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At least 811 records · Page 45Linked to original sources
PubMed2002

Rapid detection of lytic antimicrobial activity against yeast and filamentous fungi.

A rapid method for assessing the lytic activity of antimicrobial agents against yeast and fungi has been developed. The assay is based on the release of the intracellular enzyme, maltase (alpha-glucosidase). The released maltase activity was measured colorimetrically by the production of p-nitrophenol from p-nitrophenyl-alpha-D-glucopyranoside (PNPG). The lytic activity of different antimicrobial compounds was measured against yeast cells or germinating spores of filamentous fungi. Lytic anti-yeast activity could be detected within 20 min incubation at 30 degrees C against Saccharomyces cerevisiae, Candida albicans, and Cryptococcus neoformans. Lytic anti-fungal activity appeared after 2 h of incubation at 30 degrees C against germinating spores of Aspergillus niger and Botrytis cinerea. Whole cells of either yeast or fungi did not hydrolyze sufficient PNPG within 3 h at 30 degrees C to yield a detectable color change. Lytic activity of enzymes (e.g., Lyticase), antibiotics (e.g., Amphotericin B), and an antibiotic-producing strain of bacteria were detected using the assay. The anti-yeast assay has been adapted to a 96-well microtiter format. Both assays provided a rapid, sensitive, and reproducible detection of lytic anti-yeast and anti-fungal activity.

Antifungal Agents↗
PubMed1999

Detection of siderophore production from several fungi and bacteria by a modification of chrome azurol S (CAS) agar plate assay.

A well-known and widely used method for detection of siderophore production by microorganisms in solid medium is the universal chrome azurol S (CAS)-agar plate assay. However, the high toxicity of CAS-blue agar medium caused by the presence of a detergent impedes its utilization with many varieties of fungi and Gram-positive bacteria. To solve this problem, a modification of the CAS-agar plate assay was made by incorporating the CAS-blue dye in a medium with no contact with the microorganisms tested. Half of each plate used in our experiments was filled with the most appropriate culture medium for each type of microorganism and the other half with CAS-blue agar. This modification allowed us to study several strains of fungi (basidiomycetes, deuteromycetes, ascomycetes and zygomycetes) and bacteria (Gram positive and negative), some of them appearing for the first time in the literature. All the microorganisms grew properly and reacted in different manners to the CAS assay. Some strains of wood-decaying basidiomycetes (mainly white-rot fungi) and Aspergillus species produced the fastest color-change reactions in the CAS-blue agar. This modified method could facilitate optimization of culture conditions, since both CAS-blue agar and growth medium were prepared and added in the Petri plate separately.

Agar↗
PubMed1997

Incidence and detection of thermotolerant and thermophilic fungi from maize with particular reference to Thermoascus species.

A number of thermotolerant and thermophilic fungi were isolated from shipments of food-aid grain, and from large bag stacks of maize stored in sub-Saharan Africa. Thermotolerant fungi included Aspergillus candidus, A. fumigatus, A. flavus and Paecilomyces varioti; thermophilic fungi included Thermomyces lanuginosus, Rhizomucor pusillus, Thermoascus aurantiacus and T. crustaceous. Temperature profiles for Thermoascus spp. indicated that isolates of T. aurantiacus grew up to 60 degrees C, and T. crustaceous to 55 degrees C, whereas Paecilomyces could not grow above 50 degrees C. Thermoascus species isolated from grains conformed to published morphological descriptions. Problems associated with the detection and interpretation of fungal spoilage in relation to heat-damaged grain are discussed.

Ascomycota↗
PubMed1992

Occurrence of keratinolytic fungi and related dermatophytes in soils in Cairo, Egypt.

