Showing papers on "Mycelium published in 1968"

CHEMICAL INDUCTION OF HAPLOID FRUITING BODIES IN Schizophyllum commune.

Abstract: The formation of fruiting bodies in the higher Basidiomycetes is the most dramatic expression of differentiation and morphogenesis that can be found among the fungi. Although fruiting is normally a property of dikaryotic mycelia,l 2 which in heterothallic species are formed from the interaction of compatible homokaryotic strains,3 it is by no means restricted to the dikaryophase. The extensive literature on the physiology, development, and genetics of Basidiomycetes contains numerous references to the sporadic formation of normal or subnormal fruiting structures on the haploid mycelia of a number of species.l' 4-9 Among the principal conditions that have been reported to trigger fruiting body development in haploid mycelia are mycelial aging,' nutrient exhaustion,s and mechanical injury.' Occasional reports have also indicated that chemical substances, e.g., the metabolic products of unrelated species of microorganisms, can initiate the process of fruiting.'" 11 Moreover, the specific occurrence of haploid fruiting in individual strains of any one species and its absence in other such strains have implicated an important genetic component in the control of the process.l, 7" 9 In all these cases, to be sure, full expression of the haploid fruiting response has required appropriate environmental conditions of growth, e.g., low CO2 tension, adequate illumination, suitable limits of pH and temperature, and an adequate supply of essential nutrients. The present study originated from the chance observation of an intermycelial reaction between a haploid strain of the Basidiomycete Schizophyllum commune and an imperfect fungus, Hormodendrum cladosporioides, which resulted in the induction of haploid fruiting bodies in the former. The present communication reports (a) the demonstration of a fruiting-inducing substance (FIS) in cell-free extracts of the isolate of Hormodendrum and the presence of materials with similar activity in certain stages of S. commune itself; (b) the physiological factors which affect the expression of FIS-induced fruiting; and (c) the preliminary attempts to characterize the inducing substance. Materials and Methods.-The mycelia of S. commune used for the major portion of this study were three homokaryons, isogenized, with the exception of their mating-type factors, by ten generations of backcrossing with strain 699, and heterokaryons derived from their intermating. In addition to this isogenic series, haploid strains of diverse origin and mating type were used for a number of tests. Some of these strains were obtained from Professor John R. Raper of Harvard University, whereas other strains were newly isolated from fruiting bodies collected in the vicinity of Bloomington, Indiana. The isolate of H. cladosporioides employed throughout this study was obtained as a laboratory contaminant and maintained on Difco's Cantino-PYG medium; this medium permitted little conidiation of the fungus and allowed maximal production of active FIS. All fruiting assays, test matings, and spore isolations were carried out on a medium (MM) that contained 20 gm glucose, 1.5 gm asparagine, 1.0 gm K2HP04, 0.46 gm KH2P04, 0.5 gnm MgS04-7H20, 120 1 g thiamine hydrochloride, and 17 gm agar per liter of dis

The oxidation of fatty acids by mycelium of Penicillium roqueforti.

Abstract: SUMMARY: Low concentrations of fatty acids with less than 14 carbon atoms were oxidized without a lag phase over a wide range of pH values by mycelium of Penicillium roqueforti. The effect of the fatty acids upon oxygen uptake by a given weight of mycelium, and the nature of the products of oxidation, were dependent upon the concentration and chain length of the fatty acid and the pH value of the system. The C9-C12 fatty acids which showed the greatest inhibitory effect were not oxidized to the corresponding methyl ketone with one less carbon atom in such high yields as the less toxic C6-C8 acids. The C6-C8 fatty acids markedly inhibited endogenous respiration at low pH values but this inhibition was reversed by increasing the pH value. The toxic effect associated with some fatty acids was less pronounced against mycelium which had been previously shaken over an extended period in phosphate buffer. It is suggested that the cellular regulation of fatty acid oxidation and methyl ketone formation involves deacylation of β-oxo acyl thiolester which provides an alternative means of recycling coenzyme A when oxidation of acetyl CoA is impaired.

