Showing papers on "Mycelium published in 1971"

Proposal of a New Genus, Gordona, for Slightly Acid-fast Organisms Occurring in Sputa of Patients With Pulmonary Disease and in Soil

Abstract: SUMMARY: A new genus Gordona has been proposed for slightly acid-fast organisms which occur in sputa of patients with pulmonary disease and in soil. This genus is considered to contain ‘Mycobacterium’ rhodochrous-like organisms. The genera Mycobacterium and Gordona are characterized by absence of mycelium and slight or strong acid-fastness. The genus Gordona shows characters intermediate between the genera Mycobacterium and Nocardia. It is distinguished from rapid-growing mycobacteria by its slight acid-fastness (weaker than Mycobacterium), absence of arylsulphatase activity at 2 weeks, ability to utilize sucrose as a sole carbon source and inability to utilize trimethylene diamine as a simultaneous nitrogen and carbon source. The genus is distinguished from nocardias by the absence of mycelium, ability to form acid from mannose, positive nitrate reduction and ability to utilize sucrose as a sole carbon source. It can be isolated from sputa of patients with lung cavities or bronchiectasis and from soil by prior treatment with alkali. The organisms are Gram-positive or variable; slightly acid-fast, that is, stained light pink or light violet by the Ziehl-Neelsen method; mycelium not formed; spores not formed; non-motile; aerobic; catalase-positive; oxidase-negative; acid formed from glucose by oxidation; growth occurs at 28° and 37° but not at 45°; growth at 2 to 3 days forming rough, reddish or pinkish colonies in air; occur as short rods; non-pathogenic for mice, rabbits, guinea pigs and chickens. Type species is Gordona bronchialis.

Studies on validamycins, new antibiotics. II. Production and biological properties of validamycins A and B.

Abstract: Streptomyces sp., strain No. T-7545 was found to produce new antibiotics, validamycins A and B that are effective for the control of sheath blight of rice plants. The validamycins exhibit no in vitro activity. A taxonomic study of strain No. T-7545 was carried out and it was characterized as follows: It forms gray to gray and yellow aerial mycelium, bright yellow to yellow ocher vegetative mycelium and faint, brownish yellow diffusible pigment, good growth and development of abundant aerial mycelium with the formation of coiled chains of spores at 25-45°C, and black moist areas in the aerial mycelium on certain media. As a result of comparison of strain No. T-7545 with known species, the name Streptomyces hygroscopicus WAKSMAN et HENRICI, 1948 var. limoneus nov. var. is proposed.

Chemical and genetical control of induction of monokaryotic fruiting bodies in Coprinus macrorhizus

Abstract: Fruiting-inducing substance (FIS), which is effective to induce fruiting bodies in monokaryotic mycelia of a strain of the Basidiomycete, Coprinus macrorhizus, has been detected in cell-free extracts of fruiting bodies and dikaryotic mycelia of C. macrorhizus itself and fruiting bodies of several other Basidiomycete species. Inducibility by FIS was controlled by genetic and environmental factors. Constitutive mutants which form monokaryotic fruiting bodies without addition of FIS were isolated. Fruiting bodies and monokaryotic mycelia of these mutants also contained FIS. FIS was stable to heat, acid and alkaline hydrolysis, and several enzymes degradating proteins and nucleic acids. Two fractions of FIS were obtained after Sephadex G-25 chromatography. One of them contained protein and the other appears to have similar chemical nature as adenosine-3′, 5′-monophosphate or adenosine-3′-monophosphate which were active to induce monokaryotic fruiting.

Phenoloxidase Activity and Fruiting Body Formation in Schizophyllum commune

Abstract: Studies of induced haploid fruiting in the Basidiomycete Schizophyllum commune suggested that polyphenoloxidase enzymes may participate in the formation of fruiting bodies. Reported inhibitors of phenoloxidases were found to affect both the activity of these enzymes and the fruiting response. Fertile mycelia were found to give a positive Bavendamm reaction in situ, and cell-free extracts from fertile mycelia exhibited polyphenoloxidase activity when studied spectrophotometrically. Sterile mycelia, on the other hand, were devoid of these activities. Various kinds of mutant homo- and dikaryotic mycelia were studied, and the results suggested a correlation between phenoloxidase activity and fruiting body formation in S. commune.

