Biological Activity of High-Purity β-1,3-1,6-Glucan Derived from the Black Yeast Aureobasidium pullulans: A Literature Review

The black yeast Aureobasidium pullulans produces abundant soluble β-1,3-1,6-glucan-a functional food ingredient with known health benefits. For use as a food material, soluble β-1,3-1,6-glucan is produced via fermentation using sucrose as the carbon source. Various functionalities of β-1,3-1,6-glucan have been reported, including its immunomodulatory effect, particularly in the intestine. It also exhibits antitumor and antimetastatic effects, alleviates influenza and food allergies, and relieves stress. Moreover, it reduces the risk of lifestyle-related diseases by protecting the intestinal mucosa, reducing fat, lowering postprandial blood glucose, promoting bone health, and healing gastric ulcers. Furthermore, it induces heat shock protein 70. Clinical studies have reported the antiallergic and triglyceride-reducing effects of β-1,3-1,6-glucan, which are indicators of improvement in lifestyle-related diseases. The primary and higher-order structures of β-1,3-1,6-glucan have been elucidated. Specifically, it comprises a single highly-branched glucose residue with the β-1,6 bond (70% or more) on a backbone of glucose with 1,3-β bonds. β-Glucan shows a triple helical structure, and studies on its use as a drug delivery system have been actively conducted. β-Glucan in combination with anti-inflammatory substances or fullerenes can be used to target macrophages. Based on its health functionality, β-1,3-1,6-glucan is an interesting material as both food and medicine.

Action of an endo-β-1,3(4)-glucanase on cellobiosyl unit structure in barley β-1,3:1,4-glucan

β-1,3:1,4-Glucan is a major cell wall component accumulating in endosperm and young tissues in grasses. The mixed linkage glucan is a linear polysaccharide mainly consisting of cellotriosyl and cellotetraosyl units linked through single β-1,3-glucosidic linkages, but it also contains minor structures such as cellobiosyl units. In this study, we examined the action of an endo-β-1,3(4)-glucanase from Trichoderma sp. on a minor structure in barley β-1,3:1,4-glucan. To find the minor structure on which the endo-β-1,3(4)-glucanase acts, we prepared oligosaccharides from barley β-1,3:1,4-glucan by endo-β-1,4-glucanase digestion followed by purification by gel permeation and paper chromatography. The endo-β-1,3(4)-glucanase appeared to hydrolyze an oligosaccharide with degree of polymerization 5, designated C5-b. Based on matrix-assisted laser desorption/ionization (MALDI) time-of-flight (ToF)/ToF-mass spectrometry (MS)/MS analysis, C5-b was identified as β-Glc-1,3-β-Glc-1,4-β-Glc-1,3-β-Glc-1,4-Glc including a cellobiosyl unit. The results indicate that a type of endo-β-1,3(4)-glucanase acts on the cellobiosyl units of barley β-1,3:1,4-glucan in an endo-manner.

Barley low molecular weight β-glucan potently induces maturation of mouse dendritic cells

BACKGROUND

Accumulating evidence indicates that non-toxic immunostimulants with strong differentiation/maturation-inducing activity for dendritic cells (DCs) might be useful for preventing or even curing cancer.

MATERIALS AND METHODS

Mouse bone marrow (BM) cells were cultured in the presence of various glucans and their differentiation/maturation-inducing activities were compared by measuring cytokines secreted in the culture medium.

RESULTS

Barley-derived β-glucan with an average molecular weight of 2 kDa (BBG-Low) remarkably stimulated the formation of mature DCs from immature mouse DCs. The amount of interleukin-6 produced by sequential treatment of BM cells with granulocyte-macrophage colony-stimulating factor and 10 μg/mL of BBG-Low was approximately 30 times higher than that obtained by a similar sequential treatment using barley β-glucan of 40-70 kDa instead of BBG-Low.

CONCLUSION

BBG-Low induces the formation of mature DCs from immature DCs and suggests that BBG-Low will be useful as a potent nontoxic immunostimulator.

