Elucidation of the Structure of Lignin-Carbohydrate Complexes in Ginkgo CW-DHP by 13C-2H Dual Isotope Tracer

To elucidate the chemical linkages between lignin and carbohydrates in ginkgo cell walls, 13C-2H-enriched cell wall-dehydrogenation polymers (CW-DHP) were selectively prepared with cambial tissue from Ginkgo biloba L. by feeding D-glucose-[6-2H2], coniferin-[α-13C], and phenylalanine ammonia-lyase (PAL) inhibitor. The abundant detection of 13C and 2H confirmed that D-glucose-[6-2H2] and coniferin-[α-13C] were involved in the normal metabolism of ginkgo cambial cells that had been effectively labelled with dual isotopes. In the ginkgo CW-DHP, ketal and ether linkages were formed between the C-α of lignin side chains and carbohydrates, as revealed by solid state CP/MAS 13C-NMR differential spectroscopy. Furthermore, the DMSO/TBAH ionic liquids system was used to fractionate the ball-milled CW-DHP into three lignin-carbohydrate complex (LCC) fractions: glucan–lignin complex (GL), glucomannan–lignin complex (GML), and xylan–lignin complex (XL). The XRD determination indicated that the cellulose type I of the GL was converted into cellulose type II during the separation process. The molecular weight was in the order of Ac-GL > Ac-GML > XL. The 13C-NMR and 1H-NMR differential spectroscopy of 13C-2H-enriched GL fraction indicated that lignin was linked with cellulose C-6 by benzyl ether linkages. It was also found that there were benzyl ether linkages between the lignin side chain C-α and glucomannan C-6 in the 13C-2H-enriched GML fraction. The formation of ketal linkages between the C-α of lignin and xylan was confirmed in the 13C-2H-enriched XL fraction.

Download Full-text

True ileal digestibility of legumes determined by dual-isotope tracer method in Indian adults

American Journal of Clinical Nutrition ◽

10.1093/ajcn/nqz159 ◽

2019 ◽

Vol 110 (4) ◽

pp. 873-882 ◽

Cited By ~ 7

Author(s):

Sindhu Kashyap ◽

Aneesia Varkey ◽

Nirupama Shivakumar ◽

Sarita Devi ◽

Rajashekar Reddy B H ◽

...

Keyword(s):

Mung Bean ◽

Deuterium Oxide ◽

Protein Digestibility ◽

Plant Protein ◽

Tracer Technique ◽

Feeding Method ◽

Dual Isotope ◽

Ileal Digestibility ◽

Isotope Tracer ◽

Plant Protein Sources

ABSTRACTBackgroundGood-quality plant protein sources are important for protein adequacy in a balanced diet. Legumes are known to be a source of good quality plant protein, but the true ileal digestibility of indispensable amino acids (IAAs) of commonly consumed legumes is not known in humans.ObjectivesIn this study we measured the true ileal IAA digestibility of 2H-intrinsically labeled chickpea, yellow pea, and mung bean (hulled and dehulled) protein, using the dual-isotope tracer technique referenced to a standard protein ([U-13C] spirulina). The study also aimed to validate the use of [U-13C] spirulina as a reference protein in this method.Methods2H-intrinsically labeled legumes, obtained by watering plants with deuterium oxide (2H2O), were administered in a plateau feeding method to healthy Indian adults to measure their true ileal IAA digestibility with the dual-isotope tracer technique, using [U-13C] spirulina protein or a 13C-algal IAA mixture as the standard.ResultThe true ileal IAA digestibilities (mean ± SD) of chickpea, yellow pea, and mung bean were 74.6 ± 0.8%, 71.6 ± 1.3%, and 63.2 ± 1.5%, respectively. The true mean ileal IAA digestibility of mung bean when referenced to [U-13C] spirulina protein or a 13C-algal IAA mixture did not differ significantly (63.2 ± 1.5% versus 64.0 ± 2.4%, P > 0.05). The true ileal IAA digestibility of mung bean improved to 70.9 ± 2.1% after dehulling.ConclusionsThe true mean ileal IAA digestibility of legumes in healthy Indian adults was lower than expected. Traditional processing techniques such as dehulling improve protein digestibility by about 8%. This study was registered in the Clinical Trials Registry of India (CTRI): CTRI/2017/11/010468 (http://ctri.nic.in, accessed on 28/03/2019).

