Showing papers on "Mycelium published in 1987"
TL;DR: An actinomycete, strain C-38,383, was selected in a screening program for the isolation of novel antitumor agents and a yellow crystalline product was isolated from the mycelium and was found to have activity against P388 leukemia, L1210 leukemia and B16 melanoma implanted in mice.
Abstract: An actinomycete, strain C-38,383, was selected in a screening program for the isolation of novel antitumor agents. A yellow crystalline product, named rebeccamycin, was isolated from the mycelium and was found to have activity against P388 leukemia, L1210 leukemia and B16 melanoma implanted in mice. Rebeccamycin inhibits the growth of human lung adenocarcinoma cells (A549) and produces single-strand breaks in the DNA of these cells. No DNA-protein cross-links were detected. A related antibiotic, staurosporine, is produced by Streptomyces staurosporeus and Streptomyces actuosus. Strain C-38,383 was found to resemble closely strains of Nocardia aerocolonigenes recently renamed Saccharothrix aerocolonigenes. A strain selection isolate without aerial mycelium, C-38,383-RK-1, failed to produce rebeccamycin while a strain with aerial mycelium, C-38,383-RK-2, was found to be a suitable strain for production. A description of the producing strain is presented and its taxonomic position is reviewed. A fermentor containing 37 liters of production medium gave a rebeccamycin yield of 663 mg/liter after 204 hours of incubation with strain C-38,383-RK-2.
233 citations
TL;DR: Allosamidin, a novel insect chitinase inhibitor, was isolated from the mycelium of Streptomyces sp.
Abstract: Allosamidin, a novel insect chitinase inhibitor, was isolated from the mycelium of Streptomyces sp. It showed strong inhibitory activity against the chitinases of the silkworm, Bombyx mori, in vitro, and also insecticidal activity by preventing its ecdysis in vivo.
205 citations
TL;DR: In this article, it was shown that oxalic acid produced by an isolate of the mycorrhizal fungus Paxillus involutus (Batsch. ex Fr.) in still broth culture was assayed using high-performance liquid chromatography.
Abstract: Summary
Oxalic acid produced by an isolate of the mycorrhizal fungus Paxillus involutus (Batsch. ex Fr.) Fr. in still broth culture was assayed using high-performance liquid chromatography. Production of oxalic acid per unit of mycelium was influenced by nitrogen source and concentrations of exogenous calcium and bicarbonate ions. Nitrate-grown mycelia produced large quantities of oxalic acid; ammonium-grown mycelia produced small quantities regardless of what other ions were present. Calcium concentrations between 10 and 50 meq 1−1 slightly enhanced oxalic acid production in the presence of nitrate; concentrations between 250 and 500 meq 1−1 depressed production. Small additions of bicarbonate ions substantially increased oxalic acids production when nitrate was present. When calcium was present, most of the oxalic acid was associated with the mycelium, probably as calcium oxalate. In the absence of calcium, most of the oxalic acid occurred free in the culture medium. It is concluded that in calcareous soils, bicarbonate and nitrate are more important than calcium in stimulating oxalate production. The significance and underlying mechanisms of oxalate production are discussed.
149 citations
TL;DR: Ectomycorrhizal mycelial systems were grown in unsterile soil using specially designed growth chambers, and the respiratory activity of the mycelium was measured before and after its excision from the host roots.
Abstract: Ectomycorrhizal mycelial systems were grown in unsterile soil using specially designed growth chambers, and the respiratory activity of the mycelium was measured before and after its excision from the host roots. Approximately 30% of the total respiration in the intact system was attributable to the mycorrhizal mycelium in the soil. Severance of mycelial connections at the roots lead to a greater than 50% decrease in respiration rate within 24 h. This decline was much more rapid than that of root respiration rate which occurred when the shoot was excised from the intact system. The implications of these findings for the carbon balance and microbial ecology of forest systems are discussed.
