Hemagglutinating activity of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler]

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains of Lentinus edodes was studied. The HA activity of CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures of L. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied, MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.     

Effect of culture medium composition on the activity of extracellular lectins of <Emphasis Type="Italic">Lentinus edodes</Emphasis>

The time course of lectin production in culture liquid of the basidial fungus Lentinus edodes strain F-249 in different media under submerged culture conditions was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and the pH of the culture medium. The lectin activity in culture medium was maximal when the fungus was grown in a medium containing L-arabinose as a source of carbon and L-asparagine as a source of nitrogen (C:N ratio, (9.5–12):1) on day 15–18 of culturing at pH 8.0–9.0.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 2, 2005, pp. 200–203.Original Russian Text Copyright © 2005 by Tsivileva, Nikitina, Garibova.     

Activity of <Emphasis Type="Italic">Lentinus edodes</Emphasis> intracellular lectins at various developmental stages of the fungus

We studied changes of the hemagglutinating activity of intracellular lectins of the basidiomycete Lentinus edodes (shiitake) at various stages of its morphogenetic development depending on erythrocyte type, growth medium, and lectin purification degree. Under certain experimental conditions, the specific lectin activity at the brown mycelium film stage exceeded the corresponding value for nonpigmented mycelium. The sensitivity of the lectins towards trypsin-treated rabbit erythrocytes was no less than a hundredfold higher than towards any other erythrocyte type studied. The general regularities of specific activity change did not depend on nutrient medium composition. With purification of intracellular shiitake lectins, their sensitivity to human erythrocytes decreased seventyfold or more, whereas their sensitivity to rabbit erythrocytes increased by the same factor.     

Lectin activity of Lentinus edodes

The hemagglutinating activity of submerged mycelium and culture liquid for four strains of Lentinus edodes (Berk.) Sing [L. edodes (Berk.) Pegler] was studied in the search for lectins. The hemagglutinating activity of culture liquid was substantially higher, compared with mycelium. The carbohydrate-binding capacity of the agglutinins was established, and the lectin activity of extracts from mycelia grown on several agar media was elucidated in relation to fruiting. The lectin activity of L. edodes was examined at different morphogenetic steps: mycelium, brown mycelial film, primordium, and fruiting body. Hemagglutination titers at the brown film step were higher than in the mycelium, whereas activity at the primordial and fruiting bodies steps decreased. Lectins seem to be involved in the formation of hyphal aggregates of brown mycelial film.     

Geropsychotropic properties of an antioxidant of the 3-hydroxypyridine class in an experiment

Comparative experimental investigation of albino male rats 3 and 16 months old has been performed. 16-month-old rats demonstrated age-dependent functional insufficiency in some behavioural tests. 2 month injection of 3-hydroxypyridine antioxidant (50 mg/kg/day) normalized memory function, motor skill learning and motor coordination function in 16-month-old rats.     

Germination of Basidiospores of Agaricus bisporus

The type of dormancy and conditions necessary for germination of Agaricus bisporus basidiospores were studied. Basidiospores failed to germinate on starvation agar and required the presence of carbon and nitrogen sources (asparagine and/or glucose) in the medium. Upon 3-week storage, basidiospores germinated after 4–5 days. Heat shock (20 min at 45°C) and decreased temperature facilitated activation of germination. Heterocyclic compounds stimulating germination of endogenously dormant spores, such as furfural, failed to activate germination. The data obtained suggested an endogenous dormancy of A. bisporus basidiospores differing from zygospores of Mucorales. Basidiospores contained 17–19% lipids with a composition of fatty acids differing from those of the pileus and stipe of the fruiting body. The soluble carbohydrates of the cytosol amounted to 12% dry spore weight and consisted of mannitol (74%) and trehalose (26%). Unlike basidiospores stored at 2°C, basidiospores stored for 5 months at 20°C lost their ability to germinate, which correlated with a decrease in the content of trehalose.     

Activity of Lentinus edodes intracellular lectins at various developmental stages of the fungus

We studied changes of the hemagglutinating activity of intracellular lectins of the basidiomycete Lentinus edodes (shiitake) at various stages of its morphogenetic development depending on erythrocyte type, growth medium, and lectin purification degree. Under certain experimental conditions, the specific lectin activity at the brown mycelium film stage exceeded the corresponding value for nonpigmented mycelium. The sensitivity of the lectins towards trypsin-treated rabbit erythrocytes was no less than a hundredfold higher than towards any other erythrocyte type studied. The general regularities of specific activity change did not depend on nutrient medium composition. With purification of intracellular shiitake lectins, their sensitivity to human erythrocytes decreased seventyfold or more, whereas their sensitivity to rabbit erythrocytes increased by the same factor.     

Relationship between the Carbohydrate Specificity of Lectins and the Carbohydrate Composition of the <Emphasis Type="Italic">Lentinus edodes</Emphasis> (Berk.) Sing [<Emphasis Type="Italic">Lentinula edodes</Emphasis> (Berk.) Pegler] Mycelium at Different Stages of Its Morphogenesis

The specificity of lectins from the basidiomycete Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] during solid-state cultivation was found to be maximum to carbohydrates detected in the pyri-dine-soluble fraction of mycelium during the brown mycelial film stage. The carbohydrate composition of the mycelium (i.e., its content of maltose, rhamnose, mannitol, and inositol) was found to be different upon normal fruiting body formation and when the nonpigmented mycelium produced defective fruiting bodies.     

Relationship between the Molecular Structure of the Nitrogen Source and the Activity of the Extracellular Lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] upon Submerged Cultivation

The activity of the extracellular lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] and the formation of a pigmented mycelial film by this fungus upon submerged cultivation in a synthetic medium were found to depend on the presence of some amino acids (particularly, asparagine) and Ca²⁺ and Mn²⁺ ions in the medium. Quantum-chemical calculations suggest that the different character of the interaction of amino acids with the aforementioned ions is due to differences in the hydrophobicity of the amino acids rather than to differences in the electron structure of the amino acid zwitterions.     

Effect of culture medium composition on the activity of extracellular lectins of Lentinus edodes

The time course of lectin production in culture liquid of the basidial fungus Lentinus edodes strain F-249 in different media under the conditions of submerged culture was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and pH of culture medium. The activity of lectin in culture medium was maximal when the fungus was grown in a medium containing L-arabinose as a source of carbon and L-asparagine as a source of nitrogen (C : N ratio, (9.5-12): 1)) on the day 15-18 of culturing at pH 8-9.