Showing papers on "Mycelium published in 1980"
TL;DR: The results suggest that the barriers to mycorrhizal infection in ‘non-hosts’ are intrinsic and more probably related to characteristics of the root cortex or epidermis than to any infection-inhibiting factors that might be released in root exudates.
Abstract: Summary
Mycorrhizal infections formed by different endophytes were examined in 10 crop species grown separately and in pairs in sterilized and unsterile soils. No infection was observed in cabbage, kale, rape or swede (in the supposedly non-mycorrhizal family Cruciferae) and only traces were seen in sugar beet (supposedly non-mycorrhizal Chenopodiaceae) when these plants were grown alone. However, slight (< 5 %) infection (cortical mycelium and vesicles, but no arbuscules) developed in some when a mycorrhizal host plant was present and there were many clumps of endophyte mycelium on their root surfaces, usually attached to entry points which had often aborted. Glomus fasciculatus‘E3’ was a more infective endophyte than Gigaspora margarita. Infection was usually well developed in the host plants barley, lettuce, maize, potato and onion. It was depressed only in a few pairs but no more by the presence of a ‘non-host’ plant than by a host plant. The results suggest that the barriers to mycorrhizal infection in ‘non-hosts’ are intrinsic and more probably related to characteristics of the root cortex or epidermis than to any infection-inhibiting factors that might be released in root exudates.
165 citations
TL;DR: The life cycle of C. perniciosa is divided into two phases which are separated morphologically, genetically and physiologically: the biotrophic or parasitic, monokaryotic phase and the necrotrophic or saprophytic, dikaryoticphase, and the fungus is now classified as a hemibiotroph.
Abstract: Basidiospores of Crinipellis perniciosa (Stahel) Singer germinated rapidly in water and on standard agar media to produce a fine, hyaline, binucleate mycelium 1.5-3 μm diam, with clamp-connexions; the secondary or dikaryotic mycelium. White to cream, fast-growing, regular, cotton-like colonies were formed on agar. The primary mycelium was short-lived and dikaryotization occurred within 24–48 h. Basidiospores on vigorous cocoa callus tissues germinated slowly with short, abnormally swollen germ-tubes giving rise either to thickwalled chlamydospores or to a grossly swollen flexuous, hyaline to brown, uninucleate mycelium 5–20 μm diam with dense granular cytoplasm. Characteristic slow-growing, cerebriform colonies were irregularly formed on agar surrounding the callus. A similar, although less swollen, mycelium was observed intercellularly in infected green cocoa stems (brooms) and pods. Dikaryotization occurred when active callus or plant growth declined, and in old callus cultures and dead brooms the tissues were colonized, both inter- and intracellularly, by secondary mycelium. The primary mycelium became thick-walled and devoid of contents. The life cycle of C. perniciosa is divided into two phases which are separated morphologically, genetically and physiologically: the biotrophic or parasitic, monokaryotic phase and the necrotrophic or saprophytic, dikaryotic phase. The fungus is now classified as a hemibiotroph.
98 citations
TL;DR: Cell-free culture filtrates, mycelium extracts and cell walls of Cladosporium fulvum contained high molecular weight components which elicited rishitin accumulation in tomato fruit tissue, and the rishi tin-inducing activity of CFE, MEE and CWE was sensitive to NaIO 4 and also to NaOH, which suggest that the elicitors are glycoproteins.
Abstract: Cell-free culture filtrates, mycelium extracts and cell walls of Cladosporium fulvum (syn. Fulvia fulva ) contained high molecular weight components which elicited rishitin accumulation in tomato fruit tissue. Elicitors from mycelium extracts (MEE) and cell walls (CWE) appeared to be 5 to 10 times as active as those isolated from culture filtrates (CFE). Elicitors isolated from two races of Cladosporium fulvum were not host-specific. Of the four non-hosts of Cladosporium fulvum which were assayed for phytoalexin accumulation after treatment with elicitor, pea and soybean reacted by accumulation of pisatin and glyceollin, respectively, while under the conditions used potato and jack bean did not accumulate rishitin and medicarpin, respectively. The rishi tin-inducing activity of CFE, MEE and CWE was sensitive to NaIO 4 , α-mannosidase, Pronase, Proteinase K and also to NaOH, which suggest that the elicitors are glycoproteins. The rishitin-inducing activity of CFE was not bound to DEAE-Sephadex and could be purified threefold by chromatography on Con A-Sepharose 4B. CFE contained mainly glucose and some mannose, galactose and protein. MEE and CWE contained 5 to 10 times more mannose, galactose and protein than CFE. The protein part of all elicitors was especially rich in asparagine/aspartic acid, threonine, serine, gluta-mine/glutamic acid and proline.
