Recent laboratory experiments challenge the long-held view that Candida albicans is asexual and suggest that sexual recombination could occur outside the laboratory and be part of the reproductive strategy of the species. Population genetics studies, however, find little evidence, among clinical isolates, of the recombinant lineages the sexual cycle should generate. A possible explanation of these results is that the progeny of sexual recombination cannot compete with asexually propagating lineages, challenging the widely-held idea that sexual recombination is superior to asexual propagation.
Ericoid mycorrhizal fungi are symbiotically associated with the roots of members of the Ericaceae which include genera such as Calluna, Epacris, Erica, Rhododendron and Vaccinium. These ericoid mycorrhizal associations have adapted to a broad range of habitats, from mor humus soils of the northern hemisphere to sandy soils occurring in the southern hemisphere. They also play an important part in enabling plants like Calluna vulgaris (L.) Hull in the northern hemisphere to colonize mine spoils which are inhospitable environments of toxic waste for growth of most plants. The mechanisms of utilizing complex forms of nitrogen and phosphorus and providing protection against toxic metals are described. These mechanisms carried out by ericoid mycorrhizal associations enable host plants to establish in diverse habitats.
A method is described which allows the diversity of agarics in a site to be determined as an index, the Site Diversity Index (SDI). For this the individual species recorded from a site are given a score which is that of the frequency of recording class to which it has been assigned, that score increasing with increased rarity of recording in the BMS database. The methods of defining the classes of frequency of recording, the score accorded to a class, and the calculation of the SDI are described. Examples of the SDI are given for several sites in the Forest of Dean as well as for other sites and areas. Site Profiles illustrate the extent to which each of the classes has been completed. The flattening of the rate of accumulation of species is discussed. Further progress will involve the widening of the range of included species to those of other classes of basidiomycetes. The method can be used to rank sites and, in the early stages of a survey and given the meeting of two criteria, to prediction of future diversity of a site. Further use in respect of Important Fungus Areas and conservation sites is envisaged.
Since the 1950s, antifungal drug discovery has identified three classes of natural products (griseofulvin, polyenes and echinocandins) and four classes of synthetic chemicals (allylamines, azoles, flucytosine and phenylmorpho-lines) with clinical value against fungal infections. For life threatening fungal disease, the polyene amphotericin B is still a common choice despite toxic side-effects. The azoles remain the most widely used group of anti fungals active against a wide range of mycoses, benefiting from creative chemistry to boost their effectiveness. More recently, the echinocandins show great promise, with caspofungin licensed for clinical use in 2002 and two other molecules close to registration. New advances in molecular genetics afford the promise of revealing new antifungal targets, together with new agents to inhibit those targets specifically.
Ibotenic acid (α-amino-3-hydroxy-5-isoxazole acetic acid) was separated from spores and caps from Amanita muscaria by reversed phase high performance liquid chromatography and identified by flow injection analysis with mass spectrometric detection. The keto and enol tautomers of ibotenic acid were separated and their ratio of 96:4 in favour of the enol form was determined. On average the ibotenic acid content was 0.0054 ± 0.0010% of the spores and 0.017 ± 0.010% in fresh caps. Muscimol, the decarboxylated product from ibotenic acid, was neither detected in spores nor in caps. 50 nanomol of ibotenic acid, muscimol or extracts from spores or caps did not inhibit the growth of Bacillus subtilis.
The Smithsonian Institution National Museum of Natural History has unusual boxes which were made by the Inuit of Alaska in the late 1800s to hold the ashes of Phellinus igniarius basidiocarps. The fungus was burned and the ashes mixed with tobacco to give it a ‘powerful kick’. Museum collections of P. igniarius indicate that its use by Native Americans as a masticatory or for smoking purposes was widespread across North America.
Fungal pathogens are using several mechanisms to circumvent the inhibitory actions of antifungal drugs. The variety of these mechanisms was revealed in recent years by several laboratories with molecular approaches. Besides the identification of genes involved in antifungal drug resistance and the discovery of alternative pathways of resistance (i.e. biofilm formation), novel concepts in the understanding of the survival of fungal pathogen in the presence of antifungal drug (antifungal tolerance) have emerged.
