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Showing papers on "Mycelium published in 1975"


Journal ArticleDOI
01 Jan 1975-Oikos
TL;DR: The results and the presumable preference of detritius-feeders for leaf areas with higheshyphal concentrations indicate that the significance of fungal substances in the diet of leaf-eating animals may be considerably higher than suggested by estimates of the average microbial biomass per unit weight of decomposing leaves.
Abstract: Dry weight, ash-free weight, protein and energy content of food and faeces of Gammarus pseudolimnaeus Bousfield on different diets were compared. When feeding on elm or maple leaves, approximatately 10 % of the dry weight, 14-18 % of the protein, and 17-19 % of the energy of the ingested material was assimilated. When mycelium of various fungi which commonly decompose leaves in streams was offered, Gammarus assimilated 42.6-75.6 % of the dry weight, 73.3-96.4 % of the protein, and 67.9-83.2 % of the energy of the food ingested. These results and the presumable preference of detritius-feeders for leaf areas with higheshyphal concentrations indicate that the significance of fungal substances in the diet of leaf-eating animals may be considerably higher than suggested by estimates of the average microbial biomass per unit weight of decomposing leaves.

144 citations


Journal ArticleDOI
TL;DR: It is suggested that the resistance of N-mice to mycelial development may be an important mechanism whereby natural resistance to A. fumigatus is conferred.
Abstract: Aspergillus fumigatus mycelium in untreated mice (N-mice) and cortisone acetate-treated mice (C-mice) has been quantified by chemical assay of fungal chitin. Cortisone pretreatment rendered mice more susceptible to infection by A. fumigatus (mean lethal dose at 20 days, congruent to 10(6) for N-mice; less than 10(4) for C-mice). In both N- and C-mice there was renal localization of mycelial infection at conidial doses less than the mean lethal dose. At a conidial dose greater than the mean lethal dose, mycelial infection was found in the kidneys and brain of N-mice and in the kidneys, liver, and heart of C-mice. Chitin assay results showed that A. fumigatus mycelium grew more rapidly in C-mice. It is suggested that the resistance of N-mice to mycelial development may be an important mechanism whereby natural resistance to A. fumigatus is conferred.

108 citations


Journal ArticleDOI
TL;DR: Analysis of results on surface colony growth and submerged "pellet" growth concluded that these disparate growth behaviours result from different habits of growth; in two-dimensional colony growth a new region of space if invaded by an amount of mycelium small in proportion to the final "carrying capacity" of the region, and in three-dimensional colonies growth a region is invaded with an amount to which the invading hyphae initially occupy the space.
Abstract: SUMMARY: Based on the assumption that mycelial growth follows the logistic growth law, formulae have been developed to express the growth of fungal colonies under a variety of geometric constraints. Analysis was done of Deppe's (1973) results on surface colony growth, where the mass of the colony grew exponentially during most colonial growth, and of Trinci's (1970) results on submerged ‘pellet’ growth, where the mass of the colony increased as the cube of time during most colony growth. In both cases the linear dimensions of the colony were increasing linearly while the mass was changing in these quantitatively different manners. It is concluded that these disparate growth behaviours result from different habits of growth; in two-dimensional colony growth a new region of space is invaded by an amount of mycelium small in proportion to the final ‘carrying capacity’ of the region, and in three-dimensional colony growth a region is invaded with an amount of mycelium almost equal to the region's final limiting mycelial mass. Thus, the types of growth law for colony mass which are applicable for a particular organism in a particular physical environment depend critically on the degree to which the invading hyphae initially occupy the space.

78 citations


Journal ArticleDOI
TL;DR: A comparison was made of the morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of Neurospora crassa, finding that E=Galpha was a function of the length of the mycelium's hyphal growth unit and the organism's specific growth rate.
Abstract: A comparison was made of the morphology and growth kinetics of hyphae of differentiated and undifferentiated mycelia of Neurospora crassa. Undifferentiated mycelia were formed during exponential growth on solid media or submerged culture. Hyphae at the margin of differentiated mycelia (colonies) differed from undifferentiated mycelia in diameter, extension rate, extension zone length, and intercalary and apical compartment length. The mean hyphal extension rate (E) of an undifferentiated mycelium was a function of the length of the mycelium's hyphal growth unit (G) and the organism's specific growth rate (α). Thus, E=Gα.

