Cowitch seed agar medium--a simple new medium for identification and melanin production of Cryptococcus neoformans.

A simple medium for identification and melanin production of Cryptococcus neoformans was developed using cowitch (Mucuna pruriens) seeds.

Is moderation of protease production an adaptation of well-defined anthropization in dermatophytes?

The protease activity of different isolates of dermatophytes representing different ecological groups namely geophilic, zoopahilic and anthropophilic, in their vegetative and sporulation growth phases were compared. Unlike their geophilic and zoophilic counterparts, all the isolates of anthropophilic dermatophytes viz. Trichophyton rubrum, T. mentagrophytes, T. tonsurans, T. violaceum and Epidermophyton floccosum recorded reduced protease activity during artificially induced sporulation phase in comparison to their vegetative growth phase. Even among the anthropophilic group, a classical moderation of protease activity was recorded in Trichyphyton rubrum which also correlates to its clinical manifestation. This enzyme moderation could also be an evolutionary adaptation of the anthropization of these species.

Role of Chrysosporium keratinophillum in the parasitic evolution of dermatophytes.

Anti-dermatophytic activity of Chrysosporium keratinophillum against species of the genera Trichophyton, Microsporum and Epidermophyton floccosum was tested in vitro. When C. keratinophillum and different species of dermatophytes were inoculated on Sabouraud's dextrose agar plates 2 cm apart, no antagonistic effect of C. keratinophillum on the mycelial growth of dermatophytes was observed. However, conidia production was not observed on the hyphae of Trichophyton rubrum, Trichophyton tonsurans and E. floccosum grown near C. keratinophillum. The secretory substances released by C. keratinophillum inhibited the growth of T. rubrum, T. tonsurans, Trichophyton mentagrophytes var. interdigitale and E. floccosum at a concentration of 2,000 microg ml(-1) when tested by broth dilution technique. No inhibition of the growth was observed for Microsporum gypseum and Microsporum nanum. The anti-fungal activity of secretory substances released by C. keratinophillum was recorded to be heat stable. Results of the present study suggest that the anti-dermatophytic activity of the secretory substances of C. keratinophillum on T. rubrum, T. mentagrophytes var. interdigitale, T. tonsurans and E. floccosum may be responsible in part, for the absence of these dermatophyte species in soil. Considering the global prevalence of C. keratinophillum in soil one may speculate that the anti-dermatophytic activity of C. keratinophillum is one of the early events for the evolutionary divergence of saprophytic archi-dermatophytes to obligate parasitic dermatophyte species.

Prevalence, serotypes and mating patterns of Cryptococcus neoformans in the pellets of different avifauna in Madras, India.

A total of 887 pellets of different avifauna were screened for the presence of Cryptococcus neoformans. One hundred and six of 887 samples (12%) yielded Cr. neoformans in culture. The report on the isolation of Cr. neoformans from the pellets of the crow appears to be new and of greater significance because of the ubiquitous prevalence of this bird in India. The prevalence of both MAT a and MAT alpha mating types were recorded. The serotype D was predominant over serotype A. The findings of the present study reveal the growing diverse ecological niche of Cr. neoformans in a the pellets of various avifauna in India.