Compound‐specific δ<sup>13</sup>C and δ<sup>15</sup>N analysis of amino acids: a rapid, chloroformate‐based method for ecological studies

Walsh, Robert; He, Shaoneng; Yarnes, Christopher T.

doi:10.1002/rcm.6761

Cited by 96 publications

(113 citation statements)

References 63 publications

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“…Individual amino acid nitrogen isotope analysis: Individual amino acids (free and protein bound) were prepared from cell lines using the chloroformate extraction technique (UC Davis Stable Isotope Facility) 22 . A recent study compares the chloroformate extraction technique favourably with other standard extraction techniques 23 .…”

Section: Resultsmentioning

confidence: 99%

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Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Krishnamurthy

Suryawanshi

Essani

2017

Sci Rep

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Glutamic acid and alanine make up more than 60 per cent of the total amino acids in the human body. Glutamine is a significant source of energy for cells and also a prime donor of nitrogen in the biosynthesis of many amino acids. Several studies have advocated the role of glutamic acid in cancer therapy. Identification of metabolic signatures in cancer cells will be crucial for advancement of cancer therapies based on the cell’s metabolic state. Stable nitrogen isotope ratios (15N/14N, δ15N) are of particular advantage to understand the metabolic state of cancer cells, since most biochemical reactions involve transfer of nitrogen. In our study, we used the natural abundances of nitrogen isotopes (δ15N values) of individual amino acids from human colorectal cancer cell lines to investigate isotope discrimination among amino acids. Significant effects were noticed in the case of glutamic acid, alanine, aspartic acid and proline between cancer and healthy cells. The data suggest that glutamic acid is a nitrogen acceptor while alanine, aspartic acid and proline are nitrogen donors in cancerous cells. One plausible explanation is the transamination of the three acids to produce glutamic acid in cancerous cells.

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Section: Resultsmentioning

confidence: 99%

“…Detailed protocol of isotope analysis can be found in ref. 22. Comparison of this method technique with other commonly used method is reported in ref.…”

Section: Methodsmentioning

confidence: 99%

Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Krishnamurthy

Suryawanshi

Essani

2017

Sci Rep

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“…According to their laboratory specifications samples were treated according to procedures described by Walsh et al [23]. Samples were hydrolyzed in 6N HCl at 150°C during 70 min under atmosphere of nitrogen, and then dried at 55°C using nitrogen gas flow and re-suspended in 1mL 0.01N HCl.…”

Section: Methodsmentioning

confidence: 99%

Metabolism of Seriola lalandi during Starvation as Revealed by Fatty Acid Analysis and Compound-Specific Analysis of Stable Isotopes within Amino Acids

Barreto-Curiel¹,

Focken

D’Abramo

et al. 2017

PLoS ONE

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Fish starvation is defined as food deprivation for a long period of time, such that physiological processes become confined to basal metabolism. Starvation provides insights in physiological processes without interference from unknown factors in digestion and nutrient absorption occurring in fed state. Juveniles of amberjack Seriola lalandi were isotopically equilibrated to a formulated diet for 60 days. One treatment consisted of fish that continued to be fed and fish in the other treatment were not fed for 35 days. The isotopic signatures prior to the beginning of and after the starvation period, for fish in the starvation and control treatments, were analysed for lipid content, fatty acid composition and isotopic analysis of bulk (EA-IRMS) and of amino acids (compound specific isotope analysis, CSIA). There were three replicates for the starvation group. Fatty acid content in muscle and liver tissue before and after starvation was determined to calculate percent change. Results showed that crude lipid was the most used source of energy in most cases; the PUFAs and LC-PUFAs were highly conserved. According to the protein signature in bulk (δ15N) and per amino acid (δ13C and δ15N), in muscle tissue, protein synthesis did not appear to occur substantially during starvation, whereas in liver, increases in δ13C and δ15N indicate that protein turnover occurred, probably for metabolic routing to energy-yielding processes. As a result, isotopic values of δ15N in muscle tissue do not change, whereas CSIA net change occurred in the liver tissue. During the study period of 35 days, muscle protein was largely conserved, being neither replenished from amino acid pools in the plasma and liver nor catabolized.

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“…General techniques for CSIA-AA are summarised below and extensively described in Walsh et al (2014). General techniques for CSIA-AA are summarised below and extensively described in Walsh et al (2014).…”

Section: Sample Processing and Isotope Analysismentioning

confidence: 99%

Reweaving river food webs through time

Bowes

Thorp

2019

Freshwater Biology

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Our project sought to determine ecological effects of adding low‐head dams and levees to large rivers by examining potential changes to aquatic food webs over a 70‐year period in the Lower Ohio River (LOR) and Upper Mississippi River (UMR). We employed museum collections of fish and compound specific stable isotope analysis of amino acids to evaluate long‐term changes in primary food sources for multiple species of fish in each river. Fishes in both rivers depended more on autochthonous than allochthonous carbon sources throughout the 70‐year period (based on measurements of isotopic signatures of algae, C3 plants, C4 plants, cyanobacteria, and fungi), but the relative use of different carbon sources differed between the UMR and LOR. Significant but opposite shifts in trophic positions (TP) between rivers over time (higher TP in the UMR; lower in the LOR) were correlated with major anthropogenic changes to habitat structure (e.g. slight decrease in abundance of side channels in the UMR; increase in pool water depth in the LOR) resulting from low‐head dam construction. They may also have been influenced by likely increased primary productivity in the UMR from agricultural nitrogen inputs and by possible shifts in the importance of phytoplankton versus benthic algae in the LOR from changes in water depth. Shifts in trophic position and reliance on various food sources were not correlated with variation in discharge, gage height, or temperature. Although these two rivers have contrasting hydrogeomorphic complexity (UMR is an anastomosing river, while the LOR is a constricted channel river) and different discharge patterns (seasonal versus yearly operation in some cases), both differ substantially from rivers having hydrogeomorphic changes resulting from construction of high dams (>15 m). It is not surprising, therefore, that factors controlling trophic position and reliance on different carbon sources vary among different types of dams and river structures.

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Compound‐specific δ¹³C and δ¹⁵N analysis of amino acids: a rapid, chloroformate‐based method for ecological studies

Cited by 96 publications

References 63 publications

Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Metabolism of Seriola lalandi during Starvation as Revealed by Fatty Acid Analysis and Compound-Specific Analysis of Stable Isotopes within Amino Acids

Reweaving river food webs through time

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Compound‐specific δ13C and δ15N analysis of amino acids: a rapid, chloroformate‐based method for ecological studies

Cited by 96 publications

References 63 publications

Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Nitrogen isotopes provide clues to amino acid metabolism in human colorectal cancer cells

Metabolism of Seriola lalandi during Starvation as Revealed by Fatty Acid Analysis and Compound-Specific Analysis of Stable Isotopes within Amino Acids

Reweaving river food webs through time

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Compound‐specific δ¹³C and δ¹⁵N analysis of amino acids: a rapid, chloroformate‐based method for ecological studies