Antitumor and antiviral substances from fungi

Anticancer and Antioxidant Activities in Ganoderma lucidum Wild Mushrooms in Poland, as Well as Their Phenolic and Triterpenoid Compounds

The goal of this study was to the assess anti-cancer and antioxidant properties of the Ganoderma lucidum fruiting body, and to identify bioactive compounds found in their extracts. Significant antiproliferative activity was observed against MCF-7, MCF-7/DX, LOVO, LOVO/DX, MDA-MB 231, SW 620, and NHDF cell lines. With IC₅₀ values of 25.38 µg/mL and 47.90 µg/mL, respectively, the extract was most effective against MDA-MB 231 and SW 620 cell lines. The bioactive compounds were identified using an ACQUITY UPLC-PDA-MS system. The extracts contained 13 triterpenoids and 28 polyphenols from the flavonols, phenolic acids, flavones, flavan-3-ols, and stilbenes families. Ganoderic acid derivative was found to be the most abundant triterpenoid (162.4 mg/g DW), followed by ganoderic acid B (145.6 mg/g DW). Resveratrol was the most abundant phenolic in the extract (5155.7 mg/100 g DM). The findings could explain why G. lucidum extracts are used in folk medicine.

Submerged Cultivation of Inonotus obliquus Mycelium Using Statistical Design of Experiments and Mathematical Modeling to Increase Biomass Yield

Submerged culturing of mycelium is an efficient technique used to increase biomass yields, more so when employed with naturally slow-growing species of mushrooms. This paper is concerned with optimizing nutrient broth components used in Inonotus obliquus cultures for achieving high biomass yields. We modeled the effect of seven biotechnological parameters (six broth ingredients and the initial pH of nutritive broth) on mycelial biomass and predicted an optimum broth formula using response surface methodology. An analysis of variance showed that the elaborated model is significant (F-value of 2.76 and p-value of 0.0316). We used bioreactor cultures to confirm the model’s optimum prediction and to compare these results with a general-purpose mycology medium, namely potato dextrose broth (PDB). The optimized bioreactor culture yielded 4.37 g/L (93.36% of the dry weight prediction), while the PDB bioreactor culture yielded 2.084 g/L, after 15 days of cultivation. The optimized formula was: 2.15299 g malt extract, 3.99296 g yeast extract, 11.0041 g fructose, 17.4 g soluble starch, 0.1 g MgSO4, and 0.05 g CaCl2 per liter of broth.

Identification of Biologically Active Ganoderma lucidum Compounds and Synthesis of Improved Derivatives That Confer Anti-cancer Activities in vitro

We previously reported that Ganoderma lucidum extract (GLE) demonstrate significant anti-cancer activity against triple negative inflammatory breast cancer models. Herein, we aimed to elucidate the bioactive compounds of GLE responsible for this anti-cancer activity. We performed NMR, X-ray crystallography and analog derivatization as well as anti-cancer activity studies to elucidate and test the compounds. We report the structures of the seven most abundant GLE compounds and their selective efficacy against triple negative (TNBC) and inflammatory breast cancers (IBC) and other human cancer cell types (solid and blood malignancies) to illustrate their potential as anti-cancer agents. Three of the seven compounds (ergosterol, 5,6-dehydroergosterol and ergosterol peroxide) exhibited significant in vitro anti-cancer activities, while we report for the first time the structure elucidation of 5,6-dehydroergosterol from Ganoderma lucidum. We also show for the first time in TNBC/IBC cells that ergosterol peroxide (EP) displays anti-proliferative effects through G1 phase cell cycle arrest, apoptosis induction via caspase 3/7 activation, and PARP cleavage. EP decreased migratory and invasive effects of cancer cells while inhibiting the expression of total AKT1, AKT2, BCL-XL, Cyclin D1 and c-Myc in the tested IBC cells. Our investigation also indicates that these compounds induce reactive oxygen species, compromising cell fate. Furthermore, we generated a superior derivative, ergosterol peroxide sulfonamide, with improved potency in IBC cells and ample therapeutic index (TI > 10) compared to normal cells. The combined studies indicate that EP from Ganoderma lucidum extract is a promising molecular scaffold for further exploration as an anti-cancer agent.

