The influence of medium on the chemical composition ofBlastomyces dermatitidis

Whole cells and cell walls of the mycelial and yeast forms ofBlastomyces dermatitidis grown in four different media were analyzed for differences in lipid, fatty acid, carbohydrate, and protein contents. The bound (saponifiable) fatty acids of yeast and mycelial whole cells (but not the cell walls) vary considerably in response to growth medium. The percentage of readily extractable lipid varied somewhat in whole cells. The percentage of carbohydrate and protein of whole cells and cell walls are little affected by the medium in which the cells are grown.     

Studies on the Metabolism of Aspergilli

Studies were made on the endogenous respiration of Aspergillus sojae K.S. Observing the changes of Kjeldahl-nitrogen in each fraction of the mycelial components, the author concluded that pool amino acids, bound amino acids, protein, nucleic acids and nucleotides covered whole of the nitrogenous reserves available for endogenous respiration in the mycelia. A study was carried out on the effect of preincubation with glucose or amino acids on endogenous respiration. Stimulation of either oxygen uptake, protein breakdown or ammonia formation was observed during respiration of the mycelia incubated with a suitable concentration of azide, 2,4-dinitrophenol, potossium fluoride, monoiodoacetic acid or ethylenediaminetetraacetic acid. Ammonia formation accompanied with endogenous respiration seemed to proceed inversely by the influence of energy yielding reaction.     

Mannitol Production by Pyrenochaeta terrestris

Pyrenochaeta terrestris (Hansen) Gorenz, J. C. Walker and Larson produces D-mannitol in the mycelium but not in the cutture filtrates when grown in a sucrose salts liquid medium. In the present study, P. terrestris was grown in stilt culture on a synthetic salts medium containing 30 g of sucrose per liter. After inoculation with a myceliat suspension, the mycelial mats were harvested and the dry weight and the amount of mannitol were determined. Maximum mycelial mat production occurred at 15 days after inoculation while the amount of mannitol was greatest at about 7 days after inoculation. The percentage of mannitot on a dry weight basis was maximal (20–25 per cent) within a few days after inoculation and decreased rapidly to 3–4 per cent at the time mycelial mat production was greatest. The same percentage of mannitot was produced when the fungus was grown in shake culture or when the sucrose was replaced by equivalent amounts of D-fructose, D-glucose, D-mannose, maltose, trehalose, and raffinose. Increasing the amount of sucrose or decreasing the amount of sodium nitrate increased the amount of mycelium produced but the percentage of mannitol in the mycelium remained about the same. Mannitot was reutilized when mycelial mats were transferred to a mineral medium without a carbon source. It was concluded that mannitot probably serves as a reserve carbohydrate in P. terrestris.     

Studies on the mechanism of action of sulfanilamide on mycelial felts of Rhizoctonia solani

Summary Sulfanilamide induced strong inhibitory effects on the growth, respiration and carbohydrate synthesis by mycelial felts of Rhizoctonia solani. The possible reasons for such inhibitory effects are discussed.The inhibitory effects of sulfanilamide were almost completely alleviated by the inclusion of p-aminobenzoic (PABA) acid in the culture medium of the fungal mats. R. solani normally produces certain amounts of PABA and its growth and metabolism is inhibited in presence of excess of it.     

SPORE GERMINATION AND CARBON METABOLISM IN FUSARIUM SOLANI. II. ENDOGENOUS RESPIRATION IN RELATION TO GERMINATION

Cochrane , V. W., Jean C. Cochrane , C. b . Collins , and F. G. Serafin . (Wesleyan U., Middletown, Conn.) Spore germination and carbon metabolism in Fusarium solani. II. Endogenous respiration in relation to germination. Amer. Jour. Bot. 50(8): 806–814. Illus. 1963.—Endogenous oxygen uptake by ungerminated macroconidia of Fusarium solani f. phaseoli is more than doubled by exogenous ammonium ion and is increased about 7-fold by germination. The respiratory quotient is halved by the provision of ammonia, which has essentially no effect on the endogenous formation of carbon dioxide. Stimulation by azide and 2,4-dinitrophenol suggests that the supply of phosphate acceptors regulates the rate of endogenous respiration. Mercurials poison the endogenous respiration, cyanide accelerates it, and iodoacetate, arsenite, fluoride, and chelating agents have little effect. Respiration is little affected by changes in pH, external phosphate, oxygen concentration, and spore density, within the limits tested. Spore lipid concentration is increased by cultivation in a high-glucose medium, but this variation in lipid content of spores docs not affect the endogenous Qo₂, nor does a high lipid content abolish the requirement for exogenous carbon for germination. Lipid utilization during endogenous respiration accounts for 37% of the loss in dry weight; lipid is also utilized during germination, but such utilization amounts to only about 5% of the carbon requirement. Neither mannitol nor nitrogenous compounds are significant substrates of endogenous respiration. The oxidation of the exogenous substrates tested does not measurably affect the concomitant rate of endogenous respiration. It is proposed that endogenous respiration can contribute to the synthetic processes of spore germination, although quantitatively insufficient to support germination without exogenous carbon. It is also questioned whether the respiratory quotient is an adequate index of the substrate of endogenous respiration.     