94 citations
TL;DR: Three species of aquatic fungi supported the growth of the freshwater shrimp and showed that the metal can be transferred from aquatic fungi to G. pulex, the first step in a food chain involving freshwater fish and higher organisms.
68 citations
TL;DR: The commencement of pullulan excretion, which has been associated with blastospore production in the early phases of the growth cycle, probably arises through some stimulation concurrent with, though not necessarily identical to, the initiation of spore formation.
Abstract: The polymorphic fungus Aureobasidium pullulans has been fractionated into mycelium and single cells at three points in the growth cycle approximately corresponding to early, middle and late exponential phases. The ability of cells to divert assimilated glucose to form the extracellular polysaccharide pullulan varies throughout the cycle; the spores are the major source of polysaccharide, although the hyphae are also capable of producing it. Thus, the commencement of pullulan excretion, which has been associated with blastospore production in the early phases of the growth cycle, probably arises through some stimulation concurrent with, though not necessarily identical to, the initiation of spore formation.
66 citations
TL;DR: Two strains are suggested, one forming yeasts and one forming true mycelium in low-sulfate medium at 37 degrees C, thus providing controls for both strain variation and for molecular changes induced by environmental change but unrelated to morphogenesis.
Abstract: A low-sulfate synthetic medium was developed in which pure cultures of yeast- and mycelial-phase Candida albicans could be cultivated for investigations of the molecular biology of dimorphism. The medium contained ammonium ions, phosphate buffer, salts, glucose, and biotin. Morphogenesis was found to be dependent upon the strain of C. albicans. Of six strains tested in the low-sulfate medium at 37 degrees C, three formed mixed cultures of yeasts, true mycelium and pseudomycelium, two formed pure cultures of true mycelium, and one maintained yeast growth. All six strains produced pure cultures of yeasts at 24 degrees C. The buffering capacity of the medium maintained the pH at 6.9 even at high-density cell growth. The low concentration of sulfate and the absence of amino acids in the medium provided conditions in which to radiolabel cellular constituents with [35S]sulfate. For molecular investigations, the use of two strains is suggested, one forming yeasts and one forming true mycelium in low-sulfate medium at 37 degrees C, thus providing controls for both strain variation and for molecular changes induced by environmental change but unrelated to morphogenesis.
64 citations
TL;DR: In this paper, the authors classified the Ceratocystis ulmi isolates with respect to their ability to produce cerato-ulmin (CU) and synnemata, their radial growth, mycelial habit, and pathogenicity.
Abstract: Forty-seven isolates of Ceratocystis ulmi collected from Canada, the United States, the United Kingdom, France, the Netherlands, and Iran were classified with respect to their ability to produce cerato-ulmin (CU) and synnemata, their radial growth, mycelial habit, and pathogenicity.Twenty-nine isolates clearly produced CU in a measurable quantity while 18 isolates produced it only in trace quantities. In general, the former produced fluffy mycelium and were active in synnemata formation. They were aggressive in pathogenicity with one exception. The latter group of isolates generally produced waxy, yeastlike mycelium and formed very few synnemata. They were all nonaggressive in pathogenicity. Radial growth was generally higher among the isolates that produced CU in larger quantities than among those producing CU in trace quantities. The relationship between CU production and pathogenicity affords a method for estimating isolate pathogenicity without the need for host inoculation.
58 citations
TL;DR: Microscopic observation showed that Micrococcus luteus cells were being physically destroyed by bacterial predators in the soil, and two predators were responsible for the initial, main attack, and they were isolated.
