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November 2010

Competitive action of a biological response modifier, PSK, on a humoral immunosuppressive factor produced in tumor-bearing hosts.

We investigated the effect of PSK, a protein-bound polysaccharide obtained from the basidiomycetes Coriolus versicolor, on an immunosuppressive factor produced in tumor-bearing animals. Oral administration of PSK suppressed the growth of the tumor in C3H/He mice bearing X5563 plasmacytoma or MH134 hepatoma, but affected mice bearing MM102 mammary tumor little. PSK prevented the reduction in splenic lymphocyte blastogenesis caused by phytohemagglutinin that occurs in mice bearing X5563 tumors or MH134 hepatoma. The lymphocyte blastogenesis affected little by tumor or PSK in mice bearing MM102 tumors. The effect of sera on the blastogenesis of lymphocytes caused by phytohemagglutinin was different with different tumors in the C3H/He mice. Serum of mice bearing X5563 tumors inhibited blastogenesis, but serum of mice bearing MH134 hepatoma or MM102 tumors promoted it. The sera of mice bearing MH134 hepatoma contained both inhibitory and promotive factors; those of mice bearing X5563 tumors contained an inhibitory factor, and those of mice bearing MM102 tumors contained a promotive factor. The oral administration of PSK reduced the inhibition caused by the sera of mice bearing X5563 tumors. The promotive activity of sera from mice bearing MH134 hepatoma was augmented by PSK; that of sera in mice bearing MM102 tumors was not affected by PSK. Living Bacillus Calmette-Guérin did not have such effects in any of these mice. Serum immunosuppressive activity was also reduced by PSK in various tumor lines of rodents. These results suggest that PSK acts by reducing the activity of immunosuppressive factors produced in tumor-bearing hosts.[…]

Characterization of lignin peroxidase-encoding genes from lignin-degrading basidiomycetes.

Two closely linked lignin peroxidase (LPO)-encoding genes (lpo) from Phanerochaete chrysosporium were isolated. Nucleotide sequence studies indicated that the two genes are separated by 1.3 kb of flanking DNA and transcribed in opposite directions. Cloned P. chrysosporium lpo gene probes have been shown to hybridize to multiple sequences present in the DNAs of the white-rot fungi, Bjerkandera adusta, Coriolus versicolor and Fomes lignosus, but no hybridization was detected with DNA from Pleurotus ostreatus. Thus, lpo gene families appear to be common in a number of lignin-degrading basidiomycetes, some of which have not yet been shown to produce LPO proteins.[…]

Stimulation of human peripheral blood polymorphonuclear cell iodination by PSK subfractions.

A protein-bound polysaccharide, PSK, extracted from the mycelium of Coriolus versicolor (Fr.) Quel, stimulated the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN), human promyelocytic leukemic HL-60 cells and human myeloblastic leukemic ML-1 cells. In contrast, PSK did not significantly increase the iodination of other cultured cell lines (U-937, THP-1, L-929, T98G, BALB 3T3). The PSK stimulation of iodination of both PMN and HL-60 cells depended on incubation time and temperature, and was significantly suppressed by the presence of myeloperoxidase inhibitors. Among various PSK subfractions, the highest molecular weight fraction (MW greater than 200 kD), or the fraction precipitated at pH 4.0-4.5, stimulated the iodination most. In contrast, natural and chemically modified glucans had little or no stimulation activity. The active PSK subfractions synergistically enhanced TNF stimulation of PMN iodination. The data suggest the presence of some unique components in PSK which directly stimulate the iodination of myeloperoxidase-positive cells.[…]

Nucleases in the autolysis of filamentous fungi.

RNase and DNase activities were studied in seven fungi of the subdivisions Ascomycotina, Zygomycotina and Basidiomycotina during their autolysis, and extracellular and intracellular RNase and DNase were found. RNase specific activity reached higher levels than DNase specific activity in the culture liquid and mycelial extract, except in Aspergillus nidulans. Generally maximal RNase specific activities were observed at the onset of autolysis in the culture liquid. In the mycelial extract an increase in this activity with the incubation time was observed, except in A. nidulans and Coriolus versicolor. The highest values of DNase specific activities were found at the third day of autolysis in A. nidulans culture liquid and at the thirtieth day of autolysis in Schizophyllum commune mycelial extract. A possible relationship between the culture liquid pH during the autolysis of the studied fungi and the levels of DNase specific activity was observed.[…]

Oxidation of non-phenolic substrates. An expanded role for laccase in lignin biodegradation.

In the presence of substrates such as Remazol Blue and 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate) (ABTS), laccases Coriolus (Trametes) versicolor can also oxidize non-phenolic lignin model compounds. Veratryl alcohol (I) and 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-propane-1,3-diol (III) were oxidized by laccase and mediator to give the alpha-carbonyl derivatives. The beta-1 lignin model dimer, 1-(3,4-dimethoxyphenyl)-2-phenoxy-ethane-1,2-diol (II) was cleaved by laccase in the presence of ABTS to give veratraldehyde and benzaldehyde. On the basis of these observations, we propose that laccase is capable of oxidizing both phenolic and non-phenolic moieties of lignin but that the latter is dependent on the co-presence of primary laccase substrates.[…]

Cell surface changes of in situ macrophages induced by superimposed antigen.

