Developmental change of the composition and content of the chitin-glucan complex in the fungus Aspergillus niger

The change of the content and composition of the chitin-glucan complex (CGC) of the ascomycete Aspergillus niger during its development has been studied. In submerged mycelium, the complex is dominated by glucan, whereas chitin is predominant in sporophores and spores. The highest CGC content has been noted in sporophores in the terminal phase and in submerged mycelium in the idiophase; i.e., before the formation of dormant cells. On the grounds of the correlation of the content and composition of lipids, protecting carbohydrates, and CGC, it is suggested that cell wall structural polysaccharides are involved in biochemical adaptation to adverse factors.     

Lipid content during sexual development in the homothallic mucor Zygorhynchus moelleri

In Zygorhynchus moelleri, a homothallic Mucor, triglycendes are the main components of chloroform/methanol extractable lipids. The triglycerides accumulate in the aerial hyphae, particularly in the developing zygospores and in the lateral suspensors, but only after zygospore maturation. They are probably transported from the submerged mycelium to the aerial hyphae. Most of the fatty acid synthetase activity is found in the submerged mycelium. The fatty acid composition of the triglycerides does not change appreciably during sexual development. No influence of trisporic acids has been found on triglyceride synthesis or transport.     

Volatile compounds from the mycelium of the mushroom Agaricus bisporus

The pattern of volatiles from the mycelium of two commercial strains of Agaricus bisporus, grown in axenic culture on a semi-synthetic medium, was found to be broadly similar to that of the volatiles identified from sporophores. Tetrachloro-1,4-dimethoxybenzene, a known secondary metabolite of several Basidiomycetes, was found in the mycelium though not in the sporophores. [³⁶Cl]Tetrachloro-1,4-dimethoxybenzene was obtained when sodium [¹³Cl]chloride was added to the medium.     

Optimization of nutrient medium for submerged cultivation of Ganoderma lucidum (Curt.: Fr.) P. Karst

The dependence of the amount of the grown vegetative mycelium of Ganoderma lucidum on the composition of the nutrient medium has been studied under conditions of submerged cultivation. The medium was optimized using full factorial and steepest ascent experimental designs. The addition of two carbon sources to the medium considerably improved the submerged growth of the mushroom. An optimized medium provided for a high yield (20-20.95 g/l) of the morphologically homogeneous mycelium and shortened the cultivation period to 3–4 days.     

Interrelation between the composition of lipids and their peroxidation products and the secretion of ligninolytic enzymes during growth of Lentinus (Panus) tigrinus

Lipid composition, intracellular products of lipid peroxidation (LPO), and the activities of extracellular enzymes were studied during submerged cultivation of the xylotrophic fungus Lentinus (Panus) tigrinus VKMF-3616D. The maximum secretion of ligninolytic enzymes during the phase of active mycelium growth correlated with increased content of readily oxidized phospholipids and unsaturated fatty acids and with low content of the LPO products. In the idiophase, which was characterized by lower excretion of extracellular ligninolytic enzymes, the content of more stable phospholipids, saturated fatty acids, and LPO products increased. A relationship between the composition of mycelial lipids and the secretion of ligninolytic enzymes was revealed.     

Composition and biological activity of submerged mycelium of the xylotrophic basidiomycete Lentinus edodes

The composition of submerged mycelium of Lentinus edodes, grown in laboratory fermenters, has been studied. The mycelium contained 23-24% proteins, 8-9% lipids, up to 1800 mg% phenolic substances, and a significant amount of inorganic substances, including calcium and iron. The fungus produced up to 5.0% intracellular and 3.5-4.0 g/l extracellular polysaccharides. The submerged mycelium stimulated the development of humoral immune response elicited by sheep red blood cells.     

Chemical Composition of the Edible Mushroom Pleurotus ostreatus Produced by Fermentation

Pleurotus ostreatus `Florida' was grown in submerged liquid culture. The biomass yield of the fungus, grown for 3 days in 2-liter fermentors, where the mycelial pellets measuring 5 mm in diameter were formed, was 11.7 g (dry weight)/liter. Comparing the chemical constituents of fruiting bodies produced on cotton straw and mycelial pellets revealed several similarities in total nitrogen, protein, glycogen, fatty acids, RNA, and ash content. Differences were observed in the contents of six amino acids. Although the total fatty acid content was similar, there were more saturated fatty acids in the mycelium. Cell wall composition, typical for basidiomycetes, was observed in both mycelium and fruiting bodies, with laminarin as the main polymer.     

