Mycelial Production Research Articles

Pectic enzyme activity of spruce (S) and pine (P) strains of Heterobasidion annosum (Fr.) Bref

Growth and pectic enzyme activity were compared between S and P intersterility groups of Heterobasidion annosum (Fr.) Bref. occurring in Europe. In living, infected root sapwood of Norway spruce ( Picea abies) (L.) Karst, the growth of P strains was significantly slower than that of S strains. The pectic activity of the P strains was greater than that of the S strains both in relation to mycelial production and to the protein content of the culture filtrate. Thin-layer chromatography of samples from cultures and reaction mixtures revealed qualitative and quantitative differences in substrate cleavage patterns between the two intersterility groups. Whereas S strains mainly produced exopolygalacturonase, P strains produced endopolygalacturonase. The P strains showed a high polygalacturonase activity both at pH 5 and pH 8. This intersterility group was also characterized by strong pectin lyase activity, particularly at pH 8. In infected root sapwood of spruce the P strains released more soluble polymers and oligomers from pectin than did the S strains. Thin-layer chromatography of reaction products showed that the cleavage patterns in vivo and in vitro were similar.

Changes in pH and the Production of Organic Acids During Colonization of Tomato Petioles by Botrytis cinerea

AbstractAfter inoculation of petiole stumps of tomato plants with a tomato isolate of B. cinerea, a transition zone between water‐soaked and apparently healthy tissue became clearly visible. Hyphal colonization occurred up to approximately 2 mm beyond this zone. In the colonized tissue the pH values were lower than in the healthy tissue. In the region with most of the tips of the advancing hyphae, however, pH values were slightly, but consistently, higher. In the colonized tissue concentrations of oxalic, citric and succinic acid were higher than in the tissue of healthy, non‐inoculated petioles. In vitro this isolate of B. cinerea produced citric, malic and succinic acid. Oxalic acid, however, could not be detected. In media enriched, with citric or malic acid, mycelial production was higher than in media without this enrichment.

Interactive Effects of Inoculum Density, Agitation, and Ph On Dimorphism In A Salt Marsh Isolate ofAureobasidium Pullulans

When a salt marsh isolate ofA. pullulans was grown under all combinations of three different hydrogen ion concentrations, two levels of inoculum density, and three agitation rates, both first- and secondorder interactions occurred which affected the percentage of mycelial development as well as mycelial and yeast cell biomass production. Although these interactions indicate that the effect of a single environmental factor on development depends on the level of the other interacting factors, certain trends associated with individual factors were evident. Low agitation favored mycelial development both on a percentage and a dry weight basis while high agitation favored production of yeast cells. High inoculum density tended to promote production of mycelium, whereas a pH of 7.5 inhibited yeast cells.

Interactive Effects of Inoculum Density, Agitation, and pH on Dimorphism in a Salt Marsh Isolate of Aureobasidium pullulans

When a salt marsh isolate of A. pullulans was grown under all combinations of three different hydrogen ion concentrations, two levels of inoculum density, and three agitation rates, both first- and second-order interactions occurred which affected the percentage of mycelial development as well as mycelial and yeast cell biomass production. Although these interactions indicate that the effect of a single environmental factor on development depends on the level of the other interacting factors, certain trends associated with individual factors were evident. Low agitation favored mycelial development both on a percentage and a dry weight basis while high agitation favored production of yeast cells. High inoculum density tended to promote production of mycelium, whereas a pH of 7.5 inhibited yeast cells.

Toxigenic fungi and the deterioration of Nigerian poultry feeds.

Growth of toxigenic strains of Aspergillus clavatus Des. and Aspergillus flavus Link at 30 degrees C on milled poultry feeds led to a considerable decrease in the protein, oil and crude fibre contents of the feed substrate. A corresponding increase in the free fatty acid fractions of the feeds due to the activities of these microbes was also recorded. Rapid degradation of the feedstuff by both species was recorded at a temperature of 25 degrees C and 30 degrees C and a pH range of 4.8-6.4. When grown on feed infusion broth at 30 degrees C, the highest amounts of mycelial production with sporulation of both fungal species occurred within the 8-day incubation period. A determination of their extra-cellular enzyme profile showed the production of amylases, pectate lyase, cellulases, proteases, lipases, xyalanases, DNase and RNase. All the carbon and nitrogen sources used (except L-sorbose and DL-tryptophan), supported good mycelial growth with sporulation. An optimal C:N ratio of 5.0:4.5 and 7.5:3.0 was recorded for growth and sporulation of A. clavatus. For A. flavus, a C:N ratio of 7.5:4.5 was found best for growth and 5.0:3.0 for sporulation.

Microcycle Conidiation and Spore-Carrying Capacity of Colletotrichum gloeosporioides on Solid Media

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.

Production of patulin and griseofulvin by a strain of Penicillium griseofulvum in three different media.