Microbial production of scleroglucan and downstream processing

Synthetic petroleum-based polymers and natural plant polymers have the disadvantage of restricted sources, in addition to the non-biodegradability of the former ones. In contrast, eco-sustainable microbial polysaccharides, of low-cost and standardized production, represent an alternative to address this situation. With a strong global market, they attracted worldwide attention because of their novel and unique physico-chemical properties as well as varied industrial applications, and many of them are promptly becoming economically competitive. Scleroglucan, a β-1,3-β-1,6-glucan secreted by Sclerotium fungi, exhibits high potential for commercialization and may show different branching frequency, side-chain length, and/or molecular weight depending on the producing strain or culture conditions. Water-solubility, viscosifying ability and wide stability over temperature, pH and salinity make scleroglucan useful for different biotechnological (enhanced oil recovery, food additives, drug delivery, cosmetic and pharmaceutical products, biocompatible materials, etc.), and biomedical (immunoceutical, antitumor, etc.) applications. It can be copiously produced at bioreactor scale under standardized conditions, where a high exopolysaccharide concentration normally governs the process optimization. Operative and nutritional conditions, as well as the incidence of scleroglucan downstream processing will be discussed in this chapter. The relevance of using standardized inocula from selected strains and experiences concerning the intricate scleroglucan scaling-up will be also herein outlined.

Evaluation of rheological properties and swelling behaviour of sonicated scleroglucan samples

Scleroglucan is a natural polysaccharide that has been proposed for various applications. However there is no investigation on its property variations when the molecular weight of this polymer is reduced. Scleroglucan was sonicated at two different polymer concentrations for different periods of time and the effect of sonication was investigated with respect to molecular weight variations and rheological properties. Molar mass, estimated by viscometric measurements, was drastically reduced already after a sonication for a few min. Sonicated samples were used for the preparation of gels in the presence of borate ions. The effect of borax on the new samples was investigated by recording the mechanical spectra and the flow curves. A comparison with the system prepared with the dialysed polymer was also carried out. The anisotropic elongation, observed with tablets of scleroglucan and borax, was remarkably reduced when the sonicated samples were used for the preparation of the gels.

A high-performance molluscicidal ingredient against Oncomelania hupensis produced by a rhizospheric strain from Phytolacca acinosa Roxb

Background:

Snail (Oncomelania hupensis) control is an important and effective preventive strategy in schistosomiasis control programs, and screening microbial molluscicidal agents is one of the most promising categories in biomolluscicides.

Objective:

To purify and identify the molluscicidal ingredient (MI) obtained from strain SL-30's exocellular broth.

Materials and Methods:

The active extracts extracted from SL-30's exocellular broth was purified on a silica gel column guided by molluscicidal activity assay against Oncomelania hupensis, then the MI was obtained. NMR spectroscopy and LC-MS/MS analysis was used to identify the molecular structure of the MI.

Results:

Molluscicidal activity bioassay showed that the MI exhibited significant molluscicidal activity with the LC₅₀ values of 0.101, 0.062, and 0.022 mg/L, respectively, in the case of exposure period of 24 h. From ¹H NMR, ¹³C NMR, ¹H-¹H COSY, and ¹H-¹³C HSQC spectra, partial important structure fragment was obtained, and the relative molecular weight of the MI showed 326 according to LC-MS analysis. Then, on these grounds, it was indicated that the molecular structure of the MI had a higher similarity to Gliotoxin with the molecular formula of C₁₃ H₁₄N₂O₄S₂. The quasi-molecular ion of m/z 325.45 was further analyzed by MS² as the parent ion, and two daughter ions obtained at m/z 295.11 [M-CH₂OH]- and m/z 261.08 [M-CH₂OH -2S]–

Conclusion:

The MI was finally confirmed as Gliotoxin.