Enduracidin, a new antibiotic. i:streptomyces fungicidicus no. b 5477, an enduracidin producing organism

Abstract: The mycological properties and antibiotic activity of strain No B5477, isolated from a soil sample collected in Nishinomiya, Hyogo Prefecture, were investigated This strain forms spiral sporophores, spiny spores, and gray aerial mycelium The culture is non-chromogenic Strain No B5477 was compared with known species and identified as a strain of Streptomyces fungicidicus Okami et al 19541) During the course of selecting a strain with high potency, a yellow mutant with yellowish aerial mycelium was obtained and its properties were investigated Streptomyces fungicidicus No B 5477 produces a new antibiotic, enduracidin, with a strong antibiotic activity against Gram-positive bacteria Acid-fast bacteria and phytopathogenic bacteria are also inhibited Enduracidin shows no cross resistance with the known antibiotics examined It is more active in a basic medium and therefore is a basic antibiotic The antibiotic activity of enduracidin was not affected by horse serum in the assay medium Its diffusibility was less than that of the other antibiotics examined The antibiotic activity of enduracidin was assayed by the paper disc method using Sarcina variabilis IFO 3067 as the test organism Enduracidin was produced mainly in the mycelium The fermentation conditions for production of the antibiotic were investigated

The effect of relative humidity and temperature on survival and growth of Botrytis cinerea and Sclerotinia sclerotiorum

Abstract: Tests with mycelium and conidia of five strains of Botrytis cinerea and mycelium of three strains of Sclerotinia sclerotiorum have shown that survival and growth of these organisms depended on rela...

A New Genus of the Actinomycetales: Microtetraspora gen.nov.

Abstract: SUMMARY: Two aerobic mesophilic microbial species of a new genus belonging to the family Streptomycetaceae of the order Actinomycetales are described under the name Microtetraspora (Microtetraspora glauca, type species). The microorganisms produced a filamentous growth which is differentiated into a vegetative and an aerial mycelium. The new genus is characterized by the formation of a short and sparsely branched aerial mycelium bearing at the end of short sporophores chains of four spores. Sporulation is not observed to take place on the vegetative mycelium. The genus Microtetraspora is widely distributed in the soil and has been isolated from many samples.

A new genus of the Actinoplanaceae: Planobispora, gen. nov.

Abstract: A new species of a new genus of the Actinoplanaceae is described, for which the name Planobispora longispora gen. nov. sp. nov. is proposed. The organism is a typical mesophilic, aerobic actinomycete, producing a filamentous growth which is differentiated into a vegetative and an aerial mycelium. The new organism is characterized by the formation of sporangia only on the aerial mycelium and by containing a longitudinal pair of motile spores.

Lipids produced by Epicoccum nigrum in submerged culture

Abstract: 1. The lipids of the red mycelium of the fungus Epicoccum nigrum Link were investigated. Four carotenoid pigments were isolated and identified as β-carotene, γ-carotene, rhodoxanthin and torularhodin. 2. For the first time rhodoxanthin was isolated as a fungal metabolite. 3. Linoleic acid was the major fatty acid in the total lipids. 4. Ergosterol was present in the lipids in the non-esterified form.

The control mechanism of sclerotial formation in Sclerotium rolfsii Sacc.

Abstract: SUMMARY: The distribution of [14C]-L-cysteine and [14C]iodoacetic acid in mycelium and sclerotia of Sclerotium rolfsii Sacc., and the effect of disodium ethylene-diaminetetraacetic acid (Na2EDTA), trans-1, 2-diaminocyclohexane-N, N, N', N'-tetraacetic acid (Chel. C.D.), potassium iodate and phenylthiourea on the formation of sclerotia by S. rolfsii were studied. [14C]-labelled iodoacetic acid accumulated specifically in the sclerotia, whereas [14C]-L-cysteine was equally distributed throughout the mycelium. Accumulation of iodoacetic acid at specific sites was observed even before the formation of the sclerotia. Most of the radioactivity of the fungal mycelium grown on [14C]iodoacetic acid was found in the cell-free extract, 93% of the radioactivity of the extract being associated with the ammonium sulphate-precipitated fraction. Na2-EDTA, Chel. C.D. and potassium iodate at 10-3M also induced sclerotial formation. The effect of Na2EDTA was eliminated by the addition of 3 × 10-5M-Cu2+, but not by Fe2+, Zn2+, Co2+, Mn2+, Ca2+ nor Mg2+. Phenylthiourea (10-3M) initiated sclerotial formation but inhibited further development and melanogenesis. It is suggested that sclerotial formation in S. rolfsii is induced by inactivation of a -SH + Cu2+-containing protein entity which acts as a repressor of sclerotial formation.