The relation of extracellular amylase, mycelium, and time, in some thermophilic and mesophilic Humicola species.

Abstract: All four fungi studied attained approximately the same dry weight of mycelium in starch-yeast extract medium. Only about one-fourth the amount of mycelia was produced in yeast extract alone (starch omitted). However, the initial growth rate ofH. grisea var.thermoidea was greater than the other three fungi. Extracellular amylase was produced by all four fungi, butH. lanuginosa produced 8 to 12 times as much as the other three. Maximum extracellular amylase was found before autolysis with these three fungi, but after autolysis withH. lanuginosa. Extracellular amylase was detected in YE medium (lacking starch), but in very low amounts (approximately one-eighth the amount observed as when starch was present). Increasing the amount of starch in the medium increased extracellular amylase. However, when the starch concentration was kept constant, increasing the concentration of yeast extract had no effect on extracellular amylase.

Fatty Acid and Sterol Composition of Mucor genevensis in Relation to Dimorphism and Anaerobic Growth

Abstract: Fatty acid and sterol content and composition were determined for the dimorphic mold, Mucor genevensis, grown under a variety of experimental conditions. Fatty acids account for 6 to 9% of the dry weight of aerobically grown mycelium, and 70 to 80% of these are unsaturated. The organism contains gamma-linolenic acid which is characteristic for Phycomycetes, and in sporangiospores this compound represents 40% of the total fatty acids. Of the sterols found in mycelium, 80% is ergosterol, and stigmasterol was positively identified as one of the minor components. In anaerobically grown yeastlike cells, sterol content is less than 10% of the level found in aerobically grown cells, and fatty acids amount to less than 2% of the dry weight. These fatty acids are predominantly short chain and less than 10% are unsaturated. Yeastlike cells obtained under aerobic conditions by growth in the presence of phenethyl alcohol have fatty acid and sterol compositions characteristic of aerobically grown mycelium. It is concluded that the dimorphology of the organism is not directly related to lipid composition.

Behaviour of Ophiobolus graminis on slides buried in soil in the presence or absence of wheat seedlings

Abstract: On slides buried in field soils, mycelial inoculum of Ophiobolus graminis produced hyphae, which grew towards wheat seedling roots, forming clumps of cells in the root hair region and infecting hairs before penetrating seminal root axes. Without roots few new hyphae grew, but phialospores (microconidia) were produced abundantly. Growth was similar using infected wheat roots as inoculum, except fewer and smaller clumps developed. Using infested debris from a wheat-field as inoculum, the amount of clump formation and root hair infection was negatively correlated with the size of the colonized host fragments and no phialospores developed. All clumps were ephemeral and lysed quickly after seminal axes were infected. Phialospores remained intact during 21 days' observation, but did not germinate. Mycelium labelled with fluorescent brightener confirmed that the observed growths were O. graminis . It is suggested that O. graminis has an ephemeral feeding stage before initial infection of an axis. The extent of this depends on the nutritional status of the original inoculum : inoculum with large food reserves can infect roots without extensive clump development and root hair infection. When there is no host stimulus, active mycelium with small food reserves produces phialospores, but slowly metabolizing mycelium in debris does not.

The axenic culture of Puccinia species from uredospores: experiments on nutrition and variation

Abstract: Eighteen isolates of Puccinia were compared for ability to grow as saprophytes. After incubation of uredospores until growth ceased, six isolates developed an extensive mycelium, nine isolates formed a limited mycelium, and three isolates produced only scant saprophytic hyphae.The following factors were tested for their effect on the growth of P. graminis tritici race 126 Anz 6,7: inoculation from different uredosori; mode of application of the inoculum; density of the inoculum; composition of the medium. Using a dense inoculum it was found that yeast extract and peptone may be replaced by aspartic acid and a sulphur amino acid such as cysteine, and that glucose, fructose, mannose, or mannitol will substitute for sucrose as principal carbon source. However, no medium or method of inoculation was found to be completely reliable. A study of thinly seeded cultures showed that although 20–80% of sporelings could initiate saprophytic growth, only 3–6% eventually formed macroscopically visible colonies. It was ...