Isolation and identification of C-19 fatty acids with anti-tumor activity from the spores of Ganoderma lucidum (reishi mushroom)

We previously showed that ethanolic extracts of spores of Ganoderma lucidum inhibit tumor cell proliferation and induce apoptosis of HL-60 cells. The active constituents appeared to be long-chain fatty acids, particularly carbon-19 (C-19) fatty acids which have not been reported in spores of Ganoderma lucidum. In the present study, two of these C-19 fatty acids which are key compounds in the activities, were identified as their 2-naphthyl ester derivatives after esterification of a mixture of fatty acids obtained from the spores. The active compounds were determines as nonadecanoic acid and cis-9-nonadecenoic acid. The location of the double bond of cis-9-nonadecenoic acid was demonstrated by GC-MS analysis, based on the fragmentation pattern of the adduct prepared from the fatty acid and dimethyl disulfide.

Carboxymethyl derivative of scleroglucan: a novel thermosensitive hydrogel forming polysaccharide for drug delivery applications

A carboxymethyl derivative of scleroglucan (Scl-CM) with a derivatization degree of 65 +/- 5% was synthesized. The rheological behaviour of this novel polymer was studied and compared with that of the starting polymer. We observed that the charged moieties carried on the chains could prevent the triple helix formation of Scl. Scl-CM aqueous solutions behave like true polymer solutions up to 1% w/v, whereas above this concentration a weak gel behaviour was observed. CaCl(2) addition to aqueous Scl-CM solutions led to a physical gel formation; the hydrogel strength was related to polymer and CaCl(2) concentrations. Temperature sweeps, registered at 1 Hz on hydrogels differing in CaCl(2) concentration, evidenced a gel --> sol transition in the range of 30-40 degrees C, depending on the molar ratio between carboxylic groups and Ca(+2). In order to verify a possible use of these hydrogels as drug delivery systems, acyclovir was loaded into the network. Rheological analysis evidenced that the loaded drug can affect the hydrogel elastic modulus. The release of acyclovir in phosphate buffer was evaluated at different temperatures in order to assess the suitability of this novel drug delivery system in topical applications.

Anti-tumor and immunomodulating activities of proteoglycans from mycelium of Phellinus nigricans and culture medium

Two proteoglycans, PNW1 and PNM1, were isolated from the mycelium of Phellinus nigricans through submerged fermentation and culture medium, respectively. PNW1 and PNM1 with similar average molecular weight (33 kDa and 29 kDa) were composed of glucose, galactose, mannose, arabinose and fucose in the molar ratios of 3.26:8.77:6.44:1:1.35 and 20.06:8.72:6.94:1:0.76. At the dose of 100, 200, and 400 mg/kg, PNW1 and PNM1 exhibited anti-tumor activity against mice-transplanted Sarcoma 180 in vivo. However, no direct cytotoxic activity against Sarcoma 180 could be determined. Significant increase in the relative spleen and thymus weight and expression of tumor necrosis factor-alpha (TNF-alpha) in serum was observed, decreasing the tumor weight significantly. PNW1 and PNM1 could stimulate lymphocytes proliferation and increase production of nitric oxide (NO) and TNF-alpha in macrophages. The results indicate that both lymphocyte and macrophages were activated by preparations of proteoglycans from mycelium and culture medium of P. nigricans. The anti-tumor effect of the proteoglycans is not directly tumoricidal but rather immunostimulating.

Fungal substances as modulators of NF-κB activation pathway

MCF7 breast cancer cell line, carrying a luciferase reporter gene under the control of nuclear factor kappa B (NF-kappaB)-responsive promoter, was established and used for the screening of fungal organic extracts for their ability to interfere with the NF-kappaB activation pathway. Twenty-eight crude fungal extracts, out of 242, were found to inhibit NF-kappaB reporter activity by more than 40%. Furthermore, positive extracts were used to evaluate their antiproliferative activity as well as their ability to influence the phosphorylation and degradation levels of IkappaBa. Fungal extracts prepared from Marasmius oreades and Cyathus striatus showed significant inhibitory effects on the NF-kappaB activation pathway. Taken together, our results support the notion of the presence of novel activities that might be utilized as cancer therapeutics.

