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At least 19 recordsLinked to original sources

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↗

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↗

PubMedDate not supplied

[Fine structure of the outer sheath of the aerial mycelium in Actinomyces levoris].

The outer sheath of the aerial mycelium of Actinomyces levoris 64 bears groove-like and granular submicroscopic structures. They are very susceptible to a short-term treatment of the aerial mycelium with aqueous acetone which causes their disintegration. Under specified conditions, submicroscopic structures, viz. granules and threads, assemble from the acetone extract of the aerial mycelium of Actinomyces levoris. These structures possess the anti-yeast activity. The granular structures reorganized from the acetone extract of the aerial mycelium of Actinomyces levoris somewhat resemble in morphology the structures seen in the outer sheath of the aerial mycelium of this actinomycete. The results obtained are discussed within the framework of the hypothesis on a possible participation of polyene antibiotics in the formation of the outer sheath of the aerial mycelium of actinomycetes which produce these antibiotics.

Acetone↗

PubMed1976

Factors affecting production of mold mycelium and protein in synthetic media.

The effects of certain cultural conditions on the yield of dry mycelium, protein, and total amino acid content of Rhizopus oligosporus Saito (NRRL 2710), Rhizopus rhizopodiformis (Cohn apud Lichtheim) Zopf (NRRL 6246), and Absidia corymbifera (Cohn) Sacc. et Trotter (NRRL 6247) were studied. The yield of mycelium was found to significantly increase as the spore inoculum was increased from 187,500 to 2,250,000 spores. But the total amino acids (grams/liter) did not change significantly, whereas the percentage of crude protein decreased. An inoculum containing approximately 750,000 spores/ml was used in all of the other experiments. Mycelial production was highest at 37 degrees C for all three molds. However, the best temperature for percentage of crude protein and total amino acids varied with the organism. The mycelial yield and total crude protein of R. oligosporus showed some significant changes as the C/N ratio was increased in 3% glucose medium. In a synthetic medium having a 15:1 C/N ratio, the strains of R. oligosporus, R. rhizopodiformis, and A. corymbifera had better yields from falactose than glucose, not only in dry mycelium but also in total crude protein (grams/liter) and total amino acids (grams/liter). R. oligosporus grew very well on several ammonium salts. but the maximum yield of dry mycelium, total crude protein (grams/liter), and total amino acids (grams/liter) occurred with ammonium sulfate. The optimum pH for both Rhizopus species was 4.0, although R. oligosporus grew equally well at pH 3.0 and slightly less at pH 5.0. The highest yield of mycelium for A. corymbifera was obtained in a medium with an initial pH of 8.0. It was calculated that a fermenter chanrged with an adequate medium and 1,000 lb (about 450 kg) of R. oligosporus or A. corymbifera cells could produce 88 or 90 lb of protein (on a dry-weight basis) per h if the product was removed continuously.

Amino Acids↗

PubMed1979

Effects of low concentrations of zinc on the growth and dimorphism of Candida albicans: evidence for zinc-resistant and -sensitive pathways for mycelium formation.

In this analysis we have examined in detail the effects of low concentrations of zinc on the growth and dimorphism of Candida albicans. Evidence is presented that micromolar concentrations of zinc added to growth cultures grown at 25 degrees C (i) cause a twofold increase in the final concentration of spheres at sationary phase, (ii) result in an asynchronous block in the budding cycle at stationary phase, (iii) completely suppress mycelium formation in two independently isolated human strains which produce low but significant levels of mycelia at stationary phase, and (iv) completely suppress mycelium formation in cultures of mutant M10, in which over 60% of the cells form mycelia at stationary phase. In contrast, micromolar concentrations of zinc do not inhibit mycelium formation induced by releasing cells from stationary-phase cultures into fresh medium at 37 degrees C. In addition, if zinc is present in the growth medium of the initial culture at 25 degrees C, the average time of subsequent mycelium formation after release into fresh medium at 37 degrees C is halved. It is demonstrated that the above effects are specific to zinc. The possibility of alterante pathways for mycelium formation is suggested, and the medical implications of this possibility are discussed.

Candida albicans↗

PubMedDate not supplied

[Development and differentiation of mycelium of Trichothecium roseum in submerged culture].