Production of patulin and griseofulvin by a strain of Penicillium griseofulvum is described. Mycelial dry weight, pH and production of patulin and griseofulvin were assayed in a minimal and a complete medium; patulin or griseofulvin production was assayed in apple juice.

Microplate Assay for Colletotrichum Spore Production

A simple microplate method was devised to assay spore production by Colletotrichum gloeosporioides by growing the fungus on 1 ml of solid media in the wells of tissue culture plates. Growth and sporulation on microplates were compared at days 4 and 8 with growth and sporulation in 100-ml liquid batch cultures that involved 11 common media. Spore production per unit volume of medium was the same for solid and liquid forms of the media. Qualitative assessment of mycelial growth measured on microplates agreed with that of growth measured in liquid cultures. The microplate assay indicated that V8 juice was the best medium and that an organic content of about 6 mg/ml was optimal for high sporulation and low mycelium production. The assay provides a convenient, rapid, and inexpensive means of screening media for the production of fungal conidia in large numbers, to be used, for example, in biological control programs.

Glucoamylase production and activity by Aspergillus clavatus Des., a toxigenic fungus from malting barley

The ability of a toxin producing strain of Aspergillus clavatus (HWU-GD1) from malting barley to hydrolyse starch at 30° C was demonstrated. Peak glucoamylase production was recorded on day 4 within the 5-day incubation period with a good correlation established between mycelial growth and enzyme production. A rapid disappearance of the starch in the growth-medium was accompanied with an accumulation of glucose in the medium within the first 48 h of incubation and a rapid drop in pH from a high level of 6.9 to as low as 4.2. Growth on varying carbon sources showed that glucoamylase production by A. clavatus strain HWU-GD1 did not depend on the presence of starch in the growth medium although its inclusion in the medium enhanced glucoamylase production. The enzyme was most active at pH 5.2 and a temperature of 40° C.

Spontaneous mutability and colony morphology of Gibberella baccata

Cultural instability is a common phenomenon in the genus Fusarium. As with other species, Gibberella baccata (Fusarium lateritium) contains cultures that are less morphologically stable than others. When grown on certain media, such as potato dextrose agar, these cultures produce areas of aberrant growth (mutant patches) after 6 weeks. Single conidial cultures from these patches produce colonies different from the original culture and from each other in growth rate, colony color, aerial mycelium production, and pionnote production. Random ascospore analyses of crosses of the original morphological type to the mutant types showed there had been a one gene change in each case. Mutant patch forming and nonforming isolates of Gibberella baccata were crossed in all possible combinations, and the progeny were rated for ability to produce mutant patches. Broad sense heritability estimates for inheritance of mutant patch formation were high (60.0 to 95.9%), strongly indicating a genetic basis with a limited number of genes involved. The mutator activity of these genes appeared to be conditional and mutant patch development was dependent on the presence of some unknown factor in certain media rich in carbohydrates and other compounds.Key words: Gibberella baccata, Fusarium lateritium, colony morphology, spontaneous mutability, cultural instability.

Mycelial interactions in Daldinia concentrica

Genetically different isolates of Daldinia concentrica always produced demarcation zones when paired against one another. The morphology of these zones varied with respect to the width and shape of regions of white aerial mycelium ( wam ). In pairings between single ascospore isolates from the same perithecium, evidence was obtained for a multigenic recognition system. The wam usually widened, either symmetrically or asymmetrically, resulting in ‘bow-tie’ and ‘hour-glass’ shaped interaction zones. Bow-tie shaped zones were associated with inhibition of the parent colony margins and emergence of a fan-shaped wam . Pairings between isolates from different stromata and from different wood samples generally resulted in a narrower wam of more constant width at the interaction interface. However, a large number of unilateral ‘pincer-like’ interactions occurred in which one isolate gained territorial dominance over the other. These interactions followed outgrowth of a wam from the interaction interface associated with inhibition of extension of the suppressed isolate. Evidence that the wam contained temporarily heterokaryotic mycelium was obtained by subculturing single hyphal tips. These observations imply the existence of mycelial recognition systems which are fundamentally similar to those governing mating in heterothallic Basidiomycotina, but which do not enable production of a stable secondary mycelium.

Effects of micro-elements on production of Roridin E by Myrothecium roridum, a strain pathogenic to muskmelon ( Cucumis melo)

Trace elements added to a synthetic culture medium influenced the level of Roridin E and mycelium production by a strain of Myrothecium roridum pathogenic to muskmelons. Zinc added at 5 μg ml−1 increased Roridin E production 35-fold. Iron and copper produced similar effects on the production of Roridin E, i.e. increasing levels of iron and copper increased the production of Roridin E. High levels of molybdenum were inhibitory for the production of Roridin E. At all levels of added manganese, the growth of the fungus was not affected significantly.