Production of a Capsular Polysaccharide by a Marine Filamentous Fungus

Abstract: The spent seawater medium of 4-day-old-cultures of the filamentous marine fungus Leptosphaeria albopunctata had a high viscosity after the fungus was collected by high-speed centrifugation. Microscopic examination of uncentrifuged mycelium suspended in India ink revealed that the viscosity resulted from capsular material. These capsules became disassociated from the mycelium during centrifugation. Precipitation of the medium of centrifuged cultures with 95% ethyl alcohol yielded a highly anthrone-positive polysaccharide material, composed of large amounts of glucose and minute amounts of mannose. Time course studies of the nutritional requirements for capsular polysaccharide production revealed that the capsular material was produced in large amounts, and on a wide variety of sugars, during the period of rapid growth, but was quickly degraded and presumably remetabolized in older cultures. The amount of capsular material produced was enhanced by NaCl concentrations above that of artificial seawater, and KCl could be substituted for NaCl. The salts MgCl(2) and CaCl(2) were also required for capsule production by L. albopunctata, although growth was obtained in cultures without added amounts of these constituents. The possible role of these salts in the metabolism of the fungus is discussed.

The effect of sterols on the metabolism of Pythium species.

Abstract: The growth of several Pythium species is increased between 65 and 100% if cholesterol is added to the growth medium. The optimum concentration is 15 mcg per ml. Mycelium of Pythium ultimum, in which cholesterol is present, incorporates glucose-U-14C and releases 14CO2 at a faster rate than the corresponding sterol free mycelium. In sterol containing cells, more 14CO2 is produced from a given amount of absorbed glucose-U-14C than in sterol free cells, there is thus in sterol containing hyphae a higher level of energy production. This condition can account for the increase in growth due to cholesterol. Only if sterols are present in the cellular membranes of Pythium species is the optimum synthetic capacity reached.

Isolation and culture of monokaryotic haplonts of Ustilago nuda, the role of proline in their metabolism, and the inoculation of barley with resynthesized dikaryons

Abstract: Spores of Ustilago nuda were germinated on nutrient medium containing benzoic acid or derivatives. These compounds inhibited mitotic divisions of the nuclei in the two dikaryons formed by one spore. After removal of the chemical from the medium, mitosis occurred and the four monokaryotic haplonts were isolated by microsurgery. The haplonts were cultured on media supplemented with L-proline, because all haplonts of (+) mating type, originating from spores collected in Europe, Asia, Africa, and North and South America, were found to be proline deficient. The gene controlling proline synthesis behaved as though it was identical with or part of the mating locus. Barley flowers at mid-anthesis were inoculated successfully with dikaryotic mycelium resynthesized from isolated haplonts.

The incorporation of cholesterol by Pythium sp. PRL 2142, and some of its effects on cell metabolism.

Abstract: A method is described by which cell wall, protoplasmic membrane, and intracellular membrane fractions of Pythium sp. PRL 2142 were separated. Distribution of cholesterol among these fractions was determined. The major part of the cholesterol taken up by the cell was incorporated into the protoplasmic membrane, and the rest into the intracellular membranes. Other evidence, though indirect, that cholesterol is incorporated into the cell membranes includes: (a) the leakage of cell material from mycelium grown in the presence of cholesterol is much lower than that from mycelium grown without cholesterol; (b) four polyene antibiotics increase the leakage of cell material from mycelium grown in the presence of cholesterol but have no effect on mycelium grown in the absence of cholesterol. Some other effects of cholesterol on cell behavior are: (a) increase of the lactic acid and acetoin production and decrease of the oxygen consumption; (b) decrease of cellulase and laminaranase activity with a simultaneous eff...

The effect of chloramphenicol on growth and mitochondrial structure of Pythium ultimum.