Ontogenesis of Trichothecium roseum during biosynthesis of trichothecin was studied during submerged cultivation on maize and synthetic media. Growth of the fungus is polycyclic; several generations of the submerged mycelium develop from the submerged conidia on the maize medium, and from the submerged conidia, chlamydospores and budding mycelium on the synthetic medium. Differentiation of the mycelium favours biosynthesis of the antibiotic. The nuclei in the cells of the submerged mycelium differ by their number, dimensions, and shape (round and elongated, polyploid). Several nuclei are found in the cells of the submerged mycelium more often during growth on the synthetic medium; this phenomenon is related to the reproductive cells -- submerged conidia and chlamydospores.

Anti-Bacterial Agents↗

PubMed1975

Production of aflatoxin and its partition between the medium and the mycelium of Aspergillus parasiticus during incubation under various conditions.

Spores of an aflatoxigenic strain of Aspergillus parasiticus were inoculated into a glucose-salts medium which was incubated with and without shaking at 28 degrees C for 15 days. Without shaking, maximal production of total aflatoxin and aflatoxins B1, G1, and G2 occurred at 5 days, whereas the maximal amount of B2 appeared after 7 days. Initially approximately 5% of the total toxins appeared in the mycelium but this increased to more than 60% after 5 days. Shaking of cultures during incubation served to reduce production of total aflatoxin and of each of the individual toxins. The maximal amount of total aflatoxin and of toxins B1 and G1 appeared in shaken cultures after 5 days, whereas 8 and 11 days were needed to obtain maximal amounts of B2 and G2, respectively. The mycelium of shaken cultures initially retained approximately 50% of the total aflatoxin and this increased to about 80% as the incubation progressed. Very little aflatoxin was synthesized at 35 and 45 degrees C and production of total aflatoxin and of each individual toxin was less at 15 degrees C than at 25 or 28 degrees C. When the medium contained 0.5 to 50% glucose, maximal amounts of total aflatoxin and of aflatoxins B1, G1 and G2 appeared in the presence of 30% glucose; only 20% glucose was needed to obtain the greatest amount of B2. The mycelium retained approximately 50% of total aflatoxin when the medium contained 5 to 20%. Neither aflatoxin G1 nor G2 were detected when the medium contained 0.05% ammonium sulfate and only B1, B2, and G1 appeared in the medium with 0.1% of the salt. Maximal production of each individual aflatoxin and of total aflatoxin occured with 1% of ammonium sulfate in the medium. The proportion of total aflatoxin retained by the mycelium decreased from 83 to 37% as the amount of ammonium sulfate in the medium was increased from 0,05 to 10%.

Aflatoxins↗

PubMed1975

Aflatoxin can be degraded by the mycelium of aspergillus parasiticus.

Aflatoxins B1, B2, G1, and G2 were degraded by the 8- and 16-day old but not by the 4-day old mycelium of a toxigenic strain of Aspergillus parasiticus. The 16-day old mycelium degraded the toxin more rapidly than did the 8-day old mycelium. Degradation of toxin by the mycelium was similar at pH 2.5 and 6.0.

Aflatoxins↗

PubMed1977

[Biodegradation of the mycelium of Pyrenochaeta lycopersici Schneider et Gerlach in the soil. Ultrastructural study].

Under natural conditions, Pyrenochaeta lycopersici forms a sterile mycelium. Some strains form chlamydospores, while others form micro-sclerotia. The fungus survives by hyphae cells which are present in soil either free-living or momentarily protected by the tissue of the infected root. In a model experiment, the behaviour of the free mycelium was tested in a soil which had been supplied with asparagine and manure, respectively. A known quantity of living mycelium was added to the prepared soils. Samples were taken after 1, 3, 6, and 10 months. They were examined on loss of weight of the mycelium, inoculum potential, and ultra-structure of the hyphae before and during degradation by transmission electron microscopy.

Biodegradation, Environmental↗

PubMed1976

[Study of the chemical makeup of the mycelium from an active strain of Act. rimosus and from an inactive mutant in relaiton to oxytetracycline biosynthesis].

Chemical composition of the mycelium of the active and inactive mutants of Act. rimosus grown under conditions favourable for oxytetracycline biosynthesis on the starch or maltose medium and under favourable conditions on the glucose medium was studied. It was shown that according to its chemical composition the above strains did not practically differ. When grown on the starch medium the mycelium of both strains contained great amounts of carbohydrates and comparatively small amounts of nucleic acids and nitrogen. Replacement of starch in the medium by glucose or maltose induced significant changes in the mycelium composition: the synthesis of intracellular polysaccharides was markedly suppressed and the synthesis of nucleic acids and nitrogen containing compounds increased. RNA was the main nucleic acid in both strains on starch and glucose media. The content of DNA was low and did not practically change. The mycelium of both strains contained small amounts of lipids which did not significantly change during the process of cultivation and did not correlate with the antibiotic activity.