During the four-year project on the Basidiomycetes of the Greater Antilles, approximately 20% of the taxa were found to be undescribed species or varieties, and some may represent new genera, families or orders.
Most nematode-trapping fungi are dependent on specific hyphal structures on or in which nematodes can be trapped mechanically or by adhesion. These structures are a prerequisite for the ability of the fungus to invade a host and are thus crucial for survival as well as virulence. The diversity of trapping structures is large and highly dependent on the environment of the fungus. Within one single species, Arthrobotrys oligospora, not only adhesive nets are formed but also so-called conidial traps, hyphal coils around hyphae of other fungi, and appressoria in the rhizosphere of agricultural crops. In this article these structures and the conditions for their development are described. Since the trapping structures influence the survival and the virulence of their producer, it is important that we know more about the molecular background of their development and function. The application of genomics to understand the function and the development of infection structures, therefore, has substantially increased the potential of A. oligospora to become a model system for fungal morphogenesis.
This article reviews the current state of knowledge about the evolutionary history of lichenized ascomycetes within an integrated system of all ascomycetes. Substantial progress has been made since molecular techniques were applied to unravel evolutionary relationships. Molecular approaches detect how often the lichen symbiosis arose, test current classification concepts, and find the proper placement for species with uncertain relationships. Uncertainties in some evolutionary hypotheses still need to be resolved by studying further genes. The currently available phylogenetic trees show a number of convergent phenotypic developments in lichenized ascomycetes. The current classification of ascomycetes is reviewed in the light of recent molecular data.
There has been interest in using environmental screening procedures for enhancing the metabolomic production profiles by fungi which are of pharmaceutical interest. This study examined two ecologically distinct species, Epicoccum nigrum and Sarophorum palmicola, in solid substrate fermentation systems over a range of water availability conditions (water activity, aW). Total secondary metabolite profiles were obtained by HPLC + diode array detection after 14 days incubation on cereal-based substrates in relation to four aW treatments. Temporal studies (24 d, E. nigrum and 18 d, S. palmicola) showed that metabolite production profiles varied markedly between the two fungi. For E. nigrum, metabolite production generally increased with reduction in aW, and was optimal in the range 0.99 – 0.97. In contrast to this, for S. palmicola, metabolite production was restricted to the highest aW level used, 0.998, and declined to zero at 0.99 aW. Statistical analysis revealed that time, aW and their interactions were significant in all cases (p < 0.001). The potential for using ecophysiological stresses for enhancing natural product discovery is discussed.
Fungi have now well and truly entered the genomic age. We currently know the complete DNA sequence for 18 fungal species and many more fungal genome sequencing projects are in progress. Whilst yeasts dominated the early genomic years, recently there has been a dramatic increase in filamentous fungal genome projects. The implications of this wealth of genetic information for mycologists worldwide is immense. In this review we summarise the background to fungal genome projects with an emphasis on the filamentous fungi. We discuss efforts to determine gene function and to compare genomes from different species. Since this is such a fast-moving field, useful web sites are listed that will enable the reader to keep up to date with developments.
Soil samples collected from glacier banks of Gulmarg, Khilanmarg, Sonamarg and Tangmarg of Kashmir valley, were examined for the prevalence of keratinophilic fungi and related dermatophytes. From the 72 positive samples (67.3 %), a total of seven genera with eleven species were isolated viz. Chrysosporium keratinophilum (3.7 %), Chrysosporium tropicum (5.6 %), Chrysosporium state of Ctenomyces serratus (11.2 %), Geomyces pannorum (2.8 %), Malbranchea sp. (0.9 %), Microsporum gypseum complex (20.6 %), Microsporum nanum (1.9 %), Microsporum van-breuseghemii (0.9 %), Trichophyton ajelloi (15 %), Trichophyton terrestre (2.8 %) and Uncinocarpus reesii (1.9 %).
