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PubMed1993

Mycelial elongation and sporulation of two fungi on amended media in light or dark.

Botrytis allii and Collectotrichum dematium are onion pathogens which can infect in the field and cause decay in storage. Some phenolics can hinder development of these fungi, but the effect of cytokinins is not clear. Cytokinins (kinetin or 6-benzyladenine) or phenolics (caffeic or chlorogenic acids) were added to agar at concentrations of 0 to 10(-3) M. Cultures were continuously irradiated with fluorescent light or maintained in the dark for 6 days. On unamended media, final mycelial elongation was 45 or 17.8 mm and sporulation was 28 or 10.6 x 10(4) spores/ml for Botrytis and Colletotrichum, respectively. For Botrytis, mycelial elongation was slightly (5%) but significantly increased and sporulation increased by 21% by incubation on phenolics as compared to cytokinins. Mycelial extension of Colletotrichum was not affected by amendment. Sporulation of Colletotrichum on kinetin was 16 to 28% greater than on the other amendments. As amendments concentration increased elongation of mycelia of both fungi decreased. Sporulation of Botrytis increased by 60% as amendment concentration increased from 0 to 10(-5) M and then decreased 25% at 10(-3) M. As amendment concentration increased from 0 to 10(-3) M, sporulation of Colletotrichum increased by 45%. Incubation in light increased mycelial extension 3 to 17% for Botrytis and Colletotrichum respectively, and sporulation was increased approximately 78% for both fungi. These compounds do not appear to inhibit development of these Botrytis or Colletotrichum species in culture.

Culture Media↗
PubMed1981

Coprophilous fungi of the horse.

A total of 1267 microfungi, including 35 Myxomycetes, were recorded from the fecal samples of the 60 horses; of these 395 were found on 20 saddle-horse feces, 363 on 20 race-horses and 509 on 20 working horses. Eighty two species representing 53 genera were recorded; of these 7 were Zygomycetes, 18 Ascomycetes, 1 Basidiomycetes and 25 Fungi Imperfecti: 2 Myxomycetes. Common coprophilous fungi are in decreasing order Pilobolus kleinii, Saccobolus depauperatus, Mucor hiemalis, Lasiobolus ciliatus, Podospora curvula, Petriella guttulata, M. circinelloides, Coprinus radiatus, Dictyostelium mucoroides, Sordaria fimicola, C. miser, C. stercorariusm, Acremonium sp., Coprotus granuliformis, Graphium putredinis, Iodophanus carneus, Chaetomium murorum, Podospora communis, P. inaequalis, P. setosa, Saccobolus versicolor and Cladosporium cucumerinum. Species of Myrothecium verrucaria, Actinomucor elegans, Kernia nitida, Spiculostilbella dendritica and Mucor parvispora were found exclusively in working-horses feces. Badhamia sp., Anixiopsis stercoraria, Echinobotryum state of D. stemonitis, Geotrichum candidum and Oidiodendron sp. were found only in saddle-horses feces. Chlamidomyces palmarum, Philocopra sp. were found exclusively in race-horses feces. Notes on infrequent or interesting fungi include Thamnostylum piriforme, Phialocephala dimorphospora, Rhopalomyces elegans and Spiculostilbella dendritica.

Animals↗
PubMed1995

Nickel resistance mechanisms in yeasts and other fungi.

This review describes nickel toxicity and nickel resistance mechanisms in fungi. Nickel toxicity in fungi is influenced by environmental factors such as pH, temperature and the existence of organic matter and other ions. We describe resistance mechanisms in nickel-resistant mutants of yeasts and filamentous fungi which were obtained by exposure to a mutagen or by successive culture in media containing increasing concentrations of nickel ion. Nickel resistance may involve: (1) inactivation of nickel toxicity by the production of extracellular nickel-chelating substances such as glutathione; (2) reduced nickel accumulation, probably by modification of a magnesium transport system; (3) sequestration of nickel into a vacuole associated with free histidine and involving Ni-insensitivity of vacuolar membrane H(+)-ATPase.

Drug Resistance, Microbial↗
PubMed1992

Detoxification of polycyclic aromatic hydrocarbons by fungi.

The polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous environmental pollutants, many of which are acutely toxic, mutagenic, or carcinogenic. A diverse group of fungi, including Aspergillus ochraceus, Cunninghamella elegans, Phanerochaete chrysosporium, Saccharomyces cerevisiae, and Syncephalastrum racemosum, have the ability to oxidize PAHs. The PAHs anthracene, benz[a]anthracene, benzo[a]pyrene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene, as well as several methyl-, nitro-, and fluoro-substituted PAHs, are metabolized by one or more of these fungi. Unsubstituted PAHs are oxidized initially to arene oxides, trans-dihydrodiols, phenols, quinones, and tetralones. Phenols and trans-dihydrodiols may be further metabolized, and thus detoxified, by conjugation with sulfate, glucuronic acid, glucose, or xylose. Although dihydrodiol epoxides and other mutagenic and carcinogenic compounds have been detected as minor fungal metabolites of a few PAHs, most transformations performed by fungi reduce the mutagenicity and thus detoxify the PAHs.

Biodegradation, Environmental↗
PubMed1995

Detection of pathogenic fungi in human blood by the polymerase chain reaction.

The ability of the polymerase chain reaction (PCR) to detect pathogenic fungi in human blood was investigated. A DNA fragment of about 300 bp from the 18S rDNA, highly conserved in all fungi, was amplified with target DNA from 18 different species of fungi commonly isolated from clinical samples. The presence of PCR products was confirmed by hybridization with a fluorescein-labelled internal probe (21-mer). The PCR assay described is sensitive enough to detect 125 fg of purified Candida albicans DNA and 10 to 100 yeast cells per millilitre of blood.

Base Sequence↗
PubMed1995

Dermatophytes and other keratinophilic fungi causing ringworm of horses.

From 60 horses showing skin lesions, 42% were positive for fungal infection. Horses less than 2-year old were more susceptible to this infection. Fourteen species belonging to nine genera of keratinophilic and cycloheximide-resistant fungi were recovered from collected specimens. Trichophyton was the dominant genus of which T. equinum was the most common. This species proved to be the main causative agent of ringworm in horses. In addition to dermatophytes, many species of the isolated fungi were keratinophilic. The presence of such fungi on hairs and skin of horses may create an opportunity for them under special circumstances to become invasive to the skin or hair and thus cause primary or secondary infection of the animals.

Animals↗
PubMed1998

Studies on toxigenic fungi in roasted foodstuff (salted seed) and halotolerant activity of emodin-producing Aspergillus wentii.

Commercial roasted salted peanuts (3% NaCl), popcorn (1% NaCl), summer-squash (9% NaCl), sunflower (3% NaCl) and wild-melon (3% NaCl) seeds are polluted with fungi, mostly Aspergillus flavus, A. niger, Penicillium chrysogenum, P. corylophilum and Rhizopus stolonifer. Contamination of popcorn with the fungi is about 10 times higher than in the other foods. These fungi, common also on unsalted seeds, are significantly inhibited in seeds (30% moisture content) treated with 9-21% NaCl. The halotolerant A. wentii represents the main fungus recovered from seeds treated by 15-21% NaCl. 9% NaCl stimulated emodin production by A. wentii on peanut and citrinin production by P. chrysogenum on popcorn and sunflower. Aflatoxin, citrinin and emodin production on popcorn persisted up to 15% NaCl. Popcorn is thus strongly susceptible to fungal invasion and toxin pollution. The halotolerance of A. wentii was confirmed by its strong permanent growth in liquid medium at up to 15% NaCl. At 3% NaCl the mycelial growth and nitrogen content increased while the level of emodin and lipid production decreased. CO2 evolution strongly increased at 9-15% NaCl as a characteristic of A. wentii salt tolerance. Emodin inhibited seed viability and the inhibition dose for 50% reduction (LD50) was 65 mg/L for popcorn and 45 mg/L for sunflower.

Aspergillus↗
PubMed1990

Keratinophilic fungi and other moulds associated with air-dust particles from Egypt.

