Showing papers on "Mycelium published in 1977"

Vital staining of fungi in pure cultures and in soil with fluorescein diacetate

Abstract: A method for vital staining of fungal mycelium with fluorescein diacetate (FDA) is described. In experiments with pure cultures, good correlation was obtained between relative staining efficiency, growth rate, and respiration. FDA thus appears to be a true vital stain, in that it stains only metabolically active mycelia. In fresh soil suspensions stained with FDA, brightly fluorescent hyphae and portions of hyphae were observed. The applicability of the method for measurement of active mycelium in the soil is discussed.

The development of endomycorrhizal root systems: i. spread of infection and growth‐promoting effects with four species of vesicular‐arbuscular endophyte

Abstract: SUMMARY Four vesicular-arbuscular endophytes were inoculated into onions cultured in soil in a growth chamber. Dry weight, root length, infected root length, phosphorus content and quantity of external mycelium were measured at intervals. Three endophytes produced similar hyphal inflows, growth increments and external mycelium. One endophyte produced no growth increase in the host, and had little external mycelium and slow increase in percentage infection.

Fruiting of Agaricus bisporus

Abstract: Several enzymes were assayed in extracts from mycelium-colonised compost during growth and fruiting of Agaricus bisporus (Lange) Imbach. Comparison of changes of enzyme levels in axenic and nonaxenic cultures and in cultures of non-fruiting strains indicated that they were associated directly with the fungal mycelium. Large changes were found in the amounts of laccase and cellulase which were correlated with fruit body development. Laccase concentration increased during mycelial growth and then declined rapidly at the start of fruiting. Cellulase activity could be detected throughout growth but increased at fruiting. No such changes were observed in xylanase, alkaline protease, laminarinase and acid and alkaline phosphatases. Activities of laccase and cellulase were measured in axenic cultures arrested at various stages of fruiting development. Such cultures showed that the changes in concentration of laccase and cellulase were associated with the enlargement of fruit bodies.

Critique of the chitin assay technique for estimation of fungal biomass

Abstract: Colorimetric determination of chitin content of nine aero-aquatic hyphomycetes showed that the conversion factor (CF) values (chitin content per unit dry weight of mycelium) varied with the age of mycelium, nutrient content of the medium, and initial oxygen concentration of the water. CF values often decreased with age of mycelium and also with lowered oxygen concentrations. Consequently, for estimation of fungal biomass in tissues, this technique is of limited value.

Selective isolation and occurrence of nocardiae in soil

Abstract: Nocardiae were isolated from 15 out of 47 soils using Diagnostic Sensitivity Test Agar supplemented with antibiotics. Up to 7.3 × 10 4 g −1 dry wt. soil were counted, indicating that these bacteria might be more widespread and important than previously thought. Study of randomly selected isolates showed that they formed fragmenting mycelium, contained arabinose, galactose, meso-diaminopimelic acid and nocardomycolic acids. They clustered with Nocardia asteroides markers in a numerical taxonomic analysis.

Antifungal antibiotic of the basidiomyceteOudemansiella mucida

Abstract: Nuclear ratios were studied in terminal and subterminal cells of various mycelia of the basidiomyceteOudemansiella mucida, the producer of the antifungal antibiotic mucidin (MuciderminR Spofa). The dikaryon, the monokaryon, and the mucidin-producing strain that had been cultivated for a long time under submerged conditions were compared. Dedikaryotization was found to have taken place in the producing strain. The originally dikaryotic culture with characteristic clamp connections on the mycelium and with two nuclei in every hyphal cell lost permanently the clamp connections, probably owing to continuous intense agitation. The hyphae contained solely mononuclear cells. Mating with a compatible monokaryon yielded a dikaryon capable of normal fructification.