The extraradical mycelium of ectomycorrhizas is comprised of a network of hyphae that may initiate rhizomorphs, sclerotia and sexual reproductive structures. The development of these structures requires photosynthates produced by host trees. In this study, the initiation and early development of Laccaria bicolor (Maire) Orton fruitbodies (basidiocarps) were studied. Seedlings of Pinus resinosa Ait. and Pinus sylvestris L. were colonized by L. bicolor, a broad host epigeous ectomycorrhizal basidiomycetous fungal species, in growth pouches. Ectomycorrhizas with an extensive extraradical mycelium formed on short roots within 7-12 days after fungal inoculum was introduced. Numerous sites of hyphal aggregation, many of which subsequently developed into basidiocarp primordia, were initiated in the extraradical mycelium. Initial changes in aggregating hyphae included swelling and branching followed by growth of hyphae perpendicular to the paper wick in growth pouches. A stipe and a pileus primordium developed but none of these basidiocarp primordia matured. Distinct regions were evident in the stipe and pileus when sections were stained by various methods. Loose hyphae at the apex and periphery of the pileus were separated by mucilage. In Petri dishes with vermiculite as the substrate, basidiocarps of Laccaria laccata formed in ectomycorrhizal associations with Pinus sylvestris, developed a mature pileus with an hymenium and mature basidiospores.
The worldwide decline in frogs has been linked to a deadly disease (Chytridiomycosis) caused by the chytrid fungus, Batrachochytrium dendrobatidis. We used Congo red to study chytrid fungi in skin scrapings taken from formalin preserved animals, from non-preserved decaying or dead animals, as well as from apparently healthy animals. We were able to distinguish immature and mature zoosporangia, zoospores and germling stages of the fungus within the host tissue. Staining patterns varied. Zoospores (including flagellum) stained orange but the walls of all other stages stained a reddish-orange. The inoperculate discharge tube was always intensely stained. However, when zoosporangia were within intact epidermal cells, only the exposed discharge tube stained unless the keratinized layer was breached. The epidermal cells either did not stain or stained pale orange. Congo red is cheap, easy to use and relatively non-hazardous, making it a valuable tool to study the spread and role of chytridiomycosis in frog decline.
European beech (Fagus sylvatica L.) is an important forest tree species which was always considered being non-problematic with regard to its susceptibility to pathogens and insects. However during the past decade, in Europe and the north-eastern USA an increasing number of trees and stands were showing symptoms typical for Phytophthora diseases: increased crown transparency, abnormally small and often yellowish foliage, a dieback of the crown, tongue-shaped necroses of the inner bark and the cambium with tarry or rusty spots on the surface of the bark either extending up to 7m from the stem base (collar rot) or occurring isolated higher up the stem (aerial bleeding cankers), fine root destructions and necrotic lesions on suberized roots. Large-scale investigations on both continents using specific isolation methods and ELISA kits for detection, and morphological and physiological parameters as well as ITS-DNA sequence analysis for identification demonstrated that several Phytophthora species were regularly involved as inciting agents of the decline. The most important species were Phytophthora citricola, P. cambivora and P. cactorum in Europe, and P. inflata in the USA. Their pathogenicity to beech was shown by stem inoculation and soil infestation tests performed by various groups. A small-scale nursery survey in Germany revealed that beech fields are regularly infested with various Phytophthora species. Options for disease management and control are discussed, and an emphasis is put on the prevention of disease spread via infested nursery stock.
Over the past decade the use of molecular techniques has provided new ways to study old questions about how ectomycorrhizal fungi interact with each other and their environment. In their simplest form, these methods enable researchers to identify vegetative stages of fungi that would be difficult, slow, or impossible to identify by morphological or culture-based methods. This has resulted in quantitative views of complex fungal communities, which in turn have revealed new and unexpected patterns in community structure. In addition, molecular methods have been used to identify individual genotypes of fungi. This information has provided insights into the way that particular species of ectomycorrhizal fungi spread in nature. In this article we will mention the basic techniques and briefly discuss some of the findings that have resulted. Advances in this field have recently been comprehensively reviewed for scientific audiences, and we refer readers that have a more technical interest or a need to access the current literature to these reviews (Dahlberg, 2001; Horton & Bruns, 2001).