Mice received an injection of sheep erythrocytes (SRBC) into the footpad ” prepared” or “not prepared” with a 7-day-prior injection of a protein-bound polysaccharide from Coriolus versicolor (PSK; Krestin), and the ultrastructure of in situ macrophages was studied at various intervals after the injection. A single SRBC injection into the footpad induced linear cell arrangements of several macrophages. The macrophages showed no prominent morphological alterations after SRBC digestion. When PSK-stimulated subcutaneous macrophages were challenged by SRBC, they rapidly sent out numerous long cytoplasmic projections which radiated in all directions. Such projections of neighboring macrophages tended to contact one another. At the following stage, a pronounced sequential alteration was noted, characterized by the interlocking of elongated projections. This provided massive aggregations of “activated” macrophages. These observations suggest the possibility that intercellular communication among “activated” macrophages was elicited, particularly in the subcutaneous region, and maintained through an intensive interaction of cytoplasmic projections. Further, the present results histologically support our previous report which shows that the “PSK-prepared” footpad site but not the “prepared” one supports development of a splenic humoral immune response following injection of superimposed SRBC.[…]

Effects of a protein-bound polysaccharide from a basidiomycetes against hepatocarcinogenesis induced by 3′-methyl-4-dimethylaminoazobenzene in rats.

PSK, extracted from mycelia of a strain of Coriolus versicolor, was administered to groups of 20 male Wistar rats before and during treatment with 3′-methyl-4-dimethylaminoazobenzene (3-MDAB). After 24 weeks, the survival rates were significantly higher in the groups given PSK before or with the 3-MDAB than in groups not given PSK or given PSK after 12 weeks of 3-MDAB treatment. Blood alpha-fetoprotein levels, determined every four weeks, increased in all groups after 3-MDAB treatment, but were significantly lower in the groups given PSK before or with the 3-MDAB than in the other groups. The results indicate that PSK had a suppressive effect on 3-MDAB-induced hepatocarcinogenesis.[…]

Immune enhancement of a polysaccharides peptides isolated from Coriolus versicolor.

A protein-bound polysaccharides (PSP) isolated from Coriolus versicolor in Shanghai, at the concentrations of 100-800 micrograms/ml promoted lymphocyte proliferation. PSP 25 mg/kg ip into mice for 5 d antagonized the inhibition of IL-2 production by cyclophosphamide from activated T lymphocytes and restored the suppressed T-cell-mediated delayed, type hypersensitivity response to normal. PSP 10-1000 micrograms/ml induced interferon alpha and gamma production from human peripheral leukocytes 4 and 8 times respectively higher than that of the control groups. Moreover, PSP also increased phagocytic functions of host reticulo-endothelial system. The results suggest that the anti-tumor effects of PSP may be related to its potentiation of host immunological responses.[…]

Chloromethane, Methyl Donor in Veratryl Alcohol Biosynthesis in Phanerochaete chrysosporium and Other Lignin-Degrading Fungi.

Chloromethane, a gaseous natural product implicated in methylation processes in Phellinus pomaceus, has been shown to act as methyl donor in veratryl alcohol biosynthesis in the lignin-degrading fungi Phanerochaete chrysosporium, Phlebia radiata, and Coriolus versicolor, none of which released detectable amounts of CH(3)Cl during growth. When P. chrysosporium was grown in a medium containing CH(3)Cl, levels of CH(3) incorporation into the 3- and 4-O-methyl groups of veratryl alcohol were very high and initially similar to those observed when the medium was supplemented with l-[methyl-H(3)]methionine. When CH(3)Cl was added to cultures actively synthesizing veratryl alcohol, incorporation of CH(3) was very rapid, with 81% of veratryl alcohol labeled after 12 h. By contrast, incorporation of CH(3) from l-[methyl-H(3)]methionine was comparatively slow, attaining 10% after 12 h. It is proposed that these lignin-degrading fungi possess a tightly channeled multienzyme system in which CH(3)Cl biosynthesis is closely coupled to CH(3)Cl utilization for methylation of veratryl alcohol precursors.[…]

Optimization of cultivation and nutrition conditions and substrate pretreatment for solid-substrate fermentation of wheat straw by Coriolus versicolor.

Bioconversion of wheat straw by solid-substrate fermentation (SSF) with Coriolus versicolor was optimized by varying its physiological parameters. Selective delignification (more lignin than holocellulose degradation) and increases in crude protein (CP) content and in vitro dry matter digestibility (IVDMD) were taken as the criteria to select optimum levels of these parameters. The fungus behaved optimally under the following set of cultural and nutritional conditions: pH 5.5, moisture level 55%, temperature 30 degrees C, duration of fermentation 21 d, form of inoculum–grain culture, turning frequency–once at mid-incubation, urea (nitrogen source) 1.5% (sterile) or 3.0% (nonsterile), single superphosphate (phosphorus + sulfur source) 1.0%, no addition of free polysaccharides (as whey or molasses). A maximum of 17.5% increase in IVDMD involving 4.3% degradation of lignin, was attained in the optimized SSF under laboratory conditions. The digestibility improvement could be further increased by using a substrate pretreatment (physical/chemical/biological) in the following order of preference: NaOH treatment, urea or urine treatment, ensiling, steaming, grinding. For practical farm applications, urea treatment and ensiling appeared most feasible. The laboratory optimized process was also scaled up to 4 kg (sterile and unsterile) and 50 kg (unsterile) fermentations[…]