Partial purification and some biochemical characteristics of exocellular keratinase from Trichophyton mentagrophytes var. erinacei.

The dermatophyte Trichophyton mentagrophytes var. erinacei isolated from patients infected with tinea cruris was cultured in Sabouraud dextrose broth, from which an exocellular keratinase extract was obtained. The keratinase was partially purified with sephadix G-100 gel filtration. Some biochemical characteristics of the purified enzyme were examined. Its molecular weight was estimated to be 38,000 dalton on sodium dodecyle sulfate polyacrylmide gel electrophoresis (SDS-PAGE). The optimal pH was 5.5 and optimal temperature for the highest keratinase activity was 50 degrees C. The enzyme activity was specifically increased against guinea pig hair and fibrous protein and inhibited by phenylmethylsulfonylfluoride.

Exocellular enzyme activity of dermatophytes and other fungi isolated from ruminants in Southern Iraq.

Sixteen fungal species were isolated from 182 specimens collected from four ruminants (buffalo, camel, cattle and sheep) in Southern Iraq. Fungi represented by five species of dermatophytes and eleven species of other fungi were screened for the activity of four enzymes: keratinase. proteinase, lipase and amylase. Keratinase was found to be produced by all of the dermatophytes and non-dermatophytes, except for Paecillomyces variottii and Scytalidium lignicola. However, high keratinase activity was expressed by the dermatophytic species particularly by Trichophyton mentagrophytes var. erinacei and Microsporum gypseum. Three dermatophytes viz. M. gypseum, T verrucosum and T. mentagrophytes var. nodulare were capable of producing protease, lipase and amylase. Although, T. mentagrophytes var. erinacei showed high protease activity, it did not produce lipase and amylase. On the contrary most of the non-dermatophytic species revealed protease and lipase activities higher than the dermatophytes. The Curvularia spp. isolates showed the highest protease and amylase activity, while Aspergillus parasiticus revealed the highest activity of lipase andamylase. No correlation was observed between enzyme activity and the growth rate of the examined fungi.

Effect of garlic bulb extract on the growth and enzymatic activities of rhizosphere and rhizoplane fungi.

Eighteen fungal species were isolated from rhizospheric soil and rhizoplane samples of three plant crops in southern Iraq. The fungal isolates were examined for the activities of four enzymes (amylase, cellulase, phenoloxidase, and protease), as well as their growth, against crude garlic extract added to the culture agar medium. A high reduction or inhibition of enzymatic activities was observed for the fungi treated with garlic extract compared with untreated fungal cultures. However, most of the species showed inhibition of enzymes due to the effect of garlic extract. The growth of the fungal species was also remarkably reduced by the garlic extract.

Tinea capitis in Basrah, Iraq.

Tinea capitis is the most common type of dermatophytosis constituting 35.2% (173/491) of all cases of dermatophytosis seen at two out-patients dermatological clinics of the Basrah General Hospital and at two private dermatological clinics between October 1994 and December 1995. Males were more commonly affected than females represented by 60 and 40%, respectively. Out of 173 mycologically positive cases, 143 specimens were culture-positive, represented by five dermatophyte species; Trichophyton violaceum was the most frequent causative agent (38.5%), followed by Trichophyton verrucosum (28.7%), Microsporum canis (26.5%), Trichophyton mentagrophytes var. mentagrophytes (5.6%) and Microsporum gypseum (0.7%). Six atypical cases appeared as cases of seborrheic dermatitis or dandruff and were proved to be atypical cases of tinea capitis caused by T. violaceum.

Characteristics of dermatophytoses in Basrah, Iraq.

A total of 1199 clinical specimens were collected from 1144 patients clinically diagnosed as cases of superficial cutaneous mycoses in Basrah (Iraq). The collected specimens were examined for the etiologic agents of dermatophytoses by direct microscopy and culture. A total of 237 isolates representing eight species of dermatophytes as a causative agents of skin and nails infections were isolated. Among the tinea infections, tinea corporis and tinea cruris were the most common types of dermatophytoses revealed in this study.

Partial purification and kinetic studies of exocellular proteinase from Trichophyton mentagrophytes var. erinacei.

The dermatophyte Trichophyton mentagrophytes var. erinacei isolated from a patient with tinea cruris was cultured in peptone-glucose broth from which an exocellular proteinase was obtained. The enzyme was partly purified by Sephadex G-100 gel filtration. Its molecular weight was determined to be 33,000 on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH was 8.5, the optimal temperature 35 degrees C. The proteolytic activity was specifically increased against casein and inhibited by phenylmethylsulphonyl fluoride. The enzyme was identified as alkaline serine proteinase.

Extracellular enzyme activities of dermatophytes and yeast isolates on solid media.

A total of 123 isolates of 14 species of dermatophytes and yeasts were screened for the activity of five extracellular enzymes including elastase, keratinase, protease (gelatinase), lipase and phospholipase, by using solid media. The optimal production and activity of each enzyme was determined with regard to different pH and temperatures. Keratinase activity was high with all the tested fungi with exception of Malassezia furfur. Protease (gelatinase) was produced only by dermatophytes. Elastase was secreted by three dermatophytes viz. Microsporum gypseum, Trichophyton mentagrophytes var. mentagrophytes and T. verrucosum, whereas lipase and phospholipase were detected in all the species except T. violaceum.