The paracloacal glands are the most prevalent scent glands in marsupials, and previous investigation of their secretions in the brushtail possum (Trichosurus vulpecula) has identified many odorous compounds together with large amounts of neutral lipids. We have examined the lipids by LC–MS, generating ammonium adducts of acylglycerols by electrospray ionisation. Chromatograms showed a complex mixture of coeluting acylglycerols, with m/z from about 404 to 1048. Plots of single [M + NH₄]⁺ ions showed three groups of lipids clearly separated by retention time. MS–MS enabled triacylglycerols and diacylglycerol ethers to be identified from neutral losses and formation of diacylglycerols and other product ions. The earliest-eluting lipids were found to be triacylglycerol estolides, in which a fourth fatty acid forms an ester link with a hydroxy fatty acid attached to the glycerol chain. This is the first report of triacylglycerol estolides in animals. They form a complex mixture with the triacylglycerols and diacylglycerol ethers of lipids with short- and long-chain fatty acids with varying degrees of unsaturation. This complexity suggests a functional role, possibly in social communication.

Item Type:	Refereed Article
Keywords:	triacylglycerol, estolide, diacylglycerol ether, LC-MS analysis, GC-MS analysis, paracloacal scent glands, brushtail possum, Trichosurus vulpecula, pheromone, marsupial
Research Division:	Chemical Sciences
Research Group:	Analytical chemistry
Research Field:	Analytical spectrometry
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	McLean, S (Professor Stuart McLean)
UTAS Author:	Davies, NW (Associate Professor Noel Davies)
UTAS Author:	Nichols, DS (Dr David Nichols)
ID Code:	100115
Year Published:	2015
Web of Science® Times Cited:	8
Deposited By:	Pharmacy
Deposited On:	2015-05-04
Last Modified:	2017-10-28
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