Agaricus
Agaricales
Fungal Polysaccharides
Fruiting Bodies, Fungal
Basidiomycota
Cell water balance of white button mushrooms (Agaricus bisporus) during its post-harvest lifetime studied by quantitative magnetic resonance imaging. (1/174)
A combination of quantitative water density and T2 MRI and changes therein observed after infiltration with 'invisible' Gd-DTPA solution was used to study cell water balances, cell water potentials and cell integrity. This method was applied to reveal the evolution and mechanism of redistribution of water in harvested mushrooms. Even when mushrooms did not lose water during the storage period, a redistribution of water was observed from stipe to cap and gills. When the storage condition resulted in a net loss of water, the stipe lost more water than the cap. The water density in the gill increased, probably due to development of spores. Deterioration effects (i.e. leakage of cells, decrease in osmotic water potential) were found in the outer stipe. They were not found in the cap, even at prolonged storage at 293 K and R.H.=70%. The changes in osmotic potential were partly accounted for by changes in the mannitol concentration. Changes in membrane permeability were also indicated. Cells in the cap had a constant low membrane (water) permeability. They developed a decreasing osmotic potential (more negative), whereas the osmotic potential in the outer stipe increased, together with the permeability of cells. (+info)A sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus. (2/174)
Aspergillus niger is known for its efficient excretion machinery. However, problems have often arisen in obtaining high amounts of heterologous proteins in the culture medium. Here we present a quick method using sandwiched colonies to evaluate transgenic strains for secretion of heterologous proteins. Expressing the ABH1 hydrophobin of Agaricus bisporus in A. niger, we showed that low production levels of the heterologous protein are probably due to extracellular proteolytic degradation of the protein. (+info)PCR-based genotyping of epidemic and preepidemic Trichoderma isolates associated with green mold of Agaricus bisporus. (3/174)
We used randomly amplified polymorphic DNA (RAPD)-PCR to estimate genetic variation among isolates of Trichoderma associated with green mold on the cultivated mushroom Agaricus bisporus. Of 83 isolates examined, 66 were sampled during the recent green mold epidemic, while the remaining 17 isolates were collected just prior to the epidemic and date back to the 1950s. Trichoderma harzianum biotype 4 was identified by RAPD analysis as the cause of almost 90% of the epidemic-related episodes of green mold occurring in the major commercial mushroom-growing region in North America. Biotype 4 was more closely allied to T. harzianum biotype 2, the predominant pathogenic genotype in Europe, than to the less pathogenic biotype 1 and Trichoderma atroviride (formerly T. harzianum biotype 3). No variation in the RAPD patterns was observed among the isolates within biotype 2 or 4, suggesting that the two pathogenic biotypes were populations containing single clones. Considerable genetic variation, however, was noted among isolates of biotype 1 and T. atroviride from Europe. Biotype 4 was not represented by the preepidemic isolates of Trichoderma as determined by RAPD markers and PCR amplification of an arbitrary DNA sequence unique to the genomes of biotypes 2 and 4. Our findings suggest that the onset of the green mold epidemic in North America resulted from the recent introduction of a highly virulent genotype of the pathogen into cultivated mushrooms. (+info)Different temporal and spatial expression of two hydrophobin-encoding genes of the edible mushroom Agaricus bisporus. (4/174)
In a search for genes that are only expressed in fruit bodies of the basidiomycete Agaricus bisporus, two cDNAs, hypA and hypB that encode hydrophobins have been isolated previously. In this study, the structure of hypB is resolved and it is shown that the two genes are differentially expressed, indicating that the encoded hydrophobins serve different functions in A. bisporus mushrooms. hypB encodes a polypeptide (HYPB) of 119 aa that shows little sequence identity with HYPA apart from the characteristic arrangement of eight cysteines found exclusively in hydrophobins. The temporal and spatial expression of the two hydrophobin-encoding genes during fruit body development was compared using Northern analysis and in situ hybridization. Accumulation of hypA mRNA was found in tissue fractions consisting of undifferentiated white hyphae. In situ hybridization showed that the highest hypA mRNA levels are not found in the outermost cell layers of the pileipellis but in the cell layers adjacent to that. The highest level of expression of hypB occurs early in development when the primordium differentiates into densely packed, randomly oriented cap hyphae and loosely packed, vertically oriented stipe hyphae. In mature mushrooms, a strong accumulation of hypB transcripts was found only in the transitional zone between cap and stipe tissue, demonstrating that transcription regulation of hypB is clearly distinct from hypA. (+info)Identification of a subgenomic mRNA encoding the capsid protein of mushroom bacilliform virus, a single-stranded RNA mycovirus. (5/174)
