Kazuyuki Oku

Serological tests for monitoring Helicobacter pylori eradication treatment.

Metabolic interaction between the intestinal microflora and the host has been suggested to play a role in the pathogenesis of chronic inflammatory bowel disease. Elemental or low-fat, low-residual diets in patients with Crohns disease or ulcerative colitis are reported to decrease anaerobic bacteria and to change the composition of the intestinal microflora. We examined the effect of an indigestible agent, 4G-β-d-galactosylsucrose (lactosucrose), which is selectively utilized by intestinalBifidobacterium, on the composition of the intestinal microflora. After the administration of lactosucrose to two patients with Crohns disease and five patients with ulcerative colitis for 2 weeks, significant induction of the growth ofBifidobacterium was observed, and significant reduction in the population level of Bacteroidaceae was seen. Bowel movements improved in four patients. The intestinal environment, estimated by measuring fecal pH, fecal levels of short-chain fatty acids and putrid products, and the urinary secretion of indican, also improved in these patients. These results suggest that lactosucrose may be useful for patients with chronic inflammatory bowel disease.Metabolic interaction between the intestinal microflora and the host has been suggested to play a role in the pathogenesis of chronic inflammatory bowel disease. Elemental or low-fat, low-residual diets in patients with Crohns disease or ulcerative colitis are reported to decrease anaerobic bacteria and to change the composition of the intestinal microflora. We examined the effect of an indigestible agent, 4G-β-d-galactosylsucrose (lactosucrose), which is selectively utilized by intestinalBifidobacterium, on the composition of the intestinal microflora. After the administration of lactosucrose to two patients with Crohns disease and five patients with ulcerative colitis for 2 weeks, significant induction of the growth ofBifidobacterium was observed, and significant reduction in the population level of Bacteroidaceae was seen. Bowel movements improved in four patients. The intestinal environment, estimated by measuring fecal pH, fecal levels of short-chain fatty acids and putrid products, and the urinary secretion of indican, also improved in these patients. These results suggest that lactosucrose may be useful for patients with chronic inflammatory bowel disease.

Effects of Dietary Lactosucrose (4G-β-D-galactosylsucrose) on the IgE Response in Mice

In this study, we examined the effects of dietary lactosucrose (LS, a non-digestible oligosaccharide) on the IgE response in mice immunized with ovalbumin (OVA)/alum. In addition to IgG1 and IgG2a responses, the anti-OVA IgE response in mice fed LS diets was dose-dependently suppressed, as compared with the control mice, while the serum total IgG levels were comparable. Moreover, dietary LS feeding inhibited antigen-specific IgE and IgG1 productions even after a second immunization. Regarding with cytokine production, when stimulated in vitro with OVA, splenocytes obtained from LS-fed mice produced a similar level of IFN-γ, and lower levels of IL-4 and IL-5, as compared with the control mice. But IL-10 production by OVA-stimulated splenocytes was augmented in LS-fed mice, suggesting that IL-10 producing cells are responsible for the immunoregulatory effect of LS. Our findings indicate the further possibility that dietary LS supplementation can be used to prevent IgE-mediated allergic diseases.

Experimental and Theoretical Study on the Intermolecular Complex Formation Between Trehalose and Benzene Compounds in Aqueous Solution

The uniqueness of trehalose as a stress protectant may exist in its potential amphiphilic character capable of interacting with both hydrophilic and hydrophobic partners in aqueous solution. To address this issue, we here investigated the interaction between trehalose and aromatic compounds. NMR measurements, including (1)H-(1)H NOESY spectra, provide direct evidence for the formation of stable intermolecular complexes of trehalose with benzene (or p-cresol) in aqueous solution. In addition, corresponding theoretical evidence is provided by calculating the potential mean force as a function of the distance between trehalose and benzene. In the energy minimum structure, the benzene molecule is located only around the hydrophobic side of trehalose where the first hydration shell is not formed. Therefore, it can be concluded that benzene binds to trehalose in a fashion in which dehydration penalty is minimized. Finally, we discuss the possible biological roles of the trehalose-benzene interaction discovered here.

Thermodynamic, hydration and structural characteristics of alpha,alpha-trehalose.

A nonreducing disaccharide, alpha,alpha-trehalose, accumulates endogenously in diverse anhydrobiotic organisms in their dehydrating process or prior to their desiccation, being thought to have a protective function either as a water replacement molecule or as a vitrification agent in the dry state. Trehalose acts also as a protectant against physiological stress, including freezing, ethanol and oxidation. To elucidate the origin of these different functions of this sugar, it is necessary to obtain a deep insight into the physicochemical properties of trehalose at the molecular level. In this review, we focus our attention on the thermodynamic, hydration and structural properties of carbohydrates, and extract the characteristic feature of trehalose. On the basis of these findings, we subsequently discuss the underlying mechanism for protein stabilization by trehalose in solution and for its anitoxidant function on unsaturated fatty acids.

