Acid phosphatase production by 12 Hebeloma strains was usually derepressed when inorganic phosphorus in the growth medium was limited, but appeared to be constitutive in some strains. At low temperatures ([les ]12°) arctic strains produced more extracellular and wall-bound acid phosphatase, yet grew more slowly than the temperate strains. We suggest that low growth rates in arctic strains may be a physiological response to cold whereby resources are diverted into carbohydrate accumulation for cryoprotection. At near freezing temperatures, increased extracellular phosphatase production may compensate for a loss of enzyme activity at low temperature and serve to hydrolyse organic phosphorus in frozen soil over winter.

The suitability of random amplified polymorphic DNA for identification of Pythium aphanidermatum was investigated. Three oligoprimers were selected after testing three isolates of P. aphanidermatum and one isolate of P. ultimum with a total of 40 primers. The selected 10-mer primers were used with 20 isolates of P. aphanidermatum, four isolates of P. deliense, two isolates of P. ultimum, two isolates of P. irregulare and one isolate of P. paroecandrum. Most of the P. aphanidermatum isolates (13 of 20), were obtained from samples of Cucumis sativus, or water from cucumber greenhouses. The three selected primers gave identical fingerprints for 18 of the 20 P. aphanidermatum isolates, including all the isolates from cucumbers. Two of the primers gave fingerprints that could be used to differentiate between isolates of the Pythium species studied. The banding pattern of P. aphanidermatum given by the third primer could not easily be distinguished from the fingerprint of P. deliense. However, when used in conjunction with the other two primers, the third primer can be used to verify the identity of P. aphanidermatum.

The relation between the pattern of fumonisin production and the mating population and mating type of Fusarium isolates from maize in Argentina at different maturity stages has been evaluated. Fifty-one isolates of Fusarium species belonging to the Liseola section were identified to mating population and tested for their ability to produce fumonisins (FB1, FB2 and FB3). Only mating populations associated with maize, A (Fusarium moniliforme, 23 isolates), D (F. proliferatum, 24 isolates) and E (F. subglutinans, 4 isolates) were found. All but two isolates of populations A and D produced, when grown on maize substrate, high levels of fumonisins ranging from 0·01 to 3·99 mg g−1 (mean 2·00 mg g−1 and 1·69 mg g−1, respectively), whereas isolates of population E yielded less than 0·02 mg g−1 (mean 0·01 mg g−1). Five isolates of F. proliferatum, all belonging to mating type D−, produced more FB2, than FB1, which is consistent with finding a relatively large amount of FB2 (0·01 mg g−1; FB2/FB1=2·27) in one of the maize samples from which these isolates were obtained. Amounts of FB3 were similar to FB2 in cultures of mating population A (mean FB3/FB2=0·89), but much lower than FB2 in cultures of mating population D (mean FB3/FB2=0·21).

Rotiferophthora ellipsospora and R. japonica spp. nov., are described as endoparasites of bdelloid rotifers, forming large dictyochlamydospores and small infection conidia. Verticillium bactrosporum was found in association with a new host species of bdelloid rotifer and was cultured for the first time: resting spores were formed in culture.

Eleven cultures representing eight genera of five families of Loculoascomycetes were obtained from ATCC and IMI. Partial 18S and 28S nuclear ribosomal DNA (rDNA) were amplified using PCR and sequenced. About 1100 bps of 18S rDNA (NS1/NS4 region) and 459 bps of 28S rDNA (F63/R635 region) for each taxon were subject to phylogenetic analysis using parsimony. The reconstructed phylogenetic trees supported the separation of two monophyletic groups, containing the type genera of the Leptosphaeriaceae and the Pleosporaceae, respectively. The members of the Leptosphaeriaceae (sensu Barr) consisted of the paraphyletic clade in the phylogenetic trees. The members of the Pleosporaceae (sensu Barr) plus Pyrenophora trichostoma formed a monophyletic clade. The results generally supported the separation of the Leptosphaeriaceae from Pleosporaceae and the placement of P. trichostoma, and Comoclathris baccata in the Pleosporaceae. The taxonomic position of Pleospora betae, whose coelomycetous anamorph is more closely related to Leptosphaeriaceae, was not well resolved because of low bootstrap values and decay indices. Leptosphaeria bicolor, whose ascospore morphology is not congeneric with the type of the genus, L. doliolum, does not belong to Leptosphaeria based on the 18S sequence data. The taxonomic disposition of Lewia, Pyrenophora, and Comoclathris based on the phylogenetic analyses are discussed.