One-hundred and eleven species and three species varieties belonging to 39 genera were collected from 50 dust samples on the five media used at 28 degrees C. Using the hair-baiting technique with horse hair, 10 species of Chrysosporium were isolated: C. asperatum, C. state of Arthroderma tuberculatum, C. indicum, C. inops, C. keratinophilum, C. merdarium, C. pannorum, C. queenslandicum, C. tropicum and C. xerophilum. True dermatophytes were isolated: Trichophyton verrucosum and Trichophyton sp. Also, numerous fungi tolerating high levels of cycloheximide were encountered, such as members of Acremonium, Aspergillus and Penicillium. On plates of glucose or cellulose Czapek-Dox agar (free from sucrose) the most frequent fungi were: Alternaria alternata, Aspergillus flavus, A. flavus var. columnaris, A. fumigatus, A. niger, A. ochraceus, A. sydowii, A. terreus, Chaetomium globosum, Cladosporium herbarum, Emericella nidulans, Fusarium oxysporum, Mucor hiemalis, Penicillium chrysogenum, P. oxalicum, Scopulariopsis brevicaulis and Ulocladium atrum. On plates of 50% sucrose or 10 and 20% NaCl-Czapek's agar, some interesting species were frequently encountered: Eurotium amstelodami, E. chevalieri, E. halophilicum, E. montevidensis, E. repens, E. rubrum and Scopulariopsis halophilica. The isolated fungi have been tested for osmophilicity and halophilicity, they showed different rates of growth on sucrose and sodium chloride-Czapek's medium of various osmotic potential.

Air Microbiology↗
PubMed1978

Effect of volatile substances released from Origanum majorana and Ocimum basilicum on the rhizosphere and phyllosphere fungi of Phaseolus vulgaris.

Differences were found in the counts and occurrence of fungi in the phyllosphere and thizosphere of two representatives of the Lamiacea family, Origanum majorana and Ocimum basilicum, and in the phyllosphere and rhizosphere of Phaseolus vulgaris growing separately or in coenosis with O. majorana or O. basilicum. Both the volatile substances released from ground leaves of the two latter plant species and the root exudates affected considerably spore germination of isolated phylospheric and rhizospheric fungi. The results indicated a possible role of root exudates and volatile substances released from leaves in colonization of rhizosphere and/or phyllosphere by fungi, especially in associations of various plants.

Air Microbiology↗
PubMed1979

Nematocide effect of entomophilic and entomophagous fungi.

Study of nematocide effect of 48 species of entomophilic and entomophagous fungi from the class Fungi imperfecti against Panagrellus redivivus and Rhabditis oxycerca nematodes revealed a high frequency of fungi with nematocide effect. A close correlation between these two effects was disclosed by measuring the intensity of the nematocide and insecticide effect of fungal extracts.

Animals↗
PubMed2003

Decolorization and bioremediation of molasses wastewater by white-rot fungi in a semi-solid-state condition.

Molasses wastewater (vinasse; the by-product of distillation of fermented sugar) was decolorized and its chemical oxygen demand (COD) was reduced in static cultivation using the fungi Coriolus versicolor, Funalia trogii, Phanerochaete chrysosporium and Pleurotus pulmonarius ('Pleurotus sajorcaju'). The effect of cotton stalk on decolorizing and COD removing capability of four fungi was determined. In the entire concentration range tested (10-30%), wastewater was effectively decolorized by C. versicolor and F. trogii. Cotton stalk addition stimulated the decolorization activity of all fungi. The utilization of cotton stalk represents several advantages due to its function as an attachment place and as a source of nutrients; its use also reduces process costs.

Biodegradation, Environmental↗
PubMed2003

Individual and combined effect of (+/-)-alpha-hydrastine and (+/-)-beta-hydrastine on spore germination of some fungi.

(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture of both compounds was more effective than each one individually. Helminthosporium species were again the most resistant toward the mixture. The effect of both alkaloids independently on germination and development of E. pisi conidia on excised pea leaves was also shown. After pre-inoculation with (+/-)-alpha-hydrastine, the effect was more pronounced than the addition post-inoculation; maximum inhibition occurred at 200 ppm. (+/-)-beta-Hydrastine also reduced germination of conidia but was less effective than (+/-)-alpha-hydrastine. The number of primary and secondary branches of conidia and number of appressoria were not affected significantly by either compound.

Alkaloids↗
PubMed1992

Modelling the growth of filamentous fungi.

