Mycelial Production Research Articles

Entomophthora coronata, the Etiologic Agent of a Phycomycosis of Horses

(1961). Entomophthora Coronata, the Etiologic Agent of a Phycomycosis of Horses. Mycologia: Vol. 53, No. 3, pp. 307-312.

Developments in the production of mushroom mycelium in submerged liquid culture

AbstractThe process for the production of mushroom mycelium for food purposes has great potentiality. It would offer a simple, mechanized, inexpensive method for producing a nutritious food. Mushroom mycelium can be cultivated in submerged liquid culture on simple carbohydrate and nitrogen compounds with mineral salts. Yields are high and no special production problems are involved. Those species reported to have flavour are Agaricus campestris, Morchella crassipes, Lepiota rachodes, and Coprinus comatus. The mycelial growth is usually either in ball form or dispersed. The dispersed form, characterized by fine mycelium and secondary spores, may be a physiological mutation which gives greater yield but less flavour. Mycelium grown on solid media is said to have greater flavour than mycelium grown in submerged culture. Several methods for enhancing the flavour of the mycelium have been investigated. The taste of the mycelium has been variously reported from flavourless to equivalent or even preferable to that of the fruiting bodies. The fact remains, however, that it is only the problem of taste that has kept the process from commercial exploitation.

Cytological Investigations of Kabatiella caulivora

Cole, Herbert, Jr., and Houston B. Couch. (Penn. State U., University Park.) Cytological investigations of Kabatiella caulivora. Amer. Jour. Bot. 46(1) : 12-16. Illus. 1959.—Initial growth of K. caulivora on artificial media is characterized by budding, yeast-like, conidia, exclusive of mycelia. After 14 days growth, at 20°C., mycelial growth becomes macroscopically evident. A study of the germination behavior of a total of 5500 conidia from the initial yeast-like growth stage showed 59 to germinate by the production of mycelia, while the balance germinated by budding. Five thousand conidia of the mycelial growth type were studied in a successive, single-spore transfer series, and, in all cases, conidial germination continued to be by means of germ tubes. Conidia of both growth forms were studied by means of bright field and phase contrast microscopy, and found to be multinucleate—possessing variable nuclear numbers, ranging from 1-8 per cell. Mean nuclear number for both the mycelial and conidial types was 2.8. All nuclei of both growth types appeared to contain the same chromosome complement. The cultural variability exhibited by K. caulivora cannot be reconciled with the concept of dual phenomenon. It is suggested, rather, that the mycelial homotype probably arises as the result of a unidirectional mutation within the conidial growth form.

A microchemical method for detecting antifungal substances

A microchemical method for detecting inhibitors of fungal grwoth has been devised. The procedure involves the determination of mycelium production by use of acidified potassium dichromate. The method is rapid, reproducible and is sensitive to the antifungal antibiotic, actidione, in concentrations of less than 0.10 μg./ml. when Fusarium oxysporum f. cubense is used as the test organism.

A Method of Obtaining Pure Radioactive b-Carotene Using Phycomyces blakesleeanus

SUMMARYA reliable method for producing and purifying radioactive β-carotene by an isolate of Phycomyces blakesleeanus in still culture is described in detail. Only a trace of carotene was produced during the early phase of rapid mycelial growth. Carotenogenesis became appreciable as the phase of rapid growth declined, and continued for 4 to 5 days after the production of mycelium nearly ceased. Conditions highly favorable for growth or sporulation were unfavorable for the production of β-carotene. The carotene content of the mycelium reached 0.3 to 0.35 percent after 8 to 9 days of incubation. A 4- to 7-day-old culture grown on 25 ml of medium utilized as much as 12.2 mg of potassium acetate daily. Less glucose was utilized by cultures receiving added acetate than was utilized by the controls. When labeled acetate was added on the fifth day, radioactive β-carotene was synthesized. About one C14 atom out of 240 supplied as labeled acetate was recovered in crystalline β-carotene.

