- [Show abstract] [Hide abstract] ABSTRACT: The work shows the ability of cultured Basidiomycetes of different taxonomic groups—Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifola frondosa—to recover gold, silver, selenium, and silicon, to elemental state with nanoparticles formation. It examines the effect of these metal and metalloid compounds on the parameters of growth and accumulation of biomass; the optimal cultivation conditions and concentrations of the studied ion-containing compounds for recovery of nanoparticles have been identified. Using the techniques of transmission electron microscopy, dynamic light scattering, X-ray fluorescence and X-ray phase analysis, the degrees of oxidation of the bioreduced elements, the ζ-potential of colloidal solutions uniformity, size, shape, and location of the nanoparticles in the culture fluid, as well as on the surface and the inside of filamentous hyphae have been determined. The study has found the part played by homogeneous chromatographically pure fungal phenol-oxidizing enzymes (laccases, tyrosinases, and Mn-peroxidases) in the recovery mechanism with formation of electrostatically stabilized colloidal solutions. A hypothetical mechanism of gold(III) reduction from HAuCl4 to gold(0) by phenol oxidases with gold nanoparticles formation of different shapes and sizes has been introduced.
- [Show abstract] [Hide abstract] ABSTRACT: Background and aims Azospirillum brasilense, which has the potential to stimulate plant growth, belongs to the group of plant growth-promoting bacteria. The lectin found on the surface of A. brasilense strain Sp7 has the ability to bind specific carbohydrates and ensures adhesion of the bacteria to the root surface. The aim of this work was to investigate possible inductive effects of the Sp7 lectin on the plant cell signal systems. Methods Enzyme-linked immunosorbent assay, spectrophotometry, and thin-layer and gas–liquid chromatography were used to determine the content of signal intermediates in the cells of wheat root seedlings. Laser scanning confocal microscopy was used to examine the localization of fluorescently labeled lectin on the plant cell. Results The Sp7 lectin acted on the signal system components in wheat seedling roots by regulating the contents of cAMP, nitric oxide, diacylglycerol, and salicylic acid, as well as by modifying the activities of superoxide dismutase and lipoxygenase. The revealed cell membrane localization of the lectin is of deciding importance for its signal function. Conclusions The results of the study suggest that the A. brasilense Sp7 lectin acts as a signal molecule involved in the interaction of growth-promoting rhizobacteria with plant roots.
- [Show abstract] [Hide abstract] ABSTRACT: The ability to reduce selenite (SeO3 (2-)) ions with the formation of selenium nanoparticles was demonstrated in Azospirillum brasilense for the first time. The influence of selenite ions on the growth of A. brasilense Sp7 and Sp245, two widely studied wild-type strains, was investigated. Growth of cultures on both liquid and solid (2 % agar) media in the presence of SeO3 (2-) was found to be accompanied by the appearance of the typical red colouration. By means of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and X-ray fluorescence analysis (XFA), intracellular accumulation of elementary selenium in the form of nanoparticles (50 to 400 nm in diameter) was demonstrated for both strains. The proposed mechanism of selenite-to-selenium (0) reduction could involve SeO3 (2-) in the denitrification process, which has been well studied in azospirilla, rather than a selenite detoxification strategy. The results obtained point to the possibility of using Azospirillum strains as endophytic or rhizospheric bacteria to assist phytoremediation of, and cereal cultivation on, selenium-contaminated soils. The ability of A. brasilense to synthesise selenium nanoparticles may be of interest to nanobiotechnology for "green synthesis" of bioavailable amorphous red selenium nanostructures.
- [Show abstract] [Hide abstract] ABSTRACT: We report for the first time that the medicinal basidiomycete Lentinus edodes can reduce Au(III) from chloroauric acid (HAuCl4) to elemental Au [Au(0)], forming nanoparticles. Several methods, including transmission electron microscopy, electron energy loss spectroscopy, X-ray fluorescence, and dynamic light scattering, were used to show that when the fungus was grown submerged, colloidal gold accumulated on the surface of and inside the mycelial hyphae as electron-dense particles mostly spherical in shape, with sizes ranging from 5 to 50nm. Homogeneous proteins (the fungal enzymes laccase, tyrosinase, and Mn-peroxidase) were found for the first time to be involved in the reduction of Au(III) to Au(0) from HAuCl4. A possible mechanism forming Au nanoparticles is discussed.
- [Show abstract] [Hide abstract] ABSTRACT: We report for the first time that the medicinal basidiomycete Lentinula edodes can reduce selenium from inorganic sodium selenite (Se(IV)) and the organoselenium compound 1,5-diphenyl-3-selenopentanedione-1,5 (DAPS-25) to the elemental state, forming spherical nanoparticles. Submerged cultivation of the fungus with sodium selenite or with DAPS-25 produced an intense red coloration of L. edodes mycelial hyphae, indicating accumulation of elemental selenium (Se(0)) in a red modification. Several methods, including transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and X-ray fluorescence, were used to show that red Se(0) accumulated intracellularly in the fungal hyphae as electron-dense nanoparticles with a diameter of 180.51±16.82 nm. Under designated cultivation conditions, shiitake did not reduce selenium from sodium selenate (Se(VI)).