Four new species of Pseudocercospora are described, illustrated and compared with allied taxa. These are P. asiatica or Glochidion lanceolarum, P. melochiigena on Melochia corchorifolia, P. operculinae on Operculina terpethum and P. trewiae-nodiflorae on Trewia nodiflora.

Isolates of Pithomyces chartarum obtained from pasture samples originating from Australia, Brazil, New Zealand and Uruguay were evaluated for their ability to produce sporidesmin. Only isolates that produced enough spores to confirm the presence or absence of sporidesmin were evaluated. Samples from the countries examined gave proportions of sporidesmin-producing isolates of: Australia, 67% of 207 isolates; Brazil, 2% of 51 isolates; New Zealand, 86% of 391 isolates and Uruguay, 28% of 182 isolates. Considerable variations in the ability to produce sporidesmin were found, not only between countries but between samples taken from the same country.

An endo-DNase with single strand nicking activity from the bean pathogen, F. solani f. sp. phaseoli has been previously reported to induce the expression of defence genes in peas. Culture filtrates of the potato pathogen, Colletotrichum coccodes, also contain a single strand nicking endo-DNase (CCN). This nuclease has a molecular weight of ∼27 kDa, an isoelectric point of pH 7·8, optimal catalytic activity at pH 5–6 and is stable at temperatures below 50°C. CCN activity increases are observed with addition of cation cofactors, favouring Mn2+>Co2+>Ca2+> Na+>Zn2+. CCN is inhibited by aurintricarboxylic acid, a nuclease inhibitor. The point of CCN cleavage on the DNA molecule is between the 5′-phosphate and the 3′-hydroxyl. CCN also possesses RNase activity. Although the C. coccodes culture filtrate can induce the expression of disease resistance response genes and phytoalexin production in pea tisue, this inductive activity does not co-purify with the CCN DNase activity through the Sephacel G-75 purification step, and thus CCN applied singly does not serve as a signal for initiating the host defence reponses. Because CCN degrades both DNA and RNA, it is more probably a nutrient scavenging enzyme.

Orphella catalaunica and O. helicospora spp. nov. both from the hindgut of stonefly (Leuctra) nymphs from Spain, are described and illustrated. They are compared with the other species of the genus. Orphella haysii is reported for the first time in Europe. The generic description of Orphella is emended to accommodate the new characters described for the new species. A dichotomous key for separating the species is provided.

A coelomycetous genus, Pseudophragmotrichum gen. nov., with the type species P. cubense sp. nov., is described from dead culms of Oncidium lucidum from Cuba. It differs from other coelomycete genera in having intercalary conidiogenous cells, thallic conidiogenesis and flattened conidia.

Asterina hopiicola, Asterinella pterigotae, Echidnodella memecyli and Lembosia humboltiae are described and illustrated as new species.

Random Amplified Microsatellite (RAMS) markers were used to detect variation among Phlebiopsis gigantea isolates from seven European countries. The scoring of 26 bands revealed five markers common to all isolates and 21 variable markers, of which six occurred in only one strain. A considerable amount of variation was observed among the progeny isolates of single strains. The analysis of variable markers resulted in 75 different banding patterns among the 86 isolates studied. The high degree of polymorphism and heterozygosity observed in RAMS markers suggests that the amount of genetic variation within this fungus is considerable. The equal distribution of markers in strains from different locations and the lack of country-specific markers suggests that genetic differentiation among the populations is low. The lack of distinct groups of similar banding patterns supports the idea of P. gigantea being a true biological species consisting of a single intersterility group.

