Submicroscopic morphology of Trichophyton mentagrophytes grown at different temperatures

Antimicrobial activity of protoanemonin, a lactone from ranunculaceous plants

Protoanemonin, a component of Ranunculus bulbosus, was tested as an antifungal agent on selected strains of dermatophytes and yeasts. The minimum inhibitory concentrations ranged from 2.0 to 7.5 X 10(-4) M and the minimum lethal concentrations from 3.8 X 10(-4) M to greater than 1.0 X 10(-3) M. The most sensitive dermatophyte tested was Epidermophyton floccosum, and the most sensitive yeast Rhodotorula glutinis. The effects of different culture media and of light on the sensitivity of Rhodotorula glutinis to protoanemonin were also tested. Structural analogies between protoanemonin and other cytotoxic unsaturated lactones, and the reversal by the amino acid cysteine of the antifungal action suggest a possible mechanism of action.

Antifungal properties of some pyrazolyl-alkyl-sulfides. Electron microscopic evidence in two dermatophytes and Candida albicans

Four 5-amino-4-alkylthio-pyrazoles were synthesized and their antifungal activity was evaluated in vitro in Trichophyton mentagrophytes, Microsporum cookei and Candida albicans. The compounds slightly influenced the growth kinetics of the yeast, but at concentrations ranging from 20 to 40 micrograms/ml completely prevented the mycelial growth of the two dermatophytes cultivated on Sabouraud's agar medium. An electron microscopic study, undertaken by using the most active compound, showed that in C. albicans mitochondria were the only cell targets affected whereas in the dermatophytes cell wall, plasmalemma and the main cytoplasmic organelles were damaged in various degrees. Since the most remarkable alterations were connected with membrane abnormalities, the cytological changes observed were tentatively interpreted as a consequence of the compound intrusion into the lipid bilayer of the membranes, since the drug is lipophilic in nature.

Comparison of gentamicin with other antibacterials and variation of incubation temperature on growth of trichophyton mentagrophytes from skin scales

Neutral (Emmons modification) Sabouraud medium, Dermatophyte Test Medium and Littman oxgall agar, with substitutions in type of antibacterial antibiotic, were quantitatively evaluated by colony counts for ability to support growth when suspensions of trypsintreated guinea pig skin scales, infected with Trichophyton mentagrophytes, were used as inocula. Both liquid and powder form of gentamicin sulfate were used separately in place of other routinely used antibacterial antibiotics. Also evaluated were three isolation temperatures. No differences in ability to support growth were noted among media. No difference was noted between the two forms of gentamicin. No data were available on the antibacterial activities of the antibiotics because no bacterial growth was produced on any of the media. Room temperature (24 degrees-26 degrees C), 30 degrees C and 37 degrees C were found to support growth similarly as primary isolation temperatures for this fungus.

Carotenogenesis associated with arthrosporulation of Trichophyton mentagrophytes

Carotenoid pigments were demonstrated in arthrospores of the dermatophyte Trichophyton mentagrophytes but were absent from hyphae and microconidia of this fungus. Incubation at higher temperatures (39 degrees C) allowed arthrosporulation to occur, but essentially no carotenoid was detected in such arthrospores. The carotenoid formation in arthrosporulating T. mentagrophytes did not appear to be either induced or stimulated by light illumination. Mature arthrospores contained the carotenoids phytoene, phytofluene, zeta-carotene, neurosporene, lycopene, and gamma-carotene and a few minor unidentified carotenoids. These carotenoids were localized within intracellular granules consisting of osmiophilic matrices and complex membranous elements. This is the first demonstration of carotenoid pigments in dermatophytic fungi.