116 citations
TL;DR: For any single growth medium, ergosterol content of mycelium was less variable with mycelial age than has been previously found for glucosamine, and there was evidence that green-microalgal ergostol content might not be negligible in some decomposition systems.
Abstract: Species of the ascomycete genera Phaeosphaeria, Leptosphaeria, and Buergenerula from the Spartina alterniflora decomposition system were analyzed for ergosterol content of their mycelium. Bacterial and algal members of the system were also tested. A standard laboratory liquid medium, a complex, semi-natural liquid medium, and a semi-natural solid medium were used to grow the microorganisms. Ergosterol contents of fungal mycelium ranged from 1.9-2.5 mg g 'dry organic mass in the standard medium, and were 3.4-16.4 mg g- ' in the semi-natural liquid medium. For any single growth medium, ergosterol content of mycelium was less variable with mycelial age than has been previously found for glucosamine. For Leptosphaeria obiones, ergosterol content in solid medium was estimated to be similar to that in semi-natural liquid, but for Phaeosphaeria typharum, solid medium yielded much higher (x 5) ergosterol estimates, possibly due to underestimated mycelial mass. Partial mycelial autolysis led to low estimates of ergosterol content (1.1 mg-g-' dry organic). Bacteria had negligible ergosterol contents, but there was evidence that green-microalgal ergosterol content might not be negligible in some decomposition systems.
115 citations
TL;DR: The ectomycorrhizal fungus Hebeloma cylindrosporum Romagnési produced sporulating fruit bodies under axenic conditions on a synthetic medium when cultivated with its usual host plant Pinus pinaster (Sol.), and was found to be capable of germinating.
Abstract: Summary
The ectomycorrhizal fungus Hebeloma cylindrosporum Romagnesi produced sporulating fruit bodies under axenic conditions on a synthetic medium when cultivated with its usual host plant Pinus pinaster (Sol.). In the absence of the host plant, H. cylindrosporum only formed primordia or immature fruit bodies. In 11 Erlenmeyer flasks, the fungal fruiting started about one and half months after the inoculation of one-month-old P. pinaster plants by the mycelium of H. cylindrosporum, and a total of 144 fruit bodies appeared in 45 flasks during a 9.5-month fruiting period. At 18 °C, the mean number of basidiomes developed per flask was about 3–5. A thermal shock of ± 6 °C for 5 d did not significantly affect the mean number of basidiomes per flask but modified the time course of their rate of formation. Spores were collected from the fruit bodies and were found to be capable of germinating.
111 citations
109 citations
TL;DR: The mating system in Epichloe typhina is indicated to involve simple bipolar heterothallism, and the endophyte reduces the fitness of infected individuals of A. tenuis and D. glomerata, but it does not appear to substantially reduce fitness ofinfected individuals of E. canadensis.
Abstract: Experiments conducted indicate the mating system in Epichloe typhina to involve simple bipolar heterothallism. Perithecia were formed when condia were transferred to a compatible stroma. Perithecial development followed the growth of mycelium over the surface of the stroma. The perithecial stroma consisted of two layers: an inner layer composed of the original mycelium of the conidial stroma and an outer layer that appears to be composed of mycelium growing from the inner stromal layer. Perithecia were initiated in the outer layer, just above the interface of the two layers. Natural onset of perithecial formation was associated with evidence of visitation by a prasitic fly (Phorbia phrenione). CONSIDERABLE ATTENTION has been focused recently on a group of clavicipitaceous fungi occurring endophytically in certain grass species of the subfamily Festucoidae (Latch, Christensen, and Samuels, 1984; White and Cole, 1985; White, 1987). These fungi have been implicated as the source of alkaloids which cause toxicosis in grazing cattle (Lyons, Plattner, and Bacon, 1986; White and Morgan-Jones, 1987). They have also been demonstrated to impart increased resistance to certain insect pests of grasses (Siegel, Latch, and Johnson, 1985; Clay, Hardy, and Hammond, 1985). Endophytic mycelium is present intercellularly in ground tissue of leaves and