A Method of Obtaining Pure Radioactive β-Carotene Using Phycomyces Blakesleeanus

SUMMARYA reliable method for producing and purifying radioactive β-carotene by an isolate of Phycomyces blakesleeanus in still culture is described in detail. Only a trace of carotene was produced during the early phase of rapid mycelial growth. Carotenogenesis became appreciable as the phase of rapid growth declined, and continued for 4 to 5 days after the production of mycelium nearly ceased. Conditions highly favorable for growth or sporulation were unfavorable for the production of β-carotene. The carotene content of the mycelium reached 0.3 to 0.35 percent after 8 to 9 days of incubation. A 4- to 7-day-old culture grown on 25 ml of medium utilized as much as 12.2 mg of potassium acetate daily. Less glucose was utilized by cultures receiving added acetate than was utilized by the controls. When labeled acetate was added on the fifth day, radioactive β-carotene was synthesized. About one C14 atom out of 240 supplied as labeled acetate was recovered in crystalline β-carotene.

Production of mushroom mycelium by submerged cultivation

AbstractYields and flavour of mycelium of edible fungi grown in stirred, aerated culture have been investigated. Satisfactory harvests can be obtained, but flavour, when present, is only weak. Methods for the enhancement of flavour after the harvesting of the mycelium have been tried but have been unsuccessful.

Factors affecting the germination of sclerotia and mycelial growth of Sclerotium rolfsii Sacc.

The effect of cultural conditions on mycelial growth and production of sclerotia by two isolates of Sclerotium rolfsii is described. The two isolates differed chiefly in numbers and weights of sclerotia produced, and in their ability to utilize lactose and nitrate nitrogen. The isolates grew well on a variety of media and utilized a wide range of carbon and nitrogen compounds. On agar media, linear growth was most rapid at 30° C.; in liquid media best growth, as assessed by weight of mycelium, occurred between 20° and 30° C.; different optimal temperatures were obtained when cultures were harvested periodically over 24 days. For one isolate the optimum temperature for production of sclerotia was 10° C. The optimum pH for growth was near 3·0. Both isolates rapidly reduced the pH of media suitable for good growth to values between 2·5 and 4·0. Sclerotia germinated well in thin films of distilled water. The effects of temperature, pH, humidity, soil extracts and nutrient solutions on germination are described. Germination was considerably reduced on or in soil, or when sclerotia were submerged in water, but when the soil or water was aerated, almost all sclerotia germinated.

ペニシリン醗酵に関する研究

The degree of varying the lactose-glucose ratio on penicillin yield was studied in submerged cultures. In shake flask culture, the yield of penicillin in corn steep liquor media was smaller when glucose was used as a main source of carbohydrate. Inferiority of glucose to lactose was due to the metabolic unbalance between carbohydrate and nitrogen-containing compounds resulting from its too rapid utilization, leading to an early setting in of mycelial autolysis. The superiority of lactose was associated with its slow rate of utilization as compared with glucose. However, at high agitation and aeration rate in 5l-jar culture, the use of high glucose concentration was advantageous with rapid, high penicillin yields when pH was adjusted at 7, 2 with sulfuric acid during the fermentation. Active penicillin synthesis was performed during the sugar starving period just after the rapid production of mycelium. This marked difference in yields between these two types of fermentations seemed to be attributed in part to the agitation and aeration.