76 citations


Journal ArticleDOI
TL;DR: Attempts were made to elucidate the acetyl transformation of novel trichothecene mycotoxins, 3a,7a,15-trihydroxy-12,13-epoxytrichotheC-9-en-8-one (deoxynivalenol) and its derivatives, by trichothcene-producing strains of Fusarium nivale, F. roseum, and F. solani.
Abstract: Attempts were made to elucidate the acetyl transformation of novel trichothecene mycotoxins, 3α,7α,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one (deoxynivalenol) and its derivatives, by trichothecene-producing strains of Fusarium nivale, F. roseum, and F. solani. In the peptone-supplemented Czapek-Dox medium, F. roseum converted 3α-acetoxy-7α,15-dihydroxy-12,13-epoxytrichothec-9-en-8-one (3-acetyldeoxynivalenol) to deoxynivalenol. 3-Acetyldeoxynivalenol was also deacetylated by intact mycelia of the three strains in sugar-free Czapek-Dox medium. The growing F. nivale acetylated deoxynivalenol to afford a small amount of 3-acetyldeoxynivalenol. 3α,7α,15-Triacetoxy-12,13-epoxytrichothec-9-en-8-one (deoxynivalenol triacetate) was transformed by the intact mycelium of F. solani into 7α,15-diacetoxy-3α-hydroxy-12,13-epoxytrichothec-9-en-8-one (7,15-diacetyl-deoxynivalenol), which was then deacetylated to give 7α-acetoxy-3α,15-dihydroxy-12,13-epoxytrichothec-9-en-8-one (7-acetyldeoxynivalenol). It was noted that the ester at C-7 was not hydrolyzed by the fungal mycelium.

61 citations


Journal Article
TL;DR: Both superficial and deep infections were equally potent in the transmission of the disease and the fungus was highly pathogenic to seed and 40-day-old plants.
Abstract: A. rabiei infected 70% of C. arietinum samples from C. Anatolia, Turkey. The standard blotter method, using 5 seeds/Petri dish and 12 h NUV 12 h darkness cycles at 22 deg C, proved most suitable for detecting the fungus. The inoculum was spore contamination and mycelium occurred in the seed coat alone or in seed coat and embryo. Pycnidia were observed only in the seed coat of seeds having deep lesions. Inter- and intracellular mycelium was localized to lesions. Pycnidia were subepidermal and contained mature spores. Pycnidiospores obtained from the seed surface and pycnidia from 14-month-old seed stored at 3 plus or minus 2 deg showed 33% germination. The light and temp. responses of the fungus on PDA revealed that opt. colony growth occurred at 19 deg . Pycnidial formation was max. under NUV but failed in darkness. Both superficial and deep infections were equally potent in the transmission of the disease. The fungus was highly pathogenic to seed and 40-day-old plants.This paper was presented at the 17th Int. Seed Testing Congress 1974.

57 citations


Journal ArticleDOI
01 May 1975-Nature
TL;DR: The effect of sclareol on the germination and growth of rust fungi in vitro, and the protection it can provide to plants against diseases caused by these fungi are described.
Abstract: AN epimeric mixture of the diterpenes sclareol and 13-epi-sclareol (sclareol) (Fig. 1) has been shown to constitute 10%; of the surface exudate on leaves of Nicotiana glutinosa1. Investigations into its effect on fungal growth showed that it neither inhibits the spore germination of several species of facultative pathogens in vitro nor reduces the weight of mycelium produced in liquid medium. The development of hyphae of certain species of fungi, for example Alternaria brassicicola, is, however, markedly affected by this compound. In the presence of sclareol, increased branching is induced which leads to a substantial reduction in the diameter of colonies growing on agar1. Such morphological effects could be interpreted as the result of alterations in the regulation of natural fungal growth processes. This report describes the effect of sclareol on the germination and growth of rust fungi in vitro, and the protection it can provide to plants against diseases caused by these fungi.