culms and is observable within carpels and caryopses. The endophytes are propagated vegetatively by growth of mycelium from the parental grass plant into the ovary, followed by penetration of the developing embryo within the caryopsis (Freeman, 1904; White and Cole, 1986). Endophytic mycelium of the ascomycete Epichloe typhina (Fr.) Tul. is widespread in certain grasses. Herbarium studies (White, 19 8 7) suggest that E. typhina is present in about half the individuals of Elymus canadensis L. in North America. The fungus is expressed externally (Fig. 1-10) as an ectophytic stroma, which is produced on the uppermost leaf sheath I Received for publication 24 October 1986; revision accepted 27 February 1987. The authors are grateful to Dr. Jerry Brand for use of materials and to the University of Texas for laboratory space at the Brackenridge Field laboratory where experiments were conducted. We also wish to acknowledge Drs. Philip M. Halisky and Gareth Morgan-Jones for their constructive reviews of the manuscript. 2 Current address: Dept. of Botany, Ohio State University, Columbus, OH 43210. (Fig. 1) of the culms of some of the endophytecontaining plants of E. canadensis (White, 1987). Occurrence of the stroma on the grass culm prevents emergence of the inflorescence and is commonly known as "choke disease" (Halisky, Saha, and Funk, 1985). Each spring a small percentage (1-10%) of the endophytecontaining plants of E. canadensis bear the ectophytic phase (Bultman and White, unpublished). In contrast, when Agrostis tenuis Sibth. and Dactylis glomerata L. are infected with E. typhina, a stroma always forms, resulting in the complete suppression of caryopsis formation by infected plants (Western and Cavet, 1959). In these grasses, spread of the endophyte appears to be limited to clonal growth of the host grass, with infection by ascospores an apparently rare event. Consequently, infected populations of these species are small and infrequently encountered (Bradshaw, 1959). While the endophyte reduces the fitness of infected individuals of A. tenuis and D. glomerata, it does not appear to substantially reduce fitness of infected individuals of E. canadensis. Similarly, the related endophytes of other grasses, such as Festuca arundinacea Schreb. and Lolium perenne L., have not been demonstrated to produce an ectophytic phase and thus apparently do not reduce fitness of those grasses (Latch et al., 1984; Siegel et al., 1985; White et al., 1987; White and Morgan-Jones, 1987). These exclusively vegetatively-reproducing forms have been referred to as nonchoke-inducing endophytes (Halisky et al., 1985). The close phylogenetic relationship of the nonchoke-inducing endophytes and the choke-inducing E. typhina has been inferred from the morphological similarities of the conidial states in vitro and on the common en-
96 citations
TL;DR: In this paper, a model of fungal growth in soil is described, where two biomass components, cell walls and cytoplasm, are considered, and the model predicts that equilibrium levels of active mycelium depend primarily on substrate input rate and yield efficiency and are independent of other parameters controlling substrate availability.
Abstract: A model of fungal growth in soil is described. Two biomass components, cell walls and cytoplasm are considered. Allocation of assimilates to cell wall and cytoplasm synthesis and the relative rate of cytoplasm translocation vary according to C and N availabilities. Model behaviour in relation to substrate supply is examined. For single substrate additions, active mycelium (cytoplasm-filled hyphae) shows a positive correlation to substrate availability, while total hyphal length (cytoplasm-filled + evacuated hyphae) shows an inverse response. For continuous substrate additions, the model predicts that equilibrium levels of active mycelium depend primarily on substrate input rate and yield efficiency and are independent of other parameters controlling substrate availability. Model assumptions about biosynthate allocation and cytoplasm translocation influence N mineralization and immobilization patterns. The model suggests that critical C:N ratios change during decomposition as the fungal biomass develops. The advantages conferred by the mycclial growth form, in terms of conserving energy and nutrient elements in resource-poor environments, are discussed.
