Systematics of 2H patterns in natural compounds and its importance for the elucidation of biosynthetic pathways

Schmidt, Hanns‐Ludwig; Werner, Roland A.; Eisenreich, Wolfgang

doi:10.1023/b:phyt.0000004185.92648.ae

Cited by 192 publications

(275 citation statements)

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“…The effect of salinity on hydrogen isotope fractionation seems to be a general feature recorded in alkenones, fatty acids, sterols, phytene, and diploptene produced by algal photoautotrophs (Heinzelmann et al, 2015;Schouten et al, 2006;Sachse and Sachs, 2008;Sachs and Schwab, 2011;Nelson and Sachs, 2014). Nicotinamide adenine dinucleotide phosphate (NADPH) is associated with large isotope fractionation values, larger than the fractionation between extracellular and intracellular water, but both are used as sources of H for synthesis of organic compounds (Schmidt et al, 2003). NADPH has been proposed to supply around 50 % of the H eventually used for lipid production in the bacterium Escherichia coli (Kazuki et al, 1980), and it is presumed to be roughly the same for photosynthetic algae (Zhang et al, 2009).…”

Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 99%

“…NADPH has been proposed to supply around 50 % of the H eventually used for lipid production in the bacterium Escherichia coli (Kazuki et al, 1980), and it is presumed to be roughly the same for photosynthetic algae (Zhang et al, 2009). The cell generates NADPH either photosynthetically or via the oxidative portion of the pentose phosphate pathway (OPP pathway) (Schmidt et al, 2003;Wamelink et al, 2008). NADPH derived via ferredoxin-NADP+ reductase (FNR) in photosystem 1 (photosynthetically derived) tends to be depleted by ∼ 600 ‰ in D when compared to intracellular water (Luo et al, 1991), whereas NADPH produced via the OPP pathway is also depleted compared to intracellular water, but much less than photosynthetically derived NADPH (Schmidt et al, 2003;Maloney et al, 2016).…”

Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 99%

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Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

et al. 2017

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Abstract. Over the last decade, hydrogen isotopes of longchain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δD C 37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high-and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

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Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 99%

Section: Potential Mechanisms For Salinity and Light Responsesmentioning

confidence: 99%

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

et al. 2017

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“…Isotopic labeling studies of fatty acid biosynthesis in vitro provide a rough accounting of the H sources for fatty acids (1,35,36). They indicate that the most important cellular H source is NAD(P)H, providing Ϸ50% of fatty acid H (Fig.…”

Section: Sources Of D/h Variability In Fatty Acidsmentioning

confidence: 99%

“…Thus, differences in fractionations between flavin-free pyridine nucleotide-dependent enzymes like FabG and FabI versus flavoproteins like FabK might provide a mechanism for lipid D/H variability. The former catalyze direct hydride (H Ϫ ) transfer from NAD(P)H to fatty acids (24,38,39), whereas in the latter H Ϫ is transferred via the flavin ring, which is susceptible to isotopic exchange with water (36,40,41). Differing fractionations between the enzyme types are therefore plausible.…”

Section: Sources Of D/h Variability In Fatty Acidsmentioning

confidence: 99%

Large D/H variations in bacterial lipids reflect central metabolic pathways

Zhang¹,

Gillespie

Sessions

2009

Proc. Natl. Acad. Sci. U.S.A.

