Malassezia spp. yeast habituating the skin of healthy humans can be a source of allergens for patients with atopic dermatitis. We proposed a method for obtaining allergen-containing preparation by trimming outer cell wall proteins with 1% sodium dodecyl sulfate. The resultant preparation contained 36 and 67 kD proteins known as Malassezia allergens. IgE antibodies to these proteins were detected in the sera of young people with atopic dermatitis.
We developed a scheme of consecutive replacement of complex components of a known Brucella medium containing peptones and blood with simple analogs and created a synthetic medium for Helicobacter pylori culturing. H. pylori cells require hemic iron for their growth; an appreciable increment in biomass was ensured by hemoglobin, but not simpler hemocontaining compounds (hemin and cytochrome C). Glutamine (20 g/liter) was used as the main nitrogen-containing component, and other amino acids were added in trace amounts. Adhesion was provided by adding agarose gel (0.1%) also promoting the increase in biomass. The proposed medium of a certain chemical composition differs from the known foreign analogs by the presence of hemocontaining component (hemoglobin), short period of exponential growth, and appreciable accumulation of cell protein.
Studies of two recent decades provided ample data on antibacterial peptides protecting animal and human epithelium of different types; however, no reports about the presence of these compounds in hair keratinocytes appeared up to the present time. Peptides were extracted from specimens of normal intact hair with citric acid solution in 50% ethanol. Antibacterial activity of the resultant extracts was evaluated on Candida albicans test culture by staining and microscopy, by evaluation of growth inhibition zones, and by inoculations. Direct contact with the extract destroyed the greater part of Candida albicans cells up to complete destruction of membranes. Application of the extract to dishes with agar with Candida albicans led in the formation of apparent zones of growth inhibition. The percentage of killed cells increased with prolongation of incubation with the extract. Electrophoresis of hair extract showed bands characteristic of antibacterial peptides RNase, psoriasin, and β-defensins. Removal of the peptides from the extract by filtration through membrane filter led to loss of its activity. The results indicate that human hair keratinocytes possess congenital antibacterial immunity.
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