Intravenously administered (1----3)-beta-D-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 augments murine peritoneal macrophage functions in vivo.

Effect of intravenously (i.v.) or intraperitoneally (i.p.) administered (1----3)-beta-D-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 on the murine peritoneal macrophage (PM) functions were examined. A single i.v. administration of SSG increased the number of PMs at a dose of 250 micrograms/mouse, and the peak appeared 4 d after administration. However, no special change was observed on peritoneal exude cell (PEC) populations. These PMs showed augmented lysosomal enzyme activity and the peaks appeared in 2 phases, on days 2 and 10. In contrast, SSG administered i.p. (250 micrograms/mouse) increased the number of PMs and enhanced the lysosomal enzyme activity of PMs from day 4, and a broad peak appeared until days 8--12. The populations of PECs were also changed by i.p. injection of SSG. Additionally, SSG administered i.v. enhanced phagocytic activity, H2O2 production and interleukin 1 (IL-1) production, and the kinetics of the activation differed depending on the activities. These data suggest that the effects of SSG on macrophage functions are different depending on administration routes, and there are some different mechanisms in the activation of macrophages in vivo by SSG.     

Heat induced generation of the mitogenic substance(s) responding to murine splenocytes obtained from sclerotia of Sclerotinia sclerotiorum IFO 9395

We have demonstrated that hot water extracts of sclerotia of Sclerotinia sclerotiorum IFO 9395 (TSHW) show various immunomodulating activities and mitogenic substance(s) were recovered from the beta-1,3-glucanase resistant-fraction (EDP) (Shinohara et al. Chem. Pharm. Bull., 37, 2174 (1989]. In this paper, we examined whether or not the mitogenic substance(s) were also obtained from the other methods, phosphate buffer extraction. Although the native extracts (3S-M) sterilized with a membrane filter showed a slight mitogenicity to murine splenocytes, 3S-M denatured in boiling water (3S-MB) showed significant activity. Treatment of 3S-M for only 1 min in boiling water or 10 min at 70 degrees C was sufficient to show significant mitogenic activity. After heat treatment of 3S-M in boiling water for 30 s, the main band corresponding to that of 3S-M was not clearly observed. Instead, new bands appeared at the top of the gel in normal-polyacrylamide gel electrophoresis (normal-PAGE), suggesting that many physicochemical changes occurred during the heat treatment. These findings suggest that heat denaturation of the substance(s) from sclerotia was one of the triggering mechanisms expressing mitogenic activity to murine splenocytes.     

Preparation and antitumor activity of hydroxyethylated derivatives of 6-branched (1----3)-beta-D-glucan, SSG, obtained from the culture filtrate of Sclerotinia sclerotiorum IFO 9395

SSG is an antitumor branched (1----3)-beta-D-glucan obtained from the culture filtrate of Sclerotinia sclerotiorum IFO 9395. Hydroxyethylation of SSG higher than MS 0.45 (MS value represents molar ratio of hydroxyethyl group vs. glucosyl group) by ethyleneoxide in aqueous sodium hydroxide lose the antitumor activity. Degradation of branching point of hydroxyethylated SSG (HE-SSG) by the sequential treatments of periodate oxidation, borohydride reduction, and mild acid hydrolysis of these derivatives regenerated the antitumor activity. These results directly demonstrated that the branching point covered, at least a part of, the dormant active site of SSG.     

Isolation of mitogenic substance from sclerotia of Sclerotinia sclerotiorum IFO 9395 extracted with phosphate buffer.

The buffer extracts (3S) of sclerotia of Sclerotinia sclerotiorum IFO 9395 contained mitogenic substance(s) to murine splenocytes (Shinohara et al. Chem. Pharm. Bull., 38, 2219 (1990)). Although the native 3S was slightly mitogenic, heating of 3S induced significant mitogenic activity. To isolate the mitogen, we separated 3S by ion-exchange and gel filtration chromatographies. The isolated mitogen, named sclerogen, has a molecular mass of 32 kilodaltons (kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the isoelectric point (pI) of 5.9 by chromatofocusing. Sclerogen was significantly mitogenic in vitro against murine splenocytes after heat denaturation, and also showed the augmentation of the primary mixed lymphocyte reaction (MLR) in vitro. However, sclerogen did not show the activation of an alternative pathway of complement and hemagglutination activity. These results suggest that sclerogen is a unique mitogen which differs from lectins and shows mitogenicity after heat denaturation.     

Separation of the hot water extracts of sclerotia of Sclerotinia sclerotiorum IFO 9395 into mitogenic and antitumor-active subfractions

The hot water extract of sclerotia of Sclerotinia sclerotiorum IFO 9395 (TSHW) was divided into representative fractions by ammonium sulfate and ethanol precipitations, and (1----3)-beta-D-glucanase treatment. The ammonium sulfate and ethanol precipitations gave a (1----3)-beta-D-glucan fraction (TSG) and a mannan fraction (TSM). After the degradation of (1----3)-beta-D-glucan in TSHW by (1----3)-beta-D-glucanase treatment, a water-insoluble protein fraction (EDP) and supernatant (EDS) were obtained. Among these fractions, the mitogenic and antitumor activities were mainly observed in EDP and TSG, respectively. On the other hand, the stimulatory effect on the reticuloendothelial system was mainly found in EDP and EDS, and a weak effect was observed in TSG. These findings suggest that the mitogenic and antitumor activities of TSHW were mainly due to the protein and (1----3)-beta-D-glucan, respectively, and that the mitogenic substance (EDP) is tightly bound to (1----3)-beta-D-glucan (TSG) in TSHW, accounting for its solubility in aqueous solution.     