Carbohydrates↗

PubMed1975

Stereospecific analysis of major glycerolipids of Phycomyces blakesleeanus sporangiophores and mycelium.

The positional distribution of fatty acids was determined in the major groups of glycerolipids from the mycelium and sporangiophores of the fungus Phycomyces blakesleeanus. At the sn-1 positions of the triacylglycerols, in both regions of the fungus, greater than 65% of the fatty acids were 16:0 and 18:1. At the sn-2 positions of the triacylglycerols, 18:1, 18:2 and 18:3 comprised greater than 85% of the sporangial fatty acids and more than 90% of the mycelial fatty acids. Positions sn-3 of the triacylglycerols, from both regions of the fungus, contained approximately 40% of 16:0, approximately 30% of 18:2, and the largest proportions of 18:3 (21%) in the triacyglycerols. The major phosphoglycerides of P. blakesleeanus mycelium and sporangiophores are phosphatidylcholine and phosphatidylethanolamine, and more than 85% of the fatty acids at the sn-1 positions of these phosphatides consisted of 16:0, 18:2, and 18:3. The sn-2 positions of phosphatidylcholine and phosphatidylethanolamine contained approximately 98% unsaturated fatty acids. In the phosphoglycerides of both regions of the fungus, 18:2 and 18:3 constituted greater than 85% of the total fatty acids. Although the mycelium and sporangiophores of P. blakesleeanus had different morphological and physiological characteristics, the major glycerolipids of the two regions had similar stereospecific distributions of fatty acids.

Fatty Acids↗

PubMed1976

Uptake and efflux of succinic acid by uninduced mycelium of Claviceps purpurea.

Claviceps purpurea PRL 1980 grew on partially dissociated succinic acid (pH 4) but not on fully dissociated succinic acid (pH 7.2). Myeclium suspended in 42 mM solution of partially ionized succinic acid (pH 4; 60.1% nonionized, 39% monoanion, and 0.9% dianion, K+ salt) over a period of 25 min accumulated more succinic acid carbon than mycelium suspended in highly ionized solution (pH 6.8; 0.01% nonionized, 4.8% monoanion, and 95% dianion). The greater accumulation from partially ionized solution was not attributable solely to metabolism of succinic acid nor to the lower external concentration of potassium ion. Rate of uptake by sodium azide and iodoacetate-treated mycelium was proportional to external concentration at least up to 200 mumol/ml. External potassium or sodium ion was not required for uptake by inhibited or uninhibited mycelium and external sodium ion and glucose did not allow concentration of succinic acid. The internal concentrations of succinic acid carbon expressed as succinic acid in cell water were about the same as the external concentrations. Uptake was not appreciably affected by extent of ionization of external succinic acid but accumulation was markedly affected. A plot of accumulated succinic acid carbon against external pH produced a bimodal curve with the two maxima corresponding to the maximal concentrations of nonionized and monoanion succinic acid. The bimodal curve probably results from overlapping of two separate curves; the nonionized form accumulating efficiently because of one interaction with the cell and the monoanion form accumulating efficiently because of another interaction. Uptake from concentrated solution is by diffusion and efflux is rapid but not complete. Efflux is not retarded by presence of phosphate in the external solution.

Azides↗

PubMedDate not supplied

[Morphofunctional changes in the mycelium of active and inactive variants of Actinomyces parvullus during growth and biosynthesis of actinomycin D].

The structure and function of the mycelium were studied with active and inactive variants of Actinomyces parvillus producing actinomycin D. Changes in the morphology were found in the hyphae of the active variant during its growth and production of the antibiotic: the cell wall became first thicker in the course of growth and then thinner with aging; the ribosomes aggregated prior to intensive synthesis of actinomycin but disintegrated later into fine-granular regions; electron-trasnparent bodies of irregular shape appeared in the cytoplasm, and their content was liberated into the medium upon lysis of the cytoplasmic membrane and cell wall. These changes were not detected in the mycelium of the inactive variant. The disintegrated mycelium of the active variant was studied by differential ultracentrifugation, and the electron-transparent bodies in the cells were presumed to be of the antibiotic nature. A capsule is formed around the hyphae at the beginning of the antibiotic synthesis, and thickens in the course of growth. Intrahyphal hyphae are very often encountered in the culture. Possible mechanisms protecting cells in unfavourable conditions are discussed.

