A ganoderic acid derivative,a highly oxygenated lanostane-type triterpenoid from Ganoderma lucidum

Ganoderic acid C, a new lanostane-type triterpenoid was isolated from the fruit body of Ganoderma lucidum. The structure of ganoderic acid C was elucidated by spectroscopic data and X-ray analysis of methyl ganoderate C acetate.     

The active site of yeast endo-polygalacturonase contains seven subsites

The rate of hydrolysis of oligomers by the endopolygalacturonase of yeast is in the order: heptamer > hexamer > pentamer > tetramer. This suggests that the active site accommodates at least 7 units. Since the heptamer disappears concurrently with the bulk of larger oligomers, the maximum number of units appears to be 7. The release of labelled (unsaturated, or ³H labelled and reduced) end units from larger substrate is interpreted to indicate that the enzyme interacts with 3 saccharide units toward the reducing end from the bond to be broken, and with 4 units toward the non-reducing end. The relative affinities for the enzyme of saccharide units in various positions are unequal, as indicated by the very low relative rate of monomer production from the hydrolysis of hexamer and pentamer, and the apparently unequal probability of two other modes of hexamer hydrolysis [(tetramer + dimer) = 2.5 (trimer + trimer)].     

Food attraction and population growth of fungivorous nematodes with different fungi

Food attraction of the fungivorous nematodes Aphelenchus avenae and Aphelenchoides spp. to seven fungal species (Pyrenochaeta lycopersici, Botrytis cinerea, Rhizoctonia solani strains AG 3 and AG 2‐1, Verticillium dahliae, Pochonia bulbillosa, Mortierella hyalina and Trichoderma harzianum) was determined on agar plates by counting the number of test nematodes present on the mycelium of each fungus 24 h after inoculation. Population growth of A. avenae and Aphelenchoides spp. on five of the seven fungi included in the attraction test (P. lycopersici, R. solani strain AG 3, V. dahliae, P. bulbillosa and T. harzianum) was also determined on agar plates by counting nematode numbers every week during a 6‐week period. A. avenae and Aphelenchoides spp. were attracted to all the fungi tested. A. avenae was preferentially attracted to V. dahliae (P < 0.0001), and Aphelenchoides spp. did not show any preference except for low attraction to R. solani. A. avenae and Aphelenchoides spp. reproduced on all fungal species tested. After 6 weeks of incubation, the highest number of nematodes was found on P. lycopersici and P. bulbillosa, while the lowest number occurred on R. solani for A. avenae and on T. harzianum for Aphelenchoides spp. The suitability of a fungus as a host was not clearly related to the attraction to that fungus.     

Molecular analysis of Gigaspora (Glomales, Gigasporaceae)

This work presents a cooperative effort to integrate new molecular (isozyme and SSU analyses) characters into the morphological taxonomy of the genus Gigaspora (Glomales). Previous analyses of published Gigaspora SSU sequences indicated the presence of a few polymorphic nucleotides in the region delimited by primers NS71-SSU 1492'. In our study, the SSU of 24 isolates of arbuscular mycorrhizal (AM) fungi from the Gigasporaceae were amplified and the NS71-SSU 1492' region was directly sequenced. The corresponding sequences of four more isolates of AM fungi from Gigasporaceae, already published, were also included in our analyses. Three Gigaspora groups were identified on the basis of a 6 nucleotide-long 'molecular signature': Gigaspora rosea group ( G. rosea + G. albida ), Gigaspora margarita group ( G. margarita + G. decipiens ) and Gigaspora gigantea , which constituted a group by itself. The isozyme profiles (malate dehydrogenase, MDH) of 12 of these 28 isolates, and seven other isolates not sequenced, were compared. The results obtained further supported the grouping of isolates provided by the SSU analysis. Both SSU and MDH analysis indicated that two out of the 35 isolates had been misidentified, which was confirmed when their morphology was reassessed. The use of the Gigaspora intrageneric molecular signature as a quick, unambiguous and objective method to recognize Gigaspora isolates under any (field or laboratory) experimental conditions is suggested.     

Some coprophilous fungi from Kenya

The occurrence of coprophilous fungi on samples of antelope, buffalo, zebra and hippopotamus dung collected from the Marula Estates in Kenya was recorded. A hundred and seventy three fungal isolates representative of 40 genera and 59 species were identified. Among these species, 23 were Ascomycetes (39%), 30 Deuteromycetes (50.8%), 5 Zygomycetes (8.5%) and 1 Basidiomycete (1.7%). Ascobolus immersus, Coprotus niveus, Iodophanus carneus, Lasiobolus lasioboloides, Podospora anserina, P. australis and Sporormiella minima were the dominant species occurring in the dung of these animals. Notes on infrequent or interesting Ascomycetes include Kernia nitida, Saccobolus versicolor, Sordaria fimicola and others. The interdependence of the vegetation of this area with the fungi occurring on the dung of these animals is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Survey of keratinophilic fungi isolated from city park soils of Pisa,Italy

A survey of geophilic dermatophytes and related keratinophilic fungi isolated from city park soils of Pisa is reported. Twenty-three (48%) soil samples out of 48 were positive by hair baiting. The following species were isolated: Microsporum gypseum (39%), Trichophyton ajelloi (31%), Chrysosporium keratinophilum (14%), T. terrestre (8%), M. fulvum, Ch. luteum, Ch. indicum (5% each) and M. cookei (2%). The presence of the different species is discussed in relation to the risk of fungal skin infections. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cloning and sequence analysis of Histoplasma capsulatum glucosamine-6-phosphate synthase gene fragment

The 3' part of the glucosamine-6-phosphate synthase gene from Histoplasma capsulatum was PCR amplified using degenerate primers designed from the known glucosamine-6-phosphate synthase gene sequences, cloned and sequenced. The computer analysis of the 676 bp sequence revealed the presence of two introns. The identities of the deduced amino acid sequence to the corresponding Saccharomyces cerevisiae and Candida albicans fragment are 65 and 63.8%, respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Minor triterpenoids of Fomes officinalis

The degraded triterpenoid, 3β,6β-dihydroxy-4,4,14α-trimethyl-Δ⁸-5α-pregnene-20-one (II) and 3-keto-dehydrosulfurenic acid (III), have been isolated from the extracts of Fomes officinalis and their structures determined.     

Les sterols de l'Ascomycete Leptosphaeria typhae

A mixture of C₂₈ and C₂₉ sterols have been isolated from Leptosphaeria typhae grown in vitro on “oat water” and characterized by GLC and MS. Mono-, di- and tri-unsaturated sterols are present in the extracts of fungi cultivated both in the dark and in the light but the sterol composition is different. The influence of “oat water” on sterol structure has been determined by comparison with the sterols of the same fungus grown on synthetic medium in the dark.