Biological activities of selected basidiomycetes from Yemen.

In a previous paper we demonstrated the results of biological screening of Yemeni basidiomycetes. The present study was aimed to investigate the antimicrobial and the antioxidant activity of further basidiomycetes collected in Yemen. Dichloromethane, methanol and aqueous extracts of the fruiting bodies of 25 species were screened in vitro for their antibacterial activities against three Gram-positive bacteria (Staphyloccocus aureus, Bacillus subtilis, Micrococcus flavus) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), against six human fungal pathogens (Candida albicans, Candida krusei, Aspergillus fumigatus, Mucor sp., Microsporum gypseum, Trichophyton mentagrophytes) and against one non human pathogenic fungus (Candida maltosa). The results indicated that 75 extracts exhibited activity against one or more of the bacteria. The methanol extracts of Agaricus cf. bernardii, Agrocybe pediades, Chlorophyllum molybdites, Coriolopsis polyzona, Ganoderma xylonoides, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata showed activity against all tested bacteria. The highest antibacterial activity was exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides and Trametes cingulata and Agaricus cf. bernardii, Agrocybe pediades, Coriolopsis polyzona, Pycnoporus sanguineus and Trametes lactinea. The methanol extracts of Chlorophyllum molybdites, Ganoderma xylonoides and Pycnoporus sanguineus showed considerable antifungal activities against the tested fungal strains. Strong antioxidative effects employing the DPPH assay were exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides, Hexagonia velutina, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata. Our previous and presented studies about 48 basidiomycetes collected in Yemen provide evidence that basidiomycetes from the Arabic region so far should attract more attention as potential source for new biologically active agents.

Antimicrobial, cytotoxic and antioxidant activity of selected basidiomycetes from Yemen.

Dichloromethane, methanol and aqueous extracts of 23 selected Basidiomycetes species fruiting bodies collected in Yemen were screened in vitro for their antibacterial activities against three Gram-positive bacteria (Staphyloccocus aureus, Bacillus subtilis, Micrococcus flavus), two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and against one yeast fungus (Candida maltosa), as well as for their cytotoxic and antioxidant activity. The highest antibacterial activity was shown by extracts from Agaricus sp. (Type 1), Coriolopsis caperata, Ganoderma colossus, Ganoderma resinaceum, Phellorinia herculea and Tulostoma obesum. Strong antioxidative effects employing the DPPH assay were exhibited by methanol extracts from Ganoderma resinaceum, Inonotus ochroporus, Phellinus rimosus and Phellorinia herculea. The results provide evidence that some of the studied fungi might be potential sources for new biologically active agents.

Distribution, ecology, and immunosuppressive properties of Tricholoma populinum (Basidiomycetes).

Tricholoma populinum is widely distributed in Europe and North America. In the GDR 110 localities have been recorded, ranging from sea level to 470 m s.m. It is associated with many Populus spp. on acidic and neutral ground; its frequency has locally increased by recultivation of slap-dumps and waste land with poplars. Maximum of fructification is in the first decade of October. Investigations, stimulated by empiric observations on immunosuppressive effects of the mushroom in allergic diseases of man, lead to isolation of ergosterol peroxide as one substance responsible for these effects.

[Dimorphism in fungi--a gray zone for taxonomy?]. / Dimorphismus im System der Pilze--Grauzone der Taxonomie?

Dimorphic fungi can grow as mycelial phase and as yeast phase. The change of growth form is effected by an altered programme in gene expression, which is induced either in certain stages of ontogenesis or by environmental factors. Therefore it is necessary to distinguish ontogenetically conditioned (irreversible) and environment conditioned (reversible) dimorphism. The first is characteristic for dimorphic Ustomycetes, Basidiomycetes and related anamorphs as well as for Taphrinales; the second for the majority of dimorphic Ascomycetes, Endomycetes, and related anamorphs. The integration of dimorphic fungi in the systems of filamentous fungi and of yeasts--which originally have been elaborated rather independently--was difficult in many cases. In recent times, the study of certain ultrastructural and biochemical-physiological characters has much facilitated the taxonomic arrangement of dimorphic fungi and has allowed to demonstrate some phylogenetic relations among filamentous, dimorphic, and yeast fungi. The authors hold the concept that yeasts have evolved from filamentous resp. dimorphic fungi by neotenic simplification.

[The definition of the term "mold"]. / Zur Bestimmung des Begriffs "Schimmelpilze".

The term "moulds" refers to an ecological category, not to a taxonomic or morphological one. Moulds can be characterized by 1. ruderal life strategy, 2. filamentous growth form, 3. fast growth, 4. high sporulation capacity, 5. predominantly vegetative reproduction, 6. parasexual cycle, 7. sensitivity to soil fungistasis, 8. ubiquitous occurrence, 9. cosmopolitan distribution, 10. production of a rich spectrum of metabolites (including diversified secondary metabolites, in contrast to yeasts) released into substrates resp. media. These properties qualify the moulds and antagonists of man, but also as particularly useful tools of general and industrial microbiology.

[Sporothrix nivea n. sp.--a methanol- and hydrocarbon-metabolizing fungus]. / Sporothrix nivea n. sp.--ein Methanol und Kohlenwasserstoffe verwertender Pilz.

Two fungal strains of the genus Sporothrix, isolated from industrial waste water, were characterized with respect to some morphological and physiological properties. After comparison with other species of the genus Sporothrix, the fungal strains are described as Sporothrix nivea, n. sp. Among 28 carbon sources tested, such as sugars, polysaccharides, alcohols, organic acids, and hydrocarbons, 23 are utilized. The most remarkable property of Sporothrix nivea is the utilization of both n-alkanes and methanol.