An Extract of the Medicinal Mushroom Agaricus blazei Murill Differentially Stimulates Production of Pro-inflammatory Cytokines in Human Monocytes and Human Vein Endothelial Cells in vitro

An extract of the edible mushroom Agaricus blazei Murill (AbM) has known antitumor and anti-infection properties, probably mainly by stimulating mononuclear phagocytes of the native immune system. The aim of this work was to study the effect of AbM on the production by human monocytes and human umbilical vein endothelial cells (EC) of pro-inflammatory cytokines (IL-1beta, IL-6, IL-8, TNFalpha), the anti-inflammatory/T regulatory cytokine IL-10 and the pro-Th1 cytokine IL-12. AbM, in concentrations from 1-15%, induced a considerable and dose-dependent increase in production of IL-8, IL-6, TNFalpha and IL-1beta in monocyte cultures. The biosynthesis reached a plateau at a concentration of 10% of AbM, and was most pronounced for the three former cytokines. AbM did also dose-dependently stimulate EC production of IL-8,I L-6 and TNFalpha, but at lower levels compared with the monocytes. AbM did neither induce synthesis of cytokines IL-10 nor IL-12 in monocytes or EC. Our results demonstrate the differential effect of AbM stimulation on the magnitude of pro-inflammatory cytokines produced by monocytes and EC.

In Vivo Antitumor Activity of Clitocine, an Exocyclic Amino Nucleoside Isolated fromLepista inversa

A biologically guided fractionation from Lepista inversa (Scop.: Fr.) led to the isolation of clitocine, an exocyclic amino nucleoside. This compound and two mixtures of beta/alpha anomers (mixture A, 40:60 and mixture B, 80:20) were synthesized or isolated depending on the purification procedure. The beta anomer and clitocine mixtures A and B showed similar cytotoxic activities with IC50 values ranging from 20.5 to 42 nM in murine cancer cell lines (3LL and L1210) and from 185 to 578 nM in human cancer cell lines (DU145, K-562, MCF7, and U251). An in vivo study of mixture B was carried out on 3LL- and L1210-tumor-bearing mice. Clitocine solubilized in beta-hydroxypropylcyclodextrin and injected at concentrations of 0.5, 3, and 5 mg kg-1 did not significantly increase the survival rate and lifespan of 3LL-tumor-bearing mice. In contrast, clitocine showed antitumor activity on L1210-tumor-bearing mice with a significant increase in lifespan and a decrease in the development of ascites observed at 3 mg kg-1. The induction of apoptosis may be the basis of the antitumor activity of clitocine against L1210 as suggested by flow-cytometry analysis of cells treated in vitro.

Effect of 26-oxygenosterols from Ganoderma lucidum and their activity as cholesterol synthesis inhibitors

Ganoderma lucidum is a medicinal fungus belonging to the Polyporaceae family which has long been known in Japan as Reishi and has been used extensively in traditional Chinese medicine. We report the isolation and identification of the 26-oxygenosterols ganoderol A, ganoderol B, ganoderal A, and ganoderic acid Y and their biological effects on cholesterol synthesis in a human hepatic cell line in vitro. We also investigated the site of inhibition in the cholesterol synthesis pathway. We found that these oxygenated sterols from G. lucidum inhibited cholesterol biosynthesis via conversion of acetate or mevalonate as a precursor of cholesterol. By incorporation of 24,25-dihydro-[24,25-3H2]lanosterol and [3-3H]lathosterol in the presence of ganoderol A, we determined that the point of inhibition of cholesterol synthesis is between lanosterol and lathosterol. These results demonstrate that the lanosterol 14alpha-demethylase, which converts 24,25-dihydrolanosterol to cholesterol, can be inhibited by the 26-oxygenosterols from G. lucidum. These 26-oxygenosterols could lead to novel therapeutic agents that lower blood cholesterol.