Abstract: Micrococcus luteus cells died relatively rapidly when they were added to natural soil. Microscopic observation showed that the cells were being physically destroyed by bacterial predators in the soil. Two of these predators were responsible for the initial, main attack, and they were isolated. The isolates on laboratory media lysed M. luteus cells in a manner similar to the attacks that occurred in soil. Neither predator was obligate, however, nor were they nutritionally fastidious. One of these bacteria produced mycelium and conidia. Under nutritionally poor conditions it used slender filaments of mycelium to seek out host cells. It had at least some of the characteristics of a Streptoverticillium species. The other bacterium was a short, gram-negative rod that did not easily fit into any of the known groups of gram-negative bacteria. It attached to host cells, but its mechanism of lysing these cells is not known.
54 citations
TL;DR: Data suggest that some strains of these common filamentous phylloplane fungi are able to behave as weak parasites on herbaceous tissues and the use of fungicides which restrict their activity may result in yield increases over and above those attributed to the control of other, established pathogens.
Abstract: Phaseolus leaves were inoculated with conidia of Alternaria alternata, Cladosporium cladosporioides and C. herbarum. Plants were incubated in growth rooms at high humidity. Using light microscopy and cultural techniques it was shown that several of the isolates of all three species were able to penetrate into leaves via stomata. With many isolates most infections remained localized in the substomatal cavity. In other isolates, especially of Alternaria, a more extensive, intercellular mycelium developed. A few isolates also caused host mesophyll cells to become necrotic. These parasitic activities were correlated with an accelerated loss of chlorophyll from infected leaves and an increase in their levels of ribonuclease. These data suggest that some strains of these common filamentous phylloplane fungi are able to behave as weak parasites on herbaceous tissues. The use of fungicides which restrict their activity may result in yield increases over and above those attributed to the control of other, established pathogens.
48 citations
TL;DR: Its direct involvement in a genetically programed senescence is confirmed and its development as a vector for transfer of genetic information in eukaryotes can be undertaken.
Abstract: In the ascomycete Podospora anserina senescence through strain aging is under nucleo-cytoplasmic control and inducible in juvenile mycelia by an ‘infective principle’ transferred after cytoplasmic contact via anastomoses. A specific DNA called plasmid-like (pl) DNA, present exclusively in aging mycelia, was found to be identical with this ‘infective principle’, since it was possible to transform juvenile protoplasts to senescence by using purified p1DNA. Therefore a specific function may be attributed to this ccc DNA. Its direct involvement in a genetically programed senescence is confirmed and its development as a vector for transfer of genetic information in eukaryotes can be undertaken.
41 citations
TL;DR: Mycolaminarans are the storage polysaccharides in mycelium, sporangia, zoospores, cysts, and chlamydospores of diverse species of Phytophthora, and there is abundant synthesis and storage of mycolaminaran which are subsequently utilized for the formation of asexual and sexual sporulating structures.
TL;DR: A significant stimulation of incorporation of constituent amino acids into ergotamine and ergocryptine occurred when d-lysergic acid was added to protoplasts and mycelium.
Abstract: Protoplasts of Claviceps purpurea (ATCC 20102) were prepared in 0.8 m-sucrose containing 10 mm-CaCl2 and 10 mm-MgCl2. Protoplasts could revert to the filamentous state but not after treatment with water. Most of the protoplasts (about 80%) were highly vacuolated and these were separated from the non-vacuolated protoplasts and cell debris on the basis of their low density. Only the vacuolated protoplasts were able to synthesize ergotamine and ergocryptine de novo. Protoplasts were about 50% less active than the control mycelium. The control mycelium was more active in the uptake of labelled precursors than both protoplasts and freshly harvested mycelium. In the amino acid pool of protoplasts, alanine was present in a concentration which exceeded that of proline by a factor of six and that of phenylalanine by a factor of 100. This finding is consistent with the incorporation ratios of these amino acids into ergotamine when isotope dilution of the added radiolabel is considered. A significant stimulation of incorporation of constituent amino acids into ergotamine and ergocryptine occurred when d-lysergic acid was added to protoplasts and mycelium.
TL;DR: Citreomontanin, a new polyene 2-pyrone was isolated from the mycelium of P. pedemontanum based upon spectral data, and was assigned the structure: (all- E )-4-methoxy-5-methyl-6-(7,9,11- trimethyl-1,3,5,7,8-tridecahexaenyl)-2 H -pyran-2-one.