Studies on fungi cultivated by ants

Abstract: A collection of 36 fungi cultivated by leaf-cutting ants has been established at The New York Botanical Garden. These fungi grow on a variety of natural media and on a synthetic medium with mineral salts, dextrose, casein hydrolysate, purine and pyrimidine bases and vitamins. Tests of the fungi for antibacterial activity were all negative againstStaphylococcus aureus andEscherichia coli. Only four isolates of ant fungi, each cultivated by a different species of ant, produced basidiocarps on oatmeal agar. Taxonomic studies indicate that these belong to the same species of fungus (Lepiota sp.). Eighteen isolates produced bromatia characteristic of the form species,Attamyces bromatificus Kreisel, one produced a mycelium with clamp connections, and thirteen produced sterile mycelia without clamped hyphae and without bromatia.

Two metabolites from Aspergillus flavipes.

Abstract: Two novel fungal metabolites, N-benzoyl-L-phenylalaninol (1a) and asperphenamate (2) were isolated from the culture filtrate and mycelium of Aspergillus flavipes ATCC 11013. N-benzoyl-L-phenylalaninol was identified by direct comparison with an authentic sample. The structure of asperphenamate is proposed as (S)-N-benzoyl-phenylalanine-(S)-2-benzamido-3-phenyl propyl ester, based on chemical and spectroscopic evidence.

Ethylene Production and Mycelium Growth of the Tulip Strain of Fusarium oxysporum as Influenced by Shaking of and Oxygen Supply to the Culture Medium

Abstract: The fungus Fusarium oxysporum Schlecht f. sp. tulipae Apt. can produce ethylene abundantly in vitro when grown in Pratt's liquid medium with glucose as the only organic substrate. This production starts after a lag phase of about 4 days, and peak production occurs when mycelium weight has reached its maximum value. For several days the rate of production is more or less linearly dependent on pO2. The total production is also dependent on the oxygen concentration, but pure oxygen inhibits the total production by about 50% as compared with 21% oxygen. The high production in shake cultures, as compared with the low production in stagnant cultures, is probably the result of a better oxygen supply in the culture medium. The mycelium weight proved not to be a valid referential basis for the production of ethylene.

Subcellular Localization of Glucanase and Cellulase in Saprolegnia monoica Pringsheim

Abstract: (1#3)-β-Glucanase and cellulase, thought to be involved in the growth and branching processes of Saprolegnia monoica hyphae, were mainly localized at the edge of the colony. Autolysis of purified cell walls occurred preferentially in newly-formed walls. This process was also more important in walls of branched hyphae than in those of unbranched mycelium. Intracellular fractions were separated and characterized by density gradient ultracentrifugation, enzymic tests and electron microscopy. The fractions rich in β-glucanase and cellulase contained dictyosomes and apical vesicles. In agreement with cytological descriptions of the apex, the present results confirm the role of these ‘morphogen’ enzymes in hyphal morphogenesis.

Root Exudates From Eucalyptus calophylla R.Br. And Eucalyptus marginata Donn. ex Sm. Seedlings and Their Effect on Phytophthora cinnamomi Rands

Abstract: Root exudates from seedling eucalypts were collected aseptically, analysed for sugars, amino acids and organic acids and an examination made of their effect on zoospore chemotaxis, mycelium growth and chlamydospore germination of Phytophthora cinnamomi. Seedlings of root-rot susceptible Eucalyptus marginata produced greater concentrations of sugar and amino acid exudates than the root-rot resistant Eucalyptus calophylla at all sampling times. There was, however, little qualitative difference between the eucalypt root exudates. Both eucalypts attracted zoospores to roots in culture tubes. Infection of the roots followed encystment and germination of the zoospores. Germination of chlamydospores and mycelium growth of P.cinnamomi was significantly increased by the presence of root exudates and no differences were observed between exudates of the two species. Only amino acids and organic acids stimulated germination of chlamydospores. It was concluded that differences in root-rot susceptibility of eucalypts to P.cinnamomi are not attributable to differences in root exudate from eucalypt seedlings.

