A thermostable intracellular lipoxygenase from Thermomyces lanuginosus was purified to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) homogeneity by ion-exchange chromatography on diethylaminoethyl (DEAE)-Sepharose, ion-exchange chromatography on carboxymethyl (CM)-Sepharose and Phenyl-Sepharose hydrophobic interaction chromatography. The molecular weight of the enzyme was estimated to be 100 kDa by SDS-PAGE. The lipoxygenase exhibited maximal activities at pH 6.0. The optimum temperature for the activity was 55 °C. The enzyme was thermostable at 50 ° with half-lives at 60 ° of 20 min and 70 ° of about 7 min. The lipoxygenase activity was completely lost by heating at 80 ° for 5 min. The lipoxygenase catalyzed the oxidation of linoleic acid into 13-L-hydroperoxy-9,11(Z,E)-octadecadienoic acid(13-HPOD) as the major product. The enzyme had an apparent Km of 8.5 μM and Vmax of 10.8 μmol mg−1 min−1 with linoleic acid as substrate.

The adhesion of conidia of Pestalotiopsis neglecta occurs in four stages in a specific manner which allows the first cell most likely to germinate to become firmly attached its substrate while leaving the other two fertile cells free to be dispersed further, thereby increasing the chance of further successful infections. The first stage of adhesion involves the mucilaginous coating acquired from the conidial matrix and appears weak. The second stage of adhesion is also relatively weak and occurs at the bases of the pedicel. The third stage occurs with the release of a fibrillar adhesive substance from along the length of the pedicel to the top of the basal cell and at times a lesser amount of fibrillar material is released from the apical appendages. The fourth stage involves the release of fibrillar material at the point of germtube emergence. The third and fourth stages provide strong attachment.

Soil samples from six sites in Provence, France, were flooded with water and baited with cellophane, specifically to obtain Rhizophlyctis rosea; all proved positive. By standardizing the cellophane addition and counting the R. rosea thalli that grew on it, derivations of thallus recovery g−1 of soil (TRG) were possible. Where aliquot soil samples for assay were small, sterilized soil leachate was used to chemically reinforce the flood water. Mean TRG was 395 for a grassland soil and 1293 following drying and removal of small stones from it. Separated leaf humus from the same dried soil had a mean TRG of 1105. Thought was given to what these figures might represent, in terms of sporangia of R. rosea present in the soil at the time of its collection. These are the first quantitative results in soil ecology for the Chytridiales.

The two forms of acid phosphatase secreted by Botrytis cinerea were purified, characterized and found to possess fundamentally different properties. The phosphate-repressible acid phosphatase was a monomer of clearly defined molecular weight (55–56 kDa), with a polypeptide component of 43 kDa. The enzyme was secreted through the hyphal apex and accumulated in the culture fluid. Its high affinity for a wide range of substrates rendered it suitable for a putative role as an extracellular phosphate-scavenging enzyme. Secretion of a constitutive acid phosphatase occurred at low levels in phosphate-enriched culture; at phosphate starvation, the activity of this enzyme was enhanced ten-fold in the culture fluid and two-fold in the cell wall. The constitutive enzyme had strikingly different properties from those of the repressible form. It consisted of a 93 kDa polypeptide which was heavily glycosylated such that the secreted protein displayed size heterogeneity of 140–200 kDa by SDS–polyacrylamide gel electrophoresis and 320–450 kDa by native Sephacryl S-300 chromatography. Irrespective of the phosphate status, most of the secreted constitutive enzyme activity was retained by the cell wall. These results were consistent with ultrastructural histochemical observations which suggested that this enzyme form was secreted by a novel pathway via the fusion of vacuoles with the plasma membrane in mature hyphal segments.

A Cylindrocladium-like hyphomycete collected on leaf litter of Celtis tala in Argentina had rDNA sequence data (ITS and LSU) that showed it resides in the Hypocreales, and is a member of the Nectriaceae, closely related to, but distinct from Cylindrocladium. A new genus, Dematiocladium and species, D. celtidis gen. sp. nov. is, therefore, introduced to accommodate this fungus. Based on morphology, it can be distinguished from other conidial hypocrealean genera with hyaline, penicillate conidiophores and cylindrical conidia by lacking stipe extensions and vesicles, and by the presence of brown to dark brown, thick-walled setae.