Interaction between Trehalose and Alkaline-Earth Metal Ions

We investigated the interaction between trehalose and alkaline-earth metal ions. The nuclear relaxation times of carbon atoms of trehalose were shortened by addition of the alkaline-earth chloride salts, MgCl2, CaCl2, and SrCl2, indicating that trehalose formed metal-complexes with the alkaline-earth metal chlorides. From the data of the 1H–1H coupling constants of trehalose in the presence of the alkaline-earth chlorides, it appeared that trehalose formed complexes with MgCl2, and CaCl2 at the various complexing sites: Mg2+ was coordinated to O-4 and O-4′ of trehalose, and Ca2+ to O-2 and O-3. We succeeded in the preparation of two types of crystals of the trehalose/CaCl2. One was a crystal consisting of trehalose, CaCl2, and water in a ratio of 1:1:1. The other was an anhydrous crystal containing trehalose and CaCl2 in a ratio of 1:2. Several applications of the complexing between trehalose and the metal ions for food processing are proposed.

Lactosucrose Inhibits Body Fat Accumulation in Rats by Decreasing Intestinal Lipid Absorption

Lactosucrose (LS, 4G-β-D-galactosylsucrose) is a non-digestible oligosaccharide, and the consumption of LS selectively increases the proportion of intestinal bifidobacteria. We examined in this study the hypolipidemic potential of LS. An oral triolein tolerance test on rats indicated that LS reduced the elevation of serum triglyceride (TG) and free fatty acids (FFA). Furthermore, LS inhibited the enzymatic digestion of triolein by pancreatic lipase in vitro. NMR spectroscopy showed that LS formed an intermolecular complex with triolein. The long-term consumption of a diet containing 5% LS for 8 weeks significantly decreased the weight of abdominal adipose tissue when compared with that of the control group. Thus, LS may reduce adipose tissue accumulation by inhibiting intestinal lipid absorption via a direct interaction with TG.

Suppressive Effect of Trehalose on Acrylamide Formation from Asparagine and Reducing Saccharides

The influence of saccharides on the formation of acrylamide (AcA) was investigated. The reducing saccharides reacted with asaparagine to form AcA, but the non-reducing saccharides, except sucrose, gave no AcA. AcA formation from a mixture containing glucose and asaparagaine was suppressed by the non-reducing saccharides, especially trehalose (76% suppression) and neotrehalose (75% suppression). Glucose is heat-degraded into pyruvaldehyde and 5-hydroxymethyl-2-furfural in the water system. The degradation products react with asparagines to generate AcA. Trehalose appears to inhibit not only the formation of these intermediates and asparagines for AcA, but also the AcA formation from these intermediates.

Effect of Dietary Cyclic Nigerosylnigerose on Intestinal Immune Functions in Mice

We examined the dietary effects of cyclic nigerosylnigerose (CNN), a dietary indigestible oligosaccharide with four D-glucopyranosyl residues linked by alternating α-(1→3)- and α-(1→6) glucosidic linkages, on the intestinal immune function of mice, and the effects were compared with those of α-(1→3)-linked oligosaccharide (nigerooligosaccharides, NOS) or α-(1→6)-linked oligosaccharide (isomaltooligosaccharides, IMO). BALB/c mice were fed with 1–5% CNN, 5% IMO, or 12.5% NOS for 4 weeks, and the intestinal mucosal immune responses were determined. In the 1–5% CNN fed groups, the amounts of IgA in feces increased significantly. In addition, IgA, transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) secretion by Peyer’s patch (PP) cells were enhanced in CNN fed mice. In the 5% CNN group, pH in the cecum decreased, and the amounts of lactic acid and butyric acid increased. These findings were not observed in the NOS- or IMO-fed group of mice. They suggest that CNN supplementation changes the intestinal environment of microflora and indirectly enhances the immune function in the gut.

Production of Isocyclomaltopentaose from Starch Using Isocyclomaltooligosaccharide Glucanotransferase

Production of a novel cyclomaltopentaose cyclized by an α-1,6-linkage, [ICG5; cyclo-{→6)-α-D-Glcp-(1→4)-α-D-Glcp-(1→4)-α-D-Glcp-(1→4)-α-D-Glcp-(1→4)-α-D-Glcp-(1→}], from starch was performed using isocyclomaltooligosaccharide glucanotransferase (IGTase) derived from Bacillus circulans AM7. The optimal conditions for ICG5-production from partially hydrolyzed starch were as follows: substrate concentration, 1.0% (w/v); pH, 5.5; temperature, 45 °C; reaction time, 24 h, IGTase, 1.0 unit/g-dry solid (DS); isoamylase, 2,500 units/g-DS. The yield of ICG5 reached 25.9% under optimal conditions. ICG5-production was achieved from partially hydrolyzed starch using a crude enzyme preparation containing IGTase. Finally, ICG5 was obtained in a yield of 17.9% (99.3% purity, 2,681 g-DS). A digestive test with a human salivary amylase, an artificial gastric juice, a pancreatic amylase, and small intestinal enzymes showed that ICG5 was an indigestible oligosaccharide.