Despite the considerable industrial importance of filamentous fungi there have been very few attempts to model the complex growth process of these microorganisms. With a new generation of high performance, computerized bioreactors and new analytical techniques it is possible to obtain the necessary experimental data for setting up reliable structured models describing the growth process of filamentous fungi. It is therefore interesting to review the mathematical models described previously in the literature and the experimental data on which these models are built. Only structured models are considered due to the complex metabolism of filamentous fungi and to the natural cellular structuring of the biomass, i.e. the biomass can be divided into different cell types. In order to set up good structured models it is strictly necessary to have a detailed knowledge of the mechanisms underlying the growth process. This involves both biochemical insight and understanding of the interactions between different macromolecules and cytological organelles.

Biotechnology↗
PubMed2006

Phospholipids from some common fungi associated with damp building materials.

Methods for the analysis of fungal biomass in contaminated building materials have been limited to methods that use viable propagules as well as indicators of total biomass such as fungal glucan and ergosterol. Because of large differences in the survival times of spores, and limitations imposed by the use of agar media to assess fungal cells for the former approach, no quantitative information and poor qualitative information is obtained. The use of the biochemical indicators provides reliable quantitative information but no qualitative data. Analysis of phospholipids of various bacteria and, recently, of fungi common in outdoor air has provided both qualitative and quantitative data on their distributions in various substrates including in outdoor air samples. In this report, we provide new data on the signature lipids of some fungi common on moldy building materials. Using the LC/MS/MS analysis described, an estimate can be made of the fresh weight of fungal cells and the relative abundance of the common genera of fungi typically found on moldy materials.

Chromatography, Liquid↗
PubMed2003

Survival of filamentous fungi in hypersaline Dead Sea water.

A variety of filamentous fungi have recently been isolated from the Dead Sea (340 g/L total dissolved salts). To assess the extent to which such fungi can survive for prolonged periods in Dead Sea water, we examined the survival of both spores and mycelia in undiluted Dead Sea water and in Dead Sea water diluted to different degrees with distilled water. Mycelia of Aspergillus versicolor and Chaetomium globosum strains isolated from the Dead Sea remained viable for up to 8 weeks in undiluted Dead Sea water. Four Dead Sea isolates (A. versicolor, Eurotium herbariorum, Gymnascella marismortui, and C. globosum) retained their viability in Dead Sea water diluted to 80% during the 12 weeks of the experiment. Mycelia of all species survived for the full term of the experiment in Dead Sea water diluted to 50% and 10% of its original salinity. Comparison of the survival of Dead Sea species and closely related isolates obtained from other locations showed prolonged viability of the strains obtained from the Dead Sea. Spores of isolates obtained from the terrestrial shore of the Dead Sea generally proved less tolerant to suspension in undiluted Dead Sea water than spores of species isolated from the water column. Spores of the species isolated from the control sites had lost their viability in undiluted Dead Sea water within 12 weeks. However, with the exception of Emericella spores, which showed poor survival, a substantial fraction of the spores of Dead Sea fungal isolates remained viable for that period. The difference in survival rate between spores and mycelia of isolates of the same species points to the existence of adapted halotolerant and/or halophilic fungi in the Dead Sea.

Fungi↗
PubMed2006

The estimated impact of fungi on nutrient dynamics during decomposition of Phragmites australis leaf sheaths and stems.

Decomposition of culms (sheaths and stems) of the emergent macrophyte Phragmites australis (common reed) was followed for 16 months in the litter layer of a brackish tidal marsh along the river Scheldt (the Netherlands). Stems and leaf sheaths were separately analyzed for mass loss, litter-associated fungal biomass (ergosterol), nutrient (N and P), and cell wall polymer concentrations (cellulose and lignin). The role of fungal biomass in litter nutrient dynamics was evaluated by estimating nutrient incorporation within the living fungal mass. After 1 year of standing stem decay, substantial fungal colonization was found. This corresponded to an overall fungal biomass of 49 +/- 8.7 mg g(-1) dry mass. A vertical pattern of fungal colonization on stems in the canopy is suggested. The litter bag experiment showed that mass loss of stems was negligible during the first 6 months, whereas leaf sheaths lost almost 50% of their initial mass during that time. Exponential breakdown rates were -0.0039 +/- 0.0004 and -0.0026 +/- 0.0003 day(-1) for leaf sheaths and stems, respectively (excluding the initial lag period). In contrast to the stem tissue--which had no fungal colonization--leaf sheaths were heavily colonized by fungi (93 +/- 10 mg fungal biomass g(-1) dry mass) prior to placement in the litter layer. Once being on the sediment surface, 30% of leaf sheath's associated fungal biomass was lost, but ergosterol concentrations recovered the following months. In the stems, fungal biomass increased steadily after an initial lag period to reach a maximal biomass of about 120 mg fungal biomass g(-1) dry mass for both plant parts at the end of the experiment. Fungal colonizers are considered to contain an important fraction of nutrients within the decaying plant matter. Fungal N incorporation was estimated to be 64 +/- 13 and 102 +/- 15% of total available N pool during decomposition for leaf sheaths and stems, respectively. Fungal P incorporation was estimated to be 37 +/- 9 and 52 +/- 15% of total available P during decomposition for leaf sheaths and stems, respectively. Furthermore, within the stem tissue, fungi are suggested to be active immobilizers of nutrients from the external environment because fungi were often estimated to contain more than 100% of the original nutrient stock.