The taxonomy of the non-yellow species of the genus Rhizocarpon (Rhizocarpaceae, lichenized Ascomycota) occurring in the Nordic countries, with hyaline and muriform ascospores, has been revised. Rhizocarpon amphibium, R. anaperum, R. distinctum, R. furfurosum, R. lavatum, R. petraeum, R. postumum, R. reductum, R. roridulum, R. rubescens, R. subgeminatum, R. sublavatum (reported from the study area for the first time), R. subpostumum, R. suomiense, R. timdalii, and R. umbilicatum are recognized. Their morphology, anatomy, secondary chemistry, ecology, and distribution in the Nordic countries are investigated and discussed. Distribution maps and a key to the species are provided. The most important characters for separating the treated species are pruinose/epruinose thallus, number of ascospores in asci, ascospore size and number of cells per ascospore in optical view, insoluble lichen pigments of the epihymenium and the proper excipulum, and lichen substances. Seven names are lectotypified and two are neotypified.

Genetic variability was investigated in North American populations of the tree pathogenic fungi Nectria galligena and N. coccinea var. faginata. Genetic diversity was estimated by analysing RAPD and ribosomal DNA polymorphisms. The number of haplotypes was the maximum value in N. galligena (51), whereas 17 different haplotypes were detected among the 23 isolates of N. coccinea var. faginata studied. The frequency of polymorphic loci was greater in N. galligena (92%) than in N. coccinea var. faginata (35%). The estimate of genotypic diversity was a maximum in N. galligena while it represented only 59% of the maximum value for N. coccinea var. faginata. Gene diversity was also higher in the former (21%) than in the latter (6%). Moreover, four distance indexes calculated from the same genetic distance matrix gave similar results and showed that distances among isolates of N. galligena were four to nearly six times larger than distances among N. coccinea var. faginata isolates. An analysis of molecular variance based on genetic distances among haplotype frequencies confirmed that host origin (beech vs other species) was not the source of the genetic variability in N. galligena since less than 1% of the variability was attributable to the host factor. Overall, our results are consistent with the hypothesis that N. galligena is a pathogen native to North America while N. coccinea var. faginata may be a recent introduction.

Nia globospora sp. nov., a marine basidiomycete, provisionally put in the Melanogastrales, producing fruit bodies on dead culms of Spartina maritima is described. The species grew on baits that were submerged for a period of 6 months in the Mira River estuary, Portugal. Comparisons with other species of Nia are made.

Two new species of Helicoon, H. myosuroides and H. dendroides, are described and illustrated, and their characteristics are outlined in comparison with similar species. Both species belong to the ecological group of the aero-aquatic fungi and are even more specialized as they only inhabit raised bogs. Their ecological characteristics are discussed in detail.

Development of mushrooms is driven by genetic and epigenetic factors in a continuous interaction with the environment. It is assumed that each successive stage of morphogenesis depends on specific sets of signals arising at the appropriate time and place during the growth process. Morphogenetic dynamism proceeds in a time dimension through a cascade of signal-effect associations. Developmental errors may occur when such signals originate in the wrong place and/or at the wrong time. As a result various abnormalities such as ectopic tissues can develop and morphogenesis can be severely disturbed. Both endogenous genetic disturbances and exogenous factors can cause developmental errors. Lamellar dysplasia, which is a pore-like proliferation of the gills, forms an example; it may be induced experimentally. Both lamellar dysplasia and rosecomb disease of Agaricus bisporus result from endogenous genetic instability, whereas the developmental errors observed in wet bubble disease, which is caused by the infection of Mycogone perniciosa, originate from an exogenous factor. Morphogenesis normally leads to a symmetrical form of primordia of A. bisporus. Asymmetry is very frequently associated with an underlying pathological situation. Defining exact criteria of and sharp borderlines between normal and abnormal development seems infeasible. Fungi may readily tolerate morphogenetic imprecision. In this report, various macro- and microscopic features of normal and pathological development are illustrated; the dilemma of normal versus abnormal fruit body development has been discussed.