Traditional methods alone often make it difficult to identify isolates to species level. Armillaria and Cylindrocladium are examples where new technologies could achieve this quickly and reliably. Rapid identification of pathogens is of great importance in their control, especially when dealing with quarantine organisms where detection of pathogens at early stages is critical.
The biological control of stump sprouting in American bird cherry (Prunus serotina) and poplar (Populus euramericana) by applying a mycelium suspension of Chondrostereum purpureum is outlined. This fungus is being commercially deployed as a mycoherbicide under the brand name BioChon in order to prevent stump sprouting in hardwoods. It acts as a wood decay promoter. Effectivity of BioChon applied to control stump sprouting in P. serotina generally results in a kill of about 95% two years after treatment, and it appears to be as effective on poplar.Research on C. purpureum is also being carried out in Canada to control unwanted hardwoods in silviculture, in Switzerland for vegetation management, and in New Zealand to control imported woody weeds in pastures. Infection danger to non-target plants due to use of this pathogen as a mycoherbicide seems to be negligible in most cases.Worldwide marketing of the fungus is discussed.
Interest in the genetics of marine fungi has focused upon the basis of stress adaptation and the control of the production of secondary metabolites and enzymes. Analysis by molecular genetics has been applied to marine fungal taxonomy, phylogeny and species identification. The advent of the Debaryomyces hansenii genome project and the influence of climate change on this research are discussed.
Invasive hyphal growth allows filamentous fungi to insinuate themselves in the solid materials that serve as their food sources. Hyphae overcome the mechanical resistance of plant and animal tissues, and other substances through the secretion of digestive enzymes and the exertion of force. This force is derived from the osmotically-generated turgor pressure within the hypha and is governed by wall loosening at the growing apex. This article offers a concise description of the biomechanics of this process.
Endothiella sp. was found associated with witches' broom symptoms of Tibouchina granulosa growing in a stretch of Atlantic rain forest in Rio de Janeiro, Brazil. The fungus was the anamorph of Cryphonectria cubensis, the eucalypt canker fungus. Host-range studies were performed involving 40 plant species belonging to 19 families and showed that C. cubensis has a wide potential host-range, concentrated on the Myrtales but including Persea americana (avocado) and Pouteria caimito. These are members respectively of the subclasses Magnoliidae and Dilleniidae, distantly related to plants of the subclass to which both eucalypt and T. granulosa belong (Rosidae). The finding of C. cubensis in balance with a population of a native species at a site isolated and distant from both eucalypt and clove plantations might be regarded as reinforcing the hypothesis of a Neotropical origin for the fungus as opposed to the hypothesis of the fungus being from Oceania and having cloves as its original host. The new alternative hypothesis (of separate origins from endemic hosts in the Neotropics, Africa and Oceania) should nevertheless be also considered.
Pinus caribaea and its varieties occur naturally in Central America and parts of the Caribbean region. Little is known about its mycorrhizal fungi, but it appears to share a remarkable number of fungal partners with pines in North America. Some fungi found with Caribbean pine in Belize are listed and discussed.
The striking reddish-pink colour of the phylloplane yeast Sporobolomyces roseus was found to be due to three major carotenoid pigments which were identified by UV and mass spectra as β-carotene, torulene and torularhodin. Simple protocols for the extraction of these pigments and their visual separation by thin-layer chromatography are presented. Ultrastructurally, the pigments were localized within numerous small lipid droplets. Putative physiological roles and the biotechnological relevance of carotenoids from red yeasts are discussed.
We report the recent widespread occurrence in Britain of Puccinia distincta, a rust fungus on wild and cultivated daisies (Bellis perennis). The rust is short-cycled, with only aecia and telia on Bellis, and may be of Australian origin. It is very similar to, and possibly derived from, the macrocyclic P. obscura, a rust indigenous to Britain which produces pycnia and aecia on Bellis and uredinia and telia on Luzula. However, it differs from another Australian introduction, the groundsel rust (P. lagenophorae). The disease caused by P. distincta is so severe that it seriously impairs growing of ornamental daisies.
Walls of rooms with an atmosphere enriched in ethanol often show thick coatings with mycelium of Racodium cellare. Wine cellars and distilleries in which alcoholic beverages are stored in barrels seem to be the main habitat of this mould which is credited with beneficial effects on the cellar atmosphere by removing malodorous volatile substances. The present article examines the taxonomy and biology of this remarkable fungus.