57 citations


Journal ArticleDOI
TL;DR: Under semianaerobic conditions with high CO2 concentration in the gaseous phase of substratum, the competitive microorganisms are eliminated and Pleurotus mycelium can grow well in the non-sterile substratum.
Abstract: Summary 1. Increased CO2 concentration in the air has a positive effect on mycelium growth in the cultivation of Pleurotus ostreatus, P. florida and P. eryngii (Agar cultures). 2. Between 16% and 22% CO2 in the air is the optimum for the growth of the 3 above-mentioned Pleurotus species. 3. Concentrations of 36 vol.% CO2 inhibited growth of all 3 species. 4. Both sterile and pasteurized straw substrata showed 20-25% (of vol.) CO2 3 days after inoculation. Mycelium growth was normal. CO2 concen­ tration stands in relation to the amount of inoculation material, tem­ perature, composition of substratum, and other environmental factors. 5. The stimulating effect of CO2 on the growth of the Pleurotus species studied and their high tolerance to CO2 have a special importance in Pleurotus farming. 6. Under semianaerobic conditions with high CO2 concentration in the gaseous phase of substratiim, the competitive microorganisms are eli­ minated and Pleurotus mycelium can grow well in the non-sterile s\ibstratum.

42 citations


Journal ArticleDOI
TL;DR: Aspergillus niger was found capable of rapidly converting about 97% of the sugar from brewery spent grain liquor to fungal mass and reduced the biochemical oxygen demand by 96%.
Abstract: Aspergillus niger was found capable of rapidly converting about 97% of the sugar from brewery spent grain liquor to fungal mass. The yield of dry mycelium, based on the sugar consumed, was approximately 57%. This fungus produced 1.10% titratable acid calculated as citric acid and reduced the biochemical oxygen demand by 96%.

37 citations


Journal ArticleDOI
TL;DR: A layer of cells with pigmented thick walls (called brown matting) which differentiated at the air/agar interface was interpreted as an aspect of sclerotial behaviour since it was regularly formed by strains which produced submerged sclerotsia and was composed of cells of similar structure to those of the outermost layer of the submerged mycelotium.
Abstract: SUMMARY Sclerotia were formed in both aerial and submerged parts of the mycelium. In addition a layer of cells with pigmented thick walls (called brown matting) which differentiated at the air/agar interface was interpreted as an aspect of sclerotial behaviour since it was regularly formed by strains which produced submerged sclerotia and was composed of cells of similar structure to those of the outermost layer of the submerged sclerotium. Apart from producing sclerotia and oidiospores the cells of the aerial mycelium remained undifferentiated. In contrast, cells of the submerged mycelium, though initially indistinguishable from those of aerial hyphae, became individually differentiated within about 5 days of growth producing two further novel cell types; inflated cells containing glycogen, and hyaline thick-walled cells. Submerged sclerotia were pale brown in colour, irregularly shaped and about 0.5–1.0 mm in diameter. The only structure which differentiated the submerged sclerotium from the submerged mycelium was the outer rind, a layer of cells with thick, pigmented walls. The central (medulla) region contained the same cell types in the same frequencies as the general submerged mycelium. In sharp contrast the aerial sclerotia were highly organized structures composed of distinct and compact tissues. Mature aerial sclerotia were dark brown to black spheroidal structures up to 0.5 mm in diameter. An outer layer of dead and moribund hyphae surrounded the main body of the sclerotium which was bilayered with an outer rind and inner medulla. The rind was multilayered and consisted of small cells with thick pigmented walls; intercellular spaces were cuticularized. The medulla was a closely packed tissue composed predominantly of hyaline thick-walled cells of the same type as were encountered in the submerged mycelium.

32 citations


Journal ArticleDOI
TL;DR: The ultrastructure of developing and mature sclerotia of Sclerotium rolfsii was studied with a scanning electron microscope and it was found that the developing sclerots are large and almost completely filled with vesicles, whereas the medullar cells are smaller and some of them are very thickwalled.
Abstract: The ultrastructure of developing and mature sclerotia ofSclerotium rolfsii was studied with a scanning electron microscope. The mature sclerotium is disconnected from the mycelium and well differentiated. The rind is composed of rather thick-walled empty cells. The cortex cells are large and almost completely filled with vesicles, whereas the medullar cells are smaller and some of them are very thickwalled.

Journal ArticleDOI
TL;DR: Three forms of DNA-dependent RNA polymerase have been separated by chromatography of extracts of yeast-like cells and mycelium of the dimorphic fungus Mucor rouxii and each enzyme had a distinct pattern of activities with different templates.

Journal ArticleDOI
TL;DR: 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, which was similar at pH 2.5 and 6.0.
Abstract: 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 ofAspergillus 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.

