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Anal Chem

Title:		Identification of major histocompatibility complex-regulated body odorants by statistical analysis of a comparative gas chromatography/mass spectrometry experiment
Author(s):		Willse A; Belcher AM; Preti G; Wahl JH; Thresher M; Yang P; Yamazaki K; Beauchamp GK;
Address:		"Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, USA. Alan.Willse@pnl.gov"
Journal Title:		Anal Chem
Year:		2005
Volume:		77
Issue:		8
Page Number:		2348 - 2361
DOI:		10.1021/ac048711t
ISSN/ISBN:		0003-2700 (Print) 0003-2700 (Linking)
Abstract:		"This paper examines the application of gas chromatography/mass spectrometry (GC/MS) in a comparative experiment to identify volatile compounds from urine that differ in concentration between two groups of inbred mice. A complex mixture might comprise several hundred or even thousands of volatile compounds. Because their number and location in a chromatogram are generally unknown, and because components overlap in populous chromatograms, the statistical problems offer significant challenges beyond traditional two-group screening procedures. We describe a statistical procedure to compare two-dimensional GC/MS profiles between groups, which entails (1) signal processing, baseline correction, and peak detection in single ion chromatograms; (2) aligning chromatograms in time; (3) normalizing differences in overall signal intensities; and (4) detecting chromatographic regions that differ between groups. In an application to chemosignaling, we detect differences in GC/MS chromatograms of ether-extracted urine collected from two inbred groups of mice that differ only in genes of the major histocompatibility complex (MHC). Several dozen MHC-regulated compounds are found, including two known mouse pheromones, 2,5-dimethylpyrazine and 2-sec-butyl-4,5-dihydrothiazole"
Keywords:		"Animals Data Interpretation, Statistical Discriminant Analysis Gas Chromatography-Mass Spectrometry/*methods Major Histocompatibility Complex/*physiology Mice Mice, Inbred C57BL Odorants/*analysis *Signal Processing, Computer-Assisted Urine/*chemistry;"
Notes:		"MedlineWillse, Alan Belcher, Anne M Preti, George Wahl, Jon H Thresher, Miranda Yang, Peter Yamazaki, Kunio Beauchamp, Gary K eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2005/04/15 Anal Chem. 2005 Apr 15; 77(8):2348-61. doi: 10.1021/ac048711t"