Download Full-text

Ozonation of a lignin-carbohydrate complex model compound of the benzyl ether type

Journal of Wood Science ◽

10.1007/bf00776460 ◽

2000 ◽

Vol 46 (3) ◽

pp. 263-265 ◽

Cited By ~ 5

Author(s):

Olov Karlsson ◽

Tsutomu Ikeda ◽

Takao Kishimoto ◽

Kengo Magara ◽

Yuji Matsumoto ◽

...

Keyword(s):

Model Compound ◽

Complex Model ◽

Benzyl Ether ◽

Carbohydrate Complex

Download Full-text

Attomole Detection of3H in Biological Samples Using Accelerator Mass Spectrometry: Application in Low-Dose, Dual-Isotope Tracer Studies in Conjunction with14C Accelerator Mass Spectrometry

Chemical Research in Toxicology ◽

10.1021/tx9801458 ◽

1998 ◽

Vol 11 (10) ◽

pp. 1217-1222 ◽

Cited By ~ 30

Author(s):

Karen H. Dingley ◽

Mark L. Roberts ◽

Carol A. Velsko ◽

Kenneth W. Turteltaub

Keyword(s):

Mass Spectrometry ◽

Accelerator Mass Spectrometry ◽

Biological Samples ◽

Low Dose ◽

Tracer Studies ◽

Dual Isotope ◽

Isotope Tracer ◽

Mass Spectrometry Application

Download Full-text

Re-evaluating the Role of His-143 in the Mechanism of Type I Dehydroquinase fromEscherichia coliUsing Two-dimensional1H,13C NMR

Journal of Biological Chemistry ◽

10.1074/jbc.273.16.9602 ◽

1998 ◽

Vol 273 (16) ◽

pp. 9602-9607 ◽

Cited By ~ 10

Author(s):

Andrew P. Leech ◽

Ruth Boetzel ◽

Colin McDonald ◽

Annette K. Shrive ◽

Geoffrey R. Moore ◽

...

Keyword(s):

13C Nmr ◽

Type I

Download Full-text

Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults

American Journal of Clinical Nutrition ◽

10.1093/ajcn/nqy178 ◽

2018 ◽

Vol 108 (5) ◽

pp. 980-987 ◽

Cited By ~ 19

Author(s):

Sindhu Kashyap ◽

Nirupama Shivakumar ◽

Aneesia Varkey ◽

Rajendran Duraisamy ◽

Tinku Thomas ◽

...

Keyword(s):

Amino Acid ◽

Tracer Method ◽

Dual Isotope ◽

Ileal Digestibility ◽

Egg White Protein ◽

Meat Protein ◽

Isotope Tracer ◽

Hen’S Egg ◽

The Mean ◽

Cooked Meat

ABSTRACTBackgroundProtein quality assessment through the Digestible Indispensable Amino Acid Score requires accurate measurements of true ileal protein and amino acid digestibility, for which a dual isotope technique was recently developed. However, the ileal digestibility of indispensable amino acids (IAA) in humans from high-quality proteins is not well known.ObjectiveThe aim of this study was to intrinsically label hen's egg and meat protein by the use of uniformly 2H-labeled amino acids, and to measure their true ileal indispensable amino acid (IAA) digestibility via the dual isotope method in humans.Design2H-labeled lyophilized boiled egg white protein, whole boiled egg, and cooked meat were obtained from layer hens (BV-300) administered a uniformly 2H-labeled amino acid mix orally for 35 d with their daily feed. The ileal IAA digestibility of these proteins was determined with reference to digestibility of previously characterized [U-13C]spirulina in a dual tracer method in healthy Indian subjects whose intestinal health was measured by the plasma kynurenine-to-tryptophan (KT) ratio.ResultsAll subjects had normal KT ratios. The mean ± SD true ileal IAA digestibility of 2H-labeled egg white protein, whole boiled egg, and cooked meat was 86.3% ± 4.6%, 89.4% ± 4.5%, and 92.0% ± 2.8%, respectively. Leucine digestibility correlated with the KT ratio (r = −0.772; P = 0.009).ConclusionsUniformly 2H-labeled hen's egg and meat protein can be used to measure ileal IAA digestibility by the dual isotope tracer approach in humans. The mean IAA digestibility values for these high-quality proteins in the healthy Indians studied were similar to values obtained in earlier human and animal experiments. Leucine digestibility in these meal matrices correlated with the KT ratio, but this aspect needs further evaluation. This trial was registered at the Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.