Effect of Carbon Dioxide on Growth and Carbohydrate Metabolism in Sclerotium rolfsii

Abstract: SUMMARY: Carbon dioxide at a concentration of 1 to 2% (v/v) in air enhanced the growth rate and inhibited sclerotium formation in the fungus Sclerotium rolfsii Sacc. A CO2 concentration of 10% inhibited growth. Similar growth patterns were observed when the fungus was grown on a medium supplemented with the fungicide carboxin, which inhibits succinate dehydrogenase. A high CO2 concentration (1 to 10%) or growth on carboxin-supplemented medium caused a decrease in succinate dehydrogenase activity and significant increases in isocitrate lyase, isocitrate dehydrogenase, malate synthase and malate dehydrogenase activities. Mycelium of S. rolfsii grown at a high CO2 concentration contained less glyoxylate, lipids and glycogen than mycelium grown in air. It is suggested that sclerotium formation in S. rolfsii requires a balanced supply of carbohydrate intermediates and energy.

Autolysis of Neurospora crassa in different culture conditions and release of β-N-acetyl-glucosaminidase and chitinase

Abstract: Autolysis of fungal mycelium is a complex phenomenon attributed to lytic enzymes contained in the mycelium itself or excreted into the medium. Many studies on physiological changes during autolysis have been carried out ( Lahoz, et al, 1966 , Lahoz and Gonzalez Ibeas, 1968 , Trinci and Righelato, 1970 ), but few accounts of autolysis have referred to the production of lytic enzymes during this process ( Vessey and Pegg, 1973 , Reyes and Byrde, 1973 ). We have found that changes in culture conditions, e.g. flow of air, rate of shake, temperature, influence the degree of autolysis. The comparative autolysis of Neurospora crassa in different culture conditions and the release into the medium of two lytic enzymes, β-N-acetylglucosaminidase and chitinase, are presented here.

Carbohydrate metabolism in agaricus bisporus (lange) imbach.: metabolism of [14c] labelled sugars by sporophores and mycelium

Abstract: SUMMARY When growing sporophores and vegetative mycelium of Agahcus bisporus had been supplied with [14C] labelled hexoses for varying periods of time, the major compounds labelled in both forms were mannitol, trehalose, glutamate, alanine and an unidentified substance. Mannitol was strongly labelled after application of [14C] fructose but only weakly when [14C] glucose was supplied. The relative rates of oxidation by sporophores of labelled mannitol, trehalose, glucose and fructose were assessed by measuring 14CO2 production. Glucose and trehalose were the most rapidly oxidized substrates. Glucosephosphatase isomerase (E.C. 5.3.1.9) was extracted from sporophores and assayed. The conversion of glucose-6-phosphate to fructose-6-phosphate by the enzyme was competitively inhibited in vitro by 6-phosphogluconate. The control of mannitol synthesis and the functions of mannitol and trehalose are discussed.

Carbohydrate Metabolism in Agaricus bisporus: Oxidative Pathways in Mycelium and Sporophore

Abstract: Summary: The relative rates of the glycolytic pathways were compared in vegetative mycelium and sporophore tissue of Agaricus bisporus. Simple radiorespirometry gave a C-1/C-6 ratio of 8.3 for pileus slices and 4.6 for vegetative mycelium. Glucose-6-phosphate dehydrogenase activity was greater in sporophores than in vegetative mycelium; glucosephosphate isomerase activity was higher in the mycelium. There was no significant difference between mannitol dehydrogenase activities in sporophore and mycelium. The results were consistent with a greater proportion of glucose oxidation occurring via the hexose monophosphate pathway in the sporophore than in the mycelium.

Toxin produced by Phytophthora cryptogea active on excised tobacco leaves

Abstract: A sterilized aqueous extract of mycelium of Phytophthora cryptogea, grown on a defined medium, caused water-soaking of excised tobacco leaves within 12 h, laminar collapse within 20 h, and extensiv...

Estimation of resistance of three wheat cultivars to Septoria tritici using a chemical method for determination of fungal mycelium

Abstract: A chemical method was employed to determine the mycelial content of wheat leaves infected by Septoria tritici Desm. A positive correlation was found between the latent period, incubation period, percentage of leaf area affected and the mycelial content of infected leaves. At certain times after inoculation the relative resistance of cultivars to S. tritici appeared to alter. The technique may be used to assess the reaction of wheat cultivars to this pathogen.