Induction of IFN-γ by a highly branched 1,3-β-d-glucan from Aureobasidium pullulans in mouse-derived splenocytes via dectin-1-independent pathways

We have previously elucidated the precise structure of a unique type of 1,3-β-D-glucan, AP-FBG (Aureobasidium pullulans-fermented β-D-glucan), from the fungus A. pullulans and found that AP-FBG strongly induced the production of various cytokines in DBA/2 mouse-derived splenocytes in vitro. However, the mechanism(s) of action of AP-FBG on in vitro mouse primary cells have not been characterized in detail. Herein, we report that the production of IFN-γ in DBA/2 mouse-derived splenocytes by AP-FBG was not inhibited following treatment with an anti-dectin-1 neutralizing antibody. In addition, AP-FBG not only failed to activate dectin-1-mediated signaling pathways, examined by a reporter gene assay but also failed to bind to dectin-1, a pivotal receptor for 1,3-β-D-glucan. Taken together, AP-FBG induced cell activation via dectin-1-independent pathways.

Granulocyte macrophage colony-stimulating factor is required for cytokine induction by a highly 6-branched 1,3-β-D-glucan from Aureobasidium pullulans in mouse-derived splenocytes

We have previously obtained and elucidated the precise structure of a highly branched 1,3-β-D-glucan (with 6-monoglucopyranosyl side chains), Aureobasidium pullulans-fermented β-D-glucan (AP-FBG), from the fungus A. pullulans. However, the mechanism(s) of the effects of AP-FBG on in vitro mouse primary cells have not been analyzed in detail. Herein, we report that the induction of cytokines by AP-FBG was dependent on the existence of a granulocyte macrophage colony-stimulating factor (GM-CSF); this is similar way to be a typical 1,3-β-D-glucan from Sparassis crispa (SCG), which is a 1,3-β-D-glucopyranosyl backbone with single 1,6-β-D-glucopyranosyl side branching units every three residues. In other words, the production of cytokines in DBA/2-mouse-derived splenocytes by AP-FBG was completely hampered by an anti-GM-CSF neutralizing monoclonal antibody. Furthermore, the addition of exogenous GM-CSF to C57BL/6-derived splenocytes, which are less sensitive to AP-FBG, induced the production of cytokines by AP-FBG. Therefore, GM-CSF is indispensable for the induction of cytokines by AP-FBG in mouse-derived splenocytes. This finding has provided a new insight into our understanding of the actions of β-D-glucan but will also aid in the design and development of more effective β-D-glucan agents.

A highly branched 1,3-beta-D-glucan extracted from Aureobasidium pullulans induces cytokine production in DBA/2 mouse-derived splenocytes

We recently elucidated the structure of a highly branched 1,3-beta-D-glucan with 6-monoglucopyranosyl side chains, extracted from Aureobasidium pullulans (AP-FBG). Although the biological effects of beta-D-glucans are known to depend on their structures, the effects of a highly branched 1,3-beta-D-glucan on the production of cytokines by leukocytes in mice have not yet been elucidated. In this study, we found that AP-FBG strongly induced the production of various cytokines, especially Th1 cytokines (e.g., IFN-gamma and IL-12p70) and Th17 cytokines (e.g., IL-17A), but did not induce the production of IL-4, IL-10, and TNF-alpha in DBA/2 mouse-derived splenocytes in vitro.