Morphologies and conformation transition of lentinan in aqueous NaOH solution

Molecular morphologies and conformation transition of lentinan, a beta-(1-->3)-D-glucan from Lentinus edodes, were studied in aqueous NaOH solution by atomic force microscopy (AFM), viscometry, multiangle laser light scattering, and optical rotation measurements. The results revealed that lentinan exists as triple-helical chains and as single random-coil chains at NaOH concentration lower than 0.05M and higher than 0.08M, respectively. Moreover, the dramatic changes in weight-average molecular weight Mw, radius of gyration [s2](1/2), intrinsic viscosity [eta], as well as specific optical rotation at 589 nm [alpha]589 occurred in a narrow range of NaOH concentration between 0.05 and 0.08M NaOH, indicating that the helix-coil conformation transition of lentinan was carried out more easily than that of native schizophyllan and scleroglucan, and was irreversible. For the first time, we confirmed that the denatured lentinan molecule, which was dissolved in 0.15M NaOH to be disrupted into single coil chains, could be renatured as triple helical chain by dialyzing against abundant water in the regenerated cellulose tube at ambient temperature (15 degrees C). In view of the AFM image, lentinan in aqueous solution exhibited the linear, circular, and branched species of triple helix compared with native linear schizophyllan or scleroglucan.

Selective induction of apoptosis in murine skin carcinoma cells (CH72) by an ethanol extract of Lentinula edodes

The effects of ethanol extracts from four species of mushroom fruiting bodies, mushroom spores and mushroom cultured broth, were assessed for modulation of cell proliferation and apoptosis in murine skin carcinoma cells (CH72) and non-tumorigenic epidermal cells (C50). While extracts from mycelia of Grifola frondosa, Ganoderma lucidum, Hericium erinaceus, or from spores of G. lucidum exerted little, if any, effect on proliferation, the ethanol-soluble extract of Lentinula edodes (L. edodes) significantly decreased cell proliferation of CH72 cells. There were no changes in the proliferative response of the non-tumorigenic keratinocyte cell line, C50, to any of the mushroom extracts tested. To analyze cell proliferation and apoptosis, fluorescent DNA-microscopy with ethidium bromide and acridine orange staining of cells revealed L. edodes reduced cell proliferation and induced apoptosis in time- and dose-dependent manners in carcinoma cells but had no effect in non-tumorigenic cells (C50). Cell cycle analysis demonstrated that L. edodes extract induced a transient G(1) arrest, with no changes observed in the non-tumorigenic cells (C50).

Scleroglucan: a versatile polysaccharide for modified drug delivery

Scleroglucan is a natural polysaccharide, produced by fungi of the genus Sclerotium, that has been extensively studied for various commercial applications (secondary oil recovery, ceramic glazes, food, paints, etc.) and also shows several interesting pharmacological properties. This review focuses its attention on the use of scleroglucan, and some derivatives, in the field of pharmaceutics and in particular for the formulation of modified-release dosage forms. The reported investigations refer mainly to the following topics: natural scleroglucan suitable for the preparation of sustained release tablets and ocular formulations; oxidized and crosslinked scleroglucan used as a matrix for dosage forms sensitive to environmental conditions; co-crosslinked scleroglucan/gellan whose delivery rate can be affected by calcium ions. Furthermore, a novel hydrogel obtained with this polysaccharide and borate ions is described, and the particular structure of this hydrogel network has been interpreted in terms of conformational analysis and molecular dynamics. Profound attention is devoted to the mechanisms involved in drug release from the tested dosage forms that depend, according to the specific preparation, on swelling and/or diffusion. Experimental data are also discussed on the basis of a mathematical approach that allows a better understanding of the behavior of the tested polymeric materials.

Immunomodulating and anti-tumor action of extracts of several mushrooms

Aqueous extracts from fruit bodies and mycelia of various higher Basidiomycetes were studied in search for reliable biological effects. In vitro and in vivo experiments were conducted. The results showed that the aqueous extracts demonstrated various types of marked biological actions: an increased production of reactive oxygen forms by neutrophil cells of human peripheral blood; a significant mitogenic activity in a wide range of concentrations; stimulation on production of inflammatory cytokines interleukine 1-beta and interleukine-8 by peripheral blood cells; a decrease in both average tumor size in mice with transplanted melanoma B16 and a manifestation of tumorous intoxication; and a prolongation in the survival rate of such mice.

