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At least 19 recordsLinked to original sources
PubMed2005

A death round affecting a young compartmentalized mycelium precedes aerial mycelium dismantling in confluent surface cultures of Streptomyces antibioticus.

Development-associated cell-death processes were investigated in detail during the growth and differentiation of Streptomyces antibioticus ATCC 11891 on confluent surface cultures, by using fluorescent viability probes, membrane and activity fluorescence indicators, and electron microscopy analysis. A previously unsuspected complexity was revealed, namely the presence of a very young compartmentalized mycelium that dies following an orderly pattern, leaving alternating live and dead segments in the same hypha. This death round is followed by the growth of a second mycelium which develops rapidly from the live segments of the first mycelium and dies massively in a second death round, which extends over the phases of aerial mycelium formation and sporulation.

Cell Membrane Permeability↗
PubMed1984

Synthesis and degradation of aflatoxins by Aspergillus parasiticus. I. Synthesis of aflatoxin B1 by young mycelium and its subsequent degradation in aging mycelium.

Aflatoxin production and degradation were examined in three isolates of A. parasiticus. Maximum yields were present after incubation for 14 days and these declined gradually as the culture aged. Young mycelia (4 days old) synthesized the greatest amounts of aflatoxin, but aging mycelia (14 days old) were mainly responsible for degradation. Addition of cycloheximide to young cultures and removal of mycelia from aging cultures both prevented further aflatoxin degradation. Intramycelial substances released from fragmented or homogenized mycelium were capable of degrading aflatoxins, and their concentration increased as the mycelium aged. When 14C-labelled aflatoxin was added to a 2-day-old culture and further incubated, 75% of the radioactivity at 12 days was intramycelial, but at 20 days, most radioactivity was in the filtrate.

Aflatoxin B1↗
PubMed2001

Rates and quantities of carbon flux to ectomycorrhizal mycelium following 14C pulse labeling of Pinus sylvestris seedlings: effects of litter patches and interaction with a wood-decomposer fungus.

We used a novel digital autoradiographic technique that enabled, for the first time, simultaneous visualization and quantification of spatial and temporal changes in carbon allocation patterns in ectomycorrhizal mycelia. Mycorrhizal plants of Pinus sylvestris L. were grown in microcosms containing non-sterile peat. The time course and spatial distribution of carbon allocation by P. sylvestris to mycelia of its mycorrhizal partners, Paxillus involutus (Batsch) Fr. and Suillus bovinus (L.): Kuntze, were quantified following 14C pulse labeling of the plants. Litter patches were used to investigate the effects of nutrient resource quality on carbon allocation. The wood-decomposer fungus Phanerochaete velutina (D.C.: Pers.) Parmasto was introduced to evaluate competitive and territorial interactions between its mycelial cords and the mycelial system of S. bovinus. Growth of ectomycorrhizal mycelium was stimulated in the litter patches. Nearly 60% of the C transferred from host plant to external mycorrhizal mycelium (> 2 mm from root surfaces) was allocated to mycelium in the patches, which comprised only 12% of the soil area available for mycelial colonization. Mycelia in the litter patch most recently colonized by mycorrhizal mycelium received the largest investment of carbon, amounting to 27 to 50% of the total 14C in external mycorrhizal mycelium. The amount of C transfer to external mycelium of S. bovinus following pulse labeling was reduced from a maximum of 167 nmol in systems with no saprotroph to a maximum of 61 nmol in systems interacting with P. velutina. The 14C content of S. bovinus mycelium reached a maximum 24-36 h after labeling in control microcosms, but allocation did not reach a peak until 56 h after labeling, when S. bovinus interacted with mycelium of P. velutina. The mycelium of S. bovinus contained 9% of the total 14C in the plants (including mycorrhizae) at the end of the experiment, but this was reduced to 4% in the presence of P. velutina. The results demonstrate the dynamic manner in which mycorrhizal mycelia deploy C when foraging for nutrients. The inhibitory effect of the wood-decomposer fungus P. velutina on C allocation to external mycorrhizal mycelium has important implications for nutrient cycling in forest ecosystems.

Autoradiography↗
PubMed1976

The effect of some organic substances on the mycelium of the fungus Ustilago nuda (Jens.) Rostr.

