Biomedical Research Laboratories, Kureha Chemical Industries Co., Ltd., Tokyo, Japan.
Abstract
PSK (Krestin) is a protein-bound polysaccharide isolated from cultured mycelia of Coriolus versicolor in basidiomycetes. PSK is a biological response modifier which possesses unique characteristics. We investigated the effects of PSK on the immune response of aged C57BL/6 mice bearing a syngeneic transplantable tumor adenocarcinoma 755. (a) In C57BL/6 mice, the delayed foot pad reaction against sheep erythrocytes and resistance to syngeneic tumor challenge reached a peak when the mice were at 30 weeks of age, and decreased at 50-60 weeks of age. The serum of normal mice exerts a modifying effect on blastogenesis of lymphocytes to phytohemagglutinin. The positive effect reached a peak at 30 weeks of age, and thereafter declined with age. (b) When adenocarcinoma 755 was inoculated to C57BL/6 mice at 10-, 30- and 60-weeks of age, immune responses were depressed in 10-week-old and 60-week-old mice. PSK prevented such depression. However, in 30-week-old mice, tumor-induced suppression was slight, and administration of PSK to them increased proportion of mice which did not develop a tumor. (c) In 60-week-old tumor-bearing mice, the antitumor effects was increased with a combination of PSK and adoptive transfer of spleen cells from 10-week-old normal mice. The immune responses of mice, which change with the progress of age, are depressed by tumor burden. The administration of PSK to aged mice is effective to restore immune responses from tumor-induced suppression.
Battelle, Pacific Northwest Laboratories, Richland, Washington 99352.
Abstract
Coriolus versicolor has previously been shown to degrade leonardite, an oxidized form of lignite. An extracellular fraction containing protein purified from a C. versicolor culture solubilized leonardite in vitro. Expression of the activity did not require the presence of leonardite and appeared during idiophase. During ion-exchange and gel filtration column chromatography, leonardite-biosolubilizing activity eluted with syringaldazine oxidase activity and with protein, as measured by A(280) and the biuret protein assay. Syringaldazine is a substrate of the polyphenol oxidase formed by C. versicolor. Comparison of leonardite-biosolubilizing activity with the effects of chelators and surface-active agents on leonardite showed that biosolubilization was not due to either surfactant or chelating ability. Heat treatment of the preparation at 60 degrees C for 30 min significantly reduced both syringaldazine oxidase and leonardite-biosolubilizing activities. Cyanide, azide, and thioglycolate, which are known inhibitors of syringaldazine oxidase activity of C. versicolor, also inhibited leonardite biosolubilization. From these data, we conclude that the purified protein fraction from C. versicolor contains a syringaldazine oxidase activity that participates in leonardite biosolubilization by enzymatic action.
Department of Chemistry, Imperial College of Science and Technology, University of London, U.K.
Abstract
The electron paramagnetic resonance (EPR) spectra of type 1 copper(II) in 63Cu-enriched Coriolus versicolor laccase A (benzenediol:oxygen oxidoreductase, EC 1.10.3.2) have been studied. The X-band EPR spectrum in type 2 copper-depleted [63Cu]laccase A exhibited well-resolved ligand superhyperfine structure in the g perpendicular region. This structure was assigned to an interaction with two nitrogens and two protons, an assignment which is consistent with a model in which the two nitrogens belong to two histidine ligands and the two protons are the methylene protons of a coordinating cysteine. It also requires the delocalization of a substantial amount of the type 1 copper(II) unpaired electron density onto the cysteine sulphur.
Department of Bacteriology, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
Abstract
The effects of PSK and Propionibacterium acnes (anaerobic Corynebacterium) on hepatic drug-metabolizing enzymes were studied using sarcoma-180 bearing and non-tumor bearing mice. PSK had no influence on aminopyrine N-demethylase and aniline hydroxylase activities, cytochrome P-450 concentration in hepatic microsomes, and the reductase activity of cytochrome c in normal mice. The content of cytochrome P-450 was not significantly reduced in S-180 bearing mice. On the other hand, P. acnes administration significantly decreased the amount of cytochromes P-450 and b5 and aminopyrine N-demethylase activity. When FT-207 (Tegafur) was administered orally to S-180 bearing mice combined with the immunoadjuvants, only P. acnes significantly reduced the 5-FU levels in the serum and some organs.
Research Section of Lignin Chemistry, Wood Research Institute, Kyoto University, Japan.
Abstract
Phenolic beta-1 lignin substructure model compounds, 1-(3,5-dimethoxy-4-hydroxy-phenyl)-2-(3,5-dimethoxy-4-ethoxyphenyl)propa ne-1, 3-diol (I) and 1-(3,5-dimethoxy-4-ethoxyphenyl)-2-(3, 5-dimethoxy-4-hydroxyphenyl)propane-1,3-diol (II) were degraded by laccase of Coriolus versicolor. Substrate I was converted to 1-(3,5-dimethoxy-4-hydroxyphenyl)-2-(3,5-dimethoxy-4-ethoxyphenyl)-3- hydroxypropanone (III), 1-(3,5-dimethoxy-4-ethoxyphenyl)-2-hydroxyethanone (IV), syringaldehyde (V), 1-(3,5-dimethoxy-4-ethoxyphenyl)-3-hydroxypropanal (VI), 2,6-dimethoxy-p-hydroquinone (VII), and 2,6-dimethoxy-p-benzoquinone (VIII). Furthermore, incorporations of 18O of 18O2 into ethanone (IV) and 18O of H218O into hydroquinone (VII) and benzoquinone (VIII) were confirmed. Substrate II gave 1-(3,5-dimethoxy-4-hydroxyphenyl)ethane-1, 2-diol (IX), 1-(3,5-dimethoxy-4-hydroxyphenyl)-2-hydroxyethanone (X), and 3,5-dimethoxy-4-ethoxybenzaldehyde (XI). Also 18O of H218O was incorporated into glycol (IX) and ethanone (X). Based on the structures of the degradation products and the isotopic experiments, it was established that three types of reactions occurred via phenoxy radicals of substrates caused by laccase: (i) C alpha-C beta cleavage (between C1 and C2 carbons); (ii) alkyl-aryl cleavage (between C1 carbon and aryl group); and (iii) C alpha (C1) oxidation.
