Effects of high ß-glucan barley on visceral fat obesity in Japanese individuals: A randomized, double-blind study.

OBJECTIVE: The aim of this study was to investigate whether a diet in which high ß-glucan barley was substituted for rice would reduce visceral fat obesity in Japanese individuals. METHODS: A randomized, double-blind, placebo-controlled intervention study was conducted with 100 Japanese individuals with waist circumference (WC) ≥85 cm for men or ≥90 cm for women and body mass index (BMI) ≥24 kg/m2. Participants were randomly assigned to consume a mixture of rice and either high ß-glucan barley (test group, 4.4 g/d) or ß-glucan-free barley (placebo group) for 12 wk. Blood samples and computed tomography scans were obtained before and after the trial. RESULTS: Both groups showed decreases in body weight and BMI, and these changes were significantly greater in the test group. WC and visceral fat area (VFA) significantly decreased in both groups (VFA: -10.7 cm2 in the test group; -6.8 cm2 in the placebo group). These changes did not differ significantly between the groups. However, a subgroup analysis of participants with VFA ≥100 cm2 showed a significant decrease in the test group, and this decrease was significantly greater than in the placebo group. CONCLUSIONS: The intake of high ß-glucan barley led to significant and safe reductions in VFA, body weight, BMI, and WC in individuals with visceral fat obesity with VFA ≥100 cm2. Barley high in ß-glucan may contribute to preventing visceral fat obesity.

Effect of waxy barley, Kirarimochi, consumption on bowel movements of late-stage elderly residents at Roken nursing home.

BACKGROUND: It is very important for the late-stage elderly to have the least stressful bowel movements for maintaining a good quality of life. It is generally accepted that consuming adequate dietary fiber is a promising method for the prevention and management of stressful bowel movements such as those during constipation. Therefore, we examined the effect of long-term consumption of waxy barley, which is high in dietary fiber, on the bowel movements of the late-stage elderly living at Roken nursing home (a geriatric health services facility), Japan. METHODS: We compared the defecation and laxative administration frequencies of the subjects before and after waxy barley consumption, for which we served 28 residents a boiled mixture of rice and waxy barley (variety name, Kirarimochi) as the main meals for 5 months, from November to March. In October, all residents were served boiled rice as the main meals. RESULTS: The residents were categorized into "constipated" subjects and "non-constipated" subjects according to their weekly defecation frequency during October. Among the 14 residents categorized as constipated subjects, monthly number of days with defecation in November, January, and March significantly increased in comparison to monthly number of days with defecation in October. In addition, monthly number of days with laxative administration significantly decreased in December and February in comparison to monthly number of days with laxative administration in October. In contrast, the defecation and laxative administration frequencies did not change after waxy barley consumption among the 14 residents categorized as non-constipated subjects. CONCLUSIONS: Consumption of waxy barley, Kirarimochi, for 5 months improved the bowel movements of the constipated subjects; however, the consumption had no effect on the bowel movements of the non-constipated subjects at Roken nursing home. These results indicate that consuming waxy barley, Kirarimochi, is beneficial for the management of constipation in the late-stage elderly residents at Roken nursing home.

A rice family 9 glycoside hydrolase isozyme with broad substrate specificity for hemicelluloses in type II cell walls.

An auxin analog, 2,4-D, stimulates the activity of endo-1,4-beta-glucanase (EGase) in rice (Oryza sativa L.). The auxin-induced activity from three protein fractions was purified to homogeneity from primary root tissues (based on SDS-PAGE and isoelectric focusing after Coomassie brilliant blue staining). Amino acid sequencing indicated that the 20 N-terminal amino acid sequence of the three proteins was identical, suggesting that these proteins may be cognates of one EGase gene. An internal amino acid sequence of the the rice EGase (LVGGYYDAGDNVK) revealed that this enzyme belongs to glycosyl hydrolase family 9 (GHF9). The major isoform of this rice GHF9 [molecular weight based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): 51,216, isoelectric point (pI): 5.5] specifically hydrolyzed 1,4-beta-glycosyl linkages of carboxymethyl (CM)-cellulose, phosphoric acid-swollen cellulose, 1,3-1,4-beta-glucan, arabinoxylan, xylan, glucomannan, cellooligosaccharides [with a degree of polymerization (DP) >3] and 1,4-beta-xylohexaose, indicating a broader substrate range compared with those of other characterized GHF9 enzymes or EGases from higher plants. Hydrolytic products of two major hemicellulosic polysaccharides in type II cell walls treated with the purified enzyme were profiled using high-performance anion exchange chromatography (HPAEC). The results suggested that endolytic attack by rice EGase is not restricted to either the cellulose-like domain of 1,3-1,4-beta-glucan or the unsubstituted 1,4-beta-xylosyl backbone of arabinoxylan, but results in the release of smaller oligosaccharides (DP <6) from graminaceous hemicelluloses. The comparatively broader substrate range of this EGase with respect to beta-1,4-glycan backbones (glucose and xylose) may partly reflect different roles of gramineous and non-gramineous GHF9 enzymes.

Carbohydrate-binding module of a rice endo-beta-1,4-glycanase, OsCel9A, expressed in auxin-induced lateral root primordia, is post-translationally truncated.

We report the cloning of a glycoside hydrolase family (GHF) 9 gene of rice (Oryza sativa L. cv. Sasanishiki), OsCel9A, corresponding to the auxin-induced 51 kDa endo-1,4-beta-glucanase (EGase). This enzyme reveals a broad substrate specificity with respect to sugar backbones (glucose and xylose) in beta-1,4-glycans of type II cell wall. OsCel9A encodes a 640 amino acid polypeptide and is an ortholog of TomCel8, a tomato EGase containing a carbohydrate-binding module (CBM) 2 sequence at its C-terminus. The expression of four rice EGase genes including OsCel9A showed different patterns of organ specificity and responses to auxin. OsCel9A was preferentially expressed during the initiation of lateral roots or subcultured root calli, but was hardly expressed during auxin-induced coleoptile elongation or in seed calli, in contrast to OsCel9D, a KORRIGAN (KOR) homolog. In situ localization of OsCel9A transcripts demonstrated that its expression was specifically up-regulated in lateral root primordia (LRP). Northern blotting analysis showed the presence of a single product of OsCel9A. In contrast, both mass spectrometric analyses of peptide fragments from purified 51 kDa EGase proteins and immunogel blot analysis of EGase proteins in root extracts using two antibodies against internal peptide sequences of OsCel9A revealed that the entire CBM2 region was post-translationally truncated from the 67 kDa nascent protein to generate 51 kDa EGase isoforms. Analyses of auxin concentration and time course dependence of accumulation of two EGase isoforms suggested that the translation and post-translational CBM2 truncation of the OsCel9A gene may participate in lateral root development.