Mycoflora and trichothecene toxins of paddy grains from Egypt

120 species and 38 genera were collected from 64 samples of paddy grains on glucose- and cellulose-Czapek's agar at 28 °C. The total count of glycophilic and cellulose-decomposing fungi fluctuated between 216–29760; and 124–11320 colonies/g paddy grains on the two media, respectively.On glucose agar, the most common species were Aspergillus niger, A. flavus, A. sydowi, A. terreus, A. fumigatus, A. ochraceus, Penicillium chrysogenum, P. corylophilum, Fusarium oxysporum, Alternaria alternata, Cladosporium cladosporioides, Trichoderma viride and Mucor racemosus.On cellulose agar with pH 5.5 & 8.0, the most prevalent fungi were Stachybotrys chartarum, S. bisybi, Aspergillus niger, A. flavus, Fusarium oxysporum, Alternaria alternata, Drechslera sativus and Acremonium strictum.Extracts from 64 paddy samples were tested against brine shrimp larvae (Artemis salina). Of these 9 displayed varying degrees of toxicity. Trichothecene-toxins were detected in the extracts of three paddy samples only. Diacetoxyscirpenol and T-2 toxin were detected in two samples and only T-2 toxin in the other.     

In vitro cytotoxicity of melleolide antibiotics: structural and mechanistic aspects

Melleolide sesquiterpene aryl esters are secondary products of the mushroom genus Armillaria. We compared the cytotoxicity of eleven melleolides—five thereof are new natural products—against four human cancer cell lines. Armillaridin, 4-O-methylarmillaridin, and dehydroarmillylorsellinate were most active, at IC₅₀ = 3.0, 4.1 and 5.0 μM, respectively, against Jurkat T cells for the former two compounds, and K-562 cells for the latter. Dehydroarmillylorsellinate did not inhibit respiration and RNA-synthesis of K-562 cells at 5 μM. However, replication of DNA dropped to 35% after 120 min at this concentration, and translational activity also decreased.     

蒜头果内生真菌次生代谢产物抑制人类致病菌活性的研究

蒜头果是我国特有的单种属稀有树种,为了进一步开发利用蒜头果树皮内生真菌的抗菌活性化合物,该研究对来自蒜头果的植物内生真菌(白黄笋顶孢霉、哈茨木霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌、朱黄青霉、Xenoacremonium recifei、Xylaria feejeensis)进行液体培养,10 d后回收培养液并用乙酸乙酯萃取获得初提物,采用抑菌圈法检测蒜头果内生真菌初提物抑菌活性,同时测定了最低抑菌浓度(MIC)。结果表明:白黄笋顶孢霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌均有抑菌活性,大棘黑团孢、斑污拟盘多毛孢、淡紫紫孢菌的初提物均对缓慢芽孢杆菌、无乳链球菌和藤黄微球菌有明显抗菌活性,最低抑菌浓度在1.562 5~6.25 mg·m L~(-1)之间。这说明蒜头果树皮内生真菌的次生代谢产物具有抗菌活性,各内生真菌次生代谢产物的抗菌效果不同。     

Chitinolytic activity of filamentous fungi

The chitinolytic activity of nine species of filamentous fungi, classified with seven genera (specifically, Aspergillus, Penicillium, Trichoderma, Paecilomyces, Sporotrichum, Beaueria, and Mucor), was studied. When cultured in liquid medium containing 1% crystalline chitin, all fungi produced extracellular chitosans with activity varying from 0.2 U/mg protein (Sporotrichum olivaceum, Mucor sp., etc.) to 4.0-4.2 U/mg protein (Trichoderma lignorum, Aspergillus niger).     

Antifungal activity of some plant extracts on some pathogenic fungi

The inhibitory activity of five plant extracts viz. Artemisia absinthium L., Rumex obtusifolius L., Taraxacum officinale Weber ex Wiggers, Plantago lanceolata L. and Malva sylvestris L. were evaluated against the mycelial growth of three fungi Alternaria alternata (Fr.) Keissler, Penicillium expansum Link ex Thom. and Mucor piriformis Fisher that cause rot diseases in fruits and vegetables resulting in low yield and quality of fruits and vegetables. Results revealed that all the concentrations of plant extracts brought about significant inhibition in the mycelial growth of these pathogenic fungi. However, the highest concentration caused maximum inhibition in the mycelial growth followed by lower concentrations of plant extracts. The extract of A. absinthium leaves at highest concentration (S) proved highly effective in inhibiting the mycelial growth of all these pathogenic fungi followed by other plant extracts. These plants thus may have potential as the new natural fungicide for management of fungal rot diseases.     