94 citations
TL;DR: Cl Clover (Trifolium repens L.) plants were inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus clarum Nicol.
Abstract: Summary
Clover (Trifolium repens L.) plants were inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus clarum Nicol. & Schenck in three experiments performed in similar environmental conditions. Extra radical mycelium was separated from soil by the membrane filter technique and its total length was measured; viable amounts were assessed after staining with the fluorescent dye fluorescein diacetate (FDA). Total mycelium increased steadily, and reached its maximum length 8 weeks after inoculation, unlike viability rate which decreased, from an initial value of about 100% to less than 15% after a period of 5 to 8 weeks. Consequently, the length of viable mycelium decreased after the first weeks following inoculation. The viability of extra radical mycelium may be an important factor influencing nutrient uptake and translocation by the VAM fungus.
84 citations
TL;DR: Metarhizium album, a name widely regarded as a synonym of M. anisopliae, is restored for a fungus collected on plant- and leafhoppers (Homoptera : Auchenorrhyncha) from rice, and a synoptic key to the taxa is provided.
Abstract: Metarhizium album, a name widely regarded as a synonym of M. anisopliae, is restored for a fungus collected on plant- and leafhoppers (Homoptera : Auchenorrhyncha) from rice. In the Philippines and Indonesia it caused epizootics in populations of Nephotettix virescens and/or Cofana spectra, respectively. A single collection on an unidentified leaf hopper from mango is reported. Comparison of types revealed that M. brunneum is a synonym of M. album; the species is characterized by the pale brown colour of its conidial masses, clavate phialides (10–12.5 × 2–3.5μm), ovoid to ellipsoidal conidia ((3–4)4–6 × 1.5–2.5 μm) and growth of bulging masses of hyphal bodies rather than mycelium prior to sporulation. The primary taxonomic criteria for delimiting species of Metarhizium are the shapes of conidia and conidiogenous cells, presence or absence of a subhymenial zone of swollen hyphal bodies, and whether conidial chains adhere laterally to form prismatic columns. The occurrence of many natural and artificial colour variants of Metarhizium species suggests that colours of conidial masses and mycelium have only secondary taxonomic value. Conidial size is useful in delimiting varieties. A synoptic key to the taxa of Metarhizium is provided.
TL;DR: In this paper, the authors followed the decomposition of red clover root remains and described the process of decomposing the root remains, showing that organic matter mass loss was fast during the first 13 days (44%) and almost ceased after 30 days when about 29% of the organic material remained.
Abstract: We have followed the decomposition of red clover root remains and described the process. In this investigation, red clover roots, divided into three diameter classes: 4 mm, were incubated in mesh bags in a loam soil at a temperature of 22°C and a moisture of pF 2–3 for up to 196 days. Analyses were made on the initial dead plant material and on mesh-bag contents of the 1–4 mm roots for the amounts of water and ethanol solubles, solid polysaccharides, lignin, ash, carbon, nitrogen and fungal mycelium. Organic matter mass loss was fast during the first 13 days (44%) and almost ceased after 30 days when about 29% of the organic material remained. There was no notable difference in mass- or nitrogen loss from roots of different diameters. The carbon-to-nitrogen ratio of the root remains decreased from initially 25–27 to 11–13 at the end of the incubation. The high rate of mass loss at the beginning is explained by the considerable initial concentration of water-soluble substances (31%), being the fraction which decreased the fastest (roots 1–4 mm φ). Glucans comprising 40% of the initial root material, were degraded linearly to total mass loss. Other polysaccharides (galactans, mannans, xylans, arabans and rhamnans) disappeared more slowly than the glucans. The amount of total fungal mycelium within the decomposing root remains increased during the incubation from 55 to 867m g −1 of organic material.
TL;DR: Emergence of hyphae from the beads was influenced by the presence of sterile soil extracts prepared from a podzolic soil, an acid brown soil, a mesotrophic brown earth, an eutrophicbrown earth, and a rendzina, and Hyphae grew out of all the beads containing peat irrespective of the type of soil.