Triterpeneglycosides as Inhibitors of Fungal Growth and Metabolism

Abstract: A venacin, the resistance factor in oat roots against Ophio-bolus graminis var. graminis, and a related triterpeneglycoside, aescin, induced a rapid release of K+ from mycelia of Opbio-bolus graminis and Neurospora crassa, suspended in phosphate buffer. N. crassa also released Mg2+ whereas no outflux of Mg2+ was found from O. graminis. The inhibitors induced a release of inorganic phosphate into acetate buffer from Neurospora crassa. The amount of inorganic phosphate in the mycelia decreased when O. graminis and N. crassa were treated with the inhibitors in phosphate buffer. In other media the inhibitors had weak or no effects on the ion contents of the mycelia. The effect of aescin was low in Aspergillus niger and nil in Pythium irregulare. However, high amounts of K+, Mg2+, and phosphate ions were lost to the medium when the mycelium of P. irregulare, washed with distilled water, was suspended in different buffers. The ions lost were reabsorbed during the experimental period. The leakage of ions indicates that the plasma membrane of the growth sensitive fungi is severely affected by the inhibitors, while a corresponding effect on the growth insensitive fungi does not take place.

Inorganic polyphosphates in the wheat stem rust fungus and in rust-infected wheat leaves

Abstract: Results presented in this paper establish the presence of inorganic polyphosphates in saprophytic cultures of the wheat stem rust fungus (Puccinia graminis tritici), and in non-infected and rust- infected primary leaves of wheat. Evidence for the presence of these compounds was based on acid-lability, non-adsorption to charcoal, metachromatic reaction with toluidine blue, paper chromatographic mobility and histochemical staining. Ten days after inoculation, rust-infected primary leaves of wheat contained eight times more inorganic polyphosphate than control leaves of the same age. Much of this polyphosphate was located in the stem rust uredospores. Further analysis of the uredospores revealed that approximately 90% of the cold acid-soluble phosphorus which was not adsorbed to charcoal was in the form of inorganic polyphosphate. The corresponding figure for the saprophytic rust mycelium was 80%. Rust-infected wheat leaves and saprophytic mycelium contained both high and low molecular weight polyphosphates. The low molecular weight polyphosphates were heterogeneous with respect to electrophoretic mobility on polyacrylamide gels. In contrast, the polyphosphates of non-infected wheat leaves were of low molecular weight only and were relatively homogeneous.

Assay of Fungal Mycelium in Grains of Barley, including the Use of the Fluorescent Antibody Technique for Individual Fungal Species

Abstract: The lemmas and paleas of individual barley grains were detached and the amount of fungal mycelium present was determined by direct microscopic observation. The area in which mycelium was present varied from 19·7 to 87·7% of the lemma, and from 44·2 to 92·8% of the palea. The total estimated length of mycelium observed varied from 19 to 177 cm. in individual grains. It is suggested that these lengths represented dry weights of mycelium of the order of 1·5 to 1·9 μg. in individual grains. The indirect fluorescent antibody technique was used to determine the extent of Penicillium cyclopium mycelium. The area in which this species, predominant in plate cultures, was present did not exceed 22·7% of the lemma, and no more than 17·2% of the palea. The results indicated that this technique is useful in the detection and estimation of individual species in barley grains and that it might be of use in other plant disease studies.

Two types of Pyruvate Kinase in Mucor rouxii

Abstract: Extracts of mycelium of Mucor rouxii have been shown to contain two forms of pyruvate kinase named Type I and II. They can be separated by DEAE-cellulose chromatography and by electrophoresis in polyacrylamide gel. Extracts from ungerminated sporangiospores or yeast-like cells contained only the Type I form. Pyruvate kinase Type II appears during aerobic germination of spores or during conversion of yeast-like cells to mycelium. Both pyruvate kinases are similar in their molecular weight, pH range of activity, Km with respect to substrates and their response to activators (Mn++ and fructose 1,6-diphosphate).