120 soil samples collected from various sites of Cairo were processed for the isolation of keratinophilic fungi by "ToKaVa" hair baiting technique. 22 species belonging to 6 genera were isolated viz.: Chrysosporium tropicum, C. indicum, C. keratinophilum, C. queenslandicum, C. merdarium, C. anamorph of Arthroderma curreyi, C. pannicola, C. lobatum, C. anamorph of Renispora flavissima, C. pseudomerdarium, Microascus mangini, Malbranchea gypsea, Ml. State of Uncicarpus reesii, Ml. State of Coccidioides immitis, Microsporum gypseum, Mr. distortum Mr. audouinii, Mr. fulvum, Trichophyton mentagrophytes, T. terrestre, T. verrucosum and Epidermophyton floccosum. The frequency of occurrence of the isolated fungi was determined. Microsporum gypseum, Chrysosporium tropicum and Chrysosporium indicum were the most frequent species recovered from soil. Most species of keratinophilic fungi were isolated from university, public garden and zoo garden. The distribution of the isolates are discussed.

Arthrodermataceae↗
PubMed1999

Biological control of nematode parasites of livestock in Fiji: screening of fresh dung of small ruminants for the presence of nematophagous fungi.

Approximately 2500 faecal samples were collected per rectum from sheep and goats from 26 farms located on four of the Fijian islands where most of the small ruminants in this country are raised. The purpose was to screen these samples to isolate nematode-trapping fungi that had been acquired by these animals during the course of their feeding and which had remained viable following passage through their gastrointestinal tract. From these samples, 23 examples of nematophagous fungi were noted in the initial appraisal, from which 12 pure isolates (all of the genus Arthrobotrys) were made. A number factors emerged from this work which may have restricted the opportunities in which nematophagous fungi were detected, or isolated.

Animals↗
PubMed1978

Production of protein by fungi from agricultural wastes. VI. Quality of the protein formed in Rhizoctonia melongina, Pleurotus ostreatus, and Coprinus aratus.

The amino acid content of the three fungi, viz., Rhizoctonia melongina, Pleurotus ostreatus, and Coprinus aratus, grown in liquid media (JAUHRI and SEN 1978d) containing agricultural wastes (sugarcane bagasse for the former two and wheat straw for the latter), were analysed qualitatively. Amino acid fraction of the three fungi, determined through paper chromatography, contained all the 8 essential amino acids in addition to 9 odd amino acids, except in the case of Rhizoctonia melongina in which the essential amino acid lysine was lacking. The possibilities for mass production and the use of these three fungi in dietetics are further discussed in this paper.

Agaricales↗
PubMed2000

Microsporidia: accumulating molecular evidence that a group of amitochondriate and suspectedly primitive eukaryotes are just curious fungi.

Microsporidia are obligate intracellular parasites that have long been considered to be primitive eukaryotes, both on the basis of morphological features and on the basis of molecular, mainly ribosomal RNA-based, phylogenies. However, accumulating sequence data and the use of more sophisticated tree construction methods now seem to suggest that microsporidia share a common origin with fungi and are therefore most probably just curious fungi. In this paper, we describe the current views on the phylogenetic position of the microsporidia and present additional evidence for a close relationship between fungi and microsporidia on the basis of reanalyzed ribosomal RNA data. In this respect, the importance of incorporating detailed knowledge of the substitution pattern of sequences into phylogenetic methods is discussed.

Animals↗
PubMed2000

Evaluation of a water-extracted pharmamedia agar medium for the culture of fungi.

The purpose of this investigation was to determine the value of a water-extracted Pharmamedia agar medium for the culture of fungi. The growth of the fungi on this medium was compared to that on Sabouraud brain heart infusion agar. The Pharmamedia extract agar supported the growth of the 42 filamentous and yeast or yeast-like fungi that were examined. The medium was relatively clear to easily permit observation of the diagnostic microscopic and macroscopic architecture of the organisms. The Pharmamedia extract agar also permitted the conversion of the mold-to-yeast phase with Blastomyces dermatitides and Penicillium marneffei. This investigation supports the use of Pharmamedia as a culture medium for the clinical microbiology laboratory. Its relative simplicity of preparation and effective use as a culture medium, as well as a conversion medium, emphasizes its useful application for clinical mycology.

Agar↗
PubMed2000

Response of Eucalyptus tereticornis to inoculation with indigenous AM fungi in a semiarid alfisol achieved with different concentrations of available soil P.