The carbohydrate metabolic end products of trematodes parasitic in cattle

The trematodes Eurytrema pancreaticum and Calicophoron ijimai during the incubation in vitro assimilated glucose from the incubation medium and utilized the endogenous glycogen. Final products of the carbohydrate metabolism in the calicophorones were lactic, acatic, propionic, isobutyric and alpha-methylbutyric acids; in the eurytremes they were lactic, acetic, propionic, isobutyric, alpha-methylbutyric, valerianic and capronic acids. The effect of anthelminthic preparations on the carbohydrate metabolism and its final products was investigated.     

Lipid metabolism and cell composition of the oleaginous yeast Apiotrichum curvatum grown at different carbon to nitrogen ratios

Apiotrichum curvatum ATCC 20509, an oleaginous yeast that can accumulate up to 60% of its cellular dry weight as intracellular lipid when grown with excess carbon, was grown in nitrogen-limited, balanced, and lactose-free medium with asparagine as nitrogen source and lactose as carbon source. Biomass and lipid accumulation were measured, cell composition was analyzed, and catalase activity was followed as marker enzyme for peroxisomes. The organism accumulated 54% of its dry weight as total cellular lipid when grown under nitrogen limitation and accumulated only 20-25% of its dry weight as lipid when grown in balanced medium. When starved for carbon, cells utilized endogenous lipid and carbohydrate as carbon and energy sources; the intracellular contents of lipid and carbohydrate decreased by 31 and 26%, respectively. Intracellular carbohydrates also seemed to be used as intermediates for lipid accumulation and lipid turnover. Catalase activity was strongly induced (over 10-fold increase in specific activity) when cells metabolized endogenous lipid. The lipid content of cells was inversely related to catalase activity and to intracellular protein or total nitrogen content. Lipid content showed no correlation with intracellular carbohydrate content.     

A preliminary study of the applicability of sweet potatoes for mycological fat production

Summary For mycological fat production,Aspergillus nidulans andPenicillium lilacinum were grown on media made up of crushed and boiled sweet potatoes. Mycelial mats containing a fair amount of fat were obtained, namely, 15 % in case ofAspergillus and 24 % in case ofPenicillium. Media containing an external supply of glucose gave rise to increase in percentage fat in mycelium, but the amount of mycelium and consequently the total fat content decreased.Addition of sodium nitrate gave heavier mycelial mats but the total fat content could not be raised.Addition of potassium phosphate or magnesium sulphate or both to the sweet potato medium gave rise to heavier mycelial mats but with lower fat content.     

A chemically defined medium for cephalosporin C production by Paecilomyces persicinus

A chemically defined medium was developed for the biosynthesis of cephalosporin C by Paecilomyces persicinus Nicot strain P-10. Glucose served as the major carbon source and nitrogen was supplied by five amino acids, l-arginine, l-aspartic acid, l-glutamic acid, glycine and dl-methionine. Omission of any of the first four diminished or prevented production of cephalosporin C; omission of methionine did not. Methionine is not critical for the production of cephalosporin C in this defined medium. Production of the antibiotic was affected by the concentrations of inorganic salts employed. Biotin was required for growth and cephalosporin C synthesis. The addition of l-lysine precursors to the medium did not influence cephalosporin C levels and l-lysine itself inhibited antibiotic production. Known precursors of -lactam antibiotics as well as oleic acid did not affect biosynthesis of cephalosporin C. Chemical changes occurring in the defined medium revealed that glucose was efficiently utilized after 96 hours incubation whereas total soluble nitrogen levels increased following an initial sharp decrease. Mycelial weight and cephalosporin C production were both maximal after 96 hours incubation. Mycelial nitrogen was highest after 48 hours incubation whereas mycelial lipid levels were greatest after 72 hours.     

