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Characterization of lipopolysaccharides present in settled house dust.
Park J-H; Szponar B; Larsson L; Gold DR; Milton DK
Appl Environ Microbiol 2004 Jan; 70(1):262-267
The 3-hydroxy fatty acids (3-OHFAs) in lipopolysaccharides (LPS) play an important role in determining endotoxin activity, and childhood exposure to endotoxin has recently been associated with reduced risk of atopic diseases. To characterize the 3-OHFAs in house dust (HD), we used gas chromatography-mass spectrometry to assay 190 HD samples. Dust from beds, bedroom floors, family rooms, and kitchen floors was collected as part of a birth cohort study of childhood asthma (study 1) and a longitudinal study of home allergen and endotoxin (study 2). We also measured endotoxin activity with a Limulus assay and computed specific activity (endotoxin activity per nanomole of LPS). Longer-chain (C(16:0) and C(18:0)) 3-OHFAs were predominant in HD compared with short-chain (C(10:0), C(12:0), and C(14:0)) acids. Endotoxin activity was positively correlated with short-chain 3-OHFAs in both studies. In study 2, 3-OH C(16:0) was negatively correlated and 3-OH C(18:0) was not correlated with endotoxin activity, consistent with previous findings that the Limulus assay responds preferentially to LPS containing short-chain 3-OHFAs. Kitchen dust contained the highest concentrations of 3-OH C(10:0), the highest endotoxin activities, and the highest specific activities (P < 0.03). Bed dust contained the largest amounts of long-chain 3-OHFAs, the highest concentrations of LPS, and the lowest specific activities. Apartments had significantly different types of LPS (P = 0.03) compared with single-family homes in study 2. These data suggest that the Limulus assay may underestimate exposure to certain types of LPS. Because nontoxic LPS may have immune modulating effects, analysis of 3-OHFAs may be useful in epidemiologic studies.
Microbiology; Dust-analysis; Dust-particles; Dust-sampling; Endotoxins; Allergens; Bacterial-dusts; Biological-effects; Polysaccharides; Fatty-acids; Respiratory-system-disorders; Seasonal-factors; Children; Environmental-factors; Bioassays
Donald K. Milton, Harvard School of Public Health, Department of Environmental Health, 665 Huntington Avenue, Boston, MA 02115
Issue of Publication
Applied and Environmental Microbiology
Harvard School of Public Health
Page last reviewed: October 26, 2020
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