Relation between ligninolytic and phospholipase activities in the fungus Lentinus tigrinus

Effect of hydrocortisone, NaF, and FeSO₄ on ligninolytic and phosphatase activity of the fungus Lentinus (Panus) tigrinus VKM F-3616D was investigated. Hydrocortisone and NaF were shown to inhibit the enzymes of the ligninolytic complex—laccase (EC 1.10.3.2), secretory peroxidase (EC 1.11.1.7), and Mn peroxidase (EC 1.11.1.13). FeSO₄ exhibited no significant effect on the activity of these enzymes. Decreased activity of the enzymes of the ligninolytic complex was associated with inhibition of the activity and changes in the substrate specificity of phospholipase A₂ (EC 3.1.1.4) in the presence of hydrocortisone of NaF. Cultivation of L. tigrinus in the presence of these compounds resulted in higher affinity of this enzyme to saturated fatty acids, while in the control and in the presence of FeSO₄ affinity to unsaturated fatty acids was higher.     

Influence of lignin and oxygen on the growth and the lipid formation of the fungus Lentinus tigrinus

During cultivation of the filamentous fungus Lentinus tigrinus on a medium containing lignin, a high oxygen content stimulated the growth of the fungus and contributed to the yield of lipids. A high content of phosphatidic acid and a reduction in the level of phosphatidylethanolamine and phosphatidylserine were first detected in the composition of phospholipids. Changes in the composition of neutral lipids, such as variation in the ratio of esterified and free sterols, have occurred; thus, the amount of sterol esters reduced simultaneously with a decrease in the content of free fatty acids. Based on the obtained results, the possible role of phosphatidic acid as a second messenger in the process of the consumption of lignin by the fungus Lentinus tigrinus is discussed.     

The effect of copper ions on the production of laccase by the fungus Lentinus (Panus) tigrinus

The basidiomycete Lentinus tigrinus was cultured in media containing copper ions added at different growth stages. Copper ions at increased concentrations decelerated of the fungal biomass accumulation. The later Cu²⁺ ions were added, the better the fungal mycelium developed, and the toxic effect of Cu²⁺ was less pronounced. The maximum laccase activity (47 U/ml) was observed in the presence of 1.5–2.0 mM Cu²⁺ added on day 4 of cultivation.     

Relation between the level of endogenous growth regulators and the differentiation of the fungusLentinus tigrinus studied in a synthetic medium

The fungusLentinus tigrinus was cultivated in a synthetic medium. During vegetative growth of mycelium and differentiation of fruiting bodies samples serving for determination of endogenous growth regulators were collected. The material was extracted with methanol, separated by chromatography and the isolated fractions were tested. Substances of auxin type were assayed with coleoptile segments of oat plants, gibberellins by measuring the hypocotyl growth in the lettuce and cytokinins from the degree of chlorophyll decomposition in the leaf segments of barley. Very low content of auxins was found in all phases of growth and differentiation of the fungus. The content of gibberellin substances was relatively high during the whole life of the fungus. The highest content is found in the vegetative mycelium and in the differentiated fruiting body, especially in the cap; it decreases during the differentiation of fruiting bodies. The content of cytokinins is equally high and the pattern of its change resembles that of the gibberellins. Its maximum is reached in young vegetative mycelium, it decreases when fruiting bodies are formed and when they are growing. Minimum is reached in the differentiated stalk, where also the amount of inhibitions is the highest. Experimental results show that during differentiation of fruiting bodies and their morphogenesis not only gibberellins and cytokinins are of importance, but also substances of an inhibitory character. A relatively high amounts of these substances was secreted into the cultivation medium. In a synthetic nutrient solution they may be easily demonstrated.     

The secotioid form of Lentinus tigrinus: genetics and development of a fungal morphological innovation

Secotioid fungi resemble gasteromycetes, but are presumably closely related to agaricoid fungi. Lentinus tigrinus is a wood-decaying mushroom that has both a secotioid and an agaricoid form. We examined ontogeny and heritability of the secotioid phenotype in L. tigrinus with a combination of formal genetic crosses, scanning electron microscopy, and macroscopic observation of cultured sporocarps. For F1 analysis, we crossed single-spore isolates (SSIs) representing four mating types derived from a secotioid dikaryon and four mating types from an agaricoid dikaryon. All F1 sporocarps had typical agaricoid morphology. For F2 analysis, 200 SSIs from one F1 sporocarp and 100 SSIs from another F1 sporocarp were backcrossed to tester SSIs from sporocarps produced by the parental secotioid dikaryon. Ratios of secotioid to agaricoid dikaryons thus produced were 47:49 and 84:109, which confirms previous reports that the secotioid phenotype is conferred by a recessive allele at a single locus (χ² = 0.0417, P > 0.05, χ² = 3.2383, P > 0.05, respectively). Early ontogeny of the secotioid form is indistinguishable from that of the agaricoid form. Later, the hymenophore is obscured by a weft of hyphae that proliferates from the margins of the developing lamellae. Longevity of the sporocarps and rate and duration of sporocarp growth are approximately equal in the secotioid and agaricoid forms. Developmental evolution of the secotioid form is interpreted as an example of von Baerian differentiation, rather than paedomorphosis, which has been implicated in evolution of other secotioid taxa.     