TL;DR: Citreopyrone isolated from the mycelium of Penicillium citreo-viride B has been found to be 5-crotonoyl-4-methoxy-6-methyl-2-pyrone as discussed by the authors.
TL;DR: Using straw columns colonized by the lignocellulytic fungus Pleurotus cornucopiae, translocation of 109Cd and 203Hg in the substrate mycelium complex and via the substrate-mycelium mixture into the fruiting bodies was studied.
Abstract: Using straw columns colonized by the lignocellulytic fungus Pleurotus cornucopiae, translocation of 109Cd and 203Hg in the substrate-mycelium complex and via the substrate-mycelium complex into the fruiting bodies was studied. The translocation patterns generated were metal specific and were influenced by the temperature and the physiological conditions of the mycelium (‘growing’ mycelium, ‘established’ mycelium, reproductive stage). Under all conditions, generally more mercury than cadmium was translocated. In ‘growing’ mycelia, for instance, an average of about seven times more mercury than cadmium was translocated. Translocation was greatly enhanced, when fruiting bodies were present. Up to 7% and 20% (average: 3.5% and 12%) of the applied cadmium and mercury, respectively, were found in the fruiting bodies. In ‘old’ columns bearing fruiting bodies (colonized for more than 50 days by the fungus) considerably more heavy metal (up to 45% of the applied radioactivity) was released from the point of application than in younger columns. With one exception, no substantial differences in the translocation patterns of the label in relation to the direction of mycelial growth could be detected.
TL;DR: In this paper, it was concluded that distinct kynureninase ( l -kynurenine hydrolase, EC 3.7.1.3) and hydroxykynuranine enzymes are produced by this organism.
TL;DR: Transmission was obtained from a two-year-old seed sample contaminated with oospores and from mycelium, and the significance of the results with particular reference to survival of inocula, development of epidemics and quarantine implications in international movement of germplasm are discussed.
Abstract: Sclerospora graminicola (Sacc.) Schroet. inoculum may be present in pearl millet seed either as oospores externally or in the form of dormant mycelium internally. Oospore inoculum was detected by using the washing method, and mycelial infection by the modified embryo count procedure. Fifty-nine seed samples out of ninety-three obtained from different sources were found contaminated with oospores whose viability was checked by the tetrazolium test. Percentage of viable spores ranged from 5.5 to 20.2. Forty-three samples showed mycelial infection of 0.1–7.5 Per cent in various parts of the seed. Seeds from healthy-looking plants are not necessarily pathogen-free. Transmission was obtained from a two-year-old seed sample contaminated with oospores and from mycelium. The significance of the results with particular reference to survival of inocula, development of epidemics and quarantine implications in international movement of germplasm are discussed.
TL;DR: With the exception of dikaryotization, the complete life-cycle of Ustilago esculenta occurred on potato dextrose agar in culture and an aqueous extract from culms of the host plant supported growth of sporidia and mycelium that was similar, or superior, to that on synthetic media.
Abstract: SUMMARY
With the exception of dikaryotization, the complete life-cycle of Ustilago esculenta occurred on potato dextrose agar in culture. In liquid synthetic media, the maximum dry wt of sporidia was reached in 7 days at 27°C compared with 20 days for mycelium. The sporidia were hetero-trophic for thiamine but not for biotin; the mycelium required neither vitamin. Mannitol supported the best growth of sporidia but only poor growth of mycelium; both stages grew well on fructose, glucose and sucrose. At suitable dilutions, an aqueous extract from culms of the host plant supported growth of sporidia and mycelium that was similar, or superior, to that on synthetic media. The implications of these results for the host-parasite combination are discussed.
TL;DR: Phenylthiocarbamide inhibits polyphenol oxidase activity in the plant, resulting in inhibition of fungal attack, and polymerizes the inhibitory plant phenols and neutralizes their effects.
Abstract: The relationship betweenBotrytis allii and onion bulbs was studied in the greenhouse and the field. Germinating conidia or growing mycelium in nutrient solution, water, or in the plant tissue secreted pectinases and polyphenol oxidase. These pectinases were found to be inhibited by phenol compounds and their low oxidation products but not by polyphenols. Pretreatment of onion bulbs or seedlings with catechol (O-dihydroxybenzene), catechol + tannic acid, or phenyl-thiocarbamide increased the plant concentrations of phenols and decreased the disease incidence. Fungal polyphenol oxidase polymerizes the inhibitory plant phenols and neutralizes their effects. Phenylthiocarbamide inhibits polyphenol oxidase activity in the plant, resulting in inhibition of fungal attack.