This report demonstrates the striking variability of mitochondria within and between different species of fungi from all major taxa, i.e., Oomycetes (Phytophthora erythroseptica), Zygomycotina (Basidiobolus ranarum, Mucor mucedo), Ascomycotina (Sordaria fimicola), Deuteromycotina (Botrytis cinerea, Fusarium culmorum) and Basidiomycotina (Schizophyllum commune). For light microscopy (LM), a simple procedure was used to highlight mitochondria in living hyphae. They appeared filamentous, sometimes exceeding 25 m in length, and were occasionally branched. Ultrastructural features were investigated by transmission electron microscopy (TEM) which revealed that mitochondria of P. erythroseptica and B. ranarum had tubular cristae whereas the cristae in all other species were lamellate. The value of mitochondrial ultrastructure as a tool for fungal phylogenetic analysis is discussed.
Although fungi are fundamentally important in our every day lives, the Kingdom is largely ignored by the National Curriculum in the United Kingdom. Consequently, children are missing out on being taught about a crucially important group of organisms. This paper aims to show the deficiencies in the curriculum specifications in UK primary and secondary schools, and describes a range of British Mycological Society learning resources designed to remedy the situation. These ready-made (and classroom-tested) lessons and workshop sessions cover a range of fungal topics from cell structure and function, through biotechnology to health topics and plant growth and disease. The resources include games and activities, aiming to increase knowledge and awareness of fungi in an active, entertaining way and thereby maintain interest in biology as a science.
White-rot fungi possess a unique oxidative mechanism by which the recalcitrant lignin component of wood is mineralised. The activity of lignin-degrading enzymes, chiefly lignin and manganese peroxidases, depends on several small organic molecules. Some of these (e.g. chloroanisyl alcohols) are chloroaromatics and may act as environmental pollutants in the forest soil, whereas the synthesis of others (e.g. veratryl alcohol) requires chloromethane. Certain white-rot genera, notably Phellinus and Inonotus, release excess quantities of chloromethane into the atmosphere where it acts as a greenhouse gas. On the other hand, their powerful ligninolytic system enables white-rot fungi to degrade a wide range of man-made environmental pollutants, including recalcitrant chloroaromatics such as DDT, PCP, 2,4-D and 2,4,5-T. This review describes the multifarious interactions of white-rot fungi with their environment via the chlorine cycle.
The monotypic genus Claustula (family Claustulaceae, order Phallales) is reported from several sites in Tasmania, having been known previously only from New Zealand. The characteristics of its receptacle and gleba, and the absence of columns, prevent it from being placed comfortably into either Clathraceae or Phallaceae. Within the hymenial layer clavate basidia and infrequent irregular elements bear spores of similar appearance, and the attachment of the receptacle is clarified. Some discussion is presented about the affinities of this species within the Phallales.
Confusion still surrounds the identify and even the common name of the causal agent of frosty pod rot of cocoa, nearly 70 years after its placement in the genus Monilia, and over 20 years since its transfer to the new genus Moniliophthora, which was erected to accommodate what was considered to be a basidiomycete anamorph. Based on molecular and cytological evidence, we confirm that the fungus belongs in the Basidiomycotina and is closely related to the witches' broom pathogen of cocoa, Crinipellis perniciosa (Tricholomataceae: Agaricales). However, the only known reproductive stage in the life-cycle does not, in fact, represent the anamorph since meiosis occurs during sporogenesis and germination. The meiospore is interpreted to be a radically modified basidium, which performs a sexual, dispersal and resting function. The genus Moniliophthora, therefore, can no longer be maintained and must be reduced to synonymy with Crinipellis. The new combination, Crinipellis roreri, is proposed.
