ISOLATION AND IDENTIFICATION OF FUNGI FROM SUBMERGED PLANTS DEBRIS IN AQUATIC HABITATS IN MISAN PROVINCE

Forty-eight taxa of saprophytes fungi were isolated and identified from submerged plant debris samples collected from different sites in Misan province, southern Iraq, which are Maymouna, Al-Salam, Majar Al-Kabir, and Amara. Among them, 24 species belonged to Ascomycota (six of which are sexual state), 19 species to hyphomycetes (anamorphic fungi), 4 to Zygomycota, and one to Oomycetes. Six species were isolated and newly recorded from Iraq, which are Aniptodera margaration, Cirrenalia iberica, Cordana lignicola, Cordana verruculosa, Pseudoacrodictys appendiculata, and Scytalidium thermophilum. However, in the evaluation of both moist chamber and direct culture methods, 34 species were isolated by the first method and 27 species by the second method, meantime, 13 species (9 belonged to Ascomycota, 2 to hyphomycetes, and 2 to Zygomycetes) were recovered by both methods. Aspergillus terrus was appeared in highest frequency and occurrence (11.76%, 42.55%, respectively), followed by Aspergillus horti (10%, 36.17%, respectively), and then A. niger with a frequency and occurrence of 5.29% and 19.14%, respectively, while 17 species were appeared lowest frequency and occurrence to reach 0.58%, 2.12%, respectively, for all. One hundred and seven isolates have been recovered from all study sites. Meantime, sixty-four isolates have been reported from Majar Al-Kabir, as compared with other sites, followed by Amara (43 isolates), while 39 isolates have been isolated from the Maymouna, and 24 isolates from Al-Salam. The biodiversity of fungi isolated from submerged plant debris was compared with previous studies. Brief descriptions of the new recorded fungi were given.

Studies on the occurrence of fungi in a whea-field. L. Mesophilic, Thermophiuc and keratinophilic fungi in soil

Desde Octubre 1982 a Julio 1983 un total de 1772 colonias fúngicas se aislaron desde suelos de trigales en Lombardía. Se estudiaron hongos mesófilos, termófilos y queratinófilos. Entre los mesófilos (59 especies) se detectan como dominantes: Fusarium oxysporum, Lipomyces starkeyi, penicillium janthinellum; como frecuentes, Cryptococcus albidus, Gibberella acuminata, Gliocladium roseum, Rhizopus stolonifer; y otros raros Bahusakala olivaceonigra, Pseudallescheria boydii, Truncotella angustata, Verticillium lecanii, Pyrenochaeta ilicis, Myrotheclum roridum, Drechslera dematioidea. Entre los termófilos (15 especies) como dominantes, Aspergillus fumigatus y Rhizomucor pusillus; frecuentes, Scytalidium thermophilum y thermomyces lanuginosus. Entre los queratinofílicos (11 especies), como dominantes Myceliophthora anamorfo de Ctenomyces serratus, Microsporum gypseum fulvum complex y Chrysosporium merdarium como frecuentes, Chrysosporium keratinophilum y Ctenomyces serratus. Durante Febrero y Abril, la incidencia de todos los grupos aumenta notoriamente.

Identification of the site of oxidase substrate binding inScytalidium thermophilumcatalase

The catalase fromScytalidium thermophilumis a homotetramer containing a hemedin each active site. Although the enzyme has a classical monofunctional catalase fold, it also possesses oxidase activity towards a number of small organics, including catechol and phenol. In order to further investigate this, the crystal structure of the complex of the catalase with the classical catalase inhibitor 3-amino-1,2,4-triazole (3TR) was determined at 1.95 Å resolution. Surprisingly, no binding to the heme site was observed; instead, 3TR occupies a binding site corresponding to the NADPH-binding pocket in mammalian catalases at the entrance to a lateral channel leading to the heme. Kinetic analysis of site-directed mutants supports the assignment of this pocket as the binding site for oxidase substrates.