Polymorphism of a culture of Actinomyces chromogenes var. trienicus, the producer of chromotrienine]

Variation of Actinomyces chromogenes var. trienicus 141-18 MSU, an organism producing trienin was studied under laboratory conditions. Nine stable spontaneous variants were isolated from the population of the initial culture when grown on Gause medium No. 1. The variants varied in differentiation and biosynthetic capacity, including such characteristics as size and form of the colonies, ability for formation of the aerial mycelium and its colour, capacity for sporulation, form of the spore chains and antibiotic production property. In the secondary structures the spores formed only in 6 variants out of 9 isolates. The spore form and spore membrane surface were close in all sporogenic variants, while there were significant differences in the structure of the sporophores. The variants forming the aerial mycelium of the same colour as that of the initial culture did not differ from it also by the nature of the spore chains (spirals with 3--8 turns). The variants with lighter aerial mycelium than that of the initial population formed straight sporophores or spirals with a small number of the turns (1--3). The comparative study of the antimicrobial spectrum of the variants and the component composition of the synthesized antibiotic complex showed that the asporogenic variants and dwarf variant signifcantly differed with respect to their phenotypes from the other cultures and had no antagonistic action. One of the assporogenic variants had only insignificant activity. All the spore forming variants did not differ from the initial culture in the complex of the antibiotics synthesized.     

Improvement of transglutaminase production by extending differentiation phase of Streptomyces hygroscopicus: mechanism and application

Streptomyces transglutaminase (TGase) is an important industrial enzyme that catalyzes cross-linking of proteins. It is secreted as a zymogene and then is activated by proteases under physiological conditions. Although the activation process of TGase has been well investigated, the physiological function of TGase in Streptomyces has not been revealed. In this study, physiological function of TGase from Streptomyces hygroscopicus was found to be involved in differentiation by construction of a TGase gene interruption mutation strain (Δtg). The mutant Δtg showed an absence of differentiation compared with the parent strain. Furthermore, the production of TGase was found to be increased with the extending growth arrest phase of mycelium in submerged cultures. Thus, to enhance yield of TGase, the mycelium differentiation of Streptomyces was regulated via low temperature stress in a 3-L stirred-tank fermenter. The production of TGase increased by 39 % through extending the growth arrest phase for 4 h. This study found that TGase is involved in Streptomyces differentiation and proposed an approach to improve TGase production by regulation of mycelium differentiation in submerged cultures.     

Protease activity inAgaricus bisporus during periodic fruiting (flushing) and sporophore development

Protease activity from sporophores and mycelium of the mushroomAgaricus bisporus was assayed during periodic cropping (flushing) and from sporophores during maturation. When the sporophores were harvested at the same developmental stages (pins or buttons) during cropping, proteolytic activity of the sporophores was found to oscillate with the same periodicity as the flushing cycle. For pin mushrooms (an early stage of development), peaks of activity occurred during the interflush periods, whereas for button mushrooms (a later stage of development) peak proteolytic activity coincided with the periods of maximum production. The proteolytic activity in the mycelium remained low and varied little with time. Of the tissues within the sporophore, gill tissue had a higher activity than the stipe or pileus. The changes in activity during sporophore development or maturation depended on the period in the flushing cycle when the sporophore was initiated. The results are discussed in relation to the possible role and regulation of flush co-ordinated proteases.     

Heterogeneity of the genus Actinomadura Lechevalier a. Lechevalier]

Studies of the morphology of Actinomadura spp. have shown that the genus comprises several morphological types of actinomycetes which differ by the presence and structure of the sporophores on the aerial and substrate mycelium. The actinomycetes differ also by the fatty acid composition of lipids in the mycelium, and can be subdivided into three groups: (1) fatty acids with a straight chain prevail; (2) fatty acids with branched chains of the iso- and anteiso structure predominate; and (3) fatty acids with straight and branched chains are contained in almost equal amounts. Therefore the genus separated on the basis of differences in the composition of the cell wall was heterogeneous according to the properties used in the taxonomy of the actinomycetes at the level of genus. These data prove that morphological properties have to be taken into account in the taxonomy of the actinomycetes.     