Abstract: SUMMARY: Chloramphenicol was found to inhibit the growth of Pythium ultimum, showing a maximum dose-response at a concentration of 100 μg./ml. Mycelium grown in the presence of chloramphenicol 100 μg./ml., was devoid of the mitochondrial cytochromes aa 3 and b but contained increased cytoplasmic cytochrome c. Mitochondria in thin sections of hyphae grown in the presence of chloramphenicol resembled mitochondria in normal hyphae. In negatively stained preparations of isolated normal mitochondria stalked particles were observed on the cristae. These particles could not be demonstrated in mitochondria from hyphae grown in the presence of chloramphenicol 100 μg./ml.

Studies on the survival of Mycosphaerella pinodes and Ascochyta pisi

Abstract: SUMMARY Laboratory and field experiments on two pea-pod and leaf-spot pathogens, Mycosphaerella pinodes and Ascochyta pisi, have indicated that the former species may survive overwinter in soil whether introduced as pycnidiospores, mycelium, chlamydospores or sclerotia The survival of pycnidiospores appears to be due at least in part to their transformation into chlamydospores in the soil A pisi was much less successful in soil; the mycelium inoculum survived, somewhat sporadically, and spore viability was reduced, while the total number of spores declined markedly Investigations on the competitive saprophytic ability of these pathogens showed that by the agar plate method M pinodes could be classed as a moderately successful saprophyte, though the Butler and Park methods indicated only intermediate and poor success respectively A pisi was adjudged a poor saprophyte by all three methods Saprophytic growth and survival in soil of both fungi was generally better at 2 °C than at 15 °C

The Autolysis of Aspergillus flavus in an Alkaline Medium

Abstract: SUMMARY: The autolysis of Aspergillus flavus subjected to a combined action of a continuous flow of air and mechanical agitation has been studied. We have obtained a degree of autolysis amounting to 85%. The total loss of nitrogen in autolysing mycelium of A. flavus reached 82%, whereas the loss of phosphorus was 90% from the beginning of autolysis. Total carbohydrates were reduced from 524 mg./sample, at 0 day, to 119 mg./sample by the 16th day of autolysis, which represents a loss of 77%. Glucose was the only sugar found in significant amount in autolysing mycelium of A. flavus, being 96% the total loss. The concentration of mannitol decreased to nearly a third at the end of the log phase. The disappearance of this substance during pre-autolysis and autolysis amounted to 97.7% with respect to the maximum weight present at the 8th day of incubation. Fourteen different free amino acids were identified in the mycelium of Aspergillus flavus during the pre-autolytic and autolytic stages of growth. These amino acids increased their content between the 4th and the 6th days of incubation, to the highest concentration observed. Seventy-nine per cent of this maximum amount disappeared by the end of the log phase, whereas 78% of the remainder disappeared from mycelium during autolysis (16 days). From the total amount of bound amino acids in mycelium of A. flavus it seemed that the make-up of the mycelial protein does not undergo great changes in the interval between pre-autolysis and the initiation of the autolytic phase of growth.

Mercury-tolerant Pyrenophora avenae in seed oats

Abstract: Samples of Scottish and Ulster seed oats were examined for the effectiveness of treatment with an organo-mercurial fungicide in controlling Pyrenophora avenae Ito & Kuribay, the cause of leaf spot Seedling infection was initiated by mycelium on the caryopsis which was little affected by fungicide treatment Superficial mycelium on the lemma and palea was of minor importance and was more readily eradicated Several samples from both regions did not respond to fungicide treatment, and in one sample disease incidence was increased This was attributed to the presence of mercury-tolerant strains of the fungus There were indications that micro-organisms antagonistic to P avenae might have an inhibitory effect on the pathogen both in non-treated and mercury-treated seed

Movement of nutrients in fungi. I. The Mycelium

Abstract: Thirty-one species of fungi (representing 13 orders) were examined for their ability to grow from a nutrient medium onto a non-nutrient medium; 17 were capable of colonizing the deficient medium, 10 were not, and 4 were indeterminate. The ability to grow onto deficient medium appeared to be related to the natural habitat of the fungus rather than to taxonomic position. Experiments with isotopically labelled nutrients showed that both colonizing fungi and non-colonizing fungi were capable of some transport of nutrients, the difference between the two groups being one of degree. In transporting fungi, labelled nutrients were moved more rapidly when the fungus colonized a deficient medium than when it colonized a nutrient medium; this suggested that movement of nutrients is adaptive to some extent. The importance of the growing hyphal apex as a sink for nutrients was demonstrated.