Download Full-text

Accumulation of Microcystin (LR, RR and YR) in Three Freshwater Bivalves in Microcystis aeruginosa Bloom Using Dual Isotope Tracer

Marine Drugs ◽

10.3390/md15070226 ◽

2017 ◽

Vol 15 (7) ◽

pp. 226 ◽

Cited By ~ 11

Author(s):

Min-Seob Kim ◽

Yeon-Jung Lee ◽

Sun-Yong Ha ◽

Baik-Ho Kim ◽

Soon-Jin Hwang ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Dual Isotope ◽

Isotope Tracer ◽

Freshwater Bivalves

Download Full-text

Studies of the Metabolism of Asialotransferrins: the in Vivo Behavior of Baboon and Rhesus Asialotransferrins

Canadian Journal of Biochemistry ◽

10.1139/o75-171 ◽

1975 ◽

Vol 53 (12) ◽

pp. 1255-1261 ◽

Cited By ~ 5

Author(s):

E. Regoeczi ◽

M. W. C. Hatton ◽

K.-L. Wong

Keyword(s):

Hepatic Uptake ◽

Average Increase ◽

Tracer Technique ◽

Short Term ◽

Dual Isotope ◽

Isotope Tracer ◽

Catabolic Rate ◽

Nonprimate Mammal ◽

Reduced Data

The catabolism and distribution of rhesus and baboon asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual isotope tracer technique. Also a similar study with the baboon proteins in a baboon is reported.The metabolic data obtained in rabbits with both rhesus and baboon transferrins was close to the values established in a previous study for rabbit transferrin. Desialylation resulted in an average increase in the fractional catabolic rate of rhesus transferrin by 22.7%. This change is similar to that found earlier with asialotransferrins from several nonprimate mammals which are thought not to interact with the hepatic asialoglycoprotein receptor.Two kinetically distinct fractions were identified in baboon asialotransferrin. One of these, amounting to approximately one-third of the protein, was eliminated from the circulation very rapidly. The remaining two-thirds constituted a slowly catabolized fraction which behaved in vivo similarly to rhesus asialotransferrin. Unlike the rapidly cleared fraction, elimination of the slowly catabolized fraction in baboon asialotransferrin is probably not mediated by the hepatic asialoglycoprotein receptor. An amount comparable to the rapidly eliminated fraction in baboon asialotransferrin was recovered with the liver of rats in short-term experiments. In rats which were preinjected with chicken acid α1-glycoprotein the hepatic uptake of baboon asialotransferrin was markedly reduced. Data obtained in the baboon agreed with the findings in rabbits, although transferrin turnover was slower in the baboon.From its behavior in vivo as an asialoglycoprotein, baboon transferrin shows greater resemblance to human transferrin than rhesus transferrin. This conclusion is supported by carbohydrate analyses which show an intermediate position for baboon transferrin between man and a nonprimate mammal (rabbit), and a similarity between rhesus and rabbit transferrins.

Download Full-text

Coordinating Postanthesis Carbon and Nitrogen Metabolism of Hybrid Rice through Different Irrigation and Nitrogen Regimes

Agronomy ◽

10.3390/agronomy10081187 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1187

Author(s):

Yongjian Sun ◽

Yuanyuan Sun ◽

Fengjun Yan ◽

Yue Li ◽

Yunxia Wu ◽

...