Chitinolytic Activity of Filamentous Fungi

The chitinolytic activity of nine species of filamentous fungi, classified with seven genera (specifically, Aspergillus, Penicillium, Trichoderma, Paecilomyces, Sporotrichum, Beaueria, and Mucor), was studied. When cultured in liquid medium containing 1% crystalline chitin, all fungi produced extracellular chitosans with activity varying from 0.2 U/mg protein (Sporotrichum olivaceum, Mucorsp., etc.) to 4.0–4.2 U/mg protein (Trichoderma lignorum, Aspergillus niger).     

Extracellular enzymatic activity profiles in fungi isolated from oil-rich environments

About 34 wild fungal species associated with edible oil mill wastes were isolated by the serial dilution technique. Methods for rapid screening of fungal species against production of extracellular enzymes such as amylase, protease, cellulase, and lipase are reported. Among all the species, Aspergillus versicolor exhibited high amlylolytic and gelatinolytic activity, whereas Penicillium citrinum showed only high amylolytic activity. Maximum cellulolytic activity was recorded for Absidia corymbifera, As. niger, Cunninghamella echinulata, Curvularia lunata, Fusarium solani, Mucor racemosus, Paecilomyces variotii, and Syncephalastrum racemosum. The fungal species Ab. corymbifera, As. fumigatus, As. japonicus, As. nidulans, As. terreus, Cun. verticillata, Cur. pallescens, F. oxysporum, Geotrichum candidum, M. racemosus, Pe. citrinum, Pe. frequentans, Rhizopus stolonifer, and Trichoderma viride exhibited maximum lipase activity. This study confirms the isolated fungi present on a wide range of substrates in the ambient environment, and these results could provide basic data for further investigations on fungal extracellular enzymes.First two authors equally contributed to this work     

Morphological characteristics of natural strains of certain species of basidiomycetes and biological analysis of antimicrobial activity under submerged cultural conditions

Twenty-one strains belonging to 18 species of basidiomycetes from different ecological groups of fungi were isolated from natural sources. Light and electron microscopy was used to determine the morphological properties of the cultures, which confirmed their classification as basidiomycetes and facilitated their identification in monocultures. The capacity of the fungal strains for biosynthesis of antibiotics was determined by one- or two-stage cultivation on seven nutrient media. It was established that, under submerged cultivation, antimicrobial substances were formed by 13 strains (81.25%) of 12 fungal species (Armillaria sp., Coprinus comatus, Flammulina velutipes, Hypsizygus ulmarius, Lentinus tigrinus, Lycoperdon pyriforme, Macrolepiota procera, Panellus serotinus, Pholiota aurivella, Pholiota lenta, Rhodocollybia maculate, and Sparassis crispa). The antibiotics formed were efficacious against bacterial test strains, including the methicillin-resistant strain Staphylococcus aureus (MRSA) and the strain Leuconostoc mesenteroides VKPM B-4177 that is resistant to the glycopeptide antibiotics. No antibiotic activity was revealed against fungal test cultures (Aspergillus niger INA 00760 and Saccharomyces cerevisiae RIA 259).     

Detection of 3-nitropropionic acid and cytotoxicity inMucor circinelloides

Mucorales are regarded as the aetiological agents of Mucormycosis. Their capabilities to produce mycotoxins are not profoundly investigated, in contrast to those of the fungi from the generaPenicillium, Aspergillus, orFusarium. The aim of this study was to isolate and identify fungi of the order Mucorales and investigate mycotoxins production. Twelve samples of visibly moulded grass silage and eight samples of damaged whole crop maize silage were analysed. Malt extract agar plates were used for sub cultivation. Three fungal species of the order Mucorales were isolated from grass silage, which were identified by their macro-and micro-morphology asAbsidia corymbifera, Mucor circinelloides andRhizopus stolonifer. The cytotoxicity ofMucor circinelloides extract was analysed using the cytotoxicity test (MTT assay) and the result, showed a low cytotoxicity. Additionally extracts fromAbsidia corymbifera, Mucor circinelloides andRhizopus stolonifer were tested for mycotoxin-production using an LC/MS/MS-based multimycotoxin method. 3-nitropropionic acid was detected in the culture extract ofMucor circinelloides. Presented at the 30^th Mykotoxin Workshop Utrecht, Netherlands, April 28–30, 2008.     