Effects of nutrient and light limitation on the biochemical composition of phytoplankton

Three marine phytoplankters (Isochrysis galbana, Chaetoceros calcitrans andThalassiosira pseudonana), commonly used in the culture of bivalve larvae, were grown in batch or semi-continuous cultures. Changes in protein, carbohydrate, lipid and some fatty acids were measured as growth became limited by nitrogen, silicon, phosphorus or light. Under N starvation (2 d) the % lipid remained relatively constant, while% carbohydrate increased and% protein decreased in all 3 species compared to cells growing under no nutrient limitation. Under Si starvation (6 h) there was no change in lipid, protein or carbohydrates. The amount of two fatty acids, 20 : 53 and 22 : 63 remained relatively constant under N, P and Si starvation, exept for a sharp drop in the cells of P-starvedT. pseudonana. However, there were pronounced species differences withI. galbana containing significantly less 20 : 5 3 thanC. calcitrans orT. pseudonana. Under light limitation the amount of lipid per cell showed no consistent trend over a range of irradiances for all 3 species. The amount of N per cell (an index of protein content) as a function of irradiance, was relatively constant forI. galbana andT. pseudonana, while the amount of N per cell was lower under low irradiances forC. calcitrans. These examples of changes in protein, carbohydrate, lipid and certain fatty acids under nutrient (N, Si or P) or light limitation, emphasize the importance of knowing the phase (e.g. logarithmic vs stationary) of the growth curve in batch cultures, since the nutritional value of the phytoplankters could change as cultures become dense and growth is terminated due to nutrient or light limitation.Presented at the XIIIth International Seaweed Symposium, University of British Columbia, Vancouver, Canada, August 1989.     

Lipid profile of Pleurotus sajor caju

The lipid profile of Pleurotus sajor caju was studied in relation to mycelial and sporophore growth and different cultural factors. The growth was characterised by lipid synthesis during mycelial growth and utilisation during sporophore growth. The degree of instauration increased during mycelial growth and decreased during sporophore formation. The fatty acid composition of mycelium and sporophore was similar, linoleic acid (C_18:2) being the most dominant acid in both. C:N ratio had a significant (P<0.05) positive effect on mycelial dry weight; however, per cent total lipids was similar. Non-polar lipids became more unsaturated as the temperature was raised from 10° to 25°C and pH from 3.0 to 6.0, but declined when the cultures were aerated. Mycelial dry weight increased significantly (P<0.05) when the liquid medium was supplemented with lipids. In general, fatty acids with carbon chain length C₁₆ and C₁₈ stimulated the growth of mycelium. Supplementation of solid substrate (cotton seed hulls) with safflower oil, soybean oil or rice bran significantly (P<0.05) increased the yield of sporophores. Total lipids and ratio of non-polar to polar lipids were not affected by lipid supplementation.     

Utilization of some monosaccharides by two species of Colletotrichum

Summary Utilization of 8 monosaccharides, viz., glucose, fructose, galactose, mannose, sorbose, arabinose, xylose and rhamnose, by some plant pathogenic isolates ofColletotrichum gloeosphorioides andC. dematium has been studied with the help of paper chromatography. Among hexoses, the rate of utilization of glucose, fructose and mannose was fast, whereas, that of galactose was comparatively slow. The rate of assimilation of sorbose was very slow at early stages of incubation, although at later stages this rate showed marked enhancement. The pentoses were utilized readily. The dry weight of mycelial mats showed an increase up to the end of final incubation period (15 days), on sugars which were slowly assimilated. In cases where the sugars were consumed up rapidly, the dry weight at later stages of incubation either became nearly stationary or recorded slight fall.     

丝状真菌被孢霉产生油脂的研究

被孢霉的三个菌株Mortierella sp.M10,M13与M14生长在以葡萄糖为碳源、尿素为氮源的液体培养基中,所得到的菌丝体内堆积含γ-亚麻酸的油脂。油脂产率以M10菌株为高,而油脂中的γ-亚麻酸含量却以M14菌株为高。这种油脂的脂肪酸中,所含饱和脂肪酸主要有豆蔻酸(C14:0),棕榈酸(C16:0)和硬脂酸(C18:0);所含不饱和脂肪酸主要有棕榈油酸(C16:1),油酸(C18:1),亚油酸(C18:2)以及γ-亚麻酸(C18:3,n-6)。上述被孢霉菌株的培养物接种在含葡萄糖、尿素的培养基中生长大约48小时后,菌丝体顶端细胞形成鼓胀球状,此后仍继续胀大。菌体细胞形态的这种特异变化,可能与胞内油脂的累积有关。     