Eucalyptus tereticornis was grown in a green house in a low phosphorus (0.67 ppm Olsen's P) soil (Typic Haplustalf) inoculated with mixed indigenous arbuscular mycorrhizal (AM) fungi. Soil was amended to achieve P levels of 10, 20, 25, 30 and 40 ppm to evaluate the growth response and dependence of E. tereticornis to inoculation with AM fungi. A positive response to mycorrhizal inoculation was evident at the first two levels of soil P, i.e., at 0.67 and 10 ppm but not at the higher levels of soil P. Dry matter yield of inoculated plants beyond 20 ppm soil P was similar or even less compared to their uninoculated counterparts. Inoculated plants produced maximum dry matter (root and shoot) at 10 ppm soil P, whereas uninoculated plants did not produce until the level reached 20 ppm. The percentage root length colonized by AM fungi decreased from 31% to 3% as the concentration of P increased beyond 10 ppm soil P. Higher levels of soil P depressed the AM colonization significantly. Inoculated plants had higher shoot P and N contents compared to their uninoculated counterparts at all levels of soil P. However, at the first two lower levels of soil P, inoculated plants showed significantly higher shoot P and N contents over their respective uninoculated counterparts. The increasing shoot P accumulation beyond 10 ppm did not enhance dry matter yields. Inoculated plants had lower values of phosphorus utilization efficiency (PUE) and nitrogen utilization efficiency (NUE) at all levels of soil P except at the unamended level (0.67 ppm) where the inoculated plants showed higher values of NUE compared to uninoculated control plants. Taking dry matter yield into consideration, Eucalyptus plants were found to be highly dependent on 10 ppm of soil P for maximum dry matter production. Any further amendment of P to soil was not beneficial neither for AM symbiosis nor plant growth.

Desert Climate↗
PubMed2002

Microbial detoxification of waste rubber material by wood-rotting fungi.

The extensive use of rubber products, mainly tires, and the difficulties to recycle those products, has resulted in world wide environmental problems. Microbial devulcanisation is a promising way to increase the recycling of rubber materials. One obstacle is that several microorganisms tested for devulcanisation are sensitive to rubber additives. A way to overcome this might be to detoxify the rubber material with fungi prior to the devulcanisation. In this study, 15 species of white-rot and brown-rot fungi have been screened with regard to their capacity to degrade an aromatic model compound in the presence of ground waste tire rubber. The most effective fungus, Resinicium bicolor, was used for detoxification of rubber material. Increase in growth of the desulfurising bacterium Thiobacillus ferrooxidans in presence of the rubber treated with Resinicium bicolor compared to untreated rubber demonstrated that detoxification with fungi is possible.

Anthraquinones↗
PubMed2003

Removal of phenanthrene from soil by co-cultures of bacteria and fungi pregrown on sugarcane bagasse pith.

Sixteen co-cultures composed of four bacteria and four fungi grown on sugarcane bagasse pith were tested for phenanthrene degradation in soil. The four bacteria were identified as Pseudomonas aeruginose, Ralstonia pickettii, Pseudomonas sp. and Pseudomonas cepacea. The four fungi were identified as: Penicillium sp., Trichoderma viride, Alternaria tenuis and Aspergillus terrus that were previously isolated from different hydrocarbon-contaminated soils. Fungi had a statistically significant positive (0.0001<p) effect on phenanthrene removal, that ranged from 35% to 50% and bacteria removed the compound by an order of 20%. Co-cultures B. cepacea-Penicillium sp., R. pickettii-Penicillium sp., and P. aeruginose-Penicillium sp. exhibited synergism for phenanthrene removal, reaching 72.84+/-3.85%, 73.61+/-6.38% and 69.47+/-4.91%; in 18 days, respectively.

Bacteria↗
PubMed2002

The fitness of filamentous fungi.