Research was performed for studying the effect of some organic compounds, considered by many authors as the products ob barley seed metabolism generated after anaerobic seed treatment, on the mycelium of the fungus Ustilago nuda (Jens.) Rostr. The author examined the effectiveness of ethylacohol, acetaldehyde, acetic acid, succinic acid, lactic acid, and hydroquinone in concentrations from 1 M to 10(-6) M, and the effectiveness of extracts from disinfected seeds in doses from 10 g to 0.001 g/l. The effect of the mentioned solutions was examined as exerted on the growth of dicaryotic mycelium and on the growth of the haploid promycelium of the fungus. The dicaryotic mycelium of Ustilago nuda (Jens.) Rostr. was cultivated on potato agar with benzoic acid. The presence of the acid prevents mitosis, and the chlamydospores germinate on the nutritive medium with two fibres having binuclear cells. The haploid promycelium was cultivated on potato agar; chlamydospores germinated with one four-cell fibre, and individual cells are mononuclear and haploid. Only later, a dicarytic mycelium is created in a complex process. In all the substances used, the concentration of 1 M was found to stop further growth of mycelium. The concentration of 10(-1) M of acetic acid and hydroquinone also stopped growth, the same concentration of acetaldehyde, lactic acid, succinic acid, ethylacohol stimulated mycelium growth in comparison with the control. The concentration of 10(-6) M stimulated mycelium growth in a majority of cases. Extracts from disinfected seeds did not influence mycelium growth significantly in all cases in comparison with the control. The results were similar in the two types of mycelium.

Acetaldehyde↗
PubMed1963

STREPTOMYCIN FORMATION BY INTACT MYCELIUM OF STREPTOMYCES GRISEUS.

Nomi, Ryosaku (Rutgers, The State University, New Brunswick, N.J.). Streptomycin formation by intact mycelium of Streptomyces griseus. J. Bacteriol. 86:1220-1230. 1963.-A study was made of streptomycin formation by intact mycelium of Streptomyces griseus 107 grown in glucose-yeast extract medium. When mycelium harvested after 24, 48, and 72 hr was compared, the earliest growth showed the highest activity in producing streptomycin from glucose. The concentration of streptomycin in the mycelium was higher in the older growth. Calcium chloride had a remarkable effect in increasing streptomycin production from the precursors in the mycelium, especially when the mycelium was grown for 48 hr or longer. The effect of calcium chloride cannot be attributed to the precipitation of an excess of inorganic phosphate in the medium. Glucose, fructose, glycerol, lactic acid, glucosamine, streptidine, and inositol stimulated streptomycin formation, whereas gluconic acid, glucuronic acid, streptamine, and strepturea did not. When 24-hr-old mycelium was suspended and shaken in 0.5% glucose solution, the antibiotic precursors necessary to produce streptomycin were found mainly in the supernatant of the culture rather than in the mycelium. The supernatant included some substance which had a weak antibiotic activity. This substance was less basic than streptomycin and was transformed to streptomycin with a remarkable increase in antibiotic activity.

Anti-Bacterial Agents↗
PubMed2003

Accumulation of 137Cs by fungal mycelium in forest ecosystems of Ukraine.

During 1996-1998, 16 fruit bodies of different species and 204 soil samples down to 10 cm in the close vicinity of the fruit body sites were collected in a coniferous forest in the Ovruch region of Ukraine. The soil samples were sliced into 1 or 2 cm layers and the fungal mycelium was prepared from each of the layers. The 137Cs activity concentration was determined in both soil and mycelium. The mean weight of fungal mycelium was 13.8 mg g(-1) of soil in the upper 4 cm and 7.3 mg g(-1) when measured for the upper 10 cm. At the sites of Paxillus involutus and Sarcodon imbricatus, the mycelium was rather homogeneously distributed in the upper 10 cm and at sites of Xerocomus subtomentosus and Cantharellus cibarius, the mycelium was distributed mostly in the upper layers. The highest 137Cs activity concentrations were found in the upper layers of the soil profile. The 137Cs activity concentrations were usually higher in the fruit bodies compared with the mycelium, with ratios ranging from 0.1 to 66 and a mean of 9.9. The percentage of the total inventory of 137Cs in the soil found in the fungal mycelium ranged from 0.1 to 50%, with a mean value of 15%.

Cesium Radioisotopes↗
PubMed1996

Inhibition of yeast-to-mycelium conversion of Candida albicans by conjugated styryl ketones.

