The morphology of Candida albicans in two different Earle base media in the presence of tunicamycin.

The effect of tunicamycin on the morphology of Candida albicans yeast cells and germ tubes grown in two different Earle's minimal essential media was investigated. Tunicamycin inhibited germ tube and mycelia formation. Inhibition increased the size and caused aberrant morphology of yeast cells, including bud formation. These cells are hydrophobic and could be used for the production of two monoclonal antibodies suitable for the study of adhesion phenomena as well as ectomural properties.

Evaluation of the susceptibility of dermatophytes to antifungal drugs: a new technique.

The evaluation of the minimal inhibitory concentration (MIC) for pathogenic fungi is still a technically difficult assay. Insufficient standardization of the technique is often the basis of problems which appear. Culture characteristic of dermatophytes do not favour techniques usually used in bacteriology (Steers agar dilution method). A study was undertaken to compare the Steers agar dilution method and a new culture method to evaluate the minimal inhibitory concentration of antifungal compounds on several species of dermatophytes. The new method involves dilution of the antifungal drug in solid medium in a Petri dish. Standardized agar cylinders are cut from the plates and filled with inocula of the same size cut from plates of dermatophyte cultures. Such inocula facilitate analysis of the fungus in its natural growth conditions in vitro without being submitted to a disruptive preparative technique. The MIC values were similar for the two methods of evaluation in spite of important differences between the inocula. The new technique is reliable, quick, and highly reproducible. It is more efficient than the Steers agar dilution method because it enables assays to be run on several strains simultaneously and avoids labour-intensive procedures for the preparation of the inocula.

Scanning electron microscopic study on the effect of tunicamycin on Candida albicans.

Scanning electron microscopy was used to study the effect of tunicamycin, an inhibitor of N-glycosylation, on the morphology of Candida albicans grown in minimal essential medium Earle's base and supplemented with 0.5% N-acetyl-D-glucosamine to stimulate germ tube induction. Addition of the drug prevented development of germ tubes, development of mycelia from germ tubes and resumption of germ tube growth after drug removal. Inhibited cells increased in size during treatment and subsequently became misshapen and shrivelled with evidence of cytoplasmic spillage.

Variations in the antigenic effects of tunicamycin on Candida albicans.

We report on the effect of subinhibitory doses of tunicamycin on Candida albicans cells (BP strain high responder NCYC 1466) in a defined medium favourable for expression of the mycelial phase. Tunicamycin inhibited the synthesis of some protein fractions ranging from 40 to 65 kDa, where the immunodominant antigens of C. albicans responsible for the antibody response to systemic mycosis were inhibited. By two-dimensional immunoelectrophoresis, antigen extracts from the cell cultures grown with tunicamycin showed a migration modification and a lower number of precipitation arcs with variation in their height and range.

In vitro antifungal activity of saperconazole (R 66905) against Candida and Torulopsis.

The susceptibility of several strains of Candida and Torulopsis to saperconazole, a new triazole antifungal compound, was compared to that of ketoconazole. The MICs of the two antifungal agents were determined against 70 strains of Candida albicans, 10 strains of C. guilliermondii, 10 strains of C. krusei, 10 strains of C. parapsilosis, 10 strains of C. pseudotropicalis, 10 strains of C. tropicalis and 15 strains of Torulopsis glabrata. The fungistatic activity was evaluated by the agar dilution method using BHI and casitone media after incubation for 48 hours at 28-30 degrees C. The in vitro activity of saperconazole was similar to that of ketoconazole for most of the Candida spp. tested except for C. krusei in particular. An MIC of less than or equal to 3.12 micrograms/ml for saperconazole was found with 92% of the C. albicans strains tested. In contrast, T. glabrata was more susceptible to ketoconazole.

[Comparative action of 8 azole derivatives against Candida albicans: fungistatic action and cytologic study by scanning electron microscopy]. / Activité comparée de huit composés azolés sur Candida albicans: pouvoir fongistatique et cytologie en microscopie électronique à balayage.

The authors compared the in vitro antifungal activity of eight imidazole derivatives (clotrimazole, econazole, isoconazole, ketoconazole, miconazole, oxiconazole, terconazole, tioconazole) against 42 strains of Candida albicans by the agar dilution method using casitone medium. The geometric (G) mean MIC values, the MIC 90 and the MIC 50 values and the corresponding standard deviations of each antifungal agent were determined. The G-MIC values were found to be in the range of 0.008-0.390 micrograms ml-1. The effects of these eight antifungal agents on the ultrastructure of C. albicans yeast cells and spheroplasts were studied by scanning electron microscopy (SEM). The results showed a good correlation between the lesions observed and the structure of the imidazole derivatives tested. On the basis of the SEM results, the compounds could be divided into three groups: (1) ketoconazole and terconazole; (2) econazole, isoconazole, miconazole, oxiconazole and tioconazole; (3) clotrimazole.

A novel antibody overlay technique for two-dimensional immunoelectrophoresis.

A new antibody overlay technique for 2-dimensional immunoelectrophoresis (2-D-IEP) is described. After the first dimension electrophoresis of the antigen, the desired amount of antiserum is applied to the initial agarose layer and then evenly distributed over a defined surface of the gel with a PVC film. This modification of the conventional 2-D-IEP procedure makes it possible to perform tandem 2-D-IEPs comparing 2 antisera on the same gel plate, rocket IEPs where several antisera are compared by electrophoresis on the same gel plate, and 2-D-IEPs with an intermediate antiserum, avoiding the need to pour an intermediate gel. With this technique, 77 antigens have been demonstrated in a Candida albicans serotype A somatic antigen preparation. This is the first description of such a large number of immunoprecipitates on the same immunoplate.