Keyword(s):

Hybrid Rice ◽

Flag Leaf ◽

N Fertilization ◽

Utilization Efficiency ◽

Dual Isotope ◽

Carbon And Nitrogen ◽

Isotope Tracer ◽

Metabolism Enzymes ◽

N Metabolism ◽

Relationship Of

We sought to explore the role of postanthesis carbon and nitrogen (C-N) metabolism of hybrid rice in increasing yield and nitrogen utilization efficiency (NUE). We used the 13C and 15N dual-isotope tracer method and physiological/biochemical analysis and established different irrigation and nitrogen fertilization (W-N) regimes to investigate the relationship of C-N metabolism characteristics, yield, and NUE. The results showed that W-N regimes had significant effects on postanthesis absorption and translocation of N and photosynthate, yield and NUE. Aerobic irrigation combined with the N fertilization regime 30% base, 30% tillering, 40% booting was the best W-N coupling regime for rice yield and NUE increase. The regime enhanced flag leaf photosynthesis rate and the activities of ribulose 1,5-diphosphate carboxylase/oxygenase (RuBPCase), glutamine synthetase (GS), and other key enzymes of C-N metabolism, and improved the total accumulations of photoassimilates (0.97–21.57 mg 13C plant−1) and N (1.55–23.36 mg 15N plant−1), respectively. Correlation analysis showed that, under the W-N interaction, C-N metabolism enzymes promoted the positive synergistic effect between 13C and 15N accumulation in panicles (r = 0.825). In addition, the change in C/N ratio can be used as an indicator of the simultaneous improvement in yield and NUE in hybrid rice.

Download Full-text

Studies of the Metabolism of Asialotransferrins: Relationship Between the Carbohydrate Composition of Bovine, Canine, and Porcine Asialotransferrins and their Metabolic Behavior in the Rabbit

Canadian Journal of Biochemistry ◽

10.1139/o74-121 ◽

1974 ◽

Vol 52 (10) ◽

pp. 845-853 ◽

Cited By ~ 13

Author(s):

M. W. C. Hatton ◽

E. Regoeczi ◽

K.-L. Wong

Keyword(s):

Negative Charge ◽

Transfer Rates ◽

Dual Isotope ◽

Isotope Tracer ◽

Native Proteins ◽

Terminal Galactose ◽

The Difference ◽

Metabolic Behavior ◽

Galactosyl Residues

The catabolism and distribution of bovine, canine, and porcine asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual-isotope tracer technique. The capillary transfer rates and the partitions between intra- and extravascular spaces of these asialotransferrins did not differ significantly from the corresponding values for the control proteins but the asialotransferrins were catabolized faster. However, the difference in catabolic rates only amounted to 13–20%, which was in the same order as established previously for rabbit asialotransferrin (15%) but was considerably less than for human asialotransferrin (350%). This behavior clearly indicates that, in contradistinction to human asialotransferrin, bovine, canine, and porcine asialotransferrins are not eliminated from the plasma of rabbits via the Ashwell–Morell pathway for asialoglycoproteins.To explain the discrepancy in the behavior in vivo of the heterologous asialotransferrins, the carbohydrate compositions of the native proteins were measured and compared. The data show that bovine, porcine, dog, and rabbit transferrins contain approximately half the amount of carbohydrate found for the human protein. Furthermore, the human asialotransferrin carbohydrate chains terminate with galactosyl residues, which can be cleaved by β-galactosidase, whereas bovine, porcine, dog, and rabbit asialotransferrins do not liberate galactose in the presence of β-galactosidase.These observations are consistent with the hypothesis that the rapid elimination of a heterologous asialotransferrin can only be expected if the terminal galactose residues are accessible and that the slightly accelerated catabolism of homologous and certain heterologous asialotransferrins is due to loss of negative charge from the protein.

Download Full-text