Rheological characterization of schizophyllan aqueous solutions after denaturation-renaturation treatment

Schizophyllan (SPG) with a molecular weight of 2.6x10(6), designated SPG-1, is denatured and then renatured at a concentration of 1.8 wt % by alkalization-neutralization. The prepared denatured-renatured samples (DRSPG-1) are diluted to various concentrations and equilibrated for 10 days before rheological and intrinsic viscosity measurements. When concentration (C(p)) is above 0.75 wt %, DRSPG-1 aqueous systems have weak gel-type rheological properties. However, for 0.28 wt % <or= C(p) <or= 0.65 wt % and C(p) <or= 0.19 wt %, DRSPG-1 aqueous systems behave as power law fluids and Newtonian fluids, respectively, which are attributed to the moderate isotropy degree of DRSPG-1 chains. Furthermore, a critical overlap parameter of c*[eta] = 1.2 is determined for DRSPG-1 in aqueous solutions, which is close to that of 1 for intact SPG in water while far smaller than that of 4.3 for SPG in DMSO. This is considered to be due to the strong interactions of DRSPG-1 chains in water, further confirmed by the intrinsic viscosity measurements in which the DRSPG-1 aqueous solution shows an abnormally large value of Huggins constant. Regarding the structure of DRSPG-1 weak gels, multiruns of dynamic strain sweep measurements suggest that the dominant structures are aggregates formed by hydrogen-bonding associations of DRSPG-1 chains rather than the permanent three-dimensional network. In addition, the step-shear rate tests are performed to study the thixotropic properties of DRSPG-1 aqueous systems.

Cytotoxic and antitumor activities of a polypore macrofungus, Phellinus rimosus (Berk) Pilat

Cytotoxic and antitumor activities of ethyl acetate, methanol and aqueous extracts of a wood inhabiting polypore macrofungus, Phellinus rimosus (Berk) Pilat. were studied. Ethyl acetate and methanol extracts showed in vitro cytotoxic activity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines. The aqueous extract did not exhibit cytotoxicity against the tested cell lines. All the three extracts were highly effective in inhibiting growth of solid tumor induced by DLA cell line in mice. However, the antitumor activity of ethyl acetate extract was higher than that of methanol and aqueous extracts. The ethyl acetate extract was also effective in preventing the EAC induced ascites tumor development in mice. The antitumor activity of all the three extracts against solid tumor at a dose of 50 mg/kg (p.o.) was comparable to the clinically used standard reference drug, cisplatin (4 mg/kg, i.p.). Pre-treatment of the extracts was also effective in inhibiting the tumor growth induced by DLA cell lines. The experimental results revealed that ethyl acetate extract of P. rimosus possessed significant antitumor activity. The findings thus suggest the potential use of this mushroom as antitumor agent.

Gelation behaviors of schizophyllan-sorbitol aqueous solutions

On addition of D-sorbitol, schizophyllan (SPG) aqueous solution forms a thermoreversible gel upon cooling. The gelation process is characterized by rheology, differential scanning calorimetry (DSC), and optical rotation measurement (ORD). It is found that the Winter-Chambon criterion works well in determining the critical gelation point of the present system, although the criterion has been scarcely applicable to systems that show weak-gel properties even before gelation. Moreover, ORD and DSC results indicate that a disordered to ordered conformational change accompanies the gelation process, which is attributed to the transition from SPG triple helix II to I. The gelation temperature of SPG-sorbitol aqueous solution is almost independent of SPG concentration in the examined concentration range and is slightly decreased by lowering SPG molecular weight, while greatly influenced by sorbitol content. The gelation is considered to be induced by the transition from SPG triple helix II to I, which leads to a three-dimensional network constituted by the extremely entangled and stiff SPG triple helices I. Furthermore, it is proved that neither junction zone nor aggregation of SPG triple helices is involved in the SPG-sorbitol gels. The SPG-sorbitol gel is structurally like a solution that is unable to flow within a timescale of usual observation.