Fungi can be found in almost any environment, and play important roles in ecosystem processes such as nutrient cycling and degradation. Despite their importance, the vast majority of fungi have not yet been isolated and identified. Due to the difficulties inherent in culture-based methods, fungal ecologists have turned to community fingerprinting techniques, which utilise signal molecules to profile the fungal members of an environmental sample without culturing. Commonly used signal molecules include chitin, ergosterol, membrane lipids, and nucleic acids. Several DNA-based fingerprinting methods have been successfully applied to fungal communities, including D/TGGE (denaturing/temperature gradient gel electrophoresis), SSCP (single-stranded conformational polymorphism), RISA (ribosomal intergenic spacer analysis), and T-RFLP (terminal restriction length fragment polymorphism). These techniques allow the fungal ecologist to rapidly profile fungal populations in an ecosystem, without the need for laborious culturing or cloning.
It has been known for a long time that fungi may transport substances in their hyphae. Experiments using radioactive tracer isotopes have greatly expanded our knowledge about translocation and have revealed that many fungi may circulate resources throughout their mycelia. This article outlines a conceptual framework for when and where net-translocation of resources takes place. Effects of substrate qualities, mycelial growth and activity as well as interactions with living plant hosts and other microorganisms are discussed and exemplified with experimental data. It is concluded that translocation from more or less remote parts of the mycelium enables fungi to colonise substrates with a low initial resource availability and to actively increase the resource availability in the substrates, turning the colonising mycelium from a resource sink into a source. Thus, translocation not only occurs in response to environmental heterogeneity, but also allows fungi to create heterogeneity in their growth environment.
The recent discovery of Crinipellis perniciosa (Stahel) Singer associated with witches' brooms on a new host plant, in a region far removed from its accepted natural range, raises fundamental questions about its origins and biology. In considering the past and present socio-economic importance of the pathogen in South America, it was felt that a semi-popular or non-specialist review of this highly problematic but still little-known fungus would be timely.
The lack of a standard procedure for isolation of Phytophthora infestans from tomatoes has been a major problem for researchers working on tomato late blight. There is an associated problem of culturing, especially in the tropics where standard media such as Rye A agar are not readily available. Efforts were made to try and develop isolation and culturing techniques based on tomato and locally available tropical cereals respectively. Two techniques for isolating. P. infestans from tomato tissue were successfully developed. The first was by placing young sterile healthy tomato slices on infected tomato leaves. A second technique was developed in order to make use of already diseased fruits. For both techniques. P. infestans grew well on tomato slices and subculturing was successfully made onto Rye A agar without the need of antibiotics.
The paper outlines the impact of molecular biology on the identification and detection of fungi and fungus-like micro-organisms. We have tried to use as little jargon as possible but avoiding it completely is very difficult. The article is centred around the ‘pseudofungus’ Phytophthora and its closest relatives, because that is the micro-organism with which we have had most experience. Nevertheless, most of the approaches and techniques mentioned are applicable to any fungus or fungus-like organism and, in that broader sense, the article should be of interest to those with no special interest in or knowledge of Phytophthora.
Phytophthora ramorum is a recently described species responsible for sudden oak death syndrome and also causes symptoms such as twig wilt and dieback, stem lesions, necrosis of leaf midrib from the petiole and leaf tip necrosis on a range of ornamental plant species. In the USA, a reported epidemic of P. ramorum infections on trees belonging to several families including Fagaceae, Lauraceae and Ericaceae seems to be increasing and there are fears of similar epidemics occurring in woodlands in the UK and mainland Europe. This paper reviews the current state of knowledge and the research efforts being made to understand the biology, manage the disease and prevent widespread outbreaks of P. ramorum infections across Europe and the USA.
Individual fungal cells within genetically-uniform populations can exhibit striking phenotypic variability. This phenotypic heterogeneity has been proposed recently to promote the fitness of fungal populations, independently of fitness contributions arising from genetic diversity. Consequently, several major recent studies have been focused on unravelling the physiological and molecular bases for heterogeneity. This article provides an overview of the current state of play in this emerging field, with a focus on heterogeneity in the single-cell yeast Saccharomyces cere-visiae and on the novel methodologies being developed to study heterogeneity.
Macrolepiota molybdites poisoning is suspected as the cause of an intoxication in four German Shepherd dogs. There was very strong circumstantial evidence that the dogs had eaten this fungus and the symptoms encountered were similar to those described for human poisoning with this species. To our knowledge this is the first report of poisoning by Macrolepiota molybdites in dogs.