Invasiveness of Campylopus introflexus in drift sands depends on nitrogen deposition and soil organic matter

Question: Does the neophyte moss Campylopus introflexus invade more often in drift sand pioneer vegetations under high nitrogen (N) deposition? Location: Fourteen inland dune reserves in The Netherlands over a gradient of atmospheric N deposition. Methods: A transect study, dispersal experiment and culture experiment were carried out. In the transect study, the establishment of C. introflexus and lichens was measured in pure mats of Polytrichum piliferum, an early succession stage. The overall presence of C. introflexus in the area was also estimated. In the dispersal experiment, fragments of C. introflexus and lichen species were sown in P. piliferum mats at two sites with high and low N deposition. In the culture experiment C. introflexus fragments were grown on soil with different carbon (C) content and N dose. Results: The Campylopus:lichen ratio was positively correlated (r²=0.61) with the atmospheric ammonia concentration. Campylopus began to dominate at an ammonia air concentration of 7 μg m^?3, correlated with the overall presence of the species in the sites investigated. Survival of sown Campylopus fragments was significantly higher and the endangered lichen Cladonia strepsilis significantly lower in the site with a high ammonia concentration. Survival of Cladonia coccifera and Cladonia portentosa was high at both sites. Experimental growing of C. introflexus showed significant responses to both C content and N, although C content showed the strongest effect. Conclusions: Growth of C. introflexus is affected by soil C content and N deposition. Inland dune reserves under high N deposition risk loss of lichen‐dominated vegetations because of moss encroachment.     

Macrocyclic trichothecenes produced by Stachybotrys isolated from Egypt and Eastern Europe

Twenty seven isolates of Stachybotrys chartarum, S. albipes, S. kampalensis and S. microspora from Egypt and Eastern Europe were tested for production of macrocyclic trichothecenes. Twenty of the 27 isolates, grown on rice seeds, were toxic to brine shrimp larvae. Based on TLC and HPLC analyses, 5 macrocyclic trichothecenes (verrucarin J, roridin E, satratoxins F, G & H) as well as trichoverrols were identified. When grown in liquid culture on rice extract medium, only 3 isolates were toxic and produced verrucarin J, roridin E and satratoxins G & H. Extracts from mycelial mats were more toxic than culture filterates of two isolates grown on rice extract and both contained the same macrocyclic trichothecenes (285.5 mg/4 L), in addition to trichoverrols A & B (31 mg/4 L) found in mycelial mats only. When grown on 3% sucrose Czapek's medium supplemented with peptone and yeast extract (still cultures), all isolates were non-toxic to brine shrimp and no trichothecenes could be detected in the extracts.     

Synchronous Conidiation of Piricularia oryzae by the Replacement Culture

For the purpose of studying the mechanism of conidiogenesis in Piricularia oryzae, methods were developed to separate the phase of mycelial growth from that of conidiation and also to evaluate them quantitatively.

When P. oryzae was grown on media with low carbon : nitrogen ratio and high nitrogen concentration, conidiation did not take place, in spite of its vegetative growth. Conidiation occurred in a very short period of time when the above mycelia were replaced on nutritionally poor media. Cellophane membrane was overlaid on solid medium and conidia were spread uniformly. Evenly grown mycelial mat which could be easily transferred onto the post-culture medium was obtained. As the preculture medium, MSA medium with carbon: nitrogen ratio of 6.3 and nitrogen concentration of 1.5 g/liter was used. The evenly grown mycelial mat was cut into small square mats of 1.44 cm² each and the small square mycelial mats were transferred onto the post-culture medium together with the cellophane membrane. The conidiation took place in the post-culture and the vegetative growth in the preculture and the conidiation in the post-culture could be observed separately and quantitatively.

Conidiation did not occur at all in the preculture and the degree of conidiation which took place in the post-culture varied according to the precultural conditions. This means that it is a certain state of physiological condition in the preculture which determines the degree of conidiation in the post-culture. The authers designated this state of physiological condition as the “latent activity of conidiation” (LAC). For the purpose of the quantitative estimation of this activity, we expressed LAC in terms of the degree of conidiation in the post-culture under a defined cultural condition. The LAC was subject to change very easily, declined rapidly and disappeared upon prolonged preculture. Only young mycelia showed to have this activity.

The influences of the precultural condition on the development of the LAC and vegetative growth were generally parallel. However, the LAC was generally more sensitive to the environmental condition than the vegetative growth, especially to the temperature change.

The conidia formed were uniform in size and had high rate of germination. Several strains of P. oryzae tested showed very similar behavior.     