Carbon sources, growth, sclerotium formation and carbohydrate composition of Sclerotinia sclerotiorum

Abstract: Sclerotinia sclerotiorum (Lib.) D By. was grown in stationary liquid mineral-salts medium, pH 4.3, containing various carbon sources and the weight of mycelia and sclerotia was determined at regular intervals. When grown on various glucose concentrations (0–24 g of C/l), more sclerotia were produced at 8–12 g of C/l. Sclerotia were not usually formed in shake cultures. The ability of the fungus to use other carbon sources for growth and sclerotium formation was tested at 12 g of C/l in the stationary mineral-salts medium. The highest weights of mycelia and sclerotia occurred with raffinose, sucrose, maltose, lactose, d-mannose, d-glucose, d-fructose or l-arabinose. Good growth but decreased sclerotium production were found on cellobiose and d-xylose. Reduced or poor growth, a long lag period and few or no sclerotia occurred on trehalose, melibiose, l-sorbose, l-rhamnose, d-ribose, d-arabinose, l-xylose or 8 polyols. No growth was observed with erythritol or i-inositol. A combination of glucose plus trehalose or polyols resulted in increased growth and the formation of sclerotia. Organic acids supported little or no growth and no sclerotia were produced. Generally culture filtrates which supported growth and formation of sclerotia became acid (about pH 3.5). The pH of the culture filtrate usually increased slowly during the growth period when the fungus grew poorly and no sclerotia were formed. The alcoholsoluble sugars and polyols present in culture filtrates, mycelia and sclerotia were determined by paper and thin-layer chromatography. Regardless of the carbon source, mannitol was usually present in culture filtrates. The occurrence of other compounds in the filtrates depended on the carbon source. Trehalose, mannitol and usually small quantities of glucose or fructose were present in mycelia and sclerotia from all carbon sources. Galactitol or pentitols occurred in mycelia and sclerotia when the fungus grew on galactose and oligosaccharides containing galactose or the corresponding pentose, sugars. Acid hydrolyzates of the alcohol-insoluble fraction of mycelia or sclerotia contained glucose, smaller amounts of galactose and mannose and traces of ribose and rhamnose.

Production of Lytic Plaques of Viral Origin in Penicillium

Abstract: THE presence of virus particles in fungi is now established on the basis of observations in Agaricus (Psalliota) bisporus and in Penicillium stoloniferum2,3 and P. chrysogenum4. Viruses in A. bisporus cause several malformations of the fruiting body5 and some morphological variations of the colony in P. stoloniferum3. Small patches of white aerial mycelium have frequently been observed on the surface of fungi and we have confirmed this for P. citrinum and P. variabile grown on potato glucose agar at 24° C. When these organisms are grown on 18% lactose, 1% peptone, 2% agar, distilled water (pH 6·5) (medium A) at 24° C, lytic plaques are observed on the reverse of the patches of white aerial mycelium (Fig. 1a, b), which are morphologically similar to those produced by bacteriophages in bacteria and in streptomycetes. The mycelium taken from the centre of the lytic area consists of swollen hyphae, wholly lysed or with very little cytoplasm. Observation with the electron microscope, after fixation with phosphotungstate (PTA) at pH 7, has shown that the hyphae yield a large amount of virus particles (2 to 100 per field) as previously observed1–4. The particles have a hexagonal shape, with no tail and a diameter of 400–500 A.

Location and extent of fungal mycelium in grains of barley

Abstract: Cryostat sectioning and phenol-acetic-aniline blue staining was used in a detailed study of the location of the internal fungal mycelium in apparently healthy grains of barley plants. Hyphae were observed in the parenchyma layer of the lemma and palea which enclose the mature caryopsis, and within the pericarp layer of the caryopsis itself. No mycelium was observed in other parts of the grain. As assessment technique is described for the estimation of fungal mycelium present within individual grains.

The Heat Resistance of Some Thermophilic Fungi on Mushroom Compost

Abstract: In processing (composting) the horse manure-wheat straw mixture in which Agaricus bisporus (Lange) Imbach, the cu'tivated mushroom, is grown, high temperatures are obtained which are above the reported maxima for the thermophilic fungi. In addition, 42 hr after the start of phase II (6), high temperatures are induced by reducing ventilation into the room and admitting steam. This process is called pasteurization, and temperatures as high as 65-70 C may be attained. The heat resistance of the spores and mycelium of the thermophilic fungi that grow in the compost in phase II is unknown (2, 3, 7). Their ability to survive the pasteurization will determine whether they are able to resume growth in the later part of phase II, and possibly in later phases of the mushroom growing cycle. Therefore, the ability of a number of thermophiles growing on compost to resist exposure to various selected high temperatures was studied. The fungi were grown on compost for 48 hr so that their heat resistance, which would depend upon whether they had formed spores, the type of spore or resistant vegetative structures, would be similar to that developing during the actual composting process. The compost (moisture content 75%) was placed in test tubes (13 mm x 100 mm) to a depth of 6 cm. The tubes were capped with aluminum foil after the