Journal ArticleDOI
15 Apr 1975-Botany
TL;DR: Single-spore isolates of Botrytis cinerea from commercially stored cabbage exhibited a broad range of virulence and the concentration of nutrients and (or) spores influenced the ability of B. cinarea to cause tissue decay whereas spore age and bacterial populations did not.
Abstract: Single-spore isolates of Botrytis cinerea from commercially stored cabbage exhibited a broad range of virulence Spore germination and hyphal growth required an exogenous source of nutrients The ability of either spores or mycelium to cause infection of stored cabbage tissue was also dependent upon exogenous nutrients Nutrients required for infection could be supplied in the form of glucose, cabbage leaf extract, potato dextrose agar (PDA), or by a wound at the site of inoculation The concentration of nutrients and (or) spores influenced the ability of B cinerea to cause tissue decay whereas spore age and bacterial populations did not Spores on the surface of cabbage leaves germinated within 4 to 8 h in nutrient solution; an additional 8 to 16 h in nutrient solution were required for successful infection The optimum temperature for fungal growth and for infection was 20 to 25C The optimum relative humidity for decay was above 97%; decay did not occur at relative humidities below 93%


Journal ArticleDOI
TL;DR: Aspergillus nidulans was grown on media with added amounts of manganese ranging from 0–2.5 μM and it was revealed that α-1,3 glucan, the main carbon and energy source for fructification, was virtually absent from the cell wall.
Abstract: Aspergillus nidulans was grown on media with added amounts of manganese ranging from 0–2.5 μM. Manganese deficiency prevented cleistothecium development, although good vegetative growth was retained. Subsequent analysis of the mycelium produced under Mn2+ deficient growth revealed that α-1,3 glucan, the main carbon and energy source for fructification, was virtually absent from the cell wall. Several enzymes related to cell wall composition were investigated. β-1,3 glucanase, and very remarkably, α-1,3 glucanase reached about the same activity on the Mn2+ deficient and sufficient media, but amylase and protease were about 60 and 75% lower respectively on the Mn2+ deficient media and the correlation of these findings is discussed.

Journal ArticleDOI
TL;DR: In this paper, Aspergillus niger, the microorganism that showed the strongest antioxidant activity, was subjected to adsorption and gel permeation chromatography, and two fractions that protected lard against oxidation were obtained by chromatography of A. niger extract on Sephadex LH-20 and Bio-Beads S-X2.
Abstract: Extracts of six fungi, four yeasts, and two species of Streptomyces were tested for antioxidant activity when added to lard. Extracts of Aspergillus niger, the microorganism that showed the strongest antioxidant activity, were subjected to adsorption and gel permeation chromatography. Two fractions that protected lard against oxidation were obtained by chromatography of A. niger extract on Sephadex LH-20 and Bio-Beads S-X2. One of these fractions contained a gummy brown pigment BR, the other a bright yellow crystalline pigment Y. Pigment BR showed strong carbonyl group and methyl-methylene group absorption in the infrared. Apparently, on the basis of spectral data, pigment Y has a linear naphthopyrone structure. Pigment BR was obtained consistently from A. niger mycelium, while pigment Y was formed sporadically. Results indicated that more than one substance in A. niger mycelium have antioxidant properties and that brown and yellow pigments apparently are associated with antioxidant activity. Synergistic effects may be important in the strong antioxidant activity of A. niger extracts.

Journal ArticleDOI
TL;DR: Cyclopeptine dehydrogenase activity increased at the beginning of the alkaloid-production-phase, indicating that the enzyme is concerned in alkaloids metabolism.

Journal ArticleDOI
TL;DR: Histochemical assays were carried out on mycelium of Dendryphiella salina cultured in media containing either potassium chloride or sea water, finding that adenosine triphosphatase showed enhanced activity and potassium or sodium ions were added to the assays of material from the potassium chloride cultures.
Abstract: Histochemical assays were carried out on mycelium of Dendryphiella salina cultured in media containing either potassium chloride or sea water. Adenosine triphosphatase showed enhanced activity in mycelium from sea-water cultures. The addition of potassium or sodium ions to the assays of material from the potassium chloride cultures also increased this activity. There was less activity in young hyphal tips compared with older areas of the mycelium. These observations help to explain the compartmentation of potassium fluxes in the mycelium of Dendryphiella salina .

Patent
Arnaud Nicole1, David A. Bush1
30 Jan 1975
TL;DR: In this paper, a process for the production of α-galactosidase by culturing the mold Penicillium duponti in an aqueous medium containing at least one sugar with at least 1 αD-Galactopyranosyl bond was described.
Abstract: A process for the production of α-galactosidase by culturing the mold Penicillium duponti in an aqueous medium containing at least one sugar with at least one αD-galactopyranosyl bond and collecting the mycelium thus obtained.