Chloramphenicol inhibition of Pythium ultimum and Rhodotorula glutinis

Abstract: The growth of Rhodotorula glutinis is inhibited by both D-threo chloramphenicol and an L-threo isomer of chloramphenicol (lacking the dichloroacetyl group), causing an increase in the mean generation time, in a variety of media, approximately proportional to the concentration of antibiotic. The antibiotic is not removed from the growth medium in any quantity during this inhibition of growth. The oxygen uptakes of normal and chloramphenicol-grown cells of R. glutinis are similar when expressed on a dry weight basis. The oxygen uptake of normal and L-threo isomer-grown cells is strongly inhibited by antimycin A, whereas D-threo chloramphenicol-grown cells are unaffected. There was no evidence to suggest that any uncoupling of phosphorylation occurred with either isomer. Pythium ultimum mycelium also showed similar oxygen uptakes per unit dry weight whether grown in the presence or absence of D-threo chloramphenicol. The D-threo chloramphenicol-grown mycelium was also insensitive to antimycin A in contrast to the normal mycelium which was strongly inhibited. P. ultimum grows slowly in the presence of 100 μg/ml D-threo chloramphenicol in a glucose salts medium, but is completely inhibited by a similar concentration in a glycerol salts medium. The L-threo isomer does not inhibit the growth of P. ultimum.

Note on study of the sporulation of fungi: endotrophic sporulation in the genusPenicillium

Abstract: Conidiophore formation and sporulation can be induced inPenicillium sp. strain P 17 by an environmental factor—carbohydrate (carbon) starvation. Both surface and submerged mycelium, when transferred from synthetic medium to glucose-free salt solution, form conidiophores and sporulate, while in the control cultures on complete medium, vegetative growth continues. The time required for the formation of conidiophores, i.e. the induction interval, is 7–14 h and its length increases with the age of both surface and submerged mycelia. During the induction phase the mycelium undergoes autolysis, associated with degradation of energy motabolism involving the comsumption of reserve substances, a rapid drop in endogenous respiration and the endogenous reducing activity of the mycelium, a decrease in the labile phosphate concentration, proteolysis, an increase in the ammonia and orthopsphate concentration and exhaustion of readily oxidized amino acids from the pool. A transient increase in respiration occurs before differentiation of the conidiophores starts. During the second half of the induction phase, polyphenol substances and polyphenol oxidase appear in the mycelium.The enzyme is not induced by exogenous phenols. Its possible role in the sporulation of fungi is considered.

Microorganisms Existing on Leaves of Rice Plants and the Occurrence of Brown Leaf Spot

Abstract: In this paper microflora, especially of fungi, on the surface of apparently healthy leaves of rice plants is discussed. The second leaf from the top of variety Nakate Shin-Senbon was used for isolation, and many fungi, such as Candida, Rhodotorula, Penicillium, Alternaria, Aspergillus, and bacteria were isolated. Among them Candida sp. was most frequently isolated. The presence of Candida or other fungi in the conidia suspension of Cochliobolus miyabeanus did not disturb the conidia germination of the latter. However, if the mixed inoculation of Cochliobolus with Candida was performed to rice plants, number of the brown leaf spots decreased, representing about 50 per cent of the control. No microorganism, isolated from leaves of rice plants, inhibited the mycelial growth of C. miyabeanus on agar media.

The Establishment of Hop Tissue Cultures and their Infection by Downy Mildew Pseudoperonospora humuli (Miy. & Tak.) Wilson under Aseptic Conditions

Abstract: SUMMARY: Successful infection of hop tissue culture with Pseudoperonospora humuli was achieved. Infection was obtained from hyphae emerging from surfacesterilized systemically infected stems and petioles. Externally, infection was characterized by sterile aerial hyphae and sporangiophores, and internally by intercellular mycelium and intracellular haustoria. Although a considerable growth of mycelium into the agar medium was observed, it appeared to be dependent on the presence of host tissue. Attempts to establish axenic cultures of P. humuli were unsuccessful.

Developmental biology of sclerotia of Sclerotium rolfsii

Abstract: Sclerotial initials of Sclerotium rolfsii reached the maturation phase when transferred onto a new growth medium only if taken from original medium with their surrounding mycelium; but when transfe...