The Occurrence of Arachniotus Citrinus in Soils

Arachniotus citrinus was first described by Massee and Salmon in 1902 (3). This member of the family Gymnoascaceae was observed growing on kangaroo dung collected in the London Zoo. Morphological studies were made on the gross specimen only, as cultivation of the fungus on synthetic media was not attempted. Since that date no fur? ther observations of this ascomycete have been reported. Recently, while a large number of Tennessee soil samples were being screened for the presence of Histoplasma capsulatum and Microsporum gypseum, two soil samples yielded A. citrinus. One isolate was recov? ered indirectly from soil by passage through mice (2), while the second was observed developing adventitiously on strands of sterilized human hair used as bait for isolation of M. gypseum (1). A. citrinus grew readily on Sabouraud dextrose agar, forming a white cottony colony which slowly turned lemon-yellow 3 in color as asci and ascospores were developed. On Czapek's agar mycelial development was sparse but numerous lemon-yellow clusters of asci were formed. There was scant production of mycelium on sterilized rabbit dung pellets and rabbit dung extract agar (Fig. 1A). However, this medium was excellent for inducing ascus formation. Microscopic examination of the fungus grown on all these media revealed essentially similar findings. It was noted that copulation branches arose from mycelial filaments and coiled about each other (Fig. 1B). From these copulation branches asci were successively developed (Fig. 1C). This successive development of asci from the copulation branches led to the formation of clusters of asci along the hyphae (Fig. ID). No signs of a peridium were found. Each ascus enclosed eight elliptical, smooth, lemon-yellow spores (Fig. ID). When mounted in

STUDIES ON THE PHYSIOLOGY OF ELSINOE VENETA

A study was made of the effect of certain nutritional and environmental factors on the growth and pigmentation of the mycelium, the sporulation, and the germination of the conidia of a "convoluted" isolate of Elsinoe veneta (Burkh.) Jenkins, the fungus responsible for the anthracnose disease of raspberries. This isolate utilized with varying degrees of efficiency various mono-, oligo-, and polysaccharides as well as certain organic alcohols as its sole source of carbon for growth. Either a nitrate, ammonium, amino, or imidazole nitrogen compound supported the fungus in culture. Maximum growth of the mycelium occurred in the presence of soluble starch and asparagine, whereas optimum sporulation of the conidia was obtained on media containing potato starch and sodium nitrate. In general, the production of conidia was markedly reduced on media favorable for excessive vegetative growth. Both a decrease in the volume of the medium and in the concentration of either a specific nutrient or of total nutrients adversely influenced the production of mycelium. Temperatures above 30 °C. and below 21 °C. decreased the percentage germination of conidia and restricted the growth of the fungus. Growth and sporulation occurred over a wide range of pH values. The optimum initial pH for both growth and sporulation was 4.0. E. veneta produced conidia and grew as well in continuous darkness as in alternate diffuse light and darkness. Young potted raspberry plants growing in the greenhouse, when inoculated with conidia produced in culture, developed typical anthracnose lesions on the canes.

The reproductive pattern of Micromonospora vulgaris.

SUMMARY: The thermophilic actinomycete Micromonospora vulgaris resembles known mesophilic members of the genus Micromonospora in reproducing by means of small retractile spores borne singly on lateral branches of the vegetative mycelium. Its distinctive feature is the consistent production of a secondary aerial mycelium under optimal laboratory cultural conditions and in grass composts during the high temperature phase. This aerial mycelium is composed of abundantly branched, hydrophobic filaments which rapidly segment. The cells in these filaments may in turn give rise to similar refractile spherical spores borne singly on very short lateral branches. The reproductive pattern here described is one of the most complex yet known among the actinomycetes. It is thought that the aerial phase of development is intimately associated with the thermophilic nature of the organism.

The Culture of Claviceps purpurea. I. Growth and Nutrition in Submerged Culture

Claviceps purpurea was found to be capable of prolific mycelial development in submerged culture. Of the numerous carbon and nitrogen sources investigated, it was found that mannitol (2 per cent) and casein hydrolysate (1 per cent) incorporated in a basic nutrient solution allowed maximum production of mycelium. An average yield of 1.48 Gm. of dry weight of growth per 100 ml. of medium in a period of seven days following minimum inoculation was obtained. A correlation between growth and change in the hydrogen ion concentration of the culture medium was observed. It appears possible to predict the optimal fermentation time in any medium by a determination of pH. Strain variation of the organism has been emphasized as an important factor in the submerged culture of C. purpurea.

Temperature/growth relationships of a thermophilic actinomycete, Micromonospora vulgaris.