Morphogenesis is not simply a matter of playing out a predefined genetic programme. Expression of developmentally important genes is epigenetic and place- and time-dependent relying on previously-formed tissue structures. Most differentiated hyphal cells require reinforcement of their differentiation ‘instructions’. This reinforcement is part of the context (chemical, electrical and structural/mechanical environment) within which they normally develop. Key words at each stage of development in fungi are: competence, induction and change. Fungal morphogenesis is compartmentalized into a collection of ‘sub-routines’ which are distinct genetically and physiologically. Flexibility in expression of developmental sub-routines illustrates that tolerance of imprecision is an important attribute of fungal morphogenesis.

Coniochaeta rhopalochaeta sp. nov. was isolated from decorticated wood of Bulnesia retama in Argentina. It is distinguished principally by the ascomata with mace-like capitate setae. C. scatigena is first recorded for Argentina. A key to the seven known Argentine species of Coniochaeta is provided. Asci of these species were studied with fluorescence microscopy; size of the fluorescent apical ring could be a useful taxonomic character.

A taxonomic review and revision of the dematiaceous hyphomycete genus Acrogenospora is presented. Species in this genus produce acrogenous, solitary, nonseptate conidia from mononematous, simple conidiophores, with multiple percurrent proliferations. Acrogenospora altissima comb. nov. and A. megalospora comb. nov. are proposed for the anamorphic states of two Farlowiella species. A. ovalia and A. subprolata spp. nov. are described from submerged wood in Hong Kong. They differ from other Acrogenospora species in shape, colour, and size of their conidia. A taxonomic key to species in the genus is provided.

Thirty-one isolates of the form genera Acremonium and Cephalosoporium were screened for their ability to excrete enzymes capable of degrading β-glucans. Most produced both (1 → 3)- and (1 → 6)-β-glucanases together, although the yields varied with carbon source used. Surprisingly, higher yields of (1 → 3)-β-glucanases were often seen from isolates grown on pustulan, a (1 → 6)-β-glucan which is not hydrolysed by these enzymes. Lower enzyme yields were generally obtained with glucose than with either laminarin, a (1 → 3)-β-glucan or pustulan as carbon sources, suggesting regulation of synthesis by either catabolite repression and/or induction. However, a few isolates, most notably Cephalosporium sp. OXF C13 and Acremonium strictum appeared to have some constitutive-β-glucanase activity. Most of the isolates screened were only very weakly cellulolytic against carboxymethyl cellulose or filter paper as substrates.

The genetic relatedness among 29 collections belonging to 20 of the most common species of genus Amanita in the Iberian Peninsula have been studied by means of restriction analysis of the amplified ITS1-5.8S-ITS2 region of rDNA. Sixty restriction fragments were considered for the analysis. The main conclusion is that this technique could be useful to identify and characterize isolates from Amanita species. Although ARDRA did not show an appropriate level of discrimination to unambiguously infer phylogenetic relationships at or below the section level, some general trends could be outlined when the different haplotypes generated were compared by means of neighbour joining analysis. Thus, members from the same sections were frequently grouped together.

Discolouration due to senescence differs from blotch-related discolouration, which might indicate differential mechanisms being operational. In samples infected with bacteria or with a partially purified toxin extract, a higher degradation of total tyrosinase than in senescening mushrooms was found. Simultaneously, the active tyrosinase was increasing resulting in an increase in percentage of active tyrosinase. Phenolic substrates of the active tyrosinase were being oxidized, proportionally to the damage detectable on the mushroom cap. γ-Glutaminyl-3,4-dihydroxybenzene was degraded first, followed by γ-glutaminyl-4-hydroxybenzene and later tyrosine. The amount of melanin that was synthesized was larger than the sum of oxidation of the phenols measured. Principal Component Analysis explained 84% of the variance in symptoms, and it demonstrated the phenol oxidation and active tyrosinase level as the most important parameters for the browning induced by bacteria or a tolaasin preparation treatment.