Abstract: Survival of Hebeloma crustuliniforme (Bulliard ex Fries) Quelet, grown in a liquid medium and subsequently entrapped in beads of calcium alginate, was tested under different conditions. Mycelium vi...
TL;DR: A number of mutant strains overproducing cellulase, β-glucosidase and xylanase enzyme were isolated from the cellulolytic fungus Penicillium pinophilum 87160iii after mutagenesis by u.v. irradiation and/or chemical treatment.
TL;DR: Biosynthesis of polygalacturonase (PG) by A. niger strain R 1/214 correlates with the morphology of mycelium in submerged culture and the mean specific PG‐synthesis increases with the degree of compactness ofMycelium.
Abstract: Biosynthesis of polygalacturonase (PG) by A. niger strain R 1/214 correlates with the morphology of mycelium in submerged culture. The mean specific PG-synthesis (PG-U · g−1 · h−1) increases with the degree of compactness of mycelium. PG-production can be optimized by a precise adjustment of the culture conditions after direct spore inoculation (diffuse mycelium) but the high synthesis as by compact mycelium is never obtained. Different reasons for the higher enzyme production by the pellet mycelium are discussed. PG-synthesis is assumed to be strictly connected with a limitation of nutrient and oxygen supply.
TL;DR: Uptake of phosphate by mycelium is reduced by increasing the concentration of phosphate in the growth medium from 10 μM to 10 mM, and the major portion absorbed by cords in the field remains within the segment exposed to radioactive solution, suggesting conversion of the phosphate to an immobile form unavailable for translocation.
Abstract: Phosphate uptake as a function of external medium concentration has been determined for mycelium grown in the laboratory, segments of cords collected from the field and cords in the field for a range of wood-decay basidiomycetes. Hofstee plots in all cases can be interpreted as indicating the presence of two uptake systems. Uptake of phosphate by mycelium is reduced by increasing the concentration of phosphate in the growth medium from 10 μM to 10 mM. The major portion absorbed by cords in the field remains within the segment exposed to radioactive solution, suggesting conversion of the phosphate to an immobile form unavailable for translocation.
TL;DR: The development of symptoms of brown rust (Puccinia hordei Otth.) of barley was examined in relation to the distribution of fungal mycelium within the leaf, the accumulation of chloroplastic starch and localized changes in the concentration of chlorophyll.
Abstract: Summary
The development of symptoms of brown rust (Puccinia hordei Otth.) of barley was examined in relation to the distribution of fungal mycelium within the leaf, the accumulation of chloroplastic starch and localized changes in the concentration of chlorophyll. Symptom development correlated exactly with the growth and distribution of mycelium within the leaf. Starch accumulated in cells associated with or directly surrounded by fungal mycelium, but rarely in cells beyond the leading edge of the colony. A photographic study of the development of a group of brown rust pustules from the flecking stage to the formation of green islands, using incident light and light transmitted through the leaf, suggested that the yellow colour of the flecks was not caused by chlorophyll breakdown, but that the major loss of chlorophyll occurred from regions between fungal pustules. This conclusion was supported by a study of the density of chlorophyll within different regions of the leaf (using the absorption of red light as a measure of chlorophyll density) and by extraction of chlorophyll from different regions of the leaf. These results are discussed in relation to the controversy surrounding the mode of formation of green islands.
TL;DR: Relationships between the hyphae of Agaricus bisporus (Lang) Sing and bacteria from the mushroom bed casing layer were examined with a scanning electron microscope, finding that attachment may be important in stimulation of pinhead initiation.
Abstract: Relationships between the hyphae of Agaricus bisporus (Lang) Sing and bacteria from the mushroom bed casing layer were examined with a scanning electron microscope. Hyphae growing in the casing layer differed morphologically from compost-grown hyphae. Whereas the compost contained thin single hyphae surrounded by calcium oxalate crystals, the casing layer contained mainly wide hyphae or mycelial strands without crystals. The bacterial population in the hyphal environment consisted of several types, some attached to the hyphae with filamentlike structures. This attachment may be important in stimulation of pinhead initiation.