SUMMARY: The only thermophilic actinomycetes found in composts made from lawn cuttings were members of the genus Micromonospora. The isolates obtained agreed in the main with the description of M. vulgaris (Tsiklinsky) Waksman, Umbreit & Cordon. Three strains have been studied in detail. They are true thermophiles, with an optimum range of growth 45–60°, and appear in abundance at the high-temperature phase of the compost, with a profuse production of aerial mycelium and spores. Spore germination is induced by heat activation, 5 min. at 85° securing growth under suboptimal conditions. Thin suspensions of spores in 1 % sucrose or in very dilute nutrient broth withstand 100° for periods of up to 45 min. Only very dense aqueous or saline suspensions are tolerant of these exposures. Surface growth on cellophan bearing a high density of aerial mycelium and spores withstands dry heating at 100° for 150 min. or at 106° for 5 min.

STUDIES ON THE METABOLISM OF STREPTOMYCES GRISEUS IN RELATION TO THE PRODUCTION OF STREPTOMYCIN

A synthetic medium inducing high streptomycin production was evolved by studying growth factor and nitrogen requirements of the mold Streptomyces griseus. It was concluded that mycelium growth and streptomycin production do not necessarily parallel each other. Histidine appeared to affect both streptomycin and mycelium formation and was essential in any amino acid combination to induce either a high mycelium or streptomycin yield. Valine was shown to stimulate streptomycin synthesis and aspartic or glutamic promoted only mycelium production. Experiments were done to show which metabolic changes in the medium could be associated with growth and which with the antibiotic production.The effect on the mold of high concentration of sodium chloride was investigated. It was found that by reducing the amount of salt in the nutrient media, the greater part of the streptomycin could be recovered from the mycelium instead of the medium. It appears that the antibiotic is a product of intracellular synthesis, since ions of the lyotropic series affecting the permeability of the cellular membrane affect the distribution of the antibiotic between medium and mycelium.

Differentiation of the Vegetative and Sporogenous Phases of the Actinomycetes: 2. Factors affecting the Development of the Aerial Mycelium

SUMMARY: When first isolated on soil extract agar, soil actinomycetes consistently produce aerial spores in surface colonies. They retain this property when maintained in sterile soil, or when grown on washed suspensions of common soil bacteria, living or dead, in a water agar medium. In soil, when the composition, moisture content and temperature are kept constant, the initial stimulus towards the production of aerial mycelium is free access of air: the quantity and nature, vegetative or sporogenous, of the inoculum, and, within a broad range, the pH of the soil are of minor importance. Once growth is established, the next most important factor stimulating sporulation in the soil is also physical, namely dehydration. In natural and sterilized soils of different origins, and in a ‘Synthetic’ soil containing 250 p.p.m. of nitrogen as nitrate, the modes of growth of different actinomycetes strains are similar, and generally uncharacteristic of their species.

Carbohydrate Nutrition of Rhizopus suinus

1. Extraction of dextrose, levulose, galactose, and sucrose with acetone, alcohol, and ether resulted in increased mycelial production by Rhizopus suinus. 2. Extraction of dextrose with alcohol and ether resulted in increased mycelial production by this fungus. The increase was not so great as with the acetone-alcohol-ether extraction. 3. Recrystallization of dextrose from 80 per cent alcohol resulted in growth augmentation of about the same magnitude as that which resulted from the acetone-alcohol-ether treatment. 4. The presence of vitamin B1 (thiamin, aneurin) in reagent-grade dextrose was shown by the thiochrome oxidation method. Removal of traces of vitamin B1 from the sugars during the extraction process is possibly the cause of the growth phenomena. 5. The extract of dextrose contains a substance which, when concentrated by evaporation, promotes the vegetative growth of R. suinus if it is added to the culture medium. The substance was demonstrated, by growth experiments in which the nutrient solution was supplemented with the ash obtained from the unpurified dextrose, to be an ash constituent. 6. Under the conditions of the extraction, the removal of vitamin B1 would be more extensive than the removal of the ash constituents, the influence of the removal of the thiamin consequently being more effective in increasing the growth of R. suinus than the removal of the small amount of ash constituents in decreasing the growth of the organism. When the extract is concentrated, however, the influence of the ash element(s) on mycelial production is much greater than the influence of the vitamin B1, and the result is growth augmentation.