Fitness is a common currency in comparative biology. Without data on fitness, hypotheses about the adaptive significance of phenotypes or basic mechanisms of evolution, for example natural selection, remain speculative. Experiments with fungi can address questions specific to fungi or questions with a broader significance. Fungi can challenge the generality of fundamental evolutionary principles, yet there are no standard measures of fungal fitness. We argue that focusing on a single aspect of a complex life cycle, or a single measure of fitness (e.g. the number of asexual spores) is appropriate. Choosing which aspect of fitness to measure can be facilitated by an understanding of how fitness measures are correlated. Choices can also be based on the ecology of a species, for example whether a fungus is semelparous and reproduces once, or iteroparous and reproduces multiple times.

Biological Evolution↗
PubMed2002

Predicting the distribution, conservation, and functions of SNAREs and related proteins in fungi.

Hyphal tip growth, the hallmark of the fungi, requires highly polarized and localized exocytosis, but how this requirement is met is unknown. Members of conserved protein families called SNAREs and Rabs mediate vesicle trafficking and fusion at virtually every step of the intracellular pathway in all examined eukaryotes. We have searched the available nearly complete fungal genomes, established the presence or absence of members of the SNARE and Rab families in these genomes, and predicted their evolutionary relationships to one another. Comparisons with the extensively studied Saccharomyces cerevisiae indicate that, in general, most of the members of these families (including those involved in mediating exocytosis) are conserved. The presence of exceptional SNAREs and Rabs in some fungi that are not conserved in S. cerevisiae may be indicative of specialized steps that occur in these fungi. The implications of these findings for current tip growth models are discussed.

Amino Acid Sequence↗
PubMed1992

In vivo passage through calves of nematophagous fungi selected for biocontrol of parasitic nematodes.

The experiment was designed to test the survival and performance of stress selected nematophagous fungi after passage through the gastro-intestinal tract of cattle. Ruminating calves were fed daily with a fixed amount of fungal material grown on barley grains. The excreted dung was collected on days four and five after the start of the feeding experiment. Barley grains were washed out of the excreted dung and incoculated on water-agar plates. After incubation for one week, nine of ten fungal isolates were re-isolated from these plates. The predatory capacity of the fungi in the excreted faeces was tested in a dung pat bioassay and a faecal culture system. In the dung pat bioassay, two fungi of the genus Arthrobotrys and six of the genus Duddingtonia reduced the development of Ostertagia ostertagi third stage larvae by 85% (61%-93%), compared to the number of larvae developed from fungus-free control pats. In seven out of these eight isolates, the reduction of larvae in the faecal cultures was 92% (76%-99%).

Animals↗
PubMed1999

Predatory behaviour of trapping fungi against srf mutants of Caenorhabditis elegans and different plant and animal parasitic nematodes.

The initial infection process of nematode-trapping fungi is based on an interaction between the trapping structure of the fungus and the surface of the nematode cuticle. A bioassay was designed to investigate the predatory response of several isolates of nematode-trapping fungi against 3 mutants of Caenorhabditis elegans (AT6, AT10 and CL261), which have been reported to differ in the reaction of their cuticle to antibodies and lectins. The bioassay was also applied to infective larvae of animal (Haemonchus contortus, Teladorsagia (Ostertagia) circumcincta and Trichostrongylus axei) and plant (Meloidogyne spp.) parasitic nematodes. Differences in trapping ability were most marked in the first 24 h, and were density dependent. Although the isolate of Arthrobotrys responded very rapidly in the first 24 h, Duddingtonia flagrans was generally the most effective isolate and Monacrosporium responded relatively poorly throughout all experiments. All the fungi tested trapped the srf mutants of C. elegans more efficiently than the wild type, and there were differences between the different srf mutants of C. elegans. Differences in trapping ability were also observed between different isolates of D. flagrans; similarly, differences in trapping behaviour were observed not only amongst the different species of plant-parasitic nematodes, but also between the sheathed and exsheathed larvae of the animal-parasitic nematodes.

Animal Population Groups↗
PubMed2004

Fungal secondary metabolites as inhibitors of infection-related morphogenesis in phytopathogenic fungi.

