Lipids of dermatophytes. III. Sterol-induced changes in the lipid composition and functional properties of Epidermophyton floccosum.

Sterol supplementation, alone or in the presence of cerulenin, resulted in an increase in the total sterol content of Epidermophyton floccosum. While the total phospholipid levels of E. floccosum exhibited only marginal changes with sterol supplementation, the fatty acid profiles of these phospholipids were highly varied. In the presence or absence of cerulenin, the oleic acid content of phospholipids were increased significantly by cholesterol supplementation, whereas linoleic acid levels were enhanced by ergosterol supplementation. These variations resulted in higher unsaturated/saturated phospholipid fatty acid ratios in sterol-supplemented cells. The uptake of labeled amino acids (aspartic acid, lysine, glycine) was influenced by sterol supplementation. Alterations in the number of binding sites for the membrane probe, 1-anilino-naphthalene-8-sulfonate (ANS), were seen based on Scatchard plot calculations. The results indicate a correlation between sterol-induced changes in membrane lipid composition and function.

Fatty acids of dermatophytes.

The cellular fatty acids (C11-C20) from 18 species and strains within the genera Microsporum, Trichophyton, and Epidermophyton were determined by gas liquid chromatography. In addition, the effects of incubation time and temperature on fatty acid composition were investigated in selected species. The dermatophytes investigated represented anthropophilic, geophilic, and zoophilic species. Linoleic (18:2), oleic (18:1), and palmitic acid (16:0), accounted for 83.6-94.5% of the fatty acids of dermatophytes. Fatty acid composition and degree of unsaturation did not show any correlations with taxonomic status or ecological group. Incubation time influenced fatty acid composition slightly, but tendencies towards unsaturation and chain elongation were not observed. Elevated incubation temperature (37 degrees C) tended to increase the degree of total fatty acid unsaturation.

An unusual lipid in the human pathogenic fungus Epidermophyton floccosum.

The dermatophyte Epidermophyton floccosum contains an unusual lipid characterized as 1(3),2-diacylglyceryl-3(1)-O-4'-(N,N,N-trimethyl)homoserine. Its concentration in E. floccosum is approx. 15% of the polar lipids. The role of this lipid in the biosynthesis of polar lipids and fatty acids is not yet known. However, it is interesting from a chemotaxonomic viewpoint that the lipids from two other genera of dermatophyte, Microsporum cookei and Trichophyton rubrum do not contain this novel lipid.

Isolation of a peptido-polysaccharide from the dermatophyte Epidermophyton floccosum and a study of its reaction with human C-reactive protein and a mouse anti-phosphorylcholine myeloma serum.

Culture filtrate extracts from a number of dermatophyte and Aspergillus species precipitate with human C-reactive protein (CRP) and the lectin Con A. Using immobilized Con A, a peptidopolysaccharide (PPS) has been isolated from Epidermophyton floccosum culture filtrate by affinity chromatography and shown to precipitate with Con A, human CRP sera and a mouse myeloma serum with specificity for phosphorylcholine (PC). The PPS contains carbohydrate (60%), protein (35%), choline and phosphate. The carbohydrate portion consists almost entirely of D-mannose with only 2% hexosamine. Amino acid analysis revealed that serine, threonine, proline and glycine accounted for over 50% of the total amino acids present. Precipitation of E. floccosum PPS and pneumococcal C substance with human CRP sera and mouse anti-PC serum were compared in quantitative precipitin studies. Inhibition studies demonstrated that PC is a potent inhibitor of the serum CRP-PPS and myeloma protein-PPS precipitation reactions. The involvement of 'C substances' in a variety of biological processes is discussed.

Contribution to the study on fatty acids of Epidermophyton floccosum.

The total lipid content of a dermatophyte, Epidermophyton floccosum, grown under controlled environmental conditions, varies with growth stage and represents 7.0 to 19.8% of the dry weight. The main lipid classes, determined by quantitative thin-layer chromatography, were: triglycerides, free fatty acids, sterols and phospholipids. The fatty acid composition was established with the aid of combined gas chromatography-mass spectrometry. The major components, linoleic, palmitic and stearic acids represent 42.8, 18.9 and 9.6 per cent respectively. The fatty acid biosynthesis, their taxonomic value and their role in the disease mechanism are discussed.

Isolation, ultrastructure and chemical composition of the outermost layer ("exo-layer") of the Epidermophyton floccosum cell wall.

The outer-most layer ("exo-layer") of the wall was isolated from cell walls of Epidermophyton floccosum. The pure cell walls, obtained by disruption in a Ribi cell fractionator, sonication and centrifugation, were digested with snail enzyme for 12 h. Thereafter, the exo-layer preparation was obtained as the fraction resistant to the snail enzyme. Electron microscopy showed that the exo-layer is a thin, stranded network structure 10-20 nm thick. Chemical analysis of the exo-layer showed that the main components are protein (63 percent), mannose (10 percent) and glucosamine (17 percent). Sodium dodecyl sulfate polyacrylamide gel electrophoresis has revealed that the main band is a glycoprotein containing mannose.

Carbohydrate composition of the isolated cell walls of dermatophytes.

In an attempt to evaluate taxonomic character of sugar composition of dermatophytes, the purified cell walls from 13 species are analyzed on neutral sugar composition by gas liquid chromatography. The results were principally compatible with those obtained by conventional morphological examination. Neutral sugar components of dermatophytes cell walls were mannose and glucose in the ratio of 1:2.7 for Epidermophyton and 1:1.4 for Microsporum. There were two types in Trichophyton, in which the ratios of mannose to glucose were 1:1.6 and 1:3.8. The cases of Trichophyton ferrugineum and Trichophyton mentagrophytes were exceptional. The ratio of the former was 1:1.4, which implied the relation to Microsporum group, and the ratio of the latter was 1:2.3, which was supposed to be the intermediate of two types of Trichophyton group. Albino type cell wall of Epidermophyton floccosum was more rich in glucose than pigmented type one.