Mushroom bacilliform virus is unique among mycoviruses of the higher fungi in having a genome of positive-sense single-stranded RNA. We have identified a subgenomic mRNA molecule encoding the viral capsid protein in mushroom bacilliform virus-infected mycelium of Agaricus bisporus. Transcription of subgenomic RNA commences at the sequence ACAAAA, 47 nucleotides upstream of the initiating AUG. (+info)Abr1, a transposon-like element in the genome of the cultivated mushroom Agaricus bisporus (Lange) Imbach. (6/174)
A 300-bp repetitive element was found in the genome of the white button mushroom, Agaricus bisporus, and designated Abr1. It is present in approximately 15 copies per haploid genome in the commercial strain Horst U1. Analysis of seven copies showed 89 to 97% sequence identity. The repeat has features typical of class II transposons (i.e., terminal inverted repeats, subterminal repeats, and a target site duplication of 7 bp). The latter shows a consensus sequence. When used as probe on Southern blots, Abr1 identifies relatively little variation within traditional and present-day commercial strains, indicating that most strains are identical or have a common origin. In contrast to these cultivars, high variation is found among field-collected strains. Furthermore, a remarkable difference in copy numbers of Abr1 was found between A. bisporus isolates with a secondarily homothallic life cycle and those with a heterothallic life cycle. Abr1 is a type II transposon not previously reported in basidiomycetes and appears to be useful for the identification of strains within the species A. bisporus. (+info)Transport of amino acids and ammonium in mycelium of Agaricus bisporus. (7/174)
Mycelium of Agaricus bisporus took up methylamine (MA), glutamate, glutamine and arginine by high-affinity transport systems following Michaelis-Menten kinetics. The activities of these systems were influenced by the nitrogen source used for mycelial growth. Moreover, MA, glutamate and glutamine uptakes were derepressed by nitrogen starvation, whereas arginine uptake was repressed. The two ammonium-specific transport systems with different affinities and capacities were inhibited by NH(+)(4), with a K(i) of 3.7 microM for the high-velocity system. The K(m) values for glutamate, glutamine and arginine transport were 124, 151 and 32 microM, respectively. Inhibition of arginine uptake by lysine and histidine showed that they are competitive inhibitors. MA, glutamate and glutamine uptake was inversely proportional to the intracellular NH(+)(4) concentration. Moreover, increase of the intracellular NH(+)(4) level caused by PPT (DL-phosphinotricin) resulted in an immediate cessation of MA, glutamine and glutamate uptake. It seems that the intracellular NH(+)(4) concentration regulates its own influx by feedback-inhibition of the uptake system and probably also its efflux which becomes apparent when mycelium is grown on protein. Addition of extracellular NH(+)(4) did not inhibit glutamine uptake, suggesting that NH(+)(4) and glutamine are equally preferred nitrogen sources. The physiological importance of these uptake systems for the utilization of nitrogen compounds by A. bisporus is discussed. (+info)Janthinobacterium agaricidamnosum sp. nov., a soft rot pathogen of Agaricus bisporus. (8/174)
A novel bacterium has been found that causes a soft rot disease of Agaricus bisporus, the cultivated mushroom. It has been characterized using nutritional, physiological, chemical and molecular techniques. Based on these data, it was shown to have many characteristics in common with members of the genus Janthinobacterium. Despite similarities to the only described species within this genus, Janthinobacterium lividum, there were a number of differences between the mushroom pathogen isolated and this species. Despite the high degree of genotypic similarity between members of the genus Janthinobacterium and Herbaspirillum, as evidenced by DNA-RNA hybridization, and the high degree of 16S rDNA sequence similarity between members of the genera Janthinobacterium, Herbaspirillum, Oxalobacter and Duganella, as well as the generically misnamed Pseudomonas lemoignei, it was possible to show that members of the genus Janthinobacterium could be easily distinguished from these taxa. The data also indicated that the mushroom pathogenic strains represent a novel species within the genus Janthinobacterium for which the name Janthinobacterium agaricidamnosum sp. nov. is proposed. The type strain of this species has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany, as DSM 9628T and at the National Collection of Plant-pathogenic bacteria, UK, as NCPPB 3945T. To aid practical control of the disease, the effect of the relative humidity on symptom expression on Agaricus bisporus was determined. (+info)'Agaricus' is a genus of fungi that includes many species commonly known as mushrooms. These fungi are saprophytic, meaning they obtain their nutrients by decomposing organic matter. One of the most well-known and widely consumed species in this genus is 'Agaricus bisporus,' which includes varieties such as the white button mushroom, cremini, and portobello mushrooms. These edible fungi are rich in various nutrients, including proteins, fiber, vitamins, and minerals.
