Kuehbandner, Stephan and Ruther, Joachim (2015) Solid Phase Micro-extraction (SPME) with In Situ Transesterification: An Easy Method for the Detection of Non-volatile Fatty Acid Derivatives on the Insect Cuticle. JOURNAL OF CHEMICAL ECOLOGY, 41 (6). pp. 584-592. ISSN 0098-0331, 1573-1561
Full text not available from this repository. (Request a copy)Abstract
Triacylglycerides (TAGs) and other non-volatile fatty acid derivatives (NFADs) occur in large amounts in the internal tissues of insects, but their presence on the insect cuticle is controversially discussed. Most studies investigating cuticular lipids of insects involve solvent extraction, which implies the risk of extracting lipids from internal tissues. Here, we present a new method that overcomes this problem. The method employs solid phase micro-extraction (SPME) to sample NFADs by rubbing the SPME fiber over the insect cuticle. Subsequently, the sampled NFADs are transesterified in situ with trimethyl sulfonium hydroxide (TMSH) into more volatile fatty acid methyl esters (FAMEs), which can be analyzed by standard GC/MS. We performed two types of control experiments to enable significant conclusions: (1) to rule out contamination of the GC/MS system with NFADs, and (2) to exclude the presence of free fatty acids on the insect cuticle, which would also furnish FAMEs after TMSH treatment, and thus might simulate the presence of NFADs. In combination with these two essential control experiments, the described SPME technique can be used to detect TAGs and/or other NFADs on the insect cuticle. We analyzed six insect species from four insect orders with our method and compared the results with conventional solvent extraction followed by ex situ transesterification. Several fatty acids typically found as constituents of TAGs were detected by the SPME method on the cuticle of all species analyzed. A comparison of the two methods revealed differences in the fatty acid compositions of the samples. Saturated fatty acids showed by trend higher relative abundances when sampled with the SPME method, while several minor FAMEs were detected only in the solvent extracts. Our study suggests that TAGs and maybe other NFADs are far more common on the insect cuticle than usually thought.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CONTACT SEX-PHEROMONE; CUTICULAR LIPIDS; MASS-SPECTROMETRY; SURFACE-LIPIDS; CHEMICAL-COMPOSITION; EPICUTICULAR LIPIDS; QUEENLESS ANT; HYDROCARBONS; BEETLE; MICROEXTRACTION; Cuticular triacylglycerides; Non-volatile fatty acid derivatives; Fatty acid methyl ester; Solid phase micro extraction; Trimethyl sulfonium hydroxide; Sex pheromone |
| Subjects: | 500 Science > 590 Zoological sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Zoologie > Chemische Ökologie (Prof. Dr. Joachim Ruther) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 15 Jul 2019 06:15 |
| Last Modified: | 15 Jul 2019 06:15 |
| URI: | https://pred.uni-regensburg.de/id/eprint/5403 |
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