Synthesis of the antifungal beta-1,3-glucan synthase inhibitor CANCIDAS (caspofungin acetate) from pneumocandin B0

A novel three-step synthesis of the highly functionalized antifungal agent CANCIDAS (caspofungin acetate, 2) is described, starting from the natural product pneumocandin B0 (1). The highlights of the synthesis include a stereoselective formation of a phenylthioaminal, a remarkable chemoselective, high-yielding, one-step borane reduction of a primary amide, and a stereoselective substitution of the phenylthioaminal with ethylenediamine producing 2 in a 45% overall yield.     

Effect of photoinitiator on the molar mass distribution obtained from a pulsed laser polymerization

The choice of the photoinitiator is not usually regarded as being as important consideration in attempting to determine the value of the propagation rate coefficient k_p from a pulsed laser-initiated polymerization (PLP). It is shown that in fact the choice of the photoinitiator can profoundly influence the success of such experiments. Specially, for a number of monomers it was found that the successful determination of k_p is essentially impossible when 1,1-azodicyclohexanecarbonitrile is employed as a photoinitiator. The likely reason for this phenomenon is discussed from which it would seem appropriate to be wary in using any azo compound as a PLP photoinitiator. From PLP experiments with a non-azo photoinitiator, ambient pressure k_p has been determined for bulk polymerization of methyl methacrylate over an extended temperature range.     

Effect of pyrolysis conditions on the properties of carbonaceous nanofibers obtained from freeze-dried cellulose nanofibers

Carbonaceous nanofibers (CsNFs) were produced by pyrolysis of cellulose nanofibers synthesised from wood pulp using a top-down approach. The effects of heat treatment conditions on the thermal, morphological, crystal and chemical properties of the CsNFs were investigated using TGA, SEM, XRD and FT-IR, respectively. The results showed that heat treatment conditions around the thermal decomposition temperature of cellulose greatly influence the morphology of resulting materials. Slow heating rates (1 °C/min) between 240 and 400 °C as well as prolonged isothermal heat treatment (17 h) at 240 °C were necessary to avoid destruction of the original fibrous morphology in carbonized nanofibers. On the other hand, such heat treatment had little effect on micron sized fibers. The optimized heat treatment conditions led to the release of oxygen and hydrogen from cellulose before thermal breakdown of glycosidic rings, which in turn prevented depolymerization and tar formation, resulting in the preservation of the fibrous morphology.     

Effect of pressure on the structure of composite chitosan films obtained from solutions in carbonic acid

The effect of pressure in solutions of chitosan in carbonic acid with the AgNO₃ precursor on the structure of cast nanocomposite films with silver nanoparticles has been studied for the first time. The size of silver nanoparticles can be controlled by varying pressure in carbonic acid.     

Effect of polyhydroxysteroids from starfish and brittle stars on the activity of β-1,3-glucanases

The action of sulfated polyhydroxysteroids from starfish and brittle stars on the activity of β-1,3-glucanases from various sources has been investigated. All the substances activated the exoglucanase L_II, nine out of ten activated L_e, and seven out of ten of the sulfates activated the endoglucanase L_III. Other endo-β-1,3-glucanases from marine molluscs were specifically inhibited by the steroid sulfates investigated, and it was shown that the efficiency of inhibition depends on the structural features of the molecules of these inhibitors. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Division of the Russian Academy of Sciences [TIBOKh DVO RAN], Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 647–650, September–October, 1994.     

Effect of different reagents to adjust the pH on the synthesis,structure, and properties of Au/SiO2 catalysts obtained from aqueous HAuCl4

Research on Chemical Intermediates - We compared the structures and properties of Au/SiO2 catalysts obtained from aqueous HAuCl4 using different reagents to adjust the pH value. The speciation of...     

Effects of arsenobetaine,a major organic arsenic compound in seafood,on the maturation and functions of human peripheral blood monocytes,macrophages and dendritic cells

We examine the in vitro immunotoxicity of synthetically pure arsenobetaine [AsBe; trimethyl (carboxymethyl) arsonium zwitterion], which is a major organic arsenic compound in seafood, on various human immune cells, such as peripheral blood monocytes, monocyte‐derived macrophages and monocyte‐derived dendritic cells (DCs). In particular, we examine the differentiation of monocytes into macrophages or DCs by comparing the effects of AsBe with those pentavalent inorganic arsenate. AsBe neither enhanced nor inhibited the differentiation of human monocytes into macrophages or DCs, and also did not affect their various immune functions. Furthermore, AsBe had no cytolethality in monocyte‐derived macrophages or DCs even at a concentration of 5 mmol l⁻¹. In contrast, inorganic arsenate showed strong cytolethality in these human immune cells in vitro at micromolar concentrations. These data indicate that the organic arsenic compound AsBe in seafood has no in vitro immunotoxicity in human immune cells. Copyright © 2004 John Wiley & Sons, Ltd.     

Solvent Effect on the Volume of the Diels-Alder Reaction between Tetracyanoethylene and trans,trans-1,4-Diphenyl-1,3-butadiene

From the partial molar volumes of tetracyanoethylene, trans,trans-1,4-diphenyl-1,3-butadiene, and their Diels-Alder adduct, the volumes of the reaction in a series of solvents at 25°C (cm³ mol^{- 1}) were calculated: in dioxane, -26.4; in chloroform, -34.9; in ethyl acetate, -34.5; in acetonitrile, -4.4; in cyclohexanone, -34.0; in 1,2-dichloroethane, -31.8; in benzene, -26.9; in toluene, -24.5; in o-xylene, -21.1; and in mesitylene, -16.9. The solvent effects on the activation and reaction volumes and on the partial molar volumes of the reactants, activated complex, and adduct were discussed.