TL;DR: Blended mycelial slurries of a variety of ectomycorrhizal fungi were assessed for their suitability as inoculum for containerized tree seedlings.
Abstract: Blended mycelial slurries of a variety of ectomycorrhizal fungi were assessed for their suitability as inoculum for containerized tree seedlings. Mycelium of most fungi tested, with the exceptions ...
TL;DR: Yeast cells of Candida albicans 1001 produced glucan-hydrolysing activity, most of which was due to an exo-1,3-beta-glucanase, but a significant (though lesser) reduction was also observed in yeast cells incubated in the same medium under conditions (temperature, cell concentration) that did not lead to formation of hyphae.
Abstract: SUMMARY: Yeast cells of Candida albicans 1001 produced glucan-hydrolysing activity, most of which was due to an exo-1,3-β-glucanase. The enzyme was periplasmically located; it could be found in culture medium samples, and was secreted by protoplasts when cultured under regeneration conditions. In contrast to most yeast exoglucanases, this enzyme was practically inactive against p-nitrophenyl-β-d-glucoside, hydrolysis of this substrate being carried out by a β-glucosidase located inside the cytoplasmic membrane and not secreted to the external medium. Supernatant fluids from cell-free extracts reached their maximum glucanase level after several days at 0°C, suggesting that the active enzyme was formed from an inactive precursor. Glucanase activity substantially decreased and sometimes disappeared from the cells when the yeast-to-mycelium transition was induced, but a significant (though lesser) reduction was also observed in yeast cells incubated in the same medium under conditions (temperature, cell concentration) that did not lead to formation of hyphae. It is suggested that C. albicans exo-1,3-β-glucanase may not be necessary for mycelial growth.
TL;DR: A non identified species ofPenicillium induced the formation of nodules on the root system of two species of alder (Alnus glutinosa and A.incana) that looked like young actinorhizae and showed no evident damage after the infection.
Abstract: A non identified species ofPenicillium induced the formation of nodules on the root system of two species of alder (Alnus glutinosa and A.incana). These so-called myconodules looked like young actinorhizae. Namely only some cortical cells of the young transformed root were invaded by the mycelium. Plasmalemma of the host-cell surrounded the hyphae when they penetrated in the cell, but then the fungus colonized all the cell, the contents of which degenerated. In spite of this necrophytic relationships the plant showed no evident damage after the infection.
Journal Article•
TL;DR: Skin reaction correlations were greatest within isolates, then for specific fungus parts, then between isolates and parts, and ELISA inhibition cross-reaction patterns among Epicoccum antigens were comparable to skin reactions while IgG patterns showed little variability.
Abstract: Comparable degrees of skin reactivity were observed towards spore and mycelium extracts from two isolates of Epicoccum and to one preparation of Alternaria in 35 rural and 120 university patients. The best experimental extracts detected Epicoccum sensitivity in 70% of the group tested while the commercial extract detected sensitivity in only 6%. Skin reaction correlations were greatest within isolates (eg, spore-A/mycelium-A), then for specific fungus parts (eg, spore-A/spore-B), then between isolates and parts (spore-A/mycelium-B). High correlations were found between individual IgG and IgE ELISA values for all antigens using serum from Epicoccum skin-reactive patients. ELISA inhibition results suggested that significant cross-reactivity exists between Epicoccum and Alternaria antigens recognized by IgG but not by IgE. ELISA inhibition cross-reaction patterns among Epicoccum antigens were comparable to skin reactions while IgG patterns showed little variability. Further characterization of spore/mycelium and interstrain recognition patterns among different immunoglobulin isotypes will be necessary before complete standardization of extracts from different parts of fungi will be possible. The use of spore material for skin testing and treatment of Epicoccum sensitivity appears to be both premature and unnecessary at this time.