Molecular characterization and antimicrobial activity of endophytic fungi from coffee plants

Endophytic filamentous fungi from coffee plants (Coffea arabica and C. robusta) deposited in the Brazilian Collection of Environmental and Industrial Microorganisms (CBMAI) were characterized taxonomically by using molecular tools and investigated concerning their antimicrobial activity against different human pathogenic bacteria. Thirty-seven out of 39 CBMAI strains investigated were identified to at least at genus level by ITS and rDNA D1/D2 sequencing and phylogenetic analyses. Bioactivity screening of fungal extracts against Salmonella choleraesuis (CBMAI 484), Staphylococcus aureus (CBMAI 485), Pseudomonas aeruginosa (CBMAI 489) and against four different Escherichia coli serotypes showed that 17 fungi inhibited at least one of the bacteria studied. The endophytic fungi Trichoderma harzianum (CBMAI 43), Guignardia sp. (CBMAI 69) and Phomopsis sp. (CBMAI 164) inhibited from four to five bacterial species, while five fungi were active against all pathogenic bacteria tested and were identified as Aspergillus versicolor (CBMAI 46), Fusarium oxysporum (CBMAI 53), Glomerella sp. (CBMAI 63) and Cladosporium spp. (CBMAI 64 and CBMAI 66). The Minimal Inhibitory Concentration (MIC) for the fungus extracts varied from 0.025 to 1.0 mg ml⁻¹, demonstrating antimicrobial potential of some of these fungi.     

Screening pentachlorophenol degradation ability by environmental fungal strains belonging to the phyla Ascomycota and Zygomycota

Pentachlorophenol (PCP) bioremediation by the fungal strains amongst the cork-colonising community has not yet been analysed. In this paper, the co- and direct metabolism of PCP by each of the 17 fungal species selected from this community were studied. Using hierarchical data analysis, the isolates were ranked by their PCP bioremediation potential. Fifteen isolates were able to degrade PCP under co-metabolic conditions, and surprisingly Chrysonilia sitophila, Trichoderma longibrachiatum, Mucor plumbeus, Penicillium janczewskii and P. glandicola were able to directly metabolise PCP, leading to its complete depletion from media. PCP degradation intermediates are preliminarily discussed. Data emphasise the significance of these fungi to have an interesting potential to be used in PCP bioremediation processes.     

A viscometric study of the biodegradation of photographic gelatin by fungi isolated from cinematographic films

The biodegradation of photographic gelatin grade (Bloom 225) material was studied by viscometry in aqueous solution (at 37 °C, 6.67% w/w) using filamentous fungi isolated and identified from cinematographic film stored in different Spanish archives. From viscosity data, different variables such as molecular weight and chain scission were calculated. To ensure initial spore suspension concentration was standardized for all the biodegradation experiments, a correlation between transmittance at 530 nm of fungal spore suspensions and the corresponding cytometric determination of populations was established for all the fungal strains studied in this work. The bioassay experiments were carried out at 25 and 4 °C using an initial concentration of fungi of 4.5×10⁵ conidia/mL except in the case of the genus Alternaria, where the concentration was 10 times lower. The fungal strains were three species of Aspergillus, i.e., A .ustus, A. nidulans var. nidulans, A. versicolor, seven Penicillium chrysogenum strains, and Cladosporium cladosporioides, Alternaria alternata, Mucor racemosus, Phoma glomerata, and Trichoderma longibrachiatum. All were gelatinase positive. Through the viscosity decay profiles with bioassay-time and the corresponding calculated chain scission, the relative quantitative gelatinase efficiency of these fungi has been evaluated.     