TL;DR: Mycelium of the pea pathogen Fusarium oxysporum f.
Abstract: Mycelium of the pea pathogen Fusarium oxysporum f. sp. pisi, pregrown in a medium without pisatin, readily degraded [14C]-pisatin. The first degradative step involved demethylation of the methoxyl group at C-3. The metabolite produced, 6a-hydroxy-inermin, was decomposed by reductive opening of the dihydrofuran ring, giving rise to 3-hydroxy-inermin-isoflavan. The isoflavan was broken down further, with a substantial loss of radioactivity, apparently because of production of volatile compounds such as CO2. Experiments with [14C]-6a-hydroxy-inermin substantiated this metabolic pathway. Mycelium of the non-pea pathogen Fusarium oxysporum f. sp. lycopersici, pregrown under similar conditions, accumulated pisatin but not 6a-hydroxy-inermin. Neither of the two compounds was degraded by this fungus.
TL;DR: When Serpula lacrimans grows over a non-nutrient, non-absorbant surface, droplet size can be reduced by severing the hyphae or applying 10 −4 mol 1 −1 sodium azide, 2 molal sucrose, or 1 molal potassium chloride to mycelium which is growing on the agar food base.
Abstract: When Serpula lacrimans grows over a non-nutrient, non-absorbant surface, droplets are produced in the 1 mm margin of the colony, mainly at hyphal tips. Tips may grow through droplets or become trapped in them. Sometimes tips burst. The rate of increase in droplet size can be reduced by severing the hyphae or applying 10 −4 mol 1 −1 sodium azide, 2 molal sucrose, or 1 molal potassium chloride to mycelium which is growing on the agar food base. The observations are discussed in terms of a pressure driven flow of fluid along the hyphae.
TL;DR: Patters of DIFFUSIBILITY of LIGNin and CARBOHYDRATE DEGRADING systems in WOOD-ROTTING FUNGI S. L. Rosenberg Septebmer 1979 is presented.
Abstract: SUMMARY In an attempt to identify organisms that produce diffusible lignindegrading systems, a culturing apparatus was constructed which contained two compartments separated by a bacteriological membrane filter. Lignindegrading fungi were grown with lignocellulose in one compartment, and diffusion channels were maintained through the membrane to sterile lignocellulose in the adjoining compartment. For the fungi tested both lignin and carbohydrate were degraded when the mycelium and the substrate were in physical contact, but only carbohydrate was degraded significantly in the adjoining compartment containing sterile lignocellulose. Two organisms, Coriolus versicolor and Trichoderma reesei QM 9414 displayed slight diffusible lignin-degrading activity. Some fungi produced more diffusible carbohydrate-degrading activity than others.
TL;DR: Experiments on the growth response to different vitamins showed that S. rolfsii produced sclerotia even on the medium lacking vitamins; the best harvest was obtained on themedium containing ascorbic acid.
Abstract: Growth requirements of Sclerotium rolfsii Sacc. were studied. Sclerotia developed on solid media and primordia started forming when the entire surface of the media in the culture plates was covered with mycelia. The optimal temperature for sclerotium formation varied between 20 and 37 °C. A wide range of carbon sources stimulated the formation of sclerotia, glucose clearly being the most effective. Sclerotia failed to form when a carbon source was absent from the medium. Sclerotia developed in the presence of all the nitrogen sources tested; the highest yield was obtained on (NH4)2SO4 and poorest on L-lysine. Experiments on the growth response to different vitamins showed that S. rolfsii produced sclerotia even on the medium lacking vitamins; the best harvest was obtained on the medium containing ascorbic acid. Media lacking potassium, magnesium, calcium, and sodium supported a good growth of mycelium, but sclerotia failed to form in the medium lacking potassium.
TL;DR: A general method is available for examining biochemical pathways with mutants accumulating intermediates unable to cross the cell wall barrier for penicillin biosynthetic pathway examination.