Three polypeptides with manganese superoxide dismutase (MnSOD) activity were found in mycelium, zoospores and germinated cysts of Phytophthora nicotianae. Their relative molecular weights in non-denaturing gels were approximately 34.5, 36 and 50 kDa. No evidence for the presence of either iron or copper/zinc SODs was detected at any of the developmental stages examined. The level of activity of the MnSOD polypeptides was similar in mycelia and spores. Degenerate PCR was used to amplify partial genes of two different MnSODs, designated PnMnSOD1 and PnMnSOD2, from P. nicotianae. Southern blot analysis indicated that there are two PnMnSOD1 genes in the P. nicotianae genome. Full length sequence was obtained for one of these genes, PnMnSOD1a, from a P. nicotianae bacterial artificial chromosome (BAC) library. RNA blots probed with PnMnSOD1 showed similar levels of expression in vegetative and sporulating hyphae, lower levels in germinated cysts and no detectable expression in zoospores. PnMnSOD1a had 96%, 97% and 99% amino acid identity with homologous genes from P. ramorum, P. infestans and P. sojae, respectively. The second gene cloned from P. nicotianae, PnMnSOD2, had only 38% amino acid identity with PnMnSOD1a and was homologous to MnSODs that possessed an N-terminal mitochondrial targeting sequence in Phytophthora species and other eukaryotes. Southern blots indicated that there is one copy of PnMnSOD2 in the P. nicotianae genome. PnMnSOD2 was expressed at similar levels in mycelia and germinated cysts but PnMnSOD2 transcripts were not detectable in zoospores.

Linear mycelial aggregates (rhizomorphs) produced by the squamulose lichens Toninia opuntioides, Squamarina cartilaginea, Lecanora rhizinata, and Acarospora scotica were examined by transmission electron microscopy (TEM). Cytological features typical of lichenized mycobionts were present, including concentric bodies and plasmalemma invaginations. Some septa in rhizomorphs of S. cartilaginea and A. scotica appeared to be multipored. Septal pores were usually plugged by an electron-dense structure. Intrahyphal hyphae were common to abundant in the rhizomorphs of all four species examined. The wall of the invasive hypha was continuous with inner wall layers of the cell of origin. Contacts between adjacent hyphae involved wall dissolution and formation of new wall layers, leading to anastomosis and/or possibly to intrahyphal invasion. Differentiation of an outer layer of collapsed cells in rhizomorphs of Squamarina cartilaginea and of extremely thick-walled cells Lecanora rhizinata was evident, but no anatomical specialization comparable to the ‘vessel hyphae’ of non-lichen linear mycelial organs was observed. Enlarged spheroid or ovoid cells with dense cytoplasm, numerous mitochondria and lipid reserves occurred in short chains in rhizomorphs of Acarospora scotica; infrequently, similar cells were observed singly in those of Squamarina cartilaginea. These cells were reminiscent in shape of certain types of oil hyphae found in endolithic lichens, although often the lipid content of the enlarged cells was not particularly pronounced.

Four ascomycete species with brown 1-septate ascospores with wall ornamentation were identified from palms in Ecuador and Brunei. Asci were long cylindrical, relatively thick-walled, bitunicate with non-fissitunicate dehiscence, and the hamathecium was composed of trabeculae. These fungi are referred to Roussoëlla, and are described and illustrated in this paper, including two new species. A key to accepted species of Roussoëlla is provided.

Leptographium species are common inhabitants of fresh conifer logs and lumber that are known for their ability to cause blue-stain and, in some cases, their association with disease. L. procerum has been associated with a root disease although controversy surrounds its role in tree death. During the course of the past two decades, a relatively large number of isolates tentatively identified as L. procerum have been collected in various parts of the world. Some of these display morphological characters unlike those of L. procerum s. str. and this has prompted us to re-examine them. Four groups of morphologically distinct isolates were identified, of which L. procerum s. str. represented one. The remaining isolates of Leptographium are newly described as L. alethinum, L. pityophilum and L. euphyes spp. nov.