The Ecology and Physiology of the Fungal Mycelium.

Contributors Preface Nomenclature 1. The fungal mycelium - and historical perspective P. H. Gregory 2. Regulation of hyphal branching and hyphal orientation A. P. J. Trinci 3. Colony ontogeny in basidiomycetes G. M. Butler 4. Hyphal interactions in Schizophyllum commune: the di-mon mating T. T. Nguyen and D. J. Niderpruem 5. Hyphal fusion in Coriolus versicolor R. C. Aylmore and N. K. Todd 6. The mycelial habit and secondary metabolite production M. O. Moss 7. Water flow through mycelia D. H. Jennings 8. Morphogenesis of the Serpula lacrimans colony in relation to its functions in nature S. C. Watkinson 9. Distribution, development and functioning of mycelial cord systems of decomposer basidiomycetes of the deciduous woodland floor W. Thompson 10. The structure and function of the vegetative mycelium of mycorrhizal roots D. J. Read 11. Autecology and the mycelium of a woodland litter decomposer J. C. Frankland 12. The micro-environment of basidiomycete mycelia in temperate deciduous woodlands L. Boddy 13. Interrelationships between vegetative development and basidiocarp initiation M. Raudaskoski and M. Salonen 14. Physiology and ecology of rhythmic growth and sporulation in fungi G. Lysek 15. Senescence in Podospora anerina and its implication for genetic engineering K. Esser, U. Kuck, U. Stahl and P. Tudzynski 16. The mycelial biology of Endothia parasitics. I. nuclear and cytoplasmic genes that determine morphology and virulence S. L. Anagnostakis 17. Variation and heterokaryosis in Rhizoctonia solani N. A. Anderson 18. Interspecific mycelial interactions - an overview A. D. M. Rayner and J. F. Webber 19. Mycelial development and lectin-carbohydrate interactions in nematode-trapping fungi B. Nordbring-Hertz 20. Mycelial interactions and mitochondrial inheritance in Aspergillus J. H. Croft and R. B. G. Dales 21. Inter-mycelial recognition systems in Ceratocystis ulmi: their pysiological properties and ecological importance C. M. Brasier 22. The mycelial biology of Endothia parasitica. II. vegetative incompatibility S. L. Anagnostakis 23. The biological consequences of individualistic mycelium A. D. M. Rayner, D. Coates, A. M. Ainsworth, T. J. H. Adams, E. N. D. Williams and N. K. Todd Index of generic and specific names Subject index.

Effects of the biodeterioration caused by two molds on some food substances ofAnanas comosus

The effect of spoilage produced byCeratocystis paradoxa andCurvularia verruculosa on the sugar, protein and citric acid contents of host pineapple fruits was investigated. The spoilage byC. verruculosa produced complete loss of sugars in fruits. InC. verruculosa- andC. paradoxa-diseased fruits, complete loss of citric acid was recorded, accompanied by an increase in the total protein content of the fruits. The total acidity of infected fruits was found to vary between pH 4.0 and 6.0, while that of control fruits was between pH 6.2 and 6.5.Ceratocystis paradoxa andC. verruculosa had optimum mycelial production atpH 6.0 and 7.0, respectively.

Production of Mushroom Mycelium in Supplemented Acid-Extract from Peat

Nutrient-supplemented peat extract was employed as a substrate for submerged cultivation of the edible mushroom Agaricus cam-pestris mycelium in a stirred fermentor. Yeast extract and several inorganic sources of nitrogen, individually and in various combinations, were used as supplements. The addition of nutrients, in most cases, produced 10% to 60% higher mycelial concentration and in all cases practically doubled the nitrogen content of the mycelium, as compared to the non-supplemented media. Nitrogen and phosphorus supplements were found to be necessary to enhance the mycelial growth; however, there was no need for additional potassium. Yeast extract in a concentration of 0.5% was the best supplement, producing 7.1 g/L dry mycelium in 9 days. The yield and efficiency were 49% and 24% respectively. The mycelium contained 45% crude protein (N × 6.25) and an amino acid composition comparable to the FAO standards.

Invasion of wood by basidiomycetous fungi II. Obliterated differences between pathosism and saprophytism on pre‐degraded wood substrates in monoxenic culture