Abstract: Summary: Mycelia from four mutants of Aspergillus nidulans impaired in penicillin production at separate genetic loci were treated with an enzyme complex capable of lysing cell walls, then mixed in all possible paired combinations and grown in osmotically buffered penicillin production media, containing 2-deoxyglucose and an unrefined mixture of polyoxins to prevent cell wall regeneration. The culture filtrates were assayed after 6 d and significant penicillin yields were observed in four of the six possible combinations. None of these pairs produced penicillin when grown together as normal mycelium, suggesting that intermediates of the penicillin biosynthetic pathway unable to diffuse from untreated mycelium could do so from enzyme-treated mycelium when cell wall regeneration was inhibited. A general method is thus available for examining biochemical pathways with mutants accumulating intermediates unable to cross the cell wall barrier.
Journal Article•
TL;DR: Protoplasts have been prepared from the mycelium of Aspergillus funigatus, using a lytic enzyme mixture from Trichoderma harzianum, and electron micrographs showed the preparations to be free of cell-wall.
Abstract: Protoplasts have been prepared from the mycelium of Aspergillus funigatus, using a lytic enzyme mixture from Trichoderma harzianum. A variety of experimental conditions were investigated in order to achieve optimal conditions for protoplast production. Electron micrographs showed the preparations to be free of cell-wall. Material obtained by this procedure can be used as a source of cytoplasmic antigens for further analysis.
TL;DR: Hyphae of Geotrichum candidum Lk ex Pers have similar extension rates and cell dimensions when grown either in steady-state glucose-limited chemostat culture or on solid media with low initial glucose concentrations.
Abstract: Hyphae of Geotrichum candidum Lk ex Pers. have similar extension rates and cell dimensions when grown either in steady-state glucose-limited chemostat culture or on solid media with low initial glucose concentrations. In both methods of culture the mycelium is undifferentiated and hyphal development is incomplete. In liquid media which permit full hyphal development there is a recurrent cycle of development in which each apical cell branches dichotomously when five or more nonapical cells have been produced. During each cycle there is a gradual increase in diameter and volume of the apical cell and each successive non-apical cell produced is wider and of greater volume. The mycelium is undifferentiated. The effect of temperature on cell dimensions and hyphal development is discussed for chemostat culture, batch liquid culture and culture on solid media. In most cases an increase in temperature is associated with a decrease in hyphal diameter and cell volume.
TL;DR: Serpula lacrimans can produce under certain conditions surface mycelia which grows from discrete points on and at a markedly faster rate than the parent mycelium, similar to flushing and to strand formation; all are stimulated by a change to less favourable growth conditions.
Abstract: Serpula lacrimans can produce under certain conditions surface mycelium which grows from discrete points on and at a markedly faster rate than the parent mycelium. The difference in growth rates is maintained after subculturing on to fresh medium of the same composition. The two types of mycelia differ in pigment production and response to staling conditions. Mycelia with or without clamp connexions exhibit the phenomenon. It appears to be different from true sectoring, since the mycelium undergoes some differentiation but not apparently genetic change. The phenomenon is termed point growth and is similar to flushing and to strand formation; all are stimulated by a change to less favourable growth conditions.
TL;DR: A water-soluble polysaccharide, D-II with marked antitumor activity was isolated from the cultured mycelium of Coriolus versicolor and proposed that it is composed of a unit structure of four D-glucose residues, and is a glucan consisting of beta-D-1,3-linked main chain.
TL;DR: It is demonstrated that the known long persistence of P. fragariae in field soils cannot be as mycelia but must be by oospores.
Abstract: Pieces of mono-filament nylon cloth colonized by Phytophthora fragariae were buried in autoclaved and untreated soil at three moisture contents at 3°, 15° and 30 °C. They were recovered at intervals and tested for their ability to infect bait plants and for the production of sporangia when irrigated with calcium nitrate solution. Infectivity persisted longest in autoclaved moist soil held at 3° where it was still detectable after burial for 1 year. It declined most rapidly in untreated soil at 15° and 30°, not being detectable in any treatment combination after 63 days, the rapid loss of infectivity being coincidental with the disappearance of mycelium from the material. By contrast, naturally infested soil stored moist at 15° remained infective for 8 months. These results demonstrate that the known long persistence of P. fragariae in field soils cannot be as mycelia but must be by oospores.