The Effect of Felling on the Occurrence of Microfungi Stimulatory to Armillaria Rhizomorph Formation in Thin Roots of Quercus robur

Eight fungal assemblages were isolated from thin branch roots (0.5–1 mm diameter) of living oak trees (Quercus robur) and their stumps 2 years after felling. The roots were serially washed or surface‐sterilized with ethanol and hypochlorite. The thin roots were inhabited by fungi that are stimulants of Armillaria rhizomorphs as found previously in thick roots (0.5–1 cm diameter). However, unlike thick roots, the densities of the fungi in serially washed roots were significantly less in stump roots than in living roots. Among the most common ‘stimulants’, the frequencies of Cylindrocarpon didymum, Mortierella gracilis, Mor. microspora var. macrocystis, Mycelium radicis atrovirens, Nectria grammicospora, Pseudogymnoascus roseus and Sporothrix schenckii were usually significantly greater in stump roots than in living roots, while the frequencies of Chrysosporium merdarium, Cy. destructans, Mor. hygrophila, Penicillium adametzii, Pe. citrinum, Pe. daleae, Pe. janczewskii and Pe. spinulosum were usually significantly less in stump roots. The frequency of Trichoderma viride was less in the stump roots. Serial washing of roots was more effective than chemical surface‐sterilization in the detection of Armillaria rhizomorph ‘stimulants’. The significance of these findings in the ecology and risk assessment of Armillaria in plantations is discussed.     

Mycobiota and molecular detection of Aspergillus flavus and A. parasiticus aflatoxin contamination of Strawberry (Fragaria ananassa Duch.) fruits

Strawberry fungi were isolated from fresh fruits and juice on the two types of media (Sabouraud dextrose agar, SDA and potato-dextrose agar, PDA) at 28 °C. Nineteen fungal species belong to 12 genera were isolated from fruits and juice on both isolation media. The most common fungal genera and species were Aspergillus flavus, A. niger, Mucor racemosus, Neurospora crassa, Penicillium chrysogenum, Rhizopus stolonifer and Trichoderma harzianum. Twenty A. flavus and A. parasitics isolates were assayed for their abilities to produce aflatoxins. The concentration of aflatoxins ranged between 25.8–75.2 and 23.6–71.1 ng/ml at 350 and 365 nm, respectively. Among A. flavus and A. parasiticus strains tested, aflatoxin B contributed 30–60% of total isolates. However, G type contributed 85–90%. The R_f values of B₁, B₂, G₁ and G₂ were 0.79, 0.61, 0.44 and 0.32, respectively. High-performance liquid chromatography analysis of extracts revealed the presence of aflatoxins with variable levels.     

Keratinolytic and keratinophilic fungi in the soils of Papua New Guinea

A study was made of soil samples collected during an expedition to the Highlands of Papua New Guinea. Fungi were isolated from the samples by the method of hair baiting (To-Ka-Va). Of the 33 species isolated, about half showed keratinolytic activity. Such activity is previously unreported for Mucor hiemalis f. hiemalis, Myrothecium roridum, Paecilomyces carneus, P. marquandii, Penicillium brevicompactum, Rhinocladiella mansonii and Verticillium lecanii. The species most active keratinolytically were Chrysosporium an. Arthroderma cuniculi, C. an. A. curreyi, C. indicum, Myceliophthora vellerea and Trichophyton ajelloi. The spectrum of fungi with keratinolytic activity isolated from the different sites differed considerably according to the frequency of use by man, heaviest use being correlated with greatest activity. The pH of the soil (varying from 5.8–7.5) had little influence on the type of such fungi isolated.     

Separation of Fungal Propagules by Partition in Aqueous Polymer Two-Phase Systems

Conidia of Penicillium chrysogenum and Penicillium frequentans and sporangiospores of Rhizopus rhizopodiformis, Rhizomucor pusillus, and Mucor racemosus were subjected to partition in aqueous polymer two-phase systems. The partition behavior differed drastically between the conidia of the two Penicillium species and the sporangiospores of the three species of phycomycetes. This difference in partition behavior can be used for purification of fungi belonging to different taxonomical groups. P. frequentans was completely separated from M. racemosus by two extractions, whereas four extractions were needed to purify M. racemosus. This method was used on an air sample from a locality where wood fuel chips are handled. The conidia of the fungi Trichoderma viride and Rhizopus rhizopodiformis were removed completely by only two extractions.     