PCR-RFLP genotypes associated with quinolone resistance in isolates of Flavobacterium psychrophilum

A novel genotyping method for epizootiological studies of bacterial cold-water disease caused by Flavobacterium psychrophilum and associated with quinolone resistance was developed. Polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) was performed on 244 F. psychrophilum isolates from various fish species. PCR was performed with primer pair GYRA-FP1F and GYRA-FP1R amplifying the A subunit of the DNA gyrase (GyrA) gene, which contained the quinolone resistance determining region. Digestion of PCR products with the restriction enzyme Mph1103I showed two genotypes, QR and QS. The difference between these genotypes was amino acid substitutions at position 83 of GyrA (Escherichia coli numbering). The genotype QR indicated an alanine residue at this position associated with quinolone resistance in F. psychrophilum isolates. Of the 244 isolates tested in this study, the number of QR genotype isolates was 153 (62.7%). In isolates from ayu (n=177), 146 (82.5%) were genotype QR. With combination of this technique and previously reported PCR-RFLP genotyping, eight genotypes were observed in F. psychrophilum isolates. Using this genotyping system, the relationships between genotype and host fish species, or locality of isolation, were analysed and are discussed.

Comparison between the characteristics of follicular fluid and the developmental competence of bovine oocytes

There are great differences in the developmental competence of oocytes collected from individual cows. Oocytes grow and mature in the follicular fluid (FF). In the present study, characteristics of the FF of each ovary and the developmental competence of enclosed oocytes were investigated, and these data were then compared. A total of 37 pairs of ovaries were collected from beef heifers. The concentration of magnesium (Mg), aspirate aminotransferase (AST), nonesterified fatty acids (NEFA), and lactate dehydrogenase (LDH) in the FF were great compared with serum standard. Several significant correlations among these characteristics were detected. Forty-eight hours after fertilization, the stage of embryo development at an advanced developmental stage (>6 cell stage) is related to the rate of blastulation 8 days after fertilization. In addition, a significantly positive or negative correlation was observed between the developmental competence (the rate of cleavage in the embryo and blastulation) and the concentration of the icterus index (ICT) or blood urea nitrogen (BUN) in the FF. In conclusion, the quality of oocytes is affected by the environment in the follicle, and BUN or ICT is a predictable index of the developmental competence of oocytes.

Effects of seirogan (wood creosote) on propulsive colonic motility and stool characteristics in ambulatory mini-pigs

Our goal was to determine whether Seirogan, an herbal medicine used as an antidiarrheal agent, modifies colonic function, including motility. Experiments were performed on four female Yucatan mini-pigs with established permanent cecal fistulas providing direct access to the colon. Long-term recordings of proximal colonic motility were accomplished by a solid-state probe (six pressure ports 10 cm apart), and a motility index was calculated. Stool viscosity was also measured. The laxative bisacodyl (15 mg/kg) was used to induce colonic motility (increase in motility index) and stool softening, prior to investigating the effect of Seirogan (2-15 mg/kg per os twice a day) or a vehicle control. Seirogan (15 mg/kg), but not the placebo, reversed the bisacodyl-induced stool softening and restored the motility index to normal values by reducing the number of propagating contractions. Taken together the results suggest that inhibition of proximal colonic motility by Seirogan may contribute to its antidiarrheal action.

Identification of a putative vacuolar serine protease gene in the rice blast fungus, Magnaporthe grisea

We identified and cloned a gene designated SPM1, encoding a serine protease from the rice blast fungus Magnaporthe grisea. SPM1 is a single-copy gene, encoding a subtilisin-like serine protease with 536 amino acids. Analyses of the deduced amino acid sequence of SPM1 suggested that SPM1 would be localized in a vacuole, an important organelle in pathogenicity.

No significant differences were observed in the amounts of DNA strand breaks produced by copper between male and female liver cells of long-evans cinnamon (LEC) strain rats

The amounts of DNA single strand breaks that are oxidative damage produced by copper were examined by comet assay in the liver cells of an inbred strain of Long-Evans Cinnamon (LEC) rats that spontaneously develops fulminant hepatitis. At 4 weeks of age, copper contents in the liver of LEC rats were approximately 30-fold higher than those of WKAH rats that are control rats used in the present study. Copper accumulated in the liver of LEC rats in an age-dependent manner and no significant differences were observed between copper contents in the livers of males and females at each week of age from 4 to 15 weeks. No significant amounts of DNA strand breaks were found in the liver cells of both male and female WKAH rats from 4 to 15 weeks of age. DNA strand breaks were produced in the substantial population of LEC rat liver cells at 10 weeks of age and induced in an age-dependent manner from 10 to 15 weeks of age. The amounts of DNA strand breaks produced by copper accumulation in the liver cells of female LEC rats are not more abundant than those in the cells of male rats, although it has been reported that hepatitis in female rats is more serious than that in male rats.