Increased secretion of lignolytic enzymes by the Lentinus tigrinus fungus after addition of butanol and toluene in submerged cultivation

We studied the effects of butanol and toluene on secretion of lignolytic enzymes by the Lentinus tigrinus fungus during submerged cultivation. Addition of butanol and toluene during the trophophase was followed by an increase in laccase and peroxidase activity of the culture and change in the composition of phospholipids and fatty acids. The ratio of phosphatidylcholine and phosphatidic acid decreased, while the amount of lysophosphatidylcholine, phosphatidylethanolamine, phosphoinositides, phosphatidylserine, and unsaturated fatty acids decreased. These changes resulted in an increase in the unsaturation index.     

The role of laccase and peroxidase of Lentinus (Panus) tigrinus fungus in biodegradation of high phenol concentrations in liquid medium

The possibility of the usage of Lentinus tigrinus fungus strain VKM F-3616D for biodegradation of high (up to 5%) phenol concentrations in liquid medium and the involvement of laccase and peroxidase in this process have been studied. L. tigrinus fungus was demonstrated to effectively digrade phenol with easy biomass separation from the liquid. Decrease in phenol concentration was accompanied by increased secretion level and laccase activity at the preliminary stages of biodegradation, while that of peroxidase was at the latest stages of biodegradation. These enzyme secretions in distinct ratios and consequences are necessary for effective phenol biodegradation. An effective approach for phenol concentration decrease in the waste water of smoking shops in meat-processing factories using L. tigrinus fungus was described.     

Effect of wood modification on lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus

Lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus cultivated on solid phase (modified and unmodified birch and pine sawdusts) were studied. The fungus grew better and consumed more readily the birch lignin than the pine wood. Peroxidase activity was higher in the case of pine sawdust; laccase and lignolytic activities, in the case of birth sawdust. Treatment with ammonia or sulfuric acid decreased lignin consumption by the fungus cultivated on either medium. Modification of sawdust by ultrasound increased lignin consumption and may be recommended for accelerating biodegradation of lignocellulose substrates.     

Modification of wood lignin by the fungus Panus tigrinus

The treatment of sawdust with the fungus Panus tigrinus VKM F-3616 D changed the contents of functional groups in lignin from wood raw material. These changes are accompanied by the release of carboxyl and phenyl hydroxyl groups involved in chemical bond formation between wood particles in pressed materials manufactured from wood wastes.     

Changes in endogenous growth regulators in nasturtium leaves during senescence

Summary By use of lettuce-hypocotyl and wheat-coleoptile bioassay, the presence of both gibberellin (GA)-like and abscisic-acid(ABA)-like components in acidic ethyl-acetate extracts of fully expanded nasturtium (Tropaeolum majus) leaves has been shown. During senescence of detached leaves there was a progressive decline in GA-like components and an increase in ABA-like components. Pretreatment of detached leaves with GA₃ or kinetin prevented changes in the levels of endogenous growth regulators and delayed senescence. The observations provide experimental verification for the concept that senescence is associated with changes in endogenous growth regulators.     

The endogenous allosteric regulators of receptors

The literature data devoted to endogenous allosteric regulators of membrane bound receptors are summarized in the present review. The allosteric processes are classified to (i) cooperative interaction, (ii) nonspecific, (iii) functional, and (iv) specific regulations according to target topography in a receptor. The specific endogenous allosteric regulators are described for GABAA, NMDA, muscarinic, nicotinic, serotonin, and opioid receptors. Substances of different chemical structure (peptides, lipids, and polycyclics) are able both to activate or inhibit binding and function of respective receptors. Some pathological processes appear to depend on endogenous receptor modulators. The role of the regulators is speculated in terms of receptor homeostasis, in particular, counteraction of receptor tolerance and/or sensitisation during physiological pulsation in a ligand' level in synaptic cleft.     