Candida albicans is a dimorphic pathogenic yeast capable of producing alternate morphological forms (yeast or mycelium) in response to environmental changes. The dimorphism of C. albicans plays an important role in the pathophysiology of this organism. The intracellular level of glutathione, which helps to maintain the oxidation-reduction potential of the cell, is decreased significantly during the yeast-to-mycelium conversion implicating the possible involvement of thiols in the yeast-to-mycelium transition. To evaluate the possible participation of sulphydryl group(s) containing component(s) in the yeast-to-mycelium transition of C. albicans, we examined the effect of a group of newly synthesized thiol-alkylators on the production of germ tubes from yeast cells. Several conjugated styryl ketones which are thiol-alkylators, and p-chloromercuriphenylsulphonate (a known nonpenetrating thiol-blocker) inhibited the yeast-to-mycelium conversion of C. albicans. The thiol-alkylators at 20 microM failed to inhibit four key enzymes (gamma-glutamyltranspeptidase, glutathione reductase, glutathione S-transferase and glutathione peroxidase) involved in glutathione utilization indicating that the inhibition of yeast-to-mycelium conversion is not mediated by the inhibition of glutathione metabolic enzymes. Moreover, these results suggest that a key thiol-blocker sensitive component(s) containing a critical sulphydryl group(s) is involved in the yeast-to-mycelium transition of C. albicans.

4-Chloromercuribenzenesulfonate↗
PubMed1984

[Oleandomycin content of mycelium and fermentation solution during cultivation of Streptomyces antibioticus].

The time-course of the oleandomycin content in the mycelium and fermentation broth-filtrate was studied by the microbiological assay at different periods of cultivation of strains 471 and 961 in fermenters and flasks containing a rich soybean-corn medium. It was shown that centrifugation of the mycelium over the sucrose density gradient induced a 25-80 per cent decrease in its moist weight at the expense of removal of the admixture components of the rich medium. Addition of glucose (2 per cent) to the culture-grown in a lactose medium by the 72nd hour of fermentation had no effect on further increase of the cell biomass. However, it lowered the content of the mycelium-fixed and excreted antibiotic at all the subsequent fermentation periods. The content of oleandomycin in the untreated mycelium was only 0.36 per cent of its content in the fermentation broth filtrate. After centrifugation of the mycelium over the sucrose density gradient and its intensive washing with distilled water the content of the mycelium-fixed antibiotic decreased still more. The time-course of the content of the mycelium-fixed and excreted oleandomycin was characterized by the presence of two activity peaks; by the 80-110th and by the 140-170th hour of cultivation.

Culture Media↗
PubMed1981

[Development of a gentamicin producer under different culture conditions studied by a method of differential centrifugation of the mycelium in a saccharose density gradient].

The method of differential centrifugation in the sucrose density gradient (SDG) enabled one to trace the changes in the development of the seed and fermentation mycelium of the gentamicin-producing organism. Correlation between gentamicin distribution in the SDG and the culture productivity was found. It was shown that the culture grown under the optimal aeration and agitation conditions was characterized by formation of higher amounts of the mycelium in the 5th and 6th layers of the SDG. Such mycelium was more productive than that from the other SDG layers. The most productive 48-hour seed culture had the more significant part of the mycelium in the 3rd layer of the SDG. When such a culture had the more significant part of the mycelium in the 3rd layer of the SDG. When such a culture was used as the seed material, the activity of the fermentation broth was the highest. The method of differential centrifugation in the SDG provides determination of the culture productivity by the volumes of the fermentation mycelium in the 5th and 6th layers or the seed mycelium in the 3rd layer of the SDG.

Centrifugation, Density Gradient↗
PubMed2005

The elemental content in the mycelium of the ectomycorrhizal fungus Piloderma sp. during the colonization of hardened wood ash.

Piloderma sp., a wood ash-colonizing ectomycorrhizal (EM) fungus, was grown symbiotically with Norway spruce in microcosms which contained granules of hardened wood ash. Mycelium close to the granules was sampled 3 times over a period of 11 weeks and the elemental content was investigated with particle induced X-ray emission. Mycelium from microcosms without wood ash was used as controls. The contents of P and K were similar in mycelium growing close to wood ash granules to those in control mycelium, while the Ca content increased from 23+/-21 mg g(-1) in controls to 63+/-8 mg g(-1) in mycelium growing close to wood ash granules. The Ca content was also increased in other parts of the mycelium more distant from the wood ash. Piloderma sp. may have a role in the short-term storage of Ca released from wood ash, rather than in releasing and storing P.

Basidiomycota↗
PubMed2004

Development of extraradical mycelium of Scutellospora reticulata under root-organ culture: spore production and function of auxiliary cells.