Lack of oncogenicity of wood creosote, the principal active ingredient of Seirogan, an herbal antidiarrheal medication, in Sprague-Dawley rats

Seirogan, an herbal medicine containing wood creosote (tablets, 10.0% w/w), has been developed and marketed for almost a century in various countries for the control of acute diarrhea and treatment of associated symptoms, such as abdominal cramping. Wood creosote (CAS no. 8021-39-4) is a mixture of simple phenolic compounds, including guaiacol and creosol and related compounds, and is chemically distinct from, and should not be confused with, coal tar creosote, a known carcinogen. In the current study, the oncogenic potential of wood creosote was assessed in a 96/103-week oral gavage study in Sprague-Dawley rats. Groups of 60 rats/sex received wood creosote at dose levels of 20, 50, or 200 mg/kg body weight [bw]/day. An additional group of rats received the vehicle, 0.5% carboxymethylcellulose in deionized, distilled water, at the same dose volume as the treatment groups (10 ml/kg) and served as the controls. Treatment-related decreases in survival, body weight, and food consumption, as well as increased incidences of clinical signs that included rales, decreased activity, and salivation, were noted at 200 mg/kg bw/day when compared with the control group. There was an increased incidence of reddened and edematous lungs in rats from the 200 mg/kg bw/day group that died during the study. The lung findings were suggestive of test article aspiration during dose administration or agonal aspiration preceding and possibly resulting in death, especially because these observations were not seen in animals that survived to scheduled sacrifice. Additionally, phenols are generally recognized as having corrosive properties. There were no changes in clinical pathology and no increases in neoplastic or non-neoplastic lesions, excluding the lung findings, related to treatment with wood creosote at any dose level. Although the results of this study indicate that the maximum tolerated dose of wood creosote was met or exceeded at 200 mg/kg bw/day, there was no evidence of oncogenicity at any dose level. The lack of any evidence of oncogenicity supports the safety profile of the active ingredient in Seirogan, wood creosote.

In vitro effects of wood creosote on enterotoxin-induced secretion measured electrophysiologically in the rat jejunum and colon

Secretory diarrhea occurs when the balance between intestinal absorption and secretion is disturbed by excessive secretion caused by enterotoxins produced by the pathogen. Wood creosote has long been used as a traditional antidiarrheal remedy. The goal of our study was to extend our knowledge about the antisecretory action of wood creosote against Escherichia coli enterotoxin-induced secretion in the small intestine and colon. Experiments were performed in mucosal sheets of rat jejunum and colon which were stripped of the external muscle layers to eliminate interactions with smooth muscle activity and local blood flow. Mucosal sheets were placed in modified Ussing chambers and hypersecretory conditions were induced by heat-labile (LT) or heat-stable (STa) E. coli enterotoxins added cumulatively (0.01-10 microg/ml) to the mucosal bathing solution. Intestinal secretion was monitored electrophysiologically as transmucosal short circuit current (Isc). LT induced a concentration-dependent increase in Isc in the rat jejunum, with no effect in the colon. In contrast, STa induced a significant increase in colonic Isc, without causing any change in Isc across the jejunum. In separate experiments the effects of increasing concentrations of wood creosote (0.1-50 microg/ml), added to the mucosal or serosal bathing solution, were examined against the secretory responses induced by LT or STa. In the small intestine the antisecretory activity of wood creosote against LT-induced secretion was more potent following serosal application, whereas in the colon wood creosote inhibited STa-induced secretion with equal potency following either serosal or mucosal addition. In summary, our findings demonstrate that wood creosote possesses antidiarrheal activity suppressing E. coli enterotoxin-induced secretion in both the small intestine and colon.