AbstractMycelial production and linear extension growth of 41 wood‐destroying basidiomycetous fungi (WBF) whose pathogenicity and kratovirulence levels permitted their subdivision into 7 fungal categories was determined on nonsterile and autoclaved wood dust materials from fresh, discoloured (nondecay), and decay wood samples. The resident microflora of nonsterile wood meals compels the intruding WBF mycelium to mobilize its entire competitive ability when going to colonize a contaminated substrate. This demand excludes the pathogenic WBF from utilizing the non‐sterile substrates but allows for extensive development of the fresh‐wood and successive saprophytes that afford the required kratovirulence level. On sterilized wood dust, any differences in the growth patterns of pathogenic and saprophytic WBF vanish immediately. Sterile fresh wood samples from host and nonhost trees the latter being never infected in the field allow for widely uniform mycelial production by fungal species with wide or extremely narrow host range. Some fungi display, in addition, a strong substrate preference to certain natural host tree species or their close relatives. No correlation was found between the total exoenzymatic activity reported for the fungus concerned and its mycelial production. Top values of mycelial formation were observed in fungi with lowest enzymatic activity as well as in producers of normal enzyme quantities while some brown‐rot fungi showed extremely restricted mycelial output although they are known for enzymatic activities to be highest.Among the 41 fungal species listed, 25 prefer certain particular nondecay and decay wood samples to fresh wood meal although the general rule is a higher mycelial production on fresh wood. The addiction to pre‐degraded wood can be traced, surprisingly, throughout all fungal categories with the tendency to abate in saprophytic ones. The brown‐rot fungi are more frequently stimulated by the discoloured nondecay wood while white‐rot fungi tend to prefer decay wood samples. The partially diminutive mycelial production in certain brown‐rot fungi means no defect in vitality or wood‐decay capacity. The weekly linear extension growth figure LE7 of the fungal mycelia can reach top values throughout the 7 fungal categories. No relationship was detected between rapid mycelial growth and both kratovirulence level or pathogenic potency. Fungi most reliably transplanted to raw substrates have medium‐sized LE7 figures. It is concluded that the striking differences between pathogenic and saprophytic members of WBF they display in their competitive ability immediately vanish in the absence of substrate microorganisms. The in vitro tests neither reveal differences in a striking host substrate specificity, the preference to fresh or decay wood, mycelial dry matter production, general enzymatic particularities, and weekly mycelial growth rate.

Effects of captan on the growth and cellulase production of Aspergillus aculeatus and Botryodiplodia theobromae

AbstractThe effects of captan on the production of mycelia and cellulolytic enzymes of Aspergillus aculeatus and Botryodiplodia theobromae were investigated in culture. There was decrease in mycelia of both fungi with increase in captan concentration in ppm. No fungal growth was recorded at 400 ppm. Captan at 10–50 ppm at 25 and 30 °C induced both fungi to produce more mycelia than in control cultures. The effect of captan concentration on the production of cellulases showed a decrease in quantity with increase in concentration. At 400 ppm no cellulase was produced by both fungi. There was a general decrease in cellulase production with increase in temperature either in control or experimental cultures. In cultures incorporated with captan, the cellulolytic activities of A. aculeatus (at 10 ppm) and B. theobromae (at 10 ppm, 50 ppm) were found to be relatively high.

The growth characteristics of Saccharomycopsis lipolytica: morphology and induction of mycelium formation

When Saccharomycopsis lipolytica was grown on minimal medium supplemented with glucose or n-hexadecane, all the cells of the culture remained in the yeast form. In complex medium, a mixed morphology of yeast and mycelial forms appeared. If the cells were grown on minimal medium supplemented with N-acetylglucosamine as the carbon source, a reproducible system for the production of mycelium was obtained. Neither temperature, pH, nor several other carbon sources were able to induce a reproducible yeast–mycelial transition. Mycelium formation is maximal after 12–15 h of incubation (in the presence of N-acetylglucosamine) and decreases with longer incubating times when N-acetylglucosamine is exhausted. During mycelium formation a considerable increase took place in dry weight; the cell numbers, however, remained almost constant between 12–15 h. Electron microscopy shows mycelium with a smooth surface, a great amount of mitochondria and a low degree of branching.

The effect of free-living nematodes and compost moisture on growth and yield in Agaricus brunnescens

The responses of four mushroom cultivars ('PSU-310,' 'PSU-324,' 'PSU-348,' and 'PSU-344') exposed to free-living nematode infestations were compared in two experiments by quantitatively determining the amount of mycelium in compost samples using a laccase assay technique. The amount of mycelial production for cultivars 'PSU-310,' 'PSU-324,' and 'PSU-348' in the control treatments of both studies was similar. While cultivar 'PSU-344' produced less mycelium as shown by laccase production, mycelial production was greatly reduced for all four cultivars exposed to nematode infestations in a high-moisture compost (78%) over the duration of the experiment. The initial compost moisture is implicated as a critical factor influencing the potential damage caused by nematode infestations.

Effect of pyridazinone herbicides on growth and aflatoxin release by Aspergillus flavus and Aspergillus parasiticus.

The influence of pyridazinone herbicides on aflatoxin production by Aspergillus flavus and A. parasiticus was studied in liquid media. Mycelia production was not affected by 20, 40, or 60 micrograms of herbicide per ml; however, aflatoxin production by A. parasiticus was higher in media with herbicide, whereas A. flavus produced lower aflatoxin levels.