Kinetics of growth and chemical composition ofFusarium moniliforme cultivated on carob aqueous extract for microbial protein production

Abstract: The kinetics of growth and the chemical composition ofFusarium moniliforme cultivated on aqueous carob pod extract were investigated. The extract was adjusted to provide 0.5, 1.0, 2.0 and 4.0% carob sugars supplemented with inorganic salts at the ratio: carob sugar: NH4H2PO4: MgSO4.7H2O=1:0.6:0.012. The extract contained 16 mg tannic acid (Folin-Dennis) per g of carob sugar. The phase of vigorous growth was exponential. Tannins were not observed to depress growth. The maximum value of 0.22 h−1 for a specific growth rate corresponding to a generation time of 3.15 h was obtained when the fungus was cultivated on a 4% carob sugar medium. The dry mycelium produced per g of consumed carob sugar was then 0.515 g. The protein and purine content was affected by the composition of the growth medium. Protein values up to 37.7% true (Lowry) and 53.1% crude (NX6.25) of dry mycelium were recorded. Mean purine contents were 89 and 116 μmol/g, corresponding to nucleic acid levels of 5.7 and 7.5% for mycelium grown on 0.5 and 4.0% carob sugar respectively. These findings linked with those previously reported regarding the good appearance and nutritional quality ofF. moniliforme (Drouliscos et al., 1976) make this fungus worthy of consideration for the production of protein.

COMPOSITION OF THE MYCELIUM OF Penicillium roqueforti

Abstract: The proximate chemical and detailed lipid composition of the vegetative mycelium of the mold Penicillium roqueforti were determined. Maximum lipid accumulation in the mycelium of P. roqueforti occurred at a growth temperature of 25°C, and a culture age of 120 hr when mold cultures were grown in liquid submerged corn steep liquor/sucrose media. The dry mycelium consisted of 48.3, 37.8, 10.4 and 3.5% of carbohydrate, crude protein (N × 6.25), lipid and ash, respectively. The amino acid composition of the protein from P. roqueforti was excellent, being only slightly deficient in methionine. The levels of leucine, aspartic and glutamic acid residues were high. Neutral lipids were composed of triglycerides, 33.8%; diglycerides, 1.7%; free fatty acids, 8.1%; and nonsaponifiable material, 8.1% of the total lipids, respectively. Phospholipids comprised 35.3% and glycolipids 7.4% of the total lipids. Palmitic, stearic, oleic, and linoleic acids were the major fatty acid components of the total lipids of P. roqueforti mycelia.

Transmission of PsV-F and PsV-S Mycoviruses during Conidiogenesis of Penicillium stoloniferum

Abstract: SUMMARY: Levels of both fast and slow Penicillium stoloniferum virus (PsV-F and PsV-S) were evaluated in single conidial isolates of P stoloniferum NRRL5267 Approximately 7 % (3/43) of a random population of conidia from a culture of P stoloniferum contained no PsV-F, while other conidia produced cultures with various levels of PsV-F The greatest variation in PsV-F levels was observed in single conidial isolates from cultures that contained low to intermediate levels of virus, ie 11 to 25 E 1cm 260 units per g dry weight of mycelium The least variation was seen in isolates from a culture with a high PsV-F level (37 E 260 units per g dry weight of mycelium) Two of the original 43 single conidial isolates contained no detectable PsV-F or PsV-S Of the second-generation single conidial isolates from an original PsV-S+ PsV-F- isolate, 6 % failed to show detectable PsV-S PsV-F levels of cultures remained constant throughout a series of transfers when the inoculum was a mixture of conidia and mycelium The presence of PsV-F at different levels, or its complete absence, did not affect fungal biomass, conidium size, morphology or viability The results are discussed in terms of how conidiogenesis may influence the transmission or persistence of PsV-F and PsV-S during morphogenesis

Effects of temperature and inoculum concentration on infection of narcissus bulbs by Fusarium oxysporum f.sp. narcissi

Abstract: SUMMARY Chlamydospores of Fusarium oxysporum germinated, and mycelium grew on agar, at 10 but not 8°C. Numbers of chlamydospores needed to initiate disease suggest that the principal sources of infection are within the stock of bulbs and not the soil.