202

268

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Large hydrogen-isotopic (D/H) fractionations between lipids and growth water have been observed in most organisms studied to date. These fractionations are generally attributed to isotope effects in the biosynthesis of lipids, and are frequently assumed to be approximately constant for the purpose of reconstructing climatic variables. Here, we report D/H fractionations between lipids and water in 4 cultured members of the phylum Proteobacteria, and show that they can vary by up to 500‰ in a single organism. The variation cannot be attributed to lipid biosynthesis as there is no significant change in these pathways between cultures, nor can it be attributed to changing substrate D/H ratios. More importantly, lipid/water D/H fractionations vary systematically with metabolism: chemoautotrophic growth (approximately ؊200 to ؊400‰), photoautotrophic growth (؊150 to ؊250‰), heterotrophic growth on sugars (0 to ؊150‰), and heterotrophic growth on TCA-cycle precursors and intermediates (؊50 to ؉200‰) all yield different fractionations. We hypothesize that the D/H ratios of lipids are controlled largely by those of NADPH used for biosynthesis, rather than by isotope effects within the lipid biosynthetic pathway itself. Our results suggest that different central metabolic pathways yield NADPH-and indirectly lipids-with characteristic isotopic compositions. If so, lipid ␦D values could become an important biogeochemical tool for linking lipids to energy metabolism, and would yield information that is highly complementary to that provided by 13 C about pathways of carbon fixation.fatty acids ͉ fractionation ͉ metabolism ͉ hydrogen isotopes T he hydrogen-isotopic composition ( 2 H/ 1 H or D/H ratio, commonly expressed as a ␦D value) of lipids is being explored by scientists with diverse interests, including the origins of natural products (1, 2), biogeochemical cycles (3), petroleum systems (4), and paleoclimate (5-7). Because the D/H ratios of lipids are generally conserved over Ϸ10 6 -year time scales (8), they are a potentially useful tracer of biogeochemical pathways and processes in the environment. Most research to date has focused on higher plants, in which environmental water is the sole source of external hydrogen and consequently provides primary control over the D/H ratio of biosynthesized lipids (9). Although ␦D values for plant lipids and environmental water are generally well correlated, they are also substantially offset from each other. The biochemical basis for this lipid/water fractionation is not well understood. It is generally assumed to arise from a combination of isotope effects during photosynthesis and the biosynthesis of lipids (9-12), and is often treated as approximately constant to reconstruct isotopic compositions of environmental water as a paleoclimate proxy.There is, however, mounting evidence that the net D/H fractionation between lipids and water can vary by up to 150‰ in plants, even in the same organism (12-16). Modest fractionations associated with fatty acid elongation and desaturation ...

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“…Geochemical and biochemical processes are conducive to isotope fractionation, which can be exploited for a wide variety of analytical approaches, e.g., to determine the biological and͞or geographic origin of organic material (for recent reviews, see refs. [2][3][4][5]. For example, the distribution of stable carbon isotopes in ''natural abundance'' chitin and lipids was shown to be modulated by dietary conditions in experiments with the American cockroach (Periplaneta americana) (6).…”

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confidence: 99%

Isotopolog perturbation techniques for metabolic networks: Metabolic recycling of nutritional glucose inDrosophila melanogaster

Eisenreich

Ettenhuber²,

Laupitz³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Drosophila melanogaster strain Oregon-R* was grown on standard medium supplemented with [U-13 C6]glucose. One to two days after hatching, flies were extracted with water. Glucose was isolated chromatographically from the extract and was analyzed by 13 C NMR spectroscopy. All 13 C signals of the isolated glucose were multiplets arising by 13 C 13 C coupling. Based on a comprehensive analysis of the coupling constants and heavy isotope shifts in glucose, the integrals of individual 13 C signal patterns afforded the concentrations of certain groups of 13 C isotopologs. These data were deconvoluted by a genetic algorithm affording the abundances of all single-labeled and of 15 multiply labeled isotopologs. Among the latter group, seven isotopologs were found at concentrations >0.1 mol % with [1,2-13 C2]glucose as the most prominent species. The multiply 13 Clabeled glucose isotopologs are caused by metabolic remodeling of the proffered glucose via a complex network of catabolic and anabolic processes involving glycolysis and͞or passage through the pentose phosphate, the Cori cycle and͞or the citrate cycle. The perturbation method described can be adapted to a wide variety of experimental systems and isotope-labeled precursors.stable isotope ͉ nuclear magnetic resonance ͉ genetic algorithm ͉ insect ͉ X group

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Systematics of 2H patterns in natural compounds and its importance for the elucidation of biosynthetic pathways

Cited by 192 publications

References 103 publications

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Large D/H variations in bacterial lipids reflect central metabolic pathways

Isotopolog perturbation techniques for metabolic networks: Metabolic recycling of nutritional glucose inDrosophila melanogaster

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Systematics of 2H patterns in natural compounds and its importance for the elucidation of biosynthetic pathways

Cited by 192 publications

References 103 publications

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by &lt;i&gt;Emiliania huxleyi&lt;/i&gt;

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by &lt;i&gt;Emiliania huxleyi&lt;/i&gt;

Large D/H variations in bacterial lipids reflect central metabolic pathways

Isotopolog perturbation techniques for metabolic networks: Metabolic recycling of nutritional glucose inDrosophila melanogaster

Contact Info

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Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>