Oxidative metabolism of dermatophytes

A method for preparing young, actively respiring dermatophyte mycelia was obtained through the use of concentrated spore inocula and short growth periods in static culture. These hyphal elements were uniform in appearance, and vacuoles were absent. Concentrated mycelial suspensions were obtained which could be transferred easily and accurately. Glucose stimulated oxygen uptake in young mycelia which had been grown in a medium with low carbohydrate content. The level of endogenous respiration was affected by exogenous glucose only when this substrate stimulated oxygen uptake by less than 14%. Low nicotinamide adenine dinucleotide phosphate (NADP) dehydrogenase activity was noted in microconidia which have a low endogenous Q_o2 value, whereas the activity of this enzyme was greater in macroconidia and mycelia which possess higher endogenous Q_o2 values. Microsporum gypseum oxidizes 50% of exogenous glucose and assimilates the remainder. A large percentage of this substrate was assimilated into nitrogenous substances.     

Sporulation in Rhizopus sexualis and Some Other Fungi Following a Period of Intense Respiration

Rhizopus sexualis grown at 20° C. on liquid I per cent.malt or glucose-asparagine medium showed a peak of respiratoryactivity between 40 and 55 hours-after inoculation. Rate ofrespiration then fell until it reached a steady low level whichcoincided with maximum mycelial growth. Zygospore initiationoccurred at or just after the peak of respiration. At a low temperature (9° C.) or with high concentrationsof glucose the respiration peak was less marked and no zygosporesdeveloped. Single ‘plus’ or ‘minus’strains of the heterothallic species Mucor hiemalis and Phycomycesblakesleeanus showed a pattern of respiration and mycelial growthsimilar to that of R. sexualis but no zygospores were formed.Zygospores did not develop without a preliminary period of intenserespiration, but such a peak period could occur without beingfollowed by zygospore formation. A strain of Sordaria fimicola was grown at 25° C. on a syntheticmedium with 5.0 per cent. sucrose or glucose as source of carbon.Respiration reached a peak at approximately 4 and 5 days respectively,the actual peak value being twice as large on sucrose as onglucose. Dry weight of mycelium was greater on glucose thanon sucrose. Perithecia were formed only on the sucrose medium.Visible peri-thecial initials were first seen shortly afterthe occurrence of the respiratory peak. Mature perithecia werepresent 3 days later. The possible significance of these results is discussed.     

Induction of mycelial type of development in Candida albicans by low glucose concentration

A new simple method for synchronous germ tube production in Candida albicans has been described, based on the further incubation of cells released from stationary grown cultures in aerated mineral medium enriched with vitamins and low glucose concentration (5 mmol/l). At higher initial glucose (e.g. 250 mmol/l) the growth proceeded in yeastlike form. At low glucose concentration germ tubes developed at 28°C which is in contradiction with the results of many authors, considering 37°C besides other factors to be an inevitable requirement. On the other hand the cell population from stationary growth phase was the absolute prerequisite for massive germ tube production. Its importance for other inductive techniques is assumed.The report brings comparative results concerning the physiological and biochemical properties as well as the ultrastructure of the yeastlike and mycelial forms. Neither were found any differences in respiration intensity nor in respiration quotients during the development of both growth forms. Slight dissimilarities resulted from the incorporation experiments (using ¹⁴C labeled adenine, leucine and especially glycine). The mycelial cell walls were found to contain twice as much chitin as the yeastlike form.Some suggestion for further biochemical elucidation of dimorphism in Candida albicans and fungal morphogenesis generally are presented.     

The effect of pH value on the toxicity of culture filtrates ofHelminthosporium Sativum and on its possible correlation to extracellular nitrogen accumulation

Summary Helminthosporium sativum P.K. & B. was grown on modified Fries No. 3 medium buffered at pH 4.7, 5.5, 6.7, and 7.8. The nitrogen content of the culture filtrate, mycelial growth and the toxicity of the filtrate (as measured by its wilt inducing capacity to lupin seedlings) were traced over 24 days. The correlation between nitrogen accumulation and the toxicity of the filtrates was clear in case of media originally buffered at 4.7, 5.5 and 7.8. On the other hand, there was no correlation between growth of the mycelial mats and toxin production. The toxicity of the filtrate was attributed to two substances at least, one of unknown composition produced during the accelerated growth phase, while the other is nitrogenous and produced during the decline growth phase i.e. autolytic in nature. Acidity of the medium favoured toxin production during the first two weeks of incubation. The toxicity of the filtrate remained stable within a wide range of pH between pH 3–9.4.