It's important to note that some species of Agaricus can be toxic or even hallucinogenic, so proper identification is crucial before consuming any wild mushrooms. Always consult a knowledgeable expert or use reliable resources for identification to avoid potential poisoning.
Agaricales is an order of fungi that includes mushrooms, toadstools, and other gilled fungi. These fungi are characterized by their distinctive fruiting bodies, which have a cap (pileus) and stem (stipe), and gills (lamellae) on the underside of the cap where the spores are produced. Agaricales contains many well-known and economically important genera, such as Agaricus (which includes the common button mushroom), Amanita (which includes the deadly "death cap" mushroom), and Coprinus (which includes the inky cap mushrooms). The order was established by the Swedish mycologist Elias Magnus Fries in 1821.
Fungal polysaccharides refer to complex carbohydrates that are produced and found in fungi, including yeasts, molds, and mushrooms. These polysaccharides are made up of long chains of sugar molecules that are linked together by glycosidic bonds.
Fungal polysaccharides have various structures and functions depending on the specific fungal species they come from. Some fungal polysaccharides, such as beta-glucans, have been shown to have immunomodulatory effects and are used in some medical treatments. Beta-glucans, for example, can stimulate the immune system's response to infections and cancer.
Other fungal polysaccharides, such as chitin, are structural components of fungal cell walls. Chitin is a polysaccharide made up of N-acetylglucosamine units and is also found in the exoskeletons of insects and crustaceans.
Fungal polysaccharides have been studied for their potential therapeutic uses, including as antimicrobial, antitumor, and immunomodulatory agents. However, more research is needed to fully understand their mechanisms of action and potential benefits and risks.
A fruiting body, in the context of mycology (the study of fungi), refers to the part of a fungus that produces spores for sexual or asexual reproduction. These structures are often what we typically think of as mushrooms or toadstools, although not all fungal fruiting bodies resemble these familiar forms.
Fungal fruiting bodies can vary greatly in size, shape, and color, depending on the species of fungus. They may be aboveground, like the caps and stalks of mushrooms, or underground, like the tiny, thread-like structures known as "corals" in some species.
The primary function of a fruiting body is to produce and disperse spores, which can give rise to new individuals when they germinate under favorable conditions. The development of a fruiting body is often triggered by environmental factors such as moisture, temperature, and nutrient availability.
Basidiomycota is a phylum in the kingdom Fungi that consists of organisms commonly known as club fungi or club mushrooms. The name Basidiomycota is derived from the presence of a characteristic reproductive structure called a basidium, which is where spores are produced.
The basidiomycetes include many familiar forms such as mushrooms, toadstools, bracket fungi, and other types of polypores. They have a complex life cycle that involves both sexual and asexual reproduction. The sexual reproductive stage produces a characteristic fruiting body, which may be microscopic or highly visible, depending on the species.
Basidiomycota fungi play important ecological roles in decomposing organic matter, forming mutualistic relationships with plants, and acting as parasites on other organisms. Some species are economically important, such as edible mushrooms, while others can be harmful or even deadly to humans and animals.
Mycelium is not a specifically medical term, but it is a biological term used in fungi and other organisms. Medically, it might be relevant in certain contexts such as discussing fungal infections. Here's the general definition:
Mycelium (my-SEE-lee-um) is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. It is the underground portion of the fungus that supports the growth of the organism and is often responsible for the decomposition of organic material. Mycelium can be found in various environments, including soil, water, and dead or living organisms.