Biodegradation, Environmental↗
PubMed2002

Evaluation of white-rot fungi for detoxification and decolorization of effluents from the green olive debittering process.

Wastewater produced by the debittering process of green olives (GOW) is rich in polyphenolics and presents high chemical oxygen demand and alkalinity values. Eight white-rot fungi ( Abortiporus biennis, Dichomitus squalens, Inonotus hispidus, Irpex lacteus, Lentinus tigrinus, Panellus stipticus, Pleurotus ostreatus and Trametes hirsuta) were grown in GOW for 1 month and the reduction in total phenolics, the decolorization activity and the related enzyme activities were compared. Phenolics were efficiently reduced by P. ostreatus (52%) and A. biennis (55%), followed by P. stipticus (42%) and D. squalens (36%), but only P. ostreatus had high decolorization efficiency (49%). Laccase activity was the highest in all of the fungi, followed by manganese-independent peroxidase (MnIP). Substantial manganese peroxidase (MnP) activity was observed only in GOW treated with P. ostreatus and A. biennis, whereas lignin peroxidase (LiP) and veratryl alcohol oxidase (VAOx) activities were not detected. Early measurements of laccase activity were highly correlated ( r(2)=0.91) with the final reduction of total phenolics and could serve as an early indicator of the potential of white-rot fungi to efficiently reduce the amount of total phenolics in GOW. The presence of MnP was, however, required to achieve efficient decolorization. Phytotoxicity of GOW treated with a selected P. ostreatus strain did not decline despite large reductions of the phenolic content (76%). Similarly, in GOW treated with purified laccase from Polyporus pensitius, a reduction in total phenolics which exceeded 50% was achieved; however, it was not accompanied by a decline in phytotoxicity. These results are probably related to the formation of phenoxy radicals and quinonoids, which re-polymerize in the absence of VAOx but do not lead to polymer precipitation in the treated GOW.

Alcohol Oxidoreductases↗
PubMed2001

Patterns of evolution in Discula fungi and the origin of dogwood anthracnose in North America, studied using arbitrarily amplified and ribosomal DNA.

The anthracnose epidemic caused by exotic filamentous fungi of the genus Discula threatens the future of the prized flowering (Cornus florida L.) and Pacific (C. nuttalli Aud.) dogwoods in North America. A cross-section of fungi that cause anthracnose in broadleaf temperate trees was characterized using DNA amplification fingerprinting, sequence and secondary structure analysis of the internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA), and compatibility of hyphal anastomosis. ITS-inferred phylogenies rejected the null hypothesis of only one fungal lineage, by defining four monophyletic and well differentiated groups, corresponding to Discula sp., D. quercina, D. umbrinella and D. destructiva, with the last two species sharing a common and recent ancestor. In turn, they showed that the dogwood pathogen, D. destructiva, did not evolve directly from an indigenous population related to Discula sp. In this study, rDNA spacers that are generally considered important for protein synthesis but are selectively neutral, appeared functionally constrained and subject to selective sequence diversification. Results confirmed the high variability of D. umbrinella and the remarkable homogeneity and exotic nature of D. destructiva at the genetic level, clarified the taxonomy and phylogeny of Discula, and provided clues as to the origin and diversification of dogwood anthracnose-causing fungi.

Base Sequence↗