Hepatic copper accumulation induces DNA strand breaks in the liver cells of Long-Evans Cinnamon strain rats

Effects of accumulation of copper and iron on the production of DNA strand breaks were investigated in Long-Evans Cinnamon (LEC) strain rats that spontaneously develop fulminant hepatitis. Copper and iron accumulated in the liver of LEC rats in an age-dependent manner from 4 to 15 weeks. Low-copper food prevented the accumulation of copper in the liver, but did not prevent accumulation of iron. When the amounts of DNA single strand breaks were estimated by comet assay, the number of DNA strand breaks in the liver cells of rats fed standard food increased with age from 4 to 15 weeks. The number of DNA strand breaks in the liver cells from rats fed low-copper food were the same as those of rats at 4 weeks of age. Thus, the copper accumulation in the liver of LEC rats induced DNA strand breaks, but accumulation of iron did not.

Comparison of the antidiarrheal effects of wood creosote and loperamide in the rat jejunum and colon in vitro

Wood creosote, a mixture of guaiacol, creosol and related compounds, has long been used as an antidiarrheal agent. The goal of our study was to investigate the antisecretory effect of wood creosote and to compare it to the effect of loperamide, a synthetic opioid widely used in the treatment of diarrhea. Experiments were performed in rat jejunal and colonic mucosal sheets, mounted in modified Ussing chambers. Active electrogenic transport was monitored electrically as short circuit current (Isc) and hypersecretory responses were induced by acetylcholine (ACh). Neither loperamide nor wood creosote had any significant effect on basal lsc, when added to the serosal bathing solution at concentrations of 0.1-50microg/ml. In contrast, under hypersecretory conditions, both agents showed concentration-dependent (0.1--100microg/ml) antisecretory effects inhibiting ACh-induced responses in the jejunum and colon. However, the effects suggest regional differences, with loperamide being most potent in the jejunum, while wood creosote showed equal potency in both jejunum and colon. Based upon these in vitro findings, we conclude that like loperamide, the antidiarrheal action of wood creosote is due, at least in part, to its antisecretory activity.

Anti-diarrhoeal effects of seirogan in the rat small intestine and colon examined in vitro

BACKGROUND

Seirogan is a beechwood extract composed of guaiacol, creosol and other related phenolic compounds which is widely used as an anti-diarrhoeal agent in Asia. Abnormalities in water and electrolyte transport are often the cause of diarrhoea, but the mechanism of action of seirogan on small intestinal and colonic mucosal ion transport is unknown.

AIM

To examine the effect of seirogan on electrogenic ion transport in vitro.

METHODS

Sheets of rat jejunum and colon were mounted in Ussing chambers, and transmural potential difference (PD) was used as an electrical marker of changes in mucosal ion transport. Hypersecretory conditions were induced by acetylcholine (ACh).

RESULTS

Serosal or mucosal application of seirogan (0.1-100 microg/mL) decreased basal jejunal transmural PD. Pre-treatment of the tissue with the neurotoxin, tetrodotoxin, did not inhibit the seirogan-induced changes in basal electrical activity. Seirogan had no effect on basal transmural PD in the ileum and colon. Under ACh-induced hypersecretory conditions in the small intestine and colon, addition of serosal or mucosal seirogan produced antisecretory effects determined indirectly by measurement of transmural PD.

CONCLUSION

The ability of seirogan to decrease basal transmural PD in the jejunum, and inhibit the ACh-induced electrical responses, may contribute to its anti-diarrhoeal action.

Suppression of enterotoxin-induced intestinal fluid secretion by wood creosote

Wood creosote suppresses intestinal fluid secretion induced by heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli (ETEC). When rabbit jejunum is ligated into a 5-cm segment and LT is administered locally, it actively induces intestinal fluid secretion in a dose-dependent manner. Local administration of wood creosote together with a fixed dose of LT suppressed the LT-induced fluid secretion in a dose-dependent manner. At a 50-ng/segment dose of LT, 7.4 +/- 1.1 ml (n = 5) of fluid is secreted into an intestinal segment; coadministration of wood creosote (150 micrograms/segment) significantly (p < 0.01) suppressed the fluid secretion to 2.4 +/- 2.3 ml. Based on these results, we conclude that the antidiarrheal activity of wood creosote is attributable to its antisecretory or proabsorptive effect (or both) on the intestine.

