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In vitro production of cellulase and xylanase was common among diverse freshwater ascomycetes and their hyphomycetous anamorphs. Production of enzymes involved in lignin degradation was rare. Most isolates were capable of causing mass loss in angiosperm wood, although values were low, at approximately 10% during a 24-week period. A few isolates caused higher mass loss of up to 26.5%, and five of these were shown to solubilize significant amounts of lignin. This is the first report of lignin solubilization by freshwater fungi. Torula herbarum (hyphomycete) and Ophioceras dolichostomum (ascomycete) produced indices of lignin solubilization equivalent to those of terrestrial white-rot basidiomycetes. In all cases wood decay was 2.2- to 3-fold higher in exposed rather than submerged conditions.

Endophytic fungi were isolated from apparently healthy organs of the wild ginger Amomum siamense Criab.. including leaves, pseudostems, and rhizomes, collected from two sites in Doi Suthep-Pui National Park, Thailand. Endophytes were relatively common with an isolate prevalence of 70%-83% at the two sites sampled in the wet and dry seasons. The endophyte assemblages from the two sites were diverse and comprised 7 Ascomycetes and 26 mitosporic fungi. Colletotrichum "gloeosporioides" (Penz.) Penz. & Sacc. in Penz., Glomerella spp., xylariaceous fungi, and Phomopsis spp. were consistently dominant as endophytes on Amomum siamense, but many rare species and mycelia sterilia were also recorded. There was no significant difference between the number of isolates recovered from leaves containing vein tissues and those containing intervein tissues, independent of leaf age. Most taxa showed a preference for either leaf tissue or pseudostems. Two new Ascomycetes species. Gaeumannomyces amomi and Leiosphaerella amomi, were discovered from leaves and rhizomes, respectively, and four species of Pyricularia, including three new species, were isolated from leaves.

The 5.8S gene and flanking internal transcribed spacers (ITS1 and ITS2) of the rDNA were amplified from total DNA extracted from frond tissues of Livistona chinensis with universal and fungal-specific primers. These amplified fragments were cloned and sequenced. Phylogenetic analysis based on the 5.8S gene sequences indicated that the six clone sequences obtained were of different origins. Five sequences, P1-9, P2-6, P4-4, P4-5, and P4-7, belonged to the fungi and one sequence, P3-2, belonged to the plants. P1-9 was inferred to belong to the Basidiomycota based on the phylogenetic analysis of the 5.8S gene sequences but could not be identified to lower taxonomic levels. Further identification of the other four fungal clones to lower taxonomic levels was attempted based on phylogenetic analysis and sequence comparison of both the conserved 5.8S gene and the variable ITS regions. The origin of P2-6 was identified to be Glomerella and its anamorph Colletotrichum, the origins of P4-5 and P4-7 were Mycosphaerella and its anamorph Cladosporium, and the origin of P4-4 was the Herpotrichiellaceae. The direct approach to detection and taxonomic placement of endophytic fungi within host tissue without the need for conventional in vitro culturing is discussed., (Copyright 2001 Academic Press.)

The diversity of wood-inhabiting fungi was investigated by submerging woody baits at upstream and downstream sites of the Lam Tsuen and Tai Po Rivers in Hong Kong. The diversity of fungi in the Lam Tsuen River was also compared with that on natural woody substrates found in a previous study. There were differences in the species composition between the upstream and downstream sites, possibly reflecting natural variations along the river. The Tai Po River downstream was organically polluted, which appeared to have little effect on species diversity since more species were recorded. Organic pollution may, however, cause a shift in species composition. The fungal communities on baits and natural substrates in the Lam Tsuen River were similar, although a lower diversity was observed on baits. This may be related to the period of submergence and the fact that a single wood type was used. Cercophora spp. occurred frequently downstream in the Tai Po River, while the common species in the Lam Tsuen River were Aquaticola rhomboidea and Pseudoproboscispora aquatica. Further interpretation on the effects of organic pollution was limited because of single collection data but appropriate experimental designs--putting baits in unimpacted sites for assessing human impacts in streams--are suggested.

Fresh specimens of Sporormiella obtained from the dung of African elephant, Cape buffalo, dikdik, giraffe, impala and waterbuck and incubated in a moist chamber were examined. Sporormiella herculea, S. intermedia, S. leporina, S. minima, S. aff. minipascua, S. aff. muskokensis, Sporormiella sp. and Sporormiella aff. teretispora were observed and described. A new record Sporormiella leporina and three unidentified species S. aff. minipascua, Sporormiella sp. and Sporormiella aff. teretispora are illustrated. Sporormiella minima, S. intermedia and S. aff. minipascua are the most common on wildlife dung examined. [ABSTRACT FROM AUTHOR]

The coprophilous fungi on cattle dung (Bos taurus) were investigated at Dahuadian and Zhongdian grasslands, in Yunnan Province, China. Fifty dung samples from Dahuadian and 50 from Zhongdian were collected and examined for fungi. A total of 61 species were recorded in this study (47 species from Dahuadian and 27 from Zhongdian) including 15 new records for mainland China. Species occurrence, species frequency, species richness, Shannon-Weiner index (H'), species evenness (E) and Sørensen's index of similarity (S') from the two grasslands were calculated. The fungal diversity from Dahuadian (altitude: 2940 meters) was higher than that from Zhongdian (altitude: 3300 meters). The proportion of ascomycetes (70%) to basidiomycetes (19%) from Zhongdian was much larger than the proportion of ascomycetes (54%) to basidiomycetes (15%) from Dahuadian. The reason for differences in fungal communities are discussed. [ABSTRACT FROM AUTHOR]

The article presents information on the ultrastructure of Asci and Ascospore appendages in Linocarpon appendiculatum and L. nipae. Ascus structure, especially that of the apical apparatus, may have a significant diagnostic value in the classification of unitunicate ascomycetes at the family level. Ascospore appendage ontogeny and ultrastructure on the other hand, are probably more useful in delimiting genera. The mature ascus wall in Linocarpon appendicula turn and L. nipae comprised a single granular, electron-dense layer of about the same thickness.

Abstract The role of the homokaryotic life stage in the dynamics of fungal communities is relatively unknown. However, homokaryons are thought to be only a temporary stage and are therefore not generally used in ecological experiments with fungi. In this study, the relative competitive ability and growth rates of homokaryons and heterokaryons of wood decay fungi were tested to assess the potential role of homokaryons in community dynamics. A homokaryon and a heterokaryon of each of four species (Aleurodiscus lividocoeruleus, Peniophora sp. 1, Peniophora sp. 2 and Pereniporia medulla-panis ) were assessed for their competitive abilities on an agar medium. The relationship between nuclear status and competitive ability varied between species. The homokaryon of Peniophora sp. 2 was competitively superior to its heterokaryon, whereas the homokaryon of Peniophora sp. 1 was inferior to its heterokaryon. A hierarchy of competitive abilities of each isolate revealed that Pereniporia medulla-panis homokaryon = P. medulla-panis heterokaryon > Peniophora sp. 1 heterokaryon > Peniophora sp. 2 homokaryon > Peniophora sp. 2 heterokaryon > A. lividocoeruleus heterokaryon = A. lividocoeruleus homokaryon. This experiment indicates that homokaryons as well as heterokaryons have the potential to influence community structure through competitive effects. [ABSTRACT FROM AUTHOR]