Optimization of nutrient medium for submerged cultivation of Ganoderma lucidum (Curt.: Fr.) P. Karst

The dependence of the amount of the grown vegetative mycelium of Ganoderma lucidum on the composition of the nutrient medium has been studied under conditions of submerged cultivation. The medium was optimized using full factorial and steepest ascent experimental designs. The addition of two carbon sources to the medium considerably improved the submerged growth of the fungus. An optimized medium provided for a high yield (20-20.95 g/l) of the morphologically homogeneous mycelium and shortened the cultivation period to 3-4 days.     

The Effect of Spaceflight on Growth of Ulocladium chartarum Colonies on the International Space Station

The objectives of this 14 days experiment were to investigate the effect of spaceflight on the growth of Ulocladium chartarum, to study the viability of the aerial and submerged mycelium and to put in evidence changes at the cellular level. U. chartarum was chosen for the spaceflight experiment because it is well known to be involved in biodeterioration of organic and inorganic substrates covered with organic deposits and expected to be a possible contaminant in Spaceships. Colonies grown on the International Space Station (ISS) and on Earth were analysed post-flight. This study clearly indicates that U. chartarum is able to grow under spaceflight conditions developing, as a response, a complex colony morphotype never mentioned previously. We observed that spaceflight reduced the rate of growth of aerial mycelium, but stimulated the growth of submerged mycelium and of new microcolonies. In Spaceships and Space Stations U. chartarum and other fungal species could find a favourable environment to grow invasively unnoticed in the depth of surfaces containing very small amount of substrate, posing a risk factor for biodegradation of structural components, as well as a direct threat for crew health. The colony growth cycle of U. chartarum provides a useful eukaryotic system for the study of fungal growth under spaceflight conditions.     

Composition and Biological Activity of Submerged Mycelium of the Xylotrophic Basidiomycete Lentinus edodes

The composition of submerged mycelium of Lentinus edodesgrown in laboratory fermenters was studied. The mycelium contained 23–24% proteins, 8–9% lipids, up to 1.8% phenolic substances, and a significant amount of inorganic substances, including calcium and iron. The fungus produced up to 5.0% intracellular and 3.5–4.0 g/l extracellular polysaccharides. The submerged mycelium stimulated the development of humoral immune response elicited by sheep red blood cells.     

Gibberellin-like Substances in the Sporophores of Agaricus bisporus (Lange) Imbach

Sporophores of cultivated Agaricus bisporus (Lange) Imbach,were shown to contain a gibberellin-like substance active inthe dwarf maize (d-5), -amylase and other bioassays. Ethyl-acetateextraction followed by paper, column, and thin-layer chromatographyrevealed the presence of one major active substance. Ficin hydrolysisof dried sporophore powder, after the complete removal of freesubstances, released more gibberellin-like substances, one ofwhich appeared identical to the free compound. The free substance was predominantly in the lamellae and residualpileus tissue. The major active substance released by ficinoccurred mostly in the lamellae but also in substantial equalamounts in both stipes and pilei. No activity was found in extractsof dikaryotic vegetative mycelium on malt agar. The level ofactivity in extracts from sporophores stored at – 20 °Cfell sharply after 7 d, and then remained constant over a periodof 6 weeks. The content of gibberellin-like substances in youngand old whole sporophores showed wide variation between experiments.In most cases young 2-d tissue had higher levels than old, 11-dtissue on a fresh-weight basis. Purified sporophore extractsand authentic gibberellins had no stimulating effect on growthof sporophores or of cultured vegetative mycelium. The inhibitorsof diterpene biosynthesis, CCC, and AMO-1618 induced a smallincrease in mycelial growth rate. Ethyl-acetate extraction ofhorse-straw compost prior to inoculation with Agaricus bisporusshowed the presence of gibberellin-like activity in significantamounts.     