Effect of ethanol on the development and maturation of synapses in the rat hippocampus: a quantitative electron-microscopic study

The effects of chronic ethanol administration on the development and maturation of synapses in the strata radiatum and lacunosum-moleculare of CA1 in the hippocampus were quantitatively examined in rats exposed to ethanol for the entire period of fetal life as well as the whole period of postnatal life. Synapse densities in the strata radiatum and lacunosum-moleculare of the ethanol-treated group were significantly lower than those of the control group at 2, 14, 21, and 70 days of age. However, the rates of density reduction did not change between either of the strata that receive different groups of afferent fibers. The ratio of axospinous to axoshaftic synapses also did not change between control and ethanol-treated groups. These data suggest that chronic administration of ethanol reduces the density of synapses in this area and that this effect is not specific to neither the type of afferent fibers nor the type of synapses.

[Effect of ethanol on the development and maturation of synapses in the rat hippocampus]

Rats of both sexes were exposed to ethanol during the entire period of the fetal life as well as the whole period of postnatal ages, and their brains were investigated at 2, 7, 14, 21, and 70 days postnatally. Control animals were examined at each age. Densities of synapses in the strata radiatum and lacunosum-moleculare of CA1 in the hippocampus were analyzed by quantitative ultrastructural techniques. Densities of all synapses in the strata radiatum and lacunosum-moleculare in ethanol-treated group were significantly lower than those of control group on 2, 14, 21 and 70 days. However, there were no significant differences in the ratio of axo-spinous to axo-shaftic synapses between control and ethanol-treated group. In addition, in regard to the rate of reduction in densities of all synapses, no change was detectable between both strata that receive different groups of afferent fibers. These data suggest that chronic administration of ethanol during the fetal and postnatal ages reduces the synaptic density in this area, and that this effect is neither specific to types of synapses nor to sorts of afferent fibers.

[The study of Chinese herbal medicinal prescription with enzyme inhibitory activity. VI. The study of makyo-kanseki-to with adenosine 3',5'-cyclic monophosphate phosphodiesterase]

A Chinese herbal medicinal prescription, Makyo-kanseki-to, was studied for the inhibitory activity of adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase. The effect for the inhibitory activity of cAMP phosphodiesterase by combination with constituent crude drugs of the prescription was studied. Gypsum acted as a mitigatory component for Ephedra herb and Glycyrrhiza in cAMP phosphodiesterase inhibition test.

Thermally induced conformational transition of double-stranded xanthan in aqueous salt solutions

The thermally induced conformational transition of double-stranded xanthans (degree of pyruvate substitution, DSp = 0.45) having Mw = 3.1, 5.7, and 20.3 x 10(5) has been studied in aqueous salt solutions by high-sensitivity differential scanning calorimetry (DSC). The double strandedness of these samples in the ordered conformation was ascertained by the value of mass per unit length, ML = 2090 +/- 270 g mol-1 nm-1, which was determined from the contour length obtained by electron microscopic observations and the molecular weight by light scattering measurements. The temperature at half completion of the transition T 1/2 for these samples increased linearly with the logarithm of the cation (Na+, K+) concentration. The plot of 1/T1/2 vs the natural logarithm of cation (Na+) concentration in mM for the sample with Mw = 5.7 x 10(5) (15-SX) yielded the equation 10(3)/T1/2 = 3.45-0.159 ln [Na+]. The specific enthalpy delta hcal for 15-SX, essentially independent of salt concentration above 20 mM, was 8.31 +/- 0.39 J/g (SD, n = 6). No systematic dependence of molecular weight on the transition temperature and the enthalpy was observed. Application of the Manning polyelectrolyte theory to the system using the DSC data suggested that the separation of the double strand of xanthan into two single chains was not completed at the temperature where the endothermic peak was finished. This suggestion is consistent with recent findings by light scattering measurements as a function of temperature. Our DSC study was extended to include four other samples from various sources. It was found that T1/2 and delta hcal depend on the pyruvate contents of the samples. For example, the t1/2 (t1/2/degrees C = T1/2/K - 237.15) values for samples with high pyruvate content (DSp = 0.9) and depyruvated (DSp = 0.14) in 20 mM aqueous NaCl were 48.8 and 85.3 degrees C, respectively. Two other samples showed relatively broad DSC curves having shoulders, which were resolved into two independent components. Thermodynamic parameters for each component were examined as a function of salt concentration, and the results obtained were interpreted in terms of the heterogeneity of the pyruvate content of the samples.

