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Determination of 13C-enrichment in bacterial fatty acids using chemical ionization mass spectrometry with negative ion detection

Tunlid, Anders LU ; Ek, Hans ; Westerdahl, Gunilla and Odham, Göran (1987) In Journal of Microbiological Methods 7(2-3). p.77-89
Abstract

Saturated, monoenoic and β-hydroxysubstituted fatty acids, 13C-labelled at the carboxyl group, were prepared from natural or synthetic unlabelled analogues. The synthetic route involves decarboxylation of the unlabelled fatty acid to the next lower iodide, displacement of iodide for [13C]cyanide and hydrolysis. The fatty acids were converted to their pentafluorobenzyl esters and analysed by selected ion monitorint using chemical ionization and negative ion detection. Measurements of the signal ratios for the negative carboxylate ion (m) and the (m + 1) ion showed that at 95% confidence level and n = 5, mean values differing by 1.0 atom% 13C will be significantly resolved. The calculated standard... (More)

Saturated, monoenoic and β-hydroxysubstituted fatty acids, 13C-labelled at the carboxyl group, were prepared from natural or synthetic unlabelled analogues. The synthetic route involves decarboxylation of the unlabelled fatty acid to the next lower iodide, displacement of iodide for [13C]cyanide and hydrolysis. The fatty acids were converted to their pentafluorobenzyl esters and analysed by selected ion monitorint using chemical ionization and negative ion detection. Measurements of the signal ratios for the negative carboxylate ion (m) and the (m + 1) ion showed that at 95% confidence level and n = 5, mean values differing by 1.0 atom% 13C will be significantly resolved. The calculated standard deviation was the same for the studied bacterial acids including the phospholipid ester-linked palmitoleic acid, β-hydroxymyristic acid in the lipopolysaccharides and β-hydroxybutyric acid in the storage polymer poly-β-hydroxyalkanoate. Sodium [1-13C]acetate or D-[13C6]glucose were pulse administered to a Gram-negative marine bacterium isolate. Phospholipid ester-linked fatty acids and β-hydroxybutyric acid showed extensive 13C-incorporation within 15 min after the pulse. After approximately 60 min a maximum of 10 atom% excess of 13C was reached for palmitoleic acid. The method provides the potential to measure the metabolic activity of bacterial communities by measuring the incorporation of 13C-labelled substrates into specific fatty acids that can be utilized as biomarkers for biomass, community structure and nutritional status.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
C-enrichment, Bacterial acids, Negative ion chemical ionization, Phospholipid ester-linked fatty acids, Poly-β-hydroxybutyrate, Selected ion monitoring, Stable isotope labelling
in
Journal of Microbiological Methods
volume
7
issue
2-3
pages
77 - 89
publisher
Elsevier
external identifiers
  • scopus:38249034390
ISSN
0167-7012
DOI
10.1016/0167-7012(87)90028-5
language
English
LU publication?
yes
id
f2ae48df-adc7-44ee-b2c9-3e2a44748f35
date added to LUP
2019-10-23 17:29:25
date last changed
2020-01-13 02:28:40
@article{f2ae48df-adc7-44ee-b2c9-3e2a44748f35,
  abstract     = {<p>Saturated, monoenoic and β-hydroxysubstituted fatty acids, <sup>13</sup>C-labelled at the carboxyl group, were prepared from natural or synthetic unlabelled analogues. The synthetic route involves decarboxylation of the unlabelled fatty acid to the next lower iodide, displacement of iodide for [<sup>13</sup>C]cyanide and hydrolysis. The fatty acids were converted to their pentafluorobenzyl esters and analysed by selected ion monitorint using chemical ionization and negative ion detection. Measurements of the signal ratios for the negative carboxylate ion (m) and the (m + 1) ion showed that at 95% confidence level and n = 5, mean values differing by 1.0 atom% <sup>13</sup>C will be significantly resolved. The calculated standard deviation was the same for the studied bacterial acids including the phospholipid ester-linked palmitoleic acid, β-hydroxymyristic acid in the lipopolysaccharides and β-hydroxybutyric acid in the storage polymer poly-β-hydroxyalkanoate. Sodium [1-<sup>13</sup>C]acetate or D-[<sup>13</sup>C<sub>6</sub>]glucose were pulse administered to a Gram-negative marine bacterium isolate. Phospholipid ester-linked fatty acids and β-hydroxybutyric acid showed extensive <sup>13</sup>C-incorporation within 15 min after the pulse. After approximately 60 min a maximum of 10 atom% excess of <sup>13</sup>C was reached for palmitoleic acid. The method provides the potential to measure the metabolic activity of bacterial communities by measuring the incorporation of <sup>13</sup>C-labelled substrates into specific fatty acids that can be utilized as biomarkers for biomass, community structure and nutritional status.</p>},
  author       = {Tunlid, Anders and Ek, Hans and Westerdahl, Gunilla and Odham, Göran},
  issn         = {0167-7012},
  language     = {eng},
  month        = {12},
  number       = {2-3},
  pages        = {77--89},
  publisher    = {Elsevier},
  series       = {Journal of Microbiological Methods},
  title        = {Determination of <sup>13</sup>C-enrichment in bacterial fatty acids using chemical ionization mass spectrometry with negative ion detection},
  url          = {http://dx.doi.org/10.1016/0167-7012(87)90028-5},
  doi          = {10.1016/0167-7012(87)90028-5},
  volume       = {7},
  year         = {1987},
}