Journal ArticleDOI
TL;DR: P. byssinum was found to be a strong inhibitor of the root rot agents Fomes annosus and Poria weirii in pure culture.
Abstract: The mycorrhizal associations Pseudotsuga menziesii+Cantharellus cibarius, P. menziesii+Inocybe geophylla and P. menziesii+Piloderma byssinum were demonstrated by comparing the mycorrhizal mantle with the sporocarp stipe base mycelium, with respect to morphology, reaction to chemical reagents and autofluorescence in long-wave ultraviolet light. P. byssinum was found to be a strong inhibitor of the root rot agents Fomes annosus and Poria weirii in pure culture.

Journal ArticleDOI
TL;DR: 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.
Abstract: 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

Journal ArticleDOI
P. Langcake1
TL;DR: Sterols were not detected in the mycelium of Phytophthora infestans when grown on a chemically denned sterol-free medium and preliminary studies of the metabolism of radiolabelled cholesterol showed some conversion to metabolites of lower polarity had occurred.
Abstract: Sterols were not detected in the mycelium of Phytophthora infestans when grown on a chemically denned sterol-free medium. The incorporation of various exogenously supplied sterols into the mycelium was demonstrated. The amounts of each sterol incorporated did not correlate with the ability of that sterol to stimulate vegetative growth of the fungus on agar medium. Inter-conversions within the mycelium of one sterol to another could not be detected with cholesterol, cholestanol, stigmasterol or β -sitosterol. There was some evidence for the conversion of lanosterol to cholesterol. The fate of exogenously supplied ergosterol was unclear. Radiolabel, supplied as [4- 14 C] cholesterol to the growing mycelium, became associated predominantly with a particulate subcellular fraction. The ability of Triton X-100 to solubilize this radiolabel suggested an association with membranes. A significant proportion of the radio-label was associated with the supernatant/oily fraction of the mycelial contents. Preliminary studies of the metabolism of radiolabelled cholesterol by P. infestans showed that some conversion to metabolites of lower polarity, probably by esterification, had occurred.

Journal ArticleDOI
TL;DR: The results suggested that more selective composts, favouring rapid mycelial colonization, would provide ‘cultural’ control of mushroom sciarids.
Abstract: SUMMARY The development of sciarids was reduced in old casing and in casing to which a commercial composting additive was added in large amounts. In laboratory tests, adding water, soya bean, cotton seed or oatmeal to finished mushroom composts reduced the mean development time of the larvae of Lycoriella auripila. Soya bean meal significantly increased the number of adult sciarids which matured. While the presence of mushroom mycelium in large quantities inhibited the development of sciarids, smaller amounts increased either the number of larvae maturing or their rate of development in different tests. Larvae were seen to feed on mycelium. The addition of sucrose solution either reduced or prolonged development time in different tests. Nitrogenous additives encouraged the growth of ‘weed moulds’. Both these and the number of sciarids which developed were reduced by adding a solution of calcium nitrate. The results suggested that more selective composts, favouring rapid mycelial colonization, would provide ‘cultural’ control of mushroom sciarids.

Journal ArticleDOI
TL;DR: The fatty acid composition of the total, neutral, sterol, free fatty acid, and polar-lipid fractions in the mycelium of Choanephora curcurbitarum was determined and showed no particular preference for any individual fatty acid; however, the degree of unsaturation was different in different lipid fractions.
Abstract: The fatty acid composition of the total, neutral, sterol, free fatty acid, and polar-lipid fractions in the mycelium of Choanephora curcurbitarum was determined. The major fatty acids in all lipid fractions were palmitic, oleic, linoleic, and gamma-linolenic acid. Different lipid fractions did not show any particular preference for any individual fatty acid; however, the degree of unsaturation was different in different lipid fractions. Free fatty acid and polar lipid fractions contained a higher proportion of gamma-linolenic acid than did triglyceride and sterol fractions. Addition of glutamic acid to the malt-yeast extract and medium resulted in the biosynthesis of a number of long-chain fatty acids beyond the gamma-linolenic acid. These fatty acids, e.g., C22:1, C24:0, and C26:0, were never observed to be present in the fungus when grown on a malt-yeast extract medium without glutamic acid. Furthermore, thin-layer chromatographic analysis showed a larger and denser spot of diphosphatidyl glycerol from the mycelium grown on glutamic acid medium than from the control mycelium. The possible significance of this finding is discussed.