The composition of fresh and stored oyster mushrooms (Pleurotus ostreatus)

Soluble carbohydrate, protein, polysaccharide and cell wall composition were assayed in freshly harvested Pleurotus ostreatus sporophores and those stored for 4 days at 2° or 18°. Mannitol and trehalose were present at 1.8 and 6.5% dry wt respectively in fresh sporophores, and at reduced levels in those stored at 18°. In sporophores stored at 2°, trehalose levels increased by up to 122%. Soluble polysaccharide appeared to be composed of glycogen-like material, which was susceptible to post-harvest breakdown, and components containing mannose and other sugars. The total protein content was 42% dry wt; no protein degradation was seen in sporophores stored at 2°, but about 25% of the protein disappeared during storage at 18°. Cell wall polysaccharide was utilised during storage. Respiration rate was about 8–10 ml CO₂/g dry wt/hr at harvest and declined to about 5 ml/g dry wt/hr after 40 hr storage at 18°.     

Enzymes of the xylotrophic basidiomycete Lentinus edodes F-249 in the course of morphogenesis

It has been shown that the fungus Lentinus edodes grown on a solid wort agar substrate produces intracellular enzymes, including Mn-dependent peroxidase, laccase, and tyrosinase as a family of isoforms. The composition of the complex (containing one to four forms of each enzyme) varied during the basidiomycete life cycle. The activity of oxidases was maximal at the stage of nonpigmented mycelium and at the stages of a brown mycelial mat and a fruit body. The activity of tyrosinase increased in the course of mycelium pigmentation and had two maxima: at the stage of a brown mycelial mat and at the stage of a fruit body. Laccase and tyrosinase activities were shown to increase sharply upon addition of oak sawdust extract to the culture medium as compared with the enzyme activities of mycelium grown on wort agar alone. It was established that the effect of phenol oxidase substrates on the growing mycelium consists in a twofold acceleration of the process of morphogenesis in the fungus L. edodes.     

Sporulation and the Macromolecular Composition of the Mycelium and Arthrospores of Geotrichum candidum

In submerged culture the mycelium of Geotrichum candidum breaks into fragments (arthrospores) which are either cylindrical or ellipsoidal in shape; the proportion of each spore type depends upon the glucose concentration in the medium. Above 0.2% glucose the ellipsoidal type prevails, whereas the cylindrical type is more abundant at lower glucose concentrations. The cylindrical spores and the mycelium have a very similar macromolecular composition, but the ellipsoidal spores have less RNA and protein and more carbohydrate than the mycelium.     

Polysaccharides of the fungus Cunninghamella japonica mycelium

Preliminary data on the polysaccharide composition of mycelium of the submerged grown fungus Cunninghamella japonica (synonymous with C. echinulata) were obtained. Mild acid hydrolysis of the mycelium led to formation of glucose, mannose and galactose, whereas acid treatment under drastic conditions afforded glucosamine as the hydrolysis product of chitin and chitosan, the summary content of both glucosaminoglycans being estimated as about 35%. Sequential treatment of the mycelium with hot water, 2% aqueous NaOH and 10% AcOH gave rise to several polysaccharide fractions, which were characterized by their monosaccharide composition. The yield ofchitosan extracted by AcOH was negligible. Additional purification of the fraction obtained by the action of alkali afforded a polysaccharide preparation, which was shown to be a linear (1-->3)-alpha-D-glucopyranan according to the data of chemical methods of structural analysis and NMR spectroscopy. It was concluded that Cunninghamella japonica differs from several other known representatives of Mucorales by the presence of this alpha-D-glucan, as well as by low content of chitosan and polyuronides.     

Polysaccharide composition of mycelium and cell walls of the fungus <Emphasis Type="Italic">Penicillium roqueforti</Emphasis>

Preliminary data on the polysaccharide composition of mycelium and cell walls of the fungus Penicillium roqueforti grown by the method of submerged cultivation have been obtained. Mild acid hydrolysis of both mycelium and cell walls results in formation of glucose, mannose, and galactose, while the treatment with acid under severe conditions results in formation of glucosamine, a product of chitin hydrolysis, the content of which is 19% in the cell walls. Several polysaccharide fractions were isolated from mycelium by successive extraction with hot water and 1 M NaOH at room temperature; their monosaccharide composition was characterized. The main fraction extracted by alkali, according to the data of NMR spectroscopy, mass spectrometry, and the chemical methods of structural analysis, is a linear α-D-glucopyranan, where the blocks of (1 → 3)-bound glucose residues are linked by single bonds (1 → 4). Water-soluble polysaccharides contain the linear blocks of (1 → 5)-bound residues of β-galactofuranose, most probably attached to the mannan core. The findings are of interest for chemotaxonomy of Penicillium fungi.