The life-cycle of many plant-pathogenic fungi, especially those infecting aerial plant organs, contains several specific developmental stages. If these are sufficiently distinct in their physiology from vegetative hyphal growth, they present potential targets for non-fungitoxic plant protectants. The present review identifies such targets especially in the pre-penetration stages of the infection cycle of Magnaporthe grisea and other fungi infecting from air-borne spores. Examples of non-toxic natural products with activity against spore germination, attachment, appressorium formation, appressorium maturation and penetration of the host surface are given. In contrast, no substances selectively active against in planta growth or sporulation appear to be known. The selective activity of numerous secondary metabolites against specific infection stages without accompanying toxicity against vegetatively growing hyphae indicates a direction for the development of future natural product-derived fungicides which are more easily degraded in the environment and possess fewer non-target effects. Such substances are produced by many saprotrophic and endophytic fungi in pure culture. The paucity of data on the production of biologically active substances in natural situations limits the interpretation of their ecophysiological significance for the producer.

Antifungal Agents↗
PubMed2004

Ecology and molecular characterization of dark septate fungi from roots, living stems, coarse and fine woody debris.

The aim of the present work was to determine the identity and molecular relationships between 127 strains of dark septate (DS) fungi isolated from healthy root tips, decayed coarse roots, live healthy-looking stems, coarse (stumps, snags and logs) and fine (tree branches and tops) woody debris in temperate-boreal forests in Sweden and Lithuania. Sequence analysis of ITS rDNA was used to identify the fungi. In a neighbour-joining similarity tree, all sequences were grouped into five distinct clusters. Within each of these, ITS rDNA sequence variation consisted of 2-18 nucleotides, corresponding to 1-3% of their total length. The four least variable clusters were supported with high bootstrap values of 86-100%. Comparisons with the sequences in the GenBank database showed that all our strains had a 95-100% homology with identified Phialocephala species, and they were thus assigned to this genus. The representatives of two clusters were identified, as P. fortinii and P. dimorphospora. The representatives of three remaining clusters were defined as Phialocephala sp. 35, Phialocephala sp. 6 and Phialocephala sp. 18. Within each of these clusters, ITS rDNA sequence uniformity was higher than that observed within P. fortinii and P. dimorphospora. Consequently, their clusters were most discrete, supported with bootstrap values of 100%. Genetic variation in the five distinguished Phialocephala species and their possible ecological roles are discussed. Phialocephala sp. 6 was confined to healthy root tips of conifers. P. dimorphospora was only associated with dead woody tissue of P. abies. P. fortinii, Phialocephala sp. 18 and sp. 35 were isolated from both dead and living conifers and Betula pendula. In conclusion, the present study revealed the ability of fungi from the genus Phialocephala to colonise and persist in live and dead trees under strikingly different ecological conditions.

Base Sequence↗
PubMed2005

Microcolonial rock inhabiting fungi and lichen photobionts: evidence for mutualistic interactions.

On nutrient-poor rock surfaces, yeast-like black fungi (also called microcolonial fungi, MCF) may derive organic carbon either from the atmosphere or from interactions with other rock-inhabiting microorganisms. Interactions between free-living rock inhabiting heterotrophic fungi and phototrophic algae were investigated using axenic cultures. Five typical MCF strains were incubated with pure cultures of four lichen photobionts isolated from lichens growing in similar locations. After 2-12 months of combined cultivation, the fungal and algal colonies developed an overlapping structure involving both partners. Microscopic, histological and ultrastructural methods were used to investigate the changes that occur after prolonged contact. Histological analysis demonstrated changes in the spatial organisation of mixed colonies when in contact with each other. The branching of fungal hyphae was more pronounced in the vicinity of algal cells, thus increasing the potential contact surface. Photobiont cells were not changed in size, but a reduction of sporulation could be observed in some Trebouxia strains. Close cell wall contacts between fungal and algal cells were formed and mucilage accumulated at the contact places. The ability of MCF to form associations with potential photobionts present on rock surfaces was thus demonstrated for pure cultures in vitro.

Chlorophyta↗