The development of the extraradical mycelium and auxiliary cells and spore production of Scutellospora reticulata in association with Ri T-DNA transformed carrot roots was followed under root-organ culture conditions. Extraradical mycelium development followed classical lag-exponential-plateau phases, with an additional late decline phase in number of auxiliary cells. Spore production started in parallel with a critical extraradical mycelium biomass produced, continued long after root growth ceased and during the late decline in auxiliary cells number. Isolated auxiliary cells were shown to exhibit hyphal re-growth, but not root colonization, either in situ or in vitro. These results showed that root and extraradical mycelium development were intimately associated in a sequence where both grew together during active root growth, followed during root aging by a period in which only the fungus developed. Spore production appeared dependent on a critical extraradical mycelium biomass and on the re-allocation of resources from both the intraradical mycelium and the auxiliary cells via the hyphal network.

Mycelium↗
PubMed2006

Mycelium cultivation, chemical composition and antitumour activity of a Tolypocladium sp. fungus isolated from wild Cordyceps sinensis.

AIMS: To examine and illustrate the morphological characteristics and growth kinetics of Cs-HK1, a Tolypocladium fungus, isolated from wild Cordyceps sinensis in solid and liquid cultures, and the major chemical constituents and antitumour effects of Cs-HK1 mycelium. METHODS AND RESULTS: The Cs-HK1 fungus was isolated from the fruiting body of a wild C. sinensis and identified as a Tolypocladium sp. fungus. It grew rapidly at 22-25 degrees C on a liquid medium containing glucose, yeast extract, peptone and major inorganic salts, with a specific growth rate of 1.1 day(-1), reaching a cell density of 23.0 g dw l(-1) in 7-9 days. Exopolysaccharides accumulated in the liquid culture to about 0.3 g l(-1) glucose equivalent. In comparison with natural C. sinensis, the fungal mycelium had similar contents of protein (11.7-microg) and carbohydrate (654.6-microg) but much higher contents of polysaccharide (244.2 mg vs 129.5 mg), adenosine (1116.8-microg vs 264.6 microg) and cordycepin (65.7 microg vs 20.8 microg) (per gram dry weight). Cyclosporin A, an antibiotic commonly produced by Tolypocladium sp., was also detected from the mycelium extract. The hot water extract of mycelium showed low cytotoxic effect on B16 melanoma cells in culture (about 25% inhibition) but significant antitumour effect in animal tests, causing 50% inhibition of B16 cell-induced tumour growth in mice. CONCLUSIONS: The Tolypocladium sp. fungus, Cs-HK1, can be easily cultivated by liquid fermentation. The mycelium biomass contained the major bioactive compounds of C. sinensis, and the mycelium extract had significant antitumour activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The Cs-HK1 fungus may be a new and promising medicinal fungus and an effective and economical substitute of the wild C. sinensis for health care.

Animals↗
PubMed1978

Exogenous regulators in the mycelium of Pleurotus ostreatus after exogenous application.

The mycelium of the fungus Pleurotus ostreatus was cultured on a synthetic medium with growth regulators. Best growth was observed on media with 100 ppm IAA, 200 ppm GA3 and 200 ppm of kinetin. Growth of terminal hyphae and the appearance of colonies differed characteristically. Auxin bio-assays showed that the content of substances in younger mycelium slowly increased during cultivation without conspicuous changes in the medium. After exogenous application of IAA the content of auxins in younger mycelium increased and the content of IAA decreased gradually in the culture medium. Gibberellin bio-assays showed their content in the mycelium fell during cultivation and while it increased in the medium. Application of GA3 to the medium leads to a significant increase in these substances in the young mycelium and in the medium their level remains the same. Cytokinin bio-assays showed their content to vary during cultivation. An addition to kinetin to the nutrient medium results in an increase of cytokinins in the mycelium while in the medium the level of cytokinins is maintained. Addition of one substance thus influences the levels of other endogenous regulators.

Agaricales↗
PubMed1993

Comparison of Psilocybe cubensis spore and mycelium allergens.

BACKGROUND: Basidiospores are an important cause of respiratory allergy in mold-sensitive atopic subjects. Collection of the large amounts of spores required for extract preparation is tedious and difficult. A desirable alternative could be mycelium grown in vitro if it is allergenically similar to spores. METHODS: Therefore this study compared the allergen contents of Psilocybe cubensis spore and mycelium extracts by different techniques with the use of pooled sera from subjects who had skin test and RAST results that were positive to P. cubensis spores. RESULTS: Isoelectric focusing immunoprints revealed six common IgE-binding bands at isoelectric points 4.7, 5.0, 5.5, 5.6, 8.7, and 9.3. Two additional bands at isoelectric points 3.9 and 5.7 were detected only in the spore extract. Sodium dodecylsulfate-polyacrylamide gel electrophoresis immunoblots exhibited six common IgE-binding bands at 16, 35, 487, 52, 62, and 76 kd; 20 and 40 kd bands were present only in the spore extract. Although RAST and isoelectric focusing inhibition demonstrated that P. cubensis spore and mycelium extracts share many allergens, spores were allergenically more potent than mycelium. CONCLUSION: The results indicate that mycelium is a useful source of P. cubensis allergen, even though several spore allergens were not detected in mycelium.