- [Show abstract] [Hide abstract] ABSTRACT: under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source.
- [Show abstract] [Hide abstract] ABSTRACT: We report for the first time that edible medicinal xylotrophic basidiomycetes belonging to various systematic groups, such as Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, Grifola frondosa can reduce Au(III) from chloroauric acid (HAuCl4) to elementary Au [Au(0)], forming nanoparticles. Several methods, including transmission electron microscopy (TEM) and dynamic light scattering, were used in order to show that when the fungus was grown submerged, colloidal gold accumulated on the surface of and within the mycelial hyphae as electron-dense particles mostly spherical in shape with sizes ranging from 5 to 50 nm. The fungal phenol-oxidizing enzymes (laccases and tyrosinases) were found to be involved in the reduction of Au(III) to Au(0) from HAuCl4.
Dataset: Supplementary Material
Dataset: Supplementary Material
- [Show abstract] [Hide abstract] ABSTRACT: The present paper reports for the first time the transformation of an organic selenium compound into red selenium (Se), which causes the intense red pigmentation of Lentinula edodes (shiitake mushroom) mycelia. The biotransformation of 1,5-diphenyl-3-selenopentanedione-1,5 (diacetophenonyl selenide, preparation DAPS-25) was studied in liquid- and solid-phase cultures of L. edodes. In liquid culture medium, a red color develops in the mycelium at initial DAPS-25 concentrations equal to or higher than 0.1 mmol/l. The intensity and initiation time of coloration is Se concentration-dependent. Semiquantitative data obtained by physicochemical methods on the extent of Se and acetophenone production suggest that L. edodes is able to absorb and/or destruct this organic Se xenobiotic.
- [Show abstract] [Hide abstract] ABSTRACT: The possibility of application of the Pleurotus ostreatus D1-soil microflora to bioremediation of oil-polluted soils was studied. The fungus degraded mainly the aromatic fractions, whereas soil microflora intensely degraded paraffin and naphthene oil fractions. Introduction of the fungus Pleurotus ostreatus D1 to soil induces degradation of a wider range of oil hydrocarbons. It is reasonable to further investigate the discovered phenomenon in order to improve procedures of remediation of oil-polluted soils.
- [Show abstract] [Hide abstract] ABSTRACT: The lectin of Azospirillum brasilense Sp7 at 40 μg ml-1 elicited two peaks of induction of nitric oxide synthesis in the roots of wheat seedlings after 3 and 26 h of coincubation. The lectin of A. brasilense Sp7.2.3, a mutant defective in lectin activity, produced the same effect, but the activation of nitric oxide synthesis in the roots was less in the case of 26-h incubation. Exposure to the lectins for 3 h increased citrulline synthesis in the plant cell to the same extent. This finding indicated that the Azospirillum lectins activate nitric oxide production through the NO signal system of plants, thereby acting as inducers of adaptation processes in the roots of wheat seedlings.
- [Show abstract] [Hide abstract] ABSTRACT: Both quantitative and qualitative estimations of the basidiomycete Grifola frondosa lectin binding to the specific and non-specific polyclonal rabbit antibodies were attempted. The lectin complexation with homological antibodies was shown to be characterized by greater binding constants as compared to non-homological antibodies. Therewith the values of changes in standard free energy ∆G 0 displaying a strength of both complexes were essentially the same. The data obtained testify to universality of biospecific reactions “antigen–antibody” and “lectin–carbohydrate” at a molecular level, and could give new insight into the phenomenon of these biospecific interactions. The actual specificity in the above bio-recognition processes could differ from the results of in vitro assays using lectins, and, therefore, should be interpreted carefully when concluding on the lectins behaviour in living systems. KeywordsGrifola frondosa–Mycelial endolectin–Glycoprotein–Antigen–antibody interaction–Standard free energy–Binding constant
- [Show abstract] [Hide abstract] ABSTRACT: Along with a brief review of Lentinula edodes (shiitake mushroom) submerged cultivation history within the framework of important extracellular proteins biosynthesis, this study contains the authors’ own results. The possibility of regulating the lectin activity of shiitake using the synthetic components is shown. The time course of lectin production in culture liquid of L. edodes 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. A relationship between the chemical composition of nutrient medium, the activity of extracellular lectins of L. edodes, and the formation of pigmented mycelial film in liquid culture has been found. The formulation of medium, on which the brown mycelial film appears in several days of submerged cultivation, is proposed. The results obtained make a contribution to the present notion of biochemical processes that give rise to the occurrence of the aforesaid morphological structure of shiitake. Finally, two extracellular lectins from the submerged culture of L. edodes have been isolated and purified to homogeneity. Their physicochemical properties and composition have been studied. KeywordsExtracellular proteins-Lectins of higher fungi-Brown mycelial film-Molecular structure-Quantum chemical study
- [Show abstract] [Hide abstract] ABSTRACT: Lectins were extracted from the surface of nitrogen-fixing soil bacteria Azospirillum brasilense Sp7 and from its mutant A. brasilense Sp7.2.3 defective in lectin activity. The ability of lectins to stimulate the rapid formation of hydrogen peroxide related to increase of oxalate oxidase and peroxidase activity in the roots of wheat seedlings has been demonstrated. The most rapid induced pathway of hydrogen peroxide formation in the roots of wheat seedlings was the oxalic acid oxidation by oxalate oxidase which is the effect of lectin in under 10 min in a concentration of 10 μg/ml. The obtained results show that lectins from Azospirillum are capable of inducing the adaptation processes in the roots of wheat seedlings.