Metabolism of glucose-14C, pyruvate-14C, and mannitol-14C by Melampsora lini. II. Conversion to soluble products

Abstract: Mycelium of the flax rust fungus (Melampsora lini (Pers.) Lev.), grown on flax cotyledons in tissue culture, had a mean of 4.1 and a mean C6/C1 ratio of 0.14, measured after 4 hours in radioactive ...

Method of reducing raffinose content of beet molasses

Abstract: WHEN A-GLACTOSIDASE IS FORMED IN THE MYCELIUM OF MORTIERELLA VINACEA VAR, RAFFINOSEUTILIZER (ATCC NO. 20034), IT IS SUBSTANTIALLY FREE FROM INVERTASE. MYCELLIAL MATTER TAKEN FROM THIS MOLD AND PREPARATION CONTAINING THE ENZYME MAY THUS BE ADDED TO SUGAR BEET JUICE OR BEET MOLASSES FOR REDUCING THE RAFFINOSE CONTENT OF THE SAME, THEREBY GREATELY INCREASING THE RECOVERY OF SUCROSE CONTENT.

Activity of N-ribosyl-adenosine ribohydrolase in potato leaves in response to Phytophthora infection

Abstract: Early response of potato leaves to infection by the fungus Phytophthora infestans resulted in an accumulation of adenine in leaf tissue. Mycelium of P. infestans and ground potato leaf tissue converted adenosine to hypoxanthine and adenine, respectively, when fungal and host cells were incubated together. The influence of adenosine concentration, pH, and temperature on the conversion of adenosine to adenine by potato leaf extracts was examined; conversion occurred more rapidly at 70 °C than at 20 °C. The enzyme effecting the conversion was determined to be N-ribosyl-adenosine ribohydrolase. Preparations of this enzyme were chromatographed and retained their capacity to hydrolyze adenosine.

Movement of nutrients in fungi. II. The effect of reproductive structures

Abstract: Movement of labelled nutrients was investigated in a number of fungi which were producing reproductive structures (perithecia, basidiocarps, conidia, sclerotia). In every case markedly greater quantities of labelled nutrients were present in the reproductive structures than in the growing vegetative hyphae. In Phycomyces blakesleeanus, a species in which cytoplasmic streaming may be initiated by evaporation from sporangiophores, transport of label was found to occur at both low and high humidity, but there was faster movement at low humidity. It is concluded that transport of nutrients in the fungi may occur without the intervention of cytoplasmic streaming. The mechanism is unknown but it is apparently associated with a concentration gradient between sites of absorption from the substrate and sites of active metabolic removal at the growing apices or developing reproductive structures. Competition for nutrients between reproductive structures and vegetative hyphae may severely limit the ability of the mycelium to colonize non-nutrient substrates.

The pattern of asexual sporulation in Mycosphaerella ligulicola

Abstract: The asexual sporulation pattern of Mycosphaerella ligulicola Baker, Dimock & Davis was followed on agar culture At 23°C pycnidial initials were laid down only in mycelium which was 10–30 h old Spore production commenced in mycelium which was 18 h old and continued for at least 20 days Where septate spores were produced, evidence suggested that septa were formed after abstriction of the spores from the sporogenous cells of the pycnidium On agar medium and host leaf disks the spore number per unit area of culture increased with increase in temperature but spore size and the proportion of septate spores decreased The increase in spore number was due primarily to a higher productivity per pycnidium Total volume of the spore mass remained virtually unchanged over a wide temperature range Within limits determined by temperature, illumination caused a reduction in spore size which was associated with a reduction in total volume of the spore mass

Fatty acid composition of mycelium of Penicillium chrysogenum grown in different carbohydrates as a sole source of carbon.

Abstract: Der bisher wenig bekannte Fettsäuregehalt in Mycelien wird untersucht.

Pathogenicity studies with fusarium poae

Abstract: An isolate of Fusarium poae (Pk.) Wr. from diseased pea plants at Ottawa caused complete wilting and death of several varieties and species of legumes within 72 hours of root inoculation. Tip-wilting and severe stunting symptoms were produced on inoculated barley, but no symptoms developed on wheat and oats. A sterile filtrate from a suspension of conidia and mycelium was phytotoxic when applied to the roots of peas and beans. The fungus was able to persist for more than 8 weeks in soil containing decomposing pea plants.