Agaricales↗
PubMed1994

Role of mycelium and extracellular protein in the biodegradation of 2,4,6-trichlorophenol by Phanerochaete chrysosporium.

The biodegradation of 2,4,6-trichlorophenol (2,4,6-TCP) by Phanerochaete chrysosporium was studied in batch systems. In experiments with mycelial suspension, the degradation of 2,4,6-TCP was found to occur in the absence of ligninase. Chloride ion was recovered in nearly stoichiometric amounts at the end of the process. The microorganism did not retain its degradation ability for more than 6 days under substrate-deficient conditions. Neither the mycelium nor the extracellular protein alone could degrade 2,4,6-TCP; both were required for complete degradation to occur. In experiments in which 2,4,6-TCP was exposed to the culture supernatant separated from its mycelium, negligible degradation was obtained and no chloride ion was recovered. No degradation was observed even when the supernatant was supplemented with hydrogen peroxide as a possible cosubstrate. In experiments performed with washed mycelium separated from its supernatant, no degradation took place until the mycelium released additional extracellular protein 5 to 6 h into the incubation. Additions of washed mycelium separated from its supernatant to active cultures also produced an increase in the rate of degradation in correspondence with the protein release. The protein release was independent of the presence of 2,4,6-TCP. The addition of cycloheximide to inhibit the synthesis of de novo proteins completely suppressed the release of protein by the mycelium and resulted in no 2,4,6-TCP degradation. Additions of culture supernatants containing a high concentration of extracellular protein to active cultures produced an increase in the rate of 2,4,6-TCP degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Basidiomycota↗
PubMed1967

Respiratory Activity of the Mycelium of Eremothecium ashbyii.

The respiratory activity of the mycelium of Eremothecium ashbyii from submerged cultures was manometrically determined at different stages of its development and the results were statistically analyzed. The experiments were performed in a manner designed to diminish the endogenous respiration without affecting the response to the addition of an exogenous substrate. Lactose was the carbohydrate tested that produced the lowest oxygen consumption. The oxidation of maltose, which was high at 24 hr, decreased by more than 50% at 48 and 55 hr. Glucose and sucrose were actively oxidized by mycelium of three ages. From the intermediates of carbohydrate metabolism, 24-hr mycelium did not produce oxygen consumption with malate, lactate, citrate, fumarate, and alpha-ketoglutarate. At 48 hr, mycelium did not oxidize either lactate or citrate; 55-hr mycelium showed oxygen consumption with all intermediates tested. Acetate and pyruvate always produced high oxygen consumption. Ethyl alcohol produced high oxygen consumption with mycelium of all tested ages.

Journal Article↗
PubMed1967

Release of proteinase from mycelium of Mucor hiemalis.

When Mucor hiemalis NRRL 3103 was grown in soybean medium, only a small fraction of the proteinase produced by the organism appeared in the culture filtrate, whereas the bulk of the enzyme was bound to the mycelial surface. Optimal pH of the proteinase ranged from 3.0 to 3.5. Inclusion of sodium chloride or other ionizable salts in the growth medium, however, resulted in the liberation from the mycelium of the loosely bound enzyme as it was formed. Maximal release of proteinase was achieved at a sodium chloride concentration of 0.5 m. The loosely bound proteinase was eluted also from intact resting mycelium by ionizable salts but not by water or by nonionizable substances. The amount of enzyme eluted from the mycelium depended upon the concentration of sodium chloride up to 0.3 m. Since liberation took place rapidly even at 0 C, a loose ionic linkage must exist rather than a biochemical binding of the enzyme to the mycelium. The recovery of proteolytic activity from repeated salt extractions was greater than that originally detected in the intact mycelium, possibly owing to unmasking of more active enzymes or functional groups. Further proteinase activity was released when salt-extracted mycelium was ruptured. Part of the proteinase thus observed was firmly attached to the cell fraction, and part of it appeared in the supernatant fluid. These conditions implied the presence of intracellular or firmly attached proteinase which could be partially released.

Culture Media↗