Actinomyces↗

PubMed1979

[Characterization of mitochondria of Aspergillus niger from mycelium growing in surface and submerged culture conditions (author's transl)].

This paper deals with studies on tightly coupled mitochondria present in the active citric acid producing mycelium of Aspergillus niger growing in surface and submerged culture. A special homogenizer had been used for rapid extraction of mitochondria. Observation in the electron microscope indicated that some of the isolated mitochondria were probably damaged during preparation. Nevertheless, the crude mitochondrial fraction was capable of coupling phosphorylation to the oxidation of three different substrates tested viz., succinate, citrate and NADH. It was found that yield of mitochondria was greater in submerged mycelium than in the surface mycelium of A. niger.

Aspergillus niger↗

PubMedDate not supplied

[Effect of polyploidogenic factors on Trichothecium roseum mycelium in the process of trichothecine and fibrinolytic enzyme biosynthesis].

The effect of colchicine and boric acid on the substrate mycelium of Trichothecium roseum was studied in the course of trichothecin biosynthesis. Addition of boric aicd (0.01%) and colchicine (0.1%) to the medium for biosynthesis increased the antibiotic activity of the fungus, this being due to the specific effect of polyploidogenous factors on growth of the mycelium and the proportion of nuclei in it. The number of nuclei increased in cells of the substrate mycelium correlating with a higher antibiotic activity.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Effect of colchicine and other polyploidogenic factors in contact with the deep vegetative mycelium of the fungus Trichothecium roseum--producer of the antibiotic trichothecin and proteolytic enzymes].

Colchicine, boric acid, and camphor were used to produce viable cultures of Trichothecium roseum actively producing the antibiotic, by treating the submerged vegetative mycelium of the fungus with these compounds. Colchicine (0.5--1.0%), boric acid (0.25--2.00%), and camphor (0.25--1.50%) were added to the nutrient medium before it was inoculated with conidia or vegetative mycelium; later, the submerged mycelium was transferred to slanted agar. The cultures were characterized by a high number of the nuclei in the conidia, a low ratio of the plasma to the nuclei, a high rate of growth, and a high antibiotic activity. In sharply varying conditions of nutrition, such polynuclear forms had an adaptive advantage as compared to the parent forms. The polynuclear cultures are regarded to be biologically equal to polyploid forms.

Anti-Bacterial Agents↗

PubMed1976

Carbohydrate metabolism in Agaricus bisporus (Lange) Sing: changes in soluble carbohydrates during growth of mycelium and sporophore.

Changes in the ethanol-soluble carbohydrate content of Agaricus bisporus mycelium and sporophores grown on semi-defined media and commercial compost were studied. The accumulation of mannitol in the sporophore during its growth was not accompanied by an increase in mycelial mannitol. The other major soluble carbohydrate of the sporophore, trehalose, decreased throughout the growth of the sporophore; a parallel decrease was observed in the mycelium. The main accumulation of mannitol was in the pileus and stipe of the sporophore and was accompanied by a decrease in the soluble protein content of these tissues. Before fruiting, glucose and sucrose were present in the mycelial samples in similar quantities to mannitol, but their levels decreased during fruiting. Small quantities of glucose were present in the sporophore. The results are discussed in relation to the possible functions of the soluble carbohydrates.

Basidiomycota↗

PubMed1976

Existence of a surface configuration on the aerial spore and aerial mycelium of Micropolyspora.

We report the existence of a surface configuration in a true spore-forming genus having cell wall constituents of type IV. Micropolyspora angiospora, M. caesia and M. faeni freeze-fractured along the wall surface and only had a surface configuration on their aerial mycelium and aerial spores, with none on the substrate mycelium and substrate spore. The surface configuration of Micropolyspora was distinctly more complicated than that of Nocardia. The aerial spores of M. angiospora were characteristic in that they possessed ridges, two kinds of surface configurations (i.e. rodlets and fibres), and a complex pattern on the surface. Some rodlets of this organism were formed of a two-stranded helix, each strand having a diameter similar to that of a fibre.

Actinomycetales↗