Verticillium wilt of chrysanthemum: colonization of leaves in relation to symptom development

Abstract: The vascular system of leaves of chrysanthemum plants inoculated with Verticillium dahliae was invaded by mycelium before the appearance of visible wilt symptoms. After flower buds appeared a rapid rise in the number of propagules of fungus in the leaf was followed by a rise in severity of visible wilt symptom expression and conductivity of leaf exudate. Those portions of the leaf with the most advanced stages of wilt contained the greatest amounts of fungus. It is suggested that the mycelium within the leaf makes a significant contribution to the development of symptoms of wilt.

Synthesis of Macromolecules and Polyribosome Formation in Early Stages of Spore Germination in Fusarium solani

Abstract: SUMMARY: Net synthesis of protein and RNA in germinating macroconidia of Fusarium solani began at the time of appearance of germ tubes, RNA being formed first; net DNA synthesis began much later. Studies on precursor incorporation indicated that the ungerminated spore, at the time of its removal from the parent mycelium, had a low but real capacity to synthesize both RNA and protein. Leucine incorporation rose very rapidly to a maximum at about 40 min. after harvest; even in the time required for conventional washing and filtration, incorporation capacity increased threefold. Ultra-centrifuge profiles showed polysome peaks after 15 min. incubation; evidence from ribonuclease treatment was consistent with the existence of polysomes in the spore at the time of removal from the mycelium. Neither protein nor RNA synthesis required a complete medium, but DNA was synthesized only in a medium that supported germination.

Application of acrylamide gel electrophoresis of soluble fungal proteins to taxonomy of Verticillium species

Abstract: Soluble proteins extracted from the mycelium of five Verticillium species were separated by acrylamide gel electrophoresis. V, albo-atrum. V, dahliae, V. tricorpus, V. nigrescens and V. nubilum could be distinguished by their protein pattern even although both the pattern and intensity of the protein bands changed with age of culture.

The mechanism of mycelial strand induction in serpula lacrimans: a possible effect of nutrient distribution

Abstract: Summary Experiments were carried out on the conditions favouring strand formation in the mycelium of Serpula lacrimans. The mechanism of strand production proposed by Garrett and Butler (1960) was taken as a working hypothesis. Colonies of the fungus were grown on a liquid medium of a nutrient composition found previously to induce stranding. In one set of cultures this medium was renewed daily by slow perfusion of fresh medium through the culture vessels, continued over a 6-week period. In a parallel set of cultures the medium remained static and was not renewed over the same period. Strands formed only in these static cultures and not in the perfused ones. When the fungus was grown from a nutrient-rich food base over media at a range of lower concentrations it was found that there was an optimal lower concentration for strand formation. Another state of nutrient supply that favoured the formation of strands occurred when mycelium growing out from a food base over a non-nutrient medium encountered and began to colonize a fresh food base. This observation, first made on Helicobasidium purpureum by Valder (1958), was repeated using Serpula lacrimans and it was also shown by using 14C-labelled glucose that carbon was transported between old and new food bases. Further experiments using 14C as a tracer showed that there was a loss of substances containing carbon from intact hyphae and from strand-forming mycelium. The significance of these results is discussed, and it is suggested that to Garrett's original hypothesis might be added the proposition that nutrient leakage from older hyphae is part of the process of strand induction.

Synthesis of neomycin by washed mycelium of Streptomyces fradiae and some physiological considerations.