A STUDY OF CERTAIN SPECIES OF THE GENUS SCLEROTINIA

SUMMARY Investigations were carried out on Schrotinia serica, two strains of S. Sclerotiorum de Bary, five strains of S. Trifoliorum Eriks., two forms of S. minor Jagger, four isolations of a Sclerotinia from Vicia Faba considered to be a variety of Sclerotinia Trifoliorum, and a variant which arose from one of these isolations. Their pathogenicity to several different plants was tested and the fungi were found to fall into three groups: (1) S. Sclerotiorum and S. minor, (2) S. Trifoliorum and its variety Fabae, and (3) S. serica. A variant with light brown sclerotia which arose from S. Trifoliorum var. Fabae differed from the parent form in pathogenicity. Ascospores of S. Sclerotiorum, S. minor and S. Trifoliorum did not infect healthy leaves. The production of mycelium by sclerotia in the soil was not observed. S. serica differed from the other fungi in that it produced numerous apothecial stipes and several apothecia in test‐tube cultures. Exposing sclerotia to different conditions of temperature and moisture after their removal from culture and before their burial in damp sand did not hasten apothecial production. Sclerotia formed in cultures grown over a wide temperature range produced apothecia when subsequently buried in damp sand. Single‐spore lines of S. serica, S. Sclerotiorum, S. minor and S. Trifoliorum produced apothecia. Apothecial production took place over a wide temperature range. Apothecia of one form of S. minor arising from sclerotia formed on sterilized vegetables were larger than those from sclerotia formed on malt‐extract. The dimensions of the apothecia are given and a description of the apothecia of S. Sclerotiorum, S. minor, S. Trifoliorum and S. Trifoliorum var. Fabae. Measurements are given of asci and ascospores. The minimum, maximum and optimum temperatures fpr linear spread of mycelium are given: also the time taken by cultures to reach a diameter of 6 cm. at 207deg;C. The view is expressed that such data should not be used for differentiating species. S. serica spread more slowly than the other species. The variant of S. Trifoliorum var. Fabae had different temperature relations from the parent form. A brief description is given of the cultural appearance of S. Sclerotiorum, S. Trifoliorum, S. minor, S. Trifoliorum var. Fabae and its variant. The classification of the fungi is discussed.

Culture Studies of Psilocybe coprophila

1. Psilocybe coprophila Fr. has been found to be a heterothallic species producing two strains of primary mycelium, the union of which is necessary for the production of a secondary mycelium with clamp connections, and of basidiocarps. 2. The capacity for the formation of abnormal basidiocarps is greater in some crosses than in others, and is transmitted from generation to generation, although not as a simple Mendelian character. 3. Oidia are produced on both primary and secondary mycelia. Those produced by primary mycelia germinate to form haploid mycelia of the same strain as the parent culture. Those produced by secondary mycelia sometimes germinate to form diploid mycelia. At other times they germinate to form haploid mycelia, segregation of nuclei occurring before the oidia are produced. This segregation seems to take place less readily in cultures of polysporous origin than in a diploid mycelium formed by crossing two primary strains.

Production of Mycelium by Oidium Albicans

In a previous report1 are detailed experiments that resulted in the production of mycelium by Oidium albicans in a watery extract of carrots. The following experiments were undertaken to determine what constituent in the carrot influences mycelial production. Carrot infusion was prepared by macerating about 800 gm. of carrots in 250 c c. of distilled water for 48 hours at room temperature. This extract was then sterilized and dialyzed through parchment paper at room temperature against 750 c c. of distilled water until the dialysate gave a positive Molisch reaction for carbohydrates. This solution is called extract 1, and contains some of the carbohydrates and salts present in carrots. TABLE i