- [Show abstract] [Hide abstract] ABSTRACT: It was found that two cell-surface lectins isolated from the nitrogen-fixing soil bacterium Azospirillum brasilense Sp7 and from its mutant defective in lectin activity, A. brasilense Sp7.2.3 can stimulate rapid formation of hydrogen peroxide, associated with an increase in the activities of oxalate oxidase and peroxidase in the roots of wheat seedlings. The most advantageous and most rapidly induced pathway of hydrogen peroxide formation was the oxidation of oxalic acid by oxalate oxidase because in this case, a 10-min treatment of the roots with the lectins at 10 µg ml-1 was sufficient. The data from this study attest that the Azospirillum lectins can act as inducers of adaptation processes in the roots of wheat seedlings.
- [Show abstract] [Hide abstract] ABSTRACT: The activity of extracellular lectins of the basidiomycete Lentinus edodes has been shown to be related to the presence of definite double-charged metal cations in the synthetic liquid medium of cultivation. The effect of Fe 2+, Co2+, Ni2+ on the lectin activity has been demonstrated to change with a symbate character in respect to the energies of chelating reactions of metals hexaaqua complexes with the model ligand ethylene glycol, computed at the HF/3-21G(d,p), MP2/3-21G(d,p)//HF/3-21G(d,p) theory level. At the initial steps of the lectins biosynthesis, the above metals cations exert a much greater influence upon the lectin activity of L edodes, as compared to the results of subsequent interactions between the cations and proteins under study in the culture medium.
- [Show abstract] [Hide abstract] ABSTRACT: The complex of immunochemical methods was applied to study the ability of the lectin from the fungus Grifola frondosa (Fr.) S.F. Gray to interact with homologous and non-homologous rabbit and human polyclonal antibodies. The results of immunodot assay with the fragments of proteolytically cleaved antibodies demonstrated the binding of the lectin only with the Fab fragments (antigen-binding center) of homologous antibodies, which is evidence of specific “antigen-antibody” interaction. The revealed interaction of the lectin with non-homologous antibodies (rabbit antibodies to bacterial O-antigens and the commercial preparation of human g-globulin) is most likely accomplished due to the contact of the carbohydrate-binding region of the lectin with the carbohydrate moiety of the antibodies (“lectin-carbohydrate”). Immunofluorescence microscopy with homologous antibodies revealed that lectin was diffusely and unevenly distributed over the surface of the hyphae, forming agglomerates in the region of buckles and young shoots.
- [Show abstract] [Hide abstract] ABSTRACT: The white-rot fungus Lentinus edodes produced D-melibiose-specific lectins and two laccase forms in a lignin-containing medium. The maxima of laccase and lectin activities coincided, falling within the period of active mycelial growth. The enzymes and lectins were isolated and purified by gel filtration followed by anion-exchange chromatography. The L. edodes lectins were found to be able to stabilize the activity of the fungus's own laccases. Lectin activity during the formation of lectin-enzyme complexes remained unchanged.
- [Show abstract] [Hide abstract] ABSTRACT: We studied the role of lectin-carbohydrate recognition as a biospecific interaction during co-cultivation of the culinary-medicinal Basidiomycetes species Grifola frondosa and the diazotrophic bacterium Azospirillum brasilense Sp245 on an agar-supplemented medium. We showed that A. brasilense Sp245 and its Omegon-Km mutants, KM018 and KM139, defective in lipopolysaccharide (LPS) structure, whose LPSs contain O-specific polysaccharide (acidic OPS1, linear D-rhamnan), a hapten for the fungal lectin, are recognized by the fungus with the least antagonism, as distinct from mutants KM252 and KM348, which have neutral OPS2 and are inhibitory to the growth of the G. frondosa 0917 mycelium. Studying the influence of a pure lectin preparation on the motilities of these strains in a liquid medium, with the exception of the immotile KM018, revealed a decrease in the swimming speeds of Sp245 and KM139. The motilities of KM252 and KM348 were almost unaffected by the lectin. The obtained results attest to the involvement of biospecific lectin-carbohydrate interactions in the primary contact between the G. frondosa 0917 mycelium and the bacterium A. brasilense during co-cultivation. It is most probable that, in this case, the lectin acts as an attractant-like factor on the bacteria, thus ensuring the recognizing and protective functions of the fungus.
Russian Academy of SciencesMoskva, Moscow, Russia
Institute of Biochemistry and Physiology of MicroorganismsPushchino-na-Oke, Moskovskaya, Russia