Inhibition of adenosine 3',5'-cyclic monophosphate phosphodiesterase by flavonoids from licorice roots and 4-arylcoumarins

Isoliquiritigenin, glabridin, licoarylcoumarin and licoricidin were identified as strong inhibitors of adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase in waste materials which were obtained during the industrial extraction of glycyrrhizin from licorice roots. The structure-activity relationships of 12 flavonoids from licorice roots and 34 4-arylcoumarins were studied. In 4-arylcoumarins, 5,7-dihydroxy derivatives were generally highly inhibitory towards cAMP phosphodiesterase.

[The study of Chinese herbal medicinal prescription with enzyme inhibitory activity. IV. The study of the prescription containing mineral drug with adenosine 3',5'-cyclic monophosphate phosphodiesterase]

Twenty five Chinese herbal medicinal prescriptions containing gypsum, kaolin, longgu, oyster shell and sodium sulfate were studied for the inhibitory activity of adenosine 3',5'-cyclic monophosphate phosphodiesterase. The inhibitory activity of 15 prescriptions without mineral drug was higher than that of each original prescription. On the contrary, four were lower and six were not recognized to be different. All 11 prescriptions containing gypsum with an exception increased the inhibitory activity by removing gypsum. The half prescriptions containing kaolin or sodium sulfate also increased the inhibitory activity by removing the drug.

[The study on Chinese herbal medicinal prescription with enzyme inhibitory activity. III. The study of mao-to with adenosine 3',5'-cyclic monophosphate phosphodiesterase]

Mao-to, a Chinese herbal medicinal prescription was studied for the inhibitory activity of adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase. The inhibitory activity for this enzyme depended mainly on Ephedra herb and Glycyrrhiza in this prescription. Apricot kennel acted as a mitigatory component for Ephedra herb in cAMP phosphodiesterase inhibitory test. In ephedrine and the related compounds the inhibitory activity of cAMP phosphodiesterase was not shown.

[The study on Chinese herbal medicinal prescription with enzyme inhibitory activity. II. The study of kanbaku-taiso-to with adenosine 3',5'-cyclic monophosphate phosphodiesterase]

A Chinese herbal medicinal prescription, Kanbaku-taiso-to, was studied for the inhibitory activity of adenosine 3',5'-cyclic monophosphate (cAMP) phosphodiesterase. The effect for the inhibitory activity of cAMP phosphodiesterase in combination with constituent crude drugs and difference in kind of crude drugs of the prescription were studied. The inhibitory activity of the prescriptions which were combined with low protein content wheat were higher than that with high protein content wheat.

Migration of bipolar subependymal cells, precursors of the granule cells of the rat olfactory bulb, with reference to the arrangement of the radial glial fibers

In order to examine the relationship between radial glial fibers and the migrating bipolar subependymal cells which are considered to be post-mitotic precursors of granule cells in the rat olfactory bulb, the arrangement of radial glial fibers along the anterior lateral and olfactory ventricles was analysed by Golgi techniques, immunohistochemical demonstration of glial fibrillary acidic protein, and electron microscopy. In rats during their first 3 weeks of life, the bipolar subependymal cells migrate along the anterior lateral and olfactory ventricles into the center of the olfactory bulb, whereas the radial glial fibers radiating from the ventricular surface are arranged rather perpendicularly to the direction of migration of bipolar cells. Hence radial glial fibers in this region are not considered to act as guides for the rostralwards migration of subependymal cells.