TL;DR: Three isolates of Pisolithus tinctorius originating from different localities grew more poorly on selected carbon sources than did non-mycorrhizal fungi and the nutritional unavailability of cellulose, the photosynthate sucrose, fructose, pectin and pect in constituents for growth severely restricts the supply of utilizable carbon sources.
Abstract: Three isolates of Pisolithus tinctorius originating from different localities grew more poorly on selected carbon sources than did non-mycorrhizal fungi. The carbon utilization pattern did not change significantly with changes in composition on the basal medium or inoculum preparation, but did change with culture medium pH and addition of small amounts of glucose. An initial pH between 4 and 5 enhanced growth on disaccharides. Glucose supplementation allowed some growth on sucrose, fructose, and cellulose. Unexpectedly, respiratory activity was not necessarily accompanied by growth. Free [ 14 C]fructose was rapidly respired to CO 2 but was not used for growth. Respiration of fructose-and glucose-labelled sucrose demonstrated that glucose was readily oxidized to CO 2 while much less of the fructose was oxidized. Washed mycelium nevertheless assimilated free fructose for at least 7 h with some carbon appearing in ether and hot water extractables and in residual mycelium, as well as in two successive acid hydrolysates of residual mycelium. Endogenous respiration was inhibited by certain concentrations of glucose and total respiration was only slightly higher than endogenous respiration. Nutrition may play a role in restricting growth of P. tinctorius in roots to the ectomycorrhizal form. The nutritional unavailability of cellulose, the photosynthate sucrose, fructose, pectin and pectin constituents for growth severely restricts the supply of utilizable carbon sources. Respiration of sucrose and fructose without growth would scavenge out these potential sources of inducer glucose and thus prevent induction for growth on cellulose, sucrose, and fructose and would provide energy for maintenance of the mycelium. The rapid metabolism of cellobiose would similarly prevent accumulation of inducer glucose and provide energy for maintenance.
TL;DR: Transmission electron microscopy demonstrated that the mycelium in developing galls induced by smut fungi in the Tilletiaceae and Ustilaginaceae may be both intercellular and intracellular.
Abstract: Transmission electron microscopy demonstrated that the mycelium in developing galls induced by smut fungi in the Tilletiaceae (Tilletia caries on Triticum aestivum) and Ustilaginaceae (Ustilago nud...
TL;DR: Exposure to suboptimal growth temperatures for up to 8 days did not induce microcycle conidiation from inocula that did not form a slime spot at 28 degrees C, and enhanced mycelial growth preceded sporulation and overrode slime-spot formation on highly concentrated media.
Abstract: The effect of spore inoculum density, medium concentration, and temperature on slime-spot formation, spore yield, and mycelium production by Colletotrichum gloeosporioides on agar media were studied with a simple microplate assay. A steady-state spore yield (spore-carrying capacity) independent of inoculum density was reached only on media that supported good fungal growth and sporulation. The spore-carrying capacity was reached earlier, the denser the inoculum. On standard mycological media a high inoculum density (2.5 x 10 spores per ml) resulted in a slimy mass of conidia forming a slime spot, a phenomenon associated with greatly reduced mycelium formation and indicative of microcycle conidiation. In contrast, for a similar inoculum density, enhanced mycelial growth preceded sporulation and overrode slime-spot formation on highly concentrated media; a very low medium concentration resulted in much less mycelium, but spore production was also decreased. Exposure to suboptimal growth temperatures of 36 to 48 degrees C for up to 8 days did not induce microcycle conidiation from inocula that did not form a slime spot at 28 degrees C.
TL;DR: A red pigment which is induced in sugarcane stalks ( Saccharum officinarum L.) upon infection with Colletotrichum falcatum was assayed for its effect on spore germination and radial mycelial growth as mentioned in this paper.
TL;DR: Zygorrhynchus moelleri antagonized some soil-borne fungi on agar and in composts, and produced substances inhibitory to growth of colonies of test fungi on Agar.