Recent studies suggest that the antifungal agents itraconazole, bifonazole, and ketoconazole affect calcium-mediated signal transduction in Trichophyton rubrum. We have now examined the effects of azole-antifungal agents on cell membrane function in T. rubrum, by analysing the effects of itraconazole, bifonazole, ketoconazole, and lanoconazole on ionomycin-induced changes in intracellular calcium concentration ([Ca2+]i). Addition of 1 μm ionomycin to the culture medium produced a persistent increase in [Ca2+]i. While treatment with 1·5–15 nM of lanoconazole or bifonazole for 24 h did not affect this ionomycin-induced increase in [Ca2+]i, 30 nM of these agents resulted in a transient increase in [Ca2+]i rather than the usual sustained increase in [Ca2+]i. This transient ionomycin-induced increase in [Ca2+]i was also observed after treatment with only 1·5 and 3 nM of ketoconazole or itraconazole. Incubation in the presence of lanoconazole or bifonazole at [ges ]150 nM, and ketoconazole or itraconazole at [ges ]15 nM inhibited both the persistent and transient ionomycin-induced increase in [Ca2+]i. On the basis of these findings, it is suggested that azole antifungal agents disturb membrane function in T. rubrum, and that one manifestation of this effect is the disruption of the ionomycin-induced increase in [Ca2+]i. We report that the ionomycin-induced increase in [Ca2+]i is more sensitive to low concentrations of ketoconazole and itraconazole compared to bifonazole and lanoconazole.

Variation in Gremmeniella abietina var. abietina was studied in three stands of Scots pine in northern Finland and in the Kola Peninsula. Eighty-four isolates of large- and small-tree types of G. abietina var. abietina (LTT and STT, respectively) were identified on the basis of tentative characteristics (spore morphology, disease type and host size), fatty acid and sterol profiles (FAST), and random amplified microsatellite technique (RAMS). Both LTT and STT occurred in all three stands. In general, the classifications obtained using the three methods agreed with one another, although a few contradicting results were observed. Variation in fatty acids and sterols in G. abietina var. abietina was rather low, although the amounts of some individual extractives showed statistically significant differences between the stands. All pathogenic and asymptotic G. abietina var. abietina isolates originating from branches located at heights above the annual snow cover were identified as LTT based on RAMS, but some were grouped to STT according to their FAST profiles. Both STT and LTT were detected among the isolates obtained from seedlings according to both FAST and RAMS. In addition, in two cases RAMS markers thought to be STT- or LTT-specific were found in the same isolate. The results presented here suggest that LTT of G. abietina var. abietina caused the devastating epidemics on pines in the first-thinning stage or middle age similar to pines in this study reported in northern Finland and in the Kola Peninsula during the 1980s.

Olpidium paradoxum sp. nov. was found to attack adult loricate rotifers and their eggs in a sample of pond water in Japan. The fungus produced zoosporangia inside the host from which exit tubes of variable length grew to the outside environment. Pyriform zoospores with a single long posterior flagellum were released from the sporangia.

Two types of genetic markers, vegetative compatibility and RAPD, were evaluated for their ability to assess genetic variation among 38 isolates of the entomopathogenic fungus, Paecilomyces fumosoroseus. Both markers revealed significant polymorphisms. Nitrate non-utilizing mutants were generated from chlorate-containing media and used as forcing markers to observe heterokaryon formation and determine vegetative compatibility. Nineteen separate vegetative compatibility groups (VCGs) were identified, only seven having at least two members and 12 represented by single isolates. No correlation was observed between VCG and either insect host or geographic origin. Nine RAPD primers produced 365 unique fragments and could distinguish three different phenetic groups. RAPD profiles conclusively showed that strains within some VCGs were genetically unrelated, indicating that these strains were not clonal in origin. The large number of VCGs suggests that formation of heterokaryons and possible genetic exchange are uncommon. DNA fingerprinting with RAPD-PCR provides high resolution of genotype distribution and could be useful in tracking the fate of biocontrol agents released into the environment.