A differential scanning calorimetric study of the conformational transitions of schizophyllan in mixtures of water and dimethylsulfoxide

The thermal conformational transitions of two sonicated samples of schizophyllan were studied in water-dimethylsulfoxide (DMSO) mixtures by high-sensitivity differential scanning calorimetry (DSC). Two transitions were observed over most of the range of solvent compositions. These were assigned to an internal change of the triple helix [T. Itou et al. (1986) Macromolecules 19, 1234-1240] and a triple-helix-single-coil transition [T. Sato et al. (1981) Carbohydr. Res. 95, 195-204], respectively. In water, the former transition observed at lower temperature for a low molecular weight sample, U-1, is centered at 3 degrees C and characterized by the specific enthalpy, delta hcal = 3.29 J g-1. A higher molecular weight sample, M-2, showed this transition at 7 degrees C with delta hcal = 4.39 J g-1. The transition temperature for both samples increased with increasing DMSO concentration up to about 50 degrees C at 70 weight % DMSO, and then rapidly decreased with increasing DMSO concentration, with about 3 degrees C higher for M-2 than for U-1 over the DMSO concentration. The transition was not observed when the concentration of DMSO exceeded 87%. It was found that delta hcal for both samples was a linear function of t 1/2, the temperature of half-completion in degrees C, delta hcal = 0.177t + 2.96. The triple helix-coil transition was observed at around 127 degrees C for U-1 and above 130 degrees C for M-2 in the range of DMSO composition below about 70%. The transition temperature decreased with increasing DMSO concentration at above 70%, and the transition finally disappeared when the DMSO concentration exceeded 90%. The plot of delta hcal vs. t 1/2 for the transition of both samples gave a linear relation, delta hcal = 0.253t - 10.58. The reversibility of the transition at lower temperature was demonstrated by the reversibility of the curves when the first heating was stopped before the second transition. Once the heating was performed over the second transition, the reheating DSC curves showed several endothermic peaks, indicating the irreversibility of the transition and heterogeneity in the conformation of the heated schizophyllan.

Hydrolysis of aryl beta-maltotriosides by sweet potato beta-amylase and soybean beta-amylase

Sweet potato beta-amylase [EC 3.2.1.2, alpha 1,4-D-glucan maltohydrolase]-catalyzed hydrolyses of aryl beta-maltotriosides with substituents, NO2-, Cl-, and Br- at the o-, m-, and p-positions in the phenyl ring were studied at pH 4.8 and 25 degrees C. The hydrolyses of a few of the maltotriosides by soybean beta-amylase [EC 3.2.1.2, alpha-1,4-D-glucan maltohydrolase] were also studied at pH 5.4 and 25 degrees C. It was found that the aryl beta-maltotriosides were preferentially hydrolyzed into maltose and aryl beta-D-glucosides by both beta-amylases. The Michaelis constant Km and the molecular activity ko were determined for the hydrolyses of these maltotriosides and compared with those of maltotriose and maltotetraose. Aryl beta-maltotriosides were more rapidly hydrolyzed than maltotriose by a factor of 30--80, and more slowly hydrolyzed than maltotetraose by a factor of 10--30, depending on the kinds of substituents. The rapid hydrolysis of aryl beta-maltotrioside as compared with maltotriose may be due to the interaction of an aryl group with the subsite of beta-amylase. This is in contrast with glucoamylase [EC 3.2.1.3, alpha-1,4-D-glucan glucohydrolase] of Rhizopus niveus-catalyzed hydrolysis of phenyl beta-maltoside, whose phenyl group does not interact so much with the subsite of the enzyme.