Research Section of Lignin Chemistry, Wood Research Institute, Kyoto University, Japan.
Abstract
It was found that 2,4-di(tert-butyl)-4-(methoxycarbonylmethyl)-2-buten-4-ol ide (II) was formed as an aromatic ring cleavage product of a phenolic lignin model compound, 4,6-di(tert-butyl)guaiacol (I), by laccase of Coriolus versicolor. Based on isotopic experiments with 18O2 and H2 18O, the mechanism of formation of II from I is discussed.
Department of Pathology, SUNY Health Science Center, Brooklyn 11203.
Abstract
A glycan extracted from Coriolus versicolor (PSK, Krestin) which has antitumor and immunomodulator properties produced marked morphological and biochemical changes when added to cultures of mouse peritoneal macrophages. The cells were more spread and elongated than in control cultures, and these changes were accompanied by alterations in the rate of protein and DNA synthesis. In PSK-treated murine peritoneal macrophages the rate of protein synthesis increased above the level seen in control cultures after two days and reached a level twenty-fold higher than control on day four; this elevated rate of protein synthesis was maintained throughout the seven-day observation period. DNA synthesis was induced after four days in the presence of PSK, and reached a level ten-fold higher than control baseline on day five. This induction of DNA synthesis, however, could not be attributed to a mitogenic activity on lymphocytes. The alterations caused by PSK in macrophage metabolism may be related to the immunomodulating and antitumor activities of PSK in vivo.
Using in vitro clonal culture assays, we investigated the effects of PSK, a protein-bound polysaccharide derived from the cultured mycelium of CM101, Coriolus versicolor (Fr.) Quél in Basidiomycetes, on human hemopoietic progenitors. PSK alone did not stimulate colony formation by human bone marrow progenitors. Although 1-100 micrograms/ml of PSK had no effects on colony formation stimulated by erythropoietin and medium conditioned by phytohemagglutinin-stimulated leukocytes, more than 1 mg/ml of PSK inhibited all types of colony formation. In contrast, medium conditioned by PSK-stimulated leukocytes significantly stimulated formation of various types of colonies including erythroid bursts, granulocyte and/or macrophage colonies, eosinophil colonies, megakaryocyte colonies and mixed hemopoietic colonies. It is speculated that administration of the optimal dose of PSK can reduce the hematological suppression of antitumor drugs.
Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108; Repligen-Sandoz Research Corp., Lexington, Massachusetts 02173 ; and Northern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois 61604.
Abstract
The white rot fungi used in this study caused two different forms of degradation. Phanerochaete chrysosporium, strain BKM-F-1767, and Phellinus pini caused a preferential removal of lignin from birch wood, whereas Trametes (Coriolus) versicolor caused a nonselective attack of all cell wall components. Use of polyclonal antisera to H8 lignin peroxidase and monoclonal antisera to H2 lignin peroxidase followed by immunogold labeling with protein A-gold or protein G-gold, respectively, showed lignin peroxidase extra-and intracellularly to fungal hyphae and within the delignified cell walls after 12 weeks of laboratory decay. Lignin peroxidase was localized at sites within the cell wall where electron-dense areas of the lignified cell wall layers remained. In wood decayed by Trametes versicolor, lignin peroxidase was located primarily along the surface of eroded cell walls. No lignin peroxidase was evident in brown-rotted wood, but slight labeling occurred within hyphal cells. Use of polyclonal antisera to xylanase followed by immunogold labeling showed intense labeling on fungal hyphae and surrounding slime layers and within the woody cell wall, where evidence of degradation was apparent. Colloidal-gold-labeled xylanase was prevalent in wood decayed by all fungi used in this study. Areas of the wood with early stages of cell wall decay had the greatest concentration of gold particles, while little labeling occurred in cells in advanced stages of decay by brown or white rot fungi.
First Department of Biochemistry, School of Medicine, Showa University, Tokyo, Japan.
Abstract
PSK, a protein-bound polysaccharide extracted from the mycelia of Coriolus versicolor (Fr.) Quel, stimulated tumor necrosis factor-induced cytotoxicity against mouse L-929 fibroblast. PSK also stimulated interferon-gamma-induced differentiation of human myelogenous leukemic U-937 and THP-1 cells. The differentiated cells had higher proportions of cells that expressed NBT-reducing activity and alpha-naphthyl acetate esterase activity. Among four PSK subfractions, the highest molecular weight fraction (MW greater than 200 kD) had the most potent stimulating activity. This is the first report regarding direct PSK modulation of cytokine action.