A total of 479 samples of nests or feeding sites of 38 species of Australian termite were plated onto a medium selective for isolation of Metarhizium spp. Sixty-seven samples were positive for Metarhizium spp. and a total of 97 isolates of M. anisopliae were obtained. Very few isolates were obtained directly from infected termites. Most isolates were obtained from nest-mound material from eastern Australia. Termite-associated material from the two common mound-building species of termite, Nasutitermes exitiosus and Coptotermes lacteus, provided 75 of the isolates. Similar material from 26 species of termites revealed no Metarhizium. A detailed study of two sites found that some of the Metarhizium isolates found in nest-mound material, including also some M. flavoviride and M. album, were of morphological types also present in adjacent soil. The DNA of isolates from mounds and the adjacent soil were compared using RAPDs and sequence analysis of the ITS region of the nuclear rDNA and the same types were found from both sources. The possible role of the fungus in termite ecology is discussed and it is thought most likely that Metarhizium is only opportunistically a pathogen of termites. Thus, isolates obtained from termite nest material are probably there because of the incorporation of soil into termite nests.

Sixteen highly branched (colonial) mutants of Fusarium graminearum A3/5 were isolated at the end of 11 Quorn® myco-protein production fermentations. These ranged from the highly branched C134-3 to the sparsely branched C145, which was similar to A3/5 in liquid culture. Although allelic complementation was observed to occur between some of the mutants, heterokaryon analysis revealed that all the highly branched mutants belonged to a single complementation group. Mixed cultures of A3/5 and six of the colonial mutants were grown in glucose-, ammonium-, magnesium- and sulphate-limited chemostat culture. One mutant (C153) had a selective advantage over A3/5 in all nutrient limitations tested; four mutants (C134-1, C134-3, C137-1, and C135) had a selective advantage over A3/5 in all except one nutrient limitation; and one mutant (C139) had a selective advantage over A3/5 in magnesium-limited chemostat culture only. Four mutants (C134-3, C139-1, C153 and C135) had a selective advantage over A3/5 when the dilution rate was increased above the critical dilution rate (0·22 h−1) and nutrients were present in excess. These results suggest that the growth conditions in the Quorn® production plant (which is operated as a glucose-stat) favour mutations that confer general growth rate advantages, but these mutations may result in growth disadvantages when nutrient limitations are imposed. As all of the mutations appear to occur in one gene or gene cluster, the differing patterns of selective advantage/disadvantage for the six mutants studied suggests that regulatory genes may also be involved or that different sites of mutation can lead to a variety of pleiotropic effects.

Linocarpon smilacis sp. nov., Nitschkia phaeospora sp. nov., Ophiodothella cyclobalanopsidis sp. nov., Physalospora palmicola sp. nov., Physalospora smilacis sp. nov. and Tubeufia miscanthi sp. nov. from Taiwan are described and illustrated by microphotographs. Each is compared with related taxa.

Female flies (Phorbia phrenione) cross fertilize Epichloë typhina via a specific behaviour in which they transfer spores among self-incompatible fungi. Flies ingest spores while visiting fungi for egg laying. Only 11% of stromata lacking P. phrenione eggs produced perithecia and these perithecia covered an average of only 8% of the stromatal surfaces. In contrast, 71% of stromata that possessed fly eggs produced perithecia, covering 54% of the stromatal surfaces. Immediately following oviposition, flies stereotypically drag their abdomen across the fungus in a spiral pattern while excreting faeces. Transfer of fly faeces to unfertilized stromata resulted in cross fertilization. We observed spiralling patterns of perithecial development on fungal surfaces, signifying the behaviour of the fly results in cross fertilization of the fungus. This is the first documentation of active fertilization in an insect-fungus mutualism.