Optimal conditions for the fruit body production of natural occurring strains of Lentinus tigrinus

Lentinus tigrinus is a species with a fleshy pileus, strong odor and agreeable taste. In order to determine the optimal conditions for the production of this species, three substrates based on Salix sp. sawdust, wheat straw and supplements were tested in 500g dry weight bags at two different fruiting temperatures. Naturally occurring strains of this species were incubated at 30 degrees C. Primordium initiation could be observed 11-16 days after induction conditions began. This species produced highest yields with biological efficiency (BE) of 62% with supplemented sawdust at 25 degrees C. When bags were reduced to 100g dry weight, spawning run time was reduced from 28 to 30 to 10 to 14 days and BE increased more than 100%. L. tigrinus is a promising species with possibilities for commercial production.     

Gibberellins as endogenous growth regulators in green and brown algae

Summary Gibberellin-like activity was detected in extracts from Enteromorpha prolifera (Chlorophyta) and Ecklonia radiata (Phaeophyta). Material eluted from chromatograms of extracts and active in dwarf maize also brought about growth responses in the species from which the extract had been made. The responses were similar to those brought about by gibberellic acid. It is concluded that gibberellins are normally involved in regulating growth in green and brown algae.     

Kinetic studies on the redistribution of endogenous growth regulators in gravireacting plant organs

The kinetics of redistribution of endogenous indole-3-acetic acid, cis-abscisic acid and gibberellic acid (+gibberellin A₇) in gravistimulated plant organs were followed by immunoassay, during the latent period and the phase of gravitropic curvature. Whereas in maize coleoptile tips, endogenous indole-3-acetic acid accumulated in the lower half of the organ (ratio 65:35, in favour of the lower half) before bending occurred, it was not possible to detect any significant lateral asymmetry of any of the growth regulators assayed in gravitropically reacting root tips of Zea mays L. and Vicia faba L. nor in hypocotyls of Helianthus annus L. Also, no indication was obtained for an exchange of growth regulators between peripheral and central cell layers of the sunflower hypocotyl. Evidence is presented that changes in the properties of the epidermal or subepidermal cell layers located in the lower half of the horizontally placed sunflower hypocotyl are largely responsible for the gravitropic reaction. An alteration in the subcellular compartmentation of IAA may be involved in this process.     

Stimulation of the formation of fruiting bodies of the fungusLentinus tigrinus (Bull.) Fr. by growth regulators

Growth regulators, indole-3-acetic acid (IAA), gibberellic acid (GA₃), and kinetin (KIN), were used in different concentrations to stimulate the initiation and further development of the fruiting bodies of the fungusLentinus tigrinus. Vegetative mycelium of the fungus was cultivated on cellulose cylinders soaked with a synthetic nutrient solution or with a 3% malt extract. When the mycelium covered the surface of the cylinders, further cultivation was carried out in graduated concentrations of the growth regulators mentioned above. The number of developed fruiting bodies showed that the optimum IAA and GA₃ concentrations were in both media 300 p.p.m. The optimum concentration of kinetin was 400 p.p.m. The individual growth regulators influenced characteristically also the shape of the fruiting bodies and changed in them the natural level of endogenous growth regulators. The addition of IAA into the medium raised the level of endogenous auxins in the cap. The presence of gibberellic acid and of kinetic in the medium resulted in an increase in the level of these regulators in the fruiting bodies.     

Isolation and properties of peroxidase produced by the fungus Panus tigrinus

Synthesis of peroxidase and laccase by the fungus Panus tigrinus was significantly stimulated by addition of the lignocellulose substrate to the culture media. Peroxidase was isolated from the culture liquid and some properties of the enzyme were investigated. P. tigrinus peroxidase belongs to a group of extracellular peroxidases similar to the plant type peroxidases.     

The role of endogenous growth regulators in the differentiation processes of walnut (Juglans regia L.)

The character of endogenous growth substances was investigated in developing buds, young fruits and mature walnut leaves. The relatively high content of auxins and gibberellin-like substances was found by means of bioassays in the youngest primordia of vegetative buds. The level of auxins drops in the further course of primordia transformation into the staminate catkins. The development of leaf-buds is characterized by the accumulation of inhibitory activity as revealed by theAvena bioassay, whereas the data obtained from the lettuce bioassay indicate a pronounced stimulation. The onset of terminal bud development is also accompanied by inhibitions and it is only with pistillate flower differentiation that the temporary rise in auxin level is observed. An inhibitory activity was found in these extracts using lettuce bioassay. There is a relatively high auxin level in young fruits, mature leaves and resting buds during the mid-summer period whereas the accumulation of clearcut inhibitions is signalled by the results of lettuce bioassay. The regulatory role of growth substances in differentiation may be better understood during the second year as many leaf-abnormities appear only with the outgrowing of the bud. Abnormal catkins differ in the number of florets and stamens and some even bear pistillate flowers. Fruit development is liable to deviations in the early stages of differentiation. Abnormal fruits enable us to elucidate many structural peculiarities.