Abstract: Zygorrhynchus moelleri antagonized some soil-borne fungi on agar and in composts. Filtrates of Z. moelleri cultures contained high levels of β-1,3-glucanase (exoglucanase) and β-1,3(4)-glucanase (endoglucanase) when the fungus was grown on hyphal wall material from Rhizoctonia solani or Pythium intermedium as sole carbon source. Lower exo- and endoglucanase activities were produced on Fusarium oxysporum f. sp. lini (F.o.l.) hyphal walls while insignificant levels were produced on Z. moelleri hyphal walls. Protease was also produced when Z. moelleri was grown on hyphal wall material, but chitinase or cellulase were not detected. Optimum production of both glucanases occurred in media at pH,6 to 7 and activity was optimal at pH 5. The enzymes were active over a temperature range in excess of 20–50 °C but optimum activity occurred at 40 °C.
Cell free culture filtrates containing exo- and endoglucanase activity lysed living hyphal walls of R. solani, P. intermedium, Verticillium albo-atrum and F.o.l. although walls of the latter were least sensitive to lytic activity. The culture filtrates did not lyse living mycelium of Z. moelleri. Z. moelleri also produced substances inhibitory to growth of colonies of test fungi on agar.
In glasshouse experiments disease severity in flax induced by R. solani and P. intermedium, in parsley by P. paroecandrum and in radish and Zinnia by P. intermedium was suppressed in composts inoculated with sporangiospore suspensions of Z. moelleri.
TL;DR: The timing and nature of these changes suggest that gradients in nutrient concentration are not responsible for mycelial differentiation and favour diffusion to the margin of paramorphogenetic staling compounds formed at the colony centre when growth ceases.
Abstract: The development of the vegetative mycelium of Neurospora crassa was observed from spore germination to formation of a differentiated mycelium at the margin of a mature colony. During the first 22 h of growth there was little variation in extension rates and diameters of all hyphae, and the angle subtended by branch hyphae was 90°. Between 22 h and 28 h branch angle decreased to 63° and then remained constant. Extension rates and diameters of leading hyphae increased in parallel after 22 h, reaching maxima at 44 and 40 h respectively, and a hierarchy developed such that branch hyphae were narrower and extended more slowly than parent hyphae from which they arose. The timing and nature of these changes suggest that gradients in nutrient concentration are not responsible for mycelial differentiation and favour diffusion to the margin of paramorphogenetic staling compounds formed at the colony centre when growth ceases.
TL;DR: The P. ostreatus mycelium grown in the peat extract-based medium was characterized by a high protein content, a favorable amino acid composition and high concentrations of essential fatty acids and minerals that permit its consideration as a potential food.
TL;DR: While S. albus G took up oleandomycin, S. antibioticus showed a decreased permeability to the antibiotic, suggesting a role for cell permeability in self-resistance.
Abstract: SUMMARY: Resistance to oleandomycin in Streptomyces antibioticus, the producer organism, was studied. The organism was highly resistant in vivo to the antibiotic but sensitive to other macrolides and lincosamides. Protein synthesis in vivo by mycelium of S. antibioticus was more resistant to oleandomycin than that by mycelium of Streptomyces albus G, an oleandomycin-sensitive strain, and this resistance was dependent on the age of the culture, older mycelium of S. antibioticus being more resistant to oleandomycin than young mycelium. [3H]Oleandomycin was capable of binding to the same extent to the 50S subunits of the ribosomes of both organisms. Oleandomycin also inhibited in vitro protein synthesis by ribosomes obtained from an oleandomycin-production medium at the time when maximum levels of oleandomycin were being produced. A clear difference between the ability of the two organisms to incorporate exogenous oleandomycin was observed. Thus, while S. albus G took up oleandomycin, S. antibioticus showed a decreased permeability to the antibiotic, suggesting a role for cell permeability in self-resistance.