Bioactive polysaccharides from traditional Chinese medicine herbs as anticancer adjuvants

PURPOSE OF STUDY

To review the nature, extent, bioactivities, and clinical application of polysaccharides in Traditional Chinese Medicine (TCM) especially as adjuvants in cancer treatment.

METHODOLOGY

Literature review.

FINDINGS

Many fungal- and plant-derived bioactive polysaccharides with a broad range of immunomodulatory activities are found in TCM. Some such polysaccharides have been developed into drugs and show clinical efficacy in controlled trials while the majority of such compounds remain as nutraceuticals with only preliminary research. Such polysaccharides are generally nontoxic and possess other bioactivities such as inducing differentiation, stimulating hematopoiesis, antimetastasis, and antiangiogenesis, which make them ideal adjuvants in modern cancer therapy.

CONCLUSION

Bioactive polysaccharides occur extensively in TCM herbs and are the basis of potentially useful application of TCM as an adjuvant in cancer therapies.

Tapping mode Atomic Force Microscopy of scleroglucan networks

Tapping mode Atomic Force Microscopy (TmAFM) has been used to study the fungal polysaccharide scleroglucan deposited from aqueous solution and dimethyl sulfoxide (DMSO) onto a mica surface. The solutions from which the microscope samples were produced were prepared by first dissolving the solid scleroglucan in 0.1M NaOH, then neutralizing the solution with HCl, followed by dilution to the required concentration in either water or DMSO. It was found that from the aqueous solution described above, scleroglucan forms networks. Based on a comparison of the denatured-renatured and aqueous solution samples, network formation is due to the imperfect registration between the chains forming the triple helices. The relatively large stiffness of the scleroglucan triple helix is also assumed to contribute to the formation of the extended networks. The triple helix diameter was measured to be 0.92 +/- 0.27 nm, which is in the same range as that obtained by other researchers using similar techniques. Denatured scleroglucan, deposited from DMSO onto mica, forms a web-like layer on top of which there are sphere-like structures. These morphologies are believed to be due to triple helix denaturation yielding highly flexible single chains in DMSO, which results in coiling and web-like dense packing of scleroglucan upon deposition onto mica. Most interestingly after additional of water to the samples deposited from DMSO, some of the chains can be renatured into short, stiff rod-like structures which are similar to the structures observed by others researchers. The imaging data for aqueous solution deposition can be analyzed by plotting maximum end-to-end distance versus the perimeter of the networks deposited onto mica. This yields a Flory-like exponent of 0.67, which is almost similar in value to that obtained by other researchers for linear structures of scleroglucan but less than that expected for a polymer chain following a self-avoiding walk (upsilon = 0.75) model on a two-dimensional surface. The fractal dimension that can be used to characterize the networks was determined graphically to be 1.22 +/- 0.06.

Isolation of ergosterol peroxide and its reversion to ergosterol in the pathogenic fungus Sporothrix schenckii

Ergosterol peroxide, a presumed product of the H2O2-dependent enzymatic oxidation of ergosterol, has been isolated from yeast forms of the pathogenic fungus Sporothrix schenckii. The substance, which may have a role in fungal virulence, has been characterized mainly using spectroscopic methods (1H and 13C nuclear magnetic resonance and high resolution mass spectra). The purified compound showed a molecular formula of C28H44O3, displaying characteristic features of epidioxy sterols and was reverted to ergosterol when submitted to S. schenckii enzymatic extract.

