title: Quantification of ergosterol and 3-hydroxy fatty acids in settled house dust by gas chromatography-mass spectrometry: comparison with fungal culture and determination of endotoxin by a Limulus amebocyte lysate assay.
abstract: Ergosterol and 3-hydroxy fatty acids, chemical markers for fungal biomass and the endotoxin of gram-negative bacteria, respectively, may be useful in studies of health effects of organic dusts, including domestic house dust. This paper reports a method for the combined determination of ergosterol and 3-hydroxy fatty acids in a single dust sample and a comparison of these chemical biomarkers determined by gas chromatography-mass spectrometry with results from fungal culture and Limulus assay. Analyses of replicate house dust samples resulted in correlations of 0.91 (ergosterol in six replicates; P < 0.01) and 0.94 (3-hydroxy fatty acids in nine replicates; P < 0.001). The amounts of ergosterol (range, 2 to 16.5 ng/mg of dust) correlated with those of total culturable fungi (range, 6 to 1,400 CFU/mg of dust) in 17 samples, (r = 0.65; P < 0.005). The amounts of endotoxin (range, 11 to 243 endotoxin units/mg of dust) measured with a modified chromogenic Limulus assay correlated with those of lipopolysaccharide (LPS) determined from 3-hydroxy fatty acid analysis of 15 samples. The correlation coefficient depended on the chain lengths of 3-hydroxy acids used to compute the LPS content. The correlation was high (r = 0.88 +/- 0.01; P < 0.001) when fatty acid chains of 10 to 14 carbon atoms were included; the correlation was much lower when hydroxy acids of 16- or 18-carbon chains were included. In conclusion, the results of the described extraction and analysis procedure for ergosterol and 3-hydroxy fatty acids are reproducible, and the results can be correlated with fungal culture and endotoxin activity of organic dust samples.
authors.affiliation: Department of Medical Microbiology, University of Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Saraf
authors.forename: L
authors.initials: L
authors.lastname: Larsson
authors.forename: H
authors.initials: H
authors.lastname: Burge
authors.forename: D
authors.initials: D
authors.lastname: Milton
mesh_terms: D001431:Bacteriological Techniques; D015415:Biomarkers; D018533:Biomass; D004391:Dust / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004875:Ergosterol / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis*; D005658:Fungi / Q000254:growth & development*; D008401:Gas Chromatography-Mass Spectrometry; D006090:Gram-Negative Bacteria / Q000737:chemistry; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000032:analysis; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D004391:Dust; D004731:Endotoxins; D005227:Fatty Acids; D008070:Lipopolysaccharides; D004875:Ergosterol