Cultivation medium for and culturing of basidiomycetes

Abstract: PURPOSE: To improve the efficiency for the growth and the proliferation of Basidiomycetes, to save the culturing time thereof, and to increase the yield of mycelium or fruit body of the Basidiomycetes, by the use of a medium comprising a specially treated wood material. COPYRIGHT: (C)1978,JPO&Japio

Respective role of cap and mycelium on stipe elongation of coprinus congregatus

Abstract: In developing fruit bodies of Coprinus congregatus Bull. ex Fr. the presence of the cap is necessary for complete stipe elongation until a late stage. Stipe elongation also depends on the presence of vegetative mycelium at the base of the fruit body. Dry weight of the stipe increases during the entire period of elongation. The concept of relative residual growth permits evaluation of the dependence of stipe on cap and vegetative mycelium at each stage of fruit body development. This dependence diminishes progressively as the fruit body approaches maturity, but is always detectable.

Effect of Amino Acids on Coremium Development in Penicillium claviforme

Abstract: Summary: Amino acids added to the growth medium stimulated development of coremium primordia in mycelium of Penicillium claviforme. Casein hydrolysate, l-asparagine, l-serine, l-glutamine, l-proline, l-hydroxyproline, l-glutamate and glycine accelerated development and also increased the final number of primordia per unit area of mycelium. A nearly linear relationship existed between the logarithm of casein hydrolysate concentration and the numbers of primordia developed, and a similar relationship was also shown with glutamate as nitrogen source. Mycelium developing from spores sown on agar plates showed some sites for coremium development within a few hours of germination, although most sites were not established until about 24 h later when the germlings had fused to form a network. At least 27 h exposure was required for amino acids to stimulate primordium development in 24 h-old mycelium. Cycloheximide, glucosamine and nystatin promoted primordium development at concentrations inhibiting hyphal growth; 2-deoxyglucose inhibited primordium formation. It was concluded that possible sites for coremia develop into primordia as a result of changes in nitrogen metabolism, and that local variations in the concentrations of certain amino acids or their metabolites may decide the pattern in which primordia form in the colony.

Tryptophansynthase in Phycomyces blakesleeanus, Teil II: Tryptophansynthaseaktivität des Pilzes in Abhängigkeit von Lichtbedingungen und vom Zinkgehalt des Kulturmediums

Abstract: Tryptophan synthase in Phycomyces blakesleeanus Part II: Activity of tryptophan synthase in Phycomyces blakesleeanus depending on the light and the content of zinc ions in the culture medium Five-day-old cultures of Phycomyces blakesleeanus show notice-able differences in the phenotype, depending on the culture conditions (permanent light, permanent dark, zinc deficiency, zinc sufficiency) and related to the distribution of tryptophan synthase activity between mycelium and sporangiophores Permanent light and the presence of zinc ions in the medium during culturing have an antagonistic influence on the tryptophan synthase The activity of the enzyme is being reduced in the sporangiophores and increased in the mycelium by the influence of light, while zinc ions in the culture medium increase the activity in the sporangiophores at simultaneous reduction in the mycelium The importance of tryptophan synthase and tryptophan for the development of the fungus in relation to the metabolism of indole acetic acid is discussed

α-mannosidase and mannanase of some wood-rotting fungi

Abstract: Cultivation media from 11 wood-rotting fungi contained α-mannosidase and mannanase activity. α-Mannosidase was studied in more detail inPhellinus abietis and mannanase was studied more intimately in basidiomycetesPhellinus abietis, Trametes sanguinea andPholiota aurivella. Suitable cultivation conditions and optimum conditions for the production of α-mannosidase and mannanase were determined. Both enzymes are constitutive; mannanase is extracellular, α-mannosidase was found in both mycelium and cultivation medium.