Responses of fungi to tropane alkaloids produced by a medicinal plant Hyoscyamus muticus (Egyptian henbane).

Antifungal activity of hyoscyamine (Hcy) and scopolamine (Sco) were determined by TLC-bioautography against fungi associated with H. muticus grown in Egypt, and those isolated from other plants grown in Japan. All 40 fungal strains were tolerant to Sco and sensitive to Hcy, exhibiting a growth inhibition zone around the Hcy spot on the bioautography plate. The strains were grouped into three types based on the appearance of the inhibition zone: (i) 17 strains exhibiting a clear inhibition zone, which remained clear at 8 d after incubation (type I); (ii) 22 strains exhibiting the inhibition zone with a brown circle surrounding the zone and regrowth within the inhibition zone (type II); (iii) 1 strain exhibiting the inhibition zone with no brown circle and regrowth within the inhibition zone (type III). In the type II and III strains, Hcy disappeared, and other alkaloids were found in the inhibition zones in its place. Hcy feeding experiments using Penicillium purpurogenum (type II) and Cunninghamella elegans (type III) revealed that these fungi may convert Hcy to a new alkaloid compound.

Studies on the mycoflora of Aswan High Dam Lake, Egypt: monthly variations.

Fifty-one species and one variety appertaining to twenty one genera of mesophilic fungi were recovered from the monthly samples of marginal water (44 species, 1 variety and 18 genera) and submerged mud (78 species, 1 variety and 30 genera) of Aswan High Dam Lake during the period from July 1985 to December 1986. The most common species were Aspergillus fumigatus, A. flavus, A. terreus, A. niger and Penicillium funiculosum. The highest fungal populations were almost detected either in October, in December 1985 or in February 1986. Of the 12 thermophilic and thermotolerant fungal species, A. fumigatus and A. nidulans were the most common. Paecilomyces variotii, Rhizomucor pusillus, Thermomyces lanuginosus, Thermoascus thermophilus and Sporotrichum thermophilum were fairly common in one locality or more. The physico-chemical characteristics of water and mud samples were also followed.

Studies on the mycoflora of Aswan High Dam Lake, Egypt: vertical fluctuations.

The fungal population of Aswan High Dam Lake showed marked vertical variations during the period of study which extended from July 1985 to December 1986. High fungal counts were observed at the surface water which were mainly due to the high counts of Aspergillus fumigatus and A. terreus. Going deeper the fungal population decreased till 30 meters, then gradually increased to reach its maximum at the 70 meter depth (near the bottom of the lake). Such increase was basically due to the high population of Penicillium funiculosum. At each sampling time, the water temperature and the values of dissolved oxygen were always higher at the surface than near the bottom of the lake. The temperature ranged from 15 degrees to 26 degrees C and the dissolved oxygen from 1.31 to 8.98 mg 1(-1).