Abstract: Studies on the effects of different carbon sources on neomycin formation by washed cells ofStreptomyces fradiae 3535 indicate that they do not stimulate the antibiotic synthesis. The higher titer of neomycin in mineral salts medium is due to the fresh synthesis of neomycin and not merely due to release from the mycelium. Glucosamine andN-acetylglucosamine are stimulatory to neomycin production. The neomycin activity of the broth and the alkaline phosphatase level of the mycelium decrease on the addition of glucose to the medium. The metabolism of neomycin and neomycin phosphate is stimulated in the presence of glucose. Studies on changes in mycelial constituents during neomycin production show that during lysis there is loss of amino acids from the cell while the amino sugar and sugar content remain unaffected. In the medium where cells are resistant to lysis, mycelial total amino acid, amino sugar and sugar increase gradually and the growth phase is prolonged upto day 7 of fermentation.

Cell wall composition and "protoplast" formation of Geotrichum candidum.

Abstract: An inducible lytic enzyme complex from Streptomyces satsumaensis was capable of releasing spherical protoplast-like bodies from the mycelium of Geotrichum candidum. An analysis of this enzyme complex revealed the presence of chitinase, mannanase and laminaranase. Also a combination of chitinase and exolaminaranse from other sources could produce the “protoplasts” under standard conditions.

Pathogenicity of Fusarium oxysporum to Easter lily, narcissus and gladiolus

Abstract: SUMMARY Isolates of Fusarium oxysporum from roots, bulbs and stems of Easter lilies (Lilium longiflorum) differed widely in pathogenicity and also, apparently, in tissue specificity. Virulent isolates caused a typical basal rot and root rot (but not a wilt) in which the mycelium advanced intercellularly through the scales and basal plates. Mildly pathogenic isolates became established in mature or senescent outer scales, at first producing only superficial effects, but further growth of mycelium occurred as the outer scales died and sometimes continued until the dead tissues were permeated and chlamydospores were formed. The underlying scales were then colonized. The modes of pathogenicity and survival in Easter lily were compared with those of the F. oxysporum formae causing bulb rots of gladiolus and narcissus. It is suggested that advance of hyphae by penetration between the cells of the vascular parenchyma, which is common in isolates causing rots in bulbs and corms, represents a stage in the evolution of the truly vascular habit among fusaria.

Relationships among species of Verticillium: protein composition of spores and mycelium

Abstract: Buffer-soluble proteins extracted from six morphologically different isolates of Verticillium were separated by polyacrylamide gel-electrophoresis. Protein patterns from the six isolates were diffe...

Compartmentation and low temperature fluxes of potassium in mycelium of dendryphiella salina

Abstract: Summary Dendryphiella salina was grown at 21° C in two media, identical except that one contained potassium labelled with 42K. The cultures were transferred to 2° C, the fungus separated from the medium, the radioactive mycelium placed in the non-radioactive medium and the efflux of 42K measured. Under these conditions the rate of dry weight increase is reduced by at least 75%. The fungus behaves as a multicompartment system with regard to potassium with at least 75% of the ion being in the slowest-exchanging compartment. The efflux from this compartment into a medium containing 2.5 mM potassium is of the order of 0.14 p moles cm−2 sec−1, being at least doubled when 50 mM sodium is present. Addition of 10 mM calcium in the presence of sodium reduces the efflux to a value close to that obtained when sodium is absent.

Changes in activities of the embden-meyerhof-parnas and pentose phosphate pathways during the growth cycle of Aspergillus niger

Abstract: The specific activities of certain enzymes of the Embden-Meyerhof-Parnas (EMP) and pentose phosphate (PP) pathways varied in cultures of Aspergillus niger in relation to the stage of the growth cycle and the nature of the growth medium. At 24 h from spore inoculation the levels of PP pathway enzymes glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and transketolase were higher in extracts from non-sporulating than from sporulating mycelium. Correspondingly, the levels of most EMP pathway enzymes were higher in extracts from sporulating than from non-sporulating mycelium. These fluctuations in enzyme levels occurred well in advance of any morphological evidence of sporulation. At later stages of growth (48–96 h) the levels of the enzymes were similar in extracts from both types of mycelium. Radiorespirometric patterns for the oxidation of specifically labelled [14C] glucose implied that the EMP and PP pathways were active in both types of mycelium. The contribution of the PP pathway was highest in young non-sporulating mycelium whereas the contribution of the EMP pathway was highest in sporulating mycelium of corresponding age.