Polysaccharide-peptide complexes from the cultured mycelia of the mushroom Coriolus versicolor and their culture medium activate mouse lymphocytes and macrophages

The aim of this study was to investigate the effects of the mushroom Coriolus versicolor on cells of the immune system. The cultured mycelia of the mushroom Coriolus versicolor and their culture medium were separately extracted with boiling water. The resulting polysaccharopeptide preparations were designated intramycelial (IM) and extramycelial materials (EM), and were separated by gel filtration before determining their effects on lymphocytes and macrophages in vitro and in vivo. After gel filtration on Sepharose 6B, only a single peak with a molecular weight of 13-19 KDa was obtained. Gel filtration of IM and EM on Sephadex G-50 revealed the presence of a larger peak of 28 KDa (from IM) and 15 KDa (from EM) and a smaller peak of 3.5 KDa. IM, EM and their large molecular peaks enhanced the mitogenic response of T-cells from BALB/c mice in vitro. Splenocytes from C57BL/6 mice pre-treated by force-feeding with IM and EM demonstrated an augmented mitogenic response to Con A. The macrophages of C57BL/6 mice that had been pre-treated with IM or EM showed an enhanced production of nitrite ions. The results indicate that both mouse lymphocytes and macrophages were activated by preparations of polysaccharopeptide from cultured mycelia and culture medium of C. versicolor. However, no direct cytotoxic activity against fibroblasts, hepatoma cells and choriocarcinoma cells could be demonstrated.

In vitro antifungal activity of Polyporaceae against yeasts and dermatophytes

The antifungal activity of 38 Polyporaceae sensu lato against yeasts and dermatophytes was tested in vitro by the agar dilution method. Strains were typed organisms and clinical isolates. In this first report, Pycnoporellus fulgens (Fr.) Donk was found to be the most active species against pathological fungi and showed broad-spectrum antifungal activity against yeasts (Candida albicans, Candida glabrata) and dermatophytes (Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum). Other Polyporaceae species also showed antifungal activity, but only against dermatophytes.

Effects of Aspergillus terreus extract on herpes simplex 1 virus replication

In this study we reported about the antiviral activity of Aspergillus terreus alcohol extract against Herpes simplex type 1 virus. This activity is dose-dependent, is related to the concentration of the challenging virus and depends particularly on a proteic fraction of 5-10 Kda. Optimal effects were observed with doses ranging from 25 to 6.25 micrograms/ml for crude alcohol extract and up to 3 micrograms/ml for 5-10 Kda fraction. Moreover, antiviral activity was evident in viral replication, but not on virus out of the cells. An increased 3H thymidine incorporation was noted on infected cells treated with the extract and this effect may suggest an intracellular accumulation of viral DNA in the absence or reduction of virion production.

Physicochemical factors affecting the formation of the biological response modifier scleroglucan

The use of phosphate as the limiting nutrient for scleroglucan formation by Sclerotium glucanicum led to stimulation of glucan formation. Final exopolysaccharide concentrations achieved in phosphate-limited (18.9 kg m-3) cultures were much higher than in the usual nitrogen-limited fermentations (11.4 kg m-3). The mechanism by which phosphate limitation engendered glucan formation may be largely non-specific, involving a generalised diversion of the carbon source away from biomass formation and towards glucan synthesis. The effect of stirrer speed was examined in a fermenter fitted with a 6-bladed Rushton turbine impeller of 0.5 vessel diameter. It was noted that biomass and scleroglucan formation showed different optima. This may have been due to the markedly different oxygen requirements of the two processes.

Activation of peritoneal macrophages by polysaccharopeptide from the mushroom, Coriolus versicolor

Polysaccharopeptide (PSP) is a substance produced by an edible mushroom, Coriolus versicolor which has been claimed to possess antitumor activity. However, neither tumoricidal activity nor cytotoxicity was observed when five tumor cell lines and mouse peritoneal macrophages were cultured in vitro in the presence of 2.5-10 micrograms/ml PSP. An increase in the production of reactive nitrogen intermediates, reactive oxygen intermediates (superoxide anions) and tumor necrosis factor was measured in peritoneal macrophages collected from inbred C57 mice which had received PSP in the drinking water for 2 weeks. Northern blot analysis also demonstrated that PSP activated the transcription of tumor necrosis factor gene in these cells, indicating that PSP exerted an immunomodulatory effect on the defensive cells.