Ectomycorrhizas (ECM) are dual organs formed between the terminal feeder roots of many plant species and certain soil fungi. The species richness and taxonomic diversity of ECM symbionts is impressive: ca. 7-10,000 fungal and ca. 8,000 plant species may be capable of forming ECM. The latter are the dominant components of forest and woodland ecosystems over much of the earth's surface. The obligate nature of the symbiosis for ECM fungi has been brought into question by reports that some species produce sporocarps under field conditions in the absence of a host plant. We suggest that there is no unequivocal evidence to support this. The spread of tree roots is often underestimated and small, overlooked hosts such as dwarf Salix spp or sedges may explain the appearance of ECM sporocarps in vegetation apparently devoid of ECM hosts. Compared to plant material, the sporocarps of ECM fungi contain high concentrations of N and P. We show that it would take between 3 and 14 million mycorrhizal tips, or 1800 km of hyphae, to supply the N in one sporocarp of Boletus edulis. The mantle formed by the fungus over the root tip is the likely site of storage for the N and P required for sporocarp production, and we discuss the chemical and structural mechanisms developed on mantles by ECM fungi to defend this resource against fungivory.
Eleven species of mushrooms are currently known to be utilized as a food source by the indigenous Patamona Amerindians of the rain forested Pakaraima Mountains of Guyana. The majority of these fungi are undescribed species; many belong to groups that are infrequently collected for the table by North Americans (e.g. Clavulinaceae, Sarcoscyphaceae, Amanitaceae) whereas groups which contain highly prized culinary mushrooms by north temperate standards (e.g. Cantharellaceae) are traditionally shunned by the Patamona. Here we discuss some of the more commonly collected mushroom species of the Patamona and their methods of preparation as well as some mushrooms that we have discovered to be choice edibles of the region.
We investigated post-fire morels (Morchella species), especially the “gray” morels of Idaho and Montana, by collecting ecological and genetic data and by interviewing commercial mushroom harvesters and buyers. Gray morels fruited exclusively in high-elevation Picea/Abies forests that had burned the preceding summer, predominantly in zones of moderate fire intensity as indicated by a layer of dead conifer needles on top of the fire ash. Genetic analysis revealed five varieties of morels among our specimens. Mushroom harvesters confirmed that gray morels are economically crucial to their business because they are typically large, heavy, and durable. Harvesters and buyers described the varieties of morels they encountered differently than mycologists did, but cooperative research could facilitate mutual understanding of morel diversity and benefit everyone involved.
Free-living nematodes, commonly known as eelworms, eat bacteria in the soil and may succumb to infection by delicate endoparasitic fungi. In the wild these fungi are host-dependent and infect nematodes with small unicellular spores that either lodge inside the nematode following ingestion, or adhere to the nematode cuticle. Some endoparasites, such as Drechmeria coniospora and Harposporium leptospira, are readily isolated, ubiquitous species, infecting common soil nematodes in a variety of substrates. Others, like the elusive Plesiospora globosa, are seldom seen because they are host-specific for rarer species of nematode occurring in specific habitats.
A brief introductory exercise in the use of on-line databases to examine fungal genes and their products is described. Fungal genes make particularly good teaching models owing to their relatively simple eukaryotic structure and wide range of homologues in higher organisms including humans. An evaluation of students' reactions to the exercise is included.
The study of the evolutionary history of organisms by tracing them to common ancestors is known as phylogenetics. Over the last 20 years or so, the increasingly widespread availability of molecular data has seen the blossoming of methodologies for converting DNA information to evolutionary trees and networks. This article will attempt to give an overview of some of the methods that are available, covering data types, considerations for their use, and methods by which evolutionary ancestry can be reconstructed. Where relevant, the text will include examples of the use of these methodologies for the obligately biotrophic plasmodiophorids.
Hydrophobins are proteins that appear unique to mycelial fungi. They play essential roles in the emergence of aerial structures, gas exchange in fruiting bodies and lichens, and in pathogenesis. These roles are all based on the remarkable properties of these proteins as observed in vitro.