C20 isoprenoid lipids. The acetogenic, mevalonic-acid and non-mevalonic-acid pathways were clearly discriminated using a cross-plot between the carbon and hydrogen isotopic fractionations. 相似文献
16.
The incorporation of [1-13C] labelled glucose into hodgsonox, a sesquiterpene epoxide with a unique, doubly allylic ether functionality has been studied in axenic cultures of the liverwort Lepidolaena hodgsoniae. Quantitative 13C NMR spectroscopic analysis showed that the isoprene units are derived exclusively from the methylerythritol phosphate pathway. 相似文献
17.
Here we describe the fine root distribution of trees and grasses relative to soil nitrogen and water profiles. The primary objective is to improve our understanding of edaphic processes influencing the relative abundance of trees and grasses in savanna systems. We do this at both a mesic (737 mm MAP) site on sandy-loam soils and at an arid (547 mm MAP) site on clay rich soils in the Kruger National Park in South Africa. The proportion of tree and grass fine roots at each soil depth were estimated using the δ13C values of fine roots and the δ13C end members of the fine roots of the dominant trees and grasses at our study sites. Changes in soil nitrogen concentrations with depth were indexed using total soil nitrogen concentrations and soil δ15N values. Soil water content was measured at different depths using capacitance probes. We show that most tree and grass roots are located in the upper layers of the soil and that both tree and grass roots are present at the bottom of the profile. We demonstrate that root density is positively related to the distribution of soil nitrogen and negatively related to soil moisture. We attribute the negative correlation with soil moisture to evaporation from the soil surface and uptake by roots. Our data is a snapshot of a dynamic process, here the picture it provides is potentially misleading. To understand whether roots in this system are primarily foraging for water or for nitrogen future studies need to include a dynamic component. 相似文献
18.
The kavalactone, 11-methoxy-5,6-dihydroyangonin, and eight previously reported analogs along with four other aromatic compounds were isolated from the root extracts of Piper methysticum (Kava Kava). Their structural elucidations were made by 1H and 13C NMR spectroscopic assignments using COSY, HMBC and HMQC experiments. 相似文献
19.
Gaidamauskas E Norkus E Vaiciūniene J Crans DC Vuorinen T Jaciauskiene J Baltrūnas G 《Carbohydrate research》2005,340(8):1553-1556
Deprotonation of D-mannitol was studied in aqueous basic solutions by means of potentiometry and (13)C NMR spectroscopy. Two-step dissociation in the pH range from 12 to 13.8 was shown, and successive dissociation constants K(a1) and K(a2) were determined. In a solution with ionic strength I = 1.0 M (NaOH + NaNO(3)) pK(a1) = 13.1 +/- 0.1 and pK(a2) = 13.8 +/- 0.2. With increasing ionic strength from 0.75 to 3.0 M, both pK(a1) and pK(a2) values decrease. Deprotonation-induced chemical shifts in pH-variable (13)C NMR spectra show that the OH-groups next to internal carbon atoms C-3 and C-4 dissociate to a greater extent compared to OH-groups next to external carbon atoms C-1 and C-6. 相似文献
20.
The hydroxyl group stereochemistry of complexation of sodium vanadate(V) with Me alpha-Manp, Me alpha- and beta-Galp and selected O-methyl derivatives in D(2)O was determined by 51V, 1D and 2D 13C NMR spectroscopy at pD 7.8. The 51V approach served to show the extent of complexation and the minimum number of esters formed. That of Me alpha-Manp gave rise mainly to a 51V signal at delta -515, identical with that of its 4,6-di-O-methyl derivative, which had only a 2,3-cis-diol exposed. The 13C NMR spectra contained much weaker signals of the complexes, but both glycosides showed strong C-2 and C-3 alpha-shifts of +17.3 and +10.8 ppm, respectively. As expected, Me 2,3-Me(2)-alpha-Manp, which contains a 4,6-diol, did not complex. Me Galp anomers and their derivatives showed more diversity in the structure of its oxyvanadium derivatives. Me alpha-Galp, with its 3,4-cis-diol, complexed to give rise to 51V signals at delta -495 (9%), -508 (10%), and -534 (4%). These shifts and proportions were maintained with Me beta-Galp and Me 6Me-alpha-Galp. 51V NMR spectroscopy showed that Me 3Me-beta-Galp, with its possibly available 4,6-diol, did not complex. Similarly, Me alpha-Galp+vanadate gave a 13C DEPT spectrum that did not contain an inverted signal at delta >71.4, as would be expected of a C-6 resonance suffering a strong downfield alpha-shift. Me 2,6-Me(2)-alpha-Galp, with a 3,4-cis-diol group, gave rise to two 51V signals of complexes at delta -492 (9%) and -508 (9%), showing more than one structure of oxyvanadium derivatives. 相似文献