Insoluble hydrophobin complexes in the walls of Schizophyllum commune and other filamentous fungi

Two closely related cysteine-rich hydrophobic proteins, Sc3p and Sc4p, of the basidiomycete Schizophyllum commune are developmentally regulated and associated with the walls of aerial hyphae and fruit-body hyphae. They are present in the walls as hot-SDS-insoluble complexes which can be extracted with formic acid. The hydrophobins can then be dissociated by oxidation with performic acid. However, extraction of the walls with trifluoroacetic acid results in both solubilization and dissociation of the hydrophobin complexes into monomers. This suggests that non-covalent interactions are responsible for formation of these insoluble complexes. Carboxymethylation with iodoacetic acid only occurred after reduction with DTT indicating all cysteines in the monomeric hydrophobins involved in intramolecular disulfide bridges. Abundant proteins with similar properties were found in walls from all other filamentous fungi tested, including the basidiomycetes Pleurotus ostreatus, Coprinus cinereus, Agaricus bisporus, and Phanerochaete chrysosporium, the ascomycetes Aspergillus nidulans, Neurospora crassa, and Penicillium chrysogenum, and the zygomycete Mucor mucedo.     

Inhibitory effect of Torilis anthriscus on growth of microorganisms

Antibacterial and antifungal activities of aqueous, ethanol and ethyl acetate extract of Torilis anthriscus (L.) Gmel. (Apiaceae) were tested in vitro against ten species of bacteria and five of fungi. Antimicrobial properties were determined by disk diffusion and broth tube dilution method. In the minimum inhibitory concentrations (MICs), the ethanol extract showed the highest activity, followed by the ethyl acetate extract and the aqueous extract against bacterial species, while the extracts were inactive against the tested fungi species. The most active extract was chosen to examine the effects of its combinations with commercial antibiotics by checkerboard method. The obtained results showed that the interactions between ethanol extract/streptomycin and ethanol extract/chloramphenicol were additive and indifferent against the tested human-pathogenic bacteria. Synergism and antagonism were not observed.     

Keratinophilic fungi from soil of Brittany,France

The Present work reports the study of the distribution of keratinophilic fungi isolated from 39 samples of soil collected in Brittany, France. Keratinophilic fungi were isolated from 35 (92.3%) of the samples studied. The most frequently found species wereFusarium moniliforme, Penicillium viridicatum and an unidentified species ofAcremonium. The other fungi isolated were members of the generaChrysosporium, Gliocladium, Mucor, Trichoderma andTrichophyton.     

Interaction dynamics between saprobic lignicolous fungi and Armillaria in controlled environments: Exploring the potential for competitive exclusion of Armillaria on peach

Armillaria root rot, caused by Armillaria tabescens and Armillaria mellea, is a major cause of premature tree death in peach orchards in the southeastern United States. The root systems of infected trees can become entirely colonized by Armillaria, serving as an inoculum source for adjacent trees and providing massive inoculum levels in replant situations. If dead or dying trees could be colonized by an effective competitor of Armillaria before their removal, the extent of root colonization by the pathogen could be reduced, thus decreasing the threat to adjacent trees and/or subsequent plantings. Interactions between five species of saprobic lignicolous fungi (Ganoderma lucidum, Hypholoma fasciculare, Phanerochaete velutina, Schizophyllum commune, and Xylaria hypoxylon) and the two Armillaria species were examined in controlled conditions to provide proof of concept for competitive exclusion of Armillaria from peach roots. On agar-coated glass slides, all five potential antagonists induced detrimental reactions in >58% of the Armillaria hyphae observed, with the majority resulting in hyphal swelling or granulation. On poplar wood blocks, all antagonists consistently either overgrew Armillaria colonies or—in the case of S. commune—engaged in deadlock reactions; in all cases, the viability of Armillaria colonies was reduced to <30% of that of unchallenged controls. When inoculated simultaneously onto opposite ends of peach root segments, all antagonists consistently reduced growth and viability of Armillaria on and under the bark, whereby reduction of pathogen growth underneath the bark, Armillaria’s primary ecological niche, was most pronounced for G. lucidum, S. commune, and X. hypoxylon. When root segments were allowed to be colonized entirely by Armillaria before being inoculated with the antagonists, the latter were able to overgrow the pathogen on the root surface but unable to pre-empt it from underneath the bark. In summary,G. lucidum, S. commune, and X. hypoxylon caused strong hyphal and mycelial interference reactions and the most pronounced reductions in growth of Armillaria above and below the bark, indicating that they would be the most promising candidates for field-scale evaluations to restrict colonization of dead or dying peach trees by Armillaria in the orchard.