Journal ArticleDOI
TL;DR: Propagules of Rhizoctonia solani grown in modified Czapek's medium containing sodium polypectate or carboxymethyl cellulose as a sole carbon source produced both extracellular and cell-bound polygalacturonase (PG), and cellulase (Cx), respectively, which were found to be associated with the cell wall fraction of the mycelium.
Abstract: Propagules of Rhizoctonia solani grown in modified Czapek's medium containing sodium polypectate or carboxymethyl cellulose as a sole carbon source produced both extracellular and cell-bound polygalacturonase (PG), and cellulase (Cx), respectively. The cell-bound enzymes can be released to various extents by shaking the germinating propagules in solutions of NaCl, KCl, phosphate buffer, Na2EDTA (ethylenediaminetetraacetate), detergents such as Triton X-100 (octyl phenoxypolyethoxyethanol), Tween 80 (polyoxyethylene sorbitan monooleate), Celmusol, and distilled water. Sodium dodecyl sulfate (SDS) inactivated both PG and Cx but did not affect Cx activity in phosphate buffer solution. PG was more easily released by salts from the mycelium of R. solani than Cx. The release of both enzymes was a passive process and was not due to an osmotic effect. The amount of the cell-bound fraction was correlated with the total amount of the extracellular fraction rather than with the mycelial growth. At least one-third of...

Journal ArticleDOI
TL;DR: Nine phenotypic mutants of the wild type of Penicillium stoloniferum NRRL5267 were obtained from conidia exposed to ultraviolet light for 60 min (10% survival), and virus levels ranged from 85 to 150 E-260 units (extinction units at 260 nm in I cm cell) per 4-7 to 5-3 g dry weight of mycelium for the mutant strains.
Abstract: SUMMARY Phenotypic mutants of the wild type of Penicilliu/ll stoloniferul11 NRRL 5267 were obtained from conidia exposed to ultraviolet light for 60 min (10 survival). Virus content of the wild type and of nine phenotypic mutants was determined by polyacrylamide gel electrophoresis. Four mutants had no detectable Penicilliul11 stoloniferul11 virus F (PsV-F), whereas the other five had levels of PsV-F in the mycelium similar to the wild-type strain. All nine mutants and the wild type had comparable levels of Penicilliul11 stoloniferul11 virus S (PsV-S). Maximum virus levels occurred after 9 days of submerged culture in a 2 yeast extract-I5 sucrose medium. Virus replication in the fungal host continued after protein, RNA and DNA synthesis levelled off. Virus levels ranged from 85 to 150 E2GO units (extinction units at 260 nm in I cm cell) per 4'7 to 5'3 g dry weight of mycelium for the mutant strains compared to 106 E260 units per 4'2 g dry weight of the wild-type strain.

Journal ArticleDOI
TL;DR: The größte Menge of Aflatoxin B2 wurde nach sieben Tagen Incubation beobachtet, while the Summe aller Aflatoxine nimmt von 83 bis auf 37% ab, wenn der Gehalt an Ammoniumsulfat im Substrat 5–20% Glucose enthielt.
Abstract: Spores of an aflatoxigenic strain ofAspergillus parasiticus were inoculated into a glucose-salts medium which was incubated with and without shaking at 28° C for 15 days Without shaking, maximal production of total aflatoxin and aflatoxins B1, G1, and G2, occured 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° C and production of total aflatoxin and of each individual toxin was less at 15° C than at 25 or 28° C

Journal ArticleDOI
TL;DR: In this paper, pieces of the fruit body of Stereum hirsutum attracted the migrating plasmodia of Badhamia utricularis at a distance of 4 cm.
Abstract: SUMMARY: Pieces of the fruit body of Stereum hirsutum attracted the migrating plasmodia of Badhamia utricularis at a distance of 4 cm. Extracts of fruit bodies made with organic solvents could attract, but aqueous extracts could not. Cultured mycelium and extracts of cultured mycelium also attracted strongly, but activity was not detected in culture filtrate. Phase separation with organic and aqueous phases concentrated the attractive principle. Paper chromatography indicated the presence of a single substance of high activity which migrated in isopropanol-ammonia-water with an RF of 0.83 to 0.88 and in butanol-acetic acid-water with an RF close to 0.9. The active extracts from fruit bodies and cultured mycelium were thermostable. The attractant diffused through both aqueous and gaseous phases.